System for monitoring the position of a machine component

A system for monitoring positions of a machine tool component which carries out feed motions toward a workpiece and return motions away from the workpiece and for coarsely controlling the feed and return motions, comprising:

• a hydraulic driving means for effecting the feed and return motions;
• monitoring means for electrically-controlled presetting of desired positional values for the component and mechanical feedback of actual positional values of the component;
• and
• a follow-up control apparatus operatively connected with the hydraulic driving means and the monitoring means, wherein valves are provided to be opened and closed to permit a pressure medium to be selectively delivered to the hydraulic driving means for moving the component in feed and return directions, valve actuating means for causing displacement of the valves in response to the preset desired values from a basic position in which the desired and actual positional values are the same to positions corresponding to the feed and return directions of the component, and proximity switch means having a deflectable actuating member for providing an output signal to said monitoring means, transmission means operatively coupled between said valve actuating means and said proximity switch means for transmitting displacements of said valve actuating means into deflections of the actuating member of said proximity switch means, the deflections being proportional to but larger than the displacements, said proximity switch means, when viewed in a direction of the deflection of the actuating member, is at a defined distance from a position occupied by the actuating member when said valve actuating means is in the basic position.