GB2076370A - Packaging dividers - Google Patents

Abstract

A packaging divider of the expandable honeycomb type comprises a set of strips of card material formed of fibrous matter each said strip having, spaced regularly apart in its length direction, a set of transverse zones (9) in which is positioned adhesive (10) securing the strips in face to face relationship, and the transverse zones of at least the first two strips and the last two strips being bounded by embossment lines 8. <IMAGE>

Description

SPECIFICATION Packaging dividers The present invention relates to packaging dividers.

Packaging dividers formed of structural honeycomb material having a generally hexagonal cellular structurn when expanded are used for the packaging of articles with the advantages that each article is accommodated in, and protected by, its own individual cell and that the honeycomb material is produced, and can be transported and stored, in a compact unexpanded state. Automatic apparatus for expanding the dividers and packaging articles, especially apples, therein is described in our British Specification No. 1,584,256 which illustrates the general principles involved.

Structural honeycomb material is produced and used for two main purposes viz. (a) for packaging dividers as aforesaid and (b) for structural use as a core material in laminated structures, eg. doors, or as a grid material eg. for ventilating applications. In both cases, the material consists of strips of sheet material, usually paper or thin cardboard, secured together in face to face relationship by spaced bands of adhesive so positioned that the bands at one face of any constituent strip which lies between two other consistent strips are staggered with respect to those at the other face thereof. The material for structural use is produced with as many strips as possible secured together. It is unusual for a piece of the material to be produced with less than 50 constituent strips.The tendency is to produce the material in continuous form with a very large, indefinite, number of strips secured together. Additionally, the length of the strips and thus the width of the material is made as large as possible, eg. 1 metre or more, in the interests of production speed.

In contrast, the material for purpose (a) must be convenient to handle for packaging purposes. It is provided in the form of slices (individual dividers) which can be taken one by one to provide cells, not necessarily complete cells, one for each article to be accommodated. The length of the strips is limited, seldom being more than 40 cm, and so is the number of constituent strips which is rarely more than 30. Of these strips, the first and last are secured only to the second and last-but-one strips respectively so that their outer faces are free from adhesive.

Honeycomb materials for purposes (a) and (b) are different produces. Their basic geometries are simi lar but the substitution of one for the other is not practicable.

By the present invention, there is provided a packaging divider of the expandable honeycomb type which comprises a set of strips of card material formed of fibrous matter each said strip having, spaced regularly, apart in its length direction, a set of transverse zones, the transverse zones of at least the first two strips and the last two strips each being bounded in the length direction of the strips by a pair of embossment lines and, securing the strips together in face-to-face relationship, bands of adhesive positioned in said transverse zones and arranged such that each of those of the strips which is positioned between two other strips has the securing bands at one face alternating with the securing bands at the other face.There is further provided a method of packaging articles using a divider as aforesaid, which method comprises expanding the divider to an open-cellular state by tension applied to the first and last strips, releasing the tension and introducing the articles into the cells.

The tension is conveniently applied at the adhesivefree transverse zones of the first and last strips.

These zones, of course, alternate with zones by which the first and last strips are adhered to the next strips. In one preferred form of this method, the expanded divider is fitted into a packaging container before the articles are introduced into the cells, the container being so dimensioned that it holds the divider in an expanded state.

When honeycomb material is expanded from the unexpanded state (in which it is normally manufactured, transported and stored) to the open cellular state it contracts across the direction of expansion.

The constituent sheet material has a degree of resilience which causes the material to tend to revert to a iess-expanded state when the force applied in the expansion is released. By restraining it against the accompanying transverse expansion, the material can be held in a expanded state. Advantage is taken of this factor in some applications. For example, in manual packaging, the divider is overexpanded by manual pulling and fitted into a packaging container so dimensioned that the walls of the container hold it in an expanded state by obstructing the transverse expansion.

It is found that with a divider as provided by the present invention an improved cellular configuration is obtained. Previous dividers have tended to present an irregular configuration when located in the container. This has been especially true of the first and last rows of cells which have tended to be grossly distorted, even to the extent of being almost closed. In the final package, the cells are, or may be, held open by the articles. Satisfactory packaging has been achieved but at the expanse of manipulating the cells before or during the insertion of the articles.

A substantial improvement is obtained by providing only the first and last pairs of strips with the embossment lines. Best results are obtained by providing all the strips with embossment lines. This arrangement is also the simplest to adopt in manufacturing the dividers from a single web of the material, eg. as described in our Specification No.

1,216,469. The manufacturing apparatus requires only the addition of a single embossing apparatus to be operated continuously.

The formation of embossment lines giving the required effect is found to be achieved reliably in a very simple manner. The embossment involves localised relative movement or severing of the interlocking constituent matted fibres to give localised stretching, cutting or tearing, of the card material. An adequate effect is obtained without significant weakening by embossing to form embossment lines (involving stretching, cutting or tearing) of an interrupted type leaving, for example, from 35 to 60% of the card unmodified between individual formations.

