Suction bar system for converters

Abstract

The present invention relates to a suction bar system for a converter (10), the suction bar system comprising at least one suction bar assembly (31) comprising a suction plate (36) mounted on a cross beam having an internal air supply passage (34). The suction plate (36) comprises a plurality of main air passages (48), each of which has a first suction opening (46a) and a second suction opening (46b). The main air passages (48) comprise a constricted section (S2) having a first connecting duct (50) configured to create a pressure drop across the first suction openings (46a).

Description

Technical Field

[0006]

[0001] The present invention relates to a converting machine for manufacturing boxes and packaging blank materials. Specifically, it relates to a suction bar system configured to hold a blank material in a converting machine.

Background Art

[0002] Converting machines are used in the manufacture of packaging items such as paperboard and corrugated boxes. A platen printing machine is a converting machine that can be configured to process blank materials such as paperboard and corrugated sheets. Specifically, a platen printing machine is configured to punch out box and packaging element blank materials from a sheet. Also, a platen printing machine is sometimes called a "die cutter".

[0003] A platen printing machine includes a plurality of processing units or stations. A conveyor system is provided in such a machine to hold the blank material and transfer it from one processing unit to the next.

[0004] The conveyor system helps position the sheet so that the processing operations are performed at the correct positions on the blank material. The conveyor system can include a gripping bar configured to grasp the leading edge in front of the blank material. The gripping bar holds the blank material in the correct vertical and horizontal positions and conveys the blank material according to a preset timing.

[0005] However, it is also desirable to hold the trailing edge at a predetermined position with a suction plate to prevent the sheet from bending or deforming. When the speed of the gripping bar changes, the blank material tends to bend during deceleration.

[0006] International Publication No. 20245116 discloses a suction plate for holding the trailing edge of a sheet as it is transported through a platen printing press. The suction plate comprises a line having multiple air vents arranged side by side. However, the suction plate needs to be positioned at a specific vertical distance from the blank material in order to hold the blank material in place. Problems arise when the dimensions and thickness of the blank material change, and the distance from the blank material to the suction plate increases. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 20245116 [Overview of the project] [Problems that the invention aims to solve]

[0008] In view of the above-mentioned problems, an object of the present invention is to provide a suction bar assembly having an improved ability to grip and hold the trailing edge of a sheet, wherein the suction force is adapted to hold sheets of various dimensions. [Means for solving the problem]

[0009] This objective is achieved by the suction bar system described in claim 1 and the positioning system described in claim 14.

[0010] According to a first aspect of the present invention, a suction bar system for a converter is provided, the suction bar system comprising at least one suction bar assembly having a suction plate mounted on a crossbeam having an internal air supply channel.

[0011] The suction plate has a suction surface configured to apply suction force to the blank material being transported in the conveying direction through the converter. The suction plate has multiple main air passages, each main air passage having an air inlet connected to an air supply passage and an air outlet, and the flow direction extends between the air inlet and the air outlet. Each of the main air passages comprises a first suction opening and a second suction opening, the suction openings being located on a suction surface, and the main air passages further comprise a constricted section having a first connecting duct connected to the first suction opening, the constricted section being configured to generate a pressure drop at the first suction opening.

[0012] This invention is based on the recognition that gripping a blank material with a suction plate can be improved and performed quickly by first reducing the air volume present between the suction plate and the blank material and then applying a strong localized suction force to the trailing edge of the blank material.

[0013] In one embodiment, the main airflow channel has a cross-sectional area in the flow direction upstream of the second suction opening that is larger than the cross-sectional area of ​​the constricted section. The suction bar system is designed to generate airflow from the combined inlet airflow and airflow from the first suction opening, so that a large volume of air is injected through the main airflow channel at the second airflow opening. Thus, this combined airflow passes through the connecting section to the second air opening, generating a high suction volume through the second air opening.

[0014] In one embodiment, the first and second suction openings are arranged on separate lines perpendicular to the transport direction T. Thus, the lines are arranged along the longitudinal direction of the crossbeam.

[0015] In one embodiment, the constricted section of the main airflow channel is a venturi section.

[0016] Preferably, the second suction opening is connected to the main airflow path via a second connecting duct. Preferably, the connecting duct to the first suction opening is located upstream of the connecting duct to the second suction opening in the flow direction.

[0017] In one embodiment, the first suction opening is located further downstream in the conveying direction than the second suction opening.

[0018] The internal air supply flow path can have an inlet end connected to the air flow generator and can include a plurality of distribution outlet openings configured to coincide with the air inlet openings of the suction plate.

[0019] Preferably, the suction plate is a separate part and is removably attached to the cross beam.

[0020] In one embodiment, the first suction opening is arranged at a predetermined distance from the second suction opening, and the distance is less than 10 times the diameter of the main air flow path at the second suction opening.

[0021] The distance between the first suction opening and the second suction opening may vary between the main flow paths.

[0022] For example, each suction opening can be arranged in a staggered pattern such that the suction surfaces have a regular arrangement. This means that the length of the distance section can be different for a part of the main flow path.

[0023] In one embodiment, the suction bar system can further include a deflection flange, and the outlet opening of the main air flow path is located below the deflection flange.

[0024] In one embodiment, the suction bar system can further include a displacement mechanism including first and second slide rails, and the suction plate is slidably attached to the slide rails.

[0025] According to a second aspect of the present invention, a positioning system including a suction bar system and a gripping unit is provided. The gripping unit is configured to grip and position the front edge in front of the blank material, and the suction bar system is positioned such that the first suction opening is located further upstream in the conveying direction than the second suction opening.

[0026] In one embodiment, the positioning system includes a plurality of suction bar assemblies arranged along the conveying direction. Accordingly, the suction bar assemblies are arranged at each workstation and configured to hold the trailing edge of the blank material.

[0027] Hereinafter, the present invention will be described with reference to the accompanying drawings in which like reference numerals are given to like features.

Brief Description of the Drawings

[0028] [Figure 1] It is a schematic cross-sectional view of the converter in the platen printing mechanism. [Figure 2] It is a schematic perspective view of a suction bar assembly according to an embodiment of the present invention. [Figure 3] It is a schematic perspective view having a cutaway portion showing the suction plate for the suction bar assembly of FIG. 2. [Figure 4A] It is a schematic perspective view of the suction bar assembly attached to the converter. [Figure 4B] It is a detailed cross-sectional view of the suction plate coupled to the air flow duct.

Embodiments for Carrying Out the Invention

[0029] The present invention is described in relation to a platen printing machine converter. However, the present invention can be incorporated into other types of printing modules and folding modules for the converter and can be used to stabilize sheets and blank materials during conveyance.

[0030] Referring to Figure 1, a converter 10 in the form of a platen printing press is shown. The platen printing press 10 is configured to transform a sheet 12 into a blank material 12. Thus, the sheet 12 is transformed into a final blank material 12 as it is transported through the converter 10. In relation to this application, the term “blank material” is used for the initial sheet 12 attached to the converter 10, the intermediate blank material 12 in the converter 10, and the final blank material 12 produced by the converter 10.

[0031] The converter 10 is composed of multiple workstations or units, each performing a specific operation on the blank material 12. In the transport direction T of the blank material 12, the converter 10 includes a supply unit 10a, a platen printing unit 10b, a removal unit 10c, a blanking unit 10d, and a waste discharge unit 10e.

[0032] Subsequently, the blank material 12 can be recovered from the platen printing press 10 and introduced into a folding-gluing converter, where the blank material 12 is automatically glued and folded to form a folding box. Alternatively, the blank material 12 from the platen printing press 10 can be used as a flat-packed box and can be folded manually.

[0033] The supply unit 10a is configured to receive a stack of blank material 12 and supply them one by one to the platen printing unit 10b. The blank material 12 may have text or decorations pre-printed on it. Alternatively, the blank material 12 may not have any printable features. The platen printing unit 10b is equipped with a die-cutting tool that has cutting rules and creasing rules configured to cut and fold the sheet 12.

[0034] The removal unit 10c is configured to remove specific waste elements from the cut sheet 12. The blanking unit 10d is positioned behind the removal unit in the transport direction T and is configured to separate the blank material 12 from the cut waste and to stack and arrange the blank material 12.

[0035] Following the blanking unit 10d, the waste discharge unit 10e is configured to remove further waste elements from the cut sheet 12. The waste discharge unit 10e may include a conveyor to move the waste away from the platen printing machine.

[0036] The blank material 12 is transported through the converter 10 by a conveyor system 18, which includes a conveyor belt 20 to which multiple gripping units 22 are attached. The gripping units 22 can also be called "gripping bars" 22. The gripping units 22 are configured to grip the leading edge 12' of the blank material 12 and transport the blank material 12 through the converter 10 in a guided manner. The gripping units 22 release the molded blank material 12 at the blanking unit 10d. The gripping units 22 are spaced apart from each other at a fixed distance, and the distance between the leading edges 12' of the blank material 12 is also fixed. The conveyor belt 20 is positioned above the blank material 12 and follows a trajectory above the transport path of the blank material 12. The gripping units 22 transport the blank material 12 between different workstations and momentarily stop the blank material 12 when the platen printing unit 10b collides with it.

[0037] The trailing edge 12'' of the blank material 12 is held by a suction bar system 30 comprising at least one suction bar assembly 31. The suction bar system 30 may comprise multiple suction bar assemblies 31. Preferably, the suction bar system 30 is located on the opposite side of the conveyor belt 20, which comprises the gripping unit 22. In this way, interference and space constraints between the two systems 18, 30 can be reduced. In the illustrated embodiment, the suction bar system 30 is located below the blank material 12.

[0038] Therefore, the converter 10 may be equipped with a suction bar assembly 31 in each of the platen printing unit 10b, the removal unit 10c, and the blanking unit 10d. Each suction bar assembly 31 is positioned in its respective workstation to hold the trailing edge 12'' of the blank material 12. Thus, the trailing edge 12'' of each blank material 12 moving through the converter 10 is held by the suction bar assembly 31 when the processing operation is performed on the blank material 12.

[0039] The gripping unit 22 moves through different workstations and performs a return path from the blanking unit 10d back to the platen printing unit 10b. The suction bar assembly 31 is fixed and positioned upstream of each workstation 10b, 10c, and 10d.

[0040] As is best seen in Figure 4a, the position of the suction bar assembly 31 is preferably adjustable in the transport direction T. In this way, the position of the suction bar assembly 31 can be adapted to the longitudinal length L1 of the blank material 12. Displacement mechanisms 35 in the form of a first slide rail 35a and a second slide rail 35b can be positioned at the distal ends 31a, 31b of the suction bar assembly 31 and can engage with cooperative connecting components on the suction bar assembly 31.

[0041] Therefore, the blank material 12 is held firmly and evenly between the gripping unit 22 and the suction bar assembly 31. This ensures that the punching operation performed by the platen printing unit 10b results in cutting lines and fold lines in the correct positions, and as a result the geometry of the cut blank material 12 is accurate.

[0042] The combination of the gripping unit 22 and the suction bar assembly 31 forms a positioning system.

[0043] As shown in Figure 2, each suction bar assembly 31 includes an elongated crossbeam 32 having an internal air supply conduit 34 and a suction plate 36 having a suction surface S.

[0044] The suction surface S of the suction plate 36 is configured to apply a suction force to the blank material 12 such that its trailing edge 12'' adheres to it. The suction surface S on the suction plate 36 is provided with a plurality of suction openings 46 configured to apply a suction force to the blank material 12.

[0045] Preferably, only a portion of the longitudinal length L1 of the blank material 12 comes into contact with the suction surface S. The rear portion of the blank material 12, which is approximately 75% of the longitudinal length L1 in the transport direction T, can come into contact with the suction surface S during deceleration of the blank material 12. Therefore, the front portion of the blank material 12, which is approximately 25% of the longitudinal length L1, does not come into contact with the suction surface S.

[0046] This allows the blank material 12 to close the first suction opening 46a of the suction surface S and grip the rear of the blank material 12. Thus, the blank material 12 is slowed down and straightened because the suction surface S grips the blank material 12. The first suction opening 46a is located at the rear edge of the blank material, near the position where the blank material 12 is momentarily stopped. In one embodiment, the position of the first suction opening 46a is at a distance between 0 mm and 50 mm from the rear edge of the blank material 12, at the position where the blank material 12 is momentarily stopped.

[0047] The blank material 12 is positioned at a predetermined perpendicular distance from the suction surface S of the suction plate 36. This perpendicular distance is measured between the suction surface S and the blank material 12 at the mounting position to the gripping unit 22. The distance between the suction surface S and the blank material 12 can be up to 16 mm. This ensures that the suction force used to attach the blank material 12 to the suction bar assembly 31 is sufficient to hold the blank material 12 flat.

[0048] The suction plate 36 is attached to the elongated crossbeam 32. The connection between the suction plate 36 and the elongated crossbeam 32 can be made by fasteners 38, such as screws, bolts, or rivets 38. The suction plate 36 can be detachably attached to the elongated crossbeam 32.

[0049] The suction plate 36 can be manufactured by an additive manufacturing process, i.e., a 3D printing process. This allows for the formation of complex internal air channels within the suction plate 36. Alternatively, the suction plate 36 can be manufactured by other conventional manufacturing methods, including sheet metal forming or metal machining with tools.

[0050] In the embodiment shown in Figure 2, multiple suction plates 36 are mounted on the upper surface of the elongated crossbeam 32. However, it is also possible to provide a single suction plate 36 that extends along the length of the elongated crossbeam 32 in the longitudinal direction L. The longitudinal direction L and the longitudinal extension of the suction bar assembly 31 are perpendicular to the conveying direction T.

[0051] The air supply conduit 34 includes an air inlet 33 connected to an airflow generator (not shown). Multiple air outlet openings 40 are arranged on the upper surface of the elongated crossbeam 32. The air outlet openings 40 from the air supply conduit 34 are configured to coincide with the air inlet openings 42 (see Figure 3) to which the suction plate 36 is joined. Preferably, a seal 44 is positioned between the air supply conduit 34 and the suction plate 36. The seal 44 has an opening where the air outlet opening 40 coincides with the air inlet opening 42.

[0052] The suction opening 46 comprises a first group of suction openings 46a and a second group of suction openings 46b. The first and second groups of suction openings 46a and 46b can be positioned to coincide with a linear extension that coincides with the longitudinal extension of the suction bar assembly 31.

[0053] Alternatively, the first suction opening 46a can be arranged in a staggered pattern on the longitudinally extended portion of the suction bar assembly 31. In this way, the suction surface S has a regular arrangement of suction openings 46a and 46b. This can be achieved by providing a varying distance d1 (see Figure 3) between the first suction opening 46a and the second suction opening 46b. The second suction opening 46b can also be arranged in a staggered pattern.

[0054] The first and second groups of suction openings 46a and 46b can be positioned upstream of each workstation. This allows the gripping unit 22 to position the front edge of the blank material 12 at the exit of each workstation while the suction openings 46a and 46b apply suction force to grip the rear edge of the blank material 12. The first group of suction openings 46a is configured to apply suction force to the blank material 12 so that the blank material 12 adheres to the suction surface S of the suction bar assembly 31. Preferably, the first group of suction openings 46a is positioned further downstream than the second group of suction openings 46b in the transport direction T. The suction force is selected to keep the blank material 12 flat and prevent the rear edge of the blank material 12 from lifting.

[0055] The second group of suction openings 46b is configured to generate a large amount of air intake in order to reduce the amount of air located between the blank material 12 and the suction bar assembly 31 by suction.

[0056] The pressure is lower for the group of first suction openings 46a than for the group of second suction openings 46b. In one embodiment, the pressure of the first suction opening 46a can be between 0 mbar and -600 mbar, preferably between -40 mbar and -200 mbar. The pressure of the second suction opening 46b is between 0 mbar and -150 mbar, preferably between 0 mbar and -40 mbar.

[0057] This pressure difference is achieved by a specific flow path design of the suction plate 36. As is best seen in Figure 3, the suction plate 36 has multiple main air passages 48 extending from an inlet opening 42 to an outlet opening 43. The inlet opening 42 is connected to the central air supply conduit 34 as described above. The outlet opening 43 can be located below the flange 47 of the suction bar assembly 31. The flange 47 can be in the form of a plate element and can be configured to divert the outlet airflow away from the main air passages 48.

[0058] The airflow rate through the first suction opening 46a and the second suction opening 46b can be up to 3000 liters / minute.

[0059] Each main air passage 48 has a plurality of sections S1 to S6 having different shapes in the airflow direction F. In the direction from the inlet opening 42 to the outlet opening 43, the main air passage 48 comprises an inlet section S1, a constriction section S2, a first connecting section S3, a distance section S4, a second connecting section S5, and an outlet section S6.

[0060] The inlet section S1 can be curved so that its inlet opening 42 is perpendicular to the air supply opening 40 of the suction bar assembly 31. The inlet section S1 can guide the inlet airflow Q1 into the main airflow channel 48. The inlet airflow Q1 is received in the inlet section S1. The pressure in the inlet section S1 is similar to the pressure in the air supply channel 34, and the airflow velocity v1 is selected with respect to the cross-sectional area of ​​the inlet section S1.

[0061] The constricted section S2 is a venturi section configured to accelerate the airflow so that the airflow velocity increases. The constricted section S2 is funnel-shaped such that the cross-sectional area of ​​the main airflow channel 48 gradually decreases in the airflow direction F. The airflow velocity v2 in the constricted section S2 is higher than the airflow velocity v1 in the inlet section S1, while the pressure in the constricted section S2 is reduced to be lower than that in the inlet section S1. The flow rate Q2 through the constricted section S2 is equal to the flow rate Q1 in the inlet section S1.

[0062] The first connection section S3 includes a connecting duct 50 extending from the main air passage 48 to the first suction opening 46a. The inlet of the first connection section S3 is located at the outlet of the constricted section S2. Thus, the first suction opening 46a is connected to the outlet of the constricted section S2. The pressure reduction at the outlet of the constricted section S2 causes a pressure drop in the first connecting duct 50. This generates a suction force through the first suction opening 46a.

[0063] As a result, the additional airflow Q2 is drawn into the main airflow channel 48 through the first suction opening 46a. This results in an increase in the airflow in the connecting section S3. The airflow Q3 passing through the first connecting section S3 is equal to the sum of Q1 and Q2. Furthermore, the connecting section S3 has a larger cross-sectional area than the constricted section.

[0064] The distance section S4 has a substantially constant cross-sectional area and ensures that the first suction opening 46a is separated from the second suction opening 46b by a distance d1. The distance d1 can be selected to be long enough to reduce airflow turbulence at the end of the distance section S4. Preferably, the distance d1 is less than 10 times the diameter d2 of the main airflow channel 48 at the second suction opening 46b.

[0065] The second connection section S5 to the second suction opening 46b is located at the outlet of the distance section S4. The cross-sectional area of ​​the distance section S4 is larger than that of the inlet section S1, and the airflow Q5 through the second connection section S5 is larger than that of the inlet airflow Q1. This results in a high air intake Q4 through the second suction opening 46b. In one embodiment, there may be multiple second suction openings 46b connected to each main airflow path 48.

[0066] The outlet section S6 is configured to divert the airflow through the outlet opening 43. The airflow Q5 of the outlet section S6 is the sum of the inlet airflow Q1 and the airflows Q2 and Q4 supplied through the first and second suction ports 46a and 46b. [Explanation of Symbols]

[0067] 10 Converters 12 Blank materials 30 Suction Bar System 31 Suction bar assembly 32 Crossbeam 34 Internal air supply channel 36 Suction Plate 48 Main air passage 42 Air Inlet 43 Air outlet 46a First suction opening 46b Second suction opening 50 First connecting duct F flow direction S suction surface S2 Constriction Section

Claims

1. A suction bar system (30) for a converter (10), The suction bar system comprises at least one suction bar assembly (31) including a suction plate (36) mounted on a crossbeam (32) having an internal air supply passage (34), The suction plate has a suction surface (S) configured to apply a suction force to the blank material (12) that is transported in the transport direction (T) through the converter (10), A suction bar system comprising a suction plate (36) having a plurality of main air passages (48), each of which has an air inlet (42) connected to the air supply passage (34) and an air outlet (43), the flow direction (F) extending between the air inlet (42) and the air outlet (43), each of which has a first suction opening (46a) and a second suction opening (46b), the suction openings (46a, 46b) provided on the suction surface (S), and the main air passage (48) having a constricted section (S2) having a first connecting duct (50) connected to the first suction opening (46a), the constricted section being configured to generate a pressure drop at the first suction opening (46a) but not at the second suction opening (46b).

2. The suction bar system according to claim 1, wherein the main air passage has a cross-sectional area (A2) on the upstream side in the flow direction (F) of the second suction opening (46b) that is larger than the cross-sectional area (A1) of the constricted section (S2).

3. The suction bar system according to claim 1 or 2, wherein the first and second suction openings (46a, 46b) are arranged in separate lines perpendicular to the transport direction (T).

4. The suction bar system according to claim 1, wherein the constricted section (S2) of the main air passage is a venturi section.

5. The suction bar system according to claim 1, wherein the second suction opening (46b) is connected to the main air passage via a second connecting duct (51).

6. The suction bar system according to claim 5, wherein the connecting duct (50) to the first suction opening is located upstream of the connecting duct (51) to the second suction opening in the flow direction (F).

7. The suction bar system according to claim 1, wherein the first suction opening (46a) is located further downstream than the second suction opening (46b) in the transport direction (T).

8. The suction bar system according to claim 1, wherein the internal air supply channel (34) has an inlet end (33) connected to an airflow generator and comprises a plurality of distribution outlet openings (40) configured to coincide with an air inlet opening (42) on the suction plate.

9. The suction bar system according to claim 1, wherein the suction plate is a separate component and is detachably attached to the crossbeam.

10. The suction bar system according to claim 1, wherein the first suction opening is located at a distance (d1) from the second suction opening, and the distance is less than 10 times the diameter (d2) of the main air passage at the second suction opening.

11. The suction bar system according to claim 1, wherein the distance (d1) between the first suction opening and the second suction opening is different between the main air passages.

12. The suction bar system according to claim 1, further comprising a deflection flange (47), wherein the air outlet (43) of the main air passage is located below the deflection flange.

13. The suction bar system according to claim 1, further comprising a displacement mechanism (35) including first and second slide rails (35a, 35b), wherein the suction plate is slidably mounted on the slide rails.

14. A positioning system comprising a suction bar system according to claim 1 and a gripping unit, wherein the gripping unit (22) is configured to grip and position the front edge of a blank material, and the suction bar system is positioned such that the first suction opening (46a) is located further downstream than the second suction opening (46b) in the transport direction.

15. The positioning system according to claim 14, wherein a plurality of suction bar assemblies (31) are arranged along the transport direction (T).

Images