Blade, method of cutting with the blade and packaging device

Abstract

 A blade (50) for cutting packages is applied in a vertical filling device. The blade (50) comprises a back (51) and a cutting edge (52), wherein the cutting edge is formed by an edge provided with at least two main teeth (53,54). According to the invention the cutting edge (52) comprises less than nine main teeth. The cutting of packages in a vertical filling device comprises of providing a blade and a foil strip, inserting the blade in the foil strip, perforating the foil strip, cutting the foil strip. According to the invention substantially two initial perforations are formed in the foil strip. From the two perforations the bag will cut or even tear further. In addition, there is a packaging device specified wherein means are applied for vertical filling of packages, wherein the packaging device is provided with such a blade.

Description

[0001] The invention relates to a blade for cutting packages in a vertical filling device, comprising a back and a cutting edge, formed by an edge provided with at least two main teeth. The invention also relates to a method for cutting packages in a vertical filling device, comprising of providing a blade and a foil strip, inserting the blade in the foil strip, perforating the foil strip and cutting the foil strip. The invention also relates to a packaging device for vertical filling of packages.

[0002] A blade for cutting packages in a vertical filling device is known. The known blade has saw teeth. Using the sharp saw teeth a foil can be cut in the packaging device. During the cutting of a foil strip the blade is moved at right angles to the foil strip, wherein the foil strip is cut. Cutting with a saw tooth blade causes a serrated edge in the package. The packages can contain a foil, in particular a laminate. Such packaging materials are easy to tear. When the package is provided with a starting cut, for instance the saw tooth profile, the package can be easily torn open from there on.

[0003] The saw tooth blade will wear during use. Regrinding of a saw tooth blade is expensive.

[0004] The object of the invention is to provide a blade which can be easily ground. The blade according to the invention is characterized by a cutting edge which comprises less than 9, preferably less than 7 and in particular less than 5 main teeth. The cutting edge can hereby be restored to a desired sharpness with simple and known grinding tools.

[0005] A perforation can be formed with a blade tooth. Main teeth are those teeth of the blade which will first make a perforation when the blade is inserted into the object for cutting. The connecting line between the protruding main teeth of the blade will be designated as 'front line'.

[0006] In the preferred embodiment of the invention the cutting edge has two main teeth. A simple form of the cutting edge is hereby assembled which can be readily ground. By making use of main teeth the foil is first perforated and then cut. When the foil material comprises a laminate the material will cut easily or the tear will be easily guided. It hereby also becomes possible to cut a foil strip without the package being provided with a serrated edge. Packages, in particular laminate packages, which are provided with a serrated edge can tear quickly, since such a serration can be a starting point for a tear which may form. Tearing of a package, either during cutting or during the transport after cutting, results in considerable losses. Using a blade provided with two main teeth to form two initial perforations in the foil strip, the individual packages are provided with a substantially smooth cut edge. The cut edge then does not have any starting points whereby the package could tear easily.

[0007] A blade with two main teeth has three separate edge parts for the cutting edge. There are two edge parts running from the sides of the cutting edge to the main teeth, and an inner edge part situated between the main teeth.

[0008] The blade is preferably applied as according to claim 3. The inner edge part is adapted to cut a part of the foil strip which has a higher resistance during cutting. This can for instance be the longitudinal weld which is arranged when packages are formed in a vertical filling device. At the longitudinal weld more than two layers of foil, in particular laminate, lie over each other, whereby cutting of this part will be more difficult.

[0009] Between two main teeth is preferably arranged an edge portion which comprises two parts which are at an angle and which come together. A discontinuous cut edge is hereby formed. This part is particularly favourable for cutting of the foil. Insertion of the main teeth results in tearing along the inner edge. Two initial tears will come together between two main teeth. The discontinuous edge portion, preferably formed by edges which each form an angle of more than 30° with the front line, ensures sufficient tearing/cutting of the foil parts to be separated. The edge parts form a mutual angle of more than 60°. This part preferably has a bracket form.

[0010] At least one main tooth preferably has a substantially asymmetrical form. The cutting properties of the blade can hereby be modified on both sides of the tooth point. The blade will be moved with the front line first toward the foil strip. The foil strip will have a perforation at the position where the main tooth perforates the foil. Herefrom, as the blade is moved further through the foil strip, the blade will cut the foil along the tooth edge. The angle of inclination of the tooth edge also determines the cutting speed of a blade through the foil. The greater the angle of inclination, the slower the cutting. At parts of the foil which offer more resistance to cutting, a greater angle of inclination can be applied so that this part is cut more slowly. A greater angle of inclination also results in reduced wear. The blade will accordingly have to be replaced less often. The angle of inclination is the angle between the tooth edge and the front line.

[0011] It is favourable for the blade to have a curved tooth edge. The tooth edge is the edge of the knife (in top view) which is inserted in the foil. The curvature of the tooth edge is adjusted to the resistance which the tooth edge will encounter during cutting/tearing. The tooth edge is then adapted to the specific requirements of the packaging device in which the blade is used.

[0012] The distance between two main teeth is preferably less than twice the length of at least one of the tooth edges of the respective main teeth. The inner edge part between two main teeth forms a smaller part than the outward sloping oblique tooth edges.

[0013] The main teeth are preferably arranged mirror-symmetrically relative to the centre of the blade. A simple form of the blade is hereby constructed which is easy to grind. In addition, the longitudinal weld is situated in the centre of the foil for cutting in the usual vertical filling devices. The inner edge part is then also situated in the centre, the main teeth are arranged symmetrically relative to the centre on either side of the location at which the longitudinal weld is situated.

[0014] The blade is preferably chamfered on the cutting edge side. The costs of manufacturing such a blade are thereby low.

[0015] The invention also relates to a method for cutting a package in a vertical filling device. The invention is characterized by forming substantially two initial perforations in the foil strip. The blade will hereby penetrate through the foil with force at only two points. The maintenance resulting from this method is hereby reduced. The operation resembles the operation of a drawing pin. Further insertion of the blade through the foil strip will involve cutting in four directions. Cutting/tearing takes place toward two sides from the initial perforation. The use of foil material, in particular laminate, has the advantage that this material is cut/the tear is guided easily.

[0016] There is preferably provided a foil strip which is provided with a longitudinal weld, and the initial perforations are formed on either side of this longitudinal weld. In this way a distinction can be made between cutting the part of the foil strip without longitudinal weld and the part with longitudinal weld. Special measures can be taken for cutting the longitudinal weld part.

[0017] It is favourable to cut into the parts of the foil strip at different angles. The angle of inclination of the cutting edge of the blade determines the speed of cutting, together with the insertion speed of the blade. When the blade is inserted into the foil strip at a constant speed, an acute angle of inclination of a tooth on the blade will cause slower cutting than a smaller angle. Slower cutting/tearing of the foil after the initial perforation can be used to cut a material with higher resistance.

[0018] In an area between the two initial perforations where the initial tears come together, cutting preferably takes place at an angle of more than 30°, and the respective edge parts preferably form a mutual angle of more than 60°. The tearing parts that come together are hereby cut sufficiently loose from each other.

[0019] The invention also relates to a packaging device for vertical filling of packages. The packaging device is characterized by a blade as described above. A packaging device is hereby provided which is cheaper in use.

[0020] In the preferred embodiment the blade is arranged such that the main teeth can engage on both sides of a longitudinal weld. At least four cutting directions are hereby defined when the blade is inserted into the foil strip. A smaller space between the main teeth can be readily utilized for cutting the longitudinal weld, while a larger area with a smaller angle of inclination of the cutting edge can be used to cut the remaining parts of the foil strip.

[0021] The invention will be further described with reference to the annexed figures. Herein:

Figure 1 shows a perspective view of a packaging device according to the invention.

Figure 2 shows five steps a-e of the packaging according to the invention.

Figure 3 shows a cross-section of the welding device provided with a blade according to the invention.

Figure 4 shows an embodiment of a blade according to the invention.

Figure 5 shows a detail of a perspective view of the preferred embodiment of a blade according to the invention.

[0022] Shown is a vertical filling device 1 wherein foil material 2, for instance a laminate, is arranged around a tube 4 at a collar 3. Filling material can be poured into tube 4 as according to arrow 5.

[0023] Packaging material 2 is engaged by belts 6, 7 trained over rollers 8-11 which are connected to a drive 12. Packaging material 2 can be moved downward along tube 4 by means of drive 12.

[0024] Packaging material 2 is connected along the length by welding device 13, so that a cylindrical packaging tube is formed. Welding device 13 constructs a welded connection 14 along the length of packaging material 2. This is the longitudinal weld 14.

[0025] Close to the outer end 15 of tube 4 the cylindrical packaging tube transforms into a bag-shaped package. The packaging material 2 is herein engaged by welding device 16 which is placed horizontally. Welding device 16 consists of two parts 17, 18. Welding part 17 is connected to part 19 which can be moved according to arrow 20 with pistons (not shown). Welding part 18 is connected movably to frame part 21 and can likewise be moved according to arrow 20. The welding parts can be moved toward and away from each other in horizontal direction. Welding device 16 is also movable as according to arrow 22 in the vertical direction.

[0026] Welding device 16 is adapted for welding and cutting through packages. The welding device comprises a blade according to the invention. The individual packages are collected on guide 24 and removed as according to arrow 23.

[0027] Figure 2 shows five steps (a-e), wherein the assembly of a single package is shown. Packaging material 2 is arranged around tube 4. Vertical welding device 13 connects the foil material such that a cylinder is formed. The sleeve of foil material 2 moves downward as according to arrow 25. Filling 26 is arranged through hollow tube 4. This filling drops downward due to the force of gravity.

[0028] A funnel-shaped bag of packaging material, filled with filling 26, is situated in step a beyond the outer end 15 of tube 4. This bag is situated between welding parts 17, 18. Welding device 16 can be moved as a whole as according to arrow 27.

[0029] Once sufficient filling 26 has been arranged the welding parts 17, 18 move toward each other, see step b. The sides of packaging material 2 are herein carried toward each other, thereby forming a bag 28 with filling 26. Welding parts 17, 18 weld the bag 28 closed on the upper side. Welding device 16 also seals on its underside the new funnel shape 29 formed between outer end 15 of tube 4 and welding device 16.

[0030] During the welding in step b the welding device 16 moves downward as according to arrow 27 at the same speed as foil material 2 according to arrow 25.

[0031] Figure 2c shows that package 28 is cut loose with knife 30 which is incorporated in welding device 16. Package 28 is now separated from packaging part 29, in which there is already new filling 31.

[0032] In step d the weld parts 17, 18 are moved apart as according to arrows 32, 33. Foil material 2 is moved further downward according to arrow 25, whereby a larger funnel 29 has formed, which is also filled with and is still being filled with filling material 31.

[0033] In step e the welding device 16 moves upward as according to arrow 34 in order to move back to the starting position according to step a. Funnel 29 is filled further. The method a-e can be repeated.

[0034] Figure 3 shows a cross-section of welding parts 17 and 18 which comprise engaging means 35-38, welding means 39 and 40 and a knife 30. The foil strip will be situated between the respective welding parts 17, 18. When welding parts 17, 18 are moved according to arrows 41 and 42, the engaging means of the respective welding parts will firstly make mutual contact. The engaging means 35-38 are flexible and can be compressed. Engaging means 35-38 guide the foil strip from the tube form to the flatter package form and can be embodied specially for this purpose. Engaging means 35-38 extend for this purpose over the width (horizontally) of the respective welding parts.

[0035] After the clamping engagement, the blade 30 will make contact with and cut the foil strip. The welding parts are then moved even closer toward each other, wherein welding parts 39, 40 will make contact with the foil strip and will engage the foil strip over the width of welding parts 17, 18 and weld them together. Welding is generally known. The welding method which is applied is adapted to the foil material used.

[0036] Welding parts 17, 18, and therefore blade 30, move toward each other in a horizontal plane. The blade is inserted horizontally. The blade 30 is flat in cross-section with a chamfered edge on one side tapering to a point. This is the cutting edge 43 of the blade. The back 44 of the blade is situated on the inside. The welding means have a cross-section in the form of a fork and are arranged around the blade so that a weld can be arranged below and above the knife, corresponding to a weld at the top of a severed package and a weld on the bottom of a new package to be formed.

[0037] Figure 4 shows a first embodiment of blade 50. A blade is shown with a back 51 and a cutting edge 52, wherein the cutting edge is formed by chamfering the flat blade to one side. Recesses are arranged in the blade so that the blade can be engaged. The cutting edge has two main teeth 53, 54. The main teeth 53, 54 divide the cutting edges into four parts 55-58. Cutting edge parts 56 and 57 together form the inner edge part 59 situated between the main teeth 53, 54. The inner edge part 59 has a width 60.

[0038] The main teeth 53, 54 lie in one line, the so-called front line 61. When the blade is inserted horizontally on a foil strip, the blade with the main teeth 53, 54 will make first contact with the foil strip. The main teeth 53, 54 will make an initial perforation in the foil strip. Further insertion of the blade results in the foil strip being cut along edge parts 55, 58. From the initial perforation, caused by main tooth 53, edge part 55 cuts the package loose toward the outside. The blade is at least as wide as the package for cutting. From the first perforation cutting takes place toward the middle along edge part 56. The same applies in mirror-symmetrical manner for main tooth 54 and edge parts 57, 58.

