US2116139A

US2116139A - Firing mechanism for automatic firearms

Info

Publication number: US2116139A
Application number: US11791A
Authority: US
Inventors: Marriner A Browning
Original assignee: J M & M S Browning Co
Current assignee: J M & M S Browning Co
Priority date: 1934-04-10
Filing date: 1935-03-19
Publication date: 1938-05-03
Anticipated expiration: 1955-05-03
Also published as: US2116140A

Description

May 3, 1938. M. A. BROWNING FIRING MECHANISM FOR AUTOMATIC FIREARMS Original Filed April 10. 1934 2 Sheets-Sheet l w m mm 5,2m www, M vm I -H -l .ww

May 3, 1938.. M. A. BROWNING FIRING MECHANISM FOR AUTOMATIC EIREARMS Original Filed April 10, 1934 2 Sheets-Sheet 2 Z: DFHEV Jhr/anta?" @Y JM Patented May 3, 193s `UNITE STATES PAT E N T OFFICE FIRING MECHANISM FOR AUTOMATIC .FIREARMS Marriner A. Browning, Ogden, Utah, assig'nor to J. M. & M. S. Browning Company, Ogden, Utah, a corporation vof Utah 15 Claims.

One object of the invention is to provide an improved Yhammer mechanism which is controlle. directly by the main operating slide so as to insure the closing of the breech before fir- ,5 ing occurs.

-Another object of the invention is to provide an improved retarding mechanism whereby the gun may becaused to operate at a slower speed than it otherwise would.

.10 vThis present application constitutes a division of myecopending application for Automatic irearm, Serial No. 719,862, filed April 10, 1934, which said co-pending application was issued as Patent No. 2,093,704on September 21, 1937.

15 Inthe accompanying drawings I have shown the embodiment of the inventionwhich I now deem preferable, but -it will be understood that the drawings are intended for illustrative purposes only and are not to be relied upon as limit- 20 ingor defining the scope of the invention, the

claims forming a part of this specication being relied upon for that purpose.

Of the drawings:

Fig. y1 is a side view Vof a firearm embodying the invention.

-Fig2 is an enlarged fragmentary view of the rear portion of the firearm, this View being partly :a side view and partly a longitudinal sectional view.

y30 Fig. 3 is a View similar to Fig. 2 but showing ythe parts in different relative positions.

Fig. i is a transverse sectional uiew taken 'along the line-ll-- of Fig. 3.

Fig. 5 is afragmentary view similar to a rear 35 portion of'Figs. 2 and 3, and showing the retardying mechanism in an intermediate position.

, Fig. 6,is a View similar-'to Fig. 5, but showing Atliefretarding mechanismin its hammer releas- -.ing position.

,.40 Y "Fig, 7 is a View similar to Fig. 5, but showing :the retarding mechanism reset by a cam on the operating slide.

Fig. 8 is an enlarged fragmentary view-.taken alongthe line-S-Boi Fig. 6.

- 45 Fig. 9 is a cross sectional View taken on the line .55 Asshown the casing is formed from a single piece of steelalthough I do not necessarily limit myself to this integral construction. The portion Ia of the casing is formed to receive the rear end of 4a barrel 2. Behind'the portion Ia are two main side walls Ib, Ib Aconnected near the 5 center by an integral cross member I, An opening Id is. provided at the front'of the cross member lc, which opening is normally closed by a-.pivoted Vcover V3 heldby a releasable latch 3a. An opening is providednat the rear of the cross 10 member, .whichopening is closed by a plate 4. Thebottomiof the casing is normallyclosed by separate plates `5 and-6. The rear of the casing is normally closed by a plate `'l flanged at its sidesand having ribs (not shown) adapted to enter grooves formedin the side walls lb, Ib. A suitable. latch `lbserves to normallyhold the end plate 1.in place. Carried by the plate 1 at opposite sides .thereofare two brackets 8, 8 carrying handles 9, 9.

The casingfl is provided .withan integral eX- tension le -which extends forward underneath the barrel. .This extension is hollow and it serves to engage and retain -a piston vtube i6. At its forward end lthe tube IBisconnected with, and supported by, the barrel. Longitudinally movable along-thebottom ofthe main casing is an operating slide 21, this-s1ide being connected with -fa piston 29 and a piston rod.28 positioned within'thepistontube I6. A cylinder ,3| is pro- 30 vided in the forwardfendY of the. tube vI6, and the piston raccurately ts. the said cylinder. A gas v,passage extends fromthe vbore of the barrelto the'cylindento enable-the gaseseof explosion to Fenter the cylinder and .aci-upon the piston to Yforce it'rearward. Y For-ireturning-the slidefin theforward direction afterfhavingvbeen moved rearward by the Ypiston and piston rod, there is provided an action springz32 supported upon'and guidedby a rod 40 -33. Preferably the spring and rod 32 and 33 extendintoa hollowV buii'er 34 carried by the rear vplate `1. Thespring at its rear end abuts. against 'a head,35 detachably secured inplace in the buiier. The spring at-its forward endv extends into an Yaperture in the slide 21 and abutsagainst a shoulder v.3b. A hole provides clearance for the rodl 33 when the slide is in its rear position. The slide 2'! serves. to operate the feeding, loading andring mechanisms of the gun.

Extending transversely through the casing below the rear portionv ofy the barrel is a cartridge feed rchannel 31 adapted for the-reception of a Acartridge belt such as A. Transversely movable `below the feed ychannel 31 is a feed slide39, 55

which is actuated by means of the operating slide 21. As shown, the main portion of the feed slide is below the operating slide, and in this case the operating slide has a cam groove in its lower face into which projects a pin carried by the feed slide. The shape of the groove is such that the feed slide is reciprocated transversely as the operating slide reciprocates longitudinally. The feed slide carries a pawl which engages the cartridge belt to bring a new cartridge into a position below the barrel at each actuation of 'the operating slide.

Preferably the operating slide 21 and the parts associated therewith are removable from the rearm at the rear thereof. Toeffect such removal it is necessary first to remove the spring 32 and the rod 33 and to then remove the end plate 1 with the parts carried thereby. The slide is then substantially free to be withdrawn in the rearward direction, except for the fact that the pin on the feed slide must be disengaged from the groove in the operating slide.

'Ihe firearm is provided with a reciprocating breech bolt 45 which is guided between the side walls Ib, Ib of the casing. The breech bolt is operated and controlled by mechanism operated by the slide 21, this mechanism being similar to that disclosed in Patent No. 1,293,022 to John M. Browning.- As shown in Fig..3 the breech bolt 45 is connected with the slide 21 by means of two links 46 and 41 pivotally connected with each other at 48. The link 46 is pivotally connected with the breech bolt at 49 and the link 41 is pivotally connected with the slide at 50. When the slide 21 is in its rear position as shown in Fig. 3, the two links 41 and 48 are held substantially in alignment in the relative positions shown. A lug 41a on the link 41 engages the link 46 to prevent downward movement beyond the position shown.

When the slide 21 moves forward under the inuence of the action spring 32 the two links 46 and 41 and the breech bolt 45 move in unison with it until the breech bolt nearly reaches its forward position, the link 46 being then approximately in register with the opening Id in the top wall of the casing. At or about the time that the link comes into register with the opening the curved portion 46h of the link 46 engages two cams 5I projecting inward from the respective side walls lb, lb of the casing. In the drawings only the cam on the left hand side is clearly shown, but it will be understood that there is av similar cam on the right hand side. These cams 5I cooperate with the curved portion 46b of the link 46 to force the link upward into the opening Id, the rear end portion of the link abutting against the rear wall of the opening as clearly shown in Fig. 2. In the meantime the slide 21 has continued its forward movement, thus bringing the link 41 into a substantially upright position. With the parts in the position shown and described, the breech bolt is firmly locked in its forward or breeched position and is well adapted to resist the recoil action incident to firing. Following ring the slide 21 is moved rearward by the action of the gases of explosion in the manner already described, the link 41 serving first to draw the link 46 downward out of locking position and then to move the link 46 and also the bolt 45 rearward to the positions shown in Fig. 3.

Reference has already been made to the fact that the slide 21 can be removed through the rear of the casing. It will be understood that the breech bolt 45 and the links 46 and 41 are similarly removable, all of these parts being removable as a unit.

