US2420564A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of producing ferrosilicon
Assignee: Individual
•
Filing: 1942-04-27
•
Granted: 1947-05-13
•
Expires: 1962-04-27
Abstract
No abstract record available.
Inventors
- 👤 Percy H Royster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:58
CPC Classifications
C; C21; C21B; C21B5/00; C21B5/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2238078A
Cited
US2280452A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-05-12 | 1950-11-11 | 1951-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-05-12 | 1954-11-11 | 1955-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-05-12 | 1958-11-11 | 1959-05-13 | $7700.00 | Window Closed / Lapsed |