GB594120A - Improvements in control systems especially for aircraft - Google Patents

Abstract

594,120. Fluid-pressure servomotorcontrol systems. SPERRY GYROSCOPE CO., Inc. Sept. 7, 1942, No. 12615. Convention date, Sept. 5, 1941. [Class 135] A control system, particularly for automatic pilots on aircraft, including a relay valve actuated by a member subject to a controlling pressure has additional means for actuating the relay valve by a delayed pressure derived from the controlling pressure. Fig. 1 shows the invention applied to a system for controlling a rudder 89 by a directional gyroscope 1. The rudder is operated by a double-acting power piston 87 controlled by a relay valve 45 comprising a piston valve with three lands 69, 71 and 73 adapted to control the connection of the pipes 81, 83 leading to the power cylinder with a pressure supply pipe 63 and exhaust pipe 65. The outer faces of the lands 69, 73 are subject to the pressures in the pipes 81, 83 and the valve spindle 75 is coupled to three diaphragms 91, 93, 99. The chambers of the diaphragms 91, 93 are connected by pipes 43, 41 to chambers 35, 33 connected by ports 29, 30, 31, 32 in an adjustable seat member 27 with a chamber 25. A control valve housed in the chamber 25 comprising opposed and staggered semi-cylindrical blocks 21, 23, Fig. 2, is connected by its spindle 17 with the vertical outer gimbal ring of the gyroscope 1. This ring carries a compass card 13 visible through a window 15. The lower part of the chamber is connected through a passage 49 with the gyroscope casing which is exhausted through a conduit 51. The upper part of the chamber, 25 is connected to atmosphere by a pipe 47. Normally, equal pressures are maintained in the pipes 41, 43, but when relative movement between the control valve and its seating takes place a differential pressure is produced in the pipes 41, 43 causing a movement of the relay valve and resultant rudder movement. The chambers on each side of the diaphragm 99 are connected to the pipes 41, 43 through pipes 101, 103 filled with adjustable throttles 105, 107, the pipes being joined by a pipe fitted with an adjustable throttle 111. The pressure differentials on the pipes 41, 43 are thus slowly permitted to act on the diaphragm 99 which is smaller than the diaphragm 91, 93 in a direction to oppose the differential acting on the dia. phragms 91, 93. Specifications 531,388 and 531,391 are referred to.