초록

An apparatus for and method of displacing a body, such as a projectile, piston, or the distal edge of a sunshade cover or energy absorbing honeycomb matrix, utilizing momentum generated by the rapid actuation of an active material element, such as a Martensitic shape memory alloy wire.

대표청구항 ▼

1. An apparatus adapted to perform work, and comprising: an active material actuator securely connected to a fixed structure, and operable to undergo an instance of a reversible change in shape when exposed to and/or occluded from an activation signal, so as to be activated and deactivated respectiv

1. An apparatus adapted to perform work, and comprising: an active material actuator securely connected to a fixed structure, and operable to undergo an instance of a reversible change in shape when exposed to and/or occluded from an activation signal, so as to be activated and deactivated respectively, wherein the instance of the change in shape causes at least a portion of the actuator to travel a first distance;a body located at a first position, drivenly communicating with the actuator and separable from the actuator, and translatable over a second distance greater than the first, so as to continue to travel separate from the actuator after the actuator has been fully activated in order to achieve a second position; anda signal source communicatively coupled to the actuator, and operable to cause the instance of the change in shape over a maximum period, said at least the portion and the source being cooperatively configured to transfer a minimum momentum to the body, so as to impart an impulse upon the body and transfer kinetic energy to the body that cause the body to travel the second distance, as a result of the instance of the change in shape. 2. The apparatus as claimed in claim 1, wherein the actuator includes at least one Martensitic shape memory alloy wire. 3. The apparatus as claimed in claim 1, wherein the actuator includes at least one dielectric elastomer actuator. 4. The apparatus as claimed in claim 2, wherein the wire presents a bowstring configuration having a maximum height to hypotenuse ratio. 5. The apparatus as claimed in claim 1, wherein the body composes a stowed sunshade, and the actuator is operable to selectively deploy the sunshade when activated. 6. The apparatus as claimed in claim 1, wherein the body is connected to a collapsed deformation energy absorber, the actuator is operable to selectively cause the absorber to expand, as a result of the instance of the change in shape, and the momentum is transferred to the body as a result of causing the absorber to expand. 7. The apparatus as claimed in claim 1, further comprising: a return mechanism drivenly coupled to the body, exerting a force antagonistic to the momentum, and operable to cause the body to translate back to the first position, when the body is in the second position. 8. The apparatus as claimed in claim 7, further comprising: a locking mechanism configured to autonomously engage and retain the body at the second position. 9. The apparatus as claimed in claim 7, wherein the return mechanism is a spring, gravity, fluid pressure, or output of an adjacent system. 10. The apparatus as claimed in claim 9, wherein the return mechanism is a spring consisting of an active material. 11. The apparatus as claimed in claim 1, wherein the actuator includes a plurality of parallel shape memory alloy wires operable to create kinetic energy in, through the rapid acceleration of, the body, and activating differing subsets of the wires causes the body to travel over differing second distances and/or at differing velocities, so as to achieve differing second positions and/or differing second position velocities. 12. The apparatus as claimed in claim 1, wherein the body is a piston; and wherein the apparatus further includes a solid mass fixedly coupled to said at least portion of the actuator and operable to strike the piston when the actuator is activated. 13. The apparatus as claimed in claim 12, wherein the mass and piston are coaxially aligned with, and translatably disposed within a cylinder, the mass interconnects a plurality of shape memory elements externally disposed relative to the cylinder, and the cylinder defines at least one slot in a side of the cylinder so as to enable interconnection between the mass and elements. 14. The apparatus as claimed in claim 13, wherein the second distance defines a resultant stroke length, and at least one stop inter-engages the piston and cylinder and is operable to adjust the first position and stroke length. 15. The apparatus as claimed in claim 13, further comprising: at least one damper fixedly secured relative to the cylinder, and operable to selectively engage the piston or mass and damp out vibrations arising from translating the piston and/or mass. 16. The apparatus as claimed in claim 15, wherein said at least one damper consists of an active material operable to attenuate the vibrations. 17. The apparatus as claimed in claim 1, further comprising: an activation source operable to deliver a minimum activation signal to the actuator over a maximum period, so as to effect a rapid activation. 18. The apparatus as claimed in claim 17, wherein the source includes a capacitor presenting a minimum rating based on the cross-sectional area of the actuator. 19. A method of displacing a body a first distance, comprising the steps of: a. activating at least one shape memory alloy element physically communicating with the body and securely connected to a fixed structure, over a maximum period;b. causing a shape memory effect within the element, wherein at least a portion of the element is caused to travel a second distance less than the first, as a result of activating the element;c. imparting kinetic energy to the body, as a result of causing the shape memory effect; andd. displacing the body separate from the element as a result of imparting kinetic energy thereto, the body continuing to travel separate from the element after the element has been fully activated in order to achieve the first distance. 20. The method as claimed in claim 19, wherein step a) further includes the steps of pre-straining the element prior to activation. 21. The method as claimed in claim 19, wherein the element presents a Martensitic shape memory alloy wire having a mean cross-sectional diameter equal to 0.15 mm, and step a) further includes the steps of Joule heating the element by passing a 650 mA current through the element.