HK1064349B - Closure for liquid product containers - Google Patents

Description

Cap for a container for liquid products

Technical Field

The present invention relates to a threaded cap for a container for liquid products.

Background

Cap for use in the packaging of liquid products, such as beverages, and more particularly carbonated beverages, which cap comprises in particular a side skirt having an internal thread ensuring the coupling with the threaded container neck of the container, the internal thread being coupled to an upper platform which internally supports sealing means which cooperate with the upper edge of said container neck.

In most cases the skirt extends downwardly through a non-pryable band spaced below the thread to engage an annular bead on the container neck.

For example, US 5609263 discloses a cap for a container for liquid products, comprising a side skirt having on one hand an internal thread and a lower, non-pryable band, and on the other hand connected to an upper platform having internally a sealing means cooperating with the upper edge of the neck of the container, the sealing means having an elastically deformable peripheral lip which, at rest, extends below the axis of the cap.

A lid of the type described in EP 76,778 is already present, where the sealing means is free from the reported presence of the connection and consists only of one part with the lid. In this document, the sealing means comprise a hard rim which is strongly tightly fitted on the neck of the container. However, this tight fit established limits it to the upper platform, which can lead to detrimental cracking and/or deformation, both in terms of sealing and aesthetics, under the action of time, heat generation and internal pressure.

In addition, in order to provide sufficient contact surface between the container neck and the sidewall of the hard rim, the latter is generally given a higher height.

The main consequence of such a shape is that, on the one hand, a relatively large screwing torque is necessary and, on the other hand, the risk of strong gas escape, which is generally caused by slow degassing, increases.

Furthermore, such risks are exacerbated by the use of unique structural materials such as polyethylene, which have poorer creep resistance than the polypropylene used in conventional caps equipped with the reported connectors.

Another mode of manufacture is described in EP 481981, where the sealing means consists of a flexible lip which folds back on itself and presses against the upper edge of the container neck when the lid is in the closed position.

However, since the lip should be folded at least 90 ° in height towards itself and/or towards the platform, a high screwing torque must also be applied here in order to achieve a satisfactory degree of sealing.

In addition, the deformation of this lip is particularly difficult to control without the container neck centering means.

One embodiment described in WO00/56615 involves thinning and lengthening the flexible lip.

However, the length and thickness of the lip are already excessive in order to make it easier to manufacture the mould and to control the processing, in particular the cooling period, which results in a slow production rhythm.

In addition, the purpose of this embodiment is to ensure the integrity of the upper edge of the container neck and the separate lip.

However, this embodiment does not allow to obtain an optimal level of sealing, since it is not possible to control the deformation stress of the lip if the length of the lip is long, without positioning means being mounted on the inner wall of the lid.

Disclosure of Invention

The object of the present invention is to satisfactorily solve these technical problems.

The invention provides a cap for a container for liquid products, comprising a side skirt, the skirt having on one hand an internal thread and a non-pryable band at its lower edge and on the other hand being connected to an upper platform having a sealing means therein co-acting with the upper edge of the neck of the container, the sealing device has an elastically deformable peripheral lip which, at rest, extends below the axis of the lid, wherein said sealing means further comprises an outer shoulder disposed at the region where said side skirt and upper platform are connected, the outer shoulder having a radial projection and supporting said peripheral lip for insertion between the projection of said shoulder and said container neck in the closed position of the lid, and under stress, to abut at least a portion of the curved outer periphery of the upper edge of the neck of the container.

According to a first embodiment, the sealing means further comprise an annular deformable elastic inner lip positioned such that, under stress, its free end abuts at least the inner peripheral edge of the upper edge of the neck of the container in the closed position.

According to one embodiment, said inner lip comprises or is provided with a separate annular element placed on the lid.

According to another embodiment, the diameter of the inner lip in connection with the platform is between the outer diameter and the inner diameter of the neck of the container, the inclination angle with respect to the axis of the cap being 0-45 °.

According to an advantageous feature, the inner lip is adapted to be inserted under stress between an inner shoulder fixed to the inner surface of the platform and the neck of the container when the lid is closed.

According to another feature, the surface of the external shoulder and/or of the internal shoulder placed against the neck of the container has a draft angle in the condition of closure of the lid.

According to another feature, the platform is provided with a hardened radially reinforced skirt at its central portion. If necessary, the reinforcement rests on the inner shoulder.

According to a second embodiment, the sealing means further comprise a centering and fastening ring fixed to the platform and extending coaxially with the peripheral lip, defining, with the external shoulder and/or the internal shoulder, a recess in which the neck of the container is intended to be received when the lid is in the closed condition.

