Drill head and drill 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 during operation about a rotation axis and expandable in terms of its effective drilling diameter, and which comprises a base body having an end face on which at least one cutting tool is mounted and at least one spreader arm pivotably connected to the base body about a pivot axis, the spreader arm being pivotable between a retracted position and a first extended position which expands the effective drilling diameter by a first value, the spreader arm having an active surface on which at least one cutting tool is mounted. [Background technology]

[0002] A drill head with these features is known from Korean Patent Publication No. 20060006754. In the retracted position, at least one cutting tool of the spreading arms is non-functional, while in the pushed-out position, during operation, a diameter expansion of the hole drilled by the base body is effected, following the hole bottom.

[0003] Such drill heads are used, for example, when drilling offshore foundations for wind power installations.

[0004] In the drive to increase the performance of wind power installations, especially those that are part of so-called "offshore wind farms", there is a trend towards larger and larger installations, so that their foundations must be designed to handle ever-increasing loads.

[0005] To meet this requirement, it is known, for example, to provide a foundation for a wind power installation with a number of piles, for example three piles arranged in a triangle, which are drilled into the seabed and protrude above the sea level, the upper ends of which are connected to one another via a support structure, to which the lower ends of the towers of the wind power installation are fixed. These foundations, also called "tripods", have the disadvantage, inter alia, of the high construction costs required due to the multiple foundation drilling required.

[0006] Therefore, the towers of wind power plants, which are often used today in offshore areas, are each fixed to the upper end of a single pile foundation (also called "monopile"). In order to obtain the necessary stability of these pile foundations, they have a diameter that is larger in the subsea area at least over the length of the pile foundation that is inserted into the seabed than the diameter of the respective upper end to which the towers of the wind power plants are fixed. Therefore, these pile foundations often have a "flange neck" that transitions between both areas of different diameters.

[0007] In order to drill these pile foundations, it is necessary to periodically drill and remove the seabed located inside the piles. For this purpose, it is necessary to introduce a drill head from above into the pile foundation through a small diameter area. Therefore, it is necessary to use a drill head of the type mentioned at the beginning, which allows the effective drilling diameter to be enlarged. Summary of the Invention [Problem to be solved by the invention]

[0008] The problem underlying the present invention is to provide an improved drill head for the above mentioned uses. [Means for solving the problem]

[0009] This problem is solved by a drill head as claimed in claim 1.

[0010] The drill head according to the invention is designed in such a way that the working surfaces of the spreading arms, in the retracted position, lie at least approximately in one plane together with the end face of the base body, "at least approximately" meaning that there should be no stepwise offset between the working surfaces of the spreading arms and the end face of the base body that is greater than the extension of the cutting tool in the direction of the rotation axis.

[0011] Due to this configuration, in the drill head according to the invention, the at least one cutting tool of the at least one spreading arm can also serve to scrape the ground at the bottom of the hole in its retracted position, whereby the drilling power that can be obtained with the drill head according to the invention is increased compared to prior art drill heads, in which the at least one cutting tool of the at least one spreading arm does not function in its retracted position.

[0012] Furthermore, the drill head according to the invention is designed in such a way that the working surface connects to the end face of the base body in the first extended position of the spreading arms at least approximately without a step-like offset in the direction of the rotation axis.

[0013] "At least approximately without a step-like offset" means that the step-like offset should not be greater than the extension of the cutting tool in the direction of the rotation axis. Without a step-like offset does not mean that the working surface and the end surface must be oriented parallel to one another. Rather, the working surface may be inclined relative to the end surface.

[0014] With this configuration, at least one cutting tool of at least one spreading arm in the first extended position works in a plane that opens at least approximately without a step-like offset into the plane in which at least one cutting tool of the base body works, so that when boring a hole with the spreading arm in the first extended position, a hole bottom is obtained that does not have a step-like offset in the horizontal direction of the enlarged diameter. However, the area of ​​the hole bottom provided by the at least one spreading arm may be inclined with respect to the area provided by the base body.

[0015] In a hole drilled with a drill head of the type mentioned at the beginning, the area of ​​the bottom of the hole drilled by the base body of the drill head precedes the area drilled by the spreading arms. However, this area is not required for boring a pile foundation, so that the necessary costs of a drill head of the type mentioned at the beginning are increased by the avoidable drilling time and the avoidable amount of cuttings to be removed, which is avoided by the drill head according to the invention.

[0016] In a preferred development of the drill head according to the invention, at least one spreading arm can be pivoted to a second, pushed-out position, which increases the effective drilling diameter of the drill head by a second value. Due to this configuration of the drill head, it is possible to first drill a hole through the inside of the pile foundation up to the lower end of the pile foundation with an effective drilling diameter increased by a first value and then drill the hole further with an effective drilling diameter increased by a second value. This makes it possible to significantly facilitate the penetration of the pile foundation up to the required final depth. The effective drilling diameter increased by a second value is therefore preferably selected such that it corresponds at least to the outer diameter of the pile foundation.

[0017] In another preferred embodiment of the drill head according to the invention, the working surface of at least one spreading arm in the first and / or second pushed-out position has an angle of 20° to 45° with respect to the end face of the base body, inclined from the end face towards the base body. By this measure, the area of ​​the hole bottom provided by the at least one spreading arm is raised by approximately the same angle with respect to the area provided by the base body. Surprisingly, it has been found that in this way the loosened cuttings can be removed from the hole bottom particularly effectively and thus the friction of the drill head during boring of the hole can be reduced. This preferred embodiment is thereby distinguished by a particularly low energy demand for boring of the hole and a particularly low wear of the drill head, in particular of the cutting tool.

[0018] In another preferred embodiment of the drill head according to the invention, a closing element is provided which at least approximately closes the clearance surface which occurs in the first and / or second extended position of the spreading arms between the end face and the working face, thereby preventing cuttings from penetrating through this clearance surface into the area of ​​the drill head, which would block the return movement of at least one spreading arm to the retracted position, which would make it difficult or even impossible to withdraw the drill head from the hole.

[0019] In a preferred embodiment of the drill head according to the invention, the at least one spreading arm has a side facing the rotation axis of the drill head, in which a first end of an operating lever is pivotally attached to the spreading arm so as to be movable about an axis extending approximately 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 transversely to the axis. Due to this configuration, the at least one spreading arm is connected to the base body in a particularly stable manner, so that forces acting on the at least one spreading arm in the first or second pushed-out position can be introduced into the base body without damage, even when drilling a hole in rock.

[0020] For moving the at least one spreading arm between the retracted position and the first and / or second extended position, a linear motor is preferably provided which is pivotally connected at a first end to the base body and at a second end to an operating lever. The term "linear motor" should not be understood as being limited to electrically operated motors but should be interpreted broadly. In particular, the term linear motor should also be understood to include hydraulic or pneumatic cylinders. In a particularly preferred embodiment of the drill head according to the invention, a hydraulic cylinder is provided which is pivotally connected 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 invention, the operating lever is designed in such a way that it forms the closing element, thereby avoiding the constructional costs associated with an additional closing element.

[0022] In an embodiment of the drill head according to the invention which is particularly suitable for boring holes also in rocky ground, at least part of the cutting tool is preferably designed as a rotary cutting tool.

[0023] In an embodiment of the drill head according to the invention, which 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 spreading arm are configured in such a way that the effective drilling diameter is expandable in the range of 5000-8000 mm. In one embodiment of the drill head according to the invention, for example, the effective drilling diameter can be 5150 mm in the retracted position of the at least one spreading arm, 6800 mm in a first pushed-out position expanded by a first value and 7400 mm in a second pushed-out position expanded by a second value.

[0024] The invention also relates to a drilling system, comprising a rotating device, a support system and a drill head according to the invention connected to the support system.

[0025] The drawing shows, purely diagrammatically, an embodiment of a drill head according to the invention. [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 shows a side view of an embodiment of a drill head according to the invention in the area of ​​a small diameter pile with the spreading arms in a retracted position. [Diagram 2] 2 is a bottom view of this embodiment of the drill head shown in FIG. 1 with the spreader arms in the retracted position. FIG. [Diagram 3] 2 shows the same embodiment of the drill head according to the invention in the area of ​​the large diameter of the pile with the spreading arms in a first, pushed-out position, in a view corresponding to FIG. 1 . [Figure 4] 4 shows the same embodiment of the drill head according to the invention in a view corresponding to FIG. 3 in position under the lower end of the pile with the spreading arms in a second, pushed-out position. [Diagram 5]FIG. 2 shows the same embodiment of the drill head according to the invention, viewed from below, with the horizontally extending spreading arms in a first extended position and the vertically extending spreading arms in a second extended position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] An embodiment of a drill head according to the invention, generally designated by the reference number 100 in the figures (hereinafter simply referred to as "drill head 100"), is connected during operation to a support system 1, shown diagrammatically in Fig. 1, which can be rotated about a rotation axis S by means of a rotation device, not shown, such that the drill head 100 can be rotated about the rotation axis S during operation.

[0028] The drill head comprises a base body 2 having an end face 4 on which a number of cutting tools 3 are mounted.

[0029] Furthermore, the drill head 100 has spreading arms 5 which are arranged offset from one another in the direction of rotation by 90° with respect to their central plane. Each spreading arm 5 is connected to the base body 2 by means of a pin 6 which defines a pivot axis W about which the respective spreading arm can be pivoted. The pivot axis W is oriented perpendicularly to the rotation axis S.

[0030] Each spreading arm 5 has a working surface 8 on which a number of cutting tools 7 are mounted.

[0031] Each spreading arm 5 can be pivoted about a pivot axis W between the retracted position shown in Figures 1 and 2, i.e. in which each working surface 8 and end surface 4 lie at least approximately in one plane E and the drill head has an effective drilling diameter D0 (see Figure 1), a first pushed-out position (see Figure 3), in which the effective drilling diameter D1 is enlarged by a first value B1, and a second pushed-out position (see Figure 4), in which the effective drilling diameter D2 is enlarged by a second value B2.

[0032] As can be seen in Figures 3 and 4, the active surface 8 of the spreading arm 5 extends from the end face 4 of the base body 2 at least approximately without a step-like offset in the direction of the rotation axis S only in the first pushed-out position (Figure 3) and in the second pushed-out position (Figure 4).

[0033] When the spreading arms 5 are in the first and second pushed-out position, the working surfaces 8 each have an angle α of 20° to 45°, preferably about 37°, relative to the end face 4 of the base body 2. In this way, the cuttings cut with the cutting tool 7 of the spreading arms 5 can reach the direction of the hole center under the action of gravity and can thus be relatively simply removed, for example by suction, via the suction opening 9 located at the end face 4 of the base body 2.

[0034] In order to be able to pivot the spreading arms 5 between a retracted position and a first and a second extended position, a hydraulic cylinder 10 is provided for each spreading arm 5. Each hydraulic cylinder is pivotally mounted at a first end 11 to the base body 2 and at a second end 12 to an operating lever 13.

[0035] Each operating lever 13 is attached with a first end 14 to the spreading arm 5 in the region of its side facing the axis of rotation S. A second end 15 of the operating lever 13 is supported in a guide 16 on the base body 2 so as to be movable parallel to the axis of rotation S.

[0036] As can be seen by comparing FIGS. 1, 3 and 4, a change in length of the hydraulic cylinders causes, with this arrangement, a pivoting movement of the spreading arms 5 about a pivot axis W.

[0037] The operating levers 13 are designed in such a way that they at least approximately close the clearances which arise in the first and second pushed-out positions between the end face 4 of the base body 2 and the working faces 8 of the spreading arms 5. As a result, the operating levers 13 simultaneously serve to form closure elements 17 which prevent the intrusion of cutting material into the base body 2 and, if this results in, blocking of the spreading arms 5. [Explanation of symbols]

[0038] 100 Drill Head 1 Support system 2 Base body 3 cutting tools 4 End face 5 Spreading arms 6-pin 7 Cutting tools 8 Working surface 9 Suction 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 Swivel axis α angle

Claims

1. A drill head (100) which, during operation, is rotatable about a rotation axis (S) and has an effective drilling diameter (D ０ , D １ , D ２ ) can be expanded, a base body (2) having an end face (4) on which at least one cutting tool (3) is mounted; At least one spreading arm (5) pivotably connected to the base body (2) about a pivot axis (W), the spreading arm (5) being adapted to have a retracted position and a retractable position for adjusting the effective drilling diameter to a first value (B １ ) to a first pushed-out position, A drill head (100), wherein the at least one spreading arm (5) has a working surface (8) on which at least one cutting tool (7) is mounted, the working surface (8) lies at least approximately in one plane (E) together with the end surface (4) of the base body (2) in the retracted position of the at least one spreading arm (5); and The drill head (100), characterized in that in the first pushed-out position of the at least one spreading arm (5), the working surface (8) extends from the end face (4) of the base body (2) at least approximately without a step-like deviation in the direction of the rotation axis (S).

2. The at least one spreading arm (5) has a second value (B ２ 2. The drill head of claim 1, wherein the drill head is pivotable to a second, extended position, the second, extended position being expanded by an amount equal to the drill head diameter.

3. 3. The drill head according to claim 1 or 2, wherein the working surface (8) of the at least one spreading arm (5) in the first and / or second extended position has an angle (α) of 20° to 45° with respect to the end face (4) of the base body (2) and is inclined from the end face (4) towards the base body (2).

4. 4. The drill head according to claim 1, further comprising a closing element (17) which at least substantially closes a clearance surface which occurs in the first or second pushed-out position of the at least one spreading arm (5) between the end face (4) and the working surface (8).

5. 5. The drill head according to claim 1, wherein the at least one spreading arm (5) has a side facing the rotation axis (S), and in the region of this side, a first end (14) of an operating lever (13) is pivotally attached to the at least one spreading arm (5) so as to be pivotable about an axis extending approximately parallel to the pivot axis, and a second end (15) of the operating lever (13) is pivotally attached to the base body (2) so as to be movable along a guide (16).

6. 6. The drill head according to claim 5, further comprising a linear motor pivotally connected at a first end (11) to the base body (2) and at a second end (12) to the operating lever (13), the linear motor preferably including a pneumatic cylinder, particularly preferably a hydraulic cylinder (10).

7. 7. Drill head according to any one of claims 4 to 6, characterized in that the operating lever (13) is dimensioned such that it forms the closure element (17).

8. 8. Drill head according to claim 1, characterized in that at least some of the cutting tools (3, 7) are formed as rotary cutting tools.

9. Drill head according to any one of the preceding claims, wherein the effective drilling diameter is scalable from 5000 to 8000 mm.

10. A drilling system including a rotating device and a support system (1), The drilling system further comprises a drill head (100) according to any one of claims 1 to 9, characterized in that the drill head (100) is connected to the support system (1).

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