WO2002064440A1

WO2002064440A1 - Closure cap comprising means for securing a moulded joint

Info

Publication number: WO2002064440A1
Application number: PCT/FR2002/000553
Authority: WO
Inventors: Philippe Nusbaum
Original assignee: Bericap
Priority date: 2001-02-15
Filing date: 2002-02-13
Publication date: 2002-08-22
Also published as: ATE305418T1; ES2250621T3; EP1360118B1; FR2820722A1; EP1360118A1; DE60206360T2; HUP0303032A3; FR2820722B1; DE60206360D1; HUP0303032A2

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

Cap comprising means for attaching a cast joint

The invention relates to an assembly comprising a plug and a seal placed by pouring into the bottom of the plug, as well as a method for producing 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.

Such plugs are already known, in which the fitting of the seal is done by depositing a certain volume of material constituting the seal on the transverse wall, using a distributor.

The deposited material is hot, liquid or pasty, and therefore spreads over the internal face of the transverse wall. The joint is then pressed against the transverse wall using a tool. Physicochemical bonding of the poured joint then occurs on the internal face of the transverse wall.

In the prior art, the cast joint is held against the transverse wall only by this physical-chemical adhesion force.

However, the adhesion of the joint to the transverse wall is not optimal. It sometimes happens that the seal comes off from said wall, and can thus escape from the plug, in particular during storage of the plug-seal assembly and its 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 ensured.

Several solutions have been considered to solve this problem.

Document US 4,697,716 describes a plug having a groove on the internal face of 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 plug and on the other hand an annular projection.

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

However, the annular projection is placed relative to the axis of the stopper so that, once the seal has been poured into the groove, and when the stopper is screwed onto a container neck, the seal is located opposite the rim of the neck of the container.

Therefore, the projection must meet a number of criteria

- On the one hand, the projection must have a sufficiently high axial height to allow defining a groove and to contain the seal in this groove. When the cap is screwed onto the container neck, the seal is compressed so that it locally has a thickness less than the axial height of the projection, and remains held in the groove;

on the other hand, the position of the projection must be precise. In particular, the projection must not have a too small diameter, this being able to harm a good maintenance of the joint in the groove. Conversely, the projection should not have too large a diameter, because it would risk in this case being located opposite the rim of the container neck, which would affect the seal. In addition, given the axial height of the projection, screwing the plug onto the neck could damage the projection.

Thus, in document US 4,697,716, the projection is used both for attaching the seal and for sealing the plug. As a result, the dimensional characteristics of the projection must be precise, the molding of the plug being consequently made more complex. Document GB 1 224 669 describes a stopper 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 stopper.

A seal is poured into the bottom of the plug and then die, so as to match the shape of the internal face of the transverse wall and the projection. The seal therefore has an annular boss at the level of the projection.

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

Similarly to document US 4,697,716, the manufacture of the stopper described in document GB 1,224,669 is relatively complex. In fact, the projections must be positioned and molded very precisely, since they play a fundamental role in sealing.

In addition, the stamping of the seal must also be carried out in a precise manner, the surface condition of the seal at the level of the projection having to make it possible to guarantee a good seal. This stamping therefore constitutes an additional operation generating additional cost and longer manufacturing times.

As for document GB 2 111 965, it describes a stopper, provided with sealing lips intended to cooperate with the rim of a container neck. When the stopper is placed on the neck, the lips are bent and applied against this rim, so as to ensure the seal. In order to ensure good sealing, despite the rigidity of the lips, document GB 2 111 965 provides for coating the lips with a thin film of a more flexible material making it possible to improve the contact between the lips and the rim. of the cervix.

The flexible material covers the lips, forming a ring at the bottom of the stopper. The ring has a curved surface or a shape that perfectly matches the shape of the projections. However, the objective of document GB 2 111 965 is to improve the sealing of the plugs provided with sealing lips but devoid of seal. It does not offer an effective solution to the problem of catching a cast joint 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 plug - associated with a cast joint - in which the functions of attachment of the joint and sealing are dissociated.

To this end, 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 pouring and extending substantially over the entire internal face of said transverse wall.

According to a general definition of the invention, the transverse wall of the stopper comprises, on its internal face, at least one projection forming a hooking means for the seal, said projection being coated and covered by the seal, the seal having the shape general of a disc of substantially constant thickness, and the axial height of the projection being less than the thickness of said seal.

