Abstract: A punch unit for a press die is provided for punching a hole in sheet metal. The punch unit includes a piercing punch provided with a sharp projection, a plunger for pressing the piercing punch, a cylinder for supporting the piercing punch and the plunger slidably in a punching direction, and a coil spring for retracting the piercing punch and the plunger. Also disclosed is a press die for punching a hole in sheet metal using the punch unit.
Abstract: A punch unit for a press die for punching a hole in sheet metal includes: a piercing punch provided with a sharp projection; a plunger for pressing the piercing punch; a cylinder for supporting the piercing punch and the plunger slidably in a punching direction; and a coil spring for retracting the piercing punch and the plunger. Also disclosed are a press die for punching a hole in sheet metal and a punching method using the punch unit.
Abstract: A sheet metal punching apparatus 1 includes an upper die holder 2 which is raised and lowered by a hydraulic ram and the like; a pressing plate 3 secured to the upper die holder 2; a pressing pad 5 suspended from the upper die holder 2 through a resilient member 4; a punch holder 7 constructed as a punch unit secured to the pressing pad 5 by means of a bolt 6 and the like; a lower die 9 on which thin sheet metal 8 to be subjected to punching is placed; and a die 10 embedded in the lower die 9.
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