A deep and large vertical shaft excavation method using a gripper-type vertical tunnel boring machine

Abstract

The present invention belongs to the technical field of tunnel construction, and specifically is a deep and large vertical shaft excavation method of a support shoe type vertical tunnel boring machine, comprising the following steps: S1: firstly, a staff member performs advanced geological forecast and makes excavation preparation; S2: the tunnel boring machine performs stable shoe support, starts the cutter head, and starts excavation at a predetermined position; S3: after completing a stroke of excavation, the machine is stopped, anchor rods are drilled, a steel mesh is erected, and the next cycle is entered; the excavation preparation in S1 includes stable support of the support shoe, and at the same time, a slag receiving device is in place to transport crushed stone; in S2, the excavation performs real-time posture adjustment according to the geological forecast and controls the parameters of the tunnel boring machine; dust in the excavation is suppressed by using scattered water mist, so as to reduce the influence of dust on the driver, resulting in deviation of the excavation position and affecting the construction progress.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, in particular to a deep and large vertical shaft excavation method of a support shoe type vertical tunnel boring machine. Background Art

[0002] A roadheader is a machine used to dig tunnels in modern society and plays a very important role in the construction of highways and railways.

[0003] A Chinese patent with publication number CN106223971A discloses a tunnel boring machine and a tunnel boring method, including an inner shield connected to the rear end of the cutter disc, and an outer shield mounted on the outside of the inner shield and fixedly connected to the inner shield, a fitting gap is set between the inner shield and the outer shield; an adjusting cylinder is fixed on the inner shield, and the telescopic piston of the adjusting cylinder extends through the fitting gap between the inner shield and the outer shield to support the inner side of the outer shield; a propulsion system is fixedly connected to the inner cavity of the inner shield and is used for propelling the tunnel boring machine.

[0004] In the prior art, when a roadheader is excavating, a large amount of smoke and dust will be generated during the transportation stage of crushed stone, which will affect the driver's vision and easily cause the cutting head to be damaged due to the excessive forward speed of the roadheader, thus affecting the progress of the project.

[0005] To this end, the present invention provides a deep and large vertical shaft excavation method using a gripper-type vertical tunneling machine. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a deep and large vertical shaft excavation method of a gripper-type vertical tunnel boring machine described in the present invention, a deep and large vertical shaft excavation method of a gripper-type vertical tunnel boring machine comprises the following steps:

[0008] S1: First, the staff will conduct advanced geological forecast and make preparations for excavation;

[0009] S2: The tunnel boring machine uses a stabilizing shoe to support the machine, starts the cutterhead, and begins tunneling at the predetermined position;

[0010] S3: After completing one excavation stroke, the machine stops, anchor rods are drilled, steel mesh is erected, and the next cycle begins.

[0011] Preferably, the excavation preparation in S1 includes stable support by the support shoes, and the slag receiving device is in place to transport the gravel; the excavation in S2 performs real-time posture adjustment according to the geological forecast and controls the parameters of the tunnel boring machine; during operation, the gravel in the excavation can be quickly transported through the cooperation of the slag receiving device and the cutter head to reduce internal accumulation, and at the same time, the land conditions are judged according to the geological forecast and the tunnel boring machine is controlled accordingly.

[0012] Preferably, the slag receiving device includes a slag receiving bucket; the middle part of the slag receiving bucket is rotatably connected to a conveyor belt; the top of the slag receiving bucket is rotatably connected to a pair of conveying wheels; a nozzle is fixedly connected to the top of the conveying wheel; a protective cover is fixedly connected to the outside of the nozzle; the top of the protective cover is rotatably connected to a rotating plate; when working, the scattered water mist is used to suppress the dust in the excavation, so as to reduce the impact of the dust on the driver, resulting in deviation of the excavation position and affecting the construction progress.

