GB2318568A - Packaging case formed from a blank - Google Patents

Abstract

A packaging case is constructed from a blank of stiff but foldable sheet material, comprising a series of four tube panels 1-4 connected together at parallel fold lines. Each of the two tube panels 1, 4 at opposite ends of the series has a join flange 5, 6 at its free edge. One of the join flanges 5 is glued to the inside of the tube and the other of the join flanges 6 is glued to the outside of the tube.

Description

PACKAGING CASE AND A BLANK THEREFOR The present invention relates to a packaging case and a blank therefor.

Packaging cases are commonly made by folding connected tube panels of a blank of stiff but foldable sheet material into a tube, the tube being completed by a flange connected to an edge of one of the tube panels, and then folding and sealing end panels of the case. The area of the tube joint is probably the weakest part of the case and is susceptible to rupture if the case is dropped. Thus, for cases requiring a high performance specification, a reinforced taped joint is often provided, but such a joint is relatively expensive.

From one aspect, the present invention comprises a packaging case constructed from a blank of stiff but foldable sheet material, the blank comprising a series of tube panels connected together at parallel fold lines, each of the two tube panels at opposite ends of the series having a join flange at an edge thereof parallel to the fold lines, wherein the tube panels are folded to form a tube, one of the join flanges is attached to the inside of the tube and the other of the join flanges is attached to the outside of the tube.

In a preferred embodiment, the case is shaped as a right parallelepiped, the blank having four rectangular tube panels. End panels may be provided at the ends of the tube panels for forming the ends of the case. The join flanges may be attached to the tube by means of glue.

From another aspect, the present invention provides a blank for forming a case as defined above.

In order that the present invention may be more readily understood, reference will now be made, by way of example only, to the accompanying drawings, in which: Figure 1 is a plan of a blank according to a particular embodiment of the invention; Figure 2 is a perspective view of a case in the process of construction from the blank of Figure 1; and Figures 3 and 4 are perspective views of the finished case viewed from two different angles.

Figure 1 shows a planar, unitary blank made of stiff yet foldable sheet material and having a series of four rectangular tube panels 1, 2, 3, 4 connected at fold lines.

The blank is, in this example, formed from double-faced corrugated paperboard, the flutes of which run in the direction of the arrows.

The first tube panel 1 has a trapeziform inside flange 5 running along an entire longitudinal edge of the panel.

The fourth tube panel 4 has a similar trapeziform outside flange 6.

Rectangular end panels 7 are provided at the ends of each of the tube panels 1, 2, 3, 4 and are connected to the tube panels by fold lines.

In order to form a case from the blank shown in Figure 1, the tube panels 1, 2, 3, 4 are folded at their mutually connecting fold lines into a generally tubular form and the flanges 5, 6 are also folded as shown in Figure 2. The inside join flange 5 is glued to the inside of the fourth tube panel 4, the outside join flange 6 is glued to the outside of the first tube panel 1 and the end panels 7 at one end of the case are glued together.

Figure 3 shows the case constructed as described above, with the outside join flange 6 glued to the outside of the tube. Figure 4 is another view of the case showing the inside join flange 5. A case so formed can be filled with any suitable goods, e.g. a bag of pulvurent material. The remaining end flaps 7 can then be sealed.

It will be appreciated that the inner and outer flanges reinforce the case along one of its longitudinally extending edges and thus the invention provides a case of enhanced strength at a relatively low manufacturing cost. The case described above has indeed been found to offer strength properties equivalent to prior art cases having a taped joint.

The expression "tube" as used in this description is to be construed broadly, and a case in which the distance between the "ends" of the tube as described above is not the greatest dimension also falls within the scope of the invention.

Claims (7)

1. A packaging case constructed from a blank of stiff but foldable sheet material, the blank comprising a series of tube panels connected together at parallel fold lines, each of the two tube panels at opposite ends of the series having a join flange at an edge thereof parallel to the fold lines, wherein the tube panels are folded to form a tube, one of the join flanges is attached to the inside of the tube and the other of the join flanges is attached to the outside of the tube.

2. A case as claimed in claim 1, which is shaped as a right parallelepiped, the blank having four rectangular tube panels.

3. A case as claimed in claim 1 or 2, wherein end panels provided at the ends of the tube panels form the ends of the case.

4. A case as claimed in claim 1, 2 or 3, wherein the join flanges are attached to the tube by means of glue.

5. A packaging case substantially as described herein with reference to Figures 3 and 4 of the accompanying drawings.

6. A blank of stiff but foldable sheet material for forming a packaging case, the blank comprising a series of tube panels connected together at parallel fold lines, each of the two tube panels at opposite ends of the series having a join flange at an edge thereof parallel to the fold lines, one of the join flanges being capable of attachment to the inside of a tube to be formed by folding the tube panels, and the other of the join flanges being capable of attachment to the outside of the tube.

7. A blank of stiff but foldable sheet material, substantially as described herein with reference to Figure 1 of the accompanying drawings.