Patent US2755866A successfully refreshed from Google Patents.
US2755866A
Expired / Lapsed
US
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Tandem helicopter
Assignee: Individual
•
Filing: 1953-09-25
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Granted: 1956-07-24
•
Expires: 1973-09-25
Abstract
No abstract record available.
Inventors
- 👤 Apostolescu Stefan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:05
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/54; B64C27/58; B64C27/59; B64C27/605; B64C27/04; B64C27/08; B64C27/12; B64C27/16; B64C27/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2045623A
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US2273303A
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US2389798A
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US2432391A
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US2414435A
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US2437165A
Cited
US2640549A
Cited
US2663371A
Cited
US2638170A
Cited
US2472917A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-07-24 | 1960-01-23 | 1960-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-07-24 | 1964-01-23 | 1964-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-07-24 | 1968-01-23 | 1968-07-24 | $7700.00 | Window Closed / Lapsed |