Unit and method for forming, starting from a sheet of packaging material, a tube for the production of sealed packages

Abstract

A unit (1) is described, configured to produce a sealed package (3) from a packaging material sheet (4) having an opening device (5) pre-applied thereto. The unit includes at least one guide assembly (10) configured to interact with the packaging material sheet (4) to progressively fold it into a tubular shape. The guide assembly (10) includes a plurality of folding rollers (11, 13) defining channels (50) for the packaging material sheet (4), and each folding roller (11, 13) has a sidewall (11a) configured to contact and cooperate with the packaging material sheet (4) to control its folding. The folding rollers (11, 13) include at least one folding roller (13) having at least one recess on its sidewall (11a), the recess defining a groove (14) configured to engage with the opening device (5).

Description

Technical Field

[0001] The present invention relates to a unit configured to form a tube for producing sealed packaging (preferably containing pourable products, particularly pourable food) from a packaging material sheet, wherein the packaging material sheet has an opening device pre-applied thereon, particularly an opening device pre-molded thereon.

[0002] The present invention also relates to a method for forming a tube for producing sealed packaging (preferably containing a pourable product, particularly a pourable food) from a packaging material sheet, wherein the packaging material sheet has an opening device pre-applied thereon, particularly an opening device pre-molded thereon. Background Technology

[0003] As is well known, many pourable foods, such as fruit juice, UHT (ultra-high temperature) milk, wine, and ketchup, are sold in packages made of sterilized packaging materials.

[0004] A typical example is the parallelepiped packaging used for pourable foods, called Tetra Pak aseptic (registered trademark), which is made by laminating webs of packaging material through folding and sealing. The packaging material has a multi-layered structure, including a base layer, for example, made of paper; the base layer is covered on both sides with heat-sealable plastic material layers, such as polyethylene. For aseptic packaging of products intended for long-term storage (e.g., UHT milk), the packaging material also includes an oxygen barrier layer, such as aluminum foil, which is stacked on top of a heat-sealable plastic material and then covered by another heat-sealable plastic material layer forming the inner surface of the packaging that ultimately comes into contact with the food.

[0005] This type of packaging is typically produced in a fully automated packaging assembly, in which a continuous tube is formed from a web of packaging material unwound from a reel and fed into the assembly. The web of packaging material is sterilized within the assembly, for example by applying a chemical sterilizing agent (e.g., hydrogen peroxide solution); once sterilization is complete, the applied chemical sterilizing agent is removed from the surface of the packaging material, for example by heating and evaporation. The thus sterilized web is then held in a closed sterilization environment and folded and longitudinally sealed to form a tube that is fed in a vertical direction of travel.

[0006] To complete the forming process, the tube is filled from above with sterilized food and sealed, and then cut along equally spaced transverse sections through known forming and sealing units.

[0007] This results in a pillow-shaped package with a longitudinal sealing strip, a top transverse sealing strip, and a bottom transverse sealing strip.

[0008] Known packaging components typically include a folding unit configured to be fed together with a pillow-shaped package to form a fully folded finished package.

[0009] In order to form a tube, the web of packaging material is fed through multiple guiding components that interact with the packaging material to gradually fold it from sheet form into a tube shape.

[0010] The guiding components are arranged in succession and include their respective folding members, which define multiple forced channels for the packaging material, the cross-section of which gradually changes from C-shaped to approximately circular.

[0011] Specifically, each guide assembly includes multiple folding rollers that define folding members and rotate about a rotation axis arranged in a common plane (typically a horizontal plane).

[0012] When interacting with the folding roller, the first longitudinal edge of the packaging material sheet gradually approaches and then overlaps the second longitudinal edge of the packaging material sheet opposite to the first longitudinal edge, until one of the two longitudinal edges overlaps the other radially relative to the tube axis.

[0013] Then, the first and second longitudinal edges are sealed together, for example by heat sealing, to form a longitudinal sealing strip along the tube (i.e., substantially parallel to the tube axis).

[0014] At this point, the tube can be filled with a pourable product, then formed, laterally sealed, and cut to obtain the aforementioned pillow-shaped packaging.

[0015] Various solutions have been proposed to open the aforementioned packaging, including the use of opening devices made of plastic materials.

[0016] According to the first solution, the opening device is known to be directly molded onto the so-called pre-laminated hole by injection molding, which is a hole formed only by the base layer and covered by other laminated layers of packaging material (including gas barrier material layers) through a lamination process.

[0017] In other words, molten plastic material is molded, in particular, injection molded into and through the cover portion of the pre-laminated holes made of this laminated layer.

[0018] According to alternative solutions, this covering can be defined by a patch attached to the packaging material to close (in this case) the hole formed through the entire thickness of the packaging material.

[0019] According to the alternative solution, holes are formed through the entire thickness of the packaging material, in particular by punching, and then the opening device is molded onto them.

[0020] Therefore, in the above scheme, the packaging material sheet is provided with an opening device pre-applied to it before it is forced through the guide assembly.

[0021] During the process of forming a tube from a sheet of packaging material with a pre-applied opening device, the opening device may interfere with or collide with one of the folding rollers (especially the folding roller in the trajectory of the opening device).

[0022] One known solution is to remove the folding roller, thereby freeing up the channel used to open the device through the guide component.

[0023] However, for certain types of packaging, such as small-sized packaging, like single-serving packaging, the above solution has some drawbacks.

[0024] In fact, the overlap area is defined when the first longitudinal edge overlaps the second longitudinal edge. Controlling the extension (i.e., width) of the overlap area is extremely important to ensure a good longitudinal seal of the tube and the correct weight of the package being formed.

[0025] The applicant has observed that if the ratio between the diameter of the tube and the size of the opening device is very small, removing one of the folding rollers may damage the optimal overlap between the first and second longitudinal edges of the packaging material sheet.

[0026] In practice, the removal of a folding roller may cause the tube to bulge radially in the area where the folding roller was removed.

[0027] Furthermore, since the operations of forming the tube and the longitudinal sealing tube are carried out continuously, it is extremely important to keep the extension of the overlapping area as constant as possible during the work cycle of the packaging assembly. Summary of the Invention

[0028] Therefore, one object of the present invention is to provide a unit configured to form a tube for producing sealed packaging from a sheet of packaging material having an opening device pre-applied thereon, which is designed to overcome at least one of the aforementioned disadvantages in a direct and low-cost manner.

[0029] This objective is achieved by the unit according to claim 1.

[0030] Another object of the present invention is to provide a method for forming a tube for producing a sealed package from a sheet of packaging material having an opening device pre-applied thereon, which allows overcoming at least one of the aforementioned disadvantages in a direct and low-cost manner.

[0031] This objective is achieved by the method according to claim 11. Attached Figure Description

[0032] Non-limiting embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0033] Figure 1This is a perspective view of a packaging assembly for producing sealed packaging according to the present invention, wherein parts have been removed for clarity, the packaging assembly comprising units configured to form tubes for producing such packaging from a sheet of packaging material;

[0034] Figure 2 yes Figure 1 An enlarged perspective view of the unit, with some parts removed for clarity;

[0035] Figure 3 yes Figure 2 A partial sectional side view of the unit, wherein parts have been removed for clarity; and

[0036] Figure 4 yes Figure 2 A partial cutaway top view of the unit, where parts have been removed for clarity. Detailed Implementation

[0037] refer to Figure 1 The number 1 represents a unit as a whole, which is configured to form a tube 2 for producing a sealed package 3 from a mesh packaging material sheet 4 with a pre-applied opening device 5 (in particular, a packaging material sheet 4 with an opening device 5 pre-molded thereon). Preferably, the package 3 contains a pourable product, particularly a pourable food, such as pasteurized or UHT milk, juice, wine, peas, beans, etc.

[0038] Unit 1 is part of a known packaging assembly 100 for the continuous production of packaging 3 from packaging material sheet 4, which is unrolled from a reel 6 and fed along a forming path P.

[0039] The packaging material has a multi-layer structure (not shown) and includes a fibrous material layer, such as a paper layer, which is covered on both sides with corresponding heat-sealable plastic material layers, such as polyethylene layers.

[0040] In the case of aseptic packaging 3 for long-term storage products (e.g., UHT milk), the packaging material also includes a gas and light barrier material layer (e.g., aluminum foil or ethylene vinyl alcohol (EVOH) film) which is superimposed on a heat-sealed plastic material layer and covered by another heat-sealed plastic material layer that forms the inner surface of the packaging 3 that ultimately contacts the pourable product.

[0041] After being unrolled from the roll 6 and before entering the unit 1, the packaging material sheet 4 is sterilized, for example by applying a chemical sterilizing agent, such as hydrogen peroxide solution; once sterilization is complete, the applied chemical sterilizing agent is removed from the surface of the packaging material, for example by heating and evaporation. The packaging material sheet 4 is also equipped with multiple opening devices 5. Figure 2 , 3 and 4).

[0042] According to this non-limiting embodiment, the opening device 5 is made of a plastic material that is injection molded onto the packaging material sheet 4 along the forming path P by a known molding device (not shown) arranged downstream of the reel 6 and upstream of the unit 1.

[0043] Specifically, the opening device 5 is molded onto the packaging material sheet 4 along a substantially straight application strip and at substantially the same distance L between each other, in particular the same straight-line distance L.

[0044] It is hereby stated that the term "substantially" is used in this specification to take into account the normal tolerances that may exist between the components of unit 1 and packaging assembly 100.

[0045] like Figure 1 As can be seen, the packaging material sheet 4 is fed along the forming path P by the guide member 7 (e.g., a roller or similar).

[0046] The packaging assembly 100 also includes known forming and sealing devices, such as clamp units (not shown) arranged downstream of unit 1 and configured to clamp, form, laterally seal and cut tube 2 along equally spaced cross sections to obtain pillow-shaped packaging 3a.

[0047] The pillow-shaped packages 3a are then fed into a folding unit (not shown), which is configured to fold them into finished packages 3.

[0048] Unit 1 includes a folding assembly 8 for gradually folding the packaging material sheet 4.

[0049] The folding assembly 8 includes a plurality of guide assemblies 10 (two in the preferred embodiment shown) arranged continuously along the forming path P and configured to interact with the packaging material sheet 4 to gradually fold it into a tubular shape, thereby obtaining the tube 2.

[0050] Specifically, each guide assembly 10 includes a plurality of folding rollers 11 rotatably mounted on the respective guide assembly 10 about a corresponding axis of rotation, defining a channel 50 for the packaging material sheet 4 (i.e., for the tube 2 being formed). Figure 4 ), and is configured to interact with the packaging material sheet 4.

[0051] In detail, each folding roller 11 has a sidewall 11a that is configured to contact the packaging material sheet 4 to control its folding.

[0052] More specifically, when the packaging material sheet 4 is pulled through the channel 50 by the action of the clamping unit during use, the sidewall 11a of the folding roller 11 interacts with the packaging material sheet 4, thereby forming the packaging material sheet 4 into a tube 2.

[0053] More precisely, in a known but not detailed manner, the folding roller 11 is configured to contact and cooperate with the packaging material sheet 4 such that its first longitudinal edge 4a overlaps its second longitudinal edge 4b, which is opposite to the first longitudinal edge 4a, to define an overlap area 12 of the first longitudinal edge 4a and the second longitudinal edge 4b.

[0054] In other words, the folding roller 11 forms the tube 2 in such a way that the first longitudinal edge 4a is located outside the second longitudinal edge 4b ​​relative to the axis A of the tube 2. Figure 4 ).

[0055] Unit 1 also includes a sealing station (not shown) comprising a sealing device, preferably a heating device, configured to heat the first longitudinal edge 4a and partially melt the polyethylene layer of the first longitudinal edge 4a.

[0056] Heat is transferred from the first longitudinal edge 4a to the second longitudinal edge 4b ​​through conduction, thereby causing the polyethylene layer of the second longitudinal edge 4b ​​to melt locally.

[0057] Then the first longitudinal edge 4a and the second longitudinal edge 4b ​​are pressed together to obtain a longitudinal seal that is substantially parallel to axis A.

[0058] At this point, the tube 2 can be filled with a pourable product (preferably from above).

[0059] As can be seen in the attached figure, the channel 50 defined by the folding roller 11 is coaxial with shaft A.

