A trench construction method for municipal pipeline engineering

Abstract

A trench construction method for municipal pipeline projects relates to the technical field of trench construction, including S1 preliminary preparation, S2 construction site surveying and mapping, S3 trench excavation and construction, S4 trench backfilling, and S5 quality inspection and acceptance. The present invention is highly practical and very convenient to use. By providing a slope protection frame, the inner wall of the trench can be effectively protected from being eroded by rainwater or groundwater, thereby preventing the soil layer in the trench from having an excessively high water content. By providing a bearing frame, soil piled at the edge of the trench can be prevented from falling into the trench, thereby ensuring construction quality and protecting the personal safety of trench construction workers. Furthermore, soil backfilling can be facilitated, thereby improving work efficiency. By using this support device, the laying and installation of pipelines in the trench can be facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of trench construction, in particular to a trench construction method for municipal pipeline engineering. Background Art

[0002] Pipelines are one of the indispensable municipal facilities for urban construction. Pipelines are generally buried underground. Before laying the pipelines, trenches need to be dug on the ground, and then backfilled after the pipelines are laid. During the trenching process, soil will be piled on both sides of the trench. However, the weather for outdoor construction is also a necessary consideration. On rainy days, rainwater soaks the soil, causing the soil to have a high water content. The soil will then pile up into piles and flow back into the trench with the rainwater, affecting the construction. The fallen soil also threatens the personal safety of the construction workers in the trench, causing production safety accidents. After the construction is completed, backfilling the soil also requires a lot of time and the use of manpower and mechanical equipment. After the trench is dug, large equipment is needed to lift the pipeline into the trench, and then the workers will install it. During installation, the pipeline itself is long and heavy, which is not convenient to move for fine-tuning. It requires the cooperation of lifting machinery and personnel above. The construction time is long and the construction efficiency is low, resulting in increased construction costs. Summary of the Invention

[0003] In order to overcome the shortcomings of the background technology, the present invention discloses a trench construction method for municipal pipeline engineering. The present invention forms a construction closed loop through preliminary preparation, construction site mapping, trench excavation and construction, trench backfilling and quality inspection and acceptance, so as to achieve the purpose of completing trench construction efficiently and safely.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0005] A method for constructing a trench for a municipal pipeline project comprises the following steps:

[0006] S1. Preliminary preparation: study and check the blueprints, conduct on-site surveys and mark above-ground and underground obstacles, and record the location and elevation of the reserved pipes for the existing sewage pipes;

[0007] S2. Survey and map the construction site, determine the pipeline center, check the elevation of the connection point to the existing pipeline, lay out the trenching edge, earth pile materials and boundaries, and the scope of temporary land use, measure the pipeline ground elevation and bury the grade plate, and set up clear signs;

[0008] S3. Trench excavation construction, using a backhoe excavator and manual labor to dig the trench, and setting up and using construction maintenance equipment;

[0009] S4, trench backfilling: after laying the municipal pipeline in the trench, use the construction and maintenance equipment to assist in backfilling with soil;

[0010] S5. Quality inspection and acceptance.

[0011] The aforementioned preliminary preparations should also include the preparation of a portable generator and a submersible pump. The portable generator can prevent sudden power outages during construction and the construction section that is without power needs electricity. The submersible pump can prevent the impact of groundwater and trenches being soaked by water on rainy days.

[0012] During the trench excavation, a slope is formed at the bottom of the trench to facilitate drainage. A temporary drainage ditch is set up beside the trench, and water collection wells are set up at intervals so that accumulated water can enter the water collection wells through the drainage ditch.

[0013] The construction and maintenance device includes a positioning plate arranged on the ground at the upper edge of the groove, a load-bearing frame provided above the positioning plate, a plastic film roll provided above the load-bearing frame, a slope protection frame provided on the side of the positioning plate close to the groove, the slope protection frame provided on the two inner walls of the groove, and the lower end of the slope protection frame provided in the two drainage ditches at the bottom of the groove.

[0014] The lower surface of the positioning plate is provided with a fixed shaft which is inserted into the ground. A slot is provided on one side of the positioning plate close to the groove. The upper surface of the positioning plate is provided with a fixed hole, and the lower end of the fixed hole is connected to the slot.

[0015] The supporting frame is composed of a base plate, a baffle, a fixed rod, a connecting shaft, an airbag and a support block. The lower surface of the base plate is hinged to the positioning plate near one end of the groove, and the support block is distributed on the lower surface of the base plate away from the end of the groove. The lower surface of the base plate is provided with an airbag, and the upper surface of the base plate is provided with a baffle near one end of the groove. Two fixed rods are symmetrically provided on the upper surface of the baffle, and a connecting shaft is provided between the two fixed rods. The two ends of the connecting shaft are respectively connected to the inner surfaces of the two fixed rods. A plastic film roll is put on the connecting shaft, and the plastic film is spread on the pile of soil of the supporting frame to keep the pile of soil dry and avoid dust.

[0016] The slope protection frame is composed of a support rod, a connecting rod and an insert block. At least two support rods are provided on the slope protection frame. The support rods abut against the inner wall of the groove. The upper end of the support rod is provided with an insert block, which is arranged in a corresponding slot. The insert block is provided with a lower surface thread hole that passes through the upper surface. The thread hole is arranged corresponding to the fixing hole. The insert block is connected to the positioning plate by a bolt. The bolt passes through the fixing hole and the thread hole, and the bolt is threadedly connected to the thread hole. The lower end of the support rod is arranged in the drainage ditch, and the lower end of the support rod is inserted into the soil layer at the bottom of the drainage ditch. Two connecting rods are provided between the adjacent two support rods of the slope protection frame, and a plastic film is laid on the lower slope protection frame to prevent rainwater or groundwater from directly eroding the inner wall of the groove, thereby preventing the soil layer in the groove from having too high a water content.

[0017] The two connecting rods are arranged in parallel, and the two ends of the connecting rods are respectively connected to the two adjacent support rods. A screw is provided on the two connecting rods, the upper end of the screw passes through the upper connecting rod, and the lower end of the screw passes through the lower connecting rod. Blocks are provided at the upper and lower ends of the screw. A sleeve is provided on the screw, and an internal thread is provided on the inner wall of the sleeve. The internal thread of the sleeve cooperates with the external thread of the screw. A supporting device is provided on the side of the sleeve, and a fixed shell is provided above the sleeve, and a turbine and a worm are provided in the fixed shell.

[0018] The fixed shell is arranged on the lower surface of the upper connecting rod, the screw passes through the fixed shell, the turbine is sleeved on the screw, the inner wall of the turbine is connected to the side of the screw, the worm is arranged on one side of the turbine, the worm and the turbine cooperate with each other, one end of the worm is rotatably connected to the inner wall of the fixed shell, and the other end of the worm passes through the opposite side of the fixed shell, and rotating the worm drives the screw to rotate.

[0019] The slope guardrails on both sides are provided with support devices, and the support devices on both sides are arranged on the bottom surface of the groove. The two support devices are symmetrically arranged. The support devices are composed of support rollers, rotating shafts, bearings and positioning rods. At least two support rollers are provided on the support device, and a rotating shaft is provided between two adjacent support rollers. The support rollers and the rotating shaft have the same axial axis. Bearings are provided on the side of the rotating shaft, and the bearings are sleeved on the rotating shaft. Positioning rods are provided on the side of the bearings. One end of the positioning rod is connected to the side of the bearing, and the other end of the positioning rod is hinged to the side of the adjacent sleeve. The sleeve moves up and down on the screw to drive the two support devices to move horizontally, and the distance between the two support devices is adjusted to facilitate the placement of the pipes in the installation groove.

[0020] The trench construction method for municipal pipeline projects described in the present invention is highly practical and very convenient to use. By setting up a slope protection frame, the inner wall of the trench can be effectively protected from being eroded by rainwater or groundwater, thereby preventing the water content of the soil layer in the trench from being too high; by setting up a load-bearing frame, it can prevent the soil piled at the edge of the trench from falling into the trench, thereby ensuring the construction quality, and protecting the personal safety of the trench construction workers, and can facilitate the backfilling of soil and improve work efficiency; through this support device, the laying and installation of pipelines in the trench are facilitated. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the position relationship of the present invention;

[0022] Figure 2 is a cross-sectional view of the positioning plate of the present invention;

[0023] Figure 3 is a cross-sectional view of the carrier frame of the present invention;

[0024] Figure 4 It is a schematic diagram of the three-dimensional structure of the slope protection frame of the present invention;

[0025] Figure 5This is a schematic diagram of the connection between the connecting rod and the lead screw of the present invention;

[0026] Figure 6 is a cross-sectional view of the support device of the present invention;

[0027] In the figure: 1. Ground; 2. Grooves; 3. Drainage ditch; 4. Slope protection frame; 5. Support device; 6. Carrying frame; 7. Plastic film roll; 8. Positioning plate; 9. Fixed shaft; 10. Slot; 11. Fixed hole; 12. Bottom plate; 13. Baffle; 14. Fixed rod; 15. Connecting shaft; 16. Airbag; 17. Support block; 18. Support rod; 19. Connecting rod; 20. Insert block; 21. Threaded hole; 22. Lead screw; 23. Block; 24. Fixed housing; 25. Turbine; 26. Worm; 27. Sleeve; 28. Support roller; 29. ​​Rotating shaft; 30. Bearing; 31. Positioning rod. DETAILED DESCRIPTION

[0028] The present invention can be explained in detail by the following examples, the purpose of which is to disclose the present invention and to protect all technical improvements within the scope of the present invention.

[0029] Combined with attachment Figures 1 to 6 A method for constructing a trench for a municipal pipeline project comprises the following steps:

[0030] S1. Preliminary preparation: study and check the blueprints, conduct on-site surveys and mark above-ground and underground obstacles, and record the location and elevation of the reserved pipes for the existing sewage pipes;

[0031] S2. Survey and map the construction site, determine the pipeline center, check the elevation of the connection point to the existing pipeline, lay out the trenching edge, earth pile materials and boundaries, and the scope of temporary land use, measure the pipeline ground elevation and bury the grade plate, and set up clear signs;

[0032] S3. Trench excavation construction, using a backhoe excavator and manual labor to dig the trench, and setting up and using construction maintenance equipment;

[0033] S4, trench backfilling: after laying the municipal pipeline in the trench, use the construction and maintenance equipment to assist in backfilling with soil;

[0034] S5. Quality inspection and acceptance.

[0035] The aforementioned preliminary preparations should also include the preparation of a portable generator and a submersible pump. The portable generator can prevent sudden power outages during construction and the construction section that is without power needs electricity. The submersible pump can prevent the impact of groundwater and trenches being soaked by water on rainy days.

[0036] During the trench excavation, a slope is formed at the bottom of the trench to facilitate drainage. A temporary drainage ditch is set up beside the trench, and water collection wells are set up at intervals so that accumulated water can enter the water collection wells through the drainage ditch.

[0037] The construction and maintenance device includes a positioning plate 8 arranged on the ground 1 at the upper edge of the groove 2, a supporting frame 6 is provided above the positioning plate 8, a plastic film roll 7 is provided above the supporting frame 6, and a slope protection frame 4 is provided on the side of the positioning plate 8 close to the groove 2. The slope protection frame 4 is arranged on the two inner walls of the groove 2, and the lower end of the slope protection frame 4 is arranged in the two drainage ditches 3 at the bottom of the groove 2.

[0038] A fixing shaft 9 is distributed on the lower surface of the positioning plate 8, and the fixing shaft 9 is inserted into the ground 1. A slot 10 is distributed on the side of the positioning plate 8 close to the groove 2. A fixing hole 11 is distributed on the upper surface of the positioning plate 8, and the lower end of the fixing hole 11 is connected to the slot 10.

[0039] The carrier frame 6 is composed of a base plate 12, a baffle 13, a fixed rod 14, a connecting shaft 15, an airbag 16 and a support block 17. The lower surface of the base plate 12 is hinged to the positioning plate 8 near one end of the groove 2, and a support block 17 is distributed on the lower surface of the base plate 12 away from the end of the groove 2. The lower surface of the base plate 12 is provided with an airbag 16, and the upper surface of the base plate 12 is provided with a baffle 13 near one end of the groove 2. Two fixed rods 14 are symmetrically provided on the upper surface of the baffle 13, and a connecting shaft 15 is provided between the two fixed rods 14. The two ends of the connecting shaft 15 are respectively connected to the inner surfaces of the two fixed rods 14. The plastic film roll 7 is sleeved on the connecting shaft 15, and the plastic film is spread on the pile of soil of the carrier frame 6 to keep the pile of soil dry and avoid dust.

[0040] The slope protection frame 4 is composed of a support rod 18, a connecting rod 19 and an insert block 20. The slope protection frame 4 is provided with at least two support rods 18, which abut against the inner wall of the groove 2. The upper end of the support rod 18 is provided with an insert block 20, which is arranged in the corresponding slot 10. The insert block 20 is provided with a lower surface thread hole 21 that passes through the upper surface. The thread hole 21 is corresponding to the fixing hole 11. The insert block 20 is connected to the positioning plate 8 by a bolt, which passes through the fixing hole 11 and the thread hole 21, and the bolt is threadedly connected to the thread hole 21. The lower end of the support rod 18 is arranged in the drainage ditch 3, and the lower end of the support rod 18 is inserted in the soil layer at the bottom of the drainage ditch 3. Two connecting rods 19 are provided between the adjacent two support rods 18 of the slope protection frame 4, and a plastic film is laid on the lower slope protection frame 4 to prevent rainwater or groundwater from directly scouring the inner wall of the groove 2 and to prevent the soil layer in the groove 2 from having too high a water content.

[0041] The two connecting rods 19 are arranged in parallel, and the two ends of the connecting rod 19 are respectively connected to the two adjacent support rods 18. A screw 22 is provided on the two connecting rods 19. The upper end of the screw 22 passes through the upper connecting rod 19, and the lower end of the screw 22 passes through the lower connecting rod 19. The upper and lower ends of the screw 22 are both provided with a block 23. A sleeve 27 is provided on the screw 22, and an internal thread is provided on the inner wall of the sleeve 27. The internal thread of the sleeve 27 cooperates with the external thread of the screw 22. A supporting device 5 is provided on the side of the sleeve 27, and a fixed shell 24 is provided above the sleeve 27. A turbine 25 and a worm 26 are provided in the fixed shell 24.

[0042] The fixed housing 24 is arranged on the lower surface of the upper connecting rod 19, the screw 22 passes through the fixed housing 24, the turbine 25 is sleeved on the screw 22, the inner wall of the turbine 25 is connected to the side of the screw 22, and the worm 26 is arranged on one side of the turbine 25. The worm 26 and the turbine 25 cooperate with each other. One end of the worm 26 is rotatably connected to the inner wall of the fixed housing 24, and the other end of the worm 26 passes through the opposite side of the fixed housing 24. Rotating the worm 26 drives the screw 22 to rotate.

[0043] The slope guard frames 4 on both sides are provided with support devices 5, and the support devices 5 on both sides are arranged on the bottom surface of the groove 2. The two support devices 5 are symmetrically arranged. The support device 5 is composed of a support roller 28, a rotating shaft 29, a bearing 30 and a positioning rod 31. At least two support rollers 28 are provided on the support device 5, and a rotating shaft 29 is provided between two adjacent support rollers 28. The support roller 28 and the rotating shaft 29 have the same axial axis. A bearing 30 is provided on the side of the rotating shaft 29, and the bearing 30 is sleeved on the rotating shaft 29. The side of the bearing 30 is provided with a positioning rod 31, one end of the positioning rod 31 is connected to the side of the bearing 30, and the other end of the positioning rod 31 is hinged to the side of the adjacent sleeve 27. The sleeve 27 moves up and down on the screw 22 to drive the two support devices 5 to move horizontally, and adjust the distance between the two support devices 5 to facilitate the placement and installation of the pipes in the groove 2.

[0044] The embodiment of the trench construction method for municipal pipeline engineering first studies and checks the drawings, conducts on-site surveys and marks obstacles above and below the ground, records the position and elevation of the reserved pipes for the existing sewage pipes, then measures the center of the pipeline, checks the elevation of the connection joints to the original pipelines, lays out the trenching edges, earth-piling materials and boundaries and the scope of temporary land use, measures the ground elevation of the pipelines and the buried slope plates, sets clear markings, and lays out the lines in the construction area to facilitate construction. Before excavation, the positioning plate 8 is installed at the edge of the trench 2, the fixed shaft 9 is inserted into the soil layer below, and the upper support frames 6 are arranged side by side. The upper edge of the trench 2 is then dug with a backhoe and manual labor. The excavator evenly piles the excavated soil on top of the bottom plate 12 and presses the bottom plate 12 onto the ground 1. After the soil is piled on the bottom plate 12, the plastic film roll 7 above the carrier 6 is pulled to cover the soil to keep the soil dry and avoid dust. The trench 2 is manually leveled and drain ditches 3 are dug on both sides of the bottom of the trench 2. The slope protection frame 4 is installed on the positioning plate 8. First, one end of the support rod 18 is inserted into the soil layer at the bottom of the drainage ditch 3, and the upper plug block 20 is aligned with the slot 10, and then the plug block 20 is inserted into the slot 10 and fixed with bolts so that the support rod 18 is close to the inner wall of the groove 2, and then the plastic film roll 7 is covered on the slope protection frame 4. Rainwater falls on the plastic film and slides into the drainage ditch 3 with the plastic film, avoiding rainwater or groundwater from directly washing on the inner wall of the groove 2 and avoiding excessive moisture content in the soil layer in the groove 2. When it is necessary to lay the pipeline, first mark the pipeline laying position at the bottom of the groove 2 with a line, retract the plastic film on the slope protection frame 4, install the support device 5 on the sleeve 27, rotate the worm 26 to adjust the height of the sleeve 27, and thereby adjust the position of the support roller 28 below so that the support devices 5 on both sides are The two supporting devices 5 are parallel and stuck together, and the supporting rollers 28 of the two supporting devices 5 are located on both sides of the pipeline laying line. After the adjustment is completed, the pipeline is hoisted on the supporting rollers 28 of the supporting devices 5 on both sides, and the worm 26 is rotated in the opposite direction to make the two supporting devices 5 move away from each other in the opposite directions, so that the upper pipeline slowly falls to the bottom of the groove 2 to complete the pipeline laying. After the pipeline is laid, the plastic film above the soil pile is put away, and air is inflated into the airbag 16. The expansion of the airbag 16 causes one end of the bottom plate 12 to rise, so that the soil pile on the bottom plate 12 slides from the baffle 13 into the groove 2, quickly completing the backfill of the soil pile, and then compacting the soil pile, and finally conducting quality inspection and acceptance.

[0045] The parts of the invention that are not described in detail are prior art. Although the present invention is specifically demonstrated and introduced in conjunction with the preferred embodiments, there are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. However, those skilled in the art should understand that various changes can be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, and all of these are within the scope of protection of the present invention.

Claims

1. A trench construction method for municipal pipeline engineering, characterized by: The following steps are involved: S1. Preliminary preparation: study and check the blueprints, conduct on-site surveys and mark above-ground and underground obstacles, and record the location and elevation of the reserved pipes for the existing sewage pipes; S2. Survey and map the construction site, determine the pipeline center, check the elevation of the connection point to the existing pipeline, lay out the trenching edge, earth pile materials and boundaries, and the scope of temporary land use, measure the pipeline ground elevation and bury the grade plate, and set up clear signs; S3. Trench excavation construction, using a backhoe excavator and manual labor to dig the trench, and setting up a construction and maintenance device; the construction and maintenance device includes a positioning plate (8) set on the ground (1) at the upper edge of the trench (2), a bearing frame (6) is set above the positioning plate (8), a plastic film roll (7) is set above the bearing frame (6), a slope protection frame (4) is set on one side of the positioning plate (8) close to the trench (2), the slope protection frame (4) is set on the two inner walls of the trench (2), and the lower end of the slope protection frame (4) is set at the bottom of the trench (2). In the two drainage ditches (3); the carrier (6) is composed of a bottom plate (12), a baffle (13), a fixing rod (14), a connecting shaft (15), an airbag (16) and a support block (17). The lower surface of the bottom plate (12) is close to the end of the groove (2) and is hinged to the positioning plate (8). The lower surface of the bottom plate (12) is away from the end of the groove (2) and is provided with a support block (17). The lower surface of the bottom plate (12) is provided with an airbag (16). The upper surface of the bottom plate (12) is close to the end of the groove (2) and is provided with a baffle (13). The baffle (13) The upper surface of the slope protection frame (4) is symmetrically provided with two fixing rods (14), a connecting shaft (15) is provided between the two fixing rods (14), the two ends of the connecting shaft (15) are respectively connected to the inner surface of the two fixing rods (14), and the plastic film roll (7) is sleeved on the connecting shaft (15); the slope protection frame (4) is composed of a support rod (18), a connecting rod (19) and an insert (20), and the slope protection frame (4) is provided with at least two support rods (18), the support rod (18) is in contact with the inner wall of the groove (2), and the upper end of the support rod (18) is provided with an insert ( 20), the plug (20) is arranged in the corresponding slot (10), the plug (20) is provided with a lower surface thread hole (21) penetrating the upper surface, the thread hole (21) is arranged corresponding to the fixing hole (11), the plug (20) is connected to the positioning plate (8) by a bolt, the bolt passes through the fixing hole (11) and the thread hole (21), the bolt is threadedly connected to the thread hole (21), the lower end of the support rod (18) is arranged in the drainage ditch (3), and two connecting rods (19) are provided between two adjacent support rods (18) of the slope protection frame (4); S4, trench backfilling: after laying the municipal pipeline in the trench, use the construction and maintenance equipment to assist in backfilling with soil; S5. Quality inspection and acceptance.

2. The trench construction method for municipal pipeline engineering according to claim 1, characterized in that: The aforementioned preliminary preparations should also include the preparation of a portable generator and a submersible pump. The portable generator can prevent sudden power outages during construction and the construction section that is without power needs electricity. The submersible pump can prevent the impact of groundwater and trenches being soaked by water on rainy days.

3. The trench construction method for municipal pipeline engineering according to claim 1, characterized in that: During the trench excavation, a slope is formed at the bottom of the trench to facilitate drainage. A temporary drainage ditch is set up beside the trench, and water collection wells are set up at intervals so that accumulated water can enter the water collection wells through the drainage ditch.

4. The method for constructing a trench for a municipal pipeline project according to claim 1, wherein: A fixing shaft (9) is distributed on the lower surface of the positioning plate (8), and the fixing shaft (9) is inserted into the ground (1). A slot (10) is distributed on one side of the positioning plate (8) close to the groove (2). A fixing hole (11) is distributed on the upper surface of the positioning plate (8), and the lower end of the fixing hole (11) is communicated with the slot (10).

5. The method for constructing a trench for a municipal pipeline project according to claim 1, wherein: Two connecting rods (19) are arranged in parallel, and the two ends of the connecting rod (19) are respectively connected to the two adjacent support rods (18). A lead screw (22) is provided on the two connecting rods (19), the upper end of the lead screw (22) passes through the upper connecting rod (19), and the lower end of the lead screw (22) passes through the lower connecting rod (19). The upper and lower ends of the lead screw (22) are both provided with a clamping block (23). A sleeve (27) is provided on the lead screw (22), and an internal thread is provided on the inner wall of the sleeve (27). The internal thread of the sleeve (27) cooperates with the external thread of the lead screw (22). A supporting device (5) is provided on the side of the sleeve (27), and a fixed housing (24) is provided above the sleeve (27). A turbine (25) and a worm (26) are provided in the fixed housing (24).

6. The method for constructing a trench for a municipal pipeline project according to claim 5, wherein: The fixed housing (24) is arranged on the lower surface of the upper connecting rod (19), the screw (22) passes through the fixed housing (24), the turbine (25) is sleeved on the screw (22), the inner wall of the turbine (25) is connected to the side of the screw (22), the worm (26) is arranged on one side of the turbine (25), the worm (26) and the turbine (25) cooperate with each other, one end of the worm (26) is rotatably connected to the inner wall of the fixed housing (24), and the other end of the worm (26) passes through the opposite side of the fixed housing (24).

7. The method for constructing a trench for a municipal pipeline project according to claim 5, wherein: The slope protection frames (4) on both sides are provided with support devices (5), the support devices (5) on both sides are arranged on the bottom surface of the groove (2), the two support devices (5) are symmetrically arranged, the support device (5) is composed of a support roller (28), a rotating shaft (29), a bearing (30) and a positioning rod (31), at least two support rollers (28) are provided on the support device (5), a rotating shaft (29) is provided between two adjacent support rollers (28), the support rollers (28) and the rotating shaft (29) are coaxial, a bearing (30) is provided on the side of the rotating shaft (29), the bearing (30) is sleeved on the rotating shaft (29), and a positioning rod (31) is provided on the side of the bearing (30), one end of the positioning rod (31) is connected to the side of the bearing (30), and the other end of the positioning rod (31) is hinged to the side of the adjacent sleeve (27).

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