DEVICE AND METHOD FOR TURNING SHEETS

Description

[0001] The invention relates to a sheet metal processing plant with a conveyor for conveying a workpiece and a turning unit for turning the workpiece, as well as a method for turning sheets for a sheet metal processing plant.

[0002] Turning devices for turning workpieces are generally known. DE102004057105 B3 describes a turning device for turning workpieces between processing stations, in particular for press stations. It proposes two workpiece carriers, which are coupled to a drive device and each have a holding surface. With the aid of the drive device, the workpiece carriers are designed to be pivotable from a starting position to a transfer position, thus pivoting the workpiece from one workpiece carrier to the other. Furthermore, a transfer device is designed to deposit or pick up the workpieces on or from the turning device.

[0003] The device known from DE102004057105 B3 has the disadvantage that a separate manipulator must be provided in order to convey the workpiece from a press station to the turning unit and that it is also moved between the workpiece carriers during turning.

[0004] Furthermore, the current state of the art also involves turning sheets of metal with the help of additional conveyors and multi-axis robots.

[0005] CN107915029 A, on which the preamble of independent patent claims 1 and 8 is based, discloses a turning unit, wherein the turning unit comprises a manipulator, which manipulator is designed to lift the underside of the workpiece from the receiving surface, to carry out a turning operation of the workpiece and to place the upper side of the workpiece onto the receiving surface of the conveyor, wherein the complete turning unit is rotated by 180° for turning.

[0006] In addition, it is known to design the conveyor device in a sheet metal processing plant so that it can rotate around the conveying direction, which can, however, lead to incorrect workpiece alignment and damage.

[0007] The object of the present invention was to overcome the disadvantages of the prior art and to provide an improved device or an improved method for turning sheets, in which a turning process can be carried out using simple means and with little space.

[0008] This object is achieved by a device and a method according to the claims.

[0009] According to the invention, a sheet metal processing system is designed with a turning unit. The sheet metal processing system comprises: a conveying means, which defines a receiving surface for a workpiece and a conveying direction in a conveying plane, and is designed to convey one of the workpieces, which workpiece has a bottom and a top; a turning unit, which turning unit is designed to turn the workpiece received on the receiving surface from the bottom to the top, wherein it is further provided that the turning unit comprises a manipulator, which manipulator is designed to lift the underside of the workpiece from the receiving surface, to carry out a turning operation of the workpiece and to place the upper side of the workpiece onto the receiving surface of the conveying means.

[0010] This inventive design has the advantage that a workpiece is turned on the conveyor with simple means in a precise, gentle, space-saving and, above all, short time manner, in order to then feed the workpiece back into a process of the sheet metal processing system, thus enabling short cycle times.

[0011] An additional advantage is that operating costs can be saved due to the simple design of the turning unit.

[0012] Furthermore, due to the inventive design of the turning unit, its danger zone is made as small as possible, thereby ensuring a higher safety factor.

[0013] For the sake of completeness, it should be mentioned that the mentioned top and bottom sides are the surface of the sheet currently being picked up on the conveyor with regard to a subsequent turning process and that this surface is turned again from a bottom side to a top side of the workpiece during a further turning process.

[0014] Furthermore, it can be provided that at least components of the conveyor are designed to be movable in such a way that an access opening for the manipulator can be formed in the conveyor plane. This measure allows areas or additional devices of the turning unit, or even a storage unit, to be made quickly and space-savingly accessible to the manipulator.

[0015] According to a further development, the manipulator can comprise a gripping device designed to grip the workpiece at the top with a gripping surface. Gripping at the top has the advantage that the required gripping forces can be optimally distributed across the workpiece to avoid damage and similar undesirable effects.

[0016] It can also be advantageous if a part of the manipulator or a gripping device is designed to be movable or telescopic along an axis. This allows for even better adaptability to the workpiece geometry. Furthermore, this measure can make the placement or picking up of the workpiece more reliable.

[0017] It may be advantageous if the manipulator includes a gripping device designed to grip the workpiece at two opposite edges. This allows the gripping device to be particularly easily adapted to different workpiece dimensions.

[0018] For a better understanding, it should be mentioned that the term "edge-side" refers to a flat area in the peripheral edge area of the workpiece, which is formed on the top or bottom side of the workpiece and, depending on the orientation of the manipulator, can be aligned, e.g., parallel to the conveying direction or orthogonal to the conveying direction.

[0019] Furthermore, the gripping device can be provided with at least one turning head, which is designed to be pivotable by at least 180°. This allows the gripping device to pivot with the workpiece, enabling a rapid turning process in the smallest possible space.

[0020] It can be advantageous if the manipulator is designed to pivot about a pivot axis that is parallel to the conveying direction. This allows the lifting, turning, and depositing of the workpiece to be carried out around a single axis.

[0021] It can also be advantageous if the manipulator is designed to pivot about an axis that is parallel to the conveying plane and orthogonal to the conveying direction. This offers the advantage of enabling lifting, turning, and setting down about an axis, but also of allowing the component to be rotated about an axis orthogonal to the conveying direction, if necessary.

[0022] Furthermore, the manipulator comprises a first gripping device and a second gripping device, which are designed to transfer the workpiece from the first gripping device to the second gripping device during the turning process. This configuration makes it possible to turn the workpiece reliably and easily by gripping the workpiece flatly on the top and bottom sides, respectively, by the first and second gripping devices.

[0023] Furthermore, a method for turning sheets for a sheet metal processing plant is provided, comprising the following steps: Providing a sheet metal processing system, providing a conveyor, which conveyor defines a receiving surface for a workpiece and a conveying direction in a conveying plane and is designed to convey the workpiece, which workpiece has a bottom side and a top side, providing a workpiece on the receiving surface of the conveyor, providing a turning unit, which turning unit is designed to turn the workpiece received on the receiving surface from the bottom side to the top side, wherein the turning unit comprises a manipulator which lifts the bottom side of the workpiece from the receiving surface, carries out a turning process of the workpiece and places the top side of the workpiece onto the receiving surface of the conveyor.

[0024] The method according to the invention makes it possible to quickly and easily turn sheets that are placed on a conveyor in a sheet metal processing plant in order to enable short cycle times and save installation space.

[0025] Furthermore, it can be advantageous to provide at least one storage unit positioned below the conveyor level of the conveyor. This offers the advantage that sheets can be deposited or temporarily stored by the turning unit after the processing steps, or even removed from it for the first time before the processes. Otherwise, damaged or defective workpieces can also be deposited there. Furthermore, the storage unit can also serve as a storage area for parts of the manipulator or the turning unit.

[0026] Furthermore, it can be provided that an access opening for the manipulator is formed in the conveyor level, and at least components of the conveyor are displaced. This measure allows areas or additional devices of the turning unit, or even a storage area, to be made quickly and space-savingly accessible to the manipulator.

[0027] It can also be advantageous if the workpiece is prepared using the manipulator, whereby the workpiece is lifted from the storage area and placed on the receiving surface of the conveyor. This has the advantage of eliminating the need for an additional conveyor device that initially feeds the sheets to the sheet metal processing system.

[0028] It can also be advantageous if the manipulator includes a gripping device with a gripping surface, and the workpiece is gripped at the top with the gripping surface. Gripping at the top has the advantage that the required gripping forces can be optimally distributed across the workpiece, preventing damage and similar undesirable effects.

[0029] Furthermore, the manipulator can be provided with a gripping device, and the workpiece is gripped by the gripping device at two opposite edges. This measure makes it possible to grip workpieces of different geometries as easily as possible with the same gripping device.

[0030] Furthermore, it can be advantageous if the gripping device comprises at least one turning head that can be pivoted at least 180°, and the gripping device with the workpiece is at least partially rotated around a turning axis during the turning process. This measure allows for a rapid turning process in the smallest possible space.

[0031] According to a further development, it is possible for the manipulator to further comprise means by which the holding force of the gripping device is at least reduced during the turning process, and for the workpiece to slide off the gripping device when placed on the receiving surface of the conveyor when the holding force is reduced. This allows the workpiece to slide toward the receiving surface while the turning process is taking place. This can lead to additional time savings.

[0032] In the case of a suction or vacuum gripper, these means can include, for example, a compressed air control or vacuum control, and in the case of a magnetic gripper, a control of the magnetic field, or even pneumatic control in the case of a permanent magnet. Alternatively, the holding force can also be deactivated, which would allow for simplified control.

[0033] Furthermore, it is provided that the manipulator has a first gripping device and a second

[0034] Gripping device, wherein the underside of the workpiece is lifted from the receiving surface by means of the first gripping device and a first partial step of the turning process is carried out, the workpiece is transferred from the first gripping device to the second gripping device and is accepted by the latter, a second partial step of the turning process is carried out and the top side of the workpiece is placed onto the receiving surface of the conveyor by means of the second gripping device. By means of this configuration, it is possible to turn the workpiece in a simple and reliable manner, for example by the first or second gripping devices being able to grip the workpiece flatly on the top or bottom.

[0035] It can also be advantageous if parts of the manipulator or gripping device are designed to be movable relative to one another along an axis. This allows for even better adaptability to the workpiece geometry. Furthermore, this measure can make the placement or picking up of the workpiece more reliable.

[0036] The gripping devices may comprise grippers known from the prior art, e.g. magnetic grippers or suction or vacuum grippers.

[0037] Furthermore, it can also be provided that the gripping devices comprise pincer grippers, which can be advantageous when gripping at the ends of the workpiece.

[0038] The sheet metal processing system can comprise various systems known from the prior art, e.g. a punching device, a bending press, a laser processing system and others.

[0039] For a better understanding of the invention, it is explained in more detail using the following figures.

[0040] They show in a highly simplified, schematic representation: Fig. 1 shows an embodiment of a sheet metal processing plant with a conveyor and a turning unit in an oblique view; Fig. 2 shows a plan view of the conveyor with a variant of a turning unit; Fig. 3 shows a plan view of another embodiment of a turning unit; Fig. 4A to D show the embodiment of the turning unit according to Fig. 3 in a simplified representation, in side view; Fig. 5 shows a further possible embodiment of the turning unit, in plan view; Figs. 6A to D show a further embodiment of a turning unit in side view; Figs. 7A to D show a further possible embodiment of a turning unit in side view;

[0041] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied analogously to the new position in the event of a change in position.

[0042] The term "in particular" is understood below to mean that it may refer to a possible more specific embodiment or more detailed specification of an object or a method step, but does not necessarily have to represent a mandatory, preferred embodiment of the same or a mandatory procedure.

[0043] Furthermore, it should be noted that the Figures 1 to 5 , as well as Fig. 7 illustrated embodiments of the turning units 9 or manipulators 10 do not fall under the wording of the independent claims, since they do not comprise the first gripping device and second gripping device according to the wording of the claims, but these figures in their entirety are considered to be facilitating the understanding of the invention.

[0044] Fig. 1shows an embodiment of a sheet metal processing system 1 with a conveyor 2 and a turning unit 9 in an oblique view. The conveyor 2 defines a conveying plane 3 and a conveying direction 4, along which a workpiece 5 can be conveyed from or to a process of the sheet metal processing system 1. The workpiece 5 has an upper side 7 and a lower side 6. The lower side 6 of the workpiece 5 rests on the receiving surface 8 of the conveyor 2. The turning unit 9 has a manipulator 10, which is designed to lift the lower side 6 of the workpiece 5 from the receiving surface 8, to carry out a turning process of the workpiece 5 and to place the upper side 7 of the workpiece 5 onto the receiving surface 8 of the conveyor 2.

[0045] The embodiment of the manipulator 10 of the turning unit 9 in Fig.1, which does not comprise the first and second gripping devices according to the wording of the claims, shows a possible embodiment of the manipulator 10 with a gripping device 12 which grips the workpiece 5 at the edges at two opposite workpiece ends 13. The manipulator 10 is designed to be pivotable about an axis 17. The gripping device 12 comprises a turning head 15 which can be pivoted at least by 180° about a turning axis 16 by means of a turning drive 41. The gripping device 12 can further comprise means 34, as indicated by dashed lines, which can reduce or deactivate a holding force of the gripping device 12 during the turning process in order to allow the workpiece 5 to slide off the gripping device 12 when it is placed on the receiving surface 8 of the conveyor 2.For this embodiment, the manipulator 10 can be designed telescopically, or can also be movable in a plane parallel to the conveying plane 3 in order to enable sliding onto the receiving surface 8.

[0046] However, sliding onto the receiving surface 8 can also be effected by slowly opening the gripping device 12 in the direction of the receiving surface 8, for example if it is a pincer gripper.

[0047] The Fig.1 However, the manipulator 10 shown or the gripping device 12 can also be designed such that they have movable or telescopic parts along the conveying direction 4, so that a distance 35 of the gripping device 12 for receiving a workpiece 5 can be adapted to different lengths 36 of different workpieces 5. Furthermore, changing the distance 35 can enable the workpiece 5 to slide off the gripping device 12.

[0048] The sheet metal processing system can comprise various systems known from the state of the art, e.g. a punching device, a bending press or even a laser processing system and others.

[0049] The Fig. 2 to 4 The embodiments of the manipulator shown also do not include the first and second gripping devices covered by the wording of the claims.

[0050] Fig. 2shows a possible embodiment of the conveyor 2 with a variant of a turning unit 9 in plan view, which does not show the first and second gripping devices covered by the wording of the claims. The manipulator 10 is designed to be pivotable about a pivot axis 17 and comprises a gripping device 12 with a gripping surface 14 and a turning head 15. At least components of the conveyor 2 are designed to be displaceable, so that an access opening 20 for the manipulator 10 can be formed in the conveying plane 3. The conveyor 2 can, for example, comprise individual conveyor elements 24, which are designed to be movable with the aid of a conveyor drive 32 and are moved, for example, into a conveyor storage unit 31 to form the access opening 20.

[0051] Below this access opening 20, a storage 11 is formed, which can, for example, receive or provide a workpiece 5. Otherwise, the storage 11 can also serve to receive a gripping device 12, for example, to be able to change the gripping device 12 for different geometries of the workpiece 5, if this is designed to be coupled to the manipulator 10. A storage 11 can also be arranged next to the conveyor 2, as in Fig. 2 indicated by dashed lines. Furthermore, the storage unit 11 can also be designed to be movable. Using the storage unit, a workpiece 5 can, for example, be picked up for the first time by the manipulator 10 and fed to a process of the sheet metal processing system 1 via the conveyor 2. It should be noted that the storage unit 11 is designed independently of the design of the conveyor and the turning unit and can also be used in the following figures.

[0052] Furthermore, a drive device 37 is shown, which may include a pivot drive for the manipulator 10. Furthermore, the drive device 37 may include means for moving the manipulator 10 along a horizontal direction 40 or the conveying direction 4.

[0053] Fig. 3shows a possible embodiment of a turning unit 9 with a manipulator 10 in plan view, which does not comprise a first and second gripping device according to the wording of the claims, which can be pivoted by means of a drive device 37 about a pivot axis 17 that is parallel with respect to the conveying direction 4. Furthermore, the turning unit 9 has a storage area 19 arranged parallel with respect to the conveying plane 3 of the conveying means 2, which can be moved between a first operating position 21 and a second operating position 22. This configuration serves to ensure that the manipulator 10 can place the workpiece 5 on the storage area 19 in the first operating position 21 during the turning process and can pick it up again in the second operating position 22.

[0054] The movement between the operating positions can be carried out, for example, by means of an actuator 38, as in Fig.3 shown.

[0055] In the illustrated embodiment, the support 19 can move linearly into the aforementioned operating positions 21, 22. Alternatively, it would also be possible to configure it to move in an arc, for example, in order to rotate the workpiece 5 by an angle, e.g., by 180°, in addition to the turning process in a plane parallel to the conveying plane 3.

[0056] In this embodiment, the manipulator 10, which does not comprise the first and second gripping devices according to the wording of the claims, has individual gripping arms 25 that can pivot together about the pivot axis 17. Alternatively, the gripping arms 25 can also be pivoted individually about the axis 17.

[0057] It should be mentioned here that the storage 19 and the manipulator 10 must be designed in such a way that they do not block each other when turning the workpiece 5 and moving it into the operating positions 21, 22.

[0058] Fig. 4A to 4Dshow the embodiment of the turning unit 9 according to Fig. 3 simplified representation in side view, as well as a turning process and also do not include the first and second gripping device according to the wording of the claims. The tray 19 is located in Fig. 4A in the first operating position 21, while the manipulator 10 lifts the underside 6 of the workpiece 5 from the receiving surface 8 of the conveyor 2 by means of the gripping arms 25. The manipulator 10 pivots about the pivot axis 17 in Fig. 4B the workpiece 5 with the upper side 7 onto the support 19 and remains below it. Meanwhile, the access opening 20 is formed in the conveyor 2. According to Fig. 4C the storage unit 19 moves into the second operating position 22, the manipulator pivots back over the axis 17, grasps the workpiece 5 on its underside 6 through the access opening 20 and lifts it from the storage unit 19.

[0059] The manipulator then conveys the workpiece 5 through the access opening 20 over the conveying level 3 of the conveyor 2 and places the workpiece 5 with its upper side 7 onto the receiving surface 8 of the conveyor 2 as shown in Fig. 4D It should be noted here that at least components of the conveyor 2 are moved again accordingly, so that the access opening 20 is closed again in order to be able to receive the workpiece 5.

[0060] Alternatively, the sequence described here can of course also be reversed, as indicated by the reference numerals in parentheses, so that the storage unit 19 is located in its first operating position 21 below the access opening 20, the manipulator lifts the workpiece 5 with its underside 6 from the receiving surface 8, places it through the access opening 20 onto the storage unit 19, pivots it about the pivot axis 17, the storage unit 19 is moved into its second operating position 22 and the manipulator 10 grasps the workpiece 5 at its underside 6, pivots it about the pivot axis 17 and then places it with its upper side 7 onto the receiving surface 8 of the conveyor means 2.

[0061] In an embodiment not shown, it is also possible to arrange the shelf by means of a suspension or the like above the conveying plane of the conveyor, which would eliminate the need for an access opening.

[0062] To compensate for any height difference between the storage area 19 and the conveyor level 3 and the resulting inclination of the gripper arms 25 of the manipulator 10, the manipulator 10 or the storage area 19, or parts thereof, can be designed to be height-adjustable. Alternatively, the distance between the pivot axis 17 of the manipulator 10 and the conveyor can be designed to be correspondingly large, so that the angle of inclination of the gripper arms 25 relative to the storage area 19 is as small as possible.

[0063] Fig. 5 shows another embodiment of the turning unit 9 and the manipulator 10 in plan view, which does not include the turning unit covered by the wording of the claims. In this case, the support 19 can also include an intermediate position 39, so that it can move between the operating positions 21, 22 when the manipulator 10 is pivoted out of its pivot radius to avoid a collision.

[0064] Furthermore, in Fig. 5an axis 18 is indicated, which is arranged orthogonally with respect to the conveying direction 4 and parallel with respect to the conveying plane 3. Alternatively, the manipulator 10' and the support 19' can be arranged such that the manipulator 10' pivots the workpiece 5 about this axis 18 during the turning process, as indicated by dashed lines. Furthermore, the support 19' can also be movable not linearly, but, for example, along a radius.

[0065] In the Fig. 5 a further and possibly independent embodiment of the turning unit 9 is shown, which does not fall under the wording of the claims, wherein again the same reference numerals or component designations are used for the same parts as in the previous Fig.3 and 4A to 4D To avoid unnecessary repetition, reference is made to the detailed description in the preceding figures.

[0066] Regardless of the design of the turning unit 9 in Fig. 5 Other designs of a manipulator 10 can also be designed to be pivotable about an axis 18 arranged orthogonally to the conveying direction 4 and parallel to the conveying plane 3.

[0067] Fig. 6A to 6Dshow an embodiment of a turning unit 9 according to the invention in a side view in a simplified representation, wherein the manipulator 10 comprises a first gripping device 26 and a second gripping device 27. The first gripping device 26 is designed to lift the underside 6 of the workpiece 5 from the receiving surface 8 of the conveyor 2, carry out a first sub-step of the turning process, transfer the workpiece 5 to the second gripping device 27, which receives the workpiece 5 from the first gripping device 26, grips it at the underside 6, carries out a second sub-step of the turning process and places the workpiece 5 by means of its upper side 7 onto the receiving surface 8 of the conveyor 2. The sub-steps of the turning process described here can, for example, each comprise a swivel angle of 90°, as shown, but also two different swivel angles, which complement each other to form a supplementary angle. For example,the first swivel angle is 135° and the second 45°.

[0068] For the sake of completeness, it should be mentioned that a holding force of the first gripping device is deactivated during transfer to the second gripping device as soon as the workpiece has been transferred and the first gripping device must be moved or pivoted in such a way that the pivoting range of the second gripping device is not blocked.

[0069] In this embodiment, it would also be possible to reverse the functions of the two gripping devices 26, 27, as indicated by the reference numerals in brackets.

[0070] Furthermore, it is possible to design the two gripping devices differently, so that one gripping device grips the workpiece on the top or bottom side and the other gripping device grips the workpiece, for example, on the edge.

[0071] Fig. 7A to 7Dshow a side view of a variant embodiment of a turning unit 9, which does not comprise the first and second gripping devices covered by the wording of the claims, wherein the manipulator 10 comprises a gripping device 12 which is designed to grip the workpiece 5 on the upper side 7 with a gripping surface 14. Furthermore, the manipulator 10 comprises means 34 which can reduce or deactivate the holding force 23 of the gripping device 12 during the turning process. The mentioned means 34 can meet different technical requirements depending on the design of the gripping device 12. In the case of a suction or vacuum gripper, these means can comprise, for example, a compressed air control or negative pressure control, and in the case of a magnetic gripper, a control of the magnetic field, or when using a permanent magnet, also pneumatically, as already mentioned at the beginning.

[0072] Furthermore, the gripping device 12 comprises a turning head 15, which is designed to be pivotable by at least 180°. Furthermore, a turning drive 41 is indicated by dashed lines, by means of which the turning head 15 pivots into the required angular position.

[0073] In the embodiment shown, the manipulator 10 is movable along the horizontal direction 40, so that it can slide the workpiece 5 off the gripping surface 14 during the turning process. Alternatively, the manipulator 10 can also comprise a telescopic arm 33, as indicated by dashed lines. Likewise, the gripping device 12 could also be designed to be movable accordingly, as in Fig. 7C indicated.

[0074] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size. Reference symbol list 1 Sheet metal processing plant 31 Funding storage 2 Funding 32 Conveyor drive 3 funding level 33 Telescopic arm 4 Conveying direction 34 Medium 5 workpiece 35 Distance 6 bottom 36 length 7 Top 37 drive device 8 Recording area 38 Actuator 9 Turning unit 39 Intermediate position 10 manipulator 40 Horizontal direction 11 memory 41 Reversing drive 12 gripping device 13 Workpiece ends 14 Gripping surface 15 Turning head 16 Turning axis 17 Swivel axis 18 axis 19 filing 20 Access opening 21 first operating position 22 second operating position 23 Holding force 24 Conveying element 25 gripper arm 26 first gripping device 27 second gripping device 28 first gripping section 29 second gripping section 30 axis of rotation

Claims

1. A sheet metal processing plant (1) comprising - a conveying means (2), said conveying means (2) defining a receiving surface (8) for a workpiece (5) and a conveying direction (4) in a conveying plane (3) and being embodied for conveying the workpiece (5), said workpiece (5) having a bottom side (6) and a top side (7), - a turning unit (9), said turning unit (9) being embodied for turning the workpiece (5) received on the receiving surface (8) from the bottom side (6) to the top side (7), - wherein the turning unit (9) comprises a manipulator (10), said manipulator (10) being embodied to lift the bottom side (6) of the workpiece (5) off the receiving surface (8), to perform a turning operation of the workpiece (5) and to place the top side (7) of the workpiece (5) on the receiving surface (8) of the conveying means (2), characterized in that the manipulator (10) comprises a first gripping device (26) and a second gripping device (27) embodied to transfer the workpiece (5) from the first gripping device (26) to the second gripping device (27) during the turning operation, wherein the second gripping device (27) is embodied to place the top side (7) of the workpiece (5) on the receiving surface (8) of the conveying means (2).

2. The sheet metal processing plant (1) according to claim 1, characterized in that at least parts of the conveying means (2) are embodied to be displaceable such that in the conveying plane (3), an access opening (20) for the manipulator (10) can be formed.

3. The sheet metal processing plant (1) according to claim 1 or 2, characterized in that the manipulator (10) comprises a gripping device (12), said gripping device (12) being embodied to grip the workpiece (5) on the top side (7) with a gripping surface (14).

4. The sheet metal processing plant (1) according to one of the preceding claims, characterized in that the manipulator (10) comprises a gripping device (12) which is embodied to grip the workpiece (5) on the edges of two opposite workpiece ends (13).

5. The sheet metal processing plant (1) according to claim 3 or 4, characterized in that the gripping device (12) comprises at least one turning head (15), said turning head (15) being embodied to be pivotable at least by 180°.

6. The sheet metal processing plant (1) according to one of the preceding claims, characterized in that the manipulator (10) is embodied being pivotable about a pivot axis (17), said pivot axis (17) being arranged in parallel with respect to the conveying direction (4).

7. The sheet metal processing plant (1) according to one of the preceding claims, characterized in that the manipulator (10) is embodied being pivotable about an axis (18), said axis (18) being arranged in parallel with respect to the conveying plane (3) and orthogonally with respect to the conveying direction (4).

8. A method for turning metal sheets for a sheet metal processing plant (1), in particular for a sheet metal processing plant (1) according to claim 1 to 7, comprising the following steps - providing a sheet metal processing plant (1), - providing a conveying means (2), said conveying means (2) defining a receiving surface (8) for a workpiece (5) and a conveying direction (4) in a conveying plane (3) and being embodied for conveying a workpiece (5), said workpiece (5) having a bottom side (6) and a top side (7), - providing a workpiece (5) on the receiving surface (8) of the conveying means (2), - providing a turning unit (9), said turning unit (9) being embodied to turn the workpiece (5) received on the receiving surface (8) from the bottom side (6) to the top side (7), - wherein the turning unit (9) comprises a manipulator (10) which manipulator (10) lifts the bottom side (6) of the workpiece (5) off the receiving surface (8), carries out a turning operation of the workpiece (5) and places the top side (7) of the workpiece (5) on the receiving surface (8) of the conveying means (2), characterized in that the manipulator (10) comprises a first gripping device (26) and a second gripping device (27), wherein by means of the first gripping device (26), the bottom side (6) of the workpiece (5) is lifted off the receiving surface (8) and a first partial step of the turning operation is performed, the workpiece (5) is transferred from the first gripping device (26) to the second gripping device (27) and received by it, a second partial step of the turning operation is performed and the top side (7) of the workpiece (5) is placed on the receiving surface (8) of the conveying means (2) by means of the second gripping device (27).

9. The method according to claim 8, characterized in that a storage (11) is provided, which is positioned below the conveying plane (3) of the conveying means (2).

10. The method according to claim 8 or 9, characterized in that in the conveying means (2), an access opening (20) for the manipulator (10) is formed in the conveying plane (3), and, in this regard, at least parts of the conveying means (2) are displaced.

11. The method according to one of claims 8 to 10, characterized in that providing the workpiece (5) is carried out by means of the manipulator (10), wherein the workpiece (5) is lifted off the storage (11) and is placed on the receiving surface (8) of the conveying means (2) by means of the manipulator (10).

12. The method according to one of claims 8 to 11, characterized in that the manipulator (10) comprises a gripping device (12) with a gripping surface (14) and the workpiece (5) is gripped on the top side (7) with the gripping surface (14).

13. The method according to one of claims 8 to 11, characterized in that the manipulator (10) comprises a gripping device (12), and the workpiece (5) is gripped on the edges of two opposite workpiece ends (13) by the gripping device (12).

14. The method according to claim 12 or 13, characterized in that the gripping device (12) comprises at least one turning head (15), which is embodied to be pivotable by at least 180° and the gripping device (12) is turned at least partially about a turning axis (16) with the workpiece (5) in the turning operation.

15. The method according to one of claims 8 to 14, characterized in that the manipulator (10) further comprises means (34) by which a holding force (23) of the gripping device (12) is at least reduced during the turning operation and that when the holding force (23) is reduced, the workpiece (5) slides off the gripping device (12) when it is placed on the receiving surface (8) of the conveying means (2).