US4829288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Economic, multi-directionally responsive marker for use in electronic article surveillance systems
Assignee: 3M Co
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Filing: 1987-11-30
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Granted: 1989-05-09
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Expires: 2007-11-30
Abstract
Abstract A magnetic marker for use with electronic article surveillance (EAS) systems in which a two-directional very high order harmonic response is obtained. The markers comprise two pairs of elongated strips of low coercive force, high permeability material positioned in a tic-tac-toe configuration such that the strips at right angles to an applied field of an EAS system collect and concentrate the lines of flux associated with the field into the strips parallel to the field, the concentrated flux being sufficient to result in a high harmonic response.
Inventors
- 👤 Clyde T. Eisenbeis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:23
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2408; G08B13/2411; G08B13/2428; G08B13/2437; G08B13/244; G08B13/2442
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
A marker for use in an electronic article surveillance system of the type in which an alternating magnetic field in an interrogation zone produces remotely detectable magnetization changes in the marker, wherein the marker comprises at least two pairs of strips of a high permeability, low coercive force, magnetic material, both pairs of strips being positioned in substantially the same plane, with the strips of each pair being positioned to be substantially parallel to each other and intersecting with the strips of the other pair and dimensioned so as to overlap and be magnetically coupled therewith, the extent of such overlap being such that less than 25% of the length of each strip extends beyond the side of an intersecting strip of another pair, the strips of a first pair thereby forming flux collectors to concentrate flux from fields extending substantially parallel to the strips of the second pair into the strips of the second pair.
Claim 2
Dependent Claim
156 words
A marker for use in an electronic article surveillance system of the type in which an alternating magnetic field in an interrogation zone produces remotely detectable magnetization changes in the marker, wherein the marker comprises at least two pairs of strips of a high permeability, low coercive force, magnetic material, both pairs of strips being positioned in substantially the same plane, with the strips of each pair being positioned to be substantially parallel to each other and intersecting with the strips of the other pair and dimensioned so as to overlap and be magnetically coupled therewith, the extent of such overlap being such that less than 25% of the length of each strip extends beyond the side of an intersecting strip of another pair, the strips of a first pair thereby forming flux collectors to concentrate flux from fields extending substantially parallel to the strips of the second pair into the strips of the second pair.
Claim 3
Dependent Claim
16 words
A marker according to claim 1, wherein all of said strips are substantially the same dimension.
Claim 4
Dependent Claim
16 words
A marker according to claim 1, wherein all of said strips are substantially the same composition.
Claim 5
Dependent Claim
41 words
A marker according to claim 1, further comprising at least one section of permanently magnetizable material positioned adjacent to each of said strips, and magnetically coupled thereto such that when so magnetized the detectable response resulting from the marker is altered.
Claim 6
Dependent Claim
21 words
A marker according to claim 4, wherein a piece of permanently magnetizable material is positioned over the intersections of said strips.
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) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |