JPH1060933A - Manhole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manhole which secures a designated effective opening while keeping a strong structure where cast iron or the like is used, and which can be easily opened and closed by only one without using another jig or the like. SOLUTION: A manhole 27 comprises a frame 1 where an opening part 7 is formed on the base plate part 3, an annular outer cover 13 freely removably opening part 7 from the upper surface side of the horizontally arranged base plate part 3, and an inner cover 19 freely removably fitted to the inside opening part 17 of the outer cover 13 from the upper surface side of the outer cover 13. In the manhole 27, it is desirable that the outer cover 13 and the inner cover 19 are both formed circular, and the inside opening part 17 is formed concentrically with the outer cover 13. Further, it is desirable that the inner cover 19 is freely removably connected to the outer cover 13 through a string type connecting means in the manhole 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manhole used for a water storage tank or a drainage basin in a sanitary facility, or a pit for an electric wire or a communication line in an electric facility, and more particularly to a manhole for facilitating opening and closing operations. It is.

[0002]

2. Description of the Related Art Generally, manholes used for sanitary facilities, electric facilities, and the like are composed of a receiving frame buried and fixed at the periphery of an opening on an installation surface, and a lid removably fitted in the receiving frame. . Both the receiving frame and the cover are made of cast iron tow, and can secure sufficient strength against a load from above.

The receiving frame has, for example, an annular shape with an inverted T-shaped cross section, and a lid is fitted on the inner peripheral surface side of the rising plate portion. The fitting part plane shape of the receiving frame and the lid is
There is a square or round shape, but a round shape is used especially when falling is reliably prevented.

[0004] Manholes provided in facility facilities are used relatively frequently to descend into the pits, such as during periodic inspections. When drainage in the pit is removed or equipment in the pit is replaced, submersible pumps, equipment and the like are taken in and out using the opening of the manhole. Therefore, in consideration of replacement of these equipments and the like, the effective size of the manhole opening is generally set to about 900 mm in diameter in the past.

[0005]

The manhole cover is
In order to secure the strength against the load from the upper part, it is made of a tough material such as cast iron. In addition, manhole,
900 diameter for replacement of equipment in the pit
In general, an effective aperture of about mm was secured. However, in manholes in facility facilities, there are cases where it is necessary to open and close the lid alone by periodic inspection or emergency inspection, and conventionally, it is difficult to open and close with a standard cast iron lid of 150 kg or more. There was a problem. In particular, when it is necessary to perform an emergency inspection of the pit equipment by one person for some reason, there is a possibility that the entry into the pit is delayed and the equipment may be hindered. Also,
Although there are jigs for opening and closing the lid, there is a problem that if it is always prepared, the cost is high and a use space is required, so that it cannot be used in a manhole provided in a narrow place. It is also conceivable to install a hanging hook above the manhole and open and close the lid with a chain block or the like, but this has also led to an increase in equipment costs. The present invention has been made in view of the above circumstances, and secures a predetermined effective opening while maintaining a rugged structure using cast iron or the like, and can be easily performed by one person without using other jigs and the like. The purpose is to provide a manhole that can be opened and closed.

[0006]

To achieve the above object, a manhole according to the present invention comprises a frame having an opening formed in a substrate portion, a frame body having an opening formed in the substrate portion, and the opening portion being formed from an upper surface side of the substrate portion arranged horizontally. And an inner lid detachably fitted to the inner opening of the outer lid from the upper surface side of the outer lid. In the manhole, it is preferable that both the outer lid and the inner lid are formed in a circular shape, and the inner opening is formed concentrically with the outer lid. Further, it is preferable that the manhole is configured to removably connect the inner lid to the outer lid via a string-shaped connecting means.

In the manhole constructed as described above, the manhole cover is formed by the outer cover and the inner cover, and the manhole cover can be opened and closed only by the small inner cover. When the outer lid is opened, if the outer lid is removed after the inner lid is removed, the outer lid lightened by the inner lid can be opened and closed. If the outer lid and the inner lid are both formed in a circular shape and the inner opening is formed concentrically with the outer lid, the distance between the outer periphery of the outer lid and the inner opening becomes uniform, and the square hole is formed in the outer lid. The decrease in strength is less than when formed. Furthermore, if the inner lid is connected to the outer lid via the connecting means, the inner lid does not drop from the opening of the frame when the outer lid is removed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a manhole according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view of a manhole according to the present invention, and FIG. 2 is a cross-sectional view of a state in which the manhole shown in FIG. In the frame 1 made of cast iron, the substrate 3 is formed, for example, in a square shape, and a diameter of 900
An opening 7 of about mm is formed.

At the edge of the opening 7 on the upper surface of the frame 1, a rising plate 9 is provided in an annular shape. The rising plate portion 9
Reinforcing ribs 11 extending in a diagonal direction of the substrate portion 3 are reinforced by being joined to a plurality of locations on the outer periphery. Frame 1
In the figure, an annular outer lid 13 is detachably fitted to the inside of the rising plate portion 9 from above. An annular lid receiving step 15 is provided on the inner peripheral surface of the rising plate 9 to protrude therefrom.
3 mounts the edge portion on the lid receiving step portion 15 so that the frame 1
Removably attached to.

