Patent GB-1356222-A (GB)
Title: Machine gun having trigger group
IPC: F41A15/14
Filed: 1972-07-26
Abstract: 1356222 A machine gun COLT INDUSTRIES OPERATING CORP 26 July 1972 [22 Nov 1971] 34927/72 Heading F3C A machine gun comprises a receiver 12, Fig. 1, an integral operating group 50, Fig. 2, mounted for operation within the receiver 12 and including a unitary bolt 52 and bolt carrier assembly 82 and a recoil buffer assembly 58, a single latch 108, Fig. 1, removably securing the operating group 50, Fig. 2, to the receiver 12 in assembled relation, the operating group 50 being removable from the receiver 12 as a single separable unit, and a trigger group 114 slidably mounted along the bottom of the receiver for cocking the bolt 52 and bolt carrier assembly 82, the trigger group 114 being movable between a forward cocking position 130, Fig. 1, and a rearward firing position where it is retained by the latch 108, the trigger group 114 in the firing position overlying and covering the latch 108 to prevent unintended unlatching. The trigger group 114 has a trigger 140, Fig. 2, mounted on a shaft 138 which is movable laterally of the receiver 12 when the trigger group is in firing position for selective locking engagement and disengagement with the receiver, the shaft 138 permitting trigger actuation only when it is disengaged from the receiver as shown in Fig. 4. In the " safety on " position the shaft 138 is received in half-moon cut-out portions 154, Fig. 4. The triggger group has a pistol grip 120, Fig. 1, by which the gun is cocked. In use pressure from barrel 10, Fig. 1, passes to a chamber 161, and moves a piston 80 so as to thrust the bolt carrier assembly 62 rearwardly during its recoil cycle. The latter strikes the recoil buffer assembly 58 and compressively loads the spring 70. If the trigger 140 is released a shoulder 128 of the bolt carrier assembly 82 moves sear 124 to condition the gun to fire the next round. If the trigger 140 has not been released, the bolt carrier assembly 82 clears the sear 124 during a forward movement and springs 90, 90, Fig. 2, drive the bolt carrier assembly 82 forwardly again to repeat the operation of chambering and firing whereby a continuous burst of fire occurs until trigger release or until there are no more rounds to be fired, whichever first occurs. In another embodiment a latch 168, Fig. 6, is pivotally supported on a housing 116B and has a thumb piece 169, Fig. 7, and a shaft 170 having flat shoulders 171, 172 thereon. The shaft 170 is received in an opening 174 of a latch 136B, the opening being shaped to allow limited freedom of angular movement of the latch and the latter being urged into a locked position by a spring 179, Fig. 5. The latch 136B is received in an opening 180, Fig. 6, in the receiver 12B and engages a wall 182 to latch a trigger group 114B in a rear firing position. A trigger 140B is pivoted on a shaft 138B which, like the shaft 138 in the first embodiment, is movable laterally to engage and disengage the receiver. In " safety on " position the shaft 138B is disposed relative to housing 116B so that a notch 188, Fig. 8, receives spring biased detent 150B, Fig. 5, to position the shaft 138B in interfering relation to sear 124B to prevent it from being moved and disengage shoulder 128B, Fig. 6, of bolt carrier 82B of bolt assembly 62A. The shaft 138B is received in half-moon cut-out portions in the receiver which are similar to the cut-out portion 154 in Fig. 4. Means are provided to ensure that manual actuation of latch lever 168, Fig. 6, will not inadvertently release the trigger group 114B when the shaft 138B is in " safety on " position, to laterally displace the shaft 138B using a thumbpiece 199, Fig. 8, to ensure against inadvertent release of the trigger group 114B, Fig. 6, and to cock the weapon.