Drill head for a drilling device for producing drill holes in a construction ground

Abstract

The present invention relates to a drill head 10 for a drilling device for creating boreholes in a subsoil, in particular a subsoil with insufficient load-bearing capacity, which drill head 10 can be mounted on a drill pipe and comprises at least one arc-shaped plate 20, the surface of which acts as a screw surface during the drilling process. The present invention also relates to a reinforcement cage 30 comprising a splitting element 32, which reinforcement cage 30 is suitable for use both with and without the drill head 10 according to the invention.

Description

Technical field of the invention

[0001] The present invention relates to a drill head for a drilling device for creating boreholes in a subsoil, in particular a subsoil with insufficient bearing capacity, which drill head can be mounted on a drill pipe and comprises at least one arc-shaped plate whose surface acts as a screw surface during the drilling process. The present invention also relates to a reinforcement cage comprising a splitting element, which reinforcement cage is suitable for use with the drill head according to the invention. State of the art

[0002] If the soil at the foundation depth of a construction project proves insufficient to bear the loads of the building, or if excessively large settlements are expected, foundation or displacement bored piles can be used. These transfer the building loads to deeper, more load-bearing soil layers.

[0003] These types of foundation or displacement bored piles are constructed using a drill head and a drill casing that is sealed watertight. A drilling rig drives the drill casing and the drill head, which is detachably and securely attached to it against rotation and tilting, into the ground under high vertical pressure to the required depth. This process displaces soil material equal to the volume of the drill casing. Once the required depth is reached, prefabricated pile reinforcement, such as a reinforcement cage, a single reinforcing bar, or a steel profile, etc., can be inserted into the drill casing, which is then filled with concrete. Alternatively, fiber-reinforced concrete mixed with steel and / or plastic fibers can be used instead of the aforementioned prefabricated pile reinforcement.While continuously rotating, the drill pipe can then be withdrawn from the ground, at which point the connection between the pipe and the drill head detaches, leaving the latter as a lost component in the ground. The concrete inside the drill pipe flows into the resulting cavity in the soil as it is withdrawn, filling it to the required level. After the concrete has hardened, a load-bearing, possibly reinforced, foundation or displacement pile is formed.

[0004] Drill heads for such applications are known in various designs. For example, EP 3 216 974 B1 shows a symmetrically designed drill head that is assembled from several plates only at the point of use and can be inserted into the ground efficiently and quickly by means of arc-shaped plates that act as screw surfaces during the drilling process. In this way, high cost efficiency can be achieved in transport and storage as well as in the construction of the foundation pile.

[0005] EP4227467A1 also discloses a one-piece drill bit which, due to its asymmetrical design, achieves an increased drilling and displacement effect. The tendency of the drill bit to tilt (rock) from the drill pipe caused by the asymmetrical design is prevented by a tilt-proof connection between the drill bit and the drill pipe. However, such drill bits, manufactured as cast parts, do not achieve the necessary fracture resistance, cost-efficiency, or versatility of composite drill heads.

[0006] Based on the prior art, the present invention therefore aims to overcome the aforementioned disadvantages and to design a drill head in such a way that it exhibits maximum fracture resistance, is cost-effective to manufacture, store, and transport, is modularly expandable, and can be used efficiently. The drill head according to the invention must also be able to withstand the rocking effect in order to enable asymmetrical designs and thus be suitable for use on the widest possible range of soil types. Summary of the invention

[0007] According to the invention, these objectives are achieved primarily through the subject matter of the independent claims. Further advantageous embodiments are also apparent from the dependent claims and the description.

[0008] In particular, some of these objectives are achieved by a drill head for a drilling device for creating boreholes in a subsoil, wherein the drill head can be placed on a drill pipe of the drilling device and forms a detachable connection with the drill pipe that is secured against rotation, and wherein the drill head has a base plate with which the end of the drill pipe can be closed, onto which base plate at least a first drill head plate oriented substantially perpendicular to it and a second drill head plate arranged substantially perpendicular to the first drill head plate can be placed, wherein at least one arc-shaped plate can be placed on the head sides of these drill head plates, which extends over all flanks of the drill head plates, and wherein the arc-shaped plate is designed such that its surface acts as a screw surface during the drilling process.

[0009] This design of the drill head ensures that, on the one hand, the rotating drill head, set in motion by the drilling device, can penetrate the ground quickly and efficiently via the surface of the arc-shaped plate, which acts as a screw-like surface. On the other hand, the arc-shaped plate, by extending over all flanks of the drill head plates, increases the stability of the drill head. The arc-shaped plate can be attached to the first and / or second drill head plates by welding, screwing, bolting, or another suitable connection.

[0010] In a preferred embodiment, at least one first drill head plate oriented essentially perpendicular to the base plate and a second drill head plate arranged essentially perpendicular to the first drill head plate can be placed on the base plate, wherein these first and second drill head plates are provided with slot-shaped recesses such that the drill head plates can be inserted crosswise into one another, thus achieving a simple and stable construction of the drill head.

[0011] Advantageously, the areas of the first and second drill head plates facing away from the base plate are tapered to a point, thus ensuring easy penetration of the drill head into the ground. For improved drilling performance, at least one of the drill head plates can have a base body that is asymmetrical with respect to a drilling axis, thereby achieving an additional displacement effect. The shape of the drill head plates can be selected depending on the type of soil being drilled.

[0012] Particularly in conjunction with the tapered shape, the arc-shaped plate is pressed against the tapered first and second drill head plates by the resistance generated by the subsoil during the drilling process and acting on the surface of the arc-shaped plate, which acts as a screw surface.

[0013] In a further embodiment, it is provided that, in addition to the arc-shaped plate extending over all flanks of the drill head plates, at least one further arc-shaped plate is attached to a first drill head plate and / or a second drill head plate, which extends over at least one flank of a first drill head plate and an adjacent flank of a second drill head plate and whose surface also acts as a screw surface during the drilling process, which further improves the efficiency of the drilling process.

[0014] An advantageous embodiment of the invention consists in the fact that the at least one arc-shaped plate can be arranged or inserted in a suitable position on a first drill head plate and / or a second drill head plate by means of first and second holding means, wherein these first and second holding means are formed from recesses and / or projections provided in the respective arc-shaped plate or the drill head plates. Alternatively, the at least one arc-shaped plate can be arranged and held on the first drill head plate or the second drill head plate or several drill head plates by welding, bolting, or another suitable connection.

[0015] For use in dense soils, a further embodiment of the invention provides an additional plate, essentially parallel and flat against the base plate, on the side of the base plate facing away from the drill pipe. This further improves the stability of the drill head.

[0016] The invention also relates to the fact that the drill head can be detachably connected to the drill pipe in a manner that prevents rotation and / or tilting. For this purpose, connecting elements are provided on the first drill head plate, the second drill head plate, the base plate, and / or the additional plate such that these elements project radially beyond the base plate and / or the additional plate and can engage with corresponding elements provided at the end of the drill pipe. These connecting elements and the elements provided at the end of the drill pipe can be designed as projections, webs, or similar features and can vary in number and design.The connecting means can also be connected to the first drill head plate, the second drill head plate, the base plate and / or the additional plate by welding, screwing, bolting, or the like; likewise, the elements provided at the end of the drill pipe can be connected to the drill pipe by welding, screwing, bolting, or the like.

[0017] In a further embodiment of the invention, connecting means are provided on the first drill head plate and / or the second drill head plate such that these connecting means project through recesses provided in the base plate and through recesses provided in the additional plate, and the connecting means extend beyond the base plate in the direction of the drill pipe. They can be engaged with corresponding recesses provided at the end of the drill pipe and are held in the base plate by means of fixing elements. Detachable fixing elements such as screws, pins, bolts, and the like can be used for this purpose; however, it is also conceivable that a permanent connection, preferably a welded connection, is used as the fixing element. These connecting means for connecting the drill head to the drill pipe can be designed as projections, webs, or similar features and, for example, may have an approximate L-shape.At least one of these connecting elements projects at least partially beyond the base plate over a defined length in the direction of the drill pipe, forming a contact surface with the inner circumference of the drill pipe. However, it is also conceivable that the connecting elements are attached to the base plate or the additional plate, and that the base plate and / or the additional plate are firmly connected to the first and second drill head plates, for example, by welding, bolting, screwing, or other suitable fasteners. The number and design of the connecting elements can vary. For further stabilization, it is conceivable to connect individual connecting elements to each other using ring-shaped elements, rods, or similar components. In this way, the rotational movement applied to the drill pipe by the drilling rig can be optimally transferred to the drill head.In addition, this allows forces acting eccentrically on the drill head relative to a drilling axis to be absorbed and prevents the drill head from tipping under the drill pipe.

[0018] A further advantageous embodiment of the invention is that the drill head plates, the base plate, the additional plate and the arc-shaped plates can be manufactured by cutting them from commercially available semi-finished products, which enables cost-efficient production of these.

[0019] According to one embodiment, the drill head includes connecting elements for linking it to a reinforcement cage. To construct a cast-in-place concrete pile in a borehole created using a drill head according to the invention, a reinforcement cage can be inserted into the drill pipe, and the drill pipe can then be filled with concrete. The connecting elements for linking the drill head to the reinforcement cage fix the cage in the borehole in such a way that it cannot rise into the borehole when the concrete is poured, thus enabling the production of a high-quality cast-in-place concrete pile.

[0020] Another aspect of the invention relates to a reinforcement cage suitable for use with the drill head according to the invention, which reinforcement cage is characterized in that at least one splitting element can be arranged on the reinforcement cage. A corresponding splitting element can be movably or rigidly connected to the reinforcement cage at the end opposite the drill head in such a way that, when the drill pipe is filled with concrete, the proportion of concrete in the cross-section of the cast-in-place pile is reduced in the area of ​​the splitting element. In this way, a predetermined breaking point is formed in the cast-in-place pile, which facilitates subsequent splitting of the cast-in-place pile at this predetermined breaking point. The at least one splitting element does not necessarily have to be arranged on the reinforcement cage during the filling of the drill pipe with concrete, but can also be subsequently inserted into the still uncured concrete along with the reinforcement cage and arranged on the reinforcement cage.

[0021] Preferably, the splitting element can be connected to the longitudinally extending elements of the reinforcement cage in such a way that the splitting element forms a termination of the reinforcement cage and, insofar as a correspondingly reinforced cast-in-place concrete pile is split at the predetermined breaking point, the splitting element covers the longitudinally extending elements of the reinforcement cage, thus reducing the risk of injury from reinforcement elements protruding from the cast-in-place concrete pile. In this sense, a dedicated splitting element can be provided for each longitudinally extending element of the reinforcement cage, or a single splitting element can be provided for several longitudinally extending elements of the reinforcement cage.

[0022] Furthermore, at least one gap element can extend radially beyond the cross-section of the reinforcement cage and interact with the drill pipe in such a way that the reinforcement cage is centered and aligned within the drill pipe.

[0023] Further details of the invention will become apparent from the following description of the preferred embodiments, which are illustrated by way of example in the drawings. The description also reveals further advantages of the present invention, as well as suggestions and proposals on how the subject matter of the invention can be modified or further developed within the scope of the claim. Brief description of the drawings

[0024] One embodiment of the invention is explained in more detail below by way of example with reference to the accompanying drawing.

[0025] It shows Figure 1 a perspective view of a drill head according to an embodiment of the invention, Figure 2 a top view of a drill head according to an embodiment of the invention, Figure 3 a view from below of a drill head according to an embodiment of the invention, Figure 4 a reinforcement cage according to the invention, Figure 5aa cross-section of a cast-in-place concrete pile with reinforcement elements at a first position, and Figure 5b a cross-section of a cast-in-place concrete pile with reinforcement elements and a splitting element at a second position. Preferred embodiments of the invention

[0026] Figure 1 Figure 1 shows a perspective view of a drill head 10 according to an embodiment of the invention, in which the drill head 10 can be placed on a drill pipe (not shown) and forms a detachable connection with the drill pipe that is secured against rotation, and wherein the drill head 10 has a base plate 13 with which the end of the drill pipe can be closed. The drill head 10 also comprises a first drill head plate 11 and a second drill head plate 12 arranged perpendicular to it, which are inserted crosswise into one another, and which are arranged on a base plate 13 and an additional plate 14 abutting the base plate 13 in parallel.

[0027] The drill head plates 11, 12 are tapered in their areas facing away from the base plate 13, and the first drill head plate 11 of the illustrated drill head 10 has a base body that is asymmetrical with respect to the drilling axis 5, thereby achieving an additional displacement effect. This additional displacement effect results in stronger forces acting on the drill head 10, which are absorbed by an arc-shaped plate 20 mounted on the head faces 15, 16 of the drill head plates 11, 12 and extending over all flanks of the drill head plates 11a-d, 12a-d, in order to counteract bending and / or shearing of the drill head plates. The additional plate 14 also counteracts these deformations and thus increases the stability of the drill head 10.

[0028] The surface of the arc-shaped plate 20 acts as a helical surface during the drilling process, thus facilitating the insertion of the drill head 10 into the ground. The illustrated drill head 10 also comprises further arc-shaped plates 21, 22, each extending over four flanks of the drill head plates 11, 12, and whose surfaces also act as helical surfaces during the drilling process. During assembly of the drill head, the arc-shaped plates 20, 21, 22 are fixed to the drill head plates 11, 12 by means of retaining elements. However, as soon as the drill head is inserted into the ground, the force exerted by the ground on the arc-shaped plates 20, 21, 22 via the surfaces acting as helical surfaces acts in such a way that the arc-shaped plates 20, 21, 22 are additionally fixed to the drill head plates 11, 12.

[0029] The base plate 13 and the additional plate 14 have recesses through which the L-shaped connecting elements 17, 18 of the drill head plates 11, 12 project. The radially outward-facing end faces of the legs 17a, 18a of the connecting elements 17, 18, which project through the base plate 13 and the additional plate 14, form contact surfaces with the inner surface of a drill pipe (not shown) for a tilt-proof connection of the drill head 10 to the drill pipe. For further stabilization of the drill head 10, the connecting elements 17, 18 are connected to each other by a connecting element 19, which is approximately designed as a ring. Further connecting elements (not shown) for connecting the drill head 10 to a reinforcement cage 30 can be provided, for example, on the connecting elements 17, 18, the connecting element 19, or the base plate 13.

[0030] Figure 2is a top view of the in Figure 1 The drill head 10 is shown, in which the connecting elements 17, 18, which are connected to each other by means of the connecting element 19, are particularly evident. By tilting the drill head 10 relative to the drill pipe (not shown), a radially inward force is exerted on one or more of the connecting elements 17, 18 via the end faces of the legs 17a, 18a, which act as contact surfaces and point radially outwards. Thanks to the connecting element 19, this force can be transferred from one of the connecting elements 17, 18 to all of them, thus increasing the stability of the drill head 10.

[0031] In the Figure 3In the illustrated view of a drill head 10 according to an embodiment of the invention, the arc-shaped plate 20, which is mounted on the drill head plates 11, 12, is visible from below. In particular, the arc-shaped plate 20, which extends over all flanks 11a-d, 12a-d of the drill head plates 11, 12, is visible, thereby stabilizing the crosswise arrangement of the drill head plates 11, 12 against any transverse forces.

[0032] Figure 4 Figure 1 shows a reinforcement cage 30 suitable for use with the drill head 10 according to the invention, on which a splitting element 32 designed as a ring is arranged. The splitting element 32 is rigidly connected by means of screws to several elements 33 extending in the longitudinal direction D of the reinforcement cage 30 and forms a termination of the reinforcement cage 30 at a first end 34.

[0033] At a second end 35 of the reinforcement cage 30, opposite the first end 34, an anchor ring 21 is arranged, which can interact with additional connecting means (not shown) arranged on a drill head 10 in such a way that the reinforcement cage 30 is connected to a drill head 10.

[0034] Out of Figures 5a and 5b It is evident that the splitting element 32 reduces the proportion of concrete 41 in the cross-section of the cast-in-place concrete pile 40 in the area of ​​the splitting element 32, thereby creating a predetermined breaking point in the cast-in-place concrete pile, which promotes a subsequent splitting of the cast-in-place concrete pile at this predetermined breaking point.

Claims

1. Drill head (10) for a drilling device for creating boreholes in a subsoil, wherein the drill head (10) can be placed on a drill pipe of the drilling device and forms a detachable connection with the drill pipe that is secured against rotation, and wherein the drill head (10) has a base plate (13) with which the end of the drill pipe can be closed, onto which base plate (13) at least a first drill head plate (11) oriented substantially perpendicular to it and a second drill head plate (12) arranged substantially perpendicular to the first drill head plate (11) can be placed, characterized by the fact that at least one arc-shaped plate (20) can be placed on the head sides (15, 16) of these drill head plates (11, 12), which extends over all flanks of the drill head plates (11a-d, 12a-d), and that the arc-shaped plate (20) is designed such that its surface acts as a screw surface during the drilling process.

2. Drill head (10) according to claim 1, characterized by the fact thatthe drill head plates (11, 12) are provided with slot-shaped recesses such that the drill head plates (11, 12) can be inserted crosswise into one another.

3. Drill head (10) according to claim 1 or 2, characterized by the fact that the areas of the first drill head plate and the second drill head plate facing away from the base plate (13) are tapered to a point.

4. Drill head (10) according to one of the preceding claims, characterized by the fact that at least one of the drill head plates (11, 12) has a base body that is asymmetrical with respect to a drill axis (5).

5. Drill head (10) according to one of the preceding claims, characterized by the fact that at least one further arc-shaped plate (21, 22) is provided, which extends at least over one flank (11a-d, 12a-d) of a first drill head plate (11, 12) and an adjacent flank (11a-d, 12a-d) of a second drill head plate (11, 12) and whose surface acts as a screw surface during the drilling process.

6. Drill head (10) according to one of the preceding claims, characterized by the fact that The first holding means and the second holding means are formed from recesses and / or projections provided in the respective arc-shaped plates (20, 21, 22) or the drill head plates (11, 12).

7. Drill head (10) according to one of the preceding claims, characterized by the fact that An additional plate (14) is provided on the side of the base plate (13) facing away from the drill pipe, and is essentially parallel to the base plate (13).

8. Drill head (10) according to one of the preceding claims, characterized by the fact that Connecting means are provided on the first drill head plate (11), the second drill head plate (12), the base plate (13) and / or the additional plate (14) such that they project radially beyond the base plate (13) and / or the additional plate (14) and can be engaged with corresponding elements provided at the end of the drill pipe.

9. Drill head (10) according to one of the preceding claims, characterized by the fact that Connecting means (17, 18) are provided on the first drill head plate (11) and / or the second drill head plate (12) such that these connecting means (17, 18) extend through recesses attached to the base plate (13) and through recesses attached to the additional plate (14), and the connecting means (17, 18) extend beyond the base plate (13) in the direction of the drill pipe and can engage with corresponding recesses attached to the end of the drill pipe.

10. Drill head (10) according to claim 9, characterized by the fact that Connecting means (17, 18) are designed to form a contact surface with an inner circumference of the drill pipe.

11. Drill head (10) according to claim 9 or 10, characterized by the fact thatConnecting means (17, 18) are designed as L-shaped projections, wherein a leg (17a, 18a) extending vertically through the base plate (13) forms the contact surface with an inner circumference of the drill pipe.

12. Drill head (10) according to one of the preceding claims, characterized by the fact that the connecting means (17, 18) are held in the base plate (13) by means of fixing means.

13. Drill head (10) according to one of claims 9 to 12, characterized by the fact that on the side of the base plate (13) facing the drill pipe at least one additional connecting element (19) is provided such that the connecting means (17) provided on the first drill head plate (11) and the connecting means (18) provided on the second drill head plate (12) can be connected to each other.

14. Drill head (10) according to one of the preceding claims, characterized by the fact thatthe drill head plates (11, 12), the base plate (13), the additional plate (14) and the arc-shaped plates (20, 21, 22) can be manufactured by cutting them from commercially available semi-finished products.

15. Drill head (10) according to one of the preceding claims, characterized by the fact that the drill head (10) includes connecting means for connection to a reinforcement cage (30).

16. Reinforcement cage (30) suitable for use with a drill head (10) according to claim 15, characterized by the fact that at least one splitting element (32) can be arranged on the reinforcement cage (30).

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