JP4115616B2

JP4115616B2 - Telescopic ladder

Info

Publication number: JP4115616B2
Application number: JP07134599A
Authority: JP
Inventors: 許弘中尾
Original assignee: 株式会社ナカオ
Priority date: 1999-03-17
Filing date: 1999-03-17
Publication date: 2008-07-09
Anticipated expiration: 2019-03-17
Also published as: JP2000265768A

Description

【０００１】
【発明の属する技術分野】
本発明は、踏桟が所定間隔で配置された柱単位が複数個伸縮可能に連結された伸縮梯子に関する。
【０００２】
【従来の技術】
従来の一般的な３段式の伸縮梯子１００の伸長状態を図１２（Ａ）、（Ｂ）、図１３、及び図１４に示すが、図に示すように、相互に摺動可能に連結された下梯子部１０１、中梯子部１０２及び上梯子部１０３を有している。下梯子部１０１の対向するガイド溝１０４内に中梯子部１０２が摺動可能に移動し、中梯子部１０２のガイド溝１０５内には上梯子部１０３が摺動可能に嵌入している。なお、１０６は下梯子部１０１の踏桟、１０７は中梯子部１０２の踏桟、１０８は上梯子部１０３の踏桟を示し、踏桟１０６〜１０８は両端をリベットによって前記ガイド溝１０４、１０５が形成された柱部材１０９〜１１２及び柱部材１１３、１１４にそれぞれ固定されている。
そして、下梯子部１０１内に収納した中梯子部１０２を上昇させるために、下梯子部１０１の上部にロープ１１５の一端が固着され、このロープ１１５は中梯子１０２の下部及び下梯子部１０１の上部に設けられた滑車１１６、１１６ａを介して下方まで垂下している。また、上梯子部１０３を上昇させるために、別のロープ１１７が中梯子部１０２の上部に固着され、このロープ１１７は上梯子部１０３の下部及び中梯子部１０２の上部に取付けられた滑車１１８、１１８ａを介して下方に垂下している。なお、上昇させた中梯子部１０２及び上梯子部１０３が滑り落ちないように、図示しないストッパー部及びこれを解除する機構が設けられている。
この伸縮梯子１００は下梯子部１０１及び中梯子部１０２を構成する対向する柱部材１０９〜１１２が断面溝形であって、この溝内を上位にある梯子部が摺動移動するようになっているが、図１５（Ａ）、（Ｂ）に示すように、下梯子部１２０、中梯子１２１、上梯子１２２の両側柱にフランジ端部を内側に屈曲させた略Ｈ形の柱部材１２３〜１２８を使用すると共に、中梯子部１２１及び上梯子部１２２に下側の梯子部を摺動移動するガイド部材１２９〜１３６を取付けて構成される伸縮梯子１３８もある。
【０００３】
【発明が解決しようとする課題】
しかしながら、従来例に係る伸縮梯子１００、１３８においては、以下のような問題がある。
（１）伸縮梯子１００の各梯子部の摺動部分は、その移動を滑らかにし、更に製作上の寸法誤差を考慮して、多少のガタを設けて設計している。即ち、下梯子部１０１のガイド溝１０４に対して中梯子部１０２が隙間を有して摺動自在に移動し、中梯子部１０２のガイド溝１０５に対して上梯子部１０３が隙間を有して摺動自在に装着されている。摺動部分にこのような隙間があっても、伸縮梯子１００は対象物に対して斜めに立てかけて使用されるので、下位の梯子部と上位の梯子部の重合部分１３９、１４０では、図１３、図１４に示されるように、下位のガイド溝１０４（１０５）内で上位の梯子部が位置を変えて上下に片当たりし（即ち、面と点で受ける）、これによって梯子面に対する垂直方向の荷重に対しては問題なく使用できる。ところが、梯子面に対して幅方向の隙間Ｃに対しては、ガタを規制する対応がないので、各踏桟１０６〜１０８に対して偏荷重が掛かった場合、上位の梯子部に隙間Ｃ分だけ傾きが生じる。特に、人が梯子を使用する場合には、片足ずつ交互に上位置又は下位置の踏桟を踏むので、伸縮梯子の上下の支持が悪い場合には左右に梯子が揺れて危険であるという問題がある。
このような問題は、伸縮梯子１３８においても、梯子面方向に隙間を形成しているので、同様に生じる問題である。
【０００４】
（２）伸縮梯子１００においてはその伸縮構造が入れ子式であり、伸縮梯子１３８においては外側ガイド取付け式であって上位の梯子部ほど幅狭に作っているので、下位の梯子部ほど強度がアップしている。ところが、伸縮梯子１００、１３８は斜めに立てかけて使用するので、曲げモーメントは両端自由支持の梁と同様な応力分布となって、中梯子部１０２が最大の曲げ応力を受けることになる。従って、中梯子部１０２を適正な部材で構成した場合、下梯子部１０１が過剰品質となって、重量が重くなるという問題がある。
（３）特に、伸縮梯子１００においては、図１３、図１４に示すように、下梯子部１０１の踏桟１０６と中梯子部１０２の踏桟１０７との隙間が狭いので、梯子を伸ばすときあるいは縮めるときにこの部分に指が入ると危険である。また、下梯子部１０１及び中梯子部１０２においては、対向する柱部材１０９〜１１２の連結は、それぞれのフランジ部分に踏桟１０６、１０７を固定しているので、荷重がかかった場合のヒネリが大きいという問題がある。
また、内側にガイド溝が形成されている下位の柱部材とその内側に装着される上位の柱部材との間隔が小さいので、下位の柱部材を物にぶっつけた場合には、スライド不能になる可能性が高い。
【０００５】
（４）一方、伸縮梯子１３８においては、縮める場合、各梯子部１２０〜１２２を重ねるようにして収納するので、収納厚みが大きくなるという問題があり、更には上位の梯子部の踏桟は幅狭（又は、下端幅が広くなる）になるので、使用しにくいという問題がある。
また、各柱部材１２３〜１２８のフランジが外部に出ており、この部分が摺動面を構成するが、フランジ部に物を当てた場合には、その部分が変形してスライド不能という問題が発生する。
（５）次に、従来の伸縮梯子１００、１３８においては、ロープの操作が面倒であるという問題がある。即ち、図１２に示すように、伸縮梯子１００においては、２本のロープ１１５、１１７が地面まで垂れ下がっているが、上位の梯子部を引き上げるとき何れのロープを引っ張ればよいか、個々の動作ごとに確認しながら行う必要がある。
また、伸縮梯子１００を伸ばしたときには、ロープ１１５、１１７が踏桟１０６、１０７上に垂れ下がっており昇降しずらい。
更には、地面にたれ流しになったロープを梯子の調整を行うときや伸縮するときに踏み付ける恐れがある。
本発明はかかる事情に鑑みてなされたもので、材料の使用に無駄がなくて軽量に伸縮梯子を構成でき、しかも使用の揺れを解消できて丈夫な伸縮梯子を提供することを第１の目的とする。
また、ロープの弛みがなく、作業の邪魔にならない伸縮梯子を提供することを第２の目的とする。
【０００６】
【課題を解決するための手段】
前記目的に沿う第１の発明に係る伸縮梯子は、それぞれ溝形部材からなる柱部材を使用した下梯子部、中梯子部及び上梯子部を摺動可能に連結すると共に所定位置でこれらを固定できるストッパーを有した伸縮梯子において、
前記中梯子部の柱部材のウエブ長を前記下梯子部及び前記上梯子部の柱部材のウエブ長より大きくして、前記中梯子部の断面係数を、前記下梯子部及び前記上梯子部の断面係数より大きくし、
しかも、前記下梯子部と前記中梯子部の各摺動部分、及び前記中梯子部と前記上梯子部の各摺動部分には、摺動面が左右対称に斜めとなって、該伸縮梯子を斜めに立てかけて使用する場合に当接する傾斜面を有する斜め摺動機構が設けられ、梯子面に対して垂直方向の荷重が摺動移動する部材の梯子面に対して横方向の移動を拘束し、
前記中梯子部の柱部材内に前記上梯子部の柱部材を摺動可能に配置すると共に、前記下梯子部の上部位置に少しの隙間を有して２つの下向きガイドホルダーを設け、該２つの下向きガイドホルダーに前記中梯子部の柱部材を摺動可能に挿通し、
更に、前記中梯子部の片側の柱部材の上部及び下部に第１及び第２の滑車を設けると共に、前記第１、第２の滑車に張った状態で掛け渡されたロープＡの両端部を対応する側の前記上梯子部の柱部材に固定し、更に前記第１、第２の滑車に掛け渡されたロープＡを前記中梯子部の外側に露出させた。
これによって、中梯子部に比較して曲げモーメントが小さい下梯子部及び上梯子部の部材を節約できる。
また、第１の発明に係る伸縮梯子において、前記中梯子部の柱部材内に前記上梯子部の柱部材を摺動可能に配置すると共に、前記下梯子部の上部位置に少しの隙間を有して２つの下向きガイドホルダーを設け、該２つの下向きガイドホルダーに前記中梯子部の柱部材を摺動可能に挿通しているので、下梯子部の柱部材の大きさが自由となり、中梯子部より小さい断面係数の小さい部材を使用できる。
【０００７】
第１の発明に係る伸縮梯子においては、前記下梯子部と前記中梯子部の各摺動部分、及び前記中梯子部と前記上梯子部の各摺動部分には、摺動面が左右対称に斜めになった斜め摺動機構が設けられ、梯子面に対して垂直方向の荷重が摺動移動する部材の梯子面に対して横方向の移動を拘束しているので、踏桟に偏荷重が掛かっても中梯子部又は上梯子部が揺れない。
ここで、前記摺動面には、滑り性を確保するコーティング材が貼着、又は滑り性を確保する表面処理がなされているのが好ましく、これによって同種金属が滑り合う場合に発生する金属の噛み込みや異常摩耗がなくなる。
【０００８】
第１の発明に係る伸縮梯子において、前記中梯子部の片側の柱部材の上部及び下部に第１及び第２の滑車を設けると共に、前記第１、第２の滑車に張った状態で掛け渡されたロープＡの両端部を対応する側の前記上梯子部の柱部材に固定し、更に前記第１、第２の滑車に掛け渡されたロープＡを前記中梯子部の外側に露出させることも可能である。これによって、ロープの弛みがなくなる。また、ロープは中梯子部に取付けられているので、必ず上梯子部を先に上昇させてから、中梯子部を上げる操作が必要となる。
【０００９】
第１の発明に係る伸縮梯子において、前記中梯子部の下部の一方の柱部材に第３、第４の滑車を、該中梯子部の下部の他方の柱部材に第５、第６の滑車を設けると共に、前記下梯子部の他方の柱部材の上部及び下部に第７、第８の滑車を設け、一端が前記下梯子部の一方の柱部材の下部に固定されたロープＢを、前記第３の滑車、第５の滑車、第８の滑車、第７の滑車、第６の滑車、第４の滑車に順次掛け渡して該ロープＢの他端を前記下梯子部の一方の柱部材の上部に固定し、しかも、前記第７、第８の滑車を通るロープＢは外部に露出させることも可能である。これによって、ロープの撓みが無くなる。
【００１０】
【発明の実施の形態】
続いて、添付した図面を参照しつつ、本発明を具体化した実施の形態につき説明し、本発明の理解に供する。
ここに、図１は本発明の第１の実施の形態に係る伸縮梯子を示す図面であって、（Ａ）は伸ばした状態の伸縮梯子の側面図、（Ｂ）は同正面図、（Ｃ）は縮めた状態の伸縮梯子の側面図、図２は図１における矢視Ｃ−Ｃ断面図、図３は図１における矢視Ｄ−Ｄ断面図、図４は図１における矢視Ｅ−Ｅ断面図、図５は図１における矢視Ｆ−Ｆ断面図、図６は図１における矢視Ｇ−Ｇ断面図、図７、図８は同伸縮梯子の部分斜視図、図９は本発明の第２の実施の形態に係る伸縮梯子の図面であって、（Ａ）は伸ばした状態の伸縮梯子の側面図、（Ｂ）は同正面図、（Ｃ）は縮めた状態の伸縮梯子の側面図、図１０は図９におけるＪ−Ｊ断面図図１１は図９におけるＫ−Ｋ断面図である。
【００１１】
図１〜図８に示すように、本発明の第１の実施の形態に係る伸縮梯子１０は、主として軽量なアルミ材、場合によってＦＲＰを用いて全体が構成され、下梯子部１１と、これに連結される中梯子部１２と、中梯子部１２に連結される上梯子部１３とを有している。以下、これらについて詳しく説明する。
下梯子部１１は、図１、図４、図５に示すように、対向する柱部材１４、１５とこれらを連結する複数のパイプ状部材からなる踏桟１６とを有し、柱部材１４、１５の下端には脚座１７、１８が設けられている。
図４、図５に示すように、柱部材１４、１５はそれぞれ中央のウエブ１９、２０と両側にフランジ２１〜２４とを有する溝形形状となって、踏桟１６の両端部のウエブ１９、２０にそれぞれねじ、リベットかしめ、鍔出し成形かしめ等で固着されている。フランジ２１〜２４の断面は、中央に窪み２５（リベットの頭がこの部分を挿通する）を有する外側に縮幅する台形状となって、その両側に傾斜面２６、２７をそれぞれ備えている。この柱部材１４、１５の上部位置には、図１に示すように、少しの間隔を有して下向きガイドホルダー２８、２９が設けられている。
【００１２】
下向きガイドホルダー２８、２９は、それぞれ対向するガイド板片３０〜３３からなって、ガイド板片３０〜３３の基部は柱部材１４、１５のウエブ１９、２０に固着されている。対向するガイド板片３０、３１と、対向するガイド板片３２、３３は、それぞれ中間部、先部が対向状態で略コ字状に曲げられて、その内側に中梯子部１２が摺動自在に嵌入する空間部を形成している。この空間部の４隅に相当するガイド板片３０〜３３の先部の折り曲げ部分の角には、傾斜加工がなされて内側に約４５度の傾斜面３４〜３７が設けられている。
前記中梯子部１２は、図２〜図５に示すように、前記した下向きガイドホルダー２８、２９の内側に嵌入する柱部材３８、３９とこれを連結する複数の踏桟４０とを有している。柱部材３８、３９は断面が同一の複溝形状となって、ウエブ４１とその両側に連結されるフランジ４２、４３とを有し、更にフランジ４２の外側には更に踏桟４０の両端部が嵌入してリベット４４によって固定する取付け溝４５がそれぞれ形成されている。
ウエブ４１とフランジ４２、４３の連結部分の内側にはそれぞれ傾斜面４６、４７を有し、その外側にもこれに対応する傾斜面４８、４９を有している。なお、柱部材３８、３９の傾斜面４８、４９は、前記した下向きガイドホルダー２８、２９の傾斜面３４、３５と同一の角度となっている。
そして、柱部材３８、３９のそれぞれの取付け溝４５を形成する外側フランジ５０の内側端部は外側に突出する突出部５１を有し、この突出部５１には、前記した下梯子部１１の柱部材１４、１５に形成されたフランジ２２、２４の傾斜面２７に対応する傾斜面５２が形成されている。
【００１３】
従って、中梯子部１２は、下梯子部１１の上部に設けられた下向きガイドホルダー２８、２９と下梯子部１１本体によって形成される空間部に摺動自在に嵌入するが、下向きガイドホルダー２８、２９と下梯子部１１が摺動する部分は、下向きガイドホルダー２８、２９の傾斜面３４〜３７と、柱部材３８、３９の傾斜面４９とであり、下梯子部１１と中梯子部１２が摺動する部分は、柱部材１４、１５の傾斜面２７と、柱部材３８、３９の傾斜面５２とである。この場合、中梯子部１２は、下向きガイドホルダー２８、２９と下梯子部１１によって形成される空間部に十分な隙間（片側、約１．５ｍｍ程度）を有して装入されて、下梯子部１１に対して中梯子部１２が摺動自在に移動することになるが、この伸縮梯子１０は傾斜配置して使用されるので、下梯子部１１と中梯子部１２の重合部分５３の上下では相互に接することになる。この場合、図４、図５に示すように、重合部分５３の上端では傾斜面５２と傾斜面２７が接し、下端では傾斜面３６、３７と傾斜面４９とが接している。これらの対となる傾斜面５２、２７、傾斜面３６、４９、及び傾斜面３７、４９の組み合わせによって、中梯子部１２の揺れを防止する斜め摺動機構が構成されている。これによって、下梯子部１１に対して中梯子部１２は前後方向だけでなく、左右方向も拘束されるので、揺れが生じないという利点がある。なお、各傾斜面を含む摺動部分の何れか一方にはそれぞれ裏面に接着剤が塗布されたコーティング材の一例であるポリ・テトラ・フルオロ・エチレン(-CF₂-CF₂-)_nのテープ５４が貼着されて、この部分の滑りを良くしている。そして、中梯子部１２の柱部材３８、３９の背面側は補強部材５３ａで連結されている。
また、中梯子部１２の柱部材３８、３９のウエブ４１は、下梯子部１１のウエブ１９、２０より十分大きくなって、柱部材３８、３９の断面係数が、柱部材１４、１５の断面係数より十分大きくなっている。これは、伸縮梯子１０を立てかけて使用する場合には、両端自由支持の梁となって、中梯子部１２に最大の曲げモーメントがかかるので、この部分が最大の断面係数を持つ必要があるからである。一方、下梯子部１１は中梯子部１２の上に載って摺動移動するので、その大きさを自由に設計でき、従って、下梯子部１１が必要とする部材の断面係数を有すれば良いので、従来の伸縮梯子より部材を落とすことができ、これによって実際に伸縮梯子にかかる曲げモーメントを考慮した経済設計ができる。
【００１４】
次に、図２、図３を参照しながら、上梯子部１３について説明する。
上梯子部１３は対向する柱部材５５、５６と、これを連結する複数の踏桟５７とを有している。柱部材５５、５６はウエブ５８及びこれに連接するフランジ５９、６０を有する溝形部材からなっており、それぞれのフランジ５９、６０が外方を向いた形で組み付けられて、それぞれのフランジ５９、６０の外側角部には、傾斜面６１、６２が設けられている。なお、この柱部材５５、５６の断面形状は、前記した柱部材１４、１５と同一となっている。従って、上梯子部１３を伸ばして壁等にこの伸縮梯子１０を立てかけた場合には、図１に示す重合部分６３の上部で、両側の傾斜面６１と、柱部材３８、３９の傾斜面４６とが当接し（図２参照）、重合部分６３の下部で柱部材５５、５６の傾斜面６２が、柱部材３８、３９の傾斜面４７に当接し（図３参照）、これによって、上梯子部１３は中梯子部１２に対して梯子面の垂直方向に対してだけでなく、横方向にも規制される。なお、傾斜面６１、６２の下端（外側）に連接する平面と傾斜面４６、４７の下端（外側）に連接する平面の間には隙間Ｇ（図６参照）が形成されて、確実に傾斜面４６、４７と傾斜面６１、６２が当接するようになっている。以上の傾斜面４６、４７と傾斜面６１、６２によって上梯子部１３の横揺れを防止する斜め摺動機構が構成されている。
従って、この伸縮梯子１０の中梯子部１２及び上梯子部１３を伸長して使用する場合に、仮に踏桟４０、５７に偏心荷重が掛かっても傾かないことになる。
なお、各柱部材の内側には、柱部材の強度が不足する場合に、図示するように適当な補強片を設けることも可能である。図５に示すように、柱部材３８、３９の踏桟４０のない部分に、下梯子部１１の柱部材１４、１５の内側をガイドするガイド片１２ａを設けることも可能である。図６は収納した状態の伸縮梯子１０の部分断面であるが、摩擦軽減用のテープ５４は省略されて記載している。
なお、符号１６ａは、取っ手である。
【００１５】
続いて、図７、図８を参照しながら、上梯子部１３及び中梯子部１２を上昇させるロープ機構について説明する。
図７に示すように、中梯子部１２の片側の柱部材３８の溝の上下には、第１の滑車６４と第２の滑車６５が設けられている。第１、第２の滑車６４、６５はそれぞれの車輪が溝内に立った状態で取付けられ、第１、第２の滑車６４、６５に張った状態で掛けられたロープ６６の一方が柱部材３８の外側を挿通し、第１、第２の滑車６４、６５に掛かったロープ６６の他方は柱部材３８の内側を挿通して、それぞれの端部が上梯子部１３の下部に取付けられた止金６７に固定されている。このような構造とすることによって、外側に張られたロープ６６を上げ下げすることによって、上梯子部１３の昇降が行える。第１、第２の滑車６４、６５はその車輪が外部に露出するのを防止するカバーを備えている。なお、上梯子部１３の落下を防止する、すなわち上梯子部１３を伸ばした状態で固定できる周知構造のストッパー６８が上梯子部１３の下部に設けられている。このストッパー６８は下部に掛止用の切欠き６９を有し、スプリングによってこの切欠き６９が踏桟４０方向に付勢されている。
【００１６】
図８に示すように、中梯子部１２の下部の一方の柱部材３９に重合してそれぞれが独立に回転する第３、第４の滑車７０、７１を設け、中梯子部１２の下部の他方の柱部材３８にそれぞれ独立に回転する第５、第６の滑車７２、７３を設けると共に、下梯子部１１の柱部材１４の上部及び下部に第７、第８の滑車７４、７５を設ける。そして、一端が下梯子部１１の柱部材１５の下部に固定されたロープ７６を、第３の滑車７０、第５の滑車７２、第８の滑車７５、第７の滑車７４、第６の滑車７３、第４の滑車７１に順次掛け渡してロープ７６の他端を下梯子部１１の柱部材１５の上部に固定する。そして、第７、第８の滑車７４、７５の軸は梯子面に直交する方向に配置されて、第７、第８の滑車７４、７５を通るロープ７６は外部に露出させている。従って、このロープ７６を操作することによって、中梯子部１２が昇降する。
ここで、中梯子部１２の下部には上昇させた中梯子部１２の落下を防止する、すなわち中梯子部１２を伸ばした状態で固定できる周知構造のストッパー７７が設けられている。なお、第７、第８の滑車７４、７５には車輪の露出を防止するカバーが設けられている。
【００１７】
続いて、図９〜図１１を参照しながら、本発明の第２の実施の形態に係る伸縮梯子７９について説明するが、前記した第１の実施の形態に係る伸縮梯子１０と同一の構成要素については同一の番号を付してその詳しい説明を省略する。
第２の実施の形態に係る伸縮梯子７９と第１の実施の形態に係る伸縮梯子１０の異なる点は、第１の実施の形態に係る伸縮梯子１０においては、下梯子部１１の上部に少しの距離を置いて下向きガイドホルダー２８、２９が設けられて、これによって、中梯子部１２をガイドしているが、第２の実施の形態に係る伸縮梯子７９においては、図９（Ａ）、（Ｂ）、（Ｃ）に示すように、下梯子部１１の上部に下向きガイドホルダー２８を配置し、中梯子部１２の下部に上向きガイドホルダー８０を配置した点である。
従って、図９におけるＪ−Ｊの主要断面は、図１０に示すように図４と同一となる。一方、図１１に示すように、中梯子部１２の下部に上向きガイドホルダー８０は設けている。この上向きガイドホルダー８０は、対向するガイド板片８１、８２からなって、ガイド板片８１、８２の基部は、中梯子部１２の柱部材３８、３９のウエブ４１に固着されている。対向するガイド板片８１、８２は、それぞれ中間部、先部が対向状態で略コ字状に曲げられて、その内側に下梯子部１１が摺動自在に嵌入する空間部を形成している。ガイド板片８１、８２の上側角部は斜めに折り曲げられて内側に４５度の傾斜面８３、８４が形成されている。
【００１８】
前記傾斜面８３、８４は柱部材１９、２０の斜め角部に形成されている傾斜面２６が摺動移動するようになっている。そして、柱部材１９、２０の反対側のフランジ２２、２４の内側に形成されている傾斜面２７には、それぞれ中梯子部１２の柱部材３８、３９の外側フランジ５０の端部に形成されている傾斜面５２が摺動可能に当接するようになっている。このように、下梯子部１１と中梯子部１２との上下の摺動部分を傾斜面（４５度）によって当接、摺動させているので、伸縮梯子１０が斜めに立てかけられた場合の梯子面に対する垂直方向の荷重によって梯子自体の横方向の揺れも拘束できる構造となっている。
【００１９】
各傾斜面の角度は前記実施の形態においては、約４５度であったが、３０〜６０度の範囲で変更することもできる。
【００２０】
【発明の効果】
請求項１〜３記載の伸縮梯子は、以上の説明からも明らかなように、下梯子部、中梯子部及び上梯子部を有する伸縮梯子において、中梯子部の柱部材のウエブ長を下梯子部及び上梯子部の柱部材のウエブ長より大きくして、中梯子部の断面係数を、下梯子部及び上梯子部の断面係数より大きくしたので、下梯子部の過剰品質を防止し、軽量な伸縮梯子を安価に提供できる。
そして、下梯子部と中梯子部の各摺動部分、及び中梯子部と上梯子部の各摺動部分には、摺動面が左右対称に斜めになった斜め摺動機構が設けられ、梯子面に対して垂直方向の荷重が摺動移動する部材の梯子面に対して横方向の移動を拘束したので、中梯子部や上梯子部の踏桟に偏荷重が掛かっても、中梯子部や上梯子部の揺れが無くなった。
そして、中梯子部の柱部材内に上梯子部の柱部材を摺動可能に配置すると共に、下梯子部の上部位置に少しの隙間を有して２つの下向きガイドホルダーを設け、２つの下向きガイドホルダーに中梯子部の柱部材を摺動可能に挿通したので、縮めた状態の伸縮梯子の厚みが薄くなり、コンパクトに収納できる。
請求項２記載の伸縮梯子においては、中梯子部の片側の柱部材の上部及び下部に第１及び第２の滑車を設けると共に、第１、第２の滑車に張った状態で掛け渡されたロープＡの両端部を対応する側の上梯子部の柱部材に固定し、更に第１、第２の滑車に掛け渡されたロープＡを中梯子部の外側に露出させたので、上梯子部を昇降する場合のロープＡに弛みが発生せず、更には、このロープＡは中梯子部に取付けてあるので、中梯子部を上昇させた後は操作ができず、操作の確実性が保証できることになった。
請求項３記載の伸縮梯子においては、中梯子部の下部の一方の柱部材に第３、第４の滑車を、該中梯子部の下部の他方の柱部材に第５、第６の滑車を設けると共に、下梯子部の他方の柱部材の上部及び下部に第７、第８の滑車を設け、一端が下梯子部の一方の柱部材の下部に固定されたロープＢを、第３の滑車、第５の滑車、第８の滑車、第７の滑車、第６の滑車、第４の滑車に順次掛け渡して該ロープＢの他端を下梯子部の一方の柱部材の上部に固定し、しかも、第７、第８の滑車を通るロープＢは外部に露出させたので、中梯子部を昇降するロープＢに弛みが発生せず、従って、従来のようにロープが散らかることがなく、作業の邪魔にならない。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る伸縮梯子を示す図面であって、（Ａ）は伸ばした状態の伸縮梯子の側面図、（Ｂ）は同正面図、（Ｃ）は縮めた状態の伸縮梯子の側面図である。
【図２】図１における矢視Ｃ−Ｃ断面図である。
【図３】図１における矢視Ｄ−Ｄ断面図である。
【図４】図１における矢視Ｅ−Ｅ断面図である。
【図５】図１における矢視Ｆ−Ｆ断面図である。
【図６】図１における矢視Ｇ−Ｇ断面図である。
【図７】同伸縮梯子の部分斜視図である。
【図８】同伸縮梯子の部分斜視図である。
【図９】本発明の第２の実施の形態に係る伸縮梯子の図面であって、（Ａ）は伸ばした状態の伸縮梯子の側面図、（Ｂ）は同正面図、（Ｃ）は縮めた状態の伸縮梯子の側面図である。
【図１０】図９における矢視Ｊ−Ｊ断面図である。
【図１１】図９における矢視Ｋ−Ｋ断面図である。
【図１２】従来例に係る伸縮梯子の図面であって、（Ａ）は伸ばした状態の伸縮梯子の側面図、（Ｂ）は同正面図である。
【図１３】図１２におけるＡ−Ａ断面図である。
【図１４】図１２における矢視Ｂ−Ｂ断面図である。
【図１５】従来例に係る伸縮梯子の図面であって、（Ａ）は屈曲させた略Ｈ形の柱部材を示す図であり、（Ｂ）伸縮梯子の正面図である。
【符号の説明】
１０：伸縮梯子、１１：下梯子部、１２：中梯子部、１２ａ：ガイド片、１３：上梯子部、１４、１５：柱部材、１６：踏桟、１６ａ：取っ手、１７、１８：脚座、１９、２０：ウエブ、２１〜２４：フランジ、２５：窪み、２６、２７：傾斜面、２８、２９：下向きガイドホルダー、３０〜３３：ガイド板片、３４〜３７：傾斜面、３８、３９：柱部材、４０：踏桟、４１：ウエブ、４２、４３：フランジ、４４：リベット、４５：取付け溝、４６〜４９：傾斜面、５０：外側フランジ、５１：突出部、５２：傾斜面、５３：重合部分、５４：テープ、５５、５６：柱部材、５７：踏桟、５８：ウエブ、５９、６０：フランジ、６１、６２：傾斜面、６３：重合部分、６４：第１の滑車、６５：第２の滑車、６６：ロープ、６７：止金、６８：ストッパー、６９：切欠き、７０：第３の滑車、７１：第４の滑車、７２：第５の滑車、７３：第６の滑車、７４：第７の滑車、７５：第８の滑車、７６：ロープ、７７：ストッパー、７９：伸縮梯子、８０：上向きガイドホルダー、８１、８２：ガイド板片、８３、８４：傾斜面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a telescopic ladder in which a plurality of column units each having stepped bars arranged at predetermined intervals are connected to be extendable and contractible.
[0002]
[Prior art]
12 (A), (B), FIG. 13 and FIG. 14 show the extended state of a conventional general three-stage telescopic ladder 100, which are slidably connected to each other as shown in the figure. The lower ladder portion 101, the middle ladder portion 102, and the upper ladder portion 103 are provided. The middle ladder portion 102 is slidably moved in the guide groove 104 facing the lower ladder portion 101, and the upper ladder portion 103 is slidably fitted in the guide groove 105 of the middle ladder portion 102. Reference numeral 106 denotes a step rail of the lower ladder portion 101, 107 denotes a step rail of the middle ladder portion 102, 108 denotes a step rail of the upper ladder portion 103, and the step rails 106 to 108 have the guide grooves 104, 105 by rivets at both ends. Are fixed to the column members 109 to 112 and the column members 113 and 114, respectively.
In order to raise the middle ladder portion 102 stored in the lower ladder portion 101, one end of a rope 115 is fixed to the upper portion of the lower ladder portion 101, and the rope 115 is attached to the lower portion of the middle ladder 102 and the lower ladder portion 101. It hangs down through pulleys 116 and 116a provided at the top. In order to raise the upper ladder portion 103, another rope 117 is fixed to the upper portion of the middle ladder portion 102, and this rope 117 is attached to the lower portion of the upper ladder portion 103 and the pulley 118 attached to the upper portion of the middle ladder portion 102. , 118a. A stopper portion (not shown) and a mechanism for releasing the stopper portion are provided so that the raised middle ladder portion 102 and upper ladder portion 103 do not slide down.
In this telescopic ladder 100, the opposing pillar members 109 to 112 constituting the lower ladder portion 101 and the middle ladder portion 102 have a cross-sectional groove shape, and the upper ladder portion slides and moves in the groove. However, as shown in FIGS. 15A and 15B, substantially H-shaped column members 123-3 having flange ends bent inwardly on both side columns of the lower ladder portion 120, the middle ladder 121, and the upper ladder 122, respectively. There is also a telescopic ladder 138 configured by using 128 and attaching guide members 129 to 136 that slide and move the lower ladder portion to the middle ladder portion 121 and the upper ladder portion 122.
[0003]
[Problems to be solved by the invention]
However, the telescopic ladders 100 and 138 according to the conventional example have the following problems.
(1) The sliding portion of each ladder portion of the extendable ladder 100 is designed with smooth movement and a slight backlash in consideration of manufacturing dimensional errors. That is, the middle ladder portion 102 moves slidably with a gap with respect to the guide groove 104 of the lower ladder portion 101, and the upper ladder portion 103 has a gap with respect to the guide groove 105 of the middle ladder portion 102. And is slidably mounted. Even if there is such a gap in the sliding portion, the telescopic ladder 100 is used while standing obliquely with respect to the object. Therefore, in the overlapping portions 139 and 140 of the lower ladder portion and the upper ladder portion, FIG. As shown in FIG. 14, the upper ladder portion changes position within the lower guide groove 104 (105) so that it vertically touches (i.e., receives at the surface and the point), and thereby the direction perpendicular to the ladder surface. It can be used without problems for loads of. However, since the gap C in the width direction with respect to the ladder surface does not correspond to the backlash control, when an uneven load is applied to each of the steps 106 to 108, the gap C is added to the upper ladder portion. Only tilt occurs. In particular, when a person uses a ladder, the legs are stepped on the upper and lower steps alternately one foot at a time, so if the upper and lower support of the telescopic ladder is poor, it is dangerous to swing the ladder from side to side There is.
Such a problem also occurs in the telescopic ladder 138 because a gap is formed in the ladder surface direction.
[0004]
(2) The telescopic ladder 100 has a telescopic structure, and the telescopic ladder 138 is an outer guide mounting type. The upper ladder part is made narrower, so the lower ladder part is stronger. is doing. However, since the telescopic ladders 100 and 138 are used obliquely, the bending moment has a stress distribution similar to that of a beam that is freely supported at both ends, and the middle ladder portion 102 receives the maximum bending stress. Therefore, when the middle ladder portion 102 is formed of an appropriate member, there is a problem that the lower ladder portion 101 becomes excessive quality and the weight increases.
(3) Particularly, in the telescopic ladder 100, as shown in FIGS. 13 and 14, the gap between the step rail 106 of the lower ladder portion 101 and the step rail 107 of the middle ladder portion 102 is narrow. It is dangerous if a finger enters this part when shrinking. Further, in the lower ladder portion 101 and the middle ladder portion 102, the column members 109 to 112 facing each other are fixed to the respective flange portions so that the crosspieces 106 and 107 are fixed. There is a problem of being big.
In addition, since the interval between the lower column member in which the guide groove is formed on the inner side and the upper column member mounted on the inner side is small, it is impossible to slide when the lower column member is hit against an object. Probability is high.
[0005]
(4) On the other hand, when the telescopic ladder 138 is contracted, the ladder sections 120 to 122 are stored so as to overlap each other, so that there is a problem that the storage thickness becomes large. Since it becomes narrow (or the lower end width becomes wide), there is a problem that it is difficult to use.
Moreover, the flange of each pillar member 123-128 has come out and this part comprises a sliding surface, but when an object is applied to a flange part, the problem that the part deform | transforms and cannot slide. appear.
(5) Next, the conventional telescopic ladders 100 and 138 have a problem that the operation of the rope is troublesome. In other words, as shown in FIG. 12, in the telescopic ladder 100, the two ropes 115 and 117 hang down to the ground, but which rope should be pulled when pulling up the upper ladder, for each individual operation. It is necessary to check while checking.
Further, when the telescopic ladder 100 is extended, the ropes 115 and 117 hang down on the crosspieces 106 and 107 and are difficult to move up and down.
Furthermore, there is a risk of stepping on a rope that has drifted down to the ground when the ladder is adjusted or expanded or contracted.
The present invention has been made in view of such circumstances, and a first object of the present invention is to provide a tough extensible ladder that can be used to make a telescopic ladder lightly without using material, and that can eliminate the shaking of use. And
It is a second object of the present invention to provide a telescopic ladder that does not sag the rope and does not obstruct work.
[0006]
[Means for Solving the Problems]
The telescopic ladder according to the first invention in accordance with the above object slidably connects the lower ladder section, the middle ladder section, and the upper ladder section each using a column member made of a groove-shaped member, and fixes them at predetermined positions. In a telescopic ladder with a stopper that can
The web length of the pillar member of the middle ladder portion is made larger than the web length of the pillar member of the lower ladder portion and the upper ladder portion, and the section modulus of the middle ladder portion is determined by the lower ladder portion and the upper ladder portion. Larger than the section modulus,
In addition, the sliding surfaces of the lower ladder portion and the middle ladder portion and the sliding portions of the middle ladder portion and the upper ladder portion are obliquely symmetrical in the left-right direction.WhenBecomeAnd having an inclined surface that comes into contact when the telescopic ladder is used obliquelyAn oblique sliding mechanism is provided, and the movement in the direction perpendicular to the ladder surface is constrained from moving laterally with respect to the ladder surface of the member that slides and moves.And
The pillar member of the upper ladder part is slidably disposed in the pillar member of the middle ladder part, and two downward guide holders are provided with a slight gap at the upper position of the lower ladder part. The pillar member of the middle ladder part is slidably inserted into two downward guide holders,
Furthermore, the first and second pulleys are provided on the upper and lower portions of the pillar member on one side of the middle ladder portion, and both ends of the rope A that is stretched over the first and second pulleys are provided. Fixed to the pillar member of the upper ladder portion on the corresponding side, and further, the rope A hung around the first and second pulleys was exposed to the outside of the middle ladder portion..
Thereby, it is possible to save the members of the lower ladder portion and the upper ladder portion whose bending moment is smaller than that of the middle ladder portion.
Further, in the telescopic ladder according to the first invention, the pillar member of the upper ladder part is slidably disposed in the pillar member of the middle ladder part, and a small gap is provided at an upper position of the lower ladder part. Two downward guide holders are provided, and the pillar members of the middle ladder portion are slidably inserted into the two downward guide holders.BecauseThe size of the pillar member of the lower ladder portion is free, and a member having a smaller section modulus than the middle ladder portion can be used.
