Patent ID: 6792828
Filing Date: 2004-09-21
Classification: B21D,B29D,B60C

Abstract:
A method for making a press die for molding a sipe blade, said press die comprising a pair of divided parts between which a material for the sipe blade is interposed and pressed to mold the sipe blade into a desired shape, said method comprising the steps of:forming first a pattern mold for each said pair of divided parts having a shape that is the reverse of the shape of a respective one of said pair of divided parts; and forming a metal casting from each said pattern mold, each said metal casting having a shape that is the reverse of the shape of a respective one of said pattern molds; wherein each said pattern mold includes a first portion that corresponds to a first portion of said metal casting to which a load is applied by molding pressure in contact with the material for the sipe blade, said first portion of said metal casting having a shape corresponding to the desired shape of the sipe blade; and wherein each said pattern mold includes a second portion that corresponds to a second portion of said metal casting to which a load is not applied by molding pressure, and wherein said second portion of said pattern mold includes a first relief portion that does not correspond to the desired shape of the sipe blade and that does not substantially contact the sipe blade.