Gripping device for gripping sheet material

Abstract

A gripping device for gripping a sheet-material stack has at least two gripping elements for gripping a sheet-material stack disposed between the gripping elements, which gripping elements can be moved toward each other in order to grip the sheet-material stack. At least one of the gripping fingers of one of the gripping elements is tiltable from its starting position, in which it is oriented substantially parallel to the stack surface, into a tilted position, in which it is inclined toward the stack surface. With the gripping device any types of sheet-material stacks can be reliably and trouble-free removed from a container and held against gravity through grip-clamping.

Claims

1. A gripping device for gripping and transporting a sheet-material stack, which has at least two gripping elements for gripping a sheet-material stack disposed between the gripping elements, which are movable toward each other in order to grip the sheet-material stack through a grip-clamping, wherein the gripping elements respectively have at least one gripping finger which can be laid against a stack end-sheet located at that end of the sheet-material stack facing the respective gripping element such that the gripping finger aereally contacts the respective stack end-sheet, wherein at least one of the gripping fingers of at least one of the gripping elements is tiltable from a starting position (A), in which the gripping finger is oriented substantially parallel to the surface of the stack end-sheet facing it, into a tilted position (K), in which the gripping finger is inclined toward the surface of the stack end-sheet facing it, wherein the gripping device has a stopping mechanism for stopping the relative motion of the gripping elements, in which the drive of the relative motion is automatically stopped as soon as an opposing force of the sheet-material stack generated upon the grip-clamping exceeds a certain value, and wherein the gripping device has a belt which is mechanically coupled with one of the gripping elements, in order to move this gripping element relative to the other gripping element of the gripping device through the belt motion and in order to grip the sheet-material stack disposed between the two gripping elements through a grip-clamping, wherein the stopping mechanism includes that the belt tension is monitored by a sensor which is arranged to stop the drive of the belt motion when a certain belt tension is exceeded.

2. The gripping device according to claim 1, wherein the tiltable gripping finger 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, is inclined, by the tilting, toward the surface of the stack end-sheet facing the tiltable gripping finger.

3. The gripping device according to claim 1, wherein the tiltable gripping finger is tiltable around an axis which is oriented approximately parallel to the surface of the stack end-sheet facing the gripping finger and which encloses a non-zero angle with the direction of the gripping finger.

4. The gripping device according to claim 1, wherein tilting the gripping finger 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.

5. The gripping device according to claim 1, wherein when the one or more tiltable gripping fingers are in the tilted position, the gripping elements exert a grip-clamping on the sheet-material stack, which is sufficient for firmly holding the sheet-material stack against its gravity through the grip-clamping.

6. The gripping device according to claim 1, wherein the gripping element having the tiltable gripping finger is mechanically coupled with a belt, in order to move the gripping element relative to the other gripping element of the gripping device by the belt motion and in order to grip the sheet-material stack disposed between the two gripping elements through a grip-clamping, wherein the gripping element is mechanically designed 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 claim 1, wherein at least the gripping fingers of one of the gripping elements are configured for a compensating motion which allows an adaptation of the position of the gripping fingers to non-uniform sheet-material stacks, wherein the gripping fingers are fastened to the gripping element in particular 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, into mutually different positions.

8. The gripping device according to claim 7, wherein the gripping element has two gripping fingers which are formed by a fork which for the compensating motion is rotatable around an axis which is oriented approximately parallel to the gripping fingers and preferably lies approximately on the perpendicular bisector between the two gripping fingers.

9. The gripping device according to claim 1, wherein 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 with respectively at least two gripping fingers which are configured to penetrate into recesses of the meandering surface of the side wall of the container.

10. The gripping device according to claim 9, wherein the side wall of the container, which has the meandering surface, has a projection-free section, so that the stack end-sheet of a sheet-material stack contained in the container can bulge out in this projection-free section 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 bulged out toward the side wall and the projection-free section.

11. An apparatus for processing sheet material, in particular value documents, which has a gripping device according to claim 1, wherein the gripping device is arranged to insert the gripped sheet-material stack 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.

12. A method for gripping a sheet-material stack by means of a gripping device according to claim 1, for example for removing a sheet-material stack from a container, with the steps: relatively moving the gripping elements toward each other through a relative motion of the gripping elements, in order to compress a sheet-material stack 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 is tilted from its starting position into its tilted position, and automatically stopping the relative motion of the gripping elements as soon as a grip-clamping is achieved, in particular as soon as an opposing force of the sheet-material stack generated upon the grip-clamping exceeds a predetermined value, and transporting the sheet-material stack gripped through the grip-clamping by means of the gripping device, wherein the grip-clamping for example removes the gripped sheet-material stack from the container.

13. The method according to claim 12, wherein after the stopping of the relative motion the relative motion of the gripping elements remains stopped for a certain waiting period, and that after the waiting period a subsequent gripping of the sheet-material stack is carried out, upon which the relative motion of the gripping elements 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.

14. A gripping device for gripping and transporting a sheet-material stack, which has at least two gripping elements for gripping a sheet-material stack disposed between the gripping elements, which are movable toward each other in order to grip the sheet-material stack through a grip-clamping, wherein the gripping elements respectively have at least one gripping finger which can be laid against a stack end-sheet located at that end of the sheet-material stack facing the respective gripping element such that the gripping finger aereally contacts the respective stack end-sheet, wherein at least one of the gripping fingers of at least one of the gripping elements is tiltable from a starting position (A), in which the gripping finger is oriented substantially parallel to the surface of the stack end-sheet facing it, into a tilted position (K), in which the gripping finger is inclined toward the surface of the stack end-sheet facing it, wherein at least the gripping fingers of one of the gripping elements are configured for an automatic compensating motion which allows an adaptation of the position of the gripping fingers to a single non-uniform sheet-material stack, wherein the gripping fingers are fastened to the gripping element in particular 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, into mutually different positions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter the invention will be explained by way of example with reference to the following Figures. There are shown:

(2) FIG. 1a-b a container partly filled with bank notes, together with a per se known gripper (FIG. 1a) and a container together with gripping elements of a gripping device of the invention (FIG. 1b),

(3) FIG. 2a-d gripping device of the invention at various points in time, when one of the gripping elements is moved toward the other,

(4) FIG. 3a-b gripping device upon gripping a leftward-yielding bank note stack (FIG. 3a) or upon gripping a rightward-yielding bank note stack (FIG. 3b),

(5) FIG. 4a-b gripping element with conventional gripping fingers, and

(6) FIG. 5a-b specially configured gripping element for reliably gripping the bank notes.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

(7) FIG. 1a shows a container 100 partly filled with bank notes together with a per se known gripper 9. The container 100 is formed of a housing closed on five sides, which has several subdivisions which can receive separating elements 101 in an interchangeable fashion. Between the meandering separating elements 101 bank note stacks 1 can be input. The bank notes are input such that they stand on their longitudinal edges in the container 100. This enables a reliable and ergonomically favorable filling of the container. For bank notes to be automatically removed from the container 100 the gripper 9 is lowered into the container 1, the gripping elements thereof penetrating into the recesses of the separating elements 101. After the lowering the two gripping elements of the gripper 9 are moved toward each other to grip a bank note stack 1 and lift it from the container.

(8) In FIG. 1b there is also represented a container 100 for receiving bank notes standing on their longitudinal edges (the bank note stack 1 is not shown in FIG. 1b). For removing the bank notes, a gripping device 10 having two gripping elements 21, 41 according to the invention is employed, which can be moved toward each other and away from each other. The gripping elements 21, 41 are part of the gripping device 10 which will be described in detail with reference to the FIGS. 2a-d and from which only the two gripping elements 21, 41 are shown in FIG. 1b. To enable the bank note stack 1 located in the container to be reliably gripped and later deposited, at least one of the gripping elements substantially extends over the entire inside width of the container 100. Additionally, the gripping device 10 can have sensors for the positioning of the gripping elements 21, 41, whose signals are evaluated by a control device in order to control the motion of the gripping device 10.

(9) For example, in each container all the bank notes are aligned with their side edges with the same side wall of the respective container 100. This achieves that the gripping elements 21, 41 can grip the respective bank note stack 1without adaptation of the lateral position of the gripping elements 21, 41always at the same gripping spots (with regard to the bank note stack). The lateral position of the gripping element 21 in FIG. 1b is e.g. to the right of the container center and chosen such that the two gripping spots are disposed on both sides of and symmetrically to the center of the smallest possible bank note format, if the bank notes are aligned with the right side wall of the container 100. If the bank notes are always aligned with the right side wall, these gripping spots with regard to the smallest possible bank note format lie at the same positions in each bank note stack.

(10) The separating elements 101 are equipped with a meandering surface on both sides, so that the gripping elements 21, 41 can penetrate in a defined manner between bank notes located in the container 100 in order to grip a bank note stack and to remove it from the container 100. The arrangement and extension of the gripping fingers of the gripping elements 21, 41 are adapted to the meandering form of the separating elements 101, so that they can penetrate into the recesses of the meandering surface. Similar to the separating elements, also the front and rear inner walls of the container have a meandering surface with projections and recesses, which also enables the penetration of the gripping fingers of the gripping elements.

(11) The bank note stack 1 removed from the container 100 by the gripping device 10 is then supplied to a processing for example by means of a bank note processing apparatus. For this purpose, the gripping device 10 inserts the bank note stack into an input pocket of the bank note processing apparatus, from which the bank notes are transported away individually by means of a singler. For this purpose, the gripping device 10 is disposed in the region of the input pocket of the bank note processing apparatus, so that bank notes removed from the container 100 can be inserted into an input pocket. Within the range of the gripping device 10 there can be provided a suitable receiving means for one or several containers 100. Then, the bank notes are processed in the bank note processing apparatus, deposited in output pockets of the bank note processing apparatus and brought to account.

(12) FIG. 2a shows a gripping device 10 having the two gripping elements 21 and 41 according to the invention. For gripping a bank note stack 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 slide 24 which is mechanically coupled with a belt 32 of the gripping device 10. Through the motion of the belt 32 the gripping element 21 can be moved linearly toward the gripping element 41 and away from it. The belt 32 is moved by a motor 30 which drives the drive roller 31 of the belt. The stationary gripping element 41 has a plurality of gripping fingers 42, which are distributed over the entire length of the bank note stack. The stationary gripping element can alternatively also have less gripping fingers. The movable gripping element 21 in this example merely has two gripping fingers 22. But, alternatively, for the movable gripping element there can also be employed, instead of the two gripping fingers 22, one single wide gripping finger or more than two gripping fingers. Also the movable gripping element 21 can have a plurality of gripping fingers 22 which are distributed over the entire length of the bank note stack.

(13) In FIGS. 2a-d the gripping device 10 is shown at various points in time, when the gripping element 21 is moved continuously or step by step toward the other gripping element 41, in order to grip the bank note stack 1. In FIG. 2a, the gripping element 21 is moved toward the stack end-sheet 2 of the bank note stack 1, but not yet contacts this. In FIG. 2b the point in time of the contact between gripping element 21 and stack end-sheet 2 is represented. FIG. 2c shows a point in time at which the bank note stack 1 is already pressed against the gripping element 41 by the gripping element 21, but the gripping fingers 22 are still in their untilted starting position A. FIG. 2d shows the gripping device, after the gripping fingers 22 have been tilted into their tilted position K and the bank note stack 1 is gripped.

(14) The gripping fingers 22 of the gripping element 21 are tiltable toward the bank note stack 1 by a mechanical tilting mechanism which the gripping element 21 has. The function of the tilting mechanism is illustrated by a comparison of the FIGS. 2c and 2d. Starting out from FIG. 2c, in which the gripping fingers 22 are in their untilted starting position A, the slide 24 of the gripping element 21 is moved further to the left by means of the belt 32. Upon the further motion of the gripping element 21 an opposing force is exerted on the gripping fingers 22 by the bank note stack 1, which opposing force prevents the gripping fingers 22 and the bottom member 23 of the gripping element 21 connected therewith from following the leftward motion of the slide 24. The further motion of the slide 24 to the left and the opposing force of the bank note stack 1 on the gripping fingers 22 and on the bottom member 23 leads to a torque acting on the side part 25 of the gripping element 21, which is accordingly mounted at the slide 24 and at the bottom member 23. The side part 25 is thereby rotated counterclockwise by an angle. Through the rotation of the side part 25 the bottom member 23 of the gripping element, which is mounted on the left side thereof, is rotated clockwise. The gripping fingers 22 fastened to the bottom member 23 are tilted into their tilted position K, e.g. by a tilting angle of few degrees around the axis 28, by the rotation of the bottom member 23, cf. FIG. 2d. The rotation of the bottom member 23 is counteracted by the force of the spring 26, which is tensioned by the rotation of the bottom member 23. For releasing the bank note stack 1 the gripping elements 21, 41 are moved apart. As soon as the opposing force of the bank note stack 1 ceases, the gripping element 21 returns to its original state through the force of the spring 26, the gripping fingers 22 returning to their untilted starting position A.

(15) Additionally or alternatively to the just described purely mechanically controlled tilting mechanism, also an electronic triggering and controlling of the tilting mechanism of the gripping fingers is possible, e.g. with the aid of corresponding actuators for tilting the gripping fingers and sensors. For this purpose, there can be employed sensors which detect the position of the movable gripping element and/or which upon the compressing of the stack detect the opposing force of the bank note stack, in order to trigger the tilting of the gripping fingers and to stop the relative motion of the gripping elements.

(16) If the bank note stack to be gripped is located in a container, such as e.g. the container 100 of FIG. 1b, the movable gripping element 21 is moved, in a lifted position of the gripping device 10, toward the stationary gripping element 41 (FIG. 2a, FIG. 2b), i.e. before the gripping elements are lowered into the container 100. Only when the position of the two gripping elements 21, 41 is correct for penetrating into the recesses of the respective meandering surface, the gripping device 10 is lowered into the container 100. This lowering takes place between the points in time shown in the FIGS. 2b and 2c. After the gripping fingers having penetrated into the recesses of the separating elements 101 or the inner wall of the container 100, the movable gripping element 21 is further moved toward the gripping element 41, in order to compress the bank note stack 1 (FIG. 2c) and tilt the gripping fingers 22 (FIG. 2d). The bank note stack 1 is thus gripped and can then be reliably lifted from the container 100.

(17) The gripping device 10 has e.g. a mechanically controlled stopping mechanism for automatically stopping the motion of the gripping element 21 as soon as an opposing force of the sheet-material stack 1 generated upon the gripping 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 disposed in that section along the belt 32, in which in the case of the grip-clamping of the sheet-material stack, upon the further motion of the gripping element 21, an increased belt tension is generated through the opposing force of the sheet-material stack 1. In the FIGS. 2a-d, this is the section of the belt 32 which along the moving direction of the belt lies between the slide 24 of the gripping device 21 and the drive roller 31.

(18) The sensor has a roller 34 which for monitoring the belt tension is pressed against the belt with a spring. In the case of the grip-clamping of the sheet-material stack 1 the belt tension in the region of the roller 34 is increased through the opposing force of the sheet-material stack 1 acting during the further motion of the gripping element 21 and through the driving power of the drive roller 31. Through the increased belt tension the roller 34 is deflected against the spring force by the belt 32 (compared to FIG. 2c, the roller 34 in FIG. 2d is deflected slightly upward). The deflection of the roller 34 is monitored e.g. by a proximity sensor 33 which monitors the position of the roller e.g. inductively or capacitively. If a certain deflection of the roller 34 is exceeded, the proximity sensor 33 switches off the motor 30 employed for driving the belt, so that the motion of the gripping element 21 is automatically stopped. The motor 30 is preferably a motor with self-locking gearing, so that the grip-clamping of the bank note stack 1 is also maintained when the motor 30 is switched off. When the gripping elements 21, 41 are moved apart, the roller 34 is again pressed, as soon as the belt tension is normal again, against the belt 32 by the spring force counteracting the deflection.

(19) In the case of bank note stacks, foil elements of the bank notes, e.g. security elements which are applied on the bank notes, may lead to a non-uniform stack height and/or to non-uniform mechanical properties of the bank note stack 1. Because the foil elements can lead to a local arching of the bank notes in a certain region or increase the local thickness of the bank notes. With the plurality of bank notes in a bank note stack, altogether there arise bank note stacks with an oblique or wavy surface or which in dependence on the position along the stack surface have a different elasticity and thus provide a locally different opposing force, cf. FIGS. 3a-b.

(20) In order to reliably grip even these bank note stacks, in a preferred embodiment at least one of the gripping elements (the one which also has tiltable gripping fingers and/or the other gripping element) is configured to perform a compensating motion which allows the gripping element to adapt to non-uniform sheet-material stacks. This is explained hereinafter with the example of the gripping element 21. For gripping the bank note stack, the two gripping fingers 22 of the gripping element 21 are disposed on both sides of the center M of the bank note stack 1, cf. FIG. 2c. The gripping fingers 22 are fastened to the bottom member 23 of the gripping element 21 such that they are movable, relative to the bottom member 23, along the direction perpendicular to the stack surface of the sheet-material stack 1, into mutually different positions. This compensating motion of the gripping fingers is independent of the tilting motion, shown in the FIGS. 2c-d, for tilting the gripping fingers.

(21) In the example of the FIGS. 3a-b the gripping fingers 22 are formed by a fork. This fork is rotatably mounted at an axis 27 which is oriented approximately parallel to the gripping fingers 22 and which lies approximately on the perpendicular bisector between the two gripping fingers, cf. FIGS. 3a-b. The two gripping fingers 22 are thus deflectable perpendicular to the stack surface into various positions. Upon gripping a stack having a non-uniform height or non-uniform mechanical properties the gripping fingers thus move in opposite directions. The spring force of the spring 26 counteracts the rotation of the gripping fingers 22 around the axis 27. In FIG. 3a the gripping device 10 grips a sheet-material stack 1, whose left side has a higher elasticity than its right side, so that the gripping fingers 22 upon compressing the stack are automatically slightly rotated counterclockwise around the axis 27. In FIG. 3b the gripping device 10 grips a different sheet-material stack 1, whose right side has a higher elasticity than its left side, so that the gripping fingers 22 are slightly rotated clockwise around the axis 27.

(22) In the FIGS. 4a-b the gripping element 41 is shown upon penetrating into the recesses of the meandering surface of a separating element 101 contained in a bank note container 100. For the bank note stack to be more easily manually removed from and inserted into the container 100, the separating element 101 has a projection-free section 102, at which the meandering form is interrupted and which has a recessed handle. A bank note BN, e.g. the stack end-sheet 2 of a bank note stack 1 received in the container, can bulge out in this projection-free section 102, cf. FIG. 4a. When the gripping element 41 is lowered there thus exists the danger that the two gripping fingers 42 hitting this projection-free section 102 do not penetrate into the slit between the bank note BN and the separating element 101 but hit the face of the bank note BN and damage this, cf. FIG. 4b.

(23) In the FIGS. 5a-b there is shown an embodiment of the gripping fingers, which is improved in this regard. The two gripping fingers 42, which upon gripping the sheet-material stack are provided for penetrating into the projection-free section 102, are beveled at their outer ends. The bevel is such that the thickness of the gripping finger, which this has perpendicular to the direction of the gripping finger, decreases along the direction pointing toward the center of the projection-free section 102. Thus, these gripping fingers can penetrate between the bulged out bank note BN and the projection-free section 102 without problems, cf. FIG. 5b. Also in the case of a bank note bulging out in a projection-free section, this bank note or the stack can therefore be reliably gripped without damaging bank notes.