[0060] Preferably, the rotation axis of the folding roller 11 of a guide assembly 10 is arranged on a corresponding common plane.

[0061] Specifically, the two guide components 10 are arranged on different planes that are continuously arranged along the forming path P.

[0062] In the illustrated embodiment, these planes are horizontal and parallel to each other, and axis A is vertical.

[0063] Therefore, in use, the packaging material sheet 4 first interacts with the upper guide assembly 10, which causes the first longitudinal edge 4a to approach the second longitudinal edge 4b, thereby folding the packaging material sheet 4 into a generally C-shape.

[0064] Then, the folded packaging material sheet 4 interacts with the lower guide assembly 10, which determines the creation of the overlap area 12 and causes the C-shaped packaging material sheet 4 to fold into a tubular shape.

[0065] In view of the above, during the folding process of the packaging material sheet 4, and therefore during the formation process of the tube 2, the folding roller 11 surrounds the packaging material sheet 4.

[0066] Since the packaging material sheet 4 is provided with an opening device 5 that is pre-applied to it along the application belt, such opening device 5 may collide with one of the folding rollers 11 that surround the packaging material sheet 4 and define the channel 50.

[0067] One solution to this problem requires removing the folding roller 11 located in the track of the opening device 5 through the channel 50.

[0068] However, as stated above, the applicant has observed that, in the case of small-sized packaging 3, i.e., in the case of tube 2 with a small diameter, this removal may impair the optimal overlap between the first longitudinal edge 4a and the second longitudinal edge 4b ​​at the overlapping area 12.

[0069] Advantageously, the folding roller 11 includes at least one folding roller 13 having at least one recess on its sidewall 11a that defines a groove 14 configured to engage with the opening device 5.

[0070] Preferably, the folding roller 13 has a plurality of grooves 14 on its sidewall 11a to define an alternation of solids and voids on the sidewall 11a, each void being defined by a corresponding groove 14.

[0071] In detail, the folding roller 13 defines a gear 15, which includes a plurality of teeth 16 defining the aforementioned solid.

[0072] Furthermore, the tooth 16 is configured to selectively engage with the opening device 5, thereby driving the wheel 15 to rotate by the movement of the packaging material sheet 4 through the channel 50.

[0073] In view of the above, the packaging material sheet 4 drives the wheel 15 (i.e., rotates the wheel 15), namely the folding roller 13, through the opening device 5 that engages with the corresponding groove 14 and meshes with the corresponding tooth 16.

[0074] More specifically, the opening device 5 engages with the corresponding side of the tooth 16, such as Figure 3 As specifically shown in the text.

[0075] Furthermore, the teeth 16, particularly the upper surface of the teeth 16, define a corresponding portion of the sidewall 11a of the folding roller 13, which is configured to cooperate in contact with the packaging material sheet 4, especially as Figure 2 and 3 As shown.

[0076] Preferably, the folding roller 13 is rotatable about a rotation axis B, which is located on the same common plane as the rotation axes of the other folding rollers 11 of the same guide assembly 10 (i.e., the lower guide assembly 10).

[0077] In particular, axis B is orthogonal to axis A.

[0078] Due to the presence of the folding roller 13, i.e. the wheel 15, optimal overlap of the first longitudinal edge 4a with the second longitudinal edge 4b ​​can be achieved in the overlapping area 12, as the alternation of solids and voids (i.e., teeth 16 and grooves 14) provides radial support for the packaging material sheet 4, while allowing the opening device 5 to pass freely through the channel 50.

[0079] In other words, tooth 16 prevents bulging of the packaging material sheet 4 (i.e., the tube 2 being formed), i.e., displacement in the radial direction relative to axis A, which would compromise the optimal overlap obtained at the overlapping area 12.

[0080] At the same time, each slot 14 provides space for the opening device 5, which is pre-applied to the packaging material sheet 4, to freely pass through the channel 50, thereby avoiding any collisions in the radial direction.

[0081] According to the preferred embodiment shown, only one of the guide components 10 (particularly the lower guide component 10) is provided with a folding roller 13.

[0082] Accordingly, the upper guide assembly 10 does not have a folding roller 11, so that the opening device 5 can freely pass through the relevant channel 50.

[0083] As described above, the opening device 5 is pushed onto the corresponding tooth 16, causing the wheel 15 to rotate.

[0084] Therefore, advantageously, the folding roller 13 (i.e., wheel 15) is an idle roller, that is, it is passively driven to rotate.

[0085] Furthermore, the above configuration provides self-synchronizing meshing. In fact, if a certain amount of delay accumulates in the nominal meshing between the folding roller 13 and the opening device 5 relative to the tooth 16, the opening device 5 itself will act on the corresponding tooth 16, particularly on the aforementioned side of the tooth 16, thereby ensuring self-synchronization.

[0086] To ensure that the delay between the slot 14 and the opening device 5 is as small as possible (so that the delay recovery is the fastest), it is convenient to provide a large number of slots 14 for the folding roller 13.

[0087] Conveniently, the distance between two consecutive grooves 14 or between two consecutive teeth 16, measured on the outer periphery of the sidewall 11a of the folding roller 13, is equal to the distance L divided by an integer.

[0088] Specifically, the aforementioned distance is the bending distance measured on the outer periphery of the folding roller 13, that is, the distance is defined by the circumferential arc.

[0089] Therefore, the folding roller 13 includes any number of grooves 14 and teeth 16, as long as the distance between two consecutive grooves 14 or two consecutive teeth 16 measured on the outer periphery of the sidewall 11a of the folding roller 13 is equal to the distance L divided by an integer.

[0090] According to an embodiment not shown, unit 1 may include an actuating device (not shown), such as a motor, operatively coupled to the folding roller 13 and configured to selectively control the rotation of the folding roller 13 about axis B. For example, the actuating device may control the rotation of the folding roller 13 to restore the delay in engagement between the teeth 16 and the opening device 5.

[0091] Preferably, the grooves 14 are equidistant from each other along the sidewall 11a. Therefore, the teeth 16 are also equidistant from each other along the sidewall 11a.

[0092] Therefore, the solids and voids mentioned above alternate regularly.

[0093] The operation of unit 1 is described below, starting from the state where the packaging material sheet 4 has interacted with the upper guide assembly 10 and is moving toward the lower guide assembly 10 where the folding roller 13 is located.

[0094] At this time, the packaging material sheet 4 interacts with the folding roller 11 of the lower guide assembly 10 and with the folding roller 13, and advances through the channel 50.

[0095] Therefore, the opening device 5 sequentially engages the corresponding groove 14 of the folding roller 13 and meshes with its teeth 16, thereby driving the folding roller 13 (i.e., wheel 15) and causing it to rotate around the shaft B.

[0096] In this way, the overlap of the first longitudinal edge 4a and the second longitudinal edge 4b ​​is achieved and maintained at the overlap area 12, while the opening device 5 can pass freely through the channel 50 without obstruction.

[0097] Pipe 2 is thus formed, longitudinally sealed, and filled from above with a pourable product in a known but not detailed manner.

[0098] Then tube 2 is fed into clamp-type unit arranged downstream of unit 1 to form, laterally seal and cut along equally spaced cross sections to obtain pillow-shaped package 3a.

[0099] The pillow-shaped packages 3a are then fed into a folding unit configured to fold them into finished packages 3.

[0100] The above operations are performed continuously throughout the entire working cycle of the packaging component 100.

[0101] From the foregoing description, the advantages of unit 1 according to the present invention will become clear.

[0102] In particular, due to the configuration of the folding roller 13 (i.e., wheel 15), optimal overlap of the first longitudinal edge 4a with the second longitudinal edge 4b ​​in the overlapping area 12 can be achieved, because the alternation of solids and gaps (i.e., teeth 16 and slits 14) provides radial support for the packaging material sheet 4, while allowing the opening device 5 to pass freely through the channel 50.

[0103] In other words, the tooth 16 prevents the packaging material sheet 4 (i.e. the tube 2 being formed) from bulging, i.e., displacement in the radial direction relative to the axis A, thereby ensuring that the extension of the overlapping area 12 remains as constant as possible during the working cycle of the packaging assembly 100.

[0104] Therefore, a unit 1 is provided for optimizing the production of small-sized packages 3 starting from a packaging material sheet 4 having a pre-applied opening device 5.

