A thread measuring device for detecting oil drill pipe joints

Abstract

The present invention complies with the technical field of thread measuring devices, and in particular, relates to a thread measuring device for detecting oil drill pipe joints. It comprises a main body, the main body is slidably connected to a sliding ring, the sliding ring is rotatably connected to a rotating shaft, the rotating shaft is fixedly connected to a threaded barrel, the sliding ring is fixedly connected to a motor, the main body is rotatably connected to a rotating ring, the rotating ring is fixedly connected to a contact block, the main body is fixedly connected to a first fixed shell, the first fixed shell is slidably connected to a first sliding rod, the first sliding rod is fixedly connected to a contact piece, and the contact piece is extruded and matched with the contact block. The present invention makes the contact block contact with the contact piece after the threads of the threaded barrel and the drill pipe joint are aligned, so as to make the motor work, screw the threaded barrel into the threads of the drill pipe joint, and thus measure the threads of the drill pipe joint, avoiding the threaded barrel starting to screw in without being aligned with the threads of the drill pipe joint, and preventing the threaded barrel from being worn, resulting in reduced accuracy or even damage.

Description

Technical Field

[0001] The invention belongs to the technical field of thread measuring devices and discloses a thread measuring device for detecting oil drill pipe joints. Background Art

[0002] The oil drill pipe is a slender member of a fixed length. As the drilling depth increases, the oil drill pipe must be continuously connected to the required length with the oil drill pipe joint. The connection structure between the oil drill pipe and the oil drill pipe joint is a threaded connection structure. The threaded connection structure rotates under high load and complex working conditions. It must not only seal the connection, but also transmit the high-power torque during drilling and bear the weight of the connection. Therefore, there are strict shape and position accuracy requirements for the oil drill pipe joint, especially the internal thread close distance of the oil drill pipe joint has extremely high accuracy requirements. Therefore, after the oil drill pipe leaves the factory, it is an indispensable step to measure the thread at the drill pipe joint. When measuring with the existing thread plug gauge, the thread plug gauge is screwed into the thread of the drill pipe joint by rotating the thread plug gauge, and the thread of the drill pipe joint is judged by observing whether the thread plug gauge can be smoothly screwed into the thread of the drill pipe joint. However, when measuring in this way, the thread plug gauge often starts to rotate when the thread of the drill pipe joint is not aligned, which will cause greater wear to the thread plug gauge, reduce the accuracy of the thread plug gauge, and even damage the thread plug gauge. Summary of the invention

[0003] In order to overcome the shortcomings mentioned in the above background technology, the present invention provides a thread measuring device for detecting oil drill pipe joints.

[0004] The technical scheme is: a thread measuring device for detecting oil drill pipe joints, comprising a main body, a sliding ring is slidably connected to one side of the main body, the sliding ring is rotatably connected to a rotating shaft through a mounting frame, the rotating shaft is fixedly connected to a threaded barrel, the sliding ring is fixedly connected to a motor through a mounting frame, the output shaft of the motor is fixedly connected to a symmetrically distributed first baffle, the output shaft of the motor is slidably connected to a symmetrically distributed second baffle, the second baffle is pressed and matched with the adjacent first baffle, the symmetrically distributed second baffles are jointly fixedly connected to a rotating shell, the rotating shell and the rotating shaft are driven by a gear set, the main body is rotatably connected to a rotating ring, the rotating ring is fixedly connected to a contact block, the contact block is slidably connected to the main body and penetrates it, the outer side of the main body is fixedly connected to a first fixed shell, the first fixed shell is slidably connected to a first sliding rod on one side close to the contact block, the first sliding rod is fixedly connected to a contact piece on one side away from the first fixed shell, the contact piece is pressed and matched with the contact block, and one of the wires forming a loop with the motor is divided into two sections, one section is connected to the contact block, and the other section is connected to the contact piece.

[0005] Furthermore, the contact piece is made of elastic metal material, so as to ensure a stable connection between it and the contact block.

[0006] Furthermore, a support frame evenly distributed in the circumferential direction is fixedly connected in the main body, and the support frame is slidably matched with the threaded barrel.

[0007] Furthermore, the length of the support frame along the axial direction of the threaded barrel is greater than the pitch of the threaded barrel, so as to enable the threaded barrel to move stably.

[0008] Furthermore, the main body is slidably connected with locking pieces that are evenly distributed circumferentially, and the locking pieces penetrate the inner side of the main body. Springs are arranged between the locking pieces that are evenly distributed circumferentially and the main body, and the rotating ring is provided with limiting grooves that are evenly distributed circumferentially. The locking pieces are limitedly matched with adjacent limiting grooves on the rotating ring, and the locking pieces are provided with unlocking grooves for allowing the rotating ring to pass.

[0009] Furthermore, the main body is provided with sliding grooves evenly distributed in the circumferential direction, and a fixing rod is slidably connected in the sliding groove. The fixing rod penetrates the inner side of the main body, and the fixing rod is used to fix the main body.

[0010] Furthermore, the main body is fixedly connected with a second fixed shell evenly distributed circumferentially, the second fixed shell is slidably connected with a second sliding rod, the second sliding rod evenly distributed circumferentially is fixedly connected to the rotating ring, and a spring is arranged between the second sliding rod and the second fixed shell.

[0011] Furthermore, the fixed rod is composed of a round rod and a disc, the disc is slidably connected to the sliding groove, the round rod penetrates the main body, the sliding groove is located on the side of the disc close to the round rod and is filled with liquid, the second sliding rod and the second fixed shell are filled with liquid, the second fixed shell is connected to the adjacent sliding groove through a hose, and the hose is located in the wall of the main body.

[0012] Furthermore, the outer side of the main body is slidably connected to a limiting member via a mounting plate, a spring is arranged between a side of the mounting plate close to the contact block and the limiting member, and the contact block is provided with a limiting groove that cooperates with the limiting member.

[0013] Furthermore, an annular shell is included, which is fixed to a side of the sliding ring close to the rotating shell, the annular shell is rotatably connected to the rotating shell, the rotating shell is provided with symmetrically distributed through holes, the symmetrically distributed first baffles, the symmetrically distributed second baffles, the rotating shell and the output shaft of the motor together form a uniformly distributed cavity, the cavity adjacent to the through hole on the rotating shell is filled with liquid, the first fixed shell and the first sliding rod are filled with liquid and provided with a tension spring, and the annular shell is connected to the first fixed shell through a hose.

[0014] The present invention has the following advantages: after the threads of the threaded barrel and the drill rod joint are aligned, the contact block contacts the contact piece, thereby operating the motor and screwing the threaded barrel into the threads of the drill rod joint, thereby measuring the threads of the drill rod joint, avoiding the threaded barrel starting to be screwed in without being aligned with the threads of the drill rod joint, and preventing the threaded barrel from being worn, resulting in reduced accuracy or even damage.

[0015] The drill pipe joint is clamped by fixing rods evenly distributed around the circumference, so as to prevent the device from being skewed or shaken during operation, thereby preventing measurement errors caused by the shaking of the device.

[0016] The contact block is limited by a limiting piece to prevent the contact block from affecting the measurement with the contact piece during the operation of the device.

[0017] When the threaded barrel encounters an obstacle during the process of being screwed into the thread of the drill pipe joint, the contact block is separated from the contact piece, thereby preventing the threaded barrel from being screwed in further and causing damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0019] Figure 2 It is a three-dimensional structural cross-sectional view of the main body of the present invention;

[0020] Figure 3 It is a schematic diagram of the three-dimensional structure of the sliding ring and the rotating shaft of the present invention;

[0021] Figure 4 It is a three-dimensional structural cross-sectional view of the rotating shaft, the rotating shell and the annular shell of the present invention;

[0022] Figure 5 It is a three-dimensional structural cross-sectional view of the rotating shell of the present invention;

[0023] Figure 6 It is a schematic diagram of the three-dimensional structure of the first fixed shell and the first sliding rod of the present invention;

[0024] Figure 7 An exploded view of the rotating ring, the contact block and the locking member of the present invention;

[0025] Figure 8 It is a three-dimensional structural cross-sectional view of the first fixed shell and the second fixed shell of the present invention.

[0026] Figure numbers: 1: main body, 101: sliding groove, 2: sliding ring, 3: rotating shaft, 4: threaded cylinder, 5: motor, 6: first baffle, 7: second baffle, 8: rotating shell, 9: rotating ring, 10: contact block, 11: first fixed shell, 12: first sliding rod, 13: contact piece, 14: locking piece, 15: fixed rod, 16: second fixed shell, 17: second sliding rod, 18: limit piece, 19: annular shell. DETAILED DESCRIPTION

[0027] Reference to an embodiment herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] When using the existing thread plug gauge, the thread plug gauge and the thread of the drill rod joint to be tested are often not in a straight line. In this case, screwing the thread plug gauge into the thread of the drill rod joint to be tested will cause the thread plug gauge to wear more severely, resulting in reduced accuracy or even damage to the thread plug gauge.

[0029] Embodiment 1: A thread measuring device for detecting a petroleum drill pipe joint, such as Figure 1-Figure 8As shown, it includes a main body 1, a sliding ring 2 is slidably connected to the right side of the main body 1, and a rotating shaft 3 is rotatably connected to the inner side of the sliding ring 2 through a mounting frame, a threaded barrel 4 is fixedly connected to the left side of the rotating shaft 3, and three T-shaped support frames evenly distributed in the circumferential direction are fixedly connected to the main body 1, and the support frames are slidably matched with the threaded barrel 4. The support frames are used to provide support for the threaded barrel 4 to prevent the threaded barrel 4 from tilting under the action of gravity, and the length of the support frame along the axial direction of the threaded barrel 4 is greater than the pitch of the threaded barrel 4, which is used to make the threaded barrel 4 move stably and prevent the support frame from being alternately located at the crest and valley of the thread causing the threaded barrel 4 to shake, the sliding ring 2 is fixedly connected to a motor 5 through the mounting frame, and the output shaft of the motor 5 is fixedly connected to two first baffles 6 symmetrically distributed front and back, and the output shaft of the motor 5 is slidably connected to two second baffles 7 symmetrically distributed up and down, and the second baffle 7 is squeezed and matched with the adjacent first baffle 6, and the first baffle 6 pushes the second baffle when it rotates to contact the adjacent second baffle 7 7 rotates, the two second baffles 7 are fixedly connected with a rotating shell 8, and the rotating shell 8 and the rotating shaft 3 are driven by a gear set. The main body 1 is rotatably connected with a rotating ring 9, and the rotating ring 9 is located in the wall of the main body 1. A contact block 10 is fixedly connected to the front side of the rotating ring 9. The contact block 10 is slidably connected with the main body 1 and penetrates it. A first fixed shell 11 is fixedly connected to the outer side of the main body 1, and a first sliding rod 12 is slidably connected to the upper side of the first fixed shell 11. A contact piece 13 is fixedly connected to the upper side of the first sliding rod 12. The contact piece 13 is a hollow triangular prism, and the contact piece 13 is pressed and matched with the contact block 10. When the contact block 10 rotates with the rotating ring 9, it contacts and presses the contact piece 13, causing the contact piece 13 to deform. Among the wires that form a loop with the motor 5, one is divided into two sections, one section is connected to the contact block 10, and the other section is connected to the contact piece 13. The contact piece 13 is made of elastic metal material, which is used to make it stably connected with the contact block 10.

[0030] like Figure 2 , Figure 3 and Figure 7 As shown, the main body 1 is slidably connected with three L-shaped locking members 14 which are evenly distributed in the circumference. The locking members 14 penetrate the inner side of the main body 1. Springs are arranged between the right sides of the three locking members 14 and the main body 1, and the springs are used to reset the adjacent locking members 14. The inner side of the rotating ring 9 is provided with three limiting grooves which are evenly distributed in the circumference. The locking members 14 are limitedly matched with the adjacent limiting grooves on the rotating ring 9. When the locking members 14 are in contact with the adjacent limiting grooves on the rotating ring 9, the rotating ring 9 cannot rotate. The locking members 14 are provided with an unlocking groove for allowing the rotating ring 9 to pass.

[0031] like Figure 2 As shown, the main body 1 is provided with three sliding grooves 101 evenly distributed in the circumference, and a fixing rod 15 is slidably connected in the sliding groove 101. The fixing rod 15 penetrates the inner side of the main body 1. The fixing rod 15 is used to fix the main body 1, so as to prevent shaking during the operation of the device to affect the measurement.

[0032] like Figure 2 , Figure 6 and Figure 8 As shown, the main body 1 is fixed with three second fixed shells 16 evenly distributed in the circumference through a fixed block, the second fixed shells 16 are slidably connected with second sliding rods 17, the three second sliding rods 17 are all fixed with the rotating ring 9 through the fixed block, and a spring is arranged between the second sliding rod 17 and the second fixed shell 16. The spring is initially in a compressed state and is used to drive the rotating ring 9 to rotate by pushing adjacent second sliding rods 17.

[0033] like Figure 2 , Figure 6 and Figure 8 As shown, the fixed rod 15 is composed of a round rod and a disc, the disc is slidably connected to the sliding groove 101, the round rod passes through the main body 1, and a fixing buckle is fixedly connected to one side of the round rod located in the main body 1, which is used to increase the stability of the three fixed rods 15 when clamping the drill pipe joint. The sliding groove 101 is located on the side of the disc close to the round rod and is filled with liquid. The liquid mentioned here and below is hydraulic oil for transmission. Liquid is filled between the second sliding rod 17 and the second fixed shell 16. The second fixed shell 16 is connected to the adjacent sliding groove 101 through a hose, and the hose is located in the wall of the main body 1.

[0034] like Figure 1 and Figure 6 As shown, the outer side of the main body 1 is slidably connected to the limiting member 18 through the mounting plate. The limiting member 18 is composed of a round rod and a wedge-shaped block. A spring is arranged between the right side of the mounting plate and the limiting member 18. The spring is used to reset the limiting member 18. The contact block 10 is provided with a limiting groove that cooperates with the limiting member 18. When the wedge-shaped block of the limiting member 18 is inserted into the limiting groove of the contact block 10, the contact block 10 cannot move.

[0035] When using the device, first connect the power supply of the motor 5. At this time, because there is no contact between the contact block 10 and the contact piece 13, the motor 5 will not work temporarily. Then, the left side of the device is put on the thread of the oil drill pipe joint to be measured, and then the device is continued to be moved. At this time, the locking piece 14 contacts the drill pipe joint and stops moving. The main body 1 continues to move to the left and compresses the spring between it and the locking piece 14. When the unlocking grooves of the three locking pieces 14 are aligned with the rotating ring 9, the second sliding rod 17 drives the rotating ring 9 to rotate under the action of the adjacent spring. At this time, the thread of the drill pipe joint contacts the thread of the threaded barrel 4, and the rotating ring 9 drives the contact block 10 to rotate. The contact block 10 rotates until it contacts the contact piece 13 and squeezes the contact piece 13 to deform, so as to avoid the contact between the contact block 10 and the contact piece 13. Good, when the contact block 10 contacts with the contact piece 13, the contact block 10 squeezes the limit piece 18 to move to the left and compresses the adjacent spring. When the limit piece 18 is aligned with the limit groove on the contact block 10, the limit piece 18 is inserted into the limit groove on the contact block 10 under the action of the adjacent spring, thereby locking the contact block 10 to prevent the contact block 10 from separating from the contact piece 13. When the contact block 10 contacts with the contact piece 13, the motor 5 starts to work, and the output shaft of the motor 5 drives the two first baffles 6 to rotate. The first baffle 6 squeezes the adjacent second baffle 7, and the second baffle 7 drives the rotating shell 8 to rotate. The rotating shell 8 drives the rotating shaft 3 to rotate through the gear set, and the rotating shaft 3 drives the threaded barrel 4 to rotate. The threaded barrel 4 is screwed into the thread of the drill pipe joint, and the threaded barrel 4 drives the sliding ring 2 to slide to the left through the rotating shaft 3.

[0036] When the second sliding rod 17 moves, the second sliding rod 17 moves outward from the adjacent second fixed shell 16, and the space in the second fixed shell 16 increases to form a negative pressure, so that the liquid in the adjacent sliding groove 101 is sucked into the second fixed shell 16 through the hose, and the liquid in the sliding groove 101 is reduced to form a negative pressure, which drives the adjacent fixed rod 15 to move toward the direction close to the axis of the main body 1, so that the three fixed rods 15 clamp the drill pipe joint to prevent the device from shaking during the measurement process.

