IE81012B1 - A method for producing blanks of corrugated paperboard - Google Patents

Abstract

A web 10 is drawn across a heated bed 11 and, during heating, is passed under a roller section 20 comprising a number of rows 21 of independently movable individual rollers 22 to promote even heating and hence adhesion within the web 10. The webs 10 are formed into blanks which are delivered along output lines 35, 36 to a trolley which delivers the blanks to a palletisation station 39. A pallet 51 mounted on a wheeled bogey 52 runs underneath a conveyor 37 to receive the blanks and, when loaded the pallet is delivered to an output line for packaging the palletised blanks.

Description

A Method for Producing Blanks of Corrugated Paperboard The invention relates to a method of producing blanks of corrugated paperboard which are used for manufacturing packaging, including boxes.

One of the difficulties in manufacturing corrugated paperboard blanks is in achieving an efficient adhesive bond between the corrugated sheet or sheets and the liner or liners. Conventionally, a heated bed is used, however, differential heating of the bed results in warping of the upper surface of the bed and consequent warping of the corrugated paperboard with adverse effects on the adhesive bonding and in the further handling and appearance of the corrugated paperboard product.

According to the invention there is provided a method for producing blanks of corrugated paperboard comprising the steps of: forming flutes across a paper web; applying adhesive to the tips of the flutes on one side of the flutes; applying a first liner to the adhesive on one side of the flutes to form a single face board; applying an adhesive to the flute tips on the other side of the web; applying a second liner to the adhesive on the flute tips on the other side of the web; drawing the web thus formed across a heated bed; -2passing the web, during heating, under at least three roller sections, which sections are spaced apart in the longitudinal direction of the drawn web; the roller sections forming leading and trailing roller sections with respect to each other; the roller sections comprising one or more rollers, the sections which comprise more than one roller have laterally adjacent independently moveable individual rollers which are substantially co-axial in each roller section to promote even heating of the adhesive across the web; wherein each trailing roller section extends progressively further transversely across the web than its leading roller section such that the final trailing roller section extends fully across the web; biasing the individual rollers downwardly onto the web to conform with the contour of the web across the heated bed to promote even heating of the adhesive to its gelatinisation temperature across the web; and cutting the corrugated web to form blanks of a desired size.

In one particularly preferred embodiment of the invention, the method includes the step of monitoring the length of paper drawn from a mill roll. Preferably, the length of paper is monitored by monitoring the number of revolutions of a guide roller over which the paper is passed.

In a further embodiment of the invention, the method includes the steps of: delivering stacks of corrugated board blanks to a stack conveyor; conveying the stacks of blanks to a palletisation station; placing a stack of blanks on a pallet at the palletisation station; and it *1 5 conveying the pallet with the stack in place away from the palletisation station on a pallet conveyor. In a preferred arrangement, at the palletisation station, a pallet is lowered down a ramp to a position below the level of the stack conveyor, a stack is loaded onto the lowered pallet, and the loaded pallet is raised and delivered to the pallet conveyor. Preferably, the direction of travel of the stack of blanks is turned through 10 substantially 90° at the palletisation station. 15 The invention will be more clearly understood from the following description thereof, given by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a plan view of a pressure roller section; 20 Figure 2 is an end view illustrating the operation of the rollers; Figures 3 and 4 are side, partially cross sectional views of one of the rollers in different positions of use; 25 1 Figure 5 is a plan view of another roller section used in the method of the invention; Figure 6 is a plan view of a palletising station used in the method of the invention; 30 Figures 7 to 9 are side views illustrating the operation of the palletising station; and -4Figures 10 to 12 are perspective views illustrating the operation of the palletising station.

In the method for producing blanks of corrugated paperboard according to the invention, flutes are first formed across a paper web, a liquid adhesive is then applied to the tips of the flutes on one side thereof and a first liner is applied to the adhesive to form a single face board. Adhesive is then applied to the flute tips on the other side of the web and a second liner in the form of a single web of paper or another single face board is applied to the adhesive to form a web 10 which is drawn across a heated bed 11. The web 10, during heating, is passed under a roller section 20 comprising a number of rows 21 of independently moveable individual rollers 22 extending at least partially across the web 10.

In the configuration illustrated in Figure 1, the rollers in each row extend fully across the web. The roller configuration of Figure 1 is not in accordance with the present invention.

