Patent ID: 7562609
Filing Date: 2009-07-21
Classification: B21D,Y10T

Abstract:
1. A through-hole forming machine for forming a through-hole in a circumferential wall of a tubular part of a work piece by a punch-out press, comprising: a die for holding the work piece, the die contacting an outer face of the circumferential wall of the tubular part at a prescribed position corresponding to the through-hole to be bored; an elevating block which is movable in a punch-out direction; a rod-shaped metal core having a free front end part, which is inserted into the tubular part of the work piece and moved in the punch-out direction, and a rear end part which is received by the elevating block which is located on an outer part of the tubular part of the work piece and moved in the punch-out direction; a punch for punching out the through-hole with the die, the punch being fixed to and projected from the free front end part of the metal core and being inserted into the tubular part together with the free front end part of the metal core, whereby the punch faces a part of an inner wall face of the tubular part where the through-hole will be formed; a press pin being inserted in the tubular part via a guide through-hole, which is formed in the circumferential wall of the work piece and which is located on the opposite side of the prescribed position, the press pin contacting a surface of the metal core, which is located on the opposite side of the punch; and a press plate mechanism for simultaneously pressing and moving the press pin and the elevating block which receives the metal core, for relatively pressing and moving the punch toward the die so as to drive the punch into an inner face of the circumferential wall by the metal core and bore the through-hole.