5-flute rock drill

Abstract

The present invention relates to a rock drill (10) including a shank portion (12) having an insert portion (16) formed at one end for connection to a tool holder of a drilling machine tool and a drill head (18) formed at the other end for machining a substrate. The drill head (18) has at least one cutting edge (20) having a projection (22) at its outer end that points tangentially from the cutting edge (20) relative to the longitudinal axis (L). The rock drill (10) has a high removal rate and a low risk of clogging.

Description

[Technical Field]

[0001] The present invention begins with a masonry drill including a shaft portion on which a shank portion is formed at one end for connection to a tool fixture of a power drill and a drill head is formed at the other end for machining a substrate, the drill head having at least one blade extending outward from a central longitudinal axis of the drill head. [Background technology]

[0002] This type of masonry drill is typically used to drill holes in concrete, for example, for processing concrete, including reinforced concrete.

[0003] During this process, the masonry drill can become stuck in the concrete, etc. This occurs particularly frequently when the masonry drill comes into contact with reinforcing material, such as reinforced concrete.

[0004] This can cause damage to the power tool on which the masonry drill is attached and / or injury to the user of the power tool or masonry drill. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to provide a masonry drill that allows safe drilling, particularly in concrete, etc. It is also desirable for the masonry drill to achieve a high drilling rate. [Means for solving the problem]

[0006] This object is achieved by a masonry drill comprising a shaft portion formed at one end with a shank portion for connection to a tool fixture of a power drill and at the other end with a drill head for machining a substrate, the drill head having at least one blade extending outwardly from a central longitudinal axis of the drill head, the blade having a protrusion at its outer end pointing tangentially from the blade to the longitudinal axis.

[0007] The idea behind this is that the masonry drill will get stuck in reinforced concrete etc., especially if the reinforcement can get stuck between the blades of the drill head. It is therefore advantageous to fill as much of the volume of the interspace between the blades as possible, or to keep the interspace as small as possible overall.

[0008] In particular, the intermediate space can be reduced in size by one or more protrusions, which at the same time may not affect the effective contact area and therefore the specific impact force and resulting removal capability.

[0009] A larger number of blades allows the masonry drill to be guided in a more stable manner during the drilling process, further reducing the risk of the reinforcement getting stuck between the blades which are formed closer to each other.

[0010] Therefore, in principle, it may be advantageous to provide multiple blades on the drill head. However, an increased number of blades also increases the contact area between the drill head and the substrate, i.e., reinforced concrete, etc. This reduces the specific impact force over the contact area for the same impact energy per impact and impact frequency of the power tool to which the masonry drill is attached. Therefore, the removal capacity of the masonry drill may decrease with an increased number of teeth.

[0011] Based on past experience, it has been found that a particularly favorable balance between clogging tendency, stability and removal ability is obtained when the drill head has at least three, preferably a maximum of seven, and particularly preferably five blades extending outward from the central longitudinal axis of the drill head.

[0012] Each blade may have a projection at its outer end pointing away from the respective blade in a direction tangential to the longitudinal axis, thus enabling the size of the intermediate space between adjacent blades to be further reduced.

[0013] The masonry drill therefore allows drilling operations with no or only minimal risk of jamming and therefore particularly safe operations.

[0014] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the invention, with reference to the drawing figures showing details essential to the invention, and from the claims. The features shown therein should not necessarily be considered to be to scale, but are shown so as to clearly show the particular features according to the invention. The various features can be implemented individually by themselves or collectively in any combination in variants of the invention.

[0015] Exemplary embodiments of the invention are shown in schematic drawings and are explained in detail in the following description, in particular the features recited in the dependent claims will also be explained with reference to the drawings. [Brief explanation of the drawings]

[0016] [Figure 1] 1 shows a side view of a masonry drill. [Figure 2] 1 shows a perspective view of a masonry drill. [Figure 3] 1 shows another perspective view of the masonry drill. [Figure 4] 1 shows a plan view of the drill head of a masonry drill. [Figure 5]1 shows a perspective view of a masonry drill, particularly the front portion of the drill head. [Figure 6] 1 shows a side view of a shaft portion of a masonry drill and of a portion of the drill head adjacent the drill head. [Figure 7] 1 shows a side view of a shaft portion of a masonry drill and of a portion of the drill head adjacent the drill head. [Figure 8] 1 shows a side view of a shaft portion of a masonry drill and of a portion of the drill head adjacent the drill head. [Figure 9] 1 shows a side view of a shaft portion of a masonry drill and of a portion of the drill head adjacent the drill head. [Figure 10] 7 shows a side view of a masonry drill corresponding to the view shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following description of the drawings, the same reference numbers are used in each case for identical or functionally corresponding elements to facilitate an understanding of the invention.

[0018] 1 shows a side view of a masonry drill 10. The masonry drill 10 includes a shaft portion 12. A feed helix 14 is formed on the shaft portion 12.

[0019] A shank portion 16 is formed at one end of the shaft portion 12 for connection to a tool fixture of a power drill (not shown in FIG. 1), and a drill head 18 is formed at the other end for machining a substrate (not shown in FIG. 1), such as reinforced concrete.

[0020] The shank portion 16 is, for example, in the form of a shank commonly known as "SDS Max." It is also possible for the shank to be in the form of an "SDS Plus" or similar standardized shank.

[0021] The feed helix 14 is designed as a double-start helix. Alternatively, it would be conceivable to design the feed helix as a three-, four-, or five-start helix. A double-start helix can transport removed concrete or the like from the drill head 18 at a high transport rate. This may be suitable for manufacturing at an acceptable cost, despite being a relatively robust design. The helix spacing is sufficiently far apart to ensure that even relatively large particles, such as removed concrete, can be transported along the feed helix without clogging. Therefore, a feed helix 14 designed as a double-start helix has been found to be particularly advantageous.

[0022] The drill head 18 has five blades 20. For clarity, only one blade 20 is labeled.

[0023] The blade 20 extends outwardly from a central longitudinal axis L of the drill head 18. It should be understood that the masonry drill 10 can also be operated in an impact mode, particularly along the longitudinal axis L, to remove concrete and the like. Thus, generally, the masonry drill 10 can be operated in a rotational impact mode to remove concrete and the like.

[0024] The masonry drill 10 can be designed for boreholes having diameters of at least 10 mm and / or up to 32 mm, thus ensuring sufficient thickness of material at all points regardless of the particular geometry, as described in detail below.

[0025] Furthermore, such dimensions allow the weight, and therefore the inertia associated with the weight, to remain within a range suitable for removing concrete and the like by rotational impact.

[0026] The drill head 18 preferably comprises a material that is more resistant to breakage than the shaft portion 12. The shaft portion 12 may comprise steel, while the drill head may comprise a hard metal, for example a tungsten-based hard metal.

[0027] 2 and 3 show additional perspective views of the masonry drill 10, which allow for additional views of, among other things, the feed helix 14, the shank portion 16, and the drill head 18.

[0028] Figure 4 shows a plan view of the drill head 18. Five blades 20 are visible.

[0029] Each of the blades 20 has at its outer end a projection 22 pointing away from the respective blade 20 in a direction tangential to the longitudinal axis L. Again, for clarity, only one of the projections 22 is labeled.

[0030] For example, as can be seen in FIG. 4, the projections 22 pointing from each blade 20 in a direction tangential to the longitudinal axis L each have at least one main direction H, which has at least one major directional component in the tangential direction.

[0031] The tips of the prongs 22 point along a circumferential direction U, which corresponds to the direction of motion of the masonry drill 10 as it rotates to remove substrate. Thus, the prongs 22 always move somewhat ahead of their associated blades 20 during removal of concrete, etc.

[0032] Alternatively or additionally, it is also conceivable that the tip of at least one of the projections 22 points in opposite circumferential directions, ie, so that it tends to follow the corresponding blade 20 each time.

[0033] In particular, in the case of an alternative masonry drill, at least one of the blades 20 may be provided with leading and trailing projections 22 .

[0034] By means of the projections 22, the intermediate spaces 24 between each adjacent blade 20, only one of which is also indicated by reference numeral in, for example, FIG. 4, are reduced in size.

[0035] At the same time, a free space remains in the intermediate space 24 so that the ground material can reach the feed spiral 14 through it.

[0036] The blades 20 project rotationally symmetrically from the center point M of the drill head 18, i.e. in a direction transverse to the longitudinal axis L (see FIG. 1), at an angle alpha of preferably 70° to 80°, in particular 72°. As a result of the rotationally symmetric arrangement, the contact between the substrate and the drill head 18 is particularly uniformly distributed over the cross section of the drill head 18. As a result, the masonry drill 10 can be introduced in a very stable manner into the substrate to be drilled.

[0037] Blade 20 has cutting edges 26. All but one cutting edge 26, i.e., the cutting edge 26 located approximately at the 1 o'clock position in FIG. 4, i.e., the cutting edge 26 extending diagonally to the upper right, are curved.

[0038] It is also conceivable to form an alternative masonry drill 10 having such cutting edges 26 but without the projections 22. Such an alternative masonry drill 10 may have one or more of the features described above and / or below and / or included in the drawings, excluding features specifically related to the projections 22.

[0039] 5 shows another perspective view of the masonry drill 10. In particular, the end of the masonry drill 10 having its drill head 18 can be seen.

[0040] Two of the five blades 20, in particular their free ends, are retracted rearward relative to their respective adjacent blades 20, i.e., in the direction of the feed helix 14 parallel to the longitudinal axis L. These form secondary blades 28. The drill head 18 therefore first engages the substrate to be drilled with the remaining three blades 20, hereinafter referred to as primary blades 30.

[0041] The secondary blades 28 have a greater curvature perpendicular to the longitudinal axis L than the primary blades 30, thus further improving chip removal.

[0042] This results in a masonry drill 10 with its five blades 20 that has a particularly high specific impact force and, as a result, a particularly high removal capacity.

[0043] Apart from their stabilizing function already explained above, the secondary blades 28 can be used especially when the masonry drill 10 hits a reinforcement, for example a steel reinforcement, and possibly gets within a certain distance of the reinforcement, whereupon the secondary blades 28 can accelerate the removal of the reinforcement.

[0044] 5 further shows that the free ends of the protrusions 22 are set back relative to their ends facing the blade, i.e., towards the feed spiral 14, so that during normal removal of concrete or the like, the protrusions 22 likewise do not strike the substrate, thereby further minimizing the effective contact area in favor of high specific impact forces. Together with the sides of the blade 20, the protrusions 22 also form sliding surfaces along which the crushed material can be guided towards the feed spiral 14, so that the removal of crushed material is also improved by shifting the free ends of the protrusions 22 towards the rear.

[0045] Furthermore, from FIG. 5, as well as from FIGS. 1 to 3, it can be seen that the feed spiral 14 is of a double-start design in order to achieve a high conveying capacity.

[0046] The blades 20 that are not directly adjacent to the helical wall 33 of one of the helical grooves 32 of the feed helix 14 are supported by supports 34 that protrude from the feed helix 14; again, for clarity, only one helical wall 33 is labeled in FIG. 5. The supports 34 are formed independently of the helical wall 33 so as to protrude from the feed helix 14. Thus, one such support 34 is formed for five blades 20 and the double-start feed helix 14.

[0047] The support 34 therefore makes it possible to connect the drill head 18 to a certain number of blades 20 by means of a feed helix 14 having a different number of helical walls 33 than the number of blades 20. In particular, the drill head 18 can be provided with a feed helix 14 having an even number of flutes together with an odd number of blades 20. Therefore, particularly advantageous configurations of the respective drill head 18 can be combined with particularly advantageous configurations of the feed helix 14.

[0048] All blades 20 open into the feed spiral 14 along walls 36, of which only one wall 36 is referenced in Figure 5, again for the sake of clarity. The walls 36 extend parallel to the longitudinal direction L, so that introduction areas 38 are obtained which open into the feed spiral 14 parallel to the longitudinal direction L, again for the sake of clarity only one of which is referenced. The introduction areas 38, and in particular the walls 36 which extend parallel to the longitudinal direction L, serve to further improve the clearance of the debris.

[0049] To ensure the necessary strength of the connection, the drill head 18 can preferably be butt-jointed to the shaft portion 12 by a metallurgical bond zone 40. The metallurgical bond zone 40 can be produced, for example, by welding or brazing.

[0050] 6-9 show several side views of the shaft portion 12 of the masonry drill 10 and of the drill head 18 and a subsection adjacent to the drill head 18 from different viewing angles.

[0051] 6, it can be seen that the blade 20, designated by the reference number 20, is seated on a support 34. The support 34 itself is designed to protrude from the feed spiral 14. It is located between two spiral walls 33 of one of the spiral grooves 32.

[0052] Such support of the blade 20 by the support 34 can be provided for both blades 20 with tangential protrusions and blades 20 without tangential protrusions. By way of example, blades 20 without tangential protrusions are shown in Figures 6-9.

[0053] In a view corresponding to FIG. 6, FIG. 10 shows a partial section of a masonry drill 10 in which the blades 20 have tangential projections 22, and again only one blade 20 and associated projection 22 are indicated by reference numeral. [Explanation of symbols]

[0054] 10 Mason Redrill 12 Shaft part 14 Feed spiral 16 Shank part 18 Drill Head 20 blades 22 protrusions 24 Intermediate Space 26 cutting edge 28 Secondary Blade 30 Main Blade 32 Spiral groove 33 spiral wall 34 Support 36 Wall 38 Introduction area 40 Metallurgical bonding zone H Main direction L longitudinal axis M center point U Circumferential direction Alpha Angle

Claims

1. A masonry drill (10) comprising a shaft portion (12) having a shank portion (16) formed at one end for connection to a tool fixture of a power drill and a drill head (18) formed at the other end for machining a substrate, said drill head (18) having at least one blade (20) extending outwardly from a central longitudinal axis (L) of said drill head (18); The masonry drill (10) is characterized in that the blade (20) has a projection (22) at its outer end that points away from the blade (20) in a direction tangential to the longitudinal axis (L).

2. 2. The masonry drill according to claim 1, characterized in that the drill head (18) has at least three, preferably up to seven, and particularly preferably five blades (20) extending outward from a central longitudinal axis (L) of the drill head (18).

3. 3. A masonry drill according to claim 1 or 2, characterized in that each of said blades (20) has at its outer end a projection (22) pointing away from the respective blade (20) in a direction tangential to said longitudinal axis (L).

4. 3. A masonry drill according to claim 1 or 2, characterized in that the tip of one or more of the protrusions (22) points in a direction along a circumferential direction (U) corresponding to the working rotation direction of the masonry drill (10).

5. 3. A masonry drill according to claim 1 or 2, characterized in that the blades (20) project rotationally symmetrically from the center point (M) of the drill head (18), in particular at an angle of 360° / n, where n is the number of the blades (20).

6. At least one of the blades (20), in particular two of the blades (20), is characterized in that it is retracted rearward relative to at least one adjacent one of the blades (20), i.e. in the direction of the shaft portion (12) parallel to the longitudinal axis (L).

3. A masonry drill according to claim 1 or 2.

7. 3. A masonry drill according to claim 1 or 2, characterized in that the free end of the at least one projection (22) is set back rearward with respect to the end of the projection (22) facing the blade.

8. 3. A masonry drill according to claim 1 or 2, characterized in that a double feed helix (14) is formed on said shaft portion (12).

9. 3. A masonry drill according to claim 1 or 2, characterized in that at least one of the blades (20) is supported by a support (34) projecting from the feed helix (14).

10. 3. A masonry drill according to claim 1 or 2, characterized in that there is a metallurgical bond zone (40) between the drill head (18) and the shaft portion (12).

11. 3. Masonry drill according to claim 1 or 2, characterized in that the drill head (18) has a maximum diameter of 32 mm.

12. 3. A masonry drill according to claim 1 or 2, characterized in that the drill head (18) has a diameter of at least 10 mm.

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