WO2002051712A1

WO2002051712A1 - Closure for liquid product containers

Info

Publication number: WO2002051712A1
Application number: PCT/EP2001/015028
Authority: WO
Inventors: Alain Franchet
Original assignee: Prispa Holding S.A.
Priority date: 2000-12-22
Filing date: 2001-12-18
Publication date: 2002-07-04
Also published as: HK1064349A1; RU2264959C2; UA75903C2; ES2225058T3; BR0116748A; EP1216930B1; EP1216930A1; PT1216930E; PE20020644A1; ZA200304952B; ATE267747T1; CN1246195C; CN1482984A; DE60011112T2; DE60011112D1; MXPA03005772A; AR032029A1; TR200402130T4; DK1216930T3

Abstract

The invention concerns a closure for liquid product container comprising a lateral skirt (1) provided with an internal thread (10) and a lower tear band (11) and linked to an upper plate (2) bearing internally sealing means designed to co-operate with the upper edge (B) of the neck (C) of the container. The invention is characterised in that said sealing means comprise an outer shoulder (4) arranged in the linking zone between the skirt (1) and the plate (2), including a radial projection, and bearing an elastically deformable peripheral lip (3) extending, when inactive, downwards towards the axis (X) of the closure and designed, in position for actuating the closure element, to be interposed between the projection of said shoulder (4) and said neck (C) matching in shape, when stressed, at least part of the outer curvilinear periphery (b) of the neck upper edge (B).

Description

Cap for liquid product containers

The present invention relates to a threaded plug for a container for liquid products. The caps used in the packaging of liquid products such as drinks and, more particularly, carbonated drinks include in particular a side skirt provided with an internal thread ensuring the connection with the threaded neck of the container and connected to an upper plate carrying internally sealing means intended to cooperate with the upper edge of said neck.

In most cases, the skirt extends downwards by a tamper-evident band separable via a weakening zone engaging with an annular projection formed on the neck, below the thread. There are already plugs of the type described in the

EP 76778 where the sealing means overcomes the presence of an attached seal and are made in one piece with the plug. In this document, the sealing means comprise a rigid crown intended to be force fitted into the neck of the container. However, this fitting creates stresses even in the upper plate, which, under the action of time, heat and internal pressure, produces cracks and / or deformations detrimental both to the sealing and to the 'aesthetic.

In addition, for there to be a sufficient contact surface between the neck and the side wall of the crown, it is advisable to give the latter a significant height.

The main consequences of this configuration are, on the one hand, to impose a high tightening torque and, on the other hand, to increase the risks of violent exhaust which are generally caused by late degassing.

These risks are further accentuated by the use of a single constituent material such as polyethylene, less resistant to creep than the polypropylene used for traditional stoppers fitted with an attached seal. Another embodiment is described in EP 481 981 where the sealing means consist of a flexible lip intended to be folded back on itself and crushed by the upper edge of the neck in the closed position of the cap.

However, to obtain a satisfactory seal, it is also necessary here to exert a significant screwing torque because the lip must be folded at least 90 ° upwards on itself and / or against the plate.

In addition, the deformation of the lip is difficult to control, especially in the absence of means for centering the neck.

A variant described in WO 00/56615 consists in thinning and lengthening the flexible lip.

However, the length and fineness of this lip are then excessive to the point of making it difficult to perfect the mold as well as mastering the manufacturing process and in particular the cooling phase, which results in a slower production rate.

In addition, this variant aims to fill the entire upper edge of the container neck with a single lip.

However, this variant does not make it possible to obtain an optimal level of tightness because it is not possible to control the stresses of deformation of the lip over such a long length, without having wedging means on the wall. internal plug.

The present invention aims to solve these technical problems satisfactorily.

This object is achieved, in accordance with the invention, by means of a threaded plug of the preceding type, characterized in that said sealing means comprise an external shoulder formed in the connection zone between the skirt and the plate, having a radial projection and carrying an elastically deformable peripheral lip extending, at rest, downwards towards the axis of the stopper and intended, in the closed position of the stopper, to be inserted between the projection of said shoulder and the neck in marrying, under constraints, at least part of the curvilinear outer periphery of the upper edge of the neck.

According to a first embodiment, said sealing means further comprise an elastically deformable inner annular lip positioned so that its end free wife under constraints, at least the inner periphery of the upper edge of the neck in the closed position of the cap.

Alternatively, said inner lip is formed or carried by an independent annular element disposed in the plug. According to another variant, said inner lip has a diameter for connection to the plate between the outside and inside diameters of said neck and is inclined with respect to the axis of the stopper at an angle between 0 and 45 °.

