US2715355A

US2715355A - Fire control mechanism

Info

Publication number: US2715355A
Application number: US606699A
Authority: US
Inventors: John C Garand
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-07-23
Filing date: 1945-07-23
Publication date: 1955-08-16
Anticipated expiration: 1972-08-16

Description

Aug. 16, 1955 J. c. GARAND FIRE CONTROL MECHANISM 4 Sheets-Shed l Filed July 25, 1945 Aug. 16, 1955 J. c. GARAND FIRE CONTROL MECHANISM 4 Sheets-Sheet 2 Filed July 25, 1945 Jul-1N [LE/ARIANE),

afmf/MMM Aug 16, 1955 J. c. GARAND 2,715,355

FIRE CONTROL MECHANISM Filed July 23, 1945 4 Sheets-Sheet 3 Jill-IN E. EAEAND,

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@M a fmdmw Aug. 16, 1955 J. c. GARAND FIRE CONTROL MECHANISM 4 Sheets-Sheet 4 Filed July 25, 1945 Jul-LTL E.. Enrnnd Unite The invention described herein may be manufactured and used by or for the Goverment for governmental purposes without the payment to me of any royalty there- This invention relates to a selective fire control mechanism for automatic firearms having reciprocating bolts.

An object of this invention is to provide an improved tire control mechanism for a rearm selectively permitting both semi-automatic and full automatic tire control.

A particular object of this invention is to provide a re control mechanism permitting both semi-automatic and full automatic tiring for a firearm of the type disclosed in my U. S. Patent No. 2,377,338.

Still another object of this invention is to provide a re control mechanism for an automatic lirearm of the reciprocating bolt type wherein full automatic ring is initiated from an open or retracted bolt position while semi-automatic tiring is initiated from a locked bolt position.

The speciiic 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:

Fig. l is a fragmentary longitudinal side view of an automatic firearm with certain parts thereof broken away to show the lire control mechanism assembled therein. Such mechanism is shown set for semi-automatic re after the first round has been red and the trigger is still pulled rearwardly.

Fig. 2 is a reduced size, side elevational view of an automatic irearm embodying this invention showing the actuating link in assembled relation.

Fig. 3 is a perspective view showing the sear release member assembled to the actuating link.

Fig. 4 is an exploded view of the eccentric utilized to change the position of the actuating link and the knob utilized to rotate such eccentric in change from semi-automatic to automatic iire.

Fig. 5 is a fragmentary detail view showing the lug on the underside of the receiver utilized to mount the sear release member.

Fig. 6 is a partial sectional View taken along the plane 6 6 of Fig. 1.

Fig. 7 is a partial sectional view taken along the plane 7 7 of Figure 1 and showing the L-shaped lug on the underside of the forward end of the actuating link.

Fig. S is a fragmentary perspective view showing details of the slot under the guide rib of the receiver, as viewed from line 8 8 of Figure l, utilized to secure the forward end of the actuating link.

Fig. 9 is a partial sectional view taken along the plane 9 9 of Fig. l and showing the mounting of the sear release member and the eccentric.

Fig. 10 is a partial sectional view taken along the plane 10-10 of Fig. 1.

Fig. 11 is a partial sectional view taken along the plane 11 11 of Fig. l and showing the bolt sear notches on the bottom side of the bolt.

States arent Fig. l2 is a partial sectional view taken along the plane 12-12 of Fig. l and showing the spring connection between the actuating link and the sear release member.

Figure 13 discloses the relationship of certain parts of the fire control mechanism of Figure l when the rearm is set for automatic fire, the trigger being shown pulled back, the hammer forward and the bolt in battery position.

Figure 14 is a perspective view disclosing details of the secondary sear and the trigger and the manner of mounting of the former upon the latter.

The invention to be described in more detail later essentially comprises a sear release member pivotally mounted on the receiver or" the iirearm and connected to the operating rod of such firearm by a link to control the release of a hammer sear. The sear release is pivotally mounted on an eccentric so that the link can be readily engaged or disengaged from the operating rod by rotation of such eccentric. Normal semi-automatic fire of the rearm is obtained when the link is disengaged from the operating rod of the iirearm. Full automatic ire is obtained when the eccentric is turned in such position that the operating rod, moving into its battery position, will contact the forward end of the link to rotate the sear release member, thereby automatically releasing the sear to produce full automatic lire. In full automatic fire the bolt is held in the open position by an auxiliary Sear prior to release of the trigger so that before discharge of the lirst round of each burst, the bolt has to travel forwardly and lock before the hammer is released to strike the ring pin.

Referring to the drawings there is shown in Fig. 1 in assembled relation, a firearm embodying this invention. Such iirearm comprises mainly a receiver 1, a reciprocating bolt 2, an operating rod 3 and a barrel 4. Details of the construction and operation of these main elements of the rearm are substantially similar to that disclosed in my prior U. S. Patent No. 2,377,338, and need not be further described here.

A lug 5 is integrally formed or brazed on the underside of receiver 1 as shown in Figs. l and 5. Lug 5 projects downwardly and is provided with a secondary depending lug 6. The rear surface 7 of lug 6 acts as a stop for a sear release 15 to be described. A transverse hole 8 is provided in lug 5 in which is inserted a selector 9. Selector 9 comprises a pin 10, a knob 21, a spring 23 and a tranverse pin 24. The integral head 11 of pin 10 is rectangular in configuration to obtain two positions of adjustment of selector 9 as Will be presently described. Pin 10 has an enlarged cylindrical portion 12 adjacent head 11. The center portion 13 of pin 10 is also cylindrical but is eccentrically formed with respect to portion 12 and such portion lies within transverse hole 8 in lug 5. The small cylindrical end portion 75 is concentric with portion 12 and lies within transverse hole S1 of a sear release 15. A transverse hole 74 is provided near the extreme end of portion for a purpose to be mentioned later.

