Patent ID: 6540451
Filing Date: 2003-04-01
Classification: B26D,B26F,Y10T

Abstract:
A hole punching apparatus comprising:a frame having surface for supporting a workpiece to be cut and a recess in said support surface; a blade having a tubular cutting edge and a cavity with a diameter, the blade having first and second ends with the cutting edge being at the first end of the blade, the blade being rectilinearly movable relative to the frame between a retracted position and a cutting position, the blade in said cutting position residing in the recess; a projection in said recess which moves into the blade cavity as the blade moves from the retracted position into the cutting position, wherein the diameter of the cavity decreases from the cutting edge up to a first predetermined axial distance from the cutting edge towards the second end of the blade and increases from the first predetermined distance towards the second end of the blade, wherein the projection extends into the cavity at least the predetermined axial distance from the cutting edge when said blades in the cutting position such that a cutout from said workplace is advanced past said decreased diameter portion of said cavity; and a drive for rotating the cutting edge around a first axis as the blade moves from the retracted position into the cutting position.