JPH0510035Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Industrial application field) This invention is mainly used for underground water supply,
Covers installed at the entrances and exits of underground structures such as manholes and handholes installed at the connections of gas, electricity, communication piping and wiring, and valve cases that house various valves and fire hydrants attached to these,
This particularly concerns rectangular lids.

(Prior Art) Conventionally, cast iron covers have been attached to the above-ground openings of underground structures such as manholes and various valve casings in order to inspect and operate the contents stored inside. These facilities are often installed on roads, and because they are rectangular, they tend to rattle when pebbles get caught between the lid and the receiving frame, causing noise. occurs.
For this reason, divide the rectangular lid into two diagonally,
Noise has been prevented by providing legs supported by a receiving frame on each top and forming a rectangular shape by forming a set of two triangular lid plates supported at three points.

(Problems to be solved by the invention) As mentioned above, when using a rectangular lid for the lid of an underground structure, a combination of two right-angled triangular lid plates made by cutting a rectangle along one diagonal is used. However, in the case of a square lid, the angles on both sides of the triangle divided into two diagonals with the two diagonals as the base are equal angles, i.e.
However, most lids are generally rectangular, so when two triangular lid plates are combined as shown in Figure 4, one of the tips of the triangular lid plates has an angle greater than 45 degrees. , the tip of the other adjoining lid plate is
Since the angle is smaller than 45 degrees, the force on the top of the small angle will be greater than the force on the top of the large angle, and over the years, the legs on the top of the small angle will tend to wear out. It has been found that if scratching occurs and further wear progresses, a step will develop between the two triangular lid plates, which can be dangerous.

(Means for solving the problem) In order to solve the problem, as a result of various studies, the present invention has been developed by dividing the rectangular lid into two diagonally.
When using a combination of two triangular lid plates, this problem can be solved by making the cutting lines at the tops of both ends of the diagonal lines bisectors of the interior angles of the rectangle, that is, 45 degree angles.

(Embodiment) The present invention will be described according to an embodiment shown in the drawings. In a rectangular lid for an underground structure as shown in FIG. It is composed of two lid plates in the shape of a right triangle of the plate 2, and is fitted and placed on the receiving frame 3, and is located at both ends of the adjacent sides of the lid plates 1 and 2 in the shape of a right triangle. The top portions, that is, the top portions 4 and 6 on the lid plate 1, and the top portions 7 and 9 on the lid plate 2.
At least the portion having the legs formed on the back side and in contact with the receiving frame 3 is configured to have an angle of 45 degrees, which is obtained by dividing a right angle, which is an internal angle of the rectangle, into two equal parts. That is, as shown in FIG. 2, at the tops 4 and 7 where the lid plates 1 and 2 come into contact, a leg part that comes into contact with the receiving frame 3 is formed on the back side of the trapezoidal part surrounded by broken lines.
Slightly inside this part, align it with the diagonal of the rectangular lid, or divide the part that forms the leg by the bisector of the apex angle at a 45 degree angle, as shown in Figure 3. However, between the legs, the rectangular lid may be divided along a line connecting points on the inside of the legs to form respective lid plates 1 and 2.

(Effect of the invention) As described above, the present invention provides a lid for a rectangular underground structure, in which at least the top portions of the lid plate formed by two right triangles on one diagonal are each supported by a receiving frame. Since they form an equal angle of 45 degrees, the load on the top due to passing vehicles, etc. is equal, eliminating the risk of differential wear of the legs at the top, and therefore reducing the step between the two lid plates. It will no longer occur. In addition, since the right-angled triangular lid plates are of the same type, they can be cast using a single mold like conventional products, which has the advantage of requiring a smaller mold. Although only a lid with a diameter of 10 mm is shown, it can also be applied when the opening of an underground structure is wide and a plurality of rectangular lid plates are installed in series.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a top view of the lid, FIG. 2 is a partially enlarged top view of the lid plate in FIG. 1, and FIG. 3 is a partial top view of another embodiment. , 4th
The figure is a partial top view showing a conventional example. 1, 2... Lid plate, 3... Receiving frame, 4-9... Top.

Claims (1)

[Scope of utility model registration request] A rectangular lid is divided into two by one diagonal of the rectangle, forming a right triangle shape. Two lid plates 1 and 2.
In the lid made of the lid, the tops 4, 6 and 7, 9 of the lid plates 1, 2, which form an acute angle, have at least legs that contact the receiving frame 3, and the right angle, which is an internal angle of the rectangle, is bisected into two halves. A lid for an underground structure, characterized in that it is configured to have an angle of .degree.