COLLAPSIBLE CARTON WITH INTEGRAL HANDLE FASTENER

This invention relates to cartons, and is particularly, but not exclusively, concerned with folding or collapsible cartons

For such cartons it is generally desirable to combine structural rigidity and robustness with an ability to collapse into a compact folded configuration

The term 'carton' is used herein to embrace any configuration of hollow structure, closed or open, particularly thin-walled, prefabricated structures

The carton art is well developed, and typically cartons are derived from flat sheet material, subdivided by multiple cuts and creases, cooperatively disposed in an intersecting grid or lattice array, to allow progressive folding and inter-nesting into a three-dimensional erected assembly form

Complex erected configurations with mter-folded and overlying panels require some form of fastening mechanism to maintain the relative disposition of said panels

Many of the known fastenings, such as staples, glue, tape or discrete fasteners impede collapse and re-erection

According to one aspect of the invention, a carton is fabricated from single sheet matenal or carton blank subdivided into an array of panels by a plurality of intersecting cuts and folds, disposed in a cooperative lattice or grid; allowing the panels to be selectively brought into an erected or assembled carton configuration, with a base and upstanding peripheral walls, and wherein the end walls are formed from one or more end wall panels and overlapping flaps extending from the side wall panels,

an outer layer having a handle flap which passes through aligned slots in the layers, to maintain the relative panel positions

Such a fastening, integrated into the carton structure preserves the erected carton configuration without the complication, expense or inconvenience of providing a separate fastening mechanism

An integrated (self-)fastenιng may be combined with a hand-hold or handle

Generally, in a conventional carton, only one (erected) carton configuration is provided for and this is bulky and inconvenient for storage and transit when empty

On the other hand, the alternative, unfolded configuration is generally an extensive/expansive carton blank form - whose bulk is impractical for carriage and storage

Some optional aspects of the present invention provide an alternative compact folded configuration - for convenience of carriage and storage.

According to another aspect of the invention a collapsible carton has alternative folded configurations, one erected into a hollow container or chest, in which a base panel is surmounted by peripheral upstanding side walls formed from overlapping edge panels around the base, interlocked by 'intrusive' side tab handles, and one collapsed into a substantially flat and compact configuration, with overlying elements

In a particular construction, a rectangular panel representing the base of the assembled carton is disposed at the centre of the flat array of rectangular panels

Along the four sides of the base panel are attached two end wall panels and two side wall panels.

The side wall panels have a supplementary panel extending from each side

In the assembled configuration, these supplementary panels are folded at right angles to the

side wall panels, so that they lie flat against the end wall panel

In the assembled configuration, the end walls are some three layers in overall depth

In order to maintain the assembled configuration, the end wall panel and the two additional panels must be held together - by, say, their folded interaction and/or an integrated, say handle/tab, fastening

According to a further aspect of the invention, the overlying layers have aligned apertures the outermost layer having a larger aperture than the other layers and a handle flap, with tab(s) protruding from one or more edges, said tab(s) being deflected as the handle flap is passed through the apertures, and reverting to the protruding position when inside the carton, abutting the inner face of the multiple layer wall and fixed spanning the layers of the end wall.

Desirably, the apertures are of a suitable profile to serve as hand-holds or handles for carrying the carton, a spanning flap forming a handle cushion against the aperture edges cutting the hand

This arrangement not only holds the layers of the end walls together, thus maintaining the assembled configuration of the carton, but also provides reinforced handle apertures with smooth edges for more comfortable handling

The spanning handle flap may have a (proprietary) fastening mechanism, such as a press-stud or complementary pieces of Velcro (Registered Trade Mark), for attachment to the inner face of the inner layer of the erected wall to fix it spanning the layers

Alternatively, in a preferred embodiment, the 'spanning' handle flap has tabs protruding at either side. The protrusions make the handle flap wider than the apertures through which it passes. Upon pushing the handle flap through the aligned apertures, the tabs are deflected

Once the handle flap has been pushed through the apertures, the tabs revert to their protruding positions, abutting the inside layer and preventing the handle flap from automatically returning through the apertures.

Further strength and structural integrity of the carton may be imparted by repeated folding over of the walls, to achieve multiple overlapping thickness and collectively a stiff upstanding peripheral πm - whilst the floor need still only be a single thickness or layer, admitting construction from a single integral sheet.

The thickness or overlapping depth of the walls can be varied with the panel arrangement. Thus, for stronger walls, more panels can be incorporated.

Thus supplementary panels may be appended to the side walls, to create (even more) multiple overlapping layers.

In a particular construction, the panel representing a carton base is again disposed at the centre of the flat array of wall panels.

The wall panels may be disposed in a linear array, le in a long strip, so that the panels are 'rolled' over on to one another.

Alternatively, the panels may be arranged for a combination of inward folding of side panels and such linear strip 'rolling'.

Two or more of the side walls have flaps extending from the sides of the folded multiple layer walls. These flaps are folded at right angles to the wall and fit between the folds of the adjacent wall.

Integrated handles penetrate the multiple layer walls incorporating the flaps extending from the adjacent walls, thus maintaining the generally perpendicular disposition of said adjacent walls.

Since the walls comprise multiple overlapping layers, the multiplicity and spacing or depth of the intervening folds required will vary.

Thus, one layer may be folded directly over to lie facing an adjoining layer, possibly with a marginal gap left therebetween to accommodate insertion of an additional layer, as a locking tab

Cartons may be constructed from a single sheet, or, to free carton size limitations from sheet size limitations, from multiple overlaid sheets to construct larger cartons.

In such multiple sheet arrangements, each sheet could form some or all of a base and wall portions

For a multiple sheet carton, the integral handle as described above serves not only to maintain the relative positions of overlapping panels, but may also hold together the multiple separate sheets

On occasion, it is desirable for a carton to have a lid - to protect or restrain the contents, and help preserve the carton s overall structural strength, rigidity and integrity

For ease of use, a carton with an integral lid is desirable.

According to a further aspect of the invention, a carton is fabπcated from sheet material, incorporating a plurality of cuts and folds, to achieve an assembled form, with a peripheral wall, upstanding from a base, the relative disposition of overlying layers in the wall being maintained by an integral handle fastening, and lid panel(s), extending from wall portιon(s), with edge retention flaps, for location alongside adjacent walls, upon lid closure.

The lιd(s) may comprise a single layer of sheet material, as extensιon(s) of the side wall(s)

The lid panels may extend from single layer side walls. In such a configuration, the strength, rigidity and structural integrity of the carton is imparted by the remaining side walls comprising multiple overlying folded layers.

The closed lid also contributes additional strength and structural integrity.

Additional panels may also be added to the side walls with lid panels to create multiple overlying folded layers. The arrangement and folding of the extra panels result in the lid panel extending from the upper edge of the side wall.

Conveniently, lid retention flaps are located within the erected carton structure when the lid panel is folded over the otherwise open carton top face.

The lid panel flaps edges may be profiled for a smooth lid opening and closing action

Additional, (say, latch or tab) fastenings may be included to hold the lid securely closed.

Alternatively, the flaps could interact with integral handle elements formed in one or more the multi-layer side walls.

In order to reinforce the assembled carton and to facilitate stacking and help withstand and distribute attendant stacking loads, supplementary individual discrete corner fittings may be employed at each corner of the carton mouth, alongside the lid

Optionally, the shapes of the panels forming two opposite sides of the box may be modified to create a so-called 'archive' box or 'suspension' filing tray.

Diagonal cuts are formed at what will be the upper edge of the outermost layer of the wall, to create a shorter panel or layer. The size and shape of further panels of that wall are modified accordingly.

Such archive boxes are used for storage of suspension file folders, in particular those with protruding arms. These arms engage the lowered side edges and thus suspend the files within the box.

The lowered edges prevent the protruding arms from being higher than the upper edge of

the carton, allowing for a lid and stacking

There now follows a description of some particular embodiments of the invention, by way of example only, with reference to the accompanying diagrammatic and schematic drawings, in which:

Figures 1 A through 1 H show progressive stages of assembly of the basic carton into an assembled carton configuration;

Figures 2A through 2F show progressive stages of folding into a compact 'wallet' configuration;

Figures 3A through 3E show detail of an integral handle and combined fastening;

Figures 4A through 4H show progressive stages of assembly of a carton with additional panels for forming multiple overlying layers;

Figures 5A and 5B show a modification of the carton shown in Figures 4A through 4H, with curved edge flaps to facilitate collapse of one side wall;

Figure 6A through 6G show a further variant of the carton shown in Figures 4A through 4H, with a shallow multi-layer reinforcement rim,

Figures 7A through 71 show progressive stages of assembly of cooperatively interfitted multiple (two in this instance) individual sheets, to allow a larger overall assembly or structure;

Figures 8A through 8M show progressive stages of assembly of a carton variant with integrated lid into an assembled carton configuration;

Figure 9A and 9B show an alternative carton variant with integrated lid;

Figures 10A through 101 show progressive stages of assembly of an 'archive' box or filing tray carton variant, with two lowered side walls;

Figures 11 A through 11 F show views of a cornerpiece and its attachment to the carton shown

in Figure 8L.

