Cutting unit

Abstract

A cutting unit (10) is provided for providing transverse cuts and / or perforations in a series (2) of packaging containers (1) connected by transverse seals (3). The cutting unit (10) includes a knife assembly (20) and an anvil assembly (30) rotatable relative to one another to form a nip (12) for receiving the transverse seals (3) of the series (2) of packaging containers (1). The anvil assembly (30) includes an anvil blade (32) having a first region (34) and a second region (35) such that a cut is created when the first region (34) is aligned with a knife blade (22) of the knife assembly (20) at the nip (12) and a perforation is created when the second region (35) is aligned with the knife blade (22) at the nip (12). A method, a computer program, and a computer readable medium storing the computer program for providing transverse cuts and / or perforations in a series of packaging containers connected by transverse seals are also described.

Description

Technical Field

[0001] The present invention relates to a cutting unit for providing a lateral cut to packaging containers connected to each other by a lateral seal. The present invention also relates to a method for providing a lateral cut, as well as a computer program and a computer-readable recording medium.

Background Art

[0002] Carton-based packaging containers have been commercially available for many years. One example is a tetrahedral shape, which was already developed in the 1950s, and this type of packaging container has been proven to be extremely suitable for various foods such as juice beverages, milk, spread cheese, and ice candy. The general technical concept of packaging for carton-based packaging containers is to form a tube by sealing two longitudinal ends of a web of packaging material together, filling the tube with the contents to be packaged, and providing upper and lower lateral seals to the tube to seal individual packaging containers. The tetrahedral shape is obtained by providing upper and lower lateral seals substantially perpendicular to each other, and other rectangular packaging containers are obtained by arranging upper and lower lateral seals parallel to each other. During or immediately after the lateral sealing, the downstream packaging containers are separated from the upstream tube by a lateral cut near the lateral seal.

[0003] The lateral cut is provided by a cutting unit. This cutting unit has a knife that acts on an anvil, and the connected packaging containers are fed through the distance between the knife and the anvil. When the knife moves towards the anvil, the knife cuts through the lateral seal of the packaging container, thereby separating the packaging container from a series of upstream connected packaging containers.

[0004] In some packaging containers, such as the ice pops mentioned above, it is desirable to keep a certain number of individual containers connected in a chain by perforations, so that consumers can easily tear off one individual ice pop from the chain when using it. Since the chain of connected containers must have a limited length, a dedicated cutting unit is equipped with a knife and a perforation-forming tool that act alternately on the sealed chain of connected containers.

[0005] While such a solution provides the desired result of alternating cuts and perforations, it requires considerable manual adjustment to change operating parameters such as the thickness of the tube material, as well as the frequency and sequence of cuts and perforations.

[0006] Therefore, there is a need for an improved cutting unit that offers a flexible and versatile configuration, allowing the cutting unit to be easily adjusted to various cutting and perforation schemes. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] An object of the present invention is to overcome at least some of the limitations of the prior art identified above. In particular, one object is to provide a cutting unit having a rotatable anvil that, depending on the rotational position, allows the associated knife to cut or perforate the packaging material. [Means for solving the problem]

[0008] To address these objectives, a cutting unit is provided. This cutting unit is configured to provide a lateral cut and / or perforation to a series of packaging containers connected by a lateral seal. The cutting unit comprises a knife assembly and an anvil assembly rotatable relative to each other to form a nip for receiving the lateral seal of the series of packaging containers. The anvil assembly comprises an anvil blade having a first region and a second region, such that a cut is produced when the first region is aligned with the knife blade of the knife assembly at the nip, and a perforation is produced when the second region is aligned with the knife blade at the nip.

[0009] The cutting unit disclosed herein offers the advantage of being able to control whether a first or second region of the anvil blade forms a nip together with the knife blade with each rotation of the anvil assembly. This also makes it possible to determine whether a cut or a perforation should be produced with each rotation of the anvil assembly.

[0010] The first and second regions can be located on a common anvil surface. This allows for simplified control of the cutting unit's operation.

[0011] The anvil surface may be curved. Preferably, the anvil surface has an eccentric radius. Thereafter, each position on the anvil surface provides a predetermined action based on the distance of the anvil surface to the knife blade. In other words, the nip width can be controlled across the area of ​​the first and second regions.

[0012] The first region may have a uniform surface. Thus, a uniform cutting action is achieved across the entire width of the lateral seal of the packaging container.

[0013] In one embodiment, the second region has a plurality of indentations. This reduces the cutting action at the location of the indentations, resulting in perforations across the width of the lateral seal.

[0014] The depth of each groove may increase circumferentially away from the first region. This means that the level of perforation can be controlled by controlling which positions in the second region of the anvil blade form a nip together with the knife blade. Shallower grooves do not clearly distinguish between the cutting action and the perforating action, while the opposite is true for deeper grooves.

[0015] The width of each indentation may increase circumferentially away from the first region. Therefore, it is also possible to control the dimensions of the perforations, i.e., the lateral ratio of the cutting action to the perforation action.

[0016] Each recess may be triangular in shape. This thereby achieves a linear relationship between the width of the perforation action and the rotational positioning of the anvil blade.

[0017] The indentations may be arranged in at least one linear array. This creates a linear perforation, thus allowing consumers to easily tear and open the package.

[0018] The common array indentations may be spaced at equal lateral distances. This also makes it easier for the user to tear and open the document, as the force required to open the perforations is constant.

[0019] The cutting unit may further include a control unit configured to control the rotation of the anvil assembly relative to the knife assembly, so that a nip is formed between the knife blade and the anvil blade at predetermined positions. This enables automatic control of the cutting unit's operation, providing greater flexibility in defining the characteristics of the final product, i.e., a series of packaging containers.

[0020] According to a second aspect, a method is provided for providing a transverse cut and / or perforation to a series of packaging containers connected by a transverse seal. The method includes: i) feeding the series of packaging containers through a cutting unit such that the transverse seal of the series of packaging containers is received between a knife assembly and an anvil assembly; and ii) rotating the knife assembly and the anvil assembly such that the transverse seal of the series of packaging containers is received by a nip formed between a knife blade of the knife assembly and an anvil blade of the anvil assembly. A cut is produced when the nip is formed between the knife blade and a first region of the anvil blade, and a perforation is produced when the nip is formed between the knife blade and a second region of the anvil blade.

[0021] According to a third aspect, a computer program is provided. The computer program includes instructions for causing a 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 recording medium is provided. The computer-readable recording medium stores the computer program of the third aspect.

[0023] Further other objects, features, aspects, and advantages of the present invention will be apparent from the following detailed description and the drawings.

[0024] Next, embodiments of the present invention will be described by way of example with reference to the accompanying schematic drawings.

Brief Description of the Drawings

[0025] [Figure 1] It is a perspective view of a cutting unit according to an embodiment. [Figure 2] It is a cross-sectional view of the cutting unit shown in FIG. 1. [Figure 3a-b] It is a cross-sectional view showing the relative positions of the knife and the anvil during the operation of the cutting unit. [Figure 4a] A perspective view of a knife assembly forming part of a cutting unit. [Figure 4b] A side view of a knife blade forming part of the knife assembly shown in FIG. 4a. [Figure 5a] A perspective view of an anvil assembly forming part of a cutting unit. [Figure 5b] A side view of an anvil blade forming part of the anvil assembly shown in FIG. 5a. [Figure 5c] A perspective view of an anvil blade according to one embodiment. [Figure 5d] A cross-sectional view of the anvil blade shown in FIG. 5c. [Figure 6a-d] A cross-sectional view of various operations of a cutting unit. [Figure 7] A schematic view of a method according to one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Referring to FIG. 1, a cutting unit 10 is shown. The cutting unit 10 typically forms part of a roll-fed packaging machine configured to form, fill, and seal individual packaging containers 1 by transforming a web of packaging material into a longitudinally sealed tube. The tube is partially filled with its intended contents and then a transverse seal is provided to the tube, forming a series 2 of packaging containers 1 connected to each other by the transverse seal 3. This process is well known in the art and commercially successful by AB Tetra Pak.

[0027] The cutting unit 10 is positioned at a predetermined location of the packaging machine to receive a series 2 of packaging containers 1. As can be seen from FIG. 1, the purpose of the cutting unit 10 is to make a cut in the series 2 at the location of the transverse seal 3, whereby one or more packaging containers 1 are separated from the upstream series 2. However, as will be further explained below, the cutting unit 10 can also provide perforations to the series 2.

[0028] The cutting unit 10 comprises a knife assembly 20 and an anvil assembly 30. The knife assembly 20 is rotationally driven by a first motor 40a. Similarly, the anvil assembly is rotationally driven by a second motor 40b. The first and second motors 40a and 40b are preferably servo motors, enabling precise rotational control of the knife assembly 20 and the anvil assembly 30.

[0029] The control unit 50 forms part of the cutting unit 10 and is programmed to provide control signals for 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 by a pivot point 60. A spring 62 applies a spring force between the knife assembly 20 and the anvil assembly 30 to allow for precise positioning of the knife assembly and the anvil assembly.

[0030] The cutting unit 10 is preferably positioned horizontally and is therefore capable of receiving a series of 2 packaging containers 1 moving vertically.

[0031] Figure 2 shows a cross-sectional view of the cutting unit 10. The knife assembly 20 includes a rotating shaft 21 driven by a motor 40a. The rotating shaft 21 has a knife blade 22. Similarly, the anvil assembly 30 includes a rotating shaft 31 driven by a motor 40b. The rotating shaft 31 has an anvil blade 32.

[0032] As shown in Figure 2, the knife blade 22 and the anvil blade 32 define the nip 12 when they are positioned opposite each other. When a series 2 of packaging containers 1 is received by the nip 12, a cut or perforation is created. Thus, by controlling the rotation of the knife assembly 20 and the anvil assembly 30, it is also possible to determine where in the series 2 the cut / perforation should be made.

[0033] Figure 3a shows a more detailed cross-sectional view of the cutting unit 10. To further enhance the understanding of the operation of the cutting unit 10, the sequence 2 is schematically shown.

[0034] As illustrated, the rotating shafts 21 and 31 are similar in shape and have polygonal cross-sections. The shape of the rotating shafts 21 and 31 allows each shaft 21 and 31 to change its lateral distance relative to the anvil blade 2 as the shafts 21 and 31 rotate. Thus, in the rotational position shown in Figure 3a, the shafts 21 and 31 provide a minimum distance between themselves and thereby form a nip 12. Preferably, in this position, the knife blade 22 does not make full contact with the anvil blade 32. As an example, the nip 12 can be formed by a lateral distance of about 5 to 20 μm between the knife blade 22 and the anvil blade 32. This is particularly advantageous for packaging materials having a core layer of carton-based material, because such materials would tear due to the sudden compressive force generated at the nip 12, thereby causing a subsequent cutting action. Nevertheless, since there is no actual contact between the knife blade 22 and the anvil blade 32, wear on the knife blade 22 is greatly reduced.

[0035] As shafts 21 and 31 continue to rotate in the direction shown in Figure 3a, the knife blade 22 and anvil blade 32 move further away from each other. The non-circular shape of shafts 21 and 31 also increases the lateral distance between shafts 21 and 31, thereby allowing the chain 2 to pass through the cutting unit 10.

[0036] Such positions of the knife assembly 20 and the anvil assembly 30 are shown in Figure 3b, from which it is clear that the chain 2 can pass through without being compressed by the shafts 21 and 31. When the shafts 21 and 31 return to their minimum relative distance in Figure 3a, the nip 12 is formed again, thereby creating a cut or perforation in the packaging container 1 of the clamped chain 2.

[0037] Each end of the respective rotating shafts 21 and 31 is provided with rings 21a-b and 31a-b. The rings 21a-b of the knife assembly 20 are fixed, while the rings 31a-b of the anvil assembly have bearings. During the assembly of the cutting unit 100, the rings 21a-b and 31a-b are pressed against each other by a spring 62 (see Figure 1) with a force of approximately 2-5 kN. Since the anvil assembly 30 has bearings inside the rings 31a-b, rotational control of the anvil assembly 30 relative to the knife assembly 20 is still possible.

[0038] An example of the knife assembly 20 is shown in more detail in Figures 4a and 4b. As shown in Figure 4a, the knife blade 22 is attached to the shaft 21 so as to extend along the shaft 21 in the axial direction of the shaft 21. The knife blade 22 can be secured to the rotating shaft 21 using screws or bolts. The shaft 21 forms a circumferential surface, and the knife blade 22 protrudes radially at one specific circumferential position on the shaft 21. Thus, the knife blade 22 acts only once during one full rotation of the shaft 21.

[0039] The length of the knife blade 22 is designed to cover at least the entire width of the lateral seal 3 to be cut. The knife blade 22 is positioned parallel to the axis of rotation R1 of the shaft 21.

[0040] As can be seen in Figure 4b, the knife blade 22 has an edge 23 that forms the maximum radial projection of the knife assembly 20. The edge 23 is planar at a microscopic level, and its width is approximately 10 to 30 μm. The knife blade 22 is preferably formed from carbide.

