Alignment module with automatic pressure control

Abstract

The invention relates to an alignment module (11) for lateral alignment of blanks (2). The alignment module is configured to receive the blank between the upper pressing member (22) and the lower alignment transfer device (25) and to transfer the blank obliquely against the guide (26). The upper pressing member includes a plurality of pressing rollers (42), and includes an upper pressing member (22) provided with the plurality of pressing rollers (42). At least some of the compression rollers are connected to respective actuators (54). The actuators are configured to move the compression rollers (42) in a vertical direction, and wherein the alignment module further comprises a control unit (32) and a memory (34) wherein the control unit is configured to determine a required displacement for each compression roller and to actuate each respective actuator to perform the required displacement.

Description

Technical Field

[0001] The present invention relates to a converting machine for producing paper and paperboard containers, such as folding boxes. In particular, the present invention relates to an alignment module configured to laterally align blanks prior to folding. Background Art

[0002] Converting machines such as folder-gluers are used to produce packaging items such as paperboard and cartons. These machines are configured to receive cut-to-shape blanks and then fold and glue them together to form folding boxes or other similar packaging containers. The blanks are provided with cut lines, which define the overall shape of the blank, and crease lines, which define the locations of the folds.

[0003] In order to ensure that the folding is done at the position defined by the crease lines, the folder-gluer comprises an alignment module located upstream of the folding module. The alignment module is configured to align the blank laterally. An example of an alignment module is described in document US7398872.

[0004] Depending on the material and thickness of the blank, the contact pressure between the upper pressing member and the alignment conveyor in the alignment module needs to be adjusted. This is usually done manually by the machine operator by adjusting the vertical position of the pressing rollers in the upper pressing member. Summary of the invention

[0005] In view of the prior art, the object of the present invention is to improve the accuracy of the contact pressure in the alignment module so that the blank is gripped and guided accurately while reducing the risk of damaging the blank.

[0006] This object is achieved by an alignment module according to claim 1 .

[0007] According to a first aspect of the present invention, an alignment module for laterally aligning blanks in a conversion machine is provided, the alignment module comprising a first alignment device, the first alignment device comprising an upper pressing member provided with a plurality of pressing rollers, a lower alignment conveyor comprising a motorized alignment conveyor belt and a guide, wherein the alignment module is configured to receive the blanks between the upper pressing member and the lower alignment conveyor and to convey the blanks against the guide, and wherein the upper pressing rollers are connected to a linear frame member, and wherein at least some of the pressing rollers are connected to corresponding actuators, the actuators being configured to move the pressing rollers in a vertical direction, and wherein the alignment module further comprises a control unit and a memory, wherein the control unit is configured to determine the required displacement of each pressing roller and to actuate each corresponding actuator to perform the required displacement.

[0008] The invention is based on the recognition that automatically calculating and calibrating the vertical position of the press roller relative to the blank allows an individual and precise pressure setting. This further allows adapting to different formats, materials and blank thicknesses.

[0009] The upper pressing member and the lower alignment conveyor are preferably configured to convey the blank obliquely against the guide.

[0010] The contact pressure may be measured as force over area, ie in Pascals. In one embodiment, the contact pressure applied to the blank may be between 0.5 and 3 bar.

[0011] The lateral alignment is in a direction perpendicular to the transport direction. The transport direction preferably extends from the feeder module to the alignment module and further to the folding module in a downstream direction. The transport direction extends from the feeder module of the conversion machine to the conveying module. Thus, the transport direction extends from the inlet to the outlet of the conversion machine.

[0012] In one embodiment, all of the pressing rollers are connected to corresponding actuators, and all of the pressing rollers are configured to be vertically moved by their respective actuators.

[0013] The control unit may be configured to calculate a required contact pressure for each pressure roller and to move the corresponding actuator to automatically perform the required displacement of each pressure roller.

[0014] In one embodiment, the control unit is configured to divide the pressing rollers into a first group and a second group, wherein the pressing rollers in each group are provided with the same displacement, and the displacements of the first group and the second group are different.

[0015] In one embodiment, the pressing rollers in the first set are kept at a distance from the blank, while the pressing rollers in the second set apply pressure to the blank.

[0016] In one embodiment, the inlet section is arranged in the upstream part of the alignment module, and wherein the pressing rollers in the inlet section are kept at a distance from the blank so that they do not contact the blank, while the remaining pressing rollers contact the blank. Thus, the pressing rollers in the guide section downstream of the inlet section contact the blank.

[0017] The control unit may also be configured to adjust the length of the entry section by determining the longitudinal length of the blank in the transport direction and to move the pressing rollers in the entry section such that they are spaced apart from the blank.

[0018] In one embodiment, a connection structure is arranged between the pressure roller and the linear frame member, the connection structure including a plurality of cantilever extensions and pivot levers, wherein each pivot lever interconnects the pressure roller with the cantilever extension.

[0019] In one embodiment, the connection structure also includes a vertical extension to the cantilever extension, and wherein the pivot lever has a first end connected to the vertical extension and a second end connected to the pressure roller, and wherein the actuator includes a shift rod that is connected to the pivot lever at a pivot point located on the pivot lever.

[0020] In one embodiment, the cantilever extension extends in a direction perpendicular to the linear frame member.

[0021] In one embodiment, the actuator is a pneumatic actuator and is connected to a pneumatic circuit.

[0022] In one embodiment, each actuator is connected to a separate pneumatic circuit, and wherein the central valve is configured to distribute the air supply to each pneumatic circuit.

[0023] In one embodiment, the control unit is configured to calculate the required displacement of the pressing roller according to the thickness (b1) of the blank. The control unit can also calculate the required displacement of the pressing roller according to the longitudinal length of the blank.

[0024] In one embodiment, the alignment module further comprises a second alignment device, and wherein the control unit is configured to deactivate one of the first and second alignment devices by moving all press rollers of the deactivated alignment device to a clear position out of contact with the blank.

[0025] In one embodiment, the inlet section is arranged in an upstream portion of the alignment module, and wherein the pressing rollers in the inlet section are kept at a distance from the blank.

[0026] In one embodiment, the control unit is further configured to adjust the length of the inlet portion by determining a longitudinal length of the blank in the transport direction and moving the plurality of rollers such that they are located at a vertical distance above the blank.

[0027] In this way, the pressing rollers do not contact the blanks. This allows the boxes to leave the feeder using the alignment bars before entering the alignment module.

[0028] In one embodiment, the vertical position of the pressure roller can be adjusted from the control interface. This also allows the operator to perform a second calibration of the contact pressure. The second calibration can be based on visual inspection and test runs.

[0029] In one embodiment, the memory is configured to store the inlet portion length and the required displacement of the pressure roller and make them retrievable from the user interface. These settings can be stored together with an identifier, and the control unit can be configured to automatically move the pressure roller when the control unit receives the identifier. The identifier can be a work code associated with a predefined geometric feature of the blank. The geometric feature of the blank is preferably characterized by its longitudinal length and thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will now be described with reference to the accompanying drawings, in which like features are indicated by the same reference numerals, and in which:

[0031] - Figure 1is a schematic diagram of a converting machine in a folder-gluer configuration;

[0032] - Figure 2a and Figure 2b They are top views of the blank and the folding box respectively;

[0033] - Figure 3 is a schematic perspective view of an alignment module known in the prior art;

[0034] - Figure 4 is a schematic cross-sectional side view of an alignment device according to one embodiment of the present invention as seen from a first side;

[0035] - Figure 5 Seen from the second side Figure 4 A schematic cross-sectional side view of an alignment device;

[0036] - Figure 6a Seen from the first side Figure 4 A schematic perspective view of an alignment device;

[0037] - Figure 6b Seen from the second side Figure 4 A schematic perspective view of an alignment module;

[0038] - Figure 7 is a schematic perspective view of a left-alignment device and a right-alignment device; and

[0039] - Figure 8 is a detailed view of an upper pressing member in an alignment device according to one embodiment of the invention. DETAILED DESCRIPTION

[0040] See the accompanying drawings, especially Figure 1 and Figure 2a and Figure 2b , Figure 1 A converting machine 1 in the form of a folder-gluer 1 is shown, Figure 2a and Figure 2b The blank 2 and the folding box 2' to be processed in the converting machine 1 are shown. The folder-gluer 1 is configured to receive a blank 2 and a folding box 2' to be processed in the converting machine 1. Figure 2b The cut-to-shape blank 2 is shown, which is then folded and glued to form a folding box 2' or another folded and glued packaging container 2'. To enable folding, the blank 2 is provided with longitudinal fold lines 4 extending in the transport direction T of the blank 2.

[0041] The blank 2 has a longitudinal length Lb along the transport direction T. The longitudinal length Lb is the maximum length of the blank 2 along the transport direction T for a blank 2 having an irregular leading edge 3 a and a trailing edge 3 b .

[0042] The present folder-gluer 1 comprises a series of different workstations in the form of modules. From the inlet A to the outlet B of the converter 1, along the transport direction T, the modules may comprise: a feeder module 10, an alignment module 11, a folding pre-breaking module 12, a gluing module 14 and a folding module 16. The folder-gluer 1 may also comprise a main user interface 13 and a quality control system 18.

[0043] After the gluing and folding modules, a conveying module and a conditioning section 21 may be provided in order to count the imbricate flow of folded boxes 2 ′ and to divide it into individual batches.

[0044] The conversion machine 1 further comprises a conveying system 19 comprising conveying means, such as endless belts and rollers, configured to transport the blanks 2 along a transport direction T. The conversion machine 1 further comprises a central control circuit 20 configured to control the operation of the conversion machine 1 .

[0045] The alignment module 11 is arranged downstream of the feeder unit 10 in the transport direction T and is configured to laterally align the blank 2 to its predetermined lateral position. The predetermined lateral position is defined by the position of the longitudinal crease lines 4 and the position of the folding tools in the conversion machine 1 .

[0046] The alignment module 11 may be provided with an alignment module similar to that disclosed in US7398872 and as Figure 3 The mechanical structure shown in FIG. 1 includes an upper pressing member 22 provided with a plurality of pressing rollers 42 arranged in a straight line, a lower alignment conveyor 24 and a guide 26 . The upper pressing member 22 and the lower alignment conveyor 24 form an alignment device 25 .

[0047] The alignment module 11 is configured to receive the blank 2 between an upper pressing member 22 and an alignment conveyor 24. The upper pressing member 22 and the alignment conveyor 24 are arranged at an angle in the transport direction T so that the lateral edges L, R of the blank 2 abut against the guides 26. The guides 26 are arranged so that their longitudinal extension L coincides with the transport direction T. Therefore, the transport direction T is defined by the guides 26 in the alignment module 11.

[0048] The alignment conveyor 24 comprises an endless conveyor belt 23 having a contact length Lc, which is configured to contact the blank 2 and drive the blank 2 forward in the transport direction T.

[0049] like Figure 4 and Figure 5As shown, according to the present invention, at least some of the press rollers 42 are connected to corresponding actuators 54. Therefore, dedicated actuators 54 are connected to at least some of the press rollers 42. The actuators 54 are configured to provide vertical displacement to the press rollers 42 so that their contact pressure on the blank 2 can be set. In a preferred embodiment, each press roller 42 in the alignment module 11 can be moved by a corresponding actuator 54.

[0050] However, it is also possible to arrange only some of the pressure rollers so as to be movable by the actuator 54. In this embodiment, some of the pressure rollers 42 can be moved manually or fixedly positioned.

[0051] The alignment module 11 may also include an inlet portion I. The inlet portion I provides a distance Li over which the blank 2 is not guided. This can be achieved by setting the contact pressure of the press rollers 42 in the inlet portion I to zero or at least lower than the contact pressure in the guide portion G of the pressing member 22, so that the pressing member 22 does not change the trajectory of the blank 2 in the inlet portion I. This allows the alignment module 11 to receive the entire longitudinal length Lb of the blank 2 before pushing the blank 2 to the side. This also allows the blank 2 to exit from the feeder module 10 before modifying its trajectory. Optionally, some of the press rollers 42 in the inlet portion I can be configured to be fixed or manually movable.

[0052] The length of the inlet portion I can be configured so that the blank 2 will only move laterally when the entire longitudinal length Lb of the blank 2 is located in the alignment module 11. Therefore, the length Li of the inlet portion can be selected to correspond to the longitudinal length Lb of the blank 2.

[0053] The alignment module 11 further comprises a control circuit 30, which comprises a control unit 32 and a memory 34. The control circuit 30 may be connected to the central control circuit 20 and the user interface 13.

[0054] like Figure 7 As shown, the conversion machine 1 preferably comprises a first alignment device 25a and a second alignment device 25b. The first alignment device 25a is configured to abut against the left side L of the blank 2, while the second alignment device 25b is configured to abut against the right side R of the blank 2. However, the first alignment device 25a and the second alignment device 25b are not used at the same time. Instead, they provide the option of selecting which lateral edge R, L of the blank 2 is aligned against the guide 26. Generally, straight or uniform lateral edges are more conducive to alignment against the guide 26 than irregular lateral edges.

[0055] When one alignment device is activated, the other alignment device is deactivated. In the deactivated alignment device, the pressure roller 42 can be moved upward and away from the blank 2, so that the pressure roller 42 of the deactivated alignment device does not contact the blank 2. Alternatively, the contact pressure of the pressure roller 42 is set so that the pressure roller 42 contacts the blank but does not apply a force sufficient to change the trajectory of the blank 2. The lower alignment conveyor 24 in the deactivated alignment device can also be moved to a position straight in the transport direction T. The guide 26 is positioned in the activated alignment devices 25a, 25b.

[0056] The pressure roller 42 can be idle. Figure 6a , 8a As best shown in Figure 8b, the pressure roller 42 is preferably provided with a resilient contact surface 44. For example, the contact surface 44 may comprise rubber.

[0057] The pressure roller 42 is attached to the linear frame member 46. A connecting structure 48 is arranged between the pressure roller 42 and the linear frame member 46. The connecting structure includes a plurality of cantilever extensions 50, vertical extensions 51 (see Figure 8b ), pivotable lever 52 and actuator 54.

[0058] A plurality of cantilever extensions 50 are attached to the linear frame members 46. The cantilever extensions 50 extend in a direction P perpendicular to the longitudinal extension L of the linear frame members 46. Thus, the cantilever extensions 50 extend parallel to each other and preferably in a horizontal direction.

[0059] like Figure 8a As best shown in FIG. 5 , each pivotable lever 52 comprises a first distal end e1 on which the pressure roller 42 is rotatably mounted. A second distal end e2 of the pivotable lever 52 is connected to the vertical extension 51 at a central pivot point 53 .

[0060] like Figure 8b As shown, the actuator 54 is provided with a shift rod 55 having an end 57 connected to the pivotable lever 52. The pressure roller 42 can be elastically attached to the shift rod 55. The spring member 58 is configured to bias the pressure roller 42 away from the conveyor belt 23. Therefore, the spring member 58 is biased to counteract the pressure applied by the actuator 54. The spring member 58 can be a compression spring 58 arranged around the shift rod 55 of the actuator 54.

[0061] The shift rod 55 of the actuator 54 can move in a reciprocating manner, so that the contact pressure of the pressure roller 42 can be adjusted by changing the fluid pressure supplied to the actuator 54.

[0062] The actuator rod 55 is preferably arranged with its longitudinal extension coinciding with the vertical direction V. The distal end, ie the free end, of the displacement rod 55 is connected to the pivotable lever 52 at a pivot point 59 .

[0063] When the actuator rod 55 is extended, the pressure roller 42 performs a circular trajectory relative to the central pivot point 53. The length L1 of the pivotable lever 52 from 53 to the axis of the roller is selected to provide a vertical displacement component greater than the horizontal displacement. The length L1 can be measured from 53 to the rotation axis 49 of the pressure roller 42.

[0064] Each actuator 54 is connected to a separate fluid circuit 60 (see Figure 7 ). The fluid pressure in each fluid circuit 60 can be modified so that the shift rod 55 moves and adjusts the contact pressure of each pressing roller 42 on the blank. This allows the contact pressure of the pressing roller 42 to be modified according to the thickness and compressibility of the blank 2. The fluid circuit 60 is preferably operable individually for each pressing roller 42. The fluid circuit 60 is preferably a pneumatic circuit. However, a hydraulic circuit 60 is also possible. A central valve 61 can be fluidically connected to each fluid circuit 60 and configured to distribute the air supply to each actuator 54.

[0065] Preferably, the fluid pressure in each fluid circuit 60 can be modified individually so that the pressure roller 42 is activated or deactivated. Activation means that the pressure roller 42 is applying pressure to the blank 2. Deactivation means that the pressure roller 42 is not applying pressure to the blank 2, and there is no contact between the preferably deactivated pressure roller 42 and the blank 2. Preferably, the fluid pressure in the inlet portion I is the same for all the pressure rollers 42 located in the inlet portion I. Therefore, the pressure applied by the pressure roller 42 in the inlet portion I can be zero. The fluid pressure in the activated pressure roller 42 can be the same for all the pressure rollers 42 located in the guide portion G.

[0066] The actuator 54 may be operated automatically according to instructions from the control unit 32. The instructions may be manually input into the user interface 13. However, advantageously, the instructions are provided by a calculation arrangement provided by the control unit 32. Such calculation may be based on a number of calibration parameters.

[0067] Each time the blank size changes, the conversion machine 1 is calibrated. The calibration parameters include the blank thickness b1. Preferably, the calibration parameters also include the longitudinal length Lb of the blank. Material properties, such as elastic deformation properties related to the material density, can also be selected as calibration parameters.

[0068] Sometimes the type of blank 2 to be processed will repeat from time to time and a set of stored configuration parameters may be selected from the operator interface 13 and retrieved from the memory 34. The control unit 32 may detect the same job code or identifier and move the actuator 54 automatically.

[0069] These calibration parameters are input into the central control circuit 20 of the conversion machine 1. The calibration parameters may be included in a data set that is included in the processing file. Such a data set may be input into the central control circuit 20 of the conversion machine 1 physically, remotely, or manually. Physical input includes inputting hardware such as a data cable or flash drive into a communication port of the conversion machine 1. Remote input may be performed from a remote computing location connected to the central control circuit 20 in a network architecture (e.g., a cloud network).

[0070] The alignment side is selected based on the geometry of the lateral edges L, R of the blank 2. This may be selected manually by an operator. Alternatively, the control unit 32 may perform a calculation to determine which lateral side is best suited for alignment.

[0071] The control unit 32 is configured to selectively activate the first alignment device 25a or the second alignment device 25b by moving the pressure roller 42 of the disabled alignment device to a certain distance from the blank 2. In this way, the pressure roller 42 of the disabled upper pressing member 22 does not come into contact with the blank 2. Alternatively, the pressure roller 42 comes into contact with the blank 2, but the pressure applied by the pressure roller 42 is set to allow the blank 2 to move laterally.

[0072] The memory 34 comprises a program with an algorithm which allows the control unit 32 to calculate the required contact pressure from each pressure roller 42. The algorithm uses calibration parameters to perform the calculations.

[0073] Based on the longitudinal length Lb of the blank 2 , the control unit 32 may further determine the longitudinal length Li of the inlet portion I and determine which press rollers 42 should be deactivated and moved away from the blank 2 .

