Method and apparatus for target deactivation and reactivation in article surveillance systems
First Claim
1. A target deactivator for deactivating a target used in a magnetic type theft detection system, said target comprising a thin elongated strip of magnetically soft, high permeability and easily saturable magnetic material and having laminated thereto a deactivation element of magnetically hard, low permeability magnetic material, said target deactivator comprising a permanent magnet assembly made up of a plurality of permanent magnets lying in a flat plane with their poles arranged to form a line of spaced apart alternate north and south poles, support means for supporting said permanent magnet assembly and guide means for constraining relative movement between an object on which said target is mounted and said support means along a direction perpendicular to said flat plane while said target is maintained parallel to said plane.
3 Assignments
0 Petitions
Accused Products
Abstract
Targets (14) mounted on objects (12) for detection by a magnetic type theft detection system are deactivated in a target deactivator (26,64) which has magnet assembly (40,72) made up of spaced apart magnets with alternately opposed poles extending in a plane and guide walls (36, 38, 68, 70) extending perpendicular to the plane. Targets are reactivated by a reactivator (46, 76) having a magnet (52, 80) mounted thereon and arranged to be slid along the target.
50 Citations
13 Claims
- 1. A target deactivator for deactivating a target used in a magnetic type theft detection system, said target comprising a thin elongated strip of magnetically soft, high permeability and easily saturable magnetic material and having laminated thereto a deactivation element of magnetically hard, low permeability magnetic material, said target deactivator comprising a permanent magnet assembly made up of a plurality of permanent magnets lying in a flat plane with their poles arranged to form a line of spaced apart alternate north and south poles, support means for supporting said permanent magnet assembly and guide means for constraining relative movement between an object on which said target is mounted and said support means along a direction perpendicular to said flat plane while said target is maintained parallel to said plane.
- 5. A method of deactivating a target used in a magnetic type theft detection system, said target comprising a thin elongated strip of magnetically soft, high permeability and easily saturable material and having laminated thereto a deactivation element of magnetically hard, low permeability magnetic material, said method comprising the steps of maintaining along a flat plane, a pattern of spaced apart alternate magnetic fields and, while maintaining said target and plane parallel to each other, moving one toward the other until said magnetic fields cause the formation of corresponding magnetic poles in said deactivation element and thereafter separating said deactivation element and said plane along a direction perpendicular thereto until the deactivation element is outside the influence of the magnetic fields.
- 9. A target reactivator for reactivating elongated magnetic targets used in theft detection systems and which have been deactivated by a pattern of spaced apart alternate magnetic fields emanating from a deactivation element of magnetically hard low permeability material lying adjacent and extending continuously along the target and affixed with the target to an object being protected by the target, said reactivator comprising a magnet and a holder supporting said magnet, said holder having at least one guide projection which engages an edge of the object and permits the holder to be guided along said object in a direction along the length of the target with the poles of the magnet extending along the length of the target whereby the deactivation element becomes subjected to the field of said magnet and said pattern of spaced apart magnetic fields becomes erased by movement of said holder as it is guided along said object.
- 12. A method of reactivating an elongated magnetic target used in a theft detection system and which has been deactivated by a pattern of spaced apart alternate magnetic fields emanating from a deactivation element of magnetically hard low permeability material lying adjacent the target and affixed with the target to an object being protected by the target, said method comprising the steps of supporting a magnet in a holder having a guide projection, engaging said projection with an edge of the object parallel to the target, bringing the magnet into confronting relationship with the deactivation element and, while said projection is engaged with said edge of the object, moving said holder along said edge of the object to move said magnet along the target to erase the pattern of spaced apart alternate magnetic fields from said deactivation element.
Specification