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. 20, 1999
Filed:
Sep. 29, 1997
Forrest H Ballinger, Grain Valley, MO (US);
Harmon Industries, Inc., Blue Springs, MO (US);
Abstract
A reliable and consistent electrical contact path between the rails of a section of railroad track established by the shunting effect of the wheels and axles of a train is ensured by applying time-spaced, short duration electrical pulses to the rails at a voltage level sufficient to overcome poor wheel/rail contact. Each of the pulses is produced by a generator that discharges a capacitor across the rails. The narrow pulse width inductively isolates the pulse generator and associated track section from adjacent stretches of track, and the spacing between pulses further avoids interference with other types of electrical track equipment. A detector responsive to the voltage on the rails disables the pulse generator when the received voltage exceeds a threshold and thus indicates that no train wheels are present in the track section. In a grade crossing warning system, once activated the pulse generator and detector assume the role of the island detection circuit and maintain the crossing warning.