Bistable shape memory alloy inertial actuator
AssigneeSaes Getters S.P.A.
InventorsMarco Citro, Stefano Alacqua, Salvatore Coco, Giorgio Vergani
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Abstract
Bistable shape memory alloy inertial actuator capable of preventing accidental actuation caused by environmental temperature variations, its method of operation and its use in devices.
Claims15
A bistable shape memory alloy inertial actuator comprising a body connected to one or more shape memory alloy wires actuatable through a current pulse generated by an electrical circuit, said one or more shape memory alloy wires having a diameter comprised between 0.025 and 0.5 mm and being in operational contact with an inertial element movable between a first stable position and a second stable position and vice versa under the concurrent actuation of the one or more shape memory alloy wires,
- wherein said actuator is subjected to a locking force with an elastic constant K, expressed in g/mm,
- wherein the actuator has a parameter P defined as the inverse of said elastic constant multiplied by the ratio between the mass M of said inertial element, expressed in grams, and the total cross-sectional area A, expressed in mm2, of the shape memory alloy wires in operational contact with the inertial element, said parameter P=(⅟K)*(M/A) being comprised between 15 and 750 mm-1, and
- wherein said electrical circuit is configured to generate a current pulse with a duration comprised between 0.1 and 50 ms.
Dependencies are inferred from the claim text.