Device and method for unstacking a stack

Abstract

An inventive device for destacking a stack, wherein the stack (3) is composed of sub-stacks (5) of flat printed products (4) arranged side by side and one above the other, wherein the device (1) comprises a separating device (10) for preferably temporarily forming a gap (7) between a respective sub-stack (5) and the stack (3), and a gripping device (20) for gripping and lifting the respective sub-stack (5) using the respective gap (7), and wherein the device (1) comprises a first robot (40) which moves the gripping device (20) during destacking, is characterized in that the device (1) comprises a second robot (50) which moves the separating device (10) separately. Preferably, the two robots are identical gantry robots mounted on a common gantry frame.The invention advantageously enables an increase in processing speed during the depalletizing of stacks through process parallelization. The invention is used, for example, in post-press applications (print finishing).

Description

invention

[0001] The invention relates to a respective device for unstacking a stack having the features of the preamble of claim 1 or claim 19.

[0002] The invention relates to a method for destacking a stack with the features of the preamble of claim 22. field of technology

[0003] The invention lies in the technical field of the graphic arts industry and there in particular in the area of ​​handling (e.g. gripping, holding, lifting, moving and setting down) stacks of superimposed, flexible and preferably printed and die-cut flat products such as printed sheets or die-cut blanks, preferably made of paper, cardboard, corrugated board, plastic or composite material, with a manipulator, in particular a robot with robot arm and gripper device for the stacks. State of the art

[0004] It is already known to depalletize stacks of sheets using robotic technology and to separate the stacks section by section before gripping and lifting.

[0005] WO2017177393A1 discloses a depalletizing system for a stack comprising a robot arm and a gripper head mounted on the robot arm and moved by it during depalletizing. The gripper head, as the gripping device, includes an upper gripper and a lower gripper. The gripper head also includes a separating device designed as a hook. Thus, the gripping device and the separating device are moved together by the same robot arm, and the robot must be dimensioned accordingly.

[0006] It is also already known to use multiple robots for depalletizing.

[0007] US20100146907A1 and US20170173800A1 each disclose a system in the field of palletizing / depalletizing in which two identical robots are used, i.e. the robots and their tools are identically constructed and perform the same tasks (individually or together).

[0008] Manufacturers of graphic products – such as printing companies with prepress, printing, and finishing departments – constantly demand increased production speed, which is why robotics is being used more and more. This also allows for personnel savings or the replacement of missing personnel. Technical task

[0009] It is now an object of the present invention to provide an improvement over the prior art, which in particular makes it possible to increase the processing speed when depalletizing stacks. Inventive solution to the problem

[0010] This problem is solved according to the invention by a respective device according to claim 1 or claim 19.

[0011] This problem is also solved according to the invention by a method according to claim 22.

[0012] A first device according to the invention for unstacking (alternatively: depalletizing) a stack, wherein the stack is composed of sub-stacks of flat printed products arranged side by side and one above the other, wherein the device comprises a separating device for preferably temporarily forming a gap between a respective sub-stack and the stack and a gripping device for gripping and preferably lifting the respective sub-stack using the respective gap, and wherein the device comprises a first robot which moves the gripping device during unstacking, is characterized in that the device comprises a second robot which moves the separating device separately.

[0013] A second device according to the invention for destacking a stack, wherein the stack is composed of sub-stacks of flat printed products arranged side by side and one above the other, and wherein the device comprises a first robot with a gripper device, is characterized in that the device comprises a second robot with a separating device.

[0014] A method according to the invention for destacking a stack, wherein the stack is composed of sub-stacks of flat printed products arranged side by side and one above the other, wherein the sub-stacks are first separated from the stack by forming a gap and then gripped and lifted off, is characterized in that the separation is effected by a separation device arranged on and moved by a first robot and that the gripping and lifting is effected by a gripping device arranged on and moved by a second robot.

[0015] Advantageous and therefore preferred embodiments of the inventions are evident from the dependent claims as well as from the description and the drawings. Advantageous forms and effects of the invention

[0016] The invention advantageously enables an increase in processing speed when depalletizing stacks. The invention is used, for example, in post-press processing (print finishing).

[0017] The invention divides the two process steps of separating and gripping between two handling devices. Advantageously, the invention allows the use of two robots to parallelize depalletizing process steps, thereby increasing the speed, and in particular the cycle times, of the operation. A further advantage of the invention is that identical robots (with the different tools: gripping device and separating device) can be used, thus reducing complexity and therefore costs.

[0018] The individual flat printed products can be folding carton blanks, and it may be planned to depalletize them and then feed them to a folding carton gluing machine. It may also be planned to depalletize the products and repalletize them on another pallet, for example, to create single-product pallets from mixed pallets or to produce a tighter packing pattern. Further developments of the invention

[0019] Preferred embodiments of the invention are described below as first devices (hereinafter referred to as embodiments). These can also be combined with one another, unless technically precluded.

[0020] A further development can be characterized by the fact that the gripping device is designed as a gripper head, which is movably arranged on the first robot. The gripper head can have a compact design. It can be provided that the gripper head is rotatably arranged on the first robot, in particular about a vertical axis. It can be provided that the gripper head comprises a pair of grippers consisting of a lower gripper and an upper gripper. The upper gripper can be movable back and forth in the direction of the lower gripper, in particular in the vertical direction. It can be provided that the separating device is designed as a separating head, which is movably arranged on the second robot. The separating head can also have a compact design. It can be provided that the separating head is rotatably arranged on the second robot, again in particular about a vertical axis.It may be provided that a gap is formed between the underside (bottom printed product) of a given sub-stack and the top side (top printed product) of the stack below it. It may be provided that the lower gripper is moved wholly or partially into this gap, particularly in a horizontal direction.

[0021] A further development can be characterized by the separating head comprising a first lifting device for selectively and preferably temporarily lifting the partial stack and creating the gap. The gap is preferably formed temporarily, i.e., only until the partial stack is gripped and then lifted from the stack, in particular from a pallet stack. The first lifting device may contact the partial stack on a vertical side during lifting. The first lifting device may exert a pressing action. The separating head may also include a vertically movable second lifting device for selectively and preferably temporarily lifting the partial stack and creating or further creating the gap. Both lifting devices may be pneumatically activated. The second lifting device may contact the partial stack on a horizontal underside during lifting, in particular by gripping underneath it.It may be provided that the second lifter enters between the bottommost product of the sub-stack and an intermediate layer underneath, e.g. a sheet of cardboard.

[0022] A further development can be characterized by the fact that the separating head includes at least one controllable drive for the horizontal movement of the first lifter and / or the second lifter. Preferably, a common drive is provided. The drive can be an electric linear drive. The electric linear drive can have at least three horizontal positions: in the first position, both lifters are in a passive position outside the partial stack; in the second position, only the first lifter is in its active position on the partial stack; and in the third position, both lifters are in their respective active positions on or under the partial stack.

[0023] A further development can be characterized by the fact that the separating head includes a vertically movable pressure plate. This is preferably pneumatically actuated. It can be provided that the separating head separates a partial stack from the stack at least partially, e.g., less than 10%, 5%, or 1% of the surface area of ​​the bottommost printed product. It can be provided that the separating head separates the partial stack from the stack only in the area of ​​a lower edge. It can be provided that the separating head creates a gap between the partial stack and the stack. The gap is preferably less than 10 mm or less than 5 mm high. It can be provided that the partial stack separated from the stack continues to rest on the stack within the area of ​​effect of the pressure plate. The area of ​​effect is the area in which the pressure plate presses the partial stack downwards onto the stack.It may be provided that the gripping head or at least a part of the gripping head enters the gap, in particular at least one prong of the gripping head.

[0024] A further development can be characterized by the fact that the device includes a digital computer which controls both the movement of the first robot and the activation of the gripping device, as well as the movement of the second robot and the activation of the separating device, such that a sub-stack is first separated from the stack and then gripped. It can be provided that the separated and gripped sub-stack is lifted from the stack and moved away. It can be provided that the sub-stack is placed elsewhere, i.e., not at the location of the stack, e.g., at a downstream processing machine. It can be provided that the stack is structured according to a placement scheme for the sub-stacks and that the digital computer controls both the movements of the first robot and the movements of the second robot when dismantling the stack, referring to the placement scheme.The stacking scheme defines the respective position and orientation of each sub-stack within the (overall) stack, preferably also the XYZ dimensions of the sub-stacks. The device may include a detection device, i.e., a device for geometrically detecting the stack, a region of the stack, at least one sub-stack, and / or a region of the at least one sub-stack. The detection device may be fixed to the device. Alternatively, the detection device may be movable, e.g., automatically adjustable. The detection device may be located on the separating head. Finally, the detection device may include at least one camera and / or a line scanner.It can be arranged that the data acquisition system provides data and that the digital computer uses this data for a target / actual comparison with the depalletizing scheme. In this way, the digital computer can detect whether the sub-stacks have been incorrectly placed or have shifted and can take this into account as a preferential corrective measure during depalletizing.

[0025] A further development can be characterized by the fact that the gripper head is located on the first robot. A further development can be characterized by the fact that the first robot is controllable such that the gripper head can move in three spatial directions: in a horizontal longitudinal direction X, in a horizontal transverse direction Y, and in a vertical vertical direction Z. The first robot can be designed as a gantry robot, in particular with three translational axes. Gantry robots provide a cubic workspace, which is well suited to the process of stacking an essentially cubic stack from a (rectangular) pallet. The first gantry robot can include a first longitudinal guide in the X direction. The first gantry robot can also include a first transverse guide in the Y direction.The first gantry robot may include a first vertical guide in the Z-direction. The first gantry robot may include a first vertical support in the Z-direction. The gripper head may be rotatably mounted on the first vertical guide about at least one axis of rotation. The first axis of rotation may be a vertical axis.

[0026] A further development can be characterized by the fact that the lower gripper comprises at least one prong. It can be provided that at least two prongs are present and that the prongs are adjustable in size and / or interchangeable, e.g., manually or automatically. It can be provided that the upper gripper comprises at least one prong. It can be provided that at least two prongs are present and that the prongs are adjustable in size and / or interchangeable, e.g., manually or automatically. It can be provided that the upper gripper is movable relative to the lower gripper, preferably pneumatically. It can be provided that the upper gripper is vertically movable.

[0027] A further development can be characterized by the fact that the gripper head includes the lower gripper, the upper gripper, and a drive for the movable upper gripper. The drive may be a hydraulic cylinder. The drive may also be controllable.

[0028] A further development can be characterized by the fact that the cutting head is arranged on the second robot. The second robot can be controlled such that the cutting head is movable in the three spatial directions X, Y, and Z. The second robot can be designed as a second gantry robot, in particular with three translational axes. The second gantry robot can include a second longitudinal guide in the X direction. The second gantry robot can include a second transverse guide in the Y direction. The second gantry robot can include a second vertical guide in the Z direction. The second gantry robot can include a second vertical support in the Z direction. The cutting head can be rotatably arranged on the second vertical guide about at least a second axis of rotation.It may be provided that the second axis of rotation is a vertical axis.

[0029] Further training can be characterized by the fact that the movements of the gripper device and / or the movements of the separating device encompass a common workspace. This workspace can be defined by the sum of all reachable or all necessary reachable locations in the XYZ space. It may be stipulated that the stack for dismantling is placed entirely or at least partially within the workspace.

[0030] A further development can be characterized by the fact that the first and second robots are configured as gantry robots and arranged on a common gantry frame. This arrangement reduces the risk of robot collisions compared to two cooperating articulated robots. Furthermore, the gantry frame preferably defines a safety zone that operating personnel are not permitted to enter during operation and which is preferably monitored for this purpose. The gantry frame may comprise several, in particular four, supports that span a preferably cubic space. The workspace may be located within this space, and in particular, the workspace may be smaller than the space. The first and second robots may be identical in construction.The stack may be built on a pallet, and the pallet may be placed in the space between the stacks for dismantling, preferably on a floor or conveyor system within the production facility. The pallet may be movable into the space from at least one side. It may also be movable into the space from two or three sides. Furthermore, the pallet may be moved automatically using a mobile AGV (automated guided vehicle) or a pallet conveyor system mounted on or in a floor.

[0031] Preferred embodiments of the invention are described below as second devices (hereinafter referred to as embodiments). These can also be combined with one another, unless technically precluded.

