JP7205890B2 - Lid receiving frame set for underground structures - Google Patents

Description

TECHNICAL FIELD The present invention relates to an underground structure lid receiving frame set including a metal receiving frame defining an opening leading to an underground structure and a metal lid closing the opening.

In places where underground structures such as sewerage, water supply, electric power, gas, communication, etc. underground facilities and underground facilities are connected to the ground, a support frame that defines the opening leading to the underground structure and this support frame shall be supported. In some cases, an underground structure lid receiving frame set including a lid that closes an opening is installed. In this specification, a state in which the lid is supported by the receiving frame and the opening is closed (a state in which the lid is fitted into the receiving frame) is sometimes referred to as a closed state. Moreover, the lid receiving frame set for underground structures may be abbreviated as a lid receiving frame set.

Hydrogen sulfide or the like is generated in the above-described underground structure, especially in places where sewage is stagnant, such as sewage pipeline facilities, and a corrosive atmosphere is likely to occur. The lid and receiving frame are generally made of metal such as cast iron. Good anti-corrosion performance is required. For this reason, it has been proposed to provide an anti-corrosion coating film by electrostatically coating an epoxy resin-based powder coating or the like on the back surface of the lid or the exposed portion of the receiving frame (see, for example, Patent Document 1).

The lid and receiving frame are made of metal such as cast iron, and due to surface roughness, etc., there may be a gap between the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame, which are in surface contact when the lid is closed. likely to occur. As a result, there is a problem that the increased corrosive atmosphere enters between the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame, corroding the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame. Here, it is difficult to provide a uniform anti-corrosion coating on the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame. It will peel off. For this reason, it is currently difficult to prevent corrosion of the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame with the anticorrosion coating film described in Patent Document 1.

On the other hand, in order to prevent vibration, noise, rattling, etc., a lid receiving frame set has been proposed in which a packing is arranged between the lid body and the receiving frame (see Patent Documents 2 to 4, etc.).

JP 2015-045220 A JP-A-8-13527 JP-A-8-151650 Japanese Utility Model Laid-Open No. 6-35346

In the lid receiving frame sets described in Patent Documents 2 to 4, the packing collapses when the lid is closed, so that the gap between the lid body and the receiving frame is absorbed by the packing, thereby preventing vibration and the like. However, it cannot be said that the tightness between the packing and the cover or receiving frame is sufficient. In particular, when the packing deteriorates due to long-term use, a corrosive atmosphere tends to enter between the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame. Therefore, even in the lid receiving frame sets described in Patent Documents 2 to 4, it is difficult to stably prevent corrosion of the outer peripheral surface of the lid body and the inner peripheral surface of the receiving frame over a long period of time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lid support frame set for an underground structure which is devised to stably prevent corrosion of the outer peripheral surface of the lid body and the inner peripheral surface of the support frame over a long period of time. .

The lid receiving frame set for an underground structure of the present invention, which solves the above-mentioned objects, comprises a metal receiving frame defining an opening connected to the underground structure, and a metal lid supporting the receiving frame to close the opening. In a lid receiving frame set for underground structures comprising
The receiving frame has an inner peripheral surface inclined in a direction in which the inner diameter becomes narrower downward,
The lid body has an outer peripheral surface inclined in a direction in which the outer diameter becomes narrower downward,
At least one of the inner peripheral surface and the outer peripheral surface is provided with an anti-corrosion sheet,
The anti-corrosion sheet is made of one or more of synthetic rubber and plastic, and has a hardness of 60° to 100° and a thickness of 0.5 to 5.0 mm. Or, when the outer peripheral surface is in surface contact and a load is applied to the lid, the diameter of the receiving frame expands or the diameter of the lid decreases due to elastic deformation, or the diameter of the receiving frame expands and the lid due to elastic deformation. It is characterized by promoting the diameter reduction of.
According to another aspect of the present invention, there is provided a lid receiving frame set for an underground structure which solves the above-mentioned objects.
A lid receiving frame set for an underground structure comprising a metal lid that closes the opening by being supported by the receiving frame,
The receiving frame has an inner peripheral surface inclined in a direction in which the inner diameter becomes narrower downward,
The lid body has an outer peripheral surface inclined in a direction in which the outer diameter becomes narrower downward,
At least one of the inner peripheral surface and the outer peripheral surface is provided with an anti-corrosion sheet,
The anti-corrosion sheet is made of one or more of a rolled material or a thermal spray coating made of aluminum, zinc, stainless steel, nickel, chromium, or an alloy containing any of these as the main material, and has a thickness of 0.1 to 3.0 mm, and when the lid is closed, it is in surface contact with the inner peripheral surface or the outer peripheral surface, and when a load is applied to the lid, the diameter of the receiving frame is expanded or the lid is elastically deformed. It is characterized by facilitating diameter expansion of the receiving frame and diameter reduction of the lid by diameter reduction or elastic deformation.

Here, the receiving frame and the lid may be made of cast iron, for example. Further, the inclination angles of the inner peripheral surface and the outer peripheral surface are not particularly limited. For example, within the range of about 8° to 12°, the inclination angle may be the same, or the inclination angle of the inner peripheral surface may be slightly larger than the inclination angle of the outer peripheral surface. The inclination angle and the inclination angle of the outer peripheral surface may be different. Here, the angle of inclination refers to an angle of inclination with respect to a direction perpendicular to the upper surface of the lid which is horizontal with respect to the upper end surface of the receiving frame.

When a load is applied to the lid, the anti-corrosion sheet expands the diameter of the frame, reduces the diameter of the lid, or expands the diameter of the frame and reduces the diameter of the lid by elastic deformation. , material, hardness and thickness, etc. Whether the diameter of the frame expands, the lid contracts, or the diameter of the frame expands and the lid contracts due to elastic deformation depends on the frame and the lid. depends on the elastic modulus of In general, the diameter of the frame increases in many cases, but when the frame is designed to be rigid, the lid may decrease in diameter. In addition, the anti-corrosion sheet is not cut or cracked even by interference (contact) between the lid and the receiving frame during the opening and closing operation of the lid, and is scratched and the cast iron sheet in the lid and the receiving frame It is preferable to set the thickness such that the substrate is not exposed.

According to the lid receiving frame set for an underground structure of the present invention, when a load is applied to the lid body in the closed state, the anti-corrosion sheet causes the diameter of the receiving frame to expand or contract, or the diameter of the lid body to decrease. expansion of the diameter of the lid and contraction of the diameter of the lid are promoted. As a result, the so-called wedge effect is strengthened by the force of the receiving frame that has been elastically deformed and expanded in diameter, and the force of the cover that has been elastically deformed and reduced in diameter, to expand the diameter of the anticorrosion sheet. As a result, the adhesion of surface contact with the inner peripheral surface or the outer peripheral surface increases. This makes it difficult for a corrosive atmosphere to enter between the outer peripheral surface and the anti-corrosion sheet or between the inner peripheral surface and the anti-corrosion sheet even after long-term use. Corrosion of the surface can be stably prevented over a long period of time.

Here, the synthetic rubber is preferably NBR (nitrile rubber), CR (chloroprene rubber) or IIR (butyl rubber), and the plastic is preferably PP (polypropylene) or PVC (polyvinyl chloride) .

Furthermore, in the lid receiving frame set for an underground structure of the present invention, the anti-corrosion sheet may be provided on a lower portion of the inner peripheral surface or the outer peripheral surface.

By doing so, the surface contact between the anti-corrosion sheet and the lower portion of the inner peripheral surface or between the anti-corrosion sheet and the lower portion of the outer peripheral surface is further enhanced, and the outer peripheral surface and the inner peripheral surface are in close contact with each other. Surface corrosion can be prevented more effectively.

In the underground structure lid receiving frame set of the present invention, the anti-corrosion sheet may gradually become thicker toward the lower end .

This makes it easier to stop the rising corrosive atmosphere from entering at the lower portion of the inner peripheral surface or the outer peripheral surface, thereby more effectively preventing corrosion of the outer peripheral surface and the inner peripheral surface. be able to.

According to the present invention, it is possible to provide an underground structure lid receiving frame set that is designed to stably prevent corrosion of the outer peripheral surface of the lid body and the inner peripheral surface of the receiving frame over a long period of time.

