Trolley for transporting HDPE (High-Density Polyethylene) pipeline

Abstract

The utility model relates to the technical field of pipeline transportation, in particular to a trolley for transporting HDPE (high-density polyethylene) pipelines, which comprises a hollow trolley body filled with foamed plastic. Steel cam sets are arranged on the two sides of the vehicle body and can be embedded into the shipping track. The trolley effectively solves the problems that a traditional delivery trolley is inconvenient to position, insufficient in bearing capacity and difficult to recycle after entering the sea in the process of transporting large-diameter HDPE pipelines, and the convenience, reliability and construction efficiency of the HDPE pipelines in the delivery process are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of pipeline transportation technology, and in particular to a trolley for transporting HDPE pipelines. Background Technology

[0002] HDPE (High Density Polyethylene) pipes have excellent corrosion resistance, resisting the erosion of salt and other chemicals in seawater, and are therefore commonly used for seawater transportation. When HDPE pipes are used as water intake pipes in seawater cooling systems, large-diameter (≥3000mm) HDPE pipes are often required. Before these HDPE pipes are introduced into the water, ballast blocks need to be placed on a transport trolley on land. Then, the HDPE pipes are connected to the ballast blocks, and the transport trolley moves along the transport track to bring the HDPE pipes into the sea.

[0003] Currently, commonly used transport trolleys, such as the Chinese utility model patent with publication number CN219822701U, disclose a steel pipe transport device that uses a concave wheel structure commonly used in rail transport. However, when transporting HDPE pipes, due to the large self-weight of HDPE pipes (≥1t) and the need for the track beam to be designed with a certain inclination angle, conventional convex tracks are not suitable. Currently, for the transport of large HDPE pipes (diameter ≥3000mm, self-weight >1t) that need to be extended from the land to the sea, the track is often designed with a concave cross-section (e.g., channel steel). Conventional concave wheel transport trolleys have insufficient load-bearing capacity, are not easy to position with the track during hoisting, and conventional transport trolleys sink as soon as they enter the water, making them difficult to recover after entering the sea, resulting in low construction efficiency. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of existing transport trolleys, such as difficulty in positioning with the transport track during hoisting and inability to float after entering the sea, making them difficult to recover. This invention provides a trolley for transporting HDPE pipes.

[0005] In a first aspect, the present invention provides a trolley for transporting HDPE pipes, comprising a hollow body filled with foam plastic; steel cam assemblies are provided on both sides of the body, and the steel cam assemblies can be embedded in the transport track.

[0006] This utility model provides a trolley for transporting HDPE pipes. The trolley body is filled with foam plastic, a lightweight material with strong buoyancy. This prevents the trolley from sinking immediately after transporting the HDPE pipes to the sea and completing the sea entry operation, facilitating smooth recovery of the pipes after entry into the sea. This significantly improves construction efficiency and reduces manual labor. Unlike traditional trolleys using concave wheels, this utility model uses steel cams. During hoisting, the cam assembly can quickly engage with the concave track of the transport rail, facilitating trolley positioning during hoisting. The steel cams have high strength and durability, reliably supporting large-diameter HDPE pipes weighing over 1 ton, while ensuring stable and smooth transport without tilting or slipping due to insufficient load-bearing capacity, thus improving safety. The steel cams and concave track adapt well to changes in the transport rail angle, providing greater stability than ordinary concave wheels and steel rails, making on-site construction more convenient, and ensuring the stability of the trolley during transport on inclined tracks.

[0007] The trolley for transporting HDPE pipes provided by this utility model effectively solves the problems of inconvenient positioning, insufficient load-bearing capacity, and difficulty in recovery after entering the sea in the process of transporting large-diameter HDPE pipes by traditional trolleys, and greatly improves the convenience, reliability and construction efficiency of HDPE pipe transportation process.

[0008] Preferably, the vehicle body includes an outer frame and an inner reinforcing beam, the outer frame surrounding the foam plastic, and the inner reinforcing beam connecting at least two sides of the outer frame.

[0009] This structural design, combining an outer frame with internal reinforcing beams, makes the trolley structure more robust. The outer frame provides overall protection around the foam plastic, while the internal reinforcing beams further enhance the frame's support capacity, enabling the trolley to more effectively distribute and bear the load from heavy-duty HDPE pipes, preventing frame deformation or damage due to overloading.

[0010] Preferably, the internal reinforcing beams are arranged in a crisscross pattern.

[0011] This structural design, with its crisscrossing layout forming a mesh-like support structure, makes the trolley more stable under heavy loads. This design increases the overall rigidity of the trolley, distributes the weight and impact force from the HDPE pipes, effectively prevents localized stress concentration, and reduces the risk of trolley deformation.

[0012] Preferably, it further includes a limiting device for restricting the movement of the ballast block along the moving direction of the steel cam assembly. The limiting device is rotatably connected to the vehicle body and includes a rotating shaft and a baffle plate. The rotating shaft is fixedly connected to the vehicle body, and the baffle plate is rotatable around the rotating shaft.

[0013] This structural design allows the baffle to rotate around the pivot axis, enabling it to be rotated to a non-obstructing position during loading and unloading. After securing the ballast block, the baffle is rotated back to the limiting position, thus firmly fixing the ballast block. The limiting device restricts the movement of the ballast block along the steel cam assembly via the baffle, preventing accidental slippage due to inertia or vibration during transportation or hoisting. This ensures the safety of the trolley during transport and reduces potential safety hazards caused by ballast block displacement.

[0014] Preferably, the number of limiting devices is at least four, and the limiting devices are evenly distributed on both sides of the vehicle body.

[0015] With this structural design, at least four limiting devices are evenly distributed on both sides of the vehicle body, which can restrict the ballast blocks from multiple directions, effectively preventing the ballast blocks from moving or shifting due to inertia or external forces. This multi-point limiting and fixing method is more stable than a single limiting position, ensuring that the ballast blocks remain in a stable position during transportation and avoiding the risk of displacement or sliding.

[0016] Preferably, it further includes a connecting pin lug, which is fixedly connected to the vehicle body, and the position of the connecting pin lug corresponds to the position of the steel cam assembly; the connecting pin lug includes a lug plate and a pin detachably connected to the lug plate.

[0017] This structural design, with its lugs and pins, allows for quick assembly and disassembly when needed, eliminating the need for complex tools, effectively simplifying the operation process and improving construction efficiency. During use, adjacent trolleys can be connected in series via the connecting lugs, facilitating the synchronous towing of the trolleys on the transport track to transport HDPE pipes into the sea.

[0018] Preferably, the steel cam assembly includes a wheel, which is sleeved on a wheel axle via a bearing. The wheel axle is connected to a clamping plate, which is fixedly connected to the vehicle body. A cover is sleeved on the wheel axle and simultaneously clamps the axial ends of the wheel and the bearing.

[0019] This structural design allows the wheels to be smoothly connected to the axle via bearings, ensuring smooth rotation during trolley operation, reducing frictional resistance and improving operational efficiency. Simultaneously, the axle is connected to a clamping plate and secured to the trolley body, maintaining the stability of the entire wheel assembly during operation and minimizing loosening or misalignment caused by wheel stress. This stable connection enhances the trolley's structural strength, meeting the demands of high-load transportation and extending its service life. Furthermore, the cover, fitted onto the axle, secures the wheel and bearing axially, effectively preventing axial slippage or bearing displacement, and also provides protection against dust, moisture, or other impurities entering the bearing, thus improving the durability and reliability of the wheel assembly.

[0020] Preferably, the bearing is a tapered roller bearing.

[0021] This structural design prioritizes tapered roller bearings, which possess high load-bearing capacity and can withstand heavy loads, making them particularly suitable for transporting heavy HDPE pipes and ensuring the safety and stability of the trolley under various operating conditions. Secondly, their excellent impact resistance effectively disperses the pressure applied to the bearings, enhancing the trolley's durability. Furthermore, the low coefficient of friction of tapered roller bearings minimizes energy loss during rotation, thereby improving the trolley's operating efficiency, reducing power consumption, and extending equipment lifespan.

[0022] Preferably, a first sealing ring is provided between the transparent cover and the wheel, and a second sealing ring and a third sealing ring are provided between the transparent cover and the wheel axle. The second sealing ring and the third sealing ring are arranged side by side, with the second sealing ring being further outward than the third sealing ring.

[0023] This structural design, using multiple sealing rings between the cover and the wheel and axle, effectively prevents moisture, dust, and other contaminants from entering the bearings and wheel interior, and avoids seawater corrosion of the steel cam assembly. This sealing design significantly enhances the overall structural protection, extends component lifespan, and reduces the risk of failure due to environmental factors.

[0024] Preferably, the first sealing ring and the third sealing ring are O-rings, and the second sealing ring is a lip seal.

[0025] With this structural design, the O-ring, due to its simple annular design, can uniformly seal the contact surface under compression, providing excellent sealing performance and preventing liquid leakage. Simultaneously, the lip design of the lip seal can create additional sealing effects under axial and radial pressure, further improving the overall sealing performance and ensuring that the trolley is not affected by external contaminants during operation.

[0026] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0027] 1. The trolley for transporting HDPE pipes provided by this utility model is filled with foam plastic inside the trolley body. This lightweight material has strong buoyancy, so that the trolley will not sink immediately after transporting the HDPE pipes to the seaside and completing the sea entry operation. This facilitates the smooth recovery of the pipes after they enter the sea, significantly improving construction efficiency and reducing the workload of manual operation. Unlike traditional trolleys that use concave wheels, the trolley provided by this utility model uses steel cams. During hoisting, the cam assembly can quickly engage with the concave track of the transport rail, which facilitates the positioning of the trolley during hoisting. The steel cam has high strength and durability and can reliably support large-diameter HDPE pipes weighing more than 1 ton. At the same time, it ensures that the trolley is stable and smooth during transportation and will not tilt or slip due to insufficient load-bearing capacity, thus improving safety. The steel cam and the concave track can adapt well to the angle changes of the transport rail. Compared with the ordinary concave wheel and steel rail, the engagement is more stable, making on-site construction more convenient and ensuring the stability of the trolley during transportation on the inclined track.

[0028] 2. The trolley for HDPE pipe transportation provided by this utility model effectively solves the problems of inconvenient positioning, insufficient load-bearing capacity, and difficulty in recovery after entering the sea in the process of transporting large-diameter HDPE pipes by traditional transportation trolleys, and greatly improves the convenience, reliability and construction efficiency of HDPE pipe transportation process. Attached Figure Description

[0029] Figure 1 This is a front view of the trolley used for shipping HDPE pipes.

[0030] Figure 2 A top view of the trolley used for shipping HDPE pipes;

[0031] Figure 3 Side view of the trolley used for shipping HDPE pipes;

[0032] Figure 4 This is a schematic diagram of a steel cam assembly.

[0033] Marked in the image:

[0034] 1-Car body, 11-Outer frame, 12-Internal reinforcing beam, 2-Foam plastic, 3-Steel cam assembly, 31-Wheel, 32-Bearing, 33-Wheel axle, 34-Clamping plate, 35-Through cover, 41-Shaft, 42-Baffle plate, 51-Ear plate, 52-Pin, 61-First sealing ring, 62-Second sealing ring, 63-Third sealing ring, 100-Exit track. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0036] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of this utility model is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0037] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0038] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing between identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0039] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0040] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "equipped with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0041] Example 1

[0042] This embodiment provides a trolley for transporting HDPE pipes. The trolley is used to transport ballast blocks and large HDPE pipes (diameter ≥3000mm, weight >1t) from the land side into the water along a concave track (e.g., channel steel).

[0043] Specific examples Figure 1 As shown, the trolley for shipping HDPE pipes includes a hollow body 1, and the body 1 is filled with foam plastic 2; specifically, for example... Figure 2 As shown, the vehicle body 1 includes an outer frame 11 and internal reinforcing beams 12. The outer frame 11 can be rectangular, and it surrounds the foam plastic 2 from all four sides. The internal reinforcing beams 12 connect at least two sides of the outer frame 11. Specifically, the internal reinforcing beams 12 can be arranged in a crisscross pattern, for example... Figure 2 The internal reinforcing beams 12 are arranged in a crisscross pattern on the upper and lower surfaces of the outer frame 11. Foamed plastic 2, also known as polystyrene foam, is filled inside the vehicle body 1. This structural arrangement, combining the outer frame 11 and the internal reinforcing beams 12, makes the trolley structure more robust. The outer frame 11 provides overall protection around the foamed plastic 2, while the internal reinforcing beams 12 further strengthen the frame's support capacity, enabling the trolley to more effectively distribute and bear the load from the heavy HDPE pipes, preventing frame deformation or damage due to overweight. The foamed plastic 2 filling the interior of the vehicle body 1 also reduces the trolley's weight to some extent, facilitating subsequent lifting.

[0044] The 12 internal reinforcing beams, arranged in a crisscross pattern, form a mesh support structure, making the trolley more stable under heavy loads. This structural design increases the overall rigidity of the trolley, distributes the weight and impact force from the HDPE pipes, effectively prevents localized stress concentration, and reduces the risk of trolley deformation.

[0045] Steel cam assemblies 3 are installed on both sides of the vehicle body 1. Specifically, for example... Figures 1-3As shown, the vehicle body 1 has a rectangular structure, and the number of steel cam groups 3 can be four, with the four steel cam groups 3 symmetrically distributed on both sides of the long axis of the vehicle body 1.

[0046] like Figure 1 As shown, the transport track 100 is a concave track beam. For example, 10# channel steel can be used as the track beam, and the steel cam assembly 3 can be embedded in the transport track 100.

[0047] Furthermore, such as Figure 3 As shown, the trolley for transporting HDPE pipes provided in this embodiment also includes a limiting device. The limiting device is used to restrict the movement of the ballast block along the moving direction of the steel cam assembly 3, for example... Figure 3 The middle limiting device is used to restrict the movement of the ballast blocks on the vehicle body 1 along the short side direction (left-right direction) of the vehicle body 1. The limiting device is rotatably connected to the vehicle body 1. Specifically, the limiting device includes a rotating shaft 41 and a baffle 42. The rotating shaft 41 is fixedly connected to the vehicle body 1, and the baffle 42 can rotate around the rotating shaft 41. With this structural arrangement, since the baffle 42 can rotate around the rotating shaft 41, this design allows the baffle 42 to be rotated to a non-obstructing position (e.g., during loading and unloading). Figure 1 The baffle plate 42 on the right side is in a flat position. Then, after fixing the ballast block, rotate the baffle plate 42 back to the limit position (e.g., Figure 1 The baffle 42 on the left side is in the upright position, thus firmly fixing the ballast block. The limiting device restricts the movement direction of the ballast block along the steel cam assembly 3 through the baffle 42, preventing the ballast block from accidentally sliding due to inertia or vibration during transportation or hoisting, ensuring the safety of the trolley during the transportation process, and reducing the safety hazards that may be caused by the displacement of the ballast block.

[0048] Furthermore, in this embodiment, the number of limiting devices is at least four, and the limiting devices are evenly distributed on both sides of the vehicle body 1. Specifically, for example... Figure 2 As shown, four limiting devices are symmetrically distributed on both sides of the long axis of the vehicle body 1. The four limiting devices, evenly distributed on both sides of the vehicle body 1, can restrict the ballast block from multiple directions, effectively preventing the ballast block from moving or shifting due to inertia or external forces. This multi-point limiting and fixing method is more stable than a single limiting position, ensuring that the ballast block remains in a stable position during transportation and avoiding the risk of offset or slippage.

[0049] Furthermore, such as Figure 2 , Figure 3As shown, the trolley for transporting HDPE pipes provided in this embodiment also includes a connecting pin lug, which is fixedly connected to the trolley body 1. The position of the connecting pin lug corresponds to the position of the steel cam assembly 3. The connecting pin lug includes a lug 51 and a pin 52 detachably connected to the lug 51. The design of the lug 51 and the pin 52 allows for quick assembly and disassembly when needed, without the need for complex tools, effectively simplifying the operation process and improving construction efficiency. In use, adjacent trolleys can be connected in series using the connecting pin lug and ropes, facilitating the synchronous towing of the trolleys on the transport track 100 to transport HDPE pipes into the sea.

[0050] The trolley for transporting HDPE pipes provided in this embodiment has a body 1 filled with foam plastic 2. This lightweight material has strong buoyancy, preventing the trolley from sinking immediately after transporting the HDPE pipes to the sea and completing the sea entry operation. This facilitates smooth recovery of the pipes after they enter the sea, significantly improving construction efficiency and reducing manual labor. Unlike traditional trolleys that use concave wheels, the trolley provided in this invention uses steel cams. During hoisting, the cam assembly can quickly engage with the concave track of the transport track 100, facilitating the positioning of the trolley during hoisting. The steel cams have high strength and durability, reliably supporting large-diameter HDPE pipes and ballast blocks weighing over 1 ton. This ensures the trolley remains stable and smooth during transport, preventing tilting or slippage due to insufficient load-bearing capacity, thus improving safety. The steel cams and concave track can adapt well to changes in the angle of the transport track 100, providing greater stability than the combination of ordinary concave wheels and steel rails, making on-site construction more convenient, and ensuring the stability of the trolley during transport on inclined tracks.

[0051] The trolley for HDPE pipe transportation provided in this embodiment effectively solves the problems of inconvenient positioning, insufficient load-bearing capacity, and difficulty in recovery after entering the sea in the process of transporting large-diameter HDPE pipes by traditional transportation trolleys, and greatly improves the convenience, reliability and construction efficiency of HDPE pipe transportation process.

[0052] Example 2

[0053] Based on Example 1, such as Figure 4As shown, in this embodiment, the steel cam assembly 3 includes a wheel 31, which is sleeved on a wheel axle 33 via a bearing 32. Preferably, the bearing 32 is a tapered roller bearing. The wheel axle 33 is connected to a clamping plate 34, which is fixedly connected to the vehicle body 1. A cover 35 is sleeved on the wheel axle 33, simultaneously clamping the axial ends of the wheel 31 and the bearing 32. During use, the bearing cavity of the bearing 32 is filled with No. 2 lithium-based grease. With this structural arrangement, the wheel 31 is sleeved on the wheel axle 33 via the bearing 32, allowing the wheel 31 to rotate smoothly during vehicle operation, reducing frictional resistance and improving the vehicle's operating efficiency. Simultaneously, the wheel axle 33 is connected to the clamping plate 34 and fixed to the vehicle body 1 via the clamping plate 34, ensuring the entire wheel 31 assembly remains stable during operation and reducing loosening or displacement caused by force on the wheel 31. This stable connection enhances the structural strength of the vehicle, adapts to the needs of high-load transportation, and extends the vehicle's service life. In addition, the cover 35 is fitted onto the wheel axle 33 and clamps the axial ends of the wheel 31 and the bearing 32. This not only effectively prevents the wheel axle 33 from sliding or the bearing 32 from shifting, but also provides protection, preventing dust, moisture or other impurities from entering the bearing 32, thereby improving the durability and reliability of the wheel 31 assembly.

[0054] Furthermore, such as Figure 4 As shown, a first sealing ring 61 is provided between the cover 35 and the wheel 31. The first sealing ring 61 can be an O-ring. A second sealing ring 62 and a third sealing ring 63 are provided between the cover 35 and the wheel axle 33. The second sealing ring 62 and the third sealing ring 63 are arranged side by side. The second sealing ring 62 is further out than the third sealing ring 63. The second sealing ring 62 can be a lip seal, and the third sealing ring 63 can be an O-ring. The inner diameter of all sealing rings is coated with lubricating grease.

[0055] By setting multiple sealing rings between the cover 35 and the wheel 31 and wheel axle 33, moisture, dust and other contaminants are effectively prevented from entering the bearing 32 and the interior of the wheel 31, and grease leakage is also well prevented. This sealing design significantly improves the overall structure's protective capability, extends the service life of components, and reduces the risk of failure caused by environmental factors.

[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A trolley for transporting HDPE pipes, characterized in that, The vehicle includes a hollow body (1) filled with foam plastic (2); steel cam sets (3) are provided on both sides of the body (1), and the steel cam sets (3) can be embedded in the transport track (100).

2. The trolley for transporting HDPE pipes according to claim 1, characterized in that, The vehicle body (1) includes an outer frame (11) and an inner reinforcing beam (12), the outer frame (11) surrounding the foam plastic (2), and the inner reinforcing beam (12) connecting at least two sides of the outer frame (11).

3. A trolley for transporting HDPE pipes according to claim 2, characterized in that, The internal reinforcing beams (12) are arranged in a crisscross pattern.

4. A trolley for transporting HDPE pipes according to claim 1, characterized in that, It also includes a limiting device for limiting the movement of the ballast block along the moving direction of the steel cam assembly (3). The limiting device is rotatably connected to the vehicle body (1). The limiting device includes a rotating shaft (41) and a baffle (42). The rotating shaft (41) is fixedly connected to the vehicle body (1), and the baffle (42) can rotate around the rotating shaft (41).

5. A trolley for transporting HDPE pipes according to claim 4, characterized in that, The number of limiting devices is at least four, and the limiting devices are evenly distributed on both sides of the vehicle body (1).

6. A trolley for transporting HDPE pipes according to claim 1, characterized in that, It also includes a connecting pin ear, which is fixedly connected to the vehicle body (1), and the position of the connecting pin ear corresponds to the position of the steel cam assembly (3); the connecting pin ear includes an ear piece (51) and a pin (52) detachably connected to the ear piece (51).

7. A trolley for transporting HDPE pipes according to claim 1, characterized in that, The steel cam assembly (3) includes a wheel (31), which is sleeved on a wheel axle (33) via a bearing (32). The wheel axle (33) is connected to a clamping plate (34), which is fixedly connected to the vehicle body (1). A cover (35) is sleeved on the wheel axle (33) and simultaneously clamps the axial ends of the wheel (31) and the bearing (32).

8. A trolley for transporting HDPE pipes according to claim 7, characterized in that, The bearing (32) is a tapered roller bearing.

9. A trolley for transporting HDPE pipes according to claim 7, characterized in that, A first sealing ring (61) is provided between the cover (35) and the wheel (31), and a second sealing ring (62) and a third sealing ring (63) are provided between the cover (35) and the wheel axle (33). The second sealing ring (62) and the third sealing ring (63) are arranged side by side, and the second sealing ring (62) is further out than the third sealing ring (63).

10. A trolley for transporting HDPE pipes according to claim 9, characterized in that, The first sealing ring (61) and the third sealing ring (63) are O-rings, and the second sealing ring (62) is a lip seal.

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