Figures 12A through 12F show the progressive stages of assembly of a discrete lid structure, based upon the constructional principle of the carton variants described above.

Referring to Figures 1 A through 1 H, a carton is constructed from a flat shape or 'carton blank' cut out of a sheet of material, such as cardboard or corrugated synthetic plastics, as indicated in Figure 1A.

The flat shape 10 is subdivided into a series of contiguous rectangular panels, with intervening creases 41 , 42, 43, 44, 45 about which the material is folded.

Each panel is attached to one or more other panels, along one or more of its four side edges.

A central panel 11 in the unfolded configuration will constitute the base or floor of the folded carton.

Along each of this base panel's four edges is attached a wall panel, namely side wall panels 12 and end wall panels 14.

Side wall flap panels 15 and 16 extend from opposite side edges of panel 12.

The end wall panel 14 has a profiled aperture 22, for an integrated handle or hand-hold feature as discussed earlier.

Side wall flap panels 15 have corresponding apertures 21 , positioned to align (with aperture 21 ) in the assembled configuration.

Side wall flap panel 16 has an aperture 23, which is aligned with the other apertures in the erected configuration, but which is somewhat wider.

The aperture 23 also carries on one side edge a hinged profiled (handle) flap 24 with protruding tabs 25.

The side walls of the assembled structure are initially erected by folding the side wall panels

12, so that they stand upright and generally perpendicular to the base panel 11

The end wall panels 14 are then folded, so that they too are upright and perpendicular to the base 11

The side wall flap panels 15 are turned inwards by ninety degrees, so that they lie parallel to - and to the outside of - the end wall panels 14

The side wall flap panels 16 are also folded by ninety degrees, to form the outside layer of the end walls

In order to secure the three layers of the end walls in their correct relative positions, the handle flap 24 in panel 16 is folded at the crease 47 - and pushed inwards through the mutually aligned apertures 22 and 21 in panels 14 and 15

As the handle flap 24 is pushed through the apertures, the protruding tabs 25 are deflected, folding at the crease 48

Once through these wall layers, the tabs 25 revert to their protruding position, and abut the inner side wall panels, the tabs preventing the handle flap 24 from returning through the apertures Thus panels 14, 15 and 16 are held in place

Figures 2A through 2F show folding of the flat sheet into a compact folded 'wallet' configuration

Starting from the unfolded configuration, illustrated in Figure 1A, the side wall flap panels 15, 16 are folded over on to their adjacent side wall panels 12

The end wall panels 14 are folded on to the base panel 11

The two sets of folded panels 12 and 15 are then folded on to the stacked panels 1 1 and 14, creating a compact folded 'wallet' configuration

The entire folded carton is thus compacted into the area of the base panel 11 , with a depth of several layers

To hold the carton in the folded 'wallet' configuration, a proprietary (eg press-stud) fastener (not shown) with mterfitting elements may be attached to the side wall panels 12, positioned so that they are aligned in the folded 'wallet' configuration

If the dimensions of the panels are such that the folded panels 16 lie between the fastener portions, it will be necessary to give these panels shaped corners to expose the fastener portions.

To assist folding, the plastics material is creased, for example by locally crushing or scoring.

To construct the assembled configuration, the adjacent panels are folded by ninety degrees, and the creases or folding spines between multiple spaced creases must be wide enough to accommodate this.

However, in order also to fold the flat shape into the folded 'wallet' configuration, the panels must lie flat - and this requires wider creases to allow for the combined width of the layers.

Creases 41 , 42 and 43 are wide enough to allow the adjacent panels to lie flat upon one another, and so must accommodate two layers of material

Crease 44 must be wide enough to allow panels 15, 16 and 12 to be folded over and to lie flat against panels 14 and 11 , thus accommodating four thickness of material.

