A PACKAGE CLOSURE AND A DEVICE AND A METHOD FOR PRODUCING A PACKAGE CLOSURE AND USE OF SUCH A DEVICE
FIELD OF THE INVENTION
The invention relates to a package closure and a method for producing a package closure. The present invention further relates to a device for producing a package closure and use thereof.
This type of package closures comprises a neck having an opening and a cap. One such type of caps is a screw cap. Package closures of this type are arranged in plastic materials having an inherent flexibility, such as thermoplastic materials or other plastic materials having similar properties. Package closures of this type are generally used in connection with packages for liquid foodstuff, such as milk, juice, water, yoghurt and similar but can be used for any type of package.
PRIOR ART
There are a plurality of different types of package closures in the prior art. One such type of device is for example disclosed in WO2009136836. The package closure disclosed in WO2009136836 comprises a neck provided with external threads and a screw cap being connectable with the neck through the threads of the neck.
One problem with such prior art package closures is that they are complex and expensive to produce and consequently require expensive and advanced equipment for production thereof. The production requires at least two moulding tools, i.e. one for the cap and one for the neck, wherein the cap, in addition, must be mounted on the neck. Hence, a plurality of production steps is required to produce such prior art package closures.
SUMMARY OF THE INVENTION
An object of the invention is to avoid the above mentioned drawbacks and problems of the prior art. The invention results in a simplified and more
cost efficient production method, in which the entire package closure can be produced in a single tool without subsequent mounting of different parts of the package closure, while the package closure according to the invention simultaneously can be arranged tamper-proof and resealable.
The present invention relates to a method for producing a package closure having a neck and a cap, comprising the steps of
a) by means of movable jaws and an outer tool core forming the neck and the cap in one single integrated piece, wherein the neck is connected to the cap through a notch,
b) by means of an inner tool core forming a flexible projection on an inner side of the cap for interaction with the inner tool core,
c) removing the jaws from the formed package closure,
d) displacing the outer tool core in relation to the package closure and the inner tool core to at least partially disengage the package closure from the outer tool core,
e) by means of the inner tool core retaining the cap by the projection formed on the interior side of the cap and simultaneously, by means of an ejector, displacing the neck in relation to the cap and thereby breaking the notch and to form a package closure having a cap mounted on the neck, and f) by means of the ejector displacing the package closure in relation to the inner tool core, so that the projection by its flexibility is disengaged from the inner tool core.
By forming the neck and the cap as a single integrated unit of, for example, plastic materials, after which the neck and cap are displaced in the axial direction in relation to each other, the production of the package closure can be provided in a quick and efficient manner in a single tool without the need for subsequent mounting of the cap on the neck.
The cap can be a screw cap with threads for interaction with threads on the neck. Surprisingly it has been found that a threaded neck and a threaded cap in a method according to one embodiment of the invention can be displaced axially in relation to each other, so that the threads of the cap are pushed over the threads of the neck and the threads engage each other
due to an inherent flexibility of the threads. The threads of the cap can be interior threads. Alternatively, the cap is arranged with exterior threads.
For example, the package closure is produced in a heated process, such as a moulding process, compression moulding process or similar, wherein the plastic material is heated and thereby softened. For example, the jaws are heated. While the plastic material still is heated to a predetermined temperature, which is dependent on the plastic material used, the plastic material is soft enough for the threads to be pushed into each other by axial displacement without screwing and without permanent deformation of the plastic material.
The cap can be formed with a radially extending top portion and an ax- ially extending and tubular portion having an interior thread. Hence, the tubular portion has larger diameter than at least a top portion of the neck. Hence, the outer tool core is arranged with larger diameter at an end portion for pro- ducing the cap than at a portion for producing the neck. The end portion of the outer tool core is consequently forced to pass at least the top portion of the neck, which is possible by the inherent flexibility of the plastic material, for example when the plastic material is heated. For example, one or more of steps d-f are performed within a few seconds after step c, such as 2-3 sec- onds, so that the plastic material has not cooled too much.
The method can comprise the step of forming a tamper-evident ring (also called tamper ring, tamper-proof ring, etc.). The tamper-evident ring can be formed between the cap, such as an end of the tubular portion of the cap, and the notch. The tamper-evident ring can be formed at the same time as the cap and the neck.
The invention also relates to a package closure comprising a neck provided with an opening, and a cap for closing the opening, wherein the cap comprises a top portion extending across the opening and in the radial direction in relation to a centre axis of the package closure, and a tubular portion extending axially and being provided with a thread, characterised in that an interior side of the cap is provided with a flexible projection for interaction with an inner tool core in a device for producing the package closure, so that the
cap is connected to the inner tool core during production thereof. Surprisingly it has been found that a package closure with a screw cap can be produced in a quick and efficient manner by means of the projection. The projection results in that the cap can be retained in the inner tool core and enables axial relative displacement between the cap and the neck when the threads of the cap are pushed over the threads of the neck.
The thread of the cap can be an interior thread, and the neck can be arranged with an exterior thread for interaction with the thread of the cap. Hence, the cap is arranged with a larger diameter than at least a top portion of the neck, where the cap is mounted.
The tubular portion of the cap can be provided with a tamper-evident ring, for example at an end of the tubular portion.
The top portion of the cap can be arranged with radially extending stiffening ribs for reinforcement in the radial direction. Hence, deformation of the cap during opening thereof is prevented or reduced, wherein easier opening of the cap is provided.
Hence, by the invention a package closure having a screw cap and a tamper-evident ring can be obtained in a joint tool and in a single production step in which both the neck and the screw cap with the tamper-evident ring can be formed simultaneously and the screw cap can be mounted during ejection of the package closure.
The invention also relates to a device for producing a package closure having a neck and a cap, comprising a movable first jaw, a movable second jaw and a tool core interacting with the jaws to form a mould for the package closure, and an ejector for ejecting the produced package closure, wherein the tool core comprises an outer tool core and an inner tool core being movable in relation to the outer tool core, characterised in that the outer tool core is arranged for forming, together with the jaws, a notch between the neck and the cap, and that the inner tool core comprises a portion for forming and in- teraction with a projection on the interior side of the cap, so that the neck, by means of the ejector, is displaceable in relation to the cap while breaking the notch when the cap is connected to the inner tool core through the projection.
The outer tool core can be arranged with an end portion for forming the cap, and a portion for forming the neck or at least a portion thereof, wherein the end portion is arranged with larger diameter than the portion for forming the neck. Surprisingly, it has been found that the wider end portion of the outer tool core can be forced to pass the thinner neck due to that the plastic material in the neck is flexible. Hence, a wider cap and a thinner neck can be produced simultaneously and by means of the same tool core. By the device a package closure with a screw cap can be produced in an efficient manner.
Further characteristics and advantages of the present invention will become apparent from the description of the embodiments below, the appended drawings and the dependent claims.
SHORT DESCRIPTION OF THE DRAWINGS
The invention will now be described more in detail with the aid of embodiment examples and with reference to the appended drawings, in which
Fig. 1 is a schematic section view illustrating a part of a device for producing a package closure, and a package closure during production according to one embodiment of the present invention, in which the device is in a position for moulding the package closure,
Fig. 2 is a schematic section of the package closure during production as illustrated in Fig. 1 , in which jaws and a counterpart of the device have been removed,
Fig. 3 and Fig. 4 are schematic section views of the package closure during production and a part of the device of Fig. 2, showing displacement of an outer tool core,
Fig. 5 is schematic section view of the package closure and a part of the device, in which a neck and a cap of the package closure are displaced in relation to each other during finishing of the package closure,
Fig. 6 is a schematic section view of the package closure and a part of the device, in which the cap has been displaced in relation to an inner tool core of the device during disengagement of the package closure from it,
Fig. 7 is a schematic section view of a part of the package closure according to one embodiment, in which the package closure is in closed position and a tamper-evident ring of the package closure is intact, Fig. 8 is a schematic section view according to Fig. 7, wherein the package closure has been moved from its closed position by screwing and the tamper- evident ring is broken,
Fig. 9 is a schematic section view according to Fig. 8, wherein the cap has been removed from the neck by screwing,
Figs. 10-14 illustrate a package closure and different details thereof according to one embodiment when the package closure is under production and the neck has not been displaced into the cap,
Figs. 15-18 illustrate a package closure and different details thereof according to one alternative embodiment when the package closure is under production and the neck has not been displaced into the cap, Figs. 19-24 illustrate a package closure and different details thereof according to another alternative embodiment when the package closure is under production and the neck has not been displaced into the cap.
THE INVENTION
Referring to Fig. 1 a package closure 10 during production and a part of a device for producing said package closure 10 is illustrated schematically. The package closure 10 is arranged in a flexible material, such as a suitable plastic material. For example, the package closure 10 is formed in a suitable
thermoplastic, such as polyethylene. The device comprises a movable first jaw 11 , a movable second jaw 12, a counterpart 13 and a tool core 14 interacting with the jaws 11 , 12 and the counterpart 13 to form a mould for receiving an amount of plastic material for producing the package closure 10. The device further comprises a movable ejector 15 for ejecting the produced package closure 10, which is described in more detail below. The device is arranged as a moulding tool for moulding plastic materials. For example, the device is arranged for moulding plastic materials, wherein the jaws 11 , 12 and/or the tool core 14 can be heated and/or cooled in a conventional man- ner. The jaws 11 , 12 and the tool core 14 are arranged with a particular form for providing the mould for producing the package closure 10 according to the invention, which form is evident by the description of the special features of the package closure 10 below.
The package closure 10 according to the invention is, for example, moulded in a single piece, wherein the cap 19 and the neck 8 are an integrated unit. The jaws 11 , 12 and the tool core 14 form a continuous mould for forming the neck 18 and the cap 19 in a single piece.
The tool core 14 comprises an outer tool core 16 and an inner tool core 17. The outer tool core 16 and the inner tool core 17 are displaceable in relation to each other. Hence, the outer tool core 16 and/or the inner tool core 17 is/are movable and displaceable in the axial direction.
In Fig. 1 the device is illustrated in a position in which the jaws 11 , 12 interact with the counterpart 13 and the tool core 14 to form the mould for moulding the package closure 10 and in which a package closure 10 is in the mould, i.e. in contact with the jaws 11 , 12, the counterpart 13 and the tool core 14.
The jaws 11 , 12 are movable in a direction substantially perpendicular to a centre axis X of the package closure 10, such as in the radial direction, which direction is illustrated by means of the arrow A in Fig. 1 , between a position for forming the package closure and a position in which the package closure 10 is disengaged from the jaws 11 , 12. Further, the counterpart 13 is movable in a direction along the centre axis X of the package closure, as il-
lustrated by means of the arrow B in Fig. 1 , between a position for forming the package closure and a position in which the package closure 10 is disengaged from the counterpart 13.
With reference to Fig. 2 the jaws 11 , 12 and the counterpart have been removed, wherein the package closure 10 is illustrated during production thereof together with the outer tool core, the inner tool core 17 and the ejector 5. The ejector 5 and the outer tool core 16 are displaceable in relation to each other in the axial direction, as illustrated by means of the arrow C in Fig. 2. Further, the ejector 15 and the inner tool core 17 are displaceable in relation to each other in the axial direction. When the jaws 11 , 12 and the counterpart 13 are disengaged from the package closure 10 the package closure 10 can, for example, be brought forwards in the axial direction by means of the ejector 15 in a direction along the centre axis x of the package closure, as described in more detail below.
