Claims
- 1. A linear actuator, including:
a plurality of links disposed in closely spaced array and adapted to undergo reciprocal translation in a longitudinal direction: an output shaft connected to said plurality of links and adapted to undergo reciprocal translation in said longitudinal direction; said plurality of links each having a common geometric form adapted for stacking in a predetermined array with respect to said output shaft; a plurality of shape memory wires connected to said plurality of links in serial, contiguous fashion; means for heating said shape memory wires beyond the memory transition temperature to contract said wires and urge said links to move in said longitudinal direction in displacement multiplied fashion.
- 2. The linear actuator of claim 1, wherein said means for heating includes an electrical circuit extending through all of said SMA wires and all of said links.
- 3. The linear actuator of claim 2, wherein said plurality of links are divided into a plurality of separate groups, each of said groups being mechanically and electrically connected by said SMA wires in serial, contiguous, displacement multiplied fashion.
- 4. The linear actuator of claim 3, wherein said plurality of separate groups are mechanically connected between a mechanical ground and said output shaft.
- 5. The linear actuator of claim 4, wherein said mechanical ground comprises a housing formed to extend about said plurality of links and plurality of wires.
- 6. The linear actuator of claim 4, wherein each of said groups includes a first SMA wire connected from said mechanical ground to a first link in the group, and a last SMA wire connected from a last link in the group to said output shaft.
- 7. The linear actuator of claim 6, wherein said housing includes at least one electrical connector disposed to connect to said first SMA wire at said mechanical ground.
- 8. The linear actuator of claim 6, wherein all of said groups are electrically connected at said output shaft as a common node.
- 9. The linear actuator of claim 3, wherein two separate groups of links are disposed at opposite sides of said output shaft, said output shaft extending and retracting from a medial position in said closely spaced array.
- 10. The linear actuator of claim 1, wherein said plurality of links each have a trigon configuration comprised of three generally identical planar faces extending in said longitudinal direction and oriented by an equilateral triangular cross-section of each link.
- 11. The linear actuator of claim 10, further including a wire groove extending longitudinally along a longitudinal bisector line of each of said planar faces.
- 12. The linear actuator of claim 11, further including a crimp pocket formed in each of said planar faces at one end of said wire groove.
- 13. The linear actuator of claim 12, further including a crimp applied to one end of one of said SMA wires and driven into said crimp pocket, said crimp being below the surface of the respective planar face.
- 14. The linear actuator of claim 13, wherein said crimp forms an electrical connection through said crimp pocket to said link.
- 15. The linear actuator of claim 14, wherein said links are formed of a conductive material, and said links are coated with an electrically insulating material.
- 16. The linear actuator of claim 11, wherein said links are disposed in face-to-face abutment in said closely spaced array,
- 17. The linear actuator of claim 16, wherein said wire grooves of two of said planar faces in abutment together define a wire channel for retaining one of said SMA wires in an intrinsic return fashion.
- 18. The linear actuator of claim 10, wherein said output shaft includes a plurality of said planar faces extending longitudinally thereon and adapted to abut said planar faces of said links in complementary fashion.
- 19. The linear actuator of claim 18, wherein said output shaft includes a hexagonal portion wherein each facet of said hexagonal portion comprises one of said planar faces.
- 20. The linear actuator of claim 19, wherein said predetermined array includes eighteen of said links stacked about said hexagonal portion and defining an hexagonal outer configuration of said predetermined array.
- 21. The linear actuator of claim 20, wherein said plurality of links are mechanically and electrically connected by said SMA wires in serial, contiguous, displacement multiplied fashion.
- 22. The linear actuator of claim 21, wherein said plurality of links are divided into a plurality of separate groups, each of said groups being mechanically and electrically connected by said SMA wires in serial, contiguous, displacement multiplied fashion.
- 23. The linear actuator of claim 22, wherein each of said groups includes a first SMA wire connected from a mechanical ground to a first link in the group, and a last SMA wire connected from a last link in the group to said output shaft.
- 24. The linear actuator of claim 23, wherein said mechanical ground includes a housing formed to extend about said plurality of links and plurality of wires and said shaft.
- 25. The linear actuator of claim 24, wherein said housing includes a tubular member having an inner bore configured to receive said hexagonal outer configuration of said predetermined array of links.
- 26. The linear actuator of claim 25, wherein said housing includes at least one electrical connector disposed to connect to said first SMA wire at said mechanical ground.
- 27. The linear actuator of claim 26, wherein all of said groups are electrically connected at said output shaft as a common node.
- 28. The linear actuator of claim 25, wherein said housing includes a pair of end caps secured in opposed ends of said inner bore.