This in particular makes it possible to overcome the constraints of precise positioning of the attachment projections, and therefore to produce a plug according to a simpler and less restrictive process.

According to the invention, the projection comprises at least one face inclined at an acute angle relative to the axis of the stopper so that, when the seal is placed in the stopper, at least one area of said seal is included in a attachment zone located axially between the transverse wall and part of 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 said projection, said trapezium being such that one of the two adjacent angles at 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 of at least one trapezium whose large base is located towards the free end of said projection. For example, said trapezium has an axis of symmetry substantially parallel to the axis of the plug.

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

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

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

According to a second aspect, the invention relates to an assembly on the one hand a plug and a seal, as previously described, and on the other hand a container neck or a container having a neck, the said container being empty or at least partially filled with certain content.

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

- A plug is produced by molding comprising at least one projection;

- a certain volume of material constituting the seal is deposited at the bottom of the cap in liquid or pasty form, so that the material spreads over the internal face of the transverse wall of the plug, coats and covers the projection.

Once the material constituting the seal deposited at the bottom of the plug, said material can be compressed against the transverse wall of the plug.

The other characteristics 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 plug 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 plug having projections according to a variant of a first embodiment;

- Figure 4 is a view of detail B of Figure 3;

- Figure 5 is a partial axial sectional view of a plug having projections according to a second embodiment;

First of all, reference is made to FIG. 1 which represents a plug 1 of axis 2, the plug 1 being for example made of plastic.

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

The cylindrical skirt 4 has, on its outer face 5, notches 6 intended to facilitate the screwing and unscrewing of the plug 1 by a user, and, on its 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 tamper-evident band 9, connected to 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 comprises hooking projections 12, directed towards the axis 2 of the stopper 1, and intended to cooperate with the neck of a container to ensure the maintenance of the tamper-evident band 9 at the neck of the said container when, during the first opening of said container, the bridges 11 are broken.

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

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

The transverse wall 3 of the plug 1 comprises, on its internal face 16, one or more protrusions 17 forming means for attaching the seal 15, thus preventing the said seal 15 from being detached from the transverse wall 3. The protrusions 17 have come from manufacturing , by molding, with the plug 1. They have a relatively small axial height, in particular less than half, or even a third, of the thickness of the transverse wall 3 of the plug 1. In addition, the width of the projections 17 in section transverse is also reduced.

The protrusions 17 are annular, of axis substantially coincident with the axis 2 of the plug 1. We will now describe, with reference to FIGS. 1 to 4, a first embodiment of the projections 17.

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 trapezoid, or rather of two trapezoids symmetrical with respect to the axis of said projection 17.

The large base 18 of the trapezoid is substantially coincident with the transverse wall 3, the small base 19 of the trapezoid constituting the free end of the projection 17. The small base 19 can be of very small length, so that the trapezium is similar to a triangle.

A first face 20 of the trapezoid, distinct from the bases 18, 19, and located opposite the axis 2 of the plug 1, is inclined relative to the transverse wall 3 by an obtuse angle α, for example between 130 ° and 170 °, especially around 150 °. A second face 21 of the trapezoid, 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 trapezoid is rounded.

According to a first variant of this first embodiment, illustrated in FIGS. 1 and 2, the transverse wall 3 of the plug 1 comprises three annular projections 17, substantially concentric, with an axis substantially coincident 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 in FIG. 3, the transverse wall 3 of the plug 1 comprises three projections 17 annular, substantially concentric, axis substantially coincident 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. An additional projection 17 is disposed towards the periphery of the transverse wall 3.

A second embodiment of the projections 17 will now be described, with reference to FIG. 5.

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

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

The establishment of the seal 15 is done by depositing a certain volume of material at the bottom of said plug 1. This deposition can be carried out using an extruder or a "hot melt" gun.

The constituent material of the seal 15, hot and liquid, or at least pasty, spreads over the internal face 16 of the transverse wall 3, flows to the projections 17, coats and covers them.

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

The joint can then be pressed against the transverse wall using a tool, leaving an imprint on the joint 15 as illustrated in FIG. 2. The volume of material deposited is sufficient for the thickness of the seal 15 to be greater than 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 with which the cap 1 is intended to be associated, in order to guarantee a very good seal. In addition, the stamping allows the projections 17 to penetrate well into the material constituting the seal 15.

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

With or without stamping, the outer face of the seal 15 - that is to say the face of the seal 15 opposite the transverse wall 3 - is substantially planar, with the possible exception of the end peripheral zone of the seal 15 (without that this has consequences affecting the sealing).

