GB2265706A

GB2265706A - Insulated containers

Info

Publication number: GB2265706A
Application number: GB9305308A
Authority: GB
Inventors: Victor George Davis
Original assignee: STYROPACK
Current assignee: STYROPACK
Priority date: 1992-04-01
Filing date: 1993-03-15
Publication date: 1993-10-06
Also published as: GB9305308D0

Abstract

An insulated container (1) having a foamed core and an impervious skin (10) and comprising a base (2) and an upstanding peripheral sidewall (3, 4), the upper edge (7e, 7c, 8) of the sidewall (3, 4) and the underside (9) of the periphery of the base having complementary engaging formations (9, 7c, 7e, 8). <IMAGE>

Description

INSULATED CONTAINERS The present invention relates to containers, and is particularly concerned with stackable thermally insulated trays for the transport of foodstuffs.

Currently, foodstuffs, particularly bakery products are conventionally transported in trays each containing a single layer of bakery products, since these are generally of such a fragile nature as not to permit piling. In order to transport bakery products containing cream, confectioner's custard, or the like, it is necessary to refrigerate such products to maintain them at a temperature below a predetermined limit. Currently available bakery trays are unsuited to maintain chill temperatures without the use of refrigerated transport for such products, since the trays are neither insulated, nor do they provide effective sealing between trays piled one on top of another, thus allowing heat transfer between the foodstuffs and the surroundings.

The present invention seeks to provide a tray of insulated construction, usable for the transport of foodstuffs where temperature control is necessary.

According to the present invention, an insulated container comprises an insulated base having a peripheral upstanding insulated side wall, the upper edge of the side wall being formed with a rebate capable of cooperating with a corresponding rebate extending round the periphery of the underside of the base of a second, identical tray.

Preferably, the configurations of the cooperating rebates are such that the free edge of a side wall may cooperate with the underside of the base of a tray, or the free edge of the side wall may cooperate with the free edge of the side wall of a second tray.

This facility will allow trays to be stacked either in an array where all the trays are in the same orientation, or alternatively in an array where at least one of the trays is in an inverted orientation, and mates with the tray next below it in the stack to provide an enclosure for food products whose height would otherwise exceed the height of the side wall of a tray.

An embodiment of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a bakery tray; Figure 2 is a partial sectional view of the side wall and base of the tray of Figure 1, taken along section line II-II; and Figure 3 is a partial sectional view of the side wall and base of a tray taken along the line III-III of Figure 1.

As can be seen in the drawings, the bakery tray 1 comprises a rectangular base 2 having a width substantially half its length, and having an upstanding side wall comprising a pair of longitudinal side walls 3 and a pair of transverse side walls 4 extending about the periphery of the base 2. The height of the sidewalls is approximately a quarter of the width of the base. The most preferred ration of length to width to height is 1000 : 600 : 112.

At two diagonally opposed corner regions 5 and 6 of the side walls, an external rebate 7e is formed to extend from the mid point of one of the longer side walls 3, round the corner regions 5 and 6, to the mid point of the adjacent transverse side wall 4. At the remaining corner regions, an internal rebate 7i is formed so as to extend between the mid points of adjacent sides. Thus, in the corner regions 5 and 6 an external step is formed in the upper edge of the side walls, and at the remaining corner regions an internal step is formed. This configuration will allow a second tray, identical to the tray shown in Figure 1 to be inverted and placed on top of the tray shown, with the rebates 7e, 7i on the upper edges of the side walls 3 and 4 interlocking to locate the two trays firmly together.

On the underside of the base of the tray, vertically below each of the cutaway rebates 7e, 7i in the side walls 3 and 4, a downwardly extending ridge 9 is formed. At the corner regions corresponding to regions 5 and 6 of the tray, the ridge 9 extends at the periphery of the tray. In the remaining two corner regions, the ridge 9 is spaced inwardly from the periphery of the tray, by a distance substantially equal to half the thickness of the side walls 3 and 4. This configuration allows the ridges 9 to cooperate with the rebated areas 7e and 7i of the upper edges of the side walls, when two trays are placed one on top of the other.

