GB2200339A

GB2200339A - Nestable containers

Info

Publication number: GB2200339A
Application number: GB08701954A
Authority: GB
Inventors: Gerald Ivor Robinson
Original assignee: DOLPHIN PACKAGING MATERIALS
Current assignee: DOLPHIN PACKAGING MATERIALS
Priority date: 1987-01-29
Filing date: 1987-01-29
Publication date: 1988-08-03
Also published as: GB8701954D0

Abstract

A container formed from thin plastics sheet has a container body and an out-turned rim 10. The upperside of the rim 10 has a plurality of abutment surfaces 22, 24 and the underside of the rim 10 has at least one bearing surface 12. The surfaces 12, 22, 24 are so arranged that, when the containers are stacked with the abutment surfaces 22, 24 on a lower container engaging the bearing surfaces 12 on an upper container, complete nesting of the containers is prevented to prevent jamming. In such a nested stack, the containers are preferably reversed relative to those adjacent. <IMAGE>

Description

Containers This invention relates to containers.

Containers for packaging are well-known and a great number of these are of the type formed from plastics sheet material suitably, although not necessarily, by the vacuum-forming process. Such a manufacturing method generally involves feeding a web of plastics material to a heat source to cause it to become pliable, and then locating over a mould of the desired shape. A vacuum supply is then activated and this causes the pliable material to be sucked down onto the mould where it is rapidly chilled. Next, the formed plastics material is parted from the mould, cut into the required outline shape if necessary, and stacked ready for transport to the customer. The containers nest within each other conveniently for packing and transporting.

Because of the nesting of the containers, the workforce concerned with filling the containers with the saleable products, e.g. foodstuffs and the like, often have difficulty in separating them from the stack, particularly if pressure has been applied during transportation or in the actual stacking operation.

This invention seeks to provide such a container which is readily separable from a stack of such containers, and a method of manufacturing and stacking containers of that type.

According to this invention we provide a container of formed sheet plastics material comprising a container body and an outtuined rim, the upperside of said rim having a plurality of abutment faces and the underside of said rim having at least one bearing surface, the abutment faces and at least one bearing surface being positioned so that, when a like container is stacked thereon or thereunder the abutment faces of one container contact the at least one bearing surface of the other container to prevent complete nesting of the containers one within the other.

In one form of the invention the abutment faces are formed by lands extending inwardly from the uppermost face of the rim. Preferably, for a container having four side walls, lands (preferably two) are provided on the rim of one of a first pair of opposite side walls and preferably a land is also provided on the rim of each of the second pair of opposite side walls towards the ends of those side walls distant from that side wall of the f-irst pair having lands. In such a construction, when several identical containers are stacked one within the other, with each alternate container rotated horizontally through 1800 with respect to the previous container, the lands of adjacent containers do not overlie each other, but instead, lands of one container are free to contact a bearing surface on the underside of the rim of an adjacent container so as to prevent complete nesting therein.

In an alternative form of the invention, the abutment faces are formed by inwardly extending shoulders in the region of corners of the container rims, the shoulders projecting inwardly from the rim at both corners on one of a first pair of opposite side walls and inwardly from the rim of each of the other pair of opposite side walls at that corner distant from the said one of the first pair of side walls. In this construction also, when several indentical containers are stacked one within the other, with alternate containers rotated horizontally through 1800 with respect ta the previous container, the shoulders aof adjacent containers will not overlie each other and the shoulders of one container will contact a bearing surface on the underside of the rim of an adjacent container.

Therefore according to a further aspect of this invention we provide a stack of like containers as defined above, each member of the stack being of a conformation which is reversed with respect to the adjacent container, the abutment faces of one container contacting the at least one bearing surface of the adjacent container positioned thereon.

Such stacks have the advantage that the containers are not tightly nested one within the other and it is possible to remove each container from the stack for filling at a filling station without difficulty.

The invention also provides a method of providing such a stack of containers, comprising forming sheet plastics material into a plurality of joined container forms, each container form having the container construction defined above, but each container form having a conformation which is reversed with respect to the adjacent container forms, severing the container forms and feeding them, with alternate conformation, to a stacking mechanism. she stacking mechanism preferably comprises a loading station receiving each container in turn from a horizontal feed, and subsequently lifting said container onto the bottom of a stack of containers held by suitable suspension means.

The invention will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 is a plan view of one embodiment of the invention; Figure 2 is a front elevation of the container shown in Figure 1, parts being broken away and in section on the line II - II of Figure 1.

Figure 3 is a scrap view of part of a stack of containers, shown in section; Figure 4 is a view of series of four such containers during the manufacturing process; Figure 5 is a diagrammatic view of a stacking mechanism in operation; Figure 6 is a plan view of an alternative embodiment of the invention; Figure 7 is a section on the line VII - VII of Figure 6; and Figure 8 is a plan view, similar to Figure 4, but of the embodiment of Figure 6.

As seen from Figures 1 and 2, a vacuum-formed container 2 according to a first embodiment of the invention comprises upstanding side walls 4 and upstanding end walls 6A and 6B, a base 8, and a rim 10 formed around the upper part of the upstanding side walls and end walls as follows. Considering firstly the left-hand end wall 6A, as seen in Figure 2, the upper part of the wall is turned outwardly to from a shoulder 12 and then upwardly to form a short wall 14 which is then turned outwardly again to provide a flat surface 16-before being turned downwardly at 18 and outwardly once more at 20. This formation of a rim on a vacuum-formed box-like container is known and provides a comparatively rigid frame at the top of the box.

If all the containers of a stack have such a rim construction as described for end wall 6A, when nested within each other, the outer surface of the wall 14 of one container fits snugly against the inner surface of the wall 14 of the next following container in the stack.

Similarly, the inner surface of the portion 18 fits snugly against the outer portion 18 of the outer container. This fitting of one rim within the next rim causes the stack of containers to jam together in such a way that they are difficult to separate. This is what has been found to happen in practice with stacks of containers according to the prior art.

In accordance with the present invention, in order to avoid such jamming together, the rim 10 of the container is provided at certain locations with abutment faces 22, 24. As seen particularly well in Figure 1, the abutment faces 22 are located on two of the longer sides of the container rim adjacent sides 4, and the abutment faces 24 are located on one of the shorter sides of the rim adjacent end wall 6B. These abutment faces 22, 24 are formed by interrupting the shoulder 12 and short wall 14 with inwardly extending lands having an inner face 23 which is in the plane of the adjacent wall 4 or 6B, which face 23 then turns outwardly to give abutment faces 22, 24 in the plane of flat surface 16.

When the containers 2 are collated into a stack as shown in Figure 3, each alternate container of the stack is located with its end wall 6A lying adjacent the end wall 6B of the container next in the stack. It will be seen that, by this arrangement, the shoulder 12 at the short side 6A of one container is supported on the abutment face 24 on the side 6B of the next following container in the stack. Likewise, the continuation of the shoulder 12, which lies along the longer sides 4 of the container, is supported at each side of the abutment faces 22. In this way it is found that the containers do not jam one within another and they are consequently readily separable.

In the embodiment illustrated in Figures 6 and 7, instead of forming abutment surfaces 22, 24 as the top faces of short upstanding formations in the rim as in the first embodiment, shoulders 112, 114 eachof which has varying width, are formed at the corners of the container.

As shown in Figure 6, that shoulder 112 which extends from the inner face of the rim 110 to the near vertical wall of the container varies, in the case of the left-hand side of the container, from a substantial width down to a comparatively narrow width as one moves from the shorter to the longer sides of the container. Thus, in plan, the radius R3 of the side wall of the container, and the outer radius R2 of the rim 110 are both struck from the fulcrum point A, whereas the inner radius R1 of the rim is struck from the fulcrum point B.

However, when viewing the top right-hand corner of Figure 6, it will be seen that the radii R5 and R6 are both struck from the fulcrum point C, and the radius R7 is struck from the fulcrum point D. The shoulder 112 therefore is formed with one width at the point 112A and a different width at 112B. Similarly the shoulder 124 has one width at 124A and another width at 124B. When these containers are stacked, in alternate sequence as in the previous embodiment, the wider shoulder 112B rests on the narrow shoulder 124A of the preceding container of the stack, and the wider shoulder 1243 rests on the narrower shoulder 112A as shown in Figure 7. It has been found that this arrangement allows for ready separation of the individual containers of a stack.