(a) is a cross-sectional view of a lid receiving frame set that is an embodiment of the present invention, and (b) is a plan view of the lid receiving frame set shown in (a). (a) is an enlarged end view showing a portion where the cover body and the receiving frame are in surface contact in the circled portion A in FIG. 1(a). (b) is an end view showing the receiving frame extracted from (a). It is a figure which shows the 1st modification of the lid receiving frame set shown to Fig.2 (a). It is a figure which shows the 2nd modification of the lid receiving frame set shown to Fig.2 (a). (a) is a diagram for explaining Test 1 and Test 3, and (b) is a diagram for explaining Test 2. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1(a) is a cross-sectional view of a lid receiving frame set 10 that is an embodiment of the present invention, and FIG. 1(b) is a plan view of the lid receiving frame set 10 shown in FIG. 1(a). The cross-sectional view shown in FIG. 1(a) is a cross-sectional view taken along the line BB in FIG. 1(b). Moreover, the ground G is shown in FIG. 1(a), and the ground G is omitted in FIG. 1(b).

FIG. 1 shows a lid support frame set (underground structure lid support frame set) 10 that includes a lid body 2 and a support frame 3 that supports the lid body 2 . A sewer drain pipe, which is an underground facility, is buried at a predetermined depth from the ground surface, and a manhole is provided as an underground facility in the middle of the sewer drain pipe. Both sewage pipes and manholes are equivalent to underground structures. A manhole is a vertical hole that leads from a sewer drain pipe to the surface of the ground, using a framework made by stacking ready-made concrete moldings. The receiving frame 3 is provided on the frame and defines an opening H leading to a manhole which is an underground structure. The inside of this underground structure is in a corrosive atmosphere due to generated hydrogen sulfide and the like.

The cover 2 has a circular shape in a plan view for freely opening and closing an opening H leading to a manhole, which is an underground structure. The cover 2 shown in FIG. The lid body 2 and the receiving frame 3 shown in FIG. 1 are formed by casting, and are made of cast iron made of FCD700, for example. The lid body 2 and the receiving frame 3 may be made of iron other than cast iron, or may be made of metal other than iron. The lid body 2 includes a disk-shaped top plate portion 21, an annular wall portion 22 provided on the outer peripheral portion of the top plate portion 21 and surrounding the top plate portion 21, and a lid rib protruding downward from the back surface of the top plate portion 21. 23. An anti-corrosion film is formed by electrodeposition coating on the back surface of the top plate portion 21 and the lid rib 23 . An outer peripheral surface 221 (see FIG. 2), which will be described later in detail, is formed on the outer periphery of the annular wall portion 22 . A keyhole 211 for inserting an opening/closing tool is formed in the peripheral portion of the top plate portion 21 located on the lower side in FIG. A lock (not shown) is provided to keep the closed state. On the other hand, a hinge (not shown) for rotatably connecting the lid body 2 to the receiving frame 3 is provided at a position 180 degrees opposite to the lock (upper side in FIG. 1(b)).

As shown in FIG. 1, the receiving frame 3 includes a cylindrical frame body 31 formed in a ring shape in plan view, a flange portion 32 projecting outward from the lower end portion of the frame body 31, and a flange portion 32 provided on the upper surface of the flange portion 32. and frame ribs 33. The inner peripheral portion of the frame body 31 is provided with a ring-shaped stop portion 312 projecting inside the receiving frame 3 . When the lid body 2 slides down due to long-term use, the stopping part 312 abuts against the lower end of the annular wall part 22 of the lid body 2 to prevent further sliding down. An inner peripheral surface 311 (see FIG. 2) is formed on the upper side of the stop portion 312 in the inner peripheral portion of the frame main body 31, and an anti-corrosion sheet S (see FIG. 2) is provided on the inner peripheral surface 311. .

FIG. 2(a) is an enlarged end view showing a portion where the cover 2 and the receiving frame 3 are in surface contact in the circled portion A in FIG. 1(a). FIG. 2(b) is an end view showing the receiving frame 3 extracted from FIG. 2(a). In addition, in FIG.2(b), the example which provided the anti-corrosion sheet|seat S on the outer peripheral surface 221 of the cover body 2 is enclosed with the circle of a dashed-dotted line, and is shown.

