5 10 15 Tool Holder, and Chisel Support and Drilling Bit for a Drill Head The invention relates to a tool holder for a drill head with a fastening shank through which a mud channel passes and with a support structure fastened directly or indirectly to the fastening shank. 20 The invention also relates to a drill bit support for a drill head, with a support head on which a bearing section of a drill bit can be fastened in rotary fashion. And finally, the invention also relates to a drill bit for rotary attachment to a drill bit 25 support. Drill heads are used to dig drilling holes in the ground for construction projects. To do so, the drill heads are fastened at one end to a drill pipe. The rotation and the advancing motion of a drive unit are transferred to the drill head by means of 30 the drill pipe.
2 For example, horizontal drilling machines are known from the prior art, which are used to produce a rather horizontal bore in the ground. This is done to drive the drill head under roads, buildings, or the like. Usually, the drill heads have a tool holder that holds drill bits, which are supported in sockets in rotary fashion. When 5 the drill head is driven through the ground, the drill bits roll against the material to be removed and break it free. This causes it to fragment so that it can be flushed away with a mud emulsion. The mud emulsion is supplied to the drill heads via the drill pipe. The drill heads are subject to wear and must therefore be regularly replaced. 10 The object of the invention is to create a drill bit support and a drill bit, which are designed so that they are optimized with regard to wear. The object of the invention relating to the tool holder is attained in that the 15 support structure has tool sockets offset from one another in the circumference direction for accommodating drill bit supports in a replaceable fashion. According to the invention, therefore, a wear system is created in which the tool holder has an interface for the replaceable coupling of the drill bit support. 20 Consequently, the tool holders and the drill bit supports can be replaced independently of one another in accordance with their wear state. This achieves an optimization of the service life of the individual tool components. According to a preferred embodiment of the invention, it is possible for the tool 25 sockets to be embodied in the form of insertion sockets. Consequently, the drill 3 bit supports can be easily changed and precisely positioned, even in the rough conditions of worksite operations and in installation situations with limited accessibility. 5 In this connection, it is particularly advantageous if the tool sockets have an insertion opening, which opens in the direction oriented away from the fastening shank or in a radially outward direction. Consequently, the drill bit supports can be inserted into the insertion sockets from the front side or rear side of the drill head. Alternatively, the insertion socket can also be embodied in the form of a 10 guide projection onto which the drill bit support can be slid. A tool holder according to the invention can be embodied so that in the region of the tool socket, a fastening receptacle, in particular a screw receptacle, is provided, which opens in the direction toward the fastening shank and is 15 accessible from there. Consequently, the screw receptacle is oriented so that the screw head of a fastening screw that has been inserted into the screw receptacle is favorably positioned with regard to wear. In particular, it is then not exposed to the abrasive wear action. 20 A possibility for exact positioning of the drill bit supports is provided in a simple way if the tool sockets have two guide grooves or guides situated on opposite sides from each other. In this connection, a favorable centering is achieved if the guide grooves are 25 laterally delimited by two flanks, which extend in the longitudinal direction of the groove and are oriented at an angle relative to each other. This design is also load-optimized. The wall sections of the tool sockets that form the grooves become thicker in the direction toward the bottom of the groove and thus have a 4 large load cross-section at the location in which the highest loads occur. It is particularly preferable if the tool sockets are each at least partially composed of two guide projections and outlet channels are formed between the guide 5 projections of adjacent tool sockets. The rock material that is removed with the supplied emulsion can be conveyed away via the outlet channels. The object of the invention relating to the drill bit support is attained in that an insertion lug is directly or indirectly coupled to the support head of the drill bit 10 support. By means of this insertion lug, the drill bit support can be inserted into a correspondingly embodied tool socket of the tool holder. It can then be replaced independently of the tool holder, each as a function of its individual wear state. On the one hand, this achieves a wear-optimized design. On the other hand, by means of its insertion lug, the drill bit support can be quickly and simply attached 15 to the tool holder and detached from it again. It is particularly preferable for the insertion lug to have guide pieces on two opposing sides. By means of these guide pieces, it can be inserted, for example, into grooves of the tool holder, in order to thus achieve a reliable and exact 20 positioning. For a load-optimized design, the guide pieces can have two guide surfaces that are oriented at an angle relative to each other and are connected to each other via a connecting section. The guide pieces widen out starting from their free 25 5 ends. They therefore have their maximum cross-section in the region in which they connect to the drill bit support and therefore have a load-optimized design. A particularly preferred variant of the invention is one in which the insertion lug 5 has a support lug at its free end. This support lug produces an additional stable attachment. For example, it is also possible for the support lug to transition into the guide pieces in a way that results in an easy-to-produce geometry. 10 A drill bit support according to the invention can also be embodied so that the insertion lug is delimited by a convex inner surface and/or a convex outer surface. In the region of the convex inner surface, the drill bit support can correlate with a correspondingly concave recess of the tool holder. The matching 15 convex/concave regions in the vicinity of the inner surface produce an interface, which, like the principle of a key in a lock, promotes the association of the correct drill bit support with a tool holder. The convex outer surface of the drill bit support reduces the number of possible weak points of the bore wall and thus contributes to a wear-optimized layout of the tool design. The convex shape also achieves a 20 thickening of the insertion lug cross-section and thus a greater stability. A drill bit support according to the invention can be characterized in that the support head supports a bearing section and in that labyrinth seal parts are situated in the transition region from the support head to the bearing section. 25 These labyrinth seal parts can be put together with corresponding labyrinth seal parts of a drill bit in order to thus produce a labyrinth seal. This labyrinth seal 6 counteracts the penetration of rock material and thus protects the bearing section and a bearing contained therein. A drill bit can be affixed to a drill bit support in a simple way in that the bearing 5 section is provided with a circumferential groove for accommodating a clamping element. The clamping element can then be connected to the drill head with form-locking engagement and/or frictional, nonpositive engagement. In a particularly preferred embodiment according to the invention, the central 10 longitudinal axis formed by the bearing section extends at an angle in the range between 30" and 900 in relation to the outer surface. This achieves an optimization of the bearing pressure on the bearing between the drill bit and the tool support. It is particularly preferable for this angular range to lie between 50 and 700. This also produces an outer surface of the drilling tool that is functional 15 and easy to shape. The object of the invention is also attained with a drill bit for coupling to a drill bit support in rotary fashion. The drill bit has an outer surface that is equipped with hard material elements. The drill bit also has a bearing receptacle. In the region 20 of the bearing receptacle, the drill bit according to the invention has labyrinth seal parts, which can be put together with labyrinth seal parts of the drill bit support to form a labyrinth seal. This labyrinth seal counteracts the penetration of rock material, thus using simple means to effectively protect the bearing receptacle from wearing action. 25 In order to also maintain a reliable position-fixing relative to the drill bit support, even when there are abrupt and uneven loads on the drill bit, it is possible according to the invention for the bearing receptacle to have an end surface that 7 supports a support element composed of hard material. This support element can cooperate with a counterpart support element or a counterpart surface of the drill bit support. 5 The invention will be explained in greater detail below in conjunction with an exemplary embodiment shown in the drawings. Fig. 1 is a perspective side view of a drill head with a tool holder and, mounted thereon, drill bit supports with drill bits; 10 Fig. 2 shows a partial section through the drill head according to Fig. 1; Fig. 3 is a perspective front view of a drill bit support; 15 Fig. 4 is a perspective front view of a drill bit support with drill bits mounted thereon; Fig. 5 is a sectional detail labeled V - V in Fig. 2; 20 Fig. 6 is a perspective side view of a second embodiment variant of a drill head with a tool holder and, mounted thereon, drill bit supports with drill bits; Fig. 7 shows a partial section through the drill head according to Fig. 6; 25 Fig. 8 is a perspective front view of a drill bit support; Fig. 9 is a sectional detail labeled IX - IX in Fig. 7; 30 8 Fig. 10 shows a full section through the drill bit support according to Fig. 8. Fig. 1 shows a drill head with a tool holder 10, whose base part is a support structure 12. The support structure 12 has a downward-pointing fastening shank 5 11 integrally formed onto it. The fastening shank 11 has a conical external thread. The support structure 12 is equipped with three tool sockets 13, which protrude from the outside of the support structure 12 offset from one another by 1200 and are embodied in the form of pockets. 10 Fig. 5 depicts the embodiment of the tool sockets 13 in greater detail. As this drawing shows, each tool socket 13 has two guide projections 13.1 on the outside. The guide projections 13.1 are each provided with a respective guide groove 13.2, the guide grooves 13.2 of a tool socket 13 are situated on opposite sides from each other. The guide grooves 13.2 are delimited laterally by flanks 15 13.3 that are oriented at an angle to each other, preferably in the range between 800 and 1000. This angular range ensures a reliable and jam-free function of the guide. The two guide projections 13.1 form convex surfaces on the outside, which lie along a pitch circle, as shown in Fig. 5. 20 Fig. 1 shows that in the region of the fastening shank 11, the guide projections 13.1 are connected by means of a transition section. This transition section is provided with a screw receptacle 12.1, as shown in Fig. 2. This screw receptacle 12.1 serves to accommodate a fastening screw 12.2. The screw receptacle 12.1 is let into the support structure 12 so that on the one hand, it feeds into the tool 25 socket 13 and on the other hand, it is oriented toward the free end of the fastening shank 11. In this way, the head of the fastening screw 12.2 is 9 accommodated in a protected way, on the side oriented away from the advancing direction of the drill head. The support structure 12, as is also shown in Fig. 2, has a mud channel 15 passing through it. This mud channel 15 feeds into a nozzle. The nozzle 15.1 transitions into a channel chamber 14, which feeds into 5 the outlet channels 14.1. These outlet channels 14.1 are each situated between the guide projections 13.1 of adjacent tool sockets 13. Drill bit supports 20 can be mounted in the tool sockets 13. The design of the drill bit support 20 is shown in greater detail in Fig. 3. As this depiction shows, the drill 10 bit support 20 has an insertion lug 21. This insertion lug terminates with an inner surface 24 and on the outside, with a convex outer surface 25. Rib-like guide pieces 22 are integrally formed onto the sides of the insertion lug 21. The guide pieces 22 have two guide surfaces 22.1 oriented at an angle to each other so that the guide pieces 22 taper from their connecting region to the insertion lug 21 15 toward their free end. The inclination angle is selected in accordance with the angle between the flanks 13.3. The guide surfaces 22.1 transition into one another via a connecting section 22.2. In the region of the free end of the insertion lug 21, a support lug 23 is formed, which is embodied as a transition section and, like the guide pieces 22, is embodied as rib-like. The support lug 23 20 transitions flush into the guide pieces 22; it therefore has the same cross sectional geometry. Consequently, it has guide surfaces 23.1 that are inclined in relation to each other. These are in turn connected to each other by means of a connecting section. 25 The insertion lug 21 has a support head 26 with a bearing section 26.3 formed integrally onto it. In the transition region to the bearing section 26.3, the support head 26 has an annular shoulder 26.1 extending around it, which is adjoined by a 10 circumferential groove 26.2. The shoulder 26.1 and the groove 26.2 constitute labyrinth seal parts. The cylindrical bearing section 26.1 is first adjoined by a concave transition 26.4 in order to adapt its size to a reduced-diameter connector piece at the end. A circumferential groove 26.5 is incorporated into this connector 5 piece. The bearing section 26.3 terminates at its end with an end surface 26.7. As shown in Fig. 2, this end surface 26.7 has a recess incorporated into it, into which a support element 26.6, composed of a hard material such as a hard metal, is soldered, glued, or press-fitted. Fig. 2 also shows that an annular clamping element 29.1 in the form of a round wire snap ring is snapped into the 10 circumferential groove 26.2. Figs. 2 and 4 show that a drill bit 30 can be connected to the drill bit support 20. The drill bit 30 has an outer surface 31 with at least one circumferential groove 32, 33. Hard material elements 34, in particular hard metal elements, can be 15 soldered into holes on the outer surface 31. The drill bit 30 has an internal bearing receptacle 37. This bearing receptacle 37 is embodied in the form of a hole in the drill bit 30. The bearing receptacle 37 transitions via a diameter reduction into a blind hole bore that is equipped with a groove 38. The blind hole bore terminates with an end surface, in which a recess for a support element 39 20 is provided. The support element 39 can be composed of a hard material such as hard metal. In the end region of the bearing receptacle 37, the drill bit 30 is provided with a circumferential groove 35 and adjoining this groove, a circumferential shoulder 36. The groove 35 and the shoulder 36 are labyrinth seal parts. To mount the drill bit 30 on the drill bit support 20, a bearing 29 is 25 inserted into the bearing receptacle 37 of the drill bit 30 and slid onto the bearing 11 section 26.3 of the drill bit support 20. The bearing 29 in this case is embodied as a needle bearing, making it possible to achieve a small overall height. As shown in Fig. 2, a radial shaft sealing ring or a similar circumferential seal 28 5 is also inserted in the region between the bearing receptacle 37 and the bearing section 26.3. In the inserted state, the circumferential shoulder 36 of the drill bit 30 protrudes into the circumferential groove 26.2 of the drill bit support 20. In the same way, the circumferential shoulder 26.1 of the drill bit support 20 protrudes into the circumferential groove 35 of the drill bit 30, so that a labyrinth seal is 10 formed here. Consequently, the circumferential shoulders 36 and 26.1 and the grooves 26.1 and 35 constitute formed-on seal profiles or labyrinth profiles. Adjacent to the labyrinth seal, the seal 28 seals the bearing receptacle 37 so that the labyrinth seal and the seal 28, effectively protect the bearing 29 from the penetration of rock material and mud emulsion. This prevents premature failure 15 of the bearing 29. In order to affix the drill bit 30 to the drill bit support 20, the clamping element 29.1 simultaneously engages in the grooves 26.5 and 38 of both the drill bit support 20 and the drill bit 30. This produces a form-locked engagement between these components. In addition, the drill bit 30 is supported with its support element 39 on the support element 26.6 of the drill bit support 20. 20 During assembly of the drill bit 30, the clamping element 29.1 slides between the bearing receptacle 37 and the region of the bore that accommodates the groove 38. As a result, the clamping element 29.1 is compressed radially inward into the groove 26.2 and its diameter is reduced. The clamping element 29.1 can then snap into the groove 38 so that a form-locked connection is achieved. 25 The tool combination composed of the drill bit support 20 and drill bit 30 can be inserted into a tool socket 13 of the tool holder 10. For this purpose, the insertion lug 21 is slid into the tool socket 13, which is embodied in the form of an insertion 12 socket. In the process of this, the guide surfaces 22.1 of the guide pieces 22 slide along the flanks 13.3 of the guide grooves 13.2. The insertion movement of the drill bit support 20 is limited by the support surfaces 23.2. These come to rest against corresponding counterpart surfaces of the tool sockets 13. Then the 5 fastening screw 12.2 can be inserted through the screw receptacle 12.1 and screwed into a threaded hole 21.1 of the insertion lug 21. Fig. 5 shows the joined pair of the insertion lug 21 and the tool socket 13. As this drawing shows, the guide surfaces 22.1 rest against the flanks 13.3. The convex outer surface 25 of the insertion lug 21 transitions flush into the convex outer sections of the guide 10 projections 13.1, thus avoiding an abrupt cross-sectional change in favor of a tool design that is optimized in terms of wear. As clearly shown in Fig. 5, the guide projections 13.1 are spaced farther apart from the outer surface 25 than from the inner surface 24, which is illustrated in 15 Fig. 5 with the dimensions a and b, where a is smaller than b. Correspondingly, there is a certain wear volume available in the region of the outer surface of the insertion lug 21, which can wear down during use of the tool without significantly influencing the fastening region between the insertion lug 21 and the tool socket 13. The cross-section of the insertion lug 21 is thus asymmetrical to its central 20 transverse plane Q extending in the longitudinal direction of the insertion lug. Consequently, the tool sockets 13 are also asymmetrical. After all three drill bit supports 20 are fastened to the tool holder 10, the drill head is ready for use. During engagement of the tool, the tool holder 10 and with it, the 25 drill bit support 20, rotates around the rotation axis R. As this occurs, the drill bits 30 come into engagement with the material to be removed. Because of the 13 rotating motion, the drill bits 30 roll in the drilling hole and the hard material elements 34 cut into the material to be removed. An emulsion is supplied via the mud channel 15, which is sprayed out in the region of the nozzle 15.1. The emulsion flushes out the removed and crushed material, whereupon the 5 emulsion then flows out via the outlet channels 14.1. The drill bits 30 are designed differently from one another in the region of their outer surface 31 so that the rotating rows of hard material elements 34 of one drill bit 30 can travel in a respective groove 32, 33 of the adjacent drill bit 30. 10 During engagement of the tool, the above-described tool combination experiences wear. Consequently, the drill bit 30, the drill bit support 20, and the tool holder 10 undergo continuous wear. Depending on the wear state, according to the invention, the tool holder 10, the drill bit support 20, and the drill bits 30 can each be individually replaced. For tool replacement, the drill head is 15 detached from the drilling lance; to accomplish this, the screw connection between the fastening shank 11 and the drilling lance is disconnected. The drill bit support 20 can then be detached by simply unscrewing the fastening screw 12.2 from the tool holder 10. The drill bit 30 can be pressed out from the drill bit support 20. In the course of this, the clamping element 29.1, due to the geometry 20 of the grooves 26.5 and 35, is deflected radially inward and thus disengages from the groove 35 of the drill bit 30. The drill bit 30 can then be slid off of the drill bit support 20. Figs. 6 through 10 show another design variant of an apparatus according to the 25 invention. In it, parts that are the same have been provided with the same reference numerals so that in order to avoid repetitions, reference can be made to the descriptions above.
14 Fig. 6 once again shows a drill head with a tool holder 10, whose base part is a support structure 12. The support structure 12 has a downward-pointing fastening shank 11 integrally formed onto it. The fastening shank 11 has a conical external thread. The support structure 12 is equipped with three tool 5 sockets 13, which protrude from the outside of the support structure 12 offset from one another by 1200. Fig. 9 gives a clearer depiction of the tool socket 13. As the drawing shows, the support structure 12 has one guide projection 13.1 for each tool socket 13. Each 10 guide projection 13.1 has longitudinal guides in the form of prism guides on opposite sides. The two prism guides here are each formed by two guide surfaces 22.1 oriented at an angle relative to each other. An angle in the range between 450 and 750 between the guide surfaces 22.1 has turned out to be particularly advantageous. This makes it possible to ensure a simple assembly in 15 the rough conditions of worksite operations. In addition, this embodiment of the guide projections 13.1 does not have a tendency to jam. The guide surfaces 22.1 extend in the longitudinal direction of the guides, as shown in Fig. 8 and Fig. 10. The drill bit supports 20 can be fastened to the tool sockets 13. 20 As shown in Fig. 8 and 10, the tool supports 20 have a tool head 26, which is integrally joined to an insertion lug 21. On its radial inside, the insertion lug 21 forms a recessed fastening receptacle. In this case, the fastening receptacle is open toward the radial inside and in the downward direction, as shown in Fig. 3. The fastening receptacle is delimited by flanks 13.3 that are oriented relative to 25 each other in prism fashion. The flanks 13.3 are oriented relative to each other at 15 the same angle as the guide surfaces 22.1 so that the flanks 13.3 and the guide surfaces 22.1 form sliding guides. As shown in Fig. 9, the flanks 13.3 are part of guide pieces 22, that delimit the 5 fastening receptacle toward the front and back in the advancing direction V. The guide pieces 22 each form a respective shoulder 22.2, which supports one of the flanks 13.3 and which engages in a form-locked way behind the guide projection 13.1. As a result, it is no longer possible to offset the drill bit support 20 in the radial direction. Now, the drill bit support 20 can only be slid in the guidance 10 direction. The two guide pieces 22 are connected to each other by means of a wall section 21.2. In the attachment region to the tool holder 12, the guide pieces 22 terminate at inner surfaces 24 that are flush with each other and are situated in one plane. The outside of the tool support 20 is defined by an outer surface 25. This outer surface 25 is divided into a plurality of partial surfaces. In the 15 advancing direction, the outer surface 25 has a first surface section 25.1 which transitions at an angle into a deflecting surface 25.2. The deflecting surface 25.2 is tilted in the opposite direction from the advancing direction V, as shown in Figs. 8 and 9. The deflecting surface 25.2 transitions via a clearing edge 25.6 into a side surface 25.3. The clearing edge 25.6 extends essentially in the 20 direction of the central longitudinal axis of the drill bit support 20. In the opposite direction from the advancing direction V, the side surface 25.3 transitions at the back into an open surface 25.4; between the side surface 25.3 and the open surface 25.4, there is also an edge region. The open surface 25.4 finally ends at a surface section 25.5, which like the surface section 25.1, transitions into the 25 inner surface 24. As shown in Fig. 8 and Fig. 10, a fastening receptacle 21.3 in the form of a bore that passes through the two guide pieces 22 is located in the region of the insertion lug 21. In order to mount the drill bit support 20 on the tool holder 10, 30 16 the flanks 13.3 of the drill bit support 20 in the region of its open underside are placed onto the guide surfaces 22.1. Then, the insertion lug 21 of the drill bit support 20 is slid onto the guide projection 13.1 of the tool socket 13 in the guide direction. The sliding-on movement is limited by a stop 21.4 (see Fig. 10). The 5 stop 21.4 here is likewise embodied in the form of an internal prism in order to produce a form-locked engagement. This cooperates with corresponding prism surfaces of the guide projection 13.1. In the installed state, the fastening receptacle 21.3 is flush with a corresponding bore receptacle in the guide projection 13.1. Then a corresponding fastening element such as a hollow dowel 10 pin can be slid through the flush fastening receptacles 21.3 of the insertion lug 21 and of the guide projection 13.1. This prevents an offset of the tool support 20 relative to the tool holder 10 in the guidance direction. As shown by Fig. 9, the guide piece 22 toward the front in the advancing 15 direction V has a larger wear volume than the rear guide piece 22. Fig. 9 also shows that the structural height of the front guide piece 22 in the radial direction is greater than the structural height of the rear guide piece 22 (distance dimension d2 > di). Consequently, the clearing edge 25.6 lies on a different, namely larger, pitch circle (center of the circle on the rotation axis R) than the 20 edge region between the open surface 25.4 and the side surface 25.3. The side surface 25.3 therefore has a wear-optimized geometry that decreases radially inward in the opposite direction from the advancing direction V, as clearly shown in Fig. 9. 25 The insertion lug 21 supports a tool head 26, which once again has a bearing section 26.3 integrally formed onto it.
17 The embodiment of the tool head 26 and drill bit 30 is selected to be essentially identical to that of the first design variant according to Figs. 1 through 5, so that reference can be made to the explanations above. 5 10 15 20