PURPOSE: To make a breakage in the root of a tip part of a mandrel preventable, by attaching the mandrel to be inserted into an edge part to a holder via a buffer member, in case of cutting a steel sheet having a baggy edge.
CONSTITUTION: A steel sheet pole 1 having a baggy edge part 1A is placed on a lower cutter 2 clamped in a holder 3, and a tip part 4A of a mandrel 4 is inserted into the inside of the edge part 1A. The mandrel 4 is attached to the holder 3 by a pin 5 via a bush 7 made of erethane rubber or the like, and at the time of being cut by an upper cutter 6 going down, the mandrel 4 is pressed down against elasticity of the bush 7, while a lower surface of the tip part 4A comes into contact with an inner surface of the edge part 1A, and load at the time of cutting is dispersed so that any breakage is prevented from occurring. After cutting, mandrel 4 is restored to its original position owning to the elasticity of the bush 7, thus friction and any hitch at the time when the tip part 4A passes through the inside of the edge part are in no case entailed. As for a buffer material, this outer plate spring, a coil spring, etc., are used as well.
HAYASHI NOBUO
SHIBAZAKI TERUO
| JP60153717B |