A PACKAGING CONTAINER WITH AN OPENING DEVICE, KNIFE APPARATUS AND METHOD TO PRODUCE SAID CONTAINER

Abstract: The present invention relates to packaging containers (10) for pourable food products, comprising a laminated, tubular packaging material with opposed end fin portions (11, 12) that have been produced by sealing and cutting a continuous packaging material web between consecutive packages. A line (14) of perforations extends across a corner of one of the end portions (11) to facilitate the opening of the container. The cut edge of the end fin portion (11) with the line (14) of perforations is provided with a bend (11d), so that a first segment (11b) of the cut edge extends more close to the product-filled part (13) of the container than a second segment (11c) of the cut edge. The second segment (11c) of the cut edge which is more distant from the product-filled part of the container than the first segment, forms a grip-tab (11a) for opening the perforated corner. The invention also relates to a knife apparatus and a method to produce the packaging container.

Description: A PACKAGING CONTAINER WITH AN OPENING DEVICE, KNIFE APPARATUS AND METHOD TO PRODUCE SAID CONTAINER TECHNICAL FIELD The present invention relates to a packaging container for pourable food products, comprising a laminated, tubular packaging material with two-opposed end portions that have been produced by sealing and cutting a continuous packaging material web between consecutive packages, wherein a line of perforations extends across a corner of one of said end portions to facilitate the opening of the container. The invention also relates to a knife apparatus for cutting the material web, as well as a method to produce the packaging container . BACKGROUND ART The invention relates to the technical field of packaging of pourable food products, such as fruit juice, heat treated milk subjected to so-called UHT (ultra high temperature) treatment, tomato puree, sauces, etc. Some food products, particularly for children, are sold in a liquid state for storage in a domestic freezer, and then consumed in a frozen state. Such products are packaged in packages that are manufactured from a previously sterilised or sterile- treated packaging material . A typical example of this kind of package is • the tetrahedral packaging container for liquid or pourable food products, which is known by the name TETRA CLASSIC ASEPTIC (Registered Trade Mark) , which is manufactured by folding and sealing of a web-shaped laminated packaging material . The laminated packaging material comprises a support layer, made of e.g. fibrous material such as paper, coated on either side with a thermoplastic material such as polyethylene . On the side of the laminated packaging material which is destined to be in contact with the food contents of the package, there is also a layer of barrier material, such as e.g. aluminium foil, which is also coated with a thermoplastic layer. In order to manufacture tetrahedral packaging containers of the above-mentioned type, filling or packaging machines are fed with laminated packaging material in web form. The packaging material web is sterilised in the packaging machine by the application of a chemical sterilisation agent such as e.g. hydrogen peroxide solution. Upon completion of sterilisation, the sterilisation agent is removed from the surfaces of the packaging material, for example, it may be vaporised by heating. The sterilised packaging material is folded and longitudinally sealed to form a tube, which is filled with sterile-treated food product. The tube passes between two pairs of endless chains bearing sealing members which clamp and seal the tube therebetween to produce a first sealed band of material extending in a first direction, and a second sealed band of material extending in a perpendicular direction. The resulting packages have a tetrahedral shape . The sealed packaging material bands are cut between consecutive filled and sealed tetrahedral packages . An example of this type of packaging machine is the TETRA CLASSIC ASEPTIC (Registered Trade Mark) filling machine, manufactured by Tetra Pak Stalvall, in Partille, Sweden. In order to open this type of package, several solutions have been proposed. One solution consists in the provision of a line of perforations, partially penetrating the outer layers of the laminated packaging material but leaving the internal barrier layer or layers intact , and extending across a corner of the package. By cutting or tearing along the perforations, the package was opened, and the contents could be poured from the package. However, it has been found that some persons, e.g. children and elderly, may have a problem to open this package due to the lack of finger power or due to the lack of suitable scissors. Another solution consisted in the provision of a hole formed in the package and covered by a pull-tab applied over the opening. In order to access the contents of the package, a user simply removes the pull- tab and accesses the contents of the package through the hole. However, in order to consume a frozen food product packaged in a tetrahedral package of the above-mentioned type, there is a general need to provide an improved means for opening the package . DISCLOSURE OF INVENTION One of the objects of the invention is to provide better means for opening a packaging container having a tear-off corner. Another object is to improve the aseptic properties of this type of container. Still another object of the invention is to avoid production of waste material . For these objects, the packaging container according to invention is characterized in that the cut edge of the end fin portion with the line of perforations is provided with a bend, so that a first segment of the cut edge extends more close to the product-filled part of the container than a second segment of the cut edge, wherein the second segment of the cut edge, which is more distant from the product- filled part of the container than the first segment, forms a grip-tab for opening the perforated corner. This grip-tab equipped corner makes it much easier to open the packaging container, both by providing a clear indication to which of the corners of the container that is provided with the tear-off facility, and by providing a larger grip surface for the fingers. Also, the protruding grip-tab provides a better leverage for initiating the tear-off. Preferably, the cut edge bend is located near the line of perforations. It is possible to cut both ends of the packaging container with identical knife means by providing the cut edge of the other end portion with a corresponding bend. It is advantageous to make the cut edge substantially Z-shaped. The tear-off process is further facilitated by providing the cutting edge bend with a notch into the perforation line of the end portion. The packaging container may be a tetrahedral packaging container, a parallelepiped packaging container, a wedge-shaped packaging container, or a non-folded pillow-shaped packaging container. A knife apparatus according to the invention is characterized in a cutting knife edge comprising a first edge segment and a second edge segment which is laterally displaced with reference to the first edge segment, and that the two edge segments are interconnected by means of a third edge segment which extends at an angle between said two edge segments . This knife apparatus makes it possible to cut the sealed web portion between consecutive packaging containers in a single operation, to provide a grip-tab without producing any waste material . The angle between the first edge segment and the third edge segment may be between 90° and 145° and more ! advantageously, the angle is about 120° . Preferably, the knife edge also comprises a fourth edge segment extending in a laterally opposing direction away from the third edge segment . The angle between the first edge segment and this fourth edge segment may be between 90° and 145°. The segments of the knife edge are preferably arranged in the same plane . A counterdie is provided for cooperation with the knife edge during the cutting operation, which may be manufactured from a thermosetting plastic. Advantageously, the thermosetting plastic is polyurethane . The method in accordance with the invention is characterized in the step of cutting the packaging material between two sealings in the sealed area between two containers, to simultaneously produce a trailing edge of a preceding container and a front edge of a following container, wherein each of the corresponding cut edges is provided with a bend, so that a first segment of the cut edge extends close to the product- filled part of one of said containers, and that a second segment of the cut edge extends close to the product- filled part of the other container. In an advantageous embodiment one of the wider cut edge end portions of the container is located at the end portion corner having the line of perforations, so that this corner forms a grip-tab. More precisely, the bend may be laterally located with reference to the sealed web, so that the grip-tab end portion ends near the perforations . BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described in a non- limiting manner in the following, with reference to the accompanying drawings, in which: FIG. 1 is a side view showing a tetrahedral packaging container according to a first embodiment of the invention; FIG. 2 is a perspective view of a knife apparatus according to the invention, for cutting a material web to produce a packaging container according to FIG. 1; FIG. 3 is an elevation view of the knife apparatus of FIG. 2 showing the knife edge; FIG. 4 is a side view showing the knife apparatus in operative position; FIG. 5 is a side view showing a part of a parallelepiped packaging container according to a second embodiment of the invention; FIG. 6 is a side view showing a wedge-shaped packaging container according to a third embodiment of the invention; and FIG. 7 is a side view showing a non-folded pillow- shaped packaging container according to a fourth embodiment of the invention. BEST MODE FOR CARRYING OUT THE INVENTION The tetrahedral container 10 shown in FIG.l, is essentially of a conventional type, having two sealed fin portions 11 and 12 and an intermediate product filled container portion 13. One of the four corners of the container is provided with a perforation 14 that partially penetrates the outer layers of the laminated packaging material but leaves the internal barrier layer or layers intact. According to the invention, the fin portion 11 is provided with a protruding grip-tab 11a, which is located at the corner which is provided with the perforation 