[0041] Examples of anvil assemblies 30 are shown in more detail in Figures 5a-5d. As shown in Figure 5a, an anvil blade 32, preferably formed from carbide, is attached to the shaft 31 so as to extend along the shaft 31 in the axial direction of the shaft 31. The anvil blade 32 can be secured to the rotating shaft 31 using screws or bolts. The shaft 31 forms a circumferential surface, and the anvil blade 32 protrudes radially at one specific circumferential position on the shaft 31. Thus, as with the knife blade 22, the anvil blade 32 acts only once during one full rotation of the shaft 31.

[0042] The length of the anvil blade 32 is designed to cover at least the entire width of the lateral seal 3 to be cut. The anvil blade 32 is positioned parallel to the axis of rotation R2 of the shaft 31.

[0043] As can be seen in Figure 5b, the anvil blade 32 has an anvil surface 33 that forms the maximum radial projection of the anvil assembly 30. The anvil surface 33 is curved in the circumferential direction. As shown in Figure 5b, the anvil surface 33 has a radius AR. The radius AR, which may be about 55 mm, is preferably eccentric. The length L of the anvil blade 32 may be about 45 mm, and the radius offset RO shown in Figure 5b may be about 10 mm. By providing an anvil blade 32 having a slope shape with an eccentric radius, it has been demonstrated that the width of the nip 12 can be controlled to about 0 to 20 μm by controlling the precise position of the curved anvil surface 33 that acts to form the nip 12 together with the edge 23 of the knife blade 22.

[0044] Next, referring to Figures 5c to 5d, the anvil blade 32 has a first region 34 and a second region 35, where a cut is generated when the first region 34 is aligned with the knife blade 22 at the nip 12, and a perforation is generated when the second region 35 is aligned with the knife blade 22 at the nip 12. Preferably, both regions 34 and 35 are located within the anvil surface 33, and the anvil surface 33 is entirely composed of the first and second regions 34 and 35. The first region 34 forms the upper portion of the anvil surface 33, and the second region 35 forms the lower portion of the anvil surface 33.

[0045] The first region 34 has a uniform surface, and the second region 35 has a plurality of depressions 36. In the illustrated example, the depressions 36 are triangular in shape, with the vertices of each triangle located at the boundary B between the first and second regions 34, 35. The depth of each depression 36 increases in the circumferential direction away from the first region 34, i.e., away from the vertices. Due to this triangular shape, the width of each depression 36 also increases in the circumferential direction away from the first region 34.

[0046] As shown in Figure 5c, the depressions 36 of the second region 35 are arranged in a linear array. In the illustrated example, the linear array of depressions 36 forms a first set of depressions 36 that are linearly separated from a second set of depressions 36. In each set of depressions 36, the depressions 36 are separated by an equal lateral / linear distance.

[0047] The configuration of the anvil blade 32, particularly the curved anvil surface 33 having a first region 34 and a second region 35, allows for precise control of the width of the nip 12 and control over whether to produce a cut or a perforation.

[0048] A schematic diagram of such control is shown in Figures 6a to 6d. Starting from Figure 6a, the anvil assembly 30 is controlled to rotate such that the upper part of the anvil blade 32, i.e., the upper portion of the first region 34, together with the knife blade 22 forms a nip 12. In this position, the uniform surface of the first region 34 allows for the cutting of the packaging material.

[0049] By controlling the rotation of the anvil assembly 30 in a slightly different manner, and instead aligning the lower portion of the first region 34 with the knife blade 22 to form a nip 12 (see Figure 6b), the nip width is slightly increased, adjusting the cutting action to accommodate slightly thicker packaging materials. This is made possible by the eccentric radius of the anvil surface 33. A cut is produced as the first region 34 is still working.

[0050] Another option is shown in Figure 6c, in which the anvil assembly is controlled to rotate so that the upper portion of the second region 35 aligns with the knife blade 22 to form a nip 12. In this position, the knife blade 22 acts against the anvil surface 33, which has a very small recess (near the apex of the triangular recess), to provide a first perforation pattern to the packaging material.

[0051] Furthermore, as shown in Figure 6d, the anvil assembly 30 can be controlled to rotate so that the lower portion of the second region 35 aligns with the knife blade 22 to form a nip 12. The nip width is slightly increased to adjust the perforation action to accommodate slightly thicker packaging material, but the width of each perforation is also increased because the width of the recess 36 is wider in this position. Perforations are generated as the second region 35 is still in operation.

[0052] The uniformly curved anvil surface 33 allows for continuous adjustment between the two extreme positions shown in Figures 6a to 6d.

