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US2986904A
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US
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Heat pump space heating system
Assignee: Individual
•
Filing: 1959-09-04
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Granted: 1961-06-06
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Expires: 1979-09-04
Abstract
No abstract record available.
Inventors
- 👤 Carl C Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:59
CPC Classifications
F; F24; F24D; F24D11/00; F24D11/02; F24D11/0257; F24D11/0278; F24D11/0285; F24F; F24F3/00; F24F3/001; F24S; F24S20/00; F24S20/40; F25; F25B; F25B13/00; F25B30/00; F25B30/02; F24S20/60; F24S20/67; Y; Y02; Y02B; Y02B10/00; Y02B10/20; Y02B10/70; Y02B30/00; Y02B30/13; Y02B30/52; Y02E; Y02E10/00; Y02E10/40
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-06-05 | 1964-12-05 | 1965-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-06-05 | 1968-12-05 | 1969-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-06-05 | 1972-12-05 | 1973-06-06 | $7700.00 | Window Closed / Lapsed |