Patent US2998850A successfully refreshed from Google Patents.
US2998850A
Expired / Lapsed
US
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Helicopter control apparatus
Assignee: Individual
•
Filing: 1958-09-09
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Granted: 1961-09-05
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Expires: 1978-09-09
Abstract
No abstract record available.
Inventors
- 👤 Victor O Armstrong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:05
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/22; B64C27/30
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USRE18957E
Cited
US1909450A
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US1986709A
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US2082674A
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US2455866A
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US2625997A
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US2614637A
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US2892502A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-09-04 | 1965-03-06 | 1965-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-09-04 | 1969-03-06 | 1969-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-09-04 | 1973-03-06 | 1973-09-05 | $7700.00 | Window Closed / Lapsed |