US1981855A

US1981855A - Sear mechanism for guns

Info

Publication number: US1981855A
Application number: US627244A
Authority: US
Inventors: Richard C Coupland
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-08-02
Filing date: 1932-08-02
Publication date: 1934-11-27
Anticipated expiration: 1951-11-27

Description

Nov. 27, 1934.

R. C. COUPLAND SEAR MECHANISM FOR GUNS Filed Aug. 2, 1932 Hal 2 Sheets-Sheet l 36 Inventnr- Richard fijuupland Attnrney Nov, 27, 1934. C UPLAND 1,981,855

SEAR MECHANISM FOR GUNS Filed Aug. 2, 1932 2 Sheets-Sheet 2 l) WNW! ,9

Inventor" Richard fijuupland Attur'nE-y Patented Nov. 27, 1934 I g 1,981,855 VSEAVRMZECHANISM FOR GUNS y i Richard 0. Coupland, United Norfolk, Va.

States Army,

1 Application August 2, 1932, SerialNo. 627,244 10 Claims. (01. 89 27) (Granted under the act of March 3,1883} as V amended April so, 1928; 370 o. G. 757) '5 This invention relates to a sear mechanism for guns. I

In mounting fixed machine guns on aircraft, it is customary to operate the gun by means of a trigger motor synchronized with the propeller of the aircraft and adapted to be placed on either side of the gun. When the gun is mounted in afiexible mannera hand trigger is employed to control the firing mechanism. Where one gun is to be adaptable for all of the methods of operation it is necessary that the slide forreleasing the sear be so arranged that it can be actuated from three. different directions.

The principal object of this invention is to provide a sear mechanism that will meetthe foregoing requirements with a minimum adjustment of parts and that will be operable upon the application of asslight force. A further object of the invention isxto so arrange the sear. mechanism that the firing pin will be able to pass through it and .strike the bufierplateof the. gun. V I

With the foregoing and other objects inlview, the inventionresides in the novel arrangement and combination of parts and in the details of .30 construction hereinafter described and claimed,

it beingunderstood that changesin the precise embodiment. of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the inven- 35 tion. 7 V M A practical embodiment of the invention is illustrated in the accompanying drawings, wherein: r

Fig. 1 isa longitudinal sectional view through the receiver of a machine gun showing thefiring pin held in cockedp'os'ition by the sear. I

Fig. 2 is an enlarged longitudinal sectional view of the rear en d of the belt of Fig. 1.

Fig. 3 is. a view similar to Fig. 2 showing the relative position of the parts whenthe firing pin is in fired position. 2 Figs. 4 and 5 are views in rearelevation of the bolt corresponding respectively to Figs. 2 and 3. Fig. 6 is a plan view of Fig. 4. 2 I

Figs. '7 and 8 are detail views respectively in rear and side elevation of the sear.

r Fig. -9..isa plan view of the sear.

Figs. and i1 are detail. views respectively implan .and rear-elevation of the transverse slide.

Fig. 12' shows views in rear andside elevationof the vertically movable'slide.

Referring to the drawings by numerals of reference thereis shown the receiver frame 5 of a machine gun within which a bolt 6 is reciprocally mounted. Within the bolt is a longituclinally disposed firing pin 7 normally urged in a forward direction by means of a spring 8 housed in the firing pin and seated on a vertical pin 9 passing through the bolt. The firing pin is cooked in a well known manner by the lever 10 when the bolt moves in recoil.

The firing pin is held in cocked position by means of a sear 11 which is mounted for vertical sliding movement in a slot 12 in the rear end of the bolt and is formed with ribs 13 on its opposite sides which fit in grooves 14 in the side walls of the slot. The sear includes a transversely disposed lug l5 movable into and out of a transversely disposed groove 16 formed in the upper surface of the firing pin adjacent its rear end. The rear face 17 of the lug is inclined to coact with a correspondingly inclined face 18 defining the rear wall of the groove 16in the firing On the front end of the sear is a bent finger 19 the extremity of which is disposed in the groove 16' of the firing pin when the latter is in the cocked position as shown'in Fig. 2. In Fig. 3 where the firing pin is in the firing position the extremity of the finger rests on top of the rear end of the firing pin and serves to hold the sear in the elevated position. 7

