Shape-memory electromechanical drive
AssigneeKabushiki Kaisha Tokai Rika Denki Seisakusho
InventorMasaru Suzuki
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Abstract
A shape-memory electromechanical drive device comprising a casing, a pair of fixed terminal members carried by the casing in electrically insulated relation thereto, an actuating member supported within the casing for movement between two positions from an intermediate position in opposite directions and having a pair of spaced spring seats defined therein, and a pair of coil springs interposed between the fixed terminal members and the spring seats, respectively. Each of the coil springs is made of shape-memory alloy and capable of returning from a compressed state to an original, expanded state when heated to a predetermined temperature. These coil springs are heated by the flow of an electric current therethrough one at a time when the device is in use.
Claims5
A shape-memory electromechanical drive device for a valve or gear arrangement comprising:
- an actuating member comprising a rotor and pusher element, said rotor being rotatably supported by a pivot pin and having a pair of spring seats, said pusher element being fixed to said rotor and being operable in response to rotation of said rotor, said pusher element providing a drive force for switching said valve or gear arrangement;
- at least one pair of electrodes;
- and
- a pair of coil springs each being made of shape-memory alloy, each spring having a predetermined free length when heated and a second length when at normal temperature, said second length being less than said predetermined free length, a first one of said coil springs being disposed between one of said spring seats and a first one of said electrodes, a second one of said coil springs being disposed between another of said spring seats and a second one of said electrodes, said first electrode having an electrical current supplied thereto in a first mode, said current heating said first coil spring and causing said first coil spring to thermally expand, said second coil spring being unheated in said first mode and being compressed as said first coil spring expands, said rotor being rotated in one direction as said first coil spring thermally expands and said second coil spring compresses.
Dependencies are inferred from the claim text.