US2920381A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent magnets
Assignee: AT&T Inc
•
Filing: 1953-04-01
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Granted: 1960-01-12
•
Expires: 1973-04-01
Abstract
No abstract record available.
Inventors
- 👤 Richard M Bozorth
- 👤 Ethan A Nesbitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:24
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/02; H01F7/0205; H01F7/021; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9265; Y10S428/928; Y10S428/9335; Y10S428/934; Y10S428/935; Y10S74/00; Y10S74/04; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12632; Y10T428/12771; Y10T428/12861; Y10T428/12882; Y10T428/12903; Y10T428/12951; Y10T74/00; Y10T74/18; Y10T74/18056; Y10T74/18088
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
35 words
A COMPOSITE PERMANENT MAGNET HAVING A COERCIVE FORCE GREATER THAN 100 OERSTEDS, SAID MAGNET INCLUDING ALTERNATE LAYERS OF IRON AND OF COPPER, EACH OF SAID LAYERS BEING FROM 150 A. TO 250 A. IN THICKNESS.
Claim 2
Dependent Claim
35 words
A COMPOSITE PERMANENT MAGNET HAVING A COERCIVE FORCE GREATER THAN 100 OERSTEDS, SAID MAGNET INCLUDING ALTERNATE LAYERS OF IRON AND OF COPPER, EACH OF SAID LAYERS BEING FROM 150 A. TO 250 A. IN THICKNESS.
References Cited (Backward Citations)
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Cited
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Cited
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Cited
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Cited
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Cited
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Cited
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Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-01-11 | 1963-07-13 | 1964-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-11 | 1967-07-13 | 1968-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-11 | 1971-07-13 | 1972-01-12 | $7700.00 | Window Closed / Lapsed |