Patent US2936971A successfully refreshed from Google Patents.
US2936971A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helicopter
Assignee: Individual
•
Filing: 1956-01-13
•
Granted: 1960-05-17
•
Expires: 1976-01-13
Abstract
No abstract record available.
Inventors
- 👤 Gene C Holmes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:38
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/04; B64C27/08; B64C27/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
FR411240A
Cited
US1042758A
Cited
US1836351A
Cited
DE749113C
Cited
DE658376C
Cited
US2130918A
Cited
FR1097804A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-05-17 | 1963-11-16 | 1964-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-05-17 | 1967-11-16 | 1968-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-05-17 | 1971-11-16 | 1972-05-17 | $7700.00 | Window Closed / Lapsed |