Intelligent monitoring anti-loose oil extraction pressure cap

Abstract

The utility model discloses intelligent monitoring anti -loose oil exploitation pressure cap, it includes main cap body, axial limit ring, radial indicating rod, spiral guide groove seat and end face dial, is equipped with internal thread section in main cap body, is equipped with annular boss and axial limit ring to outer wall, spiral guide groove seat is set up in main cap body outside and is contacted with limit ring, its outer wall is equipped with spiral groove, one end of radial indicating rod roller is embedded in the groove, and the other end is connected with the pointer and points to end face dial, the application can convert the axial loose displacement of pressure cap into visual mechanical indication signal, and reserves remote sensing interface.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas extraction equipment technology, and in particular to intelligent monitoring and anti-loosening of oil extraction pressure caps. Background Technology

[0002] In oil extraction, wellhead connections are typically secured with pressure caps to ensure stability and reliable sealing at the tubing connection. Over long-term service, these pressure caps may loosen due to vibration, temperature variations, and alternating loads, leading to seal failure or reduced connection strength and posing safety hazards. To ensure operational safety, regular inspections or real-time monitoring of the pressure cap's tightness are necessary. Existing technologies integrate mechanical anti-loosening measures, such as lock nuts, retaining washers, or elastic retaining rings, which can delay loosening to some extent. However, these structures rely primarily on physical restraint or friction to maintain tightness, making it difficult to quantify the degree of loosening. Furthermore, their anti-loosening effectiveness is susceptible to changes in installation accuracy and environmental factors under complex operating conditions. In addition, traditional methods lack proactive sensing and remote feedback capabilities for pressure cap loosening, preventing maintenance personnel from promptly identifying potential risks and limiting the implementation of intelligent monitoring and preventative maintenance. Utility Model Content

[0003] The purpose of this utility model is to provide an intelligent monitoring and anti-loosening cap for oil extraction, which solves the problems mentioned in the background art.

[0004] This utility model is implemented as follows: an intelligent monitoring and anti-loosening oil extraction cap includes a main cap body, an axial limiting ring, a radial indicator rod, a spiral guide groove seat, and an end face scale, wherein:

[0005] The main cap is a cylindrical metal component with an internal thread section on its inner wall that matches the external thread of the wellhead tubing. A ring-shaped boss is arranged around the middle of its outer wall, and an annular groove is formed on the upper surface of the annular boss to accommodate an axial limiting ring. The axial limiting ring is an open elastic metal ring with an outer diameter slightly larger than the inner diameter of the annular groove. After assembly, it is embedded in the annular groove and maintains a pre-tightening pressure to limit the axial displacement of the main cap relative to the tubing. The top plane of the axial limiting ring has multiple positioning protrusions evenly distributed along the circumference. Each positioning protrusion has the same height and is used to contact the bottom of the spiral guide seat to form an initial reference position.

[0006] The spiral guide groove seat is an annular metal component, sleeved on the outer wall of the main cap and located above the annular boss. Its lower surface contacts the positioning protrusion of the axial limiting ring. Its inner wall has a guide surface that slides with the outer wall of the main cap. Its outer wall is machined with a continuous spiral groove. The pitch of the spiral groove is constant, and the direction of rotation is opposite to the direction of rotation of the internal thread of the main cap. The upper surface of the spiral guide groove seat has an annular step in the central area to support the end face scale of the receiving installation.

[0007] The radial indicator rod is a slender, rigid metal rod with a roller structure at one end. This roller structure is embedded in the spiral groove on the outer wall of the spiral guide seat and can roll along the groove trajectory. The other end extends to the outer space of the main cap body and is fixedly connected to the pointer head. The tip of the pointer head points to the scale line area on the end face dial. The middle part of the radial indicator rod passes through the fixed bracket, which is welded to the outer wall of the main cap body and has a through hole. The inner wall of the through hole is clearance-fitted with the outer wall of the radial indicator rod, allowing the radial indicator rod to translate as the spiral guide seat rotates.

[0008] The end face scale is a circular transparent plastic plate, the bottom of which is bonded to the upper surface of the annular step of the spiral guide groove seat. The top surface is printed with angle scale lines and displacement scale. The angle scale lines are distributed radially with the center as the reference, and the displacement scale is arranged along the circumference and corresponds to the pitch parameter of the spiral guide groove. A through hole is opened in the center of the end face scale. The diameter of the through hole is larger than the outer diameter of the main cap body to ensure that the spiral guide groove seat is not interfered with when it rotates.

[0009] Optionally, the top end face of the main cap body is provided with an annular sealing groove, in which an oil-resistant rubber sealing ring is embedded to form a sealing interface with the wellhead flange end face after the cap is tightened, preventing fluid in the well from leaking out along the thread gap.

[0010] Optionally, the outer wall of the spiral guide groove seat is also provided with a magnetic marking block. The magnetic marking block is fixed to the outer wall of the spiral guide groove seat and does not overlap with the spiral groove. Its position is aligned with the initial zero point of the radial indicator rod. The magnetic marking block is made of neodymium iron boron material and is covered with a stainless steel shell to prevent corrosion.

[0011] Optionally, the fixing bracket is an L-shaped metal plate, the vertical section of which is welded to the outer wall of the main cap, and the horizontal section is provided with a guide hole, the axis of which is perpendicular to the axis of the main cap; the inner wall of the guide hole is inlaid with a polytetrafluoroethylene bushing to reduce the frictional resistance when the radial indicator rod slides.

[0012] Optionally, the roller structure of the radial indicator rod consists of a miniature bearing and an outer nylon wheel. The inner ring of the miniature bearing is interference-fitted with the end of the radial indicator rod, and the outer ring of the nylon wheel contacts the side walls of the spiral groove to ensure smooth rolling without jamming.

[0013] Optionally, the edge of the end face dial is provided with a fluorescent coating, which covers the angle scale lines and the digital area of ​​the displacement scale, so that the reading can still be identified in low light conditions.

[0014] Optionally, the outer wall of the main cap body is provided with an annular groove near the bottom, and an anti-rotation baffle is engaged in the annular groove. One end of the anti-rotation baffle is inserted into the positioning hole of the wellhead base to limit the free rotation of the main cap body when it is not subjected to external force.

[0015] Optionally, the upper surface edge of the spiral guide groove seat is provided with an annular light-shielding eave. The annular light-shielding eave extends downward and covers the outer edge area of ​​the end face scale, which is used to block strong external light from shining directly on the scale surface and improve the clarity of reading.

[0016] Optionally, the end of the internal thread section of the main cap body is provided with a chamfered transition section with an angle of 30 degrees, which is used to guide the pipe thread to be screwed in smoothly and reduce the risk of thread damage during assembly.

[0017] Optionally, the opening of the axial limiting ring is provided with an overlapping tongue, and both ends of the overlapping tongue are provided with through holes. The overlapping tongue is locked by countersunk screws, so that the axial limiting ring forms a complete closed-loop structure after installation, thereby enhancing its axial constraint capability.

[0018] Optionally, the pointer head of the radial indicator is made of hollow aluminum alloy tubing, filled with lightweight foam material to reduce the overall weight and avoid indication deviation due to its own weight.

[0019] Optionally, the back of the end face dial is provided with calibration mark lines, which are aligned with the reference marks on the spiral guide seat to confirm the zero position accuracy during assembly.

[0020] Optionally, the outer wall of the main cap body is provided with a process screw hole, which penetrates the wall thickness of the main cap body and communicates with the bottom of the internal thread section, for injecting grease during the manufacturing process to reduce the friction coefficient of the thread pair.

[0021] Optionally, the bottom of the spiral guide seat is provided with an annular guide rail, which cooperates with the annular sliding groove on the outer wall of the main cap to ensure that the spiral guide seat can only rotate and not deflect radially when subjected to axial force.

[0022] Optionally, the top of the horizontal section of the fixed bracket is provided with a protective cover, which is a semi-cylindrical metal plate with both ends welded to the vertical section of the fixed bracket to cover the exposed part of the radial indicator rod and prevent external impact or foreign objects from getting entangled.

[0023] This utility model provides an intelligent monitoring and anti-loosening cap for oil extraction, which has the following beneficial effects:

[0024] This intelligent monitoring and anti-loosening oil extraction cap, through the cooperation of an axial limiting ring and a spiral guide groove seat, forces the spiral guide groove seat to rotate at a certain angle when the main cap body experiences slight axial displacement. This rotational motion is converted into a linear displacement of the pointer on the end face scale via a radial indicator rod, thus transforming the imperceptible loosening amount into a visually identifiable mechanical reading. The constant pitch design of the spiral guide groove ensures a precise mathematical relationship between the displacement and the rotation angle, allowing each reading to be converted into the actual axial movement distance. The introduction of a magnetic marker block provides a physical interface for future installation of a non-contact angle sensor, enabling electronic signal output without modifying the main structure. The combination of a fluorescent coating and a light-shielding visor improves reading reliability under extreme conditions, while the anti-rotation baffle and overlapping tongue enhance structural stability from the assembly stage. The overall solution does not rely on external energy or complex circuitry, retaining all the mechanical functions of a traditional cap while providing self-indicating and expandable monitoring capabilities, making it suitable for high-vibration, wide-temperature-varying, and power-free field oil extraction environments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0026] Figure 2 This is a partially enlarged view of the mating structure between the main cap body and the axial limiting ring according to an embodiment of this application;

[0027] Figure 3 This is a schematic diagram showing the assembly relationship of the spiral guide groove seat, radial indicator rod, and end face scale of this utility model.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Main cap body; 2. Axial limiting ring; 3. Radial indicator rod; 4. Spiral guide groove seat; 5. End face dial; 6. Annular boss; 7. Annular groove; 8. Positioning protrusion; 9. Spiral groove; 10. Pointer head; 11. Fixed bracket; 12. Angle scale line; 13. Displacement scale; 14. Annular sealing groove; 15. Oil-resistant rubber sealing ring; 16. Magnetic marking block; 17. Guide through hole; 18. PTFE bushing; 19. Roller structure; 20. Fluorescent coating; 21. Annular slot; 22. Anti-rotation baffle; 23. Annular light-shielding awning; 24. Chamfered transition section; 25. Overlapping tongue; 26. Countersunk screw; 27. Process screw hole. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] Please see Figures 1 to 3 This utility model provides an intelligent monitoring and anti-loosening oil wellhead cap. The cap is used at the wellhead tubing connection point in oil extraction sites. Through a mechanical structure, it realizes continuous sensing and visual indication of axial displacement during the service of the cap. At the same time, it retains the physical basis for interfacing with a remote sensing system. It is suitable for field operation environments with high vibration, wide temperature variation, and no external energy supply.

[0032] The main cap body 1 is a cylindrical metal component, forged from high-strength alloy steel and then machined, heat-treated, and surface phosphated. Its inner wall has an internal thread section that matches the external thread of the wellhead tubing. The end of the internal thread section has a chamfered transition section 24 with an angle of 30 degrees, used to guide the tubing thread into the machine smoothly and reduce the risk of thread damage during assembly. A ring-shaped boss 6 is arranged around the middle of the outer wall of the main cap body 1. An annular groove 7, three millimeters deep and five millimeters wide, is formed on the upper surface of the annular boss 6 to accommodate the axial limiting ring 2. An annular groove 21 is located near the bottom of the outer wall of the main cap body 1. 21. An anti-rotation baffle 22 is inserted into the positioning hole of the wellhead base to limit the free rotation of the main cap 1 when it is not subjected to external force. The top end face of the main cap 1 is provided with an annular sealing groove 14, and an oil-resistant rubber sealing ring 15 is embedded in the annular sealing groove 14. The oil-resistant rubber sealing ring 15 has a circular cross-section and a diameter of four millimeters. After the cap is tightened, it forms a sealing interface with the wellhead flange end face to prevent fluid in the well from leaking out along the thread gap. The outer wall of the main cap 1 is provided with a process screw hole 27, which penetrates the wall thickness of the main cap 1 and communicates with the bottom of the internal thread section. It is used to inject grease during the manufacturing process to reduce the friction coefficient of the thread pair.

[0033] The axial limiting ring 2 is an open elastic metal ring made of spring steel strip through stamping, rolling, and heat treatment. Its outer diameter is slightly larger than the inner diameter of the annular groove 7 by 0.2 mm. After assembly, it is embedded in the annular groove 7 and maintains pre-tightening pressure to limit the axial displacement of the main cap 1 relative to the tubing. The opening of the axial limiting ring 2 is provided with an overlapping tongue 25. Both ends of the overlapping tongue 25 are provided with through holes. The overlapping tongue 25 is locked by countersunk screws 26, so that the axial limiting ring 2 forms a complete closed-loop structure after installation, enhancing its axial constraint capability. The top plane of the axial limiting ring 2 is provided with multiple positioning protrusions 8 evenly distributed along the circumference. There are eight positioning protrusions 8, and each positioning protrusion 8 has the same height of 0.5 mm, which is used to contact the bottom of the spiral guide seat 4 to form an initial reference position.

[0034] The spiral guide seat 4 is a ring-shaped metal component made of stainless steel plate, machined by turning and milling. It is fitted onto the outer wall of the main cap body 1 and located above the annular boss 6. Its lower surface contacts the positioning protrusion 8 of the axial limiting ring 2. Its inner wall has a guide surface that slides with the outer wall of the main cap body 1. A 0.1 mm gap is reserved between the guide surface and the outer wall of the main cap body 1 to ensure that the spiral guide seat 4 can rotate freely around the axis of the main cap body 1. The outer wall of the spiral guide seat 4 is machined with a continuous spiral groove 9. The pitch of the spiral groove 9 is constant at 2 mm, and the direction of rotation is opposite to that of the internal thread of the main cap body 1. The central area of ​​the upper surface of the spiral guide seat 4 has an annular step. The outer diameter of the annular step is 8 mm smaller than the outer diameter of the main body of the spiral guide seat 4, and the height is 2 mm. It is used to support the spiral guide seat 4. The end face dial 5 to be installed; the upper surface edge of the spiral guide groove seat 4 is provided with an annular light-shielding awning 23, which extends downward by 10 mm and covers the outer edge area of ​​the end face dial 5, in order to block strong external light from shining directly on the scale surface and improve the clarity of reading; the bottom of the spiral guide groove seat 4 is provided with an annular guide rail, which cooperates with the annular sliding groove on the outer wall of the main cap body 1 to ensure that the spiral guide groove seat 4 can only rotate and not deviate radially when subjected to axial force; the outer wall of the spiral guide groove seat 4 is also provided with a magnetic marking block 16, which is fixed to the outer wall of the spiral guide groove seat 4 and does not overlap with the spiral groove 9. Its position is aligned with the initial zero point of the radial indicator rod 3. The magnetic marking block 16 is made of neodymium iron boron material and is covered with a stainless steel shell to prevent corrosion.

[0035] The radial indicator rod 3 is a slender, rigid metal rod made of hard aluminum alloy bar that has been machined and polished. One end of the rod has a roller structure 19, which consists of a miniature bearing and an outer nylon wheel. The inner ring of the miniature bearing is interference-fitted with the end of the radial indicator rod 3, and the outer ring of the nylon wheel contacts the side walls of the spiral groove 9 to ensure smooth rolling without jamming. The other end of the radial indicator rod 3 extends to the outer space of the main cap body 1 and is fixedly connected to the pointer head 10. The pointer head 10 is made of hollow aluminum alloy tubing and filled with lightweight foam material to reduce the overall weight and avoid indication deviation due to its own weight. The radial indicator rod 3 passes through the middle. The fixed bracket 11 is an L-shaped metal plate. Its vertical section is welded to the outer wall of the main cap body 1, and its horizontal section is provided with a guide hole 17. The axis of the guide hole 17 is perpendicular to the axis of the main cap body 1. The inner wall of the guide hole 17 is inlaid with a polytetrafluoroethylene bushing 18. The polytetrafluoroethylene bushing 18 has a thickness of 0.5 mm and a length of 15 mm to reduce the frictional resistance when the radial indicator rod 3 slides. The top of the horizontal section of the fixed bracket 11 is provided with a protective cover. The protective cover is a semi-cylindrical metal plate with both ends welded to the vertical section of the fixed bracket 11. It is used to cover the exposed part of the radial indicator rod 3 to prevent external impact or foreign objects from getting entangled.

[0036] The end face dial 5 is a circular transparent plastic plate made of polycarbonate sheet through laser cutting, printing, and bonding processes. Its bottom surface is bonded to the upper surface of the annular step of the spiral guide groove seat 4. Its top surface is printed with angle scale lines 12 and displacement scale 13. The angle scale lines 12 are radially distributed with the center as the reference, with a main scale line every ten degrees and a secondary scale line every degree. The displacement scale 13 is arranged along the circumference and corresponds to the pitch parameter of the spiral guide groove 9. Each millimeter of displacement corresponds to 180 degrees. The end face dial 5 has a through hole at its center, the diameter of which is five millimeters larger than the outer diameter of the main cap 1, to ensure that the spiral guide seat 4 is not interfered with when it rotates; the edge of the end face dial 5 is provided with a fluorescent coating 20, which covers the digital area of ​​the angle scale line 12 and the displacement scale 13, so that the reading can still be identified in low light environment; the back of the end face dial 5 is provided with a calibration mark line, which is aligned with the reference scale line on the spiral guide seat 4, and is used to confirm the zero position accuracy during the assembly process.

[0037] The assembly process is as follows: First, embed the oil-resistant rubber sealing ring 15 into the annular sealing groove 14 at the top of the main cap body 1; then, place the axial limiting ring 2 into the annular groove 7, adjust the position of the overlapping tongue 25, and lock it with the countersunk screw 26 to form a closed loop; next, put the spiral guide seat 4 from the top of the main cap body 1, so that its lower surface contacts the positioning protrusion 8 of the axial limiting ring 2, and at the same time ensure that the annular guide rail at the bottom of the spiral guide seat 4 is aligned with the annular sliding groove on the outer wall of the main cap body 1; then, the radial... The roller structure 19 of the indicator rod 3 is embedded into the spiral groove 9 on the outer wall of the spiral guide seat 4. Then, the radial indicator rod 3 is passed through the guide through hole 17 of the fixed bracket 11, so that the fixed bracket 11 is welded to the designated position on the outer wall of the main cap body 1. After that, the end face scale 5 is glued to the upper surface of the annular step of the spiral guide seat 4, and the position is adjusted so that the calibration mark line on the back is aligned with the reference line on the spiral guide seat 4. Finally, the anti-rotation baffle 22 is snapped into the annular slot 21 on the outer wall of the main cap body 1 to complete the overall assembly.

[0038] During operation, when the main cap 1 experiences a slight axial displacement due to vibration or temperature changes, this displacement is transmitted to the axial limiting ring 2 via the annular boss 6. The axial limiting ring 2 pushes the spiral guide seat 4 to move axially. Since the pitch of the spiral groove 9 is constant and its direction of rotation is opposite to that of the internal thread of the main cap 1, the spiral guide seat 4 is forced to rotate around the axis of the main cap 1. The rotation angle is proportional to the amount of axial displacement. The rotation of the spiral guide seat 4 drives the spiral groove 9 on its outer wall to rotate synchronously. The roller structure 19 rolls within the spiral groove 9, forcing the radial indicator rod 3 to move along the fixed bracket 11. The guide hole 17 moves radially; the pointer 10 at the other end of the radial indicator rod 3 moves on the surface of the end face dial 5, pointing to different angle scale lines 12 and displacement scale 13. The operator can visually read the scale value indicated by the pointer 10 and calculate the actual axial displacement of the main cap body 1. If a remote monitoring system is required, a non-contact angle sensor can be installed at the corresponding position of the magnetic marker block 16. The sensor senses the change in the rotation angle of the magnetic marker block 16 and outputs an electrical signal to the data acquisition terminal to realize the electronic recording and early warning of the loose state.

[0039] Under extreme lighting conditions, the fluorescent coating 20 on the edge of the end face dial 5 provides auxiliary illumination to ensure clear visibility of the scale; the annular shading 23 blocks direct sunlight or strong reflected light to avoid glare interfering with reading accuracy; the protective cover protects the radial indicator rod 3 from external impacts or debris entanglement, maintaining smooth movement of the mechanism; the process screw hole 27 is injected with high-temperature grease before leaving the factory to reduce thread friction and extend service life; the chamfered transition section 24 ensures smooth thread entry during assembly and reduces thread profile damage; the anti-rotation baffle 22 cooperates with the wellhead base positioning hole to prevent the pressure cap from rotating unexpectedly when not under load; the overlapping tongue 25 and the countersunk screw 26 combine to strengthen the overall rigidity of the axial limiting ring 2 and improve axial constraint stability.

[0040] The dimensional tolerances of each component are strictly controlled: the tolerance for the fit between the internal thread section of the main cap body 1 and the external thread of the wellhead tubing is H7 / g6; the tolerance for the fit between the inner diameter of the annular groove 7 and the outer diameter of the axial limiting ring 2 is H8 / h7; the gap between the inner guide surface of the spiral guide seat 4 and the outer wall of the main cap body 1 is controlled within the range of 0.05 to 0.15 mm; the gap between the outer diameter of the roller structure 19 and the width of the spiral groove 9 is 0.03 mm; the gap between the inner diameter of the guide through hole 17 and the outer diameter of the radial indicator rod 3 is 0.02 mm; the gap between the inner diameter of the through hole of the end face dial 5 and the outer diameter of the main cap body 1 is 5 mm ± 0.5 mm; all welded parts adopt argon arc welding process, the weld height is not less than 3 mm, and there are no defects such as porosity or slag inclusion; all bonded parts use high-temperature resistant epoxy resin adhesive, and the shear strength after curing is not less than 20 MPa.

[0041] The intelligent monitoring and anti-loosening oil wellhead cap of this utility model has a structural design that meets the requirements for long-term stable operation under harsh field conditions. It does not require external power supply or complex circuit support, and relies on pure mechanical transmission to realize displacement sensing and visual indication. At the same time, it reserves a magnetic marker block 16 as an interface for future intelligent upgrades, which facilitates the subsequent addition of angle sensors to realize data transmission. It takes into account both practicality and scalability, and is suitable for wellhead connection parts of various onshore and offshore oil extraction platforms.

[0042] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An intelligent monitoring and anti-loosening cap for oil extraction, characterized in that, It includes a main cap body (1), an axial limiting ring (2), a radial indicator rod (3), a spiral guide groove seat (4), and an end face dial (5), wherein: The main cap body (1) is a cylindrical metal component with an internal thread section on its inner wall that matches the external thread of the wellhead pipe string, and an annular boss (6) is arranged around the middle of its outer wall, with an annular groove (7) on the upper surface of the annular boss (6). The axial limiting ring (2) is an open elastic metal ring that is embedded in an annular groove (7) and has multiple positioning protrusions (8) evenly distributed along the circumference on its top plane. The spiral guide groove seat (4) is sleeved on the outer wall of the main cap body (1) and located above the annular boss (6). Its lower surface is in contact with the positioning protrusion (8). Its outer wall is provided with a continuous spiral groove (9). The pitch of the spiral groove (9) is constant and the direction of rotation is opposite to the direction of rotation of the internal thread of the main cap body (1). The radial indicator rod (3) has a roller structure (19) at one end, which is embedded in the spiral groove (9), and the pointer head (10) is fixedly connected to the other end. The radial indicator rod (3) passes through the fixed bracket (11) in the middle, and the fixed bracket (11) is welded to the outer wall of the main cap body (1). The end face dial (5) is bonded to the upper surface of the spiral guide groove seat (4), and its top surface is printed with angle scale lines (12) and displacement scale (13), and the pointer head (10) points to the scale area of ​​the end face dial (5).

2. The intelligent monitoring and anti-loosening oil extraction cap according to claim 1, characterized in that: The top end face of the main cap body (1) is provided with an annular sealing groove (14), and an oil-resistant rubber sealing ring (15) is embedded in the annular sealing groove (14).

3. The intelligent monitoring and anti-loosening oil extraction cap according to claim 1, characterized in that: The outer wall of the spiral guide groove seat (4) is provided with a magnetic marker block (16), and the position of the magnetic marker block (16) is aligned with the initial zero point of the radial indicator rod (3).

4. The intelligent monitoring and anti-loosening oil extraction cap according to claim 1, characterized in that: The fixed bracket (11) is an L-shaped metal plate with a guide hole (17) in its horizontal section. The inner wall of the guide hole (17) is inlaid with a polytetrafluoroethylene bushing (18).

5. The intelligent monitoring and anti-loosening oil extraction cap according to claim 1, characterized in that: The roller structure (19) consists of a miniature bearing and an outer nylon wheel, with the inner ring of the miniature bearing having an interference fit with the end of the radial indicator rod (3).

6. The intelligent monitoring and anti-loosening oil extraction cap according to claim 1, characterized in that: The edge of the end face dial (5) is provided with a fluorescent coating (20), which covers the digital area of ​​the angle scale line (12) and the displacement scale (13).

7. The intelligent monitoring and anti-loosening oil extraction cap according to claim 1, characterized in that: The outer wall of the main cap (1) near the bottom is provided with an annular groove (21), and an anti-rotation baffle (22) is engaged in the annular groove (21).

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