A firearm incorporating the present invention is intended to be used with cartridges having annular grooves in the heads thereof, and the front end of the breech bolt is provided with vertical ribs 52, 53 which cooperate to form a vertical vgroove for receiving and retaining the heads of the cartridges. When the breech bolt is in its forward position asshown in Fig. 2 the head of the cartridge which is in central position in the feed channel 31 is vertically below the groove in the front of the breech bolt. For withdrawing the cartridge from the feed channel and lifting it into proper relationship to the breech bolt there is provided an extractor 54. This extractor is provided with a pivot pin 55 which fits a transverse pivot opening in the breech bolt, the extractor thus moving bodily rearward and forward as the breech bolt moves. The extractor 54 is provided with a transversely extending tooth 56 which is so shaped and positioned as to enter the groove in the cartridge when the breech bolt and the extractor are in their forward positions as shown in Fig. 2.

A suitable cam mechanism is provided for con.- trolling and guiding the relative movements of the extractor, but as this cam mechanism constitutes no part of the present invention and is fully disclosed in my said application No. 719,862, itis not necessary to include a detailed description of it in this present specification. It is sufficient to say that when the breech bolt moves rearward the extractor moves rearward and upward, causing the cartridge to be extracted and then lifted into alignment with the chamber in the barrel. As the breech bolt returns in the forward direction, the cartridge is inserted into the chamber and the extractor is again moved downward into position to engage another cartridge in the feed channel.

A second extractor 69 is provided for extracting the empty shell from the chamber as the breech bolt moves rearward. This extractor serves in cooperation with the ejector to eject the empty shell from the ejection opening 16 in the right wall of the casing.

Mounted in a hole in the breech bolt 45 is a firing pin 18 capable of limited longitudinal movement and having an enlarged head 18a at the rear. The firing pin is provided with a lug 19 which projects upward through a suitable slot in the breech bolt and when the parts are in their rearward positions, as shown in Fig. 3, the lug 19 projects into an opening 8U in the link 46.`

The forward edge of the opening 88 is curved and serves as a cam surface to engage the lug 19 and thus move the firing pin 18 relatively rearward during rearward movement of the breech bolt. The lug 19 serves to positively prevent the firing pin from coming into engagement with the cartridge except when the breech bolt is in its forward position, as shown in Fig. 2.

For actuating the firing pin 18 there is provided a hammer 8l pivoted at 82 in a recess in the top plate 4. Fig. 3 shows the hammer in cocked position, it being so held by a sear 83 pivoted to the plate 4 at 84 and engaging a shoulder Sia extending transversely of the hammer. The sear 83 is biased toward its engaged position by a spring pressed plunger 85. The hammer is biased toward its firing position by means of a link 86 pivoted to the hammer at 81. The link is supported and guided at the rear by a lug 88 through which it extends. A spring 89 surrounds the link and-abuts against the lug `88. The forward end of the spring abuts against a shoulder on the link.

vlThe-hammer is cocked by engagement with the slide 21 vand -its associated parts as they move rearward from the'po-sition shown in Fig. 2 to the position shownin Fig. 3. To facilitate cocking the slide 21 is provided with two upward projecting lugs 93, 90 Vwhich initially engage the hammer to start the cocking movement thereof. Subsequently the hammer is engaged by the upward extension 46a on the link 46 which serves to-1nove it to its fully cocked position, as shown in Fig. 3.

vIn order that the hammer, when released, may actuate the firing pin there is provided an intermediate striker 9| carried by the link 41. This `striker is in the form of a rod slidably mounted in a hole in the link and having longitudinal movement therein, such movement being limited by a pin 92 extending transversely of the link and extending through a notch in the rod or striker. vThe relationship of the parts is such that when the breech bolt is in its forward position the strikerV 97| is in engagement with the enlarged rear end portion 'I8a of the firing pin 18. When the hammer is released in the manner to be presently described it moves from the position shown in Fig. 3 to the position shown in Fig. 2, engaging the striker and driving it forward to actuate the `firing pin and to thus cause the cartridge to be fired.

