Patent US3781736A successfully refreshed from Google Patents.
US3781736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shield for permanent magnet structure
Assignee: General Electric Co
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Filing: 1972-10-26
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Granted: 1973-12-25
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Expires: 1992-10-26
Abstract
Abstract A shield or guide to reduce leakage flux in the vicinity of the air gap of a permanent magnet is provided by positioning magnetic sleeves or plates in engagement with surfaces of the permanent magnet adjacent the air gap. The sleeves or plates are polarized at their surfaces which engage the permanent magnet. Each sleeve or plate has its surface which abuts the permanent magnet of the same polarity as the portion of the permanent magnet which it engages. The sleeves or plates may be flexible. Ferrites and cobalt-rare earths are satisfactory magnetic materials for the sleeves and plates.
Inventors
- 👤 R Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:55
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/02; H01F7/0205; F; F25; F25B; F25B2321/00; F25B2321/002; F25B2321/0023
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
60 words
A magnetically shielded permanent magnet structure comprising: a permanent magnet having an air gap; and at least one flux guide of permanent magnet material outlying said magnet adjacent said air gap, said guide having magnetic poles oriented to provide counter magnetic potential directionally displaced 90* to the flux of said magnet whereby leakage flux at said air gap is reduced.
Claim 2
Dependent Claim
60 words
A magnetically shielded permanent magnet structure comprising: a permanent magnet having an air gap; and at least one flux guide of permanent magnet material outlying said magnet adjacent said air gap, said guide having magnetic poles oriented to provide counter magnetic potential directionally displaced 90* to the flux of said magnet whereby leakage flux at said air gap is reduced.
Claim 3
Dependent Claim
13 words
A structure as claimed in claim 1 wherein the shielding sleeve is flexible.
Claim 4
Dependent Claim
18 words
A structure as claimed in claim 1 wherein the shielding sleeve is composed of a cobalt-rare earth alloy.
Claim 5
Dependent Claim
18 words
A structure as claimed in claim 2 wherein the shielding sleeve is composed of a ferrite magnet material.
Claim 6
Dependent Claim
76 words
A magnetically shielded permanent magnet structure comprising: an elongated permanent magnet having an air gap; and a magnetic shield for reducing leakage flux at said air gap, said shield comprising flat magnets positioned around, and in contact with, said elongated magnet structure adjacent said air gap, said flat magnets being magnetized in a direction whereby the interior surfAce of each flat magnet possesses the same polarity as the portion of the elongated magnet which it engages.
Claim 7
Dependent Claim
76 words
A magnetically shielded permanent magnet structure comprising: an elongated permanent magnet having an air gap; and a magnetic shield for reducing leakage flux at said air gap, said shield comprising flat magnets positioned around, and in contact with, said elongated magnet structure adjacent said air gap, said flat magnets being magnetized in a direction whereby the interior surfAce of each flat magnet possesses the same polarity as the portion of the elongated magnet which it engages.
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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |