Support arm with reversed elastic and inelastic ranges
View Patent ↗A support arm which utilizes a material with material properties such that the support arm may be easily placed into a position within a range, yet at the edges of this range have elastic properties.
1. A support arm comprising:
a first end;
a second end; and
a main arm section between said first end and said second end, said main arm section having an inelastic central bending range wherein said main arm section has an elastic outer bending range, wherein said elastic outer bending range comprises deflections of said main arm section greater than the deflections of said inelastic central bending range.
2. The support arm of claim 1 wherein said main arm section comprises a shape memory alloy.
3. The support arm of claim 2 wherein said shape memory alloy comprises a NiTi alloy.
4. The support arm of claim 3 wherein the martensite start temperature of the NiTi alloy is below 20 degrees Celsius, and wherein the austenite finish temperature of the NiTi alloy is above 20 degrees Celsius.
5. The support arm of claim 1 wherein said main arm section comprises nitinol.
6. The support arm of claim 5 wherein said main arm section has a tubular cross-section.
7. The support arm of claim 6 wherein said main arm section has a solid cross-section.
8. The support arm of claim 6 wherein said tubular cross-section has a wall thickness in the range of 0.07 mm to 0.12 mm.
9. The support arm of claim 6 wherein said tubular cross-section has an outside diameter in the range of 1.0 mm to 1.5 mm.
10. The support arm of claim 1 wherein said support arm is curved.
11. The support arm assembly of claim 1 comprising a plurality of arm elements, wherein each of said plurality of arm elements have an inelastic central bending range.
12. The support arm assembly of claim 11 wherein each of said plurality of arm elements has an outer elastic bending range, wherein said outer elastic bending range is outside of said inelastic central bending range.
13. The support arm assembly of claim 12 wherein each of said plurality of arm elements comprise a shape memory alloy.
14. The support arm assembly of claim 12 wherein each of said plurality of arm elements comprises a NiTi alloy.
15. The support arm assembly of claim 14 wherein each of said plurality of arm elements has a tubular cross-section.
16. The support arm of claim 14 wherein the martensite start temperature of the NiTi alloy is below 20 degrees Celsius, and wherein the austenite finish temperature of the NiTi alloy is above 20 degrees Celsius.
17. The support arm assembly of claim 14 wherein each of said plurality of arm elements has a solid cross-section.
18. A method for the manufacture of the support arm of claim 1 , said method comprising the steps of:
placing said support arm in an initial position;
heat treating said support arm with a first treatment; and
heat treating said support arm with a second treatment.
19. The method of claim 18 wherein said support arm is NiTi alloy.
20. The method of claim 19 wherein said initial position is curved.
21. The method of claim 19 wherein said first treatment is a heat treatment of about 280-580 degrees Celsius.
22. The method of claim 21 wherein said second treatment is a heat treatment of about 300-550 degrees Celsius.