JP3995459B2

JP3995459B2 - Method and apparatus for manufacturing synthetic resin core for supporting elastic shrinkable tube

Info

Publication number: JP3995459B2
Application number: JP2001376637A
Authority: JP
Inventors: 昭夫永吉; 清治永吉
Original assignee: ユーシー産業株式会社
Priority date: 2001-12-11
Filing date: 2001-12-11
Publication date: 2007-10-24
Anticipated expiration: 2021-12-11
Also published as: JP2003180014A

Description

【０００１】
【発明の属する技術分野】
本発明は、電気ケーブル同士の接続部を弾性収縮チューブの弾性収縮力によって被着させる際に、この弾性収縮チューブを外径方向に拡張させた状態に支持する円筒形状の合成樹脂製コアーの製造方法及び装置に関するものである。
【０００２】
【従来の技術】
電気ケーブルの直線接続部を弾性収縮チューブによってシールする際に、弾性収縮チューブは電気ケーブルよりも小径であるため、まず、該弾性収縮チューブを電気ケーブルよりも大径の円筒形状のコアーの外周面に被せて拡張させた状態に保持し、コアー内に電気ケーブルの直線接続部を配設したのち、コアーを除去することによって弾性収縮チューブを電気ケーブルの直線接続部に圧着、被覆させて防水、防塵保護することが行われている。
【０００３】
弾性収縮チューブを拡張状態に保持する上記のような円筒形状のコアーとしては、従来から、ポリプロピレンやポリエチレン等の合成樹脂製紐状体を螺旋巻して隣接するリング状の紐状体部分の接合部における外周面を螺旋方向に一定間隔毎に溶着してなる構造のものや、内周面に全長に亘って複数条の突条を設けてなる合成樹脂製筒状体を押出成形によって製造し、この筒状体の外周面から内周面の突条に達する深さでもって螺旋状に切り込むことにより、隣接するリング状の紐状部分が上記突条によってのみ、連結してなる円筒形状のコアー等が知られている。
【０００４】
そして、いずれのコアーにおいても、一端側の紐状部分を引っ張ることによって前者においては溶着部を、後者においては突条部を分断させながらリング状紐状部分を順次引き出して除去し、コアーの外周面に拡張状態で支持されている弾性収縮チューブをその紐状部分の除去によって弾性収縮させてコアーに挿入している電気ケーブルの接続部を圧着、シールするように構成している。
【０００５】
【発明が解決しようとする課題】
しかしながら、前者のコアーにおいては、外周面に溶着による突起が形成されているため、薄肉の弾性収縮チューブをその外周面に圧着させて拡張状態で支持した場合、突起によって弾性収縮チューブが破れたり、小孔があけられて防水、防塵処理が不十分となる問題点がある。このような弾性収縮チューブの破損等はコアーを除去する際においても、溶着による突起が弾性収縮チューブの内面に引っ掛かって生じることになる。
【０００６】
一方、後者のコアーにおいては、リング状の紐状体部分同士を連結している突条部が内周面に設けられているため上記のような問題点が生じないが、押出成形によって得られた筒状体を螺旋状に切り込む際に、その切り込み深さが浅いと、隣接するリング条の紐条体部分を連結している突条部の厚みが厚くなってリング条の紐条体部分を互い分離させることが困難となり、従って、突条部に対する切り込み深さの設定が極めて難しいという問題点がある。その上、隣接するリング条の紐条体部分を分離させる時に、突条部が延びて容易に分離させることができず、電気ケーブルの直線接続部を弾性収縮チューブによってシールする作業が円滑に行えず、作業能率が低下するという問題点があった。
【０００７】
上記のような問題点は、前者のコアーにおいてその内周面に隣接するリング条の紐条体部分を連結する溶着部を設ければ解消することができるが、合成樹脂製紐状体を互いに分離可能に結合させながら螺旋巻きし、且つ、その内周側で溶着することが困難であった。
【０００８】
このため、本願出願人等は、特願2000-255603 に記載した構造を有する合成樹脂製コアーを開発した。即ち、このコアーは、図15に示すように合成樹脂製の紐状体51を先に円形リング状に湾曲した紐状体部分51a とこの紐状体部分51a に後続して円形リング状に湾曲した紐状部分51a との対向端面を接合させた状態で中空マンドレル（図示せず）の内周面に接して連続螺旋巻きすることにより円筒形状に形成されていると共に、隣接する円形リング状の紐状部分51a 、51a の接合部分における内周面を中空マンドレルの一端部内に配設した加熱回転輪61の外周面に突設している複数個の突起62によって螺旋方向に一定間隔毎に溶着52した構造としている。
【０００９】
この合成樹脂製コアーによれば、製造時に円形リング状の紐状体部分51a 、51a の対向端面の接合部内周面を加熱回転輪61によって容易に溶着させることができるが、溶着時に加熱回転輪61の突起62が紐状体部分51a 、51a の接合部の内周面に押圧すると、その接合部に突起62の断面形状に応じた矩形状の溶着部52が形成されると共に、この溶着部52の四方の樹脂部が盛り上がって、紐状体部分同士の接合端面に平行な肉盛り部52a と接合端面に直交する肉盛り部52b が形成されることになる。
【００１０】
従って、使用時に溶着部52を断続的に分断させながらコアーの円形リング状紐状体部分51a を順次、解きほぐしていく際に、紐状体部分同士の接合端面に直交する上記肉盛り部52b に達するとこの肉盛り部52b が分断に対して抵抗するために一定の引張力でもって円滑な解きほぐしが行えなくなるばかりでなく、該肉盛り部52b を分断させる際の瞬間的な強い引張力によってその一部が分断面から樹脂粉粒体として欠落し、弾性収縮チューブの内面に付着してこの弾性収縮チューブを損傷させる虞れがあった。
【００１１】
本発明は上記のような問題点に鑑みてなされたもので、その目的とするところは、弾性収縮チューブを損傷させることなく一定の小さな引張力でもって円滑且つ連続的に解きほぐして電気ケーブルに被着させることができる合成樹脂製コアーを能率よく且つ正確に製造することができる方法、及び、その方法の実施に使用する装置を提供するにある。
【００１２】
【課題を解決するための手段】
上記目的を達成するために、請求項１に係る発明は、合成樹脂製コアーの製造方法であって、合成樹脂製の紐状体を中空マンドレル内に供給してこの中空マンドレルの内周面に摺接させながら螺旋方向に円形リング状に湾曲させると共に先に円形リング状に湾曲した紐状体部分と次に円形リング状に湾曲する紐状体部分との対向端面を互いに接合させたのち、中空マンドレル内に配設している溶着具によって互いに接合した対向部分における内周面を接合端面に沿って連続螺旋状に溶着することにより接合端面間を分断可能に一体化した薄肉溶着部を形成し、この溶着によって順次長さ方向に一体的に連結した円形リング状紐状体部分からなる円筒形状のコアー部分を上記中空マンドレル内に配設した回転駆動手段によって螺旋方向に回転させながら中空マンドレルから長さ方向に送り出すことを特徴とする。
【００１３】
また、請求項２に係る発明は、上記合成樹脂製コアーの製造方法を実施するための装置であって、一端部に合成樹脂製紐状体を導入させる導入口を有し且つ導入した該紐状体を円形状の一端部内周面に接して円形リング状に湾曲させると共に湾曲した紐状体部分の一端面を押接させて先に円形リング状に湾曲した紐状体部分に接合させながら他端側に向かって螺旋方向に押し進める垂直な螺旋状押圧端面を設けている中空マンドレルと、この中空マンドレルの一端部内に配設されて上記先に円形リング状に湾曲した紐状体部分と次に円形リング状に湾曲した紐状体部分との接合部の内周面を螺旋方向に連続的に溶着して対向端面間が分断可能な薄肉溶着部を形成する溶着具と、この溶着によって順次螺旋巻き状に一体的に連結した円形リング状紐状体部分よりなる円筒形状のコアー部分を中空マンドレルの内周面に沿って他端側に向かって螺旋状に回転させながら移動させる回転駆動手段とから構成している。
【００１４】
この合成樹脂製コアーの製造装置において、請求項３に係る発明は、上記溶着具を、円形リング状に湾曲した紐状体部分の接合部における内周面に接して回転する加熱回転輪の外周面に上記接合部の内周面を連続螺旋状に溶着する円形外周縁部を設けた構造としていることを特徴とする。
【００１５】
さらに、請求項４に係る発明は、上記回転駆動手段を、それぞれの軸心回りに同一方向に同一速度でもって自転する複数本の可撓性を有する回転索条体から構成していると共に、これらの回転索条体の一端部を、中空マンドレルの内周面に周方向に一定間隔毎に凹設され且つ一端から他端に向かって螺旋方向に傾斜している溝内にそれぞれ配設して、溝内から突出している一部の外周面を円筒形状のコアー部分の外周面に摺接させてコアー部分を回転させるように構成している。
【００１６】
【作用】
弾性収縮チューブを拡張させた状態に保持する合成樹脂製コアーは、合成樹脂製の紐状体を円形リング状に湾曲させながら螺旋巻きして円筒形状に形成され、且つ、隣接する円形リング状の紐状体部分は内周面側において接合部分を薄肉溶着部によって溶着されているから、外周面には溶着による突起が形成されておらず、従って、弾性収縮チューブを破損や損傷させる虞れはない。
【００１７】
このコアー内に電気ケーブルの直線接続部を挿入し、コアーの円形リング状紐状体部分を端部側から解いていくと、円形リング状の紐状体部分の接合部間を連結している溶着部は薄肉であって螺旋方向に連続して設けられているため、溶着部を小さな一定の引張力で引張るだけで軽快に且つ部分的な欠損などを生じさせることなく全長に亘って連続的に分断させることができる。紐状体部分を除去していくと、弾性収縮チューブはその端部側から収縮して電気ケーブルに圧着し、コアーが完全に解体、除去されると、電気ケーブルの接続部における外周面に全面的に圧着してシールした状態となる。
【００１８】
なお、上記コアーの除去作業は、予め、弾性収縮チューブの他端側から露出しているコアーの他端部の円形リング状紐状体部分を解いてコアーの内部を通じて一端側に引き出しておき、この引き出した紐状体部分を引っ張って、他端側の円形リング状紐状体部分を順次、互いに固着している溶着部をその引張力によって分断しながら解いていくものである。
【００１９】
上記コアーとして、隣接する円形リング状の紐状体部分における接合端面同士を上向き係止突条と下向き係止突条とで係止させた構造としておくことにより、コアーを形成している円形リング状の紐状体部分がコアーの長さ方向及び周方向に同一形状でもって順次正確に連結し、隣接する円形リング状紐状体部分の外周面が面一状態に連続して、全長に亘って均一な支持力を発揮し、且つ、弾性収縮チューブを全面的に均一な圧着力でもって圧着させることができる。
【００２０】
さらに、コアーを構成している円形リング状紐状体部分を解いていく場合、先に解かれる円形リング状紐状体部分の一端面側に上向き係止突条を配し、この上向き係止突条に次に解かれる下向き係止突条を係合させた状態にしておくことによって、円形リング条紐状部分を順次コアー内に向かって引き込むと、上向き係止突条が下向き係止突条から容易に且つ自動的に外れながらコアーが円滑に解体される。
【００２１】
このような弾性収縮チューブの支持用合成樹脂製コアーを得るには、請求項１、２に記載したように、中空マンドレルの一端部において、該中空マンドレルの接線方向に開口している導入口に合成樹脂製紐状体を送給すると、この紐状体の互いに平行な両端面（長さ方向の側端面）のうち、中空マンドレルの一端部側に面した端面が、中空マンドレルの一端部に配設した螺旋状に傾斜している垂直な押圧端面に接して他端側に向かって螺旋巻き方向に押し進められながら中空マンドレルの円形状に形成されている一端部内周面によって円形リング状に湾曲させられ、上記螺旋状に傾斜した垂直な押圧端面に沿って一周した時に紐状体の幅に相当するピッチだけ他端側に向かって螺旋状に移動すると共に、その他端面（長さ方向の他側端面）が先に螺旋方向に円形リング状に形成された紐状体部分の一端面に接合する。
【００２２】
この時、紐状体の一端面側に上向き係止突条を、他端面側に下向き係止突条を設けておくことによって先に螺旋状に一回りした紐状体部分の上向き係止突条に次に導入される紐状体部分の下向き係止突条が係合し、隣接する円形リング状紐状体部分がこれらの上下係止突条によって螺旋方向に連続的に連結して内外周面がそれぞれ長さ方向に面一状に連接したコアーを形成していく。さらに、隣接する円形リング状紐状体部分の接合部における内周面が中空マンドレルの一端部内に配設している溶着具によって一定幅でもって螺旋方向に連続的に溶着され、隣接する円形リング状紐状体部分同士を一体に連結した螺旋帯状の薄肉溶着部が形成される。
【００２３】
中空マンドレルの一端部内での上記円形リング状紐状体の形成は、導入口から合成樹脂製紐状体を送り込んでその長さ方向の押し込み力により中空マンドレルの一端部内周面に接して円形状に湾曲させられると共に、上記螺旋状に傾斜した垂直な押圧端面によって他端部側に押し進められる。そして、上記溶着によって順次長さ方向に一体的に連結した円形リング状紐状体部分よりなる円筒形状のコアー部分は、中空マンドレル内に配設した回転駆動手段によって螺旋方向に回転させながら中空マンドレルから長さ方向に送り出されて長尺のコアーを形成していくものである。なお、上記回転駆動手段としては、中空マンドレル内で形成されるコアー部分の外周面複数個所に接して回転する複数本の回転索条体を使用することができる。
【００２４】
【発明の実施の形態】
次に、本発明の具体的な実施の形態を図面について説明すると、図１、図２において、合成樹脂製コアーＡは、ポリプロピレン、ポリエチレン又はポリ塩化ビニルのような比較的硬質で適度な強度を有し、且つ可撓性を有する合成樹脂製の紐状体１を連続螺旋状に湾曲成形することによって所定の内径と外径に形成された一定厚みを有する円筒形状に形成されている。
【００２５】
詳しくは、紐状体１を一定長さ毎に、螺旋方向に円形リング状に湾曲した紐状体部分1aに形成してこの円形リング状紐状体部分1aを順次、隣接する紐状体部分1a、1aの対向端面を分離可能に接合、連結してなる構造を有し、且つ、その接合部分における内周面に紐状体部分1a、1a同士の接合端面を中央にして小幅で一定幅の薄肉溶着部２が接合部に沿って同一螺旋方向に連続的に形成されていて、この薄肉溶着部２の幅方向の中央部、即ち、円形リング状の紐状体部分1a、1aの接合端面の内周側隅角部間を一体化させた極細紐状の薄肉溶着部分2aによって円形リング状の紐状体部分1aがコアー１の端部側から解きほぐされるのを防止してコアー１が円筒形状を維持するように構成している。図中、2b、2bは薄肉溶着部２の形成時に、合成樹脂の溶融によって該薄肉溶着部２の両側に盛り上がった樹脂の突条部で、円形リング状の紐状体部分1a、1a同士の接合端面の内面両側に互いに平行にして連続螺旋状に形成されてあり、これらの突条部2a、2a間に上記薄肉溶着部２が連続螺旋状に形成されている。
【００２６】
この合成樹脂製コアーＡの長さは図１、図３に示すように、弾性収縮チューブＢよりも長く形成されてあり、その外周面に弾性収縮チューブＢを外径方向に拡張させて支持した形態においては、コアーＡの両端部が弾性収縮チューブＢの両端から外部に突出している。さらに、弾性収縮チューブＢを完全に収縮した時の該弾性収縮チューブＢの内径は被覆すべき電気ケーブルＣの外径よりも小径となり、電気ケーブルＣの接続部C1の外周面をその収縮力によって圧着するように形成している一方、上記合成樹脂製コアーＡの内径は電気ケーブルＣの外径よりも充分に大きく、この合成樹脂製コアーＡの内周面と電気ケーブルＣの外周面間に比較的広い空隙部Ｄが形成されるように構成している。
【００２７】
コアーＡを構成している上記合成樹脂製紐状体１は、図２に示すように断面が偏平な横長矩形状に形成されてあり、その長さ方向に沿った互いに平行な両端面（両側端面）において、一端面の下半部に断面Ｌ字状の上向き係止突条３が全長に亘って連続的に突設してあり、他端面の上半部に断面逆Ｌ字状の下向き係止突条４が同じく全長に亘って連続的に突設している。詳しくは、上向き係止突条３は紐状体１の下半部から紐状体１の幅を延長する方向に一定幅、突出している水平突片部3aと、この水平突片部3aの突出端から上方に向かって突設している一定高さの垂直突片部3bとからなり、この垂直突片部3bと紐状体１の一端面との間に上向きに開口した小幅の係止溝3cを形成している。
【００２８】
同様に、下向き係止突条４は紐状体１の他端面における上半部から紐状体１の幅を延長する方向に一定幅、突出している水平突片部4aと、この水平突片部4aの突出端から下方に向かって突設している一定高さの垂直突片部4bとからなり、この垂直突片部4bと紐状体１の他端面との間に下向きに開口した小幅の係止溝4cを形成している。
【００２９】
そして、コアーＡを構成する上記螺旋状に湾曲した隣接する円形リング状の紐状体部分1a、1aの対向端面における接合部は、一方の円形リング状紐状体部分1aに突設している上向き係止突条３に他方の円形リング状紐状体部分1aに突設している下向き係止突条４を係合させることによって互いに連結してあり、この連結によってコアーＡは形崩れすることがなく且つ薄肉溶着部２を引っ張りや径方向の圧潰力によって不測に分断させることのない円筒形状の形態を保持しているものである。なお、紐状体１を円形リング状の紐状体部分1aに湾曲させた状態においては、上記上向き係止突条３は外向き係止突条となり、下向き係止突条４は内向き係止突条となっており、外向き係止突条３の垂直突片部3bが内向き係止突条４の係止溝4cに内向き係止突条４の垂直突片部4bが外向き係止突条３の係止溝3cに、嵌入、係止している。
【００３０】
次に、このように構成した合成樹脂製コアーＡの使用態様について説明すると、まず、図１に示すようにこのコアーＡの外周面に弾性収縮チューブＢを拡張させた状態で圧着させて該コアーＡにより弾性収縮チューブＢを拡張状態で支持させておく。なお、コアーＡは弾性収縮チューブＢの長さよりも長い寸法を有しており、その両端部を所定長さだけ弾性収縮チューブＢから突出させておく。
【００３１】
この弾性収縮チューブＢに接続すべき一方の電気ケーブルＣを挿通すると共にこの電気ケーブルＣと他方の電気ケーブルＣとの電線被覆層C2、C2の端部の剥離により露出させた導電線同士を接続し、この接続部C1を図３に示すように、コアーＡの中央内部に位置させる。さらに、コアーＡはその一端部側においては、最端側の円形リング状紐状体部分1aの下向き（内向き）係止突条４がこの円形リング状紐状体部分1aと隣接した円形リング状紐状体部分1aの上向き（外向き）係止突条３に係止している一方、他端部側においては、最端側の円形リング状紐状体部分1aの上向き（外向き）係止突条３がこの円形リング状紐状体部分1aと隣接した円形リング状紐状体部分1aの下向き（内向き）係止突条４に係止している状態となっている。
【００３２】
従って、コアーＡの他端部側においては、隣接した円形リング状紐状体部分1a、1aを順次、互いに係合した係止突条３、４を外しながら且つ薄肉溶着部２を順次分断させながらコアーＡの中空内部に向かって解きほぐすことができができる構造となっており、この他端部における円形リング状紐状体部分1aを予め、数リング分だけ解いてコアーＡの中空内を一端側に直線状に引き込み、その先端部をコアーＡの一端から外部に突出させた状態にしている。
【００３３】
この状態にしてコアーＡの中空内を通じて外部に突出した上記紐状体部分の先端部を引っ張ると、図４に示すように、コアーＡの他端部側から円形リング状紐状体部分1aが、順次、その上向き（外向き）係止突条３を次の円形リング状紐状体部分1aの下向き（内向き）係止突条４から離脱させながら且つ薄肉溶着部２を剪断状態に分断させながら順次、解きほぐされ、コアーＡの他端側に引き出される。この際、薄肉溶着部２は紐状体部分1a、1a間の接合部の内周面を薄い一定の厚みでもって接合部の全長に亘って螺旋方向に連続し且つその幅方向の中央部の極細紐状の薄肉溶着部分2aによって円形リング状紐状体部分1a、1a間を一体に連結しているため、紐状体部分1aの先端部を小さな一定の引張力でもって引っ張ることにより、薄肉溶着部２の極細紐状の薄肉溶着部分2aを全長に亘って容易に且つ均一に分断させることができる。
【００３４】
こうして、コアーＡがその他端から一端に向かって円形リング状紐状体部分1aを順次、解かれると、コアーＡに支持されていた弾性収縮チューブＢが円形リング状紐状体部分1aの解除に従ってその弾性収縮力により、まず、図４に示すようにその他端部を他方の電気ケーブルＣの絶縁被覆層C2上に圧着させたのち、中央部をケーブル同士の接続部C1上に圧着させ、コアーＡが完全に撤去された時に一端部に至る全長を図５に示すように一方の電気ケーブルＣの絶縁被覆層C2上にまで圧着させて電気ケーブルＣ、Ｃの接続部C1を防水、防塵状態にシールするものである。
【００３５】
次に、上記合成樹脂製コアーＡの製造装置とその製造方法について説明する。製造装置は図６〜図９に示すように、一端部に上記合成樹脂紐状体１を導入させる導入口13（図９に示す）を有し、且つ、導入した該紐状体１を一端部内周面で円形リング状に湾曲させると共に湾曲した紐状体部分1aの一端面（一側端面）を他端側に向かって押圧して先行する円形リング状紐状体部分1aと後続する円形リング状紐状体部分1aとの対向端面（対向側端面）を互いに接合させながら他端側に向かって螺旋方向に押し進める垂直な螺旋状押圧端面12a を有するリング部材11を備えた中空マンドレル10と、この中空マンドレル10の一端部内に配設されて上記先に円形リング状に湾曲した紐状体部分1aと次に円形リング状に湾曲した紐状体部分1aと接合部の内周面を連続螺旋状に溶着する溶着具20（図７に示す）と、この溶着具20による溶着２によって順次螺旋方向に一体的に連結した円形リング状紐状体部分よりなる円筒形状のコアー部分を中空マンドレル10の内周面に沿って他端側に向かって螺旋状に回転させながら移動させる回転駆動手段30とから構成している。
【００３６】
中空マンドレル10の一端部に設けている上記リング部材11は、その内径を中空マンドレル10の内径よりも僅かに小径に形成し且つ中空マンドレル10と同一中心線上に配して該中空マンドレル10の一端面にその対向端面を当接させた状態で固着している外側リング部材11A と、この外側リング部材11A の一端部内周面に嵌着させている内側リング部材11B とからなる。
【００３７】
この内側リング部材11B は、外側リング部材11A の一端面に当接させた状態で固着したフランジ部11b1に外側リング部材11A の一端部内に挿嵌したリング部11b2を突設してなり、このリング部11b2の外周面を紐状体１の厚みに相当する深さでもって断面Ｌ字状に切り欠くと共にその切欠によって形成された垂直な一端面を、後述する導入口13から導入された紐状体１が上周端から湾曲しながら一周する間に該紐状体１の幅に相当する距離だけこの円形状に湾曲した紐状体部分1aを他端側に押し進めるように螺旋状に傾斜した押圧端面12a に形成している。
【００３８】
さらに、断面Ｌ字状に切欠かれた上記内側リング部材11B のリング部11の外周面と外側リング部材11A の内周面とで該外側リング部材11A の他端側に向かって開口した円環状空間部12を形成していると共に内側リング部材11B の上周部にリング部11b2の外周面に対して外側方から接線方向に円環状空間部12の上端部に連通した紐状体１の導入口13を形成してあり、この導入口13の一端側の垂直な壁を上記螺旋状に傾斜した垂直な押圧端面12a の上周端に連設させている。そして、このリング部材11を備えている上記中空マンドレル10は機台５上に水平状態にして設置、固定されている。
【００３９】
一方、円筒形状の中空マンドレル10の内周面には図12に示すように、周方向に一定間隔毎に該中空マンドレル10の一端から他端に向かって僅かに螺旋方向に傾斜している断面Ｃ字状の傾斜溝14、14・・・が凹設されている。この傾斜溝14の中空マンドレル10の軸心方向に対する周方向の傾斜角度は、中空マンドレル10の軸心方向に対する上記螺旋状に傾斜した垂直な押圧端面12a の傾斜角度に等しく形成されている。即ち、この押圧端面12a に対して各傾斜溝14が直角方向に向けられている。
【００４０】
なお、中空マンドレル10を１本の円筒体より形成しておいてもよいが、その内周面に上記のように一端から他端に向かって螺旋方向に傾斜した傾斜溝 14を穿設することは技術的に困難であるため、図11、図12に示すように、一定厚みの円環状部材10A にこの部材の内周面に一部を開口させた断面Ｃ字状の孔14a を周方向に一定間隔毎に且つ円環状部材10A の前後両端面に亘って中空マンドレル10の軸心方向に平行に設け、この円環状部材10A を複数枚、直列状に重ね合わせ且つ順次、周方向に僅かにずらした状態で一体に固定することにより、一連の孔14a で上記傾斜溝14を形成している。
【００４１】
そして、各傾斜溝14内には金属線をコイル状に巻回することによって形成された可撓性を有する索条体31の一端部をその周面の一部が傾斜溝14から中空マンドレル10内に突出させた状態にして傾斜溝14内で回転可能に配設している。なお、傾斜溝14から突出している上記索条体31の一部の突出寸法は、中空マンドレル10の内周面からこの内周面よりも僅かに小径の上記外側リング部材11A の内周面に達する寸法であり、従って、外側リング部材11A の内周面に沿って中空マンドレル10側に送り出される円形リング状紐状体部分1aの外周面に上記索条体31の突出部の外周面を摺接させて一連に連続した円形リング状紐状体部分1aからなるコアー部分を螺旋方向に回転させながら中空マンドレル10の他端に向かって移動させるように構成している。
【００４２】
各索条体31は図７に示すように、中空マンドレル10から引き出されて外方に拡げられ、中空マンドレル10と対向して機台５上に設置している索条体回転駆動機構40によって同一方向に一斉に回転駆動させられるように構成している。この索条体回転駆動機構40は、各索条体31の端部に中心部を固着させた歯車をモータ駆動により噛合歯車を介して同時に同一方向に回転させる公知の手段を採用している。
【００４３】
また、中空マンドレル10の一端部内に配設されている溶着具20は図11、図12に示すように外周面に小幅の円形外周縁部21a を突設してなる加熱回転輪21と、この加熱回転輪21を先端部に回転自在に支持している筒軸23と、この筒軸23内を通じて回転輪21を加熱するヒータ（図示せず）とからなり、加熱回転輪21の回転方向を中空マンドレル10の上記リング部材11に設けているガイド溝12によって成形された互いに接合する円形リング状紐状体部分1a、1aの接合部の螺旋移動方向に向け且つその円形外周縁部21a を接合部の内周面に摺接させて円形リング状紐状体部分1aの螺旋方向への回転による摩擦力で加熱回転輪21を回転させながら、先行する円形リング状紐状体部分1aと後続する円形リング状紐状体部分1aとの接合部の内周面を連続的に該接合部の長さ方向に溶着２するように構成している。
【００４４】
６は中空マンドレル10のリング部材11の外側方において、機台５上に設置された紐状体供給装置で、上下一対のロール6a、6bによって紐状体１を挟みながらその回転力によって紐状体１をリング部材11の上記導入口内に連続的に且つ強制的に送り込むものであり、その送り込み力によって紐状体１を上述したように外側リング部材11A の内周面に接して湾曲させると共に湾曲した円形リング状紐状体部分1aを内側リング部材11B の上記螺旋状に傾斜した垂直な押圧端面12a によって回転駆動手段30側（他端側）に向かって押し進めるようにしている。
【００４５】
このように構成した製造装置によって上記コアーＡを製造するには、供給装置６から導入口13内に上記断面横長矩形状の合成樹脂製紐状体１を供給すると、該紐状体１は上向き係止突条３を突設している一端面（一側端面）を導入口13の一側壁に摺接させながらこの一側壁に連続しているリング部材11内の円環状空間部12の一端部における上記螺旋状に傾斜した垂直な押圧端面12a の傾斜始端部（上端部）に接して円環状空間部12内に送り込まれ、その送り込み力によって外側リング部材11A の内周面に接して円形リング状に湾曲させられる。
【００４６】
この時、紐状体１が上記螺旋状に傾斜した垂直な押圧端面12a によって円環状空間部12内を外側リング部材11A の他端側に押し進められ、この状態で上記押圧端面12a を一回りすることによって円形リング状に形成された紐状体部分1aが押圧端面 12a から紐状体１の幅に略等しい距離を存した他端側の上周端に達した時に、その一端面から突設している上向き係止突条３が上記導入通路13を通じて連続して供給されてくる紐状体１の他端面に突設している下向き係止突条４に係合させることになる。
【００４７】
こうして、先行する円形リング状紐状体部分1aに後続する円形リング状紐状体部分1aとが互いに係止突条３、４によって係合、連結したのち、これらの円形リング状紐状体部分1a、1aの接合部の内周面は、該内周面との摺接力によって回転する加熱回転輪21の円形外周縁部21a によって該接合部に沿った螺旋方向に連続的に溶着される。
【００４８】
具体的には、加熱回転枠21の円形外周縁部21a の外周面が互いに接合した円形リング状紐状体部分1a、1aの接合部の内周面にその幅方向の中央部を位置させた状態で押接して該接合部に円形外周縁部21a の幅に等しい幅の薄肉溶着部２を連続的に形成される。この際、円形リング状の紐状体部分1a、1aの接合端面においては、その互いに対向した内周側隅角部が溶融して図２に示すように極細で薄肉の紐状溶着部2aとなり、この紐状溶着部2aによって円形リング状紐状体部分1a、1a同士が分断可能に一体的に接続、連結した構造となる。また、上記薄肉溶着部２の両側方には紐状体部分1a、1aの接合部内周面の溶融によって合成樹脂が盛り上がった互いに平行な突条部2b、2bが接合端面を中央にしてその両側方に連続螺旋状に形成される。
【００４９】
このように、ガイド溝12上に沿って先に円形リング状に湾曲させられた紐状体部分1aと次に供給されている紐状体部分1aとを互いにその係止突条３、４を係合させながら順次、図13に示すように円形リング状に湾曲させられたのち、その接合部の内周面を加熱回転輪21の円形外周縁部21a によって連続螺旋状に溶着２されて紐状体部分1a、1aの接合対向面の内周部が一体的に連結し、この円形リング状紐状体部分1a、1aが次々と螺旋状に連続してコアーＡを形成しながら外側リング部材11A の他端部内周面にその外周面を摺接させて螺旋方向に回転しながら他端側に向かって移動する。
【００５０】
さらに、中空マンドレル10内に導入されたコアー部分は、その外周面に接して回転する複数条の索条体31によって螺旋方向に回転させられながら中空マンドレル10の他端から該中空マンドレル10の延長方向に送り出されて長尺のコアーＡを形成していく。こうして、製造された長尺のコアーＡは所定長さ毎に切断されて弾性収縮チューブＢの支持用合成樹脂製コアーとされるものである。
【００５１】
なお、以上の実施の形態においては、中空マンドレル10内で形成されるコアーＡの回転駆動手段30として該コアーＡの外周面に接して回転する複数条の回転索条体31を採用しているが、中空マンドレル10のリング部材11の一端部側から複数個の回転ローラを挿入してその回転ローラを中空マンドレル10内で形成されるコアーＡの内周面に接して回転させるようにしてもよく、また、隣接する円形リング状紐状体部分1a、1aの接合部内周面を溶着する溶着具20としては、超音波溶接を使用してもよい。
【００５２】
さらに、隣接する円形リング状紐状体部分1a、1a同士の係合構造としては、断面Ｌ字状の上向き係止突条３と、断面逆Ｌ字状の下向き係止突条４とによって形成しているが、図14（イ）に示すように互いに接合する傾斜端面3A、4Aによって形成しておいてもよく、同図（ロ）、（ハ）、（ニ）に示すように、互いに係合する鋸歯状突起、或いは凹凸円弧部を有する傾斜端面3B、4Bに形成しておいてもよい。また、円形リング状紐状体部分1a、1a同士は、上述したようにその接合部の内周面を小間隔毎に溶着２されて円筒形状のコアーＡの形態を維持することができるので、同図（ホ）に示すように、垂直な端面3C、4Cに形成しておいてもよい。
【００５３】
【発明の効果】
以上のように本発明の弾性収縮チューブの支持用合成樹脂コアーの製造方法及び製造装置は、請求項１、２に記載したように、中空マンドレルの一端部に設けている導入口から合成樹脂製紐状体を中空マンドレル内に供給することによって、該紐状体部分を中空マンドレルの内周面に摺接させながら周方向に移動させて正確に円形リング状に湾曲させることができると共に、その紐状体の一端面を中空マンドレルの一端部内に形成している螺旋状に傾斜した垂直な押圧端面に摺接させながら他端側に向かって周方向に移動させるので、この押圧端面に沿って一周した時に紐状体の幅に相当するピッチだけ他端側に向かって螺旋状に移動させられて、次に連続して導入される紐状体部分の他端面を先に一周した紐状体部分の一側面に確実に接合させながら、円筒形状のコアーを精度よく形成することができる。
【００５４】
この時、紐状体の一端面側に上向き係止突条を、他端面側に下向き係止突条を設けておくことによって先に螺旋状に一回りした紐状体部分の上向き係止突条に次に導入される紐状体部分の下向き係止突条が確実に係合し、隣接する円形リング状がこれらの上下係止突条によって一体に連結して内外周面がそれぞれ長さ方向に面一状に連接したコアーを形成することができ、さらに、中空マンドレルの一端部内に溶着具を配設しているので、この溶着具の円形外周縁部によって隣接する円形リング状紐状体部分の接合部における内周面を螺旋方向に連続的に溶着して円形紐状体部分の接合端面の内周部に該接合端面同士を一体化させた極薄の均一な厚みの薄肉溶着部分を正確に形成することができ、内周面側のみで隣接する円形リング状紐状体部分を分離可能に連結してなるコアーを能率よく製造することができる。
【００５５】
その上、円形リング状の紐状体部分が順次連結してなる円筒形状のコアー部分は、中空マンドレル内に配設した回転駆動手段によって螺旋方向に回転させられるので、連続的に製造されるコアーを一定の速度でもって中空マンドレル内から円滑に長さ方向に引き出しながら、長尺のコアーを能率よく製造し得る。
【図面の簡単な説明】
【図１】弾性収縮チューブを被せている合成樹脂製コアーの斜視図、
【図２】合成樹脂製コアーの一部拡大断面図、
【図３】電気ケーブルの接続部を挿入している状態の一部切欠斜視図、
【図４】電気ケーブルの接続部に弾性収縮チューブを被着させている状態の斜視図、
【図５】電気ケーブルの接続部を弾性収縮チューブで被着した状態の斜視図、
【図６】合成樹脂製コアーの製造装置の簡略縦断側面図、
【図７】その一部切欠縦断側面図、
【図８】リング部材の簡略縦断側面図、
【図９】その簡略縦断正面図、
【図１０】装置全体の簡略正面図、
【図１１】円形リング状紐状体部分を形成している状態の縦断側面図、
【図１２】その正面図、
【図１３】その簡略斜視図、
【図１４】円形リング状紐状体部分の係合構造を示す断面図、
【図１５】円形リング状紐状体部分の内周面を断続的に溶着した状態を示す斜視図。
【符号の説明】
Ａ合成樹脂製コアー
Ｂ弾性収縮チューブ
Ｃ電気ケーブル
C1 接続部
１合成樹脂製紐状体
1a 円形リング状紐状体部分
２薄肉溶着部
2a 極細紐状の薄肉溶着部分
３上向き係止突条
４下向き係止突条
10 中空マンドレル
11 リング部材
12 ガイド溝
20 溶着具
22 円形外周縁部
30 回転駆動手段
31 索条体[0001]
BACKGROUND OF THE INVENTION
  The present invention provides a cylindrical synthetic resin core that supports the elastic contraction tube in an expanded state in the outer diameter direction when the connecting portions of the electric cables are attached by the elastic contraction force of the elastic contraction tube.ofThe present invention relates to a manufacturing method and apparatus.
[0002]
[Prior art]
  When sealing a straight connection portion of an electric cable with an elastic contraction tube, since the elastic contraction tube has a smaller diameter than the electric cable, first, the outer periphery of the cylindrical core having a larger diameter than the electric cable is attached to the elastic contraction tube. It is held in an expanded state by covering it, and after arranging the linear connection part of the electric cable in the core, the elastic contraction tube is crimped and covered on the linear connection part of the electric cable by removing the core, waterproofing, Dust protection is carried out.
[0003]
  Conventionally, as a cylindrical core as described above for holding the elastic contraction tube in an expanded state, a synthetic resin string such as polypropylene or polyethylene is spirally wound to join adjacent ring-shaped strings. The outer peripheral surface of the portion is welded at regular intervals in the spiral direction, and the synthetic resin cylindrical body having a plurality of protrusions over the entire length on the inner peripheral surface is manufactured by extrusion molding. The cylindrical ring formed by connecting the adjacent ring-shaped string-like portions only by the above-mentioned ridges by cutting in a spiral shape with a depth reaching the ridges on the inner peripheral surface from the outer peripheral surface of this cylindrical body. Cores are known.
[0004]
  In any core, by pulling the string-like part on one end side, the welded part is removed in the former, and in the latter, the ring-like string-like part is removed while separating the ridges, and the outer periphery of the core is removed. The elastic contraction tube supported in an expanded state on the surface is elastically contracted by removing the string-like portion, and the connection portion of the electric cable inserted into the core is crimped and sealed.
[0005]
[Problems to be solved by the invention]
  However, in the former core, because the projection by welding is formed on the outer peripheral surface, when the thin elastic contraction tube is crimped to the outer peripheral surface and supported in the expanded state, the elastic contraction tube is torn by the projection, There is a problem that a small hole is made and the waterproof and dustproof treatment becomes insufficient. Such a breakage of the elastic shrinkable tube is caused by a projection due to welding being caught on the inner surface of the elastic shrinkable tube even when the core is removed.
[0006]
  On the other hand, in the latter core, the protrusions connecting the ring-shaped string-like body portions are provided on the inner peripheral surface, and thus the above-mentioned problems do not occur. When the cylindrical body is cut into a spiral shape, if the cutting depth is shallow, the thickness of the ridge part connecting the string parts of the adjacent ring stripes increases, and the string part of the ring stripes Therefore, it is difficult to separate them from each other, and therefore, it is very difficult to set the depth of cut with respect to the protrusion. In addition, when separating the string portions of the adjacent ring strips, the protrusions extend and cannot be separated easily, and the work of sealing the straight connection portion of the electric cable with the elastic contraction tube can be performed smoothly. However, there was a problem that work efficiency was lowered.
[0007]
  The above problems can be solved by providing a welded portion for connecting the string portions of the ring strip adjacent to the inner peripheral surface of the former core. It was difficult to spirally wind while being separably connected and to weld on the inner peripheral side.
[0008]
  For this reason, the present applicants have developed a synthetic resin core having the structure described in Japanese Patent Application No. 2000-255603. That is, as shown in FIG. 15, the core is bent into a circular ring shape following a string-like body portion 51a obtained by first bending a synthetic resin-made string-like body 51 into a circular ring shape and the string-like body portion 51a. It is formed in a cylindrical shape by continuous spiral winding in contact with the inner peripheral surface of a hollow mandrel (not shown) in a state in which the opposite end surface to the cord-like portion 51a is joined, and an adjacent circular ring shape The inner circumferential surface of the string-shaped portions 51a and 51a is welded at regular intervals in the spiral direction by a plurality of projections 62 projecting from the outer circumferential surface of the heating rotating wheel 61 disposed in one end of the hollow mandrel. 52 structure.
[0009]
  According to the synthetic resin core, the inner circumferential surface of the joint portion of the opposite end face of the circular ring-shaped string-like body portions 51a and 51a can be easily welded by the heating rotating wheel 61 during manufacturing. When the projection 62 of 61 is pressed against the inner peripheral surface of the joint portion of the string-like body portions 51a, 51a, a rectangular weld portion 52 corresponding to the cross-sectional shape of the projection 62 is formed at the joint portion, and this weld portion The four resin portions 52 are raised, and a built-up portion 52a parallel to the joining end surfaces of the string-like body portions and a built-up portion 52b orthogonal to the joining end surfaces are formed.
[0010]
  Accordingly, when the circular ring-shaped string-like body portion 51a of the core is sequentially unraveled while intermittently dividing the welded portion 52 during use, the above-described build-up portion 52b perpendicular to the joining end surface of the string-like body portions is used. When this occurs, the built-up portion 52b resists the division, so that the unraveling cannot be performed smoothly with a constant tensile force, but also due to the instantaneous strong tensile force when the built-up portion 52b is divided. There was a possibility that a part of the resin particles would be missing from the split cross section and adhere to the inner surface of the elastic contraction tube, thereby damaging the elastic contraction tube.
[0011]
  The present invention has been made in view of the above-described problems, and the object of the present invention is to smoothly and continuously unravel an electric cable with a small tensile force without damaging the elastic contraction tube. Synthetic resin core that can be wornTheAn object of the present invention is to provide a method that can be efficiently and accurately manufactured, and an apparatus that is used to perform the method.
[0012]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1A synthetic resin core manufacturing method comprising:A synthetic resin string-like body is supplied into the hollow mandrel and is slidably contacted with the inner peripheral surface of the hollow mandrel. Next, the opposing end faces of the string-like body parts curved in a circular ring shape are joined together, and then the inner peripheral surface of the facing parts joined together by the welding tool disposed in the hollow mandrel is along the joining end face. By forming a thin welded portion that is integrated so that the joint end faces can be separated by welding in a continuous spiral shape, a cylindrical shape consisting of circular ring-shaped string-like body portions that are sequentially connected in the length direction by this welding The core portion is sent out in the length direction from the hollow mandrel while being rotated in the spiral direction by the rotation driving means disposed in the hollow mandrel.
[0013]
  Claims2The invention according to the present invention is an apparatus for carrying out the above method for producing a synthetic resin core, and has an introduction port for introducing a synthetic resin string-like body into one end portion, and the introduced string-like body has a circular shape. It is curved in a circular ring shape in contact with the inner peripheral surface of one end of the wire, and is pressed toward the other end side while pressing one end surface of the curved string-like body portion and joining it to the string-like body portion previously curved in the circular ring shape. A hollow mandrel having a vertical spiral pressing end face that pushes in a spiral direction, a string-like body portion disposed in one end portion of the hollow mandrel and curved in a circular ring shape, and then in a circular ring shape. A welding tool that continuously welds the inner peripheral surface of the joint with the curved string-like body portion in the spiral direction to form a thin welded portion that can be divided between the opposing end faces, and this welding sequentially integrates in a spiral manner Circular ring-shaped string parts connected together The core portion of the cylindrical towards the other end along the inner circumferential surface of the hollow mandrel is constituted by a rotary drive means for moving while rotating spirally made.
[0014]
  In this synthetic resin core manufacturing apparatus,3In the invention according to the present invention, the inner peripheral surface of the joint portion is continuously spiral-shaped on the outer peripheral surface of the heating rotary wheel that rotates the welder in contact with the inner peripheral surface of the joint portion of the string-like body portion curved in a circular ring shape. It is characterized by having a structure in which a circular outer peripheral edge portion to be welded is provided.
[0015]
  And claims4In the invention according to the present invention, a plurality of the rotation driving means are rotated at the same speed in the same direction around each axis.FlexibleThe rotating rope bodies are configured, and one end portions of these rotating rope bodies are recessed at regular intervals in the circumferential direction on the inner peripheral surface of the hollow mandrel, and spirally from one end to the other end. Each core is disposed in an inclined groove, and a part of the outer peripheral surface protruding from the groove is brought into sliding contact with the outer peripheral surface of the cylindrical core portion to rotate the core portion.
[0016]
[Action]
  The synthetic resin core that holds the elastic contraction tube in an expanded state is formed in a cylindrical shape by spirally winding a synthetic resin string-like body in a circular ring shape, and adjacent circular ring shapes. Since the string-like body portion is welded at the inner peripheral surface side by the thin welded portion, there is no projection due to welding on the outer peripheral surface, and therefore there is a risk of damaging or damaging the elastic contraction tube. Absent.
[0017]
  When the straight connection part of the electric cable is inserted into this core and the circular ring-shaped string part of the core is unwound from the end side, the joints of the circular ring-shaped string parts are connected. Since the welded part is thin and is provided continuously in the spiral direction, it is easy to pull the welded part with a small constant tensile force, and it will be light and continuous over the entire length without causing partial defects. Can be divided. When the string-like body part is removed, the elastic shrinkable tube shrinks from its end side and crimps to the electric cable, and when the core is completely disassembled and removed, the entire surface of the outer peripheral surface of the electric cable connection part is removed. It will be in the state where it pressure-bonded and sealed.
[0018]
  In addition, the removal work of the core is previously drawn out to one end side through the inside of the core by unraveling the circular ring-shaped string-like body part of the other end portion of the core exposed from the other end side of the elastic contraction tube, By pulling the drawn string-like body portion, the circular ring-like string-like portion on the other end side is sequentially unwound while dividing the welded portions that are fixed to each other by the tensile force.
[0019]
  As the above core,AdjacentA circular ring-shaped string-like part forming a core by having a structure in which the joining end surfaces of the circular ring-shaped string-like part are locked by an upward locking protrusion and a downward locking protrusion. Are connected in sequence with the same shape in the length direction and the circumferential direction of the core, and the outer peripheral surfaces of the adjacent circular ring-shaped string-like body portions are continuously flush with each other to provide a uniform supporting force over the entire length. The elastic contraction tube can be crimped with a uniform crimping force over the entire surface.
[0020]
  Furthermore, when unraveling the circular ring-shaped string-like body portion constituting the core, an upward locking protrusion is arranged on one end surface side of the circular ring-shaped string-like body portion to be unraveled first, and this upward locking When the downward locking protrusions to be released next are engaged with the protrusions, when the circular ring string-like portions are sequentially drawn into the core, the upward locking protrusions are moved downward. The core is smoothly disassembled while easily and automatically coming off the strip.
[0021]
  To obtain a synthetic resin core for supporting such an elastic shrinkable tube, claims1, 2As described above, when a synthetic resin string-like body is fed to an inlet opening in the tangential direction of the hollow mandrel at one end of the hollow mandrel, both parallel end faces (long The end face facing the one end of the hollow mandrel is in contact with the spirally inclined vertical pressing end face disposed at the one end of the hollow mandrel, toward the other end. While being pushed forward in the spiral winding direction, it is curved into a circular ring shape by the inner peripheral surface of one end portion formed in a circular shape of the hollow mandrel, and when it makes a round along the vertical pressing end surface inclined in the spiral shape, One end surface of the string-like body portion that spirally moves toward the other end side by a pitch corresponding to the width, and the other end surface (the other end surface in the length direction) is first formed into a circular ring shape in the spiral direction. To join.
[0022]
  At this time, by providing an upward locking protrusion on one end surface side of the string-like body and a downward locking protrusion on the other end face side, the upward locking protrusion of the string-like body portion that has been spirally wound first is provided. Next, the downward locking protrusions of the string-like body part to be introduced next engage with each other, and the adjacent circular ring-like string-like body parts are continuously connected in the spiral direction by these upper and lower locking protrusions. Each core is formed with a core that is connected in a line in the length direction. Further, the inner circumferential surface at the joint portion of the adjacent circular ring-shaped string-like body portions is continuously welded in a spiral direction with a constant width by a welding tool disposed in one end portion of the hollow mandrel, and the adjacent circular ring A thin belt-like thin welded portion in which the string-like body portions are integrally connected is formed.
[0023]
  The circular ring-shaped string-like body is formed in one end of the hollow mandrel by sending a synthetic resin string-like body from the introduction port and contacting the inner peripheral surface of the one end of the hollow mandrel by the pushing force in the length direction. And is pushed forward toward the other end by the helically inclined vertical pressing end surface. The cylindrical core portion formed by the circular ring-shaped string-like body portions sequentially connected in the longitudinal direction by the above welding is a hollow mandrel while being rotated in the spiral direction by the rotation driving means disposed in the hollow mandrel. It is sent out in the length direction from and forms a long core. In addition, as the rotation driving means, a plurality of rotating rope bodies rotating in contact with a plurality of locations on the outer peripheral surface of the core portion formed in the hollow mandrel can be used.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
  Next, specific embodiments of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, the synthetic resin core A is relatively hard and has a suitable strength such as polypropylene, polyethylene or polyvinyl chloride. The string-like body 1 made of a synthetic resin having flexibility is curved and formed into a continuous spiral shape, and is formed into a cylindrical shape having a predetermined thickness and having a predetermined inner diameter and outer diameter.
[0025]
  Specifically, the string-like body 1 is formed into a string-like body portion 1a curved in a circular ring shape in a spiral direction for each predetermined length, and this circular ring-like string-like body portion 1a is sequentially adjacent to the string-like body portion. 1a, 1a has a structure in which the opposing end faces are separably joined and connected, and the inner peripheral surface of the joined portion is centered on the joining end face of the string-like body portions 1a, 1a and has a small and constant width. The thin welded portion 2 is continuously formed along the joint in the same spiral direction, and the central portion of the thin welded portion 2 in the width direction, that is, the circular ring-shaped string-like body portions 1a and 1a are joined. The core ring 1 prevents the ring-shaped string-like body part 1a from being unraveled from the end part side of the core 1 by the ultra-thin string-like thin welded part 2a in which the inner peripheral corners of the end face are integrated. Is configured to maintain a cylindrical shape. In the figure, reference numerals 2b and 2b denote resin protrusions raised on both sides of the thin welded portion 2 by melting the synthetic resin when the thin welded portion 2 is formed. It is formed in a continuous spiral shape parallel to each other on both sides of the inner surface of the joining end surface, and the thin welded portion 2 is formed in a continuous spiral shape between these protrusions 2a, 2a.
[0026]
  The length of the synthetic resin core A is longer than that of the elastic contraction tube B as shown in FIGS. 1 and 3, and the elastic contraction tube B is expanded and supported on the outer circumferential surface of the core A. In the form, both end portions of the core A protrude from the both ends of the elastic contraction tube B to the outside. Furthermore, when the elastic contraction tube B is completely contracted, the inner diameter of the elastic contraction tube B is smaller than the outer diameter of the electric cable C to be covered, and the outer peripheral surface of the connection portion C1 of the electric cable C is caused by the contraction force. On the other hand, the inner diameter of the synthetic resin core A is sufficiently larger than the outer diameter of the electric cable C, and is formed between the inner peripheral surface of the synthetic resin core A and the outer peripheral surface of the electric cable C. A relatively wide gap D is formed.
[0027]
  The synthetic resin string 1 constituting the core A is formed in a horizontally long rectangular shape having a flat cross section as shown in FIG. 2, and both end faces (both sides) parallel to each other along the length direction thereof. In the end face), an upward locking protrusion 3 having an L-shaped cross section is continuously projected over the entire length of the lower half portion of the one end face, and a downwardly inverted L-shaped cross section is provided on the upper half portion of the other end face. Similarly, the locking protrusion 4 protrudes continuously over the entire length. Specifically, the upward locking protrusion 3 has a fixed width protruding in a direction extending the width of the string-like body 1 from the lower half of the string-like body 1, and the horizontal protrusion piece 3 a It consists of a vertical protruding piece 3b of a fixed height protruding upward from the protruding end, and a small width opening opened upward between the vertical protruding piece 3b and one end surface of the string-like body 1 A stop groove 3c is formed.
[0028]
  Similarly, the downward locking protrusion 4 has a horizontal protrusion 4a that protrudes from the upper half of the other end surface of the string-like body 1 in a direction extending the width of the string-like body 1, and a horizontal protrusion piece 4a. It consists of a vertical projecting piece 4b having a fixed height projecting downward from the projecting end of the part 4a, and is opened downward between the vertical projecting piece 4b and the other end surface of the string-like body 1. A small locking groove 4c is formed.
[0029]
  And the junction part in the opposing end surface of the said adjacent circular ring-shaped string-like body parts 1a and 1a which comprise the core A which protrude in the spiral form protrudes in one circular ring-shaped string-like body part 1a. The upward locking protrusions 3 are connected to each other by engaging the downward locking protrusions 4 protruding from the other circular ring-shaped string-like body portion 1a, and the core A is deformed by this connection. The thin-walled welded portion 2 is maintained in a cylindrical shape that is not accidentally divided by pulling or crushing force in the radial direction. In the state where the string-like body 1 is curved into the circular ring-like string-like body portion 1a, the upward locking protrusion 3 is an outward locking protrusion, and the downward locking protrusion 4 is an inward engagement. The vertical protrusion 3b of the outward locking protrusion 3 is in the locking groove 4c of the inward locking protrusion 4, and the vertical protrusion 4b of the inward locking protrusion 4 is outside. It is fitted and locked in the locking groove 3c of the direction locking projection 3.
[0030]
  Next, the usage mode of the synthetic resin core A configured as described above will be described. First, as shown in FIG. 1, the elastic contraction tube B is expanded on the outer peripheral surface of the core A, and the core A is compressed. The elastic contraction tube B is supported by A in an expanded state. The core A has a length longer than the length of the elastic contraction tube B, and both end portions thereof are projected from the elastic contraction tube B by a predetermined length.
[0031]
  One electric cable C to be connected to the elastic contraction tube B is inserted and the conductive wires exposed by peeling off the ends of the electric wire covering layers C2 and C2 between the electric cable C and the other electric cable C are connected. The connecting portion C1 is positioned inside the center of the core A as shown in FIG. Furthermore, the core A has a circular ring in which the downward (inward) engaging protrusion 4 on the end of the circular ring-shaped string-like body portion 1a is adjacent to the circular ring-shaped string-like body portion 1a. While being locked to the upward (outward) locking ridge 3 of the string-like string portion 1a, on the other end side, the circular ring-shaped string portion 1a on the outermost side is upward (outward) The locking protrusion 3 is in a state of being locked to the downward (inward) locking protrusion 4 of the circular ring-shaped string portion 1a adjacent to the circular ring-shaped string portion 1a.
[0032]
  Therefore, on the other end side of the core A, the adjacent circular ring-shaped string-like body portions 1a and 1a are sequentially separated while the engaging protrusions 3 and 4 engaged with each other are removed, and the thin welded portion 2 is sequentially divided. However, it is structured so that it can be unraveled toward the hollow interior of the core A, and the circular ring-shaped string portion 1a at the other end of the core A is unwrapped by several rings in advance to end the hollow inside of the core A at one end. It is drawn in a straight line to the side and its tip is projected from one end of the core A to the outside.
[0033]
  In this state, when the tip of the string-like body portion protruding outside through the hollow of the core A is pulled, a circular ring-like string-like body portion 1a is formed from the other end side of the core A as shown in FIG. Sequentially, the thin welded portion 2 is cut into a sheared state while the upward (outward) engaging ridge 3 is detached from the downward (inward) engaging ridge 4 of the next circular ring-shaped string portion 1a. Then, it is gradually unwound and pulled out to the other end side of the core A. At this time, the thin welded portion 2 is continuous in the spiral direction over the entire length of the joint portion with a thin constant thickness on the inner peripheral surface of the joint portion between the string-like body portions 1a and 1a, and at the central portion in the width direction. Since the circular ring-shaped string-like body parts 1a and 1a are integrally connected by the thin-walled thin-wall welded part 2a, the thin-walled part is pulled by pulling the tip of the string-like body part 1a with a small constant tensile force. The ultrathin string-like thin welded portion 2a of the welded portion 2 can be easily and uniformly divided over the entire length.
[0034]
  In this way, when the core A is sequentially unwound from the other end toward the one end, the elastic ring contraction tube B supported by the core A is released according to the release of the circular ring-shaped string portion 1a. With the elastic contraction force, first, as shown in FIG. 4, the other end portion is crimped onto the insulating coating layer C2 of the other electric cable C, and then the central portion is crimped onto the connecting portion C1 between the cables. When A is completely removed, the entire length up to one end is crimped onto the insulation coating layer C2 of one electric cable C as shown in FIG. 5 so that the connection C1 of the electric cables C and C is waterproof and dustproof. It seals.
[0035]
  Next, the manufacturing apparatus and manufacturing method of the synthetic resin core A will be described. As shown in FIGS. 6 to 9, the manufacturing apparatus has an introduction port 13 (shown in FIG. 9) through which the synthetic resin string 1 is introduced at one end, and the introduced string 1 is at one end. Curved in a circular ring shape on the inner peripheral surface of the part and pressed one end face (one side end face) of the curved string-like body part 1a toward the other end side, followed by the preceding circular ring-like string-like body part 1a A hollow mandrel 10 including a ring member 11 having a vertical spiral pressing end surface 12a that pushes in a spiral direction toward the other end while joining opposite end surfaces (opposing end surfaces) to the ring-shaped string-like body portion 1a; The string-like body portion 1a which is disposed in one end portion of the hollow mandrel 10 and is curved in the form of a circular ring first, and then the string-like body portion 1a which is curved in the shape of a circular ring, and the inner peripheral surface of the joint portion are continuous. Welding tool 20 (shown in FIG. 7) that is welded in a spiral shape, and welding 2 by this welding tool 20 Therefore sequentially circular ring-shaped string-like body portion which is integrally connected to the helical directionConsist ofThe cylindrical core portion is constituted by rotational driving means 30 that moves while rotating spirally toward the other end side along the inner peripheral surface of the hollow mandrel 10.
[0036]
  The ring member 11 provided at one end of the hollow mandrel 10 has an inner diameter that is slightly smaller than the inner diameter of the hollow mandrel 10 and is arranged on the same center line as the hollow mandrel 10. The outer ring member 11A is fixed in a state where the opposite end surface is in contact with the end surface, and the inner ring member 11B is fitted on the inner peripheral surface of one end portion of the outer ring member 11A.
[0037]
  The inner ring member 11B is formed by projecting a ring portion 11b2 inserted into one end portion of the outer ring member 11A to a flange portion 11b1 fixed in contact with one end surface of the outer ring member 11A. The outer peripheral surface of the portion 11b2 is notched in a L-shaped cross section with a depth corresponding to the thickness of the string-like body 1, and a vertical end surface formed by the notch is introduced from an inlet 13 described later. While the body 1 made a round while curving from the upper peripheral end, the string-like body portion 1a curved in a circular shape was inclined spirally so as to push it toward the other end side by a distance corresponding to the width of the cord-like body 1. It is formed on the pressing end surface 12a.
[0038]
  Further, an annular space opened toward the other end side of the outer ring member 11A at the outer peripheral surface of the ring portion 11 of the inner ring member 11B and the inner peripheral surface of the outer ring member 11A cut out in an L-shaped cross section. The ring portion is formed on the upper peripheral portion of the inner ring member 11B.11b2An introduction port 13 of the string-like body 1 communicating with the upper end portion of the annular space portion 12 is formed in a tangential direction from the outer side to the outer peripheral surface of the outer circumferential surface of the outer peripheral surface. A vertical pressing end surface 12a inclined in a spiral manner is connected to the upper peripheral end. The hollow mandrel 10 including the ring member 11 is installed and fixed in a horizontal state on the machine base 5.
[0039]
  On the other hand, on the inner peripheral surface of the cylindrical hollow mandrel 10, as shown in FIG. 12, a cross section slightly inclined in a spiral direction from one end of the hollow mandrel 10 to the other end at regular intervals in the circumferential direction. C-shaped inclined grooves 14, 14... Are recessed. The inclination angle of the inclined groove 14 in the circumferential direction with respect to the axial direction of the hollow mandrel 10 is formed to be equal to the inclination angle of the vertical pressing end surface 12 a inclined in the spiral shape with respect to the axial direction of the hollow mandrel 10. That is, each inclined groove 14 is directed in a direction perpendicular to the pressing end surface 12a.
[0040]
  The hollow mandrel 10 may be formed from a single cylindrical body, but the inner peripheral surface thereof is inclined in a spiral direction from one end to the other end as described above.Inclined groove 14As shown in FIGS. 11 and 12, as shown in FIGS. 11 and 12, the annular member 10A having a constant thickness has a C-shaped cross section with a part opened on the inner peripheral surface of the member. Holes 14a are provided at regular intervals in the circumferential direction and across the front and rear end faces of the annular member 10A in parallel to the axial center direction of the hollow mandrel 10, and a plurality of the annular members 10A are stacked in series and sequentially. The inclined grooves 14 are formed by a series of holes 14a by being integrally fixed while being slightly shifted in the circumferential direction.
[0041]
  In each inclined groove 14, one end portion of a flexible cable body 31 formed by winding a metal wire in a coil shape is part of the peripheral surface of the hollow mandrel 10 from the inclined groove 14. It is arranged so as to be able to rotate in the inclined groove 14 in a state of protruding inward. Note that the protruding dimension of a part of the strip 31 protruding from the inclined groove 14 is from the inner peripheral surface of the hollow mandrel 10 to the inner peripheral surface of the outer ring member 11A having a slightly smaller diameter than the inner peripheral surface. Therefore, the outer peripheral surface of the protruding portion of the strip 31 is slid onto the outer peripheral surface of the circular ring-shaped string-like body portion 1a fed to the hollow mandrel 10 side along the inner peripheral surface of the outer ring member 11A. A core part composed of a series of circular ring-shaped string-like body parts 1a in contact with each other is configured to move toward the other end of the hollow mandrel 10 while rotating in a spiral direction.
[0042]
  As shown in FIG. 7, each rope body 31 is pulled out from the hollow mandrel 10 and expanded outward, and is arranged by a rope body rotation drive mechanism 40 installed on the machine base 5 so as to face the hollow mandrel 10. It is configured to be rotationally driven all at once in the same direction. This strip rotation driving mechanism 40 employs known means for simultaneously rotating a gear having a central portion fixed to the end portion of each strip 31 in the same direction via a meshing gear by motor driving.
[0043]
  Further, as shown in FIGS. 11 and 12, the welding tool 20 disposed in one end of the hollow mandrel 10 includes a heating rotary wheel 21 having a small circular outer peripheral edge 21a projecting from the outer peripheral surface, It comprises a cylindrical shaft 23 that rotatably supports the heating rotary wheel 21 at its tip, and a heater (not shown) that heats the rotary wheel 21 through the cylindrical shaft 23. The circular ring-shaped string-like body portions 1a and 1a formed by the guide groove 12 provided in the ring member 11 of the hollow mandrel 10 are joined in the spiral movement direction of the joint portion of the circular ring-shaped string-like body portions 1a and 1a and the circular outer peripheral edge portion 21a is joined. Slidably contact the inner peripheral surface of the circular ring-shaped string-like body portion 1a and follow the preceding circular ring-shaped string-like body portion 1a while rotating the heating rotary wheel 21 by the frictional force generated by the rotation of the circular ring-shaped string-like body portion 1a in the spiral direction. The inner circumferential surface of the joint with the circular ring-shaped string-like body portion 1a is continuously lengthed. It is configured to weld 2 in the direction.
[0044]
  6 is a string-like body supply device installed on the machine base 5 on the outer side of the ring member 11 of the hollow mandrel 10. The string-like body 1 is sandwiched by a pair of upper and lower rolls 6a and 6b while the string-like body 1 is sandwiched between them. The body 1 is continuously and forcibly fed into the introduction port of the ring member 11, and the string-like body 1 is bent in contact with the inner peripheral surface of the outer ring member 11A as described above by the feeding force. The curved circular ring-shaped string-like body portion 1a is pushed forward toward the rotation drive means 30 side (the other end side) by the helically inclined vertical pressing end surface 12a of the inner ring member 11B.
[0045]
  In order to manufacture the core A by the manufacturing apparatus configured as described above, when the synthetic resin string-like body 1 having a horizontally long rectangular cross section is supplied from the supply apparatus 6 into the introduction port 13, the string-like body 1 faces upward. One end of the annular space 12 in the ring member 11 continuing to the one side wall while sliding one end face (one side end face) projecting the locking protrusion 3 to one side wall of the inlet 13 In contact with the inclined start end (upper end) of the helically inclined vertical pressing end surface 12a in the portion, and is fed into the annular space portion 12 by the feeding force and in contact with the inner peripheral surface of the outer ring member 11A. Curved in a ring shape.
[0046]
  At this time, the string-like body 1 is pushed forward in the annular space 12 to the other end side of the outer ring member 11A by the vertical pressing end surface 12a inclined in the spiral shape, and in this state, the pressing end surface12aThe string-like body portion 1a formed into a circular ring shapePressing end face 12aWhen reaching the upper peripheral end of the other end side having a distance substantially equal to the width of the string-like body 1, the upward locking protrusion 3 projecting from the one end surface continues through the introduction passage 13. It is made to engage with the downward locking protrusion 4 protruding from the other end surface of the supplied string-like body 1.
[0047]
  Thus, after the preceding circular ring-shaped string-like body portion 1a is engaged with and connected to the circular ring-shaped string-like body portion 1a following the locking protrusions 3 and 4, these circular ring-shaped string-like body portions 1a. The inner peripheral surfaces of the joint portions 1a and 1a are continuously welded in the spiral direction along the joint portion by the circular outer peripheral edge portion 21a of the heating rotating wheel 21 that rotates by the sliding contact force with the inner peripheral surface.
