US4299889A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contact for vacuum interrupter
Assignee: Mitsubishi Electric Corp
•
Filing: 1979-05-21
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Granted: 1981-11-10
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Expires: 1999-05-21
Abstract
Abstract A contact for a vacuum interrupter has excellent characteristics of high withstand voltage, large current durability and low chopping current and is prepared by infiltrating copper into a skeleton obtained by sintering a specific tungsten powder having an average diameter of less than 1 μm. The skeleton is preferably prepared by a vacuum sintering process and the copper is infiltrating into the skeleton in hydrogen atmosphere or in vacuum.
Inventors
- 👤 Masaru Kato
- 👤 Hitoshi Takeuchi
- 👤 Toshiaki Horiuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:12
CPC Classifications
H; H01; H01H; H01H1/00; H01H1/02; H01H1/0203; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12014; Y10T428/1216; Y10T428/12167; Y10T428/12174
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
36 words
A contact for a vacuum interrupter which is prepared by infiltrating from 4.5 to 14 wt. % of copper into a skeleton formed by sintering tungsten powder having an average diameter of less than 1 μm.
Claim 2
Dependent Claim
36 words
A contact for a vacuum interrupter which is prepared by infiltrating from 4.5 to 14 wt. % of copper into a skeleton formed by sintering tungsten powder having an average diameter of less than 1 μm.
Claim 3
Dependent Claim
30 words
A contact for a vacuum interrupter according to claim 1 wherein a ratio of apparent density to true density of the skeleton of tungsten is ranging from 70% to 90%.
Claim 4
Dependent Claim
26 words
A contact for a vacuum interrupter according to claim 1 wherein copper is infiltrated into the skeleton of tungsten in a hydrogen atmosphere or in vacuum.
References Cited (Backward Citations)
CA836115A
Cited
US2034550A
Cited
US2391456A
Cited
US3153163A
Cited
US3438753A
Cited
US3489530A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-09 | 1985-05-11 | 1985-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-09 | 1989-05-11 | 1989-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-09 | 1993-05-11 | 1993-11-10 | $7700.00 | Window Closed / Lapsed |