14. The grip-tab 11a has been produced by cutting the fin so that the cut edge portion lib of its remaining part, i.e. except the cut edge portion lie of the grip-tab 11a, extends close to or immediately along the sealing weld 15 that seals the fin portion 11. The cut edge portions lib and lie are interconnected by means of a bent cut edge portion lid. The intersection between the bent edge portion lid and the edge portion lib is provided with a notch 16 into the perforation 14. The fin portion 11 has a shorter segment where the fin is wide and a longer segment where the fin is narrow. By using identical knives 17, of which one is shown in FIG. 2 and 3, a single cut is made at each end of the container, without generating any packaging material waste. The packaging material that has been "removed" from the fin portion 11 with the grip-tab is now transferred to the opposite fin portion 12, which has a longer segment where the fin is wide and a shorter segment where the fin is narrow. When the grip-tab corner is removed from the packaging container, the remaining part of the fin which may contain a residue of the very small volume of product that was trapped between the two sealing welds bridging two sealed containers, is also removed from this end of the container. Thus, the aseptic properties of this end of the container is improved. The knife 17 for cutting the sealed bands of packaging material between consecutive packages in the packaging machine, has a first linear segment 17a for cutting the unsealed part of the fin (i.e. the outermost part of the fin which remains unsealed) from the sealed part of the fin (located adjacent the product filled part of the package) along a linear tract. The knife also has a second shaped segment 17b for leaving a protruding grip-tab at one end of the fin, and a third intermediate segment 17c including an angled cutting edge 17d for forming a pre-cut tearing line between the grip-tab and the linear tract. FIG. 4 shows four knives 17 that are mounted with equal angular distribution around the circumference of a first rotatable member 18. A corresponding number of counterdies 19 are mounted in the same manner around the circumference of a second rotatable member 20, so that each knife cooperates with a corresponding counterdie . Each time the knives 17 and counterdies 19 meet, the material web 21 is cut off simultaneously producing ,t a trailing edge of a preceding container and a front edge of a following container. The concept of the present invention is of course also applicable to other types of packaging containers for pourable food products , for example to packaging containers 10', 10'', 10''' shown in Figures 5, 6, 7 and respectively known by the names TETRA BRIK, TETRA WEDGE and TETRA FINO (Registered Trade Marks) . Packaging container 10' (Figure 5) presents a parallelepiped shape and has a product-filled part 13' corresponding to the part 13 of packaging container 10 and delimited by end walls 25, first lateral walls 26 and second lateral walls 27 wider than first lateral wall 26 . Packaging container 10' has two sealed fin portions 28 (only one of which is shown) parallel one another and similar to fin portions 11, 12 of packaging container 10. Each fin portion 28 presents a main portion 29 folded on a relative end wall 28 and opposite corner portions 30 folded on respective first lateral walls 26 and having a substantially triangular shape. One of the corner portions 30 is provided with the perforation 14 and the protruding grip-tab 11a according to the present invention, described in detail above with reference to packaging container 10. Packaging container 10'' (Figure 6) presents a wedge shape and has a product-filled part 13'' corresponding to the part 13 of packaging container 10 and delimited by a bottom rectangular wall 31, a pair of isosceles trapezoidal-shaped lateral walls 32 projecting from wall 31 and having the minor side adjacent to wall 31 itself, and a pair of triangular-shaped lateral walls 33 projecting from wall 31 and joined to walls 32 to form a wedge 34. Packaging container 10'' has two sealed fin portions 35 (only one of which is visible in Figure 6) similar to fin portions 11, 12 of packaging container 10; one (not shown) of fin portions 35 is folded on wall 31, whilst the other one defines the wedge 34 and is provided with the perforation 14 and the protruding grip-tab 11a according to the present invention, described in detail above with reference to packaging container 10. Packaging container 10''' (Figure 7) comprises a non-folded pillow-shaped product-filled part 13''' corresponding to the part 13 of packaging container 10 and delimited by opposite sealed fin portions 36, 37 similar to fin portions 11, 12; a corner of fin portion 36 is provided with the perforation 14 and the grip-tab 11a according to the present invention, described in detail above with reference to packaging container 10. The invention is in no way limited to the shown embodiments but can be varied in a number ways within the scope of the appended claims. For example, instead of rotating members 18 and 21 for carrying the knives and the counterdies , these means may be mounted on respective sets of chains. The sealing arrangements for forming the packages may perform the sealing operation substantially simultaneously with the cutting operation.

