US3532949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Commutating electric currents
Assignee: National Research Development Corp UK
•
Filing: 1968-11-06
•
Granted: 1970-10-06
•
Expires: 1988-11-06
Abstract
No abstract record available.
Inventors
- 👤 Frederic Calland Williams
- 👤 George Francis Nix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:30
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/20; H02M1/22; H02K; H02K13/00; H02K13/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2610231A
Cited
DE872598C
Cited
US2884584A
Cited
US3118106A
Cited
US3453513A
Cited
US3437898A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-10-05 | 1974-04-06 | 1974-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-10-05 | 1978-04-06 | 1978-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-10-05 | 1982-04-06 | 1982-10-06 | $7700.00 | Window Closed / Lapsed |