STACKABLE CONTAINER OF PAPERBOARD

Abstract: A container formed from a blank to define indexing longer walls having an inward incline but a double thickness provided by a foldline at the tops thereof so that the indexing projections are receivable within corresponding openings in the base of a corresponding container. Each part of the indexing walls has an extension such that at each end thereof one extension attaches to the outside of an end wall while the other attaches to the inside of an end wall with preferably that attaching to the inside of an end wall through a pair of parallel vertical folds providing a support at least in part for the weight of a stacked container.

Description: STACKABLE CONTAINER OF PAPERBOARD TECHNICAL FIELD The present invention relates to improvements in and/or relating to (containers) cartons, blanks therefor, related packs and methods of use. The present invention relations to a pack formed from a paperboard (preferably a paperboard which is a laminate involving a fluted paperboard medium) which provides a stackable container where a top of one is indexable reproducibly into the base of another. BACKGROUND ART The present invention is an evolution of an indexing pack of a kind as disclosed in our New Zealand Patent Specification No. 237169 (US 5361976) and Registered Design Nos. 25100, 25101, 25605 and 25604. The full content thereof is hereby here included. DISCLOSURE OF INVENTION The present invention however is directed to preferably at least a substantially lidless form capable of providing a stable stack of like containers with their loads where the weight is capable of being taken through the wall structures of such containers without any substantial passage of stress into the load of the containers themselves. A pack form in accordance with the present invention is useful for fruits such as apples etc. It is therefore an object of the present invention to provide such containers, blanks, packs etc. or to at least to provide the public with a useful choice. In a first aspect the present invention consists in a container formed from a blank, said container having a rectangular base, a flap sequence of two flaps (hereafter the "indexing wall flaps") from each of the longer sides of said base, a first flap being connected to the base by a fold line, and the second flap being connected to the first flap by a fold line (preferably through bridge like regions), and wherein each indexing wall flap of each flap sequence has an extension beyond a fold-line or fold-lines (preferably one only) substantially normal to that of a said indexing wall first flap with the base and, in turn, that between two flaps (first and second) of the indexing wall flaps, and a flap from each of the shorter sides of said base (hereinafter the "non indexing wall flaps"), and wherein said base includes inwardly of the fold line thereof with its proximate indexing wall first flap a plurality of openings each to receive a projection formed by a folding (preferably of each bridge like region) of a like container at the fold line between the two indexing wall flaps of a like container, and wherein said container is erected to a walled form with the indexing walls presenting a plurality of upwardly directed projections (preferably formed from said bridge like regions) of the blank and being indexable in through the openings of the base of a like erected container, said indexing walls being inclined inwardly slightly with the extensions of said indexing wall flaps adhesively attached one extension on either side of the closer up folded non indexing wall flap. In some less preferred forms "rectangular" may approach or be "square". Any mechanical equivalent to a bridge form projection can if desired by employed (eg; pop-ups from a fold line) but these will offer less certainty in indexing. Such a form has reduced adhesion, usefulness and overall strength. Preferably said non indexing wall flaps are strictly vertical from the base. Preferably said blank is of a laminate which includes a flute providing medium and the flute direction is such that the flutes extend substantially vertically in said indexing walls. Preferably the extensions of each of the second flap of a non indexing wall flap sequence folds inwardly and is attached inwardly of a non indexing wall flap, and provides with part of the flap thereof (preferably between substantially parallel fold lines) a gusset feature at the corner. Preferably a handle opening is provided through each of the two flaps of a flap sequence of each indexing wall. Preferably each non indexing wall is provided with a recess from the upper extremity thereof to facilitate air flow through. Preferably the angling in of the indexing walls is such as to provide a top to top distance between the indexing walls that is of the order of about 8mm less than that between the fold lines of first flap of the flap sequences from said base. For example preferably an angle of the order of 2° is provided where the spacing between the fold lines from the base of said indexing wall flap sequences is of the order of 396mm. In a further aspect the present invention consists in a blank suitable for construction and/or erection to provide a container as previously set forth. In still a further aspect the present invention consists in as a stack a plurality of containers as previously set forth. In yet a further aspect the present invention consists in adjacent stacks as previously set forth where the inwardly inclined indexing walls are adjacent one to another thereby providing a wedge shape gap which facilitates for cooling, and/or for other purposes, the movement of air. In yet a further aspect the present invention consists in the use of a container in accordance with the present invention. BRIEF DESCRIPTION OF DRAWINGS Preferred forms of the present invention will now be described with reference to the accompanying drawings in which; Figure 1 is a view of a preferred blank in accordance with the present invention- Figure 2 is an erected container in accordance with the present invention when viewed from below showing in the preferred form of the present invention, adjacent each indexing wall, a plurality of indexing openings in the base, Figure 3 is a view from above of two erected containers in accordance with the present invention showing how the indexing wall of the left container, when butted against the preferable non inclined non indexing wall of the other, there is still provided a gap suitable for assisting air movement between the containers of a stack, and Figure 4 shows the stack indexing characteristics of a pair of containers in accordance with the present invention which when a stack is brought into a condition adjacent a like stack (whether in the arrangement as shown in Figure 3) or where indexing wall is again indexing wall (which doubles the size of the gap shown in Figure 3) air circulation is possible about the stacks as well as through each container of the stacks owing to the various openings formed therein. In the preferred form the carton is preferably made from a paperboard, preferably a flute cored sheet faced laminate with the flute direction being in the direction "AA" depicted on Figure 1. Figure 1 shows the blank form of the present invention with the base 1 being provided with a plurahty of openings 2 to the foldline 3 with the first flap 4 of each of the two indexing wall flap sequences of two flaps. The second flap 5 of each of the two flap sequences is connected by a foldline "BB" with the first flap 4 of the indexing wall flap index. Preferably the foldline is at a plurality of bridging regions 6 each of which is to provide upon folding of the second flap 5 inwardly of the container an upstanding projection 14 best seen in the Figures 3 and 4 each of which is adapted to be inserted into a complimentary opening of a like container to those labelled 2. Each of the flaps 4 includes an extension flap 7 while each of the flaps 5 includes an extension 8. The extensions 7 are connected by a foldline 9 to the first flaps 4 while the extensions 8 are connected, preferably, by two foldlines 10 so as to provide a gusset form feature 11 best seen in Figure 4. Where however the paired foldlines 10 are not provided a single foldline can instead be provided substantially aligned with the foldline 9. The foldlines of such extensions are angled as required relative to the base axes. A feature of the present invention is the inward incline of the indexing walls 12 when the carton is erected. The erecting arrangement is such mat the flaps 13, which provide the non indexing walls when upturned, are each sandwiched by a flap 7 and 8 at each extremity thereof with those extensions 7 of the first flap 4 being affixed on the outside face of each non indexing wall flap 13 while those extensions 8 are to be affixed on the insides. In the arrangement as depicted the structure is such that in the flute ninning direction the width of a preferred container is 396mm from foldline 3 to foldline 3. The preferred angle for such a product where the indexing wall structures are to be of the order of 165mm high (external wall measurement) is that the tops of the indexing lugs 14 are approximately 8mm closer together than they would be if the indexing walls were vertical from the base. This angling in of approximately 2° from the vertical on each side allows a more easy index of each indexing lug 14 through its complementary opening 2 and into the accommodating recess region 15 of each of the second flaps 5. Preferably that offset of about 8mm is used for other base sizes ie; the angle adjusts accordingly. In an erected carton with the flaps 7 and 8 adhesively affixed to the non indexing wall flaps 13 a structure as depicted in Figures 2 to 4 results having an advantage of strength owing to the construction, the stacking strength coming from the indexing of wall to wall using the male protuberances much in the same way as disclosed in the aforementioned New Zealand Patent Specification. In addition where a support structure 11 is provided in a corner there is additional strengthening owing to greater resistance to racking forces as well as more vertical structural support. Nevertheless even in the forms without the corner feature 11 a container of acceptable strength is provided which provides an advantage as far as the removal of field temperature from any crop to be stacked in the containers is concerned. This is because the various relief features and openings (including the handle feature 15) all as shown allows a throughput of air through a container above its fruit or other load and under the base of a stacked on top container while additional airflows are possible around the stack owing to the fact that the indexing walls are inclined slightly. A preferred material from which such a container can be made is a dual arch (2 x 160 gm/m 2 ) semi chemical pulp paper corrugated board with outside lines of 290 gm m 2 kraft. Persons skilled in the art will appreciate the alternatives that a structure in the accordance with the present invention provides.

Claims: CLAIMS: 1. A container formed from a blank, said container having a rectangular base, a flap sequence of two flaps (hereafter the "indexing wall flaps") from each of the longer sides of said base, a first flap being connected to the base by a fold line, and the second flap being connected to the first flap by a fold line (preferably through bridge like regions), and wherein each indexing wall flap of each flap sequence has an extension beyond a fold-line or fold-lines substantially normal to that of a said indexing wall first flap with the base and, in turn, that between two flaps (first and second) of the indexing wall flaps, and a flap from each of the shorter sides of said base (hereinafter the "non indexing wall flaps"), and wherein said base includes inwardly of the fold line thereof with its proximate indexing wall first flap a plurality of openings each to receive a projection formed by a folding (preferably of each bridge like region) of a like container at the fold line between the two indexing wall flaps of a like container, and wherein said container is erected to a walled form with the indexing walls presenting a plurality of upwardly directed projections (preferably formed from said bridge like regions) of the blank and being indexable in through the openings of the base of a like erected container, said indexing walls being inclined inwardly slightly with the extensions of said indexing wall flaps adhesively attached one extension on either side of the closer up folded non indexing wall flap. 2. A container of claim 1 wherein there is only one said fold-line to each said extension. 3. A container of claim 1 or 2 wherein said non indexing wall flaps are strictly vertical from the base. 4. A container of claim 1, 2 or 3 wherein said blank is of a laminate which includes a flute providing medium and the flute direction is such that the flutes extend substantially vertically in said indexing walls. 5. A container of any one of the preceding claims wherein the extensions of each of the second flap of a non indexing wall flap sequence folds inwardly and is attached inwardly of a non indexing wall flap, and provides with part of the flap thereof a gusset feature at the corner. 6. A container of claim 5 wherein each said gusset feature is between substantially parallel fold lines. 7. A container of any one of the preceding claims wherein a handle opening is provided through each of the two flaps of a flap sequence of each indexing wall. 8. A container of any one of the preceding claims wherein each non indexing wall is provided with a recess from the upper extremity thereof to facilitate air flow through. 9. A container of any one of the preceding claims wherein the angling in of the indexing walls is such as to provide a top to top distance between the indexing walls that is of the order of about 8mm less than that between the fold lines of first flap of the flap sequences from said base. 10. A container of claim 9 wherein an angle of the order of 2 ° is provided where the spacing between the fold lines from the base of said indexing wall flap sequences is of the order of 396mm. 11. A container substantially as hereinbefore described with reference to any one or more of the accompanying drawings. 12. A blank suitable for construction and/or erection to provide a container as claimed in any one of the preceding claims. 13. As a stack a plurality of containers as claimed in any one of claims 1 to 11. 14. Adjacent stacks each of a kind as claimed in claim 13 where the inwardly inclined indexing walls are adjacent one to another thereby providing a wedge shape gap which facilitates for cooling, and/or for other purposes, the movement of air. 15. The use of a container as claimed in any one of claims 1 to 11.

Inventors: BLOMFIELD GREGORY THOMAS, BURGESS TREVOR GRANT, COE ROBERT WILLIAM, BLOMFIELD, GREGORY, THOMAS, BURGESS, TREVOR, GRANT, COE, ROBERT, WILLIAM
Applicants: BLOMFIELD GREGORY THOMAS, BURGESS TREVOR GRANT, CARTER HOLT HARVEY LTD, COE ROBERT WILLIAM, BLOMFIELD, GREGORY, THOMAS, BURGESS, TREVOR, GRANT, CARTER HOLT HARVEY LIMITED, COE, ROBERT, WILLIAM
Application year: 1996
Main classification: B65D5
IPC codes: B65D5