The projections 17 having an axial height less than the thickness of the seal 15, they do not protrude outside the seal 15, but remain coated and contained inside the seal 15. As a result, the projections 17 do not deform not the outer face of the seal 15, the latter having a good quality surface condition, making it possible to guarantee good contact with the rim of the container neck, and therefore good sealing. In addition, since the projections do not protrude outside the seal 15, there is no particular constraint on their position at the level of the interior face 16 of the transverse wall 3 of the plug 1.

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

The configuration of the projection 17 is such that there is a zone 27 - called attachment zone - axially comprised between the transverse wall 3 and said projection 17. Part of the material deposited at the bottom of the plug and flowing against the transverse wall 3 is placed in the attachment zone 27. Thus, in addition to the physicochemical bonding of the joint 15 cast on the internal face 16 of the transverse wall 3, there exists, due to the presence of the projections 17, a mechanical attachment of said joint 15, once solidified, which l 'prevents separation from said transverse wall 3.

Claims

1. Set including:

- A plug (1) of the type comprising a transverse end wall (3) and a cylindrical skirt (4) comprising, on its internal face (7), a thread (8) intended to cooperate with an external complementary thread of a container neck;

- And a seal (15) placed against the internal face (16) of the transverse wall (3) of the plug (1), the seal (15) having been put in place by pouring and extending substantially over the entire internal face (16) of said transverse wall (3); the transverse wall (3) of the plug (1) comprising, on its internal face (16), at least one projection (17) forming attachment means for the seal (15), the said projection (17) being coated and covered by the seal (15), characterized in that the seal has the general shape of a disc of substantially constant thickness, the axial height of the projection (17) being less than the thickness of said seal (15).

2. Assembly according to claim 1, characterized in that the projection (17) comprises at least one face (21, 25, 27) inclined at an acute angle (β, γ) relative to the axis (2) of the plug (1) so that, when the seal (15) is placed in the plug (1), at least one zone of said seal (15) is included in a hooking zone (27) located, axially, between the transverse wall (3) and part of said projection (17).

3. An assembly according to claim 1 or 2, characterized in that the projection (17) has, in axial section, the shape of at least one trapezium whose small base (19) is located towards the free end of said projection (17), said trapezium being such that one of the two angles (β) adjacent to the small base (19) is acute.

4. An assembly according to claim 3, characterized in that one of the two angles (β) adjacent to the small base (19) is between 40 ° and 80 °, in particular close to 60 °.

5. The assembly of claim 1 or 2, characterized in that the projection (17) has, in axial section, the shape of at least one trapezium whose large base (23) is located towards the free end of said projection (17).

6. An assembly according to claim 5, characterized in that said trapezium has an axis of symmetry (24) substantially parallel to the axis (2) of the plug (1).

7. An assembly according to any one of claims 1 to 6, characterized in that the projection (17) is annular, the axis of said projection (17) being substantially coincident with the axis (2) of the plug (1 ).

8. An assembly according to any one of claims 1 to 7, characterized in that it comprises two substantially concentric annular projections (17), of axis substantially coincident with the axis (2) of the plug (1).

9. An assembly according to claim 8, characterized in that the free ends (19) of the two projections (17) are offset axially with respect to each other.

10. An assembly according to any one of claims 1 to 9, characterized in that the projection (17) has an axial height less than half the thickness of the transverse wall of the plug.

11. An assembly according to any one of claims 1 to 10, characterized in that the projection (17) has an axial height less than a third of the thickness of the transverse wall of the plug.

12. An assembly comprising on the one hand a plug (1) and a seal (15) according to any one of claims 1 to 11, and on the other hand a container neck or a container having a neck, said container being empty or at least partially filled with a certain content.

13. Method for producing a plug (1) - seal (15) assembly according to any one of claims 1 to 11, characterized in that it comprises the following steps:

- A plug (1) is produced by molding comprising at least one projection (17);

- A certain volume of material constituting the seal (15) is deposited at the bottom of the plug (1) in liquid or pasty form, so that the material spreads over the internal face (16) of the transverse wall (3) of the plug (1), coats and covers the projection (17).

14. Method for producing a plug (1) - seal (15) assembly according to claim 13, characterized in that, once the material constituting the seal (15) deposited at the bottom of the plug (1), the said material against the transverse wall (3) of the plug (1).