At the center of the outer cover 13, for example, a diameter of 450 m
m of the inner opening 17 is formed.
7, an inner cover 19 made of cast iron is detachably fitted from above. The inner opening 17 is preferably formed concentrically with the outer lid 13 in terms of strength. A lid receiving portion 21 is provided on the inner periphery of the inner opening 17, and the inner lid 19 is attached to the inner opening 17 of the outer lid 13 by mounting the edge on the lid receiving portion 21. A pair of open / close grips 23 sandwiching the center are formed on the upper surfaces of the outer lid 13 and the inner lid 19, respectively.

The manhole 27 constructed as described above is mounted on the upper surface side of the pit ceiling 29 so that the frame 1 is aligned with, for example, the opening 31 formed in the pit ceiling 29, and concrete 33 is poured around the pit ceiling 29. Then, the upper end of the rising plate portion 9 and the floor surface 35 are mounted in the same plane. Frame 1
The upper surfaces of the outer lid 13 and the inner lid 19 attached to the opening 7 are arranged flush with the floor surface 35.

The manhole 27 attached in this manner is
Then, for example, when it is necessary to open and close the manhole cover alone due to a periodic inspection or the like, only the inner cover 19 is opened and closed. The inner lid 19 is made of cast iron, but has a diameter of 450 m.
m, it is lighter and can be opened and closed more easily than when a conventional lid made of the same material and having a diameter of about 900 mm is opened. In daily inspections,
The inside opening 17 having a diameter of about 450 mm is sufficient for a worker to enter and exit.

On the other hand, when replacement of equipment or the like in the pit occurs, the outer cover 13 is removed from the frame 1. In this case, when there are many people, the outer lid 13 with the inner lid 19 fitted can be removed at a time. When the outer lid 13 is removed by one person, the inner lid 19 can be removed first, and then the outer lid 13 can be removed. Also in this case, first, by removing the inner cover 19, the outer cover 13 having the same size as the conventional one becomes lighter by the weight of the already removed inner cover 19, so that the opening and closing of the outer cover 13 can be performed by one person. Can be easily performed.

As described above, according to the manhole 27 described above, the manhole cover is formed by the annular outer cover 13 and the outer cover 13.
And the inner lid 19 that fits into the inner opening 17 of the vehicle, so that only a small inner lid 19 can be opened for daily inspection and the like, and the manhole lid can be easily opened and closed by one person. . Further, if the outer lid 13 is opened, a large opening 7 similar to the conventional one can be secured. Then, even in the case of securing the same large opening 7 as in the related art, first, by removing the inner lid 19, the outer lid 13 which has been lightened by the inner lid 19 can be easily removed.

Further, by forming the outer lid 13 and the inner lid 19 in a circular shape, falling can be prevented and the inner opening 1 can be prevented.
7 is formed concentrically with the outer lid 13, a square hole is formed in the outer lid 13.
The strength of the outer lid 13 can be increased as compared with the case where the outer lid 13 is formed. Further, since the outer lid 13 has an annular shape, a rope or the like is passed through the inner opening 17 so that the outer lid 13 can be easily fixed in the upright state. Accidents due to
Safety can also be improved.

The manhole 27 according to the present invention is of such a size that the inner cover 19 falls from the opening 7 of the frame 1 by dividing the outer cover 13 and the inner cover 19.
If such a risk of dropping is assumed, for example, the outer lid 13 and the inner lid 19 are connected by a string-shaped connecting means (for example, a wire, a chain, or the like) 37 having an appropriate extra length. Thus, it is possible to reliably prevent the inner lid 19 from falling when the outer lid 13 is removed.

[0017]

As described above in detail, according to the manhole according to the present invention, since the manhole cover is formed by the outer cover and the inner cover, in a daily inspection, only the small inner cover is opened. The manhole cover can be easily opened and closed by one person. Also, when opening the outer lid, first,
By removing the inner lid, the outer lid that has been lightened by the inner lid can be easily removed. The outer lid and the inner lid are both formed in a circular shape, and the inner opening is formed concentrically with the outer lid, thereby increasing the strength of the outer lid as compared with the case where the square hole is formed in the outer lid. it can. Furthermore, if the inner lid is detachably connected to the outer lid via the connecting means, it is possible to reliably prevent the inner lid from dropping when the outer lid is removed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a manhole according to the present invention.

FIG. 2 is a cross-sectional view of a state in which the manhole shown in FIG. 1 is buried on the floor of the facility.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame body 3 Substrate part 7 Opening 13 Outer lid 17 Inner opening 19 Inner lid 27 Manhole 37 Connecting means

Claims (3)

[Claims] 1. A frame having an opening formed in a substrate, an annular outer lid removably fitted into the opening from an upper surface of the horizontally disposed substrate, and an upper cover from the upper surface of the outer lid. A manhole comprising: an inner lid detachably fitted into an inner opening of the outer lid. 2. The manhole according to claim 1, wherein both the outer lid and the inner lid are formed in a circular shape, and the inner opening is formed concentrically with the outer lid. 3. The manhole according to claim 1, wherein the inner lid is detachably connected to the outer lid via a string-shaped connecting means.