Claims: CLAIMS 1. A packaging container (10, 10', 10'', 10''') for pourable food products, comprising a laminated, tubular packaging material with two opposed end fin portions (11, 12; 28; 35; 36, 37) that have been produced by sealing and cutting a continuous packaging material web between consecutive packages, wherein a line (14) of perforations extends across a corner of one of said end portions (11; 28; 35; 36) to facilitate the opening of the container, characterized in that the cut edge of the end fin portion (11; 28; 35; 36) with the line (14) of perforations is provided with a bend (lid) , so that a first segment (lib) of the cut edge extends more close to the product-filled part (13; 13'; 13''; 13''') of the container than a second segment (lie) of the cut edge, wherein the second segment (lie) of the cut edge which is more distant from the product-filled part of the container than the first segment, forms a grip-tab (11a) for opening the perforated corner. 2. A packaging container according to claim 1, characterized in that the cut edge bend (lid) is located near the line (14) of perforations. 3. A packaging container according to claim 1 or 2, characterized in that the cut edge of the other end portion (12) is provided with a corresponding bend. 4. A packaging container according to any one of claims 1-3, characterized in that the cut edge, is substantially Z-shaped. 5. A packaging container according to any one of claims 1-4, characterized in that the cutting edge bend (lid) comprises a notch (16) into the perforation line (14) of the end portion (11; 28; 35; 36) . 6. A packaging container according to any one of the above claims, characterized in that it is a tetrahedral packaging container (10) . 7. A packaging container according to any one of the claims 1-5, characterized in that it is a parallelepiped packaging container (10'). 8. A packaging container according to any one of the claims 1-5, characterized in that it is a wedge- shaped packaging container (10''). 9. A packaging container according to any one of the claims 1-5, characterized in that it is a non-folded pillow-shaped packaging container (10'''). 10. A knife apparatus for cutting a sealed band of packaging material between consecutive packages, in a machine for producing separate packaging containers (10, 10', 10'', 10''') for pourable food products, characterized in that it presents a cutting knife edge comprising a first edge segment (17a) and a second edge segment (17b) which is laterally displaced with reference to the first edge segment (17a) , and that the two edge segments (17a, 17b) are interconnected by means of a third edge segment (17c) which extends at an angle between said two edge segments . 11. A knife apparatus according to claim 10, characterized in that the angle between the first edge segment (17a) and the third edge segment (17c) is between 90°and 145°. 12. A knife apparatus according to claim 11, characterized in that the angle is about 120°. 13. A knife apparatus according to any one of claims 10-12, characterized in that the knife edge also comprises a fourth edge segment (17d) extending in a laterally opposing direction away from the third edge segment (17c) . 14. A knife apparatus according to claim 13 , characterized in that the angle between the first edge segment (17a) and the fourth edge segment (17d) is between 90° and 145°. 15. A knife apparatus according to any one of claims 10-14, characterized in that the segments of the knife edge are arranged in the same plane. 16. A knife apparatus according to any one of claims 10-15, characterized in that a counterdie (19) is provided for cooperation with the knife edge during the cutting operation, which counterdie is manufactured from a thermosetting plastic. 17. A knife apparatus according to claim 16, characterized in that the thermosetting plastic is polyurethane . 18. A method to produce a packaging container (10, 10', 10'', 10''') for pourable food products, comprising a laminated, tubular packaging material (21) with two opposed end portions (11, 12; 28; 35; 36, 37) that have been produced by sealing and cutting a continuous packaging material web between consecutive packages, wherein a line (14) of perforations extends across a corner of one of said end portions (11; 28, 35; 36) to facilitate the opening of the container, characterized in the step of: cutting the packaging material between two sealings in the sealed area between two containers, to simultaneously produce a trailing edge of a preceding container and a front edge of a following container, wherein each of the corresponding cut edges is provided with a bend (lid) , so that a first segment (lib) of the cut edge extends close to the product-filled part of one of said containers, and that a second segment (lie) of the cut edge extends close to the product-filled part of the other container (10, 10', 10'', 10'''). 19. A method according to claim 18, characterized in the step of locating one of the wider cut edge end portions of the container at the end portion corner having the line (14) of perforations, so that this corner forms a grip-tab (11a) . 20. A method according to claim 18 or 19, characterized in the step of locating the bend (lid) laterally with reference to the sealed web, so that the grip-tab end portion ends near the perforations (14) .

Inventors: PALMNAES MARKUS, PALMNAES, MARKUS
Applicants: PALMNAES MARKUS, TETRA LAVAL HOLDINGS & FINANCE, PALMNAES, MARKUS, TETRA LAVAL HOLDINGS & FINANCE SA
Application year: 1999
Main classification: B65D75
IPC codes: B65D5, B65D75