Patent US2429769A successfully refreshed from Google Patents.
US4060787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal switch
Assignee: Elmwood Sensors Inc
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Filing: 1976-11-12
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Granted: 1977-11-29
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Expires: 1996-11-12
Abstract
Abstract A thermal switch having a tubular metal casing within which a fusible pellet normally holds an axially slidable electrical contact disk in contact with an electrical lead. The body of the electrical lead extends through a ceramic bushing and out of the casing for electrical connection, and it is formed with at least one radially-extending relief lying within the bore of the ceramic bushing. A sealing resin within the bore of the ceramic bushing and around the lead retains the lead in the bushing both in normal use and after the fusible pellet has melted and the electrical connection is broken.
Inventors
- 👤 Frederick Budnik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:20
CPC Classifications
H; H01; H01H; H01H37/00; H01H37/74; H01H37/76; H01H37/764; H01H37/765
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
253 words
A thermal switch comprising: a tubular, electrically and thermally conductive metal casing, a first electrically conductive lead joined to and extending from one end of said metal casing to seal off said one end and make electrical connection to said casing, an insulative ceramic bushing at the opposite end of said casing, said bushing sealing said opposite end of said casing and having its bore coaxial with said casing, a normally solid, fusible pellet within said casing adjacent to said one end, a second electrically conductive lead having a generally cylindrical body extending through the bore of said ceramic bushing and out of said casing to permit electrical connection thereto, and having a head abutting the end of said ceramic bushing within said casing, said body of said second lead being formed with at least one radially-extending relief lying within the bore of said ceramic bushing, said relief extending around less than the entire circumference of said body, said second lead being retained in said ceramic bushing by a sealing resin within the bore of said bushing around the body of said second lead, an electrically conductive disk positioned within said casing between said fusible pellet and said head of said second lead coaxial with said casing, slidable axially within said casing and making electrical contact with the wall of said casing, and resilient means urging said disk into electrical contact with the head of said second lead when said fusible pellet is solid and away therefrom upon melting of said fusible pellet.
Claim 2
Dependent Claim
253 words
A thermal switch comprising: a tubular, electrically and thermally conductive metal casing, a first electrically conductive lead joined to and extending from one end of said metal casing to seal off said one end and make electrical connection to said casing, an insulative ceramic bushing at the opposite end of said casing, said bushing sealing said opposite end of said casing and having its bore coaxial with said casing, a normally solid, fusible pellet within said casing adjacent to said one end, a second electrically conductive lead having a generally cylindrical body extending through the bore of said ceramic bushing and out of said casing to permit electrical connection thereto, and having a head abutting the end of said ceramic bushing within said casing, said body of said second lead being formed with at least one radially-extending relief lying within the bore of said ceramic bushing, said relief extending around less than the entire circumference of said body, said second lead being retained in said ceramic bushing by a sealing resin within the bore of said bushing around the body of said second lead, an electrically conductive disk positioned within said casing between said fusible pellet and said head of said second lead coaxial with said casing, slidable axially within said casing and making electrical contact with the wall of said casing, and resilient means urging said disk into electrical contact with the head of said second lead when said fusible pellet is solid and away therefrom upon melting of said fusible pellet.
Claim 3
Dependent Claim
28 words
The thermal switch of claim 1 wherein each said relief has a depth of 2 to 15 percent of the diameter of said body of said second lead.
Claim 4
Dependent Claim
39 words
The thermal switch of claim 1 wherein said body of said second lead is formed with a plurality of said reliefs in the form of a plurality of radial indentations formed in each of a plurality of circumferential rings.
Claim 5
Dependent Claim
19 words
The thermal switch of claim 3 wherein each circumferential ring of radial indentations consists of four equally spaced indentations.
Claim 6
Dependent Claim
28 words
The thermal switch of claim 3 wherein each said indentation has a depth of 2 percent to 15 percent of diameter of said body of said second lead.
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) | 1980-11-28 | 1981-05-30 | 1981-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-28 | 1985-05-30 | 1985-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-28 | 1989-05-30 | 1989-11-29 | $7700.00 | Window Closed / Lapsed |