US3447335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable capacity centrifugal heat pump
Assignee: Individual
•
Filing: 1967-09-22
•
Granted: 1969-06-03
•
Expires: 1987-09-22
Abstract
No abstract record available.
Inventors
- 👤 John D Ruff
- 👤 Phillip R Wheeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:41
CPC Classifications
F; F25; F25B; F25B1/00; F25B1/10; F25B31/00; F25B31/006; F25B49/00; F25B49/02; F25B49/025; F25B2600/00; F25B2600/02; F25B2600/025; F25B2600/0253; Y; Y02; Y02B; Y02B30/00; Y02B30/70
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2718119A
Cited
US2786334A
Cited
US2963878A
Cited
US3094850A
Cited
US2964923A
Cited
US3163999A
Cited
US3218825A
Cited
US3143864A
Cited
US3280576A
Cited
US3378062A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-06-02 | 1972-12-02 | 1973-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-06-02 | 1976-12-02 | 1977-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-06-02 | 1980-12-02 | 1981-06-03 | $7700.00 | Window Closed / Lapsed |