CA2239600C

CA2239600C - Tin for foodstuffs

Info

Publication number: CA2239600C
Application number: CA002239600A
Authority: CA
Inventors: Wolfgang Peter; Hans Hartung; Horst Becker
Original assignee: Impress Metal Packaging GmbH and Co OHG
Current assignee: Trivium Packaging Germany GmbH
Priority date: 1995-12-04
Filing date: 1996-12-04
Publication date: 2006-09-05
Anticipated expiration: 2016-12-04
Also published as: CA2239600A1

Abstract

The invention concerns a tin for foodstuffs, the tin comprising a base and a peripheral wall which projects from the base and surrounds an inner space. T he upper edge of the wall delimits all around an opening in the inner space, the inne r space widening conically upwards and the wall, which surrounds this inner space, merging at the bottom into the base at a rounded portion. The merging region is designe d such that a peripheral annular bearing line is produced but, on the interior, the base is first further extended upwards and then a bearing surface between 1.5 and 10 mm wi de is produced by a downwardly projecting peripheral annular bead.

Description

The invention relates to a can body with a base and a side wall which projects from the base and surrounds an interior.
Can bodies are known in many forms. Very different foods are packaged in them and requirements made of them with regard to aesthetic appearance, durability, stability and stackability vary.
A can made from sheet metal is known for example from DE-GM 19 98 472 which is circular in cross-section with side walls widening upwards and which has a base which at the bottom rests on the ground by means of an annular positioning part, whilst the central region of the base is curved upwards, so that it does not touch the ground when the can is set down. The side walls are curved.
The stability of the can body is increased due to the fact that the base is not planar, since completely planar bases could distort and in the case of irregularities due to manufacture also lead to the can body not standing definitely on the ground but for example only resting unstably locally on a more or less randomly lowest point of the base 2 0 and the whole can therefore tends to wobble.
The positioning part which is the round edge which runs round, on which the can body rests on the ground, has a finite width in this known embodiment; it merges with a slight bend into the side wall.
It would be desirable if the can bodies were even more stable against external demands. It is therefore the object of the invention to propose such a can body.

3 0 The invention achieves this object by a can body with a base and a side wall running round it which projects from the base and surrounds an interior and which with its upper edge delimits an opening of the interior all round, wherein the interior widens conically upwards and the side wall surrounding it merges at the bottom into the base with a rounding in such a way that an annular supporting line running round the base is produced, but inwardly the base is initially further extended upwards but then due to an annular bead running round which projects downwards a supporting surface with a width of 1.5 mm, particularly 2 to 10 mm is produced.
Such a can body has a considerable number of advantages. Externally its supporting surface when it is set down is provided by an annular line. Further inwards is located an additional supporting surface with a defined width which extends approximately parallel to the supporting line, that is to say is also annular. The combination of these two supporting zones is shown in tests to increase stability particularly well. In the figurative sense a three-point bearing is produced, namely by an areal and a linear support, that is to say an expanse and a point viewed in section.
This supporting surface is particularly stable not only against forces from the side, from below or also from the can body itself, it is also immune to manufacturing tolerances and withstands any expansion and bending forces originating from the interior of the can body. These forces may be produced not only by the filling of the can but also when a series of empty can bodies are placed one inside the other_ This is in fact also possible due to the shape which is produced overall. The side walls which widen conically upwards make it possible for empty cans to be placed one inside the other so as to save space after manufacture and before filling in food processing plant_ Naturally this leads to forces which the empty can bodies exert on one another. However, it is precisely these forces which are absorbed by this special construction of the base.
It is especially preferred for this if the upper edge around the opening has a rim profile with three alternating curvatures which form a shoulder or a stepped rim.

The slightly conically shaped containers which are stacked on one another are each supported with the stepped rim, so that the conical side walls moreover come into little or no contact with one another and jamming is impossible.
As a result stacking and unsticking of several containers is made significantly easier, and at the same time the overall stability and definability of the stacking properties are increased especially in conjunction with the combination of supporting line and supporting surface in the base.
It is particularly preferred if the can body is made from metal. In theory it is also conceivable to extend these shapes to containers made from plastics material, but in the case of metal bodies the features according to the invention have proved particularly advantageous in tests_ It is also preferred if the rounding has a radius of curvature of more than 4 mm. The rounding at which the side walls merge into the base is 2 0 decisive for the extent of the line shape of the supporting line, also for the behaviour of the can body when it is brought out of its rest position, for example in filled form on the shelf of a supermarket_ Due to the relatively great convexity with a large radius of curvature, the self-adjustment of the can body in filled form can be accomplished 2 5 particularly favourably. Also the optically and aesthetically pleasing appearance is of greater advantage; a spherical shape like a soup pot is produced, which has a particularly attractive effect.
It is preferred if the opening is circular. Naturally, however, it is 3 0 also possible to provide oval, approximately rectangular or even quite differently shaped openings, of which the shape then naturally also takes effect as far as the base region.
The distance between the supporting line and the supporting surface should advantageously be between 7 and 30 mm. With these dimensions . ' ,.

the uniform distribution of the forces acting on the base is applied particularly well.
The diameter of the annular supporting surface should be approximately 20 to 80 mm. Also this enhances the effect according to the invention.
The stackability and unstackability in particular of non-round cans is even further improved if the side wall is provided with corrugations.
The side wall which runs round the can is made so rigid by these corrugations that springing in of the side wall does not occur. As a result the can body retains its shape even under loading. Such loading can occur in particular during filling of the can container, quite particularly when the lid is flanged on after filling. Stability of shape of the body is important especially during this part of the process in order to ensure superimposition of the material of the lid and container on one another so as to facilitate the flanging operation in which the materials of the can body and the appertaining lid are folded into one another.
The stackability and unstackability is also important since while the can bodies are still empty and without lids they must be capable of being placed one inside the other to save as much space as possible, so that for instance when the uppermost can body is lifted off the next one does not come with it. This is also assisted by the corrugations.
2 5 This applies quite particularly when the corrugations extend substantially vertically.
This is further assisted if the corrugations extend downwards from the region of the shoulder or one of the shoulders over a substantial part of the side wall.
In this way the corrugations have the task not only of stiffening the side wall but also of guiding the various can bodies in one another, especially during the stacking or unstacking operation. Due to the . -termination of the corrugations towards the top, easy uniform removal is possible here.
An embodiment of the invention is described in greater detail below with reference to the drawings, in which:
Figure 1 shows a cross-section through a can body according to the invention;
Figure 2 shows a perspective top view of the can body of Figure 1;
Figure 3 shows the can body of Figure 2, partially cut away and with the lid shown in a similar form but not yet put on firmly;
Figure 4 shows another embodiment of acan body viewed obliquely from above;
Figure 5 shows the embodiment of Figure 4 obliquely from the side with two alternative possibilities for design of the lid; and Figure 6 shows a third embodiment of a can body according to the invention.
A can body has a base 10. A side wall 20 projects upwards from this base 10. The side wall 20 surrounds an interior 30. The material, particularly food, which is to be transported with the can and stored therein is introduced into this interior 30.
The side wall 20 surrounds with its upper edge an opening 31 of the interior 30 all the way round; this opening can (indicated in Figures 3 and 5) be closed by a lid 40 and as a rule this is done after the filling has been put in.
The interior 30 widens conically upwards. This means that the side wall 20 which runs round and projects from the base diverges upwards.

At the bottom the side wall 20 merges into the base 10 by a rounding 21. This takes place in such a way that the rounding 21 forms an annular supporting line 11 running round the base. The rounding itself has a radius of curvature of e.g. 4.5 mm or 8 mm in the case of can bodies of typical sizes.
Seen in cross-section from the outside inwards this supporting line 11 appears in Figure 1 as a point. However, as seen further towards the centre of the can body base 10, inwards from the supporting line 11 the base 10 first of all goes further upwards, that is to say it leaves the support plane_ After this relatively short arching 32, of which the bend amounts to approximately 7 to 30 mm and which is directed towards the interior 30, an annular bead 15 which runs all round then again projects downwards_ However, this bead 15 does not form a supporting line but a supporting surface 16 with a width of 1.5 to 10 mm. In the section in Figure 1 this supporting surface appears as an expanse with a length of 1.5 to 10 mm.
From this bead, further in the direction of the centre of the can body base 10, the base then again leaves the support plane and returns somewhat into the direction of the interior 30.
'this is repeated symmetrically on the other side of Figure 1; in the case of a can body having a circular opening 31 overall this section is approximately the same at any location on the can.
In Figure 2 in the perspective view the bead 15 can also be seen obliquely inwards from above. from the interior 30 it appears as a projection downwards without any shading at all due to its planar flat construction. The central region of the base 10, which in contrast to the bead 15 does not however rest on the ground when the can body is set down, is also shown planar and without shading.

