US2785605A

US2785605A - Firing mechanism for automatic rifles

Info

Publication number: US2785605A
Application number: US281746A
Authority: US
Inventors: Jourdat Marc
Original assignee: SARL GEVARM
Current assignee: A RESPONSABILITE GEVARM Ltee Ste; SARL GEVARM
Priority date: 1951-04-17
Filing date: 1952-04-11
Publication date: 1957-03-19
Anticipated expiration: 1974-03-19
Also published as: CH297884A

Description

March 19, 1957 M. JOURDAT FIRING MECHANISM FOR AUTQMATIC vPalmas Filed April 11. 1952 2 Sheets-Sheet 1 mms hvcof vla/m JAHormey-b?? March 19, 1957 M.'JouRDA1' 2,785,605

FIRING MECHANISM FOR AUTOMATIC RIFLES Filed April 11, 1952 2 Sheets-smeet 2 jssos inmNG MECHANI'SM Fon AUTOMATIC RiFLEs Marc Jourdat, St.-Etienne,Y France, assignor to Societe a responsablite limitee Gevarm, Saint-Etienne (Loire), France, a French corporation Application April 11, 19527, Serial No. 281,746 Claims priority, application France April 17, 1951 3 Claims. (Cl. 89-140) t Automatic ries asproduced hitherto include an intri- "cate mechanism, the parts of which are ditiicult to machine and are consequently expensive.

The automatic rifle forming the object of my invention has for its object to remove these drawbacks and comprises a bolt chamber to the front of which is screwed the gun barrel and wherein the actual rie bolt is slidably litted and urged forwardly by a spring while the bolt carries at its front a rod-shaped extension adapted to strike the cartridge in the barrel, said rod-shaped extension being slidingly fitted inside an extension of reduced diameter of the bolt chamber while there is pivotally secured to a carrier member or receiver rigid with the bolt chamber a tumbler adapted to release the rie bolt out of its `rear inoperative position when said tumbler is released by the trigger.

Y Accompanying drawings illustrate by way of example a preferred embodiment of my invention. In said drawings:

Fig. l is a longitudinal cross-section of the rie illustrated in its cocked position before firing.

Fig. 2 is a cross-section thereof through line II--II of Fig. 1.

Fig. 3 is a longitudinal cross-section of the rifle shown at the moment of the automatic positioning of the cartridge just before tiring.

Fig. 4 is a partial cross-sectional view of the cocking means for the rille bolt before the latter recoils or kicks.

Fig. 5 illustrates in longitudinal cross-sectional view the rie at the moment of the recoil of the rie bolt and of the automatic ejection of the empty cartridge case.

Fig. 6 is a cross-section through line VI-VI of Fig. 5.

Fig. 7 is an outer plan view corresponding to Fig. 5.

Fig. 8 shows the cocking device for the rifle bolt in the case of the tiring of a burst.

Fig. 9 is a perspective view ofthe rocking spindle controlling selectively the tiring of a burst or of separate shots.

, to slide in said b olt chamber and is arrested in its forward movement by the shoulder between the two elementary chambers. The bolt.3 includes a cylindrical body 31 that is slidingly itted inside the large diameter chamber 2 and Y a front extensionassuming the shape of a cylindrical rod 32 acts asa piston inside the front chamber 21 the inner diameter of which corresponds to the diameter of the bead of the cartridge. The bolt 3 carries a cocking lever K 4 (Fig. 7) that projects outwardly of the chamber 2,

while it is longitudinally guided inside a slot 23 of the latter.

The forward stroke of the bolt 3 is obtained by means of the coil spring 5 that is wound round the shouldered .United States Patent O i 2,785,605 PatentedfMar. y19,1957

rod 6 engaging an axial bore provided in the bolt and in Vor charger 8 designed in the conventional manner may enter it, said charger being secured through a rocking bracket 9 pivotallyv carried by a parallelopipedic carrier or receiver 10 extending underneath the bolt chamber.

The carrier 10 is rigidly secured to the chamber! by means of a screw 11 or any other suitable means. This carrier includes at its rear end a trigger guard 12 and it is recessed at 101 in order Yto house the automatic cocking device.

This automatic cocking device includes a trigger 13 that is submitted to the vertical thrust of a coil spring 131. VThis trigger 13 is housed inside the carrier 10 and it is pivotally secured over a transverse pivot pin 14 enlsaid pivot pin engaging a vertically elongated port 152 `in said trigger plate.

The sear 15 is provided in its lower portion with a further elongated port 153 through which passes an angularly shiftable spindle or pivot pin 17 through which it is possible to produce the firing either as a burst or as a series of separate shots. The sear 15 is also subjected to the action of a coil spring 18 engaging a stud 19 on the carrier 10 and adapted to urge the sear forwardly and to the action of a compressed coil 20 urging the sear upwardly into its cocked position.

In order to cock the rie, the bolt is urged rearwardly either by hand through actuation of the cocking lever 4 or automatically as described hereinafter, until the shoulder 33 on the bolt is engaged by the upper end of the scar 15. The latter that forms a stop, that is capable of receding, rocks with reference to the pivot pin 16 under the action of the torque generated by the spring 5 urging the bolt forwardly until the front surface of the elongated opening 153 in the rocking sear abuts against the at side of the oblong spindle 17 as illustrated by the arrow A of Fig. 1.

When tiring (see Fig. 3) and upon depression of the trigger 13 in the direction of the arrow B of Fig. 3 the 50 sear 15 rocks as shown by the arrow C and it revolves round the pivot pin 16 until the front shoulder 33 of the bolt is'released by said scar. However, the trigger 13 is provided on its upper surface with an adjustable screw 22 that abuts just before the release of the bolt 3 against the lower surface of the bolt chamber 2 whereby, after contact of said lower surface with the screw 22, a continued depression of the trigger 13 produces a further angular shifting thereof by reason of the clearance of the pivot pin 14 with reference to the port 132.

This further shifting of the trigger is felt by the hunter using the rie, by reason of the different values of the engages thechamber 11 .of the gun barrel 1 until the .bead ofthe .cartridge .is in contact with the` rear en d of the barrel 1. At this moment, the sudden stopping of the cartridge X provides the desired percusslon by .reason of. theinertiadeveloped by the high speed movement of the bolt. The rod3?,is provided at its end with a .projecting nose 34V .that strikes the. cartridge along Vits annular surface.

After the firing, the pressure of the explosion gases urges rearwardly the bolt A3 while `the cartridge case is extracted and ejected automatically. s

To this end and as shown in Fig. 5, the bolt 3 as it moves rearwardly uncovers the flaring lateral opening 25 in the bolt chamber 2. The empty case urged rearwardly `together with the bolt 3 escapes then suddenly through thelsaid opening 25, is blownoutwardly and ejected.

AWhen the iringis atan end (Fig-4) the sear A15 is urged by th-e coil springs 18l and 20, into Va pivotingrmotion with reference to thepivot pin 1,6 in the direction of the arrow D. During this pivotal movement, the nose 15l of the sear releases the nose 133 of the trigger 13 whereby said trigger and sear no longer engage each other. The sear 15 is thus urgedvertically'by the springs 18 and 20' which allows a further Vautomatic cooking of the rifle after the recoil of the bolt 3 to the rear of the Sear. The trigger 13 which` lis now released by the automatic cocking device isv returnedto its tiringposition by the spring 131. The movement of the sear 15 which any rocking of the latter. In this position, theactuation of the trigger 13 only provides for the vertical shifting of the Sear 15 as shown by the direction of the arrows E and consequently this produces a burst firing, as no .pre-

liminary action on the trigger is then required.

The automatic rifle according tomy invention is of an extremely simple execution by reason of thesimple nature of its different parts most of which may beobtaiued by turning from the bar orthe like standard mechanical operations.

