Drilling rig for creating essentially horizontal boreholes in the ground

Abstract

Drilling rig for producing substantially horizontal boreholes, comprising a drill string (17), a drill carriage (14) receiving the drill string (17), and a drive (16A) associated with the drill carriage (14) for generating a feed force exerted on the drill string (17), wherein the drive (16A) is operatively connected to the drill string (17) via a spring accumulator and / or buffer (44) acting in the axial direction (48) of the drill string (17), characterized in that the spring accumulator and / or buffer (44) has at least two pairs of helical compression springs (45) arranged parallel and symmetrically next to or behind the drill string (17), each of which is penetrated by a guide rod (46) and which are connected to the drill string or to a thrust bearing associated with the drill string at its rear end via a thrust bearing that at least partially encompasses the drill string and can be fixed axially to it. Attack the rod end piece,wherein the helical compression springs (45) are pre-tensioned on the guide rod (46) by means of an adjustable abutment, and wherein a force measuring device (49) for determining the spring force is assigned to the spring accumulator and / or buffer (44), wherein a drive control or regulation for the drive (16A) acted upon by the force measuring device (49) is provided for automatic adjustment of the feed rate depending on the determined spring force.

Description

[0001] The invention relates to a drilling device for producing, in particular, substantially horizontally extending earth boreholes, comprising a drill rod, a drill carriage receiving the drill rod, and a drive associated with the drill carriage for generating a feed force exerted on the drill rod, wherein the drive is operatively connected to the rod via a spring accumulator and / or buffer acting in the axial direction of the drill rod.

[0002] DE 195 28 620 A1 discloses a device for creating a borehole using a drill rod inserted into the ground, which is provided with a drill bit or similar tool at its front end. In such devices, the drill rod is usually rotated by a hydraulic rotary drive and advanced by a hydraulic feed drive. The borehole is often created using the flush drilling method, in which a flushing fluid is pumped into the interior of the drill rod to the drill bit, where it assists in loosening the soil and transports it back through the created borehole.

[0003] When drilling through the ground to create an earth bore, the drill bit of the drill string does not usually encounter a homogeneous material, but rather soft and hard components alternate in an unpredictable manner. The feed forces required to advance the earth auger are therefore not constant. Rather, it often happens that, for example, when drilling through a generally soft, easily penetrated material, which can generally be done at a relatively high feed rate, the drill bit unexpectedly encounters a large stone or similar object and thus encounters a sudden increase in resistance. This leads to a correspondingly sudden increase in the longitudinal force in the drill string counteracting the feed. This sudden load then reverberates through to the feed drive of the drilling rig, representing a high mechanical stress.

[0004] In order to better protect the feed drive of the drilling rig against such loads, the drive is operatively connected to the rod via a spring accumulator and / or buffer acting in the axial direction of the drill rod, as is known from DE 21 23 898 A or DE 199 17 538 A1.

[0005] This decouples the feed drive from the drill rod via the spring-loaded actuator or buffer, so that sudden loads, which act through the drill rod back onto the drilling rig as a result of the drill bit hitting an obstacle in the ground, are not immediately and abruptly transmitted to the drive. Instead, the resulting shocks are initially absorbed in the form of spring energy by the spring element(s) provided in the spring-loaded actuator / buffer. This better protects the feed drive from these loads. Furthermore, the arrangement ensures that the feed movement generated by the drive, which initially runs at a mostly constant, preset speed, is automatically adjusted to the current condition of the soil being drilled through.If the drill bit encounters a hard obstacle in otherwise soft soil, which naturally cannot be drilled through as quickly as, for example, clay or sandy soil, the higher resistance in the spring accumulator causes its spring element(s) to be tensioned and accordingly increases the longitudinal feed force in the rod, so that the stone or similar is crushed better and faster.

[0006] To further improve a generic device, the invention provides that the spring accumulator and / or buffer has at least two helical compression springs arranged in pairs parallel and symmetrically next to or behind the drill rod, each of which is penetrated by a guide rod and which act on the drill rod or a rod end piece assigned to the rear end thereof via a thrust bearing which at least partially surrounds the drill rod and can be axially fixed thereto, wherein the helical compression springs are pre-tensioned on the guide rod by means of an adjustable abutment, and that a force measuring device for determining the spring force is assigned to the spring accumulator and / or buffer, wherein a drive control or regulation acted upon by the force measuring device is provided for the drive as a function of the determined spring force for automatically adjusting the feed rate.If the force measuring device detects a sudden increase in spring force, this indicates a correspondingly increased resistance during the advance of the drill rod and thus an obstacle in the drilling path. Using the drive control or regulation for the drive provided by the force measuring device, depending on the determined spring force, the feed rate is automatically adjusted if the drilling resistance changes, for example, if an obstacle is encountered.

[0007] By arranging at least two compression springs a arranged in pairs parallel and symmetrically next to the drill rod, which engage the drill rod or a rod end piece assigned to the rear end of the drill rod via a thrust bearing which at least partially surrounds the drill rod and can be fixed axially thereto, a largely bending moment-free force transmission between the drill rod and the spring accumulator / buffer is ensured in a simple manner.

[0008] Since the compression springs of the spring actuator and / or buffer are helical compression springs, each of which is traversed by a guide rod, this effectively prevents the springs from buckling laterally, even if they are subjected to an off-center longitudinal load. The arrangement is such that the helical compression springs are preloaded on the guide rods by means of an adjustable abutment.

[0009] In practice, it has proven particularly reliable if the spring accumulator and / or buffer can be actuated by means of a rack and pinion gear operated by the drive.

[0010] The drive for the drill rod expediently comprises, in a conventional manner, at least one feed drive for generating the feed and a rotary drive for generating a rotary movement acting on the drilling tool. The arrangement is preferably such that the spring accumulator and / or buffer is located between the feed drive and the rotary drive, so that the torque generated by the rotary drive acting on the rod does not lead to otherwise possible transverse forces on the spring elements of the spring accumulator / buffer.

[0011] In an advantageous embodiment of the invention, the drive for the drill rod can be arranged on the drill carriage, in particular in a rear area thereof. The drill carriage is preferably arranged on a carriage carrier, in particular a mobile carriage carrier, in a height- and angle-adjustable manner. The design is also preferably such that the thrust bearing arranged on the drill rod or another point of engagement for the spring accumulator and / or buffer can be fixed in various positions on the drill rod. It has proven to be a particularly advantageous design if the rotary drive is arranged on a feed carriage that is displaceable along a guide arranged on the drill carriage, in which case the spring accumulator and / or buffer can be arranged between the feed carriage and a rack and pinion of the rack and pinion gear, which is also displaceable along the guide.

[0012] Further features and advantages of the invention will become apparent from the following description and the drawing, in which a preferred embodiment of the invention is illustrated in more detail by way of example. It shows: Fig. 1 an earth drilling device with a drilling device according to the invention in a schematic, simplified representation in a side view with the drilling carriage in the rest position; Fig. 2 the subject of Fig. 1 in working condition in position at a starting pit of the ground borehole to be produced; Fig. 3 the device of Fig. 1 and Fig. 2 in a simplified plan view; and Fig. 4 the rear area of ​​the drilling rig in the area of ​​its drive with the spring accumulator and / or buffer provided according to the invention in a schematically simplified side view.

[0013] The earth drilling device, designated 10 in the drawing, is a particularly compact device that can be used to create essentially horizontal earth bores even in confined spaces, such as in inner-city areas. The machine is particularly suitable for applications where it is necessary or desirable to create access to a building's basement foundation without extensive civil engineering work, e.g., to install a new service connection for a water or gas line, an electrical cable, or a fiber optic connection.

[0014] The drilling device 10 has a chassis 11 equipped with two crawler tracks 12 that define the chassis 11 on the right and left sides of the device 10. The crawler tracks allow the device to be moved and brought precisely to a location.

[0015] A drilling rig 13 according to the invention is arranged on the chassis 11, with which boreholes can be drilled in the ground, as is known. The drilling rig 13 has a drilling carriage 14 that is adjustable in height and angle relative to the chassis 11. At its rear end 15, a hydraulic rotary and feed drive 16 is arranged, which can drive a drill rod 17 in a known manner, with which the desired borehole is created. The drilling rig 13 is advantageously a flush drilling device, with which a flushing fluid introduced through the drill rod emerges at the front end of the rod at the drill head formed there and causes the loosened soil to be loosened and transported away, as is usual in flush drilling methods.The drive 16 for the rotation of the drill rod and its advance is carried out hydraulically with a hydraulic medium which is supplied to the drive via hydraulic lines from a separate hydraulic station not shown in detail in the drawing, similarly to the flushing fluid for the hydraulic loosening and / or flushing of the soil is prepared by a mixing system arranged separately from the device 10 and supplied to the device by means of pumps.

[0016] The device 10 is characterized by a compact design, which allows for use even in confined spaces. This is essentially achieved by arranging the drilling carriage 14 on the chassis 11 in such a way that its front end 20, pointing toward a penetration point 18 of the borehole 19, can be lowered laterally next to the left- or right-side chassis 12, or between these two in the illustrated embodiment. As can be seen in particular from Fig. 2, this particularly advantageous design allows the distance between the front, lowered end 20 of the drilling carriage 14 and the insertion point 18 to be shortened to a very small extent in the horizontal direction, and it is possible to place the chassis 11 of the device 10 at a correspondingly short distance in front of an existing boundary, for example in front of a property fence 21. The device according to the invention is therefore particularly suitable for use in confined spaces, for example on a sidewalk 22 in front of the front garden of a building (not shown), without obstructing the traffic on the adjacent road surface 23.

[0017] How to use the Fig. 2 and Fig. 3, the chassis 11 has a support structure 24 for the drilling device 13, which extends between the carriages 12 and has a pivot joint 25, about which the drilling carriage can be pivoted and lowered with its front end 20. The support structure 24 is provided on the front side 26 facing the penetration point 18 of the earth bore 19 with a recess 27 formed between the carriages, which is open downwards towards the installation surface 28 on which the device 10 is placed for its use. With this arrangement, the front end 20 of the carriage 14 can be lowered into this recess 27 when pivoting about the pivot joint 25. The front end 20 of the drilling carriage is thus in the Fig. 2, the drill rig does not extend, or at least not significantly, in front of the front 26 of the support structure 24 or the chassis 11 of the device. The front section of the drill rig, which is lowered, is then located between the two crawler tracks 12, and the total installation space occupied by the device during operation is not, or at least not significantly, larger than the area occupied by the chassis with the two crawler tracks.

[0018] To move the drill carriage 14 into its Fig. 2, a hydraulic cylinder 29 is arranged horizontally on the rear part of the support structure 24, which is supported on the cylinder side in the area of ​​the pivot joint 25. With its piston rod, the hydraulic cylinder 29 acts on a longitudinally displaceably mounted bearing block 30, to which a support 31 is pivotally connected at a first end. The other end of the support 31 is pivotally mounted on the rear end 15 of the carriage 14. In order to move the carriage from the Fig. 1 shown rest position into the Fig. To set up the carriage in the working position shown in Figure 2, the hydraulic cylinder 29 is actuated, so that the extending piston rod moves the bearing block 30 rearward on the support structure 24, thereby erecting the support 31. This raises the rear end 15 of the carriage and pivots it about the pivot joint 25, so that the front end 20 of the carriage is lowered into the recess 27 between the two chassis.

[0019] At the front end 20 of the drilling carriage 14, the latter is provided on its underside with a replaceable abutment element 32, which in the illustrated embodiment consists of a steel angle. This has a first, substantially vertical leg and a horizontal leg running at a right angle thereto, wherein the arrangement here is such that the steel angle is open towards the rear end of the chassis. The abutment element 32 serves to support the device in the horizontal direction during operation when creating the horizontal bore. In the illustrated embodiment, in which according to Fig. 2 If the penetration point 18 of the earth bore 19 is located in a front side 33 of a launch pit 34, the horizontal leg of the abutment element rests on the rear edge 35 of the pit 34, while the vertical leg of the abutment element 32 rests on the rear side 36 of the launch pit and absorbs the longitudinal forces resulting from the drilling process and acting in the drill rod 17. In this way, the horizontal component of the reaction forces resulting from the drilling process is at least partially deposited in the soil bordering the launch pit, so that these reaction forces do not have to be dissipated into the subsoil exclusively via the device's undercarriages.

[0020] Fig.Figure 4 shows, in a schematically simplified side view, the drilling rig 13 designed according to the invention in the drive area at the rear end 15 of the drilling carriage 14. As can best be seen there, the drive 16 comprises a feed drive 16A and a rotary drive 16B for the drill rod 17. The rotary drive 16B is fixedly arranged on a feed carriage 38, which is mounted for longitudinal displacement on a guide 39 formed on the top of the drilling carriage 14. The feed drive 16A comprises a gear motor 40 fixedly suspended on the carriage 14 and having a drive gear 40A, which forms a rack and pinion gear with a rack and pinion gear 41. The rack 41 is also guided longitudinally displaceably on the guide 39 and is moved by actuation of the gear motor 40 by its drive gear 40A in the direction of the feed carriage 38 with the rotary drive 16B arranged thereon.

[0021] At the front end of the rack and pinion 41, it is provided with a bracket 42 at a distance from the rear side 43 of the feed carriage 38.

[0022] Between the console 42 and the rear side 43 of the slide 38 there is arranged a spring accumulator / buffer 44 which has at least two helical compression springs 45 arranged one above the other in pairs and guide rods 46 for the springs 45 which are fastened to the console by their rear ends and can be inserted by their front ends into rod guides 47 in the slide 38 on the rear side 43 thereof.

[0023] The feed drive 16A is thus operatively connected via the spring-loaded mechanism 44 acting in the axial direction 48 of the drill rod 17, indirectly via the feed carriage 38 and the rotary drive 16B arranged thereon. When the feed drive 16A is actuated and, via its drive gear 40, displaces the rack and pinion 41 forward in the longitudinal direction 48 toward the front end 20 of the carriage 14, this drive movement is transmitted to the carriage via the springs 45 of the spring-loaded mechanism. Depending on the drilling resistance in the longitudinal direction of the rod, the springs are tensioned more or less. The more the springs are compressed, the greater the longitudinal feed force acting along the drill rod onto the drill bit mounted at its front end.Since the spring accumulator / buffer can buffer the movement exerted by the feed drive, i.e. this is not transferred 1:1 to the drill rod as a forced movement, but pressure peaks are absorbed by storing their energy in the springs, the load acting on the rod is evened out and the service life of the drilling equipment, in particular of its drill rod and drill bit, is improved.

[0024] In the exemplary embodiment, the lower of the two coil springs 45 shown rests on the rear of the bracket 42 via a load cell 49. The load cell can be used to determine the effective spring force. The load cell is connected to the feed motor 16A via a control line 50 and control electronics (not shown / designated in detail), so that its signal can be used to control / regulate the drive. In particular, this can be used to implement an automatically triggered overload circuit that shuts down the feed as soon as the spring force in the coil springs exceeds a preset value.

Claims

[1] Drilling device for producing essentially horizontally extending earth boreholes, comprising a drill rod (17), a drill carriage (14) receiving the drill rod (17) and a drive (16A) associated with the drill carriage (14) for generating a feed force exerted on the drill rod (17), wherein the drive (16A) is operatively connected to the rod (17) via a spring accumulator and / or buffer (44) acting in the axial direction (48) of the drill rod (17), characterized bythat the spring accumulator and / or buffer (44) has at least two helical compression springs (45) arranged in pairs parallel and symmetrically next to or behind the drill rod (17), each of which is penetrated by a guide rod (46) and which act on the drill rod or a rod end piece assigned to the rear end thereof via a thrust bearing which at least partially surrounds the drill rod and can be fixed axially thereto, wherein the helical compression springs (45) are arranged on the guide rod (46) in a pre-tensioned manner by means of an adjustable abutment, and that a force measuring device (49) for determining the spring force is assigned to the spring accumulator and / or buffer (44), wherein a drive control or regulation acted upon by the force measuring device (49) is provided for the drive (16A) as a function of the determined spring force for automatically adjusting the feed rate. [2] Drilling device according to claim 1, characterized bythat the spring accumulator and / or buffer (44) can be acted upon by means of a rack and pinion gear (40A, 41) actuated by the drive (16A). [3] Drilling device according to claim 1 or 2, characterized by that the drive (16) comprises at least one feed drive (16A) for generating the feed and a rotary drive (16B) for generating a rotary movement effective on a drilling tool. [4] Drilling device according to claim 3, characterized by that the spring accumulator and / or buffer (44) is arranged between the feed drive (16A) and the rotary drive (16B). [5] Drilling device according to claim 3 or 4, characterized bythat the rotary drive (16B) is arranged on a feed carriage (38) which is displaceable along a guide (39) arranged on the drilling carriage (14), and that the spring accumulator and / or buffer (44) is arranged between the feed carriage (38) and a rack and pinion (41) of the rack and pinion gear (40A, 41) which is also displaceable along the guide. [6] Drilling device according to one of claims 1 to 5, characterized by that the drive (16) for the drill rod (17) is arranged on the drill carriage (14), in particular in a rear area (15) thereof. [7] Drilling device according to one of claims 1 to 6, characterized by that the drilling carriage (14) is arranged on a carriage carrier (11), in particular a mobile carriage carrier, in a height- and angle-adjustable manner. [8] Drilling device according to one of claims 1 to 7, characterized bythat the thrust bearing arranged on the drill rod (17) or another point of engagement (38) for the spring accumulator and / or buffer (44) can be fixed in different positions on the drill rod (17).

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