Abstract
The present invention relates to a chisel holder system comprising a milling chisel, a chisel holder and a clamping device, in particular a clamping screw. The present invention further relates to a milling drum and a ground milling machine having a chisel holder system.
Claims
1. A chisel holder system, comprising: a milling chisel; a chisel holder; and a clamping device, the milling chisel, comprising: a chisel head with a chisel tip, the chisel head widening in a head region away from the chisel tip along a longitudinal axis (E) of the milling chisel in a radial direction relative to the longitudinal axis (E); a contact region adjoining the head region and configured to contact the chisel holder; a shank region adjoining the contact region; and a clamping region adjoining the shank region, wherein the milling chisel has at least one of the following features in the clamping region: at least one clamping wedge with a chisel holder contact surface; or two shank legs which are spaced apart from each other in the radial direction relative to the longitudinal axis (E) of the milling chisel via a clamping slot; or an inclined sliding surface contacted by the clamping device and/or a guide recess in which the clamping device engages, the chisel holder, comprising: an end face-side milling chisel receiving opening; a shank receiving space adjoining the milling chisel receiving opening in the direction of an insertion axis (R) of the milling chisel and extending into the interior of the chisel holder; and a clamping device opening extending transversely to the insertion axis (R) of the shank receptacle, which provides an access connection from the outside of the chisel holder surrounding the insertion axis (R) to the receiving space and through which the clamping device can be inserted for fixing the milling chisel within the chisel holder.
2. The chisel holder system according to claim 1, wherein the milling chisel has at least one of the following features: the at least one clamping wedge has a greater radial extension (W) relative to the longitudinal axis (E) of the milling chisel than the shank region adjoining the at least one clamping wedge; the contact region has at least partially a contact cone tapering radially in a direction away from the chisel tip, the contact cone being formed in particular as a truncated cone; the at least one clamping wedge is arranged terminally in the longitudinal direction (E) of the milling chisel; the at least one clamping wedge has a contact surface extending obliquely to the longitudinal axis (E) of the milling chisel, the distance of the contact surface in the radial direction relative to the longitudinal axis (E) of the milling chisel increasing in a direction away from the chisel tip; or there are two clamping wedges positioned opposite one another in the radial direction.
3. The chisel holder system according to claim 1, wherein the clamping device is a clamping screw which has a screw thread (T) with a thread axis (B), the thread axis (B) and the longitudinal axis (E) of the milling chisel running obliquely or intersecting at an angle (W5) to one another.
4. The chisel holder system according to claim 3, wherein the clamping screw has a clamping cone on an end face relative to a screw axis (B) and a recess on the opposite end face for positive engagement of a screwing tool.
5. The chisel holder system according to claim 4, wherein the clamping screw comprises a cylindrical part which adjoins the clamping cone and in which the recess for positive engagement of a screwing tool is introduced on the end face, and in that the clamping cone and/or the cylindrical part has the screw thread in the form of an external thread, or in that one or both of the shank legs has a clamping thread for engagement of the clamping screw, such that the radial distance of the two shank legs radially relative to the longitudinal axis (E) of the milling chisel is at least partially increased during continued screwing-in movement of the clamping screw.
6. The chisel holder system according to claim 1, wherein the chisel holder has a clamping wedge receiving space which adjoins the shank receiving space in the direction of the insertion axis (R) and is configured to receive the at least one clamping wedge of the milling chisel, the clamping wedge receiving space having at least one subregion which is widened in radial direction with respect to the shank receiving space adjoining it against to the insertion direction.
7. The chisel holder system according to claim 1, wherein the chisel holder has a sleeve bottom with a bottom wall which closes off the interior space inside the chisel holder in the insertion direction (R) on an end face opposite the milling chisel receiving opening.
8. The chisel holder system according to claim 1, wherein the chisel holder has as connection openings to the outside environment of the interior of the chisel holder exclusively the end face-side milling chisel receiving opening and the clamping device opening extending transversely to the insertion axis (R) of the shank receptacle.
9. The chisel holder system according to claim 1, wherein the clamping device opening or the guide recess has a thread (T1).
10. A milling drum with at least one chisel holder system according to claim 1.
11. A ground milling machine, comprising a milling drum with at least one chisel holder system, the chisel holder system comprising: a milling chisel; a chisel holder; and a clamping device, the milling chisel, comprising: a chisel head with a chisel tip, the chisel head widening in a head region away from the chisel tip along a longitudinal axis (E) of the milling chisel in a radial direction relative to the longitudinal axis E; a contact region adjoining the head region and configured to contact the chisel holder; a shank region adjoining the contact region; and a clamping region adjoining the shank region, wherein the milling chisel has at least one of the following features in the clamping region: at least one clamping wedge with a chisel holder contact surface; or two shank legs which are spaced apart from each other in the radial direction relative to the longitudinal axis (E) of the milling chisel via a clamping slot; or an inclined sliding surface contacted by the clamping device and/or a guide recess in which the clamping device engages, the chisel holder, comprising: an end face-side milling chisel receiving opening; a shank receiving space adjoining the milling chisel receiving opening in the direction of an insertion axis (R) of the milling chisel and extending into the interior of the chisel holder; and a clamping device opening extending transversely to the insertion axis (R) of the shank receptacle, which provides an access connection from the outside of the chisel holder surrounding the insertion axis (R) to the receiving space and through which the clamping device can be inserted for fixing the milling chisel within the chisel holder.
12. The chisel holder system according to claim 1, wherein the clamping device comprises a clamping screw.
13. The chisel holder system according to claim 1, wherein the contact region directly adjoins the head region, wherein the shank region directly adjoins the contact region, and wherein the clamping region directly adjoins the shank region.
14. The chisel holder according to claim 1, wherein the chisel holder is essentially configured as a holder sleeve.
15. The chisel holder system according to claim 3, wherein the thread axis (B) and the longitudinal axis (E) of the milling chisel run perpendicularly to one another.
16. The chisel holder system according to claim 9, wherein the thread (T1) is an internal thread.
17. The milling drum according to claim 10, wherein the milling drum comprises a fine milling drum.
18. The ground milling machine according to claim 11, wherein the ground milling machine comprises a cold milling machine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0076] The present invention will be explained in more detail below by reference to the embodiment examples shown in the figures; wherein:
[0077] FIG. 1A shows a top view of a fine milling drum;
[0078] FIB. 1B shows a side view of the fine milling drum of FIG. 1A;
[0079] FIG. 2A shows a top view of another milling drum;
[0080] FIG. 2B shows a side view of the milling drum of FIG. 2A;
[0081] FIG. 3A shows an exploded view of a chisel holder system;
[0082] FIG. 3B shows a side view of the milling chisel of FIG. 3A;
[0083] FIG. 3C shows a side view of the milling chisel of FIG. 3A rotated by 90° about the longitudinal axis of the milling chisel in relation to the side view of FIG. 3B;
[0084] FIG. 3D shows a top view of the tip of the milling chisel of FIG. 3A;
[0085] FIG. 4A shows a cross-sectional view through the chisel holder system of FIG. 3A;
[0086] FIG. 4B shows a side view of the milling chisel of FIG. 3A rotated by 90° about the longitudinal axis of the milling chisel in relation to the cross-sectional view of FIG. 4A;
[0087] FIG. 5A shows the cross-sectional view of FIG. 4A with the milling chisel fixed in the chisel holder;
[0088] FIG. 5B shows the cross-sectional view of FIG. 4B with the milling chisel fixed in the chisel holder;
[0089] FIG. 6 is a flowchart of a method according to the present invention;
[0090] FIG. 7 shows a side view of a ground milling machine;
[0091] FIG. 8 shows an enlarged detail view of the region 48 of FIG. 5A;
[0092] FIG. 9A shows an oblique perspective view of an exploded view of an alternative embodiment of a chisel holder system;
[0093] FIG. 9B shows an oblique perspective view of the chisel holder system of FIG. 9A with the milling chisel fixed in the chisel holder and with an installation tool;
[0094] FIG. 9C shows a longitudinal cross-sectional view through the chisel holder system of FIGS. 9A and 9B with the milling chisel half inserted into the chisel holder;
[0095] FIG. 9D shows a longitudinal cross-sectional view rotated by 90° about the longitudinal axis or insertion axis compared to the longitudinal cross-sectional view in FIG. 9C;
[0096] FIG. 9E shows a longitudinal cross-sectional view through the chisel holder system of FIGS. 9A to 9D with the milling chisel in the rotated end position;
[0097] FIG. 9F shows a top view into the interior of the chisel holder of FIGS. 9A to 9E;
[0098] FIG. 9G shows a cross-sectional view transverse to the longitudinal axis or insertion axis along line III-III of FIG. 9E with the milling chisel in the insertion end position;
[0099] FIG. 9H shows a cross-sectional view transverse to the longitudinal axis or insertion axis along line III-III of FIG. 9E with the milling chisel in the rotated end position.
[0100] FIG. 10A shows an oblique perspective view of an exploded view of a further alternative embodiment of a chisel holder system;
[0101] FIG. 10B shows a longitudinal cross-sectional view through the chisel holder system of FIG. 10A with the milling chisel in the insertion end position;
[0102] FIG. 10C shows the longitudinal cross-sectional view of FIG. 10B with the clamping means tightened in the chisel holder and the milling chisel clamped; and
[0103] FIG. 11 shows a longitudinal cross-sectional view along the longitudinal axis according to an alternative embodiment of a milling chisel.
DETAILED DESCRIPTION OF THE INVENTION
[0104] Like components are designated by like reference numerals in the figures, although recurring components may not necessarily be designated throughout the figures.
[0105] FIG. 1A shows a milling drum 1 in a top view and FIG. 1B in a side view. In milling operation, the milling drum rotates about the rotation axis R, for example, driven by a suitable milling drum drive (not shown), for the connection of which a suitable drive flange 5 may be provided on the milling drum 1. An essential element of the milling drum 1 is a hollow-cylindrical support tube 3 (also referred to as a milling tube), the outer circumferential surface of which is occupied by a plurality of chisel holder systems 2. The chisel holder systems 2 each comprise a chisel holder 8 and a milling chisel 9. The chisel holder 8 may be directly attached to the outer circumferential surface of the support tube 3, as shown in the figures, or may be positioned and retained as a quick-change tool holder in a base member not shown, which in turn is directly connected to the support tube. FIG. 1A illustrates an arrangement of the chisel holder systems 2 in such a way that they run in helices directed toward the center of the milling drum. The side view of FIG. 1B illustrates that the individual chisel holder systems 2 are offset in the circumferential direction around the rotation axis R and are ideally arranged with gaps in between.
[0106] FIGS. 2A and 2B also show a milling drum 1, wherein in this milling drum 1, on the one hand, the milling width FB, i.e., the extension of the milling drum 1 along the rotation axis O, is smaller compared to the embodiment example according to FIGS. 1A and 1B. In addition, the arrangement of the chisel holder systems 2 differs from the previous embodiment in that there is no helical arrangement directed toward the center of the milling drum 1, but rather an arrangement in rows continuous over the entire milling drum width FB. However, the side view according to FIG. 2B also shows that the individual chisel tips of the chisel holder systems 2 are likewise arranged with gaps in between and offset to each other in the circumferential direction.
[0107] FIGS. 1A to 2B further illustrate that milling drums 1 may have additional elements on their outer circumferential surface in addition to the chisel holder systems 2, such as so-called ejectors 4 and/or edge protectors 6.
[0108] Further, the milling drums 1 of FIGS. 1A to 2B are so-called fine milling drums. These are characterized by a comparatively high density of chisel holder systems 2 on the outer circumferential surface of the milling drum 3. This results in small line distances, with a line distance denoting the distance in the axial direction of the rotation axis R of two adjacent cutting circles, as illustrated in more detail in FIG. 2A. FIG. 2A shows two milling chisels 9A and 9B adjacent to each other in the axial direction of the rotation axis. The chisel tips of these milling chisels 9A and 9B, which are not designated per se in FIG. 2A, each generate a cutting circle about the rotation axis O during rotation operation. The position of the two cutting circles in the direction of the rotation axis is marked 51 and S2 in FIG. 2A. The distance between these two cutting circles 51 and S2 in the direction of the rotation axis O is called the line spacing L. In fine milling drums, for example, this line spacing L is less than or equal to 8 millimeters.
[0109] FIG. 3A shows an exploded view of an embodiment example of a chisel holder system 2. The main components here are the chisel holder 8 and the milling chisel 9. In addition, a clamping means 10 is provided, in this case in the form of a clamping screw 11. The chisel holder system 2 may further comprise a sealing ring 12 and/or a sealing cap 13.
[0110] The milling chisel 9 can be inserted into the chisel holder 8, in particular along an insertion axis E, which, as in the present embodiment example, may correspond to a longitudinal axis R of the milling chisel 9. The longitudinal axis A of the milling chisel 9 corresponds to its longitudinal extension. The milling chisel 9 may be rotationally symmetrical and/or point-symmetrical with respect to said longitudinal axis A. The insertion axis R designates a movement axis along which the milling chisel can be inserted in a straight line from the position shown in FIG. 3A to an insertion end position in the chisel holder 8, for example, as part of an installation process when replacing the milling chisel. For this purpose, the chisel holder 8 has a milling chisel receiving opening 15 provided on the end face side in the direction of the insertion axis R, which is adjoined by an internal cavity not shown in FIG. 3 within the chisel holder 8, which in the present embodiment is configured as a holder sleeve, in particular comprising a shank receiving space and a clamping wedge receiving space. In the direction of the insertion axis R opposite the milling chisel opening 15, on the other hand, the chisel holder 8 is preferably closed and may have a sleeve bottom 59 for this purpose, for example.
[0111] The clamping means 10 in the present case refers to a device with the aid of which the milling chisel 9 can be fixed or clamped directly with respect to the chisel holder 8. The clamping means 10 can be inserted into the chisel holder 8 from the outside, in particular in such a way that it directly and immediately contacts the milling chisel 9 located in the chisel holder 8 or comes into positive engagement with it. For this purpose, a clamping means opening 14 is provided in the chisel holder 8, which can establish a connection between the cavity located inside the chisel holder 8 for receiving parts of the milling chisel 9 and the outside environment of the chisel holder 8 separate from the milling chisel receiving opening 15. A clamping means 10 may be the clamping screw 11 shown in FIG. 3A. However, other clamping devices may also be used. The clamping means 10, in particular the clamping screw 11, may have a clamping cone 16, in particular on an end face of a screw-in or longitudinal axis B, which is tapered toward a tip. In particular, the clamping cone 16 may be conical, especially with a rectilinear or uncurved cone surface or with an elliptical-paraboloidal cone surface. The clamping means 10 and in particular the clamping screw 11 may further comprise, on the side opposite the tip of the clamping cone 16, a part, in particular of cylindrical shape, with a recess 17 for tool engagement. The recess enables positive engagement of a screwing tool, for example in the form of a hexagon, a cross recess, etc. A shank part 18 may be provided between the recess 17 and the clamping cone 16 along the screw-in or longitudinal axis B of the clamping screw into the chisel holder 8 and/or the milling chisel 9. Said shank part may be cylindrical or also cone-shaped. Furthermore, threads, in particular screw threads, may be provided on the outer circumferential surface of the clamping cone 16, of the part carrying the recess for tool engagement 17 and/or of the shank part 18, which are provided for engagement in a suitable mating thread in the manner described below (in particular according to FIG. 8) as, for example, part of the clamping means opening 14 and/or of the milling chisel 9. The thread axis is coaxial with the screw-in or longitudinal axis B. Generally, various specific configurations of the clamping device 10 and in particular of the clamping screw 11 may be used. However, it has proved advantageous for the clamping screw 11 to be configured as a set screw, for example.
[0112] FIGS. 3B and 3C illustrate further details of the specific configuration of the milling chisel 9. The view in FIG. 3C is a view rotated by 90° about the longitudinal axis E compared to the view in FIG. 3B, and perpendicular to the longitudinal axis of the milling chisel 9. The relationship of the viewing directions is illustrated in more detail in FIG. 3D. FIG. 3B in this case corresponds to the side view from viewing direction II in FIG. 3D and FIG. 3C corresponds to viewing direction I of FIG. 3D.
[0113] In the present embodiment, essential elements of the milling chisel 9 are, for example, in immediate succession along the longitudinal axis E, a head region 19, a contact region 20 adjoining said head region in the direction away from the chisel tip, a shank region 21 adjoining said contact region in the direction away from the chisel tip, and a clamping region 22 adjoining said shank region in the direction away from the chisel tip. The individual regions are designated in more detail with regard to their respective axial extension in the direction of the longitudinal axis E in FIG. 3B and FIG. 3C. It should be emphasized that the ratios of the axial lengths of the individual sections to one another may vary. However, it is advantageous, as also shown in the present embodiment example, if the contact region 20 is larger in its axial extension than the clamping region 22 with respect to its axial extension, in particular by at least a factor of two and more particularly by at least a factor of 2.5. This applies regardless of the present embodiment example.
[0114] The head region 19 of the milling chisel 9 comprises a chisel head 23 with a chisel tip 24, which is tapered in the direction toward a chisel tip 24. The chisel head 23 may further include a chisel cap or wear protection cap 25. FIGS. 3B and 3C illustrate that the chisel head 23 is essentially configured in such a manner that it widens radially with respect to the longitudinal axis E in a direction away from the chisel tip 24 along the longitudinal axis E of the milling chisel. In other words, at least essential parts of the chisel head are preferably configured essentially as a cone, which also includes variants that have surface deformations in the head region, such as slot-like recesses, etc. In its entirety, the head region 19 essentially designates that part of the milling chisel 9 in the axial direction of the longitudinal axis E which is in direct contact with the ground material during milling operation, whether for milling or forwarding.
[0115] In contrast, the contact region 20 directly adjoining the head region 19, for example, designates that region of the milling chisel 9 which is essentially provided for, in particular direct, contact with the chisel holder 8, in particular in the interior of the milling chisel holder 8 in the direction of the insertion axis R behind the milling chisel receiving opening 15 (as explained in more detail below), and is functionally responsible in particular for the transfer of force from the milling chisel 9 to the chisel holder 8. In terms of its radial extension, this region is therefore also preferably smaller or narrower than the maximum radial extension of the head region 19 and recedes behind the latter in the radial direction. In particular, the contact region 20 may at least partially include a contact cone 26. The latter may be configured as a straight truncated cone with a linear circumferential surface line and a cone axis running coaxially to the longitudinal axis E, as illustrated in more detail by way of example in FIGS. 3B and 3C. In this case, the contact region 20 may be configured such that the contact cone 26 extends over essentially the entire contact region 20 in the direction of the longitudinal axis E. In particular, the outer circumferential surface of the contact cone 26 may extend at an angle K in a range of 5° to 50° and more particularly in a range of 10° to 30° to the longitudinal axis E of the milling chisel 9. Curved or otherwise deformed circumferential surface lines are also conceivable, as long as a section is obtained in which the milling chisel tapers away from the chisel tip 24 without transition and ideally evenly or continuously, as is the case with a cone, instead of tapering abruptly. In particular, the abrupt step between the head region and the contact region provided in the embodiment example, by which the radial extension of the milling chisel 9 is greatly reduced, is not part of the contact region. One aspect of the contact region according to the present invention is that it allows contact not only in the axial direction but also simultaneously in the radial direction, as is the case, for example, with the cone included in the embodiment example. This applies generally to configurations of a milling chisel according to the present invention and is not to be understood as being limited to the present embodiment example.
[0116] In the shank region 21 adjoining the contact region 20 along the longitudinal axis of the milling chisel 9 toward the rear, on the other hand, the milling chisel may be of essentially cylindrical design, in which case there may be two shank legs 28A and 28B in this region, which are spaced apart from one another in the radial direction via a clamping slot 29. The two shank legs 28A and 28B both end in the contact cone 26.
[0117] At the end of the clamping slot 29 located in the direction of the chisel tip 24, this slot may merge into a relief bore 30 running perpendicular to the longitudinal axis E. The relief bore 30 may be partially widened relative to the width of the clamping slot 29, i.e., the direct radial spacing of the two shank legs 28A and 28B, so that, as shown by way of example in the present embodiment example, a region of lower material thickness is obtained in the region of the relief bore 30 compared to the thickness of the two shank legs 28A and 28B in the radial direction. The relief bore 30 may be hollow-cylindrical. The longitudinal axis H of the relief bore 30 runs, for example, radially with respect to the longitudinal axis E of the milling chisel 9 and intersects it. Bending forces acting on the shank legs 28A and 28B, in particular in the direction of the shank legs 28A and 28B in or against the radial direction relative to the longitudinal axis E, therefore result in a defined relative movement on the one hand of the two shank legs 28A and 28B to each other and also relative to the rest of the milling chisel 9, in particular relative to the contact region 20. The bending movement thus obtained is indicated by the arrows P in FIG. 3C.
[0118] The shank region 21 may be essentially cylindrical in shape, interrupted only by the clamping slot 29. In particular, the diameter of the shank region 29, i.e., the distance of the outer circumferential surface of the shank legs 28A and 28B from the longitudinal axis E of the milling chisel 9, may be constant.
[0119] In a direction away from the chisel tip 24, the shank region 21 may be directly adjoined by the clamping region 22 along the longitudinal axis E. In the clamping region 22, as shown in the present embodiment, the milling chisel 9 may have, for example, two clamping wedges 31A and 31B, each on one of the two shank legs 28A and 28B. The clamping wedges 31A, 31B may partially protrude beyond the outer circumferential surface of the shank region 21 in a radial direction relative to the longitudinal axis E and may each have a wedge-shaped contact surface 32A, 32B in this region. The contact surfaces expand in the radial direction along the longitudinal axis E away from the chisel tip, i.e., increase with respect to their radial distance. The clamping wedges 31A and 31B thus each represent a wedge-shaped protrusion relative to the shank region 21, extending in a radial direction relative to the longitudinal axis E of the milling chisel 9. The clamping wedges 31A and 31B are not formed circumferentially around the longitudinal axis E of the milling chisel 9, but alternately in a segment-like manner in the circumferential direction around the longitudinal axis E. This means that, viewed in the circumferential direction, the radial extension of the clamping region 22 alternates between a maximum radial extension Wmax and a minimum radial extension Wmin. The shank region 21 and the adjoining clamping region 22 of the milling chisel 9 are thus essentially T-shaped overall. The minimum radial extension Wmin may correspond to the maximum diameter of the shank region 21. It is essential that at least one clamping wedge 31 is provided in the clamping region 22, which protrudes in radial direction relative to the longitudinal axis E or insertion axis R relative to the shank region 21. The protrusion obtained with the aid of the at least one clamping wedge 31 may be used in a manner described in more detail below to clamp the milling chisel 9 to the chisel holder 8 in a manner according to the present invention.
[0120] The clamping wedges 31A and 31B or at least the at least one clamping wedge 31 comprise the contact surface 32 extending obliquely to the longitudinal axis E with a circumferential surface line 35 which extends in particular at an angle G (FIG. 5B) in a range of greater than 20°, in particular greater than 35°, and/or smaller than 70°, in particular smaller than 55°, in the present embodiment, for example, approx. 45°, to the longitudinal axis E of the milling chisel 9. The radial distance of the outer circumferential surface of the respective clamping wedge from the longitudinal axis E increases in the direction away from the chisel tip 24 of the milling chisel 9. Overall, the milling chisel 9 thus comprises in the contact region 20 and in the clamping region 22 two contact surfaces extending, in a direction away from the chisel tip 24 of the milling chisel 9, in a wedge shape or in a counter-directional manner and obliquely to the longitudinal axis E (indicated in particular by the course of the circumferential surface lines 27 and 35), so that the milling chisel 9 as a whole has a constriction which at least partially surrounds the longitudinal axis E of the milling chisel and which may be formed by the contact cone 26 and the at least one clamping wedge 31 or the clamping wedges 31A and 31B. These two wedge-shaped contact surfaces, arranged one behind the other in the direction of the longitudinal axis E of the milling chisel 9 away from the chisel tip 24, are used in the manner described in more detail below to clamp the milling chisel 9 directly to the chisel holder 8.
[0121] The milling chisel 9 may further have an inclined sliding surface and/or guide recess 38, particularly in the region of the milling chisel shank and more particularly in the region of the shank legs 28A and 28B, which is provided for at least partial engagement with the clamping means 10. The purpose of this inclined sliding surface and/or guide recess 38 is, in particular, to apply a clamping force to the clamping region 22. Exemplary for this is the guide recess 38 (FIG. 3A) illustrated in the embodiment examples of FIGS. 3A to 3D, which is hollow cone-shaped and extends over the clamping slot 29 between the two clamping wedges 31A and 31B. In the specific embodiment example, two cone-shell-shaped recesses, which are located opposite and mirror-symmetrical to each other, are arranged for this purpose at the level of the clamping wedges 31A and 31B, which in their entirety form the guide recess 38 and which are provided for engagement of the clamping means 10. When the clamping device 10 is driven into this guide recess 38, this causes the two shank legs 28 to spread apart in the direction of arrow W (FIG. 3C).
[0122] The operating principle of the exemplary chisel holder system 2 described above is explained in more detail, in particular, by the cross-sectional views of FIGS. 4A, 4B, 5A and 5B. All of these figures represent longitudinal cross-sectional views through the milling chisel holder system 2 along the insertion axis R or longitudinal axis E, as shown in the exploded view of FIG. 3A. FIGS. 4A and 4B show a condition in which the milling chisel 9 is partially inserted into the chisel holder 8. In FIGS. 5A and 5B, on the other hand, the milling chisel 9 is in its end position, in which it is in a position clamped with the chisel holder 8. In FIG. 4A, the milling chisel holder system 2 is shown in a cross-sectional view according to section line II′, and in FIG. 4B it is shown in a cross-sectional view according to section line I′ of FIG. 3D. In FIGS. 5A and 5B, the milling chisel 9 is rotated relative to the chisel holder 8 by 90° about the insertion axis R and the longitudinal axis E, respectively. With respect to the chisel holder 8, FIG. 5A thus corresponds to section line II′ and FIG. 5B corresponds to section line I′ of FIG. 3D.
[0123] The chisel holder 8 may be configured as an essentially cylindrical sleeve having the milling chisel receiving opening 15 and a clamping means opening 14. The interior of the chisel holder 8 is marked 36. In the present embodiment example, said interior is preferably accessible exclusively from outside the chisel holder 8 via the milling chisel receiving opening 15 and the clamping means opening 14. In the direction of the insertion axis R, a conical contact space 37, a shank receiving space 33 and a clamping wedge receiving space 34 may successively adjoin the milling chisel receiving opening 15 within the chisel holder 8 in the interior space 36. The conical contact space 37 is at least partially complementary to the contact cone 26 of the milling chisel 9 and at least partially has a hollow cone-shaped or funnel-shaped inner circumferential surface which, in a direction away from the chisel receiving opening 15, tapers radially relative to the insertion axis R along the latter in a linear manner. The clamping wedge receiving space 34 has an essentially circular cross-section in a radial direction relative to the insertion axis R with a diameter D. In contrast, the shank receiving space 33 has a cross-section shaped as a rounded rectangle with a maximum diameter Cmax and a minimum diameter Cmin perpendicular thereto. The maximum diameter Cmax, for example, corresponds essentially to the diameter D in the clamping wedge receiving space 34. The minimum diameter Cmin, on the other hand, is smaller than both the maximum diameter Cmax and the diameter D in the clamping wedge receiving space 34. Thus, an undercut 58 is obtained overall in the clamping wedge receiving space 34 with respect to the shank receiving space 34, into which the at least one clamping wedge 31 or the clamping wedges 31A and 31B described above for the present embodiment example can be rotated for clamping the milling chisel 9 with respect to the chisel holder 8. The maximum diameter Cmax of the shank receiving space 33 is therefore also selected at least such that it is larger, ideally as minimally as possible, than the maximum extension Wmax of the milling chisel 9 in clamping region 22. The minimum diameter Cmin of the shank receiving space 33, on the other hand, is dimensioned such that it is smaller than the maximum radial extension Wmax of the clamping region 22 but at the same time, ideally as minimally as possible, larger than the minimum radial extension Wmin of the clamping region 22 of the milling chisel 9.
[0124] In the direction of the insertion axis E, the chisel holder 8 is closed at the end face on the side opposite the milling chisel receiving opening 15. Apart from the additionally provided clamping means opening 14, the receiving space inside the chisel holder 8 is thus essentially configured as a blind hole. The chisel holder 8 may comprise a total of exclusively two openings to the outside environment, via which the interior, in particular comprising the delimitation by the contact surface 55 for the contact cone 26 of the milling chisel 9, or the interior defined by this contact surface, or the conical contact space 37, the shank receiving space 33 and the clamping wedge receiving space 34, is connected to the outside environment.
[0125] The contact surface 55 with the circumferential surface line 56 is at least partially and in particular completely complementary to the contact region 26 or its circumferential surface line 27 (FIG. 5B). In contrast, the contact surfaces 39 in the clamping wedge receiving space 34, in particular with the circumferential surface line 57 (FIG. 4B), are formed at least partially complementary to the corresponding contact surfaces of the at least one clamping wedge 31 or of the two clamping wedges 31A and 31B of the milling chisel 9 (FIG. 5B).
[0126] Overall, as a comparison of FIGS. 4A and 4B in particular makes clear, the chisel holder 8 in the present embodiment example may, on the one hand, have a continuous constant radial extension in the shank receiving space 33 and in the clamping wedge receiving space 34 with respect to the insertion axis R of the chisel holder 8, as shown in FIG. 4A. Rotated by 90° about this insertion axis R, on the other hand, a radial constriction or tapering of the inner cavity of the chisel holder 8 may be provided, i.e., the radial width of the interior of the chisel holder 8, starting from the milling chisel receiving opening 15, initially tapers down to the minimum diameter Cmin and then widens again to the diameter D. This provides an undercut 58 in the clamping wedge receiving space 34, which can be used to clamp the milling chisel 9 in the chisel holder 8.
[0127] In the present embodiment example, the clamping means opening 14 is essentially hollow-cylindrical in shape and connects the interior 36 relative to the insertion axis R approximately at the level of the clamping wedge receiving space 34 on one side with the outside environment of the chisel holder 8 in the radial direction relative to the insertion axis R and thus perpendicular to this axis. With the aid of the clamping means opening 14, the clamping means 10 can thus be inserted transversely and in particular perpendicularly to the milling chisel receiving opening 15 and thus from the side of the chisel holder 8 in such a way that it projects at least with a tip region into the interior 36 and in particular at least partially into the clamping wedge receiving space 34 of the chisel holder 8.
[0128] Due to the above-described relative dimensioning on the one hand of the shank region 21 and the clamping region 22 of the milling chisel 9 and on the other hand of the shank receiving space 33 and the clamping wedge receiving space 34 of the chisel holder 8, the milling chisel 9 can thus only be inserted into the chisel holder 8 in two positions rotated by 180° to each other. If the milling chisel 9 is pushed further into the chisel holder 8 along the insertion axis R from the position shown in FIGS. 4A and 4B until the contact cone 26 rests against the inner circumferential surface of the conical contact space 37 of the chisel holder 8, it reaches its insertion end position. The milling chisel 9 then cannot be inserted further into the chisel holder 8 along the insertion axis R.
[0129] Following this, the milling chisel can be rotated about the insertion axis R by approximately 90° in order to rotate the at least one clamping wedge 31, more specifically the two clamping wedges 31A and 31B in the present embodiment example, into the undercut region 58 of the clamping wedge receiving space 34 of the chisel holder 8. Due to this rotating movement, the clamping wedges 31A and 31B, viewed in the direction of the insertion axis R, overlap the above-described taper between the shank receiving space 33 and the milling chisel receiving opening 15 or, viewed in the direction of the insertion axis R toward the chisel tip 24, engage behind the undercut 58, whereby a positive locking or blocking of the milling chisel 9 in the chisel holder 8 is obtained. Accordingly, the milling chisel 9 cannot be pulled out of the chisel holder 8 from this rotational position.
[0130] The chisel holder system 2 may further comprise a rotary stop acting between the milling chisel 9 and the chisel holder 8. Said rotary stop ensures that the milling chisel 9 moves from the insertion end position to its rotated end position in a defined manner. However, this may also be ensured additionally or alternatively by the mere fact that the clamping means 10 can only fix the milling chisel 9 in a defined position of the milling chisel relative to the chisel holder. This is the case, for example, if there is a thread on the milling chisel 9 into which the clamping means is to engage for clamping the milling chisel 9, in particular for spreading apart shank legs.
[0131] As a result of the above-described rotating movement, the guide recess 38 of the milling chisel 9 comes into a relative position opposite the clamping means opening 14 of the chisel holder 8, in particular in the radial direction relative to the insertion axis R. This allows the clamping means 10 to be introduced from outside the chisel holder 8 and to engage in the guide recess 38. Due to the cone-like configuration of the tip region of the clamping means 10 or the clamping screw 11, which is described in more detail below, continued penetration of the clamping means into the guide recess and thus in particular also into the region between the two shank legs results in the two shank legs 28A and 28B being pressed apart relative to each other. The clamping wedges 32A and 32B are thus both pressed away from each other simultaneously in the direction of arrow W, i.e., in the radial direction relative to the insertion axis. The force acting in the insertion direction of the clamping device 10 is thus converted into a spreading force that is essentially perpendicular to it. The spreading movement causes the contact surfaces 32A and 32B of the clamping wedges 31A and 31B within the clamping wedge receiving space 34 to be pressed against the contact surfaces 39 of the clamping wedge receiving space 34, which extend obliquely to the insertion axis R and are at least partially essentially complementary thereto. The shape of this contact surface 39, which is oblique to the rotation axis or the insertion axis R, ultimately enables this spreading force to be converted into a tensile force acting on the milling chisel 9 in the direction of the insertion axis R into the interior of the chisel holder 8. As a result, the milling chisel 9 is pulled further into the chisel holder 8 along the insertion axis R, i.e., the contact cone 26 is pulled with a clamping force against the inner circumferential surface 55 of the conical contact space 37 of the chisel holder 8. The milling chisel 9 thus pulls itself directly against the chisel holder 8 into a fixed, non-rotatable clamping end position. In this position, the milling chisel is non-rotatably fixed in the chisel holder 8 and is ready for milling operation.
[0132] Variations with regard to the configuration of the chisel holder system 2 described above according to the present invention are also possible with regard to the configuration of the engagement of the clamping means 10 in the chisel holder 8 and/or in the milling chisel 9. Various exemplary alternatives to this are explained in more detail with reference to the enlarged region 48 of FIG. 5A shown in FIG. 8. In the region of a screw head 49, which in particular may also have the recess 17 for tool engagement, the clamping means 10 configured as a clamping screw 11 may have an essentially cylindrical outer circumferential surface 50, which may be smooth-walled or in particular may also at least partially have an external thread (designated T1 in FIG. 8 as an example). This external thread has the thread axis running coaxially to the screw-in axis B. For this case, a suitable internal thread (also part of T1 in FIG. 8) may be provided in the region of the clamping means opening 14 of the chisel holder 8. This region is designated 51 in FIG. 8. In this case, the clamping means 10 thus engages the chisel holder 8 via a threaded engagement. Additionally or alternatively, the clamping means may have a cylindrical region offset in the longitudinal direction of the clamping means 10 from the screw head 49 toward the screw tip 53, for example, with a reduced diameter relative to the screw head 49 with respect to the one screw axis B. This region 52 may be smooth-walled or, at least partially, have an external thread (designated T2 in FIG. 8 as an example). The clamping means may further have, additionally or alternatively, in particular in the region of the clamping means tip 53 or in a region 54 forming the clamping means tip 53, a conical spreading cone section tapering in particular away from the recess 17 or the screw head 49. In other words, the tip is preferably cone-shaped. Said cone may also be smooth-walled or at least partially formed with an external thread (designated T3 in FIG. 8 as an example). For regions 51 and/or 54 of the clamping means 10, in particular of the clamping screw 11, regions 55, 56 of at least partially complementary configuration may be provided in the milling chisel 9, in particular at the level of the clamping region 22, which are configured for engagement by the regions 51 and/or 54 (and for this purpose may have, for example, complementary threads or at least thread sections). In this case, the region 55 is a hollow-cylindrical-shell-shaped recess in the facing region of the shank legs 28A and 28B. The region 56 is a hollow-cone-shell-shaped recess in the facing region of the shank legs 28A and 28B. Both the region 55 and, additionally or alternatively, the region 56 may thus at least partially have internal threads or internal thread sections extending around the screw-in axis B, which are provided at least partially complementary with respect to the corresponding mating thread(s) T2 and T3 in the regions 51 and/or 54 on the clamping means 10. The interaction of the regions 51 and/or 54 of the clamping means 10 with the regions 55 and/or 56 of the milling chisel 9 results in the thread engagement between the clamping means 10 and the milling chisel 9 in this case.
[0133] In particular, FIG. 5A illustrates the function of the sealing element or sealing cap 13. The latter is placed on the clamping device or clamping means from outside the chisel holder 8 and spans, in a hood-like manner, the clamping means 10 or its head region accessible from outside the chisel holder, shielding it from the outside environment. This prevents signs of wear on the clamping means 10 or prevents dirt and grime from clogging an existing opening for engagement of a screwing tool, such as a polygonal recess.
[0134] FIG. 5A further illustrates the operating principle of the sealing ring 12. Said sealing ring may extend annularly around the longitudinal axis E and/or the insertion axis R. It is clamped in the axial direction of the insertion axis E between a contact surface 44 of the chisel holder 9 extending in the radial direction relative to the insertion axis R and a mating contact surface 45 of the chisel holder 8 located at the level of the milling chisel receiving opening 15, or surrounding it, and extending in the radial direction relative to the insertion axis R. In this manner, the sealing ring 15 achieves a sealing effect, in particular for the milling chisel receiving opening 15, which in the present embodiment example is closed in particular by the milling chisel 9. The sealing ring 12 now improves this seal to the effect that an ingress of dirt particles and/or moisture, in particular into the gap between the milling chisel 9 and the chisel holder 8, is drastically reduced.
[0135] The cross-sectional views according to FIGS. 4A to 5B further illustrate an elementary structure of the milling chisel 9. In particular, it may comprise a base body 46 acting as a tie rod, more particularly a steel base body, especially a quenched and tempered steel base body, for example, made of spring steel, which as one solid piece preferably forms the complete contact region 20, including the contact cone 26, the shank region 21 and the clamping region 22, as well as an inner part of the head region 19. The head region 19 further preferably comprises a wear protection hood or chisel cap 25 placed on the base body 46. Said cap is connected to the base body 46 by brazing, for example, and forms an essentially conical wear protection structure on the outside which forms at least essential parts of the outer surface of the head region 19. In particular, the chisel cap 25 may be made of a hard metal to effectively counteract any wear that occurs. The chisel tip may be formed by the chisel cap 25. However, it is also possible to place a chisel tip 24 on the chisel cap 25 which differs in terms of material. This preferably concerns a chisel tip 24 having a PCD (polycrystalline diamond) material. Said chisel tip may in particular be connected to the chisel cap 25 by a soldering process, especially brazing. The above-described elements 46, 25 and 24 are thus firmly and non-detachably connected to one another, so that the milling chisel 9 as a whole constitutes a one-piece overall structure.
[0136] FIG. 6 now illustrates essential steps of a method according to the present invention for installing a milling chisel in a chisel holder. For the specific configuration of the milling chisel and the chisel holder, reference is also made in particular to the above-described exemplary configuration of the milling chisel 9 and the chisel holder 8 and the related disclosure.
[0137] An initial step 40 includes inserting the milling chisel into an interior of the chisel holder along an insertion axis. This can also be seen, for example, in FIGS. 3A, 4A and 4B. The milling chisel is inserted until reaching an insertion end position. The insertion end position thus designates the position in which the milling chisel cannot be inserted further along an insertion axis into the chisel holder. This end position may be achieved, for example, by a contact cone of the milling chisel contacting an at least partially complementary hollow cone-shaped contact surface within the interior of the chisel holder.
[0138] The insertion movement, in particular along the insertion axis R, is now followed by inserting the at least one clamping wedge of the milling chisel into a clamping wedge receiving space located inside the chisel holder according to step 41. This may be done in particular by rotating the milling chisel about the insertion axis R, in particular by at least approx. 90°, in order to rotate the clamping wedge into the clamping wedge receiving space. This brings the milling chisel into a clamping pre-position relative to the chisel holder, from which a subsequent introducing of a clamping means causes fixing of the milling chisel in the chisel holder according to step 42.
[0139] During said introducing of the clamping means according to step 42, in particular by screwing in a clamping screw as clamping means, a clamping force is exerted by the clamping means on the milling chisel. The clamping force causes the milling chisel to reach a clamping end position in which it is pressed with its at least one clamping wedge against an inner wall of the clamping wedge receiving space and, at the same time, is pulled into the chisel holder until contacting the chisel holder with a contact region adjoining the head region. The clamping force acting on the milling chisel with the aid of the clamping means serves in particular to produce a spreading apart of at least two shank legs, which are spaced apart from each other in the radial direction via a clamping slot, within the clamping wedge receiving space in radial direction relative to a longitudinal axis of the milling chisel. In particular, the spreading movement is perpendicular to the screw-in direction of the clamping device relative to the milling chisel. A screw-in axis along which the clamping means is screwed into the chisel holder and/or the milling chisel preferably runs obliquely or transversely, in particular perpendicularly, to the insertion axis of the milling chisel into the milling chisel holder.
[0140] Finally, FIG. 7 shows a ground milling machine 43, in the present embodiment example a cold milling machine, which is used for removing road pavements and/or road markings in the context of roadway rehabilitation. Such machines are known per se in the prior art. They comprise a milling drum 1 arranged within a milling drum box, which in working operation is rotatable about a rotation axis R running horizontally and transversely to the working direction A. Details of the configuration of such a milling drum have already been given for FIGS. 1A to 2B.
[0141] FIGS. 9A to 9H illustrate a further embodiment example of a chisel holder system 2 according to the present invention. In particular, the existing differences from the previously described embodiment example are highlighted below. In all other respects, reference is made to the explanations regarding the preceding embodiment example, in particular according to FIGS. 3A to 5B and 8.
[0142] The main difference in this embodiment example is an alternative configuration of the guide recess 38, which in this embodiment example does not extend between two shank legs 28A and 28B, but rather extends through the shank leg 28A and directed toward the second shank leg 28B. For this purpose, the clamping means opening 14 in the chisel holder 8 may have an internal thread for engagement of the clamping means 10, in particular the clamping means screw 11. Preferably, however, the guide recess 38 for positive engagement located entirely in the first shank leg 28A has an internal thread complementary to an external thread located on the clamping means screw 11. Further preferably, no internal thread is provided in the region of the clamping means opening 14 of the chisel holder 8. When the clamping means screw 11 is tightened, the two shank legs 28A and 28B are thereby subjected to a clamping force in opposite directions and are thus pressed apart in opposite directions in the radial direction relative to the longitudinal axis E and/or insertion axis R. If the chisel holder 8 does not have an internal thread in the clamping means opening 14, it cannot wear out even over several generations of milling chisels. Such a chisel holder 8 can therefore be used for comparatively long periods of time.
[0143] This embodiment also has the advantage that the clamping screw 11 can be inserted into the chisel holder 8 in an assembly in which it is already screwed into the first shank 28A and thus in a pre-assembled state, as shown, for example, in FIG. 9A. This means that the clamping screw 11 does not have to be subsequently passed through the clamping means opening 14 of the chisel holder 8. In this embodiment, the clamping means opening 14 serves as a passage for a suitable screwing tool. This greatly facilitates the process of replacing the milling chisel 9.
[0144] FIGS. 9C, 9D and 9E summarize in chronological order the installation process of the milling chisel in the chisel holder 8. Together with the clamping screw 11, these form an assembly unit 47, which may also be traded as a whole in this form. With regard to the viewing perspective, the longitudinal view of FIG. 9C is rotated by 90° compared to the longitudinal view of FIG. 9D. With regard to the viewing perspective, FIG. 9C corresponds to section line II′ of FIG. 3D and FIG. 9D corresponds to section line I′ of FIG. 3D. In particular, FIG. 9D illustrates that the clamping means 10 is dimensioned with respect to its axial extension in the direction of its screw-in axis B in such a way that it is free of protrusions with respect to the maximum radial extension of the clamping wedge 31A. The radial interior diameter Cmin is accordingly larger than the axial extension of the clamping means 10. During the insertion of the milling chisel 9 into the chisel holder 8, the screw-in axis B and the clamping means opening 14 thus run in different radial directions with respect to the longitudinal axis E and/or insertion axis R. In FIG. 9E, after the milling chisel 9 has been pushed into its insertion end position, it is rotated by 90° relative to the chisel holder 8, whereby the clamping means 10 or the screw-in axis B comes into alignment with the clamping means opening 14. If the clamping means 10, in particular the clamping screw 11, is now further tightened in the direction toward the shank leg 28B, the clamping means 10 presses the second shank leg 28B and the first shank leg 28A (provided that an internal thread is provided there in which the clamping means 10 engages) apart in radial direction relative to the longitudinal axis E and/or insertion axis R and thus presses the two clamping wedges 31A and 31B radially into the clamping wedge receiving space 34. The contact surfaces 32A and 32B of the clamping wedges 31A and 31B, which are oblique relative to the longitudinal axis E and/or insertion axis R (as already described above), thus come into contact with the at least partially complementary contact surfaces 39 of the undercut 58. In this manner, a pulling effect is exerted on the milling chisel 9 in the insertion direction of the same into the chisel holder 8 and thus the milling chisel 9 is fixed with its contact cone 26 in the clamping region 22 in the chisel holder 8.
[0145] FIGS. 9F, 9G and 9H further illustrate this effect and the configuration of the chisel holder 8. The top view of the interior of the chisel holder 8 according to FIG. 9F first illustrates the configuration of the insertion opening for the milling chisel 9 in the form of a rounded rectangle with the maximum diameter Cmax and, perpendicular to this, the minimum diameter Cmin of the shank receiving space 33. Dashed lines in FIG. 9F further indicate the radial circumference of undercut 58. Said undercut surrounds the longitudinal axis E and/or insertion axis R in a circular manner and, in the region of the minimum diameter Cmin of the shank receiving space 33, forms a free space that undercuts the shank receiving space 33 in a radial outward direction relative to the longitudinal axis E and/or insertion axis R. The clamping wedges 31 are rotated into this free space in the manner described above, as further illustrated by a comparison of FIGS. 9G and 9H. Both figures show a cross-sectional view transverse to the longitudinal axis E and/or insertion axis R along section line III of FIG. 9E. In FIG. 9G, the milling chisel 9 is in the insertion end position. In FIG. 9H, on the other hand, starting from FIG. 9G, the milling chisel is rotated by 90° about the longitudinal axis E and/or insertion axis R and is accordingly in its clamping end position (in particular with the clamping screw 11 tightened). For further clarification, FIGS. 9G and 9H show the clamping means opening 14 concealed by the chisel holder 8 in those views, and the course of the screw-in axis B.
[0146] Generally, it is further possible for the shank receiving space 33 to have one or more insertion guides, for example threading grooves 65, extending in particular parallel to the longitudinal axis E and/or insertion axis R. These guides may be longitudinal expansions introduced into the shank receiving space 33, in which a complementary region of the milling chisel 9 can positively engage. The insertion guides, in particular threading grooves 65, extend in this case, for example, from the conical contact space 37 through the entire shank receiving space 33 or only through the entire shank receiving space in the axial direction relative to the longitudinal axis E and/or insertion axis R. This can ensure, for example, that the milling chisel 9 can be inserted into the chisel holder 8 exclusively from a rotational position relative to the chisel holder 8. This can facilitate proper alignment, particularly of the clamping means opening 14 relative to the clamping means 10 and/or the guide recess 38. This is achieved by the positive non-rotatable fixing about the longitudinal axis E and/or insertion axis R achieved with the aid of the insertion guide.
[0147] FIG. 9B further shows a milling chisel rotating tool 60, with the aid of which in particular the rotary movement of the milling chisel 9 about the insertion axis R and/or the longitudinal axis E for penetration of the clamping wedge or wedges 31, 31A, 31B into the region of the undercut 58 can be facilitated. For this purpose, the milling chisel rotating tool 60 is configured for positive engagement with the head region 19 of the milling chisel 9, wherein the positive engagement is to be provided in the circumferential about the insertion axis R and/or the longitudinal axis E. For this purpose, one or more protrusions 61A and/or recesses 61B may be provided in the outer circumferential surface of the chisel head 23, in particular of the chisel cap 25. In the region of a protrusion 61A, the outer circumferential surface is offset outward in the radial direction relative to the insertion axis R and/or the longitudinal axis E relative to a recess 61B, in particular at the same axial level relative to E and/or R. Protrusion 41A and recess 61B thus form one or more steps in the circumferential direction relative to the insertion axis R and/or the longitudinal axis E. The protrusions 61A and/or recesses 61B may taper with respect to their maximum radial extension along the insertion axis R and/or the longitudinal axis E in the axial direction toward the chisel tip.
[0148] The milling chisel rotating tool 60 may include at least one engagement protrusion and/or recess 62A, 62B. The at least one engagement protrusion and/or recess 62A, 62B is a device configured for at least partially complementary engagement with the tool engagement means, in particular comprising at least one protrusion 61A and/or recess 61B. The engagement takes place in such a way that a positive fit is achieved in the circumferential direction about the longitudinal axis E and/or insertion axis R of the milling chisel 9 when the milling chisel rotating tool engages the tool engagement means. For this purpose, the milling chisel rotating tool 60 may have an annular tool region 63, on the inner circumferential ring surface of which the engagement protrusions 62A and engagement recesses 62B are arranged alternately and circumferentially, in particular at a same angular distance from one another. The angular distances are preferably complementary to the angular distances of the protrusions 61A and recesses 61B arranged alternately around the chisel tip 23. Coming from the chisel tip 24, the milling chisel rotating tool 60 can thus be pushed onto the chisel head 23, in particular the chisel cap 25, so that it engages around the chisel head 23 from the outside, the engagement protrusions 62A engaging in the recesses 61B for this purpose and the engagement recesses 62B engaging around the protrusions 61A. As a result, a plurality of positive fits are obtained in the circumferential direction relative to the insertion axis R and/or the longitudinal axis E.
[0149] To facilitate rotational movement of the milling chisel rotating tool 60, it may include a rotation lever 64 adjoining the tool region 63 and protruding therefrom to one side. Here, too, however, a variety of alternative modified embodiments are conceivable. In particular, the tool region 63 may also be formed, for example, by a tool sleeve or the like, for example, to enable a rotary drive via a motor-driven actuator, for example pneumatic, hydraulic or electric.
[0150] Another general possibility for the construction of the milling chisel 9, which is independent of the structure and mode of operation of the present chisel holder system 2, is also illustrated in more detail in particular in FIGS. 9C, 9D and 9E. The special feature is that a cavity 66 is provided between the chisel cap 25, which is preferably made of a hard metal comprising, inter alia, tungsten carbide and/or cobalt as a component, and the base body 46, which is connected to the chisel cap 25 and in particular also comprises the chisel shank, as described above. This cavity may be surrounded exclusively by the chisel cap 25 and the base body 46. Thus, the chisel cap 25 is in direct contact with the base body 46 essentially via an annular contact surface 67 (and not over the entire surface). This immediate contact region between the chisel cap 25 and the base body 46 may preferably be used to solder these two components together. It is also possible to use boron nitride, for example, either in the chisel tip or the chisel cap.
[0151] In order to ensure correct relative alignment of the chisel cap 25 to the base body 46, in particular during the manufacturing process, a positioning aid 68 may preferably be provided on the base body 46. The positioning aid 68 may be configured such that it brings causes an unambiguous relative alignment of these two components with respect to one another, acting in a positive-fitting manner in the radial and/or axial direction with respect to the insertion axis R and/or the longitudinal axis E. In the present embodiment example, for example, a chamfer 69 is provided for this purpose, which runs around the insertion axis R and/or the longitudinal axis E on the base body 46 on the outer surface facing the chisel cap 25, in particular in an annular manner. The chamfer 69 has a circumferential surface conically tapering toward the chisel tip, which facilitates centering in the sense of pre-adjustment of the chisel cap 25 relative to the base body 46.
[0152] FIGS. 10A, 10B and 10 C illustrate another embodiment example of a chisel holder system 2 according to the present invention. In particular, the existing differences from the previously described embodiment examples are highlighted below. In all other respects, reference is made to the explanations regarding the preceding embodiment examples, in particular according to FIGS. 3A to 5B and 8 as well as 9A to 9H.
[0153] The special feature of the embodiment example shown in FIGS. 10A, 10B and 10C is that, in contrast to the previous embodiment examples, no clamping wedge is provided on the milling chisel 9 and thus no clamping wedge receiving space with a corresponding undercut is provided in the chisel holder. In the shank part 18, on the other hand, a bore is provided in the clamping region 22, in particular in the form of a through bore, which corresponds functionally to the guide recess 38. To fix the milling chisel 9 in the chisel holder 8, the milling chisel 9 is inserted into the chisel holder 8 along the insertion axis R and/or the longitudinal axis E until it reaches its insertion end position. The milling chisel 9 is now rotated to a position in which the guide recess 38 comes into an aligned position with respect to the clamping means opening 14 located in the chisel holder 8. After that, the clamping means 10, for example cone-shaped, is inserted into the clamping means opening 14 from outside the chisel holder 8. This can be done to the extent that the clamping means 10 completely passes through the chisel shank along the screw-in axis B and enters an internal thread located in the interior of the chisel holder 8 opposite the clamping means opening 14, which may, for example, be part of a blind hole or even a bore open to the outside. Additionally or alternatively, the clamping means opening 14 may likewise have an internal thread for threaded engagement by the clamping means 10. It is now essential that the guide recess 38 is configured, for example, as a conical through bore whose longitudinal axis or conical axis runs obliquely and, in particular, radially relative to the insertion axis R and/or longitudinal axis E. When the clamping device 10 is screwed in, the clamping device sliding on the inside of the guide recess 38 causes a tensile force on the milling chisel 9 via this cone recess, via which the contact cone 26 is pulled against the conical contact surface of the conical contact space 37.
[0154] It is possible to provide this embodiment example with shank legs 28 in the manner already described above. However, it is also possible to use a continuous shank and thus to dispense in particular with the provision of a clamping slot 29.
[0155] FIG. 11 illustrates another aspect of the present invention concerning the configuration of the chisel cap 25 and the base body 46. In this embodiment of the present invention, the cavity 66 may be enclosed by the chisel cap 25 and the base body 46. This cavity takes up a relatively large proportion of the volume of the milling chisel 9 and is intended to also be present as a hollow volume during milling operation of the milling chisels 9. In particular, the total volume of the cavity 66 significantly exceeds solder reservoirs used in the connection of two metal parts. The cavity 66 is actually hollow and not filled by any solid material. The cavity has an extension EL in the direction of the longitudinal axis E of the milling chisel 9 and an extension ER in the radial direction relative to the longitudinal axis E of the milling chisel 9. The radial extension ER becomes smaller from the maximum radial extension ER formed at the bottom of the cavity 66 by the axial lower end of the base body toward the chisel tip, since the frustoconical radial outer wall of the cavity formed by the chisel cap is inclined relative to the longitudinal axis E of the milling chisel by an angle W1 which is preferably smaller than 35°, in particular smaller than 30°, irrespective of the specific embodiment example. Regardless of the specific embodiment example, the maximum radial extension ER of the cavity 66 is greater than the extension EL of the cavity 66 in the direction of the longitudinal axis E. In the direction toward the chisel tip, or upward, the cavity 66 is delimited by a head roof 71 formed by the chisel cap 25. In the direction of the longitudinal axis E away from the chisel tip, or downward, the cavity is delimited by a bottom region 72 formed by the chisel base body 46. The head roof 71 and the bottom region 72 may both be circular disc-shaped and run parallel to one another. The angle W4 between the cone-shaped inner circumferential surface of the cavity 66 and the essentially planar head roof is preferably greater than 90°, particularly preferably greater than 100° and/or less than 150°, preferably less than 140°.
[0156] The chisel cap 25 has an extension EK in the direction of the longitudinal axis E of the milling chisel 9. The cavity 66 is now formed with such a spatial extension that it extends with its axial extension EL over at least 50% of the axial extension EK to the chisel cap.
[0157] The present embodiment example further shows a configuration of the contact region between the chisel cap 25 and the chisel base body 46. In contrast to the radially planar configuration of the contact region, as shown in the preceding FIGS. 9C to 9E, the contact surface between these two elements is preferably complementarily conical in shape. For this purpose, in its end region facing away from the chisel tip, the chisel cap has a radially outer circumferential contact surface 67 in the form of a cone, which is oriented at an angle W2 in the direction toward the chisel tip and completely uniformly surrounds the longitudinal axis and tapers away from the chisel tip in the direction of the longitudinal axis E. Complementary to this, the base body has a receiving surface 70 in its outer region in the radial direction relative to the longitudinal axis E, which, in a direction away from the chisel tip to the rear, tapers in a cone or funnel shape toward the longitudinal axis E. In this manner, a positive lock is obtained between the chisel cap and the chisel base body, which acts in the radial direction relative to the longitudinal axis E and is complementary to each other in the direct contact region, which not only facilitates assembly, but at the same time enables particularly efficient transfer of forces introduced into the chisel tip during milling operation, as shown here with the arrows P1, P2 and P3.
[0158] The contact region between the chisel cap 25 and the chisel base body 46 comprises an axial extension EB in the direction of the longitudinal axis E of the milling chisel 9. Toward the chisel tip, this region EB is overhung by the cavity, i.e., the cavity protrudes beyond the region EB in a direction toward the chisel tip. The radial extension EC of the contact region may be configured, as shown in FIG. 11, such that the contact region is located outside in the radial direction relative to the contact cone 26.
[0159] Another important feature of the embodiment shown in FIG. 11 is the optional configuration of the chisel cap 26 such that it projects beyond the complete chisel base body in the radial direction relative to the longitudinal axis E of the milling chisel or at least ends flush with it. In this manner, the chisel cap effectively protects the region of the milling chisel coming from the chisel tip and in the direction of the longitudinal axis E.
[0160] In the transition region between the bottom surface 72 and the receiving surface 70 or the contact region between the chisel cap 25 and the chisel base body 46, the chisel base body comprises a depression relative to the bottom surface 72 in the form of an annular groove 73. This annular groove 73, which runs around the longitudinal axis E, makes it easier to install the protective cap 25 on the chisel base body, preferably by means of a soldering process.
[0161] In the above-described contact region between the chisel cap 25 and the chisel base body 46, the chisel cap 25 is preferably attached to the chisel base body by means of a soldered connection.