In the illustrated embodiment the package closure 10 is substantially cylindrical having a circular cross section. The package closure 10 comprises a neck 18 with an opening, and a cap 19 for closing the opening. The neck 18 comprises an axially extending tubular first portion 20 and a radially extending thread 21 , such as an external thread. In the illustrated embodiment the first portion 20 is arranged with a second portion 22 arranged in an angle to the first portion 20 to facilitate connection to a package. For example, the second portion 22 is arranged for connection to a package by melting, welding, gluing or in any other suitable manner. For example, the second portion 22 projects substantially radially in relation to the first portion 20.
During production the cap 19 is connected to the neck 18, wherein the neck 18 and the cap 19 are formed in a single piece as one integrated unit of continuous plastic. At that time the cap 19 is connected to the neck 18 through a notch 23. In the illustrated embodiment, the notch 23 extends continuously between the cap 19 and the neck 18. Alternatively, the neck 18 and the cap are formed in a single piece having openings between the neck 18 and the cap 19, wherein a plurality of notches 23 are distributed around the package closure 10 between the cap 19 and the neck 18.
In the illustrated embodiment the cap 19 comprises a radially extending top portion 24 and an axially extending and cylindrical or tubular portion 25 connected thereto. The tubular portion 25 is arranged with a thread 26, such as an internal thread, for interaction with the thread 21 of the neck 18. Alternatively, the package closure 10 is formed without any thread, wherein the cap 19, for example, is arranged for connection to the neck 18 through a snap-on function. Alternatively, the cross section of the package closure 10 then is elliptic, triangular, rectangular or arranged with other shape, with or without rounded corners.
In the illustrated embodiment, the package closure 10 comprises a tamper-evident ring 27. During forming of the package closure 10 the tamper- evident ring 27 is arranged between the cap 19, such as the tubular portion 25 of the cap 19, and the notch 23.
The cap 19 is provided with a projection 28 projecting from an interior side of the cap 19, such as the top portion 24. For example, the projection 28 extends substantially axially. The projection 28 is arranged between the centre axis X and the tubular portion 25. The projection 25 is flexible and arranged for interaction with the inner tool core 17, so that the cap 19 is connected to the inner tool core 17 through the projection 28 during the produc- tion of the package closure 10. In the illustrated embodiment the projection 28 is arranged with a radially extending flange 29. To temporarily fasten the cap 19 the inner tool core 17 is, in the illustrated embodiment, provided with a recess 30 for receiving the projection 28 or the flange 29 of the projection 28. For example, the recess 30 extends radially inwards for receiving the pro- jection 28.
In the illustrated embodiment one end of the tubular portion 25 of the cap 19 or one end of the temper-evident ring 27 is connected to the neck 18 through a folding portion 31. The folding portion 31 is connected to the neck 18 through the notch 23. Alternatively, the folding portion 31 is connected to the cap 19 through the notch 23. The folding portion 31 is, for example, arranged continuously in the circumference of the package closure. Alternatively, a plurality of folding portions 31 are distributed around the circumference
of the package closure with openings between them to provide for easier folding and material savings.
With reference also to Figs. 3 and 4 displacement of the outer tool core 16 in relation to the package closure 10 and the inner tool core 17 is illustrat- ed schematically during a part of the production of the package closure 10 according to one embodiment of the invention. After forming the package closure 10 in a single piece and the cap is displaced axially in relation to the neck 18 and not mounted on the neck 18 the outer tool core 16 is displaced in the axial direction, wherein the cap 19 and the neck 18 are disengaged from the outer tool core 16.
The outer tool core 16 is arranged with an end portion 32 for forming the cap 19 and a portion 33 for forming the neck 18 or at least a part thereof. The end portion 33 is arranged with larger diameter than the portion for forming the neck 18. Hence, the neck 18, or a portion thereof, is arranged with smaller diameter than the cap 19, so that the cap 19 can be brought onto and to enclose at least a part of the neck 18. During displacement of the outer tool core 16 it is forced to pass the neck 18, which is made possible by an inherent flexibility of the plastic material the package closure 10 is made of. In Fig. 4 the neck 18 is illustrated disengaged from the outer tool core 16.
After the neck 18 has been disengaged from the outer tool core 16 the neck 18 and the cap 19 are displaced in relation to each other in the axial direction. For example, the neck 18 is displaced into the tubular portion 25 of the cap 19, as illustrated in Fig. 5, while the cap is kept in position by means of the projection 28. For example, the ejector 15 is displaced in relation to the inner tool core 17 while bringing the neck 18 along therewith and breaking along the notch 23. Hence, the notch 23 connecting the cap 19 and the neck 18 is broken to form the cap 19 as a first piece and the neck as a second piece, wherein the first piece is not integrated with the second piece. For example, the folding portion 31 is folded inwards during displacement of the neck 18 in relation to the inner tool core 17, wherein further displacement results in that the notch 23 is broken and further displacement results in that the neck 18 is brought into the cap 19 to be partially enclosed by the tubular
portion 25 of the cap 19. In the illustrated embodiment the neck 18 is pushed into the cap 19, so that the thread 21 of the neck 18 is pushed over the thread 26 of the cap 19, wherein the cap 19 is mounted on the neck 18 by axial displacement without any screwing. For example, the neck 18 is dis- placed into the cap 19 to a final position, as illustrated in Fig. 6, after which further displacement results in that also the cap 19 is displaced in the same direction, for example by a portion, such as an end portion of the neck 18, engages a suitable portion of the cap 19, so that a force transferred from the neck 18 to the cap 19 exceeds the force with which the projection 28 holds the cap 19 to the inner tool core 17, whereby the package closure 10 is finished and disengaged from both the outer tool core 16 and the inner tool core 17. Hence, Figs. 3-6 illustrate schematically an ejection process in which a moulded package closure 10 is ejected from the device while being finished by applying the cap 19 onto the neck 18. After moulding the package closure 10, when the material in the package closure 10 still is soft and not yet entirely has solidified or crystallized, both the ejector 15 and the inner tool core 17, for example, is brought axially forward while bringing along the package closure 10 in the same direction, so that the cap 9 and the neck 8 is disengaged from the outer tool core 16. Hence, the inner tool core 17 and the ejec- tor 15 are displaceable in the axial direction in relation to the outer tool core 16. Alternatively, the outer tool core 16 is pulled backwards in relation to the ejector 15, the inner tool core 17 and the package closure 10. Then, the ejector 15 is displaced axially forward in relation to the inner tool core 7 while the inner tool core 17 interacts with the projection 28 to retain the cap 19 in position, so that the neck 18, by means of the ejector 15, is displaced in relation to the cap 19 while folding along the notch 23 and breaking thereof. Hence, the ejector 15 is displaceable in the axial direction in relation also to the inner tool core 17. To temporarily retain the cap 19 the recess 30 engages the projection 28 or the radially inwards extending flange 29 of the projec- tion 28. Hence, the projection 28 is more rigid than the notch 23, wherein the notch 23 is folded and/or broken when the ejector 15 is displaced axially while the projection 28 not bends. After that the ejector 15 is brought further forward in the axial direction while bringing along therewith the package clo-
sure 10 in the same direction, so that the projection 28, by its inherent flexibility, is disengaged from the inner tool core 17 and can leave the device for production of the package closure 10. For example, after that the projection 28 returns to its original position by its flexibility.
The application of the cap 19 on the neck 18 and the ejection of the package closure 10 is, for example, performed within one or a few seconds after the moulding thereof, wherein the temperature of the material in the package closure 10 is above room temperature and, for example, above 40°C or about 60°C, so that the material is semi liquid during the ejection.
