EP2540451A2 - Chisel tool - Google Patents

Abstract

The tool has a chisel head (1) comprising a chisel bit (5) at a free axial end of the chisel head and forming a bracket bit (7) to the chisel bit in an axially-displaced manner. The bracket bit is released by removal of tool material, and replaces a part of the chisel bit, where the removal of materials is decreased to tool wear. A reinforcing structure (8) runs adjacent to a transition region between the chisel bit and the bracket bit for reinforcing the chisel head. The reinforcing structure comprises two reinforcing parts (9a, 9b), which run axially and form additional bracket bits.

Description

The invention relates to a chisel tool according to the preamble of claim 1.

Chisel tools of the type in question are equipped with a chisel head, a chisel shank and an insertion end, which are arranged one behind the other along a longitudinal axis of the chisel. The chisel head has at its free axial end a chisel cutting edge, which is responsible for the material removal. Such chisel tools are primarily used as a rock chisel.

Usually, the insertion end of the chisel tool is adapted to be inserted into the chuck of a hammer drill, a chisel hammer or the like. For this the insertion end is then equipped with an SDS-Plus interface, an SDS-Max interface or the like.

The well-known chisel tool ( DE 100 57 124 A1 ), from which the invention proceeds, has the above basic structure. The known chisel tool can be formed as a pointed chisel with a tapered cutting edge or as a flat or Spatmeißelwerkzeug with a correspondingly flat chisel cutting edge.

Each bit tool is subject to some tool wear due to the bit engagement between the bit edge and the material to be chiseled. The tool wear manifests itself in a plastic deformation of the chisel cutting edge, but above all in a removal of tool material in the area of the chisel cutting edge. With the chisel operation is correspondingly accompanied by a continuous shortening of the chisel tool.

In order to ensure that good removal rates are achieved despite the above tool wear, a regular regrinding can not be dispensed with in the known tool. This is associated with a considerable time and personnel, which ultimately leads to significant, attributable to the chisel tool operating costs.

The invention is based on the problem of designing and further developing the known bit tool in such a way that the operating costs attributable to the bit tool are reduced.

The above problem is solved in a chisel tool according to the preamble of claim 1 by the features of the characterizing part of claim 1.

The proposed solution is based on the fundamental idea of equipping the chisel head with at least one replacement cutting edge, which at least partially replaces the function of the chisel cutting edge after a certain tool wear.

Specifically, the bit head axially offset from the bit cutting edge forms at least one replacement blade which is exposed by the removal of tool material due to tool wear and then replaces at least a portion of the bit edge. The term "axial" is in this case always based on the longitudinal axis of the bit.

By "exposing" the replacement blade is meant in general that the replacement blade in the exposed state forms at least part of the contact surface of the bit tool to be chiseled material.

With the proposed solution, it can be achieved that the replacement of the original chisel cutting edge by the at least one replacement cutting edge automatically accompanies the tool wear, so that the replacement cutting edge then provides at least part of the cutting edge, preferably the entire cutting edge.

The tool wear exposing the replacement cutting edge can basically only be attributed to an abrasion process on the bit stacker. Preferably, however, the tool wear exposing the replacement blade is partly due to an abrasion process and partly to a fracturing operation on the bit head (claim 2). By a suitable design of the mechanical structure of the chisel head, the exposure of the replacement blades can then be set very precisely.

In the simplest case, close to the original chisel cutting a number of replacement blades, the original chisel cutting edge and the replacement blades along the chisel longitudinal axis are arranged one behind the other. Preferably, the original chisel cutting edge and the replacement cutting edges are arranged directly behind one another along the longitudinal axis of the cutting bit. In this case, each replacement cutting edge forms a taper in a cross section parallel to the longitudinal axis of the bit, which forms at least a portion of the bit edge after the corresponding replacement cutting edge has been exposed.

However, the above tapers also lead to a mechanical weakening of the chisel tool, so that in the particularly preferred embodiment according to claim 3, a reinforcing structure for reinforcing the chisel tool, here and preferably a transition region between the respective cutting is provided.

In the further preferred embodiments according to claim 10, the chisel tool in question is a flat chisel or a latex chisel. This variant is easy to produce and at the same time ensures a particularly high mechanical stability.

In the likewise preferred embodiment according to claim 13, it is provided that the chisel tool is designed as a pointed chisel. In a further preferred embodiment according to claim 13, the reinforcing members enclose the here and preferably pyramidal replacement blades on the side edges of the respective pyramidal shape. With this structure surprisingly good results in terms of mechanical stability can be achieved with a particularly low use of tool material.

Fig. 1

eine erste Ausführungsform eines vorschlagsgemäßen Meißelwerkzeugs in einer perspektivischen Ansicht,

Fig. 2

das Meißelwerkzeug gemäß Fig. 1 in einer Seitenansicht und in diversen Schnittansichten,

Fig. 3

eine weitere Ausführungsform eines vorschlagsgemäßen Meißelwerkzeugs in einer perspektivischen Ansicht,

Fig. 4

das Meißelwerkzeug gemäß Fig. 3 in einer Seitenansicht und in diversen Schnittansichten,

Fig. 5

verschiedene Varianten für die Auslegung von Ersatzschneiden, die auf die Meißelwerkzeuge gemäß Fig. 1 bis 4 Anwendung finden können,

Fig. 6

eine weitere Ausführungsform eines vorschlagsgemäßen Meißelwerkzeugs in einer perspektivischen Ansicht,

Fig. 7

das Meißelwerkzeug gemäß Fig. 6 in einer Seitenansicht und in diversen Schnittansichten,

Fig. 8

eine weitere Ausführungsform eines vorschlagsgemäßen Gesteinswerkzeugs in einer perspektivischen Ansicht und

Fig. 9

das Gesteinswerkzeug gemäß Fig. 8 in einer Seitenansicht und in diversen Schnittansichten.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. In the drawing shows

Fig. 1

a first embodiment of a proposed chisel tool in a perspective view,

Fig. 2

according to the chisel tool Fig. 1 in a side view and in various sectional views,

Fig. 3

a further embodiment of a proposed chisel tool in a perspective view,

Fig. 4

according to the chisel tool Fig. 3 in a side view and in various sectional views,

Fig. 5

different variants for the design of replacement blades, according to the chisel tools according to Fig. 1 to 4 Application can find

Fig. 6

a further embodiment of a proposed chisel tool in a perspective view,

Fig. 7

according to the chisel tool Fig. 6 in a side view and in various sectional views,

Fig. 8

a further embodiment of a proposed rock mold in a perspective view and

Fig. 9

according to the rock tool Fig. 8 in a side view and in various sectional views.

It may be said in advance that the proposed solution is applicable to all conceivable types of chisel tools. The drawings show preferred variants for a latex chisel ( Fig. 1 to 5 ) on the one hand and preferred variants for a pointed chisel ( Fig. 6 to 9 ) on the other hand. However, this is not restrictive.

The illustrated chisel tools have a chisel head 1, a chisel shank 2 and an insertion end 3, which are arranged one behind the other along a chisel longitudinal axis 4. The chisel head 1 is equipped at its free axial end with a chisel cutting edge 5, which determines the chisel engagement with the material to be chiseled.

The above-mentioned tool wear leads inter alia to a removal of tool material, usually the tool steel, so that the position of the chisel blade 5 steadily "moves" against the chisel 6, the chisel tool is thus shortened.

According to the proposal, the above "wandering" of the chisel cutting edge 5 is utilized in order to effect an automatic and continuous replacement of a blunt cutting edge 5 against a replacement cutting edge 7 to be explained later. For this purpose, the chisel head 1 axially offset from the chisel cutting edge 5 at least one replacement cutting edge 7, in Fig. 2 a total of six replacement blades 7a-f, from, wherein the replacement blades 7 are not exposed when still unused chisel tool, ie in the original state, and are located within the chisel head 1. The replacement blades 7 are designed here, and preferably in a substantially parallel to the longitudinal axis of the chisel 4 cross-section substantially wedge-shaped.

Only through the deduction of tool material attributable to tool wear, the replacement blades 7 are exposed one after the other, wherein in each case the replacement blade 7 just exposed replaces the original cutter blade 5 in part. The shape of the original chisel cutting edge 5 is the view A in the Fig. 2 and 4 refer to.

It can be the representations in the Fig. 1 to 5 can be seen that the replacement blades 7 replace the original chisel cutting 5 only partially here, namely in a central region of the chisel tool.

In detail, the bit operation by the action of the bit tool in chisel 6 causes first the wear-related removal of tool material in the area of the original chisel cutting edge 5, which in the illustrations according to Fig. 2 . 4 . 7 and 9 each clearly visible.

The above tool wear first causes the contact surface of the chisel cutting edge 5 to increase, the chisel cutting edge 5 becomes duller.

As the tool wear progresses, the removal of tool material continues until the replacement blade 7a is exposed. The contact area between Chisel tool and the material to be chiseled is thus reduced, the chisel tool is sharpened accordingly.

In the further chiseling operation, the replacement cutting edge 7a itself acts as a chisel cutting edge 5, which wears as above until the second replacement cutting edge 7b is uncovered. This in turn is accompanied by a corresponding sharpening of the chisel tool.

The above operation of the proposed chisel tool continues successively for all replacement blades 7 accordingly.

The tool wear that causes the release of the respective replacement cutting edge 7 can basically only be attributed to an abrasion process on the bit head 1, which ensures a high level of continuity during the exposure. In a particularly preferred embodiment, however, it is provided that the exposure of the replacement blade 7 causing tool wear only partially due to an abrasion process and partly also on a fracture process on the chisel head 1. As indicated above, the exposure can then be precisely controlled by a corresponding structural design.

In order to enhance the above self-sharpening effect, it is desirable to make each of the replacement blades 7 as sharp as possible. This means that the connection point of the replacement cutting edges 7 to the respective upstream cutting edge 5, 7 is mechanically correspondingly weak. The weakening of the chisel head 1 in the area of the replacement blades 7 can best be seen in the sectional views BB in FIG Fig. 2 and 4 remove. Against this background, a reinforcing structure 8 for reinforcing the chisel head 1, here and preferably in each case of the axial transition region between two cutting edges 5, 7, is provided. Accordingly, the reinforcing structure 8 preferably extends substantially axially and preferably adjacent to a region between two cutting edges 5, 7. Here, and preferably, the reinforcing structure 8 extends essentially over the entire bit head 1 along the longitudinal axis 4 of the bit.

In the illustrated and insofar preferred exemplary embodiments, the reinforcing structure 8 has at least two axially extending reinforcing parts 9a-d on which laterally surround the at least one replacement cutting edge 7. It is essential in all the illustrated embodiments that at least a part of the reinforcing parts 9a-d are elongated.

In terms of a particularly compact structure, it is provided in all embodiments that extend at least a portion of the reinforcing members 9 axially to the original chisel cutting edge 5. In order to avoid that the reinforcing members 9 hinder the chisel operation, it is further preferably such that the reinforcing members 9a, 9b at least partially taper towards the original chisel blade 5. This is where in the Fig. 1 and 2 each embodiment has been implemented by a tapering region 10. It is also conceivable that the reinforcing parts 9a-d taper at least in sections to the insertion end 3, as in the still to be explained Fig. 6 and 7 is shown.

In the in the Fig. 3 and 4 illustrated embodiment, several Verjürigungsbereiche 10 are provided. A comparison of the sectional views BB in the Fig. 2 and 4 shows that the obstruction of the chisel progress by the in Fig. 2 shown reinforcing parts 9 at the in Fig. 4 embodiment shown largely eliminated.

It is best to cut the DD in Fig. 2 can be seen that the reinforcing members 9a, 9b here and preferably are designed substantially rod-like, in particular cylindrical. It is also conceivable, however, for the reinforcing parts 9a, 9b to be deviating therefrom, in particular cuboidal. It is also conceivable, however, the realization of rib-shaped reinforcing parts 9e-h, as in the still to be explained Fig. 6 to 9 is shown.

In the embodiment of the chisel tool as spade or flat chisel, it may be provided depending on the application that the reinforcing members 9a, 9b perpendicular to the flat side of the chisel tool have a width which is smaller, equal to or greater than the corresponding width of the intermediate replacement cutting 7.

With a suitable design of the reinforcing structure 8, it is even possible to provide a recess, not shown, in the region between two cutting edges 5, 7, so that the replacement cutting edge 7 can be designed to be particularly sharp in a simple manner. Against the background of one of the respective cutting edge 7 axially upstream recess, the above formulation "exposing the Erdsatzschneide" is interpreted accordingly wide.

Interesting in the in the Fig. 3 and 4 and thus far preferred embodiment is the fact that the reinforcing members 9a, 9b themselves form additional replacement blades 11 af which, like the replacement blades 7a-f explained above, are successively exposed and then replace part of the original bit 5. Particularly advantageous is the fact that the obstruction of the chisel operation by the reinforcing members 9 as mentioned above can be significantly reduced.

A further preferred variant, not shown here, provides that the additional replacement cutting edges 11 are arranged axially offset relative to the replacement cutting edges 7 surrounded by the reinforcing parts 9. On the one hand a good chisel progress and on the other hand a high mechanical stability can be achieved.

In order to prevent a change in the chisel characteristic as far as possible in the course of a self-sharpening above, the shape of the at least one replacement cutting edge 7 at least partially substantially corresponds to the shape of the original chisel cutting edge 5. This has been implemented in all illustrated and insofar preferred embodiments.

The chisel cutting edge 5 and the at least one replacement cutting edge 7 in all the illustrated embodiments run essentially pointed towards the free end of the chisel head 1, here and preferably the chisel cutting edge 5 and the at least one replacement cutting edge 7 facing in a free end of the chisel head 1, axial direction of the chisel edge 5 more sharply than in the remaining axial region of the chisel cutting edge 5. The chisel cutting edge 5 and the at least one replacement cutting edge 7 are sharpened as it were.

It can also be seen from the drawing that in the illustrated embodiments, several replacement blades 7 are provided, which are arranged axially one behind the other, more preferably the chisel head 1 in the area the replacement cutting edge 7 is configured substantially sawtooth-like in a cross-section parallel to the longitudinal axis of the bit 4. This ensures that a blade 5, 7 immediately follows a replacement blade 7, without any "blunt" intermediate sections are interposed. The sawtooth-like configuration can be provided on one side or, as shown, on both sides.

Fig. 4 shows that there are the reinforcing parts 9 in cross-section parallel to the longitudinal axis of the chisel 4 also sawtooth configured, which ultimately goes back to the realization of the additional replacement blades 11. The saw tooth structure is shown on the flat front and back sides of the chisel tool. It is also conceivable that the free side surfaces of the reinforcing members 9 are equipped with a sawtooth structure.

In all the above sawtooth structures, it can be provided in principle that the sawtooth structures are edged or at least partially rounded. Thus, an optimization with regard to possible wedge effects can be made.

In the in the Fig. 1 to 5 illustrated embodiments, the chisel tool is designed as a latex chisel. In this case, it is preferably the case that the original cutting edge 5 extends essentially transversely to the longitudinal axis of the bit 4, here and preferably even in a straight line.

Correspondingly, the replacement blades 7 also run essentially transversely to the longitudinal axis of the bit 4, here and preferably also a substantially rectilinear course of the replacement blades 7 is provided. This corresponds to the above proposal to adapt the shape of the replacement blades 7 to the shape of the original chisel cutting edge 5.

For the shaping of the replacement blades 7 numerous advantageous variants are conceivable. For the design of the chisel tool as a late chisel this is in Fig. 5a-e shown.

Fig. 5a shows, for example, that the replacement blades 7 extend in the chisel direction 6 convex. By the phrase "convex in the chisel direction" is meant that the convex protrusion is provided in the chisel direction 6. However, it can also be provided inversely that the replacement blades 7 run convexly counter to the direction of the bit 6. This is in Fig. 5b shown.

In the further preferred embodiment according to Fig. 5c are the replacement blades 7 set against a transversely to the longitudinal axis of the chisel 4 extending reference axis. The angle of attack φ is here and preferably in a range between 25 ° and 55 °, in particular at about 40 °. The resulting asymmetry can bring a particularly advantageous effect in terms of vibration reduction with it.

It is also conceivable that the replacement blades 7 in the chisel 6 ( Fig. 5d ) or against the chisel direction 6 (FIG. Fig. 5e ) are designed arrow-shaped. Depending on the material to be chiseled, the chisel progress can be optimized.

It may be noted that the in Fig. 5 shown variants for the shaping of the replacement blades 7 can be found in each case only on a part of the respective replacement blades 7 application.

In the in the Fig. 1 to 5 illustrated embodiments are each represented reinforcing structures 8, which have been found in experiments to be particularly advantageous. It is such that the two axially extending reinforcing parts 9a, 9b, the replacement blades 7 each end border. The two reinforcing parts 9a, 9b run here and preferably parallel to one another and parallel to the longitudinal axis of the bit 4.

In principle, the width of the chisel head 1 perpendicular to the flat side of the chisel head 1 along the longitudinal axis of the chisel 1 can be provided substantially constant. However, here and preferably it is the case that the width of the chisel head 1, in particular the replacement cutting edges 7 and / or the reinforcing parts 9, increases counter to the chisel direction 6, which leads to a high mechanical stability in the chisel direction 6.

In the in the Fig. 6 to 9 shown, further preferred embodiments, the proposed chisel tool is designed as a chisel. Here, in a particularly preferred embodiment, the original chisel blade 5 is substantially cone-shaped, designed here and preferably pyramid-shaped. In the illustrated and so far preferred embodiments follows in the Fig. 6 and 7 shown, original chisel cutting 5 a pyramid shape with a substantially square base. Conceivable are pyramid shapes with a largely arbitrary number of corners in the base.

Both in the Fig. 6 . 7 and 8th . 9 In each case, it is not an ideal pyramid shape, but an approximate pyramid shape. In that regard, the term "pyramid shape" is to be understood broadly. For example, the side surfaces of the pyramidal shape may also be substantially concave.

It is interesting that in the sense of the uniform shaping of original chisel cutting edge 5 and replacement cutting edges 7, the replacement cutting edges 7 are also substantially cone-shaped, here and preferably pyramid-shaped. Here too, in a cross section parallel to the longitudinal axis of the bit 4, a substantially sawtooth-like structure is evident, as in the sectional views BB in FIGS Fig. 7 and 9 is shown.

In a fundamentally desirable, ideally tapered embodiment of the replacement blades 7, only a punctiform connection between two cutting edges 5, 7 would exist. Accordingly, also in the in the Fig. 6 to 9 illustrated embodiments, preferably a reinforcing structure 8 is provided. Here, it is the case that the reinforcing parts 9a-d or 9e-h enclose the pyramidal replacement cutting edges 7 on the side edges of the respective pyramidal shape.

In the in the Fig. 6 to 9 illustrated embodiments, rib-like reinforcing parts 9e-h are provided, which laterally surround the substantially conical replacement blades 7, wherein the rib-like reinforcing members 9e-h relative to the longitudinal axis of the chisel 4 are substantially radially aligned and axially between two replacement blades 7, here and preferably also between the first replacement cutting edge 7a and the original cutting edge 5. The rib-like reinforcing parts 9e-h form wall sections, which in any case engage with the replacement blades 7. Characterized in that the reinforcing parts 9e-h are stressed in the chisel operation primarily on pressure, results in a mechanical structure with a high mechanical resistance moment. With a suitable design can be achieved that this originally strong structure is deliberately weakened in the course of chisel operation, if it is violated by the attributable to the tool wear erosion of tool material. This weakening may result in a controlled acceleration of the exposure of the next replacement blade 7.

The targeted weakening mentioned above can be controlled, for example, by a suitable design of the rib-like reinforcing parts 9e-h. It can be the representations according to the Fig. 6 to 9 For example, it can be seen that the height of the ribs 9e-h, in this case the radial extension of the ribs 9e-h, is lowest in the axial regions of the tips of the replacement blades 7. The concomitant weakening of the ribs 9e-h can be used to a certain extent as a predetermined breaking point. Alternatively or additionally, the ribs in each case in the region which is to serve as a predetermined breaking point, be designed to be thinner than in the remaining regions of the ribs.

The reinforcing structure 8 is in the in the Fig. 8 . 9 illustrated embodiment exclusively of rib-like reinforcing parts 9e-h, which simplifies the production of the chisel tool. In the in the Fig. 6 and 7 On the other hand, in the illustrated embodiment, rod-like reinforcing parts 9a-d are additionally provided, which lead to additional stabilization. The rod-like reinforcing parts 9a-d taper in sections towards the insertion end 3, namely along a replacement cutting edge 7, which leads to a step-like nature of the rod-like reinforcing parts 9a-d. By this stage, in turn, predetermined breaking points arise between two replacement blades 7, which has a favorable effect on the controlled exposure of the respective replacement blade 7.

Here and preferably, it is provided that the rib-like reinforcing parts 9e-h at least partly bridge a radial area between a replacement cutting edge and a rod-like reinforcing part 9a-d. This makes it possible to set a high mechanical resistance moment for the chisel operation.

The views A in the Fig. 7 and 9 each show that the original chisel cutting edge 5 in plan view is designed substantially star-shaped and according to Fig. 6 to 9 has four star-shaped extending cutting portions 5a-d. In the sense of the above, formal matching of the replacement blades 7 to the original chisel blade 5, it is further preferably such that the exposed replacement blades 7 are also configured star-shaped in plan view, which is the view DD in the Fig. 7 and 9 each can be removed.

It follows from the above explanations that the controlled exposure of the replacement blades 7 is of particular importance here. This can be done by a suitable structural design and arrangement of the replacement cutting edges 7 on the one hand and the reinforcing structure 8 on the other hand. It can be provided in addition to the already occurring abrasion also targeted fracture operations. This relates in particular to the regularly existing tapering region between two cutting edges 5, 7, the rod-like reinforcing parts 9a-d and the rib-like reinforcing parts 9e-h. Through a targeted introduction of above-mentioned predetermined breaking points, the targeted exposure of the replacement blades 7 can be realized in a particularly simple manner.

The proposed chisel tool is preferably formed in one piece. With a suitable design, it can be produced without cutting or machining, in particular in the forging, casting, rolling, grinding or milling process. In principle, however, is also conceivable that the proposed chisel tool is designed in several parts. It may be advantageous to design the replacement blades 7 as insert elements. Finally, it may be advantageous to design the chisel head, the chisel shank 2 and / or the insertion end 3 as separate parts which are pressed together or the like.

Finally, it should be pointed out that the reinforcing structure 8 is preferably optimized for a high resulting moment of resistance of the chisel head 5 with respect to a torsional and / or bending stress. One possibility for this is to make the reinforcing parts 9 stronger towards the insertion end 3, in particular the rod-like reinforcing parts 9a-d for the insertion end 3 with an increasing cross-section and / or the rib-like reinforcing parts 9e-h with an increasing wall thickness. It is also conceivable in this connection to increase the moment of resistance by means of structural measures, in particular by means of a radial extension of the rib-like reinforcing parts 9e-h which becomes larger towards the insertion end 3.

Claims (15)

Chisel tool with a chisel head (1), chisel shank (2) and insertion end (3), which are arranged one behind the other along a chisel longitudinal axis (4), wherein the chisel head (1) has a chisel cutting edge (5) at its free axial end,
characterized,
in that the bit head (1) forms at least one replacement cutting edge (7) axially offset from the bit cutting edge (5), which is exposed by the removal of tool material due to tool wear and then replaces at least part of the bit cutting edge (5). Chisel tool according to claim 1, characterized in that the tool wear which causes the uncovering of the replacement blade (7) is partly due to an abrasion process and partly to a fracturing operation on the chisel head (1). Chisel tool according to claim 1 or 2, characterized in that a reinforcing structure (8) for reinforcing the chisel head (1), in particular an axial transition region between two cutting edges (5, 7), is provided, preferably that the reinforcing structure (8) substantially axially and preferably adjacent to a transition region between two cutting edges (5, 7). Chisel tool according to claim 3, characterized in that the reinforcing structure (8) has at least two in particular axially extending reinforcing members (9) which laterally surround the at least one replacement blade (7), preferably in that the axially extending reinforcing members (9) at least in sections tapering the chisel cutting edge (5) towards or towards the insertion end (3). Chisel tool according to claim 3 or 4, characterized in that the reinforcing parts (9) are at least partially rod-like, preferably at least partially substantially cylindrical or cuboid-shaped, and / or that the reinforcing parts (9) are configured at least partially rib-like. Chisel tool according to claim 4 or 5, characterized in that the reinforcing members (9) form additional replacement blades (11), preferably in that the additional replacement blades (11) are offset axially from the replacement blades (7) enclosed by the reinforcing members (9). Chisel tool according to one of the preceding claims, characterized in that the shaping of at least one replacement cutting edge (7) at least partially substantially corresponds to the shape of the original chisel cutting edge (5). Chisel tool according to one of the preceding claims, characterized in that the chisel cutting edge (5) and / or the at least one replacement cutting edge (7) tapers substantially towards the free end of the chisel head (1), preferably that the chisel cutting edge (5) and or the at least one replacement cutting edge (7) in a free end of the chisel head (1) facing axial portion of the chisel cutting edge (5) tapers sharper than in the remaining axial region of the chisel cutting edge (5). Chisel tool according to one of the preceding claims, characterized in that a plurality of replacement blades (7) are provided, which are arranged axially one behind the other, preferably that the chisel head (1) in the region of the replacement blades (7) in a cross section parallel to the longitudinal cutting bit axis (4). is configured substantially sawtooth-like. Chisel tool according to one of the preceding claims, characterized in that the chisel tool is designed as a flat chisel or spatula chisel. Chisel tool according to one of the preceding claims, characterized in that the chisel cutting edge (5) and / or the replacement cutting edge (7) extends substantially transversely to the longitudinal axis of the chisel (4). Chisel tool according to one of the preceding claims, characterized in that at least one replacement cutting edge (7) extends convexly at least in the chisel direction (6) or counter to the chisel direction (6), and / or that at least one replacement cutting edge (7) is at least partially opposite one another extends to the longitudinal axis of the chisel (4) extending reference axis, and / or that at least one replacement blade (7) in the chisel direction (6) or against the chisel direction (6) extends arrow-shaped. Chisel tool according to one of the preceding claims, characterized in that the chisel tool is designed as a chisel, preferably, that the chisel cutting edge (5) and / or the at least one replacement cutting edge (7) is substantially conical, in particular pyramid-shaped, more preferably, that the reinforcing parts (9) enclose the pyramidal replacement blades (7) on the side edges of the pyramidal shape. Chisel tool according to claims 4 and 13, characterized in that rib-like reinforcing parts (9e-h) are provided, which laterally enclose the substantially conical replacement blades (7), preferably in that the rib-like reinforcing parts (9e-h) are movable relative to the longitudinal axis of the bit (9e-h). 4) are substantially radially aligned and extend axially between two replacement blades (7). Chisel tool according to claim 14, characterized in that the rib-like reinforcing parts (9e-h) at least partly bridge a radial area between a replacement cutting edge and a rod-like reinforcing part (9a-d).

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