Vibration sensor mounting device

Abstract

The utility model discloses a vibration sensor mounting device, and belongs to the technical field of road engineering stratum wave velocity testing and vibration monitoring. Comprising a plurality of sleeves buried in a plurality of soil layers, a mounting hole is formed in a set position of the wall of each sleeve, and a supporting piece is arranged at the bottom of each mounting hole; a reserved socket slot is fixedly welded on the inner wall of the sleeve on the opposite side of the mounting hole; a steel bar supporting device is arranged on the reserved socket groove and the supporting piece, and a vibration sensor is arranged between the steel bar supporting device and the supporting piece. And geotechnical cloth is arranged on the mounting holes. The sleeves can be arranged layer by layer, and the supporting sheets and the steel bar supporting devices are arranged in the sleeves, so that the vertical position of the vibration sensor is fixed, the vibration sensor is located at the set position of the current soil layer, and the test accuracy is ensured; steel bar supporting and separating rope recovery steel bar supporting devices are arranged at the two ends of the steel bar supporting device, and a sensor recovery rope recovery vibration sensor is arranged on the vibration sensor.

Description

Technical Field

[0001] This utility model belongs to the field of road engineering ground wave velocity testing and vibration monitoring technology, specifically relating to a vibration sensor installation device. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] During the construction of road subgrade and base course, the filling operation adopts a bottom-up, layered filling and compaction process. During the compaction of the layered soil layers by the road roller, the soil layers vibrate. Studies have shown a significant correlation between soil vibration characteristics and soil compaction degree. Current technology involves embedding vibration sensors throughout the entire filling layer's vibration field to continuously monitor the subgrade vibration response and predict soil compaction degree.

[0004] However, there are certain limitations to directly burying vibration sensors in the soil:

[0005] Because the construction adopts a layered filling and compaction method, the vibration sensor is directly buried in the soil layer. During the soil compaction process, if a heavy compactor is used, the vibration sensor will deviate from its position, and its vertical coordinate will also change. This cannot guarantee that the vibration sensor is located in the set position of the current soil layer, thus affecting the accuracy of the test. In addition, the vibration sensor cannot be recycled after the compaction operation because it is buried in layers of soil layer by layer, resulting in high monitoring costs. Utility Model Content

[0006] To address the aforementioned problems, this utility model provides a vibration sensor installation device. It employs a continuously extendable sleeve, installed layer by layer during the layered backfilling process. A support plate and a reinforcing steel support device are installed inside the sleeve to ensure the vertical position of the vibration sensor is fixed, preventing it from deviating due to external factors and ensuring the sensor remains at the designated position in the current soil layer, thus guaranteeing testing accuracy. By installing reinforcing steel support separation ropes at both ends of the reinforcing steel support device and pulling the connecting plate and damping plate upwards, the reinforcing steel support device can be pulled out of the sleeve. A sensor retrieval rope is installed on the vibration sensor; after the reinforcing steel support device loses its constraint on the vibration sensor, the sensor can be pulled out of the sleeve using the retrieval rope for recovery.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A vibration sensor installation device includes several sleeves buried in multiple soil layers. Each sleeve has an installation hole at a set position on its wall, and a support plate is provided at the bottom of the installation hole. On the opposite side of the installation hole, a reserved socket is fixedly welded to the inner wall of the sleeve.

[0009] A steel reinforcement support device is installed on the reserved socket and the support plate, and a vibration sensor is installed between the steel reinforcement support device and the support plate; geotextile is arranged on the mounting hole.

[0010] Preferably, the reserved slot includes a square steel pipe, with an equilateral angle steel welded to each end of the square steel pipe, and the equilateral angle steels are perpendicular to the square steel pipe; a receiving groove is formed between the two equilateral angle steels and the square steel pipe; the length of the square steel pipe is greater than the sum of the side lengths of the two equilateral angle steels, and an insertion opening is formed between the two equilateral angle steels.

[0011] Preferably, the steel bar support device includes multiple horizontal steel bars, with a connecting plate fixedly welded to one end of each horizontal steel bar.

[0012] Preferably, the connecting plate consists of a horizontal plate and a vertical plate, with the vertical plate fixedly connected to the center line of the short side of the horizontal plate; multiple horizontal steel bars are vertically fixedly welded to the center line of the short side of the vertical plate.

[0013] Preferably, the dimensions of each side of the connecting plate are a set length smaller than the dimensions of each side of the reserved slot.

[0014] Preferably, a damping plate is fixedly connected to the other end of the plurality of horizontal reinforcing bars. The damping plate includes a vertical damping plate perpendicular to the horizontal reinforcing bars, and a horizontal damping plate is vertically fixedly connected above the side of the vertical damping plate away from the horizontal reinforcing bars.

[0015] Preferably, steel reinforcement supports the separation ropes at the top of both the connecting plate and the damping plate.

[0016] Preferably, a sensor recovery rope is bonded and fixed to the top of each vibration sensor.

[0017] Preferably, one end of the support piece is fixedly connected to a hinge, and the other end of the hinge is fixed to the wall of the sleeve; a blocking iron block is welded to the bottom of the hinge's rotation shaft to prevent the support piece from swinging downwards and to keep it in a horizontal state.

[0018] Preferably, the upper end of the sleeve is provided with an upper bearing slot and the lower end is provided with a lower bearing groove, and the upper bearing slot and the lower bearing groove are matched and correspond; a limiting protrusion is provided on the upper bearing slot and a limiting groove is provided on the lower bearing groove, and the limiting protrusion and the limiting groove are matched and used.

[0019] Compared with the prior art, the advantages and positive effects of this utility model are:

[0020] This invention employs a continuously extendable sleeve, achieving depth extension through a socket connection. It allows for layer-by-layer installation during layered backfilling, facilitating convenient measurement of the vibration response properties of different soil layers. One end of the reinforcing steel support device is fixed to one side of the inner wall of the sleeve via a socket connection, while the other end, a damping plate, is supported by a support plate. The vibration sensor is placed between the support plate and the damping plate. When the soil outside the geotextile is squeezed into the sleeve, the horizontal displacement of the vibration sensor is restricted, ensuring the sensor adheres to the geotextile and maintains sufficient contact with the surrounding soil. This allows for monitoring of the vibration response properties of the current soil layer, improving the reliability of the monitoring data. Furthermore, the support plate and the reinforcing steel support device ensure the vertical position of the vibration sensor is fixed, placing it at the designated position within the current soil layer, thus guaranteeing test accuracy. By installing reinforcing steel support separation ropes at both ends of the reinforcing steel support device, the connecting plate and damping plate are pulled upwards, allowing the reinforcing steel support device to be pulled out of the sleeve. A sensor retrieval rope is installed on the vibration sensor. After the reinforcing steel support device loses its constraint on the vibration sensor, the sensor can be retrieved from the sleeve using the retrieval rope. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0022] Figure 1 This is a cross-sectional view of the vibration sensor installation device of this utility model arranged in the soil layer according to an embodiment of the present utility model.

[0023] Figure 2 This is a schematic diagram of the reserved support slot in an embodiment of the present utility model;

[0024] Figure 3 This is a schematic diagram of the sleeve connection according to an embodiment of the present utility model;

[0025] Figure 4 This is a schematic diagram of the support sheet according to an embodiment of the present utility model;

[0026] In the picture:

[0027] 1. First soil layer; 2. Horizontal reinforcement; 3. Second soil layer; 4. Reserved bearing slot; 5. Reinforcement support separation rope; 6. Sensor recovery rope; 7. Geotextile; 8. Vibration sensor; 9. Damping plate; 10. Support plate; 11. Sleeve; 12. Connecting plate; 13. Lower bearing groove; 14. Upper bearing slot; 15. Blocking iron block; 16. Hinge. Detailed Implementation

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] The present invention will now be described in detail with reference to the accompanying drawings. This embodiment discloses a vibration sensor mounting device, such as... Figure 1 As shown, it includes several hollow sleeves 11 of the same shape, size, and length buried in multiple soil layers from bottom to top. One sleeve 11 is buried in each soil layer, and the sleeves 11 in adjacent layers are connected; as shown Figure 1 As shown, the sleeves 11 buried between the first soil layer 1 and the second soil layer 3 are connected; each sleeve 11 has an installation hole at a set position on its pipe wall, and a horizontal support plate 10 is set at the bottom of the installation hole; on the opposite side of the installation hole, a reserved socket 4 is fixedly welded to the inner wall of the sleeve 11. In this embodiment, the sleeve 11 is a hollow steel pipe.

[0030] like Figure 1 As shown, the steel reinforcement support device and vibration sensor 8 are installed inside the sleeve 11 through the installation hole set at the designated position on the sleeve wall; the steel reinforcement support device is installed on the reserved socket 4 and the support plate 10, and the vibration sensor 8 is set between the steel reinforcement support device and the support plate 10 and fixed between the steel reinforcement support device and the support plate; geotextile 7 is arranged on the installation hole by pasting to seal the installation hole and prevent soil from entering the sleeve 11.

[0031] like Figure 1 As shown, in this embodiment, the vibration sensor 8 is located in the middle of the sleeve 11; in other embodiments, the vibration sensor 8 can also be installed at one-third or one-quarter of the distance from the ground on the sleeve 11; according to the set position, a reserved slot 4 is set in advance in the sleeve 11, and an installation hole is opened.

[0032] like Figure 1 As shown, a horizontal support plate 10 is provided at the bottom of the mounting hole, and a reserved slot 4 is fixedly welded to the inner wall of the middle section of the sleeve 11. The reserved slot 4 is set opposite to the mounting hole. The centroid of the reserved slot 4 and the centroid of the mounting hole are on the same horizontal plane and are symmetrical with respect to the axis of the sleeve 11.

[0033] It should be noted that, in this embodiment, the rebar support device is disposed between the support plate 10 and the reserved socket 4. The support plate 10 serves to support one side of the rebar support device; simultaneously, the support plate 10 is used to support the vibration sensor 8 and prevent the vibration sensor 8 from falling downwards. In this embodiment, the bottom of the mounting hole is located in the middle of the sleeve 11.

[0034] It should be noted that one side of the vibration sensor 8 is a steel reinforcement support device, and the other side is the geotextile 7 on the mounting hole, as well as the soil layer on the side of the geotextile 7 away from the sleeve 11. When the soil layer is compressed, the soil layer will squeeze the sleeve 11, which will in turn squeeze the vibration sensor 8 behind the geotextile 7. At this time, the function of the steel reinforcement support device is to prevent the vibration sensor 8 from moving horizontally away from the soil layer, thus preventing it from getting close to the soil layer and being unable to monitor the vibration response of the current soil layer.

[0035] It should also be explained that the installation hole facilitates the installation of the vibration sensor 8 and the steel reinforcement support device, and also avoids the direct installation of the vibration sensor 8 inside the sleeve, which would prevent the sleeve 11 from directly coupling the vibration sensor 8 with the soil, causing the vibration signal to attenuate or become distorted during transmission, ultimately affecting the accuracy of the measurement results.

[0036] like Figure 2 As shown, the reserved slot 4 includes a square steel pipe, with an equilateral angle steel welded to each end of the square steel pipe. The equilateral angle steels are perpendicular to the square steel pipe, and the two equilateral angle steels have the same specifications (same side width and same side thickness). Specifically, the square steel pipe is welded between the two sides of the equilateral angle steel, forming a receiving groove between the two equilateral angle steels and the square steel pipe. The length of the square steel pipe is greater than the sum of the side lengths of the two equilateral angle steels, thus forming an insertion opening between the two equilateral angle steels.

[0037] like Figure 2 As shown, the steel reinforcement support device includes multiple horizontal steel bars 2, with a connecting plate 12 fixedly welded to one end of each horizontal steel bar 2. The connecting plate 12 is T-shaped, consisting of a rectangular horizontal plate and a vertical plate. The vertical plate is fixedly connected to the center line of the short side of the horizontal plate, and the center line of the short side of the vertical plate coincides with the center line of the short side of the horizontal plate. The multiple horizontal steel bars 2 are vertically fixedly welded to the center line of the short side of the vertical plate.

[0038] In this embodiment, the connecting plate 12 can be made of steel, and the horizontal steel bar 2 is fixedly connected to the connecting plate 12 by welding.

[0039] It should be noted that the thickness, short side length, and long side length of the horizontal plate are slightly smaller than the thickness, short side length, and long side length of the receiving groove; the width (short side length) of the vertical plate is slightly smaller than the width (short side length) of the insertion opening; ensuring that the connecting plate can be slidably inserted into or pulled out of the reserved receiving slot 4; in this embodiment, the dimensions of each side of the connecting plate 12 are 3mm smaller than the dimensions of each side of the reserved receiving slot 4.

[0040] In this embodiment, two horizontal steel bars 2 are used. In some implementations, three or four steel bars can be used, as long as the rigidity of the steel bar support device can be guaranteed. No further requirements are made here.

[0041] It is easy to understand that by inserting the connecting plate 12 into the reserved socket 4, one end of the steel bar support device can be supported on the reserved socket 4.

[0042] like Figure 1 As shown, a damping plate 9 is fixedly connected to the other end of multiple horizontal reinforcing bars 2. The damping plate 9 is inverted L-shaped. Specifically, the damping plate 9 includes a vertical damping plate fixedly connected to the horizontal reinforcing bars, and a horizontal damping plate fixedly connected above the side of the vertical damping plate away from the horizontal reinforcing bars. The horizontal damping plate is perpendicular to the vertical damping plate. Figure 1 As shown, a vibration sensor 8 is installed between the vertical damping plate and the geotextile 7. The horizontal damping plate can prevent the vibration sensor 8 from running upward and forms a clamping effect on the vibration sensor 8.

[0043] The vertical position of the vibration sensor 8 is defined by the support plate 10 and the damping plate 9, thereby ensuring that the vibration sensor is located at the set position of the current soil layer.

[0044] In this embodiment, the damping plate 9 is made of polymer resin and composite material. In the prior art, polymer resin (such as polyurethane, epoxy resin, butyl rubber, etc.) has viscoelasticity. When subjected to vibration, the mutual friction and deformation energy of the molecular chains convert mechanical energy into heat energy, thereby achieving vibration reduction. By adding fillers (such as rubber particles, carbon fibers, clay) to the polymer resin, the interfacial friction and internal energy dissipation paths are enhanced, further improving the damping performance. The purpose of using the damping plate 9 is to reduce the influence of vibration on the vibration sensor 8 and improve the accuracy of the data measured by the vibration sensor 8.

[0045] It should be noted that since the damping plate 9 and the horizontal steel bar 2 are made of different materials, they cannot be fixed by welding. Instead, slots with the same number and position as the horizontal steel bar 2 can be made on the side of the vertical damping plate that faces away from the horizontal damping plate. The diameter of the slots is 5mm larger than the diameter of the horizontal steel bar 2. Adhesive is applied to the slots, and the horizontal steel bar 2 is inserted into the slots for bonding and fixing.

[0046] like Figure 1 As shown, reinforcing bar support separation ropes 5 are fixedly installed on the top of both the connecting plate 12 and the damping plate 9. These ropes are made of nylon and are tightly bound to both the connecting plate 12 and the damping plate 9. Specifically, corresponding nylon rope holes can be drilled on the top of the connecting plate 12 and the damping plate 9 to facilitate the passage and binding of the nylon ropes. Their function is that after the vibration sensor 8 completes monitoring, by pulling the reinforcing bar support separation ropes 5 on the top of the connecting plate 12 and the damping plate 9, the connecting plate 12 is pulled out of the reserved slot 4, thereby freeing the vibration sensor 8 from vertical and horizontal constraints, relieving the pressure on the vibration sensor 8, and creating conditions for the subsequent retrieval of the vibration sensor 8.

[0047] like Figure 1 As shown, each of the multiple vibration sensors 8 has a sensor recovery rope 6 fixed to its top. The sensor recovery rope 6 is also made of nylon and is connected to the vibration sensor by binding. In this embodiment, the vibration sensor model used can be: YZHBA5, a general-purpose housing vibration sensor. The sensor recovery rope 6 is wrapped tightly around the housing of the vibration sensor. After the steel bar support device is retrieved, the sensor recovery rope 6 is pulled upwards to remove the multiple vibration sensors 8 from the sleeve 11, completing the retrieval.

[0048] like Figure 1 , Figure 3 As shown, the support piece 10 is connected to the wall of the sleeve 11 below the mounting hole by a hinge. Specifically, a hinge 16 can be fixedly connected to one end of the support piece 10, and the other end of the hinge 16 can be fixed to the wall of the sleeve 11. To prevent the support piece 10 from swinging downwards excessively, a blocking iron block 15 is welded and fixed to the bottom of the rotation axis of the hinge 16 on the inner wall of the sleeve 11, so that the support piece 10 no longer swings downwards and remains in a horizontal state.

[0049] The reason for hinged connection between the support plate 10 and the sleeve 11, making it movable, is that when the rebar support device is being retrieved, the rebar support device in the lower sleeve 11 touches the upper support plate 10, and the support plate 10 can rotate upwards, ensuring that the rebar support device in the lower sleeve 11 can be smoothly removed.

[0050] like Figure 1 , Figure 3 As shown, the upper end of the sleeve 11 is provided with an upper bearing slot 14, and the lower end is provided with a lower bearing groove 13. The upper bearing slot 14 and the lower bearing groove 13 are matched and correspond. The outer diameter of the upper bearing slot 14 is equal to the inner diameter of the lower bearing groove 13, the inner diameter of the upper bearing slot is equal to the inner diameter of the sleeve 11, and the outer diameter of the lower bearing groove is equal to the outer diameter of the sleeve 11. The sleeves 11 are connected to each other through the upper bearing slot and the lower bearing groove.

[0051] In some embodiments, vertical limiting protrusions and limiting grooves can also be provided on the upper bearing slot and the lower bearing groove. For example, symmetrical vertical limiting protrusions can be provided on the upper bearing slot and symmetrical vertical limiting grooves can be provided on the lower bearing groove, with the limiting protrusions and limiting grooves used in a matching manner; when the upper bearing slot is inserted into the lower bearing groove, the limiting protrusions are inserted into the limiting grooves, which can limit the relative rotation between the sleeves 11; thereby enabling all mounting holes to face one side, so that all vibration sensors 8 can face one side for monitoring.

[0052] It is important to note that, such as Figure 1 As shown, the upper bearing slot of the sleeve 11 in the current soil layer needs to protrude from the current soil layer, that is, the length of the sleeve 11 in the current soil layer is equal to the thickness of the current soil layer plus the length of the upper bearing slot.

[0053] Installation process:

[0054] In this embodiment, when filling the first soil layer 1, the sleeve 11 is vertically placed into the soil layer, the soil near the installation hole is excavated to expose the installation hole, the steel reinforcement support device is placed into the sleeve 11 through the installation hole, the connecting plate 12 is aligned with the reserved socket 4 and inserted, and then the steel reinforcement support separation rope 5 is pulled out of the sleeve 11.

[0055] At this time, the damping plate 9 is located above the support plate 10. The vibration sensor 8 is placed between the support plate 10 and the damping plate 9. Then, the sensor recovery rope 6 is pulled out of the sleeve 11, and geotextile is placed at the installation hole. Finally, soil is filled at the installation hole.

[0056] After completing the above steps, the upper bearing slot of the sleeve 11 exposes the first soil layer 1, and then the current soil layer is compacted.

[0057] When filling the second soil layer 3, the next sleeve 11 is connected to the sleeve 11 in the first soil layer 1 through the upper bearing slot and the lower bearing groove, and the above steps of installing the vibration sensor 8 are repeated; then the second soil layer 3 is compacted.

[0058] Repeat the above steps until all soil layers have been compacted.

[0059] After confirming that the monitoring task is completed, first lift the steel bar support device of the steel bar support separation rope 5 upward as a whole to release the pressure of the steel bar support device on the vibration sensor, so that the vibration sensor is no longer under force and stays on the support plate. Then pull the sensor recovery rope 6 on the vibration sensor to pull the vibration sensor out of the sleeve 11 as a whole.

[0060] This invention employs a continuously extendable sleeve 11, which achieves depth extension through a socket connection. This allows for layer-by-layer installation during layered backfilling, facilitating convenient measurement of the vibration response properties of different soil layers. Compared to traditional fixed sensors, it can be flexibly assembled according to actual testing needs, adapting to soil layer testing at different depths. In this invention, one end of the steel reinforcement support device is fixed to one side of the inner wall of the sleeve via a socket connection, while the other end is supported by a damping plate. The vibration sensor is placed between the support plate and the damping plate. When the soil outside the geotextile is squeezed into the sleeve, the horizontal displacement of the vibration sensor is restricted, ensuring the sensor adheres to the geotextile and maintains full contact with the surrounding soil. This allows for monitoring of the vibration response properties of the current soil layer, improving the reliability of the monitoring data.

[0061] This utility model provides a steel bar support separation rope at both ends of the steel bar support device. During retrieval, it is only necessary to pull the connecting plate and damping plate of the steel bar support device as a whole to pull the steel bar support device out of the sleeve 11. A sensor retrieval rope is provided on the vibration sensor. After the steel bar support device loses its constraint on the vibration sensor, the vibration sensor can be pulled out of the sleeve through the sensor retrieval rope to complete the retrieval.

[0062] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A vibration sensor mounting device, characterized in that, It includes several sleeves buried in multiple soil layers. Each sleeve has an installation hole at a set position on its wall, and a support plate is set at the bottom of the installation hole. On the opposite side of the installation hole, a pre-reserved socket is fixedly welded to the inner wall of the sleeve. A steel reinforcement support device is installed on the reserved socket and the support plate, and a vibration sensor is installed between the steel reinforcement support device and the support plate; geotextile is arranged on the mounting hole.

2. The vibration sensor mounting device as described in claim 1, characterized in that, The reserved slot includes a square steel pipe, with an equilateral angle steel welded to each end of the square steel pipe, both of which are perpendicular to the square steel pipe; a receiving groove is formed between the two equilateral angle steels and the square steel pipe; the length of the square steel pipe is greater than the sum of the side lengths of the two equilateral angle steels, forming an insertion opening between the two equilateral angle steels.

3. The vibration sensor mounting device as described in claim 1, characterized in that, The steel reinforcement support device includes multiple horizontal steel bars, with a connecting plate fixedly welded to one end of each horizontal steel bar.

4. The vibration sensor mounting device as described in claim 3, characterized in that, The connecting plate consists of a horizontal plate and a vertical plate, with the vertical plate fixedly connected to the center line of the short side of the horizontal plate; multiple horizontal steel bars are vertically fixed and welded to the center line of the short side of the vertical plate.

5. The vibration sensor mounting device as described in claim 3, characterized in that, The dimensions of each side of the connecting plate are set to be smaller than the dimensions of each side of the reserved slot.

6. The vibration sensor mounting device as described in claim 3, characterized in that, The other end of the plurality of horizontal reinforcing bars is fixedly connected to a damping plate, the damping plate including a vertical damping plate perpendicular to the horizontal reinforcing bars, and a horizontal damping plate is vertically fixedly connected above the side of the vertical damping plate away from the horizontal reinforcing bars.

7. The vibration sensor mounting device as described in claim 6, characterized in that, Reinforcing bars are fixedly installed on the top of both the connecting plate and the damping plate to support the separation rope.

8. The vibration sensor mounting device as described in claim 1, characterized in that, Each vibration sensor has a sensor retrieval rope tied to its top.

9. A vibration sensor mounting device as described in claim 1, characterized in that, One end of the support piece is fixedly connected to a hinge, and the other end of the hinge is fixed to the wall of the sleeve. A blocking iron block is welded to the bottom of the hinge's rotation axis to prevent the support piece from swinging downwards and keep it in a horizontal state.

10. A vibration sensor mounting device as described in claim 1, characterized in that, The upper end of the sleeve is provided with an upper bearing slot, and the lower end is provided with a lower bearing groove. The upper bearing slot and the lower bearing groove are matched and correspond to each other. A limiting protrusion is provided on the upper bearing slot, and a limiting groove is provided on the lower bearing groove. The limiting protrusion and the limiting groove are matched and used.

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