Sear release 15 is a generally rectangular, bifurcated member and is provided with an integral downwardly projecting lug 14 which engages the stop lug 6 in a manner to be later described. Sear release 15 is bifurcated to permit pivotal mounting of such scar release in surrounding relation on lug 5. Sear release member 15 is also provided with an upwardly projecting arm 16 and on the upper end of such arm there is provided an integral, transversely projecting stud 17. A rearwardly facing hole 26 is provided in arm 16 between the stud 17 and transverse hole 81, to receive the end of a spring 27 for a purpose to be later described. An integral lug 25 (Fig. 9) is provided on the end of stud 17 disposed downwardly at an angle of approximately 45. Lug 25 3 is provided to lock a link 18 to the side of receiver 1 as will be later described. Y

A transverse hole 19 is provided in the left hand bifurcation of sear release as viewed in Fig. 9 thru which is inserted the cylindrical portion 12 of pin 10 while the smaller hole 81 in the right hand bifurcation receives cylindrical portion 75 of pin 10, thereby pivotally mounting the sear release to lug 5. The head 11 of pin 10 rests within a longitudinal slot 20 on the inside face of sear release 15 as shown in Fig. 9. Slot 20 is made sufficiently wide to accommodate head 11 only when the narrowest width of such head is so turned as to engage such slot. Sear release 15 is secured on lug 5 by knob 21 which is provided with an integral collar 22 substantially in the center thereof as shown in Fig. 4. Spring 23 is placed within collar 22 and such spring and knob are then placed over the end 75 of pin 10. A transverse pin 24 is then inserted thru a suitable hole in collar 22 and thru hole 74 in pin 10 to secure knob 21 thereto. Spring 23 rests against the bottom of collar 22 and against the outside surface of sear release 15. Thus when knob 21'is pushed inwardly, head 11 of pin 10 is forced out of slot 20 to permit selector 9 to be rotated to another position for a purpose to be described.

The actuating link 18 is provided with a substantially rectangular shaft-like body portion 28 having an integral lug 29 on the rear end thereof as shown in Fig. 3. Lug 29 has a transversely inclined, serrated manual-operating surface 30 for manually shifting the link 18 forwardly for a purpose to be described. A longitudinal hole 31 (Fig. l2) parallel to shaft 28 is provided in lug 29 to receive one end of spring 27 as will be later described. A slotted hole 32 (Fig. 3) is provided in body portion 28 just ahead of lug 29 to mount link 18 on stud 17 of sear release 15.

The forward end of link 18 is provided with an integral hook-like lug 33 on top of shaft portion 28 which engages a mating shoulder 34 (Figure 13) on a reciprocating member of the firearm, such as the operating rod 3. A vertically downwardly projecting lug 35 is also provided on the forward end of shaft 28 and a longitudinally extending slotted hole 36 is provided therein. The rear end of slotted hole 36 is enlarged vertically upwardly as shown at 37 (Fig. l) to permit link 18 to be dismounted from receiver 1 as will be presently described. On the innerside of the enlarged forward end of shaft 28 there is provided an upstanding longitudinal lug 38 (Figure 7). Lug 38 engages a groove 39 provided on the underside of the forward end of the guide rail 40 on receiver 1 as shown in Figs. 7 and 8. pin 41 (Fig. 7), which is utilized to support the rear end of an operating spring 42 and spring guide 42a on the forward end of receiver 1, projects outwardly from the side of receiver 1 suiciently to permit link 18 to be mounted thereon.

Link 18 is mounted on the right side of receiver 1 slightly below operating rod 3 as shown in Fig. 2. Such link is readily assembled to the rifle by holding link 18 with its forward end disposed downwardly at approximately from the horizontal axis of the firearm, and mounting the rear end of link 18 on stud 17 by means of slotted hole 32. One end of spring 27 is placed within hole 31 in link 18 while the other end is guided into hole 26 in sear release 15. The forward end of link 18 is then rotated upwardly and pulled forwardly, assisted by manual pressure upon the serrated surface 30, until the rear surface of slotted hole 32 strikes stud 17. The enlarged forward end of shaft 28 is then mounted on pin 41 by means of slotted hole 36. The vertically enlarged portion 37 of hole 36 is utilized for such mounting. The forward end of link 18 is then pushed upwardly until the bottom surface of slotted hole 36 strikes pin 41 whereupon lug 38 will lie in groove 39. Link 18 is then moved rearwardly by the bias of spring 27, thus the forward end of link 18 is slidably secured on pin 41 A transverse r and such end is retained on receiver 1 by engagement of lug 38 with groove 39.

The trigger guard grouputilized with this fire control mechanism is substantially similar to that utilized in Patent No. 2,377,338. Such trigger guard group comprises mainly a housing 43, a hammer 44, a trigger 45, a primary hammer sear 56, a secondary hammer sear 46, a safety 47, and a trigger guard 48. Hammer 44 is pivotally mounted at the forward end of housing 43 by a transverse pin 49. Trigger 45 is mounted on a transverse pin 51 between two integral upstanding lugs 50 near the rear of trigger housing 43 (Fig. 10). The sear 46 is mounted on a pin 56 carried by the trigger 45 above its axis of rotation, as shown in Figure 14, and a spring biased plunger 52 is within a housing 52 having apertured ears 51 pivotally mounted on pin 51 and is arranged to bias hammer 44 upwardly and forwardly in a manner fully described, all in my prior patent mentioned above. Safety 47 is likewise mounted as disclosed in my above-mentioned patent and functions in a similar manner as described therein.

In accordance with this invention, however, the rearwardly disposed arm of hammer 44 is bifurcated and within such bifurcation there is mounted a substantially triangularly shaped dog 53 which functions as a bolt sear (Figs. l, 6 and 10). Bolt sear 53 is pivotally mounted on hammer 44 by a transverse pin 54. Such pin passes through the forwardly disposed apex of bolt sear 53. The rearwardly facing edge 55 of bolt sear 53 is provided with a cam surface 69 which cooperates with the primary sear 56 of trigger 45, as will be later explained. A torsion spring 57 is looped about one end of transverse pin 54 and engages the rear surface of hammer 44 and the bottom surface of bolt sear 53. Such spring is provided to bias such bolt sear upwardly so that the top apex 82 of bolt sear 53 will be biased into engagement with one of a plurality of notches 58 (Fig. ll) provided on the underside of bolt 2 for a purpose to be later described. The upward rotational movement of bolt sear 53 is limited by a transverse pin 59 suitably secured to bolt sear 53 which engages the underside of hammer 44. Primary and

secondary sears

56 and 46 respectively are substantially the same construction as utilized in the foremen tioned patent, but the upper portion of secondary sear 46 is lengthened transversely, as shown in Figure 14, to provide a lateral extension 46 adapted to be engaged by sear release 15 as will be later described.

Receiver 1 has been modified somewhat from that disclosed in my prior U. S. Patent No. 2,377,338 to utilize a magazine 60 of the box type having a capacity of preferably not less than 20 rounds. Such magazine is shown assembled thereto in Fig. l. Magazine 60 is arranged to be held within the receiver 1 in a vertically disposed position by a magazine catch 61. The magazine catch 61 is a substantially cylindrical member and is provided with a forwardly projecting lug 62 which engages a notch 80 in the rear of magazine 6i). The catch 61 lies within a cylindrical hole 63 longitudinally disposed within housing 43 in the forward end thereof as shown in Fig. l. A helical spring 64 is placed within an axially aligned hole 65 in the bottom of hole 63. Spring 64 is provided to bias catch 61 forwardly into engagement with the notch 8G in magazine 60. The forward movement of catch 61 however is limited by a catch releasing member 66. Catch releasing member 66 comprises a lever arm 67 of substantially rectangular configuration which passes through a rectangular hole 68 vertically disposed in catch 61. The upper end of catch releasing member 66 is pivotally mounted on pin 49. The lower end of catch releasing member 66 projects rearwardly and downwardly to facilitate grasping in order that such member may be pulled rearwardly against the bias of spring 64 thus permitting magazine 60 to be released so that it may be readily removed from receiver 1 of the firearm. A follower 70 of magazine 60 rises into the path of bolt 2 after firing the last round thus holding the bolt in the open position so that the tirer can quickly determine that his iirearm requires reloading.

When using the fire control mechanism herein described with a firearm of the type similar to that described in the U. S. Patent No. 2,377,338, the semi-automatic operation of such firearm is not disturbed. That is to say, the hammer is normally held in the cocked position by primary sear 56 which engages a primary sear notch 72 provided on the underside of hammer 44. Release of hammer 44 is effected when trigger 45 is pulled rearwardly. After discharge of the cartridge, bolt 2 recoils and strikes hammer 44 thereby rotating hammer 44 in a counterclockwise direction as bolt 2 passes over such hammer. As trigger 45 is still held in the rearmost position, secondary sear 46 is pivoted forwardly into the path of hammer 44 whereupon such sear will engage a secondary sear notch 73 on the rear of hammer 44, thus holding hammer 44 in the cocked position. This is the condition illustrated in Fig. l. leased, secondary sear 46 slips off notch 73. However, upon release of trigger 45 the primary Sear 56 on such trigger simultaneously engages primary scar notch 72 on hammer 44 so when trigger 45 is fully released, the hammer is still held in the cocked position but by primary sear 55. Thus the trigger must again be pulled to fire the next shot and semi-automatic fire is obtained.

However, to obtain such semi-automatic fire, link 18 must be moved forwardly so that lug 33 thereof will be out of engagement with shoulder 34 of operating rod 3. This is the condition illustrated in Fig. l and for purposes of explanation, the sear release 15 may be considered to be a lever oscillatable about cylindrical portions 12-75 as a fulcrum, adjustable by eccentric portion 13, and rockable on the stud 17 as another fulcrum, with the spring 27 exerting its force on the sear release 15 between these fulcrums, always tending to turn sear release 15 on the stud 17 in a counterclockwise direction and yieldingly opposing clockwise movement, while simultaneously maintaining the stud 17 always against the for- Ward end of the slot 32 irrespective of the direction of rotation of the sear release. By pushing inwardly on knob 21, head portion 11 of pin 1G is raised out of engagement with slot 211 and knob 21 is then rotated 180. As the eccentric portion 13 of pin lil lies within hole 3 of lug 5, the axis of selector 9 is changed by such rotation. Thus, sear release 15 is moved bodily and forwardly as a result of which its projecting lug 14 first engages the stop plug 6. As rotation of the eccentric portion 13 is continued to completion, the Sear release 15 will then shift the stud 17 forwardly, and thereby the link 18 to move the lug 33 out of engagement with shoulder 34 on operating rod 3.

lt should be mentioned here that the bias of spring 27 is sufficient to maintain the forward wall of slotted hole 32 in link 18 in engagement with stud 17 at all times. When selector 9 is positioned for semi-automatic fire, bolt sear 53 is held out of engagement with either of the notches 58 on the underside 2 of bolt 2 by the engagement of cam 69 on the edge 55 of bolt sear 53 with forward face of primary sear 56. Bolt sear 53 cannot engage the notches 58 on bolt 2 in semi-automatic iire because the trigger has to be pulled and released for each shot. ln so doing such bolt sear is held out of engagement when the trigger is pulled and due to the high cyclic rate of such automatic firearms, before the trigger can be released, the bolt has returned to the breeched position where it remains until discharge of the next round. Thus bolt sear 53 is not effective during semi-automatic operation.

The improved fire control mechanism herein described is readily changed to automatic fire by rotating knob 21 180 from the semi-automatic position, as shown in Figure l, so that lug 33 of link 18 will be moved rearwardly into engagement with shoulder 34 of operating When trigger 45 is ref rod 3. As the knob 21 is turned, from the position shown in Figure 1 to that of Figure 13, the sear release 15 is moved bodily and rearwardly, as a result of which its stud 17 through the spring 27 will shift the link 18 until the link lug 33 abuts the shoulder 34 of the operating rod 3 when the latter is in battery position. Upon continued rotation of the knob 21 to its final position of Figure 13, and due to the link 18 being held against further rearward movement by the shoulder 34, the sear release 15 will be rotated in a clockwise manner on stud 17, causing lug 14 to move away from stop lug 7 and strike the lateral extension 46', as shown in Figure 13.

T o charge the firearm prior to automatic fire, a magazine 60 loaded with cartridges is inserted into the receiver from the underside thereof and thrust upwardly until catch 61 engages the locking notch 85 in such magazine. lf it is desired to re the first round from an open bolt position, the operating rod 3 is then withdrawn rearwardly whereupon bolt Sear 53 under the bias of spring 57 is forced upwardly to engage one of the notches 58 on the underside of bolt 2. A plurality of notches 5S are provided to increase the possibilities of engagement of bolt sear 53 therewith. Such is possible because cam 71 on primary sear 56 is not in engagement with cam 69 of bolt scar 53 as long as trigger 45 is in the normal unpulled position. In such position hammer 44 is held downwardly by bolt 2 and preferably neither primary sear 56 nor secondary sear 46 engages the sear notches of the hammer until bolt 2 moves forwardly to clear hammer 44. When trigger 45 is pulled rearwardly, primary sear 56 is moved forwardly out of the path of sear notch 72 of hammer 44 and secondary sear 46 moved into the path of sear notch 73 of the hammer. Simultaneously bolt sear 53 is cammed out of notch 58 in bolt 2 by cam surface 71 provided on top of primary sear 56. Thus bolt 2 starts its forward counter-recoil movement. Hammer 44 starts to follow bolt 2 forwardly but is held from completing its swing by secondary scar 46 as explained in said patent.

Thus hammer 44 is held in the cocked position by secondary sear 46 until bolt 2 is fully breeched and locked. Shortly before operating rod 3 is in its forward position, however, shoulder 34 on the operating rod 3 engages lug 33 of link 18 thereby pulling such link forwardly. Sear release member 15 is thus rotated rearwardly or clockwise, as viewed in Figure 13, on its stud 17 and simultaneously about the cylindrical portions 12 and 75 to the position shown in Figure 13 by spring 27, as such spring is mounted between sear release 15 and lug 29. It should be noted here that spring 27 also reduces the shock on sear release 15 when operating rod 3 picks up link 18. Slotted hole 32 is provided in link 1S to permit longitudinal movement of such link in the receiver in excess of that which may be actually required, because the accumulation of manufacturing tolerances in the various related components may be considerable. lf, for example, link 18 were pivotally secured to member 15 and such link happened to be somewhat short, considerable over-travel of lug 14 would occur to adversely affect the whole trigger mechanism and possibly also fracture the lug 33. Thus, the length of link 18 may vary within limits and such variance will be compensated for by spring 27 which will then be subject to greater or lesser compression. When sear release 15 is rotated rearwardly, lug 14 on such sear release strikes lateral extension 46' of secondary sear lateral extension 46' thereby forcing such sear rearwardly out of engagement with hammer 44, as shown in Figure 13, thereby permitting hammer 44 to swing forwardly into contact with the ring pin of bolt 2 under the force of the spring biased plunger 52.

It is obvious that the firearm may be converted to a full automatic tire condition at any time by operation of knob 21, independent of the number of rounds remaining in the magazine.

Upon discharge of the cartridge, the operating gases force operating rod 3 rearwaldly away from lug 33 of link 18. The spring 27 is then free to expand to rotate the sear release 15 in a counterclockwise direction on the stud 17 and out of engagement with the lateral eX- tension 46 of the secondary sear and into contact with the stop lug 7, causing the link 18` to be moved a short distance to the rear. The secondary sear 46 will then re-engage the hammer 44 permitting the bolt to move forwardly, chamber the next cartridge, and lock before hammer 44 will again be released as above described and shown in Figure 13.

If at any time it is desired to stop firing while firing full automatic, it is merely necessary to release trigger 45. Upon such release of such trigger, primary sear 56 engages sear notch 72 of the hammer to hold it in cocked position and bolt sear 53 is immediately raised by the spring 27 into contact with the underside 2 of bolt 2 when the bolt recoils whereupon it engages one of the notches 58 on the underside of bolt 2 thereby holding such bolt in the rearward position. In the event trigger 45 is released during the forward movement of bolt 2 during automatic fire, no different functioning will be experienced because bolt 2 reciprocates so very rapidly that such bolt will have closed and link 18 will have actuated sear release 15 to release hammer 44 and discharge the cartridge before primary scar 56 could engage the hammer. Thus bolt 2 will be forced rearwardly upon discharge of the cartridge to be held in the open position at the rearmost recoil position regardless of when the trigger is released. Firing is readily resumed by simply pulling trigger 45. When the magazine is empty, the bolt is held open by the bolt engaging the magazine follower 70 which rises into the path of the bolt after the last round is fired.

Thus from the foregoing description it is readily apparent that a simple and sturdy fire control mechanism having both semi-automatic and full-automatic operation and one that will not permit premature ignition of a cartridge is hereby provided. In addition such mechanism will likewise restrain bolt 2 in the open position in full automatic fire to permit more rapid cooling of the barrel.

I claim:

l. In an automatic firearm having a receiver and a reciprocating member, in combination, a spring pressed hammer arranged to strike a firing member, a Sear engageable with said hammer to secure said hammer in a cocked position, a sear release member movably mounted on the firearm and cooperating with said sear to move said sear out of engagement with said hammer, a link slidably mounted on said receiver for movement with said reciprocating member as said reciprocating member approaches its battery position, and a compressed spring interposed between said link and said scar release member whereby forward movement of said link is transmitted without shock to said sear release member to release said sear from said hammer.

2. In a firearm of the automatic type having a receiver, an operating member reciprocable rearwardly from, and forwardly to, a battery position, a spring pressed hammer arranged to strike a cartridge firing member, a sear movably mounted on the firearm and engageable with said hammer to hold said hammer in a cocked position, a sear release member, eccentric means for pivotally mounting said sear release member to the firearm in either of two linearly displaced, manually selectable p0- sitions, hereinafter referred to as the automatic and semiautomatic positions respectively, a sear engaging por tion on said sear release member engaging said sear in said automatic position, whereby pivotal movement of said sear release member disengages said sear from said hammer, a link slidably mounted on the receiver for reciprocable movement, and a compressed spring interposed between said link and said sear release member whereby said spring moves said sear release member in a sear releasing direction, said link having a portion thereof disposed adjacent to the path of movement of said operating member and constructed and arranged to be engaged and moved by said operating member as said operating member moves forwardly into its battery position only when said Sear release member is in its automatic position.

3. The combination defined in claim 2 wherein the last mentioned means comprises a compressed spring interconnecting said link and said Sear release member, said spring being spaced from the means interconnecting said link and said sear release member.

4. In an automatic firearm having a receiver, a bolt, a firing pin and an operating rod mounted on the receiver for reciprocable movement, the improvement comprising, in combination, a spring pressed hammer pivotally mounted in said receiver, a pivotally mounted sear engageable with said hammer to secure said hammer in a cocked position, a mounting pin rotatably mounted in said receiver and having an eccentric portion formed thereon, a sear release member pivotally mounted on said eccentric portion, means for manually rotating said mounting pin between two 180 displaced positions whereby said sear release member may be selectively located in either of two displaced positions hereinafter referred to as the automatic and semi-automatic positions respectively, a sear engaging portion on said sear release member constructed and arranged to move said scar out of engagement with said hammer by pivotal movement of said sear release member and means for so pivoting said sear release member comprising a link slidably mounted on said receiver for movement parallel to said operating rod, a connection between said link and said sear release member whereby the battery position of said link relative to said operating rod is shifted by rotation of said mounting pin, and a projecting portion on said link arranged to lie in the path of movement of said operating rod when said scar release member is in the automatic position and to be held out of such path when said sear release member is in the semi-automatic position.

5. In an automatic firearm having a receiver, a bolt, a firing pin and an operating rod mounted on the receiver for reciprocable movement, the improvement comprising, in combination, a spring pressed hammer pivotally mounted relative to said receiver, a pivotally mounted sear engageable with said hammer to secure said hammer in a cocked position, a mounting pin pivotally mounted in said receiver and having an eccentric portion formed thereon, a sear release member pivotally mounted on said eccentric portion, resilient means for biasing said mounting pin axially relative to the receiver, a rectangular head portion on said mounting pin arranged to be resiliently held in a slot in said receiver, a grasping portion on said mounting pin disposed exteriorly of the receiver whereby said mounting pin may be manually located in either of two 180 angularly displaced positions to position said sear release member in either of two displaced positions hereinafter referred to as the automatic and semi-automatic positions respectively, a Sear engaging portion on said scar release member constructed and arranged to move said sear out of engagement with said hammer by pivotal movement of said sear release member and means for so pivoting said sear release member comprising a link slidably mounted on said receiver for movement parallel to said operating rod, a connection between said link and said sear release member whereby the battery position of said link relative to said operating rod is shifted by rotation of said mounting pin, and a projecting portion on said link arranged to lie in the path of movement of said operating rod when said sear release member is in the automatic position and to be held out of such path when said sear release member is in the semi-automatic position.

6. ln a firearm of the automatic type having a receiver, a boit having a notch thereon and reciprocable in said receiver and a firing pin in the bolt, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the tiring pin in the battery position of the bolt, a hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt seaipivotally mounted on said hammer and constructed and arranged to engage said notch to hold the bolt in a recoiled position, said hammer sea-r cooperating with said bolt scar to release said bolt sear substantially simultaneously with the release of said hammer sear, and means for releasing said hammer sear.

7. in a rearm of the automatic type having a receiver, a bolt reciprocable therein and a tiring pin in the bolt, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the tiring pin in the battery position of the bolt, a hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer and constructed and arranged to hold the bolt in a recoiled position, said hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said hammer scar, and means for releasing said hammer sear.

8. ln a firearm of the automatic type having a receiver, a bolt having a notch thereon and reciprocable in said receiver and a tiring pin in the bolt, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike tbe ring pin in the battery position of the bolt, a hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer constructed and arranged to engage said notch to hold the bolt in a recoiled position, said hammer sear cooperating with said bolt sear to release said -bolt sear substantially simultaneously with the release of said hammer sear, and a trigger operatively connected to said hammer sear to release said hammer sear by pulling movement of said trigger.

9. ln a rearm of the automatic type having a receiver, a bolt reciprocable therein and a ring pin in the bolt, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the tiring pin in the battery position of the bolt and to be cocked by recoil movement of the bolt, said hammer having a bifurcated end portion, a sear notch formed in said bifurcated end portion, a hammer sear pivotally mounted on the firearm having a body portion projecting between the said bifurcated portions of said hammer in the cocked position thereof and a sear portion engaging said hammer sear notch to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer between the said bifurcated portions having a bolt engaging portion arranged to hold the boit in a recoiled position and a hammer scar engaging portion disposed in the path of releasing movement of said hammer Sear, whereby said bolt sear is released by said hammer sear, and means for releasing said hammer sear.

l0. The combination defined in claim 9 and a spring mounted between said bolt sear and said hammer and arranged to bias said bolt sear in a bolt engaging direction and a stop for limiting the movement of said bolt .sear produced by said spring.

ll. In a irearm of the automatic type having a receiver, a bolt reciprocable therein, a tiring pin in the bolt, and a reciprocating operating member, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the tiring pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotl@ ally mounted on said hammer constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said primary hammer sear, means for moving said primary hammer sear in a releasing direction, a secondary hammer scar pivotally mounted relative to the receiver, means interconnecting said primary and secondary sears for moving said secondary sear into a hammer engaging position as said primary sear is moved to a hammer releasing position, a sear release member fmovably mounted on the firearm and cooperating with said secondary sear to move said secondary Sear out of a hammer engaging position, and a link operatively connected between said sear release member and said reciprocating operating member whereby movement of said reciprocating operating member to its battery position operates said sear release member to move said secondary sear from its hammer engaging position.

12. ln a firearm of the automatic type having a receiver, a bolt reciprocable therein, a tiring pin in the bolt, and a reciprocating operating member, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the firing' pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said -hammer and constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt Sear substantially simultaneously with the release of said primary hammer Sear, means for moving said primary hammer Sear in a releasing direction, a secondary hammer sear pivotally mounted relative to the receiver, means interconnecting said primary and secondary sears for moving said secondary scar into a hammer engaging position as -said primary sear is moved to a hammer releasing position, a linkage interconnecting said secondary sear and the reciprocating member whereby said secondary sear is disengaged from said hammer by movement of the reciprocating member to its battery position, and means for selectively connecting and disconnecting said linkage from operative relationship with said reciprocating operating member.

13. In a iirearm of the automatic type having receiver, a bolt reciprocable therein, a tiring pin in the bolt, and a reciprocating operating member, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the firing pin in the battery position of the bolt, a primary hammer scar constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer and constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said primary hammer sear, means for moving said primary hammer Sear in a releasing direction, a secondary hammer scar pivotally mounted relative to the receiver, means for interconnecting said primary and secondary sears for moving said secondary scar into a hammer engaging position as said primary sear is moved to a hammer releasing position, a sear release member pivotally mounted on the firearm and having a sear engaging portion cooperating with said secondary sear to move said secondary sear out of engagement with said hammer, a link mounted on the firearm for reciprocating movement, means for operatively connecting said link to said sear release member, said sear release member being pivotable to selectively move said link between a first position wherein a portion of said link is engaged and moved by said reciprocating member as said member approaches its battery position, and a second position wherein said link is free of said reciprocating member for all positions of the latter.

14. In a rearm of the automatic type having a receiver, a bolt reciprocable therein, a firing pin in the bolt, and a reciprocating operating member, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the tiring pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said primary hammer sear, means for moving said primary hammer sear in a releasing direction, a secondary hammer sear pivotally mounted relative to the receiver, means interconnecting said primary and secondary sears for moving said secondary sear into a hammer engaging position as said primary sear is moved to a hammer releasing position, a sear release member, eccentric means for pivotally mounting said sear release member to the rearm in two linearly dis- Y placed, manually selectable positions, a sear engaging portion on said sear release member cooperating with said secondary sear in the iirst of said selected positions of said sear release member whereby pivotal movement of said sear release member disengages said secondary sear from said hammer, and a link movably mounted on the irearm and operatively connected to said sear release member whereby said link can pivotally move said sear release member in a sear releasing direction, said link having a portion thereof projecting into the path of and movable with said reciprocating member as said reciprocating member approaches its battery position.

15. In a firearm of the automatic type having a receiver, a bolt reciprocable therein, a tiring pin in the bolt, and a reciprocating operating rod, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the firing pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said primary hammer sear, means for moving said primary hammer sear in a releasing direction, a secondary hammer sear pivotally mounted relative to the receiver, means interconnecting said primary and secondary sears for moving said secondary sear into a hammer engaging position as said primary sear is moved to a hammer releasing position, a mounting pin rotatably mounted in said receiver and having an eccentric portion formed thereon, a sear release member pivotally mounted on said eccentric portion, means for manually rotating said mounting pin between two 180 displaced positions whereby said sear release member may be selectively located in either of two displaced positions hereinafter referred to as the automatic and semi-automatic positions respectively, a sear engaging portion on said sear release member constructed and arranged to move said secondary sear out of engagement with said hammer by pivotal movement of said sear release member and means for so pivoting said sear release member comprising a link slidably mounted on said receiver for movement parallel to said operating rod, a connection between said link and said sear release member whereby the battery position of said link relative to said operating rod is shifted by rotation of said mounting pin, and a projecting portion on said link arranged to be in the path of movement of said operating rod when said sear release member is in the automatic position and to be held out of such path when said sear release member is in the semi-automatic position.

16. The combination defined in claim l wherein the last mentioned means comprises a compressed spring kinterconnecting said link and said sear release member.

17. In a firearm of the automatic type having a receiver, a bolt reciprocable therein, a tiring pin in the bolt, and a reciprocating operating member, the improvement comprising a spring pressed hammer pivotally mounted relative to the recevier and arranged to strike the ring pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said primary hammer sear, a trigger operatively connected to said primary hammer sear to release said primary hammer sear by pulling movement of said trigger, a secondary hammer sear pivotally mounted on said trigger and arranged to be moved into a hammer engaging position as said trigger is pulled to release said primary sear, a sear release member movably mounted on the rearm and cooperating with said secondary sear to move said secondary hammer sear out of engagement with said hammer, and a link operatively connected between said sear release member and said reciprocating member whereby movement of said reciprocating member to its battery position operates said sear release member to release said secondary sear from said hammer.

18. In a rearm of the automatic type having a receiver, a bolt reciprocable therein, and a reciprocating operating member, a tiring pin in the bolt, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the tiring pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said hammer sear, a trigger operatively connected to said primary hammer sear to release said primary hammer sear by pulling movement of said trigger, a secondary sear pivotally mounted on said trigger and arranged to be moved into a hammer engaging position as said trigger is pulled to release said primary sear, a sear release member pivotally mounted on the firearm and having a sear engaging portion cooperating with said secondary sear to move said secondary sear out of engagement with said hammer, a link mounted on the rearm for reciprocating movement, means for operatively connecting said link to said sear release member, said link having a portion disposed in the path of movement of said reciprocating member, and means for selectively shifting the pivotal position of said sear release member whereby said link portion may be moved into the path of said reciprocating member to be actuated thereby as the reciprocating member approaches its battery position.

19. In a firearm of the automatic type having a receiver, a bolt reciprocable therein, a tiring pin in the bolt, and a reciprocating operating rod, the improvement comprising a spring pressed hammer pivotally mounted relative to the receiver and arranged to strike the ring pin in the battery position of the bolt, a primary hammer sear constructed and arranged to hold said hammer in a cocked position, a bolt sear pivotally mounted on said hammer constructed and arranged to hold the bolt in a recoiled position, said primary hammer sear cooperating with said bolt sear to release said bolt sear substantially simultaneously with the release of said primary hammer sear, a trigger operatively connected to said primary hammer sear to release said primary hammer sear by pulling movement of said trigger, a secondary sear pivotally mounted on said trigger and arranged to be moved into a hammer engaging position as said trigger is pulled to release said primary sear, a mounting pin rotatably mounted in said receiver and having an eccentric portion formed therein, a sear release member pivotally mounted on said eccentric portion, means for manually rotating said mounting pin between two 180 displaced positions whereby said sear release member may be selectively located in either of two displaced positions hereinafter referred to as the automatic and semi-automatic positions respectively, a sear engaging portion on said sear release member constructed and arranged to move said secondary sear out of engagement with said hammer by pivotal movement of said sear release member and means for so pivoting said sear release member comprising a link slidably mounted on said receiver for movement parallel to said operating rod, a connection between said link and said sear release member whereby the battery position of said link relative to said operating rod is shifted by rotation of said mounting pin, and a projecting portion on said link arranged to lie in the path of movement of said operating rod when said sear release member is in the automatic position and to be held out of such path when said sear release member is in the semi-automatic position.

20. The combination dened in claim 19 wherein the last mentioned means comprises a compressed spring interconnecting said link and said sear release member.

