Patent US4835506A successfully refreshed from Google Patents.
US4835506A
Expired / Lapsed
US
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Hollow substantially hemispherical permanent magnet high-field flux source
Assignee: United States Department of the Army
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Filing: 1988-05-27
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Granted: 1989-05-30
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Expires: 2008-05-27
Abstract
Abstract A hollow hemispherical flux source produces a uniform high-field in its central cavity. The hemisphere is comprised of a selected magnetic material whose magnetization is azimuthally symmetrical. The magnetic orientation (α) in the hemispherical permanent magnet shell is given by the equation: α=2θ where θ is the polar angle. A planar plate of high saturation, high permeability material closes the open end of the hemisphere. An axial bore hole through the hemisphere and/or through the planar plate provides the requisite accessability.
Inventors
- 👤 Herbert A. Leupold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:30
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/383; H; H01; H01F; H01F7/00; H01F7/02; H01F7/0273; H01F7/0278; H01J; H01J23/00; H01J23/02; H01J23/08; H01J23/087
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
80 words
A permanent magnet structure comprising a hollow substantially hemispherical magnetic flux source for producing a substantially uniform high-field in its central cavity, said hemispherical flux source being azimuthally symmetrical in magnetization, the magnetic orientation (α) in the substantially hemispherical magnetic shell being given by the equation α=2θ, where θ is the polar angle, and a planar plate of high saturation, high permeability material upon which said hemispherical flux source is placed so that said plate closes the open end thereof.
Claim 2
Dependent Claim
80 words
A permanent magnet structure comprising a hollow substantially hemispherical magnetic flux source for producing a substantially uniform high-field in its central cavity, said hemispherical flux source being azimuthally symmetrical in magnetization, the magnetic orientation (α) in the substantially hemispherical magnetic shell being given by the equation α=2θ, where θ is the polar angle, and a planar plate of high saturation, high permeability material upon which said hemispherical flux source is placed so that said plate closes the open end thereof.
Claim 3
Dependent Claim
16 words
A permanent magnet structure as defined in claim 1 wherein said central cavity is substantially hemispherical.
Claim 4
Dependent Claim
19 words
A permanent magnet structure as defined in claim 2 wherein said planar plate has an axial bore hole therethrough.
Claim 5
Dependent Claim
31 words
A permanent magnet structure as defined in claim 3 wherein said hemispherical flux source has an axial bore hole therethrough which is aligned with the bore hole through said polar plate.
Claim 6
Dependent Claim
19 words
A permanent magnet structure as defined in claim 4 wherein said bore holes are of substantially the same diameter.
Claim 7
Dependent Claim
27 words
A permanent magnet structure as defined in claim 5 wherein said planar plate comprises a disc-shaped plate coextensive with the open end of said hemispherical flux source.
Claim 8
Dependent Claim
26 words
A permanent magnet structure as defined in claim 6 wherein said bore holes are of a diameter up to one-fourth the diameter of said central cavity.
Claim 9
Dependent Claim
38 words
A permanent magnet structure as defined in claim 7 wherein the substantially hemispherical magnetic shell is comprised of a plurality of juxtaposed conical sections, each conical section being segmented along a plurality of distinct lines of longitudinal meridians.
Claim 10
Dependent Claim
49 words
A permanent magnet structure as defined in claim 8 wherein the field (H) in said central cavity is given by: H=(4/3)B.sub.r ln(r.sub.o /r.sub.i) where B r is the remanence of the magnetic material and r o and r i are, respectively, the outer and inner radii of the hemisphere.
Claim 11
Dependent Claim
21 words
A permanent magnet structure as defined in claim 9 wherein said permeable plate is comprised of a selected soft ferromagnetic material.
Claim 12
Dependent Claim
27 words
A permanent magnet structure as defined in claim 10 wherein said substantially hemispherical flux source is in the form of a polyhedron having a multiplicity of facets.
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) | 1992-05-29 | 1992-11-28 | 1993-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-29 | 1996-11-28 | 1997-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-29 | 2000-11-28 | 2001-05-30 | $7700.00 | Window Closed / Lapsed |