Apparatus and method for clamping sheet-metal components description

Abstract

The invention relates to an apparatus and method for clamping components (12) during machining, in particular during welding of sheet-metal components arranged in two or multiple layers, having a holder (10) for a machining head (11), in particular for a laser machining head, which can be fitted on an industrial robot in order to guide the machining head (11) along a machining line, a pressure-exerting element (14) which is fitted on the holder (10) in a movable fashion relative thereto, and a pressure-exerting device (17) which is provided operatively between holder (10) and pressure-exerting element (14), with the aid of which the pressure-exerting element (14) can be moved relative to the holder (10). In order to enable controlled pressing of the components (12), in particular in the case of sheet-metal components, without the existence of the risk of damage, the pressure-exerting device (17) has a first actuating element (18) for moving the pressure-exerting element (14) relative to the holder (10) into a first direction, and a second actuating element (21) for moving the pressure-exerting element (14) into a second direction which is opposite to the first direction. The pressure-exerting device (17) is controlled in this case by a force-setting device (28, 30) in order to set the clamping force (F). It is thereby possible during machining, in particular during welding, for the components (12) to be pressed against one another by means of the pressure-exerting element (14) in the region of a machining zone, in particular a welding zone, a clamping force (F) exerted on the sheet-metal components by the pressure-exerting element being set by the counterplay of the two actuating devices.

Description

The invention is explained in more detail below by way of example with the aid of the drawing, in which:

FIG. 1 shows a greatly simplified diagrammatic view of a clamping apparatus according to the invention,

FIG. 2 shows a block diagram intended to illustrate the control of the apparatus according to the invention, and

FIG. 3 shows a simplified diagrammatic view of another clamping apparatus according to the invention.

Claims

1. Apparatus for clamping components (12) during machining, in particular during welding of sheet-metal components arranged in two or multiple layers, having a holder (10) for a machining head (11), in particular for a laser machining head, which can be fitted on an industrial robot in order to guide the machining head (11) along a machining line,a pressure-exerting element (14) which is fitted on the holder (10) in a movable fashion relative thereto,a pressure-exerting device (17) which is provided operatively between holder (10) and pressure-exerting element (14) and has a first actuating element (18) for moving the pressure-exerting element (14) relative to the holder (10) into a first direction, and a second actuating element (21) for moving the pressure-exerting element (14) into a second direction which is opposite to the first direction, anda force-setting device (28, 30) which controls the pressure-exerting device (17) appropriately in order to set the clamping force (F).

2. Apparatus according to claim 1, characterized in that the first and second actuating elements of the pressure-exerting device (17) are hydraulic or pneumatic actuating elements (18, 21).

3. Apparatus according to claim 2, characterized in that hydraulic or pneumatic contraction or expansion elements are provided as actuating elements (18, 21) of the pressure-exerting device (17).

4. Apparatus according to claim 2, characterized in that pressure fluid can be applied from a hydraulic or pneumatic pressure source (29) to the first and second actuating elements (18, 21) via an electrically controllable valve arrangement (28) of the force-setting device (28, 30).

5. Apparatus according to claim 4, characterized in that the electrically controllable valve arrangement comprises a proportional valve (29).

6. Apparatus according to claim 1, characterized in that the pressure-exerting element (14) is fitted on the holder (10) in a linearly displaceable fashion.

7. Apparatus according to claim 1, characterized in that a pressure-exerting roller (14) is provided as pressure-exerting element.

8. Apparatus according to claim 1, characterized by the provision of a force sensor (25) which detects a clamping force exerted by the pressure-exerting element (14) on the component (12) and whose output signal corresponding to the detected clamping force (Fact) is fed to the force-setting device (28, 30), which controls the pressure-exerting device (17) as a function of the output signal of the force sensor (25) in order to set the clamping force (F) to a desired value (Fdes).

9. Apparatus according to claim 8, characterized in that the force-setting device (28, 30) comprises a force-setting circle (30) which compares the output signal, corresponding to the detected clamping force (Fact), of the force sensor (25) with the desired value (Fdes) of the clamping force (F), and which supplies a control signal to the valve arrangement (28) in order to control the pressure fluid feed from the hydraulic or pneumatic pressure source (29) to the pressure-exerting device (17) such that the clamping force (F) is regulated to its desired value (Fdes).

10. Apparatus according to claim 9, characterized in that the desired value (Fdes) of the clamping force (F) can be permanently prescribed for a machining operation.

11. Apparatus according to claim 9, characterized in that the desired value (Fdes) of the clamping force (F) can be variably prescribed for a machining operation in accordance with the machining cycle.

12. Apparatus according to claim 1, characterized in that provided for the purpose of observing at least one property of a machining path right in front of a current machining area, in particular for observing the width of a gap between two components (12) to be welded, is a monitoring device, preferably an optical monitoring device, in particular a video camera with an associated image processing device which varies the desired value (Fdes) of the clamping force (F) during a machining operation in accordance with the detected property of the machining path, in particular in accordance with the detected gap width.

13. Apparatus according to claim 1, characterized in that the machining head (11) is fitted on the holder (10) in a fashion which can be moved relative to the pressure-exerting device (17).

14. Apparatus according to claim 12, characterized in that the movement of the machining head (11) relative to the pressure-exerting device (17) and transverse to the machining line is performed as a function of an output signal of the monitoring device (27) which corresponds to the course of the machining line.

15. Method for clamping components (12) during machining by means of a machining head, in particular during welding of sheet-metal components arranged in two or multiple layers, in the case of which the components (12) are pressed against one another by means of a pressure-exerting element (14) in the region of a machining zone, in particular a welding zone, in which, in order to set the exerted clamping force (F), the pressure-exerting element (14) is moved in a first direction relative to the holder (10) by a force-setting device (28, 30) by means of a first actuating element (18), and in a second direction, opposite to the first direction, by means of a second actuating element (21).

16. Method according to claim 15, characterized in that the first and second actuating elements (18, 21) are actuated hydraulically or pneumatically.

17. Method according to claim 16, characterized in that the actuating elements (18, 21) are contracted or expanded hydraulically or pneumatically in the direction of movement.

18. Method according to claim 16, characterized in that pressure fluid is applied from a hydraulic or pneumatic pressure source (29) to the first and second actuating elements (18, 21) via an electrically controlled valve arrangement (28) of a force-setting device (28, 30).

19. Method according to claim 18, characterized in that the electrically controllable valve arrangement comprises a proportional valve (28).

20. Method according to claim 15, characterized in that the pressure-exerting element (14) is linearly displaced in a fashion substantially perpendicular to the components and relative to a holder (10) for the machining head (11) which is fitted on an industrial robot or the like.

21. Method according to claim 15, characterized in that the clamping force (F) exerted by the pressure-exerting element (14) on the sheet-metal components is detected,the detected clamping force (Fact) is compared with a desired value (Fdes), andthe exerted clamping force (F) is regulated in accordance with the result of comparison.

22. Method according to claim 21, characterized in that the exerted clamping force (F) is detected by means of a force sensor (25) whose output signal corresponding to the detected clamping force (Fact) is compared by a force-setting circle (30) with the desired value (Fdes) of the clamping force (F), anda control signal corresponding to the result of comparison is supplied by the force-setting circle (30) to a valve arrangement (28) in order to control the pressure fluid feed from the hydraulic or pneumatic pressure source (29) to the actuating elements (18, 21) such that the clamping force (F) is regulated to its desired value (Fdes).

23. Method according to claim 22, characterized in that the desired value (Fdes) of the clamping force (F) is permanently prescribed for a machining operation.

24. Method according to claim 22, characterized in that the desired value (Fdes) of the clamping force (F) is variably prescribed for a machining operation in accordance with the machining cycle.

25. Method according to claim 15, characterized in that at least one property of a machining path is monitored right in front of a current machining area, in particular the width of a gap between two sheet-metal components to be welded, by means of a monitoring device (27), preferably an optical monitoring device, in particular a video camera with an associated image processing device.

26. Method according to claim 25, characterized in that the desired value (Fdes) of the clamping force (F) is varied during a machining operation in accordance with the detected property of the machining path, in particular in accordance with the detected gap width.

27. Method according to claim 25, characterized in that the machining head (11) is moved relative to the pressure-exerting device (17) and transverse to the machining line as a function of an output signal of the monitoring device (27) which corresponds to the course of the machining line.