EP2841368A1

EP2841368A1 - Gripping device for gripping sheets

Info

Publication number: EP2841368A1
Application number: EP13718129.3A
Authority: EP
Inventors: Markus Sperl; Erwin Demmeler; Frank Werner
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2012-04-25
Filing date: 2013-04-22
Publication date: 2015-03-04
Anticipated expiration: 2033-04-22
Also published as: RU2614366C2; CN104245553B; WO2013159900A1; DE102012008242A1; CN104245553A; CN106966216B; CN106966216A; US9573787B2; RU2014147074A; US20150093230A1; KR20140133595A; KR101641012B1; EP2841368B1

Abstract

The present invention relates to a gripping device for gripping a stack of sheets (1). The gripping device has at least two gripping elements (21, 41), which are intended for gripping a stack of sheets arranged between the gripping elements and can be moved towards one another in order to grip the stack of sheets. At least one of the gripping fingers (22) of one of the gripping elements can be tilted from its starting position, in which it is oriented substantially parallel to the stack surface, into a tilted position, in which it is inclined in the direction of the stack surface. The gripping device can be used to remove any desired types of sheet stack reliably and straightforwardly from a container, and to retain the same by clamping action counter to gravitational force.

Description

Gripping device for gripping sheet material

The present invention relates to a gripping device and a method for gripping sheet material, in particular a sheet stack, and a device having the gripping device. In order to transport a stack of sheet material from a home position to a target position, stationary transport means are known which convey the entire stack from a home position to a destination position. Alternatively, it is also known to subtract at the starting position, the individual sheets one after the other from the stack of sheets and convey to the target position and there, if necessary, to re-stack. Since such devices are laborious and inflexible with respect to a variable starting and ending position, in some applications the respective sheet stack is manually transported by a person. Instead of manual transporting, however, it is also known to use a gripper which can grasp the sheet material stack and transport it to the destination position. The gripper compresses the stack of sheet material at its top and bottom sides in order to achieve gripping clamping of the sheet material stack. In particular, such grippers can be used to remove a sheet material stack from a container and to deposit the removed sheet material stack at a desired target position.

For the processing of value documents, for example, containers are used which are obvious on one page or are permanently open, and into which one or more value document stacks can be inserted from loose value documents. In order to remove the value documents, the container is usually arranged so that its open side points upward and the value documents in the container stand on their longitudinal edges. If a plurality of value document stacks are to be kept separate from one another in the container, for example in order to be able to differentiate the stacks from one another, the container can be provided with dividing elements which subdivide the container into a plurality of partial regions, cf. Figure la. Both the inner wall of the container and the separating elements usually have a meandering surface of a plurality of projections and recesses on their sides facing the value document surfaces. In order to remove the value-document stack by a gripper automatically from the container, a gripper with several gripping fingers can be used, which dip from above into the recesses of the meander-shaped surface. Accordingly, the recesses of the container and the gripper fingers of the gripper are adapted to each other in their arrangement and size. The gripper has, for example, two rake-like gripping elements of a plurality of gripper fingers, which can be moved toward and away from each other to grip the document of value as soon as the gripping fingers are immersed vertically in the recesses of the container. With the help of the gripper so the desired document of value stack can be grasped, taken from the container and stored away from the container or inserted into a device for value document processing.

A trouble-free removal of a stack of sheets from the container succeeds in this way, however, only in those sheet stacks in which the number of sheets is not too large. Because large stacks are prone to fall out of the Greifklemmung the gripper when removing the stack due to their larger mass and unfavorable geometry. In addition, it is particularly difficult to safely remove mixed stacks of sheet material of various sizes, as this leads to uneven mechanical properties of the sheet material stack. Another difficulty arises from the fact that the force exerted by the gripper on the stack surface In order to hold the stack against gravity and acceleration forces, it depends on the friction between the gripper and the sheet on the stacking surface and on the friction between the sheets of the stack, and these frictional forces, depending on the type and condition of the blades vary. So far, therefore, a secure and trouble-free removal of sheet stacks is therefore possible only for certain types of sheet stacks.

The object of the present invention is to provide an improved solution for this, to remove a stack of sheets in a container by means of a gripper from the container and hold by Greifklemmung against gravity.

This object is solved by the features of the independent claims. Further advantages of the present invention will become apparent from the dependent claims.

In the case of very large stacks of sheet material, it has been observed that the force required for gripping must be chosen so large that the gripping fingers can be elastically bent by the counterforce of the stack. Due to the bending of the gripper fingers outwards, the gripping force acts above all only on the edge of the sheet material, so that the sheet material stack can fall out of the gripping clamp. The gripping device according to the invention has at least two gripping elements for gripping a sheet material stack arranged between the gripping elements. The gripping elements can be moved toward each other to grip the sheet stack and move away from each other to release the sheet stack. One of the gripping elements can be be formed weglich and the other stationary or both can be designed to be movable. In order to achieve gripping clamping of the stack of sheets at both ends of the stack, the gripping device grips the stack by compressing the stack at both ends of the stack in the direction of the stack. The gripping elements each have at least one gripping finger. The gripping fingers can be applied to the stack end sheet of the sheet material stack to be gripped, which is located at the respective gripping element facing the end of the stack of sheets. According to the invention, at least one of the gripping fingers of one of the gripper elements is tiltable from its initial position, in which it is oriented essentially parallel to the surface of the stack end sheet facing it, into a tilted position, in which it is inclined towards the surface of the stack end sheet facing it. Preferably, all gripping fingers of at least one of the gripping elements are designed to be tiltable. The second gripping element may also have tiltable gripping fingers.

In the starting position, in which the tiltable gripping finger is not tilted, it can dip vertically into the recesses of a meander-shaped surface of the side wall of a container. This is advantageous over permanently tilted gripper fingers, since these, if they should dive into such recesses, would require more space due to the tilted position, which would be at the expense of recordable in the container Blattgutmenge. The inventive tilting of the gripper finger displaces the point at which the gripping force of the gripper finger acts largely on the stack of sheets on a gripping point, which is no longer at the edge, but especially in the middle region of the sheet material stack. The tilting of the gripper finger acts a decreasing Greifklemmung, by the elastic bending of the Greiffingers arises, contrary. This allows a secure gripping and transporting very large stacks of sheets and mixed stacks of different sized sheets. However, the gripping device according to the invention can be used very flexibly, which concerns the sheet material stack to be gripped. Because with the same gripping device, without making a change in the gripping device, both a very large stack of sheets and a stack of very few individual sheets or even a single sheet can be safely removed from a container. Preferably, each gripping element in each case has at least two gripping fingers which run parallel to one another and are arranged at a distance from one another. The gripping elements are in particular positioned relative to each other such that the gripping fingers of the gripping elements are arranged offset from one another, ie the gripping fingers of one of the gripping elements each coincide with the gaps which lie between the gripping fingers of the other gripping element. The one or more tiltable gripping fingers of the gripping element are tilted so that in their tilted position they exert gripping clamping on the stack, which is sufficient to hold the sheet material stack against its gravitational force, and in particular also against the acceleration forces required to transport the sheet material stack. The tilting causes the stack of sheets to be held solely by the gripping clamp, without the sheet stack of its underside being supported against gravity, ie without the stack resting on a support. The gripping device is movable in space and therefore set up for transporting a sheet stack from a starting position to a target position. For this purpose, the gripping device can be fastened, for example, to the articulated arm of an articulated arm robot, in order to enable three-dimensional movements of the gripping device in space (translational and rotational movements). conditions). For example, the gripping device can be used to remove a stack of sheets from a container and store the removed sheet stack at a desired destination position again. Alternatively, it is possible with the help of the gripping device and removal of a stack of sheets from any tray or from an output tray of a Blattgutbearbeitungsvorrichtung.

The respective tiltable gripping finger is tiltable about an axis which is oriented approximately parallel to the surface of the gripping finger zugewandte Stapelendblatts and which includes a non-zero angle with the direction of the gripper finger, which is for example 90 ° or approximately at 90 °. The gripping finger is tiltable such that, in its tilted position, it is inclined along the direction perpendicular to the surface of the stack end blade facing it (also referred to below as the "stack surface") The outer end of the tiltable gripper finger, that of the attachment In the tilted position, the outer end of the tiltable gripper finger is relative to those portions of the tiltable gripper finger which are closer to the attachment of the tiltable gripping finger to the gripping member than the tilted gripper finger However, in the initial position of the tiltable gripper finger, the outer end of the tiltable gripper finger and the portions of the tiltable gripper finger closer to the attachment of the tiltable gripper finger to the gripping member than the outer end are along the direction perpendicular to St apel surface the same position. In its initial position, the gripping finger can be applied in particular to the stack end sheet such that the gripping finger contacts the stack end sheet over at least a quarter of the length of the stack end sheet, preferably over at least half the length, with the length of the stack end sheet in the direction in which the gripping finger points. With respect to its initial position, the gripping finger assumes a sharp tilt angle in its tilted position. This acute tilt angle is in particular 1 ° - 20 °, for example 2 ° -5 °.

By tilting the tiltable gripping fingers is achieved that the gripping force exerted by the tiltable gripper finger in its tilted position on the sheet stack, is exerted mainly by the outer end of the tiltable gripper finger on the Blattgutstapel, by the attachment of the tiltable gripping finger the gripping element is remote. In the tilted position, the outer end of the tiltable gripper finger exerts the gripping force on the stack of sheets on a gripping put on the Stapelendblatt, which is not in the edge region, but in the middle region of the sheet material stack. The center region of the sheet material stack is that region which, viewed along the direction of the gripper finger, removes at least 30% of the width of the sheet material stack from both edges of the sheet material stack which the sheet material stack has in the direction of the gripper finger. Preferably, the gripping point along this direction is approximately in the middle of the sheet material stack. The gripping point at which the gripping finger essentially holds the stack of sheets in its tilted position is, for example, a point of contact, wherein, due to the elasticity of the sheet material stack, but also in the tilted position, a surface contact of the stack end sheet by the gripper finger is possible. The advantage of gripping clamping in the center region is that neither the gravity nor the inertia of the stack (when the stack moves in space) can impart torque to the stack when transporting the stack of sheets through the gripper, regardless of direction, such as the stack is held. It is particularly advantageous if at least one of the gripping elements has at least two of the abovementioned tiltable gripper fingers, which are located on both sides of the center of the sheet material stack are arranged, in particular, which are arranged approximately symmetrically to the center of the sheet material stack. In each case the outer end of the tiltable gripping finger exerts in its tilted position a gripping force on the stack of sheets at a gripping point in the middle region of the sheet material stack. The two gripping points are arranged on both sides of the center of the sheet material stack, they are preferably symmetrical to the middle of the sheet material stack. In the case of a mixed sheet stack with sheets of different sizes, which are aligned on one side, on the same sheet edge, the gripping points of the gripping fingers are preferably selected symmetrically to the center of the smallest sheet of the sheet material stack.

In an improved embodiment, at least the gripping fingers of one of the gripping elements are designed for a compensating movement, which allows an adaptation of the position of the gripping fingers to uneven stacked sheets. This may be the same gripping element, which also has the / the tiltable gripping finger and / or the other gripping element that has no tiltable gripping fingers. For the compensating movement, the gripping fingers are fastened to the gripping element in such a way that, relative to the gripping element, they can be moved into different positions along the direction perpendicular to the stacking surface of the sheet material stack. The trained for compensating movement gripping fingers are attached to the gripping member that they are relative to the gripping element along the direction perpendicular to the stack surface against a spring force deflected. The fact that the two gripping fingers are movable perpendicular to the stack surface in different positions, the position of each of the gripper fingers automatically adapts to a locally different large opposing force of the gripped sheet stack, which is different sizes at different locations along the stack surface. This compensatory movement of the gripper fingers is depending on the above tilting movement for tilting the gripper fingers.

The mobility of the gripper fingers in different positions perpendicular to the banknote stack causes the position of the respective gripper finger, this element, at the time of Greifklemmung the stack, relative to the gripping element eiruümmt, depending on the local stack height and / or depending on the local mechanical properties of the stack is variable. By this compensating movement of the gripper fingers is avoided that the gripping force distributed very differently to the gripper fingers. Without the compensating movement, the gripper finger, which engages in the area of greater stack height, would eliminate a very large portion of the gripping force, while the gripper finger, which grips in the area of lower stack height, would eliminate a low gripping force. If the force distribution differs greatly, there is a risk that the stack will slip out of the gripping clamp of the other gripper finger under the influence of gravity and the stack will be rotated by the resulting torque around the gripping point of the first-mentioned gripper finger. The compensating movement of the gripping fingers ensures that the gripping force of the gripper fingers exerted for gripping clamping is matched to one another when a banknote stack with locally different stacking height and / or locally different mechanical properties is gripped. For example, the two gripper fingers approximately exert the same force on the stack. This also uneven sheets stacks can be used safely.

For example, the two gripping fingers of the gripping element are formed by a fork, which is rotatable about an axis, which is oriented approximately parallel to the gripper fingers to enable the compensating movement and in particular approximately on the perpendicular bisector between the two gripping fingers. likes to lie. When turning the fork about the axis, the gripper fingers move in opposite directions. When one of the gripping fingers is deflected away from the stacking surface, the other gripping finger is automatically deflected counter to the stacking surface. The rotational movement about the axis of the fork of the gripper finger counteracts a spring force.

The gripping device preferably has a stop mechanism for switching off the drive, which drives the relative movement of the gripping elements, and thus for automatically stopping the relative movement of the gripping demente, as soon as a generated during the Greifklemmung counterforce of the sheet material stack exceeds a certain value. This ensures that a predefined gripping force of the gripping device acts on the sheet material stack, which is sufficient to grasp the stack safely, but not to damage. In one embodiment, the gripping device on a belt which is mechanically coupled to one of the gripping elements to move the gripping element by the belt movement relative to the other gripping element of the gripping device and to a arranged between the two gripping elements Blattgutstapel by a Greifklemmung fen. The gripping element is mechanically designed so that the drive of the belt movement also provides the force for tilting the tiltable gripper finger. The tilting is triggered by the opposing force of the compressed sheet stack. For tilting the gripper finger therefore advantageously no further drive or actuator is needed. The relative movement of the gripping elements can also be achieved without the aid of belts.

In this embodiment, for example, the belt tension can be monitored by a sensor for the stopping mechanism, which can be used for this purpose. is directed to stop the drive of the belt movement when exceeding a certain belt tension. The sensor for mechanical monitoring of the belt tension is preferably arranged in that section along the belt in which, in the case of gripping clamping of the stack of sheets, during further movement of the gripping element, an increased belt tension is produced by the counterforce of the stack of sheets. In particular, the sensor has a roller which is pressed against the belt (eg by spring force) for monitoring the belt tension and which, in the case of gripping clamping of the sheet material stack, is deflected by the belt tension being increased during the further movement of the gripping element. The deflection of the roller is monitored, for example, by a proximity sensor which monitors the position of the roller. If a certain deflection of the roller is exceeded, the sensor shuts off the motor of the belt movement.

The gripping device is set up in particular for removing a sheet material stack from a container which has side walls with a meander-shaped surface. The sidewall having the meandering surface may be formed by a separator received in the container or by the inner wall of the container itself. For this purpose, the gripping device preferably has two gripper elements each comprising at least two gripper fingers, which are designed to immerse in recesses of the meander-shaped surface of a side wall of the container in which the sheet material stack is contained. If the container is arranged with its open side up and the sheet material in the container is on its edges, the gripping device can grab the sheet stack and lift out of the container against gravity. The side wall of the container, which has the meandering surface, in some containers on a projection-free portion, ie a portion in which no projection of the meandering side wall is present. The stack end sheet of a sheet material stack contained in the container facing this side wall can bulge out in this projection-free section towards the side wall. In such a case, therefore, at least one of the gripping fingers, which is provided for gripping the sheet material stack for immersion in this projection-free section of the side wall, is beveled at its outer end in such a way that it projects between the stack end sheet bulged towards the side wall and the projection-free section can dive. The outer end of this gripper finger, which lies on the side facing away from the attachment of the gripper finger side of the gripper finger, is chamfered such that the thickness of the gripper finger decreases along the direction towards the middle of the projection-free portion direction. Thus, a bulged Stapelendblatt can be safely gripped by the gripping device and the complete stack can be removed without damage from the container.

The invention also includes a device for processing sheet material, in particular value documents, which has a gripping device according to the invention. The device can be a value-document processing device that has an input pocket for the value documents, a transport system for transporting the value documents, sensors for checking the value documents, and one or more output pockets for the value documents. However, the device can also essentially provide only the gripping device and be designed to be attached to such a value-document processing device, or be provided for use with such a value-document processing device. The gripping device of the device can be set up for this purpose be inserted in the input tray of the value document processing device the gripped document of value stack and / or remove the gripped sheet stack from an output tray of the value document processing device.

The invention also relates to a method for gripping a sheet material stack by means of the gripping device. In this case, a relative movement of the gripping elements toward each other by a relative movement of the gripping elements to compress a arranged between the two gripping elements arranged sheet stack and grab by Greifklemmung. At least one of the gripping fingers is thereby tilted from its initial position to its tilted position. The tilting of the gripper finger can be carried out before the start of the relative movement or during the relative movement. The relative movement of the gripping elements is automatically stopped as soon as a gripping clamping is achieved, in particular as soon as a counterforce of the sheet material stack generated during gripping clamping exceeds a predetermined value. Then, the sheet material stack gripped by the gripping clamping is transported by means of the gripping device. After the relative movement has stopped, the relative movement of the gripper elements is preferably halted for a certain waiting time and after this waiting time the sheet material stack is retrieved, in which the relative movement of the gripping elements towards each other is restarted, in order to ensure a secure movement even in the case of a relaxation of the sheet material stack Greifklemmung the sheet stack produce. The restarted relative movement of the gripping elements is in turn automatically stopped, in particular as soon as the counterforce of the sheet material stack generated during the renewed gripping clamping again exceeds the predetermined value. In particular, the method for removing a sheet material stack from a container by means of the gripping device is advantageous. The tilting of the gripping fingers then takes place, for example, after the gripping fingers have been immersed in the recesses of a meandering sidewall. The step of transporting the sheet material stack gripped by the gripping clamp by means of the gripping device in this case comprises that the gripping clamp removes the gripped sheet material stack from the container.

The Greifeinrichrung performs the catching while it transports the Blattgut- stack, especially after the gripping device has removed the sheet stack from the container. By Nachgreifen the desired gripping force is set again, for example, about the same value as in the first Greifklemmung. By catching a secure gripping even such stack of sheets is achieved, relax. The relaxation of the sheet material stack can be achieved by inelastic deformation _. the sheet stack by the compression when gripping come about, for example, small positional shifts between the leaves of the sheet material. The waiting time is chosen so that the sheet material stack has sufficient time after reaching the Greifklemmung to relax under the influence of gripping force, gravity and possibly its inertial force. For example, the waiting time between the automatic stopping of the relative movement and the Nachgreifen is a few tenths of seconds.

The invention will be described below with reference to banknotes as an example of the value documents. However, the invention is not limited thereto, but sheet material in general suitable, in particular for any types of value documents. The invention enables, for example, the automatic processing of large quantities of banknotes, wherein the banknotes are prepared in advance for processing and filled into the containers. The Removing the banknotes from the container and inserting the banknotes removed from the container into the input compartment of a banknote processing device with the aid of the gripping device as well as the processing of the banknotes in the device can then take place completely automatically, without manual manipulations by an operator.

