clamping device

Description

[0001] The invention relates to a clamping device for clamping a pallet on a pallet holder of the clamping device with a clamping mechanism which is designed to carry out a clamping movement of an axially movable clamping member running along a clamping axis and a rotational movement of a radially extending coupling region of the clamping mechanism running around the clamping axis, wherein the rotational movement serves for the axially fixed coupling engagement of the coupling region of the clamping mechanism with a coupling counter region of the pallet and the clamping movement serves to clamp the coupled pallet on the pallet holder.

[0002] Such clamping devices are known from the prior art, for example from EP 2 774 717 B1. The clamping device disclosed therein has a pull rod as a clamping element, which is connected at its lower end to a piston of a pressure-medium-operated piston-cylinder arrangement that is movable along the clamping axis. The piston is subjected to a spring force in the direction of the clamping movement by a spring arrangement, which generates the clamping force required to clamp the pallet. To release the clamping force, compressed air is supplied to a space beneath the piston. The pull rod has at least one projection at its upper end as a coupling region, which can enter into a positive connection with the pallet through a rotational movement of the pull rod.To do this, the drawbar is rotated around its clamping axis using a positive guide, such as an S-shaped guide, and simultaneously moved downwards by spring force. As soon as the coupling area of ​​the drawbar engages with the pallet, the remaining spring force of the spring assembly clamps the pallet onto the pallet holder.

[0003] Clamping systems that allow a pallet to be clamped reproducibly, i.e., with a maximum deviation of a few thousandths of a millimeter, are referred to as zero-point clamping systems. The requirements for zero-point clamping systems are diverse. They require high levels of accuracy, stability, and clamping force, while simultaneously being flexible in use, having a compact design, and being cost-effective to manufacture. Furthermore, they should be easy to operate. To achieve these objectives, existing clamping devices need to be improved.

[0004] The invention is based on the object of developing a clamping device of the type mentioned at the outset in such a way that a high clamping force can be achieved while at the same time having a simple structure of the clamping device.

[0005] According to the invention, this object is achieved in that the coupling region of the clamping mechanism is formed on a coupling member which is rotatably mounted on the clamping member and absorbs axial force.

[0006] A clamping device according to the invention enables the clamping of a so-called pallet onto a pallet holder of the clamping device. A pallet refers to a support on which a workpiece or tool to be clamped can be secured for a machining operation. The pallet holder serves as a counter-stop for clamping the pallet.

[0007] The clamping device has a clamping mechanism. The clamping mechanism has a clamping element and a coupling area. The coupling area of ​​the clamping mechanism can be coupled to a coupling counter area of ​​the pallet.

[0008] The tendon is axially movable along a tensioning axis. A tensioning movement of the tendon along the tensioning axis can generate a tensioning force between the pallet and the pallet holder to clamp the pallet coupled to the coupling area of ​​the clamping mechanism. The tendon can be axially movable between a clamped position, in which a tensioning force acts on the pallet when the pallet is coupled, and a relaxed position, in which no tensioning force acts on the pallet when the pallet is coupled. The tensioning axis can, for example, run parallel to the direction of gravity, but is not limited to this.

[0009] The coupling area of ​​the clamping mechanism extends radially to the clamping axis and is designed to perform a rotational movement around the clamping axis. The coupling area is therefore rotatable around the clamping axis. The rotational movement of the coupling area serves to ensure axially fixed coupling engagement of the coupling area of ​​the clamping mechanism with the mating coupling area of ​​the pallet.

[0010] In the clamping device according to the invention, the coupling region of the clamping mechanism is formed on a coupling member. The coupling member is rotatably mounted on the clamping member. The clamping mechanism thus has a two-part structure consisting of the clamping member and the separate coupling member on which the coupling region is formed. By rotating the coupling member around the clamping member in a coupling direction, the coupling region of the clamping mechanism and the counter-coupling region of the pallet can be brought into an axially fixed coupling engagement. The coupling engagement can be released by rotating the coupling member in a decoupling direction opposite to the coupling direction.

[0011] Furthermore, the coupling element is mounted on the tendon to absorb axial forces. A movement of the tendon along the tension axis thus causes a movement of the coupling element along the tension axis. The coupling element can be mounted on the tendon in an axially fixed manner. The coupling element can have a section for axially fixed coupling engagement with a mating section of the tendon. Alternatively, the coupling element can be mounted on the tendon with a clearance along the tension axis.

[0012] In order to clamp a pallet onto the pallet holder of the clamping device according to the invention, the coupling counter-region of the advanced pallet is first brought into axially fixed coupling engagement with the coupling region of the clamping mechanism by a rotational movement of the coupling member rotatably mounted on the clamping member in the coupling direction. Movement of the clamping member is not required for this purpose. The clamping member is then clamped along the clamping axis. Since the coupling member is mounted on the clamping member in a way that absorbs axial force, the coupling member and thus the pallet are also moved along the clamping axis. This allows the pallet to be clamped onto the pallet holder. A clamping force then acts between the pallet and the pallet holder.

[0013] Once the pallet is clamped onto the pallet holder, movement of the tendon in the opposite direction to the clamping movement leads to a release of the coupling element and thus also of the pallet due to the axial force-absorbing bearing of the coupling element on the tendon. Once the tendon has reached its fully released position, the effect of the clamping force on the pallet is removed. The thus-relieved coupling element is then rotated around the clamping axis in the uncoupling direction, releasing the coupling engagement between the coupling area of ​​the clamping mechanism and the counter-coupling area of ​​the pallet. The pallet can then be removed from the clamping device.

[0014] In the clamping device according to the invention, the coupling engagement between the coupling region of the clamping mechanism and the mating coupling region of the pallet is generated solely by a rotational movement, while the clamping movement for clamping the pallet is achieved by a separate axial movement of the clamping member along the clamping axis. The rotational movement for generating the coupling engagement is thus decoupled from the clamping movement. In contrast, in the prior art, for example, in the clamping device disclosed in EP 2 774 717 B1, the clamping force must also generate the rotational movement for coupling the tension member to the pallet.

[0015] In one embodiment of the clamping device, the clamping mechanism can have a first spring arrangement that applies a first spring force to the clamping member in the direction of the clamping movement, and a first pressure-medium-operated piston-cylinder arrangement for generating a force opposing the first spring force. The clamping movement along the clamping axis can be effected by the first spring force. The first spring force can generate a clamping force with which the pallet is clamped onto the pallet holder. The first pressure-medium-operated piston-cylinder arrangement serves to generate a force opposing the first spring force. If this force is greater than the first spring force, the clamping member can be moved along the clamping axis in a direction opposite to the clamping movement. This allows the clamping force acting on the pallet to be released.

[0016] A piston of the pressure-operated piston-cylinder arrangement can be arranged on a region of the tendon opposite the coupling region of the clamping mechanism. The piston can be connected to the tendon. The first spring arrangement can be supported on the piston in the clamping direction of the tendon.

[0017] The first spring arrangement may comprise a disc spring surrounding the clamping member. The disc spring may be supported on the piston in the clamping direction.

[0018] In one embodiment of the invention, the tendon can have a cylindrical outer region that forms a bearing surface for a cylindrical inner region of the coupling member. The cylinder axis of the cylindrical outer region can be aligned with the tensioning axis, so that the coupling member is rotatably mounted on the tendon about the tensioning axis. The tendon can have a cylindrical section, which can be designed as a solid cylinder or as a hollow cylinder and which has the cylindrical outer region. The coupling member can have a sleeve-shaped section. The cylindrical inner region of the sleeve-shaped section can be rotatably mounted on the cylindrical section of the tendon.

[0019] The clamping mechanism can further comprise an actuator engaging an outer region of the coupling member for adjusting a rotational position of the coupling member. The actuator can cause a rotational movement of the coupling member. The rotational position of the coupling member can be adjusted by the actuator in a coupling position for coupling the coupling region and the coupling counter-region. Furthermore, the rotational position of the coupling member can be adjusted in a decoupling position for decoupling the coupling region and the coupling counter-region.

[0020] The rotational position of the coupling member can be adjusted by moving the actuator along a linear movement path. The actuator can have an engagement region that engages with a mating engagement region of the coupling member. For example, the actuator can have a bolt-shaped portion that is movable along the linear movement path. The engagement region can be formed on the bolt-shaped portion. For example, the bolt-shaped portion can have a recess into which a projection formed on the coupling member engages in a coupling manner. Alternatively, the bolt-shaped portion can have a projection that engages in a coupling manner in a recess formed in the coupling member.

[0021] The clamping mechanism can further comprise a second spring arrangement that applies a second spring force to the actuator along the linear movement path, and a second pressure-medium-operated piston-cylinder arrangement for generating a force opposing the second spring force. If the second spring force is greater than the opposing force of the pressure-medium-operated piston-cylinder arrangement, the actuator can be moved such that the rotational position of the coupling element is set in the coupling position. If the second spring force is smaller than the opposing force of the pressure-piston-cylinder arrangement, the actuator can be moved such that the rotational position of the coupling element is set in the decoupling position.

[0022] The coupling area of ​​the clamping mechanism can have engagement surfaces with surface normals parallel to the clamping axis on teeth of an external toothing provided on the coupling area, the toothing axis of which is aligned with the clamping axis. The external toothing can have two or more teeth. For example, the external toothing can have eight teeth. The engagement surfaces serve for coupling engagement with the mating coupling area of ​​the pallet.

[0023] The engagement surfaces can be designed as undercut surfaces of the tooth flanks of the external gearing. This allows for particularly secure engagement with the mating coupling area of ​​the pallet.

[0024] In one embodiment, the tooth flanks of the external gearing facing in the direction of rotation of the coupling engagement can be convex. This can also improve the coupling engagement.

[0025] The invention further relates to the clamping device in combination with a pallet for clamping on a clamping device, wherein the coupling counter region of the pallet has engagement surfaces on teeth of an internal toothing provided on the coupling counter region, which is axially freely movable on the external toothing of the clamping mechanism before the engagement surfaces of the external toothing and the internal toothing come into rotational engagement, the toothing axis of the internal toothing is aligned with the clamping axis in the clamped state of the pallet, and surface normals of the engagement surfaces of the internal toothing run parallel to the clamping axis. Thus, an axially fixed coupling engagement can be formed between the engagement surfaces of the external toothing of the clamping device and the engagement surfaces of the internal toothing of the pallet. In this state, the surface normals of the engagement surfaces of the external toothing and the internal toothing are parallel to the clamping axis.Alternatively, the coupling area of ​​the clamping mechanism could be designed as an internal toothing and the coupling counter area of ​​the pallet as an external toothing.

[0026] The invention is described below by way of example with reference to the drawings. The figures show Fig. 1 a perspective view of a clamping device according to the invention with a pallet according to the invention clamped onto a pallet holder of the clamping device, Fig. 2 a sectional view of the Fig. 1 shown clamping device with the clamped pallet in direction AA in Fig. 1 , Fig. 3 a sectional view of the Fig. 1 shown clamping device with the clamped pallet in direction BB in Fig. 1 , Fig. 4 a sectional view of a tension member of the Fig. 1 shown clamping device, Fig. 5 a perspective view of a coupling member of the Fig. 1 shown clamping device, Fig. 6 a plan view of the Fig. 5 shown coupling element, Fig. 7 a perspective view of a coupling counter area of ​​the in Fig. 1 shown pallet from a first direction, Fig. 8 a perspective view of the Fig. 7 shown coupling counter area of ​​the pallet from a second direction, Fig. 9 a view of the in Fig. 7 shown area of ​​the pallet opposite to the clamping direction, and Fig. 10 a sectional view through the clamping device and the pallet clamped thereon, in which the coupling area and the coupling counter area are in a coupling engagement.

[0027] Fig. 1 shows a perspective view of a clamping device 1 according to the invention with a pallet 100 according to the invention clamped onto a pallet holder 2 of the clamping device 1. The clamping device 1 has a base plate 3 for connection to a support, such as a tool table, or a machine. For this purpose, openings 4 penetrating the base plate 3 are provided through which a fastening means, such as a pin or a screw, can be passed. A workpiece or a tool, for example, can be fastened to the pallet 100. For this purpose, openings 101 penetrating the base plate 3 are provided (only two of these openings are shown in Fig. 1 provided with reference symbols).

[0028] Fig. 2 shows a sectional view of the Fig. 1 shown clamping device 1 and with the clamped pallet 100 in direction AA in Fig. 1 The clamping device 1 has a base plate 3 provided with openings 4. The pallet holder 2 is arranged on the base plate 3. The pallet holder 2 has a receiving area 5 for accommodating a clamping mechanism.

[0029] The clamping mechanism comprises a tension member 6 and a coupling member 7. The tension member 6 has a cylindrical region 6a, which is concentrically surrounded in some regions by the coupling member 7. The cylindrical region 6a forms a bearing surface for a cylindrical inner region of the coupling member 7. As a result, the coupling member 7 is mounted on the tension member 6 so as to be rotatable about a clamping axis S.

[0030] At a first end region of the coupling member 7, a coupling region 8 is provided for coupling with a coupling counter-region 108 of the pallet 100. A possible configuration of the coupling region 8 with the coupling counter-region 108 is described below.

[0031] The clamping device 1 further comprises an actuator with which a rotational position of the coupling member 7 can be adjusted. By moving the actuator along a linear path of movement (in the embodiment shown, along a direction perpendicular to the plane of the drawing), the coupling member 7 can be rotated about the clamping axis S. The actuator is described in more detail below.

[0032] The tension member 6 is axially movable along the tensioning axis S. In the following, a direction directed from the pallet 100 toward the base plate 3 is referred to as a tensioning direction SR. A direction opposite to the tensioning direction SR is referred to as a relaxation direction ER.

[0033] The tension member 6 has a radial shoulder 6b at a first end region, which forms a stop for a first end region of the coupling member 7. As a result, the coupling member 7 is mounted on the tension member 6 so as to absorb axial force. A movement of the tension member 6 in the tensioning direction SR is transmitted to the coupling member 7 by the engagement of its radial shoulder with the coupling member, which then also moves in the tensioning direction SR.

[0034] The clamping device 1 further comprises a pressure-medium-operated piston-cylinder arrangement. This has a recess 11 formed in the base plate 3, which forms a cylinder 15 for a piston 12, which is arranged therein for axial movement along the clamping axis S. The piston 12 is fastened to the tension member 6 by a screw 13 and a clamping disc 16 at an end region opposite the first end region of the tension member 6. A movement of the piston 12 along the clamping axis S thus leads to a movement of the tension member 6 along the clamping axis S.

[0035] The pressure-operated piston-cylinder assembly further includes a connection 14 that allows compressed air to be supplied to a space in the cylinder 15 located between the piston 12 and the base plate 13. This allows the piston 12 to be moved in the release direction ER. The clamping disc limits the movement of the piston 12 in the clamping direction SR by contacting the base plate 3.

[0036] A first spring arrangement 20 engages on a side of the piston 12 opposite the spatial area of ​​the cylinder 15. The first spring arrangement 20 can, for example, comprise a disc spring which concentrically surrounds the tension member 6. By supplying compressed air into the spatial area of ​​the cylinder 15, a compressive force can be exerted on the piston 12 which controls the movement of the latter. If the compressive force is less than the first spring force, the piston 12 and thus the tension member 6 with the coupling member 7 mounted thereon are moved in the clamping direction SR. If the pallet 100 is coupled to the coupling member 7, the pallet 100 can be clamped onto the pallet holder 2. If the compressive force is greater than the first spring force of the first spring arrangement 20, the piston 12 and thus the tension member 6 with the coupling member 7 mounted thereon are moved in the release direction ER.If the pallet 100 is coupled to the coupling link 7, the clamping force acting on the pallet 100 can be released.

[0037] Fig. 3 is a sectional view of the Fig. 1 shown clamping device 1 and the pallet 100 in direction BB in Fig. 1 The tension member 6 is concentrically surrounded by the coupling member 7, which is arranged in the receiving area 5 of the pallet holder 2. The receiving area 5 further comprises a cylindrical channel 41, closed by a closure 43, of a second pressure-medium-operated piston-cylinder arrangement for guiding a piston 42. Compressed air can be introduced via an access into a space 45 formed between the closure 43 and the piston 42. As a result, a compressive force directed away from the closure 43 acts on the piston 12.

[0038] The piston 42 has a recess 44. A projection 7a formed on the coupling member 7 is in coupling engagement with the recess 44. When the pallet 100 is fed to the clamping device 1, a movement of the piston 42 in the cylindrical channel 41 leads to a rotational movement of the coupling member 7 into a coupling position in which the coupling region 8 of the coupling member 7 is coupled to the coupling mating region 108 of the pallet 100. A movement of the piston 42 in the opposite direction leads to a rotation of the coupling member 7 into a decoupling position in which the coupling section 8 of the clamping device 1 and the coupling mating section 108 of the pallet 100 are decoupled from one another.

[0039] The clamping device 1 further comprises a second spring arrangement 46 that engages the piston 42. The second spring arrangement 46 urges the piston 42 in a direction that causes a clockwise rotation of the coupling member 7. This preferably urges the coupling member 7 into the coupling position. If the compressive force exerted on the piston 42 is greater than the second spring force, the coupling member 7 coupled to the piston 42 is rotated into the uncoupling position. If the compressive force exerted on the piston 42 is less than the second spring force, the coupling member 7 coupled to the piston 42 is rotated into the coupling position.

[0040] Fig. 4 is a sectional view of the tension member 6 of the Fig. 1 shown clamping device 1. The tension member 6 has the cylindrical area 6a, which forms a bearing surface for the cylinder-shaped inner area of ​​the coupling member 7. Further shows Fig. 4 the radial shoulder 6b formed at the first end region, which forms a stop for the first end region of the coupling member 7. A second radial shoulder 6c forms a stop for a sleeve 17, which has a radial shoulder at its axial end facing the first end region of the tension member 6, on which shoulder the coupling member 7 is supported. As a result, the coupling member 7 is axially fixedly mounted on the tension member 6 between this shoulder and the shoulder 6b formed at the first end region, in that the sleeve 17 bears against the piston 12 at its axial end opposite its shoulder. The tension member 6 also has a screw receptacle 6d for a screw 13.

[0041] Fig. 5 is a perspective view of the coupling link 7 of the Fig. 1 shown clamping device 1, and Fig. 6 is a top view of the Fig. 5 shown coupling link 7. As in Fig. 5 and Fig. 6 As can be seen, the coupling area 8 has an external toothing 81 with teeth 82. Tooth flanks 84 of the teeth 83 have undercut surfaces, which form engagement surfaces 83 for engagement with a coupling counter-area 108 of the pallet 100. When the coupling member 7 is rotatably mounted on the tension member 6, the toothing axis is aligned with the clamping axis S, and surface normals of the engagement surfaces 83 run parallel to the clamping axis S. Furthermore, in the Fig. 5 and 6 In the embodiment of the coupling region 8 shown, the tooth flanks 84 of the external toothing 81 pointing in the direction of rotation of the coupling engagement are convexly shaped.

[0042] Fig. 7 is a perspective view of a coupling counter area 108 of the Fig. 1 shown pallet 100 from a first direction. Fig. 8 is a perspective view of the Fig. 7 shown coupling counter area 108 of the pallet 100 from a second direction, and Fig. 9 a view of the Fig. 7 shown coupling counter-area 108 of the pallet 100 against the clamping direction S.

[0043] The coupling counter-area 108 of the pallet 100 has an internal toothing 109 with teeth 110 having engagement surfaces 111. Before the engagement surfaces 83 of the external toothing 81 of the clamping device 1 engage the engagement surfaces 111 of the internal toothing 109 in a rotational manner, the internal toothing 109 is freely movable on the external toothing 83. Thus, the pallet 100 can be advanced to the clamping device 1. In the clamped state of the pallet 100, the toothing axis of the internal toothing 109 is aligned with the clamping axis S, and the surface normals of the engagement surfaces are parallel to the clamping axis S. A sectional view of the clamping device 1 with the pallet 100 clamped thereon, in which the teeth 82 of the external toothing 83 of the clamping device 1 are in coupling engagement with the teeth 110 of the internal toothing 109, is shown in Fig. 10 shown. Liste der Bezugszeichen

[0044] 1 Clamping device 2 Pallet holder 3 Base plate 4 Opening 5 Mounting area 6 Tension member 6a Cylindrical area 6b Radial shoulder 6c Second radial shoulder 6d Screw holder 7 Coupling link 7a Projection 8 Coupling area 11 Recess 12 Piston 13 Screw 14 Connection 15 Cylinder 16 Clamping disc 17 Sleeve 20 First spring arrangement 41 Cylindrical channel 42 Piston 43 Closure 44 Recess 45 Space 46 Second spring arrangement 81 External toothing 82 Teeth 83 Engagement surfaces 84 Tooth flanks 100 Pallet 101 Opening 108 Coupling counter area 109 Internal toothing 110 Teeth 111 Engagement surfaces SS Clamping axis SR Clamping direction ER Unclamping direction

Claims

1. A clamping device (1) for clamping a pallet (100) on a pallet receptacle (2) of the clamping device (1), comprising a clamping mechanism formed to carry out a clamping movement of an axially movable clamping member (6) running along a clamping axis (S) and a rotational movement of a radially extending coupling region (8) of the clamping mechanism running about the clamping axis (S), wherein the rotational movement is used for the axially fixed coupling engagement of the coupling region (8) of the clamping mechanism with a coupling counter region (108) of the pallet (100), and the clamping movement is used to clamp the coupled pallet (100) on the pallet receptacle (2), characterised in that the coupling region (8) of the clamping mechanism is formed on a coupling member (7) which is rotatably mounted on the clamping member (6) and absorbs axial force.

2. The clamping device (1) according to claim 1, characterised in that the clamping mechanism has a first spring arrangement (20) which applies a first spring force to the clamping member (6) in the direction of the clamping movement, and a first pressure-medium-operated piston-cylinder arrangement (11, 12, 15) for generating a force opposing the first spring force.

3. The clamping device (1) according to claim 2, characterised in that a piston (12) of the pressure-medium-operated piston-cylinder arrangement (11, 12, 15) is arranged on a region of the clamping member (6) opposite the coupling region (8) of the clamping mechanism.

4. The clamping device (1) according to one of claims 2 and 3, characterised in that the first spring arrangement (20) has a disc spring surrounding the clamping element (6).

5. The clamping device (1) according to one of the preceding claims, characterised in that the clamping member (6) has a cylinder-jacket-shaped outer region (6a) which forms a bearing surface for a cylinder-jacket-shaped inner region of the coupling member (7).

6. The clamping device (1) according to claim 5, characterised in that the clamping mechanism further includes an actuator (42) acting on an outer region (7a) of the coupling member (7) for adjusting a rotational position of the coupling member (7).

7. The clamping device (1) according to claim 6, wherein the rotational position of the coupling member (7) is adjustable by a movement of the actuator (42) along a linear movement path.

8. The clamping device (1) according to claim 7, characterised in that the clamping mechanism further includes a second spring arrangement (46) which applies a second spring force to the actuator (42) along the linear movement path, and a second pressure-medium-operated piston-cylinder arrangement (41, 42) for generating a force opposing the second spring force.

9. The clamping device (1) according to one of the preceding claims, characterised in that the coupling region (8) of the clamping mechanism has engagement surfaces (83) having surface normals parallel to the clamping axis (S) on teeth (82) of an external toothing (81) provided on the coupling region (8) and whose toothing axis is aligned with the clamping axis (S).

10. The clamping device (1) according to claim 9, characterised in that the engagement surfaces (83) are designed as undercut surfaces of tooth flanks (84) of the external toothing (81).

11. The clamping device (1) according to claim 9 or 10, characterised in that the tooth flanks (84) of the external toothing (81) facing in the direction of rotation of the coupling engagement are convexly shaped.

12. The clamping device (1) according to one of claims 9 to 11, comprising a pallet (100) for clamping on the clamping device (1), characterised in that the coupling counter-region (108) of the pallet (100) has engagement surfaces (111) on teeth (110) of an internal toothing (109) which is provided on the coupling counter-region (108) and is axially freely movable on the external toothing (81) of the clamping mechanism before the engagement surfaces (83) of the external toothing (81) and of the internal toothing (109) come into rotational coupling engagement, the toothing axis of the internal toothing (109) is aligned with the clamping axis (S) in the clamped state of the pallet (100), and surface normals of the engagement surfaces (111) of the internal toothing (109) run parallel to the clamping axis (S).