JP2004332895A

JP2004332895A - Pipe joint

Info

Publication number: JP2004332895A
Application number: JP2003132907A
Authority: JP
Inventors: Naoto Wada; 直人和田; Katsuhiko Shirogane; 克彦白銀; Takeshi Terasaka; 剛寺阪
Original assignee: Furukawa Electric Co Ltd; Kyowa Rubber KK
Current assignee: Furukawa Electric Co Ltd; Kyowa Rubber KK
Priority date: 2003-05-12
Filing date: 2003-05-12
Publication date: 2004-11-25
Anticipated expiration: 2023-05-12
Also published as: JP4267964B2

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the connection of a pipe body with a pipe joint even in the case that the pipe body tends to bend because the joint body can be easily attached and removed by forming the almost equal clearance between the outer circumference face of the pipe body and the water stop layer and the handling performance of the joint body is improved when the pipe body is connected with the joint body: to provide the pipe joint capable of obtaining a certain water stop effect by the quick expansion of absorb water in the water stop layer securing the water passage where makes the water and moisture enter positively by the above clearance. <P>SOLUTION: In the pipe joint 1 having the joint body 3 that connects the end part of the pipe body 6, 8 with a spiral uneven thread 5, 7, the water stop layer 4 is provided on an inner circumference face of the above joint body 3 and the almost equal clearance C is formed between an outer circumference face of the pipe body 6, 8 and the water stop layer 4 when the pipe body 6, 8 is connected to the above joint body 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、地中に埋設されて電線やケーブルなどを保護する管体相互を接続するような管継手に関する。
【０００２】
【従来の技術】
一般に上述例の電線またはケーブル保護用の管体、および管体相互を接続する管継手は地中に埋設される関係上、特に管体と管継手との間には確実な防水構造、止水構造が要求される。
【０００３】
従来、このような要求に対応して各種の管継手が既に発明されている。
すなわち、管継手の中央に中央筒を有し、この中央筒の一側および他側にそれぞれ短管部を回動自在に接続すると共に、一側の短管部には断面が台形状の螺旋凹凸条を一体形成し、他側の短管部には断面が半円形の螺旋凹凸条を一体形成し、これら両短管部の内周面に水密封止用繊維シート（いわゆる止水層）を融着一体化した水密封止シート付き管継手がある（特許文献１参照）。
【０００４】
また、管継手の中央に中央部分形成用の短筒を有し、この中央部の短筒の一側および他側にそれぞれ左右両端部形成用の短筒を回動自在に接続すると共に、一側の短筒には断面が台形状の螺旋凹凸条を一体形成し、他側の短筒には断面が半円形の螺旋凹凸条を一体形成し、これら両端部の短筒の内周面または外周面にシート状の水密シール体（いわゆる止水層）を貼着一体化した螺旋波形管用の管継手がある（特許文献２参照）。
【０００５】
さらに、管体の端部を差し込んで接続する接続部を有した合成樹脂製またはゴム製の管継手において、接続部における管体との対向面に、水分を吸収して膨張する膨張体（いわゆる止水層）を一体成形した管継手がある（特許文献３参照）。
【０００６】
【特許文献１】
実公平７−５２４６７号公報（実用新案登録第２１３３７０６号公報）
【特許文献２】
実公平８−９５１０号公報（実用新案登録第２１４６２１７号公報）
【特許文献３】
特開２００２−３３３０８６号公報。
【０００７】
【発明が解決しようとする課題】
これらの各従来公報に開示された管継手を管体（いわゆるパイプ）に接続した時、管体の外周面と、水密封止用繊維シート、水密シート体または膨張体のいわゆる止水層との間には一切クリアランスが形成されないように構成されているので、管継手で管体を接続する際の操作力が必要以上に大となり、接続操作性が悪い問題点があった。
【０００８】
また上記管体は一般に巻回して保管され、この管体に曲がりぐせが付いている場合には、管体と管継手との接続が困難となる問題点があった。
【０００９】
そこで、この発明は、継手本体で管体を接続した時、管体外周面と止水層との間にほぼ均等なクリアランスを形成することで、継手本体の取付け取外しが容易となり、継手本体の接続操作性が向上し、管体に曲がりぐぜが付いている場合にも管体と管継手との接続が容易なうえ、上記クリアランスにより水、水分を積極的に浸入させる水通路を確保して、止水層の迅速な吸水膨張により確実な止水効果を得ることができる管継手の提供を目的とする。
【００１０】
【課題を解決するための手段】
この発明による管継手は、螺旋凹凸条を有する管体の端部を接続する継手本体を備えた管継手であって、上記継手本体の内周面には止水層が設けられ、上記継手本体で管体を接続した時、管体外周面と止水層との間にほぼ均等なクリアランスが形成されたものである。
【００１１】
上記構成の止水層は、水を吸収して膨張することにより管体と継手本体との間を止水するものである。また上記クリアランスは管体外径に対応して０．２ｍｍ〜５．０ｍｍの任意の値に設定してもよい。
【００１２】
上記構成によれば、ほぼ均等なクリアランスを形成したので、継手本体の取付け取外しが容易となり、継手本体の接続操作性が向上し、管体に曲がりぐせが付いている場合においても上記クリアランスにより管体と管継手との接続が容易となるうえ、該クリアランスにより水、水分を積極的に浸入させる水通路を確保して、止水層の迅速な吸水膨張により確実な止水効果を得ることができる。
【００１３】
この発明の一実施態様においては、上記止水層を含む継手本体の内径を、管体の螺旋凹凸条の山部の外径で除した値が１．０未満に設定されたものである。
上記構成の止水層を含む継手本体の内径をＤ１、管体に螺旋凹凸条の山部の外径をＤ２とする時、（Ｄ１／Ｄ２）＜１．０に設定するものであり、（Ｄ１／Ｄ２）＝αとする時、この値αは望ましくは０．７５＜α＜１に設定、さらに望ましくは０．８０＜α＜０．９０に設定、さらに望ましくは０．８２＜α＜０．８８に設定してもよい。
【００１４】
上記構成によれば、上述の値αを１．０未満に設定したので、継手本体で管体を確実に接続することができる。
【００１５】
この発明の一実施態様においては、上記継手本体には管体の螺旋凹凸条に螺合される螺旋状の突条が一体形成され、継手本体で管体を接続した時、継手本体の径方向内方への螺旋突条の凸部端と、管体の螺旋凹凸条の隣接する山部端とが径方向にオーバラップするものである。
【００１６】
上記構成によれば、継手本体の径方向内方への螺旋突条の凸部端（但し、止水層を含まない状態の凸部端）と、管体の螺旋凹凸条の隣接する山部端とが径方向にオーバラップするので、充分な引張り強度（引抜き強度）を確保することができる。
【００１７】
この発明の一実施態様においては、上記継手本体の外周側には接続操作用の突起部が設けられたものである。
上記構成の突起部は１つ、または複数を継手本体の外周側に一体形成してもよい。
【００１８】
上記構成によれば、突起部により接続操作時に作業者の手が滑るのを防止することができ、この結果、管継手の取付け、取外し操作の容易化を図ることができる。
【００１９】
この発明の一実施態様においては、上記継手本体の軸方向における螺旋状の突条の数が２〜８に設定されたものである。
上記構成によれば、管体と継手本体との接続時における引張り強度の確保と作業性向上との両立を図ることができる。つまり突条の数が２未満の場合には引張強度が得られず、逆に突条の数が８を超過する場合には接続時の作業性が悪化し、特に管体に曲がりぐせが付いている場合には接続が困難となるので、上記突条の数を２〜８、望ましくは２．５〜７．５に設定することにより、引張り強度の確保と作業性向上との両立を図ることができる。
【００２０】
【実施例】
この発明の一実施例を以下図面に基づいて詳述する。
図面は管継手を示し、図１、図２において、この管継手１は径方向内方へ突出する凸部２ａと、外周部を形成する凹部２ｂとから成る連続した螺旋凹凸条２を有する合成樹脂製または合成ゴム製の継手本体３の内周面全域にほぼ均一厚さの止水層４が一体化されたものであって、図２に示す山部５ａと谷部５ｂとから成る螺旋凹凸条５を有する一方の管体６（いわゆるパイプ）と、山部７ａと谷部７ｂとから成る螺旋凹凸条７を有する他方の管体８（いわゆるパイプ）とを接続するものである。
【００２１】
すなわち、管継手１の他方の端部１Ａが一方の管体６の端部６Ａと一致するまで該管継手１を管体６にねじ込み接続し、次に管体６の端部６Ａと他方の管体８の端部８Ａとを一致または略一致させた後に、一旦ねじ込んだ管継手１をねじ込み量の約半分ねじ戻すことにより、管継手１の他方を管体８にねじ込み接続して、図３に示すように該管継手１で双方の管体６，８を接続するものである。
【００２２】
図３に示すように管継手１の継手本体３の内周面に一体化された止水層４と各管体６，８の外周面との間には、該止水層４が水を吸水して膨張する以前と、水膨張後の乾燥時（水分放出時）においては、水流通用（水浸入用）のクリアランスＣ（いわゆる水の通路）が均等または略均等に形成されている。
【００２３】
これら管体６，８および管継手１は、管体６，８の内部に電線やケーブルなどを挿通させた状態で地中に埋設されるものであって、止水層４が水を吸水すると、図３に示す状態から図４に示すように、この止水層４、特に管継手１の両端部側の部分が膨張して、この吸水膨張により止水層４で継手本体３と各管体６，８の外周面との間を液密性に封止することにより、確実な止水効果を発揮するものである。
【００２４】
図３、図４では継手本体３の軸方向における螺旋状の突条つまり凸部２ａの数が「４〜６」の一例としての「５」の場合を例示したが、このように凸部２ａの数を「４〜６」に設定すると、管継手１の装着時に図５、図６に示すように端部６Ａ，８Ａの位置が何れか一方に片寄っても、適切な液密性の確保と引っ張り強度の確保との両立を図ることができる。なお、図５は止水層４の吸水以前および乾燥時の状態を示し、図６は止水層４が水を吸水して膨張した止水時の状体を示す。
【００２５】
図７、図８は継手本体３の軸方向における螺旋状の突条つまり凸部２ａの数を「２以上」の一例としての「２．５」に設定した場合を示し、この場合、管継手１の装着時に端部６Ａ，８Ａの位置が継手本体３における軸方向の中央または略中央に位置すると、適切な液密性の確保と引っ張り強度の確保との両立を図ることができるうえ、ねじ込み量、ねじ戻し量が最小となり、接続操作性が向上する。なお、図７は止水層４の吸水以前および乾燥時の状態を示し、図８は止水層４が水を吸水して膨張した止水時の状態を示す。
【００２６】
図９、図１０は継手本体３の軸方向における螺旋状の突条つまり凸部２ａの数を「７〜８」の一例としての「８」に設定した場合を示し、この場合、管継手１の装着時に同図に示すように端部６Ａ，８Ａの位置が何れか一方に片寄っても、適切な液密性の確保と引っ張り強度の確保との両立を図ることができ、かつ図３〜図８の実施例と比較して、引っ張り強度をさらに向上させることができる。なお、図９は止水層４の吸水以前および乾燥時の状態を示し、図１０は止水層４が水を吸水して膨張した止水時の状態を示す。
【００２７】
要するに、上記凸部２ａの数が「２」未満の場合には引張り強度が得られず、逆に凸部２ａの数が「８」を超過する場合にはねじ込み量およびねじ戻し量の過多に起因して接続時の作業性が悪化し、特に管体６または８に曲がりぐせが付いている場合には接続が困難となるので、上述の凸部２ａの数を図３〜図１０で示した「２〜８」の範囲内、望ましくは「２．５〜７．５」の範囲内に設定することにより、引張り強度の確保と作業性向上との両立を図るように構成したものである。
【００２８】
図１１は止水層４の吸水以前および乾燥時（水分放出時）の部分拡大断面図であって、止水層４を含む継手本体３の内径つまり径方向内方へ突出する凸部２ａの内径をＤ１、管体６（図１１では図示の便宜上、一方の管体６のみを示すが、他方の管体８についても同様）の螺旋凹凸条５の山部５ａの外径をＤ２とし、Ｄ１／Ｄ２＝αとする時、この値αは１．０未満、望ましくは０．７５＜α＜１に設定、さらに望ましくは０．８０＜α＜０．９０に設定、さらに望ましくは０．８２＜α＜０．８８に設定されている。
【００２９】
つまりα＝１の場合には管継手１で管体６，８を接続した時の引っ掛かりがなく、引張り強度が確保できず、α＝０．７５未満の場合には管体６，８の寸法に製造ばらつきがあった場合に接続性が悪化するので、０．７５＜α＜１に設定することで、接続性の容易化を図りつつ、適切な引張り強度を確保するものである。
【００３０】
また、０．８０＜α＜０．９０に設定すると、接続性の向上を図りつつ、充分な引張り強度を確保することができ、０．８２＜α＜０．８８に設定すると、接続性のさらなる向上を図りつつ、引張り強度の向上を確保することができる。
【００３１】
しかも、図１１に示すように、継手本体３には管体６，８の螺旋凹凸条５，７に螺合される螺旋凹凸条２が一体形成され、同図に示すように継手本体３で管体６，８を接続した時、継手本体３の径方向内方への螺旋突条の凸部２ａの内端（但し、この場合は止水層４を含まない状態の凸部２ａの内端）と、管体６，８の螺旋凹凸条５，７の隣接する山部５ａ，７ａの外端とが径方向に所定量Ｗオーバラップすべく構成している。
【００３２】
このオーバラップ量Ｗは管体６，８の外径Ｄ２に対応して任意の値に設定することができ、このオーバラップ構造により管継手１の充分な引張り強度（引抜き強度）を確保することができる。
【００３３】
図１２は図３のＸ−Ｘ線矢視断面図であって、継手本体３の外周側には接続操作用の少なくとも１つの突起部９（図面では１８０度の開角をもち、継手本体３の軸方向全長にわたって一体形成された合計２つの突条を示す）が設けられている。
【００３４】
そして、これらの突起部９，９により管継手１で管体６，８を接続する取付け時、または管継手１を管体６，８から取外す取外し時において、作業者の手が滑るのを防止し、これにより管継手１の取付け、取外し操作の容易化を図るように構成している。さらに、これら突起部９，９は図１に示すように継手本体３の螺旋凹凸条２における凸部２ａと凹部２ｂとの外面に沿って一体形成されるので、特に凸部２ａの変形が突起部９により防止され、この結果、引張り強度がさらに向上する。
【００３５】
図１３、図１４は止水層４の詳細構造を示す拡大図であって、まず、不織布の基材となるＰＥＴなどの樹脂製の基材繊維１０約１０〜２５ｗｔ％と、高融点水膨張樹脂材が繊維化された水膨張繊維１１（吸水時に膨張すると共に、周囲の湿度が低い時に水分を開放する繊維）約７０〜９０ｗｔ％と、低融点ＰＥＴなどのバインダ１２（詳しくはバインダ樹脂）約２〜１５ｗｔ％とを用い、これらをほぼ均等に混合して不織布を形成する（不織布形成工程）。
【００３６】
ここで上述の水膨張繊維１１としては、その軟化点が約１７０℃のベルオアシス（登録商標・カネボウ合繊株式会社製品であって、ポリアクリル酸ナトリウム塩を主成分とするポリマーを直接紡糸し、繊維形状化させた高吸水、高吸湿繊維）を用いる。またバインダ１２としては軟化点が約１２０℃の低融点のものを使用する。
【００３７】
次に、偏平な不織布を円筒状と成して内金型（詳しくは複数分割構造で、かつ螺旋凹凸条を形成する形状面をもった内金型）に被着し、この不織布の外周側に半割り構造の外金型（詳しくは螺旋凹凸条を形成する形状面をもった外金型）を配置し、外金型内面と不織布外周面との間に継手本体３を形成する溶融状態の合成樹脂または合成ゴムを充填して、外金型を型締めして成形温度約１５０〜１８０℃で加熱、加圧すると、この加工時の熱によりバインダ１２が溶融し、図１３に示すように溶融したバインダ１２で基材繊維１０と水膨張繊維１１とが強固に結合（バインダによる結合工程）された止水層４となり、この止水層４は継手本体３に一体化（一体化工程）されるので、型ばらし後においては図１に示す管継手１となる。
【００３８】
上述の止水層４における水膨張繊維１１は吸水時に径方向へ膨張して図１４の状態となって止水効果を発揮するが、この時、水膨張繊維１１はバインダ１２により基材繊維１０に強固に結合されているので、吸水前、吸水後の何れにおいても該水膨張繊維１１の不織布の基材からの脱落を防止することができる。
【００３９】
なお、上述の高融点水膨張樹脂材が繊維化された水膨張繊維１１に代えて、低融点水膨張樹脂材が繊維化された水膨張繊維（例えば、軟化点が約１２０℃のランシール、登録商標・東洋紡績株式会社製品）を用いると、バインダが一切不要となり、この水膨張繊維それ自体がバインダの機能をはたす。つまり水膨張繊維が加工時の熱で溶融して基材繊維１０に強固に結合される。
【００４０】
また不織布に対して液状の吸水性樹脂（例えば、エクオス（商標）、サンアッド株式会社製品）を含浸させたものを用いて止水層４を成形してもよい。何れにしても、水膨張繊維または吸水性樹脂の基材繊維１０からの脱落がほとんどなくなるので、止水層４が水分を放出して元の状態に戻った時、一度使用した管継手１を一旦、取外して再度使用することができ、この結果、管継手１の再使用（繰返し使用）を達成することができる。
【００４１】
