Brickstone drill bit with five blade parts

Abstract

The invention relates to a masonry drill bit (10) comprising a shaft section (12) on which is formed at one end a shank section (16) for connection to a tool fitting of a power drill and at the other end a drill bit head (18) for working on a substrate. The drill head (18) has at least one blade (20) which, at the outer end thereof, has a projection (22) which points tangentially to the longitudinal axis (L) in a direction away from the blade (20). The masonry bit (10) has a high removal capability and a low risk of jamming.

Description

Technical Field

[0001] The present invention starts from a masonry drill bit, which includes a shaft section, on one end of which a shank section for connecting to a tool fitting of a power drill is formed, and on the other end a drill head for working on a substrate is formed, wherein the drill head has at least one cutting edge extending outward from the central longitudinal axis of the drill head. Background Art

[0002] This type of masonry drill bit is generally used for working on masonry (such as reinforced concrete), for example, for drilling holes in masonry.

[0003] During this process, the masonry drill bit may get stuck in the masonry. This situation especially often occurs when the masonry drill bit comes into contact with the reinforcement of the reinforced masonry.

[0004] This may cause damage to the power tool equipped with the masonry drill bit and / or injury to the user of the power tool or the masonry drill bit. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a masonry drill bit that allows for particularly safe working on masonry. It is also desirable that the masonry drill bit allows for a high drilling rate.

[0006] This object is achieved by a masonry drill bit, which includes a shaft section, on one end of which a shank section for connecting to a tool fitting of a power drill is formed, and on the other end a drill head for working on a substrate is formed, wherein the drill head has at least one cutting edge extending outward from the central longitudinal axis of the drill head, wherein the cutting edge has a protrusion at its outer end, and the protrusion points away from the cutting edge tangentially to the longitudinal axis.

[0007] This is based on the following consideration: The masonry drill bit gets stuck in the reinforced masonry, especially when the reinforcement may be jammed between the cutting edges of the drill head. Therefore, it is advantageous to fill as much as possible the large intermediate space volume between the cutting edges, or to keep the intermediate space as small as possible in general.

[0008] In particular, the size of the intermediate space can be reduced by the protrusion or protrusions. At the same time, the protrusion or protrusions may not affect the effective contact area, and thus may not affect the specific impact force and the resulting removal ability.

[0009] A higher number of cutting edges enables the masonry drill bit to be guided in a more stable manner during the drilling process. The risk of the reinforcement being jammed between the cutting edges formed closer together can be further reduced.

[0010] Thus, it may be advantageous in principle to provide a plurality of cutting edges on the drill head. However, an increase in the number of cutting edges is also associated with an increase in the contact area between the drill head and the substrate (that is, for example, reinforced masonry). For a power tool equipped with such a masonry drill, with the same impact energy and impact frequency for each impact, the specific impact force related to the contact area will thus decrease. Therefore, the removal ability of the masonry drill may decrease with an increase in the number of cutting edges.

[0011] Based on previous experience, it has been found that an advantageous balance, particularly a balance between the tendency to jam, stability, and removal ability, is obtained if the drill head has at least three, preferably at most seven, and particularly preferably five cutting edges extending radially outwards from the central longitudinal axis of the drill head.

[0012] Each of the cutting edges may have a protrusion at its outer end, which protrusion points tangentially away from the respective cutting edge with respect to the longitudinal axis, thus enabling the intermediate space between adjacent cutting edges to be further reduced in size.

[0013] Therefore, the masonry drill allows drilling work without any risk of jamming, or at most with a minimal risk and thus particularly safe operation.

[0014] Further features and advantages of the present invention emerge from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings and from the claims, which show the essential details of the present invention. The features shown therein are not necessarily to be considered in true scale, but are presented in a way that enables the special features according to the present invention to be clearly visualized. In variants of the present invention, the various features may be implemented individually by themselves or in any combination. Description of the Drawings

[0015] Exemplary embodiments of the present invention are shown in schematic diagrams and are explained in detail in the following description. In particular, the features described in the dependent claims are also elucidated with reference to the drawings.

[0016] In the drawings:

[0017] Figure 1 The masonry drill is shown in a side view,

[0018] Figure 2 A perspective view of the masonry drill is shown,

[0019] Figure 3 Another perspective view of the masonry drill is shown,

[0020] Figure 4 A plan view of the drill head of the masonry drill is shown,

[0021] Figure 5 A perspective view showing a masonry drill bit and more particularly the front section of the drill bit head

[0022] Figures 6 to 9 A plurality of side views showing the shaft section of the masonry drill bit and a partial section of the drill bit head adjacent to the shaft section, and

[0023] Figure 10 Showing corresponding to the masonry drill bit Figure 6 The side view of the view shown in Detailed Description

[0024] In the following description of the drawings, understanding of the present invention is facilitated by using the same reference numerals for the same or functionally corresponding elements in each case.

[0025] Figure 1 The masonry drill bit 10 is shown in a side view. The masonry drill bit 10 includes a shaft section 12. A delivery helix 14 is formed on the shaft section 12.

[0026] A shank section 16 for connecting to a tool fitting of a power drill ( Figure 1 not shown in the figure) is formed at one end of the shaft section 12, and a drill bit head 18 for working on a substrate ( Figure 1 not shown in the figure), such as reinforced masonry, is formed at the other end.

[0027] For example, the shank section 16 is in the form of a shank commonly referred to as "SDS Max". It is also conceivable that the shank is in the form of an "SDS Plus" or a similar standardized shank.

[0028] The delivery helix 14 is designed as a double - line helix. As an alternative, it is also conceivable to design the delivery helix as a triple - line helix, a quadruple - line helix or a quintuple - line helix. The double - line helix can convey the removed masonry from the drill bit head 18 at a high delivery rate. It can have a relatively robust design and can still be suitable for production at an acceptable cost. The pitch of the helix is far enough so as to ensure that even relatively large removed masonry particles can be conveyed along the delivery helix without jamming. Therefore, the delivery helix 14 designed as a double - line helix has proven to be particularly advantageous.

[0029] The drill bit head 18 has five cutting edges 20. For clarity, only one cutting edge 20 is indicated by the reference numeral.

[0030] The cutting edges 20 extend outwardly from the central longitudinal axis L of the drill bit head 18. It should be understood that the masonry drill bit 10 can also operate in an impact mode, particularly along the longitudinal axis L, in order to remove masonry. In summary, therefore, the masonry drill bit 10 can be operated in a rotary - impact mode to remove masonry.

[0031] The masonry drill bit 10 can be designed for drilling holes with a diameter of at least 10 mm and / or at most 32 mm, so that despite the special geometry described in detail below, sufficient material thickness can still be ensured at all points.

[0032] Furthermore, with such dimensions, the weight and thus the associated inertia can be kept within a range suitable for removing masonry by rotary percussion.

[0033] The drill head 18 preferably comprises a material that is more fracture-resistant than the shank section 12. For example, the shank section 12 can comprise steel, while the drill head can comprise hard metal, such as tungsten-based hard metal.

[0034] Figure 2 and Figure 3 Fig. shows another perspective view of the masonry drill bit 10, in particular enabling the delivery helix 14, the shank section 16 and the drill head 18 to be seen from more viewing directions.

[0035] Figure 4 Fig. shows a plan view of the drill head 18. Five cutting edges 20 can be seen.

[0036] At its outer end, each of the cutting edges 20 has a projection 22 that points away from the respective cutting edge 20 tangentially to the longitudinal axis L. Here again, for the sake of clarity, only one of the projections 22 is indicated by reference numerals.

[0037] For example, it can be seen from Figure 4 that the projections 22 that point away from the respective cutting edges 20 tangentially to the longitudinal axis L each have at least one main direction H that has at least one main direction component in the tangential direction.

[0038] The projection 22 points in the circumferential direction U. The circumferential direction U corresponds to the rotational working direction of the masonry drill bit 10, in which the masonry drill bit rotates to remove the substrate. Thus, during the masonry removal process, the projection 22 always moves slightly ahead of its associated cutting edge 20.

[0039] As an alternative or additionally, it can also be envisaged that at least one of the projections 22 points in the direction opposite to the circumferential direction, that is to say, thus lagging slightly behind its associated cutting edge 20 in each case.

[0040] In particular, in the case of an alternative masonry drill bit, at least one of the cutting edges 20 can be provided with a leading projection and a trailing projection 22.

[0041] By means of the projection 22, the intermediate space 24 between the respective adjacent cutting edges 20 (inFigure 4 The size (only one of which is indicated by reference numerals in the figure by way of example) is reduced as well.

[0042] At the same time, a free space is reserved in the intermediate space 24, so that the comminuted material can reach the conveying screw 14 from the free space.

[0043] The cutting edge 20 extends from the center point M of the drill head 18, i.e., transversely to the longitudinal axis L, in a rotationally symmetric manner, preferably at an angle α between 70° and 80°, specifically 72° (see Figure 1 ). The rotationally symmetric arrangement results in a particularly uniform distribution of the contact between the drill head 18 and the substrate over the cross-section of the drill head 18. As a result, the masonry drill 10 can be introduced into the substrate to be drilled in a very stable manner.

[0044] The cutting edge 20 has cutting edges 26. In addition to one cutting edge 26, that is, Figure 4 in, in addition to the cutting edge 26 at about 1 o'clock (i.e., the cutting edge extending obliquely upwards to the right), the remaining cutting edges 26 are curved.

[0045] It is also conceivable to form an alternative masonry drill 10 which has such cutting edges 26 but no protrusion 22. Such an alternative masonry drill 10 can have one or more of the features described above and / or below and / or features included in the figures, in particular except for the features related to the protrusion 22.

[0046] Figure 5 Another perspective view of the masonry drill 10 is shown. Specifically, one end of the masonry drill 10 with its drill head 18 can be seen.

[0047] Two of the five cutting edges 20, specifically their free ends, are set back relative to the respective adjacent cutting edges 20, i.e., parallel to the longitudinal axis L in the direction of the conveying screw 14. They form secondary cutting edges 28. Thus, the drill head 18 mainly impacts the substrate to be drilled with the remaining three cutting edges 20 (hereinafter referred to as main cutting edges 30).

[0048] The curvature of the secondary cutting edges 28 perpendicular to the longitudinal axis L is greater than that of the main cutting edges 30, thereby further improving the removal of drilling dust.

[0049] This gives the masonry drill 10 with five cutting edges 20 a particularly high specific impact force and thus a particularly high removal capacity.

[0050] In addition to its stabilizing function already described above, the secondary cutting edge 28 can be used particularly when the masonry drill bit 10 strikes a reinforcement (e.g., a steel reinforcement) and may penetrate into the reinforcement by a certain distance. Then, the secondary cutting edge 28 can accelerate the removal of the reinforcement.

[0051] Furthermore, it can be seen from Figure 5 that the free end of the protrusion 22 is set back relative to its end facing the cutting edge (i.e., towards the conveying helix 14), and thus, during the normal removal of masonry, the protrusion 22 also does not strike the substrate, thereby additionally minimizing the effective contact area in favor of a high specific impact force. The protrusion 22 also forms a sliding surface together with the side surface of the cutting edge 20, along which the crushed material can be guided to the conveying helix 14, and thus the backward offset of the free end of the protrusion 22 also improves the removal of the crushed material.

[0052] Furthermore, it can be seen from Figure 5 and also in combination with Figures 1 to 3 that the conveying helix 14 has a double - thread design in order to achieve a high conveying capacity.

[0053] The cutting edge 20 that is not directly adjacent to the helix wall 33 is supported by a support 34 protruding from the conveying helix 14. Also, for the sake of clarity, in Figure 5 only one helix wall 33 of one of the helix grooves 32 of the conveying helix 14 is indicated by the reference numeral. The support 34 is formed independently of the helix wall 33 in such a way that it protrudes from the conveying helix 14. Thus, one such support 34 is formed for the five cutting edges 20 and the double - thread conveying helix 14.

[0054] The support 34 thus enables the connection of the drill head 18 to the plurality of cutting edges 20 by means of the conveying helix 14, which has a different number of helix walls 33 from the number of cutting edges 20. In particular, the drill head 18 can be provided with an odd number of cutting edges 20 and a conveying helix 14 with an even number of grooves. Thus, a particularly favorable configuration of the corresponding drill head 18 can be combined with a particularly favorable configuration of the conveying helix 14.

[0055] All the cutting edges 20 open into the conveying helix 14 along the wall 36. For the sake of clarity, in Figure 5 also only one wall 36 is provided with a reference numeral. The wall 36 extends parallel to the longitudinal direction L, and thus the introduction region 38 (where again only one is provided with a reference numeral) is obtained parallel to the longitudinal direction L and this introduction region opens into the conveying helix 14. The introduction region 38 and in particular the wall 36 extending parallel to the longitudinal direction L are used to further improve the removal of the crushed material.

[0056] The drill head 18 can preferably be butt - joined to the shaft section 12 by means of a metallurgical joint zone 40 in order to ensure the necessary strength of the connection. The metallurgical joint zone 40 can be produced, for example, by welding or soldering.

[0057] Figures 6 to 9 A plurality of side views of the shaft section 12 of the masonry drill 10 and partial sections of the drill head 18 adjacent to this shaft section are shown from different perspectives.

[0058] It can be seen in particular from Figure 6 that the cutting edge 20 with the reference numeral is located on the support 34. The support 34 is in turn designed to project from the conveying helix 14. It is located between the two helical walls 33 of one of the helical grooves 32.

[0059] This support of the cutting edge 20 by the support 34 can be provided both for a cutting edge 20 with a tangential projection and for a cutting edge 20 without a tangential projection. By way of example, Figures 6 to 9 shows a cutting edge 20 without a tangential projection.

[0060] In the view corresponding to Figure 6 Figure 10 a partial section of the masonry drill 10 is shown, on which the cutting edge 20 has a tangential projection 22, where again only one cutting edge 20 and the associated projection 22 are indicated by the reference numerals.

[0061] List of reference numerals

[0062] 10 Masonry drill

[0063] 12 Shaft section

[0064] 14 Conveying helix

[0065] 16 Shank section

[0066] 18 Drill head

[0067] 20 Cutting edge

[0068] 22 Projection

[0069] 24 Intermediate space

[0070] 26 Cutting edge

[0071] 28 Secondary cutting edge

[0072] 30 Main cutting edge

[0073] 32 Helical groove

[0074] 33 Helical wall

[0075] 34 Support

[0076] 36 walls

[0077] 38 introduction area

[0078] 40 metallurgical bonding area

[0079] H main direction

[0080] L longitudinal axis

[0081] M center point

[0082] U circumferential direction

[0083] α angle

Claims

1. A masonry drill bit (10) comprising a shaft section (12) having at one end formed thereon a shank section (16) for connection to a tool fitting of a power drill and at the other end formed thereon a drill head (18) for working on a substrate, wherein, The drill head (18) has at least one cutting edge (20) extending outward from the central longitudinal axis (L) of the drill head (18). It is characterized in that the cutting edge (20) has a protrusion (22) at its outer end, and the protrusion points away from the cutting edge (20) tangentially to the longitudinal axis (L).

2. The masonry drill bit according to the previous claim, characterized in that, The drill head (18) has at least three, preferably at most seven, particularly preferably five cutting edges (20) extending outward from the central longitudinal axis (L) of the drill head (18).

3. The masonry drill bit according to any one of the preceding claims, characterized in that, Each of the cutting edges (20) has a protrusion (22) at its outer end, and the protrusion points away from the corresponding cutting edge (20) tangentially to the longitudinal axis (L).

4. The masonry drill bit according to any one of the preceding claims, characterized in that The protrusion (22) or the protrusions (22) point in the circumferential direction (U), and the circumferential direction corresponds to the rotational working direction of the masonry drill (10).

5. The masonry drill bit according to any one of the preceding claims, characterized in that The cutting edges (20) extend from the center point (M) of the drill head (18) in a rotationally symmetric manner, specifically at an angle of 360° / n, where n is the number of cutting edges (20).

6. The masonry drill bit according to any one of the preceding claims, characterized in that, At least one of the cutting edges (20), in particular two of the cutting edges (20), is set back relative to at least one of the adjacent cutting edges (20), that is, parallel to the longitudinal axis (L) in the direction of the shaft section (12).

7. The masonry drill bit according to any one of the preceding claims, characterized in that, The free end of the at least one protrusion (22) is set back relative to the end of the protrusion (22) facing the cutting edge.

8. The masonry drill bit according to any one of the preceding claims, characterized in that, A double - wire conveying helix (14) is formed on the shaft section (12).

9. The masonry drill bit according to any one of the preceding claims, characterized in that, At least one of the cutting edges (20) is supported by a support (34) protruding from the conveying helix (14).

10. The masonry drill bit according to any one of the preceding claims, characterized in that, There is a metallurgical bonding zone (40) between the drill head (18) and the shaft section (12).

11. The masonry drill bit according to any one of the preceding claims, characterized in that, The drill head (18) has a diameter of at most 32 mm.

12. The masonry drill bit according to any one of the preceding claims, characterized in that, The drill head (18) has a diameter of at least 10 mm.

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