Patent ID: 6776019
Filing Date: 2004-08-17
Classification: B21C,B29C,B29K

Abstract:
An extrusion die for a hollow member, comprising:a male die for defining a plurality of hollow portions of said hollow member; and a female die for defining an outer peripheral portion of said hollow member, wherein said male die is provided with an annular base portion, a bridge portion bridging said annular base portion in a radial direction of said annular base portion, and a mandrel having a plurality of forming protrusions. wherein said bridge portion is provided with a mandrel holding slit formed in a fore-and-aft direction, wherein said mandrel includes a mandrel main portion divided into a plurality of divided members and a plurality of rigid pins each arranged in a fore-and-aft direction of said mandrel main portion, wherein said plurality of rigid pins are pinched by and between said divided members of said mandrel main portion with tip portions of said plurality of rigid pins protruding from a front end of said mandrel main portion, whereby said plurality of tip portions constitute said plurality of forming protrusions, and wherein said mandrel main portion is inserted into said mandrel holding slit of said bridge portion to be held therein.