GB685467A - Improvements in or relating to electrically-actuated mechanism for controlling fluidpressure apparatus - Google Patents

Abstract

685,467. Control of motors. BRITISH MESSIER, Ltd. Nov. 1, 1950 [Jan. 6, 1950], No. 445/50. Class 38 (iii) [Also in Group XXIX] Relates to mechanism as described in Specification 672,748 comprising fluid-pressure valve-means for controlling fluid-operated apparatus, such as a hydraulic jack, a movable selector member for actuating the valve-means, and an electric motor controlled from a distant station and serving to operate the selector member through a worm and segment of a worm gear, or through some other form of gearing, over-run of the motor after the selector member has been operated to an extreme position of its movement being allowed for by the fact that the worm and segment run out of mesh with one another at the end of the operating movement. Means are provided for spring-centring or biasing the selector member and for throwing the driving gear out of mesh so as to allow the selector member to return automatically to a pre-determined position when the gear is thrown out of mesh. As shown, the pilot motor drives the selector member 30 through a worm shaft 23 which is mounted upon a ball-race 19. A solenoid 14 is adapted to move the worm 29 into and out of mesh with the member 30 by moving the shaft 23 about the axis of the ball-race, the solenoid having an internal spring which tends to disengage the parts 29, 30, and which is overcome by the action of the solenoid, when energised, upon a push-rod 28. The solenoid may be energised simultaneously with the pilot motor or may be controlled independently. The member 30 is fixed to a cam-shaft controlling valves through which a hydraulic jack is regulated.