Clamp device

Abstract

To provide a clamp device which makes not only automated mounting but also detection of position of a mounted workpiece possible.SOLUTION: An electro-mechanical interface (12) and / or an inductive interface (13) are / is provided in a housing (4), such interfaces (12, 13) are inductively connected with a driving device and / or an evaluating device and / or are connected with electrical track, the interfaces (12, 13) can get close to an external robot arm (14) and are communicated with the robot arm (14) so that electrical data signal and / or electrical energy can be transmitted alternately and bi-directionally between the interfaces (12, 13) of the housing (4) and electro-mechanical interface (12') and / or an inductive interface (13') of the robot arm (14).SELECTED DRAWING: Figure 1a

Description

Technical Field

[0001] The present invention relates to a clamping device for holding a workpiece to be machined by a machine tool, as described in the preamble of claim 1.

Background Art

[0002] Such clamping devices may be used, as is known, as chucks, vice or zero-point clamping systems. In all such clamping devices, a centered arrangement of the workpiece with respect to a reference plane or reference axis, for example, the symmetry axis of the housing, is of extremely technical importance. This is because it is required that the workpiece can be machined by a machine tool with as small an error as possible. For this purpose, it is necessary to grasp the exact position of the workpiece with respect to the reference plane or reference axis and to precisely repeat this clamping position when replacing workpieces of the same structure.

[0003] Unfortunately, at present, the workpiece to be machined has to be manually replaced by an operator. Therefore, each workpiece to be machined has to be removed from the clamping device in order to be able to mount another workpiece in the clamping device after the machining process.

[0004] Furthermore, it has been found that known clamping devices have the drawback that the position of the workpiece changes during mounting and / or during the machining process, based on factors such as centrifugal force of the chuck or rotation of the machine tool's pallet or worktable. During workpiece mounting, particles in the form of chips or other impurities may be present between the workpiece and the clamping jaws, or between the workpiece and the mounting surface assigned to the housing on which the workpiece can be placed flat. These particles can subsequently cause changes in the workpiece's position. Therefore, prior to the start of the machining process by the machine tool, it is necessary to inspect whether the workpiece is properly mounted in the clamping device. However, since workpiece mounting is done manually, and known clamping devices often use hydraulic or mechanical drive mechanisms to move the clamping jaws, inspecting the position of the mounted workpiece is time-consuming and laborious, and operators require considerable technical expertise to perform such controls on the mounted workpiece. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Therefore, the object of the present invention is to improve not only the clamping device described at the beginning but also the clamping device in the form described at the beginning so that automated positional inspection of the mounted workpiece can be performed, and once the inspection result is provided, the start of the machining process can proceed automatically or the position of the workpiece within the clamping device can be inspected. [Means for solving the problem]

[0006] This problem is solved by the features of the feature part of claim 1 according to the present invention.

[0007] Another advantageous modification of the present invention is evident from the dependent claims.

[0008] The housing is provided with an electromechanical interface and / or an inductive interface, which is inductively coupled to a drive unit and / or evaluation unit and / or connected by an electrical line, and the interface is accessible to an external robot arm, and by communicating with the robot arm such 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 performed prior to the commencement of the machining process by the machine tool.

[0009] Advantageously, the robotic arm used for automated inspection of the clamping position of a workpiece within a clamping device may be mounted on a chassis, thereby allowing the robotic arm to move freely within the mounting hole and thus access multiple machine tools to query the clamping parameters of these machine tools. By fixing the robotic arm to the ceiling, crane, or similar, it becomes easy to move the robotic arm within a specified area where the corresponding machine tools are installed.

[0010] The control device assigned to the robot arm chassis may, advantageously, not only control the movement of the robot arm but also query the clamping position of the workpiece against the clamping device. The control device queries the clamping position, and only after confirming that the workpiece is properly clamped does the control device send the appropriate electrical command signal to operate the machine tool. As a result, after the workpiece is mounted in each clamping device, the clamping position of the workpiece can be automatically queried and controlled, and the machining process can be activated when the appropriate measurement result is provided.

[0011] To transmit electrical data signals between the clamping device and the robot arm, the housing is provided with pins or sockets for mechanical and electrical connections. Optionally, an inductive interface in the form of a mounting surface may be present. The free end of the robot arm is provided with a corresponding mechanical or inductive interface, so that the robot arm is mechanically and electrically connected to the housing's mechanical interface during the inspection period, or non-contact data transmission occurs between the robot arm and the housing's inductive interface. Depending on the mechanical and inductive interfaces used, not only electrical data signals but also electrical energy can be transmitted alternately, i.e., bidirectionally, between the clamping device and the robot arm. The robot arm is connected to a control center via an appropriate antenna, WLAN connection, or electrical line, so that evaluated or obtained measurement data can be immediately transmitted from the robot arm to the control space. Thus, a corresponding machine hall containing multiple such machine tools can be centrally monitored and operated by the control space.

[0012] The drawings show embodiments of the clamping device according to the present invention with various structural configurations, and this clamping device will be described in detail below. [Brief explanation of the drawing]

[0013] [Figure 1a] This is a perspective view of a clamping device mounted on a tool table, which holds a workpiece between three clamping jaws and clamps it during the machining process of the machine tool, and a robotic arm mounted on the chassis that automatically positions the workpiece on the clamping device. [Figure 1b] Figure 1a shows a machine tool, clamping device, and robot arm, where the robot arm and clamping device communicate with each other through an electromechanical interface and an inductive interface. [Figure 2a] Figure 1a shows the clamping device, where the robot arm is rotated 90° to align the interfaces with each other. [Figure 2b] This is an enlarged view of the clamping device shown in Figure 2a, seen from another side. [Figure 3] This is an enlarged view of the clamping device shown in Figure 1a, which has been cut to clarify the structure and function of the zero-point clamping system. [Figure 4] Figure 1a shows a clamping device in the form of a vise, comprising two clamping jaws that can approach each other, an electromechanical interface and an inductive interface that are freely accessible from the outside, and a robotic arm positioned adjacent to the housing interface. [Figure 5] This figure shows a machine tool pallet or tool table to which the clamping device shown in Figure 1a, in the form of a chuck, can be attached. [Modes for carrying out the invention]

[0014] Figure 1a shows the loading operation of the workpiece 3 to be machined by the machine tool 2 into the clamping device 1 by the robot arm 14. The robot arm 14 holds the workpiece 3 and places it in the open clamping device 1. This clamping device 1 is formed as a so-called zero-point clamping system. In other words, each workpiece 3 of the same structure produced in mass production can be repeatedly and precisely positioned in the precisely preset position of the clamping device 1, thereby ensuring that the machining steps performed by the machine tool 2 can be carried out within the range of a single tool line without changing the programming.

[0015] In this illustrated embodiment, the clamping device 1 consists of a housing 4. Inside this housing 4 are three clamping jaws 7, 8, and 9. In zero-point clamping systems, such clamping jaws are often called clamping sliders. The functional and structural configuration of the zero-point clamping system is such that a workpiece 3 or a clamping pin coupled to the workpiece 3 is inserted into a housing opening machined in the housing 4. An electrically operated drive unit 11 is provided inside the housing 4. This drive unit 11 causes the clamping jaws 7, 8, and 9 to move synchronously. These clamping jaws 7, 8, and 9 are inserted axially movably into guide grooves (not shown). Each guide groove extends radially with respect to a reference axis 4' corresponding to the axis of symmetry of the housing opening provided in the housing 4.

[0016] The robot arm 14 has a free end 15. On the free end 15, a gripping device for holding the workpiece 3 is located on one side, and on the other side, an electromechanical interface 12' and an inductive interface 13' are located. The outer surface of the housing 4 is provided with the electromechanical interface 12 and the inductive interface 13. Both interfaces 12 and 13 communicate with each of the interfaces 12' and 13' of the robot arm 14 to transmit electrical data signals and electrical energy.

[0017] The robot arm 14 is mounted on the chassis 17. A control device 18 is assigned to this chassis 17. This control device 18 enables the chassis 17 to move automatically on the base, and at the same time, enables the necessary motion flow for the robot arm 14 to be executed according to the position of the chassis 17 or the robot arm 14.

[0018] Figure 1b shows that the robot arm 14 has finished placing the workpiece 3 on the placement surface 6' formed by the housing 4. Therefore, the workpiece 3 is positioned on the preset placement surface 6' by the housing 4. Inside the housing 4, the electric drive device 11 has finished feeding the three clamping jaws 7, 8, 9. By means of structural means, while the clamping jaws 7, 8, 9 are being fed, a pulling force that first presses the workpiece 3 against the placement surface 6' is formed, and at the same time, a radial holding force that positions the workpiece 3 and clamps it to the housing 4 is formed.

[0019] Therefore, if the workpiece 3 is positioned on the placement surface 6' and the clamping jaws 7, 8, 9 are being fed, theoretically, the machining process in the machine tool 2 can be started. However, since the mounting of the workpiece 3 is carried out fully automatically by the robot arm 14, the position of the workpiece 3 relative to the reference surface 6' must be inspected. For this purpose, an electrical evaluation device 11' is provided in the housing 4. This electrical evaluation device 11' is inductively coupled to the electric drive device and / or connected via electrical lines. That is, it is possible to easily measure the rotational speed of the electric drive device 11 and the motion flow related to this rotational speed, and thereby calculate the stroke distance of each clamping jaw 7, 8, 9.

[0020] Furthermore, a plurality of holes 31 may be machined in the placement surface 6'. One proximity sensor 32 is inserted into each of these holes 。This proximity sensor 32 operates inductively and measures the distance between the proximity sensor 32 and the lower surface of the workpiece 3 when the workpiece 3 is positioned. If one of the various measurement results, that is, the stroke distance of each clamping jaw 7, 8, 9 and / or the measurement result of the proximity sensor 32 deviates from the preset tolerance range, this will be detected by the electrical evaluation device 11'.

[0021] Therefore, once the robot arm 14 has finished positioning the workpiece 3 on the mounting surface 6', the robot arm 14 rotates its free end 15 so that the electromechanical interface 12' and inductive interface 13' provided on the free end 15 of the robot arm 14 are aligned with the electromechanical interface 12 and inductive interface 13 of the housing 4. As shown in Figures 2a and 2b illustrating this position, the electromechanical interfaces 12;12' have pins 19 and sockets 21 or, conversely, sockets 20 and pins 22 that are mechanically or electrically connected to each other. Thus, electromechanical or inductive data signal transmission or energy transmission occurs between the robot arm 14 and the electrical components provided inside the housing 4. In particular, electrical energy can be transmitted from the robot arm 14 to the electric drive unit 11 or a battery placed in front of the electric drive unit 11, and the electrical evaluation device 11' can transmit corresponding measurement signals from the proximity sensor 31 to the robot arm 14 or the control device 18 incorporated within the robot arm 14. The control device 18 evaluates the generated measurement signal and compares it with stored data in a pre-programmed query cycle. If the measurement result is within a preset tolerance range, the control device 18 generates an error signal to activate the machine tool 2 via interfaces 12, 12'; 13, 13' or to manually or automatically inspect the position of the workpiece 3. Once the control device 18 has finished transmitting the operation of the machine tool 2, the robot arm 14 is moved away from the housing 4, thereby initiating the machining process by the machine tool 2.

[0022] In FIG. 3, the structural and functional configuration of a zero-point clamping system formed as the clamping device 1 can be recognized. In this figure, it can also be recognized that one or more coils functioning as the transmission and reception device 24 are provided on the inductive interface 13. In this case, the interface 13 forms the operating surface 25. On this operating surface 25, the operating surface 25' provided at the free end 15 of the robot arm 14 can be aligned and disposed in a non-contact manner. Therefore, inductive signal transmission and energy transmission are performed in a non-contact manner. On the other hand, mechanical and electrical connections are required for the pins 19 and the insertion portions 21 arranged in pairs with each other or the insertion portions 20 and the pins 22.

[0023] In FIG. 4, a vice can be recognized as the clamping device 1. This vice has two clamping jaws 7, 8 that can be moved relative to each other. Between these two clamping jaws 7, 8, each workpiece 3 is clamped. On one of the exposed outer surfaces of the housing 4, the electromechanical interface 12 and the inductive interface 13 are arranged. Both interfaces 12, 13 extend in alignment with the electromechanical interface 12' and the inductive interface 13' existing on the robot arm 14 for communication transmission. Therefore, each robot arm 14 can be brought close to an arbitrary clamping device 1 and communicate with this clamping device 1 accordingly. It is solely necessary that the arrangement of the interfaces 12, 13 spatially matches the arrangement of the interfaces 12', 13', and thus, a transition to a mechanical and electrical connection state or an inductive coupling state is made.

[0024] The same applies to the clamping device 1 shown in Figure 5. In the figure, this clamping device 1 is formed as a chuck with three clamping jaws 7, 8, and 9. Each workpiece 3 is mounted and clamped between the clamping jaws 7, 8, and 9. Such a clamping device 1, used as a chuck, often rotates during the machining process, which allows for electromechanical connection or inductive coupling between the interfaces 12;13 and the interfaces 12';13' of the robot arm 14, primarily when the clamping device 1 is at rest.

[0025] The transmission of electrical data signals and electrical energy can be inductively between the drive unit 11, the evaluation device 11', and the proximity sensor 32, as well as by the electrical line 16. [Explanation of symbols]

[0026] 1. Clamping device (zero-point clamping system, vise or chuck) 2 Machine tools 3 Work Clamp pin for 3' 3" 4 Housing 4' Reference axis / Symmetric axis 6' Mounting surface 7,8,9 Clamp jaws 10 Compatible stoppers for vises 11. Drive system, electric type 11' Electrical evaluation device Electromechanical interface located at 12 4 12' 14 electromechanical interface Inductive interface located at 13 4 13' 14" Inductive Interface 14 Robot Arm 15 14 Free end Electrical lines within 16 4 17 14 chassis 18 Control device 19 12 pins 20 12 insertion points 21 14 insertion points 22 14 pins 23 13 operating surface 24 4 Transmitter / Receiver 25 14 operating surface 26 14 Transmitting / receiving devices 27 28 29 30 Basics 31 holes 32 Proximity Sensors

Claims

1. A clamping device (1) for holding a workpiece (3) to be machined by a machine tool (2), comprising: A housing (4); At least one clamp jaw (7) supported on the housing (4) so ​​as to be axially movable and clamping the workpiece (3), and at least one corresponding stopper (10) formed by the housing (4), or at least two clamp jaws (7, 8, 9) supported on the housing (4) so ​​as to be axially movable and clamping the workpiece (3); an electrically operated drive (11) capable of controlling the movement of the movable clamping jaws (7, 8, 9) and generating a holding force during the clamping operation, which is transmitted from the clamping jaws (7, 8, 9) to the workpiece (3) or to a clamping pin (3') connected to the workpiece (3); In a clamping device (1) comprising: the housing (4) is provided with an electromechanical interface (12) and / or an inductive interface (13), which is inductively coupled to the drive device (11) and / or the evaluation device (11′) and / or is connected by an electrical line (16), The interfaces (12, 13) are accessible to an external robot arm (14) and communicate with the robot arm (14) such that electrical data signals and / or electrical energy can be transmitted alternately and bidirectionally between the interfaces (12, 13) of the housing (4) and the electromechanical interface (12') and / or the inductive interface (13') of the robot arm (14). A clamping device (1).

2. the evaluation device (11') is electrically or inductively connected to at least one proximity sensor (32), Each of the proximity sensors (32) measures the position of the workpiece (3) relative to a reference axis (4') of the housing (4) and / or a rest surface (6) assigned to the housing (4), The measurement results determined by each of the proximity sensors (32) are transferred to the evaluation device (11') in the form of electrical data signals. Clamping device (1) according to claim 1, characterised in that it is

3. The robot arm (14) is mounted on a chassis (17), a control device (18) is assigned to the chassis (17) for automating the movement of the chassis (17) and / or the robot arm (14), The control device (18) executes a program for controlling the clamping state of the workpiece (3) in the clamp device (1). Clamping device (1) according to claim 1 or 2, characterized in that it is

4. 4. The clamping device (1) according to claim 3, characterized in that the rotational speed of the drive (11) and / or the stroke distance of the clamping jaws (7, 8, 9) are generated by the control device (18), and measurement results are generated by interrogation, and on the basis of the measurement results, the clamping state of the workpiece (3) is used by the control device (18) for operating the machine tool (2).

5. The electromechanical interface (12) comprises one or more pins (19, 19', ...) or plug-ins (20, 20', ...), The free end (15) of the robot arm (14) is provided with plug-in points (21, 21', ...) or pins (22, 22', ...) that correspond to the pins (19, 19', ...) or plug-in points (20, 20', ...) and are mechanically and electrically connected in pairs. Clamping device (1) according to claim 1, characterised in that it is

6. The inductive interface (13) has an operating surface (23); said operating surface (23) is assigned an inductively operated transmitting and / or receiving device (24), The robot arm (14) has a working surface (25) to which a transmitting and / or receiving device (26) is assigned for communicating with the transmitting and / or receiving device (26) of the interface (25) of the clamping device (1). Clamping device (1) according to claim 1, characterised in that it is

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