GB725003A - Improved fluid-pressure actuator - Google Patents

Abstract

725,003. Pneumatic single-stroke apparatus. GENERAL MOTORS CORPORATION. March 16, 1953 [March 27, 1952], No. 7135/53. Class 8 (2). [Also in Group XXIX] Locking of the fluid pressure actuated piston 3 in any position is effected by meshing of radial teeth 132 of a spring-loaded locking ring 118 carried by a rotatable shaft 100 in screwthreaded engagement with the piston 3 with corresponding teeth 134 of a collar 136 secured to the cylinder end ; unlocking being effected on the application of fluid pressure to either end of the cylinder 2 whereon the shaft 100 is free to rotate and so allows the piston 3 to be linearly displaced. In operation and to extend the piston 3 and a load device 9 linked to the piston rod 5 fluid pressure is applied to a chamber 26 through a port 126, an 'opening 160 in the collar 136 and between inner and outer races of ball bearings 102, 104 supporting the shaft 100, and fluid pressure is simultaneously applied to a lock release port 154 leading to a cylinder 142 to displace a piston 144 having an extension 148 abutting a thrust bearing 130 seated in a cup 124 secured to the spring-loaded locking ring 118. On disconnecting the fluid supply at any position of the piston 3 the ring 118 is returned by the spring 128 into engagement with the collar 136 which prevents rotation of the shaft and hence displacement of the piston 3 and its rod 5. Return of the piston 3 is effected by applying fluid pressure to a cylinder port 32 and also to the lock release port 154 ; the port 156 being connected to exhaust. Balls 29 in piston grooves 27 provide a substantially frictionless ball-nut and screw connection between the shaft 100 and the piston 3, and the ring 118 is connected to the shaft 100 by splines 108, 120 which whilst preventing relative angular displacement of the members 100, 118, allow slight axial displacement thereof.