As shown in FIG. 2( a ), the receiving frame 3 has an inner peripheral surface 311 , which is located above the stopping portion 312 in the inner portion of the frame body 31 and is inclined in a direction in which the inner diameter decreases downward. there is Further, the lid body 2 has an outer peripheral surface 221 on the outer periphery of the annular wall portion 22 that is inclined in a direction in which the outer diameter becomes narrower downward.

As shown in FIG. 2B, the inclination angle θ1 of the inner peripheral surface 311 of the receiving frame 3 is the same as the inclination angle θ2 of the outer peripheral surface 221 of the lid 2 (see the dashed-dotted circle) (for example, 8° ~9°). Further, an anti-corrosion sheet S is provided over the entire circumference of the inner peripheral surface 311 by adhesion or the like.

In this embodiment, the anti-corrosion sheet S is made of synthetic rubber NBR, and its hardness is set to 60° to 100°. Here, if the hardness of the anti-corrosion sheet S is less than 60°, the force of the load applied to the lid body 2 will be absorbed in the same way as the packing, promoting the diameter expansion of the receiving frame 3 and the diameter reduction of the lid body 2. difficult to do In addition, the thickness of the anti-corrosion sheet S is such that it does not break or break due to interference between the lid 2 and the receiving frame 3 during the opening and closing operation of the lid 2, and the cast iron in the lid 2 and the receiving frame 3 is scratched. It is set in the range of 0.5 to 5.0 mm from the viewpoint of the thickness that does not expose the substrate.

Further, the anti-corrosion sheet S is not limited to one made of NBR, but may be made of other synthetic rubber such as CR or IIR, or made of plastic such as PP or PVC. can be anything. Furthermore, a composite of these materials may be used. The anticorrosion sheet S made of synthetic rubber or plastic preferably has a hardness of 60° to 100° and a thickness of 0.5 to 5.0 mm, as in the case of NBR.

Furthermore, as the anti-corrosion sheet S, a wrought material or a thermal spray coating made of aluminum, zinc, stainless steel, nickel, chromium, or an alloy containing any of these as the main material can be employed. The thickness of the anti-corrosion sheet S when these wrought materials and thermal spray coatings are employed is preferably 0.1 to 3.0 mm.

As shown in FIG. 2(a), in the closed state, the outer peripheral surface 221 of the lid 2 and the anti-corrosion sheet S provided on the inner peripheral surface 311 of the receiving frame 3 come into surface contact with each other, and the lid 2 becomes the receiving frame. 3 supported. When a load is applied to the lid body 2 in this closed state, the anticorrosion sheet S expands the diameter of the receiving frame 3 (white arrow) or contracts the diameter of the lid body 2 (filled arrow) due to elastic deformation. Alternatively, the diameter expansion of the receiving frame 3 and the diameter reduction of the lid body 2 are promoted by elastic deformation. As a result, the so-called wedge effect is strengthened by the force of the receiving frame 3 whose diameter has been elastically deformed and expanded, and the force of the cover body 2 whose diameter has been elastically deformed and reduced, which tends to expand. , the surface contact with the outer peripheral surface 221 of the lid 2 is enhanced. This makes it difficult for a corrosive atmosphere to enter between the anti-corrosion sheet S and the outer peripheral surface 221 of the lid 2 even after long-term use, stably preventing corrosion of the outer peripheral surface 221 of the lid 2 for a long period of time. can do. In this embodiment, the inner peripheral surface 311 of the receiving frame 3 is prevented from being corroded by the anti-corrosion sheet S provided on the surface.

In addition, the place where the anticorrosion sheet S is provided is not limited to the inner peripheral surface 311 of the receiving frame 3. In FIG. It may be provided on the outer peripheral surface 221 . When this aspect is adopted, the surface contact between the anticorrosive sheet S and the inner peripheral surface 311 of the receiving frame 3 is enhanced, and even after long-term use, the anticorrosive sheet S and the inner peripheral surface of the receiving frame 3 are maintained. A corrosive atmosphere is less likely to enter between 311. However, since the outer peripheral surface 221 of the lid 2 has a keyhole 211 (see FIG. 1(b)) and the like, considering the workability of sticking the anticorrosive sheet S with an adhesive or the like, the anticorrosive sheet S cannot be attached to the receiving frame 3. is preferably provided on the inner peripheral surface 311 of the . Note that the anti-corrosion sheet S may be provided on both the inner peripheral surface 311 of the receiving frame 3 and the outer peripheral surface 221 of the lid body 2 .

Furthermore, as shown by encircling the two-dot chain line in FIG. 2(b), the wire W or the like may be inserted inside the anti-corrosion sheet S made of NBR or the like. According to this aspect, the load applied to the lid 2 can be easily transmitted, and the surface contact between the anticorrosion sheet S and the outer peripheral surface 221 of the lid 2 or the inner peripheral surface 311 of the receiving frame 3 can be further enhanced. can.

Next, a modification of the lid receiving frame set shown in FIGS. 1 and 2 will be described. In the modifications described below, differences from the embodiment shown in FIGS. 1 and 2 will be mainly described. , will be described with the reference numerals that have been used so far, and overlapping descriptions may be omitted.

FIG. 3 shows a first modification of the lid receiving frame set 10 shown in FIG. 2(a).

As shown in FIG. 3 , in the lid receiving frame set 10 of the first modified example, the anti-corrosion sheet S is provided on the lower portion of the inner peripheral surface 311 of the receiving frame 3 . According to the lid receiving frame set 10 of the first modified example, the surface contact between the anti-corrosion sheet S and the lower portion of the outer peripheral surface 221 of the lid body 2 is further enhanced to prevent the rising corrosive atmosphere from entering. , can be effectively prevented upstream thereof.

FIG. 4 is a diagram showing a second modification of the embodiment shown in FIG. 2(a).

As shown by encircling the dashed-dotted line in FIG. 4, the lid receiving frame set 10 of the second modification employs the anti-corrosion sheet S whose thickness t increases downward.

This makes it easier to stop the rising corrosive atmosphere from entering at the lower portion of the anticorrosion sheet S and the outer peripheral surface 221 of the lid 2, and the corrosion of the outer peripheral surface 221 of the lid 2 is more effectively prevented. can be prevented.

Next, tests performed on the embodiments shown in FIGS. 1 to 4 will be described along with comparative examples.

Two lid receiving frame sets were prepared in which the diameter of the upper end of the inner peripheral surface 311 of the receiving frame 3 and the diameter of the upper end of the outer peripheral surface 221 of the lid body 2 were both 630 mm. The material of the receiving frame 3 was FCD600, and the material of the lid 2 was FCD700. Also, the lid body 2 used conformed to the Japan Sewage Works Association standard JSWAS G-4. Of these two sets of receiving frames, the receiving frame 3 of one of the lid receiving frame sets 10 has its inner peripheral surface 311 shaved so that the diameter of the upper end of the inner peripheral surface 311 is 633 mm. A 1.5 mm anti-corrosion sheet S was provided. As the anticorrosion sheet S, an NBR sheet having a hardness of 70° was used. As a result, an example was obtained in which the diameter of the upper end of the anticorrosive sheet S of the receiving frame 3 was 630 mm. The other receiving frame set 10' was not provided with the anti-corrosion sheet S and was used as a comparative example. Then, Tests 1 to 3 were carried out for Examples and Comparative Examples.

FIG. 5A is a diagram for explaining Test 1 and Test 3. FIG.

(Test 1) With the lid closed, the loading plate P installed on the lid 2 is 70 kN as the actual weight, which is the load when the trailer passes, and 3 times the JSWAS G-4 standard of the Japan Sewage Works Association. Measure the deformation of the receiving frame 3 during loading when two types of loads of 210 kN, which are considered to be test loads with a safety factor of 1, are applied once each, and the deformation of the receiving frame 3 during loading when they are applied 10 times. bottom. As shown in FIG. 5( a ), the measurement points are four points at 90° intervals starting from the point where the hinge is provided, which is 180° opposite to the lock provided on the back side of the keyhole 211 . (M1 to M4), and a displacement meter was installed at a position 15 mm below the upper end of the receiving frame 3 and measured.

Table 1 shows the displacement of the receiving frame 3 when a load of 70 kN is applied once, and Table 2 shows the displacement of the receiving frame 3 when a load of 210 kN is applied once. Table 3 shows the displacement of the receiving frame 3 when a load of 70 kN is applied ten times, and Table 4 shows the displacement of the receiving frame 3 when a load of 210 kN is applied ten times. In Tables 1 to 4, minus indicates a diameter-enlarged value of the receiving frame 3, and plus indicates a diameter-reduced value of the receiving frame 3.

FIG. 5B is a diagram for explaining Test 2. FIG.

(Test 2) It is known from past experimental results that the displacement around the loading plate P is large. Therefore, as shown in FIG. 5(b), the same load as in Test 1 was applied to a total of four locations around the loading plate P, namely two locations on the hinge side M5 and M5 and two locations on the lock side M6 and M6. The deformation of the receiving frame 3 during loading when each was applied once and the deformation of the receiving frame 3 during loading when being applied 10 times were measured. Note that the measurement location was the location where the frame rib 33 was provided.

Table 5 shows the displacement of the receiving frame 3 when a load of 70 kN is applied once, and Table 6 shows the displacement of the receiving frame 3 when a load of 210 kN is applied once. Table 7 shows the displacement of the receiving frame 3 when a load of 70 kN is applied ten times, and Table 8 shows the displacement of the receiving frame 3 when a load of 210 kN is applied ten times. In Tables 5 to 8, minus indicates a diameter-expanded value of the receiving frame 3, and plus indicates a diameter-reduced value of the receiving frame 3.

As is clear from the results of Tests 1 and 2, the diameter expansion of the receiving frame 3 is greater in the example provided with the anticorrosion sheet S than in the comparative example without the anticorrosion sheet S. It is understood that In other words, the anti-corrosion sheet S accelerates the diameter expansion of the receiving frame 3 due to elastic deformation when a load is applied to the lid body 2 . In this respect, even in the embodiment in which the anticorrosion sheet S is provided, the receiving frame 3 is elastically deformed, and it can be seen that the packing is different from the packing that absorbs the elastic deformation and fills the gap. In the example, elastic deformation of the receiving frame 3 occurs even when a low load of 70 kN is applied. Therefore, it can be seen that it is possible to generate bite force between the lid body 2 and the receiving frame 3 by repeatedly applying a light load such as a light vehicle or a two-wheeled vehicle.

(Test 3) In the closed state, two types of loads of 70 kN and 210 kN were applied once to the loading plate P installed on the lid 2, and the settlement amount of the lid 2 during loading, The sinking amount of the lid body 2 during loading when the load was applied 10 times was measured. As in Test 1, measurement was performed at four locations (M1 to M4) shown in FIG.

Table 9 shows the amount of settlement of the lid 2 when a load of 70 kN is applied once, and Table 10 shows the amount of settlement of the lid 2 when a load of 210 kN is applied once. Table 11 shows the amount of settlement of the lid 2 when a load of 70 kN is applied ten times, and Table 12 shows the amount of settlement of the lid 2 when a load of 210 kN is applied ten times.

As is clear from the results of Test 3, the cover body 2 sinks more in the example provided with the anticorrosion sheet S than in the comparative example without the anticorrosion sheet S. . That is, when a load is applied to the lid body 2, the anti-corrosion sheet S accelerates the diameter expansion of the receiving frame 3, the diameter reduction of the lid body 2, or the diameter expansion of the receiving frame 3 and the diameter reduction of the lid body 2 due to elastic deformation. It is. Considering this point, while the receiving frame 3 of the comparative example is supported by a partially concentrated load due to the surface line points, in the example, the anticorrosion sheet S provides an even load, and the lid body 2 and the receiving frame 3 are supported. It is presumed that the adhesion of is high.

According to the lid receiving frame set 10 described above, corrosion of the outer peripheral surface of the lid body and the inner peripheral surface of the receiving frame can be stably prevented for a long period of time.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, in the above-described embodiment, the inclination angle θ1 of the inner peripheral surface 311 of the receiving frame 3 and the inclination angle θ2 of the outer peripheral surface 221 of the lid body 2 are set to be the same. The inclination angle θ1 of 311 may be larger than the inclination angle θ2 of the outer peripheral surface 221 of the lid 2 . By adopting this mode, it is possible to further enhance the adhesion of surface contact between the anticorrosion sheet S and the lower portion of the outer peripheral surface 221 of the lid 2 .