According to an advantageous characteristic, said inner lip is intended to be inserted under stresses, in the closed position of the stopper, on the one hand an inner shoulder secured to the underside of the plate and on the other hand the neck of the container.

According to another characteristic, the face of the outer shoulder and / or of the inner shoulder, located opposite the neck in the closed position of the plug, has an undercut.

According to yet another characteristic, said plate is provided at its center with a set of radial stiffening ribs. If necessary, these ribs are attached to the inner shoulder.

According to a second alternative embodiment, said sealing means comprise, in addition, a centering and locking ring integral with the plate extending coaxially opposite said peripheral lip, delimiting, with said external shoulder and / or the peripheral lip, a groove in which the neck is housed, in the closed position of the stopper. According to another advantageous characteristic, the radially outer face of said crown is provided, in the lower part, with a boss intended to bear against the internal lateral wall of the neck.

According to yet another characteristic, the height of the portion of the crown projecting inside the neck in the closed position of the cap is greater than the dead unscrewing stroke prior to the separation of the tamper-evident band.

According to an advantageous characteristic, said peripheral lip is connected to the underside of the outer shoulder. According to yet another characteristic, said peripheral lip comprises a first rectilinear section, connected by a end of said external shoulder, and extended at its other end via an elbow by a second straight section.

Preferably, the elbow defines an angle between the two sections of the lip, the value of which is between 0 and 60 °. In addition, said peripheral lip or its first section is inclined at an angle between 20 ° and 60 ° relative to the axis of the plug.

According to yet another characteristic, the thickness of said peripheral lip as well as the geometry of the outer shoulder are determined, so that the bearing contact between said lip and the upper edge of the neck is made above the planes seal of said neck, which guarantees a good seal.

According to a specific variant, the lower face is provided with a rod extending in the direction of the inner lip. The invention makes it possible to ensure a reinforced tightness of the container by means of a monobloc and single-material stopper, capable of being produced in a single molding operation (injection or compression), and offering relatively low screwing and unscrewing torques. and regular. The cooperation of the flexible lips (peripheral and / or interior), with the corresponding shoulders, makes it possible to optimize their deformation and their positioning relative to the edges of the neck.

The invention will be better understood on reading the description which will follow with reference to the accompanying drawings, in which: - Figures 1A, 2A, 3A and 4A show sectional views of four embodiments of the plug of the invention, in the free state before closing the container;

- Figures 1B and 1C show partial sectional views of the embodiment of Figure 1A respectively in the semi-closed position on the neck, and in the sealed closure position of the container;

- Figures 1D and 1E show partial sectional views of two alternative embodiments.

- Figures 2B and 2C show partial sectional views of the embodiment of Figure 2A, respectively in the semi-closed position on the neck and sealed; - Figures 3B and 3C show partial sectional views of the embodiment of Figure 3A, respectively in the semi-closed position on the neck, and sealed.

- Figures 4B and 4C show partial sectional views of the embodiment of Figure 4A, respectively in the semi-closed and sealed position

The stopper shown in the figures is intended for plugging containers of liquid products, such as drinks (mineral water, fruit juice, sodas, etc.). These containers can be made of glass or plastic, by blowing air into preforms.

Generally, this plug comprises a side skirt 1 provided with an internal thread 10 and connected to an upper plate 2.

The geometry and, in particular, the pitch of the thread 10, are adapted to the threads F of the neck C of the container. The skirt 1 is extended downwards by a tamper-evident band 11 via a weakening zone 12 capable of being broken by unscrewing the plug.

The upper plate 2 of the plug internally carries sealing means intended to cooperate with the upper part of the neck C and in particular its upper edge B. The section of the upper edge B is delimited laterally by an outer curvilinear periphery b (called "drinking"). ) and by a generally curvilinear inner circumference.

In the context of the invention, the sealing means are made in one piece with the skirt 1 and the plate 2, and using the same plastic, which is preferably polyethylene.

In the embodiment of FIGS. 1A to 1C, these sealing means comprise a radially outer shoulder 4, formed in the connection zone between the skirt 1 and the plate 2, having a radial projection 41 and carrying a peripheral lip 3, elastically deformable which extends, at rest, as shown in Figure 1 A, downward towards the axis X of the plug.

The lip 3 is thus placed across the upward stroke of the upper edge B of the neck C when the cap is screwed onto the container. In the semi-closed position of FIG. 1B, the edge B of the neck C comes into contact with the lip 3. Continued screwing results in the progressive deformation of the lip 3 by the edge B until the lip 3 marries, under stress, at least part of the curvilinear outer periphery b of the edge B, being inserted and crushed in space. comprised between the shoulder 4 and the said neck as shown in FIG. 1C while leaning against the projection 41.

