BE1020390A3 - DEVICE FOR ARRANGING PLASTER STONES ON A PALLET OR OTHER DOCUMENT. - Google Patents

Description

Apparatus for placing paving stones on a pallet or other substrate

The invention relates to a device for arranging paving stones, in particular used paving stones, in a specific laying pattern on a pallet or other base according to the preamble of claim 1.

Paving stones, such as concrete paving stones, are shaped stones that are known to be used for paving paths, roads, yards, etc. The paving stones, which are in particular cuboid, but may also have other shapes, are usually in a certain laying pattern on a planum, d. H. a flat sand or grit bed, put on. Known laying patterns are series dressings, diagonal dressings, herringbone patterns or patterns in which the longitudinal axes of adjacent paving stones run at right angles to one another.

In order to not have to lay paving stones of this kind laboriously by hand, paving stone laying devices, also known as laying tongs, are known. Such installation pliers grasp an entire paving stone layer of paving stones usually delivered on pallets, transport the paving stone layer taken to the intended laying site and place the paving stones there close to each other on the subgrade. The use of such installation pliers laying the paving stones can be significantly accelerated and facilitated. However, a prerequisite for the use of such laying tongs is that arranged by the laying tongs paving stones on the pallet, d. H. be close to each other lying in a specific orientation and arrangement.

Used paving stones, which are not supplied by the factory, but are removed from existing roads, roads, etc., are usually disordered in containers or in piles. If such paving stones are to be reused and laid using installation pliers, it is thus necessary to arrange the paving stones in layers and in the same or similar manner as is the case with new paving stones which are supplied on pallets by the manufacturer.

From EP 1 975 320 A2 a device for arranging used paving stones in a variable laying pattern on a pallet or other base, for example a storage table, according to the preamble of claim 1 is known. This device has a filling container into which the paving stones can be filled, for example by means of a lift truck. From the filling container, the paving stones arrive on conveyor belts to a cleaning device and into an inspection area in order then to place them on a delivery table in a predetermined position and orientation as a function of their position on the conveyor belt by means of a transfer device.

However, this known device is complicated and expensive. There are robot-like devices are used, each of which remove a single paving stone from the conveyor belt and store in the desired orientation on the storage table. However, this is with a relatively low workload, d. H. a low throughput, connected.

The invention has for its object to provide a device of the type mentioned above, on the one hand high performance and on the other hand, a large variability in the orientation of the

Paving stones on a pallet or other surface allows.

This object is achieved by a device having the features of claim 1. Advantageous embodiments of the invention are described in the further claims.

In the device according to the invention, a gripping device is provided, which has a plurality of gripper units attached to a gripper holder, with each of which a paving stone can be gripped. Furthermore, a position changing device acting between the gripper holder and the gripping units is provided with a distance changing device for changing the mutual spacing of the gripping units and / or with an angle adjusting device for changing the angle between the gripping units and the gripper holder, so that the mutual positioning between the cobblestone receiving area and the cobblestone discharge area the gripped paving stones is changeable.

The word "grasp" or the suffixes "gripper" and "gripper" are to be understood in the context of the invention in its most general meaning and not limited to that a clamping action or a positive connection is generated. The word "gripping device" thus also includes such devices in which the paving stones are "grabbed" and implemented with suckers. Accordingly, a "gripper holder" also includes a holder for suction units. "Gripper units" also include suction units.

Since the gripping device according to the invention comprises a plurality of gripping units, in particular three, four or five gripping units, a corresponding number of paving stones can be implemented simultaneously in one operation. This increases the workload accordingly. Furthermore, the individual gripping units can be moved and / or pivoted on the gripper holder such that the paving stones in variable

Alignments on the pallet or other pad can be discontinued. For example, it is possible to place the stones at an angle of + 45 ° on a pallet during a transfer process, while in the subsequent operation, the paving stones are placed at an angle of -45 ° on the pallet. A particularly universally applicable, variable device results when both a distance changing device and an angle adjustment for the gripping units is present. Furthermore, the device may include a storage table on which a pallet is deposited and which is pivotable about a vertical axis. In this way, the storage table and thus the pallet can be rotated relative to the gripping device, which allows additional variability with regard to the depositing position of the paving stones on the pallet.

According to an advantageous embodiment of the gripper holder is in the form of a carriage or carriage, which is movable or displaceable on rails between the paving stone receiving area and the paving stone delivery area. This makes it possible to realize a particularly stable, precisely operating gripping device with high performance in a relatively simple manner.

According to an advantageous embodiment, the distance changing device comprises at least one guide rail arranged along the gripper holder, on which the gripping units are displaceably mounted, and a sliding device for displacing the gripping units along the guide rail, wherein the sliding device is in operative connection with at least a part of the gripping units. It is particularly advantageous if two parallel guide rails are arranged, since then the gripping units can be kept in a particularly stable, low-backlash manner.

According to an advantageous embodiment, the gripping units are pivotable about mutually parallel pivot axes and have lateral

Boom on which push rods of the angle adjustment are hinged to articulation points, which are laterally offset to the pivot axes. In such an embodiment, the angular adjustment of the gripping units can be made jointly by means of a common shaft, in particular splined shaft, wherein pivoting levers are provided which are slidably supported on the shaft, but rotatably supported and hingedly connected to the push rods. This displacement of the pivot lever ensures that the angle adjustment can also be used in such gripping devices in which the distance between the individual gripping units can be changed.

According to an advantageous embodiment, each gripping unit comprises in each case a gripping tongs for clamping the paving stones and an actuating cylinder for opening and closing the gripping tongs. This results in a large variability in terms of the use of the gripping units, since the gripping units can be operated individually. This is particularly advantageous if only a portion of the gripping units in individual Umsetzvorgängen should receive paving stones depending on the desired laying pattern, while the remaining gripping units should remain unoccupied.

According to an advantageous embodiment, the conveying device comprises a transfer area with a V-shaped guideway for the paving stones, wherein the guideway is formed by two rows of support elements, in particular guide rollers, which are arranged to each other in particular at an angle of 90 °. In this way, a transfer area of the conveyor can be created in a simple manner in which the paving stones are provided in a precisely predetermined orientation.

It is particularly advantageous if a lifting device for the paving stones is arranged in the region of the transfer area of the conveyor, in which the paving stones can be brought into a position lifted from the support elements of the conveyor in which they are gripped by the gripping units.

A particularly space-saving arrangement can be achieved if the lifting device has lifting elements which can be inserted in intermediate spaces between the support elements of the conveyor.

According to an advantageous embodiment, the lifting device has lifting elements, which are coupled in a coupled manner with stop elements which are movable into the conveying space of the transfer area of the conveying device in order to determine the final position of the paving stones in the transfer area. In this case, the lifting of a lifting element or a Hubelementgruppe automatically causes the stop for the subsequent paving stone is activated, so that the subsequent paving stones are kept at a certain distance from the respective front paving stone.

The invention will be explained in more detail by way of example with reference to the drawings. Show it:

FIG. 1 shows a somewhat reduced representation of the gripping device of the device according to the invention,

FIG. 2 shows an illustration of the transfer area of the conveyor with a lifting device, wherein one lifting unit is in the raised position and the other lifting units are in the lowered position,

FIG. 3 shows a representation according to FIG

Lifting units are in the raised position,

Figure 4: two lifting units in isolation,

FIG. 5 shows the lifting units of FIG. 4 together with a holding frame,

FIG. 6 shows a gripper holder with gripping units during the transfer of the

Paving stones,

FIGS. 7-9: a gripping unit in different positions,

FIG. 10 shows a distance changing device together with FIG

Gripper units,

Figure 11: a gripping unit with console, and

Figures 12,13: similar views as Figure 10, but from a different angle, wherein the gripping units are aligned at different angles to the gripper holder.

Figures 1 to 3 show a gripping device 1 for transferring paving stones 2 (molded bricks) from a transfer area 15 of a conveyor 3 to a storage point spaced therefrom, in particular to a pallet, not shown, to the paving stones in a certain laying pattern, d. H. in a specific arrangement and orientation, to be arranged on the pallet.

The transfer area 15 of the conveyor 3 has a V-shaped guideway for the paving stones 2. The guideway is formed by two rows of at least partially driven guide rollers 66 which are rotatably mounted at an angle of 90 ° to each other in a holding frame 67.

Furthermore, Figures 1 to 5 show parts of a lifting device 4, with which the paving stones 2 can be raised slightly by the conveyor 3 and brought into a position in which the paving stones 2 can be gripped by gripping tongs 5 of the gripping device 1. After gripping the paving stones 2, the gripping device 1 can then be moved on rails 6 in the direction of the deposit, where the gripper tongs 5 are opened and the paving stones 2 are stored in a manner not shown on the pallet.

For this purpose, the gripping device 1 has a gripper holder 7, on which a total of five gripper units 8 are slidably mounted. The gripper holder 7 extends like a portal from one of the rails 6 to the other. In the end regions of the gripper holder 7 rollers 9 are rotatably mounted, which over-grip the rails 6 and under and the gripper holder 7 also lead laterally. The gripping device 1 is thus designed as a carriage. Alternatively, the gripping device 1 could be slidably mounted on the rails 6 and thus formed as a carriage.

The drive for the movement of the gripping device 1 along the rails 6 via a motor 10. The motor 10 is fixed to the top of the gripper holder 7 and offset a drive shaft 11 in rotary motion. The drive shaft 11 is connected in its end portion 12 in a manner not shown, for example, with a drive belt which pulls the gripping device 1 along the rails 6 upon rotation of the drive shaft 11.

The gripping units 8 are, as can be seen in particular from FIGS. 10 to 13, supported by brackets 13 so as to be displaceable on two parallel guide rails 14. The guide rails 14 extend parallel to the longitudinal direction of the gripper holder 7 and thus parallel to the longitudinal direction of the transfer region 15 of the conveyor 3 at least over a substantial part of the total length of the gripper holder. 7

The brackets 13 have on their upper side sliding base 16 (Figure 11), which are slidably engaged with the guide rails 14. At downwardly projecting retaining tabs 17, the brackets 13 have spline bearings 18 for rotatably supporting a splined shaft 19. The spline shaft 19 extends parallel to the guide rails 14 at least over a substantial part of the total length of the gripper holder 7. The spline bearings 18 allow a displacement of the brackets 13 along the spline 19th

At the top of the brackets 13, a base 20 is fixed, which carries a coupling pin 21. These coupling pins 21 are used, as can be seen in particular from FIG. 10, for the articulated coupling of sliding strips 22, which are part of a distance changing device with which the mutual spacing of the gripping units 8 can be changed.

For this purpose, each gripping unit 8 is assigned its own slide bar 22. These slide bars 22 are hinged at their other end to a common lever 23 which is pivotable about a central, vertical pivot axis 24. The articulation points, which are designated in FIG. 10 with 25a-25d, are arranged at a distance from one another along the lever 23. In this way, when the lever 23 is pivoted about the pivot axis 24, those gripping units 8 whose articulation points 25a, 25d have the greater distance from the pivot axis 24, along the guide rails 14 further displaced than those gripping units 8, the articulation points 25b, 25c for Swivel axis 24 are closer. By pivoting the lever 23 about the pivot axis 24 thus the mutual distance of the gripping units 8 along the guide rails 14 can be changed.

In the illustrated embodiment, only the two left and the two right gripping units 8 are displaceable by means of the lever 23. Overall, however, all gripping units 8 are slidably mounted on the guide rails 14.

For pivoting the lever 23, this has an elbow 26, whose outer peripheral surface describes a circular arc about the pivot axis 24 around. An unillustrated drive belt is attached to the two ends 26a, 26b of the elbow 26 and is passed between two adjacently disposed pulleys 27 therethrough to be led around from there to a drive shaft 28 of an electric motor 29. The pulleys 27 cause the drive belt with a relatively large wrap angle with the drive shaft 28 is engaged. Conveniently, the drive belt is a toothed belt. If the drive shaft 28 is rotated by the electric motor 29 in rotation, the lever 23 is pivoted depending on the direction of rotation of the drive shaft 28 in a clockwise or counterclockwise direction.

In order also to align the gripping units 8, d. H. the angle that the gripping units 8 take to the longitudinal direction of the gripper holder 7 to change, the individual gripping units 8 are pivotally mounted on the brackets 13. The pivot axis, which is designated by 30 in FIG. 11, extends vertically. This pivot bearing is designed such that the gripping units 8 can be pivoted from the central position shown in Figure 10 at least 45 ° to each side, so that there is a total pivoting range of at least 90 ° about the pivot axis 30. In this way, the paving stones 2 can also be deposited on a pallet in such a way that the longitudinal axes of adjacent paving stones form an angle of 90 ° relative to one another.

The pivotal mounting of the gripping units 8 on the brackets 13 takes place by means of a bearing pin 31, which is mounted perpendicular to a support plate 32 of the gripping unit 8. At this support plate 32, as will be described in more detail below, retaining cheeks 33 are fixed, on the one hand for supporting an actuating cylinder 34 and on the other hand to the articulated

Storage of grippers 5 serve, as will be described later.

The angular adjustment of the gripping units 8 relative to the guide rails 14 by means of an angle adjustment, which includes the spline shaft 19. As can be seen from FIGS. 12 and 13, the angle adjustment device further comprises pivoting levers 35, which are mounted longitudinally displaceably but non-rotatably on the splined shaft 19. At the pivot levers 35 actuating rods 36 are articulated, which are pivotally connected at its opposite end with a lateral arm 37 of the support plate 32. The corresponding hinge point 38 is thus laterally offset from the pivot axis 30.

If the pivot levers 35 are pivoted between those shown in Figures 12 and 13 positions by means of the spline 19, it is due to this Winkelverstelleinrichtung thus to a corresponding angular adjustment of the gripping unit 8 between + 45 ° and -45 ° relative to the 0 ° orientation, in Figure 10 is shown.

The rotation of the spline shaft 19 is effected by means of at least one actuating cylinder, not shown, which is rotatably connected via a pivot lever which corresponds to the pivot levers 35 with the spline 19, so that a retraction or extension of the piston rod of the actuating cylinder a corresponding pivoting of the spline 19 causes.

Due to the displaceable arrangement of the retaining tabs 17 and the pivot lever 35 on the spline shaft 19, the gripping units 8 can be moved along the guide rails 14, without this would affect the function of the angle adjustment.

The construction and function of the gripping units 8 with the gripping tongs 5 will be described in more detail below with reference to FIGS. 7-9, 11.

The gripping tongs 5 have a first gripping jaw 39, which consists of two parallel, spaced gripping jaw parts 39a, 39b. The first gripping jaw 39 is pivotally mounted about a horizontal pivot axis 40 on the two retaining cheeks 33, in the intermediate space of which the first gripping jaw 39 extends into it. In Figures 7-9, only the rear retaining cheek 33 is shown, while the front retaining cheek has been omitted for clarity. Furthermore, the first jaws 39 are formed substantially L-shaped, wherein the two legs at least in that region which comes into contact with the paving stones 2, mutually perpendicular bearing surfaces 57, 58 have.

On the first gripping jaw 39, a second, L-shaped gripping jaw 41 is pivotably mounted about a horizontal pivot axis 42. This second jaw 41 consists of two parallel, mutually spaced gripping jaw parts 41a, 41b. Furthermore, the second gripping jaw 41 extends into the intermediate space between the gripping jaw parts 39a, 39b.

The actuating cylinder 34 has a piston rod 43, which is coupled at its front end by means of a horizontal axle bolt 44 with the second gripping jaw 41. The end portions of this axle bolt 44 extend laterally beyond the second jaw 41 and are guided in an arcuate slot 45 slidably. The slot 45 describes a circular arc around the pivot axis 42 around.

The actuating cylinder 34 is arranged between the two retaining cheeks 33. Furthermore, the upper end of the actuating cylinder 34 is supported at the upper end of the retaining cheeks 33, d. H. articulated.

As can be seen from FIGS. 7-9, the gripping tongs 5 can be moved by means of the

Actuator cylinder 34 is pivoted from a raised position, which is shown in Figure 7, in a lowered position, which is shown in Figure 9. In Figure 7, the piston rod 43 is retracted. The first jaw 39 is pulled by means of the axle bolt 44 upwards. If then, as can be seen from FIG. 8, the piston rod 43 is slightly extended, first both gripping jaws 39, 41 together, without the mutual position thereof changing, are pivoted downwards about the pivot axis 40. The jaws 39, 41 are hereby opened, d. H. the free legs 46, 47 of the jaws 39, 41 are spaced apart from each other.

If the piston rod 43 is subsequently extended further, as shown in FIG. 9, the second gripping jaw 41 is pivoted down about the pivot axis 42, as a result of which the end-side limbs 46, 47 are approaching. A paving stone 2 arranged between these legs 46, 47 can thereby be clamped.

From FIG. 11, it can further be seen that the gripping units 8 have pressing plates 48, which are arranged laterally next to the first gripping jaw 39 and are pivotably mounted on the holding cheeks 33 about the pivot axis 40. These pressure plates 48 serve to press the paving stones 2 when depositing on a pallet against already deposited paving stones when the gripping tongs 5 are opened. This prevents that the paving stones 2 to be deposited are undesirably moved back by the first gripping jaw 39 when the gripping tongs 5 are opened. For this purpose, the pressure plates 48 extend into a lower part of the first gripping jaw 39 and there have arcuate slots 50 in which driving pins 51 which project laterally from the first gripping jaw 39 can move. Furthermore, the pressure plates 48 above the pivot axis 40 end portions 52, which are pulled by means of a tension spring, not shown, which is fixed to a transverse web 53 in the direction of the transverse web 53. Because of this spring preload the Andrückbleche 48 remain when opening and pivoting back of the gripper 5 initially in the position shown in Figure 11 until the drive pins 51 abut the rear end of the arcuate slot 50 and the gripper 5 has given the paving stone 2 free. If the gripping tongs 5 are further swung upwards, the driving pins 51 also carry the pressure plates 48, so that the lower end region of the pressure plates 48 is swung upwards to the rear.

So that the gripping tongs 5 can take over the paving stones 2 arranged in the same orientation in the transfer region 15 of the conveyor 3 in succession, the paving stones 2 are first lifted by means of the lifting device 4 shown in FIGS. 1 to 5 such that they are spaced above the guide rollers 9 are located. The paving stones are, as seen in Figure 2, from the lower position in which they are tilted in the conveyor 3, pivoted upwards so that the side surfaces of the paving stones 2 are vertical or horizontal.

The lifting device 4 has five lifting units 54, which are independently pivotable about a common horizontal pivot axis 55. For the sake of clarity, only two of these lifting units 54 are shown in FIGS. 4 and 5. The pivot axis 55 runs parallel to the longitudinal direction of the transfer area 15.

The lifting units 54 in the embodiment shown each have four laterally spaced lifting elements in the form of pivoting levers 56. Three of these pivot levers 56 are L-shaped, while a pivot lever 56a is formed substantially S-shaped or Z-shaped. The end legs of the pivot lever 56 each have a support surface 57 for the paving stones 2, which is perpendicular to a support surface 58 of the adjacent leg.

All pivoting levers 56 of a lifting unit 54 are connected to each other by means of a tubular coupling element 59, so that the four pivoting levers 56 of a lifting unit 54 can only be pivoted together.

The pivoting of the lifting units 54 by means of actuating cylinder 60, which are shown in Figure 5. Each lifting unit 54 is associated with its own actuating cylinder 60, so that the lifting units 54 can be pivoted independently of one another. The actuating cylinders 60 have a piston rod 61, whose end is articulated on a lever arm 61 of the S-shaped pivot lever 56a. The opposite end of the actuating cylinder 60 is fixedly mounted on the support frame 67. If the piston rod 61 is in the extended position, the bearing surfaces 57, 58 of the lifting units 54 are in the lowered position, as can be seen from FIG.

In this lowered position, the L-shaped portions of the pivot lever 56 are in spaces between the guide rollers 9, as shown in Figure 2 can be seen. The pivot lever 56 are lowered so deep that the paving stones 2 can slide disability over the bearing surfaces 57, 58 to its predetermined end position in the transfer area 15. If the piston rod 61, however, retracted, the associated lifting unit 54 pivots high, causing the paving stone 2 arranged above it comes to rest on the support surfaces 57, 58 and is pivoted upward.

In order to prevent the paving stones 2 from tilting away from the bearing surfaces 57, 58 during lifting, each lifting unit 54 also has a retaining finger 62 which presses the paving stone 2 against the bearing surface 57 from the opposite side.

Are all lifting units 54, as shown in Figure 3, together with the paving stones 2 in the raised position, the gripper tongs 5 can be pivoted down so that the ends of the first

Gripping jaws 39 pass between the pivot lever 56 and engage under the paving stones 2. Subsequently, the paving stones 2 are clamped from above by means of the second gripping jaw 41, as described with reference to FIG. 9. Subsequently, the lifting units 54 are pivoted back down again, so that the paving stones 2 can be moved away from the gripping device 1 without hindrance in the horizontal direction from the transfer area 15 of the conveyor 3 along the rails 6.

Thus, the individual paving stones 2, which are serial, i. run into the transfer area 15 in succession, do not abut each other on the front side, the lifting units 54 also have stop elements 63. These stop elements 63 are L-shaped and have a straight leg 64 and an arcuate leg 65. The stop elements 63 are also designed as pivoting levers which are pivotable about the pivot axis 55. Furthermore, the stop elements 63 are coupled by means of the coupling elements 59 to the remaining part of the lifting units 54, so that the stop elements 63 are always pivoted together with the associated lifting units 54.

If a lifting unit 54 is pivoted up, as shown in FIG. 5, the arcuate leg 65 of the stop elements 63 moves into the region of the movement path of the paving stones 2, so that a subsequent paving stone 2 abuts the stop element 63 on the front side and thereby assumes the desired transfer position.

The feeding of the paving stones 2 into the transfer area 15 takes place in such a way that first a first paving stone 2 is introduced into the transfer area 15 until this paving stone 2 abuts against a stop of the foremost lifting unit 54. This attack can be monitored for example by suitable sensors. The foremost lifting unit 54 is swung up immediately thereafter, together with the paving stone 2 lying thereon and the stop element 63 lying behind in the conveying direction, as can be seen from FIGS. 2 and 5. Subsequently, the second paving stone 2 is introduced into the transfer area 15 until it abuts on the swung-up stop element 63. Now, this lifting unit 54 is also swung together with the paving stone 2 lying thereon and the stop element 63 lying behind in the conveying direction. This process is repeated until all the lifting units 54 of the transfer area 15 are occupied, as shown in FIG. As already described, the lifted paving stones 2 can now be grasped by means of the gripping device 1 and moved by moving the gripping device 1 to the desired paving stone delivery area.

During this transfer operation, the distance between the gripping units 8 and thus the distance between the paving stones 2 can be changed by means of the described distance changing device and / or the angle which the paving stones 2 have to the longitudinal direction of the gripping device 1 can be changed by means of the described angle adjustment device.

The paving stones 2 are appropriately moved in this conversion process by means of the gripping device 1 until the paving stones 2 triggered a stop, which is present in the paving stone delivery area or until the paving stones 2 held in the grippers 5 abut an already deposited paving stone row on the pallet , The gripper tongs 5 are then opened, so that the paving stones 2 can fall over a small amount on the pallet or the already deposited paving stone layer. If a paving stone layer on the pallet is fully occupied, then the storage table, on which the pallet is located, can be lowered by the height of a paving stone layer, so that a new paving stone layer can be laid.

In the illustrated embodiment, the paving stones 2 are so on the

Lifting units 54 that their narrow longitudinal sides are below or above. In this position, the paving stones 2 are also stored on the pallet. However, it is also readily possible for the paving stones 2 to be introduced into the transfer area 15 in such a way that their broad longitudinal sides on the lifting units 54 are at the bottom or at the top.

Furthermore, it may be expedient to support the stop elements 63 in such a way that they can be adjusted along the pivot axis 55. In this way, the position of the paving stones 2 on the lifting units 54 can be changed so that the paving stones 2 always rest centrally on the lifting units 54.

Claims (16)

1. A device for arranging paving stones (2) in a specific laying pattern on a pallet or other base, with a conveyor (3) for the serial transporting of the paving stones (2) to a transfer device comprising a gripping device (1) with a gripper holder (7 ) which is movable between a paving stone receiving area and a spaced paving stone delivery area, characterized in that the gripping device (1) comprises a plurality of gripping units (8) attached to the gripper holder (7), with each of which a paving stone (2) and - a position change device acting between the gripper holder (7) and the gripper units (8) with a distance changing device for changing the mutual spacing of the gripping units (8) and / or with an angle adjusting device for changing the angle between the gripping units (8) and the gripper holder (7), so that between the Paving stone receiving area and the paving stone delivery area the mutual positioning of the gripped paving stones (2) is changeable. 2. Apparatus according to claim 1, characterized in that the gripper holder (7) is designed in the form of a carriage or carriage which is movable or displaceable on rails (6) between the paving stone receiving area and the paving stone delivery area. 3. Apparatus according to claim 1 or 2, characterized in that the distance changing means at least one along the gripper holder (7) arranged guide rail (14) on which the gripping units (8) are slidably supported, and a sliding device for moving the gripping units (8). along the guide rail (14), wherein the sliding device with at least a part of the gripping units (8) is in operative connection. 4. The device according to claim 3, characterized in that the sliding device comprises sliding strips (22), which are hinged on one side to a gripping unit to be moved (8) and on the other hand on a common pivotable lever (23) at articulation points (25a, 25d) to the pivot axis (24) of the lever (23) are positioned differently. 5. Device according to one of the preceding claims, characterized in that the gripping units (8) about mutually parallel pivot axes (30) are pivotable and have lateral arms (37) on which actuating rods (36) of the angle adjustment at hinge points (38) are articulated , which are laterally offset to the pivot axes (30). 6. The device according to claim 5, characterized in that the Winkeiverstelleinrichtung comprises a splined shaft (19) and pivot lever (35) slidably mounted on the spline shaft (19), but rotatably supported and with the actuating rods (36) are hingedly connected. 7. The device according to claim 6, characterized in that the gripping units (8) on the at least one guide rail (14) by means of brackets (13) are slidably supported, the splined bearing (18) for rotatably supporting the spline shaft (19), wherein the Consoles (13) along the spline (19) are displaceable. 8. Device according to one of the preceding claims, characterized in that the gripping units (8) each comprise a gripping tongs (5) for clamping the paving stones (2) and an actuating cylinder (34) for opening and closing the gripping tongs (5). 9. The device according to claim 8, characterized in that the gripping tongs (5) by means of a single actuating cylinder (34) both a horizontal pivot axis (40) between a raised and a lowered position pivotally movable and between an open and a closed position are. 10. Apparatus according to claim 8 or 9, characterized in that the gripping tongs (5) have a first gripping jaws (39) and a second gripping jaws (41), wherein the first gripping jaws (39) is articulated, on retaining cheeks (33) is supported, while the second gripping jaw (41) is articulated on the first gripping jaw (39) and guided, wherein the actuating cylinder (34) on the one hand on the retaining cheeks (33) is supported and on the other hand on the second gripping jaws (41) engages. 11. Device according to one of the preceding claims, characterized in that the conveying device (3) comprises a transfer area (15) with a V-shaped guideway for the paving stones (2), wherein the guideway is formed by two rows of support elements which each other are arranged at an angle of 90 °. 12. The apparatus according to claim 11, characterized in that the support elements consist of guide rollers (66). 13. The apparatus of claim 11 or 12, characterized in that in the region of the transfer area (15) of the conveyor (3) a lifting device (4) for the paving stones (2) is arranged with the paving stones (2) in one of the Supporting elements of the conveyor (3) lifted position can be brought, in which they are gripped by the gripping units (8). 14. The apparatus according to claim 13, characterized in that the lifting device (4) has lifting elements which are insertable into intermediate spaces between the support elements of the conveyor (3). 15. The apparatus according to claim 14, characterized in that the lifting elements consist of pivot levers (56) which are pivotable about a horizontal axis (55) which is parallel to the longitudinal axis of the transfer region (15) of the conveyor (3). 16. The apparatus of claim 14 or 15, characterized in that the lifting device (4) comprises lifting elements which are coupled in movement with stop elements (63) which in the conveying space of the transfer region (15) of the conveyor (3) are movable to the stop position the paving stones (2) in the transfer area (15) set.