WO2003084712A2

WO2003084712A2 - Machine-tool comprising a tool spindle which can be displaced on an arc

Info

Publication number: WO2003084712A2
Application number: PCT/CH2003/000213
Authority: WO
Inventors: Walter MÖRI-FREY
Original assignee: Spacemill Ag
Priority date: 2002-04-05
Filing date: 2003-04-02
Publication date: 2003-10-16
Also published as: AU2003212179A1; DE10215195A1; WO2003084712A3; AU2003212179A8

Abstract

The invention relates to a machine-tool (10), especially a universal milling machine, comprising a table (12) for fixing a workpiece to be machined in a horizontal machining plane, and a tool spindle (65) which is arranged in a pivoting plane perpendicular to the machining plane in such a way that it can be continuously pivoted between a vertical position and a horizontal position, on an orbit which goes around the table (12) which forms the centre. The tool spindle (65) is fixed to an arc segment (15) which can be guided on an arc in a first arc guide (14) in a displaceable manner. The aim of the invention is to create one such machine-tool (10) with a compact structure, simultaneously reducing the production and assembly means, and improving the accessibility to the working chamber. To this end, the first arc guide (14) has the form of a circular arc section surrounding the table (12) only on one side.

Description

DESCRIPTION

MACHINE TOOL, ESPECIALLY UNIVERSAL MILLING MACHINE, AND METHOD FOR OPERATING SUCH A MACHINE

TECHNICAL AREA

The present invention relates to the field of machine tools. It relates to a machine tool, in particular a universal milling machine according to the preamble of claim 1.

Such a machine tool is e.g. known from US-A-1, 991, 285.

STATE OF THE ART

In the past, various universal machine tools or universal milling machines have been proposed in which the one to be machined Workpiece is held on a horizontal table which can be moved horizontally in a longitudinal direction and a tool or work spindle can be pivoted in a plane perpendicular to the longitudinal direction on an arcuate path around the table with the workpiece. The table with the workpiece is located in the center of the circular arc and the tool spindle is mounted so that the spindle axis is aligned vertically, horizontally or with an intermediate angle, depending on the swivel angle. The tool spindle is mounted in a corresponding arc guide so that the machining area is freely available in the center of the circular arc.

An early example of such a machine tool is described in the aforementioned US Pat. No. 1,991,285. The tool spindle is mounted there on a cross slide unit, the base of which forms an arc segment. The arch segment is slidably mounted on a vertical arch guide that almost completely encloses the work table at an angle of approximately 270 °. Not only is the one-sided weight distribution unfavorable with this arrangement, but also the problem that a motor drive for pivoting the tool spindle cannot be arranged in a stationary manner on the frame of the machine.

Another solution was therefore later proposed (US-A-2,042,720), in which the tool spindle, including the cross slide, is fastened to a guide element in the form of a closed circular ring, which in turn is rotatably mounted on the outside of a circular housing. In this configuration, a stationary drive can be used via a combination of pinion and ring gear. Furthermore, balancing weights can be provided on the guide element on the side opposite the tool spindle.

A comparable solution is disclosed in DE-OS-2 255 540. Here, the work spindle with its cross slide unit is attached to a closed circular metal ring, which is in a circular bearing recess in the vertical Frame of the machine is rotatably mounted. Here too, a stationary drive of the ring is provided via a combination of pinion and ring gear and a counterweight on the opposite side. It is also proposed that that generated by the tool spindle. Compensate for unbalance torque by means of a second pinion driven by a motor, which engages in the ring gear.

Although the latter two solutions have advantages over the configuration from US-A-1, 991, 285 with regard to the drive and the weight distribution, the curved guide, which is designed as a closed circle, not only results in a considerable expenditure of material and processing and assembly time, but also increases the outside dimensions of the machine and limits the space of the additional devices such as an automatic tool changer is available. In addition, access to the machining area of the machine in the area of the table is generally restricted.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a flexible and universally usable machine tool with a continuously swiveling tool spindle, which avoids the disadvantages of known machines and is characterized in particular by a space-saving design and a significantly reduced material and manufacturing outlay, is easily accessible from the outside and a lot Space for additional equipment such as provides an automatic tool changer, as well as a procedure for their operation.

The object is achieved by the entirety of the features of claims 1 and 20. The essence of the invention is that the first arc guide is limited to a circular arc section open to one side. As a result, the cost of material and manufacturing and assembly costs is significantly reduced without significantly restricting the processing options, and the space needs the machine reduced and at the same time created space for additional equipment on the machine such as an automatic tool changer. The first curved guide preferably has approximately the shape of a semicircle, and the curved segment has a segment angle of approximately 90 °.

