Abstract: A sheet stacker, particularly for corrugated paperboard container blanks, has a downwardly movable elevator for supporting stacked sheets, firing rollers for feeding successive sheets in a path above the elevator, and a stop for stopping each successively fed sheet above the elevator and enabling each stopped sheet to drop onto a stack being formed. A flexible cam, preferably a resiliently flexible loop, is rotatably mounted above the elevator. The flexible cam is intermittently rotated to move the cam out of the path of a sheet being fed to allow a leading portion of this fed sheet to pass under the flexible cam, then to bring the cam into contact with a rear portion of the fed sheet to urge this rear portion towards the stack, and then to bring the flexible cam to rest in kissing contact with the fed sheet when resting on top of the stack being formed. Tolerance variations in the sheet thickness can be accommodated by flexing of the cam.

Abstract: A printing apparatus has a plurality of ink rolls, particularly anilox rolls, for a single printing cylinder at any one of a number of similar and serially arranged printing stations, each station having one ink roll at a time being selected for use in cooperation with either a wipe roll assembly or a doctor blade assembly associated with each station. The various assemblies are surrounded by respective movable cover members which allow the assemblies to either print, or be washed or cleaned, at the same time that a similar printing or cleaning operation is taking place at an adjacent printing station. A movable subframe adjacent the main frame carries the ink rolls and their associated movable cover members as well as both the wipe roll assembly and the doctor blade assembly.

Abstract: A doctor blade head assembly, particularly for use in a flexographic printing press, has a head body pivoted to a support frame with an inflatable air tube disposed therebetween. The air tube extends along a channel having a bottom formed with spaced apart raised portions which cause the air tube to bulge out at these locations. In this way the air tube essentially only presses against the head body at these spaced apart locations, for example at the center and adjacent the ends, which reduces the tendency of the head body to bend along its length. This provides a more uniform ink film on the ink roll being inked by the doctor blade head assembly. End seal arrangements at the ends of the head body each include a resilient block seal and a resilient pad seal with which greased edge portions of the doctor blades slidably engage. The doctor blades overhang the ends of the ink roll, and an ink outlet passageway extends through each end seal arrangement independently of the seals.

Abstract: A printing apparatus has a printing cylinder rotatably supported by a main frame. A subassembly contains a plurality of anilox rolls rotatable about parallel spaced-apart axis with the subassembly being rotatable about an axis parallel to and between these spaced-apart axes. A locking arrangement secures the subassembly in selected positions whereby any selected one of the anilox rolls can be brought into an operative position for cooperating with the printing cylinder for printing. Alternative ink systems supply ink to the selected anilox roll when in the operative position. Preferably the subassembly is supported at its ends by gear casings which are adjustably rotatably mounted in a subframe which itself is pivotally mounted in the main frame. The ink rolls may be anilox rolls with different surface screens.

Abstract: A lead edge sheet feeder, particularly for corrugated paperboard sheets, has an endless belt transfer section downstream of a control gate. This endless belt is driven at constant speed and at least first and second vacuum boxes are disposed successively along the transfer belt. Both vacuum boxes are continuously connected to a vacuum source. Each vacuum box has an open face which has to be completely covered by the sheet being fed before that vacuum box is effective in drawing the sheet against the transfer belt. There may be a third vacuum box, and vent holes may be provided in a common partition between the third and second vacuum boxes. The feed section, upstream of the control gate, may have modes for long and short sheets, in the shorter sheet mode less length of sheet being contacted by a feed conveyor.

Abstract: A method of testing a resiliently covered roll for surface flat spots involves rotating the roll and applying a film of water with a sponge roller to at least a portion of the length of the rotating roll surface. Then doctoring the rotating surface with a blade to remove the film, and detecting any flat spot by observing any puddle of water remaining after the doctoring. A testing device preferably is handheld and comprises a forwardly extending doctor blade below which is rotatably mounted the sponge roller. A rubber wipe roll for flexographic printing can be so advantageously tested for flat spots before installation.

Abstract: A printing apparatus includes a rotatable anilox roll engageable with a rotatable print cylinder for transferring ink thereto. A rotatable wipe roll and a doctor blade head are selectively engageable with different portions of the anilox roll to provide alternative wipe roll and doctor blade inking systems. Preferably both inking systems have substantially common ink supply and ink return paths with a valve being selectively operable to direct the ink supply path to either the wipe roll or the doctor blade head. Facilities for effecting a wash cycle may be provided to wash either inking system after use. Preferably an interlock arrangement prevents changing in use between the two inking systems until a wash cycle has been completed.

Abstract: A machine or machine section for squaring folded container blanks has a conveyor for conveying slotted and partially folded container blanks. A folding device completes folding of each container blank while being conveyed by the conveyor. A gauge plate is inserted in a slot in each of the slotted and partially folded container blanks. A mechanism moves the gauge plate in timed sequence with the conveyor, inserts the gauge plate in the slot before completion of folding of the respective blank in order to "square" the folded blank, and then withdraws the gauge plate from the slot. Overlapping flaps of each folded blank may be tacked together during "squaring" by drops of hot melt adhesive which subsequently hold the flat folded blanks square while the conventional slow drying water soluble glue dries. The "squaring" arrangement may be incorporated in a conventional gluer/folder machine.

Abstract: Apparatus, for example for processing sheets of corrugated paperboard in the production of container blanks, has a pair of feed rolls between which the sheets are fed while passing through the apparatus, and a pair of side frames in which the feed rolls are rotatably mounted one above the other. The upper of the feed rolls is journalled in bearings mounted eccentrically in bearing housings rotatable in holes in the side frames. Gearing is provided for adjustably rotating the bearing housings in the holes to move the upper feed roll respectively away from and towards the lower of the feed rolls. A pair of wedges act upon each bearing housing and are disposed in a cavity in each side frame below and communicating with the respective bearing housing. The wedges are moved towards each other by a screw bolt and/or a fluid cylinder to pre-load the bearing housings upwards in their holes.

Abstract: A method and apparatus for mounting a die, particularly a rigid cutting die, on a die cylinder includes having a bubble along a seal on the die to bridge any gaps between the die and the die cylinder when the die is initially positioned on the die cylinder. This bubble seal enables a vacuum to be applied between the initially positioned die and the die cylinder to pull the die down against and into conformity with the surface of the die cylinder, at the same time flattening the bubble seal. A key at a trailing edge of the die locates in an axial keyway in the die cylinder to circumferentially position the die; a bolt is then inserted at a leading edge of the die to establish axial location. During operation the die is held in position by the vacuum. Beam sensors and light reflectors may be incorporated to sense when a wrong die is present and shut down the apparatus.

Abstract: Sheet feeding apparatus, particularly for feeding corrugated paperboard sheets to container blank processing machinery, has an indexing transmission for cyclically accelerating and decelerating belts or the like for frictionally engaging and feeding sheets from an end of a stack of sheets. A cam arrangement cyclically shifts the feed belts or the like relative to a stack support surface between an operative position for feeding and an inoperative position. The accelerating and decelerating cycle of the belts occurs twice per machine cycle. The cam arrangement preferably comprises a single lobe cam and a double lobe cam, either of which can be selectively chosen for shifting the belts. When feeding one sheet per machine cycle of the downstream machinery, the single lobe cam is employed to shift the belts into the operative mode only once per machine cycle.

Abstract: Apparatus for mounting a flexible printing plate comprises a printing cylinder having a surface upon which the printing plate is mountable, and a connection for applying subatmospheric pressure inside the cylinder. A plurality of valves selectively apply the subatmospheric pressure to the surface from inside the cylinder. These valves have depressable actuating members protrudable above the cylinder surface. Those actuating members contacted by the printing plate when applied to the cylinder surface are depressed thereby to effect application of subatmospheric pressure to beneath the printing plate to draw the plate against the cylinder. Preferably, grooves are provided in the cylinder surface for distribution of the subatmospheric pressure beneath the plate. Advantageously, the printing plate may have a thin, highly flexible and deformable fringe along its trailing edge to seal the surface grooves, at that location.

Abstract: A rotary die-cut apparatus, in which a die roll cooperates with a resiliently covered anvil roll for die-cutting carton blanks passed therebetween, incorporates a constant mesh gear train between the die roll and the anvil roll for providing an infinite hunting ratio between the rolls. This provides more uniform wear of the anvil roll cover and prolongs its effective life. Preferably, this gear train includes a harmonic drive having a wave generator cam rotatable by a trim motor. An arrangement for sensing changes in diameter of the anvil roll due to wear of its cover may provide an input for determining the speed of the trim motor. A resurfacing mechanism for removing the outer surface of the cover when worn may provide this input. A pulse generator is preferably incorporated in a controller of the trim motor for periodically making random changes in the speed of the trim motor.

Abstract: Apparatus and method for cutting an end portion of a carton blank, e.g. to form a stitch flap, employs a rotatably driven male cutting head cooperating with a rotatably driven female cutting head. The female cutting head has a peripheral cutting groove therein and an anvil surface adjacent one side of the groove. The male cutting head has a two edged slot cutting blade of predetermined arcuate length which enters the groove each revolution, and a knife which extends transversely away from the blade and engages the anvil surface each revolution. The blade has a scallop-like cut-out in the side adjacent the anvil surface. The cut-out modifies the blade to a single edged cutting blade for a small part of its length. Scrap portions produced from the carton blank by a slotting cut of the blade and a transverse cut of the knife are integrally connected together by a bridging piece enabled by this cut-out.

Abstract: Apparatus for mounting a flexible printing plate comprises a printing cylinder having a surface upon which the printing plate is mountable, and a connection for applying subatmospheric pressure inside the cylinder. A plurality of valves selectively apply the subatmospheric pressure to the surface from inside the cylinder. These valves have depressable actuating members protrudable above the cylinder surface. Those actuating members contacted by the printing plate when applied to the cylinder surface are depressed thereby to effect application of subatmospheric pressure to beneath the printing plate to draw the plate against the cylinder. Preferably, grooves are provided in the cylinder surface for distribution of the subatmospheric pressure beneath the plate. Advantageously, the printing plate may have a thin, highly flexible and deformable fringe along its trailing edge to seal the surface grooves, at that location.

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 and an apparatus for stacking serially advancing parallel streams of blanks, such as corrugated paperboard blanks, by serially advancing such parallel streams in which there are spaces between pairs of such blanks in each of the streams but no spaces between the blanks of the pairs, creating spaces between the blanks of each pair during advance, stopping the advance of the blanks one after the other, and guiding succeeding spaced blanks one on top of the other to form a stack of blanks from each stream.

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: Apparatus for stacking paperboard blanks including a timed conveyor utilizing vacuum pressure to hold the blanks by their leading edges beneath the conveyor and serially advance them against a backstop whereupon they are released by the vacuum to settle upon an elevator which lowers incrementally as a stack of blanks is formed thereon. When the stack is completed, interrupter tines move over the stack and under the conveyor to store oncoming blanks while the stack is discharged from the elevator after which is rises. As the tines withdraw, the stored blanks settle on the elevator and subsequent blanks form another stack. A counter is used to energize operation of the tines to form stacks of a predetermined number of blanks on the elevator. An inclined conveyor utilizing vacuum belts is used to feed the blanks into engagement with the timed conveyor.