The trays are preferably formed as integral mouldings of expanded polystyrene or polypropylene, and are coated with an impervious outer layer 10 to provide a non-porous outer surface. The coating is preferably a water-based polyurethane coating, or may be an epoxy resin or vinyl composition. The preferred combination of materials is an epoxy resin coating for the interior of the tray, and a water-based polyurethane coating for the exterior of the tray.

In the transverse side walls 4 of the tray 1, cutouts are provided for ease of handling. The cutouts also serve to indicate to an observer the orientation of each individual tray in a stack, so that an inverted tray which is acting as a lid for the tray below it is easily recognisable, and operatives handling the stack of trays will refrain from separating these two trays unnecessarily. The side walls 3 and 4 of the trays may also include indicia indicating the orientation of each tray, such as a proprietary name, or other formation. The indicia may be printed onto the tray, or may comprise moulded-in depressions or protrusions from the side walls 3 and 4.

The tray of the present invention is preferably formed by first injection moulding a foam core from expanded polystyrene or polypropylene, and thereafter applying the coating materials to the preformed core in order to complete the tray.

In a preferred embodiment, the preformed core is provided with a number of recesses each of which can receive a metallic or magnetic insert, so that by placing inserts in some, all, or none of the recesses prior to the application of the coating layer, an individual identifying code can be built into the tray. Since the coating material completely covers the inserts, the identifying code is not readily apparent to a casual observer of the tray, but can be read by passing a conventional metal detector or induction coil over the area containing the inserts. The inserts may be arranged as a number of metal strips arranged in a row rather like a conventional 'bar code' or may comprise metal discs arranged in a linear or circular array. The code will be read by drawing a detector along or around the array in order to detect each of the metal inserts forming the identification code.

As an alternative to forming the impervious outer surface of the tray by coating a flowable material on to the core, the outer skin may be formed by a preformed rigid plastics shell made in two halves and assembled round the foamed core. Preferably such a shell is formed from ABS polymer or high-impact styrene, and comprises an inner shell half forming the interior walls of the tray and extending over the upstanding sidewalls to terminate at approximately their mid-height. An outer shell half forms the underside of the tray and extends up the exterior of the side walls to overlap with the inner shell half, the inner shell half preferably extending outward of the outer shell half in the overlapped region. To seal the halves together, the overlapped portions may be welded or bonded together, or an adhesive plastics, such as for example polypropylene, tape may be applied over the join.

Such a construction can still be used with the metallic inserts placed in the foam core as previously described, but has the advantage of increased durability and resistance to low temperatures such as are encountered in blast freezing techniques.

Claims

1. An insulated container comprising a base wall and an upstanding peripheral sidewall formed from an insulating core material with an impervious outer layer, the upper edge of the sidewall and the periphery of the underside of the base being formed with identical complementary interengaging formations so arranged that the upper edge of the sidewall of a first container can engage with the underside of the base of a second container, or with the upper edge of the sidewall of a second container.

2. An insulated container according to Claim 1, wherein the core material is foamed polystyrene or polypropylene.

3. An insulated container according to Claim 1, wherein the impervious outer layer is applied as a coating in liquid form.

4. An insulated container according to Claim 1 or Claim 2, wherein the impervious outer layer is formed as two half shells and is assembled about the core.

5. An insulated container according to any preceding Claim, wherein the core is formed with a number of cavities to accept metallic or magnetic inserts.

6. An insulated container according to any preceding Claim, wherein the base is rectangular and has a length to width ratio of approximately 10 : 6, and the height of the sidewall is approximately one fifth of the width of the base.

7. An insulated container substantially as described herein with reference to Figures 1 to 3 of the accompanying drawings.