JP3716034B2

JP3716034B2 - Connection structure of reinforcing bar joint and reinforcing bar

Info

Publication number: JP3716034B2
Application number: JP09517696A
Authority: JP
Inventors: 定俊菊池; 加都彦坂東; 昌身中島; 清市永山
Original assignee: JFE Pipe Fitting Mfg Co Ltd
Current assignee: JFE Pipe Fitting Mfg Co Ltd
Priority date: 1996-04-17
Filing date: 1996-04-17
Publication date: 2005-11-16
Anticipated expiration: 2016-04-17
Also published as: JPH09279767A

Description

【０００１】
【発明の属する技術分野】
本発明は、コンクリート構造物の配筋に用いられる鉄筋を接続する鉄筋継手と鉄筋との接続構造に関する。
【０００２】
【従来の技術】
鉄筋を接続する鉄筋継手と鉄筋との接続構造として、たとえば、実公昭５４−４５２９２号公報に開示されているように、筒状本体の通孔の両端部からそれぞれ鉄筋を挿入し、筒状本体の軸方向中央部で両鉄筋の端面を突き合わせた状態で、両鉄筋を山型の内周形状とした半円周の内周面側に移動させて両鉄筋と筒状本体とを互いに係合させたのち、筒状本体の開口部近傍と軸方向中央部近傍に形成されている複数個のコッター挿通孔にコッターを挿通して、そのスライド面で鉄筋の表面を押圧することにより、鉄筋と筒状本体の山型形状の内周面との係合状態を確実にして、両鉄筋に引張りや曲げ荷重が作用しても、両鉄筋が筒状本体から抜け出るのを防止するように構成したものが知られている。
【０００３】
しかし、前記従来の鉄筋継手と鉄筋との接続構造は、コッター挿通孔にコッターを挿通して、押圧力を発生させることにより、鉄筋と筒状本体の山型形状の内周面との係合状態を確実にするように構成したものであるから、振動や衝撃が両鉄筋および筒状本体に負荷されると、コッターがコッター挿通孔から抜け出る方向に移動する虞れを有し、挿通孔から抜け出る方向に移動すると、係合状態を確実にする押圧力が小さくなり、鉄筋が筒状本体から抜け出るのを阻止する抜出阻止力が低下し、場合によっては抜出阻止力が消失する欠点を有している。
【０００４】
【発明が解決しようとする課題】
すなわち、従来の鉄筋継手と鉄筋との接続構造では、振動や衝撃などの外因によってコッターがコッター挿通孔から抜け出る方向に移動する虞れを有しており、抜け出る方向に移動すると、鉄筋と筒状本体の山型形状の内周面との係合状態を確実にする押圧力が小さくなり、抜出阻止力が低下あるいは消失する欠点を有している。
そこで、本発明は、振動や衝撃などの外因が負荷されても、これらの外因によって抜出阻止力が低下あるいは消失するのを防止して、鉄筋の接続直後に得た高い抜出阻止力を長期間維持することができる鉄筋継手と鉄筋との接続構造を提供することを目的としたものである。
【０００５】
【課題を解決するための手段】
前記目的を達成するために、請求項１記載の発明は、締結用の工具に係合する係合頭部と、この係合頭部に連続する軸部を有し、該軸部の前記係合頭部に近い部位に該係合頭部側から前記軸部の先端側に向かって締結用ねじ部とタッピング用刃部を順に形成したタッピング・締結兼用ねじが、筒状鉄筋継手の半径方向両側の偏心位置で該筒状鉄筋継手の軸方向に交差し、かつ軸方向の間隔を有し、さらに一部が筒状鉄筋継手の鉄筋挿入部に開口して形成された複数個のねじ挿入孔に挿入されて、前記鉄筋挿入部に挿入されている鉄筋と前記軸部が互いに係着されているとともに、前記タッピング用刃部によって前記ねじ挿入孔に形成された雌ねじ部に前記締結用ねじ部が螺着して、筒状鉄筋継手にタッピング・締結兼用ねじが締結されていることを特徴としたものである。
【０００６】
また、請求項２記載の発明は、前記タッピング・締結兼用ねじの軸部の先端部に孔あけ用の切削刃部が形成されていることを特徴としたものである。
【０００７】
請求項１記載の発明によれば、筒状鉄筋継手の鉄筋挿入部に鉄筋を挿入すると、鉄筋の外周部の一部がねじ挿入孔の開口に臨む。この状態で複数個のねじ挿入孔のそれぞれにタッピング・締結兼用ねじを挿入して、軸部の先端が前記開口に臨んでいる鉄筋の外周部の一部に当接させる。つぎに、ハンマーなどの工具によって係合頭部を打圧したりハンドプレスなどの機器によって圧入する。これにより、軸部の先端で開口に臨んでいる鉄筋の外周部の一部を削り取り、軸部の外周面の一部で鉄筋の外周部の一部を押圧して、鉄筋の外周部の一部を半径方向内側に凹入させながらねじ挿入孔に深く挿入される。このように深く挿入されることで、タッピング用刃部の先端部側がねじ挿入孔の入口に当接する。この時点で係合頭部の打圧を解除し、係合頭部にスパナなどの工具を嵌合して、タッピング・締結兼用ねじをその軸まわりに回転させる。その結果、タッピング用刃部がねじ挿入孔の入口およびその近傍に雌ねじ部を形成するとともに、形成された雌ねじ部に締結用ねじ部が螺着する手順により筒状鉄筋継手にタッピング・締結兼用ねじが締結される。
