US2780965A - Fire control mechanism - Google Patents

Description

Feb. l2, 1957 w. R, KuNz l FIRE CONTROL MECHANISM s sheetsQsheet 1 Filed Oct. 14, 1954 Y l IN VEN TOR. \/\/l1111:lm f H KUNZ W///////// \\\\\\V\\\\\\\\\\\ W m. X

Arroz/wif? Feb. 12, 1957 w. R. KuNz .2,780,955

' FIRE CONTROLVMECHANISM I Filed Oct..4 14, 1954 ,3 Sheets-Sheet 2 Vll/ s\\\\\\\\\\\\\\\\\\\\\\\ INVENTOR. A

William H KUNZ HTTONE YS Feb. 12, 1957 w. R. KUNZ FIRE CONTROL. MECHANISM v 5 Sheets-Sheet 3 Filed 0G11. 14, 1954 r AWignl'mm Y HTTO/VEY z,7s0,96s FIRE CONTROL MECHANISM William R. Kunz, Springfield, Mass., assignor to the United States of America as represented by the Secretary of the Army Application ctober 14, 1954, Serial No. 462,405

6 Claims. (Cl. 89--154) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Goverment for governmental purposes Without the payment of any royalty thereon.

This invention relates to trigger mechanisms for semiautomatic firearms and more particularly to trigger mechanisms of in-line operation.

lt is an object of this invention to provide a trigger mechanism wherein the Sear is released by a short trigger pull.

It is another object of this invention to provide a trigger mechanism for semi-automatic firearms wherein the hammer is positively reengaged by the sear when recoiled to cock position.

It is a further object of this invention to provide a trigger mechanism for semi-automatic irearms which is rugged in construction and positive in operation.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which: I

Fig. 1 is a longitudinal cross-sectional view of the trigger mechanism of this invention showing the ham mer engaged in cock position by the sear;

Fig. 2 is a view similar to Fig. l but showing the sear retracted to release the hammer; v

Fig. 3 is a view similar` to Figs. l and 2 but showing the actuator block released from the sea-r carrier by the hammer during movement to re position;

States Patent Y 2 20. Such safety is provided with a radially projecting lug portion 36 which is rotatable into engagement with the forward vertical wall 38 of cutaway portion 34 when mounting pin 18 is rotated by a handle 37 attached thereto to safe position.

A compressible coil spring 39 bears against the rear end of actuator block 24 to urge such actuator block against sear carrier 24. The forward movement of sear carrier 26 is stopped by a transverse pin 40 mounted through channel member 14 and receiver 12. Actuator block 24 is arranged to be pulled rearwardly by a lanyard v42 attached thereto, such rearward movement being controlled by safety which, when rotated to safe position, lug` 36 thereon engages wall 38 to hold the actuatorV block immovable against ,sear carrier 26 and permits limited reciprocal movement of the sear carrier and actuator block when such lug is rotated out of engagement with such wall when the safety is moved to olf position. Y

view showing the sear partly pivoted by theV hammer' to unlatch position 'during movement'ther'eof to cockposition; v p t Fig. 5 is a fragmentary longitudinal cross-sectional view lshowing the safety device in safe position; and

AFig. 6 is a perspective exploded View of the trigger mechanism of this invention.

Shown in the figures is a rearm receiver 12 and a substantially `U-shaped channel member 14 removably mounted therein by means of a retaining pin 16 and a mounting pin 18 which also serves as a bearing for a safety 20 linked thereto for rotational movement between a safe and an 0E position. A hammer 22 is mountedpforwardly of channel member 14 'in receiver `12 for pivotalmovement between a rearward cock position and an upward re position and is arranged to be vpivoted to cock position by recoil of the firearm bolt (not shown).V A springl biases hammer 22 from cock to lire position. Y

Mounted for slidable movement in channel member 14 is an actuator block 24 and a sear carrier 26 for wa-rdly thereof. Suchsear carrier and actuator block are, provided with longitudinal tongue portions, 28V and 30 respectively, which ,protrude from the sides there of for slidable engagement with a pair of longitudinal grooves 32 which extend along the insides of-th'e verti-` calwalls of channel member 14. The upper rear portion of actuator block 24 is cutaway to `form a right angle cross-section,"as noted at 34, for receiving safety Provided in the front end of actuator block 24 is a vertical channel 44 in which a connector member 48 is mounted for pivotal movement on a transverse pin 46. Such connector member includes a forwardly extending hook portion 49 which is receivable by a transverse groove 50 in the'top side of sear carrier 26 for releasably connecting such sear carrier to the actuator block for unitary movement. Also, an upwardly extending arm portion 52 provided with an upwardly and forwardly inclining cam `surface 54 and an inclined surface 56 which extends upwardly and rearwardly therefrom. Such hook and arm portions are located above pin 46. A depending lug portion 58 extends from con nector member 48 below pin 46. When hook 49 is disengaged from groove 50 and scar carrier 26 and actuator block 24 are separated, such hook portion is slidably engaged with the top of the sear carrier rearward of such groove.

Extending upwardly from the front portion of sear carrier 26 is a pair of laterally spaced ears 60 which are drilled to receive a transverse shaft 62 upon which there is mounted for pivotal movement a sear 64. Such sear is provided with a forwardly extending, downwardly facing latch portion 66 from the front end of which a camV surface 68 extends upwardly and rearwardly. An overhanging portion V69 projects rearwardly from sear 64 to be engageable with the top side of sear carrier 26 when latch portion 66 is parallel with the longitudinal axis of channel member 14 and whereby such latch portion is permitted to be pivoted away from such longitudinal position only in a downward' direction.

Extending longitudinally through sear carrier 26 is a bore 70 and slidably vmounted therein is a plunger 72 which projects therefrom toengage lug portion 58 of connector 48. A compressible coil spring 74 is mounted in'bore 70 forwardly of plunger 72V and is arranged to bear resiliently against such plunger and a lug portion 76 depending from sear 64 below shaft 62.1Whereby,

connector 48 is pivoted to resiliently press hook portion' l carrier 26 for cooperable engagement with arm .portion 52"of connector 48, as hereinafter described, whensear` l carrier 26 is in forward positiongblut` to pass'V freely thereby when such -sear carrier is in the rearward'posi- Projecting from the end of leg portion tlil'isfaV shelf 84 the top of which matinglyengages latch por tion.

tion 66 of sear 64 when hammer 22 is in cock position and sear carrier 26 istengaged with pin 40 andis disengaged therefrom when such sear carrier and actuator binds 2,4, are pulled rearwatdly by Lanyard 42, te their warmest positions- Operation To fire the firearm in which the. trigger Ymechanisrri of this invention is incorporated, the firearm is charged by retracting the bolt thereof (not shown), whereby hammer 2K2 is p ivotcd to cockl position, winding spring l5. When hammer 22v is in cock position, shelf 8d thereon is in full engagement with latch portion d6 of scar 64 with the engagement of overhangingporticn 69; cf. scar 64.- against the top of 'Sear carrier 26 preventing the` pivoting of/such sear to unlatch such hammer, and such' latch portion. is pressed forwardly into engegement with suchvshelf through the biasot Spring 9againstfactgatcr block 24..

Lanyard 42 is. then. pulled t0 draw actuator block 24 attached thereto rearwardly, andas such actuatorV block is joined to Scar Carrier 2,16 by means ot ctmnccttnrA 4& Such se'ar carrier is drawn'rearwardly also, disengaging latch portion dofscar dfrom shelf S4A of hammer 22, When disengageciy from seal- 64, hammer -22 is biased to fire Position by the Woundsnring 15- During theA initial movement of hammer 2,2?, arm portion 82 thereon engages cam surfacev S4y to-cam'mingly pivot connector 48` so that` hook portion 49i thereof is disengaged from groove 50ct scar carrier 26. Thus,v Sear carrier 2 6v is disengaged from actuator block 24V and free to be returned to normal position against pin 4,6, ready toL relatch hammer 22 by the bias of spring 74. On the ensuing recoil of the iirearm boltl (notrshown), fo1lowing the firing of therearm, hammer 22 is pivoted thereby, as already explained, to cock positionwith shelt" 84 there i eugagingagtsurfacc 68 cftsear 64 to. tiltlatch portion tithere'of downward against thebias of springk 74,permitting such shelfy to pass b y such latch portion for reengagement therewith.

