Patent US3521837A successfully refreshed from Google Patents.
US3521837A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Airfoil
Assignee: Individual
•
Filing: 1967-06-30
•
Granted: 1970-07-28
•
Expires: 1987-06-30
Abstract
No abstract record available.
Inventors
- 👤 Hermann Papst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:10
CPC Classifications
B; B64; B64C; B64C21/00; B64C21/02; B64C21/06; B64C2230/00; B64C2230/04; Y; Y02; Y02T; Y02T50/00; Y02T50/10; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49316; Y10T29/496
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3128973A
Cited
US2406920A
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US2742247A
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US2841344A
Cited
US2925231A
Cited
US3117751A
Cited
US3366352A
Cited
US3374971A
Cited
US3467348A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-27 | 1974-01-26 | 1974-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-27 | 1978-01-26 | 1978-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-27 | 1982-01-26 | 1982-07-28 | $7700.00 | Window Closed / Lapsed |