[0037] When the measurement is completed, the motor 5 rotates in the opposite direction, so that the transmission threaded barrel 4 withdraws from the thread of the drill pipe joint. When the threaded barrel 4 is separated from the thread of the drill pipe joint, the motor 5 is turned off, and then the limiter 18 is pulled to the left, so that the limiter 18 releases the limit on the contact block 10 and compresses the adjacent spring, and then the contact block 10 is reset, and the contact block 10 drives the rotating ring 9 to rotate, and the rotating ring 9 drives the three second sliding rods 17 to rotate, and the second sliding rods 17 are reset and compress the adjacent springs. When the second sliding rod 17 is reset, the liquid in the adjacent second fixed shell 16 is pressed into the adjacent sliding groove 101 through the hose, and the liquid in the sliding groove 101 increases, pushing the adjacent fixed rod 15 to reset, so that the fixed rod 15 releases the clamping of the drill pipe joint, and when the contact block 10 returns to its original position, the limiter groove of the rotating ring 9 is aligned with the adjacent locking member 14, and the locking member 14 is reset under the action of the adjacent spring, and the rotating ring 9 is locked again. At this time, the device can be removed from the drill pipe joint and prepared for the next measurement.

[0038] When the thread plug gauge encounters a hard protrusion on the thread of the drill pipe joint to be tested during the process of screwing in the thread plug gauge, continuing to screw in the thread plug gauge may cause damage to the thread plug gauge.

[0039] Embodiment 2: Based on embodiment 1, Figure 2-Figure 5 and Figure 8 As shown, it also includes an annular shell 19, which is fixed to the left side of the sliding ring 2 through a mounting frame. The annular shell 19 is rotatably connected to the rotating shell 8. The rotating shell 8 is provided with two symmetrically distributed through holes, which are used to connect the annular shell 19 with the inner side of the rotating shell 8. The two first baffles 6, the two second baffles 7, the rotating shell 8 and the output shaft of the motor 5 together form four evenly distributed cavities, and the cavities adjacent to the through holes on the rotating shell 8 are filled with liquid. The first fixed shell 11 and the first sliding rod 12 are filled with liquid and are provided with a tension spring, which is used to reset the first sliding rod 12. The annular shell 19 is connected to the first fixed shell 11 through a hose.

[0040] When the motor 5 is working, if there is a solid protrusion on the thread of the drill pipe joint, the threaded barrel 4 is blocked during the screwing process, so that the threaded barrel 4 cannot rotate, and the threaded barrel 4 drives the two second baffles 7 to stop rotating. At this time, the output shaft of the motor 5 still drives the two first baffles 6 to rotate. The first baffle 6 squeezes the liquid in the adjacent cavity into the annular shell 19 through the through hole on the rotating shell 8, and then the liquid enters the first fixed shell 11 through the hose. The liquid in the first fixed shell 11 increases, pushing the first sliding rod 12 to move to the outside of the first fixed shell 11 and pulling the adjacent tension spring. The first sliding rod 12 drives the contact piece 13 to move, and the contact piece 13 moves to separate from the contact block 10, so that the motor 5 is powered off. At this time, the motor 5 stops working and the threaded barrel 4 stops rotating, thereby preventing the threaded barrel 4 from being damaged. When the motor 5 stops working, the rotation direction of the motor 5 is adjusted to reverse the motor 5. At this time, the first sliding rod 12 is slowly reset under the action of the adjacent tension spring and re-contacts with the contact piece 13. After the motor 5 is powered on, it reverses to withdraw the threaded barrel 4 from the thread of the drill pipe.

[0041] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A thread measuring device for detecting oil drill pipe joints, characterized in that: The invention comprises a main body (1), wherein a sliding ring (2) is slidably connected to one side of the main body (1), wherein the sliding ring (2) is rotatably connected to a rotating shaft (3) via a first mounting frame, wherein the rotating shaft (3) is fixedly connected to a threaded cylinder (4), wherein the sliding ring (2) is fixedly connected to a motor (5) via a second mounting frame, wherein the output shaft of the motor (5) is fixedly connected to a symmetrically distributed first baffle (6), wherein the output shaft of the motor (5) is slidably connected to a symmetrically distributed second baffle (7), wherein the second baffle (7) is extruded and matched with the adjacent first baffle (6), wherein the symmetrically distributed second baffles (7) are jointly fixedly connected to a rotating shell (8), wherein the rotating shell (8) and the rotating shaft (3) are driven by a gear set, wherein the main body (1) ) is rotatably connected to a rotating ring (9), the rotating ring (9) is fixedly connected to a contact block (10), the contact block (10) is slidably connected to the main body (1) and penetrates the main body (1), the outer side of the main body (1) is fixedly connected to a first fixed shell (11), the side of the first fixed shell (11) close to the contact block (10) is slidably connected to a first sliding rod (12), the side of the first sliding rod (12) away from the first fixed shell (11) is fixedly connected to a contact piece (13), the contact piece (13) is pressed and fitted with the contact block (10), and one of the wires forming a loop with the motor (5) is divided into two sections, one section is connected to the contact block (10), and the other section is connected to the contact piece (13).

2. A thread measuring device for detecting a petroleum drill pipe joint according to claim 1, characterized in that: The contact piece (13) is made of elastic metal material and is used to ensure a stable connection between it and the contact block (10).

3. A thread measuring device for detecting a petroleum drill pipe joint according to claim 1, characterized in that: A support frame evenly distributed in the circumferential direction is fixedly connected to the main body (1), and the support frame is in sliding cooperation with the threaded cylinder (4).

4. A thread measuring device for detecting a petroleum drill pipe joint according to claim 3, characterized in that: The length of the support frame along the axial direction of the threaded barrel (4) is greater than the pitch of the threaded barrel (4), and is used to enable the threaded barrel (4) to move stably.

5. A thread measuring device for detecting a petroleum drill pipe joint according to claim 1, characterized in that: The main body (1) is slidably connected with locking members (14) which are evenly distributed in the circumferential direction. The locking members (14) penetrate the inner side of the main body (1). Springs are arranged between the locking members (14) which are evenly distributed in the circumferential direction and the main body (1). The rotating ring (9) is provided with limiting grooves which are evenly distributed in the circumferential direction. The locking members (14) are limitedly matched with adjacent limiting grooves on the rotating ring (9). The locking members (14) are provided with unlocking grooves for allowing the rotating ring (9) to pass.

6. A thread measuring device for detecting a petroleum drill pipe joint according to claim 1, characterized in that: The main body (1) is provided with sliding grooves (101) evenly distributed in the circumferential direction, a fixing rod (15) is slidably connected in the sliding groove (101), the fixing rod (15) penetrates the inner side of the main body (1), and the fixing rod (15) is used to fix the main body (1).

7. A thread measuring device for detecting a petroleum drill pipe joint according to claim 6, characterized in that: The main body (1) is fixedly connected to a second fixed shell (16) evenly distributed in the circumference, the second fixed shell (16) is slidably connected to a second sliding rod (17), the second sliding rods (17) evenly distributed in the circumference are all fixedly connected to the rotating ring (9), and a spring is provided between the second sliding rod (17) and the second fixed shell (16).

8. A thread measuring device for detecting a petroleum drill pipe joint according to claim 7, characterized in that: The fixed rod (15) is composed of a round rod and a round disc, the round disc is slidably connected to the sliding groove (101), the round rod penetrates the main body (1), the sliding groove (101) is located on a side of the round disc close to the round rod and is filled with liquid, the second sliding rod (17) and the second fixed shell (16) are filled with liquid, the second fixed shell (16) and the adjacent sliding groove (101) are connected via a first hose, and the first hose is located in the wall of the main body (1).

9. A thread measuring device for detecting a petroleum drill pipe joint according to claim 1, characterized in that: The outer side of the main body (1) is slidably connected to a limiting member (18) via a mounting plate, a spring is provided between a side of the mounting plate close to the contact block (10) and the limiting member (18), and the contact block (10) is provided with a limiting groove that cooperates with the limiting member (18) for limiting.

10. A thread measuring device for detecting a petroleum drill pipe joint according to claim 1, characterized in that: The invention also comprises an annular shell (19), wherein the annular shell (19) is fixedly connected to a side of the sliding ring (2) close to the rotating shell (8), the annular shell (19) is rotatably connected to the rotating shell (8), the rotating shell (8) is provided with symmetrically distributed through holes, the symmetrically distributed first baffles (6), the symmetrically distributed second baffles (7), the rotating shell (8) and the output shaft of the motor (5) together form uniformly distributed cavities, the cavities adjacent to the through holes on the rotating shell (8) are filled with liquid, the first fixed shell (11) and the first sliding rod (12) are filled with liquid and are provided with a tension spring, and the annular shell (19) is connected to the first fixed shell (11) through a second hose.

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