US2439109A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-heating furnace with selective
Assignee: —
•
Filing: —
•
Granted: 1948-04-06
•
Expires: 1965-04-06
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:53
CPC Classifications
—
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US46601A
Cited
US85564A
Cited
US152274A
Cited
US986538A
Cited
US1369069A
Cited
US1482112A
Cited
US1991449A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-04-06 | 1951-10-06 | 1952-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-04-06 | 1955-10-06 | 1956-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-04-06 | 1959-10-06 | 1960-04-06 | $7700.00 | Window Closed / Lapsed |