Alignment module with automatic pressure control

Abstract

The present invention relates to an alignment module (11) for the lateral alignment of a blank (2). The alignment module is configured to receive the blank between an upper pressing member (22) and a lower alignment conveyor (25) and to convey the blank obliquely with respect to a guide (26). The upper pressing member (22) comprises a plurality of pressing rollers (42). At least some of the pressing rollers are connected to respective actuators (54). The actuators are configured to displace the pressing rollers (42) in the vertical direction, and the alignment module further comprises a control unit (32) and a memory (34), the control unit being configured to determine the required displacement for each pressing roller and to activate the respective actuators to effect the required displacement.

Description

Technical Field

[0001] The present invention relates to a converting machine for manufacturing paper and cardboard containers such as folding boxes. Specifically, the present invention relates to an alignment module configured to align a blank horizontally before folding.

Background Art

[0002] Converting machines such as folder-gluers are used in the manufacture of packaging articles such as paperboard boxes and cardboard boxes. These machines are configured to receive cut-to-shaped blanks and fold and glue them to form folding boxes or other similar packaging containers. The blanks include cutting lines that define the overall shape of the blank and crease lines that define the folding positions.

[0003] To ensure that folding occurs at the positions defined by the crease lines, the folder-gluer includes an alignment module located upstream of the folding module. The alignment module is configured to align the blank horizontally. An example of an alignment module is described in U.S. Patent No. 7,398,872.

[0004] Depending on the material and thickness of the blank, it is necessary to adjust the contact pressure between the upper pressing member and the alignment conveyor within the alignment module. This is generally done by manually adjusting the vertical position of the pressing roller of the upper pressing member by a machine operator.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In view of the prior art, an 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 accurately guided while reducing the risk of damaging the blank.

Means for Solving the Problem

[0007] This object is solved by the alignment module according to claim 1.

[0008] According to a first aspect of the present invention, an alignment module for lateral alignment of a blank in a converter is provided, the alignment module comprising an upper pressing member having a plurality of pressing rollers, and a lower alignment conveyor including an electric alignment conveyor belt and a guide, the alignment module receiving the blank between the upper pressing member and the lower alignment conveyor and being configured to carry the blank relative to the guide, the upper pressing rollers being connected to a linear frame member, at least a part of the pressing rollers being connected to respective actuators, the actuators being configured to displace the pressing rollers in a vertical direction, the alignment module further comprising a control unit and a memory, the control unit being configured to determine the required displacement for each pressing roller and to operate the respective actuators to effect the required displacement.

[0009] The present invention is based on the recognition that the automatic calculation and calibration of the vertical position of the pressing rollers relative to the blank enables individual accurate pressure settings. This further enables adaptation to different formats, materials, and blank thicknesses.

[0010] The upper pressing member and the lower alignment conveyor are preferably configured to carry the blank obliquely relative to the guide.

[0011] The contact pressure can be measured as a force over the entire area, i.e., in Pascal units. In one embodiment, the contact pressure applied on the blank can be between 0.5 and 3 bar.

[0012] The lateral alignment is performed in a direction perpendicular to the transport direction. The transport direction preferably extends from the feeder module to the alignment module and further downstream to the folding module. The transport direction extends from the feeder module to the delivery module of the converter. Thus, the transport direction extends from the inlet to the outlet of the converter.

[0013] In one embodiment, all the pressing rollers are connected to respective actuators, and all the pressing rollers are configured to be vertically displaced by respective actuators.

[0014] The control unit can calculate the required contact pressure for each pressing roller and configure each actuator to be displaced automatically to perform the required displacement of each pressing roller.

[0015] In one embodiment, the control unit is configured to divide the pressing rollers into a first group and a second group, and the pressing rollers in each group are given the same displacement, and the displacements are different between the first group and the second group.

[0016] In one embodiment, the pressing rollers of the first group are spaced apart from the blank, and the pressing rollers of the second group apply pressure to the blank.

[0017] In one embodiment, the inlet section is provided upstream of the alignment module, the pressing rollers in the inlet section are spaced apart from the blank so as not to contact the blank, and the rest of the pressing rollers contact the blank. Thus, the pressing rollers in the guide section located downstream of the inlet section contact the blank.

[0018] The control unit can further be configured to adjust the length of the inlet section by determining the longitudinal length in the conveying direction of the blank, and to move the pressing roller of the inlet section away from the blank.

[0019] In one embodiment, a connection structure is disposed between the pressing roller and the linear frame member. The connection structure includes a plurality of cantilever extensions and pivot levers, and each pivot lever interconnects the pressing roller to the cantilever extension.

[0020] In one embodiment, the connection structure further includes a vertical extension to the cantilever extension. The pivot lever has a first end connected to the vertical extension and a second end connected to the pressing roller, and the actuator includes a displacement rod connected to the pivot lever at a pivot point located on the pivot lever.

[0021] In one embodiment, the cantilever extension extends in a direction perpendicular to the linear frame member.

[0022] In one embodiment, the actuator is a pneumatic actuator and is connected to a pneumatic circuit.

[0023] In one embodiment, each actuator is connected to a separate pneumatic circuit, and a central valve is configured to distribute supply air to each pneumatic circuit.

[0024] In one embodiment, the control unit is configured to calculate the required displacement for the pressing roller from the thickness (b1) of the blank. The control unit can further calculate the required displacement for the pressing roller from the longitudinal length of the blank.

[0025] In one embodiment, the alignment module further includes a second alignment device, and the control unit is configured to deactivate one of the first and second alignment devices by moving all the pressing rollers of the deactivated alignment device to a disengaged position where they do not contact the blank.

[0026] In one embodiment, the inlet section is provided upstream of the alignment module, and the pressing roller of the inlet section can be spaced apart from the blank.

[0027] In one embodiment, the control unit is further configured to adjust the length of the inlet section by determining the longitudinal length of the blank in the conveying direction and move the plurality of rollers so that they are located at a predetermined vertical distance above the blank.

[0028] In this way, the pressing roller does not contact the blank. As a result, the box can exit the feeder before entering the alignment module with the alignment bar.

[0029] In one embodiment, the vertical position of the pressing roller can be adjusted from the control interface. Thereby, the operator can also perform recalibration of the contact pressure. The second calibration can be based on visual inspection and a test run.

[0030] In one embodiment, the memory is configured to store the length of the inlet section and the required displacement of the pressing roller and make them readable from the user interface. These set values can be stored together with an identifier, and the control unit can be configured to automatically displace the pressing roller when receiving the identifier. The identifier can be a job code related to the preset geometric characteristics of the blank. The geometric characteristics of the blank are preferably characterized by the longitudinal length and the thickness.

[0031] Hereinafter, the present invention will be described with reference to the accompanying drawings in which like reference numerals are assigned to like features.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2a

Figure 2b

Figure 3

Figure 4

Figure 5

Figure 6a

Figure 6B

Figure 7

Figure 8a

Figure 8b

Embodiments for Carrying Out the Invention

[0033] Specifically, refer to FIG. 1 showing the converter 1 in the form of the folding-gluing machine 1, and FIGS. 2a and 2b showing the blank 2 and the folding box 2' processed by the converter 1. The folding-gluing machine 1 is configured to receive a cutting part, form the blank 2 as shown in FIG. 2b, and then fold and glue the blank 2 to form the folding box 2' or other folded and glued packaging containers 2'. To enable folding, the blank 2 includes a longitudinal fold line 4 extending in the conveying direction T of the blank 2.

[0034] The blank 2 has a longitudinal length Lb in the conveying direction T. In the case of the blank 2 having irregular front edge 3a and rear edge 3b, the longitudinal length Lb is the maximum length of the blank 2 in the conveying direction T.

[0035] The folding-gluing machine 1 of the present invention comprises a series of different workstations in the form of modules. The modules can include a feeder module 10, an alignment module 11, a folding pre-breaking module 12, a gluing module 14, and a folding module 16 from the inlet A to the outlet B of the converter 1 and in the conveying direction T. The folding-gluing machine 1 can further comprise a main user interface 13 and a quality control system 18.

[0036] After the gluing module and the folding module, a delivery module and an adjustment section 21 can be provided to count the roof plate-like flow of the folding box 2' and separate it into separate batches.

[0037] The converter 1 further comprises a conveying system 19 comprising a conveyor such as an endless belt and rollers configured to convey the blank 2 in the conveying direction T. The converter 1 also comprises a central control circuit 20 configured to control the operation of the converter 1.

[0038] The alignment module 11 is arranged downstream of the feeder unit 10 in the conveying direction T and is configured to laterally align the blank 2 to a predetermined lateral position. The predetermined lateral position is defined by the position of the longitudinal fold line 4 and the position of the folding tool in the converter 1.

[0039] The alignment module 11 can comprise a mechanical structure similar to the alignment module disclosed in U.S. Patent No. 7,398,872 and shown in FIG. 3. This mechanical structure comprises an upper pressing member 22 provided with a plurality of pressing rollers 42 arranged in a row, 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.

[0040] The alignment module 11 is configured to receive the blank 2 between the upper pressing member 22 and the alignment conveyor 24. The upper pressing member 22 and the alignment conveyor 24 are arranged at a predetermined angle in the conveying direction T so as to guide the side edges L, R of the blank 2 in contact with the guide 26. The guide 26 is arranged such that the longitudinal extension L coincides with the conveying direction T. Therefore, the conveying direction T is defined by the guide 26 within the alignment module 11.

[0041] The alignment conveyor 24 is composed of an endless conveyor belt 23 having a contact length Lc configured to contact the blank 2 and send it forward in the conveying direction T.

[0042] As shown in FIGS. 4 and 5, according to the present invention, at least a part of the pressing roller 42 is connected to each actuator 54. Therefore, the dedicated actuator 54 is connected to at least a part of the pressing roller 42. The actuator 54 is configured to bring about a vertical displacement of the pressing roller 42 and is capable of setting the contact pressure on the blank 2. In a preferred embodiment, each of the pressing rollers 42 of the alignment module 11 is displaceable by each actuator 54.

[0043] However, it is also possible to make only a part of the pressing rollers displaceable by the actuator 54. In this embodiment, some of the pressing rollers 42 can be manually movable or fixedly positioned.

[0044] The alignment module 11 can further include an entrance section I. The entrance section I provides a distance Li over which the blank 2 is not guided. This can be achieved by setting the contact pressure of the pressing roller 42 of the entrance section I to zero or at least lower than the guiding section G of the pressing member 22, such that the pressing member 22 does not change the trajectory of the blank 2 in the entrance section I. Thereby, the alignment module 11 can receive the entire longitudinal length Lb of the blank 2 before laterally biasing the blank 2. Also, thereby, the blank 2 can exit the feeder module 10 before its trajectory is changed. Optionally, some of the pressing rollers 42 of the entrance section can be either fixed or manually movable.

[0045] The length of the entrance section can be configured such that the blank 2 will only be laterally moved when the entire longitudinal length Lb of the blank 2 is within the alignment module 11. Thus, the length Li of the entrance section can be selected to correspond to the longitudinal length Lb of the blank 2.

[0046] The alignment module 11 further includes a control circuit 30 including a control unit 32 and a memory 34. The control circuit 30 can be connected to the central control circuit 20 and the user interface 13.

[0047] As shown in FIG. 7, the converter 1 preferably includes 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, and the second alignment device 25b is configured to abut against the right side R of the blank 2. However, the first and second alignment devices 25a, 25b are not used simultaneously. Instead, the first and second alignment devices 25a, 25b provide the option to select which side edge R, L of the blank 2 to align with the guide 26. Generally, a straight or uniform side edge is more conveniently aligned with the guide 26 than an irregular side edge.

[0048] When one alignment device is operating, the other device is inoperative. In the inoperative alignment device, the pressing roller 42 can be moved upward and away from the blank 2, and the pressing roller 42 of the inoperative alignment device is configured not to contact the blank 2. Alternatively, the contact pressure of the pressing roller 42 is set such that the pressing roller 42 contacts the blank 2 but does not apply sufficient force to change the trajectory of the blank 2. Also, the lower alignment conveyor 24 of the inoperative alignment device can be moved to a position straight in the conveying direction T. The guides 26 are arranged on the operating alignment devices 25a, 25b.

[0049] The pressing roller 42 can rotate freely. As can be best seen from FIGS. 6a, 8a and 8b, the pressing roller 42 preferably has an elastic contact surface 44. For example, the contact surface 44 can include rubber.

[0050] The pressing roller 42 is attached to a linear frame member 46. A connecting structure 48 is disposed between the pressing roller 42 and the linear frame member 46. The connecting structure includes a plurality of cantilever extensions 50, a vertical extension 51 (see FIG. 8b), a pivotable lever 52, and an actuator 54.

