A two-jaw iron roughneck for mechanically centering tubing drill pipes

Abstract

The present invention discloses a two-jaw iron roughneck capable of mechanically centering oil pipe drill pipes. It includes a telescopic robotic arm, a clamping device, and a mechanical centering mechanism; the clamping device is fixed at the free end of the telescopic robotic arm, enabling the robotic arm to drive the clamping device to move; the mechanical centering mechanism is fixed above the clamping device for guiding the movement of the telescopic robotic arm; the clamping device includes a two-stage speed-changing gear set, a hydraulic clamping system, a housing, and a cycloidal motor; the two-stage speed-changing gear set and the hydraulic clamping system are cooperatively installed in the housing, the body of the cycloidal motor is fixed on the housing and the output shaft passes through the housing and is synchronously connected to the two-stage speed-changing gear set; a notch is machined at one end of the housing, and the operating object is vertically arranged in the notch of the housing, and both the mechanical centering mechanism and the clamping device are in contact connection with the operating object through the notch of the housing. The present invention can adapt to all sizes of oil pipe drill pipes, and can realize the make-up and break-out of the oil pipe drill pipes only with the upper and lower two jaws, with a compact structure, reliable functions, and strong practicability.

Description

Technical Field

[0001] The invention relates to a two-clamp iron roughneck in the field of oil drilling, in particular to a two-clamp iron roughneck capable of mechanically centering an oil pipe drill rod. Background Art

[0002] Iron roughneck equipment is an automated tool that can be used at the wellhead of an oil well. It is widely used for loading and unloading oil pipes during drilling and well repair operations on land and sea. The iron roughneck tongs head can be telescopically moved under the action of the mechanical arm. Compared with the hydraulic power tongs used for wellhead operations in the past, it is more flexible and maneuverable, greatly improving production efficiency, greatly saving human resources, and increasing safety, avoiding the operational risks that workers need to bear when operating hydraulic power tongs.

[0003] At present, the tongs of iron roughnecks are composed of the main tongs at the bottom, i.e. the buckle tongs, the backup tongs in the middle, and the rotating tongs at the top. The main tongs are used for buckle, with low speed, high torque and small angular travel; the backup tongs do not rotate, but only have the clamping function, clamping the clamp part at one end of the tubing to withstand the reverse torque of the buckle; the rotating tongs are used for buckle, clamping the tubing body and driving the tubing to rotate at high speed with a torque lower than the main tongs, so that the tubing at the top can be screwed together or unscrewed with the tubing fixed by the backup tongs at the bottom. This three-tong structure iron roughnecks are large in size and high in production cost, which increases the manpower and economic costs of wellhead operations.

[0004] After the iron roughneck is installed at the wellhead of the oil well, the first step to start drilling or well repair operations is to move the tongs to the position where the tubing is to be clamped. The key is to make the tongs move to the center of the tubing drill pipe before clamping the tubing. However, in actual on-site work, the iron roughneck has the problem of difficulty in alignment. When moving from the starting position to the working position, it is difficult to align the center of the tongs with the center of the tubing. The clamping action of the tongs will move the clamped end of the tubing drill pipe, causing the upper and lower tubing, which were originally vertical and had overlapping axes, to deviate from the axis, so that the axes of the upper and lower tubings cross and cannot be on the same vertical line, resulting in poor quality of make-up and make-out, and damage to the tubing threads, which reduces the life of the tubing and increases the maintenance cost of the oil well.

[0005] When the iron roughneck removes the oil pipe thread, the oil pipe at the top will move up and down in the vertical direction during the process of screwing or unscrewing the thread, and the oil pipe at the bottom will be clamped and fixed by the backup tong. In order to offset the stroke of the upper thread, the existing iron roughneck solution is to make a damping connection between the rotary tong and the backup tong. However, the structure that plays the role of damping connection not only needs to bear the force of the oil pipe floating up and down, but also needs to support the rotary tong floating with the oil pipe at the top, which is a waste of structure and material costs. Summary of the invention

[0006] In view of the several problems existing in the current iron roughneck mentioned in the background art, the present invention proposes a two-jaw iron roughneck with mechanical centering. By combining the functions of the rotary jaw and the master jaw of the original iron roughneck through the two-stage torque output of the two-stage speed-changing gear set, a structure with upper and lower jaws is realized. A hydraulic cylinder is used to provide a sufficiently large clamping force for the upper jaw clamping block and the lower jaw clamping block. At the same time, a pressure-holding cylinder is adopted to ensure sufficient and stable oil pressure of the hydraulic cylinder, so that the hydraulic cylinder does not need to be connected to an external oil pipeline, thereby eliminating the problem of oil pipeline entanglement when the hydraulic cylinder rotates at high speed together with the upper jaw clamping block. In terms of the problem of tubing centering, the present invention adopts a relatively reliable mechanical centering structure. The steering gear drives the first lever and the second lever to touch the tubing drill pipe. After the signal receiver receives the torque change signal of the steering gear, it controls the telescopic robotic arm to adjust the angle of the iron roughneck. After repeating this process several times, the clamping center of the iron roughneck can be aligned with the axis of the tubing drill pipe, thus realizing stable and reliable mechanical alignment. A floating jaw plate is proposed to solve the problem that the tubing drill pipe floats in the vertical direction during the rotation and mating process. The floating jaw plate can always clamp the drill pipe and float up and down with the drill pipe without any change in the upper jaw clamping block, offsetting the floating displacement generated during the make-up and break-out of the drill pipe.

[0007] The technical solution adopted by the present invention is as follows:

[0008] The present invention includes a telescopic robotic arm, a clamping device, and a mechanical centering mechanism; the clamping device is fixedly installed at the free end of the telescopic robotic arm through its own housing, so that the robotic arm drives the clamping device to move; the mechanical centering mechanism is fixedly installed above the clamping device, and the mechanical centering mechanism is used to guide the movement of the telescopic robotic arm;

[0009] The clamping device includes a two-stage speed-changing gear set, a hydraulic clamping system, a housing, and a cycloid motor; the two-stage speed-changing gear set and the hydraulic clamping system are installed in the housing in cooperation, the body of the cycloid motor is fixedly installed on the top surface of the housing, and the output shaft of the cycloid motor passes through the housing and is synchronously connected to the two-stage speed-changing gear set; a notch is processed at one end of the housing, and the operation object is vertically arranged in the notch of the housing. The centering area of the mechanical centering mechanism is aligned with the notch of the housing, and both the mechanical centering mechanism and the clamping device are in contact connection with the operation object through the notch of the housing.

[0010] The operation object includes an upper tubing drill pipe and a lower tubing drill pipe, and the upper tubing drill pipe and the lower tubing drill pipe are coaxially connected in sequence from top to bottom; the upper jaw clamping block and the lower jaw clamping block of the hydraulic clamping system jointly provide a clamping force for the iron roughneck, so that the upper tubing drill pipe is clamped by the upper jaw clamping block and rotates and floats up and down together with the two-stage speed-changing gear set, and the lower tubing drill pipe is completely fixed by the lower jaw clamping block.

[0011] The two-stage speed-changing gear set includes a notched large gear, a first idler gear, a second idler gear, a double-output gear, a double low-speed gear, a high-speed gear, a low-speed gear, a tooth ring, a speed-regulating ring, a speed-regulating oil cylinder and a fork; the notched large gear, the first idler gear, the second idler gear, the double-output gear, the double low-speed gear, the high-speed gear and the low-speed gear are respectively fixedly installed in the housing by being sleeved on respective struts in the housing; the cylinder block of the speed-regulating oil cylinder is arranged on the top surface of the housing, and the piston rod of the speed-regulating oil cylinder is fixedly connected with the speed-regulating ring through the fork, so that the piston rod of the speed-regulating oil cylinder drives the speed-regulating ring to move vertically in the housing through the fork, and the speed-regulating ring is respectively meshed with the low-speed gear and the high-speed gear during the vertical movement, the tooth ring is fixedly installed on the output shaft of the cycloid motor, and the output shaft of the cycloid motor is always meshed with the speed-regulating ring through the tooth ring; the high-speed gear and the low-speed gear rotate independently, the high-speed gear is meshed with the double-output gear, the low-speed gear is meshed with the double low-speed gear, the double low-speed gear is arranged directly above the double-output gear, and the double low-speed gear rotates coaxially with the double-output gear, the double-output gear is respectively meshed with the notched large gear through the first idler gear and the second idler gear, the notched large gear is a gear processed with a notch, and the notch of the notched large gear is aligned with the notch of the housing, the first idler gear and the second idler gear are symmetrically installed on both sides of the notch of the housing, and the minimum distance between the meshing point between the first idler gear and the notched large gear and the meshing point between the second idler gear and the notched large gear is always greater than the notch spacing of the notched large gear.

[0012] The hydraulic clamping system includes an oil supply oil cylinder, a first upper clamp clamping oil cylinder, a second upper clamp clamping oil cylinder, a first lower clamp clamping oil cylinder and a second lower clamp clamping oil cylinder;

[0013] The oil supply oil cylinder, the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder are all fixedly installed on the support plate above the notched large gear in the housing, and the oil supply oil cylinder, the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder all rotate synchronously with the notched large gear. A manual reversing valve is arranged in the oil pipeline of the oil supply oil cylinder, and the manual reversing valve controls the on-off of the oil path of the oil supply oil cylinder. The oil supply oil cylinder is communicated with the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder respectively through the switch of the manual reversing valve. The first lower clamp clamping oil cylinder and the second lower clamp clamping oil cylinder are both fixedly arranged below the notched large gear in the housing, and the first lower clamp clamping oil cylinder and the second lower clamp clamping oil cylinder are both supplied with oil and controlled by an external oil pipeline.

[0014] The manual reversing valve is a two-position two-way valve. One state of the manual reversing valve is to control the oil supply oil cylinder to be unidirectionally conducted with the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder at the same time, and the other state of the manual reversing valve is to control the oil supply oil cylinder to be bidirectionally conducted with the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder at the same time.

[0015] The hydraulic clamping system further includes an upper clamp clamping tooth block, which is mainly composed of an upper clamp tooth plate fixing block, a tooth plate clamping block, and an upper clamp push rod; the upper clamp tooth plate fixing block is integrally in an arc structure, and rectangular grooves are provided on the inner surfaces of both sides of the upper clamp tooth plate fixing block. Two tooth plate clamping blocks are respectively embedded in the two rectangular grooves. An upper clamp push rod is installed on the outer surface of the upper clamp tooth plate fixing block between the two rectangular grooves. The two upper clamp clamping tooth blocks are respectively fixedly connected to the piston rods of the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder through their own upper clamp push rods; so that the first upper clamp clamping oil cylinder and the second upper clamp clamping oil cylinder respectively control the two upper clamp clamping tooth blocks to clamp the operation object through the movement of their own pistons.

[0016] The tooth plate clamping block is mainly composed of a floating tooth plate, two spring guide rods, springs, a guide rod cover plate, and fastening screws; the two spring guide rods are arranged vertically in parallel and at intervals. The tops of the two spring guide rods are fixedly connected through the guide rod cover plate, and the two spring guide rods are fixedly installed in the groove of the upper clamp tooth plate fixing block through the guide rod cover plate. The floating tooth plate is sleeved on the two spring guide rods at the same time, and springs are sleeved between the floating tooth plate and the two ends of the spring guide rods on the spring guide rods. The upper clamp clamping tooth block is in contact connection with the upper oil pipe drill rod in the operation object through its own floating tooth plate, and the guide rod cover plate and the upper clamp tooth plate fixing block are bolted through the fastening screws.

[0017] The hydraulic clamping system further includes a lower clamp clamping tooth block, which is mainly composed of a lower clamp tooth plate fixing block, a fixed tooth plate, a fixing screw, and a lower clamp push rod; the lower clamp tooth plate fixing block is integrally in an arc structure, and rectangular grooves are provided on the inner surfaces of both sides of the lower clamp tooth plate fixing block. The two fixed tooth plates are respectively just embedded in the two rectangular grooves, and the fixed tooth plates are fixedly connected to the lower clamp tooth plate fixing block through the fixing screws. A lower clamp push rod is installed on the outer surface of the lower clamp tooth plate fixing block between the two rectangular grooves. The two lower clamp clamping tooth blocks are respectively fixedly connected to the piston rods of the first lower clamp clamping oil cylinder and the first lower clamp clamping oil cylinder through their own lower clamp push rods; so that the first lower clamp clamping oil cylinder and the first lower clamp clamping oil cylinder respectively control the two lower clamp clamping tooth blocks to clamp the operation object through the movement of their own pistons, and the lower clamp clamping tooth block is in contact connection with the lower oil pipe drill rod in the operation object through its own fixed tooth plate.

[0018] The mechanical centering mechanism includes a first servo motor, a second servo motor, a support, a first shift lever, and a second shift lever; the support is fixedly installed on the top surface of the housing, the first servo motor and the second servo motor are fixedly installed side by side and at intervals on the top surface of the support, a strip-shaped groove is formed on the side of the support, through holes are respectively formed on the top surface of the support directly below the first servo motor and the second servo motor, one ends of the first shift lever and the second shift lever are both embedded in the grooves formed on the support, so that the output shafts of the first servo motor and the second servo motor pass through the through holes on the top surface of the support and are respectively fixedly connected to the first shift lever and the second shift lever; so that the first servo motor and the second servo motor respectively drive the first shift lever and the second shift lever to move towards the direction close to the operation object.

[0019] Both the first servo motor and the second servo motor in the mechanical centering mechanism are electrically connected to the signal receiver in the telescopic robotic arm.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The present invention patent uses a two-stage variable-speed gear set with adjustable speed to output high and low torques, thereby replacing the master tongs and rotary tongs of the iron roughneck. The combined method simplifies the three-tong structure into an upper and a lower tong structure, which is simpler in structure, lower in economic cost, and higher in working efficiency.

[0022] 2. The present invention also proposes a hydraulic system that does not require external assurance of the internal pressure of the hydraulic cylinder. A pressure-holding cylinder is used to ensure that the hydraulic oil pressure of the hydraulic cylinder for clamping is sufficient and stable, so that the hydraulic cylinder does not need to be connected to an external oil pipeline, solving the problem of oil pipeline entanglement when the hydraulic cylinder rotates at high speed together with the upper tong.

[0023] 3. The present invention can achieve stable and reliable centering of the tubing and drill pipe, solve the problem of drill pipe damage caused by inaccurate centering of the iron roughneck, and can adapt to all sizes of tubing and drill pipe. Only the upper and lower tongs can be used to realize the make-up and break-out of the tubing and drill pipe. It has a compact structure, reliable functions, and strong practicability, and has extremely high practical value.

[0024] 4. The clamping jaw block structure adopted by the present invention is suitable for all diameters of tubing and drill pipe, eliminating the need for workers to replace the jaw blocks when facing different diameters, saving manpower. And the clamping jaw blocks can offset the make-up and break-out stroke of the drill pipe, so that the upper and lower tongs do not need to move, ensuring the stability of the iron roughneck during operation.

[0025] 5. As a new type of iron roughneck workover equipment, the present invention can greatly reduce the manufacturing cost of the existing iron roughneck. It has a simple structure, small volume, is easy to carry, and adds a mechanical alignment function on the basis of complete functions, combining economic benefits and practical effects. Description of the Drawings

[0026] Figure 1Schematic installation diagram of the two-jaw iron roughneck capable of mechanically centering tubing drill pipes according to the present invention;

[0027] Figure 2 Schematic diagram of the operation object of the two-jaw iron roughneck capable of mechanically centering tubing drill pipes according to the present invention;

[0028] Figure 3 Schematic diagram of the telescopic robotic arm structure according to the present invention;

[0029] Figure 4 Schematic diagram of the two-stage speed-changing gear set structure according to the present invention;

[0030] Figure 5 Schematic diagram of the hydraulic clamping system structure according to the present invention;

[0031] Figure 6 Schematic diagram of the mechanical centering mechanism structure according to the present invention;

[0032] Figure 7 Schematic diagram of the upper jaw clamping jaw block structure according to the present invention;

[0033] Figure 8 Schematic diagram of the lower jaw clamping jaw block structure according to the present invention.

[0034] As shown in the figure: 1. Telescopic robotic arm; 2. Two-stage speed-changing gear set; 3. Hydraulic clamping system; 4. Mechanical centering mechanism; 5. Upper jaw clamping jaw block; 6. Lower jaw clamping jaw block; 7. Housing; 8. Cycloidal motor; 9. Upper tubing drill pipe; 10. Lower tubing drill pipe; 1-1. Bottom plate; 1-2. Slewing bearing; 1-3. Support base; 1-4. Boom hydraulic cylinder; 1-5. Boom hydraulic rod; 1-6. Arm hydraulic cylinder; 1-7. Arm hydraulic rod; 1-8. Boom; 1-9. Connecting bracket; 1-10. Arm; 2-1. Notched large gear; 2-2. First idler gear; 2-3. Second idler gear; 2-4. Double-output gear; 2-5. Double low-speed gear; 2-6. High-speed gear; 2-7. Low-speed gear; 2-8. Tooth ring; 2-9. Speed-regulating ring; 2-20. Speed-regulating oil cylinder; 2-11. Fork; 3-1. Pressure-holding oil cylinder; 3-2. Oil supply oil cylinder; 3-3. Direction-changing valve oil cylinder; 3-4. Manual direction-changing valve; 3-5. First upper jaw clamping oil cylinder; 3-6. Second upper jaw clamping oil cylinder; 3-7. First lower jaw clamping oil cylinder; 3-8. Second lower jaw clamping oil cylinder; 4-1. First servo motor; 4-2. Second servo motor; 4-3. Support; 4-4. First shift lever; 4-5. Second shift lever; 5-1. Tooth plate fixing block; 5-2. Floating tooth plate; 5-3. Spring guide rod; 5-4. Upper spring; 5-5. Lower spring; 5-6. Guide rod cover plate; 5-7. Fastening screw; 5-8. Floating screw; 5-9. Push rod; 6-1. Tooth plate fixing block; 6-2. Fixed tooth plate; 6-3. Fixed screw; 6-4. Push rod. Detailed implementation mode

[0035] The present invention will be further described below with reference to the accompanying drawings.

[0036] As Figure 1 shown, the present invention includes a telescopic robotic arm 1, a clamping device, and a mechanical centering mechanism 4; the clamping device is fixedly installed at the free end of the telescopic robotic arm 1 through its own housing 7, so that the robotic arm 1 drives the clamping device to move; the mechanical centering mechanism 4 is fixedly installed above the clamping device, and the mechanical centering mechanism 4 is used to guide the movement of the telescopic robotic arm 1.

[0037] Among them, the clamping device includes a two-stage speed-changing gear set 2, a hydraulic clamping system 3, a housing 7, and a cycloid motor 8; the two-stage speed-changing gear set 2 and the hydraulic clamping system 3 for clamping the operating object are cooperatively installed in the housing 7, the body of the cycloid motor 8 is fixedly installed on the top surface of the housing 7, and the output shaft of the cycloid motor 8 passes through the housing 7 and is synchronously connected to the two-stage speed-changing gear set 2, and the cycloid motor 8 is used to drive the two-stage speed-changing gear set 2 of the clamping device; a notch is processed at one end of the housing 7, the operating object is vertically arranged in the notch of the housing 7, the centering area of the mechanical centering mechanism 4 is aligned with the notch of the housing 7, and both the mechanical centering mechanism 4 and the clamping device are in contact connection with the operating object through the notch of the housing 7.

[0038] As Figure 2 shown, the operating object includes an upper tubing drill pipe 9 and a lower tubing drill pipe 10, and the upper tubing drill pipe 9 and the lower tubing drill pipe 10 are coaxially connected in sequence from top to bottom; the upper clamping jaw block 5 and the lower clamping jaw block 6 of the hydraulic clamping system 3 jointly provide a clamping force for the iron roughneck, so that the upper tubing drill pipe 9 rotates and floats up and down together with the two-stage speed-changing gear set 2 after being clamped by the upper clamping jaw block 5, and the lower tubing drill pipe 10 is completely fixed by the lower clamping jaw block 6.

[0039] As Figure 3 shown, the telescopic robotic arm 1 includes a bottom plate 1-1, a slewing bearing 1-2, a support base 1-3, a boom hydraulic cylinder 1-4, a boom hydraulic rod 1-5, a forearm hydraulic cylinder 1-6, a forearm hydraulic rod 1-7, a boom 1-8, a connecting bracket 1-9, and a forearm 1-10; among them, the bottom plate 1-1 is fixed on the ground, the support base 1-3 is fixedly connected to the connecting bottom plate 1-1 through the slewing support 1-2, the boom 1-8 and the forearm 1-10 are respectively hinged at both ends of the connecting bracket 1-9, the connecting bracket 1-9 is movably connected to the support base 1-3 through the forearm hydraulic cylinder 1-6 and the forearm hydraulic rod 1-7, the boom 1-8 is movably connected to the slewing bearing 1-2 through the boom hydraulic cylinder 1-4 and the boom hydraulic rod 1-5, and one end of the forearm 1-10 away from the connecting bracket 1-9 is the free end fixedly connected to the housing 7.

[0040] As Figure 4As shown in the figure, the two-stage speed-changing gear set 2 includes a large notched gear 2-1, a first idle gear 2-2, a second idle gear 2-3, a double-output gear 2-4, a double low-speed gear 2-5, a high-speed gear 2-6, a low-speed gear 2-7, a gear ring 2-8, a speed-regulating ring 2-9, a speed-regulating oil cylinder 2-10 and a fork 2-11; the large notched gear 2-1, the first idle gear 2-2, the second idle gear 2-3, the double-output gear 2-4, the double low-speed gear 2-5, the high-speed gear 2-6 and the low-speed gear 2-7 are respectively fixedly installed in the housing 7 by being sleeved on respective struts within the housing 7; the cylinder body of the speed-regulating oil cylinder 2-10 is arranged on the top surface of the housing 7, and the piston rod of the speed-regulating oil cylinder 2-10 is fixedly connected to the speed-regulating ring 2-9 through the fork 2-11, such that the piston rod of the speed-regulating oil cylinder 2-10 drives the speed-regulating ring 2-9 to move vertically within the housing 7 through the fork 2-11, and during the vertical movement of the speed-regulating ring 2-9, it meshes and connects with the low-speed gear 2-7 and the high-speed gear 2-6 respectively; the gear ring 2-8 is fixedly installed on the output shaft of the cycloid motor 8, and the output shaft of the cycloid motor 8 is always meshed and connected with the speed-regulating ring 2-9 through the gear ring 2-8 to provide power for the low-speed gear 2-7 and the high-speed gear 2-6; the high-speed gear 2-6 and the low-speed gear 2-7 rotate independently, and the high-speed gear 2-6 is meshed and connected with the double-output gear 2-4, and the low-speed gear 2-7 is meshed and connected with the double low-speed gear 2-5; the double low-speed gear 2-5 is arranged directly above the double-output gear 2-4, and the double low-speed gear 2-5 rotates coaxially with the double-output gear 2-4; the double-output gear 2-4 is respectively meshed and connected with the large notched gear 2-1 through the first idle gear 2-2 and the second idle gear 2-3; the large notched gear 2-1 is a gear processed with a notch, and the notch of the large notched gear 2-1 is aligned with the notch of the housing 7, such that the operating object vertically passes through the notch of the large notched gear 2-1. The first idle gear 2-2 and the second idle gear 2-3 are symmetrically installed on both sides of the notch of the housing 7, and the minimum distance between the meshing point between the first idle gear 2-2 and the large notched gear 2-1 and the meshing point between the second idle gear 2-3 and the large notched gear 2-1 is always greater than the notch spacing of the large notched gear 2-1.

[0041] As Figure 5 shown in the figure, the hydraulic clamping system 3 includes an oil supply oil cylinder 3-2, a first upper clamp clamping oil cylinder 3-5, a second upper clamp clamping oil cylinder 3-6, a first lower clamp clamping oil cylinder 3-7 and a second lower clamp clamping oil cylinder 3-8; in addition, the pressure-holding oil cylinder 3-1 and the reversing valve oil cylinder 3-3 of the hydraulic clamping system 3 are both fixed on the housing 7, and both the pressure-holding oil cylinder 3-1 and the reversing valve oil cylinder 3-3 are connected to the external oil circuit and do not participate in the internal actions of the housing 7.

[0042] Among them, the oil supply cylinder 3-2, the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 are all fixedly installed on the support plate above the notched large gear 2-1 in the housing 7, and the oil supply cylinder 3-2, the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 all rotate synchronously with the notched large gear 2-1. A manual reversing valve 3-4 is arranged in the oil pipeline of the oil supply cylinder 3-2, and the manual reversing valve 3-4 controls the on-off of the oil circuit of the oil supply cylinder 3-2. The oil supply cylinder 3-2 is communicated with the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 respectively through the switch of the manual reversing valve 3-4, and is not communicated with the external oil circuit; the reversing valve cylinder 3-3 controls the handle switch of the manual reversing valve 3-4, and further controls the communication state between the oil supply cylinder 3-2 and the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 respectively. The first lower clamp clamping cylinder 3-7 and the second lower clamp clamping cylinder 3-8 are both fixedly arranged below the notched large gear 2-1 in the housing 7, and the first lower clamp clamping cylinder 3-7 and the second lower clamp clamping cylinder 3-8 are both supplied with oil and controlled by an external oil pipeline.

[0043] The manual reversing valve 3-4 is a two-position two-way valve. One state of the manual reversing valve 3-4 is to control the oil supply cylinder 3-2 to conduct unidirectionally with the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 at the same time, and the other state of the manual reversing valve 3-4 is to control the oil supply cylinder 3-2 to conduct bidirectionally with the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 at the same time.

[0044] As Figure 7 shown, the hydraulic clamping system 3 further includes an upper clamp clamping tooth block 5. The upper clamp clamping tooth block 5 is mainly composed of an upper clamp tooth plate fixing block 5-1, a tooth plate clamping block and an upper clamp push rod 5-9; the upper clamp tooth plate fixing block 5-1 is of an overall arc structure, and rectangular grooves are opened on the inner surfaces of both sides of the upper clamp tooth plate fixing block 5-1. Two tooth plate clamping blocks are respectively embedded in the two rectangular grooves. The inner surface of the upper clamp clamping tooth block 5 is provided with the upper clamp tooth plate fixing block 5-1 between the two rectangular grooves, and the outer surface of the upper clamp tooth plate fixing block 5-1 is provided with the upper clamp push rod 5-9 between the two rectangular grooves. The two upper clamp clamping tooth blocks 5 are fixedly connected to the piston rods of the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 respectively through their own upper clamp push rods 5-9; so that the first upper clamp clamping cylinder 3-5 and the second upper clamp clamping cylinder 3-6 respectively control the two upper clamp clamping tooth blocks 5 to clamp the operation object through their own piston movements.

[0045] The jaw plate clamping block mainly consists of a floating jaw plate 5-2, two spring guide rods 5-3, springs, a guide rod cover plate 5-6, and fastening screws 5-7. The two spring guide rods 5-3 are vertically arranged in parallel and at intervals. The tops of the two spring guide rods 5-3 are fixedly connected through the guide rod cover plate 5-6, and the two spring guide rods 5-3 are fixedly installed in the groove of the upper jaw plate fixing block 5-1 through the guide rod cover plate 5-6. The floating jaw plate 5-2 is sleeved on the two spring guide rods 5-3 at the same time, and springs are sleeved between the two ends of the floating jaw plate 5-2 and the spring guide rods 5-3 on the spring guide rods 5-3 for cooperating with the floating jaw plate 5-2 to float up and down following the operating object it clamps. Among them, the upper spring 5-4 is sleeved on the top of the spring guide rod 5-3, and the lower spring 5-5 is sleeved on the bottom of the spring guide rod 5-3. Among them, the spring guide rod 5-4 is used to ensure that the spring only generates radial displacement. And the upper jaw clamping block 5 is in contact connection with the upper tubing drill pipe 9 in the operating object through its own floating jaw plate 5-2, and the guide rod cover plate 5-6 and the upper jaw plate fixing block 5-1 are bolted through the fastening screws 5-7. The bottom surface of the floating jaw plate 5-2 is fixed on the upper jaw plate fixing block 5-1 through the floating screw 5-8.

[0046] As Figure 8 shown, the hydraulic clamping system 3 further includes a lower jaw clamping block 6. The lower jaw clamping block 6 mainly consists of a lower jaw plate fixing block 6-1, a fixed jaw plate 6-2, fixed screws 6-3, and a lower jaw push rod 6-4. The lower jaw plate fixing block 6-1 is of an overall arc structure. Rectangular grooves are provided on the inner surfaces on both sides of the lower jaw plate fixing block 6-1. The two fixed jaw plates 6-2 are respectively just embedded in the two rectangular grooves, and the fixed jaw plates 6-2 are fixedly connected with the lower jaw plate fixing block 6-1 through the fixed screws 6-3. The lower jaw push rod 6-4 is installed on the outer surface of the lower jaw plate fixing block 6-1 between the two rectangular grooves. The two lower jaw clamping blocks 6 are respectively fixedly connected with the piston rods of the first lower jaw clamping cylinder 3-7 and the first lower jaw clamping cylinder 3-8 through their own lower jaw push rods 6-4, so that the first lower jaw clamping cylinder 3-7 and the first lower jaw clamping cylinder 3-8 respectively control the two lower jaw clamping blocks 6 to clamp the operating object through the movement of their own pistons, and the lower jaw clamping block 6 is in contact connection with the lower tubing drill pipe 10 in the operating object through its own fixed jaw plate 6-2.

[0047] As Figure 6As shown in the figure, the mechanical centering mechanism 4 includes a first servo motor 4-1, a second servo motor 4-2, a support 4-3, a first shift lever 4-4 and a second shift lever 4-5; the support 4-3 is fixedly installed on the top surface of the housing 7 to provide support for the first servo motor 4-1, the second servo motor 4-2, the first shift lever 4-4 and the second shift lever 4-5. The first servo motor 4-1 and the second servo motor 4-2 are fixedly installed side by side and at intervals on the top surface of the support 4-3. A strip-shaped groove is formed on the side of the support 4-3, and through holes are respectively formed on the top surface of the support 4-3 directly below the first servo motor 4-1 and the second servo motor 4-2. One end of the first shift lever 4-4 and one end of the second shift lever 4-5 are both embedded in the groove formed in the support 4-3, so that the output shafts of the first servo motor 4-1 and the second servo motor 4-2 pass through the through holes on the top surface of the support 4-3 and are fixedly connected to the first shift lever 4-4 and the second shift lever 4-5 respectively; the first servo motor 4-1 and the second servo motor 4-2 drive the first shift lever 4-4 and the second shift lever 4-5 to move synchronously in the direction close to the operation object.

[0048] Among them, both the first servo motor 4-1 and the second servo motor 4-2 in the mechanical centering mechanism 4 are electrically connected to the signal receiver in the telescopic robotic arm 1, so that the output torques of the first servo motor 4-1 and the second servo motor 4-2 are transmitted to the signal receiver in the telescopic robotic arm 1 in real time, and then the movement of the telescopic robotic arm 1 is adjusted.

[0049] The process of the iron roughneck screwing on and unscrewing the operation object at the oil wellhead is as follows:

[0050] The first step: Centering the upper tubing drill pipe 9 and the lower tubing drill pipe 10 in the operation object: First, after installing the bottom plate 1-1 of the telescopic robotic arm 1 at the designated position, the clamping device is roughly adjusted to a position close to the upper tubing drill pipe 9 and the lower tubing drill pipe 10 through the telescopic robotic arm 1; then the telescopic robotic arm 1 pushes the jaw part where the housing 7 is located in the direction close to the upper tubing drill pipe 9, so that the housing 7 is stuck outside the upper tubing drill pipe 9 and the lower tubing drill pipe 10 through its own notch. Since the position center of the operation object cannot be accurately identified, at this time, the central axes of the upper tubing drill pipe 9 and the lower tubing drill pipe 10 do not coincide with the notch center of the housing 7.

[0051] Afterwards, the first steering gear 4-1 and the second steering gear 4-2 in the mechanical centering mechanism 4 drive the second shift lever 4-5 and the first shift lever 4-4 respectively to move synchronously towards the direction close to the upper tubing drill pipe 9. Moreover, the second shift lever 4-5 and the first shift lever 4-4 are always symmetrically distributed on both sides of the notch of the housing 7 with the upper tubing drill pipe 9 as the center. Since the central axis of the operation object has not yet coincided with the center of the notch of the housing 7, when the second shift lever 4-5 and the first shift lever 4-4 move synchronously towards the center of the notch of the housing 7, the shift lever on one side of the notch will first touch the upper tubing drill pipe 9. When the inner side of the second shift lever 4-5 or the first shift lever 4-4 touches the upper tubing drill pipe 9, the output torque of the driving steering gear corresponding to the shift lever becomes larger. At this time, the first steering gear 4-1 and the second steering gear 4-2 transmit their output torque signals to the signal receiver of the telescopic robotic arm 1, so that the telescopic robotic arm 1 drives the telescopic robotic arm 1 to rotate at a low speed and a small angle through the slewing bearing 1-2 according to the torque signal, thereby reducing the distance between the central axis of the upper tubing drill pipe 9 and the center of the notch of the housing 7. After adjustment, the first steering gear 4-1 and the second steering gear 4-2 are again made to drive the second shift lever 4-5 and the first shift lever 4-4 respectively to perform the same action, and then the rotation of the slewing bearing 1-2 is controlled again according to the torque signal. After repeating the operations of driving the shift lever - extracting the signal - slewing bearing rotation several times according to the actual situation, when the second shift lever 4-5 and the first shift lever 4-4 touch the upper tubing drill pipe 9 simultaneously, that is, when the output torques of the first steering gear 4-1 and the second steering gear 4-2 are the same, the slewing bearing 1-2 no longer controls the rotation of the telescopic robotic arm 1. At this time, the central axis of the upper tubing drill pipe 9 coincides with the center position of the notch of the housing 7. Therefore, problems such as poor make-up and break-out quality and thread damage caused by the offset of the central axes of the upper tubing drill pipe 9 and the lower tubing drill pipe 10 can be reduced.

[0052] Step 2: Make up or break out the upper tubing drill pipe 9 and the lower tubing drill pipe 10 in the operation object: Both the make-up and break-out of the tubing drill pipe include two processes of buckling and rotation. Buckling requires the upper tubing drill pipe 9 to rotate at a low speed and with a large torque, and rotation requires the upper tubing drill pipe 9 to rotate at a high speed and with a small torque. When making up, rotate first and then buckle; when breaking out, buckle first and then rotate.

[0053] Before making up or breaking out, the upper tubing drill pipe 9 and the lower tubing drill pipe 10 need to be clamped and fixed respectively. Specifically: The pressure maintaining oil cylinder 3-1 is used to push the oil supply oil cylinder 3-2, so that the pressure oil in the oil supply oil cylinder 3-2 simultaneously flows into the first upper clamp clamping oil cylinder 3-5 and the second upper clamp clamping oil cylinder 3-6 through the manual reversing valve 3-4, thereby pushing the two upper clamp clamping blocks 5 out simultaneously to clamp the upper tubing drill pipe 9; in addition, the first lower clamp clamping oil cylinder 3-7 and the second lower clamp clamping oil cylinder 3-8 controlled by external oil supply respectively push the two lower clamp clamping blocks 6 to clamp the lower tubing drill pipe 10.

[0054] When performing the thread loosening between the upper tubing drill pipe 9 and the lower tubing drill pipe 10, the speed-regulating oil cylinder 2-10 drives the speed-regulating ring 2-9 to move vertically upward through the fork 2-11, so that the speed-regulating ring 2-9 is simultaneously engaged with the gear ring 2-8 and the low-speed gear 2-7, causing the speed-regulating ring 2-9 and the low-speed gear 2-7 to rotate synchronously with the gear ring 2-8. The low-speed gear 2-7 drives the double low-speed gear 2-5 to rotate through gear engagement, and then drives the notched large gear 2-1 through the double-output gear 2-4, the first idler gear 2-2 and the second idler gear 2-3, so that the two upper clamp clamping blocks 5 fixed above the notched large gear 2-1 clamp the upper tubing drill pipe 9 and rotate at a low speed together. At this time, the low-speed rotation can loosen or clamp the threads of the upper tubing drill pipe 9 and the lower tubing drill pipe 10.

[0055] When rotating between the upper tubing drill pipe 9 and the lower tubing drill pipe 10, the speed-regulating oil cylinder 2-10 is used to drive the speed-regulating ring 2-9 to move vertically downward through the fork 2-11, so that the speed-regulating ring 2-9 is simultaneously engaged with the gear ring 2-8 and the high-speed gear 2-6, causing the high-speed gear 2-6 to rotate synchronously with the gear ring 2-8. The high-speed gear 2-6 drives the notched large gear 2-1 step by step through the double-output gear 2-4, the first idler gear 2-2 and the second idler gear 2-3, so that the two upper clamp clamping blocks 5 fixed above the notched large gear 2-1 clamp the upper tubing drill pipe 9 and rotate at a high speed together.

[0056] At the same time, in order to ensure that the upper tubing drill pipe 9 can always be clamped during the thread loosening and rotation processes, the action frequency of the pressure-holding oil cylinder 3-1 is kept consistent with the rotation frequency of the notched large gear 2-1. Each time the oil supply oil cylinder 3-2 passes directly below the pressure-holding oil cylinder 3-1, the push rod of the pressure-holding oil cylinder 3-1 is pressed down to provide pressure for the oil in the oil chamber of the oil supply oil cylinder 3-2 and push out the oil, so that the oil pressure in the first upper clamp clamping oil cylinder 3-5 and the second upper clamp clamping oil cylinder 3-6 is always stable, thus ensuring that the clamping force of the upper clamp clamping block 5 acting on the upper tubing drill pipe 9 is sufficient.

[0057] During the rotation with the notched large gear 2-1, the upper tubing drill pipe 9 floats up and down due to threading or unthreading. Under the combined action of the upper spring 5-4 and the lower spring 5-5, the floating jaw plate 5-2 of the jaw plate clamping block clamps the upper tubing drill pipe 9 and floats up and down with the upper tubing drill pipe 9 at the same time; the elastic deformations of the upper spring 5-4 and the lower spring 5-5 offset the floating displacement of the upper tubing drill pipe 9, avoiding the movement of other parts of the iron roughneck. When the floating jaw plate 5-2 is not subjected to the vertical force from the upper tubing drill pipe 9, the upper spring 5-4 and the lower spring 5-5 with the same elastic coefficient can make the floating jaw plate 5-2 automatically return to its original position.

[0058] After completing the make-up and breakout operations, the handle of the manual reversing valve 3-4 is pushed by the reversing valve oil cylinder 3-3 to switch the state of the manual reversing valve 3-4 to two-way conduction. The high-pressure hydraulic oil in the first upper clamp clamping oil cylinder 3-5 and the second upper clamp clamping oil cylinder 3-6 flows to the oil supply oil cylinder 3-2 that is not affected by the pressure-maintaining oil cylinder 3-1, and the upper clamp clamping jaw block 5 releases the upper tubing drill pipe 9; the high-pressure hydraulic oil of the first lower clamp clamping oil cylinder 3-7 and the first lower clamp clamping oil cylinder 3-8 directly returns to the external oil tank, the lower clamp clamping jaw block 6 releases the lower tubing drill pipe 10, and the telescopic robotic arm 1 drives the tong head part of the iron roughneck away from the oil well wellhead.

[0059] As can be seen from the implementation, the present invention can clamp and mechanically center tubing drill pipes of different sizes, and can achieve the make-up and breakout of tubing drill pipes through two-stage speed regulation.

Claims

1. A two-jaw iron roughneck for mechanically centering tubing drill pipes, characterized in that: it includes a telescopic robotic arm (1), a clamping device, and a mechanical centering mechanism (4); the clamping device is fixedly installed at the free end of the telescopic robotic arm (1) through its own housing (7), so that the robotic arm (1) drives the clamping device to move; the mechanical centering mechanism (4) is fixedly installed above the clamping device, and the mechanical centering mechanism (4) is used to guide the movement of the telescopic robotic arm (1); the clamping device includes a two-stage speed-changing gear set (2), a hydraulic clamping system (3), a housing (7), and a cycloidal motor (8); the two-stage speed-changing gear set (2) and the hydraulic clamping system (3) are cooperatively installed in the housing (7), the body of the cycloidal motor (8) is fixedly installed on the top surface of the housing (7), and the output shaft of the cycloidal motor (8) passes through the housing (7) and is synchronously connected to the two-stage speed-changing gear set (2); one end of the housing (7) is machined with a notch, the operating object is vertically arranged in the notch of the housing (7), the centering area of the mechanical centering mechanism (4) is aligned with the notch of the housing (7), and both the mechanical centering mechanism (4) and the clamping device are in contact connection with the operating object through the notch of the housing (7); the hydraulic clamping system (3) includes an oil supply cylinder (3-2), a first upper jaw clamping cylinder (3-5), a second upper jaw clamping cylinder (3-6), a first lower jaw clamping cylinder (3-7), and a second lower jaw clamping cylinder (3-8); the oil supply cylinder (3-2), the first upper jaw clamping cylinder (3-5), and the second upper jaw clamping cylinder (3-6) are all fixedly installed on the support plate above the large gear (2-1) in the notch of the housing (7), and the oil supply cylinder (3-2), the first upper jaw clamping cylinder (3-5), and the second upper jaw clamping cylinder (3-6) all rotate synchronously with the large gear (2-1) in the notch, a manual reversing valve (3-4) is arranged in the oil pipeline of the oil supply cylinder (3-2), and the manual reversing valve (3-4) controls the on-off of the oil circuit of the oil supply cylinder (3-2), and the oil supply cylinder (3-2) is communicated with the first upper jaw clamping cylinder (3-5) and the second upper jaw clamping cylinder (3-6) respectively through the opening and closing of the manual reversing valve (3-4). The first lower jaw clamping cylinder (3-7) and the second lower jaw clamping cylinder (3-8) are both fixedly arranged below the large gear (2-1) in the notch of the housing (7), and the first lower jaw clamping cylinder (3-7) and the second lower jaw clamping cylinder (3-8) are both supplied with oil and controlled by an external oil pipeline; The mechanical centering mechanism (4) includes a first servo motor (4-1), a second servo motor (4-2), a support (4-3), a first lever (4-4) and a second lever (4-5); the support (4-3) is fixedly installed on the top surface of the housing (7), the first servo motor (4-1) and the second servo motor (4-2) are fixedly installed side by side and at intervals on the top surface of the support (4-3), a strip-shaped groove is formed on the side of the support (4-3), through holes are respectively formed on the top surface of the support (4-3) directly below the first servo motor (4-1) and the second servo motor (4-2), one end of the first lever (4-4) and one end of the second lever (4-5) are both embedded in the groove formed in the support (4-3), so that the output shafts of the first servo motor (4-1) and the second servo motor (4-2) pass through the through holes on the top surface of the support (4-3) and are respectively fixedly connected to the first lever (4-4) and the second lever (4-5); the first servo motor (4-1) and the second servo motor (4-2) respectively drive the first lever (4-4) and the second lever (4-5) to move towards the direction close to the operating object.

2. The two-jaw iron roughneck for mechanically centering tubing drill pipes according to claim 1, characterized in that: the operating object includes an upper tubing drill pipe (9) and a lower tubing drill pipe (10), the upper tubing drill pipe (9) and the lower tubing drill pipe (10) are coaxially connected in sequence from top to bottom; the upper clamping jaw block (5) and the lower clamping jaw block (6) of the hydraulic clamping system (3) jointly provide a clamping force for the iron roughneck, so that the upper tubing drill pipe (9) rotates and floats up and down together with the two-stage speed-changing gear set (2) after being clamped by the upper clamping jaw block (5), and the lower tubing drill pipe (10) is completely fixed by the lower clamping jaw block (6).

3. The two-jaw iron roughneck for mechanically centering tubing drill pipes according to claim 1, characterized in that: The two-stage speed-changing gear set (2) includes a notched large gear (2-1), a first idler gear (2-2), a second idler gear (2-3), a double-output gear (2-4), a double low-speed gear (2-5), a high-speed gear (2-6), a low-speed gear (2-7), a tooth ring (2-8), a speed-regulating ring (2-9), a speed-regulating oil cylinder (2-10) and a fork (2-11); the notched large gear (2-1), the first idler gear (2-2), the second idler gear (2-3), the double-output gear (2-4), the double low-speed gear (2-5), the high-speed gear (2-6) and the low-speed gear (2-7) are respectively fixedly installed in the housing (7) by being sleeved on respective struts inside the housing (7); the cylinder block of the speed-regulating oil cylinder (2-10) is arranged on the top surface of the housing (7), and the piston rod of the speed-regulating oil cylinder (2-10) is fixedly connected with the speed-regulating ring (2-9) through the fork (2-11), so that the piston rod of the speed-regulating oil cylinder (2-10) drives the speed-regulating ring (2-9) to vertically move inside the housing (7) through the fork (2-11), and during the vertical movement of the speed-regulating ring (2-9), the speed-regulating ring (2-9) is respectively meshed and connected with the low-speed gear (2-7) and the high-speed gear (2-6); the tooth ring (2-8) is fixedly installed on the output shaft of the cycloid motor (8), and the output shaft of the cycloid motor (8) is always meshed and connected with the speed-regulating ring (2-9) through the tooth ring (2-8); the high-speed gear (2-6) and the low-speed gear (2-7) rotate independently, and the high-speed gear (2-6) is meshed and connected with the double-output gear (2-4), and the low-speed gear (2-7) is meshed and connected with the double low-speed gear (2-5); the double low-speed gear (2-5) is arranged directly above the double-output gear (2-4), and the double low-speed gear (2-5) rotates coaxially with the double-output gear (2-4); the double-output gear (2-4) is respectively meshed and connected with the notched large gear (2-1) through the first idler gear (2-2) and the second idler gear (2-3); the notched large gear (2-1) is a gear processed with a notch, and the notch of the notched large gear (2-1) is aligned with the notch of the housing (7); the first idler gear (2-2) and the second idler gear (2-3) are symmetrically installed on both sides of the notch of the housing (7), and the minimum distance between the meshing point between the first idler gear (2-2) and the notched large gear (2-1) and the meshing point between the second idler gear (2-3) and the notched large gear (2-1) is always greater than the notch spacing of the notched large gear (2-1).

4. A two-tong type iron roughneck for mechanically centering tubing drill pipes according to claim 1, characterized in that: The manual reversing valve (3-4) is a two-position, two-way valve. One state of the manual reversing valve (3-4) is to control the oil supply cylinder (3-2) to simultaneously communicate with the first upper clamp clamping cylinder (3-5) and the second upper clamp clamping cylinder (3-6) in a unidirectional manner. Another state of the manual reversing valve (3-4) is to control the oil supply cylinder (3-2) to simultaneously communicate with the first upper clamp clamping cylinder (3-5) and the second upper clamp clamping cylinder (3-6) in a bidirectional manner.

5. A two-tongs iron roughneck capable of mechanically centering an oil pipe drill pipe according to claim 1, Features: The hydraulic clamping system (3) also includes an upper clamp clamping tooth block (5), which is mainly composed of an upper clamp tooth plate fixing block (5-1), a tooth plate clamping block and an upper clamp push rod (5-9); the upper clamp tooth plate fixing block (5-1) is an arc structure as a whole, and rectangular grooves are opened on the inner surface of both sides of the upper clamp tooth plate fixing block (5-1), and the two tooth plate clamping blocks are respectively embedded in the two rectangular grooves; the outer surface of the upper clamp tooth plate fixing block (5-1) is provided with an upper clamp push rod (5-9) between the two rectangular grooves, and the two upper clamp clamping tooth blocks (5) are respectively fixedly connected to the piston rods of the first upper clamp clamping oil cylinder (3-5) and the second upper clamp clamping oil cylinder (3-6) through their own upper clamp push rods (5-9); so that the first upper clamp clamping oil cylinder (3-5) and the second upper clamp clamping oil cylinder (3-6) respectively control the two upper clamp clamping tooth blocks (5) to clamp the operation object through their own piston movement.

6. A two-tongs iron roughneck capable of mechanically centering an oil pipe drill pipe according to claim 5, Features: The tooth plate clamping block is mainly composed of a floating tooth plate (5-2), two spring guide rods (5-3), a spring, a guide rod cover plate (5-6), and a fastening screw (5-7); the two spring guide rods (5-3) are vertically arranged in parallel with each other and spaced apart, the top ends of the two spring guide rods (5-3) are fixedly connected by the guide rod cover plate (5-6), and the two spring guide rods (5-3) are fixedly installed in the groove of the upper jaw tooth plate fixing block (5-1) through the guide rod cover plate (5-6). The floating tooth plate (5-2) is simultaneously mounted on two spring guide rods (5-3), and springs are mounted between the two ends of the floating tooth plate (5-2) and the spring guide rod (5-3), and the upper clamping tooth block (5) is contacted and connected with the upper tubing drill rod (9) in the operation object through its own floating tooth plate (5-2), and the guide rod cover plate (5-6) is bolted to the upper clamping tooth plate fixing block (5-1) through a fastening screw (5-7).

7. A two-tongs iron roughneck capable of mechanically centering an oil pipe drill pipe according to claim 1, Features: The hydraulic clamping system (3) further includes lower clamp clamping jaw blocks (6), and each lower clamp clamping jaw block (6) mainly consists of a lower clamp jaw plate fixing block (6-1), a fixed jaw plate (6-2), a fixing screw (6-3) and a lower clamp push rod (6-4); the lower clamp jaw plate fixing block (6-1) is of an overall arc structure, rectangular grooves are formed in the inner surfaces on both sides of the lower clamp jaw plate fixing block (6-1), the two fixed jaw plates (6-2) are respectively just embedded in the two rectangular grooves, and the fixed jaw plates (6-2) are fixedly connected with the lower clamp jaw plate fixing block (6-1) through the fixing screws (6-3), a lower clamp push rod (6-4) is installed on the outer surface of the lower clamp jaw plate fixing block (6-1) between the two rectangular grooves, and the two lower clamp clamping jaw blocks (6) are respectively fixedly connected with the piston rods of a first lower clamp clamping oil cylinder (3-7) and a first lower clamp clamping oil cylinder (3-8) through their respective lower clamp push rods (6-4); so that the first lower clamp clamping oil cylinder (3-7) and the first lower clamp clamping oil cylinder (3-8) respectively control the two lower clamp clamping jaw blocks (6) to clamp an operation object through the movement of their own pistons, and the lower clamp clamping jaw blocks (6) are in contact connection with the lower oil pipe drill pipe (10) in the operation object through their own fixed jaw plates (6-2).

8. A two-jaw iron roughneck for mechanically centering an oil pipe drill pipe according to claim 1, characterized in that: both the first servo motor (4-1) and the second servo motor (4-2) in the mechanical centering mechanism (4) are electrically connected to a signal receiver in the telescopic robotic arm (1).

Images