Gripper arrangement

Abstract

A gripper arrangement (10), in particular for transporting tools between a storage station and a machine tool, comprises at least two grippers (12, 14) and at least one clamping device (28) with a clamping element (30, 34) movable between a clamping position and a release position for clamping a tool or a cassette containing the tool (16) between at least one gripper (12, 14) and the clamping element (30, 34).

Description

[0001] The invention relates to a gripper arrangement, in particular for transporting tools between a storage station and a machine tool.

[0002] Machine tools, such as punching machines, are operated with various tools. Tools that are not currently in use are stored at the storage station and, when needed, transported from the storage station to the machine tool, particularly the punching machine, by a gripper assembly. For punching machines, it is known, for example, to combine the upper and lower dies of a punching tool in a cassette. For transport between the machine and the storage location, the cassette is picked up by a gripper assembly. In the gripper assembly, the cassette rests loosely on gripper arms. To prevent the cassette from hanging at too much of an angle in the gripper assembly, the gap dimensions between the gripper arms and the cassette are very small, for example, in the applicant's "ToolMaster" product. Consequently, all parts and assemblies involved in the gripping process must be manufactured and aligned with high precision.For example, the gripping tolerance for picking up a cassette from a die-cutting tool holder is only + / - 0.3mm.

[0003] The object of the present invention is therefore to provide a gripper arrangement with which a tool or a cassette containing a tool can be reliably gripped, but larger tolerances are achievable.

[0004] According to the invention, this problem is solved by a gripper arrangement, in particular for transporting tools between a storage station and a machine tool, with at least two grippers and at least one clamping device with a clamping element movable between a clamping position and a release position for clamping a tool or a cassette containing the tool between at least one gripper and the clamping element.

[0005] The clamping element allows the cassette or tool to be actively clamped and correctly aligned. The gripper itself no longer needs to be positioned relative to the cassette or tool with the previously required tolerance. Tolerances of up to + / - 1.8 mm are possible with the gripper arrangement according to the invention. The gripper arrangement according to the invention is more cost-effective than the previously used gripper arrangement because, due to the higher permissible tolerances, the parts and assemblies involved in the gripping process can be manufactured with greater tolerances. This results in more cost-effective production. Furthermore, the gripper arrangement according to the invention ensures high process reliability and the safe transport of tools or cassettes containing tools.

[0006] At least one gripper can have a horizontally oriented gripper section, and the clamping element can be vertically movable relative to the gripper section. Thus, a cassette or tool can be placed onto the horizontally oriented gripper section, or the gripper section can grip under the cassette or tool, and the cassette or tool can be clamped onto the horizontally oriented gripper section by the clamping element, or clamped between the clamping element and the gripper section. During the clamping process, the cassette or tool can also be aligned with respect to the gripper section.

[0007] Particular advantages arise when the clamping element can be pneumatically, hydraulically, or electrically driven. In particular, the clamping element can be driven by a linear actuator. If the clamping element is pneumatically or hydraulically driven, it can be designed to be particularly cost-effective. Specifically, a clamping device that is available on the market as a standard product can be used. It therefore does not need to be specially adapted to the gripper arrangement according to the invention.

[0008] If the clamping element can be moved against the restoring force of a spring element, an active drive for the clamping element may be unnecessary. Such a design can be implemented particularly cost-effectively.

[0009] The at least one clamping device can include a detector for recognizing whether the gripper assembly has picked up a tool or a cassette containing a tool. It can be provided that active clamping is only carried out if the detector has previously recognized that the gripper assembly has indeed picked up a tool or a tool cassette. The detector can, for example, be designed as a cylinder switch that is provided and arranged on a conventional pneumatic cylinder.

[0010] If the clamping element is L-shaped, linear pressure can be applied to the cassette or tool. In particular, the horizontally oriented section of an L-shaped clamping element can be pressed against the cassette or workpiece. Therefore, it may be sufficient to provide only one clamping element, which also prevents the cassette from tilting.

[0011] Alternatively, the gripping element can be cylindrical. This allows for the application of either a surface or point pressure from above onto the cassette or workpiece.

[0012] It is particularly preferred if two clamping elements are provided, especially two cylindrical clamping elements. A single clamping device can have two clamping elements. Alternatively, it is conceivable that two clamping devices, each with one clamping element, are provided. This configuration, in particular, allows clamping devices to be arranged on both sides of a gripper mechanism. If two clamping elements are provided, a cassette or tool that is held by the gripper arrangement can be aligned particularly well and clamped securely.

[0013] If, as mentioned above, the clamping elements, in particular clamping devices, are arranged on both sides of a gripper, they do not interfere with the gripper mechanism.

[0014] Controlling the grippers is simplified when the grippers are motion-coupled. This way, the movement or drive of one gripper automatically leads to the movement of the other gripper as well.

[0015] At least one of the grippers can have two gripping arms. This allows the gripper to have two support points for a cassette or tool, ensuring a secure hold.

[0016] The invention also includes a machine tool, in particular a punching machine, with a gripper arrangement according to the invention.

[0017] Further features and advantages of the invention will become apparent from the following detailed description of exemplary embodiments of the invention with reference to the figures in the drawing, which show essential details of the invention, as well as from the claims. The features shown therein are not necessarily to scale and are depicted in such a way that the inventive features are clearly visible. The various features can be implemented individually or in any combination in variants of the invention.

[0018] The schematic drawing shows exemplary embodiments of the invention in various stages of use, which are explained in more detail in the following description.

[0019] They show: Fig. 1 a first perspective view of a gripper arrangement according to the invention; Fig. 2 a second perspective view of the gripper arrangement according to the invention; and Fig. 3 a front view of the gripper arrangement according to the invention.

[0020] The Fig. Figure 1 shows a gripper arrangement 10 with a first gripper 12 and a second gripper 14. The grippers 12 and 14 are coupled and can be moved horizontally towards and away from each other. The grippers 12 and 14 hold a cassette 16 on which a punching tool 18, comprising an upper tool 20 and a lower tool 22, is mounted. The gripper arrangement 10 allows the cassette 16, together with the punching tool 18, to be moved between a storage station (not shown) and a machine tool and back.

[0021] The grippers 12, 14 each have horizontal sections 24, 26 with which they engage in corresponding receptacles of the cassette 16. This means that the cassette 16 rests with its sections on the horizontal sections 24, 26 of the grippers 12, 14. To fix and align the cassette 16 in this position, a clamping device 28 is provided, which has a clamping element 30. In the exemplary embodiment, the clamping element 30 is cylindrical. The clamping element 30 can be moved between a release position and the clamping position shown here. In the downward-shifted clamping position, the clamping element 30 clamps the cassette 16 firmly between the horizontal gripper sections 24, 26 and the clamping element 30.

[0022] When the gripper assembly 10, which can be mounted on a robot arm, is moved downwards with grippers 12, 14 open, and the clamping element 30 comes into contact with a cassette 16 and is possibly moved slightly upwards, a detector (not shown) can detect that the gripper assembly 10 has grasped a cassette 16, or alternatively, that a cassette 16 is present. Only when this is detected can corresponding pressure be applied to the clamping element 30 and it moved downwards to achieve the clamping effect. In the illustrated embodiment, the clamping element 30 is pneumatically actuated. Therefore, a pneumatic connection 32 is provided on the clamping device 28.

[0023] The Fig. Figure 2 shows that the gripper 14 has two gripper arms 14.1, 14.2, which are designed analogously. The horizontal section 26 is also clearly visible here.

[0024] The Fig.Figure 3 shows the removal of the two gripper arms 14.1 and 14.2. It is also evident that not only is the clamping element 30 present, but also a clamping element 34. The clamping elements 30 and 34 can be controlled together or individually. The clamping elements 30 and 34 are arranged on both sides of a gripper mechanism, so that they do not interfere with the gripper mechanism that allows the grippers 12 and 14 to move towards and away from each other.

Claims

[1] Gripper arrangement (10), in particular for transporting tools between a storage station and a machine tool, with at least two grippers (12, 14) and at least one clamping device (28) with a clamping element (30, 34) movable between a clamping position and a release position for clamping a tool or a cassette containing the tool (16) between at least one gripper (12, 14) and the clamping element (30, 34). [2] Gripper arrangement according to claim 1, characterized by , that at least one gripper (12, 14) has a horizontally oriented gripper section (24, 26) and the clamping element (30, 34) is movable vertically relative to the gripper section (24, 26). [3] Gripper arrangement according to one of the preceding claims, characterized by , that the clamping element (30, 34) can be pneumatically, hydraulically or electrically driven. [4] Gripper arrangement according to one of the preceding claims, characterized by, that the clamping element (30, 34) is movable against the restoring force of a spring element. [5] Gripper arrangement according to one of the preceding claims, characterized by , that at least one clamping device (28) has a detector for detecting whether the gripper arrangement (10) has received a tool or a cassette (16) containing a tool. [6] Gripper arrangement according to one of the preceding claims, characterized by that the clamping element is L-shaped. [7] Gripper arrangement according to one of the preceding claims, characterized by , that the clamping element (30, 34) is cylindrical in shape. [8] Gripper arrangement according to one of the preceding claims, characterized by , that two clamping elements (30, 34) are provided. [9] Gripper arrangement according to one of the preceding claims, characterized by , that the clamping elements (30, 34) are arranged on both sides of a gripper (12, 14). [10] Gripper arrangement according to one of the preceding claims, characterized by , that the grippers (12, 14) are motion-coupled. [11] Gripper arrangement according to one of the preceding claims, characterized by , that one of the grippers (14) has two gripper arms (14.1, 14.2). [12] Machine tool, in particular punching machine, with a gripper arrangement (10) according to one of the preceding claims.

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