Locking mechanism for indexing device

Claim 1

A locking arrangement that prevents rotation of an elongated spindle comprising: gear means mounted on said spindle, said gear means having a plurality of predeterminedly spaced-apart teeth with portions of each of said teeth lying in a first plane which is perpendicular to the longitudinal axis of the spindle; a rotatably mounted shaft having an axis of rotation which is in skewed relationship with said longitudinal axis of said spindle; and wedging means including an outer periphery, a rotation point, and spaced-apart opposing camming surfaces inclined toward convergence at said outer periphery, said wedging means mounted on said shaft for rotational displacement about said rotation point, with distances from said outer periphery to said rotation point varying with angular displacement of said wedging means, such that, as said shaft is rotated, said wedging means is interposed between adjacent teeth of said gear means with a component of movement directed toward said spindle such that said camming surfaces engage said teeth of said gear means with a wiping action so as to be wedged between said teeth to thereby lock said spindle in a zero backlash manner.