Patent GB-143529-A (GB)
Title: Improvements in automatic multi-barrel machine guns
IPC: F41A5/18
Filed: 1920-05-17
Abstract: 143,529. Berthier, A. V. P. M. Nov. 20, 1918, [Convention date]. Machine guns; cartridge magazines.-Relates to a multi-barrel gun, especially for aircraft, having independent gas-operated breech mechanisms with a trigger and sear corresponding to each mechanism and means whereby two adjacent triggers can be operated independently or simultaneously by one hand of the operator. According to the invention, the triggers are placed so that they can be operated by the hand with which the operator grasps the controlling handle for aiming the gun. Figs. 3 and 4 show a section through one of the barrels and breech mechanisms of a four-barreled gun, and Fig. 5 is a rear end view. The barrels 56, each surrounded by a ribbed aluminium cooling jacket 32, are screwed at their rear ends into a common receiver 2, and at their muzzle .ends are crossconnected by a brace 14 having sleeves 16 fitting over each barrel and retained thereon by a single transverse locking bolt 18. Beneath each of the sleeves 16 is formed a gas-cylinder 36 connected with its barrel by a passage 40. Each cylinder contains a gas-piston 38 formed at the forward end of an actuating rod which terminates at its rear end in a striker-post 92. The actuating- rod is connected at 82 to the rear end of a tension spring 81, the forward end of which is held in a readily removable guide-block 58. The strikerpost moves in guides in the receiver 2 and protrudes through the forward part 102 of the breechbolt. The rear part 100 of the bolt, which is knuckle-jointed to the front part, has inclined grooves 142 which are engaged by projections 150 on the striker-post during its rearward movement to lower the rear portion of the bolt from behind a recess in the receiver. After unlocking, the breech-bolt is moved rearwards and retained by the engagement of a pivoted sear 96 with a projection 94. During this rearward movement the empty cartridge case is withdrawn by an extractor 130 and deflected downwards into a receptacle through an opening 98 in the actuating rod by an ejector 128. On pressing the thumb-piece 166 of the sear, the striker-post is drawn forwards by the contraction of the spring 82 and, engaging behind an abutment 144 on the bolt, carries it forwards. The bolt carries before it a fresh cartridge from a magazine 206, and when the cartridge is right home. the striker-post moving forward alone raises the rear end of the block for locking it and then fires the cartridge. The thumb-pieces 166 corresponding to each of the four sears are arranged in proximity to the handle grips 20 whereby the gun is aimed. A single thumb-piece for operating simultaneously all the sears 96 is also described. Box magazines 206 corresponding to each barrel are held by forward projections 208 and transversely sliding plates 214 engaging projections 212 at the rear. The rear end plate of the receiver is hinged at the top by pins 182 and retained at the bottom by screwed pins 194 passing through lugs 196 and provided with handles 204. Spring buffers 170 are mounted on the rear plate behind each breech-bolt. The Specification as open to inspection under Sect. 91 (3) (a) also states that the invention is applicable to automatic rifles and covers the following additional features-(1) A rotary valve 46, Fig. 6 (Cancelled), for adjusting equally the gas pressure for all the barrels for various altitudes of aircraft. The valve is hollow and has a series of helically arranged graduated holes a - - h corresponding to each gas-cylinder, and is screwed at 50 so that, when rotated by a head 52, one or other of the holes is brought into line with a venting passage 44 leading to the gas-cylinder, or the passage 44 may be sealed altogether when the valve is screwed right home. (2) A special form of knuckle-joint, as described in Specification 162,671, arranged between the sliding front portion 102 and the tilting rear part 100 of the breech-bolt. The joint, Fig. 8 (Cancelled), is formed by T-shaped arcuate ribs 112 on the front part engaging corresponding grooves in the other part. This subject-matter does not appear in the Specification as accepted.