US2434326A

US2434326A - Mechanism for retarding the rate of fire of automatic firearms

Info

Publication number: US2434326A
Application number: US541896A
Authority: US
Inventors: John J Maciejowski
Original assignee: United Shoe Machinery Corp
Current assignee: United Shoe Machinery Corp
Priority date: 1944-06-24
Filing date: 1944-06-24
Publication date: 1948-01-13
Anticipated expiration: 1965-01-13

Description

Jar-x. 13, 1948.

J. J. MAclEJowsKl MECHANISM FOR RETARDING THE RATE OF FIRE OF AUTOMATIC FIREARMS Filed June 24, 1944 3. Shees-Sheet 1 rhwy .maw e wm ux w [A7 .WB

lilla-J1.)

N O o vNwN VEQ l,

Jan. 13, 1948.1

MECHANISMFOR RETARDING THE RATE OF FIRE OF AUTOMATIC FIREARMS .-J.v J. MAclEJowsKl .27,434,326

Filed June 24, 1944 3 Sheets-Sheet 2 Jan. 13, 1948 J J. MAclEJOwsKl MEGHANISM Foa RETARDING THE RATE:` oF FIRE oF AUTOMATIC FIREARMS Filed' June 24, 1944 3 sheets-sheet s rm ww n@ em WM 1/m. In J0 anism, is normally moved to and held in its retracted starting position by coil springs.

During the recoil movement of the ratchet rod the pawl carrier is held in its retracted starting position by said springs, a cam, which is fulcrumed on the pawl carrier and limits movement of the pawls toward each other, at such time being so positioned that the sloping backs of the teeth of the pawls are engaged by the sloping backs of the teeth of the ratchet rod during recoil movement of said rod. At the start of the counter-recoil movement of the ratchet rod driving faces of the teeth of the ratchet rod are moved into contact with oppositely disposed operating faces of the teeth of the pawls; thereby interlocking or latching the pawls for counterrecoil movement together with the rod. The pawls, which are operatively connected as above described to the piston, retard the first threequarters of an inch of movement of the ratchet rod from approximately its fully recoiled position, the retardng force being dependent upon the setting of the above-mentioned needle valve.

Just before the ratchet rod has traveled threequarters of an inch from its fully retracted position, the cam on the pawl carrier is actuated, causing the pawls to swing apart and accordingly to be disconnected from the ratchet rod, with the result that the rod is free to move forward under the propelling force of strong recoil springs operating through said breech bar to which the ratchet rod is secured. After the pawls have been disconnected from the ratchet rod, they are moved back, together with the pawl carrier, the above-mentioned yielding connections, and the piston, by the above-mentioned coil springs to their rearward retracted positions. Whilethe pawl carrier is being retracted, the pawl operating cam is rotated to a position in which it permits the sloping backs of the teeth of the pawls to be engaged by the sloping backs of the teeth of the rod, as above explained, during the next recoil movement of said rod.

It will be apparent from the foregoing that the breech bars of the gun are retarded for threequarters of an inch from approximately the start of their counter-recoil movement irrespective of the amount of recoil movement of the bars, and also that the counter-recoil movement retarding device becomes eiective before the recoiling parts of the gun have had an opportunity to build up any substantial amount of kinetic energy during their counter-recoil movement. By causing the retarding force to act on said parts for a constant distance from approximately the fully retracted position of the parts, it is possible accurately to control the cyclic rate or rate of re of the gun, even though the recoil movement varies considerably, as in the case of the Oerlikon gun. The construction and arrangement of the device and the ratchet rod are such that the ratchet rod is always released when the rod is rearward of the position it assumes when the gun is cocked, thereby insuring that the retarding movement shall never interfere with the chambering of the cartridge.

The retarding force acting on the ratchet rod through the constant distance of three-quarters of an inch may be varied by changing the size of the needle valve control opening, the rate of re of the gun being quickly and effectively reduced from its maximum of 450 shots a minute down to 50 shots a minute, for example, if desirable.

