GB2181411A - Nestable and stackable containers - Google Patents

Abstract

A nestable box 1 of thin walled plastic material has side walls 2, 3 and transverse walls 4, 5. Platforms 15 are provided on the top of column formations 11, and foot areas 18 are provided at the base of further column formations 17. A second foot area 60 is provided at each corner of the box. The foot areas 18, 60 and platforms 15 cooperate to facilitate stacking of a 31 transversely of underlying. The base of the box has a system of downwardly projecting ribs including gapped peripheral ribs and ribs defining channels 27, 29 for engaging rims 6 of like boxes to for stable stack. <IMAGE>

Description

SPECIFICATION A nestable thin-walled box This invention relates to nestable boxes of thin-walled plastics material, which are suitable for storing and/or transporting food products, especially tender fruits and vegetables, such as mushrooms, tomatoes, plums and the like.

Rectangular boxes of thin-walled plastics material are currently used for storing and transporting mushrooms. These boxes are moulded with sloping sides so that they nest, one inside another, before they are filled.

After filling, they are placed on a pallet which has cage sides. Five boxes form a layer.

Three such boxes are built up on the pallet taking care that the boxes are oriented so that the bottom of each box rests on the upper edges of the box below it. Because of the sloping sides of the boxes, the boxes on the outside of the stack have no such support and tip into the boxes below and damage the product (in this case mushrooms). To overcome this, a metal grill is placed tightly over the third layer of boxes. This is only partially successful in limiting the tendency for the outer boxes to tip into the boxes below and can actually cause damage through excessive pressure. A further three layers of boxes are built on the metal grill and a further grill is applied. This process of stacking continues until fifteen layers of boxes, with metal grills every third layer, are caged on the pallet.The pallet, cage and grills are specially made for the transportation of the boxes in refrigerated containers and are returnable empty. This means that for every full container going out from the packing premises, an otherwise empty refrigerated container brings a load of pallet cages and grills back. Apart from the capital invested in pallet cages and grills, the inefficient use of refrigerated containers is very expensive.

The present invention provides a nestable thin-walled box having on its base formations which are adapted to interlock with the rims of like boxes so as to form a stable stack of boxes.

Conveniently, the box is rectangular in plan and includes one or more of the following features: (a) the length / width ratio is substantially 3/2 (b) formations on the bottom of the box define two transverse downwardly open chan nels at intervals of substantially 1/3 of the overall length of the box and one longitudinal downwardly-open channel at the longitudinal axis of the box, each channel having a width slightly greater than twice the thickness of the rim of the box (c) at least two support areas are provided on the top of inwardly-convex column formations in the longitudinal side wall of the box, and (d) at least one foot area is provided at the bottom of an outwardly-convex column formation in each transverse end wall of the box, the foot area being located so as to be aligned with a support area on a second box when the first-mentioned box is stacked on top of the second box with their axes at right angles to one another.

Advantageously, a second foot area is provided at each corner of the box, said second foot area being capable of being located on a support area of a second box.

Preferably there are two support areas on each side of the box, at intervals of substantially 1/3rd of the length of the box, and one foot area on each end of the box located substantially on the axis of the box.

The downwardly-open channels of boxes on one layer receive the rims of adjacent boxes in the underlying layer when the boxes are stacked. The formations which define the channels lock the adjacent boxes in the underlying layer together. These formations do not necessarily or even usually define continuous walls for the channels; at the minimum, each channel may be defined by a pair of downwardly-open slots at opposite sides or opposite ends of the box, provided that a clear path is provided between the pair of slots, and the bottom surface of the box between the pair of slots is not lower than the level of the bridge of the slots.

One embodiment of the invention is illustrated in the accompanying drawing, in which: Figure 1 is a projection of three boxes according to the invention, Figure 2 is an underneath plan view of one box according to the invention, Figure 3 is a cross section on the line A-A in Figure 2, Figure 4 is a cross section on the line B-B in Figure 2.

As shown in the drawings, a nestable box 1 of thin-walled plastics material is rectangular in plan and has longitudinal side walls 2,3 and transverse end walls 4,5. The ratio of the overall length to the overall width is 3:2; for example a box having a length of 285 mm has a width of 190 mm. The box is injection moulded, preferably using polypropylene, or alternatively high density polyethylene. The wall thickness is suitably in the range 0.5-1.0 mm, preferably about 0.75 mm. The walls are inclined to the vertical, to permit nesting.

The box has a rim 6 around its upper edge, the rim being formed by a ledge portion 7 extending outwardly from the top of the respective wall 2, 3, 4, 5, and a flange portion 8 extending downwardly from the outer edge of the ledge portion 7. Struts 9 are provided between the respective wall and the flange portion 8.

Each wall has a series of strengthening ribs 10 extending up the wall from the bottom thereof to a point below the rim. Each rim 10 is moulded as an inward bulge in the plastics material and is open at the bottom for nesting purposes. Ventilation holes 33 may be provided in the walls, if desired, at any suitable location.

Two hollow column formations (11,12; 13,14) are formed by moulding in each side wall 2,3. These side column formations are inwardly convex, are open at the bottom but have a platform 15 at the top which provides a support area level with the rim but projecting inwardly therefrom. The side column formations are spaced from each other and from the ends of the box at intervals of 1/3rd of the length of the box e.g. in a box having a length of 285 mm, the centres of the column formation are spaced by 47.5 mm from the transverse mid-line of the box. Each side column formation has a small outward inclination to the vertical (see Figure 3) so that successive boxes can be nested, one inside another, with the column formations of a lower box received in the hollow spaces in the column formations of the next box above it.

One hollow column formation (16,17) is formed by moulding in each end wall (4,5).

These end column formations (16,17) are outwardly convex, are open at the top but have a foot area 18 at the bottom which is level with the base 19 of the box but projecting outwardly therefrom. The end column formations are located on the longitudinal axis of the box.

Each end column formation has a slight inclination to the vertical (see Figure 4) so that successive boxes can be nested with the end column formation of a higher box being received in the hollow spaces in the end column formation of the next box below it.

As shown in Figure 2, the base 19 of the box has a plurality of downwardly projecting ribs 20, each moulded as a downward bulge in the plastics material and each having the same depth. Close to the perimeter of the base there is a peripheral rib system 21, which extends all the way around the base except where it is interrupted by slots 22,23, at locations corresponding to the location of the column formations 11, 12, 13, 14, 16, 17. Close to the longitudinal axis of the box there are two aligned series of longitudinal ribs 24 which are spaced apart by a distance equal to the width of end slots 22. Similarly arranged in relation to the side slots 23 there are four pairs of transverse ribs 25 spaced apart by a distance equal to the width of the slots. Additional transverse ribs 26 may also be provided, if desired.

The portions of the peripheral rib 21 which define the end slots 22, in conjunction with the longitudinal ribs 24 define a longitudinal channel 27 having a width slightly greater than twice the width of the ledge portion 7 of the rim of the box. For example when the ledge portion is 4 m wide, the channel may be 10 mm wide. Similarly, the portions of the peripheral rib 21 which define the side slots 23, in conjunction with the transverse ribs 25 define two transverse channels 28, 29 of the same width as the longitudinal channel. The position of the channels 27, 28, 29 is shown in Figure 2.

When two boxes (1,30) are placed side by side, as shown in Figure 1, a third box 31 can be placed on top of them, with its axis at right angles to the axes of the lower boxes.

One foot area 18 at the end of the upper box 31 comes to rest on one platform 15 on column 12 at the side of lower box 1, while the further of the two transverse channels 29 comes down on the adjacent rims 6 of the two lower boxes 1, 30. The two rims enter the channel 29, and the two platforms 15 on column 14 of the box 1 and column 12 of box 30 enter the gap at the junction between channels 29 and 27. The two rims of the adjacent boxes are locked together by the formations which define slots 23 and transverse ribs 25.

