MACHINE TOOL AND METHOD FOR OPERATING THE MACHINE TOOL

Description

[0001] The invention relates to a machine tool, a method for operating the machine tool and a machining system comprising at least two machine tools.

[0002] So-called twin-spindle machines are known from WO 2005 / 025801 A1 and WO 00 / 37213 A2. In such twin-spindle machines, two workpieces can be machined simultaneously using a tool inserted into each of the tool spindles. Both tool spindles, and thus both tools, are moved synchronously in the three axes of the coordinate system, so that identical machining operations are performed on both workpieces.

[0003] The double-spindle machines known from WO 2005 / 025801 A1 and WO 00 / 37213 A2 have the disadvantage that, due to their design, the maximum length of the workpiece that can be machined is limited.

[0004] An image registered as D1 in the granting procedure shows the "Xflex Twin" machine tool from Etxetar, as seen on the etxetar.com website on June 1, 2020. An image registered as D1 in the granting procedure shows a first pair of work spindles arranged one above the other and a second pair of work spindles arranged one above the other, as seen on the etxetar.com website on March 18, 2020. An image registered as D1 in the granting procedure shows work spindles arranged one above the other, as seen on the etxetar.com website on October 15, 2019. An image registered as D1 in the granting procedure shows two work spindles arranged side by side, as seen on the etxetar.com website on October 15, 2019.

[0005] US6203478B1 discloses a machine tool with two spindles arranged one above the other for machining two crankshafts mounted one above the other.

[0006] The object of the present invention was to overcome the disadvantages of the prior art and to provide an improved machine tool, an improved method for operating the machine tool, and an improved machining system.

[0007] This object is achieved by a device and a method according to the claims. According to the invention, a machine tool is designed according to the appended claim 1. The machine tool according to the invention offers the advantage that long workpieces can be easily machined with high efficiency.

[0008] According to the invention, the machine tool is designed such that the first work spindle can be moved in the Z-axis by means of a first spindle adjustment device and that the second work spindle can be moved in the Z-axis by means of a second spindle adjustment device, wherein the first work spindle and the second work spindle can be moved independently of one another. This has the advantage that the first work spindle and the second work spindle can carry out machining operations independently of one another, so that two differently designed workpieces can be machined simultaneously in the machine tool. Furthermore, it can be provided that the first work spindle and / or the second work spindle are arranged on the machine frame by means of a pivot bearing so as to be pivotable with respect to the latter. The first spindle axis or the second spindle axis can thus be pivoted from the horizontal position into a position at an angular difference therefrom.

[0009] Furthermore, it can be provided that in addition to the first work spindle and the second work spindle, a third work spindle is formed, wherein the first work spindle, the second work spindle and the third work spindle are arranged vertically one above the other.

[0010] This has the advantage that the efficiency of the machine tool can be further increased.

[0011] Another advantageous embodiment provides that the workpiece clamping device comprises at least a first workpiece table and a second workpiece table, wherein the first workpiece table is pivotably mounted about a first pivot axis aligned parallel to a horizontal X-axis, and the second workpiece table is pivotably mounted about a second pivot axis aligned parallel to the X-axis, and wherein the first work spindle is assigned to the first workpiece table and the second work spindle is assigned to the second workpiece table. This offers the advantage that the workpiece(s) to be machined can be machined with high precision and good efficiency.

[0012] Furthermore, it can be provided that the workpiece clamping device comprises at least a first workpiece table and a second workpiece table, wherein the first workpiece table is pivotably mounted about a first pivot axis which is aligned parallel to a horizontal X-axis and the second workpiece table is pivotably mounted about a second pivot axis which is aligned parallel to the X-axis and that the first work spindle is assigned to the first workpiece table and the second work spindle is assigned to the second workpiece table and that a fourth work spindle is formed which is assigned to the first workpiece table and that a fifth work spindle is formed which is assigned to the second workpiece table,wherein the first work spindle and the fourth work spindle are arranged at a distance from each other with respect to the horizontal X-axis, and wherein the second work spindle and the fifth work spindle are arranged at a distance from each other with respect to the horizontal X-axis. This results in an increase in the efficiency of the machine tool.

[0013] Furthermore, it can be provided that the workpiece clamping device comprises at least a first rear workpiece table and a second rear workpiece table, wherein the first rear workpiece table is pivotably mounted about a first rear pivot axis which is aligned parallel to a horizontal X-axis, and the second rear workpiece table is pivotably mounted about a second rear pivot axis which is aligned parallel to the X-axis, and that the first workpiece table and the second workpiece table are arranged on a first side of a pivot bridge which is pivotably mounted about a pivot bridge axis aligned parallel to the X-axis, and that the first rear workpiece table and the second rear workpiece table are arranged on a second side of the pivot bridge, wherein depending on the pivot position of the pivot bridge The first work spindle and the fourth work spindle are assigned to the first workpiece table, and the second work spindle and the fifth work spindle are assigned to the second workpiece table, or the first work spindle and the fourth work spindle are assigned to the first rear workpiece table, and the second work spindle and the fifth work spindle are assigned to the second rear workpiece table. This results in an increase in the efficiency of the machine tool.

[0014] Furthermore, it can be provided that a fourth workpiece table and a fifth workpiece table are arranged on the machine frame, wherein the first workpiece table and the fourth workpiece table are arranged at a distance from one another with respect to the horizontal X-axis, and wherein the second workpiece table and the fifth workpiece table are arranged at a distance from one another with respect to the horizontal X-axis, wherein the first work spindle is assigned to the first workpiece table, and wherein the second work spindle is assigned to the second workpiece table, and wherein the fourth work spindle is assigned to the fourth workpiece table, and wherein the fifth work spindle is assigned to the fifth workpiece table. This brings about an increase in the efficiency of the machine tool.

[0015] According to a further development, it is possible for the workpiece clamping device to comprise at least a first rear workpiece table and a second rear workpiece table, wherein the first rear workpiece table is pivotably mounted about a first rear pivot axis which is aligned parallel to a horizontal X-axis, and the second rear workpiece table is pivotably mounted about a second rear pivot axis which is aligned parallel to the X-axis, and that the first workpiece table and the second workpiece table are arranged on a first side of a pivot bridge which is pivotably mounted about a pivot bridge axis aligned parallel to the X-axis, and that the first rear workpiece table and the second rear workpiece table are arranged on a second side of the pivot bridge, wherein depending on the pivot position of the pivot bridge The first work spindle is assigned to the first workpiece table and the second work spindle is assigned to the second workpiece table, or the first work spindle is assigned to the first rear workpiece table and the second work spindle is assigned to the second rear workpiece table. This has the advantage that workpieces clamped on the first workpiece table or the second workpiece table can be machined, while the already machined workpieces are removed from the first rear workpiece table or the second rear workpiece table and new workpiece blanks are inserted. This further increases the efficiency of the machine tool.Such a design of the workpiece clamping device in conjunction with the vertically stacked first work spindle and second work spindle brings surprising advantages in terms of accessibility and thus in the interchangeability of the already machined workpieces.

[0016] In particular, it can be provided that, for changing the workpieces, the swivel bridge is positioned in such a swivel position that the first workpiece table and the second workpiece table are arranged next to one another at a horizontal distance. This has the advantage that the workpieces can be changed easily. In particular, lifting devices such as chains or other traction devices that can only absorb tensile forces can be used to change the workpieces. Furthermore, this measure makes the workpiece tables accessible to a workpiece changing device arranged overhead. This can, for example, be a rail-guided workpiece changing device.

[0017] Furthermore, it may be expedient for the swivel bridge axis to be arranged centrally between the first swivel axis, the second swivel axis, the first rear swivel axis, and the second rear swivel axis. This has the advantage that the first workpiece table and the first rear workpiece table, or the second workpiece table and the second rear workpiece table, assume the same position when swiveled into the machining space of the machine tool, and thus the workpieces can be machined without any necessary compensation of the position of the work spindles or the swivel bridge.

[0018] Furthermore, it can be provided that a partition wall is formed between the first side of the pivoting bridge and the second side of the pivoting bridge, wherein, when the machine tool is in the machining state, the partition wall separates a working area of ​​the machine tool from an outer area of ​​the machine tool. This has the advantage that the partition wall can close off the working area of ​​the machine tool, thus increasing the machine tool's safety. Furthermore, this measure can reduce the machine tool's noise emissions.

[0019] Furthermore, it can be provided that the distance between the first work spindle and the second work spindle is adjustable along a vertical Y-axis by means of a spindle distance compensation device. This has the advantage that any thermal expansion of the machine tool can be compensated, so that the relative position of the first work spindle to the first workpiece table and the second work spindle to the second workpiece table remains the same throughout the entire machining process of the machine tool.

[0020] According to a particular embodiment, it is possible for a tool magazine to be arranged at a longitudinal end of the workpiece clamping device, wherein the tool magazine comprises a chain magazine, wherein a straight run of the chain magazine is vertically aligned, wherein the first work spindle and the second work spindle are displaceable relative to the straight run of the chain magazine, wherein a distance between the first work spindle and the second work spindle corresponds to a pitch or a multiple of the pitch of the chain magazine. It is advantageous here that the first work spindle and the second work spindle can be moved relative to the chain magazine in order to deposit the no longer required work tool and to accommodate a new machining tool.Because the distance between the first work spindle and the second work spindle corresponds to a pitch or a multiple of a pitch of the chain circulating magazine, the machining tools held in the first work spindle and second work spindle can be deposited at the same time or new machining tools can be picked up at the same time in a wider step.

[0021] Furthermore, it can be provided that an additional tool magazine is arranged at a second longitudinal end of the workpiece clamping device, wherein the additional tool magazine is designed as a mirror image of the tool magazine. This results in an increase in the efficiency of the machine tool.

[0022] As an alternative design variant to a straight run of the recirculating chain magazine in the area of ​​the two work spindles, it can also be provided that the recirculating chain magazine has a guideway between the two work spindles that deviates from a straight line, such as a curve or an omega-shaped or trapezoidal chain track. Thus, the distance between the first work spindle and the second work spindle does not have to correspond to a pitch or a multiple of the pitch of the recirculating chain magazine, but a different pitch can also be selected. Here, too, it can be provided that the pitch of the recirculating chain magazine is selected such that the respective provision positions of the recirculating chain magazine are arranged at a distance between the first work spindle and the second work spindle.

[0023] According to the invention, a method for operating a machine tool is provided. The machine tool comprises a machine frame, a first work spindle mounted for rotation about a first spindle axis, at least one second work spindle mounted for rotation about a second spindle axis, and a workpiece clamping device configured to accommodate at least a first workpiece and a second workpiece, wherein the first work spindle and the second work spindle are arranged vertically one above the other. The method comprises the following method steps: Machining the first workpiece using the first work spindle; machining the second workpiece using the second work spindle.

[0024] The machining of the first workpiece and the machining of the second workpiece takes place simultaneously.

[0025] The method according to the invention has the advantage that long workpieces can be easily machined with high efficiency.

[0026] In particular, it may be advantageous if a change of the machining tool clamped in the first work spindle and a change of the machining tool clamped in the second work spindle take place simultaneously, wherein the machining tools are accommodated in a chain circulating magazine with several machining tool holders, wherein those machining tools which are arranged in those machining tool holders which correspond to the distance between the first work spindle and the second work spindle are of identical construction, wherein in a first method step the machining tool clamped in the first work spindle and the machining tool clamped in the second work spindle are each placed in a free machining tool holder of the chain circulating magazine and in a second method step the chain circulating magazine or the two work spindles are displaced,so that the first work spindle and the second work spindle are aligned with the newly mounted machining tools, and in a third process step, the newly mounted machining tools are mounted in the first work spindle and the second work spindle. This measure can shorten the setup time, further improving the efficiency of the machine tool.

[0027] Furthermore, it can be provided that a fourth workpiece is mounted on the fourth workpiece table and that a fifth workpiece is mounted on the fifth workpiece table, wherein the fourth work spindle is used to machine the fourth workpiece and wherein the fifth work spindle is used to machine the fifth workpiece, wherein the machining of the first workpiece, the machining of the second workpiece, the machining of the fourth workpiece, and the machining of the fifth workpiece take place simultaneously. This measure can further improve the efficiency of the machine tool while simultaneously keeping the complexity of the machine tool as low as possible.

[0028] Furthermore, it can be provided that the first workpiece, the second workpiece, the fourth workpiece, and the fifth workpiece are of identical design, with the machining of the first workpiece, the second workpiece, the fourth workpiece, and the fifth workpiece taking place in parallel, in work steps that are each executed simultaneously. This measure can further improve the efficiency of the machine tool, while at the same time keeping the control of the machine tool as simple as possible.

[0029] Furthermore, it can be provided that the first workpiece table, the second workpiece table, and optionally the third workpiece table are offset from one another in the direction of the Z-axis. This makes it possible to ensure that the individual workpiece tables are accessible from above, so that the machining tools can be lifted from the workpiece tables, for example, by means of a crane moving in from above. This measure can also ensure that chips from a machining tool of an upper work spindle cannot fall onto a machining tool of a lower work spindle, where they could disrupt the machining process.

[0030] Furthermore, it is conceivable that the first workpiece table, in particular the topmost workpiece table, is arranged at the farthest offset from the work head in the Z-axis direction. The second workpiece table can be further away from the work head in the Z-axis direction than the first workpiece table. The third workpiece table can be further away from the work head in the Z-axis direction than the second workpiece table.

[0031] It is conceivable that the individual work spindles are also offset from one another in the direction of the Z-axis. In particular, the offset of the individual work spindles in the direction of the Z-axis can be the same as the offset of the individual workpiece tables in the direction of the Z-axis. This allows the individual work spindles to be arranged on a common work head and to be moved together in the direction of the Z-axis using the common work head.

[0032] In a further design variant, it is also conceivable for the individual work spindles to be arranged in alignment one above the other, and for the individual workpiece tables to be individually and independently movable in the direction of the Z-axis. This allows the workpieces clamped on the workpiece tables to be arranged in alignment one above the other during machining. For workpiece changes, the individual workpiece tables can be offset from one another in the direction of the Z-axis.

[0033] Alternatively, it is also conceivable for the individual work spindles to be movable along the Z-axis, and for the individual workpiece tables to also be movable along the Z-axis. This allows the main travel movement along the Z-axis to be performed by the work spindles, and the movement of the individual workpiece tables along the Z-axis can be used for tolerance compensation.

[0034] A machining tool within the meaning of this document can, for example, be a cutting tool. A machining tool within the meaning of this document can also be, for example, a friction stir welding tool. In the broadest sense, a measuring or testing device mounted in the work spindle can also be considered a machining tool.

[0035] For a better understanding of the invention, it is explained in more detail with reference to the following figures.

[0036] They show in a highly simplified, schematic representation: Fig. 1 a perspective view of a first embodiment of a machine tool; Fig. 2 a side view of another embodiment of the machine tool with three work spindles; Fig. 3 a perspective view of another embodiment of the machine tool with a swivel bridge; Fig. 4 a perspective view of another embodiment of the machine tool with a chain circulating magazine; Fig. 5 a schematic representation of an embodiment of a machining system with two machine tools arranged next to one another; Fig. 6 a highly simplified representation of another embodiment of the machine tool with three workpiece tables arranged one above the other; Fig. 7 a highly simplified representation of another embodiment of the machine tool with three workpiece tables arranged one above the other and two rows of work spindles arranged next to one another; Fig.8 a highly simplified representation of a further embodiment of the machine tool with three workpiece tables arranged one above the other and further workpiece tables arranged next to them and two rows of work spindles arranged next to each other, each of which is assigned to a workpiece table; Fig. 9 a highly simplified representation of a further embodiment of the machine tool with three workpiece tables arranged one above the other on a swivel drum; Fig. 10 a highly simplified representation of a further embodiment of the machine tool with three workpiece tables arranged one above the other on a swivel drum and two rows of work spindles arranged next to each other; Fig. 11 a schematic side view of a further embodiment of the machine tool with four workpiece tables arranged one above the other and two work spindles arranged one above the other; Fig.12 a schematic side view of a further embodiment of the machine tool with two workpiece tables arranged one above the other and two workpieces arranged on each workpiece table; Fig. 13 a schematic side view of a further embodiment of the machine tool with two workpiece tables arranged one above the other and a rotary table arranged on the workpiece table for holding two workpieces each; Fig. 14 a highly simplified representation of a further embodiment of the machine tool with three workpiece tables arranged one above the other, wherein the individual workpiece tables are arranged offset from one another; Fig. 15 a highly simplified representation of a further embodiment of the machine tool with three workpiece tables arranged one above the other, wherein the individual workpiece tables are displaceable in the direction of the Z-axis.

[0037] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations, whereby the disclosures contained in the entire description can be applied mutatis mutandis to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and in the event of a change in position, these positional information must be applied mutatis mutandis to the new position.

[0038] Fig. 1 shows a schematic representation of a machine tool 1 for machining workpieces 32, 33. The machine tool 1 has a machine frame 2, which serves as a base for the components attached to it.

[0039] The machine frame 2 is in Fig. 1For the sake of clarity, it is shown only schematically. However, it should be noted that the machine frame 2 can be anchored at the installation site. Furthermore, the machine frame 2 naturally serves to accommodate all components of the machine tool 1.

[0040] Furthermore, a spindle adjustment device 3 is formed, which is arranged on the machine frame 2 or coupled thereto. The spindle adjustment device 3 has a work head 4, on which a first work spindle 5 and a second work spindle 6 are mounted. The first work spindle 5 is mounted on the work head 4 so as to be rotatable about a first spindle axis 7, and the second work spindle 6 is mounted on the work head 4 so as to be rotatable about a second spindle axis 8. The two work spindles 5, 6 each serve to hold a machining tool and, for this purpose, have a clamping device for holding the machining tool.

[0041] The work spindles 5, 6 are adjustable relative to the machine frame 2 by means of the spindle adjustment device 3 in a Z-axis 9, in an X-axis 10, and in a Y-axis 11 arranged at a right angle to the Z-axis 9 and X-axis 10. In particular, it can be provided that the Z-axis 9 is arranged horizontally. The Z-axis 9 is arranged parallel to the first spindle axis 7 and the second spindle axis 8. Furthermore, it can be provided that the X-axis 10 is also arranged horizontally. The X-axis 10 is arranged at a right angle to the Z-axis 9.

[0042] The spindle adjustment device 3 has a main adjustment unit 12, which is coupled to the machine frame 2 by means of an X-axis linear guide 13. For simplified illustration, the X-axis linear guide 13 is shown only rudimentarily. In particular, the X-axis linear guide 13 can be provided with four or more guide carriages, which are coupled to the main adjustment unit 12 and which interact with two guide rails that are coupled to the machine frame 2.

[0043] The X-axis linear guide 13 allows the main adjustment unit 12 to be displaced in the direction of the X-axis 10 relative to the machine frame 2.

