Patent US1521842A successfully refreshed from Google Patents.
US1521842A
Expired / Lapsed
US
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Internal-combustion motor
Assignee: SPRAGUE
•
Filing: 1921-09-24
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Granted: 1925-01-06
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Expires: 1941-09-24
Abstract
No abstract record available.
Inventors
- 👤 Sprague Willis Douglass
- 👤 Jacob G Elkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:58
CPC Classifications
F; F01; F01L; F01L7/00; F01L7/02; F01L7/021; F01L7/024
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1928-01-06 | 1928-07-07 | 1929-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-01-06 | 1932-07-07 | 1933-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-01-06 | 1936-07-07 | 1937-01-06 | $7700.00 | Window Closed / Lapsed |