Municipal road rapid drainage structure

Abstract

The present application relates to a kind of municipal road rapid drainage structure, it includes well lid, well lid includes fixed ring, fixed cover, rotating cover and trash frame, fixed cover is connected in fixed ring, several drainage gaps are opened in fixed cover, rotating cover is rotatably connected in fixed ring, rotating cover is connected with the limiting piece that the rotation angle of rotating cover is limited, fixed cover and rotating cover are all opened with several drainage holes, trash frame is connected with several on rotating cover, trash frame is one-to-one with drainage gap, fixed cover is provided with the drive piece of the rotation of driving rotating cover, drive piece is connected with rotating cover, trash frame includes fixed frame and trash column, trash column is connected with several on fixed frame, gap is left between adjacent two trash columns, fixed frame is connected on rotating cover.The present application has the effect of reducing well lid place water accumulation phenomenon.

Description

Technical Field

[0001] This invention relates to the field of municipal road drainage technology, and in particular to a rapid drainage structure for municipal roads. Background Technology

[0002] Municipal drainage pipes refer to rainwater and sewage pipes under municipal roads. They are widely used in urban roads and are mainly used to discharge rainwater into nearby rivers or sewage treatment plants, thereby greatly alleviating the traffic obstruction caused by road flooding.

[0003] Workers often install manhole covers at the inlet of drainage pipes to both assist drainage and cover the inlet of the pipes, thereby improving the safety of municipal roads.

[0004] During rainy days, rainwater on the road surface enters underground drainage pipes through the drainage holes on manhole covers. However, during heavy rain, the amount of rainwater on the road surface increases, and there is often a lot of water accumulating at the manhole covers along the roadside. The main reason is that the number of drainage holes on the manhole covers is small and the diameter is small, which means that the drainage capacity of the manhole covers cannot keep up with the water inflow. In addition, garbage on the road surface is moved to the surface of the manhole covers with the rainwater, blocking the drainage holes on the manhole covers and further worsening the drainage situation of municipal roads. Summary of the Invention

[0005] To reduce water accumulation at manhole covers, this application provides a rapid drainage structure for municipal roads.

[0006] This application provides a rapid drainage structure for municipal roads using the following technical solution:

[0007] A rapid drainage structure for municipal roads includes a manhole cover, which comprises a fixed ring, a fixed cover plate, a rotating cover plate, and a debris-blocking frame. The fixed cover plate is connected to the fixed ring and has several drainage openings. The rotating cover plate is rotatably connected to the fixed ring and has a limiting member connected to it to restrict its rotation angle. Both the fixed cover plate and the rotating cover plate have several drainage holes. Several debris-blocking frames are connected to the rotating cover plate, and each debris-blocking frame corresponds to one of the drainage openings. The fixed cover plate is provided with a driving member that drives the rotating cover plate to rotate, and the driving member is connected to the rotating cover plate. Each debris-blocking frame includes a fixed frame and debris-blocking columns, and several debris-blocking columns are connected to the fixed frame with a gap between adjacent columns. The fixed frame is connected to the rotating cover plate. During normal drainage, the rotating cover plate blocks the drainage openings; during emergency drainage, the debris-blocking frames block the drainage openings.

[0008] By adopting the above technical solution, during normal drainage, workers use the drainage holes on the fixed and rotating covers to drain water. When rainfall increases, workers use a drive mechanism to rotate the cover, and then use a limiting mechanism to restrict the rotation angle of the rotating cover. At this time, the debris-blocking frame covers the drainage gap, achieving the effect of emergency drainage. Workers use the drainage holes to deal with rainwater with less rainfall, and use the debris-blocking frame to discharge rainwater with more rainfall. The debris-blocking frame drains water through the gaps between the debris-blocking columns, making the drainage capacity of the debris-blocking frame greater than that of the drainage holes, so that more rainwater is discharged into the underground drainage pipe per unit time. At the same time, workers use the debris-blocking frame to intercept larger pieces of garbage on the road surface, reducing the possibility of garbage clogging the underground drainage pipe, thereby reducing water accumulation at the manhole cover.

[0009] Optionally, a gap is provided between the debris-blocking frame and the fixed cover plate, and several debris-limiting columns are connected to the debris-blocking frame, with the debris-limiting columns located within the debris-blocking gap.

[0010] By adopting the above technical solutions, staff increased the drainage space of the manhole cover during normal drainage by utilizing the gaps in the debris barrier, further improving the drainage capacity of the manhole cover during normal drainage. They also used debris-limiting bollards to intercept garbage on the road surface, further reducing the possibility of water accumulation in the manhole cover.

[0011] Optionally, the limiting element is a sliding block, and the fixed cover plate has a limiting arc groove, the center of which is located on the axis of the fixed ring, and the limiting element is slidably fitted within the limiting arc groove.

[0012] By adopting the above technical solution, the staff used the limiting arc groove to limit the sliding stroke of the sliding component, thereby limiting the rotation angle of the rotating cover plate, so that the debris barrier frame can smoothly cover the drainage gap and improve the rotation accuracy of the debris barrier frame.

[0013] Optionally, both the rotating cover and the debris-blocking frame are connected to a rotating arc strip at their arc edges. The bottom end of the fixed ring has a sliding ring groove, and the bottom end of the fixed ring is also connected to a sealing ring. The rotating arc strip is slidably fitted in the sliding ring groove and is located between the fixed ring and the sealing ring.

[0014] By adopting the above technical solution, the staff used the sealing ring and sliding groove to limit the rotation direction of the rotating arc strip, making the rotation of the rotating cover and the debris-blocking frame more stable.

[0015] Optionally, a settling assembly is provided at the bottom end of the fixed ring. The settling assembly includes a settling cylinder, a baffle, and a diversion plate. The settling cylinder is connected to the bottom end of the fixed ring. The baffle is connected to the inner bottom wall of the settling cylinder. The baffle divides the interior of the settling cylinder into a settling chamber and a drainage chamber. A drainage channel is opened at the bottom of the drainage chamber. The diversion plate is connected inside the settling cylinder and is inclined. The lowest point of the diversion plate is located above the settling chamber.

[0016] By adopting the above technical solution, rainwater contains a significant amount of dust. To further reduce siltation in underground drainage pipes, it is necessary to separate the dust and fine debris. During settling, workers use diversion plates to guide all rainwater into the settling chamber. As the amount of rainwater in the settling chamber increases, the dust in the rainwater settles at the bottom of the chamber. The rainwater then overflows from the baffle and enters the underground drainage pipe through the drainage channel, thus achieving the effect of settling dust.

[0017] Optionally, the fixing ring is provided with an installation component, which includes an installation ring, a rotating ring, and a limiting block. The rotating ring is rotatably connected to the top end of the installation ring, the limiting block is connected to the inner wall of the installation ring, the fixing ring is threaded into the rotating ring and plugged into the installation ring, and the surface of the fixing ring has a limiting groove, which is vertically arranged, and the limiting block is slidably engaged in the limiting groove.

[0018] By adopting the above technical solution, when installing the manhole cover, the worker places the fixing ring on the rotating ring and restricts the fixing ring. The rotating ring is then rotated to lower the fixing ring, allowing the restricting block to smoothly enter the restricting groove. The fixing ring is then released, and the rotating ring is rotated again to lower the fixing ring until the fixing cover plate is flush with the rotating ring, thus achieving the effect of installing the manhole cover. When removing the manhole cover, the worker rotates the rotating ring in the opposite direction to raise the fixing ring until the fixing ring disengages from the rotating ring, at which point the manhole cover can be removed.

[0019] Optionally, a water pressure sensor and a controller are provided on the rotating cover plate. The detection end of the water pressure sensor passes through the rotating cover plate. The driving component is a drive motor. Both the driving component and the water pressure sensor are electrically connected to the controller.

[0020] By adopting the above technical solution, staff use a water pressure sensor to detect the water pressure on the rotating cover. When the rainfall is heavy, the amount of rainwater increases, the drainage speed of the manhole cover decreases, and the water accumulation on the surface of the manhole cover increases, causing the water pressure on the surface of the fixed cover to rise slowly. When the water pressure on the fixed cover reaches a specific value, the water pressure sensor sends an electrical signal to the controller, causing the controller to start the drive component and rotate the cover until the debris frame covers the drainage gap, thereby increasing the drainage capacity of the manhole cover. This achieves the effect of automatically adjusting the drainage capacity of the manhole cover when the rainfall is heavy.

[0021] Optionally, both the fixed cover plate and the rotating cover plate have several anti-slip ridges on their surfaces.

[0022] By adopting the above technical solution, the anti-slip ridges are used to increase the friction on the surfaces of the fixed cover plate and the rotating cover plate, reducing the possibility of pedestrians slipping on the fixed cover plate or the rotating cover plate.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. During normal drainage, workers use the drainage holes on the fixed and rotating covers to drain water. When rainfall increases, workers use a drive mechanism to rotate the cover, and then use a limiting mechanism to restrict the rotation angle of the rotating cover. At this time, the debris-blocking frame covers the drainage gap, achieving the effect of emergency drainage. Workers use the drainage holes to deal with rainwater with less rainfall, and use the debris-blocking frame to discharge rainwater with more rainfall. The debris-blocking frame drains water through the gaps between the debris-blocking columns, making the drainage capacity of the debris-blocking frame greater than that of the drainage holes, so that more rainwater is discharged into the underground drainage pipe per unit time. At the same time, workers use the debris-blocking frame to intercept larger pieces of garbage on the road surface, reducing the possibility of garbage clogging the underground drainage pipe, thereby reducing water accumulation at the manhole cover.

[0025] 2. When installing the manhole cover, the worker places the fixing ring on the rotating ring and restricts the fixing ring. The rotating ring is then rotated to lower the fixing ring, allowing the restricting block to smoothly enter the restricting groove. The fixing ring is then released, and the rotating ring is continued to be rotated to lower the fixing ring until the fixing cover is flush with the rotating ring, thus achieving the effect of installing the manhole cover. When removing the manhole cover, the worker rotates the rotating ring in the opposite direction to raise the fixing ring until the fixing ring disengages from the rotating ring, at which point the manhole cover can be removed. Attached Figure Description

[0026] Figure 1 This is a rendering of the rainwater interception facility on the road surface in the embodiments of this application.

[0027] Figure 2 This is a schematic diagram of the overall structure of the rapid drainage structure for municipal roads in this application embodiment.

[0028] Figure 3 This is an exploded view used to illustrate the structure of the manhole cover in the embodiments of this application.

[0029] Figure 4 This is a diagram showing the emergency drainage status of the manhole cover in an embodiment of this application.

[0030] Figure 5 This is a bottom view of the rotating cover plate in an embodiment of this application.

[0031] Figure 6This is a top view of the rainwater interception facility in the embodiments of this application.

[0032] Figure 7 yes Figure 6 Sectional view of AA.

[0033] Figure 8 yes Figure 7 Enlarged view of section B in the middle.

[0034] Explanation of reference numerals in the attached drawings: 1. Manhole cover; 11. Fixing ring; 111. Sliding ring groove; 112. Sealing ring; 113. Restricting groove; 12. Fixing cover plate; 121. Drainage notch; 122. Restricting arc groove; 13. Rotating cover plate; 131. Pollution-limiting column; 14. Pollution-blocking frame; 141. Fixing frame; 142. Pollution-blocking column; 2. Drainage hole; 3. Rotating arc strip; 4. Driving component; 41. Water pressure sensor; 42. Controller; 5. Restricting component; 6. Anti-slip ridge; 7. Settling assembly; 71. Settling cylinder; 711. Settling chamber; 712. Drainage chamber; 713. Drainage channel; 72. Baffle; 73. Drainage plate; 8. Installation assembly; 81. Installation ring; 82. Rotating ring; 821. Rotating groove; 83. Restricting block. Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0036] This application discloses a rapid drainage structure for municipal roads. (Refer to...) Figure 1 , Figure 2 and Figure 3 The municipal road rapid drainage structure includes a manhole cover 1, which includes a fixing ring 11, a fixing cover plate 12, a rotating cover plate 13, and a debris-blocking frame 14. The fixing cover plate 12 is fixedly connected inside the fixing ring 11, and the fixing cover plate 12 has several drainage gaps 121. The drainage gaps 121 are arranged in a fan shape. In this embodiment, two drainage gaps 121 are arranged symmetrically about the axis of the fixing ring 11.

