Abstract: A method of slitting selected plies of multiply paperboard blanks by compressing narrow portions against an anvil surface (preferably soft) and cutting one or more plies along the compressed portions. The apparatus includes a cutting rule (straight or annular) with compression rules on each side to compress the blanks simultaneously with the cutting. The method and apparatus may be used in conjunction with conventional flat-bed or rotary diecutting.

Abstract: Improved blank-stripping apparatus for rotary die cutters of the type which have a die cutting roll, and an anvil roll for supporting paperboard blanks against a cutting rule on the die cutting roll, includes a rotary-cam-timed valve system pressure-actuating one or more pneumatic piston and cylinder assemblies within or adjacent the cutting rule for ejecting scrap radially from the cutting rule in synchronism with rotation of the die cutting roll; after scrap ejection the valve system vents pressure so that contact with a succeeding paperboard blank and/or spring bias easily retracts the plunger to position for pneumatic actuation in the succeeding cycle of operation.

Abstract: A method and apparatus for detecting jam-ups of serially advancing blanks of which the method comprises storing a number corresponding to the length of the blanks in predetermined increments, detecting a leading edge of such blanks, actuating a control means by the detection of the leading edges which generates a digit corresponding to the predetermined increments, detecting a trailing edge of such blanks to deactuate the control means, comparing the stored number with the digits generated by the control means, and stopping the blanks when the number of digits exceeds the stored number.