Abstract: A rotary drying drum for a moving web includes a stationary heater drum positioned coaxially within the drying drum such that the drying drum rotates around the heater drum. The heater drum may be supplied with steam via a hollow drying drum shaft without the use of high pressure steam joints. Heat from the interior heater drum is transferred to the rotary drying drum wall by a thin layer of suitable heat exchange fluid confined to the annular space between the coaxial drum walls. A low melting point bismuth/lead/tin alloy is the preferred heat exchange fluid.

Abstract: A double backer for curing the web bonding adhesive and drying the corrugated paperboard web utilizes a web holddown apparatus for maintaining the web in intimate drying contact with the lower heating units which does not require the use of a driven holddown belt. The web is pulled through the double backer by a downstream vacuum conveyor section comprising a single belt or a series of transport belt sections to the upper surfaces of which a vacuum is applied. The vacuum drive belt may have portions which are unsupported between laterally spaced vacuum slots, supported on a reduced friction support surface, or supported by air bearings to reduce friction and drive power requirements.

Abstract: Corrugated paperboard box blanks are formed with corner fold lines defined by a colinear slit and score. The score deflects one slit edge of the liner out of the plane of the blank such that, when a subsequent lateral fold is made on the line, one slit edge tucks consistently under the other along the full length of the fold line. The resultant box blanks fold more squarely than prior art folded boxes with no significant loss in the compressive strength of the box.

Abstract: A single facer apparatus for the production of single face corrugated web includes a pressure roll having a flexible outer surface which is internally biased outwardly to provide the pressure nip for joining the liner and glued corrugated media. A pressure shoe inside the flexible roll is sized and shaped to maintain operative pressure nip contact with at least two corrugating roll flutes. This substantially reduces vibration and noise. The pressure roll is constructed with a substantially enlarged diameter with respect to the corrugating rolls, the single face web joined with a preliminary bond at the pressure nip is wrapped around a substantial portion of the pressure roll circumference downstream of the nip, and the roll is internally heated to cause gelatinization of the glue and to fix the adhesive bond.

Abstract: A system for feeding and slitting short length, long width sheets and particularly suitable for solid fiberboard materials, includes a dual acting rake-type sheet feeder, a sheet decurling apparatus, and a multi-head slitter, all of which are interconnected to maintain positive sheet control through the entire system with resultant highly accurate short width slit sheet portions.

Abstract: An apparatus for slitting a stack of folded corrugated paperboard boxes utilizes a thin slitting blade mounted for continuous movement through a slitting station and defining a vertical slitting plane. A stack supporting table straddles the slitting blade support a stack of boxes in a stand-by position above the blade. Adjustable upstream and downstream squaring devices are operative to square and center the stack in the cutting plane and a vertically reciprocable ram operates to move the stack and the supporting table downwardly past the blade against a table biasing force to slit the stack into two half-size stacks. The squaring device is operable to re-square the slit half-size stacks prior to conveyance out of the slitting station. The slitting run of the continuous blade operates in a rigid blade holder which is adjustable to compensate for blade wear and to maintain the cutting edge of the blade in a fixed plane.

Abstract: A method and apparatus is disclosed for constructing block-shaped units of corrugated sheet material that are easily banded because of the absence of any irregularities in the units, and the units are as close to being cube-shaped as is possible for a given set of parameters. The automated stacking system comprises a computer programmed to determine a set of solutions to optimize a unit by determining an optimal number of corrugated sheets per bundle, and an optimal number of bundles per tier, and an optimal number of tiers per unit based upon customer order parameters. The system is initially set up with machine parameters defining machine constraints and a set of algorithm parameters which comprise desirability weighting factors. The desirability weighting factors allow a customer to customize the system according to preferred operating criteria.

Abstract: A variable load ballast system for the double facer of a corrugator includes a number of rows of holddown belt engaging ballast members positioned in side-by-side relation transversely across the belt, with the rows extending over the full heating section of the double facer. Each of the rows is divided into a number of longitudinal segments, each of which segments is controlled by a vertical actuator to move the segment between a lower full load ballast position on the belt and an upper no load position off the belt. The rows may comprise a series of ballast rollers or a continuous flexible membrane and either embodiment provides the ability to vary the ballast load on the holddown belt longitudinally, laterally and in any pattern of symmetry or asymmetry to accommodate a wide range of operating conditions and problems typically arising in the operation of a double facer. Ballast system control based on monitored web moisture content and web temperature is disclosed.

Abstract: An adhesive or other viscous liquid applicator apparatus utilizes a cylindrical glue roll and a reverse acting notched metering or doctor blade which forms, from an initial liquid layer on the roll, a series of laterally spaced liquid beads of metered size. The beads are subsequently spread to form a liquid layer for transfer to a web or other surface moved into generally tangential contact with the roll. The beads are preferably spread by a flexible spreader blade, but may also be spread by operating the peripheral surface of the roll and the web or surface in contact therewith at different speeds. The notched doctor blade provides accurate metering with a mechanically simple apparatus and the formation of beads helps prevent premature drying of the liquid.

Abstract: The labyrinth path in the corrugating nip of a single facer is substantially reduced by utilizing a small diameter intermediate corrugating roll captured between a pair of larger diameter conventional corrugating rolls. The two large diameter rolls capture the smaller roll and prevent bending thereof under corrugating loads. The corrugator may be operated at high speeds without the adverse increase in labyrinth path and web tension characteristic of large diameter corrugating rolls.

