Feeder module

Abstract

The invention relates to a feeder module for a conversion machine, the feeder module comprising an upper feeder assembly and a lower feeder assembly, the lower feeder assembly comprising a loading surface configured to receive a stack of sheets. The upper feeder assembly (20) includes a measuring instrument (32) wherein the distance (d1) between the vertical distal end of the measuring instrument and the loading surface defines a gap through which the lowermost sheet in the stack can pass at a time. A feed roller assembly (34) downstream of the measuring instrument includes an upper feed roller (35a) and a lower feed roller (35b). The lower feeder assembly (22) and the lower feed roller are movable in a vertical direction.

Description

Technical Field

[0001] The present invention relates to a feeder module for a converting machine such as a rotary printing press. The present invention also relates to a converting machine or digital printing press configured to print and convert sheet elements into packaging elements. Background Art

[0002] Converting machines are used in the production of packaging elements such as flat packs and folded boxes. Sometimes the same converting machine is configured to print, cut, crease and fold sheets to form packaging elements.

[0003] However, it is also common to use several types of converting machines when producing packaging elements. For example, a first machine prints the sheet substrate and a second machine cuts the sheet to form cut-to-shape blanks. Sometimes, the second machine may also glue and fold the blanks.

[0004] A common module of these conversion machines is a feeder module. The feeder module includes a loading surface on which a stack of sheets can be placed. The feeder module is configured to discharge the sheets one by one into the conversion machine in a precisely timed manner in the direction of transport. The feeder module also includes a gauge that defines a gap that allows only one sheet to enter the conversion machine at a time. A pair of feed rollers are usually arranged on the downstream side of the feeder gauge, which clamp the leading edge of the sheet and pull the sheet out of the loading surface.

[0005] Examples of feeder modules equipped with feed rollers are described in documents US Pat. No. 3,907,278 and US Pat. No. 5,074,539.

[0006] Converting machines are used for different thickness of paperboard. Usually, the thickness of paperboard can vary between 0.7-15mm.

[0007] The trajectory of the sheet is different for cardboard sheets of different thicknesses. When the sheet passes between different machine parts that grip the sheet in an alternating manner, there is a risk that the leading edge of the sheet will bend or even warp, even if the vertical distance between the sheet and the machine part is small. Cardboard is a hard material and when it bends, permanent and visible bending marks and scratches may form. Summary of the invention

[0008] The object of the present invention is to alleviate the above-mentioned disadvantages of the prior art.

[0009] This object is solved by a feeder module according to claim 1 .

[0010] According to a first aspect of the invention, there is provided a feeder module for a conversion machine, the feeder module comprising:

[0011] a lower feeder assembly including a loading surface configured to receive a stack of sheets and a discharge conveyor configured to discharge the sheets in a transport direction through the converter,

[0012] - an upper feeder assembly comprising a gauge, wherein the distance between a vertical distal end of the gauge and the loading surface defines a gap through which a lowermost sheet in the stack can pass,

[0013] - a feed roller assembly comprising an upper feed roller and a lower feed roller, the feed roller assembly being located downstream of the measuring instrument, characterized in that the lower feeder assembly comprises a shifting mechanism configured to move the loading surface in a vertical direction, and wherein the feed roller assembly comprises a feed roller shifting mechanism configured to move the lower feed roller in a vertical direction.

[0014] The invention is based on the recognition that it is possible to provide a transport path for the sheets in which the upper surface of each sheet is in a constant vertical position, regardless of feeder adjustments made to accommodate different sheet thicknesses in different production batches. By connecting the feeder loading surface and the lower feed roller to a shifting mechanism, different paperboard thicknesses can be accommodated.

[0015] In the context of this application, the term "converting machine" includes machines configured only for printing sheet substrates, or converting machines that also include cutting and forming modules such as rotary die cutters, flatbed die cutters, or slotting and folding modules.

[0016] In one embodiment, the upper feeder assembly and the upper feeder rollers are in a fixed arrangement.

[0017] In one embodiment, the lower feed rollers and the loading surface are mounted in a common chassis.

[0018] In one embodiment, the lower feed rollers and the loading surface are mounted in different chassis.

[0019] In one embodiment, the feed roller shifting mechanism comprises a first shifting device and a second shifting device, and wherein the first shifting device is configured to shift the lower feed roller to a smaller distance than the second shifting device.

[0020] In one embodiment, the feeder shifting mechanism includes a motor, an actuator, and a conversion element configured to convert horizontal displacement of the lower feeder assembly into vertical displacement.

[0021] In one embodiment, the actuator is a drive screw and the transition element is a wedge-shaped transition element.

[0022] According to a second aspect of the invention, there is provided a conversion machine comprising a feeder module according to any one of the preceding claims, wherein a conveying unit is located downstream of a feed roller assembly, and wherein the conveying unit comprises a drive element having a contact surface configured to contact a sheet and a vacuum hole configured to apply suction to an upper side of the sheet, wherein an upper feed roller is aligned with the conveying element in the conveying unit.

[0023] In one embodiment, the conversion machine includes a control unit configured to determine a desired displacement of the loading surface and to actuate the feeder shifting mechanism and the feed roller shifting mechanism to achieve the desired displacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will now be described with reference to the accompanying drawings, in which like features are indicated by like reference numerals, and in which:

[0025] - Figure 1 is a schematic perspective view of a converter in a flexographic printing press configuration;

[0026] - Figure 2a is a schematic cross-sectional view of a feeder module according to an embodiment of the present invention;

[0027] - Figure 2b is a schematic cross-sectional view of a feeder module with a stack of sheets;

[0028] - Figure 3a is a schematic cross-sectional view of a loading surface of the feeder module of FIG. 2 ;

[0029] - Figure 3b is a schematic cross-sectional view of another embodiment of a loading surface of the feeder module of FIG. 2 ;

[0030] - Figure 4a and Figure 4b are side views of the discharge mechanism in a first position and a second position, respectively; and

[0031] - Figure 5 is a partial cross-sectional view of a loading surface and a discharge conveyor according to an embodiment of the present invention;

[0032] - Figure 6 is a cross-sectional view of a feeder shifting mechanism according to an embodiment of the present invention;

[0033] - Figure 7 is a top view of the discharge mechanism; and

[0034] - Figure 8 is a schematic cross-sectional view of the discharge mechanism. DETAILED DESCRIPTION

[0035] With reference to the accompanying drawings, in particular with reference to Figure 1 , which shows a conversion machine 1 in the form of a printing press. Even if not shown, the invention can also be used for other conversion machines, such as flatbed die cutters, rotary die cutters or flexographic folder-gluers, which also include a conversion unit including a slotting assembly or a rotary die cutting assembly. These machines can be equipped with the same feeder module as will be described hereinafter.

[0036] like Figure 1 As shown, the conversion machine 1 may include, in sequence along the transport direction T: a loader 10 for automatically loading a stack of sheets 2, a feeder module 12, a printing module 14 including a plurality of printing units 15, and a conveying module 16 which may include a stacker device 17. Optionally, the conversion machine 1 may also include a digital printing module (not shown).

[0037] A main operator interface 18 may also be provided near the conversion machine.The conversion machine 1 may also include strapping and palletizing modules.

[0038] like Figure 2a and Figure 2b As shown, the feeder module 12 includes an upper feeder assembly 20 and a lower feeder assembly 22. The upper feeder assembly 20 and the lower feeder assembly 22 are mounted on a common chassis 37.

[0039] The lower feeder assembly 22 includes a loading surface 24 and a discharge conveyor 25 configured to discharge the sheets 2 one by one into the converting machine 1 along the transport direction T. Figure 3a and Figure 5 As best shown, the discharge conveyor 25 may include a plurality of drive elements 30 in the form of belt conveyors 30 arranged side by side. A motor 32 is configured to drive the movement of the belt conveyors 30. Alternatively, the loading surface 24 may be provided with a plurality of drive elements 30 in the form of rollers.

[0040] The upper feeder assembly 20 includes a measuring instrument 32. The measuring instrument 32 has a distal vertical end 33, which is arranged at a distance d1 from the loading surface 24. The distance d1 between the distal vertical end 33 and the loading surface 24 defines a gap through which the lowermost sheet 2 in the stack S can pass.

[0041] The loading surface 24 is a flat surface configured to receive a stack S of sheets 2. As described in document EP2408698B1, the stack S of sheets can be placed on the loading surface 24 by a loader module 10. The loading surface 24 is attached to a chassis 37 of the feeder module.

[0042] like Figure 7As shown, the loading surface 24 may include a plurality of elongated surfaces 42. The elongated surfaces 42 are spaced apart from each other in the lateral direction L such that a slot 44 is formed between each of the elongated surfaces 42. The belt conveyor 30 is located in the slot 44.

[0043] like Figure 3a and Figure 3b As best shown, the belt conveyor 30 can be arranged in a suction box 36. The suction box 36 may include a plurality of compartments 38. The compartments 38 may be separated from each other by partition walls 40. Preferably, the partition walls 40 are arranged so that the suction compartments 38 are symmetrical with respect to the central axis A of the loading surface 24. In one embodiment, there may be two suction compartments 38, 38, which are located on each side of the central axis A. Each suction compartment 38, 38 may be connected to a separate vacuum pump (not shown). In another embodiment, there may be three suction compartments in the form of a central suction compartment 38 and a first suction compartment 38 and a second suction compartment 38. The central suction compartment 38 may be connected to a first suction pump, and both the first and second lateral suction compartments may be connected to a common second suction pump.

[0044] Each belt conveyor 30 is provided with an upper contact surface 52 in contact with the bottom surface of the sheet 2 and a return portion 54 located vertically below the contact surface 52. Therefore, the upper contact portion 52 of the belt conveyor 30 is exposed to the sheet 2 in the elongated groove 44.

[0045] The belt shift mechanism 50 is configured to uniformly move the belt conveyor 30 between a discharge position DP, where the contact surface 52 of the belt conveyor 30 is located vertically above the loading surface 24, and a cleaning position CP, where the contact surface 52 of the belt conveyor 30 is located vertically below the loading surface 24. At the discharge position DP, the lowermost sheet 2 in the stack S contacts the belt conveyor 30, which drives the sheet 2 forward in the transport direction T.

[0046] Each belt conveyor 30 is mounted on a belt guide mechanism 48. The belt guide mechanism 48 includes a drive roller 56 and an idler roller 58 around which the belt is mounted. The drive roller 56 and the idler roller 58 are rotatably attached to the chassis of the feeder module 12 in a first bracket 60a and a second bracket 60b.

[0047] The drive rollers 56 may be connected to a common drive shaft 62 that extends through the center of all of the drive rollers 56. In this manner, all of the belt conveyors 30 are driven in unison.

[0048] Preferably, the drive roller 56 and the idler roller 58 have the same diameter. In this way, the track of the belt conveyor is symmetrical. The drive roller 56 and the idler roller 58 can be toothed and configured to engage with the inner concave surface of the belt conveyor 30.

[0049] like Figure 8 As best shown, the belt shifting mechanism 50 includes a shifting member 64 located inside the inner periphery of each belt conveyor 30. The shifting member 64 includes an upper shifting surface 65a and a lower shifting surface 65b. The upper shifting surface 65a is configured to move the upper contact surface 52 of the belt conveyor 30 upward. The lower shifting surface 65b of the shifting member 64 is configured to move the return portion 54 of the belt conveyor 30 vertically downward.

[0050] The upper displacement surface 65a and the lower displacement surface 65b are preferably parallel to each other. The upper displacement surface 65a and the lower displacement surface 65b can be horizontal. The upper displacement surface 65a and the lower displacement surface 65b are preferably connected to each other via at least one vertical member 66a, 66b. However, preferably, a first vertical member 66a and a second vertical member 66b are provided. The at least one vertical member 66a, 66b can extend across the loading surface so that all upper displacement surfaces 65a and lower displacement surfaces 65b of all belt conveyors 30 are interconnected.

[0051] At least the upper displacement surface 65a may be provided with holes 68. In this way, the airflow from the suction box 36 may flow through the displacement member 64. The upper displacement surface 65a may also be provided with a sliding surface configured to contact the belt conveyor 30. The sliding surface is a low friction surface, such as a smooth metal surface.

[0052] The shifting mechanism 50 may include a motor 72 , an eccentric shaft 76 , a toothed drive roller 74 , a pulley 73 , and an eccentric shaft bracket 78 connected to a bracket 80 of the shifting mechanism 64 .

[0053] The upper displacement surface 65a and the lower displacement surface 65b are symmetrically positioned relative to the drive roller 56 and the idler roller 58. Therefore, the displacement member 64 symmetrically supports the upper contact portion 52 and the return portion 54 of the belt conveyor 30. The up and down movement of the displacement member 64 is preferably the same distance. This makes the length change of the belt conveyor 30 on either side of the displacement member 64 the same, thereby limiting the change in belt tension.

[0054] Return to reference Figure 1 and Figure 2a, the upper feeder assembly 20 and the lower feeder assembly 22 are mounted to the chassis 37. The lower feeder assembly 22 is vertically movable relative to the upper feeder assembly 20. This allows the distance d1 between the vertical distal end 33 of the measuring instrument 32 and the loading surface 24 to be changed. Therefore, the distance d1 can be changed without moving the upper feeder assembly 20 and the measuring instrument 32.

[0055] The vertical displacement of the lower feeder assembly 22 is provided by the feeder shifting mechanism 86. Figure 6 As shown in the embodiment of the present invention, the feeder shifting mechanism 86 may include a motor 88, an actuator 90 and a conversion element 92. The conversion element 92 is configured to convert the horizontal displacement of the conversion element 92 into the vertical displacement of the lower feeder assembly 22. The chassis 93 of the lower feeder assembly 22 is fixedly connected to the sliding element 94 so that the lower feeder assembly 22 moves as the conversion element 92 is horizontally displaced. This provides a stable and constant movement of the relatively heavy lower feeder assembly 22.

[0056] The feeder shifting mechanism 86 may include an actuator 90 in the form of at least one horizontal screw and a wedge-shaped transition element 92. Preferably, there are two feeder shifting mechanisms 86 along the longitudinal length of the lower feeder assembly 22.

[0057] Thus, the chassis 93 of the lower feeder assembly 22 may include a first wedge-shaped element 92, and the lower feeder assembly may include a second wedge-shaped element 94. The wedge-shaped elements are provided with a sliding contact surface.

[0058] In an alternative embodiment (not shown), the feeder shifting mechanism 86 may include a pair of vertical screws or an eccentric drive shaft.

[0059] The feeder module 12 further includes a feed roller assembly 34. The feed roller assembly 34 is located on the downstream side of the measuring instrument 32 and is configured to grab each sheet 2 and pull the sheet 2 out of the loading surface 24. The feed roller assembly 34 includes an upper feed roller 35a and a lower feed roller 35b.

[0060] The lower feed roller 35 b may be fixedly attached to the lower feeder assembly 22 and configured to shift in unison with the loading surface 24 .

[0061] Alternatively, the lower feed roller 35b can be mounted to a feed roller shifting mechanism 87. The feed roller shifting mechanism 87 is separate from the lower feeder assembly 22. The feed roller shifting mechanism 87 can be similar to the feeder shifting mechanism 86.

[0062] In one embodiment, the feed roller shifting mechanism 87 may include a first shifting device 87a configured to provide a first vertical displacement. The first vertical displacement may be between 0-30 mm. The first shifting device 87a may be similar to the feeder shifting mechanism 86. A second feed roller shifting device 87b is provided, which is configured to provide a larger displacement than the first shifting device 87a. The second feed roller shifting device 87b enables faster displacement of the lower feed roller 35b. The second shifting device 87b may be deployed in the event of a paper jam or maintenance. The second shifting device 87b may include at least one or preferably a plurality of hydraulic cylinders.

[0063] like Figure 2a As shown, the first printing unit 15 after the feeder module 12 may include a flexographic printing assembly configured to print on the lower side of the sheet 2. The first printing unit 15 may therefore include an anvil 100 arranged vertically above the printing cylinder 102. The anvil 100 may be fixedly mounted in the chassis of the printing unit 15. In another (not shown) embodiment, the first printing unit 15 after the feeder module 12 may include a flexographic printing assembly configured to print on the upper side of the sheet 2. The first printing unit 15 may therefore include an anvil arranged vertically below the printing cylinder. The printing cylinder may be fixedly mounted in the chassis of the printing unit 15.

[0064] The conveying unit 110 is located between the feed roller assembly 35 and the first printing unit 15. The conveying unit 110 includes a driving element 112 (e.g., a roller or a conveyor belt) configured to drive the sheet 2 forward along the transport direction T. The driving element 112 is preferably located in a suction box 114, which is provided with suction openings around the driving element 112. The suction holes are configured to allow the sheet to adhere to the driving element 112. A vacuum suction pump is connected to the suction box. When the driving element 112 contacts the sheet 2, the conveying path P in the conveying unit 110 is limited by an upper boundary formed by the surface of the driving element 112.

[0065] The conveying path P of the sheet 2 is defined by the gap provided by the measuring instrument 32 , the gap between the upper feed roller 35 a and the lower feed roller 35 , the conveying surface in the conveying unit 110 , and the gap between the printing cylinder 102 and the anvil 100 .

[0066] While the sheet 2 is conveyed along the conveying path P, the horizontal position of the upper surface of the sheet is defined by the distal vertical end 33 of the measuring instrument 32 , the upper feed roller 35 a , the conveying surface in the conveying unit 110 , and the upper cylinder in the flexographic printing unit 15 .

[0067] By keeping this upper boundary of the transport path P horizontal, damage to the sheet 2 can be avoided. According to the present invention, the upper feed roller 35a is kept in a position horizontally aligned with the transport surface in the transport unit 110. The movable loading surface 24 and the lower feed roller 35b allow adjustment for different sheet thicknesses w1 while keeping the upper boundary of the transport path P constant. The sheet thickness w1 is the height of the sheet in the vertical direction V.

[0068] When the thickness w1 of the sheet material 2 varies between different production batches, the displacement provided by the motor 88 changes the vertical position of the loading surface 24 .

[0069] The feeder module 12 may further include a control unit 13 configured to determine a required vertical displacement of the loading surface 24. Optionally, the control unit 13 may also be configured to determine a required vertical displacement of the lower feed roller 35b. The displacement may correspond to a difference in sheet thickness w1 of the sheets in the first production batch and the sheets in the second production batch.

Claims

1. A feeder module for a conversion machine, the feeder module comprising: a lower feeder assembly (22) comprising a loading surface (24) configured to receive a stack (S) of sheets (2) and a discharge conveyor (25) configured to discharge the sheets in a transport direction (T) through the converter, - an upper feeder assembly (20) comprising a measuring instrument (32), wherein the distance (d1) between a vertical distal end (33) of the measuring instrument and the loading surface defines a gap through which the lowermost sheet in the stack can pass, - A feed roller assembly (34) comprising an upper feed roller (35a) and a lower feed roller (35b), wherein the feed roller assembly is located downstream of the measuring instrument, characterized in that the lower feeder assembly (22) comprises a feeder shifting mechanism (86) configured to shift the loading surface in a vertical direction, and wherein the feed roller assembly (34) comprises a feed roller shifting mechanism (87) configured to shift the lower feed roller (35b) in a vertical direction.

2. The feeder module according to claim 1, wherein the upper feeder assembly (20) and the upper feed roller (35a) are fixedly arranged.

3. Feeder module according to any of the preceding claims, wherein the lower feed roller (35b) and the loading surface (24) are mounted in a common chassis.

4. Feeder module according to any one of claims 1-3, wherein the lower feed roller (35b) and the loading surface (24) are mounted in different chassis.

5. A feeder module according to claim 1 or 2, wherein the feed roller shifting mechanism (87) includes a first shifting device (87a) and a second shifting device (87b), and wherein the first shifting device is configured to shift the lower feed roller (35b) to a smaller distance than the second shifting device.

6. The feeder module of claim 1, wherein the feeder shifting mechanism (86) comprises a motor, an actuator, and a conversion element configured to convert horizontal displacement of the lower feeder assembly into vertical displacement.

7. Feeder module according to the preceding claim, wherein the actuator is a drive screw and the transition element is a wedge-shaped transition element.

8. A conversion machine comprising a feeder module according to any one of the preceding claims, wherein a conveying unit (110) is located downstream of the feed roller assembly (34), and wherein the conveying unit includes a drive element (112), the drive element having a contact surface configured to contact the sheet (2) and a vacuum hole configured to apply suction to the upper side of the sheet, wherein an upper feed roller is aligned with the conveying element in the conveying unit.

9. A printing machine according to the preceding claim, wherein the converter comprises a control unit (13) configured to determine a required displacement of the loading surface (24) and to actuate the feeder shifting mechanism (86) and the feed roller shifting mechanism to achieve the required displacement.

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