Patent ID: 8578829

Claim:
A punching unit for punching holes through materials to be punched by engaging a punch with a die, comprising: an actuation pin fixed so as to protrude from the side of said punch; a cam member reciprocated in the direction orthogonal to the moving direction of said punch; a cam formed of a grooved hole that is formed through said cam member, engages with said actuation pin and has a V-shaped portion, one linear portion that extends from one end of the V-shaped portion and another linear portion that extends from another end of said V-shaped portion; and a fixing member with a guide hole formed therethrough, the guide hole having a predetermined shape to guide said actuation pin relative to said guide hole; wherein said guide hole has one end part having a width fitting with said actuation pin at positions corresponding to the linear portions of said cam and inclined surfaces extending to the both sides of the moving direction of said cam member from the one end part at positions corresponding to the V-shaped portion of said cam; and as said cam member moves, said actuation pin engages with the inclined surface of the V-shaped portion of said cam, thus moving said punch in its axial direction and at the punching position for punching a hole through the material to be punched, said actuation pin is guided by one of the inclined surfaces of said guide hole, turns said punch around its axial line and acts so as to reduce an inclined angle of the inclined surface of the cam that moves said punch in the axial direction.