- 29. The linear actuator of claim 28, further including a central passage in at least one of said end caps through which a portion of said output shaft may extend.
- 30. The linear actuator of claim 18 wherein said output shaft includes a rhomboid portion wherein each facet of said rhomboid portion comprises one of said planar faces.
- 31. The linear actuator of claim 30, wherein said predetermined array includes fourteen of said links stacked about said rhomboid portion and defining a rhomboidal outer configuration of said predetermined array.
- 32. The linear actuator of claim 31, wherein said plurality of links are mechanically and electrically connected by said SMA wires in serial, contiguous, displacement multiplied fashion.
- 33. The linear actuator of claim 32, wherein said plurality of links are divided into a plurality of separate groups, each of said groups being mechanically and electrically connected by said SMA wires in serial, contiguous, displacement multiplied fashion.
- 34. The linear actuator of claim 33, wherein each of said groups includes a first SMA wire connected from a mechanical ground to a first link in the group, and a last SMA wire connected from a last link in the group to said output shaft.
- 35. The linear actuator of claim 34, wherein said mechanical ground comprises a housing formed to extend about said plurality of links and plurality of wires and said shaft.
- 36. The linear actuator of claim 35, wherein said housing includes a tubular member having an inner bore configured to receive said rhomboidal outer configuration of said predetermined array of links.
- 37. The linear actuator of claim 1, wherein said plurality of links each have a chevron configuration comprised of a longitudinally extending member having a generally rectangular cross-section.
- 38. The linear actuator of claim 37, wherein each link includes a pair of longitudinally extending flanges projecting outwardly from laterally opposed edges of an upper surface of each link.
- 39. The linear actuator of claim 38, wherein each link includes a pair of longitudinally extending bevels along laterally opposed edges of a lower surface of each link.
- 40. The linear actuator of claim 39, wherein said links are adapted for vertical stacking in which said pair of bevels of each link is received in nesting relationship to said pair of flanges extending from the subjacent link in said vertical stack.
- 41. The linear actuator of claim 40, further including a wire groove extending longitudinally along a longitudinal bisector line of each of said upper and lower surfaces.
- 42. The linear actuator of claim 41, further including a crimp pocket formed in each of said upper and lower surfaces at one end of said wire groove.
- 43. The linear actuator of claim 42, wherein said links are formed of a conductive material, and said links are coated with an electrically insulating material.
- 44. The linear actuator of claim 43, wherein said links and said SMA wires are connected mechanically and electrically in contiguous, serial fashion for displacement multiplied reciprocal motion.
- 45. The linear actuator of claim 44, wherein said links are formed of a conductive material, and said links are coated with an electrically insulating material.
- 46. The linear actuator of claim 16, wherein said wire grooves of two of said upper and lower surfaces in abutment in said vertical stack together define a wire channel for retaining one of said SMA wires in an intrinsic return fashion.
- 47. The linear actuator of claim 44, wherein said plurality of links are divided into two separate groups, each of said groups being mechanically and electrically connected by said SMA wires in serial, contiguous, displacement multiplied fashion.
- 48. The linear actuator of claim 47, wherein each of said groups includes a first SMA wire connected from a mechanical ground to a first link in the group, and a last SMA wire connected from a last link in the group to said output shaft.
- 49. The linear actuator of claim 48, wherein said mechanical ground includes a housing formed to extend about said plurality of links and plurality of wires and said shaft.
- 50. The linear actuator of claim 49, wherein said housing includes a tubular member having an inner bore configured to receive rectangular outer configuration of said predetermined array of links.
- 51. The linear actuator of claim 50, wherein said housing includes at least one electrical connector disposed to connect to said first SMA wire at said mechanical ground.
- 52. The linear actuator of claim 51, wherein both of said groups are electrically connected at said output shaft as a common node.
- 53. The linear actuator of claim 50, wherein said housing includes a pair of end caps secured in opposed ends of said inner bore.
- 54. The linear actuator of claim 53, further including a central passage in at least one of said end caps through which a portion of said output shaft may extend.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application Ser. No. 10/056,233, filed Dec. 3, 2001, and issued as U.S. Pat. No. 6,762,515 on Jul. 13, 2004, which is a continuation of application Ser. No. 09/566,446, filed May 8, 2000 and issued as U.S. Pat. No. 6,326,707 on Dec. 4, 2001, for which priority is claimed.
Continuations (1)
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Number |
Date |
Country |
Parent |
09566446 |
May 2000 |
US |
Child |
10056233 |
Dec 2001 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
10056233 |
Dec 2001 |
US |
Child |
10889814 |
Jul 2004 |
US |