US2689614A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Jet-rotated helicopter or other rotor
Assignee: National Research Development Corp UK
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Filing: 1951-10-04
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Granted: 1954-09-21
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Expires: 1971-10-04
Abstract
No abstract record available.
Inventors
- 👤 Dudley B Spalding
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:13
CPC Classifications
F; F02; F02K; F02K7/00; F02K7/005; B; B64; B64C; B64C27/00; B64C27/04; B64C27/12; B64C27/16; B64C27/18; F02K7/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-09-20 | 1958-03-22 | 1958-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-09-20 | 1962-03-22 | 1962-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-09-20 | 1966-03-22 | 1966-09-21 | $7700.00 | Window Closed / Lapsed |