Programming system for machine tools or the like

A programming system for use in machine tools wherein a slide is reciprocable by a hydraulic motor which receives and discharges hydraulic fluid by way of a regulating valve on the slide. The valve has a spool which is reciprocable between two operative positions and a neutral position and has a radially extending follower which can be arrested by the projections of an indexible drum mounted adjacent to the path of the slide. The movements of the spool from its neutral position to a selected operative position (in which the motor receives fluid for moving the slide forwardly or rearwardly) are initiated by a control plunger secured to the follower and reciprocable in cylinder chambers of the housing in response to admission of pressurized control fluid by a four-way pilot valve. The follower moves against a first projection during forward movement of the slide to thereby return the spool from one operative position to neutral position, and against another projection during rearward movement of the slide to thereby return the spool from the other operative position to the neutral position. The nominal diameter of the plunger is a small fraction of the diameter of the spool.