JP4077071B2 - Manhole frame - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manhole frame that is installed at the upper end of a manhole and supports a manhole cover.In particular, the manhole frame includes an outer frame that is fixed to the ground and an inner frame that supports the manhole cover. The present invention relates to a manhole frame in which the height and inclination of the manhole cover can be set in accordance with the height and inclination of the road surface by being provided so as to be able to be lifted and slightly tilted with respect to the outer frame.
[0002]
[Prior art]
The manhole frame is installed at the upper end of a concrete manhole tube to support the manhole cover. When the road surface with manholes is repaired or repaired, the height and slope of the road surface changes due to asphalt top coating. At this time, if the height and gradient of the manhole cover cannot be adjusted, the road surface on which the manhole is installed will be recessed or swollen.
[0003]
To avoid this problem, the manhole frame is divided into an outer frame and an inner frame, and the inner frame that supports the manhole cover is provided so that it can be lifted and tilted in the outer frame to change the height and gradient of the road surface. Sometimes a manhole frame has been proposed that allows the height and gradient of the manhole cover to be adjusted.
[0004]
This type of manhole frame is usually provided with a plurality of height adjustment bolts between the outer frame and the inner frame to adjust the height of the inner frame relative to the outer frame, and after adjustment, between the outer frame and the inner frame. The liner is inserted into the gap in the vertical direction, and the inner frame is fixed to the outer frame with fastening bolts provided in the vicinity of the liner insertion position so that the inner frame does not rattle or come off. The height adjusting bolt and the fastening bolt can have a structure shared by the same bolt and a structure provided separately.
[0005]
The liner is usually inserted in three or four places that equally divide the circumference of the manhole frame, and the total length in the circumferential direction is one third to one half of the circumference. From the viewpoint of workability, the smaller the liner, the better. However, when a large truck travels, a very large load is applied to the manhole cover, and this load is transmitted to the outer frame through the liner, so that a certain pressure receiving area is required.
[0006]
A plurality of liners are stacked so as to have a desired height, and when the manhole cover is provided with a gradient, the height of the liner inserted at a plurality of locations is changed. At this time, if the flat liners are simply stacked, the inclined inner frame and the liner come into contact with each other, and a necessary pressure receiving area cannot be secured, and a large local stress is generated at the contact portion of the inner frame with the liner. . Therefore, a structure in which the inclination of the liner upper surface is made variable by interposing two liners whose arcuate surfaces are stacked, and a liner upper surface is made to be a gradient of the inner frame by interposing a wedge-shaped liner according to the inclination angle. A matching structure has been proposed.
[0007]
The former structure can be freely adapted to the inclination angle and inclination direction of the inner frame, but if the inclination angle of each liner is not set accurately during installation, there is a risk that excessive stress concentration will occur due to contact with the inner frame. is there. On the other hand, the latter structure can set the inclination angle and the inclination direction only in a stepwise manner, but has a feature that a reliable surface contact between the inner frame and the liner is ensured and installation work is easy.
[0008]
In the case of the former structure, it is considered that the self-aligning action by contact between the arc surfaces works, but this self-aligning action does not work unless the tangential force caused by the offset load is larger than the frictional force. In order to work effectively, the curvature of the arc must be increased, but to increase the curvature, the height of the liner is increased (the height of the manhole frame is increased) or the length of the arc is decreased ( However, in reality, it is impossible to achieve a curvature that can be expected to be self-aligning, and it is necessary for the operator to adjust the inclination of each liner individually. is there.
[0009]
[Problems to be solved by the invention]
In the latter structure, i.e., the structure in which the inclined inner frame and the liner are in contact with each other by interposing a wedge-shaped liner, by preparing multiple types of wedge-shaped liners having different angles, or by stacking a plurality of wedge-shaped liners, The inclination angle of the inner frame can be adjusted at a fine angle interval that does not cause a problem in practice. However, the direction of the gradient of the manhole cover is defined by the direction of the liner insertion location that equally divides the circumference. For example, if the liner is inserted at a position where the circumference is divided into four equal parts, the direction of the gradient can be adjusted only at intervals of 90 degrees. This problem can be solved by setting the direction of the outer frame to match the road gradient. This is because the road is inclined in a direction where the center is high and the road side is low, and it is impossible to change the direction of the gradient.
[0010]
In reality, however, the direction of the outer frame is determined by other factors unrelated to the road gradient. This is because a metal fitting called a hand grip is attached to one part of the inner periphery of the outer frame, and the outer frame must be installed by aligning this hand grip with the straight part of the manhole tube already embedded in the ground. is there.
[0011]
As shown in FIG. 6, the manhole hole has a larger diameter in the underground portion than the ground surface portion, and an inclined tube 5 is provided so as to connect between them, and a manhole frame is installed at the upper end of the inclined tube 5. It has become. The inclined pipe 5 is provided with a straight portion 51 so that a handrail 52 and a ladder for a person entering and exiting the manhole frame are not reversely inclined.
[0012]
Therefore, the outer frame 1 must be attached so that the hand grip is in a direction that coincides with the handrail 52 provided on the straight portion. When the handrail 52 is not provided on the inclined pipe 5, an operator enters and exits the manhole hole by hooking the upper end of the ladder to the handgrip of the outer frame. It must be installed according to the direction. Therefore, the outer frame cannot be installed with the liner insertion position of the outer frame aligned with the direction of the road gradient.
[0013]
If the direction of the liner insertion position of the outer frame deviates from the inclination direction of the road, for example, in a manhole frame in which the liner insertion position is provided at a position where the circumference is divided into four equal parts, the inclination direction of the manhole cover is only 90 degrees apart. Since it cannot be changed, a maximum of 45 degrees shift occurs with respect to the inclination direction of the road, resulting in a non-uniform level difference that is easily visible between the periphery of the manhole cover and the road surface. If the liner insertion position on the circumference of the manhole frame is not restricted, the inclination direction of the manhole cover can be set freely, but the liner insertion position must be accurately determined by the site worker, and the arc described above The work burden on the field worker is very large, as in the case of determining the inclination angle of the liner by the surface.
[0014]
In addition, in the place where the fastening bolt for fastening the inner frame and the outer frame is provided, the load of the manhole cover and the fastening force of the fastening bolt act so as to make the internal stress applied to the inner frame uniform. A fastening bolt is preferably provided at the liner insertion position. Therefore, if the liner insertion position is provided at a position where the circumference is divided into, for example, eight or twelve so that the inclination direction of the manhole cover can be changed for each narrower angle, the structure of the manhole frame becomes complicated and there are many liners. There is an inconvenience that a variety of types must be prepared and the work burden on the field worker increases.
[0015]
The present invention has been made to solve the above-described problems, and does not excessively complicate the structure of the manhole frame, does not increase the number of liners, and increases the work load of field workers. It is an object of the present invention to provide a manhole frame in which the inclination direction of the manhole cover can be adjusted at a finer interval without making it.
[0016]
[Means for Solving the Problems]
The manhole frame of the present invention that has solved the above problems includes an outer frame 1 and an inner frame 2 that is fitted with a gap inside the outer frame 1, and an upper surface and an inner frame of an inner flange 4 provided at a lower portion of the outer frame 1. 2 by inserting the liner 7 into a position that equally divides the circumference between the lower surface of the two and fastening the inner frame 2 and the outer frame 1 with fastening bolts 6 provided near the insertion position of the liner, In the manhole frame in which the height and gradient of the inner frame 2 with respect to the outer frame 1 can be adjusted, the inner frame 2 has a fastening bolt insertion hole 24 at a position 21 that divides the circumference into an integer equal to or greater than three. The outer frame 1 has fastening bolt insertion holes 14 and 15 and positioning means 16 for the liner 7 at a position 11 that divides the circumference into the integer and a position 12 that divides the arc equally divided into a predetermined ratio. , 17.
[0017]
[Action]
When there is no particular problem in the direction of the manhole cover gradient, the fastening bolt 6 and the liner 7 are connected to the fastening bolt insertion hole 14 and the liner positioning means 16 provided at the position 11 equally dividing the circumference of the outer frame 1. And the inner frame 2 is fixed to the outer frame 1. With this fixed structure, when the direction of the manhole cover is divided into four equal parts, it can be changed by 90 degrees and when divided into three parts, it can be changed by 120 degrees.
[0018]
When it is desired to adjust the direction of the inclination of the manhole cover at a finer angle, the fastening bolt 6 and the liner 7 are attached to the fastening bolt insertion hole 15 and the liner positioning means 17 provided at the position 12 obtained by further dividing the equally divided arc. Insert the inner frame 2 and fix the inner frame 2 to the outer frame 1. With this fixed structure, the direction of the gradient of the manhole cover can be changed, for example, by 45 degrees when the arc divided into four is divided into two, and by 40 degrees when the arc divided into three is divided into three.
[0019]
In these examples, the maximum errors between the inclination direction of the road surface and the inclination direction of the manhole cover are 22.5 degrees and 20 degrees, respectively. The uneven step between them is almost invisible to ordinary passers-by.
[0020]
According to the present invention, the liner positioning means 17 and the fastening bolt insertion hole 15 need only be added only to the outer frame 1, and the liner 7 and the fastening bolt 6 are divided as they are to be inserted into the equally divided positions 11. What is necessary is just to insert in the position 12, the shape of a liner and the number of fastening bolts do not change, and the inner frame 2 may be completely the same as that of a conventional structure. Therefore, the manhole frame structure can be changed little, and a manhole frame that can adjust the inclination direction of the manhole cover in finer angle units without increasing the number of liners or increasing the work burden on the site worker is obtained. be able to.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
1 to 5 are views showing an embodiment of the present invention. FIG. 1 is a partial plan view of an outer frame, FIG. 2 is a partial plan view of an inner frame, FIG. 3 is a plan view of a liner, and FIG. FIG. 5 is an enlarged cross-sectional view of an inner frame and an outer frame shown by fastening portions.
[0022]
The outer frame 1 is made of a short cylindrical casting, and has an outer flange 3 extending outward and an inner flange 4 extending inward at the lower end. The outer frame 1 is installed with the lower surface of the outer flange 3 and the outer peripheral portion of the lower surface of the inner flange 4 in contact with the upper end of the inclined tube 5 shown in FIG.
[0023]
On the inner peripheral side of the inner flange 4, a fastening rod 13 is integrally formed at an equally divided position 11 that divides the circumference into four equal parts and a divided position 12 that divides the equally divided arc into two equal parts. The fastening rod is provided with flat U-shaped bolt insertion holes 14 and 15 in which the fastening bolt 6 can be inserted from the side. Further, liner positioning means formed by two pairs of protrusions 16 and 17 are provided on the upper surfaces of the inner flanges of the equally divided position 11 and the divided position 12. The liner 7 has a shape including a pair of positioning protrusions 8 at a portion corresponding to the positioning protrusions 16 and 17 on the upper surface, and a recess into which the positioning protrusions 16 and 17 are fitted on the lower surface of the position.
[0024]
The inner frame 2 is made of a short cylindrical casting, has a tapered surface 9 for fitting a manhole cover on the inner periphery of the upper end, and has an inner flange 10 slightly below the intermediate portion in the height direction. At a position 21 that divides the inner circumference of the inner flange 10 into four equal parts, a fastening rod 23 is formed to project inward, and the fastening rod 23 is fastened from the side in the same manner as the fastening rod of the outer frame. A U-shaped bolt insertion hole 24 through which a bolt can be inserted is provided. A recess 26 is provided on the inner periphery of the lower surface 25 of the inner frame to avoid interference with the positioning projection 8 on the liner upper surface.
[0025]
A hand grip 18 is provided at one location on the inner periphery of the lower end of the outer frame 1. The handgrip 18 is used for an operator entering and exiting the manhole hole to hang a limb, and when necessary, is used to hang the ladder by hooking the hook at the upper end of the work ladder to be inserted into the manhole hole. . As described above, the outer frame 1 needs to be attached in a direction in which the position where the hand grip 18 is provided substantially coincides with the straight portion 51 of the inclined pipe.
