Internal clamping means

Abstract

The invention relates to a clamping means (12, 12') of the internal clamping means type for securing workpieces. The clamping means (12, 12') has a housing (20) which extends in an axial direction (2) and which has a clamping cone (22) that extends in the axial direction. The clamping means (12, 12') also has a segmented clamping bushing (50) with a plurality of clamping segments (60) which are movable in a radial direction (4) with respect to one another and which have, on their outer side, a clamping face (62) for contact with the workpiece. The clamping segments (60) have, on their inner side, inclined sliding faces (64) for contact with the outer face of the clamping cone, such that the clamping segments (60) are radially movable relative to one another by being jointly moved axially with respect to the clamping cone (22). The outer face (24) of the clamping cone (22) has a cross-sectionally non-round shape and the sliding faces (64) of the clamping segments (60) have a shape corresponding to this non-round shape, wherein the clamping means (12) also has a coupling element (40) that is movable relative to the housing (20) or has a removable coupling element (40') which is able to be attached from the outside and by means of which a proximal end of the segmented clamping bushing (50) is retained on the clamping cone (22).

Description

[0001] Internal clamping devices

[0002] FIELD OF APPLICATION AND STATE OF THE ART

[0003] The invention relates to a clamping device in the form of an internal clamping device for securing workpieces, in particular for the purpose of rotary machining of these workpieces.

[0004] By means of a generic internal clamping device, workpieces are clamped in particular which have a central recess, so that these workpieces can be clamped on their inner circumference by the clamping surfaces of outwardly acting clamping segments.

[0005] A generic clamping device has a housing extending in an axial direction with a clamping cone extending in the axial direction. Such clamping cones typically have a circular cross-section. A segmented clamping bushing is slid onto the clamping cone, the outer surface of which forms a clamping surface for engagement with the inner circumference of the workpiece. The segmented clamping bushing of a generic clamping device, as well as of a clamping device according to the invention, has a number of clamping segments that are movably connected to one another, in particular by elastically deformable connecting sections between the clamping segments.

[0006] The workpiece is pushed onto the outside of the segmented clamping bush. The segmented clamping bush as a whole is then moved axially relative to the clamping cone, expanding due to the conical shape of the clamping cone and pressing the clamping surface of the segmented clamping bush against the inner circumference of the workpiece. This clamps the workpiece firmly.

[0007] A generic clamping device is usually attached to a rotary spindle and has a spindle-side housing, the distal end of which is formed by the clamping cone.

[0008] TASK AND SOLUTION

[0009] The object of the invention is to provide an improved clamping device of the type described above.

[0010] To achieve this object, the invention proposes a clamping device which, in accordance with generic clamping devices, has a housing extending in an axial direction and a clamping cone of the type mentioned above that defines the axial direction and extends in the axial direction. The clamping cone has a circumferential outer surface that tapers towards a distal end. For interaction with this, the clamping device has a segmented clamping sleeve with a plurality of clamping segments that are movable relative to one another in the radial direction and that have a clamping surface on their outer side for engagement with the workpiece.

[0011] To interact with the clamping cone, the clamping segments have inclined sliding surfaces on their inside to engage with the outer surface of the clamping cone, so that the clamping segments can be radially displaced relative to one another by common axial displacement relative to the clamping cone.

[0012] According to the invention, it is proposed that the outer surface of the clamping cone has a non-circular cross-section and that the sliding surfaces of the clamping segments are shaped to correspond to this non-circular shape. In particular, the clamping cone preferably has a polygonal outer shape. A hexagonal shape is preferred. The corresponding shape of the clamping segments means that they have a shape on the inside with which they can rest flat against the clamping cone. In the case of a polygonal and in particular hexagonal cross-sectional shape of the clamping cone, the clamping segments are each provided on the inside with two sliding surfaces angled to one another. In the case of a clamping cone with a hexagonal cross-section, this means that in the case of three clamping segments, their sliding surfaces are angled to one another by 120°.

[0013] The non-circular shape represents an advantage with regard to the torque transmission from the clamping cone to the segment clamping bush. Twisting of the segment clamping bush relative to the clamping cone cannot occur.

[0014] The outer surface of the clamping cone and the inner sides of the clamping segments can in particular be formed by at least partially flat surface sections, so that the corresponding surface sections lie flat against one another regardless of the axial movement of the segment clamping bush relative to the clamping cone.

[0015] The non-circular shape of the clamping cone means that the prior art method of coupling the segmented clamping bush to the housing via a bayonet is no longer available. Once the segmented clamping bush is pushed onto the clamping cone, it is no longer possible to rotate it relative to the clamping cone, which is stationary relative to the housing. In order to still be able to secure and, in particular, clamp the segmented clamping bush, a coupling element that is movable relative to the housing or a coupling element that can be removed and attached as a whole is provided, by means of which a proximal end of the segmented clamping bush is held on the clamping cone. The proximal end of the clamping cone is considered to be the end pointing towards the housing or the spindle. The distal end of the clamping cone is the opposite free end.

[0016] The clamping device is preferably designed for attachment to a rotary spindle and has screw holes in the housing for attachment to the rotary spindle, through which fastening screws can be screwed into one end face of the rotary spindle. The clamping cone is provided as part of a rigid and preferably one-piece housing, which includes both the screw holes and the clamping cone.

[0017] In addition to securing the segment clamping bush to the housing against axial removal, the coupling element preferably also serves the function of exerting an axial force acting in the proximal direction on the segment clamping bush. This force is coupled into the segment clamping bush at the proximal end and by means of which the segment clamping bush can be further pulled onto the clamping cone, thereby causing the circumferential expansion of the segment clamping bush and thus the radial outward displacement of the clamping segments, thereby creating a clamped state of the workpiece. By attaching the coupling element to the proximal end of the segment clamping bush, the coupling element is able to pull the segment clamping bush onto the cone using tensile stress, thereby expanding it.

[0018] In the variant of the invention with a coupling element that can be removed as a whole, it is provided that after sliding the segment clamping sleeve onto the clamping cone, the coupling element is attached to the proximal end.

[0019] The coupling element can in particular be designed as a multi-part or multi-link coupling element which is completely disassembled for the purpose of laterally placing it on the segment clamping bush, for example into two completely separable links which can be connected to one another.

[0020] The coupling element is preferably designed as an inherently deformable coupling element comprising at least two rigid sub-elements that are movably attached to one another, in particular by means of at least one elastically deformable connecting element, wherein the two sub-elements together form a coupling ring interrupted at one point. Such a coupling ring can be deformed and, in particular, unfolded by means of the connecting element acting as a joint, so that the unfolded coupling ring can be placed on the outside of the proximal end of the segment clamping sleeve from the side. There, it can then be brought into the configuration that circumferentially surrounds the segment clamping sleeve by joining them together.

[0021] When attached, the removable coupling element couples the segmented clamping bushing to an axially movable control element, which extends outward through openings in the housing of the clamping device. The removable coupling element has a cross-sectional shape by means of which the segmented clamping bushing can be connected to the control element in such a way that a tensile force can be transmitted. In particular, the removable coupling element can have a C-shaped profile. The tensile force transmitted via the coupling element allows the segmented clamping bushing to be pulled further onto the clamping cone, thereby increasing the circumference of the clamping surface, thus firmly clamping the workpiece.

[0022] Preferably, a protective sleeve is additionally provided, which surrounds the removable coupling element in the assembled state and thus prevents the coupling element from accidentally separating from the control element or the segmented clamping sleeve. The protective sleeve is pushed axially onto the coupling element after it has been attached and is preferably secured to a front side of the clamping device housing.

[0023] Another variant of the invention is considered advantageous in comparison: In this second variant of the invention, the coupling element is designed as an inherently rigid coupling element. In this case, the coupling element has a rigid and approximately annular structure that can be pushed onto the clamping cone from the distal end during assembly of the coupling element before attaching the segmented clamping bushing, and by means of which the segmented clamping bushing is subsequently secured to the clamping cone. An annular structure or a coupling ring is understood to mean that the inherently rigid body has a central opening by means of which it can be pushed onto the clamping cone.

[0024] In particular, the coupling element or coupling ring can be mounted so that it can rotate relative to the housing of the clamping device. Thus, when mounted, the coupling element can rotate relative to the clamping cone. The rotatability of the coupling element is intended to secure the segmented clamping bush. The rotational movement rotates the coupling element relative to the segmented clamping bush about the central axis of the clamping cone.

[0025] This can be used to axially secure the segmented clamping bush, with corresponding locking contours being provided on the coupling element and the segmented clamping bush. In particular, these locking contours can act in the manner of a bayonet. For this purpose, the locking contours are coordinated with one another by means of their interacting shapes such that in a first rotational position, the release position, the locking contour of the segmented clamping bush can be inserted into the coupling element, and that in a second rotational position, the locking position, the locking contours of the segmented clamping bush and the coupling element prevent the segmented clamping bush from being pulled off the clamping cone.

[0026] This makes it possible to slide the segmented clamping bushing onto the clamping cone and insert it into the opening of the coupling element when the coupling element is in the release position for coupling the segmented clamping bushing. The coupling element is then rotated, for example, by 15°, thus creating the locking position in which the segmented clamping bushing cannot be removed from the clamping cone.

[0027] Preferably, the release position and the locking position are spaced apart by a maximum of 20°, preferably a maximum of 15°. This allows switching between the release position and the locking position with a comparatively small rotational movement of the coupling element. This is particularly helpful in order to avoid excessively weakening the connection of the clamping cone to the surrounding housing through openings that serve to transmit force between a control element in the housing and the coupling element.

[0028] The securing contours on the clamping segment bushing and on the coupling element are preferably designed such that the securing contour of the segment clamping bushing is in the form of an outwardly facing collar. This collar is preferably formed by collar sections molded integrally with the clamping segments or at least some of the clamping segments. Correspondingly, the securing contour on the coupling element is in the form of an inwardly facing collar. In the securing position, the segment clamping bushing collides with the collar of the coupling element due to its collar when it is pulled towards the distal end of the clamping cone. By moving the coupling element in the proximal direction, a force is introduced into the segment clamping bushing via the securing contours, which pulls the segment clamping bushing further onto the clamping cone while simultaneously expanding it.

[0029] The collars on the coupling element and the segmented clamping bushing are typically not circumferentially continuous collars, but can be formed by a plurality of individual collar segments. In the case of a segmented clamping bushing, a collar segment is preferably provided on at least each clamping segment. The collar on the coupling element can be formed as a circumferential collar. However, a design with a plurality of collar segments is also possible here.

[0030] Particularly preferably, the securing contour on the coupling element and / or on the segmented clamping bushing is circumferentially non-uniform, so that in the release position, the segmented clamping bushing can only be pushed through the coupling element in a defined rotational orientation. Provided that the coupling element always remains in the same position relative to the housing of the clamping device in its securing position with respect to the rotational position, this ensures that the same surface sections on the inside of the segmented clamping bushing always rest against the same surface sections of the clamping cone. This promotes the manufacturing accuracy achievable with the clamping device.

[0031] In particular, this can be achieved by providing the securing contour of the segmented clamping bushing on the clamping segments, with at least one clamping segment having a securing contour that differs from the securing contour of at least one other clamping segment. Particularly preferably, the segmented clamping bushing has at least three clamping segments, of which at least two clamping segments are structurally identical, while at least, and preferably exactly one clamping segment, has a different shape in the area of ​​the securing contour.

[0032] In order to be able to further pull the segment clamping bush onto the clamping cone by means of the coupling element and thereby to clamp the workpiece, the coupling element is provided to establish a direct or indirect connection with a control element located in the housing and which is at least axially movable.

[0033] For this purpose, it is preferably provided that the housing has at least one opening through which the coupling element itself or a force transmission member that can be coupled to the coupling element in the axial direction projects into the housing, in order to be connected to the control element there, so that an axial movement of the control element relative to the housing leads to an axial movement of the coupling element relative to the housing. Preferably, one or more integrally formed elongated force transmission members are provided on the coupling element, which extend through the openings into the housing and up to the control element.

[0034] In particular, this can serve the purpose of connecting the coupling element to the control element in an axially fixed manner, so that the segment clamping bush coupled by means of the coupling element can be moved axially relative to the clamping cone via an axial displacement of the control element and thereby a workpiece can be clamped to and released from the segment clamping bush.

[0035] Alternatively or additionally, it can be provided that the coupling element is connected to the control element in a rotational manner with respect to the central axis, so that by means of a rotational displacement of the control element, the coupling element can also be rotated relative to the clamping cone and the segment clamping bush and can thus be moved into the locking position and the release position depending on the direction of rotation.

[0036] To couple the control element within the housing to the coupling element on the outside, the housing preferably has a plurality of openings through which the coupling element is connected to the control element arranged in the housing of the clamping device. This plurality of openings is preferably evenly distributed around the circumference. In particular, the number of openings is preferably an integer multiple of the number of sides of the polygonal clamping cone, or the number of sides of the polygonal clamping cone is an integer multiple of the number of openings. In particular, the number of openings can also correspond to the number of sides of the clamping cone. In particular, the number of openings is at least three and particularly preferably exactly six.

[0037] A force or torque can be evenly applied to the coupling element by the control element through the plurality of openings. Webs remain between the openings to firmly connect the clamping cone, preferably in one piece, to a housing section surrounding the openings, thereby ensuring the rigidity of the clamping cone.

[0038] The openings are preferably designed as elongated holes, particularly in the form of circular segment-shaped elongated holes. They therefore extend further in the circumferential direction than in the radial direction. Designing the openings as elongated holes, with appropriately designed connecting segments between the coupling element and the control element, allows the coupling element to remain permanently coupled to the control element while being rotated between the release position and the locking position for the purpose of coupling to the segmented clamping sleeve.

[0039] As already explained, a design is possible in which the rotation of the coupling element is effected by a drive element located in the housing, such as in particular a rotatable control element.

[0040] A particularly preferred design, however, provides that the rotation of the coupling element about the central axis occurs on the outer side. For this purpose, an outer element is preferably provided which is positively connected to the coupling element with respect to rotation about the central axis and is accessible from the outside. In particular, the outer element can be designed as an outer ring surrounding the coupling element, which is designed in particular as a coupling ring. To produce the rotationally acting positive connection, a torque pin or a torque recess is preferably provided on the outer element and a torque recess or a torque pin of the coupling element. The torque pin on one of the components engages in the torque recess on the other component and effects a rotational positive connection.Preferably, however, the torque pin and the torque recess are coordinated in such a way that axial relative movement between the outer element and the coupling element remains possible. If the coupling element is displaced axially relative to the housing and the clamping cone for the purpose of clamping and unclamping the workpiece, the outer element can still remain stationary.

[0041] The outer element can be provided to effect the release position and the securing position of the coupling element by means of a rotational movement. In particular, however, the outer element serves to rotationally secure the coupling element in its securing position. In particular, the outer element is preferably designed for attachment to the housing in order to thereby ensure the rotational position of the coupling element in the securing position. For the purpose of securing the outer element to the housing, it can be provided, in particular, that the outer element has at least one bore adapted to the housing, through which the outer element can be screwed tightly to the housing. The clamping means according to the invention has a housing whose distal end is formed by the clamping cone.Within this housing, a pulling element is preferably provided in order to introduce the force required for clamping into the segment clamping bush via the control element and the doubling element.

[0042] The clamping device preferably has a protective shield to prevent dirt and chips from entering the area of ​​the locking contour. This is useful to prevent dirt, or especially chips, from getting between the contact surfaces of the locking contour and thus causing asymmetric force transmission from the coupling element to the segmented clamping bush.

[0043] The segment clamping bush preferably has a protective shield that protects the locking contours of the coupling element and / or the segment clamping bush when the segment clamping bush is assembled. The protective shield is preferably designed as an annular protective shield that surrounds the clamping segments and is offset from the locking contour of the segment clamping bush toward the distal end.

[0044] The protective shield is preferably made of a rubber-like, elastic material. It is particularly preferred that the protective shield be designed as a single piece with elastic connecting elements provided between the clamping segments. A segment clamping bush designed in this way thus has a continuous elastic partial body that simultaneously forms the protective shield and the connecting elements between the clamping segments.

[0045] The coupling element is preferably provided with a frontal and in particular flat contact surface against which the protective cover of the segment clamping bush rests all around after the segment clamping bush has been attached.

[0046] BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Further advantages and aspects of the invention emerge from the claims and from the following description of preferred embodiments of the invention, which are explained below with reference to the figures.

[0048] Figs. 1 and 2 show an overall view of a clamping device according to the invention, with Fig. 2 showing the clamping device in section. Fig. 3 shows the clamping device in disassembled form.

[0049] Fig. 4 and 5 show a coupling element and a segment clamping bush of the clamping device in individual representation.

[0050] Fig. 6 and 7 show a clamping device according to the invention in a different design.

