JP2009046877A - Lid for underground structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lid for an underground structure, which blocks an opening communicating with the underground structure and formed in the ground, at a height that is flush with the ground surface, wherein the lid is effectively prevented from degradation of the anti-skid performance of protrusion bodies thereof even if abrasion of the protrusion bodies develops. <P>SOLUTION: The lid for the underground structure is formed of: the protrusion bodies 10 protruding upward; and overhanging bodies 16, 17 overhanging sideways from respective side surfaces 11, 13 of each protrusion body 10, and having polygonal upper surfaces 161, 171 at a height lower than a protruding end face 12 of each protrusion body 10. When the protruding end face 12 of the protrusion body 10 is worn out to such an extent as to have the same height as that of the upper surfaces 161, 171 of the respective overhanging bodies 16, 17, the number of corners of a contact surface T<SB>1</SB>consisting of the protruding end face 12 and the upper surfaces 161, 171, is larger than the number of corners 121 of the protruding end face 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lid for an underground structure that closes an opening provided in the ground, which is connected to the underground structure, at the same height as the ground.

  When a vehicle or a pedestrian passes over the above-mentioned underground structure lid provided on a roadway or a sidewalk, the vehicle or the pedestrian is particularly slippery when the underground structure lid is wet. For this reason, conventionally, proposals have been made to disperse and project protrusions protruding upward in the underground structure lid and prevent the vehicle or pedestrian from slipping by these protrusions (for example, Patent Document 1).

  In the underground structure lid described in Patent Document 1, attempts have been made not to lower the slip resistance performance that prevents the vehicle or pedestrian from slipping even if the protruding tip surface of the protruding body is worn.

By the way, as a result of repeated researches by the inventors of the present invention, the slip resistance performance of the lid for an underground structure is not limited to the position of the projecting body. We found that it depends on the number of corners on the top surface. That is, in order to improve the slip resistance performance of the lid for underground structures, the contact area with the tire or the like is reduced, the amount of biting of the tire or the like is increased, and the number of corner portions on which the tire or the like is caught preferentially. It was concluded that it is important to increase
Japanese Patent No. 3094008

  Based on this conclusion, the underground structure lid proposed by the above-mentioned Patent Document 1 is verified. In the underground structure cover proposed by the above-mentioned Patent Document 1, when the wear of the projecting body proceeds, the projecting body The number of corners on the upper surface does not change, only the area of the upper surface increases, and a significant decrease in slip resistance performance cannot be avoided.

  In view of the above circumstances, an object of the present invention is to provide a lid for an underground structure that effectively suppresses a decrease in slip resistance performance even when the wear of a protrusion progresses.

The lid for an underground structure of the present invention that solves the above-mentioned object is a lid for an underground structure that closes an opening provided in the ground, which is connected to the underground structure, at the same height as the ground.
A projecting body projecting upward;
Projecting laterally from the side surface of the projecting body, and a projecting body having a polygonal upper surface below the projecting tip surface of the projecting body,
When the protruding tip surface of the protruding body is worn and the protruding tip surface and the upper surface of the overhanging body are at the same height, the number of corners of the contact surface consisting of the protruding tip surface and the upper surface is The number of corners of the protruding tip surface is larger than the number of corners.

  According to the cover for an underground structure of the present invention, the protruding tip surface of the protruding body is worn and the protruding tip surface when the protruding tip surface and the upper surface of the overhanging body are at the same height position, and the Although the area of the contact surface composed of the upper surface increases, the number of corners of the contact surface also increases. For this reason, the slip resistance performance reduced by the increase in the area of the contact surface of the projecting body is compensated for by the increase in the number of corners of the contact surface. As a result, the slip resistance performance is reduced. Effectively suppressed.

  Moreover, in the lid for an underground structure according to the present invention, the overhanging body is such that the edge on the front end side in the overhanging direction on the upper surface is shorter than the edge of the projecting body where the side surface and the protruding front end surface intersect. The aspect which is is preferable.

  According to this aspect, the area of the upper surface of the projecting body is reduced, and an increase in the area of the contact surface is suppressed. For this reason, a decrease in slip resistance is also effectively suppressed.

Here, this underground structure lid is circular,
The protrusion may be disposed along the circumferential direction of the underground structure lid, or the protrusion is disposed along the radial direction of the underground structure lid. It may be.

  As described above, the anti-slip performance is also improved by devising the arrangement position of the protrusions.

  According to the lid for an underground structure of the present invention, it is possible to effectively suppress the slip resistance performance from being deteriorated even when the wear of the protrusion progresses.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a plan view of an iron cover for a manhole, which is an embodiment of the cover for an underground structure according to the present invention.

  The iron lid 1 shown in FIG. 1 closes a circular opening provided in the ground, which is connected to an underground structure such as a sewer buried in the ground, at the same height as the ground. A receiving frame (not shown) is provided. An iron lid 1 shown in FIG. 1 is fitted into the receiving frame to close the opening. The iron lid 1 is a circular one having a diameter of 600 mm.

As shown in FIG. 1, a plurality of projecting bodies 10 are distributed on the surface 1 a of the iron lid 1. These protrusions 10 are I-shaped ones protruding upward (front side of the paper). In the iron lid 1 shown in FIG. 1, the protrusion 10c disposed along the circumferential direction of the iron cover 1 and the protrusion 10r disposed along the radial direction of the iron cover 1 are combined to form an iron cover. The pattern of the surface 1a is comprised. That is, the iron lid surface 1a is provided with a protrusion 10c whose longitudinal direction faces the circumferential direction and a protrusion 10r whose longitudinal direction faces the radial direction. Projecting member 10r, which are arranged along the radial direction are aligned in the circumferential direction, the inner circumferential side of the Tetsufuta 1, the sequence r ₁ of the projecting member 10c arranged along the circumferential direction, along the radial direction and line r ₂ of arranged projecting member 10r Te are provided alternately toward the outer peripheral side from Tetsufuta center. Also, the outermost periphery, the arrangement r ₃ of the projecting member 10r, which are arranged along the radial direction is provided, the arrangement r ₄ inside the arrangement of outermost r _3, in the radial direction arranged The projecting bodies 10r and the projecting bodies 10c arranged along the circumferential direction are alternately provided in the circumferential direction. In the iron lid 1 shown in FIG. 1, the slip resistance performance for preventing the vehicle or pedestrian from slipping is enhanced by the arrangement of the plurality of protrusions 10.

  FIG. 2 is a perspective view of the protrusion shown in FIG. 3 is a plan view of the projecting body, and FIG. 4 is a front view of the projecting body.

  The protrusion length of the protrusion 10 shown in FIG. 2 is 6 mm. That is, as shown in FIG. 4, the height position of the protruding tip surface 12 of the protruding body 10 is 6 mm higher than the height position of the bottom surface B of the protruding body 10. Further, as clearly shown in FIG. 2, three cutout portions 111, 112, and 113 connected to the protruding tip surface 12 are provided on one side surface 11 extending in the longitudinal direction W of the I-shaped protruding body 10. It is provided in the longitudinal direction W with an interval. By providing these three notches 111, 112, and 113, the area of the protruding tip surface 12 is suppressed small. As shown in FIG. 3, the length in the longitudinal direction W of the protruding tip surface 12 (the length of the edge 14 of the protruding body 10 where the side surface 11 in the longitudinal direction W and the protruding tip surface 12 intersect) L1 is 30 mm. The length L2 in the short direction S perpendicular to the longitudinal direction W (the length of the edge 15 of the projecting body 10 where the side surface 13 in the short direction S and the projecting tip surface 12 intersect) L2 is 5 mm.

  A first large projecting body 16 projecting in the lateral direction (short direction S) is provided in each of the notches 111 and 113 at both ends of the side surface 11 in the longitudinal direction. Further, a second large projecting body 17 projecting in the longitudinal direction S is provided on the side surface 13 in the short direction S. The first overhanging body 16 and the second overhanging body 17 correspond to an example of the overhanging body referred to in the present invention. The I-shaped projecting body 10 is provided with four first overhanging bodies 16 and two second overhanging bodies 17. As shown in FIG. 4, the upper surfaces 161 and 171 of the first large projecting body 16 and the second large projecting body 17 are at a position 2 mm lower than the height position of the protruding tip surface 12. As shown in FIG. 3, the length L3 of the leading end edge 1611 in the protruding direction on the upper surface 16 of the first large projecting body 16 is shorter than the length L1 of the edge 14 and the projecting surface on the upper surface 171 of the second large projecting body. The length L4 of the direction leading edge 1711 is shorter than the length L2 of the edge 15.

