Abstract
A clamping device for clamping or gripping an object comprising a basic body which comprises an interface for the connection to a working or testing device, the basic body extending along a central axis and comprising at least four guides disposed opposite of each other in pairs which extend radial to the central axis, and at least four clamping elements respectively one of which, at least in portions, is introduced into a guide, the guide supporting and guiding the clamping element radial to the central axis with a linear degree or freedom, and the clamping element having at least one coupling surface which is oriented so that it is inclined with respect to the central axis.
Claims
1. A clamping device for clamping or gripping an object comprising a basic body which includes an interface for the connection to a working or testing machine, wherein the basic body extends along a central axis and includes at least four guides disposed opposite of each other in pairs which extend radial to the central axis, at least four clamping elements respectively one of which, at least in portions, is introduced into a guide, wherein the guide supports and guides the clamping element radial to the central axis with a linear degree or freedom, and the clamping element has at least one coupling surface which is oriented so that it is inclined with respect to the central axis, at least two coupling elements each of which is kinematically coupled to two clamping elements disposed opposite of each other radial to the central axis, wherein the coupling element comprises two transmission elements spaced apart from each other radial to the central axis which, at least in portions, extend tangential to the circumferential direction around the central axis, wherein each transmission element is or can be brought in contact with a coupling surface of a clamping element, and wherein the two coupling elements are supported in or on the basic body so that they are independently movable in a direction parallel to the central axis, at least two activation elements each of which is connected to one of the coupling elements, wherein the activation elements are arranged so that they are independently movable relative to the basic body at least in a direction parallel to the central axis, wherein, during a movement of an activation element in the direction of the central axis, the coupling element connected thereto also moves in the direction of the central axis and the interaction of the two transmission elements of the coupling element and respectively one coupling surface of a clamping element translates the movement of the coupling element into a movement of two clamping elements arranged opposite of each other radial to the central axis in the direction radial to the central axis.
2. The clamping device according to claim 1, wherein the guide has a cavity for accommodating a clamping element, wherein at least one insertion element is provided which protrudes into the cavity and is provided for the engagement in a clamping element to fix the clamping element in a direction parallel to the central axis, wherein the clamping element is movable radial to the central axis, and/or the clamping element, at least in portions, has a disk-shaped design and is introduced into a cavity disposed in the guide in sliding fit, and/or the coupling surface is disposed in a recess in the clamping element which, at least partly, extends through the clamping element tangential to the circumferential direction around the central axis.
3. The clamping device according to claim 1, wherein the coupling element, in portions, has a fork-shaped design, wherein at least two supports spaced apart from each other radial to the central axis are provided which, at least in portions, extend parallel to the central axis, wherein a central portion is disposed between the supports and connects the supports, and each support supports a transmission element, wherein a distance is present between the connection of the central portion to the supports and the connection of the transmission elements to the supports.
4. The clamping device according to claim 1, wherein a compensation mechanism is provided which is connected to the activation elements, wherein the compensation mechanism is provided to compensate a difference in the position of the coupling elements in the direction of the central axis and therefore a difference in the distance between clamping elements disposed opposite of each other radial to the central axis.
5. The clamping device according to claim 4, wherein the compensation mechanism comprises at least two transmission members which respectively extend along a member axis, wherein each transmission member is rotatably connected to an activation element at a first end, and the transmission members are rotatably connected to each other and connected to the sliding element so that they are linearly shiftable relative to the sliding rail at a second end disposed opposite of the first end in the direction of the member axis.
6. The clamping device according to claim 5, wherein the transmission members are implemented as plane disks and have a bore on the first end and on the second end, respectively, and the bores on the first end are respectively connected to an activation element by means of a bolt, and the bores on the second end are connected to each other by means of a bolt, wherein the bolt which connects the two second ends to each other protrudes into the sliding rail in sliding fit.
7. The clamping device according to claim 4, wherein the central portion has an internal guide, wherein a guiding spike is introduced through the internal guide of the central portions of the two coupling elements in sliding fit and guides the two coupling elements relative to each other in the direction of the central axis, wherein the guiding spike is connected to the sliding element and extends parallel to the central axis.
8. A testing device for optically inspecting or measuring an object, wherein the testing device comprises at least one object receptacle rotatable about at least one axis of rotation, wherein the object receptacle comprises at least one clamping device according to claim 1, wherein the central axis of the clamping device is oriented coaxial to the axis of rotation, wherein at least one camera unit is provided which includes at least one camera which is directable towards an object clamped in the clamping device, wherein the camera transmits captured images to a calculating unit which is configured to calculate a volume model from a plurality of images and to inspect or measure the volume model according to at least one test specification.
9. The testing device according to claim 8, wherein the testing machine rotates the object receptacle including the clamping device and the object clamped therein about the axis of rotation, wherein the camera captures a plurality of images of the object in various rotational positions about the axis and transmits them to the calculating unit.
10. A method for measuring an object using a testing device according to claim 8 comprising the process steps of: A) clamping an object to be measured between the clamping elements of the clamping device, B) rotating the object receptacle about the axis of rotation, wherein the camera captures a plurality of images of the object accommodated in the clamping device during the rotation, C) transmitting the images from the camera to the calculating unit, D) calculating a volume model of the object based on the images by the calculating unit, E) measuring the volume model, wherein the measurement takes place based on at least one test specification already stored or input by an operator.
11. The clamping device according to claim 4, wherein the compensation mechanism is connected to an actuator via a sliding element, wherein the sliding element is movable in the direction of the central axis by the actuator.
12. The clamping device according to claim 11, wherein the sliding element comprises at least one sliding rail which is formed by a recess in the sliding element, wherein the sliding rail extends perpendicular to the central axis.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0071] In the Figures, embodiments of the invention are schematically illustrated. Here,
[0072] FIG. 1 shows a perspective view of a first embodiment of a clamping device according to the invention,
[0073] FIG. 2 shows a perspective view of the components of the first embodiment of FIG. 1 disposed within the basic body,
[0074] FIG. 3 shows a perspective view of the first embodiment of FIG. 1 with components partly removed,
[0075] FIG. 4 shows a perspective view of a second embodiment of a clamping device according to the invention,
[0076] FIG. 5 shows a perspective view of the components of the second embodiment of FIG. 4 disposed within the basic body,
[0077] FIG. 6 shows a perspective view of a subsection the components of the second embodiment of FIG. 4 disposed within the basic body,
[0078] FIG. 7 shows a perspective view of the second embodiment illustrated in FIGS. 4, 5, and 6 including a guiding spike.
DETAILED DESCRIPTION
[0079] In the Figures, identical elements are designated by the same reference numerals. Generally, the described properties of an element described with reference to one Figure also apply to the other Figures. Directional information such as above or below refer to the described Figure and are to be applied to other Figures according to their meaning.
[0080] FIG. 1 shows a perspective view of a first embodiment of a clamping device 1 according to the invention. In the illustrated first embodiment, the two pairs of clamping elements 12 disposed opposite of each other are respectively movable in a direction radial to the central axis MA by a separate actuator A. The length of the clamping device 1 in the direction of the central axis MA is small, and the clamping device I has a simple design and therefore also a low weight due to a small number of components. The basic body 11 extends along the central axis MA and supports or accommodates the other components in its interior. On the end facing downwards, an interface 111 implemented as a cylindrical pin for the connection to a device, for example, a testing device is disposed. On the face side of the basic body 11 facing upwards, four guides 112 are disposed which extend radial to the central axis MA. Respectively two of these guides 112 are disposed opposite of each other with respect to the central axis MA. The guides 112 are respectively offset by 90 with respect to each other in the circumferential direction around the central axis. In each of the guides 112, a disk-shaped clamping element 12 is integrated. The guides 112 are implemented as grooves in the basic body 11 which transition into the receiving space 113 in the centre. The receiving space 113 is implemented as a hollow space which is provided to accommodate a subsection of an object to be clamped. In a plan view from the direction of the central axis MA, the receiving space 113 has a square cross section. The clamping elements 12 are supported in the respective guides 112 so that they are linearly movable radial to the central axis MA. This support is formed by the grooves which form cavities