The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1978
Filed:
Jul. 15, 1976
Samuel Montean, Blaine, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A widely accepted type of antipilferage system provides in an interrogation zone a magnetic field which periodically alternates at a predetermined frequency. Such systems further include means for detecting very high order harmonics of the predetermined frequency such as result from the presence within the zone of a marker having non-linear electrical or magnetic properties. In the present invention, such a marker includes an asymmetrically shaped piece or pieces of low-coercive force ferromagnetic material, including a center section and flux concentrator sections at opposite ends of the center section. Such a marker enables the protection of objects having a maximum dimension which is less than the length of prior art 'open-strip' markers.