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 for a percussive displacement ground drilling device with a first 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 a longitudinal direction, wherein the second drilling head section includes a plurality of step-shaped areas, wherein the step-shaped areas are configured without cutting edges in a circumferential direction and/or in a radial direction, wherein each of the step-shaped areas have a step height, wherein the step height is an increase in a radius of the second drilling head section provided by the step, and wherein each step height is between about 4% and 15% of a diameter of a housing of the ground drilling device, wherein the first drilling head section is arranged in front of the second drilling head section in an advancing or forward direction; of the ground drilling device, wherein the plurality of step-shaped areas are located behind the discharge ducts of the first drilling head section, such that the plurality of step-shaped areas engage drill cuttings diverted through the discharge ducts, wherein the engaged drill cuttings are deflected and pressed into a wall of a borehole.

2. Drilling head according to claim 1, wherein said plurality of step-shaped areas is two.

3. Drilling head according to claim 2, wherein the step-shaped areas have a step height that is essentially the same.

4. Drilling head according to claim 1, wherein the ground drilling device comprises a housing and at least one of the plurality of step-shaped areas has a step length with a magnitude of at least 5% of a diameter of the housing of the ground drilling device.

5. Drilling head according to claim 1, wherein at least one of said plurality of step-shaped areas, farthest from an exposed end of the drilling head, protrudes beyond a diameter of a subsequent section of a drill string of the drilling device.

6. Drilling head according to claim 1, wherein two projections delimit each discharge duct, and wherein at least one of the projections delimiting a discharge duct protrudes beyond a diameter of the second drilling head section and/or a subsequent section of the drill string.

7. Drilling head according to claim 6, wherein two projections delimit each discharge duct, and wherein at least four projections are provided, which form four discharge ducts.

8. Drilling head according to claim 1, wherein the step-shaped areas have a step height less than a third of a width of a discharge duct.

9. Drilling head according to claim 6, wherein two projections delimit each discharge duct, and wherein at least six projections are provided, which form six discharge ducts.

10. Drilling head according to claim 1, wherein two projections delimit each discharge duct, and wherein at least one of the projections delimiting a discharge duct protrudes beyond a diameter of the second drilling head section.

11. Drilling head according to claim 1, wherein two projections delimit each discharge duct, and wherein at least one of the projections delimiting a discharge duct protrudes beyond a diameter of a subsequent section of the drill string.

12. Drilling head according to claim 1, wherein exactly two drill head sections are provided and the first drilling head section is a crown head section and the second drilling head section is a stepped head section.

13. Drilling head according to claim 1, wherein the drilling head comprises a drilling head tip and in each of the step-shaped areas at least two areas exist, which, starting from the drilling head tip, have different diameters such that a diameter adjacent to the drilling head tip is smaller than a diameter farther from the drilling head tip.

Description

BRIEF DESCRIPTIONS OF DRAWINGS

(1) The invention is clarified below by way of example with reference to the exemplary embodiments shown in the figures.

(2) The Drawings Show:

(3) FIG. 1 illustrates 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;

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

(5) FIG. 5 illustrates a further embodiment of a front section of a drilling head shown in a longitudinal section and in a front view.

DETAILED DESCRIPTION

(6) 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.

(7) 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.

(8) 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.

(9) 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.

(10) 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.