US1930388A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for hardening alloy steels
Assignee: Thos Firth & John Brown Ltd
•
Filing: 1932-01-28
•
Granted: 1933-10-10
•
Expires: 1952-01-28
Abstract
No abstract record available.
Inventors
- 👤 Hatfield William Herbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:03
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/02
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) | 1936-10-09 | 1937-04-10 | 1937-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1940-10-09 | 1941-04-10 | 1941-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1944-10-09 | 1945-04-10 | 1945-10-10 | $7700.00 | Window Closed / Lapsed |