Patent US2920381A successfully refreshed from Google Patents.
US2920381A
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Assignee: AT&T Inc
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Filing: 1953-04-01
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Granted: 1960-01-12
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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 18:30
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.
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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) | 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 |