초록 ▼

A preferred rotary actuator includes an actuator assembly having a torque tube formed of a shape memory alloy (SMA), a superelastic NiTinol return spring associated with the torque tube and adapted to bias the torque tube toward an initial position, and a torque tube heating element, especially a th

A preferred rotary actuator includes an actuator assembly having a torque tube formed of a shape memory alloy (SMA), a superelastic NiTinol return spring associated with the torque tube and adapted to bias the torque tube toward an initial position, and a torque tube heating element, especially a thermoelectric device, for switching the SMA to cause rotation to an object connected to the actuator or to generate a torque upon that object. The torque tube (24) includes a proximal end (32) and a distal end (34). The return spring and torque tube are connected at their ends, with the torque tube being pretwisted while in a martensitic state relative to the spring. Activation of the heating element causes the torque tube to enter an austenitic state in which it returns to its previous untwisted configuration. Removal of heat allows the torque tube to return to a martensitic state, when the return spring retwists the torque tube. A unique locking assembly 22 is used with the preferred actuator assembly. A helicopter blade twist rotation system for a rotorcraft blade 200 having a blade root 202 and a tip 204 includes a SMA rotary actuator 18 located within the blade near the blade root, and a passive torque tube (206) located within the blade and having a proximal end connected to the rotary actuator and a distal end connected to the blade near to the blade tip.

대표청구항 ▼

We claim: 1. An actuator for cycling between first and second positions, comprising: first and second shape memory alloy (SMA) material elements trained to shapes in opposition to one another in their respective austentite phases; at least one heating/cooling device thermally connected to at least

We claim: 1. An actuator for cycling between first and second positions, comprising: first and second shape memory alloy (SMA) material elements trained to shapes in opposition to one another in their respective austentite phases; at least one heating/cooling device thermally connected to at least one element, each heating/cooling device being capable of simultaneously heating one SMA element while cooling the other; and a locking assembly associated with at least one SMA element. 2. An actuator according to claim 1, wherein each heating/cooling device includes at least one thermoelectric element. 3. An actuator according to claim 1, wherein each heating/cooling has at least two modes of operation, in a first mode, heating the first element while cooling the second element and, in a second mode, cooling the first element while heating the second element. 4. An actuator for cycling between first and second positions, comprising: a first shape memory alloy (SMA) device trained in its austenite phase in the first position; a second shape memory alloy (SMA) device trained in its austenite phase in the second position, the SMA devices being coupled together in antagonistic relationship; and, at least one thermoelectric element thermally connected to both SMA devices wherein upon application of current in a first direction through the thermoelectric element, the element heating the first SMA device and cooling the second SMA device to return the first SMA device to the first position while deforming the second, coupled SMA device, while upon application of current in an opposite direction through the thermoelectric element causes cooling first SMA device and heating the second SMA device. 5. A method of manufacturing an actuator for cycling between first and second positions, comprising the steps of: training a first shape memory alloy (SMA) device in its austenite phase in the first position; training a second shape memory alloy (SMA) device in its austenite phase in the second position, the SMA devices being trained to shapes in opposition to one another, each SMA device having a respective transition temperature; disposing at least one thermoelectric element in thermal connection with at least the first SMA device; and heating the first SMA device to its transition temperature with the thermoelectric element to cause that SMA device to transition between the first position and the second position. 6. A method of cycling a shape memory alloy (SMA) actuator between first and second positions, said actuator having first and second SMA devices and at least one thermoelectric element disposed in thermal connection with at least one of the SMA devices, comprising the steps of: applying current to the thermoelectric element to heat the first SMA device while cooling the second SMA device, and; switching the current direction to heat the second SMA device while cooling the first SMA device. 7. An actuator for cycling between first and second positions, comprising: at least two elements formed from shape memory alloy (SMA) material and coupled together for antagonistic action; at least one heating/cooling device thermally connected to at least one of the SMA elements and being capable of simultaneously heating one SMA element while cooling the other; and a locking assembly associated with at least one SMA element. 8. An actuator according to claim 7, wherein each heating/cooling device includes at least one thermoelectric element. 9. An actuator for cycling between first and second positions, comprising: an outer tube defining a longitudinal axis; an inner tube disposed within the outer tube, both tubes formed from shape memory alloy (SMA) metal, and mechanically coupled together in antagonistic relationship and, at least one heating/cooling device disposed in thermal contact with at least one SMA tube and being capable of simultaneously heating one SMA tube while cooling the other. 10. An actuator according to claim 9, wherein each heating/cooling device includes at least one thermoelectric element. 11. An actuator according to claim 9, wherein one SMA tube has its austentite state without torsional displacement with respect to the longitudinal axis in the first position while the second SMA tube has its austentite phase without torsional displacement with respect to said longitudinal axis in said second position to achieve the antagonistic mechanical coupling. 12. A rotary actuator for cycling between first and second positions separated by a predetermined number of degrees of rotation, comprising: first and second shape memory alloy (SMA) devices cyclable between first and second shapes and mechanically coupled to provide the rotation; and, at least one heating/cooling device thermally connected to both SMA devices for simultaneously heating one SMA device while cooling the other. 13. An actuator according to claim 12, wherein the heating/cooling device includes at least one thermoelectric element. 14. The actuator of claim 9 further comprising a locking assembly associated with at least one SMA tube. 15. An actuator for cycling between first and second positions, comprising: (a) two shape memory alloy (SMA) devices arranged in antagonistic relationship; and (b) at least one thermoelectric device to control heat flow between the SMA devices and to cause switching between SMA states with active heat transfer between a hotter SMA device and a cooler SMA device. 16. The actuator of claim 15 wherein the SMA devices are torque tubes and further comprising at least one waste heat thermoelectric device associated with each tube to pass waste heat to a heat sink for overall thermal control of the actuator. 17. The actuator of claim 16 wherein the tubes are coupled to a rotocraft blade for imparting blade twist. 18. The actuator of claim 17 wherein the blade functions as the heat sink.