Patent US2457421A successfully refreshed from Google Patents.
US2457421A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic retainer
Assignee: Individual
•
Filing: 1947-03-10
•
Granted: 1948-12-28
•
Expires: 1967-03-10
Abstract
No abstract record available.
Inventors
- 👤 Charles W Warren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:41
CPC Classifications
B; B43; B43M; B43M99/00; B43M99/009; H; H01; H01F; H01F7/00; H01F7/02; H01F7/0231; H01F7/0252; Y; Y10; Y10S; Y10S206/00; Y10S206/818; Y10S211/00; Y10S211/01
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-12-28 | 1952-06-28 | 1952-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-12-28 | 1956-06-28 | 1956-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-12-28 | 1960-06-28 | 1960-12-28 | $7700.00 | Window Closed / Lapsed |