US2988896A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat pump defrost control
Assignee: Carrier Corp
•
Filing: 1957-02-01
•
Granted: 1961-06-20
•
Expires: 1977-02-01
Abstract
No abstract record available.
Inventors
- 👤 Jr Richard H Swart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:07
CPC Classifications
F; F25; F25B; F25B47/00; F25B47/02; F25B47/022; F25B47/025; F25D; F25D21/00; F25D21/002
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2531136A
Cited
US2666298A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-06-19 | 1964-12-19 | 1965-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-06-19 | 1968-12-19 | 1969-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-06-19 | 1972-12-19 | 1973-06-20 | $7700.00 | Window Closed / Lapsed |