JP4133427B2

JP4133427B2 - Chair

Info

Publication number: JP4133427B2
Application number: JP2003044655A
Authority: JP
Inventors: 智一村上
Original assignee: Kokuyo Co Ltd
Current assignee: Kokuyo Co Ltd
Priority date: 2003-02-21
Filing date: 2003-02-21
Publication date: 2008-08-13
Anticipated expiration: 2023-02-21
Also published as: JP2004248980A

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、特許文献１に示されるように、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】
【特許文献１】
特開平７−２５５５６２号公報
【０００４】
【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。
【０００５】
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。
【０００６】
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。
【０００７】
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。
【０００８】
【課題を解決するための手段】
上記の問題点を簡易に解決するために、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と、このベース部材に対して相対的に回動可能に配置された背凭れアームと、背凭れアームに反力を付与する反力機構とを具備してなり、前記反力機構が、背凭れアーム側に備えられた一方のバネ受け部と、一端側がベース部材に連結され背凭れアームをこえた他端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とを有し、背凭れアームの後傾時にコイルスプリングを圧縮可能にするとともに、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ように構成されているものである。そして、前記反力機構のバネ力伝達部材をベース部材に対し首振り不能に保持し、背凭れアームの後傾状態にかかわらず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相対的にほぼ変わらないようにして、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のみがベース部材に対して変化し、コイルスプリングを圧縮する方向がベース部材に対してほぼ変わらないように構成したものであって、反力機構の一方のバネ受け部がバネ力伝達部材にほぼ首振り不能に配置された別体の部材であり、当該一方のバネ受け部と背凭れアームとの間に、背凭れアームの後傾動作に伴い背凭れアーム上でバネ力が作用する部分をスライド移動させつつ一方のバネ受け部が受けるバネ力を当該背凭れアームに受圧させるスライド受圧機構を設けていることを特徴とする。
【０００９】
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。しかも、一方のバネ受け部の水平方向位置をバネ力伝達部材や他方のバネ受け部に対して相対的にほぼ変わらないようにして、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のみが変化し、コイルスプリングを圧縮する方向がほぼ一定方向を向いているようにしたので、例えば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、これに伴ってコイルスプリングを圧縮する方向が変化する構成のものに比べて、背凭れの傾動角度と反力の増減の程度とを好適に比例させて反力を一定に保つような設計等が比較的容易になる上に、反力機構の各部の構成部材にスムーズな動作を付与することができ、またバネ受け部等に無理な力がかかることを有効に回避可能となるし、反力機構を被覆するカバーもコイルスプリングの動作に連動する可動のものにする必要がないため定位置に確実に取り付けておくことができるようになる。
【００１０】
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。
【００１１】
さらに、本発明に係る椅子では、反力機構の一方のバネ受け部がバネ力伝達部材にほぼ首振り不能に配置された別体の部材であり、当該一方のバネ受け部と背凭れアームとの間に、背凭れアームの後傾動作に伴い背凭れアーム上でバネ力が作用する部分をスライド移動させつつ一方のバネ受け部が受けるバネ力を当該背凭れアームに受圧させるスライド受圧機構を設けている。背凭れアームが後傾すると、背凭れアーム上のバネ力が作用する部分が当該背凭れアーム上を次第に回転中心から遠い部位に移動することになるが、かかるスライド受圧機構を設けているので、このような部材同士が係り合った状態での相対動作を円滑に安定して行わせることができる。
【００１２】
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。
【００１３】
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となる。
【００１４】
好ましいスライド受圧機構としては、背凭れアーム側に設けた下向き凸状の受圧面と、一方のバネ受け部側に設けた上向き凹状の与圧面とから構成されるものが挙げられる。すなわち、背凭れアームが後傾すると、一方のバネ受け部のベース部材に対する角度がほぼ変わらないのに対して、背凭れアームのなす角度が漸次増大することになるが、上記のように構成しておけば、両部材の相対角度の如何に拘わらず、一方のバネ受け部から背凭れアームにバネ反力を、すべり等を生じることなく確実に伝達することができる。
【００１５】
勿論、本発明は、他のスライド受圧機構として、背凭れアーム側に設けたレール部と、このレール部に沿ってスライド移動可能となるように一方のバネ受け部側に設けたスライダとからなる構成を妨げるものではない。
