EP2766571A2

EP2766571A2 - Shank-type pick and holder

Info

Publication number: EP2766571A2
Application number: EP12780128.0A
Authority: EP
Inventors: Thomas Allgaier; Thomas Lehnert; Markus Roth
Original assignee: Wirtgen GmbH; Betek GmbH and Co KG
Current assignee: Wirtgen GmbH; Betek GmbH and Co KG
Priority date: 2011-10-11
Filing date: 2012-10-11
Publication date: 2014-08-20
Also published as: WO2013053811A3; CN104024576B; CN104024576A; US20140217806A1; WO2013053811A2; US9222354B2

Abstract

The invention relates to a tool system comprising a tool holder and a shank tool, the tool holder having a tool receiving opening with a first and a second diameter region which lead into one another via a transition section (narrowing) and a tool shank of the shank tool has a first and a second cross-sectional region which lead into one another via a transition section. To achieve a design for a tool system of this type that is optimised in terms of wear, the transition sections of the shank tool and the tool holder are interspaced in the direction of the central longitudinal axis of the shank tool to form a repositioning area.

Description

Tooling system

The invention relates to a tool system comprising a bit holder and a shank bit, wherein the bit holder has a bit receptacle having a first and a second diameter portion, which are merged into each other via a transition section, and wherein a bit shank of the Schaftmeißels a first and a second cross-sectional area which are merged into one another via a transition section.

Such a tool system is known from DE 33 07 895 A1. It is used for the processing of seams in mining but also for the processing of soil surfaces, for example. Road coverings. The shank bit has a chisel head and a chisel shank connected thereto. The drill collar is axially captive and freely rotatable around its central longitudinal axis secured in the bit holder of the chisel holder. Here, a circlip is used, which is inserted into a circumferential groove of both the chisel and the chisel holder. The Impingement has a first cylindrical portion and connected thereto a second cylindrical portion. The two cylindrical sections are merged into one another via a transition section. In the region of the second cylindrical portion, the circumferential groove for the securing element is incorporated. The chisel holder is provided corresponding to the chisel shank in the area of the chisel holder with two coaxial holes of different diameters. These two holes are also merged via a transition section into each other. The shank bit is held within the bit receptacle with a slight axial movement. A valve element, which is mounted in the bit holder, presses with a plunger on the free shank end of the shank bit. As a result, the shank bit is held in a first pretensioning position in which the chisel head is at a distance from a counter surface of the chisel holder with a support surface. If the shank bit is now pushed axially into the bit holder, the valve element is actuated and a flushing device is triggered. In the inserted state, the two transition sections of the bit holder and the shank bit sit on each other. This operating state occurs when the shank bit comes into contact with the substrate to be processed. Then also the shank chisel rotates within the chisel holder. On the one hand, the two transitional sections grind together and on the other hand the Meißeikopf grinds with its support surface on the counter surface of the chisel holder. As a result of these movements wear of the chisel holder is effected, which quickly leads to malfunction of the overall system, in particular, the shank bit can grind in such a way that it is blocked in the bit holder and then no longer freely rotatable. The consequence of this is that the shank bit is worn unevenly and therefore can not be used optimally over its entire period of wear.

A similar tool configuration is known from DE 26 30 276. For the purpose of a wear-optimized design of the tool system, it is necessary that the bit holder the life of a variety of Schaftekißeln survives. It is an object of the invention to provide a tool system of the type mentioned, which is designed wear-optimized.

This object is achieved in that the transition sections of the shank bit and the chisel holder are arranged spaced from one another in the direction of the central longitudinal axis of the shank bit to form a Nachsetzraums.

Contrary to the prior art according to DE 33 07 895 A1, the invention therefore follows a different path, according to which the transition sections are no longer in overlap in the axial direction, but are spaced apart. In this tool system, the inevitable wear of the bit holder is also caused due to the rotation of a support surface of the shank bit on a mating surface of the bit holder. This results in a length wear on the bit holder. Due to the spacing of the transition sections, the shank bit may progressively insert into the bit receptacle. The Nachsetzraum guaranteed that the transition sections do not come into contact. This preserves the free rotation of the shank bit. In this way, a variety of shank bits can be driven on the bit holder until the bit holder reaches its wear limit. This wear limit can then, for example, be given by the fact that, after a large number of bit changes, the outer contour of the bit holder is worn due to the aggressive attack of removed material or, finally, that the transition sections are seated on each other due to considerable length wear of the bit holder. According to a preferred variant of the invention, it is provided that the bit holder has a bearing surface on which the Schaftmeißei with a support surface of its chisel head is indirectly or directly supported. The chisel head is defined on the support surface, deposited during operation, and in this function position the transition sections are at a distance from one another. Thus, the length wear on the bit holder is generated at a predetermined location. The chisel head can be supported over a large area relative to the chisel holder, so that a stable power dissipation is possible. The chisel head can either be stored directly on the chisel holder or it is conceivable that the chisel head is supported with the interposition of an element, for example. A wear protection against the support surface of the chisel holder.

In order to obtain a reliable pivot bearing, it can be provided according to a variant of the invention that the first and the second cross-sectional area of the bit shank are formed by a first and a second cylindrical area, wherein the first cylindrical area has a diameter in the range between 18 mm and 30 mm and an extension in the direction of the central longitudinal axis of the Meißischeaft less than or equal to 30 mm. In this dimensioning of the first cylindrical portion results in a stable shaft guide. During the machining attack, forces act obliquely to the central longitudinal axis of the shank bit. This results in a bearing hole in the contact area of the first cylindrical section with the bit receptacle. The above-described dimensioning of the first cylindrical portion guarantees optimized removal of the forces, wherein the pending surface pressures are minimized. At the same time, a low friction wear is guaranteed in the area of the areas of the bit receptacle forming the pivot bearing. Such a design of a tool system is designed especially optimized for use in road construction. According to a preferred variant of the invention, the transition sections should be arranged spaced from each other in the range between at least 4 mm and a maximum of 20 mm. With a spacing of 4 mm, sufficient change cycles of the shank bit can be achieved if the tool system is designed to machine a soft ground. A spacing of less than or equal to 20 mm is required if a particularly hard ground, for example a concrete pavement, is to be removed.

Particularly preferably, the bit receptacle is formed by an insert consisting of hard material. The insert is mounted in an interior of the chisel holder. Such an insert guarantees a high resistance to fretting. It therefore allows a variety of tool change cycles. The chisel holder itself can therefore wear and cost-optimized consist of a steel material in which the insert is installed.

Reliable functioning of the tool system can be achieved, in particular, if provision is made for a rotary bearing and / or a sliding guide with the first cross-sectional area of the drill collar and the first diameter area of the bit receptacle and / or with the second cross-sectional area of the drill collar and the second diameter area Direction of action is formed in the direction of the central longitudinal axis of the Schaftmeißels. About the pivot bearing, the reliable rotation behavior of the shank bit can be maintained. The sliding guide guarantees a continuous repositioning of the shank bit in the Nachsetzraum.

If it is provided that the shank chisel has a securing element which is adjustable in the direction of the central longitudinal axis of the shank bit along a sliding guide of the chisel holder, then on the one hand a simple assembly and disassembly is possible. Assembly of the shank bit also possible in rough construction site operation. In addition, this results in a reliable fixation of the shank bit in the chisel holder. The sliding guide can be formed by the first and / or the second diameter region of the bit holder.

According to a preferred variant of the invention it can be provided that the securing element has a resilient clamping part, which at least partially surrounds a Lagerauf-, and in that the clamping part indirectly or directly radially outside fastening sections are connected, which are arranged spaced apart in the circumferential direction. This refinement of a securing element has the advantage over a securing element with an annular outer contour that the separate fastening sections can bear better against the inner wall of the bit receptacle, whereby in particular fastening tolerances or abrasion-related wear of the bit receptacle can be compensated. The fastening sections have a crust-like shape and thus guarantee a secure hold. The securing element itself can effect a good pivotal mounting of the Schaftmeißeis with the bearing seat of the tensioned egg.

An inventive tool system may also be characterized in that the drill collar at its free end with a collar or dgi. End section closes, and that the bit holder has subsequent to the Meißeiaufnahme an opening portion into which the collar or the like. End section can be added. With the arrangement of the opening portion in the field of chisel holder a compact design is possible. The collar or the like. End section is also not available from the chisel holder, when the Schaftmeißei puts into the Nachsetzraum. Thus, the shank bit is always secured and protected accommodated in the bit holder Here, the opening portion of a further function can be assigned by having an accessible from the bit holder back forth expulsion opening. The discharge opening provides access to the free end of the chisel shaft. An expelling tool can thus be attached to the shaft end and a worn shank bit can be expelled from the bit holder.

A further optimization of the tool system is created in that the bit holder has a plug-in projection for interchangeable mounting in a base part. As a result, a further verschieißoptimierte interpretation of the tool system is possible. In this case, the base part form the coupling piece to the rotational body of the road milling machine or the like. Construction Machinery. The base part can be designed so that it survives several cycles of change of a chisel holder. It is a quick and easy replacement of the bit holder with the plug approach possible. This can, for example, with a clamping screw, which acts on a support surface of the drill collar in a socket of the base part are clamped.

The invention will be explained in more detail below with reference to an embodiment shown in the drawings. Show it:

Figure 1 shows a shank chisel in side view and partly in section;

Figure 2 in side view a combination consisting of a bit holder and the shank bit shown in Figure 1;

FIG. 3 shows a detail of the representation according to FIG. 2 in vertical section;

FIG. 4 shows a securing element in plan view; Figure 5 shows the fuse element according to Figure 4 in side view and in

Section V-V according to Figure 4; Figure 6 shows the securing element according to Figures 4 and 5 in a perspective view;

Figure 7 shows a further embodiment variant of a fuse element in plan view;

FIG. 8 shows the securing element according to FIG. 7 along the section line marked Vltl-VIIi in FIG. 7;

Figures 9 and 10, the securing element according to Figures 7 and 8 in perspective;

Figure 11 shows an insert for mounting in the bit holder according to Figures 2 and 3 in side view and in vertical section; Figure 12 shows an alternative embodiment of a shank bit side view;

Fig. 13 is a securing element for the shank bit gem. Fig. 12 in side view and in section along the marked in Fig. 14 with XIII - XIII cutting profile and

Fig. 14 according to the fuse element. Fig. 13 in plan view. FIG. 1 shows a shank bit 10 having a drill shank 11 and an edged head 12 formed thereon. The drill shank 11 is designed as a stepped shank and has a first cylindrical section 11.1 which is transferred via a truncated cone-shaped transition section 11.2 into a second cylindrical section 11.3. goes, in the region of the second cylindrical portion 11.3 is a fuse holder 11.4 provided in the form of a circumferential groove. At the end, this securing receptacle is bounded 11.4 by a covenant 1.5. The first cylindrical section 11. 1 directly adjoins a support surface 12. 5 of the chisel head 12 via a rounding transition or alternatively via a frustoconical transition section. When using a truncated cone-shaped transition section, a stress-optimized contouring with a cone angle of 45 ° and an extension in the direction of the Mitteilängsachse M of the drill collar 11 of less than 4 mm has proven to be advantageous. The support surface 12.5 is annular and is formed by a collar-shaped support portion 12.1. The chisel head 12, starting from the support section 12.1, merges via a taper 12.2 with a concave geometry into a discharge surface 12.3. The discharge surface 12.3 is presently formed truncated cone, but may also be designed, for example, cylindrical or concave. At its, the drill collar 11 facing away from the end of the chisel head 12 carries a cutting element 13 in a cutting element holder 12.4. The cutting element 13 consists of a hard material, such as hard metal, and is soldered into the cutting element holder 2.4. FIG. 1 shows the component extensions of the shank bit 10 in the direction of the central longitudinal axis M of the shank chisel 10. In detail, the chisel head 12 including the cutting element 13 has a head length A which is in the range between 35 mm and 60 mm. The first cylindrical portion 11.1 has an extension B in the direction of the Mitteilängsachse M of Meißeischafts <30 mm. In the present case an extension of 15 mm is selected. The length of the transition section is C marked, and should be <10 mm. In the present case an extension of about 3 mm is selected. The length of the second cylindrical portion 11.3 is plotted with D, and has an extension in the direction of the central longitudinal axis M in the range between 10 and 40 mm. The length of the end section E, comprising the securing seat 11.4 and the collar 1 .5, should be at least 3 mm. In the present case, a dimension of 7 mm is selected, wherein the groove width F of the fuse holder 1.4 is approximately 3 mm. in Figure 1, the outer diameter a of the support surface 12.5, the diameter b of the first cylindrical portion 11.1 and the diameter c of the second cylindrical portion 11.3 is further measured. In this case, the diameter b of the first cylindrical sections 11.1 is in the range between 18 mm and 30 mm. The diameter c of the second cylindrical portion 11.3 is selected in the range between 14 mm and 25 mm. The outer diameter a of the support surface 12.5 is presently between 30 mm and 46 mm, and is particularly preferably selected in the range between 40 mm and 44 mm.

FIG. 2 shows a bit holder 40 which is used to receive the shank bit 10 according to FIG. The bit holder 40 has a base part, to which a projection 41 and a plug-in projection 42 are integrally formed. As Figure 3 shows, the projection 41 is provided with a cylindrical inner receptacle 44, in which an insert 20, consisting of hard material, in particular of hard metal, is used. The insert 20 is in the form of a bush, and has a cylindrical outer geometry, which is adapted to the inner diameter d 'of the inner receptacle 44 that results in the assembly of the insert 20 into the Meäßelhalter 40 an interference fit (interference fit). The insertion movement of the insert 20 into the inner receptacle 44 is limited by means of a paragraph. The shoulder is in the transition region of the inner receptacle 44 to a drilled hole formed as a bore. Opening 43 formed. The inner receptacle 44 and the Austreiböffnung 43 are coaxial with each other. The insert 20 has a stepped bore, which has a first diameter portion 21 and a second diameter portion 23. The two diameter regions 21, 23 are merged via a taper 22 into each other. The taper 22 has a frustoconical geometry. As can be seen Fig. 3, the inner diameter c 'of the second diameter portion is smaller than the inner diameter of the expulsion 43. This results in a Austreibschulter the insert 20. Mitteis a introduced through the Austreiböffnung 43 and attached to the Austreibschulter tool can use 20 thus, if necessary, be ejected from the chisel 40.

In Figure 11, the design of the insert 20 is more detailed. As this drawing shows, the outer geometry of the insert 20 is formed by a mating surface 24, which, as described above, forms a snug fit with the inner receptacle 44. Transverse to the central longitudinal axis of the insert 20, the insert 20 has a lower Stoß- flat 25 which abuts in the mounted state on a mating surface of the inner receptacle 44, as shown in FIG. As a result, an exact assignment of the insert 20 to the chisel 40 is made possible. The insert 20, facing away from the abutment surface 25, terminates flush with an abutment surface 26 against an adjacent end face of the chisel holder 40, as FIG. 3 also illustrates. The first diameter portion 21 of the insert 20 has a diameter b ', and the second diameter portion 23 has a diameter c'. The diameters b 'and c' are adapted to the diameters b and c of the first and second cylindrical sections 11.1 and 11.3 of the shank shaft 22, respectively. In this case, the assignment of the shank bit 10 to the insert 20 is ensured with a slight play such that the shank bit 10 remains freely rotatable about its central longitudinal axis M. The extent of the first diameter region 21 in the direction of the As can be clearly seen in FIG. 3, this axis B 'is larger than the extent b of the first cylindrical section 11.1.

The extent of the second diameter region 23 is marked with D 'in FIG. 11 and the extent of the tapering region is marked with C. In this case, the extension D 'is selected so that the drill collar 11 is completely received within the insert 20, as Figure 3 reveals.

