Patent ID: 6065934
Filing Date: 2000-05-23
Classification: F03G

Abstract:
A rotary actuator for rotating an object, the rotary actuator comprising:(a) a torque tube formed of a shape memory alloy, the torque tube having a proximal end and a distal end;(b) a super elastic return spring having a proximal end connected to the torque tube proximal end and a distal end connected to the torque tube distal end; the torque tube being longitudinally twisted relative to the super elastic return spring; and(c) a torque tube heating element positioned near the torque tube;wherein heating of the heating element causes the torque tube to enter an austenitic state in which the torque tube returns to its previous untwisted configuration; and wherein removal of heat allows the torque tube to return to a martensitic state thereby allowing the super elastic return spring to retwist the torque tube.