Patent US3540809A successfully refreshed from Google Patents.
US3540809A
Expired / Lapsed
US
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Vibration damped helicopter rotor
Assignee: RTX Corp
•
Filing: 1968-09-20
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Granted: 1970-11-17
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Expires: 1988-09-20
Abstract
No abstract record available.
Inventors
- 👤 William F Paul
- 👤 Kenneth C Mard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:49
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/001; F; F16; F16F; F16F15/00; F16F15/10; F16F15/14; F16F15/1407; F16F15/145; Y; Y10; Y10S; Y10S416/00; Y10S416/50
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
FR773520A
Cited
US2280360A
Cited
US2343421A
Cited
US2348941A
Cited
US2480946A
Cited
DE1100498B
Cited
US3372758A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-11-16 | 1974-05-18 | 1974-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-16 | 1978-05-18 | 1978-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-16 | 1982-05-18 | 1982-11-17 | $7700.00 | Window Closed / Lapsed |