[0032] A further development can be characterized by the fact that the device includes a third robot with an additional gripping device. The first and second robots can be configured as gantry robots. The first and second robots can be arranged on a common gantry frame. The third robot can be configured as an articulated arm robot. The third robot can be configured as a gantry robot, preferably identical in construction to the first and second gantry robots. The first, second, and third robots can be arranged on a common gantry frame, in particular with four or six supports. The respective workspaces of the three robots can partially overlap, especially for transferring partial stacks at a transfer point.

[0033] Preferred embodiments of the invention are described below as methods (hereinafter referred to as embodiments). These can also be combined with one another, unless technically precluded.

[0034] Further processing can be characterized by the second robot placing a partial stack onto an intermediate storage area (alternatively: buffer). It can be provided that a third robot with another gripper picks up the partial stack from the intermediate storage area and places it again elsewhere. In this case, the intermediate storage area can also be considered a transfer point. It can be provided that the second placement takes place on a feeder of a downstream processing machine.

[0035] Further training can be characterized by the fact that the second robot transfers a partial stack to a third robot with another gripping device without intermediate placement. The transfer can take place freely "in mid-air".

[0036] A further processing system can be characterized by the fact that the intermediate storage comprises multiple intermediate storage locations. The intermediate storage locations can be arranged horizontally side by side, e.g., in the transverse Y direction. The intermediate storage locations can be arranged vertically one above the other, e.g., in the Z direction. The intermediate storage locations can be arranged in an intermediate storage rack. The rack can comprise several levels. The second robot can fill the intermediate storage locations from one long side, and the third robot can empty the intermediate storage locations from an opposite long side or from a transverse side.It can be arranged that the second robot fills the intermediate storage locations from one transverse side and that the third robot empties the intermediate storage locations from an opposite transverse side or from one longitudinal side. The two robots, or rather their gripping devices, can therefore grasp the partial stack to be transferred at an angle of 90° or 180°.

[0037] It may be provided that at least one intermediate storage location is designed as a cam surface. The cams (alternatively: projections, particularly in the Z-direction) are preferably arranged and spaced apart from one another such that the tines of a lower gripper can temporarily move in and out under the partial stack and between the cams, thereby placing or lifting the partial stack. The cams can be arranged in a regular grid. The tines can preferably be selectively moved in and out from either the longitudinal or the transverse sides.

[0038] The technical features disclosed in the above sections Technical Field, Invention and Further Developments, as well as in the section Exemplary Embodiments, may represent further advantageous developments of the invention as those combinations of features which can be derived from this application. Exemplary embodiments of the invention and figures

[0039] The Fig. Figures 1 to 8 show preferred embodiments of the invention and its further developments. Corresponding features are identified in the figures by the same reference numerals. For clarity, some reference numerals that are repeated in the figures have been omitted. Fig. Figure 1 shows a perspective view of a preferred embodiment of a device according to the invention. Fig. 2 and Fig. 3 each show a side view and Fig. 4. A top view of the same device. Fig. Figure 5 shows a side view of a preferred gripping device. Fig. Figure 6 shows a side view of a preferred separating device. The Fig. Figures 7A to 7F show a sequence when forming a gap. Fig. Figure 8 shows a side view of a schematic representation of a preferred embodiment of a device according to the invention. Fig. Figure 9 shows a cam surface in two side views.

[0040] Fig. Figure 1 shows a device 1 according to the invention for carrying out a method according to the invention for destacking a pallet 2 or the stack 2 located on it (cf. Figure 1). Fig. 2 and Fig. 3) The stacked printed products 4 each form sub-stacks 5, which together form the stack 3.

[0041] The device 1 comprises a portal frame 30 with, for example, four uprights, which define a space 32 in which a workspace 33 for robots is located. The pallet 2 with the stack 3 can be moved into the workspace 33 for destacking, preferably in different directions 90. The portal frame has a longitudinal side 75, a longitudinal side 76 opposite it, a transverse side 77, and a transverse side 78 opposite it; the pallet 2 can be moved into the workspace from one of the longitudinal sides or from one of the transverse sides. The movement of the pallet 2 (into and out of the workspace) is carried out, for example, by an AGV 85, or alternatively by a preferably underfloor pallet conveyor 86; however, it can also be done manually with a pallet truck.

[0042] The device 1 comprises a first robot 40, which is configured as a gantry robot on a gantry frame 30 with a first longitudinal guide 41 (in the X direction), a first transverse guide 42 (in the Y direction) movable in the X direction, a first vertical guide 43 (in the Z direction) movable in the Y direction, a first vertical support 44 (in the Z direction), and a first rotary axis 45 at the end of the vertical support 44. The first robot 40 can perform movements 98a in the X, Y, and / or Z directions.

[0043] The device 1 also includes a second robot 50, which is also configured as a gantry robot on the gantry frame 30, but with a second longitudinal guide 51 (in the X direction; identical to the first longitudinal guide 41 in this example), a second transverse guide 52 (in the Y direction) movable in the X direction, a second vertical guide 53 (in the Z direction) movable in the Y direction, a second vertical support 54 (in the Z direction), and a second rotary axis 45 at the end of the vertical support. The second robot 50 can perform movements 98b in the X, Y, and / or Z directions.

[0044] The two robots, 40 and 50, are portal robots and include the usual drives for the respective X, Y and Z movements of their tools.

[0045] The two robots 40 and 50, and their coordinated and collision-free movements, are controlled by a digital computer 82. This computer has access to the digitally stored placement pattern 83, which is used for the stack 3 currently being dismantled. A digital camera 84 is also mounted on the portal frame 30 to capture the stack 30 and to detect deviations from the placement pattern 83 and correct them if necessary.

[0046] In Fig. 2 is the same device 1 from the longitudinal side 75 and in Fig. 3 shown from the side 77.

[0047] The Fig. 1 to 3 together with Fig. It can be seen from Figure 5 that a mobile gripping device 20 is arranged on the first robot 40, which includes a gripper head 21 for gripping one partial stack 5 at a time. The gripper head 21, as a robot-guided tool, is movable in the X, Y, and Z directions (movements 91 and 92) and can be positioned and rotated about the Z-axis. The gripper head 21 comprises a pair of grippers 22, consisting of a lower gripper 23 with prongs 24 and a vertically movable upper gripper 25 with prongs 26. The gripping device 20 includes a controllable drive 27 for the rotary movement of the gripper head 21. The gripper head 21 includes a controllable drive 28 for the translational movement of the upper gripper 28 (movement 94), i.e., for gripping one partial stack 5 at a time.

[0048] The Fig. 1 to 3 together with Fig. It can also be seen from Figure 6 that a mobile cutting device 10 is arranged on the second robot 50, which includes a cutting head 11 for cutting one stack of parts 5 at a time. The cutting head 11, as a robot-guided tool, is movable or positionable in the X, Y, and Z directions and rotatable about the Z-axis. The cutting head 11 comprises a first lifter 12 and a second lifter 13, as well as a pressure plate 15. The cutting device 10 includes a controllable drive 17 for the rotary movement of the cutting head 11. The cutting head 11 includes a controllable drive 18 for the translational movement of the pressure plate 15 and a controllable drive 19 for the translational movement of the two lifters 12 and 13.

[0049] In Fig. Figure 4 shows the same device 1 in a top view. In the working area of ​​at least the gripping device 20, there is an intermediate storage area 70, which is designed as a horizontally positioned cam surface 71 with upwardly extending, grid-like arranged cams 71 and on which at least one partial stack 5 can be temporarily placed and thus temporarily stored until picked up again. The intermediate storage area 70 is part of an intermediate storage rack 73 with at least two intermediate storage positions 74 spaced sufficiently apart above and from each other (corresponding to the maximum height of the partial stacks 5 to be handled), wherein in the Fig. Only the uppermost intermediate storage location 74 is visible in Figure 4. The top view also shows that the separating head 11 and the gripping head 21, and in particular their lifters and tines, are designed such that these elements can move without collision during separating and gripping; for example, the lifters can be temporarily positioned between the tines. Finally, it is evident that the two transverse guides 42 and 52 of the robots 40 and 50 cannot move past each other; that is, the movement control system must take this into account. Alternatively, it is also possible to provide several longitudinal guides, e.g., one above the other, so that movement past each other is possible.

