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Patent US2720997A successfully refreshed from Google Patents.
US2720997A
Expired / Lapsed
US
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Seal for electron discharge device
Assignee: Westinghouse Electric Corp
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Filing: 1952-04-05
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Granted: 1955-10-18
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Expires: 1972-04-05
Abstract
No abstract record available.
Inventors
- 👤 Hampton J Dailey
- 👤 Donald M Wroughton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:19
CPC Classifications
H; H01; H01J; H01J5/00; H01J5/20; H01J19/00; H01J19/28; H01J19/32; H01J19/34; H01J2893/00; H01J2893/0001; H01J2893/0002; H01J2893/0003; H01J2893/0033; H01J2893/0037
Claims Analysis
Total Claims: 0
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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) | 1958-10-17 | 1959-04-18 | 1959-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-17 | 1963-04-18 | 1963-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-17 | 1967-04-18 | 1967-10-18 | $7700.00 | Window Closed / Lapsed |