[0044] Furthermore, it can be provided that a height adjustment unit 14 is formed, which is coupled to the main adjustment unit 12 by means of a Y-axis linear guide 15. The Y-axis linear guide 15 enables the height adjustment unit 14 to be displaced along the Y-axis 11 relative to the main adjustment unit 12 or relative to the machine frame 2.

[0045] In a first, in Fig. 1 In the embodiment shown, it can be provided that the first work spindle 5 and the second work spindle 6 are each arranged on their own height adjustment unit 14 and can thus be displaced independently of one another along a Y-axis 11. In this embodiment, a separate drive is required for each of the height adjustment units 14.

[0046] In another, in Fig. 2In the embodiment shown, it can be provided that the first work spindle 5 and the second work spindle 6 are arranged on a common height adjustment unit 14 and can thus be moved together along a Y-axis 11. In this embodiment, only a single drive is required for the common height adjustment units 14.

[0047] The Y-axis linear guide 15 may also comprise a guide rail which is arranged on the main adjustment unit 12 and which is coupled to one or more guide carriages which are arranged on the first work spindle 5 or the second work spindle 6.

[0048] Furthermore, as can be seen from the illustration Fig. 1As can be seen, it can be provided that the first work spindle 5 is displaceable in the Z-axis 9 by means of a first Z-axis linear guide 16 and that the second work spindle 6 is displaceable in the Z-axis 9 by means of a second Z-axis linear guide 16, wherein the first work spindle 5 and the second work spindle 6 are displaceable independently of one another.

[0049] In addition, the machine tool 1 comprises a workpiece clamping device 18, which serves to hold the workpieces 32, 33 to be machined.

[0050] The workpiece clamping device 18 has a first workpiece table 19 and a second workpiece table 20. The first workpiece table 19 is pivotable relative to the machine frame 2 with respect to a first pivot axis 21. The second workpiece table 20 is pivotable relative to the machine frame 2 with respect to a second pivot axis 22.

[0051] The two pivot axes 21, 22 of the two workpiece tables 19, 20 are arranged parallel to the X-axis 10. In particular, it is provided that the first workpiece table 19 serves to hold the first workpiece 32 and the second workpiece table 20 serves to hold the second workpiece 33.

[0052] In particular, it can be provided that the first workpiece 32 and the second workpiece 33 are formed identically to each other in their outer contour and the same processing steps are carried out on the two workpieces 32, 33. For the sake of clarity, the two workpiece tables 19, 20 are Fig. 1also only rudimentarily shown. Of course, a wide variety of fastening options can be provided for attaching the workpieces 32, 33 to the workpiece tables 19, 20. In particular, it can be provided that rotary tables are formed on each of the two workpiece tables 19, 20, which serve to fasten the workpieces 32, 33 and simultaneously to rotate the workpieces 32, 33 relative to the workpiece tables 19, 20.

[0053] The first workpiece table 19 is rotatably mounted on the machine frame 2 by means of a first pivot bearing 23 and a second pivot bearing 24. Similarly, the second workpiece table 20 is rotatably mounted on the machine frame 2 by means of a first pivot bearing 25 and a second pivot bearing 26. The pivot bearings 23, 24, 25, 26 can, for example, be designed in the form of bearing blocks, which are attached to corresponding receptacles on the workpiece table 19.

[0054] As from Fig. 1As can be seen, it can be provided that the first workpiece table 19 has a workpiece clamping area which extends between the first pivot bearing 23 and the second pivot bearing 24. Analogously, it can be provided that the second workpiece table 20 has a workpiece clamping area which extends between the first pivot bearing 25 and the second pivot bearing 26 of the second workpiece table 20.

[0055] The workpiece clamping area of ​​the first workpiece table 19 has a workpiece clamping length 27. The workpiece clamping area of ​​the second workpiece table 20 has a workpiece clamping length 28. Preferably, the first workpiece table 19 and the second workpiece table 20 are of identical design.

[0056] The two workpiece tables 19, 20 and the two pivot axes 21, 22 are arranged at a distance 29 from each other. The distance 29 also extends in the direction of the Y-axis 11. The described configuration ensures that the first work spindle 5 is assigned to the first workpiece table 19 and that the second work spindle 6 is assigned to the second workpiece table 20.

[0057] In particular, it can be provided that an adjusting device is arranged in the workpiece clamping device 18, by means of which the distance 29 between the two workpiece tables 19, 20 or the two pivot axes 21, 22 can be adjusted.

[0058] By means of the machine tool 1 according to the invention, two workpieces 32, 33 of identical construction can be machined parallel to one another. The first workpiece 32 is clamped to the first workpiece table 19 and the second workpiece 33 to the second workpiece table 20. The tool of the first work spindle 5 machines the first workpiece 32 and the tool of the second work spindle 6 machines the second workpiece 33. Due to the inventive design of the machine tool 1, the first workpiece 32 and the second workpiece 33 are machined synchronously. Thus, two workpieces 32, 33 can be machined simultaneously using a machine tool 1 with the simplest possible design, thereby improving the utilization of the machine tool 1 and its productivity.

[0059] Furthermore, it can be provided that the first workpiece table 19 has a drive unit for pivoting, and the second workpiece table 20 also has a drive unit 30 for pivoting. In such an embodiment, the first workpiece table 19 and the second workpiece table 20 can be pivoted independently of one another.

[0060] In an alternative variant, it can be provided that the workpiece tables 19, 20 are pivoted by means of a common drive unit 30.

[0061] The drive unit 30 can, for example, be designed in the form of a torque motor.

[0062] The torque motor can be coupled to the two workpiece tables 19, 20, for example, by means of a belt drive. Alternatively, the torque motor can be coupled to the two workpiece tables 19, 20 by means of a worm gear.

[0063] In yet another alternative variant, it can be provided that the rotor of the torque motor is integrated directly into the workpiece tables 19, 20 and thus a separate torque motor is formed for each workpiece table 19, 20.

[0064] Furthermore, it can be provided that the two work spindles 5, 6 are driven by a common drive unit 31. The drive unit 31 can, for example, be formed by a three-phase asynchronous motor controlled by a frequency converter.

[0065] Furthermore, it is also conceivable that the drive unit 31 is designed in the form of a synchronous motor.

[0066] Of course, it can also be provided that each of the work spindles 5, 6 is driven by its own drive unit 31. In this case, it can be provided that the work spindle 5, 6 is simultaneously the rotor of the drive unit 31.