As mentioned above, in the area of the chisel shank 11, a sickle recess 11. 4 is provided in the form of a circumferential groove. In this groove, a securing element 30 is added, which is detailed in detail in Figures 4 to 6. As these drawings show, the securing element 30 has a part-ring-shaped circumferential clamping part 32, to which radially adjoin the mounting portions 33, which are present in the form of a chamfer 15 as cross-sectional formed. The cross-sectional reductions are interrupted by recesses 34, wherein the recesses 34 extend into the clamping part 32. In this way, claw-shaped, mutually at an angle α of preferably 50 ° to 70 °, in this case 60 ° spaced, radially outer holding portions 39 are formed in the form of arcuate areas. These convex arc regions 20 serve to tension the securing element 30 in the second diameter region 23 of the insert 20, as FIG. 3 shows. The clamping part 32 surrounds a bearing receptacle 31, which forms a pivot bearing together with the groove bottom of the fuse holder 11.4. This bearing seat 31 opens into a slot which forms an insertion opening 36. In this case, the insertion opening 36 is bordered by two edges 35, which open into insertion chamfers 37. The Einführfasen 37 are arranged so that sow the insertion opening 36 expand. As can be seen from FIG. 5, the bearing receptacle 31 has an inner diameter 38.1, and the fastening portions 33 define an outer diameter 38.2. The securing element 30 has an overall height 38.4, which is smaller than the width of the groove-shaped securing receptacle 11.4. The mounting portions 33 extend over a section height 38.5 and define a slope angle ß.

FIGS. 7 to 10 show a further embodiment variant of a securing element 30. In these figures, like reference numerals refer to corresponding elements already described with reference to FIGS. 4 to 6, and reference may be made to the above embodiments to avoid repetition. The securing element 30 again has a bearing receptacle 31, which is radially accessible via an insertion opening 36. The insertion opening 36 is bounded by a rim 35, wherein the edge 35 merges into insertion chamfers 37. In contrast to the embodiment of Figures 4 to 6, the securing element 30 is made in the form of a stamped and bent part, in which no machining or the like forming work is required for the formation of the angled relative to the clamping part 32 mounting portion 33. Accordingly, a disc-shaped cross-section is first punched out for the production of the securing element 30, and this then deformed in a bending step in the design shown in Figure 8.

As can be seen from FIG. 8, the outer diameter 38. 2 of the securing element 30 is arranged concentrically with the wall (inner diameter 38. 1) forming the bearing receptacle 31. In order to achieve this concentration, the outer contour of the securing element 30 can either be reworked or the diecut is already designed in such a way that after the final bending step, the concentricity is reached. FIG. 8 further shows that the thickness d of the securing element 30 is approximately the same both in the region of the tensioning part 32 and in the region of the fastening section 33. The mounting portion 33 forms on its underside a convex curvature with the radius R, so that there is a relative to the Mitteilängs- axis of the fuse element 30 inclined surface which facilitates mounting of the fuse element 30 in the insert 20 of the bit holder 40, as will be described in more detail below is explained. In the area of its upper side, the securing element 30 is concavely arched. In this way, linear or narrow band-shaped support areas 38.7, which serve for better rotational behavior of the securing element 30 relative to the Schaftmeißei 10, as will be explained in more detail below. The recesses 34 are again part-circularly worked into the fastening section 33 and thereby extend into the region of the clamping part 32.

For mounting the securing element 30 on the shank bit 10, this is first placed with the Einführfasen 37 on the groove bottom of the fuse holder 11.4. Subsequently, by a radial pressure of the drill collar 11 are pushed into the bearing receptacle 31, in which case the pivot bearing between the groove bottom of the fuse holder 11.4 and the bearing seat 31 is formed When inserting the cutter shank 11, the fuse element 30 widens radially, and after the drill collar 11th has passed through the edges 35, the fuse element 30 snaps back into its original shape, so that the chisel shank 11 engages in the bearing receptacle 31. In this way, a captive connection of the securing element 30 is achieved with the shank bit 10. The unit consisting of shank bit 10 and securing element 30 can now be inserted into the insert 20 of the chisel holder 40. To do this attached to the free end of Meißeischafts 11 attachment portions 33 attached to the taper 22. Due to the inclined design of the fastening portions 33, the securing element 30 is compressed radially inward during insertion of the shank bit 10, and can thus be inserted into the second diameter region 23. In this case, the securing element 30 is braced against the inner wall of the second diameter region 23. The deformation of the securing element 30 is such that the free rotation of the shank shaft 11 is maintained. The securing element 30 is reliably supported in the second diameter region 23 with its holding sections 39 in the region of the fastening sections 33. The insertion movement of the shank bit 10 into the insert 20 is limited to the support surface 12.5 of the chisel head 12. This strikes against the support surface 26 of the insert 20, as shown in FIG

During operation use, the shank bit 10 rotates in the bearing receptacle 31. In this case, the chisel head 12 with its support surface 12.5 grinds on the support surface 26 of the insert 20. Since the insert 20 consists of a hard material, and the chisel head 12 of a relatively To softer material is made, the chisel holder 40 is only minor wear. In contrast, the shank bit 10 is worn relatively stronger in the region of its support surface 12.5. This results in a wear system in which the expensive bit holder 40 is worn less than the shank bit 10. Thus, a plurality of shank bits 10 can be driven on a bit holder 40 until it reaches its wear limit. If the shank bit 10 abrades in the region of its support surface 12.5, as indicated above, two Verschieißeffekte on. On the one hand, the structural height of the support section 12.1 is reduced. On the other hand, the support surface 26 of the insert 20 is processed. By these effects, the drill collar 11 sits in the direction of its central longitudinal axis M continuously into the insert 20 into it. Accordingly, the first cylindrical portion 11.1 slides along the first and the securing element 30 along the second diameter portion 21 and 23. Here, the free rotation of the Schaftmeißels 10 is guaranteed about its central longitudinal axis M through the use of a Nachsetzraums NR. In Fig. 3 this Nachsetzraum NR is shown. It is created by the fact that the axial length of the first cylindrical portion 11.1 is smaller than the axial longitudinal extent of the first diameter portion 21. In order to exploit the bit holder 40 with the insert 20 over its maximum possible life verschieißoptimiert, the axial extension of the Nachsetzraums NR be selected in the range between 4 mm to 20 mm.

Given the given geometric conditions, it is possible to approach the lower limit of 4 mm in a rather soft substrate. For hard floor coverings, longer lengths are more suitable for the Nachsetzraum NR. In road construction, mixed concrete and asphalt must be processed, a length of Nachsetzraums 7 mm to 20 mm has been found to be suitable. In order to guarantee the secure fixing of the shank bit 0 over the entire life of the bit holder 40 in the above-described wear system, the second diameter portion 23 of the insert 20 in its axial extent is dimensioned so that the securing element 30 to compensate for the length wear of the insert 20 and the Chisel head 12 on the inner wall of the second diameter portion 23 can slide in the axial direction. Accordingly, therefore, the axial length of the second diameter region must be adapted to the dimensioning of the Nachsetzraums NR. Applied to the above dimensioning specifications, therefore, the second diameter region 23 must at least an axial length of 4 mm to 20 mm plus twice a fixing length for the securing element (position of the securing element 30 in the unworn and worn state of the bit holder 40) have. The fixation length should be at least 2 mm.

As can be seen in FIG. 3, in favor of a compact design, the end-side collar 11. 5 can be recessed into the region of an opening section of the expulsion opening 43. The axial length of the opening portion is to be dimensioned accordingly.

The drill collar 11 slides during operation with its first cylindrical portion 11.1 on the associated inner surface of the first diameter portion 21. Since the insert 20 also consist of a hard material and the drill collar 11 made of a softer material, there is only a small wear of Insert 20 and thus the chisel holder 40 causes.

The securing element 30 according to FIGS. 7 to 10 is supported with its bearing areas 38. 6 and 38. 7 in an annular or annular manner with a small radial extent relative to the groove walls of the securing receptacle 11. 4, as a result of which good rotational behavior is achieved.

After the shank bit 10 is worn, it can be disassembled. For this purpose, an expelling force is introduced into the free end of the drill collar 11 in the region of the collar 11.5 by means of a suitable expelling tool. In this case, the shank bit 10 slides with its securing element 30 over the second diameter region 23 until it rebounds radially in the region of the first diameter region 21. Then the shank bit 10 can be removed freely. FIGS. 12 to 14 show an alternative embodiment variant of the invention. The design of the shank bit 10 corresponds in its basic structure the Schaftmeiße! 10 of FIG. 1. The shank bit 10 gem. Fig. 12 can gem with the retaining ring 30. FIGS. 13 and 14 in the insert 20 of the chisel holder 40 gem. Fig. 2, 3 and 11 are mounted. It will be discussed below to avoid repetition on the distinctive design features. Incidentally, reference is made to the above statements.

The shank bit 10 with chisel shank 11 and chisel head 12 is again made as a press or alternatively as a turned part.

The chisel head 12 has the support section 12.1 with the support surface 12.5. In this case, the support section 12.1 passes over a convex rounding transition into the support surface 12.5. The support section 12.1 has an outer diameter e in the range between 40 mm and 45 mm. The diameter a of the support surface 12.5 is selected in the range between 36 mm and 42 mm. In this diameter ratios, ie more generally at a diameter jump from 1 to 1, 3 (diameter e / diameter a) a strong deformation in the region of the support portion 12.1 is achieved during cold extrusion. These material deformations result in a particularly tough composite material with good strength properties.

The chisel head 12 again has, subsequent to the support section 12.1, a concave taper 12.2, which merges into the truncated conical discharge surface 12.3. At the end, a cutting element holder 12.4 is formed. In this a cutting element (- 13 - see above) can be soldered.

The support surface 12.5 merges via a frustoconical transition section into the first cylindrical section 11.1. The extension of the first cylindrical see section 11.1 in the direction of the central longitudinal axis M is chosen significantly shorter than in the embodiment of FIG. 1. The length B is presently 9 mm. This represents a sufficient dimensioning for a diameter b of 19.8 mm for street milling applications. With the shortened length of the first cylindrical section 11.1, the axial length of the Nachsetzraums NR is increased. In the present case, a particularly suitable wear length for the Nachsetzraum NR of about 15 mm to 18 mm results for road milling applications with mixed coatings (asphalt / concrete). The second cylindrical portion 11.3 has an extension D in the direction of the central longitudinal axis M of 21, 6 mm and thus holds the fuse holder 1 .4 for road milling applications at a sufficient distance from the support surface 12.5. The diameter c of the second cylindrical portion 11.3 is 16.5 mm. The fuse holder 11.4 is designed with a width F of 4.5 mm, thus slightly wider than in FIG. 1 and matched to the fuse element 30 as shown in FIG. 13 and 14.

The end collar 1.5 has a thickness of 3 mm and is thus sufficiently stable for road milling applications.

The design of the securing element 30 will be discussed in greater detail below with reference to FIGS. 13 and 14. The securing element 30 has, as the base body, the stamped and bent part shown in FIGS. 7 to 10, with the difference that the recesses 34 are not recessed into the clamping part 32. With regard to the otherwise matching features, reference is made to the above statements. This base body is provided on its surface with a layer 50 which has a lower hardness than the main body. In the present case, the layer 50 consists of a plastic material. In a particularly preferred application, the layer 50 consists of a plastic material of polyurethane or a composite material containing polyurethane. For reasons of manufacturing simplicity and to create an intimate connection to the main body, the layer 50 is molded onto the base body by injection molding. The layer 50 has two coating areas 51 and 54. The coating areas 51, 54 are arranged on the concavely curved upper side or the convex undersides of the base body. In the region of the recesses 34, the coating regions 51, 54 are connected to each other via connecting portion 55 such that the recesses 34 are completely filled. Thus, the radially outer arc regions of the layer 50 are flush over into the convex arc regions of the holding sections 39. The layer 50 may also project radially beyond the holding portions 39.

With the layer regions filling the recesses 34, application sections 56 are formed radially on the outside. These lie on the inside on the second diameter portion 23 of the insert 20. This results in a Reibflächenpaarung here, which introduces an additional frictional resistance in the direction of the central longitudinal axis, which counteracts a pull-out movement in this direction. In this way, the hold of the shank bit 10 in the insert 20 is improved.

As can be seen from FIG. 13, the radially outer regions of the holding sections 39 remain free, so that their function as described above is retained. In addition, the Einführfasen 37 and the edges 35 remain uncoated, so that the Guide function during assembly in the cutting element holder 12.4 is maintained. Furthermore, the inner diameter 38.1 is free and forms with the groove bottom of the fuse holder 11.4 a wear-resistant and permanently accurate pivot mounting.

The two coating regions 51 and 54 each form a bearing surface 52, 53 which rotate in the form of a partial ring around the central longitudinal axis of the securing element 30. The two bearing surfaces 52, 53 are radial and parallel to each other. They serve to rest on the groove walls of the securing receptacle 11.4, whereby the axial clearance described above must be maintained. To achieve a tilt-free run, the axial clearance should be selected in the range between 0.2 mm and <4 mm. The two bearing surfaces 52, 53 complete the tailor-made rotary bearing. The layer 50 increases the rigidity, in particular the torsional strength of the base body, so that this rigid composite body fixes the shank bit 0 reliably.

Claims

claims

A tool system comprising a bit holder (40) and a shank bit (10), the bit holder (40) having a bit receptacle having first and second diameter portions (21, 23) extending over a transition section (taper (22)) a chisel shaft (11) of the shank bit (10) has a first and a second cross-sectional area (first and second cylindrical sections (21 and 23)), which are merged into one another via a transition section (1 .2),

characterized,

in that the transition sections (narrowing (22) and (1.2)) of the shank bit (10) and the bit holder (40) are arranged spaced apart from one another in the direction of the central longitudinal axis (M) of the shank bit (10) to form a resetting space (NR).

2. Tool system according to claim 1,

characterized,

in that the bit holder (40) has a bearing surface (26) on which the shank bit (10) is indirectly or directly supported by a support surface (12.5) of its bit head (12).

3. Tool system according to claim 1 or 2,

characterized,

the first and the second cross-sectional area of the drill collar (11) are provided by a first and a second cylindrical area (11.1 and 1 .3). Det, wherein the first cylindrical portion (11.1) has a diameter (b) in the range between 18 mm and 30 mm and an extension (B) in the direction of the central longitudinal axis (M) of the Schaftmeißels (10) less than or equal to 30 mm.

4. Tool system according to one of claims 1 to 3,

characterized,

in that the transition sections (narrowing (22) and (11.2)) of the bit holder (40) and the shaft bit (10) are arranged spaced apart in the range between 4 mm and a maximum of 30 mm.

5. Tool system according to one of claims 1 to 4,

characterized,

in that the tool holder is formed by an insert (20), consisting of hard material, which is arranged in an inner receptacle (44) of the tool holder (40).

6. Tool system according to one of claims 1 to 5,

characterized,

that with the first cross-sectional area (first cylindrical portion (11.1)) of the drill collar (11) and the first diameter portion (21) of the bit receptacle and / or with the second cross-sectional area (second cylindrical portion (11.3)) of the drill collar (11) and the second Diameter range (23) is formed a rotary bearing and / or a sliding guide with direction of action in the direction of the central longitudinal axis (M) of the Schaftmeißels (10)

7. Tool system according to one of claims 1 to 6, characterized,

the shank bit (10) has a securing element (30) which is adjustable in the direction of the longitudinal axis (M) of the shank bit (10) along a sliding guide of the bit holder.

8. Tool system according to claim 7,

characterized,

in that the sliding guide is formed by the first or the second diameter region (21, 23)

9. Tool system according to one of claims 1 to 8,

characterized,

in that the securing element (30) has a spring-elastic clamping part (32) which surrounds a bearing receptacle (31) at least in regions, and in that fastening parts (33) are connected to the clamping part (32) directly or indirectly radially on the outside, which are spaced apart from one another in the circumferential direction are.

10. Tool system according to one of claims 9,

characterized,

that the drill collar (11) terminates at its free end with a collar (11.5) or the like end portion, and

in that the bit holder (40) has an opening section following the bit receptacle into which the collar (11.5) or the like end section can be inserted.

11. Tool system according to claim 10,

characterized, in that the opening section is formed by a material area of the chisel holder (40) adjoining the insert (20).

12. Tool system according to claim 10 or 1,

characterized,

the opening portion has an expulsion opening accessible from the bit holder rear side.

13. Tool system according to one of claims 1 to 12,

characterized,

the bit holder (40) has an insertion projection (42) for interchangeable mounting in a base part.