  Also, as shown in FIGS. 2 and 3, these upper surfaces 161 and 171 are polygonal surfaces that taper from the projecting body side surfaces 11 and 13 toward the protruding end edges 1611 and 1711. Furthermore, these upper surfaces 161 and 171 are surfaces that expand in the horizontal direction. If the second large projecting member upper surface 171 is described as an example, as shown in the left circle at the bottom of FIG. By making the upper surface into a surface 171 ′ that gradually inclines upward from the projecting body side surface 13 toward the protruding end edge 1711, the edge angle at the protruding end edge 1711 becomes 90 °, and the slip resistance performance is further improved. improves. On the other hand, as shown in the right circle at the bottom of FIG. 4, the upper surface of the upper surface is changed to a surface 171 ″ that gradually slopes downward from the side surface 13 of the projecting body toward the distal end edge 1711 in the protruding direction. The drainage property on the surface 1a is improved. The same applies to the upper surface 16 of the first overhanging body.

  Similarly, as shown in FIG. 4, the inclination angle θ <b> 1 of the first overhanging body 16 in the longitudinal direction W on the side surfaces 162 and 163 at both ends in the longitudinal direction W is set in the lateral direction S of the projecting body 10. The inclination angle θ2 of the side surface 13 in the longitudinal direction W is larger. By doing so, the edge angle at the edge 164 extending in the protruding direction of the first large projecting body upper surface 161 is closer to 90 ° than the edge angle at the edge 15 of the protruding tip surface 12.

  Further, on the side surface 165 in the longitudinal direction of any of the four first large projecting bodies 16, a small projecting body 18 projecting toward the side (short direction S) is provided. As shown in FIG. 4, the upper surface 181 of the small projecting body 18 is at a position 4 mm lower than the height position of the protruding tip surface 12. Further, as shown in FIG. 3, the length L5 of the overhanging direction leading edge 1811 on the small overhanging body upper surface 181 is shorter than the length L3 of the overhanging direction leading edge 1611 on the first large overhanging body upper surface 161. The upper surface 181 is also a polygonal surface that tapers toward the tip in the overhang direction. The upper surface 181 shown in FIG. 4 is also a surface that expands in the horizontal direction. However, the surface may be gradually inclined upward to further improve the slip resistance, or the surface may be gradually inclined downward to improve drainage. May be raised.

  The protrusion 10 described above is gradually worn out by rubbing against the tires of the vehicle passing over the iron lid 1 and the soles of pedestrians.

  FIG. 5A is a diagram showing a state in which the protrusion shown in FIG. 2 provided on a new iron lid starts to wear, and FIG. 5B is a front end surface of the protrusion shown in FIG. It is a figure which shows a protrusion when 2 mm is worn out.

The anti-slip performance of the iron lid can be improved by devising the arrangement position of the protrusion 10 as shown in FIG. 1, but the area of the upper surface (contact surface) of the protrusion that the tire or the like contacts and It depends on the number of corners. The iron lid 1 shown in FIG. 1 is a cast product such as ductile cast iron, and the protruding body 10 is also formed by casting. For this reason, the protrusion 10 is provided with an inclination necessary for demolding at the time of casting. That is, the protrusion 10 is provided with an inclination that tapers toward the front end in the protrusion direction, and the area of the upper surface of the protrusion inevitably increases as wear of the protrusion 10 progresses. Moreover, as shown to Fig.5 (a), as for the protrusion 10, the corner | angular part 121 of the protrusion front end surface 12 wears preferentially. Eventually, when the protruding tip surface is worn by 2 mm, as shown in FIG. 5B, the protruding tip surface 12, the upper surface 161 of the first overhanging body 16 and the second overhanging body 17 at a position lowered by 2 mm. of the upper surface becomes 171 and the same height position, the tire or the like is in contact with the contact surface T ₁ consisting of an upper surface 161, 171 Metropolitan a projecting distal end face 12.

  As a result of intensive research, the present inventors have improved the slip resistance performance of the iron lid by reducing the area of the upper surface of the projecting body in contact with the tire and the like, and increasing the amount of biting into the tire and the like, It was concluded that it is important to increase the number of corners on which tires etc. are preferentially caught. Therefore, the present inventor has focused on the number of corners in an iron lid, which is a cast product, because an increase in the area of the protrusion contact surface due to the progress of wear is inevitable.

  6A is a plan view of the projecting tip surface of the projecting body shown in FIG. 2 provided on a new iron lid, and FIG. 6B is a plan view of the contact surface shown in FIG. 5B. It is.

As shown in FIG. 6A, the protruding tip surface 12 of the protruding body provided on the new iron lid has a polygonal shape, and the number of corners on the protruding tip surface 12 is 28 in total. In contrast, as shown in FIG. 6 (b), the number of corners of the contact surface T ₁ of the result of the wear has progressed is 36 in total. Therefore, when the wear progresses and the projecting tip surface 12 of the projecting body, the upper surface 161 of the first large projecting body, and the upper surface 171 of the second large projecting body are at the same height, the number of corners is eight. The number also increases. This means that the number of corners has increased by more than 20%, and the slip resistance performance that has decreased due to the increase in the area of the contact surface of the projecting body is compensated by the increase in the number of corners of the contact surface. As a result, a decrease in slip resistance is effectively suppressed. Thus, it is preferable that the increase rate of the number of corners is 20% or more. In the iron lid 1 shown in FIG. 1, the projecting tip surface 12 of the projecting body 10, the upper surface 161 of the first large projecting body 16, and the upper surface 171 of the second large projecting body 17 are at the same height position. As for the slip resistance performance between the two, the desired performance is ensured even if the area is increased to some extent by reducing the area of the protruding tip surface 12 of the protruding body 10 in a new state in advance. It is designed so that the protruding tip surface 12, the upper surface 161 of the first large projecting body 16, and the upper surface 171 of the second large projecting body 17 are at the same height at a timing when it is difficult to ensure performance. . In order to reduce the area of the protruding tip surface 12 of the protruding body 10 in a new state, a groove extending in the longitudinal direction W may be provided on the protruding tip surface 12. Moreover, the shape of the protrusion front end surface 12 of the protrusion 10 in a new state is not limited to a polygonal shape, and if the area is sufficiently small, a desired slip resistance performance can be obtained even in a circular shape.

Also, as shown in FIG. 3, the relationship of the length L3 of the extending direction leading edge 1611 <the length L1 of the edge 14 and the length L4 of the protruding edge 1711 <the length L2 of the edge 15 is satisfied. since it is established, any area first Daihari Detai top surface 16 and a second Daihari Detai top 171 is also reduced, increasing the area of the contact surface T ₁ is suppressed. For this reason, a decrease in slip resistance is also effectively suppressed.

  Furthermore, as shown in FIG. 4, the relationship of the inclination angle θ1 of the first overhanging body 16> the inclination angle θ2 of the projecting body 10 is established, so that the edge 164 of the upper surface 161 of the first overhanging body The edge angle becomes larger than the edge angle at the edge 15 of the projecting tip surface 12, and the slip resistance performance that is reduced by increasing the area of the contact surface of the projecting body is compensated by the increased edge angle, and the slip resistance is improved. The decline in performance is more effectively suppressed.

  In the iron lid 1 shown in FIG. 1, when the protruding tip surface 12 of the protruding body 10 is worn beyond 3 mm, it is time to replace it with a new one. Here, the tire of the vehicle passing over the iron lid 1 may contact the protrusion 10 from directly above, or may contact it obliquely. In particular, in the projecting body 10 in the state shown in FIG. 5B, the tire that contacts obliquely is caught by the small projecting body 18 provided with the upper surface 181 at a position lowered by 4 mm, and the slip resistance performance is further improved.

  Note that the upper surface 161 of the first overhanging body 16 shown in FIG. 4 is lowered by 1 mm so that the upper surface 161 comes to a position 3 mm lower than the projecting tip surface 12 of the projecting body 10 provided on the new iron lid. Also good. In this way, when the protruding tip surface 12 is worn by 2 mm, the protruding tip surface 12 and the upper surface 171 of the second overhanging body 17 at a position lowered by 2 mm are at the same height position, and the angle of the contact surface The increase in the number of parts compensates for a decrease in slip resistance, and the upper surface 161 of the first overhanging body 16 lowered by 1 mm functions effectively for tires that contact obliquely. Moreover, the iron cover which lowered | hung the upper surface 171 of the 2nd overhang | projection body 17 shown in FIG. 4 1 mm may be sufficient. That is, in the iron lid in which the upper surface 171 of the second overhanging body 17 comes to a position 3 mm lower than the projecting tip surface 12 of the projecting body 10 provided on the new iron lid, if the projecting tip surface is worn by 2 mm, the projecting tip The surface 12 and the upper surface 161 of the first overhang body 16 at a position lowered by 2 mm are at the same height, and the number of corners of the contact surface does not change at this stage. However, it is possible to ensure the desired slip resistance performance even in the area of the contact surface at this stage, and when the protruding tip surface is further worn by 1 mm (3 mm in total), the contact surface shown in FIG. It becomes a contact surface similar to. As expected, if the area of the contact surface increases so far, it becomes difficult to ensure the desired slip resistance performance, but this increases the number of corners of the contact surface, so that the decrease in slip resistance performance is compensated for, Even at the last time of replacement with the iron lid, the desired slip resistance performance can be secured firmly.

  FIG. 7 is a plan view of an iron lid for a machine hall, which is a second embodiment of the lid for an underground structure according to the present invention.

  Similarly to the iron lid shown in FIG. 1, the iron lid 2 shown in FIG. 7 closes a circular opening provided on the ground at the same height as the ground. The iron lid 2 is a circular cast product having a diameter of 300 mm. As described above, the lid for an underground structure according to the present invention may be a large iron lid having a diameter exceeding 600 mm regardless of the size, or may be square regardless of the shape. Also, it is not limited to the use, but the iron cover for the joint groove that closes the opening connected to the underground structure for power transmission and communication, etc., the cover for the sewage basin, the cover for the fire hydrant, the cover for the water control valve, the cover for the gate valve , A lid for an air valve, a lid for a gas pipe, a lid for a water meter, and the like.

  The same I-shaped protrusions 10 as the protrusions shown in FIG. 2 are dispersedly arranged on the surface 2a of the iron lid 2 shown in FIG. In the iron lid 2, any of the protrusions 10 is arranged along the radial direction. That is, the protrusions 10 whose longitudinal direction is directed in the radial direction are arranged in the circumferential direction on the outermost periphery, and on the inner side, the protrusions 10 whose longitudinal direction is directed in the radial direction are shifted in the circumferential direction while shifting in the radial direction. Are lined up.

  Even in this iron lid 2, the slip resistance performance is enhanced by the arrangement of the plurality of protrusions 10 as described above, and the slip resistance performance reduced by the increase in the area of the contact surface of the protrusions 10 is reduced. The increase in the number of corners of the surface is compensated, and as a result, the reduction in slip resistance is effectively suppressed.

  FIG. 8 is a plan view of an iron cover for a manhole, which is a third embodiment of the cover for an underground structure according to the present invention.

  The iron lid 3 shown in FIG. 8 is a circular cast product having a diameter of 600 mm, which is the same as the iron lid 1 shown in FIG. The same I-shaped protrusions 10 as the protrusions shown in FIG. 2 are dispersedly arranged on the surface 3a of the iron lid 3, and Y-shaped protrusions 20 are also dispersedly arranged. Even in this iron lid 3, the anti-slip performance is enhanced by the arrangement of these two types of protrusions 10 and 20. All of the I-shaped protrusions 10 are arranged along the radial direction.

  FIG. 9 is a view showing the Y-shaped protrusion shown in FIG.

  FIG. 9A shows a perspective view of the Y-shaped protrusion 20 shown in FIG. 8, and FIG. 9B shows a plan view of the protrusion 20. FIG. A front view of the protrusion 20 is shown in (c).

  The Y-shaped projecting body 20 shown in FIG. 9 is a trifurcated branch of the I-shaped projecting body 10 shown in FIG. 2, and the description overlapping with the description of the I-shaped projecting body 10 will be omitted below. Sometimes.

  The protruding length of the Y-shaped protrusion 20 shown in FIG. 9 is also 6 mm, similar to the I-shaped protrusion 10 shown in FIG. 9A, the side surface 21 extending in each of the three directions of the Y-shaped projecting body 20 is provided with a notch 211 connected to the projecting tip surface 22. As shown in FIG. Also in the Y-shaped projecting body 20 shown in FIG. 9, the area of the projecting tip surface 22 is suppressed to be small by the notch 211. Further, as shown in FIG. 9B, the protruding tip surface 22 has a size inscribed in a circle R having a diameter of 27 mm.

  As shown to Fig.9 (a), the 1st overhang | projection body 23 projected toward the side is provided in the side surface 21 extended in each of three directions. Moreover, the 2nd overhang | projection body 25 protruded toward the side which becomes further ahead is also provided in the side surface 24 which becomes a front-end | tip of each of three directions. The Y-shaped projecting body 20 is provided with six first large projecting bodies 23 and three second large projecting bodies 25. As shown in FIG. 9C, the upper surfaces 231 and 251 of each of the first large projecting body 23 and the second large projecting body 25 are in a position 2 mm lower than the height position of the protruding tip surface 22. . As shown in FIG. 9B, these upper surfaces 231 and 251 are polygonal surfaces that taper from the projecting body side surfaces 21 and 24 toward the protruding end edges 2311 and 2511. Further, the length L6 of the protruding end edge 2311 on the upper surface 231 of the first overhanging body 231 is longer than the length L7 of the edge 26 of the protruding body 20 where the side surface 21 extending in each of the three directions and the protruding tip surface 22 intersect. The length L8 of the projecting end tip edge 2511 on the upper surface 251 of the second large projecting body is the length of the edge 27 of the projecting body 20 where the side surface 24 and the projecting tip surface 22 intersect in the three directions. Shorter than L9. Further, each of the six first large projecting bodies 23 has a small projecting body 28 provided with an upper surface 281 at a position 4 mm below the projecting tip surface 22 (see FIG. 9C).

  FIG. 10A is a plan view of the projecting tip surface of the projecting body shown in FIG. 9 provided on a new iron lid, and FIG. 10B is a plan view of the projecting tip surface shown in FIG. It is a top view of the contact surface in the protrusion which was worn out.

As shown in FIG. 10A, the protruding tip surface 22 of the Y-shaped protrusion provided on the new iron lid is also polygonal, and the number of corners on the protruding tip surface 22 is 45 in total. is there. In contrast, as shown in FIG. 10 (b), the protruding end face 22, the corners of the contact surface T ₂ consisting of the upper surface 251. the upper surface 231 and a second Daihari Detai first Daihari Detai Is 57 in total. Therefore, in this Y-shaped projecting body 20, when the projecting tip surface is worn by 2 mm, the number of corners increases by twelve, so that the slip resistance performance is supplemented, and the reduction of the slip resistance performance is effectively suppressed.

  Here, a cross-shaped protrusion may be provided on the iron lid surface 2a instead of the Y-shaped protrusion 20 shown in FIG.

  FIG. 11 is a perspective view showing a cross-shaped protrusion.

  The cross-shaped projecting body 30 shown in FIG. 11 is like the I-shaped projecting body 10 shown in FIG. 2 orthogonal to each other, and the description overlapping with the description of the I-shaped projecting body 10 will be omitted below. Sometimes. The projecting tip surface 32 of the cross-shaped projecting body 30 shown in FIG. 11 has the same area as that of the projecting tip surface 32 as in the case of the Y-shaped projecting body 20 shown in FIG. ) Inscribed in the circle R shown in FIG. A first large projecting body 33 projecting sideways is provided on the side surface 31 extending in each of the four directions, and the side surface 34 serving as the tip in each of the four directions is further projecting toward the front side. A second overhang 35 is provided. The cross-shaped projecting body 30 is provided with eight first large projecting bodies 23 and four second large projecting bodies 25. Similarly to the Y-shaped projecting body 20 shown in FIG. 9, the upper surfaces 331 and 351 of the first large projecting body 33 and the second large projecting body 35 are also lowered by 2 mm from the height position of the projecting tip surface 32. It is a polygonal surface at a position. Further, the lengths of the protruding direction leading edges 3311 and 3511 on the upper surfaces 331 and 351 are kept short. Further, each of the eight first large projecting bodies 23 has a small projecting body 38 provided with an upper surface 381 at a position 4 mm below the projecting tip surface 32.

