US Patent 7464548 Shape memory alloy linear actuator

Linear actuators including coupled elongate members formed of shape memory alloys are provided. Members that lengthen when heated are coupled to members that shorten when heated such that stroke amplification gains are derived from each member. The members may be tubular and may be coaxially arranged for telescopic extension and collapse. Sections of a modular structure such as a space vehicle may be latched and clamped together for assembly or for docking by utilizing linear actuators having shape memory alloys that are actuated thermally.