[0039] The use of blade 50 in the vertical filling device 1 according to figure 1 makes it possible to arrange the blade in welding device 16 such that the longitudinal weld 14 is situated between main teeth 53, 54. The advantage hereof is that the packaging is cut open toward the outside from main teeth 53, 54, while at the position where a plurality of layers of packaging material 2 lie over each other, particularly at the position of weld 14, the packaging material 2 is cut by edge parts 56, 57. Because the angle of inclination (ϕ1,ϕ2) of the inner edge is greater than the angle of inclination θ of side edges 55, 58, horizontal insertion of blade 50 into the foil strip at the position of edge parts 56, 57 will result in less fast cutting than at the position of edge parts 55, 58. Due to the greater angle (ϕ1,ϕ2) it is possible to overcome and cut through a greater resistance, for instance that of a longitudinal weld 14, with edge parts 56, 57.

[0040] The blade is mirror-symmetrical relative to the centre, so that no forces which cause the foil strip to deviate in width direction are exerted on foil strip 2 when the knife is inserted. This enhances an even inflow of the foil strip.

[0041] The angle of inclination of edge part 56 is greater than ϕ1 and/or ϕ2. Edge part 56 is curved, whereby the angle of inclination varies. With a curved cutting edge the force with which cutting takes place can be varied and even adjusted to the foil strip, when the internal resistances during cutting of the foil strip are known.

[0042] Figure 5 shows a detail of a second embodiment of the edge parts between two main teeth 70, 71. Shown are edge parts 72, 73, 74, 75, wherein edge parts 73, 74 form the inner edge part between main teeth 70, 71 in which a part of the foil strip with increased resistance can be received. When inserted in a foil strip, main tooth 70 will make an initial perforation in the foil strip. Further movement of the blade will result in cutting as according to arrows 76 and 77 close to the initial perforation. The same applies for main tooth 71 and cutting according to arrows 78, 79.

[0043] The cuts according to arrows 77 and 78 will come together close to the centre 80. In order to make the cut edge of the packaging straight, i.e. without serrations and other possible starting points for tears in the package, the centre 80 is made deeper so that a more acute angle of inclination is defined, whereby cutting takes place more precisely and such a starting point is prevented from being formed.

[0044] Close to centre 80 the cut edge is discontinuous. This part is particularly suitable for cutting loose the tears coming together between the two main teeth. The discontinuous parts both form an angle of at least 30° with the front line and 60° with each other.

[0045] With the blade according to the invention a vertical packaging device is provided, wherein packages can be cut which have a cut edge without serrations. Such packages do not tear easily during transport. Possible tearing of such packages during the packaging is also prevented, whereby the packaging process can proceed more rapidly without errors.

Claims

1. Blade for cutting packages in a vertical filling device, comprising a back and a cutting edge, formed by an edge provided with at least two main teeth,
characterized in that the cutting edge comprises less than nine main teeth.

2. Blade as claimed in claim 1, characterized in that the cutting edge has two main teeth.

3. Blade as claimed in claim 1 or 2, characterized in that an inner edge part is formed between a pair of main teeth in order to receive a foil strip part which has an increased resistance during cutting.

4. Blade as claimed in claim 1 or 2, characterized in that between a pair of main teeth there is arranged an edge portion which comprises two parts which are at an angle.

5. Blade as claimed in any of the claims 1-3,
characterized in that at least one main tooth has a substantially asymmetrical form.

6. Blade as claimed in any of the claims 1-5,
characterized in that a front line with a cutting edge which connects two main teeth has at least one angle of inclination which is more acute than the angle of inclination of the respective main tooth with the other cutting edge.

7. Blade as claimed in any of the claims 1-6,
characterized in that the main tooth has two tooth edges, wherein at least one tooth edge is curved.

8. Blade as claimed in any of the claims 1-7,
characterized in that the main teeth are arranged mirror-symmetrically relative to the centre of the blade.

9. Blade as claimed in any of the claims 1-8,
characterized in that the blade is chamfered on the cutting edge side.

10. Method for cutting packages in a vertical filling device, comprising of:

providing a blade and a foil strip

inserting the blade in the foil strip

perforating the foil strip

cutting the foil strip

   characterized by
   forming substantially two initial perforations in the foil strip.

11. Method as claimed in claim 10, characterized by providing a foil strip which is provided with a longitudinal weld, and forming the initial perforations on either side of the longitudinal weld.

12. Packaging device comprising means for vertical filling of packages, characterized in that the packaging device comprises a blade for cutting packaging material as claimed in any of the foregoing claims.

13. Packaging device as claimed in claim 12,
characterized by a welding device for arranging a longitudinal weld on packaging material.

14. Packaging device as claimed in claim 12 or 13,
characterized in that the blade is arranged such that the main teeth can engage on either side of a longitudinal weld.

Drawing