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:
Jul. 23, 1991
Filed:
Apr. 11, 1989
Shinichi Inoue, Kobe, JP;
Kazuo Nakayama, Akashi, JP;
Yamato Scale Company, Limited, Akashi, JP;
Abstract
A foreign matter detector includes an oscillator for generating an oscillating signal, a phase shifter connected to the oscillator and adapted to provide a phase shifted oscillating signal, and an electromagnetic transducer. The transducer includes an excitation coil connected to the oscillator and two interconnected detection coils magnetically coupled to the excitation coil and adapted to produce a differential signal therebetween when an object is passed through the transducer. The detector also includes a first detector adapted to produce a first detected analog signal corresponding to the component of the differential signal in phase with the oscillating signal and a second detector adapted to produce a second detected analog signal corresponding to the component of the differential signal in phase with the phase shifted oscillating signal. The detector further includes an analog to digital converter connected to the first and second detectors adapted for converting the first and second analog detected signals into first and second series of digital values, respectively, circuitry connected to the converter for weighting the digital values, and circuitry connected to the weighting circuitry for selecting a representative value for the object from each of the first and second series of the weighted digital values.