Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1999-05-17
2000-12-26
Hofsass, Jeffery A.
Communications: electrical
Condition responsive indicating system
Specific condition
3405681, 148310, G08B 1314
Patent
active
06166636&
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention is directed to a marker (also referred to as a tag) for use in a magnetic anti-theft security system, of the type having an oblong alarm-triggering strip composed of an amorphous ferromagnetic alloy, and at least one oblong activation strip applied on the alarm-triggering strip and composed of a semi-hard magnetic alloy.
DESCRIPTION OF THE PRIOR ART
Magnetic anti-theft security systems and markers are adequately known and described in detail in, for example, European Application 0 121 649, and PCT Application, WO 90/03 652. First, there are what are referred to as magneto-elastic systems wherein the activation strip serves of the activation of the alarm strip by magnetizing it; second, there are what are referred to as harmonic systems wherein the activation strip, after being magnetized, serves for the deactivation of the alarm strip.
The alloys with semi-hard magnetic properties that are employed for the pre-magnetization strips include Co--Fe--V alloys that are known, for example, as Vicalloy, Co--Fe--Ni alloys that are known, for example, as Vacozet, as well as Fe--Co--Cr alloys that are known, for example, as Crovac.
These alloys are applied parallel on the alarm strip either as individual sub-segments or as continuous strips.
For activation or, deactivation of the alarm strip, the sub-segments are then magnetized in one direction. For deactivation or, activation of a continuous activation strip, this is magnetized in alternating polarity.
In the magnetization of sub-segments in a direction, a significantly greater distance from the source of the external magnetic field than in the magnetization of a continuous activation strip can be employed due to the directional homogeneity. In the magnetization of a continuous activation strip, this must be brought very close to the source in order to be able to achieve the alternating magnetization. Only a contact activation and not a distance activation, accordingly, can be implemented with a continuous activation strip.
Since, however, there has been a move in the meantime to introduce the markers of the anti-theft security systems directly into the product to be protected (source tagging), the necessity arises of providing the alarm strips with activation strips that can also be magnetized from a greater distance or, with smaller fields. It has been shown that the coercive force of these activation strips must be limited to values of at most 60 A/cm.
The continuous activation strips known from the prior art, however, can only meet this requirement in an unsatisfactory way. In terms of process technology, however, the processing of continuous activation strips has considerable advantages over the application of sub-segments, since the activation strip can simply be applied parallel and durably on the alarm strip.
Given the employment of sub-segments, by contrast, these must either be pre-fabricated or directly applied in individual parts. A pre-fabrication causes higher costs. The application of sub-segments is accompanied by considerable problems in the exact geometrical allocation of the individual sub-segments on the alarm strip.
U.S. Pat. No. 3,820,104 discloses that continuous activation strips that are provided with holes be applied on the alarm strips. These holes simulate a sub-segment structure that allows a distance deactivation.
However, the geometrical allocation of the perforated activation strips on the alarm strips is accompanied by considerable problems. An exact allocation of alarm strip and perforated activation strip can only be guaranteed with a reproducibility of approximately +/-0.5 mm in width. Accordingly, a certain overlap of the holes with the alarm strip is needed, i.e. the diameter of the holes must approximately amount to the bandwidth of the alarm strip plus 1 mm, the bandwidth of the band must amount to this diameter plus a web width of at least 1 mm. This requires a greater use of material and, consequently, increased costs for materials.
SUMMARY OF THE INVENTION
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REFERENCES:
patent: 3820104 (1974-06-01), Fearon
patent: 3938125 (1976-02-01), Benassi
patent: 4510489 (1985-04-01), Anderson, III et al.
patent: 4536229 (1985-08-01), Jin et al.
patent: 4960651 (1990-10-01), Pettigrew et al.
patent: 5313192 (1994-05-01), Ho et al.
patent: 5539380 (1996-07-01), Hasegawa et al.
patent: 5653824 (1997-08-01), Manning et al.
Herget Matthias
Roth Ottmar
Hofsass Jeffery A.
Previl Daniel
Vacuumschmelze GmbH
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