United States Patent	5,437,120
Dornaus	August 1, 1995

Firearm having improved safety and accuracy features

Abstract

An improved firearm having a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays is disclosed. The passive firing pin block prevents accidental discharge when the gun is dropped. The hammer drop mechanism permits the hammer to be safely lowered when a cartridge is present in the chamber without actuating the trigger. The V-block type barrel bushing accurately repositions the forward end of the barrel relative to the sights.-to provide maximum accuracy. The square sight inlays allow the user to quickly and precisely aim the firearm.

Inventors:	Dornaus; Thomas F. (Norwalk, CA)
Assignee:	Voit; Richard A. (Ketchum, ID)
Appl. No.:	165267
Filed:	December 10, 1993

Current U.S. Class:	42/70.08
Intern'l Class:	F41A 017/64
Field of Search:	42/69.03,70.01,70.08 89/139,145,149,150,154

References Cited [Referenced By]

U.S. Patent Documents

D292112	Sep., 1987	Ruger et al.	D22/104.
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891510	Jun., 1908	Tansley	89/148.
917723	Apr., 1909	Ehbets	89/148.
1348284	Aug., 1920	Loomis	89/196.
1382197	Jun., 1921	Jolidon	89/163.
2438601	Mar., 1948	Davis	33/257.
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2846925	Aug., 1958	Norman	89/145.
2935000	May., 1960	Mowrey	89/143.
3158064	Nov., 1964	Charron	89/196.
3371441	Mar., 1968	Walther	42/70.
3411408	Nov., 1968	Pachmayr et al.	89/196.
3495339	Feb., 1970	Elliason	33/257.
3564967	Feb., 1971	La Violette	89/163.
3577668	May., 1971	Ruger	42/70.
3641676	Feb., 1972	Knutsen et al.	42/100.
3665630	May., 1972	Taylor	42/12.
3724113	Apr., 1973	Ludwig	42/70.
3748744	Jul., 1973	McClenahan	33/257.
3756121	Sep., 1973	Roy	89/196.
3830002	Aug., 1974	Volkmar	42/70.
3847054	Nov., 1974	Ruger et al.	89/129.
3925902	Dec., 1975	Gevers	33/257.
3942278	Mar., 1976	Schaller et al.	42/70.
4090316	May., 1978	Volkmar	42/70.
4200989	May., 1980	Brouthers	33/257.
4282795	Aug., 1981	Beretta	89/148.
4306487	Dec., 1981	Beretta	89/148.
4313274	Feb., 1982	Ludwig et al.	42/70.
4352317	Oct., 1982	Wilhelm	89/154.
4369593	Jan., 1983	Zedrosser et al.	42/70.
4395839	Aug., 1983	Eder	42/70.
4429617	Feb., 1984	Ruger	89/198.
4454673	Jun., 1984	Meidel	42/70.
4555861	Dec., 1985	Khoury	42/70.
4575963	Mar., 1986	Ruger et al.	42/70.
4577430	Mar., 1986	Ruger et al.	42/69.
4590697	May., 1986	Ruger et al.	42/70.
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4628611	Dec., 1986	Ruffino	33/254.
4658528	Apr., 1987	Ruger	42/71.
4726136	Feb., 1988	Dornaus et al.	42/70.
4771562	Sep., 1988	Ruger	42/71.
4843748	Jul., 1989	Tumd	42/70.
5245776	Sep., 1993	Dornaus	42/70.
Foreign Patent Documents
16044	Apr., 1904	AT	33/233.
200967	Dec., 1958	AT	42/70.
562943	Dec., 1957	BE	33/242.
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2572802	May., 1986	FR	33/241.
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66046	Oct., 1951	GB	42/70.

Other References

"Astra A-80 Pirstol", American Rifleman, vol. 29, No. 9.
"This DA Auto Handles Five Calibers" Shooting Times, May 1974.

Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Stetina Brunda & Buyan

Parent Case Text

This application is a division of application Ser. No. 08/079,339, filed Jun. 16, 1993, now abandoned, which is a division of application Ser. No. 07/537,064, filed on Jun. 12, 1990, now U.S. Pat. No. 5,245,776.

Claims

What is claimed is:

1. A passive firing pin lock for a firearm, the firearm having a receiver, a slide, a firing pin disposed within the slide, a sear disposed within the receiver, and a trigger, the trigger having unactuated and actuated positions, the passive firing pin lock comprising:

(a) means having a tab formed thereon, said tab being responsive to a pawl formed upon the sear, said means engaging the firing pin when the trigger is in the unactuated position, said means disengaging said firing pin when the trigger is in the actuated position;

(b) wherein engagement of said firing pin by said means locks said firing pin in place to prevent accidental discharge of the firearm and disengagement of said firing pin by said means permits said firing pin to translate reciprocally to discharge the firearm; and

(c) wherein said tab and said pawl are formed and positioned to permit relative motion therebetween as the slide moves relative to the receiver.

2. The passive firing pin lock as recited in claim 1, wherein:

(a) said means for engaging the firing pin comprises a lever, said lever being pivotally movable within the slide between a safe position and a fire position;

(b) wherein in the safe position said lever engages the firing pin such that the firing pin is prevented from striking a chambered round and in the fire position said lever is disengaged from the firing pin such that the firing pin is permitted to strike a chambered cartridge; and

(c) wherein said lever is in the safe position when the trigger is in the unactuated position and said lever is in the fire position when the trigger is in the actuated position.

3. A passive firing pin lock for a firearm, the firearm having a receiver, a slide, a firing pin disposed within the slide, a sear disposed within the receiver, a trigger, and a chambered cartridge, the trigger having unactuated and actuated positions, the passive firing pin lock comprising:

(a) a lever having a tab formed thereon, said lever pivotally movable within the slide between a safe position and a fire position;

(b) a pawl formed upon the sear for engaging said tab;

(c) wherein in the safe position said lever engages the firing pin such that the firing pin is prevented from striking the chambered cartridge and in the fire position said lever is disengaged from the firing pin such that the firing pin is permitted to strike the chambered cartridge;

(d) wherein said lever is in the safe position when the trigger is in the unactuated position and said lever is in the fire position when the trigger is in the actuated position; and

(e) wherein said tab and said pawl are formed and positioned to permit relative motion therebetween as the slide moves relative to the receiver.

4. The passive firing pin lock as recited in claim 3 wherein:

(a) said lever is biased in the safe position by a spring; and

(b) said lever is urged into the fire position by the sear in response to the trigger being moved to the actuated position.

5. The passive firing pin lock as recited in claim 4 further comprising:

(a) a recess formed upon the firing pin; and

(b) a detent formed upon said lever, said detent being receivable within said recess such that the firing pin is prevented from-striking a chambered round when the lever is in the safe position.

6. A firearm comprising:

(a) a receiver;

(b) a slide having reciprocal motion upon said receiver;

(c) a barrel disposed at least partially with said slide;

(d) a firing pin having reciprocal motion within said slide;

(e) a sear rotatable about a sear pin, said sear disposed within said receiver and having a pawl formed thereon;

(f) a hammer disposed proximate said sear for striking said firing pin in response to rotation of said sear, said hammer having cocked and decocked positions;

(g) a trigger mechanically linked to said sear for causing rotation of said sear, said trigger having unactuated and actuated position;

(h) a first means having a tab formed thereon for engaging said pawl and being responsive to said sear for engaging said firing pin when said trigger is in the unactuated position, said first means disengaging said firing pin when said trigger is in the actuated position;

(i) a second means for positioning said firing pin such that said hammer is incapable of striking said firing pin and for subsequently causing said hammer to rotate from the cocked position to the decocked position;

(j) wherein engagement of said firing pin by said first means locks said firing pin in place to prevent accidental discharge of the firearm and disengagement permits said firing pin to translate reciprocally to discharge the firearm; and

(k) wherein said tab and said pawl are formed and positioned to permit relative motion therebetween as the slide moves relative to the receiver.

7. A passive firing pin lock for a firearm, the firearm having a receiver, a slide, a firing pin disposed within the slide, a sear disposed within the receiver, a trigger, and a chambered cartridge, the trigger having unactuated and actuated positions, the passive firing pin lock comprising:

(a) a lever, said lever pivotally movable within the slide between a safe position and a fire position and biased in the safe position by a spring;

(b) a recess formed upon the firing pin;

(c) a detent formed upon said lever, said detent being receivable within said recess such that the firing pin is prevented from striking a chambered cartridge when the lever is in the safe position and said detent is disengaged from said recess such that the firing pin is permitted to strike the chambered cartridge when the lever is in the fire position;

(d) a tab formed upon said lever;

(e) a pawl formed upon said sear for engaging said tab;

(f) wherein said tab and said pawl are formed and positioned to permit relative motion therebetween as the slide moves relative to the receiver; and

(g) wherein said lever is in the safe position when the trigger is in the unactuated position and said lever is in the fire position when the trigger is in the actuated position, said lever being urged into the fire position by the sear in response to the trigger being moved to the actuated position.

Description

FIELD OF THE INVENTION

The present invention relates generally to firearms and more particularly to an improved firearm having a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays.

BACKGROUND OF THE INVENTION

Firearms having inertial firing pins which, when struck by the hammer of the firearm, are driven forward to strike and discharge a cartridge are well known. Several devices have been proposed to selectively lock the firing pin in order to prevent the firearm from being accidentally discharged. Such accidental discharge may occur in the event that the firearm is dropped from a distance of several feet and subsequently lands in such a manner that inertia carries the firing pin forward, thus causing it to strike the cartridge

Manual firing pin locks are well known. They are typically located within the slide of an automatic or semi-automatic pistol and function to prevent the firing pin from contacting a chambered cartridge when activated. There is a tendency not to activate such manually operated firing pin lock mechanisms when it is anticipated that rapid and unexpected use of the gun may be required, during law enforcement or combat use in such situations, the user does not want to be forced to remember to disengage the firing pin lock under stressful conditions, nor does he want to take the time to do so.

Passive firing pin locks such as that described in U.S. Pat. No. 4,555,861 issued to Khoury are known. Such devices have the advantage of not requiring the user to manually engage and disengage the lock. Rather, the lock is automatically engaged when the trigger is in the non-depressed or unactuated position and is automatically disengaged when the trigger is in the depressed or actuated position.

Prior art passive firing pin locks such as the Khoury device suffer, however, from the inherent deficiency that the firing pin is necessarily free to travel forward any time the trigger is depressed, including during the chambering of a cartridge. In such firearms, a malfunction of the disconnector or sear can cause a normally semiautomatic gun to function in a fully automatic mode. A semiautomatic firearm discharges one cartridge each time the trigger is pulled. A fully automatic firearm continues to fire as long as the trigger is depressed and cartridges remain to be fired. Unexpected fully automatic operation could result in the firearm being discharged in an inappropriate direction, possibly resulting in injury or death. Since fully automatic operation requires a stronger grip on the firearm and a firm stance to maintain control of the firearm.

Additionally, since in the Khoury device the firing pin lock does not re-engage the firing pin until the trigger is released, it is possible that an accidental discharge could occur prior to releasing the trigger. For example, in a combat environment the firearm could be struck by a bullet or shrapnel immediately after the firearm has been fired but prior to releasing the trigger. During this time the passive firing pin lock of the Khoury device would be inactive and therefore would not function to prevent the firing pin from being driven forward and discharging the weapon. Therefore, it is possible that an accidental discharge could occur. Also, it is conceivable that the user could fall and permit the firearm to strike a hard surface prior to releasing the trigger, thus driving the firing pin forward and accidentally discharging the firearm.

It would therefore be desireable to lock the firing pin in a retracted position at all times except when it is explicitly desired that the firearm be discharged. This would prevent both unexpected fully automatic operation and accidental discharge.

Also, such contemporary passive .firing pin locks are comparatively complex in their structure. The Khoury device is typical in this regard and includes a double lever and pin arrangement which is comparatively prone to malfunction due to excessive wear, Contamination, or breakage. It would therefore be desirable to provide a mechanically simpler mechanism for preventing undesired forward motion of the firing pin.

Double action semi-automatic pistols are also well known in the art. Pulling the trigger of a double action pistol both cocks the hammer and causes it to fall upon the firing pin. This eliminates the need to separately cock the hammer prior to pulling the trigger. Thus, double action pistols are more effective when quick and unexpected use may be required.

Since the hammer of a double action semi-automatic pistol does not have to be separately cocked and the pistol is therefore capable of being fired by merely pulling the trigger, it is often desireable to keep a cartridge in the chamber. This permits rapid use of the pistol by merely aiming and pulling the trigger. To chamber a cartridge, the slide is pulled back and released, thereby stripping the top cartridge from the magazine and loading it into the chamber. This action also cocks the hammer of the pistol and leaves the hammer in a cocked position.

After chambering a cartridge, the hammer remains in a cocked position such that pulling the trigger will discharge the weapon. Various safety mechanisms are known for preventing inadvertent discharge of the firearm when the trigger is pulled while the hammer is in a cocked position. Such safety mechanisms generally either prevent the sear from releasing the hammer, lock the hammer in the cocked position, or prevent the trigger from being pulled. However, as with the manual firing pin lock, the use of such a safety mechanism is often undesirable when rapid and expected use is likely.

Thus, it is often desireable to have a cartridge chambered, but due to the double action operation of the pistol, it is not necessary to maintain the hammer in a cocked position. Indeed, it is frequently more desireable to maintain the hammer in a decocked position. This is because it takes a substantially greater amount of force to depress the trigger and discharge the firearm when the hammer is in the decocked position. As such, additional force must be provided by the user to cock the hammer, instead of merely releasing it to fall upon the firing pin (i.e. it requires a much more deliberate action to depress the trigger of a decocked double action firearm than to depress the trigger of a cocked double action firearm). This additional force is necessary to overcome the hammer spring tension as the hammer is raised to the cocked position. Such additional force makes an accidental discharge less likely. For example, if a foreign object inadvertently engages the trigger, it is much less likely that an accidental discharge will occur if the hammer is decocked.

Therefore, a common problem associated with double action semi-automatic pistols is the safe lowering of the hammer after manually chambering a cartridge. It may be desired to lower the hammer, thus decocking the firearm, when the gun is to be carried in a holster, stored for an extended period of time, or when it is otherwise desireable not to have the hammer in a cocked position. Many police departments require that their officers carry their firearm with a cartridge in the chamber and the hammer in a decocked position.

A common method for decocking a firearm is to grasp the hammer with the fingers of one hand while holding the firearm in the other hand and pulling the trigger. Grasping the hammer prevents it from falling forcefully upon the firing pin and thus discharging the gun. However, occurrences of inadvertent discharges while attempting this procedure are not uncommon. Since such inadvertent discharges can cause injury and death, it is very desireable to provide a means for lowering the hammer of such a firearm in a safe and convenient manner.

Various decocking or hammer drop mechanisms are known. One such mechanism slowly lowers the hammer to its decocked position such that the hammer does not strike the firing pin with enough force to drive the firing pin into the chambered cartridge. Another mechanism rotates a portion of the firing pin out of the path of the falling hammer such that the hammer cannot strike the end of the firing pin. In this instance the trigger may be pulled to cause the hammer to drop, since it is prevented from striking the displaced firing pin. Alternatively, the mechanism which displaces the portion of the firing pin may also cause the hammer to drop.

A means for lowering the hammer in a single action semi-automatic pistol would likewise be desireable since it is often desired to maintain a single action semi-automatic pistol with a chambered cartridge. This is true even though the hammer of a single action pistol must be separately cocked prior to firing the first cartridge.

Additionally, in the prior art, much weight has been given to the ability of the barrel bushing to firmly secure the front end of the barrel in position. The accuracy of the firearm depends upon the repeatability with which the barrel can be repositioned relative to the sights.

Various bushings for repositioning the forward end of the barrel after each shot are well known. The simplest of such bushings merely receive the front end of the barrel, holding it in place until the firearm is discharged. During discharge, the bushing travels rearward along the barrel. When the barrel unlocks from the slide, the bushing permits slight rotation of the barrel relative to the slide. Such rotation is necessary to accommodate the unlocking/locking motion of the barrel. Such simple bushings must therefore incorporate a slightly oval, elongated, or oversized central aperture.

Through the use of close tolerances, an attempt is made to securely restrain the forward end of the barrel within the bushing prior to discharging the firearm. The requirement for such close tolerances causes the firearm's accuracy to degrade as the bushing wears and the tolerances are lost. Also, close tolerances require the mechanism be maintained comparatively free from contamination. Dirt, sand, lint, and other contaminants can cause the bushing to bind upon the barrel and jam the firearm. The use of close tolerances increases the rate at which the barrel bushing wears due to friction. Fabrication of barrel bushings having close tolerances is comparatively difficult and expensive.

Thus, the prior art has concentrated efforts for achieving superior accuracy upon the ability of the barrel bushing to firmly secure the forward end of the barrel in position. Other mechanisms, such as Colt's collet type barrel bushing, disclosed in U.S. Pat. No. 3,564,967 issued to La Violette have been used to achieve this result. All such methods of firmly securing the forward end of the barrel in position are characterized by the requirement for closely held tolerances which tend to degrade over time and thus cause the firearm's accuracy to deteriorate.

Another common problem with prior art bushings is cracking due to the repeated application of stress when the gun is fired. This is particularly true of the Colt collet type bushing wherein comparatively delicate fingers secure the barrel in place. Such fingers are subject to the development of stress cracks. Consequently, they occasionally break off whereupon they may cause the gun to jam.

It would be desirable to repeatably position the barrel without requiring that the forward end of the barrel be firmly secured in place. It would also be desireable to eliminate the need for close tolerance in the fabrication of barrel bushings. Additionally, it would be desireable to provide a barrel bushing which is not susceptible to malfunction due to stress.

In addition, colored inlays formed upon the front and rear sights of firearms for aiding the user in the aiming process are well known. Typically a single round or rectangular inlay is provided upon the firearms front sight and two round inlays are provide on either side of the central groove of the rear site. Such inlays are typically colored either white or red to provide a stark contrast to the deep blue or black color of the gun sights. The use of colored inlays provides highly visible reference points by which the user can quickly align the sights upon a target.

Such inlays are used by aligning the inlay formed upon the front sight between the two inlays formed upon the rear sights. This process is hastened by the ease with which the colored inlays are perceived by the user. The red or white inlays can be quickly spotted and rapidly brought into rough alignment.

However, precise alignment of the prior art inlays is relatively difficult. The curved peripheries of the round inlays used upon the rear-and/or front sights do not provide an easy means for judging alignment. In the prior art, the user must either align round rear inlays to a round front inlay or round rear inlays to a rectangular front inlay.

As will be recognized, it is difficult to align curved lines to each other or to a straight line. The curved lines do not provide a single reference for alignment, but rather present the user with the task of defining a reference. The user must align the round inlay by concentrating upon some portion thereof. For example, the user may attempt to visually determine the center point of the round inlay on the front sight and align it to similarly determined center points on round inlays of the rear sights.

Thus, although prior art firearms have proven generally suitable for their intended purposes, they possess inherent deficiencies which detract from their safe use and reduce accuracy below that theoretically obtainable. This detracts from their overall effectiveness in the marketplace.

In view of the shortcomings of the prior art, it is desirable to provide an improved firearm having a trigger actuated passive firing pin lock, a convenient and safe means for lowering the hammer of a firearm having a chambered cartridge, a barrel bushing which accurately repositions the forward end of the barrel relative to the sights, and sight inlays which allow the user to quickly and precisely aim the firearm.

SUMMARY OF THE INVENTION

The present invention specifically addresses and alleviates the above mentioned deficiencies associated in the prior art. More particularly, the present invention comprises an improved firearm having one or more safety and performance features such as a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays.

The passive firing pin lock of the present invention prevents an accidental discharge when the gun is dropped. The passive firing pin lock is comprised of a lever which engages the firing pin and locks the firing pin in position such that the firing pin cannot travel forward and discharge a chambered cartridge. The lever pivots about a pin between an engaged or safe position and a disengaged or fire position. The lever is biased in the safe position by a spring.

Pulling the trigger rotates the sear to disengage a catch formed upon the sear from a notch formed upon the hammer and thus permits the hammer to fall. Prior to rotating sufficiently to cause the hammer to fall, a paw formed upon the sear engages a tab formed upon the passive firing pin lock lever, thus causing the lever to disengage the firing pin. This places the lever in the fire position wherein further rotation of the sear will cause the hammer to drop upon the firing pin and drive the firing pin forward, thus discharging the firearm.

Upon ignition of the propellant contained within the cartridge, the firing pin is immediately urged rearward by both the firing pin spring and a dynamic impulse imparted as gas pressure tends to re-flatten the primer. Upon retraction to its original position, the firing pin is immediately locked into place by the passive firing pin lock lever. This occurs prior to the user releasing the trigger. Thus, the firing pin is immediately locked into a safe position and the gun is thereby protected from accidental discharge.

By immediately locking the firing pin in a safe position, prior even to releasing the trigger, the probability of an accidental discharge is substantially reduced. For instance, if the gun should be forcibly struck, i.e. by a bullet or shrapnel, immediately after a shot has been fired, but prior to releasing the trigger, the firing pin will have been locked in a safe position and the gun will be prevented from discharging. Also, in the event that the user falls after firing a shot but prior to releasing the trigger, and the gun strikes a hard surface with sufficient force to drive the firing pin forward, the gun is again prevented from discharging.

The manufacture of a pistol having the passive firing pin lock of the present invention essentially involves the fabrication of a lever and a modification of the sear. By contrast, manufacture of the Khoury device involves the fabrication of two separate lever mechanisms and a pin lock. Thus, manufacture of the firing pin lock of the present invention involves fewer materials, less machining, and simplified assembly. This provides a substantial savings in manufacturing costs.

Additionally, locking of the firing pin in the safe position without the necessity of the trigger being released precludes the possibility that the pistol could operate in the fully automatic mode in the event of a sear or disconnector malfunction. Operation of the firearm in the fully automatic mode is extremely dangerous since it typically occurs unexpectedly and results in the rapid discharge of several cartridges. In the event of such an occurrence the user often does not maintain full control of the firearm since the discharge of more than one cartridge is not expected. Therefore, several shots could be fired in an unsafe direction, resulting in death or injury. The ability to lock the firing pin in place immediately without the necessity of releasing the trigger therefore reduces the likelihood of such an occurrence.

The passive firing pin lock of the present invention is also particularly well suited for use in a double action only firearm. While most double action firearms can be operated in either a double action or single action mode, double action only firearms can only be fired in a double action mode. Double action only firearms do not have a hammer notch and sear catch for holding the hammer in a cocked position and must therefore be fired from the decocked position, i.e. in a double action mode.

In a double action only firearm it is often desired that the weapon be as simple to operate as possible. Thus, external manually operated safeties are not desirable. It is usually intended that such firearms be capable of being used by merely aiming and pulling the trigger.

Since the hammer of a double action only firearm does not remain in a cocked position after firing, it follows the slide forward as the next round is chambered. The hammer thus pushes the firing pin slightly forward as the slide moves into battery. Therefore, the firing pin may actually contact the primer of a chambered cartridge as the slide is brought into battery. While the firing pin does not strike the primer with sufficient force to cause the firearm to discharge, it is nevertheless undesirable to permit the firing pin to contact the primer except when a discharge is intended.

The passive firing pin lock of the present inventory prevents the firing pin from contacting the primer of a chambered round as the slide is brought into battery. This adds an extra margin of safety to the firearm. The firing pin cannot contact the primer since the firing pin is locked into a retracted position as the slide travels rearward and remains locked as the slide moves forward into battery.

The passive firing pin lock of the present invention thus provides a means whereby a double action only firearm may be constructed without the need for an externally operated manual safety and without permitting the firing pin to contact the primer of a chambered round as the slide moves into battery after the round is chambered.

In addition, the present invention incorporates a novel hammer drop mechanism which permits the hammer to be safely lowered when a cartridge is present in the chamber. This is accomplished without touching the trigger of the firearm. The hammer drop mechanism is comprised of first and second hammer drop shafts which are inserted into the slide at diametrically opposed positions and connect to form a single shaft having three cam surfaces formed thereupon. An external thumb lever formed upon one of the shafts permits the shaft to be manually rotated .by the user. Rotation of the shaft engages two of the cams against the firing pin, thus withdrawing the firing pin beyond the firing pin retainer and into the slide such that the hammer can no longer strike the firing pin. Further rotation of the shafts cams a hammer drop push rod downward against the sear, thus causing the sear to rotate and release the hammer.

The use of two cams to withdraw the firing pin provides redundancy such that the firing pin will be safely retracted in the event of-excessive-wear or malfunction of one of the cams. Thus, even if one cam fails, the firing pin will still be retracted within the slide prior to the hammer falling.

Therefore, in operation the hammer drop mechanism of the present invention first repositions the firing pin within the slide to prevent contact with the hammer and then actuates the hammer causing it to fall to a decocked position. The hammer drop mechanism of the present invention thereby provides a safe and convenient means for a user to lower a semi-automatic pistol's hammer when a cartridge is chambered.

A V-block type barrel bushing of the present invention accurately repositions the forward end of the barrel relative to the sights to provide maximum accuracy. The V-block type barrel bushing of the present invention is comprised of two flat contact surfaces formed as an integral part of the slide and configured to contact the front end of the barrel tangentially at two locations. The use of such a V-block provides an extremely accurate means for repeatably positioning a cylindrical object. Thus, in i the same manner that a machinist might axially position a section of bar stock prior to drilling, the forward portion of the barrel is precisely positioned prior to discharging the pistol.

Since the V-block bushing of the present invention does not attempt to firmly secure the front end of the barrel in place but rather repeatedly locates the front end of the barrel in a consistent position relative the slide, friction is minimized and bushing failure is eliminated. Also, the requirement for close tolerance machining is eliminated since the exact positioning and dimensions of the V-block are unimportant. It is merely necessary that the two contact surfaces be formed at approximately the five and seven o'clock positions and be tangential to the barrel. Use of the V-block barrel bushing of the present invention therefore provides the best accuracy theoretically possible while eliminating the prior art problems of wear and malfunction.

Further, the present invention discloses the use of square sight inlays or indicia. The square sight markings of the present invention are preferably comprised of a single square inlay formed upon the front sight and one square inlay formed upon either side of the groove in the rear sight. The square inlays are positioned such that when all three of their upper and lower edges are aligned and the square inlay formed upon the front sight is centered between the square inlays formed upon the rear sights, then the gun is on target. The advantages of such square inlays lie in the ability to rapidly align their upper and lower edges and the ability to perceive very small discrepancies in alignment.

It is a simple matter for the user to vary the elevation of the gun to achieve alignment of the upper and lower edges of the square inlays. The user simply concentrates upon either the upper or lower edges of the square inlays and tilts the gun o bring them into alignment. When aligned, both the upper and lower edges of the square inlays form a pair of single lines such that any deviations in the alignment of the inlays is immediately apparent and can be corrected.

Alignment of sights having round inlays is far more difficult by comparison. There are no straight lines for the user to bring into alignment. Therefore the user must rely upon his ability to perceive corresponding points within each round inlay and attempt to align these imagined corresponding points. For example, the user may concentrate upon aligning the centers of the round inlays. This is extremely difficult since the centers are only defined within the user's mind and are therefore extremely difficult to align with any precision. The user may also attempt to align the sights by concentrating upon the uppermost portion of the outer perimeter of each round inlay. This is likewise extremely difficult since the precise location of the uppermost point of the perimeter of each round inlay again exists only Within the user's mind. The user must therefore attempt to determine the precise location of either the center, uppermost portion of the perimeter, or some other distinctive portion of each round inlay and do this subconsciously while also aligning the sights upon the target.

Aligning the square inlay sights of the present invention in azimuth is also greatly simplified over contemporary round inlays. In the present invention it is simply necessary to insure that the front sight square inlay is centered between the two rear sight square inlays by rapidly providing an equal distance between each of the two rear sight square inlays and the front square inlay. This is a simple matter since the user is aligning straight vertical lines. That is, it is a simple matter to visually determine the distance between vertical straight lines. By contrast, it is far more difficult to determine the distance between adjacent circular edges. In order to determine the distance between adjacent circular edges, it is first necessary to imagine points upon each of the circular edges from which the determination is to be made. Thus, the user must again use judgement to form an imaginary point upon the circumference of each of the round inlays and to form a mental measurement therebetween.

As such, the square sight inlays of the present invention provide a means of rapidly and accurately aligning the sights upon a target without having to rely upon the user's ability to mentally measure distances between curved objects. The square sight inlays thus allow the user to quickly and precisely aim the firearm.

These, as well as other advantages of the present invention will be more apparent from the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the right side of a semi-automatic pistol in accordance with the preferred embodiment of the present invention;

FIG. 2 is a perspective view of the left side of the semi-automatic pistol of FIG. 1;

FIG. 3 is a perspective view of the passive firing pin lock of the present invention showing the sear, sear housing, passive firing pin lock lever, and the firing pin, the firing pin being shown in the phantom, and the passive firing pin lock lever being shown partially in phantom

FIG. 4 is an exploded view of the sear housing, sear, passive firing pin lock lever, and firing pin of FIG. 3;

FIG. 5 is a perspective view of the sear, passive firing pin lock lever, and a portion of the firing pin of FIG. 4;

FIG. 6 is a sectional view of the sear and a portion of the passive firing pin lock lever taken along line 6--6 of FIG. 5;

FIG. 7 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1;

FIG. 7A is an enlarged cross-sectional side view of the rear portion of the slide and receiver shown in FIG. 7 depicting the hammer in its cocked position, the sear engaging the hammer, and the passive firing pin lock lever positioned to block the forward motion of the firing pin;

FIG. 8 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the hammer in the cocked position, the sear disengaged from the hammer, and the passive firing pin lock lever disengaged from the firing pin;

FIG. 9 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the hammer in the decocked position, the sear disengaged from the hammer, the passive firing pin lock lever disengaged from the firing pin, and the firing pin in its forward most position;

FIG. 10 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the slide in its rear most position, the hammer in its cocked position, the passive firing pin lock lever engaging the firing pin, and the sear engaging the hammer;

FIG. 11 is an exploded perspective view of the hammer drop mechanism of the present invention showing the first and second hammer drop shafts, the rear most portion of the firing pin, the hammer drop push rod, and a portion of the sear;

FIG. 11A is a cross-sectional view of the first and second hammer drop shafts taken along line 11A of FIG. 11 and a roll pin used to attach them together;

FIG. 12 is a perspective view of the second hammer drop shaft, the hammer drop push rod, and a portion of the sear of FIG. 11 showing the cam formed upon the second hammer drop shaft for camming the hammer drop push rod against the sear;

FIG. 13 is a sectional perspective view of a portion of the firing pin of FIG. 11 showing the two camming surfaces upon which the two cams formed upon the first and second hammer drop shafts act;

FIG. 14 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever in the horizontal or unactuated position;

FIG. 14A is an enlarged cross-sectional view of the hammer drop push rod cam engaging the hammer drop push rod as shown in FIG. 14;

FIG. 14B is an enlarged cross-sectional view of the first firing pin cam about to engage the first firing pin camming surface of the firing pin as shown in FIG. 14;

FIG. 14C is an enlarged side view of the second firing pin cam about to engage the second firing pin camming surface as shown in FIG. 14, the second firing pin camming surface being shown in dashed lines;

FIG. 15 is a cross-sectional side-view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever depressed to a position approximately midway in its travel;

FIG. 15A is an enlarged cross-sectional side view of the hammer drop push rod cam engaging the hammer drop push rod as shown in FIG. 15;

FIG. 15B is an enlarged cross-sectional side view of the first firing pin cam engaging the first firing pin camming surface of the firing pin as shown in FIG. 15;

FIG. 15C is an enlarged side view of the second firing pin cam engaging the second firing pin camming surface of the firing pin as shown in FIG. 15;

FIG. 16 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever in its fully depressed position;

FIG. 16A is an enlarged cross-sectional side view of the hammer drop push rod cam depressing the hammer drop push rod as shown in FIG. 16;

FIG. 16B is an enlarged cross-sectional side view of the first firing pin cam engaging the first firing pin camming surface of the firing pin as shown in FIG. 16;

FIG. 16C is an enlarged cross-sectional side view of the second firing pin cam engaging the second firing pin camming surface of FIG. 16;

FIG. 17 is a front view of the V-block bushing of the present invention formed within the slide of the pistol of FIG. 1;

FIG. 18 is a cross-sectional side view of the V-block bushing of FIG. 17;

FIG. 19 is a cross-sectional side view of the rear sight of the pistol of FIG. 1;

FIG. 20 is a cross-sectional view taken about lines 20--20 of the rear sight of FIG. 19 showing the two square inlays of the present invention;

FIG. 21 is a perspective view of the front and rear sights showing the square inlays;

FIG. 22 is a rear view of the front and rear sights of FIG. 21; and

FIG. 23 is a rear view of the slide of the pistol of FIG. 1 showing alignment of the square inlays of the front and rear sights with a bull's-eye.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

The firearm of the present invention is illustrated in FIGS. 1-23 which depict a presently preferred embodiment of the invention. Referring now to FIGS. 1 and 2, a pistol 10 in accordance with the present invention is comprised generally of a receiver 24 and a slide 22 disposed for reciprocal motion upon the receiver 24. A trigger 12 protrudes from the lower portion of receiver 24 to actuate, through conventional internal mechanisms, a hammer 14. A manually operated safety 25 prevents the trigger 12 from discharging the pistol 10 as in the prior art. As is well known, when trigger 12 is actuated, the hammer 14 strikes firing pin striking surface 54 and firing pin retainer 28. Rear 18 and front 20 sights provide for the alignment of barrel 30 with a target. In the preferred embodiment, the pistol 10 comprises a semi-automatic handgun, such as that depicted in U.S. Pat. No. 4,726,136 issued to Dornaus et al. the disclosure of which is expressly incorporated herein by reference. In this regard, the present invention comprises a specific improvement over the hand gun disclosed in U.S. Pat. No. 4,726,136 but is additionally applicable to other types of firearms.

Referring now to FIGS. 3 through 6, the passive firing pin lock of the preferred embodiment of the present invention is depicted. A sear 32 is pivotally disposed within sear housing 36. Sear housing 36 is disposed within the receiver of FIGS. 1 and 2 proximate the hammer 14. The sear 32 pivots about sear pin 34. An arm 48 extends from the sear 32 and has a pawl 50 formed upon the distal end thereof.

Passive firing pin lock lever 38 is pivotally mounted within the slide 22 above the sear 32. Lever 38 pivots about lever pin 41 (shown in FIG. 7 and 7A) which extends through aperture 40 formed in lever.38. Lever 38 has a detent 42 formed upon one end thereof. A tab 46 extends perpendicularly from approximately the middle of the lever 38. A contact surface 52 is formed upon the upper surfaces of the tab 46.

An inertial firing pin 26 is disposed within the slide 22 immediately above the passive firing pin lock lever 38. The firing pin 26 has a recess 44 formed in the lower rear surface thereof and sized to receive the detent 42 formed upon the lever 38. Firing pin striking surface 54 of firing pin 26 extends through the firing pin retainer 28 as shown in FIG. 2.

In the present invention, as well as in the prior art, depression of the trigger 12 is mechanically communicated to the sear 32 via linkage (not shown), thus causing the sear to rotate to permit the hammer 14 to fall upon the firing pin retainer 28 and striking surface 54 of the =ring pin 26 The firing pin 26 is thus driven forward toward the primer of a chambered cartridge, against the biasing force of a firing pin spring 62 (as shown in FIGS. 7-10). The inertia of the firing pin 26 causes it to strike the primer with sufficient force to detonate the primer, thus discharging the firearm.

Clockwise (as viewed in FIG. 3) rotation of the lever 38 engages a detent 42 within a recess 44 formed in the lower rear portion of the firing pin 26. Engagement of the detent 42 within the recess 44 of firing pin 26 thus prevents forward translation of the firing pin 26 within the slide 22. Clockwise rotation of the sear 32 causes the tab 46 formed upon lever 38 to be engaged by pawl 50 of sear 32.

As can be seen in the cross sectional view of FIG. 6, the pawl 50 formed upon the distal end of arm 48 engages contact surface 52 of tab 46 when pawl 50 moves downward in response to clockwise rotation of the sear 32. Thus, clockwise rotation of the sear 32 causes lever 38 to rotate counterclockwise, and to disengage detent 42 from recess 44 of firing pin 26. Detent 42 of the passive firing pin lock lever 38 engages the recess 44 formed within firing pin 26 at all times except when the trigger 12 is depressed to fire the pistol 10.

As in the prior art, Clockwise rotation of the sear 32 disengages the hammer 14 from the sear 32.thus permitting the hammer 14 to fall and strike the firing pin 26. The firing pin 26 travels forward to discharge a chambered round in response to the striking surface 54 of the firing pin 26 being struck by the hammer 14. The detent 42 of the present invention is disengaged from the recess 44 of the firing pin 26 immediately prior to the disengagement of the hammer 14 from the sear 32.

The detent 42 is engaged within the recess 44 of the firing pin 26 at all times other than when the trigger 12 is depressed, thus effectively preventing accidental discharge of the pistol 10. Dropping of the pistol 10 with its barrel downward, such that an accidental discharge would be likely in a prior art pistol, thus does not cause the firing pin 26 to travel forward under the force of its own inertia when the firearm strikes the floor.

Operation of the passive firing pin lock of the present invention is presented in further detail with reference to FIGS. 7-10 wherein the lock is depicted in its various stages of operation as the trigger 12 is pulled and the pistol 10 is discharged.

With particular reference to FIGS. 7 and 7A, the pistol 10 is depicted with the hammer 14 in a cocked position and a cartridge 66 loaded in the chamber 30. The striking surface 54 of the firing pin 26 extends beyond the firing pin retainer 28 such that the hammer 14 will contact the striking surface 54 of the firing pin 26 and drive the firing pin 26 forward toward the cartridge 66 when the hammer 14 is released. Since the trigger has not yet been depressed, detent 42 on lever 38 is received by recess 44 of firing pin 26. Thus, the firing pin 26 is locked in a safe position and thereby prevented from translating forward and striking the cartridge 66. Spring 68 disposed against surface 70 of lever 38 biases lever 38 into this safe position.

If the pistol-were to be dropped while in this safe configuration, the firing pin 26 Would be prevented from moving forward under its own inertia and striking cartridge 66 with the tip 64 thereof. Thus, the probability of death or injury due to accidental discharge is reduced.

The sear catch 74 of sear 32 engages the hammer notch 72 of the hammer 14, thus maintaining the hammer 14 in its cocked position until the trigger 12 is pulled. Pulling the trigger 12 at this point will rotate (through a conventional mechanical linkage which is not shown) the sear 32 clockwise, thus disengaging sear catch 74 from hammer notch 72 and permitting the hammer to rotate clockwise under the biasing of the hammer spring (not shown), whereupon the hammer 14 will strike the striking surface 54 of the firing pin 26 and the firing pin retainer 28. Pawl 50 formed upon the end of arm 48 of the sear 32 does not contact tab 46 of lever 38 when the trigger 12 is not depressed.

With particular reference to FIG. 8, the passive firing pin lock is depicted after the trigger 12 has been depressed. Depressing the trigger 12 has caused the sear 32 to rotate clockwise sufficiently to permit sear catch 74 to disengage from hammer notch 72 such that hammer 14 will begin to rotate clockwise under the urging of the hammer spring (not shown), whereupon the hammer 14 will strike striking surface 54 and firing pin retainer 28. Immediately prior to sear catch 74 disengaging hammer notch 72, pawl 50 contacts tab 46 of the lever 38 and urges tab 46 downwardly. This causes detent 42 to disengage from recess 44. Thus, as hammer 14 rotates clockwise to strike the striking surface 54 of firing pin 26, firing pin 26 is unlocked from its safe configuration and placed in a fire configuration wherein firing pin 26 is free to travel forward to cause the discharge of the pistol 10.

With particular reference to FIG. 9, hammer 14 has struck the striking surface 54 of the firing pin 26, thus driving the firing pin 28 forward against the urging of spring 62. The tip 64 of firing pin 26 thus strikes cartridge 66 to discharge the pistol 10. The pawl 50 of the sear 32 holds the lever 38 in the fire configuration as the firing pin 26 rebounds rearward under the urging of spring 62.

With particular reference to FIG. 10, the reaction to the lead bullet moving forward causes the slide 22 to rapidly recoil longitudinally rearward, thus cocking the hammer 14, extracting the expended cartridge, and permitting another cartridge to be chambered. As the slide 22 travels rearward, tab 46 of lever 38 disengages sear pawl 50, thus permitting detent 42 to be again received by recess 44 of the firing pin 26.

Therefore, firing pin 26 is once again locked into the safe configuration before slide 22 returns to its rest position. As in the prior art, sear 32 rotates counterclockwise such that sear catch 74 engages hammer notch 72 thus preventing the hammer 14 from rotating clockwise and again striking the striking surface 54 of the firing pin 26. Thus, as the slide returns to its forward most position, the safe configuration of the firing pin 26 is once again attained.

Referring now to FIGS. 11 through 13, the hammer drop mechanism of the present invention is depicted. The hammer drop mechanism is generally comprised of first 100 and second 102 shafts, the firing pin 26, hammer drop push rod 104, and sear 32. The first shaft 100 has a thumb actuation lever 106 formed upon one end thereof and a shaft recess 110 and second firing pin cam 108 formed upon the opposite end thereof. The second shaft 102 has a flat shaft portion 112, a first firing pin cam 114 and a hammer drop cam 116 formed thereupon.

First 100 and second 102 shafts are inserted into the slide 22 such that they may be attached together with 101 to form a single shaft which passes transversely through the slide 22 Pin 101 extends through aperture 119 in second shaft 102 and through aperture 121 in first shaft 100. Therefore, rotation of the first shaft 100 by depressing thumb lever 106 causes a like rotation of second shaft 102.

With particular reference to FIG. 12, the upper end 118 of hammer drop push rod 104 contacts the hammer drop cam 116 of second shaft 102 and the lower ed 120 contacts the arm 48 of the sear 32. The flat shaft portion 112 is formed to be received by the shaft recess 110 of the first shaft 100. Thus, first shaft 100 and second shaft 102 attach together to form a single rotatable member.

With particular reference to FIG. 13, the firing pin 26 includes a first camming surface 124 and a second camming surface 122 formed thereon. The first camming surface 124 is adapted to engage the first firing pin cam 114 and the second surface 122 is adapted to engage the second firing pin cam 108.

The firing pin 26 is prevented from rotating about its longitudinal axis by the abutment of the lower surface 115 of the second shaft 102 against the upper flat surface 127 of recess 126 formed in the firing pin 26 and by the abutment of the edge 117 of the first shaft 100 against the flat side 125 of the firing pin 26.

Operation of the hammer drop mechanism of the present invention is presented in detail with reference to FIGS. 14-16C wherein the mechanism is depicted in various stages of operation as the thumb lever is depressed. Thumb lever 106 is biased in the up or unactuated position by the firing pin spring 62 acting through the firing pin 26 and by the hammer drop pin spring 105 acting through the hammer drop pin 104. Actuation of the thumb lever 106 cams the firing pin 26 into the slide 22 such that the striking surface 54 of the firing pin 26 is disposed beneath the hammer striking or outer surface 29 of the firing pin retainer 28 and consequently cannot be struck by the hammer 14. Further rotation of the thumb lever 106 actuates the sear 32, thus releasing the hammer 14 and permitting it to fall to a decocked position.

With particular reference to FIG. 14, the firing pin 26 is depicted in its rest position. The striking surface 54 of the firing pin 26 extends beyond the hammer striking or outer surface 29 of the firing pin retainer 28. The hammer drop cam 116 lightly contacts the upper end 118 of the hammer drop push rod 104. The first firing pin cam 114 is positioned almost in contact with the first camming surface 124 of the firing pin 26. The second firing pin cam 108 is positioned slightly above the second camming surface 122 of the firing pin 26. The hammer 14 is shown in the cocked position and maintained therein by the sear 32.

The hammer drop push rod 104 is disposed intermediate the second shaft 102 and the sear 32 such that rotation of the second shaft 102 in a clockwise direction by manipulation of the lever 106 will cause the hammer drop cam 116 to abut the uppermost end 118 of the hammer drop push rod 104 and translate the lower end 120 of he hammer drop push rod 104 downwardly against the bias of hammer drop push rod spring 105 into contact with the arm 48 of the sear 32. Continued rotation of the second shaft 102 in the clockwise direction rotates the arm 48 of the sear 32 downward, thus causing the sear catch 74 of the sear 32 to disengage the hammer notch 72 of the hammer 14. This permits the hammer 14 to rotate clockwise under the urging of the hammer spring (not shown). The three camming actions are discussed and illustrated in greater detail with respect to FIGS. 14A-14C.

With particular reference to FIG. 14A, when the thumb lever 106 is in the horizontal or rest position as in FIG. 14, the hammer drop cam 116 abuts the upper end 118 of the hammer drop push rod 104 without urging the hammer drop push rod 104 downward. That is, the upper end 118 of the hammer drop push rod 104 contacts the hammer drop cam 116 of the second hammer drop shaft 102 under the urging of hammer drop push rod spring 105 and there is no downward force upon the hammer drop push rod 104.

With particular reference to FIG. 14B, with the thumb lever 106 in the horizontal or rest position as in FIG. 14, the first firing pin cam 114 is positioned almost in contact with the first camming surface 124 of the firing pin 26 without urging the firing pin 26 forward.

With particular reference to FIG. 14C, with the thumb lever 106 in the horizontal or rest position as in FIG. 14, the second firing pin cam 108 does not contact the second camming surface 122 of the firing pin 26.

Referring now to FIGS. 15-15C, the positions and interactions of the various components of the hammer drop mechanism of the present invention are shown when the thumb lever 106 has been rotated clockwise through approximately one half of its travel i.e. approximately 30 degrees from its initial at rest position of FIGS. 14A-14C. Rotating the thumb lever 106 to an intermediate position brings the hammer drop cam 116 firmly into contact with the upper end 118 of the hammer drop push rod 104. The hammer drop push rod 104 may translate downward slightly, but not sufficiently to cause rotation of the sear 32. Such rotation of the thumb lever 106 also causes first 114 and second 108 firing pin cams to begin camming the firing pin 26 forward such that the firing pin 26 is partially withdrawn into the slide 22.

In this position, the striking surface 54 of the firing pin 26 is approximately flush with the outer surface 29 of the firing pin retainer 28. Therefore, the firing pin 26 is withdrawn to a point where the dropping hammer 14 is incapable of driving the firing pin 26 forward to discharge the pistol 10. The firing pin 26 is withdrawn in this manner prior to initiating the process of disengaging the sear 32 from the hammer 14. That is, the hammer is prevented from falling upon the striker plate 28 until the firing pin 26 is well beneath the outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 15A, with the thumb lever 106 in an intermediate position as in FIG. 15, the hammer drop cam 116 is brought into firm contact with the upper end 118 of the hammer drop push rod 104 such that slight pressure begins to be applied to the arm 48 of the sear 32. The hammer drop cam 116 has not yet begun to urge hammer drop push rod 104 appreciably downward. Thus, the sear 32 does not yet begin to rotate clockwise and the sear catch 74 consequently firmly engages hammer notch 72 of the hammer 14.

With particular reference to FIG. 15B, with the thumb lever 106 in an intermediate position as in FIG. 15, first firing pin cam 114 has urged firing pin 26 forward sufficiently to bring the striking surface 54 of the firing pin 26 approximately flush with the outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 15C, with the thumb lever 106 in an intermediate position as in FIG. 15, second firing pin cam 108 provides a redundant means for urging firing pin 26 forward as thumb lever 106 is depressed. Second firing pin cam 108 abuts camming surface 122 formed upon firing pin 26 to simultaneously urge firing pin 26 forward in concert with cam 114 and camming surface 124. The redundant camming action assures that the striking surface 54 of the firing pin 26 is safely withdrawn into the slide 22 prior to dropping of the hammer 14. Thus, even in the event of wear or malfunction of one of the first 114 and second 108 firing pin cams and/or their corresponding camming surfaces 124 and 122, a safe means for lowering the hammer is maintained.

Referring now to FIGS. 16-16C, the position of the hammer drop mechanism as the thumb lever 106 is rotated through its full travel i.e., approximately 60 degrees from its initial at rest positio of FIGS. 14A-14C is depicted. As the thumb lever 106 nears the completion of its travel to the fully clockwise rotational position, the striking surface 54 of the firing pin 26 is withdrawn well below the outer surface 29 of the firing pin retainer 28 and the sear catch 74 disengages the hammer notch 72, thus allowing the hammer 14 to fall to a decocked position.

With particular reference to FIG. 16, the hammer has dropped from its cocked position and rests upon the firing pin retainer 28. With the thumb lever 106 in its fully rotated posiion the firing pin 26 is cammed forward such that the striking surface 54 thereof is disposed within the firing pin retainer 28 and cannot be contacted by the hammer 14 as the hammer 14 falls. The hammer 14 is prevented from striking the firing pin 26 and thereby discharging the pistol.

Thumb lever 106 and the rotatable member comprised of first 100 and second 102 shafts thus provide a single or common means for withdrawing the firing pin 26 and lowering the hammer 14. The three camming actions are discussed and illustrated in greater detail with respect to FIGS. 16A-16C.

With particular reference to FIG. 16A, it can be seen that the hammer drop cam 116 has urged the hammer drop push rod 104 against the urging of hammer drop push rod spring 105 fully to its lowermost position wherein the hammer drop push rod 104 has urged the sear 32 to rotate in a clockwise direction, thereby disengaging the sear catch 74 from the hammer notch 72.

