GB2171619A - Cutting tool with a replaceable tip - Google Patents

Abstract

A cutting tool with a replaceable cutting tip is fastened on a prismatic cutting tip holder (110) which is adjustably fastened to the tool body (11). The tool body has a slot (111) formed from two surfaces running at an angle to one another, and the cutting tip holder is penetrated, with play, by a clamping screw which extends equally inclined to the two surfaces and by which the cutting tip holder can be pressed flat against the one slot surface and, by two adjustable eccentric rod-like support elements (200), against the other slot surface (112). Adjustment of the cutting tip holder or several cutting tip holders in relation to one another can be performed by rotation of the elements (200). <IMAGE>

Description

SPECIFICATION Cutting tool with a replaceable tip Background of the invention The invention relates to a cutting tool with a replaceable tip.

A cutting tool is known from DE-OS 2505515 which has a replaceable cutting tip which is mounted in a prismatic cutting tip holder which is inserted in a correspondingly shaped slot in the cutting tool body.

The holder can be fastened on the tool body by a clamping screw which so penetrates the cutting tip holder that the holder is pressed flat against a first slot surface and at the same time in the direction of a second slot surface running at an angle thereto.

Fastening of the cutting tip holder is achieved by a central clamping screw, whereby the fixing of position is performed by the lateral faces of the cutting tip itself, which can be brought into bearing contact with the bearing surface of the cutting tip holder. The clamping screw thus presses the cutting tip holder against the first slot surface in such a way that at the same time a centering of the cutting tip on the bearing surface can take place. This results in the fact with this known cutting tool that no adjustment of the cutting tip holder is any longer possible, since the alignment and orientation of the cutting tip is determined by the shaping of the slots and bearing surfaces of the cutting tool body.

However, since cutting tools equipped with cutting tips are very expensive there is a need to provide the cutting tool body and the cutting tip supports with more versatility. In line with this development, it was proposed to equip a universal tool body with adjustable cutting tip holders, so-called bit cartridges, whereby a kit is produced with which by a selective combination of the individual cartridges a multiplicity of special machining operations can be performed in a working cycle. Such a tool kit is described, e.g., in the journal "tz fuer Metallbearbeitung" [Technical Journal for Metalworking], number 12/81. In this known kit, the cutting tip holders are adjustably inserted in axial calibrated bores, and each cutting tip holder, for its part, carries a radially adjustable cutting support.

It has been found that in the case of modern tools, with which in a single working cycle several operating surfaces having close tolerances are to be produced, which must be positioned in relation to one another with close tolerances, it is not sufficient to simply adjust the cutting tip in the axial and radial directions respectively with respect to the translational direction of movement. What is more, it has proven desirable to provide a possibility of tilt adjustment of the cutting tip and thus of the bit cartridge, so that the clearance angle of the cutting edge to the feed direction can be determined exactly.

In this connection it is the task of the manufacturer of such special tools to provide the user with a tool in which the individual cutting tip holders are already exactly aligned with one another, so that the user merely has to clamp the tool in the corresponding machine too.

The adjustment of such tools, however, requires high-precision optical devices, as a result of which the adjustment process becomes relatively costly.

The mounting of the cutting tip holders on the tool body must therefore be so reliable that the cutting tip holders cannot be moved in shipping and use of the special tool. But, on the other hand, it must be possible to adjust the cutting tip holder with simple manipulation so that the time expended in adjustment is kept small. Known concepts for mounting of a cutting tip holder of the type described above do not sufficiently meet these requirements, so that tool manufacturers have to resort, after the first relative adjustment of the cutting tips, to protecting the bit cartridges from undesirable movement by additional safety measures, e.g., by sealing of the mounting devices used.

For the defined and reliable adjustment of the cutting tip holder or of several cutting tip holders to one another with a minimum of manipulations in German patent application P 33 27478.9 a cutting tool was proposed in which the adjustable support elements for the cutting tip holders are formed from support screws which go through the cutting tip holder in such a way that, together with the screw tips by which the support is to be achieved, they essentially project perpendicularly from the cutting tip holder surface, which is turned toward the second slot surface.

With this support of the cutting tip holder on the tool body a statically determined clamping of the cutting tip holder is achieved, whereby the single clamping screw acts on the cutting tip holder in such a way that by tightening of the clamping screw, both adjustable support screws are reliably pressed against the second slot surface. The play between the clamping screw and the slot provided for this purpose in the cutting tip holder can thus always be kept large enough that the necessary translational and rotational adjustment degrees of freedom of movement within very narrow limits are made available.The stability of the cutting tip holder is not lessened by the calibrated bore for the clamping screw, an action increasing stability is produced especially by the surface contact pressure of the cutting tip holder and the proposed adjustment of the cutting tip holder leaves open the advantageous possibility of applying the main cutting forces acting on the cutting tip by the surface contact between the cartridge and the tool body.

A cutting tool of the type described above is particularly economical if the tool body is provided with a multiplicity of cutting tip holders, so that a cutting tool so designed can, in a single operating cycle, produce a multiplicity of operating surfaces, which have closely toleranced, predetermined positions in relation to one another. In this case, the individual cutting tip holders must be mounted on the tool body, staggered radially and/or axially and/or in the peripheral direction with a minimum of space. However, the cutting tip holder adjustment proposed in German patent application P 33 27 478.9 is not always suitable for placing the individual cutting tip holders in a minimum of space.To provide a free accessibility of the individual support screws, for example, in the configuration of the cutting tool as a shank tool, adjacent cutting tip holders, whose cutting tips are in a common radial plane, must be placed axially offset by a certain space, to assure the free accessibility of the support screws. This in the end results in the fact that the cutting tool cannot always be made in a sufficiently small size, which, especially in the configuration as a shank tool, can result in an enlargement of the rotating masses and in an impairment of the dynamic cutting behavior.

Summary of the invention Therefore, the object of the invention is to develop a cutting tool in which with the smallest possible volume there is the possibility of placing a multiplicity of cutting tip holders which are freely adjustable in a minimum of space.

The invention thus provides a cutting tool with a replaceable cutting tip, which is fastened on a prismatic cutting tip holder which, for its part, can be adjustably fastened on the tool body. The tool body exhibits, for inserting the cutting tip holder, a slot formed form two surfaces running at an angle to one another, and the cutting tip holder is penetrated, with play, by a clamping screw, which extends in a clamping direction forming an essentially equally large angle with the two slot surfaces and by which the cutting tip holder can be pressed flat against the one slot surface and, by two adjustable support elements, against the other slot surface. With the described cutting tool, the adjustment of the cutting tip holder or several cutting tip holder in relation to one another can be performed exactly and reliably and at the same time with a minimum of adjustment manipulations.

According to the invention another orientation of the support elements is achieved in such a way that these support elements essentially are accessible in the cutting direction of the cutting tip. As a result, the possibility is offered of placing two cutting tip holders immediately adjacent in the same axial plane, for example, in the case of a shank tool designed as a boring or milling tool and yet assuring a free accessibility of the support elements. By suitable configuration of a countersunk head support surface for the clamping screw penetrating the cutting tip holder, the cutting tips can be positioned immediately adjacent one another even without axial offset. Thus, according to the invention an essentially enhanced flexibility results in regard to the grouping or staggering of the cutting tips on the cutting tool.The advantageous and stability-enhancing support of the cutting tip holders on the tool body is kept unchanged, so that the tool is marked by a very good dynamic cutting behavior.

In a further development, a simple form of the slots and the bit cartridges results. The particular configuration of the eccentric pin contributes not only production engineering advantages but further creates the condition for a linear support of the cutting tip holder on the second slot surface to occur in at least one place, as a result of which the stresses of the support elements and the tool support can be reduced. Since the slot and the cartridges have a very simple contourrthere is no difficulty in shaping the slot and the surface or the placing ofthe eccentric pin so exactly that a statically determined support of the cutting tip holder on the tool body can result.

Guiding of the eccentric pin can take place either in the tool body or in the respective cutting tip holder.

However, to keep the possibility open of mounting various cutting tip holders in a slot of a tool body, which in turn can be equipped with various cutting tips, whose adjustment spectrum can be quite different, it is particularly advantageous to guide the adjustment pin in the cutting tip holder itself. The cam section in this case can extend over the entire length or have only on a single location a knobshaped elevation with which it can be pressed in point or linear contact with the opposite slot surface of the tool body.

With selected dimensioning there results, on the one hand, a very good guiding of the support eccentric pin and, on the other hand, an adequate adjustment elevation.

An especially favorable force transfer between the slot surfaces and the cutting tip holder is obtained with the further development of the support eccentric pin, wherein by variation of the length of the middle region, over which the eccentric section extends, an optimal matching of the support surfaces in the cutting tip holder to the deformation behavior of the eccentric pin and friction ratios in the areas of the bearing supports can be achieved.

The construction space required by the cutting tip holder is also advantageously used for placing the eccentric section and at the same time care is taken that the eccentric region can be distributed over the entire circumference of the eccentric pin so that adjustment of the cutting tip holder can be made particularly fine, i.e., down to the lim range. It has been shown that with this design even extreme pressure forces can be transferred from the slot surfaces to the cutting tip holders by the eccentric pins, as a consequence of which there results the assembly advantage that the cutting tip holder can be prestressed by the clamping screw penetrating it before the final fine adjustment.

Since the eccentric pins must transfer only the pressure forces, for the configuration of the matching slots in the individual cutting tip holders a semicylindrical surface opening to the cutting tip holder surfaces suffices. With such a configuration of the matching slots it is advantageous for storage reasons and also for assembly reasons for the transition sections in the cutting tip holder between the slot bottom and the cutting tip holder surface to be so designed that they can be compressed toward one another. With this design, the eccentric pins inserted in the cutting tip holder can be prevented from falling out in a very simple way, i.e., with a suitable compressing tool.

Since with a suitable configuration of the eccentric pin the possibility is opened up of distributing the eccentric total elevation over a maximum angle of 1800, with an average surface roughness of the end sections of the eccentric pin and the semicylindrical surfaces receiving them an automatic locking condition results, so that additional devices for assuring the position of the eccentric pin can be omitted.

So as not only to tilt the cutting tip holder but also to be able to adjust it in the feed direction, an adjustment pin can be used in the design, whereby it is particularly advantageous to bring these adjustment eccentric pins in linear contact with the support surface. It has been found that even with this adjustment method the friction forces between the eccentric section and the support surface are so small that exact position adjustment of the cutting tip holder is not impaired or distorted by this adjustment.

The configuration of the adjustment eccentirc pin is particularly advantageous in that through it the possibility is opened up of using an outside surface of an adjacent cutting tip holder as a support surface for the adjustment eccentric pins and thus of designing the cutting tool to be even more compact.

Brief description of the drawings Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts throughout the several views and wherein:: Figure 1 is a front view of a shank milling and boring tool in the configuration of German patent P 33 27 478.9, equipped with several cutting tip cartridges; Figure 2 is a cross section view of the tool shown in Figure 1 in a section along line Il-Il in Figure 1; Figure 3 is an axial half-section through a first embodiment of the cutting tool according to the invention; Figure 4 is a view of the cutting tool according to Figure 3 in another axial section; Figure 5 is a view of detail "X" in Figure 3; Figure 6 is a perspective view on enlarged scale of an inserted support eccentric pin guided in a cutting tip holder; Figures 7 to 9 are perspective views of three other variants of the support or adjustment eccentric pin;; Figure 10 is a perspective view of a cutting tip holder for an eccentric pin according to Figure 9, and Figures 11 and 12 show two axial half-sections similar to those of Figures 3 and 4 through another embodiment of the cutting tool according to the invention.

Description of the preferred embodiments The figures show cutting tools, which are designed as part of a shank tool. The tool is identified by reference number 1 and is used for the machining of a multiplicity of operating surfaces 2 represented by dot-dash lines, which are to be machined in an operating cycle so that predetermined and closely toleranced positions in relation to one another is achieved. For this purpose, tool 1, shown in Figures 1 and 2, exhibits several cutting tip groups 3 to 5 which are mutually offset in axial and radial directions, each of which has several cutting tips inserted in separate cutting tip holders, e.g., holders 44 to 46 of cutting tip group 4 and holders 54 to 56 of cutting tip group 5.

To be able to provide the workpiece to be machined with the desired surfaces, whose positional relation to one another has very close tolerances, the respective cutting tip holders or cutting tip cartridges must be adjustably mounted on tool body 11.

For this purpose, the cutting tip holders have essentially the shape of a prism or a right parallelepiped, which in each case is inserted in a slot matching the cross section of the parallelepiped, each of which exhibits two surfaces 61, 62, 71, 72 and 81 or 82 running at an angles to one another, whereby in Figures 1 and 2 the slots of cutting tip group 4 are identified by subscript a and the slots of cutting tip group 5 by subscript b.

The angle formed by the slot surfaces of the slots matches the prismatic cross section of the cutting tip holders. The slots moreover are made so that the cutting tips in each case come to be positioned in radial planes 91 and 93. For this purpose, each cutting tip holder has on the side turned away from the cutting tips of plane surface which is in surface bearing contact with slot surface 61, 71 or 81, which runs parallel to corresponding radial plane 92, 93, or 91 and is to be referred to as the first slot surface.

The corresponding situation applies to the cutting tip holders of second cutting tip group 4.

Cutting tip holders 54 and 56 are supported by their prismatic surface adjacent to cutting tips 53 or 51 directly on the opposite slot surface 62 or 72, so that the cutting tip holders are guided in the slot in a raillike manner. Cutting tip holders 44 or 46 and cutting tip holder 55 are supported on slot surface 82 by two points, which are formed by adjustable support screws or pins 12 and 13.

For immovable mounting of individual cutting tip holder cartridges 44 to 46 or 54 to 56, they have an essentially central through-hole l6forinserting a relatively solid clamping screw 17, for which a threaded hole 18 is provided in each case in tool body 11. Clamping screw 17 extends with play through slot 16 of the corresponding cutting tip holder, which has a bearing surface 20 for head 19 of clamping screw 17. Axis 21 of clamping screw 17 is in a plane which with the two slot surfaces 61,62 or 71,72 or 81,82 form an essentially equally large angle. In the embodiment shown in the figures axis 21 moreover has a directional component extending in a radial plane of cutting tool 1.By tightening of centrally placed clamping screw 17 perpendicular forces are produced both on the first slot surface turned away from the cutting tip and on the second slot surface adjacent to the cutting tip. The surface support results in this case by slot surface 61,71 or 81, which is essentially perpendicular to the cutting force acting on the main cutting edge.

Play S (see Figure 1) between the inside hole 16 in the cartridge and the shank of clamping screw 17 is large enough to adjust the individual cutting tips exactly in relation to one another, since threaded hole 18 in the tool body is already bored so precisely that a rough position preadjustment is produced.

By twisting of support screws 12 and 13, with clamping screw 17 loosened, cutting tip holder 53, 54 or 55 is so swivelled by using play S and by the further bearing on its plane surface that the main cutting edge of corresponding cutting tips 51 to 53 or 41 to 43 always remains in preset radial plane 91 to 93.

To adjust the cutting tip holder in a direction parallel to the axis of cutting tool 1 there corresponds to each cutting tip holder an additional adjustment pin 23, which engages in an angled adjustment slot 24 of the respective cutting tip holder. Adjustment pin 23 is engaged with a corresponding threaded hole 25 in tool body 11, and slot 24 is so matched to a head 26 of adjustment pin 23 that by screwing adjustment pin 23 into threaded hole 25, with clamping screw 17 loosened, a shift of the cutting tip holder (for example 55) occurs in feed direction V.

It can be seen from Figures 1 and 2 that the cutting tip holders can be adjusted in the radial direction.

Since - as can be seen in Figure 1 - several cutting tip holders are placed in an axial plane of cutting tool 1, this design of the support of the individual cutting tip holders requires for the case when all cutting tips in mounted condition on the tool body are to be adjusted with free access, that in each case the cutting tip holders in an axial plane, e.g., cutting tip holders 45 and 55 according to Figure 2, have an axial offset VA and a radial offset VA.

Figures 3 to 12 show embodiments of the cutting tool according to the invention, with which the axial and radial offsets VA and VR can be minimized or eliminated. For simplification of the description, those components of the cutting tool in the embodiment according to Figures 3 to 12, which correspond to those of Figures 1 and 2, are provided with the same reference numbers.

The embodiments according to Figures 3 to 12 differ from the embodiment of the cutting tool according to Figures 1 and 2 essentially by the fact that the cutting tip holders are supported in a different way in an otherwise comparably designed slot in tool body 11. In the embodiment according to Figure 3 are seen three cutting tip holders 110, 120 and 130, which are also designed like a right parallelepiped and are inserted into slots 111,121 and 131 matching the right parallelepiped. Each cutting tip holder, like the cutting tip holders described in relation to Figures 1 and 2, has a countersunk hole 37 (compare Figures 2 and 3), which serves as support surface for the head of clamping screw 17, which thus can be inserted countersunk in the cutting tip holder. In Figures 3 to 12 countersunk hole 37 is shown only diagrammatically.Also not shown is the inside bore coming out in this countersunk hole surface 37 through which the shank of clamping screw 17 runs parallel with play S.

The clamping screw presses the respective cutting tip holder 1 10. 120 or 130 flat against the first slot surfaces covered by the cutting tip holder in Figures 3, 4, 9 and 10, surfaces that were identified by reference numbers 61,71 and 81 in tha case of the cutting tool according to Figure 1 and 2. By reference numbers 112,122 and 132 are identified the second slot surfaces running at right angles to the first slot surfaces; the cutting tip holders are supported against the second slot surfaces by specially configurated support elements 200.

As shown in detail in Figure 5, support elements 200 are formed by support eccentric pins, which extend in a direction that is perpendicular to the first slot surface, against which the cutting tip holder is pressed flat. By twisting of support eccentric pins 200, eccentric section 201 travels so that the distance of the cutting tip holder from the second slot surface changes, as a result of which the cutting tip holder can be put in a tilted position.

The principle of the eccentric adjustment is best shown in Figure 5. Support eccentric adjustment is best shown in Figure 5. Support eccentric pin 200 exhibits, besides a cylindrical section 202, an eccentric section 201, which preferably extends over an angular area a, which is about half as large as the angular area in Figure 5 identified by (3,which marks off the sector by which the support eccentric pin projects from cutting tip holder 130. In its front surface 203, eccentric pin 200 has an inside hexagonal slot 204, so that it can be twisted by its suitable tool. Eccentric pin 200 is guided by a cylindrical section 202 positioned in a partially cylindrical slot 205 in cutting tip holder 130.On the side turned away from front surface 203, support eccentric pin 200 can be provided with a threaded section (not shown in detail in the Figure), which cooperates with a correspondingly shaped slot in the tool body which is also not shown.

By applying a tool on inside hexagonal slot 204 and by twisting eccentric pin 200 by angle (P--CI)I2, the maximum distance DmaX can be reduced to distance Admin. By suitable adjustment of dimension R to diameter D of support eccentric pin 200, the ratio of DmaX to Dmin can be suitably predetermined.

Support eccentric pin 200 can be so designed that it can transfer, in point or linear form, to tool body 11 the support force applied by clamping screw 17.

Figure 6 shows an embodiment in which the support eccentric pin transfers the force linearly. For this purpose, the support eccentric pin is formed of an essentially cylindrical pin, which exhibits a cam section 206 over its entire length in the area in which it projects from slot 205 acting as a guide. The cross section of the eccentric pin is thus made the same over its entire length.

If the eccentric pin is supported linearly on slot surface 132, care must be taken that axis 207 is exactly perpendicular to the first slot surface, against which the cutting tip holder is pressed flat. This generally represents no difficulty since the slot is formed exclusively of surfaces that in each case run at right angles to one another.

Of course, it is also possible to design the support eccentric pin so that the support force is transferred in point form as in Figure 7. In this case the guiding of the eccentric pin can still be designed as shown in Figures 5 and 6. Further, the eccentric pin is in turn designed essentially cylindrical but, departing from the configuration according to Figure 6, it has at certain points at least one knob-shaped elevation 208, so that by twisting of eccentric pin 200' a tilt adjustment of the cutting tip holder can be carried out.

Figure 8 shows another embodiment of an eccentric pin 200", which differs from that according to Figure 7 in that knob-shaped elevations 208 are replaced by eccentric partial sections 209, which in cross section are also designed like those in the embodiment according to Figure 6.

To secure the eccentric pin better in the various turning positions, it can be advantageous to allow the eccentric pin, on the side turned away from the front surface, to engage a threaded section in a correspondingly shaped slot in the tool body.

Figure 9 shows another embodiment of the eccentric pin, which is identified by the reference number 400. This eccentric pin, which in Figure 9 is shown on an enlarged scale, is preferably used together with a cutting tip holder according to Figure 10, which as a result of the arrangement of the cutting tip corresponds to cutting tip holder 120 according to Figure 3 and therefore is identified by the same reference number. Instead of countersunk hole 37 according to Figure 3, cutting tip holder 120 according to Figure 10 has a cylindrical countersunk slot 124 for inserting the head of clamping screw 17. The outside surface of the cutting tip holder opposite slot surface 122 according to Figure 3 is identified by 124A and the surface of the cutting tip holder opposite the other slot surface 123 is identified by 125.Matching slots 127 are formed in these surfaces 124A and 125, whereby matching slots 127 of surface 124A are offset to axis 21 of clamping screw 17, i.e., placed on different sides of a line perpendicular to surface 124A and passing through this axis. The axial ends of matching slots 127 are defined by semicylindrical surfaces 128, whereby the diameter of the halfcylinder defining these surface corresponds to diameter D405 or D406 of end sections 405 and 406 of eccentric pin 400 according to Figure 9. Length L of eccentric pin 400 is slightly smaller than height H of cutting tip holder 120.So that eccentric pin 400, which between its two end sections 405 and 406 carries an eccentric section 401 greater in diameter, can be introduced into matching slots 127 from a direction perpendicular to outside surfaces 124A or 125, there is provided in these outside surfaces an additional free space 126, whose height H 126 matches the length of eccentric section 401. Diameter D401 of eccentric section 401 is somewhat larger than diameter D405 or D406 of the end sections, which are offset therefrom by double the eccentricity dimension E401. This eccentricity dimension is preferably in the range between 3% and 5% of diameter D401.

For storage and assembly reasons it is advantageous to handle the cutting tip holders together with the individual eccentric pins 400 as a complete unit, at which time care is taken that the eccentric pins cannot slip out of the matching slots. For this purpose, transition sections 129 - adjacent to the respective outside surfaces 124A or 125of matching slots 127 can be compressed toward one another, as indicated by arrow P in Figure 10. By compressing of these sections 129 in the case of already inserted eccentric pins 400, an undercut matching slot in thus formed in which eccentric pin 400 is able to turn freely.

Eccentric pin 400 preferably is made of tempered steel with the usual surface roughness, while cutting tip holder 120 is formed of a casting, in which matching slots 127 are cast as one piece. It has been found that if semicylindrical surfaces 128 are formed from a cast or quality-cast surface and end sections 405 and 406 of eccentric pin 400 are formed with an average roughness, a favorable friction and sliding surface mating can be achieved.

It can be seen from Figure 3 that the adjustment of the individual cutting tip holders now takes place from a direction which is parallel to second slot surface 112,122 or 132 and in the embodiment according to Figure 3 - perpendicular to the first slot surface, against which the cutting tip holders are pressed flat. This design makes it possible to place cutting tip holders 120 and 130 radially directly adjacent in the tool body, and moreover the axial offset of these cutting tip holders can be kept very small, since clamping screws 17 inserted in countersunk holes 37 are always accessible by their slanted position, i.e., the slanting of axis 21 as seen in Figure 10.

To be able to adjust the cutting tip holders also in axial direction or parallel to second slot surface 112, additional adjustment pins 300 are provided, which can be designed in a way similar to support eccentric pins 200 or 200', 200" or 400. But the adjustment pins can also be designed, as shown in Figure 2, with the feature that axes 27 of adjustment pins 23 shown there run skewed 90% so that they run parallel to axes 207 or 407 of support eccentric pins 200 or 400.

With this embodiment, adjustment pin 23 engages in an adjustment slot 24 in the corresponding cutting tip holder and is engaged with a corresponding thread hole 25 in tool body 11, whereby slot 24 is matched to head 26 of the adjustment pin, so that by screwing pin 23 in threaded hole 25, with clamping screw 17 loosened, a shift of the cutting tip holder in feed direction V takes place. For this purpose, adjustment slot 24 is made ramp-shaped on the side turned toward the corresponding cutting tip and, with axis 27 of adjustment pin 23, forms a predetermined ramp angle y. Axis 27 of adjustment pin 23 is then placed in a plane, which is also perpendicularto the first slot surface of tool body 11, against which the cutting tip holder is pressed flat.So as not to overload the adjustment pin, head 26 is supported on the side turned away from slot 24 in a support slot of tool body 11 matched with head 26. The adjustment pin head in this case can be designed cylindrical and can be guided in a support slot matched with this cylindrical configuration. Ramp-shaped adjustment slot 24 is provided with a slot bottom, which viewed in a section perpendicular to axis 27 of adjustment pin 23 has also or at least approximately the shape of a half-cylinder, which is identical with the cylinder of adjustment pin head 26. With this design the particular advantage is attained that the cutting tip holder during adjustment of the angular position with the help of support eccentric pins 200 is shifted in a plane essentially parallel to the first slot surface, against which the cutting tip holder is clamped flat, and thus is not tilted.

In the embodiment according to Figure 3 adjust ment eccentric pin 300 is supported against a slot surface 113,123 or 133 of tool body 11. In the embodiment according to Figure 4, this applied only to the cutting tip holder cutting tip holder 140 in Figure 4 is supported by adjustment eccentric pin 300 on an outside surface 151 of cutting tip holder 150, a surface that is adjacent to cutting tip holder 140.

Figures 11 and 12 show other variants of mounting the various cutting tip holders on tool body 11. Of particular importance in this connection is the arrangement of cutting tip holders 160 and 170 according to Figure 10. It can be seen that in this embodiment of the cutting tool neither an axial offset VA nor a radial distance VR is necessary and yet an adequate adjustment of the cutting tip holders in relation to one another is made possible. Also tightening of the clamping screw (not shown) is possible, since the heads of clamping screws 17 are inserted countersunk in countersunk hole 37, whose surfaces so run relative to each other that sufficient free space remains to introduce the two corresponding clamping screws 17 from the outside and to tighten them by a suitable tool.

In the adjustment of the cutting tool described above, the procedure is as follows: First the prismatic cutting tip holder is clamped loosely in the corresponding slot merely by clamping screw 17, so that the head of screw 17 presses with comparatively slight force on head support surface 20. In case support and adjustment eccentric pins 200 according to Figure 6 are provided with a threaded section turned away from the front surface, a section that works together with a threaded hole in tool body 11, the eccentric pins are first screwed into the slots and the cutting tip holder is then introduced into the corresponding slot in such a way that the cylindrical sections of the eccentric pins slip into bore slots 205.

Then clamping screw 17 is introduced. By twisting of support eccentric pins 200, 200', 200" or 400, the cutting tip holder is tilted with optical control of the cutting edge until the main cutting edge of the cutting tip has a desired position arrangement in regard to the workpiece, and the eccentric section comes to extend by the desired diameter. During these adjustment movements, the cutting tip holder remains with its plane surface in flat bearing contact with the corresponding slot surface of tool body 11.

After the clearance angle and the working diameter of the cutting tip are adjusted, a positioning of the cutting tip holder in feed direction V takes place, for which either clamping pin 23 or adjustment eccentric pin 300 is twisted. In this connection, nothing is changed on the adjustment of the cutting tip adjusted by the support eccentric pins 200 or 400, since the cutting tip holder on the eccentric sections or knobs can slide along the second slot surface with which they cooperate. Then, central clamping screw 17 is tightened solidly and the cutting tip holder is adjusted exactly.

Especially with the configuration of eccentric pin 400 according to Figure 9 and of cutting tip holder 120 according to Figure 10, extremelygreatsupport forces can be transferred, so that adjustments of the cutting tip holder in the pJm range itself can then be made, if the cutting tip holder is already roughly fixed in position under pretension in the slot by clamping screw 17.

The invention thus provides a cutting tool with a replaceable cutting tip, which is fastened on a prismatic cutting tip holder, which, for its part, can be adjustably fastened on the tool body. The tool body exhibits, for inserting the cutting tip holder, a slot formed from two surfaces running at an angle to one another, and the cutting tip holder is penetrated, with play, by a clamping screw, which extends in a clamping direction forming an essentially equally large angle with the two slot surfaces and by which the cutting tip holder can be pressed flat against the one slot surface and, by two adjustable support elements, against the other slot surface. With the described cutting tool, the adjustment of the cutting tip holder or several cutting tip holders in relation to one another can be performed exactly and reliably and at the same time with a minimum of adjustment manipulations.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Claims (17)

1. In a cutting tool having a tool body including at least one slot defined by first and second nonparallel slot surfaces a cutting tip holder fastened in said slot by a head of a clamping screw having shaft extending through said tip holder with lateral play, said clamping screw shaft extending in a direction forming an equally large angle with respect to said first and second slot surfaces whereby said clamping screw can press said cutting tip holder towards said first and second slot surfaces, wherein said cutting tip holder comprises: a prismatic body having a shape corresponding to that of said slot; and adjustable support elements positioned between said prismatic body and said second slot surface, said support elements comprising support eccentric pins rotatable about an axis essentially parallel to said second slot surface.

2. Cutting tool as in Claim 1, wherein said cutting tool is a drilling or milling tool, wherein said cutting tip holder and slot have the shape of a right parallelepiped, wherein at least one of said support eccentric pins has an eccentric section which extends over a predetermined angular width, and wherein said eccentric section is turned toward second slot surface of said cutting tip holder.

3. The cutting tool of Claim 2, wherein said at least one support eccentric pin comprises a cylindrical pin having a cam section, said pin fitting in a guide slot of said prismatic body with said cam section projecting therefrom.

4. Cutting tool as in Claim 3, wherein said at least one support eccentric pin has a threaded section with which said pin can be screwed into a threaded hole of the tool body.

5. Cutting tool as in Claim 3, wherein an axis of said guide slot runs parallel to said second slot surface, and is spaced therefrom by between 0.1 and 0.3 times the diameter of said guide slot.

6. Cutting tool as in Claim 1, wherein said cutting tool is a drilling or milling tool, wherein said cutting tip holder and slot have the shape of a right parallelepiped, and wherein at least one of said support eccentric pins has an eccentric section which extends over a middle region of a surface of said cutting tip holder turned toward said second slot surface.

7. Cutting tool as in Claim 6, wherein said support eccentric pin comprises a stepped cylindrical pin having concentric end sections supported in matching slots of said cutting tip holder, and a cylindrical eccentric section positioned between said end sections and having a greater diameter than said end sections, said eccentric section fitting in a free space formed in said cutting tip holder.

8. Cutting tool as in Claim 7, wherein said matching slots are defined by semicylindrical surfaces whose outer edges are compressible toward one another.

9. Cutting tool as in Claim 7, wherein the eccentricity dimension of said eccentric section is in the range of 3% to 5% of the diameter of said eccentric section.

10. Cutting tool as in Claim 8, wherein said semicylindrical surfaces and the surfaces of said concentric end sections of said eccentric pin exhibit surface roughness matching one another.

11. Cutting tool as in Claim 1, wherein said support eccentric pin has an inside hexagonal slot on an end surface thereof for turning adjustment.

12. Cutting tool as in Claim 1, wherein said support eccentric pins are mutually offset on the opposite sides of a line perpendicular to a surface of said prismatic body facing said second slot surface, said line passing through an axis of said clamping screw.

13. Cutting tool as in Claim 2 including an additional adjustment device in the form of an adjustment pin for supporting said cutting tip holder against a supporting surface which is perpendicular to said second slot surface, wherein said adjustment pin is formed by a second adjustment eccentric pin having an axis which runs parallel to that of said support eccentric pins.

14. Cutting tool as in Claim 13, wherein said supporting surface is formed by a slot surface of said tool body.

15. Cutting tool as in Claim 13, wherein said support surface is formed by a surface of an adjacent cutting tip holder.

16. A cutting tool comprising: a tool body having a valley with first and second surfaces; a cutting tip holder having a first surface to engage the first surface of the valley and a plurality of cams arranged to project into engagement with the second surface of the valley; and means to clamp the tip holder into the valley of the tool body.

17. A cutting tool substantially as described in the description with reference to Figures 3 to 12 of the drawings.