Patent US2133267A successfully refreshed from Google Patents.
US2133267A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Black oxide of iron and process for making the same
Assignee: C K Williams & Co
•
Filing: 1934-01-24
•
Granted: 1938-10-18
•
Expires: 1954-01-24
Abstract
No abstract record available.
Inventors
- 👤 Joseph W Ayers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:45
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/02; C01G49/08; C01P; C01P2006/00; C01P2006/60; Y; Y10; Y10S; Y10S423/00; Y10S423/01
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1941-10-17 | 1942-04-18 | 1942-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1945-10-17 | 1946-04-18 | 1946-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1949-10-17 | 1950-04-18 | 1950-10-18 | $7700.00 | Window Closed / Lapsed |