US2693941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air heater
Assignee: Individual
•
Filing: 1951-04-12
•
Granted: 1954-11-09
•
Expires: 1971-04-12
Abstract
No abstract record available.
Inventors
- 👤 Sigfred O Bystrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:06
CPC Classifications
F; F24; F24B; F24B7/00; F24B7/005; B; B26; B26D; B26D7/00; B26D2007/0012; B26D2007/0068; Y; Y10; Y10S; Y10S165/00; Y10S165/228; Y10S165/302; Y10S165/901
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2108033A
Cited
US2311984A
Cited
US2414829A
Cited
US2421371A
Cited
GB622899A
Cited
US2575894A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-11-08 | 1958-05-10 | 1958-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-11-08 | 1962-05-10 | 1962-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-11-08 | 1966-05-10 | 1966-11-09 | $7700.00 | Window Closed / Lapsed |