Patent GB-191016743-A (GB)
Title: Improvements in Automatic Small Arms.
Inventor: CHEVALLIER ARNOLD LOUIS
IPC: F41A17/56
Filed: 1910-07-13
Granted: 1911-07-13
Abstract: 16,743. Chevallier, A. L., and Eastwick, J. July 13, [Cognate Application, 3121/11]. Breech actions, sliding b r c e c hblock. - Relates to automatic guns operated by an inertia weight, and especially to guns having a rotary breechblock locked and unlocked by the mechanism described in Specification 2401/10, and consists mainly in arranging the inertia weight to have a long forward movement, at least 1À3 calibres, in order to delay the opening of the breech. The invention also consists i n special firing - mechanism, safety mechanism, means for adapting for hand operation, means f o r facilitating the e loading by clips, and in a special arrangement of the recoil spring. F i g. 1 shows a gun, having the locking- mechanism de scribed in Specification 2401/10, with the parts in the firing position, except that t h e safety device is on. The rotary breech - block is not yet locked, as the firing-pin 12, which rotates the breech - block by means of studs and helical slots, is held back by the sear 19 and by two tumblers 18 pivoted to a cross-head 8 on the firing-pin 12 and bearing against an abutment 11 carried by the inertia weight 7. The firing-mechanism contains two sears. The first sear 19 is pivoted to the fixed casing, and engages the bent 21 on the cross-head 8. The second sear 22 is pivoted to the first, and has a forked end, which engages the lower end of one of the tumblers 18. The trigger acts directly on the second sear 22. If, when the gun is in the position shown in Fig. 1, the safety device 28 is drawn backwards and the trigger pulled, the sear 22 turns the tumblers 18 and depresses the sear 19, thus freeing the firing-pin. The sliding weight 7 is normally held by a spring catch 31, Fig. 1, which is depressed by a lug on the sear 22, when the trigger is pulled. Pivoted to the trigger plate is a lever 37, which falls and holds the sear 19 down out of the path of the recoiling parts when the trigger is pulled. The safety device consists of a slide 26 having two lugs 28 projecting downwards through the top of the ' cover, and, when the safety is set, as shown in Fig. 1, engaging the top of the tumblers. To take the safety off, this slide is pulled to the rear as shown in Fig. 2. The operation of the inertia weight 7 is as follows. Immediately after the discharge, the weight 7 jumps forwards, relatively, and compresses the opening springs 17, Fig. 8, as described in Specification 2401/10; during this forward movement, the lugs 28 on the safety engage the tumblers 18, and cause them to fall; the weight, while in its forward position, bears against the firing-pin and thus tends to continue the rotary locking movement of the breech-block; the weight is then thrown backwards by the recoil, and by the reaction of the springs 17 ; during this backward movement, the breech-block is unlocked as described in the above-mentioned Specification, whereupon the inertia weight and the breechblock move rearwards against the action of the return spring 45, Fig. 6, and open the breech. For hand operation, the inertia weight is prevented from moving forwards by a lever 62, Figs. 1 and 2, which is depressed into engagement with the bolt-carrier 4; the operating- handle 67, Fig. 5, is pivoted to a slide 66 fixed to the cross-head; this handle operates a cam 68, which, by pressing against the abutment 11, forces the firing-pin backwards and unlocks the bolt; when the handle is completely turned down, it engages a stud 70, which is formed on the retaining-catch 31, Fig. 1, and thus releases the inertia weight. The recoil spring 45, Fig. 6, is arranged in a detachable telescopic case 46, 53, the front part 46 of which is detachably connected to the bolt-carrier. To facilitate loading by clips, provision is made for retracting the bolt beyond the position in which it is retained bv the cartridge-lifter. For this purpose, a small section 72, Figs. 4 and 6, of the spring casing is made to rotate, whereupon a stud 77 engages a cam-surface 78 formed on the bolt-carrier. The top of the inertia weight may be formed with guides 80, Fig. 7, to aid in inserting the clip in the dark.