EP3837063B1 - Can packaging, and apparatus and method for the production of its blank - Google Patents

Description

Technical area

The invention relates to a can packaging, a can packaging blank and a device and a method for their production.

State of the art

Can packaging is often formed from blanks that have been produced using an extrusion process. An extrusion process is a forming process in which a workpiece is formed using compressive stress. The direction of flow of the material relative to the direction of punch movement provides the basis for the distinction between forward extrusion (material flow and direction of punch movement are the same), backward extrusion (material flow and direction of punch movement are opposite) and transverse extrusion (material flow transverse to the direction of punch movement).

The production of a thin-walled metal tube by backward extrusion is in the DE 29 32 016 C2 described. The DE 197 08 826 A1 describes a can made of thin-walled sheet metal, consisting of a bottom part made in one piece by extrusion, an adjoining, tubular middle part and a lid located on the side of the middle part opposite the bottom part and connected to the middle part by flanging. The base part has ribs, beads or the like, which are introduced into the base part in the course of the extrusion process when producing the base part with a central part. The DE 41 33 340 A1 describes the production of a capacitor cup housing with alternating thinner and thicker wall thicknesses by backward extrusion, with the thinner wall thicknesses forming triangular weakenings as predetermined breaking areas. The preamble of patent claim 1 is based on this publication. US 6,126,034 A discloses the production of a can packaging blank with alternately thinner and thicker wall thicknesses by ironing the wall of a can blank made of sheet metal.

In connection with can packaging, there is often a desire to make them not only visually but also haptically characteristic and distinguishable from one another. This is usually achieved by deforming or shaping the can packaging blank or the can packaging. However, the problem arises that every deformation of the outer surface is accompanied by a corresponding deformation of the inner surface and thus of the can container interior.

A circumferential waist of the can, for example, means that the interior of the can initially tapers and then widens again towards the bottom of the can. As a result, on the one hand, there is a reduced interior space available compared to the unfitted cylindrical can. On the other hand, problems arise when filling the can packaging, which can only be done with lower pressures and therefore more time. Problems also arise when emptying the can packaging, as any shape that deviates from a smooth, continuous inner surface promotes the retention of content residues and makes it more likely.

There is therefore still a need for can packaging that has a tactilely distinguishable outer surface and at the same time can be filled easily and quickly and emptied with as little residue as possible.

Presentation of the invention

The present invention is based on the object of providing a can packaging which has a haptically distinguishable outer surface and at the same time can be filled easily and quickly and emptied with as little residue as possible. This object is achieved according to the invention by the device for producing a can packaging blank according to independent claim 1, by the method for producing a can packaging blank according to independent claim 9, and by the can packaging according to independent claim 12. Further advantageous aspects, details and refinements of the invention result from the dependent claims, the description and the drawings.

The present invention provides an apparatus for producing a can packaging blank by reverse extrusion. The device has a die and a press punch, the die having a die base and a die wall with a die wall height. In its area adjacent to the die base, the die wall has at least one projection with a predetermined width, a predetermined height, a predetermined depth and a predetermined cross section, the height of the projection being a maximum of 95% of the die wall height.

Due to the projection provided according to the invention in the area of the die wall adjacent to the die base, a haptically perceptible design can be achieved the outside of the wall of a can packaging blank or the can packaging made from this blank, without there being any change to the inner surface of the wall of the can packaging blank or the can packaging. The structuring of the outer surface, i.e. the outside of the wall of the can packaging blank, does not take place by subsequent deformation, as is known from the prior art, but rather during the manufacturing process when the can packaging is created. During all subsequent deformation steps, the wall of the can packaging is dented, notched, bulged or otherwise changed while maintaining the previously formed wall thickness. What all deformation steps have in common is the fact that the deformation visible on the outside becomes visible as a negative on the inside. If the can wall is dented, the corresponding area appears as a depression on the outer surface and as an elevation on the inner surface. Conversely, the same applies: If the can wall is dented, an elevation appears on the outside, which is matched by a depression on the inside of the wall of the can packaging.

In contrast, the structuring of the outside of the wall caused by the device according to the invention for producing a can packaging blank takes place directly during the manufacturing process by backward extrusion by varying the wall thickness of the can packaging blank. The projection provided in the area of the die wall adjacent to the die base causes the backward-flowing metal in the area of the projection to create a recess shaped in accordance with the shape of the projection in the wall of the can packaging blank that is being formed. The simplest example is a point-shaped tip with a height of 0.1 mm as a projection on the die wall. This tip leaves a groove 0.1 mm deep in the metal flowing past and forming the wall. However, this depression that is visible on the outside has no counterpart in the form of an increase on the inside of the can wall. This remains smooth and continuous like can packaging without any structuring on the outside.

Based on this basic idea of a projection in the form of a tip, there are almost any number of possible variations. First, the number of projections and their distribution over the circumference of the die wall can be varied. The outside of the wall can be designed, for example, in the form of two grooves arranged closely next to one another, but can also be designed as a large number of grooves distributed in relief over the circumference of the can packaging.

The shape of the projection as well as its width, height, depth and cross section can also be varied. In this way, relief-like depressions that are visible on the outside can be created in the wall of the can packaging in practically any variety. For example, a projection with a semicircular cross-section with a circle radius of 1 mm creates a semicircular depression with a maximum depth of 0.5 mm in the wall of the can packaging. ,

Even these few examples mentioned, which will be explained in more detail below in connection with the preferred embodiments of the invention, show the extreme variety of design options that are created by the device according to the invention.

Another possible variation comes from matching the height of the projection and the thickness of the blank used to produce the can packaging. A recess in the wall of the can packaging is formed only over the partial area of the can packaging, which is formed from the section of the blank that comes into contact with the respective projection. For example, if the projection measured from the die base along the die wall has a height of 1 mm and a blank with a thickness of 2 mm is used to form the can packaging blank, the groove formed by the projection extends over 50% of the can packaging blank starting at the bottom vertical extent of the can packaging blank. If the blank has a thickness of 4 mm, the groove only extends over 25% of the vertical extent of the can packaging blank. The reason for this is that the material with a thickness of 3 mm does not come into contact with the projection at all, so it cannot form a corresponding depression.

If you were to use a 1 mm thick blank with a 1 mm high projection, the depression would extend over the entire length of the can packaging blank in the longitudinal direction. However, this is not desirable since depressions in the area of the open end of the can packaging blank facing away from the bottom of the can packaging blank are associated with significant disadvantages. As is known to those skilled in the art, a can packaging blank is provided with a tapered shoulder and a rolled edge at its open end during its further processing into a can packaging. The rolled edge is used for the subsequent attachment of a closure cap, a dosing device or another applicator of any design. However, a tight connection between the cap and the cap is absolutely necessary Can packaging, as it must be prevented that the contents escape unintentionally. Such a tight connection can only be ensured if the outside of the wall of the can packaging blank is smooth in the area intended to form the shoulder and rolled edge.

In all embodiments of the present invention, the predetermined height of a projection corresponds to the maximum extent of the projection in a direction parallel to the die wall. The height of a projection can of course vary over the width and also over the depth of the projection. By stating that the height of a specific projection corresponds to the maximum extent of the projection in a direction parallel to the die wall, this height is clearly defined.

According to the invention, the height of the projection provided in the area of the die wall adjacent to the die base or the height of the projections provided is a maximum of 95% of the die wall height. This limitation ensures that the area of the can packaging blank, which is intended to form the shoulder and the rolled edge of the can packaging, does not have any depression or relief-like structure on the outside of its wall. The smooth, continuous outside in this area ensures a tight connection between the cap and the can packaging.

It should be noted that, by strict definition, a score is a surface imperfection that is a linear depression with a rounded or flat base. In contrast, a crack has a sharp base and grooves are created by the ideal geometric shape of the tool cutting edge. As already stated, the different shape of the projection or projections provided on the die wall can produce an extremely large variety of depressions on the outside of the can packaging blank, which are referred to as the “relief-like design” of this outside. All structuring of the wall of the can packaging blank that is visible on the outside as a depression is referred to as “striations” in the context of the present text, regardless of their specific design and regardless of the definitions cited above.

The die wall preferably has several projections in its area adjacent to the die base. As already stated, this embodiment significantly increases the possible variations in the design of the structure of the outside of the can packaging blank and a can packaging made from it. It should be made clear that over the circumference of the die wall a number of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 , 28, 29, 30, .... projections can be provided.

If several projections are provided, any number of projections can have the same width, height, depth and cross-section, while another group of projections can also have the same width, height, depth and cross-section, but which differ from those of the first group. It is also possible for all of the projections to have different widths and/or different heights and/or different depths and/or different cross-sections. In principle, any combination of projections can be selected, each of which has a specific width, height, depth and cross section. However, the height of each of the projections provided in the area of the die wall adjacent to the die base may be a maximum of 95% of the die wall height.

The width of a particular projection in all embodiments of the present invention corresponds to the maximum extent of the projection in a direction parallel to the die bottom. Since the die wall usually has a curvature in a plane parallel to the die base and it can be advantageous to equip the projection with the same curvature, the width of the projection in these cases corresponds to the length of a line curved according to the curvature of the die wall. It is clear to the person skilled in the art that in principle there are an infinite number of directions parallel to the die base, and also that a specific projection can be described by a large number of the curved lines mentioned, by the statement that the width of a specific projection corresponds to the maximum extent of the projection, However, this width is clearly defined. Even if the projection has any shape and varies in width over its height, its maximum width can be specified.

In all embodiments of the present invention, the height of a particular projection corresponds to the maximum extent of the projection in a direction parallel to the die wall. The height of a projection can of course vary over the width and also over the depth of the projection. By stating that the height of a specific projection corresponds to the maximum extent of the projection in a direction parallel to the die wall, this height is clearly defined.

The depth of a particular projection in all embodiments of the present invention corresponds to the maximum extent of the projection in a direction perpendicular to the die wall. The depth of a projection can of course vary over the width and also over the height of the projection. By stating that the depth of a given protrusion is the maximum extent of the protrusion in a This depth corresponds to the direction perpendicular to the die wall, but is clearly defined.

In principle, the projections or a single projection can have any width, which is only limited by the circumference of the can packaging blank produced with the help of the die. The width of a projection can therefore be, for example, a quarter, a third or even half of the circumference of the can packaging blank. The projections preferably have a width of 0.1 mm to 10 mm, particularly preferably 0.5 mm to 5 mm and particularly preferably 1 mm to 2.5 mm. If several projections are provided, any number of projections can have an identical first width, which is for example in the range between 1.5 mm and 2 mm, while another group of projections can have an identical second width, but which differs from that first width and is, for example, in the range between 2 mm and 2.5 mm. In this embodiment, the two groups of projections and thus also the two groups of grooves in the wall of the can packaging can be designed opposite one another as sections with grooves of the same width. However, grooves of different widths can also alternate one after the other. It is also possible for all of the projections to have different widths. In principle, any combination of projections can be selected, each of which has a specific width. It is obvious to the person skilled in the art that simply because of the variation in the width of the projections, an almost infinite variety opens up for a relief-like design of the outside of the can packaging blank and the can packaging made from it. The number of groups of grooves of the same width is only limited by the size of the can packaging.

The projections preferably have a height of 0.1 mm to 30 mm, particularly preferably 0.5 mm to 10 mm and particularly preferably 1 mm to 5 mm. If several projections are provided, any number of projections can have an identical first height, for example in the range between 2 mm and 3.5 mm, while another group of projections can have an identical second height, but which differs from that first height and is, for example, in the range between 3.5 mm and 4.5 mm. Since a specific can packaging blank is made from a specific blank which has a specific thickness, projections of different heights in the wall of the can packaging blank create grooves of different lengths in the longitudinal direction of the can packaging blank. In this embodiment, the two groups of projections mentioned and thus the two groups of grooves in the wall of the can packaging can be opposite one another as sections with grooves of each be of the same length. However, grooves of different lengths can also alternate one after the other. It is also possible for all of the projections to have different heights. In principle, any combination of projections can be selected, each of which has a specific height. It is obvious to the person skilled in the art that simply because of the variation in the height of the projections, an almost infinite variety opens up for a relief-like design of the can packaging blank and the can packaging made from it. The number of groups of grooves of the same height is only limited by the size of the can packaging. The height of the projections can also be varied continuously according to a specific pattern, whereby, for example, grooves of different lengths are created around the entire circumference of the can packaging blank or the can packaging, which, in their sequence, reproduce a wave pattern, for example. The projections preferably have a depth of 0.01 mm to 1 mm, particularly preferably 0.05 mm to 0.5 mm and particularly preferably 0.1 mm to 0.25 mm. If several projections are provided, any number of projections can have an identical first depth, which is for example in the range between 0.15 mm and 0.2 mm, while another group of projections can have an identical second depth, which however differs from the first depth and is, for example, in the range between 0.2 mm and 0.25 mm. In this embodiment, the two groups of projections and thus also the two groups of grooves in the wall of the can packaging can be designed opposite one another as sections with grooves of the same depth. However, grooves of different depths can also alternate one after the other. It is also possible for all of the projections to have different depths. In principle, any combination of projections can be selected, each of which has a specific depth. It is obvious to the person skilled in the art that simply because of the variation in the depth of the projections, an almost infinite variety opens up for a relief-like design of the can packaging blank and the can packaging made from it. The number of groups of grooves of the same depth is only limited by the size of the can packaging.

The projections provided in the area of the die wall adjacent to the die base have a cross section parallel to the die base, the cross section being designed in the shape of a segment of a circle, in particular semicircular. In principle, the circular segment-shaped cross section of the projections can be chosen practically arbitrarily within technical limits that are obvious to those skilled in the art. The cross sections mentioned result in grooves that have a particularly demanding tactile and optical appearance and are therefore preferred in the context of the present invention.

The projections are preferably arranged circumferentially over the entire circumference of the die wall. In this embodiment, the can packaging blank produced with the help of the die and the can packaging produced from it have a haptically and visually similar or even identical impression over the entire circumference. However, it can also be preferred for other purposes to concentrate the projections in a specific portion of the die wall and thus the grooves in a specific portion of the can packaging blank or the can packaging.

The press ram preferably has a circumferential bead in its edge region adjacent to the die base in the state of use. The thickness of the wall of the can packaging blank is defined by the gap remaining between the bead and the die wall. In the area of a projection of the die wall, the gap remaining between the bead and the projection defines the thickness of the wall of the can packaging blank in the area of a groove.

The can packaging blank and also the can packaging produced from it can in principle have a horizontal cross-section that is chosen practically arbitrarily within technical limitations that are obvious to the person skilled in the art. This cross section corresponds to the cross section of the die wall parallel to the die base. Can packaging blanks very often have the shape of a hollow, vertical circular cylinder. According to a preferred embodiment of the present invention, the die bottom forms a hollow, vertical circular cylinder with the die wall. The diameter of this circular cylinder parallel to the die base is preferably between 10 mm and 120 mm. An oval cross section of the can packaging blank parallel to the die base is also easy to implement and visually appealing. The same applies to a rectangular, square, triangular or generally polygonal cross section. However, it should be emphasized again that basically any conceivable cross-sectional shape is possible.

1. a) Bereitstellen einer Vorrichtung zur Herstellung eines Dosenverpackungsrohlings durch Rückwärtsfließpressen mit Gesenk und Pressstempel wie sie oben beschrieben wurde,
2. b) Einlegen einer Ronde in das Gesenk,
3. c) Einführen des Pressstempels und Ausüben eines Pressdruckes auf die Ronde,
4. d) Entnehmen des Dosenverpackungsrohlings aus dem Gesenk.

The present invention also includes a method for producing a can packaging blank by reverse extrusion comprising the steps

1. a) providing a device for producing a can packaging blank by backward extrusion with a die and press punch as described above,
2. b) inserting a blank into the die,
3. c) inserting the press punch and applying pressing pressure to the blank,
4. d) Removing the can packaging blank from the die.

All of the advantages and special features mentioned in connection with the various embodiments of the device according to the invention for producing a can packaging blank by reverse extrusion also apply in the same way to the method according to the invention for producing a can packaging blank by reverse extrusion. To avoid repetition, please refer to the relevant statements above.

The diameter of the blank is preferably chosen so that the blank rests in its edge area on the projections after being inserted into the die before the press punch is inserted. The press stamp is then inserted into the die and exerts pressure on the blank. The blank material is then first pressed down to the die base and is then in contact with these projections via the height H of the projections.

According to a particularly preferred embodiment, the projections provided in the area of the die wall adjacent to the die base have a predetermined height, the predetermined height being a maximum of 95% of the thickness of the blank. Particularly preferred are embodiments in which the projections provided in the area of the die wall adjacent to the die base have a predetermined height, the predetermined height being a maximum of 75%, particularly preferably a maximum of 50%, of the thickness of the blank. Also preferred are embodiments in which the projections provided in the area of the die wall adjacent to the die base have a predetermined height, the predetermined height being at least 5%, preferably at least 15%, particularly preferably at least 25% of the thickness of the blank.

It should be clarified that the preferred embodiments described here relate to advantageous variants of a method for producing a can packaging blank by reverse extrusion, which is carried out using an apparatus for producing a can packaging blank by reverse extrusion with a die and press punch as described above. The limitation provided for in the invention, according to which the height of the projection provided in the area of the die wall adjacent to the die base or the height of the projections provided is a maximum of 95% of the die wall height, is therefore also met in any case when carrying out the method for producing a can packaging blank by backward extrusion . As already stated, this limitation ensures that the area of the can packaging blank, which is intended to form the shoulder and the rolled edge of the can packaging, has no depression or relief-like structure on the outside of its wall. The smooth, continuous outside achieved in this way allows for a tight connection Cap and can packaging must be ensured. In practice, however, it is often easier to set the height of the projections in relation to the thickness of the blank used. This makes it possible to quickly and easily determine the range in which the thickness of a blank may lie that is to be used in a specific die equipped with a plurality of specifically designed projections of a predetermined height.

As already stated, there is a possibility of variation for the shape of the grooves in the can packaging blank by matching the height of the projection or projections and the thickness of the blank used to produce the can packaging. The relief-like structure in the wall of the can packaging blank is formed only over the partial area of the can packaging blank, which is formed from the section of the blank that comes into contact with the projections. For example, if the projection measured from the die base along the die wall has a height of 2 mm and a blank with a thickness of 3 mm is used to form the can packaging blank, the groove formed by the projection extends over 66% of the can packaging starting at the bottom vertical extent of the can packaging. If the blank is 4 mm thick, the groove only extends over 50% of the vertical extent of the can packaging. The reason for this is that the material with a thickness of 2 mm does not come into contact with the projections at all, and therefore cannot form a corresponding depression.

If one were to use a blank with a thickness corresponding to the height of the projections or even a smaller thickness, the grooves formed in the wall of the can packaging would always extend over the entire length of the can packaging in the longitudinal direction. However, as already stated, such embodiments have disadvantages and are not desirable.

According to a further preferred embodiment, the blank used in the method according to the invention or the blank used together with the device according to the invention consists of metal, in particular aluminum, an aluminum alloy or copper. Reverse extrusion processes can be carried out particularly well and advantageously with suitable metals known to those skilled in the art. Aluminum and copper are particularly suitable and aluminum is particularly preferred. Of course, any type of suitable metal alloy known to those skilled in the art, in particular aluminum alloy, can also be used. The person skilled in the art usually selects the material of the blank depending on the properties desired for the finished can packaging.

The present disclosure also includes a can packaging blank having a major axis defining a longitudinal direction and a wall having an outside and an inside. The wall of the can packaging blank has a variable wall thickness at least over a portion of the can packaging blank that extends in the longitudinal direction. The portion of the can packaging blank with variable wall thickness extends from the bottom of the can packaging blank over a maximum of 95% of the height in the longitudinal direction of the can packaging blank. The variable wall thickness is caused by the fact that only the outside of the wall is designed in relief.

The partial area of the can packaging blank therefore extends with a variable wall thickness starting from the bottom of the can packaging blank over a maximum of 95% of the height in the longitudinal direction of the can packaging blank. As already stated in connection with the device and the method according to the present invention, this limitation ensures that the area of the can packaging blank, which is intended for the subsequent formation of the shoulder and the rolled edge of the can packaging, does not have any recess or relief-like structure on the Has the outside of its wall. The smooth, continuous outside in this area ensures a tight connection between the cap and the can packaging.

As also already stated, the very fundamental advantage of the method according to the invention and the device according to the invention is that, in contrast to the can packaging known from the prior art with a structured outer surface, the structuring of the outer surface caused by the device according to the invention for producing a can packaging blank occurs directly during the manufacturing process by backward extrusion by varying the wall thickness of the can packaging blank. The projection provided in the area of the die wall adjacent to the die base causes the metal flowing backwards in the area of the projection to create a recess in the wall of the can packaging blank that is being formed, which is shaped in accordance with the shape of the projection. However, such a depression that is visible on the outside of the can packaging blank has no equivalent in the form of an elevation on the inside of the wall of the can packaging blank. This remains smooth and continuous like can packaging without any structuring on the outside. Can packaging blanks and subsequently can packaging are therefore formed which have a discontinuous or variable wall thickness in their cross-sectional area at least over a partial area extending in the longitudinal direction, the variable wall thickness being caused by the fact that only the outside of the wall is designed in a relief-like manner. Such Can packaging or can packaging blanks are not known from the prior art, regardless of the process used to produce them.

It should be emphasized again that the variable wall thickness is caused by the fact that only the outside of the wall is designed in relief. The inside of the wall of the can packaging blank, however, remains unchanged, i.e. it is smooth and continuous, like a can packaging without structuring on the outside. This applies regardless of the cross-sectional area of the can packaging blank. As already stated, the die base can be circular, oval, rectangular, square, triangular or polygonal, with the die wall being arranged vertically on the die base. This means that the cross section of the die parallel to the die base can also have a circular, oval, rectangular, square, triangular or polygonal shape. It is clear to the person skilled in the art that can packaging blanks can be produced in an analogous variety of shapes with the help of such devices. A cross-sectional area of the can packaging blank arranged perpendicular to the main axis HA of the can packaging blank can accordingly have not only a circular shape, but also an oval, rectangular, square, triangular or polygonal shape. What all embodiments have in common is the fact that the variable wall thickness is caused exclusively by a relief-like design on the outside of the wall. The statement that the inside of the wall of the can packaging blank is smooth and continuous therefore means, for example in the case of a circular cross section, that the inside of the wall has a constant curvature. In the case of a square cross-section, the term "continuous" does not refer to the entire inside, since there can be no question of a "continuous" transition at the edges of the square. In this case, "smooth and continuous" or "steady" refers to each of the four interior surfaces of the square.

Generally speaking, the feature that “only the outside of the wall is designed in relief” also includes the statement that such a relief-like design does not exist on the inside of the wall. There are no depressions, elevations or other structures on the inside.

Preferably, the portion of the can packaging blank with variable wall thickness extends, starting from the bottom of the can packaging blank, over a maximum of 90%, preferably a maximum of 85%, particularly preferably a maximum of 80%, particularly preferably a maximum of 75% and most preferably a maximum of 50% of the height in the longitudinal direction of the can packaging blank .

Also preferred are embodiments in which the portion of the can packaging blank with variable wall thickness extends from the bottom of the can packaging blank over at least 5%, preferably at least 15%, particularly preferably at least 25% of the height in the longitudinal direction of the can packaging blank.

Particularly preferred in the context of the present disclosure are can packaging blanks whose relief-like design on the outside of the wall is caused by groove-like depressions in the outside. It should be mentioned again that in all cases the inside of the wall is continuous.

Particularly preferably, the groove-like depressions extending from the outer surface into the wall of the can packaging blank run parallel to the main axis (HA) of the can packaging blank.

The present disclosure also includes a can packaging blank made using any of the above-described apparatus for producing a can packaging blank by reverse extrusion.

The present disclosure also includes a can packaging blank made by one of the methods described above for producing a can packaging blank by reverse extrusion.

Finally, the present invention also includes a can packaging manufactured using one of the can packaging blanks described above. Starting from a can packaging blank produced according to an embodiment of the present disclosure, in order to produce the finished can packaging, only the steps known to those skilled in the art, such as the formation of the shoulder and crimping the opening of the can packaging blank facing away from the can packaging base, need to be carried out to form a rolled edge. Further developments, advantages and possible applications of the invention also emerge from the following description of exemplary embodiments and from the figures.

Brief description of the drawings

Fig. 1

in schematischer Darstellung einen vertikalen Schnitt durch ein aus dem Stand der Technik bekanntes Gesenk;

Fig. 2

in schematischer Darstellung einen vertikalen Schnitt durch eine erfindungsgemäße Vorrichtung zur Herstellung eines Dosenverpackungsrohlings durch Rückwärtsfließpressen;

Fig. 3A

in schematischer Darstellung in seitlicher Draufsicht ein erfindungsgemäßes Gesenk;

Fig. 3B

in schematischer Darstellung in Draufsicht einen Ausschnitt des Gesenks gemäß Fig. 3A;

Fig. 4A

in schematischer Darstellung in seitlicher Draufsicht einen durch die Erfindung hergestellten Dosenverpackungsrohling;

Fig. 4B

in schematischer Darstellung einen vergrößerten Ausschnitt eines Schnitts entlang der Ebene A-A der Fig. 4A;

Fig. 5

in schematischer Darstellung in seitlicher Draufsicht eine erfindungsgemäße Dosenverpackung hergestellt aus dem Dosenverpackungsrohling gemäß Fig. 4A.

The invention will be explained in more detail below using exemplary embodiments in connection with the drawings. Show it

Fig. 1

a schematic representation of a vertical section through a die known from the prior art;

Fig. 2

a schematic representation of a vertical section through a device according to the invention for producing a can packaging blank by backward extrusion;

Fig. 3A

a schematic representation in a side plan view of a die according to the invention;

Fig. 3B

in a schematic representation in plan view of a section of the die according to Fig. 3A ;

Fig. 4A

a schematic representation in a side plan view of a can packaging blank produced by the invention;

Fig. 4B

in a schematic representation an enlarged section of a section along the plane AA Fig. 4A ;

Fig. 5

in a schematic representation in a side plan view of a can packaging according to the invention made from the can packaging blank according to Fig. 4A .

Ways of carrying out the invention

The Figure 1 shows a schematic representation of a vertical section through a die 2 known from the prior art. Shown are the press ram 3, the die 2 with the die bottom 2.1 and the die wall 2.2. The press stamp 3 has a circumferential bead 5.

In the left part of the Figure 1 the press ram 3 is shown at a distance from the die 2, i.e. the situation before the can packaging blank is formed. The blank 6 is inserted into the die 2.

In the right part of the Figure 1 the press stamp 3 is inserted into the die 2 and exerts pressure on the blank 6. This pressure stress results in a deformation of the blank 6, which flows upwards in the opposite direction to the direction of stamp movement. Through the The gap remaining between the circumferential bead 5 of the press ram 3 and the die wall 2.2 defines the wall thickness of the can packaging blank formed by backward extrusion.

The Figure 2 shows a schematic representation of a vertical section through a device according to the invention for producing a can packaging blank by backward extrusion. The representation is similar to that in the left part of the Figure 1 shown, known from the prior art device. Shown are the press ram 3, the die 2 with the die base 2.1 and the die wall 2.2. The press stamp 3 has a circumferential bead 5. The die wall 2.2 has, in its area adjacent to the die base 2.1, several projections 4 with a width of 1 mm, a height H of 1.5 mm, a depth of 0.15 mm and a trapezoidal cross-section parallel to the die base 2.2.

The blank 6 is inserted into the die 2. The blank 6 is made of aluminum and has a thickness HR of 4.5 mm. The height of the die wall HG is 6 mm. The height of the projections 4 is therefore 25% of the height of the die wall. The blank 6 rests on the projections 4 before the press punch 3 is inserted. The press stamp 3 is then inserted into the die 2 and exerts pressure on the blank 6. The blank material is then first pressed down to the die base 2.2 and is then in contact with the projections 4 over a height H of 1.5 mm. Since the thickness HR of the blank is a factor of 3 greater than the height H of the projections 4, the groove-like depressions in the wall of the can packaging blank formed in this way by backward extrusion extend over a third of the extent of the can packaging blank in the longitudinal direction LR (see Figure 4A ).

The Figure 3A shows a schematic representation in a side plan view in detail of a die 2 according to the present invention. The die 2 is shown with the die base 2.1 and the die wall 2.2. The die wall 2.2 has a large number of projections 4 in its area adjacent to the die bottom 2.1. The projections 4 have a width B of 5 mm, a height H of 10 mm, a depth of 0.15 mm and a trapezoidal cross-section parallel to the die base 2.2 (the trapezoidal cross-section is not part of the present invention, but the cross-section in the shape of a segment of a circle). . The edges of the projections 4 adjacent to the die base 2.1 are chamfered, so they do not project vertically from the die wall 2.1, but rather run at an angle of around 45 ° relative to the die wall 2.1.

From the schematic representation in the Figure 3B Section of the die shown in plan view Figure 3A the depth T of the projections 4 can be seen to be 0.15 mm.

All projections 4 in the Figures 3A and 3B shown embodiment of the die according to the invention have the same height, width, depth and the same cross section and are arranged equidistantly spaced from one another and evenly distributed around the entire circumference of the die wall.

The Figure 4A shows a schematic representation in a side plan view of a can packaging blank 10 produced by the invention. In Figure 4B is a schematic representation of an enlarged section of the section along plane AA Figure 4A shown. The can packaging blank 10 has a main axis HA defining a longitudinal direction LR and a cross-sectional area arranged perpendicular to the main axis HA, the wall 12 of the can packaging blank 10 having an outside 12.1 and an inside 12.2. Over a partial area TB of the can packaging blank 10 extending in the longitudinal direction LR, the wall 12 in the cross-sectional area of the can packaging blank 10 has a variable wall thickness WD, which is caused by groove-like depressions 11 in the outer surface 12.1, the inner surface 12.2 over the area of the groove-like depressions 11 runs continuously. The depth T of the groove-like depressions 11 corresponds to the depth T of the projections 4 of 0.15 mm (see Figure 3B ).

The grooves 11 of the can packaging blank 10 formed by the projections 4 of the die 2 have the same height, width, depth and the same cross section and are arranged equidistantly from one another and evenly distributed around the entire circumference of the can packaging blank 10.

The Figure 5 shows a schematic representation in a side plan view of a can packaging 20 according to the invention made from the can packaging blank 10 according to Figure 4A . Starting from the can packaging blank 10 according to Figure 4A In order to produce the finished can packaging 20, only the post-processing of the opening of the can packaging blank 10 facing away from the can packaging base, which is known to those skilled in the art, was carried out. This includes, for example, the formation of the can shoulder and the crimping of the can packaging wall at its opening to form the rolled edge 21.

Reference symbol list

1

contraption

2

die

2.1

Die base

2.2

Die wall

3

Press stamp

4

head Start

5

bead

6

Ronde

10

Can packaging blank

11

groove-like depressions

12

wall

12.1

Outer surface of the wall

12.2

Inner surface of the wall

20

Can packaging

21

bead

b

Width of the projection

H

Height of the projection

T

Depth of protrusion

HG

Height of the die wall

MR

Thickness of the blank

HA

Main axis of the can packaging blank

LR

Longitudinal direction

TB

Part of the can packaging blank

WD

Wall thickness of the can packaging blank

Claims (15)

1. Device (1) for the production of a tin packaging blank (10) by means of reverse extrusion, wherein the device comprises a die (2) and a punch (3), wherein the die (2) comprises a die base (2.1) and a die wall (2.2) with a die-wall height (HG), wherein the die wall (2.2) comprises in its area adjacent to the die base (2.1) at least one projection (4) with a predetermined width (B), a predetermined height (H), a predetermined depth (T) and a predetermined cross-section, wherein the height (H) of the projection (4) is at most 95 % of the die-wall height (HG), characterized in that the cross-section of the at least one projection (4) parallel to the die base (2.1) comprises a circle-segment-like shape, in particular a semi-circular shape.
2. Device (1) according to claim 1, characterized in that the die wall (2.2) comprises a plurality of projections (4) in its area adjacent to the die base (2.1).
3. Device (1) according to claim 1 or 2, characterized in that the projections (4) have different widths (B) and/or different heights (H) and/or different depths (T) and/or different cross-sections, wherein the height (H) of the projections (4) is at most 95 % of the die-wall height (HG) in each case.
4. Device (1) according to any one of claims 1 to 3, characterized in that the projections (4) have a width (B) from 0.1 mm to 10 mm, preferably from 0.5 mm to 5 mm, particularly preferably, from 1 mm to 2.5 mm.
5. Device (1) according to any one of claims 1 to 4, characterized in that the projections (4) have a height (H) from 0.1 mm to 30 mm, preferably from 0.5 mm to 10 mm, particularly preferably, from 1 mm to 5 mm.
6. Device (1) according to any one of claims 1 to 5, characterized in that the projections (4) have a depth (T) from 0.01 mm to 1 mm, preferably from 0.05 mm to 0.5 mm, particularly preferably, from 0.1 mm to 0.25 mm.
7. Device (1) according to any one of claims 1 to 6, characterized in that the projections (4) are arranged all around the entire circumference of the die wall (2.2).
8. Device (1) according to any one of claims 1 to 7, characterized in that the die base (2.1) is circular, oval, rectangular, square, triangular or polygonal, wherein the die wall (2.2) is arranged vertically on the die base (2.1).
9. Method for producing a tin packaging blank (10) by reverse extrusion, comprising the steps

   a) providing a device (1) according to claims 1 to 8,

   b) inserting a circular blank (6) with a thickness (HR) into the die (2),

   c) inserting the press punch (3) and exerting pressure on the circular blank (6);

   d) removing the tin packaging blank (10) from the die (2).
10. Method according to claim 9, characterized in that the projections (4) provided in the area of the die wall (2.2) adjacent to the die base (2.1) have a predetermined height (H), wherein the height (H) is at most 95 % of the thickness (HR) of the circular blank (6), preferably at most 75 %, particularly preferably at most 50 % of the thickness (HR) of the circular blank (6).
11. Method according to any one of the claims 9 or 10, characterized in that the projections (4) provided in the area of the die wall (2.2) adjacent to the drop base (2.1) have a predetermined height (H), wherein the predetermined height (H) is at least 5 %, preferably at least 15 %, particularly preferably at least 25 % of the thickness (HR) of the circular blank (6).
12. Tin packaging (20) produced by using a backward-extruded tin packaging blank (10), wherein the tin packaging blank (10) comprises a main axis (HA) defining a longitudinal direction (LR) and a wall (12) comprising an outer side (12.1) and an inner side (12.2), wherein the wall (12) comprises a variable wall thickness (WD) over at least one section (TB) of the tin packaging blank (10) extending in the longitudinal direction (LR), wherein the section (TB) of the tin packaging blank (10) with variable wall thickness (WD) extends from the base of the tin packaging blank (10) over a maximum of 95 % of the height in the longitudinal direction (LR) of the tin packaging blank (10), and that the variable wall thickness (WD) is caused by the fact that only the outer side (12.1) of the wall (12) has a relief-like configuration, wherein the relief-like configuration of the outer side (12.1) of the wall (12) consists of groove-like recesses (11), characterized in that the groove-like recesses (11) comprise a cross-section with a circle-segment-like shape, in particular a semi-circular shape.
13. Tin packaging (20) according to claim 12, characterized in that the segment (TB) of the tin packaging blank (10) with variable wall thickness (WD) extends from the base of the tin packaging blank (10) over a maximum of 75 %, preferably over a maximum of 50 % of the height in the longitudinal direction (LR) of the tin packaging blank (10).
14. Tin packaging (20) according to any one of the claims 12 or 13, characterized in that the section (TB) of the tin packaging blank (10) with variable wall thickness (WD) extends from the base of the tin packaging blank (10) over at least 5 %, preferably at least 15 %, particularly preferably at least 25 % of the height in the longitudinal direction (LR) of the tin packaging blank (10).
15. Tin packaging (20) according to any one of the claims 12 to 14, characterized in that the groove-like recesses (11) run parallel to the main axis (HA).

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