EP0363285B1 - Easy to open aluminium protective capsule, and process for its manufacture - Google Patents

Abstract

The invention relates to an aluminium or alloy protective capsule, intended to be crimped onto the neck of a bottle whose ring comprises a shoulder, the skirt (14) of this capsule comprising a peripheral bead (19) or rib (19) which, after the capsule has been crimped onto the neck, will with that portion of the said skirt (14) which covers the upper edge of the said shoulder of the neck delimit an annular groove (20) which can be used to guide a blade to cut the capsule, and also a line of weakness consisting of a thinner peripheral zone in the innermost part (21) of the said groove (20). <??>The invention also relates to the process of obtaining this capsule, which is used for any protection of a bottle that is to be uncapped with a knife. <IMAGE>

Description

The present invention relates to overcapping capsules, typically used for overcapping corked wine bottles with a cork stopper fully inserted into the neck, these capsules being able to be cut like traditional overcapping capsules made of tin plated lead. The invention also relates to their manufacturing process.

The overcapping capsule traditionally used for wine bottles and in particular for high-end wines, is a tin-plated lead capsule, obtained by drawing, drawing or flow-turning.

• découpage sur le raccordement supérieur de l'épaulement de la bague du goulot (terminologie EUCAPA), épaulement souvent appelé "bague de la verrerie";
• découpage sur le bord de l'extrémité supérieure du goulot.

We proceed to the uncapping of this capsule set on the neck of a bottle with a knife according to one of the two techniques below:

• cutting on the upper connection of the shoulder of the neck ring (EUCAPA terminology), shoulder often called "glassware ring";
• cutting on the edge of the upper end of the neck.

• de la faible résistance à la coupe du plomb plaqué d'étain,
• de la malléabilité de ce métal ne donnant pas alors de bavure coupante.

In both cases, this operation does not cause any difficulty because:

• low resistance to cutting tin-plated lead,
• the malleability of this metal does not give a sharp burr.

To face the problems of environmental protection and of the consumer, tending to limit the use of lead, the plaintiff sought to develop a metal overcap capsule which can be cut in the same way as the traditional capsules with lead base, i.e. with a knife.
There are also easy-open aluminum overcap capsules with peripheral tear-off tabs. Such capsules are described in document FR-B-2 548 164 and do not respond to the problem posed.

STATEMENT OF THE INVENTION

The first object of the invention is an aluminum or aluminum alloy overcap capsule comprising a head and a skirt, intended to be crimped onto the neck of a bottle whose ring has a shoulder, the skirt of said capsule comprising a peripheral line of weakness located above said shoulder of the neck ring when the capsule is crimped onto the neck, as it is known for example from document FR-B-2 548 114- According to the invention, in order to be easy to cut with a knife like a lead-based capsule, the skirt of this aluminum capsule also includes a ring or a peripheral rib which, after crimping the capsule on the neck, will delimit with the portion of said skirt covering the upper edge of said shoulder of the neck an annular groove allowing the guiding of a blade for cutting the capsule, and the line of weakness of the capsule consists of a thinned peripheral zone situated e at the bottom of said groove.

It should be noted that the aluminum or alloy overcap capsule is obtained by severe conformations, typically successive stamping and drawing, and that it must therefore have a minimum skirt thickness of the order of 0.08 to 0.10 mm. The Applicant's tests have shown that such a capsule, annealed and then crimped onto a neck, gives unacceptable difficulties for manual cutting with the knife described above: the cutting force is too great, and there is a risk of accidental cutting. of the user on the edges resulting from the cutting.

The overcap of the invention overcomes these two difficulties: the cutting of the bottom of the annular groove between the chamfer corresponding to the top of the neck shoulder and the peripheral ring is easy thanks to the thinning of this bottom , and also because the sides of this annular groove constitute a kind of hollow rail allowing a comfortable and safe guiding and sliding of the knife blade of the user, the cutting edge of this blade coming to bear on the thinned zone, or to immediate proximity of this area which still allows the division as we will see later -

The ring shows the cutting zone, located as above just above the upper chamfer of the neck shoulder, and the blade of the knife is, as usual, in contact with the covering of this shoulder, with the addition of a guide means (the rib) which prevents skidding or holding the blade too obliquely.

Furthermore, the position of the cutting or cutting / tearing line near the upper chamfer of the shoulder and set back from this chamfer is inaccessible or very inaccessible to the fingers of the user, so that the risks of injuries on the cutting edges are practically eliminated.

The easy cutting zone of the invention is continuous and is broken by cutting and possibly tearing, while the conventional line of weakness of an aluminum capsule is discontinuous and has breakable bridges which are broken by traction / shearing.

The hollow annular zone forming a guide rail must allow the insertion of the blades of common knives, in particular kitchen knives and pocket knives. The bottom of this annular zone or rail, the sides of which form a slightly enlarged entry, has a width, or "height" along the longitudinal axis of the supposed vertical capsule, between 0.5 and 2.5 mm, and preferably chosen between 0.8 and 1.8 mm in order to give tighter guidance of the knife blades common for this use. These blades have in fact, at 0.5 to 1.5 mm from their cutting edge, a thickness typically between 0.5 and 1 mm.

• soit une entaille ou incision en forme de gorge intérieure laissant une épaisseur minimale résiduelle de jupe comprise entre 0,02 et0,07 mm, et de préférence entre 0,025 mm et 0,04 mm, pour assurer le meilleur compromis entre tenue mécanique au sertissage et facilité de découpage;
• soit une surface intérieure continue, sans formation de gorge interieure, laissant une épaisseur minimale résiduelle de jupe comprise entre 0,02 et 0,07 mm sur une hauteur selon l'axe longitudinal d'au moins 0,4 mm et le plus souvent limitée à moins de 1,4 mm (voir l'exemple d'obtention).

The thinned peripheral zone of the bottom of the annular groove comprises:

• either a notch or incision in the form of an internal groove leaving a minimum residual skirt thickness of between 0.02 and 0.07 mm, and preferably between 0.025 mm and 0.04 mm, to ensure the best compromise between mechanical resistance to crimping and ease of cutting;
• or a continuous interior surface, without formation of an internal groove, leaving a minimum residual skirt thickness of between 0.02 and 0.07 mm over a height along the longitudinal axis of at least 0.4 mm and most often limited less than 1.4 mm (see example for obtaining).

Tests have shown that in the case of a notch or incision in the form of an internal groove, this facilitates cutting by a knife even if the blade of this knife is offset by 0.5 mm or a little more with respect to the back of the throat or incision corresponding to the minimum thickness. With this offset, the knife blade still produces an easy cutting by effect of external notch and tearing.

The same is true for a thinned zone with a continuous internal surface without a throat of limited height, but it is important to note that this type of thinning makes it possible to eliminate any relative cutting difficulty which would be due to a problem of centering precision. of the knife blade by choosing a sufficient thinning height. Thus if the reference thickness of the knife blade is 1 mm and the height of the annular groove of 1.5 mm, the maximum play or offset of the blade in this groove will be 0.5 mm and it will suffice d '' have a thinned zone centered at the bottom of the groove and height along the axis of at least 0.5 mm to eliminate possible cutting irregularities, the cutting edge of the knife then being necessarily on the thinning of the skirt.

The annular groove being limited on the side of the head of the capsule by the ring or peripheral rib, the importance of this ring or rib identified by its external diameter depends on two factors: the quality of the guiding of the blade of the knife, and the outside decoration usually applied before the execution of this ring. It has been found that the outside diameter of this rod should be 1 to 3 mm greater than the diameter of the capsule skirt next to the rod, and preferably only 1 to 2 mm greater than this skirt diameter so as to better preserve the decoration. The rod then typically has a height along the longitudinal axis of between 0.5 and 2 mm and most often between 0.5 and 1 mm. It has been observed that the absence of a rod or rib leads to frequent slippage of the knife blade.

A second object of the invention is the method of manufacturing the preceding aluminum or alloy overcap capsule.

• a) on prépare un poinçon rentrant dans ladite capsule, ce poinçon comportant, entre une portion inférieure et une portion de tête que coiffera la tête de la capsule, une portion à pourtour arrondi dépassant la portion de tête d'au moins 0,5 mm au rayon, et entre cette portion à pourtour arrondi et la portion inférieure une portion en retrait comportant une portion saillante en retrait d'au moins 0,25 mm au rayon par rapport à ladite portion arrondie;
• b) on prépare une molette comportant au moins une portion supérieure d'appui du haut de la capsule emboîtée sur le poinçon et une portion de formage et d'appui de ladite capsule dans la portion annulaire en creux du poinçon, le diamètre extérieur de cette portion de formage et d'appui étant choisi de façon à ce qu'elle vienne à 0,02 à 0,07 mm de la portion saillante de ladite portion en retrait lors d'un appui radial de la molette contre la portion de tête du poinçon revêtue de la capsule;
• c) on coiffe le poinçon avec la capsule;
• d) on applique la molette contre le poinçon revêtu de la capsule en les faisant tourner l'un par rapport à l'autre, la portion de formage et d'appui de la molette venant alors s'appuyer sur la capsule au droit de la portion en retrait du poinçon tandis que sa portion supérieure vient s'appuyer contre la tête de la capsule coiffant la portion de tête du poinçon;
• e) on écarte la molette du poinçon revêtu, et après arrêt suffisant de la rotation on extrait la capsule du poinçon.

In this process, a blank blank was previously transformed into aluminum or an alloy in an overcap capsule comprising a head and a skirt: according to one of the usual methods, that is to say by flow spinning or by stamping-drawing. The complementary forming of the invention, done on the capsule obtained annealed or not yet annealed, usually decorated, comprises the following operations:

• a) a punch is prepared which fits into said capsule, this punch comprising, between a lower portion and a head portion which the head of the capsule will cover, a portion with a rounded periphery exceeding the head portion by at least 0.5 mm to the radius, and between this portion with a rounded periphery and the lower portion, a recessed portion comprising a projecting portion recessed by at least 0.25 mm to the radius relative to said rounded portion;
• b) a thumbwheel is prepared comprising at least an upper support portion from the top of the capsule fitted onto the punch and a forming and support portion of said capsule in the hollow annular portion of the punch, the outside diameter of this forming and support portion being chosen so that it comes to 0.02 to 0.07 mm from the projecting portion of said recessed portion when the wheel is pressed radially against the head portion of the punch coated with the capsule;
• c) the punch is capped with the capsule;
• d) the wheel is applied against the punch coated with the capsule by rotating them relative to each other, the forming and support portion of the wheel then coming to bear on the capsule in line with the recessed portion of the punch while its upper portion bears against the head of the capsule covering the head portion of the punch;
• e) the wheel of the coated punch is moved aside, and after sufficient stop of the rotation the capsule is extracted from the punch.

The shaping of the easy cutting zone with a knife of the overcap capsule is thus obtained with a simple and rapid device, by forming the zones of successive support of the capsule on the punch.

• des portions en V avec arête d'extrémité de rayon compris entre 0,03 et 0,08 mm;
• des portions arrondies, avec ou sans petit plat central.

The bottom of the annular groove formed on the capsule is weakened by thinning between the protruding portion of the punch and the forming and supporting portion of the wheel, and it has been found that these two types of protruding portion are particularly suitable (profiles in axial section):

• V-shaped portions with an end edge of radius between 0.03 and 0.08 mm;
• rounded portions, with or without a small central dish.

To preserve the coating and easily extract the capsule from the punch after shaping, it is preferable to limit the radial protrusion of the rounded part of the punch forming the rib of the invention, and it has been found that an overshoot of 0.5 to 1.2 mm in radius from the head portion of the punch, corresponding to the same protrusion of the rib formed on the capsule, led to a correct extraction of the capsule from the mandrel while giving effective guidance of the cutting blade of the capsule on the bottle.

The examples and the drawings which illustrate them will make it possible to better understand the invention and to specify certain points thereof.

