Drilling bucket and method for drilling a bore hole

Abstract

A drilling bucket for drilling a bore hole in the ground including a hollow cylindrical body and at least one cutting tool arranged at a lower side of the hollow cylindrical body for cutting soil material. The hollow cylindrical body has a lower opening for receiving soil material cut by the at least one cutting tool. For guiding the hollow cylindrical body in the bore hole an upper guiding device is provided which is arranged above the hollow cylindrical body and fixed to the hollow cylindrical body. The upper guiding device is configured to abut on a side wall of the bore hole.

Claims

1. A drilling bucket for discontinuously drilling a bore hole in the ground comprising a hollow cylindrical body, at least one cutting tool arranged at a lower side of the hollow cylindrical body for cutting soil material, the hollow cylindrical body having a lower opening for receiving soil material cut by the at least one cutting tool, and an upper guiding device for guiding the hollow cylindrical body in the bore hole, the upper guiding device being arranged above the hollow cylindrical body and fixed to the hollow cylindrical body and being configured to abut on a side wall of the bore hole, a lower guiding device arranged around an outer circumference of the hollow cylindrical body for abutment against the side wall of the bore hole, and the upper and lower guiding devices each have a diameter which is larger than a diameter of the hollow cylindrical body, wherein the hollow cylindrical body for discontinuously drilling the bore hole in the ground is configured to be filled with soil material, lifted above the ground, evacuated and then again placed in the bore hole for further excavation of soil material, wherein at least one of the upper guiding device and the lower guiding device is ring-shaped, and wherein at least one of the upper guiding device and the lower guiding device comprises a continuous arcuate outer surface having a continuous diameter.

2. The drilling bucket according to claim 1, wherein at least one of the upper guiding device and the lower guiding device includes a guide ring for abutment on the side wall of the bore hole.

3. The drilling bucket according to claim 1, wherein at least one of the upper guiding device and the lower guiding device is supported by at least one support plate extending substantially perpendicular to a cross-section of the bore hole.

4. The drilling bucket according to claim 1, wherein a coupling device is arranged centrally with regard to a cross-section of the bore hole for connecting a Kelly-bar.

5. The drilling bucket according to claim 1, wherein the upper guiding device has an arcuate outer surface for contacting the side wall of the bore hole.

6. The drilling bucket according to claim 1, wherein the hollow cylindrical body for containing cut soil material has a diameter and an axial height, wherein the diameter is greater than the axial height.

7. The drilling bucket according to claim 1, wherein a ratio of a diameter of the hollow cylindrical body to an axial height of the hollow cylindrical body is at least 1:1.

8. The drilling bucket according to claim 7, wherein the ratio of the diameter of the hollow cylindrical body to the axial height of the hollow cylindrical body is between 1:1 and 5:1.

9. The drilling bucket according to claim 1, wherein the upper guiding device is axially displaced from the hollow cylindrical body.

10. The drilling bucket according to claim 1, wherein the upper guiding device is detachably connected to the hollow cylindrical body.

11. The drilling bucket according to claim 1, wherein a plurality of cutting elements is disposed at the lower side of the hollow cylindrical body, wherein upon rotation of the drilling bucket soil material is removed along substantially the entire cross-section of the hollow cylindrical body.

12. The drilling bucket according to claim 1, wherein the lower guiding device includes a guide ring.

13. The drilling bucket according to claim 1, wherein the lower guiding device is configured to leave a substantially ring-shaped passageway around the hollow cylindrical body for a fluid bypass around the circumference of the hollow cylindrical body.

14. The drilling bucket according to claim 1, wherein the cutting tool extends in a radial direction beyond an outer periphery of the hollow cylindrical body.

15. The drilling bucket according to claim 1, wherein a soil conveying element is arranged below the hollow cylindrical body for conveying soil material radially inwardly into the hollow cylindrical body.

16. The drilling bucket according to claim 1, wherein a soil displacement element is provided for displacing soil material into the side wall of the bore hole.

17. A discontinuous drilling machine comprising a mast, a drill rod, a rotary drive for rotationally driving the drill rod, a drilling bucket including a hollow cylindrical body, at least one cutting tool arranged at a lower side of the hollow cylindrical body for cutting soil material, the hollow cylindrical body having a lower opening for receiving soil material cut by the at least one cutting tool, and an upper guiding device for guiding the hollow cylindrical body in the bore hole, the upper guiding device being arranged above the hollow cylindrical body and fixed to the hollow cylindrical body and being configured to abut on a side wall of the bore hole, a lower guiding device arranged around an outer circumference of the hollow cylindrical body for abutment against the side wall of the bore hole, and the upper and lower guiding devices each have a diameter which is larger than a diameter of the hollow cylindrical body, said drilling bucket being connected to a lower end of the drill rod, wherein the hollow cylindrical body for the discontinuous drilling machine is configured to be filled with soil material, lifted above the ground, evacuated and then again placed in the bore hole for further excavation of soil material, wherein at least one of the upper guiding device and the lower guiding device is ring-shaped, and wherein at least one of the upper guiding device and the lower guiding device comprises a continuous arcuate outer surface having a continuous diameter.

18. A method for discontinuously drilling a bore hole in the ground, said method comprising the steps of rotating a drilling bucket having a hollow cylindrical body and at least one cutting tool arranged at a lower side of the hollow cylindrical body, filling the hollow cylindrical body with soil material cut by the at least one cutting tool, abutting an upper guiding device arranged above the hollow cylindrical body on a side wall of the bore hole and guiding the hollow cylindrical body within the bore hole during drilling of the bore hole, and arranging a lower guiding device around an outer circumference of the hollow cylindrical body, wherein the upper and lower guiding devices each have a diameter which is larger than a diameter of the hollow cylindrical body, wherein the hollow cylindrical body for discontinuously drilling the bore hole in the ground is filled with soil material, lifted above the ground, evacuated and then again placed in the bore hole for further excavation of soil material, wherein at least one of the upper guiding device and the lower guiding device is ring-shaped, and wherein at least one of the upper guiding device and the lower guiding device comprises a continuous arcuate outer surface having a continuous diameter.

Description

(1) The invention will be further described with reference to the attached schematic drawings, in which:

(2) FIG. 1 shows a side view of a drilling bucket according to the invention;

(3) FIG. 2 shows a perspective view of the drilling bucket according to FIG. 1;

(4) FIG. 3 shows a side view of a drilling bucket according to the invention showing further details of the drilling bucket; and

(5) FIG. 4 shows a top view of a drilling bucket according to the invention.

(6) In all figures, the same or corresponding elements are denoted with the same reference signs.

(7) FIGS. 1 and 2 show a first embodiment of an inventive drilling bucket 10. The drilling bucket 10 includes a hollow cylindrical body 20 for containing soil material therein. A diameter of the hollow cylindrical body 20 is larger than an axial height of the hollow cylindrical body 20. The drilling bucket 10 is particularly suitable for drilling large-diameter holes having diameters preferably larger than three meters in diameter. The height of the bucket 10 can for example be up to two meters.

(8) For stabilizing the drilling bucket 10 in the bore hole, i.e. to prevent a tilting of the drilling bucket 10 within the bore hole, the drilling bucket 10 has above the hollow cylindrical body 20 an upper guiding device 60 which is configured to contact a side wall of the bore hole. According to the shown embodiment the upper guiding device 60 is configured as a guide ring 62 being arranged in a coaxial manner relative to the cylindrical body 20. The guide ring 62 has an arcuate outer surface 64 for contacting the side wall of the bore hole. The arcuate outer surface 64 has an upper tapered portion 66, a lower tapered portion 68 and a cylindrical portion 67 extending between the upper and lower tapered portions 66, 68. The tapered portions 66, 68 provide a reduced friction to the bore hole and can serve as displacement means for displacing soil material into the wall of the bore hole

(9) The guiding device 60 is fixed to the hollow cylindrical body 20 by means of support plates 70 which each extend in a plane that is perpendicular to a cross-section of the bore hole. The support plates 70 are arranged within the guide ring 62 and are connected to the guide ring 62 at an inner surface thereof. The guiding device 60 or guide ring 62 is held remotely from the hollow cylindrical body 20 by means of the support plates 70.

(10) For producing the bore hole, i.e. for cutting soil material at the bottom of the bore hole, the drilling bucket 10 comprises a cutting tool 40 arranged below the hollow cylindrical body 20. The cutting tool 40 comprises a plurality of cutting teeth 44 which are arranged along a line extending substantially along a diameter of the bore hole to be cut. In other words, the cutting teeth 44 are arranged in a radial direction between a center of the bore hole and an outer circumference of the bore hole. For supporting the cutting teeth 44 a cutting teeth support bar 42 is provided.

(11) A centering tool 50 is provided at a lower central point of the drilling bucket 10. The centering tool 50, which can also be referred to as a pilot or pilot tool, protrudes with regard to the cutting teeth 44 in an axial direction of the drilling bucket 10.

(12) A lower guiding device 80 is arranged around the hollow cylindrical body 20 for abutment against the side wall of the bore hole. The lower guiding device 80 keeps the hollow cylindrical body 20 displaced from the wall of the bore hole, so that the hollow cylindrical body 20 does not contact the bore hole. The axial height of the guiding device 80 is lower than the axial height of the hollow cylindrical body 20.

(13) In order to provide an efficient fluid bypass around the circumference of the hollow cylindrical body 20 during lowering and lifting the drilling bucket 10 within the bore hole, the lower guiding device 80 is arranged around the hollow cylindrical body 20, providing a substantially ring-shaped bypass area between the hollow cylindrical body 20 and the lower guiding device 80. The lower guiding device 80 is formed as a guide ring 82 which is attached to the hollow cylindrical body 20 by means of a plurality of support plates 90. The support plates 90 extend substantially transversely to a cross-section of the bore hole in a regular pattern around the circumference of the hollow cylindrical body 20. In the embodiment according to FIGS. 1 and 2, eight support plates 90 are provided.

(14) The lower guide ring 82 is shaped in a corresponding manner as the upper guide ring 62. In particular, the lower guide ring 82 also has an arcuate outer surface 84. The curvature of the outer surface 84 of the guide ring 82 extends in an axial direction of the drilling bucket 10. The arcuate outer surface 84 has an upper tapered portion 86, a lower tapered portion 88 and a cylindrical portion 87 extending between the upper and lower tapered portions 86, 88. The tapered portions 86, 88 provide a reduced friction to the bore hole and can serve as displacement means for displacing soil material into the wall of the bore hole.

(15) The cutting tool 40 comprising the cutting teeth 44 extends in a radial direction beyond the outer circumference of the hollow cylindrical body 20 for cutting soil material below the bypass area and/or below the lower guide ring 82.

(16) According to the invention there are generally two options for the processing of soil being cut radially outside the hollow cylindrical body 20: A first option is to guide the soil material in a radial direction in the hollow cylindrical body. A second option is to displace the soil material radially to the outside into the wall of the bore hole. Both measures can be combined.

(17) The drilling bucket 10 includes a soil displacement element 92 for displacing soil cut by a cutting tooth 44 arranged radially outside the hollow cylindrical body 20 into a side wall of the bore hole. The soil displacement element 92 has an arcuate outer surface whose curvature extends in a circumferential direction of the drilling bucket 10. The soil displacement element 92 is configured to contact the side wall of the bore hole, similar to the upper guiding device 60 and the lower guiding device 80. Therefore, the upper guiding device 60, the lower guiding device 80 and the soil displacement element 92 provide equal diameters of the drilling bucket 10 at their respective contacting faces for contacting the bore hole.

(18) In a central portion of the drilling bucket 10 a connection element or coupling device 28 for connecting a drilling rod is arranged. The coupling device 28 can in particular be a so-called Kelly-box into which a Kelly-bar can be inserted. The coupling device 28 is directly connected to the hollow cylindrical body 20 for transferring a torque applied by the drill rod to the hollow cylindrical body 20. In other words, the torque is not transferred to the hollow cylindrical body via the upper guiding device 60. The coupling device 28 for connecting a drill rod is arranged below the upper guiding device 60.

(19) The embodiment shown in FIGS. 3 and 4 differs from the previous embodiment according to the FIGS. 1 and 2 in that the support plates 70 for supporting the upper guide ring 62 are arranged in a star-shaped manner around a central axis of the drilling bucket 10, whereas according to FIGS. 1 and 2 two pairs of support plates 70 are arranged in a parallel manner.

(20) In addition, a soil conveying element 96 is provided for conveying soil material radially inwardly towards the lower opening 22 of the hollow cylindrical body 20. The soil conveying element 96 extends in a radial direction beyond the hollow cylindrical body and is preferably arranged at least in part axially above the outer cutting teeth 44. It has a guide surface for guiding the soil material cut by the outer cutting teeth 44 radially inwardly into the hollow cylindrical body 20.