US1662739A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of heat treatment of alumina and other materials
Assignee: Pacific Southwest Trust & Savi
•
Filing: 1925-04-07
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Granted: 1928-03-13
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Expires: 1945-04-07
Abstract
No abstract record available.
Inventors
- 👤 Thomas S Curtis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:47
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/021; C01F7/027
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) | 1931-03-13 | 1931-09-12 | 1932-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1935-03-13 | 1935-09-12 | 1936-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1939-03-13 | 1939-09-12 | 1940-03-13 | $7700.00 | Window Closed / Lapsed |