Overturn-preventing heavy-load suspension special for track

Abstract

The invention discloses a special anti-overturning heavy-load suspension for a track, and relates to the technical field of track suspensions, the special anti-overturning heavy-load suspension comprises a support and a truss, rotating frames are symmetrically arranged on the two sides of the truss, transmission shafts are arranged in the rotating frames, track wheels are arranged on the two sides of the transmission shafts, and a damping assembly is arranged on the top of the truss. A vehicle plate is arranged on the side, away from the truss, of the damping assembly and used for containing a cargo compartment, and supporting assemblies are symmetrically arranged on the two sides of the support. The gravity of the cargo compartment also acts on the surface of the supporting assembly, the supporting assembly immediately moves towards the side away from the cargo compartment and is matched with the rail wheels to support the cargo compartment, and therefore the bearing capacity of the support is improved, and by arranging the supporting assembly, distribution of the weight of the cargo compartment and the cargo is achieved. And the risk of overturning of the cargo compartment in the operation process is avoided, and then the stability of cargo transportation is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of track suspensions, in particular to a special anti-overturning heavy-load suspension for tracks. Background Art

[0002] Railway freight cars, passenger cars, and EMU vehicles mainly use primary and secondary suspensions. Primary suspension is a suspension device installed between the bogie frame and the wheelset. Its main function is to reduce the vibration caused by unsprung mass and track irregularities. This type of suspension usually uses rubber or steel springs as axle box suspension devices, which can effectively isolate high-frequency vibrations from the wheels and rails and improve the smoothness of vehicle operation. Secondary suspension is a suspension device installed between the bogie frame and the car body. It consists of steel springs, vertical and lateral shock absorbers, and stops. However, when railway freight cars are heavily loaded, the track suspension bears enormous pressure, which is transmitted to the track wheels through the suspension. This may cause deformation in the middle of the suspension, thereby affecting the center of gravity and making it easy for the train to overturn at curves on the railway. Summary of the Invention

[0003] The object of the present invention is to provide a track-specific anti-overturning heavy-load suspension to solve the problems raised in the prior art.

[0004] To achieve the above object, the present invention provides the following technical solutions: A rail-specific anti-overturning heavy-load suspension comprises a bracket, with traveling frames symmetrically arranged at the front and rear ends of the bracket, rotating frames symmetrically arranged on both sides of the traveling frame, a transmission shaft arranged inside the rotating frame, track wheels arranged on both sides of the transmission shaft, a shock-absorbing assembly arranged on the top of the traveling frame, a vehicle plate arranged on the side of the shock-absorbing assembly away from the traveling frame, the vehicle plate being used for placing a cargo compartment, and support assemblies symmetrically arranged on both sides of the bracket.

[0005] The cargo compartment is placed on the vehicle bed, and the cargo is placed in the cargo compartment. Then, the cargo compartment and the cargo in the cargo compartment press the shock-absorbing assembly under the action of gravity, so that the shock-absorbing assembly moves under the action of the cargo compartment and the cargo. The shock-absorbing assembly moves to the side close to the bracket. During the movement of the shock-absorbing assembly, the gravity of the cargo compartment also acts on the surface of the support assembly. The support assembly then moves to the side away from the cargo compartment and cooperates with the rail wheels to support the cargo compartment, thereby increasing the bearing capacity of the bracket. By setting the support assembly, the weight of the cargo compartment and the cargo is distributed, avoiding the risk of the cargo compartment overturning during operation, thereby ensuring the stability of cargo transportation.

[0006] Preferably, the shock absorbing assembly consists of two groups of shock absorbing springs and a support plate. The two groups of shock absorbing springs are symmetrically arranged above the two ends of the traveling frame, and the support plate is arranged on the side of the shock absorbing spring away from the traveling frame.

[0007] The cargo compartment and cargo are placed on the surface of the vehicle plate, and then under the influence of gravity, the vehicle plate moves to the side close to the support plate. The support plate then presses the shock-absorbing spring, causing the shock-absorbing spring to contract under pressure. In the process of cargo transportation, the shock-absorbing spring always pushes the cargo in the opposite direction, avoiding vibration during transportation and causing damage to the cargo.

[0008] Preferably, a rotating groove is provided in the middle of the bracket, a rotating shaft is provided in the rotating groove, the rotating shaft is rotatably connected to the rotating groove, a fixed block is provided on the rotating shaft, a movable groove is provided on the side of the vehicle plate close to the rotating groove, the fixed block extends into the movable groove, and the fixed block is slidably connected to the movable groove.

[0009] While the vehicle plate is pressing the support plate, the vehicle plate drives the movable groove to move, and the movable groove moves toward the side close to the fixed block, so that the fixed block moves toward the depth of the movable groove. Then, when transporting through corners, the bracket produces a certain deflection, and then the bracket drives the rotating groove to rotate. Since the rotating shaft is rotatably connected to the rotating groove, and the cargo compartment can always be in a vertical state with the horizontal plane under the influence of gravity, the vehicle plate drives the movable groove to rotate, and when the movable groove rotates, it drives the fixed block to rotate, and the fixed block drives the rotating shaft to rotate, so that the rotating shaft deflects around the axis of the rotating groove, thereby ensuring the stability of the cargo compartment during transport through corners.

[0010] Preferably, the support assembly includes an extension block, which is arranged on one side of the bracket. A sliding cavity is arranged inside the extension block, and the sliding cavity consists of a vertical groove and two limiting grooves. The vertical groove is arranged in the center of the sliding cavity, and the limiting grooves are symmetrically arranged on both sides of the vertical groove.

[0011] When there is no cargo compartment and cargo, the push plate is at the top of the stroke, and the sliding column is at the top of the vertical slot. The first hinged plate is retracted in the limit slot. At the same time, the first support wheel is rollingly connected to the track surface, and the second support wheel and the third support wheel are both in a state of being out of track. At this time, when the suspension moves on the track, the resistance generated is small, which reduces energy consumption.

[0012] Preferably, a sliding column is provided in the vertical groove, and the sliding column is slidably connected to the vertical groove. A first hinge plate is provided on both sides of the sliding column, and a push rod is provided in the middle of the sliding column. The push rod extends out of the sliding cavity, and a push plate is provided on the side of the push rod away from the vertical groove. The upper surface of the push plate is in the same plane as the upper surface of the vehicle plate, and a plurality of support springs are provided on the side of the push plate close to the extension block.

[0013] When the cargo box acts on the surface of the vehicle plate, since the upper surface of the push plate is in the same plane as the upper surface of the vehicle plate, part of the side of the cargo box acts on the surface of the push plate, and then the cargo box and the cargo also exert a pressing force on the push plate, thereby pushing the plate to move toward the side close to the vertical groove. When the push plate moves, the push rod moves, so that the push rod continuously extends into the sliding cavity; When the push rod moves, it drives the sliding column to move, and the sliding column moves vertically along the vertical groove. When the sliding column moves, it drives the first hinge plates arranged on both sides to move. The first hinge plates move along the limiting grooves, so that the first hinge plates move away from the side of the sliding column to the side close to the track wheel.

[0014] Preferably, a second hinge plate is provided on a side of the first hinge plate away from the sliding column, the first hinge plate is hinged to the second hinge plate, and the second hinge plate is provided with a first support wheel, a second support wheel and a third support wheel.

[0015] The first hinge plate drives the second hinge plate to rotate during its movement, and the second hinge plate rotates from the side away from the first support wheel to the side close to the track wheel. The second hinge plate drives the second support wheel and the third support wheel to rotate during its rotation; When the sliding column moves to the bottom of the vertical slot, the sliding column is at its farthest stroke, the second hinge plate is parallel to the track, and the first support wheel, the second support wheel and the third support wheel are in contact with the track surface and are rollingly connected to the track.

[0016] Preferably, a first support wheel is provided at the hinge of the two second hinged plates, the first support wheel is hinged to the second hinged plate, a third support wheel is provided at the hinge of the first hinged plate and the second hinged plate, a second support wheel is provided between the first support wheel and the third support wheel, and the first support wheel and the third support wheel are rotatably connected to the second hinged plate.

[0017] The gravity of the cargo compartment and the cargo changes, causing the distance the cargo compartment presses the push plate to move to different distances, thereby changing the angle between the second hinged plate and the track, thereby changing whether the second support wheel and the third support wheel are in contact with the track; When the cargo compartment is in a heavily loaded state, the second hinged plate is parallel to the track, and the first support wheel, the second support wheel and the third support wheel are in contact with the track surface and provide support force to the cargo compartment, thereby increasing the load capacity of the cargo compartment and dispersing the gravity of the cargo compartment; When the cargo compartment is moderately loaded, the second hinged plate and the track are at an angle of less than 30°, and at this time only the first support wheel and the second support wheel are in contact with the track surface, so that the first support wheel and the second support wheel increase the supporting force of the cargo compartment, thereby increasing the carrying capacity while reducing the energy consumption generated by the same cargo.

[0018] Preferably, the diameter of the first support wheel is the same as the diameter of the third support wheel, and the diameter of the second support wheel is larger than the diameters of the first support wheel and the third support wheel.

[0019] Preferably, an extrusion groove is provided on the side of the second hinged plate close to the second support wheel, an extrusion ring is provided in the extrusion groove, the extrusion ring is slidingly connected to the extrusion groove, the second support wheel is rotatably connected to the extrusion ring, and an extrusion spring is symmetrically provided on the side of the extrusion ring close to the extrusion groove.

[0020] Since the diameter of the first support wheel is the same as that of the third support wheel, and the diameter of the second support wheel is larger than that of the first support wheel and the third support wheel, the second support wheel preferentially contacts the track surface during the rotation of the second hinge plate. As the second hinge plate continues to rotate, the second support wheel drives the extrusion ring to move, and the extrusion ring moves along the extrusion groove, so that the extrusion ring squeezes the extrusion spring, so that the contact point between the second support wheel and the track is in the same plane as the contact points between the first support wheel and the third support wheel and the track.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. When the cargo compartment is in a heavily loaded state, the second hinged plate is parallel to the track, and the first, second and third support wheels are in contact with the track surface and provide support force to the cargo compartment, thereby increasing the load capacity of the cargo compartment and dispersing the gravity of the cargo compartment.

[0022] 2. When the cargo compartment is moderately loaded, the second hinged plate and the track are at an angle of less than 30°. At this time, only the first support wheel and the second support wheel are in contact with the track surface, so that the first support wheel and the second support wheel increase the supporting force of the cargo compartment, thereby increasing the carrying capacity while reducing the energy consumption generated by the same cargo.

[0023] 3. When there is no cargo compartment and cargo, the push plate is at the top of the stroke, and the sliding column is at the top of the vertical slot. The first hinged plate is retracted in the limit slot. At the same time, the first support wheel is rollingly connected to the track surface, and the second support wheel and the third support wheel are both in a state of being out of track. At this time, when the suspension moves on the track, the resistance generated is small, reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the present invention when no cargo is loaded; Figure 2 It is a side view of the present invention when not loaded with cargo; Figure 3 This is a schematic diagram of the structure of the present invention when heavily loaded; Figure 4 This is a side view of the present invention when heavily loaded; Figure 5 Schematic diagram of the bottom structure of the present invention; Figure 6 It is a front view of the present invention; Figure 7 This is a schematic diagram of the internal structure of the support assembly when it is not loaded with cargo; Figure 8 This is a schematic diagram of the internal structure of the support assembly when it is heavily loaded; Figure 9 for Figure 7 Enlarged view of point A in the middle; In the figure: 1, bracket; 11, carriage; 12, rotating frame; 13, transmission shaft; 14, track wheel; 15, rotating groove; 16, rotating shaft; 17, fixed block; 2. Shock-absorbing assembly; 21. Shock-absorbing spring; 22. Support plate; 3. Car plate; 31. Moving trough; 4. Support assembly; 41. Extension block; 42. Sliding cavity; 43. Vertical slot; 431. Sliding column; 44. Limiting slot; 45. First hinge plate; 46. Push rod; 47. Push plate; 48. Second hinge plate; 49. First support wheel; 50. Second support wheel; 51. Third support wheel; 52. Extrusion slot; 53. Extrusion ring. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Example: Figures 1-9 As shown, the present invention provides a technical solution for a track-specific anti-overturning heavy-load suspension. A track-specific anti-overturning heavy-load suspension includes a bracket 1, with a traveling frame 11 symmetrically provided at the front and rear ends of the bracket 1, a rotating frame 12 symmetrically provided on both sides of the traveling frame 11, a transmission shaft 13 provided in the rotating frame 12, and track wheels 14 provided on both sides of the transmission shaft 13, a shock absorbing assembly 2 provided on the top of the traveling frame 11, a vehicle plate 3 provided on the side of the shock absorbing assembly 2 away from the traveling frame 11, and the vehicle plate 3 is used to place the cargo compartment, and support assemblies 4 are symmetrically provided on both sides of the bracket 1.

[0027] As a specific embodiment of the present invention, the shock absorbing assembly 2 is composed of two groups of shock absorbing springs 21 and a support plate 22. The two groups of shock absorbing springs 21 are symmetrically arranged above the two ends of the traveling frame 11, and the support plate 22 is arranged on the side of the shock absorbing springs 21 away from the traveling frame 11.

[0028] As a specific embodiment of the present invention, a rotating groove 15 is provided in the middle of the bracket 1, a rotating shaft 16 is provided in the rotating groove 15, the rotating shaft 16 is rotatably connected to the rotating groove 15, a fixed block 17 is provided on the rotating shaft 16, and a movable groove 31 is provided on the side of the vehicle plate 3 close to the rotating groove 15, the fixed block 17 extends into the movable groove 31, and the fixed block 17 is slidably connected to the movable groove 31.

[0029] As a specific embodiment of the present invention, the support assembly 4 includes an extension block 41, which is arranged on one side of the bracket 1. A sliding cavity 42 is arranged inside the extension block 41. The sliding cavity 42 consists of a vertical groove 43 and two limiting grooves 44. The vertical groove 43 is arranged in the center of the sliding cavity 42, and the limiting grooves 44 are symmetrically arranged on both sides of the vertical groove 43.

[0030] As a specific embodiment of the present invention, a sliding column 431 is provided in the vertical groove 43, and the sliding column 431 is slidably connected to the vertical groove 43. A first hinge plate 45 is provided on both sides of the sliding column 431, and a push rod 46 is provided in the middle of the sliding column 431. The push rod 46 extends out of the sliding cavity 42, and a push plate 47 is provided on the side of the push rod 46 away from the vertical groove 43. The upper surface of the push plate 47 is in the same plane as the upper surface of the vehicle plate 3, and a plurality of support springs are provided on the side of the push plate 47 close to the extension block 41.

[0031] As a specific embodiment of the present invention, a second hinge plate 48 is provided on the side of the first hinge plate 45 away from the sliding column 431, the first hinge plate 45 is hinged to the second hinge plate 48, and the second hinge plate 48 is provided with a first support wheel 49, a second support wheel 50 and a third support wheel 51.

[0032] As a specific embodiment of the present invention, a first support wheel 49 is provided at the hinge of the two second hinged plates 48, and the first support wheel 49 is hinged to the second hinged plate 48. A third support wheel 51 is provided at the hinge of the first hinged plate 45 and the second hinged plate 48, and a second support wheel 50 is provided between the first support wheel 49 and the third support wheel 51. The first support wheel 49 and the third support wheel 51 are rotatably connected to the second hinged plate 48.

[0033] As a specific embodiment of the present invention, the diameter of the first support wheel 49 is the same as the diameter of the third support wheel 51 , and the diameter of the second support wheel 50 is larger than the diameters of the first support wheel 49 and the third support wheel 51 .

[0034] As a specific embodiment of the present invention, an extrusion groove 52 is provided on the side of the second hinged plate 48 close to the second support wheel 50, and an extrusion ring 53 is provided in the extrusion groove 52. The extrusion ring 53 is slidingly connected to the extrusion groove 52, and the second support wheel 50 is rotatably connected to the extrusion ring 53. The extrusion ring 53 is symmetrically provided with an extrusion spring on the side close to the extrusion groove 52.

[0035] Working principle of the present invention: The cargo compartment and the cargo are placed on the surface of the vehicle plate 3. Then, under the influence of gravity, the vehicle plate 3 moves toward the side close to the support plate 22. The support plate 22 then presses the shock-absorbing spring 21, causing the shock-absorbing spring 21 to contract under pressure. In the process of transporting the cargo, the shock-absorbing spring 21 always pushes the cargo in the opposite direction, avoiding vibration during transportation and causing damage to the cargo. When the car plate 3 presses the support plate 22, the car plate 3 drives the movable groove 31 to move, and the movable groove 31 moves toward the side close to the fixed block 17, so that the fixed block 17 moves toward the depth of the movable groove 31. Then, during the bend transportation, the bracket 1 produces a certain deflection, and then the bracket 1 drives the rotating groove 15 to rotate. Since the rotating shaft 16 is rotatably connected to the rotating groove 15, and the cargo compartment can always be perpendicular to the horizontal plane under the influence of gravity, the car plate 3 drives the movable groove 31 to rotate. When the movable groove 31 rotates, it drives the fixed block 17 to rotate, and the fixed block 17 drives the rotating shaft 16 to rotate, so that the rotating shaft 16 deflects around the axis of the rotating groove 15, thereby ensuring the stability of the cargo compartment during the bend transportation; When there is no cargo compartment or cargo in the carriage, the push plate 47 is at the top of its travel, the sliding post 431 is at the top of the vertical slot 43, the first hinge plate 45 is retracted in the limiting slot 44, and the first support wheel 49 is in rolling connection with the track surface, while the second support wheel 50 and the third support wheel 51 are both in a state of being out of track. At this time, when the suspension moves on the track, the resistance generated is small, thereby reducing energy consumption. When the cargo box acts on the surface of the vehicle plate 3, since the upper surface of the push plate 47 is in the same plane as the upper surface of the vehicle plate 3, part of the side of the cargo box acts on the surface of the push plate 47, and the cargo box and the cargo also exert a pressing force on the push plate 47, thereby pushing the plate 47 to move toward the side close to the vertical groove 43. When the push plate 47 moves, it drives the push rod 46 to move, so that the push rod 46 continuously extends into the sliding cavity 42. The push rod 46 moves, driving the sliding post 431 to move. The sliding post 431 moves vertically along the vertical slot 43. When the sliding post 431 moves, the first hinge plates 45 provided on both sides move. The first hinge plates 45 move along the limiting slots 44, so that the side of the first hinge plates 45 away from the sliding post 431 moves toward the side close to the track wheel 14. The first hinge plate 45 drives the second hinge plate 48 to rotate during its movement. The second hinge plate 48 rotates from the side away from the first support wheel 49 to the side close to the track wheel 14. The second hinge plate 48 drives the second support wheel 50 and the third support wheel 51 to rotate during its rotation. When the sliding post 431 moves to the bottom of the vertical slot 43, the sliding post 431 is at its farthest travel, the second hinge plate 48 is parallel to the track, and the first support wheel 49, the second support wheel 50 and the third support wheel 51 are in contact with the track surface and are rollingly connected to the track. The change in the gravity of the cargo compartment and the cargo causes the distance moved by the cargo compartment pressing the push plate 47 to vary, thereby changing the angle between the second hinge plate 48 and the track, thereby changing whether the second support wheel 50 and the third support wheel 51 are in contact with the track; When the cargo compartment is in a heavily loaded state, the second hinged plate 48 is parallel to the track, and the first support wheel 49, the second support wheel 50 and the third support wheel 51 are in contact with the track surface and provide support force to the cargo compartment, thereby increasing the load capacity of the cargo compartment and dispersing the gravity of the cargo compartment; When the cargo compartment is moderately loaded, the second hinged plate 48 is at an angle of less than 30° to the track, and at this time only the first support wheel 49 and the second support wheel 50 are in contact with the track surface, so that the first support wheel 49 and the second support wheel 50 increase the supporting force of the cargo compartment, thereby increasing the carrying capacity while reducing the energy consumption generated by the same cargo.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A special anti-overturning heavy-load suspension for rails, characterized by: The invention comprises a bracket (1), wherein a row frame (11) is symmetrically provided at the front and rear ends of the bracket (1), a rotating frame (12) is symmetrically provided on both sides of the row frame (11), a transmission shaft (13) is provided in the rotating frame (12), and track wheels (14) are provided on both sides of the transmission shaft (13), a shock absorbing assembly (2) is provided on the top of the row frame (11), a vehicle plate (3) is provided on the side of the shock absorbing assembly (2) away from the row frame (11), and the vehicle plate (3) is used to place a cargo compartment, and support assemblies (4) are symmetrically provided on both sides of the bracket (1).

2. The track-specific anti-overturning heavy-load suspension according to claim 1, characterized in that: The shock absorbing assembly (2) is composed of two groups of shock absorbing springs (21) and a support plate (22). The two groups of shock absorbing springs (21) are symmetrically arranged above the two ends of the traveling frame (11), and the support plate (22) is arranged on the side of the shock absorbing springs (21) away from the traveling frame (11).

3. The track-specific anti-overturning heavy-load suspension according to claim 1, characterized in that: A rotating groove (15) is provided in the middle of the bracket (1), a rotating shaft (16) is provided in the rotating groove (15), the rotating shaft (16) is rotatably connected to the rotating groove (15), a fixed block (17) is provided on the rotating shaft (16), a movable groove (31) is provided on one side of the vehicle plate (3) close to the rotating groove (15), the fixed block (17) extends into the movable groove (31), and the fixed block (17) is slidably connected to the movable groove (31).

4. The track-specific anti-overturning heavy-load suspension according to claim 1, characterized in that: The support assembly (4) includes an extension block (41), which is arranged on one side of the bracket (1). A sliding cavity (42) is arranged inside the extension block (41), and the sliding cavity (42) is composed of a vertical groove (43) and two limiting grooves (44). The vertical groove (43) is arranged at the center of the sliding cavity (42), and the limiting grooves (44) are symmetrically arranged on both sides of the vertical groove (43).

5. The track-specific anti-overturning heavy-load suspension according to claim 4, characterized in that: A sliding column (431) is provided in the vertical groove (43), and the sliding column (431) is slidably connected to the vertical groove (43). A first hinge plate (45) is provided on both sides of the sliding column (431). A push rod (46) is provided in the middle of the sliding column (431), and the push rod (46) extends out of the sliding cavity (42). A push plate (47) is provided on the side of the push rod (46) away from the vertical groove (43). The upper surface of the push plate (47) is in the same plane as the upper surface of the vehicle plate (3), and a plurality of supporting springs are provided on the side of the push plate (47) close to the extension block (41).

6. The track-specific anti-overturning heavy-load suspension according to claim 5, characterized in that: A second hinge plate (48) is provided on a side of the first hinge plate (45) away from the sliding column (431), the first hinge plate (45) is hinged to the second hinge plate (48), and the second hinge plate (48) is provided with a first support wheel (49), a second support wheel (50) and a third support wheel (51).

7. The track-specific anti-overturning heavy-load suspension according to claim 6, characterized in that: A first support wheel (49) is provided at the hinge of the two second hinged plates (48), the first support wheel (49) is hinged to the second hinged plate (48), a third support wheel (51) is provided at the hinge of the first hinged plate (45) and the second hinged plate (48), a second support wheel (50) is provided between the first support wheel (49) and the third support wheel (51), and the first support wheel (49) and the third support wheel (51) are rotatably connected to the second hinged plate (48).

8. The track-specific anti-overturning heavy-load suspension according to claim 8, characterized in that: The diameter of the first support wheel (49) is the same as the diameter of the third support wheel (51), and the diameter of the second support wheel (50) is larger than the diameters of the first support wheel (49) and the third support wheel (51).

9. The track-specific anti-overturning heavy-load suspension according to claim 8, characterized in that: An extrusion groove (52) is provided on one side of the second hinge plate (48) close to the second supporting wheel (50), an extrusion ring (53) is provided in the extrusion groove (52), the extrusion ring (53) is slidably connected to the extrusion groove (52), the second supporting wheel (50) is rotatably connected to the extrusion ring (53), and an extrusion spring is symmetrically provided on one side of the extrusion ring (53) close to the extrusion groove (52).

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