The opening 31 of the interior 30 is as stated surrounded by the upper edge of the side wall 20. This is provided as a rim profile with three curves bent alternately inwards and outwards which form a shoulder 22 or a stepped rim. Two containers placed one on the other project into one another with their conically shaped side walls 20, in which case the side walls would extend parallel to one another and slightly spaced from one another. The shoulders 22 then rest on one another. This stacking behaviour is assisted by the bead 15 which favours the stability and thus also the centricity of the container.
Figure 3 shows the embodiment of Figure 2 with less of an inclination, and moreover the right-hand quarter of the can body facing the observer is cut away. Thus a sectional edge can be seen which corresponds to the one in the right-hand half of Figure 1, but the roundings and proportions produced in three dimensions are also shown at the same time.
The lid (not cut away) is shown spaced above the opening 31.
Figures 4 and 5 show another embodiment of a can body. Here the opening 31 is not circular but an extended rectangle with rounded corners, that is to say approximately long oval. As a result the annular bead 15 and the annular supporting line 11 each also have straight stretches.
Here too the side wall or side walls 20 are constructed so that they slightly diverge conically upwards.
For the purpose of comparison two different forms of possible lids 40 are shown here one above one the other over the opening 31.
A third embodiment of the invention is shown in Figure 6. This embodiment is also a convex can and has a non-round, slightly conical shape similar to the embodiment of Figures 4 and 5, with the addition here of a stepped rim 22 with side corrugations 25, For clarity some _g-reference numerals have been omitted here, but these correspond to those of the other Figures.
The container or can body has a relatively large radius at the transition from the side wall to the base 10.
This is a packaging alternative of pleasing shape, especially with an easy-opening lid, for example with a pull-off closure_ It has a stepped rim 22 for high stability and good stackability and unstackability of one and several further can bodies in the interior 30. Rigidity at the base 10 is achieved by a supporting surface with stabilising bead.
In this case the side wall 20 which runs all round is so rigid that springing in of the side wall 20 does not occur. As a result the body retains its shape and facilitates good superimposition of material between lid 40 and container, so that the lid 40 can be securely flanged on.
The body to be stacked can rest on a first shoulder of the lower can body, which shoulder runs all round or is locally interrupted and is located in the region of the opening 31_ In this case a spacing is formed between the flanged rims of both bodies which facilitates the destacking of the containers from one another. The rigidity of the side walls 20 is increased by a second shoulder which first of all extends upwards in the shape of an arc of a circle and then inwards in the shape of an arc of a circle over the first shoulder, particularly in the region of the uncurved side walls or only on the long sides, in conjunction with side corrugations 25 which extend substantially vertically and are constructed with a round, oval, triangular, trapezoid or polygonal contour. Figure 6 shows only one version here with a shoulder and simply constructed corrugations 25.
In this case the corrugations 25 terminate upwards in the region of the side rim 22, that is to say at the height of the second shoulder, _g_ between the first and second shoulder or in the first shoulder. The guiding of the side corrugations 25 in conjunction with the shoulder brings about an extremely good wall rigidity, so that the force of the flanging tools transmitted to the side wall 20 during flanging does not lead to deformation of the wall and on the other hand, in the case of can bodies which are stacked one above the other and are filled and closed, the side walls have the necessary rigidity against bending in or out even during filling.

Claims

1. A can body comprising:
a base; and a side wall running round the base, the side wall projecting from the base, defining an interior and having an upper edge which delimits an opening in the can body, wherein the interior widens comically upwards wherein the side wall merges into the base with a rounding in such a way that an annular supporting line running around the base is produced, wherein, inwardly of the supporting line, the base initially further extends upwardly, and wherein the base has annular bead which projects downwardly to produce, inwardly of the supporting line, a supporting surface with a width of 1.5 to 10mm, wherein the base is sufficiently stable to permit the can body to be used to produce a can that can withstand expansion forces originating from the interior of the can body during processing.

2. A can body as claimed in claim 1, characterised in that it is made from metal.

3. A can body as claimed in claim 1 or 2, wherein the rounding has a radius of curvature of 4 to 8 mm.

4. A can body as claimed in one of claims 1-3, characterised in that the opening is circular.

5. A can body as claimed in one of claims 1-3, characterised in that the opening is non-round, long oval, elliptical or quadrangular.

6. A can body as claimed in one of claims 1-5, characterised in that the distance between the supporting line and the supporting surface is between 7 and 30 mm.

7. A can body as claimed in one of claims 1-6, characterised in that the diameter of the annular supporting surface is between 20 and 80 mm.

8. A can body as claimed in one of claims 1-7, characterised in that the upper edge around the opening has a rim profile with three or more alternating curvatures which form one or more shoulders or a stepped rim.

9. A can body as claimed in one of claims 1-8, characterised in that the side wall is provided with corrugations.

10. A can body as claimed in claim 9, characterised in that the corrugations extend substantially vertically.

11. A can body as claimed in claim 9 or claim 10, characterised in that the corrugations extend downwardly from the region of the shoulder or one of the shoulders over a substantial part of the side wall.