[0037] Reference Figure 2 and Figure 3A rotating cover plate 13 is positioned below a fixed cover plate 12. Both the rotating cover plate 13 and the fixed cover plate 12 have several drainage holes 2. A debris-blocking frame 14 is fixedly connected to the rotating cover plate 13 at a position corresponding to the drainage gap 121. The debris-blocking frame 14 includes a fixed frame 141 and debris-blocking columns 142. Several debris-blocking columns 142 are fixedly connected to the fixed frame 141, with a gap between adjacent debris-blocking columns 142. Rotating arc strips 3 are fixedly connected to the edges of both the rotating cover plate 13 and the debris-blocking frame 14. A sliding ring groove 111 is opened at the bottom end of the fixed ring 11, and the rotating arc strip 3 slides within the sliding ring groove 111. A sealing ring 112 is fixedly connected to the bottom end of the fixed ring 11, and the rotating arc strip 3 is located between the sliding ring groove 111 and the sealing ring 112. A debris-blocking gap is left between the rotating cover plate 13 and the fixed cover plate 12, and several debris-limiting columns 131 are fixedly connected to the fixed frame 141. The debris-blocking gap is used to increase the drainage capacity of the manhole cover 1, and the debris-limiting column 131 is used to assist in intercepting garbage.

[0038] Reference Figure 3 , Figure 4 and Figure 5 A drive component 4, which is a drive motor, is provided on the fixed cover plate 12. The rotating cover plate 13 is fixedly connected to the output shaft of the drive component 4, and a waterproof plate is provided on the surface of the drive component 4. A water pressure sensor 41 and a controller 42 are installed on the bottom wall of the rotating cover plate 13. The detection end of the water pressure sensor 41 passes through the rotating cover plate 13 and is flush with the surface of the rotating cover plate 13. Both the drive component 4 and the water pressure sensor 41 are electrically connected to the controller 42.

[0039] Reference Figure 2 , Figure 4 and Figure 5 During normal rain, the rotating cover 13 blocks the drainage gap 121, and the staff uses the drainage hole 2 and the debris-blocking gap to drain the rainwater. When the rainfall increases, more rainwater flows into the manhole cover 1, and the drainage capacity of the drainage hole 2 and the debris-blocking gap cannot meet the inflow of rainwater, causing more water to accumulate at the rotating cover 13 and increasing the water pressure at the rotating cover 13. When a specific value is reached, the water pressure sensor 41 sends an electrical signal to the controller 42, causing the controller 42 to start the drive component 4, which drives the rotating cover 13 to rotate until the debris-blocking frame 14 covers the drainage gap 121, thereby increasing the drainage capacity of the manhole cover 1 and achieving the effect of automatically adjusting the drainage capacity of the manhole cover 1.

[0040] Reference Figure 2To improve the rotational accuracy of the rotating cover plate 13, a limiting member 5 is fixedly connected to the rotating cover plate 13. The limiting member 5 is a sliding block, and two limiting members 5 are provided. A limiting arc groove 122 is opened on the fixed cover plate 12 at the position corresponding to the limiting member 5. The axis of the limiting arc groove 122 is on the same straight line as the axis of the fixed ring 11. The limiting member 5 slides within the limiting arc groove 122. The limiting arc groove 122 is used to limit the movement stroke of the limiting member 5.

[0041] Reference Figure 1 In addition, in order to reduce the possibility of pedestrians slipping on the fixed cover plate 12 or the rotating cover plate 13, a number of anti-slip ridges 6 are fixedly connected to both the fixed cover plate 12 and the rotating cover plate 13. The anti-slip ridges 6 are used to increase the surface friction of the fixed cover plate 12 and the rotating cover plate 13.

[0042] Reference Figure 6 , Figure 7 and Figure 8 A settling assembly 7 is provided below the fixing ring 11. The settling assembly 7 includes a settling cylinder 71, a baffle 72, and a drainage plate 73. The settling cylinder 71 is fixedly connected to the bottom wall of the sealing ring 112, and the top wall of the settling cylinder 71 is open. The baffle 72 is fixedly connected to the inner bottom wall of the settling cylinder 71, and the baffle 72 divides the interior of the settling cylinder 71 into a settling chamber 711 and a drainage chamber 712. A drainage channel 713 is opened on the bottom wall of the drainage chamber 712. The drainage plate 73 is fixedly connected inside the settling cylinder 71, and the drainage plate 73 is inclined, with the lowest point of the drainage plate 73 located above the settling chamber 711.

[0043] During settling, rainwater discharged from manhole cover 1 flows into settling chamber 711 through diversion plate 73. As the amount of rainwater in settling chamber 711 increases, the dust in the rainwater settles at the bottom of settling chamber 711. The rainwater then overflows from baffle 72 and enters underground drainage pipe through drainage channel 713, thus achieving the effect of settling dust.

[0044] Reference Figure 2 and Figure 8 An installation component 8 is provided on the outer side of the fixing ring 11. The installation component 8 includes an installation ring 81, a rotating ring 82, and a limiting block 83. The installation ring 81 is installed on the road at the inlet end corresponding to the underground drainage pipe. The rotating ring 82 is rotatably connected to the installation ring 81. The rotating ring 82 has several rotating grooves 821, which are used to facilitate workers to rotate the rotating ring 82 using tools. The limiting block 83 is fixedly connected to the installation ring 81. The fixing ring 11 is located inside the rotating ring 82. The fixing ring 11 is threaded to the rotating ring 82 and plugged into the installation ring 81. The fixing ring 11 has a limiting groove 113 at the position corresponding to the limiting block 83, and the limiting block 83 is slidably fitted in the limiting groove 113.

[0045] When installing manhole cover 1, the worker places the fixing ring 11 on the rotating ring 82 and restricts the fixing ring 11. Using a tool, the worker inserts the fixing ring 11 into the rotating groove 821 and rotates the rotating ring 82 to lower the fixing ring 11, allowing the restricting block 83 to smoothly enter the restricting groove 113. Then, the worker releases the fixing ring 11 and continues to rotate the rotating ring 82 until the fixing cover plate 12 is flush with the rotating ring 82, thus achieving the effect of installing manhole cover 1. When removing manhole cover 1, the worker rotates the rotating ring 82 in the opposite direction to raise the fixing ring 11 until the fixing ring 11 is disengaged from the rotating ring 82, at which point the manhole cover 1 can be removed.

[0046] The implementation principle of a rapid drainage structure for municipal roads according to this application embodiment is as follows: During normal rainfall, the rotating cover plate 13 blocks the drainage gap 121, and workers use the drainage hole 2 and the debris-blocking gap to discharge rainwater. When the rainfall increases, more rainwater flows into the manhole cover 1, and the drainage capacity of the drainage hole 2 and the debris-blocking gap cannot meet the inflow of rainwater, causing the water accumulation at the rotating cover plate 13 to increase, and the water pressure at the rotating cover plate 13 to increase until a specific value is reached. At this point, the water pressure sensor 41 sends an electrical signal to the controller 42, causing the controller 42 to control the drive component 4 to start. The rotating cover plate 13 is rotated until the debris frame 14 covers the drainage gap 121, aligning the drainage holes 2 on the fixed cover plate 12 and the rotating cover plate 13, thereby increasing the drainage capacity of the manhole cover 1 and automatically adjusting the drainage capacity of the manhole cover 1. At the same time, rainwater enters the settling chamber 711 along the diversion plate 73. As the amount of rainwater in the settling chamber 711 increases, the dust in the rainwater will settle at the bottom of the settling chamber 711. The rainwater then overflows from the baffle 72 and enters the underground drainage pipe through the drainage channel 713, achieving the effect of settling dust.

[0047] Workers utilize the drainage hole 2 and the gap between the debris barriers to handle light rain, the debris barrier frame 14 to discharge heavier rain, and the gaps between the debris barrier columns 142 to drain water. This ensures that the drainage capacity of the debris barrier frame 14 is greater than that of the drainage hole 2 and the gap between the debris barriers, allowing more rainwater to be discharged into the settling chamber 711 per unit time, and then from the settling chamber 711 into the underground drainage pipe. In addition, workers use the debris barrier columns 142 and the debris-limiting columns 131 to intercept larger pieces of garbage on the road surface, reducing the possibility of garbage clogging the underground drainage pipe. Furthermore, the garbage is concentrated in the debris barrier frame 14, making it easier for cleaners to clean, thereby reducing water accumulation at the manhole cover 1.

[0048] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A municipal road rapid drainage structure, characterized in that: The utility model relates to a well lid (1) including fixed ring (11), fixed cover plate (12), rotating cover plate (13) and trash rack (14), the fixed cover plate (12) is connected in the fixed ring (11), a plurality of drainage gaps (121) are opened on the fixed cover plate (12), the rotating cover plate (13) is rotatably connected in the fixed ring (11), the rotating cover plate (13) is connected with the limiting piece (5) of the rotating angle of the rotating cover plate (13) is limited, a plurality of drainage holes (2) are opened on the fixed cover plate (12) and the rotating cover plate (13), the trash rack (14) is connected on the rotating cover plate (13) a plurality of, the trash rack (14) with the drainage gap (121) one to one, the fixed cover plate (12) is provided with the drive piece (4) of the rotating cover plate (13) is driven, the drive piece (4) is connected with the rotating cover plate (13), the trash rack (14) includes fixed frame (141) and trash column (142), the trash column (142) is connected on the fixed frame (141) a plurality of, and the gap is left between adjacent two trash columns (142), the fixed frame (141) is connected on the rotating cover plate (13), when normal drainage, the rotating cover plate (13) blocks the drainage gap (121), when emergency drainage, the trash rack (14) blocks the drainage gap (121);The bottom of fixed ring (11) is provided with settlement assembly (7), the settlement assembly (7) includes settlement cylinder (71), baffle (72) and flow guide plate (73), the settlement cylinder (71) is connected at the bottom of fixed ring (11), the baffle (72) is connected on the inner bottom wall of settlement cylinder (71), the baffle (72) divides the settlement cylinder (71) into settlement chamber (711) and drainage chamber (712), the bottom of drainage chamber (712) is opened with drainage channel (713), the flow guide plate (73) is connected in the settlement cylinder (71), the flow guide plate (73) is obliquely arranged, and the lowest point of the flow guide plate (73) is located above the settlement chamber (711).

2. The municipal road rapid drainage structure according to claim 1, characterized in that: The trash rack (14) and the fixed cover plate (12) are left with trash blocking gap, a plurality of pollution limiting columns (131) are connected on the trash rack (14), and the pollution limiting columns (131) are located in the trash blocking gap.

3. The municipal road rapid drainage structure according to claim 1, characterized in that: The limiting piece (5) is a sliding block, the fixed cover plate (12) is opened with a limiting arc groove (122), and the center of the limiting arc groove (122) is on the axis of the fixed ring (11), and the limiting piece (5) is slidably fitted in the limiting arc groove (122).

4. The municipal road rapid drainage structure according to claim 1, characterized by: The rotating cover plate (13) and the circular arc edge of the trash frame (14) are connected with rotating arc strips (3), the bottom end of the fixed ring (11) is provided with a sliding ring groove (111), the bottom end of the fixed ring (11) is also connected with a sealing ring (112), the rotating arc strips (3) are slidingly fitted in the sliding ring groove (111) and located between the fixed ring (11) and the sealing ring (112).

5. The municipal road rapid drainage structure according to claim 1, characterized in that: The fixed ring (11) is provided with a mounting assembly (8), the mounting assembly (8) comprises a mounting ring (81), a rotating ring (82) and a limiting block (83), the rotating ring (82) is rotatably connected to the top end of the mounting ring (81), the limiting block (83) is connected to the inner wall of the mounting ring (81), the fixed ring (11) is screwedly fitted in the rotating ring (82) and is insertedly connected with the mounting ring (81), the surface of the fixed ring (11) is provided with a limiting groove (113), the limiting groove (113) is vertically arranged, and the limiting block (83) is slidingly fitted in the limiting groove (113).

6. The municipal road rapid drainage structure according to claim 1, characterized by: The rotating cover plate (13) is provided with a water pressure sensor (41) and a controller (42), the detection end of the water pressure sensor (41) penetrates through the rotating cover plate (13), and the driving member (4) is a driving motor; and the driving member (4) and the water pressure sensor (41) are electrically connected to the controller (42).

7. The municipal road rapid drainage structure according to claim 1, characterized by: The surfaces of the fixed cover plate (12) and the rotating cover plate (13) are connected with a plurality of anti-skid convex patterns (6).

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