Patent US2501720A successfully refreshed from Google Patents.
US2501720A
Expired / Lapsed
US
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Screw propeller
Assignee: Rotol Ltd
•
Filing: 1944-11-24
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Granted: 1950-03-28
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Expires: 1964-11-24
Abstract
No abstract record available.
Inventors
- 👤 Godden Thomas Edward
- 👤 Bishop John Leslie Hunthold
- 👤 Holberton Bernard Victor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:00
CPC Classifications
B; B63; B63H; B63H3/00; B63H3/06; B63H3/08; B63H3/081; B63H3/082
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
DE40904C
Cited
US1565767A
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US1829930A
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US1892187A
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US1972486A
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GB449407A
Cited
GB463737A
Cited
US2244770A
Cited
US2355039A
Cited
US2383082A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-03-27 | 1953-09-26 | 1954-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-03-27 | 1957-09-26 | 1958-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-03-27 | 1961-09-26 | 1962-03-28 | $7700.00 | Window Closed / Lapsed |