EP0577503B1 - Method of making a can consisting of a metallic body and lid and can made by this process - Google Patents

Abstract

This can includes a body (34) and a lid (22) made in the same metal. This method includes the following steps: A) a metal blank is deep drawn in order to form a hollow element which includes a skirt (4), a shoulder facing towards the inside of the skirt, and a side wall of smaller cross-section extending the skirt from the shoulder and closed against the latter; B) the hollow element is separated, by cutting, into two elements, a first element including the tubular wall and the end wall (12) which closes it, and the second element including the skirt (4) and at least part of the shoulder; C) the first element is converted, by forming, into the lid (22), and the second element into the can body (34) suited to receiving it; D) the lid (22) and the body (34) of the can are rigidly fixed to each other by means of a heat-sealed or adhesively-bonded flat annular bead (36). <IMAGE>

Description

The present invention relates to a method of manufacturing a box consisting of a body and a cover made of the same metal according to the preamble of claim 1 and a box according to the preamble of claim 9.

The box body has a bottom and an opposite open end delimited by a flange cooperating with a peripheral part of the cover to close the box.

The cover may be of the type commonly known as "styling", that is to say bearing on the outer face of the rim, or of the type commonly known as "plug", that is to say comprising a side wall received in the opening.

Generally, such boxes further include, when closed, a metal tape soldered with tin on the body and the cover to make the latter secured to the body.

In such a case, the tape which constitutes a safety device making it possible to ensure that the box has never been opened must be separated from the body and the cover when the box is first opened.

The manufacture of such a box has hitherto been obtained by rolling and welding a metal strip to form a cylindrical tube. The end of the tube intended to receive the cover is then deformed axially, so as to define two parts of different diameters and the tube is also provided with a bottom.

A first part, the diameter of which is the smallest, defines the opening of the box body and its end cooperates with a groove in the cover provided with a seal for closing the box.

The cover has a generally cylindrical peripheral wall of the same diameter as the second part, so that a cylindrical strip can then be welded to the second part and the wall. cover device to constitute a safety and opening device.

A box produced according to the method described above is relatively expensive and unattractive, because it has a weld necessary for producing the tube and requires a high number of operations.

In addition, the metallic cylindrical strip is welded by means of a tin alloy containing a little lead. Legislation tends to prohibit the use of lead in the food sector.

To overcome these drawbacks, the purpose of the present invention is to provide a method of manufacturing a metal can, the body of which does not have a tin solder, neither for the attachment of the cover nor to the body, the can being easily opened without using any particular utensil, the cover of the box being able to be repositioned after opening and the production of the box being simple and of a reduced cost.

• A) on emboutit un flan métallique pour former un élément creux comportant une jupe, un épaulement dirigé vers l'intérieur de la jupe, et une paroi latérale de plus petite section prolongeant la jupe à partir de l'épaulement et fermée à l'opposé de ce dernier,
• B) on sépare par découpe l'élément creux en deux éléments, un premier élément comportant la paroi tubulaire et la paroi d'extrémité qui la ferme et le second élément comportant la jupe et au moins une partie de l'épaulement,
• C) on transforme par formage le premier élément en couvercle et le second élément en corps de boîte adapté pour le recevoir,
• D) on solidarise le couvercle et le corps de la boîte au moyen d'un cordon annulaire plan thermoscellé ou collé.

To this end, the subject of the present invention is a method of manufacturing a box having a body and a cover made of the same metal, characterized in that it comprises the following steps, in which:

• A) a metal blank is stamped to form a hollow element comprising a skirt, a shoulder directed towards the inside of the skirt, and a side wall of smaller section extending the skirt from the shoulder and closed opposite of the last,
• B) the hollow element is divided by cutting into two elements, a first element comprising the tubular wall and the end wall which closes it and the second element comprising the skirt and at least part of the shoulder,
• C) the first element is transformed by forming into a cover and the second element into a can body adapted to receive it,
• D) the cover and the body of the box are secured by means of a planar annular bead heat sealed or glued.

• l'étape de séparation de l'élément creux en deux éléments est réalisée par découpage de l'épaulement selon une ligne de coupe située entre la jupe et la paroi tubulaire, l'épaulement étant découpé pour former un rebord sortant solidaire du premier élément et un rebord rentrant solidaire du second élément,
• on déforme la paroi tubulaire et le rebord sortant du premier élément avec expansion vers l'extérieur de la périphérie de sa paroi d'extrémité en formant un couvercle muni d'un rebord périphérique sensiblement parallèle à cette dernière, et on forme une gorge annulaire de réception du rebord périphérique du couvercle dans la face extérieure du rebord rentrant du second élément, ce dernier étant également muni d'un fond.
• lors de l'emboutissage du flan pour former l'élément creux, on forme également une gorge annulaire sur la face extérieure de l'épaulement et la séparation de l'élément creux en deux éléments est effectuée par découpage de la paroi tubulaire selon une ligne de découpe située sensiblement dans le plan de la face extérieure de l'épaulement de manière à former un rebord rentrant, solidaire du second élément, délimitant la gorge annulaire,
• on déforme la paroi tubulaire du premier élément, avec expansion vers l'extérieur de la périphérie de la paroi d'extrémité, en formant un couvercle muni d'un rebord périphérique sensiblement parallèle à cette dernière, destiné à être reçu dans la gorge annulaire de l'épaulement, du second élément, ce dernier étant fermé par un fond,
• le cordon annulaire plan recouvre à la fois le rebord périphérique du couvercle et la face extérieure du rebord rentrant du corps de boîte,
• l'expansion de la paroi tubulaire et de la première partie d'épaulement ou de la paroi tubulaire du premier élément, est inférieure à 15% environ,
• on forme en outre des gradins dans la paroi d'extrémité.

According to other characteristics of preferred embodiments of this method:

• the step of separating the hollow element into two elements is carried out by cutting the shoulder along a cutting line located between the skirt and the tubular wall, the shoulder being cut to form an outgoing rim secured to the first element and a re-entrant flange secured to the second element,
• the tubular wall and the flange exiting the first element are deformed with expansion towards the outside of the periphery of its end wall by forming a cover provided with a peripheral flange substantially parallel to the latter, and an annular groove of reception of the peripheral rim of the cover in the external face of the re-entrant rim of the second element, the latter being also provided with a bottom.
• during the stamping of the blank to form the hollow element, an annular groove is also formed on the external face of the shoulder and the separation of the hollow element into two elements is carried out by cutting the tubular wall along a line cutting located substantially in the plane of the outer face of the shoulder so as to form a re-entrant rim, integral with the second element, delimiting the annular groove,
• the tubular wall of the first element is deformed, with expansion towards the outside of the periphery of the end wall, by forming a cover provided with a peripheral rim substantially parallel to the latter, intended to be received in the annular groove of the shoulder, of the second element, the latter being closed by a bottom,
• the flat annular bead covers both the peripheral rim of the cover and the external face of the re-entrant rim of the box body,
• the expansion of the tubular wall and of the first shoulder part or of the tubular wall of the first element is less than approximately 15%,
• steps are also formed in the end wall.

The invention also relates to a box comprising a body, a bottom and a cover, characterized in that the body comprises a peripheral skirt and a re-entrant flange provided with an annular groove, and in that the cover is provided with a peripheral rim intended to cooperate with the re-entrant rim of the body, the box further comprising an annular bead of planar securing covering both the peripheral rim of the cover and the outer face of the re-entrant rim of the body of the box.

• le cordon est thermoscellé,
• le cordon est collé,
• le cordon est en aluminium,
• le cordon est en matière plastique,
• le cordon est en un matériau associant l'aluminium et le plastique.

According to characteristics of preferred embodiments of this box:

• the bead is heat sealed,
• the cord is glued,
• the cord is made of aluminum,
• the cord is made of plastic,
• the cord is made of a material combining aluminum and plastic.

• les Fig.1 à 6 sont des vues en coupe représentant les différents organes obtenus lors de la mise en oeuvre des étapes du procédé selon l'invention;
• les Fig.7 à 11 sont des vues analogues à celles des figures 1 à 6 d'une variante d'exécution du procédé.

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

• Fig. 1 to 6 are sectional views representing the different members obtained during the implementation of the steps of the method according to the invention;
• Figures 7 to 11 are views similar to those of Figures 1 to 6 of an alternative embodiment of the method.

To obtain, according to the invention, a cylindrical metal box and a complementary cover made of the same metal, a metal blank having a disc shape (not shown) is used.

In a first step, the blank is stamped to obtain a hollow bell-shaped element 2 of substantially constant thickness, as shown in Fig.1.

The bell 2 comprises a cylindrical skirt 4 of axis X-X having an open end comprising a crimping rim 6 radially outside.

The end of the skirt opposite the rim 6 is closed by a radially inner annular shoulder 8, from which extends a tubular side wall 10 closed by a circular end wall 12 of axis XX and offset towards the outside of the skirt relative to the shoulder 8.

The bell is then separated into two elements 16 and 20 (see FIG. 2) by cutting the shoulder 8 along a line 14 of circular cutting of axis XX located between the skirt 4 and the tubular wall 10, the line 14 being shown in broken lines in Fig. 3.

A first element 16 obtained after separation of the bell into two elements comprises the end wall 12, the tubular wall 10, and a first part 18 of shoulder, forming an outgoing rim.

The second element 20 includes a second shoulder portion 19 forming a re-entrant rim, the skirt 4, and the rim 6.

These elements 16 and 20 are deformed so as to transform the first element 16 into a cover and the second element 20, into a can body.

When the first element 16 is deformed, the tubular wall 10 and the outgoing flange 18 are deformed with radial expansion of the assembly, that is to say that the diameter of the periphery of the cover 22 obtained (see FIG. 4), is larger than the outside diameter of the first element 16.

est limité au maximum à 0,15 et de préférence à 0,10.To avoid breakage at the periphery of the cover, the radial expansion is limited depending on the metal used. The rate of radial expansion, that is to say: $$\frac{\text{cover diameter - diameter of the first element}}{\text{diameter of the first element}}$$

is limited to a maximum of 0.15 and preferably 0.10.

During this expansion, the tubular wall 10 and the protruding rim 18 of the shoulder are transformed into a connection zone comprising a fold 24 between the end wall 12 and a ring 26 of axis XX parallel to the general plane of the wall end 12.

Steps 28 are made by stamping the end wall 12 to increase its resistance when necessary.

It should be noted that the steps can be made at the end of the drawing of the blank.

When the second element 20 is deformed, the re-entrant flange 19 is deformed so as to produce an annular groove 30 in the external face of the latter (see FIG. 5).

The dimensions of the groove 30 are adapted so that the ring 26 of the cover can be received against the bottom of the groove.

These different steps being carried out, the cover 22 is placed on the second element 20, the ring 26 resting on the bottom of the groove 30.

A plane annular ring or bead 36, for example made of plastic, is then glued or heat-sealed so as to overlap the ring 26 and the zone adjacent to the inside edge 19 to form a peelable safety cordon (see Fig. 6).

The cord connecting two parts of walls located substantially in the same radial plane is easier to produce than in the prior art in which it connects two parts of side walls.

The second element 20-cover 22 assembly forms a box body 34.

The box body 34 is then filled and a bottom 32 is fixed by crimping on the crimping rim 6 of the skirt 4 of the second element (see Fig. 6).

As a variant, the bottom 32 is initially fixed by crimping on the crimping rim 6 of the skirt 4 of the second element, then the second element 20-bottom 32 assembly is filled, the cover then being, for example, heat-sealed on the rim of the second element.

It should be noted that the method according to the invention described above is adaptable for producing a styling cover or a cover of the plug type which is distinguished only by the fact that the fold 24 is different.

An alternative implementation of the method is shown in Figs. 7 to 11.

The different parts of the box have the same reference number as that used when describing the process with reference to drawings 1 to 6.

In this variant, the groove 30 is produced during the stamping of the blank (see Fig. 7) and the separation of the bell 2 is carried out by cutting the tubular wall 10 along a cutting line 14 'situated in a radial plane near the outer face of the shoulder 8.

In other words, the shoulder 8 forms a re-entrant flange 19 delimiting the groove 30 and entirely integral with the second element 20 (see FIG. 10), which avoids subsequent deformation of the shoulder 8.

It suffices to crimp the bottom 32 on the second element 20 to obtain the box body.

The first element 16 (see FIG. 8) comprises the end wall 12 and the tubular wall 10.

The tubular wall is then deformed with radial expansion, as described above, to form the periphery of the cover.

It should be noted that in the example shown, the steps 28 were also produced on the end wall 12 during the stamping of the blank, but that these can be produced after separation of the bell into two elements.

In the variant shown in Figs. 7 to 11, the cover obtained is a cover of the plug type because the fold 24 (see Fig. 9) produced during the deformation of the tubular wall, has an outer wall 40 slightly inclined by relative to the axis XX and of dimension adapted to penetrate into the opening of the box body.

The box produced according to the variant described above is provided with a flat annular bead 36, for example made of aluminum, plastic or a material combining aluminum and plastic, heat-sealed or bonded (see FIG. 11).

Although the method described above, and its variant provide a cylindrical box and a cylindrical cover, the method, or its variant, is adaptable to any form of box, or cover.

By the method according to the invention, a more economical box is obtained because the steps are easy to carry out industrially and are less costly, in particular because there is no need to make a weld having an appearance correct along the body of the box.

The absence of soldering also provides better aesthetics to the box obtained and allows a pre-printing of a decoration on the blank, this decoration being able to be continuous on the box body unlike the prior art, in which it is interrupted by welding.

Claims (14)

1. Method of making a can having a body (34) and a lid (22) made from the same metal, characterized in that it includes the following steps, in which:

   A) a metal blank is drawn to form a hollow element (2) including a skirt (4), a shoulder (8) pointing towards the inside of the skirt, and a lateral wall (10) of smaller cross section extending the skirt starting from the shoulder and which is closed at the opposite end from this shoulder,

   B) the hollow element is divided, by cutting, into two elements, a first element (16) including the tubular wall (10) and the end wall (12) which closes it and the second element (20) including the skirt (4) and at least part of the shoulder (8),

   C) forming operations are used to convert the first element (16) into a lid (22) and the second element (20) into a can body (34) designed to accommodate it,

   D) the lid (22) and the body (34) of the can are joined together using a thermally sealed or bonded flat annular bead (36).
2. Method of making a can according to Claim 1, characterized in that the step of dividing the hollow element (2) into two elements (16, 20) is carried out by cutting through the shoulder (8) along a cutting line (14) situated between the skirt (4) and the tubular wall, the shoulder being cut to form an outwardly projecting rim (18) attached to the first element (16) and an inwardly projecting rim (19) attached to the second element (20).
3. Method of making a can according to Claim 2, characterized in that the tubular wall and the outwardly projecting rim (18) of the first element are deformed with outward expansion of the periphery of its end wall thereby forming a lid (22) equipped with a peripheral rim (26) which is substantially parallel to this end wall, and an annular groove (30) for accommodating the peripheral rim of the lid is formed in the outer face of the outwardly projecting rim (19) of the second element (20), the latter also being equipped with an end face (32).
4. Method of making a can according to Claim 1, characterized in that, when the blank is being drawn to form the hollow element (2), an annular groove (30) is also formed on the outer face of the shoulder (8) and the dividing of the hollow element (2) into two elements (16, 20) is carried out by cutting through the tubular wall (10) along a cutting line (14') situated substantially in the plane of the outer face of the shoulder (8) so as to form an inwardly projecting rim (19) attached to the second element (20) and delimiting the annular groove (30).
5. Method of making a can according to Claim 4, characterized in that the tubular wall (10) of the first element is deformed with outward expansion of the periphery of the end wall (12), thereby forming a lid (22) equipped with a peripheral rim (26) substantially parallel to this end wall and intended to be accommodated in the annular groove (30) of the shoulder of the second element (20), the latter being closed by an end face (32).
6. Method of making a can according to Claim 3 or 5, characterized in that the flat annular bead (36) overlaps both the peripheral rim (26) of the lid and the outer face of the inwardly projecting rim (19) of the can body.
7. Method of making a can according to Claim 3 or 5, characterized in that the expansion of the tubular wall (10) and of the inwardly projecting rim (18) or of the tubular wall of the first element (16) is less than approximately 15%.
8. Method of making a can according to any one of the preceding claims, characterized in that in addition steps are formed in the end wall (12).
9. Can for food preserves comprising a body (34), an end face (32) and a lid (22), characterized in that the body (34) comprises a peripheral skirt (4) and an inwardly projecting rim (19) equipped with an annular groove (30), and in that the lid (22) is equipped with a peripheral rim (26) intended to interact with the inwardly projecting rim (19) of the body, the can additionally including a flat annular attaching bead (36) overlapping both the peripheral rim (26) of the lid and the outer face of the inwardly projecting rim (19) of the body of the can.
10. Can according to Claim 9, characterized in that the bead (36) is thermally sealed.
11. Can according to Claim 9, characterized in that the bead (36) is bonded.
12. Can according to one of Claims 9 to 11, characterized in that the bead (36) is made of aluminium.
13. Can according to one of Claims 9 to 11, characterized in that the bead (36) is made of plastic.
14. Can according to one of Claims 9 to 11, characterized in that the bead (36) is made of a material combining aluminium and plastic.

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