A grouting device suitable for geotechnical engineering

Abstract

This invention relates to the field of grouting technology in geotechnical engineering, and more particularly to a grouting device suitable for geotechnical engineering. The invention includes a frame, a reinforcing frame, a support plate, an anti-detachment arc-shaped plate, and a grouting tank. Two reinforcing frames and one support plate are fixed to both ends of the top of the frame. Through the structural design of the grouting mechanism and the positioning mechanism, this invention enables the device to rapidly grout areas with grouting ports. Simultaneously, it can position the injection pipe during the grouting process, preventing the end of the injection pipe from being thrown out of the grouting port when loosening occurs between the injection pipe and the grouting pipe, thus maintaining the stability of the injection pipe and improving the safety of the device. Furthermore, through the structural design of the material removal mechanism, after grouting is completed, the device can separate the injection pipe from the grouting pipe and vibrate the material inside the injection pipe, causing the material to fall out from the inside of the injection pipe, preventing the material from solidifying inside the injection pipe, which is beneficial for use.

Description

Technical Field

[0001] This invention relates to the field of grouting technology in geotechnical engineering, and more particularly to a grouting device suitable for geotechnical engineering. Background Technology

[0002] When geotechnical engineering projects face complex situations such as fractured geological zones, soft rock, prone to rockfall and spalling, landslide instability, large deformation, risks of water seepage or inrush, and piping, grouting reinforcement is a commonly used treatment method. By injecting grout into the rock mass, the grout's bonding and solidification mechanisms reinforce the surrounding rock, significantly improving the effectiveness of support and water blocking. This reinforcement process typically requires specialized grouting equipment.

[0003] For example, a geotechnical engineering grouting device with publication number CN113668537A relates to the field of geotechnical engineering grouting technology. It includes a base, a mixing box, a mixing device, a speed control component, a feeding device, and a grouting device. The mixing box is located on one side of the base and connected to the base via a fixing rod. A square plate is connected to the fixing rod. A discharge port is provided on one side of the mixing box for unloading the grout. The mixing device is located inside the mixing box for mixing the grout. The speed control component is located on one side of the mixing box for controlling the flow rate of the grout. The feeding device is located at the end of the mixing box away from the horizontal plate for conveying raw materials. The grouting device is located inside the base for grouting.

[0004] In summary, the following technical problems exist in the existing technology: Although the existing technology can realize the grouting process, the injection pipe is subjected to high pressure to transport raw materials. If the injection pipe becomes loose or falls off during the grouting process, a tailing phenomenon is likely to occur, making the process of transporting raw materials unstable. Therefore, we propose a grouting device suitable for geotechnical engineering. Summary of the Invention

[0005] The purpose of this invention is to provide a grouting device suitable for geotechnical engineering, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A grouting device suitable for geotechnical engineering includes a frame, a reinforcing frame, a support plate, an anti-detachment arc plate, and a grouting tank. Two reinforcing frames and one support plate are fixed at both ends of the top of the frame. An anti-detachment arc plate is fixed to the top of each support plate. A grouting tank is fixed between the two anti-detachment arc plates. A reinforcing plate is fixed to the outside of the grouting tank. The reinforcing plate is fixed to the top of the reinforcing frame. A grouting mechanism is assembled on one side of the grouting tank.

[0008] Preferably, the grouting mechanism includes a delivery pump, a connecting pipe, an injection pipe, and a connector. The delivery pump is fixed to one side of the grouting tank, the input end of the delivery pump is fixed to the connecting pipe, one end of the connecting pipe is fixed to the grouting tank, the output end of the delivery pump is fixed to the injection pipe, and the bottom of the injection pipe is rotatably sealed to the connector.

[0009] Preferably, a positioning mechanism is installed on the inner side of the frame, which is used to position the injection tube.

[0010] Preferably, in the positioning mechanism, a mounting plate is fixed to one end of the inner side of the frame, a transmission component is assembled on one side of the mounting plate, and a guide component is assembled on the inner side of the transmission component.

[0011] Preferably, the transmission assembly includes a first motor, a worm gear, a horizontal plate, and a vertical cylinder. Two first motors are fixed on one side of the mounting plate, and a worm gear is fixed to the output end of each first motor. A horizontal plate is fixed on one side of the mounting plate, offset from the position of the first motors, and a vertical cylinder is fixed to one end of the horizontal plate.

[0012] Preferably, the guide assembly includes a positioning ring, a bearing block, an adjusting cylinder, a long rod, and a movable block. The two ends of the outer side of the vertical cylinder are rotatably connected to the positioning ring. One side of the positioning ring is engaged with a worm gear. Multiple bearing blocks are evenly distributed and fixed to the top of the positioning ring. An adjusting cylinder is fixed to one side of each bearing block. Multiple movable blocks are evenly distributed and rotatably connected to the top of the vertical cylinder. A long rod is slidably connected to the inner side of each adjusting cylinder. One end of the long rod is fixed to a movable block.

[0013] Preferably, a bearing plate is fixed between the two support plates, and a material release mechanism is assembled on the top of the bearing plate.

[0014] Preferably, the unloading mechanism includes a rectangular shell, a second motor, a rotating rod, a rectangular cavity, a cam, a circular ring, a force-applying rod, an extension block, a T-shaped cylinder, and auxiliary components. The top of the bearing plate is fixed to the rectangular shell, the top of the rectangular shell is fixed to the second motor, the rotating rod is rotatably connected to the inner side of the rectangular shell, the output end of the second motor is fixed to the rotating rod, a rectangular cavity is opened at one end of the rectangular shell, a cam is fixed to the bottom of the rotating rod, a circular ring is rotatably connected to the protrusion of the cam, a force-applying rod is fixed to one side of the circular ring, an extension block is fixed to one end of the force-applying rod, a T-shaped cylinder is rotatably connected to the top and bottom of the extension block, the T-shaped cylinder is slidably connected to the reinforcing frame, and auxiliary components are assembled between the T-shaped cylinder and the reinforcing frame.

[0015] Preferably, the auxiliary component includes an anti-detachment support rod, a damping head, a first spring, a partition, an extension cylinder, and a second spring. One end of the T-shaped cylinder is slidably connected to the anti-detachment support rod, and one end of the anti-detachment support rod is fixed to the damping head. The damping head corresponds to the position of the injection pipe and is slidably connected to the reinforcement frame. The other end of the anti-detachment support rod, located inside the T-shaped cylinder, is fitted with the first spring. One end of the first spring is fixed to the T-shaped cylinder, and the other end of the first spring is fixed to the partition. The inner side of the partition is fixed to the anti-detachment support rod. The side of the damping head closest to the reinforcement frame is fixed to the second spring. The side of the reinforcement frame closest to the second spring is integrally fixed to the extension cylinder, and one end of the second spring is fixed to one end of the inner side of the extension cylinder.

[0016] It is clear without a doubt that the technical solution described above in this application can solve the technical problem that this application aims to address.

[0017] Meanwhile, through the above technical solutions, the present invention has at least the following beneficial effects:

[0018] 1. Through the structural design of the grouting mechanism and the positioning mechanism, this invention enables the device to quickly grout areas with grouting ports. At the same time, it can position the injection pipe during the grouting process. When the injection pipe and the grouting pipe become loose, it prevents the end of the injection pipe from being thrown out of the grouting port, so that the injection pipe can still maintain a stable state, thus improving the safety of the device.

[0019] 2. Through the structural design of the material removal mechanism, this invention enables the device to separate the injection pipe from the grouting pipe after grouting is completed, and then vibrate the raw material inside the injection pipe, causing the raw material to fall out from the inside of the injection pipe, thus preventing the raw material from solidifying inside the injection pipe, which is beneficial for use. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the connection structure between the delivery pump and the grouting tank of the present invention;

[0023] Figure 3 This is a schematic diagram of the connection structure between the frame and the mounting plate of the present invention;

[0024] Figure 4This is a schematic diagram of the connection structure between the vertical cylinder and the positioning ring of the present invention;

[0025] Figure 5 This is a schematic diagram of the connection structure between the rectangular shell and the second motor of the present invention;

[0026] Figure 6 This is a cross-sectional view of the rectangular shell of the present invention.

[0027] The attached diagram lists the components represented by each number as follows:

[0028] In the diagram: 1. Frame; 2. Reinforcing frame; 3. Support plate; 4. Anti-detachment arc plate; 5. Grouting tank; 6. Reinforcing plate; 7. Conveying pump; 8. Connecting pipe; 9. Injection pipe; 10. Connecting joint; 11. Mounting plate; 12. First motor; 13. Worm gear; 14. Horizontal plate; 15. Vertical cylinder; 16. Positioning ring; 17. Bearing block; 18. Adjusting cylinder; 19. Long rod; 20. Movable block; 21. Bearing layer plate; 22. Rectangular shell; 23. Second motor; 24. Rotating rod; 25. Rectangular cavity; 26. Cam; 27. Circular ring; 28. Force rod; 29. ​​Extension circular block; 30. T-shaped cylinder; 31. Anti-detachment support rod; 32. Vibration damping head; 33. First spring; 34. Partition plate; 35. Extension cylinder; 36. Second spring. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 merely illustrative and not intended to limit the invention.

[0030] Example 1

[0031] Reference Figures 1-4 A grouting device suitable for geotechnical engineering includes a frame 1, a reinforcing frame 2, a support plate 3, an anti-detachment arc plate 4, and a grouting tank 5. Two reinforcing frames 2 and a support plate 3 are fixed at both ends of the top of the frame 1. An anti-detachment arc plate 4 is fixed at the top of each support plate 3. A grouting tank 5 is fixed between the two anti-detachment arc plates 4. A reinforcing plate 6 is fixed to the outside of the grouting tank 5. The reinforcing plate 6 is fixed to the top of the reinforcing frame 2. A grouting mechanism is assembled on one side of the grouting tank 5.

[0032] The grouting mechanism includes a conveying pump 7, a connecting pipe 8, an injection pipe 9, and a connector 10. The conveying pump 7 is fixed to one side of the grouting tank 5. The input end of the conveying pump 7 is fixed to the connecting pipe 8, and one end of the connecting pipe 8 is fixed to the grouting tank 5. The output end of the conveying pump 7 is fixed to the injection pipe 9. The bottom of the injection pipe 9 is rotatably sealed to the connector 10. When the conveying pump 7 is started, the conveying pump 7 transfers the raw material in the grouting tank 5 to the injection pipe 9 through the connecting pipe 8, and finally discharges it into the corresponding grouting hole through the injection pipe 9 and the grouting pipe.

[0033] A positioning mechanism is installed on the inner side of the frame 1 to position the injection tube 9. The positioning mechanism includes a transmission component and a guide component. A mounting plate 11 is fixed to one end of the inner side of the frame 1. A transmission component is installed on one side of the mounting plate 11, and a guide component is installed on the inner side of the transmission component. The transmission component includes a first motor 12, a worm gear 13, a horizontal plate 14, and a vertical cylinder 15. Two first motors 12 are fixed to one side of the mounting plate 11, and the output end of each first motor 12 is fixed with a worm gear 13. A horizontal plate 14 is fixed to one side of the mounting plate 11, offset from the first motors 12. A vertical cylinder 15 is fixed to one end of the horizontal plate 14. When the first motor 12 is started, the output end of the first motor 12 drives the worm gear 13 to rotate, thereby causing the worm gear 13 to mesh with the positioning ring 16 and rotate.

[0034] The guide assembly includes a positioning ring 16, a bearing block 17, an adjusting cylinder 18, a long rod 19, and a movable block 20. The two ends of the outer side of the vertical cylinder 15 are rotatably connected to the positioning ring 16. One side of the positioning ring 16 is engaged with the worm gear 13. Multiple bearing blocks 17 are evenly distributed and fixed on the top of the positioning ring 16. An adjusting cylinder 18 is fixed on one side of each bearing block 17. Multiple movable blocks 20 are evenly distributed and rotatably connected to the top of the vertical cylinder 15. Long rods 19 are slidably connected to the inner side of the adjusting cylinder 18. One end of the long rod 19 is fixed to the movable block 20. The adjusting cylinder 18 has a cavity to accommodate the retraction of the long rod 19. At the same time, the outer side of the adjusting cylinder 18 is provided with anti-slip texture to increase the friction between the adjusting cylinder 18 and the injection pipe 9.

[0035] Example 2

[0036] Further optimizations to Example 1, specifically, such as... Figure 1 , Figure 5 and Figure 6As shown, a bearing plate 21 is fixed between the two support plates 3, and a material ejection mechanism is assembled on the top of the bearing plate 21. The material ejection mechanism includes a rectangular shell 22, a second motor 23, a rotating rod 24, a rectangular cavity 25, a cam 26, a circular ring 27, a force-applying rod 28, an extension block 29, a T-shaped cylinder 30, and auxiliary components. The rectangular shell 22 is fixed on the top of the bearing plate 21, and the second motor 23 is fixed on the top of the rectangular shell 22. The rotating rod 24 is rotatably connected to the inner side of the rectangular shell 22. The output end of the second motor 23 is fixed to the rotating rod 24. A rectangular cavity 25 is opened at one end of the rectangular shell 22. A cam 26 is fixed to the bottom of the rotating rod 24. A circular ring 27 is rotatably connected to the protrusion of the cam 26. A force-applying rod 28 is fixed to one side of the circular ring 27. An extension block 29 is fixed to one end of the force-applying rod 29. The top and bottom of the extension block 29 are rotatably connected to a T-shaped cylinder 30. The T-shaped cylinder 30 is slidably connected to the reinforcing frame 2. An auxiliary component is assembled between the T-shaped cylinder 30 and the reinforcing frame 2. When the second motor 23 is started, the output end of the second motor 23 drives the rotating rod 24 to rotate, so that the cam 26 drives the circular ring 27 to perform cam motion, so that the circular ring 27 continuously pushes or pulls the force application rod 28 and the extension block 29, thereby causing the T-shaped cylinder 30 to pull or squeeze the first spring 33 to deform, realizing the uneven lateral movement of the damping head 32, so that the damping head 32 continuously contacts the injection pipe 9 to generate impact force, causing the raw material in the injection pipe 9 to fall out.

[0037] The auxiliary components include an anti-detachment support rod 31, a damping head 32, a first spring 33, a partition 34, an extension cylinder 35, and a second spring 36. The anti-detachment support rod 31 is slidably connected to one end of the T-shaped cylinder 30, and the damping head 32 is fixed to one end of the anti-detachment support rod 31. The damping head 32 corresponds to the position of the injection pipe 9 and is slidably connected to the reinforcement frame 2. The first spring 33 is sleeved on the other end of the anti-detachment support rod 31, located inside the T-shaped cylinder 30. One end of the first spring 33 is fixed to the T-shaped cylinder 30, and the other end... A partition 34 is fixed, and the inner side of the partition 34 is fixed to the anti-detachment support rod 31. A second spring 36 is fixed on the side of the damping head 32 near the reinforcing frame 2. An extension tube 35 is integrally fixed on the side of the reinforcing frame 2 near the second spring 36. One end of the second spring 36 is fixed to one end of the inner side of the extension tube 35. A buffer pad is provided on the side of the damping head 32 near the injection tube 9, which can provide buffer protection when the damping head 32 vibrates the injection tube 9, so that the raw material in the injection tube 9 can fall out, and the injection tube 9 can be prevented from being damaged.

[0038] In summary:

[0039] This invention addresses the technical problem of existing technologies, which, while capable of grouting, suffer from instability in material delivery due to the high pressure applied to the grouting pipe. If the grouting pipe becomes loose or detaches during grouting, a tailing phenomenon can occur, making the material delivery process unstable. The invention employs the technical solutions described in the above embodiments. Furthermore, the implementation process of the above technical solutions is as follows:

[0040] During use, the bottom of the injection pipe 9 passes through the inner side of the bearing plate 21 and the inner side of the vertical cylinder 15. The injection pipe 9 is connected to the grouting pipe through the connector 10. Then, the first motor 12 is started, causing the output end of the first motor 12 to drive the worm gear 13 to rotate. Because the worm gear 13 is engaged with the positioning ring 16, and the positioning ring 16 is rotatably connected to the vertical cylinder 15, the worm gear 13 can engage the positioning ring 16 to rotate. Since the positioning ring 16 is fixed to the bearing block 17, the adjusting cylinder 18 is slidably connected to the long rod 19, the long rod 19 is fixed to the movable block 20, and the movable block 20 is slidably connected to the vertical cylinder 15, the worm gear 13 can engage the positioning ring 16 to rotate. The cylinder 15 is rotatably connected, so that during the rotation of the bearing block 17 driven by the positioning ring 16, one end of the long rod 19 retracts towards the inside of the adjusting cylinder 18, thereby causing multiple adjusting cylinders 18 to continuously converge towards the center of the vertical cylinder 15. This allows multiple adjusting cylinders 18 to fix the injection pipe 9 in multiple directions, facilitating stable positioning of the injection pipe 9 and increasing the stable connection between the injection pipe 9 and the grouting pipe. The conveying pump 7 is started, and the raw materials in the grouting tank 5 are transferred to the injection pipe 9 through the connecting pipe 8, and finally discharged into the corresponding grouting hole through the injection pipe 9 and the grouting pipe.

[0041] With the above-mentioned settings, this application will certainly solve the above-mentioned technical problems, and at the same time achieve the following technical effects:

[0042] 1. Through the structural design of the grouting mechanism and the positioning mechanism, this invention enables the device to quickly grout areas with grouting ports. At the same time, it can position the injection pipe 9 during the grouting process. When the injection pipe 9 becomes loose from the grouting pipe, it prevents the end of the injection pipe 9 from being thrown out of the grouting port, so that the injection pipe 9 can still maintain a stable state, thus improving the safety of the device.

[0043] 2. Through the structural design of the material removal mechanism, this invention enables the device to separate the injection pipe 9 from the grouting pipe after grouting is completed, and then vibrate the raw material inside the injection pipe 9, so that the raw material falls out of the injection pipe 9, avoiding the raw material from solidifying inside the injection pipe 9, which is beneficial to use.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A grouting device suitable for geotechnical engineering, characterized in that, The machine includes a frame (1), a reinforcing frame (2), a support plate (3), an anti-detachment arc plate (4), and a grouting tank (5). Two reinforcing frames (2) and a support plate (3) are fixed at both ends of the top of the frame (1). An anti-detachment arc plate (4) is fixed at the top of each support plate (3). A grouting tank (5) is fixed between the two anti-detachment arc plates (4). A reinforcing plate (6) is fixed on the outside of the grouting tank (5). The reinforcing plate (6) is fixed to the top of the reinforcing frame (2). A grouting mechanism is assembled on one side of the grouting tank (5).

2. The grouting device for geotechnical engineering according to claim 1, characterized in that, The grouting mechanism includes a delivery pump (7), a connecting pipe (8), an injection pipe (9), and a connector (10). The delivery pump (7) is fixed on one side of the grouting tank (5). The input end of the delivery pump (7) is fixed with the connecting pipe (8). One end of the connecting pipe (8) is fixed to the grouting tank (5). The output end of the delivery pump (7) is fixed with the injection pipe (9). The bottom of the injection pipe (9) is rotatably sealed with the connector (10).

3. A grouting device suitable for geotechnical engineering according to claim 2, characterized in that, The frame (1) is equipped with a positioning mechanism on its inner side, which is used to position the injection tube (9).

4. A grouting device suitable for geotechnical engineering according to claim 3, characterized in that, The positioning mechanism has a transmission assembly and a guide assembly. One end of the frame (1) is fixed with a mounting plate (11). A transmission assembly is mounted on one side of the mounting plate (11), and a guide assembly is mounted on the inner side of the transmission assembly.

5. A grouting device suitable for geotechnical engineering according to claim 4, characterized in that, The transmission assembly includes a first motor (12), a worm gear (13), a horizontal plate (14), and a vertical cylinder (15). Two first motors (12) are fixed on one side of the mounting plate (11), and a worm gear (13) is fixed to the output end of each of the first motors (12). A horizontal plate (14) is fixed on one side of the mounting plate (11) and at a position away from the first motors (12). A vertical cylinder (15) is fixed to one end of the horizontal plate (14).

6. A grouting device suitable for geotechnical engineering according to claim 5, characterized in that, The guide assembly includes a positioning ring (16), a bearing block (17), an adjusting cylinder (18), a long rod (19), and a movable block (20). The two ends of the outer side of the vertical cylinder (15) are rotatably connected to the positioning ring (16). One side of the positioning ring (16) is engaged with the worm gear (13). Multiple bearing blocks (17) are evenly distributed and fixed on the top of the positioning ring (16). An adjusting cylinder (18) is fixed on one side of each bearing block (17). Multiple movable blocks (20) are evenly distributed and rotatably connected on the top of the vertical cylinder (15). A long rod (19) is slidably connected to the inner side of the adjusting cylinder (18). One end of the long rod (19) is fixed to the movable block (20).

7. A grouting device suitable for geotechnical engineering according to claim 2, characterized in that, A bearing plate (21) is fixed between the two support plates (3), and a material release mechanism is assembled on the top of the bearing plate (21).

8. A grouting device suitable for geotechnical engineering according to claim 7, characterized in that, The unloading mechanism includes a rectangular shell (22), a second motor (23), a rotating rod (24), a rectangular cavity (25), a cam (26), a circular ring (27), a force-applying rod (28), an extension block (29), a T-shaped cylinder (30), and auxiliary components. The top of the bearing plate (21) is fixed with a rectangular shell (22), and the top of the rectangular shell (22) is fixed with a second motor (23). The rotating rod (24) is rotatably connected to the inner side of the rectangular shell (22). The output end of the second motor (23) is fixed to the rotating rod (24). The rectangular shell (26) is rotatably connected to the rotating rod (24). 2) One end is provided with a rectangular cavity (25), the bottom of the rotating rod (24) is fixed with a cam (26), the protrusion of the cam (26) is rotatably connected with a circular ring (27), one side of the circular ring (27) is fixed with a force rod (28), one end of the force rod (28) is fixed with an extension block (29), the top and bottom of the extension block (29) are rotatably connected with a T-shaped cylinder (30), the T-shaped cylinder (30) is slidably connected with the reinforcing frame (2), and an auxiliary component is assembled between the T-shaped cylinder (30) and the reinforcing frame (2).

9. A grouting device suitable for geotechnical engineering according to claim 8, characterized in that, The auxiliary components include an anti-detachment support rod (31), a damping head (32), a first spring (33), a partition (34), an extension cylinder (35), and a second spring (36). The anti-detachment support rod (31) is slidably connected to one end of the T-shaped cylinder (30), and the damping head (32) is fixed to one end of the anti-detachment support rod (31). The damping head (32) corresponds to the position of the injection pipe (9), and the damping head (32) is slidably connected to the reinforcement frame (2). The other end of the anti-detachment support rod (31) is located inside the T-shaped cylinder (30). A first spring (33) is sleeved on the first spring (33), one end of the first spring (33) is fixed to the T-shaped cylinder (30), and the other end of the first spring (33) is fixed to a partition (34). The inner side of the partition (34) is fixed to the anti-detachment support rod (31). A second spring (36) is fixed on the side of the damping head (32) near the reinforcing frame (2). An extension tube (35) is integrally fixed on the side of the reinforcing frame (2) near the second spring (36). One end of the second spring (36) is fixed to one end of the inner side of the extension tube (35).

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