Patent US4451811A successfully refreshed from Google Patents.
US4451811A
Expired / Lapsed
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Magnet structure
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1982-09-27
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Granted: 1984-05-29
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Expires: 2002-09-27
Abstract
Abstract A magnet for use in a bearing, such magnet preferably having a cylindrical bore to receive a shaft and ferrofluid between the shaft and the bore walls. The magnet is magnetized with its internal magnetization radially directed relative to the axis of the bore.
Inventors
- 👤 George J. Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:21
CPC Classifications
F; F16; F16C; F16C32/00; F16C32/06; F16C32/0629; F16C32/0633; F16C32/0637; F16C33/00; F16C33/02; F16C33/04; F16C33/06; F16C33/10; F16C33/1025; F16C33/103; F16C33/1035; F16C33/72; F16C33/74; F16C33/741; F16C33/743; F16C33/746
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
131 words
A permanent magnet comprising: a two-poled permanent magnet structure having a circularly cylindrical bore therethrough, the interior of said bore forming one of said poles, said bore having an axis of symmetry; said structure being divided circumferentially of said bore into a plurality of substantially contacting circumferential segments each having an inner surface which is a circumferential segment of the cylindrical surface of said bore; all of said segments being magnetized along their entire length and about the entire portions of said circumference with their internal magnetizations identically poled in a radical direction relative to said axis and their pole strengths to be substantially equal, to cause substantially the entire surface of said circumferential segments of said bore to become identically and substantially uniformly poled magnetic pole faces of said segments.
Claim 2
Dependent Claim
131 words
A permanent magnet comprising: a two-poled permanent magnet structure having a circularly cylindrical bore therethrough, the interior of said bore forming one of said poles, said bore having an axis of symmetry; said structure being divided circumferentially of said bore into a plurality of substantially contacting circumferential segments each having an inner surface which is a circumferential segment of the cylindrical surface of said bore; all of said segments being magnetized along their entire length and about the entire portions of said circumference with their internal magnetizations identically poled in a radical direction relative to said axis and their pole strengths to be substantially equal, to cause substantially the entire surface of said circumferential segments of said bore to become identically and substantially uniformly poled magnetic pole faces of said segments.
Claim 3
Dependent Claim
29 words
A permanent magnet as recited in claim 1 wherein said structure is divided between said segments substantially by planes defined by radii from said axis and by said axis.
Claim 4
Dependent Claim
20 words
A permanent magnet as recited in claim 1 wherein the outer surface of said magnet structure is substantially circularly cylindrical.
Claim 5
Dependent Claim
65 words
A permanent magnet as recited in claim 3 wherein said outer and inner surfaces are substantially concentric about said axis, and the internal magnetizations of said segments are identically poled and radial of said axis to cause said entire inner cylindrical surface of said structure to be a different polarity magnetic pole piece of said magnet than the magnetic polarity of said outer cylindrical surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-29 | 1987-11-28 | 1988-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-29 | 1991-11-28 | 1992-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-29 | 1995-11-28 | 1996-05-29 | $7700.00 | Window Closed / Lapsed |