[0007]
In the telescopic ladder according to the first invention, the sliding surfaces of the sliding portions of the lower ladder portion and the middle ladder portion and the sliding portions of the middle ladder portion and the upper ladder portion are symmetrical. An oblique sliding mechanism is provided at an angle to restrain the movement in the lateral direction with respect to the ladder surface of the member that slides and moves in a direction perpendicular to the ladder surface.BecauseEven if an uneven load is applied to the pedestal, the middle ladder or upper ladder does not shake.
Here, it is preferable that the sliding surface is provided with a coating material that ensures slipperiness, or is subjected to a surface treatment that ensures slipperiness, whereby the metal of the same type is generated when the same type of metal slides. Biting and abnormal wear are eliminated.
[0008]
In the telescopic ladder according to the first invention, the first and second pulleys are provided on the upper and lower portions of the column member on one side of the middle ladder portion, and the stretched ladder is stretched over the first and second pulleys. Fixing both ends of the rope A to the column member of the upper ladder portion on the corresponding side, and further exposing the rope A hung around the first and second pulleys to the outside of the middle ladder portion Is also possible. This eliminates slack in the rope. Further, since the rope is attached to the middle ladder portion, it is necessary to raise the upper ladder portion first and then raise the middle ladder portion.
[0009]
In the telescopic ladder according to the first invention, the third and fourth pulleys are disposed on one column member below the middle ladder portion, and the fifth and sixth pulleys are disposed on the other pillar member below the middle ladder portion. And provided with seventh and eighth pulleys on the upper and lower parts of the other pillar member of the lower ladder part, and the rope B having one end fixed to the lower part of the one pillar member of the lower ladder part, A third pulley, a fifth pulley, an eighth pulley, a seventh pulley, a sixth pulley, a fourth pulley, and the other end of the rope B are sequentially connected to one pillar member of the lower ladder portion. Further, the rope B passing through the seventh and eighth pulleys can be exposed to the outside. This eliminates the bending of the rope.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
FIG. 1 is a drawing showing the telescopic ladder according to the first embodiment of the present invention, wherein (A) is a side view of the telescopic ladder in an extended state, (B) is the front view thereof, and (C) ) Is a side view of the telescopic ladder in a contracted state, FIG. 2 is a cross-sectional view taken along the line CC in FIG. 1, FIG. 3 is a cross-sectional view taken along the line DD in FIG. FIG. 5 is a sectional view taken along line FF in FIG. 1, FIG. 6 is a sectional view taken along line GG in FIG. 1, FIGS. 7 and 8 are partial perspective views of the telescopic ladder, and FIG. It is drawing of the expansion-contraction ladder concerning the 2nd Embodiment of invention, Comprising: (A) is a side view of the expansion-contraction ladder in the extended state, (B) is the same front view, (C) is the expansion-contraction ladder in the contracted state FIG. 10 is a sectional view taken along line JJ in FIG. 9. FIG. 11 is a sectional view taken along line KK in FIG.
[0011]
As shown in FIGS. 1 to 8, the telescopic ladder 10 according to the first embodiment of the present invention is mainly composed of a lightweight aluminum material, and in some cases using FRP. And an upper ladder portion 13 connected to the middle ladder portion 12. These will be described in detail below.
As shown in FIGS. 1, 4, and 5, the lower ladder portion 11 includes opposing pillar members 14 and 15 and a step rail 16 including a plurality of pipe-like members that connect the pillar members 14 and 15. Leg seats 17 and 18 are provided at the lower end of 15.
As shown in FIGS. 4 and 5, the column members 14 and 15 are each formed into a groove shape having the central webs 19 and 20 and the flanges 21 to 24 on both sides, and the webs 19 and 26 at both ends of the footrail 16 are provided. 20 are fixed to each other by screws, rivet caulking, staking molding caulking, or the like. The cross sections of the flanges 21 to 24 have a trapezoidal shape which is reduced in width and has a recess 25 (the rivet head passes through this portion) in the center, and are provided with inclined surfaces 26 and 27 on both sides thereof. As shown in FIG. 1, downward guide holders 28 and 29 are provided at upper positions of the column members 14 and 15 with a slight space therebetween.
[0012]
The downward guide holders 28 and 29 are respectively composed of opposing guide plate pieces 30 to 33, and the base portions of the guide plate pieces 30 to 33 are fixed to the webs 19 and 20 of the column members 14 and 15. The opposing guide plate pieces 30 and 31 and the opposing guide plate pieces 32 and 33 are bent in a substantially U shape with the intermediate portion and the tip portion facing each other, and the middle ladder portion 12 is slidable inside. The space part which fits in is formed. At the corners of the bent portions of the tip portions of the guide plate pieces 30 to 33 corresponding to the four corners of the space portion, the inclined surfaces 34 to 37 of about 45 degrees are provided on the inner side.
As shown in FIGS. 2 to 5, the middle ladder portion 12 includes column members 38 and 39 that are fitted inside the above-described downward guide holders 28 and 29, and a plurality of step bars 40 that connect the column members 38 and 39. Yes. The column members 38 and 39 have a double groove shape with the same cross section, and have a web 41 and flanges 42 and 43 connected to both sides thereof. Mounting grooves 45 that are inserted and fixed by rivets 44 are formed.
The web 41 and the flanges 42 and 43 have inclined surfaces 46 and 47 on the inner side of the connecting portion, respectively, and correspondingly inclined surfaces 48 and 49 on the outer side. The inclined surfaces 48 and 49 of the column members 38 and 39 are at the same angle as the inclined surfaces 34 and 35 of the downward guide holders 28 and 29 described above.
And the inner edge part of the outer side flange 50 which forms each attachment groove | channel 45 of the pillar members 38 and 39 has the protrusion part 51 which protrudes outside, This protrusion part 51 has the pillar of the above-mentioned lower ladder part 11 in this protrusion part 51. An inclined surface 52 corresponding to the inclined surface 27 of the flanges 22 and 24 formed on the members 14 and 15 is formed.
[0013]
Therefore, the middle ladder portion 12 is slidably fitted into the space formed by the downward guide holders 28 and 29 provided on the upper portion of the lower ladder portion 11 and the main body of the lower ladder portion 11, but the downward guide holder 28, 29 and the part where the lower ladder part 11 slides are the inclined surfaces 34 to 37 of the downward guide holders 28 and 29 and the inclined surface 49 of the column members 38 and 39, and the lower ladder part 11 and the middle ladder part 12 are The sliding parts are the inclined surfaces 27 of the column members 14 and 15 and the inclined surfaces 52 of the column members 38 and 39. In this case, the middle ladder portion 12 is inserted into the space formed by the downward guide holders 28 and 29 and the lower ladder portion 11 with a sufficient gap (one side, about 1.5 mm), and the lower ladder is placed. The middle ladder portion 12 is slidably moved with respect to the portion 11, but the telescopic ladder 10 is used in an inclined manner, so that the upper and lower portions of the overlapping portions 53 of the lower ladder portion 11 and the middle ladder portion 12 are used. Then we will touch each other. In this case, as shown in FIGS. 4 and 5, the inclined surface 52 and the inclined surface 27 are in contact with each other at the upper end of the overlapping portion 53, and the inclined surfaces 36 and 37 and the inclined surface 49 are in contact with each other at the lower end. A combination of the inclined surfaces 52 and 27, the inclined surfaces 36 and 49, and the inclined surfaces 37 and 49 that form a pair constitutes an oblique sliding mechanism that prevents the middle ladder portion 12 from shaking. Thereby, since the middle ladder part 12 is restrained not only in the front-rear direction but also in the left-right direction with respect to the lower ladder part 11, there is an advantage that no shaking occurs. One of the sliding parts including each inclined surface is an example of a coating material in which an adhesive is applied to the back surface of polytetrafluoroethylene (-CF₂-CF₂-)_nThe tape 54 is affixed to improve the sliding of this portion. And the back side of the column members 38 and 39 of the middle ladder part 12 is connected by a reinforcing member 53a.
Further, the web 41 of the column members 38 and 39 of the middle ladder portion 12 is sufficiently larger than the webs 19 and 20 of the lower ladder portion 11, and the section modulus of the column members 38 and 39 is the section modulus of the column members 14 and 15. It is getting bigger enough. This is because when the telescopic ladder 10 is used in a standing state, it becomes a beam of free support at both ends, and the maximum bending moment is applied to the middle ladder portion 12, so this portion needs to have the maximum section modulus. It is. On the other hand, since the lower ladder portion 11 slides on the middle ladder portion 12, the size thereof can be freely designed, and therefore the lower ladder portion 11 only needs to have a section modulus of the member required. Therefore, the member can be dropped from the conventional telescopic ladder, and thereby, an economic design can be made in consideration of the bending moment actually applied to the telescopic ladder.
[0014]
Next, the upper ladder part 13 is demonstrated, referring FIG. 2, FIG.
The upper ladder portion 13 has column members 55 and 56 facing each other, and a plurality of step bars 57 for connecting them. Each of the column members 55 and 56 is formed of a groove-shaped member having a web 58 and flanges 59 and 60 connected to the web 58. The flanges 59 and 60 are assembled with the flanges 59 and 60 facing outward. Inclined surfaces 61 and 62 are provided at the outer corners of 60. The cross-sectional shapes of the column members 55 and 56 are the same as those of the column members 14 and 15 described above. Accordingly, when the upper ladder portion 13 is extended and the telescopic ladder 10 is stood against a wall or the like, the inclined surfaces 61 on both sides and the inclined surfaces 46 of the column members 38 and 39 are formed on the upper portion of the overlapping portion 63 shown in FIG. WhenButThe inclined surface 62 of the column members 55 and 56 contacts the inclined surface 47 of the column members 38 and 39 at the lower portion of the overlapped portion 63 (see FIG. 3), thereby the upper ladder portion 13. Is restricted not only in the vertical direction of the ladder surface but also in the lateral direction with respect to the middle ladder portion 12. A gap G (see FIG. 6) is formed between the plane connected to the lower ends (outer sides) of the inclined surfaces 61 and 62 and the plane connected to the lower ends (outer sides) of the inclined surfaces 46 and 47, thereby reliably inclining. The surfaces 46 and 47 and the inclined surfaces 61 and 62 come into contact with each other. The inclined surfaces 46 and 47 and the inclined surfaces 61 and 62 constitute an oblique sliding mechanism that prevents the upper ladder portion 13 from rolling.
Therefore, when the middle ladder portion 12 and the upper ladder portion 13 of the telescopic ladder 10 are extended and used, even if an eccentric load is applied to the crosspieces 40 and 57, they do not tilt.
In addition, when the strength of the column member is insufficient, an appropriate reinforcing piece can be provided inside the column member as illustrated. As shown in FIG. 5, a guide piece 12 a that guides the inside of the pillar members 14 and 15 of the lower ladder portion 11 may be provided in a portion of the pillar members 38 and 39 where the step bar 40 is not provided. FIG. 6 is a partial cross section of the telescopic ladder 10 in the housed state, but the friction reducing tape 54 is omitted.
In addition, the code | symbol 16a is a handle.
[0015]
Subsequently, a rope mechanism for raising the upper ladder portion 13 and the middle ladder portion 12 will be described with reference to FIGS. 7 and 8.
As shown in FIG. 7, a first pulley 64 and a second pulley 65 are provided above and below the groove of the column member 38 on one side of the middle ladder portion 12. The first and second pulleys 64 and 65 are attached with their wheels standing in the grooves, and one of the ropes 66 hung on the first and second pulleys 64 and 65 is a column member. 38, and the other of the ropes 66 hanging on the first and second pulleys 64 and 65 is inserted through the inner side of the column member 38, and the respective end portions are attached to the lower portion of the upper ladder portion 13. It is fixed to a clasp 67. With this structure, the upper ladder portion 13 can be raised and lowered by raising and lowering the rope 66 stretched outside. The first and second pulleys 64 and 65 are provided with a cover for preventing the wheels from being exposed to the outside. A stopper 68 having a known structure that prevents the upper ladder portion 13 from falling, that is, can be fixed with the upper ladder portion 13 extended, is provided at the lower portion of the upper ladder portion 13. This stopper 68 has a notch 69 for latching in the lower part, and this notch 69 is urged | biased by the spring toward the stepping bar 40.
[0016]
As shown in FIG. 8, third and fourth pulleys 70 and 71 that overlap with one column member 39 at the lower portion of the middle ladder portion 12 and rotate independently are provided, and the other lower portion of the middle ladder portion 12 is provided. The column member 38 is provided with fifth and sixth pulleys 72 and 73 that rotate independently of each other, and the seventh and eighth pulleys 74 and 75 are provided above and below the column member 14 of the lower ladder portion 11. Then, the rope 76 having one end fixed to the lower part of the column member 15 of the lower ladder portion 11 is connected to the third pulley 70, the fifth pulley 72, the eighth pulley 75, the seventh pulley 74, and the sixth pulley. 73, and the other end of the rope 76 is fixed to the upper part of the column member 15 of the lower ladder portion 11 by sequentially passing over the fourth pulley 71. The axes of the seventh and eighth pulleys 74 and 75 are arranged in a direction orthogonal to the ladder surface, and the rope 76 passing through the seventh and eighth pulleys 74 and 75 is exposed to the outside. Therefore, by operating this rope 76, the middle ladder portion 12 is raised and lowered.
Here, a stopper 77 having a well-known structure is provided below the middle ladder portion 12 so as to prevent the raised middle ladder portion 12 from dropping, that is, the middle ladder portion 12 can be fixed in an extended state. The seventh and eighth pulleys 74 and 75 are provided with covers that prevent the wheels from being exposed.
[0017]
Subsequently, the telescopic ladder 79 according to the second embodiment of the present invention will be described with reference to FIGS. 9 to 11, and the same components as those of the telescopic ladder 10 according to the first embodiment described above. Are given the same numbers and their detailed explanation is omitted.
The difference between the telescopic ladder 79 according to the second embodiment and the telescopic ladder 10 according to the first embodiment is that, in the telescopic ladder 10 according to the first embodiment, a little on the upper part of the lower ladder portion 11. The downward guide holders 28 and 29 are provided at a distance of, thereby guiding the middle ladder portion 12. In the telescopic ladder 79 according to the second embodiment, FIG. As shown in (B) and (C), a downward guide holder 28 is disposed above the lower ladder portion 11, and an upward guide holder 80 is disposed below the middle ladder portion 12.
9 is the same as FIG. 4 as shown in FIG. On the other hand, as shown in FIG. 11, an upward guide holder 80 is provided below the middle ladder portion 12. The upward guide holder 80 includes guide plate pieces 81 and 82 facing each other, and the base portions of the guide plate pieces 81 and 82 are fixed to the web 41 of the column members 38 and 39 of the middle ladder portion 12. The opposing guide plate pieces 81 and 82 are bent in a substantially U shape with the intermediate portion and the tip portion facing each other, and form a space portion in which the lower ladder portion 11 is slidably fitted. . The upper corners of the guide plate pieces 81 and 82 are bent obliquely to form 45-degree inclined surfaces 83 and 84 on the inner side.
[0018]
The inclined surfaces 83 and 84 are configured such that the inclined surfaces 26 formed at the oblique corners of the column members 19 and 20 slide. The inclined surfaces 27 formed on the inner sides of the flanges 22 and 24 on the opposite side of the column members 19 and 20 are respectively formed at the ends of the outer flanges 50 of the column members 38 and 39 of the middle ladder portion 12. The inclined surface 52 is slidably contacted. In this way, the upper and lower sliding portions of the lower ladder portion 11 and the middle ladder portion 12 are brought into contact with and slided by the inclined surface (45 degrees).soWhen the telescopic ladder 10 is leaned diagonally, it is possible to restrain the lateral shaking of the ladder itself by a load in the vertical direction with respect to the ladder surface.
