Patent US2218711A successfully refreshed from Google Patents.
US2218711A
Expired / Lapsed
US
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Electrical switching device
Assignee: AT&T Inc
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Filing: 1938-12-30
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Granted: 1940-10-22
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Expires: 1958-12-30
Abstract
No abstract record available.
Inventors
- 👤 Francis A Hubbard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:39
CPC Classifications
H; H01; H01F; H01F29/00; H01F29/14; H01F29/146; H01F29/143; H03; H03K; H03K17/00; H03K17/51; H03K17/80; H03K17/82
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) | 1943-10-22 | 1944-04-22 | 1944-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-10-22 | 1948-04-22 | 1948-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-10-22 | 1952-04-22 | 1952-10-22 | $7700.00 | Window Closed / Lapsed |