US1981679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Furnace control
Assignee: Individual
•
Filing: 1931-11-30
•
Granted: 1934-11-20
•
Expires: 1951-11-30
Abstract
No abstract record available.
Inventors
- 👤 Russell W Stem
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:05
CPC Classifications
F; F23; F23L; F23L13/00; F23N; F23N3/00; F23N3/04; Y; Y10; Y10S; Y10S236/00; Y10S236/19
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) | 1937-11-19 | 1938-05-21 | 1938-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1941-11-19 | 1942-05-21 | 1942-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1945-11-19 | 1946-05-21 | 1946-11-20 | $7700.00 | Window Closed / Lapsed |