[0019]
The angle of each inclined surface is about 45 degrees in the above embodiment, but can be changed within a range of 30 to 60 degrees.
[0020]
【The invention's effect】
Claims 1 to3As is apparent from the above description, the telescopic ladder described is a telescopic ladder having a lower ladder part, a middle ladder part, and an upper ladder part. Since the section modulus of the middle ladder part is larger than the section modulus of the lower ladder part and upper ladder part by making it larger than the web length of the column member, it prevents excessive quality of the lower ladder part and makes a lightweight telescopic ladder inexpensive. Can be provided.
And each sliding part of the lower ladder part and the middle ladder part, and each sliding part of the middle ladder part and the upper ladder part is provided with an oblique sliding mechanism in which the sliding surface is obliquely symmetrical. Since the load in the vertical direction relative to the ladder surface restrains the movement in the lateral direction relative to the ladder surface of the sliding member, the middle ladder even if an uneven load is applied to the step ladder of the middle ladder or upper ladder The shaking of the part and the upper ladder part disappeared.
AndThe upper ladder column member is slidably disposed in the middle ladder column member, and two downward guide holders are provided with a slight gap at the upper position of the lower ladder unit. Since the pillar member of the middle ladder portion is slidably inserted in the middle, the thickness of the telescopic ladder in the contracted state is reduced and can be stored compactly.
Claim2In the telescopic ladder described above, the first and second pulleys are provided at the upper and lower portions of the column member on one side of the middle ladder portion, and the rope A stretched over the first and second pulleys. Since both ends are fixed to the pillar members of the corresponding upper ladder part, and the rope A hung around the first and second pulleys is exposed outside the middle ladder part, the upper ladder part is moved up and down. In this case, the rope A does not sag, and since the rope A is attached to the middle ladder portion, the rope A cannot be operated after the middle ladder portion is raised, and the certainty of the operation can be guaranteed. It was.
Claim3In the telescopic ladder described, the third and fourth pulleys are provided on one pillar member at the lower part of the middle ladder part, and the fifth and sixth pulleys are provided on the other pillar member at the lower part of the middle ladder part, Seventh and eighth pulleys are provided above and below the other pillar member of the lower ladder portion, and a rope B having one end fixed to the lower portion of one pillar member of the lower ladder portion is connected to the third pulley, A pulley, an eighth pulley, a seventh pulley, a sixth pulley, a fourth pulley, and the other end of the rope B is fixed to the upper portion of one pillar member of the lower ladder portion, and Since the rope B passing through the seventh and eighth pulleys is exposed to the outside, the rope B that moves up and down the middle ladder portion does not sag, and thus the rope does not clutter as in the prior art, which hinders work. do not become.
[Brief description of the drawings]
FIG. 1 is a drawing showing a telescopic ladder according to a first embodiment of the present invention, wherein (A) is a side view of the telescopic ladder in an extended state, (B) is a front view thereof, and (C) is a front view thereof. It is a side view of the expansion-contraction ladder of the contracted state.
FIG. 2 is a cross-sectional view taken along the line CC in FIG.
FIG. 3 is a sectional view taken along the line DD in FIG.
4 is a cross-sectional view taken along line EE in FIG.
5 is a cross-sectional view taken along line FF in FIG.
6 is a cross-sectional view taken along the line GG in FIG.
FIG. 7 is a partial perspective view of the telescopic ladder.
FIG. 8 is a partial perspective view of the telescopic ladder.
9A and 9B are drawings of a telescopic ladder according to a second embodiment of the present invention, in which FIG. 9A is a side view of the telescopic ladder in an extended state, FIG. 9B is a front view thereof, and FIG. It is a side view of the expansion-contraction ladder of a state.
10 is a cross-sectional view taken along line JJ in FIG.
11 is a cross-sectional view taken along the line KK in FIG. 9;
12A and 12B are drawings of a telescopic ladder according to a conventional example, wherein FIG. 12A is a side view of the telescopic ladder in an extended state, and FIG. 12B is a front view thereof.
13 is a cross-sectional view taken along line AA in FIG.
14 is a cross-sectional view taken along the line BB in FIG.
15A and 15B are drawings of a telescopic ladder according to a conventional example, in which FIG. 15A is a view showing a bent substantially H-shaped column member, and FIG. 15B is a front view of the telescopic ladder.
[Explanation of symbols]
10: telescopic ladder, 11: lower ladder part, 12: middle ladder part, 12a: guide piece, 13: upper ladder part, 14, 15: pillar member, 16: step rail, 16a: handle, 17, 18: leg seat 19, 20: Web, 21-24: Flange, 25: Recess, 26, 27: Inclined surface, 28, 29: Downward guide holder, 30-33: Guide plate piece, 34-37: Inclined surface, 38, 39 : Pillar member, 40: step rail, 41: web, 42, 43: flange, 44: rivet, 45: mounting groove, 46-49: inclined surface, 50: outer flange, 51: protrusion, 52: inclined surface, 53: Overlapping part, 54: Tape, 55, 56: Column member, 57: Foot cross, 58: Web, 59, 60: Flange, 61, 62: Inclined surface, 63: Overlapped part, 64: First pulley, 65: second pulley, 66: rope, 67: clasp, 6 : Stopper, 69: Notch, 70: Third pulley, 71: Fourth pulley, 72: Fifth pulley, 73: Sixth pulley, 74: Seventh pulley, 75: Eight pulley, 76: rope, 77: stopper, 79: telescopic ladder, 80: upward guide holder, 81, 82: guide plate pieces, 83, 84: inclined surface

Claims

In the telescopic ladder having a stopper that can slidably connect the lower ladder part, the middle ladder part, and the upper ladder part, each using a column member made of a groove-shaped member, and fix them in place,
The web length of the pillar member of the middle ladder portion is made larger than the web length of the pillar member of the lower ladder portion and the upper ladder portion, and the section modulus of the middle ladder portion is determined by the lower ladder portion and the upper ladder portion. Larger than the section modulus,
Moreover, each of the sliding parts in said ladder portion and the lower ladder section, and the respective sliding portions of the upper ladder section and the in ladder section, by a slanted sliding surface is symmetrical, the telescopic ladder the oblique sliding mechanism is provided having an inclined surface abutting the case of using up against diagonally, restrains movement transverse to the ladder surface of the member vertical load slides moved relative to the ladder surface And
The pillar member of the upper ladder part is slidably disposed in the pillar member of the middle ladder part, and two downward guide holders are provided with a slight gap at the upper position of the lower ladder part. A telescopic ladder , wherein the pillar member of the middle ladder portion is slidably inserted into two downward guide holders .

2. The telescopic ladder according to claim 1 , wherein first and second pulleys are provided above and below the column member on one side of the middle ladder portion, and are stretched over the first and second pulleys. Both ends of the rope A are fixed to the corresponding pillar members of the upper ladder portion, and the rope A stretched over the first and second pulleys is exposed to the outside of the middle ladder portion. Telescopic ladder characterized by.

2. The telescopic ladder according to claim 1 , wherein the third and fourth pulleys are provided on one column member below the middle ladder portion, and the fifth and sixth pulleys are provided on the other column member below the middle ladder portion. And the seventh and eighth pulleys are provided above and below the other pillar member of the lower ladder portion, and the rope B, one end of which is fixed to the lower portion of the one pillar member of the lower ladder portion, 3 pulleys, 5 pulleys, 8 pulleys, 7 pulleys, 6 pulleys, 4 pulleys, and the other end of the rope B is connected to one pillar member of the lower ladder portion. A telescopic ladder, characterized in that the rope B fixed to the upper part and passing through the seventh and eighth pulleys is exposed to the outside.