Patent US4339853A successfully refreshed from Google Patents.
US4339853A
Expired / Lapsed
US
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Magnetic decoupler
Assignee: Dexter Magnetic Technologies Inc
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Filing: 1980-03-04
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Granted: 1982-07-20
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Expires: 2000-03-04
Abstract
Abstract A magnetic decoupler for use with an antitheft device is disclosed. In one preferred embodiment, the decoupler includes a composite permanent magnet comprising an annular permanent magnet that may be of ceramic and a second, preferably disc-shaped permanent magnet, which is preferably more strongly magnetized than the annular magnet and which preferably comprises a rare earth element. The two magnets are coaxially aligned with but axially displaced from each other and are oriented with the opposite polarity so as to create a region of especially great magnetic flux in the bore of the annular magnet. A cover plate, preferably of cold-rolled steel, may be provided adjacent the face of the annular magnet that is remote from the second magnet to further concentrate the flux in the bore.
Inventors
- 👤 Henry Lipschitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:55
CPC Classifications
E; E05; E05B; E05B73/00; E05B73/0017; E05B73/0047; E05B73/0052; H; H01; H01F; H01F7/00; H01F7/02; H01F7/0205; Y; Y10; Y10T; Y10T24/00; Y10T24/39; Y10T24/3969; Y10T24/50; Y10T24/505; Y10T292/00; Y10T292/11; Y10T292/14; Y10T70/00; Y10T70/50; Y10T70/5004; Y10T70/70; Y10T70/7051; Y10T70/7057
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
215 words
A composite magnet, comprising: an annular, ceramic magnet having opposed substantially flat faces and a bore extending between said faces along a first axis, a first of said flat faces defining a first pole of said ceramic magnet having a first polarity, a second of said flat faces defining a second pole of said ceramic magnet having a second, opposite, polarity; a cylindrical rare earth magnet having opposite substantially flat faces and a central axis coaxial with said first axis, a first of said flat faces of said rare earth magnet defining a first pole of said rare earth magnet having said first polarity, the second of said flat faces of said rare earth magnet defining a second pole of said rare earth magnet having said second polarity; and means for orienting said magnets relative to one another such that said ceramic magnet serves to both focus and add to the flux lines of said rare earth magnet and such that said flux lines extend between said first flat face of said rare earth magnet and said second flat face of said ceramic magnet along a path which passes through said bore of said ceramic magnet in a direction substantially parallel to said first axis whereby a strong magnetic field is defined in said bore.
Claim 2
Dependent Claim
215 words
A composite magnet, comprising: an annular, ceramic magnet having opposed substantially flat faces and a bore extending between said faces along a first axis, a first of said flat faces defining a first pole of said ceramic magnet having a first polarity, a second of said flat faces defining a second pole of said ceramic magnet having a second, opposite, polarity; a cylindrical rare earth magnet having opposite substantially flat faces and a central axis coaxial with said first axis, a first of said flat faces of said rare earth magnet defining a first pole of said rare earth magnet having said first polarity, the second of said flat faces of said rare earth magnet defining a second pole of said rare earth magnet having said second polarity; and means for orienting said magnets relative to one another such that said ceramic magnet serves to both focus and add to the flux lines of said rare earth magnet and such that said flux lines extend between said first flat face of said rare earth magnet and said second flat face of said ceramic magnet along a path which passes through said bore of said ceramic magnet in a direction substantially parallel to said first axis whereby a strong magnetic field is defined in said bore.
Claim 3
Dependent Claim
25 words
The composite magnet of claim 1, wherein said orienting means includes a cover plate having a face adjacent said second face of said ceramic magnet.
Claim 4
Dependent Claim
15 words
The composite magnet of claim 2, wherein said cover plate is formed of cold-rolled steel.
Claim 5
Dependent Claim
15 words
The composite magnet of claim 1, wherein said rare earth magnet is formed of SmCo.
Claim 6
Dependent Claim
31 words
The composite magnet of claim 1, wherein said first flat face of said rare earth magnet and said first flat face of said ceramic magnet lie substantially in a common plane.
Claim 7
Dependent Claim
36 words
The composite magnet of claim 2, wherein said orienting means further includes a first base plate on which said rare earth magnet is disposed and means for coupling said first base plate to said cover plate.
Claim 8
Dependent Claim
32 words
The composite magnet of claim 6, further comprising a second base plate, said second base plate being annular and being disposed on said first base plate and surrounding said rare earth magnet.
Claim 9
Dependent Claim
17 words
The composite magnet of claim 7, wherein said ceramic magnet is disposed on said second base plate.
Claim 10
Dependent Claim
124 words
In combination, a composite magnet according to any one of claims 2-8 or 1 and an antitheft device comprising: a pin having a tapered shaft provided with at least one circumferential groove; a main body having a nipple and having a first bore in said main body and extending into the interior of said nipple, and said nipple being small enough to be received in said bore of said annular magnet; and gripping means housed in the interior of said nipple for securely engaging said groove in said shaft of said pin when said pin is inserted in said first bore, it being possible to disengage said gripping means from said groove only by inserting said nipple in said bore of said annular magnet.
References Cited (Backward Citations)
SU304634A1
Cited
US2269149A
Cited
US3164756A
Cited
DE1616054A1
Cited
US3858280A
Cited
US3947930A
Cited
US3911534A
Cited
US3974581A
Cited
US4012813A
Cited
US4000543A
Cited
US4104622A
Cited
SU675231A1
Cited
US4156302A
Cited
US4265002A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-19 | 1986-01-18 | 1986-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-19 | 1990-01-18 | 1990-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-19 | 1994-01-18 | 1994-07-20 | $7700.00 | Window Closed / Lapsed |