US2693076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Free piston internal-combustion engine
Assignee: Individual
•
Filing: 1951-05-18
•
Granted: 1954-11-02
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Expires: 1971-05-18
Abstract
No abstract record available.
Inventors
- 👤 Daniel H Francis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:51
CPC Classifications
F; F02; F02B; F02B71/00; F02B47/00; F02B47/02; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
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) | 1957-11-01 | 1958-05-03 | 1958-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-11-01 | 1962-05-03 | 1962-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-11-01 | 1966-05-03 | 1966-11-02 | $7700.00 | Window Closed / Lapsed |