Method and apparatus for measuring vehicle track alignment.

摘要

The invention relates to a simple method and apparatus for measuring vehicle track alignment (toe-in and toe-out). The vehicle front wheels (10) are each supported on a pair of spaced parallel support rollers (11) and a sensing roller (13) is arranged in contact with the tyre tread surface at the lowermost point of the tyre (12) and normal to the longitudinal axis of the vehicle, that is, normal to the true forward direction of the vehicle. The sensing roller (13) is able to move axially on its axis of rotation (axle) (16). The method comprises rotating each front wheel (10) separately through a limited angular rotation equivalent to a known forward displacement of the vehicle and measuring the axial displacement of the sensing roller (13). The forward displacement and axial displacement figures may then be used to compute toe-in or toe-out and the same procedure may then be performed on the other wheel. The apparatus includes a mounting structure which extends across the width of the vehicle and supports the support rollers on each side. The mounting structure is pivoted between the vehicle wheels such that the apparatus automatically aligns with the apparatus. Means for obtaining a differential reading of axial displacement of the sensing rollers is also disclosed.