JP3325872B2 - Concrete composite cast iron lid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an electric wire joint groove (CC).
B) The present invention relates to a concrete composite cast iron lid using concrete and cast iron for a lid for an information box, a lid for a manhole, and the like.

[0002]

2. Description of the Related Art As this kind of the related art, there is known a structure as shown in FIG . That is, the lid 1 is composed of a frame 2, a reinforcing bar 3, a reinforcing bar holding portion 4, concrete and a top tile (not shown), and the like.
The frame 2 is made of a steel plate, has a substantially L-shaped cross section, and has a predetermined lid size, for example, a rectangular shape. The reinforcing bar 3 is composed of an upper reinforcing bar 3a and a lower reinforcing bar 3b, each having a round bar-shaped reinforcing bar member 5 joined in a lattice shape, and an end portion of the reinforcing bar member 5 provided on the frame 2. Reinforcing bar holder 4
Is held in. The rebar holding part 4 is formed by bending a round bar-shaped member similar to the rebar member 5 into an L-shape, and is attached to the inside of the frame 2 by welding. The rebar holding member 4 and the rebar member 5 are also welded. Then, the inside of the frame 2 is filled with concrete, and for example, tiles are installed on the upper surface to complete the process.

[0003]

The conventional lid described above secures strength with the reinforcing steel 3 and concrete,
It is inconvenient to handle because it is thick and heavy. Further, since the frame 2 and the reinforcing bar 3 constituting the outer periphery are made of steel, they are easily corroded, and there is a problem in durability. In addition, it takes time to assemble and attach the reinforcing bar 3, and since the attachment is welding, distortion is likely to occur, and the accuracy is not good. In particular, in the use state, an irregular gap is formed between the lid and the receiving frame, so that the appearance is not preferable, the commercial value is inferior, and rainwater easily flows in. Accordingly, an object of the present invention is to provide a lid that is excellent in durability, easy to manufacture, and excellent in appearance.

[0004]

The present invention provides a cover formed in a plate-like body that closes a predetermined opening, comprising: an outer peripheral portion; a concrete portion provided inside the outer peripheral portion; It has a reinforcement portion, and the outer peripheral portion and the reinforcing portion is Ri integral structure der cast iron, moreover, the peripheral portion
Has an inner step that forms an upward facing surface
Having a portion of the formed configuration, and the reinforcing portion is neutral
It is provided at a position below the axis, and its upper surface is on the lower side inside
You wherein the step and is substantially flush.

[0005] Since a portion corresponding to the conventional frame and the reinforcing bar holding portion and a portion corresponding to the reinforcing bar are formed as an integrated structure made of cast iron, it is possible to easily obtain a high-precision one which does not require welding, has little distortion and has little distortion. Can be manufactured. Further, it is hardly corroded and has excellent durability as compared with conventional steel products.

[0006] In the means, not good that a structure in which the reinforcing portion has a plurality of holes provided across the inner space penetrating in the up and down of the outer peripheral portion. In this configuration, when the reinforcing portion is completely buried in the concrete portion, the lower concrete portion of the reinforcing portion is connected to the upper concrete portion via the concrete portions in many holes, and the concrete portion is It is difficult to fall off when cracks occur.

[0007] In the means, the reinforcing portion is not good that a structure which is formed in a lattice shape. In this configuration, the vertical and horizontal members of the lattice are integrally provided within the same thickness range on the same plane, so that they are excellent in strength and can be formed relatively thin.

[0008] In the above means, some of the portions corresponding to the bars of the portion formed in the lattice shape, which extend linearly and have both ends reaching the outer peripheral portion, are better than others. vertical have good that a structure which is formed a thickness dimension larger. In this configuration, the key points of the lid can be made to have a large moment of inertia, so that the deflection on the top surface of the lid can be reduced, the concrete strain near the bottom surface of the lid can be reduced, and the tensile stress can be reduced. Can be suppressed. Therefore, the concrete near the lower surface of the lid is not easily cracked by the load acting on the upper surface.

[0009] In the means, the reinforcing portion is not good that a structure is provided in a position subjected to the action tensile against the load applied to the upper surface of the plate-like body. In this configuration, the position receiving the pulling action is below the position corresponding to the neutral axis of the beam. Although a tensile force is applied when a downward load is applied to the upper surface of the cover, the elongation is smaller than that of a conventional reinforcing bar, and therefore, cracks are not easily generated in the concrete near the lower surface.

[0010] In the means, the cross-sectional shape of the portion corresponding to the crosspiece of the lattice-shaped part, not good that a structure is an enlarged shape downward. With this configuration, it is difficult for concrete to fall when cracks occur. In this case, the reinforcing portion has a slightly complicated shape, but since casting is possible, manufacturing is not so difficult.

In the above means, the outer peripheral portion may be provided with a step such that a lower surface is formed midway in the thickness direction of the plate-like body on the outer peripheral surface, and the lower surface is a supported portion supported by a lid receiving frame. not good that the. In this configuration, when the lid is mounted on the lid receiving frame having an opening into which the outer peripheral portion is fitted and the opening is closed, the fitting length dimension of the outer periphery fitted into the outer peripheral portion of the lid, that is, the dimension of the outer peripheral lid thickness direction is changed. If it is long, opening and closing tends to be difficult. By providing the step to provide the supported portion, the fitting length of the outer peripheral portion is substantially shortened, so that the lid can be easily opened and closed. And, by providing the step, it is possible to prevent the thickness of the outer casting from easily becoming excessively thick.

[0012] In the above means, the outer peripheral portion is formed by inclining an outer surface from the upper side to the lower inner side, and is formed by inclining the inner surface to the lower inner side substantially in parallel with the outer surface to a part of the way from the upper end to the lower side. An inner step which forms an upward surface in the middle is formed by inclining downward from the inner step to the lower end, and the inclination is substantially equivalent to a draft angle of a model in mold production. configuration and to is not good at. In this configuration, while maintaining the draft angle of the model in the mold molding, due to the presence of the inner step, this acts as a support for the concrete part, and the inclination of the inner surface exhibits a tapered fitting state with the concrete part,
A stronger connection between the outer peripheral portion and the concrete portion is obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This concrete composite cast iron lid is 10,
It comprises an outer peripheral portion 11, a reinforcing portion 12, a concrete portion 13 filled inside, and a tile 14 as a surface material.
The outer peripheral portion 11 is formed in a rectangular shape in this embodiment,
The portion 11a that forms one of the two opposing sides is shown in FIG.
As shown in (a), (c), (d), and FIG. 2 (b), a portion 11b having a width in the vertical direction corresponding to the total thickness of the lid and constituting the other two sides is provided. , FIGS. 1 (a), (b),
As shown in FIG. 2A, a stepped portion having a shape in which the lower side is depressed inward by a predetermined width is provided in the middle of the thickness direction, and this stepped portion is the supported portion 15. Each of the portions 11a and 11b is formed such that the outer surface is inclined from the upper side to the lower side to the inside of the mold at a draft angle, and the inner surface below the position connected to the reinforcing portion 12 described later is inclined downward to the outside at the draft angle of the mold. The upper inner surface is provided in parallel with the outer surface to form a predetermined thickness, and the inner step 23 is formed inside.

The reinforcing portion 12 is formed in a lattice shape, and has a rectangular hole 18 formed by a vertical portion 16 and a horizontal portion 17 thereof. When the lattice-shaped reinforcing portion tries to bend downwardly by a load acting on the upper surface in a state where the supported portions 15 at the upper and lower ends in FIG. 1B are supported, a tensile force is generated. It is in the working position. That is, it is located below the neutral axis. The frame portion 11 and the reinforcing portion 12 are, for example, FCD
It is integrally formed by 700-2. As shown in FIGS. 2A and 2B, concrete 13 is filled inside the frame 11 to embed the reinforcing portion 12, and the tile 1 is provided on the upper surface.
4 is installed to complete the lid 10. In addition, FIG.
Reference numeral 19 in (d) denotes a key attaching portion. FIG.
24 in (a) is a receiving frame made of cast iron.

In this concrete composite cast iron lid 10, since the outer peripheral portion 11 and the reinforcing portion 12 are integrally formed of cast iron, the reinforcing bars are not assembled or welded as in the conventional case.
It is easy to manufacture, and particularly easy to manufacture with high precision. Therefore, there is no occurrence of irregular gaps with the lid receiving frame, the appearance is good, the corrosion resistance is excellent, and the durability is good. Regarding this durability, reinforced concrete has been used for many years, and the salt contained in the sand of the concrete material causes corrosion of the reinforcing steel, or concrete reacts with oxygen in the air to neutralize from alkaline and adversely affect the reinforcing steel. Giving and dropping concrete has become a social problem. With respect to such a problem, the concrete composite cast iron lid is definitely more advantageous than a concrete lid using a conventional steel material. In addition, since the outer peripheral portion 11 and the reinforcing portion 12 are integrated, the required strength is secured and the thickness of the lid can be reduced. Further, providing the stepped portion as the supported portion 15 not only facilitates opening and closing of the lid, but also provides a reinforcing structure for the outer peripheral portion 11. Strength can be secured. In addition, since the lid can be manufactured with high precision, the cast iron receiving frame 24 can be easily adjusted in height as the lid receiving frame.
This makes the on-site construction work much easier than the prior art. In addition, the configuration of the inner step 23 serves as a support for the concrete portion 13 due to the presence of the inner step 23 while securing the draft of the model in the mold forming. In this state, when a load is applied to the upper surface of the lid, the concrete portion 13 is pushed in, and acts to form a stronger connection state. For this reason, the concrete composite cast iron lid can be provided at a sufficiently low total cost as compared with a conventional concrete lid using a steel outer frame and a steel bar.

In the above-described embodiment, a configuration in which the supported portions 15 are provided at both ends of the rectangular lid is shown. However, this is a configuration in which a plurality of lids are arranged so as to close a large and narrow opening. In the case where the opening is closed with only one sheet, a configuration in which a step is provided on the entire outer periphery may be adopted. Further, in the above embodiment, the lid is shown as a rectangular lid, but other shapes such as a circle may be used.

Further, as another embodiment of the present invention, as shown in FIG. 3A, a portion corresponding to a bar of a lattice-shaped portion as the reinforcing portion 12, that is, a straight portion of the vertical portion 16 is extended. Two of the portions reaching the outer peripheral portion 11 are formed so as to have a larger thickness dimension than the other vertical portions 16 as shown in FIG. Such a configuration may be increased or decreased in number, applied to the horizontal portion 17, or applied to the vertical portion 16 and the horizontal portion 17 in some cases. As a result, the second moment of area of the concrete composite cast iron lid 10a is increased, and the deflection of the lid when a load acts on the upper surface of the lid can be reduced. Therefore, the concrete part 13 on the lower surface of the lid (not shown)
And the generation of tensile stress can be suppressed to a small extent, and cracking of the concrete portion on the lower surface of the lid can be suppressed. In FIG. 3A, the same parts as those of the above embodiment are indicated by the same reference numerals.

Although not particularly described in the above embodiment, the cross-sectional shapes of the portions corresponding to the bars of the lattice-like portion, that is, the vertical portions 16 and the horizontal portions 17 are denoted by 21 in FIG. As shown, a trapezoidal shape spreading downward is preferred. This makes it difficult for the concrete to fall off. Also,
By making the corners of the cross section round as shown in the figure, the easiness of cracking of the concrete can be reduced.

[0019]

According to the present invention , there can be easily produced a high-precision one which does not require welding, has a small distortion and is less susceptible to corrosion and has excellent durability as compared with a conventional steel-made one. The effect which can provide is produced.

[Brief description of the drawings]

1A and 1B show a portion excluding a concrete part and a tile according to an embodiment of the present invention, wherein FIG. 1A is a plan view, FIG. 1B is a sectional view taken along line BB of FIG. 1A, and FIG. , (D) is (a)
It is AA sectional drawing of.

FIG. 2 is a partially enlarged view of the embodiment, and FIG.
FIG. 1B is an enlarged cross-sectional view corresponding to the portion of FIG.
It is a sectional enlarged view corresponding to the portion of (d).

3A and 3B show another embodiment of the present invention, in which FIG. 3A is a cross-sectional view corresponding to FIG. 1D, which is a modification of the reinforcing portion, and FIG. It is a cross-sectional enlarged view of a horizontal part.

FIG. 4 shows an example of a conventional concrete composite lid,
(A) is a plan view, (b) is a CC sectional view of (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Concrete composite cast iron lid 11 Outer peripheral part 12 Reinforcement part 13 Concrete part 14 Tile 15 Supported part 16 Vertical part 17 Horizontal part 18 Hole 20 Vertical part 21 Vertical part or horizontal part 23 Inner step

──────────────────────────────────────────────────続 き Continued on the front page (73) Patent holder 391034499 Tsurumi Concrete Co., Ltd. 3-104-4 Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa (73) Patentee 592005825 Sato Iron Works Co., Ltd. 3 Nihonbashi-hamacho, Chuo-ku, Tokyo Chome 36-2 (72) Inventor Keiji Hakusan 403 Yoshimi, Otsu-ku, Himeji-shi, Hyogo Prefecture Inside the Himeji Nishi Plant Co., Ltd. 72) Inventor Satoshi Yoshida 403 Yoshimi, Otsu-ku, Himeji-shi, Hyogo Pref. Inside the Himeji-Nishi Plant, (56) References JP-A-8-60686 (JP, A) JP-A-10-131275 (JP, A) 52-136462 (JP, U) Fully open 1979-511571 (JP, U) Fully open 1-75160 (JP, U) Fully open 63-1938 (JP, U) (58) Fields investigated (I) nt.Cl. ⁷ , DB name) E02D 29/14

Claims (1)

(57) [Claims] 1. A lid formed in a plate-like body for closing a predetermined opening, the lid having an outer peripheral portion, a concrete portion provided inside the outer peripheral portion, and a concrete reinforcing portion,
And a reinforcing portion and the peripheral portion, Ri integral structure der cast iron, moreover, the peripheral portion, the inner so as to form an upward surface
A portion having a configuration in which side steps are formed in two steps on the inner surface, and the reinforcing portion is provided at a position below a neutral axis.
A concrete composite cast iron lid, wherein an upper surface thereof is substantially flush with a lower inner step .