GB2104473A - Packaging container - Google Patents

Abstract

A container primarily for liquids and having an outwardly directed rim (15) to which a metal foil lid (18) is bonded after the container is filled, includes a rounded portion (17) and a dependent rim lip (16) on the rim (15). The lip (16) extends downwardly and towards the container wall (13) and is elastically deformable to engage the underside of the rim (15). The rounded portion (17) forms a rounded edge so that it is more convenient to drink directly from the container than with prior art containers having a sharp outer edge. <IMAGE>

Description

SPECIFICATION Packaging container This invention relates to packaging containers of thermoplastic synthetic material, in particular con tainers manufactured by heat forming a foil or plate of thermoplastic synthetic material, having a rim at the top in the form of a flange surrounding the opening area and extending substantially radially outwards, on which a flat lid, preferably a lid of metal foil, is to be sealed when the container has been filled. Packaging containers of this type are widely used as tub-shaped containers for milk products such as Yoghurt, but for beverages these known packaging containers have the disadvantage that the sealing rim surrounding the opening of the container has a fairly sharp edge so that it is not possible or at least not convenient to drink directly from the container.

German GM 6600652 discloses a packaging container of this type in which the sealing rim is slightly deformed at its free circumferential edge so that it does not coincide with the opening plane of the container but it can be elastically bent into this opening plane. The purpose of this design is to be able to compensate for unavoidable variations in thickness of the sealing rim by bending the rim elastically to varying degrees as required when the lid is sealed to it. In these known packaging contain ers, however, the sealing rim is just as sharp at the edge as in the other packaging containers of this type which have a virtually planar sealing rim.

It is therefore an object of the present invention substantially to improve packaging containers of the type mentioned above so that the opening rim of the container will have a smooth external circumference without an edge in order that the contents can conveniently be drunkstraightfrom the container but sealing of the lid to the container will not be made more difficult and will be achievable with conventional machinery in the same way as before.

To solve this problem according to the invention, the sealing rim of the packaging container is con tinuous at its external circumference with a rounded portion which extends into a lip rim which is folded downwards and towards the container wall and can be elastically bent to the underside of the sealing rim. This not only makes the container a convenient cup for drinking the contents without any risk of injury to the lips of the person drinking from it but also enables the container according to the invention to be closed in the same machinery for sealing a flat lid to containers as has hitherto been used for sealing conventional packaging containers.In this process, the lip rim which is elastically bent against the underside of the sealing rim while the container is being closed constitutes a spring element which is equally capable of absorbing variations in thickness of the sealing rim as the form of sealing rim proposed in German GM 6600652. The packaging container according to the invention thus not only ensures that a flat lid will be perfectly sealed to the container but also provides an improvement com pared with conventional packaging containers which have a substantially planar sealing rim. When the lid has been sealed to the container, the lip rim returns elastically to its original form and position.

The packaging container according to the invention is preferably circular or oval in cross section. If the container has a cross section which includes sharp corners, the lip rim may be omitted in the region of these corners since a userwould in any case not place his lips against such sharp corners for drinking out of the container.

In the packaging container according to the invention, the lip rim is preferably made thinner than the sealing rim so that it may be more easily bent elastically towards the underside of the sealing rim.

The thickness of the lip rim may for this purpose amount to ca. 20 to 80% of the thickness of the sealing rim.

The lip rim may have any form which enables itto be bent against the underside of the sealing rim during the sealing process; for example, it may taper downwards conically or it may taper downwards in the form of a curve with the concave side of the curvature facing the container wall. In order to ensure easy bending of the lip rim to the underside of the sealing rim, the lip rim may be made narrower than the sealing rim, but since the lip rim can also be bent elastically, at least if it is relatively thin, even a relatively wide lip rim can easily be placed against the circumferential wall of the container.

According to one particularly advantageous embodiment of this invention, the sealing rim is reduced in thickness in a radially outer annular region of transition to the lip rim. On the underside of the sealing rim, this annular region of transition may form a receiving surface for the lip rim which is pressed elastically against it.

Some examples will now be described with reference to the drawings, in which Figure 1 is a side view of a packaging container according to the invention, Figure 2 represents the region I of Figure 1, a) in section and b) while a flat lid is being sealed to it, Figure 3 is a similar representation to Figure 2 of a modified form of the area I of Figure 1, Figure 4 is a view similar to that of Figure 2 of a third form of the region I of Figure 1, and Figure 5 shows a fourth form of the region I of Figure 1 in a view corresponding to that of Figure 2.

The packaging container 10 shown in Figure 1 is made in one piece by deep drawing a thermoplastic synthetic material, for example polystyrene, or a laminate of several thermoplastic synthetic materials, and it is used for packaging yoghurt of a drinking consistency. The container 10 is circular in cross section. Starting from the bottom 11 of the container, the container wall 12 increases conically upwards and continues at its top end into a stacking and stabilizing rim 13 which is conical in the opposite direction. This stacking and stabilizing rim 13 ends at the top in a sealing rim 15 situated in the opening plane 14 of the packaging container 10. At its external circumference, this sealing rim 15 is continuous with a lip rim 16 which extends downwards from the sealing rim 15 and inwards with respect to the axis of the container.The transition from the sealing rim 15 to the lip rim 16 is formed by an outwardly rounded portion 17 for convenience of drinking.

In the example of Figure 2, the lip rim 16 extends substantially conically downwards and inwards from the external circumference of the sealing rim 15 to form an angle a of approximately 40 between the sealing rim 15 and the lip rim 16. The thickness of the lip rim 16 in this example amounts to approximately 50% of the thickness of the sealing rim 15.

This means that with a sealing rim having the conventional thickness of approximately 1.0 mm, the thickness of the lip rim is approximately 0.5 mm.

As shown in part b) of Figure 2, the filled packaging container 10 is closed by sealing a flat lid 18, for example of metal foil or a laminate of metal foils and layers of thermoplastic synthetic material, to the sealing rim 15. For this purpose, the filled packaging container 10 is placed in a sealing support 20 with a holder 21 positioning the sealing rim 15.

The lip rim 16 comes to lie on the supporting surface of the sealing support 20. When the hot sealing tool 22 then exerts pressure from above onto the edge of the lid 18 and from there onto the sealing rim 15, the lip rim 16 moves elastically towards the underside of the sealing rim 15. The resulting tension in the lip rim 15 produces a counterforce against the pressure of the sealing tool 22 sufficient to ensure that the sealing rim 15 and lid 18 will press against the sealing tool 22 from below with sufficient force to produce a seal even in those circumferential regions in which the sealing rim happens to be somewhat thinner.

When the lid 18 has been sealed to the container, that is to say when the sealed container 10 is removed from the sealing support 20, the lip rim 16 substantially returns to the position shown in part a) of Figure 2 but even if the lip rim 16 should undergo permanent deformation during sealing of the container 10, the rounded portion 17 shown in part b) of Figure 2 will in any case remain on the external circumference of the edge of the container for the convenience of drinking.

In the example of Figure 3, the lip rim 16a extends further downwards than in the example of Figure 2 and is slightly curved with the concave side of the curvature facing the container wall or the stacking rim 13, in other words the convex side of the curvature faces outwards. In this example, the thickness of the lip rim 16a amounts to approximately 40% of the thickness of the sealing rim 15 and diminishes from its zone of connection to the sealing rim 15 or rounded portion 17 to its free edge.

As shown in part b) of Figure 3, the pressure exerted on the lid 18 and sealing rim 15 by the sealing tool 22 is sufficient to push the curvature of the lip rim 16 elastically inwards until the lip rim 16a makes contact at least in part with the underside of the sealing rim 15. The curvature of the lip rim 16a increases the counter force which is produced when the underside of the sealing rim 15 is elastically bent, with the resultthatthe sealing rim 15 and lid 18 are firmly pressed against the underside of the sealing tool 22 over their whole circumference even if the sealing rim 15 is reduced in thickness in parts of its circumference.

Whereas in the examples of Figures 2 and 3 the width of the lip rim 16 or 1 6a is less than the width of the sealing rim 15 so that the free circumferential edge of the lip rim 16 or 16a remains at some distance from the container wall or stacking ring 13 even when the sealing rim is pushed upwards to the underside of the sealing rim, in the example of Figure 4 the lip rim 1 6b is wider than the sealing rim 15. The lip rim 16b is substantially conical in this example and tapers downwards. This form is to be chosen in those cases, for example, in which the axial height h covered by the lip rim is required to be particularly great. The thickness of the lip rim 1 6b in this example amounts to approximately 40% of the thickness of the sealing rim 15.Furthermore, the thickness of the rim 1 6b decreases from its point of connection with the sealing rim 15, i.e. from the rounded portion 17, to the free edge of the lip rim 16b.

As may be seen from part b of Figure 4, the free edge of the lip rim bears against the external surface of the stacking rim 13 when the lip rim 16b is elastically bent towards the underside of the sealing rim 15 bythe pressure exerted on the lid 18 and sealing rim 15 by the sealing tool 22. As in the example of Figure 3, the lip rim 16b then again undergoes elastic deformation within itself whereby the counterforce in the lip rim is increased and the uniform quality all round the circumference is improved even in the event of irregularities in the thickness of the sealing rim 15.

In the example of Figure 5, a relatively narrow, thin lip rim 16c is formed on the outer circumference of the sealing rim 15c. Furthermore, the sealing rim 15c has an annular region oftransition 23 in its outer part which, when the upper surface of the sealing rim 15c is flat, forms a receiving surface 24 extending round the underside of the sealing rim 15cto receive the lip rim. As shown in part b of Figure 5, the container 10 in the embodiment of Figure 5 may also be sealed in those conventional sealing apparatus for application of a flat lid 18 in which the sealing support 20c has a supporting surface which is completely planar right up to the holder 21. In such a case, the lip rim 16c is completely pushed into the receiving surface 24 of the lip rim when the container 10 is being sealed.If, on the other hand, a sealing support 20 as shown in the examples of Figures 2 to 4 is used, which has a depression between the effective supporting surface and the holder 21, then the lip rim 16 can move with little or no deformation into this depression of the sealing support 20 (see broken lines in part b of Figure 5). The packaging containers 10 may be made of any thermoplastic synthetic material conventionally used for this purpose. Instead of having a circular cross section. If the packaging containers have a polygonal cross section, the lip rim 16, 16a, 1 6b or 1 6c would only extend to the vicinity of each corner of the cross section and would be omitted in the region of the corner itself, thereby avoiding any difficulties in bending the lip rim against the underside of the sealing rim at the corners. Moreover, the lip rim would not be required in these corner regions of the cross section since the user would not normally drink from the corners of the container.

Claims (12)

1. Packaging container of thermoplastic synthetic material, in particular a container manufactured by heat forming a foil or plate of thermoplastic synthetic material, having a rim at the top in the form of a flange surrounding the opening area of the container and extending substantially radially outwards, on which rim a flat lid, preferably of metal foil is to be sealed when the container has been filled, characterised in that the sealing rim (15) is continuous at its external circumference, by way of a rounded portion (17), with a lip rim (16) which is folded downwards and towards the container wall (12, 13) and can be elastically bent to reach the underside of the sealing rim (15).

2. Packaging container according to Claim 1, characterised in that the lip rim (16) is thinner than the sealing rim (15).

3. Packaging container according to Claim 2, characterised in that the thickness of the lip rim (16) is approximately from 40% to 80% of the thickness of the sealing rim )15).

4. Packaging container according to the Claims 1 to 3, characterised in that the lip rim (16) tapers conically downwards.

5. Packaging container according to one of the Claims 1 to 3, characterised in that the lip rim (16) tapers downwards in a curve, with the concave side of the curvature facing the container wall (12, 13).

6. Packaging container according to one of the Claims 1 to 5, characterised in that the lip rim (16) is narrower than the sealing rim (15).

7. Packaging container according to one of the Claims 1 to 6, characterised in that at the circumference of the lid, the sealing rim (15c) is reduced in thickness in an annular region of transition (23) to the lip rim (16c).

8. Packaging container according to Claim 7, characterised in that on the underside of the sealing rim (15c), the annular transition region (23) forms a receiving surface (24) for the lip rim (16c) which is pressed elastically against it.

9. Packaging container according to one of the Claims 1 to 8, characterised in that when the cross section of the container is round, preferably circular, the lip rim (16) extends continuously around the whole circumference of the sealing rim (15).

10. Packaging container according to one of the Claims 1 to 8, characterised in that when the cross section of the container is angular, the lip rim (16) extends to the region of each corner on each side of the container to be cut away at the corner itself.

11. A container of synthetic thermoplastics material having a container wall with an upper sealing rim in the form of a flange surrounding an opening of the container and extending outwardly from the opening, on which rim a substantially flat lid is to be sealed when the container has been filled, wherein the rim (15) is continuous at its external boundary, the rim including a rounded portion (17), and a lip (16) which is folded downwardly and towards the container wall (12, 13) and can be elastically bent to reach the underside of the rim (15).

12. Athermoplastics container constructed and arranged substantially as herein described and shown in the drawings.