[0067] The working spindles 5, 6 of the Fig. 1The machine tool 1 shown is displaceable relative to the Z-axis 9, the X-axis 10, and the Y-axis 11, and pivotable relative to a line parallel to the Y-axis. The workpieces 32, 33 held in the workpiece tables 19, 20 are pivotable relative to a line parallel to the X-axis 10. Thus, the work spindles 5, 6 have five degrees of freedom with respect to the adjustment relative to the workpiece 32, 33 being machined.

[0068] Furthermore, it can be provided that at least one of the work spindles 5, 6 is individually and independently of the other work spindle 5, 6 adjustable in an axial direction of the spindle axis 7, 8 of the work spindle 5, 6 relative to the work head 4. In a further development, it can be provided that both work spindles 5, 6 are adjustable in an axial direction of the spindle axis 7, 8 of the work spindle 5, 6 relative to the work head 4.

[0069] In the Fig. 2A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous Fig. 1 To avoid unnecessary repetition, please refer to the detailed description in the previous Fig. 1 In particular, it is pointed out that the embodiment of the machine tool 1 which is shown in Fig. 2 is shown, the same features or at least partially the same features as that embodiment of the machine tool 1 which is shown in Fig. 1 shown may have.

[0070] As from Fig. 2As can be seen, it can be provided that in addition to the first work spindle 5 and the second work spindle 6, a third work spindle 34 is formed, wherein the first work spindle 5, the second work spindle 6 and the third work spindle 34 are arranged vertically one above the other.

[0071] Regardless of the design of a third work spindle 34, it can be provided that a distance 35 between the first work spindle 5 and the second work spindle 6 is adjustable in the vertical Y-axis 11 by means of a spindle distance compensation device 36.

[0072] As from Fig. 2As can also be seen, it can be provided that a further X-axis linear guide 56 is formed, which is arranged at a distance from the X-axis linear guide 13. In particular, it can be provided that the X-axis linear guide 13 is arranged at a lower section of the height adjustment unit 14 and that the further X-axis linear guide 56 is arranged at an upper section of the height adjustment unit 14. As can be seen from Fig. 2 As can also be seen, it can be provided that the additional X-axis linear guide 56 is coupled to the workpiece clamping device. The measures described in this paragraph can further stabilize the height adjustment unit 14 and thus improve the accuracy of the machine tool 1.

[0073] As in Fig. 2As indicated schematically, it can be provided that a lifting support 57 is formed, which acts between the main adjustment unit 12 and one of the work spindles 5, 6, 34. By means of the lifting support 57, the weight of the work spindles 5, 6, 34 can be at least partially compensated, whereby the energy efficiency of the machine tool 1 can be improved. The lifting support 57 can, for example, be designed in the form of a pneumatic cylinder with a pressure accumulator. Furthermore, it is of course also conceivable that the lifting support 57 is designed, for example, in the form of a counterweight, which is coupled to the work spindle 5, 6, 34 by means of a traction means via a deflection. In particular, it can be provided that a separate lifting support 57 is formed for each of the work spindles 5, 6, 34.

[0074] In the Fig. 3A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 and 2. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 and 2 pointed out or referred to.

[0075] As from Fig. 3 As can be seen, the workpiece clamping device 18 can have a pivoting bridge 37, on which the first workpiece table 19 and the second workpiece table 20 are arranged on a first side 38. A first rear workpiece table 40 and a second rear workpiece table 41 are formed on a second side 39 of the pivoting bridge 37.

[0076] The first rear workpiece table 40 is pivotally mounted about a first rear pivot axis 42, which is aligned parallel to the horizontal X-axis 10.

[0077] The second rear workpiece table 41 is pivotally mounted about a second rear pivot axis 43, which is aligned parallel to the X-axis 10.

[0078] Furthermore, it is provided that the swivel bridge 37 is pivotally mounted about a swivel bridge axis 44 aligned parallel to the X-axis 10, so that depending on the swivel position of the swivel bridge 37 the first work spindle 5 is assigned to the first workpiece table 19 and the second work spindle 6 is assigned to the second workpiece table 20 or the first work spindle 5 is assigned to the first rear workpiece table 40 and the second work spindle 6 is assigned to the second rear workpiece table 41.

[0079] In other words, either the first side 38 of the swivel bridge 37 or the second side 39 of the swivel bridge 37 can be swiveled into the machining space of the machine tool 1.

[0080] As in Fig. 3 As indicated schematically, a partition wall 45 can be formed between the first side 38 of the pivot bridge 37 and the second side 39 of the pivot bridge 37. The partition wall 45 can be designed as a sheet metal construction.

[0081] In particular, it can be provided that the swivel bridge 37 is accommodated in the machine tool 1 in such a way that the partition wall 45, together with a housing of the machine tool 1, closes off the machining space of the machine tool so that it is not accessible from the outside.

[0082] In the Fig. 4A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 3. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 3 pointed out or referred to.

[0083] As from Fig. 4As can be seen, a tool magazine 47 can be arranged at a longitudinal end 46 of the workpiece clamping device 18. The tool magazine 47 comprises a chain-type magazine 48, wherein a straight run 49 of the chain-type magazine 48 is aligned vertically. The first work spindle 5 and the second work spindle 6 can be moved up to the straight run 49 of the chain-type magazine 48. The machining tools 50 can thus be removed from the chain-type magazine 48 or placed in it directly by means of the first work spindle 5 or the second work spindle 6.

[0084] In particular, it can be provided that the distance 35 between the first work spindle 5 and the second work spindle 6 corresponds to a pitch 51 or a multiple of the pitch 51 of the chain circulating magazine 48. The pitch 51 refers to the distance between the individual machining tool holders 52 of the chain circulating magazine 48.

[0085] In the Fig. 5 A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 4. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 4 pointed out or referred to.

[0086] As from Fig. 5 As can be seen, it can be provided that a machining system 53 is formed in which at least two of the machine tools 1 are arranged next to one another. In particular, it can be provided that a common control system 54 and / or a common media supply 55 is formed for both machine tools 1.

[0087] In the embodiment according to Fig. 5 the two machine tools 1 are mirrored.

[0088] In the Fig. 6 A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 5. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 5 referred to or referred to. The machine tool 1 is in Fig. 6 presented in a very simplified manner for the sake of clarity.

[0089] As from Fig. 6 As can be seen, the machine tool 1 can have the third work spindle 34 below the first work spindle 5 and the second work spindle 6. The work spindles 5, 6, 34 can be arranged one above the other. Fig. 6As can also be seen, it can be provided that the first work spindle 5 is assigned to the first workpiece table 19 and serves to machine the first workpiece 32 mounted thereon. The second work spindle 6 can be assigned to the second workpiece table 20 and serve to machine the second workpiece 33 mounted thereon. The third work spindle 34 can be assigned to a third workpiece table 61 and serve to machine the third workpiece 67 mounted thereon. The individual work spindles 5, 6, 34 can be displaceable individually and independently of one another. Alternatively, it is also conceivable for the individual work spindles 5, 6, 34 to be mounted on a common work head 4 and to be displaceable together.

[0090] In the Fig. 7A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 6. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 6 pointed out or referred to.

[0091] As from Fig. 7As can be seen, it can be provided that a fourth work spindle 58 is arranged next to the first work spindle 5, which can be assigned to the first workpiece table 19. Furthermore, a fifth work spindle 59 can be formed next to the second work spindle 6, which can be assigned to the second workpiece table 20. Furthermore, a sixth work spindle 60 can be formed next to the third work spindle 34, which can be assigned to the third workpiece table 61. The fourth work spindle 58 can be used to machine a fourth workpiece 68. The fifth work spindle 59 can be used to machine a fifth workpiece 69. The sixth work spindle 60 can be used to machine a sixth workpiece 70.

[0092] As from Fig. 7As can also be seen, the work magazine 47 can be arranged at one of the longitudinal ends 46 of the workpiece clamping device 18. A further tool magazine 66 can be arranged at the second longitudinal end 65 of the workpiece clamping device 18.

[0093] In the Fig. 8 A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 7. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 7 pointed out or referred to.

[0094] As from Fig. 8As can be seen, it can be provided that the first work spindle 5 is assigned to the first workpiece table 19 and serves to machine the first workpiece 32 mounted thereon. The second work spindle 6 can be assigned to the second workpiece table 20 and serve to machine the second workpiece 33 mounted thereon. The third work spindle 34 can be assigned to a third workpiece table 61 and serve to machine the third workpiece 67 mounted thereon.

[0095] As from Fig. 8As can also be seen, it can be provided that a fourth workpiece table 62 is formed next to the first workpiece table 19. Furthermore, it can be provided that a fifth workpiece table 63 is arranged next to the second workpiece table 20. Furthermore, it can be provided that a sixth workpiece table 64 is arranged next to the third workpiece table 61. The fourth work spindle 58 can be assigned to the fourth workpiece table 62, the fifth work spindle 59 can be assigned to the fifth workpiece table 63, and the sixth work spindle 60 can be assigned to the sixth workpiece table 64.

[0096] In particular, it can be provided that the first workpiece table 19, the second workpiece table 20, the third workpiece table 61, the fourth workpiece table 62, the fifth workpiece table 63 and the sixth workpiece table 64 are accommodated on a common machine frame 2.

[0097] In an embodiment of the machine tool 1 as shown in Fig. 8 As shown, it can be provided that a first longitudinal end of the first workpiece 32 is received on the first workpiece table 19 and that a second longitudinal end of the first workpiece 32 is received on the fourth workpiece table 62. This has the advantage that longer workpieces can be clamped on the machine tool 1 as a result of this measure. The first longitudinal end of the first workpiece 32 is machined by means of the first work spindle 5 and the second longitudinal end of the first workpiece 32 is machined by means of the fourth work spindle 58. In such an embodiment, a rotational movement of the first workpiece table 19 and a rotational movement of the fourth workpiece table 62 must be synchronized.

[0098] In particular, it is conceivable that a possible machining area of ​​the first work spindle 5 and a possible machining area of ​​the fourth work spindle 58 overlap, so that it can be achieved that the first workpiece 32 can be machined over its full length.

[0099] Of course, the second workpiece table 20 and the fifth workpiece table 63 can be used analogously to jointly hold the second workpiece 33.

[0100] Furthermore, the third workpiece table 61 and the sixth workpiece table 64 can serve analogously to jointly hold the third workpiece 67.

[0101] In the Fig. 9A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 8. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 8 pointed out or referred to.

[0102] As from Fig.9 As can be seen, it can be provided that the first workpiece table 19, the second workpiece table 20, and the third workpiece table 61 are arranged on the first side 38 of the pivoting bridge 37. The first rear workpiece table 40, the second rear workpiece table 41, and the third rear workpiece table 71 can be arranged on the second side 39 of the pivoting bridge 37.

[0103] As from Fig. 9As can also be seen, it can be provided that the first work spindle 5 is assigned to the first workpiece table 19 or the first rear workpiece table 40. Furthermore, it can be provided that the second work spindle 6 is assigned to the second workpiece table 20 or the second rear workpiece table 41. Furthermore, it can be provided that the third work spindle 34 is assigned to the third workpiece table 61 or the third rear workpiece table 71.

[0104] In the Fig. 10 A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 9. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 9 pointed out or referred to.

[0105] As from Fig. 10 As can be seen, it can be provided that the first workpiece table 19, the second workpiece table 20, and the third workpiece table 61 are arranged on the first side 38 of the pivoting bridge 37. The first rear workpiece table 40, the second rear workpiece table 41, and the third rear workpiece table 71 can be arranged on the second side 39 of the pivoting bridge 37.

[0106] As from Fig. 10 As can also be seen, it can be provided that the first work spindle 5 is assigned to the first workpiece table 19 or the first rear workpiece table 40. Furthermore, it can be provided that the second work spindle 6 is assigned to the second workpiece table 20 or the second rear workpiece table 41. Furthermore, it can be provided that the third work spindle 34 is assigned to the third workpiece table 61 or the third rear workpiece table 71.

[0107] As from Fig. 10As can also be seen, a fourth work spindle 58 can be arranged next to the first work spindle 5, which can be assigned to the first workpiece table 19 or the first rear workpiece table 40. Furthermore, a fifth work spindle 59 can be formed next to the second work spindle 6, which can be assigned to the second workpiece table 20 or the second rear workpiece table 41. Furthermore, a sixth work spindle 60 can be formed next to the third work spindle 34, which can be assigned to the third workpiece table 61 or the third rear workpiece table 71. The fourth work spindle 58 can be used to machine a fourth workpiece 68. The fifth work spindle 59 can be used to machine a fifth workpiece 69. The sixth work spindle 60 can be used to machine a sixth workpiece 70.

[0108] In the examples according to the Figures 6 to 10Of course, the third work spindle 34, the third workpiece table 61, the sixth work spindle 60, the sixth workpiece table 64 or the third rear workpiece table 71 can also be omitted, so that only two work spindles or workpiece tables are arranged one above the other.

[0109] In the Fig. 11 A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 10. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 10 pointed out or referred to.

[0110] In Fig. 11 the machine tool 1 is shown in a side view.

[0111] As from Fig. 11As can be seen, it can be provided that the first work spindle 5 is designed to machine a workpiece clamped on the first workpiece table 19 and, at a different time, to machine a workpiece clamped on the second workpiece table 20.

[0112] The second work spindle 6 can be configured to machine a workpiece clamped on the third workpiece table 61 and, at a different time, to machine a workpiece machined on the fourth workpiece table 62. In this embodiment, too, the individual workpiece tables can be arranged one above the other.

[0113] In the Fig. 12A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 11. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 11 pointed out or referred to.

[0114] In Fig. 12 the machine tool 1 is shown in a side view.

[0115] As from Fig. 12As can be seen, it can be provided that a first workpiece 32 and a second workpiece 33 are held vertically one above the other on the first workpiece table 19. The first work spindle 5 can be used for the staggered machining of the first workpiece 32 held on the first workpiece table 19 and the second workpiece 33 held on the first workpiece table 19. The second work spindle 6 can be used for the staggered machining of the third workpiece 67 held on the second workpiece table 20 and the fourth workpiece 68 held on the second workpiece table 20.

[0116] In the Fig. 13A further and possibly independent embodiment of the machine tool 1 is shown in a schematic representation, wherein the same reference numerals or component designations are used for the same parts as in the previous figures 1 to 12. To avoid unnecessary repetition, reference is made to the detailed description in the previous Figures 1 to 12 pointed out or referred to.

[0117] In Fig. 13 the machine tool 1 is shown in a side view.

[0118] As from Fig. 13 As can be seen, it can be provided that a first rotary table 72, which has a pivot axis 73, is received on the first workpiece table 19. The first workpiece 32 and the second workpiece 33 can be received on the first rotary table 72, offset in the axial direction with respect to the first pivot axis 73.

[0119] Furthermore, it can be provided that a second rotary table 74, which has a second pivot axis 75, is mounted on the second workpiece table 20. The third workpiece 67 and the fourth workpiece 68 can be mounted on the second rotary table 74, offset in the axial direction with respect to the second pivot axis 75.

[0120] Of course, it's also conceivable for multiple workpieces to be arranged on one rotary table. Furthermore, it's also conceivable for multiple rotary tables to be arranged one above the other.

[0121] In the Fig. 14 A schematic representation of a further and possibly independent embodiment of the machine tool 1 is shown in a side view, wherein again the same reference numerals or component designations are used for the same parts as in the previous Figures 1 to 13 To avoid unnecessary repetition, please refer to the detailed description in the previous Figures 1 to 13pointed out or referred to.

[0122] As from Fig. 14 As can be seen, it can be provided that the first workpiece table 19, in particular the uppermost workpiece table 19, is arranged offset furthest from the work head 4 in the direction of the Z-axis 9. The second workpiece table 20 can be spaced further from the work head in the direction of the Z-axis 9 than the first workpiece table 19. The third workpiece table 61 can be spaced further from the work head 4 in the direction of the Z-axis 9 than the second workpiece table 20.

[0123] In the Fig. 15 A schematic representation of a further and possibly independent embodiment of the machine tool 1 is shown in a side view, wherein again the same reference numerals or component designations are used for the same parts as in the previous Figures 1 to 14To avoid unnecessary repetition, please refer to the detailed description in the previous Figures 1 to 14 pointed out or referred to.

[0124] As from Fig. 15 As can be seen, it can be provided that the individual workpiece tables 19, 20, 61 are displaceable in the direction of the Z-axis 9.

[0125] The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with one another are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0126] The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying the independent inventive solutions can be derived from the description.

[0127] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0128] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size. Reference symbol list 1 machine tool 26 second swivel bearing second workpiece table 2 Machine frame 3 common spindle adjustment device 27 Workpiece clamping length Workpiece clamping area first workpiece table 4 Working head 5 first work spindle 28 Workpiece clamping length Workpiece clamping range second workpiece table 6 second work spindle 7 first spindle axis 8 second spindle axis 29 Distance between workpiece tables 9 Z-axis 30 Drive unit workpiece tables 10 X-axis 31 Drive unit work spindles 11 Y-axis 32 first workpiece 12 Main adjustment unit 33 second workpiece 13 X-axis linear guide 34 third work spindle 14 Height adjustment unit 35 Distance between first work spindle and second work spindle 15 Y-axis linear guide 16 Z-axis linear guide 36 Spindle distance compensation device 17 Swivel bearing working head 18 Workpiece clamping device 37 Swing bridge 19 first workpiece table 38 first side of the swing bridge 20 second workpiece table 39 second side of the swing bridge 21 first swivel axis 40 first rear workpiece table 22 second swivel axis 41 second rear workpiece table 23 first swivel bearing first workpiece table 42 first rear swivel axis 24 second swivel bearing first workpiece table 43 second rear swivel axis 44 Swing bridge axle 25 first swivel bearing second workpiece table 45 partition 46 Longitudinal end 47 tool magazine 48 Chain circulating magazine 49 straight run 50 Editing tool 51 division 52 Machining tool holder 53 processing plant 54 Control technology 55 Media supply 56 additional X-axis linear guide 57 Lifting support 58 fourth work spindle 59 fifth work spindle 60 sixth work spindle 61 third workpiece table 62 fourth workpiece table 63 fifth workpiece table 64 sixth workpiece table 65 second longitudinal end 66 additional tool magazine 67 third workpiece 68 fourth workpiece 69 fifth workpiece 70 sixth workpiece 71 third rear workpiece table 72 first round table 73 Swivel axis of the first rotary table 74 second round table 75 Swivel axis of second rotary table

Claims

1. A machine tool (1) comprising: a machine frame (2); at least one first working spindle (5) which is pivotable about a first spindle axis (7); at least one second working spindle (6) which is pivotable about a second spindle axis (8); a workpiece clamping device (18) which is configured to receive at least a first workpiece (32) and a second workpiece (33), wherein the first working spindle (5) and the second working spindle (6) are arranged vertically above one another, wherein the workpiece clamping device (18) comprises at least a first workpiece table (19) and a second workpiece table (20), wherein the first working spindle (5) is assigned to the first workpiece table (19) and the second working spindle (6) is assigned to the second workpiece table (20), wherein the first workpiece table (19) is pivotable about a first pivot axis (21), which is aligned parallel to a horizontal X-axis (10), and the second workpiece table (20) is pivotable about a second pivot axis (22), which is aligned parallel to the X-axis (10), wherein a spindle adjusting device (3) is formed, which is arranged on the machine frame (2) and / or coupled thereto, wherein the spindle adjusting device (3) has a main adjusting unit (12), which is coupled to the machine frame (2) by means of an X-axis linear guide (13), wherein the main adjusting unit (12) is displaceable in the direction of the X-axis (10) relative to the machine frame (2) by means of the X-axis linear guide (13), wherein the X-axis linear guide (13) has four or more guide carriages which are coupled to the main adjusting unit (12) and which interact with two guide rails which are coupled to the machine frame (2), wherein a height adjusting unit (14) is formed, which is coupled to the main adjusting unit (12) by means of a Y-axis linear guide (15), wherein the height adjusting unit (14) is displaceable along the Y-axis (11) relative to the main adjusting unit (12) or relative to the machine frame (2) by means of the Y-axis linear guide (15), wherein the first working spindle (5) and the second working spindle (6) are each arranged on a separate height adjusting unit (14) and are thus displaceable independently of one another along a Y-axis (11), wherein a separate drive is provided for each of the height adjusting units (14), wherein the first working spindle (5) is displaceable in the Z-axis (9) by means of a first Z-axis linear guide (16) and wherein the second working spindle (6) is displaceable in the Z-axis (9) by means of a second Z-axis linear guide (16), wherein the first working spindle (5) and the second working spindle (6) are displaceable independently of one another.

2. The machine tool (1) according to claim 1, characterized in that a tool magazine (47) is arranged at a longitudinal end (46) of the workpiece clamping device (18), wherein the tool magazine (47) comprises a chain circulation magazine (48), wherein a straight run (49) of the chain circulation magazine (48) is aligned vertically, wherein the first working spindle (5) and the second working spindle (6) can be displaced to the straight run (49) of the chain circulation magazine (48), wherein a distance (35) between the first working spindle (5) and the second working spindle (6) corresponds to a pitch (51) or a multiple of the pitch (51) of the chain circulation magazine (48).

3. The machine tool (1) according to claim 1, characterized in that rotary tables (72, 73) are formed on each of the two workpiece tables (19, 20), which rotary tables (72, 73) serve to fasten the workpieces (32, 33) and at the same time to rotate the workpieces (32, 33) relative to the workpiece tables (19, 20).

4. The machine tool (1) according to claim 1, characterized in that the first workpiece table (19) is rotatably mounted on the machine frame (2) by means of a pivot bearing (23) and a pivot bearing (24) and the second workpiece table (20) is rotatably mounted on the machine frame (2) by means of a pivot bearing (25) and a pivot bearing (26).

5. A method for operating a machine tool (1) having a machine frame (2), a first working spindle (5) which is pivotable about a first spindle axis (7), at least one second working spindle (6) which is pivotable about a second spindle axis (8), and a workpiece clamping device (18) which is configured to receive at least a first workpiece (32) and a second workpiece (33), wherein the first working spindle (5) and the second working spindle (6) are arranged vertically one above the other, comprising the method steps: - processing the first workpiece (32) by means of the first working spindle (5); - processing the second workpiece (33) by means of the second working spindle (6), wherein the processing of the first workpiece (32) and the processing of the second workpiece (33) are performed simultaneously, wherein the workpiece clamping device (18) comprises at least a first workpiece table (19) and a second workpiece table (20), wherein the first working spindle (5) is assigned to the first workpiece table (19) and the second working spindle (6) is assigned to the second workpiece table (20), wherein the first workpiece table (19) is pivotable about a first pivot axis (21), which is aligned parallel to a horizontal X-axis (10), and the second workpiece table (20) is pivotable about a second pivot axis (22), which is aligned parallel to the X-axis (10), wherein a spindle adjusting device (3) is formed, which is arranged on the machine frame (2) and / or coupled thereto, wherein the spindle adjusting device (3) has a main adjusting unit (12), which is coupled to the machine frame (2) by means of an X-axis linear guide (13), wherein the main adjusting unit (12) is displaceable in the direction of the X-axis (10) relative to the machine frame (2) by means of the X-axis linear guide (13), wherein the X-axis linear guide (13) has four or more guide carriages which are coupled to the main adjusting unit (12) and which interact with two guide rails which are coupled to the machine frame (2), wherein a height adjusting unit (14) is formed, which is coupled to the main adjusting unit (12) by means of a Y-axis linear guide (15), wherein the height adjusting unit (14) is displaceable along the Y-axis (11) relative to the main adjusting unit (12) or relative to the machine frame (2) by means of the Y-axis linear guide (15), wherein - the first working spindle (5) and the second working spindle (6) are arranged on a common height adjusting unit (14) and are thus jointly displaceable along a Y-axis (11), wherein only a single drive is provided for the common height adjusting unit (14), or - the first working spindle (5) and the second working spindle (6) are each arranged on a separate height adjusting unit (14) and are thus displaceable independently of one another along a Y-axis (11), wherein a separate drive is provided for each of the height adjusting units (14), wherein the first working spindle (5) is displaceable in the Z-axis (9) by means of a first Z-axis linear guide (16) and wherein the second working spindle (6) is displaceable in the Z-axis (9) by means of a second Z-axis linear guide (16), wherein the first working spindle (5) and the second working spindle (6) are displaceable independently of one another.

6. The method according to Claim 5, characterized in that a change of the machining tool (50) clamped in the first working spindle (5) and a change of the machining tool (50) clamped in the second working spindle (6) is performed simultaneously, wherein the machining tools (50) are received in a chain circulation magazine (48) with multiple machining tool receptacles (52), wherein those machining tools (50) arranged in those machining tool receptacles (52) which correspond to the distance (35) between the first working spindle (5) and the second working spindle (6) are configured structurally identically, wherein in a first method step the machining tool (50) clamped in the first working spindle (5) and the machining tool (50) clamped in the second working spindle (6) are each deposited in a vacant machining tool receptacle (52) of the chain circulation magazine (48) and in a second method step the chain circulation magazine (48) or the two working spindles (5, 6) are displaced so that the first working spindle (5) and the second working spindle (6) are aligned with the machining tools (50) to be newly received and wherein in a third method step the machining tools (50) to be newly received are received in the first working spindle (5) and in the second working spindle (6).