Patent GB-274650-A (GB)
Title: Improvements in or relating to automatic firearms
IPC: F41A19/47
Filed: 1926-07-30
Abstract: 274,650. Oberhammer, L. July 30, 1926. Breech actions. sliding breech-block.- An automatic piston in which the striker can be cocked and released for firing the first shot by a pull on the trigger, is constructed so that when the breech is opened and closed by hand to load the pistol, the striker remains uncocked. Preferably also if the striker has already been cocked, it is automatically uncocked when the breech is opened by hand. As shown in Figs. 1 and 2, the firing mechanism comprises a pivoted hammer 5 turning on a cross pin 19 and having a side projection 10, a sear 12 pivoted on a cross-pin 13 and having a side projection 14 and a hooked forward part 15, and a sear-operating link 6 having three arms 7 - - 9, the top arm 7, which constitutes the cocking arm, having a notch 11 adapted to engage the projection 10, the bottom arm 8 being adapted to engage the projection 14 to actuate the sear, and the middle arm 9 being adapted to engage over the cross-pin 13. The link 6 also has a notch 16 in its lower surface. In the position shown in Fig. 1, the pistol is not loaded and the notch 11 is behind the projection 10, so that a pull on the trigger produces no effect. When the breech-slide 2 is retracted by hand to load the pistol, the hammer is turned back but is not held at full cock because the sear is held inoperative by its forward hooked part 15 engaging the underside of the sear-operating link 6. When the breech-slide is returned, the hammer returns until caught by the cocking notch 11. The parts are now in the position shown in Fig. 2 in which a pull on the trigger retracts and releases the hammer and fires the first shot. When the breech opens automatically, as the trigger and link 6 are in the retracted position, the hook 15 of the sear rises into the notch 16 and the sear nose holds the hammer at full-cock. A short pull on the trigger then operates the sear by the arm 8 engaging the projection 14. Fig. 6 shows a modification in which a sliding firing pin 20 is used. The cocking link 6 is integral with a sliding trigger 4 and has a cocking projection 25 and a bottom notch adapted to be engaged by a side projection 15 on the sear 12. After the first shot the sear engages the firing pin and is actuated by a short pull of the trigger acting on a push-rod 30. In the modification shown in Fig. 8, the breech-block 31 is mounted to have a limited longitudinal movement relatively to the breech-slide. When the breech is opened by hand, the breech-block is in its forward position relatively to the slide, so that the tooth 21 of the firing pin does not engage the nose of the sear 12. When the breech opens automatically, the breech-block is in its rear position relatively to the slide and the firing pin is engaged by the sear. A similar construction having a pivoted hammer is described. In the construction shown in Fig. 12, the breech-block is integral with the slide but is prevented, during hand opening, from taking up a position sufficiently to the rear to cock the hammer, by a projection 37 on the trigger. When the trigger is pulled and the breech opens automatically, the projection 37 is depressed and the breech-block recoils sufficiently to cock the hammer. In the modification shown in Fig. 20, the sear spring 42 is in a pivoted casing 44 adapted to be turned by the link 6 when the trigger is pulled. When the trigger is in the forward position, the spring is vertical and acts in front of the sear pivot 49 so that the sear is inoperative, and does not hold the striker when the breech is opened by hand. When the trigger is pulled, the sear spring acts behind the pivot 49 and renders the sear operative.