JPH05112957A - Manhole cover for snowy district and its production - Google Patents

Abstract

PURPOSE:To prevent heat lose and keep warm, by constituting a manhole cover by a three-layer structure of a castiron outer cover, a heat-insulating layer having a specified thickness provided at the rear face of the outer cover, and an inner cover made of FRP provided at the rear face of the heat-insulating layer to coat the layer. CONSTITUTION:An outer castiron cover 1 is formed as a flat cap, when viewed from the front, having a slightly curved face at the top thereof to loosely fit to the opening ring 101 installed at the peripheral edge of the manhole opening 100. And an inner cover 3 is made of FRP materials and it is formed as a cap having an appropriate size so that the outer peripheral plate 3a is fit closely to the inner face of side face plate of the outer cover 1 outer periphery. And a foaming heat-insulating material is filled as a moulding material in the charging space 2a defined between the outer cover 1 and the inner cover 3 to make a foaming heat-insulating layer 2 by foaming and curing thereof and combine the outer cover 1, the heat-insulating layer 2, and the inner cover 3 together with each other as a unit. In this way, the heat-insulating effect can be stably kept for a long time due to the heat-insulating layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manhole cover for a snowy area and a method for manufacturing the same.

[0002]

2. Description of the Related Art A manhole cover made of metal or concrete is heated by warm gases generated in the manhole, and the frozen snow on the manhole cover is melted to form a depression. These dents may cause unexpected slipping of tires (tires of a running vehicle) resulting in slipping and tire slipping, which could cause the steering wheel to be picked up or cause your feet to slip while walking and cause you to fall. It is a dangerous place. Conventionally, as a means for avoiding the above-mentioned danger, JP-A-63-297629
The manhole cover described in the official gazette and Japanese Utility Model Laid-Open No. 2-132747 is known. The former is one in which a foam heat insulating material is integrated on the back surface of the manhole cover, and the latter is one in which an inner heat insulating plate formed by covering foam plastic with urethane resin is fixed to the back surface of the manhole cover.

[0003]

However, in the former case, the initial adiabatic effect is caused by the fact that it is attacked by the gas components such as ammonia, methane gas, nitrogen gas, hydrogen sulfide, etc. generated in the manhole and causes a chemical change. Can't last. Since the latter covers the back surface of the manhole cover with a urethane resin, it can be expected to have a slightly longer thermal insulation effect than the former, but above all, the urethane resin has excellent weather resistance and flame retardancy. On the other hand, it is not stable in terms of contact resistance against the above-mentioned gas components, and therefore, it is not satisfactory in maintaining the heat insulating effect for a long period of time.

The present invention has been made in view of the conventional circumstances, and an object of the present invention is to provide a cover for a manhole for a snowy area and a method for manufacturing the same, which exhibits a particularly excellent effect of sustaining heat insulation. is there.

[0005]

Means for Solving the Problems The inventors of the present invention are required to have strength, electrical insulation, light weight, thermal expansion, weather resistance, and resistance to generated gas, and heat resistance that are essential for snowy areas. As a result of diligent research into providing a heat insulating layer on the back surface of the manhole cover (casting cover), when satisfying each of those properties, F
We have found that coating the heat insulating layer with an RP material is effective, and arrived at the present invention. That is, the present invention is a cast outer lid,
The gist is that it has a three-layer structure of a heat insulating layer of a desired thickness applied on the back surface of the outer lid and an FRP inner lid applied on the back surface of the heat insulating layer to cover the heat insulating layer, Further, the back surface of the cast outer lid is covered with an FRP inner lid to form a filling space for the heat insulating layer between the outer lid and the inner lid, and the filling space is filled with a foaming heat insulating material. The idea is to combine the three in one.

[0006]

According to the above technical means, the following actions are achieved. (Claim 1) The heat insulating layer applied to the back surface of the casting lid is FRP.
By covering with the inner lid made of, the heat insulating layer exhibited stable heat insulating effect durability for a long period of time. It is presumed that this is because the FRP inner lid described above has its own touch resistance and heat resistance and protects the heat insulating layer from gas components generated in the manhole. (Claim 2) The molding material for the foamable heat insulating layer to be filled is
At the time of foaming and curing, it is firmly adhered to the casting lid and the inner lid of the FRP product to integrally bond the three.

[0007]

Since the present invention is constructed as described above, it has the following advantages. (Claim 1) It is possible to newly provide a lid for a snowfall manhole having a cross-sectional structure that is excellent in heat insulation durability and is not affected by generated gas. (Claim 2) The casting lid is covered with a molding die, the molding material for the foamable heat insulating layer is filled to mold the heat insulating layer, and then the molding die is released from the mold to line the FRP material. As compared to the method used, the inner lid of the FRP product also serves as a molding die, which makes the manufacturing extremely simple. Therefore, the manufacturing process can be simplified, the facility cost can be reduced, and the manhole cover can be provided at low cost.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. 1 and 2 show an embodiment of claim 1, and FIG. 3 shows an embodiment of claim 2. First, a description will be given based on FIGS. 1 and 2.

The cover A of the snowhole manhole includes an outer cover 1 made of casting, an inner cover 3 made of FRP, and a heat insulating layer (referred to as a foaming heat insulating layer) 2 sandwiched between the both covers 1, 3. It is composed of a three-layer structure.

