WO2016146362A1

WO2016146362A1 - Can body

Info

Publication number: WO2016146362A1
Application number: PCT/EP2016/053995
Authority: WO
Inventors: Ralf WERSUHN; Willem Leendert Pieter Van Dam; Norbert Mertens; Alexander Kolb
Original assignee: Ball Europe Gmbh
Priority date: 2015-03-13
Filing date: 2016-02-25
Publication date: 2016-09-22
Also published as: BR112017019318A2; WO2016146362A9; DE102015204654A1; CA2979582A1; EP3268287A1; AU2016232576A1; CN107735331A

Abstract

The invention relates to a can body for a beverage can. The can body is formed in one piece from sheet metal and comprises a circumferential wall as a side wall and a can bottom which has a calotte-shaped central section which is curved inwards and a standing section which surrounds the central section in an annular manner and curves outwards. The standing section curved outward is connected to the circumferential wall by means of an outer transition section extending aslant in the cross-section and defines a standing ring, along which the standing section at least approximately touches a flat surface when the can body is placed on such a flat surface. The geometry of the bottom is defined by three partial radii R3a, R3b and R3c, which describe the geometry of a standing ring as part of the standing section curved outwards and have the following dimensions: 0.8 < R3a < 1.2 mm, 1.2 < R3b < 1.6 mm, and 2.0 < R3a < 3.0 mm.

Description

can body

The invention relates to a one-piece can body in particular for beverage cans.

Known are so-called two-piece beverage cans, which consist of a can body and a lid, can body and lid are typically sealed together by a double fold. The lid itself can in turn be multi-part and typically has at least one grip tab or a resealable closure.

The can body itself is one-piece and formed from an originally flat aluminum or steel sheet. The methods and tools for forming a can body from sheet metal by means of stretch forming are known in principle. It is also known that typical can bodies for beverage cans have an inwardly curved bottom to impart pressure resistance to the bottom. In the area of the (before filling) open end of the can body, the can body is typically provided with a tapered "neck", so slightly retracted.

The geometry of the bottom section is chosen such that the can filled, for example, with carbonated drinks, can withstand a high internal pressure of the order of magnitude can withstand 6 bar, without the floor extends beyond a tolerable extent to the outside. The latter is referred to as "soil growth" and is the result of soil deformation due to internal pressure in the can The goal in the design of a can body is typically to achieve a sufficiently high strength with as little material and manufacturing effort as possible.

This object is also based on the present invention.

According to the invention, a can body is proposed for a beverage can, wherein the can body is integrally formed from sheet metal and has a peripheral wall as a side wall and a can bottom, which has a dome-like inwardly curved central portion and a central portion annularly surrounding and outwardly curved stand portion. The outwardly curved stand portion is connected via a cross-sectionally inclined outer transition portion with the peripheral wall and defines a stand ring along which the stand portion at least approximately contacts a flat surface when the can body is placed on such a flat surface.

The geometry of the floor is defined by at least a first radius R1, which describes the curvature of the inwardly curved central portion, at least a second radius R2, which describes the geometry of a transition from the inwardly curved central portion to the standing portion, at least one third radius R3, which describes the geometry of a stationary ring as part of the outwardly arched stand section, and defines at least one fourth radius R4, which describes the geometry of an inwardly curved peripheral bead on the outside of the stand section. According to the invention, the geometry of the stationary ring is defined by three partial radii R3a, R3b and R3c, which have the following dimensions: 0.8 <R3a <1 .2mm

1.2 <R3b <1.6mm 2.0 <R3a <3.0mm

Between the second radius R2 and the partial radius R3a, there is provided a sectional view of a grader section IL which extends from the second radius R2 to the partial radius R3a and defines a frusto-conical portion of the floor.

The partial radii R3a, R3b and R3c are preferably in an approximate ratio of 3: 4: 9 (R3a: R3b: R3c).

The ground geometry according to the invention is based on the finding that cans which are specifically or indirectly induced by the standard soil-forming process - either pneumatically, hydraulically or mechanically - induce soil growth or have a lower deformation or soil growth potential. However, such a pre-deformation is not feasible with reasonable effort. The geometry according to the invention can be produced in a conventional manner and offers a similarly low soil growth, such as pre-formed can bodies. This improvement is not achieved by changing the manufacturing process, but by redesigning the tools.

The sheet metal of the can body is preferably sheet steel. Alternatively, the sheet is aluminum sheet.

If the sheet metal of the can body is sheet steel, this preferably has a maximum sheet thickness of less than 0.205 mm, preferably less than 0.200 mm, in the region of the dome-like inwardly curved central portion.

The inwardly curved central portion is preferably completely concave from the outside and forms a dome, which extends to the stand section.

The outer diameter of the side wall is preferably between 51 mm and 68 mm, for example about 53 or 58 mm or 66 mm. Preferred diameters are 51mm to 55mm, 56mm to 60mm and 64mm to 68mm. Preferably, the geometry of the floor is additionally defined by at least one fifth radius R5, which describes the geometry of a transition from the stand section to the side wall and is between 2.5 mm and 7.5 mm.

The geometry of the dome-like inwardly curved central portion is preferably defined by two first partial radii R1a and R1b, of which the partial radius R1a is between 30 mm and 55 mm and the partial radius Rb is between 15 mm and 55 mm.

The second radius R2 is preferably between 1.5 mm and 3 mm. The fourth radius R4 is preferably between 2 mm and 5 mm. A tangent to the second radius R2 and the partial radius R3a at the transition from the second radius R2 to the partial radius R3a is preferably inclined inwardly at an angle alpha relative to the longitudinal axis of the can body. The angle alpha is preferably between 3 ° and 15 °. Between the second radius R2 and the partial radius R3a, the geometry of the bottom has a section IL which is straight in the sectional view and extends from the second radius R2 to the partial radius R3a and preferably has a length of between 1.7 mm and 2.5 mm , for example, 2, 1 mm. The straight section IL is inclined by the angle alpha 1, ie preferably between 3 ° and 15 °, relative to the longitudinal axis of the can body inwards (starting from the contact plane). The grade section IL thus describes a truncated cone with a cone angle (as the opening angle of the associated cone) between 6 ° and 30 °.

A tangent to the partial radius R3c and the radius R4 at the transition from the partial radius R3c to the radius R4 is preferably inclined at an angle alpha2 with respect to the longitudinal axis of the can body to the outside. The angle alpha2 is preferably between 10 ° and 40 °, in particular between 15 ° and 30 °, for example about 19 °.

A tangent to the fourth radius R4 and the fifth radius R5 at the transition from the fourth radius R4 to the fifth radius R5 is preferably upwardly inclined at an angle alpha3 with respect to a standing plane defined by the pedestal, wherein the angle alpha3 between 25 ° and 40 ° is. It should be noted that the base ring contacts a flat surface along a circular ridge when the can body is placed on the flat surface. The uprising line simultaneously defines a rearing plane that is perpendicular to the central longitudinal axis of the can body. Preferably, the partial radius R3b extends over an angle alpha R3b, which is between 10 ° and 60 °, in particular between 25 ° and 45 °, and in particular about 36 °.

Preferably, the partial radius R3a ends at the contact line and goes there continuously differentiable (ie without kink and thus smooth) in the partial radius R3b on. A tangent to the partial radius R3a and the partial radius R3b at the transition from the partial radius R3a to the partial radius R3b thus runs in the contact plane defined by the contact line.

Furthermore, it is preferred if the centers of the partial radii R3a and R3b are at least approximately on a perpendicular to the contact plane extending through the contact line.

The finished (final) geometry of the floor is produced solely by deep drawing without subsequent reforming, as can be seen on the straight section IL and thus differs from a geometry as described for example in DE 10 2013 226 032 A1. The aforementioned object is preferably also achieved by a can, in particular a beverage can, which has a can body of the type described above, and also a lid which is connected via a double fold with the can body. The lid has a central ceiling mirror with a tear field disposed therein. On the lid, and in particular the lid mirror, a tear-open tab for breaking the tear field, for example, a so-called stay-on tab, attached. Such a can has a very low soil growth on the order of less than 1 mm even at a high internal pressure of the order of 6 bar. The can preferably has a nominal volume of 330 ml. Accordingly, the can body is also sized so that it leads to a can with a filling volume of 330 ml. The invention will now be explained with reference to an embodiment with reference to the figures. From the figures shows:

Fig. 1: An overall perspective view of a beverage can with a can body according to the invention; 2 shows a side view of a can body according to the invention for a

Beverage can with a filling volume of 330 ml;

3 shows a side view of a can body for a beverage can with a

Filling volume of 355 ml;

4 shows a detail of the bottom geometry of the can bodies of FIGS. 2 and 3;

and

Fig. 5: the detail of Figure 4 in another representation.

The beverage can 10 shown in FIG. 1 has a can body 12 and a cover 16 connected to the can body 12 via a double fold 14; The lid has a central lid mirror 18 in the usual manner, in which a tear-open panel 20 is arranged and to which a tear-open tab 22 is fastened, with which the tear-open panel 20 can be opened. The tear tab 22 (also called opener tab) may be, for example, a so-called stay-on tab, which remains connected to the lid 16 even after the tear-open panel 20 has been opened.

Figures 2 and 3 show side views of the can body 12 before closing with a lid 16. The can body 12 is integrally formed from an originally flat aluminum or steel sheet and has a peripheral wall 24 as a side wall and a can bottom 30, the dome-like inwardly curved central portion 32 and a central portion surrounding the ring and outwardly curved stand portion 34 has. The outwardly curved stand portion is connected via a cross-section obliquely outwardly extending outer transition portion 36 with the peripheral wall 24 and defines a stationary ring 38, along which the stationary ring at least approximately touches a flat surface when the can body is placed on such a flat surface. The line along which the base ring contacts the flat surface is also referred to as a riot line in the context of this description and is circular. The riot line defines a riot plane perpendicular to a central longitudinal axis of the can body 12 extends. The dome-like inwardly curved central portion 32 has at its center the greatest distance from the contact plane. This distance, which is referred to as the bottom depth DD, is preferably between 8mm and 12mm. The diameter of the base ring, more specifically the diameter DS of the circular ridge line is preferably between 40mm and 48mm.

The geometry of the floor (bottom geometry) is shown in Fig. 4 in detail. The dome-like inwardly curved central portion 32 of the bottom 30 has a geometry which is defined by at least a first radius R1. In the exemplary embodiment, the geometry of the dome-like inwardly curved central portion 32 of the bottom 30 by two partial radii R1 a and R1 b defined, of which the first partial radius R1 a is about 48 mm and the other first partial radius R1 b is about 41 mm.

The dome-like inwardly curved central portion 32 merges into the stand portion 34 in a second radius R2. The second radius R2 is about 2 mm in the embodiment.

The second radius R2 is adjoined by the stationary ring 38 whose geometry is defined by at least one third radius R3. In the exemplary embodiment and according to the invention, the geometry of the stationary ring 38 is defined by three partial radii R3a, R3b and R3c. The partial radius R3a in the exemplary embodiment is about 1.1 mm, the partial radius R3b in the exemplary embodiment is about 1.4 mm, and the partial radius R3c in the exemplary embodiment is about 2.5 mm.

The skirt 38 is followed by an inwardly curved, circumferential bead whose geometry is defined by a fourth radius R4, which in the exemplary embodiment is approximately 2.8 mm. Finally, the stand section 34 merges into the side wall 24 of the can body 12 in a fifth radius R5. The fifth radius R5 is about 5 mm.

In addition, the bottom geometry is also defined by the fact that the second radius R2 smoothly merges into the partial radius R3a and that there is a tangent at this transition to the second radius R2 and the partial radius R3a, which at an angle of about 6 ° relative to the central Longitudinal axis of the can body 12 is inclined inwards. Between the second radius R2 and the partial radius R3a, the bottom geometry has a section IL, which is sectioned in the sectional view, extending from the second radius R2 to the second Partial radius R3a extends and preferably has a length between 1, 9 mm and 2.3 mm. In the illustrated embodiment, the length of the straight section IL 2, 1 mm. The straight section IL is inclined inwards by the angle alpha 1, that is to say by about 6 °, relative to the longitudinal axis of the can body, starting from the uprising plane. The grade section IL thus describes a truncated cone with a cone angle (as the opening angle of the associated cone) of about 12 ° and a height of about 2, 1 mm.

The base ring 38 is also smooth in the inwardly curved, circumferential bead over. At this transition, the partial radius R3c changes into the fourth radius R4. The tangent to these two radii is inclined relative to the central longitudinal axis of the can body 12 by about 19 ° to the outside.

The fourth radius R4 smoothly merges into the fifth radius R5. At this transition there is a tangent to the two radii R4 and R5, which is inclined upwards by about 32 ° with respect to the contact plane. In addition, the geometry of the base ring 38 is also defined by the fact that the radius R3b extends over an angle of about 36 °. This angle begins at the riot line and extends outward. At the contact line, partial radius R3a smoothly merges into partial radius R3b. A tangent at this transition runs in the contact plane and thus at right angles to the central longitudinal axis of the can body 12. Such a bottom geometry provides a beverage can with a diameter of preferably about 58 mm when using thin sheet thicknesses with sheet thicknesses of about 0.205mm, 0.200mm and smaller, especially 0.195mm and 0.190mm such a strength in the soil area that even at a high internal pressure to a soil growth of less than 1 mm comes.

