GB2245253A - Composite packaging blanks and methods of their manufacture - Google Patents

Abstract

A composite box blank erectable into a packaging box comprises a cardboard section 10 which is cut and creased and has a window 40 which extends round a corner of the erected box, and a plastics, transparent or translucent section which covers the window 40. Said section is devoid of any creasing in the initial state of the blank but when the blank is erected into the packaging box, creases along the line which defines said corner. The blanks are manufactured by adhering cut sections of the plastics material to cut and creased blank portions. <IMAGE>

Description

Improvements Relating to Composite Packaging Blanks and Methods of their Manufacture This invention relates to composite packaging blanks and to methods of their manufacture. The invention also extends to packaging containers (boxes) erected from the blanks.

The blanks to which the present invention relate are cut and creased so as to be foldable into packaging containers, referred to herein as boxes, for receiving articles, such as Easter eggs to be packaged therein.

The blanks are described as composite insofar as they comprise a first section of opaque sheet material, typically cardboard, and a second section of transparent or translucent material, typically of plastics. The plastics material is used to cover a window in the first section so that in the erected box the contents are viewable through the second section.

Composite blanks and boxes erected therefrom are of course known and various forms are disclosed for example in British Patents 1327819, 2090230 and 2183218.

In the arrangement disclosed in British Patent 1327819, the first and second sections are connected edge to edge so that the respective sections partly define the outer periphery of the composite blank, whereas in Patent Specifications 2090230 and 2183218 the first section, conveniently referred to hereinafter as the cardboard section, is provided with a window therein and the second section, conveniently referred to hereinafter as the plastics section, covers the window, overlapping regions of the cardboard section and plastics section being secured together typically by means of adhesive.

In each of Patent Specifications 2090230 and 2183218 it is important that the window should extend across at least one line which will form a corner in the finished box. On that line in the case of Patent Specification 2090230 the plastics material is provided with notches in the edges thereof and a scoring or crease line is provided in the plastic extending between the notches so that the plastics material will fold along the crease or score line when the blank is erected to the box configuration.

In Patent Specification 2183218, a similar construction is envisaged except that the notches are in the cardboard section but again it is important that the plastics material should be pre-scored or cut and that the score or cut line should be in alignment with the notches in the cardboard section to enhance accurate folding of the blank to box configuration.

The present invention is concerned with composite blanks of the nature disclosed in Patent Specifications 2090230 and 2183218 in that a cardboard section is provided with a window which is covered by a plastics section, and the window extends across a line which will define a corner of the box in the erected arrangement of the blank, but it has been discovered that, in accordance with the instant invention, the plastics material can be connected to the cardboard section without any pre-scoring or cutting but that any necessary fold line in the plastics material can be imparted thereto when the composite blank is erected by relative folding of adjacent panels of the composite blank. This appreciation and realisation provides significant advantages because the need to pre-score or crease the plastics material is eliminated.Enhanced production results insofar as production can be performed more quickly, and can be simplified.

Specifically, and in accordance with another aspect of the invention, the method of producing composite blanks comprises cutting the plastics sections from a reel or web of the plastics material, without any pre-creasing or scoring and applying the uncreased plastics sections to the cardboard sections. The plastics sections and cardboard sections may be conveyed one by one and brought together to form composite blanks, the cardboard and plastics sections being fed by appropriate conveying means.

The cardboard sections will of course be cut and pre-creased to enable folding of the composite blank to the erected condition.

Plastics material will be chosen to be of such characteristic and thickness so that it will fold and crease when the composite blank is folded to erected condition.

The aperture in the cardboard section and the plastics section may overlap or bridge one line only which is to form a corner in the erected box, but it is also possible that the aperture and plastics section may bridge two or more of such lines.

In relation to each of such lines, it is preferable that along said line where the plastics material meets the cardboard, there is a small gap between the cardboard edge defining the aperture and the plastics section edge to facilitate the folding of the composite blank. This may be achieved by providing a notch in the plastics material as in Patent 2090230 and/or by providing notch in the cardboard as described in Specification 2183218.

