GB1244750A - Improvements in electromagnetic actuators - Google Patents

Abstract

1,244,750. Electromagnetic actuators. RUNTAL HOLDING CO. S.A. 28 Nov., 1968 [7 Dec., 1967], No. 56407/68. Heading H1P. The working stroke of an actuator is transmitted from the armature to an hydraulically damped member by means of a spring, the armature of the actuator moving against a return spring. As shown, Fig. 1, a fixed yoke 1 carrying a coil 7 attracts an armature 2 connected to a plate 4 via a sleeve which slides along a push rod 6. The armature is biased to its unenergized position by a return spring 3 and is connected to the push rod 6 by a spring 8. When the coil is energized (ac) the armature 2 moves upwards and compresses spring 8 which exerts a force on the push rod 6 the movement of which is retarded by an hydraulic damping cylinder 9. When the coil is de-energized the armature is driven downwards by the return spring 3 and simultaneously returns the push rod by engaging collar 5. The return movement is also retarded by the damping cylinder 9. The upper end of the housing may be provided with a stop for the push rod to limit its travel. This stop may be fixed or adjustable (41), Fig. 4 (not shown), or its position may be continuously varied, Fig. 5 (not shown), or may be selectively operated (42), Fig. 4 (not shown). The damping cylinder may contain a disc valve to provide a fast return movement, Fig. 2 (not shown), and the outlets may be constructed to provide a desired response characteristic.