LIST OF REFERENCES

10 soda can

12 can bodies

14 double fold

16 lids

18 central lid mirror

20 tear field

22 pull-tab

24 side wall

30 bottom of the can

32 central section

34 stand section

36 transition section

38 Stand ring

Claims

claims

1. One-piece can body for a beverage can with an opening, a side wall and a bottom, which adjoins the side wall and a dome-like inwardly curved central portion and an outwardly curved, adjoining the inwardly curved central portion and this annularly surrounding stand portion to which the side wall adjoins, the can body having a central longitudinal axis and the geometry of the bottom by at least a first radius R1 describing the curvature of the inwardly curved central portion, at least one second radius R2 having the geometry of a transition from the inwardly arched central portion to the stand portion, at least a third radius R3, which describes the geometry of a stationary ring as part of the outwardly curved stand portion, and at least a fourth radius R4, the geometry of an inwardly curved circumferential bead a describes on the outside of the stand section, is defined, characterized in that the geometry of the stationary ring is defined by three partial radii R3a, R3b and R3c, which have the following dimensions:

0.8 <R3a <1 .2mm

1.2 <R3b <1 .6mm

2.0 <R3a <3.0mm wherein between the second radius R2 and the partial radius R3a is provided a sectional view of the grader section IL extending from the second radius R2 to the partial radius R3a and defining a frusto-conical portion of the floor. A can body according to claim 1, characterized in that the partial radii R3a, R3b and R3c are in an approximate ratio of 3: 4: 9 (R3a: R3b: R3c).

Can body according to claim 1 or 2, characterized in that the side wall has a diameter between 51 mm and 68mm.

Can body according to at least one of claims 1 to 3, characterized in that the sheet metal of the can body is steel sheet.

Can body according to at least one of claims 1 to 4, characterized in that the sheet metal of the can body in the region of the dome-like inwardly curved central portion has a maximum sheet thickness of less than 0.205 mm, preferably less than 0.200 mm.

Can body according to at least one of claims 1 to 5, characterized in that the geometry of the bottom is defined by at least a fifth radius R5, which describes the geometry of a transition from the stand section to the side wall and is between 2.5 mm and 7.5 mm.

Can body according to at least one of claims 1 to 6, characterized in that the geometry of the dome-like inwardly curved central portion by two first partial radii R1 a and R1 b is defined, applies to the applies

30 <R1a <55mm

15 <R1b <55mm

Can body according to at least one of claims 1 to 7, characterized in that the second radius R2 is between 1.5mm and 3mm.

Can body according to at least one of claims 1 to 8, characterized in that the fourth radius R4 is between 2mm and 5mm.

A can body according to at least one of claims 1 to 9, characterized in that the sectional section IL in the sectional view is at an angle alphal is inclined inwardly relative to the longitudinal axis of the can body, wherein the angle alpha is between 3 ° and 15 °.

Can body according to at least one of claims 1 to 10, characterized in that a tangent to the partial radius R3c and the radius R4 is inclined at the transition from the partial radius R3c to the radius R4 at an angle alpha2 relative to the longitudinal axis of the can body to the outside, said Angle alpha2 between 10 ° and 40 °, preferably between 15 ° and 30 ° and particularly preferably about 19 °.

Can body according to claim 6 and at least one of claims 1 to 5 and 7 to 1 1, characterized in that a tangent to the fourth radius R4 and the fifth radius R5 at the transition from the fourth radius R4 to the fifth radius R5 at an angle alpha3 is inclined upwards with respect to a standing plane defined by the collar, wherein the angle alpha3 is between 25 ° and 40 °.

Can body according to at least one of claims 1 to 12, characterized in that the partial radius R3b extends over an angle alpha R3b, which is between 10 ° and 60 °, preferably between 25 ° and 45 °, and particularly preferably about 36 °.

Can body according to at least one of claims 1 to 13, characterized in that the stand ring defines a circular ridge along which the base ring touches a riot plane when the can body is parked on a plane extending in the riot plane surface, wherein the partial radius R3a at the contact line ends and there rises differentiable in the partial radius R3b passes.

The can body according to claim 14, characterized in that the centers of the partial radii R3a and R3b are at least approximately on a vertical line extending through the contact line to the contact surface.

16. can body according to at least one of claims 1 to 15, characterized in that the straight section IL has a length between 1, 7mm and 2.5 mm.

17. Cans having a can body according to at least one of claims 1 to 16 and a lid connected to the can body by a double fold having a lid mirror a tear field and a pull tab attached to the lid.