The lower right hand portion of the sear 83 is cut away'to provide a notch for a Sear operating lever 93 as shown in Fig. 9. This lever is clearly shown in Fig. 2, but a part of it is omitted from Fig?, in order that the sear itself may be more clearly shown. The operating lever 93 is pref- 'erably pivoted coaxially with the hammer 8| and 'the forward end thereof is in engagement with .the downward facing top wall of the beforementioned notch in the Sear. The tail portion 93a of the lever is adapted to engage the top wall of the casing, as shown in Fig. 3, so as to limit movement in the clockwise direction. For actuating the lever93 and for thus in turn actufating the sear 83 there is provided an upward `projection 94 at the rear of the slide 21 and at the right `hand side thereof, as. shown in Figs. 2, 3, 5 and 6. When the parts reach their forward positions as shown in Figs. 2, 5 and 6, the extension 94 on the slide 21 is forced underneath the forward portion of the lever 93, thus forcing the said forward portion upward and moving the sear 83 in the counter-clockwise direction so as to 'release the hammer.

For holding the slide 21 in its rear position as shown in Fig. 3 there is provided a second sear 95 pivoted to the bottom plate 5. This Sear is spring pressed upward and engages a notch 96 in the bottom of the slide. Carried by the rear jplate 1 is a manually operable trigger 91 having a -tail portion which projects forward through an opening in the plate and is adapted to engage the sear 95. A spring pressed plunger 98 tends to hold the trigger in its rearward inoperative position.

In initially loading the gun in order to start -flring itis ordinarily necessary to operate the mechanism of the gun by hand in order to withdraw the rst cartridge from the belt and transfer it into the position shown in Fig. 3. For this purpose there is provided a handle S9 extending through a slot |30 in the right side wall of the casing and fitting a hole in the slide 21. The

3 slot |00 is enlarged at its-rear end and the handle 99 is so formed that it can vbe removedonly when in register with the enlarged rear end of the slot.

When the trigger 91 is pressed forward the sear 95 is disengaged from the slide'21 and the slide moves forward, causing the links 46 and '41 and the breech bolt 45 to assume the positions shown in Fig. 2. When these positions are reached the projection 94 on the slide 21 releases the hammer 8| in the manner already described, thus actuating the firing pin and causing firing. Thereupon the vgases of explosion enter the cylinder 3| and drive the piston 29 rearward, thus moving the slide .21 rearward and causing the various parts of the gun to assume the relative positions shown in Fig. 3. During this rearward movement a new cartridge is extracted from the belt and the shell of the exploded cartridge is ejected in the manner already described. If, in the meantime, the trigger 91 has been released and permitted to resume its normal position, the slide is caught and held by the Sear 95 and no further firing takes place. If, however, the trigger 91 is held in its forward ring position the parts immediately again move forward to the ring position shown in Fig. 2 and firing again occurs. Thus volley firing may be continued so long as the trigger 91 is held and so long as the supply of cartridges in the belt is not exhausted.

In addition to the parts already described the gun may also be provided with a means for retarding the ratefof hre. This means may be included or omitted as desired.

As shown, particularly in Figs. 8, 10 and 11, there is provided an auxiliary sear |02 mounted coaxially with the sear 33 and biased toward its engaged position by a spring |03. The sear |02 is positioned at the left side of the gun and is adapted to engage the same shoulder 8|a in the hammer that is engaged by the sear 83. For disengaging the Sear |02 from the shoulder 8|SL there is provided a slide or sear release |04 at the left side of the gun, this slide being guided in part by the pivot pin at 82 and in part by a pin y| projecting inward from the left side of the recess in the top plate 4. When the slide |04 is in its rearward position as shown in Fig. 11 the sear |02 engages the shoulder 3|a and prevents Vmovement of the hammer even though the sear 83 be released in the manner heretofore described. If the slide |04 be moved forward to theposition shown inFig. an extension |04ab on the slide engages the sear to disengage it and thus release the hammer.

":ecured to the top plate A4 is a bracket |06, shown in Figs. 2, 3, 5, 6 and 7, this bracket being U-shaped and carrying two pivot pins |06a and |01. Mounted on the pivot pin |06a is a ratchet wheel |08 and an escapement wheel |09, these two wheels being connected together for movement in unison. Mounted on the pivot p-in |01 is an escapement weightl I0 having teeth thereon which engage the teeth-on the wheel |09. The teeth on the escapement weight are so related to the teeth on the wheel that the weight is forced -to oscillate as the wh-eel is turned. Thus thel weight offers resistance to the turning of the wheel.

Pivotally mounted at I I is a lever I |-2 which is biased for movement in the counter-clockwise direction by means of a lspring I I3. Pivotally connected at i I4 to the lever I I2 is a ratchet arm I I5 having teeth thereon adaptedto engage with the teeth of the ratchet wheel IIGS. A spring I6 serves to bias the arm I i5 in the clockwise direction, thus tending to hold it in engagement with75 the wheel. The lever II 2 is positioned at the left side of the casing and is adapted to be engaged and reset by a cam surface II'I on the slide 2l. Thus when the slide moves rearward the lever H2 is moved or reset in the clockwise direction to the position shown in Figs. 2 and 1. In so moving the teeth on the arm H may snap over the teeth on the wheel |08 without causing the wheel to rotate.

It will be seen that the lever H2 after having been moved by the cam I I'I to the position shown in Fig. '7, tends to move in the counter-clockwise direction, but it can so move only by causing corresponding rotation of the ratchet wheel I 08. The ratchet wheel is restrained from rapid movement by reason of its connection with the escapement wheel I E39. Thus the lever H2 is permitted to move in the counter-clockwise direction, but only at a relatively slow rate determined by the action of the escapement weight H0.

The lever H2 is provided with a forward eX- tension I I2gv which is adapted to engage the rear edge of the slide H34. Thus as the lever moves relatively slowly in the counter-clockwise direction, the extension H2a engages the slide IM so that the slide is moved forward to release the sear IllZ. Fig. 11 shows the extension H2a just coming into engagement with the slide, the slide, however, not yet having been moved.

From the foregoing description it will be apparent that when the main operating slide 21 moves rearward to the position shown in Figs. 3 and 7, the lever H2 is moved in the clockwise direction, to the position shown in the same gures. If the trigger 91 is maintained in its depressed position the slide 2'I with its associated parts immediately moves forward to the position shown in Figs. 2, 3 and 6, thus releasing the main sear 83 in the manner already described. Firing, however, does not immediately occur for the reason that the hammer is still held by the auxiliary sear I2. However, as soon as the cam surface II'I on the slide 21 moves out of the way of the lever H2 the said lever starts to move relatively slowly in the counter-clockwise direction, the extension H2a thereof eventually engaging the slide IEM as shown in Figs. 5 and 11. The slide IM is then pushed forward to release the sear H32 and thus permits the hammer to move and cause firing as shown in Fig. 6. With this retarding mechanism in use the rate of re may be very much less than it otherwise would be, the amount of decrease in the rate being in large measure dependent upon the size of the escapement weight I I.

It will be observed that when the retarding mechanism is used the main sear 33 normally has no control of the firing, but the said sear nevertheless serves as a safety means to prevent premature release of the hammer in the event of any jamming or malfunctioning of the gun. The sear 83 prevents release of the hammer before the breech bolt reaches its forward locked position.

The retarding mechanism serves not only to decrease the rate of fire but also to increase accuracy. The momentary delay between the closing of the breech and the firing of the cartridge permits vibrations to expend themselves so that the gun is in a static condition at the instant of firing.

In order that the retarding mechanism may be rendered inoperative when not required, there is preferably provided a transverse shaft or pin H8 adapted to be oscillated by means of a lever I I9 on the exterior of the casing. Secured to the pin H8 is a linger or projection |20 which is projectable into the arc of movement of the lever I I2, as shown in Fig. l0, to positively maintain it in its rearward or inoperative position. Associated with the finger 20 is a projection I2I which engages an extension IMb on the slide |04 to hold the slide in its forward position and to thus hold the sear |92 in its inoperative position, as also shown in Fig. l0. With the parts in this position the retarding mechanism is entirely inoperative and the action of the gun is exactly the same as it would be if the said mechanism were not provided.

By moving the lever H9 in the counter-clockwise direction the finger I2!) and the projection i2I can be moved to the positions shown in Fig. ll, thus freeing the retarding mechanism and permitting it to operate in the manner which has already been fully described.

What I claim is:

l. An automatic firearm comprising in combination, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing, an operating slide automatically and rectilinearly movable rearward upon firing and biased for automatic return movement to its forward position, pivoted link mechanism connecting the breech bolt with the.` slide and enabling the latter to move the former, automatic means associated with the bolt and serving during rearward and forward movements thereof to feed cartridges successively to the chamber of the barrel, a firing pin carried by the bolt and movable longitudinally relatively thereto, a hammer pivoted to the casing and serving when released to actuate the liring pin, a scar for holding and releasing the hammer, means for cooking the hammer during rearward movement of the slide, and an upward projection on the slide for moving the sear to release the hammer when the slide reaches its forward position.

2. An automatic firearm comprising in comblnation, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing, an operating slide automatically and rectilinearly movable rearward upon firing and biased for automatic return movement to its forward position, pivoted link mechanism connecting the breech bolt with the slide and enabling the latter to move the former, automatic means associated with the bolt and serving during rearward and forward movements thereof to feed cartridges successively to the chamber of the barrel, a firing pin carried by the bolt and movable longitudinally relatively thereto, means on the firing pin engageablc by the pivoted link mechanism for retracting the firing pin relative to the bolt, a hammer pivoted to the casing and serving when released to actuate the firing pin, a sear for holding and releasing the hammer, means for cooking the hammer during rearward movement of the slide, and means on the slide for moving the sear to release the hammer when the slide reaches its forward position.

3. An automatic firearm comprising in combination, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing, an operating slide automatically movable rearward upon firing and then automatically returning to its forward position, link mechanism connecting the breech bolt with the slide and enabling the latter to move they former, automatic means associated with the bolt and serving during rearward and forward movements thereof to feed cartridges successively to the chamber ofl the barrel, a ring pin carried by the boltand movable longitudinally relatively thereto, a hammer pivoted to the casing, a sear for holding and releasing the hammer, and a striker carried by the link mechanism and interposed between the hammer and the ring pin when the bolt is in its forward position, the said striker thus enabling the -hammer when released to actuate the firing pin.

4. An automatic firearm comprising in combination, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing, a longitudinally movable operating slide adjacent the bolt which upon iiring automatically moves rearward to a greater extent than the bolt, two connected operating links pivotally connected respectively with the bolt and with the slide, the bolt connected link when the bolt and slide are in forward positions serving to lock the bolt and the slide connected link upon rearward movement of the slide serving to eect unlocking and then to move the other link and the bolt rearward, automatic means associated with the bolt and serving during rearward and forward movements thereof to feed cartridges successively to ,the chamber of the barrel, a firing pin carried by the bolt and movable longitudinally relatively thereto, a hammer pivoted to the casing, a sear for holding and releasing the hammer, and a striker carried by the slide connected link and interposed ybetween the hammer and the firing pin when the bolt is in its forward position, the said striker thus enabling the hammer when released to actuate the firing pin.

5. In an automatic rearm, the combination of a breech casing, firing means, sear mechanism for holding the firing means in non-firing position, actuating means for moving the sear mechanism to inoperative position, means for positively preventing said actuating means from moving the sear mechanism, and a second means for moving the sear mechanism to inoperative position and for holding the same in said position.

6. In an automatic firearm, the combination of a breech casing, a sear, a sear release movable to a sear releasing position, means to move the sear release to releasing position, means for preventing the i'lrst means from moving the sear release, and a second means for moving the sear release to releasing position and for holding the same in said position.

7. In an automatic rearm, the combination of a breech casing, a sear, a Sear release movable to a sear releasingv position, a lever pivoted to the casing and engageable with the sear release to move the same to releasing position, means mounted on the casing projectable into the arc of movement of the lever for preventing engagement of the same with the sear release, and means for moving the Sear release to releasing position and for holding the same in said position.

8. In an automatic rearm, the combination of a breech casing, a sear, a Sear release movable to a sear releasing position, a lever pivoted to the casing and having a projection thereon for engagement with the sear release to move the same` to releasing position, and means pivotally mounted on the casing having two projections thereon, one for engagement with the projection on the lever for preventing engagement of the latter with the sear release and the other for engagement with the sear release to slide the same to releasing position and for holding the same in said position.

9. In an automatic rearm, the combination of a breech casing, a sear, a scar release. movable to a sear releasing position, means to move the sear release to releasing position, means for controlling the rate of re connected with said rlrst named means to move the same to cause the sear release to be moved to releasing position, means for preventing the iirst means from moving the sear release, and a second means for moving the sear release to releasing position and for holding the same in said position.

