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 containers of paper and cardboard, 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 positions of the folds.

[0003] To ensure that the folding is performed 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, 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. [Means for solving the problem]

[0007] This objective is solved by the alignment module described in 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 a first alignment device comprising an upper pressing member having a plurality of pressing rollers and a lower alignment conveyor including an electrically operated alignment conveyor belt and guides, the alignment module is configured to receive the blank between the upper pressing member and the lower alignment conveyor and to carry the blank toward the guides, the upper pressing rollers are connected to a linear frame member, at least a portion of the pressing rollers are connected to their respective actuators, the actuators are configured to displace the pressing rollers in the vertical direction, the alignment module further comprises a control unit and a memory, the control unit is configured to determine the required displacement for each pressing roller and to actuate the respective actuators to perform the required displacement.

[0009] This invention is based on the recognition that automatic calculation and calibration of the vertical position of the pressure roller relative to the blank enables individual and precise pressure settings. This further allows for adaptation to different formats, materials, and blank thicknesses.

[0010] The upper pressing member and the lower alignment conveyor are preferably configured to transport the blank at an angle to the guide.

[0011] Contact pressure can be measured as a force across the entire area, i.e., in Pascals. In one embodiment, the contact pressure applied to the blank can be between 0.5 and 3 bar.

[0012] Lateral alignment is performed 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 converter's output module. Therefore, the transport direction extends from the converter's inlet to its outlet.

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

[0014] The control unit can be configured to automatically calculate the required contact pressure for each pressing roller and displace each actuator to achieve 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, where the pressing rollers in each group are given the same displacement, but the displacements differ between the first group and the second group.

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

[0017] In one embodiment, the inlet section is located upstream of the alignment module, and the pressing rollers of the inlet section are spaced apart from the blank so as not to contact it, while the rest of the pressing rollers are in contact with the blank. Consequently, the pressing rollers of the guide section located downstream of the inlet section are in contact with 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 conveyance direction of the blank, and to move the pressing roller of the inlet section away from the blank.

[0019] In one embodiment, a connecting structure is disposed between the pressing roller and the linear frame member. The connecting 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 connecting 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 separated 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] Thus, the pressing roller does not contact the blank. As a result, the box can exit the feeder before entering the alignment module provided 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 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] It is a schematic view of a converter of the configuration of a folding-gluing machine. [Figure 2a] This is a top view of the blank. [Figure 2b] This is a top view of a folding box. [Figure 3] This is a schematic perspective view of a conventionally known alignment module. [Figure 4] This is a schematic cross-sectional side view of an alignment device according to an embodiment of the present invention, viewed from a first side. [Figure 5] This is a schematic cross-sectional side view of the alignment device shown in Figure 4, viewed from a second side. [Figure 6a] This is a schematic perspective view of the alignment device shown in Figure 4, viewed from the first side. [Figure 6B] This is a schematic perspective view of the alignment module shown in Figure 4 from a second side. [Figure 7] This is a schematic perspective view of the left and right alignment devices. [Figure 8a] This is a detailed view of the upper pressing member of the alignment device according to an embodiment of the present invention. [Figure 8b] This is a detailed view of the upper pressing member of the alignment device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0033] Refer in detail to Figure 1, which shows a converter 1 in the form of a folding-gluing machine 1, and to Figures 2a and 2b, which show a blank 2 and a folding box 2' processed by the converter 1. The folding-gluing machine 1 is configured to receive a cut portion, form a blank 2 as shown in Figure 2b, and then fold and glue the blank 2 to form a folding box 2' or other folding-glued packaging container 2'. To enable folding, the blank 2 has longitudinal fold lines 4 extending in the transport direction T of the blank 2.

[0034] Blank 2 has a longitudinal length Lb in the transport direction T. In the case of Blank 2 having irregular leading edge 3a and trailing edge 3b, the longitudinal length Lb is the maximum length of Blank 2 in the transport 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 may 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 transport direction T. The folding-gluing machine 1 may further include a main user interface 13 and a quality control system 18.

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

[0037] The converter 1 further comprises a conveying system 19 equipped with 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 located downstream of the feeder unit 10 in the transport 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 is disclosed in U.S. Patent No. 7,398,872 and may have a mechanical structure similar to the alignment module shown in Figure 3. This mechanical structure comprises an upper pressing member 22 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 positioned at a predetermined angle in the transport direction T so as to guide the side edges L and R of the blank 2 in contact with the guide 26. The guide 26 is positioned so that its longitudinal extension L coincides with the transport direction T. Therefore, the transport direction T is defined by the guide 26 within the alignment module 11.

[0041] The alignment conveyor 24 consists 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 Figures 4 and 5, according to the present invention, at least a portion of the pressing rollers 42 is connected to their respective actuators 54. Therefore, the dedicated actuators 54 are connected to at least a portion of the pressing rollers 42. The actuators 54 are configured to provide vertical displacement to the pressing rollers 42, and are capable of setting the contact pressure with respect to the blank 2. In a preferred embodiment, each of the pressing rollers 42 of the alignment module 11 is displaceable by its respective actuator 54.

[0043] However, it is also possible to make only a portion of the pressing roller configuration displaceable by the actuator 54. In this embodiment, some of the pressing rollers 42 can be manually moved or fixed in position.

[0044] The alignment module 11 may further comprise an inlet section I. The inlet 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 rollers 42 of the inlet section I to zero or at least lower than that of the guide section G of the pressing member 22, so that the pressing member 22 does not change the trajectory of the blank 2 in the inlet section I. This allows the alignment module 11 to accept the full length lateral length Lb of the blank 2 before biasing the blank 2 laterally. This also allows the blank 2 to exit the feeder module 10 before its trajectory is changed. Optionally, some of the pressing rollers 42 in the inlet section can be fixed or manually movable.

[0045] The length of the entrance section can be configured such that the blank 2 is moved laterally only when its total length in the longitudinal direction, Lb, 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 comprises 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 Figure 7, the converter 1 preferably comprises a first alignment device 25a and a second alignment device 25b. The first alignment device 25a is configured to contact the left side L of the blank 2, and the second alignment device 25b is configured to contact the right side R of the blank 2. However, the first and second alignment devices 25a and 25b are not used simultaneously. Instead, the first and second alignment devices 25a and 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 convenient to align with the guide 26 than an irregular side edge.

[0048] When one alignment device is activated, the other device is deactivated. In the deactivated alignment device, the pressure roller 42 can be moved upward and away from the blank 2, and the pressure roller 42 of the deactivated alignment device is set so as not to contact the blank 2. Alternatively, the contact pressure of the pressure roller 42 is set so that the pressure roller 42 contacts the blank 2 but does not apply enough force to change the trajectory of the blank 2. In addition, the lower alignment conveyor 24 of the deactivated alignment device can be moved to a position straight in the transport direction T. Guides 26 are positioned in the activated alignment devices 25a and 25b.

[0049] The pressure roller 42 can rotate freely. As is best seen in Figures 6a, 8a, and 8b, the pressure roller 42 preferably includes an elastic contact surface 44. For example, the contact surface 44 may include rubber.

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

[0051] Multiple cantilever extensions 50 are attached to a 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. Therefore, the cantilever extensions 50 extend parallel to each other, preferably in a horizontal direction.

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

[0053] As shown in Figure 8b, the actuator 54 includes a displacement rod 55 having a tip 57 connected to a pivotable lever 52. A pressure roller 42 can be elastically attached to the displacement rod 55. A spring member 58 is configured to displace the pressure roller 42 away from the conveyor belt 23. Thus, the spring member 58 displaces to counteract the pressure applied by the actuator 54. The spring member 58 can be a compression spring 58 positioned around the displacement rod 55 of the actuator 54.

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

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

[0056] As the actuator rod 55 extends, the pressure roller 42 traces a circular orbit relative 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 produce a vertical displacement component that is larger than the horizontal displacement. The length L1 can be measured as the distance from the central pivot point 53 to the axis of rotation 49 of the pressure roller 42.

[0057] Each actuator 54 is connected to a separate fluid circuit 60 (see Figure 7). The fluid pressure in each fluid circuit 60 can be changed so that a displacement rod 55 moves to adjust the contact pressure of each pressure roller 42 on the blank. This allows the contact pressure of the pressure rollers 42 to be changed according to the thickness and compressibility of the blank 2. The fluid circuit 60 is preferably operable individually for each pressure 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 supply air to each actuator 54.

[0058] Preferably, the fluid pressure in each fluid circuit 60 can be individually changed to either activate or deactivate the pressure rollers 42. Activating means that the pressure rollers 42 are applying pressure to the blank 2. Deactivating means that the pressure rollers 42 are not applying pressure to the blank 2, preferably so that there is no contact between the deactivating pressure rollers 42 and the blank 2. Preferably, the fluid pressure in the inlet section is the same for all pressure rollers 42 located in the inlet section. Therefore, the pressure applied by the pressure rollers 42 in the inlet section can be zero. The fluid pressure of the activated pressure rollers 42 may be the same for all pressure rollers 42 located in the guide section G.

[0059] The actuator 54 can operate automatically based on commands from the control unit 32. Commands can be manually entered into the user interface 13. However, it is preferable that the commands be presented by calculated setpoints provided by the control unit 32. Such calculations may be based on multiple calibration parameters.

[0060] 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. Material properties such as elastic deformation characteristics related to material density can also be selected as calibration parameters.

[0061] In some cases, the type of blank 2 to be processed may be repeated as appropriate, and a set of stored setting parameters can be selected from the operator interface 13 and read from 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 to the central control circuit 20 of the converter 1. The calibration parameters can be included in a dataset contained in a processing file. Such a dataset can be input to the central control circuit 20 of the converter 1 either remotely or manually. Physical input includes inputting certain hardware, such as a data cable or flash drive, into the communication port of the converter 1. Remote input can be performed from a remote computing location 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 and R of blank 2. This can be selected manually by the operator. Alternatively, the control unit 32 can perform calculations to determine which side is best suited for alignment.

[0064] The control unit 32 is configured to selectively operate either 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] Memory 34 contains a program having an algorithm that enables the control unit 32 to calculate the required contact pressure from each pressure roller 42. The algorithm is configured 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 entrance section and determine which pressure rollers 42 need to be deactivated and moved away from the blank 2.

Claims

1. An alignment module (11) for lateral alignment of blanks (2) within a converter (1), The alignment module includes a first alignment device (25a) comprising an upper pressing member (22) having a plurality of pressing rollers (42), and a lower alignment conveyor (24) including an electrically operated alignment conveyor belt (23) and a guide (26). The alignment module is configured to receive the blank between the upper pressing member and the lower alignment conveyor and to transport the blank toward the guide, the pressing rollers are connected to a linear frame member (46), at least some of the pressing rollers are connected to their respective actuators (54), the actuators are configured to displace the pressing rollers (42) in the vertical direction (V), the alignment module further comprises a control unit (32) and a memory (34), the control unit is configured to determine a required displacement for each of the pressing rollers and to actuate each of the actuators to perform the required displacement, Alignment module 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 detached position where they do not come into contact with the blank.

2. The alignment module according to claim 1, wherein all of the pressing rollers (42) are connected to each of the actuators (54), and all of the pressing rollers (42) are configured to be displaced vertically by each of the actuators.

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

4. The alignment module according to claim 1 or 2, wherein 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, the displacement being different for the first and second groups.

5. The alignment module according to claim 4, wherein 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.

6. The alignment module according to claim 5, wherein the inlet section (I) is provided upstream of the alignment module, 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 is in contact with the blank.

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

8. The alignment module according to claim 1 or 2, wherein a connecting structure (48) is positioned between the pressing roller and the linear frame member, and the connecting structure comprises a plurality of cantilever extensions (50) and pivot levers (52), and each of the pivot levers interconnects the pressing roller to the cantilever extension.

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

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

11. The alignment module according to claim 1 or 2, wherein the actuator is a pneumatic actuator and is connected to a pneumatic circuit (60).

12. The alignment module according to claim 11, wherein 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.

13. The alignment module according to claim 1 or 2, wherein the control unit is configured to calculate the required displacement of the pressing roller from 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 relating to the pressing roller from the longitudinal length (Lb) of the blank.

15. The alignment module according to claim 1 or 2, wherein the vertical position of the pressing roller can be adjusted from a control interface.

16. The alignment module according to claim 1 or 2, wherein the memory is configured to store the length and contact pressure of the inlet section and to make them readable from the user interface (13).

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