Claims

1. An alignment module (11) for lateral alignment of blanks (2) in a conversion machine (1), the alignment module comprising a first alignment device (25a), the first alignment device comprising an upper pressing member (22) provided with a plurality of pressing rollers (42), a lower alignment conveyor (24) comprising an electric alignment conveyor belt (23) and a guide (26), wherein the alignment module is configured to receive the blank between the upper pressing member and the lower alignment conveyor and to convey the blank against the guide, and wherein the upper pressing rollers are connected to a linear frame member (46), and wherein at least some of the pressing rollers are connected to corresponding actuators (54), the actuators being configured to move the pressing rollers (42) in a vertical direction (V), and wherein the alignment module further comprises a control unit (32) and a memory (34), wherein the control unit is configured to determine a required displacement of each pressing roller and to actuate each corresponding actuator to perform the required displacement.

2. The alignment module according to claim 1, wherein all the pressure rollers (42) are connected to a corresponding actuator (54) and are configured to be moved vertically by the corresponding actuator.

3. An alignment module according to claim 1 or 2, wherein the control unit is configured to calculate the required contact pressure of each pressure roller and to move the corresponding actuator to automatically perform the required displacement of each pressure roller.

4. The alignment module according to any of the preceding claims, wherein the control unit is configured to divide the pressure rollers into a first group and a second group, wherein the pressure rollers in each group are provided with the same displacement, and the displacements of the first group and the second group are different.

5. Alignment module according to the preceding claim, wherein the pressing rollers of the first set are kept at a distance from the blank, whereas the pressing rollers of the second set apply pressure to the blank.

6. An alignment module according to claim 5, wherein an inlet part (I) is provided in the upstream part of the alignment module, and wherein the pressing rollers in the inlet part keep a distance from the blank so that they do not contact the blank, while the remaining pressing rollers contact the blank.

7. An alignment module according to the preceding claim, wherein the control unit is further configured to adjust the length of the entry section by determining the longitudinal length (Lb) of the blank in the transport direction, and to move the pressing rollers in the entry section so that they keep a distance from the blank.

8. An alignment module according to any one of the preceding claims, wherein a connecting structure (48) is arranged between the pressure roller and the linear frame member, the connecting structure comprising a plurality of cantilever extensions (50) and pivot levers (52), wherein each pivot lever interconnects the pressure roller with the cantilever extension.

9. An alignment module according to claim 8, wherein the connecting structure also includes a vertical extension (51) to the cantilever extension, and wherein the pivot lever has a first end (e1) connected to the vertical extension and a second end (e2) connected to the pressure roller, and wherein the actuator includes a shift rod (55) connected to the pivot lever at a pivot point (59) located on the pivot lever.

10. The alignment module of claim 9, wherein the cantilever extension extends in a direction (P) perpendicular to the linear frame members.

11. Alignment module according to any of the preceding claims, wherein the actuator is a pneumatic actuator and is connected to a pneumatic circuit (60).

12. Alignment module according to the preceding claim, wherein each actuator is connected to a separate pneumatic circuit, and wherein the central valve (61) is configured to distribute the air supply to each pneumatic circuit.

13. Alignment module according to any of the preceding claims, wherein the control unit is configured to calculate the required displacement of the pressing rollers as a function of the thickness (b1 ) of the blank.

14. The alignment module according to claim 13, wherein the control unit is configured to further calculate the required displacement of the pressing roller according to the longitudinal length (Lb) of the blank.

15. An alignment module according to any one of the preceding claims, further comprising a second alignment device (25b), and wherein the control unit is configured to deactivate one of the first and second alignment devices (25a, 25b) by moving all pressure rollers of the deactivated alignment device to a clearing position in which they are not in contact with the blank.

16. An alignment module according to any one of the preceding claims, wherein the vertical position of the pressure roller is adjustable from a control interface.

17. Alignment module according to any of the preceding claims, wherein the memory is configured to store the entry portion length and the contact pressure and make them retrievable from a user interface (13).

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