Device for stacking sheets, especially corrugated board sheets, and method

Abstract

The stacking device includes a stacking platform, and a conveyor with an inlet and an outlet. The inlet is adapted to receive shingled sheets and the outlet is positioned to discharge the sheets on a stack of sheets being formed on the stacking platform. Along the conveyor, upstream of the outlet of the conveyor, there are arranged a first aligning member and a second aligning member, opposite to each other and adapted to cooperate with longitudinal edges of the shingled sheets which advance along the conveyor, to align them with respect to the stack being formed on the stacking platform.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of machines for manufacturing and handling sheets, in particular corrugated board sheets. Embodiments described herein relate to stacking devices and methods for stacking sheets, for example and in particular corrugated board sheets.BACKGROUND ART

[0002] The lines for the production of corrugated board sheets, for example creased corrugated board sheets for obtaining board boxes, comprise an area for forming a continuous corrugated board and an area for longitudinal slitting, scoring and cross cutting of a continuous web of corrugated board. This second area with a conveyor and a stacking platform, configured to receive several shingled, i.e., partially superimposed, sheets and discharge the sheets on the stacking platform where stacks or packs of sheets are formed, which are then packaged and shipped.

[0003] In particular, the present invention relates to improvements regarding end areas (also called “dry end”) of the production line, wherein the continuous web of corrugated board is converted into creased sheets, which are superimposed to form stacks or packs.

[0004] Conveyor and stacking systems of the prior art are described in JP2001106411, U.S. Pat. No. 3,667,751, DE19931742, U.S. Pat. No. 4,934,687.

[0005] The production rate of these lines is very high, and members are usually associated with the stacking platform, which form abutments for correctly positioning and superimposing with respect to each other in an orderly manner the single sheets coming from the conveyor. These members typically have a front abutment, against which the sheets discharged by the conveyor on the stacking platform are frontally stopped. In some cases, lateral abutments are also provided, which align the sheets with respect to each other along the lateral surfaces of the stack being formed. In some cases, the production line is without lateral abutments due to reasons space limitation or due to the shape of the brushes which are located at the end of the conveyor and which serve to brake and correctly direct the sheets on the stack being formed. The absence of lateral abutments involves the risk of an incorrect and disorderly superimposition of the sheets on the stack, which can result in packaging problems.

[0006] The present invention relates to a device which solves or reduces the problems of stacking devices of the prior art, especially with regard to the correct superimposition and the correct alignment in the transversal direction of sheets on the stacking platform.SUMMARY

[0007] According to a first aspect, disclosed herein is a stacking device comprising a stacking platform, and a conveyor having an inlet and an outlet. The inlet is adapted to receive shingled sheets and the outlet is positioned to discharge the sheets on a stack of sheets being formed on the stacking platform. Along the conveyor, upstream of the outlet of the conveyor, there are arranged a first aligning member and a second aligning member, opposite to each other and adapted to cooperate with longitudinal edges of the shingled sheets which advance along the conveyor, to align them with respect to the stack being formed on the stacking platform.

[0008] The alignment members engage the shingled, i.e., partially superimposed, sheets as the sheets advance along the conveyor, before the sheets reach the conveyor outlet and consequently before they reach a stack being formed on the stacking platform. This allows to obtain an orderly stack with sheets that are laterally aligned, without the need for providing aligning members in the volume in which the stack being formed is found, in which volume these members could interfere with the rollers, brushes or other devices arranged at the outlet of the conveyor and adapted to control the exit of the sheets from the conveyor.

[0009] The first aligning member and the second aligning member are supported on a transverse support, extending transversely to an advancement direction of the conveyor. This allows to obtain simple and non-cumbersome structure that also allows to adjust the mutual distance between the aligning members as a function of the width of the sheets to be handled, i.e., the size of the sheets in the orthogonal direction with respect to the advancement direction.

[0010] In order to register, i.e., to adjust the mutual spacing of the aligning members, in certain embodiments the first aligning member is supported by a first slide which can be adjusted in position along the transverse support, and the second aligning member is supported by a second slide which can be adjusted in position along the transverse support. Each of said first slide and second slide comprises an actuator configured to move the respective slide along the transverse support. This allows the mutual distance of the two aligning members to be adjusted by independent movements of the two aligning members in a direction orthogonal to the advancement direction of the sheets.

[0011] Further advantageous embodiments and optional features of the stacking device according to the present invention are defined in the dependent claims and will be described below with reference to the attached drawings, which show a non-limiting embodiment of a stacking device.

[0012] In certain embodiments, the aligning members may be shaped in a lead-in shape, to receive and center between them the sheets which advance along the conveyor.

[0013] In certain embodiments, each of said first aligning member and second aligning member is provided with a transverse movement to repeatedly urge the respective longitudinal edges of the shingled sheets as the sheets advance along the conveyor. This movement may be imparted by actuators which make the two aligning members carry out controlled and synchronous movements for mutual approaching and moving away movement. In certain embodiments, the aligning members may be provided, additionally or alternatively to the mutual approaching and moving away movement, with a vibration movement, imposed by a respective vibrator or vibration feeder.

[0014] Generally, these movements allow a more effective aligning of the sheets, which is particularly useful when the sheets are heavy and / or have a high degree of superimposition. The dynamic thrust effect of the aligning members on the longitudinal edges of the sheets improves the effectiveness of the aligning device.

[0015] Basically, the dynamic thrust effect of the aligning members may be obtained by providing each of said first aligning member and second aligning member of a respective actuator which imparts to the respective aligning member a repeating movement with at least one motion component orthogonal to the advancement direction of the conveyor and parallel to a support surface of the conveyor.

[0016] Basically, when the aligning members are carried by slides for adjusting the transversal position of the aligning members with respect to the conveyor, each of said first aligning member and second aligning member may comprise a respective actuator which moves the aligning member with respect to the respective slide with a repeating movement having at least one motion component orthogonal to the advancement direction of the conveyor and parallel to a support surface of the sheets on the conveyor.

[0017] In order to allow an easy adjustment of the transversal position of the aligning members, and to allow an easy removal of sheets which might remain stuck under the aligning members, in certain embodiments each of said first aligning member and second aligning member may include a respective actuator configured to lift and lower the alignment member relative to the conveyor.

[0018] In order to allow the aligning members to be positioned as close as possible to the conveyor, thereby avoiding the formation of gaps into which sheets to be aligned may become inadvertently lodged, in advantageous embodiments each of said first aligning member and second aligning member may comprise rolling bodies configured to rest on the conveyor or on a plane adjacent to the conveyor.

[0019] In certain embodiments, each of said first aligning member and second aligning member may comprise a plate approximately orthogonal to the conveyor, preferably provided with a lead-in edge facing towards the inlet of the conveyor.

[0020] According to a further aspect, disclosed herein is a method for forming stacks of superimposed sheets, comprising the following steps: supplying a flow of shingled sheets along the conveyor, from an inlet of the conveyor towards an outlet of the conveyor; discharging the sheets from the outlet of the conveyor on a stacking platform, gradually moving the stacking platform and the outlet of the conveyor away from each other; and mutually aligning the shingled sheets along the conveyor, upstream of the outlet of the conveyor.

[0021] The step for mutually aligning the shingled sheets may comprise the step for transversely pushing the shingled sheets simultaneously through a first aligning member and a second aligning member, opposite to each other.

[0022] Basically, each of said first aligning member and second aligning member may be provided with a reciprocal transversal movement which generates a dynamic thrust in a direction transversal to the longitudinal edges of the sheets which advance along the conveyor.

[0023] Further advantageous embodiments and optional features of the method according to the present invention are set forth in the dependent claims and will be described with reference to the attached drawings, which show a non-limiting example of a stacking device.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be clearer from the description and the attached drawings, which illustrate embodiments of the invention provided by way of non-limiting example. More particularly, in the drawings:

[0025] FIG. 1 is a schematic lateral view of a terminal part of a line for producing corrugated board sheets, comprising a stacking device with a conveyor and a stacking platform, according to an embodiment;

[0026] FIG. 2 is an isolated axonometric view of the device comprising the aligning members;

[0027] FIGS. 3 and 4 are enlargements of the aligning members of FIG. 2;

[0028] FIG. 5 is a section according to V-V, along a vertical plane, of the aligning device; and

[0029] FIGS. 6 and 7 are front views of the aligning members in two different positions.DETAILED DESCRIPTION

[0030] By way of summary, in order to alleviate or solve the problem of laterally aligning the sheets stacked on the stacking platform, a stacking device is provided which comprises, along the sheet supplying conveyor, a pair of opposite aligning members, which cooperate with the longitudinal edges of the sheets which advance, in a shingled configuration, along the conveyor. The aligning members act passively or actively on the sheets, to align them, so that their longitudinal edges are correctly positioned in the transversal direction, that is orthogonal to the advancement direction. In this manner, the sheets are stacked in an orderly and aligned manner on the stacking platform, without the need for aligning members downstream of the conveyor.

[0031] Referring now to the drawings, FIG. 1 schematically illustrates the final part of a line for producing corrugated board sheets, indicated in its entirety with 1. In this part of the line a stacking device 3 is provided, which basically forms the final part of the production line. In the illustrated embodiment, the stacking device 3 is a double stacking device, which comprises two conveyors and two stacking platforms, as better described below. In other embodiments, the stacking device 3 may be single and it may include a single conveyor. In yet further embodiments, the stacking device 3 may comprise three or more stacking platforms.

[0032] The two conveyors are indicated with 5A and 5B. The first conveyor 5A supplies corrugated board sheets FA towards a first stacking area 7A where a first stacking platform 9A is arranged. Similarly, the second conveyor 5B supplies corrugated board sheets FB towards a second stacking area 7B where a second stacking platform is arranged 9B. The second conveyor 5B extends above the first conveyor 5A to reach the second stacking platform 9B which is located aligned in the advancement direction of the sheets FA, FB, downstream of the first stacking platform 9A.

[0033] The first conveyor 5A comprises an inlet 10A and an outlet 12A. At the inlet 10A shingling members 11A are positioned, not described and per se known, which may for example comprise brushes, suctioning belts or other members which brake the sheets FA reaching to the conveyor 5A and cause the partial overlapping thereof to take a shingled condition. The sheets maintain the shingled arrangement up to the stacking platform 9A. The outlet 12A may be provided with output rollers, brushes or prongs, or other members for controlling the ejection movement of the sheets FA towards the stacking platform 9A.

[0034] Similarly, the second conveyor 5B comprises an inlet 10B and an outlet 12B. At the inlet 10B shingling members 11B are positioned, similar to the shingling members 11A, which brake the sheets FB reaching the second conveyor 5B and causes the partial overlapping thereof to take the shingled condition. The sheets FB maintain the shingled arrangement up to the stacking platform 9B. The outlet 12B may be provided with output rollers, brushes or prongs, or other members for controlling the ejection movement of the sheets FB towards the stacking platform 9B.

[0035] Each conveyor 5A, 5B may consist series of conveyor belts, as schematically shown in FIG. 1, which may advance at a speed that may be variable and different from each other, for example so as to generate a gap in the flow of shingled sheets, to allow the removal of a complete stack of sheets PA, PB from the stacking platform 9A, 9B and allow the start of the formation of a subsequent stack.

[0036] Along the path of each conveyor 5A, 5B a device for the lateral aligning the sheets FA, FB is arranged, which provides for correcting any skidding of the sheets FA, FB in the lateral direction, i.e., in a transverse direction with respect to the advancement direction of the sheets along the conveyors 5A, 5B. The overall advancement direction of the sheets FA, FB is generally and summarily indicated with F. The lateral aligning devices are indicated with 21A, 21B. The two devices 21A, 21B may be equal to each other. One of said aligning devices will be described below with reference to the following FIGS. 2 to 7 and indicated therein with 21.

[0037] The aligning device 21 comprises a first aligning member 23 and a second aligning member 25. The two aligning members 23, 25 may be symmetrical to each other and they are opposite with respect to each other.

[0038] The aligning members 23, 25 may be provided with various movements with respect to a stationary load-bearing structure, which also carries the respective conveyor 5A or 5B. Each aligning member 23, 25 is provided with a first adjustment movement in a direction orthogonal to the advancement direction F of the sheets FA, FB on the respective conveyor 5A, 5B. In FIGS. 2 to 7 this first movement is indicated with f23 for the aligning member 23 and with f25 for the aligning member 25. The adjustment movement according to f23 and f25 may be obtained by mounting each aligning member 23, 25 on a respective slide 33, 35, in turn supported on a transverse support, which extends transversely to the direction F. In the illustrated embodiment, the transverse support is indicated with 27 and consists of a transversal beam. Below, the transverse support will also be referred to as “beam” for the sake of brevity. Each slide 33, 35 is provided with a movement according to the longitudinal extension of the beam 27. In the illustrated embodiment, on the beam 27 there are integrally mounted guides 29 extending orthogonally to the direction F and parallel to the longitudinal extension of the beam 27. The latter is stationary to the load-bearing structure which supports the respective conveyor 5A or 5B.

[0039] A first slide 33 which carries the first aligning member 23 and a second slide 35 which carries the second aligning member 25 are engaged to the guides 29 by means of shoes 31.

[0040] The movement of the slides 33 and 35 according to the double arrow f23 and f25 may be controlled by a respective actuator 37 and 39, for example an electric motor, which rotates a pinion (FIG. 5 shows the pinion 40 of the actuator 37), meshing with a rack 41 that extends longitudinally along the beam 27 and is integrally joined therewith.

[0041] Each aligning member 23, 25 may comprise a plate 45, 47 with respective upstream and downstream edges (with respect to the advancement direction of the conveyor 5A, 5B) inclined with respect to the central portion of the plate 45, 47. Each plate 45, 47 is substantially orthogonal to the respective conveyor 5A, 5B and it may have an inclined upstream edge 45A, 47A and a bevelled downstream edge 45B, 47B. The inclined edges form a lead-in element for the sheets FA, FB which advance between the two aligning members 23, 25.

[0042] Each aligning member 23, 25 may be provided with a lifting and lowering movement with respect to the conveyor 5A, 5B. To this end, see FIG. 3, the first aligning member 23 is carried by the respective slide 33 by interposing a carriage 51 that is movable vertically according to a double arrow f51 with respect to the conveyor 5A / 5B and therefore with respect to the first slide 33. The carriage 51 may be connected to the first slide 33 through a vertical guide 52 integrally joined with the first slide 33 and through a shoe 54 integrally joined with the carriage 51, or vice versa. Similarly, see FIG. 4, the second aligning member 25 is carried by the respective slide 35 by interposing a carriage 53 that is movable vertically according to the double arrow f53 with respect to the conveyor 5A / 5B and therefore with respect to the second slide 35. The carriage 53 may be connected to the second slide 35 through a vertical guide 56 integrally joined with second slide 35 and through a shoe 58 integrally joined with the carriage 53, or vice versa.

[0043] The movement according to f51 of the carriage 51 may be controlled by an actuator 61, for example a cylinder-piston actuator. Similarly, the movement according to f51 of the carriage 53 may be controlled by an actuator 63, for example a cylinder-piston actuator. The lifting and lowering movement according to f51 may be useful during the step of transverse positioning of the aligning members 23, 25 (translation according to f23 and f25). The lifting movement in this case may also be used in case of jam-up, i.e., should the sheets be stuck along the conveyor, to facilitate the removal of sheets which may be stuck under the aligning members.

[0044] The plate 45 may be constrained to the carriage 51 through a further actuator, which imparts to the plate 45 a reciprocating motion having at least one motion component (indicated with f63) parallel to the plane defined by the conveyor 5A / 5B and orthogonal to the direction F. Similarly, the plate 47 may be constrained to the carriage 53 through a further carriage 67, which imparts to the plate 47 a reciprocating motion having at least one motion component (indicated with f67) parallel to the plane defined by the conveyor 5A / 5B and orthogonal to the direction F. The actuators which control the movement according to f63 and f67 may be cylinder-piston actuators, as shown by way of example in the drawing, or vibrators or vibrator feeder, or other actuators adapted to generate an alternating motion according to the direction f63 and f67, or at least with a component in such direction.

[0045] In advantageous embodiments, each carriage 51, 53 comprises respective rolling bodies 71 configured to rest on the conveyor 5A / 5B or on a plane adjacent to the conveyor 5A / 5B. In the illustrated embodiment, support planes 75 are provided at both sides of the conveyor 5A / 5B configured to rest thereon the respective carriage 51 or 53 when the carriage is positioned laterally outside the respective longitudinal edge of the conveyor belt which forms the conveyor 5A / 5B. The longitudinal edge of the conveyor belt is indicated with 77 in FIGS. 6 and 7. The rolling bodies 71 form means for supporting the carriages 51, 53. The use of rolling bodies, instead of shoes or other stationary means, for example, facilitates the resting of the carriages 51, 53 on the conveyor belt forming part of the conveyor 5A / 5B. In this manner, each carriage 51, 53 may rest on the conveyor with minimum friction. The distance between the aligning members 23, 25 and the upper surface of the conveyor 5A / 5B is therefore reduced to the minimum to prevent the sheets with smaller thickness from inadvertently passing under the aligning members.

[0046] The stacking device described above operates as described below with reference to the conveyor 5A, it being understood that the conveyor 5B may operate in an equivalent manner.

[0047] The sheets FA, which may be produced by transversely cutting a continuous corrugated board strip, are partially superimposed with respect to each other at the inlet 10A through shingling members 11A and advance in this condition up to the outlet 12A of the conveyor 5A / 5B. Here, the sheets are ejected and stacked on the stacking platform 9A, forming a stack PA. In order to allow the formation of the stack, the outlet 12A of the conveyor 5A and the stacking platform 9A have a relative movement in the vertical direction according to the double arrow f9. As known to those skilled in the art, the stacking platform 9A may move downwards during the formation of the stack Pa, while the conveyor 5A remains stationary. There cannot be ruled out the possibility of operating in the opposite manner, that is to hold the stacking platform 9A stationary, while the stack PA is formed by gradually lifting the outlet end 12A of the conveyor 5A. In both cases, the device 21A for lateral aligning of the sheets remains stationary with respect to the outlet 12A of the conveyor 5A.

[0048] Before starting the stacking operations, the aligning members 23, 25 are carried in the correct working position. This position is determined by the width of the sheets FA which advance on the conveyor 5A. The distance between the opposite surfaces of the plates 45, 47 is equal to the width of the sheets 5A, i.e., the distance between the longitudinal edges of each sheet 5A.

[0049] If, as shown in the exemplary embodiment, the aligning members 23, 25 have a reciprocating approaching and distancing movement (f63, f67), the minimum distance between the plates 45, 47 is set so as to be substantially equal to the width of the sheets FA.

[0050] The adjustment movement for setting the correct position of the aligning members 23, 25 is imparted by the actuators 37, 39 and is carried out by preferably holding the carriages 51, 53 raised with respect to the conveyor 5A, so that the positioning movement can be carried out without contact between the rolling bodies 71 and the underlying surfaces (conveyor 5A and support planes 73, 75). Once the slides 33, 35, the carriages 51, 53 and the plates 45, 47 have reached the correct position, the carriages 51, 53 can be lowered until the rolling bodies 71 rest on the conveyor 5A or on one or the other of the support planes 73, 75.

[0051] During stacking, the aligning members 23, 25 rest with the rolling bodies 71 on the upper surface of the conveyor 5A (or on one or on the other of the support planes 73, 75) and move cyclically and repeatedly according to f63 and f67 so as to repeatedly push with the plates 45, 47 against the edges of the sheets FA which pass between the aligning members. The frequency of the movement according to f63 and f67 may be set advantageously so that, at a given linear advancement speed of the sheets FA along the conveyor 5A, each sheet comes into simultaneous contact with the aligning members 23, 25 at least once. The cyclic, or repeated, and synchronised movement of the aligning members 23, 25 allows any lateral misalignments of the sheets FA to be corrected, so that each sheet FA arrives on the stacking platform 9A in the correct position, centred with respect to the stack 9A being formed.

[0052] The cyclic or repeated movement which brings the aligning members to cooperate with the longitudinal edges of the sheets FA (that is the edges parallel to the advancement direction F) dynamically facilitates the straightening and the correct orientation of the sheets FA. It cannot be ruled out that in some cases, for example with sheets that are small in size, the aligning effect can be obtained passively, that is holding the aligning members 23, 25 in a fixed position and using for the aligning the geometric shape for guiding the inlet edges 45A, 47A of the plates 45, 47.

Examples

Embodiment Construction

[0030]By way of summary, in order to alleviate or solve the problem of laterally aligning the sheets stacked on the stacking platform, a stacking device is provided which comprises, along the sheet supplying conveyor, a pair of opposite aligning members, which cooperate with the longitudinal edges of the sheets which advance, in a shingled configuration, along the conveyor. The aligning members act passively or actively on the sheets, to align them, so that their longitudinal edges are correctly positioned in the transversal direction, that is orthogonal to the advancement direction. In this manner, the sheets are stacked in an orderly and aligned manner on the stacking platform, without the need for aligning members downstream of the conveyor.

[0031]Referring now to the drawings, FIG. 1 schematically illustrates the final part of a line for producing corrugated board sheets, indicated in its entirety with 1. In this part of the line a stacking device 3 is provided, which basically f...

TECHNICAL FIELD

[0001] The present invention relates to the field of machines for manufacturing and handling sheets, in particular corrugated board sheets. Embodiments described herein relate to stacking devices and methods for stacking sheets, for example and in particular corrugated board sheets.BACKGROUND ART

[0002] The lines for the production of corrugated board sheets, for example creased corrugated board sheets for obtaining board boxes, comprise an area for forming a continuous corrugated board and an area for longitudinal slitting, scoring and cross cutting of a continuous web of corrugated board. This second area with a conveyor and a stacking platform, configured to receive several shingled, i.e., partially superimposed, sheets and discharge the sheets on the stacking platform where stacks or packs of sheets are formed, which are then packaged and shipped.

[0003] In particular, the present invention relates to improvements regarding end areas (also called “dry end”) of the production line, wherein the continuous web of corrugated board is converted into creased sheets, which are superimposed to form stacks or packs.

[0004] Conveyor and stacking systems of the prior art are described in JP2001106411, U.S. Pat. No. 3,667,751, DE19931742, U.S. Pat. No. 4,934,687.

[0005] The production rate of these lines is very high, and members are usually associated with the stacking platform, which form abutments for correctly positioning and superimposing with respect to each other in an orderly manner the single sheets coming from the conveyor. These members typically have a front abutment, against which the sheets discharged by the conveyor on the stacking platform are frontally stopped. In some cases, lateral abutments are also provided, which align the sheets with respect to each other along the lateral surfaces of the stack being formed. In some cases, the production line is without lateral abutments due to reasons space limitation or due to the shape of the brushes which are located at the end of the conveyor and which serve to brake and correctly direct the sheets on the stack being formed. The absence of lateral abutments involves the risk of an incorrect and disorderly superimposition of the sheets on the stack, which can result in packaging problems.

[0006] The present invention relates to a device which solves or reduces the problems of stacking devices of the prior art, especially with regard to the correct superimposition and the correct alignment in the transversal direction of sheets on the stacking platform.SUMMARY

[0007] According to a first aspect, disclosed herein is a stacking device comprising a stacking platform, and a conveyor having an inlet and an outlet. The inlet is adapted to receive shingled sheets and the outlet is positioned to discharge the sheets on a stack of sheets being formed on the stacking platform. Along the conveyor, upstream of the outlet of the conveyor, there are arranged a first aligning member and a second aligning member, opposite to each other and adapted to cooperate with longitudinal edges of the shingled sheets which advance along the conveyor, to align them with respect to the stack being formed on the stacking platform.

[0008] The alignment members engage the shingled, i.e., partially superimposed, sheets as the sheets advance along the conveyor, before the sheets reach the conveyor outlet and consequently before they reach a stack being formed on the stacking platform. This allows to obtain an orderly stack with sheets that are laterally aligned, without the need for providing aligning members in the volume in which the stack being formed is found, in which volume these members could interfere with the rollers, brushes or other devices arranged at the outlet of the conveyor and adapted to control the exit of the sheets from the conveyor.

[0009] The first aligning member and the second aligning member are supported on a transverse support, extending transversely to an advancement direction of the conveyor. This allows to obtain simple and non-cumbersome structure that also allows to adjust the mutual distance between the aligning members as a function of the width of the sheets to be handled, i.e., the size of the sheets in the orthogonal direction with respect to the advancement direction.

[0010] In order to register, i.e., to adjust the mutual spacing of the aligning members, in certain embodiments the first aligning member is supported by a first slide which can be adjusted in position along the transverse support, and the second aligning member is supported by a second slide which can be adjusted in position along the transverse support. Each of said first slide and second slide comprises an actuator configured to move the respective slide along the transverse support. This allows the mutual distance of the two aligning members to be adjusted by independent movements of the two aligning members in a direction orthogonal to the advancement direction of the sheets.

[0011] Further advantageous embodiments and optional features of the stacking device according to the present invention are defined in the dependent claims and will be described below with reference to the attached drawings, which show a non-limiting embodiment of a stacking device.

[0012] In certain embodiments, the aligning members may be shaped in a lead-in shape, to receive and center between them the sheets which advance along the conveyor.

[0013] In certain embodiments, each of said first aligning member and second aligning member is provided with a transverse movement to repeatedly urge the respective longitudinal edges of the shingled sheets as the sheets advance along the conveyor. This movement may be imparted by actuators which make the two aligning members carry out controlled and synchronous movements for mutual approaching and moving away movement. In certain embodiments, the aligning members may be provided, additionally or alternatively to the mutual approaching and moving away movement, with a vibration movement, imposed by a respective vibrator or vibration feeder.

[0014] Generally, these movements allow a more effective aligning of the sheets, which is particularly useful when the sheets are heavy and / or have a high degree of superimposition. The dynamic thrust effect of the aligning members on the longitudinal edges of the sheets improves the effectiveness of the aligning device.

[0015] Basically, the dynamic thrust effect of the aligning members may be obtained by providing each of said first aligning member and second aligning member of a respective actuator which imparts to the respective aligning member a repeating movement with at least one motion component orthogonal to the advancement direction of the conveyor and parallel to a support surface of the conveyor.

[0016] Basically, when the aligning members are carried by slides for adjusting the transversal position of the aligning members with respect to the conveyor, each of said first aligning member and second aligning member may comprise a respective actuator which moves the aligning member with respect to the respective slide with a repeating movement having at least one motion component orthogonal to the advancement direction of the conveyor and parallel to a support surface of the sheets on the conveyor.

[0017] In order to allow an easy adjustment of the transversal position of the aligning members, and to allow an easy removal of sheets which might remain stuck under the aligning members, in certain embodiments each of said first aligning member and second aligning member may include a respective actuator configured to lift and lower the alignment member relative to the conveyor.

[0018] In order to allow the aligning members to be positioned as close as possible to the conveyor, thereby avoiding the formation of gaps into which sheets to be aligned may become inadvertently lodged, in advantageous embodiments each of said first aligning member and second aligning member may comprise rolling bodies configured to rest on the conveyor or on a plane adjacent to the conveyor.

[0019] In certain embodiments, each of said first aligning member and second aligning member may comprise a plate approximately orthogonal to the conveyor, preferably provided with a lead-in edge facing towards the inlet of the conveyor.

[0020] According to a further aspect, disclosed herein is a method for forming stacks of superimposed sheets, comprising the following steps: supplying a flow of shingled sheets along the conveyor, from an inlet of the conveyor towards an outlet of the conveyor; discharging the sheets from the outlet of the conveyor on a stacking platform, gradually moving the stacking platform and the outlet of the conveyor away from each other; and mutually aligning the shingled sheets along the conveyor, upstream of the outlet of the conveyor.

[0021] The step for mutually aligning the shingled sheets may comprise the step for transversely pushing the shingled sheets simultaneously through a first aligning member and a second aligning member, opposite to each other.

[0022] Basically, each of said first aligning member and second aligning member may be provided with a reciprocal transversal movement which generates a dynamic thrust in a direction transversal to the longitudinal edges of the sheets which advance along the conveyor.

[0023] Further advantageous embodiments and optional features of the method according to the present invention are set forth in the dependent claims and will be described with reference to the attached drawings, which show a non-limiting example of a stacking device.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be clearer from the description and the attached drawings, which illustrate embodiments of the invention provided by way of non-limiting example. More particularly, in the drawings:

[0025] FIG. 1 is a schematic lateral view of a terminal part of a line for producing corrugated board sheets, comprising a stacking device with a conveyor and a stacking platform, according to an embodiment;

[0026] FIG. 2 is an isolated axonometric view of the device comprising the aligning members;

[0027] FIGS. 3 and 4 are enlargements of the aligning members of FIG. 2;

[0028] FIG. 5 is a section according to V-V, along a vertical plane, of the aligning device; and

[0029] FIGS. 6 and 7 are front views of the aligning members in two different positions.DETAILED DESCRIPTION

[0030] By way of summary, in order to alleviate or solve the problem of laterally aligning the sheets stacked on the stacking platform, a stacking device is provided which comprises, along the sheet supplying conveyor, a pair of opposite aligning members, which cooperate with the longitudinal edges of the sheets which advance, in a shingled configuration, along the conveyor. The aligning members act passively or actively on the sheets, to align them, so that their longitudinal edges are correctly positioned in the transversal direction, that is orthogonal to the advancement direction. In this manner, the sheets are stacked in an orderly and aligned manner on the stacking platform, without the need for aligning members downstream of the conveyor.

[0031] Referring now to the drawings, FIG. 1 schematically illustrates the final part of a line for producing corrugated board sheets, indicated in its entirety with 1. In this part of the line a stacking device 3 is provided, which basically forms the final part of the production line. In the illustrated embodiment, the stacking device 3 is a double stacking device, which comprises two conveyors and two stacking platforms, as better described below. In other embodiments, the stacking device 3 may be single and it may include a single conveyor. In yet further embodiments, the stacking device 3 may comprise three or more stacking platforms.

[0032] The two conveyors are indicated with 5A and 5B. The first conveyor 5A supplies corrugated board sheets FA towards a first stacking area 7A where a first stacking platform 9A is arranged. Similarly, the second conveyor 5B supplies corrugated board sheets FB towards a second stacking area 7B where a second stacking platform is arranged 9B. The second conveyor 5B extends above the first conveyor 5A to reach the second stacking platform 9B which is located aligned in the advancement direction of the sheets FA, FB, downstream of the first stacking platform 9A.

[0033] The first conveyor 5A comprises an inlet 10A and an outlet 12A. At the inlet 10A shingling members 11A are positioned, not described and per se known, which may for example comprise brushes, suctioning belts or other members which brake the sheets FA reaching to the conveyor 5A and cause the partial overlapping thereof to take a shingled condition. The sheets maintain the shingled arrangement up to the stacking platform 9A. The outlet 12A may be provided with output rollers, brushes or prongs, or other members for controlling the ejection movement of the sheets FA towards the stacking platform 9A.

[0034] Similarly, the second conveyor 5B comprises an inlet 10B and an outlet 12B. At the inlet 10B shingling members 11B are positioned, similar to the shingling members 11A, which brake the sheets FB reaching the second conveyor 5B and causes the partial overlapping thereof to take the shingled condition. The sheets FB maintain the shingled arrangement up to the stacking platform 9B. The outlet 12B may be provided with output rollers, brushes or prongs, or other members for controlling the ejection movement of the sheets FB towards the stacking platform 9B.

[0035] Each conveyor 5A, 5B may consist series of conveyor belts, as schematically shown in FIG. 1, which may advance at a speed that may be variable and different from each other, for example so as to generate a gap in the flow of shingled sheets, to allow the removal of a complete stack of sheets PA, PB from the stacking platform 9A, 9B and allow the start of the formation of a subsequent stack.

[0036] Along the path of each conveyor 5A, 5B a device for the lateral aligning the sheets FA, FB is arranged, which provides for correcting any skidding of the sheets FA, FB in the lateral direction, i.e., in a transverse direction with respect to the advancement direction of the sheets along the conveyors 5A, 5B. The overall advancement direction of the sheets FA, FB is generally and summarily indicated with F. The lateral aligning devices are indicated with 21A, 21B. The two devices 21A, 21B may be equal to each other. One of said aligning devices will be described below with reference to the following FIGS. 2 to 7 and indicated therein with 21.

[0037] The aligning device 21 comprises a first aligning member 23 and a second aligning member 25. The two aligning members 23, 25 may be symmetrical to each other and they are opposite with respect to each other.

[0038] The aligning members 23, 25 may be provided with various movements with respect to a stationary load-bearing structure, which also carries the respective conveyor 5A or 5B. Each aligning member 23, 25 is provided with a first adjustment movement in a direction orthogonal to the advancement direction F of the sheets FA, FB on the respective conveyor 5A, 5B. In FIGS. 2 to 7 this first movement is indicated with f23 for the aligning member 23 and with f25 for the aligning member 25. The adjustment movement according to f23 and f25 may be obtained by mounting each aligning member 23, 25 on a respective slide 33, 35, in turn supported on a transverse support, which extends transversely to the direction F. In the illustrated embodiment, the transverse support is indicated with 27 and consists of a transversal beam. Below, the transverse support will also be referred to as “beam” for the sake of brevity. Each slide 33, 35 is provided with a movement according to the longitudinal extension of the beam 27. In the illustrated embodiment, on the beam 27 there are integrally mounted guides 29 extending orthogonally to the direction F and parallel to the longitudinal extension of the beam 27. The latter is stationary to the load-bearing structure which supports the respective conveyor 5A or 5B.

[0039] A first slide 33 which carries the first aligning member 23 and a second slide 35 which carries the second aligning member 25 are engaged to the guides 29 by means of shoes 31.

[0040] The movement of the slides 33 and 35 according to the double arrow f23 and f25 may be controlled by a respective actuator 37 and 39, for example an electric motor, which rotates a pinion (FIG. 5 shows the pinion 40 of the actuator 37), meshing with a rack 41 that extends longitudinally along the beam 27 and is integrally joined therewith.

[0041] Each aligning member 23, 25 may comprise a plate 45, 47 with respective upstream and downstream edges (with respect to the advancement direction of the conveyor 5A, 5B) inclined with respect to the central portion of the plate 45, 47. Each plate 45, 47 is substantially orthogonal to the respective conveyor 5A, 5B and it may have an inclined upstream edge 45A, 47A and a bevelled downstream edge 45B, 47B. The inclined edges form a lead-in element for the sheets FA, FB which advance between the two aligning members 23, 25.

[0042] Each aligning member 23, 25 may be provided with a lifting and lowering movement with respect to the conveyor 5A, 5B. To this end, see FIG. 3, the first aligning member 23 is carried by the respective slide 33 by interposing a carriage 51 that is movable vertically according to a double arrow f51 with respect to the conveyor 5A / 5B and therefore with respect to the first slide 33. The carriage 51 may be connected to the first slide 33 through a vertical guide 52 integrally joined with the first slide 33 and through a shoe 54 integrally joined with the carriage 51, or vice versa. Similarly, see FIG. 4, the second aligning member 25 is carried by the respective slide 35 by interposing a carriage 53 that is movable vertically according to the double arrow f53 with respect to the conveyor 5A / 5B and therefore with respect to the second slide 35. The carriage 53 may be connected to the second slide 35 through a vertical guide 56 integrally joined with second slide 35 and through a shoe 58 integrally joined with the carriage 53, or vice versa.

[0043] The movement according to f51 of the carriage 51 may be controlled by an actuator 61, for example a cylinder-piston actuator. Similarly, the movement according to f51 of the carriage 53 may be controlled by an actuator 63, for example a cylinder-piston actuator. The lifting and lowering movement according to f51 may be useful during the step of transverse positioning of the aligning members 23, 25 (translation according to f23 and f25). The lifting movement in this case may also be used in case of jam-up, i.e., should the sheets be stuck along the conveyor, to facilitate the removal of sheets which may be stuck under the aligning members.

[0044] The plate 45 may be constrained to the carriage 51 through a further actuator, which imparts to the plate 45 a reciprocating motion having at least one motion component (indicated with f63) parallel to the plane defined by the conveyor 5A / 5B and orthogonal to the direction F. Similarly, the plate 47 may be constrained to the carriage 53 through a further carriage 67, which imparts to the plate 47 a reciprocating motion having at least one motion component (indicated with f67) parallel to the plane defined by the conveyor 5A / 5B and orthogonal to the direction F. The actuators which control the movement according to f63 and f67 may be cylinder-piston actuators, as shown by way of example in the drawing, or vibrators or vibrator feeder, or other actuators adapted to generate an alternating motion according to the direction f63 and f67, or at least with a component in such direction.

[0045] In advantageous embodiments, each carriage 51, 53 comprises respective rolling bodies 71 configured to rest on the conveyor 5A / 5B or on a plane adjacent to the conveyor 5A / 5B. In the illustrated embodiment, support planes 75 are provided at both sides of the conveyor 5A / 5B configured to rest thereon the respective carriage 51 or 53 when the carriage is positioned laterally outside the respective longitudinal edge of the conveyor belt which forms the conveyor 5A / 5B. The longitudinal edge of the conveyor belt is indicated with 77 in FIGS. 6 and 7. The rolling bodies 71 form means for supporting the carriages 51, 53. The use of rolling bodies, instead of shoes or other stationary means, for example, facilitates the resting of the carriages 51, 53 on the conveyor belt forming part of the conveyor 5A / 5B. In this manner, each carriage 51, 53 may rest on the conveyor with minimum friction. The distance between the aligning members 23, 25 and the upper surface of the conveyor 5A / 5B is therefore reduced to the minimum to prevent the sheets with smaller thickness from inadvertently passing under the aligning members.

[0046] The stacking device described above operates as described below with reference to the conveyor 5A, it being understood that the conveyor 5B may operate in an equivalent manner.

[0047] The sheets FA, which may be produced by transversely cutting a continuous corrugated board strip, are partially superimposed with respect to each other at the inlet 10A through shingling members 11A and advance in this condition up to the outlet 12A of the conveyor 5A / 5B. Here, the sheets are ejected and stacked on the stacking platform 9A, forming a stack PA. In order to allow the formation of the stack, the outlet 12A of the conveyor 5A and the stacking platform 9A have a relative movement in the vertical direction according to the double arrow f9. As known to those skilled in the art, the stacking platform 9A may move downwards during the formation of the stack Pa, while the conveyor 5A remains stationary. There cannot be ruled out the possibility of operating in the opposite manner, that is to hold the stacking platform 9A stationary, while the stack PA is formed by gradually lifting the outlet end 12A of the conveyor 5A. In both cases, the device 21A for lateral aligning of the sheets remains stationary with respect to the outlet 12A of the conveyor 5A.

[0048] Before starting the stacking operations, the aligning members 23, 25 are carried in the correct working position. This position is determined by the width of the sheets FA which advance on the conveyor 5A. The distance between the opposite surfaces of the plates 45, 47 is equal to the width of the sheets 5A, i.e., the distance between the longitudinal edges of each sheet 5A.

[0049] If, as shown in the exemplary embodiment, the aligning members 23, 25 have a reciprocating approaching and distancing movement (f63, f67), the minimum distance between the plates 45, 47 is set so as to be substantially equal to the width of the sheets FA.

[0050] The adjustment movement for setting the correct position of the aligning members 23, 25 is imparted by the actuators 37, 39 and is carried out by preferably holding the carriages 51, 53 raised with respect to the conveyor 5A, so that the positioning movement can be carried out without contact between the rolling bodies 71 and the underlying surfaces (conveyor 5A and support planes 73, 75). Once the slides 33, 35, the carriages 51, 53 and the plates 45, 47 have reached the correct position, the carriages 51, 53 can be lowered until the rolling bodies 71 rest on the conveyor 5A or on one or the other of the support planes 73, 75.

[0051] During stacking, the aligning members 23, 25 rest with the rolling bodies 71 on the upper surface of the conveyor 5A (or on one or on the other of the support planes 73, 75) and move cyclically and repeatedly according to f63 and f67 so as to repeatedly push with the plates 45, 47 against the edges of the sheets FA which pass between the aligning members. The frequency of the movement according to f63 and f67 may be set advantageously so that, at a given linear advancement speed of the sheets FA along the conveyor 5A, each sheet comes into simultaneous contact with the aligning members 23, 25 at least once. The cyclic, or repeated, and synchronised movement of the aligning members 23, 25 allows any lateral misalignments of the sheets FA to be corrected, so that each sheet FA arrives on the stacking platform 9A in the correct position, centred with respect to the stack 9A being formed.

[0052] The cyclic or repeated movement which brings the aligning members to cooperate with the longitudinal edges of the sheets FA (that is the edges parallel to the advancement direction F) dynamically facilitates the straightening and the correct orientation of the sheets FA. It cannot be ruled out that in some cases, for example with sheets that are small in size, the aligning effect can be obtained passively, that is holding the aligning members 23, 25 in a fixed position and using for the aligning the geometric shape for guiding the inlet edges 45A, 47A of the plates 45, 47.

Examples

Embodiment Construction

[0030]By way of summary, in order to alleviate or solve the problem of laterally aligning the sheets stacked on the stacking platform, a stacking device is provided which comprises, along the sheet supplying conveyor, a pair of opposite aligning members, which cooperate with the longitudinal edges of the sheets which advance, in a shingled configuration, along the conveyor. The aligning members act passively or actively on the sheets, to align them, so that their longitudinal edges are correctly positioned in the transversal direction, that is orthogonal to the advancement direction. In this manner, the sheets are stacked in an orderly and aligned manner on the stacking platform, without the need for aligning members downstream of the conveyor.

[0031]Referring now to the drawings, FIG. 1 schematically illustrates the final part of a line for producing corrugated board sheets, indicated in its entirety with 1. In this part of the line a stacking device 3 is provided, which basically f...

Claims

1. A device for stacking sheets comprising a stacking platform, and a conveyor with an inlet and an outlet, the inlet adapted to receive shingled sheets and the outlet positioned to discharge the sheets on a stack of sheets being formed on the stacking platform;wherein along the conveyor, upstream of the outlet of the conveyor, a first aligning member and a second aligning member are arranged, opposite to each other and adapted to cooperate with longitudinal edges of the shingled sheets which advance along the conveyor, to align them with respect to the stack being formed on the stacking platform;wherein the first aligning member and the second aligning member are supported on a transverse support, extending transversely to an advancement direction of the conveyor, respectively by a first slide which can be adjusted in position along the transverse support, and by a second slide which can be adjusted in position along the transverse support; andwherein each of said first slide and said second slide comprises an actuator for moving a respective one of said first slide and said second slide along the transverse support.

2. The stacking device of claim 1, wherein each of said first aligning member and said second aligning member is provided with a repeated transverse movement to repeatedly move respective longitudinal edges of the shingled sheets which advance along the conveyor.

3. The stacking device of claim 2, wherein each of said first aligning member and said second aligning member comprises a respective actuator which imparts to a respective one of said first aligning member and said second aligning member a repeated movement with at least one motion component orthogonal to the advancement direction of the conveyor and parallel to a support surface of the conveyor.

4. The stacking device of claim 1, wherein each of said first aligning member and said second aligning member comprises a respective actuator which moves the aligning member with respect to a respective one of said first slide and said second slide with a repeated movement having at least one motion component orthogonal to the advancement direction of the conveyor and parallel to a support surface of the sheets on the conveyor.

5. The stacking device of claim 3, wherein each said respective actuator comprises a cylinder-piston actuator or a vibrator.

6. The stacking device of claim 1, wherein each of said first aligning member and said second aligning member comprises a respective actuator configured to lift and lower the alignment member relative to the conveyor.

7. The stacking device of claim 1, wherein each of said first aligning member and said second aligning member comprises at least one rolling body for resting on the conveyor or a plane adjacent to the conveyor.

8. The stacking device of claim 1, wherein each of said first aligning member and said second aligning member comprises a plate approximately orthogonal to the conveyor.

9. The stacking device of claim 8, wherein the plate comprises an inclined lead-in edge facing towards the inlet of the conveyor.

10. A method for forming stacks of superimposed sheets with a stacking device comprising a stacking platform, and a conveyor with an inlet and an outlet, the inlet adapted to receive shingled sheets and the outlet positioned to discharge the sheets on a stack of sheets being formed on the stacking platform;wherein along the conveyor, upstream of the outlet of the conveyor, a first aligning member and a second aligning member are arranged, opposite to each other and adapted to cooperate with longitudinal edges of the shingled sheets which advance along the conveyor, to align the shingled sheets with respect to the stack being formed on the stacking platform;wherein the first aligning member and the second aligning member are supported on a transverse support, extending transversely to an advancement direction of the conveyor, respectively by a first slide which can be adjusted in position along the transverse support, and by a second slide which can be adjusted in position along the transverse support; andwherein each of said first slide and said second slide comprises an actuator for moving the respective one of said first slide and said second slide along the transverse support; the method comprising steps as follows:supplying a flow of said shingled sheets along the conveyor, from the inlet of the conveyor towards the outlet of the conveyor;discharging the shingled sheets from the outlet of the conveyor on a stacking platform, gradually moving the stacking platform and the outlet of the conveyor away from each other; andmutually aligning the shingled sheets along the conveyor, upstream of the outlet of the conveyor.

11. The method of claim 10, wherein said mutually aligning the shingled sheets comprises transversely pushing the shingled sheets simultaneously through the first aligning member and the second aligning member, opposite to each other.

12. The method of claim 11, wherein each of said first aligning member and said second aligning member is provided with a repeating transverse movement which generates a dynamic thrust in a direction transversal to the longitudinal edges of the shingled sheets which advance along the conveyor.

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