JPH0926076A - Connection structure of corrugated pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure of a corrugated pipe which can eliminate an obstacle of a habit of winding and connect the corrugated pipe easily with good water stop property. SOLUTION: A rubber split sleeve 2 in which cuts are provided in the oblique direction for the radial direction of a cross section of a cylinder having an inner face 21 which has almost the same shape as an outer face of a corrugated pipe to be connected 1 over the whole length of the cylinder covers across both ends 11, 11 of the corrugated pipe, and each of a half of the rubber split sleeve 2 is tightened on the end 11 of the corrugated pipe by a tightening member 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrugated pipe connection structure.

[0002]

2. Description of the Related Art Corrugated pipes are excellent in flexibility and resistance to foot load, and are widely used as underground or indoor electric wire ducts, communication pipes for various buildings, and ventilation pipes. This corrugated pipe often has to be connected and used,
As the connection structure, particularly as the connection structure of the spiral corrugated pipe, a hard screw-type plastic sleeve having an inner surface having substantially the same shape as the outer surface of the corrugated pipe to be connected is screwed into one corrugated pipe end, and then , With the other corrugated pipe end abutting against this corrugated pipe end, the screwed plastic sleeves screwed in above are screwed back onto both corrugated pipe ends by reverse rotation, A structure in which each end of the tube and each corrugated pipe are sealed by wrapping a tape, etc., both corrugated pipe ends are butted,
When connecting the butt portion by tightening a two-piece clamp type joint, a structure in which a tubular rubber packing having an inner surface having substantially the same shape as the outer surface of the corrugated pipe to be connected is interposed (Japanese Utility Model Publication No. 5-16838), etc. Is known.

[0003]

In the above corrugated pipe, the corrugated pipe ends are curved because the corrugated pipe is transported in a state of being gripped or wound in a drum and is wound. Therefore, in the corrugated pipe connecting structure using the screw-in type plastic sleeve, the screw-in type plastic sleeve is screwed into the curved corrugated pipe end portion, or the other end of the curved sleeve is curved. In order to move the corrugated pipe end portion back to the screw, a large twisting torque that can return the curve of each corrugated pipe end to a straight line must be applied, and the operation is not easy.

On the other hand, in the connection structure using the above-mentioned two-piece tightening type joint, the rubber hardness is 1 to 2 in the tubular rubber packing.
Even if the end of the corrugated pipe is curved in the two-piece clamp type joint, a soft rubber such as No. 5 is used to ensure watertightness between the inner surface of the joint and the outer surface of the corrugated pipe due to the deformability of the soft rubber. Therefore, it is possible to eliminate the hindrance of the winding of the corrugated tube. However, as the hardness of the rubber becomes lower, the creep (deformation that gradually occurs over a long period of time) becomes more remarkable, so that it is difficult to guarantee stable water stoppage as long as the soft rubber is used. The object of the present invention is to eliminate the hindrance of winding and facilitate the corrugated tube,
Moreover, it is to provide a connecting structure for corrugated pipes that can be connected with good water shutoff.

[0005]

A corrugated pipe connecting structure according to the present invention has a notch extending in the radial direction of the cross section of a tubular body having an inner surface having substantially the same shape as the outer surface of the corrugated pipe to be connected. On the other hand, a rubber cracking sleeve placed diagonally was covered over both corrugated pipe ends, and each half of the rubber cracking sleeve was fastened to each corrugated pipe end by a tightening member. It is a structure characterized by that.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a corrugated pipe connection structure according to the present invention. In FIG. 1, reference numerals 1 and 1 denote tubes with spiral waves to be connected to each other (material is polyethylene,
It is a plastic such as polyvinyl chloride, a metal such as steel and aluminum, and both pipe ends are butted. Reference numeral 2 denotes a rubber crack sleeve, which has an inner surface 21 having a shape substantially equal to the outer surface of the corrugated tube 1 to be connected, and as shown in FIG. It is inserted in an oblique direction at an angle β and covers both corrugated pipe end portions 11, 11. Reference numeral 3 is a tightening member, and each half of the rubber crack sleeve 2 is tightened on each corrugated pipe end 11. As shown in FIG. 3, for example, as shown in FIG.
Open the metal C-shaped ring 31 with bolts and nuts 32.
Can be tightened with.

In order to assemble the above-mentioned corrugated pipe connecting structure, both corrugated pipes 1 and 1 to be connected are butted, and the above-mentioned rubber crack sleeve 2 is expanded and the elasticity thereof causes both corrugated pipe ends. Part 11,
After tying together over 11, the rubber cracking sleeve
Each half of the bush 2 is tightened with the tightening member 3, and the assembly is completed. In the above, if the spacing a between the tightening members 3 is made too wide, the cut 2 of the rubber crack sleeve 2
Since 2 is expanded by a relatively low internal pressure, the distance a is usually set to 30 mm or less.

If the oblique angle β of the cut 22 of the rubber cracking sleeve 2 is too small, it is difficult to guarantee sufficient water blocking performance, as is clear from the results of the water blocking test described later, and if it is too large, it is made of rubber. It becomes difficult to bind the split sleeve 2 to the above-mentioned corrugated pipe ends. Therefore, the oblique angle β is 25 ° ~
It is preferably 60 °. If the rubber hardness of the rubber cracking sleeve 2 is too high, the elastic modulus becomes too large to hinder the seal. If it is too low, the creep amount becomes large and the waterproofness is stable for a long time. Therefore, it is difficult to guarantee that the rubber hardness (JIS A hardness) is approximately 40. In particular, it is preferable that the rubber crack sleeve has a two-layer structure of a hard outer layer and a soft inner layer, and the outer layer has a hardness of 40 to 90 and the inner layer has a hardness of 1 to 60. In addition to the spiral corrugated tube, the present invention can be applied to a non-spiral corrugated tube in which annular convex portions and annular concave portions are alternately formed.

As is well known in material mechanics, the vertical stress δ of an oblique surface forming an angle β with respect to the vertical line direction of the principal stress surface (β = 90 °) is the principal stress (β = 90 ° If the normal stress on the surface is δ ₀ , it is given by δ = δ ₀ sin ² β. In FIG. 1, the vertical stress (contact pressure) at the cut surface of the rubber crack sleeve that is tightened by the tightening member 3 can be made sufficiently large by increasing δ ₀ in the equation by increasing the tightening force. , And β ≠ 0, it can be made sufficiently high. In addition, at the cut surface at the rubber crack sleeve between the tightening members, the surface pressure due to the tightening of the tightening members is substantially 0, but the surface pressure acts due to water pressure such as internal water pressure or external water pressure. The higher the water pressure, the higher the seal surface pressure, which is the so-called self-sealing action. Therefore, in spite of the presence of the break in the rubber crack sleeve, sufficient waterproofness is guaranteed.

In particular, when the rubber crack sleeve has a two-layer structure and the outer layer has a higher rubber hardness (about 40 to 90) and the inner layer has a lower rubber hardness (about 1 to 60) than the outer layer. Since the tightening force of the tightening member can be safely increased without damaging the rubber crack sleeve, and the watertightness of the interface between the rubber crack sleeve inner surface and the corrugated pipe outer surface can be increased. Higher waterproofness can be guaranteed. Even if the pipe end with corrugation to be connected is curved due to curling, the conjugation of the rubber crack sleeve across both pipe ends with corrugation does not affect the flexibility of the sleeve. In addition, since the width of the tightening member is narrow, mounting and tightening of the tightening member can be performed as easily as the straight corrugated pipe, and the connecting work can be performed by bending the end of the corrugated pipe to be connected. Can be performed with good workability.

[0011]

【Example】

[Example 1] In FIG. 1, the corrugated tube has an inner diameter of 80 mm.
φ, outer diameter 102 mmφ, corrugation pitch 25 mm, wall thickness 2
mm polyvinyl chloride pipe is used, and the rubber crack sleeve has an inner corrugated convex diameter of 84 mmφ, an inner corrugated concave diameter of 104 mmφ, and a wall thickness of 25 mm at the inner corrugated convex portion. Wall thickness 5 mm at corrugated concave portion, diagonal angle β of cut = 45 °, length 100 mm, rubber hardness 40
The injection-molded product is used, and the tightening member is made of iron and has a width of 30
The fastening hardware shown in FIG. The distance between the clamps was 15 mm. The end of the spirally wound polyvinyl chloride pipe had a winding curl with a winding diameter of 1400 mm, but the workability of the connecting work was good. In addition, when the waterproofness was tested by applying external water pressure, 2
No abnormality was observed even at kg / cm ² . In addition,
Even if the oblique angle β of the break of the rubber crack sleeve was 30 °, no abnormality was observed under an external water pressure of 2 kg / cm ² , but under the oblique angle β20 °, it was mild. Water leakage was observed, and it was confirmed that it is safe to set β to 25 ° or more from the viewpoint of water resistance.

[Embodiment 2] In FIG. 1, the corrugated pipe has an inner diameter of 65 mmφ, an outer diameter of 84 mmφ, and a corrugation pitch of 20 m.
A polyvinyl chloride tube with a spiral wave and a wall thickness of 2.1 mm was used. The rubber cracking sleeve is a two-layer type, the inner surface corrugated convex portion diameter is 70 mmφ, the inner surface corrugated concave portion diameter is 86 mm.
φ, wall thickness 21 mm at the inner surface corrugated convex portion, wall thickness 5 mm at the inner surface corrugated concave portion, outer layer rubber wall thickness 3.5 mm, cut oblique angle β = 45 °, length 100 mm, outer layer rubber hardness 80 An injection molded product having an inner rubber hardness of 20 was used.
As the fastening member, a fastening fitting made of iron and having a width of 30 mm shown in the figure was used. The distance between the clamps was 20 mm. The end of the spirally wound polyvinyl chloride pipe had a winding curl with a winding diameter of 1300 mm, but the workability of the connecting work was good. In addition, when the water pressure was applied to the inside to measure the water pressure when water leakage occurred, 5 kg /
cm ² .

Example 3 The same as Example 2 except that the oblique angle β of the break of the rubber crack sleeve was set to 30 °. When the water leakage water pressure was measured in the same manner as in Example 2, it was 4 kg / cm ² . In addition, when the angle β is set to 20 °, the water leakage water pressure becomes about 2 kg / cm ² , and it has been confirmed that it is safe to set β to 25 ° or more.

[Example 4] The same as Example 2 except that the inner layer rubber hardness was set to 60. Example 2
Water leak pressure was measured in the same manner as in 4 kg / c
m ² . In contrast to Example 2, if the rubber hardness of the entire rubber-made cracking sleeve is 80, the water leakage water pressure is 1 kg.
/ Cm ² and workability deteriorates. When the rubber crack sleeve is a single layer, the rubber hardness is 80.
It was confirmed that the following is appropriate.

[0015]

According to the corrugated pipe connection structure of the present invention, the corrugated pipe has a sufficiently high hardness (average hardness of about 30 to 60) even if the corrugated pipe end is curved due to curling. A corrugated pipe can be easily connected with a sufficiently high leakage water pressure by using a rubber breaking sleeve regardless of its curvature. Therefore, according to the present invention, it is possible to connect an electric wire duct in the ground or indoors or a corrugated pipe as a communication pipe or a ventilation pipe of various buildings with good workability, sufficiently high water stoppage and stable water stoppage.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a corrugated pipe connection structure according to the present invention.

FIG. 2 is a perspective view showing an example of a rubber crack sleeve used in the present invention.

FIG. 3 is a perspective view showing an example of a tightening member used in the present invention.

[Explanation of symbols]

 1 Corrugated pipe 11 Corrugated pipe end 2 Rubber crack sleeve 22 Cut 3 Clamping member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Shiga, 6th Danyo, Kakegawa, Shizuoka, Taiga Polymer Co., Ltd. Shizuoka factory (72) Inventor, Tetsuya Inakake, 6th, Tanyo, Kakegawa, Shizuoka − Inside Shizuoka factory

Claims (1)

[Claims] 1. A rubber cracking sleeve in which a notch is formed in the entire length of a cylindrical body having an inner surface having substantially the same shape as an outer surface of a corrugated pipe to be connected, the diagonal slit being oblique to the radial direction of the cylindrical body cross section. A corrugated pipe connection structure, characterized in that both ends of the corrugated pipe are covered, and each half of the rubber crack sleeve is fastened to each corrugated pipe end by a fastening member.