The invention will be explained by way of example with reference to the following figures. 1a-b show a container partially filled with banknotes together with a gripper known per se (FIG. 1a) and a container together with gripping elements of a gripping device according to the invention (FIG. 1b), FIGS Times when one of the gripping elements is moved towards the other,

3a-b gripping device when grasping a lefty banknote stack (FIG. 3a) or when grasping a right-handed banknote stack (FIG. 3b), FIG.

Fig. 4a-b gripping element with conventional gripping fingers, and

Fig. 5a-b specially designed gripping element for secure gripping the

Paper money.

FIG. 1 a shows a container 100 partially filled with banknotes together with a gripper 9 known per se. The container 100 is formed by a housing which is closed on five sides and has a number of pockets. having dividers, which separators 101 can receive interchangeable. Banknote stacks 1 can be entered between the meander-shaped separating elements 101. The banknotes are entered in such a way that they stand on their longitudinal edges in the container 100. This allows a safe and ergonomically favorable filling of the container. To automatically remove banknotes from the container 100, the gripper 9 is lowered into the container 1, with its gripping elements immersed in the recesses of the separating elements 101. After lowering, the two gripping elements of the gripper 9 are moved towards each other to grab a stack of notes 1 and lift out of the container.

Also shown in FIG. 1b is a container 100 for receiving bank notes standing on its longitudinal edges (the banknote stack 1 is not shown in FIG. 1b). To remove the banknotes, a gripping device 10 according to the invention with two gripping dements 21, 41 is used, which can be moved toward and away from each other. The gripping elements 21, 41 are part of the gripping device 10, which is described in detail with reference to the figures 2a-d, and of which only the two gripping elements 21, 41 are shown in Figure lb. At least one of the gripping elements extends substantially over the entire inside width of the container 100 in order to securely grasp and later deposit banknote stacks 1. In addition, the gripping device 10 can have sensors for the positioning of the gripping elements 21, 41 Signals are evaluated by a control device to control the movement of the gripping device 10.

For example, for each container, all banknotes are aligned with their side edges on the same side wall of the respective container 100. This ensures that the gripping elements 21, 41 the respective banknote Stack 1 - without adjustment of the lateral position of the gripping elements 21, 41 - always at the same gripping points (in relation to the banknote stack) can grip. The lateral position of the gripping element 21 in FIG. 1b is, for example, to the right of the center of the container and arranged such that the two gripping points are arranged on both sides and symmetrically to the center of the smallest possible banknote format, provided that the banknotes are aligned on the right-hand side wall of the container 100. If the banknotes are always aligned on the right side wall, these gripping points are in the same position with respect to the smallest possible banknote format for each banknote stack.

The separating elements 101 are provided on both sides with a meander-shaped surface so that the gripping elements 21, 41 can dive defined between banknotes located in the container 100 in order to grip a stack of banknotes and remove them from the container 100. The arrangement and extent of the gripping fingers of the gripping elements 21, 41 are adapted to the meandering shape of the separating elements 101, so that they can dive into the recesses of the meandering surface. Similar to the separating elements, the front and rear inner walls of the container also have a meander-shaped surface with projections and recesses, which likewise makes it possible to immerse the gripping fingers of the gripping elements.

The banknote stack 1 removed from the container 100 by the gripping device 10 is then fed to a processing, for example by means of a banknote processing device. For this purpose, the gripping device 10 inserts the banknote stack into an input compartment of the banknote processing device, from which the banknotes are individually transported away by means of a singler. The gripping device 10 becomes this

Purpose in the area of the input tray of the bank note processing device arranged to the removed from the container 100 banknotes in a Insert input tray. Within reach of the gripping device 10, a suitable receiving device for one or more containers 100 may be provided. Subsequently, the banknotes are processed in the banknote processing device, stored in bins of the banknote processing device and billed.

Figure 2a shows a gripping device 10 according to the invention with the two gripping elements 21 and 41. For gripping a banknote stack 1, the movable gripping member 21 is moved to the fixed gripping member 41. The gripping element 21 of the gripping device 10 has a carriage 24 which is mechanically coupled to a belt 32 of the gripping device 10. By the movement of the belt 32, the gripping member 21 can be linearly moved toward and away from the gripping member 41. The belt 32 is moved by a motor 30 which drives the drive roller 31 of the belt. The fixed gripping member 41 has a plurality of gripping fingers 42 which are distributed over the entire length of the banknote stack. The fixed gripping element may alternatively have less gripping fingers. The movable gripping element 21 has only two gripping fingers 22 in this example. Alternatively, instead of the two gripper fingers 22, a single broad gripping finger or more than two gripper fingers can be used for the movable gripping element. Also, the movable gripping member 21 may have a plurality of gripper fingers 22 which are distributed over the entire length of the banknote stack. In Figure 2a-d, the gripping device 10 is shown at different times when the gripping member 21 is continuously or stepwise moved to the other gripping member 41 to grip the banknote stack 1. In Figure 2a, the gripping member 21 is moved to the Stapelendblatt 2 of the banknote stack 1, but this does not affect. In Figure 2b is the Time of contact between the gripping element 21 and Stapelendblatt 2 shown. Figure 2c shows a time at which the banknote stack 1 is already pressed by the gripping member 21 against the gripping member 41, the gripping finger 22 but are still in their non-tilted initial position A. FIG. 2 d shows the gripping device after the gripping fingers 22 have been tilted into their tilted position K and the banknote stack 1 has been gripped.

The gripping fingers 22 of the gripping element 21 are tiltable towards the banknote stack 1 by a mechanical tilting mechanism which the gripper element 21 has. The function of the tilting mechanism will be apparent from a comparison of Figures 2c and 2d. Starting from FIG. 2 c, in which the gripping fingers 22 are in their un-tilted starting position A, the carriage 24 of the gripping element 21 is moved further to the left by means of the belt 32. As the gripping element 21 advances, a counter force is exerted on the gripping fingers 22 by the banknote stack 1, which prevents the gripping fingers 22 and the associated lower part 23 of the gripping element 21 from following the left movement of the carriage 24. The further movement of the carriage 24 to the left and the counterforce of the banknote stack 1 on the gripping fingers 22 and on the lower part 23 leads to a torque on the side part 25 of the gripping element 21, which is mounted on the carriage 24 and the lower part 23 accordingly. The side member 25 is thereby rotated counterclockwise by an angle. By the rotation of the side member 25, the lower part 23 of the gripping member, which is mounted on its left side, is rotated clockwise. The gripping fingers 22, which are attached to the lower part 23, are tilted by the rotation of the lower part 23 in its tilted position K, for example by a tilt angle α of a few degrees about the axis 28, see. Figure 2d. The rotation of the lower part 23 counteracts the force of the spring 26, which is tensioned by the rotation of the lower part 23. To release the banknote stack 1, the Gripping elements 21, 1 moved apart again. Once the counterforce of the banknote stack 1 is removed, the gripping element 21 returns by the force of the spring 26 back to its original state, the gripping fingers 22 return to their original untilted position A.

In addition or as an alternative to the purely mechanically controlled tilting mechanism just described, it is also possible to electronically trigger and control the tilting mechanism of the gripping fingers, e.g. with the help of appropriate actuators for tilting the gripper fingers and sensors. For this purpose, sensors can be used which determine the position of the movable

Detect gripping elements and / or detect the collapse of the stack, the counterforce of the banknote stack to trigger the tilting of the gripping fingers and to stop the relative movement of the gripping elements. If the banknote stack to be gripped is located in a container, such as the container 100 of FIG. 1b, the movable gripping element 21 is moved towards the stationary gripper element 41 in a raised position of the gripping element 41 (FIGS. 2a, 2b). So before the gripping elements are lowered into the container 100. Only after the position of the two gripping elements 21, 41 is correct to immerse in the recesses of the respective meander-shaped surface, the gripping device 10 is lowered into the container 100. This lowering takes place between the times of FIGS. 2b and 2c. After the gripping fingers are immersed in the recesses of the separating elements 101 and the inner wall of the container 100, the movable gripping member 21 is further moved to the gripping member 41 to compress the stack of notes 1 (Fig. 2c) and the gripping fingers 22 to tilt ( Fig. 2d). The banknote stack 1 is gripped and can then be safely lifted out of the container 100. The gripping device 10 has, for example, a mechanically controlled stopping mechanism for automatically stopping the movement of the gripping element 21 as soon as a counterforce of the sheet material stack 1 generated during gripping clamping exceeds a certain value. In the mechanically controlled stopping mechanism, the belt tension of the belt 32 is monitored by a sensor. The sensor for monitoring the belt tension is arranged in that section along the belt 32, in which, in the case of gripping clamping of the sheet material stack, as the gripping element 21 moves further, an increased belt tension is produced by the counterforce of the sheet material stack 1. In FIGS. 2a-d, this is the portion of the belt 32 that lies along the direction of movement of the belt between the carriage 24 of the gripping device 21 and the drive roller 31.

The sensor has a roller 34, which is pressed against the belt by a spring for monitoring the belt tension. In the case of Greifklemmung the sheet stack 1, the belt tension increases in the area of the roller 34 by acting on advancing the gripping member 21 counterforce of the sheet stack 1 and by the driving force of the drive roller 31. Due to the increased belt tension, the roller 34 by the belt 32 against the Spring force deflected (compared to Figure 2c, the roller 34 is deflected in Figure 2d slightly upwards). The deflection of the roller 34 is monitored, for example by a proximity sensor 33, which monitors the position of the role, for example, inductive or capacitive. If a certain deflection of the roller 34 is exceeded, the proximity sensor 33 switches off the motor 30 used for driving the belt, so that the movement of the gripping element 21 is automatically stopped. The motor 30 is preferably a motor with self-locking gear, so that the Greifklemmung the banknote stack 1 is maintained even when the engine 30. When the gripper elements 21, 41 move apart, the roller le 34, as soon as the belt tension is normal again, pressed by the deflection counteracting spring force to the belt 32 again.

In the case of banknote stacks, foil elements of the banknotes, eg security elements which are applied to the banknotes, can lead to an uneven stack height and / or to uneven mechanical properties of the banknote stack 1. Because the film elements can lead to a local bulge of banknotes in a particular area or increase the local thickness of the banknotes. In the case of the plurality of banknotes in a banknote stack, banknote stacks with an oblique or wavy surface or, depending on the position along the stacking surface, have a different elasticity and therefore provide a locally different opposing force, cf. FIGS. 3a-b. In order to securely grasp also such banknote stack, in a preferred embodiment, at least one of the gripping elements (the same, which also has tiltable gripping finger and / or the other gripping element) to a compensating movement, which allows an adaptation of the gripping element to uneven Blattgutstapel. This will be explained below using the example of the gripping element 21. For gripping the banknote stack, the two gripping fingers 22 of the gripping element 21 are arranged on both sides of the center M of the banknote stack 1, cf. Fig. 2c. The gripping fingers 22 are fastened to the lower part 23 of the gripping element 21 in such a way that they can be moved into different positions relative to the lower part 23 along the direction perpendicular to the stacking surface of the sheet material stack 1. This compensating movement of the gripping fingers is independent of the tilting movement shown in FIGS. 2c-d for tilting the gripping fingers. In the example of Figures 3a-b, the gripping fingers 22 are formed by a fork. This fork is rotatably mounted on an axis 27 which is oriented approximately parallel to the gripper fingers 22 and which lies approximately on the mid-perpendicular between the two gripping fingers, cf. FIGS. 3a-b. The two gripping fingers 22 are therefore deflectable in different positions perpendicular to the stack surface. When grasping a stack having a nonuniform height or uneven mechanical properties, the gripper fingers therefore move in opposite directions. The rotation of the gripping fingers 22 about the axis 27 counteracts the spring force of the spring 26. In FIG. 3 a, the gripping device 10 grips a sheet material stack 1 whose left side has greater elasticity than its right side, so that the gripping fingers 22 are automatically rotated about the axis 27 counterclockwise when the stack is compressed. In FIG. 3 b, the gripping device 10 grips another sheet material stack 1 whose right-hand side has greater elasticity than its left-hand side, so that the gripping fingers 22 are rotated somewhat clockwise about the axis 27.

In Figures 4a-b, the gripping element 41 is shown when immersed in the recesses of the meandering surface of a separator 100 contained in a banknote container 100. In order to facilitate manual removal and manual insertion of the banknote stack into the container 100, the separating element 101 has a projection-free section 102 on which the meandering shape is interrupted and which has a recessed grip. A banknote BN, for example the stack end sheet 2 of a banknote stack 1 received in the container, can bulge out into this projection-free section 102, cf. FIG. 4a. When lowering the gripping member 41, therefore, there is a risk that the two in this projection-free portion 102 meeting gripping fingers 42 not in the gap between sink the banknote BN and the separating element 101, but hit the front side of the banknote BN and damage it, cf. FIG. 4b.

FIGS. 5a-b show an embodiment of the gripper fingers improved in this respect. The two gripping fingers 42, which are provided for gripping the sheet material stack for immersion in the projection-free portion 102, are chamfered at their outer ends. The chamfer is such that the thickness of the gripper finger, which it has perpendicular to the direction of the gripper finger, decreases along the direction of the center of the projection-free portion 102 direction. Thus, these gripping fingers can easily dip between the outwardly arched banknote BN and the projection-free section 102, cf. FIG. 5b. Thus, even in the case of the bulging of a banknote into a projection-free section, this banknote or the stack is securely gripped without damaging banknotes.

Claims

Patent claims

1. gripping device for gripping and transporting a stack of sheets having at least two gripping elements (21, 41) for gripping a sheet material stack (1) arranged between the gripping elements, which are movable towards each other to grip the stack of sheets (1) by a Greifklemmung wherein the gripping elements (21, 41) each have at least one gripping finger (22, 42) which can be applied to a stack end sheet, which is located at the end of the sheet material stack facing the respective gripping element (21, 41), in that the gripping finger (22, 42) contacts the respective stacking end sheet in a planar manner, characterized in that at least one of the gripping fingers (22) has at least one of the gripping elements (21) from a starting position (A) in which the gripping finger (22 ) is oriented substantially parallel to the surface of the stack end sheet (2) facing it, can be tilted into a tilted position (K), in which the gripping finger (22) is tilted towards the surface of it facing Stapelendblatts (2) is inclined towards.

2. gripping device according to claim 1, characterized in that the tiltable gripping finger (22) is tilted such that the outer end of the tiltable gripping finger, which faces away from the attachment of the tiltable gripper finger on the gripping element (21), by tilting to Surface of the tiltable gripping finger (22) facing the stack end plate (2) is inclined towards.

3. Gripping device according to one of the preceding claims, characterized in that the tiltable gripping finger about an axis (28) is tiltable, which is oriented approximately parallel to the surface of the gripping finger facing Stapelendblatts (2) and having a non-zero angle with the Direction of the gripper finger (22) includes.

4. Gripping device according to one of the preceding claims, characterized in that tilting of the gripper finger (22) displaces the point of application of the gripping force of the tiltable gripper finger to a gripping point, which lies in the middle region of the sheet material stack (1).

5. Gripping device according to one of the preceding claims, characterized in that, when the one or more tiltable gripping fingers (22) in the tilted position (K), the gripping elements (21, 41) exert a Greifklemmung on the sheet material stack (1), the sufficient to hold the sheet stack by the Greifklemmung against its gravity.

6. gripping device according to one of the preceding claims, characterized in that the gripping element (21) having the tiltable gripping fingers (22), with a belt (32) is mechanically coupled to the

To move the gripping element (21) by the belt movement relative to the other gripping element (41) of the gripping device and to grip the sheet material stack (1) arranged between the two gripping elements (21, 41) by a gripping clamp, wherein the gripping element (21) mechanically is designed that the drive of the belt movement also provides the force for tilting the tiltable gripper finger.

7. gripping device according to one of the preceding claims, characterized in that at least the gripping fingers (22, 42) of one of the gripping elements (21, 41) are formed for a compensating movement, which allows an adjustment of the position of the gripper fingers (22) to uneven Blattgutstapel, wherein the gripping fingers (22, 42) are fastened to the gripping element (21, 41) in particular in such a way that they move along the gripping element, relative to the gripping element the direction perpendicular to the stack surface of the sheet material stack (1), are movable in different positions.

8. gripping device according to claim 7, characterized in that the gripping element comprises two gripping fingers (22) which are formed by a fork, which is rotatable for the compensating movement about an axis (27) which is oriented approximately parallel to the gripper fingers (22) is and preferably approximately on the mid-perpendicular between the two gripping fingers (22).

9. gripping device according to one of the preceding claims, characterized in that the gripping device comprises a stop mechanism for stopping the relative movement of the gripping elements (21, 41), wherein the drive (30) of the relative movement is automatically switched off as soon as a generated in the Greifklemmung Counterforce of the sheet material stack (1) exceeds a certain value.

10. gripping device according to claim 9, characterized in that the gripping device comprises a belt (32) which is mechanically coupled to one of the gripping elements (21) to this gripping element by the belt movement relative to the other gripping element (41) of the gripping device to move and to grip the arranged between the two gripping elements sheet stack (1) by a Greifklemmung, wherein the stop mechanism comprises that the belt tension is monitored by a sensor (33) which is adapted to at Exceeding a certain belt tension stops the drive of the belt movement.

11. Gripping device according to one of the preceding claims, characterized in that the gripping device is adapted to remove a stack of sheets from a container having at least one side wall having a meandering surface, and in that the gripping device comprises two gripping elements (21, 41) each having at least two gripping fingers (22, 2) which are adapted to immerse in recesses of the meandering surface of the side wall of the container.

12. gripping device according to claim 11, characterized in that the side wall of the container, which has the meandering surface, a projection-free portion (102), so that the Stapelendblatt a sheet material stack contained in the container in this jump-free section (102) can bulge out at the side wall, and that at least one of the gripping fingers, which is provided when gripping the stack of sheets for immersion in this projection-free portion of the side wall, is chamfered at its outer end so that it between the bulging towards the side wall Stapelendblatt (2) and can dip into the non-protruding section (102).

13. An apparatus for processing sheet material, in particular value documents, which has a gripping device (10) according to one of claims 1 to 12, wherein the gripping device (10) is adapted to the gripped NEN sheet stack (1) in an input tray of the device to insert and / or wherein the gripping device is adapted to remove the gripped sheet stack from an output tray of the device.

14. A method for gripping a stack of sheets by means of a gripping device (10) according to one of the preceding claims, for example to remove a sheet stack from a container (100), comprising the steps of: - relative movement of the gripping elements (21, 41) towards each other by a relative movement of the gripping elements in order to compress a sheet arranged between the two gripping elements stack (1) and grab by Greifklemmung, wherein at least one of the gripping fingers of the gripping elements (21, 41) is tilted from its initial position (A) in its tilted position (K), and

- Automatically stopping the relative movement of the gripping elements (21, 41), as soon as a Greifklemmung is reached, especially when a at the

Greifklemmung generated counterforce of the sheet stack (1) exceeds a certain value, and

- Transporting the grasped by the Greifklemmung sheet stack (1) by means of the gripping device (10), wherein the Greifklemmung the grasped sheet stack (1), for example, from the container (100).

15. The method according to claim 14, characterized in that the relative movement of the gripping elements (21, 41) after stopping the relative movement a certain waiting time is stopped, and that after the waiting time a Nachgreifen the sheet material stack (1) is performed, wherein the relative movement the gripping elements (21, 41) is started again to each other to produce a secure gripping clamping of the sheet material stack even in the case of a relaxation of the sheet material stack (1).