CLAMPING DEVICE

Description

[0001] The invention relates to a clamping device, in particular for clamping workpieces for machining.

[0002] In the manufacturing industry, particularly in the metalworking industry, processing machines such as drilling and milling machines are used. In order for these machines to work precisely, they require exact reference points. In practice, it is therefore important to be able to clamp a workpiece carrier precisely and repeatedly. To do this, it is necessary to be able to position the workpiece carrier in question precisely in relation to six degrees of freedom, i.e. in three linear coordinates X, Y and Z and three axes of rotation (rotation around the X axis, Y axis or Z axis). If the workpiece is to be clamped as part of a workpiece machining operation, considerable forces acting on the workpiece often have to be taken into account, i.e. they have to be absorbed by the clamping device without the workpiece shifting. The clamping devices in question must therefore be robust.The force transfer between individual elements cannot be carried out at specific points, as this would overload the material on the clamping device and thus lead to deformation. Rapid changeovers are often necessary, so the clamping must be able to be released and re-locked quickly and easily.

[0003] From DE 101 55 077 B4, a clamping device according to the preamble of claim 1 is known, in which a clamping plate can be clamped on a reference plane plate. The clamping device has a flat clamping surface that defines a reference plane and at least two clamping openings with walls. At least one reference surface is formed on each of the walls. The clamping device serves to clamp a clamping plate, which has a flat base surface to be placed on the clamping surface and at least two clamping and positioning bolts. The clamping and positioning bolts are assigned to the clamping openings and each have a positioning surface that is assigned to one of the reference surfaces. Furthermore, the clamping device has a tightening device that is designed to apply an axial force and a superimposed radial force to the clamping and positioning bolts.By means of the axial force, the base surface of the clamping plate can be pressed against the clamping surface of the reference plane plate and by means of the radial force, the clamping and positioning bolts with their positioning surfaces can be pressed against the reference surfaces.

[0004] However, this known clamping device has several disadvantages. Firstly, a complex force redirection with numerous clamping jaws is necessary to allow the user to loosen or tighten the clamping. Accordingly, there are numerous friction surfaces where the forces are redirected. These friction surfaces increase the risk of components accidentally jamming against one another. The high number of components and the complex reference plane plate increase manufacturing costs. Furthermore, automatic centering of the clamping and positioning bolts to be clamped does not always occur, so optimal clamping precision cannot be achieved.

[0005] US 9 902 033 B1 discloses another clamping device, which forms the basis for the preamble of claim 1. In the clamping device of US 9 902 033 B1, a drive spindle for two opposing clamping jaws is fixed in its housing by means of two metal pins and has limited longitudinal movement. This significantly limits the usability of the clamping device because it requires all clamping openings to be occupied by corresponding clamping bolts, as otherwise, a clamping movement of the spindle would exert a shear load on these pins. This is mechanically unfavorable and can lead to component failure.

[0006] The present invention therefore has the object of providing a clamping device for the precise and simple clamping of workpieces or workpiece holders, which enables precise clamping and is inexpensive to manufacture.

[0007] According to the invention, this object is achieved by a clamping device according to claim 1.

[0008] The displaceability of the clamping device and the clamping jaws is designed in particular such that the clamping device is directly and exclusively operatively connected to the clamping jaws in order to move them towards or away from each other. According to the invention, the clamping device is freely movable within the clamping device, which is to be understood as meaning that the clamping device has no bearings, position fixation, or other direct coupling with the clamping device, but is merely positionally determined within the clamping device via the clamping jaws. The degree of displaceability is determined solely by the limits imposed on the clamping jaws within the housing of the clamping device, for example by means of end stops. The accuracy of the clamping process is already achieved through the clamping of the clamping and positioning bolts by the clamping jaws, so that additional fixing of the clamping device is unnecessary.This reduces static overdetermination and installation problems. Another significant advantage is that the invention always ensures reliable clamping, regardless of whether all clamping openings are occupied by clamping and positioning bolts or not, since the range of motion of the clamping device is defined by the mobility of the clamping bolts.

[0009] Furthermore, the axial forces and the radial forces can be applied to the clamping and positioning bolts by means of the clamping device when the two clamping jaws move towards or away from each other.

[0010] For this purpose, the clamping device of the clamping device can transmit a tensile force or a compressive force between the two clamping jaws.

[0011] Alternatively, a tensile force or a compressive force can be transmitted between one of the clamping jaws and the reference plane plate.

[0012] The clamping plate can have two, three, four or more clamping and positioning bolts.

[0013] The reference plane plate can have a corresponding number of clamping openings, or more, to allow the inclusion of different clamping plates.

[0014] The reference plane plate of the clamping device can have multiple sets of clamping openings. This allows the clamping device to accommodate different clamping plates with differently spaced clamping and positioning bolts.

[0015] The reference plane plate preferably has a first set of clamping openings in a first grid with a grid spacing A x A, and a second set of clamping openings in a second grid with a grid spacing B x B, wherein the grid spacing B x B of the second grid is different from the grid spacing A x A of the first grid. This makes it possible to accommodate different clamping plate formats using the corresponding grids.

[0016] The tightening device can have a force-generating means. The compressive force and / or the tensile force can then be generated by means of the force-generating means. A portion of the force-generating means is encompassed by the clamping means.

[0017] Preferably, the force generating means is a threaded arrangement or a fluid-actuated piston-cylinder arrangement or an electromechanical arrangement.

[0018] The clamping device can have a thread of the thread arrangement or a fluid supply of the piston-cylinder arrangement.

[0019] One of the clamping jaws may have a mating thread to the thread of the clamping device, comprise a piston or a cylinder of the piston-cylinder arrangement or be coupled to the piston or the cylinder.

[0020] In a preferred embodiment, the force generating means is designed as a spindle which has at least one thread and is operatively connected to the two clamping jaws in such a way that a rotation of the spindle causes a movement of the clamping jaws towards or away from each other in the direction of the movement axis.

[0021] In a first preferred variant, the spindle has a spindle body, at one end of which the thread is arranged, which engages with a thread of the first clamping jaw, and at the opposite end of which a head portion is formed, which has a larger diameter relative to the spindle body and bears against the second clamping jaw with a contact surface. This embodiment has a mechanically extremely simple, therefore robust, and at the same time inexpensive to manufacture design, which underlines the simplicity of the inventive concept.

[0022] In other words, one of the clamping jaws can have a through-hole for the clamping device, and the other clamping jaw can have the mating thread. The clamping device can have a stop at one end that rests against one end of the through-hole, and a thread at the other end that engages the mating thread. By rotating the clamping device, the clamping jaws can be moved toward or away from each other.

[0023] In a second preferred alternative, the spindle has a spindle body, at one end of which a first thread is arranged, for example a right-hand thread, which engages with a corresponding thread of the first clamping jaw, and at the opposite end of which a second, counter-rotating thread is arranged, for example a left-hand thread, which engages with a corresponding thread of the second clamping jaw. This embodiment has the advantage that, to achieve a predetermined adjustment path of the clamping jaws due to the two counter-rotating threads, only half the rotational movement is required compared to the previously described embodiment, whereby the manufacturing effort increases only slightly.

[0024] The clamping surface can be flat and continuous. It can be interrupted only by the clamping openings. Accordingly, it represents a continuous surface.

[0025] The clamping and positioning bolts can be sized and positioned such that, when they protrude into the clamping openings in the unclamped state, their positioning surfaces are spaced away from the reference surfaces. This allows for easy insertion of the clamping and positioning bolts into the clamping openings. Furthermore, the clearance allows the clamping and positioning bolts to be automatically centered by the tightening device. Accordingly, it is advantageous if the clamping and positioning bolts are undersized relative to the clamping openings.

[0026] Furthermore, the clamping and positioning bolts can be designed to be resilient in the radial direction. If the clamping and positioning bolts are designed to be resilient along their radial direction, the play can be bridged and geometric overdetermination of the clamping device can be prevented. Accordingly, it is advantageous if the maximum spring stroke of the clamping and positioning bolts is greater than the distance between the positioning surfaces of the clamping and positioning bolts and the reference surfaces due to the aforementioned play.

[0027] The reference surfaces of the clamping openings and the positioning surfaces of the clamping and positioning bolts can each be cylindrically curved.

[0028] The radial forces can each have a first force component parallel to the axis of movement and a second force component orthogonal to the axis of movement.

[0029] The clamping device has a first set of clamping openings for receiving the clamping and positioning bolts of a first clamping plate with first distances between the clamping and positioning bolts and a second set of clamping openings for receiving the clamping and positioning bolts of a second clamping plate with second distances between the clamping and positioning bolts.

[0030] Both clamping jaws each have four force transmission surfaces. Two first force transmission surfaces of each clamping jaw can be brought into contact with the force absorption surfaces of the clamping and positioning bolts of the first clamping plate. For this purpose, the clamping and positioning bolts of the first clamping plate can engage with the first set of clamping openings. In addition, two second force transmission surfaces of each of the clamping jaws can be brought into contact with the force absorption surfaces of the clamping and positioning bolts of the second clamping plate. For this purpose, the clamping and positioning bolts of the second clamping plate can engage with the second set of clamping openings.In other words, each clamping jaw has a first pair of force transmission surfaces corresponding to the first grid spacing RA of the first set of clamping openings and a second pair of force transmission surfaces corresponding to the second grid spacing RB of the second set of clamping openings.

[0031] In the clamped state, the force-transmitting surfaces and the force-absorbing surfaces are in contact with each other at a contact surface. A force pointing in the direction of a surface normal to the contact surface can be transmitted at the contact surface, with the force being the vector sum of a radial force and an axial force. The force forms a first angle with a vertical plane parallel to the axis of movement and orthogonal to the reference plane, and it forms a second angle with the reference plane.

[0032] Preferably, the first angle is between 20° and 70°, 30° and 60°, or between 40° and 50°. In a further preferred embodiment, the first angle can be 45°. The second angle can be between 20° and 70°, between 30° and 60°, or preferably 45°.

[0033] The clamping and positioning bolts can be essentially cylindrical.

[0034] The clamping and positioning bolts can have contact recesses that form the force absorption surfaces of the clamping and positioning bolts.

[0035] A contact recess can be wedge-shaped or extend circumferentially around the circumference of a cylindrical clamping and positioning bolt. The contact recess can be provided on one, two, or three sides of each of the clamping and positioning bolts. In such an embodiment, a longitudinal axis of a contact recess does not run circumferentially along the circumference of a cylindrical clamping and positioning bolt, but rather tangentially to it. With a wedge-shaped contact recess, this offers the advantage of a relatively large, flat contact surface between the force transmission surface of the clamping jaw and the force absorption surface of the clamping and positioning bolt. In contrast, with a circumferential, frustoconical contact recess, there is essentially linear contact between the force absorption surface and the force transmission surface.

[0036] To easily lift the clamping plate from the reference plane plate, lift-off springs, such as disc springs, can be provided in the clamping openings. The lift-off springs press against the clamping and positioning bolts, counteracting the axial force. When the clamping is released and the axial force is thus removed from the clamping and positioning bolts, the lift-off springs push the clamping and positioning bolts, and thus the clamping plate, away from the reference plane plate.

[0037] The clamping device has exactly two clamping jaws, which can be pressed against the clamping and positioning bolts with a single clamping device, as described above. This allows for the creation of a clamping device that requires very few components.

[0038] In a preferred embodiment, the clamping device has a return spring for each clamping jaw, which is operatively connected to its respective clamping jaw in such a way that the clamping jaws are moved towards each other against the restoring force of the return springs. The advantage of this design lies in better haptics. At the stage in which the clamping and positioning bolts are no longer firmly clamped, the clamping device has play according to the invention, and this play increases the further the clamping jaws are moved apart. The return springs ensure that the clamping device always assumes a defined rest position along the movement axis. The return springs preferably extend along the spindle body of the clamping device and are furthermore preferably designed as helical springs with identical spring stiffness.

[0039] Further preferably, the clamping device for one, several, or all of the clamping openings has a lifting spring provided in the opening, which is configured to at least partially push the clamping and positioning bolt out of the clamping opening in the opposite direction to its insertion direction as soon as the clamping state between the clamping jaws and the clamping and positioning bolt is released. The lifting spring is preferably designed as an elastically deformable element, for example, as an elastomer ring or a disc spring.

[0040] In a preferred embodiment, the clamping device has a reference plane plate, two clamping jaws, a clamping means, two return springs (e.g. spiral springs), and a lifting spring (e.g. disc spring) for each clamping opening.

[0041] The particularly simple design and the possible use of standard parts make it possible to manufacture the clamping device particularly cost-effectively.

[0042] The axial forces that press the clamping plate against the reference plane plate run in the direction of the longitudinal axes of the clamping and positioning bolts. They are determined by the second angle formed by the surface normal of the contact surface between the force-transmitting surfaces and force-absorbing surfaces with the reference plane. Furthermore, the radial force is transmitted as a radial force component from the clamping jaws to the clamping and positioning bolts. This force component acts in a radial direction relative to the longitudinal axes of the clamping and positioning bolts and thus parallel to the reference plane. The radial forces can act in the reference plane at a predefined angle to the movement axis A. In a preferred embodiment, the force-transmitting surfaces are provided on beveled edges of the clamping jaws.In this case, the directions of action of the radial forces depend on the first angle, which essentially corresponds to the angle formed by the beveled edges with the axis of movement. The radial forces of a clamping jaw can be parallel to the axis of movement A, converging toward it, or diverging from it.

[0043] Designs with O- or X-shaped (diverging or converging) lines of force have the advantage that the clamping and positioning bolts or the clamping plate are automatically clamped in a centering manner.

[0044] Because a clamping jaw has multiple clamping surfaces, it is possible to clamp different clamping plates in one and the same clamping device, even if the clamping plates have differently spaced clamping and positioning bolts. This increases the flexibility and application possibilities of the clamping device. Each clamping jaw preferably has either two or four force transmission surfaces, with two force transmission surfaces per clamping jaw being assigned to a set of clamping and positioning bolts.

[0045] In a preferred embodiment, the clamping openings or the clamping and positioning bolts can be arranged on a fixed grid. The grid can be square or rectangular. This enables modular application and versatile uses. For example, the clamping plates on the reference plane plate can be rotated by 90° or 180° without great effort. It is also possible for a reference plane plate to have a plurality of clamping openings (more than clamping and positioning bolts per clamping plate) in a corresponding grid, even if the clamping plates used only have four positioning bolts, for example. The position of the clamping plate on the reference plane plate can then be selected in stages. In a preferred embodiment, the grid spacing between the clamping openings is 52 mm and / or 96 mm.If a reference plane plate has clamping openings with different grid spacing to accommodate clamping plates with differently spaced clamping and positioning bolts, these clamping openings can have different diameters to accommodate clamping and positioning bolts with different diameters.

