GB619748A - Improvements relating to electrically operated rotary mechanisms - Google Patents

Abstract

619,748. Actuation of switches. ROTAX, Ltd., and KING, J. Jan. 8, 1947, No. 630. [Class 38 (v)] [Also in Group XXX] In a rotary actuator (see Group XXX) having a reversible electric motor driving an arm or member through a limited angular displacement by means of epicyclic gearing, a normally fixed annulus is movable under a predetermined torque to operate limit switches to stop the motor. The annulus 36 is normally held stationary by two opposing spring-loaded plungers 38 abutting a projection 37 fixed to or formed on the annulus, which also has two camlike depressions 40 formed on its periphery. Co-operating with these depressions are the plungers 41 of two normally closed limit switches having fixed contacts 44, and moving contacts 43 carried by S-shaped spring blades. When the driven member has reached the limit of its travel in either direction, it abuts a fixed stop (not shown) and the increased torque exerted by the motor on the annulus 36 causes it to turn against the action of the spring- loaded plungers 38 so permitting the plunger 41 of the appropriate limit switch to move into a depression 40 to allow the spring blade to open the switch contacts 43, 44. When the motor stops, the annulus is returned to its central position by the spring-loaded plungers 38.