TESTS AND EXAMPLES

• Figure 1 shows an overcap capsule according to the invention, in axial section.
• Figure 1a shows the details of the opening device of this capsule, enlarged.
• Figure 2 shows a similar capsule set on a bottle, in axial section.
• FIG. 3 represents the tools for producing the device for easily opening these capsules in the working position, in section through the plane passing through the axes of symmetry and rotation of the punch and of the wheel of this device.
• Figure 4 shows a variant of these tools, the projecting portion of the punch having a rounded profile.

FIRST EXAMPLE

• A/ On a serti 5 de ces capsules sur des bouteilles vides (non représenté), et on a essayé de les découper avec une lame de couteau s'appuyant sur le chanfrein 4 de base du rétreint de tête de la capsule, ce chanfrein 4 s'appuyant lui-même sur le bord supérieur ou chanfrein supérieur 5 de l'épaulement 2 de la bague de la bouteille (même disposition que sur la figure 2). Après des essais infructueux, on est arrivé à couper deux capsules moyennant un effort important sur le couteau, effort inacceptable en pratique;
• B/ On a effectué un façonnage complémentaire de 10 capsules 6 sur un dispositif comprenant un poinçon rotatif 7 et une molette folle 8. Le poinçon 7 (figure 3) comprend des bagues empilées permettant de s'adapter facilement au type de capsule; à savoir en partant de la tête: des bagues de tête 9 et 9′ de diamètre 26,03 mm et de hauteur totale 4 mm, une bague plate 10 de hauteur selon l'axe 0,6 mm et de surface de pourtour arrondie de rayon 0,3 mm en section axiale et de diamètre extérieur 27,2 mm; puis une bague 11 de hauteur 1,4 mm comportant en section axiale un profil d'extrémité 12 en V à 90° avec un rayon d'extrémité ou arête de 0,05 mm, avec un diamètre extérieur de 26,16 mm; puis une portion 13 supportant la jupe 14 de la capsule 6 dans ses zones d'appui successif sur le mandrin 7 et préservant l'engagement correct de cette capsule 6 sur la bouteille lors du sertissage.
  La molette 8 qui vient s'appliquer contre le haut de la capsule 6 comprend ici une portion supérieure d'appui 16 de diamètre 40, puis une gorge 17 de profondeur 2 mm et de largeur 1 mm, puis une bague 18 de hauteur 1 mm et de diamètre 40 mm.
  Chaque capsule 6 est placée sur le poinçon 7 et, ce poinçon étant entraîné en rotation, la molette 8 est rapprochée jusqu'à ce que sa portion supérieure 16 s'appuie contre la tête de la capsule 6 elle-même bloquée sur la tête 9 et 9′ du poinçon 7. Dans cette position, la gorge 17 de la molette est centrée sur la bague de pourtour arrondi 10 du poinçon, tandis que sa bague 18 écrase la jupe 14 de la capsule 6 sur le pourtour en V de la bague 11. On reste dans cette position un à plusieurs tours et on dégage la molette et la capsule.

Aluminum capsules obtained by stamping and drawing and annealing were used, with an inner end diameter (near the bottom) 29.5 mm, with a neck shrinkage 6 mm high, corresponding to bottles of wine 1 with a ring. comprising a single shoulder 2 of total height 10 mm and above an end portion 3 of total height 6 mm (Figure 2).
These capsules were in the annealed condition and their 0.10 mm thick skirts were conical for stacking in a "stick".

• A / We crimped 5 of these capsules on empty bottles (not shown), and we tried to cut them with a knife blade resting on the base chamfer 4 of the cap neck constriction, this chamfer 4 resting itself on the upper edge or upper chamfer 5 of the shoulder 2 of the ring of the bottle (same arrangement as in FIG. 2). After unsuccessful tests, we managed to cut two capsules with a significant effort on the knife, effort unacceptable in practice;
• B / A complementary shaping of 10 capsules 6 was carried out on a device comprising a rotary punch 7 and a crazy wheel 8. The punch 7 (FIG. 3) comprises stacked rings making it possible to easily adapt to the type of capsule; namely from the head: head rings 9 and 9 ′ with a diameter of 26.03 mm and a total height of 4 mm, a flat ring 10 with a height along the axis 0.6 mm and a rounded perimeter surface of radius 0.3 mm in axial section and external diameter 27.2 mm; then a ring 11 of height 1.4 mm comprising in axial section an end profile 12 in V at 90 ° with an end radius or edge of 0.05 mm, with an outside diameter of 26.16 mm; then a portion 13 supporting the skirt 14 of the capsule 6 in its successive bearing zones on the mandrel 7 and preserving the correct engagement of this capsule 6 on the bottle during crimping.
  The thumb wheel 8 which is applied against the top of the capsule 6 here comprises an upper support portion 16 of diameter 40, then a groove 17 of depth 2 mm and width 1 mm, then a ring 18 of height 1 mm and diameter 40 mm.
  Each capsule 6 is placed on the punch 7 and, this punch being driven in rotation, the wheel 8 is brought together until its upper portion 16 bears against the head of the capsule 6 itself blocked on the head 9 and 9 ′ of the punch 7. In this position, the groove 17 of the thumbwheel is centered on the rounded perimeter ring 10 of the punch, while its ring 18 crushes the skirt 14 of the capsule 6 on the V-shaped periphery of the ring 11. We remain in this position one to several turns and we release the wheel and the capsule.

Examination of the capsules 6 after disassembly (Figures 1 and 1a) shows the following modifications:
shaping of a circular embossed rod 19 with an external diameter of 29.5 mm and a height of 1 mm, and of an annular groove 20 between the rod 19 and the chamfer 4 of the base of the head constriction of the capsule 6. The bottom 21 of this groove 20 has a diameter of 28.3 mm and a height of 0.8 mm.
On the inside (opening of 2 capsules), this bottom 21 has an internal V-shaped groove 22 and its residual thickness at the bottom of this groove is 0.035 mm, which corresponds to half the difference (26.03 + 2 x 0 , 1 - 26.16) mm.

où h est la hauteur de la portion d'extrémité du goulot de la bouteille au-delà de son épaulement (figure 2), et e l'épaisseur de la jupe 14 de la capsule 6.
Ici h = 6 mm; d_N = 4,6 mm; et e = 0,1 mm, de sorte que la hauteur F du fond 21 de la gorge annulaire 20 est de 1,2mm. Cette hauteur est déjà réglée au stade du façonnage complémentaire, la hauteur du mandrin 7 au-dessus de la portion inférieure 13 étant de 6 mm, et le sertissage devant opérer seulement à ce niveau une déformation en tronc de cône du bord inférieur 4 de la gorge annulaire 20 sur le chanfrein supérieur 5 de l'épaulement 2 (figure 2), sans changement sensible de la hauteur du fond 21 de cette gorge 20. La position du bord inférieur 4 de la gorge 20 étant ainsi définitive, la hauteur F du fond 21 est aussi pratiquement égale à la hauteur de la portion de formage 18 de la molette 8 (figure 4).The 8 unopened capsules for internal examination were crimped onto bottles using a tip protecting the easy-cut profiled area thus produced on each capsule.
The cutting with a pocket knife of the overcapping capsules thus crimped gave a clear separation of the head from the capsule, with moderate pressure on the knife blade.
It is noted that, here and in the general case, the spacing "d" of the upper end of the punch 7 and of the median plane of the recessed portion 11 or 111 defines the average distance from the thinned peripheral zone of the capsule 6 at the end of the neck of the bottle 1 on which it is crimped. The distance "d" between the end of the punch 7 and the lower surface of the rounded-edge portion 10, which is the junction plane of this portion 10 and the recessed portion 11 or 111, adjusts the position of the lower edge of the peripheral rib 19, and the bottom 21 of the annular zone 20 of the crimped capsule has a width or height along the longitudinal axis equal or slightly less (in practice at most 0.5 mm), to:

${\text{F = h - d}}_{\text{NOT}}\text{- 2 xe (mm)}$

where h is the height of the end portion of the neck of the bottle beyond its shoulder (FIG. 2), and e the thickness of the skirt 14 of the capsule 6.
Here h = 6 mm; d _N = 4.6 mm; and e = 0.1 mm, so that the height F of the bottom 21 of the annular groove 20 is 1.2 mm. This height is already set at the stage of additional shaping, the height of the mandrel 7 above the lower portion 13 being 6 mm, and the crimping must operate only at this level in a truncated cone deformation of the lower edge 4 of the annular groove 20 on the upper chamfer 5 of the shoulder 2 (FIG. 2), without appreciable change in the height of the bottom 21 of this groove 20. The position of the lower edge 4 of the groove 20 thus being final, the height F of the bottom 21 is also practically equal to the height of the forming portion 18 of the wheel 8 (FIG. 4).

In the general case, the position of the lower edge 4 after further shaping can be shifted upwards by a few tenths of (mm, typically less than 0.5 mm, and then the height of the bottom of the annular groove is slightly increased by the crimping of the cap on the neck of the bottle. The adjustment of the annular groove by the choice of its calculated height F between 0.5 and 2.5 mm and preferably between 0.8 and 1.8 mm makes it possible to adjust the resulting height after crimping.

SECOND EXAMPLE

Capsules comprising the internal notch of the invention but not the guide rib 19 which is attached to it were produced from the same stamped-drawn capsules and after replacing the ring 10 of the punch with a ring with a diameter of 27.2 mm. associated: the knife of the user who wants to open the cap to uncork the bottle of wine slips easily, such a solution is to be avoided. The rod or rib 19 is necessary to obtain an easy cutting and without risk of accidental cutting of the user.

THIRD EXAMPLE

We took 10 capsules 6 from the already supplied series and we made on these capsules a complementary shaping identical to that of the first example, except for the following change:
the ring 11 of the punch 7 (FIG. 3) has been replaced by a ring 111 of the same height 1.4 mm and of rounded peripheral surface 112 and of external diameter 26.16 mm (FIG. 4). As can be seen in this FIG. 4, the work of shaping the skirt 14 between the periphery of the ring 18 of the knob 8 and the rounded periphery 112 of the ring 111 of the punch 7 produces a crushing of the skirt 14 combined with a pulling, the thinning product resulting from the two processes. After this shaping, the thickness in the middle of the bottom of the annular groove 22 is (26.03 + 2 x 0.1 - 26.16) x 0.5 = 0.035 mm as before, and it is observed that the thickness residual of the bottom 21 is less than 0.05 mm by at least 0.8 mm in height.
After crimping on bottles, these capsules were easily cut with a knife, as before.

USE AND BENEFITS

The capsules and the method of the invention are used for any overcapping of bottles to be opened with a knife.
The thickness of the capsules is usually between 0.08 and 0.3 mm and they are made of lightly loaded aluminum, typically comprising more than 97% Al.

In addition to their ease of additional shaping and then cutting with a knife in the traditional location, it should be noted that these capsules do not use lead (ecological interest).

Claims (12)

1. Aluminium or aluminium alloy closure capsule (6) comprising a head and a skirt (14) adapted to be crimped onto the neck of a bottle (1) of which the ring comprises a shoulder (2), the skirt (14) of the said capsule (6) comprising a peripheral line of weakness situated above the said shoulder (2) of the ring of the neck when the capsule (6) is shrunk onto the neck, characterised in that its skirt (14) also comprises a retaining ring (19) or a peripheral rib (19) which, after the capsule (6) has been crimped onto the neck, will define with the portion (4) of the said skirt (14) which covers the top edge (5) of the said shoulder (2) of the neck an annular groove (20) which makes it possible to guide a blade to cut the capsule (6) and in that the line of weakness on the capsule consists of a thinned peripheral zone situated in the bottom (21) of the said groove (20).
2. A capsule according to Claim 1 in which the bottom (21) of the said annular groove (20) has a height comprised between 0.5 and 2.5 mm.
3. A capsule according to Claim 2 in which the bottom (21) of the said annular groove (20) has a height of between 0.8 and 1.8 mm.
4. A capsule according to any one of Claims 1 to 3 in which the thinned peripheral zone of the bottom (21) of the said annular groove (20) comprises a notch or incision (22) in the form of an interior groove leaving a minimum residual thickness of skirt (14) of between 0.02 and 0.07 mm.
5. A capsule according to Claim 4, the minimum residual thickness of skirt (14) of which is comprised between 0.025 and 0.04 mm.
6. A capsule according to any one of the Claims 1 to 3 in which the thinned peripheral zone of the bottom (21) of the said annular groove (20) comprises a continuous interior surface with no formation of interior groove (20), leaving a minimum residual thickness of skirt (14) of between 0.02 and 0.07 mm over a longitudinal axial height of at least 0.4 mm.
7. A capsule according to any one of Claims 4 to 5, having a retaining ring or a peripheral rib (19) with an outside diameter which is 1 to 3 mm greater than the diameter of the skirt (14) on the same side as the said retaining ring or the said rib (19).
8. A method of producing an aluminium or an aluminium alloy capsule (6) adapted to be crimped onto the neck of a bottle (1) of which the ring comprises a shoulder (2) in which an aluminium or alloy blank is converted to a capsule (6) comprising a head and a skirt (14), characterised in that then:

   a) a stamp (7) is prepared which enters the said capsule (6), the stamp (7) comprising between a bottom portion (13) and a head portion (9 and 9') a portion (10) with a rounded periphery which projects beyond the head portion (9') by at least 0.5 mm in radius and between this portion of rounded circumference (10) and the bottom portion (13) there is a set-back portion (11, 111) comprising a projecting portion (12, 112) set back by at least 0.25 mm in radius in relation to the said portion of rounded periphery (10);

   b) similarly, a roller (8) is prepared which has to be applied radially against the stamp (7) surmounted by the capsule (6) and comprising at least one upper portion (16) for supporting the top of the capsule (6) which is thus fitted onto the stamp (7) and a portion (18) for forming and supporting the said capsule (6), applying it against the set-back portion (11, 111) of the stamp (7), the outside diameter of this shaping and supporting portion (18) being so chosen that this portion (18) comes to within 0.02 to 0.07 mm of the projecting portion (12, 112) of the said set-back portion (11, 111) during the said radial bearing;

   c) the capsule (6) is fitted over the top of the stamp (7);

   d) the roller (8) is applied against the stamp (7) which is covered with the capsule (6), the shaping and bearing portion (18) of the roller (8) being applied against the skirt (14) of the capsule (6) at right-angles to the set-back portion (11 and 12, 111 and 112) of the stamp (7) and its top portion (16) bearing against the head of the capsule (6) covering the head portion (9 and (9') of the stamp (7), the said roller (8) and the said stamp (7) causing the one to rotate against the other;

   e) the roller (8) is moved away from the stamp (7) which is thus covered, and then the capsule (6) is removed from the stamp (7).
9. A method according to Claim 8 in which the said projecting portion (12) of the set-back portion (11) comprising in cross-section a V-shaped end profile (12) with an end radius of between 0.03 and 0.08 mm.
10. A method according to Claim 8 in which the said projecting portion (112) of the set-back portion (110) of the stamp (7) comprises in cross-section a rounded profile (112).
11. A method according to Claim 8 in which the rounded portion (10) of the stamp (7) projects beyond its head portion (9') by 0.5 to 1.2 mm in radius, in order to facilitate extraction of the capsule (6) from the stamp (7).
12. A method according to any one of Claims 8 to 11 in which the height (F) of the annular groove (20) in the capsule (6) crimped onto the neck of a bottle (1) is regulated directly according to the height (h) of the end portion of this neck above its shoulder (2) and regulating the distance (d_N) between the bottom surface of the rounded edge portion (10) and the top end of the stamp (7) so that:
    
    ${\text{F = h - d}}_{\text{N}}\text{- 2 x e,}$

    

    
    
       in which e is the thickness of the skirt (14) of the capsule (6), in other words between 0.5 and 2.5 mm and preferably between 0.8 and 1.8 mm.

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