If by chance the operator should release lanyard 42,y permitting actuator blockI 24 to be, returned to forward position against Sear carrier 2,6 before hammer-22 is pivoted'to cock position, arm 5`2 ,will be moved out, of the Way. of the passing armlportion 82 ofV such hammerY by. the camming engagement thereof with inclinedk surface 56. When lanyard 42, isV released, permitting actuator block 2,4y to bebiased forwardly by, spring 39, hook por.- tion 4,9; of connector 48; ywhichhas been slidablyengaged with the, top side of scar carrier ZslidSQIWardIyA/to berceivedby groove 50,2111@,therehyfertgagsS-.Sear carrier 2,6110 actuatorY block 24 ready to be pulledfrearwardly by lanyard 42 yto ire anotherround.

From the foregoing it isl clearlyfapp'arentthat there is herein provided a novel, trigger mechanismy of. in -line operaticrxnA which has` a, short trigger pull, is of,l positive neraticnandis. Simple and nlgged in [construction Although a partisularembodimcnt0f the inventive-.has

been described inl detailv here it isvevident thatmanyvariations may be' devised Within.,Y the. Spirit.. and` scope:

grooves therealong, atsear deviceforreleasably holding said hammerin said cockposition mounted for slidable movement along said groove, sear actuating, means mountedfor slidable movementy alongf said groove rearwardly of said sear device, connectormeansffor releasf, ably engaging said seardevice toj said scarLA actua-ting means, i ald an arm m1; Saidhammerfcamminglyvncoper- Y able said-,connectormeans `for disengaging said 'sean device from said scar actuator means during movement ol" said hammer from said cock position to said fire position.

2. In a firearm having a receiver, a trigger mechanism including a hammer pivotally mounted in the receiver for reciprocation between a cock position and a fire position, a channel member fixedly mounted in the receiver real'- wardly of said hammer and provided with longitudinal groovestherealong, a Sear device mounted for sliding movement along said grooves between a latch position wherein said hammer is releasably held in said cock position and an unlatch position, means for biasing said scar device to said latch position, sear'actuator means mounted in said channel member rearwardly of said scar device for sliding movement along said' grooves, resilient means for biasing said scar actuator means towards said sear device, connector means for releasably engaging said Sear actuator means to saidk sear device whereby said scar device is movable by said Sear actuator mea-ns to said unlatch position, and` anarm on said hammer cammingly cooperable with, saidV connector means during movement of said hammer from said cock position to said tire position for disconnecting said Sear device from said scar actuator means whereby-said scar device is returnableA to said latch position by said means for unlatching said hammer when actuated to said cock position.

3. In a` firearm having a receiver, a trigger mechanism including a hammer pivotally mounted in the receiver forl reciprocation betweenA a cock position and a lire position, a sear device mounted in the receiver for reciprocal longitudinal movement between a latch position wherein said hammer is releasably heid by said scar device in said cock positionandanA unlatchv position, sear actuator means mounted for reciprocal longitudinal movement in the receiver, a spring for biasing said sear actuator means toward saidsear device, means for moving said' scar actuator against the bias of said spring, aconncctorv mounted toJv said scar actuator means for pivotal movement on a pin transversely therethrough, said connector being provided with an armhaving a camlsurface and a projecting hook portionV disposed abovcsaid pin and a lug portion depending below said pin, `said hook portion being engage,- ablewitlia groove in said seardevice for releasably connecting said scar device to said scar actuator means, a

coil springmountedV between saidsear device and said lug 'for simultaneously biasing-said-sear device to said latch position'andisaid hookportion into engagement with said grooye, andanl armfportionprojecting from said hammerk for engagement with said cam" surface during actuation. from said cock position to said fire-position for pivoting said connector to discngagesaid hook frornsaidv groove whereby saidsear device is disconnected-from, said scar actuator means for the return of s aid sear device tosaid latch positionby saidcoilspring to-relatch said hammer when actuated tosaid cock position.

