Patent US3521726A successfully refreshed from Google Patents.
US3521726A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-cooled internal combustion engine with sound-proofed sheathing
Assignee: Individual
•
Filing: 1969-03-21
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Granted: 1970-07-28
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Expires: 1989-03-21
Abstract
No abstract record available.
Inventors
- 👤 Fritz Freyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:32
CPC Classifications
F; F02; F02B; F02B77/00; F02B77/11; F02B77/13; F02M; F02M35/00; F02M35/12; F02M35/1277
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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 |