Small magnet resensitizer apparatus for use with article surveillance systems
First Claim
1. An apparatus which in movement relative to an article, having affixed thereto a dual status anti-theft marker including at least one control element, demagnetizes the control element to change the status of the marker, the apparatus comprising:
- (a) a housing having a working surface; and
(b) an elongated section of permanent magnetic material that exhibits an alternating magnetic field having, after a most intense peak, a substantially constant percentage decrease within an exponential envelope with each field reversal along the working surface.
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Accused Products
Abstract
A demagnetization apparatus for use with magnetically based electronic article surveillance systems having a dual status anti-theft marker containing at least one demagnetizable control element which when demagnetized allows the marker to be detected by the system when the marker is present in an interrogation zone. The apparatus includes an elongated magnetic section contained within a housing which exhibits a succession of fields of alternate polarity and at least a portion of which exhibits exponentially decreasing intensities at the working surface of the housing along that portion of the section. The section and a cover plate are orientated such that the external fields near the working surface are sufficient in intensities to demagnetize the demagnetizable element of the marker positioned proximate thereto while being rapidly attenuated a short distance from the section.
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Citations
37 Claims
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1. An apparatus which in movement relative to an article, having affixed thereto a dual status anti-theft marker including at least one control element, demagnetizes the control element to change the status of the marker, the apparatus comprising:
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(a) a housing having a working surface; and (b) an elongated section of permanent magnetic material that exhibits an alternating magnetic field having, after a most intense peak, a substantially constant percentage decrease within an exponential envelope with each field reversal along the working surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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- 28. An array of permanently magnetized regions establishing an alternating magnetic field along the length of the array for use in an apparatus for demagnetizing a magnetic marker, the array comprising at least three permanently magnetized regions established by one or more discrete pieces of permanent magnetic material, each region having a net polarization vector wherein major component of the net polarization vector for demagnetizing is parallel to the plane of the array.
Specification