Rotary cutting tools

Abstract

The invention discloses a rotary cutting tool (10), in particular a drill, comprising a shank (12) and a replaceable cutting tip (14). For this purpose, a locking geometry (16) having a first type of undercut (28) and a torque transmission geometry (24) is provided on the shank (12). A locking projection (32) having a torque transmission relative geometry (34) is provided on the cutting tip (14), wherein, in the mounted state, the locking projection (32) engages in the first type of undercut (28) and the torque transmission relative geometry (34) abuts the torque transmission geometry (24). The rotary cutting tool (10) further comprises a fixing unit (38) for holding the cutting tip (14) on the shank (12).

Description

Technical Field

[0001] The present invention relates to a rotary cutting tool, in particular a drill having a shank rotatable about a rotational axis and a replaceable cutting tip connectable to the shank, wherein a locking geometry is arranged on the shank, the locking geometry having a first type of undercut and a torque transmission geometry, wherein the first type of undercut acts in the axial pull-out direction and the torque transmission geometry is oriented in the rotational direction, wherein a locking projection having a torque transmission counter-geometry is arranged on the cutting tip, and wherein, in the mounted state, the locking projection engages in the first type of undercut and the torque transmission counter-geometry abuts the torque transmission geometry. Background Art

[0002] Rotary cutting tools of this type are known in the prior art. Generally, the goal is to ensure that the cutting tip can be quickly and easily mounted on the shank. At the same time, the cutting tip should remain securely mounted on the shank in its mounted state. These two requirements are clearly conflicting, so in known rotary cutting tools, a compromise between easy mounting and secure retention is always necessary. Summary of the Invention

[0003] The object of the present invention is therefore to provide a rotary cutting tool in which the cutting tip can be quickly and easily mounted on the shaft and remains securely on the shaft in the mounted state. In particular, it should be possible to replace the cutting tip "from the front." Therefore, the end of the rotary cutting tool on the clamping side should not be accessible for replacing the cutting tip.

[0004] The above-mentioned object is achieved by a rotary cutting tool of the type mentioned above, which is equipped with a fixing unit that holds the cutting tip on the shank in the installed state. In this type of rotary cutting tool, in a first step, the cutting tip is installed on the shank by assuming a first rotational position relative to the shank and axially inserting it into a receiving recess on the shank. In a second step, the cutting tip is rotated relative to the shank so that the locking protrusion engages with the first type of undercut. At the same time, the torque transmission relative geometry is placed against the torque transmission geometry. Therefore, during operation of the rotary cutting tool, torque can be transmitted from the shank to the cutting tip in a planar manner. At the same time, the cutting tip is fixed to the shank in the axial direction by the first type of undercut. The fixing unit reinforces the axial retention of the cutting tip on the shank. The fixing unit also prevents the cutting tip from rotating relative to the shank so that the locking protrusion disengages from the locking geometry. Therefore, the cutting tip is particularly firmly and reliably held on the shank. And its installation is very simple.

[0005] The effect of the fixing unit can be a friction lock and / or a form lock.

[0006] Preferably, the torque transmission geometry comprises a flat torque transmission surface and / or a curved torque transmission surface.The torque transmission geometry may also consist of a plurality of flat or curved surface segments.

[0007] The same applies to the torque transmission counter geometry. It is therefore also preferred that this comprises a flat torque transmission counter surface and / or a curved torque transmission counter surface. The torque transmission counter geometry can also consist of a plurality of flat or curved surface segments.

[0008] The locking projection can be moved back relative to the axial workpiece side front face of the cutting tip. In other words, when viewing the cutting tip in the radial direction, the locking projection can be moved back relative to the front face in a stepped manner.

[0009] Preferably, at least two locking projections are arranged on the outer circumference of the cutting tip, in particular, diametrically opposite each other. Therefore, preferably, two locking geometries are also provided on the shank. Alternatively, three or four locking projections may be provided, along with a corresponding number of locking geometries on the shank.

[0010] The locking geometry can include a second type of undercut that prevents the torque transmission relative geometry from lifting away from the torque transmission geometry, wherein, in the installed state, the locking projection engages in the second type of undercut. The second type of undercut thus prevents the cutting tip from rotating relative to the shank in the removal direction in a form-locking manner. This ensures that the cutting tip is securely held on the shank in the installed state. The second type of undercut is designed so that the locking projection can easily engage with it during installation.

[0011] According to one embodiment, the locking geometry comprises a base body and a retaining finger, wherein the base body extends substantially axially relative to the axis of rotation, and wherein the retaining finger extends substantially circumferentially from the cutting tip side of the base body and projects circumferentially relative to the base body. This basic configuration of the locking geometry is well-proven in the prior art and is robust.

[0012] Preferably, the second type of undercut is formed by the retaining finger. Thus, the protruding section of the retaining finger extends both circumferentially and axially. Its axial component is oriented toward the clamping-side shank end. This makes the second type of undercut easy to implement. The dimensions of the second type of undercut can be selected based on the dimensions of the axial component of the protruding section of the retaining finger. This determines the required installation force for the locking projection to engage the second type of undercut and, conversely, the retention force generated by the second type of undercut.

[0013] It is also preferred that the first type of undercut is formed by the retaining finger. As already mentioned, the retaining finger extends substantially in the circumferential direction. Therefore, the first type of undercut is arranged on the axial side of the retaining finger, that end of the shank facing the clamping side. Therefore, the first type of undercut can be easily implemented.

[0014] In one variant, the fixing unit includes a biasing member, by means of which the retaining finger can be pressed axially against the locking projection in the installed state. This secures the cutting tip to the shaft in a force-locked or friction-locked manner; in particular, it prevents the cutting tip from rotating relative to the shaft. If the locking projection is seated in an undercut of the second type, the biasing member further reinforces the form-locking retention produced by the undercut of the second type. This is because the biasing member prevents the locking projection from overcoming the retaining effect of the undercut of the second type, for example, by elastic deformation.

[0015] The loading means may comprise a clamping screw, by means of which the retaining finger can be loaded with pressure in the direction of the base body, so that the locking projection is clamped axially between the retaining finger and the axial stop surface on the shank. The clamping screw thus at least brings the retaining finger and the locking projection into abutment with one another under preload. The retaining finger can also be elastically deformed in the direction of the locking projection. This ensures that the cutting tip is held particularly securely on the shank.

[0016] Alternatively, the loading member is a clamping disc positioned between the cutting tip and the shank so that, when the cutting tip is installed, the retaining finger is pressed axially against the locking projection. Specifically, the clamping disc is located axially between the cutting tip and the base of the receiving recess provided for the cutting tip in the shank. Strictly speaking, the locking projection is therefore located axially between the clamping disc and the section of the locking geometry that forms the first type of undercut, specifically the retaining finger. The clamping disc can achieve two effects, either individually or in combination. On the one hand, the clamping disc can be used to compensate for any tolerances in the shank and / or the cutting tip, allowing the cutting tip to enter an abutment defined in the shank, specifically in the locking geometry, specifically in the axial direction. On the other hand, the clamping disc can introduce a degree of elasticity into the composite structure consisting of the locking projection and the locking geometry. Specifically, the clamping disc is preferably elastically deformable in the axial direction. As a result, the locking projection is pressed against the retaining finger, starting from the clamping end of the shank. This also ensures that the cutting tip is particularly securely retained on the shank.

[0017] The clamping disc can be positioned on the side of the cutting tip facing away from the retaining fingers and includes at least one supporting geometry for positioning the cutting tip on the shank. Thus, the clamping disc is positioned on the side of the shank end that faces the cutting tip on the clamping side. Because the clamping disc can be produced within narrow tolerances, the supporting geometry can be used to precisely position the cutting tip on the shank. Specifically, the shank, and in particular the locking geometry provided thereon, as well as the cutting tip, can be produced within relatively rough tolerances. These tolerances can then be compensated for by the clamping disc.

