CLAMPING DEVICE WITH EXCAVATION FUNCTION

Abstract

The present invention relates to a clamping device (10) and a method for clamping a workpiece (2), preferably to a machining device, in particular for clamping a workpiece (2) having one or more curved surfaces or free-form surfaces, comprising: a first receiving section (12) for receiving a workpiece (2), which preferably has at least in sections thereof a first negative form relative to the workpiece (2) to be received, a second receiving section (13) for receiving the workpiece (2), which preferably has at least in sections thereof a second negative form relative to the workpiece (2) to be received, wherein one of the receiving sections (12, 13) can be moved out of a first position relative to the other receiving section (12, 13) into a second position, and one or more clamping mechanisms (20a, 20b) is/are provided on the first receiving section (12) and/or on the second receiving section (13).

Claims

1. A clamping device for clamping a workpiece for clamping a workpiece having one or more curved surfaces or free-form surfaces, to a machining device, comprising: a first receiving section for receiving at least in sections thereof a workpiece having at least in sections thereof a first negative form relative to the workpiece to be received, a second receiving section for receiving at least in sections thereof the workpiece having at least in sections thereof a second negative form relative to the workpiece to be received, wherein one of the receiving sections can be moved out of a first position relative to the other receiving section into a second position, and wherein at least one of the receiving sections comprises one or more clamping mechanisms.

2. The clamping device according to claim 1, wherein one receiving section can be raised and/or lowered out of the first position, which is preferably a receiving position, into the second position, which is preferably a finishing position, in particular it can be raised and/or lowered such that a free space can be created.

3. The clamping device according to claim 1, further comprising a base body on which the first receiving section is formed or removably attached, wherein the base body preferably comprises a base plate with which the base body can be attached to a machine table of a machining device.

4. The clamping device according to claim 1, wherein the clamping mechanisms are formed as a vacuum area and/or as a suction element.

5. The clamping device according to claim 1, wherein a first clamping mechanisms, which are provided on the first receiving section, can be supplied with negative pressure separately from a second clamping mechanism, which are provided on the second receiving section.

6. The clamping device according to claim 1, wherein a negative form of the first receiving section and/or the second receiving section, relative to the workpiece to be received, is formed at least in sections thereof by the clamping mechanisms and/or a receiving profile and/or locating pins, wherein the receiving profile is preferably formed of aluminum, plastics material or rubber.

7. The clamping device according to claim 1, wherein the first and/or the second receiving section can be moved continuously or incrementally relative to the other receiving section, wherein the first and/or second receiving section can be moved in a vertical direction, perpendicular to a base plate of a base body of the clamping device.

8. The clamping device according to claim 1, further comprising at least one further receiving section, which can be moved out of a first position relative to the first and/or second receiving section into a second position, wherein the at least one further receiving section comprises one or more clamping mechanisms.

9. The clamping device according to claim 1, wherein a drive and/or drives is/are provided for the first and/or second receiving section and/or the at least one further receiving section so as to facilitate the movement of the first and/or second receiving section and/or the at least one further receiving section.

10. The clamping device according to claim 9, wherein the drive or drives is/are configured in the form of a pneumatic or hydraulic lifting cylinder, an electric lifting spindle drive or a linear motor.

11. The clamping device according to claim 1, wherein the first receiving section is arranged so as to be radially outside of the second receiving section.

12. The clamping device according to claim 1, further comprising a locking device for the first and/or second receiving section and/or for the at least one further receiving section, so as to facilitate the locking of the first and/or second receiving section and/or the at least one further receiving section in one position.

13. The clamping device according to claim 1, further comprising a vacuum source or a vacuum connection, by means of which the one or more clamping mechanisms can be supplied with negative pressure.

14. A method for clamping a workpiece having one or more curved surfaces or free-form surfaces, using the clamping device according to claim 1, comprising the steps of: placing a workpiece in the region of a first and/or second receiving section, wherein the first and/or second receiving section each having at least in sections thereof a negative form relative to the workpiece to be received, holding the workpiece using one or more clamping mechanisms which is/are provided on the first and/or second receiving section and is/are in contact with the workpiece, carrying out a first machining process on the held workpiece, wherein the first machining process is a main machining process, moving one of the receiving sections out of a first position into a second position, and carrying out a second machining process on the held workpiece, wherein the second machining process is a finishing process.