The various features of the invention will be understood and appreciated from the following detailed description read in connection with the accompanying drawings, in which Fig. 1 is a side elevation, partly broken away, of an Oerlikon gun provided with the illustrative device;

Fig. 2 is a view showing mechanism for clamping the ratchet rod of said device to a breech bar of the gun;

j Figures 3` and 4 are exploded views showing in detail the clamping means illustrated in Fig. 2;

Fig. 5 isa section on line V-V of Fig. 3; Y Fig. 6 is a section, partly broken away, on line V'I-VI .of Fig. 5;

Fig. '7 is a longitudinal vertical section showi'ng'the device for controlling the rate of re of the gun, portions of said device being retracted;

' Fig. 8 is a view showing a longitudinal vertical section, o n two dilerent planes, of said device coupled with the ratchet rod for reducing the counter-recoil speedof said rod;

Fig. 9 is a vertical longitudinal section showing the forward portion of said device about to release the ratchet rod during the counter-recoil movement of said rod;

Fig. 10 is a section on line X-X of Fig '7;

Fig. 11 is a section on line XI-XI of Fig. 10 showing the pawls of the machine swung apart by a cam for the purpose of releasing the ratchet rod;

Figs. 12 and 13 are views on lines XII-XII and XIII-XIII, respectively, of Fig. 8;

Fig. 14 is an exploded view showing in detail the construction of mechanism for retarding the counter-recoil movement of the ratchet rod;

Fig. 15 is an angular View of mechanism for rendering the cyclic rate control device inoperative; and

Fig. 16 is an enlarged view showing in detail the construction of the teeth of the ratchet rod and pawls through which the device is coupled to the ratchet rod.

The illustrative device is described as embodied in an Oerlikon 20 mm. automatic gun mounted upon a cradle 2D (Figs. 1 and 13) and having breech bars 22 (Fig. l), 24 (Figs. 1 to 6) which are arranged at opposite sides of a barrel 26 (Fig. 1), xed with relation to the cradle, and are secured through a cotter 28 to a breech block (notshown). Slidingly mounted upon flutes 30 of the barrel 26 is a barrel spring casing 32 having lateral studs 34 constructed and arranged for registration in bores 36 at the forward portions of the breech bars 22, 24, the bars being held upon the studs by spring pins 38. Surrounding the barrel are front and rear springs 40, 42 which may be considered a single spring having its forward end centered in the barrel spring casing 32 and its rear end engaging and centralized by a buffer 44. The gun, which res automatically when a trigger (not shown) is held in a retracted position, is of the full blow-back type, the breech bars 22, 24 sliding rearward upon each discharge of the gun, causing the springs 40, 42 and springs (not shown) of the buier 44 to be compressed. The cradle 20 is swiveled, for elevating the gun, upon trunnions 46 carried by a yoke 48 which is rotatable upon a pedestal (not shown) about a vertical axis for swinging the gun in azimuth.

In order to reduce the rate of fire of the gun, the recoiling parts of the gun are slowed down during the first part of their counter-recoil movement by mechanism which is hereinafter described and comprises a ratchet rod 50 secured to the breech bar 24, a check or piston 52 (Figs. 7, 8, 11, 12 and 14), and a. reciprocable carrier 54. The carrier 54 is operatively connected to the piston 52 and has mounted upon it a pair of pawls 56 which constitute a latch and at the end of the recoil movement of the ratchet rod 50 are coupled to or interlocked with said rod and are later disconnected irom the rod after the rod has moved forward approximately three-quarters of an inch from its fully recoiled position.