【００１６】
背凭れアームが単一のものである場合には、この背凭れアームの一部に設けた孔にバネ力伝達部材を貫通させるとともに、その開口周辺にスライド受圧機構を構成しておけばよい。このようにすれば、当該スライド受圧機構を背凭れアームを利用してコンパクトかつ外観に極力影響を与えないように組み込むことが容易となる。
【００１７】
本発明は、コイルスプリングを圧縮する方向がベース部材に対してほぼ変わらないものであるため、他方のバネ受け部をバネ力伝達部材に対しほぼ首振り不能に配置した別体の部材として、反力機構の安定化と反力の調整の便とを有効に高めることができる。
【００１８】
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。
【００１９】
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を備え、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。
【００２０】
【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。
【００２１】
＜構造説明＞
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。
【００２２】
具体的な構造と部品構成について図３〜図７を参照して説明する。
【００２３】
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図示しないガススプリングの上部に、ベース部材２１をその上部に有する支持体４を取付け、１本の背凭れアーム３１の前端部近傍を前記支持体４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受圧面３４１がくるように、バネ受けブラケット３４を一体に取り付けてある。
【００２４】
前記バネ受けブラケット３４は、椅子の前後方向に溝３４０を備えた下向きチャネル状をなすもので、左右の垂下壁の下面を下向き凸状に湾曲させて、当該下面を、バネ力を受ける受圧面３４１に設定している。これら背凭れアーム３１及びバネ受けブラケット３４には、バネ力伝達部材５３を前後方向に移動可能な状態で貫通させるための長穴３１０、３４６が設けてある。
【００２５】
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５１１と下バネ受け部材５２のバネ受け面５２１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、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、このバネ力伝達部材５３に下方からスライド支持部材５４、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を貫通させて、当該バネ力伝達部材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できるようにしている。ここで、スライド支持部材５４、上バネ受け部材５１及び下バネ受け部材５２には、バネ力伝達部材５３を移動不能な状態で貫通させるための丸穴が形成してある。これら両バネ受け部材５１、５２は、バネ力伝達部材５３に対して相対的に首振り動作をすることを要求されないためである。
【００２６】
スライド支持部材５４は、前記バネ受けブラケット３４と共に背凭れアーム３１と上バネ受け部材５１との間に介在して、背凭れアーム３１の後傾動作に伴い背凭れアーム３１上でバネ力が作用する部分をスライド移動させつつ上バネ受け部材５１が受けるバネ力を当該背凭れアーム３１に受圧させる本発明のスライド受圧機構５０を構成するものである。スライド支持部材５４は、下端を上バネ受け部材５１の上面に添設させ、上端に設けた突出部５４０を前記バネ受けブラケット３４の溝３４０内に前後方向へ相対移動可能に嵌め込んだ駒状のもので、突出部５４０の両側に位置するスライド支持部材５４の上面には、上向き凹状に湾曲した与圧面５４１が形成してある。この与圧面５４１は、背凭れ３が後傾するに従って、バネ力伝達部材５３の軸心上に位置するバネ受けブラケット３４の受圧面３４１が背凭れアーム３１の回転中心である背凭れアーム回転軸３２から次第に後方へ移動し、かつ高さ方向に降下しても、常に受圧面３４１の一定領域と接面した状態を保つような形状が付与されている。
【００２７】
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。この上面は、前記スライド支持部材５４を安定して添接させるために、中央を若干窪ませてある。
【００２８】
下バネ受け部材５２は、同じく鋼板を、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。
【００２９】
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。
【００３０】
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。図３〜図６においてこの操作部ＳＳは図示省略してある。
【００３１】
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５３３が伸びており、軸部５３３の下端部近傍に前記先端ねじ部５３２が形成されている。一方、ベース部材２１は、後端部近傍において四角柱状の回転止め部嵌合穴２１３およびその下方に位置する円形穴２１４を設けることで、バネ力伝達部材５３の回転止め部５３１を回転止め部嵌合穴２１３に嵌合し、後述する操作部ＳＳをねじ込む際に、このバネ力伝達部材５３が一体に回転しないように保持できるようになっており、円形穴２１４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。
【００３２】
このベース部材２１の四角柱状の回転止め部嵌合穴２１３およびその下方に位置する円形穴２１４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、スライド支持部材５４、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。
【００３３】
なお、この反力機構５は、メカ部カバーＭＣ（図１、図２参照）によって目隠しされるようにしている。メカ部カバーＭＣは、操作部ＳＳによる操作が可能なように当該操作部ＳＳを露出させるための開口、あるいは、背凭れアーム３１の後傾動作を妨げないためのスリットを対応部位に適宜有し、それ以外は上バネ受け部材５１、コイルスプリングＳＰ、下バネ受け部材５２を隠蔽することができる形状をなすもので、支持体４に固定して取り付けられる。
【００３４】
なお、以上において、上バネ受け部材５１、下バネ受け部材５２、バネ力伝達部材５３、コイルスプリングＳＰが、主として本発明の反力機構５を構成している。
【００３５】
＜動作説明＞
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。
【００３６】
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、図５はその際の反力機構５周辺の拡大図である。この時背凭れアーム３１側のバネ受けブラケット３４は背凭れアーム回転軸３２の基端部とともに略水平姿勢にあり、かつスライド支持部材５４、上バネ受け部材５１、コイルスプリングＳＰ及び下バネ受け部材５２のほぼ中央真上にあって、スライド支持部材５４の与圧面５４１はバネ受けブラケット３４の受圧面３４１の前後方向ほぼ中央部位に接触している。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、与圧面５４１と受圧面３４１が接触している部分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の基端部における延伸方向と直交する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。
【００３７】
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。
【００３８】
ここから背凭れアーム３１を後傾させていくと、受圧面３４１のうち与圧面５４１が接触している部分は、次第に背凭れアーム３１上、回転軸心から遠ざかる方向へ移動し、与圧面５４１の接触部分の高さ位置が次第に低くなっていくが、上バネ受け部材５１及び下バネ受け部材５２はコイルスプリングＳＰと共に水平方向定位置にあるため、コイルスプリングＳＰの反力の方向が常に垂直上向きであるのに対して、前記接触部分が背凭れアーム回転軸３２を中心に回転しようとする方向すなわち背凭れアーム３１の基端部の延伸方向と直交する方向は、背凭れアーム３１の後傾に伴ってその後傾角度分だけコイルスプリングＳＰの反力の方向に対してずれていくことになる。
【００３９】
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、図６はその際の反力機構５周辺の拡大図である。この時スライド支持部材５４の与圧面５４１は、バネ受けブラケット３４の受圧面３４１の後方位置に接触した状態にある。この時、前記接触部分の中心位置が回動しようとする方向すなわち当該中心位置を通り背凭れアーム３１の基端部と直交する方向は、コイルスプリングＳＰの反力の方向である垂直上向きに対して大きくずれている。
【００４０】
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、受圧面３４１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。
【００４１】
ここまでの説明で明らかなように、バネ軸伝達部材５３の取り付け角度を変えたり、背凭れアーム３１の基端部に角度をもたせる等すれば、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。
【００４２】
＜実施形態の作用効果＞
以上のように、本実施形態は、脚１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２１と、このベース部材２１に対して相対的に回動可能に配置された背凭れアーム３１と、背凭れアーム３１に反力を付与する反力機構５とを具備してなる椅子であり、前記反力機構５が、背凭れアーム３１側に備えられた上バネ受け部材５１と、一端側がベース部材２１に連結され背凭れアーム３１をこえた他端側に下バネ受け部材５２を有するバネ力伝達部材５３と、上バネ受け部材５１と下バネ受け部材５２の間に配置されたコイルスプリングＳＰとを有し、背凭れアーム３１の後傾時にコイルスプリングＳＰを圧縮可能にするとともに、背凭れアーム３１が後傾するに従って、背凭れアーム３１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ＳＰを圧縮する方向が徐々に変化していくように構成されるものである。そして、前記反力機構５のバネ力伝達部材５３をベース部材に対し首振り不能に保持し、背凭れアーム３１の後傾状態にかかわらず一方のバネ受け部５１の水平方向位置がバネ力伝達部材５３及び下バネ受け部材５２に対し相対的にほぼ変わらないようにして、背凭れアーム３１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のみがベース部材２１に対して変化し、コイルスプリングＳＰを圧縮する方向がベース部材２１に対してほぼ変わらないように構成している。
【００４３】
このため、背凭れアーム３１が後傾するに従い、コイルスプリングＳＰが圧縮されてコイルスプリングＳＰの全反力は大きくなっていくが、同時に背凭れアーム３１が回動しようとする方向に対して、コイルスプリングＳＰ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ＳＰが背凭れアーム３１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３１の後傾時におけるコイルスプリングＳＰ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具合をさまざまに設定でき、ひいては背凭れ３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。しかも、上バネ受け部材５１の水平方向位置をバネ力伝達部材５３や下バネ受け部材５２に対して相対的にほぼ変わらないようにして、背凭れアーム３１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のみが変化し、コイルスプリングＳＰを圧縮する方向がほぼ一定方向を向いているようにしたので、例えば上バネ受け部材５１の水平方向位置がバネ力伝達部材５３及び下バネ受け部材５２に対して相対的に移動し、これに伴ってコイルスプリングＳＰを圧縮する方向が変化する構成のものに比べて、背凭れ３の傾動角度と反力の増減の程度とを好適に比例させて反力を一定に保つ設計等を比較的容易に行えるようになる上に、反力機構５の各部の構成部材にスムーズな動作を付与することができ、またバネ受け部材５１、５２等に無理な力がかかることを有効に回避可能となるし、反力機構５を被覆するメカ部カバーＭＣもコイルスプリングＳＰの動作に連動する可動のものにする必要がないため定位置に確実に取り付けておくことができるようになる。
【００４４】
また、背凭れ３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３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ために、反力機構５が、背凭れアーム３１上のバネを圧縮する受圧面３４１の中心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３１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ため、背凭れ３を後傾させていくに従ってコイルスプリングＳＰが圧縮されても、背凭れアーム３１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ＳＰ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る。そして、背凭れアーム３１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、例えば、背凭れ３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設定も容易に可能なものとなる。
【００４５】
具体的な構造として、本実施形態は、反力機構５の上バネ受け部材５１をバネ力伝達部材５３にほぼ首振り不能に配置された別体の部材とし、当該上バネ受け部材５１と背凭れアーム３１との間に、背凭れアーム３１の後傾動作に伴い背凭れアーム３１上でバネ力が作用する部分をスライド移動させつつ上バネ受け部材５１が受けるバネ力を当該背凭れアーム３１に受圧させるスライド受圧機構５０を設けており、背凭れアーム３１が後傾すると、背凭れアーム３１上のバネ力が作用する部分が当該背凭れアーム３１上を次第に回転中心から遠い部位に移動することになるが、かかるスライド受圧機構により、このような部材同士が係り合った状態での相対動作を円滑に安定して行わせることができる。
【００４６】
図７はバネ受けブラケット３４及びスライド支持部材５４の拡大図である。特に、そのスライド受圧機構５０を、背凭れアーム３１側に設けた下向き凸状の受圧面３４１と、上バネ受け部材５１側に設けた上向き凹状の与圧面５４１とから構成しているため、背凭れアーム３１が後傾し、上バネ受け部材５１のベース部材２１に対する角度がほぼ変わらないのに対して、背凭れアーム３１のなす角度が漸次増大することになっても、両部材の相対角度の如何に拘わらず、上バネ受け部材５１から背凭れアーム３１にバネ反力をすべり等を生じることなく確実に伝達することができ、伝達ロスを防ぐとともに安定した確実な挙動を確保することができる。
【００４７】
また、この実施形態は、背凭れアーム３１が単一のものであるが、背凭れアーム３１の一部に設けた孔にバネ力伝達部材５３を貫通させるとともに、その開口周辺にスライド受圧機構５０を構成しているため、コンパクトで極力外部に露出しないように当該スライド受圧機構５０を組み込むことを可能にしているものである。勿論、背凭れアームが例えば２本平行に設けられるような場合にも、左右の背凭れアーム間にコイルスプリングＳＰの圧縮力を受ける部材を配置するなどすれば、この実施形態に準じた作用効果を得ることは可能である。
【００４８】
さらに、本実施形態は、コイルスプリングＳＰを圧縮する方向がベース部材２１に対してほぼ変わらないものであるため、下バネ受け部材５２をバネ力伝達部材５３に対しほぼ首振り不能に配置した別体の部材として、反力機構５の安定化と反力調整の便とを有効に高めることが可能となる。
【００４９】
また、バネ力伝達部材５３は、スライド支持部材５４、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、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がされて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することができる。
【００５０】
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ものであり、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。ただし、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。この場合は、基本的にベース部材の前端部を回転可能に取り付け、背座をリンク機構を始めとして何らかの形で連動させるだけで容易に構成することが可能である。
【００５１】
なお、本発明は、以上に示した以外にも、種々変形が可能である。
【００５２】
例えば、凹凸の関係を変えたものとして、前記スライド支持部材５４と前記バネ受けブラケット３４の代わりに、図８のようなスライド支持部材５４２およびバネ受けブラケット３４２を設けることができる。
【００５３】
スライド支持部材５４２およびバネ受けブラケット３４２は、前記スライド支持部材５４および前記バネ受けブラケット３４と同様、背凭れアーム３１と上バネ受け部材５１との間に介在して、背凭れアーム３１の後傾動作に伴い背凭れアーム３１上でバネ力が作用する部分をスライド移動させつつ上バネ受け部材５１が受けるバネ力を当該背凭れアーム３１に受圧させるスライド受圧機構を構成するものである。バネ受けブラケット３４２は、椅子の前後方向に突出部を設けた断面略Ｔ字状をなすもので、該突出部を前後方向に下向き凸状に湾曲させて、当該下面をバネ力を受ける受圧面３４３に設定している。スライド支持部材５４２は、下端を上バネ受け部材５１の上面に添設させ、上端に設けた溝部を前記バネ受けブラケット３４２の突出部に前後方向へ相対移動可能に挿み込んだチャネル状のもので、該チャネルの溝部に位置するスライド支持部材５４２の上面には、凹状に湾曲した与圧面５４３が形成してある。この与圧面５４３は、背凭れ３が後傾するに従って、バネ力伝達部材５３の軸心上に位置するバネ受けブラケット３４２の受圧面３４３が背凭れアーム３１の回転中心から次第に後方へ移動し、かつ高さ方向に降下しても、常に受圧面３４３の一定領域と接面した状態を保つよう形状が付与されている。
【００５４】
また、他の構造からなるスライド受圧機構として、図９、１０に示すように、背凭れアーム３１側に設けたレール部３４４と、このレール部３４４に沿ってスライド移動可能となるように上バネ受け部材５１側に設けたスライダ５４４とからなる構成を採用することができる。図１１はレール部３４４およびスライダ５４４の拡大図である。このスライダ５４４の上面には、平面状の与圧面５４５が形成してある。このような構成は、背凭れ３の後傾に伴って与圧面５４５がレール部３４４に沿って後方にスライド移動することにより、バネ力伝達部材５３の軸心上に位置するレール部３４４の受圧面３４５が背凭れアーム３１の回転中心から次第に後方へ移動し、かつ高さ方向に降下しても、常に受圧面３４５の一定領域と接面した状態を保つよう形状が付与されている。この受圧機構の場合、スライダ５４４がレール部３４４に沿って後方にスライド移動する際、スライダ５４４のなす角度が上バネ受け部材５１に対して相対的に変化するが、上バネ受け部材５１の上部とスライダ５４４が、半円柱状のスライダ回転部５４６により回動可能に保持されているため、スライダ５４４はレール部３４４に沿って安定してスライド移動することができる。
【００５５】
【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な構成を、上下のバネ受け部を首振りさせることなく実現したので、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簡単な構成で有効に高めることが可能となる。
さらに、本発明の椅子は、反力機構の一方のバネ受け部がバネ力伝達部材にほぼ首振り不能に配置された別体の部材であり、当該一方のバネ受け部と背凭れアームとの間に、背凭れアームの後傾動作に伴い背凭れアーム上でバネ力が作用する部分をスライド移動させつつ一方のバネ受け部が受けるバネ力を当該背凭れアームに受圧させるスライド受圧機構を設けている。背凭れアームが後傾すると、背凭れアーム上のバネ力が作用する部分が当該背凭れアーム上を次第に回転中心から遠い部位に移動することになるが、かかるスライド受圧機構を設けているので、このような部材同士が係り合った状態での相対動作を円滑に安定して行わせることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態を示す側面図。
【図２】同実施形態の背面図。
【図３】同実施形態の部分側面図。
【図４】図３に対応した作用説明図。
【図５】図３の要部拡大断面図。
【図６】図４の要部拡大断面図。
【図７】同実施形態の要部分解斜視図。
【図８】同実施形態の変形例を示す図。
【図９】本発明の他の実施形態を示す要部拡大側断面図。
【図１０】図９に対応した作用説明図。
【図１１】図９に対応した要部分解斜視図。
【符号の説明】
１…脚
１１…脚羽根
１２…脚支柱
２…座
２１…ベース部材
３…背凭れ
３１…背凭れアーム
３２…背凭れアーム回転軸
３４、３４２…バネ受けブラケット
３４１、３４３、３４５…受圧面
３４４…レール部
５…反力機構
５１…上バネ受け部材
５２…下バネ受け部材
５３…バネ力伝達部材
５３１…回転止め部
５３２…先端ねじ部
５４、５４２…スライド支持部材
５４１、５４３、５４５…与圧面
５４４…スライダ
５４６…スライダ回転部
ＳＰ…コイルスプリング[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 synchro tilt and back-only tilt have been developed. Typically, as shown in Patent Document 1, a base on which a leg or the like is attached is disclosed. In the case of the back seat sync tilt, the front end of the base member is slidably and rotatably supported. A seat having a rear end portion rotatably supported in the vicinity of the base end portion of the backrest arm, and a spring connected to the lower portion of the seat so as to be interposed between two points whose relative distance changes with tilting In the case of tilting only in the back, relative to 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 in the lower rear part of the seat as the backrest tilts Has a spring connected so as to be interposed between two points of varying distance There has been known was. And these chairs are configured to always return to a standing posture by applying a tilting force that tilts the backrest or seat to a standing posture even when the backrest fixed to the backrest arm is tilted backward. Has been.
[0003]
[Patent Document 1]
JP-A-7-255562
[0004]
[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.
[0005]
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.
[0006]
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.
[0007]
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.
[0008]
[Means for Solving the Problems]
  In order to easily solve the above problems, a chair according to the present invention is attached to an upper part of a leg and has a base member having a seat on the upper side, and is rotatable relative to the base member. A backrest arm arranged and a reaction force mechanism for applying a reaction force to the backrest arm.RThe reaction force mechanism has one spring receiving portion provided on the backrest arm side, and a spring force transmission member having one end connected to the base member and the other spring receiving portion on the other end side beyond the backrest arm. And a coil spring disposed between one spring receiving portion and the other spring receiving portion, the coil spring can be compressed when the backrest arm is tilted backward, and 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 where the spring force acts on the backrest arm is about to rotate. is there. The spring force transmitting member of the reaction force mechanism is held so as not to swing with respect to the base member, and the horizontal position of one of the spring receiving portions regardless of the back tilt state of the backrest arm The coil spring is compressed by changing only the tangential direction in which the portion on which the spring force is applied on the backrest arm is about to rotate relative to the base member so that it does not substantially change relative to the spring receiving portion. The direction to do is not changed with respect to the base member.And one spring receiving portion of the reaction force mechanism is a separate member arranged in a substantially non-oscillating manner on the spring force transmitting member, and between the one spring receiving portion and the backrest arm, A slide pressure receiving mechanism is provided for receiving the spring force received by one of the spring receiving portions while sliding the portion where the spring force acts on the backrest arm in accordance with the backward tilting operation of the backrest arm.It is characterized by that.
[0009]
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. In addition, the horizontal position of one of the spring receiving portions is not substantially changed relative to the spring force transmitting member or the other spring receiving portion, so that the portion where the spring force is acting on the backrest arm rotates. Since only the tangential direction to be moved is changed and the direction in which the coil spring is compressed is directed to a substantially constant direction, for example, the horizontal position of the spring receiving portion is set to the spring force transmitting member and the other spring receiving portion. Compared to the configuration in which the direction of compressing the coil spring is changed relative to this, the tilt angle of the backrest and the degree of increase / decrease of the reaction force are suitably proportional to each other. It is relatively easy to keep the design constant, etc., and it is possible to give smooth operation to the components of each part of the reaction force mechanism, and it is effective to apply excessive force to the spring receiving part etc. It becomes possible to avoid and reaction machine Cover covering also be able to be securely attached in place since it is not necessary to those of the movable interlocked with the operation of the coil spring to.
[0010]
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.
[0011]
  Further, in the chair according to the present invention, one spring receiving portion of the reaction force mechanism is a separate member disposed on the spring force transmitting member so as not to swing, the one spring receiving portion and the backrest arm, A slide pressure receiving mechanism that causes the backrest arm to receive the spring force received by one spring receiving portion while sliding the portion where the spring force acts on the backrest arm in accordance with the backward tilting motion of the backrest arm Provided. When the backrest arm tilts backward, the part on which the spring force acts on the backrest arm will gradually move on the backrest arm to a site far from the center of rotation, but since such a slide pressure receiving mechanism is provided, Relative motion in a state where such members are engaged with each other can be performed smoothly and stably.
[0012]
  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.
[0013]
  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. In the case where the back reaction force is increased and the vehicle is further tilted backward from a position tilted back to some extent, it is possible to moderate the increase in the back reaction force.
[0014]
As a preferable slide pressure receiving mechanism, a mechanism constituted by a downward convex pressure receiving surface provided on the backrest arm side and an upward concave pressurizing surface provided on one spring receiving portion side can be mentioned. That is, when the backrest arm is tilted backward, the angle of the one spring support portion with respect to the base member is not substantially changed, whereas the angle formed by the backrest arm gradually increases. In this case, the spring reaction force can be reliably transmitted from one spring receiving portion to the backrest arm regardless of the relative angle between the two members without causing a slip or the like.
[0015]
Of course, the present invention includes, as another slide pressure receiving mechanism, a rail portion provided on the backrest arm side and a slider provided on one spring receiving portion side so as to be slidable along the rail portion. It does not interfere with the configuration.
[0016]
When the backrest arm is a single arm, the spring force transmission member may be passed through a hole provided in a part of the backrest arm, and a slide pressure receiving mechanism may be configured around the opening. If it does in this way, it will become easy to incorporate the said slide pressure receiving mechanism using a backrest arm so that it may be compact and may have the least influence on an external appearance.
[0017]
In the present invention, since the direction in which the coil spring is compressed is substantially the same as that of the base member, the other spring receiving portion is separated from the spring force transmission member as a separate member disposed so as not to swing. The stabilization of the force mechanism and the convenience of adjusting the reaction force can be enhanced effectively.
[0018]
In order to make the system more compact, it is conceivable that the reaction force mechanism has a configuration in which 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.
[0019]
The reaction mechanism further includes a seat portion that does not move in conjunction with a backward tilting motion of the backrest arm, and a backrest arm that is rotatably pivoted below the base member. With the arrangement, the sitting system when tilting backward can be greatly improved while the system of the entire chair is a tilt mechanism with only a backrest and is simple and inexpensive.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0021]
<Description of structure>
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
[0022]
A specific structure and component configuration will be described with reference to FIGS.
[0023]
That is, this chair is provided with a support 4 having a base member 21 on the upper part of a gas spring (not shown) 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 one backrest arm 31 is rotatably attached to the support 4 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. In addition, a spring receiving bracket 34 is integrally attached to the backrest arm 31 so that the pressure receiving surface 341 is located at a position corresponding to the lower vicinity of the rear end portion of the base member 21.
[0024]
The spring receiving bracket 34 has a downward channel shape with a groove 340 in the front-rear direction of the chair. The lower surface of the left and right hanging walls is curved downward and the pressure receiving surface receives the spring force. 341 is set. The backrest arm 31 and the spring receiving bracket 34 are provided with elongated holes 310 and 346 for allowing the spring force transmitting member 53 to pass through in a state where the spring force transmitting member 53 is movable in the front-rear direction.
[0025]
Next, the coil spring SP is arranged so as to be sandwiched between the spring receiving surface 511 of the upper spring receiving member 51 and the spring receiving surface 521 of the lower spring receiving member 52, and the screw is provided near the rear end portion of the base member 21 and at the lower end portion. The spring force transmission member 53 formed of is attached to the base member 21 so as not to swing and rotate. The slide support member 54 and the upper spring receiving member are attached to the spring force transmission member 53 from below. 51, the coil spring SP and the lower spring receiving member 52 are penetrated, and the operation portion SS is screwed and fixed to the lower end portion of the 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 so that the general reaction force of the backrest 3 can be adjusted. Here, the slide support member 54, the upper spring receiving member 51, and the lower spring receiving member 52 are formed with round holes for allowing the spring force transmitting member 53 to pass therethrough in a non-movable state. This is because these spring receiving members 51 and 52 are not required to swing relative to the spring force transmission member 53.
[0026]
The slide support member 54 is interposed between the backrest arm 31 and the upper spring support member 51 together with the spring support bracket 34, and a spring force acts on the backrest arm 31 as the backrest arm 31 is tilted backward. The slide pressure receiving mechanism 50 of the present invention is configured to cause the backrest arm 31 to receive the spring force received by the upper spring receiving member 51 while sliding the portion to be moved. The slide support member 54 has a lower end attached to the upper surface of the upper spring receiving member 51, and a projection 540 provided at the upper end is fitted into the groove 340 of the spring receiving bracket 34 so as to be relatively movable in the front-rear direction. On the upper surface of the slide support member 54 located on both sides of the projecting portion 540, a pressurizing surface 541 curved in an upward concave shape is formed. As the backrest 3 tilts backward, the pressurizing surface 541 has a backrest arm rotation shaft in which the pressure receiving surface 341 of the spring receiving bracket 34 positioned on the axial center of the spring force transmission member 53 is the center of rotation of the backrest arm 31. The shape is given so that the state where the pressure receiving surface 341 is always in contact with a certain region is maintained even if the rearward movement gradually moves from 32 and descends in the height direction.