With reference to Fig. 7 a part of the package closure 10 is illustrated in its closed and intact position, wherein the thread 26 of the cap 19 interacts with the thread 21 of the neck 18 and the optional tamper-evident ring 27 is intact and not broken. To open the package closure 10 the cap 19 is screwed, i.e. turned or rotated, around the centre axis in a conventional manner, so that the tamper-evident ring 17 breaks and the cap 19, by the threads 21 , 26, is forced in the axial direction, usually upwards, from the neck 18, as illustrated in Fig. 8, until the cap 19 is disengaged from the neck 18, as illustrated in Fig. 9. After that the package closure 10 can be resealed in a conventional way by screwing the cap 19 onto the neck 18 again, wherein the tamper-evident ring 27 remains broken.
Figs. 10-14 show a package closure 10 and different details thereof according to one embodiment in which the package closure 10 is under production and the neck 18 not has been displaced into the cap 19. In the illustrated embodiment the cap 19 is arranged as a screw cap having the top por- tion 24, the tubular portion 25 and the thread 26. The neck 18 is arranged with the tubular first portion 20, the thread 21 and the second portion 22.
Figs. 15-18 show a package closure and different details thereof according to one alternative embodiment. Figs. 17 and 18 show more in detail an alternative locking portion 34, wherein Fig. 17 shows the locking portion 34 in a position before the cap 19 has been brought onto the neck 18 and Fig. 18 show the locking portion 34 in a position after the cap 19 has been brought onto the neck 18.
In the illustrated embodiment the top portion 24 of the cap 19 is arranged with radially extending stiffening ribs 35 for reinforcement in the radial direction. For example, the stiffening ribs 35 coincide with ridges 36 on an exterior side of the tubular portion 25 of the cap. For example, the stiffening ribs 35 extend at least 1-3 mm in the radial direction from a circumference of the top portion 24, such as 2-5 mm or 3-4 mm. For example, the stiffening ribs 35 extend along at least 20% of a radius of the top portion, such as 20- 50%.
With reference to Figs. 9-24 a package closure 10 and different de- tails thereof is illustrated according to another embodiment in which the package closure 10 is under production and the neck 18 has not been displaced into the cap 19. In the embodiment of Figs. 19-24 the projection 28 is arranged for interaction with an end of the neck 18 when the package closure 10 is entirely closed, so that the end of the neck 18 then is arranged between the tubular portion 25 of the cap 19 and the projection 28. The projection 28 is formed with the radially extending flange 29, wherein the flange 29 extends radially inwards and, for example, extends substantially in parallel with the top portion 24. Hence, a more rigid cap 19 is obtained with improved deformation resistance, for example, when the flange 29 interacts with the recess 30 of the inner tool core 7 during the relative displacement of the neck 8 and the cap 19 during production of the package closure 10. Simultaneously, material savings are obtained.
In the embodiment of Figs. 19-24 the neck 18 is provided with supporting elements 37 to reinforce the neck 18 and prevent the neck 18 from fold- ing when the cap 19 is brought onto the neck 18 while folding the folding portion 31. The supporting elements 37 extend axially, for example along a part of the interior side of the neck 8 in the lower portion of the neck 18, such as in connection with the radially extending second portion 22 of the neck 18. For example, a plurality of supporting elements 37 is distributed around the interior side of the neck 18. In the illustrated embodiment the supporting elements 37 are triangular having their apexes directed towards the top of the neck 18.
As is evident from the illustrated embodiments the folding portion 31 is inclined radially outwards in a direction towards the cap 19 during production of the package closure 10 and the neck 18 has not been displaced into the cap 19. For example, an angle between the centre axis X and the folding por- tion 31 is relatively large, such as at least 30 degrees, to ensure that the folding portion 31 is folded outwards and downwards when the cap 19 is brought onto the neck 18 or the neck 8 is brought into the cap 19. Alternatively, the folding portion 31 is bent outwards in the radial direction in a corresponding manner.