Formed integral with the ratchet rod 50 is a bracket 58 (Figs. l to 6) a ller piece 60 of which tsin an opening 62 (Figs. 3. 4 and 6) formed in a web 64 of the breech bar 24. The bracket 58 has initially assembled with it an angular thrust piece 66 (Figs. 2, 3, 5 and 6) a flange of which registers in a slot 68 (Figs. 3 and 6) formed in the bracket. The thrust piece 66 may be considered part of the ller piece 60 of the bracket 58 since, as will appear later, said thrust piece serves to force with clamping pressure the rear face 12 (Fig. 4) of the filler piece against the rear end of the opening 62.

The thrust piece 66 is initially secured in the slot 68 of the bracket 58 by a threaded bolt i4 (Figs. 2, 3 and 5) passing through alined openings in the bracket and the thrust piece, a nut '|6 threaded onto the bolt 14, and a screw 'I8 threaded into the bracket and having its end in engagement with the thrust piece. After the bracket 58, together with the thrust piece 66 assembled therewith, has been mounted upon the breech bar 24 with its filler piece 60 registering in the opening 62 of the web 64 of the bar, the nut 16 and the screw 'i8 are turned until a face 80 (Figs. 3 and 5) of the thrust piece 66 is forced with slight pressure against the front end of the opening 62 in the web of the breech bar, causing the rear face y 'l2 (Fig. 4) of the ller piece 66 to be forced with slight pressure against the rear end of the opening 62. During such adjustment an offset at face 82 (Figs. 2, 3 and 5) of the thrust piece 66 lies against the outer face of the web 64 of the breech bar 24.

With the bracket 58 thus mounted on the breech bar 24, a plate 84 (Figs. 2 and 4) is forced with initial pressure against the inner face 85 of the ller piece 68 of the bracket and against the inner face 86 (Fig. 4) of the breech bar by screws 88 which fit in shouldered holes 90 extending through the plate and are threaded into holes 92 in the bracket. In like manner a" plate 94 (Figs. 2 and 3) is forced with initial pressure against the inner face of the thrust piece 66 and against the inner face 96 (Fig. 2) of the web 64 of the breech bar 24 by turning screws 96 which t in shouldered holes |00 extending through the plate and are threaded into holes |02 (Fig. 3) formed in the bracket 58. The nut I6 and the screw 18 are then turned to cause the rear face 12 (Fig. 4) oi the filler piece 60 to be clamped with final pressure against the rear end of the opening 62 in the breech bar 24, insuring during such clamping action that the thrust piece 65 shall be properly arranged with its faces 80, 82 (Figs. 2 and 5) in registration with the front end of the opening 62 in the breech bar and the outside face of the web 64 of the bar. With the above construction, the ratchet rod 50, which is formed integral with the bracket 58, is positioned accurately heightwise as well as lengthwise of the breech bar 24. The screws 88, 68 are then nally set up, with the result that the plates 84, 94 secure the bracket 58 with final clamping pressure in its proper position on the breech bar 24.

Each of the pawls 56 is fulcrumed on a pin |08 secured to the pawl carrier 54 and is provided with a lateral ledge ||0 normally forced by a spring I2, opposite ends of which are fixed to studs ||4 secured to the respective pawls, against a cam ||5 secured to a fulcrum pin journaled in the carrier. During the recoil movement of the breech bars 22, 24 the ratchet rod 50 travels rearward between the pawls 56, the sloping backs H8 (Fig. 16) of teeth |20 of the rod engaging the backs I 22 of teeth 24 of the pawls and thus moving said pawls apart to permit passage of the rod between them. At the start of the counter-recoil movement of the ratchet rod 50, thrust faces |26 of the teeth |24 of the pawls 56 move into engagement with driving faces |28, of the teeth |20 of the rod, causing the piston 52, which is operatively connected to the carrier 54 through mechanism which will be described later, to be moved to the right, as viewed in Figs. 7 and 8, with the result that oil is transferred from an annular chamber |32 (Figs. 7 and 8) formed between the piston 52 and a cylindrical bore |34 in a block |36, into' each other by the cam ||6 to release the ratchet rod, which, actuated by the springs 45, 42, is returned to its forward position, shown in Fig. l.

