ES2348096T3 - STACKABLE FLAT BACKGROUND CAN. - Google Patents

Abstract

- Metal can constituted of a body of tin (1) of sheet without welds, with a tin trunk (2) and a bottom (3; 3a; 35), essentially flat, formed in a piece with it, being sunk respectively in cone shape (5, 11: 31, 41) the can trunk (2) both towards the bottom (3) and also towards an open end (15c); that the essentially flat bottom (3) has a groove (7) directed outwards or a groove (32), characterized in that it is configured and is suitable for housing by stacking a joint weld (12; 34) that joins one end (15c) of a second tin can of a second metal can (1a; 15) equal with a cover (4) that closes it.

Description

The present invention relates to a metal can of steel or aluminum, preferably of a rather small format, as is customary for baby or baby food or condensed milk. The metal can is a can in a piece of the mentioned types of sheet, presenting as a second part a cover that is placed with a crease on the upper edge of the can (more exactly: the trunk or bottom piece or can body without welding ).

Metal containers or cans have been manufactured for the purposes mentioned in general in three pieces (so-called three-piece cans): of a rolled sheet metal trunk with a longitudinal weld that joins the axially running end edges, as well as a bottom and a cover that join with the open ends of the trunk through respectively a double-fold weld. Manufacturing is simple and economical, however it requires a lot of material.

Two-piece metal cans are also manufactured and used in particular as beverage cans. To do this, the trunk and the bottom are manufactured in one piece by stretching (DWI procedure) and only the cover is folded in the usual way. Manufacturing is clearly more expensive and expensive, but clearly more economical with respect to material consumption. Due to the difficulties and costs of manufacturing, this type of processing is mainly used in the field of cans for beverages made with large-scale manufacturing, sometimes a manufacturing path is not sufficiently used for this due to the specialization in cans for drinks

From GB 1 572 031 a metal can is known, in particular a beverage can according to the preamble of claim 1, which can be stacked. In the case of a lid for such drinks a bulge, which at the same time forms the vertical surface of the beverage can, is present at the bottom of the corresponding beverage can. This bulge with an outer cone is in a position to slide on the edge of the cover of a lower can arranged below an upper can and therefore to produce a stacked joint between the upper and the lower can.

A fixed stack is not possible in similar cans.

From EP 1 103 470 A1 a metal can with a high pressure control element is known, the geometric conformation of the bottom of this can is directed towards the pressure resistance of the can with respect to its elevated internal pressures. A stackability, in particular with respect to the stacking of two cans by a correlation between joint welding and a groove, does not follow from EP 1 103 470 A1.

With the invention the possibility must be created and in this the invention sees its technical objective of manufacturing in the same manufacturing path alternatively (also according to need) on the trunk cans for drinks in one piece, alternatively metal cans for in particular food for children and babies, dairy foods or condensed milk, while at the same time the possibility of considerable material savings in the last mentioned food sector must be opened.

This objective is solved according to claim 1 or also by the stacking state according to claim 20 and 21. According to the character, the manufacturing method of the metal can is adopted from the manufacture of beverage cans, so that the processing can be carried out. in the same manufacturing line. However, the shape of the fund is adapted in particular to another purpose of use and is optimized so as to allow optimum use of space volume. Together with a stability under conserved load, a simple and safe stackability of the cans according to the invention is also achieved (claim 1, claim 25).

The objective is also solved by alternative uses (claim 26, claim 27) of the full can according to claim 1 or claim 20. The condensed milk is preferably a food as a non-carbonated filler for the open can according to claim 1 or closed can according to claim 20.

The can bottom is configured, as opposed to the cans for drinks in two current pieces on the priority day, essentially flat. In this case, it does not have a concave or convex bulge (claim 4). Therefore, the filling volume of the small volume can logs essentially corresponds to the schematic spatial volume of the can (as a cylindrical body) which is thus fully available for filling.

To achieve shape stability, when filling the can an inert gas can be packaged 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 versus the external pressure that can generally be assumed to be 1 bar (0.1 MPa) (claim 22), all with normal outside temperature. Under "light" this should be understood. This can be seen in relation to high pressures, which can originate in the case of cans for carbonated drinks in the case of use between 0.4 MPa (4 bar) and 0.8 MPa (8 bar) with additionally permitted pressure, which allows to resist a domed dome-shaped bottom.

The metal cans tested have a small volume (claim 18), but may have different dimensions with respect to axial height, diameter and opening at the end of the trunk. Its volume is in the concept of a "smaller format" in the range between 150 ml and 500 ml, thus below half a liter, preferably below 330 ml. Its height in general is not more than 120 mm, its diameter is between 50 mm and 75 mm.