  12A is a plan view of the protruding tip surface of the protruding body shown in FIG. 11 provided on a new iron lid, and FIG. 12B is a plan view of the protruding tip surface shown in FIG. It is a top view of the contact surface in the protrusion which was worn out.

As shown to Fig.12 (a), the number of the corner | angular parts in the protrusion front end surface 32 of the cross-shaped protrusion provided in the new iron cover is 76 pieces in total. In contrast, as shown in FIG. 12 (b), the protruding end face 32, the corners at the interface T ₃ consisting of the upper surface 351 Metropolitan of top 331 and a second Daihari Detai first Daihari Detai Is a total of 92. Therefore, in this cross-shaped projecting body 30, when the projecting tip surface is worn by 2 mm, the number of corners increases by 16, and this projecting body 30 also compensates for slip resistance.

  As described above, according to the iron lids 1 to 3 in the present embodiment, it is possible to effectively suppress the slip resistance performance from being lowered even when the protrusions 10 to 30 are worn.

It is a top view of the iron cover for manholes which is one Embodiment of the cover for underground structures of this invention. It is a perspective view of the protrusion shown in FIG. It is a top view of the protrusion shown in FIG. It is a front view of the protrusion shown in FIG. FIG. 5A is a diagram showing a state in which the protrusion shown in FIG. 2 provided on a new iron lid starts to wear, and FIG. 5B is a front end surface of the protrusion shown in FIG. It is a figure which shows a protrusion when 2 mm is worn out. 6A is a plan view of the projecting tip surface of the projecting body shown in FIG. 2 provided on a new iron lid, and FIG. 6B is a plan view of the contact surface shown in FIG. 5B. It is. It is a top view of the iron cover for machine holes which is 2nd Embodiment of the cover for underground structures of this invention. It is a top view of the iron cover for manholes which is 3rd Embodiment of the cover for underground structures of this invention. It is a figure which shows the Y-shaped protrusion shown in FIG. FIG. 10A is a plan view of the projecting tip surface of the projecting body shown in FIG. 9 provided on a new iron lid, and FIG. 10B is a plan view of the projecting tip surface shown in FIG. It is a top view of the contact surface in the protrusion which was worn out. It is a perspective view which shows a cross-shaped protrusion. 12A is a plan view of the protruding tip surface of the protruding body shown in FIG. 11 provided on a new iron lid, and FIG. 12B is a plan view of the protruding tip surface shown in FIG. It is a top view of the contact surface in the protrusion which was worn out.

Explanation of symbols

1, 2, 3 Iron lid 10, 20, 30 Protruding body 11, 13, 21, 24, 31, 34 Side surface 12, 22, 32 Protruding tip surface 121 Corner portion 16, 23, 33 First overhanging body 161, 231, 331 Upper surface 17, 25, 35 Second overhang 171, 251, 351 Upper surface 18, 28, 38 Small overhang T ₁ , T ₂ , T ₃ contact surface

Claims (4)

In the lid for the underground structure that closes the opening provided in the ground that leads to the underground structure at the same height as the ground,
A projecting body projecting upward;
Projecting laterally from the side surface of the projecting body, and a projecting body having a polygonal upper surface below the projecting tip surface of the projecting body,
The number of corners of the contact surface composed of the protruding tip surface and the upper surface when the protruding tip surface of the protruding body is worn and the protruding tip surface and the upper surface of the overhanging body are at the same height position. An underground structure lid characterized by being larger than the number of corners of the projecting tip surface.   2. The overhanging body according to claim 1, wherein an edge of the top surface in the overhanging direction on the upper surface is shorter than an edge of the projecting body where the side surface and the protruding front end surface intersect. Cover for underground structures. This underground structure lid is circular,
2. The underground structure lid according to claim 1, wherein the projecting body is disposed along a circumferential direction of the underground structure lid. This underground structure lid is circular,
2. The underground structure lid according to claim 1, wherein the projecting bodies are arranged along a radial direction of the underground structure lid.

Images