Patent US2009438A successfully refreshed from Google Patents.
US1640524A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Means for detecting metal particles in nonmetallic material
Assignee: AT&T Inc
•
Filing: 1921-02-24
•
Granted: 1927-08-30
•
Expires: 1941-02-24
Abstract
No abstract record available.
Inventors
- 👤 Augustine Roy Wilbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:54
CPC Classifications
B; B07; B07C; B07C5/00; B07C5/34; B07C5/344
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) | 1930-08-29 | 1931-02-28 | 1931-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1934-08-29 | 1935-02-28 | 1935-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1938-08-29 | 1939-02-28 | 1939-08-30 | $7700.00 | Window Closed / Lapsed |