JP4064679B2

JP4064679B2 - Chair

Info

Publication number: JP4064679B2
Application number: JP2002028547A
Authority: JP
Inventors: 智一村上; 加代子西村
Original assignee: Kokuyo Co Ltd
Current assignee: Kokuyo Co Ltd
Priority date: 2002-02-05
Filing date: 2002-02-05
Publication date: 2008-03-19
Anticipated expiration: 2022-02-05
Also published as: JP2003225136A; CN1187009C; CN1436501A

Description

【０００１】
【発明の属する技術分野】
本発明は、背凭れを傾動させることができるチルト機構を有した椅子に関する。
【０００２】
【従来の技術】
従来、背座シンクロチルトや背のみのチルトなどを含め種々の背凭れチルト機構を有した椅子が開発されているが、代表的には、脚等を取り付けるベース部材と、このベース部材に基端部を回動可能に支持させた背凭れアームを具備した上で、背座シンクロチルトの場合は、前記ベース部材に前端部をスライドかつ回転可能に支持させ、後端部を背凭れアームの基端部近傍に回転可能に支持させた座と、座の下部に傾動に伴って相対距離の変化する２点間に介在するように接続されたバネを有し、背のみのチルトの場合は、背凭れアームの基端部近傍で座の下部や、背凭れアームの基端部と背凭れの間かつ座の後方下部で、背凭れの傾動に伴って相対距離の変化する２点間に介在するように接続されたバネを有したものが知られている。そしてこれらの椅子は、背凭れアームに固定した背凭れを後傾させた場合にも、バネが背凭れ又は座を起立姿勢に傾動させる傾動力を付与することで常に起立姿勢に戻るように構成されている。
【０００３】
【発明が解決しようとする課題】
ところで、これらチルト機構を有した椅子は、通常、背凭れを後傾させていくに従って、着座者が背凭れにかけなければならない力が直線的に増加し、背凭れを大きく後傾させようと思えば大きな力が必要になる。
【０００４】
背凭れの後傾量が大きくなってくると、着座者はその上半身の体重を背凭れにかけることで背凭れを後傾させていくことになるが、体重をかけるだけでなく筋力を使わないと大きく後傾できなかったり、小柄な人や体重の軽い女性などは満足に後傾姿勢がとれなかったりする。
【０００５】
また小さな力で済むように、背凭れを最大限後傾させた場合でもバネの圧縮量を小さく設定したり、バネ定数の小さなバネを使用したりすると、背凭れが起立姿勢近傍に有るときのバネの初期傾動力も小さくなってしまい、着座者が背凭れに少しもたれただけで、意図しないほど大きく後傾してしまうという問題が有る。
【０００６】
また、通常、バネの傾動力を調整するための機構が有るが、これはバネの初期圧縮量を変えることで傾動させるための初期力を変更し、見かけ上のバネ定数を変化させるもので、背凭れの後傾に従って傾動力が直線的に増加することに変わりはない。
【０００７】
【課題を解決するための手段】
上記の問題点を解決するために、本発明に係る椅子は、脚の上部に取付けられていて上側に座部を有するベース部材に対して相対的に回動可能に配置されており一方のバネ受け部を含む背凭れアームと、一方側がベース部材に連結され背凭れアームをこえた他方側に他方のバネ受け部を有するバネ力伝達部材と、一方のバネ受け部と他方のバネ受け部の間に配置されたコイルスプリングを有し、背凭れアームの後傾時にコイルスプリングを圧縮する構成である椅子であって、背凭れアームが後傾するに従って、背凭れアーム上でバネ力が作用している部分が回動しようとする接線方向に対して相対的に、コイルスプリングを圧縮する方向が徐々に変化していく反力機構を特徴とする。
【０００８】
このようなものであれば、背凭れアームが後傾するに従い、コイルスプリングが圧縮されてコイルスプリングの全反力は大きくなっていくが、同時に背凭れアームが回動しようとする方向に対して、コイルスプリングの全反力の方向が徐々にずれていくため、コイルスプリングが背凭れアームを起立姿勢に戻そうとする反力の有効成分の大きさが増減することになる。背凭れアーム後傾時のコイルスプリングの圧縮の程度と方向のずれ方を設定することで、コイルスプリングが背凭れアームを起立姿勢に戻そうとする反力の変化具合をさまざまに設定でき、ひいては背凭れをチルトさせるための基本的なシステムを変更すること無く、椅子の座り心地の設計の自由度を大きくすることができる。
【０００９】
これは、背凭れの後傾に連動して座がスライドや回転する背座シンクロチルト機構や、座が固定で背凭れのみ後傾する背チルト機構に適用することができる。また、背凭れが起立姿勢近傍に有るときの背凭れ初期反力に対して、背凭れを大きく後傾させていったときの反力の増加程度をあまり大きくしないように設定するには、反力機構が、背凭れアーム上のバネを圧縮する作用点が回動しようとする接線方向とバネが圧縮される方向のなす角度を、背凭れアームが最も起立した姿勢から後傾するに従って大きくなっていくように変化させるものであることが好ましい。こうすることで、背凭れを後傾させていくに従ってコイルスプリングは圧縮されていくが、背凭れアームを起立姿勢に戻そうとする反力の有効成分の大きさとしては、コイルスプリングの圧縮度合いほど大きくならないようにすることができ、背凭れアームの回動接線方向とバネの方向のなす角度の変化のしかたの設定によっては、例えば、背凭れを後傾させる時、起立位置近傍ではほぼ直線的に背凭れ反力を増加させ、ある程度後傾させた位置からさらに後傾させる場合は背凭れ反力の増加程度を緩やかにしていくといったことも可能である。
【００１０】
さらに、より簡単な構造でこれを実現するためには、反力機構を、バネ力伝達部材がベース部材に対して首振り不能に保持されており、背凭れアームが後傾するに従って一方のバネ受け部の水平方向位置がバネ力伝達部材及び他方のバネ受け部に対して相対的に移動していく構成にすればよい。
【００１１】
このようにすれば、背凭れが後傾することで、背凭れアーム側のバネ受け部の水平方向位置が移動していく過程で、バネ力伝達部材上のバネ受け部のベース部材に対する位置は変わらないため、背凭れアームの回動接線方向とバネの方向のなす角度を容易に変化させていくことができる。
【００１２】
そして、背凭れを後傾させる時の、背凭れアーム、コイルスプリングやバネ受け部等、構成部材のスムーズな動作及び無理な力がかからないようにすることでの製品寿命の延長のためには、反力機構を、バネ受け部が背凭れアーム及びバネ力伝達部材に首振り可能に配置された別体の部材であり、背凭れアームの後傾状態にかかわらずコイルスプリングを圧縮する方向に両方のバネ受け部材が互いに向き合っているものにすることが好ましい。
【００１３】
また、よりコンパクトなシステムにするためには、反力機構を、バネ力伝達部材がコイルスプリングの内側を貫通するように配置されている構成にすることが考えられる。こうすることでスペースを有効に活用でき、コンパクトな設計が可能である。さらにこうすることで、背凭れを後傾させていったときに、コイルスプリングの方向が変化できる範囲は、バネ力伝達部材がコイルスプリングの内径に収まる範囲に限定される反面、コイルスプリングに外力など予想外の力が働いた場合にもバネ受けからコイルスプリングが外れるなどのトラブルを防ぐことができる。
【００１４】
さらに、背凭れアームの後傾動作に連動して動かない座部と、ベース部材下方に回転可能に軸止めされた背凭れアームと、背凭れアームの回転軸より後部に前記反力機構を配置することで、椅子全体のシステムを背凭れのみのチルト機構として、シンプルかつ安価でありながら、後傾時の座り心地を大きく向上させることができる。
【００１５】
【発明の実施の形態】
以下、本発明の一実施の形態について図面を参照して説明する。
【００１６】
本実施形態に係る椅子は、図１に側面図、図２に背面図を示すように、キャスタＣを有する脚羽根１１及び脚支柱１２からなる脚１と、この脚１に支持され座２を上部に有する支持体４と、この支持体４の後方から起立する背凭れ３とを具備するもので、背凭れ３を後傾させたときに座２は連動して動かない背のみのチルト機構を有する。
【００１７】
具体的な構造と部品構成について図３、図４を参照して説明する。
【００１８】
すなわち、この椅子は、座２及び背凭れ３全体を昇降させるために前記脚支柱１２の内部に配置されたガススプリングＧＳの上部に、ベース部材２１をその上部に有するガススプリング受け４１を取付け、背凭れアーム３１の前端部近傍を前記ガススプリング受け４１に背凭れアーム回転軸３２をもって回動可能に取り付けている。また、前記背凭れアーム３１は、その前部がベース部材２１の下方に位置するように配置され、座２の後端部より後方で上方に曲がって、その上部で背凭れ３を保持しており、背凭れアーム３１には、ベース部材２１の後端部近傍下方に該当する位置にバネ圧縮作用点３３がくるように、バネ圧縮作用点３３を有するバネ受けブラケット３４を一体に取り付けてある。
【００１９】
前記バネ圧縮作用点３３は、椅子の左右方向の回転軸受を形成しており、ここに上バネ受け部材５１を椅子の前後方向に首振り可能に、バネ受け面が下に向くように取り付けてある。また、前記上バネ受け部材５１の上面部には、バネ力伝達部材５３を貫通しながら前後方向に移動可能なように、前後方向の長穴が設けてある。
【００２０】
次にコイルスプリングＳＰを上バネ受け部材５１のバネ受け面と下バネ受け部材５２のバネ受け面で挟まれるように配置し、ベース部材２１の後端部近傍に、下端部にはネジが形成してあるバネ力伝達部材５３を下向きに、上バネ受け部材５１、コイルスプリングＳＰ、下バネ受け部材５２を貫通するように、またベース部材２１に対して首振り、回転共に不可能なように取付け、バネ力伝達部材５３の下端部に操作部ＳＳをねじ込んで固定する。操作部ＳＳのねじ込み加減によってコイルスプリングＳＰの初期圧縮量を変化させ、背凭れ３の全般的な反力を調整する。ここで下バネ受け部材５２は、バネ力伝達部材５３を貫通させながら、操作部ＳＳに首振り可能なように、底面中心部の窪み部５２２と操作部ＳＳ上に配置した首振り用部材５４の先端Ｒ部５４２が係わるようになっており、その窪みの中央にバネ力伝達部材貫通孔５２１が有る。
【００２１】
図５を参照して本チルト機構の主要部品を詳述すると、脚羽根１１中央部の孔にテーパー嵌合されているガススプリングＧＳの上部に、鋼板の曲げと溶接で作られたガススプリング受け４１がテーパー嵌合されており、ガススプリング受け４１は、その上部に設けた４つの位置決め突起４１２をベース部材２１の４つの位置決め孔２１１に嵌めあわされて、一体になるように溶接してある。
【００２２】
背凭れアーム３１は、略Ｌ型に曲げた丸パイプを２本平行に並べ、上端近傍には背凭れ取付けブラケット３５が２本の丸パイプにまたがるように溶接されており、中間部にはバネ受けブラケット３４が２本の丸パイプにまたがるように溶接されているものであって、その下側先端部近傍に設けた背凭れアーム回転軸取付孔３１１が、ガススプリング受け４１に設けた背凭れアーム回転軸取付孔４１３の位置に隣り合うように、ガススプリング受け４１の左右両外側に配置され、背凭れアーム回転軸３２を２つの部材の取付孔３１１，４１３を貫通するように取付けて、その両端部をＥリングなどで、抜け落ちないように止めている。この構成によって、背凭れアーム３１は背凭れアーム回転軸３２を中心に、ガススプリング受け４１及びベース部材２１に対して回動可能となっており、ガススプリング受け４１の後部に鋼板を上向きに曲げて構成した、後傾ストッパ４１４に当たるまで後傾可能になっている。
【００２３】
バネ受けブラケット３４は、鋼板の４辺を曲げたもので、下向きに曲げた左右辺の略中央部に半円形の切欠きを設け、そこには図示しない樹脂製の軸受け部材がはめ込んである。ここがコイルスプリングＳＰから背凭れアーム３１を起立姿勢に回動させる反力を受ける、バネ圧縮作用点３３である。またバネ受けブラケット３４の中央部には、後述する上バネ受け部材５１との干渉を回避するための円形開口部が設けられている。背凭れアーム３１は前記２本の略Ｌ型丸パイプと背凭れ取付けブラケット３５とバネ受けブラケット３４が一体となることで、背凭れ３を保持するために必要な強度、剛性を確保している。
【００２４】
上バネ受け部材５１は、鋼板を、上面の周囲に下向きの壁面を有する略円形皿形状に絞り加工したもので、この形状によって後述するコイルスプリングＳＰを安定して保持することができる。また、壁面の左右両側に上向き円柱面を有するバネ受け首振り軸５１２を、上バネ受け部材５１の絞り加工時に同時に成形している。上バネ受け部材５１は、その中央部を上下方向に、後述するバネ力伝達部材５３が貫通するため、バネ受け首振り軸５１２を連続した一本の軸とすることができず、その中央部で軸の左右を分断する必要が有るが、コイルスプリングＳＰの反力を受けられる強度が要求されるため、このように一体絞り加工で作成されている。またこの上面には、バネ力伝達部材５３を貫通させるための椅子前後方向に向いたバネ力伝達部材貫通長孔５１１が形成されており、円柱面の下部後方には、メカ部カバー取付孔５１３を有するツバ部が形成されている。
この上バネ受け部材５１は、バネ受け首振り軸５１２を、背凭れアーム３１のバネ圧縮作用点３３に回転可能に配置される。
【００２５】
下バネ受け部材５２は、鋼板を、底面の周囲に上向きの壁面を有する略円形皿形状に絞り加工したもので、この形状によって後述するコイルスプリングＳＰを安定して保持することができる。また、後述する首振り用部材５４を介して、バネ力伝達部材５３に対して首振り回動可能なように、底面が上向きに突出した横向き半円柱形状の窪み部５２２が形成され、その中央部にバネ力伝達部材５３を貫通させるためのバネ力伝達部材貫通孔５２１が形成されている。
コイルスプリングＳＰは、前記上バネ受け部材５１と下バネ受け部材５２に挟まれるように配置される。
【００２６】
メカ部カバーＭＣは、上方に開口し下面を有する略コ字形状で、下面にコイルスプリングＳＰを通すことができる大きさの円形孔を有し、この円形孔外周部から下方に向かって底面を有しない円筒側壁が延びている。また、略コ字形状の下面で前記円形孔の後部に、上バネ受け部材５１のメカ部カバー取付孔５１３に対応する取付孔ＭＣ１が有る。
【００２７】
首振り用部材５４は、下バネ受け部材５２を、後述する操作部ＳＳをねじ込むことでコイルスプリングＳＰを圧縮しながら、バネ力伝達部材５３に対して首振り回動可能に保持するためのもので、上向き鋭角に曲げた鋼板の先端Ｒ部５４２の中央にバネ力伝達部材貫通孔５４１を設け、その下部に肉厚円筒部を有している。首振り用部材５４は、先端Ｒ部５４２が下バネ受け部材５２の窪み部５２２に下面側から接触し、ここに下バネ受け部材５２の仮想的な首振り軸線５５を形成するように配置される。
【００２８】
操作部ＳＳは、外形略円盤形状で中央部の厚み方向に、バネ力伝達部材５３の先端ねじ部５３２にねじ込まれる雌ねじが形成されている。
バネ力伝達部材５３は、半球型上端部の下面に四角柱型の回転止め部５３１を有し、その下面中央部から下向きに円柱型の軸部が伸びており、軸部の下端部近傍には、ねじである先端ねじ部５３２が形成されている。一方、ベース部材２１後端部近傍のバネ力伝達部材取付孔２１２は、四角柱状の凹陥部の底面中央部に円形孔を有することで、バネ力伝達部材５３の回転止め部５３１を嵌合して、後述する操作部ＳＳをねじ込む際に、一体に回転しないように保持できるようになっており、前記円形孔周囲の下面側に下方に伸びる円筒形状を有することで、バネ力伝達部材５３の首振りを防止できるようになっている。
【００２９】
このベース部材２１のバネ力伝達部材取付孔２１２に、上方からバネ力伝達部材５３を貫通させ、回転しないように配置すると同時に、このバネ力伝達部材５３に下方から、上バネ受け部材５１のバネ力伝達部材貫通長孔５１１、コイルスプリングＳＰ、下バネ受け部材５２のバネ力伝達部材貫通孔５２１、首振り用部材５４のバネ力伝達部材貫通孔５４１を貫通させ、先端ねじ部５３２に操作部ＳＳをねじ込むことで、バネ力伝達部材５３が貫通している全ての部材を固定している。また、操作部ＳＳのねじ込み量を加減することで、コイルスプリングＳＰの初期圧縮量を変化させ、背凭れ３の全般的な反力を調整するようになっている。
【００３０】
メカ部カバーＭＣは、上方に開口した略コ字形状部が背凭れア−ム３１の一部をその左右両外側にわたってカバ−し、略コ字形状部の下方に延びる円筒部が上バネ受け部材５１、コイルスプリングＳＰ、下バネ受け部材５２の側面を覆うように下方から配置され、メカ部カバーＭＣの取付孔ＭＣ１を、上バネ受け部材５１のメカ部カバー取付孔５１３に位置をあわせてここでネジ止めされている。ここで、背凭れア−ム３１が最も直立した状態では、操作部ＳＳがメカ部カバーＭＣ下部の円筒部から下方に露出しており、操作可能となっている。
【００３１】
上記の構成による動作について以下に具体的に説明する。
【００３２】
図３は、背凭れ３が最も起立した姿勢を示したものであり、この時バネ圧縮作用点３３は、背凭れアーム回転軸３２に対してほぼ水平後方位置かつ下バネ受け部材５２の首振り軸線５５のほぼ中央真上にある。また、コイルスプリングＳＰは、少なくとも背凭れアーム３１を起立位置に保持できるバネ反力を発生する程度には圧縮された状態であり、この時、バネ力の方向、すなわちコイルスプリングＳＰの中央を通った上下の長さ方向は、バネ圧縮作用点３３がコイルスプリングＳＰの反力によって回動しようとする接線方向、すなわち背凭れアーム回転軸３２の軸心とバネ圧縮作用点３３を結んだ直線に対して、バネ圧縮作用点３３を起点に垂直上向き方向に向いており、この２つの方向はほぼ一致する。
よって、背凭れ直立姿勢近傍では、コイルスプリングＳＰの反力のほぼ全てが背凭れ３を起立姿勢に戻そうとする力になっている。但し、この時のコイルスプリングＳＰの圧縮量は少ないので、反力は小さい。
【００３３】
ここから背凭れアーム３１を後傾させていくと、バネ圧縮作用点３３は背凭れアーム回転軸３２を中心に下前方に向かって回動していくが、下バネ受け部材５２の首振り軸線５５は、前述したように、背凭れの後傾に伴って移動しない構造になっている。またバネ圧縮作用点３３がコイルスプリングＳＰの反力によって回動しようとする接線方向は椅子の後方に向けて傾いていくため、コイルスプリングＳＰの反力の方向に対して前記バネ圧縮作用点３３の回動接線方向はずれていくことになる。
【００３４】
図４は、背凭れ３を大きく後傾させた姿勢を示したものであり、この時バネ圧縮作用点３３は、背凭れアーム回転軸３２に対してほぼ下後方位置かつ下バネ受け部材５２の首振り軸線５５の前上方にある。この時、バネ力の方向、すなわちコイルスプリングＳＰの中央を通った上下の長さ方向は、バネ圧縮作用点３３がコイルスプリングＳＰの反力によって回動しようとする接線方向、すなわち背凭れアーム回転軸３２の軸心とバネ圧縮作用点３３を結んだ直線に対して、バネ圧縮作用点３３を起点に垂直上向き方向に向いており、この２つの方向は大きくずれている。
【００３５】
よって、この時大きく圧縮されたコイルスプリングＳＰの全反力Ｆ１に対して、背凭れアーム３１を起立姿勢に戻す方向に作用する反力成分Ｆyは小さくなる。なお、コイルスプリングＳＰの全反力Ｆ１、バネ圧縮作用点３３に作用する力の成分Ｆx、Ｆyの大きさと方向は、概念的に表わしたものである。
【００３６】
また、起立姿勢から後傾させていくと、反力Ｆyは、その大きさ自体は増加していくが、次第に増加割合は小さくなっていき、増加割合がゼロになる時がくる。ここで反力Ｆyは最大値であり、ここからさらに後傾させていくと、反力Ｆyが今度は減少していく方向に転じ、背凭れアーム回転軸３２、バネ圧縮作用点３３、下バネ受け部材の首振り軸線５５が一直線上に並んだとき反力Ｆyは再度ゼロになる。これよりもさらに後傾させると、背凭れアーム３１は起立姿勢に戻らなくなる。
【００３７】
背凭れアーム３１の後傾は、少なくとも、反力Ｆyが再度ゼロになる以前に停止させる必要がある。実用的には、反力Ｆyが最大値と再度ゼロの間の適切なところで背凭れアーム３１の後傾を停止させることが好ましい。場合によっては、反力Ｆyが最大値になる以前で背凭れアーム３１の後傾を停止させることも好ましい。本実施の形態では、後傾ストッパ４１４を用いて後傾を停止させている。また、背凭れアーム３１の後傾に伴ってコイルスプリングＳＰは椅子の前方に向かって傾いていくが、メカ部カバーＭＣは上バネ受け部材５１に固定されていて、コイルスプリングＳＰと同様に傾いていくため、メカ部カバーＭＣの円筒部は、上バネ受け部材５１、コイルスプリングＳＰ、下バネ受け部材５２の実質的な外形だけをカバーできる大きさで良く、コンパクトな設計にすることができる。ここまでの説明で明らかなように、背凭れアーム回転軸３２、バネ圧縮作用点３３、下バネ受け部材の首振り軸線５５の位置関係の設定を変えれば、背凭れアーム３１が後傾していく過程でコイルスプリングＳＰが背凭れアーム３１を起立姿勢に戻そうとする反力の変化をさまざまに設定することができる。
【００３８】
背凭れが最も起立した姿勢の時、背凭れアーム回転軸３２の軸心位置に対してバネ圧縮作用点３３が椅子の後方側で同高さ以下にあり、バネ圧縮作用点３３の真下に下バネ受け部材５２の首振り軸線５５があれば、背凭れを大きく後傾させていったときの反力の増加程度をあまり大きくしないようにできることは前記説明より明らかであるが、たとえば、バネ圧縮作用点３３の初期位置を、下バネ受け部材５２の首振り軸線５５の真上より後方にすれば、背凭れアーム３１が後傾していく過程で、バネ圧縮作用点３３が下バネ受け部材５２の首振り軸線５５の真上まで回動してくる間は、コイルスプリングＳＰは圧縮されながら方向も背凭れアーム３１を有効に回動させる方向に一致してくるため、背凭れ反力は急激に強くなってくるが、この点を過ぎると背凭れ反力の増加程度は緩やかになってくる。
【００３９】
これらは、下バネ受け部材５２の首振り軸線５５がベース部材２１のバネ力伝達部材取付孔２１２に対して、首振り不能に接続されていることによって、簡単な構造で実現されているが、背凭れ反力の変化程度をより顕著にしたいならば、背凭れアーム３１が後傾していく過程で、下バネ受け部材５２の首振り軸線５５の位置を固定しておくのではなく、積極的に椅子後方に向けて移動させることも考えられる。たとえば、ベース部材２１にバネ力伝達部材５３を、背凭れアーム３１が後傾するに従って、図５において反時計方向に回動するように関連付けて接続すればよい。一例としては、背凭れアーム回転軸３２を背凭れアーム３１と一体となって回転するようにし、背凭れアーム回転軸３２の長さ方向中央部に歯車を一体として回転するように設け、またバネ力伝達部材５３の上端部に椅子の左右方向を回転軸とする歯車を一体に設け、これをベース部材２１の後端部近傍に回転可能に取付け、この２つの歯車間に回転力を伝達できるように、ベース部材２１にいくつかの歯車を配置する。
【００４０】
または、バネ力伝達部材５３の上端よりやや下方をベース部材２１の後端部近傍に椅子の前後方向に回転可能に取付け、背凭れアーム３１が起立位置において、背凭れアーム回転軸３２の長さ方向中央部を下方に偏芯するクランク形状としたうえで背凭れアーム３１と一体となって回転するようにし、バネ力伝達部材５３の上端と背凭れアーム回転軸３２のクランク部を直線状のリンク部材で接続する等して、背凭れアーム３１とバネ力伝達部材５３を連動して回動させることが考えられる。
【００４１】
また、バネ圧縮作用点３３と下バネ受け部材５２の首振り軸線５５を結んだコイルスプリングＳＰの反力の方向と、バネ圧縮作用点３３が背凭れアーム回転軸３２の周りに回動しようとする方向のずれが小さな設計であれば、背凭れアーム３１、バネ力伝達部材５３に一体または固定でもよいが、前記方向のずれを大きくする場合、上・下バネ受け部材５１・５２自体が首を振って、方向の変化するコイルスプリングＳＰに追従する必要がある。こうすることで、コイルスプリングＳＰ自体が曲がったり、上・下バネ受け部材５１・５２に余計な方向の力が加わることが防げるため、スムーズな動作及び製品寿命の延長につながる。
【００４２】
また、バネ力伝達部材５３は、上バネ受け部材５１のバネ力伝達部材貫通長孔５１１、コイルスプリングＳＰ、下バネ受け部材５２のバネ力伝達部材貫通孔５２１、首振り用部材５４のバネ力伝達部材貫通孔５４１、操作部ＳＳを貫通して配置されており、これによって、スペースの有効活用によるコンパクトなシステムとなり、また、予想外の力が働いた場合にも上・下バネ受け部材５１・５２からコイルスプリングＳＰが外れるなどのトラブルを防止できる構造となっている。しかし、背凭れアーム３１を後傾させていったときに、コイルスプリングＳＰの方向が変化できる範囲は、バネ力伝達部材５３がコイルスプリングＳＰの内径に収まる範囲に限定されるため、前記のように、バネ圧縮作用点３３と下バネ受け部材５２の首振り軸線５５を結んだコイルスプリングＳＰの反力の方向と、バネ圧縮作用点３３が背凭れアーム回転軸３２の周りに回動しようとする方向のずれを大きく設計する場合、不利である。
【００４３】
このときは、バネ力伝達部材をコイルスプリングＳＰの左右の外側に配置し、その下端に下バネ受け部材５２を保持する構造にすることが考えられる。こうすることで、背凭れアーム３１を後傾させていったときの、バネ力伝達部材とコイルスプリングＳＰの干渉を防ぐことができ、前記方向のずれを大きく設計することが可能となる。
【００４４】
さらに、ベース部材２１および座２と、背凭れアーム３１の連動機構を設置しない場合、ベース部材２１および座２は、背凭れアーム３１の後傾動作に連動して動かず、また、背凭れアーム回転軸３２より後方に前記反力機構５を配置することで、椅子全体のシステムを背凭れのみのチルト機構として、シンプルかつ安価でありながら、後傾時の座り心地を大きく向上させることができるが、本発明はこれに限らず、背座の動作を連動させた背座シンクロチルト機構に適用させたり、座の前方に前記反力機構５を配置することもできる。
【００４５】
以下、図６を参照して説明する。ここで、図１から図５に対応する部材については、同一の名称、符号を付けている。
【００４６】
背凭れアーム３１は、下方に略９０度曲がった頂点部分を、ベース部材２１の後部上面側に、背凭れアーム回転軸３２によって回動可能に保持されている。背凭れアーム３１は、前方に伸びた先端部近傍が左右に分かれ、その間に上バネ受け部材５１を上バネ受け部材首振り軸５１２で回動可能に保持している。この上にコイルスプリングＳＰが配置され、その上に下バネ受け部材５２が配置されている。
【００４７】
バネ力伝達部材５３は、下バネ受け部材５２、コイルスプリングＳＰ、上バネ受け部材５１、ベース部材２１を貫通し、ベース部材２１に対しては回転及び首振りしないように配置され、上端部近傍で下バネ受け部材５２を下バネ受け部材首振り軸線５５によって首振り可能に保持し、ベース部材２１の下方で操作部ＳＳをねじ込むことによってコイルスプリングＳＰの初期圧縮量を調整できるようにしている。
【００４８】
この構造の場合は、背凭れアーム３１が背凭れアーム回転軸３２を中心に後傾回動すると、背凭れアーム３１の前端部が上バネ受け部材５１を上方に押し上げ、バネ力伝達部材５３の上端部に保持されている下バネ受け部材５２との間でコイルスプリングＳＰを圧縮することになる。
【００４９】
この構造でも、背凭れアーム３１の後傾時に、コイルスプリングＳＰの反力の方向に対してバネ圧縮作用点３３の回動接線方向がずれていき、本発明の所望の効果が得られる。
【００５０】
図７には背座シンクロチルトシステムにこの反力機構を適用した例を作動概念図で示す。
【００５１】
ここに示す反力機構５は、前記図３、図４と基本的に同じであり、バネ力伝達部材５３をコイルスプリングＳＰを貫通させず、その左右両側に配置したものである。こうすれば、背凭れを後傾させていったときに、コイルスプリングの方向が変化できる範囲は、バネ力伝達部材がコイルスプリングの内径に収まる範囲に限定されることがない。
また、背座シンクロ機構は、ベース部材２１の上方に、前部をベース部材２１に対してスライド可能に取付け、背凭れアーム３１前部を背凭れアーム回転軸部分から略直角上方に伸ばした先端部に、ベース部材２１の後部を回動可能に連結して、背凭れアーム３１の後傾と連動するようにしている一般的な構造である。
本発明の反力機構に、座を連動するように連結するだけで実現可能であり、この場合も、本発明の効果が得られることがわかる。
【００５２】
本発明は、以上に示した以外にも、種々変形が可能である。
【００５３】
【発明の効果】
以上に詳述した本発明の椅子は、背凭れアームが後傾し、コイルスプリングが圧縮されるに従い、背凭れアームが回動しようとする方向に対して、コイルスプリングの全反力の方向が徐々にずれていくようにしたので、背凭れをチルトさせるための基本的なシステムを変更すること無く、椅子の座り心地の設計の自由度を大きくすることができる。
【図面の簡単な説明】
【図１】この出願に係る発明である椅子の主要な外観側面を示す図。
【図２】この出願に係る発明である椅子の主要な外観背面を示す図。
【図３】この出願に係る発明である椅子の背凭れが起立姿勢にあるときの主要部品の配置図。
【図４】この出願に係る発明である椅子の背凭れが後傾姿勢にあるときの主要部品の配置図。
【図５】この出願に係る発明である椅子の主要部品の構成図。
【図６】この出願に係る発明である椅子の反力機構が座の前部にある実施形態を示す図。
【図７】この出願に係る発明である椅子の反力機構を背座シンクロチルトシステムに適用した例を示す図。
【符号の説明】
１脚
１１脚羽根
１２脚支柱
Ｃキャスター
ＧＳガススプリング
２座
２１ベース部材
２１１位置決め孔
２１２バネ力伝達部材取付孔
３背凭れ
３１背凭れアーム
３１１背凭れアーム回転軸取付孔
３２背凭れアーム回転軸
３３バネ圧縮作用点
３４バネ受けブラケット
３４１バネ受け干渉防止孔
３５背凭れ取付けブラケット
４支持体
４１ガススプリング受け
４１１ガススプリング嵌合孔
４１２位置決め突起
４１３背凭れアーム回転軸取付孔
４１４後傾ストッパ
５反力機構
５１上バネ受け部材
５１１バネ力伝達部材貫通長孔
５１２バネ受け首振り軸
５２下バネ受け部材
５２１バネ力伝達部材貫通孔
５２２窪み部
５３バネ力伝達部材
５３１回転止め部
５３２先端ねじ部
５４首振り用部材
５４１バネ力伝達部材貫通孔
５４２先端Ｒ部
５５下バネ受け部材の首振り軸線
ＳＰコイルスプリング
ＭＣメカ部カバ−
ＳＳ操作部
ＭＣ１取付孔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chair having a tilt mechanism that can tilt a backrest.
[0002]
[Prior art]
Conventionally, chairs having various backrest tilt mechanisms including back seat sync tilt and back tilt have been developed. Typically, a base member to which a leg or the like is attached and a base end to the base member In the case of back seat synchro tilt, the base member is slidably and rotatably supported at the front end, and the rear end is the base of the backrest arm. In the case of a tilt of the back only, a seat supported rotatably in the vicinity of the end portion and a spring connected so as to be interposed between two points whose relative distance changes with tilting at the lower portion of the seat. Interspersed between two points where the relative distance changes as the backrest tilts between the lower part of the seat near the base end of the backrest arm, between the base end of the backrest arm and the backrest and at the lower back of the seat Those having springs connected in such a manner are known. And these chairs are configured to always return to the standing posture by applying a tilting force to tilt the backrest or the seat to the standing posture even when the backrest fixed to the backrest arm is tilted backward. Has been.
[0003]
[Problems to be solved by the invention]
By the way, a chair having such a tilt mechanism usually seems to increase the force that the seat occupant must apply to the backrest linearly as the backrest is tilted backwards, so that the backrest is greatly tilted backwards. Great power is needed.
[0004]
As the amount of back lean increases, the seated person leans back by applying the weight of the upper body to the back, but does not use weight but also uses muscle strength It is difficult to lean backwards, and small people and women with light weight may not be able to take a backward leaning posture satisfactorily.
[0005]
In addition, even if the backrest is tilted back to the maximum so that a small force is required, if the compression amount of the spring is set to a small value or a spring with a small spring constant is used, the backrest is in the vicinity of the standing posture. The initial tilting force of the spring is also reduced, and there is a problem that the seated person leans back slightly and tilts backwards unintentionally.
[0006]
In addition, there is usually a mechanism for adjusting the tilting power of the spring, but this changes the initial force for tilting by changing the initial compression amount of the spring, and changes the apparent spring constant. The tilting power increases linearly as the backrest tilts backward.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a chair according to the present invention is disposed on an upper part of a leg and is disposed so as to be relatively rotatable with respect to a base member having a seat on the upper side. A backrest arm including a receiving portion, a spring force transmission member having one side connected to the base member and having the other spring receiving portion on the other side over the backrest arm, one spring receiving portion and the other spring receiving portion A chair having a coil spring disposed therebetween and configured to compress the coil spring when the backrest arm is tilted backward, and the spring force acts on the backrest arm as the backrest arm tilts backward. It is characterized by a reaction force mechanism in which the direction in which the coil spring is compressed gradually changes relative to the tangential direction in which the portion being rotated is about to rotate.
[0008]
In such a case, as the backrest arm tilts backward, the coil spring is compressed and the total reaction force of the coil spring increases, but at the same time, the backrest arm tends to rotate. Since the direction of the total reaction force of the coil spring gradually shifts, the magnitude of the effective component of the reaction force that the coil spring tries to return the backrest arm to the standing posture increases or decreases. By setting the degree of compression and direction of the coil spring when the backrest arm is tilted backward, the coil spring can be set in various ways to change the reaction force that tries to return the backrest arm to the standing posture. Without changing the basic system for tilting the backrest, the degree of freedom in designing the seating comfort of the chair can be increased.
[0009]
This can be applied to a back-seat synchro tilt mechanism in which the seat slides and rotates in conjunction with the back tilt of the backrest, or a back tilt mechanism in which the seat is fixed and tilts back only. To set the reaction force so that the degree of increase in the reaction force when the backrest is greatly tilted backward with respect to the initial reaction force when the backrest is in the vicinity of the standing posture is not so large. The force mechanism increases the angle between the tangential direction in which the action point compressing the spring on the backrest arm tries to rotate and the direction in which the spring is compressed as the backrest arm tilts backward from the most upright position. It is preferable that it is changed so as to progress. In this way, the coil spring is compressed as the backrest is tilted backward, but the amount of effective component of the reaction force that attempts to return the backrest arm to the standing posture is the degree of compression of the coil spring. Depending on the setting of how the angle between the rotation tangent direction of the backrest arm and the direction of the spring changes, for example, when the backrest is tilted backward, it is almost straight in the vicinity of the standing position. For example, when the back reaction force is increased and the vehicle is further tilted backward from a position where the back reaction force is tilted to some extent, the increase in the back reaction force can be moderated.
[0010]
Furthermore, in order to achieve this with a simpler structure, the reaction force mechanism is configured such that the spring force transmission member is held so as not to swing with respect to the base member, and one spring moves as the backrest arm tilts backward. What is necessary is just to make it the structure which the horizontal direction position of a receiving part moves relatively with respect to a spring force transmission member and the other spring receiving part.
[0011]
In this way, the position of the spring receiving portion on the spring force transmitting member relative to the base member is changed in the process of moving the horizontal position of the spring receiving portion on the backrest arm side as the backrest tilts backward. Since it does not change, the angle formed by the rotational tangent direction of the backrest arm and the direction of the spring can be easily changed.
[0012]
And, in order to extend the product life by preventing the backrest arm, coil spring, spring receiving part, etc. from smoothly acting and excessive force when tilting the backrest backward, The reaction force mechanism is a separate member in which the spring receiving part is swingably disposed on the backrest arm and the spring force transmission member, both in the direction of compressing the coil spring regardless of the back tilt state of the backrest arm. It is preferable that the spring receiving members are opposed to each other.
[0013]
In order to make the system more compact, it is conceivable that the reaction force mechanism is configured such that the spring force transmission member is disposed so as to penetrate the inside of the coil spring. In this way, the space can be used effectively and a compact design is possible. Furthermore, when the backrest is tilted backward, the range in which the direction of the coil spring can be changed is limited to the range in which the spring force transmission member can be accommodated within the inner diameter of the coil spring. Even when an unexpected force is applied, troubles such as the coil spring coming off from the spring receiver can be prevented.
[0014]
In addition, the seat that does not move in conjunction with the backward tilting motion of the backrest arm, the backrest arm that is pivotally fixed to the bottom of the base member, and the reaction force mechanism that is located behind the rotation axis of the backrest arm By doing so, the system of the entire chair can be used as a tilt mechanism with only a backrest, and the sitting comfort when tilting backward can be greatly improved while being simple and inexpensive.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0016]
As shown in a side view in FIG. 1 and a rear view in FIG. 2, the chair according to the present embodiment includes a leg 1 including a leg blade 11 having a caster C and a leg column 12, and a seat 2 supported by the leg 1. A support 4 having an upper portion and a backrest 3 standing up from the rear of the support 4, and when the backrest 3 is tilted backward, the seat 2 does not move in conjunction with the back-only tilt mechanism. Have
[0017]
A specific structure and component configuration will be described with reference to FIGS.
[0018]
That is, in this chair, a gas spring receiver 41 having a base member 21 at the upper part is attached to the upper part of the gas spring GS arranged inside the leg column 12 in order to raise and lower the seat 2 and the backrest 3 as a whole. The vicinity of the front end portion of the backrest arm 31 is rotatably attached to the gas spring receiver 41 with a backrest arm rotating shaft 32. The backrest arm 31 is disposed so that the front portion thereof is positioned below the base member 21, bends upward from the rear end portion of the seat 2, and holds the backrest 3 at the upper portion thereof. A spring receiving bracket 34 having a spring compression action point 33 is integrally attached to the backrest arm 31 so that the spring compression action point 33 comes to a position corresponding to the lower part near the rear end of the base member 21. .
[0019]
The spring compression action point 33 forms a left and right rotating bearing of the chair, and the upper spring receiving member 51 is attached to the chair so that the spring receiving surface can be swung down in the front-rear direction of the chair. is there. The upper spring receiving member 51 has an elongated hole in the front-rear direction so as to be movable in the front-rear direction while penetrating the spring force transmission member 53.
[0020]
Next, the coil spring SP is disposed so as to be sandwiched between the spring receiving surface of the upper spring receiving member 51 and the spring receiving surface of the lower spring receiving member 52, and a screw is formed in the lower end portion near the rear end portion of the base member 21. The spring force transmitting member 53 is directed downward so as to penetrate the upper spring receiving member 51, the coil spring SP, and the lower spring receiving member 52, and the base member 21 can be swung and cannot be rotated. The operation portion SS is screwed and fixed to the lower end portion of the attachment and spring force transmission member 53. The initial reaction amount of the coil spring SP is changed by adjusting the screwing of the operation portion SS, and the general reaction force of the backrest 3 is adjusted. Here, the lower spring receiving member 52 oscillates through the spring force transmitting member 53, and the swinging member 54 disposed on the depression 522 at the center of the bottom surface and the operation portion SS so as to be able to swing to the operation portion SS. The tip end R portion 542 is involved, and a spring force transmission member through hole 521 is provided at the center of the recess.
