Shape memory alloy linear actuator
AssigneeThe Boeing Company
InventorsApolonio P. Yson, Ross H. Messinger
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Abstract
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.
Claims25
A stroke-amplifying linear actuator comprising:
- an elongate first member comprising a proximal end and a first shape memory alloy, the first member configured to shorten by a first distance when the first shape memory alloy is heated;
- and
- an elongate second member having two opposing ends and comprising a second shape memory alloy, the second member configured to lengthen by a second distance when the second shape memory alloy is heated;
- wherein the second member is coupled to the first member such that at least one end of the second member travels an amplified distance relative to the proximal end of the first member at a time when the first member is shortened by the first distance and the second member is lengthened by the second distance, the amplified distance being greater than either of the first distance and the second distance.
A stroke-amplifying thermally actuatable telescoping assembly comprising:
- an elongate tubular first member comprising a first shape memory alloy;
- and
- an elongate second member comprising a second shape memory alloy;
- the second member at least partially surrounded by the tubular first member;
- wherein either the first member and the second member are both configured to lengthen by respective distances when thermally actuated or they are both configured to shorten by respective distances when thermally actuated;
- wherein the second member is operably coupled to the first member such that a portion of the second member moves linearly relative to a portion the first member by an amplified distance at a time when the first member and the second member are both thermally actuated;
- and
- wherein the amplified distance is greater than any one said respective distance.
A stroke-amplifying thermally actuatable coaxial assembly comprising:
- an elongate first member disposed along an axis, the first member comprising a first proximal portion, a first distal portion, and a first shape memory alloy configured to forcibly change the distance between the first proximal portion and the first distal portion by a first distance when thermally actuated;
- an elongate second member disposed along the axis, the second member comprising a second proximal portion, a second distal portion, and a second shape memory alloy configured to forcibly change the distance between the second proximal portion and the second distal portion by a second distance when thermally actuated;
- and
- an intervening member disposed along the axis, the intervening member operably coupling the first distal portion to the second proximal portion such that the second proximal portion is moved forcibly along the axis by the intervening member relative to the first proximal portion when the first shape memory alloy is thermally actuated, and such that the second distal portion is moved forcibly along the axis relative to the first proximal portion by an amplified distance that is greater than the first distance and greater than the second distance at a time when the first shape memory alloy and the second shape memory alloy are both thermally actuated.
Dependencies are inferred from the claim text.