US2856573A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Induction motors
Assignee: National Research Development Corp UK
•
Filing: 1954-12-20
•
Granted: 1958-10-14
•
Expires: 1974-12-20
Abstract
No abstract record available.
Inventors
- 👤 Williams Frederic Calland
- 👤 Laithwaite Eric Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:16
CPC Classifications
H; H02; H02K; H02K41/00; H02K41/02; H02K41/025; H02K17/00; H02K17/02; H02K17/30
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1559920A
Cited
US1514474A
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US1595550A
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US1855617A
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US1770775A
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US2047831A
Cited
US2372590A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-10-13 | 1962-04-14 | 1962-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-10-13 | 1966-04-14 | 1966-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-10-13 | 1970-04-14 | 1970-10-14 | $7700.00 | Window Closed / Lapsed |