Device and method for positionally defined transport of sheets

Abstract

A device (1), in particular a roller cross cutter, for forming a shingle stream of overlapping or overlapping sheets (3), especially paper or cardboard sheets, is shown and described. The device comprises a transport unit for transporting sheets, a shingle unit (10) for selectively overlapping or underlapping the sheets (3), a braking unit (17) following the shingle unit in the transport direction (X) of the sheets (3) for braking shingle sheets (3), in particular by forming a braking gap for the passage of shingle-matched sheets (3), and a cross-cutting unit (5) upstream of the shingle unit (10) for cutting a strip of material into individual sheets (3). According to the invention, a suction section (24, 25) is provided between the shingle unit (10) and the braking unit (17) for drawing in and transporting a sheet (3) trailing in the shingle stream into the braking unit (17).

Description

[0001] The invention relates to a device, in particular a so-called roller cross cutter, for forming a shingled stream of overlapping sheets, especially of paper or cardboard sheets, comprising a transport device for transporting sheets, a shingling device for partially overlapping the sheets, 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 shingled, joined sheets, and a cross-cutting device upstream of the shingling device for cutting a strip of material into individual sheets, each according to the preamble of claims 1 and 2.Furthermore, the invention relates to a method for forming a shingle stream of overlapping sheets, in particular sheets of foil, paper or cardboard, and further in particular for forming a shingle stream of individual sheets cut from a strip of material with a cross cutter, wherein individual sheets are transported to a shingle device and partially overlapped to generate a shingle stream, and wherein the shingled sheets are braked by a braking device following the shingle device in the transport direction of the sheets.

[0002] A roll-to-roll cross-cutter is known, for example, from DE 101 03 040 A1. With this known roll-to-roll cross-cutter, sheets of paper or cardboard can be supplied as a virtually endless roll. A feeder with rollers or cylinders feeds the roll to a cross-cutting unit, where it is cut into sheets of a defined length. Often, a paper buffer is installed upstream of the feeder to maintain a specific web length of paper. The cut sheets are then conveyed by high-speed conveyor belts to a raking unit to create an overlap. The raking unit comprises a lifting shaft and a suction belt positioned above it. As the sheets pass through the raking unit, they are lifted at a defined point, particularly at the trailing edge, relative to the conveyor plane by the lifting shaft and pressed against the suction belt above.The suction belt has a lower rotational speed than the fast-running conveyor belts that transport the sheets from the cross-cutting unit. The sheet is thus slowed down when its trailing edge is pressed against the suction belt above it by the lifting shaft and held there. The shing device acts as the first, rear braking unit.

[0003] A braking device is arranged downstream of the shingling unit in the transport direction of the shingle stream, serving as a second, front braking unit. Such a braking device is described, for example, in DE 38 12 685 A1. The braking device can have at least one so-called nip roller, which, together with a conveyor belt, another roller, or a cylinder, forms a braking gap. The distance between the braking device and the shingling unit is adjusted such that the leading edge of a sheet preferably enters the braking gap of the braking device and is decelerated when the rear section of the sheet, in particular the trailing edge, is pressed against the suction belt by the lifting shaft of the shingling unit. In this way, the sheet is preferably braked or decelerated simultaneously by the nip roller in the leading section of the sheet and by the suction belt of the shingling unit in the trailing section.Simultaneous deceleration of the sheet at its leading and trailing edges prevents the sheet from waviness during braking. The trailing sheet has a higher speed than the already lifted, leading sheet. Since the leading sheet is held up by its trailing edge on the suction belt, the leading edge of the trailing sheet can be fed underneath the leading sheet. This results in an overlap of the sheets due to the speed difference between the leading and trailing sheets. In this way, a continuous stream of overlapping sheets is generated. Following the braking device, the overlapping sheet stream is conveyed at the same speed and with the same overlapping sheet length onto a transfer table with slow-running conveyor belts to a downstream processing machine.

[0004] As described in the previous paragraph, the sheets are braked at approximately the same time at their leading and trailing edges. Particularly with long sheet formats, sagging can occur, whereby a sagging leading sheet can impede the forward movement of a following sheet. This can lead to problems with the positioning accuracy of the trailing sheets at the braking gap. To prevent sagging, in the underlap process described above, the sheets are drawn in by the suction belt after being pushed upwards by the beater shaft, held in place, and thereby tightened or tensioned.

[0005] Sheet tension is achieved by setting the speed of the suction belt slightly lower than the speed of the brake's nip rollers. The tensile forces exerted on the sheet by the speed difference between the nip rollers and the suction belt tension the sheet and reduce sagging. When the leading sheet is conveyed out of the suction belt's engagement zone, it is no longer held by the belt. A falling sheet would obstruct the leading edge of the trailing sheet to such an extent that a position-defined undercut would no longer be possible. Due to the increased friction caused by the leading sheet's own weight, the faster-moving following sheet would be hindered in its forward motion. For this reason, a sheet with its trailing edge folded upwards remains within the suction belt's engagement zone for longer than one cycle.A cycle refers to the time interval between the lifting of a first advancing sheet and the lifting of a second trailing sheet. This ensures that when the advancing sheet leaves the suction belt's reach, it is held aloft by a trailing sheet that has already been lifted and is being suctioned, since the trailing edge of the trailing sheet is then already within the suction belt's reach, and the trailing sheet holds the advancing sheet aloft. The suction belt must therefore provide sufficiently high suction power to securely hold both the lifted sheets and the sheets held by them.

[0006] As the sheet length increases, so does the weight of the leading sheet, which must be supported by the trailing sheet. This increases the risk of sheet sagging, especially with larger sheet sizes. Furthermore, despite the speed difference between the slow-running conveyor belts and the suction belt of the shingle unit that guides the sheet's trailing edge, it is not possible to completely prevent sheet sagging. For this reason, particularly with long sheet sizes, the leading sheets sag more significantly, which can create a braking effect on the leading edge of the following sheet through frictional contact. This negatively affects the positioning and orientation of the trailing sheet. A misaligned or suboptimally positioned sheet in the shingle flow can lead to positioning errors, damage to the sheet, or even a complete system shutdown.

[0007] EP 0 503 531 A1 discloses a device for forming a shingle stream with a holding device arranged above a belt assembly. The belt assembly has a plurality of suction belts, each associated with a suction channel. The high profile is provided with a continuous suction opening in the region of its upper wall.

[0008] The object of the present invention is to provide a device and a method of the type mentioned above, which enable a precise or defined entry of a trailing arc into the braking device within the arc stream. Furthermore, damage caused by an imprecise entry of the arcs into the braking device should be reliably prevented, even at high transport speeds.

[0009] The aforementioned problem is solved according to the invention in a device of the type mentioned at the outset by the features of claim 1 and claim 2 and by a method with the features of claim 6.

[0010] According to the invention, a suction section, preferably formed below the transport plane of the sheets, is provided in the area between the shearing device and the braking device for transporting the leading edge of a sheet trailing in the shear stream into the braking device. Accordingly, in the method according to the invention, the trailing sheets of a shear stream are transported into the braking device, preferably from below, by means of suction.

[0011] The invention is based on the fundamental idea of ​​guiding the leading edges of the following arches to the braking device in a defined manner by means of a suction in the area between the shingle device and the braking device. The leading edge of a trailing arch is thereby moved at least section by section relative to a leading arch, whereby, in the case of under-shingle operation, the leading edge of the arch is drawn in from below and is located below a leading arch.

[0012] This significantly increases the positional accuracy of the leading edge and thus of the entire arc. The invention also prevents damage to the arc at the braking point, which can be caused by positional inaccuracies of the leading edge.

[0013] The intake path is formed, for example, in the case of underscaling by generating a negative pressure below the transport plane of the bows.

[0014] To form a suction section, at least one suction device is provided. For example, the suction device can interact with at least one suction belt that moves in the transport direction and serves to transport the sheets further after they have passed the shingle device. The negative pressure generated by the suction device is designed such that at least the leading edge or a portion of the leading edge of a sheet is held in place so that the sheet is transported in a desired position with precise positioning.

[0015] Preferably, the suction section is formed by a plurality of suction belts arranged one behind the other transversely to the transport direction and running parallel to each other. The sheets are drawn in and transported via the suction belts. Each suction belt can have its own suction device. However, it is also possible to have only a single suction device, for example, a suction box, which generates a vacuum for all suction belts. Alternatively, the suction section can be formed by several conveyor belts arranged one behind the other transversely to the transport direction and running parallel to each other, in which case no vacuum is generated via the conveyor belts. In this embodiment, suction zones can be provided between the conveyor belts to generate the vacuum.The suction device is designed to create 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.

[0016] A sheet whose leading edge enters the suction area is drawn in, at least in the area of ​​the leading edge, and thus transported in a defined position in the direction of sheet transport. The leading edge of the sheet is fixed to at least one suction belt or conveyor belt in such a way that the leading edge of the sheet does not detach during transport. For this reason, the leading edge of the sheet can be transported into a braking gap of the braking device without damage. In the case of undercutting, the trailing edge of the sheet can be pressed against a suction belt of the undercutting device by a beater shaft of the undercutting device simultaneously with the entry of the leading edge into the braking device. The trailing edge of the sheet is then held up by the suction belt of the undercutting device and simultaneously braked in the area of ​​the leading and trailing edges of the sheet.The trailing sheet can remain on the high-speed transport device, with at least the area of ​​its leading edge entering the intake section. The trailing sheet is conveyed at a higher speed relative to the leading sheet, maintaining a defined position in the transport direction below the leading sheet towards the braking device. This prevents the leading edge of the sheet from detaching from the intake section. The trailing sheet can thus be conveyed below the leading sheet to the braking device without interference or collision. This achieves a subdivision of the sheet flow.

[0017] An additional intake section is provided between the cross cutter and the shing unit. The intake section between the shing unit and the braking unit, as well as the additional intake section, are designed using either the same intake unit or several separate intake units. This additional intake section serves to transport the sheets from the cross cutter to the shing unit in a defined manner and in a desired position. This ensures high positional accuracy of the sheets, which is necessary because both the cross cutter and the shing unit must operate in sync with the downstream processing machine. Due to this synchronization, it is crucial that the leading edge of the sheet occupies a defined position at all times. This positional accuracy, of course, applies to the entire sheet.

[0018] Furthermore, the intake path between the scutting mechanism and the braking mechanism, as well as the subsequent intake path in the area of ​​the scutting mechanism, are interrupted. Between this interrupted intake path and the subsequent intake path, there is a zone in the transport plane of the bows where no negative pressure, or a significantly reduced negative pressure, is generated. This is particularly advantageous when the trailing edge of the bow is lifted by means of a beater shaft. This facilitates the lifting of the trailing edge of a bow, as no or a significantly reduced suction force acts on the trailing edge during this process.The suction section is designed such that the sheet is drawn in, at least in the area of ​​its leading edge, and conveyed in a defined position in the transport direction, while and after the trailing edge of the sheet is gripped by the beater shaft and pressed against the suction belt of the scutting unit above it. Since no or significantly reduced suction force acts on the sheet in the area of ​​the beater shaft of the scutting unit, the stresses experienced by the sheet during its upward stroke are reduced. A high suction force on the trailing edge of a sheet during its upward stroke could cause the sheet to be damaged or to slip out of its defined position.

[0019] Advantageously, the pressure level in the intake section between the shingle of the braking device is less reduced than in the further intake section between the cross cutter and the shingle. "Less reduced" in this context means that the pressure difference between the vacuum generated in the intake section between the shingle and the braking device and the ambient pressure is less pronounced than in the further intake section. This results in the sheet being pulled in with a high force in the section between the cross cutter and the shingle to achieve high positional accuracy. In the intake section between the shingle and the braking device, the sheet, or at least its leading edge, is pulled in with less force.The different vacuum levels on both sides of the shingle device enable precise and rapid sheet transport from the cross cutter to the braking device.

[0020] It can be advantageous to have a pressure reduction of less than 2 mbar, preferably less than 1 mbar, more preferably less than 0.5 mbar, and particularly preferably less than 0.1 mbar, relative to ambient pressure in the intake section between the shingling device and the braking device. However, the pressure reduction can also be significantly higher, ranging from 0.5 to 10 mbar, preferably between 1 and 5 mbar, and particularly down to 2 mbar, relative to ambient pressure. A pressure reduction advantageously ensures that the leading edge of the sheet, and thus the entire sheet, can be transported in a defined position.

[0021] In a further advantageous manner, the pressure drop in the area of ​​the further intake section, i.e., in the area between the cross cutter and the scaling device, is ten to one hundred times greater than in the area between the scaling device and the braking device. Due to the stronger negative pressure, the sheets are transported with pinpoint accuracy from the cross cutter to the scaling device.

[0022] In an advantageous embodiment, the shingling device is adjustable in and / or against the transport direction of the sheets, depending on the cutting length. This allows for easy adaptation of the device to a changed sheet format. The term "cutting 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 change in sheet format. In a further advantageous embodiment, the braking device is fixed in and / or against the transport direction of the sheets. Thus, the distance between the transfer point and the braking device is the same for every sheet format, i.e., independent of the cutting length.

[0023] Depending on the current (new) sheet length relative to the braking device, the shing device can then be moved, offset, or shifted in or against the transport direction of the sheets, so that for every adjustable sheet length, a leading sheet is braked approximately simultaneously at the front by the braking device and at the rear by the shing device. In particular, this makes it possible to keep the distance between the transfer point and the braking device, or the transfer length, constant during a format change, whereby the braking device is preferably not adjusted during a format change. Instead, the distance between the braking device, which is preferably stationary, and the shing device is adjusted to the actual sheet length by adjusting the shing device. Thus, the distance between the front transfer point of the sheets to a sheet processing machine and the braking device remains constant.The transfer length is the same for different formats or cutting lengths, which significantly simplifies the adjustment of the device to a different sheet format. In particular, with a constant transfer length, there is no need to change the overlap length of the sheets in the shingle flow when changing formats.

[0024] Furthermore, a defined stop point for the device can be established, which is the same for each sheet format. The overlap length, or shingle ratio, can be kept constant 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 overlap length. When the system stops, the leading sheet is always within the suction belt's range of influence, allowing the following sheet to slide underneath it. During a system stop, a trailing sheet can continue to be transported under the leading sheet. This makes it possible to brake the faster-moving belts less sharply or less quickly than the slower-moving belts, as the overlap length acts as a buffer for the trailing sheet.This significantly reduces the material stress on the high-speed belts and their braking units. Since the risk of an uncontrolled slippage of a sheet is minimized by the reduced braking force, less assistance is required to decelerate the sheets. This further reduces energy consumption during a system stoppage. When restarting the device, the slow-speed belts can be driven slightly ahead of the high-speed belts, thus restoring the correct phase alignment within the device. In this context, phase alignment means that the relative position of the sheets to the beater shaft and the position of the knives on the cross-cutting unit are always fixed relative to each other. Therefore, a system restart is possible quickly and easily.

[0025] Furthermore, stopping the device while the cross-cutting unit is in the middle of a cut can be prevented. Stopping the device while the cross-cutting unit is performing the cut can lead to uncontrolled damage to the sheet and / or the web of material. Therefore, stopping the device during a cut must be avoided. Since the trailing sheet has a shingle length or overlap length as a buffer against the leading, already folded-up sheet, the slow-running conveyor belts and the cross-cutting unit can be stopped in such a targeted manner that the cross-cutting unit stops outside the cutting area.

[0026] The transport device has at least one suction belt, in particular a belt arrangement with several suction belts running parallel to each other, wherein the suction belt is guided continuously in the transport direction of the sheets from the cross cutter to the braking device, i.e., across both suction sections and the area of ​​the shing device. Thus, only one preferably high-speed suction belt or only one belt arrangement extends across the two suction sections and the area of ​​the shing device. This results in easy and simple control. Synchronization of belt sections arranged sequentially in the transport direction is therefore not necessary. Alternatively, separate belt sections are provided to enable sheet transport in the area of ​​the two suction sections.

[0027] At least one suction device is provided to form a suction path, wherein the suction device comprises a suction profile or a suction box. The use of a suction profile or a suction box allows the generated negative pressure to be produced in a targeted and localized manner. A continuous suction profile, in particular an arrangement of several suction profiles positioned one behind the other transversely to the transport direction of the bends, or a continuous suction box is provided for pressure reduction and the formation of the suction path between the shingle device and the braking device, and for the formation of the further suction path. A continuous suction profile from the cross cutter to the braking device allows for simple sealing and adjustment of the negative pressure generation along the profile length in the transport direction of the bends.

[0028] A non-continuous or discontinuous reduction in pressure drop, or a sudden pressure drop, is provided along the length of the suction profile or suction box in the area of ​​the overlapping 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 bends before the overlapping device to a lower negative pressure after the overlapping device. For this purpose, a single, uninterrupted suction profile or a single, uninterrupted or continuous suction box is provided, whereby the negative pressure level in the suction profile or suction box is divided by a barrier or seal. In other words, the length of the suction path can be changed by changing the position of the barrier. The barrier or seal causes a non-continuous change in the pressure drop along the length of the suction profile or suction box.The position of the sudden pressure increase in the suction profile or suction box in the transport direction of the sheets can be easily changed by the movable lock and, in particular, aligned to the position of the shing device when the shing device is adjustable depending on the sheet format.

[0029] In a further preferred embodiment of the invention, the movable stop or seal, together with the shingling device, is adjustable in and / or against the transport direction of the sheets. This combined adjustability is achieved by providing a common carriage for the shingling device and the movable seal or stop, wherein the common carriage is adjustable in and / or against the transport direction of the sheets. When the shingling device is adjusted, the location of the discontinuous pressure change shifts with the position of the shingling device in or against the transport direction of the sheets. This ensures that, at least at the location of the shingling device, the pressure level is always lower than in the area between the cross cutter and the shingling device.

[0030] Alternatively, to form a variable-length intake section between the scraper mechanism and the brake mechanism, at least one telescopic suction profile and / or at least two interlocking suction profiles can be provided. Telescopic and / or interlocking suction profiles represent simple mechanical designs of variable-length intake devices. Telescopic in this case means that several complementary suction profiles can be moved into one another, thus changing the length of the entire suction profile. It must be ensured that the two complementary, interlocking suction profiles are tightly connected, for example, by means of a dynamic seal, so that a substantially uniform pressure profile can be achieved along the length of the suction profile.

[0031] The intake section can also be formed from alternatingly arranged suction profiles, with a first suction profile extending in the transport direction from the scraping device and a second suction profile extending in the opposite direction from the braking device, and the two suction profiles overlapping at least partially transversely to the transport direction. The two suction profiles can be shifted relative to each other in a meshing motion until the leading edge of one suction profile reaches the trailing edge of the other, and vice versa. At this point, the maximum length of the intake section is achieved.

[0032] Both of the above-mentioned methods for creating a variable-length intake section between the shingling device and the braking device also allow for an adjustable arrangement of the braking device relative to the shingling device. If the braking device is to be adjusted in and / or against the transport direction of the sheets, for example, to adapt the device to a changed sheet format, the intake section between the shingling device and the braking device can be easily adjusted to the changed length between the shingling device and the braking device.

[0033] Further features of the present invention will become apparent from the following description of an embodiment of the invention with reference to the drawings and the drawings themselves.

[0034] The invention will be explained in more detail below with reference to the figures; they show Fig. 1 is a schematic representation of a prior art device for forming a shingle stream of overlapping arcs in a side view; Fig. 2 is a schematic representation of a device according to the invention for forming a shingle stream of overlapping arcs in the operating state in a side view; Fig. 3 is a schematic representation of a further embodiment of a device according to the invention for forming a shingle stream of overlapping arcs in the operating state in a side view; and Fig. 4 is a schematic representation of a further embodiment of a device according to the invention for forming a shingle stream of overlapping arcs in the operating state in a side view.

[0035] In Fig. 1Figure 1 schematically depicts a device 1, known from the prior art, for generating an arc stream 2 of overlapping arcs 3 made of paper, film, or cardboard. The device 1 includes a feed unit (not shown) that conveys a virtually endless paper or cardboard strip 4. The strip is supplied from a paper or cardboard roll on a feed side by a dispensing device (not shown) and can be guided through an intermediate paper buffer. A cross-cutting device 5, located downstream of the feed unit (not shown) in the transport direction X of the arcs 3, cuts the strip 4 into arcs 3 of defined length. The cross-cutting device 5 is designed as a rotatably mounted shaft 6, which has a cutting edge 7 on its circumference. When the cutting edge 7 arranged on the shaft 6 and a stationary cutting edge 8 are engaged, the strip 4 is cut.The arc length can be adjusted by changing the rotational speed of shaft 6 and the feed speed.

[0036] The arches 3 are transported in the transport direction X on a conveyor belt system with at least one high-speed conveyor belt 9. Preferably, a conveyor belt system with several conveyor belts 9 is provided, arranged one behind the other transversely to the transport direction X and spaced apart from each other. The following descriptions of the conveyor belt 9 refer to this conveyor belt system.

[0037] A shing device 10 following the cross-cutting device 5 consists of a lifting unit 11 and a deceleration unit 12. The deceleration 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 perforated conveyor belt that interacts with a vacuum-generating suction box 14. 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 moves at a lower speed than the fast-running conveyor belt 9, the leading edge of a trailing sheet 3 is conveyed under the raised trailing edge of a leading sheet 3.With the next rotation of the beater shaft 16, the trailing arc 3 is lifted at its trailing edge, allowing the trailing arc 3 to be conveyed beneath it. In this way, an arc stream 2 of overlapping arcs 3 is generated. Once the trailing edge of the leading arc 3 is no longer within the engagement area of ​​the suction belt 13, the leading arc 3 is held above the transport plane by the trailing arc 3, as the trailing arc 3 is already being held up by the suction belt 13 before the leading arc 3 leaves the engagement area of ​​the suction belt 13.

[0038] Downstream of the shingling device 10, a braking device 17 is provided in the transport direction X of the arc stream 2. The braking device 17 has at least one nipple roller 18, which, together with at least one slow-running conveyor belt 19, forms a braking gap. The distance between the braking device 17 and the shingling device 10 is adjusted such that the leading edge of an arc 3 preferably enters the braking gap and is decelerated when the rear arc section, in particular the trailing edge of the arc 3, is pressed against the suction belt 13 by the beater 16 of the lifting unit 11. In this way, the arc 3 is preferably braked or decelerated approximately simultaneously by the nipple roller 18 and the slow-running conveyor belt 19 in the leading area and by the suction belt 13 in the trailing area.To tension the sheet and reduce sagging, the suction belt 13 operates at a slightly reduced speed compared to the slow-running conveyor belt 19. Following the braking device 17, the sheet stream 2 is transported at the same speed and, in particular, with substantially the same sheet length, i.e., with the same distance from the leading edge of the advancing sheet 3 to the leading edge of the trailing sheet 3, on a transfer table (not shown) to a transfer point (not shown) of a downstream processing machine.

[0039] In the area between the cross-cutting device 5 and the shingling device 10, a suction box 20 can be arranged below the conveyor belt 9. The conveyor belt 9 is then preferably designed as a suction belt. A vacuum is created in the suction box 20, which attracts the sheets against the conveyor belt 9. This transports the sheet 3 or the web of material 4 on the conveyor belt 9 before, during, and after cutting in the cross-cutting device 5.

[0040] As in Fig. 1As can be seen, the braking device 17 is designed to be adjustable in and / or against the transport direction X of the sheets 3. This is indicated by the double arrow 21. If the device 1 is changed to a different sheet format, the braking device 17 is adjusted so that the distance between the braking device 17 and the shing device 10 essentially corresponds to the sheet length of the new sheet format. The distance between the braking device 17 and the shing device 10 should be adjusted such that the sheet 3 is braked essentially simultaneously at its leading edge by the braking device 17 and at its trailing edge by the suction belt 13 of the shing device 10.

[0041] Depending on the current (new) sheet length relative to the braking device 17, the shing device 10 can then be moved, offset, or shifted in or against the transport direction of the sheets 3, so that for each adjustable sheet length, a leading sheet 3 is braked approximately simultaneously at the front by the braking device 17 and at the rear by the shing device 10. In particular, this makes it possible to keep the distance between the transfer point and the braking device 17, or the transfer length, constant during a format change, whereby the braking device 17 is preferably not adjusted during a format change. Instead, the distance between the braking device 17, which is preferably stationary, and the shing device 10 is adjusted to the actual sheet length by adjusting the shing device 10. Thus, the distance between the front transfer point of the sheets 3 to a sheet processing machine and the braking device 17 remains constant.The transfer length is the same for different formats or cutting lengths, which significantly simplifies the adjustment of the device to a different sheet format. In particular, with a constant transfer length, there is no need to change the overlap length of the sheets 3 in the shingle stream when changing formats.

[0042] It has happened in the Fig. 1The illustrated device 1 shows that the transport of the sheet's leading edge between the shingle device 10 and the braking device 17 is prone to malfunctions. The leading edge of the sheet can detach from the rapidly moving conveyor belt 9, particularly at high transport speeds. If the sheet's leading edge 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 displaced from its position by the detachment of its leading edge, resulting in an inaccurate shingle length between the leading edge of the advancing sheet 3 and the leading edge of the trailing sheet 3. In addition, the sheet's leading edge can come into frictional contact with the advancing sheet 3 either when detaching from the rapidly moving conveyor belt 9 or by slipping.This can further slow down arc 3, so that the desired shingle length is also not achieved.

[0043] In Fig. 2 A schematic representation of another device 1 for forming a shingle stream 2 of overlapping arcs 3 is shown in a side view. Identical or corresponding functional units, assemblies, components, and other corresponding features of the devices shown in the diagram are not included. Figures 1 and 2 The devices 1 shown are provided with the same reference numerals. The formation of a shear stream 2 of overlapping sheets 3 made of paper, foil or cardboard occurs during the process described in Fig. 2 the embodiment shown corresponds to the scale flow formation described above in device 1. Fig. 1 .

[0044] In contrast to the one in Fig. 1 The device shown in 1 is, in the embodiment according to Fig. 2It is provided that the shing device 10 is adjustable in and / or against the transport direction X depending on the sheet length or sheet format. This is in Fig. 2schematically shown by the double arrow 21. The braking device 17, on the other hand, is fixed in and / or against the transport direction X of the sheets 3. In other words, this means that when the cutting length of the sheets 3 changes or the sheet format changes, the shing device 10 is offset, shifted, or moved relative to the braking device 17 such that, for every set sheet length, a leading sheet 3 is braked approximately simultaneously at the front by the braking device 17 and at the rear by the deceleration unit 12 of the shing device 10. Thus, the distance between the transfer point of the sheets 3 (not shown) to a downstream machine and the braking device 17, or the transfer length, remains constant for different formats or cutting lengths of the sheets 3, which significantly simplifies the setting of the Fig. 2The device 1 shown is used to change the sheet format. For a format change, the entire shingling device 10 can be adjusted in or against the transport direction X of the sheet flow 2; that is, the lifting unit 11 and the deceleration unit 12 are moved together. These units can be mounted or supported for this purpose in a chassis, frame, or support that can be moved in and / or against the transport direction X of the sheets 3. 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.

[0045] At the in Fig. 2In the illustrated device 1, a suction profile 22 is provided between the shearing device 10 and the braking device 17 below the high-speed conveyor belt 9. This suction profile is designed as a hollow profile and is connected to a suction device (not shown), such as an extraction fan. Preferably, in a conveyor system with a plurality of conveyor belts 9 designed as suction belts, each conveyor belt 9 is assigned a suction profile 22.

[0046] 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 shearing device 10 and the braking device 17, and a further suction section 25 is formed in the area between the shearing device 10 and the cross-cutting device 5. A negative pressure is exerted on the sheets 3 via the suction profile 22 and the conveyor belt 9, at least in the area of ​​the leading edge of the sheets 3. The applied negative pressure prevents the leading edge of a sheet 3 from detaching. Simultaneously, the suction section 24 ensures that the trailing sheet 3 is transported in a defined position after passing the shearing device 10. Thus, a defined shearing of the sheets 3 is possible without the sheets 3 interfering with each other.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 shingle device 10, the suction profile 22 forms the further suction path 25.

[0047] The negative pressure applied to the suction profile 22 should be significantly less strong in the area of ​​the suction section 24 following the shingle device 10 in the transport direction X than the negative pressure applied in the area of ​​the further suction section 25 between the cross-cutting device 5 and the shingle device 10. In the area of ​​the shingle device 10, more precisely in the area of ​​the beater shaft 15 with the beater 16, a section 23 is provided where no negative pressure or a comparatively less strong negative pressure is applied. In this way, the sheet 3 can be easily lifted in area 23 and pressed against the suction belt 13. In the area of ​​the sheet's trailing edge, the lifting unit 11 therefore does not have to counteract a negative pressure that would hold the sheet 3 with its trailing edge on the fast-moving conveyor belt 9.Thus, precise positioning and location of the trailing bow 3 under the raised leading bow 3 is possible, while at the same time the trailing edge of the bow can be pressed against the suction belt 13 by the beater 16 without impairment.

[0048] The suction profile 22 can preferably be formed by a continuous hollow profile. The different vacuum levels in the area of ​​the intake section 24 and the intake section 25 can be achieved by a barrier or seal in the area of ​​the sliding device 10. In this case, it is possible to provide only one vacuum-generating device, which is connected to the suction profile 22 in the area of ​​the intake section 25. A low vacuum is simultaneously generated in the intake section 24 via the barrier. The pressure drop in the area of ​​the intake section 24 compared to the ambient pressure is preferably significantly lower than the pressure drop in the area of ​​the intake section 25.

[0049] It is advantageous if the barrier in the profile forming the intake sections 24, 25 is movable, in particular displaceable, in and / or against the transport direction X of the sheets 3. Thus, the length of the intake section 24 can be easily adjusted to the sheet format by adjusting the barrier. Simultaneously, the length of the intake section 25 is also changed, ensuring that the sheets 3 are transported from the cross-cutting device 5 to the shing device 10 in a defined position and orientation.

[0050] It is particularly advantageous if the movable lock, together with the lifting unit 11 and / or the entire shingle assembly 10, is adjustable in and / or against the transport direction X of the sheets 3. For this purpose, a carriage, frame, or rack (not shown) can be provided in which the shingle assembly 10 and the movable lock are arranged, and the carriage can be moved in and / or against the transport direction X of the sheets 3. Thus, the device 1 can be easily adjusted to a new or changed sheet format.

[0051] Provided that the suction belt 13 of the shingle device 10 extends over a sufficiently long distance in the transport direction X of the arches, it may also be provided that only the lifting unit 11 and the movable lock are adjusted together in and / or against the transport direction X of the arches 3.

[0052] In Fig. 3A schematic representation of another device 1 for forming a shingle stream 2 of overlapping arcs 3 is shown in a side view. Identical or corresponding functional units, assemblies, components, and other corresponding features of the devices shown in the diagram are not included. Fig. 1, 2 and 3 The devices 1 shown are provided with the same reference numerals. The formation of a shear stream 2 of overlapping sheets 3 made of paper, foil or cardboard occurs during the process described in Fig. 3 the embodiment shown corresponds to the scale flow formation described above in device 1. Fig. 1 .

[0053] In contrast to device 1 from Fig. 2 The braking device 17 is designed to be displaceable or adjustable in and / or against the transport direction X of the sheets 3 according to the double arrow 21 in order to adapt the device 1 to a changed sheet format. The shing device 10 is located in the Fig. 3The device shown 1 is fixed in position and therefore cannot be adjusted in and / or against the transport direction X of the arches 3.

[0054] The intake path 24 is designed according to Fig. 3 formed by at least one telescopic suction profile consisting of nested suction profile sections 26 and 27, and connected to a suction device. Preferably, the suction profile section 27 is fixed in position, and the suction profile section 26 is preferably designed to be displaceable in and / or against the transport direction X of the sheets 3. The length of the suction section 24 can thus also be adapted to the sheet format.

[0055] In Fig. 4 A further device 1 for forming a shingle stream 2 of overlapping arcs 3 is shown schematically in a side view. Identical or corresponding functional units, assemblies, components, and other corresponding features of the devices shown in the diagram are not included. Fig. 1, 2 , 3 and 4The devices 1 shown are provided with the same reference numerals. The formation of a shear stream 2 of overlapping sheets 3 made of paper, foil or cardboard occurs during the process described in Fig. 2 the embodiment shown corresponds to the scale flow formation described above in device 1. Fig. 1 .

[0056] The in Fig. 4 The embodiment of device 1 shown differs from the one in Fig. 3 In the illustrated embodiment of the device 1, the suction section 24 is formed from at least two mutually interlocking suction profiles 28 and 29, which can overlap at least partially transversely to the transport direction X of the arcs 3. The suction profiles 28, 29 are in turn connected to at least one suction device. Transversely to the transport direction X of the arcs 3, the interlocking suction profiles 28, 29 can be arranged alternately.

