US4779314A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic fastener
Assignee: Application Art Laboratories Co Ltd
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Filing: 1987-07-01
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Granted: 1988-10-25
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Expires: 2007-07-01
Abstract
Abstract A magnetic fastener which substantially excludes external leakage of magnetic flux therefrom. The magnetic fastener has a fixed element and a movable element. The fixed element includes a permanent magnet plate, upper and lower iron plates located on upper and lower faces of the permanent magnet plate, and an iron bar erected uprightly on the lower iron plate. The upper iron plate has an upper face flush with an upper end face of the iron bar to form a magnetic attracting face. The fixed element further includes a magnetic shield plate located above the upper iron plate around the magnetic attracting face with a magnetic gap interposed therebetween. The magnetic shield plate has a cylindrical portion which covers outer peripheries of the upper iron plate and the permanent magnet plate and contacts with an outer peripheral edge of the lower iron plate.
Inventors
- 👤 Yoshihiro Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:35
CPC Classifications
A; A41; A41F; A41F1/00; A41F1/002; A45; A45C; A45C13/00; A45C13/10; A45C13/1069; Y; Y10; Y10T; Y10T24/00; Y10T24/32
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
214 words
A magnetic fastener, comprising a fixed element including a permanent magnet plate magnetized so as to present the magnetic poles adjacent upper and lower faces thereof, a pair of ferromagnetic plates located adjacent the upper and lower faces of said permanent magnet plate, and a ferromagnetic bar erected uprightly on that one of said ferromagnetic plates which is located adjacent the lower face of said permanent magnet plate, the other ferromagnetic plate adjacent the upper face of said permanent magnetic plate having an upper face flush with an upper end face of said ferromagnetic bar to form a magnetic attracting face, and a movable element including a ferromagnetic member for being removably attracted to said magnetic attracting face, said fixed element further including a magnetic shield plate located above a portion of the upper face of said the other ferromagnetic plate around said magnetic attracting face with a magnetic gap between said magnetic shield and said upper face, said magnetic shield plate having a cylindrical portion extending from an outer edge thereof, said cylindrical portion of said magnetic shield plate covering the outer peripheries of said other ferromagnetic plate and said permanent magnet plate and contacting an outer peripheral edge of the one ferromagnetic plate adjacent the lower face of said permanent magnet plate.
Claim 2
Dependent Claim
214 words
A magnetic fastener, comprising a fixed element including a permanent magnet plate magnetized so as to present the magnetic poles adjacent upper and lower faces thereof, a pair of ferromagnetic plates located adjacent the upper and lower faces of said permanent magnet plate, and a ferromagnetic bar erected uprightly on that one of said ferromagnetic plates which is located adjacent the lower face of said permanent magnet plate, the other ferromagnetic plate adjacent the upper face of said permanent magnetic plate having an upper face flush with an upper end face of said ferromagnetic bar to form a magnetic attracting face, and a movable element including a ferromagnetic member for being removably attracted to said magnetic attracting face, said fixed element further including a magnetic shield plate located above a portion of the upper face of said the other ferromagnetic plate around said magnetic attracting face with a magnetic gap between said magnetic shield and said upper face, said magnetic shield plate having a cylindrical portion extending from an outer edge thereof, said cylindrical portion of said magnetic shield plate covering the outer peripheries of said other ferromagnetic plate and said permanent magnet plate and contacting an outer peripheral edge of the one ferromagnetic plate adjacent the lower face of said permanent magnet plate.
Claim 3
Dependent Claim
20 words
A magnetic fastener according to claim 1, wherein said magnetic gap is constituted by a member of a non-magnetic material.
Claim 4
Dependent Claim
32 words
A magnetic fastener according to claim 1, further comprising a spacer interposed between said the other ferromagnetic plate and said permanent magnet plate within said cylindrical portion of said magnetic shield plate.
Claim 5
Dependent Claim
23 words
A magnetic fastener according to claim 1, wherein said ferromagnetic bar is erected uprightly at a central portion of said one ferromagnetic plate.
Claim 6
Dependent Claim
24 words
A magnetic fastener according to claim 1, further comprising a cover covering the portion of said other ferromagnetic plate around said magnetic attracting face.
Claim 7
Dependent Claim
22 words
A magnetic fastener according to claim 5, wherein a portion of said cover which contacts said movable element has a funnel-like shape.
Claim 8
Dependent Claim
18 words
A magnetic fastener as claimed in claim 2, wherein said magnetic gap is constituted by an air gap.
Claim 9
Dependent Claim
24 words
A magnetic fastener as claimed in claim 4, wherein said ferromagnetic bar is erected uprightly at a side portion of said one ferromagnetic plate.
References Cited (Backward Citations)
DE1068149B
Cited
US1198227A
Cited
US2637887A
Cited
US2901278A
Cited
DE1127509B
Cited
US3041697A
Cited
US3141216A
Cited
US4021891A
Cited
US4021891B1
Cited
US4021891B2
Cited
JPS59119804A
Cited
JPS60210805A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |