EP1360118B1 - Closure cap comprising means for securing a moulded joint - Google Patents

Abstract

The invention concerns a closure cap comprising a terminal transverse wall (3) and a cylindrical skirt (4) including, on its inner surface, a thread designed to co-operate with a complementary outer thread of a container neck. The closure is designed to receive a moulded joint (15) extending substantially on the entire inner surface (16) of the transverse wall (3), over a substantially constant thickness. The transverse wall (3) comprises, on its inner surface (16), at least a projection (17) forming catching means for the joint (15), thereby ensuring retention of the joint (15) against the transverse wall (3). The axial height of the projection (17) is less than the thickness of said joint (15).

Description

The invention relates to an assembly comprising a stopper and a joint by pouring into the bottom of the stopper, as well as a method for carrying out of such a plug.

The invention relates more particularly to plastic plugs comprising a cylindrical skirt and a transverse end wall, the seal being cast against said transverse end wall.

We already know such plugs, in which the implementation of the seal is done by deposition of a certain volume of constituent material of the gasket on the wall transversal, using a dispenser.

The deposited material is hot, liquid or pasty, and therefore spreads on the inner face of the transverse wall. The seal is then compressed against the transverse wall using a tool. It then occurs a physicochemical bonding the seal cast on the inner face of the transverse wall.

In the prior art, the cast seal is held against the transverse wall only by this force of physicochemical adhesion.

However, the adhesion of the seal to the transverse wall is not optimal. he happens in fact that the seal is detached from the said wall, and can escape of the stopper, in particular during the storage of the cap-seal assembly and transport for mounting on a container neck. The seal between the cap and the container neck on which it is mounted can no longer be assured.

Several solutions have been considered to solve this problem.

US 4,697,716 discloses a plug having a groove on the face its transverse wall and intended to receive a seal cast in this throat. The groove is delimited by two substantially axial walls: on the one hand the skirt of the cap and on the other hand an annular projection.

The annular projection may have a surface having a certain inclination with respect to the transverse wall of the plug, so as to allow the attachment of the seal and to avoid its axial displacement towards the opening of the plug.

However, the annular projection is placed with respect to the axis of the plug of way that, once the seal is poured into the groove, and when the cap is screwed on a container neck, the seal is located opposite the rim of the neck of the container.

• d'une part, la saillie doit présenter une hauteur axiale suffisamment importante pour permettre de délimiter une gorge et de contenir le joint dans cette gorge. Lorsque le bouchon est vissé sur le col de récipient, le joint est comprimé de sorte qu'il présente localement une épaisseur inférieure à la hauteur axiale de la saillie, et reste maintenu dans la gorge ;
  d'autre part, la position de la saillie doit être précise. En particulier, la saillie ne doit pas présenter un diamètre trop faible, ceci pouvant nuire à un bon maintien du joint dans la gorge. A l'inverse, la saillie ne doit pas présenter un diamètre trop important, car elle risquerait de ce cas de se trouver en regard du rebord du col du récipient, ce qui nuirait à l'étanchéité. De plus, compte tenu de la hauteur axiale de la saillie, le vissage du bouchon sur le col pourrait endommager la saillie.

As a result, the projection must meet a number of criteria:

• on the one hand, the projection must have an axial height large enough to delimit a groove and contain the seal in this groove. When the cap is screwed onto the container neck, the seal is compressed so that it has locally a thickness less than the axial height of the projection, and remains in the groove;
  on the other hand, the position of the projection must be precise. In particular, the protrusion must not have a too small diameter, this may be detrimental to a good maintenance of the seal in the groove. Conversely, the protrusion should not have too large a diameter, because it might be in this case to be opposite the rim of the neck of the container, which would affect the seal. In addition, given the axial height of the projection, screwing the cap on the neck could damage the projection.

Thus, in document US Pat. No. 4,697,716, the projection serves both to hook the seal and sealing the plug. Because of this, the characteristics dimensioning of the projection must be precise, the plug molding being therefore made more complex.

The document GB 1 224 669 discloses a cap according to the preamble of the appended claim 1, having an annular projection on the internal face of its transverse wall, the projection being intended to serve as a means for attaching a seal to the bottom of the cap . This document also describes a method according to the preamble of claim 13.
A seal is poured into the bottom of the plug and then stamped, so as to match the shape of the inner face of the transverse wall and the projection. The seal thus has an annular boss at the projection.

The seal is intended to come into contact with the rim of a container neck at level of this boss. Therefore, the projection is placed so as to be in view of the rim of a container neck when the plug is associated with said neck.

In a similar manner to US Pat. No. 4,697,716, the manufacture of the cap described in GB 1 224 669 is relatively complex. Indeed, the projections must be positioned and molded in a very precise way, since they play a fundamental role for sealing.

In addition, the stamping of the seal must also be carried out accurately, the surface state of the gasket at the level of the protrusion must make it possible to guarantee a good sealing. This stamping therefore constitutes an additional operation generating additional costs and longer manufacturing times.

As for the document GB 2 111 965, it describes a stopper, provided with lips sealing means for cooperating with the rim of a container neck. When the cap is placed on the neck, the lips are bent and applied against this rim, so as to seal. In order to ensure a good despite the rigidity of the lips, document GB 2 111 965 provides for cover the lips with a thin film of a softer material allowing to improve the contact between the lips and the rim of the neck.

The flexible material covers the lips forming a ring at the bottom of the plug. The ring has a curved surface or a wedding shape perfectly the shape of the projections.

However, the purpose of GB 2 111 965 is to improve the sealing of caps with sealing lips but without seal. It does not offer an effective solution to the problem of attachment of a seal cast against the transverse wall of a plug.
The object of the invention is to solve the problems posed by the prior art by providing a stopper - associated with a cast seal - in which the functions of attachment of the seal and sealing are dissociated.

• un bouchon du type comportant une paroi transversale d'extrémité et une jupe cylindrique comprenant, sur sa face interne un filetage destiné à coopérer avec un filetage complémentaire externe d'un col de récipient ;
• et un joint placé contre la face interne de la paroi transversale du bouchon, le joint ayant été mis en place par coulage et s'étendant sensiblement sur toute la face interne de la dite paroi transversale la paroi transversale du bouchon comprend, sur sa face interne, au moins une saillie formant moyen d'accrochage pour le joint, la dite saillie étant enrobée et recouverte par le joint, le joint présentant la forme générale d'un disque d'épaisseur sensiblement constante, et la hauteur axiale de la saillie étant inférieure à l'épaisseur du dit joint.

For this purpose, and according to a first aspect, the invention relates to an assembly comprising:

• a plug of the type comprising a transverse end wall and a cylindrical skirt comprising, on its internal face, a thread intended to cooperate with an external complementary thread of a container neck;
• and a seal placed against the internal face of the transverse wall of the plug, the seal having been put in place by casting and extending substantially over the entire internal face of said transverse wall, the transverse wall of the plug comprises, on its internal face at least one projection forming attachment means for the seal, said protrusion being coated and covered by the seal, the seal having the general shape of a disc of substantially constant thickness, and the axial height of the projection being less than to the thickness of the said seal.

This makes it possible to overcome the constraints of positioning accurate hooking projections, and thus to achieve a cap according to a simpler and less restrictive process.

According to one embodiment of the invention, the projection comprises at least one inclined face of an acute angle relative to the axis of the plug so that when the seal is placed in the plug, at least one zone of said seal is included in a zone latch located axially between the transverse wall and a part of the said projection.

According to a first embodiment, the projection has, in axial section, the shape of at least one trapezium whose small base is located towards the free end of the said projection, said trapezium being such that one of the two angles adjacent to the small base is acute. One of the two angles adjacent to the small base is between 40 ° and 80 °, especially close to 60 °.

According to a second embodiment, the projection has, in axial section, the shape at least one trapezium whose large base is located towards the free end of the said projection. For example, said trapezoid has an axis of symmetry substantially parallel to the axis of the plug.

According to one possible embodiment, the projection is annular and substantially axis confused with the axis of the cap.

The cap may comprise two annular projections substantially concentric, of axis substantially coincident with the axis of the plug, the free ends of the two projections being for example axially offset one compared to each other.

According to other features, the projection may have an axial height less than half to one third of the thickness of the transverse wall of the plug.

According to a second aspect, the invention relates to a set of parts cap and a seal, as previously described, and on the other hand a collar of container or receptacle having a neck, the receptacle being empty or at least partially filled with some content.

• on réalise par moulage un bouchon comprenant au moins une saillie ;
• on dépose au fond du bouchon un certain volume de matière constitutive du joint sous forme liquide ou pâteuse, de sorte que la matière s'étale sur la face interne de la paroi transversale du bouchon, enrobe et recouvre la saillie, le dit volume étant suffisant pour que l'épaisseur du joint soit supérieure à la hauteur axiale de la saillie.

Finally, according to a third aspect, the invention relates to a method for producing a plug-and-seal assembly comprising the following steps:

• a plug is produced by molding comprising at least one projection;
• at the bottom of the cap is deposited a certain volume of constituent material of the seal in liquid or pasty form, so that the material spreads on the inner face of the transverse wall of the plug, coats and covers the projection, said volume being sufficient so that the thickness of the seal is greater than the axial height of the projection.

Once the constitutive material of the seal deposited at the bottom of the cap, one can compressing said material against the transverse wall of the stopper.

• la figure 1 est une vue en coupe axiale d'un bouchon présentant des saillies selon un premier mode de réalisation, le dit bouchon comportant un joint coulé contre sa paroi transversale ;
• la figure 2 est une vue du détail A de la figure 1 ;
• la figure 3 est une vue en coupe axiale partielle d'un bouchon présentant des saillies selon une variante d'un premier mode de réalisation ;
• la figure 4 est une vue du détail B de la figure 3 ;
• la figure 5 est une vue en coupe axiale partielle d'un bouchon présentant des saillies selon un deuxième mode de réalisation ;

The other features of the invention result from the following description of embodiments, description made with reference to the appended figures in which:

• Figure 1 is an axial sectional view of a cap having projections according to a first embodiment, said plug having a seal cast against its transverse wall;
• Figure 2 is a view of detail A of Figure 1;
• Figure 3 is a partial axial sectional view of a cap having projections according to a variant of a first embodiment;
• Figure 4 is a detail view B of Figure 3;
• Figure 5 is a partial axial sectional view of a cap having projections according to a second embodiment;

Referring first to Figure 1 which shows a plug 1 of axis 2, the plug 1 being for example made of plastic.

The plug 1 comprises firstly a transverse end wall 3, substantially discoidal, and a cylindrical skirt 4 protruding substantially perpendicular to the transverse wall 3.

The cylindrical skirt 4 comprises, on its outer face 5, notches 6 intended for facilitate the screwing and unscrewing of the cap 1 by a user, and, on his inner face 7, a thread 8 intended to cooperate with the external thread of a container neck not shown.

The plug 1 also comprises an annular band 9 of tamper, connected at the free end 10 of the cylindrical skirt 4 by frangible bridges 11 or by a line of weaker resistance. The tamper-evident band 9 has latching projections 12, directed towards the axis 2 of the plug 1, and intended for cooperate with the neck of a container to ensure the maintenance of the band at the neck of said container when, during the first opening of the said container, the bridges 11 are broken.

The plug 1 comprises locking elements 13, extending axially from the free end 10 of the cylindrical skirt 4 to and inside the tamper band 9, over a length such that the free end 14 of the said blocking element 13 is located, radially, opposite the band 9. The locking elements 13 are located towards the inside of the cap 1 with respect to the tamper band. 9. Their role is to guarantee the integrity of the tamper-evident band 9 and the bridges 11 during assembly of the cap 1 on the neck of the container for which it is intended.

The stopper 1 finally comprises a seal 15, put in place by casting against the transverse wall 3, which will be described in more detail later in the description.

The transverse wall 3 of the plug 1 has, on its inner face 16, one or several projections 17 forming hooking means of the seal 15, thus preventing the separation of said seal 15 of the transverse wall 3. The projections 17 are made by molding, with the stopper 1. They present a relatively low axial height, in particular less than half or even third, the thickness of the transverse wall 3 of the plug 1. In addition, the width protrusions 17 in cross section is also reduced.

The projections 17 are annular, of axis substantially coincident with the axis 2 of the cap 1.

A first embodiment of the projections 17 is now described with reference to FIGS. 1 to 4.
Figure 4 shows a projection 17 according to the first embodiment, in axial section.

The projection 17 has, in axial section, the shape of a trapezium, or rather of two trapezes symmetrical with respect to the axis of said protrusion 17.

The large base 18 of the trapezium is substantially merged with the wall transverse 3, the small base 19 of the trapezium constituting the free end of the 17. The small base 19 may be of very small length, so that the trapeze is like a triangle.

A first face 20 of the trapezium, distinct from the bases 18, 19, and located opposite of the axis 2 of the plug 1, is inclined relative to the transverse wall 3 of a angle α obtus, for example between 130 ° and 170 °, especially close to 150 °. A second face 21 of the trapezium, opposite the first face 20, is inclined relative to the transverse wall 3 by an acute angle β, for example between 40 ° and 80 °, in particular close to 60 °.

The angle between the transverse wall 3 and the second face 21 of the trapezium is round.

According to a first variant of this first embodiment, illustrated on the Figures 1 and 2, the transverse wall 3 of the cap 1 comprises three projections 17 annular, substantially concentric, axis substantially confused with the axis 2 of the plug 1. A first annular projection 17 has a radius substantially equal to half the radius of the transverse wall 3. Two additional projections 17, of close radius, are arranged towards the periphery of the transverse wall 3.

According to a second variant of this first embodiment, illustrated on the 3, the transverse wall 3 of the plug 1 comprises three projections 17 annular, substantially concentric, axis substantially confused with the axis 2 of the plug 1. A first annular projection 17 has a radius substantially equal to half the radius of the transverse wall 3. A protrusion 17 additional is arranged towards the periphery of the transverse wall 3.

With reference to FIG. 5, a second embodiment of FIG. making projections 17.

The projection 17 has, in axial section, the shape of a trapezium, or rather of two trapezes symmetrical with respect to the axis of said protrusion 17.

The small base 22 of the trapezium is substantially merged with the wall transverse 3, the large base 23 of the trapezium constituting the free end of the projection 17. The trapezium has an axis of symmetry 24 substantially parallel to the axis of the cap 1.

The faces 25, 26 of the trapezium distinct from the bases 22, 23 are inclined by relative to the transverse wall 3 of an acute angle γ, for example between 40 ° and 80 °, especially close to 60 °.

The establishment of the seal 15 is by depositing a certain volume of material at bottom of said plug 1. This deposit can be made from an extruder or a hot melt gun.

The constituent material of the seal 15, hot and liquid, or at least pasty, spread on the inner face 16 of the transverse wall 3, flows to protrusions 17, coats and covers them.

The seal 15 thus extends substantially over the entire inner face 16 of the wall transverse 3 of the plug 1, and has the shape of a disk, thick substantially constant over its entire surface.

The seal can then be compressed against the transverse wall by means of a tool, leaving an impression on the seal 15 as illustrated in FIG. 2. The volume of material deposited is sufficient for the thickness of the seal 15 to be greater at the axial height of the projections 17, even after compression.
This stamping makes it possible to give the seal 15 a shape perfectly adapted to the shape of the neck of the container to which the plug 1 is intended to be associated, in order to guarantee a very good seal. In addition, the stamping makes it possible to penetrate the projections 17 into the material constituting the seal 15.

The stamping of the seal 15, corresponding to a preferred embodiment of the invention, however, is optional, since it is not essential to the attachment of the seal 15 against the transverse wall 3 of the plug 1 with the help of protrusions 17.

With or without coining, the outer face of the seal 15 - that is to say the face of the seal 15 opposite the transverse wall 3 - is substantially flat, the exception possibly of the peripheral extreme zone of the joint 15 (without this has consequences that affect the water resistance).

The projections 17 having an axial height less than the thickness of the seal 15, they do not protrude outside the joint 15, but remain embedded and contained in the inside of the seal 15. As a result, the projections 17 do not deform the face exterior of the joint 15, the latter having a good quality surface condition, to ensure a good contact with the rim of the container neck, and therefore a good seal. In addition, protrusions not exceeding the outside of 15, there is no particular constraint on their position at the level of the inner face 16 of the transverse wall 3 of the plug 1.

The method for producing the plug 1 is considerably simplified, and the dimensional requirements of the mold used considerably reduced.

The configuration of the projection 17 is such that there is a zone 27 - called zone hooking - included axially between the transverse wall 3 and the said projection 17. Part of the material deposited at the bottom of the cap and flowing against the transverse wall 3 is placed in the attachment zone 27.

Thus, in addition to the physicochemical bonding of the seal 15 cast on the face 16 of the transverse wall 3, it exists, because of the presence of protrusions 17, a mechanical attachment of said joint 15, once solidified, which prevents it from becoming detached from said transverse wall 3.

Claims (14)

1. Assembly comprising:

   a cap (1) of the type comprising an end cross wall (3) and a cylindrical skirt (4) comprising a thread (8) on its inside face (7) designed to cooperate with a complementary external thread on the neck of a receptacle;

   and a seal (15) placed in contact with the inside face (16) of the cross wall (3) of the cap (1), the seal (15) having been put into place by moulding and extending approximately over the entire inside face (16) of the said cross wall (3);

      the cross wall (3) of the cap (1) comprising at least one projection (17) on its inside face (16) forming an attachment means for the seal (15), the said projection (17) being coated and covered by the seal (15), characterised in that the seal is generally in the form of a disk with an approximately constant thickness, the axial height of the protection (17) being less than the thickness of the said seal (15).
2. Assembly according to claim 1, characterised in that the protection (17) comprises at least one face (21, 25, 27) inclined at an acute angle (β,γ) from the axis (2) of the cap (1) such that when the seal (15) is put into place in the cap (1), at least one area of the said seal (15) is included within an attachment area (27) located axially between the cross wall (3) and a part of the said projection (17).
3. Assembly according to claim 1 or 2, characterised in that the projection (17) has an axial section in the form of at least one trapezium for which the small base (19) is located towards the free end of the said projection (17), the said trapezium being such that one of the two angles (β) adjacent to the small base (19) is acute.
4. Assembly according to claim 3, characterised in that one of the two angles (β) adjacent to the small base (19) is between 40° and 80°, and particularly close to 60°.
5. Assembly according to claim 1 or 2, characterised in that projection (17) is in the shape of at least one trapezium in an axial section, for which the large base (23) is towards the free end of the said projection (17).
6. Assembly according to claim 5, characterised in that the said trapezium has an axis of symmetry (24) approximately parallel to the axis (2) of the cap (1).
7. Assembly according to any one of claims 1 to 6, characterised in that the projection (17) is annular, the axis of the said projection (17) being approximately coincident with the axis (2) of the cap (1).
8. Assembly according to any one of claims 1 to 7, characterised in that it comprises two approximately concentric annular projections (17), with an axis approximately coincident with the axis (2) of the cap (1).
9. Assembly according to claim 8, characterised in that the free ends (19) of the two projections (17) are axially offset from each other.
10. Assembly according to any one of claims 1 to 9, characterised in that the axial height of the projection (17) is less than half the thickness of the cross wall of the cap.
11. Assembly according to any one of claims 1 to 10, characterised in that the axial height of the projection (17) is less than a third of the thickness of the cross wall of the cap.
12. Assembly comprising firstly a cap (1) and a seal (15) according to any one of claims 1 to 11, and secondly a receptacle neck or a receptacle with a neck, the said receptacle being empty or at least partially filled with given contents.
13. Process for making a cap (1) - seal (15) assembly according to any one of claims 1 to 11, comprising the following steps:

    a cap (1) comprising at least one projection (17) is made by moulding;

    a given volume of material forming the seal (15) is deposited in the bottom of the cap (1), in liquid or paste form, such that the material spends over the inside face (16) of the cross wall (3) of the cap (1), and coats and covers the projection (17), and is characterised in that the said volume is sufficient so that the thickness of the seal is greater than the axial height of the projection (17).
14. Process for making a cap (1) - seal (15) assembly according to claim 13, characterised in that once the material from which the seal (15) is made has been deposited in the bottom of the cap (1), the said material is compressed in contact with the cross wall (3) of the cap (1).

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