US6084498A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic decoupler
Assignee: Dexter Magnetic Technologies Inc
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Filing: 1999-04-07
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Granted: 2000-07-04
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Expires: 2019-04-07
Abstract
Abstract An improved magnetic decoupler with a magnetic field shape, strength and gradient optimized for releasing security tags, such as an antitheft device of the type described above. Due to the structure of the magnetic decoupler, it contains less ferrous material than prior art decouplers heretofore employed. Reduction in size of the magnetic decoupler, along with improved magnetic strength, derive from the magnet assembly including magnets arranged with orientations that increase axial magnetic field gradient by superposition of the magnetic fields of each magnet.
Inventors
- 👤 Richard E. Stelter
- 👤 David Choit
- 👤 Thomas J. Devaney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:31
CPC Classifications
E; E05; E05B; E05B73/00; E05B73/0017; H; H01; H01F; H01F7/00; H01F7/02; H01F7/0273; H01F7/0278; H01F7/04
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
113 words
A permanent magnet assembly, comprising: an annular shaped magnet, having an inner diameter that defines a cavity, the annular shaped magnet situated about a central axis and generating a first external magnetic field; a central polyhedral shaped magnet, coaxially aligned with the annular shaped magnet, the central magnet generating a second external magnetic field of opposite polarity to the first external magnetic field; a plurality of polyhedral shaped magnets that abut the central magnet and the annular shaped magnet, the plurality of magnets having a magnetic field orientation normal to the first and second external magnetic fields to form a magnetic circuit that generates an axially aligned external magnetic field in the cavity.
Claim 2
Dependent Claim
113 words
A permanent magnet assembly, comprising: an annular shaped magnet, having an inner diameter that defines a cavity, the annular shaped magnet situated about a central axis and generating a first external magnetic field; a central polyhedral shaped magnet, coaxially aligned with the annular shaped magnet, the central magnet generating a second external magnetic field of opposite polarity to the first external magnetic field; a plurality of polyhedral shaped magnets that abut the central magnet and the annular shaped magnet, the plurality of magnets having a magnetic field orientation normal to the first and second external magnetic fields to form a magnetic circuit that generates an axially aligned external magnetic field in the cavity.
Claim 3
Dependent Claim
27 words
The permanent magnet assembly of claim 1, wherein the central polyhedral shaped magnet, has an outside dimension that approximates the inner diameter of the annular shaped magnet.
Claim 4
Dependent Claim
20 words
The permanent magnet assembly of claim 2, further comprising a steel base upon which the plurality of magnets is situated.
Claim 5
Dependent Claim
28 words
The permanent magnet assembly of claim 3, further comprising a steel shell surrounding the annular magnet, the plurality of magnets, and the steel base to reduce fringing flux.
Claim 6
Dependent Claim
18 words
The permanent magnet assembly of claim 4, wherein the central polyhedral shaped magnet is a parallelepiped shaped magnet.
Claim 7
Dependent Claim
35 words
The permanent magnet assembly of claim 5, wherein each of the plurality of polyhedral shaped magnets is a parallelepiped shaped magnet such that the plurality of magnets abut the central magnet in a cruciform arrangement.
Claim 8
Dependent Claim
18 words
The permanent magnet assembly of claim 1, wherein the annular shaped magnet is a high coercivity permanent magnet.
Claim 9
Dependent Claim
20 words
The permanent magnet assembly of claim 7, wherein each of the plurality of magnets is a high coercivity permanent magnet.
Claim 10
Dependent Claim
17 words
The permanent magnet assembly of claim 8, wherein the central magnet is a high coercivity permanent magnet.
Claim 11
Dependent Claim
125 words
A magnet assembly, comprising: a first polyhedral shaped magnet centered about an axis, the first magnet generating an external magnetic field in the direction of the axis; at least two additional polyhedral shaped magnets radially aligned with the first magnet, each having a magnetic field orientation normal to the external magnetic field generated by the first magnet to form a magnetic circuit that generates an axially aligned external magnetic field; and an annular shaped magnet coaxially aligned with the first polyhedral shaped magnet, the annular shaped magnet having an inner diameter that defines a cavity centered about the axis, the annular shaped magnet generating in the cavity a second external magnetic field of opposite polarity to the external magnetic field generated by the first magnet.
Claim 12
Dependent Claim
125 words
A magnet assembly, comprising: a first polyhedral shaped magnet centered about an axis, the first magnet generating an external magnetic field in the direction of the axis; at least two additional polyhedral shaped magnets radially aligned with the first magnet, each having a magnetic field orientation normal to the external magnetic field generated by the first magnet to form a magnetic circuit that generates an axially aligned external magnetic field; and an annular shaped magnet coaxially aligned with the first polyhedral shaped magnet, the annular shaped magnet having an inner diameter that defines a cavity centered about the axis, the annular shaped magnet generating in the cavity a second external magnetic field of opposite polarity to the external magnetic field generated by the first magnet.
Claim 13
Dependent Claim
17 words
The magnet assembly of claim 10, further comprising a steel base upon which the magnets are situated.
Claim 14
Dependent Claim
27 words
The magnet assembly of claim 11, further comprising a steel shell surrounding the annular magnet, the pair of magnets and the steel base to reduce fringing flux.
Claim 15
Dependent Claim
17 words
The magnet assembly of claim 10, wherein the annular shaped magnet is a high coercivity permanent magnet.
Claim 16
Dependent Claim
18 words
The magnet assembly of claim 13, wherein the at least two additional magnets are high coercivity permanent magnets.
Claim 17
Dependent Claim
16 words
The magnet assembly of claim 14, wherein the first magnet is a high coercivity permanent magnet.
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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) | 2003-07-04 | 2004-01-03 | 2004-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-04 | 2008-01-03 | 2008-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-04 | 2012-01-03 | 2012-07-04 | $7700.00 | Window Closed / Lapsed |