Cutting unit

Abstract

A cutting unit (10) is provided for making transverse cuts and / or perforations to a string (2) of packaging containers (1) connected by a transverse seal (3). The cutting unit (10) comprises a knife assembly (20) and an anvil assembly (30) which are rotatable relative to each other to form a nip (12) for receiving the transverse seal (3) of the string of packaging containers (1). The anvil assembly (30) comprises an anvil blade (32) having a first region (34) and a second region (35) so as to produce a cut when the first region (34) is aligned with a knife edge (22) of the knife assembly (20) in the nip (12) and to produce a perforation when the second region (35) is aligned with the knife edge (22) in the nip (12). A method, computer program and computer readable medium storing the computer program for providing transverse cuts and / or perforations to a string of packaging containers connected by a transverse seal are also described.

Description

Technical Field

[0001] This invention relates to a cutting unit for laterally cutting packaging containers interconnected by lateral seals. The invention also relates to a method for providing lateral cutting, as well as a computer program and a computer-readable medium. Background Technology

[0002] Cardboard-based packaging containers have been commercially used for many years. One example is the tetrahedral shape, developed in the 1950s, which has proven well-suited for a wide variety of foods, such as fruit juices, milk, spreadable cheeses, popsicles, etc. The general technical concept of cardboard-based packaging containers involves sealing the two longitudinal ends of a roll of packaging material together to form a tube, filling the tube with the contents to be packaged, and providing top and bottom transverse seals to the tube to seal the individual containers. While the tetrahedral shape is achieved by providing mutually approximately perpendicular top and bottom transverse seals, other rectangular shapes are achieved by arranging the top and bottom transverse seals in parallel positions. During or immediately following the transverse sealing, the downstream container is separated from the upstream tube by a transverse cut near the transverse seal.

[0003] Lateral cutting is achieved through a cutting unit. This unit has a knife facing an anvil, and the connected packaging container is fed into the distance between the knife and the anvil. As the knife moves toward the anvil, it cuts open the lateral seal of the packaging container, thus separating it from a series of connected packaging containers upstream.

[0004] For certain packaging containers, such as the popsicle example above, it might be desirable to connect a number of individual containers together in a string by perforation, allowing consumers to easily pull out a single popsicle from the string when using it. Since this string of connected containers must be of a certain length, a specialized cutting device equipped with a knife and a punching tool is used alternately on the sealed series of connected containers.

[0005] While such a solution can provide ideal results from alternating cuts and perforations, it requires a great deal of manual configuration to change operating parameters, such as the thickness of the tube material, as well as the frequency and sequence of cutting and perforation.

[0006] Therefore, there is a need for an improved cutting device that offers flexible configurations, allowing the cutting device to be easily adapted to different cutting and perforation schemes. Summary of the Invention

[0007] The object of this invention is to at least partially overcome one or more limitations of the prior art described above. In particular, the object of this invention is to provide a cutting unit with a rotatable anvil that, depending on the rotation position, allows the associated blade to cut or penetrate packaging material.

[0008] To address these issues, a cutting unit is provided. The cutting unit is configured to provide transverse cuts and / or perforations to a string of packaged containers connected by transverse seals. The cutting unit includes a knife assembly and an anvil assembly that are rotatable relative to each other to form a pressure zone for receiving the transverse seals of the string of packaged containers. The anvil assembly includes anvil blades having a first region and a second region, such that a cut is created when the first region is aligned with the blade of the knife assembly in the pressure zone, and a perforation is created when the second region is aligned with the blade of the knife assembly in the pressure zone.

[0009] The advantage of the cutting unit disclosed herein is that, for each rotation of the anvil assembly, it can control which of the first or second regions of the anvil blade will form a pressure zone together with the blade edge. Therefore, for each rotation of the anvil assembly, it is also possible to determine whether a cut or a puncture should be made.

[0010] The first and second zones can be set on a common anvil surface, thereby enabling simplified control of the cutting unit operation.

[0011] The cutting board surface can be curved. Preferably, the cutting board surface has an eccentric radius. Therefore, each position on the cutting board surface will provide a predetermined action based on its distance from the blade. In other words, the width of the pressure zone can be controlled within the range of the first and second zones.

[0012] The first region can have a uniform surface. Therefore, a uniform cutting action will be produced across the entire width of the transverse seal of the packaging container.

[0013] In one implementation, the second region has multiple recesses. Therefore, at the locations of these recesses, the cutting action will be reduced, resulting in a perforation across the width of the transverse seal.

[0014] The depth of each indentation can increase circumferentially away from the first region. This means that the degree of piercing can be controlled by adjusting where the anvil blade will form a pressure zone with the cutting edge in the second region. Shallower indentations result in a less noticeable difference between the cutting and piercing actions, while deeper indentations have the opposite effect.

[0015] The width of each indentation can be increased in the circumferential direction away from the first region. Therefore, the size of the perforation, i.e., the lateral ratio between the cutting action and the perforation action, can also be controlled.

[0016] Each indentation can be triangular. This achieves a linear relationship between the width of the piercing action and the rotational positioning of the cutting board blade.

[0017] The recesses can be arranged in at least one linear array. This achieves linear perforation, providing consumers with convenient tear openings.

[0018] The indentations in the common array can be spaced at equal lateral distances. This also improves the tear opening for the user, because the force required to open the puncture is constant.

[0019] The cutting unit may also include a control unit configured to control the rotation of the anvil assembly relative to the blade assembly, such that a pressure zone is formed between a predetermined position of the anvil blade and the blade edge. This allows for automated control of the cutting unit's movement, resulting in significant flexibility in determining the characteristics of the final product (i.e., the assembled packaging containers).

[0020] According to a second aspect, a method is provided for providing a transverse cut and / or perforation for a string of packaged containers connected by a transverse seal. The method includes i) feeding the string of packaged containers through a cutting unit such that the transverse seal of the string of packaged containers is received between a knife assembly and an anvil assembly; and ii) rotating the knife assembly and anvil assembly such that the transverse seal of the string of packaged containers is received by a pressure zone formed between the blade of the knife assembly and the anvil blade of the anvil assembly. If the pressure zone is formed between a first region of the anvil blade and the blade, a cut is created; and if the pressure zone is formed between a second region of the anvil blade and the blade, a perforation is created.

[0021] According to a third aspect, a computer program is provided. This computer program includes instructions to cause the cutting unit of the first aspect to perform the steps of the method of the second aspect.

[0022] According to a fourth aspect, a computer-readable medium is provided. The computer-readable medium stores a computer program of the third aspect.

[0023] Other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. Attached Figure Description

[0024] Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, wherein...

[0025] Figure 1 It is a perspective view of a cut-out unit according to an implementation scheme;

[0026] Figure 2 yes Figure 1 A cross-sectional view of the cutting unit shown;

[0027] Figure 3a -b is a cross-sectional view showing the relative positions of the knife and anvil during the operation of the cutting unit;

[0028] Figure 4a This is a perspective view of the blade assembly that forms part of the cutting unit;

[0029] Figure 4b It is formed Figure 4a A side view of the blade of a portion of the knife assembly shown;

[0030] Figure 5a This is a perspective view of the anvil assembly that forms part of the cutting unit;

[0031] Figure 5b It is formed Figure 5a A side view of the cutting board blade, a part of the cutting board assembly shown.

[0032] Figure 5c This is a perspective view of a cutting board blade according to one embodiment;

[0033] Figure 5d yes Figure 5c A cross-sectional view of the cutting board blade shown;

[0034] Figure 6a -d is a cross-sectional view of different operations of the cutting unit, and

[0035] Figure 7 This is a schematic diagram of a method based on an implementation plan. Detailed Implementation

[0036] refer to Figure 1 The diagram shows a cutting unit 10. The cutting unit 10 is typically part of a roll-to-roll packaging machine configured to form, fill, and seal individual packaging containers 1 by converting rolls of packaging material into longitudinally sealed tubes. The tube is partially filled with a predetermined content before being supplied with transverse seals to form a string 2 of packaging containers 1 interconnected by transverse seals 3. This process is well known in the art and has been commercially successful by Tetra Pak.

[0037] The cutting unit 10 is positioned at a point on the packaging machine to receive the string 2 of the packaging container 1. Figure 1 As can be seen, the purpose of the cutting unit 10 is to cut the string 2 at the location of the transverse seal 3, thereby separating one or more packaging containers 1 from the upstream string 2. However, as will be explained further below, the cutting unit 10 is also capable of punching holes in the string 2.

[0038] The cutting unit 10 includes a knife assembly 20 and an anvil assembly 30. The knife assembly 20 is driven in a rotary manner by a first motor 40a. Similarly, the anvil assembly is driven in a rotary manner by a second motor 40b. The first and second motors 40a-b are preferably servo motors, allowing for precise rotational control of the knife assembly 20 and the anvil assembly 30.

[0039] The control unit 50 is part of the cutting unit 10 and is programmed to provide control signals to the motors 40a-b to control the rotation of the knife assembly 20 and the anvil assembly 30. The knife assembly 20 is connected to the anvil assembly 30 via a pivot point 60. A spring 62 applies a spring force between the knife assembly 20 and the anvil assembly 30 to enable precise positioning of the knife assembly and the anvil assembly.

[0040] The cutting unit 10 is preferably positioned in the horizontal direction so that it can receive the string 2 of the vertically running packaging container 1.

[0041] Figure 2 A cross-sectional view of the cutting unit 10 is shown. The knife assembly 20 includes a rotating shaft 21 driven by a motor 40a. The rotating shaft 21 carries the blade 22. In a similar manner, the anvil assembly 30 includes a rotating shaft 31 driven by a motor 40b. The rotating shaft 31 carries the anvil blade 32.

[0042] like Figure 2 As shown, when the blade 22 and the cutting board blade 32 are positioned face-to-face in their respective locations, they define the pressure zone 12. When the string 2 of the packaging container 1 is received into the pressure zone 12, a cut or perforation is created. By controlling the rotation of the blade assembly 20 and the cutting board assembly 30, it is possible to determine at which position of the string 2 the cut / perforation should be made.

[0043] exist Figure 3a A more detailed cross-sectional view of the cutting unit 10 is shown in the figure. To further enhance the understanding of how the cutting unit 10 operates, string 2 is schematically shown.

[0044] As shown in the figure, the rotation axes 21 and 31 have similar shapes, with polygonal cross-sections. The shapes of the rotation axes 21 and 31 allow each axis to change its lateral distance to string 2 as it rotates. Therefore, in Figure 3aIn the rotational position shown, axes 21 and 31 provide a minimum distance between each other, thus forming the pressure zone 12. Preferably, in this position, the blade 22 is not in complete contact with the cutting board blade 32. As an example, the pressure zone 12 can be formed by a lateral distance of approximately 5-20 μm between the blade 22 and the cutting board blade 32. This is particularly advantageous for packaging materials with a paper-based core layer, as such materials would break due to the sudden compression formed in the pressure zone 12, thus still inducing a cutting action. However, since there is no actual contact between the blade 22 and the cutting board blade 32, the wear on the blade 22 is also greatly reduced.

[0045] As shafts 21 and 31 continue along Figure 3a As shown, rotating in the direction indicated, the blade 22 and the anvil blade 32 will move further away from each other. Due to the non-circular shape of the shafts 21 and 31, the lateral distance between the shafts 21 and 31 will also increase, thereby allowing the string 2 to pass through the cutting unit 10.

[0046] The positions of the knife assembly 20 and the cutting board assembly 30 are shown in this configuration. Figure 3b As can be seen from the diagram, string 2 can pass through without being blocked by axes 21 and 31. Once axes 21 and 31 return... Figure 3a The relative minimum distance will form the pressure zone 12 again, which will cause a cut or perforation at the string 2 of the clamped packaging container 1.

[0047] Each end of each rotating shaft 21, 31 has rings 21a-b, 31a-b. Rings 21a-b of the knife assembly 20 are fixed, while rings 31a-b of the anvil assembly are equipped with bearings. During the assembly of the cutting unit 100, rings 21a-b, 31a-b are connected by springs 62 (see...). Figure 1 They are pressed together with a force of approximately 2-5 kN. Since the anvil assembly 30 is provided with bearings in the rings 31a-b, rotational control of the anvil assembly 30 relative to the knife assembly 20 is still possible.

[0048] An example of the knife component 20 is in Figure 4a The -b option provides more detailed information. For example... Figure 4a As shown, the cutting edge 22 is mounted on the shaft 21 such that the cutting edge 22 extends axially along the shaft 21. Screws or bolts can be used to secure the cutting edge 22 to the rotating shaft 21. The shaft 21 forms a circumferential surface, thereby allowing the cutting edge 22 to project radially at a specific circumferential position on the shaft 21. Therefore, the cutting edge 22 moves only once during the entire rotation of the shaft 21.

[0049] The length of the cutting edge 22 is designed to at least cover the entire width of the transverse seal 3 to be cut. The cutting edge 22 is arranged parallel to the rotation axis R1 of the shaft 21.

[0050] from Figure 4bAs can be seen, the cutting edge 22 has an edge 23, which forms the radially protruding part of the blade assembly 20. The edge 23 can be planar at a microscopic level, such that the width of the edge 23 is approximately 10-30 μm. The cutting edge 22 is preferably made of carbide.

[0051] An example of the cutting board assembly 30 is in Figure 5a The -d option provides more details. For example... Figure 5a As shown, a cutting board blade 32, preferably made of carbide, is mounted to a shaft 31 such that the cutting board blade 32 extends axially along the shaft 31. Screws or bolts can be used to secure the cutting board blade 32 to the rotating shaft 31. The shaft 31 forms a circumferential surface, according to which the cutting board blade 32 protrudes radially at a specific circumferential position on the shaft 31. For the blade 22, the cutting board blade 32 moves only once during the entire rotation of the shaft 31.

[0052] The length of the cutting board blade 32 is designed to at least cover the entire width of the transverse seal 3 to be cut. The cutting board blade 32 is arranged parallel to the rotation axis R2 of the shaft 31.

[0053] from Figure 5b As can be seen, the cutting board blade 32 has a cutting board surface 33, which forms the radially protruding part of the cutting board assembly 30. The cutting board surface 33 is curved in the circumferential direction. Figure 5b As shown, the cutting board surface 33 has a radius AR. The radius AR can be in the range of 55 mm, and is preferably eccentric. The length L of the cutting board blade 32 can be approximately 45 mm, while the radius offset RO, as shown... Figure 5b As shown, it can be approximately 10 millimeters. By providing a chopping board blade 32 with a beveled shape having an off-center radius, it has been demonstrated that it is possible to control the width of the pressing area 12 to approximately 0-20 micrometers by controlling the exact position of the curved chopping board surface 33, at which the chopping board surface 33 acts together with the edge 23 of the blade 22 to form the pressing area 12.

[0054] Now for reference Figure 5c -d, the cutting board blade 32 has a first region 34 and a second region 35, such that when the first region 34 is aligned with the blade 22 at the pressure zone 12, a cut is produced, and when the second region 35 is aligned with the blade 22 at the pressure zone 12, a perforation is produced. Both regions 34 and 35 are preferably located within the cutting board surface 33, so that the cutting board surface 33 is entirely composed of the first and second regions 34 and 35. The first region 34 forms the upper part of the cutting board surface 33, while the second region 35 forms the bottom part of the cutting board surface 33.

[0055] While the first region 34 has a uniform surface, the second region 35 has multiple recesses 36. In the example shown, the recesses 36 are triangular, with the vertex of each triangle located on the boundary B between the first and second regions 34 and 35. The depth of each recess 36 increases progressively in the circumferential direction away from the first region 34 (i.e., away from the vertex). Because they are triangular, the width of each recess 36 also increases in the circumferential direction away from the first region 34.

[0056] like Figure 5c As shown, the recesses 36 in the second region 35 are arranged in a linear array. In the example shown, the linear array of recesses 36 forms a first group of recesses 36, which is spaced apart from the second group of recesses 36 in a linear direction. In each group of recesses 36, the recesses 36 are spaced apart by equal lateral / linear distances.

[0057] The structure of the cutting board blade 32, particularly the curved cutting board surface 33, is provided with a first region 34 and a second region 35, which allows for precise control of the width of the pressing area 12, as well as control over whether a cut or a puncture is produced.

[0058] Figure 6a The -d option provides a diagram illustrating this control mechanism. From... Figure 6a Initially, the cutting board assembly 30 is controlled to rotate such that the upper part of the cutting board blade 32, i.e., the upper part of the first region 34, forms a pressure zone 12 with the blade 22. In this position, the uniform surface of the first region 34 will allow for cutting of the packaging material.

[0059] By slightly altering the rotation of the cutting board assembly 30, the bottom portion of the first region 34 is aligned with the blade 22 to form the pressure zone 12 (see...). Figure 6b The width of the pressing zone is slightly increased to adjust the cutting action to accommodate slightly thicker packaging materials. This is made possible by the eccentric radius of the cutting board surface 33. A cut will be made as the first area 34 is still in motion.

[0060] Another option is Figure 6c As shown, the cutting board assembly is controlled to rotate such that the upper part of the second region 35 is aligned with the blade 22 to form a pressure zone 12. In this position, the blade 22 will act on the cutting board surface 33, which has a very small indentation (near the apex of the triangular indentation), thereby providing a first perforated pattern on the packaging material.

