Method for handling stacks of flat products with a robot arm

Abstract

A method according to the invention for handling stacks of flat products, e.g. flat folding box blanks, wherein a robot arm (2) picks up individual stacks (3) one after the other at an upstream station (30), preferably by means of a gripper head (10), and wherein the individual stacks (3) are each brought into a tilting state (7) after being picked up, in which the flat products (4) of a respective stack (3) are displaced parallel to one another, is characterized in that the individual stacks (3) are passed on by the robot arm (2) to a downstream station (32) in the maintained tilting state (7). The tilting state can be generated using an alignment device (20), which is preferably part of an alignment station (31) or of the gripper head (10); in both cases the gripper head (10) is preferably tilted for tilting the stack (3).The invention advantageously enables the production flow in the manufacture of graphic products to be improved, particularly by achieving greater speed and accuracy. The invention is used, for example, in the production of folding trays.

Description

invention

[0001] The invention relates to a method having the features of the preamble of claim 1. field of technology

[0002] The invention lies in the technical field of the graphic industry and there in particular in the field of handling (e.g. gripping, holding, lifting, moving, and / or setting down) stacks of superimposed, flexible and preferably printed and punched flat products, such as folding box blanks, preferably made of cardboard or composite material, with a manipulator, in particular an articulated arm robot / articulated arm robot with a robot arm and gripping device for the stacks. State of the art

[0003] It is already known in the state of the art in the graphic arts industry to grip, lift, move, and set down stacks of flat products using a robot or its gripper head, for example, from DE102023124557A1. This also discloses intermediate movements, but for the specific purpose of forming intermediate stacks from two stacks lying one above the other.

[0004] US2018366766A1 already discloses a generic method, but for handling stacks of battery plates. A robot arm successively picks up individual stacks, places them in an alignment station, and retrieves them from the alignment station. The individual stacks are each brought into a tilted state in the alignment station by a tilting movement of the alignment station, in which the flat products of a respective stack are displaced parallel to one another. The tilted state of the individual stacks is then released by a return movement of the alignment station opposite to the tilting movement, and the (untilted) individual stacks are picked up again by the robot arm. The individual stacks can be vibrated in the alignment station before being picked up again.

[0005] There are folding carton-gluing machines with inserts for the folding carton blanks to be processed, i.e., for printed and subsequently punched and, if necessary, scored and / or embossed cartons. When the inserts are manually filled, the stack is given a parallelogram-like shape if required.

[0006] Manufacturers of graphic products—for example, printing companies with prepress, actual printing, and postpress—have a constant desire to improve product quality while maintaining or even increasing production speed, which is why robotics is increasingly being used. Furthermore, this can replace unavailable personnel in times of staff shortages. Technical task

[0007] It is therefore an object of the present invention to provide an improvement over the prior art which makes it possible, in particular, to improve the production flow in the manufacture of graphic products, in particular to achieve greater speed and accuracy. Inventive solution to the problem

[0008] This object is achieved according to the invention by a method according to claim 1.

[0009] A method according to the invention for handling stacks of flat products, wherein a robot arm successively picks up individual stacks at an upstream station and wherein the individual stacks are each brought into a tilting state after being picked up, in which the flat products of a respective stack are displaced parallel to one another, is characterized in that the individual stacks are passed on in the tilting state by the robot arm to a downstream station.

[0010] Advantageous and therefore preferred developments of the invention emerge from the subclaims as well as from the description and the drawings. Advantageous embodiments and effects of the invention

[0011] The invention advantageously enables the production flow in the manufacture of graphic products to be improved, particularly by achieving greater speed and accuracy. The invention is used, for example, in the production of folding trays.

[0012] According to the invention, the stack is left in the tilted state it has reached and is passed on in this way, ie the tilted state is not resolved again before being passed on.

[0013] The invention can be used advantageously to tilt stacks of flat products (temporarily) before they are inserted into inserters of further processing machines, i.e., to bring them into the required parallelogram shape. At the same time, high edge accuracy can be achieved. If this is done using a moving alignment device on the robot tool, time can be saved during insertion. If this is done using a stationary alignment device, the tool on the robot can be constructed more easily and the robot movement can be executed more quickly. In both cases, the mobility of the robot can be advantageously used to transfer the stack into the tilted state; additional actuators can then be eliminated. Further developments of the invention

[0014] Preferred developments of the invention (hereinafter referred to as "developments") are described below. These can also be combined with one another where not technically mutually exclusive.

[0015] A further development can be characterized in that the individual stacks, when viewed from one side of the respective stack in the respective tilted state, have the shape of a parallelogram. It can be provided that the flat products of a respective stack are shifted parallel to one another by a predetermined value in the tilted state. This value can be in the range of 0 mm to 25 mm (distance between shifted edges of the products).

[0016] A further development can be characterized in that the robot arm carries a gripper head as a tool. The gripper head is preferably arranged rotatably. The gripper head can comprise a gripping device for gripping the individual stacks. The gripping device can comprise at least two grippers. One of the grippers can be moved relative to the other gripper when the gripping device is opened and closed. The grippers preferably comprise prongs.

[0017] A further development can be characterized in that an alignment device is provided and is thus present. It can be provided that the alignment device comprises at least two stop elements and at least one alignment element. It can be provided that the stop elements are provided as stop rods; these are preferably arranged in one plane. It can be provided that the alignment element is provided as an alignment plate, which is preferably perpendicular to the plane of the stop rods. It can be provided that the flat products of individual stacks are placed upright on the stop elements in the alignment device, ie in particular with their edges on the stop elements. It can be provided that the flat products of individual stacks are placed upright on the stop elements in the alignment device.It can be provided that the flat products of individual stacks are placed on the stop elements in the alignment device at an angle of < 45°. It can be provided that the flat products of individual stacks are placed in the alignment device adjacent to the alignment element, i.e. in particular with their surfaces against the alignment element. Alternatively, it can be provided that the stacks are not placed on the stop elements, but that the stack is moved past the stop elements (and possibly also the alignment element) in contact with them; in the process, the stack is tilted (and possibly aligned).

[0018] A further development can be characterized in that the stop elements and the alignment element are adjusted to the format of the flat products before the individual stacks are set down. It can be provided that the stop elements and / or the alignment element are linearly adjustable in at least one direction. It can be provided that the stop elements and / or the alignment element are adjustable in two mutually perpendicular linear directions; this can be particularly advantageous for folding box blanks with their diverse edge contours. It can be provided that the stop elements and / or the alignment element are tiltable; in particular in the case that the alignment device is provided on the gripper head. It can be provided that the stop elements and / or the alignment element are tiltable by a predetermined tilt angle which defines the tilt state.It may be provided that the stop elements and / or the alignment element are lockable, particularly when a format adjustment has been made. It may be provided that the adjustment and / or tilting of the stop elements and / or the alignment element is motorized and controlled; alternatively, the adjustments are made manually.

[0019] A further development can be characterized by the individual stacks being vibrated in the alignment device. The vibration can be achieved by a vibrating drive or a robot.

[0020] A further development can be characterized in that the alignment device is provided as an alignment station. It can be provided that the alignment station is provided separately from the robot; alternatively, both can form a unit. It can be provided that the robot moves the gripper head with a stack from the upstream station to the alignment station; the upstream station can be a punching press or a printing press with a punching station; alternatively, the upstream station can be a storage area for stacks, e.g. a storage rack with multiple storage locations; alternatively, the upstream station can be a pallet with a pallet stack located thereon and built up according to a depositing pattern from a plurality of (individual or partial) stacks of flat products. It can be provided that the gripper head deposits the stack in an alignment station. It can be provided that the gripper head picks up the stack from the alignment station again.The robot may be arranged to move the gripper head with the stack from the alignment station to the downstream station; the downstream station may be a folder-gluer.

[0021] A further development can be characterized in that the individual stacks are each brought into the tilted state by a tilting movement of the gripper head and / or a tilting movement of the alignment device and by a temporary opening / closing - i.e. first opening and then closing again - of the gripping device. It can be provided that a value for the inclination as a result of the tilting movement is provided as a default value. It can be provided that the value lies in the range from 0° to 30°. It can be provided that a value of a required inclination is determined by a sensor and then provided as a default value; the sensor is preferably arranged on a feeder of the downstream station and measures an inclination set there for the products to be fed to the station. It can be provided that the gripper head is tilted relative to the alignment device during the tilting movement.It can be provided that the alignment device has a longitudinal direction and that the gripper head is tilted about the longitudinal direction. It can be provided that the individual stacks are brought into the tilting state solely by the tilting movement of the gripper head (i.e., without a separate tilting movement of the alignment device) or solely by the tilting movement of the alignment device (i.e., without a separate tilting movement of the gripper head).

[0022] A further development can be characterized by dropping the individual stacks onto the alignment elements as they are set down; preferably only by a few millimeters or a few centimeters, approximately 10 to 20 mm. It can be provided that the gripper head is positioned above the alignment device for the drop, and the grippers of the gripper head are temporarily opened and closed again.

[0023] A further development can be characterized in that the robot arm includes the alignment device. The alignment device can be arranged on the gripper head. Alternatively, the gripper head and the alignment device can form a single unit.

[0024] A further development can be characterized in that the individual stacks are brought into the tilting state by temporarily opening / closing the gripping device. Tilting of the gripping device is not necessary in this case. It can be provided that the gripper head is oriented when opening / closing the gripping device in such a way that the stack remains in the gripping device and is thereby transferred into the tilting state; i.e. that the stack does not fall out of the gripping device and in particular that its tines or loose tine ends point essentially upwards. This type of tilting of the stack can take place at a predetermined alignment point to which the gripper head is moved and at which the gripper head executes its tilting movement.The alignment point can be located spatially and / or (production) process-wise between the upstream and downstream stations; alternatively, the robot can perform a movement towards a "safe" location as the alignment point ("safe" in the sense that the tipping process can be carried out there without endangering personnel and / or causing equipment collisions).

[0025] A further development can be characterized in that the robot arm moves the individual stacks to a feeder of a further processing machine, in particular a folding box gluing machine.

[0026] A further development can be characterized in that a controller, in particular a digital computer, is provided and operated in such a way that the tilt angle is specified; preferably as a fixed default value for the stacks of a sequence of stacks which are transferred to a subsequent station, or alternatively as different default values ​​for the stacks of a sequence of stacks if these stacks are transferred alternately to different subsequent stations.

[0027] The technical features disclosed in the above sections Technical Field, Invention and Further Developments as well as in the section Embodiments can represent further advantageous developments of the invention as those combinations of features which can be derived from this application. Embodiments of the invention and figures

[0028] The Fig. Figures 1 to 5 show preferred embodiments of the invention and its further developments. Corresponding features are provided with the same reference numerals in the figures. Recurring reference numerals have been partially omitted for clarity. Fig. 1 shows a perspective view of a device during implementation of a preferred embodiment of a method according to the invention. Fig. 2 and Fig. 3 each show a corresponding side view. Fig. 4 shows a perspective view of another device when carrying out another preferred embodiment of a method according to the invention. Fig. 5 shows a corresponding side view. Fig. 6 shows a schematic representation of the sequence of a preferred embodiment of a method according to the invention.

[0029] In Fig. 1 shows a robot 1 with a movable and multi-jointed robot arm 2, e.g. a gantry or articulated arm robot (possibly designed as a so-called cobot), which serves or is used in a process-technical manner to move a stack 3 of flat products 4 (compare also the Fig. 2 and Fig. 3). The flat products 4 are preferably folding box blanks made of cardboard and can have different formats 5 from stack to stack, in particular different edge profiles 5a; preferably such profiles as are usual for still unfolded folding box blanks. According to the invention, the stack 3 is brought / transferred into a tilting state 7, in which the stack 3, viewed from one side, preferably has a parallelogram shape 6; preferably from a side in which the edges of the products 4 point. Such a parallelogram shape 6 may be required if a downstream station (cf. Fig. 6) requires the creation of a parallelogram-shaped stack 3 or this is at least advantageous.

[0030] A gripper head 10 is arranged at the end of the robot arm 2 as a (robot) tool, preferably rotatable about a rotation axis parallel to the last link of the arm. The gripper head 10 comprises a gripping device 11 with a first gripper 12 having a plurality of prongs 12a and a second gripper 13 having a plurality of prongs 13a. The second gripper 13 is movable (back and forth; see movements 50) in the direction of the first gripper 12 for gripping and releasing, for which purpose at least one drive 14 is provided, preferably a controlled, electric linear drive.

[0031] In Fig. 1 also shows an alignment device 20 with a frame 21, a longitudinal direction 22a, a transverse direction 22b, and a vertical direction 22c. The alignment device 20 comprises stop elements 23; two such elements are shown as movable and lockable rods, for example, and an alignment element 24; one such element is shown as a plate, for example. The stop elements 23 are arranged on guides 25 and can be moved separately and finally locked thereon, whereby the guides 25 themselves are arranged on the frame 21 and can be moved separately and finally locked thereon. The stop elements 23 can thus be individually adjusted to the format 5, in particular to the format-dependent edge profile 5a (see movements 60). The adjustment movements can be effected by one or more motors 26, as can the locking mechanism.A vibrating device 27 can be arranged on the frame 21, which temporarily vibrates the frame and thus also the stop elements 23 and the alignment element 24, whereby the individual flat products 4 in the stack 3 are supported during the striking and / or alignment of the stack 3.

[0032] A comparison of the Fig. 1 to 3 show how the stack 3 is brought into the tilted state 7 by a tilting movement 40 of the gripper head 10. The individual products 4 remain in contact with the stop elements 23 with their (lower) edges, and the stack 3 remains in contact with the alignment element 24 with one of its sides or with a product 4; the individual products 4 are displaced relative to one another by the tilting of the gripping device 11 - preferably with the prongs 12 or 13a only slightly open (this creates a mutual offset of adjacent products 4 in one direction), and the parallelogram shape 7 is created; the tilted stack 3 is securely gripped again and can then be moved in the tilted state 7 according to the invention. The tilt angle 70, i.e., the angle by which the stack 3 is tilted, can be predetermined by the control system and can be generated by a corresponding movement 40 of the robot arm 2 or the gripper head 10.Alternatively, the alignment device 20 could be tilted by the tilt angle (preferably with the tines only slightly opened); or only its stop elements 23; a tilt drive could be provided for this purpose.

[0033] In Fig. 4 is also a robot 1 with a movable and multi-jointed robot arm 2 indicated in end sections, which - comparable to that in Fig. 1 - serves or is used in a process-technical manner to move a stack 3 of flat products 4 (compare also Fig. 5). The flat products 4 are also preferably folding box blanks. According to the invention, the stack 3 is also brought / transferred into a tilted state 7, in which the stack 3, viewed from one side, preferably has a parallelogram shape 7.

[0034] At the end of the robot arm 2 there is a gripper head 10 - comparable to that in Fig. 1 - arranged. The gripper head 10 comprises as in Fig. 1 shows a gripping device 11 with a first gripper 12 with prongs 12a and with a second gripper 13 with prongs 13a. The second gripper 13 is movable (back and forth) in the direction of the first gripper 12, for which purpose a drive 14 is provided, preferably a controlled, electric linear drive.

[0035] In Fig. 4 also shows an alignment device 20. In contrast to Fig. 1, the alignment device 20 is part of the gripper head 10, ie arranged on it or integrated into it. The alignment device 20 comprises - comparable to that in Fig. 1 - Stop elements 23, two such elements are shown as movable and lockable rods by way of example, and an alignment element 24, one such element is shown as a plate by way of example. The stop elements 23 are arranged on guides 25 and can be separately displaced and tilted thereon, as well as finally locked. The guides 25 themselves are arranged on the gripper head 10 or on its frame 10a and can be separately displaced and finally locked thereon. The stop elements 23 can thus be individually adjusted to the format 5 and to a predetermined tilt angle 70 (see movements 61). The alignment element 24 shown can also be correspondingly displaced and optionally tilted and finally locked. The adjustment movements can be effected by one or more motors 26, as can the locking mechanism.

[0036] The Fig. 4 and Fig. 5 show how the stack 3 is brought into the tilted state 7 by temporarily opening and closing the gripping device 11; the opening and closing preferably takes place at a predetermined alignment point 31a. Preferably, the gripper head 10 is moved and oriented such that the stack 3 is positioned at the top in the gripping device 11 or that the gripper head 10 is located substantially beneath the stack 2 (the prongs are adjacent to the stack 3). Then, the gripping device 11 or the prongs 12a and 13a are temporarily opened and closed again for a short time, causing the individual products 4 to fall downwards a short distance. The individual products 4 come into contact with the tilted stop elements 23 with their (lower) edges, and the stack 3, with one of its sides or with a product 4, comes into contact with the alignment element 24; the individual products 4 are thereby tilted or displaced relative to one another, creating the parallelogram shape 7.If shaking is required, this can preferably be done by the robot 1 or by a shaking device on the gripper head 10. Alternatively, it could be provided to tilt not the stop elements 23, but the tines 12a and 13a.

[0037] In Fig. 6, the robot 1 is shown centrally, including the robot arm 2 and the gripper head 10. Upstream in the production flow (in the figure on the left) is a station 30 with a boom 30a; alternatively, for example, a shelf or a pallet for stack 3. There, the gripper head 10 takes over one stack 3 at a time and moves it to the alignment station 31 (movement 62; compare also Fig. 1 to 3); alternatively to alignment point 31a (compare Fig. 4 and Fig. 5). There, in turn, either a tilting movement 40 of the gripper head 10 takes place (compare Fig. 1 to 3) or a tilting movement 41 of the alignment device 20 (compare Fig. 4 and Fig.5); the stack 3 thereby enters the tilted state 7. The gripper head 10 then moves the stack 3 in the existing and maintained tilted state 7 from location 31 (or 31a) to a downstream station 32 in the production flow (on the right in the figure) with a feeder 33 for tilted stacks 3 (movement 63) and deposits the tilted stack 3 there. A sensor 34 can be arranged on the feeder, which determines a tilt angle required for problem-free insertion and transmits this as a default value to a controller 71 (or a corresponding digital computer) for controlling the method sequence according to the invention, in particular the tilt angle 70. Finally, the gripper head 10 is moved back to the upstream station 30 (movement 64); the described cycle can then be continued with at least one further stack 3. List of reference symbols 1 robot 2 robot arm 3 stacks 4 flat products, especially folding box blanks 5 Format 5a Edge progression 6 Parallelogram shape 7 Tilt state 10 Gripper head 10a frame 11 Gripping device 12 first gripper 12a first prongs 13 second gripper, movable 13a second prong 14 Drive(s) for opening and closing the gripping device 20 Alignment device 21 frame 22a Longitudinal direction of the alignment device 22b Transverse direction of the alignment device 22c Vertical direction of the alignment device 23 stop elements 24 Alignment element 25 guided tours 26 engines 27 Vibrating device 30 upstream station (machine or warehouse or pallet) 30a boom 31 Alignment station 31a Alignment point 32 subordinate station (machine) 33 inserts 34 Sensor 40 Tilting movement (gripper head) 41 Tilting movement (alignment device) 42 Inclination due to the tilting movement 50 movements when opening and closing the gripping device 60 first adjustment movements (stop elements, alignment element) 61 second adjustment movement(s) (stop elements, alignment element) 62 Movement from upstream station to alignment station 63 Movement from alignment station to downstream station 64 Movement from downstream station to upstream station 70 tilt angle 71 Control QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 102023124557A1

[0003] US 2018366766A1

[0004]

Claims

[1] Method for handling stacks of flat products, wherein a robot arm (2) successively picks up individual stacks (3) at a pre-arranged station (30) and wherein the individual stacks (3) are each brought into a tilting state (7) after being picked up, in which the flat products (4) of a respective stack (3) are displaced parallel to one another, characterized by that the individual stacks (3) in the tilting state (7) are passed on by the robot arm (2) to a downstream station (32). [2] Method according to claim 1, characterized by that the robot arm (2) carries a gripper head (10) as a tool. [3] Method according to claim 2, characterized by that the gripper head (10) comprises a gripping device (11) for gripping the individual stacks (3). [4] Method according to one of the preceding claims, characterized by that an alignment device (20) is provided. [5] Method according to claim 4, characterized bythat the alignment device (20) comprises at least two stop elements (23) and at least one alignment element (24). [6] Method according to claim 5, characterized by that the stop elements (23) and the alignment element (24) are adjusted to the format (5) of the flat products (4) before the individual stacks (3) are deposited. [7] Method according to one of the preceding claims, characterized by that the individual stacks (3) are shaken in the alignment device (20). [8] Method according to one of the preceding claims, characterized by that the alignment device (20) is provided as an alignment station (31). [9] Method according to claim 8, characterized by that the individual stacks (3) are each brought into the tilting state (7) by a tilting movement (40) of the gripper head (10) and / or a tilting movement (41) of the alignment device (20) and by a temporary opening / closing (50) of the gripping device (11). [10] Method according to claim 9, characterized by that a value for the inclination (42) as a result of the tilting movement (40, 41) is provided as a default value. [11] Method according to one of the preceding claims 8 to 10, characterized by that the gripper head (10) is tilted relative to the alignment device (20) during the tilting movement (40, 41). [12] Method according to one of the preceding claims 8 to 11, characterized by that when the individual stacks (3) are placed down, the stacks (3) are dropped onto the alignment elements (23). [13] Method according to one of the preceding claims 1 to 7, characterized by that the robot arm (2) comprises the alignment device (20). [14] Method according to claim 13, characterized by that the alignment device (20) is arranged on the gripper head (10). [15] Method according to claim 14, characterized bythat the individual stacks are brought into the tilting state (7) by a temporary opening / closing (50) of the gripping device (11). [16] Method according to claim 15, characterized by that the gripper head (10) is oriented during opening / closing (50) of the gripping device (11) such that the stack (3) remains in the gripping device (11) and is thereby transferred into the tilting state (7).

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