Memory metal actuator
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorCarl F. Ruoff
Life of this patent
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Abstract
A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.
Claims22
A mechanical actuator comprising:
- a fixed position support element;
- an output element which is movable with respect to the support element;
- a plurality of actuator elements formed of memory metal material, each actuator element having a first end coupled to the support element and a second end coupled to the output element, wherein when an actuator element is heated above a critical temperature it will rapidly attempt to move to a predetermined hot-formed shape;
- and
- control means for selectively heating the actuator elements to control the amount of force exerted against the output element with the forces exerted by the actuator elements being related to each other in a binary fashion.
A memory metal mechanical actuator, comprising:
- a fixed support element;
- an output element which is movable with respect to the support element;
- a plurality of memory metal actuator elements connected between the support element and output element in a mechanically parallel configuration, wherein the actuator elements are malleable when they are below a critical temperature and rapidly attempt to move to a predetermined hot-formed shape when heated above the critical temperature thereby to exert a force on the output element, wherein the stiffnesses of the actuator elements and thus the force exerted by them when moving toward their hot-formed shape have a binary relationship;
- and
- control means for selectively heating the actuator elements above their critical temperature in response to binary control signals.
A mechanical actuator comprising:
- an actuator element formed of a memory metal material, said actuator element being malleable below a critical temperature and rapidly assuming a predetermined hot-formed shape when heated above the critical temperature;
- means for heating the actuator element to the critical temperature to cause it to assume its hot-formed shape;
- and
- cooling means for dissipating heat from the actuator element to cause its temperature to rapidly fall below the critical temperature, said cooling means operating by the Peltier effect.
Dependencies are inferred from the claim text.