Car washing device based on sedimentation tank

Abstract

The utility model discloses a car washing device based on a sedimentation tank, which belongs to the technical field of construction site auxiliary equipment and comprises a ground parking area, a drainage ditch, the sedimentation tank, a clean water tank and an operation platform. The drainage ditch, the sedimentation tank and the clean water tank sink relative to the ground parking area, the drainage ditch is communicated with the sedimentation tank, and the sedimentation tank and the clean water tank are adjacent and mutually communicated; the operation platform is positioned above the sedimentation tank and close to the drainage ditch; the ground parking area can accommodate a plurality of vehicles to be parked side by side in the length direction of the operation platform; the ground parking area is bordered with the drainage ditch; a plurality of water outlet branch pipes are arranged on the operation platform and are communicated with the clean water tank through a pump body; each water outlet branch pipe can be in an independent opening state, so that a plurality of vehicles can be simultaneously and independently washed; according to the car washing wastewater recycling device, car washing wastewater can be conveniently collected and recycled, and meanwhile the car washing convenience and efficiency can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of auxiliary equipment for construction sites, and particularly relates to a car washing device based on a sedimentation tank. Background Art

[0002] During the transportation and production process of vehicle equipment, due to the poor production site environment and the frequent use of vehicle equipment, dust and road pollution are inevitable. Therefore, in order to improve the construction site environment, construction sites need to set up sedimentation tanks or other effective wastewater treatment facilities to ensure that construction wastewater is effectively treated before being discharged.

[0003] Currently, car washing platforms and sedimentation tanks are relatively common at construction sites. In order to facilitate the recycling of car washing wastewater, in the prior art, the car washing wastewater of the car washing platform is mostly collected and sent to the sedimentation tank for sedimentation and then reused. Therefore, in order to facilitate the collection of the wastewater of the car washing platform, a sunken car washing platform is adopted in the prior art. However, due to the high height of construction vehicles at construction sites, the traditional sunken car washing platform makes it inconvenient for users to wash cars. In addition, in order to control the input cost and ensure the passage of construction vehicles, the sunken car washing platform usually only allows one vehicle to be washed and then another vehicle to be washed, resulting in low car washing efficiency. Summary of the Utility Model

[0004] Aiming at the deficiencies in the prior art, the utility model provides a car washing device based on a sedimentation tank, which can facilitate the collection and reuse of car washing wastewater, and at the same time improve the convenience and efficiency of car washing.

[0005] To achieve the above object, the utility model adopts the following technical solutions:

[0006] A car washing device based on a sedimentation tank includes a ground parking area, a drainage ditch, a sedimentation tank, a clear water tank and an operation platform; the drainage ditch, the sedimentation tank and the clear water tank are all sunken relative to the ground parking area, the drainage ditch is communicated with the sedimentation tank, and the sedimentation tank and the clear water tank are adjacent and communicate with each other; the operation platform is located above the sedimentation tank and close to the drainage ditch; the ground parking area can accommodate a number of vehicles parked side by side in the length direction of the operation platform; the ground parking area is adjacent to the drainage ditch so that the wastewater in the ground parking area can flow into the drainage ditch; a number of water outlet branch pipes are arranged on the operation platform, and the water outlet branch pipes are communicated with the clear water tank through a pump body; each of the water outlet branch pipes can be independently opened so as to simultaneously and independently wash multiple vehicles.

[0007] Optionally, there are two sedimentation tanks, the two sedimentation tanks are adjacent and communicate with each other, the first sedimentation tank is communicated with the drainage ditch, and the second sedimentation tank is communicated with the clear water tank; the two sedimentation tanks and the clear water tank are arranged to form a rectangular structure.

[0008] Optionally, the two sedimentation tanks are arranged side by side and share a wall, and the second sedimentation tank shares a wall with the clean water tank; at least one connecting port is provided on the wall body of the two sedimentation tanks and the wall body of the second sedimentation tank and the clean water tank.

[0009] Optionally, the clean water tank is located on the left or right side of the sedimentation tank, and the side wall of the sedimentation tank facing away from the clean water tank is a sloped side wall; a first fence of a semi-enclosed structure is arranged outside the rectangular structure, and the opening of the first fence is the location of the sloped side wall.

[0010] Optionally, the operating platform is erected above the sedimentation tank through steel beams; an escalator is provided on the operating platform to facilitate users to get on and off the operating platform; a grille cover is provided on the surface of the drainage ditch; the outlet of the pump body is connected to the main water outlet pipe, all the branch water outlet pipes are connected to the main water outlet pipe, and a control valve is provided at the starting end of the branch water outlet pipe.

[0011] Optionally, it also includes an extension platform, which includes a first platform and a second platform; the first platform is slidably connected to the operating platform and can slide along the length of the operating platform; the second platform is slidably connected to the first platform and one end can slide out of the first platform; when the second platform slides out of the first platform, the second platform is located directly above the ground parking area.

[0012] Optionally, the first platform is a box-type structure, and the second platform can be connected to the inside of the first platform in a retractable manner; a protective plate is provided at the extended end of the second platform; a first support plate is provided on the first platform near the drainage ditch; an extension arm is provided on the protective plate; the end of the extension arm away from the protective plate slides through the first support plate and is connected to the power assembly, so as to push and pull the second platform to move away from or close to the operating platform.

[0013] Optionally, a second support plate is further provided on the first platform; the second support plate is opposite to the first support plate, the power assembly comprises a motor, a screw and a transmission box; the screw is rotatably connected between the first support plate and the second support plate; the screw is connected to the motor through the transmission box; the end of the extension arm away from the protective plate is connected to the moving part of the screw through a connecting block.

[0014] Optionally, the distance between the second support plate and the first support plate is smaller than the axial dimension of the first platform in the screw rod; at least one optical axis is provided between the first support plate and the second support plate, and the connecting block is slidably connected to the optical axis;

[0015] There are two groups of the extension arms, which are respectively located on opposite sides of the protection plate. The extension arms on the same side of the protection plate are connected to the same power assembly. The first support plate and the second support plate are connected with an inner protection plate and an outer protection plate that can wrap the power assembly inside. There are two corresponding first support plates, second support plates, power assemblies, inner protection plates and outer protection plates respectively. There is a passage for the user to walk through between the two inner protection plates.

[0016] Optionally, a semi-enclosed second fence is arranged on the operation platform. A number of columns are arranged on the side of the operation platform close to the drainage ditch. The multiple columns extend along their length direction. A protective door that can be opened and closed is connected between any two adjacent columns. When the extension platform is in a contracted state, the protective door is located outside the extension platform. The second fence and the protective door form a closed structure in the horizontal plane.

[0017] The beneficial effects of the present utility model are as follows:

[0018] (1) The drainage ditch, the sedimentation tank and the clear water tank all sink relative to the ground parking area. The drainage ditch is adjacent to the ground parking area, so that the waste water in the ground parking area can be conveniently collected and reused. The operation platform is located above the sedimentation tank, thus avoiding the inconvenience of car washing caused by the excessive height of the vehicle. Multiple vehicles to be washed are placed side by side along the length direction of the operation platform. At the same time, a plurality of water outlet branch pipes are arranged on the operation platform, so as to facilitate the simultaneous and independent washing of multiple vehicles.

[0019] (2) The setting of the extension platform can wash vehicles with longer lengths, thereby improving the compatibility of the entire car washing device. The extension platform includes a first platform and a second platform. The first platform can be slidably connected to the operation platform, so that the extension platform can move to any position in the length direction of the operation platform, which is convenient for use. Description of the Drawings

[0020] Figure 1 is the overall structural schematic diagram of the present utility model;

[0021] Figure 2 is the enlarged top view structural schematic diagram of the extension platform in the present utility model;

[0022] Figure 3 is the right side view of the extension platform in the present utility model.

[0023] In the figure, the markings are as follows: 1 is the ground parking area, 2 is the drainage ditch, 3 is the sedimentation tank, 4 is the clear water tank, 5 is the operation platform, 51 is the second fence, 6 is the communication port, 7 is the escalator, 8 is the extended platform, 81 is the first platform, 811 is the first support plate, 812 is the second support plate, 813 is the inner protection plate, 814 is the outer protection plate, 82 is the second platform, 83 is the protection plate, 84 is the extension arm, 85 is the optical axis, 86 is the connection block, 87 is the motor, 88 is the lead screw, and 89 is the transmission box. Detailed implementation mode

[0024] The present utility model will be described in detail below with reference to the accompanying drawings.

[0025] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "rear", etc. cited in the utility model are only for the convenience of clear narration, rather than used to limit the scope of implementation of the present utility model. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present utility model.

[0026] As Figure 1 shown, a car washing device based on a sedimentation tank is provided, including a ground parking area 1, a drainage ditch 2, a sedimentation tank 3, a clear water tank 4 and an operation platform 5; the drainage ditch 2, the sedimentation tank 3 and the clear water tank 4 are all sunken relative to the ground parking area 1, and the bottom elevations of the sedimentation tank 3 and the clear water tank 4 are both -1.8 m; the bottom elevation of the drainage ditch 2 is -0.30 m, and the drainage ditch 2 communicates with the sedimentation tank 3; the sedimentation tank 3 and the clear water tank 4 are adjacent to each other and communicate with each other; the operation platform 5 is located above the sedimentation tank 3 and close to the drainage ditch 2, that is, the projection of one side of the operation platform 5 coincides with the edge of the drainage ditch 2 after projection; the ground parking area 1 can accommodate a number of vehicles parked side by side in the length direction of the operation platform 5; the ground parking area 1 is adjacent to the drainage ditch 2 so that the wastewater in the ground parking area 1 flows into the drainage ditch 2; a number of outlet branch pipes (not shown in the figure) are arranged on the operation platform 5, and the outlet branch pipes are communicated with the clear water tank 4 through a pump body; each of the outlet branch pipes can be in an independent open state so as to simultaneously and independently wash multiple vehicles, that is, multiple vehicles are parked in the ground parking area 1, and multiple users stand on the operation platform 5 to independently wash multiple vehicles. The wastewater flows into the drainage ditch 2 through the ground parking area 1, and the wastewater in the drainage ditch 2 flows into the sedimentation tank 3 for sedimentation and then returns to the clear water tank 4 to realize the recycling of wastewater; since the tail height of the concrete mixer truck commonly used in construction sites is higher than the head, the operation platform 5 erected above the sedimentation tank 3 can effectively wash the mixer truck from the tail, thus avoiding the inconvenience of washing caused by the excessive height of the vehicle; in addition, since the ground parking area 1 is located on the ground, its position can be determined directly by means of artificial planning without excessive investment cost.

[0027] To improve the treatment effect of wastewater, there are two sedimentation tanks 3, which are adjacent and interconnected. The first sedimentation tank 3 is communicated with the drainage ditch 2, and the second sedimentation tank 3 is communicated with the clear water tank 4; the two sedimentation tanks 3 and the clear water tank 4 are arranged to form a rectangular structure; optionally, the two sedimentation tanks 3 are arranged side by side front and back in the form of a common wall, and the clear water tank 4 is located on the left or right side of the two sedimentation tanks 3. Specifically, the horizontal plane size of the two sedimentation tanks 3 is 12.8 * 3.7 m, and the horizontal plane size of the clear water tank 4 is 7.6 m * 3 m; the second sedimentation tank 3 and the clear water tank 4 share a common wall; at least one communication port 6 is provided on the wall body where the two sedimentation tanks 3 share a common wall and on the wall body where the second sedimentation tank 3 and the clear water tank 4 share a common wall; through the setting of the communication port 6, the two sedimentation tanks 3 are communicated, and the second sedimentation tank 3 and the clear water tank 4 are communicated. The drainage ditch 2 can be communicated with the first sedimentation tank 3 by setting a water inlet pipe; the height of the water inlet pipe from the ground is -0.5 m, the height of the communication port 6 on the side wall where the two sedimentation tanks 3 share a common wall from the ground is -0.55 m, and the height of the communication port 6 on the side wall where the second sedimentation tank 3 and the clear water tank 4 share a common wall from the inside is -0.6 m; the bottom slope of the drainage ditch 2 is usually 1%, which is convenient for wastewater to flow from one end of the drainage ditch 2 to the water inlet pipe and then enter the first sedimentation tank 3.

[0028] Furthermore, the side wall of the sedimentation tank 3 facing away from the clear water tank 4 is a sloping side wall; a first fence with a semi - enclosed structure is arranged outside the rectangular structure formed by the arrangement of the sedimentation tank 3 and the clear water tank 4. The opening of the first fence is the position of the sloping side wall. The setting of the sloping side wall is for subsequent use of an excavator to clean the sludge and sundries in the sedimentation tank 3.

[0029] In some other embodiments, the two sedimentation tanks 3 and the clear water tank 4 can be arranged side by side front and back to form a rectangular structure (not shown in the figure), and the left or right side of the two sedimentation tanks 3 is a sloping side wall.

[0030] Specifically, the operation platform 5 is erected above the sedimentation tank 3 through steel beams; a ladder 7 is provided on the operation platform 5 for personnel to get on and off the operation platform 5; a grille cover plate is arranged on the surface of the drainage ditch 2, and the longitudinal section of the drainage ditch 2 is U-shaped. The grille cover plate covers the drainage ditch 2, and the grille cover plate can be connected to the drainage ditch 2 by screws or the like. Of course, a placement groove can also be provided on the drainage ditch 2 to place the grille cover plate in the placement groove; the outlet of the pump body is communicated with the total water outlet pipe, and all the water outlet branch pipes are connected to the total water outlet pipe, and a control valve is arranged at the starting end of the water outlet branch pipe. After the pump body is started, the clear water in the clear water tank 4 is pumped into the total water outlet pipe, and the user controls the water outlet of the water outlet branch pipe by opening or closing the control valve; the water outlet branch pipe is a flexible water pipe, which can be adjusted by the user for the use position, and a nozzle can be arranged at the water spraying end of the water outlet branch pipe; the structures of the pump body, the total water outlet pipe and the water outlet branch pipes (not shown in the figure) can be set with reference to the prior art. The total water outlet pipe extends along the length direction of the operation platform 5, and all the water outlet branch pipes are communicated with the total water outlet pipe.

[0031] In some other embodiments, such as Figure 2 and 3 shown, an extension platform 8 is further included. The extension platform 8 includes a first platform 81 and a second platform 82; the first platform 81 is slidably connected to the operation platform 5 and can slide along the length direction of the operation platform 5; specifically, an electric slide can be arranged on the operation platform 5, and the first platform 81 is fixed to the sliding part of the electric slide; of course, a slide rail can also be arranged on the operation platform 5, and the first platform 81 is slidably connected to the slide rail, and the first platform 81 is driven to slide by manual or other power; the second platform 82 is slidably connected to the first platform 81, and one end can slide out of the first platform 81; when the second platform 82 slides out of the first platform 81, the second platform 82 is directly above the ground parking area 1, that is, the sliding direction of the second platform 82 is perpendicular to the sliding direction of the first platform 81; the second platform 82 can be extended to adapt to the cleaning of vehicles with longer lengths; in order to avoid the influence of the sliding of the second platform 82 on the cleaning of other vehicles, the second platform 82 is relatively narrow and can be located between two vehicles after sliding out; of course, the width of the parking spaces in the parking area and the parking requirements can also be adjusted to ensure that the second platform 82 has enough telescopic space; it should be noted that the second platform 82 extends only after the first platform 81 moves into place.

[0032] Specifically, the first platform 81 is a box-type structure, and the second platform 82 can be connected to the inside of the first platform 81 in a retractable manner; a protective plate 83 is provided at the extended end of the second platform 82; a first support plate 811 is provided on the first platform 81 near the drainage ditch 2; an extension arm 84 is provided on the protective plate 83; the end of the extension arm 84 away from the protective plate 83 slides through the first support plate 811 and is connected to the power assembly, so as to push and pull the second platform 82 to move away from or close to the operating platform 5; after the power assembly pushes the extension arm 84, the extension arm 84 pushes the protective plate 83, and the protective plate 83 drives the second platform 82 to move away from the operating platform 5 to slide out.

[0033] Specifically, a second support plate 812 is also provided on the first platform 81; the second support plate 812 is opposite to the first support plate 811, and the power assembly includes a motor 87, a screw rod 88 and a transmission box 89; the screw rod 88 is rotatably connected between the first support plate 811 and the second support plate 812; the screw rod 88 is connected to the motor 87 through the transmission box 89, thereby driving the screw rod 88 to rotate forward and reverse; the end of the extension arm 84 away from the protective plate 83 is connected to the moving part of the screw rod 88 through the connecting block 86, and the connecting block 86 connects the moving part of the screw rod 88 and the extension arm 84. When the screw rod 88 rotates forward and reversely, the connecting block 86 moves along the axial direction of the screw rod 88, thereby pushing and pulling the extension arm 84, so as to realize the movement of the protective plate 83 and the second platform 82 to move closer to or away from the operating platform 5.

[0034] Specifically, the distance between the second support plate 812 and the first support plate 811 is smaller than the axial dimension of the first platform 81 in the screw rod 88, so that it is convenient for users to enter the first platform 81 from the operating platform 5, and then enter the second platform 82; at least one optical axis 85 is provided between the first support plate 811 and the second support plate 812; the connecting block 86 is slidably connected to the optical axis 85, and the optical axis 85 provides a guide for the movement of the connecting block 86, so as to ensure smooth pushing and pulling of the extension arm 84.

[0035] Specifically, there are two sets of the extension arms 84, which are respectively located on opposite sides of the protection plate 83. The extension arms 84 on the same side of the protection plate 83 are connected to the same power assembly. In this embodiment, there are four extension arms 84, which are grouped in pairs. The extension arms 84 on the same side of the protection plate 83 are connected to the same power assembly; an inner protection plate 813 and an outer protection plate 814 capable of wrapping the power assembly are connected to the first support plate 811 and the second support plate 812; there are two corresponding first support plates 811, second support plates 812, power assemblies, inner protection plates 813 and outer protection plates 814 respectively, and the two power assemblies act synchronously during use; there is a passage for the user to pass through between the two inner protection plates 813, so as to facilitate the user to enter the second platform 82 from the first platform 81. The settings of the inner protection plate 813 and the outer protection plate 814 can protect the user and the power assembly. For the sake of clarity, Figure 3 The outer protection plate 814, the motor 87 and the transmission case 89 are omitted.

[0036] In some other embodiments, the operation platform 5 is provided with a semi-enclosed second fence 51; several columns are provided on the side of the operation platform 5 close to the drainage ditch 2, and the plurality of columns extend along their length directions. A protective door (not shown in the figure) capable of opening and closing is connected between any two adjacent columns. When the extension platform 8 is in the retracted state, the protective door is located outside the extension platform 8, that is, when the protection plate 83 retracts to be directly above the operation platform 5, the extension platform 8 does not affect the opening and closing of the protective door; the second fence 51 and the protective door form a closed structure on the horizontal plane; the protective door is a push-pull structure or a hinged structure; it should be noted that the protective door is in a normally closed state; when the extension platform 8 needs to be used and the first platform 81 slides in place, the protective door at the corresponding position is opened so that the second platform 82 can slide out and the user can pass through.

[0037] The various embodiments in this specification are described in a progressive manner. The key points of each embodiment are the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0038] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A car washing device based on a sedimentation tank, characterized in that: The utility model comprises a ground parking area (1), a drainage ditch (2), a sedimentation tank (3), a clean water tank (4) and an operating platform (5); the drainage ditch (2), the sedimentation tank (3) and the clean water tank (4) are all sunken relative to the ground parking area (1), the drainage ditch (2) is communicated with the sedimentation tank (3), and the sedimentation tank (3) and the clean water tank (4) are adjacent to each other and interpenetrate each other; the operating platform (5) is located at the upper part of the sedimentation tank (3) and close to the drainage ditch (2); the ground parking area (1) can accommodate a plurality of vehicles parked side by side in the length direction of the operating platform (5); the ground parking area (1) is adjacent to the drainage ditch (2) so that the waste water of the ground parking area (1) flows into the drainage ditch (2); a plurality of water outlet branches are arranged on the operating platform (5), and the water outlet branches are communicated with the clean water tank (4) through a pump body; each of the water outlet branches can be in an independent open state so as to simultaneously and independently wash a plurality of vehicles.

2. A car washing device based on a sedimentation tank according to claim 1, characterized in that: There are two sedimentation tanks (3), which are adjacent to each other and communicate with each other, wherein the first sedimentation tank (3) is communicated with the drainage ditch (2), and the second sedimentation tank (3) is communicated with the clean water tank (4); the two sedimentation tanks (3) and the clean water tank (4) are arranged to form a rectangular structure.

