Fastening device for fastening a processing tool to a machine tool, tool arrangement, tool magazine, and method for operating a machine tool

Abstract

A fastening device for fastening a processing tool to a machine tool, in particular to a press device, comprises at least one locating body, against which the processing tool can be clamped, a clamping unit for the releasable clamping of the processing tool to the at least one counter clamping body, and a locking connection for the releasable connection of the clamping unit to the at least one counter clamping body.

Claims

1. A fastening device for fastening a processing tool to a machine tool, comprising: at least one counter clamping body, against which the processing tool can be clamped; a clamping unit for releasably clamping the processing tool to the at least one counter clamping body; and a locking connection for releasably connecting the clamping unit to the at least one counter clamping body.

2. The fastening device according to claim 1, wherein the processing tool is fastened to a press device.

3. The fastening device according to claim 1, wherein the clamping unit and at least one of at least one locking element of the locking connection or at least one locking engagement feature of the locking connection are mounted on a closing body.

4. The fastening device according to claim 1, wherein the locking connection comprises a latching connection for the latching connection of the clamping unit to the at least one counter clamping body.

5. The fastening device according to claim 1, further comprising a linear guide for limiting movability of the clamping unit relative to the at least one counter clamping body along a joining direction.

6. The fastening device according to claim 1, wherein the clamping unit has at least one spring means, via which a clamping force for clamping the processing tool is transmitted.

7. The fastening device according to claim 1, wherein the locking connection comprises at least two locking elements or the clamping unit comprises at least two clamping elements for clamping the processing tool to the at least one locating body.

8. The fastening device according to claim 1, wherein the clamping unit comprises an actuating engagement feature for manually operated movement of the fastening device between a clamping position and an open position.

9. The fastening device according to claim 1, wherein the clamping unit comprises an eccentric shaft having a clamping eccentric portion for converting a drive torque into a clamping force for clamping the processing tool.

10. The fastening device according to claim 1, wherein the clamping unit has a stable position in a clamping position, in which the processing tool is clamped to the counter clamping body.

11. The fastening device according to claim 1, wherein the clamping unit comprises at least one deflection means for deflecting a driving movement by at least 45 into a clamping movement acting on the processing tool.

12. The fastening device according to claim 1 comprising at least one retaining means for fixing the clamping unit in a clamping position or an open position.

13. The fastening device according to claim 1, wherein the processing tool is a press die or a forming die.

14. The fastening device according to claim 13, wherein the processing tool is a punching die.

15. A tool arrangement for a machine tool, comprising: the fastening device according to claim 1; and a processing tool for processing a workpiece, wherein the clamping unit is releasably connected to the at least one counter clamping body by means of the locking connection, and wherein the processing tool is releasably clamped to the at least one counter clamping body by means of the clamping unit.

16. The tool arrangement as claimed in claim 15, wherein the machine tool is a press device.

17. A tool magazine, comprising: a magazine main body; and a plurality of tool arrangements according to claim 13 mounted on the magazine main body.

18. A method for operating a machine tool, comprising the following steps: providing a machine tool having a fastening device as in claim 1, providing a processing tool for processing a workpiece, arranging the processing tool at the at least one counter clamping body, arranging the clamping unit at the at least one counter clamping body, closing the locking connection to connect the clamping unit to the at least one counter clamping body, clamping the processing tool to the at least one counter clamping body by the clamping unit, and processing the workpiece by the processing tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG. 1 shows a schematic side view of a machine tool having a tool magazine that has a plurality of tool arrangements, each having one processing tool for processing a workpiece.

[0051] FIG. 2 shows an exploded illustration of the tool arrangement in FIG. 1 with the processing tool and a fastening device for connecting the processing tool to the magazine main body.

[0052] FIG. 3 shows a front view of the tool arrangement in FIG. 1, wherein a clamping unit and a locking connection of the fastening device are arranged in an open position.

[0053] FIG. 4 shows a plan view of the tool arrangement in FIG. 1.

[0054] FIG. 5 shows a detail of the clamping unit and of the locking connection according to the detail V in FIG. 4, wherein concealed edges are illustrated by dashed lines and wherein the clamping unit has an eccentric shaft, which acts on the processing tool via two clamping elements.

[0055] FIG. 6 shows a rear view of the eccentric shaft in FIG. 5, wherein the eccentric shaft comprises a bearing portion, a clamping eccentric portion and an opening eccentric portion.

[0056] FIG. 7 shows a bottom view of the eccentric shaft in FIG. 5.

[0057] FIG. 8 shows a front view of the eccentric shaft in FIG. 5 with an actuating engagement feature for moving the fastening device between a clamping position and an open position.

[0058] FIG. 9 shows a section through the eccentric shaft along section line IX-IX in FIG. 8 with a retaining means engagement feature for fixing the clamping unit in the clamping position.

DETAILED DESCRIPTION

[0059] FIG. 1 illustrates a machine tool 1 having a frame structure 2, a tool magazine 3 connected thereto and having a plurality of processing tools 4, a work table 5 for supporting a workpiece 6 to be processed, and a positioning device 7 for moving the workpiece 6 relative to the work table 5. The workpiece 6 is a sheet, in particular a metal sheet. The positioning device 7 comprises a positioning drive 8, which is connected to a clamping means 9. The workpiece 6 is secured reversibly on the clamping means 9 and can be moved relative to the work table 5 by means of the positioning drive 8.

[0060] An actuating device 11 is arranged on a frame upper part 10 of the frame structure 2. The actuating device 11 comprises a ram 12 for driving a processing tool 4, which is designed as a punch 13, arranged below the ram 12. A processing tool 4 designed as a punching die 14 is arranged on the tool magazine 3. The punching die 14 is arranged opposite the punch 13 in relation to the workpiece 6. The punch 13 and the punching die 14 interact as a tool pair 15 during the processing of the workpiece 6.

[0061] A plurality of tool arrangements 17 is mounted on a magazine main body 16 of the tool magazine 3. The tool arrangements 17 each comprise one of the punching dies 14 and a fastening device 18 for connecting the punching die 14 to the magazine main body 16 of the machine tool 1.

[0062] The tool magazine 3 is connected in a rotatably drivable manner to the frame structure 2. The active tool pair 15 can be selected from a plurality of tool pairs 15 arranged on the tool magazine 3, and, for processing the workpiece 6, can be positioned in a vertical direction below the ram 12 by driving the tool magazine 3 in rotation.

[0063] One of the tool arrangements 17 is shown in further detail in FIG. 2. The tool arrangement 17 comprises the fastening device for fastening the processing tool 4 designed as a punching die 14 on the machine tool 1 designed as a press device, in particular as a turret punch press. For this purpose, the fastening device 18 has a fastening main body 19, a counter clamping body 20 mounted thereon, and a closing body 21, which can be connected reversibly to the counter clamping body 20. The fastening main body 19 is rotatably mounted on the magazine main body 16 and can be driven in rotation relative thereto by means of a machine drive (not illustrated). The counter clamping body 20 is connected to the fastening main body 19 for conjoint rotation therewith. A main body connection between the fastening main body 19 and the counter clamping body 20 comprises a positive joint designed as a slot and key joint 22 for connecting the fastening main body 19 to the counter clamping body 20 for conjoint rotation about a processing direction 23. The processing direction 23 is oriented parallel to a direction of action of the ram 3. The main body connection furthermore comprises a plurality of screwed joints 24.

[0064] The counter clamping body 20 has a base flange 25 and an arc-shaped locating collar 26 connected thereto. The screwed joints 24 extend through the base flange 25. The locating collar 26 forms a contact surface 27 for clamping to the processing tool 3.

[0065] A clamping unit 28 and two locking elements 29 of a locking connection 30 are mounted in a captive manner on the closing body 21. The locking elements 29 can be mounted on the closing body 21 in such a way that they can be moved along an actuating direction 23a parallel to the processing direction 23. By means of locking springs 31, the locking elements 29 are preloaded in the direction of the counter clamping body 20. The locking elements 29 are mounted on a lock carrier 32. The lock carrier 32 interacts as a stop with the closing body 21 and limits the movability of the locking elements 29 along the actuating direction 23a. The locking elements 29 are mounted on the lock carrier 32 by means of fixing pins 33 oriented perpendicularly to the actuating direction 23a.

[0066] In an open state of the locking connection 30, the lock carrier 32 is arranged at a distance from the closing body 21. In a clamping state of the locking connection 30, the lock carrier 32 makes contact with the closing body 21.

[0067] The locking elements 29 have latching chamfers 34. The latching chamfers 34 ensure latching closure of the locking connection 30 to connect the clamping unit 28 to the counter clamping body 20. The lock carrier 32 is designed as an arc-shaped strip, which, together with the closing body 21 and the counter clamping body 20, forms a unit that is substantially rotationally symmetrical around the actuating direction 23.

[0068] The clamping unit 28 comprises an eccentric shaft 35 and two clamping elements 36 interacting therewith. The clamping elements 36 are each mounted so as to be rotatable about a deflection axis 37 oriented parallel to the actuating direction 23. By rotation of the clamping elements 36 around the deflection axis 37, they can be moved between the clamping position, in which the processing tool 4 is clamped against the counter clamping body 20, and an unlatched position, in which the processing tool 4 is released. A clamping force F.sub.S transmitted by the clamping elements 36 is perpendicular to the actuating direction 23.

[0069] The eccentric shaft 35 is rotatably mounted in a shaft bore 38 of the closing body 21. The eccentric shaft 35 interacts with the two clamping elements 36 via a clamping eccentric portion 39. The eccentric shaft 35 comprises an actuating engagement feature 40, which is designed as a positive locking profile, in particular as an internal hexagon profile. By driving the eccentric shaft 35 in rotation via the actuating engagement feature 40, the clamping forces F.sub.S can be applied to the processing tool 4 via the clamping elements 36.

[0070] The clamping unit 28 furthermore comprises a torsion spring 41 operatively connected to the eccentric shaft 35. The torsion spring 41 is designed as a leg spring and preloads the eccentric shaft 35 in the direction of the clamping position.

[0071] The clamping unit 28 furthermore comprises a retaining means 42 for fixing the eccentric shaft 35 in the clamping position or in the open position. The retaining means 42 is designed as a pressure piece. In the clamping position or in the open position, the retaining means 42 in each case interacts with a retaining means engagement feature 43 of the eccentric shaft 35.

[0072] The fastening device 18 comprises a linear guide 44 for limiting the movability of the clamping unit 28 relative to the counter clamping body 20 along a joining direction 45. The joining direction 45 is oriented substantially parallel to the clamping force F.sub.S. The linear guide 44 comprises two T-shaped guide slots 46 formed in the counter clamping body 20, in particular in the base flange 25. Two sliding elements 47 of the linear guide 44 for positive interaction with the guide slots 46 are mounted on the closing body 21. The linear guide 46 comprises a plug-in joint 48 with guide holes 49 in the counter clamping collar 26 and guide pins 50 that can be inserted therein on the closing body 21.

[0073] The fastening device 18 furthermore has two disengagement springs 51. The disengagement springs 51 exert disengagement forces F.sub.A between the closing body 21 and the counter clamping body 20 in order to move the closing body 21 counter to the joining direction 45 relative to the counter clamping body 20. The disengagement springs 51 are mounted on the counter clamping body 20, in particular being inserted into the locating collar 26.

[0074] In FIG. 3, the tool arrangement 17 is illustrated in a front view. The closing body 21 has been moved along the joining direction 45, and the closing body 21 is in contact with the locating collar 26. The sliding elements 47 are in engagement with the guide slots 46, and the guide pins 50 are in engagement with the guide holes 49. The lock carrier 32 and the locking elements 29 connected thereto are arranged in the unlatched position.

[0075] The clamping unit 28 is shown in greater detail in FIG. 4 and FIG. 5. The locking connection 30 has been moved into the closed position, and the eccentric shaft 35 is in the clamping position. The clamping eccentric portion 39 of the eccentric shaft 35 acts on the respective clamping element 36 in each case via a linear contact body 52. The linear contact bodies 52 are designed as strips of rectangular cross section and are produced from a sliding bearing material, in particular from bronze.

[0076] The eccentric shaft 35 is designed to convert a drive torque M.sub.A into eccentric forces F.sub.E oriented perpendicularly to an eccentric axis 53. The eccentric forces F.sub.E are oriented substantially perpendicularly to the clamping forces F.sub.S. The clamping elements 36 are designed as deflection means 54 for deflecting the eccentric forces F.sub.E to produce the clamping forces F.sub.S. For this purpose, the clamping elements 36 are mounted so as to be rotatable about the deflection axes 37, as described above.

[0077] The clamping elements 36 comprise spring means 55 for the resilient transmission of the clamping forces F.sub.S to the processing tool 4. The spring means 55 are designed as bending springs, in particular in the form of solid body joints. Each of the clamping elements 36 comprises three of the spring means 55. In particular, the clamping elements 36 are of slotted design to bring about the spring action, wherein a slot base of the respective slot is enlarged to form a hole in order to promote the spring action and reduce stress peaks.

[0078] The eccentric shaft 35 is shown in greater detail in FIG. 6 to FIG. 9. The eccentric shaft 35 comprises, in succession, an opening eccentric portion 56, a bearing portion 57 for the rotatable mounting of the eccentric shaft 35 on the shaft bore 38, the clamping eccentric portion 39, and a torsion spring engagement feature 58 for connection to the torsion spring 41 for conjoint rotation therewith about the eccentric axis 53.

[0079] The eccentric shaft 35 comprises a rotation stop 59. The rotation stop 59 is arranged on the opening eccentric portion 56. In the clamping position, the rotation stop 59 comes into contact with the base flange 25 and prevents rotation of the eccentric shaft 35 beyond the clamping position.

[0080] The clamping eccentric portion 39 comprises two eccentric cams 60. A clamping radius R.sub.S in a clamping region 61 of the respective eccentric cam 60 is greater than an opening radius R.sub.O of the clamping eccentric portion 39 with respect to the eccentric axis 53. A dead centre radius R.sub.T of a dead centre 62 is, in turn, greater than the clamping radius R.sub.S. In the clamping position, the clamping region 61 is in contact with the linear contact body 52. By virtue of the fact that the opening radius R.sub.O is greater than the clamping radius R.sub.S, an energy peak has to be overcome during the movement of the eccentric shaft 35 between the clamping position and the open position. The clamping position thus represents a stable position of the eccentric shaft 35.

[0081] In FIG. 9, the eccentric shaft 35 is illustrated in section. A thread 63 is used to fasten the eccentric shaft 35 on the closing body 21 by means of a connecting screw 64. The torsion spring 41 is rotatably mounted on a screw stem of the connecting screw 64.

[0082] The operation of the machine tool 1, of the tool magazine 3, of the tool arrangement 17 and of the fastening device 18 is as follows:

[0083] The counter clamping body 20 is connected to the magazine main body 16 for conjoint rotation therewith via the fastening main body 19. The closing body 21 has been removed from the counter clamping body 20. The clamping unit 28 is in the open position. The spring means 55 are relaxed, and the retaining means 42 is in engagement in one of the retaining means engagement features 43.

[0084] The punching die 14 is inserted into the counter clamping body 20 from the side, in particular along the joining direction 45. The punching die 14 rests against the contact surface 27. Insertion of the processing tool 4 from the side ensures that the loading of the processing tool is possible even if there is not sufficient installation space for vertical loading in a vertical direction.

[0085] The closing body 21 is guided by the linear guide 44 along the joining direction 45 in the direction of the counter clamping body 26. During this process, the sliding elements 47 engage in the guide slots 46, and the guide pins 50 engage in the guide holes 49.

[0086] The latching chamfers 34 come into contact with the fastening body 19. Moving the closing body 21 further in the joining direction 45 brings about movement of the locking elements 29 into the unlatched position, in particular counter to the actuating direction 23. The locking springs 31 are stressed. The lock carrier 32 moves out of contact with the closing body 21 and is raised upwards. The disengagement springs 51 come into contact with the closing body 21 and are stressed.

[0087] In a plan view, the locking elements 29 come into overlap with locking holes 65 in the counter clamping body 20, in particular in the fastening main body 19, in particular along the actuating direction 23. The locking elements 29 latch into the locking holes 65. During this process, the locking elements 29 are moved along the actuating direction 23a by means of the locking springs 31, together with the lock carrier 32. The lock carrier 32 comes into contact with the closing body 21. The locking connection 30 is in the closed position. An upper edge of the lock carrier 32 is arranged flush with an upper edge of the closing body 21. This arrangement indicates to the user that the locking connection 30 is in the closed position.

[0088] An actuating tool, in particular a hexagon wrench, is brought into engagement with the actuating engagement feature 40. Via the actuating engagement feature 40, a drive torque M.sub.A is transmitted to the eccentric shaft 35, whereby the eccentric shaft 35 is rotated. The respective linear contact body 52 comes into contact with the respective eccentric cam 60. The eccentric forces F.sub.E are thereby transmitted to the linear contact body 52. Via the deflection means 54, the respective eccentric force F.sub.E is converted into the clamping force F.sub.S. During this process, the clamping force F.sub.S is transmitted via the deflection means 54, and the spring means 55 are stressed.

[0089] The linear contact body 52 comes into contact with the dead centre 62. The maximum clamping force F.sub.S is achieved. As the eccentric shaft 35 is rotated further, the linear contact body 52 comes into contact with the clamping region 61. During this process, the clamping force F.sub.S is slightly reduced, and the eccentric shaft 35 is in a stable position. The clamping position has been reached.

[0090] The rotation stop 59 is in contact with the fastening main body 19. Further rotation of the eccentric shaft 35 is thereby prevented. In particular, the eccentric shaft 35 is fixed in the clamping position by the dead centre 62 and the rotation stop 59.

[0091] The punching die 14 is clamped to the counter clamping body 20 by means of the clamping force F.sub.S. The punching die 14 can be used to process a workpiece 6. The eccentric shaft 35 is additionally secured in the clamping position by means of the retaining means 42, which is in engagement with the retaining means engagement feature 43 of the eccentric shaft 35.

[0092] The workpiece 6 is arranged on the work table 5 and connected to the clamping means 9. The tool pair 15 is arranged below the ram 12, and the workpiece 6 is processed by the tool pair 15, being driven by the actuating device 11.

[0093] To remove the punching die 14 from the fastening device 18, the eccentric shaft 35 is moved into the open position by means of the actuating tool via the actuating engagement feature by the application of an opposite drive torque M.sub.A. By means of the drive torque M.sub.A introduced, the eccentric shaft 35 is rotated, wherein the dead centre 62 is overcome. The linear contact body 52 is moved into the region of the opening radius R.sub.O, and the spring means 55 are relaxed. The punching die 14 is free from clamping forces F.sub.S. The clamping unit 28 is in the open position. To secure the open position, the retaining means 42 engages in the associated retaining means engagement feature 43.

[0094] To release the locking connection 30, the eccentric shaft 35 is rotated further. The torsion spring 41 is stressed. The opening eccentric portion 56 comes into contact with the lock carrier 32. Further rotation of the eccentric shaft 35 results in raising of the lock carrier 32 together with the locking elements 29. The locking connection 30 is in the unlatched position. The locking elements 29 disengage from the locking holes 65.

[0095] The disengagement forces F.sub.A provided by the disengagement springs 51 result in movement of the closing body 21 counter to the joining direction 45. The locking elements 29 move out of overlap with the locking holes 65 along the actuating direction 23a. The actuating tool can be removed from the actuating engagement feature 40. The closing body 21 is separated from the counter clamping body 20 along the linear guide 45. The torsion spring 41 causes movement of the eccentric shaft 35 back into the open position, and the retaining means 42 secures the eccentric shaft 35 in the open position.

[0096] The punching die 14 can be removed from the fastening device 18. The machine tool 1 is in the initial position again. The fastening device 18 is once again ready for the loading of a punching die 14.

[0097] The tool magazine 3, the tool arrangement 17 and the fastening device 18 advantageously ensure that the processing tool 4 can be loaded into the machine tool 1 in a particularly simple and effective manner. By virtue of the fact that the clamping unit 28 is connected to the counter clamping body 20 by means of a locking connection 30, the processing tool 4 can be connected to the machine tool 1 in a manner which is particularly efficient in terms of time. The design of the locking connection 30 as a latching connection ensures particularly simple fastening of the processing tool 4 on the machine tool 1, in particular with just one hand. The release of the locking connection 30 by means of the eccentric shaft 35, and the movement of the closing body 21 into a position at a distance from the counter clamping body 20 by means of the disengagement springs 51, make the fastening device 18 even easier to handle. The tool magazine 3, the tool arrangement 17 and the fastening device 18 ensure particularly time-efficient changing of processing tools 4 and particularly reliable connection of the processing tool 4 to the machine tool 1 and thus economical operation of the machine tool 1.