Card material of the kind normally employed for the manufacture of dividers is formed from re-cycled waste. Its thickness varies both locally and from batch to batch. Shallow embossment, especially scoring, presents some difficulties for this reason.

Best results have been obtaned by deliberate severing through the card at localised positions of the embossment lines. This may be achieved by toothed blades of the rotary type of which the teeth are each bound by a pair of edges which are convergent in the outwards radial direction. Variations of the cutting action of such blades, encountered in practice, are well tolerated.

Reference has been made herein to the adhesive securing the strips in face to face relationship being positioned in the transverse zones. By arranging that the width occupied by the individual bands of adhesive is less than the width of the zones, the positioning of the adhesive relative to the embossment lines is rendered non-critical. This can be an important factor in practice, especially where the dividers are required for fruit packaging. The cell sizes required over a supply of dividers depend upon the distribution of sizes of the fruit to be packaged which in turn depends upon the weather conditions in the growing season. The production machinery for the dividers must be adjusted rapidly at short notice.

In a typical case, the embossment lines are 18mm apart, centre to centre, and the adhesive bands are 6.4mm wide. With a spacing of 130mm (nominal) between the bands of adhesive at one face of any layer, variation of the precise positioning of the adhesive within the zones produces no visually objectionable effect.

The embossment lines of the present invention are of course not intended to perforate the card material although perforation techniques may be chosen for production purposes. The lines do not have the ventilating function of the rows of slits which are sometimes provided in honeycomb for certain applications, eg. to avoid local high vapour pressure in panel production by hot lamination. It has been proposed to provide cell-to-cell ventilation in dividers for fruit packaging. This is not excluded from the scope of the present invention. For such purpose, holes may be punched in those parts of the card which are to provide walls of a single thickness; (there are two walls of double thickness and four of single thickness per cell). Relatively large apertures are required for ventilation in fruit packaging, localised excess pressures being negligible.

The following description in which reference is made to the accompanying drawings is given in order to illustrate the invention. In the drawings: Figure 1 shows in plan part of a divider locating articles within a packaging container.

Figure 2 shows part of a divider over-expanded preparatory to use, Figure 3 shows a typical example of a conventional divider when first introduced into a packaging container, Figure 4 is a plan showing part of a divider according to the present invention, Figure 5 is a cross section of part of the thickness of the divider of Figure 4 taken along line V---V in Figure 4.

Figure 6 shows the behaviour of a divider according to Figures 4 and 5 when first introduced into a packaging container, Figure 7shows, in perspective, a preferred embossing apparatus having toothed wheels for forming the embossment lines, Figure 8 shows part of one of the toothed wheels in side elevation, Figure 9 shows one of the teeth of the toothed wheel on an enlarged scale, and Figure 10 is a cross-section taken at X---X of Figure 9.

Figure 1 shows in idealised form part of a layer of articles (eg. apples), represented by the circles.

Those cell walls of the divider which are of double thickness are indicated at Din Figure 1 and elsewhere. The articles labelled X are accommodated in incomplete edge cells of the divider and, in part, held by a container wall 1. This wail meets another wall 2 to form corner 3 of the container.

In the usual practice, (a) the container is rectangular in cross section and the arrangement in the region of the three other corners is similar to that shown in Figure 1 and (b) the depth of the container is occupied by several layers which are separated by cardboard layer pads - see the said Specification of Application No.50455/76.

With manual packaging, which is frequently employed, the divider is over-expanded by engaging the fingers in some or all of the cells defined between the first and last pairs of constituent strips and puliing in direction P---O. Two fingers 4 and 4' of one hand engaging the cells of the first pair are shown diagrammatically in Figure 2. Fingers on the other hand are used similarly to engage the cells of the last pair (not shown). As the next step, the divider is allowed to contract in direction P---O, with consequent expansion in direction R---S, and is inserted in the container. Engagement of the expanding divider between wall 1 and the wall (not shown) opposite thereto tends to hold the divider in the open cellular state.

A typical result at this stage is shown in Figure 3.

The cells, especially in the neighbourhood of wall 2 and its parallel counterpart are irresular. Cell 5 is virtually closed and edge cells 6 and 7 are poorly dimensioned and shaped. Defects such as these have to be corrected by manipulation with the fingers and/or the articles to be packaged.

With the divider of Figures 4 and 5, the constituent strips of the divider are formed with embossment lines 8, as hereinbefore described, which bound transverse zones 9. In the cross section of Figure 5, the first three constituent strips only (there are 12 in all) are shown. Their thickness is exaggerated as is that of the bands 10 & 11 of adhesive by which the strips are secured together in face to face relationship. As will be seen, the bands 10 at one face of strip 12 are positioned in alternate zones and the bands 11 at the other face of strip 12 are positioned in the zones therebetween. This arrangement continues throughout the divider, and alternate zones of the first and last strips thereof are free from adhesive.