The axial spacing of the cone-shaped sections (in the compression of a section of a cone, configured as well as a truncated cone, but completely "cone-shaped") can vary up and down, but they can be clearly seen. A range in which the cone shapes are clearly visible depends on the diameter of the can trunk. But it can be summarized. Above, the angle of the cone surface can be set in the range of 30 ° ± 20% (claim 15). Below the surface of the cone is inclined in the range between 10 ° and 30 ° (claim 14), with corresponding axial length respectively to allow stacking.

The possibilities tested for the reinforcement of the essentially flat bottom surface for increasing the stiffness of the bottom (claim 5, 6, 7) can also be substituted by ribs or fine grooves or the like. In this case it is essential that the bottom surface is essentially flat (free of bulges). But it can have stepped annular projections as several steps (claim 7).

The bottom is in this aspect reinforced and a bulge is avoided to prevent stability and to oppose a stackability. The bottom is still flat, which cannot be extended measured from the contact plane subsequently upward, as essentially 5 mm (claim 8). It extends in the range of heights between the support plane and the highest point of the bottom surface, most of the time in the central section of the bottom that does not go upwards like a planned stacking groove that is arranged radially inside of the peripheral support rib (claim 6).

Despite the relatively flat bottom shape it is stable to pressure, but not to the extent that a curved dome bottom. Its pressure stability against the formation of protuberances or bulges reaches essentially 2 bars, in particular up to 3.5 bars (claim 16). The bottom plate thicknesses used for this are in the case of steel sheet in the range between 0.2 mm and 0.25 mm (claim 17).

The rigidity of the bottom is adapted to the purpose of use. A terrace-shaped configuration (claim 9) can also be chosen as a flat central area that is surrounded by annularly flowing undulations (claim 10).

The method for stacking the can bodies without welding (claim 21) can be understood in a manner that refers to the manufacture of these can bodies. An essentially flat bottom is formed in one piece. With respect to the axial end of the can there is a sinking in the shape of a cone, both in the lower section and also in the upper final section. The essentially flat bottom connects with a groove located more externally and which can be referred to as a stacking groove. In the state of stacking or when stacking, a joint weld located under a second can is placed in a stackable manner which is the same or similar constructively (if necessary with different stamping and decoration). The peripheral groove fulfills the same objective in the cone-shaped sinking that can be understood as a laterally open groove and can be placed within an inner edge of a fold weld.

An essentially flat level of coverage of a folded cover is lowered with respect to the joint weld and connects directly with this weld through a chuck wall that protrudes axially into the trunk or closed container (claim 11 ). The descent is small. Its dimension is smaller than the axial height of the fold (claim 12).

The cover is configured as a cover for rapid opening with a peripheral weakening line and a tongue for rapid opening, preferably as a cover for rapid opening complete with a round weakening line near the damping groove (claim 13).

In the stacked state the bottom groove that protrudes axially inwards (into the closed container) and which is arranged radially outside the lower end of the cone-shaped sinking of the trunk, has stacking contact with a fold weld, which belongs to a can arranged below. The lower end of the subsidence forms the vertical rib (claim 2).

What is valid for the bottom groove protruding from the trunk located above, can be correspondingly used to the peripheral conformation placed radially more externally (as a slit) in the cone-shaped subsidence of another trunk (claim 3).

The conformation that runs peripherally is placed directly radially outside in the subsidence. It is the wall directed radially outward or the surface of the vertical rib (claim 3) that is radially shaped inwardly and therefore "directed outwardly".

The protruding bottom groove or the peripheral conformation, while retaining the vertical rib that protrudes axially downward, preferably starts directly from it or is at least close to it.

Other features / advantageous properties are found in the dependent claims and are also explained in connection with the following description of several embodiments.

Other features are explained in more detail in relation to the following description of several embodiments. The corresponding figures show:

Figure 1 in representation in schematic section, containing the axis 100 of the

cans, a form of a new metal can in a first example of

realization, shortly before a stacking intervention.

Figure 2

in similar representation one of the cans according to figure 1 in the state

not yet closed Background 3 is the same.

Figure 3

in perspective view the bottom 3 of the metal can according to figure 1.

Figure 4

in representation Similary to the figure 2 a example from realization

modified.

Figure 5

the same representation as in Figure 4 another modified embodiment.

The basic shape of the metal cans 1, 1a or 16 of sheet metal according to figures 1 to 3 has a trunk 2 without welding with a bottom 3 formed in one piece. The trunk 2 is sunken in the form of a cone in its two final zones (on the upper edge a so-called necking, on the lower edge a sinking to form a peripheral vertical rib). The conical shape is represented with 5 or 11 in the corresponding axial end zone.

The open end 17 of the trunk 2 can be closed in a usual manner with a metal cover 4 by a double-fold weld. Therefore, the upper closed axial end 2b is formed. The manufacture of the trunk and the bottom is carried out in a usual way by drawing (drawn wall ironed, DWI) and entails a clear saving of material, as is known from the two-piece beverage cans. The cover 4 has a "level" as cover panel 4a and a peripheral damping groove 13 leading to the joint weld 12 (such as fold). The panel 4a is essentially flat and is lowered with respect to the upper end of the weld 12 and connects directly with this weld on the groove 13 projecting axially downwards.

The bottom of the can 3 is essentially flat - as opposed to the beverage cans in two current pieces on the priority day. It has no concave or convex bulges. Therefore, the filling volume essentially corresponds to the schematic spatial volume of the can which is thus fully available for filling.

At the lower end of the sinking 5 in the form of a cone of the trunk 2 a vertical rib 6 is connected directly projecting axially outwards by a small radius of curvature 6a. The radially located bottom sections within this vertical rib 6 are located a small distance above the support plane E formed by the rib. On its radial inner face, a groove 7 open axially outwardly is connected directly below with the support rib 6. In reference to the shape position of the weld 12 between the open edge of the trunk 2 and the cover that closes the opening, This groove is arranged and sized so that the weld 12 of another similar can can be accommodated by stacking the metal cans securely in the groove 7, which contributes to a light and safe stackability. The Y line symbolizes the axial alignment of the weld 12 and groove 7.

This annular plane defined by Y refers to the upper can 1 and the lower can 1a similar. But it is also representative for the groove 7 and seam (crease or weld) 12 ’in the same can 1. 12’ symbolizes the weld of crease not shown in the upper can 1. As such, it can also be measured only as stackable if it is placed in a stacking joint with "peers", as the beginning of the stacking state according to the figure is shown.

1. In the same way, this also applies to the examples shown below in Figures 4, 5.

The bottom area within the groove 7 is configured in the form of a terrace and is made by the central flat surface 8 and two equally flat annular surfaces 9 and 10 that are joined together by small steps or projections 9a, 10a. The heights of steps are smaller than the horizontal extensions of the annular surfaces.

As a whole, there is therefore an essentially flat structure of the bottom 3 that does not have a bulge protruding inwards. Neither those that appear in the center as a dome-shaped bulge, nor those that represent individual domed-shaped bulges spaced apart on the ground in a union of several similar bulges.

The essentially flat bottom extends in this case in the height direction only in a limited way, which explains its small distance from the vertical rib 6. The support plane E is defined by the deepest point of the vertical rib 8 that runs around the stacking groove 7. The small radius of curvature 6a defines the bottom which defines the axially lower end of the vertical rib 6. The central surface 8 is distanced therefrom in the axial direction (and in the radial direction as well). These two measures define the range of heights of the bottom that is still seen as "essentially flat."

This range of heights or differential height is not greater than 10 mm, is preferably below 5 mm, measured from the support plane E (the lower axial end of the vertical rib) and the highest point of the bottom 3 which corresponds to the central surface area 8 in the figure

one.

The thickness of the sheet used in this bottom is in the case of steel cans between 0.2 mm and 0.25 mm. The bottom is configured, despite missing dome-shaped reinforcements resist an internal pressure that reaches the range of up to 3.5 bar (0.35 MPa), this being the pressure difference between the inside pressure of a can closed and full and the outside pressure out of the can.

This pressure resistance refers to the resistance against the formation of a

protuberance or bulging, therefore insignificant oscillations of the position in height of the sections of the bottom in the form of a terrace are allowed, the stability and stackability should not be impaired by that which circumscribes the maximum movements of the essentially flat bottom in its small height. This contains according to the nature that the bottom remains stabilized to essentially 2 bar (0.20 MPa), so in the case of lower pressures neither bulges or bulges occur, referring to the same pressure difference that has been mentioned with the numerical amount 3.5 bar

The metal cans are of small volume, they can have different dimensions referring to the axial height 15a, diameter 16b and opening 15c in the trunk neck 17 (upper axial end). Its volume is preferably in the range between 150 ml and 500 ml. Its height is not generally greater than 120 mm, its diameter is between 50 mm and 76 mm. Also the axial spacing 6c of the cone-shaped sinking 5 of the trunk 2 in the transition zone towards the bottom zone can vary even as the inclination of the cone 6b.

The inclination of the cone refers to the axially lower end of the can. It is placed at a drawn angle that can be chosen between 10º and 30º depending on the diameter 15b of the can trunk. The inclination of the cone at the opposite end, symbolized with 11 in Figure 1 (in the can arranged axially below) is located above the angular inclination at the lower end and amounts to 30 ° with a margin of ± 20%.

To achieve shape stability, the can after filling with the food or during filling can be provided with an inert gas that generates a slight internal overpressure. A preferred "slight overpressure" is in the order of magnitude of 1 bar (0.1 MPa), in addition to the external pressure, preferably between 0.8 bar and 1.2 bar with respect to the external pressure that can be assumed in general 1 bar The corresponding wall thickness in this case of the trunk 2 is in the range between 0.07 mm and 0.09 mm of sheet thickness, in particular in the case of sheet steel.

Figure 4 shows a modified configuration 3a of a bottom area within the vertical groove 6 of a can 20 that connects directly with the conical surface. Also here the central section 22 is smooth and flat. The section 21 between the latter and the vertical groove 6 is weakly corrugated or is zig-shaped in cross-section, again connecting with the vertical groove 7 an open groove 7 in which, as indicated, the welding of fold is housed in cover 24 of the can located below. The grip tab 25 used for opening is mounted on the cover. It can be seen that also this bottom 22 is configured essentially flat without concave or convex bulges. The undulating section 21 has several depressions 23 that run peripherally but are not concave / convex bulges in the sense of a dome (or dome) or an offset bulge. The amplitudes of the depressions are smaller than the depth of the groove 7. The can 20 has a cone-shaped collapse 41 with an essentially flat inclined surface at the upper open end. In the trunk neck 47 a cover can be folded as shown in Figure 4 as cover 24.

The container 30 according to Figure 6 has an inner bottom surface 35 corresponding to that of the bottom 3a according to Figure 4. Directly radially inside the vertical groove 36 of the can is located, as already described above, a groove 38 open outward for possible weld housing of another can.

In this embodiment, a groove 32 (as a marginally open groove) that is arranged or sized so that it can be provided is provided on the radial outer surface of the support groove 36, that is, in the area of a cone-shaped subsidence 31 securely housing the weld 34 provided at the upper end 30b between the cover 33 and a can 30a located below with a larger cover diameter.

The peripheral groove 32 on the radial outer surface of the support groove 36 may be present alone or in addition to the peripheral groove 38, which corresponds to groove 7 of the preceding examples. The relationship of the subsidence 41, 31 determines with what cover size of a cover 33 one works to achieve stacking. By gearing the fold weld 34 in the radially placed conformation or by gearing in the groove 38 radially placed inside (according to 7 of the other examples). Both the groove 7 or 38, on the one hand, and the groove 32, on the other hand, are "directed outwardly." They can be provided individually or cumulatively.

The possibilities of an increase in the bottom stiffness, indicated for the reinforcement of the inner bottom area, can also be substituted by fine ribs or stretch marks or the like. The fund remains in this case still essentially flat and free of bulges which in the case of a beverage can is called "dome-shaped" bulging.

The embodiments made for the preceding embodiments to add inert gas that is under pressure for stabilization of the wall, for sheet thicknesses, for the reduced height of the essentially flat bottom, for measurements of cone-shaped sinks and for stability at the bottom pressure they can be transferred correspondingly to the examples of figures 4 and 5. These are equally valid here.

In the drawings, notch lines are not shown at the cover level of a corresponding cover 4, 24 or 33. They are familiar to the specialist and serve to open the cover, so that they are not represented in the drawing. In this case, a corresponding cover has a peripheral weakening line that can be fractured according to figures 4 or 5 with the quick-opening tongue 25 to remove the level of cover within the peripheral weakening line. This is the usual state of the art that should not be explained here separately.

