Disarmable magnetic anti-shoplifting marker
Patent 4652863 Issued on March 24, 1987. Estimated Expiration Date: 
July 10, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 10, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesAntitheft system Theft detection apparatus and target and method of making same Patent #: 4568921 InventorAssigneeApplicationNo. 06/758669 filed on 07/10/1985US Classes:340/551, Disturbance of magnetic field340/572.6Having "soft" magnetic element (e.g., Permalloy)ExaminersPrimary: Swann, III, Glen R.Attorney, Agent or FirmInternational ClassesG08B 13/24 (20060101)G06K 7/10 (20060101) Foreign Application Priority Data1983-11-11 SEAbstractTwo strips (ribbons of foil) are positioned underneath a label on an article. Upon purchase of the article a magnetizing means with two spaced apart magnets provided thereon is passed across the strips in the transverse direction of the latter. One of the strips is of a ferromagnetic hard material and then will be magnetized with a number of poles. The second (one of the strips is of a ferromagnetic soft material which possesses the property of generating harmonics in a magnetic field. In combination with a magnetized strip having more than two north and south poles the ferromagnetic soft material will, however, be magnetically saturated so that harmonics will not be generated.In a sensing zone including magnetic fields the ability of the strips to generate harmonics is detected. If such harmonics are generated, the alarm is activated.Field of SearchDisturbance of magnetic field | |
