Patent GB-539808-A (GB)
Title: Improvements in hydraulic or hydro-pneumatic control devices
IPC: B64C13/00
Filed: 1940-03-21
Abstract: 539,808. Controlling aircraft. SOC. D'INVENTIONS AERONAUTIQUES ET MECANIQUES S.I.A.M. March 21, 1940, Nos. 5332 and 5333. Convention dates, April 28, 1939, and June 14, 1939. [Class 4] [Also in Group XXIX] In order to adjust the pressure side flaps of aircraft, or other parts of aircraft to certain defined positions the pivot 2 of the part to be controlled is connected by a lever to the piston of a hydraulic jack which is operated so as to receive definite step-by-step movements in either direction according as to whether the flap is to be raised or lowered. This is effected by firing a definite amount of liquid into the cylinder 6 through a pipe 40 or withdrawing the same amount therefrom under manual or pressure control. In Fig. 1, the operating member is a pusher 14 which opens a valve to supply compressed air to a cylinder 8a containing a piston 10a which is integral with a smaller piston 10 in a cylinder 9. The flap 3 is moved up or down in accordance with the setting of a switch B which can be set to open a pair of valves 27, 30 and permit another pair 28, 29 to be closed, or vice versa. As shown in Fig. 1, the valves 27, 30 are open and the piston 5 is moved to the right on operation of the piston 10a. The raising of the piston 10 causes a valve 18 to open and fluid is forced through a pipe 20 into a chamber 26, through valve 30 and into a connected chamber 25 from which it passes through pipe 36 to a tank 37. On release of the pusher 14 the spring 11 returns the pistons 10, 10a, and liquid is drawn from the port 35 of the cylinder 6 via pipe 40, chamber 23, valve 27, pipe 19 and valve 17 into the cylinder 9. The piston 5 thus moves to the right. The cylinder 6 is connected to a hydropneumatic accumulator 8 of known kind. Instead of a single control C with one pusher, a dual control can be used in which one supply of compressed air can be controlled from either of two pushers, a cut-off valve being arranged between the controls and the pipe 12. In a modification, Fig. 3, two regulating pistons Da, Db are used to control a piston 56 with rods connected at 55a, or 55b to mechanism for operating the desired flaps or the like. The pistons Da, Db are actuated by compressed fluid under control of push-buttons 60, 61. To move the piston to the right the button 61 is operated and the piston Da raised. This causes the operating fluid to close a normally open valve 66a controlling pipes 67a, 68 leading to a reservoir 67. It also causes the liquid to pass via pipe 74a, valve 73a of a valve box Fa, and pipe 75a to the left-hand end of the cylinder 57. The liquid leaves the other end of the cylinder via pipe 75b, and valve 72b of valve box Fb, this valve having been opened by a piston 77b operated by pressure in pipe 79b due to the raising of the piston Da. On release of the button 61 the piston returns under spring action and the valve 66a is opened and the cylinder 65a receives liquid from the reservoir 67 via pipes 67a, 68. By operating the button 60 the piston 57 is moved to the left in a similar manner. In a further modification the control of fluid to the cylinders of the piston Da, Db is effected by valves which are opened by pistons operated by pressing the buttons 60, 61. The buttons can then be released and the valves are only closed when one movement of the piston 56 is completed. Specification 456,863 is referred to.