CA2277961A1

CA2277961A1 - Tool head for use in machine tools

Info

Publication number: CA2277961A1
Application number: CA002277961A
Authority: CA
Inventors: Erich Feil; Falk Hatzfeld; Roland Horl
Original assignee: Individual
Current assignee: Komet Praezisionswerkzeuge Robert Breuning GmbH
Priority date: 1997-01-23
Filing date: 1998-01-07
Publication date: 1998-07-30
Also published as: ATE209988T1; ES2167872T3; HK1022282A1; CZ259499A3; JP2001508366A; DE59802332D1; KR20000070407A; BR9807505A; WO1998032561A1; EP0966335B1; DE19702219A1; CZ292326B6; PL185746B1; EP0966335A1; PL334801A1; AU6292098A

Abstract

The invention concerns a tool head for use in machine tools. The tool head substantially comprises a basic body (10), a tool shank (16) which projects axially over the basic body (10) and can be coupled to a machine spindle, a tool holder (18) for a cutting tool (20) and a rotary slide (30) which supports the tool holder (18) eccentrically and can be rotated relative to the basic body (10), with adjustment of the cutting radius of the cutting tool (20), about an eccentric axis (28) parallel with the basic body axis (12). In order to ensure that the cutting geometry is constant during a cutting operation, the tool holder (18) can be adjusted in defined manner relative to the rotary slide (30) as a function of the adjusting angle thereof or of the cutting radius.

Description

' 1 n~
Tool head for use in machine tools Description The invention relates to a tool head for use in machine tools, comprising a base body, a tool shank which is disposed on the base body and which is adapted to be coupled to a rotating machine spindle, a tool holding fixture for a cutting tool, and a rotary slide which eccentrically carries the tool holding fixture and which is rotatable with respect to the base body, preferably about an eccentric axis parallel to the base body axis, thereby adjusting the cutting radius of the cutting tool.
In DE-A-196 17 877 it has been proposed for an application with a plane turning lathe head to provide as a working slide a rotary slide which is eccentrically disposed on the tool head, which rotary slide is rotatable by means of a drive sprocket and a gear rigidly connected to the rotary slide, thereby essentially radially adjusting the tool holding fixture. The rotation of the rotary slide results in no mass displacement, so that the provision of a compensating slide is not necessary. A disadvantage of this rotary slide, though, is that not only the distance of the cutting edges with respect to the base body axis is changed during an adjustment, but that also the alignment of the cutting edge with respect to the axis of rotation is changed.
Based on this it is the object of the invention to improve the known tool head of the type described above such that the cutting edge geometry can adapt during an adjusting process.

For the solution of this object the combination of features stated in patent claim 1 is proposed. Advantageous embodiments and further developments of the invention result from the dependent claims.
The solution according to the invention is based foremost on the idea that the tool holding fixture is adapted to be adjusted in a defined manner with respect to the rotary slide dependent on the rotary angle of the rotary slide or on the cutting radius. By this it is possible to hold constant the cutting edge geometry during an adjustment of the cutting radius. This can, for instance, be effected by the tool holding fixture being adapted to be adjusted with respect to the rotary slide aligning the cutting tool relative to the base body axis in a defined manner. This is expediently realized by the tool holding fixture being adjustable with respect to the rotary slide with the base body axis under alignment of a reference plane associated with the cutting tool. To this end the tool holding fixture can be disposed in an eccentric bore of the rotary slide such that it is rotatable about an axis which is parallel to the eccentric axis of the rotary slide.
According to a preferred embodiment of the invention there is provided an alignment rail which protrudes over the base body axis and which is rotatable about this axis, with respect to which alignment rail a reference plane which is associated with the tool holding fixture or the cutting tool is adapted to be aligned during the adjustment of the rotary slide.
According to an alternative embodiment of the invention the rotary slide and the tool holding fixture are coupled to each other and to the base body by transmission means, wherein the transmission means are expediently formed.to.be a gear transmission.
According to a preferred further development of this principle the rotary slide is rotatably borne in an eccentric bore of the base body, while the tool holding fixture is rotatably borne in an eccentric bore of the rotary slide. Transmission means on the side of the rotary slide are disposed between a base-body-fixed or machine-side drive mechanism and the rotary slide, while transmission means on the side of the tool holding fixture are disposed between the tool holding fixture and the base body. In this, the adjustment of the cutting edge is effected by the transmission means on the side of the rotary slide and the transmission means on the side of the tool holding fixture having a defined transmission ratio.
The transmission means on the side of the rotary slide expediently comprise a toothed ring which is adapted to be driven by the drive mechanism, which is concentric with respect to the base body axis, and which is preferably designed to be an internally toothed ring, and comprising a toothed ring meshing with the former, which is preferably designed to be a rotary-slide-fixed externally toothed ring, while the transmission means on the side of the tool holding fixture comprise a base-body-fixed gear and a tool-holding-fixture-fixed toothed ring meshing therewith and preferably being formed to be an internally toothed ring.
In order to be able to transfer the forces occurring during the cutting and adjusting processes without free play, the rotary slide is borne in an axial/radial bearing which is disposed in the eccentric bore and which is preferably formed to be a tapered roller bearing. Due to the limited available space at least part of the toothed,rings and the associated parts are formed segment-like, wherein it must, be taken into consideration that in these regions there are no full rotations but only partial rotations of the parts.
Due to the eccentric arrangement of the cutting tool on the rotary slide an imbalance results, which can be compensated by providing balancing weights in the rotary slide as well as in the base body. A considerable advantage of the rotary slides is that the imbalances can be designed to be symmetrical. This means that they are mass-symmetrical with respect to their respective axis of rotation. Therefore, a precise balancing of the tool head with respect to its axis of rotation is possible, without the need for providing a compensation slide.
According to a further embodiment of the invention a round slide is rotatably borne in a concentric bore of the base body, the rotary slide is rotatably borne in an eccentric bore of the round slide, the tool holding fixture is rotatably borne in an eccentric bore of the rotary slide, wherein the round slide is rotatable, taking along the rotary slide and the tool holding fixture, about the base body axis by means of a base-body-fixed or machine-side drive mechanism, and wherein transmission means are disposed between the base body on the one hand and the rotary slide and the tool holding fixture on the other hand, which transmission means are matched to each other by way of a defined transmission ratio. The rotary slide carries as transmission means a toothed ring which is concentric with respect to it axis of rotation, with which it rolls off on a base-body-fixed toothed ring which is preferably formed to by an internally toothed ring. On the other hand, the tool holding fixture expediently carries a - toothed ring which is concentric with respect to its axis of rotation, with which it rolls off on a base-body-fixed toothed ring which is preferably formed to be an internally toothed ring, if need be over an interposed intermediate 5 gear loosely borne on the rotary slide. The eccentricities of the eccentric bores in the round slide and the rotary slide advantageously are of equal magnitude.
The drive mechanism advantageously comprises a rotary rod which is coaxial with respect to the base body axis and which is driven from the machine side or an intermediate transmission having a driven shaft which is concentric with respect to the base body axis. The intermediate transmission may therein be designed to be a rotary reducing gear unit or a translation-to-rotation conversion gear unit. Advantageously, the rotary reducing gear unit is designed to be a planetary gear unit or a harmonic drive gear unit having drive and driven axes which are coaxial with respect to each other.
In principle it is possible to provide separate drive means which can be electronically coupled to each other for the rotary slide, the round slide and the tool holding fixture.
This makes it possible to fashion the adjustment rules for the tool holding fixtures in dependency on the rotary slide adjustment to be largely arbitrary. In this way the chip forming can be influenced, for instance when machining work pieces consisting of different materials. Moreover, the service life of the cutting edges can be extended in this manner.
For monitoring the adjustment path a preferably electronic angle or displacement measuring system measuring the adjusting angle of the rotary slide or of the round slide - or the displacement of the cutting tool can be provided in the base body.
According to a further advantageous embodiment of the invention at least two rotary slides having adjustable tool holding fixtures are provided, which are disposed in eccentric bores of the base body or of the round slide and which can be driven in unision or seperately.
In the following the invention will be further described with reference to embodiment schematically shown in the drawing, in which:
Fig. la shows a section through a tool head designed to be a plane turning lathe head having an eccentric rotary slide;
Fig. lb shows a plan view of the tool head with the tool holding fixture;
Fig. lc shows a section through the tool head in the region of the gear transmission;
Fig. ld shows a section through the rotary slide;
Fig. 2a and b schematically show a plan view of the tool head in two rotary positions of the rotary slide;
Fig. 3a shows a plan view of an embodiment of a plane turning lathe head which is modified with respect to Fig. l;
Fig. 3b shows a section along the line B-B in Fig. 3a;

Fig. 3c shows a section through the tool head rotated b.y 90° with respect to Fig. 3b;
Fig. 3d shows a section along the line D-D in Fig. 3a;
Fig. 4a shows a section through a tool head modified with respect to Fig. 1 and 3 and having a concentric round slide and an eccentric rotary slide;
Fig. 4b and c schematically show a plan view of the tool head according to Fig. 4a in.two different angular positions of the round slide;
Fig. 5 shows a schematic plan view of a modified tool head comprising an alingment rail;
Fig. 6a shows a diagram for calculating the cutting radius and the correction angle of a tool head having a rotary slide in a simplified representation;
Fig. 6b and c show two diagrams s = s(a) and b = 8(a);
Fig. 7 shows a model for calculating the cutting radius (x) and the correction angle (8) of the cutting insert for a tool head with an arrangement of the rotary slide in the base body, which has been generalized with respect to Fig. 6a.
The tool heads shown in the drawing are intended to be used as plane turning lathe heads in machine tools. The tool heads essentially consists of a base body 10 which is rotatable about an axis of rotation 12, a tool shaft 16 which axially protrudes over the base body and can be.
coupled to a mchine spindle 14 (Fig. 4a), a toll holding fixture 18 for a cutting tool 20, a cutting insert 26 which has a cutting edge 24 and which is disposed on the cutting tool 20, and a rotary slide 30 which carries the tool holding fixture 18 in an eccentric bore 22 and which is rotatable with respect to the base body 10 about an eccentric axis 28 parallel to the base body axis 12, thereby adjusting the cutting radius of the cutting edge 24. To this end, the rotary slide 30 is borne in an eccentric bore 32 of the base body 10 (Fig. 1 and 3) or of a round slide 34 (Fig. 4) by means of roller bearings 36.
In the case of Fig. 4 the round slide 34 is in turn borne in roller bearings 38 in a bore 40 which is concentric with respect to the axis of rotation 12. The tool holder fixture 18 is, in the case of Fig. 1 and 3, borne with its cylindrical surface in a plain bearing which forms the eccentric bore 22, while in the case of Fig. 4 it is additionally supported in the eccentric bore 22 by a roller bearing 42.
As can be seen especially from Fig. la, 3c and d as well as Fig. 4b, the eccentric bores 22, 32 have in the embodiments shown the same eccentricity e. An imbalance is created by the eccentric arrangement of the cutting tool 20 in the rotatary slide 30 on the one hand and by the eccentric arrangement of the rotary slide 30 in the base body 10 or in the round slide 34 on the other hand, which imbalance can be balanced by balancing weights 44 in the rotary slide 30 and balancing weights 46 in the base body 10 or in the round slide.

A substantial advantage of the rotary slide is that imbalances with respect to the axis of rotation 12 of,the~
base body can be balanced mass-symmetrically. The rotation of the rotary slide does not result in a mass shift, so that a compensating slide is not needed. Therefore only a relatively small drive power which is independent of the adjusting path is needed.
In the embodiments shown in Fig. 1 to 3 the rotary slide 30 is driven by a a machine-side drive mechanism having a rotary rod or driven shaft 48 which is concentric with respect to the axis of rotation 12. The drive mechanism comprises a conversion transmission to slow speeds, the machine-side drive shaft 47 of which and the head-side driven shaft 48 of which are disposed coaxially with respect to each other. The transmission ratio of the conversion transmission is expediently chosen to lie between 10:1 and 1000:1, preferably about 100:1.
The driven shaft 48 carries at its face end a segment-like internally toothed ring 50 which meshes with an externally toothed ring 52 of smaller diameter on the rotary slide 30 and which has no free play with respect thereto. When rotating the rotary slide 30 the tool holding fixture 18 is carried along, thereby adjusting the cutting radius of the cutting edge 24. In order to compensate the cutting geometry (alignment of the cutting edge with respect to the axis of rotation 12) during the adjustment of the cutting tool, the tool holding fixture 18 carries an internally toothed ring 54 which is concentric with respect to the axis of the tool holding fixture 18, which ring meshes with a base-body-fixed gear 58 which can be formed onto a base-body-fixed holder 11. The transmission ratios of the transmission means formed by the internally toothed ring 50 and the externally toothed ring 52 on the one hand and the transmission means formed by internally toothed ring 54 and the gear 58 on the other hand are matched to each other such that the cutting insert 26 is aligned relative to the 5 axis of rotation 12 with its reference plane 60 in each rotary position of the rotary slide 30. In the embodiment shown in Fig. 2a and b the cutting insert 26 is adjusted by a correction angle S = 15° for an angle of rotation a = 30°
of the rotary slide 30. At the same time the cutting 10 diameter is increased from initially 50 mm to 54.14 mm.
In the embodiment according to Fig. 4a to c the round slide 34 is rotated concentrically with respect to the base body 10 by means of the rotary rod or driven shaft 48. The driven shaft 48 in turn is driven by a drive mechanism which comprises a machine-side pull rod 51 and a translation-to-rotation conversion transmission 47'. The displacement effected by the pull rod 51 in the direction of the double arrow 49 is converted into the desired rotation of the driven shaft 48 in the direction of the arrow 53 by means of the conversion transmission 47'. The drive mechanism and the transmission means can be arranged in an interpenetrating manner within the base body 10 such that a relatively short length results. The rotary slide 30 which is disposed in the eccentric bore 32 of the round slide as well as the tool holding fixture which is disposed in the eccentric bore 22 are carried along in the direction of rotation by the driven shaft 48. The rotary slide 30 carries an externally toothed ring 62 for the adjustment of the rotary slide 30 with respect to the round slide 34 and the base body 10, which ring 62 meshes with a base-body-fixed internally toothed ring 64. Furthermore, the tool holding fixture 18 carries an externally toothed ring 66 which is concentric with respect to the axis. thereof, which ring 66 meshes with a base-body-fixed internally toothed.
ring 70 by way of an intermediate gear 68 which is loosely positioned on the rotary slide axis 28. The transmission ratios of the transmission means formed by the described toothed rings are matched to each other such that upon adjusting the cutting radius of the cutting insert 26 the reference plane 60 associated with the cutting insert 26 is aligned with respect to the axis of rotation 12 (cf. the transition between Fig. 9b and c).
In the embodiment of a tool head schematically shown in plan view in Fig. 5 the rotary slide 30 which is borne rotatably about the eccentric axis 28 in the base body 10 is also fitted with a tool holding fixture 18 which is rotatably positioned in an eccentric bore 22 of the rotary slide. The alignment of the reference. plane 60 of the cutting insert 26 with respect to the axis of rotation 12 of the tool head is in this instance performed by means of an alignment rail 72 which is rotatable on the base body 10 about the axis of rotation 12 and which lies against the reference plane 60 of the cutting insert 26 with its alignment surface 74 and which rotatably carries along the tool holding fixture 18 in its eccentric bore 22 during the adjusting process. The alignment rail 72 therefore fulfills the same function as the gear transmissions according to Fig. 1 to 4.
In the embodiment shown in Fig. 6a there is provided a displacement path measuring system which comprises a rule 80 which is connected to the cutting insert carrier and a measuring head 82 which is disposed on the alignment rail 72. With these means an absolute measurement of the adjusting path of the cutting insert 24 with.respect to the base body 10 is possible. , , In the diagram of Fig. 6a the displacement and angle relationships are shown for the simplified case of the adjusting path of the cutting insert 24 running through the axis of rotation 12 from the sarting point, from which relationships the following formula for the cutting radius s(a) and for the correction angle of the cutting edge 8(a) can be derived.
The cutting radius with respect to the base body axis 12 in dependency of the angle a of the rotary slide in this case is s(a) = r 2(1- cosa) (1 ) wherein r denotes the cutting radius with respect to the eccentric axis 28 and therefore the eccentricity of the rotary slide 30.
For the correction angle 8 being a function of the angle of rotation a the following relationship results 8 = a/2 ~ (2~.
The relationships according to the equations (1) and (2) are shown in the graphs of Fig. 6b and c.
The diagram of Fig. 7 shows the paths and angles which are necessary for calculating the cutting radius x and the correction angle 8' for the general case of the rotary slide eccenter being disposed out of center.

From this the equation for the cutting radius x as a function of the angle of rotation a of the rotary slide follows as x(a)=Ja2+2r2(1-casa)+4arsina(a/2) (3) wherein r denotes the radius of the cutting insert 26 with respect to the eccentric axis 28 of the rotary slide 30, and a denotes the smallest cutting radius with respect to the axis of rotation 12. For the correction angle 8' in denpendency of the angle of rotation a the equation a 1 + cosa (4) 8 ~ (a) = a / 2 + 90°- arcsin ~x(a) follows, wherein x(a) is to be substituted from equation (3) .
The definition of the correction angle 8' differs from the definition of the correction angle 8 of equation (2) by an angle of 90°.
The angles (3, y, and s and the path s additionally shown in the diagram of Fig. 7 are needed for the derivation of equations ( 3 ) and ( 9 ) .
In summary the following is to be stated: The invention relates to a tool head for use in machine tools. The tool head essentially consists of base body 10, a tool shank 16 which is disposed on the base body 10 and which is adapted to be coupled to a rotating machine spindle 14, a tool holding fixture 18 for a cutting tool 20, and a rotary slide 30 which eccentrically carries the tool holding fixture 18 and which is rotatable with respect to th~,ba5e body 10, preferably about an eccentric axis 28 parallel to the base body axis 12, thereby adjusting the cutting radius of the cutting tool 20. In order to ensure a constant cutting geometry during a cutting process the tool holding fixture 18 is adapted to be adjusted in a defined manner with respect to the rotary slide 30 dependent on the rotary angle of the rotary slide 30 or on the cutting radius.

Claims

claims

1. A tool head for use in machine tools, comprising a base body (10), a tool shank (16) which is disposed on the base body (10) and which is adapted to be coupled to a rotating machine spindle (14), a tool holding fixture (18) for a cutting tool (20), and a rotary slide (30) which eccentrically carries the tool holding fixture (18) and which is rotatable with respect to the base body (10), preferably about an eccentric axis (28) parallel to the base body axis (12), thereby adjusting the cutting radius of the cutting tool (20), characterized in that the tool holding fixture (18) is adapted to be adjusted in a defined manner with respect to the rotary slide (30) dependent on the rotary angle (.alpha.) of the rotary slide (30) or on the cutting radius (s, x).

2. The tool head of claim 1, characterized in that the tool holding fixture (18) is adapted to be adjusted with respect to the rotary slide (30) aligning the cutting tool (20) relative to the base body axis (12) in a defined manner.

3. The tool head of claim 1 or 2, characterized in that the tool holding fixture (18) is adjustable with respect to the rotary slide (30) with the base body axis (12) under alignment of a reference plane (60) associated with the cutting tool (20).

4. The tool head of one of claims 1 to 3, characterized in that the tool holding fixture (18) is disposed in an eccentric bore (22) of the rotary slide (30) such that it is rotatable about an axis which is parallel to the eccentric axis (28) of the rotary slide.

5. The tool head of one of claims 1 to 4, characterized by an alignment rail (72) which protrudes over the base body axis (12) and which is rotatable about this axis, with respect to which alignment rail a reference plane (60) which is associated with the tool holding fixture (18) or the cutting tool (20) is adapted to be aligned during the adjustment of the rotary slide (30).

6. The tool head of one of claims 1 to 5, characterized in that the rotary slide (30) and the tool holding fixture (18) are coupled to each other and to the base body by transmission means (50, 52, 54, 58; 62 64, 66, 68, 70;
72, 74, 60).

7. The tool head of claim 6, characterized in that the transmission means comprise gears, toothed rings and/or toothed racks.

8. The tool head of claim 6 or 7, characterized in that the transmission means are adapted to be actuated without free play.

9. The tool head of one of claims 6 to 8, characterized in that the transmission means comprise on the drive side a rotary reducing gear unit (47) or a translation-to-rotation conversion gear unit (47').

10. The tool head of claim 9, characterized in that the rotary reducing gear unit (47) is designed to be a planetary gear unit or a harmonic drive gear unit having drive and driven axes (45, 48) which are coaxial with respect to each other.

11. The tool head of claim 9 or 10, characterized in that the reducing gear unit (47) or the conversion gear unit (47') and the transmission means coupled thereto are disposed within the base body, preferably in a radially interpenatrating manner.

12. The tool head of one of claims 1 to 11, characterized in that for the cutting radius of the tool head in dependency of the angle (.alpha.) of rotation of the rotary slide (30) about its eccentric axis (28) the relation and for the correction angle .delta.'(.alpha.) of the reference plane (60) of the cutting tool (20) the relation are valid, wherein r denotes the cutting radius with respect to the eccentric axis of the rotary slide (eccentricity) and a denotes the smallest cutting ratio with respect to the base body axis (12).

13. The tool head of one of claims 1 to 12, characterized in that for the cutting edge intersecting the base body axis (12) in a starting position (a = 0) the relation is valid for the cutting radius s in dependency of the angle of rotation .alpha. of the rotary slide (30) and .delta. = .alpha./2 is valid for the correction angle, wherein r denotes the eccentricity of the rotary slide (30).

14. The tool head of one of claims 1 to 13, characterized in that the rotary slide (30) is rotatably borne in an eccentric bore (32) of the base body (10), that the tool holding fixture (18) is rotatably borne in an eccentric bore (22) of the rotary slide (30), that transmission means (50, 52) on the side of the rotary slide are disposed between a base-body-fixed or machine-side drive mechanism (rotary rod, driven shaft 48) and the rotary slide (30), that transmission means (54, 56, 58) on the side of the tool holding fixture are disposed between the tool holding fixture (18) and the base body (10), and that the transmission means on the side of the rotary slide and the transmission means on the side of the tool holding fixture have a defined transmission ratio.

15. The tool head of claim 14, characterized in that the transmission means on the side of the rotary slide comprise a toothed ring which is adapted to be driven by the drive mechanism (rotary rod, driven shaft 48), which is concentric with respect to the base body axis (12), and which is preferably designed to be an internally toothed ring (50), and comprising a toothed ring meshing with the former, which is preferably designed to be a rotary-slide-fixed externally toothed ring (52).

16. The tool head of claim 14 or 15, characterized in that the transmission means on the side of the tool holding fixture comprise a base-body-fixed gear (58) and a tool-holding-fixture-fixed toothed ring meshing therewith and preferably being formed to be an internally toothed ring (54).

17. The tool head of one of claims 1 to 16, characterized in that at least part of the toothed rings and the associated parts are formed segment-like (Fig. 1c).

18. The tool head of one of claims 1 to 13, characterized in that a round slide (34) is rotatably borne in a concentric bore (40) of the base body (10), that the rotary slide (30) is rotatably borne in an eccentric bore (32) of the round slide (34), that the tool holding fixture (18) is rotatably borne in an eccentric bore (22) of the rotary slide (30), that the round slide (34) is rotatable, taking along the rotary slide (30) and the tool holding fixture (18), about the base body axis (12) by means of a base-body-fixed or machine-side drive mechanism (rotary rod, driven shaft 48), that transmission means (62, 69, 66, 68, 70) are disposed between the base body (10) on the one hand and the rotary slide (30) and the tool holding fixture (18) on the other hand, which transmission means are matched to each other by way of a defined transmission ratio.

19. The tool head of claim 18, characterized in that the rotary slide (30) carries a toothed ring (62) which is concentric with respect to it axis of rotation (28), with which it rolls off on a base-body-fixed toothed ring which is preferably formed to by an internally toothed ring (64).

20. The tool head of claim 18 or 19, characterized in that the tool holding fixture (18) carries a toothed ring (66) which is concentric with respect to its axis of rotation, with which it rolls off on a base-body-fixed toothed ring which is preferably formed to be an internally toothed ring (70), if need be over an interposed intermediate gear (68) loosely borne on the rotary slide (30).

21. The tool head of one of claims 14 to 20, characterized in that the drive mechanism comprises a rotary rod which is coaxial with respect to the base body axis (12) and which is driven from the machine side.

22. The tool head of one of claims 14 to 21, characterized in that the drive mechanism comprises an intermediate transmission having a driven shaft (48) which is concentric with respect to the base body axis (12).

23. The tool head of one of claims 18 to 22, characterized in that the eccentricities of the eccentric bores (32, 22) in the round slide (34) and the rotary slide (30) are of equal magnitude.

24. The tool head of one of claims 1 to 23, characterized by an angle or displacement measuring system (80, 82) measuring the adjusting angle of the rotary slide (30) or of the round slide (34) or the displacement of the cutting tool (20).

25. The tool head of one of claims 1 to 29, characterized by balancing weights (49, 46) disposed in the rotary slide (30) and/or the base body (10) and/or the round slide (34) for balancing the tool head with respect to the base body axis (12).

26. The tool head of one of claims 1 to 25, characterized in that separate drive means which can be electronically coupled to each other are provided for the rotary slide (30) and the tool holding fixture (18).

27. The tool head of one of claims 1 to 26, characterized in that at least two rotary slides having adjustable tool holding fixtures are provided, which are disposed in eccentric bores of the base body or of the round slide and which can be driven in unision or seperately.