Box 31 covers 2/3rds of the length of box 1. When one or more additional boxes are present in the lower layer beyond the end walls 4 of boxes 1 and 30, a further box can be brought down beside box 31 in such a manner that the rims on the end walls 4 and the rim(s) of the adjacent box(es) enter a corresponding channel in the bottom of the further box and will be locked thereby. Similarly when one or more additional boxes are present in the lower layer beyond the side wall 3 of box 30, an added box can be brought down beyond box 31, and the rim on the side wall 3, together with the rim(s) of the adjacent box(es), will enter the appropriate channel in the bottom of the further box and will be locked thereby.

Each box of the upper layer rests on at least one foot area and one channel, or on two channels which are at right angles to each other, so that the boxes are held in a stable manner and do not overbalance into the lower layer. -The column formations also strengthen a stack of the boxes in layers.

When the boxes are full with the appropriate product (e.g. mushrooms) a layer of boxes is laid on a flat disposable pallet. A group of 5 boxes suitably form a layer, with three boxes side by side and two boxes laid crosswise at the ends of the three boxes. The next layer of boxes is then placed on top, with the orientation of the boxes turned through 90 so that the channels in the bottom of the upper boxes lock onto the rims of the lower boxes.

If desired, each layer may have 6 or more boxes, provided that the alternating layers of boxes can be laid over one another.

A stack of boxes can be built up in layers on the pallet without any cages or grills. If desired, corner pieces of disposable packing material can be applied to the vertical corners of the completed pallet and the stack can be bound with a tape or otherwise to add strength for transportation. No returnable item is required and the space in a transport container can therefore be filled with some other product for the return journey, leading to a substantial reduction in costs. In addition the risk of damage to the product in the boxes, due to tipping of the boxes, is eliminated.

If desired, each box may be provided with a lid, in which case the lid either fits within the rim of the box or the lid locks onto the rim of the box and is itself provided with an upstanding rim which can be interlocked by the channels in the overlying layer of boxes.

Depending on the stacking arrangement used, it is sometimes necessary for foot 60 on one box to rest on a platform 15 of an underlying box. A foot 60 is provided at each corner of the box at the end of a column formation. The construction of the feet 60 and platforms 15 provides a means for positively supporting the stacked boxes.

Claims (7)

1. A nestable thin-walled box having on its base formations which are adapted to interlock with the rims of like boxes so as to form a stable stack of boxes.

2. A box as claimed in Claim 1, in which the formations on the bottom of the box define two transverse downwardlyopen channels at intervals along the overall length of the box and one longitudinal downwardly-open channel at the longitudinal axis of the box, each channel having a width slightly greater than twice the thickness of the rim of the box.

3. A box as claimed in either Claim 1 or Claim 2, in which at least two support areas are provided on the top of first column formations in each longitudinal side wall of the box and at least one first foot area is provided at the bottom of a second column formation in each transverse end wall of the box, the foot area being located so as to be aligned with a support area on a second box when the first box is stacked on top of the second box with their axes at right angles to one another.

4. A box as claimed in Claim 3 in which a second foot area is provided at each corner of the box, the second foot area being provided at the end of a third column formation.

5. A box as claimed in any one of Claims 2 to 4 in which the length to width ratio of the box is substantially three to two, the channels are at intervals of substantially one third of the overall length of the box, two support areas are provided each side of the box at intervals of substantially one third of the length of the box, and a first foot area is at each end of the box located substantially on the axis of the box.

6. A box as claimed in any one of Claims 2 to 5 in which the downwardly-open channels are defined at the minimum by a pair of downwardly-open slots at opposite sides or ends of the box, with a clear path being provided between the pair of slots, and with the bottom surface of the box between the pair of slots being not lower than the level of the bridge of the slots.

7. A box substantially as herein described with reference to and as shown in the accompanying drawings.