Finally, the other set of panels 15. 16 and 12 are all folded over to lie parallel to all of the other folded panels. The crease 45 must therefore span six layers of material The presence of creases of appropriate widths will allow the folded configuration to lie as flat and thus be as compact as possible.

Figures 3A through 3E show an integral handle and fastening mechanism of Figures 1 A through 1 H in greater detail.

Referring to the Figures 4A through 4H, a carton with additional panels for forming walls (reinforced) with multiple overlaying layers is fabricated from a flat shape or carton blank' 110 - cut out of a sheet of material, such as cardboard or corrugated synthetic plastics, as indicated in Figure 4A.

The flat shape is subdivided into a series of contiguous rectangular panels 111 through 117, with intervening creases at and about which the material will be folded

Each panel is attached to one or more others, along one or more of its four side edges.

A central panel 1 1 1 constitutes the base or floor of the assembled carton 140 This base panel 111 has further panels 112, 1 16 adjoining each of its four sides.

The panels 112, 1 13 and 114 are folded together to form individual side walls of the assembled carton 140, whilst panels 115, 116 and 117 are interfolded to form end wails.

The side walls are constructed, firstly by folding the panels 1 14 inwards, to lie on top of the panels 1 13, as shown in Figure 4B

The consequent double thickness layers are then folded over to lie upon panels 1 12. The flaps 115 remain projecting from on either side of the folded wall, as illustrated in Figure 4C.

The two folded side walls are stood upright, so that they are generally perpendicular to the base panel 11 1

The flaps 115 are then turned inwards to lie square to the side walls and along the side edges of the base panel 1 11

The carton end walls are constructed by folding panels 1 16 to lie perpendicular to the base panel 111

The flaps 115 lie adjacent the inside of the panels 116, and panels 1 17 are folded over to trap the flaps 115.

A double fold 143 between panels 113 and 114 provides an intervening 'spine', of depth equivalent to double the material thickness, so that these panels 113, 1 14 may lie flat over one another without stretching the spine.

Similarly, a 'triple-depth' spine fold 142 is provided between panels 112 and 1 13 to accommodate the combined depth of two material layers formed by folding panels 1 13, 114 over one another, along with the depth of panel 112.

Fold 141 between panels 111 and 112 are (just) sufficient to allow the panels to be folded at right angles to one another.

This also applies to fold 144 between the panels 112 and 1 15. as the flaps 115 are returned to lie at right angles to the panels 1 12 - in order to fit in between the side panels 116 and 117

Folds 145 between the base panel 1 1 1 and opposite side panels 116 are again (just) sufficient to allow the panels 111 and 116 lie at right angles to one another

Folds 146, between panels 1 16 and 117 are 'triple' folds, to accommodate the intervening flaps 115.

Overall, the combined side wall depth of the assembled carton 140 is of triple thickness - for example panels 112, 1 13 and 1 14 on the one hand and panels 1 15, 116 and 11 on the other hand.

The additional layers lie within the embrace of the outer panels 112 and 116, which are contiguous with the base 1 11

The widths of the panels 113, 114 may be marginally less than those of panels 111 , 121 , to create slots 131 between the panels 113, 114 and the panels 1 15, 116, to accommodate the panels 1 17.

The panel 117 is a tight interference fit Detween the inside faces of the opposing side wall panels 113 - at the slot 131 - and so cannot readily be withdrawn or dislodged.

An integral handle secures the layers of the end wall in their correct relative positions.

The end wall panel 1 17 has a profiled aperture 122.

Panels 115 have corresponding apertures 121 , positioned to align with aperture 122 in the end wall panel 117 in the assembled configuration.

Panel 116 has an aperture 123 which is also aligned with the other apertures in the erected configuration, but which is somewhat wider.

The aperture 123 also carries on one side edge a hinged profiled handle flap 124 with protruding tabs 125

The handle flap 124 in the panel 116 is folded at the crease 147 and pushed inwards through the mutually aligned apertures 121 and 122 in panels 115 and 117

As the handle flap 124 is pushed through the apertures, the protruding tabs 125 are deflected, folding at the crease 148

Once through these wall layers, the tabs 125 revert to their protruding position, and abut the inner side wall panels 1 17, thus preventing the handle flap 124 from returning through the apertures

Additional reinforcement or stiffening layers may be added to the walls by incorporating further panels in the carton blank

Figures 5A and 5B show a carton variant adapted to enable one of the side walls to be opened, for ease of access to contents.

