JPH116168A - Lid for underground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve corrosion resistance and baking resistance by forming either a male screw member or a female screw member with stainless steel and forming another one with a copper-based alloy. SOLUTION: Either a bolt 7 or a nut 8 is formed with stainless steel such as a stainless steel rod, and forming another one with a copper-based alloy such as a quick cutting brass or a high strength brass, and then means 5 of screwing-in is formed. Then, a bolt 7 is provided on a lid body 3 of the lid 1 of an underground structure, and a nut 8 is housed in a storage portion of a receiving frame 2. In addition, the bolt 7 is tightened to the nut 8, the lid body 3 is strongly tightened and fixed to the receiving frame 2, the lid body 3 is pressed to a packing 4 and attached to the receiving frame 2. By doing this, poor operation due to corrosion at the screwed portion by the bolt 7 and nut 8 or due to baking can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover for an underground structure such as a manhole cover or an iron cover for a common groove provided with a screwing means comprising a male screw member and a female screw member. The term “cover for underground structures” as used in the specification of the present application refers to a large iron cover, a manhole cover, a sewage basin cover, an electric power / Opening / closing iron lids for joints that can be opened and closed to protect underground facilities equipment and underground cables in communications, iron lids for power transmission, iron lids for power distribution, buried conduits under the road surface for water supply and gas piping, and their attached equipment and the ground. Fire hydrant cover, water control valve cover, partition valve cover, air valve cover, gas pipe cover, water meter cover, etc., which function as an opening / closing door.

[0002]

2. Description of the Related Art In a cover for an underground structure, a screwing means comprising a male screw member and a female screw member is widely used as an elevating mechanism, a tightening mechanism and the like. As the male screw member and the female screw member of these screwing means, those made of carbon steel or cast iron are generally used. Particularly, in view of cost, strength and the like, the male screw member and the female screw member are used. Both are often made of carbon steel for general structure or mechanical structure, the male screw member is made of carbon steel for general structure or mechanical structure, and the female screw member is made of cast iron.

[0003]

However, carbon steel and cast iron male screw members and female screw members are susceptible to corrosion and rust, especially when used for lids of underground structures installed outdoors. As a result, the torque required for the screwing operation of the screwing means increases with time, which causes a problem of malfunction.

On the other hand, in order to improve the corrosion resistance, both the male screw member and the female screw member may be made of stainless steel, or a combination of stainless steel and carbon steel or cast iron may be used.
However, in the case of such a combination, when a large torque acts on the screwing portion of the screwing means, a destructive stage in which the screwing portion adheres and does not slip, that is, a phenomenon called so-called seizure, is likely to occur, and a malfunction occurs. There is a problem that causes.

[0005] The present invention has been made in view of the above points, and has as its object to provide a lid for an underground structure provided with a screwing means having excellent corrosion resistance and seizure resistance.

[0006]

According to the present invention, there is provided a lid for an underground structure provided with a screwing means comprising a male screw member and a female screw member, wherein one of the male screw member and the female screw member is made of stainless steel. It is characterized in that it is formed of steel and the other is formed of a copper-based alloy. With this configuration, in the installation environment of the lid for the underground structure, corrosion resistance and seizure resistance are improved, and malfunction due to corrosion and seizure of the threaded portion of the male screw member and the female screw member is prevented. You.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the screwing means constitutes a lifting mechanism or a tightening mechanism. In this case, even if a large torque acts on the screwing portion of the screwing means, the occurrence of seizure is prevented. Further, malfunctions due to corrosion of the threaded portion are also prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of the results of research on the material of a screwing means adapted to the installation environment of a lid for an underground structure. The bolt (male screw member) and the nut (female screw member) of the screwing means are composed of a combination of various materials such as the same kind of metal, different kinds of metal, etc., and are subjected to a repetitive lifting test, a sanding test, and a corrosion test described below. This was carried out to obtain a suitable material for the screwing means.

1. Repetitive lifting test A lifting mechanism is composed of a jack bolt (male screw member) and a nut (female screw member) as a screwing means, and jacks are repeatedly raised and lowered by applying a load by variously combining jack bolt and nut materials. The fluctuation of the up torque was measured, and the seizure resistance was evaluated. The jack bolts and nuts are Tr24 × specified by JISB0216.
5 was used.

FIGS. 1 and 2 show a test apparatus subjected to a repetitive lifting test. The test apparatus 100 has a gate-shaped frame 102 suspended from a base 101 and a jack bolt 105.
Are rotatably supported at upper and lower ends by bearings 106 and 107 on a frame 102 and a base 101. The bearing 107 is a thrust bearing. The lifting table 104 is provided with a nut 108 at the base end, and is screwed to the jack bolt 105. The upper end 105a of the jack bolt 105 is connected to a driving rotary shaft 109 of a drilling machine as a driving device. In the drilling machine, the jack bolt 105 is repeatedly rotated forward and backward by a predetermined number of rotations to move the lifting table 104 up and down. On the lift 104, the weight W with the predetermined load is placed.

In this test, it is assumed that the lid body (weight: 225 kgf · cm) of the lid for the underground structure is jacked up, and the moment is considered so that the calculated jackup torque becomes 200 kgf · cm. The weight of the weight W was 36 kg. With this load applied, the elevator 1
04 was continuously moved up and down (up to 200 times), and the fluctuation of jack-up torque was measured. The measurement of the jack-up torque was performed using a torque wrench.

The lifting speed of the lifting table 104 is about 1
0 s / round trip. In the test apparatus 100 subjected to the above-described repeated lifting test, the jack bolt 105 and the nut 1
The combination of materials 08 (material of jack bolt 105 + material of nut 108) was as follows. (1) SUS304 + Free-cutting brass (Invention material 1) (2) SUS304 + High-strength brass (Invention material 2) (3) SS400 + S45C (Comparative material 1) (4) SUS304 + S45C (Comparative material 2) C3560 specified in JIS H3100 (copper and copper alloy plates and strips), and high-strength brass
C6782 specified in ISH3250 (copper and copper alloy bars)
It was used.

SUS304 is JISG4303.
(Stainless steel rod), SS400 is JISG310
1 (rolled steel for general structure), S45C is JISG40
51 (carbon steel for machine structural use) was used. The results of the repeated lifting test are shown in Table 1 and FIG. As is clear from Table 1 and FIG. 5, the invention material 1 (SUS3
04+ free-cutting brass) and invented material 2 (SUS304 + high-strength brass), seizure occurs despite the severer test conditions (especially the vertical speed) compared to the actual environment. Completed up and down 200 times without
Since the rise of the jack-up torque is small, the seizure resistance can be sufficiently evaluated.

On the other hand, Comparative material 1 (SUS400 +
In the combination of S45C), seizure occurred 26 times, and the jack-up torque was 900 kgf · cm or more. Further, in the case of the combination of the comparative material 2 (SUS304 + S45C), seizure occurs when the number of times of ascending and descending is one, which is far from a practical level, and this combination cannot be used.

[0015]

[Table 1]

2. Sanding Test In order to more closely match the test conditions of the above-described repetitive lifting test to the actual environment, while constantly sanding the screw portion of the jack bolt 105 and the nut 108 of the test apparatus 100 shown in FIGS. Repeated lifting tests were performed. In the test apparatus 100 used for the sanding test, the combination of the materials of the jack bolt 105 and the nut 108 (the material of the jack bolt 105 + the material of the nut 108) was as follows. (1) SUS304 + Free-cutting brass (Invention material 3) (2) SS400 + S45C (Comparative material 3) Here, the same free-cutting brass, SUS304, SS400, and S45C as those used in the previous repetitive lifting test were used. used.

The results of the sanding test are shown in Table 2 and FIG.
As is clear from Table 2 and FIG. 6, the invention material 3 (SUS
In the combination of 304 + free-cutting brass), seizure did not occur even in an environment where sand was bitten, and ascending and descending 200 times were completed, and the seizure resistance was good. On the other hand, in the combination of the comparative material 3 (SS400 + S45C),
Seizure occurred at five times of elevating.

[0018]

[Table 2]

3. Corrosion test As a screwing means, a lifting mechanism is constituted by a jack bolt (male screw member) and a nut (female screw member) as in the above-mentioned repetitive lifting test and sanding test. Below, the temporal change of the jack-up torque was measured, and the corrosion resistance was evaluated. The salt spray test
The test was performed according to the test method specified in JISZ2371.

FIGS. 3 and 4 show a test apparatus (elevating mechanism) used for the salt spray test. This test apparatus 110
It has the same configuration as the test apparatus 100 shown in FIGS. 1 and 2, and the same members are denoted by the same reference numerals and description thereof will be omitted. In this test apparatus 110, the combination of the materials of the jack-up bolt 105 and the nut 108 (the material of the jack bolt 105 + the material of the nut 108)
It was as follows. (1) SUS304 + free-cutting brass (Invention material 4) (2) SUS304 + high-strength brass (Invention material 5) (3) SUS304 + brass (Invention material 6) (4) SS400 + S45C (Comparative material 4) Brass is C specified in JIS H3100.
Using 2600, free cutting brass, high strength brass, SUS30
4, SS400 and S45C used were the same as those used in the above-mentioned repetitive lifting test and sanding test.

