Oil well pipe external thread detection device

Abstract

The invention relates to the technical field of thread detection, in particular to an oil well pipe external thread detection device which comprises a tensioning mechanism, a detection mechanism, a first supporting frame and a second supporting frame, the tensioning mechanism is arranged on the first supporting frame, and the detection mechanism comprises a first lead screw, a first nut, a fixing base, a first gear, a first transmission belt, a second gear and a second transmission belt. The device can realize a clamping function on tubular structures such as an oil well pipe, and because the diameter of the tensioning mechanism can be changed from small to large, the device can adapt to tubular structures of various sizes instead of being only suitable for tubular structures of one size, a projection image detector is installed on the fixed seat, accurate detection on threads can be realized, and the detection precision is improved. And the projection image detector can be replaced at any time due to the detachable design, so that the service life is prolonged, and the maintenance and use cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of thread detection, in particular to an oil well pipe external thread detection device. Background Art

[0002] Oil well pipe thread processing is a highly precise technology with tolerance requirements at the micron level. Due to the complex shape and structure, and the many inspection parameters involved, a large number of special measuring tools are required. This places extremely high demands on the skill level of the operators, who need to have rich practical experience and superb technical level to ensure that each thread can achieve a 100% pass rate.

[0003] However, the current method of thread measurement still mainly relies on manual measurement and random inspection, and the random inspection ratio is usually between 10% and 20%. This measurement method is actually a compromise between manufacturers in terms of equipment and personnel configuration. Although it has certain feasibility in actual operation, it cannot fully meet the quality assurance requirements. Because once a quality problem occurs, the manufacturer not only needs to compensate for the product, but also needs to bear the resulting engineering losses. Summary of the invention

[0004] The object of the present invention is to provide an oil well pipe external thread detection device to solve the problems raised in the above background technology.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an oil well pipe external thread detection device comprises: a tensioning mechanism, a detection mechanism, a first support frame, and a second support frame, wherein the first support frame is fixedly arranged on the ground, and the panel is arranged perpendicular to the ground, the tensioning mechanism is arranged on the panel of the first support frame, the tensioning mechanism comprises a tensioning block, a connecting part, and a control component, a plurality of tensioning blocks form an arc-shaped facade of a cylinder, a connecting part is arranged on the inner surface of the tensioning block, the tensioning block is fixedly connected to the control component through the connecting part, and the tensioning block is tightened outwardly through the control component, the second support frame is arranged on the ground on the side of the first support frame away from the tensioning mechanism, and the panel is arranged perpendicular to the ground, the detection mechanism is arranged on the panel of the second support frame, the detection mechanism comprises a first lead screw, a first nut, a fixing seat, a first gear, a first transmission belt, a second gear, and a second transmission belt, a plurality of lead screw brackets and a plurality of gear brackets are arranged on the second support frame, and the lead screw bracket and the gear bracket are perpendicular to the panel of the second support frame, and slots are arranged on both sides of the panel of the first support frame so that the lead screw bracket can pass through the first support frame and extend to the first support frame panel to set the tensioning On one side of the mechanism, a bearing is provided on the screw bracket, and the screw bracket is rotatably connected to the first screw through the bearing, each first screw is respectively connected to the two screw brackets, a bearing is provided on the gear bracket, and the gear bracket is rotatably connected to the second gear through the bearing, and each second gear is respectively connected to the two gear brackets, two first screws are provided in the detection mechanism, the first screw is arranged perpendicular to the ground, the two first screws are respectively arranged on both sides of the tensioning mechanism, two groups of threads in opposite directions are respectively arranged at both ends of the first screw, a first nut is arranged on each group of threads, a fixing seat is arranged on each first nut, a detachable projection image detector is arranged on the fixing seat, and two projection image detectors located on the same side of the two first screws are arranged oppositely, a first gear is provided in the middle of the first screw, and a second gear is provided on the side close to the second support frame, the first gear and the second gear are connected by a first transmission belt, the second gear tooth width is wider than the first gear, the two second gears are connected by a second transmission belt, and a second gear is also provided in the middle of the second transmission belt, and this second gear drives the second transmission belt to move, and it is driven by a motor.

[0006] Furthermore, the control component includes a first rotating shaft, a fixed rod, a connecting rod, a sliding block, a sliding rail, and a second rotating shaft. The control component is arranged inside the arc-shaped outer facade of the cylinder formed by the tensioning block. The first rotating shaft is arranged at the center of the control component. The second rotating shaft is hollow inside. The first rotating shaft is placed in the second rotating shaft. The two ends of the first rotating shaft are respectively arranged at the center of the two end surfaces of the second rotating shaft. The first rotating shaft is rotatably connected to the second rotating shaft through bearings. A motor is built into the second rotating shaft to drive the first rotating shaft. The first rotating shaft control component is arranged inside the arc-shaped outer facade of the cylinder formed by the tensioning block. The first rotating shaft is arranged at the center of the control component. The second rotating shaft is hollow inside. The first rotating shaft is placed in the second rotating shaft. The two ends of the first rotating shaft are respectively arranged at the center of the two end surfaces of the second rotating shaft. The second rotating shaft is rotatably connected to the second rotating shaft through bearings. The first rotating shaft is internally provided with a motor to drive the first rotating shaft, and the first rotating shaft is fixedly connected with the same number of fixed rods as the tensioning blocks, each of which is respectively connected to one end of a connecting rod, and the other end of the connecting rod is fixedly connected to the connecting part, and the same number of fixed rods as the tensioning blocks are fixedly connected to the upper part, each of which is respectively connected to one end of a connecting rod, and the other end of the connecting rod is fixedly connected to the connecting part, and a slider and a slide rail are arranged on the connecting rod, and the slider is arranged at one end of the connecting rod close to the tensioning block, and is restricted to move on the slide rail, and the second rotating shaft is provided with a slot on the fixed rod and the movement track of the connecting rod, and the slide rail is arranged on the outer surface of the second rotating shaft, and a gap is left between its bottom surface and the first support frame panel, and the direction of the slide rail is the projection formed on the first support frame panel by the line connecting the center of the corresponding tensioning block to the first rotating shaft. The projection formed.

[0007] Furthermore, a bearing is provided at one end of the second rotating shaft, which is rotatably connected to the upper surface of the first support frame through the bearing, and a motor is also provided inside the second rotating shaft to drive the second rotating shaft to rotate.

[0008] Furthermore, a second lead screw is arranged on a side of the second support frame away from the first support frame. The second lead screw is perpendicular to the upper surface of the second support frame, and its upper end is arranged at its center and is connected to the second support frame through a bearing. The lower end of the second lead screw is threadedly connected to the nut base.

[0009] Furthermore, a connecting frame is provided below the second support frame, a pulley is provided below the connecting frame, an extension rod is provided below the first lead screw, the extension rod is connected to the first lead screw through a bearing, a pulley is fixedly connected below the extension rod, a plurality of slide rails are provided on the ground, the position of the slide rails is lower than the vertical height of the ground, each pulley is restricted to move within a slide rail, and the slide rail is perpendicular to the projection of the second support frame on the ground.

[0010] Furthermore, the first lead screw and the second lead screw are both designed as trapezoidal lead screws, and the corresponding first nut and nut base have matching threads.

[0011] Furthermore, a rubber layer is provided on the outer surface of the tensioning block.

[0012] Compared with the prior art, the present invention has the following advantages: (1) The present invention drives the tensioning block through the control component in the tensioning mechanism, so as to realize the clamping function of tubular structures such as oil well pipes. Moreover, because the tensioning mechanism can realize the change of diameter from small to large, the present invention can adapt to tubular structures of various sizes, rather than only one size.

[0013] (2) The present invention has a detachable projection image detector installed on the fixed seat. The projection image detector arranged opposite to each other can realize accurate detection of the thread, and the detachable design can replace the projection image detector at any time, thereby increasing the service life of the present invention and reducing the maintenance and use costs.

[0014] (3) The present invention enables the projection image detector disposed on the fixed seat to move in opposite directions on the first lead screw through the mutual cooperation between the first lead screw and the first nut, so as to adapt to tubular structures of different sizes. That is, when the diameter of the tubular structure is large, the first nut will move to a position opposite to the end of the first lead screw; when the diameter of the tubular structure is small, the first nut will move to a position relatively close to the center of the first lead screw, thereby cooperating with the tensioning mechanism to detect external threads on tubular structures of different sizes.

[0015] (4) The second rotating shaft in the tensioning mechanism of the present invention can drive the tensioning mechanism to rotate along its axis, so that during inspection, after the tensioning mechanism tensions the tubular structure and the projection image detector completes this section of inspection, the tensioning mechanism drives the tubular structure to rotate, placing the other part of the threaded portion that has not been inspected within the inspection range of the projection image detector to achieve all-round inspection, thereby maximizing the inspection accuracy.

[0016] (5) The present invention can drive the overall displacement of the second support frame through the second lead screw and the nut base, and at the same time can drive the projection image detector set on the fixed base to move horizontally. This design enables the projection image detector to detect the effect of threads at different lengths. When the thread length on some tubular structures is long, the projection image detector cannot detect all of its threads at a fixed position. The projection image detector that can move up and down solves this technical problem, realizes fully automatic detection, and greatly improves the accuracy and efficiency of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a device for detecting external threads of oil well pipes.

[0018] Figure 2 Perspective diagram of the testing mechanism.

[0019] Figure 3 Schematic diagram of the tensioning mechanism.

[0020] Figure 4 Schematic diagram of the tensioning mechanism after tightening.

[0021] Among them, 100, tensioning mechanism, 110, tensioning block, 111, connecting part, 120, control component, 121, first rotating shaft, 122, fixing rod, 123, connecting rod, 1231, slider, 1232, slide rail, 130, second rotating shaft, 200, detection mechanism, 210, first lead screw, 220, first nut, 221, fixing seat, 230, first gear, 240, first transmission belt, 250, second gear, 260, second transmission belt, 300, first supporting frame, 310, supporting column, 320, top plate slot, 400, second supporting frame, 410, second lead screw, 420, nut base, 430, lead screw bracket, 440, gear bracket, 500, slide rail, 510, pulley. DETAILED DESCRIPTION

[0022] The present invention aims to address the deficiencies of the prior art and provide an oil well pipe external thread detection device, which is specifically implemented by the following technical solutions: Reference Figure 1 An oil well pipe external thread detection device includes: a tensioning mechanism 100, a detection mechanism 200, a first support frame 300, and a second support frame 400, wherein the tensioning mechanism 100 is arranged on a panel of the first support frame 300.

[0023] Reference Figure 3 , Figure 4 The tensioning mechanism 100 includes a tensioning block 110, a connecting portion 111, and a control assembly 120. A plurality of tensioning blocks 110 form an arc-shaped facade of a cylinder. The arc-shaped facade enables the tensioning block 110 to adapt to the curvature of the inner surface of the tubular structure. Regardless of the diameter of the tubular structure, as long as its diameter is between the minimum diameter and the maximum diameter of the tensioning mechanism 100, the tubular structure can be tensioned by the tensioning mechanism 100, thereby greatly enhancing the applicability of the detection device.

[0024] Reference Figure 3 , Figure 4 The inner surface of the tension block 110 is provided with a connecting portion 111, and the tension block 110 is fixedly connected to the control assembly 120 through the connecting portion 111. A certain distance is left between the end of the connecting portion 111 and the tension block 110 to facilitate the movement of the control assembly 120, so that the end of the connecting rod 123 will not hit the inner surface of the tension block 110 during movement, and the tension block 110 is tightened outwards through the control assembly 120. Figure 3 , Figure 4The control component 120 includes a first rotating shaft 121, a fixed rod 122, a connecting rod 123, a slider 1231, a slide rail 1232, and a second rotating shaft 130. The control component 120 is arranged inside the arc-shaped facade of the cylinder formed by the tensioning block 110. The first rotating shaft 121 is arranged at the center of the control component 120. The second rotating shaft 130 is hollow inside. The first rotating shaft 121 is placed in the second rotating shaft 130. The two ends of the first rotating shaft 121 are respectively arranged at the center of the two end surfaces of the second rotating shaft 130, and are rotatably connected to the second rotating shaft 130 through bearings. A motor is built into the second rotating shaft 130 to drive the first rotating shaft 121. The first rotating shaft 121 is fixedly connected with the same number of fixed rods 122 as the tensioning block 110. Each fixed rod 122 is connected to one end of a connecting rod 123, and the other end of the connecting rod 123 is fixedly connected to the connecting part 111. A slider 1231 and a slide rail 1232 are provided on the connecting rod 123. The slider 1231 is arranged at one end of the connecting rod 123 close to the tensioning block 110, and is restricted to move on the slide rail 1232. The second rotating shaft 130 is provided with a slot on the movement trajectory of the fixed rod 122 and the connecting rod 123. The slide rail 1232 is arranged on the outer surface of the second rotating shaft 130, and a gap is left between its bottom surface and the panel of the first support frame 300. The direction of the slide rail 1232 is the projection of the line connecting the center of the corresponding tensioning block 110 to the first rotating shaft 121 formed on the panel of the first support frame 300. After the first rotating shaft 121 rotates, the fixed rod 122 rotates synchronously with the first rotating shaft 121 , and the fixed rod 122 drives the connecting rod 123 to move. One end of the connecting rod 123 is restricted by the slider 1231 to move in the slide rail 1232 , so the tensioning block 110 can be tightened and closed under the drive of the first rotating shaft 121 . A bearing is provided on the bottom surface of the second rotating shaft 130, which is rotatably connected to the upper surface of the first support frame 300 through the bearing, and a motor is also provided inside the second rotating shaft 130 to drive the second rotating shaft 130 to rotate, so that the tensioning mechanism 100 can realize overall rotation under the drive of the second rotating shaft 130. The purpose of this design is to enable the tubular structure tightened and fixed by the tensioning mechanism 100 to realize self-rotation when it is detected by the projection image detector, thereby realizing the detection of a full circle of the external thread of the tubular structure, thereby achieving the purpose of fully automatic detection. At the same time, due to this design, the slide rail 1232 cannot be set on the panel of the first support frame 300, because the tensioning mechanism 100 will rotate as a whole. If the slide rail 1232 is set on the fixed first support frame 300, the corresponding tensioning purpose cannot be achieved. Therefore, the slide rail 1232 is separately set on the outer surface of the second rotating shaft 130, so that it moves with the tensioning mechanism 100, and its relative position with the first rotating shaft 121 will not change, thereby ensuring the normal operation of the tensioning mechanism 100.

[0025] Reference Figure 1 , Figure 2The detection mechanism 200 is arranged on the second support frame 400. The detection mechanism 200 includes a first screw 210, a first nut 220, a fixing seat 221, a first gear 230, a first transmission belt 240, a second gear 250, and a second transmission belt 260. The second support frame 400 is arranged on the ground on the side of the first support frame 300 away from the tensioning mechanism 100, and the panel is arranged perpendicular to the ground. The detection mechanism 200 is arranged on the panel of the second support frame 400. Slots are arranged on both sides of the panel of the first support frame 300 so that the screw bracket 430 can pass through the first support frame 300. The panel is arranged on one side of the tensioning mechanism 100 so that the projection image detector can be placed at the same horizontal position of the thread on the outer surface of the tubular structure. The second support frame 400 is provided with a plurality of screw brackets 430 and a plurality of gear brackets 440. The screw bracket 430 is provided with bearings. The screw bracket 430 is rotatably connected to the first screw 210 through the bearings. Each first screw 210 is respectively connected to two screw brackets 430, so that the first screw 210 can be arranged on the side of the first support frame 300 away from the second support frame 400. The gear bracket 440 is provided with bearings. The gear bracket 440 is rotatably connected to the second gear 250 through the bearings. Each second gear 250 is respectively connected to two gear brackets 440. Two first screws 210 are provided in the detection mechanism 200. The two first screws 210 are respectively arranged on both sides of the tensioning mechanism 100. Two sets of threads in opposite directions are respectively provided at both ends of the first screw 210, and each set of threads is provided with a first The nut 220 has opposite threads, so that when the first screw 210 rotates, the two first nuts 220 arranged on the threads at both ends of the first screw 210 will also move in opposite directions, that is, the two first nuts 220 will simultaneously approach or move away from the center of the first screw 210. Each first nut 220 is provided with a fixing seat 221, and a detachably mounted projection image detector is provided on the fixing seat 221. The two projection image detectors located on the same side of the two first screws 210 are arranged opposite to each other. The two projection image detectors respectively emit lasers to the other projection image detector opposite to them, so as to record the thread morphology of the line connecting the projection image detectors on the same side of the two first screws 210 of the tubular structure and the tangent of the edge of the tubular structure, and record the thread morphology through the background, so as to achieve the purpose of detecting the thread.

[0026] Reference Figure 1 , Figure 2A first gear 230 is provided in the middle of the first lead screw 210, and the first gear 230 drives the first lead screw 210 to rotate, thereby driving the projection image detector located on the first nut 220 to move in the horizontal direction, so as to adapt to tubular structures of different sizes. That is, when the diameter of the tubular structure is small, the distance between the first nuts 220 on the same first lead screw 210 is shorter, and when the diameter of the tubular structure is large, the distance between the first nuts 220 on the same first lead screw 210 is longer, so that the projection image detector can move to the edge of tubular structures of different sizes to record the shape of the thread.

[0027] Reference Figure 2 A second gear 250 is provided on one side of the first gear 230 close to the second support frame 400. The first gear 230 and the second gear 250 are connected by a first transmission belt 240. The tooth width of the second gear 250 is wider than that of the first gear 230. The two second gears 250 are connected by a second transmission belt 260. A second gear 250 is also provided in the middle of the second transmission belt 260. After the second gear 250 rotates, it drives the second transmission belt 260 to rotate, and then drives the two second gears 250 set at both ends of the second transmission belt 260 to rotate. The rotation of the two second gears 250 respectively drives the first transmission belt 240 in which they are located to rotate. The rotation of the first transmission belt 240 drives the first gear 230 to rotate, and finally drives the first lead screw 210 to rotate. The second gear 250 set in the middle of the second transmission belt 260 is driven by a motor.

[0028] Reference Figure 1 , Figure 2 A second lead screw 410 is provided on the side of the second support frame 400 away from the first support frame 300. The second lead screw 410 is perpendicular to the panel of the second support frame 400, and its upper end is arranged at its center and connected to the second support frame 400 through a bearing. One end of the second lead screw 410 is threadedly connected to the nut base 420. The second lead screw 410 is driven by a motor. After the second lead screw 410 rotates, it will move forward or backward relative to the nut base 420, thereby driving the second support frame 400 to move forward and backward as a whole, and the detection mechanism 200 arranged on the second support frame 400 can also move forward and backward. This design can enable the projection image detector to achieve the purpose of forward and backward movement, and ensure that when the length of the external thread of the tubular structure is long, the projection image detector in a fixed position cannot capture its full picture. Therefore, after the projection image detector records the state of a part of its thread, it is necessary to move the projection image detector to the undetected area for detection. This design can meet this requirement, improve the automation level of the device, and reduce the manual operation cost.

[0029] Reference Figure 1 , Figure 2A connecting frame is provided below the second support frame 400, a pulley 510 is provided below the connecting frame, an extension rod is provided below the first lead screw 210, the extension rod is connected to the first lead screw 210 through a bearing, a pulley 510 is fixedly connected below the extension rod, a plurality of slide rails 500 are provided on the ground, the slide rails 500 are located below the vertical height of the ground, each pulley 510 is restricted to move within a slide rail 500, the slide rail 500 is perpendicular to the projection of the second support frame 400 on the ground, the weight of the second support frame 400 and the first lead screw 210 is transferred to the pulley 510 through the connecting frame and the extension rod, and the pulley 510 is restricted to move within the slide rail 500, which does not affect the overall displacement of the detection mechanism 200 while ensuring the service life of the detection mechanism 200, otherwise all the weight will be supported by the second lead screw 410 and the lead screw bracket 430.

[0030] The first lead screw 210 and the second lead screw 410 are both designed with a trapezoidal lead screw, and the corresponding first nut 220 and the nut base 420 use matching threads. The trapezoidal lead screw has a self-locking function and can better complete the related work of the present invention.

[0031] The outer surface of the tension block 110 is provided with a rubber layer, which can more firmly fix the tubular structure without damaging the inner surface of the tubular structure.

[0032] Embodiment: The detector uses parallel light emission technology to measure the projection image formed by the light blocked by the parts, so as to accurately obtain the size and related data of the thread. Because the diameter range of steel pipes varies greatly, from the minimum diameter of 244.48mm to the maximum diameter of 533mm, the maximum tightening size of the tensioning mechanism 100 of the device is 580mm, the closing size is 220mm, the spacing between the two first screws 210 in the detection mechanism 200 is greater than 620mm, and the maximum distance between the first nuts 220 on the same first screw 210 is 620mm, and the minimum distance is 520mm, so that it can adapt to most sizes of tubular structures.

[0033] When in use, first, the tubular structure is covered on the outer ring of the tensioning mechanism 100 by a conveyor belt or a manipulator. Because the diameter of the tensioning mechanism 100 in the closed state is smaller than the minimum size of the tubular structure, it is very easy to cover the tubular structure on the outer ring of the tensioning mechanism 100. At this time, the detection can be started, and the motor driving the first rotating shaft 121 is turned on. At this time, the tensioning mechanism 100 is tightened outward. No matter how much the inner ring diameter of the tubular structure is, the tensioning mechanism 100 can tightly fix the tubular structure thereon. When the fixing work is completed, the motor of the second gear 250 set in the middle of the second transmission belt 260 is driven to start, and the first nut 220 is driven to move, and the projection image detector on the fixed seat is moved to the corresponding position. After completion, the motor of the second lead screw 410 is driven to start, and the projection image detector is moved Move to the required position. After the projection image detector is in place, the projection image detector starts working. At the same time, the background drive system controls the motor driving the second rotating shaft 130 to turn on and off. The tensioning mechanism 100 cooperates with the projection image detection to perform staged rotation. That is, when the projection image detection completes a part of the shooting, the tubular structure is rotated by a certain angle so that the projection image detection shoots the remaining threads until the state of a full circle of the thread is recorded. If the thread length has not been fully recorded at this time, the motor of the second lead screw 410 is turned on for the second time to drive the overall displacement of the detection mechanism 200, and the projection image detector is moved to the position of the thread that has not been detected. Repeat the previous operation until the detection is completed, and the recording process is synchronously transmitted to the background processing end. If there is a problem, an alarm is issued in time.

Claims

1. An oil well pipe external thread detection device, characterized in that: include: A tensioning mechanism (100), a detection mechanism (200), a first support frame (300), and a second support frame (400), wherein The first support frame (300) is fixedly arranged on the ground, and the panel is arranged perpendicular to the ground. The tensioning mechanism (100) is arranged on the panel of the first support frame (300). The tensioning mechanism (100) comprises a tensioning block (110), a connecting portion (111), and a control assembly (120). A plurality of tensioning blocks (110) form an arc-shaped outer surface of a cylinder. The inner surface of the tensioning block (110) is provided with a connecting portion (111). The tensioning block (110) is fixedly connected to the control assembly (120) via the connecting portion (111). The tensioning block (110) is tensioned outwards via the control assembly (120). The second support frame (400) is arranged on the ground at a side of the first support frame (300) away from the tensioning mechanism (100), and the panel is arranged perpendicular to the ground. The detection mechanism (200) is arranged on the panel of the second support frame (400). The detection mechanism (200) comprises a first lead screw (210), a first nut (220), a fixing seat (221), a first gear (230), a first transmission belt (240), a second gear (250), and a second transmission belt (260). The second support frame (400) is provided with a plurality of screw supports (430) and a plurality of gear supports (440), and the screw supports (430) and the gear supports (440) are perpendicular to the panel of the second support frame (400). Slots are provided on both sides of the panel of the first support frame (300), so that the screw supports (430) can pass through the first support frame (300) and extend to one side of the panel of the first support frame (300) where the tensioning mechanism (100) is provided. A bearing is provided on the lead screw support (430), and the lead screw support (430) is rotatably connected to the first lead screw (210) via the bearing, and each first lead screw (210) is respectively connected to two lead screw supports (430). A bearing is provided on the gear bracket (440), and the gear bracket (440) is rotatably connected to the second gear (250) via the bearing. Each second gear (250) is respectively connected to two gear brackets (440). Two first lead screws (210) are provided in the detection mechanism (200), the first lead screws (210) are arranged perpendicular to the ground, the two first lead screws (210) are respectively arranged on both sides of the tensioning mechanism (100), two sets of threads in opposite directions are respectively arranged at both ends of the first lead screw (210), each set of threads is provided with a first nut (220), each first nut (220) is provided with a fixing seat (221), a detachably mounted projection image detector is provided on the fixing seat (221), and the two projection image detectors located on the same side of the two first lead screws (210) are arranged facing each other, A first gear (230) is disposed in the middle of the first lead screw (210), and a second gear (250) is disposed on a side thereof close to the second support frame (400). The first gear (230) and the second gear (250) are connected via a first transmission belt (240). The tooth width of the second gear (250) is wider than that of the first gear (230); the two second gears (250) are connected via a second transmission belt (260); a second gear (250) is further arranged in the middle of the second transmission belt (260); the second gear (250) drives the second transmission belt (260) to move, and the second gear (250) is driven by a motor.

2. The oil well pipe external thread detection device according to claim 1, characterized in that: The control assembly (120) comprises a first rotating shaft (121), a fixing rod (122), a connecting rod (123), a sliding block (1231), a sliding rail (1232), and a second rotating shaft (130). The control component (120) is arranged inside the arc-shaped outer surface of the cylinder formed by the tensioning block (110). A first rotating shaft (121) is arranged at the center of the control component (120). The second rotating shaft (130) is hollow inside. The first rotating shaft (121) is placed in the second rotating shaft (130). The two ends of the first rotating shaft (121) are respectively arranged at the center of the two end surfaces of the second rotating shaft (130). The first rotating shaft (121) is rotatably connected to the second rotating shaft (130) through bearings. A motor is built into the second rotating shaft (130) to drive the first rotating shaft (121). The first rotating shaft (121) is fixedly connected to the same number of fixing rods (122) as the tensioning block (110). Each fixing rod (122) is respectively connected to one end of a connecting rod (123). The other end of the connecting rod (123) is fixedly connected to the connecting portion (111). The connecting rod (123) is provided with a slider (1231) and a slide rail (1232). The slider (1231) is provided at one end of the connecting rod (123) close to the tension block (110) and is restricted to move on the slide rail (1232). The second rotating shaft (130) is provided with a slot on the movement track of the fixed rod (122) and the connecting rod (123). The slide rail (1232) is arranged on the outer surface of the second rotating shaft (130), and a gap is left between its bottom surface and the panel of the first support frame (300). The direction of the slide rail (1232) is the projection of the line between the center of the corresponding tension block (110) and the first rotating shaft (121) formed on the panel of the first support frame (300).

3. The oil well pipe external thread detection device according to claim 2, characterized in that: A bearing is provided at one end of the second rotating shaft (130), which is rotatably connected to the upper surface of the first support frame (300) via the bearing, and a motor is also provided inside the second rotating shaft (130) for driving the second rotating shaft (130) to rotate.

4. An oil well pipe external thread detection device according to claim 1, 2 or 3, characterized in that: A second lead screw (410) is arranged on a side of the second support frame (400) away from the first support frame (300); the second lead screw (410) is perpendicular to the upper surface of the second support frame (400), and its upper end is arranged at the center thereof, and is connected to the second support frame (400) via a bearing. The lower end of the second lead screw (410) is threadedly connected to the nut base (420).

5. The oil well pipe external thread detection device according to claim 4, characterized in that: A connecting frame is provided below the second supporting frame (400), and a pulley (510) is provided below the connecting frame. An extension rod is provided below the first lead screw (210), the extension rod is connected to the first lead screw (210) via a bearing, and a pulley (510) is fixedly connected below the extension rod. A plurality of slide rails (500) are provided on the ground. The slide rails (500) are located below the vertical height of the ground. Each pulley (510) is restricted to move within a slide rail (500). The slide rail (500) is perpendicular to the projection of the second support frame (400) on the ground.

6. The oil well pipe external thread detection device according to claim 5, characterized in that: The first lead screw (210) and the second lead screw (410) both adopt a trapezoidal lead screw design, and the corresponding first nut (220) and nut base (420) adopt matching threads.

7. The oil well pipe external thread detection device according to claim 1, characterized in that: The outer surface of the tensioning block (110) is provided with a rubber layer.

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