図１〜図１４の実施例においては継手本体３を合成樹脂で形成したが、この継手本体３は図１５に示すように合成ゴムで形成してもよく、または図１６に示すように継手本体３の外周部に溝部を有さない外周フラット形状に構成してもよい。
【００４２】
このように上記実施例の管継手は、螺旋凹凸条５，７を有する管体６，８の端部を接続する継手本体３を備えた管継手１であって、上記継手本体３の内周面には止水層４が設けられ、上記継手本体３で管体６，８を接続した時、管体６，８外周面と止水層４との間にほぼ均等なクリアランスＣが形成されたものである。
【００４３】
この止水層４は、水を吸収して膨張することにより管体６，８と継手本体３との間を止水するものである。また上記クリアランスＣは管体６，８の外径に対応して０．２ｍｍ〜５．０ｍｍの任意の値に設定することができる。
【００４４】
この構成によれば、ほぼ均等なクリアランスＣを形成したので、継手本体３の取付け取外しが容易となり、継手本体３の接続操作性が向上し、管体６または，８に曲がりぐせが付いている場合においても上記クリアランスＣにより管体６，８と管継手１との接続が容易となるうえ、該クリアランスＣにより水、水分を積極的に浸入させる水通路を確保して、吸水時には止水層４の迅速な吸水膨張により確実な止水効果を得ることができる。さらに、上記クリアランスＣの形成により止水層４に用いられる水膨張繊維や吸水性樹脂の機械的外力による脱落防止を図ることができるので、管継手１の耐久性向上を図ることができる。
【００４５】
また、上記止水層４を含む継手本体３の内径Ｄ１を、管体６，８の螺旋凹凸条の山部の外径Ｄ２で除した値αが１．０未満に設定されたものである。
この構成によれば、上述の値αを１．０未満に設定したので、継手本体３で管体６，８を確実に接続することができる。
【００４６】
しかも、上記継手本体３には管体６，８の螺旋凹凸条５，７に螺合される螺旋状の突条（螺旋凹凸条２参照）が一体形成され、継手本体３で管体６，８を接続した時、継手本体３の径方向内方への螺旋突条の凸部２ａ端と、管体６，８の螺旋凹凸条５，７の隣接する山部５ａ，７ａ端とが径方向にオーバラップ（オーバラップ量Ｗ参照）するものである。
【００４７】
この構成によれば、継手本体３の径方向内方への螺旋突条の凸部２ａ端（但し、止水層４を含まない状態の凸部２ａ端）と、管体６，８の螺旋凹凸条５，７の隣接する山部５ａ，７ａ端とが径方向にオーバラップするので、充分な引張り強度（引抜き強度）を確保することができる。
【００４８】
さらに、上記継手本体３の外周側には接続操作用の突起部９が設けられたものである。
この構成によれば、突起部９により接続操作時に作業者の手が滑るのを防止することができ、この結果、管継手１の取付け、取外し操作の容易化を図ることができる。
【００４９】
加えて、上記継手本体３の軸方向における螺旋状の突条の数（凸部２ａの数参照）が２〜８に設定されたものである。
この構成によれば、管体６，８と継手本体３との接続時における引張り強度の確保と作業性向上との両立を図ることができる。つまり凸部２ａの数が２未満の場合には引張強度が得られず、逆に凸部２ａの数が８を超過する場合には接続時の作業性が悪化し、特に管体６，８に曲がりぐせが付いている場合には接続が困難となるので、上記凸部２ａの数を２〜８、望ましくは２．５〜７．５に設定することにより、引張り強度の確保と作業性向上との両立を図ることができる。
【００５０】
この発明の構成と、上述の実施例との対応において、
この発明の、螺旋突条は、実施例の螺旋凹凸条２に対応し、
以下同様に、
螺旋状の突条の数は、凸部２ａの数に対応するも、
この発明は、上述の実施例の構成のみに限定されるものではない。
【００５１】
【発明の効果】
この発明によれば、継手本体で管体を接続した時、管体外周面と止水層との間にほぼ均等なクリアランスを形成したので、継手本体の取付け取外しが容易となり、継手本体の接続操作性が向上し、管体に曲がりぐぜが付いている場合にも管体と管継手との接続が容易なうえ、上記クリアランスにより水、水分を積極的に浸入させる水通路を確保して、吸水時には止水層の迅速な吸水膨張により確実な止水効果を得ることができる管継手の提供を目的とする。
【図面の簡単な説明】
【図１】本発明の管継手の斜視図。
【図２】管継手および管体の斜視図。
【図３】管継手による管体の接続状態を示す断面図。
【図４】止水時の断面図。
【図５】管体突き合わせ部が一方に片寄った状態の断面図。
【図６】図５の構造の止水時の断面図。
【図７】管継手の他の実施例を示す断面図。
【図８】図７の構造の止水時の断面図。
【図９】管継手のさらに他の実施例を示す断面図。
【図１０】図９の構造の止水時の断面図。
【図１１】管継手と管体との寸法関係を示す拡大断面図。
【図１２】図３のＸ−Ｘ線矢視断面図。
【図１３】止水層のバインダによる結合状態を示す説明図。
【図１４】繊維膨張時の説明図。
【図１５】管継手のさらに他の実施例を示す部分拡大断面図。
【図１６】管継手のさらに他の実施例を示す部分拡大断面図。
【符号の説明】
１…管継手
２…螺旋凹凸条（螺旋突条）
２ａ…凸部
３…継手本体
４…止水層
５，７…螺旋凹凸条
５ａ，７ａ…山部
６，８…管体
９…突起部
Ｃ…クリアランス
Ｄ１…継手本体の内径
Ｄ２…山部の外径[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint that connects pipes that are buried underground to protect electric wires and cables.
[0002]
[Prior art]
Generally, the pipes for protecting electric wires or cables and the pipe joints connecting the pipes described above are buried in the ground, and particularly, a reliable waterproof structure and water stoppage are provided between the pipes and the pipe joints. Structure is required.
[0003]
Conventionally, various pipe joints have already been invented in response to such demands.