According to another advantageous feature, the radially external surface of the annular rim has, in its lower part, a projection intended to rest on the internal side wall of the neck of the container.

According to another feature, the height of the raised upper skirt portion in the neck of the container when the cap is in the closed position is greater than the operating stroke of unscrewing the threads before separation of the non-pryable bands.

According to an advantageous feature, the peripheral lip is connected to the lower surface of the outer shoulder.

According to another feature, the peripheral lip comprises a first rectilinear segment connected at one end to the external shoulder and, at its other end, extending to a second rectilinear segment via an elbow portion.

The elbow portion preferably defines an included angle between the two lips, the included angle having a value of about 0-60 °.

In addition, the peripheral lip or the first section thereof has an inclination of 20 to 60 DEG with respect to the axis of the lid.

According to a further feature, the thickness of the peripheral lip and the geometry of the external shoulder are determined in such a way that the supporting contact between the lip and the upper edge of the container neck occurs above the plane of connection of the container neck, thus ensuring a good seal.

According to a particular embodiment, the lower surface is provided with a connecting element extending in the direction of the inner lip.

The invention ensures an enhanced seal of the container by means of a cap in one piece and of a single material, which can be obtained only by moulding (injection or compression) and which has a low and uniform tightening and loosening torque.

The cooperation of the flexible lips (peripheral and/or inner) and the corresponding shoulders allows their deformation and position relative to the container neck rim to be optimised.

Drawings

The invention will be better understood by reference to the following description, taken with the accompanying drawings, in which:

FIGS. 1A, 2A, 3A and 4A show cross-sections of 4 embodiments of the lid according to the invention in the free state before the closure of the container;

FIGS. 1B and 1C show the embodiment of FIG. 1A in partial section, in a semi-closed position on the neck of the container and in a closed position of the container, respectively;

FIGS. 1D and 1E show partial cross-sections of two embodiments;

FIGS. 2B and 2C show the embodiment of FIG. 2A in partial section, in a semi-closed position on the neck of the container and in a closed position, respectively;

FIGS. 3B and 3C show the embodiment of FIG. 3A in partial section, in a semi-closed position on the neck of the container and in a closed position, respectively;

FIGS. 4B and 4C show the embodiment of FIG. 4A in partial section, in a semi-closed to the neck of the container and in a closed position, respectively.

Detailed Description

The lid shown on these figures is intended to plug containers for liquid products, such as beverages (mineral water, fruit juices, sodas, etc.). These containers may be manufactured by air blow molding glass or plastic preforms.

Such caps generally comprise a side skirt 1 having internal threads 10 and an upper platform 2.

This geometry, and in particular the pitch of the thread 10, is adapted to the thread F of the neck C of the container. The skirt 1 projects downwardly past a frangible region 12 to form a non-pryable band 11 which can be broken by unscrewing the lid.

The upper deck 2 of the lid is supported from the inside on sealing means intended to cooperate with the upper part of the container neck C, in particular its upper edge B.

The section of the upper edge B is delimited laterally by a curvilinear outer perimeter B (designated as "drinking edge") and an inner perimeter that is generally curvilinear as well.

Within the scope of the invention, the sealing means are made in one piece with the skirt 1 and the upper platform 2, of the same plastic material, preferably polyethylene.

In the embodiment of figures 1A to 1C, the sealing means comprise a radially external shoulder 4, mounted at the junction of skirt 1 and platform 2, having a radial projection 41 and supporting an external peripheral lip 3 which is elastically deformable and which, at rest, as shown in figure 1A, extends towards the lower part of the axis X of the lid.

The lip 3 is positioned so that it undergoes a lifting process of the upper edge B of the neck C of the container as the cap is screwed onto the container.

In the semi-closed position of fig. 1B, the edge B of the container neck C is in contact with the lip 3.

As the cap is screwed down, the edge B gradually deforms the lip 3 until, under stress, the lip 3 and at least part of the curved outer periphery B of the edge B abut, as shown in figure 1C, being inserted and pressed against the space between the shoulder 4 and the neck of the container while resting on the projection 41.

The surface of the shoulder 4 turned against the container neck C preferably has, above the projection 41, an undercut 40 which, if necessary, makes it possible to compensate for the centering defects due to the expansion, dimensional deviations formed during the manufacture of the container neck and/or the cap.

However, in order to distribute the stress of deformation uniformly along the lip 3, according to the embodiment shown on figures 3A to 3C, the surface 40 of the shoulder 4 placed against the container neck C and/or the platform 2 may have a section shape complementary to the edge B.

In the embodiment of figure 1D, the lip 3 comprises a first linear segment 31 connected at one end to the inner surface of the shoulder 4 and at its other end to a second linear segment 32 via an elbow portion 30.

The elbow defines an angle a between the two segments 31 and 32, which may be positive or negative, of 0 to 60 from the axis of the first segment 31 to one or the other.

The lip 3, here the first section 31, has an inclination β with respect to the X-axis of the lid, which is 20 to 60 °.

As shown in fig. 1C, such geometry enables, in the closed position, to ensure the coincidence of the peripheral lip 3 with the upper edge B of the container neck.

More generally, the cross-sectional shape and thickness (0.2-0.6 mm) of the lip 3 and the geometry of the shoulder 4, and in particular of the protuberance 41, are determined in such a way that the lip 3 sealingly fits onto the periphery B of at least one portion of the edge B above the connection plane of the neck (not shown) of the container, covering, if necessary, the lower portion adjacent to the curved periphery B.

This connection plane is constituted by the ends of the vertical stiffeners resulting from the container manufacturing operation. In practice, the container, in particular the neck C of the container, can be moulded from its preform by means of a mould formed by two separable half-moulds which, between their edges of contact, define a narrow gap through which the plastic flows and which form the excess reinforcement ribs. These ribs continue to be present on the neck of the container after the final finishing.

Thus, a good seal is only ensured if the lip 3 is supported between surfaces polished by the container neck C, i.e. not having any rough surface, which can only be present above the plane of connection.

In the embodiment of fig. 1E, the peripheral lip 3 is connected to a centering and/or fastening collar 5 supported on the lower wall of the platform 2. The lowest point of the rim 5 is above the plane of the free end of the lip 3 at rest, i.e. in the pre-closed position shown in figure 1A. The platform 2 is preferably provided with a set of radial ribs 7 at its centre, which reinforce the rim 5 against it.

In the embodiment of fig. 2A to 2C, the sealing means is formed by an elastically deformable annular inner lip 6.

The annular inner lip 6 is here fixed to the platform 2 at an inclination γ of 0 to 45 ° with respect to the axis X of the cap, the diameter of the connection with the platform 2 being between the outer and inner diameter of the neck C of the container.

Thus, in the closed position of the lid, under the effect of the stresses, the free end thereof will abut against the curvilinear inner periphery B' of the upper edge B of the container neck C, so that the seal ensured by the peripheral lip 3 with the outer periphery B of the edge B is ensured complementarily.

In the position shown in figure 2C, the inner lip 6, supported by an inner shoulder 52 fixed to the lower surface of the platform 2, is inserted and compressed under stress between the radial projection 51 and the upper edge B of the neck of the container, exactly as the peripheral lip 3 between the outer shoulder 4 and the edge B.

According to an embodiment not shown, the lip 6 has or consists of a separate annular or disk-like element which sits on the bottom of the lid.

Here, the surface of the shoulder 52 which rotates against the container neck C has an undercut 50 above the projection 51, which acts similarly to the undercut 40 of the shoulder 4.

In the embodiment of fig. 3A to 3C, the annular rim 5 extends downwardly and coaxially with the container neck C against the lip 3.

The annular rim 5 defines, together with the external shoulder 4 and the lip 3, a groove 20 in which, in the closed position, the upper edge B of the container neck C is to be received to ensure a centred and complementary seal of the container neck C.

The lower surface of the platform has a ring 21 which projects in the groove 20 in the direction of the lip 3. This ring 21 is secured on the circular line of the platform 2 and centered by the transfer of the lip 3 by means of the support of the neck C of the container.

Although only described with respect to fig. 3B and 3C, this ring 21 can be used with any of the embodiments shown in the figures.

The radially outer surface of the rim 5 is provided with a boss 53 at its lower portion.

This boss 53 bears on the inner side wall of the container neck C in the semi-closed position (fig. 3B) and in the closed position (fig. 3C), which causes the lower part of the rim 5 to turn towards the inside of the container neck.

The inclination of the rim 5 and the contact of the projection 53 with the inner wall of the neck C of the container are such as to provide a second supplementary sealing zone to the sealing zone located on the outer periphery B of the rim B.

In the embodiment of fig. 4A to 4C, in the closed position of the lid, the height of the annular rim 5, at which the projection will be placed inside the neck C of the container, is greater than the operating stroke of unscrewing before the separation of the non-pryable strip 11 due to the breakage of the frangible zone 12.