A pair of lugs 2020 on the sides of the sear, one below each of the ribs 13 and spaced therefrom are provided for a purpose that will appear later. A plunger 21 mounted in the upper por tion of the sear and urged outwardly by a spring 22 is seated against a. bar 23 rigidly carried by the pin 9. The plunger opposes elevation of the sear, and normally tends to depress it into engagement with the firing pin. The lower por tion of the seat is. formed with an opening 24 to permit the rear end of the firing pin '7 to strike the b ufier plate 25 when the bolt has been arrested by the buffer plate,

The rear end of the bolt is formed with a transversely disposed slot 26 having grooves 2727 at its inner end. A slide 28, (Figs. 10 and 11) insertable in the grooves .27 from either side of the bolt is disposed in front of the sear. A

more or less centrally located aperture 29 in the slide permits the rear portions of the firing pin to'mov'e through "the slide. v V

A pair of spaced lugs -30 are provided on the rear face of the slide at one side of the aperture 29 and have inclined faces 3131. These lugs lie in the vertical transverse plane containing the lugs 20-20 on the sear.

On the other side of they aperture 29 is a The plunger spring 34 is disposed in the housing 32 and a pin 35 limits extrusion of the plunger under the influence of the spring. The slide is symmetrical about a longitudinal axis so that it may be reversed and; inserted from either side of the bolt, depending upon the location of a synchronized trigger motor.

The lower portion of the vertical slot. 12 in the bolt includes grooves 36- 36 for receiving a vertically movable slide 37. This slide is inserted from above and includes an car 38 on each side for engaging the fioor of the transverse slot 26 and limiting downward movement of the slide. The upper corners of the slide are inclined as at 39 complementary to the inclined faces 31 of the lugs 30. This slide is adapted to be elevated by the hand trigger mechanism of the machine gun.

In Figs; 2 and 4,the, lug 15 on the sear is engaged in the groove 16 of the firing pin which is in cocked position and-the sear is prevented from being raised by virtue of the engagement of one of its lugs 20 under the lip of the uppermost lug 30 on the slide 28. The slide 28 is maintained in the locking position by means of the spring-pressed plunger 33. When the slide is moved laterally (to the left in Fig. 5) the lug.

30 is no longer in the path of movement of the lug 20 on the sear.

As soon as the sear is released the firing pin spring 8 moves the firing pin '7 forward, the transverse lug 15 on the sear being cammed out of the groove 16 in the firing pin by virtue of the coaction of the-

inclined surfaces

17 and 18. Upon elevation of the sear the bent finger 19 is moved out of the groove 16 and the firing pin in moving forward comes to rest with its rear end directly under the finger 19 (Fig. 3). As a consequence the sear is held inthe raised position against the action of the plunger 21 which tends to depress it, and it cannot be lowered into the path of the firing pin. In this position of the parts the lug 20 on the elevated sear isin the path of movement of the lug 30 on the slide 28.

As the bolt moves in recoil the cooking lever 10 retracts the firing pin against the tension of the firing pin spring. As soon as the finger 19 is clear of the rear end of the firing pin the sear is depressed by its spring into the groove 16. This depression of the sear moves thelug 20 be-' low the lug 30 on the slide 28 and the slide under the influence of its spring immediately moves laterally of the bolt and positions the lug 30 above the lug 20 thereby locking the sear and firing pin in cocked position.

The slide 28 is actuated directly from the side of the bolt or it. is actuated indirectly through the vertical slide 37.

I claim:

1. In a gun, a reciprocal breech bolt, a firing pin having a groove adjacent its rear end and movable relative to the bolt, a cooking lever for the firing pin, a vertically movable sear carried by thebolt and adapted to be elevated by the firing pin on forward movement thereof, a spring the scar and having an aperture through which the firing pin is movable, a pair of spaced lugs on said slide in the plane of the lugs on the sear, one of the lugs on the sear. engageable under one of the logs on the slide when the sear is depressed, a plunger on the slide engageable with the sear and normally holding the slide in searin the bolt operable to move the transverse slide out of sear-locking position.