A preferred embodiment of the machine tool according to the invention is characterized in that a drive for moving the tool spindle is arranged on the first curved guide, which drive meshes with a round rack attached to the curved segment via a first pinion. As a result, an additional weight load on the movable unit consisting of tool spindle and arc segment by the drive unit can be avoided.

To increase the positioning accuracy, it is advantageous if, according to another embodiment, the drive comprises a first motor, which drives a drive shaft via a worm gear, if the drive shaft is toothed with the first pinion, if the drive shaft is helically toothed with the first pinion, and the helical gearing is axially adjustable to cancel the play, and if, in addition to the first tooth pinion, a second mechanically coupled and braced tooth pinion is arranged to eliminate the tooth play, which meshes with the round rack.

Furthermore, it is advantageous for the accuracy if a second motor is fixedly arranged on the first sheet guide, which drives a third pinion via a gear, which third pinion meshes with the round rack and the round rack with a torque to compensate for the weight of the arc segment and the tool spindle. Instead of the motor, the weight can also be relieved by a spiral spring system acting on the pinion.

In order to gain additional degrees of freedom when machining the workpieces spanned on the table, it is advantageous if a cross slide unit is arranged between the tool spindle and the arc segment, and for Adjustment of the cross slide unit in the two orthogonal axes, two linear drives each equipped with a motor and a spindle are provided.

A particularly simple and, in terms of functionality, favorable construction of the machine is obtained if the machine tool has an elongated machine bed on which the table is arranged, if a stand unit is attached to the machine bed on one long side, in particular screwed on, which extends upwards over the machining plane protrudes, and when the first sheet guide is arranged on a side of the stand unit which is transverse to the longitudinal direction of the machine bed. The table can preferably be designed as a longitudinal table which can be moved in the longitudinal direction on the machine bed.

According to another preferred embodiment of the invention, the tool spindle is a milling spindle, and the milling spindle is integrated in a milling bar and is moved together with the milling bar.

The advantages of the compact construction of the machine tool according to the invention become particularly apparent when an automatic tool changer is provided on the machine tool. Due to the semicircular design of the curved guide, the open side of the semicircle is available as a space for the tool changer. The tool changer preferably comprises a tool magazine and an exchange unit, which exchange unit transports tools between the tool magazine and the tool spindle. In particular, the tools are held in the tool magazine with a first, predetermined orientation, and the exchange unit has means with which the tools can be pivoted from the first orientation into a second orientation during transport from the tool magazine to the tool spindle, which corresponds to the respective orientation of the Tool spindle corresponds when changing the tool, or can be pivoted from the second to the first orientation during transport from the tool spindle to the tool magazine. According to an advantageous development, the exchange unit can be moved perpendicular to the pivoting plane of the tool spindle between the tool magazine and the tool spindle, and the pivoting means are designed in such a way that the tool can be pivoted in a plane parallel to the pivoting plane of the tool spindle. The pivot means preferably include a second sheet guide in which a rotating unit with grippers for the tools is guided on a sheet. Here too, a drive provided with a motor can be provided for moving the rotary unit, in which a pinion meshes with a round rack.

A preferred embodiment of the method according to the invention is characterized in that the tool changer comprises a tool magazine in which the tools are held with a first, predetermined orientation, and in that the tool changer transports the tools from the tool magazine to the tool spindle from the first orientation pivoted into a second orientation, which corresponds to the respective orientation of the tool spindle when changing the tool, or swivels back from the second orientation into the first orientation during transport from the tool spindle to the tool magazine.

Further embodiments result from the dependent claims.

BRIEF EXPLANATION OF THE FIGURES

The invention will be explained in more detail below on the basis of exemplary embodiments in connection with the drawing. Show it

Fig. 1 in different partial figures, different views of a preferred embodiment of a machine tool according to the Invention, wherein FIG. 1A shows the plan view in the direction of the machine longitudinal axis from the direction of the tool magazine, FIG. 1C shows the plan view in the direction of the machine longitudinal axis from the opposite direction, and FIGS. 1B and D show two different perspective side views;

FIG. 2 shows an enlarged view of a section of the machine according to FIG. 1 with the drive for moving the tool spindle and the tool spindle with the cross slide unit;

3 shows a simplified illustration of the internal structure of the drive for moving the tool spindle;

4 shows a longitudinal section through the drive for the movement of the tool spindle;

5 taken alone the exchange unit of the tool changer of the machine tool according to FIG. 1 in plan view in the direction of the machine longitudinal axis;

6 shows a perspective side view of the exchange unit according to FIG.

5;

7 shows a perspective side view of the arrangement of the exchange unit on the machine, with essential parts of the machine being omitted;

8 shows a snapshot of a tool change process with the tool spindle standing vertically;

9 shows a snapshot of a tool change process with the tool spindle at an angle; and 10 shows a snapshot of a tool change process with the tool spindle lying horizontally.

WAYS OF CARRYING OUT THE INVENTION

1 shows different views of a preferred exemplary embodiment of a machine tool according to the invention in different partial figures. 1A shows the top view in the direction of the machine longitudinal axis from the direction of the tool magazine, FIG. 1C shows the top view in the direction of the machine longitudinal axis from the opposite direction. 1B and 1D show two different perspective side views. The machine tool 10, which is preferably designed as a universal milling machine, comprises a stable, elongated machine bed 11, on which a longitudinal table 12 is arranged so as to be movable in the longitudinal direction. The longitudinal table 12 can be a rigid table. However, it is also conceivable to provide a (rotatable) rotary table 67, as indicated in FIGS. 1B and 1D.

The longitudinal table 12 is mounted according to FIG. 9 on a slide 63 which can be moved in the direction of the machine longitudinal axis by means of roller shoes 64 on two parallel guides 54, 55. A linear drive with a spindle 61 is provided for driving the carriage 63. The longitudinal table 12 is designed in the usual way for clamping workpieces to be machined. A vertical rectangular flange (62 in FIG. 7) is provided on the machine bed 11, on which a stand unit 13, which extends laterally outwards and upwards beyond the working plane of the longitudinal table 12, is screwed. The stand unit 13 carries (in the case of the universal milling machine) a movable milling bar 17 in which the actual tool spindle 65 (FIG. 1 D) is accommodated. The milling bar 17 is mounted on a cross slide unit 16 and by means of two linear drives, which according to FIG. 2 each comprise a motor 27, 30 (with gear) and a spindle 29, 31, in two orthogonal ones Movable axes. The cross slide unit 16 is in turn mounted on an arc segment 15 which has a segment angle of approximately 90 °. The arc segment 15 is movably supported in an arc guide 14 on a circular arc, which lies in a pivot plane oriented perpendicular to the longitudinal axis of the machine and has the longitudinal table 12 as the center. The curved guide 14, which is arranged on a side of the stand unit 13 oriented perpendicular to the longitudinal axis of the machine, has the shape of a semicircle of approximately 180 ° and is open to the side of the machine bed 11 opposite the stand unit 13.

The arch guide 14 has two arch-shaped guides 35, 36 (FIG. 4) separated by a space on which the arch segment 15 runs. The arch segment 15 is secured to the arch guide 4 by a retaining strip 37 which engages behind the lower guide 36 (FIG. 4). Behind the upper guide 35, a round toothed rack 21 (see also FIG. 2), which is screwed onto the curved segment 15, also serves to drive the curved segment 15. According to FIGS. 2 to 4, the arc segment 15 is driven via a drive unit 22 which is arranged in a fixed manner on the arc guide 14 and which comprises a motor 24 which drives a first pinion (main pinion) 32 via a worm gear 25, which pinion (main gear) 32 21 combs. A drive shaft 66 coming from the worm gear 25 is helically toothed in a gear 23 with the first toothed pinion 32, the helical toothing being axially adjustable to eliminate play.

To increase the positioning accuracy, a second pinion 33 is arranged in the gear 23 according to FIG. 3, which is mechanically coupled and clamped to eliminate the tooth play and also meshes with the round tooth length 21. Because of this, a two-motor 26, which drives a third pinion 34 via a gear 38, is arranged in a stationary manner on the first curved guide 14 according to FIGS. 2 and 3. The third cog 34 also meshes with the round rack 21 and applies a torque to the round rack 21, with which the weight of the arc segment 15 and the tool spindle 65 comes into play. can be penalized. Instead of the motor 26, another power source, such as a coil spring system, can also be used as the power source.

