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US 8,797,703 B2Granted
Active material actuator having a magnetorheological overload protector
AssigneeGM Global Technology Operations LLC
InventorAlan L. Browne
Life of this patent
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Abstract
A system for and method of providing overload protection for actuators, such as shape memory alloy wires, including and utilizing a magnetorheological fluid mechanism connected in series with or parallel to the load driven by the actuator, and operable to effect tunable protection.
Claims20
An active material actuation system adapted for driving a load over an actuation cycle, and preventing an overload condition during the cycle, the system comprising:
- an actuator defining a maximum threshold force, and drivenly coupled to the load, so as to apply a driving force thereto;
- a fixed structure coupled to the actuator;
- and
- an overload protector, including:
- a mechanism further including magnetorheological fluid defining a yield strength, and a translatable part disposed within the fluid;
- and
- at least one magnet communicatively coupled to the fluid, so as to further define the yield strength, the protector producing a selectively modifiable resistive force based on the yield strength, wherein the resistive force is less than the maximum threshold force, the mechanism being driven by the actuator such that the resistive force opposes the driving force, and caused to reconfigure, so as to create a secondary work output path, when the driving force is greater than the resistive force.
4 more elements
Dependencies are inferred from the claim text.