Patent US1820939A successfully refreshed from Google Patents.
US1820939A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combustion
Assignee: —
•
Filing: —
•
Granted: 1931-09-01
•
Expires: 1948-09-01
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:01
CPC Classifications
F; F23; F23N; F23N1/00; F23N1/02; F23N1/025
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) | 1934-08-31 | 1935-03-02 | 1935-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1938-08-31 | 1939-03-02 | 1939-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1942-08-31 | 1943-03-02 | 1943-09-01 | $7700.00 | Window Closed / Lapsed |