[0051] The plurality of cantilever extensions 50 are attached to the linear frame member 46. The cantilever extensions 50 extend in a direction P perpendicular to the longitudinal extension L of the linear frame member 46. Thus, the cantilever extensions 50 extend parallel to each other, preferably in a horizontal direction.

[0052] As can be best seen from FIG. 8a, each pivotable lever 52 has a first distal end e1 to which the pressing roller 42 is rotatably attached. The second distal end e2 of the pivotable lever 52 is connected to the vertical extension 51 at a central pivot point 53.

[0053] As shown in FIG. 8b, the actuator 54 includes a displacement rod 55 having a tip 57 connected to the pivotable lever 52. The pressing roller 42 can be elastically attached to the displacement rod 55. The spring member 58 is configured to displace the pressing roller 42 away from the conveyor belt 23. Therefore, the spring member 58 is displaced so as to cancel the pressure applied by the actuator 54. The spring member 58 can be a compression spring 58 disposed around the displacement rod 55 of the actuator 54.

[0054] The displacement rod 55 of the actuator 54 is reciprocally movable, and the contact pressure of the pressing roller 42 can be adjusted by changing the fluid pressure supplied to the actuator 54.

[0055] The actuator rod 55 is preferably arranged such that the longitudinal extension coincides with the vertical direction V. The tip (i.e., the free end) of the displacement rod 55 is connected to the pivotable lever 52 at the pivot point 59.

[0056] When the actuator rod 55 extends, the pressing roller 42 describes a circular orbit with respect to the central pivot point 53. The length L1 of the pivotable lever 52 from the central pivot point 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 as the length from the central pivot point 53 to the rotation axis 49 of the pressing roller 42.

[0057] Each of the actuators 54 is connected to a separate fluid circuit 60 (see FIG. 7). The fluid pressure in each fluid circuit 60 can be changed so that the displacement rod 55 moves and the contact pressure of each pressing roller 42 onto the blank is adjusted. Thereby, the contact pressure of the pressing roller 42 can be changed 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. The central valve 61 can be fluidly connected to each fluid circuit 60 and configured to distribute the supply air to each actuator 54.

[0058] Preferably, the fluid pressure in each fluid circuit 60 can be individually changed so as to make the pressing roller 42 either in an operating state or a non-operating state. The operating state means that the pressing roller 42 is applying pressure to the blank 2. The non-operating state means that the pressing roller 42 is not applying pressure to the blank 2, and preferably, there is no contact between the non-operating pressing roller 42 and the blank 2. Preferably, the fluid pressure in the inlet section is the same for all the pressing rollers 42 located in the inlet section. Therefore, the pressure applied by the pressing roller 42 in the inlet section can be set to zero. The fluid pressure of the pressing roller 42 in the operating state may be the same for all the pressing rollers 42 located in the guide section G.

[0059] The actuator 54 can be automatically operated based on a command from the control device 32. The command can be manually input to the user interface 13. However, it is convenient that the command is presented by the calculated set values provided by the control unit 32. Such calculations may be based on a plurality of calibration parameters.

[0060] The converter 1 is calibrated each time the dimensions of the blank change. The calibration parameters include the thickness b1 of the blank. Preferably, the calibration parameters also include the longitudinal length Lb of the blank. Also, material properties such as elastic deformation characteristics related to the material density can be selected as calibration parameters.

[0061] In some cases, the type of blank 2 to be processed occurs repeatedly as appropriate, and the set of stored setting parameters can be selected from the operator interface 13 and read from the memory 34. The control unit 32 can detect the same job code or identifier and automatically displace the actuator 54.

[0062] These calibration parameters are input into the central control circuit 20 of the converter 1. The calibration parameters can be included in a data set in a processing file. Such a data set can be input physically remotely or manually into the central control circuit 20 of the converter 1. Physical input includes inputting some hardware such as a data cable or a flash drive into the communication port of the converter 1. Remote input can be executed from a location of remote computing connected to the central control circuit 20 in a network architecture such as a cloud network.

[0063] The alignment side is selected based on the geometry of the side edges L, R of the blank 2. This can be selected manually by the operator. Alternatively, the control unit 32 can execute a calculation to determine which side is most suitable for alignment.

[0064] The control unit 32 is configured to selectively activate the first alignment device 25a or the second alignment device 25b by moving the pressing roller 42 of the invalid alignment device to a predetermined distance from the blank 2. In this way, the pressing roller 42 of the invalid upper pressing member 22 does not contact the blank 2. Alternatively, the pressing roller 42 is in contact with the blank 2, but the pressure applied by the pressing roller 42 is set to allow lateral movement of the blank 2.

[0065] The memory 34 includes a program having an algorithm that enables the control unit 32 to calculate the required contact pressure from each pressing roller 42. The algorithm is adapted to perform the calculation using calibration parameters.

[0066] Based on the longitudinal length Lb of the blank 2, the control unit 32 can further determine the longitudinal length Li of the inlet section and determine which pressing roller 42 needs to be deactivated and moved away from the blank 2.

Claims

1. An alignment module (11) for lateral alignment of a blank (2) within a converter (1), said alignment module comprising an upper pressing member (22) with a plurality of pressing rollers (42), and a lower alignment conveyor (24) including an electric alignment conveyor belt (23) and a guide (26), and comprising a first alignment device (25a), said alignment module being configured to receive the blank between the upper pressing member and the lower alignment conveyor and to carry the blank relative to the guide, said upper pressing rollers being connected to a linear frame member (46), at least some of said pressing rollers being connected to respective actuators (54), said actuators being configured to displace said pressing rollers (42) in a vertical direction (V), said alignment module further comprising a control unit (32) and a memory (34), said control unit being configured to determine a required displacement for each of said pressing rollers and to actuate each of said actuators to effect said required displacement. Alignment module.

2. All of said pressing rollers (42) are connected to respective ones of said actuators (54), and all of said pressing rollers (42) are configured to be vertically displaced by respective ones of said actuators. The alignment module according to claim 1.

3. Said control unit is configured to calculate a required contact pressure for each of said pressing rollers and to displace each of said actuators to automatically effect said required displacement for each of said pressing rollers. The alignment module according to claim 1 or 2.

4. Said control unit is configured to divide said pressing rollers into a first group and a second group, said pressing rollers of each group being given the same displacement, said displacement being different for said first and said second groups. The alignment module according to any one of claims 1 to 3.

5. Said pressing rollers of said first group are spaced apart from the blank, and said pressing rollers of said second group apply pressure to the blank. The alignment module according to claim 4.

6. The inlet section (I) is provided upstream of the alignment module, and the pressing roller of the inlet section is spaced apart from the blank so as not to contact the blank, and the rest of the pressing roller contacts the blank. The alignment module according to claim 5.

7. The control unit is further configured to adjust the length of the inlet section by determining the longitudinal length (Lb) of the blank in the transport direction and to move the pressing roller of the inlet section away from the blank. The alignment module according to claim 6.

8. A connecting structure (48) is arranged between the pressing roller and the linear frame member. The connecting structure includes a plurality of cantilever extensions (50) and pivot levers (52), and each of the pivot levers interconnects the pressing roller to the cantilever extension. The alignment module according to any one of claims 1 to 7.

9. The connecting structure further includes a vertical extension (51) to the cantilever extension. The pivot lever has a first end (e1) connected to the vertical extension and a second end (e2) connected to the pressing roller. The actuator includes a displacement rod (55) connected to the pivot lever at a pivot point (59) located on the pivot lever. The alignment module according to claim 8.

10. The cantilever extension extends in a direction (P) perpendicular to the linear frame member. The alignment module according to claim 9.

11. The actuator is a pneumatic actuator and is connected to a pneumatic circuit (60). The alignment module according to any one of claims 1 to 10.

12. Each of the actuators is connected to a separate pneumatic circuit, and a central valve (61) is configured to distribute supply air to each of the pneumatic circuits. The alignment module according to claim 11.

13. The control unit is configured to calculate the required displacement regarding the pressing roller from the thickness (b1) of the blank. The alignment module according to any one of claims 1 to 12.

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

15. The alignment module according to any one of claims 1 to 14, further comprising a second alignment device (25b), wherein the control unit is configured to deactivate one of the first and second alignment devices (25a, 25b) by moving all of the pressing rollers of the deactivated alignment device to a disengaged position where they do not contact the blank.

16. The alignment module according to any one of claims 1 to 15, wherein the vertical position of the pressing roller can be adjusted from a control interface.

17. The alignment module according to any one of claims 1 to 16, wherein the memory stores the length and contact pressure of the inlet section and is configured to be readable therefrom by a user interface (13).

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