Side wall flap panel 231 has a smoothly curved upper edge profile 232, to allow the panel to simply be slid out from between the multiple layers of the end wall, with minimal resistance.

Proprietary (eg press-stud) fasteners 251 can be fitted at strategic locations on the carton, penetrating the multiple layers, to help prevent this carton variant from unravelling

Figures 6A through 6G show a variation in depth of peripheral wall upper edge reinforcement rim, by adapting the outermost panel dimensions and otherwise correspond generally to the embodiment of Figures 4A through 4H.

The same reference numerals are used for equivalent elements - and so Figures 6A through 6G will not be described in further detail

It should however be appreciated that varying the πm thickness could allow a larger overall structure from a given sheet size.

Figures 7A through 71 depict another carton variant with multiple inter-fitting individual sheets

320, 321 - to allow a greater overall assembled carton size.

Figure 7A shows a sheet 320 with a base panel 310 with end panels 316, 317.

Another sheet, shown in Figure 7B, has a base panel 311 and side panels 312 and 313 with side wall panel flaps 315.

In Figures 7B through 7H, flaps 315 are illustrated with a curved profile, but they may also be squared off

Figure 7C shows the sheet 320, 321 juxta-positioned so that the respective base 310, 311 panels are superimposed, one on top of the other, and respective side panels 312, 313 and 316, 317 are orientated to lie mutually at right angles

Assembled carton end walls are constructed by folding panel 312, so that it is upright to the base 310, 311 - whereupon panel 31 1 is folded over inwardly to lie flat against panel 312, as shown in Figure 7F

Figure 7E and 7F show the flaps 315 are folded at right angles to the panels 312, to lie long the side edges of the base panels 310, 311

Side walls are constructed by folding panels 306 to lie upright to the base panels 310, 311 , and adjacent the flaps 315.

Panels 317 are then folded over panels 316 to sandwich the flaps 315 therebetween

Integral handle apertures and flap(s) as illustrated in Figure 3B and 3D hold the multiple layers of the walls in their correct relative dispositions.

Referring to Figures 8A through 8 , a carton 440 with integral lid elements is fabricated from a flat shape or 'carton blank' 410 - cut out of sheet material - and progressively folded, as indicated in Figures 8A through 8L.

The assembled carton 440 is shown in Figure 8L, and features two opposed multi-layer walis - alternating with two opposed, single-layer walls - with 'hinged' lid panels 453 extending from their upper edges.

Correct relative positioning of the multiple (overlying) layers 415, 416, 417 constituting the (thicker) wall is preserved by a multiple aligned hand-hold or handle aperture and locating flap configuration, shown in greater detail in Figure 8M

Each layer 415, 416, 417 has a handle aperture, aligned in the folded configuration, to form a profiled aperture for use as a carry handle.

The innermost layers in the folded configuration, 415, 417 have similar apertures 421 , 422.

The outer layer 416 has a marginally wider aperture 423 The aperture 423 carries on one side edge a hinged profiled handle flap 424 with protruding tabs 425

In the assembled configuration, the handle flap 424 is folded inwards along fold 447 and pushed through the aligned handle apertures 421 , 422

The tabs 425 are deflected along creases 448 to fit through the marginally narrower apertures of the other layers.

The handle flap 424 then spans the width of the wall and protrudes into the carton 440

The tabs 425 on the handle flap 424 revert to lying substantially in the same plane as the rest of the handle flap 424, and span beyond the adjacent handle apertures 421 , 422.

The tabs 425 thus inhibit spontaneous return or 'spring-back' of the handle flap 424 to its original position, co-planar with outer layer 416

The lid overall comprises two opposed hinged lid panels 453, contiguous with the side wall panels 412.

Extending from each side of the lid panels 453 are lid panel flaps 451.

The lid panels 453 can be folded to overlie the otherwise open face of the erected carton 440.

The lid panel flaps 451 are folded, perpendicular to the respective lid panel 453 and inside

the carton 440, parallel to and alongside the multi-layer side wall.

As the lid is closed, the flaps 451 are located between the side wall panel 417 and the tabs 425 of the handle configuration - with an interference fit holding the lid panel flaps 451 in place and the associated lid panel 453 in the closed position

Alternative size and shape lid panel flaps 451 may be used. For example, larger flaps contribute more to the overall strength, rigidity and structural stability of the carton when the lid is in the closed position - however, they may prove more awkward to manipulate.