In this condition, the upper edge B of the neck C of the container meets the end of the skirt 5 first as it moves upwards, and then exits last as it descends.

Such an arrangement thus makes it possible to maintain the tightness against various improper degassing and/or atmospheric exposure detrimental to the quality of the liquid product, even without causing breakage of the frangible zone 12 in the event of accidental partial unscrewing or non-screwing.

When carrying out the operations of manufacturing, transporting and storing the containers and/or preforms sporadically, the inner wall of the neck of the container is always protected from external attack that causes differences from the outer wall, particularly in the case of containers.

It follows that, thanks to the advantageous synergy of the different sealing means, according to the invention, the inner surface of the neck of the container, which will come into contact with the inner lip 6 and/or the boss 53, will contribute to obtaining a high level of sealing, whatever the conditions of use.

Claims (16)

1. Cap for containers for products of the liquid type, comprising a side skirt (1) having on one hand an internal thread (10) and a lower non-pryable band (11) and on the other hand an upper platform (2) internally provided with sealing means cooperating with the upper edge (B) of the container neck (C), the sealing means having an elastically deformable peripheral lip (3), said peripheral lip (3) extending, at rest, below the axis (x) of the cap, characterized in that said sealing means further comprise an external shoulder (4) provided at the junction of said side skirt (1) and upper platform (2), the external shoulder having a radial projection and supporting said peripheral lip (3), said peripheral lip (3) being intended to be interposed, in the cap closed position, between the projection of said shoulder (4) and said container neck (C), and under stress, to abut against at least a portion of the curved outer periphery (B) of the upper edge (B) of the neck of the container.

2. A cap according to claim 1, characterised in that the sealing means further comprise an elastically deformable annular inner lip (6) which, in the cap-closing position, is such that its free end rests under stress against the inner periphery (B') of at least a part of the upper edge (B) of the neck of the container.

3. A cap as claimed in claim 2, characterised in that said inner lip (6) consists of a separate annular element arranged in the cap.

4. A cap according to claim 2 characterised in that the inner lip (6) has a diameter at the junction with the platform (2) which is between the outer and inner diameters of the container neck (C) and which is inclined at an angle (γ) of between 0 ° and 45 ° to the axis of the cap.

5. A cap as claimed in any one of claims 2, 3 or 4, wherein said inner lip (6) is adapted to be interposed under stress between an inner shoulder (52) secured to the inner surface of the platform (2) and the neck (C) of the container when the cap is in the closed position.

6. A cap according to claim 1, characterized in that the surface of the external shoulder (4) and/or the internal shoulder (52) placed against the neck (C) of the container in the closed position of the cap has an undercut (40, 50).

7. A lid as claimed in claim 1, characterised in that said platform (2) is provided with a set of radially reinforcing ribs (7) at its centre.

8. A cap as claimed in claim 1, characterised in that said sealing means further comprises a centering and/or fastening bead (5) fixed to the platform (2) and extending coaxially against said peripheral lip (3), defining with said external shoulder (4) and/or lip (3) a groove (20) in which the neck (C) of the container is to be received when the cap is in the closed position.

9. Cap according to claim 8, characterized in that the radially outer surface of said skirt (5) has, in its lower part, a projection (53) for resting on the inner side wall of the neck (C) of the container.

10. A closure as claimed in claim 8, wherein in the closed position of the closure the raised rim portion (5) of the container neck has a height greater than the operating stroke of unscrewing of the screw prior to separation of the non-pryable band (11).

11. A cap as claimed in claim 1, characterised in that the peripheral lip (3) is connected to the lower surface of the outer shoulder (4).

12. A cap as claimed in claim 1, characterised in that said peripheral lip (3) comprises a first straight segment (31) connected by one end to said outer shoulder (4) and, at its other end, extending to a second straight segment (32) via an elbow portion (30).

13. Lid as in claim 12, characterized in that said elbow-shaped portion (30) defines an angle (α) of 0-60 ° between the two sections (31, 32).

14. A cap according to claim 1, wherein said peripheral lip (3) or first section (31) thereof is inclined at an angle (β) of 20-60 ° with respect to the cap axis (X).

15. Cap as claimed in claim 1, characterized in that the thickness of said peripheral lip (3) and the geometry of the external shoulder (4) are determined in such a way that the supporting contact between said lip (3) and the upper edge (B) of the container neck is made above the container neck joint plane.

16. A lid as claimed in claim 1, characterised in that the lower surface of the platform (2) is provided with a ring (21) extending in the direction of the inner lip (3).