Patent US2668220A successfully refreshed from Google Patents.
US2668220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric heating appliance
Assignee: Individual
•
Filing: 1952-06-10
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Granted: 1954-02-02
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Expires: 1972-06-10
Abstract
No abstract record available.
Inventors
- 👤 Spurr Edward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:59
CPC Classifications
F; F24; F24C; F24C7/00; F24C7/06; F24C7/062; F24C7/065
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1317883A
Cited
US1007125A
Cited
US1014161A
Cited
US1023475A
Cited
US1644911A
Cited
US1652686A
Cited
GB445853A
Cited
US2379820A
Cited
US2613308A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-02-01 | 1957-08-03 | 1958-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-02-01 | 1961-08-03 | 1962-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-02-01 | 1965-08-03 | 1966-02-02 | $7700.00 | Window Closed / Lapsed |