US4435229A
Expired / Lapsed
US
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Method of preparing a two-way shape memory alloy
Assignee: Individual
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Filing: 1981-10-02
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Granted: 1984-03-06
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Expires: 2001-10-02
Abstract
Abstract A two-way shape memory alloy, a method of training a shape memory alloy, and a heat engine employing the two-way shape memory alloy to do external work during both heating and cooling phases. The alloy is heated under a first training stress to a temperature which is above the upper operating temperature of the alloy, then cooled to a cold temperature below the zero-force transition temperature of the alloy, then deformed while applying a second training stress which is greater in magnitude than the stress at which the alloy is to be operated, then heated back to the hot temperature, changing from the second training stress back to the first training stress.
Inventors
- 👤 Alfred D. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:47
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/006
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
156 words
A method of training a shape memory alloy so that the alloy has a two-way shape memory when the alloy is operated in a working cycle for converting heat into mechanical work with the conditions of the cycle including an upper operating temperature T of the alloy and a stress σ w at which the alloy is operated in the working cycle, the method comprising iteratively performing the steps of heating the alloy under a first training stress σ 1 to a temperature T H which is above said temperature T, cooling the alloy to a temperature T C which is below the zero-force transition temperature of the alloy, deforming the alloy at T C while applying to the alloy a second training stress σ 2 where σ 2 ≠σ 1 and σ 2 ≧σ w , heating the alloy back to T H , and changing stress on the alloy to the first training stress.
Claim 2
Independent Claim
156 words
A method of training a shape memory alloy so that the alloy has a two-way shape memory when the alloy is operated in a working cycle for converting heat into mechanical work with the conditions of the cycle including an upper operating temperature T of the alloy and a stress σ w at which the alloy is operated in the working cycle, the method comprising iteratively performing the steps of heating the alloy under a first training stress σ 1 to a temperature T H which is above said temperature T, cooling the alloy to a temperature T C which is below the zero-force transition temperature of the alloy, deforming the alloy at T C while applying to the alloy a second training stress σ 2 where σ 2 ≠σ 1 and σ 2 ≧σ w , heating the alloy back to T H , and changing stress on the alloy to the first training stress.
Claim 3
Dependent Claim
23 words
A method as in claim 1 in which the first training stress is applied in an opposite sense from the second training sense.
Claim 4
Dependent Claim
15 words
A method as in claim 2 in which said training stresses are applied in torsion.
Claim 5
Dependent Claim
17 words
A method as in claim 2 in which said training stresses are applied in tension and compression.
Claim 6
Dependent Claim
15 words
A method as in claim 2 in which said training stresses are applied in shear.
Claim 7
Dependent Claim
26 words
A method as in claim 1 in which the training stresses are applied in the same sense and in which the stresses are of different magnitude.
Claim 8
Dependent Claim
15 words
A method as in claim 6 in which said training stresses are applied in torsion.
Claim 9
Dependent Claim
17 words
A method as in claim 6 in which said training stresses are applied in tension or compression.
Claim 10
Dependent Claim
15 words
A method as in claim 6 in which said training stresses are applied in shear.
Claim 11
Dependent Claim
29 words
A method as in claim 1 in which the shape memory alloy comprises Nitinol having a composition of substantially 55% nickel by weight and substantially 45% titanium by weight.
Claim 12
Dependent Claim
19 words
A method as in claim 10 in which the alloy is deformed substantially 3% dimensionally by the training stresses.
Claim 13
Dependent Claim
17 words
A method as in claim 10 in which one of the training stresses is substantially 30 Kpsi.
Claim 14
Dependent Claim
20 words
A method as in claim 10 in which T H is substantially 95° C. and T C substantially 5° C.
Claim 15
Dependent Claim
44 words
A method as in claim 10 in which the alloy is deformed substantially 3% dimensionally by applying said training stresses, one of said stresses is at substantially 30 Kpsi, said T H is substantially 95° C. and said T C is substantially 5° C.
Claim 16
Dependent Claim
158 words
A shape memory alloy having a two-way shape memory which produces mechanical work during both heating and cooling cycles when operated in a shape memory alloy heat engine with the conditions including an operating temperature T of the alloy and a stress σ w at which the alloy is operated in the working cycle, said alloy being formed by the method of iteratively performing the steps of heating a naive shape memory alloy under a first training stress σ 1 to a temperature T H which is above the upper operating temperature T of the alloy, cooling the alloy to a temperature T C which is below the zero-force transition temperature of the alloy, deforming the alloy at T C while applying a second training stress σ 2 where σ 2 ≠σ 1 and σ 2 ≧σ w , heating the alloy back to T H , and changing stress on the alloy to the first training stress.
Claim 17
Dependent Claim
158 words
A shape memory alloy having a two-way shape memory which produces mechanical work during both heating and cooling cycles when operated in a shape memory alloy heat engine with the conditions including an operating temperature T of the alloy and a stress σ w at which the alloy is operated in the working cycle, said alloy being formed by the method of iteratively performing the steps of heating a naive shape memory alloy under a first training stress σ 1 to a temperature T H which is above the upper operating temperature T of the alloy, cooling the alloy to a temperature T C which is below the zero-force transition temperature of the alloy, deforming the alloy at T C while applying a second training stress σ 2 where σ 2 ≠σ 1 and σ 2 ≧σ w , heating the alloy back to T H , and changing stress on the alloy to the first training stress.
Claim 18
Dependent Claim
28 words
A shape memory alloy formed by the method of claim 15 in which the first training stress is applied in an opposite sense from the second training stress.
Claim 19
Dependent Claim
18 words
An alloy formed by the method of claim 16 in which said training stresses are applied in torsion.
Claim 20
Dependent Claim
20 words
An alloy formed by the method of claim 16 in which said training stresses are applied in tension and compression.
Claim 21
Dependent Claim
18 words
An alloy formed by the method of claim 16 in which said training stresses are applied in shear.
Claim 22
Dependent Claim
29 words
An alloy formed by the method of claim 15 in which the training stresses are applied in the same sense and in which the stresses are of different magnitude.
Claim 23
Dependent Claim
18 words
An alloy formed by the method of claim 20 in which said training stresses are applied in torsion.
Claim 24
Dependent Claim
20 words
An alloy formed by the method of claim 20 in which said training stresses are applied in tension or compression.
Claim 25
Dependent Claim
18 words
An alloy formed by the method of claim 20 in which said training stresses are applied in shear.
Claim 26
Dependent Claim
33 words
A shape memory alloy formed by the method of claim 15 in which the naive alloy comprises Nitinol having a composition of substantially 55% nickel by weight and substantially 45% titanium by weight.
Claim 27
Dependent Claim
23 words
An alloy formed by the method of claim 24 in which the alloy is deformed substantially 3% dimensionally while applying said training stresses.
Claim 28
Dependent Claim
20 words
An alloy formed by the method of claim 24 in which one of said training stresses is substantially 30 Kpsi.
Claim 29
Dependent Claim
24 words
An alloy formed by the method of claim 24 in which T H is substantially 95° C. and T C is substantially 5° C.
Claim 30
Dependent Claim
46 words
An alloy formed by the method of claim 24 in which the naive alloy is deformed substantially 3% dimensionally by applying said training stresses, one of said stresses is substantially 30 Kpsi, said T H is substantially 95° C. and T C is substantially 5° C.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |