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:
Mar. 03, 1987
Filed:
Sep. 17, 1985
John J Torre, Monroe, NY (US);
Allied Corporation, Morris Township, Morris County, NJ (US);
Abstract
An inductive magnetic field article surveillance system includes a generator for a first magnetic field. Articles to be monitored include a structure responsive to the first magnetic field for deriving a second inductive magnetic field having a predetermined frequency. An inductive magnetic field receiver responsive to the second magnetic field includes a receiver coil arrangement for deriving a signal that is a replica of variations of the second magnetic field. Processing circuitry responds to the receiver coil arrangement to derive an indication of the presence of the structure. The receiver coil arrangement includes first and second coils likely to have different responses to the second magnetic field. Only one of the first and second coils is connected to the processing circuitry at a time, as a function of which coil is supplying a signal at the predetermined frequency of the second field to the processing circuitry for at least a predetermined time interval.