As shown in the accompanying drawings, the exposed lid panel flap edges may be 'relief profiled to facilitate lid opening and closing

Additionally, a cut out or notch 452 on the free lid panel edge provides a finger-pull.

The carton may be reinforced, stiffened and braced by the insertion of discrete corner pieces, for example of moulded plastics. Such corner pieces could also be adapted to support and locate carton stacking - as described with reference to Figures 11 A through 1 1 F

In the embodiment of the carton with integrated lid described above, the side walls carrying the lid panel is of single thickness.

Figures 9A and 9B show an alternative embodiment of a carton with an integrated lid, wherein additional panels 413 and 414 are folded to provide a multi-layer side wall with a lid panel.

Also in this embodiment, the lid comprises a single panel Such a lid may have lid panel flaps on one or more of its three free edges.

The lid panel flaps are held in place by sliding through aligned slots in adjacent multi-layer walls, as illustrated.

Alternatively, the lid flaps could simply lie against the inner face of the erected carton wall, or be securely held in place by interacting with the integral handle using principle described above.

Referring to Figures 10A through 101, an archive carton is constructed from a flat carton blank

profile, as depicted in Figure 10A

The configuration of panels and folds follows the same principle as the cartons described above - except that the panel 512 has diagonal cuts 531 at either end of the edge between the panels 512 and 513

The fold 542 between the panels 512 and 513 is positioned between the ends of the diagonal cuts 531

Thus, when panel 513 is folded to lie parallel with panel 512, the edge 532 created at the fold 542 will slant downwards at each end - the rest of the wall being shorter than the overall height of the erected carton, as shown m Figure 101

Figures 1 1 A through 11 F show a reinforcement and stacking corner piece embodiment and its disposition for carton stacking

A corner piece 61 comprises perpendicular side walls 62, 63, braced by an inner ledge 64 with a depending inner leg 65, forming a shallow throat 67 with the side wall 62 - and with a cut-out or relief 66 at one edge to form a marginal throat 68 with the side wall 63

As an example, Figure 1 1 E shows the corner piece 61 is fitted to a corner of erected carton

440 as previously illustrated in Figure 8L

The ledge 64 rests upon the upper edge of the multi-layer carton wall

The wall is held snugly in the shallow throat 67, alongside a lid retention flap, but without interfering with the lid hinging action

The adjoining single layer wall is held snugly in the throat 68

The corner piece 61 thus helps preserve the correct relative (mutually orthogonal) positions of the adjoining carton walls, increasing the overall structural strength, rigidity and stiffness of the assembled carton 440

When fitted, the side walls 62, 63 of the corner pieces 61 extend marginally above the upper carton edge, to create collectively a shallow corner edge frame - for locating a stacked carton

440, as shown in Figure 11 F

The corner pieces 61 thus help preserve the correct relative positions or alignment of stacked cartons 440, directly above one another, reducing the risk of dislodgment, for example by casual collision.

Whilst a carton variant with an integrated lid has been described above, a removable discrete lid is also envisaged.

Figures 12A through 12F show the progressive stages of assembly and disposition of a discrete lid structure, comprising a multi-layer configuration for strength and rigidity

The base panel and reinforced multiple layer πm of the lid are configured to provide a marginal clearance fit upon the upstanding open rim of the carton

The folded configuration of the panels of the multi-layer end walls is maintained by inserting shallow tabs extending from the innermost panel in the erected configuration into slots along the crease between the base panel and the adjacent end wall panel

Desirably, the carton is fabricated from proprietary corrugated cardboard or synthetic plastics sheet, such as 'Correx' or 'Corπboard' (Trade Marks).

For economy of manufacture it is desirable to use sheet material of standard production size and to minimise wastage.

This can impose limitations on the overall carton size and configuration. It may therefore be necessary to adapt the dimensions of the panels according to the shape and size of the sheet material.

If the cartons are to be used for carriage of heavy objects, it may be desirable to stiffen or reinforce selected walls or the base in the assembled configuration to prevent deformation. This should however not be such that it interferes with the compact folded configuration of the carton.

Thus, the carton walls and interconnections may be reinforced with integrated stiffening elements, eg rods or wires, around which the panel folds and sandwiched between panels.