EP4144677A1 - Device and method for positionally defined transport of sheets - Google Patents

Abstract

Shown and described is a device (1), in particular a roll cross cutter, for forming an imbricated flow of sheets (3) that overlap or overlap, in particular of paper or cardboard sheets, with a transport device for transporting sheets, with a shingling device (10) for region-wise Overlapping or undercutting of the sheets (3), with a braking device (17) following the shingling device in the transport direction (X) of the sheets (3) for braking shingled sheets (3), in particular by forming a braking gap for the passage of shingled sheets brought together (3), and with a transverse cutting device (5) upstream of the shingling device (10) for cutting a strip of material into individual sheets (3). According to the invention, a suction section (24, 25) is provided between the shingling device (10) and the braking device (17) for sucking in and transporting a sheet (3) trailing in the shingled stream into the braking device (17).

Description

The invention relates to a device, in particular a so-called roll cross cutter, for forming an imbricated flow of sheets that overlap or overlap, in particular sheets of paper or cardboard, with a transport device for transporting sheets, with a shingling device for overlapping or undercutting the sheets in certain areas, with a braking device downstream of the shingling device in the transport direction of the sheets for braking shingled sheets, in particular by forming a braking gap for the passage of sheets brought together in a shingled manner, and with a cross-cutting device upstream of the shingling device for cutting a strip of material into individual sheets. In addition, the invention relates to a method for forming an imbricated stream of sheets that overlap or overlap, in particular foils, sheets of paper or cardboard, more particularly for forming an imbricated stream of individual sheets cut from a strip of material with a cross cutter, with individual sheets being fed to an imbricating device are transported and partially overlapped or undercut in order to produce an imbricated stream, and the imbricated sheets are braked with a braking device which follows the imbricated device in the transport direction of the sheets.

A roll sheeter is, for example, from DE 101 03 040 A1 known. With the known roll cross cutter, sheets of paper or cardboard can be provided as a quasi-endless band in the form of a paper roll. With the aid of a feed device with rollers or rollers, the strip is fed to a cross-cutting device, where it is cut into sheets of a defined length. A paper reservoir is often connected upstream of the feed device in order to keep available a certain web length of the paper. The cut sheets are fed to a shingling device with the help of high-speed conveyor belts to form an underlap of the sheets. The shingling device includes a lifting shaft and a suction belt arranged above it. The sheets running through the shingling device are lifted at a defined point on the sheets, in particular relative to the trailing edge of the sheets, by the lifting shaft in relation to the transport plane and are pressed onto the suction belt arranged above. The suction belt has a lower peripheral speed than the high-speed conveyor belts that transport the sheets from the cross-cutting device. The sheet is thus decelerated when the trailing edge of the sheet is lifted off the lifting shaft is pressed against and held by the suction belt arranged above it. The scale device acts as the first, rear brake unit.

A braking device is arranged downstream of the shingling device in the transport direction of the shingled stream as a second, front braking unit. Such a braking device is, for example, in DE 38 12 685 A1 described. The braking device can have at least one so-called nip roller, which forms a braking gap together with a conveyor belt, another roller or a roller. The distance between the braking device and the stacking device is set in such a way that the leading sheet edge of a sheet preferably just enters the braking gap of the braking device and is decelerated when the rear sheet area, in particular the trailing edge of the sheet, is pressed onto the suction belt by the lifting shaft of the stacking device . In this way, the sheet is braked or decelerated preferably simultaneously by the nip roller in the front sheet area and by the suction belt of the shingling device in the rear sheet area. The simultaneous deceleration of the sheet in the area of its leading and trailing edge prevents the sheet from rippling during braking. The trailing sheet has a higher speed than the leading sheet that has already been turned up. Since the leading sheet is held up with its trailing edge on the suction belt, the leading edge of the trailing sheet can be conveyed under the leading sheet. Thus, due to the difference in speed between the leading and trailing sheets, the sheets will overlap. In this way, a continuous imbricated stream is generated. Following the braking device, the shingled stream formed by the underlapped sheets is transported at the same speed and with the same shingle length of the underlapped sheets onto a transfer table with slow-running conveyor belts to a further processing machine.

As described in the previous paragraph, the sheets are braked at approximately the same time at their leading and trailing edges. Particularly in the case of long sheet formats, the sheets can sag, with a sagging leading sheet being able to impede the forward movement of a following sheet. This can lead to problems with the positioning accuracy of the following sheets at the braking nip. In order to prevent the arches from sagging, the arches are pulled up by the suction belt after being pushed up by the beater shaft, held and then tightened or tensioned.

The sheets are tensioned by setting the speed of the suction belt slightly lower than the speed of the nip rollers of the braking device. Due to the tensile forces exerted on the sheet by the difference in speed between the nip rollers and the suction belt, the sheet is tensioned and sagging is reduced. If the leading sheet is conveyed out of the engagement area of the suction belt, it is no longer held by the suction belt. A falling sheet would impede the front edge of the trailing sheet in such a way that it would no longer be possible to shingle under in a defined position. Due to the higher friction caused by the dead weight of the preceding sheet, the following sheet, which is running faster, would be hindered in its forward movement. For this reason, a sheet folded up with its trailing edge remains longer than one cycle in the effective range of the suction belt. A cycle is the length of time between the beating up of a first leading sheet and the beating up of a second trailing sheet. This ensures that the leading sheet, when it leaves the area of influence of the suction belt, is held up by a trailing sheet that has been turned up and has already been sucked in, since the trailing edge of the trailing sheet is then already in the effective area of the suction belt and the trailing sheet the leading sheet holding up bow. Accordingly, the suction belt must apply a sufficiently high suction capacity in order to be able to securely hold both the folded sheets and the sheets held by the folded sheets.

With increasing sheet length, the weight of the leading sheet increases, which has to be carried by the trailing sheet. This increases the risk of the sheets sagging with large sheet formats. Furthermore, despite the difference in speed between the slow-running conveyor belts and the suction belt of the shingling device that guides the trailing edge of the sheet, it is not possible to completely prevent the sheets from sagging. For this reason, there is a greater sagging of the leading sheets, especially with long sheet formats, as a result of which a braking effect on the leading edge of the following sheet can be generated by frictional contact. This has a negative effect on the positioning and location of the trailing sheet. A sheet that has slipped or is not positioned optimally in the shingled stream can lead to position errors and damage to the sheet, but also to a standstill of the entire device.

The object of the present invention is to provide a device and a method of the type mentioned at the outset, which enable a precise or defined feed of a trailing sheet in the sheet flow into the braking device. In addition, even at high transport speeds, damage caused by the sheets entering the braking device in an inaccurate manner should be reliably avoided.

In a device of the type mentioned at the outset, the above-mentioned object is achieved according to the invention in that in the region between the shingling device and the braking device, a suction section, preferably below the transport plane of the sheets, is provided for further transport of the sheet leading edge of a sheet following in the shingled stream into the braking device. Accordingly, in the method according to the invention, it is provided that the following sheets of an imbricated flow are transported into the braking device preferably from below under the effect of suction.

The invention is based on the basic idea of feeding the front edges of the following sheets to the braking device in a defined manner by means of suction in the region between the shingling device and the braking device. The leading edge of a trailing sheet is in this case at least partially moved further relative to a leading sheet, the leading edge of the sheet being sucked in from below in the event of shingling and being located below a leading sheet. In the case of overlapping, the leading edge of a trailing sheet is sucked in from above and is then located above the leading sheet. This significantly increases the positioning accuracy of the leading edge and thus of the entire sheet. The invention can also be used to prevent damage to the sheet at the braking point, which can result from inaccuracies in the position of the leading edge.

The suction section is formed, for example, in the case of shingling, by generating a negative pressure below the transport level of the sheets. It goes without saying that the solution according to the invention can also be implemented in an appropriately adapted manner in connection with the overlapping of the arches.

At least one suction device is provided to form a suction path. For example, the suction device can interact with at least one suction belt, which is moved in the transport direction and is used to transport the sheets further after they have passed the shingling device. the negative pressure generated by the suction device is designed in such a way that at least the leading edge or a region of the leading edge of a sheet is held in place in such a way that the sheet is transported in a desired position with precise positioning.

The suction section is preferably formed by a plurality of suction belts which are arranged one behind the other transversely to the transport direction and run parallel to one another. The sheets are sucked in and transported via the suction belts. Each of the suction belts can be assigned its own suction device. However, it is also possible that only a single suction device, for example a suction box, is provided, via which negative pressure is generated for all suction belts. Alternatively, it is also possible for the suction section to be formed by a plurality of conveyor belts, which are arranged one behind the other transversely to the transport direction and run parallel to one another, in which case no negative pressure is generated via the conveyor belts. In this embodiment, suction zones located between the conveyor belts can be formed to generate negative pressure. The suction device is then designed to generate a negative pressure in the area of the suction zones, which acts on the sheets and pulls them against the conveyor belts during sheet transport by means of the conveyor belts.

A sheet whose front edge reaches the area of the suction path is attracted at least in the area of the front edge of the sheet and is thus transported in a defined position in the transport direction of the sheets. The front edge of the sheet is fixed on at least one suction belt or conveyor belt in such a way that the front edge of the sheet does not become detached during transport. For this reason, the leading edge of the sheet can be transported into a braking gap of the braking device without being damaged. When shingling under, the trailing edge of the sheet in the shingling device can be pressed simultaneously with the entry of the leading edge of the sheet into the braking device by a beater shaft of the shingling device against a suction belt of the shingling device arranged above it. The trailing edge of the sheet is then held up by the suction belt of the shingling device and simultaneously decelerated in the area of the sheet leading edge and the sheet trailing edge. The trailing sheet can continue to be located on the high-speed transport device, with at least the area of its leading edge reaching the area of the suction path. The trailing sheet is at a higher speed relative to the leading sheet with a defined location or position in the transport direction of the sheets conveyed below the leading sheet to the braking device. This prevents the leading edge of the sheet from detaching from the intake section. The following sheet can thus be conveyed to the braking device below the preceding sheet without being impaired and without colliding with the preceding sheet. In this way, the arc current is shingled under. Those skilled in the art know that with a different arrangement, the arc current can also be overlapped. The invention thus explicitly relates to both under-scaling and over-scalding of the arc current.

A further suction section is preferably provided between the cross cutter and the shingling device. The suction section between the shingle device and the braking device and the further suction section can be formed with the same suction device or with several separate suction devices. The additional suction section is used to transport the sheets in a desired position and location in a defined manner from the cross cutter to the shingle device. This achieves a high level of positioning accuracy for the sheets, which is necessary since both the cross cutter and the shingling device have to work in the same cycle as the further processing machine. Because of this clocking, it is important that the leading edge of the sheet assumes a position or position that is defined at that point in time. Of course, the positional accuracy refers to the entire arc.

Furthermore, it can be provided that the suction path between the shingled device and the braking device and the further suction path in the region of the shingled device are interrupted. Between the suction section between the shingling device and the braking device and the further suction section there is then an area in the transport plane of the sheets in which no negative pressure or a significantly lower negative pressure is generated. This is particularly advantageous if the trailing edge of the sheet is turned up by means of a beater shaft. This makes it easier to turn up the trailing edge of a sheet, since no or a significantly reduced suction force acts on the trailing edge of the sheet when it is turned up. The suction section is designed in such a way that the sheet is sucked in at least in the area of the leading edge and is conveyed in a defined position in the transport direction while and after the sheet trailing edge is gripped by the beater shaft and pressed against the suction belt of the stacking device above it. Because in the area of Racquet shaft of the shingling device has no or significantly reduced suction force on the sheet, the stresses that a sheet experiences when it is turned up are reduced. A strong suction effect on the trailing edge of a sheet when it is folded up could result in the sheet being damaged when it is folded up or slipping out of its defined position.

Advantageously, the pressure level in the area of the suction section between the shingle device of the braking device is lowered less than in the area of the further suction section between the cross cutter and the shingle device. In this context, less strong means that the pressure difference between the negative pressure generated in the intake section between the shunting device and the braking device and the ambient pressure is less strong than in the area of the further intake section. The result of this is that the sheet is pulled with great force in the area between the cross cutter and the shingling device in order to achieve high positional accuracy. The sheet, or at least the leading edge of the sheet, is attracted less strongly in the area of the intake path between the shingling device and the braking device. The different levels of vacuum on both sides of the shingle device enable precise and rapid sheet transport from the cross cutter to the braking device.

It can be expedient if in the area of the intake path between the shunting device and the braking device there is a pressure reduction compared to the ambient pressure of less than 2 mbar, preferably less than 1 mbar, more preferably less than 0.5 mbar, particularly preferably less than 0. 1 mbar, takes place. However, the pressure reduction can also be significantly higher and a pressure reduction compared to the ambient pressure of 0.5 to 10 mbar, preferably between 1 to 5 mbar, in particular up to 2 mbar, can be provided. By reducing the pressure, it is achieved in an advantageous manner that the leading edge of the sheet, and thus the entire sheet, can be transported in a defined position.

In a further advantageous manner, the pressure drop in the area of the further intake path, ie in the area between the cross cutter and the shingle device, is ten to a hundred times greater than in the area between the shingle device and the braking device. Due to the stronger negative pressure, the sheets are transported from the cross cutter to the shingling device in the exact position.

In an advantageous embodiment, the shingling device is designed to be adjustable in and/or counter to the transport direction of the sheets, depending on the cut length. This enables the device to be easily adapted to a changed sheet format. The term "cut length-dependent" refers to a change in the arrangement of the shingling device relative to the cross cutter and, preferably, relative to the braking device, for a format change of the sheet. In a further advantageous embodiment, the braking device is designed so that it cannot be adjusted in and/or counter to the transport direction of the sheets. The distance between the transfer point and the braking device is therefore the same for every sheet format, i.e. it is independent of the cutting length.

Depending on the current (new) sheet length, the shingling device can then be moved, offset or shifted relative to the braking device in or counter to the transport direction of the sheets, so that for each adjustable sheet length, a leading sheet is removed from the braking device at the front and from the rear at about the same time Schuppeinrichtung is braked. In particular, it is possible to keep the distance between the transfer point and the braking device or the transfer length constant during a format change, with the braking device preferably not being adjusted during a format change. Instead, the distance between the braking device, which is preferably arranged in a stationary manner, and the shingling device is adapted to the actual sheet length by adjusting the shingling device. The distance between the front transfer point of the sheets to a sheet processing machine and the braking device or the transfer length for different formats or cutting lengths remains the same, which leads to a considerable simplification when setting the device to a different sheet format. In particular, if the transfer length remains the same, there is no need to change the overlapping length of the sheets in the shingled stream when there is a format change.

In addition, a defined stopping point of the device can be defined, which is the same for every sheet format. The degree of overlapping or the overlap length can be kept the same for each sheet format with a fixed distance between the transfer point and the braking device. The length between the transfer point and the braking device corresponds exactly to an integer multiple of the shingling length. During a stop, the leading sheet is always within the suction belt's sphere of influence, allowing the following sheet to slide under the leading sheet. In the event of a system stop, a trailing sheet can fall under the leading one Arch are transported further. This makes it possible to slow down the fast-moving belts to a lesser extent or less quickly than the slow-moving belts, since the overlapping length acts as a buffer for the following sheet. The material stress on the high-speed belts and their braking units can be significantly reduced as a result. Since the risk of an uncontrolled slipping of a sheet is minimized by the reduced deceleration, the deceleration of the sheets does not have to be assisted as much. This can further reduce the energy requirement when the system stops. When restarting the device, the slow-moving tapes can be driven just before the fast-moving tapes, whereby the correct phasing in the device is restored. In this context, phasing means that the relative position of the sheets to the beater shaft and the position of the knives on the cross cutting device always assume a fixed position relative to one another. A system start is therefore possible in a simple manner and in a short time.

In addition, the device can be prevented from being stopped when the transverse cutter is in the process of cutting. Stopping the device while the cross-cutting device is in the process of making the cut can lead to uncontrolled damage to the sheet and/or the material web. In this respect, stopping the device during the cut is to be avoided. Since the trailing sheet has the shingling length or the overlapping length as a buffer compared to the leading sheet that has already been turned up, the slow-moving conveyor belts and the cross-cutting device can be stopped in a targeted manner such that the cross-cutting device stops outside the cut.

Advantageously, the transport device has at least one suction belt, in particular a belt arrangement with several suction belts running parallel to one another, with the suction belt being guided continuously in the transport direction of the sheets from the cross cutter to the braking device, i.e. over both suction sections and the area of the shingling device. Thus, only one preferably fast-running suction belt or only one belt arrangement extends over the two suction sections and the area of the shingling device. This achieves easy and simple control. A synchronization of conveyor sections arranged one after the other in the direction of transport is therefore not necessary. Alternatively, however, belt stretches that are separate from one another can also be used be provided to allow sheet transport in the area of the two intake sections.

Advantageously, at least one suction device is provided to form a suction path, the suction device having a suction profile or a suction box. By using a suction profile or a suction box, the generated negative pressure can be generated in a targeted and locally limited manner. Advantageously, a continuous suction profile is provided, in particular an arrangement of several suction profiles arranged one behind the other transversely to the transport direction of the sheets, or a continuous suction box for pressure reduction and formation of the suction path between the shingling device and the braking device and for formation of the further suction path. A continuous suction profile from the cross cutter to the braking device enables simple sealing and adjustment of the vacuum generation over the profile length in the transport direction of the sheets.

In a preferred embodiment, a discontinuous or non-continuous reduction in the pressure drop or a sudden pressure drop is provided over the length of the suction profile or suction box in the area of the imbricating device. This means that the negative pressure in the suction profile in the area of the overlapping device increases from a lower negative pressure in the transport direction of the sheets before the overlapping device to a less deep negative pressure after the overlapping device. For this purpose a single uninterrupted suction profile or a single, uninterrupted or continuous suction box can be provided, with the vacuum level in the suction profile or suction box being divided by a barrier or seal. In other words, the length of the intake sections can be changed by changing the position of the barrier. The barrier or seal causes a non-continuous change in pressure drop over the length of the suction profile or suction box. The position of the sudden increase in pressure in the suction profile or suction box in the transport direction of the sheets can be easily changed by the movable barrier and aligned with the position of the shingling device, especially if the shingling device is designed to be adjustable depending on the sheet format.

In a further preferred embodiment of the invention, the movable barrier or seal is designed to be adjustable together with the shingling device in and/or counter to the transport direction of the sheets. The common adjustability can be achieved in that a common carriage is provided for the shingling device and the movable seal or barrier, with the common carriage being designed to be adjustable in and/or against the transport direction of the sheets. The location of the non-constant pressure change migrates when the imbricating device is adjusted with the position of the imbricating device in or against the transport direction of the sheets. This ensures that at least at the location of the shingling device, there is always a lower pressure level than in the area between the cross cutter and the shingling device.

Alternatively, at least one telescoping suction profile and/or at least two suction profiles that mesh with one another can be provided to form a length-variable suction path between the shingling device and the braking device. Telescoping and/or intermeshing suction profiles represent simple mechanical configurations of length-changeable suction devices. In this case, telescoping means that several complementary suction profiles can be pushed into one another and the length of the entire suction profile can thus be changed. It must be ensured here that the two complementary, intermeshing suction profiles are tightly connected to one another, for example with the aid of a dynamic seal, so that a substantially identical pressure profile can be achieved over the length of the suction profile.

The suction section can also be formed from suction profiles arranged in alternation, with a first suction profile starting in the transport direction from the shingling device and a second suction profile against the transport direction from the braking device, and the two suction profiles overlap at least in sections transversely to the transport direction. The two suction profiles can be displaced in such a way that they mesh with one another until the front edge of one suction profile reaches the rear edge of the other suction profile and vice versa. Then the maximum length of the intake section is reached.

Both of the above-mentioned options for forming a length-variable intake path between the shingle device and the braking device also permit an adjustable arrangement of the braking device relative to the shingle device. If the braking device is to be adjusted in and/or against the transport direction of the sheets, for example in order to adapt the device to a changed sheet format, the suction path between the shingling device and the braking device can be easily adapted to the changed length between the shingling device and the braking device.

The embodiments of the invention described above can be combined with one another as required. The disclosure content of the invention is not limited to the combinations of inventive features specified by the selected paragraph formatting.

Further features of the present invention result from the following description of an exemplary embodiment of the invention with reference to the drawings and the drawings themselves. All features described and/or illustrated form the subject matter of the present invention alone or in any combination, regardless of their summary in the claims or their reciprocal relationships.

Fig. 1

eine schematische Darstellung einer Vorrichtung zur Bildung eines Schuppenstroms von unterlappenden Bögen nach dem Stand der Technik in einer Seitenansicht,

Fig. 2

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung zur Bildung eines Schuppenstroms von unterlappenden Bögen im Betriebszustand in einer Seitenansicht,

Fig. 3

eine schematische Darstellung einer weiteren Ausführungsform einer erfindungsgemäßen Vorrichtung zur Bildung eines Schuppenstromes von unterlappenden Bögen im Betriebszustand in einer Seitenansicht und

Fig. 4

eine schematische Darstellung einer weiteren Ausführungsform einer erfindungsgemäßen Vorrichtung zur Bildung eines Schuppenstroms von unterlappenden Bögen im Betriebszustand in einer Seitenansicht.

The invention is explained in more detail below with reference to the figures; show it

1

a schematic representation of a device for forming an imbricated flow of underlapping sheets according to the prior art in a side view,

2

a schematic representation of a device according to the invention for forming an imbricated stream of overlapping sheets in the operating state in a side view,

3

a schematic representation of a further embodiment of a device according to the invention for forming an imbricated stream of overlapping sheets in the operating state in a side view and

4

a schematic representation of a further embodiment of a device according to the invention for forming an imbricated stream of overlapping sheets in the operating state in a side view.

In 1 a device 1 known from the prior art for forming a sheet stream 2 from underlapping sheets 3 made of paper, film or cardboard is shown schematically. The device 1 has a feed device, not shown, which promotes a quasi-endless strip of paper or cardboard 4 . The tape is with an unwinding device, not shown, from a paper or Cardboard roll provided on a feed side and can be passed through an intermediate paper store. A cross cutting device 5 downstream of the feed device (not shown) in the transport direction X of the sheets 3 cuts the strip 4 into sheets 3 of a defined length. The transverse cutting device 5 is designed in the form of a rotatably mounted shaft 6 which has a cutting edge 7 on its circumference. If the cutting edge 7 arranged on the shaft 6 and a fixed cutting edge 8 are engaged, the strip 4 is cut. The sheet length can be adjusted by changing the rotational speed of the shaft 6 and the feed speed.

The sheets 3 are transported further in the transport direction X on a conveyor belt with at least one fast-moving conveyor belt 9 . A belt section with a plurality of conveyor belts 9 is preferably provided, which lie one behind the other transversely to the direction of transport X and are spaced apart from one another. The following statements on the conveyor belt 9 refer to this belt section.

A shingling device 10 following the cross-cutting device 5 consists of a lifting unit 11 and a delay unit 12. The delay unit 12 has at least one suction belt 13 arranged above the transport plane Y of the sheets 3. The suction belt 13 is formed by a conveyor belt provided with holes, which cooperates with a suction box 14 that generates a vacuum. The lifting unit 11 has a beater shaft 15 with at least one beater 16 . The beater 16 of the lifting unit 11 presses a sheet 3 against the suction belt 13 with each revolution of the beater shaft 15. Since the suction belt 13 is moved at a lower speed than the fast-moving conveyor belt 9, the front edge of a trailing sheet 3 is under the raised rear edge of a leading arch 3 promoted. With the next rotation of the beater shaft 16, the trailing sheet 3 is lifted at the rear edge, so that the sheet 3 that is further trailing can be conveyed under the trailing sheet 3. In this way, an arc stream 2 of underlapping arcs 3 is generated. If the trailing edge of the leading sheet 3 is no longer in the gripping area of the suction belt 13, the leading sheet 3 is held above the transport level by the trailing sheet 3, since the trailing sheet 3 is already being held up by the suction belt 13 before the leading sheet 3 leaves the gripping area of the suction belt 13 leaves.

After the shingle device 10 is in the transport direction X of the sheet flow 2 a Braking device 17 is provided. The braking device 17 has at least one nip roller 18 which, together with at least one slowly running conveyor belt 19, forms a braking gap. The distance between the braking device 17 and the shingling device 10 is set in such a way that the front edge of a sheet 3 preferably just enters the braking gap and is decelerated when the rear sheet area, in particular the rear edge of the sheet 3, has passed from the beater 16 of the lifting unit 11 the suction belt 13 is pressed. In this way, the sheet 3 is braked or decelerated preferably approximately at the same time by the nip roller 18 and the slow-running conveyor belt 19 in the front area and by the suction belt 13 in the rear sheet area. In order to stretch the sheet and reduce sagging of the sheet, the suction belt 13 has a slightly reduced speed compared to the slow-running conveyor belt 19. Following braking device 17, sheet flow 2 is conveyed at the same speed and, in particular, with substantially the same stream length, i.e. at the same distance from the leading edge of leading sheet 3 to the leading edge of trailing sheet 3, on a transfer table (not shown) to a transfer point (not shown). further processed machine transported.

A suction box 20 can be arranged below the conveyor belt 9 in the area between the cross-cutting device 5 and the shingling device 10 . The conveyor belt 9 is then preferably designed as a suction belt. A negative pressure is generated in the suction box 20, as a result of which the sheets are drawn against the conveyor belt 9. As a result, the sheet 3 or the material web 4 is transported on the conveyor belt 9 before, during and after cutting in the cross cutting device 5 .

As in 1 As can be seen, the braking device 17 is designed to be adjustable in and/or counter to the transport direction X of the sheets 3. This is represented by the double arrow 21. If the device 1 is converted to a different sheet format, the braking device 17 is adjusted in such a way that the distance between the braking device 17 and the shingling device 10 essentially corresponds to the sheet length of the new sheet format. The distance between the braking device 17 and the shingling device 10 should be adjusted in such a way that the sheet 3 is braked essentially simultaneously at its front edge by the braking device 17 and at its rear edge by the suction belt 13 of the shingling device 10.

Depending on the current (new) sheet length, the shingling device 10 can then be moved, offset or shifted relative to the braking device 17 in or against the transport direction of the sheets 3, so that for each adjustable sheet length a leading sheet 3 is approximately simultaneously in front of the braking device 17 and is braked at the rear by the scale device 10. In particular, it is possible to keep the distance between the transfer point and the braking device 17 or the transfer length constant during a format change, with the braking device 17 preferably not being adjusted during a format change. Instead, the distance between the braking device 17, which is preferably arranged in a stationary manner, and the shingling device 10 is adapted to the actual sheet length by adjusting the shingling device 10. The distance between the front transfer point of the sheets 3 to a sheet processing machine and the braking device 17 or the transfer length for different formats or cutting lengths remains the same, which leads to a considerable simplification when setting the device to a different sheet format. In particular, if the transfer length remains the same, there is no need to change the overlapping length of the sheets 3 in the scale stream when there is a format change.

It has changed at the in 1 Device 1 shown shown that the transport of the sheet leading edge of the sheet 3 between the shingle device 10 and the braking device 17 is prone to failure. In this way, the leading edge of the sheet 3 can be detached from the fast-moving conveyor belt 9, particularly at high transport speeds. If the leading edge of the sheet detaches from the conveyor belt 9, the sheet 3 can be damaged when it enters the braking gap of the braking device 17. Furthermore, the sheet 3 can be brought out of position by detaching the leading edge of the sheet, so that an imprecise shingle length is then formed between the leading edge of the leading sheet 3 and the leading edge of the trailing sheet 3 . In addition, the leading edge of the sheet can come into frictional contact with the leading sheet 3 when it is detached from the fast-moving conveyor belt 9 or slips. As a result, the sheet 3 can also be decelerated, so that the desired shingle length is also not reached.

In 2 another device 1 for forming an imbricated stream 2 of overlapping sheets 3 is shown schematically in a side view. Identical or matching functional units, assemblies, components and other matching features in the Figures 1 and 2 shown device 1 are provided with the same reference numbers. The formation of an imbricated stream 2 of overlapping sheets 3 of paper, foil or cardboard takes place in the in 2 shown embodiment corresponding to the above-described imbricated stream formation in the device 1 1 .

Deviating from the in 1 Device 1 shown is in accordance with the embodiment 2 provided that the shingle device 10 is designed to be adjustable in and/or counter to the transport direction X depending on the sheet length or the sheet format. this is in 2 shown schematically by the double arrow 21. The braking device 17, on the other hand, is non-adjustable in and/or opposite to the transport direction X of the sheets 3. In other words, this means that when the cutting length of the sheets 3 changes or when the sheet format changes, the shingling device 10 is offset, shifted or moved relative to the braking device 17 in such a way that a leading sheet is produced for each sheet length that is set 3 is braked approximately simultaneously at the front by the braking device 17 and at the rear by the delay unit 12 of the shingle device 10 . The distance between the transfer point (not shown) of the sheets 3 to a further processing machine and the braking device 17 or the transfer length for different formats or cut lengths of the sheets 3 remains the same, which simplifies the setting of the in 2 shown device 1 leads to a different sheet format. For a format change, the stacking device 10 can be adjusted overall in or counter to the transport direction X of the sheet flow 2, i.e. the lifting unit 11 and the delay unit 12 are moved together, which for this purpose are in and/or counter to the transport direction X of the sheets 3 movable chassis or frame or carrier can be included or mounted. In principle, however, it is also possible that if the suction belt 13 extends sufficiently in the transport direction X, only the beater shaft 15 with the beater 16 is adjusted in or against the transport direction X.

At the in 2 In the device 1 shown, a suction profile 22 is provided between the shingling device 10 and the braking device 17 below the high-speed conveyor belt 9, which profile is designed as a hollow profile and is connected to a suction device (not shown), such as a suction fan. In a belt section with a plurality of conveyor belts 9 designed as suction belts, each conveyor belt 9 is preferably assigned a suction profile 22 .

Above a longitudinal section of the suction profile 22 and the associated section of the conveyor belt 9, a first suction section 24 is formed between the shingling device 10 and the braking device 17, and a further suction section 25 is formed in the area between the shingling device 10 and the cross-cutting device 5. A negative pressure acts on the sheets 3 at least in the area of the leading edge of the sheets 3 via the suction profile 22 and the conveyor belt 9. The applied negative pressure prevents the leading edge of a sheet 3 from becoming detached. At the same time, the formation of the suction section 24 means that the following sheet 3 is transported further in a defined position after it has passed the shingling device 10 . It is thus possible for the arches 3 to overlap in a defined manner without the arches 3 interfering with one another. The suction profile 22 preferably extends over the entire length of the area between the cross-cutting device 5 and the braking device 17. In the area in front of the shingling device 10, the further suction section 25 is formed by the suction profile 22.

The negative pressure applied to the suction profile 22 should be significantly less strong in the area of the suction section 24 following the shingling device 10 in the transport direction X than the negative pressure present in the area of the further suction section 25 between the cross-cutting device 5 and the shingling device 10. In the area of the shingling device 10, more precisely in the area of the beater shaft 15 with the beater 16, a section 23 is provided on which no negative pressure or a comparatively less strong negative pressure is applied. In this way, the sheet 3 can be lifted in the area 23 and pressed against the suction belt 13 in a simple manner. In the area of the trailing edge of the sheet, the lifting unit 11 therefore does not have to counteract a negative pressure that would hold the trailing edge of the sheet 3 on the fast-moving conveyor belt 9 . It is thus possible for the trailing sheet 3 to be transported in the correct location and position under the leading sheet 3 that has been folded up, while at the same time the trailing edge of the sheet can be pressed against the suction belt 13 by the beater 16 without being adversely affected.

The suction profile 22 can preferably be formed by a continuous hollow profile. The different levels of vacuum in the area of the suction section 24 and the suction section 25 can be achieved by a barrier or seal in the area of the scale device 10 . In this case, it is possible to provide only one vacuum-generating device that is connected to the suction profile 22 in the Area of the intake section 25 is connected. At the same time, a low negative pressure is generated in the intake path 24 via the barrier. The pressure reduction in the area of the intake section 24 compared to the ambient pressure is preferably significantly lower than the pressure reduction in the area of the intake section 25.

It is advantageous if the barrier in the profile that forms the suction sections 24, 25 is designed to be movable, in particular displaceable, in and/or counter to the transport direction X of the sheets 3. Thus, the length of the intake section 24 can be adapted to the sheet format in a simple manner by adjusting the lock. At the same time, the length of the suction section 25 is also changed, so that the sheets 3 are transported in a defined position and in the correct position from the cross-cutting device 5 to the shingling device 10 .

It is particularly advantageous if the movable barrier is designed to be adjustable together with the lifting unit 11 and/or the entire shingling device 10 in and/or counter to the transport direction X of the sheets 3. For this purpose, a carriage (not shown), a scaffolding or a frame can be provided in which the shingling device 10 and the movable barrier are arranged, the carriage being able to be moved in and/or counter to the transport direction X of the sheets 3 . Thus, the device 1 can easily be set to a new or changed sheet format.

If the suction belt 13 of the shingling device 10 extends over a sufficiently long distance in the transport direction X of the sheets, it can also be provided that only the lifting unit 11 and the movable lock are adjusted together in and/or counter to the transport direction X of the sheets 3.

In 3 another device 1 for forming an imbricated stream 2 of overlapping sheets 3 is shown schematically in a side view. Identical or matching functional units, assemblies, components and other matching features in the Figures 1, 2 and 3 shown device 1 are provided with the same reference numerals. The formation of an imbricated stream 2 of overlapping sheets 3 of paper, foil or cardboard takes place in the in 3 shown embodiment corresponding to the above-described imbricated stream formation in the device 1 1 .

Deviating from the device 1 from 2 is the braking device 17 in and/or counter to the transport direction X of the sheets 3 according to the double arrow 21 designed to be displaceable or adjustable in order to be able to adapt the device 1 to a changed sheet format. The scale device 10 is in 3 shown device 1 fixed in position and thus not in and / or opposite to the transport direction X of the sheets 3 adjustable.

The intake section 24 is in accordance with 3 formed by at least one telescoping suction profile, which consists of telescoping suction profile sections 26 and 27 and is connected to a suction device. The suction profile section 27 is preferably arranged in a stationary manner and the suction profile section 26 is preferably designed to be displaceable in and/or counter to the transport direction X of the sheets 3 . The length of the intake section 24 can also be adapted to the sheet format.

In 4 a further device 1 for forming an imbricated stream 2 of overlapping sheets 3 is shown schematically in a side view. Identical or matching functional units, assemblies, components and other matching features in the Figures 1, 2 , 3 and 4 shown device 1 are provided with the same reference numerals. The formation of an imbricated stream 2 of overlapping sheets 3 of paper, foil or cardboard takes place in the in 2 shown embodiment corresponding to the above-described imbricated stream formation in the device 1 1 .

In the 4 shown embodiment of the device 1 differs from that in 3 shown embodiment of the device 1 to the effect that the suction section 24 is formed from at least 2 suction profiles 28 and 29 that mesh with one another and that can overlap at least in sections transversely to the transport direction X of the sheets 3 . The suction profiles 28, 29 are in turn connected to at least one suction device. Crosswise to the direction of transport X of the sheets 3, the combing suction profiles 28, 29 can be formed in an alternating manner.

If the rear edge of the suction profile 29 is level with the front edge of the suction profile 28, the maximum length of the suction section 24 has been reached. If the suction profiles 28, 29 are pushed into one another so as to mesh, for example the suction profile 28 counter to the transport direction X of the sheets, the length of the suction path 24 is reduced.

Reference list:

1

contraption

2

arc current

3

arc

4

tape

5

cross cutting device

6

Wave

7

cutting edge

8th

cutting edge

9

conveyor belt

10

shed facility

11

lifting unit

12

delay unit

13

suction belt

14

suction box

15

racket shaft

16

bat

17

braking device

18

nip roller

19

conveyor belt

20

suction box

21

double arrow

22

suction profile

23

Section

24

suction line

25

suction line

26

suction profile section

27

suction profile section

28

suction profile

29

suction profile

X

transport direction

Y

transport level

Claims (8)

Device (1), in particular a roll cross cutter, for forming an imbricated stream of sheets (3) that overlap or overlap, in particular sheets of paper or cardboard, with a transport device for transporting the sheets, with a shingling device (10) for overlapping or overlapping the Sheets (3), with a braking device (17) following the shingling device (10) in the transport direction (X) of the sheets (3) for braking shingled sheets (3), in particular by forming a braking gap for the passage of sheets (3 ), and with a transverse cutting device (5) upstream of the shingling device (10) for cutting a material strip into individual sheets (3), with a suction section (24) between the shingling device (10) and the braking device (17) for sucking in and further transporting an im imbricated flow of following sheet (3) into the braking device (17), characterized in that a further suction section (25 ) is provided between the cross-cutting device (5) and the shingling device (10), with the intake path (24) between the overlapping device (10) and the braking device (17) and the further intake path (25) being interrupted in the area of the overlapping device (10). . Device (1) according to Claim 1, characterized in that the pressure level in the area of the intake section (24) between the overlap device (10) and the braking device (17) is lowered less than in the area of the further intake section (25). Device (1) according to Claim 1 or 2, characterized in that the shingling device (10) is designed to be adjustable in and/or counter to the transport direction of the sheets (3) as a function of the cut length. Device (1) according to one of the preceding claims, characterized in that the transport device has at least one suction belt (9), in particular a belt arrangement with a plurality of suction belts (9) running parallel to one another, the suction belt (9) moving in the transport direction of the sheets (3) is guided continuously over both intake sections (24, 25) and the area of the overlap device (10). Device (1) according to one of the preceding claims, characterized in that at least one suction device is provided to form a suction section (24, 25), the suction device having a suction profile (22, 28, 29) or a suction box and/or being connected thereto is. Device (1) according to one of the preceding claims, characterized in that at least one continuous suction profile (22), in particular an arrangement of several suction profiles (22) lying one behind the other transversely to the transport direction of the sheets (3), or a continuous suction box for reducing the pressure and forming the Intake section (24) is provided between the overlap device and the braking device (17) and to form the further intake section (25). Device (1) according to one of the preceding claims, characterized in that over the length of the suction profile (22) or suction box there is a discontinuous reduction in the pressure drop in the region of the overlapping device (10), with the suction profile (22) preferably or the suction box has a barrier that can be moved in and/or counter to the direction of transport to form a non-continuous reduction in the pressure drop and wherein, more preferably, the movable barrier together with the overlapping device (10) can be moved in and/or counter to the direction of transport of the sheets (3 ) is adjustable. Method for forming an imbricated stream (2) of sheets (3) that overlap or fall below, in particular sheets of paper or cardboard, more particularly for forming an imbricated stream (2) of individual sheets cut from a strip of material (4) with a cross-cutting device (5). (3), wherein individual sheets (3) are transported to a shingling device (10) and overlapped or undercut in certain areas in order to produce a shingled stream (2), the shingled sheets (3) being transported with one of the shingling devices (10) in the direction of transport (X) the braking device (17) following the sheets (3) are braked, carried out with a device (1) according to one of the preceding claims, characterized in that the following sheets (3) of an imbricated stream are subjected to the effect of suction in the braking device ( 17) to be transported.

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