SK9332002A3 - Clamping device for the position-defined clamping of a tool or workpiece - Google Patents

Abstract

A clamping device for the position-defined clamping of a tool or workpiece comprising a tool or workpiece support as a demountable holder (1) and a fixedly arranged clamping element (2). The demountable holder (1) is provided with grooves (13) that are designed to match, for the purpose of precision alignment and fixing the position in the direction X and/or Y, with two alignment plugs (26) provided on the fixedly arranged clamping element (2). The fixed clamping element (2) having the stop surfaces (24) and the demountable holder (1) comprising the abutting surfaces (10a), which abut against the stop surfaces (24) after the achieved clamping, and thereby they define cross position of both clamping elements (1,2) in the Z direction. The latter is further fitted with a clamping pin (21) which ensures that both clamping elements (1, 2) are reciprocally secured. The clamping pin/ clamping pins (21) is/are placed on the fixedly arranged clamping element (2). The demountable holder (1) is equipped with a support member (11) with an end bearing surface (12) for protecting the parts essential for the fine centring, which support member extends beyond said fine centring parts on demountable holder (1).

Description

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a clamping device for position-defined clamping of a tool or workpiece with a fixed clamping element and a tool or workpiece carrier as a detachable clamping element on the clamping element, wherein one of the two clamping elements is provided for positioning. positions in the X and / or Y directions intended to interact with centering pins arranged on the second clamping element.

BACKGROUND OF THE INVENTION

EP 0 255 042 B1 discloses a tool or workpiece clamping device for a machine tool comprising a chuck and a holder belonging to the tool or workpiece to be clamped. The chuck has columns and bars protruding from the front, the bars protruding over the columns and provided with abutment surfaces for aligning the tool or workpiece. The holder has a planar surface for abutting the posts in which grooves are formed to align the n chuck of the chuck, wherein the grooves are provided with resilient flaps designed to abut on the bars. The clamping bolt is used for clamping the tool holder or workpiece.

In order to allow the holder to be locked when it is placed away from the machine tool and to limit damage to the clamping bolt, the clamping bolt must be removed before the tool holder is put down. After removal of the clamping bolt, the holder can be parked on its planar surface. However, there is a risk of mechanical damage to the flexible flaps and / or contamination of the grooves. This danger also arises from the lateral removal of the holder, and it does not matter whether the clamping bolt is removed in advance or not.

It goes without saying that such a clamping device should be handled with care since the holders and spring flaps important for fine centering are very exposed. Moreover, this clamping device is not suitable for large and heavy tools, since experience has shown that large and heavy devices cannot be treated with the same care as small and light clamping devices.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The object of the invention is to improve the clamping device of the aforementioned type so as to be more robust and less sensitive to handling while maintaining a high degree of alignment of the two elements.

this In essence, the clamping device for the positionally defined tool or workpiece clamping, with fixed clamping element and fixed on it carrier tool or workpiece as removable clamping element, with one for positioning

on one side of the two clamping elements provided with grooves which are intended to cooperate with the centering pins arranged on the second clamping element for positioning in the X and / or Y direction, and on the other hand, one of the two clamping elements has protruding projecting surfaces and the other an element of planar bearing surfaces, the latter of which, after reaching the solid surfaces, determine the relative position of the two clamping elements in the Z direction, wherein at least one clamping bolt is arranged for interlocking the two clamping elements, the clamping bolt (s) being / are arranged on a fixed clamping element, and wherein the tool or workpiece carrier has a support element provided with an end abutment surface which overlaps the essential elements over the clamping element arranged and finely centered.

By arranging the clamping bolt on the fixed clamping element, it is ensured that the tool or workpiece carrier does not contain any substantially protruding parts, thereby facilitating the removal of such a clamping element.

The arrangement of the support element on the tool or workpiece carrier, wherein the support element protrudes over portions of the clamping element substantially provided with an end support robust for fine centering of the surface, leads to a clamping element with which formation can be manipulated sensitivity, simple and inclined excessively very sensitive to contamination and exposure, are protected by elements that are significantly reduced to mechanical. In addition, the mounting element and the risk of damage are made possible by a support element stable on the support.

In a preferred embodiment of the clamping element, it is proposed to form the inner side of the support element so that it corresponds to the outer contour of the fixed clamping element, the support of the respective clamping centering being more prominent

By this measure it is achieved that, in the locked state, the element of the element exceeds substantially by a value over the elements of the superficial elevation of the surfaces of the fixed fixture.

for both elements, portions of both elements essential for fine centering are protected.

In this way, the risk of contamination or damage to parts of the two fine-centering elements can be permanently reduced when machining workpieces, such as drilling, milling, turning or electro-erosion machining.

In a further preferred embodiment of the invention, it is proposed to provide the support element on the inner side of the region extending beyond the planar bearing surfaces with a sealing ring which, when the two elements are joined, engages outside the fixed clamping element. The clamping device formed in this way is then not sensitive to dust or water.

Another object of the present invention is to provide a device which is particularly suitable for positionally defined clamping of large and heavy tools and workpieces.

To solve this problem, a device is provided which is provided with a plurality of clamping devices according to the invention. The device consists of a workpiece clamping device on which a plurality of clamping elements are arranged to cooperate with a number of fixedly arranged centering pins of the clamping devices with corresponding elements. The grooves a together determine the definitive position of the workpiece clamping devices in both the X and Y directions as well as the angular position on the workpiece

With such a device, very large and heavy workpieces, which must often be handled by crane, can be quickly and effortlessly transported to the machining point and clamped there. After machining, the workpiece clamping device can be parked in virtually any location, such as the floor, without taking special precautions, since the workpiece clamping device relies upon the supporting elements of the corresponding clamping elements and the damage and contamination of the fine-grained elements. centering can thus practically be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below with reference to the drawings, in which:

Fig. 1 is a cross-sectional view of a first example of a clamping device comprising a fixed clamping element and a tool or workpiece support;

Fig. 2 perspective view of Fig. 1; view on the firm clamping element Fig. 3 perspective view on the the first one variant support of the tool or workpiece of FIG . 1;

Fig. 4 is a perspective view of a second variant of the tool or workpiece carrier of FIG.

5 is a schematic side view of an alternative embodiment of the clamping device;

Fig. 6 is a schematic side view of another alternative embodiment of the clamping device;

Fig. 7 is a perspective view of another alternative embodiment of a tool or workpiece;

Fig. 8 is a perspective view of an embodiment of a fixed fixture intended to cooperate with the tool or workpiece carrier of FIG. 7;

9 shows a plan view of a device for positionally defined workpiece clamping; and

10 is a side view of the device of FIG.

DETAILED DESCRIPTION OF THE INVENTION

For the sake of simplicity, in the following, only the term "carrier" is used for the tool or workpiece carrier, and only the term "clamping element" is used for a fixed clamping element.

Fig. 1 shows a cross-section of a first embodiment of a clamping device comprising a fixed clamping element and a support, wherein Figs. 3 show a perspective view of the clamping element 2 and the carrier 1, wherein the carrier 1 is in partial section. As shown in FIG. 1, the carrier 1 together with the clamping element 2 forms a clamping device. Normally, the carrier 1 belongs to the tool or workpiece to be clamped, while the clamping element 2 is fixedly fixed, for example, to the machine table of the machine tool.

Nosič _! The support element 11 protrudes on the underside 10A over the base body 10 and is provided with an end support surface 12. On the upper side, the support element 11 terminates flush with the planar surface of the base body 10.

A central bore 18 is formed in the base body 10 and is bounded at the bottom by an annular insert 15. This annular insert 15 has a tapered centering surface 15A. The liner 15 is preferably fastened to the base body 10 in an interchangeable manner and is fixed, for example, by means of screws (not shown). Inside the central bore 18 a recess 16 is provided to engage the clamping balls of the clamping element. On the planar underside 10A of the base body 10, notches are formed in the form of grooves 13 which, in a known manner, are intended to cooperate with the centering pins arranged on the clamping element. According to an embodiment, two mutually opposite or four eccentric and angularly offset grooves 13 are arranged. A notch 14 is arranged behind each groove 13, the detailed meaning of which will be explained hereinafter.

A circular recess is formed on the underside 10A of the base body 10

17, which adjoins the inner side of the support element

11. Grooves together with planar underside

10A of the base body 10 represent carrier elements

1, essential for fine centering, while a coarse insert 15 is provided for coarse centering. The elements 10A, 13 essential for fine centering are protected from damage by a support element 11 projecting downward.

