JP2879549B2 - Connection packing between underground concrete prefabricated pipe and cable protection pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to underground power transmission, power distribution,
This is related to the improvement of the connection packing used for the connection between the prefabricated underground concrete pipe and the cable protection pipe in the construction of conduits for communication lines and the like, with the aim of improving earthquake resistance.

[0002]

2. Description of the Related Art Conventionally, pipes used for underground facilities such as transmission and distribution cables and communication cables are constructed by sequentially connecting concrete prefabricated pipes having a plurality of cable insertion holes. Connections with manholes and locations where concrete prefabricated pipes cannot be used are connected using alternative cable protection steel pipes. The underground concrete prefabricated pipe and the cable protection steel pipe are connected by inserting the cable protection steel pipe into the insertion hole of the concrete prefabricated pipe, but the inside diameter of the concrete prefabricated pipe insertion hole and the outside of the cable protection steel pipe are connected. In order to cope with the difference in diameter from the diameter, as shown in FIG. 5, a vinyl tape 17 is wound around the outer periphery of the insertion port of the cable protection steel pipe 14 several times, and then inserted into the insertion hole 16 of the concrete prefabricated pipe 15. And the outer periphery of the fitting portion is covered with concrete 18 to ensure watertightness.

[0003] As another example, as shown in FIG.
In the cable insertion hole 16 of the concrete prefabricated pipe 15,
The front end of a metal joint pipe 19 formed in a large-diameter fitting opening 19b having an engagement step 19a and having a rear end that is widened is bonded in advance with a resin mortar 20 or the like. 19 is fitted with the cable protection steel pipe 14, and the distal end portion is engaged with the engagement step portion 19.
a, and was connected to the socket 19b with the packing 21 interposed.

[0004] The former requires time to wind the tape 17, and the latter requires time to bond the joint pipe 19 with the resin mortar 20. In addition, since the connection portion is not flexible in both cases, For example, there is a problem in that a connection part is damaged when a strong earthquake occurs and a force is applied in a vertical direction, a press-fit direction, or a pull-out direction.

[0005] In order to solve such problems,
A pipe connection socket described in Japanese Utility Model Publication No. 61-618 shown in FIG. 7 has been proposed. This pipe connection socket 22
Is a cylindrical rubber molded product having a front portion made of hard rubber and a rear portion made of soft rubber, and an engagement step portion 23 with which a front end portion of the cable protection steel tube 14 is formed is formed on an inner surface of the front portion. The distal end of the cable protection steel pipe 14 is engaged with the engaging step 23.

Since the pipe connection socket 22 does not take into consideration water tightness, the connection portion is often wound with concrete 24, and when wound with concrete, flexibility is lost, and it cannot withstand an earthquake having a large seismic intensity. Even when concrete is not wound, the flexibility of the socket is poor and the flexible angle is as small as about 3 degrees, and the length between the engagement step portion 23 and the tip end opening portion 22a of the socket 22 is short. When a large force is applied to the concrete prefabricated pipe 15, it breaks through the engaging step 23, hits the concrete prefabricated pipe 15 at the front, and breaks. Since the concrete prefabricated pipe 15 and the cable protection steel pipe 14 collide with each other when a large compressive force is applied thereto, the concrete protection prefabricated pipe 15 and the cable protection steel pipe 14 are damaged, so that they cannot withstand horizontal and vertical vibrations of seismic intensity 5 or more.

[0007]

SUMMARY OF THE INVENTION The present invention has been developed with the object of solving the above-mentioned problems. Even if a large earthquake having a seismic intensity of about 7 occurs, the concrete prefabricated pipe and the cable protection pipe can be used. It is an object of the present invention to provide a packing excellent in earthquake resistance used for a connection portion between a concrete prefabricated pipe and a cable protection steel pipe in which a connection portion is not damaged.

[0008]

Means for Solving the Problems As means for solving the above problems and achieving the object, in the present invention, the tip of a tapered cylindrical packing body is formed of hard rubber,
A portion from the rear to the rear end is made of soft rubber, and an engagement projection is provided on the inner peripheral surface slightly closer to the front end than the center, and a step is further provided on the inner peripheral surface of the front end. We have developed and adopted a packing for connecting a prefabricated underground concrete pipe and a cable protection pipe with fins provided on the outer peripheral surface of the part.

The present invention also relates to a connection packing between a prefabricated underground concrete pipe and a cable protection pipe constructed as described above, wherein about 1/4 of the length from the tip is formed of hard rubber, and the remaining about 3 / 4. The connection packing and the fin pieces of the prefabricated concrete underground pipe and the cable protection pipe each having a length of 4 made of soft rubber are composed of a plurality of pieces, and the fin pieces at the rear are formed larger than the fin pieces at the front. We have developed and adopted a packing for connecting underground concrete prefabricated pipes and cable protection pipes.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings 1 to 4. Reference numeral 1 denotes a rubber-made cylindrical packing body, which gradually moves from a front end to a rear end. It is formed in a tapered shape that expands. In this packing body 1, a portion A having a length of about 1/4 from the tip is H
s: 70 is formed of hard rubber, and the remaining portion B having a length of about 3/4 is formed of soft rubber of Hs: 40. By adopting this length ratio, the cable protection tube can be easily inserted, the holding force can be increased, and large flexibility and water solubility can be maintained.

Reference numeral 2 denotes an engagement protrusion provided on the inner peripheral surface of the soft rubber at a position slightly closer to the front end than the center of the packing body 1 and receives the front end of the cable protection steel pipe 5. Reference numeral 3 denotes a plurality of fin pieces provided on the outer peripheral surface of the rear end portion at a constant interval, and each fin piece 3 has an inclined side 3a and a vertical piece 3b.
And the inclined side 3a of the front fin 3 is 30
The inclined side 3a of the middle fin piece 3 is inclined at 35 degrees, and the inclined side 3a of the rear fin piece 3 is inclined at 45 degrees. The base is wide and the upper end is sharpened, The middle fin piece 3 is larger than the fin piece 3, and the fin piece 3c behind the middle fin piece 3 is larger. Reference numeral 4 denotes a step portion provided on the inner peripheral surface of the distal end portion, and has a size substantially equal to the outer diameter of the cable steel pipe 5.

FIG. 2 shows an example of use of the present invention configured as described above.
When the packing body 1 is fitted to the distal end of the cable protection steel pipe 5 and inserted into the cable insertion hole 7 of the concrete prefabricated pipe 6, the front outer peripheral surface of the packing body 1 contacts the cable insertion hole 7 and the rear part. Although a gap is formed in the enlarged hole 7a, the fin 3 is brought into contact with the gap and connected. In this connection work, when the cable protection steel pipe 5 is inserted into the cable insertion hole 7 of the prefabricated pipe 6, the tip is formed of hard rubber, so that it is easy to insert without causing a center shift, and the part of the fin piece 3 is formed. Is made of soft rubber, and as shown in FIG.
Can be smoothly inserted because the upper part of the slidably contacts the peripheral wall surface of the enlarged hole 7a and bends backward.

After the prefabricated concrete pipe 6 and the steel pipe 5 for cable protection have been joined, if an external force is applied in the pull-out direction due to, for example, an earthquake or the like, as shown in FIG. It turns in the direction and suppresses the peripheral wall of the enlarged hole 7a, so that it can be prevented from coming off. Therefore, even if a large earthquake occurs and a large force is applied in the pull-out direction and the cable protection steel pipe 5 moves about 10 cm in the pull-out direction, the function of the pipeline is not impaired at all.

On the other hand, when a large external force is applied in the pushing direction, the distal end of the cable protection steel pipe 5 engaged with the engaging projection 2 moves forward over the engaging projection 2 but the distal opening 1a. Since there is a distance, and the step 4 is provided at the tip, the step is received at the step 4 and the concrete prefabricated pipe 6 is not damaged. Since the engagement projection 2 is made of soft rubber, the cable protection steel pipe 5 does not climb over and be damaged. Further, when a force in the compression direction is received, the fin pieces 3 located in the enlarged hole 7a can sufficiently receive the force, and can be rotated 360 degrees at an angle of about 6 degrees. It is rich in flexibility, watertight and waterproof.

[0015]

As described above, according to the connection packing between the prefabricated underground concrete pipe and the cable protection pipe according to the first aspect of the present invention, the engaging projection is formed on the inner peripheral surface near the center or near the tip. Since it is provided, it is possible to prevent the cable protection tube from jumping out, and even if force is applied in the pushing direction and gets over the engagement protrusion and pushed in due to a large earthquake, there is a distance to the tip and there is a distance to the tip There is no step to break through the prefabricated concrete pipe.

Further, since the fin pieces are formed to project from the outer peripheral surface of the rear end of the packing, the connecting portion can be formed at an angle of about 6 degrees.
It can be freely rotated 0 degrees and the connection part is flexible without applying excessive force, so it can cope well even if force is applied up and down or left and right due to an earthquake etc. It does not damage the cable.

Further, according to the connection packing of the prefabricated underground concrete pipe and the cable protection pipe according to the second aspect of the present invention, the holding force can be increased without the center being shifted when the cable protection pipe is inserted, and The rear part has great flexibility and can be made watertight.

Further, according to the connection packing between the prefabricated underground concrete pipe and the cable protection pipe according to the third aspect of the present invention, greater flexibility is obtained and a complete watertight function is maintained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a packing of the present invention.

FIG. 2 is a vertical sectional side view showing a use state.

FIG. 3 is an enlarged sectional view of a main part when a force is applied in a pushing direction.

FIG. 4 is an enlarged sectional view of a main part when a force is applied in a pulling-out direction.

FIG. 5 is a longitudinal sectional side view showing a connection portion of a conventional example.

FIG. 6 is a vertical sectional side view showing another conventional connection portion.

FIG. 7 is a vertical sectional side view showing still another conventional connection portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packing main body 2 Engagement protrusion 3 Fin piece 4 Cable protection tube 5 Concrete prefabricated tube

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ichi Taniguchi 5-14-10 Nishitenma, Kita-ku, Osaka City Inside Kinki Concrete Industries Co., Ltd. (72) Inventor Shizuhiro Nakata 5-14-10 Nishitenma, Kita-ku, Osaka-shi Kinki Concrete Industry Co., Ltd. (56) References JP-A-50-82621 (JP, A) JP-A-5-203084 (JP, A) JP-A-60-45991 (JP, U) JP-A-29-3004 (JP, Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16L 13/00-25/02

Claims (3)

(57) [Claims] 1. A tapered tapered cylindrical packing body having a front end formed of hard rubber, a rear end formed of soft rubber, and an engagement projection formed on an inner peripheral surface slightly closer to the front end than the center. A packing for connecting an underground concrete prefabricated pipe and a cable protection pipe, wherein a projecting portion is provided, a step is further provided on an inner peripheral surface of a front end portion, and a fin is provided on an outer peripheral surface of a rear end portion. 2. The prefabricated underground concrete pipe according to claim 1, wherein about 1/4 of the length from the tip is formed of hard rubber, and about 3/4 of the remaining length is formed of soft rubber. And cable protection tube connection packing. 3. A fin piece comprising a plurality of fin pieces, wherein a rear fin piece is formed larger than a front fin piece.
The packing for connecting a prefabricated underground concrete pipe and a cable protection pipe according to the above item.