Automatic floating and sinking seabed static detection equipment

Abstract

The invention relates to the technical field of static detection equipment, and discloses automatic floating and sinking seabed static detection equipment, which comprises a pontoon and a frame body, a pulling structure is arranged on the pontoon, a driving structure is arranged in the frame body, and the driving structure drives a sounding rod to longitudinally move, so that the sounding rod downwards penetrates into a seabed layer or is upwards lifted to be separated from the seabed layer; a connector is arranged on the frame body in a protruding mode, the connector is connected with a rotationally-arranged buoy, an annular cavity is formed in the buoy, and the pulling structure is connected with the connector. A plurality of longitudinal through holes are formed in the buoy, and the diameters of the longitudinal holes are gradually reduced; by injecting water into the annular cavity or injecting gas into the annular cavity and discharging the water, the buoy can automatically float and sink in seawater, so that the frame body sinks on the seabed, or the frame body floats from the seabed; in the automatic floating and sinking process of the buoy, seawater can penetrate through the longitudinal hole and the buoy, the transverse arrangement state of the whole buoy is kept, and the stability of the buoy and the frame body is kept.

Description

Technical Field

[0001] This invention patent relates to the technical field of static exploration equipment, specifically to an automatic floating and sinking submarine static exploration equipment. Background Art

[0002] The investigation and research of the properties of submarine soil are an essential and important part of marine engineering construction such as offshore oil platforms, submarine tunnels, oil and gas pipelines, and optical cables. The research on the properties of sediments within several to dozens of meters below the seabed is of great significance for various aspects such as marine environmental investigation, submarine resource exploration, and marine development and utilization.

[0003] Currently, generally, submarine static exploration equipment is used to conduct in-situ exploration of submarine sediments, including a frame body, on which a driving structure and a sounding rod are provided. After the frame body sinks and is placed on the sediments, the driving structure is used to drive the sounding rod to penetrate into the sediments, and sensors are used to measure the force data during the penetration process, etc.

[0004] In the prior art, during the exploration process, the frame body needs to be lifted or sunk. Generally, a lifting structure is used to lift the frame body, and the self-weight of the frame body is used for sinking. It is impossible to achieve the automatic floating and sinking of the frame body, resulting in low operation efficiency and being time-consuming and laborious. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic floating and sinking submarine static exploration equipment, aiming to solve the problem that the submarine static exploration equipment in the prior art cannot achieve automatic floating and sinking.

[0006] The present invention is implemented as follows. The automatic floating and sinking submarine static exploration equipment includes a floating ship swimming in seawater and a frame body placed in seawater. A pulling structure is provided on the floating ship, and the pulling structure is connected to the frame body; the frame body is arranged in a hollow shape, a driving structure is provided in the frame body, the driving structure is connected to a sounding rod, and the driving structure drives the sounding rod to move longitudinally so that the sounding rod penetrates into the seabed layer or is lifted out of the seabed layer.

[0007] A connecting head protrudes from the frame body, and a rotatably arranged floating cylinder is connected to the connecting head. The floating cylinder is arranged around the circumference of the connecting head. The interior of the floating cylinder has an annular cavity that can be filled with water or gas. The annular cavity is arranged around the circumference of the connecting head, and the pulling structure is connected to the connecting head.

[0008] A plurality of longitudinally penetrating longitudinal holes are provided in the floating cylinder. The plurality of longitudinal holes are arranged at intervals around the circumference of the floating cylinder; the top of the floating cylinder has a top ring surface, the bottom of the floating cylinder has a bottom ring surface, the longitudinal holes penetrate the top ring surface to form top openings, the longitudinal holes penetrate the bottom ring surface to form bottom openings, and along the direction from the bottom opening to the top opening, the diameter of the longitudinal holes gradually decreases.

[0009] Furthermore, the pulling structure includes a retractor and a cable. The cable is connected to the retractor and the connector respectively. By retracting or relaxing the cable with the retractor, the frame moves upward or downward.

[0010] Furthermore, a plurality of elastic bands are connected to the cable. The plurality of elastic bands are arranged around the circumference of the buoy. The upper ends of the plurality of elastic bands are gathered and connected to the cable, and the lower ends of the plurality of elastic bands are spaced and connected to the buoy.

[0011] When the buoy drives the frame to float and the cable is in a pulled state, the elastic bands are in a stretched state. When the frame is placed on the seabed and the cable is in a relaxed state, the elastic bands are in a relaxed state.

[0012] Furthermore, the driving structure includes two rollers arranged side by side. The outer circumference of the roller has a circumferential portion. The circumferential portions of the two rollers are arranged facing each other with a gap therebetween, forming a rolling gap for the sounding rod to pass through.

[0013] The sounding rod is inserted into the rolling gap and abuts against the circumferential portion. The two rollers rotate synchronously and in opposite directions to drive the sounding rod to move up and down.

[0014] Furthermore, a lower positioning head is provided on the frame. The lower positioning head is located below the rolling gap, and the sounding rod passes through the lower positioning head. A longitudinally arranged guide rail is provided on the frame. The lower positioning head is movably connected to the guide rail. When the sounding rod moves up and down, the lower positioning head moves up and down along the guide rail.

[0015] Furthermore, an upper positioning head is provided above the rolling gap. The upper positioning head includes two positioning clips. The middle part of the positioning clip is curved, enclosing a curved area. The curved areas of the two positioning clips are arranged facing each other and are vertically offset from each other. The sounding rod is movably inserted between the two positioning clips and is movably embedded in the curved area.

[0016] Furthermore, the curved area has a curved side wall, and an elastic layer is covered on the curved side wall. The elastic layer abuts against the outer circumference of the sounding rod.

[0017] Furthermore, a plurality of elastically swinging downwardly one-way elastic pieces are provided in the middle of the longitudinal hole. The plurality of elastic pieces are arranged around the circumference of the longitudinal hole. The outer ends of the elastic pieces are butted against the inner side wall of the longitudinal hole, and the inner ends of the elastic pieces extend towards the middle of the longitudinal hole.

[0018] When the buoy sinks in seawater, multiple elastic sheets are arranged horizontally to close the longitudinal holes; when the buoy floats in seawater, multiple elastic sheets elastically deform downward, the longitudinal holes are opened, and the seawater passes through the longitudinal holes.

[0019] Furthermore, the bottom annular surface is arranged horizontally, and multiple groove rings are provided on the bottom annular surface. The multiple groove rings are nested at intervals along the radial direction of the bottom annular surface and are arranged in a circumferential manner around the bottom annular surface; a suspension ring is rotatably arranged in the groove ring, and the suspension ring is arranged in a circumferential manner around the groove ring;

[0020] The upper part of the suspension ring is movably placed in the groove ring to form an upper ring, and the lower part of the suspension ring extends to the bottom of the groove ring to form a flat lower ring.

[0021] Furthermore, along the direction from the middle to both sides of the lower ring, both sides of the lower ring are bent upward, and multiple notches are respectively provided on both sides of the lower ring. The multiple notches are arranged at intervals along the circumferential direction of the lower ring.

[0022] Compared with the prior art, the automatic floating and sinking seabed static detection device provided by the present invention can realize the automatic floating and sinking of the buoy in seawater by injecting water or injecting gas and discharging water into the annular cavity, so that the frame body sinks on the seabed or the frame body floats up from the seabed; the pulling structure and the floating ship can pull the suspended frame body to a set position. When the frame body sinks to the seabed layer, the driving structure can drive the sounding rod into the seabed or lift the sounding rod out of the seabed;

[0023] The buoy is provided with multiple longitudinal holes, which are arranged in a circumferential manner around the buoy. During the process of automatic floating and sinking of the buoy, seawater can pass through the longitudinal holes and penetrate through the buoy, so as to maintain the horizontal arrangement state of the entire buoy, avoid the phenomenon of the buoy capsizing or excessive longitudinal swing, and maintain the stability of the buoy and the frame body. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the front view schematic diagram of the automatic floating and sinking seabed static detection device provided by the present invention;

[0025] Figure 2 is the front view schematic diagram of the cooperation between the sounding rod and the roller provided by the present invention;

[0026] Figure 3 is the sectional view schematic diagram of the cooperation between the upper positioning head and the sounding rod provided by the present invention;

[0027] Figure 4 is the internal schematic diagram of the cooperation between the suspension ring and the groove ring provided by the present invention

[0028] Figure 5It is an internal schematic diagram of the longitudinal hole provided by the present invention in a closed state;

[0029] Figure 6 It is an internal schematic diagram of the longitudinal hole provided by the present invention in an open state. Specific embodiments

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0032] In the drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be understood as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0033] Refer to Figures 1-6 As shown, it is a preferred embodiment provided by the present invention.

[0034] An automatic floating and sinking seabed static detection device includes a floating ship swimming in seawater and a frame 100 placed in seawater. A pulling structure is provided on the floating ship, and the pulling structure is connected to the frame 100; the frame 100 is arranged in a hollow shape, and a driving structure is provided in the frame 100. The driving structure is connected with a sounding rod 101, and the driving structure drives the sounding rod 101 to move longitudinally so that the sounding rod 101 penetrates into the seabed layer or is lifted out of the seabed layer.

[0035] A connecting head 200 protrudes upward from the frame 100, and a rotatably arranged floating cylinder 300 is connected to the connecting head 200. The floating cylinder 300 is arranged around the circumference of the connecting head 200. The inside of the floating cylinder 300 has an annular cavity into which water or gas can be injected. The annular cavity is arranged around the circumference of the connecting head 200, and the pulling structure is connected to the connecting head 200.

[0036] When the frame 100 needs to sink in seawater, water can be injected into the annular cavity. The buoyancy of the buoy 300 is less than the gravity, and the frame 100 and the buoy 300 sink in seawater together. When the frame 100 needs to float in seawater, gas can be injected into the annular cavity, and at the same time, the water in the annular cavity is discharged. The buoyancy of the buoy 300 is greater than the gravity, so that the frame 100 floats automatically synchronously with the buoy 300.

[0037] A plurality of longitudinally penetrating longitudinal holes 304 are provided in the buoy 300, and the plurality of longitudinal holes 304 are arranged at intervals around the circumference of the buoy 300. The top of the buoy 300 has a top ring surface, and the bottom of the buoy 300 has a bottom ring surface 305. The longitudinal holes 304 penetrate the top ring surface to form a top opening 301, and the longitudinal holes 304 penetrate the bottom ring surface 305 to form a bottom opening 302. Along the direction from the bottom opening 302 to the top opening 301, the diameter of the longitudinal holes 304 gradually decreases.

[0038] The above-provided automatic floating and sinking seabed static detection device can realize the automatic floating and sinking of the buoy 300 in seawater by injecting water or injecting gas and discharging water into the annular cavity, so that the frame 100 sinks on the seabed or the frame 100 floats from the seabed; the pulling structure and the floating ship can pull the suspended frame 100 to a set position. When the frame 100 sinks to the seabed, the driving structure can drive the sounding rod 101 into the seabed or lift the sounding rod 101 out of the seabed.

[0039] The buoy 300 is provided with a plurality of longitudinal holes 304, which are arranged around the circumference of the buoy 300. During the process of automatic floating and sinking of the buoy 300, seawater can pass through the longitudinal holes 304 and penetrate through the buoy 300, so as to maintain the horizontal arrangement state of the entire buoy 300, avoid the phenomenon of the buoy 300 tipping over or swinging longitudinally too much, and maintain the stability of the buoy 300 and the frame 100.

[0040] In this embodiment, the pulling structure includes a winch and a cable 202. The cable 202 is connected to the winch and the connector 200 respectively. By winding or relaxing the cable 202 with the winch, the frame 100 moves up or down. When the buoy 300 and the frame 100 float synchronously, the buoy 300 can also be pulled up by using the cable 202 to accelerate the floating speed of the buoy 300.

[0041] Or, when the buoy 300 and the frame 100 are suspended synchronously in seawater, the cable 202 and the floating ship can be used to pull the buoy 300 and the frame 100 to move in seawater, so that the frame 100 moves to a set position.

[0042] In this embodiment, a plurality of elastic bands 201 are connected to the cable 202. The plurality of elastic bands 201 are arranged in a circumferential direction around the buoy 300. The upper ends of the plurality of elastic bands 201 are converged and connected to the cable 202, and the lower ends of the plurality of elastic bands 201 are spaced apart and connected to the buoy 300.

[0043] When the buoy 300 drives the frame 100 to float and the cable 202 is in a pulling state, the elastic band 201 is in a stretched state. When the frame 100 is placed on the seabed and the cable 202 is in a relaxed state, the elastic band 201 is in a relaxed state.

[0044] In this way, when the cable 202 pulls or guides the buoy 300 to float, the elastic band 201 is in a stretched state. Moreover, the lower ends of the plurality of elastic bands 201 are connected to the buoy 300 and arranged in a circumferential direction around the buoy 300, which can achieve stable upward pulling and guiding of the buoy 300, avoid excessive longitudinal swing of the buoy 300, and keep the buoy 300 floating smoothly.

[0045] In this embodiment, the driving structure includes two rollers 400 arranged side by side. The outer periphery of the roller 400 has a circumferential portion 401. The circumferential portions 401 of the two rollers 400 are arranged facing each other at intervals, forming a rolling interval for the sounding rod 101 to pass through. The sounding rod 101 is inserted into the rolling interval and abuts against the circumferential portion 401. The two rollers 400 rotate synchronously and in opposite directions to drive the sounding rod 101 to move up and down.

[0046] By pressing the sounding rod 101 with the two rollers 400 and rotating the two rollers 400 synchronously and in opposite directions, the sounding rod 101 is driven to move up and down. The circumferential portion 401 can be provided with a circumferential groove, which is arranged in a circumferential direction along the circumferential portion 401. In this way, it is convenient for the sounding rod 101 to be embedded in the circumferential groove, and the rotation of the roller 400 can better press against the longitudinal movement of the sounding rod 101.

[0047] In this embodiment, a lower positioning head 402 is provided on the frame 100. The lower positioning head 402 is located below the rolling interval, and the sounding rod 101 passes through the lower positioning head 402. A longitudinally arranged guide rail 403 is provided on the frame 100. The lower positioning head 402 is movably connected to the guide rail 403. When the sounding rod 101 moves up and down, the lower positioning head 402 moves up and down along the guide rail 403.

[0048] By arranging the lower positioning head 402, the longitudinal movement of the sounding rod 101 can be positioned and guided. Moreover, when the sounding rod 101 moves longitudinally, the lower positioning head 402 synchronously moves longitudinally along the guide rail 403, avoiding interference with the movement of the sounding rod 101 and guiding the movement of the sounding rod 101 better.

[0049] In this embodiment, an upper positioning head 404 is provided above the rolling interval. The upper positioning head 404 includes two positioning clips 4041. The middle part of the positioning clip 4041 is curved, enclosing a curved area. The curved areas of the two positioning clips 4041 are arranged facing each other and are vertically offset along the longitudinal direction. The sounding rod 101 movably passes through between the two positioning clips 4041 and is movably embedded in the curved area.

[0050] By arranging the upper positioning head 404, the longitudinal movement of the sounding rod 101 can be guided and positioned. Cooperating with the lower positioning head 402, upper and lower guiding and positioning can be synchronously achieved above and below the rolling interval.

[0051] Secondly, the two positioning clips 4041 are vertically offset along the longitudinal direction, so that the two positioning clips 4041 can clamp the sounding rod 101 vertically and offset, playing a role in vertically offset guiding and positioning for the longitudinal movement of the sounding rod 101, so that during the longitudinal movement of the sounding rod 101, the fluctuation of the set angle is satisfied, ensuring that the sounding rod 101 can move longitudinally more smoothly.

[0052] In this embodiment, the curved area has a curved side wall, and an elastic layer 4042 is covered on the curved side wall. The elastic layer 4042 abuts against the outer periphery of the sounding rod 101. In this way, during the longitudinal movement of the sounding rod 101, the elastic layer 4042 can be elastically compressed and deformed appropriately to satisfy the fluctuation of the set angle of the sounding rod 101.

[0053] In this embodiment, a plurality of elastic pieces 303 that swing downward unidirectionally are provided in the middle of the longitudinal hole 304. The plurality of elastic pieces 303 are arranged in a circumferential manner around the longitudinal hole 304. The outer ends of the elastic pieces 303 are butted against the inner side wall of the longitudinal hole 304, and the inner ends of the elastic pieces 303 extend toward the middle of the longitudinal hole 304;

[0054] When the floating cylinder 300 sinks in seawater, the plurality of elastic pieces 303 are arranged horizontally to close the longitudinal hole 304; when the floating cylinder 300 floats in seawater, the plurality of elastic pieces 303 elastically deform downward, and the longitudinal hole 304 is opened, and seawater passes through the longitudinal hole 304.

[0055] In this way, when the floating cylinder 300 and the frame 100 sink in seawater, the longitudinal hole 304 is closed, and the floating cylinder 300 sinks as a whole, which can maintain the sinking stability of the floating cylinder 300 and the frame 100; when the floating cylinder 300 and the frame 100 float in seawater, the longitudinal hole 304 is opened, and seawater can pass through the longitudinal hole 304, so as to make the floating cylinder 300 float smoothly and avoid the floating cylinder 300 from capsizing or having too large longitudinal swing during the floating process.

[0056] In this embodiment, the bottom toroidal surface 305 is arranged horizontally. A plurality of groove rings 306 are provided on the bottom toroidal surface 305. The plurality of groove rings 306 are nested at intervals along the radial direction of the bottom toroidal surface 305 and are arranged in a circumferential arrangement along the bottom toroidal surface 305. The groove ring 306 is provided with a floating ring arranged to rotate. The floating ring is arranged in a circumferential arrangement along the groove ring 306.

[0057] The upper part of the floating ring is movably placed in the groove ring 306 to form an upper ring 307, and the lower part of the floating ring extends to the bottom of the groove ring 306 to form a lower ring 308 in the shape of a flat plate. By arranging the floating ring on the bottom toroidal surface 305 and the floating ring can rotate around the groove ring 306, during the process of the buoy 300 floating up or sinking, the buoy 300 can maintain its stability through the autonomous floating rotation of the floating ring.

[0058] In this embodiment, along the direction from the middle to both sides of the lower ring 308, both sides of the lower ring 308 are bent upward, and a plurality of notches 309 are respectively provided on both sides of the lower ring 308. The plurality of notches 309 are arranged at intervals along the circumferential direction of the lower ring 308. The upward bending of the lower ring 308 can maintain the stability of the lower ring 308 in seawater, and both sides of the lower ring 308 have notches 309, which is convenient for seawater to drive the lower ring 308 to rotate, so that the floating ring automatically rotates in the groove ring 306.

[0059] When the buoy 300 has a longitudinal swing, the floating ring automatically rotates in the groove ring 306 according to the swing change of the buoy 300, thereby playing a role in adjusting the longitudinal swing of the buoy 300 and avoiding excessive longitudinal swing of the buoy 300.

[0060] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An automatic floating and sinking seabed static detection device, characterized in that, It includes a floating ship moving in seawater and a frame placed in seawater. A pulling structure is provided on the floating ship, and the pulling structure is connected to the frame. The frame is arranged in a hollow shape, and a driving structure is provided in the frame. The driving structure is connected with a sounding rod, and the driving structure drives the sounding rod to move longitudinally so that the sounding rod penetrates into the seabed or is lifted out of the seabed. A connecting head protrudes upward from the frame, and a rotatably arranged floating cylinder is connected to the connecting head. The floating cylinder is arranged around the circumference of the connecting head. An annular cavity for injecting water or gas is provided inside the floating cylinder, and the annular cavity is arranged around the circumference of the connecting head. The pulling structure is connected to the connecting head. A plurality of longitudinally penetrating longitudinal holes are provided in the floating cylinder, and the plurality of longitudinal holes are arranged at intervals around the circumference of the floating cylinder. The top of the floating cylinder has a top ring surface, and the bottom of the floating cylinder has a bottom ring surface. The longitudinal holes penetrate the top ring surface to form top openings, and the longitudinal holes penetrate the bottom ring surface to form bottom openings. Along the direction from the bottom opening to the top opening, the diameter of the longitudinal holes gradually decreases.

2. The automatic floating and sinking seabed static detection device according to claim 1, characterized in that, The pulling structure includes a winch and a cable. The cable is connected to the winch and the connecting head respectively. By winding or relaxing the cable with the winch, the frame moves upward or downward.

3. The automatic floating and sinking seabed static detection device according to claim 2, wherein A plurality of elastic bands are connected to the cable, and the plurality of elastic bands are arranged around the circumference of the floating cylinder. The upper ends of the plurality of elastic bands converge and are connected to the cable, and the lower ends of the plurality of elastic bands are connected to the floating cylinder at intervals. When the floating cylinder drives the frame to float and the cable is in a pulled state, the elastic bands are in a stretched state. When the frame is placed on the seabed and the cable is in a relaxed state, the elastic bands are in a relaxed state.

4. The automatic floating and sinking seabed static detection device according to any one of claims 1 to 3, characterized in that, The driving structure includes two rollers arranged side by side. The outer circumference of the roller has a circumferential part. The circumferential parts of the two rollers are arranged facing each other at intervals to form a rolling interval for the sounding rod to pass through. The sounding rod is arranged in the rolling interval and abuts against the circumferential part. The two rollers rotate synchronously and in opposite directions to drive the sounding rod to move up and down.

5. The automatic floating and sinking seabed static detection device according to claim 4, characterized in that, A lower positioning head is provided on the frame. The lower positioning head is located below the rolling interval, and the sounding rod passes through the lower positioning head. A longitudinally arranged guide rail is provided on the frame, and the lower positioning head is movably connected to the guide rail. When the sounding rod moves up and down, the lower positioning head moves up and down along the guide rail.

6. The automatic floating and sinking seabed static detection device according to claim 5, characterized in that, An upper positioning head is provided above the rolling interval. The upper positioning head includes two positioning clips. The middle part of the positioning clip is bent to form a bent area. The bent areas of the two positioning clips are arranged facing each other and are longitudinally offset up and down. The sounding rod movably passes through between the two positioning clips and is movably embedded in the bent area.

7. The automatic floating and sinking seabed static detection device according to claim 6, characterized in that, The bent area has a bent side wall, and an elastic layer is covered on the bent side wall. The elastic layer abuts against the outer circumference of the sounding rod.

8. The automatic floating and sinking seabed static detection device according to any one of claims 1 to 3, characterized in that, A plurality of elastic sheets that swing unidirectionally downward are provided in the middle of the longitudinal hole. The plurality of elastic sheets are arranged in a circumferential direction around the longitudinal hole. The outer ends of the elastic sheets are butt-jointed to the inner side wall of the longitudinal hole, and the inner ends of the elastic sheets extend toward the middle of the longitudinal hole. When the buoy sinks in seawater, the plurality of elastic sheets are arranged horizontally to close the longitudinal hole; when the buoy floats in seawater, the plurality of elastic sheets elastically deform downward, the longitudinal hole opens, and the seawater passes through the longitudinal hole.

9. The automatic floating and sinking seabed static detection device according to any one of claims 1 to 3, characterized in that, The bottom annular surface is arranged horizontally, and a plurality of groove rings are provided on the bottom annular surface. The plurality of groove rings are nested at intervals along the radial direction of the bottom annular surface and are arranged in a circumferential direction around the bottom annular surface; a floating ring arranged to rotate is provided in the groove ring, and the floating ring is arranged in a circumferential direction around the groove ring. The upper part of the floating ring is movably placed in the groove ring to form an upper ring, and the lower part of the floating ring extends to the bottom of the groove ring to form a lower ring in a flat plate shape.

10. The automatic floating and sinking seabed static detection device according to claim 9, characterized in that, Along the direction from the middle to both sides of the lower ring, both sides of the lower ring are bent upward, and a plurality of notches are respectively provided on both sides of the lower ring. The plurality of notches are arranged at intervals along the circumferential direction of the lower ring.

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