[0051] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] Fig. 1 and 2 show a clamping device 12 according to the invention in an overall view or, in the case of Fig. 2, in a sectional view.

[0053] A clamping device 12 is particularly intended to be attached to the distal end of a rotary spindle 100, the distal end of which is shown in Fig. 1. This allows a workpiece clamped by means of the clamping device 12 to be set in rotational motion, for example, to be machined.

[0054] The clamping device 12 has a housing 20, which is attached to the rotary spindle 100 for this purpose. Screw holes 28 are provided in the housing 20 for fastening the housing 20 to the rotary spindle 100. At the distal end of the housing 20, which faces to the right in the figures, there is a clamping cone 22 that defines the central axis 2 of the clamping device, wherein this central axis 2 coincides with the rotational axis 2 of the rotary spindle 100. A segmented clamping bushing 50 is mounted on the clamping cone 22, which in turn has three metallic clamping segments 60. These clamping segments 60 are connected to one another via connecting elements 58 made of rubber or the like.

[0055] The clamping segments 60 each have a clamping surface 62 on their outer side. Due to the conical shape of the clamping cone 22 and corresponding sliding surfaces 64 on the inner side of the clamping segments 60, a radial expansion of the segment clamping bush 50, indicated by the arrows 4, can be achieved by further pulling the segment clamping bush onto the cone in the clamping direction 2A.

[0056] For the purpose of mounting the segmented clamping sleeve 50 onto the clamping cone 22 and thus for the purpose of applying force to clamp workpieces, a coupling element 40 is provided. This coupling element 40 has an annular structure and comprises connecting elements 48 that extend through openings 26 in the housing 20 into an interior of the housing 20 and are connected there to a control element 80. If the control element 80 is displaced within the housing 20 in the clamping direction 2A or the unclamping direction 2B, the annular coupling element 40 is also displaced.

[0057] Cooperating sections 43, 53 are provided on the segment clamping bush 50 and the coupling element 40, which will be explained below and which ensure that an axial movement of the coupling element 40 in the clamping direction 2A also leads to an axial movement of the segment clamping bush 50 and can therefore be pulled further onto the clamping cone 22.

[0058] The coupling element 40, together with the control element 80, is rotatable to a limited extent about the central axis 2. An outer element 30 is provided on the outside of the coupling element, which is connected to the coupling element 40 via a torque coupling in the form of a torque pin 32 and a torque recess 44, the significance of which will be explained below.

[0059] Referring to Fig. 3, the aforementioned openings 26 are provided in one end face of the housing 20, surrounding the clamping cone 22. In the present embodiment, there are a total of four openings. Depending on the required rigidity, a different number of openings may also be appropriate.

[0060] As can also be seen from Fig. 3, the outer shape of the clamping cone 22 is not rotationally symmetrical, but polygonal. The outer surface 24 is thus formed primarily by a number of flat or largely flat individual surfaces 24A, in this case by six individual surfaces 24A.

[0061] As can be seen from Fig. 5, the inside of the segmented clamping bushing 50 is constructed correspondingly. The sliding surfaces 64 on the inside of the three clamping segments 60 are arranged such that two sliding surfaces 64 are provided on each of the clamping segments 60, which are at an angle of 120° to each other and are therefore aligned with adjacent individual surfaces 24A.

[0062] The polygonal shape of the clamping cone 22 and the entirety of the sliding surfaces 64 means that rotation of the segmented clamping bush 50 pushed onto the clamping cone 22 is impossible. However, it is advantageous that the sliding surfaces 64 and the individual surfaces 24A of the clamping cone 22 are permanently in surface contact during operation. The described rotatability of the coupling element 40 about the central axis 2 serves the purpose of ensuring that the segmented clamping bush 50 is attached to the coupling element 40 and thus indirectly to the control element 80 and to a pulling element of the rotary spindle 100, despite the polygonal shape of the clamping cone 22. Since the segmented clamping bush 50 can no longer be rotated after being pushed onto the clamping cone 22, the coupling is established by the aforementioned rotatability of the coupling element 40.

[0063] Securing contours 53 are provided for coupling and axial force transmission between the coupling element 40 and the segmented clamping bush 50. The securing contour on the coupling element side is shown in Fig. 4. As can be seen here, this securing contour 53 forms an inwardly facing collar with a plurality of radially exposed projections, in this case in a kind of wave shape.

[0064] As can be seen from Fig. 5, a corresponding wave shape is also provided on the segmented clamping bushing 50, namely by providing three outward-facing securing contour sections 63A, 63B, 63C on the clamping segments 60. As can also be seen from Fig. 5, the shape is not identical on all clamping segments 60. The clamping segment 60 with the securing contour section 63A has a continuous, radially exposed extension that is wider than the other extensions.

[0065] To assemble the segmented clamping sleeve 50, the coupling element 40 is first moved into an axial end position in the unclamping direction 2B by means of the control element 80. The coupling element 40 is then rotated into a release position. This can be achieved, in particular, by means of the outer element 30, which is not fixed to the housing 20 at this time. This outer element is rotated about its central axis and, due to its coupling with the coupling element 40 via the torque pin 32 and the torque recess 44, also rotates the coupling element 40.

[0066] In the release position thus achieved, the segment clamping bush 50 can be pushed on and the securing contours 53, 43 allow them to be guided past one another by appropriate alignment of the respective extensions.

[0067] As soon as the segmented clamping bushing has been pushed sufficiently far onto the clamping cone, the coupling element 40 is rotated by approximately 15°, again preferably by means of the outer element 30, so that the projections on the securing contours 43, 53 overlap, thus preventing direct axial separation of the segmented clamping bushing 50 from the clamping cone 22. This condition is secured by screwing the outer element 30 tightly to the housing 20.

[0068] The clamping device is now ready for operation.

[0069] By means of an axial displacement of the control element 80 and thereby indirectly an axial displacement of the coupling element 40 and the segment clamping bush 50, the latter can be further drawn onto the clamping cone 22, thereby being radially expanded and, as a result, creating a clamping state on the workpiece lying on the outside of the segment clamping bush 50.

[0070] If the workpiece needs to be changed, the control element 80 is moved in the unclamping direction 2B via the tension element 90, with the coupling element 40 also moving along with it. The coupling element 40 therefore allows the segmented clamping bush 50 to be displaced relative to the clamping cone 22 in the unclamping direction 2B and thus to contract radially under the pressure of the connecting elements 58, which were previously tangentially clamped. This releases the stress on the workpiece, and the workpiece can be removed and replaced with another workpiece to be machined.

[0071] During this tool change, there is no risk of the segment clamping bush 50 becoming detached from the coupling element 40, because the required rotatability of the coupling element 40 relative to the clamping cone 22 and the segment clamping bush is prevented by the outer element 30.

[0072] If the segmented clamping bush 50 itself is to be replaced, the coupling element 40 is moved in the unclamping direction 2B, as is the case with a workpiece change. The outer element 30 is then released from its fastening so that it can be rotated relative to the housing 20. By rotating the outer element 30 and thus also the coupling element 40, the latter is rotated back into the release position, in which the segmented clamping bush 50 can then be removed without collision of the securing contours 53, 43.

[0073] 6 and 7 show an alternative design of a clamping device according to the invention. Similar to the clamping device 12 described above, the clamping device 12' also features a housing 20 with a clamping cone 22 that tapers toward a distal end and has a polygonal outer shape with six individual surfaces 24A angled toward one another. The clamping cone 22 serves to receive the segment clamping bush 50, which has inclined sliding surfaces 64 on the inside in accordance with Figure 5. In the design of Figures 6 and 7, however, the coupling of the segment clamping bush 50 to the control element for the purpose of axial displacement is different from the design of Figures 1 to 5. The control element 80 has eight tension arms 84 that extend through openings 26' in the housing 20 and are provided with outwardly facing lugs 85 on the outside of the housing 20.

[0074] The segment clamping bush 50 has three clamping segments 60, at the end of which pointing towards the housing 20, outwardly pointing coupling flanges 55 are provided.

[0075] In order to attach the segmented clamping sleeve 50 to the tension arms 84 of the control element 80 and to couple a tensile force into the segmented clamping sleeve 50 via the control element 80, thereby enabling the clamping of a workpiece, a multi-element coupling element 40' is provided. This coupling element 40' consists of two metallic half-shells 41', which are connected by means of an elastic connecting element 42', so that they can be folded open under elastic deformation of the connecting element 42'.

[0076] This allows, after pushing the segment clamping bush 50 onto the clamping cone 22, the unfolded coupling element 40' to be guided from the side over the tension arms 84 and their lugs 85 as well as over the coupling flanges 55 and then to be closed again into the initial shape of Fig. 7.

[0077] The state shown in Fig. 6 is established, in which the coupling element 40' creates a positive-locking coupling due to its C-profile shape. By displacing the control element 80 to the left in relation to Fig. 6, the coupling element 40' and the segmented clamping bushing 50 are also displaced to the left, and the segmented clamping bushing 50 is expanded for the purpose of clamping a workpiece.

[0078] To prevent the coupling element 40' from opening accidentally and thus losing the positive coupling between the control element 80 and the segmented clamping bushing 50, a protective sleeve 30' is provided. After the coupling element 40' has been attached, this is pushed from the distal end over the segmented clamping bushing 50 and the coupling element 40' and secured to the housing 20 by means of a screw.

[0079] This second design is technically simpler and can therefore be economically advantageous. However, with such a design, the clamping cone 22 is comparatively long, so that the rigidity tends to be lower than with the design shown in Figs. 1 to 5. The design shown in Figs. 1 to 5 is therefore considered advantageous overall.

Claims

Patent claims 1. Clamping device (12, 12') in the form of an internal clamping device for securing workpieces, in particular for the purpose of rotary machining these workpieces, with the following features: a. the clamping device (12, 12') has a housing (20) extending in the axial direction (2), and b. the housing (20) has an axially extending clamping cone (22) which has a circumferential outer surface (24) which tapers towards a distal end, and c. the clamping device (12, 12') has a segment clamping bush (50) with a plurality of clamping segments (60) which are movable relative to one another in the radial direction (4), and d. the clamping segments (60) have a clamping surface (62) on their outer side for contact with the workpiece, and e.the clamping segments (60) have inclined sliding surfaces (64) on their inner side for contact with the outer surface of the clamping cone, so that the clamping segments (60) can be radially displaced relative to one another by common axial displacement relative to the clamping cone (22), with the following additional features: f. the outer surface (24) of the clamping cone (22) has a non-circular shape in cross-section and the sliding surfaces (64) of the clamping segments (60) are shaped to correspond to this non-circular shape, and g. the clamping means (12, 12') has a coupling element (40) that is movable relative to the housing (20) or a removable coupling element (40') that can be attached from the outside, wherein a proximal end of the segment clamping bushing (50) is held on the clamping cone (22) by means of the coupling element (40, 40').

2. Clamping means (12, 12') according to claim 1 with the following additional feature: a. the cross section of the clamping cone (22) has a polygonal outer shape, in particular a hexagonal outer shape, preferably with the following additional feature: b. the clamping segments (60) of the segment clamping bush (50) each have two sliding surfaces (64) angled to one another, in particular two sliding surfaces (64) at an angle of 120° to one another.

3. Clamping means (12) according to claim 1 or 2 with the following additional feature: a. the coupling element (40) is designed as an inherently rigid coupling element (40).

4. Clamping means (12) according to one of the preceding claims with the following additional feature: a. the coupling element (40) is designed as a coupling element (40) that is rotatable about a central axis of the clamping cone (22).

5. Clamping means (12) according to claim 4 with the following additional features: a. the coupling element (40) and the segment clamping bush (50) have mutually corresponding securing contours (43, 53), and b. the securing contours (43, 53) are coordinated with one another in such a way that in a first rotational position, the release position, the securing contour (53) of the segment clamping bush (50) can be pushed into the coupling element (40) and that in a second rotational position, the securing position, the securing contours (43, 53) of the segment clamping bush (50) and the coupling element (40) prevent the segment clamping bush (50) from being pulled off the clamping cone (22), preferably with the additional feature: c. the release position and the securing position are spaced from one another by a maximum of 20°, preferably by a maximum of 15°.

6. Clamping means (12) according to claim 5 with the following additional features: a. the securing contour (53) of the segment clamping bush (50) is designed in the form of an outwardly facing collar on at least some of the clamping segments (60), and b. the securing contour (43) of the coupling element (40) is designed in the form of an inwardly facing collar.

7. Clamping device according to claim 5 or 6 with the following additional feature: a. the securing contour (43, 53) on the coupling element (40) and / or on the segment clamping bush (50) is circumferentially non-uniform, so that in the release position the segment clamping bush (50) can only be pushed through the coupling element (40) in a defined rotational orientation.

8. Clamping device according to claim 7 with the following additional feature: a. the securing contour (53) of the segment clamping bush (50) is provided on the clamping segments (60), wherein at least one clamping segment has a securing contour section (63A) which deviates from securing contour sections (63B, 63C) of at least one other clamping segment (60).

9. Clamping means (12) according to one of claims 4 to 8 with the following additional feature: a. for rotating and / or securing the coupling element (40) against rotation, an outer element (30) is provided which is positively connected to the latter with respect to rotation, preferably with at least one of the following additional features: b. the outer element (30) is designed in the manner of an outer ring (30) surrounding the coupling element (40), and / or c. the outer element (30) is designed for attachment to the housing (20) and in particular has at least one bore adapted to the housing.

10. Clamping means (12) according to claim 9 with the following additional feature: a. the outer element (30) and the coupling element (40) are displaceable relative to one another in an axial direction, preferably with the following additional feature: b. to produce the positive connection, a moment pin (32) or a moment recess is provided on the outer element (30), which engages with a moment recess (44) or a moment pin of the coupling element (40).

11. Clamping device (12) according to one of the preceding claims with the following additional feature: a. the housing (20) has at least one opening (26) through which the coupling element (40) is connected to a control element (80) arranged in the housing (20) of the clamping device (12), so that a movement of the control element (80) relative to the housing (20) leads to a movement of the coupling element (40) relative to the housing (20), preferably with at least one of the following additional features: b. the coupling element (40) is axially fixedly connected to the control element (80), so that via an axial displacement of the control element (80) the segment clamping bush (50) coupled by means of the coupling element (40) can be moved axially relative to the clamping cone and as a result a workpiece can be clamped to and released from the segment clamping bush (50), and / or c.the coupling element (40) is connected to the control member (80) in a rotational manner with respect to the central axis, so that by means of a rotational displacement of the control member (80) the coupling element (40) can be rotated relative to the segment clamping bush (50) and can thus be brought into the securing position and the release position, and / or. d. the housing (20) has a plurality of openings (26) through which the coupling element (40) is connected to the control member (80) arranged in the housing (20) of the clamping means (12), wherein preferably at least three openings (26) and in particular preferably exactly six openings (26) are provided, wherein preferably the at least one opening (26) is designed in the form of an elongated hole, in particular in the form of an elongated hole in the shape of a segment of a circle.

12. Clamping device (12) according to one of the preceding claims with the following additional feature: a. the clamping device (12) has a pulling element (90) arranged within the housing (20) of the clamping device (12), by means of which the segment clamping bush (50) can be displaced in the proximal direction on the clamping cone (22) in order to thereby cause an expansion of the clamping surface (62) of the segment clamping bush (50).

13. Clamping means (12) according to one of the preceding claims 5 to 12 with the following additional feature: a. the segment clamping bush (50) has a protective cover (56) which, in the assembled state of the segment clamping bush (50), protects the securing contours (43, 53) of the coupling element (40) and / or the segment clamping bush (50), in particular with at least one of the following additional features: b. the protective cover (56) is made as an annular protective cover (56) and preferably from a rubber-like material, wherein the protective cover (56) is preferably designed in one piece with connecting elements (58) provided between the clamping segments (60), and / or c. the coupling element (40) has an end-side contact surface (46) and, in the assembled state of the segment clamping bush (50), the protective cover (56) rests circumferentially on the contact surface (46).

14. Clamping means (12') according to claim 1 or 2 with the following additional feature: a. the coupling element (40') is designed as an inherently deformable coupling element (40'), in particular with the additional feature: b. the coupling element (40') has at least two rigid and preferably metallic sub-elements (41') which are movably attached to one another, in particular by means of an elastically deformable connecting element (42'), wherein the two sub-elements (41') together form a coupling ring (40) which is interrupted at one point, and / or c. the coupling element (40') is designed at least in sections with a C-shaped profile cross-section for the positive coupling of a control element (80) to the segment clamping bush (50).

15. Clamping device (12) according to one of the preceding claims with at least one of the following further features: a. the clamping device (12) is designed for attachment to a rotary spindle (100) and has screw holes (28) in the housing through which fastening screws can be screwed into an end face of the rotary spindle, and b. a rigid and preferably one-piece housing (20) is provided which comprises both the screw holes (28) and the clamping cone (22).

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