[0018] Preferably, the first support geometry facing the handle and the second support geometry facing the cutting tip are different. In particular, the support geometries do not overlap. This makes it possible to achieve an improvement in the torque transmission from the cutting tip to the handle, and vice versa. For example, the first support geometry comprises a curved support surface, which reduces the bending stresses generated by the torque during operation of the rotary cutting tool in the locking geometry area. The second support geometry may comprise a flat support surface, which cooperates with the cutting tip. A corresponding flat surface on the cutting tip can be produced relatively easily and accurately. In addition, even if torque peaks occur during operation of the rotary cutting tool, the cutting tip can be reproducibly supported on the second support geometry over its entire surface.

[0019] The clamping disc is advantageously a separate component from the shank and cutting tip, specifically, wherein the clamping disc is replaceable. Thus, the clamping disc can be produced separately from the shank and cutting tip. This makes it possible to produce the clamping disc with different tolerances than when producing the shank and / or cutting tip. Consequently, a different material can be selected for the clamping disc than for the shank and / or cutting tip. This facilitates the already discussed effects of tolerance compensation and elasticity.

[0020] In an alternative embodiment, the fixing unit comprises a fixing pin. An opening associated with the fixing pin is also present on the cutting tip, wherein the fixing pin extends axially from the shank and engages in the opening when the cutting tip is mounted. Thus, the cutting tip is further fixed to the shank.

[0021] The retaining pin may include a pin shank and a pin head, and the opening may include a third type of undercut. The third type of undercut acts axially, and in a first rotational position of the cutting tip relative to the retaining pin, the pin head is positioned within the opening and engages in the third type of undercut, thereby securing the cutting tip to the shank in the axial withdrawal direction. The third type of undercut cooperates with the retaining pin to axially secure the cutting tip to the shank. Preferably, the first rotational position coincides with a relative position of the cutting tip and the shank, wherein the torque transmission geometry abuts the torque transmission relative geometry. This ensures that the cutting tip is securely secured to the shank.

[0022] In the first rotational position, the outer surface of the pin head and / or the outer surface of the pin shank can further abut the associated outer surface of the opening, in particular, be frictionally locked with said associated outer surface. Thus, the cutting tip is also secured against undesirable rotation.

[0023] Preferably, the pin head has an elliptical cross-section, and the opening of the cutting tip includes a feed section designed with a corresponding elliptical cross-section. The pin head can thus be axially inserted into the opening in a second rotational position, which differs from the first rotational position. The pin head can thus be easily pushed axially through the feed section. The feed section is followed by an end section in the direction of the cutting tip point, forming a third type of undercut. To this end, the diameter of the end section exceeds the diameter of the feed section, at least in part. By rotating the cutting tip relative to the pin head from the second rotational position to the first rotational position, the cutting tip can engage with the end section, i.e., with the third type of undercut. This ensures that the cutting tip is securely fixed to the shank.

[0024] The retaining pin can consist of two retaining pin halves separated by an axial gap. The retaining pin halves are elastically deformable in the radial direction. Thus, the retaining pin is retained within the opening by the radially acting spring force generated by the elastic formability. This frictionally locks the cutting tip to the shank, resisting rotation.

[0025] In an embodiment in which the fixing unit comprises a fixing pin, the cutting tip is mounted on the shank as follows. First, the cutting tip is brought into a second rotational position relative to the shank. Then, the fixing pin, in particular the pin head, is pushed axially into the feed section of the opening until the cutting tip abuts the axial base of a receiving recess provided for it on the shank. The pin head is then located in the end section of the opening, but has not yet engaged in the undercut of the third type. The cutting tip is then moved relative to the shank into a first rotational position. This causes the pin head to engage in a portion of the end section of the opening, the diameter of which exceeds the diameter of the feed section. In other words, the pin head engages with the axially acting undercut of the third type. In order to remove the cutting tip from the shank, the above steps are performed in the reverse order and direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is explained below with the aid of the design examples shown in the accompanying drawings. The figures show:

[0027] - Figure 1 According to a first embodiment of the present invention, a rotary cutting tool in the form of a drill,

[0028] - Figure 2 In the form of a separate diagram Figure 1 The handle of the rotary cutting tool,

[0029] - Figure 3 In the form of a separate diagram Figure 1 The cutting tip of the rotary cutting tool,

[0030] - Figure 4 According to a second embodiment of the present invention, a rotary cutting tool in the form of a drill,

[0031] - Figure 5 During the installation process Figure 4 Rotary cutting tool,

[0032] - Figure 6 In the form of a separate diagram Figure 4 and 5 a shank of a rotary cutting tool and a clamping disc mounted on the shank,

[0033] - Figure 7 In the form of a separate diagram Figures 4 to 6 The holding disc for the rotating cutting tool,

[0034] - Figure 8 A rotary cutting tool in the form of a drill according to a third embodiment of the invention, during an installation procedure, in a perspective front view, and

[0035] - Figure 9 Figure 8 Rotary cutting tool, shown in perspective rear view. DETAILED DESCRIPTION

[0036] Figures 1 to 3 A rotary cutting tool 10 according to a first embodiment is shown. The rotary cutting tool 10 is designed as a drill, which is rotatable about an axis of rotation 8 .

[0037] It includes Figure 1 1 and 2. The shank 12 is shown only partially, and a cutting tip 14 is replaceably coupled thereto.

[0038] For this purpose, a locking geometry 16 is provided on the handle 12 .

[0039] The locking geometry comprises a base body 18 which extends substantially axially, ie along the axis of rotation 8 .

[0040] Furthermore, a holding finger 20 extends from the cutting tip-side end of the basic body 18. The holding finger extends substantially in the circumferential direction relative to the rotation axis 8 and projects relative to the basic body 18. The holding finger 20 thus comprises a projecting section 22.

[0041] Furthermore, the locking geometry 16 comprises a torque transmission geometry 24 , which is oriented in the direction 26 of rotation of the rotating cutting tool 10 about the axis of rotation 8 .

[0042] In the illustrated embodiment, the torque transmitting geometry 24 consists of a flat torque transmitting surface 24a and a curved torque transmitting surface 24b (see FIG. Figure 2 ).

[0043] The holding finger 20 , or more precisely the protruding section 22 of the holding finger 20 , also forms an undercut 28 of a first type, which acts opposite the axial pull-out direction, ie along the axis of rotation 8 .

[0044] The protruding section 22 of the holding finger also forms a second type of undercut 30 , which hinders a rotation of the cutting tip 14 relative to the shank 12 in the rotational direction 26 .

[0045] The cutting tip 14 has a locking projection 32 which comprises a torque-transmitting relative geometry 34 , which is oriented in the direction of rotation 26 .

[0046] Corresponding to the torque transmission geometry 24, the torque transmission relative geometry 34 consists of a flat torque transmission relative surface 34a having a surface normal oriented substantially in the circumferential direction and a curved torque transmission relative surface 34b. Figure 3 ).

[0047] The locking projection 32 is set back relative to the axial front face 36 of the cutting tip along the axis of rotation 8 and thus forms a step.

[0048] In the mounted state of the rotary cutting tool 10 , the locking projection 32 of the cutting tip 14 engages both in the first type of undercut 28 and in the second type of undercut 30 .

[0049] Furthermore, the torque transmission counter geometry 34 abuts the torque transmission geometry 24 .

[0050] The cutting tip is secured against an undesired relative rotation in the rotational direction 26 relative to the shank 12 by the second type of undercut 30. Consequently, the second type of undercut 30 also hinders the torque transmission opposing geometry 34 from lifting off the torque transmission geometry 24.

[0051] The axially effective undercut 28 of the first type prevents axial withdrawal of the cutting tip 14 from the shank 12 .

[0052] A fixing unit 38 is also provided, which holds the cutting tip 14 on the shank 12 in the mounted state.

[0053] In the embodiment shown, this fixing unit 38 comprises a loading member 40 , by means of which the retaining finger 20 is pressed axially against the locking projection 32 in the mounted state.

[0054] All that matters is the relative relationship of the retaining finger 20 to the locking projection 32 , so that the locking projection 32 is also pressed against the retaining finger 20 by the loading member 40 .

[0055] In the first embodiment, the loading member 40 is a clamping screw 42 .

[0056] The holding finger 20 can be loaded with pressure in the direction of the basic body 18 by means of a clamping screw 42 , so that the locking projection 32 is clamped axially between the holding finger 20 and an axial stop surface 44 on the shank 12 .

[0057] The stop surface 44 represents the bottom surface of the locking geometry 16 .

[0058] Furthermore, the rotary cutting tool 10 has a coolant channel. The shank 12 comprises a central supply channel 46 extending substantially along the axis of rotation 8 .

[0059] Furthermore, the cutting tip 14 has a connecting pin 48 for the coolant supply, which also extends substantially along the axis of rotation 8. Two outlet lines 50, 52 diverge from here in a forked manner and are Figure 1 and 3 The coolant may be conducted into the processing zone via outlet lines 50, 52.

[0060] The mounting of the cutting tip 14 on the shank 12 is performed as follows.

[0061] First, the cutting tip 14 is brought into a rotational position relative to the shank 12, in which it can be pushed past the protruding section 22 of the retaining finger 20 into the locking geometry 16. The cutting tip is thus moved along the rotational axis 8 until it abuts the stop surface 44. Consequently, the connecting pin 48 is also pushed into the end section of the supply channel 46 and thereby coupled thereto in a coolant-conducting manner.

[0062] The cutting tip 14 is then rotated relative to the shank 12 in the direction of rotation 26 until the torque transmission geometry 24 and the torque transmission counter-geometry 34 abut one another.

[0063] This also causes the locking projections 32 to engage with the first type of undercuts 28 and the second type of undercuts 30 .

[0064] The clamping screw 42 is then tightened, so that the holding finger 20 is elastically deformed in the direction of the base body 18 . The holding finger 20 thus clamps the locking projection 32 against the stop surface 44 .

[0065] The cutting tip 14 is thus securely held on the shank 12. The outlet lines 50, 52 can now also be supplied with coolant via the supply channel 46 in the shank 12.

[0066] In order to remove the cutting tip 14 from the shank 12 again, it is merely necessary to carry out the described installation steps in reverse order and with the opposite direction of movement.

[0067] Figures 4 to 7 A second embodiment of a rotary cutting tool 10 is shown.

[0068] Only the differences from the first embodiment will be discussed. Therefore, identical or corresponding parts have the same reference numerals.

[0069] As in the first embodiment, the rotary cutting tool 10 according to the second embodiment also has a fixing unit 38 including a loading member 40 .

[0070] However, the loading member 40 is now a clamping disc 54 .

[0071] This is a separate component from the shank 12 and cutting tip 14 .

[0072] In the mounted state of the rotary cutting tool 10 , the clamping disc 54 is arranged between the cutting tip 14 and the shank 12 . It is positioned on the side of the cutting tip 14 facing away from the holding finger 20 .

[0073] In other words, the clamping disk 54 abuts the stop surface 44 of the shank 12 on the one hand and the end surface 56 of the cutting tip 14 on the clamping side on the other hand.

[0074] The clamping disk 54 comprises a first support geometry 58 that, in the mounted state, engages the torque transmission geometry 24. The clamping disk 54 is thus positioned on the shank 12 in the rotational direction 26 by means of the first support geometry 58. In the illustrated embodiment, both the torque transmission geometry 24 and the first support geometry 58 are composed of curved surface sections and flat surface sections.

[0075] The clamping disc 54 further comprises a second support geometry 60 that, in the mounted state, engages the torque transmission counter geometry 34 of the cutting tip 14. Thus, the second support geometry 60 helps position the cutting tip 14 relative to the clamping disc 54 and, therefore, the cutting tip 14 relative to the shank 12 as a whole.

[0076] In the illustrated embodiment, the second support geometry 60 comprises a substantially planar support surface. The torque transmitting opposing geometry 34 also comprises a substantially planar torque transmitting opposing surface.

[0077] Between the supporting geometries 58, 60 there is a supporting area which supports the torque introduced by the shank 12 into the cutting tip 14. The same is true for torques directed in the opposite direction.

[0078] The clamping disc 54 presses the holding finger 20 axially against the locking projection 32. Again, it is only important that the interaction between the holding finger 20 and the locking projection 32 occurs such that the locking projection 32 is also pressed axially against the holding finger 20.

[0079] In particular, the axial thickness of the clamping disc 54 is dimensioned so that this pressing occurs.

[0080] Furthermore, the clamping disc 54 has a certain degree of elasticity. Compressing the clamping disc between the cutting tip 14 and the shank 12 generates a force by which the holding finger 20 and the locking projection 32 are pressed against each other as an elastic reaction force.

[0081] The mounting of the cutting tip 14 on the shank 12 is essentially the same as in the first embodiment. The only difference is that, in a previous step, i.e. before the cutting tip 14 is mounted on the shank 12, the clamping disc 54 is placed against the stop surface 44 and oriented in the direction of rotation 26 by placing the first support geometry 58 against the torque transmission geometry 24.

[0082] Of course, when the rotary cutting tool 10 is mounted according to the second embodiment, the clamping screw 42 is not yet tightened.

[0083] In the rotary cutting tool 10 according to the second embodiment, it is also possible to use the same combination of shank 12 and cutting tip 14 with different clamping discs 54 .

[0084] Different clamping discs 54 can be used to compensate for wear occurring during the service life of the rotary cutting tool 10. Alternatively or additionally, the compression force existing between the holding finger 20 and the locking projection 32 can be influenced in a targeted manner by using different clamping discs 54.

[0085] Figure 8 and 9 A third embodiment of a rotary cutting tool 10 is shown. Again, only the differences from the two embodiments described above will be discussed. Therefore, identical or corresponding parts are also provided with the same reference numerals.

[0086] In the rotary cutting tool 10 according to the third embodiment, the fixing unit 38 includes a fixing pin 62 .

[0087] The pin comprises a pin shank 64 and an axially adjoining pin head 66 .

[0088] The securing pin 62 extends substantially axially along the axis of rotation 8 .

[0089] Furthermore, the securing pin 62 consists of two securing pin halves 62a, 62b. These two securing pin halves are separated from one another by an axial gap 62c, which extends through the pin shank 64 and through the pin head 66. Consequently, the securing pin halves 62a, 62b are elastically deformable in the radial direction relative to the axis of rotation 8.

[0090] The pin shank 64 including the axial gap 62c has a substantially circular cross-section.

[0091] On the other hand, the pin head 66 , including the axial gap 62 c , has a substantially elliptical cross section. The cross section of the pin head 66 is configured so that all sides thereof radially protrude above the pin shank 64 .

[0092] Furthermore, an opening 68 assigned to the fixing pin 62 is provided on the cutting tip 14. This opening also extends substantially along the axis of rotation 8.

[0093] The opening 68 comprises a feed section 70 and an end section 72 . The end section 72 axially adjoins the feed section 70 in the direction towards the front face 36 of the cutting tip 14 .

[0094] The feed section 70 has a substantially oval cross-section configured such that the pin head 66 can be pushed through the feed section 70 .

[0095] Furthermore, the axial length of the feed section 70 corresponds substantially to the axial length of the pin shank 64 .

[0096] At least partially, the cross section of the end section 72 has an enlarged cross section relative to the feed section 70 .

[0097] The axial length of the end section 72 is substantially equal to the axial length of the pin head 66 or greater.

[0098] Thus, at least in those regions in which the cross section of the end section 72 radially exceeds the cross section of the feed section 70 , the end section 72 forms a third type of undercut 74 relative to the feed section 70 , which acts along the axis of rotation 8 , ie axially.

[0099] In the mounted state of the rotary cutting tool 10 , the securing pin 62 engages in the opening 68 . In doing so, the pin head 66 engages behind the third type of undercut 74 formed by the end section 72 and thus secures the cutting tip 14 to the shank 12 .

[0100] The mounting of the cutting tip 14 on the shank 12 is performed as follows.

[0101] First, the securing pin 62 and the cutting tip 14 are brought into a second rotational position, in which the cross-sections of the pin head 66 and the feed section 70 essentially coincide.

[0102] In this second rotational position, the securing pin 62 is inserted along the rotational axis 8 through the feed section 70 into the opening 68 . The cutting tip 14 then abuts the stop surface 44 of the shank 12 .

[0103] The cutting tip 14 is then moved into the first rotational position by rotating it relative to the shank 12 in the direction of rotation 26. This, on the one hand, brings the torque transmission geometry 24 into contact with the torque transmission counter-geometry 34. On the other hand, the pin head 66 is rotated within the end section 72 so that it engages in the undercut 74 of the third type.

[0104] In addition, the peripheral surface of the pin head 66 rests elastically against the peripheral surface of the end section 72 of the opening 68, whereby the two fixing pin halves 62a, 62b are elastically deformed radially inwards. Thus, the cutting tip 14 and the fixing pin 62 are also coupled in a friction-locking manner.

[0105] Overall, the cutting tip 14 is therefore securely held on the shank 12 .

[0106] The above embodiments of the rotary cutting tool 10 have been explained with the aid of a single locking geometry 16 cooperating with a single locking projection 32 of the cutting tip 14. However, it goes without saying that in all discussed embodiments, two such locking geometries 16 are provided, positioned diametrically opposite each other on the shank 12. Consequently, the cutting tip 14 also comprises two associated locking projections 32.

Claims

1. A rotary cutting tool (10) having a handle (12) having an axis of rotation (8), and a replaceable cutting tip (14) which is connectable to the handle (12), wherein the shank comprises a locking geometry (16) comprising a base body extending axially along the axis of rotation and a retaining finger extending from a cutting tip-side end of the base body in a circumferential direction relative to the base body, the retaining finger having a protruding section forming a first undercut and a second undercut, wherein the locking geometry further comprises a torque transmission geometry (24) oriented in the direction of rotation (26) and comprising a flat torque transmission surface and a curved torque transmission surface, and wherein the cutting tip includes a locking protrusion (32) having a torque transmission relative geometry (34) including a flat torque transmission relative surface and a curved torque transmission relative surface, in, In the installed state, the locking projection (32) of the cutting tip engages a first undercut of the shank to prevent the cutting tip from being pulled out of the shank along the axis of rotation, and the second undercut of the shank hinders rotation of the cutting tip relative to the shank in the direction of rotation and hinders lifting of the torque transmission relative geometry away from the torque transmission relative geometry that engages the torque transmission relative geometry (24). Characterized by a loading member (40) for holding the cutting tip (14) on the shank (12), wherein the loading member comprises a clamping screw for elastically deforming the holding finger in the direction of the base body so that the locking projection of the cutting tip is clamped between the holding finger and an axial stop surface on the shank.

2. The rotary cutting tool (10) according to claim 1, characterized in that The rotary cutting tool is a drill.

3. A rotary cutting tool comprising: a handle having an axis of rotation; a replaceable cutting tip configured to be coupled to the handle, wherein the shank comprises a locking geometry comprising a basic body extending axially along the rotation axis and a retaining finger extending from a cutting tip-side end of the basic body in a circumferential direction relative to the basic body, the retaining finger having a protruding section forming a first undercut and a second undercut, the locking geometry further comprising a torque transmission geometry oriented in the rotation direction and comprising a flat torque transmission surface and a curved torque transmission surface, wherein the cutting tip comprises a locking protrusion having a torque transmitting relative geometry comprising a flat torque transmitting relative surface and a curved torque transmitting relative surface, in, In the installed state, the locking projection of the cutting tip engages the first undercut of the shank to prevent the cutting tip from being pulled out of the shank along the rotational axis, the second undercut of the shank hinders rotation of the cutting tip relative to the shank in the rotational direction and hinders lifting of the torque transmitting opposing geometry away from the torque transmitting geometry, and abutting of the torque transmitting opposing geometry with the torque transmitting geometry; and A loading member for holding the cutting tip on the shank, wherein the loading member comprises a clamping disc which is arranged between the cutting tip and the shank such that in the mounted state of the cutting tip the retaining fingers of the shank are pressed axially against the locking projections of the cutting tip.

4. The rotary cutting tool (10) according to claim 3, characterized in that The clamping disk (54) is positioned on a side of the cutting tip (14) facing away from the retaining finger (20), and the clamping disk (54) includes a first support geometry (58) and a second support geometry (60) for positioning the cutting tip (14) on the shank (12).

5. The rotary cutting tool (10) according to claim 4, characterized in that A first support geometry (58) facing the shank (12) and a second support geometry (60) facing the cutting tip (14) are different.

6. The rotary cutting tool (10) according to claim 3, characterized in that The clamping disc (54) is a component separate from the shank (12) and the cutting tip (14), and in particular, the clamping disc (54) is replaceable.

7. The rotary cutting tool (10) according to claim 3, characterized in that The rotary cutting tool is a drill.

8. A rotary cutting tool comprising: a handle having an axis of rotation; a replaceable cutting tip configured to be coupled to the handle, wherein the shank comprises a locking geometry comprising a basic body extending axially along the rotation axis and a retaining finger extending from a cutting tip-side end of the basic body in a circumferential direction relative to the basic body, the retaining finger having a protruding section forming a first undercut and a second undercut, the locking geometry further comprising a torque transmission geometry oriented in the rotation direction and comprising a flat torque transmission surface and a curved torque transmission surface, wherein the cutting tip comprises a locking protrusion having a torque transmitting relative geometry comprising a flat torque transmitting relative surface and a curved torque transmitting relative surface, in, In the installed state, the locking projection of the cutting tip engages the first undercut of the shank to prevent the cutting tip from being pulled out of the shank along the rotational axis, the second undercut of the shank hinders rotation of the cutting tip relative to the shank in the rotational direction and hinders lifting of the torque transmitting opposing geometry away from the torque transmitting geometry, and abutting of the torque transmitting opposing geometry with the torque transmitting geometry; and a fixing unit for holding the cutting tip on the shank, wherein the fixing unit comprises a fixing pin and an opening associated with the fixing pin is provided on the cutting tip, wherein the fixing pin extends axially from the shank and engages in the opening in the mounted state of the cutting tip, wherein the fixing pin (62) comprises a pin shank (64) and a pin head (66), and the opening (68) has a third undercut (72), wherein the third undercut acts axially, and the pin head (66) is arranged inside the opening (68) in a first rotational position of the cutting tip (14) relative to the fixing pin (62) and engages in the third undercut (72) so that the cutting tip (14) is fixed to the shank (12) in the axial pull-out direction, The outer peripheral surface of the pin head (66) is elastically placed against the outer peripheral surface of the third undercut portion (72) of the opening.

9. The rotary cutting tool (10) according to claim 8, characterized in that The pin head (66) has an elliptical cross section, and the opening (68) of the cutting tip (14) includes a feed section (70) designed with a corresponding elliptical cross section, so that the pin head (66) can be axially inserted into the opening (68) in a second rotational position, wherein the second rotational position is different from the first rotational position.

10. The rotary cutting tool (10) according to claim 8, characterized in that The fixing pin (62) consists of two fixing pin halves (62a, 62b) separated by an axial gap (62c), wherein the fixing pin halves (62a, 62b) are elastically deformable in the radial direction.

11. The rotary cutting tool (10) according to claim 8, characterized in that The rotary cutting tool is a drill.

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