[0021]
Referring to FIG. 5, the main components of the tilt mechanism will be described in detail. A gas spring receiver made by bending and welding a steel plate is formed on the upper part of the gas spring GS that is taper-fitted into the hole at the center of the leg blade 11. 41 is taper-fitted, and the gas spring receiver 41 is welded so that the four positioning protrusions 412 provided on the gas spring receiver 41 are fitted into the four positioning holes 211 of the base member 21 and integrated. .
[0022]
The backrest arm 31 has two round pipes bent in a substantially L shape arranged in parallel, and a backrest mounting bracket 35 is welded so as to straddle the two round pipes in the vicinity of the upper end. The receiving bracket 34 is welded so as to straddle two round pipes, and a backrest arm rotating shaft mounting hole 311 provided in the vicinity of the lower end portion of the receiving bracket 34 is provided on the gas spring receiver 41. Arranged on the left and right outer sides of the gas spring receiver 41 so as to be adjacent to the position of the arm rotating shaft mounting hole 413, the backrest arm rotating shaft 32 is mounted so as to pass through the mounting holes 311 and 413 of the two members, Both ends are stopped with an E-ring to prevent it from falling off. With this configuration, the backrest arm 31 can rotate with respect to the gas spring receiver 41 and the base member 21 around the backarm rotation shaft 32, and the steel plate is bent upward at the rear of the gas spring receiver 41. It is possible to tilt backward until it hits the backward tilt stopper 414 configured as described above.
[0023]
The spring receiving bracket 34 is formed by bending four sides of a steel plate, and a semicircular cutout is provided in a substantially central portion of the left and right sides bent downward, and a resin bearing member (not shown) is fitted therein. This is a spring compression action point 33 that receives a reaction force that causes the backrest arm 31 to rotate to a standing posture from the coil spring SP. A circular opening for avoiding interference with an upper spring receiving member 51 described later is provided at the center of the spring receiving bracket 34. The backrest arm 31 secures strength and rigidity necessary for holding the backrest 3 by integrating the two substantially L-shaped round pipes, the backrest mounting bracket 35 and the spring receiving bracket 34. .
[0024]
The upper spring receiving member 51 is obtained by drawing a steel plate into a substantially circular dish shape having a downward wall surface around the upper surface, and this shape can stably hold a coil spring SP described later. In addition, the spring bearing swinging shaft 512 having upward cylindrical surfaces on both the left and right sides of the wall surface is simultaneously formed when the upper spring receiving member 51 is drawn. Since the spring force transmitting member 53 (described later) penetrates the center portion of the upper spring receiving member 51 in the vertical direction, the spring receiving swinging shaft 512 cannot be formed as a single continuous shaft. However, it is necessary to divide the left and right sides of the shaft, but the strength required to receive the reaction force of the coil spring SP is required. In addition, a spring force transmission member through long hole 511 oriented in the front-rear direction of the chair for penetrating the spring force transmission member 53 is formed on the upper surface, and a mechanical part cover mounting hole 513 is formed at the lower rear of the cylindrical surface. A brim part having the shape is formed.
The upper spring receiving member 51 is disposed so that the spring receiving swinging shaft 512 can rotate at the spring compression action point 33 of the backrest arm 31.
[0025]
The lower spring receiving member 52 is obtained by drawing a steel plate into a substantially circular dish shape having an upward wall surface around the bottom surface, and this shape can stably hold a coil spring SP described later. In addition, a laterally semi-cylindrical recess 522 having a bottom surface protruding upward is formed so as to be able to swing and rotate with respect to the spring force transmission member 53 via a swinging member 54 described later. A spring force transmission member through-hole 521 for allowing the spring force transmission member 53 to pass therethrough is formed.
The coil spring SP is disposed so as to be sandwiched between the upper spring receiving member 51 and the lower spring receiving member 52.
[0026]
The mechanical cover MC has a substantially U-shape that opens upward and has a lower surface. The mechanical cover MC has a circular hole with a size that allows the coil spring SP to pass through the lower surface. The cylindrical side wall which does not have is extended. In addition, a mounting hole MC1 corresponding to the mechanical part cover mounting hole 513 of the upper spring receiving member 51 is provided at the rear of the circular hole on the substantially U-shaped lower surface.
[0027]
The swinging member 54 holds the lower spring receiving member 52 so as to be swingable with respect to the spring force transmission member 53 while compressing the coil spring SP by screwing an operation portion SS described later. Thus, a spring force transmission member through hole 541 is provided at the center of the tip R portion 542 of the steel plate bent at an acute angle upward, and a thick cylindrical portion is provided at the lower portion thereof. The swinging member 54 is arranged such that the tip R portion 542 contacts the recess 522 of the lower spring receiving member 52 from the lower surface side, and forms a virtual swinging axis 55 of the lower spring receiving member 52 here. The
[0028]
The operation portion SS has a substantially outer disk shape and is formed with a female screw to be screwed into the tip screw portion 532 of the spring force transmission member 53 in the thickness direction of the central portion.
The spring force transmission member 53 has a quadrangular columnar rotation stop portion 531 on the lower surface of the hemispherical upper end portion, and a cylindrical shaft portion extends downward from the center portion of the lower surface, near the lower end portion of the shaft portion. Is formed with a tip screw portion 532 which is a screw. On the other hand, the spring force transmission member mounting hole 212 in the vicinity of the rear end portion of the base member 21 has a circular hole at the center of the bottom surface of the square columnar recess, and thus the rotation stop portion 531 of the spring force transmission member 53 is fitted. Thus, when screwing in the operation portion SS described later, it can be held so as not to rotate integrally, and has a cylindrical shape extending downward on the lower surface side around the circular hole, so that the spring force transmission member 53 You can prevent swinging.
[0029]
The spring force transmission member 53 is penetrated from above into the spring force transmission member mounting hole 212 of the base member 21 so as not to rotate, and at the same time, the spring of the upper spring receiving member 51 from below the spring force transmission member 53. The force transmission member through long hole 511, the coil spring SP, the spring force transmission member through hole 521 of the lower spring receiving member 52, and the spring force transmission member through hole 541 of the swinging member 54 are penetrated, and the distal end screw portion 532 has an operation portion. By screwing SS, all members through which the spring force transmission member 53 passes are fixed. Further, by adjusting the screwing amount of the operation portion SS, the initial compression amount of the coil spring SP is changed, and the general reaction force of the backrest 3 is adjusted.
[0030]
The mechanical part cover MC has a substantially U-shaped part opened upward to cover a part of the back arm 31 over both the left and right outer sides, and a cylindrical part extending below the substantially U-shaped part is an upper spring support. The member 51, the coil spring SP, and the lower spring receiving member 52 are arranged from below so as to cover the side surfaces, and the mounting hole MC1 of the mechanical unit cover MC is aligned with the mechanical unit cover mounting hole 513 of the upper spring receiving member 51. It is screwed here. Here, when the backrest arm 31 is in the most upright state, the operation portion SS is exposed downward from the cylindrical portion below the mechanical portion cover MC and can be operated.
[0031]
The operation according to the above configuration will be specifically described below.
[0032]
FIG. 3 shows a posture in which the backrest 3 stands up most. At this time, the spring compression action point 33 is located at a position substantially horizontally rearward with respect to the backrest arm rotating shaft 32 and the lower spring receiving member 52 swings. Near the center of the axis 55. Further, the coil spring SP is in a compressed state to generate a spring reaction force that can hold at least the backrest arm 31 in the upright position. At this time, the coil spring SP passes through the direction of the spring force, that is, through the center of the coil spring SP. The vertical length direction is a tangential direction in which the spring compression action point 33 tries to rotate by the reaction force of the coil spring SP, that is, a straight line connecting the axis of the backrest arm rotation shaft 32 and the spring compression action point 33. On the other hand, the direction of the spring compression acting point 33 is the vertical upward direction starting from the starting point, and these two directions substantially coincide.
Therefore, in the vicinity of the backrest upright posture, almost all of the reaction force of the coil spring SP is a force for returning the backrest 3 to the upright posture. However, since the compression amount of the coil spring SP at this time is small, the reaction force is small.
[0033]
When the backrest arm 31 is tilted backward from here, the spring compression action point 33 rotates downward and forward about the backrest arm rotation shaft 32, but the swing axis of the lower spring receiving member 52 As described above, 55 has a structure that does not move as the back leans backward. Further, since the tangential direction in which the spring compression action point 33 tries to rotate by the reaction force of the coil spring SP is inclined toward the rear of the chair, the spring compression action point 33 with respect to the direction of the reaction force of the coil spring SP. The rotational tangent direction of will deviate.
[0034]
FIG. 4 shows a posture in which the backrest 3 is greatly tilted rearward. At this time, the spring compression action point 33 is substantially at the lower rear position with respect to the backrest arm rotating shaft 32 and the lower spring receiving member 52 is moved. It is in front upper direction of the swing axis 55. At this time, the direction of the spring force, that is, the vertical direction passing through the center of the coil spring SP, is the tangential direction in which the spring compression action point 33 tries to rotate by the reaction force of the coil spring SP, that is, the back arm rotation. With respect to the straight line connecting the axis of the shaft 32 and the spring compression action point 33, the spring compression action point 33 is directed in the vertical upward direction, and the two directions are greatly deviated.
[0035]
Therefore, the reaction force component Fy acting in the direction in which the backrest arm 31 is returned to the standing posture is reduced with respect to the total reaction force F1 of the coil spring SP that is greatly compressed at this time. The magnitude and direction of the total reaction force F1 of the coil spring SP and the force components Fx and Fy acting on the spring compression action point 33 are conceptually represented.
[0036]
Further, when the vehicle is tilted backward from the standing posture, the magnitude of the reaction force Fy itself increases, but the rate of increase gradually decreases, and the time when the rate of increase becomes zero comes. Here, the reaction force Fy is the maximum value. If the reaction force Fy is further tilted backward from here, the reaction force Fy turns in the direction of decreasing this time, and the backrest arm rotating shaft 32, the spring compression action point 33, the lower spring When the swing axis 55 of the receiving member is aligned on a straight line, the reaction force Fy becomes zero again. When tilted further backward than this, the backrest arm 31 cannot return to the standing posture.
[0037]
The backward tilt of the backrest arm 31 needs to be stopped at least before the reaction force Fy becomes zero again. Practically, it is preferable to stop the backward tilting of the backrest arm 31 at an appropriate position between the maximum value of the reaction force Fy and zero again. In some cases, it is also preferable to stop the backward tilting of the backrest arm 31 before the reaction force Fy reaches the maximum value. In this embodiment, the backward tilt is stopped using the backward tilt stopper 414. As the backrest arm 31 tilts backward, the coil spring SP tilts toward the front of the chair, but the mechanical cover MC is fixed to the upper spring receiving member 51 and tilts in the same manner as the coil spring SP. Therefore, the cylindrical portion of the mechanical portion cover MC may have a size that can cover only the substantial outer shape of the upper spring receiving member 51, the coil spring SP, and the lower spring receiving member 52, and can be made compact. . As apparent from the above description, if the setting of the positional relationship of the backrest arm rotation shaft 32, the spring compression action point 33, and the swing axis 55 of the lower spring receiving member is changed, the backrest arm 31 tilts backward. In the course of going, it is possible to set various changes in reaction force that the coil spring SP tries to return the backrest arm 31 to the standing posture.
[0038]
When the backrest is in the most upright posture, the spring compression action point 33 is below the same height on the rear side of the chair with respect to the axial center position of the backrest arm rotation shaft 32, and is below the spring compression action point 33. It is clear from the above description that if the swinging axis 55 of the spring receiving member 52 is present, the degree of increase in the reaction force when the backrest is greatly tilted backward can be prevented from becoming too large. If the initial position of the action point 33 is set to the rear from directly above the swing axis 55 of the lower spring receiving member 52, the spring compression action point 33 becomes lower spring receiving member in the process in which the backrest arm 31 tilts backward. While the coil spring SP is being rotated to a position just above the swing axis 55 of 52, the direction of the coil spring SP coincides with the direction in which the backrest arm 31 is effectively rotated. It suddenly gets stronger, but this Past the point about the increase of the backrest reaction force becomes moderate.
[0039]
These are realized with a simple structure by connecting the swing axis 55 of the lower spring receiving member 52 to the spring force transmission member mounting hole 212 of the base member 21 so as not to swing. If it is desired to make the degree of change in the backrest reaction force more prominent, the position of the swing axis 55 of the lower spring receiving member 52 is not fixed in the process in which the backrest arm 31 is tilted backward. It is also possible to move it toward the back of the chair. For example, the spring force transmission member 53 may be connected to the base member 21 so as to rotate counterclockwise in FIG. 5 as the backrest arm 31 tilts backward. As an example, the backrest arm rotation shaft 32 is rotated integrally with the backrest arm 31, and a gear is provided to rotate integrally with the backrest arm rotation shaft 32 in the longitudinal direction. A gear having a rotation axis in the left-right direction of the chair is integrally provided at the upper end of the force transmission member 53, and this is rotatably mounted in the vicinity of the rear end of the base member 21, so that the rotational force can be transmitted between the two gears. Thus, several gears are arranged on the base member 21.
[0040]
Alternatively, a length slightly lower than the upper end of the spring force transmission member 53 is attached to the vicinity of the rear end of the base member 21 so as to be rotatable in the front-rear direction of the chair, and the length of the backrest arm rotating shaft 32 when the backrest arm 31 is in the standing position. The center of the direction is made to be a crank shape that is eccentric downward, and is rotated integrally with the backrest arm 31, and the upper end of the spring force transmission member 53 and the crank portion of the backrest arm rotating shaft 32 are linear. It is conceivable to rotate the backrest arm 31 and the spring force transmission member 53 in conjunction with each other by connecting with a link member.
[0041]
Further, the direction of the reaction force of the coil spring SP connecting the spring compression action point 33 and the swing axis 55 of the lower spring receiving member 52 and the spring compression action point 33 tries to rotate around the backrest arm rotation shaft 32. If the displacement in the direction is small, the backrest arm 31 and the spring force transmission member 53 may be integrated or fixed. However, when the displacement in the direction is increased, the upper and lower spring receiving members 51 and 52 themselves are connected to the neck. It is necessary to follow the coil spring SP whose direction changes. By doing so, it is possible to prevent the coil spring SP itself from being bent or to apply an extra force to the upper and lower spring receiving members 51 and 52, leading to a smooth operation and an extended product life.
[0042]
The spring force transmission member 53 includes a spring force transmission member through long hole 511 of the upper spring receiving member 51, a coil spring SP, a spring force transmission member through hole 521 of the lower spring receiving member 52, and a spring force of the swinging member 54. The transmission member through-hole 541 and the operation portion SS are disposed so as to form a compact system by effectively using the space, and the upper and lower spring receiving members 51 even when an unexpected force is applied. -It has a structure that can prevent troubles such as the coil spring SP coming off from 52. However, since the range in which the direction of the coil spring SP can be changed when the backrest arm 31 is tilted backward is limited to the range in which the spring force transmission member 53 fits within the inner diameter of the coil spring SP, as described above. Further, the direction of the reaction force of the coil spring SP connecting the spring compression action point 33 and the swing axis 55 of the lower spring receiving member 52 and the spring compression action point 33 tries to rotate around the backrest arm rotation shaft 32. This is disadvantageous when designing a large deviation in the direction to be performed.
[0043]
At this time, it can be considered that the spring force transmission member is disposed on the left and right outer sides of the coil spring SP and the lower spring receiving member 52 is held at the lower end thereof. By doing so, it is possible to prevent interference between the spring force transmission member and the coil spring SP when the backrest arm 31 is tilted backward, and it is possible to design a large deviation in the direction.
[0044]
Further, when the interlocking mechanism between the base member 21 and the seat 2 and the backrest arm 31 is not installed, the base member 21 and the seat 2 do not move in conjunction with the backward tilting operation of the backrest arm 31, and the backrest arm By disposing the reaction force mechanism 5 behind the rotating shaft 32, it is possible to greatly improve the sitting comfort when tilting backward while using the entire chair system as a tilt mechanism with only a backrest while being simple and inexpensive. However, the present invention is not limited to this, and can be applied to a back seat synchro tilt mechanism in which the motion of the back seat is linked, or the reaction force mechanism 5 can be arranged in front of the seat.
[0045]
Hereinafter, a description will be given with reference to FIG. Here, members corresponding to those in FIGS. 1 to 5 have the same names and symbols.