On the other hand, this rifle includes none fof the standard members known and used hitherto .such asthe extractor, the ejector, ythe movable striker, theslope feedi ing the barrel and the like.

What Inclaim is:

1. inan automatic rifle, in combination: a bolt chamber; a bolt slidable inrsaid chamber; a main spring in said chamber and urging said bolt forward; a receiver rigid with said chamber; a Sear memberin said receiver-normally engagingthe boltagainst the action of said spring; in said sear member, a first velongated* slot substantially orthogonal to the bolt; la first pivot pin rigidwith said receiver, said first slot .engagingsaid pivot pin and being adapted to slide on said pivot pin in directions substantially orthogonal to the bolt; a trigger in said receiver, adapted to engage yieldingly said sear member and movable with respect to saidsear member; in said trigger, a second elongated slot substantially orthogonal to-the bolt; a second pivot pin rigid with said receiver and engaging said second slot, whereby said trigger is adapted to slide over said second pivot pin in directions substantially orthogonal Ato the bolt; said trigger being held directly by said sear member when theY latter engages the bolt against the action of the main spring; said trigger being adapted, upon depression, to release, said sear member from -engagement with they bolt; at least one spring means Vbetween said receiver and said sear member and adapted to urge ,said scar member against the V`bolt upon recoil thereof, and to control the operative and inoperative positions of said sear member relative to the bolt, the bolt chamber and the trigger; said bolt, during its forward and recoil directions of rnotion,-` urging said sear member outside said bolt chamber until said bolt has returned to lits rearward inoperative position, at which said one spring means urges said sear member in locking engagement with .said bolt, and at which said trigger has been released from engagement with said sear member and lreturned. to its inoperative position.

2. InA an automatic rifle, thecombination as claimed in claim 1, comprising further: elastic means between the bottom-wall of said receiver andthe lower face of said trigger, forward of said second pivot pin and adapted to urge said trigger upwards over said second pivot pin; an adjustable screw projecting from the upper face of Vsaid triggerrearwards of ysaid second slot, and adapted lto abut against `the lower surface .of said bolt chamber upon rocking of said trigger around said secondpivot pin during the early stage of depression of said trigger priorg to the release ofthe bolt; the duration of said early stage being controlled bythe height of the projection Vof said screw out of said lupper face; whereby, during a continued depression of s aidV trigger beyond ysaidiearlystage, said screw causes the forward endof said .trigger to vpivot around said .Second pivot pin against the ationof .said elastic means, therebyausing said trigger .to actuate said sear member to release said bolt and lin- `dicatping Ato the user the precise timing of boltrelease and striking in relation to the earlyvstage and continued A depressions respectively of said trigger.

3. ln an automatic rie, the r,cornbination as claimed i .inclaim l, comprising furtherzfinsaiddsear member, a

'thirzd elongated slot disposed below, 4and substantially coaxial with, said first slot, and substantially orthogonal ,tosaidvboln a rotary. spindle supported by the Walls 0f said receiver and passing through said.l third s1ot; said third slotl having a transverse width substantiallygreater than that of said rst slot; said spindle having two 4fiat .parallel sidewalls forming an intermediate portion 1ocated within the walls of said .receiver and adaptedu to cooperate with said third slot; the width ofjsaidintermediate portion being substantially equal to the transverse width of said third slot; hand operated means connected to said spindle and adapted .to shift said .spindle into a yfirst position for which theat side wallsofrsaid intermediate portion are substantially .orthogonal to said gbolt, thereby/allowing shiftingand biasing of said sear `member around said first pivot pin, and into ya second .alternative position for which said fiatv side .walls of said intermediate portion `extend transversely acrosssaid third slot and engage the side walls of said .third slot to allow only a vertical shifting ofv .said sear member, whereby said automatic rifle may be operated for burst .firing when said spindle is in said second position and .for controlled firing when `said spindle is insaid .first position.

References YCited in the file .of this patent vUi`U'lfl-D STATES PATENTS Great Britain Oct. 6, Y1937