[0046] The clamping device can have a mechanical, pneumatic, hydraulic or electric motor drive.

[0047] In a further preferred embodiment, the clamping device has a housing cover arranged opposite the clamping surface, which is reversibly detachably connected to the clamping device and by means of which the recesses for the clamping jaws and the clamping device are accessible. This embodiment has manufacturing advantages, particularly for clamping devices with a flat design. The recesses for the clamping jaws and clamping device, in particular the drive spindle, are designed as pockets that are closed by the housing cover. Because the housing cover is arranged on the side facing away from the clamping surface, the clamping jaws and the clamping device cannot be accidentally manipulated or removed as long as the clamping device is mounted on a machine tool.

[0048] The invention is explained below using various embodiments, with reference to a drawing. Figure 1.1 shows a first embodiment of a clamping device in a perspective view; Figure 1.2 shows the clamping device from Figure 1.1 in a top view; Figure 1.3 shows the clamping device from Figure 1.1 in a side view; Figure 1.4 shows the clamping device Figure 1.1 in a front view; Figure 1.5 shows the clamping device Figure 1.1 in an exploded view; Figure 1.6 shows an inventive force distribution of the clamping forces in the clamping device; Figure 2.1 shows a second embodiment of a clamping device in a perspective view; Figure 2.2 shows the clamping device from Figure 2.1 in a top view; Figure 2.3 shows the clamping device from Figure 2.1 in a side view; Figure 2.4 shows the clamping device Figure 2.1 in a front view; Figure 3.1 shows an embodiment of a clamping device according to the invention in a perspective view; Figure 3.2 shows the clamping device from Figure 3.1 in a top view; Figure 3.3 shows the clamping device from Figure 3.1 in a side view; Figure 3.4 shows the clamping device from Figure 3.1 in a front view; Figure 4.1 shows an embodiment of the clamping device with a clamping plate with clamping and positioning bolts in a front view; Figure 4.2 shows the clamping device from Figure 4.1 in a top view; Figure 4.3 shows the clamping device from Figure 4.1 in a perspective view; Figure 4.4 shows a detailed view of the clamping device from Figure 4.4 ; Figure 4.5 shows the clamping device from Figure 4.1 in an exploded view; Figure 5 shows a clamping device from the prior art.

[0049] In the Figures 1.1 to 1.5A first embodiment of a clamping device is shown. The upper side of a reference plane plate 10 forms a clamping surface 15, with which a reference plane is defined. The reference plane plate 10 has two recesses 11 for forming guides. The recesses 11 are recessed on opposite sides of the reference plane plate 10. The recesses 11 are connected to four clamping openings 20, which extend from the clamping surface 15 into the reference plane plate 10, orthogonal to the clamping surface 15. The two recesses 11 are connected to one another via a through-bore 13.

[0050] In each of the two recesses 11, a clamping jaw 40 is guided for displacement along a movement axis A. Each clamping jaw 40 has two force transmission surfaces 41. Each force transmission surface 41 is formed by a wedge-shaped projection extending from the clamping jaw 40. The wedge-shaped projections of the clamping jaws 40 forming the force transmission surfaces 41 extend into the clamping openings 20 of the reference plane plate 10 when the clamping jaws 40 are moved towards one another via a clamping device 30. For this purpose, the clamping device 30 is guided through the through-bore 13 of the reference plane plate 10. The clamping device 30 is a bolt having an external thread 31 at one end and a screw head 34 with a hexagon socket 33 at the opposite end. One of the clamping jaws 40a has a through-bore 43 through which the clamping device 30 is guided.The through-bore 43 of the clamping jaw 40a has an enlarged cross-section at both ends of the clamping jaw 40a, so that receiving extensions 45 are formed at both ends. The screw head 34 can be received in the receiving extension 45, which faces outwards with respect to the reference plane plate 10. When the clamping device 30 is tightened, the end of the receiving extension 45 serves as a stop 44 for the screw head 34, so that a force can be transmitted from the clamping device 30 to the clamping jaw 40a. The other receiving extension 45 serves to accommodate a return spring 32, which presses the clamping jaw 40a outwards (i.e., away from the clamping openings 20, out of the recess 11) when the tensile force between the clamping jaws 40 is released by the clamping device 30.

