Drilling head for a percussive displacement ground drilling device and use of a drilling head for a percussive displacement ground drilling device

Abstract

A drilling head for a percussive displacement ground drilling device with a first drilling head section and a second drilling head section, the first drilling head section having discharge ducts, and the second drilling head section having a cross section that increases in the longitudinal direction, wherein the second drilling head section includes a plurality of step-shaped areas.

Claims

1. Drilling head (1) for a percussive displacement ground drilling device with a first and a second drilling head section (4, 5), the first drilling head section (4) having discharge ducts (6) and the second drilling head section (5) having a cross section that increases in the longitudinal direction, characterized in that the second drilling head section (5) has several step-shaped areas (7, 8).

2. Drilling head (1) according to claim 1, characterized in that the step-shaped areas (7, 8) are designed without cutting edges in the circumferential direction and/or in the radial direction (R).

3. Drilling head (1) according to claim 1 or 2, characterized in that there are two step-shaped areas (7, 8).

4. Drilling head (1) according to claim 3, characterized in that the step-shaped areas (7, 8) have essentially the same step height (H1, H2).

5. Drilling head (1) according to one of claims 1 through 4, characterized in that between the step-shaped areas (7, 8), there is at least one step height (H1, H2) with a magnitude of at least 4% of the housing of a ground drilling device, in particular a percussion drilling device.

6. Drilling head (1) according to one of claims 1 through 5, characterized in that at least one of the step-shaped areas (7, 8) has a step length (SL1, SL2) with a magnitude of at least 5% of the housing of a ground drilling device, in particular a percussion drilling device.

7. Drilling head (1) according to one of claims 1 through 6, characterized in that the last step-shaped area (8), farthest from the exposed end of the drilling head (1), protrudes beyond the diameter of a subsequent section of the drill string.

8. Drilling head (1) according to one of claims 1 through 7, characterized in that at least one of the projections (9) delimiting a discharge duct (6) protrudes beyond the diameter of the second drilling head section (5) and/or a subsequent section of the drill string.

9. Drilling head (1) according to one of claims 1 through 8, characterized in that at least four, preferably six, projections (9) are provided, which form four or six discharge ducts (6).

10. Drilling head (1) according to one of claims 1 through 9, characterized in that the step height (H1, H2) is less than a third of the width of a discharge duct (6).

11. Use of a drilling head (1) for a percussive displacement ground drilling device with a first and a second drilling head section (4, 5), a drilling head section with discharge ducts (6) being used as the first drilling head section (4), which destroys obstacles, and a drilling head section with a cross section that increases in the longitudinal direction (L) being used as the second drilling head section (5), wherein several stepped-shaped areas (7, 8) are used for the second drilling head section (5), which can be used for rotating and/or screwing of debris of the obstacles in to the sidewall of the borehole.

Description

[0036] The drawings show:

[0037] FIG. 1 a front section of a drilling head in a longitudinal section (a) and a front view (b), in which the comminution of an obstacle is shown by way of example using debris from an obstacle;

[0038] FIG. 2 through 4 the longitudinal section (a) and the front view (b) according to FIG. 1 with the further trajectory of the debris; and

[0039] FIG. 5 a further embodiment of a front section of a drilling head shown in a longitudinal section and in a front view.

[0040] FIG. 1 shows, in a longitudinal section (a) and in a front view (b), a front section of a drilling head 1 for a percussive displacement ground drilling device. The drilling head 1 has a housing 2 in which a drilling head tip 3 in the form of a drill bit is located. In the front area of the drilling head 1, a first and a second drilling head section 4, 5 are arranged around the drilling head tip 3. The drilling head sections 4, 5 are formed in one piece as an attachment on the drilling head 1. The first drilling head section 4 has discharge ducts 6. The second drilling head section 5 has a cross section that increases in the longitudinal direction L. The second drilling head section 5 also has several step-shaped areas 7, 8.

[0041] The step-shaped areas 7, 8 are designed without cutting edges in the circumferential direction and in the radial direction R. The step-shaped areas have a step height H1, H2 and a step length SL1, SL2.

[0042] FIG. 1 shows how an existing obstacle is comminuted with the first drilling head section 4 and how a fragment of the obstacle passes through one of the discharge ducts 6 in the longitudinal direction L of the drilling head 1 when the drilling head 1 moves. When the fragment reaches a step of the step-shaped areas 7, 8, the fragment is rotated according to the arrow shown in FIG. 2 and essentially screwed into the borehole wall. The screwing in or levering in of the fragment of the obstacle is shown in FIGS. 2 and 3 for each of the two steps. It is implied in FIG. 4 that the fragment of the obstacle was embedded or screwed into the borehole wall.

[0043] The embodiment shown in FIG. 5 differs essentially from the embodiments shown in FIGS. 1 through 4 in that the projections 9 of the first drilling head section 4 delimiting the discharge ducts 6 protrude beyond the circumference or diameter of the second drilling head section 5. In addition, the second drilling head section 5 protrudes beyond the circumference or the diameter of the housing 2, wherein, in an embodiment not shown, the second drilling head section 5 does not protrude beyond the circumference or the diameter of the housing 2 and therefore essentially has a circumference or diameter that is less than or equal to the housing 2.

[0044] In FIG. 5, the diameter D4 of the first drilling head section 4 formed by the projections 9 is approximately 5% larger than the diameter D5 of the second drilling head section 5. The diameter D5 of the second drilling head section 5 is approximately 5% larger than the diameter D6 of the housing 2.