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:
Aug. 07, 1990
Filed:
Sep. 02, 1988
Warren W Welcome, Tarzana, CA (US);
Daniel R Sparks, Temple City, CA (US);
Hamilton Standard Controls, Inc., Farmington, CT (US);
Abstract
A speed detector, for use with a tone wheel having metal teeth, employs two coils positioned in offset relation near the tone wheel for interacting with the tone wheel teeth and thus changing their respective inductances. The coils preferably include iron cores to enhance magnetic coupling. One coil is in a phase sense oscillator circuit and the other is an a tuned sensor network. The oscillator is coupled to, and drives, the tuned network. The change in coil inductances effects a phase shift of the resulting signals in the oscillator and the tuned network, the magnitude of that phase shift typically being double that for a comparable single coil system. The output signals of the oscillator and tuned network provide inputs to a phase condition detector which looks for a reversal in their phase sequence and uses such event to provide timing reference pulses for a final determination of speed in a known manner.