An embodiment of the present invention, and a method of providing composite blanks according to the invention, -will now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a perspective view of a composite blank according to the embodiment of the invention; Fig. 2 is an enlarged plan view of a portion of the composite blank shown in Fig. 1; Fig. 3 is a perspective view of a portion of the composite blank shown in Fig. 2, after folding of the blank; Fig. 4 is a perspective view of the box erected from the blank shown in Fig. 1; and Fig. 5 is a diagrammatic side view of an apparatus for manufacturing composite blanks as illnstrated in Fig. 1.

Referring to Figs. 1 to 4 of the drawings, a composite blank shown in Fig. 1 comprises a cardboard section 10 which comprises four panels 12, 14, 16 and 18 interconnected by hinge lines 20, 22, 24. The panels 12 - 18 are of equal length, and panels 12 and 16 are of equal width and panels 14 and 18 are of equal width but narrower than panels 12 and 16 so that when the blank is erected to box configuration by folding about lines 20, 22 and 24, a rectilinear rectangular cross-section container results.

At its free edge panel 12 is provided with a glue tab 26 connected to panel 12 by means of fold line 28. End panels 30, 32 and 34 are hinged to panels 14, 16 and 18 and are folded over relative to such panels about fold lines 36 in order to complete the erected carton.

The cardboard panel described thus far is conventional in nature and its construction and erection will be well known to those skilled in the art.

The cardboard section is provided with a window aperture 40 which extends across the hinge line 24 (which line eventually will define a corner in the erected box) and where the aperture edge meets line 24, there are notches 42 in the aperture, the purpose of which will be explained hereinafter.

The aperture 40 has an edge defined in panel 18 which is indicated by reference numeral 44 and curves from the extremities of notches 42 in a convex curve as shown in Fig.

1.

The plastics section 46 is applied over the window 40 as shown in Fig. 1, and is glued to panels 16 and 18 where it overlaps same. The plastics section is shown as being rectilinear in nature and is dimensioned as shown in Fig. 2 such that the longer edges 48 are spaced inwardly from the extremities of the notches 42 by the small clearance distance X, but in accordance with the present invention the plastics section 46 is devoid of any pre-creasing or scoring. The plastics section 46 is applied to the cardboard section in a manner described in relation to Fig. 5.

The plastics material is selected so as to have a suitable folding characteristic and the aperture 40 is dimensioned so that a sufficient length of the crease line 24 will remain so that the blank as illustrated in Fig. 1 folds reliably when it is folded by conventional carton folding equipment.

To perform this folding, the composite blank is moved in the direction 50 shown in Fig. 1, through conventional folding and gluing machinery. Glue is applied to the underside of the glue tab 26, and as the blank moves in the first stage of erection panel 12 is folded about panel 20 so that it overlies panel 14 and panel 16. In the next stage of erection, panel 18 is folded about fold line 24 so that it folds over panel 16 and its edge region 52 overlies and becomes adhered to the glue tab 26. During this folding of the panel 18 by conventional folding equipment, a crease is imparted to the plastics material section 46 as indicated by reference 54 in Fig. 3.Arranging for the plastics material edge 48 to be clear of the end of each notch 42 by the clearance X as shown in Fig. 2 enables smooth and efficient folding of the composite blank and also prevents the build up of tearing stress on the cardboard section in the region of the extremity of the notch. Crease 54 forms the continuation of fold line 24 in the erected container as shown in Fig. 4.

When the blank is folded by folding and gluing machinery from the Fig. 1 position, it is of course folded to what is known as flattened skillet form, and in that form is shipped to the customer who will eventually perform the final erection and insertion of the products to be held in the erected containers.

Referring now to Fig. 5, the composite blanks 100 each as shown in Fig. 5 are manufactured in accordance with the method shown. The cardboard sections 10 are fed on a feed table 102 to a separating roller 104 by which the individual cardboard section blanks are moved on a conveying table 106 in the direction of arrow 108. Roller 104 indicates in the direction indicated by arrow 110.

