Field of the invention

The present invention relates to a converting machine for producing folding boxes or flat-packed boxes. In particular, it relates to a separator device for a converting machine.

Background

Converting machines are used in the production of paperboard and cardboard boxes, such as folding boxes. These machines comprise a plurality of workstations which may print, cut, crease, fold, count and stack blanks. The blank is initially placed in a feeder module and is conveyed through the different workstations.

The converting machines need to be adapted to different format of boxes, and this often leads to adjusting the position of a conveyor belt system, or transportation lengths of a conveyor belt system.

Document EP1350617B1 discloses a separator module of a converting machine. The separator module separates a shingled stream of boxes into batches with a predefined quantity. The separator module comprises a separator head which moves up and down in the vertical direction. The separator head is provided with a thrust plate (also referred to as a “stop plate”), and an upper evacuation conveyor belt. The evacuation conveyor belt is connected to the separator head and can be accelerated in order to increase the transportation speed of the separated batch. The evacuation conveyor belt abuts against a plurality of idle rollers which enable a free acceleration of the boxes.

Summary

In view of the prior art, it is an object of the present invention to provide a separator device with an improved precision and alignment during the transportation of the separated boxes. This object is solved by a separator device according to claim 1.

According to a first aspect of the present invention, there is provided a separator device for a folder-gluer machine, the separator device being configured to divide a shingled stream of folding boxes into separate batches, the separator device comprising: a vertically movable separator head configured to move up and down in a vertical direction between a counting position in which the separator head is not in contact with the boxes and a separating position in which the separator head is in contact with the boxes, at least one upper evacuation conveyor belt in the form of an endless belt, the upper evacuation conveyor belt having a contact portion for contacting an upper surface of the boxes when the separator head is in the separating position, and wherein the upper evacuation conveyor belt is configured to be driven at an evacuation speed when contacting the folding boxes, wherein the separator device further comprises a lower conveyor system having a first conveyor belt and a second conveyor belt arranged one after the other in a direction of transportation of the boxes, and wherein the first conveyor belt is configured to be operated at a first speed and the second conveyor belt is configured to be operated at a second speed when the separator device is in the counting position, and wherein the second conveyor belt is configured to be accelerated to a third speed when the separator head is in the separating position, and wherein the boxes are pinched between and transported by the upper evacuation conveyor belt and the lower second conveyor belt in unison.

The third speed is preferably equal to the evacuation speed of the upper evacuation conveyor belt.

The first conveyor belt can be referred to as the inlet conveyor belt and the second conveyor belt can be referred to as an evacuation conveyor belt. The separating position can also be referred to as an evacuating position.

In an embodiment, the first speed and the second speed are equal.

In an embodiment, the first and second conveyor belts of the lower conveyor system each have a modifiable contact length, and a transition point between the first conveyor belt and the second conveyor belt is displaceable in the direction of transportation. The of the sum of the contact lengths of the first and second conveyor belts is preferably constant.

The transition point between the first and second lower conveyor belts may be located upstream of the separator head in the direction of transportation.

In an embodiment the separator device further comprises a control system comprising a control unit and a memory. The memory comprises a program enabling the control unit to calculate a theoretical longitudinal position of the separator head and a theoretical longitudinal position of the transition point between the first and second lower conveyors.

In an embodiment the memory comprises instructions of the number of boxes to be included in each batch, and wherein the separator device further comprising a detection device configured to detect the passage of the front edges of the boxes and send information to the control system to initiate the descent of the separator head.

In an embodiment, the contact lengths of each respective conveyor belt is supported by a support structure comprising a plurality of rollers attached to roller frames, the roller frames being interconnected to each other by a connection mechanism to form a line. At least one distal roller frame is stationary and the remaining roller frames are movable in the direction of transportation. A displacement mechanism is connected to a movable distal roller frame of each support structure and is configured to displace the movable roller frames at a displacement distance in the direction of conveyance, whereby each support structure is extendable and retractable in the direction of transportation.

In an embodiment, the connection mechanism is configured to provide an equal displacement distance between each roller frame. Preferably, all rollers are in contact with the conveyor belts.

