Patent ID: 6400451
Filing Date: 2002-06-04
Classification: G01B

Abstract:
A method for measuring alignment of a wheel of a vehicle, comprising:(a) projecting a first pair of light beams, which are in parallel to each other and separated by a predetermined distance, to a first area of side wall of a tire of said wheel or to flat surface detachably attached to said wheel; (b) receiving reflected light from said first projected pair of light beams incident on said side wall or said flat surface and forming images from said reflected light at an image-forming surface of a first photo-electric converting device at a first location, said first photo-electric converting device being at a fixed distance from said wheel in an approximately axial direction; (c) measuring a length of a first space between said images formed on said first photo-electric converting device; (d) calculating a first distance to a first point on said side wall or said flat surface between the points of incidence of said first pair of light beams on said side wall or to said flat detector plate from said first photo-electric converting device, using said length of said first space; (a2) projecting a second pair of light beams, which are in parallel to each other and separated by a predetermined distance, to a second area of said side wall of a tire of said wheel or to said flat surface detachably attached to said wheel; (b2) receiving reflected light from said second projected pair of light beams incident on said side wall or said flat surface and forming images from said reflected light at an image-forming surface of a second photo-electric converting device at a second location, said second imaging device being at a fixed distance from said wheel in an approximately axial direction; (c2) measuring a length of a second space between said images formed on said second photo-electric converting device; (d2) calculating a second distance to a second point on said side wall or said flat surface between the points of incidence of said second pair of light beams on said side wall or said flat surface from said second photo-electric converting device, using said length of said second space; and (e) calculating an angle of said wheel from said first and said second distances and said first and second locations of said first and said second photo-electric converting devices.