JP2001235075A - Expansion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion joint that is storable, in a compact posture, in a hand hole without an increase in the manufacturing cost. SOLUTION: The expansion joint 10 is for use in the connection between power cable protecting tubes 2. The expansion joint 10 comprises a socket portion 10f radially expanded into a size to accommodate an inserted end edge of the power cable protecting tube 2 and provided with a rubber ring receiving portion 10e having the practically same diameter inward of the related end edge of the expansion joint 10 to hold an annular seal member 11 of a rubber system material slid therein, and a fixing socket portion 17 provided at the end edge opposite to the socket portion 10f to maintain a watertight fit with the connected power cable protecting tube 2 by means of an watertight rubber member 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion joint suitable for connecting a power cable protective tube to a handhole.

[0002]

2. Description of the Related Art Conventionally, an expansion joint 1 used for connection between power cable protective tubes 2 and 2 and housed in a handhole.
8 to 10 are known.

[0003] In such a structure, the expansion joint 1 is provided with a receiving portion 1d of a large-diameter portion 1a to which a power cable protective tube 2 is connected.
And an opposite-side connecting portion 1c located on the opposite side, with an intermediate portion 1b interposed therebetween. Among them, a rubber waterproof seal 3 is mounted on the inner surface side of the groove 4 formed in the receiving portion 1d of the large diameter portion 1a. And this waterproof seal 3 is comprised so that it may interpose between the end part 2a of the power cable protective tube 2 inserted from the large diameter part 1a side, and this expansion joint 1, and performs sealing.

[0004] The waterproof seal 3 has dimensions and hardness as shown in Table 1 below.

[0005]

[Table 1]

The waterproof seal 3 is formed with a seal body 3a having an end abutting on the outer periphery of the power cable protective tube 2 toward the inside in the entire circumference, and can be shared with a sewage and water supply waterproof seal. It is configured as follows.

The opposite connection portion 1c located at the opposite end edge of the receiving portion 1c has a substantially tapered opening shape so as to maintain watertightness when connected to the power cable protection tube 2. A fixed receiving portion 6 is formed.

Next, the operation of the conventional expansion joint will be described.

[0009] In the prior art thus constructed, as shown in FIG. 10, the power cable protective tubes 2 are placed in a concrete handhole 5 projecting above the surface of the ground at a predetermined interval. A plurality of expansion joints 1 are bundled and fixed at the portion.

At this time, the core 2 of the power cable protective tube 2, 2
While the distance L1 between b and 2b is approximately 175 mm, the maximum outer diameter L2 is approximately 185 mm in the large-diameter portion 1a because the groove 4 is formed. Therefore, as shown in FIG. Are offset from adjacent expansion joints 1 and 1 and arranged in a staggered manner.

For this reason, the waterproof seal 3 is shared with the waterproof seal for sewage and water supply, so that even if the grooves 4 and 4 are bulged, they are efficiently stored in the handhole 5 without interference. Can be done.

[0012]

However, such a conventional expansion joint has the following problems.

That is, as shown in FIG.
It is necessary to adjust the length of the power cable protective tube 2 in accordance with the distance from the adjacent handhole 5 by arranging the expansion joints 1 in a staggered manner using various types of expansion joints 1. Was not good.

In addition, since the expansion joints 1 are arranged in a staggered manner, there are cases where long and short expansion joints are used in various types. However, in this respect, it has been difficult to suppress an increase in manufacturing cost.

An object of the present invention is to solve the above-mentioned problems and to provide an expansion joint that can be compactly stored in a handhole without increasing manufacturing costs.

[0016]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, there is provided an expansion joint used for a connecting portion of a power cable protection pipe, wherein the expansion joint includes the power cable protection pipe. The end of the pipe is expanded to a size that can be inserted, and has a substantially same diameter in the pipe inward direction from the end of the expansion joint main body, and is made of a rubber-based material so that the power cable protection pipe can slide. A configured annular seal member, a receiving portion provided with a rubber ring receiving portion to be mounted,
A watertight rubber is provided on the opposite edge of the receiving portion,
It is characterized by an expansion joint having a fixed receptacle for maintaining watertightness between the power cable protective tube to be connected.

More specifically, for example, the maximum outer diameter of the expansion joint is defined as the outer diameter of the opening of the socket × (1 + x), (0 ≦ x <0.0
As 2), the bulge due to the groove can be eliminated.

According to the first aspect of the present invention, when the annular sealing member is inserted into the pipe from the edge of the receiving portion, the sliding member slides in the rubber ring receiving portion along the annular sealing member. Inserted, the annular seal member is located between the expansion joint and the power cable protective tube,
Seal between both members.

Since there is no need to form a groove in the expansion joint as in the prior art, a swelling portion can be eliminated. For this reason, even if the expansion joints are constructed and bundled with one kind, there is no interference part, so that they can be densely packed and compactly stored in the handhole.

In addition, the positions in the length direction of the expansion joints are aligned, and the adjustment of the length of the power cable protection tube is unnecessary or simplified.

Further, according to the second aspect of the present invention, an annular flange is provided at an edge of the annular seal member with an engagement flange which is engaged with an edge of the receiving portion. The one main body is provided with a plurality of pull-out preventing protrusion pieces each having a tip inclined in the power cable protective tube insertion direction and separated by a predetermined distance along the axial direction, and at least one of the pull-out preventing protrusion pieces has: 2. The expansion joint according to claim 1, wherein a fall-prevention step portion for suppressing the protrusion of the sealing piece main body in a pulling-out direction by pulling out the power cable protection tube is integrally formed.

According to the second aspect of the present invention, the insertion flange is provided at the edge of the annular seal member so as to be engaged with the edge of the receiving portion, so that a desired insertion can be achieved. Stop the annular seal member by an amount.

The annularly formed projection seal piece main body is provided with a plurality of pull-out prevention projection pieces separated by a predetermined distance in the axial direction. Since the pull-out preventing projection has a tip inclined in the power cable protection tube insertion direction, the power cable protection tube can be easily inserted, and a good sealing property is obtained by dispersing a plurality of sealing portions. Can be

In addition, of the pull-out preventing projection pieces,
At least one of the power cable protective tubes is integrally formed with a fall prevention step that suppresses the fall of the protrusion seal piece body in the pull-out direction due to the pull-out of the power cable protection tube, and the fall of the protrusion seal piece body is suppressed. Thereby, the pull-out resistance increases and the power cable protective tube is prevented from falling off from the expansion joint.

According to a third aspect of the present invention, the fixed receiving portion has a tapered opening shape having an edge opening having a diameter smaller than a maximum diameter portion of the expansion joint body. Or the expansion joint according to 2.

According to the third aspect of the present invention, the tapered opening has an edge opening having a diameter smaller than a maximum diameter portion of the power cable protection tube. When the expansion joints are bundled,
There is no risk of interference with other expansion joints arranged adjacently.

Therefore, it is possible to obtain an expansion joint which is easy to construct and can be compactly stored in the handhole.

[0028]

First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. Parts that are the same as or equivalent to those in the conventional example will be described with the same reference numerals.

FIGS. 1 to 7 show a first embodiment of the present invention.
1 shows an expansion joint of the present invention. Parts that are the same or equivalent to those in the conventional example will be described with the same reference numerals.

First, the structure will be described. In the first embodiment, there is provided an expansion joint 10 used for connecting a connecting portion between the power cable protective tubes 2 and 2 and housed in the handhole 5. . The expansion joint 10 includes a large diameter portion 10.
a, an intermediate portion 10b which is fixed with substantially the same inner diameter as the outer diameter of the power cable protection tube 2 and guides the insertion so that watertightness is maintained when the power cable protection tube 2 is connected to the power cable protection tube 2; A fixed receiving portion 6 having a substantially tapered opening shape is formed and mainly configured.

The large-diameter portion 10a is determined by setting the maximum outer diameter of the expansion joint 10 to the outer diameter of the opening of the receiving portion 10f × (1+
x), (0 ≦ x <0.02) to eliminate the bulging portion due to the groove as in the related art.

The expansion joint 10 is made of a heat-resistant and impact-resistant synthetic resin composition (mainly chlorinated vinyl chloride resin) in order to impart thermal shock resistance, and has a Vicat softening point of 83.
Above ° C, the impact resistance has passed the pickaxe impact test.

In this pickaxe impact test, as shown in FIG. 5, a pickaxe-shaped tip 21 is provided on the front surface of a 16.16 kg weight 20 provided via an arm 19 at a position 1 m from the center of rotation 18. From the height of α = 90 °, and strikes the side surface of the expansion joint 10, which is substantially fixed in the corner by the pressing piece 23 fixed to the pedestal 22.

As shown in FIGS. 6 and 7, the tip end portion 21 has a total height H = 32 mm, a length W × W = 15 mm × 15 mm of each piece on the bottom surface, and a height
mm, length of each piece of end face 21b of vertex 21a w × w =
It has a substantially quadrangular pyramid shape of 3 mm × 3 mm.

The inside of the edge 10d of the large diameter portion 10a is enlarged to a size in which the edge 2a of the power cable protective tube 2 can be inserted, and a receiving portion 10f provided with a rubber ring receiving portion 10e.
Are formed.

The rubber ring receiving portion 10e is formed to have substantially the same diameter from the edge of the expansion joint 10 toward the inside of the pipe.

An annular seal member 11 made of a rubber material is slidably inserted into the rubber receiving portion 10e.

The annular seal member 11 has, for example, dimensions and hardness as shown in Table 2 below, and as shown in FIG.
A locking flange 11a that locks to the 0f end is provided.

[0039]

[Table 2]

The annular seal member 11 has a first to fourth projection seal piece main body 1 which is annularly protruded from the inner surface.
2 to 15 are formed.

The first to fourth projection seal piece main bodies 12
15 to 15 are provided with pull-out preventing protrusions 12a to 15a each having a tip inclined in the insertion direction of the power cable protective tube and separated from each other by a predetermined distance along the axial direction.

Of these, the pull-out preventing protrusions 13a,
On the opening side of the receiving portion 10f of 14a, fall prevention step portions 13b and 14b for integrally suppressing the projection seal piece main bodies 13 and 14 in the pulling direction by pulling out the power cable protection tube 2 are integrally formed. Have been.

For this reason, the rubber compression ratio is changed from 1.6 to 1.4, and the contact area of rubber is tripled.

[0044]

## EQU00001 ## Rubber compression ratio.times.contact area = f.times.rubber compression ratio.times.contact area From the relationship of the above equation 1, the tube insertion property is 1.61.
7 (N) ｛1.980 (N) or less｝ The pipe pulling property is 3.430 (N) ｛1.980.
(N) The test value of｝ is obtained. In the water tightness test, the inner water pressure was 1.0 Mpa, and the outer water pressure was 1.0 Mpa.
Has passed.

An annular watertight rubber member 16 is provided inside the opposite end edge of the fixed receiving portion 1c so as to maintain watertightness between the power cable protective tube 2 and the power cable protective tube 2 to be connected. A fixed receiving portion 17 having a substantially tapered opening shape is formed.

The angle of inclination inside the fixed receiving portion 17 is
Δt = 6/1000, and is set to expand outward. At a distance d = 100 mm from the edge 6b to the watertight rubber member 16, the edge 6a of the fixed receiving portion 6 is The expansion joint 10 has a smaller diameter than the maximum diameter portion.

Further, the watertight rubber member 16 has a contact inclined surface portion 16a on the inner side surface thereof, which is brought into contact with the outer peripheral surface of the end edge 2a of the power cable protective tube 2 and pressed.

Next, the operation of the expansion joint according to the first embodiment will be described.

In the thus constructed expansion joint 10 of the first embodiment, when the annular seal member 11 is inserted into the pipe from the edge 10d of the socket 10f, the annular seal member 11 It is slid and inserted in the wheel receiving portion 10e, is located between the expansion joint 10 and the power cable protection pipe 2, and is sealed between both members.

Since there is no need to form a groove in the expansion joint 10 as in the prior art, a swelling portion can be eliminated. For this reason, as shown in FIG.
Even if the expansion joints 10 are configured and bundled, there is no interference part, so that the expansion joints 10 can be densely stored in the handhole 5 compactly.

In addition, the positions of the expansion joints 10 in the length direction are aligned, and the adjustment of the length of the power cable protective tubes 2 and 2 is unnecessary or simplified. Further, since the expansion joint 10 can be constituted by one type, an increase in manufacturing cost can be suppressed also in this regard.

Further, in the first embodiment, the locking flange portion 11d provided at the edge of the annular seal member 11 shown in FIG. The annular seal member 11 is stopped at the insertion amount of.

In the fixed receiving portion 17 on the opposite side of the receiving portion 10f, the end 2a of the power cable protection tube 2 is inserted along the tapered opening shape, about 100 mm from the end 17a. The inclined surface portion 16 is brought into contact with the watertight rubber member 16 so that
aPressing is performed by contacting the outer peripheral surface.

For this reason, by filling the gap between the power cable protective tube 2 and the fixed receiving portion 6a with mortar, the watertightness can be easily improved, and the workability is good.

The first to fourth projection seal piece main bodies 12 to 15 formed in an annular shape are provided with a plurality of pull-out prevention projection pieces 12 a to 15 a at predetermined intervals along the axial direction. I have. These pull-out preventing projection pieces 1
In 2a to 15a, since the tip is inclined in the insertion direction of the power cable protection tube, the power cable protection tube 2 can be easily inserted, and a good sealing property can be obtained by dispersing a plurality of sealing portions.

Moreover, the pull-out preventing protrusion pieces 12a to 12a-1
5a, the pull-out prevention protrusions 13a to 14a are integrally formed with fall prevention step portions 13b and 14b for suppressing the protrusion seal piece main bodies 13 and 14 from falling in the pull-out direction due to the pull-out of the power cable protection tube 2. Since the protrusion seal piece main bodies 13 and 14 are suppressed from falling down, the pull-out resistance is increased and the power cable protective tube 2 is prevented from falling off from the expansion joint 10. In the first embodiment, the tube insertion force of 1.617 is calculated based on the test values.
Compared with (N), the pipe pulling force 3.430 (N) is larger,
It can be seen that the tube insertability is good and the resistance to tube pullout is large. The watertightness is determined by the internal water pressure =
A value of 1.0 Mpa and an outside water pressure of 1.0 Mpa is obtained.

As described above, without impairing the assembling property and watertightness, as shown by the two-dot chain line and the one-dot chain line in FIG.
The end 2a of the power cable protection tube 2 is movable along the annular seal member 11, and the contraction of the power cable protection tube 2 in the axial extension direction is absorbed.

Therefore, it is possible to obtain the expansion joint 10 which is compact and has good space efficiency even when bundled and has good mounting workability without increasing the manufacturing cost.

Although the first embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to the first embodiment, and there are design changes and the like without departing from the gist of the present invention. Even this is included in the present invention.

For example, in the first embodiment, the fall prevention step portions 13b, 14b are pulled out of the protrusion prevention protrusions 13a,
Although it is provided on 14a, it is not particularly limited to this. For example, it may be provided on the pull-out preventing protrusions 12a and 15a, which can improve the degree of close sealing and can suppress an increase in the outer diameter of the large diameter portion 10a. , The quantity, shape and material are not particularly limited.

[0061]

As described above, according to the first aspect of the present invention, when the annular seal member is inserted into the pipe from the edge of the socket, the rubber ring is formed along the annular seal member. The annular seal member is slid and inserted in the receiving portion, and is located between the expansion joint and the power cable protection tube, and seals between the two members.

Since there is no need to form a groove in the expansion joint as in the prior art, a swelling portion can be eliminated. For this reason, even if the expansion joints are constructed and bundled with one kind, there is no interference part, so that they can be densely packed and compactly stored in the handhole.

Moreover, the positions of the expansion joints in the length direction are aligned, and the adjustment of the length of the power cable protection tube is unnecessary or simplified.

Further, according to the second aspect of the present invention, the locking flange provided on the edge of the annular seal member is locked on the edge of the receiving portion, so that a desired insertion amount can be obtained. Stop the annular sealing member.

Further, a plurality of pull-out preventing protrusions are provided on the annularly formed protrusion seal piece main body at predetermined intervals along the axial direction. Since the pull-out preventing projection has a tip inclined in the power cable protection tube insertion direction, the power cable protection tube can be easily inserted, and a good sealing property is obtained by dispersing a plurality of sealing portions. Can be

In addition, of the pull-out preventing projection pieces,
At least one of the power cable protective tubes is integrally formed with a fall prevention step that suppresses the fall of the protrusion seal piece body in the pull-out direction due to the pull-out of the power cable protection tube, and the fall of the protrusion seal piece body is suppressed. Thereby, the pull-out resistance increases and the power cable protective tube is prevented from falling off from the expansion joint.

According to the third aspect of the present invention, the tapered opening has an edge opening having a diameter smaller than a maximum diameter portion of the power cable protective tube.
When the expansion joints are bundled, there is no possibility that the expansion joints will interfere with other adjacent expansion joints in the vicinity of the fixed socket.

Therefore, there is a practically useful effect that an expansion joint that can be easily constructed and compactly housed in the handhole can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating an entire configuration of an expansion joint according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a water-resistant rubber member used for the expansion joint according to the first embodiment, showing an outer peripheral portion at a position along an axial direction.

FIG. 3 is a sectional view of an outer peripheral portion at a position along an axial direction of an annular seal member used for the expansion joint according to the first embodiment.

FIG. 4 is a conceptual diagram illustrating a state in which the expansion joints according to the first embodiment are bundled and attached to a handhole.

FIG. 5 is a side view of the pickaxe impact tester of the first embodiment.

FIG. 6 is a side view of a pickaxe-shaped tip of the pickaxe impact tester of the first embodiment.

FIG. 7 is a front view of a pickaxe-shaped tip of the pickaxe impact tester according to the first embodiment.

FIG. 8 is a partial cross-sectional view of a conventional expansion joint.

FIG. 9 is a sectional view of an outer peripheral portion at a position along an axial direction in a waterproof seal used for a conventional expansion joint.

FIG. 10 is a conceptual diagram illustrating a state in which a conventional expansion joint is bundled and attached to a handhole.

[Description of Signs] 2 Power cable protection tube 5 Hand hole 10 Expansion joint 10e Rubber ring receiving portion 10f Receiving portion 11 Annular seal member 12 First protrusion seal piece main body 13 Second protrusion seal piece main body 13b Fall prevention step 14 3 Projection seal piece main body 14b Fall prevention step 15 Fifth projection seal piece main body 16 Water-resistant rubber member 17 Fixed socket 17a Edge

Claims (3)

[Claims] 1. An expansion joint used for a connecting portion of a power cable protection tube, wherein the expansion joint has a diameter enlarged to a size capable of inserting an end of the power cable protection tube, and an end of the expansion joint body. While having approximately the same diameter from the edge to the inside of the pipe,
An annular seal member made of a rubber material so that the power cable protective tube is slidable is provided at a receiving portion provided with a rubber ring receiving portion to be mounted, and at an opposite edge of the receiving portion. An expansion joint having a watertight rubber and a fixed receiving portion for maintaining watertightness between the power cable protective tube to be connected thereto. 2. The power cable protective tube according to claim 2, further comprising: a locking flange portion provided at an edge of said annular sealing member for locking to an edge of said receiving portion; A plurality of pull-out preventing protrusions each having a tip inclined in the insertion direction are provided at predetermined intervals along the axial direction, and at least one of the pull-out preventing protrusions is provided with a pull-out direction by pulling out the power cable protective tube. The expansion joint according to claim 1, wherein a fall prevention step portion for suppressing the protrusion seal piece main body from falling down is integrally formed. 3. The expansion / contraction device according to claim 1, wherein the fixed receiving portion has a tapered opening shape having an edge opening portion having a smaller diameter than a maximum diameter portion of the expansion joint main body. Fittings.