In an embodiment, the connection mechanism comprises a plurality of pivotable connection links.

The pivotable connection links may comprise a first linear connection element and a second linear connection element, and wherein the connection elements form a cross, the first and second linear connection elements having their central pivot point in the center of the cross, and wherein a connection to each roller frame is provided in the central pivot point.

In an embodiment the conveyor system further comprises a connection frame attached to the movable roller frame of the first conveyor belt and the movable roller frame of the second conveyor belt, and wherein the connection frame is connected to the displacement mechanism and configured to perform a reciprocating movement in the direction of transportation.

In an embodiment, the connection frame is further attached to a compensation roller of the first conveyor belt and a compensation roller of the second conveyor belt, whereby a displacement of the connection frame both modifies the contact lengths and the return lengths of the first and second conveyor belts.

Brief description of the drawings

The invention will now be described with reference to the appended drawings, in which like features are denoted with the same reference numbers and in which:

Figure 1a is a schematic diagram of a folder gluer converting machine,

Figure 1b is a top view of a blank to be placed in a feeder of the converting machine in figure 1a,

Figure 1c is a top view of a folding box produced in the converting machine of figure 1a;

Figure 2 is a schematic cross-sectional view of a transfer module of a converting machine as known in the prior art,

Figure 3 is schematic longitudinal cross-sectional view of a counterseparator module according to an embodiment of the present invention;

Figure 4 is a cross-sectional view of a conveyor system according to an embodiment of the present invention;

Figure 5 is a schematic perspective view of a displacement mechanism of the conveyor system of figure 4; Figures 6a and 6b are schematic cross-sectional views of a support mechanism according to an embodiment of the present invention;

Figure 6c is a schematic cross-sectional view of support mechanism according to another embodiment of the present invention;

Figure 7 is a schematic perspective view showing a connection between a support mechanism and a displacement mechanism;

Figures 8a and 8b are schematic perspective views of a conveyor system provided with two conveyor belts according to another embodiment of the present invention;

Figures 9a and 9b are cross-sectional views of the conveyor system which illustrate its maximum extension and retraction;

Figure 10 is a detailed schematic perspective view of a displacement mechanism; and

Figure 11 is a schematic perspective view of a conveyor system mounted onto a frame of a work module.

Detailed description

Referring to the figures and in particular to figures 1a and 1b which illustrate a converting machine in the form of a folder-gluer machine 1 and a blank 2’ to be processed produced therein. The folder-gluer machine 1 is configured to receive blanks 2’ that are provided with a peripheral edge 4 defining the shape of flaps 6 and is further provided with crease-lines 8, which enable the folding of the blank 2 along pre-defined lines. At the end of the converting machine 1 , the blanks 2 have been transformed into of folding boxes 2.

The present folder-gluer machine 1 comprises a series of different workstations in the form of modules. The modules include, from an inlet to an outlet: a feeder module 10, a fold pre-breaking module 12, a gluing module 14 and a folding module 16. After the folding and gluing modules, a conditioning section 20 can be provided in order to count and separate a shingled stream of folding boxes 2 into separate batches and to arrange them together in banded stacks. The conditioning section 20 of the folder gluer 1 may comprise a counter and separator module 22, optionally a shingle inverter 24, a transfer module 26 arranged after the shingle inverter 24, a stacker module 28 configured to arrange the folding boxes in stacks, and a banding module 29.

Several types of modules sometimes need to have their conveyance adapted to the format of the boxes 2 to be produced. Such examples include for example a transfer module 26 as illustrated in figure 2, a counter-separator module 22 as illustrated in figure 3 and an alignment module as described in document GB2182645.

As best seen in figures 1a, 2 and 3, the blanks 2 are transported through the different work modules in a direction of transportation D. The transportation of the blank 2 is partially effectuated by a conveyor system 30 comprising at least one conveyor belt 32. As best seen in figure 2, the conveyor belt 32 is in the form of an endless belt and is contacting the blanks 2 over a contact length Lc and is provided with a return path Pr of a length Lr, over which the conveyor belt 32 is not in contact with the blanks 2.

The inventors have found that work modules of a converting machine 1 can be provided with a conveyor system 30 with a variable contact length Lc of at least one conveyor belt 32. Such a variation in contact length Lc may have different advantageous technical effects and applications in terms of variable positions, distances, and transportation speeds.

As illustrated in figure 2, it can for instance be desirable to change the longitudinal position of an inlet end 34 or an outlet end 36 of a conveyor belt 32. In such a way, the longitudinal position of a transition point between two work modules can be modified. The transfer module 26 in figure 2 may be located upstream of a stacker module 28. The position of an outlet end 36 of the conveyor belt 32 can be set such that the rear edge 5b of a folding box 2 is positioned correctly in the stacker module 28. As the dimensions of the boxes 2 change between different work batches, it is advantageous to change the longitudinal position of the outlet end 36 of the conveyor belt 32.

As illustrated in figure 3, the present invention may also be used in order to achieve a conveyor system 30 having a fixed total length L_tot distributed over a plurality of transportation segments S1 , S2 with variable longitudinal contact lengths Lea, Lcb in the direction of transportation D. Such a conveyor system 30 may have a first conveyor belt 32a and a second conveyor belt 32b arranged one after the other in the direction of transportation D. The contact lengths Lea, Lcb of each respective conveyor belt 32a, 32b can be changed, while the total contact length L_tot of the conveyor system 30 remains unchanged. This can be advantageous in applications where the first conveyor belt 32a and the second conveyor belt 32b are driven differently, such as at different speeds V1 , V2

A possible application for this configuration is a conveyor system 30 for a separator module 22, where a batch of boxes 2 is separated and spaced apart from an upstream shingled stream of boxes 2. This is preferably done by a separator head 94 which momentarily stops an upstream-located shingled stream of boxes while accelerating the batch to be separated at an increased speed in the direction of transportation D.

As illustrated in figures 4 and 5, the conveyor system 30 according to the present invention comprises at least one conveyor belt 32, a support structure 38 and a displacement mechanism 40. The support structure 38 is configured to support the conveyor belt 32 over at least a portion of the contact length Lc from an inlet roller 34’ to an outlet roller 36’.

The trajectory of the return path Pr is supported by a plurality of guide rollers 42, a compensation roller 44 and drive sprocket 46. The compensation roller 44 is configured to change the trajectory of the conveyor belt 32 in the return path. The compensation roller 44 thus accommodates for changes in the contact length Lc by modifying the return length Lr of the conveyor belt 32 in the return path Pr.

As best seen in figures 5 and 6, the compensation roller 44 can be connected to a displacement mechanism 40 configured to change the location of the compensation roller 44 such that the return length Lr is changed. As the compensation roller 44 moves, the return length Lr of the conveyor belt 32 in the return path Pr is modified.

The drive sprocket 46 is connected to a motor (not illustrated) and is configured to drive the conveyor belt 32 in motion. The conveyor belt 32 may comprise engagement means, such as a dented surface which engages with the drive sprocket 46. As best seen in figures 6a, 6b and 7, the support structure 38 comprises a plurality of support rollers 52 connected to roller frames 54 and a connection mechanism 62 located in-between the roller frames 54. Each roller frame 54 preferably further comprises a slider 57a connected to a guide rail 57b, which is connected to a longitudinal frame member 60.

The contact length Lc of the conveyor belt 32 is thus supported by support rollers 52 arranged in a line and extending in the direction of transportation D. Over the contact length Lc, a first distal roller 34’ may be configured as the inlet roller 34’ and a second distal roller 36’ may be configured as the outlet roller 36’. Each support roller 52 is rotatably attached to a roller frame 54 by a pin 58. The support rollers 52 are preferably idle.

The conveyor system 30 may have one of the inlet roller 34’ and outlet roller 36’ stationary arranged, while the other roller 34’, 36’ is movable in the direction of transportation D. The roller frame 54 of the stationary arranged roller 34’, 36’ can be fixedly connected to the longitudinal frame member 60 of the work module. Alternatively, and as illustrated in figures 4 and 5, a distal central pivot 66 of the connection mechanism 62 is stationary while the outlet roller 36’ is displaceable in the direction of transportation D.

The sliders 57a of the roller frames 54 are slidably mounted onto the guide rail 57b. The guide rail 57b is fixedly mounted to the longitudinal frame member 60. The guide rail 57b restricts the movement of the roller frames 54 to the direction of transportation D.

The roller frames 54 are connected to each other in a line by the connection mechanism 62. The connection mechanism 62 is extendable and retractable in the direction of conveyance D such that a distance d1 between the support rollers 52 can be changed.

The connection mechanism 62 comprises a plurality of pivotable connection links 64. A pivotable connection link 64 is arranged between each of the roller frames 54. The connection mechanism 62 is configured such that a change in contact length ALc of the conveyor belt 32 is distributed over the plurality of pivotable connection links 64 in an equidistant displacement. The pivotable connection links 64 are thus configured to impart an equidistant displacement Ad between the roller frames 54. This means that when one of the roller frames 54 is displaced at a distance Ad, the remaining roller frames 54 are displaced at the same distance Ad.

The equidistant displacement may be calculated as:

Ad = ALc /N where:

Ad: displacement distance between rollers

ALc: change in contact length of conveyor belt

N: number of pivotable connection links

In order to restrict the displacement to be equidistant and to maintain an equal distance d1 between the rollers 56, the pivotable connection link 64 comprises a central pivot 66 connected to each roller frames 54, an upper pivot 68 and a lower pivot 70. The pivotable connection links 64 can be provided by two linear elements 64a, 64b.

In a preferred embodiment, the pivotable connection link 64 is symmetrical about a horizontal axis H extending through the central pivot 66. The horizontal axis H is coinciding with the longitudinal extension L of the support structure 38.

In this configuration, the pivotable connection links 64 form a plurality of “X-shapes” where the central pivot 66 is connected to each roller frame 54. By connecting the roller frames 54 to the central pivot 66, the horizontal position of the central pivot 66 is kept constant. However, a distance hi between the central pivot 66 and the upper pivot is variable. As best seen in figures 6a and 6b, the upper pivots 68 and the lower pivots 70 move in the vertical direction V when the support structure 38 is extended or retracted in the direction of transportation D. The X-shape also ensures that a resulting force Fr from the actuator is linear in the connection to the roller frames 54.

The pivotable connection links 64 can be provided by two linear elements 64a, 64b, each provided with a first convex shape 65a and a second with a convex shape 65b. The convex shape allows the strain to be better distributed in the connection links 64. Alternatively, as illustrated in figure 7, the pivotable connection links 64 may be linear elements with a uniform width and thickness. As illustrated in figure 7, the displacement mechanism 40 is connected to the connection mechanism 62. The displacement mechanism 40 may comprise a piston actuator 41 which can be directly connected to a movable roller frame 54 of the movable roller 34’ via an actuator rod 43. Alternatively, the piston actuator 41 can be connected to the movable roller frame 54 via a central pivot 66. The movable roller 34’ can be moved in the direction of transportation D in response to a change in the stroke length of the actuator rod 43.

In another embodiment, and as illustrated in figure 5, the displacement mechanism 40 may comprise a drive mechanism 72 and a connection frame 76. The connection frame 76 is connected to the movable distal roller 36’ via its roller frame 54. The drive mechanism 72 is configured to displace the connection frame 76 in the direction of transportation D. The drive mechanism 72 may comprise a displacement conveyor 78 attached to the connection frame 76 and a motor configured to move the displacement conveyor 78. Alternatively, the drive mechanism 72 may comprise a piston.

The connection frame 76 may also be connected to a compensation roller 44 and configured to provide an equal displacement of the movable distal roller 36’ and the compensation roller 44. In such a way, the absolute amount of displacement in the contact length Lc and the return length Lr is equal. If the contact length Lc increases with a length ALc, the return length Lr decreases with a length ALc, and vice versa.

Referring to back to figure 3, in which the conveyor system 30 has a first conveyor belt 32a and a second conveyor belt 32b arranged one after the other in the direction of transportation D. In this embodiment, each conveyor belt 32a, 32b is contacting a separate support structure 38.

As illustrated in figures 8a, 8b, 10 and 11 , a displacement mechanism 40 for such a conveyor system 30 may comprise an elongated frame member 76 connected to the outlet roller 36’ of the first conveyor belt 32a and the adjacent inlet roller 34’ of the second conveyor belt 32b. The elongated frame member 76 is movable in a reciprocating manner in the direction of transportation D. The direction of transportation D is coinciding with the longitudinal extension of the first conveyor belt 32a and second conveyor belt 32b. The adjacent rollers 34’, 36’ are thus fixedly mounted to the elongated frame member 76. This ensures that the distance Dp between the rollers 34 , 36 in the transition point T between the rollers 34 , 36 is unchanged. Moreover, this also results in that an increase in the contact length ALc of one conveyor belt 32a, 32b imparts a similar reduction of contact length ALc to the other conveyor belt 32a, 32b.

This is further illustrated in figures 9a and 9b, where figure 9a shows a configuration where the contact length Lea of the first conveyor belt 32a is in its most extended position. Figure 9b shows the configuration where the contact length Lcb of the second conveyor belt 32b is in its most extended position.

Preferably, and as best seen in figure 10, the frame member 76 is also connected to a first compensation roller 44a of the first conveyor belt 32a and to a second compensation roller 44b of the second conveyor belt 32a. In such a way, an equal displacement of the movable end rollers 34’, 36’ and the compensations rollers 44a, 44b is provided in response to a displacement of the elongated frame member 76 in the direction of transportation D..

As illustrated in figure 11 , the conveyor system 30 can be mounted onto a frame 31 of a work module. The work module may comprise several conveyor systems 30 mounted in parallel in the direction of transportation D.

The conveyor system 30 illustrated in figures 3, 8b, 8b and 11 is suitable for a separator module 22. The separator module 22 is configured to separate a shingled stream of boxes 2 into separate batches and to further convey them to a banding module 29, which applies retaining bands to assemble the boxes 2 in bundles.

As best seen in figure 3, the separator module 22 comprises an inlet section 91 , and a separator device 22’. The separator device 22’ comprises a vertically movable separation head 94, and a lower conveyor system 30. The separator module 22 may also further comprise a counting device 92, configured to count the boxes 2.

The separation head 94 is configured to move up and down in the vertical direction V between a counting position A and a separating position B. A batch is separated from an upstream shingled stream of boxes 2 when the separation head 94 descends from the counting position A into the separating position B. The separating position B may also be referred to as an evacuation position. The separation head 94 is provided with a thrust plate 96 (also referred to as stop plate”) and an evacuation conveyor 98. The evacuation conveyor 98 comprises at least one upper evacuation conveyor belt 99. Preferably, the evacuation conveyor 98 comprises two parallel upper evacuation conveyor belts 99. This allows the evacuation conveyor 98 to transport the boxes 2 while preventing rotation of the boxes 2.

The thrust plate 96 is configured to abut against the front leading edges 5a of the upstream shingled stream of boxes 2 such that they are momentarily stopped. A longitudinal separation point Ps can be defined by the position of the thrust plate 96. While the upstream-located boxes 2 are stopped, the evacuation conveyor belts 99 are moved at a speed V3. Preferably, the speed of the evacuation belt 99 changes from zero to V3.

The counting device 92 is configured to count the number of boxes 2 passing by the counting device 92. The counting device 92 may comprise a photoelectric cell, which optically detects the front leading edge 5a of the boxes 2. Alternatively, a mechanical counting device 92 may be used. For instance, a counting wheel can be in contact with the overlapping shingled stream of boxes 2 and can be configured to count in response to a registered up and down movement of the counting wheel.

When a desired number of boxes 2 has passed the counting device 92, the separation head 94 is moved downwardly into the separating position B to stop the remaining shingled stream of boxes 2. The separated batch can then be further conveyed to towards the banding module 29.