The travelling cardboard sections 10 first meet an adhesive application roller 112 which is a gravure roller which applies a stencil of adhesive to each of the blanks 10 around the window aperture therein for the adherance thereto of the plastics sheet sections 46 which are applied downstream of the roller 112. A metering roller 114 cooperates with roller 112, and with an appropriate tray 116 forms a reservoir for the adhesive 118. Rollers 114 and 112 rotate as indicated by the arrows thereon, so that the adhesive is applied by the stencil portion 120 of the roller 112 to the individual cardboard sections 10 in accordance with the stencilled pattern.The thus stencilled cardboard sections 10 next move to the applicator station for the plastic sections 46 as shown in Fig. 5, and these sections 46 are applied by a pressure roller 122 which carries the plastic sections 46 on the periphery thereof and applies same to the adhesive on the cardboard sections 10 to produce the composite blanks 100.

The plastics material sections 14 are provided by a roll 124 of the plastics material. The material is uncreased in that it is devoid of any precreasing or scoring to such an extent that the plastic sections 46 have no precreasing or prescoring lines therein. The plastics material in being unwound from the roll 124 passes round guide rollers 126, 128 and 130 as shown and then to a cutting roller 132 which cuts the plastic sections 46 to length. As explained herein the sections 46 in this embodiment are rectangular panels, but if in accordance with other embodiments they are provided with side notches, then the cutter roller 132 will be provided with appropriate V-cutters to form said notches during the severing of the sections 46 from the roll of material 124.

The roll 124 unwinds as indicated by the arrow and cutter drum 132 and pressure roller 122 rotate in the directions of the arrows indicated thereon.

The process is continuous and the cardboard sections 10 are fed one by one and in sequence. The plastics material sections are applied to the cardboard sections in synchronism therewith and in the correct registry with the windows in the cardboard sections as illustrated in Fig. 1.

The plastics material of the second section may be any suitable. Thus, it may comprise an acetate sheet material, PVC polyethylene or the like. It will be of appropriate thickness as will be the cardboard material, as it has to crease neatly when the blank is erected to box shape.

Claims (8)

1. A composite blank erectable by folding into a packaging box, comprising a first section of an opaque cut and creased sheet material, said first section having a window which is located so as to extend across a line which defines at least one corner in the erected box, and a second section of a transparent or translucent sheet material which is applied to the first section so as to cover the window, but is devoid any pre-creasing or scoring along said line, the material of the second section being such that it will crease along said line defining said at least one corner in the erected box.

2. A composite blank according to Claim 1, wherein the first section has aligned creases along said line and to opposite sides of the window, said second section having a width along said line slightly less in length than the distance between the said aligned creases.

3. A composite blank according to Claim 2, wherein the edges of the second section are notched towards the said line.

4. A composite blank according to Claim 2 or 3, wherein the edges of the window in said first section are notched towards the said aligned creases.

5. A method of producing composite blanks which are erectable into packaging boxes, and which comprises a first section of an opaque cut and creased sheet material having a window which is located so as to extend across a line which defines at least one corner in the erected box, and a second section of a transparent or translucent material, said method comprising the steps of: a) conveying said first sections in sequence along a feed path; b) cutting said second sections from a roll of the material of the second sections as the roll is unrolled; c) adhering said cut second sections in synchronism to said first sections so that the second sections cover the windows of the first section; the roll material forming the second sections being devoid of creases and the method being devoid of any step imparting any creasing to the second sections.

6. A method according to Claim 5, including the step of applying a stencil of adhesive to said first sections around said window as the first sections move in said feed path, and applying the second sections to said adhesive for adhering the second sections to said first sections.

7. A method according to Claim 6, wherein the second sections are applied to the first sections by means of a pressure roller.

8. A method according to Claim 6, wherein the adhesive is applied by means of a gravure roller.