The present invention relates to an opening device for a packaging container, comprising a neck portion and a screw cap, the screw cap having a tubular first part arranged to enclose the neck portion and engage with the same to secure the screw cap to the packaging container and a second part arranged to close the first part at one end thereof. The invention also relates to a screw cap for use in such an opening device and a method of forming such an opening device.
Within the food industry, beverages and other products are often packed in paper or paperboard based packages. Packages intended for liquid food are often produced from a packaging laminate comprising a core layer of paper or paperboard and an outer, liquid-tight layer of thermoplastic material on at least that side of the core layer which will form the inside of the packages.
One kind of frequently occurring packages are the so-called carton bottles. In substance, these are composed of a lower part in the form of a sleeve of packaging laminate like the one described above, and an upper part in the form of a plastic top having a neck which is provided with an opening/closing means, such as a screw cap. The carton bottles are often produced in that sheets, so-called blanks, of packaging laminate are formed into tubes which are closed by sealing of two opposing edges of each sheet in an overlapping condition. Then, according to a first alternative, each tube is closed at one end by a top of thermoplastic material being directly injection-moulded onto the tube at that end. The injection-moulded top has a neck sealed by a membrane. In connection with a first time opening of the package, this membrane should be torn off along a tear notch, which is also produced in the injection-moulding operation, to enable consumption of the product in the package. After injection-moulding, the package is filled, sealed at the open end of the tube for achieving a sleeve and closing the package, and formed into the desired shape. Finally, the neck of the top is provided with a screw cap to enable opening and closing of the package when the membrane has been removed. Packages of this kind are commercialized by the applicant under the name Tetra Top (registered trade mark).
According to a second alternative, instead of injection-moulding a top directly onto the tube, the tube is slipped over a respective premade plastic top and arranged in such a way that a major part of the top protrudes from the tube. The premade top has a neck closed by a screw cap. After sealing of the top and the tube along a contact surface between them, the package is filled, sealed at the open end of the tube for achieving a sleeve and closing the package, and finally formed into the desired shape. As opposed to the package described in the paragraph above, this package has a one-step opening since no membrane needs to be removed to open the package. Packages of this kind are commercialized by the applicant under the name Tetra Aptiva (registered trade mark).
Injection-moulding of a top directly onto a tube in production of a package is, in many situations, desirable. On the other hand, a one-step opening of a package may also often be preferable. Reasons for this are, among others, that the first time opening of a two-step opening package often will result in a loose part, for example in the form of a membrane, which loose part could increase the risk of littering or of children choking when being in contact with the package. In U.S. Pat. No. 4,518,554, a method and an apparatus for moulding a container enabling a combination of these two features are disclosed. In accordance with this document, a cap is arranged with its open end facing outwardly in a female die. A male die, which is insertable into the female die and into the cap when the cap is arranged therein, is also provided. A top end portion of a preformed container body is partly inserted into the cavity formed between the female die with the cap arranged therein and the male die. Then, a synthetic resin is injected into the cavity to form the neck portion on the container body.
To give a consumer the possibility of investigating whether a package has been opened earlier, different types of safety means, so-called tamper proofs, exist. These are broken by the consumer in connection with a first time opening of the package.
The first package described above, whose top is injection-moulded directly onto the tube, has a built-in tamper proof in the form of the membrane. To be able to open this package (in the proper way) for the first time, the membrane needs to be removed. Thus, if the membrane is removed, the consumer knows that the package has been opened earlier.
The second package described above, whose top is pre-made before assembly with the tube, can be provided with a well-known taper proof in the form of a ring which, through breakable, thin connections spaced evenly along the ring, is attached to the bottom end of the screw cap. The ring is permanently connected to the neck of the top which means that the connections between the ring and the cap must be broken to enable removal of the cap from the package in connection with opening of the same. Thus, if the ring is disconnected from the cap, the consumer knows that the package has been opened earlier. The ring is locked to the neck by an annular flange arranged at a predetermined distance from the pouring opening of the package. The flange permits rotation of the ring but hinders movement of the ring in an upward longitudinal direction of the package. When the screw cap is turned for opening of the package, the threading forces the cap in the upward longitudinal direction. Since movement of the ring is obstructed in this direction, the thin connections between the ring and the cap are broken, one by one, by the cap turning. The ring is formed integrally with the screw cap and applied onto the top in connection with the capping operation.
The third package described above, whose neck portion is directly injection-moulded into the screw cap and onto the container body, has no build-in tamper proof. Further, a tamper proof as the one described above cannot be used in connection with this package since the resin injected into the cavity between the dies will fill all open spaces, also the open spaces between the ring and the screw cap. Thus, after such an injection, the spaces between the breakable ring-cap connections will be filled with resin. This will prevent the ring from rotating in connection with turning of the cap which means that all the connections between the ring and the cap will have to be broken essentially at the same time to enable opening of the package. Such an operation requires very high strength and the package will be extremely hard, or even impossible, to open. Clearly, this kind of tamper proof is very badly suited for this application. Accordingly, there exist a great need for a working tamper solution for packages of this and similar types.
An object of the present invention is to provide an opening device, a screw cap for use in such an opening device and a method of forming such an opening device which, at least partly, eliminate potential limitations of prior art. The basic concept of the invention is to provide a tamper solution suitable for a one-step opening package or packaging container having a neck portion of which at least a part is directly injection-moulded in connection with the manufacturing of the package. Said at least a part is arranged to “stand in the way” of a portion of the screw cap in the turning direction of the screw cap so as to cause a deformation of the screw cap when this is turned for a first time opening of the package. Thus, if the screw cap presents a certain deformation, the consumer knows that the package has been opened earlier.
The opening device, screw cap and forming method for achieving the object above are defined in the appended claims and discussed below.
An opening device for a packaging container according to the present invention comprises a neck portion and a screw cap. The screw cap has a tubular first part arranged to enclose the neck portion and engage with the same to secure the screw cap to the packaging container and a second part arranged to close the first part at one end thereof. The opening device is characterized in that a wall of the first part of the screw cap is provided with a weakening extending in a circumferential direction of the first part and a recess extending in a longitudinal centre axis direction of the first part. The recess is arranged to receive a projection of the neck portion, which projection is directly injection-moulded in the recess. A tamper flap of the first part, which tamper flap is defined by the weakening and the recess, is automatically deformable in connection with a first time opening of the packaging container by cap rotation. This is because of an edge of the tamper flap, which edge is defined by a surface of the recess, being initially obstructed in a cap rotation direction by the projection of the neck portion.
As stated above, the weakening extends in the circumferential direction of the first part. Naturally, the weakening may have a certain extension also in the longitudinal centre axis direction of the first part, which centre axis direction is perpendicular to the circumferential direction of the first part.
Similarly, the recess extends in the longitudinal centre axis direction of the first part. Naturally, the recess may have a certain extension also in the circumferential direction of the first part.
The weakening can be of many different kinds, e.g. a slit or a notch, continuous or discontinuous and formed in the inside or the outside of the first part of the screw cap. Naturally, the weakening may also be through, i.e. extend all the way through the wall of the first part, from the inside to the outside thereof.
Similarly, the recess can be formed in many different ways, e.g. as a hole or a slot, continuous or discontinuous and formed in the inside of the first part of the screw cap. Naturally, the recess may also be through, i.e. extend all the way through the wall of the first part, from the inside to the outside thereof.
The weakening and the recess may meet each other at some point, e.g. at a respective one of their ends, or be separated form each other. If the weakening and the recess are separated, the material between them will have to broken in order to release the tamper flap.
The projection of the neck portion is injection-moulded directly in the recess. As the name implies, a directly injection-moulded projection is a projection which is not pre-produced but instead produced, with the recess as template, in connection with assembly with screw cap. This means that at least a part of the screw cap is used as a mould. Thereby, the projection will fill the entire recess and engage precisely with the same to achieve the desired tamper function. More particularly, the projection will prevent the edge of the tamper flap from moving in the rotation direction of the screw cap when the package is opened for the first time. Instead, the edge will initially be locked against the projection which will cause the release and deformation of the tamper flap. If the recess and the weakening are not through in the wall of the first part, this release means that the wall has to be broken along the weakening and the recess.
Thus, the proof that the package has once been opened is the deformation of the tamper flap of the screw cap. An advantage with the invention is that a consumer easily can see if the package is unopened by just looking at the screw cap. Another advantage is the great reliability of the opening device which is achieved partly by the direct injection-moulding of the projection in the recess. Further, the package will still be easy to open since little or no extra torque is required to release the tamper flap. Also, the invention is beneficial when it comes to consumption of material. The tamper function is integrated in the screw cap which means that no additional element, such as a ring, is required. Finally, the invention is advantageous since it is mechanically relatively simple to realize.
The inventive opening device can be so constructed that the edge of the tamper flap is arranged to engage with the projection of the neck portion during initial rotation of the cap a predetermined number of degrees. During this initial rotation the tamper flap will form a growing loop projecting from the wall of the first part. Hereby it can be ensured that a complete release and a clear deformation of the tamper flap is achieved. According to this embodiment, the edge of the tamper flap is arranged to be released from engagement with the projection of the neck portion after the initial rotation of the cap the predetermined number of degrees. Hereby it can be ensured that the package is easy to open. Depending on which material the screw cap is composed of, the deformation will remain to some extent after the tamper flap has been released from engagement with the projection of the neck. Thereby, it will be obvious, even with the screw cap put back onto the package, that the package has once been opened.
The opening device according to the invention can be such that a part of the projection initially is arranged outside at least a part of the edge of the tamper flap. This enables for the tamper flap to be locked under the projection in the area of the edge adapted for cooperation with the projection. An advantage of this embodiment is that obstruction of the tamper flap edge in the cap rotation direction is facilitated.
According to one embodiment of the invention, the surface of the recess defining said edge of the tamper flap extends into the wall of the first part with a predetermined angle in relation to a radial direction of the first part. Thus, this surface, seen from an inner side of the screw cap, is inclined away from a centre line of the recess, which centre line extends in the radial direction of the first part. An advantage with this embodiment is that it is mechanically relatively uncomplicated to realize.
As discussed above, the weakening and the recess may be formed in different ways. As an example, the weakening could comprise two parallel sub weakenings arranged in the centre of the wall of the first cap part and the recess could be arranged there between. Obviously, with such a design, the tamper flap will be formed of an intermediate part of the wall. However, according to a certain embodiment of the invention, the opening device is such that the weakening is arranged at a distance from an edge of the first part, which edge surrounds an open end of the first part, and the recess is arranged between the edge and the weakening. Here, the tamper flap is defined by the weakening, the recess and the edge. Obviously, with this design, the tamper flap will be formed of an edge part of the wall. The advantage of this embodiment is that a particularly mechanically simple construction of the opening device is enabled. In accordance with this embodiment, the upwards movement of the screw cap in connection with opening of the packaging container will not be obstructed by the projection of the neck portion, as obviously could be the case with a tamper flap formed of an intermediate part of the wall.
Not only the weakening and the recess but also the entire screw cap can be constructed in a large number of different ways. According to one embodiment of the present invention, the first part of the screw cap comprises upper and lower concentrically arranged tubular elements contacting each other along a contact line. The upper element is arranged between the second part of the screw cap and the lower element. A minimum distance between an inside of the lower element and the centre axis of the first part is essentially equal to a minimum distance between an inside of the upper element and the centre axis of the first part. Further, a maximum distance between an outside of the lower element and the centre axis is larger than a maximum distance between an outside of the upper element and the centre axis. This embodiment enables for the lower element to protrude from the upper element on the outside but be in line with the same on the inside. Further, the recess is formed in the lower element and the weakening comprises a groove in the inside of the lower element being formed at the contact line between the upper and lower elements. This embodiment is beneficial since it enables a particularly clever manufacturing of the screw cap.
A screw cap according to the present invention is adapted for use in an opening device according to the above.
A method according to the present invention of forming an opening device for a packaging container, the opening device including a neck portion and a screw cap, the screw cap having a tubular first part arranged to enclose the neck portion and engage with the same to secure the screw cap to the packaging container and a second part arranged to close the first part at one end thereof, comprises providing a female die having a receiving space. It further comprises arranging the screw cap in the receiving space of the female die with the first part facing outwardly, providing a male die insertable into the female die and thereby into the screw cap when the screw cap is arranged in the female die and inserting the male die into the female die. The method is characterized in further comprising providing a weakening in a wall of the first part of the screw cap, which weakening extends in a circumferential direction of the first part and providing a recess in the wall of the first part of the screw cap, which recess extends in a longitudinal centre axis direction of the first part. It further comprises injecting a melt into a cavity formed between the screw cap and the male die to fill the recess with the melt and thereby form a projection of the neck portion which is received in the recess. The projection is arranged to cause an automatic deformation of a tamper flap of the first part, which tamper flap is defined by the weakening and the recess, in connection with a first time opening of the packaging container by cap rotation. This is achieved by the projection initially obstructing, in a cap rotation direction, an edge of the tamper flap, which edge is defined by a surface of the recess.
The characteristics discussed in connection with the inventive opening device are, of course, transferable to the inventive screw cap and method. Further, these characteristics may naturally be combined in the same embodiment.
The invention will be described in more detail with reference to the appended schematic drawings, which show examples of presently non-limiting preferred embodiments of the invention.
a and 1b are perspective views of a screw cap according to a first embodiment of the present invention.
a and 2b are perspective views of a screw cap according to a second embodiment of the present invention.
a and 3b are cross sectional views of a tool in manufacturing of a packaging container with an opening device according to the present invention formed in accordance with a method according to the present invention.
a, 4b and 4c are views from above showing three different states of the screw cap in
a and 5b are side views and
In
A wall 20 of the first part 12 is provided with three evenly distributed weakenings in the shape of grooves 22 extending in the circumferential direction C of the screw cap at a distance from an edge 24 of the first part. The grooves are formed as elongate indentations in the lower element 12b at the contact line 16. The base wall of each groove is formed by the upper element 12a of the first cap part whereas the side wall of each groove is formed by the lower element 12b of the first cap part. The width of the grooves in the radial direction R of the screw cap is essentially equal to the thickness of the wall 20 at the upper element 12a which means that the grooves will extend all the way through the wall 20, from the inside to the outside. Further, the wall 20 of the first part 12 is provided with three evenly distributed recesses 26 extending in the longitudinal centre axis direction L of the screw cap, between the grooves and the edge 24 of the first part. Each of the recesses 26 is associated and in direct connection with a respective one of the grooves 22. They extend, just like the grooves 22, all the way through the wall 20, from the inside to the outside. Each pair of recess and groove together with the edge 24 of the first part defines a respective tamper flap 28 extending from a base 30 to an edge 32. For reasons that will be obvious later, the surface of a recess defining the edge 32 of the respective tamper flap 28 extends into the wall 20 with a predetermined angle in relation to the radial direction R of the screw so as to give the recess the shape of a wedge.
The screw cap according to
a and 2b show another screw cap 34 for use with a packaging container in the form of a carton bottle of the initially described type, i.e. comprising a thermoplastic top and a laminate sleeve. Just like the screw cap illustrated in
The screw cap according to
An opening device according to the invention comprises a screw cap 10 or 34 as described above and a neck portion of a top of a carton bottle.
In a first production step, a screw cap is arranged in the cap receiving space 58 of the female die 56 and a sleeve 68 of packaging laminate is slipped onto the male die 62. The screw cap is of the type shown in
a, 4b and 4c show, from above, the screw cap 34 of the carton bottle 74 in
In
Above described is the production of a carton bottle with an inventive opening device comprising a screw cap of the type shown in
The above-described embodiments should only be seen as examples. A person skilled in the art realizes that the embodiments discussed can be modified and varied in a number of ways without deviating from the inventive conception.
As an example, above, a so-called injection-compression technique has been used in the production of the carton bottles. However, other moulding techniques could also be used, e.g. injection-moulding with a mould cavity whose volume is kept constant throughout the moulding operation.
As another example, above, a carton bottle comprising a top and a sleeve, which top is directly injection-moulded onto the sleeve, has been described. Instead of producing a carton bottle like this, i.e. by injection-moulding the whole top, including the neck portion, in one single step, the top could be produced in other ways. The top could, for example, be produced in two steps. In a first step, the neck portion could be separately injection-moulded directly in the screw cap. In a second step, the rest of the top could be injection-moulded between the neck portion and the sleeve. Of course, these two steps need not be performed directly after one another, which enables stock-keeping of pre-produced neck portions with respective caps. Obviously, a carton-bottle produced like this will have a joint, not only between the sleeve and the top, but also between the neck portion of the top and the rest of the top.
Further, the entire description above is directed towards a right-handed screw cap. Of course, the invention is equally applicable with a left-handed screw cap. Such a left-handed cap is obviously constructed differently from the right-handed cap. For example, the weakenings of a left-handed cap will have to extend in a direction opposite to the extension direction of the above described weakenings.
The above described screw caps have three tamper flaps each. Of course, they could have any number of tamper flaps and these tamper flaps do not have to be equidistantly arranged around the respective screw cap.
To achieve the desired deformation of the tamper flaps in connection with turning of the screw cap for a first-time opening of the carton bottle above, the recesses are formed in such a way that the edges of the tamper flaps are inclined away from a recess centre line extending in the radial direction of the screw cap. In this way, the projection of the neck portion, which is injection-moulded directly in the recess, will be arranged outside the tamper flap in the area of the edge. However, there exist many alternative ways in which the screw cap could be constructed to achieve the desired tamper flap deformation. For example, seen from a direction opposite the direction L shown in the figures, instead of being inclined as described above, the edge could be formed as an arrow pointing clockwise or counter-clockwise or a semicircular concave or convex arc. With either design, a part of each projection of the neck portion will be arranged outside a part of the edge of the respective tamper flap to achieve the initial entrapment of the tamper flap edge underneath the projection.
Finally, the screw cap and neck portion could be made of any suitable material, the ones given above just being exemplary. However, it is essential that the materials in the screw cap and the neck portion are adapted for direct injection-moulding, i.e. injection-moulding of one of the materials on the other, which is also called over-moulding. The materials must not be welded together or stick to each other when the hot melt for producing the neck portion contacts the screw cap.
It should be stressed that a description of details not relevant to the invention has been omitted and that the figures are not drawn according to scale.
Number | Date | Country | Kind |
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0601429-4 | Jun 2006 | SE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/SE07/00633 | 6/28/2007 | WO | 00 | 12/30/2008 |