The present invention relates to a container and methods of making containers with features providing enhanced load bearing characteristics.

BACKGROUND TO THE INVENTION

Containers made from corrugated paperboard usually come in a rectangular box shape. These containers may contain material or items to be shipped. They can be heavy when containing material or items.

Typically, the containers may be stacked ontop of each other during storage and/or distribution. Accordingly, the containers are designed to be able to take a certain degree of top loading. Such top loading may be static top loading or in the case of the containers being stacked in a vehicle, during transportation, the top loading may be dynamic. High static or dynamic top loading can cause the sidewalls of a container to fail. This failure usually occurs in the form of buckling that results in a curved sidewall crease 11 as shown by way of the dotted line in figure 1 and 2. If it is intended that a container will be subject to greater top loading, the container usually requires greater sidewall thickness in order to improve performance and resist buckling and/or failure. This means that more material is required to be used to achieve this, that correspondingly increases the cost of the container. It is therefore an object of the present invention to provide a container and/or method of forming a container and blank that can, at least under some top load conditions, improve the top load bearing performance, preferably without using thicker sidewall material or to at least provide the public with a useful choice. In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

SUMMARY OF THE INVENTION

According to a first aspect the invention broadly comprises a container comprising : a rectangular base and upstanding side walls projecting from the base to define a containment region,

at least one sidewall having a feature extending across the would be line of creasing of the sidewall where a failure crease would form due to an excessive top load placed on the sidewall, to isolate the vertical sidewall edge adjacent said feature from said failure crease.

According to a further aspect the invention broadly comprises a container comprising : a rectangular base and upstanding side walls projecting from the base to define a containment region,

at least one sidewall having a feature extending across the would be line of creasing of the sidewall where a failure crease would form due to an excessive top load placed on the sidewall, to isolate at least one or both of the distal ends of the vertical sidewall edge adjacent said feature from said failure crease.

According to another aspect the feature is a linear feature.

According to another aspect said feature is elongate and extends in a direction not parallel to said failure crease.

According to another aspect said feature is a line of weakness. According to another aspect the feature is a crease or score-line. According to another aspect the sidewall has at least two features. According to another aspect each feature is discrete from the others. According to another aspect the feature is an extra layer of material on said side wall.

According to another aspect said extra layer is a line of adhesive, or paperboard, or plastic, or a thicker cross sectional thickness.

According to another aspect the feature is a line of perforation of as least part of the sidewall.

According to another aspect the feature is formed on the inside of the sidewall. According to another aspect the feature extends from near the sidewall edge and projects upwardly toward the top edge of said sidewall.

According to another aspect the container is an erectable container.

According to another aspect the container is formed from planar material.

According to another aspect the planar material of said container is a paperboard including a laminate structure.

According to another aspect said laminate structure has a corrugated core.

According to another aspect the said corrugate core is sandwiched between two sandwiching layers of paper or paperboard.

According to another aspect the feature is defined at one side of said sidewall, preferably at one sandwiching layer.

According to another aspect the corrugation flute direction is vertical.

According to another aspect the sidewalls are a corrugated paperboard.

According to another aspect the sidewalls are rectangular. According to another aspect the feature extends in a direction that is perpendicular to a direction that a would be failure crease extends at a point where it would encounter the feature.

According to another aspect the feature extends at between 20 to 70 degrees to the top edge of the sidewall panel.

According to another aspect the container is flap closeable.

According to another aspect the vertical sidewall edge and/or distal end thereof is at least partially isolated as a result of the feature deflecting the crease line away, preferably to the top edge of the sidewall.

According to another aspect the invention broadly comprises in a container comprising : a rectangular base and upstanding side walls projecting from the base to define a containment region,

at least one side wall having a feature located in a position to intercept a side wall failure crease that can form due to an excessive top load placed on the sidewall to isolate the vertical sidewall edge adjacent said feature from the side wall failure crease.

According to another aspect the invention broadly comprises a container comprising : a rectangular base and upstanding sidewalls projecting from the base to define a containment region,

a vertical zone of each sidewall extending from the top edge of each sidewall to the base and located contiguous each vertical sidewall edge, each sidewall including a feature adjacent each vertical zone that prevents the progression of a sidewall failure crease into said vertical zone. According to another aspect the invention broadly comprises a method of reinforcing a container of a kind comprising a rectangular base and upstanding sidewalls, to increase the container's resistance to top load sidewall failure, said method comprising :

isolating a zone that extends laterally away from where two adjacent sidewalls abut each other, from a top load formed sidewall crease by introducing a feature into said sidewall that terminates or deflects the progression of the sidewall crease into said zone and/or to where said sidewalls meet and/or a distal end of the line or zone at where the sidewalls meet.

According to another aspect the feature is a linear feature.

According to another aspect said feature is elongate and extends in a direction not parallel to said failure crease.

According to another aspect said feature is a line of weakness.

According to another aspect the feature is a crease or score-line. According to another aspect the sidewall has at least two features.