The face of the shoulder 4 facing the neck C preferably has, above the projection 41, an undercut 40 making it possible to compensate for possible centering defects, dimensional differences in expansion, in making the neck and / or the plug.

However, in order to distribute the deformation stresses regularly along the lip 3, the face 40 of the shoulder 4 and / or of the plate 2 located opposite the neck C may have, according to a variant shown in FIGS. 3A at 3C, a profile complementary to that of edge B.

In the embodiment of FIG. 1D, the lip 3 comprises a first straight section 31, connected by one end to the underside of the shoulder 4, and extended at its other end, via an elbow 30, to a second section straight 32. The elbow 30 defines an angle α between the two sections 31, 32 whose value is positive or negative and between 0 and 60 °, on one side or the other of the axis of the first section 31.

The lip 3 (and here the first section 31) is inclined with an angle β between 20 ° and 60 ° relative to the axis X of the plug. This geometry ensures the shaping of the peripheral lip 3 on the upper edge B of the neck in the closed position, as illustrated in FIG. 1 C.

More generally, the profile and the thickness (between 0.2 and 0.6 mm) of the lip 3 as well as the geometry of the shoulder 4 and in particular of the projection 41 are determined so that the lip 3 conforms to at least part of the periphery b of the edge B in a sealed manner, above the joint planes of the neck (not shown), covering, where appropriate, the adjacent lower part of the curved periphery b.

These joint surfaces are made up of fine vertical ribs resulting from the container manufacturing operations. Indeed, the molding of the container of its preform, and in particular of the neck C, can be carried out at by means of a mold formed of two separable shells delimiting, between their edges in contact, a very narrow gap where the plastic can creep and form parasitic ribs. These ribs remain on the container neck after it has been finished. A good seal can therefore only be ensured when the lip 3 is in abutment against a smooth surface of the neck C, that is to say devoid of any roughness, which is found only above the joint planes.

In the variant of FIG. 1E, the peripheral lip 3 is associated with a crown 5 for centering and / or blocking carried by the lower wall of the plate 2. The lowest point of the crown 5 is located above the level from the free end of the lip 3 at rest, in its position before closing as shown in FIG. 1A. Preferably, the plate 2 is provided, in its center, with a set of radial stiffening ribs 7 leaning here against the crown 5.

In the embodiment of Figures 2A to 2C, the sealing means are provided with an inner annular lip 6, elastically deformable.

This annular lip 6 is here integral with the plate 2 and is inclined towards the axis X of the plug, at an angle γ between 0 and 45 ° with a diameter of connection to the plate 2 between the outside and inside diameters of the neck C.

Thus, its free end is capable of fitting, under constraints, the curvilinear inner periphery b ′ of the upper edge B of the neck C, in the closed position of the cap, so as to provide a seal complementary to that provided with the outer periphery b from edge B by the peripheral lip 3.

In this position shown in Figure 2C, the inner lip 6 is interposed and crushed, under stress, between a radial projection 51 carried by an inner shoulder 52 secured to the underside of the plate 2 and the upper edge B of the neck, as the peripheral lip 3 between the outer shoulder 4 and the edge B.

According to a variant not shown, the lip 6 is carried or constituted by an independent element, in the form of a ring or disc which is arranged in the bottom of the stopper. The face of the shoulder 52 turned opposite the neck C has here, above the projection 51, an undercut 50 whose function is similar to that of the undercut 40 of the shoulder 4.

In the embodiment of FIGS. 3A to 3C, the crown 5 is extended downwards and is intended to extend coaxially to the neck C, facing the lip 3.

The crown 5 defines, with the outer shoulder 4 and the lip 3, a groove 20, in which is housed the upper edge B of the neck C in the closed position so as to provide centering and a complementary seal inside col C.

The underside of the plate is provided with a rod 21 extending in the groove 20 in the direction of the lip 3. The rod 21 ensures the location and the concentration of the support forces of the neck C, transmitted by the lip 3, on a circular line of the plate 2. Although shown only in FIGS. 3B and 3C, the rod 21 can be used in association with the embodiments of the other figures.

The radially outer face of the crown 5 is provided, in its lower part, with a boss 53. The boss 53 bears against the internal lateral wall of the neck C in the semi-closed (FIG. 3B) and closed (FIG. 3C), which causes the lower part of the crown 5 to pivot towards the inside of the neck.

The movement of the crown 5 and the contact of the boss 53 against the internal wall of the neck C make it possible to offer a second sealing zone complementary to that situated on the outer periphery b of the edge B.

In the embodiment of FIGS. 4A to 4C, the height of the portion of the crown 5 projecting inside the neck C, in the closed position of the cap, is greater than the dead unscrewing stroke prior to separation of the tamper-evident band 11 by rupture of the embrittlement zone 12.

