CN109648652B

CN109648652B - Milling tool for processing wood, wood material, synthetic material or light metal

Info

Publication number: CN109648652B
Application number: CN201811184672.7A
Authority: CN
Inventors: J·格雷夫; H·埃伦斯伯格; A·基瑟尔巴赫
Original assignee: Leitz GmbH and Co KG
Current assignee: Leitz GmbH and Co KG
Priority date: 2017-10-11
Filing date: 2018-10-11
Publication date: 2022-03-08
Anticipated expiration: 2038-10-11
Also published as: DE102017123681C5; DE102017123681B4; EP3470190B1; EP3470190A1; DE102017123681A1; CN109648652A

Abstract

A milling tool for machining wood, wood material, synthetic material or light metal, having a machining side (A) and a spindle side (B) and having a stationary first machining tool (1) arranged in a housing (11) rotatable about an axis of rotation (D) and at least one second machining tool (2, 3) which is arranged coaxially with respect to the first machining tool (1) movably between a rest position and a machining position. According to the invention, the at least second machining tool (2, 3) can be connected to a cam disk (7) which is arranged rotatably in the housing (11) about a rotational axis (D) in order to be moved in the axial direction.

Description

Milling tool for processing wood, wood material, synthetic material or light metal

Technical Field

A milling tool for machining wood, wood material, synthetic material or lightweight metal, having a machining side and a screw side and having a stationary first machining tool arranged in a housing rotatable about an axis of rotation and at least one second machining tool which is arranged coaxially with respect to the first machining tool movably between a rest position and a machining position.

Background

Such milling tools are used for forming corners and edges on plate-shaped workpieces. In the case of varying edge strip thickness, the section radius of the milling tool must also be adapted to the edge strip thickness. In small lot manufacturing, frequent tool changes occur with manufacturing interruptions. For this reason, several solutions with switchable tools have been developed in order to be able to perform the profile change without tool removal and installation. Partly even with the tool rotated.

The milling tool described at the outset is disclosed, for example, in DE 19915672 a 1. Differently profiled tools are arranged with the machining tools arranged coaxially to one another. The tool with the largest radius is always in the machining position. For the purpose of changing the cross section, the other profiled tool with the smaller radius is moved into its machining position and completely covers the cross section of the first tool, except for the contour bevel on the circumferential side. The change of the tool cross section is effected by a linear movement of one of the movably arranged machining tools, which is pneumatically triggered. A disadvantage is that for each movable machining tool, a separate actuation is required, which leads to a complex design when there are more than two differently shaped tools.

DE 102013010359 a1 discloses a milling tool in which differently shaped tools are not moved axially but rather radially into their machining position. For this purpose, the tool is arranged on a radially displaceable tool carrier and the pneumatically triggered axial movement of the coaxially arranged operating element is converted into a radial movement of the tool carrier via a conical bevel. Even in the case of milling tools, individual control operations must be carried out for each movable machining tool. The working tool which is not in the working position must be stopped by pneumatic pressure against the acting centrifugal force, which requires a high setting force at high rotational speeds.

In the milling tool disclosed in DE 202010010704, the individual machining tools are mounted individually in the tool head and are axially displaceable. In this way, the individual working tools can be simply brought from the rest position into the processing position. The machining tool is fixedly positioned in the machining position. The undesired working tool is retracted into its rest position. During machining, the activated machining tool must always be held in its machining position by an external force against the cutting pressure and the spring return force. Since the individual working tools are arranged outside the axis of rotation, the rotational speed-dependent centrifugal forces act on the working tools, which requires a very high bearing in order to avoid a diameter widening of the tool under load.

DE 102014008033 a1 discloses a milling tool in which differently shaped tools are arranged on a rotationally adjustable tool holder. The profile change is carried out by a defined synchronous rotational movement of the tool holder. Without increasing the complexity, more than three sections can also be changed in the milling tool.

DE 7426183U discloses a milling tool which consists of two tool bodies which are connected in a form-fitting manner with respect to one another and which are designed approximately symmetrically and support a tool. The tool bodies are arranged movably relative to each other via a threaded rod.

US 4,551,165 a discloses an automatic cutting edge changer for changing tools on a tool. If the sensor detects wear or chipping on the tool edge, the tool edge changer moves the tool plate out of its cutting position and inserts a new tool.

The multiple-profile milling device disclosed in DE 102011004536 a1 is equipped with a first tool in a working state and a second tool which is placed in a working position. An additional screw is provided between the moving cylinder for the second tool and the tool. When the second tool is in the working state, the machining cross-section of the second tool overlaps the machining cross-section of the first tool, so that the tool to be machined acquires the second tool cross-section.

DE 102013226214 a1 discloses a device for machining workpieces made of wood, wood material, synthetic material or the like, having two milling tools for the contour machining of the edges of the workpiece. The second milling tool is adjustable relative to the first milling tool between a rest state, in which the first milling tool can be engaged with the workpiece, and a machining state, in which the second milling tool can be engaged with the workpiece. The edge on the workpiece can be milled flush via a third milling tool which is arranged coaxially with respect to the two further milling tools.

Disclosure of Invention

The object of the invention is to enable an automatic profile change of at least two, preferably three or more profiles with a fixed tool and a tool change to be carried out in a process-safe manner.

The object is achieved by the independent claims. Advantageous embodiments specify the dependent claims.

In order to solve the problem, a milling tool of this type is characterized in that at least a second machining tool can be connected for movement in the axial direction to a cam disk which is arranged in the housing so as to be rotatable about an axis of rotation.

With this configuration, the means for changing the cross-section take up little installation space and the milling tool is simple to design. Basically, a plurality of second processing tools may be provided. Preferably, the cam disc provided with cams directed in the axial direction can be rotated progressively. It is thereby possible to place the working tool in its processing position by an axial back-and-forth movement.

For this purpose, the first machining tool is preferably rigidly connected to a base body, which is coupled to the housing in a rotationally fixed manner. Particularly preferably, the machining tool is screwed to the base body.

The cam disk can be connected to a sleeve-like pressure ring which has at least one, preferably three, radially inwardly projecting balls (as a sliding ring mechanism) which run in a meandering circumferential groove of a locking sleeve connected to the housing in a rotationally fixed manner and which forms a sliding ring guide, wherein the inner diameter of the pressure ring is greater than the outer diameter of the locking sleeve.

The ball or balls are preferably arranged (with play) in a radial bore in the inner wall of the pressure ring and are here preferably adjustable radially toward the detent sleeve via grub screws.

If the meander is extended at an acute angle (zigzag formation) so that the at least one ball is either pressed clockwise or can only be guided counterclockwise, no turning point is formed when the direction of the lifting movement is reversed. For this reason, it is preferable to provide an overlapping portion along the rolling direction of the ball at the turning point of the groove.

The cam disk is preferably connected in a rotationally fixed manner to the pressure ring and is connected movably in the axial direction. Advantageously, a pressure spring acting in the axial direction is arranged between the pressure ring and the base body.

Furthermore, it is advantageous if each of the movably arranged machining tools has cylindrical pins regularly spaced apart on a partial circle, which extend parallel to the rotational axis and are operatively connected to cams arranged on the cam disk. The engagement of the cam disks with the respective working tools is thereby simplified.

The at least one pressure spring is preferably guided axially in a spring ring and the spring ring is mounted rotatably relative to the pressure ring via an axial bearing. One or three compression springs are arranged between the stationary working tool and one or more different working tools (at least a second working tool).

The pressure ring can be provided with a closed-loop end face on the screw side, which end face serves as a rolling surface for the rolling elements. With this design, the operating force for setting the machining position of the machining tool is reduced.

Each machining tool is preferably provided with a plurality of tools, wherein the tools are identically shaped at each individual machining tool, but each of the machining tools has differently shaped tools. It is conceivable for both machining tools to have identically shaped tools.

Preferably, the cross-section of the tool is a radius or chamfer and the fixed machining tool carries the tool with the largest radius.

If the pressure ring is provided with markings for the respective tool on the screw side, these markings can interact with markings in the housing, which can reduce the respective effective tool cross section and make it visible to the observer depending on the rotational position of the pressure ring.

The machining device provided with the tool designed according to the invention has an axially movable operating device with which the disengaging movement and the return stroke can be guided, and the operating device has at least one pressure element and one rolling element. The pressure element is preferably a spring-loaded bolt and the rolling elements are spherical rollers.

A method for operating a machining device is characterized in that, during a disengagement movement of an actuating element, in a first step, the contact between an axially movable actuating tool and a cam disk is separated, in a second step, the cam disk is set into rotation by means of a meandering groove in a latching sleeve and at least one ball in a pressure ring, the rotational movement of the cam disk ends in a subsequent return stroke of the actuating element, and in a third step, at the end of the return stroke, the axially movable machining tool again bears against the cam disk.

Drawings

Embodiments of the device according to the invention are explained below with the aid of the drawings. In the drawings:

fig. 1 shows an exploded view of a milling tool;

figure 2 shows another exploded view of the milling tool according to figure 1,

fig. 3 shows a perspective view of a milling tool with an operating device from the machining side;

fig. 4 shows a perspective view of the tool with the operating device from the screw side;

fig. 5 shows an axial section of a milling tool;

FIG. 6 shows an exploded view of the adjustment mechanism;

FIG. 7 shows a half-section view of the adjustment mechanism;

fig. 8 shows a perspective cross-sectional view through the milling tool from the machining side;

fig. 9 shows a perspective cross-sectional view through the milling tool from the screw side;

fig. 10 shows a cross-sectional view of a milling tool with a fixed machining tool in a machining position;

FIG. 11 shows an axial cross-sectional view of the tool during a first stage of cross-sectional transformation;

FIG. 12 shows the view according to FIG. 11 during the second extreme of the profile change;

fig. 13 shows a view of the tool according to fig. 11 during a third phase;

fig. 14 shows a view of the tool according to fig. 11 during a fourth phase;

fig. 15 shows a view of the milling tool according to fig. 11 after the end of the section change;

fig. 16 shows a perspective view of the milling tool without the base body and the housing;

fig. 17 shows a side view of the milling tool according to fig. 16;

fig. 18 shows a view of the milling tool according to fig. 16 with a first machining tool movably arranged in a first machining position;

fig. 19 shows a side view of the milling tool according to fig. 18;

fig. 20 shows a view of the milling tool according to fig. 16 or 18 with a second machining tool movably arranged in a second machining position;

fig. 21 shows a side view of the tool according to fig. 20;

fig. 22 shows a principle view of the sectional transformation.

Detailed Description

The milling tool according to the invention is composed of a base body 4, which carries a first machining tool 1 fixedly connected via a screw 29, having a first tool section 31; and at least one second axially movable working tool 2 having a second tool cross-section 32. The base body 4 is formed with a flange region 30 having a bore for receiving the working

tool

1, 2, 3 and an interface, for example a bore 25, for fastening to a rotatable drive (machine screw, not shown), advantageously having a conical bore for play-free centering. On the circumferential side, the milling tool is closed by a housing 11 which is connected to the base body 4 in a rotationally fixed and axially movable manner by means of a grub screw 40 which engages in a corresponding recess 44 in the base body 4 (see fig. 5).

The exemplary embodiment shown has a tool 1 which is fixedly screwed to the base body 4 and has a cutting section 31; and has two axially

displaceable machining tools

2, 3, each having a cutting

tool cross section

32, 33, which are guided on different coaxially arranged cylinder faces of the basic body 4. Via the

springs

26, 27, the

movable working tools

2, 3 are tensioned in the axial direction relative to the fixed tool 1, and via the cylindrical pins 37, 38, the working tools are connected in a rotationally fixed and axially movable manner to the base body 4. Cylindrical pins 37, 38 extend through bores 37.1, 38.1 in the flange of the base body 4 in order to interact with the cam disk 7. The axially

movable working tools

2, 3 are pressed away from the fixed tool 1 by means of

springs

26, 27. The cam disk 7 with the cams 17 projecting in the axial direction is rotatably mounted in the base body 4 and is fixed in the axial direction by means of the fastening ring 10.

The axial position of the

movable working tools

2, 3 is changed by the angular position of the cam disk 4 between the operating position and the rest position. If the cam 17 is positioned such that neither of the working

tools

2, 3 is in contact with the cam via the cylindrical pins 37, 38, the two axially

movable working tools

2, 3 rest with their back flat faces 39 on the basic body 4 and the

tool sections

32, 33 are out of the working position (in the rest position). The stationary working tool 1 is in the working position. If the cam 17 is positioned such that one of the two axially

movable working tools

2, 3 rests with its

cylindrical pin

37, 38 on the cam 17 of the cam disk 7, this working

tool

2, 3 is in the working position with its cutting section.

Advantageously, the different edge sections (radii and chamfers) to be produced are distributed to the

machining tools

1, 2, 3, so that the fixed machining tool 1 has the largest section radius and the smallest section radius and chamfer section are assigned to the

different machining tools

2, 3. If all the

prop sections

31, 32, 33 are designed such that they have the same reference point for "cementing" in the working position, the section of the stationary working tool 1 always coincides with the section of the axially

movable working tools

2, 3, so that only the axially

movable working tools

2, 3 are given a section.

The cam disk 7, together with the locking sleeve 5 and the pressure ring 9, forms the actual adjusting mechanism for the profile change. For this purpose, the locking sleeve 5 is fixedly connected to the housing 4, for example via a grub screw 34. The latching sleeve 5 has a circumferential groove 18 extending substantially in the shape of a sawtooth on its circumference, which serves as a sliding ring for guiding the sliding ring. The groove 18 has a semicircular cross section and serves as a rolling track for the at least one ball 19. In the circumferential direction, the detent sleeve 5 interacts with a pressure ring 9, which is movably connected to the detent sleeve 5 via at least one ball 19, preferably three balls, by means of a groove 18. The movement between the catch sleeve 5 and the pressure ring 9 is positively guided by the zigzag-shaped course of the groove 18. The pressure ring 9 is in turn connected in a rotationally fixed and axially displaceable manner to the cam disk via a projection 15, which engages in a groove 16 of the cam disk 7.

In order to perform the cross-sectional change, the milling tool is pressed in the rest state thereof in the axial direction against the housing 11 and the pressure ring 9 via an actuating device 21 arranged on the drive side. The operating device 21 is arranged on the screw side and is connected via a bore 23 to a linear movement unit, for example a pneumatic piston (not shown). Toward the milling tool, the actuating device 21 has at least one spring-loaded screw 35 which acts on the housing 11 and has at least one radially deep rolling element 36 which acts on the pressure ring 9. The pressure ring 9 has a continuous rolling surface running around in the contact region of at least one rolling element 36. In the machining state, there is no contact (clearance) between the operating device 21 and the milling tool, so that the milling tool can be driven rotationally.

To perform the profile change, the rotating milling tool is first stopped. The profile transformation can be divided into four stages.

In phase 1, the housing 11 is first moved by the disengaging movement of the operating device 21 via the spring-loaded bolt against the force of the

springs

26, 27 toward the machining side a. The housing 11 carries the two axially

movable working tools

2, 3 via its end faces until they abut against the fixed working tool 1, so that the

cylindrical pins

37, 38 come out of the contact region with the cam disk 7 and there is no longer contact between the back flat surface 39 and the basic body 4. The total spring force of the spring-loaded bolt 35 must therefore be greater than the total spring force of the

springs

26, 27. In this state, the cam disc 7 is relieved of load, whereby the friction in its subsequent rotational movement is reduced. During this stage, the spring-loaded bolt 35 is not compressed.

In phase 2, the rolling elements 36 press against the rolling surface of the pressure ring 9 and move the pressure ring in the axial direction as well towards the machining side a. The spring-loaded bolt 35 yields in this case. Since the housing 11 is locked in a rotationally fixed manner via the contact with the spring-loaded bolt 35 and the housing 11 is coupled in a rotationally fixed manner via a positive fit with the basic body 4 and the locking sleeve 5, the pressure ring 9 is forced to move rotationally when an axial pressure acts on the pressure ring 9 via the slide ring guide until the at least one ball 19 reaches the turning point of the slide ring guide on the machining side. The rotary movement of the pressure ring 9 is transmitted to the cam disk 7 via the form-

fitting elements

15, 16. The cam 17 assumes a different position relative to the

working tools

2, 3.

Phase 3 begins with the return stroke movement of the operating device 21. The rotational movement of the pressure ring 9 and the cam disk 7 is now acted upon by the spring force of the spring 28 and continues until the at least one ball 19 reaches the turning point of the slide ring on the spindle side. In this state, the pressure ring 9 is latched and the cam disk is also latched therewith.

In phase 4, the axially

movable working tools

2, 3 are moved by means of the

springs

26, 27 toward the screw side B until they, depending on the position of the cam disk 7, come to bear with their

cylindrical pins

37, 38 on the cam 17 of the cam disk 7 or with their back flat surface 39 on the basic body 4.

After the profile change is complete, the actuating device 21 is no longer in contact with the tool (clearance).

The essentially saw-toothed groove 16 of the detent sleeve 5 is designed such that the cam disk 7 is always rotated in the same direction (i.e. clockwise or counterclockwise) in progressive steps, so that after the end of an operating cycle, which consists of a release movement and a return movement (reciprocating stroke), the cam 17 of the cam disk 7 is in a changed rotational angular position relative to the working

tool

2, 3. For this purpose, the essentially saw-toothed grooves 16 (slip ring guides) of the detent sleeve 5 overlap at the turning point in the rolling direction of the balls 19, so that upon reversal of the direction of the reciprocating movement, dead points are formed and at least one ball 19 passes through the slip ring guide in one direction.

In a preferred embodiment, the inclined regions of the substantially saw-tooth shaped grooves 16 have different slopes. In this embodiment, the overlapping of the sawtooth-shaped grooves 16 is only required at the transition point from a large slope to a small slope. Advantageously, in one embodiment, the groove region facing the disengagement movement separated by the operating device 21 has a greater slope than the groove region facing the return movement initiated by the spring 28. The different slopes enable the frictional resistance to be adapted to the different forces during the release and return stroke movements and reduce the wear of the slip ring. Particularly advantageous is an embodiment in which the slope of the steeply running use region decreases progressively in the direction of movement of the ball 19. By means of such a groove curve, the force impact at the sudden start of the slip ring movement can be reduced and wear on the slip ring guide can be minimized.

The division of the slip ring guide and the cams or

cylindrical pins

37, 38 is expediently coordinated with one another such that after each operating cycle another tool is brought into the working position. Due to the pretensioning by the spring 28 and the zigzag course of the groove 16, the device snaps into a new position after each switching cycle (change of section).

The pressure ring 9 changes its angular position relative to the housing 11 after each switching process. Since each angular position can be unambiguously associated with a

tool cross-section

31, 32, 33, the angular position of the pressure ring 9 relative to the housing 11 can be used to indicate the respective

effective tool cross-section

31, 32, 33 on the screw side B of the milling tool by: for example, an index mark 43 is provided on the housing 11 and different marks 42 for

different tool sections

31, 32, 33 are provided on the pressure ring 9, so that the section marks lying opposite the index mark always indicate the

effective tool sections

31, 32, 33 (principle "chronograph disk"). The identifiability of the

effective cross sections

31, 32, 33 is necessary in particular for reference control when first put into use or after a disturbance. The marking 42 arranged on the screw side is clearly visible on the operator side, whereas the

tool sections

31, 32, 33 are normally not accessible, since they are concealed by the suction hood.

Switching cycle of section conversion:

the working tool 1 is in the working position

Resetting the working

tools

2 and 3

For the first time, switching by axial pressing of the operating device 21

The working tool 2 is in the working position

The working tool 2 is moved, 3 is reset for a second time, and is switched by pressing the operating device 21 axially

The working tool 3 is in the working position

Moving, 2-resetting the working tool 3

Thirdly, by axial pressing of the operating means 21

The working tool 1 is returned to the working position

List of reference numerals

1 first processing tool (fixed)

2 second machining tool (axial movable)

3 third processing tool (axial movable)

4 basic body

5 locking sleeve

6 spring

7 cam disc

8 axial bearing

9 pressure ring

10 safety ring

11 casing

12 screw

13 Ring

14 safety ring

15 bulge

16 grooves

17 cam

18 groove (slip ring)

19 sphere

20 flat head screw

21 operating device

22 carrier

23 fixing hole

24 screw hole (for flat head screw)

25 holes (for butt flat head screw joint)

26 spring

27 spring

28 spring

29 screw

30 flange region

31 first sensor element

32 second tool section

33 base single cutter section

34 flat head screw

35 bolts (pressure elements) acted by springs

36 rolling element (ball roller)

37 cylindrical pin

37.1 holes

38 cylindrical pin

38.1 holes

39 flat rest surface

40 flat head screw

41 rolling surface

42 marks for indicating the cross-section of the tool

43 marking for indicating the cross-section of a tool

44 groove

A side of working

Side of screw B

D axis of rotation.

Claims

1. A milling tool for machining wood, wood material, synthetic material or light metal, having a machining side (A) and a spindle side (B) and having a fixed first machining tool (1) and a second machining tool (2, 3) which are arranged in a housing (11) which is rotatable about an axis of rotation (D) and which are arranged coaxially with respect to the first machining tool (1) so as to be movable between a rest position and a machining position,

it is characterized in that the preparation method is characterized in that,

at least the second working tool (2, 3) can be connected to a cam disk (7) which is arranged rotatably in the housing (11) about a rotational axis (D) in order to be moved in the axial direction;

at least two second machining tools (2, 3) which are arranged in a movable manner are arranged between a rest position and a machining position.

2. The milling tool of claim 1,

it is characterized in that the preparation method is characterized in that,

the cam disk (7) is rotatable in steps.

3. The milling tool of claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the first machining tool (1) is rigidly connected to a base body (4) which is connected to the housing (11) in a rotationally fixed manner.

4. The milling tool of claim 3,

it is characterized in that the preparation method is characterized in that,

the cam disk (7) is connected to a sleeve-shaped pressure ring (9) which has at least one radially inwardly projecting ball (19) as a sliding ring mechanism, which runs in a meandering circumferential groove (18) of a locking sleeve (5) as a sliding ring, which is connected in a rotationally fixed manner to the housing (11), wherein the inner diameter of the pressure ring (9) is greater than the outer diameter of the locking sleeve (5).

5. The milling tool of claim 4,

it is characterized in that the preparation method is characterized in that,

the balls (19) are arranged with play in the inner wall of the pressure ring (9).

6. The milling tool of claim 4 or 5,

it is characterized in that the preparation method is characterized in that,

the meanders of the meander-shaped circumferential groove (18) run at an acute angle, wherein at least one of the spheres (19) can be guided only in a clockwise or only in a counterclockwise direction.

7. The milling tool of any one of claims 4 to 5,

it is characterized in that the preparation method is characterized in that,

the cam disk (7) is connected to the pressure ring (9) in a rotationally fixed and axially displaceable manner.

8. The milling tool of any one of claims 4 to 5,

it is characterized in that the preparation method is characterized in that,

at least one pressure spring (28) acting in the axial direction is arranged between the pressure ring (9) and the basic body (4).

9. The milling tool of claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

each second machining tool (2, 3) which is arranged in a displaceable manner has cylindrical pins (37, 38) which are arranged at regular intervals on a partial circle and which extend parallel to the axis of rotation (D) and can be brought into operative connection with cams (17) which are arranged on the cam disk (7).

10. The milling tool of claim 8,

it is characterized in that the preparation method is characterized in that,

the at least one pressure spring (28) is axially guided in the spring ring (6) and the spring ring (6) is mounted so as to be rotatable relative to the pressure ring (9) via an axial bearing (8).

11. The milling tool of claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

at least one pressure spring (26, 27) is arranged between the stationary first machining tool (1) and the one or more movable second machining tools (2, 3).

12. The milling tool of any one of claims 4 to 5,

it is characterized in that the preparation method is characterized in that,

the pressure ring (9) is provided with a closed-loop end face on the screw side, which serves as a rolling surface (41) for the rolling elements (36).

13. The milling tool of claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

each of the first and second machining tools (1, 2, 3) is provided with a plurality of cutters (31, 32, 33), wherein the cutters (31, 32, 33) are identically shaped at each of the first and second machining tools (1, 2, 3), but each of the first and second machining tools (1, 2, 3) has a differently shaped cutter (31, 32, 33).

14. The milling tool of claim 13,

it is characterized in that the preparation method is characterized in that,

the cross-section of the tools (31, 32, 33) corresponds to the radius or chamfer and the fixed first machining tool (1) carries the tool (1.1) with the largest radius.

15. The milling tool of claim 12,

it is characterized in that the preparation method is characterized in that,

the pressure ring (9) is provided on the screw side with markings (42) for the respective tools (31, 32, 33), which interact with markings (43) in the housing (11) and reduce the tools (31, 32, 33) in the processing position as a function of the rotational position of the pressure ring (9).

16. The milling tool according to claim 3, characterized in that the first machining tool (1) is screwed to the basic body (4).

17. The milling tool according to claim 4, characterized in that the sleeve-like pressure ring (9) has three balls (19) projecting radially inwards.

18. The milling tool according to claim 11, characterized in that three pressure springs (26, 27) are provided between the fixed first machining tool (1) and the one or more movable second machining tools (2, 3), respectively.

19. A machining apparatus with a milling tool according to one of the preceding claims and an axially movable operating device (21) with which a disengaging movement and a return stroke can be carried out, and which has at least one pressure element (35) and a rolling element (36).

20. The processing apparatus as set forth in claim 19,

it is characterized in that the preparation method is characterized in that,

the pressure element (35) is a spring-loaded bolt and the rolling element (36) is a spherical roller.

21. A method for operating a processing device according to claim 19 or 20,

it is characterized in that the preparation method is characterized in that,

during the disengaging movement of the actuating device (21), the contact between the second axially movable machining tool (2, 3) and the cam disk (7) is separated in a first step, the cam disk (7) is set in rotation in a second step by means of a zigzag-shaped recess (18) in the detent sleeve (5) and at least one ball (19) in the pressure ring (9), the rotational movement of the cam disk (7) ends in the subsequent return stroke of the actuating device (21), and the second axially movable machining tool (2, 3) again bears against the cam disk (7) at the end of the return stroke in a third step.