Punch press equipped with marking apparatus and method for marking by the punch press

A method of marking on work by means of a punch press, the punch press including:

• upper and lower turrets each formed with tool mounting sections for mounting punches or dies;
• a striker adapted to selectively strike one of the punches located at a working position;
• means for moving a work in X- and Y-directions relative to the working position;
• and
• a pneumatic marking tool removably mounted on the tool mounting section on the upper tool holder, the pneumatic marking tool including;
• a body formed with a cylinder chamber;
• a piston provided in the cylinder chamber for moving along a longitudinal axis of the cylinder chamber;
• a marking stylus provided in the body and operatively coupled to the piston;
• and
• a body being formed at its top portion with an inlet port for receiving compressed air and communicating with the cylinder chamber;
• wherein the striker is formed with a compressed air supply passage adapted to communicate with the inlet port of the marking tool when the striker is brought into contact with the top portion of the body,
• the method comprising the steps of:
• indexing the pneumatic marking tool at a predetermined working position;
• lowering the punching striker so that a lower end of the striker is brought into contact with the top portion of the pneumatic marking tool;
• supplying a compressed air from an air compressor to the pneumatic marking tool through the air passage formed in the striker, to move the marking stylus up and down;
• and
• moving work to be marked in two dimensional way in synchronism with motion of the marking stylus.