Abstract: A sheet feeder for corrugated paperboard sheets utilizing timed intermittently rotatable belts against which either the top or bottom sheet, depending on the configuration chosen, of a stack is brought into contact to feed such sheet in synchronism with adjacent processing machinery and utilizing continuously applied negative atmospheric pressure to hold such sheet against the belts without the need for valving or otherwise breaking the suction pressure.

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: Apparatus for directing a flow of air between the bottom blank of a stack and a blank advancing beneath the stack, particularly for corrugated paperboard counter stacker machines, comprising an air supply means adjacent the trailing edge of the bottom blank adapted to direct the flow of air beneath the bottom blank and above the advancing blank to form a cushion of air therebetween for reducing sliding friction between such blanks.

Abstract: A sheet feeder for corrugated paperboard sheets utilizing timed intermittently rotatable belts against which either the top or bottom sheet, depending on the configuration chosen, of a stack is brought into contact to feed such sheet in synchronism with adjacent processing machinery and utilizing continuously applied negative atmospheric pressure to hold such sheet against the belts without the need for valving or otherwise breaking the suction pressure.

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: Rotary slitting apparatus for slitting paperboard material including a pair of coacting knife holders for mounting on parallel adjacent rotatable shafts, such holders having thin flexible annular slitting blades clamped thereon at a slight angle to a plane normal to the axis of the shafts so that the blades overlap slightly to provide scissors-action cutting of paperboard material passed between the heads.

Abstract: A method and apparatus for extending the useful life of resilient covers on anvil rolls of rotary die cutters by causing the die cutting rules to penetrate the covers at sequential incrementally small circumferentially spaced locations around the cover by adding to the speed of rotation of the anvil roll relative to the speed of the die holder roll. Lateral reciprocation of the anvil roll is translated to rotary motion by a gear and pivot lever arrangement, such rotary motion being added to the normal speed of the anvil roll.