The clamping element 2 comprises a base body 20 on which the clamping bolt 21 is mounted. The free end surface 21A of the clamping bolt 21 is formed as a centering surface such that it is chamfered to semicircular and extends at least over a third of the cross-section of the clamping base bolt 21. 20, four and two centering drawings are shown with pins 26, only three, with the upper sides 20A of the distinctive surface 24 as shown on the surfaces 24. V holes 25.

Wed.

By means of these vents, out of these orifices 24, outwardly, four pressure vents can be discharged through which the abutment surfaces are cleaned.

The centering pins 26 can be fastened in the grooves 23 of the base body 20 by means of screws and have veneers 27 formed as bearing surfaces. The centering pins 26, together with the striking surfaces 24, are essential elements for fine centering the clamping element 2, while the free end surfaces 21A of the clamping bolt 21 are intended for coarse centering. For clamping the carrier and the clamping element together, the clamping bolt 21 has a series of clamping balls 22 when clamped onto the wall of the corresponding recess 16 of the carrier 7 (FIG. 3).

Fig. 1 shows a cross-section of the clamping element 2 and the centering element 11 during the clamping process. The connection of the two elements 1,2 is facilitated by a coarse centering means consisting of an annular insert 15 and a tapered end surface 21A of the clamping bolt 21. The annular insert 15 is preferably formed of a material softer than the clamping bolt 21, thereby reducing bolt damage during centering.

the annular insert 15 arrives

Suitable materials are, for example, brass and bronze, but also many plastics.

The coarse centering is followed by a fine centering in that the centering pins 26 are aligned on the grooves 13 in a known manner. If the centering pins 26 are flush with the grooves 13, the centering pins 26 engage the grooves 13 substantially without force action. Thus, the relative positioning of the two elements 1 and 2 in the X and Y directions as well as the angular position is completed.

Now the two elements 1 and 2 are tightened relative to each other by engaging the clamping balls 22 on the wall of the recess 16 of the carrier 1. Inside the clamping bolt 21, there is a sliding piston 3.0 which pushes the clamping balls 22 outwardly because it is elastically loaded in the direction of the free end faces of the clamping bolt 21. The piston 30 can be pneumatically moved downwardly against the spring bias so that the clamping balls 22 are relieved and the two elements 1, 2 can be separated again.

In the rest position shown here, the piston 30 remains in the up position and pushes the clamping balls 22 into the recess 16, whereby the two elements 12, 2 are wedged to each other. Pressurized air is blown into the pressure chamber 31 to move the piston 30 and thereby release the clamping balls 22. It is also possible to provide a clamping element such that the piston 30 can be pneumatically counter-moved. This could be done or in addition to or instead of the spring bias. Also in this way both elements can be pneumatically clamped and locked.

In order to bring the support 1 to the desired position in the Z direction with respect to the clamping element 2, the support 1 is displaced so long in the Z direction against the elastic force of the resilient element formed by the notch 14 of the groove 13 during the clamping process. 4, with its planar underside 10A, engages the surface 24 of the clamping element 2 (FIGS. 2 and 3).

By supporting the support element over the elements 10A,

13, 14 of the carrier 1 (FIG. 1) essential for a fine centering of more than the value of the cantilever elevation is the upper side of the clamping element 2 the supporting element

Through sealing grip.

ring

24

32, located on the inside of all of the element portions 10A, 13, essential to reliably

14, 21, impeccable support

22, 24, the centering function protected from the element 11 are both impurities entering and clamping.

Instead of the sealing ring arrangement shown in FIG. 1, the support element may be provided on the inside with a bevelled end surface in which a groove in which the sealing ring is located is formed at a certain angle to the bearing surfaces. Advantageously, the fixed clamping element in the region corresponding to the sealing ring is provided with a continuous edge on which the sealing ring can abut. By this design, the forces acting on the carrier by means of the sealing ring can be kept small, so that the centering process is not affected.

Fig. 4 shows a perspective view of a second embodiment of the carrier IB in partial section. Instead of a notch arranged behind the groove, in this carrier IB, two resilient flaps 34 are formed behind the groove 13B, which are formed by slits 35 extending parallel to the planar underside of the carrier. The flaps 34 thus formed achieve the same effect as the notches so that, after gentle centering, the abutment surfaces of the clamping element against the abutment surfaces of the clamping element are achieved against the abutment surfaces of the support.

Fig. 5 shows a schematic side view of another alternative embodiment of the carrier 1C provided with a resilient washer 37. The clamping element 2C here corresponds to the clamping element as described above. The spring washer 37 is disposed on the underside of the carrier 1C and replaces the notch 14 of the groove 13 of FIG. 1, since in the present case it assumes the spring function. In the region of the grooves 13C, the spring washer is formed reinforced.

In order to allow the deflection of the spring washer 37 in the region of the grooves 13C, the base body of the carrier in the region of the grooves 13C is provided with a recess 39 that is deeper than the elevation of the spring washer 37 due to the reinforcement. Thus, a gap 38 remains between the resilient washer 37 and the recess 39 to allow some bending of the resilient washer 37. In addition to the grooves, openings may also be provided in the resilient washer.

Fig. 6 shows a schematic side view of an alternative embodiment of the clamping element 2D. In this case, instead of the grooves that are notched or arranged on the spring washer, the centering pins 40 are resiliently arranged. For this purpose, a recess 41 is arranged behind the centering pin 40. Instead of the recesses 41, the centering pins 40 could naturally also be resiliently supported. , for example by being arranged on a resilient support. In the resilient arrangement of the centering pins 40, the corresponding grooves could be fixed or embedded in a fixed region of the centering element ID.

Fig. 7 and 8 show a perspective view of another alternative embodiment of a clamping device which also consists of a workpiece carrier 44 and a fixed clamping element 45. This clamping device is particularly suitable for large and heavy workpieces. In order to exert a high and uniformly acting clamping force, the fixed clamping element 45 is provided with four clamping bolts 46, surrounded by a striking surface 51. These striking surfaces 51 are several millimeters higher than the surface of the clamping element 65. A centering pin 47 is arranged between the two clamping bolts 46. Each of the four centering pins 47 is received in a recess formed in the planar surface of the clamping element.

The carrier 44 has four circularly formed bearing surfaces 52, in the center of which an aperture 53 corresponding to the clamping bolt is arranged. The fine centering grooves 49 are formed in resilient elements

48, which are embedded in recesses 50 in the carrier 60. The elastic elements 48 thus formed are capable of absorbing high shear forces.

The illustrated arrangement of the fine centering elements of the clamping device, namely the resilient elements 48 with grooves 49 and centering pins 47, gives the definitive position of the carrier 44 in both the X and Y directions as well as the angular position with respect to the given Z axis.

For the sake of clarity, three variations of the support elements are shown on the support 44. The first variant consists in an outer circular strip 54, which corresponds to the outer contour of the clamping element 45. The height of the support element 54 is selected such that the elements 48,49,52, essential for fine centering, protrude by more than the elevation of the protruding solid surfaces. 51 of the clamping element 45.

A second variant consists in arranging the strip 56 on the underside of the carrier 44, in which case the height of the strip 56 must be chosen such that the elements 48, 49, 52, essential for fine centering, project less than the elevation of the projecting areas 54 Thus, it is ensured that the abutment surfaces 52 abut the defined surfaces 51 in a determined manner.

Finally, posts 55 located in the corners can also be provided as supporting elements. Also in this case, the height of the posts 55 must be chosen such that the elements 48, 49, 52, essential for fine centering, protrude less than the value of the elevation of the protruding areas 51 of the clamping element 45.

Instead of the four clamping bolts 66 shown, a plurality of these clamping bolts, for example six, can naturally also be provided. It is also possible to increase the number of centering pins 47 together with the corresponding number of grooves 49 in accordance with the requirements.

Fig. 9 shows a schematic plan view of a workpiece clamping apparatus, and FIG. 10 shows a schematic side view of the apparatus. The device comprises four clamping devices 3 and a workpiece clamping device 4. The workpiece clamping device 4 consists of a circular plate 5y on the underside of which four carriers 1 are mounted, which are arranged symmetrically to the central axis 6 of the plate 5. A workpiece to be machined (not shown) is mounted on the plate 5, and any other workpiece clamping device, such as a clamping frame, may be provided in place of the plate.

The four clamping elements 2 of the clamping devices 3 are rigidly arranged, for example on the machine table of the machine tool. Each of the four clamping devices 2 is provided with two centering pins and two corresponding grooves, and these centering elements together determine the definitive position of the workpiece clamping device 6 in both the X and Y directions and also angularly with respect to the Z axis.

Instead of the circular workpiece clamping devices 4 shown here, of course, any other embodiments of these clamping devices, for example rectangular, are also contemplated. In rectangular workpiece clamping devices, it is advantageous to provide one of the clamping devices with four grooves and centering pins. Such a clamping device is a given position of the workpiece clamping device in the X and Y directions and is determined by the Z axis.

In addition, at least one additional second clamping device must be arranged at a distance from the first clamping device, which determines the angular position of the clamping device on the workpiece with respect to the Z axis. For this, a clamping device comprising two grooves and two centering pins is provided. length changes of workpiece clamping device in one direction. It also allows high positioning accuracy of the workpiece to be clamped under unfavorable conditions, for example under the influence of temperature-dependent dimensional changes to the workpiece.

Instead of the clamping devices described above, the device can naturally also be provided with the clamping devices according to FIGS. 7 and 8.

The advantage of equipping the workpiece clamping device of the invention is in particular not sensitive to the clamping devices according to the fact that it is very robust to handle.

When such a workpiece clamping device is not attached to the workpiece, the carrier elements essential for fine centering are in no way negatively affected through the elements because the fine centering support element overhangs and the carrier essential and therefore only the supporting surface comes into contact with the support.

PATENT

Claims (22)

Clamping device for positionally defined clamping of a tool or workpiece, with a fixed clamping element (2,45) and a fixed clamping element (1,44) of the tool or workpiece thereon as a removable clamping element, one of the two for positioning clamping elements (1,44) provided with grooves (13,49) which are intended to cooperate with centering pins (26,47) arranged on the second clamping element (2,45) for positioning in the X and / or Y direction, and wherein, on the other hand, one of the two clamping elements (2,45) has protruding surfaces (24,51) and the other clamping element (1,44) has planar bearing surfaces (10A, 52), the latter of which abut after reaching clamping on the areas (24,51) and thereby determine mutual location of both clamping elements (1.2, -44.45) in Z direction while is a arranged at least one clamping bolt (46; 46) on the mutual blocking of both clamping elements (1,2, -44,45), wherein the clamping bolt (s) (21,46) is / are arranged on the fixed clamping element (2; 45), and wherein the tool or workpiece support (1,44) has a support element (12.54; 55.56) provided with an end abutment surface (12; 58) that extends over the essential elements (10A, 13.14; 48.49.52) arranged over this clamping element (1.44) and finely centered ). Clamping device according to claim 1, characterized in that the inner side of the support element (11) corresponds to the outer contour of the fixed clamping element (2) and that the support element (11) extends over the elements (10A, 13,14). ) of a tool or workpiece carrier (1), essential for fine centering, by more than the value of the elevation of the protruding surfaces (24) of the fixed clamping element (2). Clamping device according to claim 1 or 2, characterized in that both the tool or workpiece carrier (1) and the fixed clamping element (2) are substantially cylindrical, the support element (11) encircling the fixed clamping element circularly. (2) such that the inner diameter of the support element (11) corresponds at least approximately to the outer diameter of the fixed clamping element (2). Clamping device according to claim 2 or 1, characterized in that the support element (11) is provided on the inside with a sealing ring (32) which, when the two clamping elements (1, 2) are connected, engages outside the fixed clamping element (2). ). 5th Tie device according to claim 4, v y z on the hear c e sa by supporting the support element on the the inside page bevelled end face, which is a provided at an angle to the bearing surfaces inclined a groove in which the sealing ring is received. Clamping device according to one of the preceding claims, characterized in that the tool or workpiece carrier (1) is provided with a central bore (18) for clamping the clamping bolt (21) of the fixed clamping element (2), and that the clamping bolt (21) together with the bore (18) of the tool or workpiece carrier (1) is formed as a coarse centering element in that the clamping bolt (21) is provided in the end region with a beveled or semi-circular centering surface (21A) to cooperate with the circular insert (15), delimiting on the underside a central bore of the tool or workpiece carrier (1). Clamping device according to claim 6, characterized in that the annular insert (15) delimiting the bore (18) of the tool carrier (1) or the workpiece has a chamfered center surface (15A), the annular insert (15) being fixed. in an interchangeable manner and consists of a material that is softer than the clamping bolt (21). Clamping device according to claim 6 or 7, characterized in that the centering surface (21A) of the clamping bolt (21) extends over at least one third of its free end surface. Clamping device according to one of the preceding claims, characterized in that one or more slits (14), which is / are / are / are arranged behind and / or sideways from the groove (13) of the tool or workpiece carrier (1). formed in such a way that the centering pin (27) engaging the groove (13) in the Z-direction clamping faces the resilient force upon which the planar abutment surfaces (10A) of the first clamping element (1) abut against the distinct surfaces (24) of the second clamping element (2). Clamping device according to one of Claims 1 to 8, characterized in that one or more notches (41) are / are provided behind and / or on the side of the centering pin (41). such that the centering pin (27) engaging the groove (13) when clamping in the Z direction is opposed to the resilient sleeve, after which the planar bearing surfaces (10A) of the first element (1) bear on the distinctive surfaces (24) of the second element (2) . Clamping device according to one of Claims 1 to 8, characterized in that it comprises a spring washer (37) in which the grooves (13c) are embedded. Clamping device according to one of Claims 1 to 8, characterized in that the centering pin is arranged on a spring washer. Clamping device according to one of the preceding claims, characterized in that the tool or workpiece carrier (1) is provided with slotted recess side on the support element (17), (11) · follow - up the inside 14. Clamping device according to one from previous claims, characterized ú c i sa in that the clamping bolt (21) comprises a plurality of clamping balls (22) which, when clamped, abut against the wall of the corresponding recess (16) of the tool or workpiece carrier (1). Clamping device according to claim 14, characterized in that the clamping balls (22) are pushed outwardly by the resiliently loaded and pushed-in control element (30) displaceably disposed within the clamping bolt (21), the resiliently loaded the actuating element (30) can be pneumatically displaced against the resilient bias so that the clamping balls (22) are relieved. 16th 17th Clamping device according to claim 1, characterized in that the tool or workpiece carrier (1) comprises at least four clamping bolts (46) as well as at least four centering pins (47) and a fixed clamping element (45) such a number of grooves (49) ), which corresponds to the number of centering pins (47), wherein the grooves (49) and centering pins (47) of the clamping device together determine the definitive position of the clamping element (44) in both the X and Y directions as well as the angular position relative to the axis FROM. Clamping device according to claim 16, characterized in that the support element is designed as a runner (54), the inner side of which corresponds to the outer contour of the fixed clamping element (45), the support element (54) extending over the elements (48). 49.52) of the second clamping element (44), essential for fine centering, by more than the value of the elevation of the protruding areas (51) of the first clamping element (45). 18th confesses 19th tools Clamping device according to claim 16, characterized in that at least one support exceeds / exceeds the tool or centering on the underside of the workpiece support (44) or the workpiece element by (48,49,52) workpiece elements which or which (48,49,52) of the substantial support for less than the value of the elevation of the protruding solid surfaces of the first clamping element (51) Clamping device according to one of Claims 16 to 18, characterized in that it comprises four clamping bolts (-46), between two (45). 20th (47). a centering pin is provided by the bolts (46) Clamping device according to one of Claims 16 to 19, characterized in that it comprises a discrete elastic element (48) in which the recessed grooves (49) are designed for fine centering, the elastic elements (48) being fitted in the recess (50). in a tool or workpiece carrier (44). 21st 22nd Clamping device according to one of claims 16 to 20, characterized in that the centering pins (47) for fine centering are designed as discrete elements and are mounted in recesses of the fixed clamping element (45). A device for position-defined clamping of workpieces provided with a plurality of clamping devices (3) according to one or more of Claims 1 to 21, with a workpiece clamping device (4) in which a plurality of clamping elements (1) are arranged to cooperate with a corresponding number of fixed clamping elements (2), wherein the grooves and centering pins of the clamping devices (3) determine the common definitive position of the clamping device (4) on the workpiece both in the X and Y directions as well as the angular position with respect to the Z axis. Apparatus according to claim 22, characterized in that it comprises a first clamping device comprising a tool or workpiece clamping element and a fixed clamping element, wherein the clamping device is provided with four grooves and centering pins which together determine the position of the fine centering elements the clamping 23rd a workpiece device in the X and Y directions and thus a Z axis position, and wherein at least one additional clamping device is provided at a distance from the first clamping device, which is provided with two grooves and two centering pins which fine centering elements determine the position of the workpiece clamping device only as regards the angular position on the Z axis. 24th Device according to claim 22, characterized in that the workpiece clamping device (4) is circular and is provided with four clamping devices (3) which are further provided with two grooves and two centering pins, wherein the clamping elements (1) ) for the tool or workpiece are arranged on the workpiece clamping device (4) symmetrically on the central axis (6) and offset angularly from one another.