A device for controlling the over-pouring height of a cast-in-place pile concrete

Abstract

The application relates to a cast-in-place pile concrete over-pouring height control device, belonging to the technical field of pile foundation engineering construction, which comprises an inner pipe and an outer pipe, the inner pipe is arranged in the outer pipe, the inner pipe is rotatably arranged in the outer pipe, the side wall of the outer pipe is provided with an outer pipe ash inlet, and the side wall of the inner pipe is provided with an inner pipe ash inlet; the outer pipe ash inlet and the inner pipe ash inlet are completely overlapped to form a sampling channel or are completely dislocated to close the sampling channel by rotating the inner pipe. The device is simple to operate, the opening and closing of the sampling channel are controlled through the rotating cooperation of the inner pipe and the outer pipe, the over-pouring height of the pile top concrete can be accurately controlled, excessive pouring is avoided, material waste and construction cost are reduced, meanwhile, the removed concrete sample can help to judge the quality of the pile head concrete, if an abnormality is found, the pouring scheme can be timely adjusted, the quality of the pile head is ensured to meet the design requirements, and the construction quality and efficiency are improved.

Description

Technical Field

[0001] This application relates to the field of pile foundation construction technology, and in particular to a device for controlling the over-pouring height of cast-in-place pile concrete. Background Technology

[0002] In foundation engineering construction, diaphragm walls and bored piles are common main structural components used to provide stable bearing capacity and ensure the safety and stability of buildings. To improve the quality and bearing capacity of pile foundations, over-pouring technology is usually adopted, which involves pouring concrete to a certain height above the design pile top elevation. Standards typically require that the concrete at the pile top should be 0.5-1 meter higher than the design elevation.

[0003] Although over-grouting technology can effectively ensure the quality of pile foundations, some challenges still exist in actual construction. First, the thickness of the laitance in the pile top concrete is difficult to control precisely. Construction workers often find it difficult to accurately measure and control the actual height of the pile head concrete, leading to quality problems such as mud and sand inclusions in the pile head concrete during construction, which affects the stability and bearing capacity of the pile foundation.

[0004] Secondly, traditional grouting methods rely on the experience of construction workers and lack scientific and accurate control methods. Due to the lack of effective technical means to control the over-grouting height, the pile head concrete is often over-grown in actual construction, exceeding the design requirements, resulting in a waste of concrete resources and increased construction costs.

[0005] Therefore, it is urgent to solve these problems through innovative technologies and devices that can accurately control the over-pouring height of concrete while ensuring the quality of the concrete at the top of the pile, and avoid resource waste and reduce costs. Utility Model Content

[0006] In order to control the over-pouring height of concrete at the top of the pile, reduce resource waste, ensure the quality of concrete at the top of the pile while reducing construction costs, this application provides a device for controlling the over-pouring height of concrete in cast-in-place piles.

[0007] The technical solution of the over-pouring height control device for cast-in-place pile concrete provided in this application is as follows: A device for controlling the over-pouring height of cast-in-place concrete includes an inner pipe and an outer pipe. The inner pipe is installed inside the outer pipe and is rotatably disposed inside the outer pipe. The side wall of the outer pipe is provided with an outer pipe ash inlet, and the side wall of the inner pipe is provided with an inner pipe ash inlet. By rotating the inner pipe, the ash inlets of the outer pipe and the inner pipe can be completely overlapped to form a sampling channel, or the sampling channel can be completely misaligned to close it.

[0008] By adopting the above technical solution, the device is easy to use and quick to operate, requiring minimal manual intervention. The opening and closing of the sampling channel can be controlled by the rotation of the inner and outer pipes, ensuring that the sampling height of the concrete passing through represents the actual over-pouring height at the pile top. This effectively monitors the over-pouring height of the concrete at the top of the cast-in-place pile. Accurate measurement prevents excessive concrete pouring, reducing waste and saving materials, thus lowering construction costs. Furthermore, by observing the quality of the extracted concrete samples, the quality of the pile head concrete can be assessed. If abnormalities are found, the pouring plan can be adjusted promptly to ensure the pile head quality meets design requirements, thereby improving construction quality and efficiency.

[0009] In one specific implementation, the inner tube extends out of the outer tube along the height direction and has a rotating portion.

[0010] By adopting the above technical solution and utilizing the design of the rotating part, users can easily adjust the docking position of the inner tube and the ash inlet of the outer tube by rotating the rotating part of the inner tube. The operation is simple and flexible, and the opening and closing of the sampling channel can be easily controlled.

[0011] In one specific implementation, an outer tube alignment line is provided on the outer wall of one side of the top of the outer tube, and an inner tube alignment line is provided on the outer wall of the rotating part. The outer tube alignment line and the inner tube alignment line are used in conjunction to indicate the overlapping position of the ash inlet of the outer tube and the ash inlet of the inner tube.

[0012] By adopting the above technical solution, the alignment line of the outer tube and the alignment line of the inner tube are used together to provide intuitive and accurate alignment instructions, making the docking of the inner tube and the ash inlet of the outer tube simpler and more accurate, thereby avoiding poor docking due to operational errors, and thus improving the accuracy and convenience of operation.

[0013] In one specific implementation, the rotating part is provided with an operating handle.

[0014] By adopting the above technical solution, the operation is made more convenient by equipping the operating handle. Users can easily adjust the position of the inner tube and the outer tube by rotating the handle. The operating handle can provide better control and comfort, and avoid inaccurate operation caused by difficulty in manual adjustment.

[0015] In one specific implementation, the outer wall of the outer tube is provided with scale markings, which are set along the height direction of the outer tube to control the insertion of the outer tube to the designed pile top position and to indicate the concrete sampling height.

[0016] By adopting the above technical solution and using the scale markings, operators can control the insertion depth of the outer tube, ensuring that the insertion position of the outer tube is consistent with the designed pile top position, thereby avoiding sampling errors caused by inaccurate insertion depth. It can also indicate the sampling height of the extracted concrete. Operators can observe the accurate height of the sample extraction according to the scale markings, determine whether the over-pouring height of the concrete meets the predetermined standard, and whether the pouring process needs to be adjusted to avoid quality problems.

[0017] In one specific implementation scheme, the top ends of the outer tube and the inner tube are open structures, and the bottom ends are closed structures.

[0018] By adopting the above technical solution, the open top design allows the inner tube to rotate easily inside the outer tube. The bottom ends of both the outer and inner tubes are closed structures, preventing concrete leakage or overflow during sampling, thus ensuring sample integrity and improving sampling accuracy.

[0019] In one specific implementation scheme, there is a distance between the bottom end of the outer tube ash inlet and the bottom end of the outer tube, and the bottom end of the inner tube ash inlet is flush with the bottom end of the inner tube.

[0020] By adopting the above technical solution, the distance between the bottom end of the outer pipe inlet and the bottom end of the outer pipe can be designed to avoid contamination of the sampling area by sediment at the bottom of the pipe, so that the material entering the sampling channel will not be disturbed by the sediment at the bottom, thereby improving the accuracy of sampling. The bottom end of the inner pipe inlet is flush with the bottom end of the inner pipe. When the inlets of the inner and outer pipes are completely overlapped, the maximum opening can be opened to ensure that the concrete can smoothly enter the sampling space, thereby improving the reliability of sampling and avoiding the risk of material flow obstruction.

[0021] In one specific implementation, the outer tube ash inlet and the inner tube ash inlet are of the same size.

[0022] By adopting the above technical solution, and utilizing the fact that the inlets of the outer and inner pipes are exactly the same size, accurate docking of the inlets can be achieved when the inner pipe is rotated, thereby effectively controlling the pouring height of the concrete, ensuring that the pouring height meets the design standards, and avoiding concrete waste.

[0023] In one specific implementation, the outer wall of the inner tube is provided with a limiting protrusion, and the inner wall of the outer tube is provided with an annular groove, with the limiting protrusion rotatably disposed within the annular groove.

[0024] By adopting the above technical solution, the structural design of the limiting protrusion and the annular groove ensures that the relative movement of the inner tube in the outer tube is controlled, preventing the inner tube from slipping or falling off, and maintaining the stable position of the inner tube in the outer tube, thereby making the entire device more reliable during use.

[0025] In one specific implementation, a fixing member is provided in the annular groove, which is used to fix the limiting protrusion when the ash inlet of the outer tube and the ash inlet of the inner tube are completely overlapped. The fixing component includes a groove on the side wall of the annular groove, a spring and a positioning bead in the groove. One end of the spring is connected to the bottom wall of the groove, and the other end is connected to the positioning bead. The limiting protrusion is provided with a fixing groove for the positioning bead to slide into and fix.

[0026] By adopting the above technical solution, the solution ensures that the ash inlets of the inner tube and the outer tube always remain completely aligned through an automatic locking mechanism; the fixing process of the inner tube inside the outer tube is guaranteed by the cooperation of the positioning bead and the spring, and the limiting protrusion is firmly fixed by the fixing groove to avoid the slippage or falling off of the inner tube, so that the ash inlets of the inner tube and the outer tube are always accurately connected, ensuring accurate sampling during operation.

[0027] In summary, the beneficial technical effects of this application are as follows: The device of this application accurately controls the opening and closing of the sampling channel through the rotation and cooperation of the inner and outer tubes, thereby achieving effective control of the over-pouring height of the concrete at the top of the cast-in-place pile. Through simple operation, it can avoid excessive concrete pouring, reduce waste, and ensure that the height of the sample reflects the actual concrete height at the pile head, thereby improving construction quality and efficiency, while saving materials and reducing costs. In addition, the device is designed with a reliable positioning and locking mechanism, including precise docking of the ash inlet of the outer tube and the inner tube, operating handle, scale markings and limit protrusions, etc., to ensure that the inner and outer tubes are stable in position during operation and avoid misoperation; through the automatic locking and fixing mechanism, the position of the inner tube is stabilized, thereby ensuring the accuracy of sampling and improving the convenience and accuracy of operation. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the concrete over-pouring height control device for cast-in-place piles in Example 1.

[0029] Figure 2 This is a schematic diagram illustrating the structure of the operating handle in Embodiment 2.

[0030] Figure 3 This is a cross-sectional view used to illustrate the limiting protrusion and annular groove in Embodiment 3.

[0031] Figure 4 It is a longitudinal section view used to show the limiting protrusion, annular groove, and fastener in Embodiment 4.

[0032] Figure 5 This is an enlarged view used to illustrate the fastener in Example 4.

[0033] Explanation of reference numerals in the attached drawings: 1. Inner tube; 11. Inner tube ash inlet; 12. Inner tube alignment line; 2. Outer tube; 21. Outer tube ash inlet; 22. Outer tube alignment line; 23. Scale markings; 3. Rotating part; 31. Operating handle; 4. Limiting protrusion; 5. Annular groove; 6. Fixing element; 61. Groove; 62. Spring; 63. Positioning bead. Detailed Implementation

[0034] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0035] Example 1 Reference Figure 1 This application discloses a device for controlling the over-pouring height of cast-in-place pile concrete, including an inner pipe 1 and an outer pipe 2. The inner pipe 1 is installed inside the outer pipe 2 and is rotatably disposed inside the outer pipe 2. In this embodiment, the inner pipe 1 extends out of the outer pipe 2 along the height direction and forms a rotating part 3. The rotation of the inner pipe 1 is achieved through the rotating part 3. The outer tube 2 has an outer tube ash inlet 21 on its side wall, and the inner tube 1 has an inner tube ash inlet 11 on its side wall. The outer tube ash inlet 21 and the inner tube ash inlet 11 are arranged along the height direction. In this embodiment, the outer tube ash inlet 21 and the inner tube ash inlet 11 are the same in size and shape. The outer tube ash inlet 21 and the inner tube ash inlet 11 include, but are not limited to, rectangular openings with a width of 5cm and a height of 60cm. With the design of being exactly the same in shape and size, the outer tube ash inlet 21 and the inner tube ash inlet 11 can be accurately connected when the inner tube 1 is rotated, ensuring the accuracy of opening and closing the sampling channel. By rotating the inner tube 1, the positional relationship between the outer tube inlet 21 and the inner tube inlet 11 is adjusted so that the outer tube inlet 21 and the inner tube inlet 11 completely overlap to form a sampling channel, or completely offset to close the sampling channel; thereby realizing the opening and closing control of the sampling channel, ensuring the accurate measurement of the concrete over-pouring height, avoiding excessive concrete pouring, reducing material waste, lowering construction costs, and improving construction quality and efficiency.

[0036] An outer pipe alignment line 22 is provided on the outer wall of the top side of the outer pipe 2, and an inner pipe alignment line 12 is provided on the outer wall of the rotating part 3 of the inner pipe 1. The outer pipe alignment line 22 and the inner pipe alignment line 12 are used together to indicate the overlapping position of the outer pipe ash inlet 21 and the inner pipe ash inlet 11, providing accurate docking indication. During the rotation of the inner pipe 1, when the outer pipe alignment line 22 and the inner pipe alignment line 12 are completely aligned, it indicates that the outer pipe ash inlet 21 and the inner pipe ash inlet 11 have been completely overlapped and docked. At this time, the sampling channel is opened to allow concrete to flow in. When the alignment lines are completely misaligned, the sampling channel is closed to prevent concrete from flowing in.

[0037] The outer wall of the outer tube 2 is provided with a scale mark 23, which is set along the height direction of the outer tube 2. On the one hand, the scale mark 23 is used to indicate the depth of the outer tube 2 inserted to the designed pile top position. The operator can control the insertion depth of the outer tube 2 according to the scale mark 23 to ensure that its insertion position is consistent with the designed pile top position and avoid sampling errors caused by inaccurate insertion depth. On the other hand, the scale mark 23 can also be used to indicate the sampling height of the extracted concrete. The operator can observe the position of the top surface of the extracted concrete according to the scale mark 23 and read the sampling height, thereby judging whether the over-pouring height of the concrete meets the predetermined standard, and thus adjusting the concrete pouring volume to ensure quality and height control.

[0038] In this embodiment, the inner tube 1 and the outer tube 2 have open tops and closed bottoms, which allows the inner tube 1 to rotate inside the outer tube 2. Furthermore, the closed bottom design of the inner tube 1 and the outer tube 2 can prevent concrete from leaking or overflowing during the sampling process, ensuring the integrity of the sample and ensuring the efficiency and accuracy of the entire sampling process.

[0039] A distance is left between the bottom end of the outer pipe ash inlet 21 and the bottom end of the outer pipe 2. In this embodiment, the distance between the bottom end of the outer pipe ash inlet 21 and the bottom end of the outer pipe 2 includes, but is not limited to, 1-3 cm. This design can effectively avoid the contamination of the sampling area by the sediment at the bottom of the pipe, ensure that the concrete entering the sampling channel is not disturbed by the sediment at the bottom, and improve the accuracy of sampling. The bottom end of the inner pipe ash inlet 11 is flush with the bottom end of the inner pipe 1, thereby ensuring the accurate position of the ash inlet. When the inner and outer pipe ash inlets 21 are completely overlapped, they can be opened to the maximum degree, ensuring that the concrete can smoothly enter the sampling space, thereby improving the reliability of sampling and avoiding the risk of material flow obstruction.

[0040] The implementation principle of this application embodiment is as follows: In the actual construction process, the device is first inserted into the designed pile top position of the cast-in-place pile. During this process, the insertion depth of the outer tube 2 can be controlled by the scale mark 23 to ensure that its insertion position is consistent with the designed pile top position, so that the outer tube 2 is accurately inserted into the designed pile top position of the cast-in-place pile. When sampling, the inner tube 1 is rotated to observe the positional relationship between the alignment line 22 of the outer tube and the alignment line 12 of the inner tube. When the alignment line 22 of the outer tube and the alignment line 12 of the inner tube are completely aligned, it indicates that the ash inlet 21 of the outer tube and the ash inlet 11 of the inner tube have completely overlapped and connected, so that the ash inlet 21 of the outer tube and the ash inlet 11 of the inner tube are completely overlapped, forming a sampling channel. At this time, the concrete enters the equipment through the sampling channel, and after a 3-second time interval, the concrete is sampled. After sampling, rotate the inner tube 1 and observe the positional relationship between the alignment line 22 of the outer tube and the alignment line 12 of the inner tube. When the alignment lines are completely misaligned, the ash inlet 11 of the inner tube and the ash inlet 21 of the outer tube are completely misaligned, closing the sampling channel and preventing concrete from continuing to pass through. The sampling height of the concrete sample taken at this time is the over-pouring height of the concrete at the top of the pile. During this process, the sampling height can be read according to the scale mark 23 to determine whether the over-pouring height meets the predetermined standard (0.5-1m). This device is easy to use and operates quickly, requiring minimal manual intervention. Throughout the operation, the rotation of the inner tube 1 and outer tube 2 controls the precise alignment of the inner tube's ash inlet 11 with the outer tube's ash inlet 21, ensuring the sampling height matches the actual over-pouring height of the cast-in-place pile. This effectively monitors the over-pouring height of the concrete, preventing excessive concrete pouring, reducing waste, saving materials, and lowering construction costs. Simultaneously, the quality of the extracted concrete sample can be used to determine the quality of the pile head concrete. If any abnormalities are found, operators can promptly adjust the pouring plan to ensure the pile head quality meets design requirements, thereby improving construction quality and efficiency.

[0041] Example 2 Reference Figure 2 The difference between this embodiment and embodiment 1 is that an operating handle 31 is provided on the outer side wall of the rotating part 3; the operator can easily adjust the rotation angle of the inner tube 1 by rotating the operating handle 31, thereby adjusting the position of the inner tube 1 and the ash inlet 21 of the outer tube; the design of the rotating part 3 makes the whole operation process more convenient, reduces the complexity of operation, provides better control and comfort, and avoids inaccurate operation caused by difficulty in manual adjustment.

[0042] Example 3 Reference Figure 3 The difference between this embodiment and embodiment 1 is that the outer side wall of the inner tube 1 is provided with a limiting protrusion 4, and the inner side wall of the outer tube 2 is provided with an annular groove 5. The annular groove 5 is arranged along the circumferential direction of the inner wall of the outer tube 2, and the limiting protrusion 4 is rotatably arranged in the annular groove 5. The structural design of the limiting protrusion 4 and the annular groove 5 can ensure that the relative movement of the inner tube 1 in the outer tube 2 is controlled. Even during rotation, the inner tube 1 will not slip or fall off, maintaining the stable position of the inner tube 1 in the outer tube 2. This makes the whole device more reliable during use and avoids malfunctions or misoperations caused by the unstable position of the inner tube 1.

[0043] Example 4 Reference Figure 4 and Figure 5The difference between this embodiment and embodiment 3 is that a fixing member 6 is also provided in the annular groove 5. The fixing member 6 includes a groove 61 on the side wall of the annular groove 5, a spring 62 and a positioning bead 63 in the groove 61. One end of the spring 62 is connected to the bottom wall of the groove 61, and the other end is connected to the positioning bead 63. The limiting protrusion 4 is provided with a fixing groove for the positioning bead 63 to slide into and be fixed. When the outer tube ash inlet 21 and the inner tube ash inlet 11 are completely overlapped, the limiting protrusion 4 and the positioning bead 63 cooperate, and the positioning bead 63 slides into the fixing groove by the action of the spring 62, fixing the position of the limiting protrusion 4, thereby stabilizing the inner tube 1 and ensuring that the outer tube ash inlet 21 and the inner tube ash inlet 11 are accurately connected.

[0044] The implementation principle of Example 4 is as follows: During the sampling process, the inner tube 1 is rotated, and the limiting protrusion 4 on the inner tube 1 rotates within the annular groove 5, restricting the position of the inner tube 1. During the rotation, the outer tube ash inlet 21 gradually overlaps with the inner tube ash inlet 11. As the inner tube 1 rotates, the limiting protrusion 4 rotates until it gradually aligns with the groove 61 on the side wall of the annular groove 5. The limiting protrusion 4 will first squeeze the positioning bead 63 and the spring 62, and the spring 62 will compress and store force. The inner tube 1 continues to rotate, and when the outer tube ash inlet... When the outer tube ash inlet 21 is completely aligned with the inner tube ash inlet 11, the positioning bead 63 encounters the fixing groove on the limiting protrusion 4. The positioning bead 63 slides into the fixing groove and is fixed by the action of the spring 62, which firmly fixes the limiting protrusion 4 in the annular groove 5, ensuring that the position of the inner tube 1 remains stable. After the inner tube 1 is stably fixed, the outer tube ash inlet 21 and the inner tube ash inlet 11 are in a completely aligned state. At this time, the ash inlets between the inner and outer tubes 2 are always completely aligned, ensuring that the sampling is accurate during the operation. After sampling, the inner tube 1 is rotated again. As the inner tube 1 rotates, the limiting protrusion 4 begins to rotate and gradually disengages from the alignment position with the groove 61 on the side wall of the annular groove 5. The limiting protrusion 4 squeezes the positioning bead 63 and the spring 62 into the groove 61, disengaging from the fixing groove on the limiting protrusion 4 and releasing the lock on the limiting protrusion 4. When the limiting protrusion 4 rotates to the point where it is completely disaligned with the groove 61, the originally compressed spring 62 gradually returns to its original state, pushing the positioning bead 63 to move outward and return to its original position in the annular groove 5. During sampling, an automatic locking mechanism is used to ensure that the inner tube 1 and the outer tube ash inlet 21 are always in a completely overlapping position. Through the cooperation of the positioning bead 63 and the spring 62, the fixing process of the inner tube 1 in the outer tube 2 is guaranteed. The limiting protrusion 4 is firmly fixed by the fixing groove to avoid the slippage or falling off of the inner tube 1, so that the inner tube ash inlet 11 and the outer tube ash inlet 21 are always accurately connected, ensuring accurate sampling during operation.

[0045] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A device for controlling the over-pouring height of concrete in cast-in-place piles, characterized in that: It includes an inner tube (1) and an outer tube (2). The inner tube (1) is installed inside the outer tube (2). The inner tube (1) is rotatably disposed inside the outer tube (2). The side wall of the outer tube (2) is provided with an outer tube ash inlet (21), and the side wall of the inner tube (1) is provided with an inner tube ash inlet (11). By rotating the inner tube (1), the outer tube ash inlet (21) and the inner tube ash inlet (11) are completely overlapped to form a sampling channel, or the sampling channel is completely misaligned and closed.

2. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 1, characterized in that: The inner tube (1) extends out of the outer tube (2) along the height direction and has a rotating part (3).

3. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 2, characterized in that: The outer tube (2) has an outer tube alignment line (22) on one side of the top, and the rotating part (3) has an inner tube alignment line (12) on its outer wall. The outer tube alignment line (22) and the inner tube alignment line (12) are used together to indicate the overlapping position of the outer tube ash inlet (21) and the inner tube ash inlet (11).

4. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 2, characterized in that: The rotating part (3) is provided with an operating handle (31).

5. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 1, characterized in that: The outer wall of the outer tube (2) is provided with a scale mark (23), which is set along the height direction of the outer tube (2) to control the insertion of the outer tube (2) to the designed pile top position and to indicate the concrete sampling height.

6. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 1, characterized in that: The top ends of the outer tube (2) and the inner tube (1) are open, and the bottom ends are closed.

7. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 1, characterized in that: There is a distance between the bottom end of the outer tube ash inlet (21) and the bottom end of the outer tube (2), and the bottom end of the inner tube ash inlet (11) is flush with the bottom end of the inner tube (1).

8. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 1, characterized in that: The outer tube ash inlet (21) has the same size as the inner tube ash inlet (11).

9. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 1, characterized in that: The outer wall of the inner tube (1) is provided with a limiting protrusion (4), and the inner wall of the outer tube (2) is provided with an annular groove (5). The limiting protrusion (4) is rotatably disposed in the annular groove (5).

10. The device for controlling the over-pouring height of cast-in-place pile concrete according to claim 9, characterized in that: The annular groove (5) is provided with a fixing member (6), which is used to fix the limiting protrusion (4) when the outer tube ash inlet (21) and the inner tube ash inlet (11) are completely overlapped. The fixing member (6) includes a groove (61) on the side wall of the annular groove (5), a spring (62) and a positioning bead (63) in the groove (61). One end of the spring (62) is connected to the bottom wall of the groove (61), and the other end is connected to the positioning bead (63). The limiting protrusion (4) is provided with a fixing groove for the positioning bead (63) to slide into and be fixed.

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