21. In an automatic firearm having a receiver, a bolt slidably mounted for reciprocable longitudinal movement in the receiver, an operating rod slidably mounted on the receiver and connected to the bolt to operate the same, a hammer pivotally mounted on the receiver, a sear associated with the hammer and engaging and holding the hammer in the cocked position thereof, a sear tripping mechanism comprising a sear release member pivotally mounted on the receiver, a rst depending lug on said sear release member engageable with the sear, said sear release member having an arm thereon, a shaft-like link mounted for limited longitudinal movement on the receiver, a second lug on the forward end of said link arranged to be engaged by the operating rod on the counterrecoil stroke thereof, means connecting said link to said sear release member whereby forward movement of said link rocks said sear release member to disengage the sear from the hammer thereby automatically tripping the hammer, and means for selectively positioning said sear release member whereby said second lug can be moved out of engagement with the operating rod for all positions of said rod to obtain semi-automatic re.

22. The combination deined in claim 21 wherein said connecting means comprises a helical spring mounted at the rear of said link, one end of said spring abutting said sear release member, said link having a longitudinally disposed slot in the rear end thereof, and said arm of said sear release member having a stud thereon slidably mounted in said slotted slot, said slot permitting slight compression of said spring prior to said spring effecting pivoting of said release member.

23. In an automatic irearm having a receiver, a bolt slidably mounted for reciprocable longitudinal movement in the receiver, an operating rod slidably mounted on the receiverand connected to the bolt, a hammer pivotally mounted on the receiver, a sear associated with the hammer and engaging and holding the hammer in the cocked position thereof, a sear tripping mechanism comprising a sear release member pivotally mounted on the receiver, a iirst depending lug on said sear release member engageable with said sear, said sear release member having an arm thereon, a stud on said arm, a link consisting of a shaft-like member having enlarged ends, each of said enlarged ends being provided with a longitudinally disposed slot therein, said rearmost slot receiving said stud and said other slot being engageable by a transverse pin in the receiver to slidably mount said link for limited longitudinal movement on the receiver, a second lug on the forward end of said link arranged to be engaged by the operating rod on the counter-recoil stroke thereof, a

spring connecting said link to said sear release member whereby forward movement of said link rocks said sear release member to disengage the sear from the hammer thereby automatically tripping the hammer, and means for selectively positioning said sear release member whereby said second lug can be moved out of engagement with the operating rod to obtain semi-automatic lire.

24. In a rearm adapted for semi-automatic or automatic tire having a receiver, a bolt slidably mounted in the receiver for longitudinal reciprocal movement, an operating rod connected to the bolt, a hammer pivotally mounted on the receiver, a trigger associated with the hammer and a primary sear on the trigger constructed and arranged to engage and hold the hammer when the trigger is in the released position, a secondary sear associated with the trigger and manually operable thereby to engage and hold the hammer in the pulled position of the trigger, in combination, a sear tripping mechanism comprising a sear release member pivotally mounted on the receiver, a first depending lug on said sear release member engageable with the secondary sear to release the same from said hammer, a shaft-like link mounted for limited longitudinal movement on the receiver, a second lug on the forward end of said link arranged to be engaged by the operating rod on the counter-recoil stroke thereof, means connecting said link to said sear release member whereby forward movement of said link rocks said sear release member to disengage the secondary sear from the hammer thereby automatically tripping the hammer, and means for selectively positioning said sear release member whereby said second lug can be moved into or out of the path of a portion of said operating rod to obtain automatic or semi-automatic fire.

25. In a firearm adapted for semi-automatic or automatic fire having a receiver, a bolt slidably mounted in the receiver for longitudinal reciprocal movement, an operating rod connected to the bolt, a hammer pivotally mounted on the firearm, a trigger associated with the hammer, a primary sear on the trigger constructed and arranged to engage and hold the hammer when the trigger is in the released position, a secondary sear associated with the trigger and manually operable thereby to engage the hammer in the pulled position of the trigger, in combination, a sear tripping mechanism comprising a sear release member pivotally mounted on the receiver, a rst depending lug on said sear release member engageable with the secondary sear, said sear release member having an arm thereon, a headed transverse stud on said arm, a link consisting of a shaft-like member having enlarged ends, each of said enlarged ends being provided with a longitudinally disposed slot therein, said rearmost slot being engageable by said stud to slidably mount said link for limited longitudinal movement on the receiver, a second lug on the forward end of said link arranged to be engaged by a portion of the operating rod on the counter-recoil stroke thereof, a spring connecting said link to said sear release member whereby forward movement of said link rocks said sear release member to disengage the secondary sear from the hammer thereby automatically tripping the hammer, and means for selectively positioning said sear release member whereby said second lug can be moved into or out of the path of said portion of the operating rod to obtain automatic or semi-automatic tire.

26. In a firearm, a receiver, a bolt reciprocable in said receiver, a hammer pivoted in said receiver and constructed and arranged to be moved to cocked position by retraction of said bolt, and a bolt sear pivoted on said hammer and engageable with said bolt to hold the same in retracted position.

27. A firearm as recited in claim 26, said hammer having primary and secondary sear notches, a trigger pivoted in said receiver, a primary sear on said trigger and engageable with said primary sear notch -to hold said hammer cocked only when said trigger is released, and

a secondary sear pivoted on said trigger and engageable with said secondary sear notch to hold said hammer cocked only when said trigger is pulled, said primary sear engaging and releasing said bolt sear when said trigger is pulled.

28. A iirearm as recited in claim 27, and means responsive to movement of said bolt to battery to engage and release said secondary sear from said hammer.

References Cited in the file of this patent UNITED STATES PATENTS Schouboe Nov. 27, McClean Sept. 7, Schouboe June 26, Clark June 24, Lang Mar. 9,