Patent US2444781A successfully refreshed from Google Patents.
US2444781A
Expired / Lapsed
US
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Axial flow helicopter
Assignee: Individual
•
Filing: 1943-12-08
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Granted: 1948-07-06
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Expires: 1963-12-08
Abstract
No abstract record available.
Inventors
- 👤 Lloyd H Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:15
CPC Classifications
B; B64; B64C; B64C29/00; B64C29/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1191501A
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US1262660A
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US1686080A
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US2003206A
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US2022476A
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US2043704A
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US2142601A
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US2300268A
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US2328786A
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US2397357A
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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) | 1951-07-06 | 1952-01-05 | 1952-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-07-06 | 1956-01-05 | 1956-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-07-06 | 1960-01-05 | 1960-07-06 | $7700.00 | Window Closed / Lapsed |