That is, the pipe joint has a center tube at the center, and a short tube portion is rotatably connected to one side and the other side of the center tube, and the short tube portion on one side has a trapezoidal spiral. An uneven strip is integrally formed, and a spiral uneven strip having a semicircular cross section is integrally formed in the short pipe part on the other side, and a water-tight sealing fiber sheet (a so-called water-stop layer) is formed on the inner peripheral surface of both short pipe parts. (See Patent Document 1).
[0004]
In addition, a short tube for forming a central portion is provided at the center of the pipe joint, and short tubes for forming left and right end portions are rotatably connected to one side and the other side of the short tube in the central portion, respectively. In the short cylinder on the side, a spiral concave / convex strip having a trapezoidal cross section is integrally formed, and in the short cylinder on the other side, the spiral concave / convex strip having a semicircular cross section is integrally formed. There is a pipe joint for a spiral corrugated pipe in which a sheet-like watertight seal (so-called water-blocking layer) is attached and integrated on the outer peripheral surface (see Patent Document 2).
[0005]
Furthermore, in a synthetic resin or rubber pipe joint having a connecting portion for inserting and connecting an end portion of a pipe, an inflatable body (so-called expanded body) that absorbs moisture and expands on a surface of the connecting portion facing the pipe. There is a pipe joint in which a water blocking layer is integrally formed (see Patent Document 3).
[0006]
[Patent Document 1]
Japanese Utility Model Publication No. 7-52467 (utility model registration No. 2133706)
[Patent Document 2]
Japanese Utility Model Publication No. 8-9510 (Utility Model Registration No. 2146217)
[Patent Document 3]
JP-A-2002-333086.
[0007]
[Problems to be solved by the invention]
When the pipe joint disclosed in each of these conventional publications is connected to a pipe (so-called pipe), the outer peripheral surface of the pipe and the so-called water-blocking layer of the watertight sealing fiber sheet, watertight sheet or expanded body are connected. Since no clearance is formed between the pipes, the operating force for connecting the pipes with the pipe joints is unnecessarily large, and the connection operability is poor.
[0008]
In addition, the above-mentioned pipe is generally wound and stored, and when the pipe is bent, there is a problem that it is difficult to connect the pipe to the pipe joint.
[0009]
Therefore, the present invention, when the pipe body is connected with the joint body, by forming a substantially uniform clearance between the outer peripheral surface of the pipe body and the water blocking layer, the attachment and detachment of the joint body becomes easy, and the joint body is removed. Connection operability is improved, connection between the pipe body and the pipe joint is easy even when the pipe body has a bend, and the above clearance secures a water passage that allows water and moisture to penetrate actively It is another object of the present invention to provide a pipe joint capable of obtaining a reliable water stopping effect by rapid water expansion of a water stopping layer.
[0010]
[Means for Solving the Problems]
A pipe joint according to the present invention is a pipe joint provided with a joint main body for connecting ends of a pipe having a spiral uneven strip, wherein a water-stop layer is provided on an inner peripheral surface of the joint main body, When the pipe is connected by the above, a substantially uniform clearance is formed between the outer peripheral surface of the pipe and the water blocking layer.
[0011]
The water-stop layer having the above structure absorbs water and expands to stop water between the pipe and the joint body. The clearance may be set to an arbitrary value of 0.2 mm to 5.0 mm corresponding to the outer diameter of the tube.
[0012]
According to the above configuration, since a substantially uniform clearance is formed, attachment and detachment of the joint body becomes easy, connection operability of the joint body is improved, and even when the pipe body is bent, the pipe is formed by the clearance. In addition to facilitating the connection between the body and the pipe joint, the clearance can secure a water passage through which water and moisture can infiltrate, and a reliable water stopping effect can be obtained by rapid water absorption expansion of the water stopping layer. it can.
[0013]
In one embodiment of the present invention, the value obtained by dividing the inner diameter of the joint main body including the water blocking layer by the outer diameter of the ridge of the spiral uneven strip of the pipe is set to less than 1.0.
(D1 / D2) <1.0, where D1 is the inner diameter of the joint body including the water blocking layer having the above-described configuration, and D2 is the outer diameter of the ridge of the spiral uneven strip on the pipe body. When D1 / D2) = α, this value α is preferably set to 0.75 <α <1, more preferably 0.80 <α <0.90, and more preferably 0.82 <α <. It may be set to 0.88.
[0014]
According to the above configuration, the value α is set to less than 1.0, so that the pipe can be reliably connected to the joint body.
[0015]
In one embodiment of the present invention, the joint main body is integrally formed with a helical ridge that is screwed into the helical uneven ridge of the pipe, and when the pipe is connected with the joint main body, the radial direction of the joint main body is changed. The projecting end of the inward spiral ridge and the adjacent mountain end of the spiral ridge of the tube overlap in the radial direction.
[0016]
According to the above configuration, the convex end of the spiral ridge inwardly in the radial direction of the joint body (however, the convex end in a state that does not include the water blocking layer), and the adjacent ridge of the spiral concave and convex stripe of the pipe body. Since the ends overlap in the radial direction, sufficient tensile strength (pull-out strength) can be ensured.
[0017]
In one embodiment of the present invention, a projection for connection operation is provided on the outer peripheral side of the joint body.
One or more of the protrusions having the above configuration may be integrally formed on the outer peripheral side of the joint body.
[0018]
According to the above configuration, the protrusion can prevent the worker's hand from slipping during the connection operation, and as a result, the attachment and detachment operation of the pipe joint can be facilitated.
[0019]
In one embodiment of the present invention, the number of spiral ridges in the axial direction of the joint body is set to 2 to 8.
According to the above configuration, it is possible to ensure both tensile strength and improved workability at the time of connection between the tubular body and the joint body. In other words, when the number of ridges is less than 2, tensile strength cannot be obtained, and when the number of ridges exceeds 8, the workability at the time of connection deteriorates, and especially, the pipe body is bent. In such a case, the connection becomes difficult. Therefore, by setting the number of the ridges to 2 to 8, preferably 2.5 to 7.5, it is possible to ensure both tensile strength and workability. be able to.
[0020]
【Example】
An embodiment of the present invention will be described below in detail with reference to the drawings.
The drawings show a pipe joint. In FIGS. 1 and 2, this pipe joint 1 has a continuous spiral uneven strip 2 composed of a convex portion 2a projecting radially inward and a concave portion 2b forming an outer peripheral portion. A water-stop layer 4 having a substantially uniform thickness is integrated over the entire inner peripheral surface of a resin or synthetic rubber joint body 3, and is formed by a spiral including a peak portion 5a and a valley portion 5b shown in FIG. The one pipe 6 (so-called pipe) having the uneven ridges 5 is connected to the other pipe 8 (so-called pipe) having the spiral uneven ridges 7 composed of the peaks 7a and the valleys 7b.
[0021]
That is, the pipe joint 1 is screwed and connected to the pipe 6 until the other end 1A of the pipe joint 1 coincides with the end 6A of one pipe 6, and then the end 6A of the pipe 6 and the other end are connected. After the end 8A of the pipe 8 is matched or substantially matched, the screwed pipe joint 1 is unscrewed by about half of the screwed amount, so that the other end of the pipe joint 1 is screwed into the pipe 8 and connected. As shown in FIG. 3, both pipes 6, 8 are connected by the pipe joint 1.
[0022]
As shown in FIG. 3, between the water-stop layer 4 integrated with the inner peripheral surface of the joint main body 3 of the pipe joint 1 and the outer peripheral surfaces of the pipe bodies 6, 8, the water-stop layer 4 allows water to flow. Before the water is expanded by absorbing water, and at the time of drying (at the time of releasing moisture) after the water expansion, the clearance C (so-called water passage) for water distribution (for water intrusion) is formed evenly or substantially evenly.
[0023]
These pipes 6, 8 and the pipe joint 1 are buried underground with electric wires, cables, etc. inserted through the pipes 6, 8, and when the water-stop layer 4 absorbs water. As shown in FIG. 4 from the state shown in FIG. 3, the water-stopping layer 4, particularly the portions on both ends of the pipe joint 1, expands, and the water-absorbing expansion causes the water-stopping layer 4 to connect the joint body 3 and each pipe. By sealing between the outer peripheral surfaces of the bodies 6 and 8 in a liquid-tight manner, a reliable water stopping effect is exhibited.
[0024]
3 and 4 illustrate the case where the number of spiral ridges, that is, the number of the convex portions 2a in the axial direction of the joint main body 3 is “5” as an example of “4 to 6”. Is set to “4 to 6”, even if the position of the end portions 6A, 8A is deviated to either one as shown in FIGS. And securing the tensile strength. FIG. 5 shows a state before the water-stopping layer 4 absorbs water and at the time of drying, and FIG. 6 shows a state of the water-stopping layer 4 when the water-stopping layer 4 has expanded by absorbing water.
[0025]
7 and 8 show a case where the number of spiral ridges, that is, the protrusions 2a in the axial direction of the joint body 3 is set to "2.5" as an example of "2 or more". When the end portions 6A and 8A are positioned at the center or substantially the center in the axial direction of the joint main body 3 when the mounting member 1 is mounted, it is possible to achieve both appropriate securing of liquid tightness and securing of tensile strength, and furthermore, screw-in. The amount and the amount of unscrewing are minimized, and connection operability is improved. 7 shows a state before water absorption of the water stopping layer 4 and at the time of drying, and FIG. 8 shows a state at the time of water stopping when the water stopping layer 4 has expanded by absorbing water.
[0026]
9 and 10 show a case where the number of spiral ridges, that is, the convex portions 2a in the axial direction of the joint main body 3 is set to "8" as an example of "7 to 8". Even when the positions of the end portions 6A and 8A are shifted to one side as shown in the figure at the time of mounting, it is possible to achieve both the securing of appropriate liquid tightness and the securing of tensile strength, and FIGS. Compared with the embodiment of FIG. 8, the tensile strength can be further improved. 9 shows a state before the water-blocking layer 4 absorbs water and at the time of drying, and FIG. 10 shows a state at the time of water-blocking where the water-blocking layer 4 has expanded by absorbing water.
[0027]
In short, if the number of the protrusions 2a is less than “2”, no tensile strength is obtained, and if the number of the protrusions 2a exceeds “8”, the screw-in amount and the screw-back amount are excessive. Due to this, the workability at the time of connection deteriorates, and particularly when the pipe 6 or 8 has a bend, it becomes difficult to connect. Therefore, the number of the above-mentioned protrusions 2a is shown in FIGS. By setting the value in the range of "2 to 8", desirably in the range of "2.5 to 7.5", it is configured to achieve both securing of tensile strength and improvement of workability. .
[0028]
FIG. 11 is a partially enlarged cross-sectional view of the water-stopping layer 4 before water absorption and at the time of drying (at the time of releasing moisture). The inner diameter is D1, and the outer diameter of the ridge 5a of the spiral uneven strip 5 of the tube 6 (only one tube 6 is shown in FIG. 11 for convenience of illustration, but the other tube 8 is also the same) is D2, When D1 / D2 = α, this value α is less than 1.0, preferably set to 0.75 <α <1, more preferably set to 0.80 <α <0.90, and more preferably set to 0. 82 <α <0.88.
[0029]
In other words, when α = 1, there is no catch when the pipes 6, 8 are connected by the pipe joint 1, and the tensile strength cannot be secured. When α = 0.75 or less, the dimensions of the pipes 6, 8 In this case, if the manufacturing variation occurs, the connectivity deteriorates. Therefore, by setting 0.75 <α <1, the appropriate tensile strength is secured while facilitating the connectivity.
[0030]
When 0.80 <α <0.90, a sufficient tensile strength can be ensured while improving the connectivity. When 0.82 <α <0.88, the connectivity is improved. The improvement of the tensile strength can be ensured while further improving.
[0031]
In addition, as shown in FIG. 11, the joint body 3 is integrally formed with the spiral uneven strip 2 screwed to the spiral uneven strips 5, 7 of the pipes 6, 8, and as shown in FIG. When the pipes 6 and 8 are connected, the inner end of the convex portion 2a of the spiral ridge inwardly in the radial direction of the joint main body 3 (however, in this case, the inside of the convex portion 2a in a state not including the water blocking layer 4) (End) and the outer ends of the adjacent ridges 5a, 7a of the spiral ridges 5, 7 of the tubular bodies 6, 8 are overlapped by a predetermined amount W in the radial direction.
[0032]
The amount of overlap W can be set to an arbitrary value corresponding to the outer diameter D2 of the pipes 6 and 8, and a sufficient tensile strength (pull-out strength) of the pipe joint 1 can be secured by this overlap structure. Can be.
[0033]
FIG. 12 is a cross-sectional view taken along line XX of FIG. 3, and at least one projection 9 for connection operation (having an opening angle of 180 degrees in the drawing, (Showing a total of two ridges integrally formed over the entire length in the axial direction).
[0034]
The protrusions 9, 9 prevent the worker's hand from slipping at the time of attachment for connecting the pipes 6, 8 with the pipe joint 1, or at the time of removing the pipe joint 1 from the pipes 6, 8 for removal. In this way, the fitting and removal operations of the pipe joint 1 are facilitated. Further, as shown in FIG. 1, the projections 9, 9 are integrally formed along the outer surfaces of the projections 2a and the recesses 2b in the spiral ridges 2 of the joint body 3, so that the projections 2a are particularly deformed. This is prevented by the part 9 and, as a result, the tensile strength is further improved.
[0035]
13 and 14 are enlarged views showing the detailed structure of the water blocking layer 4. First, about 10 to 25 wt% of a base fiber 10 made of a resin such as PET which is a base material of a nonwoven fabric, and a high melting point water swelling. A water-expandable fiber 11 in which a resin material is fibrillated (a fiber that expands when absorbing water and releases moisture when the surrounding humidity is low), about 70 to 90 wt%, and a binder 12 such as low melting point PET (specifically, a binder resin) Using about 2 to 15 wt%, these are mixed almost evenly to form a nonwoven fabric (nonwoven fabric forming step).
[0036]
Here, as the above-mentioned water-swelling fiber 11, a softening point is a product of Bel Oasis (registered trademark, Kanebo Synthetic Fibers Co., Ltd.) having a softening point of about 170 ° C., and a polymer having sodium polyacrylate as a main component is directly spun, (Highly water-absorbing and highly moisture-absorbing fibers formed into fibers). Further, a binder having a low melting point of about 120 ° C. is used as the binder 12.
[0037]
Next, the flat non-woven fabric is formed into a cylindrical shape, and the cylindrical non-woven fabric is applied to an inner mold (more specifically, an inner mold having a plurality of divided structures and a shape surface forming a spiral uneven strip). An outer mold having a half-split structure (specifically, an outer mold having a shape surface forming a spiral uneven strip) is arranged, and a joint body 3 is formed between the inner surface of the outer mold and the outer peripheral surface of the nonwoven fabric. Is filled with a synthetic resin or synthetic rubber, and the outer mold is closed, heated and pressed at a molding temperature of about 150 to 180 ° C., and the binder 12 is melted by the heat at the time of this processing, as shown in FIG. The base fiber 10 and the water-swelling fiber 11 are firmly bonded by the binder 12 that has been melted into the water (the bonding step by the binder), and the water-stop layer 4 is integrated with the joint body 3 (the integration step). ), The pipe joint 1 shown in FIG. 1 is obtained after the mold is separated.
[0038]
The water-swelling fibers 11 in the water-stopping layer 4 expand radially when water is absorbed to be in the state shown in FIG. 14 and exhibit a water-stopping effect. The water-swellable fibers 11 can be prevented from falling off the nonwoven fabric base material both before and after water absorption.
[0039]
In addition, instead of the above-described water-expandable fiber 11 in which the high-melting-point water-expandable resin material is fiberized, a water-expandable fiber in which the low-melting-point water-expandable resin material is fiberized (for example, Lanseal having a softening point of about 120 ° C. If a trademark (Toyobo Co., Ltd. product) is used, no binder is required, and the water-expandable fiber itself functions as a binder. That is, the water-expandable fibers are melted by the heat during processing and are firmly bonded to the base fibers 10.
[0040]
Alternatively, the water-blocking layer 4 may be formed using a non-woven fabric impregnated with a liquid water-absorbing resin (for example, Equos (trademark), manufactured by Sunadd Co., Ltd.). In any case, since the water-swelling fiber or the water-absorbent resin hardly falls off from the base fiber 10, when the water-stopping layer 4 releases water and returns to the original state, the pipe joint 1 used once is removed. Once removed, the pipe joint 1 can be used again, and as a result, reuse (repeated use) of the pipe joint 1 can be achieved.
[0041]
In the embodiment shown in FIGS. 1 to 14, the joint body 3 is made of synthetic resin. However, the joint body 3 may be made of synthetic rubber as shown in FIG. 15, or as shown in FIG. The outer peripheral portion 3 may be configured to have an outer peripheral flat shape having no groove portion.
[0042]
As described above, the pipe joint of the above embodiment is the pipe joint 1 including the joint body 3 that connects the ends of the pipe bodies 6 and 8 having the spiral ridges 5 and 7, and the inner periphery of the joint body 3. A waterproof layer 4 is provided on the surface, and when the pipes 6 and 8 are connected by the joint body 3, a substantially uniform clearance C is formed between the outer peripheral surfaces of the pipes 6 and 8 and the waterproof layer 4. It is a thing.
[0043]
The water stopping layer 4 absorbs water and expands to stop water between the pipes 6 and 8 and the joint body 3. Further, the clearance C can be set to an arbitrary value of 0.2 mm to 5.0 mm corresponding to the outer diameter of the tubes 6 and 8.
[0044]
According to this configuration, since the substantially uniform clearance C is formed, attachment and detachment of the joint body 3 becomes easy, connection operability of the joint body 3 is improved, and the pipe body 6 or 8 is bent. In this case, the connection between the pipes 6 and 8 and the pipe joint 1 is facilitated by the clearance C, and the clearance C secures a water passage through which water and moisture can enter actively. 4, a quick water-absorbing expansion allows a reliable water stopping effect to be obtained. Further, the formation of the clearance C can prevent the water-swelling fibers and the water-absorbent resin used in the water-stopping layer 4 from falling off due to mechanical external force, so that the durability of the pipe joint 1 can be improved.
[0045]
In addition, the value α obtained by dividing the inner diameter D1 of the joint body 3 including the water blocking layer 4 by the outer diameter D2 of the ridges of the spiral irregularities of the pipes 6, 8 is set to less than 1.0. .
According to this configuration, since the value α is set to less than 1.0, the pipe bodies 6 and 8 can be reliably connected by the joint body 3.
[0046]
In addition, the joint body 3 is integrally formed with a helical ridge (see spiral ridge 2) which is screwed with the spiral ridges 5 and 7 of the pipes 6 and 8. 8, the ends of the convex portions 2a of the spiral ridges inward in the radial direction of the joint body 3 and the ends of the adjacent ridges 5a, 7a of the spiral ridges 5, 7 of the tubular bodies 6, 8 have the same diameter. In the direction (see the overlap amount W).
[0047]
According to this configuration, the end of the convex portion 2a of the spiral ridge (the end of the convex portion 2a not including the water blocking layer 4) inward in the radial direction of the joint body 3 and the spiral of the pipes 6, 8 are formed. Since the ends of the adjacent ridges 5a, 7a of the ridges 5, 7 overlap in the radial direction, a sufficient tensile strength (pull-out strength) can be secured.
[0048]
Further, a projection 9 for connection operation is provided on the outer peripheral side of the joint body 3.
According to this configuration, the protrusion 9 prevents the operator's hand from slipping during the connection operation, and as a result, the attachment and detachment operation of the pipe joint 1 can be facilitated.
[0049]
In addition, the number of spiral ridges in the axial direction of the joint main body 3 (see the number of the protrusions 2a) is set to 2 to 8.
According to this configuration, it is possible to achieve both the securing of the tensile strength and the improvement of the workability at the time of connection between the pipes 6, 8 and the joint body 3. That is, when the number of the protrusions 2a is less than 2, no tensile strength is obtained, and when the number of the protrusions 2a exceeds 8, the workability at the time of connection deteriorates. Since the connection becomes difficult when there is a bend, the number of the protrusions 2a is set to 2 to 8, preferably 2.5 to 7.5, thereby ensuring the tensile strength and workability. It is possible to achieve both improvement and improvement.
[0050]
In correspondence between the configuration of the present invention and the above-described embodiment,
The spiral ridge of the present invention corresponds to the spiral uneven ridge 2 of the embodiment,
Similarly,
Although the number of spiral ridges corresponds to the number of projections 2a,
The present invention is not limited only to the configuration of the above embodiment.
[0051]
【The invention's effect】
According to the present invention, when the pipe is connected with the joint body, a substantially uniform clearance is formed between the outer peripheral surface of the pipe body and the water blocking layer. The operability is improved, the connection between the pipe body and the pipe joint is easy even when the pipe body has a bend, and the above clearance secures a water passage that allows water and moisture to enter actively, It is an object of the present invention to provide a pipe joint capable of obtaining a reliable water stopping effect by rapid water expansion of a water stopping layer at the time of water absorption.
[Brief description of the drawings]
FIG. 1 is a perspective view of a pipe joint of the present invention.
FIG. 2 is a perspective view of a pipe joint and a pipe body.
FIG. 3 is a sectional view showing a connection state of a pipe body by a pipe joint.
FIG. 4 is a sectional view when water is stopped.
FIG. 5 is a cross-sectional view showing a state in which a tube butting portion is offset to one side.
FIG. 6 is a cross-sectional view of the structure of FIG. 5 when water is stopped.
FIG. 7 is a sectional view showing another embodiment of the pipe joint.
FIG. 8 is a cross-sectional view of the structure of FIG. 7 when water is stopped.
FIG. 9 is a sectional view showing still another embodiment of the pipe joint.
FIG. 10 is a cross-sectional view of the structure of FIG. 9 when water is stopped.
FIG. 11 is an enlarged sectional view showing a dimensional relationship between a pipe joint and a pipe body.
FIG. 12 is a sectional view taken along line XX of FIG. 3;
FIG. 13 is an explanatory view showing a state in which the water blocking layer is joined by a binder.
FIG. 14 is an explanatory view at the time of fiber expansion.
FIG. 15 is a partially enlarged sectional view showing still another embodiment of the pipe joint.
FIG. 16 is a partially enlarged sectional view showing still another embodiment of the pipe joint.
[Explanation of symbols]
1: Pipe fitting 2: Spiral irregularities (spiral protrusions)
2a Projection 3 Joint body 4 Waterproof layer 5, 7 Spiral uneven strips 5a, 7a Crests 6, 8 Tube 9 Protrusion C Clearance D1 Inner diameter D2 of joint body Outer diameter

Claims

A pipe joint provided with a joint body that connects the ends of a pipe body having a spiral uneven strip, wherein a water-stop layer is provided on an inner peripheral surface of the joint body,
A pipe joint in which a substantially uniform clearance is formed between the outer peripheral surface of the pipe body and the water blocking layer when the pipe body is connected with the joint body.

2. The pipe joint according to claim 1, wherein a value obtained by dividing an inner diameter of the joint body including the water blocking layer by an outer diameter of a ridge of the spiral concave and convex strip of the pipe is set to less than 1.0. 3.

A spiral ridge is integrally formed on the joint body to be screwed into a spiral ridge of the tube,
When the pipe is connected by the joint body, the convex end of the spiral ridge inwardly in the radial direction of the joint body and the adjacent ridge end of the spiral concavo-convex strip of the tubular body radially overlap with each other. 3. The pipe joint according to 1 or 2.

The pipe joint according to any one of claims 1 to 3, wherein a projection for connection operation is provided on an outer peripheral side of the joint body.

The pipe joint according to any one of claims 1 to 4, wherein the number of spiral ridges in the axial direction of the joint body is set to 2 to 8.