Punch press apparatus for perforating explosive sheets

摘要

A punch press apparatus for perforating explosive sheet material has a cutter plate containing multiple tubular cutters projecting below the plate. Each cutter contains a spring biased plunger for ejecting cutout sheet material from within the tubular cutter. The rearward end of each plunger projects above the cutter plate and contains a compression spring which returns the plunger to its original position after it has ejected the cutout material. A removable plunger protector plate is positioned above the cutter plate and a plunger ejector plate is located above the protector plate. The latter contains holes for receiving the projecting plunger ends so that the plungers are not depressed when the ejector plate is moved downward to press the protector plate onto the cutter plate to perforate the sheet material against an anvil. After the perforation operation, the protector plate is removed and the ejector plate is moved downward to depress the plungers which eject the cutout sheet material from the cutters. A guide plate containing holes for receiving the projecting tubular cutters and positioned below the cutter plate, is moved downward to strip the perforated sheet from the outer surface of the tubular cutters.