Abstract: A numerically controlled apparatus wherein a tool can be returned by a high speed retrograding operation without damaging a chip of a tool or a work. The numerically controlled apparatus comprises a command executing block which decodes a working program for each of block commands and controls controlling driving of a tool to work a work. A retrograde command storage block extracts data necessary for the production of a retrograde block command from the working program and stores the extracted data therein. Upon reception of a retrograding signal, an escapement command producing block produces an escapement block command, and a retrograde block command producing means produces a retrograde block command. Then, an escapement/retrograde command execution controlling block causes the command executing block to execute the escapement block command and the retrograde block command.

Abstract: Apparatus for confirming the clamping conditions of a clamping device which is used to clamp workpieces of different sizes. Signals corresponding to the kind of workpiece being clamped are derived from the flow rate of pressurized fluid used to drive the actuator of the clamping device. These signals are used to confirm the clamping conditions and also the kind, and the presence or absence, of the workpiece.