[0026]
The inner frame 2 is inserted into the outer frame 1 such that its lower surface 25 faces the upper surface of the inner flange 4 of the outer frame. Between the upper surface of the inner flange 4 of the outer frame 4 and the lower surface 25 of the inner frame, the liner 7 is inserted at either the equally divided position 11 or the divided position 12 and is provided at the equally divided position or divided position. The inner frame 2 is fixed to the outer frame 1 by inserting the fastening bolt 6 through the bolt insertion holes 14 and 15 and the bolt insertion hole 24 provided at the equal position 21 of the inner frame and fastening with the nut 31. Is done.
[0027]
As shown in FIG. 4, the upper surface 71 is inclined with respect to the lower surface 72 at a constant inclination angle α at each of the four equally divided positions 11 or the four divided positions 12 provided on the circumference. A set of four molded liners 7 is installed in accordance with the inclination direction of the manhole cover. For example, if an inclination angle α having 0.5 degree and 1 degree is prepared, the inclination angle of the manhole cover can be adjusted in increments of 0.5 degree by stacking them. The height of the manhole cover can be adjusted by stacking flat liners.
[0028]
In the first embodiment described above, the liner positioning projections 16 and 17 and the fastening bolt insertion holes 14 and 15 are divided into a position obtained by dividing the circumference of the outer frame into four equal parts and a position obtained by further dividing the circular arc divided into four equal parts. Is set to the position obtained by dividing the outer frame equally divided position 11 into three equal parts of the circumference and the divided position 12 divided into three equal parts by dividing the 120 degree arc into three equal parts. When the liner positioning projections 16 and 17 and the bolt insertion holes 14 and 15 are provided at these positions, the tilting direction of the manhole cover can be adjusted by using the positioning projections 16 and the bolt insertion holes 14 at the equally divided positions 11. The inclination can be adjusted in units of 120 degrees, and the inclination direction of the manhole cover can be adjusted in units of 40 degrees by using any one of the positioning protrusions 17 and the bolt insertion holes 15 provided at the divided positions 12 as appropriate. The bolt insertion hole 24 provided in the inner frame in this case is provided only at a position where the circumference is divided into three equal parts.
[0029]
In any case, by providing more division positions, it becomes possible to adjust the inclination direction of the manhole cover at a finer angle without complicating the manhole frame installation work. It is not necessary to precisely match the direction of the inclination angle, and a configuration in which a circular arc divided into 3 to 4 parts is divided into 2 to 4 parts is practical.
[Brief description of the drawings]
FIG. 1 is a plan view of an outer frame of the embodiment. FIG. 2 is a plan view of an inner frame of the embodiment. FIG. 3 is a plan view of a liner of the embodiment. [Fig.5] Enlarged cross-sectional view of the inner frame and outer frame shown in the fastening part [Fig.6] Cross-sectional view of the manhole tube installed in the ground [Explanation of symbols]
1 outer frame 2 inner frame 4 inner flange 6 fastening bolt 7 liner
14,15 Bolt insertion hole
16,17 protrusion
21 equally dividing position
24 Bolt insertion hole

Claims (1)

An outer frame (1) and an inner frame (2) fitted with a gap inside the outer frame (1), and the upper surface of the inner flange (4) provided on the lower part of the outer frame (1) and the inner frame (2) Insert the liner (7) at a position that equally divides the circumference between the inner surface (2) and the outer frame (1) with the fastening bolt (6) provided near the insertion position of the liner. In the manhole frame that can adjust the height and gradient of the inner frame (2) with respect to the outer frame (1) by fastening the inner frame (2), the inner frame (2) is divided into an integer equal to 3 or more in the circumference A fastening bolt insertion hole (24) is provided at a position (21) where the outer frame (1) is divided into a position (11) that divides the circumference into the integer and the arc that is divided into the integer
At a predetermined ratio of 2 or more
A manhole frame comprising a fastening bolt insertion hole (14, 15) and a positioning means (16, 17) for the liner (7) at an equally dividing position (12).

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