Containers

This invention relates to plastic containers.

According to one aspect of the invention there is provided a plastics container comprising a base wall, a pair of side walls and a pair of end walls, wherein the walls of at least one of the said pairs of walls comprise a pair of parallel surfaces connected together and re-in-forced a pair of parallel surfaces connected together and re-in-forced by cross pieces. The container is preferably an injection moulding and the cross-pieces extend in the direction of mould movement. Thus a wall is provided which is reinforced by projections but is unencumbered by re-inforcing on both on its interior and exterior surfaces which are preferably entirely smooth. Preferably at least one of the remaining walls is reinforced but does not comprise parallel surfaces, this said wall preferably being the base wall. Preferably the side and end walls comprise parallel surfaces joined together by cross-pieces as aforedescribed. Insulation material may be inserted between the surfaces of the multi-surface walls.

One of the pairs of side and end walls preferably extends below the base wall to leave a gap below the base wall, into which gap the forks of a fork lift truck can be inserted to permit the container to be carried thereby. The walls of the other pair of walls preferably taper at the entrance to the gap to provide a lead-in surface for the forks. A high wear resistant high density polyethylene plate is preferably provided at such tapered portion to protect it. The extensions may conveniently be formed separately and inserted between the surfaces.

The container is conveniently provided with a lid. This lid preferably has an interior rim which fits within the side and end walls. The inner surface of the rim is preferably radiussed to provide a rounded corner for ease of cleaning. The lid is preferably a double surface wall which is closed at its edges and which has cross-ribs extending between the surfaces. These surfaces are preferably separately formed by injection moulding and then by heating the ends of the cross-ribs and edges softening these and forcing the surfaces together so that the ribs seal. The lid is preferably welded to the end and side walls of the container.

The lid conveniently has an enlarged opening therein. An inlet feed member is preferably received into the opening preferably by being screw threaded therein. The feed member preferably has a filling opening with a filling plug closing this opening. A vent valve may also be provided in the feed member. The size of the opening is preferably such that there is access to the interior of the container for cleaning purposes.

At the upper side of its corners, the lid may be provided with frusto-conical projections to provide locating means for a second container placed thereon. The projections are preferably internally cored to receive an eye which may be engaged by a hook for lifting purposes. Below the projections, the lid may have locating means that engage in recesses in the walls.

The base of the container is preferably provided with an outlet opening which is preferably located near to one of the other walls and the base wall preferably slopes towards the outer opening. Within the opening there may be received the inlet member of an angled elbow connection to permit liquid contents of the container to be delivered outside the envelope of the container.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings.

In the drawings:

FIG. 1 is an outside view of a container of the invention,

FIG. 2 is a transverse section through the container,

FIG. 3 is a detail section through the feet of the container, and

FIG. 4 is a detail section on line 4--4 of FIG. 1.

Referring now to the drawings, there is shown a container 10 of the invention. The container is formed as a plastics injection moulding. The container 10 which is parallelipipedal in shape comprises a body 12 and a lid (described below). The body 12 comprises a base wall 16, a pair of opposite side walls 18 and a pair of opposite end walls 20.

The side and end walls 18 and 20 are each comprised by a pair of spaced parallel surface members 22 and 24 which are connected together by cross-pieces 26 and which are open at their lower ends. The cross-pieces 26 extend vertically from the base wall 16, i.e. in the direction of mould movement during the moulding of the container. Thus the side and end walls are of double wall construction reinforced by the cross-pieces 26. Furthermore the interior and exterior surfaces of each of the double walls is smooth. The base wall 16 is also re-inforced by projection walls 16a arranged in a mesh-like formation as is known in the art.

At their junctions, the side and end walls and the base walls are heavily radiused for ease of cleaning.

The base wall 16 has an outlet opening 28 which is located near to one side 18 about midway between the end walls 20. The base wall 16 slopes towards this outlet opening 28. A plug 29 normally closes this opening 28.

An angled elbow connection 30 (shown in chain lines) may be inserted into the opening 28 for delivering the contents of the container is provided. The connection 30 has a vertical inlet member 31 that is received within the outlet opening 28, a long delivery arm 32 including a closure cock 34, and a delivery spout 36. The connection 30 can thus permit liquid contents of the container to be delivered outside the envelope of the container. (Although the connection 30 is shown projecting inwardly of the container, it can be, and usually is arranged projecting outwardly.)

At their lower ends, the end walls 20 receive rigid feet 38 on which the container rests to leave a gap 40 below the base wall 16. Each foot 38 comprises an upstanding leg 42 that fits between the lower portion of the surface members 22 and 24 and has at locations along its length a pair of projections which fit into corresponding openings in the outer surface members 22. Thus each foot 38 is firmly held in position. Each foot 38 also has a pair of openings 44 to receive the forks of a forklift truck under certain circumstances which will be discussed below.

At the entrance to the gap 40, the projection walls 16a on the base wall 16 are of decreasing length. There is thus formed a lead-in portion 46, which is up to 50% larger than the remainder of the gap 40, to serve to facilitate and guide the entry of the forks into the gap 40. A high-wear-resistant polypropalene plate 48 is provided at such lead-in portion to protect it. The plate 48 has projections on its upper surface that fit firmly in between the projection walls of the base wall thereby holding the plate 48 firmly in position.

The upper end of the container 10 is closed by a lid 50 which is welded to the end and side walls of the container. The lid 50 has a pair of surface walls 52 and 54 which are closed at their edges 54 and which have cross-ribs 58 extending therebetween. These surfaces 52 and 54 are separately formed by injection moulding each to have portions of the cross-ribs 58 integral with it. After the surfaces 52 and 54 are thus formed, the ends of the cross-ribs 58 and the edges 60 are heated to soften them. The surfaces 52 and 54 are then forced together so that the ends of the ribs 58 and edges 54 seal with one another to form an integral unit.

On its underside, the lid 50 has a peripheral recess 64 so that the lid body fits closely within the side and end walls 18 and 20. The inner surface 66 of the rim 64 is heavily radiused to provide a rounded corner for ease of cleaning.

The lid 50 has an enlarged aperture 68 therein. The size of the opening is preferably such that there is access to the interior of the container for cleaning purposes. A closure member 70 is threadedly received into the aperture 68. The inlet member 70 incorporates a filling opening 72 with a filling plug 74 threadedly received therein to close this opening 72. A vent valve 76 is also provided in the closure member 70.

At the upper side of its corners, the lid 50 has low wide frusto-conical projections 78. A bore (not shown) is formed in each such projection 78 to receive a lifting eye 80 which may be engaged by a hook for lifting purposes. Below the projections 78, the lid 50 has a recess which engages on a projection at junctions between the side and end walls for additional locating of the lid on the container.

The container can be easily lifted by a fork-lift truck with the forks passing through the openings in the feet. If it is desired to tip the container for any purpose, the forks can be passed through the openings 44 in the feet 38 so that there is a firm connection therebetween.

The container 10 as above described may be of any convenient size which may range from two hundred liters to fifteen hundred liters. Because of the double surface construction, the side and end walls will be rigid and will not bulge when the container is filled with liquid. Furthermore, a degree of insulation is achieved with the air gap and may be supplemented by inserting between the walls foam or other insulating material (indicated at 82 in FIG. 4). Because of its cuboidal form, the container provides a very efficient containment for liquids.

The invention is not limited to the precise constructional details hereinbefore described and illustrated in the drawings.

It is to be noted that in this specification the term "parallel" is used in to include in its meaning "near parallel" as many parts have a small taper (normally of the order of 4.degree.) to facilitate demoulding.