in the basic body 11. Details of the clamping elements 12 and the guides 112 are illustrated in FIG. 2. The clamping device I comprises two coupling elements 13a and 13b respectively one of which is kinematically coupled to two clamping elements 12 disposed opposite of each other. This kinematic coupling is established by respectively two transmission elements 131 associated with a coupling element 13a, 13b which are in operational connection with respectively one coupling surface 121 of a clamping element 12. Details of this operational connection are illustrated a FIG. 2. The upper ends of the coupling elements 13a, 13b which can be seen in FIG. 1 are respectively disposed adjacent to a guiding edge of a guide 112. The guiding edge defines the cavity of the guide into which the clamping element 12 is movably introduced. The guiding edge projects beyond adjoining portions of the basic body 11 which are oriented perpendicular to the central axis MA. The projecting guiding edge renders the easy arrangement of recesses possible which extend tangential to the circumferential direction around the central axis MA. These recesses can be used for passing-through an insertion element 1121 or a transmission element 131. In the illustrated embodiment, the guiding edge of each guide 122 has recesses disposed at a distance from each other in the radial direction to the central axis for introducing and fixing respectively one insertion element 1121. The insertion elements 1121 are pressed into these recesses. The insertion elements 1121 and their connection to the guide element 12 can be seen in FIG. 2. The guiding edge of each guide 112 further includes a recess which is provided for passing-through a transmission element 131 towards the guide element 12. This recess is formed by an elongated hole which extends through both guiding edges associated with a guide 112 tangential to the circumferential direction to the central axis, the longer side of this elongated hole being oriented parallel to the central axis MA. In this way, this elongated hole guides the transmission element 131 connected to a coupling element 13a, 13b in the direction of the central axis MA. In the illustrated embodiment, the disk-shaped clamping elements 12 are introduced into respectively one guide 112 in sliding fit. In the illustrated first embodiment, the clamping device comprises two actuators A which, in portions, are disposed in the interior of the basic body 11. These actuators A are in operational connection to the activation elements 14a, 14b disposed in the interior which are illustrated in FIG. 2. Each actuator A comprises a nut supported so that it is rotatable about the central axis MA and including a female thread. This nut is knurled on its outer circumference and can therefore be rotated relative to the central axis MA in a simple manner with the aid of the fingers. The nut is supported in the basic body 11 so that it is linearly immobile in the direction of the central axis MA. As a result of a rotation of the nut, the activation element 14a, 14b and with it the coupling element 13a, 13b is set into a linear movement parallel to the central axis MA by an interaction of its female thread with a male thread on the activation element 14a, 14b. In the illustrated embodiment, the two coupling elements 13a, 13b can respectively be independently moved by a separate actuator A in this way so that, indirectly, one of the two pairs of clamping elements 12 disposed opposite of each other can be moved towards or away from the central axis in the radial direction by an operation the two actuators.
[0081] FIG. 2 shows a perspective view of the components of the first embodiment of FIG. 1 disposed within the basic body 11. In the illustration of FIG. 2, the basic body 11 and the two actuators A which can be seen in FIG. 1 are not illustrated. In this way, the components illustrated in the interior of the basic body 11 can be seen more readily. Disposed opposite of each other in pairs, respectively, the four clamping elements 12 can be seen. Each of these clamping elements 12 has three continuous recesses which extend completely through the clamping element 12 tangential to the circumferential direction around the central axis MA. The respectively central recess is implemented as an elongated hole the longer side of which is oriented so that it is inclined, particularly at an acute angle, with respect to the central axis MA. The inner surfaces of the elongated hole on the longer sides respectively form a coupling surface 121. Therefore, in this embodiment, each clamping element comprises two coupling surfaces 121 arranged parallel to each other and disposed opposite of each other. Two other recesses in each clamping element 12 respectively form a guide recess 122. These guide recesses 122 are also formed by elongated holes, respectively, the longer side, however, being oriented radially and therefore at right angles to the central axis MA in these elongated holes. The guide recesses 122 serve to guide the clamping element 12 radial to the central axis MA but to fix it parallel to the central axis MA in the respective guide 112. To this end, respectively two insertion elements 1121 which also extend through a guide recess 122, respectively, are introduced through the two guiding edges per clamping element 12 which are disposed opposite of each other with respect to a clamping element 12. The insertion elements 1121 are implemented as cylindrical pins and fixed in a cylindrical bore in each guiding edge by press fitting. Each insertion element 1121 projects into one of the guide recesses 122 in sliding fit. This combination of insertion elements 1121 and a guide recess 122 results in that the clamping elements 12 can linearly move relative to the insertion elements 1121 in the longitudinal direction of the guide recesses 122 implemented as elongated holes and therefore radial to the central axis MA. However, movements in other directions or rotations of the clamping elements 12 relative to the basic body 11 are prevented by this combination. It is also possible to realise a radially movable support of the clamping elements 12 relative to the basic body 11 in another way. The interaction of the recesses and the coupling surfaces 121 and the transmission elements 131 functions in a similar manner: Between respectively two opposing supports 132 of a coupling element 13a, 13b, respectively one transmission element 131 implemented as a cylindrical pin is fixedly introduced. Between the supports 132, the transmission element 131 is guided in sliding fit in the central recess in the clamping element 12 which comprises the coupling surfaces 121. Therefore, the transmission element 131 is shiftable parallel to the coupling surfaces 121 inside the central recess. When a transmission element 131, guided by a coupling element 13a, 13b and/or a recess in the guiding edges, is moved parallel to the central axis MA the clamping element 12 slides along the transmission element 131 parallel to the coupling surface 121. In this way, the movement of the transmission element 131 oriented parallel to the central axis MA is translated into a movement of the clamping element 12 oriented radial to the central axis MA by the inclined coupling surfaces 121. In the illustrated embodiment, the coupling elements 13a, 13b are respectively implemented so that they are rigid and comprise an integral basic body into which the transmission elements 131 implemented as cylindrical pins are introduced in press fit. In the illustrated embodiment, the two coupling elements 13a, 13b are formed so that they are substantially symmetrical to the central axis MA but different from each other in their shape. The coupling elements 13a, 13b, in portions, interpenetrate or engage around each other and are therefore, at least in portions, insertable into each other in the direction of the central axis MA. In this way, an independent movement of the coupling elements 13a, 13b in the direction of the central axis MA is rendered possible without a collision taking place. The coupling elements 13a, 13b have a fork-shaped design in their subsection facing upwards and respectively comprise four supports 132 extending in the direction of the central axis MA in the illustrated embodiment. These supports 132 are spaced apart from each other radial to the central axis MA or tangential to the circumferential direction around the central axis MA. Respectively two supports 132 which are spaced apart from each other tangential to the circumferential direction around the central axis MA carry a transmission element 131. On the side of the supports 132 disposed opposite of the transmission elements 131, they are connected by a central portion 133 which is oriented perpendicular to the central axis MA. On each of the supports 132, a plurality of sliding surfaces 1321 is disposed which are arranged on the outer circumference of each support 132. These sliding surfaces 1321 abut on subsections of the basic body 11 and, together with these, form a sliding bearing of the coupling elements 13a, 13b in the basic body 11 in the direction of the central axis. Such a sliding bearing is readily realisable and benefits a compact design with low requirements on installation space. The distance between supports 132 disposed opposite of each other in the direction radial to the central axis is identical in two coupling elements 13a, 13b. In the illustrated first embodiment, the two activation elements 14a, 14b are respectively formed by subsections of the coupling elements 13a, 13b. Each activation element 14a, 14b is formed by a subsection of a coupling element 13a, 13b projecting in a direction radial to the central axis MA on which a male thread is disposed which extends along the central axis MA. In the mounted state of the clamping device 1, this male thread is in engagement with a female thread which is disposed in the nut of an actuator A. The activation element 14a, 14b is moved in the direction parallel to the central axis MA by a rotation of the nut, this movement being directly transmitted to the coupling element 13a, 13b. The activation elements 14a, 14b are spaced apart from the transmission elements 131 in the direction of the central axis MA. As an alternative to the illustrated embodiment, the coupling elements 13a, 13b may also be assembled from a plurality of individual components. For a compact design having small dimensions, particularly for a clamping device 1 for small, delicate parts, the illustrated integral embodiment is advantageous. If the clamping device 1 has larger dimensions, a multi-part design of the coupling elements 13a, 13b is recommendable.
[0082] FIG. 3 shows a perspective view of the first embodiment of FIG. 1 with components partly removed. FIG. 3 serves the illustration of the operating principle of the actuators A. In FIG. 3, the first embodiment of a clamping device 1 of FIG. 1 is illustrated. However, the lower actuator A as well as a coupling element 13a and an activation element 14a were removed in the illustration of FIG. 3 so that these components are not illustrated. In this way, the remaining coupling element 13b and the remaining activation element 14b can be seen in the mounting position in the interior of the basic body 11. In the interior of the basic body 11, there is a hollow space in which the coupling elements 13a, 13b as well as the activation elements 14a, 14b have sufficient free space to be capable of moving in the direction of the central axis MA. The male thread of the activation element 14b protrudes beyond the coupling element 13b towards the outside in a direction radial to the central axis MA. Below the illustrated, knurled nut of the first actuator A, an identical nut is incorporated which has a female thread which comes into engagement with the male thread on the activation element 14b during the assembly of the clamping device 1. The nuts of the two actuators A are immobile in the basic body 11 in the direction of the central axis MA but supported so that they are rotatable about the central axis MA. During a rotation of the nut of an actuator A, it remains in its position in the basic body 11, and a linear movement of the associated coupling element 13a, 13b in the direction of the central axis MA is induced by means of the interaction of the threads. In the illustrated embodiment, the actuators A are therefore disposed outside of the coupling elements 13a, 13b in the radial direction, but parallel thereto in the direction of the central axis MA. This results in a compact length of the clamping device 1 in the direction of the central axis MA which benefits a good concentricity of the clamping device 1 and therefore of an object clamped in the clamping device 1. With regard to components not described in connection with FIG. 3, the description relating to FIGS. 1 and 2 is made reference to.
[0083] FIG. 4 shows a perspective view of a second embodiment of a clamping device 1 according to the invention. The illustrated second embodiment comprises a compensation mechanism 15 not visible in FIG. 4 which couples the movements of clamping elements 12 arranged opposite of each other to each other in a compensating manner. The second embodiment comprises only one actuator A which serves to operate the clamping device I when clamping or unclamping an object. The basic body 11 of the second embodiment is identical in design to the first embodiment illustrated in FIG. 1 on the face side facing upwards and with respect to the shape and the position of the interface 111 in the area of the guides 112. Therefore, for these subsections of the basic body 11, the description relating to FIG. 1 is made reference to. The central portion of the basic body 11 comprises two openings which render an accessibility of the actuator A in the interior of the basic body 11 possible. In this embodiment as well, the actuator A comprises a nut having a knurled outer circumferential surface which has a female thread in its interior which is in operational connection to a subsection of the compensation mechanism 15.
[0084] FIG. 5 shows a perspective view of the components of the second embodiment of FIG. 4 disposed within the basic body 11. In FIG. 5, the basic body 11 illustrated in FIG. 4 is not illustrated. The components disposed, at least in portions, in the interior of the basic body 11 are partly identical to the first embodiment. The four clamping elements 12 including their recesses and support are identical to the first embodiment. Further, the upper subsections of the coupling elements 13a and 13b including the supports 132 and the transmission elements 131 are identical to the first embodiment. With regard to the details as well as the operating principle and the support of these components in the basic body 11, therefore, the description relating to the first embodiment of FIGS. 1 and 2 is made reference to. In the second embodiment, the coupling element 13a is implemented so that it is longer than in the first embodiment in the direction of the central axis MA. In the second embodiment, the two coupling elements 13a, 13b have a substantially identical length in the direction of the central axis. This is required for the connection to the compensation mechanism 15 disposed below them. In the second embodiment, the two activation elements 14a and 14b are different in design as compared to the first embodiment and arranged in another position relative to the coupling elements 13a, 13b. In the second embodiment, the activation elements 14a and 14b are implemented as subsections of the coupling elements 13a and 13b. The activation elements 14a, 14b are located on the side of the coupling elements 13a, 13b disposed opposite of the transmission elements 131 in the direction of the central axis MA and extend away from the coupling elements 13a, 13b in the direction of the central axis MA. Each activation element 14a, 14b has two subsections disposed parallel to each other and spaced apart from each other. Into the distance between these subsections, a transmission member 152 can be introduced, respectively. The shape of the activation elements 14a, 14b can be seen more readily in FIG. 6. The clamping device 1 according to the second embodiment comprises a compensation mechanism 15 which is, on the one hand, connected to the activation elements 14a, 14b and, on the other hand, to an actuator A. The compensation mechanism 15 is provided to compensate a difference in the position of the coupling elements 13a, 13b in the direction of the central axis MA. Such a difference in the position of the coupling elements 13a, 13b occurs when the clamping elements 12 kinematically coupled thereto abut on an object to be clamped having an irregular cross section. For example, if an object having a square cross section is introduced into the receiving space 113 one pair of opposing clamping elements 12 will abut on the object before the other pair of clamping elements 12 abuts on the object during a movement of the clamping elements 12 radial to the central axis MA towards the inside. In this case, the pair of clamping elements 12 not yet in abutment can move further towards the object until this pair of clamping elements 12 is also in abutment. In the interval in which the first pair of clamping elements 12 is already in abutment but the second pair of clamping elements 12 can still move inwards, the coupling element 13a, 13b which is coupled to the clamping elements 12 still moving moves further along the central axis MA. Therefore, the position of the one coupling element 13a, 13b relative to the position of the other coupling element 13a, 13b changes until the second pair of clamping elements 12 is in abutment. In order to be capable of moving the other pair of clamping elements 12 further towards the object after the first pair of clamping elements 12 abuts on the object, the compensation mechanism 15 is provided. The compensation mechanism 15 renders the autonomous, centred clamping of an object having an irregular cross section between the four clamping elements 12 by an operation of a single actuator A possible. Particularly in the second embodiment including the compensation mechanism 15, operating the clamping device 1 is extremely easy and, due to the autonomous centration, results in reproducible results even in case of a repeated clamping of the same object in the clamping device 1. The compensation mechanism is disposed on the side of the coupling elements 13a, 13b disposed opposite of the clamping elements 12 in the direction of the central axis MA. The compensation mechanism 15 comprises a sliding element 151 which is connected to the actuator A disposed below it. For this purpose, a subsection of the sliding element 151 is implemented as a threaded bolt having a male thread which extends away from the coupling elements 13a, 13b along the central axis MA. The actuator A comprises a nut knurled on its outer circumference which has a female thread in its interior. The male thread of the threaded bolt is introduced into the female thread of the nut. When the nut is rotated about the central axis MA, this rotation is translated into a movement of the sliding element 151 along the central axis MA by the interaction the threads. For this purpose, the nut is rotatable in the basic body 11 but supported so that it is linearly immobile in the direction of the central axis MA. In the sliding element 151, a sliding rail 1511 is integrated which is formed by a recess which extends through the sliding element 151 in a direction perpendicular to the central axis MA. The sliding rail 1511 is implemented as an elongated hole the longer side of which is oriented perpendicular to the central axis MA. In the illustrated embodiment, the sliding rail 1511 extends completely through the sliding element 151 and is accessible from two opposite sides in this way. Alternatively, it is possible that the sliding rail 1511 extends only partly through the sliding element 151. The compensation mechanism 15 further comprises at least two transmission members 152 which movably connect the activation elements 14a, 14b to the sliding element 151. In the illustrated embodiment, the compensation mechanism 15 comprises altogether four transmission members 152 only two of which, however, are illustrated or to be seen. In the illustrated embodiment, the transmission members 152 are implemented as planar disks and formed similar to chain links. Each transmission member 152 extends in the longitudinal direction along a member axis. Each transmission member 152 has a bore on a first end and another bore on a second end disposed opposite of the first end in the direction of the member axis. Each transmission member 152 is rotatably connected to an activation element 14a, 14b on a first end. This connection is respectively established by a bolt 1521 which is passed through the bore on the first end of each transmission member 152 and through associated bores in an activation element 14a, 14b. For example, the bolt 1521 may be mounted in press fit in the bores in the activation element 14a, 14b and in sliding fit in the bore on the first end of the transmission member 152. In this way, the transmission members 152 are rotatably supported relative to the activation element 14a, 14b and the coupling element 13a, 13b in a plane parallel to the central axis MA. The second ends of the transmission members 152 are rotatably connected to each other by a bolt 1522 through the bores disposed there. The bolt 1522 extends through the two bores in the second ends of the transmission members 152 and further protrudes into the sliding rail 1511 in the sliding element 151. Between at least one bore in a second end of a transmission member 152 and the bolt 1522, a sliding fit is established which renders a relative rotation of the components with respect to each other possible. At the same time, a sliding fit also exists between the outer circumference of the bolt 1522 and the surfaces of the sliding rail 1511 facing inwards so that the bolt 1522 is shiftable along the sliding rail 1511 in a direction perpendicular to the central axis MA. The member axes of the transmission members 152 are disposed at an acute angle to each other in a plane parallel to the central axis MA and rotatable with respect to each other about an axis perpendicular to the central axis MA. The details of the construction of the compensation mechanism 15 may also be modified to obtain the same or a comparable effect. The activation elements 14a, 14b are respectively connected to a transmission member 152 rotatable in a plane parallel to the central axis MA. The ends of the transmission members 152 disposed opposite of this connection, in turn, are also rotatably connected to each other in a plane parallel to the central axis MA. In addition, the second ends of the transmission members 152 are slidably supported in a sliding element 151 in a direction perpendicular to the central axis MA. The sliding element 151, in turn, is disposed in the basic body 11 so that it is linearly movable in the direction of the central axis MA. The compensation mechanism 15 functions as follows: First, a component having an irregular cross section is placed between the four clamping elements 12. Then, the actuator A is operated which results in the sliding element 151 being moved away from the clamping elements 12 in the direction of the central axis MA. This linear movement of the sliding element 151 is transmitted to the coupling elements 13a, 13b which also move away from the clamping elements 12 in the direction of the central axis MA in this way via the transmission members 152 and the activation elements 14a, 14b. Due to the kinematic coupling of the coupling elements 13a, 13b to the clamping elements 12, the movement of the coupling elements 13a, 13b is translated into a radial movement of the clamping elements 12 towards central axis MA. Due to the irregular cross section, one pair of opposing clamping elements 12 abuts on the object while there is still a distance between the clamping elements 12 of the other pair and the object. The coupling element 13a, 13b which is connected to the clamping elements 12 which already abut on the object will now remain in its position relative to the central axis MA. Due to the further movement of the sliding element 151 by the operation of the compensation mechanism 15, the other coupling element 13a, 13b is then moved further away from the clamping elements 12 so that the second pair of clamping elements moves further towards the object. From the point in time from which the first coupling element 13a, 13b is not moved further in the direction of the central axis MA, the transmission members 152 rotate around their connection points to the activation elements 14a, 14b and around their connection point to each other. At the same time, the bolt 1522 which connects the second ends of the transmission members 152 to each other is shifted within the sliding rail 1511. As soon as the second pair of clamping elements 12 also abuts on the object, the rotational movement of the transmission members 152 ends. A further movement of the sliding element 151 in the direction of the central axis MA is then again transmitted to both coupling elements 13a, 13b and therefore to all four clamping elements 12 via the compensation mechanism 15. With a slight further movement of the sliding element 151 in the direction of the central axis MA, the object is finally non-positively clamped by the interaction of the components kinematically coupled to each other. On principle, it is sufficient that altogether two activation elements 14a, 14b and altogether two transmission members 152 are provided to realise a compensation mechanism 15 according to the introduced operating principle. However, the illustrated second embodiment comprises altogether four activation elements 14a, 14b and four transmission members 152. Details relating thereto are described in connection with FIG. 6.
[0085] FIG. 6 shows a perspective view of a subsection of the components of the second embodiment of FIGS. 4 and 5 disposed within the basic body 11. In FIG. 6, the compensation mechanism 15 is illustrated in a perspective slightly changed as compared to the illustration in FIG. 5. In FIG. 6, it can be seen that the coupling element 13a is connected to two activation elements 14a. The activation element 14a illustrated on the right is connected to an activation element 14b of the other coupling element 13b via two transmission members 152. The other coupling element 13b is also connected to two activation elements 14b the rear one of which is concealed in the illustration. The left activation element 14a is also connected to the second activation element 14b of the other coupling element 13b via two transmission members 152. In the illustrated embodiment, the two coupling elements 13a, 13b are therefore connected to each other via altogether four activation elements 14a, 14b and four transmission members 152. The pairs of activation elements 14a, 14b and transmission members 152 are arranged on sides of the sliding element 151 disposed opposite of each other radial to the central axis MA. In this way, a symmetrical design of the compensation mechanism 15 is obtained which ensures a particularly good force transmission. Moreover, the risk of the compensation mechanism 15 getting jammed is considerably reduced by this symmetric design. It is also possible to provide additional pairs of activation elements 14a, 14b and transmission members 152 which, preferably, are regularly disposed in the circumferential direction around the central axis MA. When an object having an irregular cross section is clamped between the four clamping elements 14 and the compensation mechanism 15 compensates this irregular shape of the object during clamping as previously described the two bolts 1522 which project into the sliding rail 1511 move in opposite directions in the sliding rail 1511. For preventing a rotation of the sliding element 151 with respect to the coupling elements 13a, 13b while clamping or unclamping an object in the clamping device 1 a guiding spike F may be provided which is not illustrated in the illustrations in FIGS. 5 and 6 for the sake of clarity. Such a guiding spike F is illustrated in FIG. 7.
[0086] FIG. 7 shows a perspective view of the second embodiment illustrated in FIGS. 4, 5, and 6 including a guiding spike F. The embodiment illustrated in FIG. 7 corresponds to the embodiment presented in connection with FIGS. 5 and 6 but, in addition, comprises a guiding spike F which is guided by two internal guides 1331 in the central portions 133 of the coupling elements 13a, 13b. With regard to the components of the clamping device 1 not described in connection with FIG. 7, the description relating to FIGS. 5 and 6 is made reference to. For the sake of clarity, some components of the compensation mechanism 15, for example, the transmission members 152 are not illustrated in FIG. 7. The embodiments of FIG. 7 or FIGS. 5 and 6 can be freely combined with each other. In FIG. 7, a guiding spike F is provided which is fixedly connected to the sliding element 151 and extends upwards in the direction of the clamping elements 12 along the central axis MA. In a sectional plane perpendicular to the central axis MA, the guiding spike F has an irregular shape. The guiding spike F has the shape of a sword the width of which is considerably larger than its thickness. The internal guides 1331 have a shape complementary or negative to the cross section of the sword. The guiding spike F extends through both internal guides 1331 and is supported in these in sliding fit. In this way, the two coupling elements 13a, 13b can be linearly shifted relative to the guiding spike F in the direction of the central axis MA. With this support, the two coupling elements 13a, 13b can be moved independently. However, owing to the shape of the guiding spike F having an irregular cross section and the internal guides 1331, a rotational movement of each coupling element 13a, 13b about the central axis MA is prevented. In this way, it is ensured that the coupling elements 13a, 13b cannot rotate relative to the sliding element 151 connected to the guiding spike F. In this way, an undisturbed operation of the entire compensation mechanism 15 is ensured. Alternatively, also a plurality of guiding spikes F may be provided which may then also have a regular cross section such as, for example, a circular cross section. In case of a plurality of guiding spikes F, accordingly, also a plurality of internal guides having a shape complementary to the guiding spikes is integrated in the central portions 133.
LIST OF REFERENCE NUMERALS
[0087] 1 Clamping device [0088] 11 Basic body [0089] 111 Interface [0090] 113 Receiving space [0091] 112 Guide [0092] 1121 Insertion element [0093] 12 Clamping element [0094] 121 Coupling surface [0095] 122 Guide recess [0096] 13a, 13b Coupling element [0097] 131 Transmission element [0098] 132 Supports [0099] 1321 Sliding surface [0100] 133 Central portion [0101] 1331 Internal guide [0102] 14a, 14b Activation element [0103] 15 Compensation mechanism [0104] 151 Sliding element [0105] 1511 Sliding rail [0106] 152 Transmission member [0107] 1521 Bolt [0108] 1522 Bolt [0109] A Actuator [0110] F Guiding spike [0111] MA Central axis