10. In combinationin-an automatic firearm, a barrel, a breech casingcarrying the barrel, a longitudinally movable breech bolt in the casing, a longitudinally movable operating slide adjacent the bolt which upon ring automatically moves rearward to a greater extent than the bolt, two' connected operating links pivotally connected respectively with the bolt and with the slide, the bolt connected link when the bolt and slide are inforward positions serving to lock the bolt and the-slide connected link upon rearward movement of the slide serving to effect unlocking and then to move the other link and the bolt rearward, a ring pin on the bolt longitudinally movable relatively thereto, a hammer pivoted to the casing and serving when released to actuate the iiring pin, a sear for holding the hammer, means for cooking the hammer during rearward movement ofthe slide,

means for moving the sear to release the hammer after a predetermined interval of time following the movement of the bolt to its forward position, and means dependent on the rearward movement ofthe slide for resetting the sear moving means.

11A.A In combination in an automatic firearm, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing automatically movable rearward upon firing and biased for automatic return movement to its forward position, a ring pin carried by the bolt and movable longitudinally relatively thereto, a hammer pivoted to the casing and serving when released to actuate the ring pin, a sear for holding the hammer, means for cooking the hammer during rearward movement of the bolt, a longitudinally movable slide for moving the sear to release the hammer, and spring means for automatically moving the slide in the sear releasing direction to release the sear after a predetermined interval of time following the movement of the bolt to its forward position.

12. In combination in an automatic firearm, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing automatically movable rearward upon firing and biased for automatic return movement to its forward position, automatic means associated with the bolt and serving during rearward and forward movements thereof to feed cartridges successively to the chamber of the barrel, a firing pin carried by the bolt and movable longitudinally relatively thereto, a hammer pivoted to the casing and serving when released to actuate the ring pin, a scar for holding the hammer, means for cooking the hammer during rearward movement of the bolt, a longitudinally movable slide for moving the sear to release the hammer, means for moving the slide in the sear releasing direction to release the sear after a predetermined interval of time following the movement of the bolt to its forward position, and a single manually operable means for holding the slide moving means in an inoperative position and for holding the slide in the position corresponding to the releasing position of the sear.

13. In combination in an automatic rearm, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing automatically movable rearward upon ring and biased for automatic return movement to its for- Ward position, a firing pin carried by the bolt and movable longitudinally relatively thereto, a hammer pivoted to the casing and serving when released to actuate the ring pin, a main sear for holding the hammer, an auxiliary sear for also holding the hammer, means for cooking the hammer during rearward movement of the bolt, means for moving the main sear to its hammer releasing position, which means acts immediately upon the movement of the bolt to its forward position, and means for normally moving the auxiliary sear to its hammer releasing position after a predetermined interval following the movement of the bolt to its forward position.

14. In combination in an automatic firearm, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing, a longitudinally movable operating slide adjacent the bolt which upon ring automatically moves rearward to a greater extent than the bolt, two connected operating links pivotally connected respectively with the bolt and with the slide, the bolt connected link when the bolt and slide are in forward positions serving to lock the bolt and the slide connected link upon rearward movement of the slide serving to eiect unlocking and then to move the other link and the bolt rearward, a ir' ing pin on the bolt longitudinally movable relatively thereto, a hammer pivoted to the casing and serving when released to actuate the firing pin, a main sear for holding the hammer, an auxiliary sear for also holding the hammer, means for cocking the hammer during rearward movement of the bolt, means for moving the main sear to its hammer releasing position, which means acts immediately upon the movement of the bolt to its for- Ward position, means for normally moving the auxiliary sear to its hammer releasing position after a predetermined interval following the movement of the bolt to its forward position, and means on the operating slide and acting during rearward movement thereof for resetting the means for moving the auxiliary sear.

15. In combination in an automatic firearm, a barrel, a breech casing carrying the barrel, a longitudinally movable breech bolt in the casing automatically movable rearward upon ring and biased for automatic return movement to its forward position, a ring pin carried by the bolt and movable longitudinally relatively theretoa hammer pivoted to the casing and serving when released to actuate the rng pin, a main sear for holding the hammer, an auxiliary sear for also holding the hammer, means for cooking the hammer during rearward movement of the bolt, means for moving the main sear to its hammer releasing position, which means acts immediately upon the movement of the bolt to its forward position, means for normally moving the auxiliary sear to its hammer releasing position after a predetermined interval following the movement of the bolt to its forward position, and means for moving the auxiliary sear to an inoperative position and for holding the same in said position.

MARRINER A. BROWN'ING.