The outer cover 1 made of cast metal has a flat cap shape with a gently sloping curved upper surface in a front view, and is loosely fitted to a mouthpiece 101 provided around an open edge of a manhole opening 100 provided on a road or the like. A holding port (not shown) that rotatably engages with the base 101 and a lifting operation part (not shown) that is formed in a flat area of about 30 mm and that faces the center. Notch 10 is formed.

The inner lid 3 has strength, electrical insulation, light weight,
An FRP material (unsaturated polyester resin, glass fiber) having various properties such as low thermal expansion property, weather resistance, and resistance to generated gas, heat resistance, etc.
A substantial shape in which the outer peripheral plate 3a is formed into a cap shape such that the outer peripheral plate 3a is closely fitted to the inner surface, and the portion excluding the portion to be mounted on the base 100 bulges outward (downward). Is formed in.

The foamable heat insulating layer 2 is composed of a foamable heat insulating material such as hard polyurethane foam, and the molding material (the same amount of two liquids is filled in the filling space 2a formed between the outer lid 1 and the inner lid 3). Polyurethane liquid mixed and stirred) is filled, foaming,
After hardening, the three parts are integrally combined to form a layer between the outer lid 1 and the inner lid 3, and the substantial shape except for the portion to be mounted on the base 101 is slightly thickened. It has become. This foamable heat insulating layer 2 is composed of the cast outer lid 1 and F
It has the property of exhibiting extremely strong adhesive force to both of the inner lid 3 made of RP and the property of excellent heat insulation, and functions as an intermediate material that indirectly joins the upper and lower members 1, 3 together. is doing.

The lid A of the snowhole manhole thus formed in the three-layer structure is used by forming a keyhole 11 at a desired position in a subsequent process and attaching other necessary metal fittings. It

Therefore, the lid A of the manhole for snowfall according to the present embodiment has a strong adhesive force to the cast outer lid 1 and the FRP inner lid 3 of the hard polyurethane foam forming the foaming heat insulating layer 2 so that it can be applied to three parties. The FRP inner lid 3 has a sandwich structure that is firmly and integrally connected, and has a heat insulating property that is not affected by various warm gases generated in the manhole.
Lasts with the function of.

By the way, the reason why the rigid polyurethane foam is firmly adhered to the cast outer lid 1 and the FRP inner lid 3 is that the urethane resin contained functions as a universal adhesive and the composition of the both lids 1 and 3 is large. It is presumed that it is due to organic binding to the components.

Next, the manufacturing method shown in FIG. 3 will be described.
Reference numeral 4 is a clamp, and 5 is a molding material 20 for the foam insulation layer 2
It is a filling device for filling 0.

First, the casting outer cover 1 described in claim 1 and the FRP product inner cover 3 are fitted to each other to form a filling space 2a for the foamable heat insulating layer 2. In addition, a gas vent hole 3b is previously formed at a desired portion of the inner lid 3 made of an FRP product.
And the injection hole 3c of the molding material 200 is opened. Then, as shown in FIG. 3, the outer lid 1 and the inner lid 3 are clamped by clamps 4 and held upside down. A variable volume type container 5a which is made of a flexible material and stores the molding material 200 in that state
The supply hose 5b of the filling device 5 including the supply hose 5b is inserted into the injection hole 3c, and a gripping force is applied to the container 5a to pour an appropriate amount of the molding material 200 into the filling space 2a. It is manufactured by releasing the clamp 4 after a predetermined time has passed (after foaming and curing). The vent hole 3b and the injection hole 3c are FR in the post work.
The P material is lined to fill the holes.

The feature of this embodiment is that the inner lid 3 which is an FRP product is also used as a die for forming the heat insulating layer, and as a result, the inner lid 3 is attached and detached by the forming die (not shown) and the subsequent process.
It is possible to easily integrate the cast outer lid 1, the foamable heat insulating layer 2, and the FRP inner lid 3 without requiring any layering work (hand lay-up method or the like).

The filling device 5 described above is not limited to the one for artificially injecting the molding material, but it is of course free to adopt a means for mechanically injecting the molding material. In this case, it can contribute to the simplification of the manufacturing work.

[Brief description of drawings]

1 is a perspective view of an embodiment of claim 1. FIG.

FIG. 2 is an enlarged vertical sectional view showing a usage state of FIG.

FIG. 3 is a longitudinal sectional view showing a state in which a molding material is filled in the embodiment of claim 2;

[Explanation of symbols]

1: Outer cover made of casting 2: Heat insulation layer 3: Inner cover made of FRP A: Manhole cover for snowfall area

Claims (2)

[Claims] 1. An outer lid made of cast metal, a heat insulating layer having a desired thickness applied to the back surface of the outer lid, and an FRP inner lid applied to the back surface of the heat insulating layer to cover the heat insulating layer. A manhole cover for a snowy area, which is characterized by having a three-layer structure. 2. An outer lid made of casting is covered with an inner lid made of FRP to form a filling space for the heat insulating layer between the outer lid and the inner lid, and a foaming heat insulating layer is formed in the filling space. Fill with material 3
A method of manufacturing a manhole cover for a snowy area, characterized by integrally joining persons.