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:
Nov. 21, 1995
Filed:
Dec. 20, 1993
James P Chew, Jeannette, PA (US);
Robert E Hamilton, Girard, PA (US);
Union Switch & Signal Inc., Pittsburgh, PA (US);
Abstract
The present invention provides a generally contactless method and apparatus for producing a speed reference for a rail vehicle which amenable to retrofit applications. The invention utilizes a laser source to direct a laser beam on a portion of the wheel and axle assembly of the rail vehicle. In presently preferred embodiments, the laser beam is directed on a tread or flange section of the vehicle wheel. The laser beam is believed to excite the molecules on the surface of the wheel in such a way that magnetic susceptibility is significantly increased. The increased magnetic susceptibility facilitates encoding of a magnetic signal by a magnetic encoding head. This magnetic signal may then be received after further rotation of the wheel by an angularly displaced magnetic receiving head. Processing circuitry is electrically connected to the magnetic encoding head and the magnetic receiving head to derive the speed reference based on the angular velocity and dimensions of the wheel. An erasing head may also be provided to remove the magnetic signal after detection by the receiving head.