US2145136A - Recoil-operated firearm - Google Patents

Description

Jan. 24, 11939. T. F. SANDERS RECOIL-OPERATED FI REA RM Filed Nov. 2, 1937 Patented Jan. 24, 1939 UNITED STATES PATENT OFFECE RECOIL- OPERATED FIREARM Thomas Frederick Sanders, Slough, England, assignor to Sanders Small Arms Limited, London, England Application November 2, 1937, Serial No. 172,433 In Great Britain December 5, 1936 Claims. (01. 89-3) The invention relates to recoil-operated firediagrammatically the application of the invention arms and is more particularly directed to arto a sub-machine gun. To render the represenrangements for unlocking the breech bolt after tation clearer certain parts having no relation a shot has been fired and retaining the looking to the invention have been omitted, such as the.

5 mechanism in the open position until the bolt cartridge feed, which is efiected in an oblique 5 has returned to the locking position ready for the upward direction, and the firing mechanism. firing of a fresh cartridge. In the figures:

The arrangement used according to the present Figure 1 is a side elevation of the assembly in invention avoids unnecessary friction between the firing position taken in section partly on the the bolt and the locking member in this simple centre line and partly near the right hand side 10 type of mechanism and thus provides a re-loading of the gun,

mechanism suitable for sub-machine guns and Figure 2 is a corresponding view immediatedly other quick firing weapons as well as pistols, after firing a shot, rifles and light ordnance. Figure 3 is an elevation and Figure 4 an end According to the invention a recoil-operated elevation of a part of the stand, 15

gun mounted on a support to recoil longitudinally Figure 5 is a plan of the breech casing, thereon against resilient means comprises in com- Figure 6 is an elevation of the breech bolt bination a locking member movable parallel to partly in section, itself and adapted in one position to hold the Figure '7 is a plan of the locking piece,

breech bolt in place for the firing of a cartridge Figures 8 and 9 are elevation and end eleva- 20 and in another position to release the bolt and tion respectively of the same, and allow it to carry out the usual re-loading move- Figure 10 is a perspective view of the detent ments, guiding surfaces or the like between the mechanism. locking member and the recoiling parts so ar- Referring to the figures, the breech casing l is ranged that in operation the only movement of mounted on the stand 2 by means of grooves 3 5 the locking member in relation to the recoiling so as to be free to slide in a longitudinal direcparts is substantially perpendicular to the barrel, tion. The barrel is partly shown at 25 in Figures oblique guiding surfaces or the like between the l and 2. A spring 6 tends to keep the parts in looking member and the support so arranged that the position of Figure 1 or to return them to it in operation the only movement of the locking after recoil. 30 member in relation to the support is in the direc- The stand 2 is provided with two upright walls tion of the said oblique guiding surfaces or the 5 projecting into the breech casing l to cooperlike, a detent normally holding the breech casing ate in the locking arrangements as will be shown in the recoiled position, and means actuated by later. The breech bolt 5 slides back between these the bolt for releasing the detent as the bolt rewalls when unlocked to perm't a spent cartridge turns to the firing position. to be ejected and a new one to be inserted into the It has already been proposed to actuate a lockbarrel by the usual well known mechanisms. The ing member by a combination of oblique and perresidual gas causes the rearward movement of Dendicular guiding Surfaces, but the y arrangethe bolt 5. Due to this movement the recuperator 40 ments of this kind providing a Small t d a spring I is compressed and then returns the bolt 40 ex u sion f e locking me r ep n e solely e to the firing position with a new cartridge in on the locking member itself for the retention of l c In Figure 2 the bolt is unlocked and has the breech casing in the recoiled position until just tarted, its rearward movement. the bolt had returned to the firing position. The bolt, shown separately in Figure 6 has a It has also n p p to p vide a recoilstep 8 facing rearwards by which it is locked in 45 operated gun with a detent for holding the breech the firing position. The front face H] of a lockcasing back until the return of the breech bolt ing piece 9, shown separately in Figures '7, 8 and 9, to the closed position in conjunction with a abuts against the step 8 to lock the bolt in the breech bolt locking member not guided by oblique firing position. The construction of the parts by and perpendicular surfaces in the manner aforemeans of which the locking piece 9 releases the 50 said but moving transversely in relation to the bolt 6 at the appropriate time will now be debarrel and breech bolt to unlock the bolt and scribed. thereafter longitudinally with the bolt along the The locking piece 9 may be considered as havsupport. ing an elongated body it and four legs I2 pro- The accompanying drawing serves to illustrate jecting obliquely forwards and downwards. Sub- 55 stantially vertical shoulders I3 at the upper ends of the legs I2 face rearwards and abut against corresponding forward faces I 4' of the breech casing. The locking piece 9 is thus capable of bodily, substantially vertical movement only in relation to the breech casing, and when it rises high enough the front face I clears the step 8 on the breech bolt 6, allowing the latter to recede and carry out the usual reloading movements. This position is clearly shown in Figure 2 where the body of the locking piece, being in section, appears as a hatched rectangle.

