Patent ID: 6152812
Filing Date: 2000-11-28
Classification: B26F,B28D,Y10T

Abstract:
A punching machine having a punch body comprising:a hollow cylindrical punch holder having a first axial through hole on a top side of the punch body;a hollow punch having a second axial through hole on a bottom side of the punch body having a cylindrical cavity on a front end and a circumferential portion with a plurality of sand formed thereon surrounding an outer surface of the cylindrical cavity;an elastic member; anda knockout pin provided through the first axial through hole and the second axial through hole having one end urged against one end of the elastic member in the punch holder and the other end extended a predetermined distance from a bottom of the cylindrical cavity in a stored position;whereby as the circumferential portion of the punch is cutting through a glass surface, the knockout pin is urging against a portion of the glass until the portion is separated from the glass completely.