EP2841368B1 - Gripping device for gripping sheets - Google Patents

Description

The present invention relates to a gripping device and a method for gripping sheet material, in particular a stack of sheets, as well as 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 stack of sheets from a container and deposit the removed stack of sheets at a desired destination position again.

For the processing of value documents, for example, containers are used which can be opened on one side 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. FIG. 1a , 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 automatically from the container by means of a gripper, a gripper with several gripper fingers can be inserted, which dive into the recesses of the meander-shaped surface from above. 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 against acceleration forces, it must depend on the friction between the gripper and the sheet located on the stack surface and on the friction between the sheets of the stack, and these frictional forces will vary depending on the nature and condition of the sheets. So far, therefore, a secure and trouble-free removal of sheet stacks is therefore possible only for certain types of sheet stacks.

Out US 5,425,565 It is known to form the gripper such that the gripping fingers can be inclined in the direction of a sheet material stack formed from a predetermined amount of sheets. As a result, the sheet stack is stretched arcuately, whereby its removal is supported. Similar grippers are also off WO 2006/086160 A1 and FR 2740439 A1 known.

The object of the present invention is to provide an improved solution for removing a sheet stack located in a container by means of a gripper from the container and hold by gripping clamping 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 by means of a drive, in order to grasp the sheet material stack and to move away from one another in order to release the sheet material stack. For this purpose, one of the gripping elements may be designed to be movable and the other fixed or both may be designed to be movable. In order to achieve gripping clamping of the sheet stack at both ends of the stack, the gripper engages the stack by compressing the stack at both ends of the stack toward the stack. The gripping device preferably has a stop mechanism for shutting off the drive, which drives the relative movement of the gripping elements, and thus for automatically stopping the relative movement of the gripping elements as soon as a counterforce of the sheet material stack generated in the Greifklemmung 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. 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. At least one of the gripping fingers of one of the gripper elements is tilted from its initial position, in which it is oriented substantially 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 tilting of the gripper finger displaces the point at which the gripping force of the gripper finger acts on the stack of sheets largely on a gripping point, which is no longer at the edge, but in particular in the middle region of the sheet material stack. The tilting of the gripper finger counteracts a decreasing gripping clamping, which results from the elastic bending of the gripping finger. This allows a secure gripping and transporting very large stacks of sheets and mixed stacks of different sized sheets. However, the gripping device 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 to each other so 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 that 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 they exercise in their tilted position a Greifklemmung on the stack, which is sufficient to hold the stack of sheet against its gravity, and in particular 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 adapted for transporting a stack of sheets from a home position to a target position. The gripping device may for this purpose be e.g. be attached to the articulated arm of a Gelenkarmroboters to allow three-dimensional movements of the gripping device in space (translational and rotational movements). For example, the gripping device 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 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-fed stack end sheet and which encloses 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 in such a way that, in its tilted position, it is inclined along the direction perpendicular to the surface of the stack end sheet facing it (also referred to below as "stack surface"). The outer end of the tiltable gripper finger, which faces away from the attachment of the tiltable gripper finger on the gripping element, is tilted towards the stack surface. In the tilted position, the outer end of the tiltable gripping finger is displaced perpendicular to the stacking surface relative to those portions of the tiltable gripping finger that are closer to the attachment of the tiltable gripping finger to the gripping member than the outer end. 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 gripper member have the same position along the direction perpendicular to the stack surface. In its initial position, the gripper finger can be placed on the stack end sheet in particular such that the gripper finger flatly contacts the stack end sheet over at least a quarter of the length of the stack end sheet, preferably at least over half the length, with the length of the stack end sheet being viewed 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 sheet stack, the attachment of the tiltable gripper finger on the Facing away gripping element. In the tilted position, the outer end of the tiltable gripping finger exerts the gripping force on the sheet material stack at a gripping point on the stack end sheet, 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 stack of sheet material the sheet stack has in the direction of the gripper finger. Preferably, the gripping point lies along this direction approximately in the middle of the sheet material stack. The gripping point at which the gripper finger in its tilted position essentially holds the sheet material stack is, for example, a point of contact, wherein due to the elasticity of the sheet material stack, but also in the tilted position, a flat 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 gripping fingers, which are arranged on both sides of the center of the sheet material stack, in particular which are arranged approximately symmetrically to the middle of the sheet material stack. In each case, the outer end of the tiltable gripper 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 middle of the sheet material stack, they are preferably symmetrical to the center 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 gripper fingers are preferably selected symmetrically to the center of the smallest sheet of the sheet stack. According to the invention, at least the gripping fingers of one of the gripper elements are designed to carry out a compensation movement, which allows an adaptation of the position of the gripper fingers to uneven stacked sheets. This may be the same gripping element, which also has the / the tiltable gripping fingers and / or the other gripping element that does not tilt Greiffinger has. For the compensating movement, the gripping fingers are attached to the gripping element in such a way that, relative to the gripping element, they can be moved into mutually different positions along the direction perpendicular to the stacking surface of the sheet material stack. The gripping fingers designed for compensating movement are fastened to the gripping element in such a way that they can be deflected relative to the gripping element along the direction perpendicular to the stacking surface against a spring force. 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 compensating movement of the gripper fingers is independent of the above tilting movement for tilting the gripper fingers.

The mobility of the gripping fingers in different positions perpendicular to the banknote stack causes the position of the respective gripper finger, which, at the time of Greifklemmung the stack occupies relative to the gripping element, depending on the local stack height and / or in dependence of 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. With a very different force distribution, there is a risk that the stack will slip out under the influence of gravity from the Greifklemmung the other gripper finger and the stack by the resulting torque to the gripping point of the former Greiffingers is twisted. 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 gripping fingers exert approximately 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 to enable the compensating movement, which is oriented approximately parallel to the gripper fingers and in particular lies approximately on the mid-perpendicular between the two gripping fingers. 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.

In one embodiment, the gripping device comprises 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 grasp a stack of sheets arranged between the two gripping elements by a gripping clamp. The gripping element is mechanically designed such 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 The gripping elements can also be achieved without the aid of belts.

In this embodiment, for the stopping mechanism, e.g. the belt tension is monitored by a sensor designed to stop belt drive 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 for monitoring the belt tension (for example by spring force) and which, in the case of gripping clamping of the stack of sheets, is deflected by the belt tension being increased during the further movement of the gripping element. The deflection of the roll is e.g. monitored by a proximity sensor that 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 so that its has open side up and the sheet material in the container is on its edges, the gripper 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 has a projection-free portion, i. a section in which no projection of the meandering side wall is present. The stack end sheet facing this side wall of a sheet material stack contained in the container can bulge out in this projection-free section towards the side wall. Preferably, in such a case, therefore, at least one of the gripping fingers, which is provided when gripping the sheet material stack for immersion in this projection-free portion of the side wall, beveled at its outer end so that it can dive between the stacked towards the side wall Stapelendblatt and the projection-free section , The outer end of this gripper finger, which is located on the side remote 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 of the projection-free portion facing 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 may be a value-document processing device which 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. The device can also essentially only the Be ready gripping device and be adapted 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 to load the gripped value-document stack into the input tray of the value-document processing device and / or to remove the gripped sheet-material 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 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. The relative movement of the gripping elements is preferably stopped after stopping the relative movement a certain waiting time and after this waiting time a Nachgreifen the sheet material stack is performed, in which the relative movement of the gripping elements is started to each other again, even in the case of relaxation of the sheet stack a secure Greifklemmung of Produce sheet stack. The restarted relative movement of the gripping elements is in turn automatically stopped, in particular as soon as the opposing force of the sheet material stack generated during the renewed Greifklemmung 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 gripper fingers then takes place e.g. after the gripping fingers were immersed in the recesses of a meandering side wall. 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 gripping device performs the catching while it transports the stack of sheets, in particular after the gripping device has removed the sheet stack from the container. By picking up the desired gripping force is adjusted again, e.g. about the same value as the first Greifklemmung. By catching a secure gripping even such stack of sheets is achieved, relax. The relaxation of the sheet stacks can be accomplished by inelastic deformation of the stack of sheets by squeezing when gripping, e.g. slight 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 removal of the banknotes from the container and the insertion of the banknotes taken out of the container into the input compartment of a banknote processing device by means of the gripping device as well as the processing of the banknotes in the device can then take place completely automatically, without manual manipulations of an operator.

Fig. 1a-b

einen teilweise mit Banknoten gefüllten Behälter zusammen mit einem an sich bekannten Greifer (Fig. 1a) und einen Behälter zusammen mit Greifelementen einer Ausführungsform einer Greifeinrichtung (Fig. 1b),

Fig. 2a-d

Greifeinrichtung zu verschiedenen Zeitpunkten, wenn eines der Greifelemente auf das andere zu bewegt wird,

Fig. 3a-b

Greifeinrichtung beim Greifen eines linksnachgiebigen Banknotenstapels (Fig. 3a) bzw. beim Greifen eines rechtsnachgiebigen Banknotenstapels (Fig. 3b),

Fig. 4a-b

Greifelement mit konventionellen Greiffingern, und

Fig. 5a-b

speziell ausgebildetes Greifelement zum sicheren Greifen der Banknoten.

The invention will be explained by way of example with reference to the following figures. Show it:

Fig. 1a-b

a partially filled with banknotes container together with a known gripper ( Fig. 1a ) and a container together with gripping elements of an embodiment of a gripping device ( Fig. 1b )

Fig. 2a-d

Gripping device at different times when one of the gripping elements is moved towards the other,

Fig. 3a-b

Gripping device when gripping a lefty banknote stack ( Fig. 3a ) or when gripping a legally compliant banknote stack ( Fig. 3b )

Fig. 4a-b

Gripping element with conventional gripper fingers, and

Fig. 5a-b

specially designed gripping element for secure gripping the banknotes.

FIG. 1a shows a partially filled with banknotes container 100 together with a per se known gripper 9. The container 100 is formed by a on a five-sided closed housing having a plurality of divisions, which can accommodate separators 101 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 in FIG. 1b a container 100 for receiving bank notes standing on its longitudinal edges is shown (the banknote stack 1 is shown in FIG FIG. 1b Not shown). For removing the banknotes, a gripping device 10 with two gripping elements 21, 41 is used, which can be moved towards and away from each other. The gripping elements 21, 41 are part of the gripping device 10, which are based on the FIGS. 2a-d is described in detail, and of the in FIG. 1b only the two gripping elements 21, 41 are shown. At least one of the gripping elements extends substantially over the entire inside width of the container 100 in order to be able to securely grasp and later deposit banknote stacks 1. In addition, the gripping device 10 can have sensors for positioning the gripping elements 21, 41 whose signals are from a control device are evaluated 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 adaptation of the lateral position of the gripping elements 21, 41 - always at the same gripping points (in relation to the banknote stack) can grab. The lateral position of the gripping element 21 in FIG. 1b is eg right of the center of the container and chosen so 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 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 places the banknote stack in an input compartment of the banknote processing device one from which the banknotes are individually transported away by means of a singler. For this purpose, the gripping device 10 is arranged in the region of the input compartment of the banknote processing device in order to be able to place the banknotes removed from the container 100 into an input compartment. 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.

FIG. 2a shows a gripping device 10 with the two gripping elements 21 and 41. For gripping a stack of banknotes 1, the movable gripping element 21 is moved toward the stationary gripping element 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 element 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 gripping fingers 22, a single, wide gripping finger or more than two gripping 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 For example, the gripper 10 is shown at different times when the gripping member 21 is moved toward the other gripping member 41 continuously or stepwise to grip the stack of notes 1. In FIG. 2a the gripping element 21 is moved towards the Stapelendblatt 2 of the banknote stack 1, but this does not affect. In FIG. 2b the time of contact between the gripping element 21 and stack end sheet 2 is 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, but the gripping fingers 22 are still in their un-tilted initial position A. Figure 2d shows the gripping device after the gripping fingers 22 have been tilted into its tilted position K and the banknote stack 1 is 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 tilt mechanism is based on a comparison of Figures 2c and 2d clear. Starting from Figure 2c , in which the gripping fingers 22 are in their untilted 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 member 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 Gripper fingers 22, which are fastened to the lower part 23, are tilted by the rotation of the lower part 23 into its tilted position K, for example by a tilt angle α of a few degrees about the axis 28, cf. 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, 41 are moved apart again. As soon as the counterforce of the banknote stack 1 is removed, the gripping element 21 returns to its original state by the force of the spring 26, with the gripping fingers 22 returning to their initial, unskapped 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, it is possible to use sensors which detect the position of the movable gripping element and / or which detect the counterforce of the banknote stack when the stack is compressed in order 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 in a container, such as the container 100 from FIG. 1b is located, the movable gripping member 21 is moved in a raised position of the gripping device 10 to the fixed gripping member 41 ( Fig. 2a, Fig. 2b ), ie 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 reduction takes place between the times of FIGS. 2b and 2c instead of. After the gripper fingers in the recesses the partition 101 or the inner wall of the container 100 are immersed, the movable gripping member 21 is further moved to the gripping member 41 to compress the stack of notes 1 ( Fig. 2c ) and the gripper 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 the portion along the belt 32, in which an increased belt tension is generated in the case of Greifklemmung the sheet stack, further advancing the gripping member 21 by the opposing force of the sheet material stack 1. In the 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 is the role 34 in Figure 2d deflected 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 the roller 34 is exceeded, the proximity sensor 33 turns off the motor 30 used for driving the belt, so that the movement of the gripping member 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 moving apart of the gripping elements 21, 41, the roller 34, as soon as the belt tension is normal again, pressed by the deflection of the counteracting spring force against the belt 32 again. In the case of banknote stacks, foil elements of the banknotes, for example 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 stacks, according to the invention at least one of the gripping elements (the same which also has tiltable gripping fingers and / or the other gripping element) is designed to carry out a compensation movement which allows an adaptation of the gripping element to uneven stacked sheets. 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 so on the lower part 23 of the gripping member 21 attached, that they, relative to the lower part 23, along the direction perpendicular to the stacking surface of the sheet material stack 1, are movable into different positions. This compensating movement of the gripper fingers is independent of the in the Figures 2c-d shown tilting movement for tilting the gripper fingers.

In the example of FIGS. 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. 3a the gripping device 10 grips a stack of sheets 1 whose left side has a greater elasticity than its right side, so that the gripping fingers 22 are automatically rotated about the axis 27 in a counterclockwise direction when the stack is compressed. In FIG. 3b grips the gripping device 10 another sheet stack 1, the right side has a greater elasticity than the left side, so that the gripping fingers 22 are rotated slightly clockwise about the axis 27.

In the FIGS. 4a-b the gripping element 41 is shown immersed in the recesses of the meandering surface of a separating element 101 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 having. 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 element 41, therefore, there is a risk that the two gripping fingers 42 which come into this projection-free section 102 do not dive into the gap between the banknote BN and the separating element 101, but hit the end face of the banknote BN and damage it, cf. FIG. 4b ,

In the FIGS. 5a-b In this regard, an improved embodiment of the gripper fingers is shown. 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 (15)

1. A gripping device for gripping and transporting a sheet-material stack, which has at least two gripping elements (21, 41) for gripping a sheet-material stack (1) disposed between the gripping elements, which are movable toward each other in order to grip the sheet-material stack (1) through a grip-clamping, wherein the gripping elements (21, 41) respectively have at least one gripping finger (22, 42) which can be laid against a stack end-sheet located at that end of the sheet-material stack facing the respective gripping element (21, 41) such that the gripping finger (22, 42) areally contacts the respective stack end-sheet, wherein at least one of the gripping fingers (22) of at least one of the gripping elements (21) is tiltable 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, into a tilted position (K), in which the gripping finger (22) is inclined toward the surface of the stack end-sheet (2) facing it, characterized in that
   at least the gripping fingers (22, 42) of one of the gripping elements (21, 41) are configured for a compensating motion which allows an adaptation of the position of the gripping fingers (22) to non-uniform sheet-material stacks, wherein the gripping fingers (22, 42) are fastened to the gripping element (21, 41) in such a way that they are movable, relative to the gripping element, along the direction perpendicular to the stack surface of the sheet-material stack (1), into mutually different positions.
2. The gripping device according to claim 1, characterized in that the tiltable gripping finger (22) is tiltable in such a way that the outer end of the tiltable gripping finger, which faces away from the fastening of the tiltable gripping finger at the gripping element (21), is inclined, by the tilting, toward the surface of the stack end-sheet (2) facing the tiltable gripping finger (22).
3. The gripping device according to any one of the preceding claims, characterized in that the tiltable gripping finger is tiltable around an axis (28) which is oriented approximately parallel to the surface of the stack end-sheet (2) facing the gripping finger and which encloses a non-zero angle with the direction of the gripping finger (22).
4. The gripping device according to any one of the preceding claims, characterized in that tilting the gripping finger (22) shifts the point of application of the gripping force of the tiltable gripping finger to a gripping spot which lies in the center region of the sheet-material stack (1).
5. The gripping device according to any one of the preceding claims, characterized in that when the one or more tiltable gripping fingers (22) are in the tilted position (K), the gripping elements (21, 41) exert a grip-clamping on the sheet-material stack (1), which is sufficient for firmly holding the sheet-material stack against its gravity through the grip-clamping.
6. The gripping device according to any one of the preceding claims, characterized in that the gripping element (21) having the tiltable gripping finger (22) is mechanically coupled with a belt (32), in order to move the gripping element (21) relative to the other gripping element (41) of the gripping device by the belt motion and in order to grip the sheet-material stack (1) disposed between the two gripping elements (21, 41) through a grip-clamping, wherein the gripping element (21) is mechanically constructed in such a way that the drive of the belt motion also makes available the force for tilting the tiltable gripping finger.
7. The gripping device according to any one of the preceding claims, characterized in that the gripping fingers configured for the compensating motion are fastened to the gripping element in such a way that they are movable against a spring force, relative to the gripping element, along the direction perpendicular to the stack surface.
8. The gripping device according to any one of the preceding claims, characterized in that the gripping element has two gripping fingers (22) which are formed by a fork which for the compensating motion is rotatable around an axis (27) which is oriented approximately parallel to the gripping fingers (22) and preferably lies approximately on the perpendicular bisector between the two gripping fingers (22).
9. The gripping device according to any one of the preceding claims, characterized in that the gripping device has a stopping mechanism for stopping the relative motion of the gripping elements (21, 41), in which the drive (30) of the relative motion is automatically switched off as soon as an opposing force of the sheet-material stack (1) generated upon the grip-clamping exceeds a certain value.
10. The gripping device according to claim 9, characterized in that the gripping device has a belt (32) which is mechanically coupled with one of the gripping elements (21), in order to move this gripping element relative to the other gripping element (41) of the gripping device through the belt motion and in order to grip the sheet-material stack (1) disposed between the two gripping elements through a grip-clamping, wherein the stopping mechanism includes that the belt tension is monitored by a sensor (33) which is arranged to stop the drive of the belt motion when a certain belt tension is exceeded.
11. The gripping device according to any one of the preceding claims, characterized in that the gripping device is arranged to remove a sheet-material stack from a container which has at least one side wall with a meandering surface, and that the gripping device has two gripping elements (21, 41) with respectively at least two gripping fingers (22, 42) which are configured to penetrate into recesses of the meandering surface of the side wall of the container.
12. The gripping device according to claim 11, characterized in that the side wall of the container, which has the meandering surface, has a projection-free section (102), so that the stack end-sheet of a sheet-material stack contained in the container can bulge out in this projection-free section (102) toward the side wall, and that at least one of the gripping fingers, which is provided for penetrating into this projection-free section of the side wall upon gripping the sheet-material stack, is beveled at its outer end in such a way that it can penetrate between the stack end-sheet (2) bulged out toward the side wall and the projection-free section (102).
13. An apparatus for processing sheet material, in particular value documents, which has a gripping device (10) according to any one of claims 1 to 12, wherein the gripping device (10) is arranged to insert the gripped sheet-material stack (1) into an input pocket of the apparatus and/or wherein the gripping device is arranged to remove the gripped sheet-material stack from an output pocket of the apparatus.
14. A method for gripping a sheet-material stack by means of a gripping device (10) according to any one of the preceding claims, for example for removing a sheet-material stack from a container (100), with the steps:

    - relatively moving the gripping elements (21, 41) toward each other through a relative motion of the gripping elements, in order to compress a sheet-material stack (1) disposed between the two gripping elements and to grip it through grip-clamping, wherein at least one of the gripping fingers of the gripping elements (21, 41) is tilted from its starting position (A) into its tilted position (K), and

    - automatically stopping the relative motion of the gripping elements (21, 41) as soon as a grip-clamping is achieved, in particular as soon as an opposing force of the sheet-material stack (1) generated upon the grip-clamping exceeds a predetermined value, and

    - transporting the sheet-material stack (1) gripped through the grip-clamping by means of the gripping device (10), wherein the grip-clamping for example removes the gripped sheet-material stack (1) from the container, wherein

    at least the gripping fingers (22, 42) of one of the gripping elements (21, 41) are configured for a compensating motion which allows an adaptation of the position of the gripping fingers (22) to non-uniform sheet-material stacks, wherein the gripping fingers (22, 42) are fastened to the gripping element (21, 41) in such a way that they are movable, relative to the gripping element, along the direction perpendicular to the stack surface of the sheet-material stack (1), into mutually different positions.
15. The method according to claim 14, characterized in that after the stopping of the relative motion the relative motion of the gripping elements (21, 41) remains stopped for a certain waiting period, and that after the waiting period a subsequent gripping of the sheet-material stack (1) is carried out, upon which the relative motion of the gripping elements (21, 41) toward each other is started anew in order to produce a reliable grip-clamping of the sheet-material stack also in the case of a relaxation of the sheet-material stack (1).

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