GB554651A - Improvements relating to gun mountings and recoil mechanism - Google Patents

Abstract

554,651. Machine gun mountings. BOULTON PAUL AIRCRAFT, Ltd. (Soc. d'Applications des Machines-Motrices). Feb. 7, 1939, No. 4058. [Class 92 (i)] Mountings for heavy machine guns, particularly those having means as described in Specification 494,304 for reducing the amplitude of recoil when firing continuously, are provided with a hydraulic recoil and run-out brake including two valves 84, 78, Fig. 5, both of which open automatically at the beginning of recoil to provide free recoil movement the valve 84 closing at the beginning and the other 78 at the end of run out. The valve 78 is outside the amplitude of movement for continuous fire and functions only when firing ceases or single shots are fired. The gun (not shown) is supported by members 48, 18, Fig. 2, the latter being in the form of a crank with trunnions 16 and thickened webs which carry fixed cylinders 22 for pistons 40 connected by rods 42 and pins 46 with the member 48 to which the gun is connected. Liquid under pressure is admitted to each brake through a non-return valve 64 leading to a reservoir 54 and is kept under pressure by a spring-pressed piston 56. The pistons 40 which serve to compress the return springs 34 against fixed abutments 36‹ are each made hollow to form a brake cylinder and to receive a piston valve 84 having slight play on the end of its fixed rod 68, the interior of which forms a passage for liquid from the reservoir 54. During recoil, each piston 40 moves to the left and the valves 84, 78 both open to provide free passage of liquid from right to left of the piston valve 84. During run-out, each piston 40 moves to the right and the rear end of the rod 68 forms a valve seat 82 with the piston valve 84 at the beginning of run-out ; the liquid then passing through restricted openings 76. At the end of run-out when firing ceases, the member 78 on each piston 40 forms a valve by entering a space in the rear end of the rod 68.