Upon release of the ratchet rod 50 by the pawls 56, the piston 52 is returned by springs |44 (Figs. 7, 8, 13 and 14) to its initial retracted position, shown in Fig. '7, against a stop plate |45 secured by screws |48 to the block |36. Suction created in the annular chamber |32 by the retraction of the piston 52 causes oil to be sucked from the reservoir |38 to the chamber through pairs of return passaggs |50 (Figs. 8 and 13), |52 (Fig. 8) vprovided with check Valves |54. To insure against leakage of oil from the annular chamber |32, the piston 52 and the block |36 are provided with annular grooves in which t packings |56,

|58, respectively.

When the Oerlikon gun is in .a cocked position ready to start firing upon pulling the trigger (not shown), an index mark |56 (Fig. '7) on the ratchet rod 50, which mark is in approximate alinement with roots ofthe second pair of teeth of the rod,

is at the position indicated by dash line |60. Y

Although the recoil of the breech block of the gun varies considerably in accordance, for example, with the power of the charge and the elevation ofthe gun, such recoil is practically al-v aggredire `Secured to the vblock |36 by screws |62 (Figs. 7, 8 and 12) and dowels |64 (Figs. 7 vand 12) isa pawl carrier housing |66 provided with curved lateral walls |68 (Figs. 12 and 15) which are engaged by and serve as guides for the piston 52, the housing having upper and lower angular guideways |10 (Figs. 7, v8, 12 and 15) for the pawl carrier. The upper and lower portions of the housing |66 are provided with channels I 12 Vfor accommodating the pawls 56, which, when they are moved away from each other by the cam I I6 to release vthe ratchet rod 50, move into Said channels.

The block |36, 'together with the carrier housing |66, is `secured to the cradle 2'0 by 'screws '|14 (Figs. 1 and 13) which pass through vertical openingsl in the cradle and are threaded into the block and the carrier housing. -Secured to the forward end of the carrier housing |66 is a ller piece |16 provided with an opening |18 the forward portion of which lis beveled and through which the ratchet rod 50 passes.

In order that the pawls 56sha11 be interlocked with or latched to the `ratchet rod 50 approximately at the end of its recoil movement irrespec tive of the amount of such movement, it is desirable that the teeth |20, |24 of the ratchet rod and of the pawls be fairly small, considering the load which they have to carry. With a view to insuring against the teeth |20, |24 breaking, the pawl carrier 54 and the piston 52 are connected by a yieldable unit which will now be described. The pawl carrier 54 is threaded onto the forward end of a steel sleeve |82 having arecess |84 (Figs. 7 and 8) for receiving the ratchet rod 50 and having threaded onto its rear end a heavy collar |86. The rear part of the sleeve |02 is somewhat reduced in diameter and forms with an inside cylindrical face |88 (Fig. 7) of the piston 52 an annular space |30. Occupying the forward end of the space |90 and normally in 'engagement with shoulders |62 (Figs. '7 and 8), |94 of the sleeve I 82 and the pis'ton152, respectively, is a steel drive washer |96, and interposed between the drive washer andthe collar |86 are six Belleville spring washers |98.

The forward ends of the springs |44, through which the piston 52 and its associated ratchet rod retarding mechanism are moved back to their retracted positions, are secured in holes formed in 'rearward 'projections of the -collar |86, the rear ends of the springs being hooked around inwardly extending projections of a retaining plate 200 fitting in a socket of the 'stop plate |46. When the ratchet rod `50 acting .through 4the pawls 56 first moves the pawl carrier 54 under the restraining iniluence of the piston 52, the Belleville washers 198 are com-pressed slightly, as shown in Fig. y8, with a resultant cushioning action between the pawl carrier and the piston and, accordingly, a reduced -st-rain -on `the coupled-together teeth |20, |24 of the ratchet rod and 'of the pawls.