Figure 5 illustrates a roller configuration in accordance with the present invention, there are leading roller sections and trailing roller sections, the rollers of the trailing roller sections extending fully across the web while the rollers of the leading roller sections extending only partially across the web. The arrangement of Figure 5 promotes bonding of the adhesive in those areas of the web which are subject to the highest forces preventing high adhesion taking place.

The rollers 22 are supported in individual bearings 25 (see Figs. 3 and 4) and are mounted to biassed downwardly to automatically follow the contour of the web 10 to promote adhesive bonding within the web.

It will be noted that the rollers 22 of the or each roller section 21 are substantially co-axial to promote even heating of the adhesive and consequent strong bonding across the web. -5In operation, the individual rollers are automatically biassed downwardly on to the web 10 to conform with the contour of the web across the heated bed and consequently to promote even heating of the adhesive to a gelatinisation temperature across the web.

After gluing of the adhesive, the corrugated web is cut to a desired size to form blanks for forming cartons and the like.

Referring particularly to Fig. 6, different lengths of blanks are delivered along outlet lines 35, 36 to a trolley line 37 extending parallel to the main line 34. Stacks of corrugated board are delivered along the output lines 35, 36 to the trolley line 37 which delivers the stacks of corrugated board to a palletisation station 39 at which the stacks of corrugated board are transferred to a pallet which is delivered along a line 44, for packing, for example, by strapping.

Referring to Figs. 7 to 12, the operation of the palletisation station 39 is illustrated in more detail. Stacks of corrugated paperboard blanks 50 are palletised on a pallet 51 as follows. A pallet 51 is mounted on a wheeled bogey 52 which runs down a ramp 55 below the conveyor 37 to present the trailing comer of the pallet 51 to the stack 50 of paperboard blanks. The bogey 52 carries an upright guide 53 against which the stack 50 is pushed to position the stack correctly on the pallet 51. The bogey 52 is then drawn back up the ramp 55 and the stack 50 is correctly positioned on the pallet 51 which is delivered along the output conveyor line 40.

In the method of the invention, the length of paper for the various liners and corrugations is monitored. Typically, each paper web is led over a guide roller which is provided with a marking which interfaces with a monitor in the form of an electronic eye or the like to count the number of rotations of the guide roller and hence the length of the web passing over the roller. This information is used -6to control the process and in particular to confirm that the length of paper on a supplied mill roll is in accordance with specification.

The invention provides a highly effective method of producing corrugated 5 paperboard.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (8)

Claims

1. A method for producing blanks of corrugated paperboard comprising the steps of:forming flutes across a paper web; applying adhesive to the tips of the flutes on one side of the flutes; applying a first liner to the adhesive on one side of the flutes to form a single face board; applying an adhesive to the flute tips on the other side of the web; applying a second liner to the adhesive on the flute tips on the other side of the web; drawing the web thus formed across a heated bed; passing the web during heating under at least three roller sections, which sections are spaced apart in the longitudinal direction of the drawn web; the roller sections forming leading and trailing roller sections with respect to each other; the roller sections comprising one or more rollers, the sections which comprise more than one roller have laterally adjacent independently moveable individual rollers which are substantially co-axial in each roller section to promote even heating of the adhesive across the web; -8wherein each trailing roller section extends progressively further transversely across the web than its leading roller section such that the final trailing roller section extends fully across the web; biasing the individual rollers downwardly onto the web to conform with the contour of the web across the heated bed to promote even heating of the adhesive to its gelatinisation temperature across the web; and cutting the corrugated web to form blanks of a desired size.

2. A method as claimed in claim 1 including the step of monitoring the length of paper drawn from a mill roll.

3. A method as claimed in claim 2 wherein the length of paper is monitored by monitoring the number of revolutions of a guide roller over which the paper is passed.

4. A method as claimed in any preceding claim including the steps of: delivering stacks of corrugated board blanks to a stack conveyor; conveying the stacks of blanks to a palletisation station; placing a stack of blanks on a pallet at the palletisation station; and conveying the pallet with the stack in place away from the palletisation station on a pallet conveyor.

5. A method as claimed in claim 4 wherein, at the palletisation station, a pallet is lowered down a ramp to a position below the level of the stack -9conveyor, a stack is loaded onto the lowered pallet, and the loaded pallet is raised and delivered to the pallet conveyor.

6. A method as claimed in claim 5 wherein the direction of travel of the stack 5 of blanks is turned through substantially 90° at the palletisation station.

7. A method for producing blanks of corrugated paperboard substantially as hereinbefore described with reference to the figures 3, 4 and 5.

8. 10 8. Corrugated paperboard whenever produced by a method as claimed in any preceding claim.