Improvements in or relating to methods of and/or apparatus for punching holes in sheet metal.

摘要

A machine for punching holes (21) in sheet metal (10) has a punch roller (3) carrying a plurality of punches (4) and a back up roller (6) having a groove therein which has a bottom (14) at a predetermined depth in the back up roller (6). Its method of use is to run sheet metal (10) through the nip between the two rollers (3) and (6) so that the punches (4) punch out slugs (12) of metal so that a point (13) on each slug (12) bears against the bottom (14) of the groove which acts as a pivot point (13) on which the slug (12) pivots to cause the slug (12) to be completely freed from the parent metal (10) by the further action of the punch (4).