タッピング・締結兼用ねじの締結状態では、タッピング・締結兼用ねじの軸部と鉄筋は、軸部により鉄筋の外周部の一部を半径方向内側に凹入させた状態で互いに係着されているので、鉄筋が筒状鉄筋継手の鉄筋挿入部から抜け出るのを阻止するのに必要な大きい抜出阻止力が得られる。また、鉄筋と軸部との係着によって軸部の外周面の一部と鉄筋の外周部の一部との間に大きい摩擦力が発生するので、この大きい摩擦力がタッピング・締結兼用ねじの緩み止め力として作用する。
【０００８】
請求項２記載の発明によれば、係合頭部を穿孔機器の回転軸部に嵌合してタッピング・締結兼用ねじを回転させながら、孔あけ用の切削刃部によって筒状鉄筋継手の鉄筋挿入部に開口するねじ挿入孔（下孔）を形成することができる。
【０００９】
【発明の実施の形態】
以下、本発明の一実施の形態を図面に基づいて説明する。鉄筋継手と鉄筋との接続構造は、図１に示す筒状鉄筋継手１および鉄筋２と、複数本のタッピング・締結兼用ねじ３（図５参照）を備えている。筒状鉄筋継手１は、軸方向の両端を開口した内径Ｄ１が一様な鉄筋挿入部１Ａと、この鉄筋挿入部１Ａを取囲む環状の周壁１Ｂを有しており、鉄筋挿入部１Ａの内径Ｄ１は鉄筋２の外径Ｄ２より少し大きい値に設定されいる。鉄筋２として竹節２Ａを形成した竹節鉄筋が使用される。なお、前記鉄筋２の外径Ｄ２は竹節２Ａの外径を指示している。
【００１０】
図１の筒状鉄筋継手１には、軸方向の中央を対称軸Ｃとして、その両側に１対を１組とした３組のねじ挿入孔４，４、５，５、６，６が形成されている（ただし、図１には対称軸Ｃの一側のねじ挿入孔のみを示している）。これらねじ挿入孔４，４、５，５、６，６は、全体として投影平面上で千鳥状に配列され、１対のねじ挿入孔４，４と１つのねじ挿入孔５とで鉄筋挿入部１Ａの入口側のグループを構成し、１対のねじ挿入孔６，６と１つのねじ挿入孔５とで鉄筋挿入部１Ａの奥部側のグループを構成しており、それぞれの内径ｄ１は図５に示すタッピング・締結兼用ねじ３の軸部３Ｂの外径ｄ２よりも少し大きい値に設定されている。
【００１１】
ねじ挿入孔４，４は、図１および図２に示すように、筒状鉄筋継手１の縦軸線Ｃ１から半径方向両側に向けて等しい偏心量ｅをもつ偏心位置において縦軸線Ｃ１の方向に直交し、かつ軸方向の間隔ｐを有して周壁１Ｂに形成され、上下方向の中央部において一部が鉄筋挿入部１Ａに開口７しているとともに、上端部に座グリ８が形成されている。
【００１２】
ねじ挿入孔５，５は、図１および図３に示すように、筒状鉄筋継手１の縦軸線Ｃ１から半径方向両側に向けて等しい偏心量ｅ１をもつ偏心位置において縦軸線Ｃ１の方向に直交し、ねじ挿入孔６，６は、図１および図４に示すように、筒状鉄筋継手１の縦軸線Ｃ１から半径方向一側に向けて等しい偏心量ｅ２をもつ偏心位置において縦軸線Ｃ１の方向に直交して周壁１Ｂに形成されている。なお、偏心量ｅ，ｅ１，ｅ２の関係は、ｅ＞ｅ１＞ｅ２である。
【００１３】
半径方向他側のねじ挿入孔４と半径方向一側のねじ挿入孔５との間隔は前記ｐと同じ値に設定され、一方のねじ挿入孔６と半径方向他側のねじ挿入孔５との間隔およびこのねじ挿入孔５と他方のねじ挿入孔６との間隔も前記ｐと同じ値に設定されているとともに、半径方向一側のねじ挿入孔５と一方のねじ挿入孔６との間隔は前記ｐの２倍、つまり２ｐに設定され、ねじ挿入孔５，５、６，６それぞれの上下方向の中央部において一部が鉄筋挿入部１Ａに開口７している。また、上端部に座グリ８が形成されている。
【００１４】
タッピング・締結兼用ねじ３は、図５および図６に示すように、締結用の工具に係合する係合頭部３Ａと、この係合頭部３Ａに連続する軸部３Ｂを有し、該軸部３Ａの係合頭部３Ａに近い部位には、係合頭部３Ａ側から軸部３Ｂの先端側に向かって締結用ねじ部３Ｃとタッピング用刃部３Ｄが半径方向外側に少し張り出して連続して形成されている。また、軸部３Ｂの先端部は上向き円錐状に凹入されている。なお、図１において、１１はグラウト注入孔を示し、このグラウト注入孔１１から鉄筋継手と鉄筋の接続後にグラウト注入させて鉄筋継手と鉄筋の接続を更に強固にさせてもよいが、必ずしもグラウト注入させなくてもよい。また、このグラウト注入孔１１を鉄筋３の挿入状態確認用の孔として機能させてもよい。なお、グラウト注入させない場合は、このグラウト注入孔１１は必ずしも必要とするものではない。
【００１５】
このような構成であれば、筒状鉄筋継手１における鉄筋挿入部１Ａの両端開口から竹節鉄筋２，２を挿入して、それぞれの先端を対称軸Ｃ付近に位置させる。これにより、竹節鉄筋２，２の竹節２Ａが複数個のねじ挿入孔４，４、５，５、６，６から軸方向に離れて、竹節鉄筋２，２の体部２Ｂの一部が各ねじ挿入孔４，４、５，５、６，６における上下方向中央部の開口７に臨む位置関係になる。
【００１６】
つぎに、各ねじ挿入孔４，４、５，５、６，６にタッピング・締結兼用ねじ３を挿入して、図２、図３および図４の仮想線で示すように、軸部３Ｂの先端縁部を開口７に臨んでいる鉄筋２における体部２Ｂの外周部の一部に当接させる。
【００１７】
つづいて、ハンマーなどの工具によって、各タッピング・締結兼用ねじ３の係合頭部３Ａを打圧する。この打圧は、半径方向一側のねじ挿入孔４に挿入されているタッピング・締結兼用ねじ３→半径方向他側のねじ挿入孔４に挿入されているタッピング・締結兼用ねじ３→半径方向一側のねじ挿入孔５に挿入されているタッピング・締結兼用ねじ３→一方のねじ挿入孔６に挿入されているタッピング・締結兼用ねじ３→半径方向他側のねじ挿入孔５に挿入されているタッピング・締結兼用ねじ３→他方のねじ挿入孔６に挿入されているタッピング・締結兼用ねじ３の順序で行うことが望ましい。
【００１８】
ハンマーなどの工具によって係合頭部３Ａを打圧された各タッピング・締結兼用ねじ３は、軸部３Ｂの先端で開口７に臨んでいる鉄筋３における体部２Ｂの外周部の一部を削り取り、かつ軸部３Ｂの外周面の一部で体部２Ｂの外周部の一部を押圧して、図７に示すように、体部２Ｂの外周部の一部を半径方向内側に凹入９させながら、図８、図９および図１０に示すように各ねじ挿入孔４，４、５，５、６，６に深く挿入され、タッピング用刃部３Ｄの先端部側が各ねじ挿入孔４，４、５，５、６，６の入口に当接する。この時点で係合頭部３Ａの打圧を止める。なお、鉄筋３が宙吊りで不安定な状態の場合は、ハンマーなどの工具によって係合頭部３Ａを打圧する作業を採用できないので、ハンドプレスなどの機器を用いて圧入すればよい。
【００１９】
つぎに、係合頭部３Ａにスパナなどの工具（図示省略）を嵌合して、各タッピング・締結兼用ねじ３をその軸まわりに回転させる。その結果、図１１に示すように、タッピング用刃部３Ｄが各ねじ挿入孔４，４、５，５、６，６の入口およびその近傍に２〜３山程度の雌ねじ部１０を形成する。さらに、各タッピング・締結兼用ねじ３の軸まわりに回転を継続して行うことで、図１２、図１３および図１４に示すように、雌ねじ部１０に締結用ねじ部３Ｃが螺着し、かつ係合頭部３Ａが座グリ８に着座して、筒状鉄筋継手１に各タッピング・締結兼用ねじ３が締結された鉄筋継手１と鉄筋２，２との接続状態を得ることができる。また、タッピング用刃部３Ｄによって、各ねじ挿入孔４，４、５，５、６，６の入口およびその近傍に２〜３山程度の少ない山数の雌ねじ部１０を形成するようにしているので、雌ねじ部１０形成時におけるタッピング用刃部３Ｄの切削抵抗が小さく抑えられるから、雌ねじ部１０の形成途中でタッピング・締結兼用ねじ３が折損する不都合の発生を防止できる。
【００２０】
なお、体部２Ｂの外周部の一部が凹入９されることで、体部２Ｂの横断面積が僅かに縮小されるが、強度的な問題が発生せず、横断面積の僅かな縮小が無視できることを強度計算および引張テストにより確認している。
【００２１】
前記タッピング・締結兼用ねじ３の締結状態では、各タッピング・締結兼用ねじ３の軸部３Ｂと鉄筋２における体部２Ｂの外周部の一部は、軸部３Ｂにより体部２Ｂの外周部の一部を半径方向内側に凹入９させた状態で互いに係着されているので、鉄筋２，２が筒状鉄筋継手１の鉄筋挿入部１Ａから抜け出るのを阻止するのに必要な大きい抜出阻止力が得られる。また、体部２Ｂの外周の一部と軸部３Ｂとの係着によって、軸部３Ｂの外周面の一部と体部２Ｂの外周の一部との間に大きい摩擦力が発生するので、この大きい摩擦力が各タッピング・締結兼用ねじ３の緩み止め力として作用する。このため、振動や衝撃などの外因が鉄筋２および筒状鉄筋継手１に負荷されても、各タッピング・締結兼用ねじ３の締結状態が損なわれることはない。したがって、抜出阻止力が低下あるいは消失するのを確実に防止して、鉄筋２，２の接続直後に得た高い抜出阻止力を長期間維持することができる。
【００２２】
図１５および図１６は、タッピング・締結兼用ねじ３の他の実施の形態を示し、タッピング・締結兼用ねじ３の軸部３Ｂの先端部にドリル部３Ｅが形成されている。このように構成されたタッピング・締結兼用ねじ３を使用することによって、係合頭部３Ａを穿孔機器（図示省略）の回転軸部に嵌合して、タッピング・締結兼用ねじ３を回転させながら、ドリル部３Ｅによって筒状鉄筋継手１の鉄筋挿入部１Ａに開口するねじ挿入孔（下孔）４，４、５，５、６，６を形成することができる。これにより、ハンマーなどの工具によって係合頭部３Ａを打圧したりハンドプレスなどの機器によって圧入する作業を省略することが可能になる。
【００２３】
図１７および図１８は、タッピング・締結兼用ねじ３のさらに異なる実施の形態を示し、タッピング・締結兼用ねじ３の軸部３Ｂの先端部にエンドミル部３Ｆが形成されている。このように構成されたタッピング・締結兼用ねじ３を使用することによって、係合頭部３Ａを穿孔機器（図示省略）の回転軸部に嵌合して、タッピング・締結兼用ねじ３を回転させながら、エンドミル部３Ｆによって筒状鉄筋継手１の鉄筋挿入部１Ａに開口するねじ挿入孔（下孔）４，４、５，５、６，６を形成することができる。これにより、ハンマーなどの工具によって係合頭部３Ａを打圧したりハンドプレスなどの機器によって圧入する作業を省略することが可能になる。
【００２４】
なお、前記実施の形態では、筒状鉄筋継手１の軸方向の中央を対称軸Ｃとして、鉄筋挿入部１Ａの両側から鉄筋２，２を挿入しているが、鉄筋挿入部１Ａの片側から鉄筋２を挿入する筒状鉄筋継手１にも適用できる。また、１対を１組とした３組のねじ挿入孔４，４、５，５、６，６によって、鉄筋挿入部１Ａの入口側と鉄筋挿入部１Ａの奥部側の２つのグループを構成しているが、３つねじ挿入孔を千鳥状に配列した１つのグループを最低限度として構成しておけばよい。さらに、ねじ挿入孔４，４、５，５、６，６の偏心量を１つの値（たとえばｅ）に統一してもよい。ただし、前記実施の形態のように、鉄筋挿入部１Ａの入口側の偏心量よりも奥部側の偏心量を漸次大きくすることによって、振動や衝撃などの外因影響を受けやすい奥部側の抜出阻止力を高めて、抜出阻止力をより一層大きくすることができる。さらに、下向き円錐状に形成している軸部３Ｂの先端部は、フラット形あるいは下向き円錐状部の先端に突部を突設した形であってもよい。勿論、前記実施の形態で使用している竹節鉄筋２に代えて、網目状節やねじ状節をもつ他の異形鉄筋あるいは表面の平らな鉄筋の接続にも適用可能である。
【００２５】
【発明の効果】
以上説明したように、請求項１記載の発明は、タッピング・締結兼用ねじを締結することで、タッピング・締結兼用ねじの軸部と鉄筋の外周部の一部が軸部により鉄筋の外周部の一部を半径方向内側に凹入させた状態で互いに係着されるので、鉄筋が筒状鉄筋継手の鉄筋挿入部から抜け出るのを阻止するのに必要な大きい抜出阻止力が得られる。また、鉄筋の外周の一部と軸部との係着によって、軸部の外周面の一部と鉄筋の外周の一部との間に大きい摩擦力が発生するので、この大きい摩擦力がタッピング・締結兼用ねじの緩み止め力として作用することになって、振動や衝撃などの外因が鉄筋および筒状鉄筋継手に負荷されても、タッピング・締結兼用ねじの締結状態が損なわれることはない。したがって、抜出阻止力が低下あるいは消失するのを確実に防止して、鉄筋の接続直後に得た高い抜出阻止力を長期間維持することができる。
【００２６】
請求項２記載の発明は、係合頭部を穿孔機器の回転軸部に嵌合して、タッピング・締結兼用ねじを回転させながら、孔あけ用の切削刃部によって筒状鉄筋継手にねじ挿入孔（下孔）を形成することができるので、ハンマーなどの工具によって係合頭部を打圧したりハンドプレスなどの機器によって圧入する作業を省略することが可能になる。
【図面の簡単な説明】
【図１】筒状鉄筋継手の一実施の形態を示す平面図である。
【図２】図１のＡ−Ａ線拡大断面図である。
【図３】図１のＢ−Ｂ線拡大断面図である。
【図４】図１のＤ−Ｄ線拡大断面図である。
【図５】タッピング・締結兼用ねじの一実施の形態を示す拡大正面図である。
【図６】図５のＥ−Ｅ線断面図である。
【図７】鉄筋の外周部に形成される半径方向内側への凹入を示す拡大横断面図である。
【図８】タッピング・締結兼用ねじの挿入途中の状態を示す図２相当図である。
【図９】タッピング・締結兼用ねじの挿入途中の状態を示す図３相当図である。
【図１０】タッピング・締結兼用ねじの挿入途中の状態を示す図４相当図である。
【図１１】雌ねじ部の形成状態を示す部分拡大断面図である。
【図１２】タッピング・締結兼用ねじの締結完了状態を示す図２相当図である。
【図１３】タッピング・締結兼用ねじの締結完了状態を示す図３相当図である。
【図１４】タッピング・締結兼用ねじの締結完了状態を示す図４相当図である。
【図１５】タッピング・締結兼用ねじの他の実施の形態を示す正面図である。
【図１６】図１５のＦ−Ｆ矢視図である。
【図１７】タッピング・締結兼用ねじのさらに異なる実施の形態を示す正面図である。
【図１８】図１５のＧ−Ｇ矢視図である。
【符号の説明】
１筒状鉄筋継手
１Ａ鉄筋挿入部
２鉄筋
３タッピング・締結兼用ねじ
３Ａタッピング・締結兼用ねじの係合頭部
３Ｂタッピング・締結兼用ねじの軸部
３Ｃタッピング・締結兼用ねじの締結用ねじ部
３Ｄタッピング・締結兼用ねじのタッピング用刃部
４ねじ挿入孔
５ねじ挿入孔
６ねじ挿入孔
７開口
１０雌ねじ部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a connection structure between a reinforcing bar joint and a reinforcing bar for connecting reinforcing bars used for reinforcement of a concrete structure.
