The present invention provides a relay with a shape memory alloy (SMA) wire driven mechanism. Conventional mechanical relays rely on electromagnetic principle to operate. Hence, magnetic fields of electromagnetic relays often interfere with magnetic fields of other electrical components, thus resulting in the components physically interfering with each other. The present invention utilizes the shape memory characteristics of a SMA wire to achieve the purpose of changing the operation of the relay. Specifically, when a SMA wire is heated, it restores to its original shape or original length. Comparing to conventional mechanical relays, the relay provided by the present invention does not magnetically interfere with other electrical components, and thus is able to function effectively. In addition, because the relay of the present invention does not require iron cores or coils, available space therein is increased and may be used to accommodate control circuits with various functions.

The present invention provides a relay with a shape memory alloy (SMA) wire driven mechanism. Conventional mechanical relays rely on electromagnetic principle to operate. Hence, magnetic fields of electromagnetic relays often interfere with magnetic fields of other electrical components, thus resulting in the components physically interfering with each other. The present invention utilizes the shape memory characteristics of a SMA wire to achieve the purpose of changing the operation of the relay. Specifically, when a SMA wire is in heat, it restores to its original shape or original length. Comparing to conventional mechanical relays, the relay provided by the present invention does not magnetically interfere with other electrical components, thus is able to function effectively. In addition, because the relay of the present invention does not require iron cores or coils, available space therein is increased and may be used to accommodate control circuits with various functions.

An actuator device which includes a fixed support structure, an actuation member movable, a biasing member tending to maintain the actuation member in a rest position, a shape-memory wire connected to the structure and to the actuation member, and an electric circuit for supplying an electric current to the shape-memory wire. The circuit includes a pair of terminals. One end of the shape-memory wire is connected to a first terminal. The circuit includes further an electric switch, including a first conducting member electrically connected with the second terminal, and a second conducting member carried by the actuation member and electrically connected with the other end of the shape-memory wire. The switch is closed when the actuation member is in the rest position, and remains closed until when the actuation member reaches a working position, and opens when the actuation member passes beyond the working position.