As will be seen the embossments alternate in their orientation from one strip to the next. This effect is obtained because the block of honeycomb from which the divider is cut is formed by lapping a continuous web which has been passed through a rotary embossing device and then adhesive applicators by which adhesive is applied to both faces of the web - see our Specification No. 981,875.

When the slice of Figures 4 & 5 is expanded and inserted in a packaging container as described with reference to Figures 2 and 3, the more regular cell pattern shown in Figure 6 is achieved. The adhesivefree zones 9 of the first and last strips assist in keeping the first and last rows of cells open. A much more regular cell pattern than that of the Figure 3 type is obtained with resulting ease of manipulation.

The web embossing apparatus of Figure 7 has a roller 13, suitably driven, and an idler roller 14 carried by arms 15' and 16 pivotally mounted at 15' and 16'. Roller 14 can be raised from and lowered into the position shown by pneumatic rams 17 and 18.

Roller 14 is formed in sections mounted together with toothed circular blades 19 upon a common shaft 20. These blades are arranged in spaced-apart pairs, each of which defines the boundaries of a transverse zone of the dividers. The web of card material, having a nominal thickness of, for example, 400 microns is embossed by passage through the nip between rollers 13 and 14 and then passes to an applicator for applying longitudinal bands of adhesive within the zones. This application of adhesive is omitted at regular intervals so that honeycomb formed from the web material has a number of layers appropriate for dividers - Specification 1,216,469 refers.

Driven roller 13 is grooved at 21 to receive the web-perforating teeth of blades 19.

Each blade 19 is of overall diameter 85mm and formed with 34 triangular teeth 22 of apex angle 55 .

In the region of its apex 23, each tooth is ground at both faces and both edges to the cross-section shown in Figure 10. The blades are of annular configuration with an inner periphery 24. Each is provided with three holes 25 spaced 1200 apart for engagement with retaining fittings (not shown in roller 14.) This embossing apparatus is simple in construction, requires little maintenance and is reliable in operation with card stock of different grades and inconsistent quality.

By the present invention, the packaging of articles is simplified. This is especially so when the dividers are expanded, and the articles are inserted into the cells, by hand. in a short test, the speed of an experienced packer was increased by from Sto 10%.

Manual packaging is of considerable importance, especially in the fruit trade where it is concentrated into short seasons and the inclusion of defective articles of fruit has to be avoided. The tension exerted in manual over-expansion of the dividers, even by a single packer, varies widely. Tensile weakening by the embossment lines must therefore be limited and is preferably avoided, as in the preferred cases described where breakdown under tension is by yielding oftheadhesive-bound parts, usually by tearing away the surface. The number of complete end cells across the width, ie. across the expansion direction, of the divider is in practical cases small enough for convenient manipulation by the packer. Figure 2 shows only two complete end cells but represents a practical case.

It will be appreciated that the foregoing description of preferred apparatus and preferred embodiments of the invention is given for purposes of illustration only, and that various departures may be made therefrom by those skilled in the art without departure from the scope of the invention claimed.

Claims (9)

1. A packaging divider of the expandable honeycomb type which comprises a set of strips of card material formed of fibrous matter each said strip having, spaced regularly apart in its length direction, a set of transverse zones, the transverse zones of at least the first two strips and the last two strips each being bounded in the length direction of the strips by a pair of embossment lines and, securing the strips together in face-to-face relationship, bands of adhesive positioned in said transverse zones and arranged such that each of those of the strips which is positioned between two other strips has the securing bands at one face alternating with the securing bands at the other face.

2. A divider according to claim 1 in which the adhesive is distributed in bands having a width less than the width of the transverse zones.

3. A divider according to either of claims 1 or 2 in which the embossment lines are embossment lines of the interrupted type produced by localised severing of the card material.

4. A divider according to claim 3 in which the embossment lines leave from 35 to 60% of the card unsevered between the severed parts of said lines.

5. A packaging divider substantially as hereinbefore described and illustrated by reference to the accompanying drawings.

6. A method of packaging articles which comprises expanding a divider according to any one of claims 1 to 5 to an open-cellular state having open cells bounded by the strips including the first two strips and the last two strips by tension applied to the first and last strips, releasing the tension and introducing the articles into the cells.

7. A method according to claim 6 in which the expanded divider is fitted into a packaging container before the articles are introduced into the cells, the container being so dimensioned that it holds the divider in an expanded state.

8. A method of packaging articles by a method according to either of claims 6 or 7, substantially as hereinbefore described and illustrated by reference to the accompanying drawings.

9. A method of producing packaging dividers of the expandable honeycomb type substantially as hereinbefore described and illustrated by reference to Figures 7 & 10 of the accompanying drawings.