Then, the four types of the test devices 110 were subjected to a salt spray test for each of the three test devices 110, the thrust coefficient was measured at each elapsed time, and the change over time of the jack-up torque was determined from the thrust coefficient. Regarding the measurement of the thrust coefficient, the measurement point (rod 111)
Was applied to the jack bolt 105 with a torque wrench 112 in the range of 200 to 600 kgf · cm in steps of 100 kgf · cm, and the upward thrust generated at that time was measured by an autograph. Then, the slope was determined from the value of each thrust for each applied torque. The value of this inclination is the thrust coefficient. Then, by dividing the weight of the object to be jacked up by the thrust coefficient, a jack-up torque required to jack up the object is obtained.

In this test, the jack-up torque was calculated by assuming the lid body of the lid for the underground structure as the object to be placed and setting its weight to 225 kg. The results of the corrosion test are shown in Table 3 and FIG. As is clear from Table 3 and FIG.
Invention material 4 (SUS304 + free-cutting brass), invention material 5 (SU
S304 + High-strength brass) and Invention Material 6 (SUS304)
+ Brass), the jack-up torque slightly increased with the lapse of time, but the comparative material 4 (SS40
The inclination is smaller than that of the combination of (0 + S45C).

That is, it can be said that the inventive material is superior in corrosion resistance as compared with the comparative material, and that the jack-up torque due to corrosion does not increase with time.

[0024]

[Table 3]

As described above, it is clear from the results of each test that both the seizure resistance and the corrosion resistance are improved by using a combination of stainless steel and a copper alloy as the material of the bolt and nut. The stainless steel may be martensite or ferrite, in addition to the austenitic stainless steel such as SUS304. Further, as the copper-based alloy, free-cutting brass of C3560 specified in JIS 3100 and C67 specified in JIS 3250 are used.
82 high strength brass, C2600 brass specified in JIS 3100, C3561 and C3 specified in JIS 3100
Free-cutting brass such as 710, C3710, C3713, JIS
High strength brass of C6783 specified by H3250, JISH31
Brass such as C2680, C2720 and C2801 specified in 00, tinned brass of C4250 specified in JIS 3100, admiralty brass specified in C4430 specified in JIS 3100, C4621 and C464 specified in JIS 3100
Nepal brass such as 0, C614 defined by JIS H3100
Aluminum bronze such as 0, C6161, C6280, and C6301 may be used.

Next, one of the above-mentioned screwing means of the present invention, that is, one of a bolt (male screw member) and a nut (female screw member) is formed of stainless steel, and the other is formed of a copper alloy. The underground structure lid to which the screwing means is applied will be described. FIG. 8 shows a sectional view of a first embodiment of a lid for an underground structure using the screwing means according to the present invention as a fastening mechanism.

In FIG. 8, the lid 1 for an underground structure is, for example, a completely waterproof iron cover, and has a circular shape in plan view composed of a receiving frame 2 and a lid body 3, and its upper surface is flush with the ground surface. It has been installed. The receiving frame 2 forms a fitting surface 2b with a lid body 3 having a tapered upper circumferential surface of the support portion 2a, and the lid body 3 is fitted by reducing the outer peripheral surface of the rim winding 3a into a tapered shape. The surface 3 b is fitted to the fitting surface 2 b of the receiving frame 2. An annular groove 2c is provided in the lower part of the fitting surface 2b of the receiving frame 2 along the circumferential direction. A packing 4 is mounted in the annular groove 2c, and the annular groove 2c is pressed against the lower end of the lid body 3 in a liquid-tight manner. ing. That is, the lid body 3 is fitted and supported by the tapered fitting surface 3b without rattling on the tapered fitting surface 2b of the receiving frame 2, and is further completely supported by the packing 4 in a liquid-tight manner. The cover main body 3 is provided with a plurality of, for example, three screwing means 5 arranged at equal intervals along the circumferential direction of the receiving frame 2.
To the receiving frame 2.

The screwing means 5 is, as shown in FIG.
, And a nut 8 housed in the housing 2d of the receiving frame 2. The nut 8 has a quadrangular shape in a plan view and is accommodated in a square hole 9a of the holder 9 so as not to rotate and not to deviate. The holder 9 has a holding plate 10 welded to the opening end on the lower surface. When the bolt 7 is loosened, the holding plate 9 is lowered and the bolt insertion hole 10 a protruding from the holding plate 10 is inserted into the holding portion 2 d of the receiving frame 2. Projection 2 protruding from the bottom
e and is positioned. Bolt 7 and nut 8
One of them is formed of stainless steel (for example, SUS304), and the other is a copper-based alloy (for example, free-cutting brass)
It is formed with.

The screwing means 5 tightly fixes the cover body 3 to the receiving frame 2 by fastening the bolt 7 to the nut 8. As a result, the lid body 3 is pressed against the packing 4 to be completely waterproof and mounted. When the lid body 3 is opened, the bolt 7 is loosened to release the screw engagement with the nut 8, and a crowbar is inserted into the burl hole 3e of the lid body 3 shown in FIG. After releasing the fitting, the hardware 11 is lifted and removed from the receiving frame 2.

Since one of the bolt 7 and the nut 8 is formed of stainless steel and the other is formed of a copper-based alloy, even if a large tightening torque is applied to the screwed portion, Is prevented. Further, corrosion of the bolt 7 and the nut 8 due to rainwater or the like is also prevented. As a result, malfunction of the threaded portion between the bolt 7 and the nut 8 is prevented. FIG.
2 shows a sectional view of a second embodiment of a lid for an underground structure to which the screwing means according to the present invention is applied. In the second embodiment, the screwing means is used as a lifting mechanism. In FIG. 10, an underground structure lid 21 is an underground structure lid provided in an underground structure such as a manhole, a bit for storing facility equipment for power and communication, a common ditch for installing an underground cable, and the like. And a lid body 23, 23, which can be opened and closed, which is placed on the receiving frame 22 installed at the upper end of the frame.

The underground structure lid 21 has a rectangular shape in a plan view and includes a receiving frame 22 and two lid bodies 23.
The upper surface is set flush with the ground surface. When the lid is opened, the lid bodies 23 are lifted up to the upper surface of the receiving frame 22 so that the lid can be opened in any direction of the arrow A or the arrow B. Rails 24 are arranged on the receiving frame 22 so as to be able to move up and down along opposing inner wall surfaces forming the long sides. The upper surface of the rail 24 is a rolling surface 24a, and a reinforcing beam 24b is formed on the lower surface over the entire length along the longitudinal direction. Rail 2
A concave portion 24c is formed in the center of 4, and a hole 24d is formed in the center of the bottom surface as shown in FIG.
The hole 24d is disposed on a straight line extending in the longitudinal direction substantially at the center of the rolling surface 24a.

The screwing means 25 is provided between the receiving frame 22 and the recess 24c of the rail 24. This screwing means 25
Is the hole 2 in the recess 24c of the rail 24 as shown in FIG.
4d, a nut 26 is fitted and fixed, and a jack bolt 27 supported on the receiving frame 22 side. The nut 26 has an upper part fitted in the hole 24d and a lower part in the concave part 2d.
4c is fixed to the lower surface by screws 28.

The jack bolt 27 is screwed to the nut 26 of the rail 24, and its upper and lower ends are mounted on bearing seats 22g and 22h formed integrally with the upper and lower ends of the inner wall surface of the receiving frame 2, respectively. It is rotatably supported via 29 and 30. The lower bearing 30
Uses a thrust bearing because a large load is applied in the axial direction when the rail 24 is raised and lowered. The upper end of the jack bolt 27 is a quadrangular prism-shaped protrusion 27a, which is housed in a hole 22i opened on the upper surface of the mounting seat 22g. The jack bolt 27 rotates the rail 24
Is raised and lowered horizontally. One of the jack bolt 27 and the nut 26 is made of stainless steel (for example, SU
S304), and the other is formed of a copper-based alloy (for example, free-cutting brass).

The lid body 23 is provided with wheels 32 at the front, rear, left and right positions on the lower surface, respectively.
It is possible to roll. These lid bodies 23, 23
In the state in which the front and rear wheels 32 are placed on the rails 24, the front and rear wheels 32 are locked to the respective wheel receivers 24 e of the rails 24.
When the lid body 23 is fitted to the receiving frame 22 and is in the closed state, the rail 24 is lowered to the lower limit position. At this time, each wheel 32 is slightly separated from each wheel receiver 24e of the rail 24, and prevents the weight of the lid body 23 from being applied to the rail 24 and the jack bolt 27 in the closed state.

When opening the lid main body 23, the operator fits the socket wrench 35 into the projection 27a on the upper end of the jack bolt 27 and rotates it. Jack bolt 27
Raises the rail 24 horizontally with the rotation. When the rail 24 rises slightly, each wheel receiver 24e becomes
2, and then pushes up the lid body 23 vertically as it rises.

When the rail 24 reaches the upper limit position as shown in FIG.
2g, the rolling surface 24a is flush with the upper end surface (ground surface) of the receiving frame 22. Next, the worker operates the lid body 2
3 and 23 are moved horizontally from the receiving frame 22 to the ground surface side, and the lid is opened. In the above configuration, one of the jack bolt 27 and the nut 26 is formed of stainless steel, and the other is formed of a copper-based alloy. Even if the weight of the rail 24 and the full load of the lid main bodies 23, 23 are applied to the joining portion, seizure of the threaded portion is prevented. Also, corrosion due to rainwater or the like is prevented. This prevents a malfunction of the screwed portion between the jack bolt 27 and the nut 26, and allows the lifting operation to be always performed well.

In the second embodiment, the description has been given of the case where the screwing means is applied to an elevating mechanism for directly elevating and lowering the rail by jack bolts. However, the present invention is not limited to this. Mechanism, for example,
The structure described in Japanese Patent No. 60685, that is, rails are provided in parallel on the opposing inner side surfaces of an inlet formed in the center of a receiving frame (outer frame), and the rail is connected to the receiving frame by two links to form a parallelogram. By pivotally connecting so as to form and raising and lowering the elevating body provided in the hole through rotation of a screw rod or the like, the rail is raised and lowered while the lid body is placed thereon. Of course, the present invention can also be applied to a mechanism for elevating and lowering a lid for an underground structure having a structure in which the lid body is horizontally moved at the time of ascent and pulled out to the ground surface to open the lid.

[0038]

According to the lid for an underground structure of the present invention, in the lid for an underground structure provided with a screwing means comprising a male screw member and a female screw member, one of the male screw member and the female screw member is provided. Is formed of stainless steel and the other is formed of a copper-based alloy, thereby preventing operation failure due to corrosion of the threaded portion of the male screw member and the female screw member, operation failure due to seizure, and the like.

In particular, in the cover for underground structures, the screwing means of the present invention is used as a fastening mechanism for fastening and fixing the lid body to the receiving frame, or as an elevating mechanism for elevating and lowering a rail provided on the receiving frame side. By applying, smooth operation is always maintained, and durability and operation stability of the lid for the underground structure are improved.

[Brief description of the drawings]

FIG. 1 is a front view of a test apparatus used for a repeated lifting test.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a front view of a test device used for a corrosion test.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a characteristic diagram showing a relationship between the number of times of lifting and lowering of the lift table and the jack-up torque by the test apparatus of FIG.

FIG. 6 is a characteristic diagram showing a relationship between the number of times of lifting and lowering of a lifting platform and a jack-up torque in a sanding test by the test apparatus of FIG.

FIG. 7 is a characteristic diagram showing a relationship between elapsed time and jack-up torque by the test device of FIG.

FIG. 8 is a sectional view of a first embodiment of the lid for underground structure according to the present invention.

FIG. 9 is an enlarged view of the screwing means (tightening mechanism) of FIG. 8;

FIG. 10 is a sectional view of a second embodiment of the lid for underground structure according to the present invention.

FIG. 11 is an enlarged view of the screwing means (elevating mechanism) of FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 21 Underground structure lid 2, 22 Receiving frame 3, 23 Lid body 5 Screwing means (tightening mechanism) 7, 27 Bolt (male screw member) 8, 26 Nut (female screw member) 24 Rail 25 Screwing means (Elevating mechanism) 29, 30 Bearing 100 Test apparatus (Repeated elevating test) 110 Testing apparatus (Corrosion test) 101 Base 102 Frame 105 Bolt (male screw member) 108 Nut (Female screw member) 104 Elevating table 109 Drive rotating shaft 111 Rod (Measurement point) 112 Torque wrench

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Makoto Oyama 5-8-18 Kakame, Hakata-ku, Fukuoka City, Fukuoka Prefecture Inside Hinoide Waterworks Equipment Co., Ltd.

Claims (2)

[Claims] 1. An underground structure lid provided with a screwing means comprising a male screw member and a female screw member, wherein one of the male screw member and the female screw member is formed of stainless steel, and the other is formed of stainless steel. Formed of a copper-based alloy. 2. The underground structure lid according to claim 1, wherein said screwing means constitutes a tightening mechanism or a lifting mechanism.