Clamp device

Abstract

To accept or compensate tolerance or dimension changes of clamp elements on clamp means in an X-Y plane or work-piece carriers that are fastened by the clamp elements, without providing an elastic centering element.SOLUTION: Clamp means (1) has a clamp module (2) provided with a clamp member, where the clamp module (2) can be fixed onto a clamp base by a fixing element (3). The fixing element (3) is configured so that the clamp module (2) is fixed in a floating manner on the clamp base in an X-Y plane. The clamp module (2) being fixed by fixing element (3) can be displaced with respect to the fixing element (3) in the X-Y plane but cannot be displaced in a Z-direction. The fixing element (3) is provided with a Z-support surface (24) for a clamp element (26).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention relates to a clamping device constructed according to the preamble of claim 1 . [Background technology]

[0002] Clamping devices of the type according to the invention serve to clamp clamping elements in place by means of clamping means, where each clamping means is typically rigidly mounted on a clamping base such as a machine table in a processing machine, while the or each clamping element is arranged on a workpiece carrier (pallet).

[0003] To clamp large workpiece carriers with precise positioning, clamping systems are typically used, which include multiple clamping means mounted on a clamping base and a corresponding number of clamping elements attached to the workpiece carrier. Such clamping systems present the problem of having to compensate for dimensional changes of the workpiece carrier relative to the clamping base. Furthermore, care must be taken to ensure that the clamping system is not subject to excessive geometric or mechanical constraints in the X-Y plane.

[0004] Zero-point clamping systems are known in the prior art that include a clamping chuck for tightening a clamping bolt so as to accommodate dimensional changes of the workpiece carrier relative to the clamping base. In this case, the clamping chuck is provided with a radially elastically mounted conical mount for the clamping bolt. Such systems require extremely high manufacturing precision with respect to the infeed elements relative to one another.

[0005] In order to avoid the above-mentioned geometrical over-restriction, EP 0 403 428 A1 discloses a device for clamping workpieces in position. This device comprises at least two chucks with centering pins and a corresponding number of upper sections with clamping spigots and that can be fastened to the chucks. The upper sections are arranged on the workpiece mounts. Each upper section is provided with a centering slit corresponding to the centering spigot. Furthermore, each upper section has a circular clamping spigot (tension bolt) that can be fastened to the central mount of each clamping chuck by means of a clamping ball. Each clamping chuck is provided with four centering spigots, while only one upper section has the corresponding number of centering slits. The other upper sections or each upper section has only two centering slits. Thus, one upper section determines the position of the workpiece mount in the X and Y directions, while the or each other upper section determines its angular position about the Z axis.

[0006] While such devices have proven useful, their construction is relatively complex and only partially suitable for repeatably and accurately clamping large, heavy workpiece carriers, particularly because each circular clamping spigot must be positioned very precisely relative to a similarly circular central mount on each clamping chuck. Furthermore, they can only partially accommodate dimensional changes in the workpiece carrier relative to the clamping chuck.

[0007] Furthermore, EP 1 743 733 A1 discloses a quick clamping device with a replacement cylinder. This quick clamping device includes a closure housing, which is closed from above by a cover, in addition to a retractable nipple to be connected to the pallet. The cover has an inlet opening for the retractable nipple. A catch device for the retractable nipple is arranged inside the closure housing, which consists of a number of locking bodies evenly distributed around the circumference. The locking bodies are actuated by a piston arranged inside the closure housing and biased into a clamping position by a spring assembly. A pot-shaped replacement cylinder is accommodated in the closure housing and is mounted floating within the housing. However, the replacement cylinder is mounted without play in the X-Y plane. This is because the piston is guided radially without play in the cover, and the replacement cylinder also accommodates the piston radially without play.

[0008] EP 0 818 270 A1 discloses a clamping device comprising a clamping element arranged on a machine tool and a tool carrier that can be clamped to the clamping element. The circular clamping element is provided with a central clamping bolt that is inserted without play into the base of the clamping element. The circular workpiece carrier has a central hole, and the clamping bolt of the workpiece carrier can be tightened into the side wall of the central hole. The workpiece carrier is provided with an annular, circumferential, downwardly protruding support member that protects the centering member from damage.

[0009] Finally, German Utility Model No. 29802835 discloses a coupling with two coupling members and a clamping device, which for positioning in the X-Y plane has an xy reference element arranged on the first coupling member and an xy counter-reference element arranged on the second coupling member. The xy counter-reference element arranged on the second coupling member is configured to be rigid, whereas the xy reference element arranged on the first coupling member is configured to be elastically flexible. By appropriately designing the elastic reference element, thermal positional deviations are distributed over several shoulders, i.e., the elastic reference element, so that close positioning tolerances can be maintained. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] European Patent Application Publication No. 0403428 [Patent Document 2] European Patent Application Publication No. 1743733 [Patent Document 3] European Patent Application Publication No. 0818270 [Patent Document 4] German Utility Model No. 29802835 Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention is to provide a clamping device belonging to the technical field mentioned at the beginning, which accommodates or compensates for tolerances or dimensional variations of the clamping elements on the clamping means or of the workpiece carrier clamped by the clamping elements in the X-Y plane without the need for elastic centering elements. The clamping device is furthermore particularly suitable as a module for constructing a clamping system. [Means for solving the problem]

[0012] The solution to this problem is defined by the features of claim 1. According to the invention, a clamping device comprises a clamping means to be fixed on a clamping base and a clamping element that can be tightened onto the clamping means, the clamping means having a clamping module with a clamping member, the clamping module being fixable on the clamping base by means of a fixing element that is configured such that the clamping module can be fixed displaceably in the X-Y plane on the clamping base.

[0013] The clamping modules of the clamping means are fixed displaceably in the X-Y plane on the clamping base by fixing elements, thereby fulfilling a basic prerequisite, whereby each clamping means can absorb dimensional changes of the workpiece carrier to be clamped on the clamping base.

[0014] Preferred embodiments and further configurations of the clamping device are defined in the dependent claims 2-12.

[0015] In a further preferred configuration, the clamping module, in the fixed state of the fixing element, is displaceable relative to the fixing element in the X-Y plane, but is accommodated in the fixing element by a loose fit in the Z direction and is therefore substantially immovable in the Z direction, with the fixing element being provided with a Z support surface for the clamping element. This allows the clamping module to compensate for tolerances in the X-Y plane but transmit clamping forces in the Z direction, and the Z positioning of the clamping element is performed by the immovable fixing element, which, in contrast to the clamping module, can be substantially more easily configured to withstand large forces in the Z direction. Furthermore, the requirements regarding manufacturing tolerances are significantly lower compared to clamping systems with conical centering elements, since the infeed only needs to be large enough to compensate for the tolerances.

[0016] In a further particularly preferred configuration, the fixing element has a centering groove or centering cam, and the clamping element has a centering cam or centering groove corresponding to the centering groove or centering cam of the fixing element in order to be centered in one direction in the X-Y plane relative to the fixing element. This configuration is particularly advantageous for zero-point clamping systems with multiple clamping devices, because the centering element makes it possible to limit the displacement possibility of the clamping module relative to the associated clamping means in one direction, so that due to the corresponding arrangement of the clamping means and the clamping elements, the zero point of the clamping system is always in the same position, regardless of the displacement possibility of each clamping module, thereby enabling extremely precise clamping.

[0017] Preferably, the clamping module is configured substantially cylindrical, the fixing element is configured substantially annular, and the clamping module is accommodated in the fixing element so as to float with radial play in the X-Y plane. This configuration allows for versatility as well as a particularly simple construction of the clamping module. Thanks to this configuration, during assembly, only the centering elements of the clamping means need to be positioned / aligned accurately at an angle, but not the clamping module itself.

[0018] In a further particularly preferred configuration, a circumferential shoulder is provided on the outside of the clamping module, and a recess is provided on the inside of the fixing element, the outer diameter of the shoulder being at least 0.2 mm, in particular at least 0.5 mm, smaller than the diameter of the recess. The difference between the outer diameter of the shoulder and the diameter of the recess is determined by the maximum displacement of the clamping module in the X-Y plane in the fixed state. This configuration can be realized simply and inexpensively.

[0019] The clamping module is preferably received in the fixing element by a clearance fit in the Z direction, in particular by adapting the height of the shoulder to the height of the recess, thereby forming a clearance fit between the shoulder and the recess in the Z direction. This arrangement ensures that the clamping module is form-tightly supported in the fixing element in the Z direction and can transmit a large clamping force, despite the clamping module being displaceable in the X-Y plane.

[0020] In a further preferred configuration, the clamping module is provided with a plurality of clamping elements distributed over the circumferential direction, with the inside of the clamping elements being provided with an annularly circumferential clamping surface against which the clamping elements rest for clamping. This configuration is particularly advantageously suited to transmitting large clamping forces, since a very large number of clamping elements, of the order of about 10-20, can be provided in the circumferentially distributed clamping module, which allows the clamping module to have a correspondingly large clamping surface.

[0021] Particularly preferably, the clamping module has a spring-loaded actuating piston arranged to actuate the clamping element axially movably inside the clamping module, which is simple to implement and allows the function of the clamping means to be reliably achieved.

[0022] Particularly preferably, the actuating piston is under the action of a spring and can be pneumatically or hydraulically displaced from an actuating position, in which it presses the clamping elements radially outward, to a starting position, in which the clamping elements are released and can be displaced radially inward. In this configuration, the actuating piston remains in its actuating position even in the absence of pressure due to the action of the spring, so that the respective clamping element is securely clamped on the clamping means even in the event of a pressure drop, for example in a pneumatic or hydraulic system. This is in particular because the actuating piston is held in its actuating position in a particularly self-locking manner.

[0023] Preferably, the actuating piston is operatively connected to an ejection element displaceable in the Z direction, which can be moved by the actuating piston over the upper side of the clamping module. Such an ejection element can function as a kind of shock absorber during positioning of the workpiece carrier. Furthermore, the workpiece carrier can be slightly raised by the ejection element, which is particularly advantageous for bringing the workpiece carrier into the starting position in which the clamping members are pushed back by the clamping element.

[0024] In a further particularly preferred configuration of the clamping device, the actuating pistons have depressions extending in the Z direction which are aligned with the clamping elements in such a way that, in the actuating position of the actuating pistons, they bear at least linearly against the clamping elements, such that when a large clamping force acts on the clamping elements under load, i.e. when the clamping element is tightened, an enlarged support surface is provided between each clamping element and the actuating piston, thereby enabling the transmission of significantly larger forces than in conventional clamping devices in which the clamping balls bear point-wise against a flat surface.

[0025] Preferably, the upper side of the clamping module is configured in the shape of a frustum and the ejection element is arranged in the center of the frustum, which configuration serves to center the workpiece carrier or the clamping element relative to the clamping means after rough alignment has been achieved by the clamping element automatically sliding along the frustum to center itself when positioning the workpiece carrier or the clamping element.

[0026] In a further embodiment of the present invention, a clamping system is provided in which clamping devices constructed according to the present invention are particularly advantageously arranged to form a clamping assembly. Such a clamping system is defined by the features of claim 13 and is particularly advantageously suited to clamping large to extra-large workpiece carriers. Each clamping module is mounted so as to be floating or displaceable in the X-Y plane, and each clamping means is provided with a first centering element for centering each clamping element in one direction in the X-Y plane relative to the clamping means, and the associated clamping element is provided with a further centering element corresponding to the first centering element (the orientations in the X-Y plane are different for at least two clamping means and two clamping elements arranged corresponding to at least two clamping means), thereby making it possible to accommodate dimensional changes of the workpiece carrier with a consistent zero point and high clamping accuracy.

[0027] Further preferred configurations of the clamping system are defined in the dependent claims 14-17.

[0028] In a further preferred configuration of the clamping system, the clamping base is configured substantially rectangular and has an even number of clamping means, with a clamping means arranged at least in each corner region, and the longitudinal center axis passing through the centering element of each clamping means arranged in the corner region also passes through the centers of the clamping means located diagonally to one another. This configuration results in a very stable clamping system that is able to absorb dimensional changes of the workpiece carrier, in particular due to heat.

[0029] In a further preferred configuration of the clamping system, the workpiece carrier is configured substantially rectangular, with clamping elements arranged at least in each corner region, and the longitudinal center axis passing through the centering elements of each clamping element arranged in the corner regions also passes through the centers of the clamping elements located diagonally to one another, thereby ensuring that the zero point of the clamping system is at a defined position and remains in that position even if individual or all clamping modules are moved to accommodate dimensional changes in the workpiece carrier in the X-Y plane.

[0030] Particularly preferably, each clamping element is arranged in a recess in the workpiece carrier such that the flat underside of each clamping element is recessed relative to the underside of the workpiece carrier, so that each clamping element is accommodated in the workpiece carrier in a manner that is particularly protected against mechanical damage.

[0031] Finally, claim 18 defines a clamping element that is particularly advantageously suitable for use in a clamping device according to any one of claims 1 to 12 or in a clamping system according to any one of claims 13 to 17. Such a clamping element is robust, simple in design and inexpensive to manufacture.

[0032] Further advantageous embodiments and feature combinations of the invention will become apparent from the following detailed description and the claims as a whole. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a perspective view of a clamping device consisting of a clamping means and a clamping element; FIG. [Figure 2] FIG. 2 is an exploded view showing the individual parts of the clamping device in FIG. [Figure 3] FIG. 2 is a cross-sectional view showing the clamping means and the clamping element. [Figure 4]FIG. 2 is a cross-sectional view of the clamping means in the starting position with the clamping element loosely positioned on the clamping means and fixed to the workpiece carrier; [Figure 5] 3 is a cross-sectional view of a clamping means with a clamping element clamped thereon and fixed to a workpiece carrier; FIG. [Figure 6] 1 is a perspective view of a clamping system having four clamping means constructed in accordance with the present invention; FIG. [Figure 7] 1 is a perspective view of a clamping system having three clamping means constructed in accordance with the present invention; FIG. [Figure 8] 10A-10C are diagrams illustrating alternative exemplary embodiments of clamping means and workpiece carriers; DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 shows a perspective view of a clamping device. The clamping device includes a clamping means 1, also referred to as a clamping chuck, which is fixed to a clamping base, such as a machine table, and a clamping element 26, which can be fastened to the clamping means and is arranged on a pallet that serves as a workpiece carrier or tool carrier. The clamping means 1 and the clamping element 26 are fixed to the clamping base and the workpiece carrier, respectively, by a number of screws 30, 31 (some of which are shown). The clamping means 1 includes a clamping module 2 and a fixing element 3. The fixing element 3 serves to fix the clamping module 2 floatingly on the clamping base, so that the clamping module 2 can still be displaced in the X-Y plane after the fixing element is attached. Specifically, the clamping module 2 is fixed to the clamping base / machine table by the fixing element 3 so that it can move within the X-Y plane formed by the upper side of the clamping base relative to the fixing element 3 on the order of approximately ±0.1 to 1 mm. In some embodiments, even larger movements, for example, up to approximately ±2 mm, are possible. This will be explained more precisely in more detail below. The clamping module 2 is provided with a plurality of clamping members in the form of clamping balls 15 distributed along the circumferential direction, by means of which a clamping element 26 can be clamped onto the clamping means 1. The substantially annularly configured fixing element 3 is provided with diametrically opposed centering grooves 23, which are configured and arranged to correspond to two centering cams 28 arranged on the clamping element 26. These centering elements 23, 28 allow the clamping element 26 to be aligned in one direction when it is clamped onto the clamping means 1.

[0035] FIG. 2 is an exploded view showing the individual key components of the clamping means 1, with the help of which the structure of the clamping means 1 can be explained in more detail. Viewed from bottom to top, the clamping module 2 comprises an actuating piston 4, three compression springs 8, an insert 9, three tappets, a retaining ring 11, a clamp housing 13 with a radial bore 14 for accommodating a clamping ball 15, and an ejection element 19. The actuating piston 4, which is to be disposed inside the clamp housing 13, is provided with an annular groove 5 into which the inside of the clamping ball 15 can extend. The groove 5 is bounded on both sides by obliquely extending annular surfaces. A pressure surface 6, which extends along the outer periphery of the actuating piston 4 and decreases in diameter downward, is located above the groove 5. When the actuating piston 4 descends, the pressure surface 6 acts to actuate the clamping ball 15 by pushing it outward, i.e., out of the clamp housing 13. The pressure surface 6 is formed with recesses 7 extending in the axial direction, i.e., the Z direction, which are coordinated with the clamping balls 15 so that, when a large clamping force is transmitted, an enlarged support surface is provided between each clamping ball 15 and the actuating piston 4, thereby enabling the transmission of a larger clamping force than in conventional clamping devices in which the clamping balls abut against a flat clamping surface in a point-like manner.

[0036] The underside of the clamp housing 13 is provided with an annular shoulder 16, which serves to fix the clamp housing 13 or the clamping module 2 to the clamp base by means of the fixing element 3. The upper side of the clamp housing 13 is frustum-shaped, thus forming a conical centering surface 18. This frustum-shaped upper side of the clamp housing 13 is provided with a central hole 17, which serves to receive an ejection element 19. The ejection element 19, located in the center of the frustum, is provided with a conical upper side that is at least partially adapted to the shape and inclination of the frustum-shaped upper side of the clamp housing 13. Together with the ejection element 19, the frustum-shaped upper side of the clamp housing 13 therefore forms a large centering surface for the clamping element when it is placed on the clamping module 2.

[0037] The inside of the fixing element 3 is provided with a circumferential recess in the form of a groove 21 adapted to the shoulder 16 of the clamping housing 13. In the Z direction, the groove 21 is defined by a protrusion 22 extending inwardly and upward, which protrusion 22 forms a Z stop for the shoulder 16. The groove 21 has a diameter slightly larger than the shoulder of the clamping housing 13, thereby allowing a floating or displaceable fixing of the clamping module 2 in the X-Y plane, as will be explained in more detail below. The upper side of the fixing element 3 is provided with a raised support surface 24 that serves as a Z support for the flat underside of the clamping element. Since the fixing element 3 abuts its large-area underside against the clamp base, it can withstand large clamping forces acting in the Z direction against the support surface 24 with a simple structure. In any case, providing such a Z support surface in the clamping module 2 for the workpiece carrier or clamping element 26 would be substantially more complicated. Furthermore, two centering grooves 23 are shown in the fixing element 3, located diametrically opposite each other.

[0038] FIG. 3 shows a cross-section of the clamping element 26 in the region of the centering cam 28 as well as the clamping means 1 in the locked state. The clamping module 2 is fixed on a clamping base 50 (shown only diagrammatically) by means of a fixing element 3. In the fixed state, the annular shoulder 16 of the clamping module 2 extends radially in a groove 21 of the fixing element. There is a so-called "clearance fit" between the upper side of the shoulder 16 and the upper defining part of the groove 21 in the fixing element, i.e., a very small distance of the order of a few micrometers, for example in accordance with ISO H7 / g6, between the upper side of the shoulder 16 and the upper defining part of the groove 21. In the centered state of the clamping module 2, a circumferential gap S exists radially between the side surface of the shoulder 16 and the side wall of the groove 21 in the fixing element. This gap S allows the clamping module 2 to be displaced radially, i.e., in the X-Y plane, in all directions from the central position shown, by the amount of the gap S, which in the illustrated example is sometimes also referred to as a floating mounting. The size of this gap S determines the maximum displacement path of the clamping module 2 relative to the fixing element 3. Preferably, the gap S is at least 0.1 mm, so that the clamping module can be displaced by at least ±0.1 mm in the X-Y plane from its central position. However, a floating mounting does not necessarily mean that the clamping module can be displaced in all directions, i.e., 360°. Rather, if applicable, it may be sufficient to limit the area of ​​displaceable or floating mounting, and in extreme cases, to limit the displacement possibility to one direction. In a medium-sized clamping device, the outer diameter of the shoulder 16 is approximately 0.2 mm to 1 mm smaller than the recess 21 in the fixing element 3, so that the clamping module can be displaced radially from its central position in the X-Y plane by approximately 0.1 mm to 0.5 mm. By medium size, it is understood that the clamping module 2 in the clamping means 1 has a diameter of approximately 8 to 12 cm and a height of approximately 5 to 8 cm. The size of the gap S or the difference between the outer diameter of the shoulder 16 and the inner diameter of the recess 21 depends, inter alia, on the size of the respective clamping means. This is because different sizes can be provided, especially for different sized workpiece carriers.It should be understood that larger workpiece carriers may be subject to greater dimensional changes, especially those caused by heat, in absolute terms. Another criterion for the size of the gap S depends on the materials used for the workpiece carrier and the clamping base, since different materials typically have different thermal expansion coefficients. This is often the case in practice, for example, with a steel clamping base and an aluminum workpiece carrier. Therefore, it is quite conceivable that in certain embodiments a gap S of more than 1 millimeter will be provided. For example, in certain constructions, especially in very large embodiments, a gap S of up to the order of approximately 2 mm can be provided, which corresponds to a displacement path of ±2 mm for the clamping module 2 relative to the fixing element 3.

[0039] The actuating piston 4, located inside the clamping module 2, is displaceable in the axial direction, i.e., the Z direction, between an upper starting position shown in the figure and a lower locked position. In the illustrated embodiment, the actuating piston 4, under the action of a compression spring, is in a downwardly displaced locked position. When the actuating piston 4 descends, it presses the clamping ball 15 radially outward by means of a pressure surface 6, which is located on its outer side and widens slightly upward in a conical shape. Beneath the actual pressure surface 6, a lifting surface 6a extends, which, in contrast to the pressure surface 6, forms a small angle with the horizontal. During the first phase of the actuating piston 4's downward movement, the lifting surface 6a causes the clamping ball 15 to be displaced radially outward more rapidly or farther with each stroke of the actuating piston 4. In the second phase, the pressure surface 6 causes only a relatively small radial displacement of the clamping ball 15 with each stroke of the actuating piston 4. Additionally, the shape of the pressure surface 6 is designed so that the actuating piston 4 remains in the locked position by self-locking. Such a two-stage "infeed" configuration, combined with the floating mounting of each clamping module, reduces the requirements for manufacturing tolerances of the elements that are critical for centering, compared to conical centering, which must be very precisely adjusted to one another.

[0040] Furthermore, in the cross-sectional view of FIG. 3, it can be seen that the hydraulic and pneumatic lines 33 and 36 lead from below through the shaft of the insert 8 into the interior of the clamping module 2. The hydraulic and pneumatic connection lines 33a and 36a are only shown diagrammatically. In any case, the two connection lines 33a and 36a are configured to ensure a firm connection even if the clamping module 2 is radially displaced within a given framework. The hydraulic line 33 opens radially into an annular space 34 located above the central part of the working piston 4, which can be hydraulically loaded with excess pressure. The pneumatic line 36 is connected to a number of cleaning openings 37, through which air can be blown out to clean the opposing surface. One side of one of the centering grooves 23 is provided with an exhaust opening 37a of enlarged diameter. Because the pressure in the pneumatic line drops rapidly through such an exhaust opening 37a, the exhaust opening 37a, when not closed / sealed by a centering cam, can be used, in particular, to detect whether a workpiece carrier with a clamping element 26 is present and firmly clamped on the clamping means 1. A further advantage of the enlarged exhaust opening 37a, having a diameter of at least 2 mm, is that it is less susceptible to contamination and is virtually free of clogging compared to smaller openings, e.g., having a diameter of less than 1.5 mm. Furthermore, the hydraulic line 35 leading into the pressure chamber 32 located below the working piston 4 is shown. The conically extending centering surface 18 is shown on the upper side of the clamping module 2. Additionally, one of the three tappets 10 and one of the three compression springs are shown. The shaft of each tappet 10 is partially housed in a hole 38 in the working piston 4, the depth of the hole 38 being configured so that when the working piston 4 rises, the end of the tappet shaft only fully rests on the bottom of the hole 38 at the end of its upward movement, and the ejection element 19 is pressed by the working piston 4 at the end of its upward lifting movement.To move the working piston 4 towards its upward starting position, the pressure chamber 32 below the working piston 4 is hydraulically loaded with excess pressure, which displaces the working piston 4 upward against the forces of three compression springs.

[0041] Compared to clamping systems with clamping spigots arranged on the workpiece carrier and correspondingly configured clamping chucks, significantly higher clamping forces can be achieved in a clamping device configured according to the invention, since the annularly configured clamping element 26, which radially surrounds the clamping module 2, has a significantly larger clamping surface, and in particular the cylindrical clamping module 2 has a relatively large outer diameter and a significantly larger number of clamping members 15 compared to conventional clamping chucks. Due to the recesses in the working piston 4, the individual clamping members 15 can transmit even greater forces.

[0042] FIG. 4 shows the clamping means in a cross-sectional view in a starting position, with the clamping elements 26 loosely positioned on the clamping means and positioned in stepped recesses 45 of the workpiece carrier 44. The flat undersides of the clamping elements 26, which function as Z supports, and the centering cams 28 of the clamping elements 26 are retracted relative to the underside 48 of the workpiece carrier 44. This allows each clamping element 26 to be securely housed in the workpiece carrier 44. For accurate alignment of the clamping elements 3 before fastening them to the clamping base 50, pins 42 are provided, which are inserted into corresponding blind holes in the clamping elements 3 and the clamping base 50. Similarly, pins 43 are provided for centering the clamping elements 26 relative to the workpiece carrier 44. Conventional screw connections are provided for fastening the clamping elements 3 on the clamping base 50, but details of these connections will be omitted. The clamping elements 26 are also screwed to the workpiece carrier 44, but details of these connections will be omitted. To displace the working piston 4 into the upward starting position shown in the figure, the pressure chamber 32 below the piston 4 is loaded with overpressure. During the upward movement of the working piston 4, each tappet 10 stands at the bottom of its bore in the working piston 4 just before the end of its upward movement and is involved in the final part of the upward movement. This causes the tappet 10 to press the ejection element 19 approximately 1 mm beyond the upper side of the clamping housing 13, so that the ejection element 19 contacts the bottom of the stepped recess 45 and the workpiece carrier 44 is supported or slightly raised in the Z direction.

[0043] In the raised position, the annular groove 5 of the actuating piston 4 is located at the height of the clamping members 15, so that each clamping member can be displaced inward into the annular groove 5, and therefore in the starting position of the clamping means 1 shown, the clamping element 26 can be placed on or removed from the clamping means 1.

[0044] Both the depth of the recess 45 and the height of the step 46 are adjusted to the clamping means 1 together with the clamping module 2 so that the workpiece carrier 44 abuts against the ejection element 19 when placed in the clamping means 1. Specifically, the ejection element 19 abuts against the bottom of the stepped recess 45 before the clamping element 26, via its cam, engages in the groove of the clamping means and is finally centered in one direction in the X-Y plane. In any case, the elements, i.e., workpiece carrier 44, recess 45, clamping element 26, and clamping means 1 / ejection element 19, are adjusted relative to one another so that, when the workpiece carrier 44 is loosely placed, there is a gap of the order of about 1 mm between the Z support 24 of the clamping means 1 (see FIG. 1 ) and the flat underside 28 of the clamping element 26 (see FIG. 1 ). In this case, the cam of the clamping element 26 engages in the groove of the clamping means 1, roughly centering the clamping element 26 relative to the clamping means 1 in one direction in the X-Y plane. Due to the fact that the clamping elements 26 fit into recesses in the workpiece carrier 44 and that their flat undersides, which act as Z-centering features, are recessed relative to the underside 49 of the workpiece carrier 44, the clamping elements 26 are effectively protected from external influences, such as mechanical damage. Instead of a continuously flat underside 29, the clamping elements 26 may also only partially have flat surface portions.

[0045] 5 shows the clamping means in the locked position, together with a workpiece carrier 44 clamped onto the clamping means 1 by the clamping elements 26. To allow the working piston 4 to move from its starting position to the locked position shown, the excess pressure in the pressure chamber 32 is reduced, which causes the working piston 4 to move downwards under the action of the compression spring 8. In this case, the working piston presses the clamping balls 15 radially outward with the pressure surfaces 6 arranged on its outside and slightly conically widening upwards. The clamping balls 15 come into contact with the annularly circumferential clamping surfaces 27 (see FIG. 3) of the clamping elements 26 and pull the clamping surfaces 27 downwards in the Z direction until the flat underside of the clamping elements 26 abuts against the Z support 24 (see FIG. 1) of the clamping means 1. If the ejection element 19 does not automatically move to its lower rest position when the working piston 4 descends, the ejection element 19 is pressed downwards by the bottom of the recess 45 in the workpiece carrier 44, in particular because the tappet 10 no longer stands at the bottom of the hole 38 in the working piston 4 and can be displaced downwards together with the ejection element 19.

[0046] When clamping element 26 is tightened onto clamping means 1, the cams of clamping element 26 abut on the grooves of the clamping means, precisely centering clamping element 26 in one direction in the X-Y plane relative to clamping means 1. Preferably, the spigot-groove centering elements are adjusted relative to one another so that both lateral sides of the centering spigot abut against both groove walls of each centering groove before the flat underside of clamping element 26 is placed on Z support 24 (see FIG. 1 ) of clamping means 1, i.e., while there is still a gap of the order of a few micrometers to a few hundredths of a millimeter between the underside of clamping element 26 and Z support 24. In this way, fine centering between clamping element 26 and clamping means 1 is completed before clamping element 26 abuts on the Z support of the clamping means.

[0047] In order to be able to complete the centering process in the Z direction, the elements of the clamping device essential for this centering process are coordinated with one another in terms of size and shape in such a way that the above-mentioned gap between the flat underside of the clamping elements and the Z support 24 of the clamping means 1 can be eliminated by utilizing material elasticity in the area of ​​the centering spigot and centering groove. It is therefore not necessary to provide spring-elastic deflection elements in the Z direction, as are present in many clamping systems constructed according to the prior art.

[0048] After clamping element 26 has been tightened onto clamping means 1, the clamping force can be further increased by hydraulically or pneumatically loading the annular space 34 above working piston 4. Working piston 4 is held in the locked position by self-locking, so that a high clamping force is maintained even after the hydraulic or pneumatic overpressure has been removed.

[0049] The flushing openings (including the enlarged exhaust openings) supplied via the pneumatic line 36 are arranged to be closed / sealed when the clamping element 26 or each of its centering elements tightens the clamping element 26 onto the clamping means 1. This makes it possible to monitor the pressure or air flow in the pneumatic line 36 to ascertain whether the clamping element 26 is present and, if so, whether it is securely tightened.

[0050] The clamping devices shown in FIGS. 1 to 5 form basic elements for forming clamping systems that can clamp, in particular, large and / or heavy workpieces or workpiece carriers to the working area of ​​processing machines, such as milling machines, grinding machines, EDM machines, or lathes. The term large or extra-large workpiece carrier is understood to mean a workpiece carrier typically having dimensions of approximately 0.5 m to 2 m. Workpieces with a total weight of up to several thousand kilograms can be fixed on such workpiece carriers. In any case, such clamping devices form modular components, which allow large to extra-large clamping systems to be realized.

[0051] 6 shows a first embodiment of such a clamping system comprising four clamping means 1a, 1b, 1c, 1d arranged on a clamping base 50 to form a clamping assembly, and four clamping elements 26a, 26b, 26c, 26d arranged on a workpiece carrier 44. As shown, the X and Y axes are parallel to the upper side / surface of the clamping base 50, whereas the Z direction is perpendicular to the X and Y axes. The X-Y plane of the clamping arrangement is thus defined by the upper side / surface of the clamping base 50.

[0052] The four clamping means 1a-1d are arranged on the upper side of a clamping base 50, and the four clamping elements 26a-26d are fixed in corresponding recesses 45a, 45b, 45c, and 45d in a workpiece carrier 44. The clamping base 50 may be, for example, a table of a processing machine. The clamping means 1a-1d and the clamping elements 26a-26d are configured according to the exemplary embodiment described above. The workpiece carrier 44 has a continuous, flat underside 48. In this case, the upper side of the clamping base 50 also forms the X-Y plane. The advantages of the floating or displaceable fixation of each clamping module 2a-2d in the X-Y plane are particularly apparent in clamping assemblies including three or more clamping means. In each of the four clamping means 1a-1d, the clamping modules 2a-2d are floatingly mounted, while the four clamping elements 26a-26d are rigidly and immovably connected to the workpiece carrier 44. In the clamping means 1a, 1c; 1b, 1d or fixing elements 3a, 3c; 3b, 3d that are diagonally arranged, the centering grooves lie on a common longitudinal central axis L1, L2, whereas in the clamping elements 26a, 26c; 26b, 26d that are diagonally arranged, the centering cams 28a, 28c; 28b, 28d lie on a common longitudinal central axis M1, M2. In this case, the grooves 23a, 23b, 23c, 23d of the four clamping means 1a-1d or fixing elements 3a, 3b, 3c, 3d are arranged to correspond in position and alignment to the clamping elements 26a-26d (including these centering cams 28a-28d), so that the workpiece carrier 44 is aligned in the X, Y, and Z directions when clamped by the four clamping means 1a-1d. The clamp modules 2a to 2d are accommodated in a floating manner on the fixing elements 3a to 3d in the radial direction or in the X-Y plane, so that changes in the length of the workpiece carrier 44 relative to the clamp base 50 can be accommodated or equalized to a certain extent.However, care must be taken when mounting that the distance between the centers of the fixing elements 3a-3d fixed on the clamping base 50 corresponds as precisely as possible to the distance between the centers of the clamping elements 26a-26d fixed on the workpiece carrier 44, not only laterally but also diagonally, so that the clamping modules 2a-2d can equalize dimensional changes (expansion or contraction) of the workpiece carrier 44 relative to the clamping base 50 in the radial direction, i.e., in the X-Y plane. This results in a self-centering clamping system that avoids excessive mechanical constraints in the X-Y plane. The two-stage "infeed" of the clamping modules 2 or actuating pistons and the fact that each clamping module 2 is mounted so as to float in the X-Y plane place relatively small demands on the manufacturing tolerances of the elements critical for clamping and centering, namely the fixing elements 3 and the clamping elements 26.

[0053] When mounting the clamping means 1a-1d on the clamping base 50 and the clamping modules 2a-2d on the workpiece carrier 44, care must be taken to ensure that the clamping base 50 and the workpiece carrier 44 have approximately the same temperature, so that dimensional changes of the workpiece carrier 44, e.g., due to heat, can be absorbed / equalized in both directions. The zero point in such a clamping system is located at the intersection P of two central longitudinal axes L1, L2 of the clamping means 1a-1d, which are diagonally positioned on the clamping base 50. In any case, the zero point P does not move even when each clamping module moves in a predetermined direction in the X-Y plane to accommodate dimensional changes of the workpiece carrier 44, e.g., due to heat. Therefore, at the predetermined zero point, the workpiece carrier 44 can be accurately and repeatedly clamped onto the clamping base 50. Tests have shown that a repeatability accuracy for clamping the workpiece carrier 44 of the order of approximately ±5 micrometers can be achieved.

[0054] As shown in Figure 6, in the case of a square clamping base, the centering elements (centering grooves) of adjacent clamping means are rotated approximately 90° relative to one another, and the longitudinal center axes L1, L2 intersect at 90° relative to one another. The same applies to a square workpiece carrier, in which the centering elements (centering cams) of adjacent clamping elements are also rotated approximately 90° relative to one another. In the case of a clamping base that is rectangular rather than square, the intersection angle of the longitudinal center axes L1, L2 generally deviates from 90°.

[0055] The large-area conical centering surfaces 18 (see FIG. 3) of the clamping modules 2a-2c of the clamping means 1a-1d make it relatively easy to position the workpiece carrier 44 relative to the clamping base 50. Because an average-sized clamping device, whose clamping modules 2a-2c have diameters on the order of approximately 8-12 cm, each clamping element 26 itself is centered to a lateral offset of up to approximately 2 cm when placed in position relative to the associated clamping means. Therefore, it is sufficient to roughly position the workpiece carrier 44 relative to the clamping base 50, i.e., by approximately 1-2 cm, before placing it in position. Subsequent fine positioning is achieved during lowering by sliding the underside of each clamping element 26a-26d along the conical surface of the associated clamping module 2a-2d until it is concentrically aligned with the associated clamping module 2a-2d. Furthermore, during this centering process, the clamping modules 2a-2d can move along a predetermined direction in the X-Y plane and, thanks to their floating mounting, can be aligned with the associated clamping elements 26a-26d by substantially corresponding to the diagonal distance of the associated clamping elements 26a-26c. The workpiece carrier 44 is then lowered so that the centering cams of each clamping element 26a-26d engage with the grooves in the corresponding fastening elements 3a-3d, thereby accurately aligning the workpiece carrier 44 at an accurate angle. During subsequent clamping of the workpiece carrier 44, the clamping balls of the clamping modules 2a-2d engage with each clamping element 26a-26d, causing the clamping modules 2a-2d to move accurately toward the center of the corresponding clamping element 26a-26d, thereby also accurately matching the diagonal distance. In this case, the clamping balls of the clamping modules 2a to 2d pull each of the clamping elements 26a to 26d downward until the flat underside of each of the clamping elements 26a to 26d abuts on the Z support of each of the fixing elements 3a to 3c.If the fixing elements 3a-3d are fixed on the clamping base 50 and each clamping module 2a-2d is accommodated in the respective fixing element 3a-3d in the Z direction by a loose fit, the clamping modules 2a-2d cannot "deflect" upwards when clamping the workpiece carrier 44, and therefore a sufficiently large clamping force can be applied and transmitted in the Z direction. If it is stated that the fixing element 3 is not displaceable in the Z direction, this does not mean that it will not yield in the Z direction within extremely small tolerances of a few micrometers, caused on the one hand by the play of the loose fit and on the other hand by the elasticity of the different elements and materials.

[0056] FIG. 7 shows an alternative embodiment of a clamping system suitable for smaller workpiece carriers. The illustrated clamping system comprises three clamping means 1a, 1b, and 1c arranged on a clamping base 50 and three clamping elements 26a, 26b, and 26c arranged on a workpiece carrier 44. The clamping means 1a, 1b, and 1c are uniformly distributed on the clamping base, so that all three clamping means 1a-1c are at the same distance from one another. The longitudinal central axes L1, L2, and L3 passing through the centering elements (grooves) of the fixing elements 3a, 3b, and 3c arranged on the clamping base form angles of 120° with one another. In the illustrated example, the zero point is located at the intersection P2 of the three longitudinal central axes L1-L3. The clamping elements 26a-26c arranged on the workpiece carrier 44 are arranged to correspond to the clamping means 1a-1c on the clamping base 50. In the clamped state, the longitudinal central axes M1, M2, M3 of the workpiece carrier 44 passing through the centering elements (cams) are parallel to the longitudinal central axes L1 to L3 passing through the centering elements (grooves) of the fixing elements 3a to 3c.

[0057] The mode of operation of clamping the workpiece carrier 44 onto the clamp base 50 or onto the clamp assembly is essentially the same as in the exemplary embodiment in FIG. 6, and therefore will not be described in further detail here.

[0058] FIG. 8 shows an alternative exemplary embodiment of a clamping system including a circular clamp base 50a and a circular workpiece carrier 44a. The clamping means and clamping elements are configured similarly to those in FIG. 6 and are therefore designated by the same reference numerals. The illustrated clamping system includes four clamping means 1a, 1b, 1c, and 1c uniformly distributed around the circumference on the clamp base 50 to form a clamp assembly, and four corresponding clamping elements 26a, 26b, 26c, and 26d disposed on the workpiece carrier 44. Again, the X and Y axes are parallel to the upper side / surface of the clamp base 50a and form the X-Y plane, while the Z direction is perpendicular to the X and Y axes.

[0059] The four clamping means 1a-1d are arranged on the upper side of the clamping base 50a, preferably in its outer region, i.e., away from the center, while the clamping elements 26a-26d are arranged corresponding to the four clamping means and are protectively housed in corresponding recesses 45a, 45b, 45c, 45d in the workpiece carrier 44. The clamping modules 2a-2d are also mounted so as to float in the X-Y plane. In the diametrically opposite clamping means 1a, 1c; 1b, 1d or fixing elements 3a, 3c; 3b, 3d, the centering grooves 23a, 23c; 23b, 23d also lie on a common longitudinal center axis L1, L2, while in the diametrically opposite clamping elements 26a, 26c; 26b, 26d, the centering cams 28a, 28c; 28b, 28d lie on a common longitudinal center axis M1, M2. In this case, the grooves 23a, 23b, 23c, 23d of the four clamping means 1a to 1d or fixing elements 3a, 3b, 3c, 3d are arranged in terms of position and alignment to correspond to the clamping elements 26a to 26d (including their centering cams 28a to 28d), so that the workpiece carrier 44a is aligned in the X, Y, and Z directions when the workpiece carrier 44 is clamped by the four clamping means 1a to 1d.

[0060] Again, arranging the clamping means 1a, 1b, 1c, 1d in the outer region of the clamping base 50a has the advantage that such a clamping device can accommodate both very large torsional moments and very large tilting moments.

[0061] The longitudinal center axes L1, L2 passing through each centering element (centering grooves 23a, 23b, 23c, 23d) of the clamp modules 2a to 2d intersect at the center P1 of the clamp base 50a, while the longitudinal center axes M1, M2 passing through each centering element (centering cams 28a, 28b, 28c, 28d) of the clamp elements 26a to 26d intersect at the center P2 of the workpiece carrier 44a.

[0062] If desired, it is of course also possible to combine a circular clamping base with a rectangular workpiece carrier or vice versa.

[0063] It should be understood that the exemplary embodiments described above are not to be considered definitive or comprehensive. Therefore, within the scope of the present invention, clamping systems with more than three or more than four clamping means are also possible, as alternatives to the exemplary embodiments in FIGS. 6, 7, and 8. For example, clamping systems with six or eight clamping means can be formed. In the case of very large clamping systems, each clamping module can be displaced radially, i.e., in the X-Y plane, by more than the aforementioned 0.5 mm. In the case of more than four clamping means, it is not necessary for all clamping means or each clamping element to be provided with a centering element (centering groove / centering cam). In some cases, individual clamping means and / or clamping elements may not be provided with a centering element, thereby each clamping means only having a clamping function and not a centering function. Furthermore, the term workpiece carrier does not necessarily refer to an element for receiving a workpiece; in some cases, a tool or other different object can be fixed on the tool. In this case, the clamping element may be fixed directly on the workpiece, and the workpiece itself can therefore function as a workpiece carrier. Furthermore, the workpiece carrier need not be circular or rectangular, but may be, for example, oval, hexagonal, or octagonal.

[0064] Some advantages of the clamping means or clamping system constructed according to the present invention can be summarized as follows: - Each clamping module is mounted in a floating manner so that it can be displaced after being fixed in the X-Y plane, thereby absorbing dimensional changes of the workpiece carrier with extremely high clamping accuracy; - the floating mounting of the clamping module makes it possible to avoid mechanical over-constraint of the clamping system in the X-Y plane; - each clamping module is capable of generating very high clamping and holding forces as well as absorbing high lateral forces; - the clamping means or each clamping module is constructed simply and compactly and has a relatively small overall height; - the clamping elements can be fixed to the workpiece carrier in a mechanically protected manner; - Due to the modularly constructed clamping means and clamping elements, average to extra-large clamping systems can be realized for average to very large and heavy workpiece carriers; - very large workpiece carriers can be clamped onto the clamping base with a repeatability accuracy in the range of approximately 10-20 micrometers; - the clamping means can be easily and quickly arranged on variously configured clamping bases; - the clamping elements can be easily and quickly positioned on variously configured workpiece carriers; - each clamping element is positively locked by a mechanically, possibly also hydraulically or pneumatically loaded actuating piston; - the actuating piston is held in the locked position by a self-locking mechanism, ensuring that the clamping element remains tight even in the event of a power failure; - Compression spring ensures that the clamping force is maintained even in the absence of energy; - the clamping means is designed to be dirt-resistant and can be easily cleaned; - the clamping system is insensitive to temperature-induced changes in the length of the workpiece carrier; - Due to the fact that each clamping means is located in an outer or corner area and is therefore centered and mounted at that position, it can accommodate both very large torsional moments and very large tilting moments, especially compared to clamping means located closer to the center. [Explanation of symbols]

[0065] 1. Clamping means 2 clamping modules 3 Fixed elements 4 working piston 5 Annular groove 6 Pressure Surface 7 Axial recess 8 compression springs 9 Inserts 10 Tappet 11 Retaining ring 12 13 Clamp housing 14 holes 15 Clamp ball (clamping component) 16 Shoulder 17 Central hole 18 Conical centering surface 19 Eject Element 20 21 recess (fixing element) 22 Protrusion (fixed element) 23 Centering groove (fixing element) 24 Z support (fixed element) twenty five 26 Clamping Elements 27 Clamping surface 28 Centering cam 29 Flat Underside 30 Clamping means screw 31 Screws on clamping elements 32 Pressure chamber (below the piston) 33 Hydraulic Line 34 Annular space (above piston) 35 Hydraulic supply line 36 Air pressure line 37 Cleaning opening 38 holes 39 Pressure chamber (above the piston) 40 Underside of clamp module 41 42 base pins 43 Workpiece carrier pin 44 Workpiece carrier (pallet) 45 stepped recess 46 steps 47 Recessed base 48 Underside of workpiece carrier 49 50 Clamp base 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

Claims

1. A clamping device comprising clamping means (1) that can be fixed on a clamp base (50) and a clamping element (26) that can be tightened on the clamping means (1), wherein the clamping means (1) has a clamping module (2) provided with a clamping member (15), and the clamping module (2) can be fixed on the clamp base (50) by a fixing element (3), characterized in that the fixing element (3) is configured such that the clamping module (2) can be displaceably fixed on the clamp base (50) in the X - Y plane formed by the upper side of the clamp base (50).

2. The clamping device according to claim 1, wherein the clamping module (2) in the fixed state of the fixing element (3) is displaceable relative to the fixing element (3) in the X - Y plane, while in the Z direction, it is accommodated in the fixing element (3) by a clearance fit, and the fixing element (3) is provided with a Z support surface (24) for the clamping element (26).

3. The clamping device according to claim 1 or 2, wherein the fixing element (3) has a centering groove (23) or a centering cam, and the clamping element (26) has a centering cam (28) or a centering groove configured to correspond to the centering groove (23) or the centering cam of the fixing element (3) for centering in one direction in the X - Y plane relative to the fixing element (3).

4. The clamping device according to claim 1 or 2, wherein the clamping module (2) is substantially cylindrical in configuration, the fixing element (3) is substantially annular in configuration, and the clamping module (2) is accommodated in the fixing element (3) to float with a radial play in the X - Y plane.

5. The clamping device according to claim 4, wherein a circumferential shoulder (16) is provided outside the clamping module (2), and a recess (21) configured to correspond to the circumferential shoulder (16) on the outside of the clamping module (2) is provided inside the fixing element (3), and the outer diameter of the shoulder (16) is at least 0.2 mm, particularly at least 0.5 mm smaller than the diameter of the recess (21).

6. The clamping device according to claim 5, wherein the clamping module (2) is accommodated in the fixing element (3) in the Z direction by a clearance fit, and in particular, the height of the shoulder (16) is adapted to the height of the recess (21), so that a clearance fit is formed between the shoulder (16) and the recess (21) in the Z direction, and thus the clamping module (2) is accommodated in the fixing element (3).

7. The clamping device according to claim 3, wherein a plurality of clamping members (15) are provided on the clamping module (2) and are distributed circumferentially, and an annular clamping surface (27) is provided inside the clamping element (26), and the clamping members (15) abut against the clamping surface (27) for clamping.

8. The clamping device according to claim 1 or 2, wherein the clamping module (2) has a spring-loaded actuating piston (4), and the actuating piston (4) is arranged to axially move the clamping members (15) inside the clamping module (2).

9. The clamping device according to claim 8, wherein the actuating piston (4) is under the action of a spring (8) and is optionally further loaded pneumatically or hydraulically, and can be displaced pneumatically or hydraulically from an actuating position where the clamping members (15) are pressed radially outward to a starting position where the clamping members (15) are released and can be displaced radially inward, and the actuating piston (4) is particularly held in the actuating position by self-locking.

10. The clamping device according to claim 8, wherein the actuating piston (4) is operatively connectable to an ejecting element (19) displaceable in the Z direction, and the ejecting element (19) is movable beyond the upper side of the clamping module (2) by the actuating piston (4). A clamping device characterized by this.

11. The clamping device according to claim 8, wherein the actuating piston (4) has a recess (7) extending in the Z direction, and the recess (7) is adjusted with the clamping member (15) so as to provide an enlarged support surface between each clamping member (15) and the actuating piston (4) when the clamping element (26) is tightened. A clamping device characterized by this.

12. The clamping device according to claim 10, wherein the upper side of the clamping module (2) is configured in a frustoconical shape, and the ejecting element (19) is arranged at the center of the frustum. A clamping device characterized by this.

13. A clamping system comprising a clamping base (50, 50a), a workpiece carrier (44, 44a), and at least three clamping devices configured according to claim 1, wherein the clamping devices include at least three clamping means (1a, 1b, 1c, 1d) arranged on the clamping base (50, 50a), and a corresponding number of clamping elements (26a, 26b, 26c, 26d) arranged on the workpiece carrier (44, 44a). In a clamping system where the upper side of the clamping base (50, 50a) forms an X - Y plane, In order to align each of the clamping elements (26a, 26b, 26c, 26d) in one direction within the X-Y plane with respect to the clamping means (1a, 1b, 1c, 1d), each of the clamping means (1a, 1b, 1c, 1d) is provided with a first alignment element (23a, 23b, 23c, 23d), and a further alignment element (28a, 28b, 28c, 28d) corresponding to the first alignment element (23a, 23b, 23c, 23d) is provided on the associated clamping element (26a, 26b, 26c, 26d). In at least two clamping means (1a, 1b, 1c, 1d) and two clamping elements (26a, 26b, 26c, 26d) arranged to correspond to the at least two clamping means (1a, 1b, 1c, 1d), the directions in the X-Y plane are different. A clamping system is characterized by this.

14. The clamping system according to claim 13, wherein the clamping base (50) is substantially rectangular in configuration and has an even number of clamping means (1a to 1d), and the clamping means (1a to 1d) are arranged in at least each corner region, and longitudinal central axes (L1, L2) passing through the alignment elements (23a to 23d) of the respective clamping means (1a to 1d) arranged in the corner regions also pass through the center of the clamping means (2a, 2c; 2b, 2d) located diagonally to each other. A clamping system is characterized by this.

15. The clamping system according to claim 13 or 14, wherein the workpiece carrier (44a) is substantially circular in configuration and at least three clamping elements (26a to 26d) are provided in the outer region, and the clamping elements (26a to 26d) are arranged such that longitudinal central axes (M1, M2) passing through the alignment elements (28a to 28d) of the clamping elements (26a to 26d) coincide or intersect at the center of the workpiece carrier (44a). A clamping system is characterized by this.

16. The clamping system according to claim 13 or 14, wherein the workpiece carrier (44) is configured to be substantially rectangular, and clamping elements (26a to 26d) are arranged at least in each corner region, and the longitudinal central axes passing through the centering elements (28a to 28d) of the respective clamping elements (26a to 26d) arranged in the corner regions also pass through the centers of the clamping elements (26a, 26c; 26b, 26d) located diagonally to each other. A clamping system characterized by this.

17. The clamping system according to claim 15, wherein the respective clamping elements (26a to 26d) are arranged in recesses (45a to 45d) of the workpiece carrier (44, 44a) such that the flat lower sides (29) of the respective clamping elements and the centering elements (28a to 28d) are recessed with respect to the lower side (48) of the workpiece carrier (44, 44a). A clamping system characterized by this.

18. A clamping element (26a to 26d) for use in the clamping device according to claim 1 or the clamping system according to claim 13, wherein the clamping element (26) is configured to be substantially annular and has an annularly circumferential clamping surface (27) on the inside, and a clamping member (15) can be brought into contact with the clamping surface (27) for clamping, and the clamping element (26) is at least partially provided with a flat lower side (29) that functions as a Z support portion. A clamping element characterized by this.

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