4. In a firearm4 having a, receiver, a trigger mecha-- nism, including a hammer pivotally mounted in there ceiver forV reciprocationl between av cock position andA a fire position, a scar; carrier mounted in the receiver` for reciprocal )longitudinal movement between a forward' positionand a rearward position, a. scar havingl alatchV portion mounted inA said carrierV for pivotal movementv between a'latch-position wherein said latch. portion is disposedparallel to theflongitudinal axis of said scar -carrier and an unlatch'position wherein saidglatchportionisinclineddownwardly, an overhanging portion eX- means for moving said sear actuator against the bias of said spring, connector means for releasably engaging said sear carrier to saidrsear actuator, an arm on said hammer cammingly cooperable with said connector means for releasing said sear carrier from said sear actuator, and spring means for simultaneously biasing said carrier to said forward position when released from said sear actuator and said Sear to said latch position.

5. In a rearm having a receiver, a trigger mecha nism including a hammer having a leg` portion and an arm portion at right angles thereto, said hammer being pivotally mounted in the receiver for reciprocation between a cock position wherein said leg portion extends downwardly and said arm portion extends rearwardly therefrom and an upward fire position, a shelf portion extending from said leg portion toward said arm portion parallel with the longitudinal axis of the receiver when said hammer is in said cock position, a Sear carrier mounted in the receiver for longitudinal movement be tween a forward position and a rearward position, a sear having a latch portion mounted to said sear carrier for pivotal movement between a latch position wherein said latch portion is engageable with said shelf portion when said hammer is in said cock position and said carrier is in said forward position and a downward unlatch position wherein said shelf portion is passable thereby for engagement with said latch portion, an actuator member mounted in said receiver rearwardly of said carrier for reciprocal longitudinal movement, said actuator being normally biased rby a spring toward said carrier, means for moving said actuator against the bias of said spring, a connector rotatably mounted to said actuator for releasable engagement with said carrier whereby said carrier is movable to said rearward position by said ac tuator, said connector being provided with a cam portion engageable by said arm portion during movement of said hammer from said cock position to said fire posi- Vtion for pivoting saidv connector to disengage said carrier from said actuator, and spring means cooperating with said sear and said connector for simultaneously biasing said sear to said latch position, said carrier to said forward position and said connector into engagement with said carrier.

6. In a firearm having a receiver, a trigger mechanism including a hammer provided with an arm portion and a leg portion at right angles thereto having a shelf projecting therefrom toward said arm portion, said hammer being pivotally mounted in said receiver for reciprocation between a cock position wherein said leg portion extends downwardlyand said arm portion rearwardly therefrom and an upward lire position, a scar carrier mounted in said receiver rearwardly of said hammer for reciprocal longitudinal movement between a forward position and a rearward position, a sear provided with a latch portion mounted for pivotal movement between a latch position wherein said latch portion is engageable with said shelf portion when said hammer is in said cock position and said carrier is in said forward position and a downward position wherein said shelf portion is passable thereby during movement of said hammer to said cock position for latching with said latch portion, an overhanging portion extending from said sear for en- K gagement with said carrier to prevent the pivoting of said latch portion upwardly away from said latch position, an actuator mounted in said receiver rearwardly of said carrier for reciprocal longitudinal movement, spring means for biasing said actuator forwardly toward said carrier, actuating means for pulling said actuator against the bias of said spring means, a connector mounted for pivotal movement on a transverse pin through said actuator, said connector being provided with an arm and a hook disposed above said pin and a lug portion projecting below said pin, said hook being receivable by a groove in said carrier for releasably engaging said actuator thereto, said arm being provided with a cam surface engageable by said arm portion of said hammer during movement thereof from said cock position to said re position for pivoting said connector to disengage said hook from said groove and an inclined surface extending from said cam surface for engagement by said arm portion of said hammer during movement thereof from said re position to said cock position for cammingly moving said arm portion out of the way thereof, and a spring mounted between said lug and a depending portion of said sear for simultaneously biasing said carrier to said forward position, said sear to said latch position and said hook into engagement with said carrier.

References Cited in the le of this patent UNITED STATES PATENTS 580,923 Browning Apr. 20, 1897 821,922 Burgess May 29, 1906 885,436 Clement Apr. 28, 1908

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