US2504320A
Expired / Lapsed
US
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Method of and apparatus for forced convection heating
Assignee: Lindberg Engineering Co
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Filing: 1945-02-26
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Granted: 1950-04-18
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Expires: 1965-02-26
Abstract
No abstract record available.
Inventors
- 👤 Slade B Gamble
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:32
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/74; C21D1/767; F; F27; F27D; F27D7/00
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) | 1953-04-17 | 1953-10-17 | 1954-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-04-17 | 1957-10-17 | 1958-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-04-17 | 1961-10-17 | 1962-04-18 | $7700.00 | Window Closed / Lapsed |