US3677947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent magnet
Assignee: Evonik Operations GmbH
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Filing: 1970-08-31
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Granted: 1972-07-18
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Expires: 1990-08-31
Abstract
Abstract A PERMANENT MAGNET COMPRISING MAGNETICALLY ANISOTROPIC PARTICLES WHICH ARE PREFERABLY ORIENTED AND THEN BONDED. THE POWDERS ARE COMPOSED OF AT LEAST TWO PARTICLE FRACTIONS OF DIFFERENT AVERAGE GRAINS SIZE, TO WIT (A) A FIRST FRACTION HAVING AN AVERAGE GRAIN SIZE IN THE RANGE OF ABOUT 50-250 UM., (B) A SECOND FRACTION HAVING AN AVERAGE GRAIN SIZE IN THE RANGE OF ABOUT 5-50 UM., AND (C) SAID MAGNET ALSO CONTAINING EITHER A THIRD FRACTION OF SUCH PARTICLES HAVING AN AVERAGE GRAIN SIZE OF ABOUT <15UM. OR AN INORGANIC OR ORGANIC BINDEDR, THE WEIGHT RATIO OF A:B:C BEING ABOUT 7:3:1.
Inventors
- 👤 Alden E Ray
- 👤 Karl Strnat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:03
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/06; Y; Y10; Y10S; Y10S264/00; Y10S264/58
Claims Analysis
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References Cited (Backward Citations)
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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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |