JP4015293B2 - Stabilized leg of small-diameter manhole made of PVC - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stable leg of a small-diameter manhole made of PVC.
[0002]
[Prior art]
At present, this type of manhole has been standardized by the Japan Sewerage Association standard as a small manhole made of hard vinyl chloride for sewerage.
[0003]
Such PVC small-diameter manholes are mainly embedded in places where vehicles with a gross vehicle weight of 2 tons or more pass on public roads, private roads, and sidewalks, and in places where vehicles with a gross vehicle weight of 2 tons or less pass in private or alleys. Is done.
[0004]
By the way, the applicant has proposed a number of such small-diameter manholes made of polyvinyl chloride (for example, utility model registration Nos. 2547479, 2424755, 2524756, 2554322, 2544132). This is commercialized, but this has been developed by the applicant and has been commercialized to contribute to PVC sewerage facilities. Based on the results, the scale has been substantially scaled up (for example, the inspection cylinder diameter has been increased to 300 mmφ), and is being promoted as a highly reliable product that also complies with the above standards.
[0005]
The polyvinyl chloride small-diameter manhole 50 will be outlined.
[0006]
5 and 6 (A-A cross-sectional view of FIG. 5), 51 is an injection-molded manhole body, which has an inlet 52 with a rubber ring outlet on the upstream side and an outlet with a differential port on the downstream side. 53, an inspection tube connecting port 54 with a rubber ring receiving port is integrally formed and provided upward.
[0007]
The rubber ring receiving port 52 has an upstream pipe 55 of the sewage main pipe, the outlet 53 with a differential port has a downstream pipe 56 of the sewage main pipe, and the inspection pipe connecting port 54 with a rubber ring receiving port has a length (buried depth). An inspection cylinder 57 of 1.2 m or more is connected to each other.
[0008]
The PVC small-diameter manhole 50 shown in the figure is called a straight type, and the inverter 58 formed inside the manhole body 51 has a straight axis and a shape. Therefore, the central portion of the inverter 58 is located directly below the inspection cylinder 57.
[0009]
Further, a stable leg 59 is integrally injection-molded and protruded on the outer side of the bottom portion of the invert part 58 of the manhole body 51. The stable leg 59 is usually a ring-shaped or comb-shaped ring. . Of course, when the small-bore manhole 50 made of PVC is a drop type, no stabilizing leg is provided.
[0010]
And this stabilization leg 59 is not prescribed | regulated in particular in the said Japan Sewerage Association standard, The shape is free, Of course, it is not prescribed | regulated also about the dimension.
[0011]
In the case of such a small leg made of polyvinyl chloride, the stabilizing leg 59 forms a predetermined gradient in the inverted portion itself, so that the inverted portion is not only reinforced, but also the stability of the main body and the horizontal In the case of the small-diameter manhole 50 made of polyvinyl chloride, the stable leg 59 performs only the stable function of the manhole body 51 in order to perform the following installation work. I got the knowledge that
[0012]
That is, the installation method of the small-diameter manhole 50 made of polyvinyl chloride will be described. In FIG. 5 and FIG. 6, a sand foundation (also referred to as earth and sand in this specification) 61 is fixed to the excavation groove 60, and the manhole main body is constructed. Where 51 is located, a joint digging 62 is made for rubber ring bonding.
[0013]
Therefore, the installation of the manhole body 51 is temporarily fixed by checking the gradient and height of the inverter 58 in accordance with the gradient of the sewage main pipes (55) and (56). Next, after checking the slope, axial center and height of the sewage main pipes (55) and (56), the rubber ring joint (52) of the sewage main pipes (55) and (56) and the inverter part 58, (53) is performed.
[0014]
The sewage main pipes (55) and (56) thus constructed are rechecked for the gradient, axial center, and height, and the design height, gradient, axial center, etc. of the inverter 58 are also rechecked and temporarily fixed. .
[0015]
Next, sand is poured alternately with a good balance between left and right so that the bottom outer side 63 of the inverted portion 58 does not become a cavity, and the sand is sufficiently hardened with a wooden saw or the like. Therefore, since the supporting surface of the bottom part of the manhole body 51 is enlarged and the side surface is sufficiently solidified, the road load resistance is increased.
[0016]
By the way, the stabilizing leg 59 of the small-diameter manhole 50 has a predetermined slope formed in the inverted portion 58, but as described above, the inverted leg is provided by the sewage main pipes (55) and (56). Since the slope of the portion 58 is further corrected, it has been found that the function of forming the portion 58 is not necessarily horizontal, and therefore the height of the stabilizing leg 59 may not be uniform.
[0017]
On the other hand, conventionally, some proposals have been made on a stable leg made of polyvinyl chloride (or polypropylene) small caliber, and when analyzed, these are roughly classified as follows.
[0018]
That is, the stabilizer legs are flat (for example, those shown in FIG. 1 of Japanese Utility Model Laid-Open No. 51-69462, Japanese Utility Model Laid-Open No. 54-141766, Japanese Patent Application Laid-Open No. 8-27883, Japanese Patent Application Laid-Open No. 9-242172). Japanese Laid-Open Patent Publication No. 9-242173, etc., and those having stable legs in a comb-like ring shape (for example, Japanese Utility Model Publication No. 54-141664, Japanese Patent Publication No. 58-5340, Japanese Utility Model Publication No. 61-45268). And the like, and the reinforcement legs are reinforced with a ring shape (for example, see Japanese Utility Model Publication Nos. 51-29654 and 54-141766).
[0019]
[Problems to be solved by the invention]
However, when the conventional leg of the small-bore PVC made of polyvinyl chloride is applied to the stable leg of the small-bore manhole made of PVC that does not require the function of forming the horizontal, and the scale and the height are substantially scaled up. The following problems were found.
[0020]
(1) In the case where the stabilizer legs in the small caliber made of PVC are flat, when the manhole body has a slope specific to the construction site, the crushed sand foundation tends to resist, However, there is a risk that the slope of the manhole body will be impaired, and as a result, the road load resistance may be reduced.
[0021]
(2) PVC (or PP) small caliber with a stable leg in the shape of a ring or a comb-shaped ring, the diameter of the stable leg is enlarged and the inspection tube is large and long. When applied to small-diameter manholes, the strength of the inverter part due to the ring-shaped stabilizing legs decreases, and heavy objects such as the nozzle tip of the jet cleaning hose inserted from the inspection cylinder during inspection cleaning are stable. If it falls unexpectedly to the center of the leg, the surface of the inverter may be cracked.
[0022]
In particular, PVC small-diameter manholes are superior in workability to concrete manholes, but the risk of breakage increases during frequent cleaning over a long period of time.
[0023]
Accordingly, the main object of the present invention is to solve such problems and to provide a stable leg with good moldability and low cost.
[0024]
[Means for Solving the Problems]
In order to achieve such an object, the gist of the present invention is as follows. 1) Stabilizing legs that can be pushed into the earth and sand are integrally formed on the outside of the bottom portion of the invert portion of the small-bore PVC manhole at the time of injection molding. A reinforcing rib is integrally formed at the time of injection molding at the position that is connected to the stabilizing leg, along the axis of the inverter part, and directly under the inspection tube. Thus, in addition to the stability that is the function of the stabilizing leg, the polyvinyl chloride small-diameter manhole stabilizing leg is characterized in that the strength of the inverted portion is improved. In addition to the reinforcing rib in Item 1, a stable leg of a small-diameter manhole made of polyvinyl chloride, which is formed by integrally molding a mesh rib having a height lower than the reinforcing rib on the side of the sprue at the time of injection molding. It is in.
[0025]
Therefore, the present invention includes the following embodiments.
[0026]
(1) Stabilizing legs and reinforcing ribs are made the same height so as not to place a burden on the cavity or mold opening of the injection mold.
[0027]
(2) The inspection cylinder and the stabilizing leg are made substantially concentrically different in diameter, the projection of the inspection cylinder protrudes from the ring-shaped stabilizing leg, and a reinforcing rib is provided on the diameter (the lowest part of the inverter part), Even if the inspection tube is expanded (450mmφ), it has shock resistance.
[0028]
(3) The thickness of the inverted part is made slightly thicker than the conventional standard to give impact resistance.
[0029]
(4) A reinforcing rib is reinforced by providing a second reinforcing rib substantially orthogonal to the reinforcing rib in the longitudinal center.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail by way of embodiments shown in the accompanying drawings.
1 is a bottom view of the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1, FIG. 3 is a bottom view of the second embodiment, and is an equivalent view of FIG. FIG. 4 is a bottom view of the third embodiment, corresponding to FIG. 1. The same parts as those in FIGS. 5 and 6 are not shown and described, but the reference numerals are the same as those in FIG. Used.
[0031]
In FIG. 1, this PVC small-diameter manhole 1 is an injection-molded product. The sewage main pipes (55) and (56) have a bore diameter of 150 mmφ, 200 mmφ or 250 mmφ, an inspection tube axial length of 1200 mm or more, a bore diameter of 300 mmφ, Convenient for a thickness of about 5 mm to 9 mm.
[0032]
1 is a straight type, and the axis 4 of the invert portion 3 of the manhole body 2 is straight and the shape thereof is formed in a substantially semi-cylindrical shape. A stable leg 5 having a diameter of about 200 mmφ, a height of about 100 mmφ, and a thickness of about 7 mm is integrally projected on the outside of the bottom of the portion 3 during injection molding.
[0033]
A long rib (having a long height) reinforcing rib 6 is provided so as to protrude integrally with the inside of the stabilizing leg 5 along the axis 4 of the inverter portion 3 at the time of injection molding. The height of the dimension reinforcing rib 6, that is, the tip is flush with the tip of the stable leg 5, so that the stability of the function of the stable leg 5 is complemented.
[0034]
The shape of the long reinforcing rib 6 has a draft of a base wall thickness of 7 mm and a tip wall thickness of 5 mm because the injection molding spur trace 7 of the manhole body 2 is located inside the stabilizing leg 5. Along with the stabilizing legs 5, it can be easily pushed into the sand foundation 61 so that the gradient of the manhole body 2 can be formed easily and accurately.
[0035]
In addition to the long reinforcing rib 6, a grid-like short dimension (having a short height) reinforcing rib parallel to and perpendicular to the long reinforcing rib 6 (approximately 10 mm square, also referred to as a mesh rib). ) 8 is integrally protruded at the time of injection molding, and the rigidity is increased by substantially increasing the wall thickness in the stable leg 5 to counteract external force, so that it can withstand impact loads and the like. .
[0036]
In particular, when the mesh rib shape is used, it is convenient for the curved surface of the inverted portion 3 (not only undercut but also rapid molding cycle).
[0037]
Therefore, the strength against impact load or the like caused by dropping of a heavy object of, for example, 3 kgf from the inspection cylinder 51 (for example, a high-pressure washing nozzle that is unexpectedly dropped) is increased, and the material resin can be saved and the moldability is not hindered. ing.
[0038]
Next, the stable leg 9 of the second embodiment will be described.
In FIG. 3, this is a bending type of 15 °, 30 °, 45 °, 60 °, 75 °, 90 ° (however, only 60 ° is shown), and the bending axis 10 of the inverter part 3 is shown. Therefore, the long reinforcing ribs 11 similar to those described above project along the bending axis 10 in the same manner as described above.
[0039]
Further, a part of the lattice of the short reinforcing ribs 12 has a flow rhombus shape parallel to and intersecting with the bending axis 10 as shown in the figure.
[0040]
Next, the stable leg 13 of the third embodiment will be described.
In FIG. 4, this is a confluence type of 45 °, 60 °, and 90 °, and the axis of the invert part 3 has a branch axis 15 that branches in a direction corresponding to these numerical values in addition to the main flow axis 14. Accordingly, the long reinforcing ribs 16 similar to those described above project along the main flow axis 14 and the branch axis 15 in the same manner as described above.
[0041]
Further, since the lattice of the short reinforcing ribs 17 is along the main flow axis 14 and the branch axis 15, it is formed in a rhombus shape.
[0042]
These ring-shaped stabilizing legs 5, 9, and 13 may have a concentric diameter or a small concentric diameter with the inspection cylinder 51, or the center positions of the stabilizing leg and the inspection cylinder may be shifted. In any case, the long reinforcing ribs 6, 11, 16 are positioned at least along the axis line (the lowest part of the inverter part) 4, 10, 14, 15 of the inverter part immediately below the inspection cylinder. (In some cases, it is positioned so as to protrude from the ring-shaped stabilizing leg), the height of the long reinforcing rib is not only low, but the maximum impact load can be supported.
[0043]
Although the present embodiment has been described with a small-bore manhole made of PVC, the present invention is not limited to this, and the PVC is embedded in the vicinity of the boundary with public roads and private areas, and a high-pressure washing jet nozzle or the like is inserted. It can be applied to small caliber public masers. Therefore, in the present specification, this public space is sometimes referred to as a small-diameter manhole made of PVC.
[0044]
【The invention's effect】
According to the present invention,
(1) Reinforcing ribs connected to the stable legs expanded as manholes are projected, so that the thickness of the invert part is not particularly increased (if the amount is increased, sufficient pressure at the time of injection molding) Insufficient cooling, unbalanced cooling, and internal cavities, which may cause a decrease in strength, which may hinder formability), increase rigidity, and improve impact resistance. In particular, it is possible to provide impact resistance to the invert part, and to provide a highly reliable small-diameter manhole made of PVC for many years.
[0045]
In particular, the drop impact is increased only for the small-diameter manhole whose inspection tube is long and has a large diameter, but it can withstand this well.
[0046]
(2) Since the stabilizing legs and the reinforcing ribs are molded at the time of injection molding, not only the rigidity is obtained, but also the moldability is maintained as before and the productivity is improved. be able to.
[0047]
(3) Both the stabilizer legs and the reinforcing ribs are pushed into or touching the earth and sand so that the rubber ring joint with the sewage main pipe and the rubber ring joint with the inspection cylinder can be fully demonstrated. -The slope of the water can be easily adapted to the slope of the main sewage mains, and the flow of the drainage can be made smooth without solids staying.
[0048]
(4) Since the reinforcing rib is provided along the axis of the inverter portion, that is, provided at the lowest bent portion, the height of the reinforcing rib can be shortened and the maximum value of the drop load can be supported.
[0049]
{Circle around (5)} Since the short mesh ribs are provided, it is surprisingly possible to prevent whitening in the vicinity of the sprue trace and improve the commercial value.
[Brief description of the drawings]
FIG. 1 is a bottom view of a first embodiment of the present invention.
2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a bottom view of the second embodiment, corresponding to FIG.
FIG. 4 is a bottom view of the third embodiment, corresponding to FIG.
FIG. 5 is a conventional example.
6 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Small bore manhole made of polyvinyl chloride, 2 ... Manhole body, 3 ... Invert part, 4 ... Axis, 5 ... Stabilizing leg, 6 ... Long reinforcing rib, 8 ... Short reinforcing rib

Claims (2)

A stable leg that can be thrust into the earth and sand is formed on the outside of the bottom part of the invert part of the small-diameter manhole made of PVC, and is integrally formed at the time of injection molding. Along with the axis of the inverter part, and at a position directly below the inspection cylinder, the reinforcing ribs are integrally molded at the time of injection molding to project and complement the stability as the function of the stabilizing leg, A polyvinyl chloride small-diameter manhole stabilizing leg characterized in that the strength of the inverted portion is improved. In addition to the reinforcing ribs in claim 1, the stability of the small-diameter manhole made of PVC in which a mesh rib having a height lower than that of the reinforcing ribs is integrally formed and protruded on the side of the sprue at the time of injection molding. leg.

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