Patent US2684122A successfully refreshed from Google Patents.
US2684122A
Expired / Lapsed
US
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Hellcopter rotor structure
Assignee: Individual
•
Filing: 1952-01-24
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Granted: 1954-07-20
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Expires: 1972-01-24
Abstract
No abstract record available.
Inventors
- 👤 John A Perry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:34
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/37; B64C27/41; B64C27/43
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1742665A
Cited
US2045355A
Cited
US2086802A
Cited
US2127105A
Cited
GB598878A
Cited
US2510006A
Cited
US2569061A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-07-19 | 1958-01-18 | 1958-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-07-19 | 1962-01-18 | 1962-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-07-19 | 1966-01-18 | 1966-07-20 | $7700.00 | Window Closed / Lapsed |