[0046]
The backrest arm 31 is pivotally held by a backrest arm rotating shaft 32 at the apex portion bent downward by approximately 90 degrees on the upper surface side of the rear portion of the base member 21. In the backrest arm 31, the vicinity of the front end portion extending forward is divided into right and left, and the upper spring receiving member 51 is rotatably held by the upper spring receiving member swinging shaft 512 therebetween. A coil spring SP is disposed thereon, and a lower spring receiving member 52 is disposed thereon.
[0047]
The spring force transmitting member 53 passes through the lower spring receiving member 52, the coil spring SP, the upper spring receiving member 51, and the base member 21, and is disposed so as not to rotate and swing with respect to the base member 21, and near the upper end portion. Thus, the lower spring receiving member 52 is swingably held by the lower spring receiving member swinging axis 55, and the operation portion SS is screwed under the base member 21 so that the initial compression amount of the coil spring SP can be adjusted. .
[0048]
In the case of this structure, when the backrest arm 31 tilts and rotates backward about the backarm rotation shaft 32, the front end of the backrest arm 31 pushes the upper spring receiving member 51 upward, and the spring force transmission member 53 The coil spring SP is compressed between the lower spring receiving member 52 held at the upper end portion.
[0049]
Even in this structure, when the backrest arm 31 is tilted backward, the rotational tangent direction of the spring compression acting point 33 is shifted from the direction of the reaction force of the coil spring SP, and the desired effect of the present invention can be obtained.
[0050]
FIG. 7 is an operation conceptual diagram showing an example in which this reaction force mechanism is applied to a back seat synchro tilt system.
[0051]
The reaction force mechanism 5 shown here is basically the same as that shown in FIGS. 3 and 4, and the spring force transmission member 53 is disposed on both the left and right sides of the coil spring SP without penetrating the coil spring SP. In this way, the range in which the direction of the coil spring can be changed when the backrest is tilted backward is not limited to the range in which the spring force transmission member fits within the inner diameter of the coil spring.
The back seat synchronization mechanism has a front end that is slidably attached to the base member 21 above the base member 21 and a front end of the backrest arm 31 that extends substantially perpendicularly upward from the backarm rotation shaft portion. This is a general structure in which the rear part of the base member 21 is connected to the part so as to be rotatable, and interlocked with the rearward inclination of the backrest arm 31.
It can be realized simply by connecting the seat to the reaction force mechanism of the present invention in an interlocking manner, and it can be seen that the effects of the present invention can also be obtained in this case.
[0052]
The present invention can be variously modified in addition to the above.
[0053]
【The invention's effect】
In the chair of the present invention described in detail above, as the backrest arm tilts backward and the coil spring is compressed, the direction of the total reaction force of the coil spring is relative to the direction in which the backrest arm tries to rotate. Since it is shifted gradually, the degree of freedom in designing the sitting comfort of the chair can be increased without changing the basic system for tilting the backrest.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing a main external appearance side surface of a chair according to the present invention.
FIG. 2 is a view showing a main appearance rear surface of the chair according to the invention of this application.
FIG. 3 is a layout diagram of main components when the backrest of the chair according to the present invention is in a standing posture.
FIG. 4 is a layout view of main parts when the backrest of the chair according to the present invention is in a backward tilted posture.
FIG. 5 is a configuration diagram of main components of a chair according to the invention according to this application.
FIG. 6 is a view showing an embodiment in which the reaction force mechanism of the chair according to the present invention is in the front part of the seat.
FIG. 7 is a view showing an example in which a chair reaction force mechanism according to the present invention is applied to a back seat synchro tilt system;
[Explanation of symbols]
1 leg
11 leg feathers
12 leg support
C caster
GS gas spring
2 seats
21 Base member
211 Positioning hole
212 Spring force transmission member mounting hole
3 Backrest
31 Backrest arm
311 Back arm rotation shaft mounting hole
32 Backrest arm rotation axis
33 Spring compression point
34 Spring support bracket
341 Spring receiving interference prevention hole
35 Backrest mounting bracket
4 Support
41 Gas spring receiver
411 Gas spring fitting hole
412 Positioning protrusion
413 Back arm rotation shaft mounting hole
414 Back tilt stopper
5 Reaction force mechanism
51 Upper spring receiving member
511 Spring force transmission member through long hole
512 Spring bearing swinging shaft
52 Lower spring bearing member
521 Spring force transmission member through hole
522 depression
53 Spring force transmission member
531 Anti-rotation part
532 Tip thread
54 Swing members
541 Spring force transmission member through hole
542 Tip R
55 Swing axis of lower spring bearing member
SP coil spring
MC Mechanical cover
SS operation section
MC1 mounting hole

Claims

A base member attached to the upper part of the leg and having a seat on the upper side;
A backrest arm that is arranged to be rotatable relative to the base member and includes one spring receiving portion;
A spring force transmission member having one spring receiving portion on the other end side of which the one end side is connected to the base member and exceeds the backrest arm;
A coil spring disposed between one spring receiving portion and the other spring receiving portion;
A chair that is configured to compress a coil spring when the backrest arm is tilted backward,
As the backrest arm tilts backward, the direction in which the coil spring is compressed gradually changes relative to the tangential direction in which the portion on which the spring force is applied rotates. chair have a reaction force mechanism, to be characterized by one of the spring receiving portion of the reaction force mechanism is a member of swivelably arranged separate backrest arm.

A base member attached to the upper part of the leg and having a seat on the upper side;
A backrest arm that is arranged to be rotatable relative to the base member and includes one spring receiving portion;
A spring force transmission member having one spring receiving portion on the other end side of which the one end side is connected to the base member and exceeds the backrest arm;
A coil spring disposed between one spring receiving portion and the other spring receiving portion;
A chair that is configured to compress a coil spring when the backrest arm is tilted backward,
As the backrest arm tilts backward, the direction in which the coil spring is compressed gradually changes relative to the tangential direction in which the portion on which the spring force is applied rotates. have a reaction force mechanism, a chair, wherein the other of the spring receiving portion of the reaction force mechanism is a member of swivelably arranged separate the spring force transmission member.

A base member attached to the upper part of the leg and having a seat on the upper side;
A backrest arm that is arranged to be rotatable relative to the base member and includes one spring receiving portion;
A spring force transmission member having one spring receiving portion on the other end side of which the one end side is connected to the base member and exceeds the backrest arm;
A coil spring disposed between one spring receiving portion and the other spring receiving portion;
A chair that is configured to compress a coil spring when the backrest arm is tilted backward,
As the backrest arm tilts backward, the direction in which the coil spring is compressed gradually changes relative to the tangential direction in which the portion on which the spring force is applied rotates. It has a reaction force mechanism, the spring force transmission member of the reaction force mechanism is held so as not to swing with respect to the base member, and as the backrest arm tilts backward, the horizontal position of one spring receiving part is the spring force. A chair that moves relative to the transmission member and the other spring receiving portion.

A base member attached to the upper part of the leg and having a seat on the upper side;
A backrest arm that is arranged to be rotatable relative to the base member and includes one spring receiving portion;
A spring force transmission member having one spring receiving portion on the other end side of which the one end side is connected to the base member and exceeds the backrest arm;
A coil spring disposed between one spring receiving portion and the other spring receiving portion;
A chair that is configured to compress a coil spring when the backrest arm is tilted backward,
As the backrest arm tilts backward, the direction in which the coil spring is compressed gradually changes relative to the tangential direction in which the portion on which the spring force is applied rotates. It has a reaction force mechanism, and the spring receiving part of the reaction force mechanism is a separate member that is swingably disposed on the backrest arm and the spring force transmission member, and the coil spring regardless of the back tilt state of the backrest arm A chair characterized in that both spring receiving members face each other in the direction of compressing.

On the backrest arm of the reaction force mechanism, the angle between the tangential direction in which the point of compression of the spring rotates and the direction in which the spring is compressed increases as the backrest arm tilts backward from the most upright position. The chair according to claim 1, 2, 3, or 4 , wherein the chair changes.

The chair according to claim 1, 2, 3, 4 or 5 , wherein the spring force transmission member of the reaction force mechanism is disposed so as to penetrate the inside of the coil spring.

The seat that does not move in conjunction with the backward tilting motion of the backrest arm, the backrest arm that is pivotally fixed to the bottom of the base member, and the reaction force mechanism disposed behind the rotation axis of the backrest arm The chair according to claim 1, 2, 3, 4, 5 or 6 .