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US3622932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-restoring thermal switch with means for indicating previous overtemperature condition
Assignee: International Business Machines Corp
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Filing: 1970-07-16
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Granted: 1971-11-23
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Expires: 1990-07-16
Abstract
Abstract A thermally operated switch which utilizes a bimetallic diaphragm. When an overtemperature condition inverts the diaphragm, the diaphragm pushes up a plunger by a sufficient amount to enable a spring to take over and push the plunger up farther. The spring will then hold the plunger in its up position to provide a visual indication of the existence of the overtemperature condition even after the diaphragm has cooled enough to snap back to its normal position to turn the switch back on.
Inventors
- 👤 Peter J Cunavelis
- 👤 Edmund Joseph Distefano
- 👤 Donald L Osterhoudt Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:00
CPC Classifications
H; H01; H01H; H01H37/00; H01H37/02; H01H37/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
204 words
In a thermal switch for electrical equipment, said switch comprising (1) a temperature-sensitive curved diaphragm which is nOrmally curved in a first direction, which reverses its direction of curvature when heated to a temperature above a predetermined upper threshold, and which returns to its normal direction of curvature when it cools to a temperature below a predetermined lower threshold and (2) means for turning off said switch when said diaphragm reverses its direction of curvature and for turning said switch back on when said diaphragm returns to its normal direction of curvature; the improvement comprising: movable indicating means capable of assuming an indicating position and a nonindicating position; said indicating means, when it is in its nonindicating position, being in close proximity to said diaphragm so that a reversal of the direction of curvature of said diaphragm will drive said indicating means in a direction away from said diaphragm; and a driving spring mounted within said switch in such manner that, when a reversal in the direction of curvature of said diaphragm drives said indicating means away from said diaphragm, a first portion of said spring is forced between said indicating means and said diaphragm to drive said indicating means to its indicating position.
Claim 2
Dependent Claim
204 words
In a thermal switch for electrical equipment, said switch comprising (1) a temperature-sensitive curved diaphragm which is nOrmally curved in a first direction, which reverses its direction of curvature when heated to a temperature above a predetermined upper threshold, and which returns to its normal direction of curvature when it cools to a temperature below a predetermined lower threshold and (2) means for turning off said switch when said diaphragm reverses its direction of curvature and for turning said switch back on when said diaphragm returns to its normal direction of curvature; the improvement comprising: movable indicating means capable of assuming an indicating position and a nonindicating position; said indicating means, when it is in its nonindicating position, being in close proximity to said diaphragm so that a reversal of the direction of curvature of said diaphragm will drive said indicating means in a direction away from said diaphragm; and a driving spring mounted within said switch in such manner that, when a reversal in the direction of curvature of said diaphragm drives said indicating means away from said diaphragm, a first portion of said spring is forced between said indicating means and said diaphragm to drive said indicating means to its indicating position.
Claim 3
Dependent Claim
27 words
The thermal switch of claim 1 further comprising: detent means to hold said indicating means in its indicating position when said switch is automatically turned back on.
Claim 4
Dependent Claim
47 words
The thermal switch of claim 2 wherein said detent means comprises: a notch in said indicating means and a tensioned bulge in a second portion of said spring; said tensioned bulge falling into said notch to hold said indicating means in its indicating position by spring tension.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |