GB1437240A - Automatic firearm having a servo-trigger mechanism - Google Patents

Abstract

1437240 Recoil controlled sear mechanisms FRANCE ARMED FORCES MINISTER OF 26 Oct 1973 [27 Oct 1972] 50052/73 Heading F3C In an open breech type automatic firearm, a pivoted sear 2, mounted in a removable casing borne by a breech casing, is operated against a spring 5 by a cam 7 borne by a longitudinally movable slider 8 against the action of a spring 10, to retain the breech in its rearward position, the cam being locked in its forward, sear actuating position, and the slider being operated by a percussion control device drawing energy from a retracting part 1 of the breech or associated mechanism, this device being selectively neutralized for burst firing, and the cam locking being selectively neutralized for retraction of the slider. A selection cam 28 is rotatable by a lever 29 to provide burst firing, single shot firing or a safety lock. In the first mode, it allows movement of the percussion control device neutralizing means in the form of a catch 17, and movement of a plate 21 fixed to a rotatable firing control shaft 6. Upon recoil of the breech mechanism part 1, a latch 13 of the control device is pivoted, but a counterlatch 11, which is spring biased with the latch 13, is held by the catch 17, thus providing no actuation of the slider 8, the sear 2 remaining retracted, as in Fig. 1. To cease firing, the shaft 6 is rotated anti-clockwise, causing a finger 20 to withdraw the catch 17, to allow movement of the latch 11, with the succeeding movement of the counter-latch 13 due to recoil, to actuate the slider 8 and thus the sear 2, to block the breech block. Here, the slider 8 is retained by a hook 22 actuated by mating surfaces R1, R2 thereof. To initiate firing, a lever 25, actuated by a catch 27 coupled to the shaft 6, engages a roller 26 coupled to the hook 22 to retract it, and thus the sear 2. For single shot firing, the selection cam 28 retains the catch 17 away from the latch 11, so that upon a single recoil, action of this latch following movement of the catch 13 and subsequent engagement with a stop 1b of the block part 1, causing rotation of the latch, causes actuation of the sear 2. For the safety mode, the plate 21 fixed to the shaft 6 is held in its Fig. 4 position to hold the catch 27 away from the lever 25, to avoid actuation thereof and thus retraction of the sear 2.