Hartmetalleinsatz und Gesteinsbohrer

Abstract

The invention relates to a carbide insert (2) for a rock drill (1), which is configured as a non-percussively operating twist drill with a cylindrical drill body (11) and a working end (13) having the carbide insert (2), the carbide insert (2) having two cutting lips (22) which are radially opposite one another relative to an axis of drill rotation (d) and are arranged at an angle to one another to form a centering tip (21) and with each of which a peripheral conveyor spiral (14) may be associated. To be able to introduce a drilled hole more quickly, easily and simply and with less risk of damage into a workpiece of rock, rock-like material, hard plastics, glass or the like, it is proposed that the cutting lips (22) be configured asymmetrically to one another, wherein at least one of the cutting lips (22) defines over its radial profile, in a central region spaced from its radial ends, a tip (23) projecting in the drilling direction (b).

Claims

1. A carbide insert (2) for a rock drill (1), which is configured as a non-percussively operating twist drill for drilling rock, rock-like material, hard plastics, glass or the like with a cylindrical drill body (11) and a working end (13) having the carbide insert (2), the carbide insert (2) comprising: two cutting lips (22) which are radially opposite one another relative to an axis of drill rotation (d) and are arranged at an angle to one another to form a centering tip (21) and with each of which a peripheral conveyor spiral (14) is associated, the cutting lips (22) being configured asymmetrically to one another, at least one of the cutting lips (22) defining over its radial profile, in a central region spaced from its radial ends, a tip (23) projecting in the drilling direction (b), the centering tip (21) being axially symmetrically tapered relative to the axis of drill rotation (d) and the carbide insert being of plate-shaped configuration, a first flute-like recess (271) in a leading position relative to a cutting edge (25) of one of the cutting lips (22) in the direction of drill rotation (r) and extending into the associated conveyor spiral (14) is introduced (A5) radially inwardly and/or a second flute-like recess (272) in a leading position relative to a cutting edge (25) of the other cutting lip (22) in the direction of drill rotation (r) and extending into the associated conveyor spiral (14) is introduced (A5) radially outwardly into the drill body (11), and in that the two recesses (271, 272) each form a profile portion of the associated cutting lip (22) and adjoin one another radially, so forming a discontinuity in the radial profile of the cutting lip (22).

2. The carbide insert (2) as claimed in claim 1, wherein the tip (23) of at least one cutting lip (22) is defined radially inwardly and radially outwardly by an uncurved or by a concavely curved free-running surface (24).

3. The carbide insert (2) as claimed in claim 1, wherein the tip (23) divides the cutting lip (22) into a radially outer portion (a1) and a radially inner portion (a2), the ratio of the length of the outer portion (a1) to that of the inner portion (a2) is 1.

4. (canceled)

5. (canceled)

6. (canceled)

7. The carbide insert (2) as claimed in claim 1, wherein the discontinuity formed by the mutually adjoining recesses (271, 272) is arranged at a radial point (P) of one cutting lip (22) which is different from the free end point of the tip (23) of this cutting lip (22).

8. The carbide insert (2) as claimed in claim 7, wherein the point (P) with the discontinuity of one cutting lip (22) formed by the mutually adjoining recesses (271, 272) is arranged radially inwardly relative to the tip (23) of this cutting lip (22).

9. The carbide insert (2) as claimed claim 8, wherein the first recess (271) and/or second recess (272) are arranged in the drilling direction (b) angled towards the axis of drill rotation (d) at an angle to same.

10. The carbide insert (2) as claimed in claim 9, wherein the two cutting lips (22) each have the tip (23) projecting in the drilling direction (b), wherein the tip (23) of the one cutting lip (22) is arranged at a first radius (r1) which is different from a second radius (r2) of the tip (23) of the other cutting lip (22).

11. The carbide insert (2) as claimed in claim 10, wherein the tip (23) of one cutting lip (22) is arranged on the radially inner half of the cutting lip (22) and the tip (23) of the other cutting lip (22) is arranged on the radially outer half of the other cutting lip (22).

12. The carbide insert (2) as claimed in claim 11, wherein the centering tip (21) has a centering angle () which amounts for drilling of glass to 50 to 70, wall tiles to 70 to 80 or floor tiles, thermosets and hard composites to 110 to 140.

13. (canceled)

14. A rock drill (1) configured as a non-percussively operating twist drill for drilling rock, rock-like material, hard plastics, glass or the like, wherein the rock drill (1) has a cylindrical drill body (11) and a working end (13) with a carbide insert (2) as claimed in claim 1.

15. The rock drill (1) as claimed in claim 14, wherein the carbide insert (2), includes a first flute-like recess (271) in a leading position relative to the cutting edge (25) of the cutting lip (22) in the direction of drill rotation (r) and extending into the associated conveyor spiral (14) is introduced radially inwardly and/or a second flute-like recess (272) in a leading position relative to the cutting edge (25) of the cutting lip (22) in the direction of drill rotation (r) and extending into the associated conveyor spiral (14) is introduced radially outwardly into the drill body (11), wherein the recesses (271, 272) of the cutting lip (22) extend contrary to the drilling direction (b) to the conveyor spiral (14) associated with this cutting lip (22) or lead into the conveyor spiral (14) associated with this cutting lip (22).

16. The rock drill (1) as claimed in claim 15, wherein the first recess (271) of the cutting lip (22) leads, contrary to the drilling direction (b), into the second recess (272) associated with this cutting lip (22) and the second recess in turn leads, contrary to the drilling direction (b), into the conveyor spiral (14) associated with this cutting lip (22).

17. The carbide insert (2) as claimed claim 1, wherein the first recess (271) and/or second recess (272) are arranged in the drilling direction (b) angled towards the axis of drill rotation (d) at an angle to same.

18. The carbide insert (2) as claimed in claim 17, wherein the two cutting lips (22) each have the tip (23) projecting in the drilling direction (b), the tip (23) of one cutting lip (22) is arranged at a first radius (r1) which is different from a second radius (r2) of the tip (23) of the other cutting lip (22).

19. The carbide insert (2) as claimed in claim 18, wherein the tip (23) of one cutting lip (22) is arranged on the radially inner half of the cutting lip (22) and the tip (23) of the other cutting lip (22) is arranged on the radially outer half of the other cutting lip (22).

20. The carbide insert (2) as claimed in claim 19, wherein the centering tip (21) has a centering angle () which amounts for drilling of glass to 50 to 70, wall tiles to 70 to 80 or floor tiles, thermosets and hard composites to 110 to 140.

21. The carbide insert (2) as claimed in claim 17, wherein the two cutting lips (22) each have the tip (23) projecting in the drilling direction (b), the tip (23) of the one cutting lip (22) is arranged at a first radius (r1) which is different from a second radius (r2) of the tip (23) of the other cutting lip (22).

22. The carbide insert (2) as claimed in claim 1, wherein the two cutting lips (22) each have the tip (23) projecting in the drilling direction (b), the tip (23) of the one cutting lip (22) is arranged at a first radius (r1) which is different from a second radius (r2) of the tip (23) of the other cutting lip (22).

23. The carbide insert (2) as claimed in claim 1, wherein the tip (23) divides the cutting lip (22) into a radially outer portion (a1) and a radially inner portion (a2), wherein the ratio of the length of the outer portion (a1) to that of the inner portion (a2) is .

24. The carbide insert (2) as claimed in claim 1, wherein the tip (23) divides the cutting lip (22) into a radially outer portion (a1) and a radially inner portion (a2), the ratio of the length of the outer portion (a1) to that of the inner portion (a2) is .

Description

[0030] The present invention is explained in greater detail below with reference to a number of embodiments depicted in drawings of the carbide insert or of the rock drill with carbide insert, without however limiting the invention to said embodiments. In the drawings:

[0031] FIGS. 1 and 1a respectively show side views of a rock drill with a carbide insert according to FIG. 3 and an enlarged detail Ia according to FIG. 1,

[0032] FIGS. 2 and 2a respectively show another side view of the rock drill according to FIG. 1 and an enlarged detail IIa according to FIG. 2,

[0033] FIGS. 3a to 3h each show a view of the carbide insert shown in FIGS. 1 and 2,

[0034] FIGS. 4a to 4d each show a view of a further embodiment of the carbide insert,

[0035] FIGS. 5a to 5c each show a view of a further embodiment of the carbide insert,

[0036] FIGS. 6a and 6b respectively show a view of a further embodiment of the carbide insert and an enlarged detail thereof,

[0037] FIGS. 6c and 6d respectively show a view of a further embodiment of the carbide insert and an enlarged detail thereof,

[0038] FIGS. 7a to 7e each show a view of a further embodiment of the carbide insert and

[0039] FIGS. 8a to 8e each show a view of a further embodiment of the carbide insert.

[0040] FIGS. 1 and 2 each show a side view of a rock drill 1, which is configured as a non-percussively operating twist drill for drilling rock, rock-like material, hard plastics, glass or the like with a cylindrical drill body 11 and a working end 13 having a receptacle 12, a plate-shaped carbide insert 2 according to the embodiments shown in FIGS. 4a-4e being brazed into the receptacle 12. FIGS. 3 and 5-8 show further embodiments of the carbide insert 2 in various views and in part with associated enlarged details.

[0041] As is apparent from the enlarged details of FIGS. 1a and 2a associated respectively with FIG. 1 and FIG. 2 and from the other FIGS. 3-8, the carbide insert 2 has cutting lips 22 which are radially opposite one another relative to an axis of drill rotation d and are arranged at an angle to one another to form a centering tip 21. Each cutting lip 22 has a conveyor spiral 14 associated with it, by which the cut material, not shown here, cut away by the carbide insert 22 is transported away contrary to drilling direction b. (In the figures, in the case of larger, curved side faces, additional lines with a smaller line thickness are drawn in which do not indicate a contour but rather a depth profile of these side faces.)

[0042] The cutting lips 22 are asymmetric to one another in all the embodiments of the carbide insert 22, wherein at least one of the cutting lips 22 defines over its radial profile, in a central region spaced from its radial ends, a tip 23 projecting in the drilling direction b thereof. The tip 23 represents a discontinuity in the radial profile of the cutting lips 22. In all the embodiments, a single projecting tip 23, where provided, is arranged in the cutting lip 22. The tip 23 projecting in the drilling direction b, as described above, generates a transverse force during drilling, which forces the rock drill into transverse motion perpendicular to the drilling direction b and rotating with the drill, whereby the material at the bottom of the drilled hole is removed more quickly and moreover in the form of finer to floury grains, without percussive drilling being used.

[0043] The tip 23 extends over the entire cutting lip 22 and ends at a specific radius with its free end in an end point. The tip 23 thus rises over the entire cutting lip 22 from both radial sides to the free end point.

[0044] In the embodiments of the carbide insert 2, the tip 23 is defined radially inwardly and radially outwardly by free-running surfaces 24 of the cutting lip 22. The free-running surfaces 24 may here, as shown by way of example in FIGS. 1-4 and 7, be uncurved side faces which slope away from the cutting edge 25 of the cutting lip 22 in each case at a specific wedge angle to the axis of drill rotation d contrary to drilling direction b. With regard to a radial axial plane, which in FIG. 3f is the same as the image plane, the cutting lip 22 has a gable-like profile. In FIG. 3f, to clarify the roof-like profile of the cutting lips 22 with the tip 23, the profile of the cutting lip 22 without tip 23 on the right here is shown reflected by dash-dotted lines and denoted 22. These two profiles form a triangle with a height h. It is immediately clear from the drawing that the smaller the internal angle formed by the tip 23 and the greater the height h of the triangle drawn, the greater is the transverse force caused by the tip 23 during drilling. The cutting edge 25 of the cutting lip 22 with tip 23 is formed by the associated free-running surface 24 and the side face 26 sloping away contrary to the drilling direction b and pointing in the direction of drill rotation r. The tip 23 thus takes the shape of a three-sided pyramid with the two free-running surfaces 24 and the side face 26 as side faces of said pyramid. The proportions shown in the figures are however merely by way of example and it is not intended to limit the disclosure content of the invention thereto.

[0045] Alternatively, the free-running surfaces 24 defining the tip 23 may be concavely curved, as shown by way of example in FIGS. 5 and 8. As in FIG. 3f, in FIG. 5a the profile of the cutting lip is shown in a side view perpendicular to the radial axial plane, which at the same time is the image plane of FIG. 5a. According thereto, the profile is gable-like but with curved gable sides, i.e. with two concave arcs converging at the tip. The exact profile is introduced using cylindrical grinding wheels, wherein the wedge angle is defined at the same time thereby. Thus, compared to the embodiments of the carbide insert 2 with uncurved free-running surfaces 24, a sharper tip 23 is produced, which is more aggressive in action but more susceptible to wear.

[0046] As is clearly apparent in particular from FIGS. 3f and 5a, the tip 23 divides the cutting lips 22 into two radial portions, i.e. a radially outer portion a1 and a radially inner portion a2, wherein the ratio of the length of the outer portion a1 to that of the inner portion a2 here amounts to around 1.5.

[0047] In contrast to the embodiments of the hard metal insert 2 according to FIGS. 1-6, those in FIGS. 7 and 8 have just one tip 33 in leading position in the direction of drill rotation r on each of the two cutting lips 32, wherein the tips 33 are however arranged at different radii, i.e., as shown in FIG. 7a, the left-hand tip 33 is arranged at a first radius r1 and the right-hand tip 33 at a second radius r2, wherein the first radius r1 is here about half as large as the second radius r2. The tip 33 on the right hand here, due to its greater radial lever (r2), thus causes a greater transverse force to be generated than the left-hand tip 33.

[0048] The centering tip 21 is axially symmetrically tapered relative to the axis of drill rotation d. To this end, a first flute-like recess 271 in a leading position relative to the cutting edge 25 of the cutting lips 22 in the direction of drill rotation r and extending to the associated conveyor spiral 14 of the respective cutting lip 22, is provided radially inwardly for each cutting lip 22. The first recess 271 is introduced into the carbide insert 2, forming an inner region and thus parallel to this inner region. The cutting lip 22 is thus extended into the centering tip 21 and it is moreover ensured that cut-off material may be discharged from the centering tip 21 into the respective conveyor spiral.

[0049] Furthermore, the first recess 271 is arranged inclined at an angle of attack to the axis of drill rotation d. As is apparent for example from FIG. 6c or 6d, the two cutting lips 22 extend radially inwards, forming a transverse lip 28, wherein they are radially spaced by way of the transverse lip 28, depending on the size of the angle of attack . A comparison of FIGS. 3a, 6a and 6c shows that, the greater the angle of attack or the further the first recesses 271 extend relative to the axis of drill rotation d, the smaller is the transverse lip 28. The inclination of the first recess 271 may thus be used purposefully to adjust the size of the transverse lip 28 and thus also the radial thickness of the centering tip 21. The first flute-like recess 271 forms the radially inner region 221 of the one cutting lip 22 and a radially inner region 241 of a free-running edge 242 defining the free-running surface 24 of the other cutting lips 22.

[0050] In the embodiments of the rock drill 1 or of the carbide insert 2 illustrated here, the centering angle amounts to around 120 and is thus suitable in particular for drilling floor tiles, thermosets, hard composites and the like.

[0051] In the embodiments of the carbide insert 2 according to FIGS. 6-8, in addition to the first recess 271, a second recess 272 is provided radially outwardly and extending to the cutting edge 25 for further improved removal of cut material, said second recess extending towards the respectively associated conveyor spiral 14 contrary to the drilling direction b. The two recesses 271, 272 of a cutting lip 22 adjoin one another, forming a discontinuity in the radial profile of the associated cutting lips 22 which likewise contributes to comminution of the cut material. In a manner favorable to maximum comminution, it is here provided that, in all the embodiments of the carbide insert 2 shown here, the radial point P at which the two recesses 271, 272 adjoin one another radially is different from the point at which the tip 23 ends at its free end.

[0052] In order to ensure maximally free flow of the cut-off material from the carbide insert 2 into the respective conveyor spiral 14 of the rock drill 1, a cut-away portion 29 is provided (in particular in FIGS. 1, 1a, 2 and 2a and in the views from below according to FIGS. 3e and 4e) axially in the drilling direction b in a trailing position relative to the cutting lip 22, wherein that cut-away portion merges into the associated conveyor spiral virtually without transition contrary to the drilling direction b, i.e. without any side face pointing in the drilling direction b and projecting away into the convey spiral 14 for transporting the material away. That is to say, in the embodiments of the carbide insert 2 shown here, all that has been provided is an offset which is harmless to material flow at the point of transition of the carbide insert 2 into the conveyor spiral 14.

[0053] Insofar as a second recess 272 is provided, same conveys the cut material contrary to drilling direction b into the associated cut-away portion 29. In addition, the first recess 271 guides the cut material into the associated second recess 272 and radially inwards directly into the associated cut-away portion 29. Comprehensive removal of the cut material into the associated conveyor spiral 14 is thus made possible.

[0054] The carbide insert 2 is dimensioned radially and arranged in the receptacle 12 in such a way that it terminates radially outwardly flush with the drill body 11.

LIST OF REFERENCE NUMERALS

[0055] 1 Rock drill [0056] 11 Drill body [0057] 12 Receptacle [0058] 13 Working end [0059] 14 Conveyor spiral [0060] 2 Carbide insert [0061] 21 Centering tip [0062] 22 Cutting lip [0063] 221 Inner region (cutting lip) [0064] 23 Tip [0065] 24 Free-running surface [0066] 241 Inner region, free-running surface [0067] 25 Cutting edge [0068] 26 Side face (cutting edge) [0069] 271 First recess [0070] 272 Second recess [0071] 28 Transverse lip [0072] 29 Cut-away portion [0073] Internal angle [0074] Centering angle [0075] Angle of attack [0076] a1 Outer portion [0077] a2 Inner portion [0078] b Drilling direction [0079] d Axis of drill rotation [0080] h Height [0081] r Direction of drill rotation [0082] r1 First radius [0083] r2 Second radius [0084] P Point