US3821685A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally responsive non resettable electric switch
Assignee: GTE Sylvania Inc
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Filing: 1973-10-29
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Granted: 1974-06-28
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Expires: 1993-10-29
Abstract
Abstract An electric switch comprises a glass cylindrical envelope having lead-in wires disposed at each end thereof along the central axis of the cylinder. A conical end closure connected to one of the lead-in wires electrically contacts a slotted can within the envelope. Electrical contact between the slotted can and the second lead-in wire is established, utilizing a coil spring and a pellet of meltable material. When the switch attains a temperature high enough to melt the pellet, the switch opens.
Inventors
- 👤 S Kimball
- 👤 B Warren
- 👤 D Brooks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:26
CPC Classifications
H; H01; H01H; H01H37/00; H01H37/74; H01H37/76; H01H37/764
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
112 words
A thermally responsive non-resettable electric switch comprising: a cylindrical glass envelope having metal closures sealed to each end thereof; lead-in wires at each end of said envelope disposed along the axis thereof; a conical end closure fastened to the internal end of one of said lead-in wires; a cylindrical head fastened to the internal end of the other leadin wire; a longitudinally slotted can disposed within said envelope and providing electrical continuity between said conical end closure and said cylindrical head; a pellet of meltable material disposed at one end of said envelope; and a coil spring, in compression, disposed within said slotted can between the bottom thereof and said cylindrical head.
Claim 2
Dependent Claim
112 words
A thermally responsive non-resettable electric switch comprising: a cylindrical glass envelope having metal closures sealed to each end thereof; lead-in wires at each end of said envelope disposed along the axis thereof; a conical end closure fastened to the internal end of one of said lead-in wires; a cylindrical head fastened to the internal end of the other leadin wire; a longitudinally slotted can disposed within said envelope and providing electrical continuity between said conical end closure and said cylindrical head; a pellet of meltable material disposed at one end of said envelope; and a coil spring, in compression, disposed within said slotted can between the bottom thereof and said cylindrical head.
Claim 3
Dependent Claim
26 words
The switch of claim 1 wherein the open end of said slotted can is slightly tapered and is in frictional engagement with said conical end closure.
Claim 4
Dependent Claim
26 words
The switch of claim 1 wherein said cylindrical head has sufficient engagement with the interior walls of said slotted can to provide good electrical contact therEbetween.
Claim 5
Dependent Claim
32 words
The switch of claim 1 wherein said pellet has a predetermined melting temperature upon attainment of which said spring forces said slotted can out of electrical contact with said conical end closure.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |