Method and apparatus for handling a stack of leaf-shaped material

Abstract

Method for handling a stack (10) of sheet-shaped goods, in particular a stack of securities sheets, comprising the process steps, - Aligning the stack in a first state with a cutting line of a cutting blade of a cutting device (14), - Grasping the stack and aligning the stack in a second state onto the cutting line and cutting the stack, wherein the stack is grasped by means of at least one gripping element (38, 40) for aligning the stack, wherein the stack (10) is acted upon by a pressure element (28) during cutting while the at least one gripping element (38, 40) is simultaneously ineffective and the pressure element is spaced apart from the stack during the alignment of the stack while the stack is simultaneously grasped by means of the at least one gripping element, characterized by that at least one gripping element (38, 40) is actuated by the pressure element (28), which in turn exerts force over the entire surface of the stack so that the sheets do not shift during cutting.

Description

[0001] The invention relates to a method for handling a stack of sheet-shaped goods, in particular a stack of securities sheets, comprising the method steps - Aligning the stack in a first state with a cutting line of a cutting blade of a cutting device and cutting the stack, - Grasping the stack and aligning the stack in a second state onto the cutting line and cutting the stack, wherein the stack is grasped by means of at least one gripping element for aligning it, wherein the stack is acted upon by a pressure element during cutting while the at least one gripping element is simultaneously ineffective, and the pressure element is spaced away from the stack during the alignment of the stack while the stack is grasped by means of the at least one gripping element.

[0002] The invention also relates to a device for handling a stack of sheet-shaped material, in particular a stack of security sheets, comprising a robot arm and a device for capturing, moving and / or aligning the stack to a cutting line of a cutting device, wherein the device comprises a pressure element for applying pressure to the stack and at least one gripping device.

[0003] High precision is required, particularly for cutting sheets of securities. To ensure this, WO 2021 / 047869 A1 proposes that the stack be continuously gripped by handling devices, both during movement and cutting. However, a disadvantage is that the pressure exerted on the stack by the handling devices over a relatively small area can lead to undesirable deformation of the stack of printed sheets. This can occur particularly with securities.

[0004] The gripping means can originate from a robot that maintains different distances to the cutting line according to the cutting progress, so that, in principle, a continuous check must be carried out to ensure that the stack is properly aligned with the cutting line in order to achieve precise cuts.

[0005] A cutting system according to DE 195 15 705 C1 has 3 cutting devices, wherein in one cutting device a circumferential cut is carried out and in the other cuts in different directions are carried out.

[0006] German patent DE 10 2020 108 423 A1 describes a device and a method for performing cutting operations in the area of ​​the open edges of printed products. A gripper aligns a printed product with a cutting line, whereby a pressure bar acts on the printed product during cutting while the gripper is slightly open.

[0007] To handle a stack of leaf-shaped material, DE 10 2020 111 448 A1 provides a device extending from a robot arm, which has a gripper for grasping a stack and an aligner by means of which pressure can be applied to the edge of the stack.

[0008] The JP 2020-132381 A is a device for gripping, holding and clamping brochures.

[0009] The present invention is based on the objective of further developing a method and an arrangement of the type mentioned at the outset in such a way that stacks of sheet-shaped material can be cut with high precision, whereby deformations of the stack are to be avoided, in particular when holding the stack during cutting.

[0010] The process of aligning the stack with the cutting line after cuts have been made should also be simplified.

[0011] The problem is essentially solved procedurally by the fact that at least one gripping element is actuated from the pressure element, which in turn exerts force over the entire surface of the stack so that the sheets do not shift during cutting.

[0012] The first state can be that in which the stack is aligned with the cutting line to make an initial cut. The second state can be that in which a cut is made along a different cutting line. In other words, "state" means that the stack is positioned in the desired position relative to the cutting line.

[0013] In particular, it is intended that a planar element, such as a plate element, is used as the printing element, which is handled by a handling device, such as a robot arm.

[0014] According to the invention, when cutting the stack, force is applied over a surface area to the stack, rather than clamping at the edges as is the case in the prior art. This ensures that sufficient pressure can be applied to the stack to prevent the sheets from shifting during cutting. At the same time, deformation is avoided because the pressure is applied over a surface area.

[0015] It is specifically designed that the pressure element is variable in its width and / or length, so that it can be adapted to the surface area of ​​the stack, particularly depending on the cutting progress. Furthermore, the stack can be moved towards the cutting line in the usual way using at least one gripping element, without the pressure element causing any obstruction.

[0016] According to the invention, a single alignment of the stack's orientation to the cutting line is essentially sufficient. Switching between applying pressure via the pressure element and gripping the stack via the at least one gripping element can be achieved with simple structural measures.

[0017] The pressure element serves as a holder for at least one gripping element, so that there is a clear spatial relationship between the pressure element and the gripping element, and consequently, frequent remeasuring or readjustment to align the stack with the cutting line is not necessary, as is the case with the prior art.

[0018] For this purpose, a robot arm is additionally provided for as the handling device. The arm of this robot arm is connected to the pressure element at an edge facing the cutting line. This minimizes the distance between the point of contact of the robot arm on the pressure element and the cutting line, ensuring high precision during the alignment and subsequent cutting of the stack. Simultaneously, the distance between the point of contact of the robot arm and the cutting line, relative to the plane spanned by the stack, remains constant regardless of the cutting progress, thus eliminating the need for readjustment and remeasurement.

[0019] According to the invention, when cutting several strips along parallel cutting lines, the position of the printing element in relation to the plane spanned by the stack can remain unchanged, so that a single alignment is basically sufficient to then cut the desired number of strips.

[0020] An unchanged position within the meaning of the invention is also given if the area of ​​the pressure element is reduced depending on the progress of the cutting, since the position of the robot arm in relation to the plane spanned by the stack remains unchanged, even though the pressure element is raised and lowered; because when the stack is moved in relation to the cutting line, the pressure element is spaced away from the stack, whereas during the cutting itself, the pressure element acts on the stack and the at least one gripping element is ineffective, i.e., the stack cannot be moved by the at least one gripping element.

[0021] In particular, it is provided that the stack is gripped by two gripping elements, such as pliers each having a lower and upper jaw.

[0022] A device of the type mentioned above is characterized in particular by the fact that the gripping device is adjustable relative to the pressure element by means of a drive emanating from the pressure element and that the pressure element is designed to be lowered to apply pressure to the stack surface.

[0023] In particular, it is provided that the pressure element is or comprises a plate-shaped element which acts on the stack, from which at least one drive element, such as a spindle, extends to adjust the at least one gripping element to the pressure element.

[0024] In particular, it is provided that a drive, such as a spindle, for each gripping element, such as a pair of pliers having a lower and upper jaw, originates from opposite parallel edge areas of the pressure element.

[0025] In order to be able to apply pressure to stacks of different surface areas with one and the same device, or to be able to reduce the size of the printing element depending on the course of the cuts, it is provided that the printing element is designed to be variable in width and / or length, in particular when viewed in relation to the plane spanned by the stack.

[0026] It should also be emphasized that the robot arm is connected to the printing element in an area that runs along the edge of the printing element facing the cutting line. This ensures simple yet highly precise alignment with the cutting line.

[0027] The gripping element itself should be pneumatically or electromechanically actuated in order to grasp the stack when moving it on the rear table of a cutting machine and to release the stack when cutting.

[0028] Further details, advantages and features of the invention will become apparent not only from the claims and the features to be derived therefrom - individually and / or in combination - but also from the following description of a preferred embodiment.

[0029] They show: Fig. 1 a robot with printing element and gripping elements, Fig. 2 a cutting system with two robots, Fig. 3 the cutting system according to Fig. 2 in top view, Fig. 4 a second robot with strips of a stack and Fig. 5 a pair of pliers.

[0030] The invention is explained with reference to the figure, according to which a stack of 10 sheet-shaped materials, in particular in the form of securities sheets, can be cut into strips and these into blanks. The term stack also includes a layer of a stack that is to be cut. In this respect, stack and layer can be understood as synonyms in the context of the invention.

[0031] A cutting system 12 can be used for cutting, which in the exemplary embodiment has two cutting devices 14, 16, each with a portal 18, 20, in which cutting blades are arranged vertically and adjustably, each generating a cutting line. The first cutting device 14 cuts the stack 10 into strips 46, 47, 49, 51, 53, and the second cutting device 16 cuts the strips 46, 47, 49, 51, 53 into the respective blanks 42, 44.

[0032] To properly align the stack 10 with the (first) cutting line of the first cutting device 14, a first multi-axis robot 22 with a robot arm 24 is used, at the end of which a pressure element 28 in the form of a plate is attached via a flange 26, which can be lowered onto the stack 10 in the manner described below.

[0033] Spindle drives 34, 36 extend from the pressure element 28, which is designed as a plate, specifically from its opposite edges 30, 32 and edge regions, for gripping elements designed as clamps 38, 40, which can be aligned to the stack 10 as required. The clamps 38, 40 adjust the stack 10 relative to the plate 28 and to the cutting line of the cutting device 14 in order to cut strips 46, 47, 49, 51, 53, each containing a blank 42, 44, after the stack 10 has been properly aligned with the first cutting line. These strips are then cut into the individual blanks 42, 44 in the second cutting device 16. A second multi-axis robot 50 is used for this purpose, the robot arm 52 of which is connected via a flange 54 to a carrier 55 of a gripping device 57.

[0034] In the exemplary embodiment, the carrier 55 has two jaws 66, 68, with a lower jaw 58, 60 and an upper jaw 62, 64, which is adjustable to the respective lower jaw 58, 60.

[0035] To align the stack 10 with the cutting line of the first cutting device 14, the position of the stack 10 is optically detected using markings on the arc of the stack 10 (not shown in the figures). The leading edge of the previously trimmed stack 10 is then aligned parallel to the cutting line of the cutting device 14. For this purpose, the stack 10 is moved on the rear table 98 of the cutting system 12, which includes the cutting device 14, by means of the clamps 38, 40. The plate 28 is spaced apart from the stack 10. To enable this, the spindle drives 34, 36 are pivotally connected to the plate 28.After the stack 10 has been properly aligned and transported through the cutting line to cut a strip of a predetermined width, the pressure element 20 is lowered to exert pressure on the stack 10 to prevent slippage. Simultaneously, the grippers 38 and 40 are disengaged, meaning that there is no longer a functional connection with the stack 10. Nevertheless, a clear spatial relationship between the grippers 38 and 40 and the plate 28 is maintained. After a strip has been cut, it is gripped by the double gripper 57 and fed to the second cutting device 16. It is possible to first arrange several strips 46, 47, 49, 51, and 53 on the rear table 100 in front of the second cutting device 16, and then cut them into blanks.At the same time, further strips can be cut from stack 10, so that an overlap of the work processes cutting the strips and cutting the benefits of cut strips can be achieved, with the result that a higher throughput can be achieved compared to known designs.

[0036] To adjust the printing plate 28 to different widths, its width can be variable. Length adjustability is also possible, if necessary. Regardless, the spindle drives 34 and 36 always run parallel.

[0037] The grippers 38, 40 themselves can be pneumatically actuated, e.g. via pressure lines running along the robot arm 24, or electromechanically, in order to grip or release the stack 10 to the required extent.

[0038] The tongs 38, 40 can move the stack on the rear table 98 with little force and act as a stop when pushing towards the first cutting line, so that deformations of the sheet-shaped material by the tongs 38, 40 are excluded. List of reference symbols: 10 stacks 12 cutting system 14 Cutting device 16 Cutting device 18 Portal 20 Portal 22 robots 24 robot arm 26 flange 28 Pressure element 30 Rand 32 Rand 34 Spindle drive 36 spindle drive 38 Pliers 40 pliers 42 Benefits 44 Benefits 46 strips 47 stripes 49 strips 50 multi-axis robots 51 strips 52 robot arm 53 strips 54 flange 55 carriers 57 Gripping device 58 Lower jaw 60 lower jaw 62 Upper cheek 64 Upper cheek 66 Pliers 68 Pliers 98 Back table 100 back table

Claims

[1] Method for handling a stack (10) of sheet-shaped material, in particular a stack of security sheets, comprising the method steps, - aligning the stack in a first state with a cutting line of a cutting blade of a cutting device (14), - grasping the stack and aligning the stack in a second state to the cutting line and cutting the stack, wherein for aligning the stack, the stack is grasped by means of at least one gripping element (38, 40), wherein the stack (10) is acted upon by a pressure element (28) during cutting while the at least one gripping element (38, 40) is simultaneously ineffective, and the pressure element is spaced from the stack during alignment of the stack while simultaneously grasping the stack by means of the at least one gripping element, characterized by , that the at least one gripping element (38, 40) is actuated by the pressure element (28), which in turn applies a force to the stack surface over a large area so that the sheets are not displaced during cutting. [2] Method according to claim 1, characterized by that a flat element, such as a plate element, is used as the pressure element (28), which is handled by a handling device (22), such as a robot. [3] Method according to claim 1 or 2, characterized by that the stack (10) is gripped by two gripping elements (38, 40), each of which is a pair of pliers having a lower jaw (58, 60) and an upper jaw (62, 64). [4] Method according to at least one of the preceding claims, characterized by that the pressure element (28) is designed to be variable in its width and / or length. [5] Method according to at least one of the preceding claims, characterized bythat the handling device (22) is a multi-axis robot and is connected via its arm (24) to the printing element (28) in an edge region of the printing element which faces the cutting line. [6] Method according to at least one of the preceding claims, characterized by that the distance between the connection point of the robot arm (24) and the cutting line remains constant when cuts are carried out one after the other, viewed in the plane spanned by the stack (10). [7] Device for handling a stack (10) of sheet-shaped material, in particular a stack of security sheets, comprising a robot arm (24) of a robot (22), with a device (38, 40) for detecting, displacing and / or aligning the stack with respect to a cutting line of a cutting device (14), wherein the device comprises a pressure element (28) applying pressure to the stack (10) and at least one gripping device (38, 40), characterized bythat the gripping device (38, 40) is adjustable relative to the pressure element (28) via a drive (34, 36) emanating from the pressure element (28) and that the pressure element (28) is designed to be lowerable for applying pressure to the stack surface. [8] Device according to claim 7, characterized by that the pressure element (28) is a plate-shaped element from which the drive element (34, 36), such as a spindle, extends. [9] Device according to claim 7 or 8, characterized by that from opposite, preferably mutually parallel, edge regions (30, 32) of the pressure element (28) a drive (34, 36), such as a spindle, for a respective gripping device (38, 40), such as a pair of pliers having a lower and upper jaw (59, 60, 62, 64), emanates. [10] Device according to at least one of claims 7 to 9, characterized by that the pressure element (28) is designed to be variable in width and / or length. [11] Device according to at least one of claims 7 to 10, characterized by that the robot (22) or its arm (24) is connected to the pressure element (28) in an area which runs in the edge area of the pressure element facing the cutting line.

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