Patent GB-499989-A (GB)
Title: Gun turret for aircraft
IPC: F41A27/26
Filed: 1937-10-08
Abstract: 499,989. Hydraulic apparatus; fluidactuated valves. DEWANDRE, A. Oct. 8, 1937, No. 27349. Convention date, Oct. 8, 1936. [Classes 69 (ii) and 135] [Also in Group XXI] Relates to power-operated. mountings of the " ring " type in which angular training movements of the gun itself about an axis 20 actuate air pressure distributers 38, 39 which control a pair of driving cylinders 22, 23, each containing a piston 24 or 25, the movement of which effects rotation of the turret in the desired direction. According to the invention, the pistons 24, 25 are rigid with pistons 51, 52 movable in oil cylinders 53, 54 which discharge into one another through a pipe line 55 containing a throttle valve 56 controlled by movements of the gun. Further, the throttle valve is shaped to control progressively the passage for the oil from one cylinder to the other, the passage being opened with a certain lag relatively to the opening of the fluid passages to the driving cylinders. The gun is shown supported on a U-shaped elevating arm 18 hinged at 19 to the rotary ring 16 which is connected by cables 26, 27 and pulleys 28, 29 with the pistons 24, 25 which move in a fixed cylinder block. The gun carries a projection 46, Fig. 3, which engages with play between forked parts 47, 48 of a rocker 49 on the arm 18, the rocker pressing against the distributing valves 41 that control pressure air entering at 40 and leading by ports 45 and flexible pipes to the cylinder block. The rocker 49, controlled by a spring link 69 on one side, is connected on the other side by a rod 68 to the eccentric throttle valve 59 which controls the flow of oil between the cylinders 53, 54 by way of ports leading to the pipes 55. The throttle valve is shown in Fig. 3 with a concentric portion which closes the oil passage during the period of initial opening of the air valve 41 and thereafter the eccentric portion of the throttle valve gradually increases the passage for liquid. The Specification describes an arrangement of cables and pulleys for giving large movements to the turret for small movements of the pistons 24, 25. The Specification as open to inspection under Sect. 91 also describes (a) hydro-pneumatic means controlled by elevational. movements of the gun itself for raising the U-shaped arm 18, such means forming the subject-matter of Specification 500,712 ; (b) a quick-release valve 77, Fig. 6 (Cancelled), for exhausting the air pressure in the pipes leading to the cylinder block. Air entering by a passage 82 moves a piston 76 and passes to the cylinder inlet port 83. When the pressure ceases, air can quickly escape from the cylinder by a port 81 since the spring 80 lifts the piston 76 and valve 77 ; (c) with reference to Fig. 11 (Cancelled), a double-acting form of the air pressure actuated oil pump described in Specification 500,712 for feeding the power cylinders. The air pressure cylinders 110, 110A are fed from a reservoir 133 through valves 142, 142A as described in Specification 474,870 which are automatically locked in open position by bolts 145, 145A, released by the passage of air through pipes 151, 151A when the pistons 112, 112A reach the ends of their effective strokes. The pistons being returned by springs 115, 115A thus operate alternately and maintain oil pressure in the pipes 165 leading to the power cylinders ; (d) with reference to Fig. 13 (Cancelled), means for raising and lowering the gun arch 18 by a double-acting hydraulic jack 189 fed by a pump P through valves x controlled by elevational movements of the gun. This subject-matter does not appear in the Specification as accepted.