Under these conditions, the upper edge B of the neck C meets the end of the crown 5 first, during its upward movement, and leaves this crown last, during its descent. This arrangement thus makes it possible to maintain the seal and avoid any untimely degassing and / or any venting detrimental to the quality of the liquid product, even in the event of accidental or fraudulent partial unscrewing which does not lead to rupture. of the embrittlement zone 12.

The internal wall of the neck is always protected from external aggressions likely to occur, during the operations of manufacture, transfer and bulk storage of the containers and / or preforms, unlike the external wall, in particular in the case of returnable containers.

It follows that the state of the internal surfaces of the neck, coming into contact with the inner lip 6 and / or the boss 53, participates according to the invention, thanks to the favorable synergy of the various sealing means, in obtaining very high level of airtightness, whatever the conditions of use.

Claims

1. Cap for container of liquid products of the type comprising a side skirt (1) provided on the one hand, with an internal thread (10) and a lower tamper-evident band (11) and connected on the other hand, to an upper plate (2) internally carrying sealing means intended to cooperate with the upper edge (B) of the neck (C) of the container, characterized in that said sealing means comprise an external shoulder (4) formed in the connection zone between the skirt (1) and the plate (2), having a radial projection, and carrying an elastically deformable peripheral lip (3) extending, at rest, downwards in the direction of the axis (X) of the stopper and intended, in the closed position of the stopper, to be interposed between the projection of said shoulder (4) and said neck C by marrying, under constraints, at least part of the curvilinear outer periphery (b) of the upper edge (B ) of the cervix.

2. Plug according to claim 1, characterized in that said sealing means further comprise an elastically deformable inner annular lip (6) positioned so that its free end conforms, at least to the inner circumference ( b ') of the upper edge (B) of the neck in the closed position of the plug.

3. Plug according to claim 2, characterized in that said inner lip (6) is formed or carried by an independent annular element disposed in the plug.

4. Cap according to claim 2, characterized in that said inner lip (6) has a diameter of connection to the plate (2) between the outside and inside diameters of said neck (C) and is inclined relative to the axis of the plug with an angle (γ) between 0 and 45 °.

5. Stopper according to one of claims 2, 3 or 4, characterized in that said inner lip (6) is intended to be inserted, under stress, in the closed position of the stopper, between, on the one hand, a inner shoulder (52) integral with the underside of the plate (2) and, on the other hand, the neck (C) of the container.

6. Stopper according to claim 1 or 5, characterized in that the face of the outer shoulder (4) and / or of the inner shoulder (52), located opposite the neck (C) in the closed position of the cap, has an undercut (40, 50)

7. Cap according to one of the preceding claims, characterized in that said plate (2) is provided in its center with a set of radial ribs (7) for stiffening.

8. Stopper according to one of the preceding claims, characterized in that said sealing means comprise, in addition, a centering and / or locking ring (5) integral with the plate (2) and extending coaxially opposite said peripheral lip (3), delimiting with said external shoulder (4) and / or the lip (3) a groove (20) in which the neck (C) is housed, in the closed position of the stopper.

9. Cap according to claim 8, characterized in that the radially outer face of said crown (5) is provided in the lower part, with a boss (53) intended to bear against the internal lateral wall of the neck (C).

10. Cap according to claim 8 or 9, characterized in that the height of the portion of the crown (5) projecting inside the neck in the closed position of the cap is greater than the dead travel of the unscrewing prior to the separation of the tamper-evident band (11).

11. Plug according to one of the preceding claims, characterized in that said peripheral lip (3) is connected to the underside of the outer shoulder (4).

12. Cap according to one of the preceding claims, characterized in that said peripheral lip (3) comprises a first rectilinear section (31) connected by one end to said external shoulder (4) and extended at its other end via an elbow (30 ) by a second rectilinear section (32).

13. Plug according to claim 12, characterized in that the elbow (30) defines an angle (α) between the two sections (31, 32) whose value is between 0 and 60 °.

14. Plug according to one of the preceding claims, characterized in that said peripheral lip (3) or its first section (31) is inclined with an angle (β) between 20 ° and 60 ° relative to the axis ( X) of the plug.

15. Plug according to any one of the preceding claims, characterized in that the thickness of said peripheral lip (3) as well as the geometry of the outer shoulder (4) are determined, so that the contact support between said lip (3) and the upper edge (B) of the neck is made above the joint surfaces of said neck.

16. Plug according to one of the preceding claims, characterized in that the lower face of the plate (2) is provided with a rod (21) extending in the direction of the inner lip (3).