Adjustable trigger shoe

Sept. 21, 1965

3,206,884

V. C. PURVIS

ADJUSTABLE TRIGGER SHOE

Filed April 10, 1964

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J.

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INVENTOR.

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United States Patent Office

3,206,884

Patented Sept. 21, 1965

3,206,884 ADJUSTABLE TRIGGER SHOE

Vinson C. Purvis, P.O. Box 6792, Stanton, Calif.

Filed Anr. 10,1964, Ser. No. 358,826

Claims. (CI. 42—69) ⁵

My present invention relates to a firearm trigger mechanism, and more particularly relates to a trigger attachment for providing trigger adjustability which can be installed on a trigger of the firearm without dismantling ¹⁰the trigger assembly or firearm.

The accuracy of firearms equipped with double action trigger mechanisms is diminished by both trigger slack, the distance the trigger travels before it contacts the receiver and trigger travel, the distance the trigger travels ¹⁵in lowering the sear to release the cocking piece. Backlash, the distance the trigger travels after firing can also reduce the accuracy of a shot. Heretofore, it has been proposed to reduce the trigger slack by providing an attachment to the trigger which engages the sear or another ²θ member of the trigger assembly and which attachment holds the trigger cam into engagement with the receiver and in some cases exerting a force on the trigger to partially lower the sear and thereby reduce trigger travel. Such an attachment is shown in the Hoard Patent No. ²⁵2,549,904. These prior art trigger adjusting means, however, require disassembly of the trigger mechanism of the firearm to permit attachment of the adjusting means to the trigger, or the replacement of the trigger with a modified trigger. The prior art adjusting means were ³θ usually attached to a member of the trigger assembly by welding which presents additional problems inherent in repairing a tempered metal precision instrument by welding. In addition, the prior art trigger adjusting means generally required removal of the trigger mechanism for ³⁵adjustment of the trigger adjustment which normally results in changing the point of impact of the bullet on the target unless the same exact tension can be put on the guard screws when they are replaced as the firearm is reassembled. Consequently, consistent accuracy with such prior art devices was very difficult to obtain.

It is, therefore, an object of my present invention to provide a readily installable device for firearm trigger adjustability.

It is also an object of my present invention to provide ⁴⁵a firearm device which will permit adjustment of the trigger without dismantling the trigger assembly or removal of the trigger assembly from the firearm.

It is also an object of my present invention to provide a trigger shoe equipped with trigger adjusting means for ⁵⁰removing trigger slack and trigger travel.

Other objects and a more complete understanding of my present invention will become apparent by reference to the following specification and the appended claims when taken in conjunction with the drawings, wherein: ⁵

FIG. 1 shows in partial section, a double action trigger mechanism with a device embodying my present invention attached thereto;

FIG. 2 shows an enlarged elevational rear view of the trigger shoe attached to the finger piece of FIG. 1; ^ϋ '

FIG. 3 shows an elevational view of a firearm trigger guard and finger piece with a modified form of my present invention attached thereto;

FIG. 4 shows, in elevation, a modification of the adjustable trigger shoe of my present invention; ^J'⁵

FIG. 5 shows a rear view of the modified trigger shoe shown in FIG. 4.

With reference to the drawings generally, FIG. 1 shows an embodiment of my present invention installed on a trigger mechanism 10 within a firearm trigger guard ‘° 12. The device shown is a trigger shoe modified accord2 ing to the present invention to provide adjustability for the trigger 16. When the trigger shoe is attached to the finger piece 19, adjusting means are provided which engage this trigger shoe and bear against the body portion of the firearm, that is, against any accessible portion of the firearm other than the trigger, for example the receiver assembly bottom or the forward portion of the trigger guard. Trigger shoes are conventionally employed for attachment to trigger finger piece to give the sensation of a lighter pull. The shoes are made in variout sizes and shapes so that the shoes may be connected to the finger piece while the finger piece fits snugly into a grooved portion 17 as best shown in FIG. 2.

Trigger slack and trigger travel are more pronounced in trigger mechanisms wherein the double action principle is utilized, as shown in FIG. 1. In a typical double action trigger mechanism such as the Mauser trigger mechanism shown in FIG. 1, where the trigger is pivoted on a trigger pin 38 to which sear 22 is connected, pulling the trigger 16 causes the trigger cam 20 to contact receiver 18 as the trigger slack is taken up. Further pull on the trigger with the cam bearing against receiver 18, forces trigger pin 38 and consequently sear 22, downwardly so that the sear lug 24 moves downward to release the cocking piece lug 26 whereby the spring biased cocking piece 34 is urged forward to force the striker assembly and firing pin 30 into the firing chamber (not shown) of the firearm to ignite a cartridge. The striker assembly travel and hence the amount of penetration of the firing pin 30 into the cartridge, is controlled by the engagement of the cocking piece lug 26 with the receiver stop 32. The trigger mechanism is cocked by retracting the cocking piece 34 so that the cocking piece lug 26 is positioned behind the sear lug 24. The sear is pivoted on sear pin 23 whereby the sear lug 24 on one end of the sear is forced upwardly or loaded by coil spring 36 on the other end of the sear. Thus the sear lug 24 is urged upward into engagement with the cocking piece lug.

Trigger slack is the movement that the trigger makes between its normal rest position, shown in phantom line, and the position shown in solid line where the trigger cam 20 first engages the receiver 18. Trigger travel is the distance the trigger moves between its initial engagement of the cam 20 with the receiver, and the position of the trigger when the sear lug 24 is forced downwardly until it is out of engagement with the cocking piece lug. “Backlash” is the distance the trigger finger piece 19 travels after releasing the cocking piece lug when the trigger either touches the trigger guard or the front portion of the sear engages the floor of the receiver.

In the embodiment of my present invention shown in FIG. 1, a modified trigger shoe 14 having a forwardly extending portion 49 is attached to the trigger finger piece 18 within the trigger guard as shown, in any convenient manner as with set screws 42. An adjusting screw 44 is positioned in the forwardly extending portion 40 of the trigger shoe so that the upper end of the adjusting screw 44 engages the bottom or lower surface 46 of the receiver assembly. When screw 44 is screwed through, rearward movement of the trigger is effected so that trigger slack and the trigger travel is reduced.

A second adjusting screw 48 may be inserted through the finger portion 15 of the trigger shoe to provide an adjustable means for reducing backlash, as the screw 48 is aligned so that as the trigger is pulled rearwardly, the end 49 of screw 48 will engage the trigger guard 12. The screws 44 and 48 may be locked with a set screw or have threads of the type which do not loosen easily, such as “progressive” threads or “tight” threads, both of which are well-known to those skilled in the art.

A modification of my present device shown in FIG. 3

3,208,884 ³ permits installation of a device embodying my present invention on a pistol or other firearm having a relatively small trigger guard. In this device the trigger slack and travel adjustment screw 45 bears against the trigger guard 13 as shown rather than against the magazine floor. The 5 trigger shoe 54 is modified as shown to fit the trigger guard 13.

Another modification of my present device is shown in FIG. 4 wherein a rod member 50 is slidably engaged within the trigger shoe and the forward end of the rod mem- 10 ber 50 is adapted to engage either the receiver assembly bottom 46 or the forward portion 56 of the trigger guard. The position of the rod may be secured within the trigger shoe with a set screw 52 to lock the rod in the position desired where trigger slack and travel are removed. 15

Although my present invention has been described with respect to several specific embodiments thereof with a certain degree of particularity, it is to be understood that my invention is of the full scope of the appended claims and should not be limited to the details set forth above. 20