In addition, even if the constituent elements are included only in the descriptions of the embodiments and modifications described above, the constituent elements may be applied to the embodiments and other modifications.
(Appendix 1) Other lid support frame sets for underground structures are
An underground structure lid receiving frame set comprising: a metal receiving frame that defines an opening connected to an underground structure; and a metal lid that closes the opening by being supported by the receiving frame,
The receiving frame has an inner peripheral surface inclined in a direction in which the inner diameter becomes narrower downward,
The lid body has an outer peripheral surface inclined in a direction in which the outer diameter becomes narrower downward,
At least one of the inner peripheral surface and the outer peripheral surface is provided with an anti-corrosion sheet,
When the lid is closed, the anti-corrosion sheet is in surface contact with the inner peripheral surface or the outer peripheral surface, and when a load is applied to the lid, the diameter of the receiving frame is expanded or the diameter of the lid is reduced due to elastic deformation. Alternatively, it is characterized by facilitating diameter expansion of the receiving frame and diameter reduction of the lid by elastic deformation.
(Appendix 2) In the lid receiving frame set for an underground structure described in Appendix 1, the anticorrosion sheet may be thicker toward the bottom.

10 Lid Receiving Frame Set 2 Lid 21 Top Plate 211 Keyhole 22 Annular Wall 221 Outer Peripheral Surface 23 Lid Rib 3 Receiving Frame 31 Frame Main Body 311 Inner Peripheral Surface 312 Stopper 32 Flange 33 Frame Rib G Ground H Opening S Anticorrosion Sheet W wire

Claims (4)

a metal framing defining an opening leading to an underground structure;
A lid receiving frame set for an underground structure comprising a metal lid that closes the opening by being supported by the receiving frame,
The receiving frame has an inner peripheral surface inclined in a direction in which the inner diameter becomes narrower downward,
The lid body has an outer peripheral surface inclined in a direction in which the outer diameter becomes narrower downward,
At least one of the inner peripheral surface and the outer peripheral surface is provided with an anti-corrosion sheet,
The anti-corrosion sheet is made of one or more of synthetic rubber and plastic, and has a hardness of 60° to 100° and a thickness of 0.5 to 5.0 mm. Or, when the outer peripheral surface is in surface contact and a load is applied to the lid, the diameter of the receiving frame expands or the diameter of the lid decreases due to elastic deformation, or the diameter of the receiving frame expands and the lid due to elastic deformation. A lid receiving frame set for an underground structure, characterized in that it promotes the diameter reduction of the underground structure. a metal framing defining an opening leading to an underground structure;
A lid receiving frame set for an underground structure comprising a metal lid that closes the opening by being supported by the receiving frame,
The receiving frame has an inner peripheral surface inclined in a direction in which the inner diameter becomes narrower downward,
The lid body has an outer peripheral surface inclined in a direction in which the outer diameter becomes narrower downward,
At least one of the inner peripheral surface and the outer peripheral surface is provided with an anti-corrosion sheet,
The anti-corrosion sheet is made of one or more of a rolled material or a thermal spray coating made of aluminum, zinc, stainless steel, nickel, chromium, or an alloy containing any of these as the main material, and has a thickness of 0.1 to 3.0 mm, and when the lid is closed, it is in surface contact with the inner peripheral surface or the outer peripheral surface, and when a load is applied to the lid, the diameter of the receiving frame is expanded or the lid is elastically deformed. A lid receiving frame set for an underground structure, characterized in that it promotes diameter expansion of the receiving frame and diameter reduction of the lid by diameter reduction or elastic deformation. 3. The lid receiving frame set for an underground structure according to claim 1, wherein the anti-corrosion sheet is provided on a lower portion of the inner peripheral surface or the outer peripheral surface. 4. The lid receiving frame set for an underground structure according to claim 1, wherein said anti-corrosion sheet gradually becomes thicker toward its lower end .

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