US2470560A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oppositely rotating propellers
Assignee: Individual
•
Filing: 1939-06-13
•
Granted: 1949-05-17
•
Expires: 1959-06-13
Abstract
No abstract record available.
Inventors
- 👤 Walter S Hoover
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:40
CPC Classifications
B; B64; B64C; B64C11/00; B64C11/30; B64C11/306
Claims Analysis
Total Claims: 0
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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) | 1952-05-16 | 1952-11-15 | 1953-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-05-16 | 1956-11-15 | 1957-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-05-16 | 1960-11-15 | 1961-05-17 | $7700.00 | Window Closed / Lapsed |