[0061] In addition, there are others, such as Figure 6dAs shown, the cutting board assembly 30 can be rotated so that the bottom portion of the second region 35 aligns with the blade 22 to form the pressure zone 12. The width of the pressure zone will be slightly increased to adjust the perforation action to accommodate slightly thicker packaging materials; however, since the recess 36 is wider in this position, the width of each perforation will also increase. Since the second region 35 is still in motion, one perforation will be created.

[0062] Due to the uniformly curved surface 33 of the cutting board, in Figure 6a The extreme positions indicated by -d can be continuously adjusted.

[0063] Turn now Figure 7 A method 100 will be schematically described. The purpose of performing method 100 is to provide a transverse cut and / or perforation for a string of packaged containers connected by transverse seals. The method includes a first step 102, feeding the string of packaged containers through a cutting unit such that the transverse seals of the string of packaged containers are received between a knife assembly and an anvil assembly, and a second step 104, rotating the knife assembly and anvil assembly such that the transverse seals of the string of packaged containers are received by a pressure zone formed between the blade of the knife assembly and the anvil blade of the anvil assembly. The rotation of the anvil assembly is controlled such that if a pressure zone is formed between a first region of the anvil blade and the blade, a cut is produced; and if a pressure zone is formed between a second region of the anvil blade and the blade, a perforation is produced.

[0064] As can be seen from the above description, although various embodiments of the present invention have been described and shown, the present invention is not limited thereto and may be embodied in other ways within the scope of the subject matter defined in the following claims.

Claims

1. A cutting unit (10) for providing a transversal cut and / or a perforation to a string (2) of packaging containers (1) connected by a transversal seal (3), the cutting unit (10) comprising a knife assembly (20) and an anvil assembly (30) rotatable relative to each other to form a nip (12) for receiving the transversal seal (3) of the string of packaging containers (1), characterized in that the anvil assembly (30) comprising an anvil blade (32) having a first region (34) and a second region (35) such that a cut is produced when the first region (34) is aligned with a knife edge (22) of the knife assembly (20) in the nip (12) and a perforation is produced when the second region (35) is aligned with the knife edge (22) in the nip (12), wherein the first region (34) and the second region (35) are provided on a common anvil surface (33), wherein the anvil surface (33) has an eccentric radius.

2. The cutting unit (10) according to claim 1, wherein the anvil surface (33) is curved.

3. The cutting unit (10) according to the preceding claim 1 or 2, wherein the first region (34) has a uniform surface.

4. The cutting unit (10) according to the preceding claim 1 or 2, wherein the second region (35) has a plurality of depressions (36).

5. The cutting unit (10) according to claim 4, wherein a depth of each depression (36) increases in a circumferential direction away from the first region (34).

6. The cutting unit (10) according to claim 4, wherein a width of each depression (36) increases in a circumferential direction away from the first region (34).

7. The cutting unit (10) according to claim 4, wherein each depression (36) is triangular.

8. The cutting unit (10) according to claim 4, wherein the depressions (36) are arranged in at least one linear array.

9. The cutting unit (10) according to claim 8, wherein the depressions (36) of a common array are spaced apart by an equal transversal distance.

10. The cutting unit (10) according to the preceding claim 1 or 2, further comprising a control unit (50) configured to control a rotation of the anvil assembly (30) relative to the knife assembly (20) such that the nip (12) is formed between predetermined positions of the knife edge (22) and the anvil blade (32).

11. A method of providing a transversal cut and / or a perforation to a string of packaging containers connected by a transversal seal, the method comprising: feeding the string of packaging containers through a cutting unit as defined in any one of the preceding claims 1 to 10 such that the transversal seal of the string of packaging containers is received between a knife assembly and an anvil assembly, and rotating the knife assembly and the anvil assembly such that the transversal seal of the string of packaging containers is received by a nip formed between a knife edge of the knife assembly and an anvil blade of the anvil assembly such that: if the nip is formed between the blade and a first region of the anvil, a cut is produced, and if the nip is formed between the blade and a second region of the anvil, a perforation is produced.

12. A computer program product comprising instructions for causing the cutting unit according to claim 10 to perform the steps of the method according to claim 11.

13. A computer readable medium having stored thereon the computer program product according to claim 12.

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