Patent GB-618407-A (GB)
Title: Improvements in firing mechanism of small arms
IPC: F41A17/28
Filed: 1944-05-19
Abstract: 618,407. Small-arms. KEENE, S. I. May 19, 1944, No. 9678. [Class 119] In a firing mechanism for small-arms, the disengagement of a sear from a cocking-piece, to fire the weapon, is effected by a trigger, the movement of which is effective only when a manually-operated member has been so moved as to establish mechanical connection between the trigger and the sear when the trigger is operated, a locking device, located for operation by the hand carrying the trigger finger, being provided for rendering the manually-operated member operable or inoperable. The invention is shown in Figs. 2 and 5a, as applied to a rifle of the kind in which firing is effected by forward movement of the trigger after it has been pulled back and then released. A cocking-piece 2 has the ordinary sear notch 5 for engaging a nose 6 on a sear 7, which holds the piece 2 drawn back under the action of the usual main spring. When the nose 6 is withdrawn from the notch 5, the cocking-piece and the firing pin (not shown) are released to fire the cartridge. On pulling back the trigger 3, a bar 18 pivoted thereon engages the head 30 of a pin 29, loosely mounted in the trigger guard plate 25, so that the rear end of the bar 18 is raised. A spring-pressed finger 20, pivoted in a recess in the bar, has a projection 22 forming a shoulder 23, Fig. 5a, lying below a cam 34 which is pivoted on the sear 7. If, when the trigger is pulled back, the pin 29 is held in the position shown in Fig. 3, with its head 30 raised from a recess 31 in which it normally lies, bar 18 is tilted upwardly sufficiently for the projection 22 to snap behind the projecting end 36 of the cam 34. Then, when the trigger is released, the parts 18, 20 move forward with it, and the shoulder 23 engages and turns the cam 34, thereby moving the sear 7 about its pivot 13 so that the nose 6 is withdrawn from the notch 5 and the firing pin operates. The raising of the pin 29 into effective position is brought about by means of a pivoted arm 38 against which the pin 29 bears, the arm carrying at its rear end a plate 40 which is adapted to be gripped against the stock of the rifle. If the arm 38 is not held so as to raise the pin 29, the bar 18 slides ineffectively over the head of the pin when the trigger is pulled and released. Thus, the parts 38, 40 form parts of a safety-device, as they may be locked, to prevent the pin 29 from being raised to enable the rifle to be fired. The locking device comprises an elliptical disc 41, Fig. 5, which is pivoted in a recess in the plate 40, and coacts with a stop pin 46. The disc may be turned by the trigger finger, preparatory to firing, from the locking position shown in Fig. 5 to one in which a recess 45 in the disc is aligned with the pin 46, so that the plate 40 can then be lifted. The surface of the end of the bar 18 that engages the member 30 is so shaped, with a small flattened portion 50, that during the forward movement of the trigger, for firing, an indication is given to the operator, by sense of touch, that any further release of the trigger will result immediately in firing taking place. The application of the invention to mechanism of the usual kind, in which firing occurs when the trigger is pulled back, is also described, (Figs. 7 and 8, not shown). In this modification, the upper end of the trigger is located in a slot in the sear, on which it is pivotally mounted, and on the same pivot is a cam which bears against the top wall of the chamber housing the sear, and which also engages a stop pin. The cam is adapted to be rocked, and thus to turn the sear to release the cocking-piece, by the engagement with the cam of an arm pivoted on the trigger. This engagement can take place, when the trigger is pulled back, only if a pivoted plate (similar to the plate 40, Fig. 2, and carrying a safety locking device like the disc 41) is raised by the firing hand of the operator. The said pivoted plate is in direct contact with the arm pivoted on the trigger, an intermediate member like the part 29, 30, Fig. 2, being dispensed with.