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EP-4585361-B1 - CLAMPING DEVICE

EP4585361B1EP 4585361 B1EP4585361 B1EP 4585361B1EP-4585361-B1

Inventors

  • Maurer, Eckhard
  • DANNECKER, Patrick

Dates

Publication Date
20260513
Application Date
20210913

Claims (6)

  1. Clamping device (1) for holding a workpiece (3) to be machined by a machine tool (2), comprising: - a housing (4), - a support surface (6') which is formed by the housing (4), - at least one clamping jaw (7) axially movably mounted in the housing (4) and a counter-stop (10) formed by the housing (4), between which the workpiece (3) is clamped, or at least two clamping jaws (7, 8, 9) axially movably mounted in the housing (4), between which the workpiece (3) is clamped, and - a drive device (11) by means of which the movable clamping jaws (7, 8, 9) are controllably movable, and by means of which a holding force transmitted from the clamping jaws (7, 8, 9) to the workpiece (3) or to a clamping bolt (3') coupled with the workpiece (3) is generated during the clamping process, and - an electromechanical and/or inductive interface (12, 13) provided on the housing (4), which is connected to the drive device (11) and/or an evaluation device (11') inductively and/or by means of electrical lines (16), and - a robot arm (14) which communicates with the interface (12, 13) in such a way that electrical data signals and/or electrical energy can be transmitted alternately and bidirectionally between the interface (12, 13) of the housing (4) and an electromechanical and/or inductive interface (12', 13') of the robot arm (14), characterised in that, the drive device (11) is electrically operated and a free end of the robot arm (14), as soon as the robot arm (14) has placed the workpiece (3) on the support surface (6'), is rotatable in such a way that the electromechanical and inductive interfaces (12', 13') provided on the free end (15) of the robot arm (14) are aligned flush with the electromechanical and inductive interfaces (12, 13) of the housing (4).
  2. Clamping device (1) according to claim 1, characterised in that, the evaluation device (11') is electrically or inductively connected to at least one proximity sensor (32), in that the position of the workpiece (3) is measured by the respective proximity sensor (32) with respect to a reference axis (4') of the housing (4) and/or with respect to a support surface (6) assigned to the housing (4), and in that the measurement result determined by the respective proximity sensor (32) is forwarded to the evaluation device (11') in the form of electrical data signals.
  3. Clamping device (1) according to claim 1 or 2, characterised in that, the robot arm (14) is mounted on a chassis (17), in that a control device (18) is assigned to the chassis (17), by means of which the chassis (17) and/or the movements of the robot arm (14) are automatically moved, and in that a program for checking the clamping situation of the workpiece (3) on the clamping device (1) is run by the control device (18).
  4. Clamping device (1) according to claim 3, characterised in that, the rotational speed of the drive device (11) and/or the stroke path of the clamping jaws (7, 8, 9) is generated by the control device (18), in that measurement results are generated by this query, which are used by the control device (18) to enable the machine tool (2).
  5. Clamping device (1) according to any one of the preceding claims, characterised in that, the electromechanical interface (12) comprises one or more pins (19, 19'...) or sockets (20, 20'...), and in that corresponding sockets (21, 21'...) or pins (22, 22'...) are provided on the free ends (15) of the robot arm (14), which are mechanically and electrically coupled in pairs.
  6. Clamping device (1) according to any one of the preceding claims, characterised in that, the inductive interface (13) comprises an interface surface (23), in that an inductively operated transmitting and/or receiving device (24) is assigned to the interface surface (23), and in that the robot arm (14) comprises an interface surface (25), to which a transmitting and/or receiving device (26) is assigned for communication with the transmitting and/or receiving device (26) of the interface (25) of the clamping device (1).

Description

The invention relates to a clamping device for holding a workpiece to be machined by a machine tool according to the preamble of claim 1. Such a clamping device is already available from the DE 10 2012 014 617 B3 Previously known. Further state of the art is the EP 3 391 991 A1 and the EP 3 653 333 B1 to be taken. Such clamping devices can be used as chucks, vises, or zero-point clamping systems. For all such clamping devices, the centered arrangement of the workpiece relative to a reference plane or axis, for example, the axis of symmetry of the housing, is of crucial technical importance, as the workpiece should be machined by a machine tool with the lowest possible error tolerance. This requires knowing the exact position of the workpiece relative to a reference plane or axis and achieving this clamping position with repeatable accuracy when replacing an identical workpiece. A disadvantage is that currently, the workpieces to be processed must be changed manually by the operator. Each workpiece must therefore be clamped in place and, after the machining process, removed from the clamping device in order to insert another workpiece. Furthermore, a disadvantage of known clamping devices has been found to be that the workpiece position changes during insertion and/or during the machining process due to the prevailing centrifugal forces, for example, from the chuck or the rotation of a pallet or the workpiece table of a machine tool. When inserting the workpiece, particles in the form of chips or other contaminants can be present between the workpiece and the clamping jaw, or between the workpiece and a contact surface on the housing onto which the workpiece is to be placed flat. This can then cause a change in the workpiece's position. Therefore, before the machining process begins, the machine tool must first check whether the workpiece is correctly inserted in the clamping device. However, since the workpiece is inserted manually and known clamping devices often use hydraulic or mechanical drive systems to move the clamping jaws, checking the position of the inserted workpiece is time-consuming, and the operating personnel require corresponding technical knowledge to perform this check. It is therefore an object of the invention to further develop both an automated insertion and a clamping device of the type mentioned above, by which an automated position check of the inserted workpiece can be carried out and that, when the test result is available, either the start of the machining process is automatically initiated or a check of the position of the workpiece in the clamping device is carried out. This problem is solved according to the invention by the features of the characterizing part of claim 1. Further advantageous embodiments of the invention are set out in the dependent claims. The fact that the housing has an electromechanical and/or inductive interface that is inductively and/or electrically connected to the drive unit and/or an evaluation unit ensures that the If an interface for an external robot arm is accessible and communicates with it in such a way that electrical data signals and/or electrical energy can be transmitted alternately and bidirectionally between the interface and the robot arm, an automated query regarding the clamping position of the workpiece in the clamping device is carried out before the machining process by the machine tool begins. Advantageously, the robot arm used for automated verification of the workpiece's clamping position in the clamping device can be mounted on a chassis, allowing it to move freely within an assembly hall and thus access multiple machine tools and query their clamping parameters. It is also conceivable to attach the robot arm to a ceiling, crane, or similar structure and move it within a specific area where the corresponding machine tools are located. A control unit integrated into the robot arm's chassis can advantageously control both the robot arm's movement and the workpiece's clamping position in the clamping device. Only after the control unit has verified the correct clamping position does it issue a corresponding electrical command signal, enabling the machine tool. Consequently, after the workpiece is inserted into the clamping device, its clamping position can be automatically verified, and the machining process can be initiated if the measurement results are positive. To establish electrical data signal transmission between the clamping device and the robot arm, the housing is provided with pins or slots for mechanical and electrical coupling. Optionally, an inductive interface in the form of a contact surface can be provided. Corresponding mechanical or inductive interfaces are provided at the free end of the robot arm, enabling the robot arm to be mechanically and electrically connected to the housing's mechanical interface during the testing period. A contactless data transmission occurs between the robot arm and the housing's i