The locking piece is also guided in relation to the stand and the direction of guiding is obliquely rearwards and upwards on recoil. For this purpose the four legs I2 fit accurately in 0blique slots I5 cut in the walls 5 on the top of the stand. The vertical position of the locking piece 9 is thus always determined by the relative horizontal positions of the breech casing and stand, being brought to the unlocking position at the end of the recoiling movement of the casing.

When the breech casing I has recoiled, a detent I6 pivoted at I! on the stand 2 is urged by 'a spring I8 into a notch I9 cut in the lower right hand edge of the breech casing. The breech casing and associated recoiling parts are thus held in the recoiled position by means entirely apart from the breech bolt 6 and locking member 9.

To release the recoling parts after the reloading movements have been accomplished by the bolt 6 a bell crank lever 20 is pivoted at 2I on the stand 2. This lever has one arm 22 approximately horizontal at the right hand side of the gun to bear on the under side of a tail of the detent I6 projecting forwards. The other arm 23 is roughly vertical and is on the centre line of the gun to engage a groove 24 on the under side of the bolt 6. As the bolt reaches its firing position the end of the groove 24' catches the arm 23, so that the arm 22 is raised and tips the detent I6 out of the notch I9. The spring 4 then returns the recoiling parts to their normal firing position, bringing the locking piece 9 back to the locking position ready for the next shot.

The action of the gun will now be recapitulated. On the firing of a shot the barrel and the breech casing I recoil against the spring buffer 4. During this movement the locking piece 9 rises vertically in relation to the breech casing as its legs I2 slide in the oblique slots I5 of the stand. When the front face ID of the locking piece has risen high enough to clear the step 8 on the breech bolt 6 the latter recedes and carries out the reloading movements in the usual way. Meanwhile the detent I6 holds the breech casing in the recoiled position by clicking into the notch I9.

It is only when the bolt .6 has returned to its forward position that it trips the detent I6 by means of the lever 20. The spring 4 then restores the breech casing and barrel to the firing position, and this relative movement causes the descent of the locking piece 9 in just the same way as the recoiling movement caused it to rise. The bolt is then locked and the gun is ready to fire another shot.

Obviously the various parts will be so' dimensioned in relation to the ammunition to be used that the bolt is not unlocked until the bullet has had time to reach a predetermined position in its flight.

What I claim is: r V r 1. A recoil-operated gun comprising in com- .bination a support, resilient means, a breech casing and barrel mounted on the support to recoil longitudinally against the resilient means, a breech bolt in the casing arranged to travel rearwards after firing and then forwards to re-load the gun, a locking member movable bodily into and out of a position in which it locks the bolt in the firing position, a guiding surface fast with the breech casing substantially perpendicular to the barrel, a cooperating guiding surface on the locking member in constant engagement therewith, an oblique guiding surface on the support, a cooperating oblique guiding surface on the locking member in constant engagement therewith, a detent biased to hold the breech casing in the recoiled position, and means actuated by the bolt for releasing the detent as the bolt returns to the firing position.