[0048]
  Specifically, the central portion in the width direction is positioned on the inner peripheral surface of the circular ring-shaped string-like body portions 1a and 1a where the outer peripheral surfaces of the circular outer peripheral edge portion 21a of the heating rotating frame 21 are bonded to each other. The thin weld portion 2 having a width equal to the width of the circular outer peripheral edge portion 21a is continuously formed in the joint portion by pressing in the state. At this time, at the joint end faces of the circular ring-shaped string-like body portions 1a and 1a, the opposite inner peripheral corners are melted to form an extremely thin and thin string-like welded part 2a as shown in FIG. The string-like welded portion 2a has a structure in which the circular ring-shaped string-like body portions 1a and 1a are integrally connected and coupled so as to be separable. Further, on both sides of the thin welded portion 2, parallel strips 2b, 2b, in which the synthetic resin swells due to melting of the inner peripheral surface of the string-like body portions 1a, 1a, are formed on both sides of the joint end surface as the center. It is formed in a continuous spiral shape.
[0049]
  In this manner, the string-like body portion 1a previously curved into a circular ring shape along the guide groove 12 and the next-supplied string-like body portion 1a are connected to each other with the locking protrusions 3 and 4 thereof. While being engaged and sequentially bent into a circular ring shape as shown in FIG. 13, the inner peripheral surface of the joint portion is welded 2 in a continuous spiral shape by the circular outer peripheral edge portion 21a of the heating rotating wheel 21, and the string is formed. The inner ring portions of the joint-facing surfaces of the body-like body portions 1a and 1a are integrally connected, and the circular ring-like string-like body portions 1a and 1a are continuously spirally formed to form the core A while forming the outer ring member. It moves toward the other end while rotating in the spiral direction with its outer peripheral surface slidingly in contact with the inner peripheral surface of the other end of 11A.
[0050]
  Further, the core portion introduced into the hollow mandrel 10 is extended from the other end of the hollow mandrel 10 while being rotated in a spiral direction by a plurality of strips 31 rotating in contact with the outer peripheral surface thereof. It is sent out in the direction to form a long core A. Thus, the manufactured long core A is cut | disconnected for every predetermined length, and is made into the synthetic resin core for support of the elastic shrinkable tube B. FIG.
[0051]
  In the embodiment described above, a plurality of rotary strips 31 rotating in contact with the outer peripheral surface of the core A are employed as the rotational drive means 30 for the core A formed in the hollow mandrel 10. However, it is also possible to insert a plurality of rotating rollers from one end side of the ring member 11 of the hollow mandrel 10 and rotate the rotating rollers in contact with the inner peripheral surface of the core A formed in the hollow mandrel 10. Further, ultrasonic welding may be used as the welding tool 20 for welding the inner peripheral surfaces of the joint portions of the adjacent circular ring-shaped string-like body portions 1a and 1a.
[0052]
  Furthermore, as an engagement structure between adjacent circular ring-shaped string-like body portions 1a, 1a, an upward locking protrusion 3 having an L-shaped cross section and a downward locking protrusion 4 having an inverted L-shaped cross section are formed. However, it may be formed by inclined end faces 3A and 4A that are joined to each other as shown in FIG. 14 (a), and as shown in FIGS. 14 (b), (c), and (d), It may be formed on the inclined end faces 3B and 4B having serrated protrusions or concave and convex arc portions to be engaged. Moreover, since the circular ring-shaped string-like body portions 1a and 1a can be welded 2 at the small intervals between the inner peripheral surfaces of the joint portions as described above, the shape of the cylindrical core A can be maintained. As shown in the figure (e), they may be formed on the vertical end faces 3C and 4C.
[0053]
【The invention's effect】
  As described above, the synthetic resin core for supporting the elastic shrinkable tube of the present inventionA manufacturing method and a manufacturing apparatus according to claim 1 and claim 2.As described, the synthetic resin string-like body is supplied into the hollow mandrel from the introduction port provided at one end of the hollow mandrel, so that the string-like body portion is in sliding contact with the inner peripheral surface of the hollow mandrel. It can be curved in the shape of a circular ring by moving in the circumferential direction, and one end surface of the string-like body is slidably contacted with a spirally inclined vertical pressing end surface formed in one end portion of the hollow mandrel. However, since it moves in the circumferential direction toward the other end side, it is moved spirally toward the other end side by a pitch corresponding to the width of the string-like body when making a round along this pressing end surface, and then continuously. Thus, the cylindrical core can be accurately formed while reliably joining the other end surface of the string-like body portion introduced to one side surface of the string-like body portion that has previously made one round.
[0054]
  At this time, by providing an upward locking protrusion on one end surface side of the string-like body and a downward locking protrusion on the other end face side, the upward locking protrusion of the string-like body portion which has previously been spirally turned. The downward locking protrusions of the string-like body portion to be introduced next into the stripes are securely engaged, and the adjacent circular ring shapes are integrally connected by these upper and lower locking protrusions so that the inner and outer peripheral surfaces have their respective lengths. The core can be formed to be flush with the direction, and the welding tool is disposed in one end of the hollow mandrel. Ultra-thin, uniform-thickness welding where the inner peripheral surface of the joint part of the body part is continuously welded in the spiral direction and the joint end surfaces are integrated with the inner peripheral part of the joint end face of the circular string-like body part. Circular ring-like string-like body that can form the part accurately and is adjacent only on the inner peripheral surface side Min can be manufactured with good efficiency and detachably linked composed core a.
[0055]
  In addition, the cylindrical core portion formed by sequentially connecting the circular ring-shaped string-like body portions is rotated in the spiral direction by the rotation driving means disposed in the hollow mandrel. It is possible to efficiently produce a long core while pulling out from the hollow mandrel smoothly in the length direction at a constant speed.
[Brief description of the drawings]
FIG. 1 is a perspective view of a synthetic resin core covering an elastic contraction tube;
FIG. 2 is a partially enlarged sectional view of a synthetic resin core.
FIG. 3 is a partially cutaway perspective view showing a state where an electrical cable connecting portion is inserted,
FIG. 4 is a perspective view of a state where an elastic contraction tube is attached to a connection portion of an electric cable;
FIG. 5 is a perspective view showing a state in which the connecting portion of the electric cable is attached with an elastic contraction tube;
FIG. 6 is a simplified vertical side view of a synthetic resin core manufacturing apparatus,
FIG. 7 is a partially cutaway vertical side view of the same,
FIG. 8 is a simplified vertical side view of a ring member,
FIG. 9 is a simplified longitudinal sectional front view thereof,
FIG. 10 is a simplified front view of the entire apparatus,
FIG. 11 is a longitudinal side view of a state in which a circular ring-shaped string-like body part is formed,
FIG. 12 is a front view thereof.
FIG. 13 is a simplified perspective view thereof;
FIG. 14 is a cross-sectional view showing an engagement structure of a circular ring-shaped string-like body part;
FIG. 15 is a perspective view showing a state in which an inner peripheral surface of a circular ring-shaped string-like body portion is intermittently welded.
[Explanation of symbols]
  A Synthetic resin core
  B Elastic shrinkable tube
  C Electric cable
  C1 connection
  1 Synthetic resin string
  1a Circular ring-shaped string part
  2 Thin welded part
  2a Ultra thin string-like thin welded part
  3 Upward locking protrusion
  4 Downward locking protrusion
  10 Hollow mandrels
  11 Ring member
  12 Guide groove
  20 Welding tool
  22 Circular outer periphery
  30 Rotation drive means
  31 Ribbon

Claims

A synthetic resin string-like body is supplied into the hollow mandrel and is slidably contacted with the inner peripheral surface of the hollow mandrel. Next, the opposing end faces of the string-like body parts curved in a circular ring shape are joined together, and then the inner peripheral surface of the facing parts joined together by the welding tool disposed in the hollow mandrel is along the joining end face. By forming a thin welded portion that is integrated so that the joint end faces can be separated by welding in a continuous spiral shape, a cylindrical shape consisting of circular ring-shaped string-like body portions that are sequentially connected in the length direction by this welding A synthetic resin core manufacturing method characterized in that the core portion is sent in a length direction from a hollow mandrel while being rotated in a spiral direction by a rotation driving means disposed in the hollow mandrel. .

One end has an introduction port for introducing a synthetic resin string-like body, and the introduced string-like body is brought into contact with the inner peripheral surface of the circular one-end portion to be bent into a circular ring and one of the curved string-like body portions. A hollow mandrel provided with a vertical spiral pressing end surface that is pushed in a spiral direction toward the other end while the end surface is pressed against and joined to a string-like body portion that is previously curved in a circular ring shape, and the hollow mandrel The inner peripheral surface of the joint portion between the string-like body portion arranged in one end and curved in the form of a circular ring first and the string-like body portion curved in the shape of a circular ring is continuously welded in the spiral direction. The hollow core mandrel has a cylindrical core portion made up of a welding tool that forms a thin welded portion that can be divided between opposing end faces and a circular ring-like string-like body portion that is sequentially connected in a spiral manner by this welding. To the other end along the circumference Apparatus for manufacturing a synthetic resin core, characterized in that it is constituted by a rotary drive means for moving while rotating the spiral.

The welding tool is a circular outer peripheral edge that welds the inner peripheral surface of the joint portion in a continuous spiral form to the outer peripheral surface of the heating rotating wheel that rotates in contact with the inner peripheral surface of the joint portion of the string-like body portion curved in a circular ring shape. The apparatus for producing a synthetic resin core according to claim 2 , wherein a portion is provided.

The rotation driving means is composed of a plurality of flexible rotary rope bodies that rotate at the same speed in the same direction around each axis, and one end portion of these rotary rope bodies is connected to the inner periphery of the hollow mandrel. Each of the outer peripheral surfaces protruding from the inside of the groove is formed in a cylindrical shape by being respectively provided in grooves that are recessed at regular intervals in the circumferential direction and inclined in a spiral direction from one end to the other end. The synthetic resin core manufacturing apparatus according to claim 2 , wherein the core portion is configured to rotate by being brought into sliding contact with the outer peripheral surface of the core portion.