EP0725009B1 - Method for making a metallic package having a general prismatic form and package made by this method - Google Patents

Description

The present invention relates on the one hand to a method of manufacturing a shaped metal package general prismatic and secondly a metallic packaging obtained by this process.

We already know in the state of the art, in particular according to EP-A-0 448 436, a method of manufacture of metallic packaging of general shape prismatic, of the type in which we form a body tubular metallic cross section substantially polygonal delimiting lateral faces of the package connected together by rounded corners.

• en cisaillant un flan de tôle,
• en roulant ce flan de manière à former un cylindre,
• en soudant les bords de jonction longitudinaux du cylindre, notamment à l'aide de moyens de soudage électriques, de manière à obtenir une virole métallique, et
• en imprimant à cette virole une section transversale sensiblement polygonale, (à coins arrondis), par exemple rectangulaire, à l'aide de moyens d'expansion.

Such a tubular body is obtained in a manner known per se, for example:

• by shearing a sheet metal blank,
• by rolling this blank so as to form a cylinder,
• by welding the longitudinal joining edges of the cylinder, in particular using electric welding means, so as to obtain a metallic ferrule, and
• by printing on this ferrule a substantially polygonal cross section (with rounded corners), for example rectangular, using expansion means.

It is also known to form on one end of the tubular body a fallen edge so as to ability to crimp an attached metal face on this edge forming a top or bottom of the package.

However, the rounded parts of the fallen edge thus formed, corresponding to the rounded corners of the body, have a metal deficit compared to the parts straight from the fallen edge.

Despite this metal deficit, the added face can be crimped on the dropped edge relatively satisfactory.

It would not be the same if we wished crimp the attached side on a necking formed on the end of the polygonal tubular body. Indeed, in this case the rounded portions of the necked, corresponding at the rounded corners of the body, have an excess of metal by relation to the rectilinear parts of this constriction.

The formation of a fallen edge extending the necking causes the accumulation of defects related to shrinking (excess of metal in the rounded corners) and at the fallen edge (metal deficit in the rounded corners).

The two types of faults cannot be offset between them since the excess metal due to shrinking is proportionally much larger than the deficit of metal due to the fallen edge.

Therefore, a fallen edge formed on a neck formed on the end of a tubular section body substantially polygonal cross-section has a very irregular unsuitable for crimping a face attached to the edge fallen.

US-A-3,953,994 describes a process for manufacturing a metallic packaging of generally prismatic shape during from which we form a ferrule then we cause a stretching radial (expansion) of this shell except at the level of ends of this shell. The latter thus form necks radially set back from the rest of the shell.

The object of the invention is to remedy the defects which occur present during the formation of an edge fallen on a shrinking formed on a tubular body of cross section substantially polygonal.

• on forme, à proximité d'une première extrémité du corps et sur chacun des coins de ce corps, un bourrelet d'expansion du métal faisant saillie radialement, les bourrelets provoquant sur le contour de cette première extrémité des enfoncements axiaux au niveau des coins et étant tous sensiblement à la même distance de cette première extrémité,
• on forme sur la première extrémité du corps un rétreint et un bord tombé prolongeant ce rétreint les enfoncements axiaux créant des déficits de métal permettant de compenser ultérieurement l'excès de métal apparaissant au niveau des coins arrondis du corps lorsque l'on forme le rétreint avant de former le bord tombé supérieur, et
• on sertit sur le bord tombé une face métallique rapportée formant un fond ou un dessus de l'emballage. Suivant d'autres caractéristiques de ce procédé:
• les bourrelets sont formés de manière à s'étendre radialement vers l'extérieur du corps ;
• le rétreint est formé de manière à être relié au reste du corps par une partie de liaison inclinée espacée axialement des bourrelets d'une distance comprise entre 0 et 3 mm ;
• on forme sur la seconde extrémité du corps, opposée à la première extrémité, un bord tombé et on sertit sur ce bord tombé une autre face métallique rapportée formant un dessus ou un fond de l'emballage.

To this end, the subject of the invention is a method of manufacturing a metallic packaging, of the type described in EP-A-0 448 436, characterized in that:

• there is formed, near a first end of the body and on each of the corners of this body, a metal expansion bead projecting radially, the beads causing on the contour of this first end axial depressions at the corners and all being substantially the same distance from this first end,
• forming on the first end of the body a constriction and a fallen edge extending this constriction of the axial depressions creating metal deficits making it possible to subsequently compensate for the excess of metal appearing at the rounded corners of the body when the front constriction is formed to form the upper fallen edge, and
• an added metal face is crimped onto the fallen edge forming a bottom or top of the package. According to other characteristics of this process:
• the beads are formed so as to extend radially outward from the body;
• the constriction is formed so as to be connected to the rest of the body by an inclined connecting part axially spaced from the beads of a distance between 0 and 3 mm;
• a dropped edge is formed on the second end of the body, opposite the first end, and another added metallic face is crimped onto this fallen edge forming a top or bottom of the package.

The invention also relates to packaging metallic in general prismatic shape of the type described in US A 3,953,994, comprising a tubular metal body of substantially polygonal cross section delimiting side faces of the packaging connected together by rounded corners, and one side forming the top or bottom of the package crimped on a collar formed on one end of the body, characterized in that the neck is constricted, and in that the packaging also includes a metal expansion bead projecting radially, formed on each of the corners of the body, the beads being all at the same distance from the constricted.

• les bourrelets s'étendent radialement vers l'extérieur du corps ;
• le rétreint est relié au reste du corps par une partie de liaison inclinée espacée axialement des bourrelets d'une distance comprise entre 0 et 3 mm.

According to other characteristics of this packaging:

• the beads extend radially outward from the body;
• the constriction is connected to the rest of the body by an inclined connecting part axially spaced from the beads of a distance between 0 and 3 mm.

• la figure 1 est une vue en perspective d'un corps métallique tubulaire de section transversale sensiblement rectangulaire destiné à la fabrication selon l'invention d'un emballage métallique de forme générale prismatique ;
• la figure 2 est une vue similaire à la figure 1, dans laquelle le corps tubulaire comporte de plus un bord tombé inférieur ;
• la figure 3 est une vue similaire à la figure 1, dans laquelle le corps tubulaire comporte de plus des bourrelets d'expansion du métal disposés aux quatre coins du corps ;
• la figure 4 est une vue de détail en coupe suivant un plan diamétral du corps représentant un bourrelet d'expansion ;
• la figure 5 est une vue de dessus de la figure 4 ;
• la figure 6 est une vue partielle en coupe suivant la ligne 6-6 de la figure 3 ;
• la figure 7 est une vue similaire à la figure 6 montrant une variante de réalisation du corps tubulaire;
• la figure 8 est une vue en perspective d'un emballage selon l'invention.

The invention will be better understood on reading the description which follows given solely by way of example for the understanding of which reference will be made to the appended drawings in which:

• Figure 1 is a perspective view of a tubular metal body of substantially rectangular cross section intended for the manufacture according to the invention of a metal package of generally prismatic shape;
• Figure 2 is a view similar to Figure 1, in which the tubular body further comprises a lower fallen edge;
• Figure 3 is a view similar to Figure 1, wherein the tubular body further comprises metal expansion beads disposed at the four corners of the body;
• Figure 4 is a detail view in section along a diametrical plane of the body showing an expansion bead;
• Figure 5 is a top view of Figure 4;
• Figure 6 is a partial sectional view along line 6-6 of Figure 3;
• Figure 7 is a view similar to Figure 6 showing an alternative embodiment of the tubular body;
• Figure 8 is a perspective view of a package according to the invention.

To make a shaped metal package general prismatic according to the invention, we manufacture everything first a tubular metal body 10 as shown in figure 1.

The body 10 has a cross section substantially rectangular and is intended to delimit faces 12 of the metal packaging. The side faces 12 are interconnected by rounded corners 14.

The tubular body 10 is manufactured so known per se from a sheet metal blank, which is rolled, then welded to form a ferrule and finally expanded so as to obtain a cross section substantially rectangular.

Conventionally, the lower end of the body 10 is closed by forming a lower fallen edge 16 on this lower end and then crimping on this edge 16 an attached metal face (not shown) in the figures) forming the bottom of the packaging.

The bottom is set on the lower dropped edge either just after this fallen edge is formed or later.

Furthermore, as shown in the Figures 3 to 5, we form, near the end upper body 10 and on each of the corners 14 of this body, a bead 18 projecting radially towards outside the body, relative to the longitudinal direction of this body.

Alternatively, the beads 18 can extend radially inward of the body.

Note that the beads 18 are all substantially at the same distance from the upper end of the body and have for their plane of symmetry the diametrical planes body 10.

The beads 18 are formed using means known to extend parallel to a plane transverse of the body 10 substantially along the same angular sector as the corresponding rounded corners.

Due to the expansion of the metal resulting from the formation of the beads 18, the contour of the end upper part of the body 10 present, at this manufacturing stage packaging, axial depressions at the level corners 14. These depressions are indicated by vertical arrows in Figure 3. An axial depression E is shown in more detail in FIG. 4.

After having formed the beads 18, we form on the upper end of the body 10 a constriction 20 and a upper fallen edge 22 extending this constriction, using known means, as shown in the figure 6.

The neck 20 is connected to the rest of the body 10 by an inclined connection part 20L. This 20L part is axially spaced from the beads 18 by a distance D preferably between 0 and 3 mm.

In the example shown in Figure 6, the distance D is not zero, while in the variant shown in Figure 7, the distance D is zero if although the inclined connecting part 20L extends directly the beads 18.

The axial depressions E create deficits of metal to subsequently compensate for excess metal appearing at the rounded corners of the body 10 when forming the neck 20 before forming the upper drop edge 22. The size of the beads may be easily determined based on the excess of metal to be compensated for when forming shrinking followed by the upper fallen edge.

The contour of the fallen edge 22 thus obtained is regular, that is to say that its dimension following a radial direction relative to the body 10 is substantially identical both in the rounded parts and in the straight parts of the fallen edge.

Finally, in order to close the upper end of the body 10, it is crimped in a manner known per se on the edge dropped above 22 an attached metal face 24 intended to form the top of the package. We obtain thus a package 26 as shown in FIG. 8.

The contour of the upper fallen edge 22 being regular, the crimp top can be easily positioned on the fallen edge and the setting obtained thereafter is of very good quality.

The metallic packaging obtained according to the process of the invention described above are easily stackable on top of each other. Indeed, the end bottom of a package is nestable on the end upper shrinkage from other similar packaging.

The invention is not limited to the examples of realization described above.

In particular, the tubular body can have a any substantially polygonal cross section, other than rectangular.

Furthermore, the necking can be formed either on the upper or lower end of packaging.

Claims (7)

1. Process for manufacturing a metal container of generally prismatic shape of the kind in which there is formed a tubular metallic body (10) of substantially polygonal cross-section defining side faces 12 of the container connected together by rounded corners (14), characterised in that:

   there is formed near a first end of the body 10 and at each of the corners (14) of this body an expansion bead (18) of metal projecting radially, the beads (18) producing on the profile of this first end axial depressions (E) at the level of the corners (14) and all being at the same distance from this first end,

   there is formed on the first end of the body (10) a set-in portion (20) and a flanged rim (22) forming a continuation of this set-in portion (20), the axial depressions (E) creating deficits of metal which subsequently allow compensation for the excess of metal appearing at the level of the rounded corners of the body (10) when the set-in portion (20) is formed and before the formation of the upper flanged rim (22), and

   there is secured to the flanged rim (22) an associated metal disc (24) forming a base or a lid of the container.
2. Process according to claim 1, characterised in that the beads (18) are formed in such a way as to extend radially towards the outside of the body (10).
3. Process according to claim 1 or 2, characterised in that the set-in portion (20) is formed in such a way as to be connected to the remainder of the body (10) by an inclined connecting portion (20L) spaced axially from the beads (18) by a distance (D) of between 0 and 3 mm.
4. Process according to any one of the foregoing claims, characterised in that there is formed on the second end of the body (10) opposite the first end a flanged rim (16) and there is joined onto this flanged rim (16) another associated metal disc forming a lid or a base of the container.
5. Metal container of generally prismatic shape of the kind comprising a tubular metallic body (10) of substantially polygonal cross-section defining side faces (12) of the container joined to one another by rounded corners (14) and a disc (24) forming a lid or base of the container and joined to a neck (20) provided on an end of the body (10), characterised in that the neck is a set-in portion (20) and in that the container has an expansion bead (18) of metal which projects radially and is provided at each of the corners (14) of the body (10), the beads (18) all being at the same distance from the set-in portion (20).
6. Container according to claim 5, characterised in that the beads (18) extend radially towards the outside of the body (10).
7. Container according to claim 5 or 6, characterised in that the set-in portion (20) is joined to the remainder of the body (10) by an inclined connecting portion (20L) spaced axially from the beads (18) by a distance (D) of between 0 and 3 mm.

Images