Device for preventing a collision between a work holder and a tool in numerical control for a turret punch press

A device for preventing a collision between a work holder and a tool in numerical control equipment for a turret punch press, comprising:

• work holder region storing means for storing data representing a region occupied by the work holder in a mechanical coordinate system;
• tool post shape storing means for storing data representing the sizes of a plurality of tool posts of a turret or the sizes of tools received in the tool posts;
• punching inhibit region computing means for reading out the size of the tool post receiving the selected tool or the size of the selected tool from the tool post shape storing means at the time of tool selection, and for computing a punching inhibit region for the selected tool from the read-out information and the stored information of said work holder region storing means;
• punching inhibit region storing means for storing the punching inhibit region;
• and
• collision preventing means for checking whether the position of the selected tool is within the punching inhibit region or not immediately before the execution of a punch command, and for stopping the operation of the machine and generating an alarm signal if the position of the selected tool is within the punching inhibit region.