With particular reference to FIG. 16B, with the lever 106 fully depressed as in FIG. 16 the first firing pin cam 114 has urged the firing pin 26 forward sufficiently to withdraw the striking surface 54 of the firing pin 26 beyond the hammer striking or outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 16C, with the thumb lever 106 fully depressed as in FIG. 16, in redundant fashion the second firing pin cam 108 has urged the firing pin 26 forward. The redundant operation of the first 114 and second 108 firing pin cams insures that the firing pin 28 is safely withdrawn beyond the hammer striking or outer surface 29 of the firing pin retainer 28 before the hammer 14 is released by the sear 32 to strike the firing pin retainer 28. Thus, the hammer 14 is safely decocked without discharging the pistol 10.

In addition to the improved safety features obtained by the present invention's use of the passive firing pin lock mechanism and hammer drop mechanism, the present invention provides improved performance characteristics by use of a V-block bushing and square front and rear sight system. Referring more particularly to FIGS. 17 and 18, the V-block bushing feature of the present invention is illustrated. As is conventional, the-distal end of the slide 22 is provided with a bushing 55 which is threadingly inserted or press fit therewithin. The purpose of the bushing is to maintain the distal end of the barrel which is disposed within the interior of the slide 22 and position the distal end of the barrel at a repeatable location relative the slide 22 prior to discharge of pistol 10.

In contrast to prior art bushings, the bushing 55 of the present invention comprises a V-block bushing having a pair of tangential flats 56 formed adjacent its lower periphery adapted to tangentially contact the exterior diameter of the barrel 3l. As best shown in FIG. 17, with the barrel 31 disposed in its fire position the exterior of the barrel 31 contacts the flats 56 formed on the V-block bushing 55 to axially center the barrel 31 relative the bushing 55 and thus the slide 22. Due to the barrel 31 being pivotally connected to the slide adjacent its opposite end and is thereby urged downwardly upon the flats 56 by lever action, the lower diameter of the barrel 31 contact the flats 56 at two tangential points, i.e. contact points 58 as indicated in FIG. 17.

As such, during movement of the slide 22 relative to the barrel 31, as during chambering of a cartridge within the barrel, upon the barrel 31 returning to its final position relative the slide 22, the barrel 31 is consistently and repeatably positioned at the same axial and vertical position relative the slide 22. Due to this repeatability, accuracy and discharge of the pistol 10 is effectuated merely by proper adjustment of the sight system of the pistol 10.

In FIGS. 19 through 23, the improved sight system of the present invention is depicted. As will be recognized, the sight system comprises a rear sight assembly 18 disposed within a recess 128 formed on the rear end of the slide 22 and a front sight 20 disposed on the opposite or front end of the slide 22 as best seen in FIGS. 1 and 2.

Referring now to FIGS. 19 through 21, the square inlay rear sight 18 of the present invention is depicted. One square inlay 76 is formed upon either side of the sight groove 78. The rear sight 18 is adjusted for elevation by turning elevation adjustment screw 80 to cause the rear sight 18 to pivot about windage adjustment screw 82 against the biasing of rear sight spring 84. Windage adjustment screw 82 secures rear sight 18 within recess 128 formed in slide 22.

Windage is adjusted by turning windage adjustment screw assembly 82 from the right side. Windage adjustment screw assembly 82 is comprised of screw 83 and slotted nut 85 such that a screwdriver can engage the windage adjustment screw assembly 82.

First ball detent 86 is urged outward by spring 87 to engage recesses 88 formed within the rear sight 18 and locks elevation screw 80 in position. A similar ball detent 90 is urged outward by spring 91 and is received by similar recesses 92 to lock windage screw 82 in position.

As shown in FIG. 21, the square inlay front sight 20 of the present invention has a single square inlay 84 formed upon its rear surface. The front sight 20 is secured to the slide 22 using two posts 86. The posts 86 are received within complimentary apertures formed within the slide 22 and the posts are peened to form flared ends 87 which secure the posts 86 therein as shown in FIG. 18.

Each square indicia inlay 76 or 84 is preferably formed by first forming a shallow square recess where the inlay is to be located. The recess is then filled with red or white epoxy, enamel, or other durable colored material. Those skilled in the art will recognize that other processes of forming the inlays are likewise suitable. Additionally, those skilled in the art will recognize that the square markings or indicia may simply be affixed upon the sights 18 and 20 as opposed to being inlayed or recessed therein.

Referring now to FIG. 22 and 23, operation of the rear 18 and front 20 sights is depicted. In use, the upper and lower straight edges of the square inlays 76 and 84 are aligned to lie within a pair of straight lines A and B, thus aligning the pistol 10 in elevation. The vertical lines of the square inlays 76 and 84 are aligned such that equal distances C and D are achieved between the front sight inlay 84 and the two rear sight inlays 76. Alignment of the rear 18 and front 20 sights with a bull's-eye 130 is shown in FIG. 23. Such alignment can be rapidly and accurately obtained due to the ease with which straight lines can be visually aligned. It is a relatively simple matter to judge when the upper surfaces, for instance, of each square inlay 76 and 84 form a single straight line A. It is also relatively simple to judge the distances between adjacent inlays such that equal spacing of C and D is achieved.

Rear 76 and front 84 inlays are sized such that they appear approximately equal in linear dimensions to the user. That is, the front square inlay 84 is sized slightly larger than the two rear square inlays 76 so that when viewed in perspective by the user the more distant front square inlay 84 appears approximately equal in size to the closer rear inlays 76. This, of course, is most important when using the square inlays of the present invention upon a rifle wherein the distance between the front and rear sights is substantial.

While squares having four straight edges are depicted for each inlay 76 and 84, those skilled in the art will recognize that only the inboard vertical edges of rear sight inlays 76 and both vertical edges of front sight inlay 84 as well as either the top or bottom horizontal edges of all three inlays 76 and 84 need to be straight. This permits the definition of line A or B and distances C and D.

It is understood that the exemplary firearm described herein and shown in the drawings represents only a presently preferred embodiment of the invention. Indeed, various modifications and additions may be made to such embodiment without departing from the spirit and scope of the invention. For example, the lever of the passive firing pin lock could engage the firing pin in a variety of different ways. Also, various hammer drop mechanism configurations are possible for withdrawing the firing pin prior to actuating the sear and causing the hammer to fall. Additionally, the V-block barrel bushing may be formed as a separate removable element rather than as an integral portion of the slide as described. Additionally, the sight inlay of the present invention need not be square, but rather may use a variety of different shapes which provide straight horizontal and/or vertical-surfaces which may be quickly and accurately aligned. Thus, these and other modifications and additions may be obvious to those skilled in the art and may be implemented to adapt the present invention for use in a variety of different applications.

* * * * *

[US Patent & Trademark Office, Patent Full Text and Image Database]

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United States Patent	*4,726,136*
Dornaus , et al.	February 23, 1988

Firearm safety devices

Abstract

A firearm is provided having a firing pin block which pulls the firing pin away from the hammer independently of the hammer actuator mechanism. A loaded chamber indicator includes a pivoting indicator lever resistant to breakage and jamming. The firearm also has a reversible thumb safety which is readily inserted, releasably retained and fully operational in either side of the firearm. An ambidextrous thumb safety includes two shaft portions each having integral levers and adapted to mate together to form a single shaft. A selective magazine catch is also provided which allows the shooter to select between a magazine catch mode and a magazine free fall mode.

Inventors:	Dornaus; Thomas F. (Bellflower, CA); Dixon; Michael F. (Huntington Beach, CA)
Assignee:	Dornaus & Dixon Enterprises (Huntington Beach, CA)
Appl. No.:	643254
Filed:	August 22, 1984

Current U.S. Class:	42/70.08; 42/7; 42/70.01
Intern'l Class:	F41C 011/02
Field of Search:	42/70.01,70.08

References Cited [Referenced By]

U.S. Patent Documents

580924	Apr., 1897	Browning	42/70.
580926	Apr., 1897	Browning	42/70.
708794	Sep., 1902	Browning	89/145.
747585	Dec., 1903	Browning	42/70.
808003	Dec., 1905	Browning	42/70.
954441	Apr., 1910	Krag	89/138.
962137	Jun., 1910	Gates	89/196.
984519	Feb., 1911	Browning	89/145.
989432	Apr., 1911	Schmeisser	89/163.
1028032	May., 1912	Krag	89/145.
1105404	Jul., 1914	Loiselet	89/196.
1181416	May., 1916	Wesson	89/145.
1618510	Feb., 1927	Browning	89/163.
2846925	Aug., 1958	Norman	89/145.
3110223	Nov., 1963	Schlappich	89/196.
4021955	May., 1977	Curtis	42/70.
4031808	Jun., 1978	Raville	89/163.
4141166	Feb., 1979	Schultz	42/70.
Foreign Patent Documents
146359	Jun., 1985	EP	42/70.
3323501	Jan., 1985	DE	42/70.

Primary Examiner: Nelson; Peter A.
Attorney, Agent or Firm: Fischer; Morland C.

Claims

We claim:

1. A firing pin block for a gun having a body and a firing pin for striking a cartridge in the gun, comprising:

a bolt adapted to slide transversely through said body between a "fire" position and a "safety" position, said bolt having a non-circular opening through which the firing pin travels;

wherein the firing pin has a first collar and the bolt opening is constricted at one side so that the outer diameter of the pin collar exceeds the inner diameter of the opening at the constricted side, said collar being located on the pin so that when the bolt is in the safety position, the constricted side of the bolt opening prevents the firing pin collar from passing through the bolt opening and thereby preventing said firing pin from reaching the cartridge.

2. The firing pin block of claim 1 wherein the gun has a hammer for striking the firing pin at one end of the pin and the firing pin further has a second collar spaced from the first collar and the bolt has a camming surface shaped and positioned to engage the second firing pin collar and move the firing pin away from the hammer as the bolt is moved from the fire position to the safety position.

3. The firing pin block of claim 2 wherein the gun has a hammer striking surface which defines a hole through which said one end of the firing pin protrudes to be struck by the hammer, said second collar and camming surface being shaped so as to withdraw said one end of the firing pin below the surface of the gun hammer striking surface to prevent the hammer from reaching said one end of the firing pin.

4. The firing pin block of claim 1 further comprising a detent wherein the bolt defines a pair of depressions spaced on the bolt so that the detent releasably engages the first and second depressions to releasably hold the bolt in the fire and safety positions, respectively.

5. In a gun having a spring-loaded hammer, a trigger and a sear cooperating with the trigger to releasably support the hammer until the trigger is pulled, the improvement comprising:

a safety having a shaft extending transversely through the gun, said shaft comprising two axially aligned shaft portions, each shaft portion having an end shaped substantially as a half cylinder and adapted to mate with the other half cylindrically shaped shaft portion when assembled to form a complete cylinder, each shaft portion having an integral manually actuable lever at the other end of the shaft portion for pivoting the safety shaft when assembled between a "fire" position and a "safety" position, and at least one of said shaft portions having means for engaging the sear to prevent release of the support of the hammer when the safety shaft is in the safety position.

6. The gun of claim 5 wherein each half cylindrically shaped end of the shaft portions defines a notch positioned to align with the notch of the other shaft portion when assembled, the gun further comprising retainer means for simultaneously engaging both shaft portion notches to retain the shaft portions together.

7. The gun of claim 6 further comprising a sear housing for pivotally supporting the sear and the safety shaft, and a spring having a leg for biasing the sear in the hammer support position,

wherein the retainer means comprises a slot defined by the sear housing adjacent the safety shaft portion notches and further comprises the spring leg being carried in the sear housing slot and the shaft portion notches.

8. The gun of claim 5 wherein the shaft is pivotal between a second "fire" position and a second "safety" position by the shaft levers when the transverse position of the shaft is reversed, and the gun further comprises a second means on at least one of the shaft portions for engaging the sear to prevent release of the support of the hammer when the safety shaft is in the second safety position.

9. In a gun having a spring-loaded hammer, a trigger, and a sear cooperating with the trigger to releasably support the hammer until the trigger is pulled, the improvement comprising:

a reversible safety comprising a shaft having a manually actuable lever at one end and a free end adapted to be inserted transversely through the gun selectively from either side of the gun, said shaft defining a first transverse position when the free end is inserted from one side and defining a second transverse position when the shaft free end is inserted from the other side of the gun, said lever for pivoting the shaft between a first "fire" position and a first "safety" position when the shaft is in the first transverse position, said lever further for pivoting the shaft between a second "fire" position and a second "safety" position when the shaft is in the second transverse position, said shaft having means for engaging the sear to prevent release of the hammer when the shaft is in either of said first or second safety positions associated with said first and second transverse positions, respectively.

10. The gun of claim 9 wherein the shaft engagement means comprises a pair of projecting members extending in substantially opposite directions, each shaft projecting member for engaging the sear when the shaft is in one of said safety positions associated with said first and second transverse positions.

11. The gun of claim 10 wherein the sear also has a pair of projecting members, each sear projecting member being positioned to be engaged by one of said shaft projecting members when the shaft is in a safety position associated with that shaft projecting member.

12. The gun of claim 9 further comprising means for releasably retaining the shaft when the shaft is in either of the first or second transverse positions.

13. The gun of claim 12 wherein the gun has a sear housing for pivotally supporting the sear and the shaft and a spring having a leg for biasing the sear in the hammer support position, wherein the retaining means comprises a pair of notches defined by the shaft and a slot defined by the sear housing, said notches being positioned on the shaft so that the housing slot is aligned with one shaft notch when the shaft is in the first transverse position and is aligned with other shaft notch when the shaft is in the second transverse position, said retaining means further comprising said leg of the spring carried within the sear housing slot and one of said shaft notches wherein the shaft may be released by lifting the spring leg out of the associated shaft notch.

14. In a gun having a firing pin which has one end protruding beyond a hammer striking surface and adapted to be struck at said one end causing the other end of the pin to strike a cartridge within the gun, the improvement comprising:

means for withdrawing and releasably holding the firing pin below the hammer striking surface to prevent the hammer from reaching the firing pin.

15. The gun of claim 14 wherein the withdrawing and holding means comprises a movable member and a camming surface carried on one of said member or firing pin and adapted to engage the other of said member or pin to withdraw the pin.

16. The gun of claim 14, said improvement further comprising a firing pin block bolt having relatively large and small diameter openings formed therein, said bolt being movable to either a free position for bringing said relatively large diameter opening into alignment with the longitudinal axis of said firing pin or to a safety position for bringing said relatively small diameter opening into alignment with the longitudinal axis of said firing pin, said relatively large and small diameter openings being particularly sized relative to said firing pin, so that when said bolt is moved to the fire position, said firing pin may pass through the relatively large diameter opening therein to strike said cartridge, and when said bolt is in the safety position, said firing pin cannot pass through the relatively small diameter opening therein, whereby to prevent said firing pin from reaching said cartridge.

17. The gun of claim 16, wherein said firing pin has a collar formed therearound and said relatively small diameter opening has a peripheral ledge, said collar being engaged by and seated against said ledge to block the passage of said firing pin through said small diameter opening and toward said cartridge when said firing pin block bolt is moved to the safety position and said firing pin is aligned with said small diameter opening.

18. In a gun having a spring-loaded hammer, a trigger and a sear cooperating with the trigger to releasably support the hammer until the trigger is pulled, the improvement comprising:

safety means including a shaft having a manually actuable lever at one end and an opposite free end adapted to be inserted transversely through the gun from a side thereof, said lever rotating the shaft between fire and safety positions; and

said shaft having means to engage the sear and thereby prevent a release of the hammer and a discharge of the gun when said lever rotates said shaft to the safety position.

19. The gun of claim 18, wherein said shaft engagement means comprises at least one member projecting outwardly from said shaft, said outwardly projecting member being rotated with said shaft to engage said sear and thereby prevent a release of the hammer and a discharge of the gun when said lever rotates said shaft to the safety position, and the outwardly projecting member being rotated out of engagement with said sear to release the hammer and permit a discharge of the gun when said lever rotates said shaft to the fire position.

20. The gun of claim 19, wherein said sear also has at least one outwardly projecting member, said sear projecting member positioned so as to be engaged by said shaft projecting member when said lever rotates said shaft to the safety position.

21. The gun of claim 18, further comprising a sear housing to pivotally receive said sear therewithin and means to releasably retain said shaft within said sear housing, said retaining means comprising a sear spring having first and second projecting ends, a first projecting end of said sear spring engaging a notch in said shaft and an aligned slot in said sear housing, and the second projecting end of said spring engaging said sear to bias said sear in a hammer supporting position.

22. The gun of claim 21, wherein said sear spring is a coil spring, the coil of said spring being carried by a pin which pivotally supports the sear within said sear housing.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to firearms, and more particularly, to devices for facilitating the safe handling of firearms.

2. Description of the Prior Art

Automatic and semiautomatic firearms or guns such as magazine loaded rifles and handguns typically have a firing pin which when struck by the hammer of the firearm, is driven forward striking and discharging the cartridge held within the firing chamber of the firearm. Several devices have been proposed to selectively block the firing pin to prevent the firearm from being accidentally fired. For example, in a semiautomatic handgun, these devices (often referred to as "firing pin blocks") are typically mounted within the frame of the gun and have mechanical linkages to the firing pin itself which is usually carried in the slide of the gun. These previous firing pin blocks have tended to be relatively complicated and, because of their location adjacent the handgrip of the frame, are susceptible to being accidentally disengaged by the shooter. Moreover, many such firing pin block devices do not constantly block the firing pin when activated, but instead cooperate with other mechanisms such as the hammer actuator mechanism to only block the firing pin in certain hammer positions.

Other safety devices include loaded chamber indicators which indicate to the shooter whether a cartridge is seated in the firing chamber in position for firing. Many previous loaded chamber indicators have included a spring-loaded pin which has one end positioned relative to the firing chamber such that a cartridge loaded in the chamber engages and pushes the indicator pin outward. This outward movement of the pin usually causes a portion of the pin to protrude beyond the exterior of the gun providing an indication that a cartridge is loaded in the chamber. These pins are often relatively small in diameter and can be susceptible to breakage. Moreover, dirt lodged against the pin can immobilize the pin causing the gun to jam.

Still another safety device is the thumb safety so called because it is typically actuated by the shooter's thumb. The thumb safety usually locks the gun so that the hammer is prevented from falling even though the trigger is pulled. To activate the safety, most thumb safeties have an exterior lever on the left-hand side of the gun positioned adjacent the thumb of a right-handed user. Pivoting the lever causes the safety to engage and "lock" the hammer actuator.

To accommodate left-handed users, some thumb safeties allow a second lever to be placed on the right-hand side of the gun to form an "ambidextrous" thumb safety. This second lever is often attached to a shaft extending transversely through the gun. One problem experienced with ambidextrous thumb safeties of this type is that the second thumb lever can sometimes work loose from the shaft of the safety so that positive engagement of the safety is not always assured.

Many left-handed shooters prefer to have only the single thumb safety lever on the right-hand side of the gun so that the lever on the left-hand side of the gun is eliminated. However, many guns require such a thumb safety for "lefties" to be custom crafted by a skilled gunsmith.

Other devices for safe handling of firearms relate to the loading and unloading of ammunition. In one type of gun, the cartridges to be fired by the gun are carried in a removable magazine which is inserted into a portion of the frame of the gun often referred to as the "magazine well." In many magazine-type guns, the magazine falls freely from the magazine well under the influence of gravity once released. The released magazine will fall to the ground unless caught by the shooter placing his hand beneath the gun. This is a desirable feature under certain circumstances but requires additional care on the part of the shooter. Other magazine-type guns have a catch mechanism which only allows the magazine to partially drop from the magazine well once released. The shooter may then manually withdraw the magazine the rest of the way from the well. However, it is not believed that there is presently available a magazine-type gun in which the user may select between allowing the magazine to drop freely and allowing the magazine to only partially drop from the well to prevent complete release of the magazine.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a gun or firearm having safety devices obviating for practical purposes, the above-mentioned limitations.

It is a further object of the present invention to provide a firing pin block which is located on the firearm in such a position so as to minimize accidental release of the firing pin block.

It is another object of the present invention to provide a relatively simple yet effective firing pin block.

It is a further object of the present invention to provide a firing pin block which is independent of the trigger mechanism of the gun.

It is another object of the present invention to provide a loaded chamber indicator which is less susceptible to breakage and to jamming the gun.

It is still another object of the present invention to provide a more reliable ambidextrous thumb safety which is easily disassembled from the gun.

It is a further object of the present invention to provide a reversible thumb safety which is easily installed on either side of the gun without the aid of a gunsmith.

In one aspect of the present invention, a firing pin block is provided which pulls the firing pin towards the muzzle and below the hammer striking surface of the gun to prevent the hammer from being able to reach the firing pin. In the illustrated embodiment, the firing pin block includes a bolt mounted transversely through the slide and adapted to engage and disengage the firing pin as the bolt is moved between "safety" and "fire" positions, respectively.

In another aspect of the present invention, a loaded chamber indicator includes a lever pivoted at one end to the firearm with the free end of the lever positioned adjacent the opening of the firing chamber. A cartridge loaded in the chamber causes the indicator lever to pivot outward providing an indication of the chamber being loaded.

In still another aspect of the present invention, an ambidextrous thumb safety includes a shaft comprising two shaft portions. Each shaft portion has an integral thumb lever at one end and is shaped substantially as a half cylinder at the other end. The two shaft portions are adapted to mate together to form a single shaft.

In an additional aspect of the present invention, a fully reversible thumb safety is provided. In the illustrated embodiment, the thumb safety has a shaft and an integral thumb lever wherein the shaft is readily insertable into either side of the firearm. The shaft has projecting members on either side of the shaft to allow the thumb safety to engage the hammer actuator mechanism regardless of which side of the firearm the thumb safety is installed.

In a further aspect of the present invention, a selective magazine catch is provided in which the magazine may either fall freely or catch in the magazine well after falling a predetermined distance, as desired by the shooter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a semiautomatic handgun in accordance with a preferred embodiment of the present invention;

FIG. 2 is an exploded perspective view of the slide assembly of the handgun of FIG. 1 illustrating a loaded chamber indicator and a firing pin block in accordance with a preferred embodiment of the present invention;

FIG. 3 is an assembled cross-sectional view of the slide assembly of FIG. 2 showing the firing pin block in the fire position and the loaded chamber indicator with a cartridge loaded into the chamber;

FIG. 4 is a front view of the bolt of the firing pin block viewed along the line 4--4 of FIG. 3;

FIG. 5 is an assembled cross-sectional view of the slide assembly of FIG. 1 showing the fire pin block in the safety position and the loaded chamber indicator without a cartridge in the chamber;

FIG. 6 is a rear view of the bolt of FIG. 1 viewed along the line 6--6 of FIG. 3;

FIG. 7 is a partial perspective view of the assembled loaded chamber indicator of FIG. 2;

FIG. 8 is an exploded perspective view of the frame of the handgun of FIG. 1 illustrating a reversible thumb safety and selective magazine catch in accordance with a preferred embodiment of the present invention;

FIG. 9 is a perspective view of the selective magazine catch of FIG. 8;

FIG. 10 is a cross-sectional view of the selective magazine catch of FIG. 9 viewed along the line 10--10;

FIG. 11 is a side view of the selected magazine catch of FIG. 9 in the catch position showing a magazine partially dropped out;

FIG. 12 is a cross-sectional view of the selective magazine catch of FIG. 11 viewed along the line 11--11;

FIG. 13 is an exploded perspective view of the reversible thumb safety of FIG. 8;

FIG. 14 is a top view of the assembled frame of FIG. 8 showing the safety in the fire position with the lever on the left side of the gun;

FIG. 15 is a cross-sectional view of the safety of FIG. 14 viewed along the line 15--15;

FIG. 16 is a cross-sectional view of the safety of FIG. 14 viewed along the line 16--16;

FIG. 17 is a cross-sectional view of the safety of FIG. 14 showing the safety in the safety position;

FIG. 18 is a top view of the assembled frame of FIG. 8 showing the safety in the fire position with the lever on the right side of the frame;

FIG. 19 is an exploded perspective view of an ambidextrous thumb safety lever in accordance with a preferred embodiment of the present invention; and

FIG. 20 is a perspective view of the assembled ambidextrous thumb safety lever of FIG. 18.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a semiautomatic handgun 10 (hereinafter "gun 10") which incorporates the safety features of the present invention. Although the illustrated embodiments of the present invention are described in connection with such a handgun, it is recognized that these safety features may also be utilized in other types of firearms.

The gun 10 has in accordance with one aspect of the present invention, a firing pin block mechanism 12 which may be seen more clearly in FIG. 2 which is an exploded view of the slide assembly 14 of the gun 10. In a manner well understood in the art, the slide assembly 14 moves sharply rearward (as indicated by the arrow 16) after a shot has been fired, to eject the spent cartridge and recock the hammer 18 (FIG. 1). Housed within the slide body 20 of the slide assembly 14 is the firing pin 22 as shown in FIG. 3. The firing pin 22 is carried in a generally cylindrical bore 24 which longitudinally extends from a firing pin retainer plate 26 to the breech face 28 adjacent the end of the barrel 30.

A spring 32 engaging a collar 34 of the firing pin 22 urges the firing pin rearward towards the retainer plate 26. The retainer plate 26 has an aperture 36 which allows the end 38 of the firing pin 22 to protrude beyond the hammer striking surface 40 of the retainer plate 26 until a collar 42 of the firing pin 22 engages the other side 44 of the retainer plate 26. The hammer 18 when released, is driven forward by a spring (not shown) causing the hammer 18 to strike the end 38 of the firing pin 22. This in turn drives the firing pin 22 forward causing the other end 46 of the firing pin to strike the primer of the cartridge 48 loaded within the chamber 50 of the gun 10.

In accordance with the present invention, the firing pin block 12 when engaged, pulls the end 38 of the firing pin 22 below the hammer striking surface 40 of the retainer plate 26 so that the hammer 18 cannot reach the end 38 of the firing pin 22. In addition, as will be more fully described below, the firing pin block 12 also blocks the firing pin 22 from reaching the cartridge 48.

Referring to both FIGS. 2 and 3, the firing pin block 12 includes a bolt 52 which is carried in a generally cylindrical bore 54 extending transversely across the slide body 20 and intersecting the firing pin bore 24. The bolt 52 has a noncircular opening 56 through which the firing pin 22 moves to strike the cartridge 48 if the bolt 52 is in the position illustrated in FIG. 3 and hereinafter referred to as the "fire" position.

The noncircular opening 56 of the bolt 52 may be seen more clearly in FIG. 4 which shows a front view of the bolt 52. As shown therein, the opening 56 is generally "keyhole" in shape and includes a first opening 58 which has an inner diameter exceeding that of a collar 60 (FIG. 3) on the firing pin 22. When the bolt 52 is in the fire position as illustrated in FIG. 3, the opening 58 of the bolt 52 is centered relative to the center axis of the firing pin 22 so that the collar 60 of the firing pin 22 can freely travel through the bolt 52 to strike the cartridge 48.

However, overlapping the opening 58 is a second smaller opening 62 of the bolt. The diameter of the opening 62 is slightly larger than the main shaft 63 of the firing pin 22 but is significantly smaller than the outer diameter of the pin collar 60. When the head 64 of the bolt 52 is pressed inward to the position illustrated in FIG. 5 (hereinafter referred to as the "safety" position), the opening 62 is centered with respect to the center axis of the firing pin 22 so that the collar 60 of the firing pin 22 is prevented from passing through the opening 56 of the bolt 52. The constricted opening 62 has a flat ledge 66 at its periphery to securely seat the collar 60 if the firing pin 22 should move toward the cartridge to effectively block the pin 22.

In addition, the bolt 52 has a camming surface 68 on its rear side adjacent the opening 56, which engages another collar 70 of the firing pin 22 as the bolt 52 is pushed to the safety position of FIG. 5. As best seen in FIG. 6, the camming surface 68 rises from a lower shelf 72 at the periphery of the larger opening 58 to an upper shelf 74 at the periphery of the smaller opening 62. The camming surface 68 is generally cylindrical in shape and is formed by boring the bolt 52 at an angle relative to the central axes of the openings 58 and 62.

Because the upper shelf 74 is closer (FIG. 5) to the muzzle than the lower shelf 72, engagement of the firing pin collar 70 by the camming surface 68 as the bolt 52 is pushed towards the safety position of FIG. 5, pushes the firing pin 22 towards the muzzle and away from the hammer. The displacement between the lower shelf 72 and upper shelf 74 is sufficiently large to move the end 38 of the firing pin 22 completely below the hammer striking surface 40 of the retainer plate 26. Consequently, the hammer cannot reach the firing pin when the bolt 52 is fully in the safety position illustrated in FIG. 5. Furthermore, the ledge 66 (FIG. 4) on the front of the bolt 52 prevents the firing pin 22 from being able to reach the primer of the cartridge within the gun chamber as previously described.

To releasably hold the bolt 52 in the respective fire and safety positions, the bolt 52 has a pair of indentations 83 and 84 on its upper surface 77 and positioned to engage a detent 78 (FIG. 2) biased downward from the top of the slide body 20 by a spring 80. The detent 78 engages the indentation 84 (FIG. 4) when the firing pin block bolt 52 is in the fire position. Depressing the head 64 of the bolt 52 causes the detent 78 to ride up out of the indentation 84 and fall into the other indentation 83 when the bolt 52 is pressed into the safety position. Pressing the opposite head 82 of the bolt 52 returns the bolt to the fire position. The bolt heads 64 and 82 may be marked with suitable indices such as "S" and "F", respectively.

It is seen from the above that the firing pin block 12 provides a simple yet effective mechanism for preventing accidental discharge of the firearm. The firing pin block 12 is independent of all other trigger and safety mechanisms and accordingly is always in action when actuated. Furthermore, because the firing pin block is located completely in the slide assembly 14 and away from the hand grip 156 (FIG. 1), the likelihood of accidental disengagement of the firing pin block is correspondingly reduced.

FIG. 2 also shows a loaded chamber indicator 100 in accordance with a preferred embodiment of the present invention. The loaded chamber indicator 100, as its name suggests, indicates to the shooter whether a cartridge is loaded in the firing chamber of the pistol when the slide assembly 14 is in the fully forward position illustrated in FIG. 1.

In accordance with the present invention, the loaded chamber indicator 100 includes an indicator lever 102 which is pivotally coupled to the slide body 20 of the slide assembly 14. When assembled, the lever 102 is carried in a flat depression 104 of the cartridge extractor lever 106. The extractor lever 106 and indicator lever 102 pivot around a common pivot pin 112 within an extractor slot 114 (FIG. 7). As best seen in FIGS. 3 and 7, the extractor slot is provided on the right side of the slide body 20 and extends rearward from the breech face 28.

The extractor lever 106 has a small hooked portion 108 which engages the base (FIG. 3) of the cartridge loaded in the firing chamber. As the slide assembly 14 retracts after the cartridge has been fired, the extractor lever 106 hooked to the base of the cartridge pulls the expended casing from the firing chamber, to be ejected out through ejection port 110 (FIG. 2) of the slide body 20.

In the illustrated embodiment, the extractor lever 106 has an aperture 116 in the exterior face portion 118, which communicates with the flat depression 104. The extractor lever 106 further has a cylindrical depression 120 which carries a spring 122 biasing the indicator lever 102 in a counterclockwise direction as viewed in FIG. 3. One end of the spring 122 seats in a notch 124 of the indicator lever 102 and the other end seats within a depression 123 on the inner side of the exterior face portion 118 of the extractor lever 106. A second spring 126 also biases the extractor lever 106 in a counterclockwise direction.

When a cartridge is loaded in the firing chamber 50, the exterior of the cartridge casing engages an engagement surface 128 on the inner side of the indicator lever 102, thereby pushing the indicator lever 102 outward in a clockwise direction to the "chamber loaded" position of FIGS. 3 and 7. Thus, when seated, the cartridge 48 causes protrusion portion 130 on the other side of the indicator lever 102 to protrude approximately 1/16th of an inch beyond the exterior of the extractor face portion 118 through the aperture 116 of the extractor lever 106. The protrusion portion 130 provides a visual and tactile indication that a cartridge is loaded in the firing chamber. The tip of the protrusion portion 130 may be painted a bright color such as red to further enhance the visibility of that portion of the lever.

On the other hand, if there is no cartridge in the firing chamber, the indicator lever 102 is pivoted in a counterclockwise direction by the spring 122 towards the interior of the firing chamber to the "chamber empty" position of FIG. 5. Consequently, the tip of the protruding portion 130 of the indicator lever 102 is moved inward (FIG. 5) so that it is flush with (or somewhat interior of) the exterior face portion 118 of the extractor lever 106. This indicates to the shooter that the firing chamber is empty.

Because the indicator lever 102 is carried in a depression of the extractor lever 106, a separate slot or aperture need not be machined into the slide body 20 for the indicator lever 102. Instead, the indicator lever 102 utilizes the slot 114 already provided for the extractor lever 106. This saves an additional machining step and reduces the number of access points for dirt to enter the interior of the gun. Furthermore, the extractor lever 106 and the upper surface of the slot 114 protect the lever 102. Thus, the lever arrangement of the indicator 100 has been found to be less susceptible to jamming and breakage than many previous loaded chamber indicators.

FIG. 8 shows an exploded view of a selective magazine catch assembly 150 in accordance with a preferred embodiment of the present invention. The magazine 151 (FIG. 9) for housing the cartridges is inserted through an aperture 152 in the frame 158 to the magazine well 154 defined by the handgrip 156 of the handgun frame 158. The magazine when fully inserted into the magazine well 154, is releasably retained within the well by a suitable magazine retainer mechanism 160. The retainer mechanism 160 includes a release button 162 which when depressed, causes the mechanism 160 to release the magazine from the magazine well 154.

In accordance with the present invention, the selective magazine catch 150 allows the shooter to select either of two magazine removal modes. In one mode, the magazine 151 is allowed to fall freely from the magazine well 154 when the release button 162 is depressed. Alternatively, in the second mode, the magazine catch 150 catches the magazine after it has fallen a predetermined distance. The shooter may then manually extract the magazine the rest of the way from the magazine well 154.

Referring to FIGS. 8-10, the selective magazine catch 150 includes an engagement member 164 having a rounded engagement surface 166 at one end. The engagement member 164 further has a generally cylindrical bore 168 adapted to receive one end of a generally U-shaped spring 170 having legs 171 and 180. As best seen in FIG. 10, the engagement member 164 is carried in a cylindrical bore 172 at one side 190 of the base 174 of the frame hand grip 156. The spring 170 is mounted on the base 174 as shown in FIGS. 9 and 10 with the cross portion 176 between the spring legs 171 and 180 seated in a notch 178 in the handgrip 156. The other leg 180 of the spring 170 has a hooked end 182 which is seated in a bore 184 on the opposite side 185 of the base 174. The spring 170 urges the engagement member inward toward the magazine well.

The magazine catch 150 further includes a cam lever 188 which is placed between the spring leg 171 and the base side portion 190. The cam lever 188 is adapted to pivot about a round protrusion 192 (FIG. 8) which is inserted into a bore 194 in the base side portion 190.

In order to move the engagement member 164 between a "withdrawn" position (FIGS. 9 and 10) and an "engagement" position (FIGS. 11 and 12 respectively), the cam lever 188 has a camming surface 198 on its exterior side for engaging the spring leg 171. The withdrawn and engagement positions of the member 164 correspond to the free fall and catch modes, respectively.

The camming surface 198 includes a pair of generally trough-shaped depressions 200 and 202 positioned on the cam lever 188 to alternately receive the spring leg 171 when the cam lever 188 is in the positions of FIGS. 11 and 9, respectively. The cam lever 188 further has a second protruding member 204 axially aligned with the protruding member 192 on the other side of the level 188. The member 204 defines a slot 206 to provide a manually actuable control member for pivoting the cam lever 188 between the positions illustrated in FIGS. 9 and 11. A screw driver is recommended to actuate the control member 204.

The depression 202 is machined to space the spring leg 171 from the base side portion 190 so as to position the engagement member 164 in the "withdrawn" position illustrated in FIG. 10. As shown therein, the engagement member 164 does not protrude beyond the inner face 206 of the base side portion 190. Consequently, the engagement member 164 does not interfere with the free fall of the magazine 151 from the magazine well 154 when released by the mechanism 160.

Alternatively, when the cam lever 188 is pivoted so that the spring leg 171 falls into the other depression 200 as shown in FIG. 11, because the depression 200 is deeper than the depression 202, the spring leg 171 is spaced closer to the base side portion 190. As a result, the engagement member 164 protrudes beyond the inner face 206 under the urging of the spring 170. As shown in FIG. 9, the magazine 151 has an indentation 210 which extends a predetermined distance from the base of the magazine. When the magazine is released, the engagement member 164 engages the end 211 of the indentation 210 after the magazine has fallen the predetermined distance thereby catching the magazine. The shooter may then manually extract the magazine the rest of the way from the magazine well 154 causing the engagement member 164 to be pushed back into the bore 172 against the spring 170.

It is evident from the above that the magazine catch 150 allows the shooter to select between either the magazine freefall mode (FIGS. 9 and 10) or the magazine catch mode (FIGS. 11 and 12). To facilitate the movement of the cam lever 188 between the two positions of FIGS. 9 and 11, the camming surface 198 between the troughs 200 and 202 may be rounded. The magazine catch 150 is disposed in depressions 179 and 181 at the frame base 174 to allow the handgrips stocks 380 and 382 to be placed over the magazine catch 150 with the control member 204 accessible through an aperture in the stock 380 as shown in FIG. 1.

FIG. 8 also shows a thumb safety 250 which, in accordance with the present invention, is fully reversible so that the shaft 252 of the thumb safety 250 may be inserted into either side of the firearm frame 158. In this manner, the thumb safety 250 is conveniently usable by either right or left-handed shooters.

The shaft 252 of the safety 250 has an integral lever 258 at one end, by which the shaft 252 may be manually pivoted between a "fire" position and a "safety" position discussed below. The free end 259 of the shaft 252 is inserted transversely across the frame 158 through one of the apertures 254 or 256 of the frame 158. When the shaft 252 is inserted through the left-hand aperture 254 so that the lever 258 is also on the left side of the frame 158, the shaft 252 defines a "left-handed" transverse position, for a right handed shooter. Alternatively, when the shaft 252 is inserted through the right-hand aperture 256 so that the lever 258 is also on the right side of the frame 158, the shaft 252 defines a "right-handed" transverse position, for a left handed shooter.

Each shaft transverse position has associated therewith a "fire" position and a "safety" position in which, in the illustrated embodiment, the fire positions correspond to the lever being oriented generally horizontal while the safety positions correspond to the lever being pivoted upward a predetermined angular distance. In either transverse position of the shaft 252, the lever 258 is pointed generally forward so that the shaft 252 is generally upside down in one transverse position relative to the other transverse position. A suitable detent mechanism 159 cooperates with depressions 261 on both sides of the frame to releasably hold the lever 258 in the fire and safety positions.

The handgun 10 of the illustrated embodiment is of a type in which the hammer actuator mechanism 260 includes a sear 262 which has a rearward pointing ledge 264 which releasably supports the spring-loaded hammer 18 in the cocked position. When the trigger 266 is pulled, a trigger bar 268 coupled to the trigger 266 by a pivot pin 270, is pushed rearward. The end 272 of the trigger bar 268 engages a pair of downward extending levers 274 of the sear 262 causing the sear 262 to pivot in a counterclockwise direction (as viewed in FIG. 8) within the sear housing 276. This pivotal movement of the sear 262 moves the sear ledge 264 out of the way of the hammer 18 allowing the hammer to fall and strike the firing pin 22 (FIG. 2). However, as explained below, when the safety shaft 252 is in either of the safety positions, the sear 262 is prevented from pivoting out of the way of the hammer 18 thereby preventing discharge of the gun.

As shown in FIG. 13, the safety shaft 252 has a pair of vertical projecting members 280 and 282 extending in opposite directions. When assembled in the sear housing 276, the shaft 252 is pivotally carried within a cylindrical bore 284 (FIG. 14) extending transversely through the sear housing 276. The sear housing 276 has a left-hand slot 286 adjacent the bore 284 which allows the projecting members 280 and 282 to pivot within the sear housing 276.

In the fire positions, the projecting members 280 and 282 are oriented vertically so that the sear 262 can pivot unhindered by the shaft projecting member. Thus, as shown in FIG. 16, with the shaft 252 inserted through the frame lefthand aperture 254 so that the safety lever 258 is on the left-hand side of the gun, the projecting member 280 is clear of the sear 262 when the lever 258 is oriented horizontally corresponding to the fire position. However, should the safety lever 258 be pivoted in a clockwise direction (as viewed in FIG. 17), approximately 20 degrees to the safety position, the shaft projecting member 280 will be pivoted rearward towards the sear 262. In this position, if the trigger 266 is pulled, the shaft projecting member 280 will engage an opposing projecting member 288 of the sear 262, thereby preventing the sear 262 from pivoting and the gun from being discharged.

FIG. 18 shows the safety shaft 252 inserted through the right-hand frame aperture 256. The sear housing 276 has a second (right-hand) slot 290 similar to the left-hand slot 286 on the other side of the sear housing to accommodate the pivoting of the projecting members 280 and 282. With the safety shaft 252 in the right-hand transverse position shown in FIG. 18, the other shaft projecting member 282 is now projecting upward from the shaft. When the safety lever 258 is pivoted to the safety position, the projecting member 282 is moved below an opposing projecting member 292 (FIG. 13) similar to the projecting member 288 on the other side of the sear 262. Should the trigger be pulled with the shaft 252 in the safety position, the projecting member 282 will engage the opposing projecting member 292 of the sear preventing the sear from releasing the hammer. Thus, it is seen that the projecting members 280 and 282 allow the thumb safety 250 to be fully operational whether installed on the left-hand or the right-hand side of the frame.

The sear housing 276 has longitudinal apertures 300 on either side of the sear housing 276 to accommodate the shaft projecting members 280 and 282 as they are inserted into the slots 286 or 290. To releasably retain the shaft 252 in the left-hand transverse position within the sear housing 276, the shaft 252 has a first notch 302 (FIG. 13) positioned on the shaft so that it is aligned with a slot 304 (FIGS. 14 and 15) in the sear housing adjacent the bore 284 when the shaft 252 is inserted into the sear housing 276 in the left-hand transverse position. Engaging both the shaft notch 302 and the housing slot 304 is the leg 306 of a sear spring 308 which biases the sear 262 in a counterclockwise direction as viewed in FIG. 15. The coil of the sear spring 308 is carried on a pin 310 which pivotally supports the sear 262 within the sear housing 276. The other end 312 of the sear spring 308 engages the sear 262 to bias it in the hammer support position.

With the sear spring leg 306 disposed on the aligned shaft notch 302 and housing slot 304, the shaft 252 is locked against substantial transverse motion but the sear spring leg 306 does not prevent the pivotal movement between the safety and fire positions previously described. To release the shaft 252 to allow the shaft to be inserted into the other side of the gun frame, one merely pries the spring leg 306 upward out of the shaft notch 302 freeing the shaft 252 to be pulled out. The shaft 252 has a second notch 320 (FIG. 13) positioned to align with the housing slot 304 when the shaft 252 is inserted from the other side as illustrated in FIG. 18.

Since the spring leg 306 is biased downward, the end of the shaft 252 has a camming surface 322 (FIG. 13) which pries the spring leg 306 upward as the shaft is inserted through the sear housing bore 284 with the lever 258 oriented vertically. Once the spring leg 306 is pried upward, the safety lever 258 may be pivoted forward which further pries the spring leg 306 upward to allow the shaft 252 to be inserted the rest of the way into the sear housing 276. When the shaft notch 302 (or 320) reaches the housing slot 304, the sear spring leg 306 snaps down into the notch retaining the shaft 252 within the sear housing.

Concentric with the shaft 252 is a circular shoulder 324 (FIG. 13) on the lever 258, which is adapted to slidingly mate with the walls of the particular aperture 254 or 256 through which the shaft 252 is inserted. The safety 250 further includes a bushing 330 which is inserted into either of the apertures 254 or 256. The free end of the shaft 252 is inserted into an axially, aligned bore 338 of the bushing 330. The bushing 330 has a shelf member 332 which engages opposing flange members 334 and 336 to support the sear housing.

Thus, to reverse the thumb safety, the safety shaft 252 is released by prying up the spring by 306 and removing the shaft 252. This allows the sear housing to be removed and reinstalled with the bushing 330 on the other side of the frame. The safety shaft is then reinserted from the other side until the spring retainer again locks the shaft into place. It is seen from the above that the thumb safety 250 is capable of being easily installed on the either side of the gun by the typical user without the aid of a gunsmith.

FIG. 19 shows an exploded view of alternative embodiment of the safety shaft of FIGS. 13-17. The safety shaft 340 of FIG. 18 is part of an ambidextrous thumb safety and includes two shaft portions 342 and 344. The shaft portion 342 has one end 346 which is shaped substantially as a half cylinder and is adapted to mate with a similarly shaped end 348 of the other shaft portion 344. When mated, the shaft portions 342 and 344 form a complete shaft 349 as shown in FIG. 19. Each shaft portion has an integrally formed lever 350 similar to the shaft lever 248 of FIG. 12.

As shown in FIGS. 18 and 19, the shaft portion 342 has a notch 352 which is positioned to align with a notch 354 of the other shaft portion 344 when the shaft portions 342 and 344 are mated together. The notches 352 and 354 of the two shaft portions form a single notch 355 similar to the notch 302 of the previous embodiment so that the sear spring leg 306 cooperates with both of the notches 352 and 354 and the sear housing notch 304 to releasably retain both shaft portions 342 and 344 in the sear housing 276. A second pair of notches 356 and 358 on the other sides of the shaft portions 342 and 344, respectively, form a second complete notch 360 similar to the notch 320 of FIG. 12 to allow the shaft portions to be reversed so that it doesn't matter which shaft portion is inserted through which frame aperture.

It has been found that the split shaft safety 340 with integral shaft levers 350 provides a stronger and more reliable ambidextrous thumb safety mechanism than many previous ambidextrous safeties. Furthermore, the above described spring and notch arrangement allows for the rapid release and reinstallation of the shaft portions.

It will, of course, be understood that modifications of the present invention, in its various aspects will be apparent to those skilled in the art, some being apparent only after study and others being merely matters of routine mechanical design. For example, the above-described safety devices can be utilized on other types of firearms. Other embodiments are possible with the specific designs dependent on the particular application. As such, the scope of the invention should not be limited by the particular embodiments herein described which should be defined only by the appended claims and equivalents thereof.

* * * * *

[US Patent & Trademark Office, Patent Full Text and Image Database]

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United States Patent	*5,245,776*
Dornaus	September 21, 1993

Firearm having improved safety and accuracy features

Abstract

An improved firearm having a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays is disclosed. The passive firing pin block prevents accidental discharge when the gun is dropped. The hammer drop mechanism permits the hammer to be safely lowered when a cartridge is present in the chamber without actuating the trigger. The V-block type barrel bushing accurately repositions the forward end of the barrel relative to the sights to provide maximum accuracy. The square sight inlays allow the user to quickly and precisely aim the firearm.

Inventors:	Dornaus; Thomas F. (Norwalk, CA)
Assignee:	Voit; Richard A. (Balboa, CA)
Appl. No.:	537064
Filed:	June 12, 1990

Current U.S. Class:	42/70.08; 42/144
Intern'l Class:	F41A 017/64
Field of Search:	42/70.08 89/148

References Cited [Referenced By]

U.S. Patent Documents

891510	Jun., 1908	Tansley	42/70.
917723	Apr., 1909	Ehbets	42/70.
2169084	Apr., 1937	Swartz	42/70.
2846925	Aug., 1958	Norman	89/148.
3371441	May., 1968	Walther	42/70.
3724113	Apr., 1973	Ludwig	42/70.
3830002	Aug., 1974	Volkmar	42/70.
3942278	Mar., 1976	Schaller et al.	42/70.
4021955	May., 1977	Curtis	42/70.
4090316	May., 1978	Volkmar	42/70.
4282795	Aug., 1981	Beretta	89/148.
4306487	Dec., 1981	Beretta	89/148.
4313274	Feb., 1982	Ludwig et al.	42/70.
4395839	Aug., 1983	Eder	42/70.
4454673	Jun., 1984	Meidel	42/70.
4555861	Dec., 1985	Khoury	42/70.
4575963	Mar., 1986	Ruger et al.	42/70.
4590697	May., 1986	Ruger et al.	42/70.
4726136	Feb., 1988	Dornaus et al.	42/70.
4768302	Sep., 1988	Beretta	42/70.
Foreign Patent Documents
200967	Dec., 1958	AT	42/70.
660046	Oct., 1951	GB	42/70.

Other References

"Astra A-80 Pistol", American Rifleman, vol. 129, No. 9.
"This DA Auto Handles Five Calibers", Shooting Times, May 1974.

Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Stetina & Brunda

Claims

What is claimed is:

1. A hammer drop mechanism for a firearm having a firing pin which has one end protruding beyond a hammer striking surface and adapted to be struck by a hammer, and having a sear for releasably holding the hammer in a cocked position, the hammer drop mechanism comprising:

(a) a first means for withdrawing and releasably holding the firing pin below the hammer striking surface to prevent the hammer from striking the firing pin;

(b) a second means for causing the hammer to drop to the hammer striking surface after the firing pin has been withdrawn below the hammer striking surface;

(c) wherein said first means and said second means are commonly actuated;

(d) said means for withdrawing and releasably holding the firing pin comprises a rotatably member having a firing pin cam formed thereupon and a camming surface formed upon the firing pin such that rotation of the rotatable member causes the firing pin cam to engage the camming surface to withdraw the firing pin; and

(e) said means for causing the hammer to drop comprises a hammer drop cam formed upon the rotatable member, a pin translatable by the camming action of the hammer drop cam, and a sear responsive to the translation of the pin to cause the hammer to drop when the rotating member is rotated.

2. A hammer drop mechanism as recited in claim 1 further comprising a lever, actuatable by a user, for rotating the rotatable member.

3. A hammer drop mechanism for a firearm, the mechanism comprising:

(a) a shaft;

(b) a first firing pin cam formed upon said shaft;

(c) a hammer drop cam formed upon said shaft;

(d) a lever formed upon one end of said shaft such that said shaft may be manually rotated;

(e) a firing pin disposed proximate said shaft;

(f) a hammer disposed proximate said firing pin for striking said firing pin, said hammer having cocked and decocked positions;

(g) a first camming surface formed upon said firing pin such that rotation of said shaft causes said first firing pin cam to engage said first camming surface to reposition said firing pin such that said hammer is prevented from striking said firing pin;

(h) a sear engageable to said hammer for maintaining said hammer in a cocked position;

(i) a pin disposed intermediate said shaft and said sear such that rotation of said shaft causes said hammer drop cam to engage said pin and translate said pin such that said pin abuts said sear and causes said sear to disengage said hammer such that said hammer falls to the decocked position; and

(j) wherein said first firing pin cam and said hammer drop cam are configured such that said firing pin is repositioned prior to said hammer falling to the decocked position.

4. The hammer drop mechanism of claim 3 further comprising:

(a) a second firing pin cam formed upon said shaft;

(b) a second camming surface formed upon said firing pin such that rotation of said shaft causes said second firing pin cam to engage said second camming surface; and

(c) wherein said first firing pin cam and said first camming surface operate in redundant fashion with said second firing pin cam and said second camming surface to reposition said firing pin such that said hammer is prevented from striking said firing pin.

5. The hammer drop mechanism of claim 4 wherein said shaft further comprises:

(a) a first shaft section upon which said lever and said second firing pin cam are formed;

(b) a second shaft section attachable to said first shaft section, upon which said first firing pin cam and said hammer drop cam are formed; and

(c) wherein rotation of the first shaft section causes a like rotation of the second shaft section.

6. The hammer drop mechanism of claim 5 further comprising:

(a) a slot formed upon said first shaft section; and

(b) a substantially flat portion formed upon said second shaft section such that said flat portion may be received by said slot to attach said first and second shaft sections together.

Description

FIELD OF THE INVENTION

The present invention relates generally to firearms and more particularly to an improved firearm having a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays.

BACKGROUND OF THE INVENTION

Firearms having inertial firing pins which, when struck by the hammer of the firearm, are driven forward to strike and discharge a cartridge are well known. Several devices have been proposed to selectively look the firing pin in order to prevent the firearm from being accidentally discharged. Such accidental discharge may occur in the event that the firearm is dropped from a distance of several feet and subsequently lands in such a manner that inertia carries the firing pin forward, thus causing it to strike the cartridge.

Manual firing pin locks are well known. They are typically located within the slide of an automatic or semiautomatic pistol and function to prevent the firing pin from contacting a chambered cartridge when activated. There is a tendency not to activate such manually operated firing pin lock mechanisms when it is anticipated that rapid and unexpected use of the gun may be required, e.g. during law enforcement or combat use. In such situations, the user does not want to be forced to remember to disengage the firing Pin lock under stressful conditions, nor does he want to take the time to do so.

Passive firing pin locks such as that described in U.S. Pat. No. 4,555,861 issued to Khoury are known. Such devices have the advantage of not requiring the user to manually engage and disengage the lock. Rather, the lock is automatically engaged when the trigger is in the nondepressed or unactuated position and is automatically disengaged when the trigger is in the depressed or actuated position.

Prior art passive firing pin locks such as the Khoury device suffer, however, from the inherent deficiency that the firing pin is necessarily free to travel forward any time the trigger is depressed, including during the chambering of a cartridge. In such firearms, a malfunction of the disconnector or sear can cause a normally semiautomatic gun to function in a fully automatic mode. A semiautomatic firearm discharges one cartridge each time the trigger is pulled. A fully automatic firearm continues to fire as long as the trigger is depressed and cartridges remain to be fired. Unexpected fully automatic operation could result in the firearm being discharged in an inappropriate direction, possibly resulting in injury or death. Since fully automatic operation requires a stronger grip on the firearm and a firm stance to maintain control of the firearm.

Additionally, since in the Khoury device the firing pin lock does not re-engage the firing pin until the trigger is released, it is possible that an accidental discharge could occur prior to releasing the trigger. For example, in a combat environment the firearm could be struck by a bullet or shrapnel immediately after the firearm has been fired but prior to releasing the trigger. During this time the passive firing pin lock of the Khoury device would be inactive and therefore would not function to prevent the firing pin from being driven forward and discharging the weapon. Therefore, it is possible that an accidental discharge could occur. Also, it is conceivable that the user could fall and permit the firearm to strike a hard surface prior to releasing the trigger, thus driving the firing pin forward and accidentally discharging the firearm.

It would therefore be desireable to lock the firing pin in a retracted position at all times except when it is explicitly desired that the firearm be discharged. This would prevent both unexpected fully automatic operation and accidental discharge.

Also, such contemporary passive firing pin locks are comparatively complex in their structure. The Khoury device is typical in this regard and includes a double lever and pin arrangement which is comparatively prone to malfunction due to excessive wear, contamination, or breakage. It would therefore be desirable to provide a mechanically simpler mechanism for preventing undesired forward motion of the firing pin.

Double action semi-automatic pistols are also well known in the art. Pulling the trigger of a double action pistol both cocks the hammer and causes it to fall upon the firing pin. This eliminates the need to separately cock the hammer prior to pulling the trigger. Thus, double action pistols are more effective when quick and unexpected use may be required.

Since the hammer of a double action semi-automatic pistol does not have to be separately cocked and the pistol is therefore capable of being fired by merely pulling the trigger, it is often desireable to keep a cartridge in the chamber. This permits rapid use of the pistol by merely aiming and pulling the trigger. To chamber a cartridge, the slide is pulled back and released, thereby stripping the top cartridge from the magazine and loading it into the chamber. This action also cocks the hammer of the pistol and leaves the hammer in a cocked position.

After chambering a cartridge, the hammer remains in a cocked position such that pulling the trigger will discharge the weapon. Various safety mechanisms are known for preventing inadvertent discharge of the firearm when the trigger is pulled while the hammer is in a cocked position. Such safety mechanisms generally either prevent the sear from releasing the hammer, lock the hammer in the cocked position, or prevent the trigger from being pulled. However, as with the manual firing pin look, the use of such a safety mechanism is often undesirable when rapid and expected use is likely.

Thus, it is often desireable to have a cartridge chambered, but due to the double action operation of the pistol, it is not necessary to maintain the hammer in a cocked position. Indeed, it is frequently more desireable to maintain the hammer in a decocked position. This is because it takes a substantially greater amount of force to depress the trigger and discharge the firearm when the hammer is in the decocked position. As such, additional force must be provided by the user to cock the hammer, instead of merely releasing it to fall upon the firing pin (i.e. it requires a much more deliberate action to depress the trigger of a decocked double action firearm than to depress the trigger of a cocked double action firearm). This additional force is necessary to overcome the hammer spring tension as the hammer is raised to the cocked position. Such additional force makes an accidental discharge less likely. For example, if a foreign object inadvertently engages the trigger, it is much less likely that an accidental discharge will occur if the hammer is decocked.

Therefore, a common problem associated with double action semi-automatic pistols is the safe lowering of the hammer after manually chambering a cartridge. It may be desired to lower the hammer, thus decocking the firearm, when the gun is to be carried in a holster, stored for an extended period of time, or when it is otherwise desireable not to have the hammer in a cocked position. Many police departments require that their officers carry their firearm with a cartridge in the chamber and the hammer in a decocked position.

A common method for decocking a firearm is to grasp the hammer with the fingers of one hand while holding the firearm in the other hand and pulling the trigger. Grasping the hammer prevents it from falling forcefully upon the firing pin and thus discharging the gun. However, occurrences of inadvertent discharges while attempting this procedure are not uncommon. Since such inadvertent discharges can cause injury and death, it is very desireable to provide a means for lowering the hammer of such a firearm in a safe and convenient manner.

Various decocking or hammer drop mechanisms are known. One such mechanism slowly lowers the hammer to its decocked position such that the hammer does not strike the firing pin with enough force to drive the firing pin into the chambered cartridge. Another mechanism rotates a portion of the firing pin out of the path of the falling hammer such that the hammer cannot strike the end of the firing pin. In this instance the trigger may be pulled to cause the hammer to drop, since it is prevented from striking the displaced firing pin. Alternatively, the mechanism which displaces the portion of the firing pin may also cause the hammer to drop.

A means for lowering the hammer in a single action semi-automatic pistol would likewise be desireable since it is often desired to maintain a single action semi-automatic pistol with a chambered cartridge. This is true even though the hammer of a single action pistol must be separately cocked prior to firing the first cartridge.

Additionally, in the prior art, much weight has been given to the ability of the barrel bushing to firmly secure the front end of the barrel in position. The accuracy of the firearm depends upon the repeatability with which the barrel can be repositioned relative to the sights.

Various bushings for repositioning the forward end of the barrel after each shot are well known. The simplest of such bushings merely receive the front end of the barrel, holding it in place until the firearm is discharged. During discharge, the bushing travels rearward along the barrel. When the barrel unlocks from the slide, the bushing permits slight rotation of the barrel relative to the slide. Such rotation is necessary to accommodate the unlocking/locking motion of the barrel. Such simple bushings must therefore incorporate a slightly oval, elongated, or oversized central aperture.

Through the use of close tolerances, an attempt is made to securely restrain the forward end of the barrel within the bushing prior to discharging the firearm. The requirement for such close tolerances causes the firearm's accuracy to degrade as the bushing wears and the tolerances are lost. Also, close tolerances require the mechanism be maintained comparatively free from contamination. Dirt, sand, lint, and other contaminants can cause the bushing to bind upon the barrel and jam the firearm. The use of close tolerances increases the rate at which the barrel bushing wears due to friction. Fabrication of barrel bushings having close tolerances is comparatively difficult and expensive.

Thus, the prior art has concentrated efforts for achieving superior accuracy upon the ability of the barrel bushing to firmly secure the forward end of the barrel in position. Other mechanisms, such as Colt's collet type barrel bushing disclosed in U.S. Pat. No. 3,564,967 issued to La Violette have been used to achieve this result. All such methods of firmly securing the forward end of the barrel in position are characterized by the requirement for closely held tolerances which tend to degrade over time and thus cause the firearm's accuracy to deteriorate.

Another common problem with prior art bushings is cracking due to the repeated application of stress when the gun is fired. This is particularly true of the Colt collet type bushing wherein comparatively delicate fingers secure the barrel in place. Such fingers are subject to the development of stress cracks. Consequently, they occasionally break off whereupon they may cause the gun to jam.

It would be desirable to repeatably position the barrel without requiring that the forward end of the barrel be firmly secured in place. It would also be desireable to eliminate the need for close tolerance in the fabrication of barrel bushings. Additionally, it would be desireable to provide a barrel bushing which is not susceptible to malfunction due to stress.

In addition, colored inlays formed upon the front and rear sights of firearms for aiding the user in the aiming process are well known. Typically a single round or rectangular inlay is provided upon the firearms front sight and two round inlays are provided on either side of the central groove of the rear site. Such inlays are typically colored either white or red to provide a stark contrast to the deep blue or black color of the gun sights. The use of colored inlays provides highly visible reference points by which the user can quickly align the sights upon a target.

Such inlays are used by aligning the inlay formed upon the front sight between the two inlays formed upon the rear sights. This process is hastened by the ease with which the colored inlays are perceived by the user. The red or white inlays can be quickly spotted and rapidly brought into rough alignment.

However, precise alignment of the prior art inlays is relatively difficult. The curved peripheries of the round inlays used upon the rear and/or front sights do not provide an easy means for judging alignment. In the prior art, the user must either align round rear inlays to a round front inlay or round rear inlays to a rectangular front inlay.

As will be recognized, it is difficult to align curved lines to each other or to a straight line. The curved lines do not provide a single reference for alignment, but rather present the user with the task of defining a reference. The user must align the round inlay by concentrating upon some portion thereof. For example, the user may attempt to visually determine the center point of the round inlay on the front sight and align it to similarly determined center points on round inlays of the rear sights.

Thus, although prior art firearms have proven generally suitable for their intended purposes, they possess inherent deficiencies which detract from their safe use and reduce accuracy below that theoretically obtainable. This detracts from their overall effectiveness in the marketplace.

In view of the shortcomings of the prior art, it is desirable to provide an improved firearm having a trigger actuated passive firing pin lock, a convenient and safe means for lowering the hammer of a firearm having a chambered cartridge, a barrel bushing which accurately repositions the forward end of the barrel relative to the sights, and sight inlays which allow the user to quickly and precisely aim the firearm.

SUMMARY OF THE INVENTION

The present invention specifically addresses and alleviates the above mentioned deficiencies associated in the prior art. More particularly, the present invention comprises an improved firearm having one or more safety and performance features such as a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays.

The passive firing pin lock of the present invention prevents an accidental discharge when the gun is dropped. The passive firing pin look is comprised of a lever which engages the firing pin and locks the firing pin in position such that the firing pin cannot travel forward and discharge a chambered cartridge. The lever pivots about a pin between an engaged or safe position and a disengaged or fire position. The lever is biased in the safe position by a spring.

Pulling the trigger rotates the sear to disengage a catch formed upon the sear from a notch formed upon the hammer and thus permits the hammer to fall. Prior to rotating sufficiently to cause the hammer to fall, a pawl formed upon the sear engages a tab formed upon the passive firing pin lock lever, thus causing the lever to disengage the firing pin. This places the lever in the fire position wherein further rotation of the sear will cause the hammer to drop upon the firing pin and drive the firing pin forward, thus discharging the firearm.

Upon ignition of the propellant contained within the cartridge, the firing pin is immediately urged rearward by both the firing pin spring and a dynamic impulse imparted as gas pressure tends to re-flatten the primer. Upon retraction to its original position, the firing pin is immediately looked into place by the passive firing pin lock lever. This occurs prior to the user releasing the trigger. Thus, the firing pin is immediately locked into a safe position and the gun is thereby protected from accidental discharge.

By immediately locking the firing pin in a safe position, prior even to releasing the trigger, the probability of an accidental discharge is substantially reduced. For instance, if the gun should be forcibly struck, i.e. by a bullet or shrapnel, immediately after a shot has been fired, but prior to releasing the trigger, the firing pin will have been locked in a safe position and the gun will be prevented from discharging. Also, in the event that the user falls after firing a shot but prior to releasing the trigger, and the gun strikes a hard surface with sufficient force to drive the firing pin forward, the gun is again prevented from discharging.

The manufacture of a pistol having the passive firing pin lock of the present invention essentially involves the fabrication of a lever and a modification of the sear. By contrast, manufacture of the Khoury device involves the fabrication of two separate lever mechanisms and a pin lock. Thus, manufacture of the firing pin lock of the present invention involves fewer materials, less machining, and simplified assembly. This provides a substantial savings in manufacturing costs.

Additionally, locking of the firing pin in the safe position without the necessity of the trigger being released precludes the possibility that the pistol could operate in the fully automatic mode in the event of a sear or disconnector malfunction. Operation of the firearm in the fully automatic mode is extremely dangerous since it typically occurs unexpectedly and results in the rapid discharge of several cartridges. In the event of such an occurrence the user often does not maintain full control of the firearm since the discharge of more than one cartridge is not expected. Therefore, several shots could be fired in an unsafe direction, resulting in death or injury. The ability to lock the firing pin in place immediately without the necessity of releasing the trigger therefore reduces the likelihood of such an occurrence.

The passive firing pin lock of the present invention is also particularly well suited for use in a double action only firearm While most double action firearms can be operated in either a double action or single action mode, double action only firearms can only be fired in a double action mode. Double action only firearms do not have a hammer notch and sear catch for holding the hammer in a cocked position and must therefore be fired from the decocked position, i.e. in a double action mode.

In a double action only firearm it is often desired that the weapon be as simple to operate as possible. Thus, external manually operated safeties are not desirable. It is usually intended that such firearms be capable of being used by merely aiming and pulling the trigger.

Since the hammer of a double action only firearm does not remain in a cooked position after firing, it follows the slide forward as the next round is chambered. The hammer thus pushes the firing pin slightly forward as the slide moves into battery. Therefore, the firing pin may actually contact the primer of a chambered cartridge as the slide is brought into battery. While the firing pin does not strike the primer with sufficient force to cause the firearm to discharge, it is nevertheless undesirable to permit the firing pin to contact the primer except when a discharge is intended.

The passive firing pin lock of the present inventory prevents the firing pin from contacting the primer of a chambered round as the slide is brought into battery. This adds an extra margin of safety to the firearm. The firing pin cannot contact the primer since the firing pin is locked into a retracted position as the slide travels rearward and remains locked as the slide moves forward into battery.

The passive firing pin lock of the present invention thus provides a means whereby a double action only firearm may be constructed without the need for an externally operated manual safety and without permitting the firing pin to contact the primer of a chambered round as the slide moves into battery after the round is chambered.

In addition, the present invention incorporates a novel hammer drop mechanism which permits the hammer to be safely lowered when a cartridge is present in the chamber. This is accomplished without touching the trigger of the firearm. The hammer drop mechanism is comprised of first and second hammer drop shafts which are inserted into the slide at diametrically opposed positions and connect to form a single shaft having three cam surfaces formed thereupon. An external thumb lever formed upon one of the shafts permits the shaft to be manually rotated by the user. Rotation of the shaft engages two of the cams against the firing pin, thus withdrawing the firing pin beyond the firing pin retainer and into the slide such that the hammer can no longer strike the firing pin. Further rotation of the shafts cams a hammer drop push rod downward against the sear, thus causing the sear to rotate and release the hammer.

The use of two cams to withdraw the firing pin provides redundancy such that the firing pin will be safely retracted in the event of excessive wear or malfunction of one of the cams. Thus, even if one cam fails, the firing pin will still be retracted within the slide prior to the hammer falling.

Therefore, in operation the hammer drop mechanism of the present invention first repositions the firing pin within the slide to prevent contact with the hammer and then actuates the hammer causing it to fall to a decocked position. The hammer drop mechanism of the present invention thereby provides a safe and convenient means for a user to lower a semi-automatic pistol's hammer when a cartridge is chambered.

A V-block type barrel bushing of the present invention accurately repositions the forward end of the barrel relative to the sights to provide maximum accuracy. The V-block type barrel bushing of the present invention is comprised of two flat contact surfaces formed as an integral part of the slide and configured to contact the front end of the barrel tangentially at two locations. The use of such a V-block provides an extremely accurate means for repeatably positioning a cylindrical object. Thus, in the same manner that a machinist might axially position a section of bar stock prior to drilling, the forward portion of the barrel is precisely positioned prior to discharging the pistol.

Since the V-block bushing of the present invention does not attempt to firmly secure the front end of the barrel in place but rather repeatedly locates the front end of the barrel in a consistent position relative the slide, friction is minimized and bushing failure is eliminated. Also, the requirement for close tolerance machining is eliminated since the exact positioning and dimensions of the V-block are unimportant. It is merely necessary that the two contact surfaces be formed at approximately the five and eight o'clock positions and be tangential to the barrel. Use of the V-block barrel bushing of the present invention therefore provides the best accuracy theoretically possible while eliminating the prior art problems of wear and malfunction.

Further, the present invention discloses the use of square sight inlays or indicia. The square sight markings of the present invention are preferably comprised of a single square inlay formed upon the front sight and one square inlay formed upon either side of the groove in the rear sight. The square inlays are positioned such that when all three of their upper and lower edges are aligned and the square inlay formed upon the front sight is centered between the square inlays formed upon the rear sights, then the gun is on target. The advantages of such square inlays lie in the ability to rapidly align their upper and lower edges and the ability to perceive very small discrepancies in alignment.

It is a simple matter for the user to vary the elevation of the gun to achieve alignment of the upper and lower edges of the square inlays. The user simply concentrates upon either the upper or lower edges of the square inlays and tilts the gun to bring them into alignment. When aligned, both the upper and lower edges of the square inlays form a pair of single lines such that any deviations in the alignment of the inlays is immediately apparent and can be corrected.

Alignment of sights having round inlays is far more difficult by comparison. There are no straight lines for the user to bring into alignment. Therefore the user must rely upon his ability to perceive corresponding points within each round inlay and attempt to align these imagined corresponding points. For example, the user may concentrate upon aligning the centers of the round inlays. This is extremely difficult since the centers are only defined within the user's mind and are therefore extremely difficult to align with any precision. The user may also attempt to align the sights by concentrating upon the uppermost portion of the outer perimeter of each round inlay. This is likewise extremely difficult since the precise location of the uppermost point of the perimeter of each round inlay again exists only within the user's mind. The user must therefore attempt to determine the precise location of either the center, uppermost portion of the perimeter, or some other distinctive portion of each round inlay and do this subconsciously while also aligning the sights upon the target.

Aligning the square inlay sights of the present invention in azimuth is also greatly simplified over contemporary round inlays. In the present invention it is simply necessary to insure that the front sight square inlay is centered between the two rear sight square inlays by rapidly providing an equal distance between each of the two rear sight square inlays and the front square inlay. This is a simple matter since the user is aligning straight vertical lines. That is, it is a simple matter to visually determine the distance between vertical straight lines. By contrast, it is far more difficult to determine the distance between adjacent circular edges. In order to determine the distance between adjacent circular edges, it is first necessary to imagine points upon each of the circular edges from which the determination is to be made. Thus, the user must again use judgement to form an imaginary point upon the circumference of each of the round inlays and to form a mental measurement therebetween.

As such, the square sight inlays of the present invention provide a means of rapidly and accurately aligning the sights upon a target without having to rely upon the user's ability to mentally measure distances between curved objects. The square sight inlays thus allow the user to quickly and precisely aim the firearm.

These, as well as other advantages of the present invention will be more apparent from the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the right side of a semi-automatic pistol in accordance with the preferred embodiment of the present invention;

FIG. 2 is a perspective view of the left side of the semi-automatic pistol of FIG. 1;

FIG. 3 is a perspective view of the passive firing pin lock of the present invention showing the sear, sear housing, passive firing pin lock lever, and the firing pin, the firing pin being shown in the phantom, and the passive firing pin lock lever being shown partially in phantom;

FIG. 4 is an exploded view of the sear housing, sear, passive firing pin lock lever, and firing pin of FIG. 3;

FIG. 5 is a perspective view of the sear, passive firing pin look lever and a portion of the firing pin of FIG. 4;

FIG. 6 is a sectional view of the sear and a portion of the passive firing pin lock lever taken along line 6--6 of FIG. 5;

FIG. 7 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1;

FIG. 7A is an enlarged cross-sectional side view of the rear portion of the slide and receiver shown in FIG. 7 depicting the hammer in its cocked position, the sear engaging the hammer and the passive firing pin lock lever positioned to block the forward motion of the firing pin;

FIG. 8 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the hammer in the cocked position, the sear disengaged from the hammer, and the passive firing pin lock lever disengaged from the firing pin;

FIG. 9 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the hammer in the decocked position, the sear disengaged from the hammer, the passive firing pin lock lever disengaged from the firing pin, and the firing pin in its forward most position;

FIG. 10 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the slide in its rear most position, the hammer in its cocked position, the passive firing pin lock lever engaging the firing pin, and the sear engaging the hammer;

FIG. 11 is an exploded perspective view of the hammer drop mechanism of the present invention showing the first and second hammer drop shafts, the rear most portion of the firing pin the hammer drop push rod, and a portion of the sear;

FIG. 11A is a cross-sectional view of the first and second hammer drop shafts taken along line 11A of FIG. 11 and a roll pin used to attach them together;

FIG. 12 is a perspective view of the second hammer drop shaft, the hammer drop push rod, and a portion of the sear of FIG. 11 showing the cam formed upon the second hammer drop shaft for camming the hammer drop push rod against the sear;

FIG. 13 is a sectional perspective view of a portion of the firing pin of FIG. 11 showing the two camming surfaces upon which the two cams formed upon the first and second hammer drop shafts act;

FIG. 14 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever in the horizontal or unactuated position;

FIG. 14A is an enlarged cross-sectional view of the hammer drop push rod cam engaging the hammer drop push rod as shown in FIG. 14;

FIG. 14B is an enlarged cross-sectional view of the first firing pin cam about to engage the first firing pin camming surface of the firing pin as shown in FIG. 14;

FIG. 14C is an enlarged side view of the second firing pin cam about to engage the second firing pin camming surface as shown in FIG. 14, the second firing pin camming surface being shown in dashed lines;

FIG. 15 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever depressed to a position approximately midway in its travel;

FIG. 15A is an enlarged cross-sectional side view of the hammer drop push rod cam engaging the hammer drop push rod as shown in FIG. 15;

FIG. 15B is an enlarged cross-sectional side view of the first firing pin cam engaging the first firing pin camming surface of the firing pin as shown in FIG. 15;

FIG. 15C is an enlarged side view of the second firing pin cam engaging the second firing pin camming surface of the firing pin as shown in FIG. 15;

FIG. 16 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever in its fully depressed position;

FIG. 16A is an enlarged cross-sectional side view of the hammer drop push rod cam depressing the hammer drop push rod as shown in FIG. 16;

FIG. 16B is an enlarged cross-sectional side view of the first firing pin cam engaging the first firing pin camming surface of the firing pin as shown in FIG. 16;

FIG. 16C is an enlarged cross-sectional side view of the second firing pin cam engaging the second firing pin camming surface of FIG. 16;

FIG. 17 is a front view of the V-block bushing of the present invention formed within the slide of the pistol of FIG. 1;

FIG. 18 is a cross-sectional side view of the V-block bushing of FIG. 17;

FIG. 19 is a cross-sectional side view of the rear sight of the pistol of FIG. 1;

FIG. 20 is a cross-sectional view taken about lines 20--20 of the rear sight of FIG. 19 showing the two square inlays of the present invention;

FIG. 21 is a perspective view of the front and rear sights showing the square inlays;

FIG. 22 is a rear view of the front and rear sights of FIG. 21; and

FIG. 23 is a rear view of the slide of the pistol of FIG. 1 showing alignment of the square inlays of the front and rear sights with a bull's-eye.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

The firearm of the present invention is illustrated in FIGS. 1-23 which depict a presently preferred embodiment of the invention. Referring now to FIGS. 1 and 2, a pistol 10 in accordance with the present invention is comprised generally of a receiver 24 and a slide 22 disposed for reciprocal motion upon the receiver 24. A trigger 12 protrudes from the lower portion of receiver 24 to actuate, through conventional internal mechanisms, a hammer 14. A manually operated safety 25 prevents the trigger 12 from discharging the pistol 10 as in the prior art. As is well known, when trigger 12 is actuated, the hammer 14 strikes firing pin striking surface 54 and firing pin retainer 28. Rear 18 and front 20 sights provide for the alignment of barrel 30 with a target. In the preferred embodiment, the pistol 10 comprises a semi-automatic handgun, such as that depicted in U.S. Pat. No. 4,726,136 issued to Dornaus et al. the disclosure of which is expressly incorporated herein by reference. In this regard, the present invention comprises a specific improvement over the hand gun disclosed in U.S. Pat. No. 4,726,136 but is additionally applicable to other types of firearms.

