Patent US3649411A successfully refreshed from Google Patents.
US3687725A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording media
Assignee: JOB WERNER HARTMANN
•
Filing: 1970-06-05
•
Granted: 1972-08-29
•
Expires: 1990-06-05
Abstract
Abstract MAGNETIC RECORDING MEDIA COMPRISING A NON-MAGNETIC SUPPORT AND A MAGNETIC LAYER BASED ON MAGNETIC PIGMENT AND BINDER, WHEREIN THE MAGNETIC LAYER CONTAINS A MIXTURE OF A NON-MAGNETIZABLE POWDER OF A SILICATE HAVING SHEET STRUCTURE (MOHS'' HARDNESS LESS THAN 6), E.G. TALC, AND A NON-MAGNETIZABLE POWDER WITH CUBE-SHAPED TO SPHERICAL PARTICLES OF HARD OXIDES, CARBIDES OR NITRIDES OF ALUMINUM, BORON, SILICON AND/OR CHROMIUM, E.G. CORUNDUM.
Inventors
- 👤 Job-Werner Hartmann
- 👤 Hans Joerg Hartmann
- 👤 Georg Schnell
- 👤 Roland Falk
- 👤 Werner Balz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/252; Y10T428/256; Y10T428/257
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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |