A logging probe shell pressure detection device

Abstract

This invention belongs to the field of engineering exploration technology, specifically a well logging probe shell pressure detection device, including a well logging probe body for detecting relevant data in the well; a shell, which is integrally formed from an outer shell and an inner shell, with a partition fixed to the top of the shell, a connecting cover fixed to the top of the partition, and an installation pipe for connecting to an external driving device fixed to the top of the connecting cover; and an ultrasonic detection component, including a movable stage movably fitted in the gap between the outer shell and the inner shell, with an ultrasonic generator installed on the side wall of the movable stage. This invention uses the ultrasonic detection component to detect reflected waves from the shell wall to assess the stress condition. Furthermore, a driving component moves the ultrasonic detection component up and down, increasing its detection range and improving the detection effect, allowing for continuous monitoring of the device's stress condition in the well.

Description

Technical Field

[0001] This invention belongs to the field of engineering exploration technology, specifically a pressure detection device for the outer shell of a well logging probe. Background Technology

[0002] Downhole magnetic logging is a geophysical method that detects targets by measuring the strength and susceptibility of the magnetic field in the well. In existing logging techniques, when the downhole instrument encounters an obstruction, operators are generally prohibited from using the downhole probe to impact the obstruction. Furthermore, when the hoisting cable becomes stuck, the operation should be stopped immediately, and attempts should be made to free it by moving the cable up and down. If this fails, the operator must quickly designate a specific person and consult with the drilling team to find a solution to prevent further complications.

[0003] Currently, the pressure on the outer wall of the instrument cannot be monitored in real time during operation, making it difficult for operators to understand the actual situation downhole in the event of a stuck well. This lack of information makes rapid consultation and resolution more difficult, increasing the complexity of accident handling.

[0004] Therefore, the present invention provides a well logging probe housing pressure detection device. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0006] The technical solution adopted by this invention to solve its technical problem is: a well logging probe housing pressure detection device according to this invention, comprising:

[0007] The logging probe body is used to detect relevant data in the well;

[0008] The housing is integrally formed from an outer shell and an inner shell. The bottom of the housing is closed and the top of the housing is open. The main body of the logging probe is installed in the middle of the inner shell. A partition is fixed to the top of the housing to seal the gap between the outer shell and the inner shell. A connecting cover is fixed to the top of the partition, and an installation pipe for connecting to an external drive device is fixed to the top of the connecting cover.

[0009] An ultrasonic testing assembly includes a movable stage, which is movably fitted in the gap between an outer shell and an inner shell, and an ultrasonic generator is installed on the side wall of the movable stage.

[0010] The drive assembly drives the moving stage and ultrasonic generator to move up and down, thereby allowing for continuous monitoring of the forces acting on the outer shell within the well.

[0011] Preferably, the drive assembly includes a lead screw, which is disposed below the partition. The lead screw vertically passes through a threaded hole in the middle of the moving platform and is threadedly connected thereto. A gear disk is rotatably mounted in the middle of the connecting cover. A motor for driving the gear disk to rotate is fixedly mounted on the top of the connecting cover. A helical gear one is meshed with the side of the gear disk. A helical gear two is fixed to one side of the helical gear through a connecting rod. A helical gear three is meshed with the lower part of the helical gear two. A rotating rod is fixedly connected in the middle of the helical gear three. The bottom end of the rotating rod passes through the partition and is fixedly connected to the lead screw. The rotating rod is rotatably connected to the partition.

[0012] Preferably, a coupling agent application assembly is provided below the moving platform. The coupling agent application assembly includes a mounting plate with nozzles on its side wall, each nozzle corresponding to an ultrasonic generator. The lead screw is hollow in the middle, and a spiral conveying shaft is fixedly installed inside the lead screw. A sleeve is fixed on the lower end face of the partition and directly above the lead screw. The sleeve is movably fitted onto the top of the lead screw, and there is a gap between the top of the lead screw and the partition. A connecting hose is fixed on the side wall of the sleeve, and the end of the connecting hose away from the sleeve is fixedly connected to the moving platform. The moving platform and the mounting plate have cavities for temporarily storing coupling agent, and the cavities are respectively connected to the connecting hose and the nozzles.

[0013] Preferably, the connecting hose is a spiral hose.

[0014] Preferably, a fixed plate is fixedly connected to the inner cavity of the lead screw and located above the screw conveyor shaft. The bottom end of the rotating rod is fixedly connected to the middle of the top of the fixed plate. The fixed plate has symmetrical through holes, and a flap is rotatably installed on the top of the through holes by a torsion spring.

[0015] Preferably, a controller is fixedly installed on the top of the connecting cover, and the controller is electrically connected to the ultrasonic detection component and the external terminal equipment respectively.

[0016] Preferably, a limiting plate is fixedly connected to the opposite sidewalls of the outer shell and the inner shell, and a limiting groove adapted to the limiting plate is provided on the moving platform, and the limiting plate is slidably disposed in the limiting groove.

[0017] Preferably, the ultrasonic generator is slidably mounted in a mounting hole on the side wall of the moving stage, and a spring is installed inside the moving stage to reset the ultrasonic generator.

[0018] Preferably, the partition is fixedly installed on the top of the outer shell and the inner shell by bolts, and the connecting cover is fixedly installed on the top of the partition by bolts.

[0019] Preferably, an agitation assembly is provided at the bottom of the gap between the outer shell and the inner shell. The agitation assembly includes a first movable ring and a second movable ring. The first movable ring and the second movable ring are concentric rings. The first movable ring and the second movable ring are fixedly connected by a connecting block. A universal wheel is fixedly installed at the bottom of the connecting block. An internal toothed ring is fixed to the inner wall of the first movable ring, and an external toothed ring is fixed to the outer wall at the bottom of the lead screw. The external toothed ring meshes with the internal toothed ring.

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

[0021] 1. The well logging probe housing pressure detection device of the present invention, by setting up a driving component and an ultrasonic detection component, emits ultrasonic waves to the housing through an ultrasonic generator during use, and detects the reflected waves of the housing wall to assess the stress condition. In addition, the driving component drives the moving stage and ultrasonic generator to move up and down, so that the detection range of the ultrasonic detection component is wider and the detection effect is improved. This allows for real-time observation of the stress condition of the device in the well, avoiding well jamming, and facilitating the detection of the probe stress condition after a well jamming accident.

[0022] 2. The well logging probe housing pressure detection device of the present invention facilitates the spraying of coupling agent onto the inner wall of the housing by setting a coupling agent application component. During use, the lead screw synchronously drives the internal spiral conveying shaft to rotate. The spiral conveying shaft pushes the coupling agent located at the bottom of the gap upward along the inner cavity of the lead screw. The casing rotates and is fitted onto the top of the lead screw without affecting the rotation of the lead screw, and the coupling agent can enter the casing, then enter the cavity inside the moving platform and the mounting plate through the connecting hose, and finally be sprayed onto the inner wall of the housing from the nozzle. Afterward, when the moving platform drives the ultrasonic generator downward, the ultrasonic generator can contact the coupling liquid on the inner wall of the housing. This fills the gap in the sound wave propagation path, enhances the signal strength, and improves the detection sensitivity of the ultrasonic detection component. In addition, the coupling agent will slide down along the inner wall of the housing under the action of gravity and collect again at the bottom of the gap between the outer and inner shells. This allows for the recycling and reuse of the coupling agent, improves the utilization rate of the coupling agent, and saves costs. Attached Figure Description

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] Figure 1 This is a perspective view of the present invention;

[0025] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0026] Figure 3 This is a cross-sectional view of the present invention;

[0027] Figure 4 yes Figure 3Enlarged view of a portion of point A in the middle;

[0028] Figure 5 This is a top view of the mobile platform of the present invention;

[0029] Figure 6 This is a schematic diagram of the stirring component structure of the present invention.

[0030] In the diagram: 1. Shell; 11. Outer shell; 12. Inner shell; 2. Connecting cover; 21. Partition plate; 3. Mounting pipe; 4. Ultrasonic detection assembly; 41. Moving stage; 42. Ultrasonic generator; 43. Spring; 5. Drive assembly; 51. Motor; 52. Gear disc; 53. Helical gear one; 54. Connecting rod; 55. Helical gear two; 56. Helical gear three; 57. Rotating rod; 58. Lead screw; 6. Coupling agent application assembly; 61. Mounting plate; 62. Nozzle; 63. Spiral conveyor shaft; 64. Fixed plate; 65. Flip plate; 66. Casing; 67. Connecting hose; 7. Logging probe body; 8. Limiting plate; 9. Agitation assembly; 91. Movable ring one; 92. Movable ring two; 93. Connecting block; 94. Caster wheel; 95. Internal gear ring; 96. External gear ring; 10. Controller. Detailed Implementation

[0031] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0032] Example 1: As Figures 1 to 5 As shown in the figure, a well logging probe housing pressure detection device according to an embodiment of the present invention includes:

[0033] The logging probe body 7 is used to detect relevant data in the well;

[0034] The housing 1 is integrally formed from an outer shell 11 and an inner shell 12. The housing 1 is made of a material that does not interfere with magnetic fields, such as non-magnetic stainless steel. The bottom of the housing 1 is closed and the top of the housing 1 is open. The logging probe body 7 is installed in the middle of the inner shell 12. A partition 21 is fixed to the top of the housing 1 to seal the top of the gap between the outer shell 11 and the inner shell 12. A connecting cover 2 is fixed to the top of the partition 21, and an installation pipe 3 for connecting to an external drive device is fixed to the top of the connecting cover 2.

[0035] The ultrasonic testing component 4 includes a movable stage 41, which is movably fitted in the gap between the outer shell 11 and the inner shell 12. An ultrasonic generator 42 is installed on the side wall of the movable stage 41.

[0036] The drive assembly 5 drives the moving stage 41 and the ultrasonic generator 42 to move up and down, thereby constantly observing the stress on the outer shell 11 in the well.

[0037] During operation, the device is installed on an external drive device via the installation pipe 3 and lowered into the well. Then, the logging probe body 7 is used to detect relevant data in the well. During the movement of the device, ultrasonic generator 42 emits ultrasonic waves to the outer shell 11 and detects the reflected waves on the wall of the outer shell 11 to assess the stress. In addition, the drive assembly 5 drives the moving platform 41 and ultrasonic generator 42 to move up and down, which makes the detection range of the ultrasonic detection assembly 4 wider and improves the detection effect. This allows for real-time observation of the stress on the device in the well, avoiding well jamming and facilitating real-time detection of the stress on the probe after a well jamming accident.

[0038] The drive assembly 5 includes a lead screw 58, which is located below the partition 21. The lead screw 58 vertically passes through the threaded hole in the middle of the moving platform 41 and is threadedly connected to it. A gear disk 52 is rotatably mounted in the middle of the connecting cover 2. A motor 51 for driving the gear disk 52 to rotate is fixedly mounted on the top of the connecting cover 2. A helical gear 1 53 is meshed with the side of the gear disk 52. A helical gear 2 55 is fixed to the side of the helical gear 1 53 through a connecting rod 54. A helical gear 3 56 is meshed with the lower part of the helical gear 2 55. A rotating rod 57 is fixedly connected in the middle of the helical gear 3 56. The bottom end of the rotating rod 57 passes through the partition 21 and is fixedly connected to the lead screw 58. The rotating rod 57 is rotatably connected to the partition 21.

[0039] When in operation, the motor 51 is started, which drives the gear disc 52, helical gear 1 53, helical gear 2 55 and helical gear 3 56 to rotate. In turn, the rotating rod 57 drives the lead screw 58 to rotate. The moving table 41 is threadedly connected to the lead screw 58, which in turn drives the moving table 41 and the ultrasonic generator 42 to move up and down reciprocally. This allows the ultrasonic generator 42 to emit ultrasonic waves to different positions on the outer shell 11, thus enabling the detection of the stress on the outer shell 11 and expanding the detection range.

[0040] A coupling agent application assembly 6 is provided below the moving platform 41. The coupling agent application assembly 6 includes a mounting plate 61. A nozzle 62 is provided on the side wall of the mounting plate 61. The nozzle 62 corresponds one-to-one with the ultrasonic generator 42. The lead screw 58 is hollow in the middle, and a spiral conveying shaft 63 is fixedly installed inside the lead screw 58. A sleeve 66 is fixed on the lower end face of the partition plate 21 and located directly above the lead screw 58. The sleeve 66 is movably sleeved on the top of the lead screw 58. There is a gap between the top of the lead screw 58 and the partition plate 21. A connecting hose 67 is fixed on the side wall of the sleeve 66. The end of the connecting hose 67 away from the sleeve 66 is fixedly connected to the moving platform 41. The moving platform 41 and the mounting plate 61 have cavities for temporarily storing coupling agent, and the cavities are respectively connected to the connecting hose 67 and the nozzle 62.

[0041] During operation, a coupling agent is pre-stored in the gap between the outer shell 11 and the inner shell 12. When the moving stage 41 is driven downward by the lead screw 58, the lead screw 58 synchronously drives the internal spiral conveyor shaft 63 to rotate. The spiral conveyor shaft 63 pushes the coupling agent located at the bottom of the gap upward along the inner cavity of the lead screw 58. The sleeve 66 rotates and is fitted onto the top of the lead screw 58 without affecting the rotation of the lead screw 58. The coupling agent can then enter the cavity inside the moving stage 41 and the mounting plate 61 through the connecting hose 67, and finally be sprayed from the nozzle 62 onto the inner wall of the outer shell 11. Afterward, when the moving stage 41 drives the ultrasonic generator 42 to move downward, The ultrasonic generator 42 can contact the coupling fluid on the inner wall of the housing 11, thereby filling the gaps in the sound wave propagation path, enhancing the signal strength, and improving the detection sensitivity of the ultrasonic detection component 4. In addition, the coupling agent will slide down the inner wall of the housing 11 under the action of gravity and re-collect at the bottom of the gap between the housing 11 and the inner housing 12. This allows for the recycling and reuse of the coupling agent, improving its utilization rate and saving costs. Furthermore, an injection hole can be provided at the bottom of the housing 1. When detection is required, the coupling agent can be injected into the gap through the injection hole for convenient use during the detection process. In addition, the coupling agent can be extracted for easy replacement.

[0042] The connecting hose 67 is a spiral hose; during operation, the connecting hose 67 can extend and retract with the up and down movement of the moving platform 41 without interfering with the movement of the moving platform 41.

[0043] A fixed disk 64 is fixedly connected to the inner cavity of the lead screw 58 and above the screw conveyor shaft 63. The bottom end of the rotating rod 57 is fixedly connected to the top center of the fixed disk 64. The fixed disk 64 has symmetrical through holes, and a flap 65 is rotatably installed on the top of the through holes via a torsion spring. During operation, the fixed disk 64 fixes the rotating rod 57 and the lead screw 58 together to achieve power transmission. By setting the flap 65, when the lead screw 58 pushes the moving platform 41 downward, the coupling agent is pushed upward by the screw conveyor shaft 63, and the coupling agent pushes the flap 65 to flip upward and open. When the lead screw 58 rotates in the opposite direction and drives the moving platform 41 upward, the screw conveyor shaft 63 moves in the opposite direction, and the coupling agent is no longer pushed upward. Under the rebound of the torsion spring, the flap 65 is reset, resealing the through hole and preventing the coupling agent inside the lead screw 58 from flowing downward, so that when the moving platform 41 moves downward again, the coupling agent can be sprayed out from the nozzle 62 in time.

[0044] A controller 10 is fixedly installed on the top of the connecting cover 2. The controller 10 is electrically connected to the ultrasonic detection component 4 and the external terminal equipment. During operation, the controller 10 is equipped with an ultrasonic processing unit that can receive reflected ultrasonic waves to assess the stress on the outer shell 11 based on the reflected waves. When an abnormal stress is detected, the stress location can be recorded and the detection results can be sent to the external terminal equipment so that the operator can understand the stress on the outer shell 11 in a timely manner and reduce the probability of well jamming. In addition, it also avoids damage to the device due to operational errors.

[0045] Limiting plates 8 are fixedly connected to the opposite side walls of the outer shell 11 and the inner shell 12. The moving stage 41 is provided with a limiting groove that is adapted to the limiting plate 8. The limiting plate 8 is slidably disposed in the limiting groove. During operation, by setting the limiting plate 8 and the limiting groove, the movement direction of the moving stage 41 is restricted, so that the moving stage 41 can only move up and down along the gap between the outer shell 11 and the inner shell 12.

[0046] The ultrasonic generator 42 is slidably mounted in a mounting hole on the side wall of the moving stage 41. A spring 43 is installed inside the moving stage 41 to reset the ultrasonic generator 42. During operation, when the outer shell 11 is deformed by external force, the ultrasonic generator 42 corresponding to the deformation position can retract into the mounting hole so that the moving stage 41 can pass through the deformation position smoothly and continue to detect other positions.

[0047] The partition 21 is fixedly installed on the top of the outer shell 11 and the inner shell 12 by bolts, and the connecting cover 2 is fixedly installed on the top of the partition 21 by bolts. During operation, the partition 21 and the connecting cover 2 are fixedly installed by bolts so as to quickly install and remove the partition 21 and the connecting cover 2, and facilitate the maintenance of the internal parts of the device.

[0048] Example 2: Figure 3 and Figure 6 As shown in the comparative embodiment one, another embodiment of the present invention is as follows: an agitation component 9 is provided at the bottom of the gap between the outer shell 11 and the inner shell 12. The agitation component 9 includes a first movable ring 91 and a second movable ring 92. The first movable ring 91 and the second movable ring 92 are concentric rings and are fixedly connected by a connecting block 93. A universal wheel 94 is fixedly installed at the bottom of the connecting block 93. An internal toothed ring 95 is fixed to the inner wall of the first movable ring 91, and an external toothed ring 96 is fixed to the outer wall of the bottom of the lead screw 58. The external toothed ring 96 meshes with the internal toothed ring 95. During operation, the universal wheel 94 supports the first movable ring 91 and the second movable ring 92. When the lead screw 58 rotates, the external toothed ring 96 at the bottom pushes the internal toothed ring 95 to move, thereby driving the first movable ring 91 and the second movable ring 92 to rotate. This can agitate the coupling agent at the bottom of the gap, preventing some coupling agent from settling when stationary, which would affect the viscosity of the coupling agent and thus its dispersibility.

[0049] Working principle: The device is lowered into the well to detect relevant data. Simultaneously, the ultrasonic generator 42 emits ultrasonic waves into the outer casing 11, detecting the reflected waves from the casing 11 wall to assess the stress. Furthermore, the motor 51 drives the lead screw 58 to rotate, which in turn moves the moving stage 41 and the ultrasonic generator 42 up and down, thus widening the detection range of the ultrasonic detection component 4 and improving the detection effect. This allows for continuous monitoring of the stress on the device in the well, preventing well jamming or ensuring timely detection of the probe's stress during accident handling. The rotation of the lead screw 58 also drives the internal spiral conveyor shaft 63 to rotate, transporting materials via the spiral conveyor... Shaft 63 pushes the coupling agent located at the bottom of the gap upward along the inner cavity of the lead screw 58. The sleeve 66 is rotated and fitted on the top of the lead screw 58 without affecting the rotation of the lead screw 58. The coupling agent can enter the sleeve 66, and then enter the cavity inside the moving stage 41 and the mounting plate 61 through the connecting hose 67. Finally, it is sprayed from the nozzle 62 onto the inner wall of the housing 11. Afterward, when the moving stage 41 drives the ultrasonic generator 42 to move downward, the ultrasonic generator 42 can contact the coupling liquid on the inner wall of the housing 11. In this way, by filling the gap in the sound wave propagation path, the signal strength is enhanced and the detection sensitivity of the ultrasonic detection component 4 is improved.

[0050] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0051] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A well logging probe housing pressure detection device, characterized in that: include: The logging probe body is used to detect relevant data in the well; The housing is integrally formed from an outer shell and an inner shell. The bottom of the housing is closed and the top of the housing is open. The main body of the logging probe is installed in the middle of the inner shell. A partition is fixed to the top of the housing to seal the gap between the outer shell and the inner shell. A connecting cover is fixed to the top of the partition, and an installation pipe for connecting to an external drive device is fixed to the top of the connecting cover. An ultrasonic testing assembly includes a movable stage, which is movably fitted in the gap between an outer shell and an inner shell, and an ultrasonic generator is installed on the side wall of the movable stage. The drive assembly drives the moving stage and ultrasonic generator to move up and down, thereby allowing for real-time monitoring of the stress on the outer shell in the well. The drive assembly includes a lead screw, which is located below the partition. The lead screw vertically passes through a threaded hole in the middle of the moving platform and is threadedly connected to it. A gear disk is rotatably mounted in the middle of the connecting cover. A motor for driving the gear disk to rotate is fixedly mounted on the top of the connecting cover. A helical gear one is meshed with the side of the gear disk. A helical gear two is fixed to one side of the helical gear through a connecting rod. A helical gear three is meshed with the bottom of the helical gear three. A rotating rod is fixedly connected in the middle of the helical gear three. The bottom end of the rotating rod passes through the partition and is fixedly connected to the lead screw. The rotating rod is rotatably connected to the partition. A coupling agent application assembly is provided below the moving platform. The coupling agent application assembly includes a mounting plate with nozzles on its side wall, each nozzle corresponding to an ultrasonic generator. The lead screw is hollow in the middle, and a spiral conveying shaft is fixedly installed inside the lead screw. A sleeve is fixed on the lower end face of the partition and directly above the lead screw. The sleeve is movably fitted onto the top of the lead screw, and there is a gap between the top of the lead screw and the partition. A connecting hose is fixed on the side wall of the sleeve, and the end of the connecting hose away from the sleeve is fixedly connected to the moving platform. The moving platform and the mounting plate have cavities for temporarily storing coupling agent, and these cavities are respectively connected to the connecting hose and the nozzles.

2. The well logging probe housing pressure detection device according to claim 1, characterized in that: The connecting hose is a spiral hose.

3. The well logging probe housing pressure detection device according to claim 2, characterized in that: A fixed plate is fixedly connected to the inner cavity of the lead screw and above the screw conveyor shaft. The bottom end of the rotating rod is fixedly connected to the middle of the top of the fixed plate. The fixed plate has symmetrical through holes, and a flap is rotatably installed on the top of the through holes by a torsion spring.

4. The well logging probe housing pressure detection device according to claim 3, characterized in that: A controller is fixedly installed on the top of the connecting cover, and the controller is electrically connected to the ultrasonic detection component and the external terminal equipment.

5. The well logging probe housing pressure detection device according to claim 4, characterized in that: Limiting plates are fixedly connected to the opposite side walls of the outer shell and the inner shell. A limiting groove adapted to the limiting plate is provided on the moving platform, and the limiting plate is slidably disposed in the limiting groove.

6. The well logging probe housing pressure detection device according to claim 5, characterized in that: The ultrasonic generator is slidably mounted in a mounting hole on the side wall of the moving stage, and a spring is installed inside the moving stage to reset the ultrasonic generator.

7. A well logging probe housing pressure detection device according to claim 6, characterized in that: The partition is fixedly installed on the top of the outer shell and the inner shell by bolts, and the connecting cover is fixedly installed on the top of the partition by bolts.

8. The well logging probe housing pressure detection device according to claim 7, characterized in that: A stirring assembly is provided at the bottom of the gap between the outer shell and the inner shell. The stirring assembly includes a first movable ring and a second movable ring. The first movable ring and the second movable ring are concentric rings. The first movable ring and the second movable ring are fixedly connected by a connecting block. A universal wheel is fixedly installed at the bottom of the connecting block. An internal toothed ring is fixed to the inner wall of the first movable ring, and an external toothed ring is fixed to the outer wall at the bottom of the lead screw. The external toothed ring meshes with the internal toothed ring.

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