[0002]
[Prior art]
For example, as disclosed in Japanese Utility Model Publication No. 54-45292, as a connecting structure between a reinforcing bar joint and a reinforcing bar that connects the reinforcing bars, the reinforcing bars are respectively inserted from both ends of the through hole of the cylindrical main body. In the state where the end faces of both rebars are in contact with each other in the axial center, move both rebars to the inner circumference side of the semicircular shape with a mountain-shaped inner circumference, and engage both rebars and the tubular body with each other After that, the cotter is inserted into a plurality of cotter insertion holes formed in the vicinity of the opening of the cylindrical main body and in the vicinity of the central portion in the axial direction, and the surface of the rebar is pressed with the slide surface, thereby Ensuring that the tubular body is engaged with the chevron-shaped inner peripheral surface, even if tensile and bending loads are applied to both reinforcing bars, both reinforcing bars are prevented from coming out of the tubular body. Things are known.
[0003]
However, the connection structure between the conventional reinforcing bar joint and the reinforcing bar is that the cotter is inserted into the cotter insertion hole to generate a pressing force, thereby engaging the reinforcing bar with the chevron-shaped inner peripheral surface of the cylindrical body. Since it is configured to ensure the state, when vibration or impact is applied to both the reinforcing bars and the cylindrical main body, there is a possibility that the cotter may move in the direction of coming out of the cotter insertion hole. When moving in the direction of withdrawal, the pressing force that ensures the engagement state is reduced, the extraction prevention force that prevents the reinforcing bars from coming out of the cylindrical body is reduced, and in some cases the extraction prevention force disappears. Have.
[0004]
[Problems to be solved by the invention]
That is, in the conventional connection structure between a reinforcing bar joint and a reinforcing bar, there is a risk that the cotter may move in the direction of coming out of the cotter insertion hole due to external factors such as vibration and impact. The pressing force that ensures the engagement state with the chevron-shaped inner peripheral surface of the main body is reduced, and the pull-out preventing force is reduced or eliminated.
Therefore, the present invention prevents the extraction preventing force from being reduced or lost due to external factors such as vibrations and shocks, and prevents a high extraction preventing force obtained immediately after connecting the reinforcing bars. An object of the present invention is to provide a connection structure between a reinforcing bar joint and a reinforcing bar that can be maintained for a long time.
[0005]
[Means for Solving the Problems]
In order to achieve the object, an invention according to claim 1 includes an engaging head that engages with a fastening tool, and a shaft portion that is continuous with the engaging head, and the engagement of the shaft portion. A tapping / fastening screw in which a fastening screw portion and a tapping blade portion are formed in this order from the engaging head side toward the distal end side of the shaft portion in a portion close to the joint head is a radial direction of the cylindrical reinforcing bar joint A plurality of screw insertions formed by crossing in the axial direction of the cylindrical reinforcing bar joint at the eccentric positions on both sides and having an axial interval, and a part of which is opened to the reinforcing bar insertion part of the cylindrical reinforcing bar joint The reinforcing bar inserted into the hole and the shaft inserted into the reinforcing bar insertion part are engaged with each other, and the fastening screw is connected to the female screw part formed in the screw insertion hole by the tapping blade part The part is screwed, and the tapping / fastening screw is fastened to the tubular rebar joint It is obtained by the features and.
[0006]
The invention according to claim 2 is characterized in that a cutting blade portion for drilling is formed at a tip portion of a shaft portion of the tapping / fastening screw.
[0007]
According to the first aspect of the present invention, when the reinforcing bar is inserted into the reinforcing bar insertion part of the cylindrical reinforcing bar joint, a part of the outer peripheral part of the reinforcing bar faces the opening of the screw insertion hole. In this state, a tapping / fastening screw is inserted into each of the plurality of screw insertion holes, and is brought into contact with a part of the outer peripheral portion of the reinforcing bar whose tip end faces the opening. Next, the engaging head is pressed with a tool such as a hammer or press-fitted with a device such as a hand press. As a result, a part of the outer peripheral part of the reinforcing bar facing the opening at the tip of the shaft part is scraped off, and a part of the outer peripheral part of the reinforcing bar is pressed by a part of the outer peripheral surface of the shaft part, thereby The part is inserted deeply into the screw insertion hole while being recessed inward in the radial direction. By inserting deeply in this way, the tip end side of the tapping blade part comes into contact with the inlet of the screw insertion hole. At this time, the pressure applied to the engaging head is released, a tool such as a spanner is fitted into the engaging head, and the tapping / fastening screw is rotated about its axis. As a result, the tapping blade portion forms a female screw portion at and near the entrance of the screw insertion hole, and the tapping and fastening screw is attached to the cylindrical reinforcing bar joint by a procedure in which the fastening screw portion is screwed to the formed female screw portion. Is concluded.
In the tightened state of the tapping / fastening combined screw, the shaft portion and the reinforcing bar of the tapping / fastening combined screw are engaged with each other in a state where a part of the outer peripheral portion of the reinforcing bar is recessed radially inward by the shaft portion. Thus, a large pull-out preventing force necessary to prevent the reinforcing bars from coming out from the reinforcing bar insertion portion of the tubular reinforcing bar joint can be obtained. In addition, since a large frictional force is generated between a part of the outer peripheral surface of the shaft part and a part of the outer peripheral part of the reinforcing bar due to the engagement between the reinforcing bar and the shaft part, this large frictional force is applied to the tapping and fastening screw. Acts as a locking force.
[0008]
According to the second aspect of the present invention, the reinforcing bar of the cylindrical reinforcing bar joint is formed by the cutting blade part for drilling while the engaging head is fitted to the rotating shaft part of the drilling device and the tapping / fastening screw is rotated. A screw insertion hole (a lower hole) that opens in the insertion portion can be formed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The connection structure between the reinforcing bar joint and the reinforcing bar includes the cylindrical reinforcing bar joint 1 and the reinforcing bar 2 shown in FIG. 1 and a plurality of tapping / fastening screws 3 (see FIG. 5). The cylindrical reinforcing bar joint 1 has a reinforcing bar insertion part 1A having a uniform inner diameter D1 with both ends opened in the axial direction and an annular peripheral wall 1B surrounding the reinforcing bar insertion part 1A. The inner diameter of the reinforcing bar insertion part 1A D1 is set to a value slightly larger than the outer diameter D2 of the reinforcing bar 2. As the reinforcing bar 2, a bamboo reinforcing bar having a bamboo knob 2 A is used. The outer diameter D2 of the reinforcing bar 2 indicates the outer diameter of the bamboo knot 2A.
[0010]
1 is formed with three sets of screw insertion holes 4, 4, 5, 5, 6, 6 with the center in the axial direction as the axis of symmetry C and one pair on each side. (However, FIG. 1 shows only the screw insertion hole on one side of the symmetry axis C). These screw insertion holes 4, 4, 5, 5, 6, 6 are arranged in a zigzag pattern on the projection plane as a whole, and a pair of screw insertion holes 4, 4 and one screw insertion hole 5 constitute a reinforcing bar insertion portion. A group on the inlet side of 1A is constituted, and a pair of screw insertion holes 6, 6 and one screw insertion hole 5 constitute a group on the back side of the reinforcing bar insertion portion 1A, and each inner diameter d1 is shown in FIG. 5 is set to a value slightly larger than the outer diameter d2 of the shaft portion 3B of the tapping / fastening screw 3 shown in FIG.
[0011]
As shown in FIGS. 1 and 2, the screw insertion holes 4 and 4 are orthogonal to the direction of the vertical axis C1 at an eccentric position having an equal eccentricity e from the longitudinal axis C1 of the cylindrical rebar joint 1 toward both sides in the radial direction. In addition, it is formed on the peripheral wall 1B with an axial interval p, and a part of the central portion in the vertical direction has an opening 7 in the reinforcing bar insertion portion 1A, and a counterbore 8 is formed at the upper end. .
[0012]
As shown in FIGS. 1 and 3, the screw insertion holes 5 and 5 are orthogonal to the direction of the vertical axis C1 at an eccentric position having an equal eccentricity e1 from the longitudinal axis C1 of the cylindrical rebar joint 1 toward both sides in the radial direction. As shown in FIGS. 1 and 4, the screw insertion holes 6 and 6 are arranged along the longitudinal axis C1 at an eccentric position having an equal eccentric amount e2 from the longitudinal axis C1 of the cylindrical reinforcing bar joint 1 toward one side in the radial direction. It is formed in the peripheral wall 1B orthogonal to the direction. The relationship between the eccentric amounts e, e1, and e2 is e>e1> e2.
[0013]
The distance between the screw insertion hole 4 on the other side in the radial direction and the screw insertion hole 5 on the one side in the radial direction is set to the same value as p, and the distance between the screw insertion hole 6 on one side and the screw insertion hole 5 on the other side in the radial direction is set. The interval and the interval between the screw insertion hole 5 and the other screw insertion hole 6 are also set to the same value as p, and the interval between the screw insertion hole 5 on one side in the radial direction and the one screw insertion hole 6 is It is set to twice the p, that is, 2p, and a part of the screw insertion holes 5, 5, 6, 6 has an opening 7 in the reinforcing bar insertion portion 1 A at the center in the vertical direction. A counterbore 8 is formed at the upper end.
[0014]
As shown in FIGS. 5 and 6, the tapping / fastening screw 3 has an engaging head 3A that engages with a fastening tool, and a shaft portion 3B that is continuous with the engaging head 3A. At a portion near the engaging head 3A of the shaft portion 3A, a fastening screw portion 3C and a tapping blade portion 3D slightly protrude outward in the radial direction from the engaging head 3A side toward the distal end side of the shaft portion 3B. It is formed continuously. Moreover, the front-end | tip part of the axial part 3B is recessed in the upward cone shape. In FIG. 1, reference numeral 11 denotes a grout injection hole. The grout injection hole 11 may be injected after the connection between the reinforcing bar joint and the reinforcing bar to further strengthen the connection between the reinforcing bar joint and the reinforcing bar. You don't have to. Further, the grout injection hole 11 may function as a hole for checking the insertion state of the reinforcing bar 3. In the case where the grouting is not performed, the grouting hole 11 is not necessarily required.
[0015]
With such a configuration, the bamboo rebars 2 and 2 are inserted from both end openings of the reinforcing bar insertion portion 1 A in the tubular reinforcing bar joint 1, and the respective tips are positioned near the symmetry axis C. As a result, the bamboo nodes 2A of the bamboo bars 2 and 2 are separated from the plurality of screw insertion holes 4, 4, 5, 5, 6 and 6 in the axial direction, and a part of the body part 2B of the bamboo nodes 2 and 2 is separated from each other. The screw insertion holes 4, 4, 5, 5, 6, 6 have a positional relationship facing the opening 7 at the center in the vertical direction.
[0016]
Next, the tapping / fastening screw 3 is inserted into each of the screw insertion holes 4, 4, 5, 5, 6 and 6, and as shown by the phantom lines in FIGS. The front edge is brought into contact with a part of the outer peripheral portion of the body part 2B in the reinforcing bar 2 facing the opening 7.
[0017]
Subsequently, the engaging head 3A of each tapping and fastening screw 3 is struck with a tool such as a hammer. The tapping / fastening combined screw 3 inserted in the screw insertion hole 4 on one side in the radial direction → the tapping / fastening combined screw 3 inserted in the screw insertion hole 4 on the other side in the radial direction → one in the radial direction. Tapping / fastening screw 3 inserted in the screw insertion hole 5 on the side → Tapping / fastening screw 3 inserted in the screw insertion hole 6 → The screw insertion hole 5 on the other side in the radial direction It is desirable that the tapping / fastening combined screw 3 → the tapping / fastening combined screw 3 inserted in the other screw insertion hole 6 is used in this order.
