Box drill and method for making a hole in the ground

Abstract

The invention relates to a box drill with a housing having a receiving chamber designed to receive the removed soil material, a soil removal device arranged at a lower area of ​​the box drill below the housing and designed to remove soil material, at least one passage designed to allow the removed soil material to pass from the soil removal device into the receiving chamber during drilling, and a closing device for closing the at least one passage when the box drill is pulled out of the borehole.According to the invention, a tubular central shaft is formed on the housing as a compensating channel, which extends from at least one lower channel opening, which is arranged below or on the closure device, to at least one upper channel opening, which is arranged above the receiving space, wherein the compensating channel is designed to allow a medium to flow between the lower area and an upper area of ​​the box drill when the box drill is pulled and / or lowered in the borehole.

Description

[0001] The invention relates to a box drill with a housing having a receiving space which is designed to receive the removed soil material, a soil removal device which is arranged in a lower region of the box drill below the housing and is designed to remove soil material, at least one passage which is designed to allow the removed soil material to pass from the soil removal device into the receiving space during drilling, and a closure device for closing the at least one passage when the box drill is pulled out of the borehole, according to the preamble of claim 1.

[0002] Furthermore, the invention relates to a method for creating a borehole in the ground according to claim 12.

[0003] For example, to create foundation piles using a drilling rig in the ground, it is common practice to create a hole in the ground using a soil preparation tool, such as a box auger, often also called a drilling bucket. Depending on the type of surrounding soil, the borehole can be cased or uncased. Especially in the case of an uncased borehole, a support fluid must be provided to support the borehole against collapse.

[0004] When using a box auger, discontinuous drilling must be performed. During the drilling process, the box auger fills with excavated soil material, particularly until it is completely or at least largely full. The box auger is then withdrawn from the fluid-filled hole, with a drilling rig above the surface pivoting to a discharge position where the box auger can be emptied. The box auger is then pivoted back and retracted into the borehole to perform the next drilling step.

[0005] When creating a hole in the ground that is filled with a supporting fluid, there is the problem that when the soil tillage device is pulled back, a vacuum can build up below the soil tillage device in the hole. If this vacuum becomes too great, soil material can collapse from the side walls into the hole. This collapsed soil material not only means additional work to retrieve it from the hole. In fact, such a collapse carries the risk of a so-called ground failure, whereby the material that has collapsed into the hole weakens and destabilizes the surrounding soil to such an extent that major settlement movements occur in the area surrounding the hole. This can damage existing structures or cause construction machinery to topple over. A ground failure poses a significant danger to people and property, so comprehensive precautions must be taken to prevent such a ground failure.

[0006] To avoid such a danger caused by the development of negative pressure under a tillage device during upward pulling, it is known to keep the retraction speed of the tillage tool low so that sufficient pressure equalization can occur between the top and bottom of the tillage device in the hole. Another aspect of filling can be the disruptive edge in the interior of the box auger, against which the soil is pressed during filling. This can break the "filling chip" and lead to an undefined filling with a poor filling degree due to inhomogeneous porosity and material compaction. Asymmetrical suction on the underside of the auger can also lead to asymmetric flows, i.e., larger negative pressures can develop locally on the borehole wall, which in turn can lead to detachments on the borehole wall.

[0007] Furthermore, it is known from EP 3 879 064 A1, for example, to provide a lateral recess on a box drill bit, which allows fluid flow along the drilling bucket between the top and bottom. This limits the available space. Furthermore, partial lateral flow around the circumference of the box drill bit can deflect it from its center position in the borehole. This can lead to undesirable tilting in the borehole and increased wear on the drilling tool and casing, as well as increased force required to pull the drilling tool out of the borehole.

[0008] Another box auger with an approximately annular outer passage gap for fluid flow along the box auger is disclosed in DE 34 40 727 A1. US 9,309,736 B2 proposes an axial separating drilling bucket for drilling large holes in the ground. EP 4 015 766 B1 relates to a civil engineering tool for attachment to a civil engineering machine with a carrier device.

[0009] The invention is based on the Task The aim is to provide a box drill and a method with which a hole in the ground can be created in a particularly efficient manner.

[0010] The object is achieved, on the one hand, by a box drill having the features of claim 1 and, on the other hand, by a method having the features of claim 12. Preferred embodiments of the invention are specified in the dependent claims.

[0011] The box drill according to the invention is characterized in that a tubular central shaft is formed on the housing as a compensation channel, which extends from at least one lower channel opening, which is arranged below or on the closure device, to at least one upper channel opening, which is arranged above the receiving space, wherein the compensation channel is designed for the flow of a medium between the lower region and an upper region of the box drill when pulling and / or lowering the box drill in the borehole.

[0012] A basic idea of ​​the invention is to provide a compensating channel in a tubular central shaft in a box drill as a drilling tool with a lower closure device, with which at least one passage to the receiving space can be closed downwards, which has at least one lower channel opening in the lower region of the drilling tool and an upper channel opening in an upper region of the drilling tool. Through the compensating channel, a targeted central compensating flow can occur between the top and bottom of the drilling tool, particularly when pulling, but in principle also when lowering, the drilling tool in a bore filled in particular with suspension or liquid, with a closed passage of the receiving space.When pulling out a drilling tool that largely covers the bore diameter and can act like a plug when the passage is closed, pressure can be equalized between the area below the drilling tool and the area above it. This counteracts an undesirable suction effect when pulling out the drilling tool, which could damage a borehole wall. A connecting device can be arranged at the top of the box drill for detachable connection to a drill rod.

[0013] By creating a central flow through the central shaft, the risk of the drilling tool becoming jammed in the borehole during vertical movement is counteracted particularly reliably compared to lateral flow channels. This is gentle on the drilling tool and the borehole wall. Overall, a central compensation channel in a tubular central shaft with at least one lower channel opening and at least one upper channel opening achieves efficient central flow around or through the drilling tool to equalize pressure or flow during vertical movement in the borehole. This allows for energy-saving, faster, and problem-free movement of the drilling tool in the borehole. Although the central shaft reduces the interior space and also leads to an increased inner wall surface, which can be disadvantageous when emptying in cohesive soils, this is clearly outweighed by the advantages outlined above.

[0014] A particularly preferred embodiment of the invention is that the lower channel opening and / or the upper channel opening are closable. Particularly during the actual drilling process, in which soil material is removed in the lower region of the drilling tool, it may be useful to close the lower channel opening. This prevents soil material from penetrating the channel opening and potentially clogging the compensation channel. Closing the upper channel opening may also be useful to prevent the penetration or sedimentation of settled soil material from a drilling slurry and potentially clogging the upper channel opening or the channel from above.

[0015] A particularly useful design of the drilling tool is achieved according to a further development of the invention in that the closure device for closing the passage to the receiving space is also designed to close / open the lower channel opening. The closure device serves in a basically known manner, for example in a box drill, to keep a passage open during drilling for the excavated soil material to pass into the receiving space of the box-shaped housing and to close the passage after completion of the drilling step. In the closed position, this prevents loose excavated soil material from falling back into the borehole from the receiving space of the drilling tool when the drilling tool is withdrawn from the borehole.The closure device is efficiently designed such that it is not only designed to close and open the passage to the receiving space, but also to close and open the lower channel opening. The lower channel opening can be arranged, in particular, close to the at least one passage to the receiving space, in particular in an area below the passage to the receiving space.

[0016] According to one embodiment of the invention, it is particularly expedient for the closure device to have a closure element which is adjustable between a closure position in which the passage to the receiving space is closed by the closure element and a drilling position in which the passage is open for the passage of soil material into the receiving space during drilling.

[0017] It is particularly preferred that the lower channel opening is closed in the drilling position of the closure element, and that the lower channel opening is open in the closed position of the closure element. Thus, the passage and the lower channel opening can be alternately actuated by the closure element. This means that during drilling, in the drilling position of the closure element, the passage is open and the lower channel opening is closed simultaneously. In the closed position of the closure element, the passage to the receiving space is closed, while the lower channel opening is open for flow and / or pressure equalization through the equalization channel.

[0018] The closure element can, in principle, be designed in any suitable manner. According to one embodiment of the invention, a particularly robust arrangement is achieved by designing the closure element as a rotating base that can be rotated between the closed position and the drilling position. A rotational axis of the rotating base is, in particular, coaxial with the center and drilling axis of the drilling tool.

[0019] A further preferred embodiment of the drilling tool according to the invention consists in that a cover, in particular a cover plate, is arranged on an upper region of the housing, which closes off the receiving space at the top and separates it from the upper channel opening. In a box drill, this can be the upper housing cover of the box-like drilling bucket.

[0020] At least one upper channel opening is located above the cover plate. This ensures that excavated soil cannot penetrate into the upper receiving opening if the receiving space becomes overfilled.

[0021] The drilling tool is generally interchangeably attached to a drill rod or drive rod, in particular a Kelly bar, of a drilling rig. A particularly expedient embodiment of the invention is that the connecting device has a Kelly connection. A Kelly connection comprises, in particular, a polygonal, in particular a square connection, wherein a connecting sleeve with a polygonal or square receiving hole for a complementary connecting pin on the drill rod is preferably formed on the drilling tool. This polygonal plug connection achieves a rotationally fixed connection. Axial securing and connection can be achieved by one or more insertable cross bolts.

[0022] The drilling tool is designed as a drilling bucket with a peripheral wall that encloses the receiving space like a housing. The tubular central shaft of the box drill according to the invention extends centrally through the preferably cylindrical receiving space. The upper channel opening of the central compensation channel is located above the cover or the upper cover plate of the drilling bucket. A drilling bucket can also be referred to as a box drill.

[0023] A further preferred embodiment of the invention consists in that a folding floor is arranged on a lower region of the housing, which closes off the receiving space at the bottom and can be folded between a drilling position, in which the folding floor is locked in a receiving position, and an emptying position, in which the folding floor is unlocked and folded open to empty the receiving space. A folding floor is generally known from box drills. The folding floor is hinged or pivoted between the closed receiving position and an open emptying position via a pivot joint on the housing. In the closed receiving position, the folding floor is locked via a locking device. The locking device can have a rod which extends along the box drill up to an upper end region.By applying pressure to the locking rod, the folding floor can be unlocked and pivoted downward into its emptying position. After emptying, the folding floor can be pivoted shut again, for example, by pressing the box drill on the drilling rig against the floor. The folding floor closes and is then relocked in its closed receiving position.

[0024] The closure element, which can be designed as a rotating base, can preferably be rotatably mounted on the folding base. Removal elements for removing soil material can be arranged on the closure element. When the box drill is moved in a rotating manner during drilling, the rotatably mounted closure element can be pressed into its open position, in which the passage to the receiving space in the housing is released for receiving the removed soil material. Once the receiving space is filled, the closure element, designed as a rotating base, can be rotated into a closed position by an opposite rotary movement, in which the closure element closes off the passage. At the same time, this adjusting movement can be used to move the lower channel opening from a closed position into an open position during drilling.In this open position, the compensation channel is then open from bottom to top, so that when the box drill is pulled out of the borehole filled with suspension, an undesirable suction effect can be avoided or significantly reduced.

[0025] A further preferred embodiment of the box auger according to the invention is that the receiving space is annular, with the housing having an outer peripheral wall and an inner peripheral wall formed by the central shaft. The annular receiving space in the housing can thus provide sufficient space for receiving removed soil material. Flow can occur centrally through the box auger, so that undesirable tilting during extraction due to asymmetrical forces can be largely avoided.

[0026] According to a further embodiment of the invention, it is advantageous that a cover hood provided with lateral through-openings is arranged at the lower channel opening. The preferably cylindrical cover hood can axially close off the central shaft and thus the compensation channel at the bottom, so that during drilling soil material cannot be directly pressed into the outlet channel and thus closed off. One or more through-openings can be formed in a side wall of the preferably cylindrical cover hood, through which a liquid can flow laterally when the drill is lowered into the cover hood or when pulled out of the cover hood and thus into or out of the compensation channel. The lateral, preferably window-like through-openings can be closed with a closing slide, which can be designed together with the closing element designed as a rotating base.The design can in particular be designed in such a way that the passage to the receiving space and the passage openings for opening the lower channel opening can be opened and closed alternately.

[0027] The invention further comprises a drilling rig in which the drilling tool according to the invention is arranged. A drilling rig can, in particular, have a carrier unit, which can preferably comprise a chassis, in particular a crawler chassis, and a superstructure rotatably mounted thereon. A mast, which is essentially vertical during operation, can be attached to the superstructure, preferably via an adjustment mechanism. A rotary drive for rotating a drill rod can be arranged on the carrier unit. The drilling tool according to the invention can be detachably attached to the underside of the drill rod.

[0028] The drilling drive can preferably be movable and / or guided along the mast. The drilling rig is designed in particular for drilling into the ground, preferably for creating boreholes for foundation piles.

[0029] The invention further comprises a method for creating a borehole in the ground, in particular for discontinuous drilling, using the box auger or the drilling device according to the invention. The box auger removes soil material by rotating the auger, thus creating the borehole. During discontinuous drilling, a receiving space on the box auger is filled with the removed soil material and, after closing the passage, is withdrawn from the borehole for emptying.

[0030] The emptied drilling tool is then returned to the borehole for the next drilling step. This process is repeated until the desired final depth of the borehole is reached. Drilling can be performed either as a cased drill with a support tube or as an uncased drill.

[0031] One embodiment of the method according to the invention consists in opening the passage to the receiving chamber and closing the lower channel opening when removing soil material during drilling. Thus, the removed soil material can be collected in the receiving chamber while simultaneously closing the lower channel opening, preventing soil material from penetrating the channel opening.

[0032] A further advantageous embodiment of the invention is that, when the drilling tool is withdrawn, the passage to the receiving chamber is closed and the lower channel opening is opened. This ensures that no soil material can fall through the passage and out of the receiving chamber when the drilling tool is withdrawn.

[0033] By opening the compensation channel, the undesirable suction effect caused by the free channel opening can be largely avoided during extraction. Overall, this allows for faster extraction of the drilling tool and thus more efficient borehole creation. Furthermore, the risk of the borehole wall collapsing and ground failure due to negative pressure at the borehole wall is reduced.

[0034] According to a further development of the method according to the invention, it is advantageous for the compensation channel to be opened when lowering the drilling tool into the borehole. The passage can be either closed or open. The open compensation channel during lowering also allows for a faster workflow and thus more efficient drilling.

[0035] The invention will be further explained below with reference to a preferred embodiment, which is schematically illustrated in the accompanying drawings. In the drawings: Fig. 1 is a perspective view of a drilling tool according to the invention, which is designed as a box drill; Fig. 2 is a side view of the drilling tool of Fig. 1 ; Fig. 3 a cross-sectional view of the drilling tool of Fig. 1 ; and Fig. 4 a view of the drilling tool of the Figures 1 to 3 from underneath.

[0036] An embodiment of a drilling tool, which is designed as a box drill 10 according to the invention with a box-like housing 14, is shown in Figures 1 to 4. The box drill 10 has a tubular central shaft 30 which extends along a drilling or central axis. A soil removal device 20 is arranged at a lower end region of the drilling tool. The soil removal device 20 can have holders 22 to which removal elements 24 are releasably inserted. In the illustrated embodiment, the removal elements 24 are designed, for example, as round-shank chisels. Furthermore, a centering or pilot point 26 can be arranged at the lower end of the central shaft 30.

[0037] At the lower end of the housing 14 of the box drill 10, a closure device 50 with a hinged base 51 is arranged. The hinged base 51 is pivotally connected to the housing 14 via a pivot joint 54, allowing it to pivot between a shown closure position and an emptying position. A plate-shaped closure element 52 can be rotatably mounted on the underside of the hinged base 51. With the plate-shaped closure element 52, a passage 28 in the hinged base 51 can be opened or closed by a twisting movement.

[0038] In the figures, the box drill 10 is shown with the closure device 50 in an open or drilling position, in which the passage 28 is released or open. Thus, removed soil material from the removal device 20 can enter through the passage 28 into an annular receiving space 40 located above.

[0039] The box drill 10 can have a connecting device 45 with a receiving sleeve 47 at its upper end, wherein the connecting device 45 can be designed as a Kelly connection in a known manner. A complementary connecting pin of a drill rod of a drilling rig can be inserted into the receiving sleeve 47 with a square hole to create a rotationally fixed connection. An axially fixed connection can be formed via locking bolts (not shown), which can be inserted into transverse bores 49 on the receiving sleeve 47.

[0040] During drilling, the drilling tool is driven to rotate about the central axis, whereby soil material removed by the removal device 20 can enter upwards through the passage 28 into the annular receiving space 40, which is formed by the free space between an outer peripheral wall 16 of the housing 14 and the inner tubular central shaft 30.

[0041] Within the tubular central shaft 30, a compensating channel 32 extends along the central axis, which is closed at its lower end in the region of a lower channel opening 34 by a cover 56 with lateral, window-like through-openings 58. The preferably cylindrical or pot-shaped cover 56 can be connected in a rotationally fixed manner to the hinged base 51, wherein the plate-shaped closure element 52 can be rotatable relative to the hinged base 51 and the cover 56. The lateral, preferably window-like through-openings 58 on the cover 56 can be closed with a closure slide (not shown), which can be designed together with the closure element 52 designed as a rotating base. The design can be configured in particular such that the passage 28 to the receiving space 40 and the through-openings 58 for opening the lower channel opening 34 can be alternately opened and closed.

[0042] At its upper end, the compensation channel 32 opens into an upper channel opening 36, which emerges above a cover 42 laterally towards the central shaft 30, as clearly shown in Fig. 3 is shown.

[0043] The annular receiving space 40 in the housing 14 can be closed at the top by the plate-shaped cover 42, which can be held and stiffened by means of stiffening plates 43 at the upper end of the central shaft 30 or at the closure device 50.

[0044] During drilling, the receiving space 40 fills with removed soil material, which enters the receiving space 40 from the removal device 20 through the passage 28. After the receiving space 40 has been filled, the plate-shaped closure element 52, which can also be referred to as a rotating base, can be rotated relative to the folding base 51 by an opposite rotational movement, thereby closing the passage 28. At the same time, the closure element 52 can release the passage openings 58 in the cover 56 and thus the lower channel opening 34, so that the compensation channel 32 is open and extends from the lower region of the box drill 10 to the upper channel opening 36 above the cover 42.

[0045] The filled drilling tool can now be pulled vertically out of a borehole, with the closed closure device 50 ensuring that removed soil material from the receiving space 40 cannot fall back into the borehole. At the same time, the open compensation channel 32, which runs largely along the central shaft 30, ensures that no, or at most only a slight, negative pressure or pressure difference can develop between the underside of the drilling tool and the top side during pulling. This applies in particular when the outer diameter of the box drill 10 largely corresponds to the bore diameter. In this state, the drilling tool, designed as a box drill 10, can be pulled gently and quickly out of the borehole.

[0046] Outside the borehole, the box auger 10 can be emptied of soil material and then retracted into the borehole for a new drilling step. To empty the receiving chamber 40, a locking rod 62 of a locking device 60 at the upper end of the box auger 10 can be actuated, in particular pressed downward, whereby the folding bottom 51 is unlocked. Due to the force of gravity, the folding bottom 51, with the locking device 50 arranged thereon, can fold downward about the bolt-like pivot joint 54, so that the receiving chamber 40 is completely open at the bottom. Under the influence of gravity, the receiving chamber 40 can thus be emptied, with the removed soil material falling out downward.

[0047] Subsequently, the hinged base 51 can be closed again, for example, by pressing the box drill 10 onto the base. The hinged base 51 can then be locked again using the locking device 60, with the locking rod 62 being held in the locked position by a return spring 64. The box drill 10 can then be reinserted into the drill hole, and a new drilling step can be performed with the box drill 10.

Claims

1. Drill bucket for discontinuous earth drilling, comprising - a housing (14) comprising a receiving space (40), which is designed to receive the removed soil material, - a removal device (20), which is arranged below the housing (14) on a lower region of the drill bucket (10) and is designed for removing soil material, - at least one passage (28), which is designed for the removed soil material to pass through from the soil removal device (20) into the receiving space (40) during drilling, and - a closure device (50) for closing the at least one passage (28) when pulling the drill bucket (10) out of the borehole, characterised in that - a tubular central shaft (30) is arranged on the housing (14) and is designed as a compensation channel (32), which extends from at least one lower channel opening (34), which is arranged below or on the closure device (50), to at least one upper channel opening (36), which is arranged above the receiving space (40), wherein the compensation channel (32) is designed for a medium to flow through between the lower region and an upper region of the drill bucket (10) when the drill bucket (10) is pulled out and / or lowered into the borehole.

2. Drill bucket according to claim 1, characterised in that the lower channel opening (34) and / or the upper channel opening (36) can be closed.

3. Drill bucket according to claim 1 or 2, characterised in that the closure device (50) is designed to close the passage (28) to the receiving space (40) and also to close / open the lower channel opening (36).

4. Drill bucket according to any one of claims 1 to 3, characterised in that the closure device (50) comprises a closure element (52), which is adjustable between a closed position, in which the passage (28) to the receiving space (40) is closed by the closure element (52), and a drilling position, in which the passage (28) is open during drilling for soil material to pass through into the receiving space (40).

5. Drill bucket according to claim 4, characterised in that the lower channel opening (36) is closed in the drilling position of the closure element (52) and the lower channel opening (34) is open in the closed position of the closure element (52).

6. Drill bucket according to claim 4 or 5, characterised in that the closure element (52) is designed as a revolving base, which is rotatable between the closed position and the drilling position.

7. Drill bucket according to any one of claims 1 to 6, characterised in that a cover (42), in particular a cover plate, is arranged on an upper region of the housing (14), and closes the receiving space (40) at the top and separates it from the upper channel opening (36).

8. Drill bucket according to any one of claims 1 to 7, characterised in that a hinged base (51) is arranged on a lower region of the housing (14), and closes the receiving space (40) at the bottom and can be moved between a drilling position, in which the hinged base (51) is locked in a receiving position, and an emptying position, in which the hinged base (51) is unlocked and is opened to empty the receiving space (40).

9. Drill bucket according to any one of claims 1 to 8, characterised in that the receiving space (40) is annular, wherein the housing (14) comprises an outer circumferential wall (16) and an inner circumferential wall, which is formed by the central shaft (30).

10. Drill bucket according to any one of claims 1 to 8, characterised in that a cover hood (56) is arranged on the lower channel opening (34) and is provided with lateral passage openings (58).

11. Drilling implement, which comprises a carrier unit, which comprises a chassis, in particular a track-mounted chassis, and a superstructure rotatably mounted thereon, characterised in that a drill bucket (10) according to any one of claims 1 to 10 is arranged.

12. Method for making a bore in the ground, in particular for discontinuous drilling, characterised in that a drill bucket (10) according to any one of claims 1 to 10 or a drilling implement according to claim 11 is used, and in that, for removing soil material during drilling, the passage (28) to the receiving space (40) is opened and the lower channel opening (34) is closed.

13. Method according to claim 12, characterised in that, for pulling out the drill bucket (10), the passage (28) to the receiving space (40) is closed and the lower and / or upper channel opening (34) is opened.

14. Method according to any one of claims 12 or 13, characterised in that the compensation channel (32) is opened for lowering the drill bucket (10) into the borehole.

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