[0051] To accommodate the return springs 32, the through-bore 13 of the reference plane plate 10 also has a receiving extension 45 for the return springs 32 at both ends. Accordingly, a return spring 32 is also provided on the opposite side of the clamping jaw 40b. Analogous to the clamping jaw 40a, the clamping jaw 40b also has a corresponding receiving extension 45 at the passage for the clamping device 30. The passage of the clamping jaw 40b for the clamping device 30 has an internal thread 42 adjacent to the receiving extension 45 for the return spring 32. The internal thread 42 of the clamping jaw 40b engages with the external thread 31 of the clamping device 30, so that rotation of the clamping device 30 causes the clamping device 30 and the clamping jaw 40b to move translationally relative to one another. Since the screw head 34 presses against the other clamping jaw 40a, the clamping jaw 40a also moves relative to the clamping device 30 and the clamping jaw 40b.The clamping jaws 40 are thus moved along a movement axis A, parallel to the reference plane 15. With a right-hand external thread 31, the two clamping jaws 40 are moved toward each other by a clockwise rotation of the clamping device 30, so that spring forces build up in the return springs 32. If the clamping device 30 is conversely rotated to the left, the clamping jaws 40 are pushed apart by the return springs 32.

[0052] The clamping openings 20 have an insertion chamfer 23 on the clamping surface 15 of the reference plane plate 10, so that the clamping and positioning bolts 110 can be more easily inserted into the clamping openings 20 of the reference plane plate 10. Furthermore, the clamping openings 20 have an axial stop 24 on their underside, against which the clamping and positioning bolts 110 can be pressed during clamping in the axial direction. The axial stops 24 are preferably designed as disc springs. Since the stop in the axial direction actually occurs between the clamping surface 15 and the base surface 101, a rigid / inelastic axial stop between the clamping and positioning bolts and the reference plane plate should be avoided. In order to enable easy lifting of the clamping plate 100 from the reference plane plate 10, the clamping plate 100 can be automatically lifted slightly via a spring-loaded axial stop 24 after the clamping device 30 has been released.

[0053] If the clamping and positioning bolts 110 are inserted into the clamping openings 20 and the clamping device 30 is rotated so that the clamping jaws 40 are pulled towards each other, the wedge-shaped projections of the clamping jaws, which form the force transmission surfaces 41, engage in contact recesses 114 provided for this purpose in the clamping and positioning bolts 110, which form the force absorption surfaces 111. Preferably, only the lower surfaces of the wedge-shaped projections and the upper surfaces of the contact recesses 114 are in contact with each other. A second angle, which the contact surfaces between the wedges and the contact recesses 114 enclose with the reference plane 10, results in the proportional distribution of contact forces F Anp into radial forces F rad and axial forces F ax , which are transmitted to the clamping and positioning bolts (as shown in particular in Fig. 1.3 shown).

[0054] Beveled edges of the clamping jaws 40, on which the wedges are arranged, have a first angle to the movement axis A in the illustrated embodiment. The first angle determines how the radial force F rad is divided into a horizontal force F rad1 directed parallel to the movement axis A and a horizontal force F rad2 directed perpendicular to the movement axis A. In the illustrated example, the wedges or force transmission surfaces 41 of the clamping jaws are arranged obliquely to the movement axis A, with a surface normal having a component parallel to the movement axis A towards the center of the reference plane plate and a component perpendicular to it towards the outside of the clamping plate 100. This results in an O-shaped arrangement of the resulting radial forces F rad on the clamping and positioning bolts 110 (see in particular Figure 1.6 ), which has a centering effect on the clamping plate.

[0055] The recesses 11 of the reference plane plate 10 are simple and cost-effective to manufacture since they can be introduced into the reference plane plate 10 from the outside.

[0056] The preferred shape of the reference plane plate 10, which is also illustrated here, is rectangular. The extent of the reference plane 15 (i.e., the length and width of the reference plane plate 10) is significantly larger than the orthogonal thickness of the reference plane plate 10. This allows for sufficient spacing between the clamping and positioning bolts 110, which is necessary to clamp the clamping plate 100 sufficiently firmly and precisely. The side surfaces of the reference plane plate 10 are preferably flat, straight, and arranged at right angles to one another. This facilitates zero point detection using milling machines or similar processing machines.

[0057] The tensile or compressive force F 1 , which is transmitted via the clamping device 30 to the clamping jaws 40, is counteracted by the spring forces of the return springs 32 and the contact forces F Anp of the clamping and positioning bolts.

[0058] As the Figures 2.1-2.4 show, the clamping and positioning bolts 110 do not necessarily have to be arranged symmetrically. In the embodiment shown, the clamping and positioning bolts 110 or the clamping openings are on one side (left in Fig. 2.1 ) at a first distance RA, and the clamping and positioning bolts (or clamping openings) on the other side (right in Fig. 2.1 ) are arranged at a second distance RB, where RB < RA. As a result, the right-hand clamping openings and bolts are offset inward / toward the center of the reference plane plate 10 parallel to the movement axis A. This can be achieved with simple means via a lateral shoulder 46 on the clamping jaws 40.

[0059] In practice, it can be particularly advantageous to be able to offer clamping devices for different clamping plates (100) (from different manufacturers). Therefore, it is advantageous to be able to offer a high degree of flexibility and a wide range of geometries.

[0060] In the Figures 3.1-3.4An embodiment of the invention is shown in which different clamping plates 100 can be clamped with differently spaced clamping and positioning bolts 110. For this purpose, the reference plane plate 10 has two sets of clamping openings 20 in a respective grid. A first set of clamping openings 20a is designed for clamping plates 100 with first spacings RA in a grid RA x RA between the clamping and positioning bolts 110 to be clamped, and a second set of clamping openings 20b is provided for clamping plates 110 with second spacings RB in a grid RB x RB between the clamping and positioning bolts 110. In the embodiment shown, the first spacings RA both between the first clamping openings 20a parallel to the movement axis A and orthogonal to the movement axis A are higher than the second spacings between the second clamping openings 20b.Furthermore, in the illustrated embodiment, both sets of clamping openings 20a, 20b have different diameters of the clamping openings 20. Thus, not only clamping plates 100 with differently spaced clamping and positioning bolts 110 can be used, but also clamping plates with clamping and positioning bolts 110 of different diameters. As an alternative to the illustrated embodiment, it is also possible for the clamping openings 20a of the first set of clamping openings to be spaced closer together in only one direction (i.e., either in a direction parallel to or orthogonal to the movement axis A) than the clamping openings 20b of the second set of clamping openings.

[0061] In the example shown, the clamping jaws 40 are constructed in a stepped manner. A first step 46 has two first force transmission surfaces 41a on two first beveled edges with two first wedges that can be brought into contact with force-absorbing surfaces of the first set of clamping and positioning bolts. A second step 47 has two second force transmission surfaces 41b on two second beveled edges with two second wedges that can be brought into contact with force-absorbing surfaces 111 of the second set of clamping and positioning bolts 110. The first step 46 is offset along the direction of the movement axis A from the second step 47 toward the center of the reference plane plate 10.

[0062] When the first set of clamping and positioning bolts is used, the first force transmission surfaces 41a of the first stage 46 of the clamping jaws 40 come into contact with the force absorption surfaces 111 of the first set of clamping and positioning bolts 110. The second force transmission surfaces 41b of the second stage 47 of the clamping jaws 40 are not in any contact with the clamping and positioning bolts 110. The beveled edges of the second stage 47 of the clamping jaws 40 engage the empty clamping openings 20b of the second set of clamping openings 20b. Thus, there is sufficient play to generate the required force on the first set of clamping and positioning bolts 110.

[0063] When the second set of clamping and positioning bolts 110 is used, the second force transmission surfaces 41b of the second stage 47 of the clamping jaws 40 come into contact with the force absorption surfaces 111 of the second set of clamping and positioning bolts 110. The first force transmission surfaces 41a of the first stage of the clamping jaws 40 are not in any contact with the clamping and positioning bolts 110. The beveled edges of the first stage 46 of the clamping jaws 40 engage in the empty clamping openings of the first set of clamping openings 20a. Thus, there is sufficient play to generate a required force on the second set of clamping and positioning bolts 110.

[0064] The clamping openings 20 that are not in use can be closed by means of caps to prevent chips or other contaminants from entering the clamping openings 20.

[0065] In the Figures 4.1 to 4.5a clamping device including the clamping plate 100 with the clamping and positioning bolts 110 is shown.

[0066] The clamping and positioning bolts 110 can be connected to the clamping plate 100 in a force-locking, form-locking, or material-locking manner. In the illustrated case, the clamping and positioning bolts are connected to the clamping plate 100 via a threaded connection. As shown in particular in the Figures 4.2 and 4.3As can be seen, the clamping and positioning bolts have some play relative to the clamping openings 20 of the reference plane plate. This facilitates the insertion of the clamping and positioning bolts into the clamping opening 20. If the clamping jaws 40 are tightened via the clamping device 30, the positioning surfaces 113 of the clamping and positioning bolts 110 are pressed against the reference surfaces 22 of the wall 21 of the reference plane plate 10. For this purpose, the wedge-shaped projections of the clamping jaws 40 engage in the wedge-shaped contact recesses 114 of the clamping and positioning bolts 110, so that the force transmission surfaces 41 come into contact with the force absorption surfaces 111 of the clamping and positioning bolts 110. An axial stop 112 of the clamping and positioning bolts presses against an elastic axial stop 24 at the lower end of the clamping opening 20. By tightening the clamping jaws, the clamping and positioning bolts and the clamping plate 100 are pulled slightly downwards.Thus, a force is stored in the lower axial stop 24 of the clamping opening 20, and the base surface 101 of the clamping plate 100 is pressed against the clamping surface 15 of the reference plane plate 10. If the clamping jaws 40 are released, the elastic axial stop pushes the clamping and positioning bolts, and thus also the clamping plate 100, upwards again. In the illustrated case, the wedge-shaped contact recess 114 of the clamping and positioning bolts 110 is designed to be circumferential. Alternatively, the clamping and positioning bolts 110 can also have tangentially extending recesses on one or more sides.

[0067] Figure 5shows a prior art clamping device for the purpose of explanation. A clamping device 230 generates a compressive force FS1, which is transmitted via several transmission bolts 231a, 231b, 240a, 240b, 240c, 240d to the clamping bolts of a clamping plate located in the clamping openings 220. This creates a contact or force transmission surface between the clamping device 230 and the transmission bolts 240a, 240b, 240c, and 240d. At each of the transmission surfaces, there is the possibility of jamming or tensioning of the engaging elements. Furthermore, a force loss occurs due to friction. The force is transmitted at a 90° angle, so that the radial forces act on the clamping bolts parallel to the axis of the clamping device 230 and to the applied compressive force F201. Accordingly, the forces are redirected twice before they are transferred to the clamping bolts.Compressive force F 201 is divided into the transmission forces F 202, and the transmission forces F 202 are divided into the transmission forces F 203. Jamming / tilting / tensioning can also easily occur at the clamping bolts in the form shown, since the clamping bolts are pressed parallel to one another against the walls of the clamping openings 220. Since the radial forces acting on the clamping bolts are parallel, no automatic centering takes place. This is prevented by an inventive division of the radial forces into longitudinal and transverse components, as shown, for example, in . Figure 1.6 The force alignment results in the clamping and positioning bolts being automatically centered. Fig. 5The clamping device shown requires many individual transmission bolts and holes, which makes production and assembly complex and expensive, and does not allow the use of different clamping plates as with a clamping device according to Fig. 3.1 to 3.4 because the transmission bolts 240a, 240b, 240c and 240d have a single fixed length.

[0068] In the figures described above, pocket-like recesses are provided on the sides of each clamping device, into which the clamping jaws and the clamping means are inserted. This type of assembly is particularly suitable for clamping devices with a tall design. For clamping devices with a flat design, such as the designs shown here, it is alternatively also preferred to arrange the recesses of the clamping jaws so far away from the clamping surface that the recesses are accessible by opening a housing cover on the side opposite the clamping surface. The clamping jaws and the clamping means, in particular a spindle, can then be pre-assembled and simply inserted into the recesses before the housing cover is closed.The geometric conditions of the figures shown are otherwise not affected by this, so that with the exception of the housing cover not shown, the above also applies accordingly to such a preferred embodiment. List of reference symbols

[0069] 10 Reference plane plate 11 Recess 13 Through hole 15 Clamping surface / reference plane 20 Clamping opening 20a First set of clamping openings 20b Second set of clamping openings 21 Wall 22 Reference surface 23 Lead-in chamfer 24 Axial stop 30 Clamping device 31 Force converter / external thread / thread 32 Force accumulator / return spring 33 Force connection point / octagonal socket 34 Screw head / stop 40 / 40a / 40b Clamping jaws 41 Force transmission surface 41a First force transmission surface 41b Second force transmission surface 42 Force converter / internal thread / counter thread 43 Through hole 44 Stop surface 45 Mounting extensions 46 Side shoulder 47 First step 48 Second step 50 Tightening device 100Clamping plate 101Base area 110Clamping and positioning bolts 111Force absorption surfaces 112Axial stop 113Positioning surface 114(Wedge-shaped) contact recess 220Clamping opening 230Clamping device 231a, 231bTransmission bolt 240a - 240dTransmission bolt AMovement axis F 1 Tensile / compressive force F anp Contact force F ax Axial force F rad Radial force F rad1 , F rad2 Radial force component F 201 Compressive force F 202 Transmission force F 203 Transmission force

Claims

1. Clamping device, in particular for clamping workpieces for machining, comprising a reference plane plate (10) which has a planar clamping surface (15), which defines a reference plane, and at least two clamping openings (20) with walls (21), on which at least one reference surface (22) is respectively formed, the clamping device serving to clamp a clamping plate (100) which has a planar base surface (101) which can be placed on the clamping surface (15), and comprising at least two clamping and positioning bolts (110) associated with the clamping openings (20) and respectively comprising a positioning surface (113) associated with the reference surfaces (22), and comprising a tightening device (50) which is equipped to apply an axial force (Fax) and a superimposed radial force (Frad) to the clamping and positioning bolts (110), wherein the base surface (101) of the clamping plate (100) can be pressed against the clamping surface (15) of the reference plane plate (10) by means of the axial force (Fax), and the clamping and positioning bolts (110) with their positioning surfaces (113) can be pressed against the reference surfaces (22) by means of the radial force (Frad), wherein the tightening device (50) has two clamping jaws (40) and a clamping means (30), wherein a force transmission surface (41) is provided on one of the clamping jaws (40) for each clamping and positioning bolt (110), wherein each clamping and positioning bolt (110) has a force receiving surface (111) for interacting with one of the force transmission surfaces (41), wherein the force transmission surfaces (41) of the clamping jaws (40) can be brought into contact with the force receiving surfaces (111) of the clamping and positioning bolts (110) and by this means the axial forces (Fax) and the radial forces (Frad) can be applied to the clamping and positioning bolts (110), wherein the clamping means (30) and the clamping jaws (40) can be displaced along a single, defined movement axis (A), characterized in that the clamping device a first set of clamping openings (20a) for receiving the clamping and positioning bolts (110) of a first clamping plate (100) with first distances between the clamping and positioning bolts (110), and has a second set of clamping openings (20b) for receiving the clamping and positioning bolts (110) of a second clamping plate (100) with second distances between the clamping and positioning bolts (110), wherein the first distances and the second distances are different, wherein both clamping jaws (40) respectively have four force transmission surfaces (41), wherein two first force transmission surfaces (41) of each clamping jaw (40) can respectively be brought into contact with the force receiving surfaces (111) of the clamping and positioning bolts (110) of the first clamping plate (100) when the clamping and positioning bolts (110) of the first clamping plate (100) are engaged with the first set of clamping openings (20a), and two second force transmission surfaces (41) of each clamping jaw (40) can respectively be brought into contact with the force receiving surfaces (111) of the clamping and positioning bolts (110) of the second clamping plate (100) when the clamping and positioning bolts (110) of the second clamping plate (100) are engaged with the second set of clamping openings (20b).

2. Clamping device according to claim 1, wherein the clamping means is in direct and exclusive operative connection with the clamping jaws in order to move these toward one another or away from one another.

3. Clamping device according to one of the preceding claims, characterized in that the reference plane plate (10) has the first set of clamping openings (20) in a first grid with a grid spacing RA x RA, and the second set of clamping openings in a second grid with a grid spacing RB x RB, wherein the grid spacing RB x RB of the second grid differs from the grid spacing RA x RA of the first grid.

4. Clamping device according to one of the preceding claims, characterized in that the clamping means (30) has a force generating means (31), wherein a compressive force and / or a tensile force (F1) can be caused by means of the force generating means (31).

5. Clamping device according to one of the preceding claims, characterized in that the force generating means (31) is a threaded arrangement or a fluid-actuated piston-cylinder assembly or an electromechanical assembly.

6. Clamping device according to one of the preceding claims, wherein the force generating means is designed as a spindle which has at least one thread and is operatively connected to both clamping jaws in such a way that a rotation of the spindle causes a movement of the clamping jaws toward one another or away from one another in the direction of the movement axis.

7. Clamping device according to claim 6, wherein the spindle has a spindle body, on whose one end the thread is arranged which engages with a thread of the first clamping jaw, and on whose opposite end a head section is designed, which has an increased diameter relative to the spindle body and contacts the second clamping jaw with a contact surface.

8. Clamping device according to claim 6, wherein the spindle has a spindle body, on whose one end a first thread is arranged which engages with a thread of the first clamping jaw, and on whose opposite end a second, reverse pitch thread is arranged which engages with a thread of the second clamping jaw.

9. Clamping device according to one of the preceding claims, characterized in that the clamping and positioning bolts (110) are not oversized with respect to the clamping openings (20), but instead are preferably undersized, wherein the clamping and positioning bolts (110) are preferably designed as elastically resilient with respect to their radial direction, and / or the maximum spring deflection of the clamping and positioning bolts (110) is greater than the distance of the positioning surfaces (113) of the clamping and positioning bolts (110) from the reference surfaces (22) .

10. Clamping device according to one of the preceding claims, wherein the force transmission surfaces and the force receiving surfaces are in contact with one another in the clamped state, wherein a force, oriented in the direction of a surface normal of the contact surface, can be transmitted to the contact surface, wherein the force is the vector sum of a radial force and an axial force, wherein the force defines a first angle with a vertical plane arranged parallel to the movement axis and orthogonal to the reference plane, and defines a second angle with the reference plane, wherein the first angle is preferably between 20º and 70º and / or the second angle is preferably between 20º and 70º.

11. Clamping device according to one of the preceding claims, wherein the clamping device has a return spring for each clamping jaw, said return spring being operatively connected to its respective clamping jaw in such a way that the clamping jaws are moved toward one another against the reset force of the return spring.

12. Clamping device according to one of the preceding claims, wherein the clamping device has a lifting spring provided in the opening for one, multiple, or all of the clamping openings, said lifting spring is equipped to press the clamping and positioning bolt counter to its insertion direction at least partially out of the clamping opening as soon as the clamping state between the clamping jaws and the clamping and positioning bolt is released.

13. Clamping device according to one of the preceding claims, wherein the clamping device has a recess for each of the clamping jaws, in which recess the clamping jaws are respectively movably guided in the direction of the movement axis (A), in particular mounted so as to slide, and a continuous recess for the clamping means, in which continuous recess the clamping means is positioned without contact.

14. Clamping device according to claim 13, wherein the clamping device has a housing cover, arranged opposite the clamping surface, connected in a reversibly detachable manner to the clamping device, and by means of which the recesses for the clamping jaws and the clamping means are accessible.