GB1023818A - Servo systems - Google Patents

Abstract

1,023,818. Fluid-pressure servomotor system. BOULTON PAUL AIRCRAFT Ltd. Feb. 16, 1965 [Feb. 17, 1964], No. 6538/64. Heading G3P. A fluid pressure servosystem comprises solenoid valve 11, 12, the fig. (not shown), the actuation of which admits fluid pressure to a chamber 15 or 16 to move a spool valve 17 from its central position to correct chambers 35, 36, at opposite sides of a piston 37, to supply and exhaust. The rod 39 of piston 37 carries an arm 40 to which is pivoted a bell-crank lever 41. Members 44, 45 at opposite ends of a cylinder 38 support an axially fixed but rotatable shaft 46 which is internally spliced to receive an externally spliced shaft 47. The end of the shaft 47 is axially fixed but rotatable in the arm 40 and a lever 48 fixed to the shaft 47 is connected by a link 50 to the end of an arm 52 of the bell-crank lever. A second lever 53, fixed to the shaft 46 is connected by a link 55 and lever 57 to a valve 58 which controls the supply and exhaust of fluid to the opposite ends of a cylinder 64 having an output piston rod 65. The rod 65 is connected to the operated member and to a lever 68 fixed to a sprocket wheel 70. A chain 71 passes round the wheel 70 and a wheel 72 and carries a pin 73 which engages a slot 74 at the end of the other arm 75 of the bell-crank lever 41. In operation, movement of the piston 37 in response to actuation of one of the solenoid valves 11 or 12 causes rotation of the bell-crank lever 41 about pin 73 to move link 50 to rotate lever 48 and hence shaft 47. Rotation of the shaft 47 rotates the outer shaft 46 and hence lever 53 to actuate the valve 58 to move the output member. Movement of the output member rotates wheel 70 to move the chain 71 and pin 73 to rotate the bell-crank lever 42 until the valve 58 is recentred. The valve 58 may be replaced by a variable-delivery pump.