Gripper device, system, and method for unloading a work machine

Abstract

The invention relates to a gripper device (24) for gripping workpieces (12). The gripper device (24) has: a support structure (30); a robot arm interface (34) for securing the gripper device (24) to a robot arm (22); a first gripper (38) for gripping a first workpiece (12); a second gripper (40) for gripping a second workpiece (12); and a third gripper (42) for gripping a third workpiece (12). The first gripper (38), the second gripper (40), and the third gripper (42) are detachably secured to the support structure (30).

Description

[0001]

[0002] Gripper device, system and method for unloading a machine tool

[0003] The invention relates to a gripper device, a system and a method for unloading a machine tool.

[0004] Machine tools are typically used to manufacture or machine workpieces. After machining or manufacturing, the workpieces can be removed from the machine tool using a gripper device and placed on a storage area. Removing the workpieces from the machine tool can also be referred to as unloading the machine tool. The storage area may be an area where the workpieces are stacked.

[0005] The invention aims to provide a gripper device, a system, and a method, each with improved properties, in particular enabling an increase in productivity.

[0006] The invention solves this problem by providing a gripper device with the features of claim 1, a system with the features of claim 11, and a method with the features of claim 12. Advantageous embodiments and further developments of the invention are set forth in the dependent claims.

[0007] A gripper device according to the invention is designed for gripping workpieces. The gripper device comprises a support structure, a robot arm interface, a first gripper, a second gripper, and a third gripper. The robot arm interface is designed for attaching the gripper device to a robot arm. The first gripper is designed for gripping a first workpiece. The second gripper is designed for gripping a second workpiece. The third gripper is designed for gripping a third workpiece. The robot arm interface is arranged, in particular directly, on the support structure. The first gripper is detachably attached to the support structure. The second gripper is detachably attached to the support structure. The third gripper is detachably attached to the support structure. Advantageously, by providing three grippers, three workpieces can be gripped simultaneously.This allows a machine tool, preferably a sheet metal working machine or a laser cutting machine, to be unloaded more quickly, thus reducing downtime. As a result, the machine tool can be ready for use again sooner and process or produce further workpieces, thereby increasing its productivity.

[0008] Another advantage of the gripper device is that a defective gripper can be replaced easily and without much effort. This can reduce the maintenance required for the gripper device.

[0009] Another aspect of the gripper device is that the support structure to which the grippers are attached, along with the robot arm interface, allows for quick mounting and replacement of the gripper device on a robot arm. This enables rapid adaptation to changing workpieces that, for example, require a different gripping principle. In particular, this allows the gripper device to be quickly and easily replaced with another gripper device. For example, a gripper device attached to the robot arm for unloading a machine tool might be equipped with suction grippers. A change in the workpieces to be produced by the machine tool might necessitate the use of magnetic grippers for unloading.The grippers of the gripper unit can each be designed as suction grippers, and the grippers of the other gripper unit can each be designed as magnetic grippers. Thanks to the robot arm interface, switching between the gripper unit and the other gripper unit is quick and easy.

[0010] The gripper device can also be called a robot gripper.

[0011] Each workpiece can be a cut sheet of metal or a cut plate. Each workpiece can be cut from a sheet of material, in particular sheet metal under a plate, preferably using a laser beam. The first, second, and third workpieces can be identical.

[0012] The width and / or length of each workpiece can be more than five times, in particular ten times, its thickness. Each workpiece can have a thickness ranging from 0.1 mm (millimeters) to 10 cm (centimeters), in particular from 0.2 mm to 5 cm.

[0013] Gripping can be understood as the holding of a workpiece. During gripping, a positive or non-positive connection can be established between the gripper that has grasped the workpiece and the gripped workpiece. When a workpiece is gripped, the robot arm can perform a movement without the gripped workpiece unintentionally detaching from the gripper.

[0014] The supporting structure can also be referred to as the base body or main body. The supporting structure can be designed as a housing that encloses an interior space. The supporting structure can be formed from flat plates that are connected to each other, preferably welded.

[0015] The robot arm interface enables secure and repeatable attachment of the gripper device to the robot arm. The robot arm interface can be designed to attach the gripper device to the robot arm using a bayonet fitting and / or a screw connection. The robot arm interface can have a number of connections for transmitting control signals and / or power. The robot arm interface can allow the gripper device to be attached and the connections to be made simultaneously. In other words, the robot arm interface allows the gripper device to be attached to the robot arm by establishing a mechanical connection and simultaneously connected to the sensor and / or pneumatic system.

[0016] The robot arm can be described as an industrial robot. The robot arm can be configured as a 6-axis industrial robot.

[0017] The robot arm can include a manipulator and a control system. The control system can also be referred to as control electronics or automation electronics. The control system can include an electronic processing unit, in particular a computer and / or a microcontroller.

[0018] The controller can be configured to control the manipulator and send control commands to the gripper attached to the manipulator. The robot arm interface can be configured to be attached to the manipulator. The manipulator can have an interface corresponding to the robot arm interface for attaching the gripper.

[0019] Each gripper can be designed as a magnetic gripper. It is also conceivable that each gripper could be designed as a pincer gripper. It is also conceivable that each gripper could be designed as a jaw gripper.

[0020] Each gripper can be attached to the support structure by means of a bayonet fitting and / or a screw connection.

[0021] The first gripper, the second gripper, and the third gripper can be attached to different sides of the support structure.

[0022] Each gripper can extend along a longitudinal axis away from the supporting structure, particularly if the gripper is attached to the supporting structure. The longitudinal axis of the first gripper can be oriented orthogonally to the longitudinal axis of the second gripper and orthogonally to the longitudinal axis of the third gripper. The longitudinal axis of the second gripper can also be oriented orthogonally to the longitudinal axis of the third gripper.

[0023] In a further development of the gripper device, the first gripper has a contact surface for contacting the first workpiece. The second gripper has a contact surface for contacting the second workpiece. The third gripper has a contact surface for contacting the third workpiece. The contact surface of the first gripper is oriented orthogonally to the contact surface of the second gripper. The contact surface of the second gripper is oriented orthogonally to the contact surface of the third gripper. This ensures that the first workpiece, gripped by the first gripper, cannot obstruct the gripping of the second workpiece by the second gripper, nor the gripping of the third workpiece by the third gripper.In general terms, this prevents already gripped workpieces from hindering or preventing the gripping of further workpieces.

[0024] Another aspect can be that this allows a gripped workpiece to be placed in a narrow storage area without being hindered or prevented by the other workpieces.

[0025] The contact surface of the first gripper can be a flat contact surface. The contact surface of the second gripper can be a flat contact surface. The contact surface of the third gripper can be a flat contact surface. Each contact surface can be designed to form a tactile contact with a workpiece for gripping the workpiece. In particular, each gripped workpiece can make tactile contact with the contact surface of the gripper that is gripping the workpiece.

[0026] In a further development of the gripper device, the gripper device includes a medium distributor. The medium distributor is designed to supply the first, second, and third grippers with a medium. The support structure has an interior space. The medium distributor is located within this interior space. This prevents accidental damage to the medium distributor. Furthermore, hoses and / or cables leading to or from the medium distributor are protected from accidental damage by the support structure.

[0027] The operating medium distributor can have one, in particular a single, inlet for supplying the operating medium to the distributor. The operating medium distributor can have a number of outlets for dispensing the operating medium. The number of outlets can correspond to the number of attackers of the gripper device. Each gripper can be connected to an outlet.

[0028] The operating medium can be, for example, vacuum, compressed air, hydraulic oil, or electrical energy. Vacuum can be understood as a gaseous medium that has a pressure lower than the pressure of the surrounding environment provided by the gripping device.

[0029] In other words, the operating medium distributor can provide each gripper with an electrical supply, a pressurized supply, and / or a vacuum supply. By attaching the gripper assembly to the robot arm via the robot arm interface, the operating medium distributor can simultaneously be connected to an operating medium source. The operating medium source can be configured to supply the operating medium. In particular, the operating medium source can supply or apply electrical energy, compressed air, and / or vacuum to the operating medium distributor.

[0030] In a further development of the gripper device, the gripper device has a first interface for the detachable attachment of the first gripper to the support structure. The gripper device has a second interface for the detachable attachment of the second gripper to the support structure. The gripper device has a third interface for the detachable attachment of the third gripper to the support structure.

[0031] Each interface can be located on the support structure. Each interface can enable the secure and repeatable attachment of a gripper to the support structure. Each interface can be designed to attach a gripper to the support structure using a bayonet fitting and / or a screw connection. Each interface can have a number of connections for transmitting control signals and / or power. Each interface can allow for the attachment of a gripper and the simultaneous connection of the ports. In other words, each interface allows a gripper to be attached to the support structure by establishing a mechanical connection and simultaneously connects the gripper via signaling and / or pneumatics. In particular, a gripper attached to the support structure via an interface can be supplied with the operating medium.

[0032] The first interface, the second interface and the third interface can be located on different sides of the supporting structure.

[0033] In a further development of the gripper device, the first gripper has a distance module and a gripping module. The second gripper has a distance module and a gripping module. The third gripper has a distance module and a gripping module. Each distance module has an interior space in which a control device for controlling the application of an operating medium to the gripping module is located. This protects the control device from unintentional damage.

[0034] Another aspect of the distance module is that it increases the distance between the gripping module, which is mounted on the distance module, and the support structure and other grippers, thereby enabling the placement of a workpiece gripped by the gripping module into a box or container. In particular, this allows the gripping module to be inserted into the box or container to place a gripped workpiece without the support structure or other grippers obstructing or preventing this insertion.

[0035] The control unit can also be referred to as control electronics or control unit. The control unit can include an electronic processing unit, in particular a microcontroller. However, it is also conceivable that the control unit is a valve. Specifically, the control unit can control and / or regulate the application of an operating medium to the gripping module, which causes it to grip a workpiece.

[0036] In other words, each gripper can have a control device located in the gripper's distance module.

[0037] Each control device can cause the gripper to transition between a release state and a gripping state. If a workpiece is positioned on a gripper, particularly on a contact surface of the gripper, and the control device transitions the gripper into the gripping state, the workpiece may be gripped by the gripper after the transition. In the gripped state, the workpiece cannot be released from the gripper. When the control device transitions the gripper into the release state, the workpiece can be released from the gripper.

[0038] The distance module of the first gripper can be positioned between the gripping module of the first gripper and the support structure. The distance module of the second gripper can be positioned between the gripping module of the second gripper and the support structure. The distance module of the third gripper can be positioned between the gripping module of the third gripper and the support structure.

[0039] Each gripper module can have a number of gripping elements. If the gripper module is a suction gripper, the gripping element can be a suction cup. If the gripper module is a magnetic gripper, the gripping element can be a magnet. If the gripper module is a tong gripper, the gripping element can be tongs. If the gripper module is a jaw gripper, the gripping element can be a gripping jaw.

[0040] In a further development of the gripper device, the first, second, and third grippers are identical. This allows for a reduction in the manufacturing costs of the gripper device due to economies of scale.

[0041] In a further development of the gripper device, the first gripper is designed as a suction gripper. The second gripper is designed as a suction gripper. The third gripper is designed as a suction gripper. Suction grippers can grip workpieces cut from a sheet of material particularly securely and reliably.

[0042] Each suction gripper can be subjected to negative pressure for gripping a workpiece. The negative pressure allows the workpiece to be pressed against the suction gripper. Each control unit can be configured to apply negative pressure to the gripping module, and in particular to the number of gripping elements within the gripping module, depending on a control signal from the controller.

[0043] In a further development of the gripper device, the supporting structure has a cube-like shape. This allows the gripper device to be designed to be particularly compact.

[0044] In a further development of the gripper device, the device features a fourth gripper for gripping a fourth workpiece. This fourth gripper is detachably attached to the support structure. The gripper device also features a fifth gripper for gripping a fifth workpiece. This fifth gripper is also detachably attached to the support structure. This allows for an increase in the number of workpieces that can be gripped simultaneously, thereby further increasing productivity.

[0045] The description given above for the first gripper, second gripper, or third gripper can apply accordingly to the fourth and fifth gripper. In particular, all grippers of the gripper device can be of the same design.

[0046] The first gripper, the second gripper, the third gripper, the fourth gripper and the fifth gripper can be attached to different sides of the support structure.

[0047] In a further development of the gripper device, the fourth gripper has a contact surface for contacting the fourth workpiece. The fifth gripper also has a contact surface for contacting the fifth workpiece. The contact surface of the fourth gripper is oriented orthogonally to the contact surface of the fifth gripper.

[0048] The previously given description of the contact surface of the first gripper, the contact surface of the second gripper, or the contact surface of the third gripper can apply accordingly to the contact surface of the fourth gripper and the contact surface of the fifth gripper.

[0049] The contact surface of the fourth gripper can be aligned parallel to the contact surface of the first gripper. The contact surface of the fifth gripper can be aligned parallel to the contact surface of the second gripper.

[0050] A system according to the invention is designed for gripping a plurality of workpieces. The system comprises a gripper device as described above and the robot arm. The gripper device is attached to the robot arm via the robot arm interface. The description of the robot arm given above can apply to the robot arm of the system.

[0051] A method according to the invention serves to unload a machine tool using a previously described system. The method comprises: gripping a plurality, for example 3, 4 or 5, of workpieces arranged on the machine tool by means of the grippers of the gripper device, wherein at least 50% of the grippers of the gripper device are gripping a workpiece; transporting the workpieces to a storage area by moving the robot arm; and placing the workpieces onto the storage area by releasing the workpieces.

[0052] The previously given description of the machine tool can also apply to the machine tool of the process.

[0053] Unloading can also be described as clearing or sorting the machine tool.

[0054] The workpieces arranged on the machine tool can be workpieces that have been machined or manufactured by the machine tool.

[0055] The gripping of the majority of workpieces can be achieved by gripping the workpieces one after the other, consecutively, or sequentially.

[0056] The phrase "a workpiece is gripped by at least 50% of the grippers of the gripper device" can be understood to mean that a workpiece is gripped by at least 50% of the total number of grippers of the gripper device.

[0057] The robot arm controller can initiate, cause, or control the movement of the robot arm. In particular, the robot arm controller can issue control commands that cause the robot arm to move.

[0058] The storage area can be an area where the workpieces are to be placed. The storage area can be defined by a box or container.

[0059] Releasing can involve letting go of the workpieces from the gripper device. Releasing multiple workpieces can be achieved by releasing them one after the other, consecutively, or sequentially. In a further development of the method, gripping includes changing the orientation of the gripper device after gripping one workpiece to grip another. This change of orientation can be performed quickly, allowing the machine tool to be unloaded rapidly.

[0060] Changing the orientation of the gripper device can be achieved by rotating it. This rotation can be a 90° turn. The gripper device can also be rotated around a pivot point that coincides with the center point of the supporting structure.

[0061] In other words, gripping multiple workpieces can be achieved by first grasping one workpiece with a gripper from the gripper device. The orientation of the gripper device can then be changed by rotating it 90°. Subsequently, another workpiece can be gripped with another gripper from the gripper device. This process can continue until all grippers in the gripper device have grasped a workpiece or no further workpieces are available for gripping.

[0062] In a further development of the process, after the majority of workpieces have been gripped, each gripper in the gripper device grips one workpiece at a time. This allows the gripper device to be optimally utilized, enabling a large number of workpieces to be transported to the storage area simultaneously.

[0063] In a further development of the process, the placement includes: changing the orientation of the gripper device after placing one workpiece in order to place another workpiece. This change of orientation can be performed quickly, which is why the workpieces can be placed quickly.

[0064] The description for changing the orientation of the gripper device when placing workpieces can be applied analogously to changing the orientation when gripping workpieces. In particular, rotating the gripper device by 90° can be applied analogously to changing the orientation when placing workpieces.

[0065] The placement of the majority of workpieces can be achieved by releasing a workpiece gripped by a gripper of the gripper device. The orientation of the gripper device can then be changed by rotating it 90°. Subsequently, another workpiece gripped by a different gripper of the gripper device can be released. This process can continue until all workpieces transported to the placement area by the gripper device have been released.

[0066] Other aspects of the gripper device can include:

[0067] By changing the TCP (Tool Center Point), the robot gripper can pick up and place parts, especially workpieces, sequentially. In sheet metal processing, the robot gripper can efficiently perform conventional single-part handling.

[0068] A central support structure in the form of a cube can be attached to an industrial robot. One surface can house the interface to the robot, while the other surfaces contain interfaces for manipulators. By changing the TCP (Control Point Combination), each manipulator can pick up a part in succession. The gripper can then be moved to the placement area, and the parts can be deposited one after the other.

[0069] The advantages can be that no active degrees of freedom are required in the gripper and that the interference contour is optimal when immersing in boxes and containers.

[0070] The basis for guiding the gripper can be a robotic system with the appropriate degrees of freedom, typically a 6-axis industrial robot. This can be equipped with a gripper interface that ensures the mechanical connection, electrical signal connection, and pneumatic supply.

[0071] Components of the gripping system can include:

[0072] Gripper mount and support structure: The gripper mount, which supports the central support structure, can be attached to the gripper interface. Ideally, this structure should be cube-shaped and house the electrical and pneumatic components.

[0073] Manipulator interfaces: The remaining five available surfaces of the supporting structure can be equipped with manipulator interfaces. These can provide power and signal supply for the manipulators.

[0074] Manipulators: The manipulators can consist of a manipulator extension and a gripping element. The extension can house the support structure as well as the power and signal distribution. The gripping elements, which can vary depending on the application (e.g., vacuum grippers, magnets, or pincer grippers), are located at the end.

[0075] How it works:

[0076] Handling process:

[0077] Suitable manipulators can be equipped for the handling process. The robot can partially orient itself to the TCP (Tool Center Point) of manipulator 1 so that it can be picked up. Then, the TCP of manipulator 2 can be oriented to part 2, followed by parts 3 through 5. Due to the compact arrangement around the robot's TCP, it can traverse the TCPs of the manipulators with minimal movements.

[0078] Filing process:

[0079] To place the part, the robot can move to placement position 1 with manipulator 1 and the gripped part, and then place the part down. It can then move to placement position 2 with manipulator 2, and so on. In principle, different manipulators can be pre-configured for a process to effectively address specific parts.

[0080] Alternatively, the invention could be implemented using any non-cubic body with more or fewer surfaces than a cube has.

[0081] Further advantages and advantageous embodiments of the invention can be seen from the figures, their description, and the claims. All features disclosed in the figures, the description, and the claims can be essential to the invention, both individually and in any combination. The figures show:

[0082] Fig. 1 shows a schematic representation of a system with a machine tool, a system and a storage area.

[0083] Fig. 2 shows a schematic representation of the system with a robot arm and a gripper device,

[0084] Fig. 3 shows a schematic representation of the gripper device,

[0085] Fig. 4 is a schematic representation of the gripper device with one workpiece gripped by the gripper device, Fig. 5 is a schematic representation of the gripper device with two workpieces gripped by the gripper device, and

[0086] Fig. 6 shows a schematic representation of the gripper device with five workpieces gripped by the gripper device.

[0087] Fig. 1 shows a device 10 for cutting workpieces 12 from a sheet of material. The sheet of material can also be referred to as a sheet or plate. The sheet of material is made of a metal, for example, iron or aluminum. The width and / or length of the sheet of material can be more than five times, in particular ten times, its thickness. For example, the thickness of the sheet of material can be in the range of 0.1 mm to 10 cm, in particular 0.2 mm to 5 cm.

[0088] The system 10 has a machine tool 14, which cuts the workpieces 12 from the material sheet. The machine tool 14 is a laser cutting machine. The workpieces 12 are cut from the material sheet by means of a laser beam from the machine tool 14. After the workpieces 12 have been cut, they lie on the machine tool 14.

[0089] The workpieces 12 are to be placed in a box 16. The box 16 defines a storage area 18, which is equivalent to the interior of the box 16.

[0090] To remove the workpieces 12 from the machine tool 14 and place them in the box 16, the system 10 has a system 20. By removing the workpieces 12 from the machine tool 14, the machine tool 14 is unloaded and can process another, subsequent sheet of material.

[0091] The system 20 is designed to grasp a plurality of workpieces 12 simultaneously, transport them to the storage area 18 and place them in the storage area 18.

[0092] System 20 consists of a robot arm 22 and a gripper device 24. System 20 is shown in more detail in Fig. 2.

[0093] The robot arm 22 has a manipulator 26 and a controller 28. The controller 28 is configured to send control commands that cause a desired movement of the manipulator 26. Additionally, the controller 28 can send a control command to the gripper device 24, causing it to grip a workpiece. The gripper device 24 has a support structure 30. The support structure 30 has a cube-like shape. In other words, the support structure 30 has six sides. Each side is formed from a flat surface of the support structure 30. Each surface is oriented orthogonally to the surfaces adjacent to it. The areas of the surfaces are equal. The support structure 30 is designed as a housing that encloses an interior space 32.

[0094] The gripper device 24 has a robot arm interface 34. The robot arm interface 34 is located directly on the support structure 30. The robot arm interface 34 serves to attach the gripper device 24 to the robot arm 22. The gripper device 24 is attached to the robot arm 22 by means of the robot arm interface 34.

[0095] The control unit 28 can be connected to the gripper device 24 via signal technology if the gripper device 24 is attached to the robot arm 22 by means of the robot arm interface 34.

[0096] The system 10 has a working medium source 36 for supplying working media. The working medium source 36 can, for example, be a number of connections from which a working medium can be drawn. The working medium source 36 can, for example, supply electrical current, compressed air and / or vacuum.

[0097] When the gripper device 24 is attached to the robot arm 22, the gripper device 24 is connected to the operating medium source 36 via the robot arm interface 34, so that at least one operating medium from the operating medium source 36 can be supplied to the gripper device 24 via the robot arm interface 34.

[0098] In the illustrated embodiment, the operating medium source 36 provides electrical current and vacuum. Therefore, the gripper device 24 is supplied with electrical current and vacuum via the robot arm interface 34.

[0099] Fig. 3 shows the gripper device 24. The gripper device 24 has a first gripper 38, a second gripper 40, a third gripper 42, a fourth gripper 44, and a fifth gripper 46. The grippers 38, 40, 42, 44, and 46 are identical. Each gripper 38, 40, 42, 44, and 46 is designed to grip a workpiece 12. Therefore, the gripper device 24 can grip five workpieces 12 simultaneously.

[0100] The gripper device 24 has a first interface 48 for attaching the first gripper 38 to the support structure 30, a second interface 50 for attaching the second gripper 40 to the support structure 30, a third interface 52 for attaching the third gripper 42 to the support structure 30, a fourth interface 54 for attaching the fourth gripper 44 to the support structure 30, and a fifth interface 56 for attaching the fifth gripper 46 to the support structure 30.

[0101] Each interface 48, 50, 52, 54, 56 is located directly on the support structure 30. Each interface 48, 50, 52, 54, 56 is located on one side of the support structure 30, with the interfaces 48, 50, 52, 54, 56 being located on different sides of the support structure 30. In other words, no more than one interface 48, 50, 52, 54, 56 is located on any one side of the support structure 30.

[0102] The grippers 38, 40, 42, 44, 46 are detachably attached to the support structure 30 via interfaces 48, 50, 52, 54, 56. Each interface 48, 50, 52, 54, 56 is configured to supply the gripper 38, 40, 42, 44, 46 attached to that interface with an operating medium. In particular, each gripper 38, 40, 42, 44, 46 is supplied with a control signal and vacuum via the interface 48, 50, 52, 54, 56 to which it is attached.

[0103] The gripper device 24 has a power medium distributor 58, see Fig. 1. The power medium distributor 58 serves to supply each gripper 38, 40, 42, 44, 46 with the power medium. The power medium distributor 58 is arranged in the interior 32 of the support structure 30. The power medium distributor 58 is designed to provide the electrical current, which is supplied to the gripper device 24 via the robot arm interface 34, to each gripper 38, 40, 42, 44, 46, and in particular to distribute it among the grippers 38, 40, 42, 44, 46. In addition, the operating medium distributor 58 is designed to provide the negative pressure, which is supplied to the gripper device 24 via the robot arm interface 34, to each gripper 38, 40, 42, 44, 46, in particular to distribute it to the grippers 38, 40, 42, 44, 46.

[0104] Each gripper 38, 40, 42, 44, 46 has a distance module 60 and a gripping module 62, see Fig. 3. Each distance module 60 serves to increase the distance or clearance between the gripping module 62 and the support structure 30. This allows the gripping module 62 of a gripper 38, 40, 42, 44, 46 to plunge a gripped workpiece 12 into the box 16 without the other grippers obstructing or preventing this plunge into the box 16.

[0105] Each gripper 38, 40, 42, 44, 46 has a control unit 64, see Fig. 1. Each distance module 60 has an interior space in which the control unit 64 is arranged. Each control unit 64 serves to control the application of negative pressure to the gripper module 62. Each control unit 64 can be configured to receive a control signal from the controller 28 that initiates a release or gripping action by means of the gripper. Depending on the control signal from the controller 28, each control unit 64 can cause the release or gripping of a workpiece. In particular, depending on the control signal from the controller 28, each control unit 64 can control the application of negative pressure to the gripper module 62.

[0106] Each gripping module 62 has a plurality of gripping elements 66, see Fig. 3. Each gripping element 66 is a suction cup. Each gripping element 66 can be subjected to negative pressure for suctioning a workpiece 12 against the gripping module 62. The gripping elements 66 of a gripping module 62 define a contact surface 68 for contacting a workpiece 12. Each contact surface 68 is a flat surface. However, it is also conceivable that the contact surfaces 68 are adapted to a shape of the workpieces 12 and therefore deviate from a flat surface.

[0107] The grippers 38, 40, 42, 44, 46 are attached to the support structure 30 such that the contact surface 68 of the first gripper 38 is orthogonal to the contact surface 68 of the second gripper 40, the contact surface 68 of the first gripper 38 is orthogonal to the contact surface 68 of the third gripper 42, the contact surface 68 of the second gripper 40 is orthogonal to the contact surface 68 of the third gripper 42, the contact surface 68 of the fourth gripper 44 is orthogonal to the contact surface 68 of the fifth gripper 46, the contact surface 68 of the fourth gripper 44 is parallel to the contact surface 68 of the first gripper 38 and the contact surface 68 of the fifth gripper 46 is parallel to the contact surface 68 of the second gripper 40.

[0108] Figures 4 to 6 show the unloading process of the machine tool 14. After the workpieces 12 have been cut out, the machine tool 14 is unloaded by means of the system 20 and the workpieces 12 are placed in the box 16. For this purpose, the control unit 28 activates the manipulator 26, which positions the gripper device 24 relative to a first workpiece 12 such that the first workpiece 12 makes contact with the first gripper 38 at its contact surface 68. Subsequently, the control unit 28 sends a control command to the control device 64 of the first gripper 38, which initiates the gripping of the first workpiece 12 with the first gripper 38. The control device 64 of the first gripper 38 causes the gripping elements 66 of the first gripper 38 to be subjected to negative pressure, thereby drawing the first workpiece 12 against the first gripper 38. As a result, the first workpiece 12 is gripped by the first gripper 38. Fig.Figure 4 shows that the first workpiece 12 is gripped by the first gripper 38.

[0109] The controller 28 controls the manipulator 26 such that it changes the orientation of the gripper device 24 to grip a second workpiece 12. The orientation of the gripper device 24 is changed by rotating it by 90°. Simultaneously or subsequently, the gripper device 24 is positioned relative to the second workpiece 12 so that the second workpiece 12 makes contact with the second gripper 40 at its contact surface 68. The controller 28 then sends a control command to the control unit 64 of the second gripper 40, which initiates the gripping of the second workpiece 12 by the second gripper 40. The control unit 64 of the second gripper 40 causes the gripping elements 66 of the second gripper 40 to be subjected to negative pressure, thereby drawing the second workpiece 12 against the second gripper 40. The second workpiece 12 is thus gripped by the second gripper 40. Fig.Figure 5 shows that the second workpiece 12 is gripped by the second gripper 40.

[0110] This process continues until at least 50% of the grippers 38, 40, 42, 44, 46 have gripped a workpiece 12. In the illustrated embodiment, the process continues until each gripper 38, 40, 42, 44, 46 has gripped a workpiece 12, see Fig. 6. In other words, a plurality of workpieces 12 are gripped successively by means of the gripper device 24.

[0111] The control unit 28 controls the manipulator 26 in such a way that the manipulator 26 performs a movement by which the workpieces 12 are transported to the box 16.

[0112] The control unit 28 controls the gripper device 24 for placing the gripped workpieces 12 into the box 16 by releasing the gripped workpieces 12. The gripped workpieces are released one after the other.

[0113] In detail, the controller 28 controls the manipulator 26 such that the first gripper 38 enters the box 16. The controller 28 then sends a release command to the control unit 64 of the first gripper 38. The control unit 64 terminates the suction applied to the first gripper 38. As a result, the first workpiece 12 is no longer held against the first gripper 38. This releases the first workpiece 12 from the first gripper 38. The controller 28 then controls the manipulator 26 such that the orientation of the gripper device 24 is changed for the placement of the second workpiece 12. The first gripper 38 is removed from the box 16 without the first workpiece 12, and the second gripper 40 enters the box 16 together with the second workpiece 12. The controller 28 then sends a release command to the control unit 64 of the second gripper 40.The control device 64 terminates the application of suction to the second gripper 40. As a result, the second workpiece 12 is no longer drawn against the second gripper 40. This releases the second workpiece 12 from the second gripper 40. This process continues until all gripped workpieces 12 have been placed in the box 16.

Claims

Patent claims 1. Gripper device (24) for gripping workpieces (12), wherein the gripper device (24) comprises: a supporting structure (30), a robot arm interface (34) for attaching the gripper device (24) to a robot arm (22), a first gripper (38) for gripping a first workpiece (12), a second gripper (40) for gripping a second workpiece (12), and a third gripper (42) for gripping a third workpiece (12), wherein the robot arm interface (34) is arranged on the support structure (30), wherein the first gripper (38), the second gripper (40) and the third gripper (42) are detachably attached to the support structure (30).

2. Gripper device (24) according to claim 1, wherein the first gripper (38) has a contact surface (68) for contacting the first workpiece (12), wherein the second gripper (40) has a contact surface (68) for contacting the second workpiece (12), wherein the third gripper (42) has a contact surface (68) for contacting the third workpiece (12), wherein the contact surface (68) of the first gripper (38) is aligned orthogonally to the contact surface (68) of the second gripper (40) and orthogonally to the contact surface (68) of the third gripper (42), wherein the contact surface (68) of the second gripper (40) is aligned orthogonally to the contact surface (68) of the third gripper (42).

3. Gripper device (24) according to one of the preceding claims, wherein the gripper device (24) has a power medium distributor (58), wherein the power medium distributor (58) is configured to provide a power medium to the first gripper (38), the second gripper (40) and the third gripper (42), wherein the supporting structure (30) has an interior space (32), wherein the operating medium distributor (58) is arranged in the interior (32) of the support structure (30).

4. Gripper device (24) according to one of the preceding claims, wherein the gripper device (24) has a first interface (48) for the detachable attachment of the first gripper (38) to the support structure (30), wherein the gripper device (24) has a second interface (50) for the detachable attachment of the second gripper (40) to the support structure (30), wherein the gripper device (24) has a third interface (52) for the detachable attachment of the third gripper (42) to the support structure (30).

5. Gripper device (24) according to one of the preceding claims, wherein the first gripper (38) has a distance module (60) and a gripping module (62), wherein the second gripper (40) has a distance module (60) and a gripping module (62), wherein the third gripper (42) has a distance module (60) and a gripping module (62), wherein each distance module (60) has an interior space in which a control device (64) for controlling the application of an operating medium to the gripping module (62) is arranged.

6. Gripper device (24) according to one of the preceding claims, wherein the first gripper (38), the second gripper (40) and the third gripper (42) are identical in design.

7. Gripper device (24) according to one of the preceding claims, wherein the first gripper (38) is designed as a suction gripper, wherein the second gripper (40) is designed as a suction gripper, wherein the third gripper (42) is designed as a suction gripper.

8. Gripper device (24) according to one of the preceding claims, wherein the supporting structure (30) has a cube-like shape.

9. Gripper device (24) according to one of the preceding claims, wherein the gripper device (24) has a fourth gripper (44) for gripping a fourth workpiece (12) and a fifth gripper (46) for gripping a fifth workpiece (12). wherein the fourth gripper (44) and the fifth gripper (46) are detachably attached to the support structure (30).

10. Gripper device (24) according to claim 9, wherein the fourth gripper (44) has a contact surface (68) for contacting the fourth workpiece (12), wherein the fifth gripper (46) has a contact surface (68) for contacting the fifth workpiece (12), wherein the contact surface (68) of the fourth gripper (44) is aligned orthogonally to the contact surface (68) of the fifth gripper (46).

11. System (20) for gripping a plurality of workpieces (12), wherein the system (20) comprises: a gripper device (24) according to one of the preceding claims, and the robot arm (22), wherein the gripper device (24) is attached to the robot arm (22) via the robot arm interface (34).

12. Method for unloading a machine tool (14) using a system (20) according to claim 11, wherein the method comprises: Gripping a plurality of workpieces (12) arranged on the machine tool (14) by means of the grippers (38, 40, 42) of the gripper device (24), wherein at least 50% of the grippers (38, 40, 42) of the gripper device (24) grip a workpiece (12), Transporting the workpieces (12) to a storage area (18) by a movement of the robot arm (22), Placing the workpieces (12) onto the storage area (18) by releasing the workpieces (12).

13. Method according to claim 12, wherein gripping includes: changing the orientation of the gripper device (24) after gripping one of the workpieces (12) for gripping another workpiece (12).

14. Method according to claim 12 or 13, wherein, after the majority of workpieces (12) have been gripped by all grippers (38, 40, 42) of the gripper device (24), one workpiece (12) is gripped.

5. Method according to any one of the preceding claims 12 to 14, the placing includes: changing the orientation of the gripper device (24) after placing one of the workpieces (12) for the placement of another workpiece (12). - 22 -

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