When the pawl carrier 54 is in its retracted position, shown in "Fig. `7, the pawls 56 are in their closed positions, the lateral ledges 4IIIl yof the pawls being held by the spring ||'2 in engagement'with flat faces `202 (Figs. 7, 8, 11 and 14) of the cam I I6. Secured to the fulcrum pin lI |1 'by a draw bolt or bill binder 204 (Figs. 9, v1'0, 14 and is a lever 206 through which the cam `|16 is operated to control lthe action of the pawls 56.

l"The ratchet rod 50 duri-ng the recoil lof the breech block of the .gun passes through the-'opening |18 in the filler piece |16 :and between 'the 'rod as above described, the rod entering `the recess I'84 in the sleeve |82. With the ratchet rod retarding assembly in its retracted position shown in Fig. 7, the 'recess |84 of the sleeve |82 is long enough to accommodate the maximum recoil 'of theratchet rod 50, the lines of teeth on the rod being extended sufficiently to co-operate eiectively -with the 'pawls 56 for different recoils 'o' said rod.

As above stated, when the ratchet rod 50 .starts forward from its fully recoiled position, the driving faces |28 of the 'teeth |20 of the ratchet rod move finto engagement with the faces |26 of the teeth rof the pawls, causing the pawl carrier 154 to move forward along the Yguideways |10 of 'the housing |66 and, through mechanism above rdescribed, to move the piston 52 forward. When this occurs, the oil in the .annular chamber |32 is vdischarged through a passage 208 (Fig. 7) in the block |36 and passages |42, 2| 0 in a valve housing 2I2 into the reservoir |38 in the block, the drag of the piston 52 being dependent upon the setting of the needle valve |40 in the passage |42. The needle valve housing .2I2 is constructed and arranged to t in the block |36 and is secured to the block by one or more screws 2| 4.

Just before the pawl carrier 54 has moved three-quarters of an inch from its fully retracted position, a shoulder 2I6 (Figs. 10, 14 and 15) of the lever 206 engages la stop 2 |8 (Figs. 1, 7 and 9:) fixed to the pawl carrier housing I 66, causing the lever to move clockwise, as viewed in Fig. 9, with relation to the carrier, with the result that corner portions `2.20 of the cam I I6 move into engagement with the ledges I'I0 of the pawls 56, as best shown in Fig, 11, causing the pawls to vswing apart, thereby releasing the ratchet rod 50, which then moves forward under the action of the springs 40, 42 to allow the breech block and associated mechanism to chamber and to fire the next cartridge. The pawls 56 release the ratchet rod 50 before the rear end of a slot 222 (Figs. 9, 14 and 15) formed in the lever 206 engages a pin 224 on the pawl carrier 54. At the time the ratchet rod 50 is released, a spring 226, upper and lower ends of which are secured to

studs

228, 230 on the housing |66 and the lever 206, respectively, has its axis 23| (Figs. 7, 8 and 9) spaced a considerable distance from the axis of the fulcrum pin I I1, as shown in Fig. 9. When the spring 226 is thus positioned with relation to the lever 206, it rotates said lever clockwise, as viewed in Fig. 9, with relation to the carrier 54 and overcomes the tendency of the spring I|2 acting through the ledges IIO of the cam II6 to move the lever counterclockwise. The lever 206 is rotated clockwise bythe spring .226 until the rear `end of the slot 222 engages the pin 224, the lever being temporarily held 'in .such position until the pawl carrier 54 has been moved approximately to its retracted starting position, vas will appear later.

As `soon as the ratchet rod 50 ,is released by the pawls v56, the pawl carrier 54 is moved to its .retracted position, lshown in Fig. 7, by the springs |44, suction created in the annular chamber |32 by the rearward movement 0f the piston 52 causing the oil to be sucked through the return passage |50 from the reservoir |38, .as above described.

During the retractive movement of the pawl carrier 54, the 'shoulder v216 von Vthe lever 206 engages la ystop 232 (Figs. 1, 7,9, 1'0 and 15) formed integral with an arm 264, 'best shown `in Figs. 10

f1 9 'and l5, causing the. lever-gto swing inacounter'- clockwise direction, as viewed in Fig. 7, with the result that the faces 262 of the camY H6 are brought back into registration with the lugs of the pawls 56, which, as above stated, are constantly urged toward each other jby the spring ||2. The construction Vand arrangement is such that this piston `52 engages the stop plate |46 and thus stops 'further' retractive or rearward movement of the'fpawl carrier 54, the lever 206 at such time, as shown in Fig. 7, having been rocated to a position in which theaxis 23| of the spring 226 is arranged in close proximity to the axis of the fulcrvumf pin ||'l. When the spring 226 is thus positioned, the ledges ||0 of the cam ||6 operating under the action of the spring ||2 cause the cam to be retained in its idle position inwhich-the at faces 202 of the cam are in engagement with the ledges. z

It will be apparent that immediately after the teeth |24 of the pawls 56 are moved into mashing engagementwith the ratchet rod the Belleville washers |98A are compressed, the shoulder |92 (Fig. 8l of the sleeve |82 moving slightly away from the drive washer |96 through which the piston52 is moved forward. During the continued counter-recoil movement of the ratchet rod 50 the drive washer-|96 moves into engagement with the shoulder |92 of the sleeve |82. By providing the above-described cushioning connections, the stress on the teeth |24 Yof the. pawls 56 is reduced to a minimum. ,.1`

The above-described devicemay be rendered inoperative,ito enable the gun with its trigger held back to be red at its normal rate, by causing the pawl carrier 54 to be held in its rear or retracted position with the pawls 56 locked in their open positions, the ratchet rod 5|) passing in and out of the recess |84 of the sleeve |82 without being engaged by the pawls. With this object in view, the arm 234 (Figs. and 15), provided at its upper end with the lug 232, is mounted on a fulcrum pin 236 which is carried by spaced bosses 238 on the pawl carrier housing |66. When it is desired to render the cyclic rate control device inoperative, a latch pin 246, which holds the arm 234 in its raised operative "position, is removed from registering openings in the bosses 238 and the arm. The arm 234 is then swung to its lowered inoperative position shown in dash lines (Fig. 10). With the arm 234 in its inoperative position, it will be apparent that when the open pawls 56 are retracted with the pawl carrier 54 the lever 206 will not be swung as above described to enable the pawls to extent of said movement, and mechanism for disconnecting the member from the check after said member has moved a predetermined'iixed distance from its fully recoiled position, said means comprising yieldable parts operative after said recoil-actuated member has been operatively connected to the check to insure against excessive strain on portions of said member and portions of said means which are secured together.

2. Anautomatic firearm comprising a recoiloperated reciprocating ratchet rod movable to different fully recoiled positions spaced considerable distances from each other, a check, a carrier mounted for reciprocation, a pair of pawls pivotally connected to the carrier, yieldable connections between the carrier and the check, and means for causing the pawls to be connected `to' the ratchet rod substantiallyat the end of the recoil movement of said rod and for causing the' pawls to be disengaged from the ratchet rod when'said rod hasmoved a predetermined distance from its fully recoiled position.

3. In'V an automaticA gun, .a recoil-actuated member havingra recoil movement which varies to a considerable'extent, ahydraulic check, a latch'constructed and arranged to be operatively secured to said member-substantially at the end of the recoil movement-of' said member irrespective of the extent of said movement, yield-j able connections between the latch andthe check,V

said connections being-operative to'yield afterbe moved to their closed positions, with the result that the ratchet rod 5D during its reciprocatory movement passes freely between the pawls and in and out of the recess |84 in the sleeve |82. The cyclic rate control device may be quickly rendered operative at any time by manually swinging the cam control lever 296 forward with relation to the pawl carrier 54, thereby enabling the spring ||2 to move the pawls 56 to their closed positions, and by resetting the arm 234 in its operative position shown in Fig. 14.

Having described my invention, what I claim as new and desire to secure by Letters Patent oi' the United States is:

1. An automatic rearm comprising a recoilactuated member having a recoil movement which varies to a considerable extent, a check, `means for operatively securing said member to said check approximately at the end of the recoil movement of said member irrespective of the the latch has been operatively connected to thecheck,V means for disconnecting the `v latch from the recoil-actuated'member at a iixed' predetermined stage inthe counter-recoil-movement of said member, and means for moving the latch together with said check and said connections back to retracted positions from which they are again moved by said member.

4. An automatic rearm comprising a recoiloperated reciprocating ratchet rod, a hydraulic check, a carrier mounted for reciprocation, a pair of pawls mounted upon the carrier, yieldable connections between the pawl carrier and the check, means for causing the pawls to be connected to the ratchet rod substantially at the end of its recoil movement and for causing the pawls to disengage the ratchet rod when said rod has moved a xed distance forward from its fully recoiled position, and resilient means for returning the pawl carrier, the check, and the yieldable connections back to retracted starting positions after the pawls have been released from the rod.

5. In an automatic gun, a reciprocable recoilactuated member, a. ratchet rod secured to said member, a, xed housing having a bore, a piston A:movable in said bore and forming with the bore ratchet rod during its counter-recoil movement,

means for disconnecting the pawls from the ratchet rod when said rod has moved a predetermined distance from its fully recoiled position, one or more springs for moving the piston 11 together withl thepawlabacktaa retracted: start,- ing position, and one. o): more ilyassagesl having check valves for permitting,nidetahelsucked from the resorvoir toy the chamber as, the,l piston.- is moved back toits retracted.starting,pnsition.,

6.. In an automaticy gum, a recoiL signing, a recoil-operated ratched rod-movable against the action of. saidy spring, a'. oamfierma pair of pawls which are fulorumedl on. said. carrier and are spread apart by the ratchet rod during, its recoil movement, a check piston, yieldabie connections. between the pawl; carrier and said pis.- ton, cam controlledmeans, for causing the; pawis.` to be coupled, for movement-withithe ratchet, rod substantially at theV startA oft itsy counter-recoil movement and for causing, thepawlsr toy release the ratchet rodafter it hasI moved a, predetermined distance from its fullyy recoi'led position, and springs for moving' said connections., said iz varies. considerablxt. a check., a latch,J operatively connected; toy the, check.`r resilient meansy for forcing the latch against the. teeth of said member during, the latter part, of; itsi recoil movement thereby causing. the,- latch to override said teeth during recoil1 movementfof' said member, and for causing the latchito,y become locked to. said teeth piston,A and said pawlcarrier back to their re 20 tracted positions. aftery the. pawls haveV been dis engaged from the ratchet, rod..

7. Ink an, automatiorearm., a, recoil.- actuated memberA havingI a recoil-V movement the rearward extent of which varies considerabli, ae check, ai 25 coupling constructed' and arrangedfatof connect. thel oheckto said' member; substantially atv the end ot its recoilmovement irrespective of the extent of. suchl movement and mechanismL fory disconnect-- ing the couplingt from said'. member after said an recoi-i movement the.;y nearward, extent-y off which 8,5

for counter-recoil movement therewithduring the rst, part of theeoounter-recoil, movement of said member, andmeansgor moving, the latch against the action of,l saidv resilientmeans. away. from said teeth, when said member has movedE a xed dis.- tance from therearwardextentof itsrecoil movement to, disconnect said member fromsaid check.

JOHN J. MACIEJOWSKI.

REFERENCES CITED The; following; references;v are ofi record in the le of this patent:

UNITED STATES PTENTIIS Italy. .\.-.1 Apr. 30,y 1926;