Claims (20)

1.-Metal can constituted of a body of tin (1) of sheet without welds, with a trunk of tin (2) and a bottom (3; 3a; 35), essentially flat, formed in a piece with this one, the canned trunk (2) being sunk in the shape of a cone (5, 11: 31, 41) both towards the bottom (3) and towards an open end (15c); that the essentially flat bottom (3) has a groove (7) directed outwards or a groove (32), characterized in that it is configured and is suitable for housing by stacking a joint weld (12; 34) that joins one end (15c) of a second tin can of a second metal can (1a; 15) equal with a cover (4) that closes it. 2. Metal can according to claim 1, wherein the bottom groove (7) protruding axially inwardly is arranged radially inside the lower end of the sinking (5) of the trunk (2) and - preferably forming a vertical rib (6) protruding axially outward - part of the conical sinking (5) or at least is near it. 3. Metal can according to claim 1, wherein the sinking (32) is provided in the sinking area (31) in the form of a cone (conical) of the trunk (30) radially out of a vertical rib (36) which protrudes axially outward and directly borders on sinking. 4. Metal can according to one of the preceding claims, wherein the bottom (3), essentially flat, is free of concave or convex curved bottom sections. 5.-Metal can according to one of claims 1 to 4, wherein the essentially flat bottom (3) is made of several essentially flat bottom surface sections (8, 9, 10) radially offset with respect to others. 6. Metal can according to one of the preceding claims, wherein the flat bottom (3; 3a; 35) extends over a range of heights that is defined by an axially superior end of the groove (7) and an axially end lower of a vertical rib (6), in particular in a range of heights less than 5 mm. 7. Metal can according to claim 5, wherein the bottom surface sections are connected to each other respectively through narrow projections (9a, 10a) or other steps, in particular the "narrow projections" are shorter than one lateral extension of a section of respectively adjacent bottom surface, which represents a slight stepping. 8. Metal can according to claim 5, wherein the bottom (3; 3a; 35) does not protrude axially inwards more than 5 mm, measured from a lower axial end of a vertical rib (6, 36). 9. Metal can according to claim 5, wherein the bottom surface sections (8, 9, 10) are offset from each other in the axial direction through the projections (9a, 10a), preferably in a axially inward direction when viewed from the radially outer side to the radially inner side. 10. Metal can according to one of claims 1 to 9, wherein the essentially flat bottom (21) has out-of-center (22; 8) undulations (23) that run annularly 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, coverage level) is lowered with respect to the joint weld (12) and connects directly with this weld through a groove of damping (13) protruding axially inwards. 12. Metal can according to the preceding claim, in which the descent with respect to the joint weld is light, in height less than an axial height of a double fold (12). 13. Metal can according to claim 1 or 6, wherein the cover (4; 24) is configured as a cover for rapid opening with a peripheral weakening line and a tongue for rapid opening (25), and the first and the Second metal can are stacked on top of each other, the joint weld (12; 34) that joins the cover for quick opening with the second metal can being stacked. 14. Metal can according to claim 1, wherein the sinking (5) in the form of a cone has an angle between 10 ° and 30 ° with respect to the bottom (3). 15.-Metal can according to claim 1 or 4, wherein the sinking (11, 41) in the form of a cone is in the range of 30 ° ± 20% towards the open end (47). 16.-Metal can according to claim 1 or 6, wherein the essentially flat bottom has a resistance to pressure against the formation of a protuberance or against a bulge, which reaches essentially 2 bar (0.20 MPa) , as a differential pressure with respect to an outer face. 17.-Metal can according to claim 16, wherein the essentially flat bottom plate has a thickness between 0.2 mm and 0.25 mm. 18.-Metal can according to one of the preceding claims, wherein the volume of housing of the can is between 150 ml to essentially 500 ml. 19.-Metal can according to claim 16, wherein the pressure resistance reaches essentially 0.35 MPa. 20.-Procedure for the manufacture of a metal can constituted of a tin body (1) of sheet without welds, with a tin trunk (2) and a bottom (3; 3a; 35) essentially flat, formed in one piece with this, -in which the can trunk (2) sinks respectively in the form of a cone (5, 11: 31, 41) both towards the bottom and towards its open end (17); and the essentially flat bottom contains a groove (7) or groove (32) directed outwards, the groove (7) or groove (32) being adapted to accommodate a weld 5 junction (12; 34) located below, - weld joining an axial end (17) of a tin can of a second metal can (1, 30) identical with its cover (4, 33), - and Two cans can be stacked. 21.-Procedure for stacking several metal cans consisting of a can body (1) 10 of sheet without welds, with a tin trunk (2) and a bottom (3; 3a; 35) essentially flat, formed in a piece with it, in which the trunk (2) is sunk respectively in the form of a cone ( 5, 11: 31, 41) both towards the bottom (3) and towards its open end (17) and the essentially flat bottom has a groove (7) or groove (32) directed towards the outside, housing the groove (7 ) or 15 groove (32) a joint weld (12; 34) located below, - weld that joins an axial end (17) of a tin can of a second metal can (1, 30) identical with its cover (4, 33), -and the two cans are stacked.