Device for connecting a drilling tool to the power rotary head of a drilling machine

Abstract

Device for connecting a tubular drilling tool to the rotary power head of a drilling rig, comprising a connecting tube and at least two radially arranged locking bolts (33) guided through the connecting tube, which engage in a corresponding opening of a drilling tool, wherein at least two hydraulic cylinders (31) are arranged, by means of which the at least two locking bolts (33) are movable, wherein pumping means are arranged, by means of which the at least two hydraulic cylinders (31) can be operated, wherein the pumping means are connected to a piston accumulator (4), to which the at least two hydraulic cylinders (31) are connected, wherein a push rod (42) is arranged, which can be actuated by inserting a drilling tool (6) to be received into the connecting tube (1), wherein each of the at least two locking bolts (33) is connected to the hydraulic cylinder (31) via a rocker arm (32).which is pre-tensioned in the closed position of the locking bolt (33) via a spring element, which spring element is formed by a disc spring assembly integrated into the hydraulic cylinder (31), by which a piston (311) of the hydraulic cylinder (31) connected to the rocker arm is pre-tensioned such that the locking bolt (33) is pre-tensioned through the wall of the connecting pipe (1) in the direction of its central axis, characterized in that the pumping means comprise an electric hydraulic pump (44) by which the piston accumulator (4) is pressurized with hydraulic pressure, wherein the push rod (42) is connected to a sensor device which, when the push rod (42) is actuated, sends an actuation signal to a hydraulic switching valve (5) upstream of the hydraulic cylinders (31), which is switched in such a way thatthat in the rest position of the push rod (42) the locking bolts (33) are in the open position and when an actuation signal is applied the hydraulic cylinders (31) are disconnected from the piston accumulator, whereby the locking bolts (33) are in the locked position by the spring preload.

Description

[0001] The invention relates to a device for connecting a tubular drilling tool to the power rotary head of a drilling device according to the preamble of claim 1.

[0002] When drilling deeper boreholes, they are regularly lined with casing to prevent soil from collapsing. As the borehole deepens, the casing must be extended accordingly. This is achieved by joining individual casings together, and the resulting drill string is then pushed into the ground. To facilitate this movement, the entire drill string is rotated using the rotary head of a drilling rig.

[0003] The connection point between the drilling rig's rotary head and the newly inserted drill pipe is located up to 6 meters above ground level. For manual connection, one person must climb a ladder to the connection point and insert the necessary connecting bolts. Alternatively, this can be done using a telescopic pole from the drilling rig's base. Since the drill pipes typically have a diameter of 600 to 2000 mm, the ladder must be repositioned several times to insert each connecting bolt. Establishing the mechanical connection between the drill pipe and the rotary head's connecting pipe is therefore time-consuming and dangerous. After drilling is complete, the drill string is pulled out of the borehole by rotating and pulling the rotary head.Once a drill pipe is completely above ground level, it is disconnected from the section of the string below. The connection between the end of the drill pipe and the connecting pipe of the drilling rig's rotary head must then be disconnected again at a considerable height in the same manner.

[0004] To address this problem, CH 675747 A5 proposes automating the establishment and release of the mechanical connection between the upper end of the drill pipe and the connecting pipe of the rotary power head using a remotely actuated locking coupling between the connecting pipe and the upper end of the drill pipe. The locking coupling comprises coupling pins that can be inserted into aligned holes at the lower end of the connecting pipe or the upper end of the drill pipe by a servo drive. The servo drive is formed either by an actuating ring connected via a pinion drive or by hydraulic cylinders whose piston rod ends form the coupling pins. However, this solution is very complex. Furthermore, the supply of pneumatic or hydraulic fluids via rotary unions often proves prone to malfunctions and leakage.

[0005] Against this background, EP 3 163 009 A1 teaches a device for connecting a tubular drilling tool to the rotary power head of a drilling rig, comprising a connecting tube and at least two radially arranged locking bolts that engage in a corresponding opening in the drilling tool. The device incorporates two actuators formed by a hydraulic cylinder, which allow the at least two locking bolts to be moved. The hydraulic cylinders are operated by a pump cylinder, which is driven by a push rod through the insertion of the drilling tool into the connecting tool. Each locking bolt is connected to the hydraulic cylinder via a rocker arm, which is pre-tensioned in the closed position of the locking bolt by a spring element.The spring element pre-tensions a piston of the hydraulic cylinder connected to the swing arm in such a way that, in the rest state, the locking bolt is pressed through the wall of the connecting pipe in the direction of its central axis.

