US2643724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helicopter rotor
Assignee: RTX Corp
•
Filing: 1947-02-21
•
Granted: 1953-06-30
•
Expires: 1967-02-21
Abstract
No abstract record available.
Inventors
- 👤 Igor I Sikorsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:23
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/04; B64C27/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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GB423371A
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US2117788A
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GB467488A
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US2256918A
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US2393158A
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US2569061A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-29 | 1956-12-29 | 1957-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-29 | 1960-12-29 | 1961-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-29 | 1964-12-29 | 1965-06-30 | $7700.00 | Window Closed / Lapsed |