DE4340818C2 - Clamping device for a workpiece - Google Patents

Description

The invention relates to a clamping device for a plant piece.

There are clamping devices at processing stations known a worktop with which a pallet in which a workpiece is held between clamping jaws via Befe Stigungselemente is connectable. Such processing measure Machines are often provided with a measuring device which the position data of the workpiece, based on a tunable zero point position of the clamping table as well as the ho the horizontal alignment position of the workpiece can be determined. Ent The processing station is provided with these position data Execution of a machining process controlled so that the Workpiece is machined correctly. Before the start of this Be work process must, however, a horizontal alignment processing of the workpiece so that it is a machining side facing tool with mostly flat ground Surface is exactly aligned with the processing tool.

With such processing stations, the machine runtime is relatively low, as long as the workpiece position is determined and that Workpiece is aligned horizontally, no machining can be carried out. It is also disadvantageous that Such processing stations so far only by means of very com pleated jaws a horizontal alignment of the work allow one piece.

DE 41 00 148 A1 discloses a pallet for receiving and transporting of workpieces. This pallet has two adjustable with respect to each other Bake on. Threaded spindles are used for adjustment. The regarding each other displaceable jaws have contours that can accommodate different Workpieces are formed.

CH 668 733 A5 discloses a device for mounting and processing of a workpiece, which device also two with respect to each other has displaceable clamping jaws. One of the jaws is relative one frame firmly, while the other by clamping means such. B. hydraulically or pneumatically operated pressure drives, for clamping or relocatable to release a workpiece.

A processing device is known from EP 0 267 352 A2 which a workpiece is fixed on a first coupling part, which first coupling part then on a machine tool-fixed second Coupling part can be attached. To connect these two Coupling parts have mutually associated profile areas. On one A workpiece to be machined is first placed on the first one Coupling part positioned so that it is related to the for machining this workpiece provided a defined machine tools Takes reference position or in a for processing by these machines correct position. In the following, the first one carrying this workpiece becomes Coupling part then on the machine tool-fixed second coupling part arranged to be able to process the workpiece.

The catalog "Bosch, Flexible Automation, The new TS 2 , transfer technology with system for loads up to 30 kg and 480 × 800 mm workpiece carrier base area" shows the use of workpiece carriers in larger machining stations, whereby the transfer of a workpiece to be machined is carried out by position data acquisition and transmission is organized between different workstations.

DE 37 22 524 A1 also discloses a production line trained machining system, in which on workpiece carriers machining workpieces using different tools Processing stations are promoted. The system works automatically, whereby both the position of the workpiece carrier is regulated automatically, as also the sequence of the different processing stations, which from one the workpiece to be machined should be run through under numerical Control stand.

From the subsequently published German patent application DE 432 625 A1 is a method for positioning a workpiece carrier in a Processing machine known, in which in a first station Workpiece holder is equipped with a workpiece to be machined and the Position of the workpiece in the workpiece carrier is detected. In a second Machining station, the workpiece is then machined, referring to the previous one determined position data of the workpiece is used. Between In both stations, the workpiece fixed to the workpiece carrier is put together transferred with this workpiece carrier.

The invention is based on the object of a clamping device train that a determination of location data of the  Workpiece and its horizontal alignment no longer a processing station must be carried out.

This object is achieved by the im Claim 1 specified clamping device solved.

By the measure, a pre-setup station with an up form the clamping table with that of the machining station is identical, the location data of the Workpiece relative to a predeterminable zero point position of the clamping table and on the other hand the workpiece be aligned horizontally without the pallet in the processing station. These preparations can consequently be made while at the same time on the Bear processing station a processing operation is carried out. After completing the latter, the can in the pre-setting station picked up pallet after loosening the fasteners this station will be removed after being at the Be work station the pallet with the previously processed Workpiece is removed, such on the clamping table of the loading Workstation attached that the workpiece exactly same relative position compared to the zero position of this Take up the clamping table as before on the clamping table Voreinrichtstation. To attach the pallet to each because of the worktable inaccuracies caused by game between pallet and worktable, exclude the fasteners with both Pallet as well as with the clamping table by jamming brought into engagement. This ensures it represents that the location recorded in the pre-setting station data and the horizontal alignment of the Workpiece also remains unchanged at the processing station are. The fasteners are also used for Attach the pallet to the worktop and to its zen opposite the worktop.  

By arranging the holding means between the workpiece and the Clamping jaws can be used for the holding means and thus the workpiece Initiation of an actuating movement on one of the actuating means easily in a direction perpendicular to that between instep bake and workpiece acting clamping force are moved. The holding means preferably grip according to claim 2 in the horizontal direction on the outer edge of the workpiece on the one hand a shifting of the holding means in the vertical Direction to horizontal alignment of the workpiece possible and on the other hand the side facing a tool keep the workpiece free, so that the tool is belie biger place of this preferably flat ground side of the Can attack the workpiece on the same.

The curvatures on the sides of the workpiece facing the Holding means according to claim 3, which according to claim 4 are preferably convex, with the aim of Attack the holding means on the workpiece a contact line let arise, their position relative to the workpiece in Ab depending on the course of the curvature can be specified precisely. Is the curvature according to claim 4 so designed that the contact line runs horizontally, so movements are one Holding means perpendicular to the contact line possible without any problems, because the workpiece is practically open when carried along by this movement unwinds the holding means while it continues through them is held non-positively. The said vertical movements of the holding means are reali by the respective adjusting means sierbar.

In claim 5 is a very simple design for Retention means specified. This will be before clamping one Workpiece placed on the jaws of the pallet in such a way that a leg of the respective holding means on the top of the Jaw and the other leg on the workpiece facing front comes to the plant. So created who which the holding means force after clamping the workpiece held conclusively between this and the jaws. A  additional fastening of the holding means to the clamping jaw is necessary righteous.

By placing the actuator according to claim 6 on the This is the jaw when initiating a movement in the Positioning device as a fixed support bearing for the positioning device effective. The holding means engages in an area of the actuator by means of, in which, unlike the support bearing, a conducted movement is also transferred to the Holding device on which a vertical movement is triggered. In Claim 7 is an advantageous embodiment of such Adjustment means specified.

The claim 8 is directed to a fastener, through that in a particularly simple manner, namely by means of a Screw the pallet to be attached to a worktop can, being about the insertion depth of the screw into the thread drilling the clamping table the strength of the frictional connection the pallet is adjustable with the clamping table, because at too depth of insertion of the conical housing part of the fastener tion element increasingly pulled into the recess of the pallet and thereby jammed against this while the same the wedge in front of the housing attachment for widening is moved. The tapered body of the Befe Stigungselementes is particularly good in the recess the pallet, if this is also ko according to claim 9 is nich trained. According to one specified in claim 10 Execution of the conical housing part of the attachment element and the outer wall of the recess in the pallet, related to their respective center axis, the same angle on whose optimal range is mentioned in claim 10.

The guide of the conical housing part of a fastening element in the associated recess of the pallet further improved if this recess according to claim 11 Has contact ribs for the conical housing part, since here through precisely defined contact lines between the conical  Housing part of the fastener and the recess ge be formed. In claim 12 is a preferred embodiment this recess indicated with contact ribs.

The claim 13 is for a design of the housing approach directed a fastener through which a elastic expansion can be done by using the tongues be deflected outwards by the wedge. This housing Approach is special due to the measure according to claim 14 easily into the assigned recess of the clamping table feasible.

In claim 15 is an advantageous embodiment of the wedge elastic expansion of the housing attachment of a fastening element specified. Since the sleeve surrounds the screw, it can on the inside of the elastically expandable housing set simply in that the Screw deeper into the recesses on the clamping table rotated and thereby the sleeve towards the housing attachment is moved, where the conical stamp the tongues after presses radially on the outside, making the housing extension elastic expands. A particularly uniform expansion results if the stamp of the sleeve, based on the central axis of the Fastener, has the same angle as the conical section on the inside of the housing attachment. On An advantageous range of this angle is in claim 17 give, which is selected so that the clamping force between the stamp and the housing approach only become so large can that the sleeve when releasing the pallet from the respective Clamping table easily removed from the housing attachment is distant.

An exemplary embodiment of the invention is described below a drawing explained in more detail. It shows:  

Figure 1 is a plan view of a pallet with holding means for a workpiece and with fasteners for connection to a clamping table.

Figure 2 is a sectional view of the holding means along the line II-II in Fig. 1.

Figure 3 is a partial sectional view of the fastening element along the line III-III in Fig. 1.

Fig. 4 shows a detail Z in Figure 1 in an enlarged Dar position;

Fig. 5 is a schematic representation of a machine station for receiving the pallet.

In Fig. 1, a clamping device for a workpiece 1 is shown in plan view. A pallet 2 is formed with rods 3 running parallel to one another, which are connected at one end by a strut 4 and at the other end are received in a stationary clamping jaw 5 . On the rods 3 , a clamping jaw 7 is slidably mounted, which, like the clamping jaw 5 , has holding means 8 on its side facing the workpiece 1 , via which it engages the workpiece 1 .

As can be clearly seen in FIG. 2, the holding means 8 are provided with a first leg 10 , which extends perpendicular to the circumferential direction of the workpiece 1 , and with a second leg 11 perpendicular thereto. You are placed with the latter so on the respective Spannbac ken 5 , 7 that the side facing away from the workpiece 1 of the first leg 10 on the workpiece 1 facing side of the jaw 5 , 7 comes to rest. Since by the two legs 10 and 11, the contact surface on the Spannbac ken 5, 7 is large enough to dropping of the holding means to prevent 8, this need not bake 5, 7 to be fixed on the instep.

The leg 10 of the retaining means 8 is at its side facing the workpiece 1 side facing a bend 12 is formed perpendicular to the circumferential direction of the workpiece 1 is convex, wherein the location of towards the jaws 5, 7 largest supernatant in the direction towards the workpiece 1 is preferably in the Center region of the leg 10 is formed. At this central area, the workpiece 1 comes into contact with the holding means 8 when it is clamped in the pallet 2 , the line of contact between the holding means 8 and the workpiece 1 extending substantially in the horizontal direction.

In the leg 11 of the holding means 8 , perpendicular to its direction of extension, threaded bores 13 are formed, in each of which a grub screw 14 engages. At least one of them, if the holding means 8 is held in a force-fitting manner between the latter and the clamping jaws 5 , 7 when the workpiece is clamped, is brought into contact with the latter, so that the clamping jaw is effective as a support bearing for the threaded pin 14 . As soon as this acts upon screwing into the threaded hole 13 on the clamping jaws 5 , 7 , a continued rotation in the direction of rotation since then causes the holding means 8 to be lifted off the clamping jaws 5 , 7 and the workpiece 1 , which is still held non-positively, on this Side of the same lifts, while it does not change its vertical position on its remaining one clamping sides, but only adjusts itself to the new vertical position of the raised holding means 8 by a compensating "rolling movement" on the contact lines of the holding means 8 . Since the horizontal alignment of the workpiece 1 in the pallet 2 can consequently take place via the threaded pins 14 , these act as adjusting means 15 .

The pallet 2 is placed for clamping the workpiece on one end on a ground cuboid 17 ( FIG. 1) and on the other end on a clamping table 18 , as it is both in a pre-setting station 19 shown schematically in FIG. 5 and in a machining station 20 also shown schematically is arranged. The clamping tables 18 each have recesses 22 which have a recess 23 at their pallet-side ends ( FIG. 3) and a threaded bore 24 at their opposite ends. The recesses 22 are formed at predetermined distances from a hole assigned to the zero point position 25 of each clamping table 18 .

The connection of the pallet 2 with the clamping table 18 is produced by fastening elements 27 , which can be inserted into a recess 28 ( FIGS. 3, 4) of the pallet 2 and into the recess 23 of the associated recess 22 and each have a screw 29 , the tion 24 of the recess 22 can be screwed into the threaded bore. The recesses 28 in the pallet 2 are each formed with conical segments 49 ( Fig. 4) which are interrupted by flat bevels 50 un. These are preferably offset at an angle of 90 degrees, and act as abutment ribs 51 for a conical housing part 30 of the respective Befestigungsele mentes 27, wherein the angle at which the outer wall of the recess line 28 with respect to the abutment ribs 51 on the centers of runs of the fastener 27 , the angle speaks ent that exists between this center line and the conical housing part 30 . This angle is preferably in the range of 10 degrees to 20 degrees, but assumes 12 degrees, in view of a compact design of the Verbindungsele element 27 , an optimum.

The housing 32 of the fastener 27 is, as shown in FIG. 3 in the right half of the figure, formed as a hollow body and takes on a sleeve 33 which surrounds the already mentioned screw 29 , which when screwed into the threaded bore 24 with its screw head 34th can be brought into contact with the upper end of the sleeve 33 . The opposite end of the sleeve 33 is provided with a conical punch 35 which can be brought into contact with a conical section 37 of the housing 32 . The angle at which this section 37 runs relative to the central axis of the fastening element 27 corresponds to that of the punch 35 with respect to the said central axis and lies within an angular range of 12 degrees to 30 degrees, but takes for reasons that will be discussed below , an optimum at 16 degrees.

The section 37 is provided in a housing projection 38 of the fastening supply element 27 , which is formed along its circumference with a plurality of tongues 39 , at the free ends of which a screw 29 in the housing 32 securing ring 40 rests. The housing projection 38 tapers slightly, starting from the conical housing part 30 , for easier insertion into the recess 23 of the recess 22 of the clamping table 18 , which is cylindrical.

To fasten the pallet 2 to the clamping table 18 , in contrast, the pallet 2 is oriented such that its recesses 28 are aligned with one recess 22 of the clamping table 18 . Subsequently, in each of these pairs of recesses 28 , 22, a fastener 27 is inserted and tightened by screwing the screw 29 so that the conical housing part 30 non-positively against the abutment ribs 51 on the conical outer wall of the recess 28 of the pallet 2 and the sleeve se 33 by the screw head 34 is pressed down so that the punch 35 on the conical portion 37 of the Ge housing approach 38 presses the tongues 39 radially outward until they come into positive engagement with the outer wall of the recess 23 of the recess 22 . The stamp 35 is therefore effective as a wedge 41 , which is movable relative to the housing 32 of the fastening element 27 . The deflection angle of the gene 39 in this expansion of the housing extension 38 is limited by appropriate dimensioning of the recess 23 so far that the expansion of the housing extension 38 remains in the elastic range and the tongues 39 can spring back into their starting position when the load is released. By the aforementioned, for the punch 35 optimal angle of 16 degrees, when the sleeve 33 is raised by loosening the screw 29 like that, the conical section 37 of the housing 38 is immediately released. In the event of deviations from the optimal angle, however, either the self-locking of the punch 35 on the conical section 37 or, in the opposite direction of deviation, the wedge effect of the punch 35 is not sufficient for an expansion of the housing extension 38 .

Fastened by the fastening elements 27 equally on the clamping table 18 and centered relative to this, the pallet is prepared so far that the workpiece 1 can be inserted and clamped by the clamping jaw 7 as shown in FIG. 1 is pushed to the left until the holding means 8 with this in annex. In this position, the clamping jaw 7 is fixed by a threaded pin 70 .

The position data of the workpiece 1 in the pallet 2 are recorded by a measuring device 43 provided at the pre-setting station 19 ( FIG. 5), designed in the usual way and therefore not described in detail, and fed to a controller 44 of the processing station 20 , which is a computing unit 59 for Correction of the machining program stored in a memory 60 to the current position of the workpiece, so that it can be machined in the correct position. In addition, the workpiece 1 , with the aid of the measuring device 43 , is aligned horizontally in the pallet 2 via the vertical position of the holding means 8 .

The pallet 2 prepared in this way, after loosening the fastening elements 27 , is taken from the clamping table 18 of the Voreinrichtsta tion 19 and placed on the clamping table 18 with the same construction of the processing station 20 , in such a way that the distance between the zero point position 25 of this clamping table 18 the recesses 22 , with which the pallet 2 is to be connected via the fastening elements 27 , exactly match the situation on the clamping table 18 of the pre-setting station 19 . By jamming the pallet 2 with the clamping table 18 of the processing station 20 through the fastening elements 27 , even minimal errors that could be caused by play are excluded. The workpiece can then be processed in the correct position on the processing station 20 using its position data that has already been entered.

Claims (17)

1. Clamping device for a workpiece, comprising a pallet with clamping jaws for the workpiece, holding means ( 8 ) engaging between the clamping jaws ( 5 , 7 ) and the workpiece ( 1 ), which by means of adjusting means ( 15 ) relative to the clamping jaws ( 5 , 7 ) for the horizontal alignment of the workpiece ( 1 ) are vertically displaceable, fastening elements ( 27 ) for connecting to a clamping table ( 18 ) of a processing station ( 20 ), which fastening elements ( 27 ) via a conical housing part ( 30 ) in recesses ( 28 ) of the pallet ( 2 ) and can be clamped in a recesses ( 22 ) of the clamping table ( 18 ) by a housing extension ( 38 ) that is elastically expandable relative to the conical housing part ( 30 ), the pallet ( 2 ) with one to the clamping table ( 18 ) The processing station ( 20 ) of the same design as the clamping table ( 18 ) of a pre-setting station ( 19 ) can be connected to a measuring device ( 43 ) for determining the position data of the workpiece ( 1 ) is provided relative to a predeterminable zero point position of the clamping table ( 18 ) and the horizontal alignment position of the workpiece ( 1 ) and the position data when the pallet ( 2 ) is changed to the clamping table ( 18 ) of the processing station ( 20 ) the latter are transferable for correct machining of the workpiece ( 1 ). 2. Clamping device according to claim 1, characterized in that the holding means ( 8 ) engage in the horizontal direction on the outer edge of the workpiece ( 1 ). 3. Clamping device according to claim 1 or 2, characterized in that the holding means ( 8 ) on their workpiece ( 1 ) facing sides are each formed with a curvature ( 12 ) in the extent of the workpiece ( 1 ). 4. Clamping device according to claim 3, characterized in that the holding means ( 8 ) via convexly formed curvatures ( 12 ) for holding the workpiece add ver, the curvatures ( 12 ) in the direction of extension perpendicular to the workpiece circumference in the central region opposite the largest projection form the respective jaws ( 5 , 7 ). 5. Clamping device according to claim 1, characterized in that the holding means ( 8 ) in each case one between a clamping jaw ( 5 , 7 ) of the pallet ( 2 ) and the work piece ( 1 ) engaging first leg ( 10 ) and an angled thereto have the second leg ( 11 ) facing away from the clamping point, which comes to rest on the upper side of the clamping jaw ( 5 , 7 ). 6. Clamping device according to claim 1, characterized in that the holding means ( 8 ) are each provided with at least one adjusting means ( 15 ), the pallet-side end for support on the pallet ( 2 ) with vertical displacement of the holding means ( 8 ) on the clamping jaw ( 5 , 7 ) can be placed. 7. Clamping device according to claim 6, characterized in that the adjusting means ( 15 ) is formed by a threaded pin ( 14 ) guided in a threaded bore ( 13 ) of the holding means ( 8 ). 8. Clamping device according to claim 1, characterized in that the fastening elements ( 27 ) within their housing ( 32 ) each have a screw ( 29 ) which engages in a threaded bore ( 24 ) of the recess ( 22 ) of the clamping table ( 18 ) and due to the depth of penetration of the conical housing part ( 30 ) in the recess ( 28 ) of the pallet ( 2 ) on the one hand and a displacement of a sleeve ( 33 ) comprising a wedge ( 41 ) relative to the housing extension ( 38 ) for the elastic widening thereof the recess ( 22 ) of the clamping table ( 18 ) on the other hand can be achieved. 9. Clamping device according to claim 1, characterized in that the recesses ( 28 ) provided for the fastening elements ( 27 ) in the pallet ( 2 ) are designed as through-openings with a conical outer wall, the angle of which with respect to the central axis is that of the conical housing part ( 30 ) of the fastening element ( 27 ) corresponds to its central axis, where the diameter of the recesses ( 28 ) are selected so that the conical housing parts ( 30 ) of the fastening elements ( 27 ) can be received without play. 10. Clamping device according to claim 9, characterized in that the conical housing part ( 30 ) of each fastening element ( 27 ) as well as the outer wall of the recesses ( 28 ) of the pallet ( 2 ) with respect to their central axis each extend at an angle, preferably between 10 ° and 20 °. 11. Clamping device according to claim 10, characterized in that the conical outer walls of the recesses ( 28 ) in the pallet ( 2 ) are interrupted by flat bevels ( 50 ) which are at the same angle to the center axes of these recesses ( 28 ) as the ko African outer walls and serve as abutment ribs ( 51 ) for the conical housing part ( 30 ) of the fastening elements ( 27 ). 12. Clamping device according to claim 11, characterized in that the abutment ribs ( 51 ) are offset from one another, preferably by 90 °. 13. Clamping device according to claim 1, characterized in that the housing extension ( 38 ) of the fastening elements ( 27 ) has a plurality of axially extending tongues ( 39 ) distributed over the circumference. 14. Clamping device according to claim 1 or 13, characterized in that the housing extension ( 38 ), starting from its connection to the conical housing part ( 30 ) of the fastening element ( 27 ), tapers at a negligibly small angle. 15. Clamping device according to claim 8 and 13, characterized in that the screw ( 29 ) is enclosed by a sleeve ( 33 ), at the end of the housing insert ( 38 ) of each fastening element ( 27 ) facing the end of the screw head ( 34 ) can be brought into contact and the opposite end of which has a conical punch ( 35 ) which acts as a wedge and extends radially inside the tongues ( 39 ) of the elastically expandable housing attachment ( 38 ) and can be brought into contact with it. 16. Clamping device according to claim 15, characterized in that the housing extension ( 38 ) is formed on its inner side in the extension region of the plunger ( 35 ) with a conical section ( 37 ) which, referred to the central axis of the fastening element ( 27 ) , runs at the same angle as the stamp ( 35 ). 17. Clamping device according to claim 16, characterized in that the angle of the stamp ( 35 ) of the sleeve ( 33 ) and the conical section ( 37 ) of the Ge housing approach ( 38 ) with respect to the central axis of the fastening element ( 27 ) preferably within a range of 12th Degrees to 30 degrees.