Abstract: A system for continuously delivering sheets which are provided in successive discrete stacks includes a stack infeed conveyor which includes a cushioned upper holddown belt synchronized to operate with a lower supporting infeed conveyor and to provide stability to stacks of relatively short sheets. A continuous lift apparatus receives successive stacks from the infeed system and utilizes a dual lift apparatus to provide the continuous delivery of stacked sheets which are individually fed from the top of the continuously ascending stack.

Abstract: A downstacker for paperboard sheets includes a sheet speed reducing shingler positioned in the stacking station and forming a shingling nip with the top sheet of the continuously descending stack. The shingling nip is positioned to engage and nip the next following sheet simultaneously with engagement of the stacking station backstop by the preceding sheet, thereby obviating sheet marking by an overrunning nip roll. A false backstop is periodically interposed to define a stack separation level and create an offset in the stack which engages the end of a separating fork as the continuously forming stack descends to facilitate insertion of the fork supporting into the stack. The fork provides interim support for the upper stack portion which continues to form while the lower stack portion is rapidly discharged.

Abstract: A system providing wrinkle-free drying of a liquid zone coating applied to a paper web includes a surface of high thermal conductivity heated to a uniform temperature above the boiling point of the coating liquid and over which the web is drawn with the uncoated face in contact with the surface. A vacuum is also drawn through the surface to hold the web in intimate contact therewith during drying. The method and apparatus of the invention are applicable to unitary webs as well as composite webs such as corrugated paperboard.

Abstract: A system for controlling the rate of heat transfer between the heating surfaces and a corrugated web in a double backer includes an air flow system operable to selectively apply a vacuum to the underside of the web via chambers formed in the spaces between the heating units or to apply pressurized air to the chambers to cool and lift the web, as necessary. A complementary system controls bowing in the surfaces of the heating units by supporting the undersides of the heating units with columns which include a thermally responsive metal member having an known coefficient of thermal expansion. The metal members are selectively heated by heating elements responsive to sensed bowing of the heating units to eliminate or minimize such bowing.

Abstract: A double backer for curing the web bonding adhesive and drying the corrugated paperboard web utilizes a web holddown apparatus for maintaining the web in intimate drying contact with the lower heating units which does not require the use of a driven holddown belt. The holddown is provided instead by a series of parallel, flexible, closely spaced strips suspended above the web in the heating section and extending in the direction of web travel. By adjusting the supports to which the ends of the strips are attached, the portions of the lengths of the strips maintained in contact with the web may be varied. The holddown strips may be provided with strip supporting air bearings which also help dissipate moisture and heat. The web is pulled through the double backer by a downstream vacuum conveyor section comprising a series of transport belts to the upper surfaces of which a vacuum is applied and which may also be supported by air bearings to reduce friction and drive power requirements.

Abstract: A palletizing system adapted particularly to the formation of stacks of rectangular prismatic shaped articles utilizes a conventional vertical stacking station which is uniquely supplied with tiers of articles alternately formed on and deposited from opposite sides of the stacking station. Virtually continuous tier and stack formation is possible and common control routines may be utilized to form tiers from multiple rows of articles.

Abstract: A hot plate for a double facer used in the manufacture of corrugated paperboard includes a substantially all copper construction which enhances thermal conductivity and heat transfer efficiency. Steam for heating the plates is provided through an array of copper tubes extending between manifolds on opposite sides of the hot plate, all in a manner which obviates the need for heavy pressure vessel construction. The hot plate is allowed to float on its supporting frame in a manner which accommodates lateral thermal expansion, and the lateral ends are tied vertically to the supporting frame to prevent thermal bowing characteristic of prior art systems.

Abstract: A hot plate for a double racer used in the manufacture of corrugated paperboard includes a substantially all copper construction which enhances thermal conductivity and heat transfer efficiency. Steam for heating the plates is provided through an array of copper tubes extending between manifolds on opposite sides of the hot plate, all in a manner which obviates the need for heavy pressure vessel construction. The hot plate is allowed to float on its supporting frame in a manner which accommodates lateral thermal expansion, and the lateral ends are tied vertically to the supporting frame to prevent thermal bowing characteristic of prior art systems. The heating system is also applicable to a rotary preheating drum where the same benefits of thermal conductivity and heat transfer efficiency are attained.

Abstract: A multiphase induction motor having concentrated phase windings utilizes adaptive torque control based on detection of asymmetry in the magnetic field density and corrective adjustment to restore symmetry based on voltage differences in the torque phase motor windings.

Abstract: An apparatus and method for slitting a stack of folded corrugated paperboard boxes utilizes a thin slitting blade mounted for continuous movement through a slitting station and defining a vertical slitting plane. A stack supporting table straddles the slitting blade to support a stack of boxes in a stand-by position above the blade. Adjustable upstream and downstream squaring devices are operative to square and center the stack in the cutting plane and a vertically reciprocable ram operates to move the stack and the supporting table downwardly past the blade against a table biasing force to slit the stack into two half-size stacks. The squaring device is operable to re-square the slit half-size stacks prior to conveyance out of the slitting station. The slitting run of the continuous blade operates in a rigid blade holder which is adjustable to compensate for blade wear and to maintain the cutting edge of the blade in a fixed plane.