3. A car washing device based on a sedimentation tank according to claim 2, characterized in that: The two sedimentation tanks (3) are arranged side by side in front and back and share a wall, and the second sedimentation tank (3) and the clean water tank (4) share a wall; at least one connecting port (6) is provided on the wall body shared by the two sedimentation tanks (3) and the wall body shared by the second sedimentation tank (3) and the clean water tank (4).

4. A car washing device based on a sedimentation tank according to claim 2, characterized in that: The clean water tank (4) is located on the left or right side of the sedimentation tank (3), and the side wall of the sedimentation tank (3) facing away from the clean water tank (4) is a sloped side wall; a first fence of a semi-enclosed structure is arranged outside the rectangular structure, and the opening of the first fence is the location of the sloped side wall.

5. A car washing device based on a sedimentation tank according to claim 1, characterized in that: The operating platform (5) is erected above the sedimentation tank (3) via steel beams; an escalator (7) is provided on the operating platform (5) to facilitate users to go up and down the operating platform (5); a grille cover is provided on the surface of the drainage ditch (2); the outlet of the pump body is connected to the main water outlet pipe, all the branch water outlet pipes are connected to the main water outlet pipe, and a control valve is provided at the starting end of each branch water outlet pipe.

6. A car washing device based on a sedimentation tank according to claim 1, characterized in that: It also comprises an extension platform (8), wherein the extension platform (8) comprises a first platform (81) and a second platform (82); the first platform (81) is slidably connected to the operating platform (5) and is capable of sliding along the length direction of the operating platform (5); The second platform (82) is slidably connected to the first platform (81), and one end of the second platform (82) can slide out of the first platform (81); when the second platform (82) slides out of the first platform (81), the second platform (82) is located directly above the ground parking area (1).

7. A car washing device based on a sedimentation tank according to claim 6, characterized in that: The first platform (81) is a box-type structure, and the second platform (82) can be connected to the inside of the first platform (81) in a pull-out manner; a protective plate (83) is provided at the protruding end of the second platform (82); a first support plate (811) is provided on the first platform (81) near the drainage ditch (2); an extension arm (84) is provided on the protective plate (83); the end of the extension arm (84) away from the protective plate (83) slides through the first support plate (811) and is connected to a power assembly so as to push and pull the second platform (82) to move in a direction away from or close to the operating platform (5).

8. A car washing device based on a sedimentation tank according to claim 7, characterized in that: A second support plate (812) is also provided on the first platform (81); the second support plate (812) is opposite to the first support plate (811), and the power assembly comprises a motor (87), a screw rod (88) and a transmission box (89); the screw rod (88) is rotatably connected between the first support plate (811) and the second support plate (812); the screw rod (88) is connected to the motor (87) through the transmission box (89); and the end of the extension arm (84) away from the protective plate (83) is connected to the moving part of the screw rod (88) through a connecting block (86).

9. A car washing device based on a sedimentation tank according to claim 8, characterized in that: The distance between the second support plate (812) and the first support plate (811) is smaller than the axial dimension of the first platform (81) in the screw rod (88); at least one optical axis (85) is provided between the first support plate (811) and the second support plate (812), and the connecting block (86) is slidably connected to the optical axis (85); There are two groups of extension arms (84), which are respectively located on opposite sides of the protective plate (83); the extension arms (84) located on the same side of the protective plate (83) are connected to the same power assembly; the first support plate (811) and the second support plate (812) are connected with an inner guard plate (813) and an outer guard plate (814) capable of wrapping the power assembly; there are two of each of the first support plate (811), the second support plate (812), the power assembly, the inner guard plate (813) and the outer guard plate (814); and there is a passage between the two inner guard plates (813) for accommodating users to pass through.

10. A car washing device based on a sedimentation tank according to claim 6, characterized in that: A semi-enclosed second fence (51) is provided on the operating platform (5); a plurality of columns are provided on the operating platform (5) near the drainage ditch (2), the plurality of columns extending along the length direction thereof, and a protective door capable of opening and closing is connected between any two adjacent columns; when the extension platform (8) is in a retracted state, the protective door is located outside the extension platform (8), and the second fence (51) and the protective door form a closed structure in a horizontal plane.

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