Apparatus for testing rack teeth

Apparatus for testing rack teeth of a rack member for a rack and pinion vehicle steering gear, said apparatus comprising a support for mounting the rack member for longitudinal displacement, a helically toothed test pinion member having an axis, a carriage mounting the test pinion member for rotation about its axis and in driving engagement with the rack teeth, biasing means for applying a biasing force urging the test-pinion member into engagement with the rack teeth and for providing a predetermined spacing between the longitudinal axis of the rack member and the axis of the test pinion member, means for adjusting the biasing force of the biasing means at said predetermined spacing, drive means for effecting displacement of one of the rack and test pinion members to impart displacement to the other of the rack and test pinion members, first sensing means for sensing the displacement of one of the rack and test pinion members which results from successive and predetermined unit displacement of the other of the rack and test pinion members, second sensing means for sensing a variation from the predetermined spacing between the axes of the rack and pinion members which is caused by said unit displacements, the first and second sensing means providing respective output signals upon sensing the displacement of one of the rack and test pinion members and the variation from the predetermined spacing between the axes of the rack and test pinion members, respectively, from which output signals characteristics of the rack member under test can be compared with the standard characteristics acceptable for the rack member, the support for mounting the rack member comprising means for supporting the rack member for rolling motion about its longitudinal axis during its driving engagement with the test pinion member.