Patent ID: 11927181

Abstract:
An SMA actuation apparatus (1) comprises a support structure (2) and a movable element (3) supported thereon by a suspension system (8, 10) that supports the movable element on the support structure and guides movement of the movable element along a movement axis. Two closely spaced lengths of SMA wire (4) that are close to parallel and inclined at the same acute angle with respect to a plane normal to the movement axis are connected to the support structure and to the movable element so as to apply respective forces to the movable element with respective components parallel to the movement axis that are in opposite directions. The two lengths of shape memory alloy wire apply a couple to the movable element perpendicular to the movement axis and the suspension system includes a pair of flexures or bearings that resist the resultant couple applied to the movable element by the lengths of SMA wire.