GB135383A - - Google Patents

Abstract

135,383. Craig, A. M. Feb. 5, 1919. Machine guns.-Consists (1) in adapting the breech-bolt to be locked in its forward position by the engagement of cushioned rotary members, slidable transversely in the breech-casing, with sockets in the bolt; (2) in adapting these members to be unlocked from the bolt by the recoil of the firing-pin; and (3) of means for controlling the relative movements of the breech-bolt and firing- pin. In the form shown in Fig. 1, the breech-bolt 13 is of square section at its rear end 14, in which are formed sockets 18 designed to receive spring- pressed balls 19, Fig. 5, housed in transverse guideways 19<a> in the breech-casing 15; these balls serve to lock the bolt in its forward position. The firing-pin 27, Fig. 3, has an enlarged portion formed with a conical surface, 34, which serves to force the balls 19 out of their sockets 18 and so unlock the bolt on the initial recoil of the firing- pin after discharge. The firing-pin extends rearwardly through am extension 22 of the bolt, and carries a collar 41 adapted to slide in a member 23, itself adapted to slide in the bolt-extension 22, and forming one abutment of springs 25, 26 which engage respectively at their other ends a shoulder 25<a> on the firing-pin, and the front wall of the extension 22. A pin 39 on the member 23, Fig. 10, is adapted to slide in a slot 36 formed in the bolt-extension 22; while a pin 40 on the firing-pin is adapted to slide in a slot 42 formed in the member 23. The firing-pin is adapted to be locked temporarily to the breech-bolt during part of its movement by the engagement of latches 29, Fig. 7, housed in a slot 28 in the firing-pin, with the sockets 18, the ends of the latches being pressed apart by a spring 31 weaker than the springs 21. When the bolt reaches its forward position under the action of spring 12a, the balls 19 enter the sockets 18, thereby forcing inwards the latches 29 and releasing the firing-pin which is then impelled forwards by the spring 25, and fires the cartridge. Simultaneously the pin 40 strikes a cam 43 in the slot 42, thereby rotating the member 23 and causing the pin 39 on the member 23 to be disengaged from the shoulder 38 in the slot 36; whereafter the springs 25, 26 throw back the firing-pin and the member 23. The firing-pin unlocks the bolt, and itself becomes locked to the bolt as already described, so that the two move rearwardly together. When the member 23 is arrested by the rear cap 12 of the breech-casing, the springs 25, 26 are stressed by the continued rearward movement of the bolt and firing-pin, and the pin 39, moving forward in the slot 36, strikes a cam 37, and is deflected behind the shoulder 38, thus locking the member 23 to the bolt extension 22. The bolt is then moved forwards by the spring 12<a> to the firing position.