To further space the separated batch apart from the upstream shingled stream of boxes 2, the transportation speed of the separated batch may advantageously be increased downstream of the separation point Ps. In order to provide an increased transportation speed, the batch of boxes is accelerated after the location of the thrust plate 96.

In order to provide a speed difference, the lower conveyor system 30 is provided with a first conveyor belt 32a and a second conveyor belt 32b as illustrated in figures 3, 8a, 8b, 9a and 9b and as previously described. The first conveyor belt 32a can be referred to as an inlet conveyor belt 32a and the second conveyor belt 32b can be referred to as a lower evacuation conveyor belt 32b.

The first conveyor belt 32a is driven at a speed V1. The second conveyor belt 32b is configured to be accelerated between a second speed V2 and a third speed V3. The second speed V2 may be equal to the first speed V1 of the first conveyor belt 32a. The third speed V3 is higher than the first speed V1. The third speed V3 is also higher than the second speed V2.

The descent of thrust plate 96 is preferably located over the second conveyor belt 32b. Alternatively, the thrust plate 96 can be located in the transition point T between the first conveyor belt 32a and the second conveyor belt 32b.

When the separator head 94 is in the counting position A, the second conveyor belt 32b of the lower conveyor may be driven at the same speed V1 as the first conveyor belt 32a of the lower conveyor system 30.

The upper evacuation belt 99 and the lower evacuation belt 32b are moved at the same speed V3 when the separator head is in the separating position B. Both the upper evacuation belt 99 and the lower evacuation belt 32b are accelerated once the separator head 94 reaches the separating position B.

The conveyor system 30 may be further connected to a control system 100 comprising a control unit 102 and a memory 104. The control system 100 is configured to determine the longitudinal position (in the direction of transportation D) of the separator head 94 in relation to the number of boxes 2 to be included in each bundle and the format of the boxes 2. The longer the boxes 2 are in the direction of transportation D and/or the more boxes 2 to be included in each bundle, the longer accumulation distance L_coll (see fig. 3) on the second conveyor belt 32b is needed.

The control system 100 may be configured to determine a theoretical longitudinal separation point Ps of the separator head 94 based on box dimensions entered into the control system 100. However, there may be some variations in the conveyance of the boxes 2. Therefore, the separation head 94 may be further configured to adapt its longitudinal position in response to information from the counting device 92. The counting device 92 indicates the number of boxes 2 that has passed downstream of the separation point Ps. At the passage of the last box 2 in a predefined number of the bundle, the counting device may also provide a time of passage of the front edge 5a of the last boxe 2 which indicates a register position to the separator head 94. In such a way, the separator head 94 can descend with precision and keep a constant and predetermined number of boxes 2 in each bundle.

The transition point T between the first conveyor belt 32a and the second conveyor belt 32b can be determined from the position of the separator head 94. For instance, the transition point T may be located at a predetermined distance ds from the separator head. The transition point T between the first and the second conveyor belts 32a, 32b may dynamically follow the longitudinal position of the separator head 94 for each batch of boxes 2.

A first mechanism enabling such an adjustment is a top frame portion 95 of the counter-separator module to which the separator head 94 is movably mounted. The top frame portion 95 may comprise a slide rail 93 (see fig. 3) to which the separator head is slidably mounted. In such a way, the separator head 94 can be moved and positioned in a desired location in the direction of transportation D.

The boxes 2 are pinched in between the upper evacuation conveyor belts 99 and the lower evacuation conveyor 32b. This provides an improved stability of the shingled stream of boxes 2 and smaller formats of boxes can be handled with increased stability as they are supported on the top and the bottom sides.

The conveyor system 30’ may comprise a first lower conveyor system 30a and a second lower conveyor system 30b arranged parallel in relation to each other. Hence, both conveyor systems comprise a first conveyor belt 32a and the second conveyor belt 32b. In this embodiment, the upper evacuation conveyor also preferably comprises a first and a second evacuation conveyor belt 99. In such a way, the boxes 2 are pinched between four conveyor belts 99.