15. The method according to claim 14, further comprising the step of: locking the receiving, section that has been moved in the second position by way of a positive or non-positive connection.

16. The method according to claim 14, wherein prior to the movement of one of the receiving sections being moved into the second position, the workpiece is released by the one or more clamping mechanisms of the other receiving section, and wherein the method comprises the further steps of: relatively moving the receiving section in the second position back into the first position releasing the workpiece from the one or more clamping mechanisms that are provided on the receiving section that has been moved back, and removing the workpiece from the receiving device.

17. A machining device for machining a workpiece having one or more curved surfaces or free-form surfaces, comprising a clamping device according to claim 1 and a machining assembly, for machining the workpiece, wherein the machining device further comprises: a unit that is movable relative to the clamping device wherein the movable unit accommodates the machining assembly.

18. The machining device according to claim 17, further comprising: an attachment device, by means of which a base body of the clamping device can be attached to a machine table of the machining device, wherein the attachment device comprises a supply interface with which the receiving device can be supplied with power and/or negative pressure and/or compressed air.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG. 1 shows a spatial representation of one embodiment of the clamping device according to the present invention, in which both receiving sections are formed as vacuum areas,

[0066] FIG. 2 shows a spatial representation of the clamping device shown in FIG. 1, wherein the workpiece is placed on the second receiving section,

[0067] FIG. 3 shows a sectional view of the embodiment of the clamping device according to the present invention as shown in FIG. 1 and FIG. 2, which is in the receiving position,

[0068] FIG. 4 shows a sectional view of an alternative embodiment of the clamping device according to the present invention, in which the first receiving section is formed as vacuum areas and the second receiving section is formed as suction plates,

[0069] FIG. 5 shows a sectional view of the embodiment of the clamping device as shown in

[0070] FIG. 4, wherein the clamping device is in the receiving position,

[0071] FIG. 6 shows a spatial representation of the embodiment of the clamping device as shown in FIG. 5,

[0072] FIG. 7 shows a sectional view of a further alternative embodiment of the clamping device according to the present invention,

[0073] FIG. 8 shows a spatial representation of a further embodiment of the clamping device according to the present invention, and

[0074] FIG. 9 shows a flow diagram of one embodiment of a method for clamping a workpiece having free-form surfaces as according to the present invention, preferably using the clamping device according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] In the following, preferred embodiments of the present invention will be described in detail on the basis of the enclosed drawings. Further modifications cited in this context of certain features can each individually be combined in order to form new embodiments.

[0076] FIG. 1 shows a clamping device 10 comprising a base body 11. Within the scope of the preferred embodiment described, this is a clamping device 10 for receiving a workpiece 2 consisting of fiber composite material which has, for example, a U-shaped profile form as shown in FIG. 1. A first receiving section 12 is formed on the base body 11 which serves to facilitate the attachment of the clamping device 10 to a machine table (not shown) of a machining device. As can also be derived from FIG. 1, the first receiving section 12 faces the workpiece 2 to be received. For the sake of clarity the workpiece 2 is shown above the clamping device 10, i.e. in a state not yet received by the clamping device 10. Moreover, also for the sake of clarity the clamping device 10 shown is pictured in a raised position. This will be addressed in detail later on.

[0077] As FIG. 1 also shows, the first receiving section 12 is formed on the entire upper surface of the base body 11, although this is not strictly necessary. Furthermore, the upper surface of the base body 11 and therefore the first receiving section are designed such that they have a so-called negative form relative to the workpiece 2 to be received. To this end, the front side of the base body 11 (front left in FIG. 1) is designed to be lower than the rear side in the longitudinal direction of the base body 11, which corresponds to the longitudinal direction of the workpiece 2, and lies on the Y axis. Moreover, two central regions are formed at the two ends of the first receiving section 12, which conform in terms of the form thereof to the outer contour of the workpiece. The base body 11 also comprises widened portions 11b, which extend, for example, along the X axis and serve to widen the first receiving region 12 in order to be able to securely receive the workpiece 2 in accordance with the expansion of the workpiece 2 along the X axis.

