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:
Dec. 27, 1977
Filed:
Dec. 09, 1976
Jerry P Huffman, Churchville, NY (US);
John P LaForest, Conesus, NY (US);
William A Petit, Rochester, NY (US);
James A Smith, Conesus, NY (US);
General Signal Corporation, Rochester, NY (US);
Abstract
Alternating current track circuits are provided for the several adjoining track sections of a stretch of railway track, each of the track circuits comprising an alternating current code transmitter and an alternating current code receiver connected to track rails at opposite ends of the associated section. Circuit apparatus including an alternating current line circuit extending along the stretch of railway track is provided for normally communicating alternating current from the line circuit through rails of the associated track sections, the alternating current being modulated at a selected rate code and current in any two adjoining track sections being of opposite instantaneous polarity for broken down joint protection. Phase sensing apparatus is provided at a receiving end of each track section including a comparator for comparing the rate code modulated alternating current communicated through the track rails with a steady reference source connected to the line circuit. A system including a flip-flop circuit and a low pass filter is provided for energizing a track relay only in response to a distinctive output of the comparator indicative of proper phase relationship of the current in the associated track section.