[0018]
Each tapping / fastening screw 3 struck by the engaging head 3A with a tool such as a hammer scrapes off a part of the outer peripheral portion of the body portion 2B of the reinforcing bar 3 facing the opening 7 at the tip of the shaft portion 3B. Further, a part of the outer peripheral part of the body part 2B is pressed by a part of the outer peripheral surface of the shaft part 3B, and as shown in FIG. 7, a part of the outer peripheral part of the body part 2B is recessed radially inward 9. 8, 9, and 10, the screw insertion holes 4, 4, 5, 5, 6, and 6 are deeply inserted, and the tip of the tapping blade 3 D is connected to each screw insertion hole 4. It abuts on the inlets of 4, 5, 5, 6 and 6. At this time, the striking pressure of the engaging head 3A is stopped. In addition, when the rebar 3 is suspended in an unstable state, it is not possible to employ an operation of hitting the engaging head 3A with a tool such as a hammer. Therefore, press fitting may be performed using a device such as a hand press.
[0019]
Next, a tool such as a spanner (not shown) is fitted to the engaging head 3A, and each tapping / fastening screw 3 is rotated about its axis. As a result, as shown in FIG. 11, the tapping blade portion 3D forms a female thread portion 10 having about two to three threads at the inlets of the screw insertion holes 4, 4, 5, 5, 6, 6 and in the vicinity thereof. Further, by continuing to rotate around the axis of each tapping / fastening screw 3, the fastening screw portion 3 C is screwed onto the female screw portion 10 as shown in FIGS. 12, 13, and 14, and The engagement head 3A is seated on the spot facing 8, and the connection state between the reinforcing bar joint 1 and the reinforcing bars 2 and 2 in which the tapping and fastening screws 3 are fastened to the tubular reinforcing bar joint 1 can be obtained. Further, the tapping blade 3D forms a female thread portion 10 having a small number of threads of about 2 to 3 threads at and near the inlets of the screw insertion holes 4, 4, 5, 5, 6 and 6. Therefore, since the cutting resistance of the tapping blade portion 3D when the female screw portion 10 is formed can be suppressed to be small, it is possible to prevent the inconvenience that the tapping / fastening screw 3 is broken during the formation of the female screw portion 10.
[0020]
In addition, although a part of the outer peripheral part of the body part 2B is recessed 9, the transverse area of the body part 2B is slightly reduced, but there is no problem in strength, and the transverse area is slightly reduced. It can be ignored by strength calculation and tensile test.
[0021]
In the fastening state of the tapping / fastening screw 3, a part of the outer peripheral portion of the body portion 2 B of the shaft portion 3 B and the reinforcing bar 2 is part of the outer peripheral portion of the body portion 2 B by the shaft portion 3 B. Since the parts are engaged with each other in a state of being recessed 9 inward in the radial direction, the large pullout prevention necessary to prevent the reinforcing bars 2 and 2 from coming out of the reinforcing bar insertion part 1A of the tubular reinforcing bar joint 1 Power is obtained. Further, due to the engagement between a part of the outer periphery of the body part 2B and the shaft part 3B, a large frictional force is generated between a part of the outer peripheral surface of the shaft part 3B and a part of the outer periphery of the body part 2B. This large frictional force acts as a locking force for each tapping / fastening screw 3. For this reason, even if external factors such as vibration and impact are applied to the reinforcing bar 2 and the cylindrical reinforcing bar joint 1, the fastening state of each tapping / fastening screw 3 is not impaired. Therefore, it is possible to reliably prevent the withdrawal prevention force from being lowered or disappeared, and to maintain the high withdrawal prevention force obtained immediately after connecting the reinforcing bars 2 and 2 for a long period of time.
[0022]
15 and 16 show another embodiment of the tapping / fastening / combining screw 3 in which a drill portion 3E is formed at the tip of the shaft portion 3B of the tapping / fastening / combining screw 3. By using the tapping / fastening screw 3 configured as described above, the engaging head 3A is fitted to the rotary shaft portion of the drilling device (not shown), and the tapping / fastening screw 3 is rotated. The screw insertion holes (bottom holes) 4, 4, 5, 5, 6, 6 opening to the reinforcing bar insertion part 1 A of the cylindrical reinforcing bar joint 1 can be formed by the drill part 3 E. As a result, it is possible to omit the work of pressing the engaging head 3A with a tool such as a hammer or press-fitting with a device such as a hand press.
[0023]
FIGS. 17 and 18 show still another embodiment of the tapping / fastening combined screw 3, and an end mill portion 3 F is formed at the tip of the shaft portion 3 B of the tapping / fastening combined screw 3. By using the tapping / fastening screw 3 configured as described above, the engaging head 3A is fitted to the rotary shaft portion of the drilling device (not shown), and the tapping / fastening screw 3 is rotated. The screw insertion holes (lower holes) 4, 4, 5, 5, 6, 6 that open to the reinforcing bar insertion portion 1 A of the tubular reinforcing bar joint 1 can be formed by the end mill 3 F. As a result, it is possible to omit the work of pressing the engaging head 3A with a tool such as a hammer or press-fitting with a device such as a hand press.