2. A recoil-operated gun comprising in combination a support, resilient means, a breech casing and barrel mounted on the support to recoil longitudinally against the resilient means, a breech bolt in the casing arranged to travel rearwards after firing and then forwards to reload the gun, a locking member movable bodily and having front and rear abutment surfaces substantially perpendicular to the barrel, a rearward facing surface on the bolt to engage the front abutment surface on the locking member in one position thereof and to clear it in the other position, a forward facing surface on the breech casing in constant engagement with the rear abutment surface on the locking member, an oblique guiding surface on the support, a cooperating oblique guiding surface on the locking member in constant engagement therewith, a detent biased to hold the breech casing in the recoiled position, and means actuated by the bolt for releasing the detent as the bolt returns to the firing position.

3. A recoil-operated gun comprising in combination a support, resilient means, a breech casing and barrel mounted on the support to recoil longitudinally against the resilient means, a breech bolt in the casing arranged to travel rearwards after firing and then forwards to reload the gun, a locking member movable bodily and comprising a longitudinal body with oblique legs projecting therefrom, front and rear abutment surfaces on the body of the locking member substantially perpendicular to the barrel, a rearward facing surface formed as a step on the bolt to engage the front abutment surface on the locking member in one position thereof and to clear it in the other position, at least one forward facing surface on the breech casing in constant engagement with a rear abutment surface on the locking member, two upright walls on the support one on each side of the path of the breech bolt, the walls having oblique slots to accommodate and guide the legs of the looking member, a detent biased to hold the breech casing in the recoiled position, and means actuated by the bolt for releasing the detent as the bolt returns to the firing position.

4. A recoil-operated gun comprising in combination a support, resilient means, a breech casing and barrel mounted on the support to recoil longitudinally against the resilient means, a breech bolt in the casing arranged to travel rearwards after firing and then forwards to re-load the gun; a locking member movable bodily into and out of a position in which it looks the bolt in the firing position, a guiding surface fast with the breech casing substantially perpendicular to the barrel, a cooperating guiding surface on the locking member in constant engagement therewith, an oblique guiding surface on the support, a cooperating oblique guiding surface on the locking member in constant engagement therewith, a spring-biased detent pivoted on the support and located to enter a notch in the under side of the breech casing when the latter is in the recoiled position, a tail on the detent, a bell crank lever pivoted on the support and having one arm projecting rearwards under the tail of the detent, the other arm projecting upwards, and a forward facing surface on the under side of the bolt located to engage the upward arm of the bell crank lever when the bolt has nearly returned to the firing position.

5. A recoil-operated gun comprising in combination a support, resilient means, a breech casing and barrel mounted on the support to recoil longitudinally against the resilient means, the breech casing having a notch on its under side, a breech bolt in the casing arranged to travel rearwards after firing and then forwards to reload the gun, a rearward facing abutment surface formed as a step on the top of the bolt, a forward facing abutment surface formed as the end of a groove on the under side of the bolt, a locking member movable bodily and comprising a longitudinal body with four oblique legs projecting downwards and forwards therefrom, a front abutment surface on the body of the looking member located to engage the rearward step on the bolt in one position of the locking member and to clear it in the other, rearward facing abutment surfaces projecting from the body of the locking member at the tops of the legs, forward facing abutment surfaces on the breech casing in constant engagement with the last named abutment surfaces, two upright walls on the support one on each side of the path of the breech bolt, each wall having two oblique slots to accommodate and guide two legs of the looking member, a spring biased detent pivoted on the support and located to enter the notch in the under side of the breech casing when the latter is in the recoiled position, a tail on the detent, a bell crank lever pivoted 0n the support and having one arm projecting rearwards under the tail of the detent, the other arm projecting upwards to engage the forward facing abutment surface on the under side of the bolt and located to enter into the said engagement when the bolt has nearly completed its forward travel to the firing position.

THOMAS FREDERICK SANDERS

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