CHUCK

Abstract

In the case of a clamping device (1) for holding a workpiece (3) to be machined by a machine tool (2), consisting of a housing (4), at least one clamping jaw (7) mounted in the housing (4) so that it is axially movable 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) mounted in the housing (4) so they are axially movable, between which the workpiece (3) is clamped, and an electrically operated drive device (11), by means of which the movable clamping jaws (7, 8, 9) are movably controlled, and by means of which a holding force, transmitted by the clamping jaws (7, 8, 9) to the workpiece (3) or by a clamping bolt (3′) coupled with the workpiece (3), is generated during the clamping process, both an automated insertion as well as a clamping device (1) are supposed to be further developed, by means of which an automated position check of the inserted workpiece (3) can be carried out, and by means of which, when the test result is available, either the beginning of the machining process is automatically initiated or a check of the position of the workpiece (3) in the clamping device (1) is conducted. This is achieved in that an electromechanical and/or inductive interface (12, 13) is provided on the housing (4), which interface is connected inductively to the drive device (11) and/or an analysis device (11′) and/or by means of electric lines (16), that the interface (12, 13) for an external robotic arm (14) is accessible and communicates with said robotic arm in such a way, that electric data signals and/or electric energy between the interface (12, 13) of the housing (4) and an electromechanical and/or inductive interface (12′, 13′) of the robotic arm (14) can be transmitted alternately and bidirectionally.

Claims

1. A clamping device (1) for holding a workpiece (3) to be machined by a machine tool (2), consisting of: a housing (4), at least one clamping jaw (7) mounted in the housing (4) so that it is axially movable 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) mounted in the housing (4) so they are axially movable, between which the workpiece (3) is clamped, and an electrically operated drive device (11), by means of which the movable clamping jaws (7, 8 9) are movably controlled, and by means of which a holding force, transmitted by the clamping jaws (7, 8, 9) to the workpiece (3) or by a clamping bolt (3′) coupled with the workpiece (3), is generated during the clamping process, characterized in that an electromechanical and/or inductive interface (12, 13) is provided on the housing (4), which interface is connected inductively to the drive device (11) and/or an analysis device (11′) and/or by means of electric lines (16), that the interface (12, 13) for an external robotic arm (14) is accessible and communicates with said robotic arm in such a way, that electric data signals and/or electric energy between the interface (12, 13) of the housing (4) and an electromechanical and/or inductive interface (12′, 13′) of the robotic arm (14) can be transmitted alternately and bidirectionally.

2. The clamping device according to claim 1, characterized in that the analysis device (11′) is connected to at least one proximity sensor (32) electrically or inductively, that by means of the respective proximity sensor (32) the position of the workpiece (3) with respect to a reference axis (4′) of the housing (4) and/or with respect to a supporting surface (6) allocated to the housing (4) is measured, and that the measurement result determined by the respective proximity sensor (32) is relayed to the analysis device (11′) in the form of electric data signals.

3. The clamping device (1) according to claim 1, characterized in that the robotic arm (14) is mounted on a chassis (17), that a control device (18) is allocated to the chassis (17), by means of which the chassis (17) and/or the movements of the robotic arm (14) are moved automatically, and that a program for controlling the clamping situation of the workpiece (3) on the clamping device (1) is cycled through via the control device (18).

4. The clamping device (1) according to claim 3, characterized in that the rotational speed of the drive device (11) and/or the travel path of the clamping jaws (7, 8, 9) is generated by the control device (18), that measurement results are generated through this query, by means of which the clamping situation of the workpiece (3) is used by the control device (18) for an activation of machine tool (2).

5. The clamping device (1) according to claim 1, characterized in that the electromechanical interface (12) has one or more pins (19, 19′ . . . ) or plug-in slots (20, 20′ . . . ), and that on the free ends (15) of the robotic arm (14), plug-in slots (21, 21′ . . . ) or pins (22, 22′ . . . ) corresponding therewith are provided, which are coupled mechanically and electrically in pairs.

6. The clamping device (1) according to claim 1, characterized in that the inductive interface (13) has a push button (23), that an inductively operated transmitting and/or receiving device (24) is allocated to the push button (23), and that the robotic arm (14) has a push button (25), which is allocated a transmitting and/or receiving device (26) for communication with the transmitter and/or receiving device (26) of the interface (25) of the clamping device (1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1a A perspective view of a clamping device mounted on a tool table, by means of which a workpiece is inserted between three clamping jaws and is clamped by said clamping jaws during the machining process of a machine tool, and a robotic arm, which is mounted on a chassis and automatically places the workpiece on the clamping device,

[0015] FIG. 1b The machine tool, the clamping device and the robotic arm according to FIG. 1a, wherein the robotic arm and the clamping device communicate with each other by means of electromechanical and inductive interfaces,

[0016] FIG. 2a The clamping devices' according to FIG. 1a, wherein the robotic arm is rotated by 90°, in order to align the interfaces with each other,

[0017] FIG. 2b An enlarged depiction of the clamping device according to FIG. 2a from another side,

[0018] FIG. 3 An enlarged depiction of the clamping device according to FIG. 1a and with a cutout to clarify the construction and function of a zero point clamping system,

[0019] FIG. 4 The clamping device according to FIG. 1a, in the form of a vice having two clamping jaws that can be advanced toward each other and the electromechanical and inductive interfaces that are freely accessible from the outside as well as the robotic arm, which is arranged adjacent to the interface of the housing, and

[0020] FIG. 5A palette or a tool table or machine tool, on which the clamping device according FIG. 1a can be mounted in the form of a clamping chuck.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1a shows a loading process of a workpiece 3 to be machined by a machine tool 2 on a clamping device 1 by means of a robotic arm 14. The robotic arm 14 holds the workpiece 3 and places it on the opened clamping device 1. The clamping device 1 is designed in this case as a so-called zero point clamping system. This means that every structurally identical workpiece 3 from a production run can be positioned with reproducible accuracy at exactly the predetermined position of the clamping device 1, in order to ensure that the machining steps to be carried out by the machine tool 2 can be performed without reprogramming during a tool series.

[0022] The clamping device 1 in this depicted exemplary embodiment consists of a housing 4, in the interior of which three clamping jaws 7, 8, 9 are arranged. In the case of zero point clamping systems, these types of clamping jaws are frequently also designated as clamping slides. The function and the structural design of a zero point clamping system occurs in such a way that the workpiece 3 or a clamping bolt connected to the workpiece 3 is inserted into a receptacle opening integrated into the housing 4. An electrically operated drive device 11 is provided in the housing 4, by means of which the clamping jaws 7, 8, 9 are moved synchronously. The clamping jaws 7, 8, 9 are thereby inserted in an axially movable manner into guide grooves (not shown); the respective guide grooves run radially on a reference axis 4′, which corresponds to the axis of symmetry of the receptacle opening of the housing 4. The robotic arm 14 has a free end 15, on which firstly a gripping device for holding the workpiece 3 is arranged and secondly an electromechanical and inductive interface 12′ or 13′. Provided on the outer side of the housing 4 is an electromechanical interface 12 and an inductive interface 13, which communicate with the respective interface 12′ or 13′ of the robotic arm 14 to transmit electric data signals and electric energies.

[0023] The robotic arm 14 is mounted on a chassis 17, to which a control device 18 is allocated. By means of the control device 18, the chassis 17 is supposed to be automatically movable on an substrate and, at the same time, the movement sequences required for the robotic arm 14 are supposed to be executable by the control device 18 as a function of the position of the chassis 17 or the robotic arm 14.

[0024] FIG. 1b shows that the robotic arm 14 has placed the workpiece 3 on a supporting surface 6′, which is formed by the housing 4. As a result, the workpiece 3 is resting on the supporting surface 6′ predetermined by the housing 4. In the interior of the housing 4, the electric drive device 11 has advanced the three clamping jaws 7, 8 or 9. As a result of constructive measures, a pull-in force develops during the advancement of the clamping jaws 7, 8, 9, whereby the workpiece 3 is first pressed on the supporting surface 6′, and simultaneously a radial holding force, by means of which the workpiece 3 is tensioned in a specific position with the housing 4.

[0025] When the workpiece 3 is accordingly positioned on the supporting surface 6′ and the clamping jaws 7, 8, 9 are advanced, the machining process on the machine tool 2 can theoretically be started. But since the insertion of the workpiece 3 was carried out fully automatically by the robotic arm 14, the position of the workpiece 3 in relation to the reference surface 6′ must be checked. An electric analysis device 11′ is provided for this purpose in the housing 4, and said device is coupled inductively and/or via electric lines with the electric drive device. It is namely readily possible to measure the rotational speeds and the associated movement sequences of the electric drive device 11 and thereby calculate the travel path of the respective clamping jaw 7, 8, 9.

[0026] In addition, several borehores 31 can be integrated in the supporting surface 6′, in which boreholes a proximity sensor 32 is respectively inserted. The proximity sensors 32 are operated inductively and measure the distance between said proximity sensors and the lower side of the workpiece 3 as soon as it is positioned. If one of the measurement results, i.e., the travel path of the respective clamping jaws 7, 8, 9 and/or the measurement result of the proximity sensor 32, should deviate from a predetermined tolerance range, the electric analysis device 11′ will detect this.

[0027] As soon as the robotic arm 14 places the workpiece 3 on the supporting surface 6′, the robotic arm 14 rotates the free end 15 in such a way that the electromechanical and inductive interfaces 12′, 13′ provided on the free end 15 of the robotic arm 14 are oriented with the electromechanical and inductive interfaces 12 and 13 of the housing 4 so they are aligned with each other. According to FIGS. 2a and 2b, which depict this position, the electromechanical interfaces 12 or 12′ either have pins 19 and plug-in slots 21 or conversely plug-in slots 20 and pins 22, which are coupled mechanically and electrically with each other. Consequently, an electromechanical or inductive data signal or energy transmission occurs between the robotic arm 14 and the electric components provided in the interior of the housing 4. Thus electric energy in particular can be transmitted from the robotic arm 14 to the electric drive device 11 or an accumulator that is upstream therefrom, and the electric analysis device 11′ can transfer corresponding measurement signals from the proximity sensors 31 to the robotic arm 14 and the control device 18 installed therein. The measurement signals that are generated in such a manner are analyzed by the control device 18 and compared with stored data in a preprogrammed query cycle. If the measurement results are within a predetermined tolerance range, the control device 18 activates the machine tool 2 via the interfaces 12, 12′ or 13, 13′ or generates an error signal, in order to check the position of the workpiece 3 manually or automatically. Once the control device 18 has conveyed the activation of the machine tool 2, the robotic arm 14 removes itself from the housing 4, so that the machining process by the machine tool 2 is started.

[0028] FIG. 3 shows the constructive and functional structure of the zero point clamping system designed as a clamping device 1. In this case, it can also be seen that the inductive interface 13 has been provided with one or more coils functioning as transmitting/receiving devices 24. The interface 13 in this case is embodied as a push button 25, to which a push button 25′ can be contactlessly arranged in an aligned manner on the free end 15 of the robotic arm 14. As a result, the inductive signal and energy transmission ensues in a contactless manner; whereas the pins 19 and plug-in slots 21 or plug-in slots 20 and pins 22, which are arranged in pairs to each other, need a mechanical and electrical coupling.

[0029] FIG. 4 shows a vice as a clamping device 1, which has two clamping jaws 7 and 8 that can be advanced toward each other, between which the respective workpiece 3 is clamped. Arranged on one of the free outer sides of the housing 4 are the electromechanical and inductive interfaces 12 or 13, which run in alignment with the electromechanical and inductive interfaces 12′ and 13′ that are present on the robotic arm 14 for the transmission of communication. Consequently, every robotic arm 14 can approach any desired clamping devices 1 in order to correspondingly communicate with them. All that is required is that the arrangement of the interfaces 12 and 13 conforms spatially to the arrangement of the interfaces 12′ and 13′ and is thereby transferred either into a mechanical and electrical or into an inductive coupling state.

[0030] The same applies to the clamping device 1 depicted in FIG. 5, which is designed here as a clamping chuck with three clamping jaws 7, 8 and 9, between which the respective workpiece 3 is inserted and clamped. Often these types of clamping devices 1 that are used as clamping chucks rotate during the machining process, so that an electromechanical or inductive coupling between the interfaces 12, 13 or 12′ and 13′ of the robotic arm 14 can take place only when the clamping device 1 is in an idle state.

[0031] The transmission of electric data signals and the electric energy can take place between the drive device 11, the analysis device 11′ and the proximity sensor 32 both inductively as well as by means of electric lines 16.

TABLE-US-00001 List of Reference Numbers 1  Clamping device (zero point clamping system vice or clamping chuck) 2  Machine tool 3  Workpiece 3′  Clamping bolt for 3 4  Housing 4′  Reference axis/axis of symmetry 6′  Supporting surface 7, 8, 9  Clamping jaw 10  Counter-stop for vice 11  Drive device, electrical 11′  Electric analysis device 12  Electromechanical interface on 4 12′  Electromechanical interface of 14 13  Inductive interface on 4 13′  Inductive interface of 14 14  Robotic arm 15  Free end of 14 16  Electric lines in 4 17  Chassis of 14 18  Control device 19  Pins of 12 20  Plug-in slots of 12 21  Plug-in slots of 14 22  Pins of 14 23  Push button of 13 24  Transmitting/receiving device of 4 25  Push button of 14 26  Transmitting/receiving device of 14 27 28 29 30  Substrate 31  Borehole 32  Proximity sensor