US4818966A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic field generating device
Assignee: Proterial Ltd
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Filing: 1988-03-28
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Granted: 1989-04-04
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Expires: 2008-03-28
Abstract
Abstract A magnetic field-generating device includes a pair of permanent magnet components disposed in such a manner as to face each other with a gap formed therebetween, a yoke for magnetically coupling the pair of permanent magnet components, and pole pieces which are each fixed to a surface of a corresponding permanent magnet component that faces the gap. The magnetic field generating device is adpated to generate a magnetic field in the gap. Each of the pole pieces is made of a laminate of magnetic plates which laminated in a direction substantially perpendicular to the sides of the solid care portion.
Inventors
- 👤 Toshinobu Miyamoto
- 👤 Hideya Sakurai
- 👤 Hirofumi Takabayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:50
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/02; H01F7/0273; H01F7/0278; G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/383
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
136 words
In a magnetic field-generating device which includes a pair of permanent magnet components disposed in such a manner as to face each other with a gap formed therebetween, a yoke for magnetically coupling said pair of permanent magnet components, and pole pieces which are each fixed at one end surface to a surface of an associated permanent magnet component, an opposite end surface thereof facing said gap, said magnetic field-generating device being adapted to generate a magnetic field in said gap, the improvement wherein each pole piece is composed of a solid core portion which has outer sides, and an outer portion formed of a laminate of magnetic sheets and non-magnetic sheets positioned around said solid core portion, said laminate being laminated in a direction substantially perpendicular to the outer sides of said solid core portion.
Claim 2
Dependent Claim
136 words
In a magnetic field-generating device which includes a pair of permanent magnet components disposed in such a manner as to face each other with a gap formed therebetween, a yoke for magnetically coupling said pair of permanent magnet components, and pole pieces which are each fixed at one end surface to a surface of an associated permanent magnet component, an opposite end surface thereof facing said gap, said magnetic field-generating device being adapted to generate a magnetic field in said gap, the improvement wherein each pole piece is composed of a solid core portion which has outer sides, and an outer portion formed of a laminate of magnetic sheets and non-magnetic sheets positioned around said solid core portion, said laminate being laminated in a direction substantially perpendicular to the outer sides of said solid core portion.
Claim 3
Dependent Claim
17 words
A magnetic field-generating device according to claim 1, wherein each said pole piece has a disk-like shape.
Claim 4
Dependent Claim
40 words
A magnetic field-generating device according to claim 1, wherein each said pole piece has a disklike shape, and wherein the peripheral portion of the end surface of said pole piece that faces said gap is provided with an annular protrusion.
Claim 5
Dependent Claim
64 words
A magnetic field-generating device according to claim 1, wherein each said pole piece has a disklike shape, wherein the peripheral portion of the end surface of each said pole piece that faces said gap is provided with an annular protrusion, and wherein a central portion of the end surface of each said pole piece that faces said gap is provided with a convex protrusion.
Claim 6
Dependent Claim
45 words
A magnetic field-generating device according to claim 1, wherein the ratio of the outer diameter D B of each said solid core portion to the outer diameter D p of each said pole pieces, D B / D p , is between 0.2 and 0.95.
Claim 7
Dependent Claim
44 words
A magnetic field-generating device according to claim 1, wherein each of said pole pieces has a trapezoidal cross-section , such that the end surface thereof that faces said gap is smaller than the end surface thereof that abuts against the associated permanent magnetic component.
Claim 8
Dependent Claim
26 words
A magnetic field-generating device according to claim 1, wherein each of said permanent magnet components is an annular body having a through-hole at the center thereof.
Claim 9
Dependent Claim
37 words
A magnetic field-generating device according to claim 1, wherein the solid core portion of each pole piece is disc-shaped, and wherein said laminate includes a magnetic plate strip wound in layers around said disc-shaped solid core portion.
Claim 10
Dependent Claim
20 words
A magnetic field-generating device according to claim 8, including a non-magnetic sheet interposed between said layers of magnetic plate strip.
Claim 11
Dependent Claim
20 words
A magnetic field-generating device according to claim 9, wherein said magnetic plate strip constitutes at least 30% of said laminate.
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) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |