Raychem Limited

Robert K Morgan

John R Yaeger

A shape-memory-effect actuator is provided having a shape-memory-alloy spring and a compensator spring. The alloy spring is operatively connected to a concentrically-mounted compensator spring by the use of a protective support housing which surrounds the alloy spring. The actuator includes a shape-memory-alloy spring and a compensator spring that regulates the operating conditions of the shape-memory-alloy spring to a chosen corresponding memory relaxation curve. The memory relaxation curve defines the actuator's operating stress, stroke and life.

Self-protecting and conditioning memory metal actuator

Disclosed is a shape memory effect actuator. The actuator comprises a biasing means which is normally biased in a first position and a shape memory alloy actuator element cooperatively engaged with the biasing means. The actuator element in a first unactivated condition is biased in the first position by the biasing means. In a second unactivated condition, the actuator element biases and retains the biasing means in a second position. The actuator element in an activated condition biases the biasing means in the second position. Also disclosed is a method of assembling an actuator and a cooperating apparatus and a method of operating the actuator.

Shape memory effect actuator and methods of assembling and operating

A self-regulated actuator is disclosed having a shape-memory element which is heated preferably by passing electrical current therethrough and having a reset mechanism including a circuit-breaking mechanism. The shape-memory element provides the force to retract the actuator when heated. The reset mechanism utilizes a spring-biased latch plunger that resets the actuator as soon as it has retracted a specific distance. The reset mechanism also acts as a circuit-breaking mechanism to electrically interrupt current heating the shape-memory element. The reset mechanism provides near-instant reset time and overcomes the longer wait period otherwise associated with the natural cooling of the shape-memory element. The reset mechanism prevents overheating of the shape-memory element and precludes the necessity for additional hardware to interrupt the circuit after actuation is completed. Also discussed is a self-protection means that protects the shape-memory element from deliberate and accidental overloads and to accommodate the extra motion required for high-cycle design life.

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Pleasant Hill, CA, United States of America

Robert K Morgan