[0053] Next, referring to Figure 7, Method 100 is schematically described. Method 100 is performed to provide a lateral cut and / or perforation to a series of packaging containers connected by a lateral seal. The method includes a first step 102 of feeding the series of packaging containers through a cutting unit so that the lateral seal of the series of packaging containers is received between the knife assembly and the anvil assembly, and a second step 104 of rotating the knife assembly and the anvil assembly so that the lateral seal of the series of packaging containers is received by a nip formed between the knife blade of the knife assembly and the anvil blade of the anvil assembly. The rotation of the anvil assembly is controlled so that a cut is produced if the nip is formed between the knife blade and a first region of the anvil blade, and a perforation is produced if the nip is formed between the knife blade and a second region of the anvil blade.

[0054] Although various embodiments of the present invention have been described and illustrated, the present invention is not limited thereto and can be embodied in other forms within the scope of the subject matter defined in the following claims.

Claims

1. A cutting unit (10) for providing lateral cuts and / or perforations to a series (2) of carton-based packaging containers (1) connected by lateral seals (3), comprising a knife assembly (20) and an anvil assembly (30) rotatable relative to each other to form a nip (12) for receiving the lateral seals (3) of the series (2) of carton-based packaging containers (1), The anvil assembly (30) comprises an anvil blade (32) having a first region (34) and a second region (35), wherein a cut is generated when the first region (34) is aligned with the knife blade (22) of the knife assembly (20) at the nip (12), and a perforation is generated when the second region (35) is aligned with the knife blade (22) at the nip (12). The anvil blade (32) comprises an anvil surface (33), the anvil surface (33) is curved in the circumferential direction, The anvil surface (33) has an eccentricity radius. Cutting unit (10).

2. The cutting unit (10) according to claim 1, wherein the first and second regions (34, 35) are arranged on a common anvil surface (33).

3. The anvil assembly (30) comprises a rotating shaft (31) driven to rotate about a rotation axis (R2), and substantially circular rings (31a, 31b) attached to the rotating shaft (31), The rotating shaft (31) has the anvil blade (32), and the anvil blade (32) is configured to act only once during one rotation of the rotating shaft (31). The cutting unit (10) according to claim 1 or 2.

4. The anvil surface (33) forms the maximum radial projection of the anvil assembly (30). A cutting unit (10) according to any one of claims 1 to 3.

5. The cutting unit (10) according to any one of claims 1 to 4, wherein the first region (34) has a uniform surface.

6. The cutting unit (10) according to any one of claims 1 to 5, wherein the second region (35) has a plurality of recesses (36).

7. The cutting unit (10) according to claim 6, wherein the depth of each recess (36) increases in the circumferential direction away from the first region (34).

8. The cutting unit (10) according to claim 6 or 7, wherein the width of each recess (36) increases in the circumferential direction away from the first region (34).

9. The cutting unit (10) according to any one of claims 6 to 8, wherein each recess (36) is triangular in shape.

10. The cutting unit (10) according to any one of claims 6 to 9, wherein the recesses (36) are arranged in at least one linear array.

11. The cutting unit (10) according to claim 10, wherein the recesses (36) of the common array are spaced apart by equal lateral distances.

12. The cutting unit (10) according to any one of claims 1 to 11, further comprising a control unit (50) configured to control the rotation of the anvil assembly (30) relative to the knife assembly (20), wherein the nip (12) is formed between the knife blade (22) and the anvil blade (32) at a predetermined position.

13. A method for providing lateral cuts and / or perforations in a series of carton-based packaging containers connected by lateral seals, The steps include feeding the series of carton-based packaging containers through a cutting unit so that the lateral seal of the series of carton-based packaging containers is received between the knife assembly and the anvil assembly, The step includes rotating the knife assembly and the anvil assembly so that a nip formed between the knife blade of the knife assembly and the anvil blade of the anvil assembly allows the lateral seal of the series of carton-based packaging containers to be received. The anvil blade comprises an anvil surface, the anvil surface is curved in the circumferential direction, and the anvil surface (33) has an eccentricity radius. When the nip is formed between the knife blade and the first region of the anvil blade, a cut is generated. If the nip is formed between the knife blade and the second region of the anvil blade, a perforation is generated. method.

14. A computer program comprising an instruction causing the cutting unit described in claim 12 to perform a step of the method described in claim 13.

15. A computer-readable recording medium having the computer program described in claim 14 stored on it.

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