Patent US2384578A successfully refreshed from Google Patents.
US1520231A
Expired / Lapsed
US
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Heating system
Assignee: W L Fleisher & Co Inc
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Filing: 1922-10-27
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Granted: 1924-12-23
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Expires: 1942-10-27
Abstract
No abstract record available.
Inventors
- 👤 Walter L Fleisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:18
CPC Classifications
F; F24; F24D; F24D5/00; Y; Y10; Y10S; Y10S261/00; Y10S261/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1927-12-23 | 1928-06-23 | 1928-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1931-12-23 | 1932-06-23 | 1932-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1935-12-23 | 1936-06-23 | 1936-12-23 | $7700.00 | Window Closed / Lapsed |