[0013] Preferably, the side wall of the protective cover is hinged with multiple groups of extrusion plates; multiple groups of No. 1 water leakage holes and No. 2 water leakage holes are provided on the extrusion plate and the protective cover; multiple groups of rubber plates are fixedly connected to the side wall of the extrusion plate close to the No. 2 water leakage hole; during operation, the movement of the rubber plates can be utilized to clean up the gravel blocked by splashing during excavation in the No. 2 water leakage hole, thereby reducing the obstruction of water flow caused by the blockage of the No. 2 water leakage hole and affecting the dust removal effect.

[0014] Preferably, multiple groups of side walls of the No. 2 leakage holes are each provided with a No. 1 magnet; multiple groups of separation plates are hingedly connected to the side walls of the rubber plates; a No. 2 magnet is fixedly connected inside the separation plates; the No. 1 magnet and the No. 2 magnet are magnetically attracted to each other; during operation, the magnetic attraction between the No. 1 magnet and the No. 2 magnet can be used to further clean the dust and impurities in the No. 2 leakage holes, thereby reducing the residual dust and impurities that affect the discharge of water flow and the suppression of dust during excavation.

[0015] Preferably, the side wall of the rubber plate is provided with a No. 1 slide groove; a pair of elastic ropes are fixedly connected to the inner side wall of the No. 1 slide groove; the other ends of the pair of elastic ropes are respectively fixedly connected to the side walls of the separation plate; the side wall of the No. 1 slide groove is hinged with multiple groups of symmetrically arranged limit plates; the side walls on both sides of the limit plates are provided with a pair of support rods; the support rods are hinged to the side wall of the No. 1 slide groove; multiple groups of impact blocks are fixedly connected to the elastic ropes; when working, the impact generated by the collision between the impact blocks and the limit plates can be used to transmit vibration, and when the separation plate scrapes the side wall of the No. 1 magnet, the vibration effect loosens the dust and impurities, further increasing the cleaning effect.

[0016] Preferably, a No. 2 slide groove is provided on the side wall of the No. 1 magnet close to the protective cover; the No. 1 magnet is slidably connected to the side wall of the protective cover; the No. 1 magnet and the protective cover are connected by a No. 1 spring; when working, the elasticity of the No. 1 spring can make the No. 1 magnet displace to a certain extent, thereby increasing adaptability; when blocked, the separation plate can be used to squeeze the No. 1 magnet to facilitate pushing of the blockage and reduce blockage.

[0017] Preferably, the side wall of the No. 1 magnet is fixed with multiple groups of limit blocks; the side wall of the protective cover is provided with a No. 3 slide groove; the interior of the No. 3 slide groove is slidably connected with an impact plate; the No. 3 slide groove and the impact plate are connected by a No. 2 spring; when working, the collision generated by the impact plate and the No. 2 spring can make the vibration further reduce the adhesion of dust on the No. 1 magnet, reduce blockage, facilitate the smooth passage of water, suppress external dust, and provide a good field of vision for the driver.

[0018] Preferably, the protective cover is provided with a plurality of groups of No. 3 water leakage holes on the side wall between a pair of extrusion plates; a pair of drainage fans are provided on the side wall of the No. 3 water leakage hole; when working, the rotation of the drainage fans caused by the impact of the water flow can increase the dispersion effect of the water flow discharged from the No. 3 water leakage hole, further suppress the external dust, and reduce the diffusion of dust.

[0019] Preferably, a pair of corresponding side walls of the No. 1 magnet are fixedly connected with rubber pads; the side walls of the rubber pads are provided with wavy patterns; during operation, the protection of the No. 1 magnet by the rubber pads can reduce the damage of the No. 1 magnet caused by impact, and the provision of the wavy patterns can reduce the retention of large pieces of gravel on the rubber pads.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The deep and large vertical shaft excavation method of a gripper-type vertical tunnel boring machine described in the present invention suppresses dust during excavation by utilizing scattered water mist, thereby reducing the impact of dust on drivers, causing deviations in the excavation position, and affecting the construction progress.

[0022] 2. The deep and large vertical shaft excavation method of a support shoe type vertical tunnel boring machine described in the present invention can clean up the gravel blocked by the splashing in the No. 2 leakage hole by utilizing the movement of the rubber plate, thereby reducing the obstruction of water flow caused by the blockage of the No. 2 leakage hole and affecting the dust removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] Figure 1 is a flow chart of the excavation method of the present invention;

[0025] Figure 2is a stereogram of the present invention;

[0026] Figure 3 is a cross-sectional view of the present invention;

[0027] Figure 4 It is a schematic structural diagram of an extruded plate of the present invention;

[0028] Figure 5 yes Figure 4 A magnified image of point A;

[0029] Figure 6 It is a structural schematic diagram of the rubber sheet of the present invention;

[0030] Figure 7 It is a structural schematic diagram of a No. 1 magnet of the present invention;

[0031] Figure 8 is a structural diagram of Embodiment 2;

[0032] In the figure: 1. slag receiving bucket; 11. conveyor belt; 12. conveyor wheel; 13. nozzle; 14. protective cover; 15. rotating plate; 2. extrusion plate; 21. leakage hole No. 1; 22. leakage hole No. 2; 23. rubber plate; 3. magnet No. 1; 31. separation plate; 32. magnet No. 2; 4. chute No. 1; 41. elastic rope; 42. limit plate; 43. support rod; 44. impact block; 5. chute No. 2; 51. spring No. 1; 6. limit block; 61. chute No. 3; 62. impact plate; 63. spring No. 2; 7. leakage hole No. 3; 71. drainage fan; 8. rubber pad; 81. wave pattern. DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0034] Embodiment 1

[0035] like Figure 1 As shown, a deep and large vertical shaft excavation method of a gripper-type vertical tunnel boring machine according to an embodiment of the present invention comprises the following steps:

[0036] S1: First, the staff will conduct advanced geological forecast and make preparations for excavation;

[0037] S2: The tunnel boring machine uses a stabilizing shoe to support the machine, starts the cutterhead, and begins tunneling at the predetermined position;

[0038] S3: After completing one excavation stroke, the machine stops, anchor rods are drilled, steel mesh is erected, and the next cycle begins.

[0039] like Figure 1As shown, the excavation preparation in S1 includes the stable support of the support shoe, and the slag receiving device is in place to transport the crushed stone; the excavation in S2 is carried out according to the geological forecast. The real-time posture adjustment is controlled to control the parameters of the tunnel boring machine; when working, the crushed stone in the excavation can be quickly transported through the cooperation of the slag receiving device and the cutter head to reduce the accumulation inside. At the same time, the land condition is judged according to the geological forecast, and the tunnel boring machine is controlled accordingly.

[0040] like Figures 2 to 3 As shown, the slag receiving device includes a slag receiving bucket 1; the middle part of the slag receiving bucket 1 is rotatably connected to a conveyor belt 11; the top of the slag receiving bucket 1 is rotatably connected to a pair of conveying wheels 12; the top of the conveying wheel 12 is fixedly connected to a nozzle 13; the outside of the nozzle 13 is fixedly connected to a protective cover 14; the top of the inner top of the protective cover 14 is rotatably connected to a rotating plate 15; when working, after the slag receiving bucket 1 is in place, the crushed stone can be transported by the rotation of a pair of conveying wheels 12 to cooperate with the movement of the conveyor belt 11, and at the same time, the nozzle 13 on the conveying wheel 12 sprays water, and the protective cover 14 can protect the nozzle 13. The impact force of the water drives the rotating plate 15 to rotate, so that the water flow is scattered to suppress the dust in the crushed stone, and the scattered water mist is used to suppress the dust in the excavation, so as to reduce the impact of dust on the driver, resulting in deviation of the excavation position and affecting the construction progress.

[0041] like Figures 3 to 5 As shown, the side wall of the protective cover 14 is hinged with multiple groups of extrusion plates 2; the extrusion plate 2 and the protective cover 14 are provided with multiple groups of No. 1 leakage holes 21 and No. 2 leakage holes 22; the side wall of the extrusion plate 2 close to the No. 2 leakage hole 22 is fixedly connected with multiple groups of rubber plates 23; when working, the rotating plate 15 scatters the water flow to all directions, so that the water flow impacts the extrusion plate 2, and the No. 1 leakage holes 21 and No. 2 leakage holes 22 provided at the same time allow the water flow to pass through and suppress the dust outside. During the movement of the extrusion plate 2, the rubber plate 23 can move toward the No. 2 leakage hole 22. By utilizing the movement of the rubber plate 23, the gravel blocked by the splashing in the No. 2 leakage hole 22 due to excavation can be cleaned, thereby reducing the obstruction of water flow due to the blockage of the No. 2 leakage hole 22, which affects the dust removal effect.

[0042] like Figure 5 to Figure 6As shown, multiple groups of side walls of the No. 2 water leakage holes 22 are each provided with a No. 1 magnet 3; multiple groups of separation plates 31 are hingedly connected to the side walls of the rubber plate 23; a No. 2 magnet 32 ​​is fixedly connected inside the separation plate 31; the No. 1 magnet 3 and the No. 2 magnet 32 ​​are magnetically attracted to each other; during operation, during the movement of the rubber plate 23, the No. 2 magnet 32 ​​is attracted to the No. 1 magnet 3 by the magnetic force, driving the separation plate 31 to expand outward, and the dust and impurities on the side walls of the No. 1 magnet 3 are scraped off. By utilizing the magnetic attraction between the No. 1 magnet 3 and the No. 2 magnet 32, the dust and impurities in the No. 2 water leakage hole 22 can be further cleaned, reducing the residual dust and impurities, which will affect the discharge of water flow and the suppression of dust during excavation.

[0043] like Figure 6 As shown, the side wall of the rubber plate 23 is provided with a No. 1 slide groove 4; the inner side wall of the No. 1 slide groove 4 is fixedly connected with a pair of elastic ropes 41; the other ends of the pair of elastic ropes 41 are respectively fixedly connected to the side walls of the separation plate 31; the side wall of the No. 1 slide groove 4 is hinged with a plurality of groups of symmetrically arranged limit plates 42; the side walls of the limit plates 42 are provided with a pair of support rods 43; the support rods 43 are hinged on the side wall of the No. 1 slide groove 4; and the elastic rope 41 is fixedly connected with a plurality of groups of impact blocks 44; when working, the elastic rope 41 will be pulled to deform during the process of the separation plate 31 expanding outward, driving the impact block 44 and the limit plate 42 to collide and generate vibration. At the same time, a pair of support rods 43 support the limit plate 42 to assist in resetting. The impact generated by the collision between the impact block 44 and the limit plate 42 can be used to transmit the vibration. When the separation plate 31 scrapes the side wall of the No. 1 magnet 3, the vibration effect loosens the dust and impurities, further increasing the cleaning effect.

[0044] like Figure 7 As shown, the side wall of the No. 1 magnet 3 close to the protective cover 14 is provided with a No. 2 slide groove 5; the No. 1 magnet 3 is slidably connected to the side wall of the protective cover 14; the No. 1 magnet 3 and the protective cover 14 are connected by a No. 1 spring 51; when working, after the separation plate 31 is unfolded, the No. 1 magnet 3 can be squeezed, and the No. 1 magnet 3 can be moved by the elasticity of the No. 1 spring 51. The elasticity of the No. 1 spring 51 can be used to make the No. 1 magnet 3 displaced to a certain extent, thereby increasing adaptability. When blocked, the separation plate 31 is used to squeeze the No. 1 magnet 3, which is convenient for pushing the blockage and reducing the blockage.

[0045] like Figure 7As shown, the side wall of the No. 1 magnet 3 is fixedly connected with multiple groups of limit blocks 6; the side wall of the protective cover 14 is provided with a No. 3 slide groove 61; the inside of the No. 3 slide groove 61 is slidably connected with a strike plate 62; the No. 3 slide groove 61 and the strike plate 62 are connected by a No. 2 spring 63; during operation, when the No. 1 magnet 3 is squeezed and moves toward the side wall of the protective cover 14, the strike plate 62 contacts the strike plate 62 under the elastic action of the No. 2 spring 63, resulting in collision and extrusion, and then the strike plate 62 is reset by the No. 2 spring 63, and the collision operation is repeated. The collision generated by the strike plate 62 and the No. 2 spring 63 can make the vibration further reduce the adhesion of dust on the No. 1 magnet 3, reduce blockage, facilitate the smooth passage of water, suppress external dust, and provide a good field of vision for the driver.

[0046] like Figure 4 As shown, the protective cover 14 is provided with a plurality of groups of No. 3 water leakage holes 7 on the side wall between a pair of extrusion plates 2; a pair of drainage fans 71 are provided on the side wall of the No. 3 water leakage hole 7; during operation, when the water flow impacts the rotating plate 15 to rotate it, part of the water flow is sprayed toward the center position of the protective cover 14 due to the curvature of the extrusion plate 2, and the rotation of the drainage fan 71 can make the water flow dispersed for a second time and discharged outward through the No. 3 water leakage hole 7, and the rotation of the drainage fan 71 caused by the impact of the water flow can increase the dispersion effect of the water flow discharged from the No. 3 water leakage hole 7, further suppress the external dust, and reduce the diffusion of dust.

[0047] Embodiment 2

[0048] like Figure 8 As shown, compared with Example 1, another implementation of the present invention is: a pair of corresponding side walls of the No. 1 magnet 3 are fixedly connected with rubber pads 8; the side walls of the rubber pads 8 are provided with wave patterns 81; during operation, when the No. 1 magnet 3 is impacted by gravel, the No. 1 magnet 3 can be protected by the elasticity of the rubber pads 8 themselves, and the protection of the No. 1 magnet 3 by the rubber pads 8 can reduce the damage of the No. 1 magnet 3 caused by the impact, and at the same time, the opening of the wave patterns 81 can reduce the retention of large pieces of gravel on the rubber pads 8.

[0049] During operation, through the cooperation of the slag receiving device and the cutter disc, the crushed stones in the excavation can be transported quickly to reduce the accumulation inside. At the same time, the land conditions are judged according to the geological forecast, and the excavator is controlled accordingly. After the slag receiving bucket 1 is in place, the crushed stones can be transported by the rotation of a pair of conveying wheels 12 to cooperate with the movement of the conveyor belt 11. At the same time, the nozzle 13 on the conveying wheel 12 sprays water, and the protective cover 14 can protect the nozzle 13. The impact force of the water drives the rotating plate 15 to rotate, so that the water flow is scattered and the dust in the crushed stones is suppressed. The rotating plate 15 scatters the water flow to all sides, so that the water flow impacts the extrusion plate 2. At the same time, the No. 1 leakage hole 21 and the No. 2 leakage hole 22 opened can allow the water flow to pass through and suppress the dust outside. During the movement of the extrusion plate 2, the rubber plate 23 can move toward the No. 2 leakage hole 22. During the movement of the rubber plate 23, the No. 2 magnet 32 ​​is affected by the No. 1 magnet 3, the magnetic attraction effect drives the separation plate 31 to expand outward, and the dust and impurities on the side wall of the No. 1 magnet 3 are scraped off. In the process of the separation plate 31 expanding outward, the elastic rope 41 is pulled to deform it, driving the impact block 44 and the limit plate 42 to collide and generate vibration. At the same time, a pair of support rods 43 support the limit plate 42 to assist in resetting. After the separation plate 31 is expanded, the No. 1 magnet 3 can be squeezed, and the No. 1 magnet 3 can be moved by the elasticity of the No. 1 spring 51. When the No. 1 magnet 3 is squeezed and moves toward the side wall of the protective cover 14, the impact plate 62 contacts the impact plate 62 under the elastic action of the No. 2 spring 63, resulting in collision and extrusion. The impact plate 62 is reset by the No. 2 spring 63, and the collision operation is repeated. When the water flow impacts the rotating plate 15 to rotate it, part of the water flow is sprayed toward the center of the protective cover 14 due to the curvature of the squeezing plate 2. The rotation of the drainage fan 71 can make the water flow secondary dispersed and discharged outward through the No. 3 leakage hole 7.

[0050] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0052] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A deep and large vertical shaft excavation method using a gripper-type vertical tunnel boring machine, characterized in that: A deep and large vertical shaft excavation method using a gripper-type vertical tunnel boring machine comprises the following steps: S1: First, the staff will conduct advanced geological forecast and make preparations for excavation; S2: The tunnel boring machine uses a stabilizing shoe to support the machine, starts the cutterhead, and begins tunneling at the predetermined position; S3: After completing one excavation stroke, the machine stops, anchors are drilled, steel mesh is erected, and the next cycle begins; The excavation preparation in S1 includes stable support of the support shoe, and the slag receiving device is in place to transport the crushed stone; the excavation in S2 is carried out according to the geological forecast in real time to control the parameters of the tunnel boring machine; The slag receiving device comprises a slag receiving bucket (1); a conveyor belt (11) is rotatably connected to the middle of the slag receiving bucket (1); a pair of conveying wheels (12) are rotatably connected to the top of the slag receiving bucket (1); a nozzle (13) is fixedly connected to the top of the conveying wheel (12); a protective cover (14) is fixedly connected to the outside of the nozzle (13); a rotating plate (15) is rotatably connected to the top of the interior of the protective cover (14); The side wall of the protective cover (14) is hinged with a plurality of extrusion plates (2); the extrusion plates (2) and the protective cover (14) are both provided with a plurality of first water leakage holes (21) and second water leakage holes (22); the side wall of the extrusion plate (2) close to the second water leakage hole (22) is fixedly connected with a plurality of rubber plates (23); The side walls of the plurality of groups of the second water leakage holes (22) are all provided with a first magnet (3); the side walls of the rubber plate (23) are hinged with a plurality of separation plates (31); the separation plates (31) are fixedly provided with a second magnet (32); the first magnet (3) and the second magnet (32) are magnetically attracted to each other; The side wall of the rubber plate (23) is provided with a first slide groove (4); a pair of elastic ropes (41) are fixedly connected to the inner side wall of the first slide groove (4); the other ends of the pair of elastic ropes (41) are respectively fixedly connected to the side wall of the separation plate (31); the side wall of the first slide groove (4) is hinged with a plurality of symmetrically arranged limit plates (42); a pair of support rods (43) are provided on the side walls of the limit plates (42); the support rods (43) are hingedly connected to the side wall of the first slide groove (4); a plurality of impact blocks (44) are fixedly connected to the elastic rope (41); A second slide groove (5) is provided on the side wall of the first magnet (3) close to the protective cover (14); the first magnet (3) is slidably connected to the side wall of the protective cover (14); and the first magnet (3) and the protective cover (14) are connected via a first spring (51).

2. A deep and large vertical shaft excavation method using a gripper-type vertical tunnel boring machine according to claim 1, characterized in that: The side wall of the No. 1 magnet (3) is fixedly connected with a plurality of groups of limit blocks (6); the side wall of the protective cover (14) is provided with a No. 3 slide groove (61); the interior of the No. 3 slide groove (61) is slidably connected with an impact plate (62); the No. 3 slide groove (61) and the impact plate (62) are connected via a No. 2 spring (63).

3. A deep and large vertical shaft excavation method using a gripper-type vertical tunnel boring machine according to claim 2, characterized in that: The protective cover (14) is provided with a plurality of groups of No. 3 water leakage holes (7) on the side wall between a pair of extrusion plates (2); and a pair of drainage fans (71) are provided on the side wall of the No. 3 water leakage holes (7).

4. A deep and large vertical shaft excavation method using a gripper-type vertical boring machine according to claim 3, characterized in that: The corresponding side walls of a pair of the first magnets (3) are both fixedly connected with rubber pads (8); the side walls of the rubber pads (8) are provided with wavy patterns (81).

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