AU769899B2

AU769899B2 - Closure cap for container with threaded neck and fixing flange

Info

Publication number: AU769899B2
Application number: AU34383/00A
Authority: AU
Inventors: Alain Franchet
Original assignee: PRISPA HOLDING SA
Current assignee: Fullytop Sa
Priority date: 1999-03-23
Filing date: 2000-03-22
Publication date: 2004-02-05
Anticipated expiration: 2020-03-22
Also published as: TR200102787T2; PL364724A1; MXPA01009541A; CN1136129C; DE60000868T2; HK1048795B; AU3438300A; ES2188519T3; EA002875B1; EP1165391A1; PL202365B1; CA2367947C; ATE228463T1; EP1165391B1; DE60000868D1; CA2367947A1; ZA200107764B; DZ3142A1; EA200100890A1; LU90375B1

Abstract

The invention concerns a closure cap comprising a top sealing element (1) designed to be screwed on the threaded neck (C) of a container with a fixing flange (A) and a bottom tamperproof element (2) designed to be maintained by said flange (A) and to said top element (1) by a lining zone (12) capable of being ruptured at least partially when the cap is unscrewed, the bottom element (2) comprising an outer side apron (21) extended in its lower part by a flexible band (22) provided with projections (22a). The invention is characterised in that said flexible band (22) is produced by moulding by being directly oriented inwards and upwards so as not to be the seat of any internal stress in said position.

Description

CLOSURE CAP FOR CONTAINER WITH THREADED NECK AND FIXING

FLANGE

The present invention relates to a stopper for a receptacle having a threaded neck and a retaining collar.

The invention applies more particularly to closing receptacles for beverages, possibly carbonated beverages, for which sealing and tamperproofing requirements are very severe.

US 4 801 031 and EP 0 390 412 describe stoppers each comprising both a top sealing element for screwing onto the threaded neck of a receptacle having a retaining collar, and a bottom tamperproofing element designed to be retained firstly by said collar and secondly by said top element via a connection zone suitable for being broken at least in part during unscrewing, said bottom element having an outer lateral skirt extended at its bottom end by a flexible band provided with projections.

However, in those embodiments, the flexible band is always molded in its low position and is then folded inwards prior to use or during closure of the receptacle after the beverage has been inserted therein.

Thus, when the stopper is screwed onto the neck of the receptacle, the bottom element is caused to expand radially outwards as it passes over the retaining collar.

This harmful effect is a result of the resistance of the band against inward folding, which band is under stress because of the shape memory of the material.

In bottling plants, those embodiments also give rise to difficulties with automatic screw-tightening because the forces to be delivered must overcome the resistance of the bottom element against deformation, and that has repercussions on the torque to be applied and on the strength needed by the connection zone.

Furthermore, those embodiments cannot provide a satisfactory level of tamperproofing since the flexible band is attached directly to the bottom edge of the lateral skirt such that when it is in the folded position it releases sufficient space between the bottom element and the receptacle to enable a tool to be inserted and the stopper to be disengaged without breaking the connection zone.

US 5 846 471 discloses a method of manufacturing a stopper by means of a press, in which the tamperproofing element includes tabs made by molding so as to be oriented inwards and upwards.

However, when the core is removed during ejection from the mold, the tabs do not return to their molding position as a result of the loss of elasticity that results from a prior step of being folded out straight during unmolding.

In addition, the conventional mold-opening step does not on its own make it possible to return completely to the natural molding position.

An object of the present invention is to resolve those technical problems in satisfactory manner.

According to the invention, this object is achieved by means of a method of manufacturing a stopper of the above type by means of a press, the method being characterized in that prior to cooling of the flexible band, its elastic return towards its natural molding position is assisted and guided mechanically.

According to an advantageous characteristic, the wall thickness of the inner band of the bottom element is made with a mean value lying in the range 20% to 50% of the mean thickness of the outer skirt, and for a standard 28 mm neck, it is preferably of a thickness lying in the range 0.2 mm to 0.4 mm, depending on the material used.

According to another characteristic, said projections of the flexible band are made with essentially triangular faces forming upside-down halfpyramids.

In a first variant implementation, the flexible band is assisted and guided mechanically by means of a relative movement of the mold core.

In a second variant the flexible band is assisted and guided mechanically by means of a member that comes into play when the stopper leaves the press after being ejected.

According to an advantageous characteristic of the method, said connection zone is provided in an outer peripheral groove.

Furthermore, it is possible to connect the band to the inside face of the lateral skirt via a curved zone.

In a variant, a free end segment extending below the level of said curved zone is provided on the bottom edge of the lateral skirt.

In another variant at least one orifice enabling any residue to be evacuated is provided on said curved zone.

According to yet another characteristic, a centering bead for centering the bottom element and designed to come into radial contact with the retaining collar so as to improve tamperproofing is made on the inside face of the skirt.

The stopper of the invention adapts very easily to the various tools used in automatic bottling plants and in particular to all types of screw tightener including those that operate at very high rates of throughput on moving receptacles.

The top element of the stopper can be self-sealing or can receive any type of sealing gasket without that compromising the tamperproofing provided by the bottom element.

The stopper can thus be mounted on the receptacle with very little force, specifically because the flexible inner band is not the seat of any stress while in the folded-in state, and thus possesses considerable capacity for elastic deformation and/or bending while it is in this position.

Another advantage of the invention lies in the reduction in the weight of the stopper, in particular due to the reduction in the thickness of the respective walls of the top element and of the bottom element (outer skirt and/or inner band).

This saving in material is most advantageous in economic terms and is not accompanied by any reduction in the qualities required of the stopper concerning sealing and tamperproofing.

The invention will be better understood on reading the following description given with reference to the accompanying drawings, in which: Figures 1A and 1B are section views of two embodiments of the stopper of the invention; Figure 2 is a section view of a variant embodiment of the Figure 1A stopper after it has been mounted on the neck of a receptacle; Figure 3 is a section view of a variant of the stoppers of Figures 1A and 1B after it has been mounted on the neck of a receptacle; and Figures 4A, 4B, 4C, 4D, 4E, and 4F are diagrammatic half-views in section showing various stages in the method of manufacturing a stopper of the invention.

The stopper shown in Figures 1A and 1B comprises a top element 1 for screwing onto the threaded neck C (see Figures 2 and 3) of a receptacle that has a retaining collar A, with the stopper serving to seal the receptacle.

To this end, the top element 1 is provided with a thread F and a gasket J.

The stopper of the invention also has a bottom element 2 that serves to tamperproof the receptacle.

The bottom element 2 is designed to be retained firstly by the retaining collar A on the neck C and secondly by the top element 1 via a zone 12 that is suitable for being broken, at least in part, on the first occasion that the top element 1 is unscrewed from the receptacle.

The bottom element 2 has an outer lateral skirt 21 that is extended at its bottom end by an inner flexible band 22 that is provided with projections 22a.

The projections 22a are of the type described and shown, for example, in patent EP 0 635 434 where they have substantially triangular faces defining upside-down half-pyramids, or where they comprise corrugations.

The top edge of the inner band 22 is designed to come into upward abutment against the bottom face of the collar A while the top element 1 is being unscrewed, thereby holding the bottom element 2 down and causing the connection zone 12 to break, at least in part.

In the invention, the entire stopper is made as a single piece by molding (compression molding or injection molding) with its flexible band 22 directly extending inwards and upwards, i.e. in a relaxed position folded towards the top element and as shown in Figures 1A and lB.

Unlike the prior art, the implementation of the invention does not require the band 22 to be forcibly turned inwards after molding since it is already in this position while inside the mold.

Figures 4A to 4F are half-views in section of the stopper while in the mold for manufacturing it, with only four pieces of the mold being shown. Naturally, the vertical disposition shown in the figures with the band 22 at the bottom is selected in arbitrary manner and any other orientation could be used during molding.

The top piece a forms the top element 1 of the stopper while the core b defines its internal empty volume.

The bottom pieces c and d are designed to make the bottom element 2 of the stopper (Figure 4A).

When the mold is opened, the pieces a, b, c, and d move in the directions of the arrows.

The pieces a and d are moved apart in a first step (Figure 4B).

Withdrawal of the piece d releases the flexible band 22 which is pushed downwards so as to fold outwards by the shoulder bi of the core b on moving axially (Figure 4C).

The band 22 moves out of the way and is then received in a recess cil of complementary shape formed in the inside face of the side piece c thus allowing the core b to pass through.

Once free from the core b, the band 22 begins naturally to return towards its molding position (Figure 4D), with the skirt 21 remaining engaged and retained in the piece c. While it is returning, the band 22 is preferably assisted and guided mechanically before it cools down, either by means of an element of the mold such as the core b moving relative to the piece c (Figure 4E) or else by means of a special mechanical member (not shown) that comes into play when the stopper leaves the press after being ejected.

In both cases, ejection of the stopper requires the skirt 21 to be disengaged from the side piece c. This disengagement can be obtained by thrust from a central ejector and/or from relative movement of the piece c (Figure 4F) and/or from compressed air. After being released the stopper is then recovered by a conveyor (not shown).

Thus, unmolding of the bottom element 2 can be performed by forced deformation of the band 22 which unfolds elastically outwards and downwards relative to the stopper.

Consequently, as soon as the stopper has been manufactured the band 22 extends radially upwards inside the bottom element 2 in its rest position so as to avoid being the seat of any internal stress while in this position.

As a result, when the stopper is mounted on the neck C and while the band 22 is passing over the retaining collar A, it can easily deform and/or bend elastically outwards possibly going as far as to come into contact with the inside face 21a of the skirt 21. Nevertheless, this movement does not give rise to any offsetting of the skirt 21, thereby making it possible, in particular, for the connection zone 12 to be made to be very weak without running any risk of breaking while the stopper is being screwed on.

The presence of the projections 22a makes the band 22 very flexible and its inside diameter can thus vary so as to allow it to pass over the collar A regardless of the dimensional tolerances applicable to the collar.

In the embodiment of Figures 1A and lB, the generator lines of the inside face 21a of the lateral skirt 21 are in alignment with the generator lines of the inner lateral face la of the top element 1, beneath the thread F.

The mean wall thickness of the inner band 22 is smaller than the mean thickness of the outer lateral skirt 21, with its value lying in the range 20% to 50% of the mean thickness of the skirt 21 and, depending on the material used, preferably lies in the range 0.2 mm to 0.4 mm for a standard 28 mm neck.

The band 22 is attached to the inside face of the skirt 21 via a curved zone 23 which acts as a hinge allowing the band 22 to move. As shown in the figures, the bottom edge of the skirt 21 is preferably free and defines an end segment 24 that extends downwards below the curved zone 23.

The length of the segment 24 is matched to the shape of the neck C so as to make it impossible for the stopper to be engaged from the inside or so as to prevent any tool being inserted or indeed so as to prevent any operation being performed that could enable the receptacle to be opened fraudulently without separating the bottom elements 2.

Where appropriate, at least one orifice 23a is formed through the zone 23 as shown on the right-hand side of Figure 3. This orifice is intended to make it possible to evacuate any liquid residue due to a cleaning operation and/or to faulty filling of the receptacle, thus avoiding any risk of pollution or of bacterial contamination. The orifice 23a can be of various shapes depending on the nature and in particular the viscosity of the cleaning liquid and/or of the packaged liquid.

In the embodiment of Figures 1A and lB, the connection zone 12 is continuous and comprises molded bridges or discontinuous circumferential cutouts, e.g.

made by slitting.

In a variant (not shown), provision is also made to implement one or more axial and/or sloping cutouts extending over the entire height of the skirt 21 as far as the connection zone 12, thereby defining at least one strong bridge making it possible to retain at least part of the connection between the top and bottom elements 1 and 2 after the stopper has been unscrewed.

This variant is particularly useful for packages on deposit or that are recyclable where the receptacle and the stopper need to be treated separately because they are made of different materials.

In the embodiment of Figures 1A, 2, and 3, the connection zone is situated in a peripheral groove formed in the outside face 21b of the skirt 21.

In the variant embodiment of Figure 3, the inside face 21a of the skirt 21 has a continuous bead or discontinuous centering studs 25 for coming into radial contact with the retaining collar A so as to position the bottom element 2 correctly on the neck C of the receptacle in order to further improve tamperproofing.

P:\OPER\GCP34383-0.doc-0412/03 -8A- The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference numerals in the following claims do not in any way limit the scope of the respective claims.

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