US2694656A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic impulse record member, magnetic material, and method of making magnetic material
Assignee: IIT Research Institute
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Filing: 1947-07-25
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Granted: 1954-11-16
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Expires: 1967-07-25
Abstract
No abstract record available.
Inventors
- 👤 Camras Marvin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:26
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; G11B5/70678; G11B5/70684; G11B5/70689; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
99 words
A FERROMAGNETIC IRON OXIDE MATERIAL ADAPTED TO FORM AN ELEMENT OF A MAGNETIC IMPULSE RECORD MEMBER, SAID MATERIAL CONSISTING ESSENTIALLY OF ACICULAR CRYSTALLINE PARTICLES UNIFORMLY SMALL IN SIZE AND NOT OVER 6 MICRONS IN THEIR GREATEST DIMENSION OF A SYNTHETIC MAGNETIC OXIDE OF IRON SELECTED FROM THE GROUP CONSISTING OF MAGNETIC FERROSOFERRIC OXIDE, FE3O4, AND MAGNETIC GAMMA FERRIC OXIDE, FE2O3, THE SELECTED SYNTHETIC MEGNETIC OXIDE OF IRON HAVING A CUBIC LATTICE STRUCTURE, AND SAID MATERIAL HAVING A COERCIVE FORCE VALUE OF BETWEEN 200 AND 550 OVERSTEDS AND A RATIO OF BFM/BR AT H=1000 OF NOT OVER 3 TO 1.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-11-15 | 1958-05-17 | 1958-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-11-15 | 1962-05-17 | 1962-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-11-15 | 1966-05-17 | 1966-11-16 | $7700.00 | Window Closed / Lapsed |