EP1896208A1

EP1896208A1 - Tool

Info

Publication number: EP1896208A1
Application number: EP06754412A
Authority: EP
Inventors: Dieter Kress; Friedrich Häberle
Original assignee: Mapal Fabrik fuer Praezisionswerkzeuge Dr Kress KG
Current assignee: Mapal Fabrik fuer Praezisionswerkzeuge Dr Kress KG
Priority date: 2005-06-20
Filing date: 2006-06-16
Publication date: 2008-03-12
Also published as: WO2006136340A1; WO2006136340A8

Abstract

A tool is proposed having a tool shank (3) and a tool head (5) which can be fastened thereto and a clamping device (11) which connects the tool shank (3) and the tool head (5) to one another and which comprises a tie rod (13), running in the longitudinal direction of the tool (1) and having a clamping head (17), and an eccentric (19) which interacts with said tie rod (13), is arranged perpendicularly to the longitudinal direction of the tool (1) and has a recess (21) in which the clamping head (17) engages in a first functional position. Said tool is characterized in that the tie rod (13) remains in the tool shank (3) when the tool head (5) is removed, in that the tie rod has a coupling device via which it can be connected to the tool head (5), and in that the tie rod (13) can be secured in the tool shank (3) for fastening the tool head (5).

Description

Tool

description

The invention relates to a tool with a tool shank and a tool head fastened thereto according to the preamble of claim 1.

Tools of the type mentioned here are known. They are characterized by the fact that the tool head are interchangeable in case of damage or wear or for the realization of different types of workpieces. For fixing the tool head on the tool shank a clamping device is provided, which has a tie rod. This cooperates with an eccentric in the tool shank and is axially displaced during a rotation of the eccentric, that is in the direction of the longitudinal axis of the tool. As a result, a tension between the tool head and shaft can be realized.

There are also known tools in which the tie rod has a relative to the longitudinal axis of the tool inclined clamping surface which cooperates with a vertically acting on the clamping surface clamping screw. When tightening this screw acting clamping forces are built up in the longitudinal direction of the tool, which clamp the tool shank am -kopf. This clamping method is complex and costly.

The object of the invention is therefore to provide a tool having a tool shank and tool head, which are connected to one another in a simple manner and can be positioned relative to one another in a specific rotational position.

To solve this problem, a tool is proposed which has the features mentioned in claim 1. The tool has for connecting the tool shank and the tool head on a clamping device which comprises a running in the longitudinal direction of the tool tie rod and an interacting with this, arranged substantially perpendicular to the longitudinal direction of the tool eccentric. This is provided with a recess into which a clamping head of the tie rod engages in a first functional position. The inner surface of the eccentric is designed so that upon rotation in a first direction, the clamping head is drawn into the interior of the eccentric and thus the tool head is clamped to the tool shank. The tool is characterized in that the tie rod is housed in the tool shank and in this is movable back and forth over a limited path in the direction of the longitudinal axis. It has a coupling device, via which it can be connected to the tool head. It can be provided here a thread or a bayonet lock. To attach the tool head to the tie rod this can be set in the tool shank, so that a rotational movement is prevented. In this way, the tool head can be attached to the tie rod without additional tools.

In a preferred embodiment of the tool is provided that the eccentric on its peripheral surface has a support surface against which the end face of the clamping head. In this case, the support surface is arranged so that in this case the tool head is arranged at a defined distance from the tool shaft and thus a torque transmission device is inactive, which otherwise prevents a relative rotation between the tool head and tool shank. In this arrangement, the tie rod is not rotatable relative to the tool shaft, so that the attachment of the tool head to the tie rod can be done easily. Further embodiments emerge from the remaining subclaims.

The invention will be explained in more detail below with reference to the drawing. Show it:

1 shows a longitudinal section through a tool with a tool shank and a tool head in a clamped state;

FIG. 2 shows a high magnification of an eccentric of the tool according to FIG. 1;

3 shows a tool according to Figure 1 in exploded view and

FIG. 4 shows a strong enlargement of the eccentric of the tool according to FIG. 3.

From a longitudinal sectional illustration according to FIG. 1, a tool 1 can be seen, which has a tool shaft 3, also referred to as a tool holder, and a tool head 5. In the area of contact between the tool shank 3 and the tool head 5, a torque transmission device 7 can be seen, which serves to transmit a torque introduced into the tool shank 3 to the tool head 5. It is generally known to provide at least one pin, also referred to as a driver, in the area of contact between the tool shank 3 and the tool head 5, which prevents a relative rotation between the two parts of the tool 1. In the exemplary embodiment illustrated here, it is provided that elevations and depressions are provided on the side of the tool shank 3 facing the tool head 5. Accordingly, elevations and depressions are likewise provided on the side of the tool head 5 facing the tool shank 3. These run radially to a longitudinal axis 9 of the Tool 1 and are formed so that they engage in the assembled state of the tool 1, as shown in Figure 1, each other. In this case, a Hirth toothing is formed, which, unlike a driver pin, allows the tool head 5 and tool shank 3 to be joined together in different rotational positions relative to one another and aligns the parts with each other at certain angles of rotation. The end faces are designed to be complementary, so that the elevations and depressions of one side can engage in that of the other side in order to transmit a torque. All you have to do is divide them. A similar design of the elevations and depressions is ultimately not mandatory, but usually provided. Thus, a Hirth toothing is realized here in order to be able to transmit torques across the interface.

The tool 1 is provided with a clamping device 11, which serves to clamp the tool shank 3 and the tool head 5 together. It has a running in the longitudinal direction of the tool 1 tie rod 13 which engages with its one end 15 in the tool head 5 and which is provided at its lower end with a clamping head 17. It also has an eccentric 19 which is arranged substantially perpendicular to the longitudinal axis 9 of the tool 1 and comprises a recess 21 into which the clamping head 17 can be introduced via an insertion opening 23. A wall 25 which surrounds the recess 21 in certain areas grips the clamping head 17 in a first functional position and pulls it into the recess 21 during a rotation of the eccentric 19 in a first direction of rotation, in this case in a clockwise direction, so that the tie rod 13 moves in the direction the longitudinal axis 9 is displaced downwards. As a result, the tool head 5 is tightened on the tool shank 3. The clamping head 17 of the tie rod 13 has a larger outer diameter than this and is arranged in a first region 27 of a cavity 29 in the tool shank 3. The tie rod 13 is housed in a second region 31 of the cavity 29, whose outer diameter is smaller than that of the first region, so that the tie rod 13 can not be pulled out of the cavity 29 forward in the direction of the tool head 5.

The outer diameter of the eccentric 19 is greater than that of the first region 27, so that the eccentric, which is also fixed in the surrounding the cavity 29 of the tool shank 3 wall, in the axial direction, that is, in the direction of the longitudinal axis 9, not displaced is.

The eccentric 19 prevents the tie rod 13 from falling out of the interior of the tool shank 3 - in FIG. 1 downwards. This is thus only about a certain way in the direction of the longitudinal axis 9 of the tool 1 back and forth movable. Incidentally, it is arranged concentrically to the longitudinal axis 9. The eccentric 19 is introduced into the tool 1 such that its central axis intersects the longitudinal axis 9 perpendicularly.

The outer contour of the tool shaft 3 is formed here on the side facing away from the tool head 5 substantially cylindrical in order to use the tool shank 3 in a suitable holder can. It is quite possible to adapt the shape of the tool shank 3 to different holding systems and / or to provide it with an outer cone in the end region facing away from the tool head 5.

From Figure 1 it can be seen that the tool head 5 is provided with a blind hole 33 which extends from below into the tool head 5, so that the front side of the tie rod 13 receiving recess is not cut. This allows a largely free design of the tool head. 5

In the exemplary embodiment illustrated in FIG. 1, the tool head 5 is provided with at least one, here with two coolant / lubricant channels 37, 39, which for example run parallel to the longitudinal axis 9 and open into the front side 35 of the tool head 5. However, it is possible to provide at an angle to the longitudinal axis 9 extending channels, which open into the lateral surface 41 of the tool head 5.

For reasons of simplification, FIG. 1 does not show that the at least one, here the two coolant channels 37, 39, continue in the main body of the tool shank 3.

In the embodiment shown in Figure 1, the diameter of the tool head 5 is selected so that it coincides with the diameter of the tool shank 3 at least in the adjacent area. Thus, the lateral surface 41 of the tool head 5 is in the peripheral surface 43 of the tool shank 3 via. Preferably, the diameter of the tool head 5 is slightly larger than that of the tool shank 3.

For the function of the tool 1, however, this aspect is not essential for all applications.

It can be seen from the illustration according to FIG. 1 that the eccentric 19 is rotated into a position in which the insertion opening 23 points to the right and the wall 25 comprises the tie rod 13. The eccentric 19 is here to the right, that is rotated in a clockwise direction, so that the clamping head 17 is displaced downwards by a maximum distance and the tool head 5 firmly clamped on the tool shank 3. Figure 2 shows a section of the tool 1 according to Figure 1. The same parts are provided with the same reference numerals, so that reference is made to the preceding description. The illustration shows the tool 1 in longitudinal section, namely the area in which the eccentric 19 is introduced. This is compared to the illustration in Figure 1 to the left, ie counterclockwise, so twisted that the wall 25 no longer comprises the clamping head 17 on the side facing the tool head 5, not shown here. Rather, the insertion opening 23 of the eccentric 19 upwards, ie in the direction of the tool head 5, directed, so that the clamping head 17 is inserted into the recess 21 in the interior of the eccentric 19. The clamping head 17 is at a distance to an ejection surface 45, which will be discussed in more detail below and which extends approximately horizontally here.

When the chuck 17 is inserted into the recess 21, the eccentric 19 can be rotated clockwise. In this case, the inner surface 47 of the wall 25 slides along the curved surface of the clamping head 17. The outer surface of the eccentric 19 is cylindrical. The thickness of the wall 25 increases counterclockwise from the insertion opening 23, so that the clamping head 17 is displaced downwards along the longitudinal axis 9 in the direction of the ejection surface and the tool head 5 is clamped on the tool shank 3.

It turns out here that the initial position of the clamping head 17 must be very accurately predetermined, because the clamping path of the eccentric 9 is relatively small. If the clamping head 17 is too high in its initial position, it prevents a rotational movement of the eccentric 19 in a clockwise direction. If the tool head 5 and the tool shank 3 are not practically completely continuous with one another, then the clamping travel given in the clockwise direction when the eccentric cam 19 is rotated is not sufficient to realize a precisely defined clamping between the tool shank 3 and the tool head 5. It is therefore extremely important that the clamping head 17 - as seen in the axial direction, ie in the direction of the central axis 9 - is aligned exactly opposite the tool head 5 in order to realize a defined clamping of the two parts of the tool 1.

The rotational movement of the eccentric 19 is limited. It is clear that a first boundary surface 51 of the recess 21 abuts on the clamping head 17 when the eccentric 19 is rotated further from the position shown in Figure 2 to the left counterclockwise.

It is also clear from the representation according to FIG. 2 that a second boundary surface 53, which can also be seen in FIG. 1, limits the rotational movement of the eccentric 19 to the right in the clockwise direction. In the illustration according to FIG. 1, the second boundary surface 53, which is not provided there with a reference number, adjoins the clamping head 17, so that a rotational movement to the right beyond the position shown in FIG. 1 is not possible.

FIG. 3 shows the tool according to FIG. 1 in an exploded view. The same parts are provided with the same reference numerals, so that reference is made to the description of the preceding figures.

It is clear here that the eccentric 19 is in a further functional position, the second functional position: it is rotated so that the wall 25 facing upward in the direction of the tool head 5, wherein the chuck 17 of the clamping device 11 is not inside the eccentric 19 is located, so is not absorbed by the recess 21. Rather, it lies in the region of the wall 25 on its outer surface and is thus displaced in the axial direction, ie in the direction of the longitudinal axis 9, from the position shown in Figure 2 upwards. He can not by the support of the wall 25 in the direction of Longitudinal axis 9 are moved down. Thus, the upper end 15 of the tie rods 13 further projects upward beyond the upper side of the tool shank 3, as is the case in the illustration according to FIG. There is therefore the possibility in this functional position of the eccentric 19 to fasten the tool head 5 at the upper end 15 of the tie rod 13. In this case, the coupling between the tool head 3 and tie rod 13 can be produced by a bayonet lock, but preferably by a threaded connection. For this purpose, the blind hole 33 is at least partially provided with an internal thread which cooperates with an external thread at the upper end 15 of the tie rod 13.

The tie rod 13 is so far pushed out of the tool shank 3 due to the functional position of the eccentric 19 shown here that the tool head 5 can be screwed easily at the upper end 15. In this case, the distance to the tool shank 3 is so great even in the screwed state of the tool head 5 that the torque transmission device 7 is not yet effective. The tool head 5 is thus freely rotatable relative to the tool shank 3.

The tie rod 13 is, as explained above, mounted on a limited path in the direction of the longitudinal axis 9 movable in the tool shaft 3. For attachment of the tool head 9 at the upper end 15 of the tie rod 13, it is necessary to set it during the fastening operation so that it is not freely rotatable when unscrewing and screwing the tool head 5.

The rotationally secure fixation of the tie rod 13 in the tool shank 3 can, for example, take place in that the tie rod 13 is provided with a transverse bore into which a pin can be inserted. At this the tie rod 13 can be held while the tool head 5 is screwed. It is also possible At least in the region of the tie rod 13, which protrudes in Figure 3 on the front of the tool shank 13, at least provide a key surface on which the tie rod 13 can be rotatably held. Finally, it would also be conceivable to fix the tie rod 13 in the region projecting beyond the front side of the tool shank 3 with a clamping tool, while the tool head 5 is unscrewed or screwed tight.

It is therefore to be noted that the tie rod 13 is mounted in the tool shank 3 in such a way that it is mounted so as to be movable back and forth relative to it along a limited distance of movement in the direction of the longitudinal axis 9 of the tool shank 3. In this case, the movement is limited according to Figure 1 upwards in that the second portion 31 of the cavity 29 in the tool shank 3 has such a small inner diameter that the clamping head 17 can not pass. In the opposite direction, in Figure 1 down, a chaffing of the tie rod 13 from the cavity 29 in the tool shank 3 is excluded by the fact that here the eccentric 19 is provided. The mobility of the tie rod 13 can be exploited to ensure an anti-rotation only in a certain position in the direction of the longitudinal axis 9 of the tool shaft 3.

This can be done, for example, that the tie rod 13 has on its outer surface at least one projection which engages in a recess on the inside of the cavity 29 when the tie rod 13 has been displaced upwards, so that its end protrudes from the tool shaft, that there the tool head 5 can be attached. Due to the interaction between the projection and recess of the tie rod 13 is held against rotation, so that the tool head 5 can be screwed onto the tie rod 3.

If the tie rod 13 is moved downwards after screwing the tool head to the tool head 5 and the tool shank 3 to assemble in the contact area, it requires no rotation of the tie rod 13 in the tool shaft 3 more. It is therefore conceivable that with a displacement of the tie rod 13 down the projection of the tie rod is no longer engaged in the associated recess in the tool shank 3.

It should also be noted that a reverse realization is possible: It can be provided a projection on the tool shank which engages only in a certain position in a recess of the tie rod 13.

FIG. 3 shows that a step S is formed at the transition between the first region 31 with the smaller inner diameter and the second region 29 with the larger inner diameter. If a corresponding shoulder is provided on the tie rod 13, an anti-twist can be realized by the interaction between the step and the shoulder, for example the fact that here at least one pin on the shoulder in a recess on the stage or a pin on the stage in a recess engages the shoulder. Other form-locking anti-rotation can be realized by the interaction between level and shoulder. For example, projections and recesses and a Hirth toothing could be provided.

An embodiment is preferred in which a polygonal-shaped region PZ is formed in a first region of the outer surface of the tie rod in the immediate vicinity of the clamping head 17, which engages in a polygonal section PA which is formed in the first region 31. This engagement takes place only when the tie rod 13 rests on the outer surface of the eccentric 19 and thus to the front, or according to Figure 1 upwards, is displaced, so that the tool head 5 can be screwed onto the end of the tie rod 13. Also in this case, the tie rod 13 is supported against rotation in the tool shaft 3 only when it is in the position in which a tool head 5 can be screwed.

The rotation between the tie rod 13 and tool shank 3 can be realized in many other ways. Thus, the tie rod 13 may be partially realized as a flat material, which is guided in a slot in the tool shaft 3.

Accordingly, it is also possible to form the tie rod 13 partially oval and to guide through an oval recess in the tool shank 3, so that a rotation of the tie rod 13 relative to the tool shank 3 is prevented.

It is also conceivable to provide either on the tie rod 13 or on the inner surface in the first region 31 a groove in which a corresponding projection is provided on the opposite surface, which is guided in the groove.

It is essential in any case that the tie rod 13 is held against rotation at least in the position in the tool shank 3, in which on the eccentric 17 opposite end of a tool head 5 can be screwed or fastened in any other way.

The tie rod 13 is displaceable in the direction of its longitudinal axis, thus also in the direction of the longitudinal axis 9 of the tool 1 and the tool shaft 3. This is provided with a cavity 29 having two areas. The first region 27 has an inner diameter which is chosen so large that the clamping head 17 of the tie rod 13 is displaceable in this first region. The outer diameter of the clamping head is thus smaller than the inner diameter of the first region 27. From the figures it can be seen that the cavity 29 has a second region 31 which adjoins the first region 27 and the extends to the end of the tool shank 3, to which the tool head 5 is attached. This second region 31 has a smaller inner diameter than the first region 27, wherein the inner diameter of the second region 31 is greater than the outer diameter of the tie rod and smaller than the outer diameter of the clamping head 17. Therefore, a shoulder S is formed, against which the clamping head 17 abuts when it is pulled forward in the direction of the tool head 5 from the tool shank 3.

At a distance from this shoulder S of the eccentric 19 is introduced into the tool shank 3, which extends transversely to the cavity 29 and thus closes it.

The tie rod 13 can thus move forward in the direction of the tool head 5 until the clamping head 17 abuts the diameter taper, ie the shoulder S, between the first region 27 and the second region 31 of the cavity 29. In the opposite direction, the movement path of the tie rod 13 is limited by the fact that the clamping head 17 abuts against the outer wall of the eccentric 19 when it is rotated so that its insertion opening 23 is not aligned with the longitudinal axis 9 of the tool shaft 3.

On the outside of the tie rod 13, a polygonal PZ is formed, which can cooperate with a polygonal portion PA of the inner wall of the second portion 31 of the cavity 29, so that the tie rod 13 is rotatably held.

The polygonal region PZ of the tie rod 13 can connect directly to the clamping head 17 or only begin at a distance to this. It extends in the longitudinal direction of the tie rod 13 in the direction of the tool head 5 facing the end of the tool shaft 3 so far, that it engages with the polygonal portion PA of the second portion 31 when the tie rod 13 is fully withdrawn from the tool shank 3, so that the chuck 17 at the shoulder between the first portion 27 and the second portion 31 of the cavity 29th is applied. He can, starting from the chuck 17 extend as far upwards in the direction of the tool head 5, that he then cooperates with the polygonal portion PA in the second region 31 when the chuck 17 is pushed inwardly into the tool shank 3 and on the contact surface 57 (see Figure 4) of the eccentric 19 rests.

However, the polygonal region PZ of the tie rod 13 is so close to the chuck 17 that it no longer engages with a polygonal portion PA on the inner surface of the second region 31 when the tie rod 13 down, that is, in the direction of the eccentric 19th , is displaced while the clamping head 17 enters the interior of the eccentric 19, ie in the recess 21 and thus assumes the reproduced in Figure 2 position.

Thus, if the tie rod 13 with its chucking head 17 rests on the contact surface 57 of the eccentric 19 or if it is pulled further out of the tool shank 3, an anti-rotation device is provided by the polygonal region PZ of the outer surface of the tie rod and the polygonal section PA of the inner surface of the second region 31 guaranteed.

But moves the tie rod 13 further in the direction of the eccentric, because it has been rotated so that the clamping head 17 can enter through the insertion opening 23 in the recess 21 of the eccentric 19, the polygonal area PZ of the tie rod no longer engages in the polygonal Section PA of the first region 31, so that the tie rod is rotatable. This results in the following basic principle:

The tie rod 13 can be pulled so far out of the tool shank 3, that it is secured against rotation. In this position, the tool head 5 can be easily attached to the tie rod 13, preferably screwed, because the tool head 5 facing the end of the tool shank 3 and the tool shank 3 facing the end of the tool head 5 does not yet engage with each other. If now the tool head 5 is brought closer to the tool shank 3 and indeed just so far that the torque transmission device 7 does not yet take effect, the rotation lock of the tie rod 13 in the tool shank 3 is released, so that the tie rod 13 and thus also the tool head 5 with respect to the tool shank 3 is freely rotatable. It is now possible to rotate the tool head 5 in the desired manner relative to the tool shank 3 and to ensure a defined relative position of the two parts. For example, it can be achieved that coolant / lubricant additives in the tool shank 3 are aligned with corresponding channels in the tool head 5.

This basic principle of the rotation of the tie rod 13 in the tool shaft 3 on the one hand and the free rotation of the tie rod 13 in the tool shaft 3 to align the tool head 5 relative to the tool shaft 3 can be realized in various ways, namely by the at least one projection on the outer surface of the tie rod 13 and a corresponding recess on the inside of the second region 31 of the cavity 29 or by the here described partially provided polygonal configuration of a portion of the outer surface of the tie rod and the corresponding complementary configuration of a portion of the inner surface of the second portion 31 of the cavity 29th In view of the small clamping travel of the eccentric 19, it is very important that the coupling between the tool head 5 and the upper end 15 of the drawbar 13 is specially designed: exact positioning of the tool head 5 with respect to the upper end 15 of the pull rod 13 must be achieved the tool head 5 is firmly anchored to the pull rod 13. For this purpose, a contact shoulder AS is provided in the transition region between the external thread at the upper end 15 and the remaining tie rod 13. This can be realized in that the outer diameter of the tie rod 13 in the region of the upper end 15 is slightly smaller than in the adjoining area below.

The stop shoulder AS interacts with a stop surface AF of the tool head 5, which is formed by an annular surface in the tool head 5. The stop shoulder AS is firmly against the stop surface AF, when the tool head 5 attached to the tie rod 13, preferably screwed, is. This results in an exact positioning of the tool head 5 relative to the pull rod 13 and thus relative to the chuck 17. If the tool head 5 is placed on the tool shank 3 after a rotation of the eccentric in its receiving position according to FIG 2, the chuck 17 is located in the recess 21st the eccentric 19 so that the wall 25 does not abut against the side surface and a rotational movement of the eccentric 19 is prevented.

In an exact positioning of the clamping head 17 in the recess 21 of the eccentric 19 after placing the tool head 5 is rotatable so that the clamping head 17 displaces axially downwards and the tool head 5 is clamped on the tool shank 3.

In Figure 4, the eccentric is shown enlarged in the position shown in Figure 3. Same parts are the same Reference numerals, so that reference is made in this respect to the description in the preceding figures.

From the enlargement, it is clear that the clamping head 17 has a bearing surface 55 which rests on the peripheral surface 57 of the eccentric 19. As a result, the tie rod 13 is held in a position displaced upward in accordance with FIG. 1. At least in this position, it is advantageous if a relative rotation between the clamping head 17 and thus the tie rod 13 relative to the tool shank 3 is avoided. In this way, therefore, the tie rod 13 is rotatably held in the tool shaft 3. At the same time, therefore, the clamping head 17 relative to the position shown in Figure 2 in the direction of the longitudinal axis 9 is displaced upward, so that the tie rod 13 is moved and the tool head 5 attached to the end of the tie rod 13, in particular screwed, can be.

The function of the tool 1, which was explained with reference to FIGS. 1 to 4, will be explained in more detail below:

The tool 1 thus consists of two parts which can be clamped together by means of a clamping device 11 rotatably. For the rotationally fixed anchoring of a tool head 5 on a tool shank 3 is a

Torque transmission device 7 is provided, which is formed for example as a Hirth toothing. In the clamped state shown in Figure 1, the eccentric 19 detects the clamping head 17 of a tie rod 13 and pulls it by means of the wall 25 in Figure 1 in the direction of the longitudinal axis 9 downwards. The eccentric 19 is shown in Figure 1 in its cocked position, wherein the rotation in the clamping direction, ie in a clockwise direction, is limited by the second boundary surface 53.

To release the connection of the tool head 5 and tool shank 3 of the eccentric 19 is opposite to Turned clockwise to the left. It can be rotated about the position shown in Figure 2 still something until the first boundary surface 51 abuts the chuck 17. In this case, the chuck 17 is displaced by tilting the ejection surface 45 in the axial direction, ie in the direction of the central axis 9, upwards, so that the connection between the tool shank 3 and the tool head 5 is released and the two parts are taken apart.

The tie rod 13 is movable in the axial direction over a limited way. At the top, the movement is limited by the fact that the second region 31 of the cavity 29 in the tool shank 3 has an inner diameter which is smaller than the outer diameter of the chuck 17. Downwards, the movement of the tie rod 13 is effected by the eccentric 19 inserted in the tool shank 3 limited.

After releasing the connection between the tool shank 3 and the tool head 5, the tool head can be pulled upwards, so that the chucking head 17 is moved out of the recess 21. Subsequently, the eccentric 19 can be rotated clockwise relative to the position shown in Figure 2 to the right, so that the clamping head 17 can no longer get into the insertion opening 23 of the eccentric 19 and into the recess 21, but rather on the peripheral surface 57 of the eccentric 19th rests. In this case, the contact surface 55 of the clamping head 17 rests on the circumferential surface 57. In this position, the rotation between the tie rod 13 and the tool shaft 3 can be activated. As a result, the clamping head 17 and thus the tie rod 13 rotatably held in the tool shaft 3. It is now possible to detach the tool head 5 from the upper end 15 of the tie rod 13 or to attach to this. The rotation can also be designed so that a relative rotation of the tool parts to each other only at a further withdrawal of the tie rod 13 from the tool shaft 3 is possible.

Since the drawbar 13 can be designed to be relatively thin, the embodiment of the tool 1 described here can also be used for tools with a very small diameter.

Incidentally, the configuration of both the tool shank 3 and the tool head 5 is freely selectable, so that drills, cutters and / or reamers can be realized.

If, as described above, a blind hole 33 is introduced into the tool head 5, then the end face of the tool head 5 can be used, since cutting can also be provided here. It is thus possible to realize drills with at least one center cutting edge with which holes can then be drilled into the solid.

Also, the tool shaft 3 is, as indicated above, freely ausgestaltbar. It can therefore be combined directly with a machine tool, with adapters, spacers or the like.

Finally, it should be noted that intermediate elements can also be introduced between the tool head 5 and the tool shank 3, which then have torque transmission devices on both sides. In this case, then the length of the tie rod 13 must be matched to the design of the tool.

Claims

claims

1. tool with

a tool shaft (3) and an attachable tool head (5),

a torque transmission device (7) provided in the area of contact of the tool shaft (3) and the tool head (5),

- A the tool shank (3) and the tool head (5) interconnecting clamping device (11) extending in the longitudinal direction of the tool (1), a clamping head (17) having tie rods (13) and cooperating with this, perpendicular to the longitudinal direction of the tool (1) arranged eccentric (19) with a recess (21), in which the clamping head (17) engages in a first functional position,

characterized in that the tie rod (13) is mounted in the tool shank (3) so as to be reciprocated relative thereto along a limited distance of movement in the direction of the longitudinal axis (9) of the tool shank (3), that the tie rod (13 remains during disassembly of the tool head (5) in the tool shank (3) that the tie rod has a coupling device, via which it is connectable to the tool head (5), and that the tie rod (13) for fixing the tool head (5) in Tool shank (3) can be fixed.

2. Tool according to claim 1, characterized in that the tie rod (13) has on its outer side at least one projection and / or a recess which cooperates with a recess and / or a projection on the tool shank (3).

3. Tool according to claim 1 or 2, characterized in that the tie rod (13) has at least one polygonal outer side region which cooperates with at least one polygonal inner surface portion in the tool shank (3).

4. Tool according to one of the preceding claims, characterized in that the peripheral surface (57) of the eccentric (19) is designed as a support surface on which the end face of the clamping head (17) rests, so that the tool head (5) at a defined distance arranged to the tool shank (3) and the torque transmission device (7) is inactive and the tool head (5) relative to the tool shank (3) rotatably and on the clamping head (17) facing away from the end of the tie rod (13) is attachable.

5. Tool according to one of the preceding claims, characterized in that the tie rod (13) an abutment shoulder (AS) and the tool head (5) has a stop surface (AF), so that at a connection between the tool head (5) and tie rod (13 ) A defined axial arrangement of the tool head (5) relative to the clamping head (17) can be predetermined.

6. Tool according to one of the preceding claims, characterized in that the tool head (5) has a the upper end (15) of the tie rod (13) receiving blind hole (33).

7. Tool according to one of the preceding claims, characterized in that the tool head (5) has on its the tool shank (3) facing side substantially radially extending elevations and depressions, and that the tool shank (3) on its the tool head (5) facing side substantially radially extending elevations and depressions, that the elevations and depressions of the two parts in the assembled state of the tool (1) interlock and form the torque transmission device (7).

8. Tool according to one of the preceding claims, characterized in that the tool head (5) and / or the tool shank (3) has / have at least one coolant / lubricant channel.

9. Tool according to one of the preceding claims, characterized in that the tool head (5) is designed as a drill head, cutter or reamer.

10. Tool according to claim 9, characterized in that the drill head has at least one center cutting edge.