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:
Sep. 05, 1978
Filed:
Feb. 15, 1977
Gerald L Larson, Battle Creek, MI (US);
Walter K O'Neil, Southfield, MI (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
The position or presence of a metallic object is detected by an electronic circuit which senses a shift in phase between a first cyclic signal and a second cyclic signal which shifts in phase in response to movement of the object. An oscillator produces the first cyclic signal which is used as the reference signal and as the excitation for a parallel resonant circuit which produces the second signal. The phase of the second signal is shifted in response to movement of a metal plate or a shorted coil in an electromagnetic field produced by an inductor in the resonant circuit. The degree of the phase shifts may be used to detect the position of an object in the electromagnetic field or rate of the phase shifts may be used to detect the velocity of an object. An exclusive-or gate senses the changes or differences in phase between the two cyclic signals and produces an output signal representative of the changes or differences in phase. The output signal of the detector may be used with a digital counter to produce a digital output or with a smoothing filter to provide an analog output.