US2623735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recirculating air heater
Assignee: E L SCHOFIELD Inc
•
Filing: 1948-12-16
•
Granted: 1952-12-30
•
Expires: 1968-12-16
Abstract
No abstract record available.
Inventors
- 👤 Earl L Schofield
- 👤 Bayard C Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:02
CPC Classifications
B; B60; B60H; B60H1/00; B60H1/00457; B60H1/00464
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
FR846879A
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US1928094A
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US2093057A
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US2221891A
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US2188388A
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US2087160A
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US2237477A
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US2249957A
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US2202920A
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US2261579A
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US2270823A
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US2277870A
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US2464473A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-12-30 | 1956-06-30 | 1956-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-12-30 | 1960-06-30 | 1960-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-12-30 | 1964-06-30 | 1964-12-30 | $7700.00 | Window Closed / Lapsed |