2. In a gun, a reciprocal breech bolt, a firing pin having a groove adjacent its rear end and movable relative to the bolt, a cocking lever for the firing pin, a vertically movable sear carried by the bolt and adapted to be elevated by the firing pin on forward movement thereof, a spring normally tending to depress the sear into engagement with the firing pin to hold the same in cocked position, means on the sear disposed in the groove of the firing pin when cooked and engageable with the firing pin when fired whereby the sear is held in the elevated position, 2, lug on each side of the sear, a transversely movable slide reversibly mounted in the bolt in front of the searv and having an aperture through which the firing pin is movable, a pair of spaced lugs on said slide in the plane of the lugs on the sear, one of the lugs on the sear engageable under one of the lugs on the slide when the sear is depressed, and a plunger on the slide engageable with the sear and. normally holding the slide in sear-locking position.

3. In a gun, a reciprocal breech bolt, 2. firing pin having a groove adjacent its rear end and movable relative to the bolt, a cooking lever for the firing pin, a vertically movable sear carried by the bolt and adapted to be elevated by the firing pin on forward movement thereof, a spring normally tending to depress the sear into engagement with the firing pin to'hold the same in cocked position, means on the sear disposed in the groove of the firing pin when cocked and engageable with the firing pin when fired whereby the sear is held in the elevated position, a lug on the sear, a transversely movable slide mounted in the bolt in front of the sear and having an aperture through which the firing pin is movable, a lug on said slide in the planeof the lug on the sear, the lugon the sear engageable under the lug on the slide when the sear is depressed, and a plunger on the slide engageable with the scar. and normally holding the slide in sear-locking position. v

4. In a gun, a reciprocal breech bolt, a firing pin movable relative to the bolt, means for cooking the firing pin, a vertically movable sear carried by the bolt and adapted to be elevated by the firing pin on forward movement thereof, a spring normally tending to depress the sear into engagement with the firing pin, means on the sear engageable by the firing pin whereby the sear is held in the elevated position, a transversely movable slide reversibly mounted in the bolt in front of the scar and having an aperture through which the firing pin is movable, and means seated on the sear for normally moving the slide into position to engage the sear.

1.5. In a gun,.a reciprocal breech bolt, a firing .moving the slide into position to engage the sear. i i

6. In a gun, a reciprocal breech bolt, a firing pin movable relative to thebolt, means for cocking the firing pin, a vertically movable sear carried by the bolt andadapted to be elevated by the firing pin on forward movement thereof, a spring normally tending to depress the sear into engagement with the firing pin, means on the sear engageable by the firing pin whereby the sear is held in the elevated positioma transversely movable slide mounted inthe bolt in front of the sear and having an aperture through which the firing pin is movable, and means for normally moving the slide into position to engage thesear.

'7. In a gun, a reciprocal breech bolt, a firing pin movable relative to the bolt, means for cooking the firing pin, a vertically movable sear carried by the bolt and adapted to be elevated by the firing pin on forward movement thereof, means for normally depressing the sear into engagement with the firing pin, a finger on the sear engageable by the firing pin when the firing pin is in forward position whereby the sear is held in the elevated position, and a slide working between the sear and the finger for locking the sear.

8. In a gun, a reciprocal breech bolt, a firing pin movable relative to the bolt, means for cooking the firing pin, a vertically movable sear carried by the bolt and adapted to be elevated by the firing pin on forward movement thereof, means normally tending to depress the sear into engagement with the firing pin, a lug on each side of the sear, a transversely movable slide reversibly mounted in the bolt, a pair of spaced lugs on the slide, one of the lugs on the sear engageable un-, der ,one of the lugs on the slide when the sear is depressed, a plunger on the slide engageable with the sear and normally holding the slide in sear-locking position, and a vertically movable slide in the bolt engageable with one of the lugs on the slide to move the slide out of sear-locking position.

9. In a gun, a reciprocal breech bolt, a firing pin movable relative tothe bolt, means for cocking the firing pin, a vertically movable sear carried by the bolt andadapted to be elevated by the firing pin on forward movement thereof, means normally tending to depress the sear into engagement with the firing pin, a lug on each side of the sear, a transversely movable slide reversibly mounted in the bolt, a pair of spaced lugs on the slide, one of the lugs on the sear engageable under one of the lugs on the slide when the sear is depressed, and a plunger on the slide engageable with the sear and normally holding the slide in sear-locking position.

10. In a gun, a reciprocal bolt, a firing pin movable relative to the bolt, means for cooking the firing pin, a sear engageable with the firing pin to hold it in cocked position, a sear-lock reversibly mounted in the bolt whereby it may be operated in reversed directions to release the