MONITORING DEVICE AND METHOD FOR MONITORING FRACTURE IN WORKING TOOL MOUNTED IN PUNCHING MACHINE TOOL

摘要

PROBLEM TO BE SOLVED: To provide a simple-structured monitoring device capable of reliably identifying fracture or cracks in a working tool mounted in a tool.SOLUTION: The monitoring device includes a monitoring cylinder 23 with a feeler piston 24. A boundary position in which a piston rod 25 is abutted against a working tool 33 is provided for the feeler piston 24. The monitoring cylinder 23 has a blow-off opening 31. The blow-off opening 31 is arranged such that it is connected with a first chamber 26 located between the feeler piston 24 and a first end 28 of the monitoring cylinder 23 when the feeler piston 24 is in a position, at the fracture of the working tool 33, closer to a second end 29 of the monitoring cylinder 23 than the boundary position, and that the connection with the first chamber 26 is blocked when the feeler piston 24 is in the boundary position, or farther away from the second end 29 than the boundary position when there is no fracture of the working tool 33 is present.