[0078] Furthermore, the base body 11 comprises a recess 15, in which a second receiving section 13 is formed. In the recess 15, in particular in a front and rear region thereof, two lifting members 30 are accommodated. A part of the second receiving section 13 is formed on each of the upper surfaces of the two lifting members 30, which in turn face the workpiece 2 to be received. In the embodiment of the clamping device 10 shown, both receiving sections 12, 13 are formed as vacuum areas. This means that the surfaces of the base body 11 that come into contact with the workpiece 2, as well as those of the lifting members 30, are provided with bore holes 31 which can be supplied with negative pressure or a vacuum via vacuum channels 32.

[0079] The lifting members 30 also comprise a U-shaped depression on each of the upper surfaces thereof, which extends in the longitudinal direction of the base body 11. In this way, the sides of the workpiece 2 can be partially surrounded by the surfaces of the lifting members 30, as a result of which the workpiece 2 can be securely received.

[0080] FIG. 2 shows a spatial representation of the embodiment of the clamping device 10 according to the present invention as shown in FIG. 1, wherein the workpiece 2 is placed on the second receiving section 13 and the clamping device 10 is in the raised position. As can be derived from FIG. 2, the workpiece 2 is supported to the sides thereof by the U-shape of the two lifting members 30, as a consequence of which the workpiece 2 can be securely received. As can also be derived from FIG. 2, the workpiece 2 is not lying on the first receiving section 12.

[0081] FIG. 3 shows a sectional view of the embodiments of the clamping device 10 according to the present invention as shown in FIGS. 1 and 2, which is in the receiving position here too. Contrary to FIG. 1 and FIG. 2, however, the workpiece 2 is additionally received by the first receiving section 12, as a result of which the workpiece 2 can be held more tightly by the clamping device 10, and in particular it can absorb greater process forces that may be present during the main machining of the workpiece 2. As can also be derived from FIG. 3, the two lifting members 30 each comprise two guide shafts 34, by means of which the lifting members 30 are received in the base body 11 and can be moved in the vertical direction (Z direction). The guide shafts 34 also comprise vacuum channels 32, by means of which the bore holes 31 can be supplied with negative pressure.

[0082] FIG. 4 shows a sectional view of an alternative embodiment of the clamping device 10 according to the present invention, in which the first receiving section 12 is formed as vacuum areas 20a and the second receiving section 13 is formed as suction plates 33, wherein the clamping device 10 is in a raised position in which the workpiece 2 is received and clamped only by the second receiving section 13. As is clear to see from FIG. 4, owing to the raised position it is possible to create a free space 40 beneath the received workpiece 2, and as a consequence it is possible to machine the workpiece 2 at least in part from underneath, without having to reclamp the workpiece 2.

[0083] FIG. 4 also clearly shows the bore holes 31 and the vacuum channels 32 of the vacuum regions 20a of the first receiving section 12 as well as the suction plates 33 of the second receiving section 13. As can also be derived from FIG. 4, the base body 11 is provided with a vacuum connection 11c, by means of which the vacuum regions 20a can be supplied with negative pressure. With respect to the bore holes 31 and/or the suction plates 33, it can be advantageous to be able to supply these with negative pressure separately or at least in groups. This offers the advantage that different workpieces 2 can optionally be received with the same clamping device 10, since the bore holes 31 and/or the suction plates 33, which do not come into contact with the workpiece 2 to be received, can be separated, as a result of which no unnecessary circulating air is sucked in.

[0084] Furthermore, the embodiment of the clamping mechanisms as suction plates 33 offers the advantage that greater tolerance ranges can be covered than with the embodiment as vacuum areas 20a. This means that in the case of the vacuum areas 20a, which are generally formed from materials having a low level of elasticity, there are relatively high requirements in terms of tolerance compliance/dimensional accuracy, since otherwise a vacuum cannot be formed between the workpiece 2 and vacuum area 20a, and yet this is necessary in order to suck the workpiece 2 to the vacuum area 20a, thereby fixing or clamping it thereto. By contrast, with the use of suction elements, in particular suction plates 33, these have a certain degree of plasticity or deflectability, and as a consequence the suction plates 33 can adapt to the shape of the workpiece 2. This firstly offers the advantage that the requirements made of the workpiece 2 and/or the second receiving section 13 in terms of tolerance compliance do not have to be so high, and secondly it offers the advantage that different workpieces 2 having outer contours that are at least very similar can optionally be held by the same clamping device 10. In this way it is possible to reduce the set-up time. In this regard a combination of vacuum areas 20a and suction plates 33 is also conceivable for the first receiving section 12 and/or the second receiving section 13. Thus, vacuum areas 20a could be provided in regions in which different workpieces 2 have the same outer contour, and suction plates 33 could be used in regions in which the outer contours of the individual workpieces 2 are slightly different from each other.

[0085] FIG. 5 shows a sectional view of the embodiment of the clamping device 10 shown in FIG. 4, wherein the clamping device 10 is in the receiving position. This means that the workpiece 2 is received and clamped by both receiving sections 12 and 13. Accordingly, the two lifting members 30 comprising the second receiving section 13 are lowered as compared to the raised position shown in FIG. 4, and therefore they are brought into the receiving position. In the receiving position, surfaces of the lifting members 30 are at approximately the same height as the surface of the base body 11, as a result of which the component to be received can be received simultaneously by both receiving sections 12, 13, and can be clamped by all of the clamping mechanisms (vacuum areas 20a and suction plates 33) that come into contact with the workpiece 2. In this way a maximum clamping force can be exerted on the workpiece 2, and therefore the greatest process forces can be absorbed by the clamping device 10.

[0086] FIG. 6 shows a spatial representation of the embodiment of the clamping device 10 according to the present invention as shown in FIG. 5, wherein the workpiece 2 is not shown. FIG. 6 reveals the individual suction plates 33 of the second receiving section 13, which are attached to the upper surface of the two lifting cylinders 30, as well as the vacuum regions 20a, in particular the bore holes 31 of the vacuum regions 20a, of the first receiving section 12.

[0087] FIG. 7 shows a sectional view of a further alternative embodiment of the clamping device 10 according to the present invention, wherein a third lifting member 30 is provided, and a third receiving section 14 is provided on the surface thereof. In the embodiment shown, the third receiving section 14 also comprises suction plates 33. As can also be derived from FIG. 7, the third main body 30 is positioned so as to be slightly below the other two lifting members 30. This means that in the state shown, only the two lifting members 30 already known are in contact with the workpiece 2, or in particular the suction plates 33 thereof, while the third receiving section 14, and in particular the suction plates 33 thereof, is not in contact with the workpiece 2. Accordingly, a free space 41 is created between the third receiving section 14 and the workpiece 2, which facilitates the machining of the workpiece 2 from underneath. If the workpiece is now to be machined in the region of the underside thereof, for which it was previously held by the second receiving section 13, the workpiece 2 can first of all be received and clamped by the third receiving section 13 and subsequently, for example, the contact between the front (shown on the left in FIG. 7) second receiving section 13 and the workpiece can be broken and the front-most lifting member 30 (shown on the left in FIG. 7) can be lowered.

[0088] Furthermore, FIG. 8 shows a spatial representation of a further embodiment of the clamping device 10 according to the present invention. As can be derived from FIG. 8, the clamping device 10 according to the embodiment shown comprises a base body 11, on the upper surface of which a negative form is formed, corresponding to the contour of the workpiece 2 to be received, wherein the negative form forms a first receiving section 12. As can also be derived from FIG. 8, two second receiving sections 13 are provided, which take the form of two separate clamping units that are accommodated in the base body 11.

[0089] The two clamping units each comprise a plurality of locating pins 50, which are arranged in a circle around a suction device 51, in particular a suction gripper, wherein the suction device 51 is arranged in the center of the locating pins 50. The locating pins 50 are configured to be able to scan and therefore replicate the outer contour of the workpiece 2 to be received. In this way it is possible to form a negative form of the workpiece 2 using the locating pins 50. Once the negative form has been formed by the locating pins 50 these can be fixed in place.

[0090] In order for a workpiece 2 to be able to be received and clamped by the clamping units, once the workpiece 2 has been put in place a negative pressure is applied to the suction device 51, in particular the suction gripper, which is in contact with the workpiece 2, as a result of which the workpiece 2 is sucked and pressed against the locating pins 50. In this way it is possible to clamp and therefore to fix the workpiece 2 into the two clamping units.

[0091] FIG. 8 shows by way of example the clamping device 10 in the finishing position. This means that the first receiving section 12, which is formed on the base body 11, and the two second receiving sections 13, which are formed by the two clamping units, are spaced apart from one another, in particular in the vertical direction. In this regard it is advantageous if the base body 11 can be lowered out of the receiving position (first position) into the finishing position (second position), i.e. if the first receiving section 12 can be lowered downwards. In this way it is possible to create a free space underneath the workpiece 2 for finishing, without having to move the workpiece 2. This is particularly advantageous with respect to machining tolerances.

[0092] FIG. 9 shows a flow diagram of one embodiment of a method for clamping a workpiece having curved surfaces or free-form surfaces as according to the present invention, preferably using the clamping device according to the invention.

[0093] In step 1, a workpiece 2 to be machined is placed into the clamping device 10 which is in the receiving position. This means that the workpiece 2 is brought into contact with the first receiving section 12 and the second receiving section 13, in particular with the clamping mechanisms 20a, 20b of the two receiving sections 12, 13.

[0094] In step 2, a vacuum is applied to the plurality of clamping mechanisms 20a, 20b provided on the first and second receiving sections, as a result of which negative pressure is built up between the clamping mechanisms 20a, 20b and the workpiece 2 and therefore the workpiece 2 is held.

[0095] In the subsequent step, step 3, the main machining can then be carried out on the workpiece 2 that has been received and clamped. Main machining is to be understood here to be machining or a machining process during which maximum process forces can be exerted on the workpiece 2. This means that the workpiece 2 has to be held extremely well and securely in the clamping device 10, and this can be ensured by the holding force of the two receiving sections 12 and 13. The main machining may be, among other things, machining, in particular milling, boring, grinding or sawing.

[0096] Once the main machining is complete, the workpiece 2 is released from the first clamping mechanisms 20a of the first receiving section 12 in step 4. To this end the supply of the first clamping mechanisms 20a with negative pressure is stopped. A compressed air device may optionally be provided, which accelerates the release of the vacuum.

[0097] Once the workpiece 2 has been released from the first clamping mechanisms 20a, in step 5 the two lifting members 30 of the clamping device 10 are raised, in particular into a desired raised position. The workpiece 2, which is still accommodated and clamped in the second receiving section 13, is thereby brought into a raised position, as a result of which a free space can be created beneath and optionally to the side of the workpiece 2.

[0098] In step 6 the finishing of the workpiece 2 can then be carried out. If desired, a plurality of finishing processes different from one another can also be carried out. Finishing is to be understood here to be a machining process during which lower process forces are exerted on the workpiece 2 than are exerted during the main machining. For this reason, in spite of a reduced holding force provided by just the second receiving section, the workpiece 2 can be held and fixed in a satisfactory manner.

[0099] The finishing process may be, for example, deburring, grinding, buffing, sealing, varnishing and the like.

[0100] In accordance with the description of FIG. 7, the second receiving section 13 may if necessary be partially replaced by the third receiving section 14 in order to create a free space beneath or to the side at a different part of the workpiece 2.

[0101] In step 7, once all the finishing processes have been completed, the workpiece 2 is released from the second clamping mechanisms 20b of the second receiving section by the vacuum also being released, as has already been described with respect to step 4.

[0102] Once the vacuum between the workpiece 2 and the second clamping mechanisms 20b has been completely released, the finished workpiece 2 can in step 8 be removed from the clamping device 10 and the clamping device 10 can optionally be brought back into the receiving position.