US 6,981,374 B2
SMA actuator with improved temperature control
Peter E. von Behrens, Antioch, Calif. (US); and Dylan M. Fairbanks, Crockett, Calif. (US)
Assigned to Alfmeier Prazision AG, Treuchtlingen (Germany)
Filed on Feb. 21, 2002, as Appl. No. 10/80,640.
Claims priority of provisional application 60/270985, filed on Feb. 22, 2001.
Prior Publication US 2002/0113499 A1, Aug. 22, 2002
Int. Cl. F01B 29/10 (2006.01)
U.S. Cl. 60—527 36 Claims
OG exemplary drawing
 
1. A stroke-multiplying shape memory alloy (SMA) actuator comprising:
a heat sink having a first surface and a second surface, the second surface being a recess in the heat sink to increase the operating length of the SMA wire; and
at least three rigid parallel elongate members, each having a long axis and being slideable relative to one another parallel to that long axis, each connected one to another by an SMA wire such that the stroke of the actuator is substantially equal to the sum of the stroke of the SMA wires, where at least the central portion of one SMA wire of the SMA wires is in close proxmity and external to the first surface of the heat sink, and an end portion of the one SMA wire is proximate to the second surface of the heat sink and external to the recess.
wherein the rigid parallel elongate members of the actuator constitute the heat sink,
wherein a depth of the recess below the first surface is a function of at least a dimension of the one SMA wire and a surface area of the recess.