EP0459017B1 - Procedure for the manufacture of a closure made of paper - Google Patents

Description

The invention relates to a method for producing a cardboard cover.

Such closure covers have become known on the one hand as so-called overlapping covers, on the other hand as so-called insert covers, and the invention is directed to both types of covers.

Cans for holding foods or the like which are made from cardboard are known to a large extent today. Although these containers are covered with a wafer-thin layer of plastic, they decompose in the garbage and therefore do not represent a long-term pollution of the environment. H. are trained to be environmentally friendly.

The lids of such containers are still completely made of plastic to this day, since it was not possible to produce dimensionally stable lids from cardboard. It must be noted here that the lids are placed on the can only after a long time after their manufacture, namely after the can in a filling plant or the like Good to be picked up is filled. In the meantime, deformations cannot be excluded. In addition, environmental influences such as temperature and moisture act on the lid and contribute to the deformation of the lid.

These lids are therefore without question a burden on the environment and are a disposal problem, while a closure lid made of cardboard - that is, the same material as the can body - would not have to be disposed of separately from the can.

From DE-PS-251 424 a capsule closure made of cardboard for vessels with a spherically reinforced neck and retraction under the reinforcement has become known, this capsule closure has a slightly outwardly bent, ring-like edge at its lower end. As a result, the lower part of the capsule closure is made more resistant and provided with material which is sufficient to withstand the tension which arises when the capsule is applied to the bottle and which is able to compensate for the changes in shape of the lower part of the capsule during this application . Such a bend, as described in the cited reference, has not become known in practice and such a bend is also not able to remain stable for a long time, since the cardboard material has a certain "memory", and that to the outside bent edge of the capsule closure must strive to bend back into the original position. This bending back under the influence of the "memory" is reinforced by moisture and temperature differences.

In US-A-20 14 901, on which the preamble of claim 1 is based, a container with a lid is described. The container and lid are made of cardboard and should be prefabricated so that they can be assembled and assembled at the point of use. The lid consists of a round blank, which is cut at its edge, so that a plurality of individual tongues are formed, which are then bent over a stabilizing ring. The individual tabs are preferably glued to the outside and inside of the stabilizing ring.

The manufacture of such a cover is complex and requires precision tools in order to produce the necessary incisions in the desired size and position.

In US-A-22 44 940 an assemblable container is also described. Here, too, the lid or the bottom can be formed by a round blank, which is provided with incisions on its circumference, so that flaps are also formed here, which lie against the outside of the wall of the can and are glued here.

Finally, a container closure is known from US-A-23 83 760 , which consists of cardboard, the lid being punched in a certain shape. It is not explained here how this form of cover can be achieved and a circumferential strip is attached to the peripheral, downward-facing edge of the cover, which is obviously intended to preserve the shape of the cover. According to this view, this lid is not dimensionally stable and is therefore not suitable for securely closing food-absorbing foods Suitable for container cans.

The invention has for its object to provide a method for manufacturing a lid for cans or can-like containers, which can be made of cardboard and still has the required strength, in particular the necessary stability.

This object on which the invention is based is achieved by the teaching of the main claim.

Exemplary embodiments are explained in the subclaims.

In other words, it is proposed that the circumferential, upward or downward flange of a lid - depending on whether it is an overlapping lid or an insert lid - is formed from the grooved edge of a round blank and then provided with a stabilizing ring, which is tight on the outside or inside of the flange. Since the lids as well as the cans are provided with a wafer-thin plastic covering, it is now possible to fuse the thin plastic layers that come into contact with each other by applying heat to the area of the circumferential stabilizing edge or flange and by applying appropriate pressure, so that the stabilizing edge is firmly attached to the normal circumferential flange. Surprisingly, it was found that this simple measure enables the lid to have a high level of stability.

While it is assumed in the foregoing that a wafer-thin plastic covering is present on the can and lid, it is of course also possible if this wafer-thin plastic covering does not it is intended to replace this with a corresponding adhesive layer, so that the same advantages are then achieved by sticking the stabilizing edge and flange together.

Since the amount of gluing or welding between the flange and the stabilizing edge or stabilizing ring can be chosen freely, it is even possible to create a closure in which the inner part of the bent flange which then protrudes somewhat, i. H. of the stabilizing ring, forms an abutment, which on the one hand stores an overlapping lid more securely on a can, on the other hand even gives the possibility that the lid cannot be separated from the container without damage, so that unauthorized testing and inspection of the container contents is no longer possible.

Fig. 1

schaubildlich eine Dose mit einem Übergreifdeckel, in

Fig. 2

eine Ronde zur Herstellung eines Deckels, in

Fig. 3 und 4

eine erste Ausführungsform von zwei verschiedenen Arbeitsstadien zur Herstellung eines Deckels, in den

Fig. 5 und 6

unterschiedlich hoch miteinander verklebte oder versiegelte Stabilisierungsränder, in den

Fig. 7 und 8

abgewandelte Ausführungsformen einer Deckelkonstruktion in verschiedenen Arbeitsstadien, in den

Fig. 9 und 10

abgeänderte Ausführungsformen in verschiedenen Arbeitsstadien, in den

Fig. 11 und 12

einen Einsatzdeckel mit Stabilisierungsrand und in

Fig. 13

eine Dose mit aufgesetztem Deckel.

Embodiments of the invention are explained below with reference to the drawings. The drawings show in

Fig. 1

graphically a box with an overlap, in

Fig. 2

a round blank for the production of a cover, in

3 and 4

a first embodiment of two different working stages for the production of a lid, in the

5 and 6

stabilizing edges glued or sealed to different heights, in the

7 and 8

modified embodiments of a lid construction in different working stages, in the

9 and 10

modified embodiments in different working stages, in the

11 and 12

an insert lid with stabilizing edge and in

Fig. 13

a can with a lid on.

In Fig. 1 a box 1 is drawn, which has an overlap 2, the overlap 2 is equipped in a manner known per se with a downward rotating flange 3. The overlap 2 engages with its downward flange 3 over the outside of the upper edge of the box 1. The downward flange 3 carries a tear tab 22, so that in certain embodiments of the overlap 2 a loosening of the overlap by actuating the tear tab and thus Separation of the flange 3 in two parts is possible.

For the manufacture of the lids to be described below, for example lid 2, a cardboard blank 20 is assumed (FIG. 2), which is equipped, at least in its edge region, with grooves 21 which prevent the flange to be bent later from being reset.

In order to give such a cardboard cover 2, which is therefore usually not dimensionally stable, a shape stability, the circumferential flange 3a of a cover 2a is bent inwards and forms a stabilizing ring 4a in this way. This stabilizing ring 4a is pressed under the influence of heat on the inside of the downward flange 3a and by fusing the thin plastic layer fixed so that the lid shown in Fig. 4 is achieved. Instead of the action of heat and the welding of the plastic layers coming into contact with one another, an adhesive bond can also be used so that the adhesive layer acts instead of the plastic layer.

The illustration in FIGS. 5 and 6 makes it clear that it is possible to extend the flange 4a to a greater or lesser extent, ie. H. high enough to weld on the inside of the flange 3a, so that the upper part of the stabilizing ring 4a or 4b protrudes more or less inwards. From the illustration in Fig. 13 it can be seen that a securing of the lid 2a is achieved, which makes it possible either to clamp the lid 2a particularly tightly on the can 1a or to form it as a security lid, so that it even provides security against unwanted opening there.

7 and 8, the downward circumferential flange 3c is bent inwards as before. A reinforcing ring 5 is inserted into the U-shaped space thus created. This reinforcing ring 5 is then firmly connected to the circumferential flange 3c by the action of heat, specifically also to the inside of the bent edge of this flange 3c. This achieves the stabilizing ring 3c of the cover 2c, which - with reference to the illustration in FIGS. 5 and 6 - can be welded or glued to a greater or lesser extent in the same way.

In the embodiment according to FIGS. 9 and 10 an additional stabilizing ring 4b is provided, which is J-shaped in the illustrated embodiment. The small leg lies on the inside of the circumferential flange 3b of an overlapping cover 2b directed downward and the large flange of the stabilizing ring 4b lies on the outside of the flange 3b. Here, too. B. by the heat of the flange 3b firmly connected to the stabilizing ring 4b.

In the embodiment shown in FIGS. 11 and 12, 11 denotes a closure cover, which essentially consists of a bottom 12 and an upright edge 3. Fig. 11 shows that the free edge of the edge 13 are bent outwards, i. H. In the upper region of the edge 13, a U-shaped flange 15 is created. If this U-shaped flange 15 is now exposed to pressure from the outside inwards, the U-shaped flange 15 bears against the outside of the edge 13 and - since the starting material has been provided with a fine plastic coating - the heat can now be applied Flange 15 are glued to the outside of the edge and then forms a stabilization ring 14 which can be seen in FIG. 12. This stabilization ring 14 has the effect that the bent edge 13 can no longer be reset, i. H. a closure cap 11 is created which is dimensionally stable and which can also be placed on the filled can for a long time after its manufacture in the filling factory.

The stabilizing ring 14 lies on the upper edge of the can in the case of the closure lid 11 and thus represents a stop. At the same time, this stabilizing ring 14 also serves as a handle, so that the cover 11 can be easily loosened.

In the drawing, a round cover 11 is shown, but it goes without saying that this cover can also be polygonal.

In FIG. 13, a can 1a with a cover 2a is shown to clarify the application, this cover 2a being formed by the protruding stabilizing flange 4a as a safety cover, which is provided with a tear-open tab 22.

Claims (5)

1. A method for producing a sealing cover, which is constructed as an overlapping cover or an insert cover,

   a) a circle (20) being produced from cardboard,

   b) a dish-shaped cover (2, 2a, 2b, 2c, 11) thereafter being formed from the circle (20) and

   c) an encircling stabilising ring (4a, 4b, 4c, 14) subsequently being welded or adhered at least to the area of the encircling flange (3, 3a, 3b, 3c, 13) of the cover rim opposite the stabilising ring,

   characterized in that before step b)
      a1) channels (21) are created in the rim area of the circle (20) by pressing in a corresponding tool.
2. A method according to claim 1 characterized in that the lower rim edge of the encircling flange (3a) is bent inwards and is fastened to the inside of the encircling flange (3a) by adhesion and/or welding and thus forms the stabilising ring (4a).
3. A method according to claim 1, characterized in that the lower rim edge of the encircling flange (3c) is bent inwards, a reinforcing ring (5) is inserted into the space in the U formed in this way and then the bent rim and the reinforcing ring (5) are fastened by adhesion and/or welding to the inside of the encircling flange (3c) and in this way form the stabilising ring (4c).
4. A method according to claim 1, characterized in that a J- or U-shaped stabilising ring (4b) is inserted, which is fastened to the inside and outside of the encircling flange (3b) by adhesion and/or welding.
5. A method according to claim 1, characterized in that the encircling free edge of the rim (13) of a cover (11) is bent outwards and fastened to the outside of the rim (13) of the cover by adhesion or welding.

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