Coupling pre-twisting machine

Abstract

The invention relates to a coupling pre-screwing machine, and relates to the field of threaded pipes and couplings. Comprising a coupling feeding mechanism, a mechanical arm, an operation tool, a pre-screwing trolley, a rotary pre-screwing mechanism and a visual identification mechanism, the coupling feeding mechanism comprises a material storage frame and a feeding groove, the operation tool is installed on the mechanical arm and provided with a material taking handle and an elastic grabbing clamp, and the pre-screwing trolley is provided with an electromagnetic chuck used for supporting a coupling; the material taking handle is driven by the mechanical arm to transfer a coupling from the feeding groove to the electromagnetic chuck, the elastic grabbing clamp grabs a handle of the pre-screwing trolley, the pre-screwing trolley is driven by the mechanical arm to axially advance and retreat relative to a pipe body, the pre-screwing trolley is provided with a floating lifting adjusting mechanism, and the pre-screwing mechanism is rotated to drive the pipe body to rotate to complete pre-screwing with the coupling. The visual recognition mechanism is used for monitoring and calculating the meshing length of the pipe body and the coupling. The coupling pre-screwing machine is high in automation degree, good in pre-screwing and buckling effect and free of damage to threads.

Description

Technical Field

[0001] The invention relates to the field of petroleum machinery and equipment, in particular to a coupling feeding and coupling automatic pre-tightening machine. Background Art

[0002] During the production of oil pipes or casing, couplings must be pre-threaded onto the pipe body and a certain thread length must be properly screwed between the coupling and the pipe body. This process, which occurs before the coupling screwing machine tightens the couplings to the required torque, is called coupling pre-tightening, and the associated equipment is called a coupling pre-tightening machine. Existing coupling pre-tightening designs include CN 118060867 A, CN203292783U, CN 213135770 U, and CN 214489495 U.

[0003] There are three common ways to pre-tighten couplings: 1. Manual pre-tightening The operator moves the coupling onto the pipe and manually rotates it until the coupling threads engage correctly with the pipe threads for a certain distance. This pre-tightening method has the following advantages: no equipment investment is required, and there is no risk of thread damage caused by forced tightening when the coupling and pipe threads are not properly engaged. The coupling and pipe are manually screwed together, preventing scratches on the coupling or pipe surfaces. However, the disadvantages are low production efficiency and inability to adapt to the pace of automated oil casing production lines. The operator also faces high labor intensity and a harsh working environment.

[0004] 2. Semi-automatic pre-tightening The coupling is manually carried and placed into the coupling caliper. The cylinder is activated and the caliper locks the coupling. The pipe body is driven to rotate on the rotating rollers. The operator pushes the trolley to gradually move the coupling closer to the pipe body. When the two threads are engaged, the coupling trolley is automatically driven forward by the screwing threads. When the screwing torque is greater than the driving torque of the rollers, the pipe body stops rotating. The operator releases the coupling caliper and drags the coupling trolley to completely withdraw the coupling from the caliper, completing the coupling pre-tightening.

[0005] The advantages of this method are simple equipment and low investment. The coupling screwing action is completed by the equipment, which reduces labor intensity and speeds up production. However, the disadvantage is that because the coupling is fixed, the pipe body is simply placed freely on the rollers. However, when the threads of the coupling and pipe body are screwed together, the misalignment between the two causes the pipe body to swing. Because the pipe body is long and heavy, this swinging action can easily damage the threads and scratch the pipe body.

[0006] 3. Automatic pre-tightening At the pre-tightening station, the pipe body is locked by the automatic center caliper. The pipe body does not rotate, and the coupling is automatically loaded by the equipment. When the coupling is lifted to the set position by the pallet, the pre-tightening carriage advances from the preparation position to the loading position and stops. The hydraulic cylinder drives the rack of the three-jaw caliper to move the coupling. After the coupling is clamped, the coupling pallet drops, and the hydraulic motor drives the main shaft to rotate, driving the caliper mechanism to clamp the coupling and rotate it together. At the same time, the pre-tightening carriage continues to move toward the pipe body, gradually approaching the coupling, gradually completing the fastening and tightening until the coupling is screwed to the pipe body to the set engagement length. After the pre-tightening carriage advances to the set position (to ensure the engagement length), the claws are released and the carriage returns to the preparation position, completing the pre-tightening cycle and preparing for the next coupling. Advantages include automated operation and high efficiency. The jaws on the pre-tightening carriage are fully floating, and a hydraulic cylinder with a pressure sensor controls the coupling's movement during the tightening process, ensuring that the threads are not damaged. The disadvantages are that the pre-tightening equipment is complex and requires a huge investment. During operation, due to its fully floating design, the floating trolley swings widely, resulting in numerous equipment failure points. During operation, adjusting the clamping pressure of the jaws is difficult. If the pressure is too low, the coupling can easily dive, resulting in poor alignment between the coupling and the pipe, poor pre-tightening results, and the risk of misthreading. If the pressure is too high, the jaws and coupling can slip due to excessive tightening torque, easily scratching the coupling surface. Summary of the Invention

[0007] The purpose of the present invention is to provide a coupling pre-tightening machine in response to the above-mentioned prior art, which is combined with a robotic arm to realize the loading of couplings onto a pre-tightening trolley, and the pre-tightening trolley floats forward and backward. It is combined with visual recognition technology to monitor the engagement length of the coupling and the pipe and determine the degree of pre-tightening completion.

[0008] The technical solution adopted by the present invention is: a coupling pre-tightening machine, characterized in that it includes a coupling feeding mechanism, a mechanical arm, an operating tool, a pre-tightening trolley, a rotating pre-tightening mechanism and a visual recognition mechanism, the coupling feeding mechanism includes a material storage frame and a feeding trough, the feeding trough has a coupling picking station, the operating tool is installed on the mechanical arm, the operating tool has a picking handle and an elastic gripper, the pre-tightening trolley has an electromagnetic suction cup for supporting the coupling, and the picking handle drives the coupling to be picked up by the mechanical arm. It is transferred from the feeding chute to the electromagnetic suction cup, and the elastic clamp grabs the handle of the pre-tightening trolley. The pre-tightening trolley is moved forward and backward relative to the axial direction of the pipe body under the drive of the mechanical arm. The pre-tightening trolley has a floating lifting and adjusting mechanism. The rotating pre-tightening mechanism includes several groups of axially arranged rotating wheels. The pipe body pre-tightened with the coupling is supported on several groups of rotating wheels. The rotating wheels are driven to rotate the pipe body to complete pre-tightening with the coupling. The visual recognition mechanism is used to monitor and calculate the engagement length of the pipe body and the coupling.

[0009] Preferably, the front end of the feeding chute of the coupling feeding mechanism starts from the material storage frame, the end height is lower than the front end and a material baffle is provided, the downslope angle of the feeding chute is 10°, and a fixed side plate is provided on one side of the two sides of the feeding chute and a movable side plate is provided on the other side. The movable side plate can adjust the distance relative to the fixed side plate to realize the adjustment of the width of the feeding chute to adapt to the loading of couplings of different lengths.

[0010] Preferably, the electromagnetic chuck has a V-shaped groove, and the coupling falls into the V-shaped groove. When the electromagnetic chuck is energized, magnetic adsorption is generated to fix the coupling, but this fixation is not rigid. The coupling can still move relative to the electromagnetic chuck under external force, avoiding the coupling being unable to follow the rotation and damaging the thread after the coupling and the pipe body are wrongly fastened.

[0011] Preferably, the working tooling includes a part sleeve, a core shaft, and a material picking handle. A flange edge is provided at the top of the part sleeve, and the flange edge is connected to the robotic arm through a connecting bolt; the material picking handle is formed on the outside of the part sleeve, and a positioning step is provided at the proximal end of the material picking handle; the core shaft is vertically arranged in the part sleeve, and the upper end of the core shaft is suspended on the part sleeve and can rotate freely relative to the part sleeve. A torsion spring is provided on the surface of the core shaft, and the core shaft always has a tendency to rotate and reset due to the restriction of the torsion spring, and the torsion spring has an axial shock-absorbing effect. The core shaft has a frustum, and one end of the torsion spring acts on the frustum. The size of the frustum coincides with the internal size of the part sleeve; the lower end of the core shaft is exposed from the part sleeve, and the elastic gripper is provided at the lower end of the core shaft.

[0012] Preferably, the surface of the material taking handle is covered with a rubber sleeve, and the coupling is hung on the rubber sleeve to protect it and avoid scratches.

[0013] Preferably, the structure of the elastic clamp is that splints are respectively provided on both sides of the lower end of the core shaft, and the first connecting rod passes horizontally through the two splints and the middle core shaft, and the two splints can move relative to each other along the first connecting rod, and at the same time, the two ends of the first connecting rod form a limit for the two splints; the second connecting rod passes horizontally through the two splints and the middle core shaft, and at the same time, the two ends of the second connecting rod are respectively covered with compression springs, and the compression springs at both ends act on the splints on the same side respectively, so that the two splints always have a tendency to clamp relatively, and the thickness of the lower end of the core shaft is less than the thickness of the handle of the pre-tightening trolley, and the two splints can reliably clamp the handle of the pre-tightening trolley.

[0014] Preferably, the pre-tightening trolley comprises a frame, a slider, a transverse track, and an electromagnetic chuck. The slider is disposed at the bottom of the frame and slidably engages with a linear track on the upper seat, allowing the frame to move axially relative to the upper seat. The transverse track is disposed on the frame, and the electromagnetic chuck slides on the transverse track, moving laterally along the transverse track. The linear track is parallel to the central axis of the coupling, and the transverse track is perpendicular to the central axis of the coupling, thereby achieving axial and lateral displacement of the coupling.

[0015] Preferably, the pre-tightening trolley also includes a base, a lifting cylinder is provided on the base, the lifting cylinder acts on the upper seat to lift and lower relative to the base, the upper seat is provided with a plurality of guide columns, and the base is correspondingly provided with a plurality of sliding sleeves, the guide columns are slidably arranged in the sliding sleeves one by one, the sliding sleeve includes a copper sleeve, a graphite copper sleeve and a copper sleeve cover, the graphite copper sleeve is arranged on the inner wall of the copper sleeve, and the copper sleeve cover is arranged at the port position of the copper sleeve and the graphite copper sleeve.

[0016] Preferably, the visual recognition mechanism is to monitor the displacement of the coupling / pre-tightening trolley in combination with a camera and calculate the engagement length of the coupling and the pipe body. The camera is preferably installed on a robotic arm. During the recognition process, it is necessary to use a ruler on the edge of the electromagnetic suction cup. The ruler is fixedly set on the edge of the electromagnetic suction cup, and the scale of the ruler is clear and can be recognized by the camera; the robotic arm operates the material picking handle to transfer the coupling to the electromagnetic suction cup (of the pre-tightening trolley at the pre-tightening starting position). After the pipe body starts to rotate, the robotic arm pushes the pre-tightening trolley from the pre-tightening starting position to the pipe body. The pre-tightening trolley continues to move until the coupling and the pipe body are buckled and continue to be tightened. During the tightening process, the pre-tightening trolley continues to move, and the coupling will also move relative to the electromagnetic chuck. Wait for the robotic arm to move to the pre-set pre-tightening completion position and pause; the camera takes a picture and uses vision to identify the position reading of the end of the coupling, that is, the non-pre-tightening end on the ruler and calculate the comparison difference of the position reading of the end of the coupling before and after pre-tightening, and calculate the engagement length accordingly. If the engagement length meets the design requirements of the pre-tightening screwing length, the pre-tightening is completed, and the robotic arm drives the pre-tightening trolley to reset, otherwise, an alarm is issued.

[0017] Preferably, the recognition method of the visual recognition mechanism and the calculation method of the meshing length are as follows: the end face of the steel wire, i.e. the pre-tightening end of the pipe body, is used as the reference point (it is assumed that the pipe body does not undergo axial displacement changes during the entire pre-tightening process). In order to ensure that the moving distance of the coupling on the electromagnetic chuck can be monitored, the end of the coupling during the entire pre-tightening process must fall within the measuring range of the scale; when the pre-tightening trolley stops at the pre-tightening starting position, the distance reading of the position of the coupling end on the scale relative to the starting end of the scale is recorded as A, and the distance between the starting end of the scale and the steel wire is recorded as B; after the pre-tightening trolley reaches the pre-tightening completion position, the moving distance of the pre-tightening trolley is recorded as C, and the distance reading of the position of the coupling end on the scale relative to the starting end of the scale is recorded as D. In order to ensure the smooth implementation of the pre-tightening process and the identification and monitoring of the implementation process, the following conditions must be met: A>S+hH, and A>0; B>H+A; B-(H+A)+h ≤C≤BS, where H is the coupling length, S is the scale length, and h is the shortest engagement length. Within this range, a suitable moving distance is set for the pre-tightening trolley. After the pre-tightening trolley has completed the set moving distance, D is used to determine whether the pre-tightening is in place. The determination method is: the actual engagement length should be greater than the minimum engagement length, that is, D+C+HB≥h.

[0018] Compared with the prior art, the advantages of the present invention are: the coupling pre-tightening machine has a high degree of automation, good pre-tightening and fastening effect, and does not damage the thread threads.

[0019] The use of a robotic arm combined with working tools for loading makes loading simple and convenient, with low failure rate and high repeatability.

[0020] The pre-tightening trolley is pushed and pulled by a mechanical arm to move the coupling trolley forward and backward. It has a simple structure, reliable movement and high repeatability of the pre-tightening operation.

[0021] When pre-tightening, the centering effect is good and it is not easy to cause wrong threading.

[0022] Even if the alignment effect is poor due to the straightness of the steel pipe, in addition to the electromagnetic suction cup on the pre-tightening trolley floating left and right to prevent thread damage, the magnetic adsorption is not rigidly fixed to avoid forced connection after the coupling and the pipe body are wrongly fastened, which may cause thread damage.

[0023] Using visual recognition technology to determine the completion of pre-tightening, it can automatically report errors and reduce the intensity of workers' inspection work. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the operation of the coupling pre-tightening machine according to an embodiment of the present invention, excluding the feeding mechanism; Figure 2 It is a structural diagram of the feeding mechanism; Figure 3 It is a structural cross-sectional view of the work tool; Figure 4 This is a schematic diagram of the material removal of the butt collar of the working tool; Figure 5 Pre-tighten the handle of the trolley for the work tooling clamp; Figure 6 This is a structural diagram of the pre-tightening trolley; Figure 7 This is a schematic diagram of the operation of the robotic arm pushing the pre-tightening trolley; Figure 8 This is a top view of the pre-tightening trolley; Figure 9 This is a schematic diagram of the camera's recognition and monitoring of the pre-tightening process; Figure 10 This is the displacement process diagram of the pre-tightening trolley; Figure 11 It is a structural diagram of the rotary pre-tightening mechanism; Figure 12 Schematic diagram of the operation of the rotary pre-tightening mechanism. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings. The embodiments described are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. The textual descriptions in this embodiment correspond to the accompanying drawings, and the descriptions of the directions are also based on the descriptions of the accompanying drawings, and should not be construed as limiting the scope of protection of the present invention.

[0026] like Figure 1 As shown, a coupling pre-tightening machine is characterized by comprising a coupling feeding mechanism 1, a robotic arm 2, an operating tool 3, a pre-tightening trolley 4, a rotating pre-tightening mechanism 5 and a visual recognition mechanism.

[0027] The coupling feeding mechanism 1 comprises a storage frame 101 and a feeding chute 102. The storage frame is used to store couplings. The front end of the feeding chute begins at the storage frame, and the rear end is lower than the front end and is equipped with a retaining plate 103. Workers move couplings onto the feeding chute, and the couplings roll down the chute to the retaining plate, which serves as the material retrieval position for the robotic arm. The feeding chute has a downward slope of 10°. A fixed side plate 104 is provided on one side of the feeding chute 102, and a movable side plate 105 is provided on the other side. The movable side plate 105 can be moved relative to the fixed side plate 104 to accommodate couplings of different specifications.

[0028] like Figure 3-5 As shown, the work tool 3 is installed on the robot arm 3. The work tool has a material picking handle 303 and an elastic gripping clamp. The material picking handle 303 lifts the coupling horizontally. In order to avoid scratching the coupling, a rubber sleeve is covered on the material picking handle 303. The elastic gripping clamp is used to clamp the handle of the pre-tightening trolley, and then the robot arm pushes the pre-tightening trolley to move forward and backward relative to the pipe body. The work tool 3 includes a parts sleeve 301, a core shaft 302, and a material picking handle 303. The top of the parts sleeve 301 is provided with a flange edge, and the flange edge is connected to the robot arm by connecting bolts. The material picking handle 303 is integrally formed on the outside of the parts sleeve 301. A positioning step 304 is provided at the proximal end of the material picking handle 303 to position the coupling when picking up materials. Mandrel 302 is vertically mounted within component housing 301. The inner wall of component housing 301 features a connecting plate, through which mandrel 302 passes. A nut is secured to the top of the mandrel, allowing it to be vertically suspended from the connecting plate. Mandrel 302 is still movable relative to component housing 301. A torsion spring 304 is secured to the mandrel's surface, ensuring that mandrel 302 remains stable and resilient. The spring also acts as an axial damper. Mandrel 302 has a truncated cone, with one end of the torsion spring acting on the cone and the other on the connecting plate. The cone's dimensions match the internal dimensions of the component housing. This cone stabilizes the mandrel and prevents it from tilting when it twists or moves up and down within the component housing.

[0029] The lower end of the core shaft 302 exposes the part sleeve 301 downward, and an elastic clamp is arranged at the lower end of the core shaft 302. The structure of the elastic clamp is that a splint 305 is respectively arranged on both sides of the lower end of the core shaft 302, and the first connecting rod 306 passes horizontally through the two splints 305 and the middle core shaft 302. The two splints can move relative to each other along the first connecting rod, and at the same time, the two ends of the first connecting rod 306 form a limit for the two splints; the second connecting rod 307 passes horizontally through the two splints 305 and the middle core shaft 302, and at the same time, the two ends of the second connecting rod 307 are respectively covered with compression springs 308 (one end of the compression spring presses against the nut screwed on the second connecting rod, and the other end presses against the splint). The compression springs 308 at both ends act on the splint 305 on the same side respectively, so that the two splints 305 always have a tendency to be relatively clamped, and the thickness of the lower end of the core shaft is less than the thickness of the handle of the pre-tightened trolley.

[0030] like Figure 6-8 The pre-tightening trolley 4 includes a frame 401, a slider 402, a transverse rail 403, an electromagnetic suction cup 404, an upper seat 405, and a base 406. The sliders 402 are a pair and are arranged at the bottom of the frame 401. The frame 401 slides with the linear rail of the upper seat 405 through the slider 402, and the robotic arm pushes the frame 401 to move linearly relative to the upper seat 405. The transverse rail 403 is set on the frame 401, and the electromagnetic suction cup 404 is slidably set on the transverse rail 403 and moves laterally along the transverse rail. The linear rail is parallel to the central axis of the coupling, and the transverse rail is perpendicular to the central axis of the coupling. The surface of the electromagnetic suction cup 404 is a V-shaped groove, and the coupling falls into the V-shaped groove. A lifting cylinder 407 is set on the base 406, and the lifting cylinder 407 acts on the upper seat 405 to lift and lower relative to the base. In order to ensure smooth lifting, the upper seat is provided with multiple guide pillars 408, and the base is provided with multiple sliding sleeves correspondingly. The guide pillars are slidably arranged in the sliding sleeves one by one. The sliding sleeves include a copper sleeve 409, a graphite copper sleeve 410 and a copper sleeve cover 411. The graphite copper sleeve 410 is arranged on the inner wall of the copper sleeve 409, and the copper sleeve cover 411 is arranged at the port position of the copper sleeve 409 and the graphite copper sleeve 410. In this way, the pre-tightened trolley has a floating lifting and lowering adjustment function.

[0031] like Figure 11 、 12 The rotary pre-tightening mechanism 5 includes several groups of axially arranged rotating wheels. The pipe body pre-tightened with the coupling is supported on several groups of rotating wheels at the same time. Each group of rotating wheels includes a driving wheel and a driven wheel. The pipe body is supported on the driving wheel and the driven wheel. The driving wheel is driven to drive the pipe body and the driven wheel to rotate, thereby completing the pre-tightening with the coupling.

[0032] like Figure 9 、 10The visual recognition mechanism is to monitor the displacement of the coupling / pre-tightening trolley in combination with the camera and calculate the engagement length of the coupling and the pipe body. The camera 6 is preferably installed on the robot arm 2. During the recognition process, the ruler 7 on the edge of the electromagnetic suction cup 404 is required. The ruler 7 is fixedly set on the edge of the electromagnetic suction cup 404, and the scale of the ruler 7 is clear and can be recognized by the camera. The robotic arm operates the material picking handle to transfer the coupling to the electromagnetic suction cup (of the pre-tightening trolley at the pre-tightening starting position). After the pipe body starts to rotate, the robotic arm pushes the pre-tightening trolley from the pre-tightening starting position toward the pipe body until the coupling and the pipe body are buckled and continue to be tightened. During the tightening process, the pre-tightening trolley continues to move, and the coupling will also move relative to the electromagnetic suction cup. Wait for the robotic arm to move to the pre-set pre-tightening completion position and pause; the camera takes a picture, visually identifies the position reading of the end of the coupling, that is, the non-pre-tightening end, on the scale and calculates the comparison difference of the position readings of the coupling end before and after pre-tightening, and calculates the engagement length accordingly. If the calculated engagement length meets the design requirements of the pre-tightening screwing length, the pre-tightening is completed, and the robotic arm drives the pre-tightening trolley to reset, otherwise, an alarm is issued.

[0033] Figure 9 In the figure, a is the starting position of the pre-tightening trolley, b is the pre-tightening process, and c is the stop position of the pre-tightening trolley. The working principle of visual recognition is: Visual recognition operating conditions: Because the pre-tightening trolley's position is uncertain, the visual reference point is the steel wire, or fixed end face of the pipe. To ensure the coupling's relative travel distance can be calculated, the left end of the coupling must fall within the scale, ensuring that A is readable on the scale. Since different couplings have different lengths, H, to ensure the coupling does not contact the pipe when the robotic arm places it into the electromagnetic chuck, B must be greater than H + A. The pre-tightening trolley's travel distance, C, is calculated and set based on the minimum engagement length, h, required between the coupling and the pipe after pre-tightening.

[0034] Working Model: (1) A>S+hH and A>0 are satisfied at the same time, ensuring that the electromagnetic chuck does not exceed the steel wire before the coupling is successfully engaged, that is, the V-shaped magnet on the pre-tightening trolley does not collide with the pipe body.

[0035] (2) B>H+A, to ensure that the coupling does not collide with the pipe body when it is placed.

[0036] (3) Calculate and select the moving distance C of the pre-tightening trolley: C ≥ B- (H + A) + h, to ensure that the coupling extends out of the steel wire h; at the same time, C ≤ BS, to ensure that the V-shaped magnet does not touch the pipe body, and select a suitable distance from here.

[0037] (4) Determine whether the pre-tightening is successful: After the pre-tightening trolley completes the transfer of the coupling, the position of the coupling in the V-shaped magnet is read on the ruler to determine whether the pre-tightening is successful. If the pre-tightening is successful, the actual engagement length should be greater than the minimum engagement length h, that is, D+C+HB≥h, that is, D≥B+hCH.

[0038] For example: coupling length H=400mm, S=380mm, pre-tightened engagement length h=50mm Steps: ① Determine A: A>S-H+h, that is, A>380+50-400, A>30, select A=50.

[0039] ② Determine B: B>H+A, that is, B>400+50, B>450, select B=480.

[0040] ③ Determine C: C≥B-(H+A)+h, that is, C≥480-(400+50)+50, C≥80; C≤BS, that is, C≤480-380, C≤100, select C=90mm.

[0041] ④Verification is based on D≥B+hCH, that is, D≥480+50-90-400, D≥40 (pre-tightening successful), D<40 pre-tightening unsuccessful (alarm).

[0042] The action flow is: 1. Preparation: The operator places the couplings on the temporary storage stand into the loading chute with an inclined angle one by one. The couplings can automatically roll down to the bottom robotic arm material taking position and the baffle plate position.

[0043] 2. The robotic arm automatically moves the coupling from the coupling loading chute to the electromagnetic chuck using the work tooling based on the positioning, including the loading chute material positioning and the electromagnetic chuck positioning.

[0044] 3. After the coupling falls into the electromagnetic chuck, the electromagnetic chuck is energized to generate magnetism to hold the coupling.

[0045] 4. The robotic arm moves to remove the work tool from the coupling.

[0046] 5. The robotic arm continues to move, and according to the positioning, the working tool is clamped on the handle of the pre-tightening trolley 8. The robotic arm pauses and waits.

[0047] 6. When the pipe body reaches the pre-tightening station and the pipe mouth reaches the steel line, multiple pairs of rotating wheels axially support the pipe body, and the rotating wheels drive the pipe body to rotate.

[0048] 7. After the pipe body starts to rotate, the robotic arm pushes the pre-tightening trolley 7 close to the pipe body according to the set speed, the coupling and the pipe body are buckled and continue to be tightened. The robotic arm moves to the preset coupling pre-tightening completion position, completing the set displacement distance and pausing the action.

[0049] 8. The camera installed on the robotic arm takes pictures and uses visual recognition technology to calculate the engagement length based on the position change difference of the coupling end on the ruler. If the engagement length meets the set requirements, the robotic arm will move and drive the pre-tightening trolley back to the ready position. Otherwise, the equipment will alarm and the operator will intervene to handle it.

[0050] 9. The device enters the next action cycle.

[0051] In addition to the above embodiments, the present invention also includes other implementation methods. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of protection of the claims of the present invention.

Claims

1. A coupling pre-tightening machine, characterized in that: The present invention comprises a coupling feeding mechanism, a robotic arm, an operating tool, a pre-tightening trolley, a rotating pre-tightening mechanism and a visual recognition mechanism, wherein the coupling feeding mechanism comprises a material storage frame and a loading trough, the loading trough has a coupling picking station, the operating tool is installed on the robotic arm, the operating tool has a picking handle and an elastic gripping clamp, the pre-tightening trolley has an electromagnetic suction cup for supporting the coupling, the picking handle moves the coupling from the loading trough to the electromagnetic suction cup under the drive of the robotic arm, the elastic gripping clamp grabs the handle of the pre-tightening trolley, the pre-tightening trolley is moved forward and backward relative to the axial direction of the pipe body under the drive of the robotic arm, the pre-tightening trolley has a floating lifting and lowering adjustment mechanism, the rotating pre-tightening mechanism comprises several groups of axially arranged rotating pairs of wheels, the pipe body pre-tightened with the coupling is supported on several groups of the rotating pairs of wheels, the rotating pairs of wheels are driven to drive the pipe body to rotate and complete pre-tightening with the coupling, and the visual recognition mechanism is used to monitor and calculate the meshing length of the pipe body and the coupling.

2. The coupling pre-tightening machine according to claim 1, characterized in that: The front end of the feeding chute of the coupling feeding mechanism starts from the material storage frame, the end height is lower than the front end and a material baffle is provided. The downslope angle of the feeding chute is 10°. A fixed side plate is provided on one side and a movable side plate is provided on the other side of the two sides of the feeding chute. The movable side plate can adjust the distance relative to the fixed side plate.

3. The coupling pre-tightening machine according to claim 1, characterized in that: The electromagnetic chuck has a V-shaped groove, and the coupling falls into the V-shaped groove.

4. The coupling pre-tightening machine according to claim 1, characterized in that: The working tooling includes a part sleeve, a core shaft, and a material picking handle. A flange edge is provided at the top of the part sleeve, and the flange edge is connected to the robotic arm through a connecting bolt; the material picking handle is formed on the outside of the part sleeve, and a positioning step is provided at the proximal end of the material picking handle; the core shaft is vertically arranged in the part sleeve, and the upper end of the core shaft is suspended on the part sleeve and can rotate freely relative to the part sleeve. A torsion spring is provided on the surface of the core shaft, and the core shaft always has a tendency to rotate and reset due to the restriction of the torsion spring. The core shaft has a frustum, and one end of the torsion spring acts on the frustum. The size of the frustum coincides with the internal size of the part sleeve; the lower end of the core shaft is exposed from the part sleeve, and the elastic gripper is provided at the lower end of the core shaft.

5. The coupling pre-tightening machine according to claim 1, characterized in that: The surface of the material taking handle is covered with a rubber sleeve.

6. The coupling pre-tightening machine according to claim 4, characterized in that: The structure of the elastic clamp is that splints are respectively arranged on both sides of the lower end of the core shaft, and the first connecting rod passes horizontally through the two splints and the middle core shaft, and the two splints can move relative to each other along the first connecting rod, and at the same time, the two ends of the first connecting rod form a limit for the two splints; the second connecting rod passes horizontally through the two splints and the middle core shaft, and at the same time, the two ends of the second connecting rod are respectively covered with compression springs, and the compression springs at both ends act on the splints on the same side respectively, so that the two splints always have a tendency to clamp relatively, and the thickness of the lower end of the core shaft is less than the thickness of the handle of the pre-tightened trolley.

7. The coupling pre-tightening machine according to claim 1, characterized in that: The pre-tightening trolley includes a frame, a slider, a transverse rail and an electromagnetic suction cup. The slider is arranged at the bottom of the frame, and the slider slides with the linear rail of the upper seat. The transverse rail is arranged on the frame, and the electromagnetic suction cup is slidably arranged on the transverse rail. The linear rail is parallel to the central axis of the coupling, and the transverse rail is perpendicular to the central axis of the coupling.

8. The coupling pre-tightening machine according to claim 7, characterized in that: The pre-tightening trolley also includes a base, a lifting cylinder is provided on the base, and the lifting cylinder acts on the upper seat to lift and lower relative to the base. The upper seat is provided with multiple guide pillars, and the base is correspondingly provided with multiple sliding sleeves. The guide pillars are slidably arranged in the sliding sleeves one by one. The sliding sleeve includes a copper sleeve, a graphite copper sleeve and a copper sleeve cover. The graphite copper sleeve is arranged on the inner wall of the copper sleeve, and the copper sleeve cover is arranged at the port position of the copper sleeve and the graphite copper sleeve.

9. The coupling pre-tightening machine according to claim 1, characterized in that: The visual recognition mechanism is to monitor the displacement of the coupling and the pre-tightening trolley in combination with a camera and calculate the engagement length of the coupling and the pipe body. The camera is installed on a robotic arm. During the recognition process, it is necessary to use the ruler on the edge of the electromagnetic suction cup. The ruler is fixedly set on the edge of the electromagnetic suction cup, and the scale is clear and can be monitored by the camera; the robotic arm operates the material picking handle to transfer the coupling to the electromagnetic suction cup. After the rotation of the pipe body starts, the robotic arm pushes the pre-tightening trolley from the pre-tightening starting position to the pipe body. The coupling and the pipe body are buckled and continue to be tightened. The robotic arm pauses when it moves to the pre-set pre-tightening completion position; the camera takes a picture and uses visual recognition to read the position of the end of the coupling, that is, the non-pre-tightening end, on the ruler and calculate the comparison difference of the position readings of the end of the coupling before and after pre-tightening, and calculates the engagement length accordingly. If the engagement length meets the design requirements of the pre-tightening screwing length, the pre-tightening is completed, and the robotic arm drives the pre-tightening trolley to reset, otherwise, an alarm is issued.

10. The coupling pre-tightening machine according to claim 9, characterized in that: The identification method of the visual identification mechanism and the calculation method of the meshing length are as follows: the end face of the steel wire, i.e., the pre-tightening end of the pipe body, is used as the reference point. In order to ensure that the moving distance of the coupling on the electromagnetic chuck can be monitored, the end of the coupling during the entire pre-tightening process must fall within the measuring range of the scale; when the pre-tightening trolley stops at the pre-tightening starting position, the distance reading between the position of the coupling end on the scale relative to the starting end of the scale is recorded as A, and the distance between the starting end of the scale and the steel wire is recorded as B; after the pre-tightening trolley reaches the pre-tightening completion position, the moving distance of the pre-tightening trolley is recorded as C, and the distance reading between the position of the coupling end on the scale relative to the starting end of the scale is recorded as D. In order to ensure the smooth implementation of the pre-tightening process and the identification and monitoring of the implementation process, the following conditions must be met: A>S+hH, and A>0; B>H+A; B-(H+A)+h ≤C≤BS, where H is the coupling length, S is the scale length, and h is the shortest engagement length. Within this range, a suitable moving distance is set for the pre-tightening trolley. After the pre-tightening trolley has completed the set moving distance, D is used to determine whether the pre-tightening is in place. The determination method is: the actual engagement length should be greater than the minimum engagement length, D+C+HB≥h.

Images