[0050] Fig. Figure 5 shows the gripping device 20 with gripper head 21, gripper pair 22, lower gripper 23, lower gripper tines 24, upper gripper 25, upper gripper tines 26, drive 27 and drive 28. To grip and lift the partial stack 5, the open gripper pair 22 moves into the stack 3 and is then closed (lowering of the tines 26). Beforehand, however, the partial stack 5 is separated from the stack 3 (see figure sequence 77A to 7F).

[0051] Fig. Figure 6 shows the separating device 10 with separating head 11, first lifter 12, second lifter 13, pressure plate 15, and the drives 17, 18, and 19. The operating range of the pressure plate 16 is also indicated. The two lifters 12 and 13 can be moved into horizontal positions 14 for separating a partial stack 5 (see Figures 77A to 7F).

[0052] The Fig. Figures 6 and 7A to 7F show a sequence of steps in forming a gap 7: • 6: The separating device 10 is moved vertically and horizontally towards the partial stack 5 to be handled (movement 92). • 7A: The press 15 is moved downwards and presses the partial stack 5 downwards in its effective area 16 onto the stack 3 (movement 97) or onto the top 3a of the (remaining) stack 3 located below the partial stack 5. • 7B: The first lifter 12 is moved horizontally to a vertical side 5c of the sub-stack 5 and touches it (movement 95). The first lifter 12, or rather its contact element 12a, is pressed against the side 5c by means of a spring. • 7C: The robot 50 lifts the gripper head 21 (movement 92); simultaneously, the pressure plate 15 is moved downwards accordingly (movement 97). In doing so, the first lifter 12 slightly lifts the partial stack, creating a gap 7 between the horizontal underside 5a or the lowest product 6 of the partial stack 5 and the top side 3a. • 7D: The second lifter 13 is lowered to the level of the gap 7 (movement 96); if an intermediate layer 8 is present in the stack 3: to the intermediate layer. • 7E: The second lifter 13 or its lifting element 13a is moved horizontally into the gap 7 (movement). • 7F: The robot 50 lifts the gripper head 21 along with the second lifter 13 (movement 92); simultaneously, the pressure plate 15 is moved downwards again to the same extent (movement 97). This enlarges the existing gap 7. The sub-stack 5 is thus sufficiently separated from the stack in the area of ​​its lower edge 5b, so that a lower gripper tine 24 of the gripper head 21 can enter the gap 7 and then preferably move completely under the sub-stack 5 to lift the sub-stack 5.

[0053] Fig. Figure 8 shows the device 1 already described for destacking a pallet 2 or the stack 3 on it from sub-stacks 5 in the vicinity of a graphic arts plant, e.g., a printing plant, with at least two machines 80 and 81. Machine 80 is, for example, a printing press with a die-cutting module and produces printed and die-cut products 4, e.g., folding carton blanks, which are destacked into a stack 3 in sub-stacks 5 using a suitably selected detachment scheme 83, preferably using an articulated robot arm, e.g., a so-called cobot. Machine 81 is, for example, a folding carton gluing machine, to which the sub-stacks 5 lifted from the stack 3 are fed. A (underfloor) pallet conveyor 86 is provided in the floor 87 of the production facility, which conveys the loaded pallets 2 from machine 80 into the work area 33 and returns empty pallets.

[0054] The first portal robot 40 with gripper 20 and the second portal robot 50 with separator 10 are movably mounted on the portal frame 30. Additionally, a third robot 60, also a portal robot, with a further gripper 61 (similar to or identical to gripper 20) is mounted on the portal frame (alternatively: on an extension of the portal frame or on another portal frame). The third robot 60 can alternatively be configured as an articulated robot, e.g., as a so-called cobot. During operation, the robots perform movements 98a, 98b, and 98c.

[0055] The device 1 has an intermediate storage rack 73 with several intermediate storage positions 74 arranged one above the other; in the example shown, there are three. The gripping device 20 places partial stacks 5 onto cam surfaces 71 of the rack 73, and the other gripping device 61 picks them up again and moves them to the machine 81. The intermediate storage rack 73 can be used as a buffer, i.e., filled in advance and emptied as needed. Several partial stacks 5 can be buffered on each cam surface 71, if necessary.

[0056] The control of the device 1, i.e. in particular the coordinated robot movements, is carried out by means of the digital computer 82 using the stored placement scheme 83 and, if necessary, a camera 84 which captures the workspace 33.

[0057] Fig.Figure 9 shows a cam surface 71 with cams 72 or a cam support: on the left from a longitudinal side and on the right from a transverse side. On the left, it can be seen that the lower gripper tines 24 of the gripping device 20 move between the cams 72 when a partial stack 5 is placed onto the cams 72 (and then extend again). On the right, it can be seen that corresponding tines of the further gripping device 61 also move between the cams 72 when the partial stack 5 is lifted from the cams 72. The placement and re-pickup of the partial stack 5 thus takes place once from the longitudinal side and once from the transverse side, i.e., offset by 90°. In this way, the partial stack 5 can be rotated about a vertical axis, moved further, and fed to a machine. Alternatively, re-pickup can also take place from the longitudinal side or the opposite longitudinal side, i.e., without rotation. Reference symbol list 1 Device 2 pallets 3 stacks 3a Top of the stack 4 printed products 5 sub-stacks 5a (horizontal) underside of the substack 5b Bottom edge of the substack 5c vertical side of the substack 6 bottom product of the substack 7 Gap 8 Intermediate layer 10 Separating device 11 Separating head 12 first lifter 12a Contact element 13 second lifter 13a Lifting element 14 horizontal positions 15 pressure plates 16 Operating range of the pressure plate 17 Controllable drive for the cutting head (rotation) 18 Controllable drive for the press (translation) 19 Controllable drive for the jacks (translation) 20 Gripping device 21 Gripper head 22 pairs of grippers 23 Undercrawlers 24 prongs 25 upper grabbers 26 prongs 27 Controllable drive for the gripper head (rotation) 28 Controllable drive for the upper gripper (translation) 30 Portal frame 31 stands 32 space 33 Workroom 40 first robots, especially portal robots 41 first longitudinal guidance 42 first transverse guide 43 first vertical guide 44 first vertical beam 45 first axis of rotation 50 second robots, especially portal robots 51 second longitudinal guide 52 second transverse guide 53 second vertical guide 54 second vertical beam 55 second axis of rotation 60 third robot, especially portal robot or articulated arm robot 61 additional gripping devices 70 buffers 71 cam surface 72 cams 73 Intermediate storage shelf 74 intermediate storage space(s) 75 Long side 76 opposite long side 77 Cross side 78 opposite side 80 Machine, in particular folding machine 81 Finishing machine, in particular binder or stapler 82 digital computers 83 digital drop-off scheme 84 Detection device, in particular camera 85 FTF (driverless transport vehicle) 86 pallet conveyor system 87 Floor 90 movement(s) of the stack 91 Movement(s) of the gripping device / gripper head 92 Movement(s) of the separating device / separating head 93 Movement(s) of the underhook 94 Movement(s) of the upper gripper 95 Movement(s) of the first lifter 96 Movement(s) of the second lifter 97 Movement(s) of the pressure plate 98a Movement(s) of the first robot 98b Movement(s) of the second robot 98c Movement(s) of the third robot X horizontal longitudinal direction Y horizontal transverse direction Z vertical direction QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2017177393A1

[0005] US 20100146907A1

[0007] US 20170173800A1

[0007]

Claims

[1] Device for destacking a stack, wherein the stack (3) is composed of sub-stacks (5) of flat printed products (4) arranged side by side and one above the other, wherein the device (1) comprises a separating device (10) for forming a gap (7) between each sub-stack (5) and the stack (3) and a gripping device (20) for gripping the respective sub-stack (5) using the respective gap (7), and wherein the device (1) comprises a first robot (40) which moves the gripping device (20) during destacking, characterized by that the device (1) comprises a second robot (50) which moves the separating device (10) separately. [2] Device according to claim 1, characterized by , that the gripping device (20) is designed as a gripping head (21) which is movably arranged on the first robot (40). [3] Device according to one of the preceding claims 1 or 2, characterized by, that the separating device (10) is designed as a separating head (11) which is movably arranged on the second robot (50). [4] Device according to any one of the preceding claims 1 to 3, characterized by , that the gap (7) is formed between the bottom (5b) of each sub-stack (5) and the top (3a) of the stack (3) below it. [5] Device according to any one of the preceding claims 1 to 4, characterized by , that the separating head (11) includes a first lifter (12) for partially lifting the sub-stack (5) and for creating the gap (7). [6] Device according to claim 5, characterized by , that the first lifter (12) touches the sub-stack (5) on a vertical side (5c) when lifting. [7] Device according to one of the preceding claims 5 or 6, characterized by, that the separating head (11) includes a vertically movable second lifter (13) for selectively lifting the partial stack (5) and creating the gap (7). [8] Device according to claim 8, characterized by , that the second lifter (13) touches the sub-stack (5) on a horizontal underside (5a) when lifting. [9] Device according to any one of the preceding claims, characterized by , that the separating head (11) includes a vertically movable pressure plate (15). [10] Device according to any one of the preceding claims, characterized by , that the device (1) comprises a digital computer (82) which controls both the movement (98a) of the first robot (40) and the activation of the gripping device (20) as well as the movement (98b) of the second robot (50) and the activation of the separating device (10) such that a partial stack (5) is first separated from the stack (3) and then gripped. [11] Device according to claim 10, characterized by, that the stack (3) is set up according to a placement scheme (83) for the sub-stacks (5) and that the digital computer (82) controls both the movements (98a) of the first robot (40) and the movements (98b) of the second robot (50) when dismantling the stack (3) by referring to the placement scheme (83). [12] Device according to any one of the preceding claims, characterized by , that the first robot (40) is trained as a first portal robot. [13] Device according to claim 12, characterized by , that the second robot (50) is trained as a second portal robot. [14] Device according to any one of the preceding claims, characterized by , that the movements (91) of the gripping device (20) and / or the movements (92) of the separating device (10) span a common working space (33). [15] Device according to claim 14, characterized by, that the stack (3) is placed wholly or at least partially in the workspace (33) for dismantling. [16] Device according to any one of the preceding claims, characterized by , that the first robot (40) and the second robot (50) are designed as portal robots and are arranged on a common portal frame (30). [17] Device according to claim 16, characterized by , that the portal frame (30) comprises several uprights (31) which span a space (32). [18] Device according to claim 17, characterized by , that the workspace (33) lies in the intermediate space (32). [19] Device for destacking a stack, wherein the stack (3) is composed of sub-stacks (5) of flat printed products (4) arranged side by side and one above the other, and wherein the device (1) comprises a first robot (40) with a gripper device (20), characterized bythat the device (1) comprises a second robot (50) with a separating device (10). [20] Device according to claim 19, characterized by that the device (1) comprises a third robot (60) with a further gripping device (61). [21] Device according to claim 20, characterized by , that the first robot (40), the second robot (50) and the third robot (60) are arranged on a common portal frame (30). [22] Method for destacking a stack, wherein the stack (3) is composed of sub-stacks (5) of flat printed products (4) arranged side by side and one above the other, wherein the sub-stacks (5) are first separated from the stack (3) by forming a gap (7) and then grasped and lifted off, characterized by, that the separation is effected by a separation device (10) arranged on and moved by a first robot (40) and that the gripping and lifting is effected by a gripping device (20) arranged on and moved by a second robot (50). [23] Method according to claim 22, characterized by , that the second robot (50) places a partial stack (5) onto an intermediate storage area (70). [24] Method according to claim 23, characterized by , that a third robot (60) with another gripping device (61) lifts the partial stack (5) from the intermediate storage (70) and places it elsewhere. [25] Method according to claim 22, characterized by , that the second robot (50) transfers a partial stack (5) without intermediate placement to a third robot (60) with another gripping device (61). [26] Method according to any one of the preceding claims 22 to 25, characterized by, that the buffer (70) includes several buffer locations (74). [27] Method according to claim 26, characterized by , that the intermediate storage locations (74) are arranged in an intermediate storage rack (73). [28] Method according to one of the preceding claims 26 or 27, characterized by , that at least one intermediate storage location (75) is designed as a cam surface (71).

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