DE102017012198B9 - Sheet transport device and method for transporting sheets from a sheet guiding cylinder to a sheet conveying system - Google Patents

Abstract

Sheet transport device for a sheet-processing machine, with a sheet transport system (3, 4) that receives a sheet from a sheet-guiding cylinder (2), with a gripping device (3) for clampingly fixing and transporting a respective leading edge of the sheet, and with at least two sheets simultaneously on the lateral surface of the sheet-guiding cylinder (2) holding circulating sheet support segments (6) and pneumatic fixing devices (10) for the trailing edge of the sheet, characterized in that the fixing devices (10) are pneumatically connected to a compressed air generator, the compressed air generator having exactly four fixing devices (10) of a double-sized sprocket shaft (4) in pneumatic flow connection.

Description

The invention relates to a sheet transport device for a sheet processing machine with a sheet from a sheet guiding cylinder receiving sheet conveying system and a method for transporting sheets from a sheet guiding cylinder to a sheet conveying system in a sheet processing machine.

Out of DE 2 025 849 , DE 73 03 778 U and DE 28 13 136 A1 it is known to assign additional sheet-carrying elements to sheet-guiding cylinders that contact the sheets only in certain areas. The disadvantage is that the drums are solid and therefore dynamically unfavorable. Next, the adjustment effort is great.

Out of U.S. 2,965,026A , DE 1 761 714 A , DE 2 002 877 A , DE 25 18 334 B1 and GB 2 256 426 A it is known to form supporting disks of sheet-guiding drums with adjustable contact elements. The disadvantage is that the setting effort is high and cannot be carried out rationally in the case of rapid job changes on sheet-processing machines.

Out of DE 35 35 621 A1 and DE 196 44 011 A1 it is known to displace flat sheet support segments on chains below the periphery of sheet guiding drums. The disadvantage is that these sheet-guiding drums are not suitable for transporting freshly varnished sheets in the delivery of a sheet-processing machine.

Out of DE 10 2004 031 171 A1 and already DE 517 004 A it is known to remove sheets from a cylinder jacket surface by means of suction discs that can be adjusted to pressure-free side edges. The vacuum required to hold the sheet edges is generated by a pump and transmitted to the main sprocket shaft via a rotary valve. The rotary valve takes over the clocking of the suction air. The disadvantage is that this rotary valve usually works without contact and very large amounts of leakage air are drawn. Furthermore, high demands are placed on the rigidity of the assembly, since even the slightest deformation leads to a change in the gap between the rotor and stator, which makes the leakage losses unacceptable or which leads to unwanted contact and thus heavy wear. Due to the desired minimum gap widths in conjunction with the need to exclude contact, high demands are placed on the adjustment during assembly. Although there is the possibility of not designing the rotary slide without contact, this is associated with high wear of the components rubbing against one another, especially in the delivery loaded with powder. A further disadvantage is the fact that the rotary slide and the active point (suction cup) are not directly next to one another, which leads to quite long suction lines that first have to be evacuated for each cycle. Especially with high-speed machines with cycle times of 180 ms and below, these systems threaten to become too sluggish. It is also disadvantageous that the suction disks, due to their design, have to have an axial extent that requires relatively large pressure-free side edges. This reduces the usable sheet area.

Out of DE 10 2005 002 509 A1 , DE 10 2013 224 489 A1 and DE 10 2015 204 113 A1 it is known to press the sheets mechanically or pneumatically against supporting disks of the delivery drum after a transfer center. The disadvantage is that a mechanical or pneumatic support has to be adjusted in a complex manner. A certain axial extent of the support disks is required for a secure hold of the arch.

Out of DE 100 14 417 A1 , DE 10 2004 051 323 A1 , DE 10 2004 052 656 A1 , DE 10 2011 012 808 A1 and DE 10 2004 009 703 A1 it is known to take over sheets from a printing cylinder by means of a delivery drum having supporting discs. The trailing edge of the sheet is held by a traverse that extends over the maximum format width and has suction cups. The disadvantage is that the traverse for taking over the trailing edge of the sheet is large and therefore dynamically unfavorable. The available arc area is reduced by the traverse and high leakage losses occur.

The object of the invention is to provide an alternative sheet transport device and an alternative method for sheet transport. In particular, a sheet transfer from a sheet guiding cylinder to a downstream sheet conveying system is to be further improved.

According to the invention, the object is achieved by a device having the features of the independent device claim and a method having the features of the independent method claim. Advantageous configurations result from the dependent claims, the description and the drawings.

The invention has the advantage of providing an alternative sheet transport apparatus and method for sheet transport. In particular, a sheet transfer from a sheet guiding cylinder to a downstream sheet conveying system is further improved.

A sheet transport device can be used within a sheet-processing machine, for example a sheet-fed printing press, or in a delivery of a sheet-processing machine, for example a sheet-fed printing press. A sheet conveying system can be designed, for example, as a sheet-guiding drum and, in particular, can be arranged between two impression cylinders of a sheet-fed printing press. Accordingly, a sheet-processing machine, in particular a sheet-fed printing machine, with a corresponding sheet transport device is also provided. The sheet conveying system preferably contains a delivery drum, which is used in particular in the delivery of a sheet-processing machine. The delivery drum particularly preferably contains a sprocket shaft, around which gripping devices, in particular gripper carriages of a chain conveyor system, are moved in order to take over leading edges of the sheet.

For example, when printing on sheet-fed presses, small amounts of ink are transferred from the plate to the impression cylinder via the blanket cylinder even in areas that are actually not being printed. In places where no sheet rests on the impression cylinder, these small amounts of ink remain on the impression cylinder, where they can build up over a long period of time. In the case of washing processes, this can also be larger quantities. Sheet support segments that are constantly in contact with the impression cylinder become dirty over time. This also applies to the rear part of the sheet support segments if the maximum format is not being printed. It is therefore advantageous to format the support elements or contact elements that come into contact with a sheet in the area of a sheet-guiding drum or delivery drum.

Suction preferably takes place exclusively at the rear edge of the sheet or at the rear corners. The lateral sheet support segments or support elements can thus be made very narrow, which in turn leads to advantageous, very narrow, non-printing side edges. For example, the sheet support segments in the space between gripper carriages can be designed as brackets or carry brackets around which a traction device, in particular a chain, is guided, which is at least partially equipped with preferably elastic support elements, preferably in such a way that these elements only move in the Area of the lateral sheet edges between gripper carriage and fixing devices, especially suction cups are. When a fixing device, in particular a sucker, is adjusted to the correct arc length, the traction means, in particular the chain, is preferably also adjusted. In this way, the surplus support elements can be advantageously “stored” in an area where they do not come into contact with the sheet when moving to a smaller format length. Advantageously, the support elements are only used at the points where there is still a printing material, in particular paper, between these support elements and the lateral surface of the cylinder. The support elements are thus protected from contamination.

The support elements preferably only contact the printing material and never the soiled printing cylinder surface of a printing cylinder of a sheet-fed printing press. The entire device is therefore much less susceptible to dirt and therefore requires little maintenance. In the case of exclusively supporting sheet support segments, it is particularly preferred to use particularly narrow support elements, it being shown that preferably pneumatic fixing of the sheets at the lateral sheet trailing edges or at the rear corners is sufficient. In particular, the sheet fixed or held from the front edge to the rear edge on the lateral surface of the cylinder can easily be taken over by fixing devices arranged adjacent to the sheet support segments.

In particular, the sheet support segments, in particular support elements, can have the function of pressing the sheet against the sheet guiding cylinder, in particular a pressure cylinder, and thereby preventing the sheet from falling. On the other hand, the sheet can be supported on these sheet support segments, in particular support elements, on its way around the sheet guiding drum or delivery drum, in particular a chain wheel shaft, and can be held on the desired path, for example close to sheet guide plates, so that the sheet cannot describe a secant.

It is particularly preferable for each sheet to be gripped at its rear edge in a transfer center by fixing devices, in particular pneumatic suction cups, which are preferably arranged exclusively in the area of the lateral sheet support segments. The vacuum required for suction is preferably generated "on site" by means of fixing devices working according to the ejector principle. In particular, compressed air is preferably transmitted unclocked via a rotary inlet of a rotatably mounted shaft of the sheet-guiding drum or delivery drum, in particular a rotary inlet of a chain wheel shaft. Near the points of action of the fixing devices, in particular at the corners of the sheet, there is, for example, a solenoid valve each, preferably a quick-acting valve, which is connected to a vacuum ejector via a line that is as short as possible. This sits as close as possible to the teat or is in integrated into the suction cup assembly in order to keep the dead volume to be evacuated as small as possible. This advantageously reduces or avoids leakage losses, which leads to less energy being used (although generating a vacuum using compressed air is actually more energy-intensive than generating it using a pump). Also advantageous are the omission of the complex assembly of the rotary valve and the availability of a practically wear-free solution. A highly dynamic behavior can be achieved by low dead volumes after the solenoid valve in both the pressure and suction lines. Also advantageously, the switching on and/or switching off times can be set or changed as a function of sheet speed and/or printing material, for example via the machine software.

For example, the sheets can be transferred from a rotating sheet guiding cylinder to a revolving gripping device, in particular a gripper carriage, and a sheet conveying system having a delivery drum. The delivery drum of the sheet conveying system preferably has sheet support segments which are arranged adjacent to the sheet guiding cylinder and are driven in a revolving, in particular rotating, manner, which in particular have recesses for the gripper carriages. The sheet support segments form a transfer center with the cylinder surface of the upstream sheet guiding cylinder, in which the gripper carriages take over the sheet leading edges in the gripper circuit of gripper systems of the sheet guiding cylinder. The sheet support segments have, in particular, a small axial extension compared to the cylinder width. Pneumatic means can also be provided, which press the sheets onto the lateral surface of the cylinder and/or which hold the sheets on the sheet support segments or press them against the sheet support segments after the central transfer station.

For example, the sheets can be pressed simultaneously by exactly two sheet support segments in the transfer center against the outer surface of the upstream sheet guiding cylinder. Below the sheet support segments, a sheet guide element can be arranged, which preferably extends far into the area of the transfer centers with a comb element, support blow holes preferably being arranged in the sheet guide element. The support blow holes can preferably be arranged in the central area of the sheet guiding element across the machine width in a high density and in the adjacent areas, in particular in the upstream and/or downstream areas in the sheet conveying direction, in a lower density compared to the central area. The blown air of the sheet guiding element could also be varied or clocked or controlled or regulated according to sensor values according to the progress of the sheet transfer. A sheet transport from a sheet guiding cylinder of a last unit to a sheet conveying system in the delivery of a sheet processing machine can particularly preferably be provided, with a sheet guiding element being able to be provided below the delivery drum.

• 1: Auslage einer bogenverarbeitenden Maschine mit einer Kettenradwelle;
• 2: Perspektivische Darstellung der Kettenradwelle mit verstellbaren Bogenstützsegmenten;
• 3: Perspektivische Darstellung der Kettenradwelle mit Stützelemente tragenden Bogenstützsegmenten und Fixiereinrichtungen für die Bogenhinterkante;
• 4: Seitliche Ansicht der doppeltgroßen Kettenradwelle mit an Ketten angeordneten Andrückelementen;
• 5: Vergrößerte Ansicht eines Bogenstützsegmentes mit Andrückelementen und einem Sauger für die Bogenhinterkante;
• 6: Ausführung eines Andrückelementes für eine auf einem Bügel geführte Kette;
• 7: Ausführung eines Kontaktelementes als Sauger für eine Fixiereinrichtung.

The invention is to be explained below by way of example. The associated drawings show the following schematically:

• 1 : Delivery of a sheet-processing machine with a sprocket shaft;
• 2 : Perspective view of sprocket shaft with adjustable arch support segments;
• 3 : Perspective view of the sprocket shaft with sheet support segments carrying support elements and fixing devices for the sheet trailing edge;
• 4 : Lateral view of the double-sized sprocket shaft with pressing elements arranged on chains;
• 5 : Enlarged view of a sheet support segment with pressing elements and a sucker for the trailing edge of the sheet;
• 6 : Execution of a pressing element for a chain guided on a bracket;
• 7 : Execution of a contact element as a suction cup for a fixing device.

the 1 shows, for example, a delivery 1 of a sheet-processing machine, here in particular a sheet-fed printing press, especially a sheet-fed offset rotary printing press, preferably in aggregate and in-line construction. Accordingly, the machine is preferably operated in the offset process, although other printing processes, such as e.g. B. screen printing, can be integrated into the machine. In the units of the machine that are not shown in more detail, the sheets are gripped by gripper systems from rotating cylinders at the front edge and transferred between the cylinders in the gripper closure. In printing units, the sheets are inked in a printing nip formed by a cylinder and a blanket cylinder, each with a printing color appropriate to the motif. Furthermore, one or more coating units can be provided in which the sheets can be coated by a coating forme cylinder. The cylinders arranged in the machine can be designed as single or multiple sizes, with a single-size cylinder being able to accommodate at least one sheet and a double-size cylinder at least two sheets of maximum format on the circumference. The machine is preferably a turning device for turning the sheets in one Assigned recto and verso printing mode while the machine is running. Next, finishing facilities or finishing plants, such. B. cold foil plants, be integrated in the machine.

In particular, the machine has a drive train of wheels which particularly preferably drives at least the sheet-guiding cylinders of the machine as a continuous drive train of wheels. Sheet guiding cylinders designed as transfer drums or transfer cylinders are preferably also driven by the drive wheel train. For this purpose, the sheet guiding cylinders on the drive side of the machine each have meshing gears that form the drive gear train. The drive wheel train is driven by at least one main drive motor, which drives the drive wheel train at at least one input point. Blanket cylinders of the printing units are also preferably driven by the drive train of wheels. Other rotary bodies or rollers of the machine or the printing units can also be driven at least temporarily by the drive wheel train, and these can also be designed to be coupled to the drive wheel train.

Plate cylinders of printing units can also be assigned individual drives, in particular direct drives. Direct drives are in particular individual drives, the rotors of which are aligned and preferably mounted concentrically directly to the associated cylinders. During printing, the plate cylinder in question is then tracked in an electronically synchronized manner to the blanket cylinder, which is preferably driven by the main drive motor via the drive train of wheels. For this purpose, a rotary encoder can be assigned to the plate cylinder and/or blanket cylinder, which can be connected to a control unit of the printing unit and/or the machine controller. Alternatively, the plate cylinder or cylinders can also be driven via the drive train of wheels from the main drive motor.

The current machine angle is preferably known to a control device of the machine, for example the machine control. The machine angle can be defined as the position of a cylinder in space. For example, the machine angle can be derived or recorded from the main drive motor. Alternatively or additionally, a rotary encoder, in particular a rotary angle encoder, can also be assigned to a preferably rotating element of the machine, which rotary encoder signals feeds or makes available to the control device, in particular the machine controller. For example, a rotary encoder, preferably designed as a rotary encoder, can be assigned to a sheet guiding cylinder of the machine, in particular a sheet guiding cylinder after a turning device (not shown) and/or a sheet guiding cylinder of a last work. In particular, the rotary encoder can be assigned to the last sheet guiding cylinder of the machine arranged directly in front of the delivery 1 and/or connected to the control device and/or to a quality control device, for example an inspection system.

From a sheet-processing machine, for example a sheet-fed printing press, a last double-sized sheet guiding cylinder and a sheet from this sheet conveying system of delivery 1 are shown. The sheet guiding cylinder has an at least approximately closed cylinder jacket surface and is here in particular a printing cylinder 2 of a last printing unit. Alternatively, the sheet guiding cylinder can also be a last cylinder in a coating or other processing plant. The pressure cylinder 2 is double-sized here and contains two diametrically arranged gripper systems lying in gripper channels. The leading edges of the sheet are clamped and thus fixed by these gripper systems for sheet transport. Alternatively, the sheet guiding cylinder can also be single, triple or multiple in size.

In the delivery 1, the sheet conveyor system is also arranged, which in particular has continuously revolving driven and guided gripping devices for taking over and transporting the sheets. The gripping devices are preferably arranged on traction means and are driven in an endless revolving manner via wheels and/or on deflection guides. The gripping devices are in particular arranged parallel to one another and spaced evenly between the traction means and are preferably designed as clamping grippers. The sheet conveying system here has in particular a chain conveying system 3 with revolving gripper carriages and a chain wheel shaft 4 assigned adjacent to the sheet guiding cylinder, in particular the printing cylinder 2 . The chain conveyor system 3 contains here in particular on both sides of the frame of the display 1 on chain guide rails guided guide chains to which and between which the gripper carriages are attached. Each gripper carriage contains a clamping gripper system which, for example, has grippers fixedly arranged on a movable gripper shaft and fixed gripper pads. By twisting the gripper shaft, a gripping movement for fixing a respective leading edge of the sheet can be controlled. Preferably via roller levers and cam rollers, the gripper shaft of a gripper carriage can be actuated by cams, particularly in the area of sheet transfer and in the area of sheet deposit.

The sheets are taken over by the sheet guiding cylinder, in particular impression cylinder 2, from the gripper carriage of the chain conveyor system 3 and guided to a delivery pile 5 along a sheet conveying path in the sheet conveying direction BFR. Preferably via the roller levers and cam rollers, the gripping movements of the gripper carriages can be controlled by cams, particularly in the area of sheet transfer in the central transfer station to the sheet guiding cylinder, in particular impression cylinder 2, and in the area of sheet delivery, particularly above delivery pile 5. Sheets are particularly preferably transported in the delivery 1 exclusively at the leading edge of the sheet by the gripping devices, in particular the gripper carriages. On the sheet conveying path from the sheet guiding cylinder, in particular impression cylinder 2, to the delivery pile 5, the sheets are preferably guided on guide elements (not shown), for example sheet guide plates, and an air cushion can also be formed between the sheet and the sheet guide plates. Contact-free sheet transport can take place particularly in the recto and verso printing mode. For example, one or more dryers and/or dusting devices can be provided on the sheet conveying path.

In the delivery 1, a sheet brake is preferably arranged upstream of the delivery stack 5 in the sheet conveying direction BFR, which takes over the sheets to be deposited from the gripper carriage and decelerates them from machine speed to delivery speed after they have been released. After being decelerated by the sheet brake, the sheets are aligned on front edge stops, rear edge stops and/or side edge stops (not shown) and are neatly placed on the delivery pile 5 . The delivery stack 5 is preferably lowered by a stack lifting drive (not shown) during the sheet deposit process in such a way that the delivery stack surface forms an at least approximately constant deposit level for the coming sheets. The sheet brake can, for example, contain at least two braking stations, which are preferably arranged to be displaceable, in particular displaceable, axially, ie transversely to the sheet conveying direction BFR. The braking stations are placed in particular on a respective lateral edge of the sheet, which is usually unprinted. If further braking stations are planned, these can be placed in pressure-free corridors and/or in sufficiently dried color areas. Braking stations that are not required can be deactivated and/or moved out of the sheet format area. Alternatively, follow-on grippers can also be used.

the 2 shows a perspective view of the sprocket shaft 4, which is associated immediately adjacent to the last sheet guiding cylinder of the machine. The sprocket shaft 4 has a shaft which is arranged parallel to the axis of rotation of the adjacent sheet guiding cylinder and to which sprockets for the circulating chains of the chain conveyor system 3 are assigned on both sides. The sprockets interact with the respective chain guide rails to guide the gripper carriage in the area of the sprocket shaft 4 . The chain wheels are thus coaxial and spaced apart from one another, in particular firmly assigned to the chain wheel shaft 4 . The sprocket shaft 4 is assigned a drive which drives the sprocket shaft 4 in rotation about its axis of rotation synchronously with the drive wheel train. The sprocket shaft 4 here preferably carries a helical gear wheel which interacts with the drive of the machine or is driven by it. The helical gear wheel, which is in particular permanently assigned to the sprocket shaft 4, is preferably part of the continuous drive wheel train or gear train of the machine in meshing engagement with a gear wheel of the sheet guiding cylinder arranged immediately upstream, in particular the impression cylinder 2. A gripper carriage of the chain conveyor system 3 guided in the area of the sprocket shaft 4 picks up a sheet in a common transfer center by gripper closure of a gripper system of the upstream sheet guiding cylinder, in particular the impression cylinder 2.

Between the two chain wheels, the sprocket shaft 4 has at least two and preferably exactly two sheet support segments 6 for simultaneously supporting a sheet against the cylinder surface of the sheet guiding cylinder, in particular the impression cylinder 2. At least one, and preferably both, arch support segments 6 are mounted on a hub, for example, so as to be axially displaceable with respect to the sprocket shaft 4 . In the double-sized version of the sprocket shaft 4, for example, each hub has exactly two arch support segments 6, which are arranged diametrically opposite one another and are firmly associated with the hub. Because the arch support segments 6 are mounted together on a hub that can be displaced axially with respect to the shaft of the sprocket shaft 4, the arch support segments 6 on the respective side are adjusted together. The hub can, for example, have rollers rolling on the surface of the shaft. In this case, provision can be made for assigning six rollers, for example, to each hub, which rollers run on preferably ground tracks of the sprocket shaft 4 . In particular, an adjusting means is provided for the axial adjustment of the sheet support segments 6 . A drive, for example an electrically operated drive motor, is preferably provided for one or for each hub, for example on the operating side, which preferably acts on the respective hub via a spindle drive and performs an axial adjustment of the Hub or the hub associated arch support segments 6 causes. For example, the axial adjustment of the sheet support segments 6 can be carried out together with the axial adjustment of the brake stations of the sheet brake on the sheet format. The axial adjustment can also be carried out and/or monitored automatically on the basis of the same data by a control device, in particular the machine control.

The sheet support segments 6 can preferably be moved apart far enough that sheets of the maximum format to be processed can be supported on the respective lateral sheet side edges. Provision can also be made to move one or both sheet support segments 6 outside of the maximum sheet format, for example to enable sheet transport without sheet support segments 6 or for maintenance. The sheet support segments 6 or hubs can also be axially adjustable or displaceable independently of one another or be adjusted or displaced. For this purpose, the drive motors for the axial adjustment of the hubs carrying the sheet support segments 6 can be controlled independently, for example, by the control device, in particular the machine control. For the circulating gripper carriage of the chain conveyor system 3, the sheet support segments 6 have recesses or their circumferential extent is dimensioned accordingly.

For example, each arch support segment 6 has a bracket 6 which is preferably held in a separate plane. A traction means carrying support elements, in particular a chain 8 carrying pressing elements 7 , is assigned to the bracket 6 on the peripheral side. The bracket 6 contains a guide oriented in the circumferential direction for the traction means, in particular the chain 8, which can thus be shifted or shifted in the circumferential direction or in and/or counter to the sheet conveying direction BFR relative to the bracket 6. The support elements assigned to the traction means, in particular the pressing elements 7 assigned to the chain 8 , are correspondingly mounted so that they can be displaced together in the circumferential direction along the bracket 6 or the guide of the bracket 6 when the traction means or chain 8 is displaced. This means that the support elements, in particular pressing elements 7, can be displaced together in and/or counter to the sheet conveying direction BFR for setting, in particular for format setting.

The support elements, in particular pressing elements 7, associated with the traction means, in particular the chain 8, have an arcuate contact surface with a minimal axial extent. The axial extent of an arcuate contact surface can be, for example, 0.5 mm to 3 mm, preferably at least approximately 1 mm. The support elements, in particular pressing elements 7, preferably contain elastic material or are made of elastic material. The pressing elements 7 can in particular contain rubber or be made of rubber. For example, the support elements, in particular pressing elements 7, can also have a wedge-shaped cross section or a raised sheet contact surface, viewed in the sheet conveying direction BFR. In the circumferential direction or along the sheet conveying direction BFR, the extent of the pressing elements 7 can be up to 50 mm, for example. Through a contact line of the support elements, in particular the sheet contact surfaces of the pressing elements 7, a sheet can be pressed against the lateral surface of the sheet guiding cylinder, in particular the impression cylinder 2, and thus can be fixed or held on it. A sheet fall is thus avoided as long as the sheet is between the support elements, in particular pressing elements 7, and the sheet guiding cylinder, in particular impression cylinder 2. A sheet is preferably pressed against the lateral surface of the cylinder exclusively by the support elements, in particular pressing elements 7, and not sucked in by sheet support segments 6.

A hub of the sprocket shaft 4 that carries, for example, two arch support segments 6 in each case also has, in particular, a hub sleeve that can be moved in the circumferential direction and that is preferably mounted on the hub so that it can rotate. A separate drive is preferably assigned to the hub shell, which can displace the hub shell relative to the hub in the circumferential direction or in and/or counter to the sheet conveying direction BFR. The drive can, for example, be arranged directly on the hub or hub shell and shift the hub shell relative to the hub. The hub can, for example, have an internally toothed toothed segment, in which a pinion driven by the drive engages. The hub sleeve or the drive is correspondingly displaced axially along the shaft of the sprocket shaft 4 with the hub. Energy and/or signals are preferably transmitted to the drive located on the hub by means of a rotary inlet 11 of the rotatably mounted sprocket shaft 4. For example, cables are routed in the interior of the sprocket shaft 4 up to approximately the center of the machine, where a trailing cable is provided for storing the cable is. The two drives, each assigned to a hub, are supplied from the cable drag.

A sprocket shaft 4 and in particular a respective hub sleeve is preferably assigned at least one fixing device for preferably pneumatically fixing a trailing edge of a sheet in certain areas. In the double-size version tion of the sprocket shaft 4, each hub sleeve carries exactly two fixing devices which are arranged diametrically opposite one another and which are preferably each firmly connected to the hub sleeve. By means of a drive that displaces a respective hub sleeve relative to the hub, the fixing devices can be placed on the respective trailing edge of the sheet in and/or counter to the sheet conveying direction BFR. The drive particularly preferably simultaneously moves the traction means assigned to the sheet support segment 6, in particular the bracket 6, in particular the chain 8. The traction means, in particular the chain 8, is in particular also shifted in and/or counter to the sheet conveying direction BFR along the guide of the bracket 6. A respective fixing device is preferably connected to the traction device, in particular a chain link of chain 8, in such a way that an adjustment movement of the fixing device simultaneously causes an adjustment of the support elements assigned to the traction device, in particular the pressing elements 7 assigned to chain 8.

the 3 shows a perspective view of the sprocket shaft 4 with support elements, in particular pressing elements 7, bearing sheet support segments 6, in particular brackets 6, and fixing devices for the trailing edge of the sheet. The fixing devices are arranged in particular exclusively in the area of the sheet support segments 6, in particular bracket 6, between the sheet support segments 6, in particular bracket 6, with each fixing device being assigned directly to a sheet support segment 6, in particular bracket 6. Further fixing devices for the trailing edge of the sheet between the two outer fixing devices that fix the rear corners of the sheet are not provided. In particular, exactly one fixing device is assigned to a respective arch support segment 6 , in particular bracket 6 . A fixing device is preferably mounted immediately adjacent to a sheet support segment 6, in particular bracket 6, and/or movably mounted relative to a sheet support segment 6, in particular bracket 6, in particular for an adjustment. The fixing devices are format-adjustable, in particular in the longitudinal direction of the sheet, ie in the sheet conveying direction BFR, and/or in the sheet width direction, ie transversely to the sheet conveying direction BFR. The fixing devices are preferably designed to be format-adjustable together with support elements, in particular pressing elements 7, of the sheet support segments 6, in particular brackets 6. Preferably, the fixing devices with the support elements, in particular pressing elements 7, can be adjusted simultaneously or together by the drive located on the hub.

In particular, a respective fixing device for the trailing edge of the sheet contains a contact element which, preferably as a pneumatically acting sucker 10, fixes a limited region of the trailing edge of the sheet by suction. In particular, each fixing device, in particular each suction cup 10, has a separate pneumatic connection, with the pneumatic connections of the fixing devices, in particular suction cups 10, preferably being in pneumatic connection or flow connection with a common compressed air generator. The compressed air generator provides, in particular, a permanently higher than ambient pressure and/or unclocked pneumatic pressure, which is correspondingly available at the pneumatic connections of the fixing devices, in particular suction cups 10 . A compressor, for example, can be used as the compressed air generator. The pneumatic connection of the fixing devices, in particular suction cups 10, is particularly preferably also carried out via a rotary inlet 11 of the rotatably mounted chain wheel shaft 4, in particular with the realization of a trailing cable, for example in the middle of the machine. The compressed air generator is connected here in particular to the two laterally arranged fixing devices, in particular suction cups 10, which fix the sheet at the same time. In the case of the double-sized delivery drum, in particular chain wheel shaft 4, the compressed air generator is in pneumatic connection or flow connection with all or exactly four fixing devices, in particular suckers 10.

A contact element of the fixing device has an at least approximately flat contact surface for a sheet area. In particular, a sucker 10 has a suction surface that transfers a suction effect of the fixing device to the sheet. The pneumatically acting suckers 10 of the fixing devices preferably each have at least one opening for suction air generated in the suction surface, through which a sheet is held in contact with the sucker 10 . For example, each teat 10 can have a number of openings or suction openings, for example four to six suction openings. The fixing devices can also have, for example, exchangeable contact elements, in particular suction cups 10, which, for example, have openings or openings that are arranged or designed differently. The contact surface of a contact element or the suction surface of a sucker 10 can, for example, have an extension of up to 20 mm in the sheet conveying direction BFR and/or of up to 50 mm transversely to the sheet conveying direction BFR. Each fixing device is preferably assigned an air control element, in particular directly adjacent to the suction surface, which is preferably designed as a solenoid valve 13, particularly preferably as a quick-acting valve.

The fixing devices could also have a separate holder, but are preferably assigned directly to the arch support segments 6, in particular brackets 6. The contact surfaces of the contact elements, in particular the suction surfaces of the suction cups 10, of the fixing devices are preferably always kept level with the support elements, in particular the contact surfaces of the pressing elements 7, of the sheet support segments 6. For example, the contact elements, in particular suction cups 10, can be accommodated by a fixing device via a lockable plug connection. In particular, a contact element, in particular suction cup 10, can be assigned in the axial direction to a receptacle of the fixing device, the contact element, in particular suction cup 10, being able to be fixed in its position by the fixing device, for example via a ball catch. Differently designed contact elements, in particular suction cups 10, can thus be assigned to a fixing device in an exchangeable manner. In particular, contact elements, in particular suction cups 10, of different material composition and/or shape can be assigned to a fixing device so that they are interchangeable. For adjustment, assembly, cleaning and/or maintenance work, the contact elements, in particular suction cups 10, are assigned to the fixing devices so that they can be removed or replaced quickly or without tools.

the 4 shows a side view of the, for example, double-sized sprocket shaft 4 with support elements arranged on traction means, in particular pressing elements 7 arranged on chains 8. The chain 8 assigned to a respective bow support segment 6, in particular a bracket 6, is placed as a closed chain 8 around a bracket 6 and is Bracket 6 out in the circumferential direction. On the inner side, the chain 8 is held at a desired or adjustable tension by a tensioning means, here in particular by a tensioning roller 9 . An adjusting means, in particular a drive, preferably an electrically operated drive motor, is provided for displacing the chain 8 carrying the pressing elements 7 relative to the bracket 6 in and/or counter to the sheet conveying direction BFR, in particular for adjustment or format adjustment.

The chain 8 has chain links which are connected to one another in an articulated manner and to which the pressing elements 7 can be assigned. Exactly one pressing element 7 can be assigned to each chain link of the chain 8 . The pressing elements 7 are preferably assigned to the chain 8 so that they can be changed, it being possible for a respective pressing element 7 to be accommodated by a chain link of the chain 8 in a positive and/or non-positive manner. In particular, a pressing element 7 is received by a chain link of the chain 8 via a lockable plug connection. A pressing element 7 is preferably accommodated by a respective chain link of the chain 8 via a screw connection. This means that differently designed pressing elements 7 can be assigned to a respective chain link of a chain 8 in an exchangeable manner. In particular, pressing elements 7 of different material composition and/or shape can be assigned to a respective chain link of a chain 8 so that they are interchangeable. For adjustment, assembly, cleaning and/or maintenance work, the pressing elements 7 are assigned to the chain 8 or the arch support segments 6, in particular brackets 6, so that they can be quickly removed or exchanged.

the 5 shows an enlarged view of a sheet support segment 6, in particular bracket 6, with a chain 8 associated pressing elements 7 and a fixing device for the trailing edge of the sheet. The fixing device has a compressed air connection connected to the compressed air generator and works according to the ejector principle. In this case, the fixing device contains in particular an ejector 12, which opens into an outlet channel. Used air can escape via the outlet channel, which is directed, for example, in the direction of the shaft. Furthermore, deflection or dispersal means can be provided for the air emerging from the outlet duct. The fixing device preferably has an air control element, which is designed in particular as a solenoid valve 13 . Via the air control element, in particular solenoid valve 13, the suction effect of the respective fixing device is controlled, for example as a function of the machine speed and/or the properties of the printing material. All fixing devices are preferably designed as ejector suction cups. Each fixing device, in particular each suction cup 10, is preferably assigned an air control element, in particular a remote-controllable solenoid valve 13, for the individual and/or remote-controllable control of the suction effect, with the air control element, in particular the solenoid valve 13, in particular controlling the compressed air supplying the ejector 12.

An air control element, in particular a magnetic valve 13, of one or preferably each fixing device can be actuated by a control device, in particular the machine control. The electrical control connection is preferably also made via a rotary inlet 11 of the rotatably mounted sprocket shaft 4 and, if necessary, a trailing cable. An air control element, in particular a solenoid valve 13, can be actuated by the control device, in particular the machine control, for order-related adjustment of the pneumatic effect of the fixing device, in particular the sucker 10. The start, the intensity and/or the end of the pneumatic suction effect of the fixing device, in particular the suction cup 10, can be set or changed by the air control element, in particular the magnetic valve 13. The setting or change can also be made while the machine is running or during the printing process. The air control element, in particular solenoid valve 13, particularly preferably influences or adjusts the suction effect of the fixing device, in particular of the sucker 10, as a function of the machine speed and/or the properties of the printing material. The air control element, in particular the solenoid valve 13, can interact with the control device in such a way that the beginning, the intensity and/or the end of the pneumatic effect can be set manually or automatically.

The compressed air feeding the ejector 12 is controlled in particular by means of the solenoid valve 13 assigned to a fixing device, in particular a suction device 10, in such a way that the beginning, the intensity and/or the end of a suction effect is set. The setting of the suction air of the fixing device, in particular on the suction cup 10, by the air control element, in particular the solenoid valve 13, can also be made as a function of the sheet travel when the sheet is accepted and/or when the sheet is released. The sheet travel can therefore also be influenced or controlled or regulated individually and/or remotely during the printing process. An automated setting of the suction effect on the individual fixing devices, in particular suckers 10, of the sprocket shaft 4 can be carried out, for example, according to sensor values. In particular, when influencing the pneumatic suction effect, a dead time during the build-up of the suction effect can be taken into account. This dead time can also be compensated as a function of speed, for example.

the 6 shows an embodiment of a pressing element 7 for a chain 8 guided on a bracket 6. The pressing element 7 can be assigned to a chain link of the chain 8 in an exchangeable manner via a screw connection. The pressing element 7 is, in particular, designed to be elastic and has a contact surface for a sheet that extends in the circumferential direction and has a minimal axial extent. The pressing element 7 can be made of rubber, for example. An elasticity of the pressing element 7 can be achieved in particular by the choice of material and/or a suitable shape.

the 7 shows an embodiment of a contact element as a suction cup 10 for a fixing device. The suction cup 10 can be assigned to the fixing device, in particular the ejector 12, via a receptacle. For example, the suction cup 10 can have guide surfaces that are received or guided by guide surfaces of the fixing device. For example, the suction cup 10 can be assigned to the fixing device in the axial direction, with a lockable plug-in connection preferably being provided for fixing the position. For example, at least one hemispherical recess can be provided on the underside of the suction cup 10, which interacts positively with a spring-loaded locking ball of the fixing device to fix the position and thus enables the suction cup 10 to be changed or exchanged without tools.

The suction cup 10 has at least one and here in particular four openings and forms the suction surface for the trailing edge of the sheet with centrally arranged supporting elevations. The suction cup 10 is preferably dimensioned such that its suction surface is always or permanently at the height of the contact line of the directly adjacent support element, in particular the pressing element 7, of the sheet support segment 6. An elastic covering, such as a rubber covering, can also be assigned to the teat 10 . The or the breakthroughs of the suction cup 10 allow the effect of suction air generated by the ejector 12 in some areas on the sheet trailing edge, so that a suction force keeps the sheet trailing edge in contact with the suction surface of the suction cup 10.

About the mode of action: Before a new job, for example a new print job, the sheet support segments 6, in particular the bracket 6, can be placed axially on the side edges of the new sheet format. Beforehand, at the same time or also afterwards, the fixing devices, in particular suction cups 10, can be placed on the trailing edge of the new sheet format, with the supporting elements, in particular pressing elements 7, preferably being displaced at the same time in such a way that only the respective sheet side edge of the new sheet format is supported by supporting elements, in particular pressing elements 7, being contacted. If necessary, suitable support elements, in particular pressing elements 7, can be assigned to the sheet support segments 6, in particular brackets 6, and/or suitable contact elements, in particular suckers 10, to the fixing devices.

During the subsequent sheet travel, the sheet support segments 6, in particular bracket 6, or the support elements, in particular the pressing elements 7, support or press a respective sheet simultaneously against the cylinder surface of the upstream sheet guiding cylinder, in particular impression cylinder 2, with a respective trailing edge of the sheet next to the sheet support segments 6, in particular brackets 6, or the support elements, in particular the pressing elements 7, in the area of the sheet support segments 6, in particular bracket 6, or the supporting elements, in particular the pressing elements 7, held exclusively by the fixing devices arranged immediately adjacent, in particular suction cups 10, and to be led.

The suction air of the fixing devices, in particular suction cups 10, is preferably obtained according to the ejector principle from compressed air from a compressed air generator, with air control elements, in particular solenoid valves 13, assigned to the fixing devices, in particular suction cups 10, controlling the suction air with precise timing. If required, the suction air control can also be changed individually and/or remotely. For example, the air control elements, in particular solenoid valves 13, can be activated according to characteristic curves. This ensures maximum suction power during sheet transfer in the central transfer station. Subsequently, for example, the suction effect can be reduced as a function of the angle, since a lower suction force is sufficient to hold the trailing edge of the sheet lying against the suction surface of the suction device 10 .

Reference List

1

display

2

pressure cylinder

3

chain conveyor system

4

sprocket shaft

5

display pile

6

Arch support segment, stirrup

7

pressing element

8th

Chain

9

idler pulley

10

Mammal

11

rotary introduction

12

ejector

13

magnetic valve

BFR

sheet conveying direction

Claims (15)

Sheet transport device for a sheet-processing machine, with a sheet transport system (3, 4) that accepts a sheet from a sheet-guiding cylinder (2), with a gripping device (3) for clampingly fixing and transporting a respective leading edge of the sheet, and with at least two sheets simultaneously on the lateral surface of the sheet-guiding cylinder (2nd ) holding circulating sheet support segments (6) and pneumatic fixing devices (10) for the trailing edge of the sheet, characterized in that the fixing devices (10) are pneumatically connected to a compressed air generator, the compressed air generator having exactly four fixing devices (10) of a double-sized chain wheel shaft (4) is in pneumatic flow connection. device after claim 1 , whereby the compressed air generator provides a permanently higher than ambient pneumatic pressure. device after claim 1 or 2 , wherein the sheet conveying system has the sprocket shaft (4) and compressed air is provided via a rotary inlet (11) of a rotatably mounted shaft of the sprocket shaft (4). device after claim 1 , 2 or 3 , whereby the compressed air generator provides an unclocked pneumatic pressure. device after claim 1 , 2 , 3 or 4 , wherein the fixing devices (10) are arranged exclusively in the area of the sheet support segments (6) between the sheet support segments (6) and each fixing device (10) is assigned to a sheet support segment (6). device after claim 1 , 2 , 3 , 4 or 5 , wherein the arch support segments (6) carry support elements (7) which mechanically contact the arch and which are connected by means of a traction means (8), the fixing devices (10) each being connected to a traction means (8). device after claim 1 , 2 , 3 , 4 , 5 or 6 wherein the fixing devices (10) are designed to be format-adjustable in and/or counter to the sheet conveying direction (BFR) and/or transversely to the sheet conveying direction (BFR) and/or to be format-adjustable together with support elements (7) of the sheet support segments (6). device after claim 1 , 2 , 3 , 4 , 5 , 6 or 7 , wherein each fixing device (10) has a separate holder and / or a separate pneumatic connection. device after claim 1 , 2 , 3 , 4 , 5 , 6 , 7 or 8th , wherein the fixing devices have pneumatically acting suction cups (10), which each have at least one opening and/or are assigned to the fixing devices in an exchangeable manner. device after claim 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8th or 9 , wherein the fixing devices (10) work according to the ejector principle and have an outlet channel for escaping air. device after claim 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8th , 9 or 10 , wherein each fixing device (10) is assigned a respective air control element (13) for controlling the suction effect of the respective fixing device (10). device after claim 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8th , 9 , 10 or 11 , wherein each fixing device (10) is assigned a respective air control element (13) for controlling the suction effect of the respective fixing device (10) depending on the machine speed and/or the properties of the printing material. device after claim 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8th , 9 , 10 , 11 or 12 , wherein the fixing devices (10) are designed as ejector suction cups and each fixing device (10) is assigned a remote-controllable solenoid valve (13) which controls the compressed air feeding the ejector (12). Method for transporting sheets from a sheet guiding cylinder (2) to a sheet conveying system (3, 4) in a sheet processing machine, wherein a gripping device (3) clamps a respective front edge of the sheet for transport, the sheet being supported by at least two circulating sheet support segments (6) at the same time is held on the lateral surface of the sheet guiding cylinder (2) and the trailing edge of the sheet is held by pneumatic fixing devices (10), characterized in that the fixing devices (10) are pneumatically connected to a compressed air generator to generate forces that hold the sheets, the compressed air generator being exactly four fixing devices (10) of a double-sized sprocket shaft (4) are in pneumatic flow connection. procedure after Claim 14 , wherein the suction effect of the fixing devices (10) is changed and/or adjusted by means of air control elements (13) acting on the compressed air supplying the fixing devices (10).

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