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Closure with three dimensionally shaped sealing means

Abstract: The present invention is directed to a closure with an improve sealing means. The sealing means is three-dimensionally shaped an inserted into a closure shell. The sealing means comprises a sealing disc with a side seal. The sealing disc positively engages with the outer shell of the closure.


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The Patent Description data below is from USPTO Patent Application 20090026166 , Closure with three dimensionally shaped sealing means

FIELD OF THE INVENTION

The invention relates to a closure for packages for liquids such as beverages. In particular the invention relates to a sealing means for containers for carbonated liquids such as soft drinks but is well adapted to seal other containers such as glass or PET containers with contents at above or below atmospheric pressure or having gaseous components or requiring a hermetic seal.

BACKGROUND OF THE INVENTION

Seals of closures are generally manufactured from several types of plastic, such as Polyethylene (from now on PE) or Polypropylene (from now on PP) or EVA-based materials such as Darex™ liner material. The latter is mainly used for the manufacture of liner closures; the material is less hard and less durable than PE. Softer material such as Low density PE (LDPE), ethylene vinyl acetate (EVA) or compounds based on polyolefine raw materials are often used as sealing material. More rigid materials such as Polypropylene are often used as a shell material of closures.

PROBLEM TO BE SOLVED

From prior art a vast amount of documents is available which are directed to closures and caps for sealing of containers. A selected range is explained subsequent.

SUMMARY OF THE INVENTION

WO04007296 of Buswell, Clive (General) et al. discloses a method and apparatus for positioning a disc in a closure. In particular, the invention relates to a method and apparatus for positioning a barrier disc in a self-sealing molded plastic closure having a sealing fin arrangement for providing a seal when the closure is applied to a finish of a container. An apparatus to position a disc into a closure comprises an insertion station for supporting the closure through the disc positioning process and a tool that is movable relative to the insertion station to drive the disc relatively into the closure. The tool comprises a plunger adapted to press the disc into the closure such that at least a portion of the disc is adjacent the top panel thereof, and a fluid flow passage through which fluid travels to apply fluid pressure to the disc and force the entire disc past the sealing fin and into a position at least adjacent the top panel.

DETAILED DESCRIPTION OF EMBODIMENTS

US2003098286, assigned to Owens Illinois, discloses a plastic closure with a plastic closure shell having a base wall and a peripheral skirt with an internal thread for securing the closure to a container finish. The closure further comprises an internal bead on the skirt adjacent to but spaced from the base wall. A plastic disk has a periphery loosely captured between the bead and the base wall of the closure shell. An annular ring extends axially from the base of the disk adjacent to but spaced from the periphery of the disk. A resilient liner is molded onto the disk over at least the central portion of the disk base and the disk ring. The ring urges the liner into sealing engagement with a radially inner edge of a container finish when the closure is secured to the container finish.

REFERENCE SIGNS

U.S. Pat. No. 6,581,793, assigned to Novembal, describes a cap adapted to be secured on a neck of a container. The cap includes a top wall and a depending annular skirt having an inner annular projection protruding from the inner side wall of the skirt. A fluid seal having a central transverse wall, an outer annular shoulder and a inner annular bead rests on the inner annular projection so as to define a space between the cap and the fluid seal into which the fluid seal is pushed when the cap is secured to the neck of the container to make a seal between the outer annular shoulder of the seal and the inner annular projection.

U.S. Pat. No. 5,762,219, assigned to SACMI Cooperative Meccanici Imola, discloses a plastic screw cap for closing of a container. The cap comprises a disk-like top portion and a cylindrical wall that extends from the rim of the disk-like top portion. The cap comprises an annular lip that protrudes from the disk-like top portion concentrically with respect to the cylindrical wall. The annular lip acts as a shoulder for a sealing liner, so that the liner, when the cap has been applied to the container, frontally and externally engages the rim of the mouth of the container. The liner is made in the closure by compression molding.

U.S. Pat. No. 6,202,872, assigned to Alcoa Closure Systems Int. Inc., is directed to a composite closure for a container. The closure has a top wall and an annular depending skirt. A disc-shaped sealing liner is positioned within the closure cap adjacent to the inside surface of the top wall portion. The liner includes an inwardly facing sealing portion at the periphery thereof, and further includes an annular seal bead which projects downwardly from the liner in a direction away from the top wall portion. The sealing liner is made by compression molding and is supported by the side wall of the skirt of the closure.

U.S. Pat. No. 6,783,015, assigned to Crown Cork & Seal Tech Corp., discloses a closure cap which comprises in a transition range between a cap base and a cap skirt a bulge for pressing a sealing disk against a container opening. The bulge comprises an undercut and sections for weakening of the bulge thereby giving the bulge radial flexibility.

US2003057176, assigned to Kerr Group Inc., is directed to a closure with a liner for a plastic container. The closure includes a top wall, an annular closure skirt depending from the top wall, an annular outer flexible seal depending from the top wall, and at least one annular pressure ring distanced apart from the outer seal. The outer flexible seal retains an outer edge of the liner against the outer surface of the container neck and prevents ingress of liquids. The annular pressure ring engages the liner to retain the liner against the end face of the neck during sealing. The liner is deformed in a three dimensional manner.

U.S. Pat. No. 4,629,083, of Druitt Rodney, describes a thermoplastic closure comprising a top wall and an internally threaded skirt. The closure is adapted to receive a resilient sealing disc in which an annular flexible protrusion depends from the inner side of the top wall adjacent the intersection of the top wall and skirt but spaced apart from the skirt. As the closure is applied to a container neck the protrusion acts to fold the periphery of the sealing disc over the outer edge of the container neck and onto the outer side surface and radius of the container neck to thereby effect a seal.

It is an object of the invention to provide a closure with improved sealing means. It is a further object of the invention to provide a sealing means that allows torque control during opening of the closure.

The invention is directed to a closure cap with an improved two part sealing means which is normally made outside the closure shell and then inserted separately for sealingly closing of an opening of a neck of a container. Due to the design the sealing means has a certain flexibility and thereby offers improved tolerance against imperfect neck finishes.

Closure caps as known from the prior art often have the disadvantage that the torque to remove the closure cap from a bottle neck is significantly varying. This is normally caused by the fact, that the sealing means is not shaped ideally and is during operation firmly pressed against the neck finish which prevents relative movement between the neck finish and the sealing means at a decent torque level. This problem can be overcome by a multi-part sealing means and a closure comprising such a sealing means according to the present invention. The relative movement thereby has not to take place between the sealing means and the neck finish but rather between the sealing means an outer shell of the closure.

A closure cap according to the invention in general comprises an outer shell with a top deck and a cylindrical side skirt extending perpendicularly from the top deck forming the outer side wall of the closure cap. The closure cap further comprises at least one fastening means to receive and safely hold a three-dimensionally shaped sealing disc which is inserted inside the closure cap. In general the sealing disc is made by injection molding a separate mold cavity. Alternatively it is possible to make the sealing disc by compression molding inside the outer shell of the closure although this method may be subject to certain restrictions with respect geometry and precision.

Under a thee-dimensionally shaped sealing disc a sealing disc is understood which extends not primarily in-plane as the sealing discs known from the prior art but rather has a significant extension out of plane to wrap around a neck finish and/or outside to form a seal spaced apart from an annular end surface of the neck finish. This means that the sealing disc has an concave shape suitable to not only seal in the area of the end surface of the neck finish but also to encompass and sealingly act upon an outer and/or an inner side surface of the neck finish. Thereby the sealing disc can be shaped that it seals on the outside of a neck finish significantly down from the annular end surface.

If appropriate the sealing disc is laterally supported by a skirt (second skirt, see below) arranged at the outer shell extending in general perpendicular from the top deck of the outer shell of the closure. This annular side wall is normally spaced apart by a gap from the outer skirt of the closure shell and provides a certain radial flexibility such that the adjacent sealing disc can deflect in radial direction. In an embodiment the sealing disc has an annular skirt (outer leg) which in a first section has an in general cylindrical shape being in a mounted position inside the closure shell adjacent to the annular side wall and in a second section at the ends radially protrudes above the annular side wall of the supporting skirt in the direction of the outer skirt of the closure. In that the sealing disc protrudes above the supporting skirt it can be prevented that the sealing disc is pulled inside and jammed during application of the closure cap onto a neck of a container.

The sealing disc is normally made outside of the closure separately and secured inside the outer shell by positive interaction, e.g. by a snap-on connection. In an embodiment the sealing disc comprises a top disc extending in a mounted position along an inner top wall of the top deck across the inside of the closure cap and a first annular skirt extending in general perpendicular from the outer rim of the sealing disc, to sealingly engage during operation with an outer side wall of the neck of a container. If appropriate the inner surface of the first annular skirt is at its lower free end funnel shaped, e.g. conical, extending radially outwardly and away (down) from the top deck of the closure in the direction of an inner side wall of the outer shell. In certain fields of application good results are obtained in that the inner side wall of the annular skirt of the sealing disc has a first section adjacent to the top disc which is in general cylindrically shaped and a second section spaced apart from the top disc which is funnel shaped as described above. To improve the sealing performance, the disc may comprise an undercut in the transition area of the first and the second section. The undercut is formed by an annular bead protruding radially inwardly and foreseen to be pressed during operation against an outer side surface of the neck finish. To prevent contamination and improve ease of application it is in at least certain fields advantageous if the sealing disc is shaped such that the lower free end of the second section of the sealing disc is in contact with the side wall of the outer shell. The sealing disc may be radially supported by a second annular skirt extending from the inner top wall of the top deck of the closure cap. In that the second section radially protrudes above the end of the second annular skirt, it can be prevented that the seal is jammed during application of the closure in that it is supported in axial direction. The annular skirt may act as a fastening means for the sealing disc in that it is shaped such that it positively engages with the sealing disc when the sealing disc is mounted inside the outer shell of the closure cap. To improve adaptability the second annular skirt may be spaced apart from the side skirt of the outer shell by a circumferential gap. If appropriate the second annular skirt can be laterally supported by radial ribs to the outer shell. In certain fields of application the circumferential gap is at least partially filled with material. Normally the annular skirt is designed to laterally (radially) support the annular skirt of the sealing disc and thereby improve the sealing performance. In that the second annular skirt is spaced apart from the outer shell of the closure the second annular skirt and thereby also the first annular skirt are flexible in radial direction allowing to wrap around the upper area of a neck finish.

If necessary it is possible to insert a barrier layer between the sealing disc and the outer shell. This can be done e.g. in the form of a separate barrier disc or by spraying or stamping a barrier material onto the rear of the sealing disc or into the outer shell of the closure. If appropriate the barrier layer can be incorporated into the outer shell of the closure by injection molding. E.g. in that a barrier layer or disc is applied onto a mold core and then overmolded before the sealing disc is inserted.

To control torque level it may be advantageous to design the outer shell and the sealing disc such that the sealing disc is in a controlled manner rotatable with respect to the outer shell when the closure is removed from the neck. Thereby it becomes possible that during opening of the closure the sealing disc is in difference to closures known from prior art not urged to move relative to the neck finish. Instead relative movement between the sealing liner and the neck finish may occur at least at the beginning of the opening movement. Thereby the removal torque can be kept in close limits.

In a first embodiment the outer shell of the closure cap can be designed with an upper part and a lower part which are functionally interconnected to each other by a hinge structure. Good results are obtained if the closure is equipped by a hinge structure as described in the international patent publication WO2005/007526. The lower part of the closure which acts a base of the closure cap comprises means to engage the lower part of the closure with the neck finish whereby the closure remains in a defined manner rotatable with respect to the neck finish. The upper part of the closure comprises the sealing disc and acts as a lid of the closure cap. To engage the lid of the closure with the neck finish the lid may comprise at its inside thread segments or other locking means to engage with appropriate counter means arranged at the neck finish. Good results are achieved by horizontal thread segments (no pitch) which interact with each other as a bayonet locking type.

In a second embodiment the outer shell of the closure cap comprises in the upper area an inner tread to be engaged with an opposite outer tread arranged at the outside of the neck finish. The closure cap may be equipped at the lower end of the outer shell with a at least partially detachable tamper band which indicates initial opening of the closure cap. Alternatively the closure can be designed as a snap on closure which is put over a neck finish.

The outer shell of the closure cap is normally made by injection molding of a shell material into a cavity of an injection molding tool. The sealing disc is normally made by injection molding of a liner material into a cavity an injection molding tool. The sealing disc and the outer shell of the closure cap are assembled after they have been made.

Depending on the field of application it is possible to fix the sealing disc in an other way then by positive interaction (snap on). Although it may cause certain drawbacks, it is possible to fix the sealing disc with respect to the outer shell of the closure alternatively or in addition by interconnecting the materials, e.g. super sonic welding or gluing. In certain fields of application it may be appropriate to design the sealing disc having an outside seal, a bore seal or a combination thereof. The fastening of the sealing disc in the outer shell must guarantee such that the sealing disc is not pulled out of the outer shell during normal operation of the closure.

Embodiment of the invention are described subsequently in more detail. In the different drawings identical reference signs indicate similar parts.

The closure cap comprises an outer shell with a top deck and a side skirt depending downwardly from the top deck forming an outer side wall of the closure . The closure cap further comprises fastening means suitable to receive a three-dimensionally shaped sealing disc normally made out of a liner material outside and then inserted into the outer shell of the closure cap . The fastening means of the shown embodiment comprises a second annular skirt extending in general perpendicular from the inner top deck of the closure and spaced apart by a circumferential gap from the outer side skirt of the closure . If appropriate, the circumferential gap can at least partially be filled with material or the sealing disc can reach into the circumferential gap . Thereby it is possible to adjust the lateral flexibility of the second annular skirt .

The sealing disc comprises a top disc and therefrom protruding first annular skirt . As it can be seen in the liner disc extends laterally adjacent across an inner top wall of the top deck . The first annular skirt extends downwardly (−z-direction) along the second annular skirt by which it is laterally supported. The annular skirt comprises a first section which is in general cylindrical and a second section which is shaped funnel-like (conical) extending radially outwardly and down. The second section protrudes above the end of the second annular skirt of the outer shell of the closure . Thereby it can be prevented that the sealing disc is jammed during application of the closure. In a transition area between the first and the second section , the skirt comprises an annular bead protruding radially inwardly forming an undercut. In a mounted position, when the closure is arranged on a neck finish (schematically indicated in by a dotted line) the annular bead forms sealing point on an outer side surface of the neck finish spaced a distance apart from a annular end surface . At the inside the first section is equipped with a block like circumferential shoulder which acts a mechanical stop and/or a top seal for the neck finish in axial direction (z-direction) during application of the closure . If appropriate the stop may be equipped with a V-notch acting as a top seal. The circumferential shoulder may be designed such that by pressing upon it in axial direction the outer skirt and thereby the annular bead are pulled inwardly improving the sealing performance. In the shown embodiment the sealing disc is equipped with an inner sealing means which acts upon an inner edge of the neck finish . The inner sealing means is designed as a flexible lip protruding down and radially inwardly. An outer surface is in general shaped conically and acts upon the inner edge of the neck finish . An inner surface is designed such that when exposed to internal pressure the sealing means is deformed in an outer direction and thereby increases the sealing force.

If appropriate locking means (not shown in detail), e.g. in the form of annular protrusions and corresponding undercuts may be foreseen in the area of the contact surface between the sealing disc and the outer shell and/or the second annular skirt of the closure . Thereby the positive hold of the sealing disc may be improved. The locking means are preferably designed such that they do not hinder the rotation of the sealing disc with respect to the outer shell about the central axis (z) of the closure .

As it can be seen in the herein described embodiment of closure is designed as a hinged closure which comprises a lower part (base) and an upper part (lid) which are functionally interconnected to each other by a snap hinge structure comprising two trapezoidal plates and film hinges . Thereby it is possible to achieve a large opening angle in the range of 200°. The closure further comprises a locking means to lock the lid in an open position with respect to the base of the closure . The locking means comprises a locking tooth arranged at base which is suitable to be engaged with a notch arranged at the lid of the closure . Both elements , are preferably designed such that they can easily be removed from the mold cavity. As it can be best seen in at the inside of the closure several thread segments , are present in the base and the lid , of the closure . In certain field of applications it may be appropriate to implement a different sealing means as shown here although the performance will suffer.

The closure cap comprises an outer shell with an internal thread by which the closure cap can be secured to a corresponding external thread of a neck finish. At the lower end of the outer shell a tamper band is attached by frangible bridges which are destroyed during initial opening of the closure . At the inside of the tamper band undercut segments are protruding radially inwardly to be engaged with an appropriate locking bead of a neck finish (not shown in detail).

As it can be best seen in the closure comprises a sealing disc which is arranged inside of the closure shell . A top disc extends along the inner top surface of the top deck and merges at its outer end into a first annular skirt which extends downwardly (−z-direction) along the second annular skirt of the closure shell . The annular skirt widens at its lower end into a funnel shaped section which radially protrudes above the end of the second annular skirt and covers the annular gap . Fastening means prevent that the sealing disc falls out of the outer shell of the closure cap . The fastening means of the present embodiment consist in an annular bead and a corresponding groove at the sealing disc and the outer shell . The sealing disc further comprises a olive type bore seal which during extends into an opening of a neck (not shown in detail) when the closure is applied. If appropriate the bore seal can be left away.