In order to accomplish the stacking of alternately arranged containers in order that the different abutments or shoulders will locate in their correct places, the containers may be moulded in alternate sequence and fed to a stacking machine in that sequence as described below.

Figure 4 illustrates an array of four containers each in accordance with the invention. The arrangement of the containers within the array becomes clear by reference to the abutment faces 22 and 24. Such an array is first moulded by conventional vacuum-forming techniques and then a trimming operation is employed to part the containers into individual units, which are then aligned so that each container has an opposite conformation of abutment faces 22 and 24 to that of the adjacent containers.

As illustrated diagrammatically in Figure 5, a series of such unitary containers is then fed, step by step, along a horizontal guideway 50 to a stacking machine 52. The stacking machine comprises a pair of vertical walls 54 each having a flexible retainer piece 56, and an elevator 58 which is actuated by a piston and cylinder unit 60. From the position shown in Figure 5, the elevator unit is retracted downwardly by collapsing of the piston cylinder unit 60, and the stack S of containers is retained in position between the walls 54 by the retainer pieces 56. The train of containers is next advanced by one step until the leading container is positioned beneath the stack S whereupon the piston cylinder unit 60 is actuated to raise the elevator 58. The leading container is entrained by the elevator and pushed on to the bottom of the existing stack over the retainer pieces 56, raising the stack somewhat off the retainers 56. The elevator is retracted, and the stack is once more rested on theretainers and the step-by-step sequence is repeated.

A similar sequence of operations may be enacted with respect to the container shown in the second embodiment and reference is made to Figure 8 which illustrates an array of four of those containers. Again it will be seen that the containers are arranged so that each container has an opposite conformation of adjacent shoulders 112 and 114 to that of the horizontally adjacent container. Afer parting of the containers they can be aligned and stacked as illustrated in Figure 5.

Claims

CLAN

1. A container of formed sheet plastics material comprising a container body and an out-turned rim, the upperside of said rim having a plurality of abutment faces and the underside of said rim having at least one bearing surface, the abutment faces and at least one bearing surface being positioned-so that when a like container is stacked thereon or thereunder the abutment faces of one container contact the at least one bearing surface of the other container to prevent complete nesting of the containers one within the other.

2. A container as claimed in claim 1 wherein the abutment faces are formed by lands extending inwardly from the uppermost face of the rim.

3. A container as claimed in claim 2 having four side walls wherein at least one land is provided on the rim of one of a first pair of opposite side walls.

4. A container as claimed in claim 3 wherein a land is also provided on the rim of each of the second pair of opposite side walls towards the ends of said side walls distant from that side wall of the first pair having lands.

5. A container as claimed in claim 1 wherein the abutment faces are formed by inwardly extending shoulders of varying width in the region of corners of the container rims, the shoulders projecting inwardly from the rim at both corners on one of a first pair of opposite side walls and inwardly from the rim of each of the other pair of opposite side walls at that corner distant from the said one of the first pair of side walls.

6. A container as claimed in claim 5 wherein the inwardly extending shoulders varies from a substantial width down to a comparatively narrow width as one moves from one shorter side wall to a longer side wall of the container, the inwardly extending shoulder of the opposite shorter side wall varying from a narrow width to a substantial width as one moves from said opposite shorter side wall to a longer side wall of the container.

7. A stack of like containers as claimed in any one of claims 1 to 6 wherein each member of the stack has a conformation which is reversed with respect to the adjacent container, the abutment faces of one container contacting the at least one bearing surface of the adjacent container positioned thereon.

8. A method of providing a stack of containers as claimed in claim 7 comprising forming sheet plastics material into a plurality of joined container forms, each container form having the container construction as claimed in any one of claims 1 to 6, but each container form having a conformation which is reversed with respect to the adjacent container forms, severing the container forms and feeding them, with alternate conformation, to a stacking mechanism.

9. A method as claimed in claim 8 wherein the stacking mechanism comprises a loading station for receiving each container in turn from a horizontal feed, and subsequently lifting said container onto the bottom of a stack of containers held by suitable suspension means.

10. A container of formed sheet portions material substantially as hereinbefore described with reference to any one of the accompanying drawings.