[0105] Obviously, unit 1 described herein can be modified without departing from the scope of protection defined by the appended claims.

Claims

1. A unit (1) configured to produce a sealed package (3) from a packaging material sheet (4) having an opening device (5) pre-applied thereto, the unit comprising at least one guide assembly (10) configured to interact with the packaging material sheet (4) to progressively fold it into a tubular shape; The guiding assembly (10) includes a plurality of folding rollers (11, 13) defining channels (50) for the packaging material sheet (4), and each folding roller (11, 13) has a sidewall (11a) configured to contact and cooperate with the packaging material sheet (4) to control its folding. characterized in that The folding rollers (11, 13) include at least one folding roller (13) having at least one recess on its sidewall (11a), the recess defining a groove (14) configured to engage with the opening device (5); The at least one folding roller (13) has a plurality of the grooves (14) on its sidewall (11a) to define an alternation of solids and voids on the sidewall (11a).

2. The unit according to claim 1, wherein the grooves (14) are equidistant from each other along the sidewall (11a).

3. The unit according to claim 1 or 2, wherein the at least one folding roller (13) defines a gear (15) comprising a plurality of teeth (16) defining the solid and configured to selectively engage with the opening device (5).

4. The unit according to claim 3, wherein the tooth (16) defines a portion of the sidewall (11a) of the at least one folding roller (13) configured to cooperate in contact with the packaging material sheet (4).

5. The unit according to claim 1, 2 or 4, wherein the distance between two consecutive grooves (14) or between two consecutive solids measured on the outer periphery of the sidewall (11a) of the at least one folding roller (13) is equal to the distance (L) between two consecutive opening devices (5) on the packaging material sheet (4) divided by an integer.

6. The unit according to claim 5, wherein the distance between two consecutive grooves (14) or between two consecutive solids measured on the outer periphery of the sidewall (11a) of the at least one folding roller (13) is equal to the straight distance (L) between two consecutive opening devices (5) on the packaging material sheet (4) divided by an integer.

7. The unit according to claim 1, 2, 4 or 6, wherein the folding roller (11) is rotatable about a first rotation axis arranged on a common plane; and wherein the at least one folding roller (13) is rotatable about a second rotation axis (B) arranged on the same common plane.

8. The unit according to any one of claims 1, 2, 4 or 6 further includes an actuation device operatively coupled to the at least one folding roller (13) and configured to selectively control the rotation of the at least one folding roller (13) about its own axis of rotation (B).

9. The unit according to claim 1, 2, 4 or 6, wherein the channel has a longitudinal axis; and the at least one folding roller (13) has a rotation axis orthogonal to the longitudinal axis.

10. The unit according to claim 1, 2, 4 or 6, wherein the folding roller (11, 13) is configured to contact and cooperate with the packaging material sheet (4) such that its first longitudinal edge (4a) overlaps its second longitudinal edge (4b) opposite to the first longitudinal edge (4a) to define an overlap area (12) of the first longitudinal edge (4a) and the second longitudinal edge (4b).

11. A method for forming a tube (2) for producing a sealed package (3) from a packaging material sheet (4), the packaging material sheet (4) having a pre-applied opening device (5), the method comprising the steps of: a) Proceed the packaging material sheet (4) forward through the guide channel (50); b) Provide a plurality of folding rollers (11, 13) that define the channel (50) and have corresponding sidewalls (11a), wherein the folding rollers (11, 13) include at least one folding roller (13) having at least one recess on its sidewall (11a), the recess defining a groove (14); c) The sidewall (11a) contacts and cooperates with the packaging material sheet (4) to gradually fold the sheet (4) into a tubular shape; and d) Engage the groove (14) of the at least one folding roller (13) with the opening device (5); The at least one folding roller (13) has a plurality of grooves (14) on its sidewall (11a), and the method further includes the following steps: e) Engage the opening device (5) into the groove (14).

12. The method of claim 11, further comprising the step of: f) Drive the at least one folding roller (13) to rotate by performing the forward step a) and the engagement step e).

13. The method according to claim 11 or 12, further comprising the step of: g) Drive the at least one folding roller (13) to rotate about its rotation axis (B) by means of an actuation device.

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