[0006] This solution has proven very effective in practice. However, an area for improvement has been identified: when inserting a drill bit into the connecting tool, a significant insertion force is required to operate the pump cylinder via the push rod and to move the pre-tensioned locking bolts outwards against the spring force before they engage in the corresponding opening of the drill bit.

[0007] This is where the present invention comes in. The invention is based on the objective of further developing the proven device for connecting a tubular drilling tool to the rotary power head of a drilling machine in such a way that the insertion force required to insert a drilling tool into the connecting tool is reduced. According to the invention, this objective is achieved by a device with the features of the characterizing part of claim 1.

[0008] The invention provides a device for connecting a tubular drilling tool to the rotary power head of a drilling device of the aforementioned type, in which the required insertion force for inserting a drilling tool to be received into the connecting tool is reduced.Because the pumping means include an electric hydraulic pump that pressurizes the accumulator with hydraulic pressure, and the push rod is connected to a sensor device that, when the push rod is actuated, sends an actuation signal to a hydraulic switching valve upstream of the hydraulic cylinders, which is switched such that in the rest position of the push rod the locking bolts are in the open position and when an actuation signal is applied the hydraulic cylinders are disconnected from the accumulator, whereby the locking bolts are in the locked position by the spring preload, an additional insertion force to drive a pump piston to supply the accumulator with hydraulic pressure and to laterally displace locking bolts in the closed position against the spring preload is no longer required.In addition, the positioning accuracy required for inserting the drilling tool into the connecting tool is reduced in order to prevent tilting against the locking bolts.

[0009] In a further development of the invention, the push rod is pre-tensioned in its rest position by a compression spring. This prevents unintentional actuation of the push rod. It is thus only actuated when the drill bit is inserted into the connecting tool.

[0010] In one embodiment of the invention, the sensor device comprises an inductive sensor for monitoring the position of the push rod. This ensures reliable and robust detection of the push rod's actuation.

[0011] In a further embodiment of the invention, a battery is arranged, which powers the electric hydraulic pump. Preferably, the battery is a lithium-ion battery.

[0012] In a further development of the invention, a pressure sensor is arranged which continuously monitors the pressure in the piston accumulator and is connected to the hydraulic pump to regulate a preset overpressure in the piston accumulator. This ensures automatic restoration of the overpressure after actuation of the switching valve. A pressure control module is located upstream of or integrated into the switching valve for pressure regulation. Preferably, the pressure sensor is integrated into the switching valve.

[0013] In this embodiment of the invention, the at least two locking bolts are conically shaped at their end facing away from the rocker arm. This facilitates the insertion of the respective locking bolt into the respective opening of the drilling tool.

[0014] In a further embodiment of the invention, the locking bolt has an angled centering edge at its end facing away from the swing arm. This facilitates the smooth sliding of the locking bolt into the locked position. Preferably, the centering edge is angled at 5° to 15°, and more preferably at 10°, to the end face of the locking bolt.

[0015] Other embodiments and configurations of the invention are specified in the remaining dependent claims. Exemplary embodiments of the invention are illustrated in the drawings and are described in detail below. The drawings show: Fig. 1 the schematic representation of a device for connecting a tubular drilling tool to the power rotary head of a drilling machine; Fig. 2 the representation of the connecting pipe of the device Fig. 1; Fig. 3 the detailed representation of the push rod arrangement of the connecting pipe from Fig. 2 a) before picking up a drilling tool; b) after half of the drilling tool has been inserted and c) after the drilling tool has been picked up; Fig. 4 the detailed illustration of the locking bolt arrangement from Fig. 3 a); Fig. 5 the schematic detail representation of the locking bolt of the locking arrangement from Fig. 5 a) in a first side view; b) in a second side view.

[0016] In Fig. Figure 1 shows a device according to the invention on the rotary power head 2 of a drilling rig. The device comprises a connecting tube 1 provided with an end plate 13, which is connected via a tab 11 arranged on the end plate 13 to a universal joint 21 arranged on the rotary power head 2. The connecting tube 1 transmits compressive and tensile forces as well as the torque of the rotary power head 2 to a received drill pipe 6. At least two locking devices 3 are arranged diametrically opposite each other on the connecting tube 1 at its end opposite the tab 11. The locking devices 3 each comprise a hydraulic cylinder 31, which is connected via a rocker arm 32 to a locking bolt 33, which is slidably mounted in a through-hole 12 of the connecting tube 1.The hydraulic cylinder 31 incorporates a disc spring assembly (not shown) which preloads the piston 311 connected to the rocker arm 32 in such a way that the locking bolt 33 is pressed through the wall of the connecting tube 1 in the direction of its central axis.

[0017] The piston 31 is connected to a piston accumulator 4 via a hydraulic line (not shown). In the exemplary embodiment, the gas side of the piston accumulator 4 is filled with nitrogen. The piston accumulator 4 is in turn connected via a line (not shown) to an electric hydraulic pump 44, which is powered by a lithium-ion battery (not shown). The electric hydraulic pump 44, which in the exemplary embodiment has an integrated hydraulic tank, serves to pressurize the piston accumulator 4 with hydraulic oil.

[0018] A push rod 42 is slidably mounted on the connecting pipe and biased in the opposite direction to the cardan joint 21 by a compression spring 45. At its end, the push rod 42 is provided with a push claw 43, which projects into the connecting pipe 1 through an opening 17. A switching valve 5, connected to a sensor 41, is arranged between the piston accumulator 4 and the hydraulic cylinders 31 of the locking devices 3. The sensor 41, which in this embodiment is designed as an inductive sensor, is positioned axially spaced from the push rod 42 and detects the displacement of the push rod 42 when it is actuated.

[0019] The locking device 3 is in Fig. Figure 4 shows in detail. As can be seen there, the piston 311 of the hydraulic cylinder 31 is connected to the rocker arm 32, which is pivotally mounted via a rocker arm bearing 36 and is connected at its end opposite the piston 311 to the locking bolt 33. The locking bolt 33 is slidably guided in the passage 12 of the connecting pipe 1, which for this purpose is designed in the form of an outwardly projecting sleeve.

[0020] The locking bolt 33 is in Fig. Figure 5 shows in detail. The locking bolt 33 is essentially cylindrical and has at its end facing the rocker arm 32 a substantially cuboid connecting piece 35, which is provided with a through-hole 351 for connection to the rocker arm 32. At its end opposite the rocker arm 32, the locking bolt 33 is tapered and provided with a centering edge 34, which is angled to the end face of the locking bolt 33. In the exemplary embodiment, the centering edge 34 has an angle of 10° to the end face of the locking bolt 33.

[0021] The two locking devices 3 arranged on the connecting pipe 1 are protected to the outside by a cover 7, which is pivotably connected to the connecting pipe 1 at a distance from it.

[0022] To connect a drill pipe 6 to the connecting pipe 1 arranged on the rotary power head 2, the drill pipe 6 is inserted into the connecting pipe 1 until the end-reduced diameter section 63 of the drill pipe 6 is completely enclosed by the connecting pipe 1, so that the latter rests against the shoulder 61 of the drill pipe 6 formed by the reduced diameter section 63. The switching valve 5 is connected in a conducting manner, whereby the locking bolts 3 are held in the open position against the spring preload (see Figure 1). Fig. 4).

[0023] When the drill pipe 6 is inserted into the connecting pipe 1, the diameter-reduced end section 63 of the drill pipe 6 is received by the push claw 43 of the push rod 42, which projects through the opening 17 into the connecting pipe 1 and is moved upwards by the drill pipe 6 in the direction of the tab 11 of the connecting pipe 1.

[0024] In the final position of the drill pipe 6, where the shoulder 61 rests against the connecting pipe 1, the push rod 42 has reached its actuated position against the preload of the compression spring 45, which is detected by the sensor 41. The sensor signal switches the switching valve 5 to the closed position.

[0025] This disconnects the hydraulic cylinders 31 from the piston accumulator 4. The hydraulic oil contained in the hydraulic cylinders 31 flows into the hydraulic tank of the electric hydraulic pump 44. The conical ends of the pre-tensioned locking bolts 33 slide along the passage 12 of the connecting pipe 1 through the connecting pipe 1 into the connecting bores 62 of the drill pipe 61, which are aligned with the passages 12, thereby positively connecting the drill pipe 6 to the connecting pipe 1.

[0026] To release the connection between the drill pipe 6 and the connecting pipe 1, the switching valve 5, which is connected to the radio control 51, can be actuated remotely. The hydraulic oil overpressure previously built up in the piston accumulator 4 by the electric hydraulic pump 44 now re-actuates the hydraulic cylinders 31 of the locking devices 3, thereby moving the locking bolts 33 out of the connecting bores 62 of the drill pipe 6 against their preload. The drill pipe 6 can now be pulled out of the connecting pipe 1, whereby the push rod 42 is returned to its rest position by the preload of the compression spring 45.

[0027] The switching valve 5 includes an integrated pressure sensor 8, which continuously monitors the pressure state of the accumulator 4. The pressure drop resulting from the actuation of the switching valve 5 is detected by the pressure sensor 8, thereby activating the electric hydraulic pump 44, which refills the pressure in the accumulator 4. Once the preset pressure in the accumulator 4 is reached again, this is detected by the pressure sensor 8 and the electric hydraulic pump 44 is deactivated.

[0028] The device according to the invention is characterized in particular by the fact that the locking bolts 33 are pre-tensioned in the closed position by spring assemblies in their rest position and are held in the open position against the spring pre-tension by the hydraulic system. Locking is effected by separating the hydraulic cylinders 31 from the piston accumulator 4 by moving the locking bolts 33 via the spring pre-tension of the spring assemblies.

[0029] The separation is effected via the switching valve 5, controlled by a sensor 41, which detects an actuation of the push rod 42 by the insertion of the drill pipe 6 into a connecting pipe.

Claims

[1] Device for connecting a tubular drilling tool to the rotary power head of a drilling rig, comprising a connecting tube and at least two radially arranged locking bolts (33) guided through the connecting tube, which engage in a corresponding opening of a drilling tool, wherein at least two hydraulic cylinders (31) are arranged, by means of which the at least two locking bolts (33) are movable, wherein pumping means are arranged, by means of which the at least two hydraulic cylinders (31) can be operated, wherein the pumping means are connected to a piston accumulator (4), to which the at least two hydraulic cylinders (31) are connected, wherein a push rod (42) is arranged, which can be actuated by inserting a drilling tool (6) to be received into the connecting tube (1), wherein each of the at least two locking bolts (33) is connected to the hydraulic cylinder (31) via a rocker arm (32),which is pre-tensioned in the closed position of the locking bolt (33) via a spring element, which spring element is formed by a disc spring assembly integrated into the hydraulic cylinder (31), by which a piston (311) of the hydraulic cylinder (31) connected to the rocker arm is pre-tensioned such that the locking bolt (33) is pre-tensioned through the wall of the connecting tube (1) in the direction of its central axis, characterized by, that the pumping means comprise an electric hydraulic pump (44) by which the piston accumulator (4) is pressurized with hydraulic pressure, wherein the push rod (42) is connected to a sensor device which, when the push rod (42) is actuated, sends an actuation signal to a hydraulic switching valve (5) upstream of the hydraulic cylinders (31), which is switched such that, in the rest position of the push rod (42), the locking bolts (33) are in the open position and, when an actuation signal is applied, the hydraulic cylinders (31) are disconnected from the piston accumulator, whereby the locking bolts (33) are in the locking position by the spring preload. [2] Device according to claim 1, characterized by , that the push rod (42) is pre-tensioned in the rest position by means of a compression spring (45). [3] Device according to claim 1 or 2, characterized by, that the sensor device includes an inductive sensor (41) for monitoring the position of the push rod (42). [4] Device according to one of the preceding claims, characterized by , that an accumulator is arranged, via which the electric hydraulic pump (44) is operated. [5] Device according to any of the preceding claims, characterized by , that a pressure sensor (8) is arranged which continuously monitors the pressure in the piston accumulator (4) and which is connected to the hydraulic pump (44) to control a preset overpressure in the piston accumulator (4). [6] Device according to claim 5, characterized by , that the pressure sensor is integrated into the switching valve (5). [7] Device according to one of the preceding claims, characterized by , that the at least two locking bolts (33) are conically shaped at their end facing away from the swing arm (32). [8] Device according to claim 7, characterized by, that the locking bolts (33) have an angled centering edge (34) at their end facing away from the swing arm (32). [9] Device according to claim 8, characterized by , that the centering edge (34) is set at an angle of 5° to 15°, preferably at an angle of 10° to the end face of the locking bolt (33).

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