US1664225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vacuum electric tube device
Assignee: Metropolitan Vickers Electrical Co Ltd
•
Filing: 1924-09-27
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Granted: 1928-03-27
•
Expires: 1944-09-27
Abstract
No abstract record available.
Inventors
- 👤 Robinson Ernest Yeoman
- 👤 Brown Walter John
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:31
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; H03F1/54; H03F1/542
Claims Analysis
Total Claims: 0
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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) | 1931-03-27 | 1931-09-26 | 1932-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1935-03-27 | 1935-09-26 | 1936-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1939-03-27 | 1939-09-26 | 1940-03-27 | $7700.00 | Window Closed / Lapsed |