Referring now to FIGS. 3 through 6, the passive firing pin look of the preferred embodiment of the present invention is depicted. A sear 32 is pivotally disposed within sear housing 36. Sear housing 36 is disposed within the receiver of FIGS. 1 and 2 proximate the hammer 14. The sear 32 pivots about sear pin 34. An arm 48 extends from the sear 32 and has a pawl 50 formed upon the distal end thereof.

Passive firing pin lock lever 38 is pivotally mounted within the slide 22 above the sear 32. Lever 38 pivots about lever pin 41 (shown in FIG. 7 and 7A) which extends through aperture 40 formed in lever 38. Lever 38 has a detent 42 formed upon one end thereof. A tab 46 extends perpendicularly from approximately the middle of the lever 38. A contact surface 52 is formed upon the upper surfaces of the tab 46.

An inertial firing pin 26 is disposed within the slide 22 immediately above the passive firing pin lock lever 38. The firing pin 26 has a recess 44 formed in the lower rear surface thereof and sized to receive the detent 42 formed upon the lever 38. Firing pin striking surface 54 of firing pin 26 extends through the firing pin retainer 28 as shown in FIG. 2.

In the present invention, as well as in the prior art, depression of the trigger 12 is mechanically communicated to the sear 32 via linkage (not shown), thus causing the sear to rotate to permit the hammer 14 to fall upon the firing pin retainer 28 and striking surface 54 of the firing pin 26. The firing pin 26 is thus driven forward toward the primer of a chambered cartridge, against the biasing force of a firing pin spring 62 (as shown in FIGS. 7-10). The inertia of the firing pin 26 causes it to strike the primer with sufficient force to detonate the primer, thus discharging the firearm.

Clockwise (as viewed in FIG. 3) rotation of the lever 38 engages a detent 42 within a recess 44 formed in the lower rear portion of the firing pin 26. Engagement of the detent 42 within the recess 44 of firing pin 26 thus prevents forward translation of the firing pin 26 within the slide 22. Clockwise rotation of the sear 32 causes the tab 46 formed upon lever 38 to be engaged by pawl 50 of sear 32.

As can be seen in the cross sectional view of FIG. 6, the pawl 50 formed upon the distal end of arm 48 engages contact surface 52 of tab 46 when pawl 50 moves downward in response to clockwise rotation of the sear 32. Thus, clockwise rotation of the sear 32 causes lever 38 to rotate counterclockwise, and to disengage detent 42 from recess 44 of firing pin 26. Detent 42 of the passive firing pin lock lever 38 engages the recess 44 formed within firing pin 26 at all times except when the trigger 12 is depressed to fire the pistol 10.

As in the prior art, clockwise rotation of the sear 32 disengages the hammer 14 from the sear 32 thus permitting the hammer 14 to fall and strike the firing pin 26. The firing pin 26 travels forward to discharge a chambered round in response to the striking surface 54 of the firing pin 26 being struck by the hammer 14. The detent 42 of the present invention is disengaged from the recess 44 of the firing pin 26 immediately prior to the disengagement of the hammer 14 from the sear 32.

The detent 42 is engaged within the recess 44 of the firing pin 26 at all times other than when the trigger 12 is depressed, thus effectively preventing accidental discharge of the pistol 10. Dropping of the pistol 10 with its barrel downward, such that an accidental discharge would be likely in a prior art pistol, thus does not cause the firing pin 26 to travel forward under the force of its own inertia when the firearm strikes the floor.

Operation of the passive firing pin lock of the present invention is presented in further detail with reference to FIGS. 7-10 wherein the lock is depicted in its various stages of operation as the trigger 12 is pulled and the pistol 10 is discharged.

With particular reference to FIGS. 7 and 7A, the pistol 10 is depicted with the hammer 14 in a cocked position and a cartridge 66 loaded in the chamber 30. The striking surface 54 of the firing pin 26 extends beyond the firing pin retainer 28 such that the hammer 14 will contact the striking surface 54 of the firing pin 26 and drive the firing pin 26 forward toward the cartridge 66 when the hammer 14 is released. Since the trigger has not yet been depressed, detent 42 on lever 38 is received by recess 44 of firing pin 26. Thus, the firing pin 26 is looked in a safe position and thereby prevented from translating forward and striking the cartridge 66. Spring 68 disposed against surface 70 of lever 38 biases lever 38 into this safe position.

If the pistol were to be dropped while in this safe configuration, the firing pin 26 would be prevented from moving forward under its own inertia and striking cartridge 66 with the tip 64 thereof. Thus, the probability of death or injury due to accidental discharge is reduced.

The sear catch 74 of sear 32 engages the hammer notch 72 of the hammer 14, thus maintaining the hammer 14 in its cocked position until the trigger 12 is pulled. Pulling the trigger 12 at this point will rotate (through a conventional mechanical linkage which is not shown) the sear 32 clockwise, thus disengaging sear catch 74 from hammer notch 72 and permitting the hammer to rotate clockwise under the biasing of the hammer spring (not shown), whereupon the hammer 14 will strike the striking surface 54 of the firing pin 26 and the firing pin retainer 28. Pawl 50 formed upon the end of arm 48 of the sear 32 does not contact tab 46 of lever 38 when the trigger 12 is not depressed.

With particular reference to FIG. 8, the passive firing pin lock is depicted after the trigger 12 has been depressed. Depressing the trigger 12 has caused the sear 32 to rotate clockwise sufficiently to permit sear catch 74 to disengage from hammer notch 72 such that hammer 14 will begin to rotate clockwise under the urging of the hammer spring (not shown), whereupon the hammer 14 will strike striking surface 54 and firing pin retainer 28. Immediately prior to sear catch 74 disengaging hammer notch 72, pawl 50 contacts tab 46 of the lever 38 and urges tab 46 downwardly. This causes detent 42 to disengage from recess 44. Thus, as hammer 14 rotates clockwise to strike the striking surface 54 of firing pin 26, firing pin 26 is unlocked from its safe configuration and placed in a fire configuration wherein firing pin 26 is free to travel forward to cause the discharge of the pistol 10.

With particular reference to FIG. 9, hammer 14 has struck the striking surface 54 of the firing pin 26, thus driving the firing pin 26 forward against the urging of spring 62. The tip 64 of firing pin 26 thus strikes cartridge 66 to discharge the pistol 10. The pawl 50 of the sear 32 holds the lever 38 in the fire configuration as the firing pin 26 rebounds rearward under the urging of spring 62.

With particular reference to FIG. 10, the reaction to the lead bullet moving forward causes the slide 22 to rapidly recoil longitudinally rearward, thus cocking the hammer 14, extracting the expended cartridge, and permitting another cartridge to be chambered. As the slide 22 travels rearward, tab 46 of lever 38 disengages sear pawl 50, thus permitting detent 42 to be again received by recess 44 of the firing pin 26.

Therefore, firing pin 26 is once again locked into the safe configuration before slide 22 returns to its rest position. As in the prior art, sear 32 rotates counterclockwise such that sear catch 74 engages hammer notch 72 thus preventing the hammer 14 from rotating clockwise and again striking the striking surface 54 of the firing pin 26. Thus, as the slide returns to its forward most position, the safe configuration of the firing pin 26 is once again attained.

Referring now to FIGS. 11 through 13, the hammer drop mechanism of the present invention is depicted. The hammer drop mechanism is generally comprised of first 100 and second 102 shafts, the firing pin 26, hammer drop push rod 104, and sear 32. The first shaft 100 has a thumb actuation lever 106 formed upon one end thereof and a shaft recess 110 and second firing pin cam 108 formed upon the opposite end thereof. The second shaft 102 has a flat shaft portion 112, a first firing pin cam 114 and a hammer drop cam 116 formed thereupon.

First 100 and second 102 shafts are inserted into the slide 22 such that they may be attached together with pin 101 to form a single shaft which passes transversely through the slide 22 Pin 101 extends through aperture 119 in second shaft 102 and through aperture 121 in first shaft 100. Therefore, rotation of the first shaft 100 by depressing thumb lever 106 causes a like rotation of second shaft 102.

With particular reference to FIG. 12, the upper end 118 of hammer drop push rod 104 contacts the hammer drop cam 116 of second shaft 102 and the lower end 120 contacts the arm 48 of the sear 32. The flat shaft portion 112 is formed to be received by the shaft recess 110 of the first shaft 100. Thus, first shaft 100 and second shaft 102 attach together to form a single rotatable member.

With particular reference to FIG. 13, the firing pin 26 includes a first camming surface 124 and a second camming surface 122 formed thereon. The first camming surface 124 is adapted to engage the first firing pin cam 114 and the second surface 122 is adapted to engage the second firing pin cam 108.

The firing pin 26 is prevented from rotating about its longitudinal axis by the abutment of the lower surface 115 of the second shaft 102 against the upper flat surface 127 of recess 126 formed in the firing pin 26 and by the abutment of the edge 117 of the first shaft 100 against the flat side 125 of the firing pin 26.

Operation of the hammer drop mechanism of the present invention is presented in detail with reference to FIGS. 14 16C wherein the mechanism is depicted in various stages of operation as the thumb lever is depressed. Thumb lever 106 is biased in the up or unactuated position by the firing pin spring 62 acting through the firing pin 26 and by the hammer drop pin spring 105 acting through the hammer drop pin 104. Actuation of the thumb lever 106 cams the firing pin 26 into the slide 22 such that the striking surface 54 of the firing pin 26 is disposed beneath the hammer striking or outer surface 29 of the firing pin retainer 28 and consequently cannot be struck by the hammer 14. Further rotation of the thumb lever 106 actuates the sear 32, thus releasing the hammer 14 and permitting it to fall to a decocked position.

With particular reference to FIG. 14, the firing pin 26 is depicted in its rest position. The striking surface 54 of the firing pin 26 extends beyond the hammer striking or outer surface 29 of the firing pin retainer 28. The hammer drop cam 116 lightly contacts the upper end 118 of the hammer drop push rod 104. The first firing pin cam 114 is positioned almost in contact with the first camming surface 124 of the firing pin 26. The second firing pin cam 108 is positioned slightly above the second camming surface 122 of the firing pin 26. The hammer 14 is shown in the cocked position and maintained therein by the sear 32.

The hammer drop push rod 104 is disposed intermediate the second shaft 102 and the sear 32 such that rotation of the second shaft 102 in a clockwise direction by manipulation of the lever 106 will cause the hammer drop cam 116 to abut the uppermost end 118 of the hammer drop push rod 104 and translate the lower end 120 of the hammer drop push rod 104 downwardly against the bias of hammer drop push rod spring 105 into contact with the arm 48 of the sear 32. Continued rotation of the second shaft 102 in the clockwise direction rotates the arm 48 of the sear 32 downward, thus causing the sear catch 74 of the sear 32 to disengage the hammer notch 72 of the hammer 14. This permits the hammer 14 to rotate clockwise under the urging of the hammer spring (not shown). The three camming actions are discussed and illustrated in greater detail with respect to FIGS. 14A-14C.

With particular reference to FIG. 14A, when the thumb lever 106 is in the horizontal or rest position as in FIG. 14, the hammer drop cam 116 abuts the upper end 118 of the hammer drop push rod 104 without urging the hammer drop push rod 104 downward. That is, the upper end 118 of the hammer drop push rod 104 contacts the hammer drop cam 116 of the second hammer drop shaft 102 under the urging of hammer drop push rod spring 105 and there is no downward force upon the hammer drop push rod 104.

With particular reference to FIG. 14B, with the thumb lever 106 in the horizontal or rest position as in FIG. 14, the first firing pin cam 114 is positioned almost in contact with the first camming surface 124 of the firing pin 26 without urging the firing pin 26 forward.

With particular reference to FIG. 14C, with the thumb lever 106 in the horizontal or rest position as in FIG. 14, the second firing pin cam 108 does not contact the second camming surface 122 of the firing pin 26.

Referring now to FIGS. 15-15C, the positions and interactions of the various components of the hammer drop mechanism of the present invention are shown when the thumb lever 106 has been rotated clockwise through approximately one half of its travel i.e. approximately 30 degrees from its initial at rest position of FIGS. 14A-14C. Rotating the thumb lever 106 to an intermediate position brings the hammer drop cam 116 firmly into contact with the upper end 118 of the hammer drop push rod 104. The hammer drop push rod 104 may translate downward slightly, but not sufficiently to cause rotation of the sear 32. Such rotation of the thumb lever 106 also causes first 114 and second 108 firing pin cams to begin camming the firing pin 26 forward such that the firing pin 26 is partially withdrawn into the slide 22.

In this position, the striking surface 54 of the firing pin 26 is approximately flush with the outer surface 29 of the firing pin retainer 28. Therefore, the firing pin 26 is withdrawn to a point where the dropping hammer 14 is incapable of driving the firing pin 26 forward to discharge the pistol 10. The firing pin 26 is withdrawn in this manner prior to initiating the process of disengaging the sear 32 from the hammer 14. That is, the hammer is prevented from falling upon the striker plate 28 until the firing pin 26 is well beneath the outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 15A, with the thumb lever 106 in an intermediate position as in FIG. 15, the hammer drop cam 116 is brought into firm contact with the upper end 118 of the hammer drop push rod 104 such that slight pressure begins to be applied to the arm 48 of the sear 32. The hammer drop cam 116 has not yet begun to urge hammer drop push rod 104 appreciably downward. Thus, the sear 32 does not yet begin to rotate clockwise and the sear catch 74 consequently firmly engages hammer notch 72 of the hammer 14.

With particular reference to FIG. 15B, with the thumb lever 106 in an intermediate position as in FIG. 15, first firing pin cam 114 has urged firing pin 26 forward sufficiently to bring the striking surface 54 of the firing pin 26 approximately flush with the outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 15C, with the thumb lever 106 in an intermediate position as in FIG. 15, second firing pin cam 108 provides a redundant means for urging firing pin 26 forward as thumb lever 106 is depressed. Second firing pin cam 108 abuts camming surface 122 formed upon firing pin 26 to simultaneously urge firing pin 26 forward in concert with cam 114 and camming surface 124. The redundant camming action assures that the striking surface 54 of the firing pin 26 is safely withdrawn into the slide 22 prior to dropping of the hammer 14. Thus, even in the event of wear or malfunction of one of the first 114 and second 108 firing pin cams and/or their corresponding camming surfaces 124 and 122, a safe means for lowering the hammer is maintained.

Referring now to FIGS. 16-16C, the position of the hammer drop mechanism as the thumb lever 106 is rotated through its full travel i.e. approximately 60 degrees from its initial at rest position of FIGS. 14A-14C is depicted. As the thumb lever 106 nears the completion of its travel to the fully clockwise rotational position, the striking surface 54 of the firing pin 26 is withdrawn well below the outer surface 29 of the firing pin retainer 28 and the sear catch 74 disengages the hammer notch 72, thus allowing the hammer 14 to fall to a decocked position.

With particular reference to FIG. 16, the hammer has dropped from its cocked position and rests upon the firing pin retainer 28. With the thumb lever 106 in its fully rotated position the firing pin 26 is cammed forward such that the striking surface 54 thereof is disposed within the firing pin retainer 28 and cannot be contacted by the hammer 14 as the hammer 14 falls. The hammer 14 is prevented from striking the firing pin 26 and thereby discharging the pistol.

Thumb lever 106 and the rotatable member comprised of first 100 and second 102 shafts thus provide a single or common means for withdrawing the firing pin 26 and lowering the hammer 14. The three camming actions are discussed and illustrated in greater detail with respect to FIGS. 16A-16C.

With particular reference to FIG. 16A, it can be seen that the hammer drop cam 116 has urged the hammer drop push rod 104 against the urging of hammer drop push rod spring 105 fully to its lowermost position wherein the hammer drop push rod 104 has urged the sear 32 to rotate in a clockwise direction, thereby disengaging the sear catch 74 from the hammer notch 72.

With particular reference to FIG. 16B, with the lever 106 fully depressed as in FIG. 16 the first firing pin cam 114 has urged the firing pin 26 forward sufficiently to withdraw the striking surface 54 of the firing pin 26 beyond the hammer striking or outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 16C, with the thumb lever 106 fully depressed as in FIG. 16, in redundant fashion the second firing pin cam 108 has urged the firing pin 26 forward. The redundant operation of the first 114 and second 108 firing pin cams insures that the firing pin 28 is safely withdrawn beyond the hammer striking or outer surface 29 of the firing pin retainer 28 before the hammer 14 is released by the sear 32 to strike the firing pin retainer 28. Thus, the hammer 14 is safely decocked without discharging the pistol 10.

In addition to the improved safety features obtained by the present invention's use of the passive firing pin lock mechanism and hammer drop mechanism, the present invention provides improved performance characteristics by of a V-block bushing and square front and rear sight system. Referring more particularly to FIGS. 17 and 18, the V-block bushing feature of the present invention is illustrated. As is conventional, the distal end of the slide 22 is provided with a bushing 55 which is threadingly inserted or press fit therewithin. The purpose of the bushing is to maintain the distal end of the barrel which is disposed within the interior of the slide 22 and position the distal end of the barrel at a repeatable location relative the slide 22 prior to discharge of pistol 10.

In contrast to prior art bushings, the bushing 55 of the present invention comprises a V-block bushing having a pair of tangential flats 56 formed adjacent its lower periphery adapted to tangentially contact the exterior diameter of the barrel 31. As best shown in FIG. 17, with the barrel 31 disposed in its fire position the exterior of the barrel 31 contacts the flats 56 formed on the V-block bushing 55 to axially center the barrel 31 relative the bushing 55 and thus the slide 22. Due to the barrel 31 being pivotally connected to the slide adjacent its opposite end and is thereby urged downwardly upon the flats 56 by lever action, the lower diameter of the barrel 31 contact the flats 56 at two tangential points, i.e. contact points 58 as indicated in FIG. 17.

As such, during movement of the slide 22 relative to the barrel 31, as during chambering of a cartridge within the barrel, upon the barrel 31 returning to its final position relative the slide 22, the barrel 31 is consistently and repeatably positioned at the same axial and vertical position relative the slide 22. Due to this repeatability, accuracy and discharge of the pistol 10 is effectuated merely by proper adjustment of the sight system of the pistol 10.

In FIGS. 19 through 23, the improved sight system of the present invention is depicted. As will be recognized, the sight system comprises a rear sight assembly 18 disposed within a recess 128 formed on the rear end of the slide 22 and a front sight 20 disposed on the opposite or front end of the slide 22 as best seen in FIGS. 1 and 2.

Referring now to FIGS. 19 through 21, the square inlay rear sight 18 of the present invention is depicted. One square inlay 76 is formed upon either side of the sight groove 78. The rear sight 18 is adjusted for elevation by turning elevation adjustment screw 80 to cause the rear sight 18 to pivot about windage adjustment screw 82 against the biasing of rear sight spring 84. Windage adjustment screw 82 secures rear sight 18 within recess 128 formed in slide 22.

Windage is adjusted by turning windage adjustment screw assembly 82 from the right side. Windage adjustment screw assembly 82 is comprised of screw 83 and slotted nut 85 such that a screwdriver can engage the windage adjustment screw assembly 82.

First ball detent 86 is urged outward by spring 87 to engage recesses 88 formed within the rear sight 18 and locks elevation screw 80 in position. A similar ball detent 90 is urged outward by spring 91 and is received by similar recesses 92 to lock windage screw 82 in position.

As shown in FIG. 21, the square inlay front sight 20 of the present invention has a single square inlay 84 formed upon its rear surface. The front sight 20 is secured to the slide 22 using two posts 86. The posts 86 are received within complimentary apertures formed within the slide 22 and the posts are peened to form flared ends 87 which secure the posts 86 therein as shown in FIG. 18.

Each square indicia inlay 76 or 84 is preferably formed by first forming a shallow square recess where the inlay is to be located. The recess is then filled with red or white epoxy, enamel, or other durable colored material. Those skilled in the art will recognize that other processes of forming the inlays are likewise suitable. Additionally, those skilled in the art will recognize that the square markings or indicia may simply be affixed upon the sights 18 and 20 as opposed to being inlayed or recessed therein.

Referring now to FIG. 22 and 23, operation of the rear 18 and front 20 sights is depicted. In use, the upper and lower straight edges of the square inlays 76 and 84 are aligned to lie within a pair of straight lines A and B, thus aligning the pistol 10 in elevation. The vertical lines of the square inlays 76 and 84 are aligned such that equal distances C and D are achieved between the front sight inlay 84 and the two rear sight inlays 76. Alignment of the rear 18 and front 20 sights with a bull's-eye 130 is shown in FIG. 23. Such alignment can be rapidly and accurately obtained due to the ease with which straight lines can be visually aligned. It is a relatively simple matter to judge when the upper surfaces, for instance, of each square inlay 76 and 84 form a single straight line A. It is also relatively simple to judge the distances between adjacent inlays such that equal spacing of C and D is achieved.

Rear 76 and front 84 inlays are sized such that they appear approximately equal in linear dimensions to the user. That is, the front square inlay 84 is sized slightly larger than the two rear square inlays 76 so that when viewed in perspective by the user the more distant front square inlay 84 appears approximately equal in size to the closer rear inlays 76. This, of course, is most important when using the square inlays of the present invention upon a rifle wherein the distance between the front and rear sights is substantial.

While squares having four straight edges are depicted for each inlay 76 and 84, those skilled in the art will recognize that only the inboard vertical edges of rear sight inlays 76 and both vertical edges of front sight inlay 84 as well as either the top or bottom horizontal edges of all three inlays 76 and 84 need to be straight. This permits the definition of line A or B and distances C and D.

It is understood that the exemplary firearm described herein and shown in the drawings represents only a presently preferred embodiment of the invention. Indeed, various modifications and additions may be made to such embodiment without departing from the spirit and scope of the invention. For example, the lever of the passive firing pin lock could engage the firing pin in a variety of different ways. Also, various hammer drop mechanism configurations are possible for withdrawing the firing pin prior to actuating the sear and causing the hammer to fall. Additionally, the V-block barrel bushing may be formed as a separate removable element rather than as an integral portion of the slide as described. Additionally, the sight inlay of the present invention need not be square, but rather may use a variety of different shapes which provide straight horizontal and/or vertical surfaces which may be quickly and accurately aligned. Thus, these and other modifications and additions may be obvious to those skilled in the art and may be implemented to adapt the present invention for use in a variety of different applications.

* * * * *

[US Patent & Trademark Office, Patent Full Text and Image Database]

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United States Patent	5,426,882
Dornaus	June 27, 1995

Firearm having improved safety and accuracy features

Abstract

An improved firearm having a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays is disclosed. The passive firing pin block prevents accidental discharge when the gun is dropped. The hammer drop mechanism permits the hammer to be safely lowered when a cartridge is present in the chamber without actuating the trigger. The V-block type barrel bushing accurately repositions the forward end of the barrel relative to the sights to provide maximum accuracy. The square sight inlays allow the user to quickly and precisely aim the firearm.

