ZA200304952B

ZA200304952B - Closure for liquid product containers.

Info

Publication number: ZA200304952B
Application number: ZA200304952A
Authority: ZA
Inventors: Alain Franchet
Original assignee: Prispa Holding Sa
Priority date: 2000-12-22
Filing date: 2003-06-25
Publication date: 2004-08-25
Also published as: UA75903C2; PE20020644A1; BR0116748A; TR200402130T4; HK1064349A1; PT1216930E; DE60011112T2; DE60011112D1; RU2264959C2; ES2225058T3; MXPA03005772A; EP1216930A1; DK1216930T3; AR032029A1; ATE267747T1; CN1246195C; CN1482984A; EP1216930B1; WO2002051712A1

Description

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C WO 02/051712 PCT/EP01/15028

Stopper for liquid product containers

The present invention relates to a threaded stopper for a liquid product container.

The stoppers used in packaging liquid products such as drinks and, more particularly, carbonated drinks in particular comprise a lateral skirt provided with an internal thread providing the connection with the threaded neck of the container and connected to an upper plate internally bearing sealing means designed to cooperate with the upper edge of said neck.

In most cases, the skirt extends downward by means of a tear strip which can be separated via a region of weakness engaging with an annular projection made on the neck, below the thread.

There are already stoppers of the type described in

EP 76778 where the sealing means eliminate the need for an attached seal and are made as a single piece with the stopper. In this document, the sealing means comprise a rigid ring designed to be force-fitted into the neck of the container. However, this fitting creates stresses up to the upper plate, which over time, and under the action of heat and the internal pressure, produces cracks and/or deformations detrimental both to the sealing and to the esthetic appearance.

Furthermore, for there to be a sufficient contact area between the neck and the lateral wall of the ring, it is appropriate to give the latter considerable height.

The main consequences of this configuration are, on the one hand, of requiring a high screwing torque and, on the other hand, of increasing the risks of violent release which are generally caused by late degassing.

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In addition, these risks are enhanced by the use of a single constituent material such as polyethylene, which is less resistant to plastic flow than the polypropylene used for the conventional stoppers equipped with an attached seal.

Another embodiment is described in EP 481 981 where the sealing means consist of a flexible lip designed to be folded over itself and crushed by the upper edge of the neck in the closed position of the stopper.

However, in order to obtain satisfactory sealing, in this case it is also necessary to exert a considerable screwing torque because the lip must be folded by at least 90° upward over itself and/or against the plate.

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

A variant described in WO 00/56615 consists in making the flexible lip thinner and longer.

However, the length and thinness of this lip are then excessive to the point of making it difficult to optimize the mold and control the manufacturing method, and particularly the cooling phase, which leads to a slowdown in the production rate.

Furthermore, the subject of this variant is to cover the entire upper edge of the neck of the container with a single lip.

However, this variant does not make it possible to obtain optimum sealing because it is not possible to control the deformation stresses of the lip over such a great length, without having wedging means on the inner wall of the stopper.

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The aim of the present invention is to solve these technical problems in a satisfactory manner.

This aim is achieved, according to the invention, by means of a threaded stopper of the aforementioned type, characterized in that said sealing means comprise an outer shoulder made in the region of connection between the skirt and the plate, having a radial projection, and bearing an elastically deformable peripheral 1lip extending, at rest, downward in the direction of 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, thereby N closely following, when stressed, at least part of the outer curvilinear perimeter 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 free end closely follows, when stressed, at least the inner perimeter of the upper edge of the neck in the closed position of the stopper.

According to a variant, said inner lip consists of or is borne by an independent annular element placed in the stopper. .

According to another variant, said inner lip has a diameter of connection to the plate which is between the outer and inner diameters of said neck and is inclined with respect to the axis of the stopper by an angle of between 0 and 45°.

According to one advantageous characteristic, said inner lip is designed to be inserted, when stressed, in the closed position of the stopper, between, on the one hand, an inner shoulder secured to the lower face 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 facing the neck in the closed position of the stopper, has an undercut.

According to yet another characteristic, said plate is provided in its center with a set of radial stiffening ribs. Where appropriate, these ribs lean against the inner shoulder.

According to a second variant embodiment, said sealing means comprise, in addition, a centering and locking ring secured to the plate and extending coaxially opposite said peripheral 1lip, thereby defining, with said outer 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 ring is provided in the lower part with a boss designed to press against the inner lateral wall of the neck.

According to yet another characteristic, the height of the portion of the ring projecting inside the neck in the closed position of the stopper is greater than the dead travel of unscrewing prior to separating the tear strip.

According to one advantageous characteristic, said peripheral lip is connected to the lower face of the outer shoulder.

According to yet another characteristic, said peripheral lip comprises a first straight portion connected by one end to said outer shoulder and extended at its other end via a bend by a second straight portion.

Preferably, the bend defines an angle between the two portions of the lip, the value of which is between 0 and 60°,

Furthermore, said peripheral lip or its first portion is inclined with an angle of between 20° and 60° to the axis of the stopper.

According to yet another characteristic, the thickness of said peripheral lip and 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 mating planes of said neck, and this guarantees effective sealing.

According to a specific variant, the lower face is provided with a retaining ring extending in the direction of the inner lip.

The invention makes it possible to provide enhanced sealing of the container by means of a single-piece and single-material stopper, capable of being produced in a single molding operation (injection or compression molding), and offering relatively low and uniform screwing and unscrewing torques.

The cooperation of the (peripheral and/or inner) flexible lips with the corresponding shoulders makes it possible to optimize their deformation and their position relative to the rims of the neck.

The invention will be better understood on reading the following description with reference to the appended drawings, in which:

_ m6 ~ figures 1A, 2A, 3A and 4A show sectional views of four embodiments of the stopper of the invention, in the free state before closure of the container; : - figures 1B and 1C show partial sectional views of the embodiment of figure 1A respectively in the half-closed position on the neck and in the sealed closure position of the container; - figures 1D and 1E show partial sectional views of two variant embodiments, - figures 2B and 2C show partial sectional views of the embodiment of figure 2A, respectively in the half-closed position on the neck and in the sealed closure position; - figures 3B and 3C show partial sectional views of the embodiment of figure 3A respectively in the half-closed position on the neck and in the sealed "closure position, - figures 4B and 4C show partial sectional views of the embodiment of figure 4A respectively in the half-closed position and in the sealed closure position. .

The stopper shown in the figures is designed for stoppering liquid product containers, such as drinks (mineral waters, fruit juices, sodas, etc.). These containers may be made from glass or plastic, by blowing air into preforms.

In general, this stopper comprises a lateral 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 matched to the threads F of the neck C of the container. The skirt 1 is extended downward by a tear strip 11 via a region of weakness 12 capable of being broken by unscrewing the stopper.

The upper plate 2 of the stopper has, internally, sealing means designed to cooperate with the upper part of the neck C and especially its upper edge B.

The section of the upper edge B is delimited laterally by an outer curvilinear perimeter b called the "drinking edge" and by a generally curvilinear inner perimeter b'.

In the context of the invention, the sealing means are made as a single piece with the skirt 1 and the plate 2, and by using the same plastic material, which is preferably polyethylene.

In the embodiment of figures 1A to 1C, these sealing means comprise a radially outer shoulder 4 made in the region of connection between the skirt 1 and the plate 2, having a radial projection 41, and bearing an elastically deformable peripheral lip 3 which extends, at rest, as shown in figure 1A, downward in the direction of the axis X of the stopper.

The lip 3 is thus placed through the rising travel of the upper edge B of the neck C when screwing the stopper onto the container.

In the half-closed position of figure 1B, the edge B of the neck C comes into contact with the lip 3.

The continuation of screwing leads to the gradual deformation of the lip 3 by the edge B until the lip 3 closely follows, when stressed, at least part of the outer curvilinear perimeter b of the edge B, thereby being inserted and crushed in the space between the shoulder 4 and said neck, as shown in figure 1C, while leaning against the projection 41.

That face of the shoulder 4 which is turned toward the neck C preferably has, above the projection 41, an

C - 8 - undercut 40 making it possible to compensate for any centering defects or dimensional expansion gaps from producing the neck and/or the stopper.

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

In the embodiment of figure 1D, the lip 3 comprises a first straight portion 31, connected by one end to the lower face of the shoulder 4, and extended at its other end, via a bend 30, by a second straight portion 32.

The bend 30 defines an angle o between the two portions 31, 32, the value of which is positive or negative and between 0 and 60°, on one or other side of the axis of the first portion 31.

The lip 3 (and in this case the first portion 31) is inclined with an angle PB of between 20° and 60° to the axis X of the stopper.

This geometry makes it possible to ensure that the peripheral lip 3 is shaped to the upper edge B of the neck in the «closed position, as illustrated in figure 1C.

More generally, the profile and thickness (between 0.2 and 0.6 mm) of the lip 3 and the geometry of the shoulder 4 and especially of the projection 41 are determined so that the lip 3 closely follows at least part of the perimeter b of the edge B in a sealed manner, above the mating planes of the neck (not shown), thereby covering, as required, the lower part adjacent to the curvilinear perimeter b.

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These mating planes consist of thin vertical ribs resulting from the operations of manufacturing the container. This is because the molding of the container from its preform, and especially of the neck C, may be carried out by means of a mold formed from two separable shells defining, between their edges in contact, a very narrow interstice where the plastic material may flow and form parasitic ribs. These ribs remain on the neck of the container after it is finished.

Effective sealing can therefore only be ensured when the lip 3 bears against a smooth surface of the neck C, that is to say a surface free from any roughness, which is only found above the mating planes.

In the variant of figure 1E, the peripheral lip 3 is combined with a centering and/or locking ring 5 borne by the lower wall of the plate 2. The lowest point of the ring 5 is located above the free end of the lip 3 at rest, in its position before closure, as shown in figure 1A. Preferably, the plate 2 is provided, in its center, with a set of radial stiffening ribs 7, here leaning against the ring 5.

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

Here, this annular lip 6 is secured to the plate 2 and is inclined toward the axis X of the stopper, at an angle y of between 0 and 45°, with a diameter of connection to the plate 2 which is between the outer and inner diameters of the neck C.

Thus, its free end is capable of closely following, when stressed, the curvilinear inner perimeter b' of the upper edge B of the neck C, in the closed position of the stopper, so as to provide sealing which is

C - 10 - complementary to that provided with the outer perimeter b of the edge B by the peripheral lip 3.

In this position shown in figure 2C, the inner lip 6 is inserted and crushed, when stressed, between a radial projection 51 borne by an inner shoulder 52 secured to the lower face of the plate 2 and the upper edge B of the neck, just like the peripheral lip 3 between the outer shoulder 4 and the edge B.

According to a variant (not shown), the lip 6 is borne by or consists of an independent element, in the form of a ring or disk which is placed in the closed end of the stopper.

That face of the shoulder 52 which is turned facing the neck C in this case has, above the projection 51, an undercut 50, the function of which is similar to that of the undercut 40 of the shoulder 4.

In the embodiment of figures 3A to 3C, the ring 5 is extended downward and is designed to lie coaxially with the neck C, facing the lip 3. :

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

The lower face of the plate is provided with a retaining ring 21 lying in the groove 20 in the direction of the lip 3. The retaining ring 21 localizes and concentrates the bearing forces of the neck C, transmitted by the lip 3, over a circular line of the plate 2.

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Although shown solely in figures 3B and 3C, the retaining ring 21 may be used in combination with the embodiments of the other figures.

The radially external face of the ring 5 is provided, in its lower part, with a boss 53.

The boss 53 presses against the inner lateral wall of the neck C in the half-closed position (figure 3B) and in the closed position (figure 3C), which causes the lower part of the ring 5 to pivot toward the inside of the neck.

The clearance of the ring 5 and the contact of the boss 53 against the inner wall of the neck C make it possible to offer a second sealing region complementary to that located on the outer perimeter b of the edge B.

In the embodiment of figures 4A to 4C, the height of the portion of the ring 5 projecting inside the neck C, in the closed position of the stopper, is greater than the dead travel of unscrewing prior to separation of the tear strip 11 by breaking the region of weakness 12.

Under these conditions, the upper edge B of the neck C initially encounters the end of the ring 5 as it moves upward and finally leaves this ring as it moves downward.

This arrangement thus makes it possible to preserve the sealing and to prevent any inopportune degassing and/or any escape to the atmosphere which is detrimental to the quality of the liquid product, even in the case of accidental or fraudulent partial unscrewing not leading to breakage of the region of weakness 12.

To The inner wall of the neck is always protected from the external damage likely to occur during the operations of manufacture, transfer and loose storage of the containers and/or of the preforms, unlike the outer wall, in particular for returnable containers.

The result of this is that the state of the inner surfaces of the neck, coming into contact with the inner lip 6 and/or the boss 53, is involved according to the invention, due to the favorable synergy of the various sealing means, in obtaining a very high level of sealing, whatever the conditions of use.

Claims

® WO 02/051712 PCT/EP01/15028 CLAIMS

1. A stopper for a liquid product container of the type comprising a lateral skirt (1) provided, on the one hand, with an internal thread (10) and a lower tear strip (11) and connected, on the other hand, to an upper plate (2) internally bearing sealing means designed to cooperate with the upper edge (B) of the neck (C) of the container, characterized in that said sealing means comprise an outer shoulder (4) made in the region of connection between the skirt (1) and the plate (2), having a radial projection, and bearing an elastically deformable peripheral lip (3) extending, at rest, downward in the direction of the axis (X) of the stopper and intended, in the closed position of the stopper, to be inserted between the projection of said shoulder (4) and said neck C, thereby closely following, when stressed, at least part of the outer curvilinear perimeter (b) of the upper edge (B) of the neck.

2. The stopper as claimed in claim 1, characterized in that said sealing means further comprise an elastically deformable inner annular lip (6) positioned so that its free end closely follows, when stressed, at least the inner perimeter (b') of the upper edge (B) of the neck in the closed position of the stopper.

3. The stopper as claimed in claim 2, characterized in that said inner lip (6) consists of or is borne by an independent annular element placed in the stopper.

4. The stopper as claimed in claim 2, characterized in that said inner lip (6) has a diameter of connection to the plate (2) which is between the outer and inner diameters of said neck (C) and is inclined with respect to the axis of the stopper by an angle (y) of between 0 and 45°.

5. The stopper as claimed in one of claims 2, 3 or 4, characterized in that said inner lip (6) is designed to be inserted, when stressed, in the closed position of the stopper, between, on the one hand, an inner shoulder (52) secured to the lower face of the plate (2) and, on the other hand, the neck (C) of the container. 5 : 10 6. The stopper as claimed in <c¢laim 1 or 5, characterized in that the face of the outer shoulder (4) and/or of the inner shoulder (52), located facing the neck (C) in the closed position of the stopper, has an undercut (40, 50).

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7. The stopper as claimed in one of the preceding claims, characterized in that said plate (2) is provided in its center with a set of radial stiffening ribs (7).

8. The stopper as claimed in one of the preceding claims, characterized in that said sealing means comprise, in addition, a centering and/or locking ring (5) secured to the plate (2) and extending coaxially opposite said peripheral lip (3), thereby defining, with said outer 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. The stopper as claimed in claim 8, characterized in that the radially outer face of said ring (5) is provided in the lower part with a boss (53) designed to press against the inner lateral wall of the neck (C).

10. The stopper as claimed in claim 8 or 9, characterized in that the height of the portion of the ring (5) projecting inside the neck in the «closed position of the stopper is greater than the dead travel of unscrewing prior to separating the tear strip (11).

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11. The stopper as claimed in one of the preceding claims, characterized in that said peripheral lip (3) is connected to the lower face of the outer shoulder

(4).

12. The stopper as claimed in one of the preceding claims, characterized in that said peripheral lip (3) comprises a first straight portion (31) connected by one end to said outer shoulder (4) and extended at its other end via a bend (30) by a second straight portion (32).

13. The stopper as claimed in claim 12, characterized in that the bend (30) defines an angle (a) between the : two portions (31, 32), the value of which is between 0 and 60°.

14. The stopper as claimed in one of the preceding claims, characterized in that said peripheral lip (3) or its first portion (31) is inclined with an angle (8) of between 20° and 60° to the axis (X) of the stopper.

15. The stopper as claimed in any one of the preceding claims, characterized in that the thickness of said peripheral lip (3) and the geometry of the outer shoulder (4) are determined so that the bearing contact between said lip (3) and the upper edge (B) of the neck is made above the mating planes of said neck.

16. The stopper as claimed in one of the preceding claims, characterized in that the lower face of the plate (2) is provided with a retaining ring (21) extending in the direction of the inner lip (3).