According to another aspect each feature is discrete from the others.

According to another aspect the feature is an extra layer of material on said side wall. According to another aspect said extra layer is a line of adhesive, or paperboard, or plastic, or a thicker cross sectional thickness of the sidewall.

According to another aspect the feature is a line of perforation of as least part of the sidewall.

According to another aspect the feature is formed on the inside of the sidewall.

According to another aspect the feature extends from near the sidewall edge and projects upwardly toward the top edge of said sidewall.

According to another aspect the container is an erectable container.

According to another aspect the container is formed from planar material.

According to another aspect the planar material of said container is a paperboard including a laminate structure.

According to another aspect said laminate structure has a corrugated core.

According to another aspect the said corrugate core is sandwiched between two sandwiching layers of paper or paperboard.

According to another aspect the feature is defined at one side of said sidewall, preferably at one sandwiching layer.

According to another aspect the corrugation flute direction is vertical.

According to another aspect the feature extends in a direction that is perpendicular to a direction that a would be failure crease extends at a point where it would encounter the feature.

According to another aspect the feature extends at between 20 to 70 degrees to the top edge of the sidewall panel.

According to another aspect the invention broadly comprises a container as herein described and with reference to any one or more of the drawings. According to another aspect the invention broadly comprises a method as herein described and with reference to any one or more of the drawi ngs.

According to another aspect the invention broadly comprises a blank erectable into a container as herein described and with reference to any one or more of the drawings.

The term "comprising" as used in this specification and claims means "consisting at least in part of". When interpreting each statement in this specification and claims that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" a re to be interpreted in the same manner.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described by way of example only and with reference to the drawings, in which :

Figure 1 is an illustration of the prior art container undergoing buckling of the sidewalls approximately along the broken line illustrated due to top loading .

Figure 2 is an illustration of a stack of prior art containers of figure 1.

Figure 3 shows a view of a container sidewall, including loadbearing improvement features.

Figure 4 is a perspective view of a container showing the loadbearing improvement feature that helps isolate the vertical corners from a top load caused sidewall failure crease.

Figure 5 is a perspective view of an open topped container showing the loadbearing improvement features.

Figure 6 is a side view of a sidewall showing a plura lity of features.

Figure 7 shows the features in a slightly different location, and also shows how the features may deflect the crease away from the top corner of a container.

Figure 8 is a perspective view of part of a contai ner sidewall showing a loadbearing improvement feature.

Figure 9 is a sectional view through section AA of Figure 6, showing a loadbea ring improvement feature in cross-section . Figure 10 is a sectional view of an alternative loadbearing improvement feature in cross- section.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With particular reference to Figure 4 there is shown a container 1, or from corrugated cardboard. The container may be an open topped container, as shown in Figure 5, or alternatively a flap closeable (or otherwise topped) container as shown in Figure 4.

The container comprises of a base 2 upwardly from which project a plurality of sidewalls 3. The sidewalls 3 may be made of a corrugated paperboard construction of which Figures 8 and 9 provide more detail. The entire container may be made from a corrugated paperboard construction, and it is anticipated that the paperboard may comprise a number of laminated layers, and may further comprise layers of different materials as is known in the art. For example, it is common to coat paperboard containers with liquid and/or gas impervious membranes in order to improve

characteristics where necessary.

The plurality of sidewalls 3 extend upwardly from the base 2 and are each joined at sides 4 and 5 to respective adjacent sidewalls. The join may be by virtue of a fold of a blank and or other join such as an adhesive join etc. Each sidewall extends to a top opening of the container 1 whether such opening is flap closeable or other. The top edge 6 of each sidewall may hence be a free edge or may be an edge from which a flap is dependent.

Adjacent each vertical edge 8 and positioned at the junction of two adjacent sidewalls, is a vertical corner zone 9 as shown in hatching in Figure 5. For illustration purposes, the corner zone 9 is only shown on one corner of the container 1 in figure 5. The vertical 8 edge has distal ends 15 and 16. In a container as shown in Figure 4 and 5 there are four of such zones at each of the four vertical corners. This zone is a zone of strength of the container in that it creates an effective pillar to help support vertical load through the container (for example, from multiple Containers 1 stacked on top of each other) . The strength is partly achieved due to the adjacent walls extending at an angle to each other, creating a high second moment of area, that resists bending and/or buckling in that zone. This loadbearing zone 9 can, by way of the feature 10 as will herein further be described, be isolated from the sidewall failure crease 11 that may form in at least one (and perhaps more than one, or all) sidewalls of the container when the container is subject to top loading, and begins to buckle.

The feature 10 may for example be a crease, or score line, or other form of weakness as more clearly shown in Figures 8 and 9. Alternatively, the feature 10 May be an area of relative strength, as illustrated

schematically in figure 10. In this embodiment, the feature 10 may be a strip of additional material such as an adhesive, or extra layer of board (or other material), or may be an area that is locally thicker than the remaining sidewall. The feature 10 is preferably located on or at the sidewall, at a location where such a sidewall failure crease 11 would otherwise naturally pass through, or across as it propagates under loading to the sidewall edge 8. Such natural propagation during buckling failure may be to the edge 8, between the ends 15 and 16 of the edge 8, or to the distal end 15 and/or 16 (i.e. the corners of the container).

However, due to the presence of the feature 10, a sidewall failure crease 11 that is created due to any undesirable and/or excessive top loading, does not cross the feature 10, and/or is deflected away from the sidewall edge 8. Alternatively, the failure crease 11 is deflected away from the distal ends 15 and/or 16 of the edge 8, where such a feature is located in the path of such a failure crease.

During top loading of a standard container 1, failure crease 11 propagation encroaches the area adjacent the vertical corner of a container, and the ultimate top load strength of the container can be significantly compromised . This is because normally, the vertical corners provide a significant portion of the resistance to container failure (such as crushing, or partial crushing, or vertical collapse, or partial collapse, of the container).

Most vertical load transfer occurs via these vertical corners, so a side wall crease that comes into the top of the vertical corner can cause this part of the box to crumple for example. The loadbearing enhancing feature 10, acts to isolate at least one vertical corner region of a container from sidewall failure creasing to reduce the incidence of a significant top load failure of the container. The feature 10 may be in the form of a straight line, and may be for example a short straight line that is preferably located at substantially 90 degrees to the path of a n expected sidewall failure crease 11. The geometry and/or size of the container will to some degree dictate the likely or expected path of buckling failure crease 11.

For a given geometry, a numerical technique or experiment or observation of failure mode can be used to predict the expected path of buckling failure crease 11.

The angle of alignment between crease 11 and feature 10 may not necessarily be at 90 degrees, but is preferably presented to be at an approximately perpendicular, or at a non-parallel angle to the sidewall failure crease 11.

As shown in Figure 6, the position of the feature 10 is preferably close to a corner 8 and preferably also close to at least the top edge 6 of the container. A feature 10A may also additionally be provided near the base 2 of the container at the sidewall 3. In the most preferred forms each of the sidewalls 3 may include a plurality of such features 10 appropriately positioned to help isolate the zone 9 adjacent each of the edge 8 (preferably each corner 15,16) of the container from the progression of a sidewall failure crease 11, to or towards each edge 8. In the most preferred form the feature 10 is formed on the inside face 12 of a sidewall. This is for example shown in Figure 5 and in Figure 9. The inside face 12 is on the inside of the containment region of the container whereas the outside face 13 faces outwardly from the container. The feature 10 may be a scored line or other formation in a sidewall of the container.

In use, the feature 10 may terminate the progression of a sidewall failure crease 11 or it may deflect such a sidewall failure crease away from the edge 8 and/or zone 9 and/or the distal ends 15/16 of the edge 8. This therefore ensures that the sidewall failure crease 11 does not progress into or towards the vertical pillar structure of the container at a location or locations to help ensure that the container still has at least some, and preferably substantially all of its top load carrying strength intact, and/or to prevent the corners of the container from crumpling. It is preferred that the feature 10 is provided on the inside face of the container because usual failure of a sidewall is outwards. A sidewall bowing out results in a compression failure at the inside face of the corrugated assembly and tension failure on the outside face. Therefore placing a feature 10 on the inside face of the sidewall will have a better outcome for the performance of the container, and additionally means that the feature 10 is not visible from the outside of the container.

A feature 10 may come preferably close to the corner 8 of a container and may for example sit in the range of 30-40mm from the corner depending on the container size.

It may extend as a linear (straight or curved) feature of between 20-70 degrees to the horizontal edge of a sidewall panel.

In some embodiments each side wall preferably has 4 such features, one each located in a respective quadrant (Ql-4) of the side wall, as illustrated in Figure 3. Preferably, the location of feature 10 is proximate more the corner of the quadrant near the corners of the container, than near the middle of the side wall.

In alternative embodiments, the features 10 may only be present in quadrants Q2 and Q3.

It has been found that the geometry and nature of feature 10 can have a significant effect of the overall performance of the container's load bearing performance. For example, if the feature (e.g. crease or other area of weakness) is too large/deep, it can weaken the entire container and have an adverse overall impact. Therefore, it is preferred that the feature only provides a small local weakening of the cardboard sidewalls, sufficient to influence the pathway of failure without significantly weakening the wall. When designed properly, the feature sacrifices a small amount of wall strength, but overall increases the containers ability to resist bucking and improves the ultimate load required for crushing failure. In total it has been found that an increase of around 10% in load bearing capability before failure may be achieved.

In the most preferred embodiments, it has been found that a shallow and narrow crease is preferred as the form of feature 10. A shallow and narrow crease provides an excellent balance between providing a line of weakness for failure to follow, without weakening the wall too much. For example, for a typical corrugated cardboard container a crease depth of around 1mm is most effective. The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.