QUICK-RETURN ACTIVE MATERIAL ACTUATOR

• US 20120297763A1
• Filed: 05/24/2011
• Published: 11/29/2012
• Est. Priority Date: 05/24/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Mankame, Nilesh D., Skurkis, Richard J., Kramarczyk, Mark A., Alexander, Paul W.
• Granted Patent: US 9,234,509 B2
• Time in Patent Office: Days
• US Class Current: 60/527
• CPC Class Codes: F03G 7/065 using a shape memory element
• CPC Class Codes: Y02E 10/46 Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines

Abstract

A quick-return active material actuator adapted for more rapidly returning a load, so as to reduce the de-actuation time of a system, includes in a first aspect a thermally activated active material actuation element drivenly coupled to the load, an active material de-actuation element drivenly coupled to the load non-antagonistic to the actuation element, and a reconfigurable mechanism interconnecting the elements and load, wherein the de-actuation element and mechanism are cooperatively configured to return the load while the actuation element is still activated, and, in a second aspect a thermally activated active material actuation element drivenly coupled to a biased load and operable to autonomously release, so that the load is caused to be returned while the actuation element is still activated, and subsequently re-engage the load.

Claims

1. A quick-return actuator adapted for more rapidly returning a load, so as to decrease the de-actuation of a system, said actuator comprising:

an actuating active material element operable to undergo a first reversible change in fundamental property when exposed to a first external signal, so as to be activated, and drivenly connectable to the load, such that the first change causes the load to move from a home position and to a first position; and

a de-actuating active material element non-antagonistic to the actuating element, operable to undergo a second reversible change in fundamental property when exposed to a second external signal, so as to be activated, and drivenly connectable to the load, such that the second change causes the load to move to a second position, when the load is in the first position,

said elements being cooperatively configured such that the actuating element is configured to move the load to the first position when the load is in the second position and both changes are reversed.

2. The actuator as claimed in claim 1, wherein the actuating and/or de-actuating active material element includes a shape memory alloy wire.

3. The actuator as claimed in claim 1, further comprising:

a reconfigurable mechanism drivenly coupled to the actuating active element and load, and configured to shift from a first and to a second configuration as a result of the second change, such that the load achieves the second position as a result of shifting the mechanism to the second configuration.

4. The actuator as claimed in claim 3, wherein the mechanism includes first and second relatively translatable members, the second member is drivenly coupled to the de-actuating active element, such that the second change causes the second member to translate relative to the first member, and the mechanism is caused to shift to the second configuration by translating the second member.

5. The actuator as claimed in claim 4, wherein at least a portion of the second member is tubular and defines an interior space, and at least a portion of the first member is disposed within the space.

6. The actuator as claimed in claim 4, wherein the mechanism defines at least one adjustable stop configured to impose a prescribed pre-load on the spring that constrains the relative motion of the first and second translatable members.

7. The actuator as claimed in claim 4, wherein the mechanism further includes a biasing member drivenly coupled to the first and second members, so as to produce a biasing force thereupon, wherein the force drives the mechanism towards the first configuration, and the second change is configured to overcome the force and cause the second member to translate relative to the first member.

8. The actuator as claimed in claim 7, wherein the de-actuation element presents an SMA wire, and the wire and the first, second, and biasing members are cooperatively configured such that the biasing member imposes a prescribed pre-load on the second member when the load is in the home position.

9. The actuator as claimed in claim 1, wherein the de-actuation element is a wire presenting an available functional length and effective stroke, and further comprising:

at least one pulley entraining the de-actuation element, so as to bend the wire and increase the effective stroke of the de-actuation element.

10. The actuator as claimed in claim 9, wherein said at least one pulley and de-actuation element are cooperatively configured, so as to provide mechanical advantage to the de-actuation element.

11. The actuator as claimed in claim 1, further comprising:

a power source communicatively coupled to the second element, and operable to generate the second signal; and

a controller communicatively coupled to the elements, the external load, the operating environment, and the power source, and programmably configured to control the second signal based on inferred states and/or internal logic.

12. The actuator as claimed in claim 11, further comprising:

at least one sensor and/or input device communicatively coupled to the controller, and operable to determine an event/condition and deliver an input to the controller when the event/condition is determined, wherein said at least one sensor and/or input device and controller are cooperatively configured to manipulate the signal when the event/condition is determined.

13. The actuator as claimed in claim 1, wherein the actuation element presents a bow-string configuration, and engages the load medially.

14. The actuator as claimed in claim 3, wherein the mechanism includes first and second pivot arms defining pivot axes.

15. The actuator as claimed in claim 14, wherein the pivot axes define upper and lower sections of the arms, the elements are drivenly connected to one of the upper and lower sections, and further comprising:

an overload spring drivenly connected to the other of said upper and lower sections.

16. A quick-release actuator adapted for autonomously releasing a biased load, so as to decrease the de-actuation time of a system, said actuator comprising:

a driven member operable to engage the load; and

a first active material element operable to undergo a reversible change in fundamental property when exposed to an external signal, so as to be activated, and drivenly coupled to the member, wherein the change is configured to move the load from an original and to a first position and autonomously disengage the member and load when the load achieves the first position, so that the load is able to move back to the original position.

17. The actuator as claimed in claim 16, further comprising:

a fixed structure defining a sloped surface, wherein the member defines a chamfered edge, and the sloped surface and chamfered edge are cooperatively configured to autonomously disengage the member from the load, when the load achieves the first position.

18. The actuator as claimed in claim 16, further comprising:

a biasing member drivenly coupled to the load, and configured to return the load to the original position, when the driven member and load are disengaged.

19. The actuator as claimed in claim 18, wherein the biasing member includes a spring drivenly coupled to the load.

20. The actuator as claimed in claim 16, further comprising:

a reset mechanism drivenly coupled to the driven member, antagonistic to the first active element, and configured to autonomously re-engage the member and load when the change is reversed and the load returns to the original position.

21. The actuator as claimed in claim 20, wherein the reset mechanism includes a spring drivenly coupled to the driven member.