US3753792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of achieving thermally balanced hot wire relay type devices
Assignee: Robertshaw Controls Co
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Filing: 1971-12-09
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Granted: 1973-08-21
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Expires: 1991-12-09
Abstract
Abstract A hot wire relay type device, formed from an alloy composition exhibiting a characteristic of mechanical shape memory as a result of martensitic-type transformation, is produced for use as a heat reactive controller in such manner that the supported terminal portions do not react to heat or, at the very least, heat above the transition temperature simultaneously with the portion of the device intermediate such terminal portions whereby the wire achieves a thermal balance throughout its entire body.
Inventors
- 👤 H Tyler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:00
CPC Classifications
H; H01; H01H; H01H61/00; H01H61/01; H01H61/0107; H01H2061/0115
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
48 words
The method according to claim 1 wherein said step of modification comprises annealing said center portion to obtain a modulus of elasticity change in only said center portion for a change in temperature, the end portions anchored by the clamping means remaining hard throughout the change in temperature.
Claim 2
Dependent Claim
48 words
The method according to claim 1 wherein said step of modification comprises annealing said center portion to obtain a modulus in torsion change in only said center portion for a change in temperature, the end portions anchored by the clamping means remaining hard throughout the change in temperature.
Claim 3
Dependent Claim
48 words
The method according to claim 1 wherein said step of modification comprises prehardening said end portions independent of temperature to have a hardness greater than that of said center portion below said transition temperature whereby the hardness of said end portions is substantially unaffected by said transition temperature.
Claim 4
Dependent Claim
41 words
The method according to claim 1 wherein said step of modification comprises forming said end portions from hard wire segments having substantially no change in hardness at said transition temperature, and welding said segments to the wire forming the center portion.
Claim 5
Dependent Claim
46 words
The method according to claim 1 wherein said step of modification comprises forming said center portion as a helical coil with outwardly diminishing diameter coils with the outermost coils terminating in straight axial projections forming said end portions, whereby stress on the end portions is reduced.
Claim 6
Dependent Claim
56 words
The method according to claim 1 wherein said step of modification comprises forming a coating on said center portion, said coating being of greater thickness at the middle of said wire and tapering in thickness toward the ends, whereby heating of said center portion is retarded with respect to said end portions to achieve thermal balance.
Claim 7
Dependent Claim
60 words
The method according to claim 1 wherein said step of modification comprise wrapping turns of said wire about a pair of large diameter, low mass heat insulators spaced from each other on opposite ends of the center portions, said turns being close together so as to induce self-heating at the end portions and thereby provide thermal balance in said controller.
Claim 8
Independent Claim
158 words
A method for thermally balancing heat reactive controllers formed by an elongated wire of an alloy having temperature actuated mechanical shape memory as a result of martensitic-type transition and having a center reactive portion terminating in a pair of spaced opposite end portions, said center reactive portion having an initial shape above a predetermined transition temperature and a distorted shape below said predetermined temperature, said method comprising the step of modifying the thermal characteristics of one of said center portion and said end portions with respect to the other of said portions, and securing said end portions in spaced clamping means to hold said wire under load in said distorted shape whereby thermal losses from said end portions to said clamping means are compensated for so that heating of said wire to at least said transition temperature causes said wire to substantially uniformly heat throughout its entire length and to resume its initial shape with substantially uniform hardness.
Claim 9
Independent Claim
110 words
A method for heating an elongated wire of martensitic material normally held under load in a distorted configuration by a pair of spaced clamping means secured to opposite end portions forming terminals of a central reactive portion of said wire, said method comprising the step of modifying the thermal characteristics of either a center portion or the end poRtions of said wire to compensate for normal thermal losses from said end portions to said clamping means so that heating of said wire to at least said transition temperature causes said wire to substantially uniformly heat throughout it entire length and to resume its initial undistorted shape with substantially uniform hardness.
References Cited (Backward Citations)
US3285470A
Cited
US3558369A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |