EP1843946A1

EP1843946A1 - Stackable flat bottomed can

Info

Publication number: EP1843946A1
Application number: EP06705897A
Authority: EP
Inventors: Willem Leendert Pieter Van Dam; Bertold Bast; Norbert Mertens; Jan Driessens; Maril Kamp
Original assignee: Ball Packaging Europe Holding GmbH and Co KG; Ball Packaging Europe GmbH
Current assignee: Ardagh Metal Packaging Germany GmbH
Priority date: 2005-02-05
Filing date: 2006-02-03
Publication date: 2007-10-17
Anticipated expiration: 2026-02-03
Also published as: EP1843946B1; DE502006007417D1; US20090090646A1; ATE473926T1; PL1843946T3; ES2348096T3; WO2006081810A1

Abstract

The aim of the invention is to provide the opportunity to alternately produce (according to need) beverage cans forming a single part in the body thereof and metal cans, particularly for baby food or children's food, milk foods or condensed milk, on the same production line while, at the same time, offering considerable savings in terms of material in the latter-mentioned food sector. The invention provides for a metal can that is made of a seamless sheet-metal can body, comprising a body part and a substantially flat bottom formed in a single part therewith, wherein the body part is drawn inwardly towards the bottom and towards the open end thereof in a respectively conical manner. The substantially flat bottom has an outward-pointing bead or inner dent for stackedly receiving a joint connecting one end of the body part of the can of a second, identical metal can to the lid thereof.

Description

Stackable flat bottom box

The invention relates to a metal can made of steel or aluminum, preferably of smaller size, as is customary for baby or infant formula or condensed milk. The metal box is a one-piece box from the sheet types mentioned, with the second part of a lid added, which is attached to a fold at the top of the can (more precisely, the hull or lower part or seamless can body).

Metallic containers or cans were generally made of three parts (so-called three-piece cans) for the stated purposes: a body rolled from sheet hull having a longitudinal seam connecting the axially extending end edges and a bottom and a lid connected respectively to the open ends of the hull a double seam were connected. Although the production is simple and inexpensive, but material-consuming.

Metal cans are already made in two parts and used in particular as beverage cans. For this purpose, the hull and the bottom is made in one piece by stripping (DWI method) and only the lid folded in the usual way. The production is much more difficult and expensive, but much cheaper in terms of material consumption. Because of the difficulties and costs of production, this type of manufacturing is mainly used in the field of high-volume beverage cans, which due to the specialization on beverage cans a production line therefor is sometimes not sufficiently utilized

With the invention, the possibility is to be created, and therein the invention sees its technical task, on the same production line alternately (also according to demand) in the fuselage one-piece beverage cans, alternatively metal cans for baby or baby food in particular, milk formula or condensed milk, while at the same time In the last mentioned food sector, the possibility of significant material savings should be opened up.

This object is achieved according to claim 1, 25 or also for the stacked state according to claim 20. The nature of the production process of the metal can from the manufacture of beverage cans is taken over, so that the production can be carried out on the same production line. However, in particular, the bottom shape is adapted to the other use and then optimized for optimal utilization the volume of space is possible. In addition to a maintained stability and easy and safe stackability of the doses according to the invention is achieved (claim 1, claim 25).

The object is also achieved by alternative uses (claim 26, claim 27) of the filled can according to claim 1 or claim 20. Preferably, condensed milk is a foodstuff as non-carbonated contents for the open can according to claim 1 or the closed can according to claim 20.

The bottom of the can is - in contrast to on the priority day common two-piece beverage cans - designed to be substantially flat. He has no concave or convex curvatures (claim 4). Thus, the filling volume of the small-volume can bodies essentially corresponds to the schematic volume of space of the can (as a cylinder body), which is thus completely available for the filling.

To achieve the dimensional stability, an inert gas can be filled in during the filling of the can and thus a slight internal overpressure can be generated.

A preferred "slight overpressure" is in the range of 0.1 MPa (1 bar), in addition to the external pressure, preferably between 0.8 bar and 1.2 bar over the external pressure, generally assumed to be 1 bar (0.1 MPa) is (claim 22), all at normal outdoor temperature. This should be understood as "easy". This can be seen in relation to the high pressures that can be obtained with carbonated beverage cans between 0.4MPa (4 bar) and 0.8MPa (8bar) in addition to pressure, which a domed vaulted soil can withstand.

The claimed metal cans are small volume (claim 18), but may have different dimensions in terms of axial height, diameter and opening width at the trunk end. Their volume is in the meaning of a "smaller format" in the range between 150ml and 500ml, ie below half a liter, preferably below 330ml. Their height is usually no larger than 120mm, their diameter between 50mm and 75mm.

The axial extent of the conical sections (in the understanding of a portion of a cone, so formed as a truncated cone, but quite "conical") above and below may vary, but they are clearly visible. An area in which the clearly visible conical shapes are dependent on the diameter of the can body. He but can be summarized. Above the cone angle is to settle in the range of 30 + 20% (claim 15). Below the conical surface is inclined in the range between 10 ° and 30 ° (claim 14), each corresponding axial length to allow stacking.

The claimed for the stiffening of the substantially flat bottom surface possibilities for increasing the ground stiffness (claim 5,6,7) can also be replaced by fine ribs or grooves or the like. It is essential that the bottom surface is substantially flat (free of bulges). But he may have staggered annular shoulders as several stages (claim 7).

The floor is stiffened to the extent that an everting to prevent the stability and to block a stackability is avoided. The bottom is still flat, which does not allow it to extend further upward than measured from the support plane, as substantially 5 mm (claim 8). It extends in a height range between the contact plane and the highest point of the bottom surface, usually in the central portion of the bottom, which does not extend further than an intended stacking bead, which is arranged radially within the circumferential Aufstandsrippe (claim 6).

Despite the relatively flat shape of the soil, it is pressure stable, but not to the extent, as a dome-shaped curved bottom. Its pressure stability against evagination or bulging extends to substantially 2 bar, in particular to 3.5 bar (claim 16). For this purpose, sheet thicknesses of the soil are in steel sheet in the range between 0.2 mm and 0.25 mm (claim 17).

The soil stiffness is adapted to the intended use. A terraced formation (claim 9) can be chosen as well as a central planar area which is surrounded by annular corrugations (claim 10).

The method for stacking the seamless can bodies (claim 25) can also be understood as relating to the manufacture of these can bodies. A substantially flat bottom is integrally formed. In each case to the axial end of the can is a conical confinement, both in the lower portion and at the upper end portion. The substantially flat bottom connects to a further outermost bead, which can be named as stacking bead. In the stacking state or stacking, an underlying seam of a second can, which is identical or structurally similar (possibly with different imprint and decoration), engages. stacking one. The same task is fulfilled by the circumferential indentation in the conical confinement, which can be understood as a laterally open groove and can create a folded seam within the inner edge.

A substantially flat cover mirror of a folded lid is lowered relative to the connecting seam and immediately adjoins this seam via a chuck wall projecting axially towards the interior of the fuselage or the closed container (claim 11). The reduction is small. Your measure is smaller than the axial height of the fold (claim 12).

The lid is designed as a tear-open lid with a peripheral line of weakness and a pull-tab, preferably as a full-open lid with round line of weakness near the damping bead (claim 13).

In the stacked state (claim 20), the axially inwardly (to the interior of the sealed container) upstanding bottom bead, which is arranged radially within the lower end of the conical encircling the hull, with a seam seam stacking contact, which belongs to an underlying can. The lower end of the recovery forms the rib (claim 2).

What applies to the towering bottom bead of the above-mentioned fuselage is correspondingly applied to the radially further outward circumferential indentation (as indentation) in the region of the frustoconical constriction of another hull (claim 3).

The circumferentially extending indentation is directly attached radially to the outside of the recess. It is the radially outwardly facing wall or surface of the fin (claim 3), which is formed radially inward and thus "outwardly facing".

Preferably, the upstanding bottom bead or circumferential indentation, while maintaining the axially downwardly extending rib, extends directly from or is at least close to it.

Further advantageous features / properties can be found in the dependent claims and are also explained in connection with the following description of several embodiments. Further features are explained in more detail in connection with the following description of several embodiments. The accompanying figures show

Figure 1 in schematic, containing the axis 100 of the cans

Sectional view of a form of the new metal box on a first embodiment, just before a stacking intervention.

Figure 2 in a similar representation one of the cans of Figure 1 in not yet closed state. The bottom 3 is the same.

3 shows a perspective view of the bottom 3 of the metal can according to FIG. 1

Figure 4 in a similar representation as Figure 2 shows a modified embodiment.

Figure 5 in the same representation as in Figure 4, a further modified embodiment.

The basic shape of the metal cans 1, 1a or 15 made of sheet metal according to Figures 1 to 3 has a seamless hull 2 with integrally formed bottom 3. The hull 2 is tapered at its two end regions (at the upper edge a so-called. Necking, at the bottom of a confiscation to a circumferential ribs). The cone shape is shown at 5 or 11 at the respective axial end region.

The open end 17 of the hull 2 can be closed with a metallic lid 4 via a double seam 12 in the usual way. As a result, the upper closed axial end 2b forms. The production of hull and ground is done in the usual way by drawing (drawn wall ironed, DWI) and brings a significant material savings, as is known from two-piece beverage cans ago. The cover 4 has a "mirror" as a cover panel 4a and a circumferential damping bead 13, which leads into the connecting seam 12 (as, for example, fold). The panel 4a is substantially flat and is lowered from the upper end of the seam 12 and immediately adjoins this seam 12 via the axially downwardly extending bead 13. The can bottom 3 is - in contrast to the priority day common two-piece beverage cans - formed substantially flat. It has no concave or convex curvature. Thus, the filling volume essentially corresponds to the schematic volume of space of the can, which is so fully available for the filling.

At the lower end of the conical confinement 5 of the hull 2 is immediately followed by an axially outwardly projecting rib 6 of small radius of curvature 6a. The bottom sections lying radially within this rib 6 lie at a small distance above the contact surface E formed by the rib. Immediately following the counter-rib 6, there is an axially open bead 7 on the radial inner side thereof. This is - with respect to position and shape of the seam 12 between the opening edge of the fuselage 2 and the lid closing the opening - arranged and dimensioned so that the seam 12 of another, similar can when stacking the metal cans securely received in the bead 7 which contributes to easy and safe stackability. The axial alignment of seam 12 and bead 7 symbolizes the line Y.

This ring plane defined by Y is based on the upper can 1 and the similar lower can 1a. However, it is equally representative of the bead 7 and seam (seam) 12 'on the same can 1. 12 'symbolizes the folding seam, not shown, on the upper box 1. As such, it can also be measured as stackable by itself when placed in a stack composite with "its like", as shown by the beginning of the stacking state according to FIG. This applies equally to the examples of FIGS. 4, 5 presented later.

The bottom area within the bead 7 is terraced and consists of the flat central surface 8 and two likewise flat annular surfaces 9 and 10, which are connected via small steps or shoulders 9a, 10a with each other. The step heights are smaller than the horizontal extensions of the ring surfaces.

Overall, this results in a substantially flat structure of the bottom 3, which has no inwardly projecting bulges. Neither that appear in the center as a dome-shaped bulge, nor those that are distributed over the ground distributed dome-shaped individual curvatures in a composite of several such vaults.

The substantially flat bottom extends in height direction only limited, which explains its small distance from the fin 6. The riot level E is defined by the lowest point of the fin 6, which runs around the stacking bead 7. The small radius of curvature 6a defines the arc defining the axially lower end of the rib 6. Of these, spaced apart in the axial direction (and in the radial direction as well) is the central area 8. These two dimensions define the height range of the floor, which is still considered to be "substantially flat". This height range or difference height is not higher than 10 mm, preferably less than 5 mm, measured from the level E (the lower axial end of the fin) and the highest point of the bottom 3, which corresponds to the central surface area 8 in FIG.

The thickness of the sheet used in this soil is between 0.2 mm and 0.25 mm for steel cans. The bottom is designed, despite the absence of dome-shaped stiffeners, to withstand an internal pressure ranging up to 3.5 bar (0.35 MPa), which is the differential pressure between the internal pressure of a sealed and filled can and the external pressure below the bottom.

This compressive strength refers to a resistance to evasion or buckling, slight variations in the heights of the sections of the terraced floor are quite permitted, the standing and stacking ability must not be affected, however, the maximum movements of the substantially flat soil at its low Height dimension circumscribes. This naturally implies that the bottom also remains stabilized up to essentially 2 bar (0.20 MPa), ie neither evades nor bulges even at lower pressures, based on the same pressure difference, which was called the 3.5 bar number.

The metal cans are small-volume, may have different dimensions with respect to axial height 15a, diameter 15b and opening width 15c at the fuselage neck 17 (axial upper end). Their volume is preferably in the range between 150ml and 500ml. Their height is usually not greater than 120 mm, their diameter between 50mm and 75 mm. The axial extent 6c of the conical constriction 5 of the fuselage 2 at the transition to the ground area can also vary, as can the conical inclination 6b.

The cone taper 6b refers to the axially lower end of the can. It lies in an indicated angle 6b, which can be selected between 10 ° and 30 °, depending on the diameter 15b of the can body. The cone slope at the opposite end, symbolized by 11 in Figure 1 (in the axially downwardly located box), is above the angle at the bottom end and is 30 ° with a span of ± 20%. To achieve dimensional stability, the can may be provided with the food after filling or with an inert gas when filling, which creates a slight internal overpressure. A preferred "slight overpressure" is of the order of 1 bar (0.1 MPa), in addition to the external pressure, preferably between 0.8 bar and 1, 2 bar over the external pressure, which is generally assumed to be 1 bar. The associated wall thickness of the fuselage 2 is in the range between 0.07 mm and 0.09 mm sheet thickness, especially in steel.

FIG. 4 shows a modified design 3a of a bottom region within the standing bead 6 of a can 20, which immediately adjoins the conical surface. Here, too, the central section 22 is smooth and flat. The section 21 between this and the edge bead 6 is weakly wavy or zigzag-shaped in cross section, again connected to the edge bead an outwardly open bead 7, in the - as indicated - the folded seam on the lid 24 of the underlying can is included. On the cover serving for opening grip tab 25 is attached. It can be seen that this bottom 22 is formed substantially flat, without convex or concave bulges. The wavy portion 21 has a plurality of circumferentially extending recesses 23, but which are not a convex / concave bulge in the sense of a dome (Dom) or an eccentric bulge. The amplitudes of the recesses are smaller than the depth of the bead 7. The box 20 has at the upper open end a conical recess 41 with a substantially flat inclined surface. At the fuselage neck 47, a lid can be folded, as shown as a lid 24 in Figure 4.

The container 30 of Figure 5 has an inner bottom surface 35 which corresponds to that of the bottom 3a of Figure 4. Immediately radially within the gutter bead 36 of the can, as previously described, there is an outwardly open bead 38 for possible receipt of the seam of another can.

In this embodiment, on the radial outer surface of the standing bead 36, ie in the region of a conical recess 31, a dent 32 (as a peripheral open bead) is provided, which is arranged and dimensioned so that they provide the provided at the upper end 30b seam 34 between the cover 33rd and can securely hold a lower can 30a with a larger lid diameter.

The circumferential indentation 32 on the radially outer surface of the ridge bead 36 may be present alone or in addition to the peripheral bead 38, the latter the bead 7 corresponds to the previous examples. The ratio of the recesses 41, 31 determines which lid size of a lid 33 is used to achieve stacking. Either by engagement of the seam 34 in the radially outward indentation or by engagement in the radially inwardly located bead 38 (corresponding to 7 of the other examples). Both, the bead 7 and 38 on the one hand and the indentation 32 on the other hand are "facing outward". They can be provided individually or cumulatively.

The possibilities of increasing the soil rigidity, which are shown for the stiffening of the inner floor area, can also be replaced by fine ribs or grooves or the like. The floor still remains essentially flat and free of bulges, which is referred to as a "dome-shaped" concavity in a beverage can.

The comments made on the previous embodiments on the addition of inert gas under pressure to stabilize the wall, the sheet thicknesses, the low height of the substantially flat bottom, the dimensions of the conical recoveries and the pressure stability of the soil are on the Embodiments of Figures 4 and 5 to transfer accordingly. These apply here as well.

Not shown in the drawings are score lines in the lid mirror of a respective lid 4, 24 or 33. They are familiar to the expert and are used to open the lid, so that they are not shown in the drawing. A respective lid has as Aufreißdeckel doing a circumferential line of weakness, which can be broken with the tear tab 25 of Figures 4 or 5, to take out the lid mirror within the circumferential line of weakness. This is common and common prior art, which will not be explained separately here.

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Claims

Claims:

A metal can of a seamless can body (1) made of sheet metal, with a can body (2) and an integrally formed with this - substantially flat - bottom (3, 3a, 35), wherein the hull (2) both to the bottom (3 ) as well as towards its open end (15c) in each conical (5,11; 31, 41) and the substantially flat bottom (3) has an outwardly facing bead (7) or indentation (32), and formed suitable for stacking a connection seam (12; 34) which connects one end (15c) of a can body of a second, identical metal can (1a; 15) to its lid (4).

2. metal can according to claim 1, wherein the axially inwardly projecting bottom bead (7) radially within the lower end of the conical recess (5) of the fuselage (2) is arranged and - preferably to form an axially outwardly projecting rib (6) - from conical confiscation (5) or at least close to it.

3. Metal can according to claim 1, wherein the indentation (32) in the region of the conical (conical) collection (31) of the hull (30) is provided radially outside of a directly adjacent to the collection axially outwardly extending rib (36).

4. Metal can according to one of the preceding claims, wherein the - substantially flat - bottom (3) is free of convex or concave curved bottom portions.

5. Metal can according to one of claims 1 to 4, wherein the - substantially flat - bottom (3) consists of several radially staggered, substantially flat bottom surface sections (8,9,10) consists.

6. Metal can according to one of the preceding claims, wherein the flat

Bottom (3; 3a; 35) extends in a height range defined by an axially upper end of the bead (7) and an axially lower end of a rib (6), in particular in a height range less than 5 mm.

7. metal can according to claim 5, wherein the bottom surface portions are connected to each other via narrow shoulders (9a, 10a) or the like. Steps, in particular the "narrow shoulders" are shorter than a lateral extent of a respective adjacent bottom surface portion, which represents a slight gradation ,

A metal can according to claim 5, wherein the bottom (3; 3a; 35) does not protrude higher axially inwardly than 5 mm as measured from a lower axial end of a rib (6,36).

9. Metal can according to claim 5, wherein the flat Bodenflächen- sections (8,9,10) via shoulders (9a, 10a) are offset in the axial direction against each other, preferably when viewed from radially outside to radially inside in a direction to axially inside.

10. Metal can according to one of claims 1 to 9, wherein the substantially flat bottom (21) outside a bottom center (22; 8) has annularly extending corrugations (23) or the like, in particular with a weak amplitude.

11. Metal can according to one of the preceding claims, wherein a substantially flat cover panel (4a, cover mirror) relative to the connecting seam (12) is lowered and immediately adjoins this seam via an axially inwardly projecting damping bead (13).

12. Metal can according to the preceding claim, wherein the lowering relative to the connecting seam is light, smaller in height than an axial height of a double fold (12).

13. Metal can according to claim 1 or 6, wherein the cover (4,24) is designed as a tear-open with circumferential weakening line and tear-open tab (25).

14. Metal can according to claim 1, wherein the conical confinement (5) to the bottom (3) is between 10 ° and 30 °.

A metal can according to claim 1 or 14, wherein the tapered recess (11, 41) is located at the open end (47) in the range of 30 ° ± 20%.

16. Metal can according to claim 1 or 6, wherein the substantially flat bottom has a compressive strength against bulging or buckling, which extends to substantially 2 bar (0.20 MPa), as a differential pressure against an outside.

17. Metal can according to claim 16, wherein the sheet of substantially flat bottom is between 0.2 mm and 0.25 mm thick.

18. Metal can according to one of the preceding claims, wherein the receiving volume of the can ranges from 150 ml to substantially 500 ml.

19. Metal can according to claim 16, wherein the compressive strength reaches substantially 0.35 MPa.

20 sealed metal can from a seamless can body (1) made of sheet metal, (i) with a can body (2) and an integrally molded with this - substantially flat - bottom (3), and closed with a lid (4,24,33 ), wherein a substantially flat cover panel (4a) of the lid is lowered relative to a connecting seam (12) to the can body; in which

(ii) the cover panel (4a) immediately adjoins the connecting seam via an axially inwardly projecting damping bead (13);

(iii) the hull (2) is inclined towards the bottom (3) as well as towards its lid-closed end (2b) (5, 11; 31, 41);

(iv) the substantially flat bottom (3; 3a; 35) has an outwardly facing bead (7) or indentation (32) for stacking a joint seam (12; 34) of a second, same metal can (1a, 30a) which connecting seam connects an axial end (30b) of the can body which is stacked lower down with its lid (4, 33).

21. Metal can according to claim 20, with features of the box according to one of claims 1 to 19.

22. The metal can according to claim 20, which is filled with a non-carbonated food, and is provided with an internal additional pressure by an inert gas of more than 0.8 bar (0.08 MPa), above an external pressure.

A metal can according to claim 20, wherein the flat bottom (3; 3a; 35) has a maximum height of less than 10 mm above a contact plane (E).

24. Metal can according to claim 20 or 23, wherein the maximum height is less than 5 mm.

Method for producing or stacking one or more metal cans from a seamless can body (1) made of sheet metal, comprising a can body (2) and an essentially flat bottom (3, 3a, 35) formed thereon ), wherein the hull (2) is tapered towards the bottom as well as towards its open end (17) (5, 11; 31, 41) and the essentially flat bottom has an outwardly facing bead (7) or indentation (32), and a lower one

Connecting seam (12; 34) receives, which seam an axial end (17) of a can body of a second, so far the same metal can (1a, 30) with their

Lid (4,33) connects, and the two cans are stacked or stacked.

26. Use of a metal can according to one of the preceding claims for baby food of various kinds.

27. Use of a metal can according to one of the preceding claims under claim 25 for evaporated milk or other milk products.

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