Inventors:	Dornaus; Thomas F. (Norwalk, CA)
Assignee:	Voit; Richard A. (Ketchum, OH)
Appl. No.:	296278
Filed:	August 24, 1994

Current U.S. Class:	42/137; 42/144
Intern'l Class:	F41G 001/01
Field of Search:	42/100 33/233,241,242,243,252,253,254,255,256,257,258,259,260

References Cited [Referenced By]

U.S. Patent Documents

2494163	Jan., 1950	Davis	33/257.
3641676	Feb., 1972	Knutsen et al.	42/100.
Foreign Patent Documents
16044	Apr., 1904	AT	33/233.

Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Stetina Brunda & Buyan

Parent Case Text

This application is a continuation of application Ser. No. 08/079,339, filed Jun. 16, 1993, now abandoned, which is a division of Ser. No. 07/537,064, filed Jun. 12, 1990 now U.S. Pat. No. 5,245,776.

Claims

What is claimed is:

1. A sight assembly for a firearm, said sight assembly comprising:

a) a rear sight having a groove formed therein;

b) a front sight disposed forward of said rear sight;

c) two colored first indicia formed upon said rear sight such that said rear sight defines a background therefor, one of said first indicia formed upon either side of the groove in said rear sight, each first indicia defining at least one straight horizontal edge against said background;

d) one colored second indicia formed upon said front sight such that said front sight defines a background therefor, said second indicia defining at least one straight horizontal edge against said background; and

e) wherein the straight horizontal edges defined by said first indicia and the straight horizontal edge defined by said second indicia are configured to cooperate to form a single horizontal line when the firearm is aimed.

2. The sight assembly as recited in claim 1 wherein said first and second indicia comprise squares.

3. The sight assembly as recited in claim 1 wherein said first indicia and said second indicia are configured to appear approximately equal in size when the firearm is aimed.

4. The sight assembly as recited in claim 1 wherein said first indicia and said second indicia comprise inlays.

5. The sight assembly as recited in claim 1 further comprising:

a) a windage adjustment screw, said windage adjustment screw extending horizontally through a portion of the firearm and extending through said rear sight; and

b) an elevation adjustment screw, said elevation adjustment screw extending vertically through said rear sight such that rotation of said elevation adjustment screw causes said rear sight to pivot about said windage adjustment screw.

Description

FIELD OF THE INVENTION

The present invention relates generally to firearms and more particularly to an improved firearm having a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays.

BACKGROUND OF THE INVENTION

Firearms having inertial firing pins which, when struck by the hammer of the firearm, are driven forward to strike and discharge a cartridge are well known. Several devices have been proposed to selectively lock the firing pin in order to prevent the firearm from being accidentally discharged. Such accidental discharge may occur in the event that the firearm is dropped from a distance of several feet and subsequently lands in such a manner that inertia carries the firing pin forward, thus causing it to strike the cartridge.

Manual firing pin locks are well known. They are typically located within the slide of an automatic or semiautomatic pistol and function to prevent the firing pin from contacting a chambered cartridge when activated. There is a tendency not to activate such manually operated firing pin lock mechanisms when it is anticipated that rapid and unexpected use of the gun may be required, e.g. during law enforcement or combat use. In such situations, the user does not want to be forced to remember to disengage the firing pin lock under stressful conditions, nor does he want to take the time to do so.

Passive firing pin locks such as that described in U.S. Pat. No. 4,555,861 issued to Khoury are known. Such devices have the advantage of not requiring the user to manually engage and disengage the lock. Rather, the lock is automatically engaged when the trigger is in the non-depressed or unactuated position and is automatically disengaged when the trigger is in the depressed or actuated position.

Prior art passive firing pin locks such as the Khoury device suffer, however, from the inherent deficiency that the firing pin is necessarily free to travel forward any time the trigger is depressed, including during the chambering of a cartridge. In such firearms, a malfunction of the disconnector or sear can cause a normally semiautomatic gun to function in a fully automatic mode. A semiautomatic firearm discharges one cartridge each time the trigger is pulled. A fully automatic firearm continues to fire as long as the trigger is depressed and cartridges remain to be fired. Unexpected fully automatic operation could result in the firearm being discharged in an inappropriate direction, possibly resulting in injury or death. Since fully automatic operation requires a stronger grip on the firearm and a firm stance to maintain control of the firearm.

Additionally, since in the Khoury device the firing pin lock does not re-engage the firing pin until the trigger is released, it is possible that an accidental discharge could occur prior to releasing the trigger. For example, in a combat environment the firearm could be struck by a bullet or shrapnel immediately after the firearm has been fired but prior to releasing the trigger. During this time the passive firing pin lock of the Khoury device would be inactive and therefore would not function to prevent the firing pin from being driven forward and discharging the weapon. Therefore, it is possible that an accidental discharge could occur. Also, it is conceivable that the user could fall and permit the firearm to strike a hard surface prior to releasing the trigger, thus driving the firing pin forward and accidentally discharging the firearm.

It would therefore be desireable to lock the firing pin in a retracted position at all times except when it is explicitly desired that the firearm be discharged. This would prevent both unexpected fully automatic operation and accidental discharge.

Also, such contemporary passive firing pin locks are comparatively complex in their structure. The Khoury device is typical in this regard and includes a double lever and pin arrangement which is comparatively prone to malfunction due to excessive wear, contamination, or breakage. It would therefore be desirable to provide a mechanically simpler mechanism for preventing undesired forward motion of the firing pin.

Double action semi-automatic pistols are also well known in the art. Pulling the trigger of a double action pistol both cocks the hammer and causes it to fall upon the firing pin. This eliminates the need to separately cook the hammer prior to pulling the trigger. Thus, double action pistols are more effective when quick and unexpected use may be required.

Since the hammer of a double action semi-automatic pistol does not have to be separately cocked and the pistol is therefore capable of being fired by merely pulling the trigger, it is often desireable to keep a cartridge in the chamber. This permits rapid use of the pistol by merely aiming and pulling the trigger. To chamber a cartridge, the slide is pulled back and released, thereby stripping the top cartridge from the magazine and loading it into the chamber. This action also cocks the hammer of the pistol and leaves the hammer in a cocked position.

After chambering a cartridge, the hammer remains in a cocked position such that pulling the trigger will discharge the weapon. Various safety mechanisms are known for preventing inadvertent discharge of the firearm when the trigger is pulled while the hammer is in a cocked position. Such safety mechanisms generally either prevent the sear from releasing the hammer, lock the hammer in the cocked position, or prevent the trigger from being pulled. However, as with the manual firing pin lock, the use of such a safety mechanism is often undesirable when rapid and expected use is likely.

Thus, it is often desireable to have a cartridge chambered; but due to the double action operation of the pistol, it is not necessary to maintain the hammer in a cocked position. Indeed, it is frequently more desireable to maintain the hammer in a decocked position. This is because it takes a substantially greater amount of force to depress the trigger and discharge the firearm when the hammer is in the decocked position. As such, additional force must be provided by the user to cock the hammer, instead of merely releasing it to fall upon the firing pin (i.e. it requires a much more deliberate action to depress the trigger of a decocked double action firearm than to depress the trigger of a cocked double action firearm). This additional force is necessary to overcome the hammer spring tension as the hammer is raised to the cocked position. Such additional force makes an accidental discharge less likely. For example, if a foreign object inadvertently engages the trigger, it is much less likely that an accidental discharge will occur if the hammer is decocked.

Therefore, a common problem associated with double action semi-automatic pistols is the safe lowering of the hammer after manually chambering a cartridge. It may be desired to lower the hammer, thus decocking the firearm, when the gun is to be carried in a holster, stored for an extended period of time, or when it is otherwise desireable not to have the hammer in a cocked position. Many police departments require that their officers carry their firearm with a cartridge in the chamber and the hammer in a decocked position.

A common method for decocking a firearm is to grasp the hammer with the fingers of one hand while holding the firearm in the other hand and pulling the trigger. Grasping the hammer prevents it from falling forcefully upon the firing pin and thus discharging the gun. However, occurrences of inadvertent discharges while attempting this procedure are not uncommon. Since such inadvertent discharges can cause injury and death, it is very desireable to provide a means for lowering the hammer of such a firearm in a safe and convenient manner.

Various decocking or hammer drop mechanisms are known. One such mechanism slowly lowers the hammer to its decocked position such that the hammer does not strike the firing pin with enough force to drive the firing pin into the chambered cartridge. Another mechanism rotates a portion of the firing pin out of the path of the falling hammer such that the hammer cannot strike the end of the firing pin. In this instance the trigger may be pulled to cause the hammer to drop, since it is prevented from striking the displaced firing pin. Alternatively, the mechanism which displaces the portion of the firing pin may also cause the hammer to drop.

A means for lowering the hammer in a single action semi-automatic pistol would likewise be desireable since it is often desired to maintain a single action semi-automatic pistol with a chambered cartridge. This is true even though the hammer of a single action pistol must be separately cocked prior to firing the first cartridge.

Additionally, in the prior art, much weight has been given to the ability of the barrel bushing to firmly secure the front end of the barrel in position. The accuracy of the firearm depends upon the repeatability with which the barrel can be repositioned relative to the sights.

Various bushings for repositioning the forward end of the barrel after each shot are well known. The simplest of such bushings merely receive the front end of the barrel, holding it in place until the firearm is discharged. During discharge, the bushing travels rearward along the barrel. When the barrel unlocks from the slide, the bushing permits slight rotation of the barrel relative to the slide. Such rotation is necessary to accommodate the unlocking/locking motion of the barrel. Such simple bushings must therefore incorporate a slightly oval, elongated, or oversized central aperture.

Through the use of close tolerances, an attempt is made to securely restrain the forward end of the barrel within the bushing prior to discharging the firearm. The requirement for such close tolerances causes the firearm's accuracy to degrade as the bushing wears and the tolerances are lost. Also, close tolerances require the mechanism be maintained comparatively free from contamination. Dirt, sand, lint, and other contaminants can cause the bushing to bind upon the barrel and jam the firearm. The use of close tolerances increases the rate at which the barrel bushing wears due to friction. Fabrication of barrel bushings having close tolerances is comparatively difficult and expensive.

Thus, the prior art has concentrated efforts for achieving superior accuracy upon the ability of the barrel bushing to firmly secure the forward end of the barrel in position. Other mechanisms, such as Colt's collet type barrel bushing, disclosed in U.S. Pat. No. 3,564,967 issued to La Violette have been used to achieve this result. All such methods of firmly securing the forward end of the barrel in position are characterized by the requirement for closely held tolerances which tend to degrade over time and thus cause the firearm's accuracy to deteriorate.

Another common problem with prior art bushings is cracking due to the repeated application of stress when the gun is fired. This is particularly true of the Colt collet type bushing wherein comparatively delicate fingers secure the barrel in place. Such fingers are subject to the development of stress cracks. Consequently, they occasionally break off whereupon they may cause the gun to jam.

It would be desirable to repeatably position the barrel without requiring that the forward end of the barrel be firmly secured in place. It would also be desireable to eliminate the need for close tolerance in the fabrication of barrel bushings. Additionally, it would be desireable to provide a barrel bushing which is not susceptible to malfunction due to stress.

In addition, colored inlays formed upon the front and rear sights of firearms for aiding the user in the aiming process are well known. Typically a single round or rectangular inlay is provided upon the firearms front sight and two round inlays are provided on either side of the central groove of the rear site. Such inlays are typically colored either white or red to provide a stark contrast to the deep blue or black color of the gun sights. The use of colored inlays provides highly visible reference points by which the user can quickly align the sights upon a target.

Such inlays are used by aligning the inlay formed upon the front sight between the two inlays formed upon the rear sights. This process is hastened by the ease with which the colored inlays are perceived by the user. The red or white inlays can be quickly spotted and rapidly brought into rough alignment.

However, precise alignment of the prior art inlays is relatively difficult. The curved peripheries of the round inlays used upon the rear and/or front sights do not provide an easy means for judging alignment. In the prior art, the user must either align round rear inlays to a round front inlay or round rear inlays to a rectangular front inlay.

As will be recognized, it is difficult to align curved lines to each other or to a straight line. The curved lines do not provide a single reference for alignment, but rather present the user with the task of defining a reference. The user must align the round inlay by concentrating upon some portion thereof. For example, the user may attempt to visually determine the center point of the round inlay on the front sight and align it to similarly determined center points on round inlays of the rear sights.

Thus, although prior art firearms have proven generally suitable for their intended purposes, they possess inherent deficiencies which detract from their safe use and reduce accuracy below that theoretically obtainable. This detracts from their overall effectiveness in the marketplace.

In view of the shortcomings of the prior art, it is desirable to provide an improved firearm having a trigger actuated passive firing pin lock, a convenient and safe means for lowering the hammer of a firearm having a chambered cartridge, a barrel bushing which accurately repositions the forward end of the barrel relative to the sights, and sight inlays which allow the user to quickly and precisely aim the firearm.

SUMMARY OF THE INVENTION

The present invention specifically addresses and alleviates the above mentioned deficiencies associated in the prior art. More particularly, the present invention comprises an improved firearm having one or more safety and performance features such as a passive firing pin lock, a hammer drop mechanism, a V-block type barrel bushing, and square sight inlays.

The passive firing pin lock of the present invention prevents an accidental discharge when the gun is dropped. The passive firing pin lock is comprised of a lever which engages the firing pin and locks the firing pin in position such that the firing pin cannot travel forward and discharge a chambered cartridge. The lever pivots about a pin between an engaged or safe position and a disengaged or fire position. The lever is biased in the safe position by a spring.

Pulling the trigger rotates the sear to disengage a catch formed upon the sear from a notch formed upon the hammer and thus permits the hammer to fall. Prior to rotating sufficiently to cause the hammer to fall, a pawl formed upon the sear engages a tab formed upon the passive firing pin lock lever, thus causing the lever to disengage the firing pin. This places the lever in the fire position wherein further rotation of the sear will cause the hammer to drop upon the firing pin and drive the firing pin forward, thus discharging the firearm.

Upon ignition of the propellant contained within the cartridge, the firing pin is immediately urged rearward by both the firing pin spring and a dynamic impulse imparted as gas pressure tends to re-flatten the primer. Upon retraction to its original position, the firing pin is immediately locked into place by the passive firing pin lock lever. This occurs prior to the user releasing the trigger. Thus, the firing pin is immediately locked into a safe position and the gun is thereby protected from accidental discharge.

By immediately locking the firing pin in a safe position, prior even to releasing the trigger, the probability of an accidental discharge is substantially reduced. For instance, if the gun should be forcibly struck, i.e. by a bullet or shrapnel, immediately after a shot has been fired, but prior to releasing the trigger, the firing pin will have been locked in a safe position and the gun will be prevented from discharging. Also, in the event that the user falls after firing a shot but prior to releasing the trigger, and the gun strikes a hard surface with sufficient force to drive the firing pin forward, the gun is again prevented from discharging.

The manufacture of a pistol having the passive firing pin lock of the present invention essentially involves the fabrication of a lever and a modification of the sear. By contrast, manufacture of the Khoury device involves the fabrication of two separate lever mechanisms and a pin lock. Thus, manufacture of the firing pin lock of the present invention involves fewer materials, less machining, and simplified assembly. This provides a substantial savings in manufacturing costs.

Additionally, locking of the firing pin in the safe position without the necessity of the trigger being released precludes the possibility that the pistol could operate in the fully automatic mode in the event of a sear or disconnector malfunction. Operation of the firearm in the fully automatic mode is extremely dangerous since it typically occurs unexpectedly and results in the rapid discharge of several cartridges. In the event of such an occurrence the user often does not maintain full control of the firearm since the discharge of more than one cartridge is not expected. Therefore, several shots could be fired in an unsafe direction, resulting in death or injury. The ability to lock the firing pin in place immediately without the necessity of releasing the trigger therefore reduces the likelihood of such an occurrence.

The passive firing pin lock of the present invention is also particularly well suited for use in a double action only firearm. While most double action firearms can be operated in either a double action or single action mode, double action only firearms can only be fired in a double action mode. Double action only firearms do not have a hammer notch and sear catch for holding the hammer in a cocked position and must therefore be fired from the decocked position, i.e. in a double action mode.

In a double action only firearm it is often desired that the weapon be as simple to operate as possible. Thus, external manually operated safeties are not desirable. It is usually intended that such firearms be capable of being used by merely aiming and pulling the trigger.

Since the hammer of a double action only firearm does not remain in a cocked position after firing, it follows the slide forward as the next round is chambered. The hammer thus pushes the firing pin slightly forward as the slide moves into battery. Therefore, the firing pin may actually contact the primer of a chambered cartridge as the slide is brought into battery. While the firing pin does not strike the primer with sufficient force to cause the firearm to discharge, it is nevertheless undesirable to permit the firing pin to contact the primer except when a discharge is intended.

The passive firing pin lock of the present inventory prevents the firing pin from contacting the primer of a chambered round as the slide is brought into battery. This adds an extra margin of safety to the firearm. The firing pin cannot contact the primer since the firing pin is locked into a retracted position as the slide travels rearward and remains locked as the slide moves forward into battery.

The passive firing pin lock of the present invention thus provides a means whereby a double action only firearm may be constructed without the need for an externally operated manual safety and without permitting the firing pin to contact the primer of a chambered round as the slide moves into battery after the round is chambered.

In addition, the present invention incorporates a novel hammer drop mechanism which permits the hammer to be safely lowered when a cartridge is present in the chamber. This is accomplished without touching the trigger of the firearm. The hammer drop mechanism is comprised of first and second hammer drop shafts which are inserted into the slide at diametrically opposed positions and connect to form a single shaft having three cam surfaces formed thereupon. An external thumb lever formed upon one of the shafts permits the shaft to be manually rotated by the user. Rotation of the shaft engages two of the cams against the firing pin, thus withdrawing the firing pin beyond the firing pin retainer and into the slide such that the hammer can no longer strike the firing pin. Further rotation of the shafts cams a hammer drop push rod downward against the sear, thus causing the sear to rotate and release the hammer.

The use of two cams to withdraw the firing pin provides redundancy such that the firing pin will be safely retracted in the event of excessive wear or malfunction of one of the cams. Thus, even if one cam fails, the firing pin will still be retracted within the slide prior to the hammer falling.

Therefore, in operation the hammer drop mechanism of the present invention first repositions the firing pin within the slide to prevent contact with the hammer and then actuates the hammer causing it to fall to a decocked position. The hammer drop mechanism of the present invention thereby provides a safe and convenient means for a user to lower a semi-automatic pistol's hammer when a cartridge is chambered.

A V-block type barrel bushing of the present invention accurately repositions the forward end of the barrel relative to the sights to provide maximum accuracy. The V-block type barrel bushing of the present invention is comprised of two flat contact surfaces formed as an integral part of the slide and configured to contact the front end of the barrel tangentially at two locations. The use of such a V-block provides an extremely accurate means for repeatably positioning a cylindrical object. Thus, in the same manner that a machinist might axially position a section of bar stock prior to drilling, the forward portion of the barrel is precisely positioned prior to discharging the pistol.

Since the V-block bushing of the present invention does not attempt to firmly secure the front end of the barrel in place but rather repeatedly locates the front end of the barrel in a consistent position relative the slide, friction is minimized and bushing failure is eliminated. Also, the requirement for close tolerance machining is eliminated since the exact positioning and dimensions of the V-block are unimportant. It is merely necessary that the two contact surfaces be formed at approximately the five and seven o'clock positions and be tangential to the barrel. Use of the V-block barrel bushing of the present invention therefore provides the best accuracy theoretically possible while eliminating the prior art problems of wear and malfunction.

Further, the present invention discloses the use of square sight inlays or indicia. The square sight markings of the present invention are preferably comprised of a single square inlay formed upon the front sight and one square inlay formed upon either side of the groove in the rear sight. The square inlays are positioned such that when all three of their upper and lower edges are aligned and the square inlay formed upon the front sight is centered between the square inlays formed upon the rear sights, then the gun is on target. The advantages of such square inlays lie in the ability to rapidly align their upper and lower edges and the ability to perceive very small discrepancies in alignment.

It is a simple matter for the user to vary the elevation of the gun to achieve alignment of the upper and lower edges of the square inlays. The user simply concentrates upon either the upper or lower edges of the square inlays and tilts the gun to bring them into alignment. When aligned, both the upper and lower edges of the square inlays form a pair of single lines such that any deviations in the alignment of the inlays is immediately apparent and can be corrected.

Alignment of sights having round inlays is far more difficult by comparison. There are no straight lines for the user to bring into alignment. Therefore the user must rely upon his ability to perceive corresponding points within each round inlay and attempt to align these imagined corresponding points. For example, the user may concentrate upon aligning the centers of the round inlays. This is extremely difficult since the centers are only defined within the user's mind and are therefore extremely difficult to align with any precision. The user may also attempt to align the sights by concentrating upon the uppermost portion of the outer perimeter of each round inlay. This is likewise extremely difficult since the precise location of the uppermost point of the perimeter of each round inlay again exists only within the user's mind. The user must therefore attempt to determine the precise location of either the center, uppermost portion of the perimeter, or some other distinctive portion of each round inlay and do this subconsciously while also aligning the sights upon the target.

Aligning the square inlay sights of the present invention in azimuth is also greatly simplified over contemporary round inlays. In the present invention it is simply necessary to insure that the front sight square inlay is centered between the two rear sight square inlays by rapidly providing an equal distance between each of the two rear sight square inlays and the front square inlay. This is a simple matter since the user is aligning straight vertical lines. That is, it is a simple matter to visually determine the distance between vertical straight lines. By contrast, it is far more difficult to determine the distance between adjacent circular edges. In order to determine the distance between adjacent circular edges, it is first necessary to imagine points upon each of the circular edges from which the determination is to be made. Thus, the user must again use judgement to form an imaginary point upon the circumference of each of the round inlays and to form a mental measurement therebetween.

As such, the square sight inlays of the present invention provide a means of rapidly and accurately aligning the sights upon a target without having to rely upon the user's ability to mentally measure distances between curved objects. The square sight inlays thus allow the user to quickly and precisely aim the firearm.

These, as well as other advantages of the present invention will be more apparent from the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the right side of a semi-automatic pistol in accordance with the preferred embodiment of the present invention;

FIG. 2 is a perspective view of the left side of the semi-automatic pistol of FIG. 1;

FIG. 3 is a perspective view of the passive firing pin lock of the present invention showing the sear, sear housing, passive firing pin lock lever, and the firing pin, the firing pin being shown in the phantom, and the passive firing pin lock lever being shown partially in phantom;

FIG. 4 is an exploded view of the sear housing, sear, passive firing pin lock lever, and firing pin of FIG. 3;

FIG. 5 is a perspective view of the sear, passive firing pin lock lever, and a portion of the firing pin of FIG. 4;

FIG. 6 is a sectional view of the sear and a portion of the passive firing pin lock lever taken along line 6--6 of FIG. 5;

FIG. 7 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1;

FIG. 7A is an enlarged cross-sectional side view of the rear portion of the slide and receiver shown in FIG. 7 depicting the hammer in its cocked position, the sear engaging the hammer, and the passive firing pin lock lever positioned to block the forward motion of the firing pin;

FIG. 8 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the hammer in the cocked position, the sear disengaged from the hammer, and the passive firing pin lock lever disengaged from the firing pin;

FIG. 9 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the hammer in the decocked position, the sear disengaged from the hammer, the passive firing pin lock lever disengaged from the firing pin, and the firing pin in its forward most position;

FIG. 10 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 depicting the slide in its rear most position, the hammer in its cocked position, the passive firing pin lock lever engaging the firing pin, and the sear engaging the hammer;

FIG. 11 is an exploded perspective view of the hammer drop mechanism of the present invention showing the first and second hammer drop shafts, the rear most portion of the firing pin, the hammer drop push rod, and a portion of the sear;

FIG. 11A is a cross-sectional view of the first and second hammer drop shafts taken along line 11A of FIG. 11 and a roll pin used to attach them together;

FIG. 12 is a perspective view of the second hammer drop shaft, the hammer drop push rod, and a portion of the sear of FIG. 11 showing the cam formed upon the second hammer drop shaft for camming the hammer drop push rod against the sear;

FIG. 13 is a sectional perspective view of a portion of the firing pin of FIG. 11 showing the two camming surfaces upon which the two cams formed upon the first and second hammer drop shafts act;

FIG. 14 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever in the horizontal or unactuated position;

FIG. 14A is an enlarged cross-sectional view of the hammer drop push rod cam engaging the hammer drop push rod as shown in FIG. 14;

FIG. 14B is an enlarged cross-sectional view of the first firing pin cam about to engage the first firing pin camming surface of the firing pin as shown in FIG. 14;

FIG. 14C is an enlarged side view of the second firing pin cam about to engage the second firing pin camming surface as shown in FIG. 14, the second firing pin camming surface being shown in dashed lines;

FIG. 15 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever depressed to a position approximately midway in its travel;

FIG. 15A is an enlarged cross-sectional side view of the hammer drop push rod cam engaging the hammer drop push rod as shown in FIG. 15;

FIG. 15B is an enlarged cross-sectional side view of the first firing pin cam engaging the first firing pin camming surface of the firing pin as shown in FIG. 15;

FIG. 15C is an enlarged side view of the second firing pin cam engaging the second firing pin camming surface of the firing pin as shown in FIG. 15;

FIG. 16 is a cross-sectional side view of the rear portion of the slide and receiver of the pistol of FIG. 1 showing the hammer drop mechanism of the present invention with the thumb lever in its fully depressed position;

FIG. 16A is an enlarged cross-sectional side view of the hammer drop push rod cam depressing the hammer drop push rod as shown in FIG. 16;

FIG. 16B is an enlarged cross-sectional side view of the first firing pin cam engaging the first firing pin camming surface of the firing pin as shown in FIG. 16;

FIG. 16C is an enlarged cross-sectional side view of the second firing pin cam engaging the second firing pin camming surface of FIG. 16;

FIG. 17 is a front view of the V-block bushing of the present invention formed within the slide of the pistol of FIG. 1;

FIG. 18 is a cross-sectional side view of the V-block bushing of FIG. 17;

FIG. 19 is a cross-sectional side view of the rear sight of the pistol of FIG. 1;

FIG. 20 is a cross-sectional view taken about lines 20--20 of the rear sight of FIG. 19 showing the two square inlays of the present invention;

FIG. 21 is a perspective view of the front and rear sights showing the square inlays;

FIG. 22 is a rear view of the front and rear sights of FIG. 21; and

FIG. 23 is a rear view of the slide of the pistol of FIG. 1 showing alignment of the square inlays of the front and rear sights with a bull's-eye.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

The firearm of the present invention is illustrated in FIGS. 1-23 which depict a presently preferred embodiment of the invention. Referring now to FIGS. 1 and 2, a pistol 10 in accordance with the present invention is comprised generally of a receiver 24 and a slide 22 disposed for reciprocal motion upon the receiver 24. A trigger 12 protrudes from the lower portion of receiver 24 to actuate, through conventional internal mechanisms, a hammer 14. A manually operated safety 25 prevents the trigger 12 from discharging the pistol 10 as in the prior art. As is well known, when trigger 12 is actuated, the hammer 14 strikes firing pin striking surface 54 and firing pin retainer 28. Rear 18 and front 20 sights provide for the alignment of barrel 30 with a target. In the preferred embodiment, the pistol 10 comprises a semi-automatic handgun, such as that depicted in U.S. Pat. No. 4,726,136 issued to Dornaus et al. the disclosure of which is expressly incorporated herein by reference. In this regard, the present invention comprises a specific improvement over the hand gun disclosed in U.S. Pat. No. 4,726,136 but is additionally applicable to other types of firearms.