[0057] When the trailing edge of the suction profile 29 is at the same height as the leading edge of the suction profile 28, the maximum length of the suction path 24 is reached. If the suction profiles 28 and 29 are pushed into each other in a meshing motion, for example, the suction profile 28 against the transport direction X of the bends, the length of the suction path 24 is reduced. Reference symbol list:

[0058] 1 Device 2 Arc flow 3 Arc 4 Belt 5 Cross-cutting device 6 Shaft 7 Cutting edge 8 Cutting edge 9 Conveyor belt 10 Shear device 11 Lifting unit 12 Deceleration unit 13 Suction belt 14 Suction box 15 Beater shaft 16 Beater 17 Braking device 18 Nipple roller 19 Conveyor belt 20 Suction box 21 Double arrow 22 Suction profile 23 Section 24 Suction path 25 Suction path 26 Suction profile section 27 Suction profile section 28 Suction profile 29 Suction profile X Transport direction Y Transport level

Claims

1. A device (1), in particular a roller cross-cutter, for forming a shingled stream of underlapping sheets (3), in particular paper or cardboard sheets, which are to be shingled, having a transport device for transporting sheets, having a shingling device (10) for underlapping the sheets (3) in regions, having a braking device (17), which follows 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) which are brought together in a shingled manner, and having a cross-cutting device (5), which is arranged upstream of the shingling device (10), for cutting a material web into individual sheets (3), wherein a suction section (24) is provided between the shingling device (10) and the braking device (17) for sucking in and further transporting a sheet (3), which is trailing in the shingled stream, into the braking device (17), and wherein a further suction section (25) is provided between the cross-cutting device (5) and the shingling device (10), characterized in that at least one continuous suction profile (22) or a continuous suction box is provided for reducing the pressure and for forming the suction section (24) between the shingling device (10) and the braking device (17) and for forming the further suction section (25), wherein a non-continuous reduction of the pressure reduction in the region of the shingling device (10) is provided over the length of the suction profile (22) or suction box, wherein the suction profile (22) or the suction box has a barrier, which is movable in and / or counter to the transport direction, for forming a non-continuous pressure reduction, and wherein the suction section (24) between the shingling device (10) and the braking device (17) and the further suction section (25) are interrupted in the region of the shingling device (10).

2. A device (1), in particular a roller cross-cutter, for forming a shingled stream of underlapping sheets (3), in particular paper or cardboard sheets, which are to be shingled, having a transport device for transporting sheets, having a shingling device (10) for underlapping the sheets (3) in regions, having a braking device (17), which follows 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) which are brought together in a shingled manner, and having a cross-cutting device (5), which is arranged upstream of the shingling device (10), for cutting a material web into individual sheets (3), wherein a suction section (24) is provided between the shingling device (10) and the braking device (17) for sucking in and further transporting a sheet (3), which is trailing in the shingled stream, into the braking device (17), and wherein a further suction section (25) is provided between the cross-cutting device (5) and the shingling device (10), characterized in that the suction sections (24, 25) are formed by a plurality of separate suction devices, wherein the transport device has at least one suction belt (9), which is guided continuously over the two suction sections (24, 25) and the region of the shingling device (10) in the transport direction of the sheets (3), or wherein mutually separate suction belts are provided for the suction section (24) and the further suction section (25) in order to enable the sheet transport in the region of the two suction sections (24, 25), wherein each suction device has a suction profile (26, 27, 28, 29) or a suction box (20), and the suction profile (26, 27, 28, 29) or the suction box (20) is arranged below the suction belt (9), and wherein the suction section (24) is interrupted between the shingling device (10) and the braking device (17) and the further suction section (25) is interrupted in the region of the shingling device (10).

3. The device (1) according to Claim 1, characterized in that the shingling device (10) is designed to be adjustable in and / or counter to the transport direction of the sheets (3) in a manner dependent on the cutting length.

4. The device according to one of the preceding claims, characterized in that the transport device has a belt arrangement having a plurality of suction belts (9) which run parallel to one another.

5. The device (1) according to one of the preceding Claims 1, 3 or 4, characterized in that the movable barrier is designed to be adjustable together with the shingling device (10) in and / or counter to the transport direction of the sheets (3).

6. A method for forming a shingled stream (2) of underlapping sheets (3), in particular paper or cardboard sheets, further in particular for forming a shingled stream (2) of individual sheets (3) which are cut from a material web (4) by a cross-cutting device (5), wherein individual sheets (3) are transported to a shingling device (10) and are underlapped in regions in order to produce a shingled stream (2), wherein the shingled sheets (3) are braked by a braking device (17) which follows the shingling device (10) in the transport direction (X) of the sheets (3), said method being carried out using a device (1) according to one of the preceding claims, characterized in that the trailing sheets (3) of a shingled stream are transported into the braking device (17) under the action of a suction.

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