Patent US2680156A successfully refreshed from Google Patents.
US2680156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head for perpendicular recording
Assignee: General Electric Co
•
Filing: 1951-06-09
•
Granted: 1954-06-01
•
Expires: 1971-06-09
Abstract
No abstract record available.
Inventors
- 👤 Thorensen Ragnar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:19
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/74; G11B5/02; G11B5/127; G11B5/1278; G11B5/17; G11B5/48
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
DE612450C
Cited
US2247847A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-05-31 | 1957-11-30 | 1958-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-05-31 | 1961-11-30 | 1962-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-05-31 | 1965-11-30 | 1966-06-01 | $7700.00 | Window Closed / Lapsed |