Referring now to FIGS. 3 through 6, the passive firing pin lock of the preferred embodiment of the present invention is depicted. A sear 32 is pivotally disposed within sear housing 36. Sear housing 36 is disposed within the receiver of FIGS. 1 and 2 proximate the hammer 14. The sear 32 pivots about sear pin 34. An arm 48 extends from the sear 32 and has a pawl 50 formed upon the distal end thereof.

Passive firing pin lock lever 38 is pivotally mounted within the slide 22 above the sear 32. Lever 38 pivots about lever pin 41 (shown in FIG. 7 and 7A) which extends through aperture 40 formed in lever 38. Lever 38 has a detent 42 formed upon one end thereof. A tab 46 extends perpendicularly from approximately the middle of the lever 38. A contact surface 52 is formed upon the upper surfaces of the tab 46.

An inertial firing pin 26 is disposed within the slide 22 immediately above the passive firing pin lock lever 38. The firing pin 26 has a recess 44 formed in the lower rear surface thereof and sized to receive the detent 42 formed upon the lever 38. Firing pin striking surface 54 of firing pin 26 extends through the firing pin retainer 28 as shown in FIG. 2.

In the present invention, as well as in the prior art, depression of the trigger 12 is mechanically communicated to the sear 32 via linkage (not shown), thus causing the sear to rotate to permit the hammer 14 to fall upon the firing pin retainer 28 and striking surface 54 of the firing pin 26. The firing pin 26 is thus driven forward toward the primer of a chambered cartridge, against the biasing force of a firing pin spring 62 (as shown in FIGS. 7-10). The inertia of the firing pin 26 causes it to strike the primer with sufficient force to detonate the primer, thus discharging the firearm.

Clockwise (as viewed in FIG. 3) rotation of the lever 38 engages a detent 42 within a recess 44 formed in the lower rear portion of the firing pin 26. Engagement of the detent 42 within the recess 44 of firing pin 26 thus prevents forward translation of the firing pin 26 within the slide 22. Clockwise rotation of the sear 32 causes the tab 46 formed upon lever 38 to be engaged by pawl 50 of sear 32.

As can be seen in the cross sectional view of FIG. 6, the pawl 50 formed upon the distal end of arm 48 engages contact surface 52 of tab 46 when pawl 50 moves downward in response to clockwise rotation of the sear 32. Thus, clockwise rotation of the sear 32 causes lever 38 to rotate counterclockwise, and to disengage detent 42 from recess 44 of firing pin 26. Detent 42 of the passive firing pin lock lever 38 engages the recess 44 formed within firing pin 26 at all times except when the trigger 12 is depressed to fire the pistol 10.

As in the prior art, clockwise rotation of the sear 32 disengages the hammer 14 from the sear 32 thus permitting the hammer 14 to fall and strike the firing pin 26. The firing pin 26 travels forward to discharge a chambered round in response to the striking surface 54 of the firing pin 26 being struck by the hammer 14. The detent 42 of the present invention is disengaged from the recess 44 of the firing pin 26 immediately prior to the disengagement of the hammer 14 from the sear 32.

The detent 42 is engaged within the recess 44 of the firing pin 26 at all times other than when the trigger 12 is depressed, thus effectively preventing accidental discharge of the pistol 10. Dropping of the pistol 10 with its barrel downward, such that an accidental discharge would be likely in a prior art pistol, thus does not cause the firing pin 26 to travel forward under the force of its own inertia when the firearm strikes the floor.

Operation of the passive firing pin look of the present invention is presented in further detail with reference to FIGS. 7-10 wherein the lock is depicted in its various stages of operation as the trigger 12 is pulled and the pistol 10 is discharged.

With particular reference to FIGS. 7 and 7A, the pistol 10 is depicted with the hammer 14 in a cocked position and a cartridge 66 loaded in the chamber 30. The striking surface 54 of the firing pin 26 extends beyond the firing pin retainer 28 such that the hammer 14 will contact the striking surface 54 of the firing pin 26 and drive the firing pin 26 forward toward the cartridge 66 when the hammer 14 is released. Since the trigger has not yet been depressed, detent 42 on lever 38 is received by recess 44 of firing pin 26. Thus, the firing pin 26 is locked in a safe position and thereby prevented from translating forward and striking the cartridge 66. Spring 68 disposed against surface 70 of lever 38 biases lever 38 into this safe position.

If the pistol were to be dropped while in this safe configuration, the firing pin 26 would be prevented from moving forward under its own inertia and striking cartridge 66 with the tip 64 thereof. Thus, the probability of death or injury due to accidental discharge is reduced.

The sear catch 74 of sear 32 engages the hammer notch 72 of the hammer 14, thus maintaining the hammer 14 in its cocked position until the trigger 12 is pulled. Pulling the trigger 12 at this point will rotate (through a conventional mechanical linkage which is not shown) the sear 32 clockwise, thus disengaging sear catch 74 from hammer notch 72 and permitting the hammer to rotate clockwise under the biasing of the hammer spring (not shown), whereupon the hammer 14 will strike the striking surface 54 of the firing pin 26 and the firing pin retainer 28. Pawl 50 formed upon the end of arm 48 of the sear 32 does not contact tab 46 of lever 38 when the trigger 12 is not depressed.

With particular reference to FIG. 8, the passive firing pin lock is depicted after the trigger 12 has been depressed. Depressing the trigger 12 has caused the sear 32 to rotate clockwise sufficiently to permit sear catch 74 to disengage from hammer notch 72 such that hammer 14 will begin to rotate clockwise under the urging of the hammer spring (not shown), whereupon the hammer 14 will strike striking surface 54 and firing pin retainer 28. Immediately prior to sear catch 74 disengaging hammer notch 72, pawl 50 contacts tab 46 of the lever 38 and urges tab 46 downwardly. This causes detent 42 to disengage from recess 44. Thus, as hammer 14 rotates clockwise to strike the striking surface 54 of firing pin 26, firing pin 26 is unlocked from its safe configuration and placed in a fire configuration wherein firing pin 26 is free to travel forward to cause the discharge of the pistol 10.

With particular reference to FIG. 9, hammer 14 has struck the striking surface 54 of the firing pin 26, thus driving the firing pin 26 forward against the urging of spring 62. The tip 64 of firing pin 26 thus strikes cartridge 66 to discharge the pistol 10. The pawl 50 of the sear 32 holds the lever 38 in the fire configuration as the firing pin 26 rebounds rearward under the urging of spring 62.

With particular reference to FIG. 10, the reaction to the lead bullet moving forward causes the slide 22 to rapidly recoil longitudinally rearward, thus cocking the hammer 14, extracting the expended cartridge, and permitting another cartridge to be chambered. As the slide 22 travels rearward, tab 46 of lever 38 disengages sear pawl 50, thus permitting detent 42 to be again received by recess 44 of the firing pin 26.

Therefore, firing pin 26 is once again locked into the safe configuration before slide 22 returns to its rest position. As in the prior art, sear 32 rotates counterclockwise such that sear catch 74 engages hammer notch 72 thus preventing the hammer 14 from rotating clockwise and again striking the striking surface 54 of the firing pin 26. Thus, as the slide returns to its forward most position, the safe configuration of the firing pin 26 is once again attained.

Referring now to FIGS. 11 through 13, the hammer drop mechanism of the present invention is depicted. The hammer drop mechanism is generally comprised of first 100 and second 102 shafts, the firing pin 26, hammer drop push rod 104, and sear 32. The first shaft 100 has a thumb actuation lever 106 formed upon one end thereof and a shaft recess 110 and second firing pin cam 108 formed upon the opposite end thereof. The second shaft 102 has a flat shaft portion 112, a first firing pin cam 114 and a hammer drop cam 116 formed thereupon.

First 100 and second 102 shafts are inserted into the slide 22 such that they may be attached together with pin 101 to form a single shaft which passes transversely through the slide 22 Pin 101 extends through aperture 119 in second shaft 102 and through aperture 121 in first shaft 100. Therefore, rotation of the first shaft 100 by depressing thumb lever 106 causes a like rotation of second shaft 102.

With particular reference to FIG. 12, the upper end 118 of hammer drop push rod 104 contacts the hammer drop cam 116 of second shaft 102 and the lower end 120 contacts the arm 48 of the sear 32. The flat shaft portion 112 is formed to be received by the shaft recess 110 of the first shaft 100. Thus, first shaft 100 and second shaft 102 attach together to form a single rotatable member.

With particular reference to FIG. 13, the firing pin 26 includes a first camming surface 124 and a second camming surface 122 formed thereon. The first camming surface 124 is adapted to engage the first firing pin cam 114 and the second surface 122 is adapted to engage the second firing pin cam 108.

The firing pin 26 is prevented from rotating about its longitudinal axis by the abutment of the lower surface 115 of the second shaft 102 against the upper flat surface 127 of recess 126 formed in the firing pin 26 and by the abutment of the edge 117 of the first shaft 100 against the flat side 125 of the firing pin 26.

Operation of the hammer drop mechanism of the present invention is presented in detail with reference to FIGS. 14-16C wherein the mechanism is depicted in various stages of operation as the thumb lever is depressed. Thumb lever 106 is biased in the up or unactuated position by the firing pin spring 62 acting through the firing pin 26 and by the hammer drop pin spring 105 acting through the hammer drop pin 104. Actuation of the thumb lever 106 cams the firing pin 26 into the slide 22 such that the striking surface 54 of the firing pin 26 is disposed beneath the hammer striking or outer surface 29 of the firing pin retainer 28 and consequently cannot be struck by the hammer 14. Further rotation of the thumb lever 106 actuates the sear 32, thus releasing the hammer 14 and permitting it to fall to a decocked position.

With particular reference to FIG. 14, the firing pin 26 is depicted in its rest position. The striking surface 54 of the firing pin 26 extends beyond the hammer striking or outer surface 29 of the firing pin retainer 28. The hammer drop cam 116 lightly contacts the upper end 118 of the hammer drop push rod 104. The first firing pin cam 114 is positioned almost in contact with the first camming surface 124 of the firing pin 26. The second firing pin cam 108 is positioned slightly above the second camming surface 122 of the firing pin 26. The hammer 14 is shown in the cocked position and maintained therein by the sear 32.

The hammer drop push rod 104 is disposed intermediate the second shaft 102 and the sear 32 such that rotation of the second shaft 102 in a clockwise direction by manipulation of the lever 106 will cause the hammer drop cam 116 to abut the uppermost end 118 of the hammer drop push rod 104 and translate the lower end 120 of the hammer drop push rod 104 downwardly against the bias of hammer drop push rod spring 105 into contact with the arm 48 of the sear 32. Continued rotation of the second shaft 102 in the clockwise direction rotates the arm 48 of the sear 32 downward, thus causing the sear catch 74 of the sear 32 to disengage the hammer notch 72 of the hammer 14. This permits the hammer 14 to rotate clockwise under the urging of the hammer spring (not shown). The three camming actions are discussed and illustrated in greater detail with respect to FIGS. 14A-14C.

With particular reference to FIG. 14A, when the thumb lever 106 is in the horizontal or rest position as in FIG. 14, the hammer drop cam 116 abuts the upper end 118 of the hammer drop push rod 104 without urging the hammer drop push rod 104 downward. That is, the upper end 118 of the hammer drop push rod 104 contacts the hammer drop cam 116 of the second hammer drop shaft 102 under the urging of hammer drop push rod spring 105 and there is no downward force upon the hammer drop push rod 104.

With particular reference to FIG. 14B, with the thumb lever 106 in the horizontal or rest position as in FIG. 14, the first firing pin cam 114 is positioned almost in contact with the first camming surface 124 of the firing pin 26 without urging the firing pin 26 forward.

With particular reference to FIG. 14C, with the thumb lever 106 in the horizontal or rest position as in FIG. 14, the second firing pin cam 108 does not contact the second camming surface 122 of the firing pin 26.

Referring now to FIGS. 15-15C, the positions and interactions of the various components of the hammer drop mechanism of the present invention are shown when the thumb lever 106 has been rotated clockwise through approximately one half of its travel i.e. approximately 30 degrees from its initial at rest position of FIGS. 14A-14C. Rotating the thumb lever 106 to an intermediate position brings the hammer drop cam 116 firmly into contact with the upper end 118 of the hammer drop push rod 104. The hammer drop push rod 104 may translate downward slightly, but not sufficiently to cause rotation of the sear 32. Such rotation of the thumb lever 106 also causes first 114 and second 108 firing pin cams to begin camming the firing pin 26 forward such that the firing pin 26 is partially withdrawn into the slide 22.

In this position, the striking surface 54 of the firing pin 26 is approximately flush with the outer surface 29 of the firing pin retainer 28. Therefore, the firing pin 26 is withdrawn to a point where the dropping hammer 14 is incapable of driving the firing pin 26 forward to discharge the pistol 10. The firing pin 26 is withdrawn in this manner prior to initiating the process of disengaging the sear 32 from the hammer 14. That is, the hammer is prevented from falling upon the striker plate 28 until the firing pin 26 is well beneath the outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 15A, with the thumb lever 106 in an intermediate position as in FIG. 15, the hammer drop cam 116 is brought into firm contact with the upper end 118 of the hammer drop push rod 104 such that slight pressure begins to be applied to the arm 48 of the sear 32. The hammer drop cam 116 has not yet begun to urge hammer drop push rod 104 appreciably downward. Thus, the sear 32 does not yet begin to rotate clockwise and the sear catch 74 consequently firmly engages hammer notch 72 of the hammer 14.

With particular reference to FIG. 15B, with the thumb lever 106 in an intermediate position as in FIG. 15, first firing pin cam 114 has urged firing pin 26 forward sufficiently to bring the striking surface 54 of the firing pin 26 approximately flush with the outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 15C, with the thumb lever 106 in an intermediate position as in FIG. 15, second firing pin cam 108 provides a redundant means for urging firing pin 26 forward as thumb lever 106 is depressed. Second firing pin cam 108 abuts camming surface 122 formed upon firing pin 26 to simultaneously urge firing pin 26 forward in concert with cam 114 and camming surface 124. The redundant camming action assures that the striking surface 54 of the firing pin 26 is safely withdrawn into the slide 22 prior to dropping of the hammer 14. Thus, even in the event of wear or malfunction of one of the first 114 and second 108 firing pin cams and/or their corresponding camming surfaces 124 and 122, a safe means for lowering the hammer is maintained.

Referring now to FIGS. 16-16C, the position of the hammer drop mechanism as the thumb lever 106 is rotated through its full travel i.e. approximately 60 degrees from its initial at rest position of FIG. 14A-14C is depicted. As the thumb lever 106 nears the completion of its travel to the fully clockwise rotational position, the striking surface 54 of the firing pin 26 is withdrawn well below the outer surface 29 of the firing pin retainer 28 and the sear catch 74 disengages the hammer notch 72, thus allowing the hammer 14 to fall to a decocked position.

With particular reference to FIG. 16, the hammer has dropped from its cocked position and rests upon the firing pin retainer 28. With the thumb lever 106 in its fully rotated position the firing pin 26 is cammed forward such that the striking surface 54 thereof is disposed within the firing pin retainer 28 and cannot be contacted by the hammer 14 as the hammer 14 falls. The hammer 14 is prevented from striking the firing pin 26 and thereby discharging the pistol.

Thumb lever 106 and the rotatable member comprised of first 100 and second 102 shafts thus provide a single or common means for withdrawing the firing pin 26 and lowering the hammer 14. The three camming actions are discussed and illustrated in greater detail with respect to FIGS. 16A-16C.

With particular reference to FIG. 16A, it can be seen that the hammer drop cam 116 has urged the hammer drop push rod 104 against the urging of hammer drop push rod spring 105 fully to its lowermost position wherein the hammer drop push rod 104 has urged the sear 32 to rotate in a clockwise direction, thereby disengaging the sear catch 74 from the hammer notch 72.

With particular reference to FIG. 16B, with the lever 106 fully depressed as in FIG. 16 the first firing pin cam 114 has urged the firing pin 26 forward sufficiently to withdraw the striking surface 54 of the firing pin 26 beyond the hammer striking or outer surface 29 of the firing pin retainer 28.

With particular reference to FIG. 16C, with the thumb lever 106 fully depressed as in FIG. 16, in redundant fashion the second firing pin cam 108 has urged the firing pin 26 forward. The redundant operation of the first 114 and second 108 firing pin cams insures that the firing pin 28 is safely withdrawn beyond the hammer striking or outer surface 29 of the firing pin retainer 28 before the hammer 14 is released by the sear 32 to strike the firing pin retainer 28. Thus, the hammer 14 is safely decocked without discharging the pistol 10.

In addition to the improved safety features obtained by the present invention's use of the passive firing pin lock mechanism and hammer drop mechanism, the present invention provides improved performance characteristics by use of a V-block bushing and square front and rear sight system. Referring more particularly to FIGS. 17 and 18, the V-block bushing feature of the present invention is illustrated. As is conventional, the distal end of the slide 22 is provided with a bushing 55 which is threadingly inserted or press fit therewithin. The purpose of the bushing is to maintain the distal end of the barrel which is disposed within the interior of the slide 22 and position the distal end of the barrel at a repeatable location relative the slide 22 prior to discharge of pistol 10.

In contrast to prior art bushings, the bushing 55 of the present invention comprises a V-block bushing having a pair of tangential flats 56 formed adjacent its lower periphery adapted to tangentially contact the exterior diameter of the barrel 31. As best shown in FIG. 17, with the barrel 31 disposed in its fire position the exterior of the barrel 31 contacts the flats 56 formed on the V-block bushing 55 to axially center the barrel 31 relative the bushing 55 and thus the slide 22. Due to the barrel 31 being pivotally connected to the slide adjacent its opposite end and is thereby urged downwardly upon the flats 56 by lever action, the lower diameter of the barrel 31 contact the flats 56 at two tangential points, i.e. contact points 58 as indicated in FIG. 17.

As such, during movement of the slide 22 relative to the barrel 31, as during chambering of a cartridge within the barrel, upon the barrel 31 returning to its final position relative the slide 22, the barrel 31 is consistently and repeatably positioned at the same axial and vertical position relative the slide 22. Due to this repeatability, accuracy and discharge of the pistol 10 is effectuated merely by proper adjustment of the sight system of the pistol 10.

In FIGS. 19 through 23, the improved sight system of the present invention is depicted. As will be recognized, the sight system comprises a rear sight assembly 18 disposed within a recess 128 formed on the rear end of the slide 22 and a front sight 20 disposed on the opposite or front end of the slide 22 as best seen in FIGS. 1 and 2.

Referring now to FIGS. 19 through 21, the square inlay rear sight 18 of the present invention is depicted. One square inlay 76 is formed upon either side of the sight groove 78. The rear sight 18 is adjusted for elevation by turning elevation adjustment screw 80 to cause the rear sight 18 to pivot about windage adjustment screw 82 against the biasing of rear sight spring 84. Windage adjustment screw 82 secures rear sight 18 within recess 128 formed in slide 22.

Windage is adjusted by turning windage adjustment screw assembly 82 from the right side. Windage adjustment screw assembly 82 is comprised of screw 83 and slotted nut 85 such that a screwdriver can engage the windage adjustment screw assembly 82.

First ball detent 86 is urged outward by spring 87 to engage recesses 88 formed within the rear sight 18 and locks elevation screw 80 in position. A similar ball detent 90 is urged outward by spring 91 and is received by similar recesses 92 to lock windage screw 82 in position.

As shown in FIG. 21, the square inlay front sight 20 of the present invention has a single square inlay 84 formed upon its rear surface. The front sight 20 is secured to the slide 22 using two posts 86. The posts 86 are received within complimentary apertures formed within the slide 22 and the posts are peened to form flared ends 87 which secure the posts 86 therein as shown in FIG. 18.

Each square indicia inlay 76 or 84 is preferably formed by first forming a shallow square recess where the inlay is to be located. The recess is then filled with red or white epoxy, enamel, or other durable colored material. Those skilled in the art will recognize that other processes of forming the inlays are likewise suitable. Additionally, those skilled in the art will recognize that the square markings or indicia may simply be affixed upon the sights 18 and 20 as opposed to being inlayed or recessed therein.

Referring now to FIG. 22 and 23, operation of the rear 18 and front 20 sights is depicted. In use, the upper and lower straight edges of the square inlays 76 and 84 are aligned to lie within a pair of straight lines A and B, thus aligning the pistol 10 in elevation. The vertical lines of the square inlays 76 and 84 are aligned such that equal distances C and D are achieved between the front sight inlay 84 and the two rear sight inlays 76. Alignment of the rear 18 and front 20 sights with a bull's-eye 130 is shown in FIG. 23. Such alignment can be rapidly and accurately obtained due to the ease with which straight lines can be visually aligned. It is a relatively simple matter to judge when the upper surfaces, for instance, of each square inlay 76 and 84 form a single straight line A. It is also relatively simple to judge the distances between adjacent inlays such that equal spacing of C and D is achieved.

Rear 76 and front 84 inlays are sized such that they appear approximately equal in linear dimensions to the user. That is, the front square inlay 84 is sized slightly larger than the two rear square inlays 76 so that when viewed in perspective by the user the more distant front square inlay 84 appears approximately equal in size to the closer rear inlays 76. This, of course, is most important when using the square inlays of the present invention upon a rifle wherein the distance between the front and rear sights is substantial.

While squares having four straight edges are depicted for each inlay 76 and 84, those skilled in the art will recognize that only the inboard vertical edges of rear sight inlays 76 and both vertical edges of front sight inlay 84 as well as either the top or bottom horizontal edges of all three inlays 76 and 84 need to be straight. This permits the definition of line A or B and distances C and D.

It is understood that the exemplary firearm described herein and shown in the drawings represents only a presently preferred embodiment of the invention. Indeed, various modifications and additions may be made to such embodiment without departing from the spirit and scope of the invention. For example, the lever of the passive firing pin lock could engage the firing pin in a variety of different ways. Also, various hammer drop mechanism configurations are possible for withdrawing the firing pin prior to actuating the sear and causing the hammer to fall. Additionally, the V-block barrel bushing may be formed as a separate removable element rather than as an integral portion of the slide as described. Additionally, the sight inlay of the present invention need not be square, but rather may use a variety of different shapes which provide straight horizontal and/or vertical surfaces which may be quickly and accurately aligned. Thus, these and other modifications and additions may be obvious to those skilled in the art and may be implemented to adapt the present invention for use in a variety of different applications.

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