The machine tool according to FIG. 1 additionally has an automatic tool changer 18 which is arranged at one end of the machine bed 11. The tool changer 18 comprises a tool magazine 19 lying horizontally above the machining plane, in which a plurality of tools 59 are held hanging vertically downwards and can be transported past a removal point on a closed oval path at which a lifting device 60 is provided. An exchange unit 20, which is shown in more detail in FIGS. 5 and 6, is provided for transporting the tools 59 between the tool magazine 19 and the tool spindle 65 accommodated in the milling beam 17. The exchange unit 20 is constructed on a slide 39 which can be moved in the longitudinal direction of the machine by means of roller shoes 57, 58 on the same guides 54, 55 as the longitudinal table 12. A linear drive is provided for the movement of the slide 39, which comprises a motor 41 fastened to a holding plate 40 with a flange-mounted gear and a spindle 42.

An upwardly extending arc 51 is fastened on the slide 39 in a plane lying parallel to the pivoting plane of the tool spindle 65. The arc carries an arc guide 53 and a round rack 52 side by side on the one side. In the arc guide 53, a rotating unit 43 is movably supported on a circular arc by means of a bearing plate 50 and roller shoes 56. A motor 49 is provided for the drive, which drives a toothed pinion which meshes with the round toothed rack 52. The rotating unit 43 has a support arm 44 standing vertically in the basic position shown in FIGS. 5, 6, at the upper end of which two opposite, horizontal grippers 45, 46 are arranged so as to be rotatable about a vertical axis. The grippers 45, 46 can be rotated through 180 ° about the vertical axis by means of two hydraulic cylinders 47, 48 arranged at the foot of the support arm 44. The hydraulic cylinders 47, 48 actuate racks which mesh with a ring gear arranged on the support arm 44. The pivotability of the rotating unit 43 achieved by the curved guide 53 ensures that the exchange unit 20 can always pull the tools 59 out of the tool magazine 19 in the same vertical orientation or hang them into the tool magazine 19, but during the changing process the tool into another (horizontal or oblique) can bring alignment that matches the respective orientation of the tool spindle 65. In this way, it is possible to replace the tool located in the tool spindle 65 without the tool spindle having to be moved back to a predetermined position. 8 to 10 show several exemplary tool changing processes in a snapshot. In Fig. 8 the tool spindle in the cutter bar 17 is vertical. In this case, the tool 59 can be changed without the exchange unit 20 or the turning unit 43 having to perform a pivoting movement during the transfer process. In Fig. 9, the cutter bar 17 is at an angle when the tool is changed. Here, the exchange unit 20 has to perform a swiveling movement on its way from the tool magazine 19 to the milling bar 17, so that the tools 59 can be exchanged unhindered. In the example in FIG. 10, the milling bar 17 lies horizontally. Here, the exchange unit 20 between the tool magazine 19 and the milling bar 17 must carry out the maximum pivoting movement by 90 °.

The entire procedure for changing a tool comprises the following steps:

1. The exchange unit 20, which is initially in a parking position, moves towards the tool magazine 19 in the longitudinal direction of the machine (FIG. 7).

2. The gripper 45 facing the tool magazine 19 clicks into a tool 59 hanging in the magazine under the lifting device 60.

3. The holding box (68 in FIG. 7) holding the tool 59 releases and is moved upwards by the lifting device 60. 4. The exchange unit 20 moves with the "new" tool to the position of the

Tool spindle 65, wherein pivoting takes place at the same time when the tool spindle is inclined or horizontal. 5. The other gripper 46 clicks into the “old” tool located in the tool spindle 65.

6. The clamping device on the tool spindle 65 loosens and the milling bar 17 moves back. 7. The rotating unit 43 rotates through 180 ° and exchanges the tools.

8. The milling bar 17 moves forward and the clamping device on the tool spindle 65 clamps the new tool.

9. The exchange unit 20 moves back to the tool magazine 19, the rotating unit 43 being pivoted back into the vertical basic position at the same time.

10. The holding box 68 is moved down by the lifting device 60 and the old tool is clamped.

11. The exchange unit 20 moves back into its parking position.

12. The tool magazine 19 positions a new tool at the removal point below the lifting device 60.

It goes without saying that the information about the respective alignment of the tool spindle 65 is given to the control of the changing unit 20 when the tool is changed, so that the latter can initiate and carry out a corresponding pivoting process.

Overall, the solution according to the invention, based on universal milling machines, results in the following situation:

Known universal milling machines are in most cases equipped with a pure horizontal or vertical milling spindle. If a combination is required, either vertical milling heads or manually / automatically distributable horizontal / vertical (H / V) milling heads are used. The attached milling heads have the disadvantage of the large amount of time required for the changeover. The automatic H / V ~ milling heads can only be positioned in either the horizontal or vertical position. In exceptional cases, intermediate positions can only be positioned in discontinuous steps of 1 ° or 2.5 °, whereby the major disadvantage which has to be accepted in the inclined position of the spindle. To do this, the traversing axes must make corrections.

If a tool changer is combined with these milling head systems, the milling head normally has to be returned to a preferred spindle position again and again. If both spindle positions are to be fed, the tool change device must be designed accordingly. With intermediate positions of the milling head, the travel axes are not parallel to the spindle axis in these systems. For an infeed axially to the spindle, 2 or 3 axes must always be adjusted. This is practically impossible when operated manually.

In the preferred embodiment of the present invention, on the other hand, a cross-slide system for the vertical and transverse axes is attached to an arcuate segment with a milling bar with an integrated milling spindle and is brought into the horizontal position by means of an arcuate movement in an arcuate guide by 90 ° (FIG. 10). The functions of the vertical axis and the transverse axis are interchanged. If any intermediate position on the curved guide is approached, the axial adjustment of the spindle axis always moves perpendicular to these axes. Compensatory movements are not to be carried out.

Due to the curved guidance without the actual journal bearing, the work area in the workpiece area remains collision-free.

The longitudinal table is adjusted horizontally on the machine bed. The height of the table does not change. Compared to swivel tables, this principle can accommodate a high workpiece weight. Even bulky workpieces can be clamped.

A stand unit screwed to the rear of the machine bed is provided with a curved guide on the side. The cross slide placed on the arch segment unit with the cutter bar is adjusted in this curved guide from vertical to horizontal position transversely to the longitudinal table axis. The sheet guide is driven by a manual or motorized drive via pinion and round rack. The backlash can be eliminated using a second mechanically coupled and tensioned pinion. A further spring pinion can be used to reduce the weight by means of a spiral spring system or an electric motor.

The machine can be used with and without an automatic tool changer. If a tool changer is used, - the tool magazine with the tool feeder system is placed outside the work area at the end of the machine bed. The new tool is already moved radially out of the magazine into a waiting position during the machining time. When the new tool is actually brought to the milling spindle, which is oriented differently depending on the angle adjustment, the tool is also brought into the corresponding angular position on a (second) curved guide (FIGS. 8 to 10).

LIST OF REFERENCE NUMBERS

10 machine tool (universal milling machine)

11 machine bed

12 long table

13 stand unit

14 bow guide

15 arc segment

16 cross slide unit

17 cutter bars

18 tool changer (automatic)

19 tool magazine

20 exchange unit

21 round rack

22 drive unit (arc segment)

23 gear

24 engine

25 worm gears

26 engine

27 engine

28 gearbox

29 spindle

30 engine

31 spindle

32,33,34 pinion

35.36 leadership

37 retaining bar

38 gearbox

39 sledges

40 holding plate

41 engine (with gear) spindle

rotary unit

Support arm, 46 grippers, 48 hydraulic cylinders

engine

bearing plate

arc

Round rack

Bow guide, 55 guide (rail), 57.58 roller shoe

Werleeug.

lifting device

spindle

Flange (stand unit)

carriage

roller shoes

tool spindle

drive shaft

roundtable

Bottle support

Claims

1. Machine tool (10), in particular a universal milling machine, with a table (12) for clamping a workpiece to be machined in a horizontal machining plane, and a tool spindle (65) which is in a pivoting plane perpendicular to the machining plane on a table ( 12) as a center circular circular path between a vertical position and a horizontal position is continuously pivoted, the tool spindle (65) being fastened to an arc segment (15) which is guided on an arc in a first arc guide (14), thereby characterized in that the first arc guide (14) has the shape of a circular arc section which surrounds the table (12) only on one side.

2. Machine tool according to claim 1, characterized in that the first curved guide (14) has approximately the shape of a semicircle, and that the curved segment (15) has a segment angle of approximately 90 °.

3. Machine tool according to one of claims 1 or 2, characterized in that on the first arc guide (14) a drive (24, 25, 66) for moving the tool spindle (65) is arranged, which with a first pinion (32) a round rack (21) attached to the arc segment (15) combs.

4. Machine tool according to claim 3, characterized in that the drive comprises a first motor (24) which drives a drive shaft (66) via a worm gear (25), and that the drive shaft (66) meshes with the first pinion (32) is.

5. Machine tool according to claim 4, characterized in that the drive shaft (66) with the first pinion (32) is helically toothed, and that the helical toothing is axially adjustable to cancel play.

6. Machine tool according to one of claims 3 to 5, characterized in that in addition to the first toothed pinion (32) a second mechanically coupled and braced toothed pinion (33) for eliminating the tooth play is arranged, which meshes with the round rack (21).

7. Machine tool according to one of claims 3 to 6, characterized in that on the first curved guide (14) a second motor (26) is arranged stationary, which drives a third pinion (34) via a gear (38), which third pinion (34) combs with the round rack (21) and applies a torque to the round rack (21) to compensate for the weight of the arc segment (15) and the tool spindle (65).

8. Machine tool according to one of claims 1 to 7, characterized in that a cross slide unit (16) is arranged between the tool spindle (65) and the arc segment (15), and that for adjusting the cross slide unit in the two orthogonal axes, two each with one Motor (27, 30) and a spindle (29, 31) equipped linear drives are provided.

9. Machine tool according to one of claims 1 to 8, characterized in that the machine tool (10) has an elongated machine bed (11) on which the table (12) is arranged, that on the machine bed (11) on one long side a stand unit (13) is attached, in particular screwed, which protrudes upward beyond the processing plane, and that the first sheet guide (14) is arranged on a side of the stand unit (13) lying transversely to the longitudinal direction of the machine bed (11).

10. Machine tool according to claim 9, characterized in that the table is designed as a longitudinal table (12) movable in the longitudinal direction on the machine bed (11).

11. Machine tool according to one of claims 1 to 0, characterized in that the tool spindle (65) is a milling spindle, and that the milling spindle is integrated in a milling bar (17) and is moved together with the milling bar (17).

12. Machine tool according to one of claims 1 to 11, characterized in that an automatic tool changer (18) is provided on the machine tool (10).

13. Machine tool according to claim 12, characterized in that the tool changer (18) a tool magazine (19) and a changing unit

(20) includes which exchange unit (20) transports tools (59) between the tool magazine (19) and the tool spindle (65)

14. Machine tool according to claim 13, characterized in that the tools (59) are held in the tool magazine (19) with a first, predetermined orientation, and that the exchange unit (20) means

(49, .., 53) with which the tools (59) can be pivoted from the first orientation into a second orientation during transport from the tool magazine (9) to the tool spindle (65), which corresponds to the respective orientation of the tool spindle ( 65) when changing the tool, or during transport from the tool spindle (65) to the tool magazine (19) can be pivoted from the second into the first orientation.

15. Machine tool according to claim 14, characterized in that the exchange unit (20) perpendicular to the pivoting plane of the tool spindle (65) between the tool magazine (19) and the tool spindle (65) can be moved, and that the pivoting means (49, .., 53 ) trained in this way are that the tool (59) can be pivoted in a plane parallel to the pivoting plane of the tool spindle (65).

16. Machine tool according to claim 15, characterized in that the pivoting means comprise a second sheet guide (53), in which a rotating unit (43) with grippers (45, 46) for the tools (59) is guided on a sheet movable.

17. Machine tool according to claim 16, characterized in that for moving the rotating unit (43) a motor provided with a drive is provided, in which a pinion meshes with a round rack (52)

18. Machine tool according to claim 16 or 17, characterized in that the pivoting means (49, .., 53) and the rotating unit (43) are arranged on a carriage (39) which is movable perpendicular to the pivoting plane of the tool spindle (65).

19. Machine tool according to claim 18, characterized in that a linear drive with a motor (41) and a spindle (42) is provided for moving the carriage (39).

20. The method for operating a machine tool according to claim 1, in which an automatic tool changer (18) is provided on the machine tool (10), characterized in that when a tool change, the tool spindle (65) of the machine tool (10) is in its respective position in the pivot plane is left, and that the tool changer (18) changes the tool (59) to be replaced in this position.

21. The method according to claim 20, characterized in that the tool changer (18) comprises a tool magazine (19) in which the tools (59) are held with a first, predetermined orientation, and that the tool changer (18) Tools (59) for transport from the factory Tool magazine (19) is pivoted to the tool spindle (65) from the first orientation into a second orientation, which corresponds to the respective orientation of the tool spindle (65) when changing the tool or during transport from the tool spindle (65) to the tool magazine (19) from the second pivoted back into the first orientation.