[0024]
In the embodiment described above, the reinforcing bars 2 and 2 are inserted from both sides of the reinforcing bar insertion portion 1A with the axial center of the cylindrical reinforcing bar joint 1 as the axis of symmetry C, but the reinforcing bars are inserted from one side of the reinforcing bar insertion portion 1A. It is applicable also to the cylindrical reinforcing bar joint 1 which inserts 2. Moreover, two groups of the entrance side of the reinforcing bar insertion part 1A and the back side of the reinforcing bar insertion part 1A are constituted by three sets of screw insertion holes 4, 4, 5, 5, 6, and 6 as one pair. However, one group in which three screw insertion holes are arranged in a staggered manner may be configured as a minimum. Furthermore, the amount of eccentricity of the screw insertion holes 4, 4, 5, 5, 6, 6 may be unified to one value (for example, e). However, as in the above-described embodiment, by gradually increasing the amount of eccentricity on the back side from the amount of eccentricity on the inlet side of the reinforcing bar insertion portion 1A, the back side can be easily affected by external factors such as vibration and impact. It is possible to increase the ejection preventing force and further increase the withdrawal preventing force. Furthermore, the tip portion of the shaft portion 3B formed in a downward conical shape may be a flat shape or a shape in which a protrusion is provided at the tip of the downward conical portion. Of course, instead of the bamboo rebar 2 used in the above-described embodiment, the present invention can also be applied to connection of other deformed rebars having a mesh-like node or a screw-like node or a rebar having a flat surface.
[0025]
【The invention's effect】
As described above, according to the first aspect of the present invention, by tapping the tapping / fastening / combining screw, the shaft portion of the tapping / fastening / combining screw and a part of the outer peripheral portion of the reinforcing bar are part of the outer peripheral portion of the reinforcing bar by the shaft portion. Since the portions are engaged with each other in a state of being recessed inward in the radial direction, a large pulling out prevention force necessary to prevent the reinforcing bars from coming out from the reinforcing bar insertion portion of the tubular reinforcing bar joint can be obtained. In addition, since a large frictional force is generated between a part of the outer peripheral surface of the shaft part and a part of the outer periphery of the reinforcing bar due to the engagement between a part of the outer periphery of the reinforcing bar and the shaft part, this large frictional force is tapped. -Even if external factors such as vibration and impact are applied to the reinforcing bar and the tubular reinforcing bar joint, the fastening state of the tapping / fastening screw is not impaired even if it acts as a locking force for the fastening screw. Therefore, it is possible to reliably prevent the withdrawal prevention force from being lowered or disappeared, and to maintain the high withdrawal prevention force obtained immediately after connecting the reinforcing bars for a long period of time.
[0026]
According to the second aspect of the present invention, the engaging head is fitted to the rotary shaft portion of the drilling device, and the screw is inserted into the cylindrical reinforcing bar joint by the cutting blade portion for drilling while rotating the tapping / fastening screw. Since the hole (the lower hole) can be formed, it is possible to omit the work of hitting the engaging head with a tool such as a hammer or press-fitting with a device such as a hand press.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a tubular reinforcing bar joint.
FIG. 2 is an enlarged cross-sectional view taken along line AA of FIG.
FIG. 3 is an enlarged cross-sectional view taken along line BB in FIG.
4 is an enlarged sectional view taken along line DD of FIG.
FIG. 5 is an enlarged front view showing an embodiment of a tapping / fastening screw.
6 is a cross-sectional view taken along the line EE of FIG.
FIG. 7 is an enlarged cross-sectional view showing a recess inward in the radial direction formed in the outer peripheral portion of the reinforcing bar.
8 is a view corresponding to FIG. 2, showing a state in the middle of insertion of the tapping / fastening screw.
9 is a view corresponding to FIG. 3, showing a state in the middle of insertion of the tapping / fastening screw.
FIG. 10 is a view corresponding to FIG. 4 and showing a state in the middle of inserting the tapping / fastening screw.
FIG. 11 is a partial enlarged cross-sectional view showing a formation state of the female screw portion.
FIG. 12 is a view corresponding to FIG. 2 and illustrating a fastening completion state of the tapping / fastening screw.
FIG. 13 is a view corresponding to FIG. 3 and showing a fastening completion state of the tapping / fastening combined screw.
FIG. 14 is a view corresponding to FIG. 4 and illustrating a fastening completion state of the tapping / fastening screw.
FIG. 15 is a front view showing another embodiment of the tapping / fastening screw.
16 is a FF arrow view of FIG.
FIG. 17 is a front view showing still another embodiment of the tapping / fastening screw.
18 is a view taken along the line GG in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tubular reinforcing bar joint 1A Reinforcing bar insertion part 2 Reinforcing bar 3 Tapping / fastening combined screw 3A Tapping / fastening combined screw head 3B Tapping / fastening combined screw shaft 3C Tapping / fastening combined screw tightening screw 3D Tapping -Tapping blade for fastening screw 4 Screw insertion hole 5 Screw insertion hole 6 Screw insertion hole 7 Opening 10 Female thread

Claims

An engagement head that engages with the fastening tool, and a shaft portion that is continuous with the engagement head, and the shaft portion is located near the engagement head from the engagement head side. The tapping / fastening screw, in which a fastening screw part and a tapping blade part are formed in order toward the tip of the part, intersects the axial direction of the tubular rebar joint at eccentric positions on both sides in the radial direction of the tubular rebar joint. And a reinforcing bar inserted in the reinforcing bar insertion part by being inserted into a plurality of screw insertion holes formed with openings in the reinforcing bar insertion part of the cylindrical reinforcing bar joint and having an axial interval. And the shaft portion are engaged with each other, and the fastening screw portion is screwed to the female screw portion formed in the screw insertion hole by the tapping blade portion, and is used for both tapping and fastening to the cylindrical reinforcing bar joint. A connection structure between a reinforcing bar joint and a reinforcing bar, wherein a screw is fastened.

The connecting structure between a reinforcing bar joint and a reinforcing bar according to claim 1, wherein a cutting blade part for drilling is formed at a tip part of a shaft part of the tapping / fastening screw.