US3539768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical space heating system
Assignee: Individual
•
Filing: 1967-03-09
•
Granted: 1970-11-10
•
Expires: 1987-03-09
Abstract
No abstract record available.
Inventors
- 👤 Paul Eisler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:56
CPC Classifications
F; F24; F24D; F24D13/00; F24D13/02; F24D13/022; F24D13/024; H; H05; H05B; H05B3/00; H05B3/20; H05B3/22; H05B3/26; Y; Y02; Y02B; Y02B30/00
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) | 1973-11-09 | 1974-05-11 | 1974-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-09 | 1978-05-11 | 1978-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-09 | 1982-05-11 | 1982-11-10 | $7700.00 | Window Closed / Lapsed |