Drill head, and drilling system including drill head

Abstract

To provide an improved drill head.SOLUTION: A drill head comprises: a base body which is rotatable during operation about a rotation axis and expandable in terms of its effective drilling diameter, and has an end face (4) on which a cutting tool (3) is mounted; and an opening arm (5) pivotably connected to the base body about a pivot axis. The opening arm (5) is pivotable between a retracted position and a first extended position which expands the effective drilling diameter by a first value. The opening arm (5) has an active surface (8) on which a cutting tool (7) is mounted. In the retracted position of the opening arm (5), the active surface (8) is positioned on a plane together with the end face (4) of the base body. In the first extended position of the opening arm (5), the active surface (8) extends from the end face (4) of the base body at least approximately without a step-like offset in a direction of the rotation axis.SELECTED DRAWING: Figure 2

Description

[[Technical Field]]

[0001] The present invention relates to a drill head, which is rotatable about a rotation axis during operation, and expandable with respect to its effective drilling diameter, comprising a base body having an end face on which at least one cutting tool is mounted, and at least one expansion arm pivotably connected to the base body about a pivot axis, wherein the expansion arm is pivotable between a retracted position and a first extended position where the effective drilling diameter is enlarged by a first value, and the expansion arm has a working surface on which at least one cutting tool is mounted. [[Background Art]]

[0002] A drill head having these features is known from Korean Patent Publication No. 20060006754. In the retracted position, at least one cutting tool of the expansion arm does not function, and in the extended position, during operation, diameter enlargement following the hole bottom of the hole bored by the base body is performed.

[0003] Such a drill head is used, for example, when drilling offshore foundations for wind power installations.

[0004] Against the requirement of improving the performance of wind power installations, particularly those that are part of the so-called "offshore wind farms", there is a trend that wind power installations are becoming larger and larger. Accordingly, the foundations for wind power installations must be designed to withstand ever-increasing loads.

[0005] To meet this requirement, for example, it is known that multiple piles, for instance, arranged in a triangle, can be used as a foundation for a wind turbine. These piles are bored into the seabed and protrude above the sea surface. The upper ends of these piles are connected to each other via a support structure to which the lower ends of the wind turbine towers are attached. These foundations, also called "tripods," have the disadvantage of significantly increasing construction costs, particularly due to the multiple foundation drilling required.

[0006] Therefore, today, the towers of wind turbines, which are widely used in offshore areas, are each anchored to the top of a single pile foundation (also called a "monopile"). To achieve the necessary stability of these pile foundations, they have a diameter greater than the diameter of each top to which the wind turbine tower is anchored, at least over the length that the pile foundation is inserted into the seabed in the underwater area. Thus, these pile foundations often have a "flange neck" that transitions the two regions of different diameters toward each other.

[0007] To bore these pile foundations, it is periodically necessary to drill and extract the seabed located inside the piles. This requires introducing the drill head into the pile foundation from above through a small-diameter area. Therefore, it is necessary to use the type of drill head mentioned earlier, which allows for an expandable effective drilling diameter. [Overview of the project] [Problems that the invention aims to solve]

[0008] The fundamental problem of this invention is to provide a drill head that has been improved for the use described above. [Means for solving the problem]

[0009] This problem is solved by the drill head described in claim 1.

[0010] The drill head according to the present invention is formed such that the working surface of the expansion arm, when retracted, is located together with the end face of the base body in at least substantially one plane. The phrase "at least substantially" means that there should not be a stepped displacement (Stufenversatz) between the working surface of the expansion arm and the end face of the base body that is greater than the extended length of the cutting tool in the direction of the rotation axis.

[0011] Based on this configuration, in the drill head according to the present invention, at least one cutting tool of at least one expanding arm can continue to cut the ground at the bottom of the hole even when it is retracted. As a result, the drilling power that can be obtained with the drill head according to the present invention is improved compared to a conventional drill head, that is, a drill head in which at least one cutting tool of at least one expanding arm does not function when it is retracted.

[0012] Furthermore, the drill head according to the present invention is formed such that the working surface is connected to the end face of the base body at the first extruded position of the expanding arm with at least substantially no stepped displacement in the direction of the rotation axis.

[0013] "At least without a stepwise displacement" means that it is desirable that the stepwise displacement is not greater than the extended length of the cutting tool in the direction of the rotation axis. "Without a stepwise displacement" does not mean that the working surface and the end surface must be oriented parallel to each other. Rather, the working surface may be inclined relative to the end surface.

[0014] Based on this configuration, at least one cutting tool of at least one expanding arm operates in a plane that opens at least substantially without stepwise displacement to the plane on which at least one cutting tool of the base body works, in the first extruded position. This results in a bore bottom that does not have a stepwise displacement in the horizontal direction of the enlarged diameter when boring a hole with the expanding arm in the first extruded position. However, the area of ​​the bore bottom provided by at least one expanding arm may be inclined with respect to the area provided by the base body.

[0015] In holes drilled with the type of drill head described at the beginning, the area of ​​the hole bottom drilled by the base body of the drill head precedes the area drilled by the expanding arm. However, since this area is unnecessary for drilling pile foundations, the necessary costs in the type of drill head described at the beginning are increased by avoidable drilling time and avoidable amount of material to be removed, which are avoided by the drill head according to the present invention.

[0016] In a preferred development of the drill head according to the present invention, at least one expanding arm is pivotable to a second extruded position that expands the effective drilling diameter of the drill head by a second value. Based on this configuration of the drill head, it is possible to first drill a hole through the interior of the pile foundation to the lower end of the pile foundation with an effective drilling diameter expanded by a first value, and then to further drill the hole with an effective drilling diameter expanded by a second value. This makes it significantly easier to penetrate the pile foundation to the required final depth. The effective drilling diameter expanded by a second value is therefore preferably selected such that this effective drilling diameter corresponds to at least the outer diameter of the pile foundation.

[0017] In another preferred embodiment of the drill head according to the present invention, the working surface of at least one expanding arm is inclined from the end face toward the base body at an angle of 20° to 45° with respect to the end face of the base body in a first and / or second extruded position. Based on this means, the area of ​​the hole bottom provided by at least one expanding arm rises by approximately the same angle as the area provided by the base body. Surprisingly, it has been found that in this way the loosened material can be particularly effectively removed from the hole bottom, and thus friction of the drill head during boring of the hole can be reduced. Thus, this preferred embodiment stands out in particularly low energy requirements for boring the hole and particularly low wear of the drill head, especially the cutting tool.

[0018] In another preferred embodiment of the drill head according to the present invention, a closing element is provided that at least substantially closes the relief face that occurs between the end face and the working surface at the first and / or second extruded positions of the expanding arm. This prevents cutting material from entering the area of ​​the drill head through this relief face. The cutting material could block the return movement of at least one of the expanding arms to the retracted position, which could make it difficult, or even impossible, to pull the drill head out of the hole.

[0019] In a preferred embodiment of the drill head according to the present invention, at least one expanding arm has a side facing the rotation axis of the drill head. In this side region, a first end of an operating lever is pivotally attached to the expanding arm so as to be movable about an axis extending substantially parallel to the pivot axis, and a second end of the operating lever is pivotally attached to the base body so as to be movable along a guide extending laterally to the axis. Based on this configuration, at least one expanding arm is particularly stably connected to the base body, thereby allowing the force acting on at least one expanding arm at a first or second extruded position to be introduced to the base body without damage, even when drilling holes in rock.

[0020] Preferably, a linear motor is provided, pivotally attached at a first end to the base body and at a second end to an operating lever, to move at least one expanding arm between a retracted position and a first and / or second extended position. The concept of “linear motor” should not be understood as being limited to electrically operated motors, but should be interpreted broadly. In particular, this concept of linear motor should be understood to include hydraulic cylinders or pneumatic cylinders. In a particularly preferred embodiment of the drill head according to the present invention, a hydraulic cylinder is provided, pivotally attached at a first end to the base body and at a second end to an operating lever.

[0021] In a particularly preferred development of the drill head according to the present invention, the operating lever is configured such that it forms a closing element. This avoids the structural costs associated with an additional closing element.

[0022] In an embodiment of the drill head according to the present invention that is particularly suitable for boring holes even in rocky ground, preferably, at least a portion of the cutting tool is formed as a rotating bit.

[0023] In an embodiment of the drill head according to the present invention that is particularly suitable for use in forming pile foundations for wind power installations in offshore areas, the base body of the drill head and the at least one expansion arm are configured such that the effective drilling diameter can be expanded within the range of 5000 to 8000 mm. In one embodiment of the drill head according to the present invention, for example, the effective drilling diameter may be 5150 mm when the at least one expansion arm is in the retracted position, 6800 mm when expanded by a first value in the first extended position, and 7400 mm when expanded by a second value in the second extended position.

[0024] The present invention also relates to a drill system comprising a rotary device, a support string (Tragstrang), and a drill head according to the present invention connected to the support string.

[0025] The drawings merely schematically show one embodiment of the drill head according to the present invention. Brief Description of the Drawings

[0026] [Figure 1] It is a side view showing an embodiment of the drill head according to the present invention in a small-diameter pile region, which includes the expansion arm in the retracted position. [Figure 2] It is a bottom view of this embodiment of the drill head with the expansion arm in the retracted position shown in Fig. 1. [Figure 3] It is a view corresponding to Fig. 1 showing the same embodiment of the drill head according to the present invention in a large-diameter pile region, which includes the expansion arm in the first extended position. [Figure 4] It is a view corresponding to Fig. 3 showing the same embodiment of the drill head according to the present invention at a position below the lower end of the pile, which includes the expansion arm in the second extended position. [Figure 5]This diagram shows the same embodiment of the drill head according to the present invention, viewed from below, in which the horizontally extending expansion arm is in the first pushed-out position and the vertically extending expansion arm is in the second pushed-out position. [Modes for carrying out the invention]

[0027] An embodiment of the drill head according to the present invention, shown entirely by reference numeral 100 in the figure (hereinafter simply referred to as "drill head 100"), is connected to a support system 1, schematically shown in Figure 1, during operation. This support system 1 can be rotated about a rotation axis S using a rotating device (not shown). As a result, the drill head 100 is rotatable about the rotation axis S during operation.

[0028] The drill head has a base body 2, which has an end face 4 on which multiple cutting tools 3 are attached.

[0029] Furthermore, the drill head 100 has expansion arms 5, which are positioned 90° apart from each other in the rotational direction with respect to their central plane. Each expansion arm 5 is connected to the base body 2 using a pin 6, which defines a pivot axis W, and each expansion arm is rotatable around this pivot axis W. The pivot axis W is oriented perpendicular to the rotation axis S.

[0030] Each expanding arm 5 has a working surface 8 on which multiple cutting tools 7 are mounted.

[0031] Each expanding arm 5 can be rotated about the pivot axis W between a retracted position shown in Figures 1 and 2, where the respective working surface 8 and end face 4 are located on at least approximately one plane E and the drill head has an effective drilling diameter D0 (see Figure 1); a first extruded position (see Figure 3) where the effective drilling diameter D1 is expanded by a first value B1; and a second extruded position (see Figure 4) where the effective drilling diameter D2 is expanded by a second value B2.

[0032] As can be seen in Figures 3 and 4, the working surface 8 of the expanding arm 5 extends from the end face 4 of the base body 2 with respect to the direction of the rotation axis S, but only at the first extruded position (Figure 3) and the second extruded position (Figure 4).

[0033] When the expanding arm 5 is in the first and second extruded positions, the working surface 8 has an angle α of 20° to 45°, preferably about 37°, with respect to the end face 4 of the base body 2. In this way, the material removed by the cutting tool 7 of the expanding arm 5 can reach the center of the hole under the action of gravity and can be discharged relatively easily, for example by suction, through the suction opening 9 located on the end face 4 of the base body 2.

[0034] A hydraulic cylinder 10 is provided for each of the expansion arms 5 so that it can be rotated between the retracted position and the first and second extended positions. Each hydraulic cylinder is pivotally attached to the base body 2 at the first end 11 and to the operating lever 13 at the second end 12.

[0035] Each operating lever 13 is attached at its first end 14 to a lateral region of the expanding arm 5 facing the axis of rotation S. The second end 15 of the operating lever 13 is supported by the base body 2 so as to be movable parallel to the axis of rotation S within a guide 16.

[0036] As can be seen by comparing Figures 1, 3, and 4, the change in the length of the hydraulic cylinder, in this configuration, causes the expanding arm 5 to rotate around the pivot axis W.

[0037] The operating levers 13 are formed such that they at least substantially close the relief surfaces that occur at the first and second extruded positions between the end face 4 of the base body 2 and the working surface 8 of the expansion arm 5. In this way, the operating levers 13 simultaneously function to form a closing element 17 that prevents cutting material from entering the base body 2 and, if possible, the resulting blocking of the expansion arm 5. [Explanation of Symbols]

[0038] 100 Drill Heads 1 Support system 2 Base Body 3 cutting tools 4 End face 5. Expanding Arm 6 pins 7 Cutting tools 8 Working surface 9. Inlet opening 10 Hydraulic cylinder 11 First end 12 Second end 13. Operating lever 14 First end 15. Second end 16 Guide 17 Closure elements B1, B2 values D0,D1,D2 diameter E plane S rotation axis W pivot axis α angle

Claims

1. A drill head (100) is rotatable about a rotation axis (S) during operation, and has an effective drilling diameter (D ０ , D １ , D ２ ) is expandable in relation to, A base body (2) having an end face (4) to which at least one cutting tool (3) is attached, The system includes at least one expanding arm (5) connected to the base body (2) so as to be rotatable about a pivot axis (W) which is perpendicular to the rotation axis (S), wherein the expanding arm (5) has a retracted position and the effective drilling diameter is set to a first value (B １ It is pivotable between the first extruded position, which expands by only that much, The at least one expanding arm (5) has an operating surface (8) on which at least one cutting tool (7) is attached, The working surface (8), in the retracted position of the at least one expanding arm (5), is located together with the end face (4) of the base body (2) in at least one substantially plane (E), The working surface (8) extends from the end face (4) of the base body (2) at least with substantially no stepped displacement in the direction of the rotation axis (S) at the first extruded position of the at least one expanding arm (5), The at least one expansion arm (5) has a second value (B) with respect to the effective drilling diameter. ２ It is rotatable to a second, extruded position, which is only enlarged by that amount. The working surface (8) extends from the end face (4) of the base body (2) at least with substantially no stepped displacement in the direction of the rotation axis (S) at the second extruded position of the at least one expanding arm (5), The second value (B2) is greater than the first value (B1). Drill head (100).

2. The drill head (100) according to claim 1, wherein the working surface (8) of at least one expanding arm (5) is tilted at an angle (α) of 20° to 45° with respect to the end face (4) of the base body (2) toward the base body (2) at the first extruded position and / or the second extruded position.

3. A closing element (17) is provided between the end face (4) and the working surface (8) to at least substantially close the relief surface that occurs at the first or second extruded position of the at least one expanding arm (5).

4. The drill head (100) according to claim 3, wherein the at least one expanding arm (5) has a side surface oriented toward the axis of rotation (S), and in the region of this side surface, the first end (14) of the operating lever (13) is pivotally attached to the at least one expanding arm (5) so as to be rotatable about an axis extending substantially parallel to the axis of rotation, and the second end (15) of the operating lever (13) is pivotally attached to the base body (2) so as to be movable along the guide (16).

5. The drill head (100) according to claim 4, wherein a linear motor is provided, pivotally attached to the base body (2) at a first end (11) and to the operating lever (13) at a second end (12), and the linear motor preferably has a pneumatic cylinder, and more preferably a hydraulic cylinder (10).

6. The drill head (100) according to claim 4 or 5, wherein the operating lever (13) is sized to form the closing element (17).

7. A drill head (100) according to any one of claims 1 to 6, wherein at least a portion of the cutting tool (3, 7) is formed as a rotating bit.

8. The drill head (100) according to any one of claims 1 to 7, wherein the effective drilling diameter can be expanded from 5,000 to 8,000 mm.

9. A drill system including a rotating device and a support system (1), The drill system further includes a drill head (100) according to any one of claims 1 to 8, wherein the drill head (100) is connected to the support system (1).

10. A method for using a drill head (100) according to any one of claims 1 to 8, wherein the method is: The drill head (100) is introduced through the top of the pile foundation using the support system (1), and at this time, the at least one expanding arm (5) is in the retracted position. The at least one expanding arm (5) is expanded to the first extruded position, At the first extruded position, the drill head (100) is used to excavate inside the pile foundation. The at least one expanding arm (5) is expanded to the second extruded position, At the second extruded position, the drill head (100) is used to excavate below the pile foundation. A method that includes the act of doing so.

11. Use of the drill head (100) according to any one of claims 1 to 8, The drill head (100) is introduced through the top of the pile foundation using the support system (1), and at this time the at least one expanding arm (5) is in the retracted position. The at least one expanding arm (5) is expanded to the first extruded position, Using the drill head (100) at the first extruded position, the inside of the pile foundation is excavated. The at least one expanding arm (5) is expanded to the second extruded position, Using the drill head (100) at the second extruded position, excavation is performed below the pile foundation. Use of the drill head (100) according to any one of claims 1 to 8.

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