[0027]
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. The upper surface is slightly depressed at the center in order to stably contact the slide support member 54.
[0028]
Similarly, 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.
[0029]
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.
[0030]
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. 3 to 6, the operation unit SS is not shown.
[0031]
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 533 extends downward from the center portion of the lower surface, and the lower end portion of the shaft portion 533. The tip screw portion 532 is formed in the vicinity. On the other hand, the base member 21 is provided with a quadrangular columnar rotation stopper fitting hole 213 and a circular hole 214 positioned therebelow in the vicinity of the rear end portion, so that the rotation stopper 531 of the spring force transmission member 53 is prevented from rotating. The spring force transmission member 53 can be held so as not to rotate integrally when the operation portion SS, which will be described later, is screwed into the fitting hole 213, and the spring force is provided by having the circular hole 214. The swing of the transmission member 53 can be prevented.
[0032]
The spring force transmission member 53 is penetrated from the upper side through the square columnar rotation stopper fitting hole 213 of the base member 21 and the circular hole 214 located therebelow so as not to rotate, and at the same time, the spring force transmission member 53. From below, the slide support member 54, the upper spring receiving member 51, the coil spring SP, and the lower spring receiving member 52 are penetrated, and the operating portion SS is screwed into the tip screw portion 532, so that the spring force transmission member 53 penetrates. All members 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.
[0033]
The reaction force mechanism 5 is hidden by a mechanical cover MC (see FIGS. 1 and 2). The mechanical unit cover MC appropriately has an opening for exposing the operation unit SS so that the operation unit SS can be operated or a slit for preventing the backrest arm 31 from tilting backward in a corresponding portion. Other than that, the upper spring receiving member 51, the coil spring SP, and the lower spring receiving member 52 can be concealed, and are fixedly attached to the support 4.
[0034]
In the above description, the upper spring receiving member 51, the lower spring receiving member 52, the spring force transmission member 53, and the coil spring SP mainly constitute the reaction force mechanism 5 of the present invention.
[0035]
<Description of operation>
The operation according to the above configuration will be specifically described below.
[0036]
FIG. 3 shows a posture in which the backrest 3 stands up most, and FIG. 5 is an enlarged view around the reaction force mechanism 5 at that time. At this time, the spring receiving bracket 34 on the backrest arm 31 side is in a substantially horizontal posture together with the base end portion of the backrest arm rotating shaft 32, and the slide support member 54, the upper spring receiving member 51, the coil spring SP, and the lower spring receiving member. The pressure-applying surface 541 of the slide support member 54 is in contact with a substantially central portion in the front-rear direction of the pressure-receiving surface 341 of the spring receiving bracket 34. The coil spring SP is in a compressed state at least so as to generate a spring reaction force that can hold the backrest arm 31 in the upright position. At this time, the direction of the spring force, that is, the upper and lower sides passing through the center of the coil spring SP. Is the tangential direction in which the portion where the pressure-applying surface 541 and the pressure-receiving surface 341 are in contact with each other is rotated by the reaction force of the coil spring SP, that is, the extending direction at the base end portion of the backrest arm rotating shaft 32. It is oriented in the perpendicular upward direction perpendicular to each other, and these two directions substantially coincide.
[0037]
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.
[0038]
When the backrest arm 31 is tilted backward from here, the portion of the pressure receiving surface 341 that is in contact with the pressure applying surface 541 gradually moves on the backrest arm 31 in a direction away from the rotation axis, and the pressure applying surface 541 is moved. However, since the upper spring receiving member 51 and the lower spring receiving member 52 are in a horizontal position together with the coil spring SP, the direction of the reaction force of the coil spring SP is always vertical. The direction in which the contact portion tries to rotate around the backrest arm rotation shaft 32, that is, the direction orthogonal to the extending direction of the base end portion of the backrest arm 31, is the rear of the backrest arm 31. With the inclination, the coil spring SP is displaced from the direction of the reaction force by the inclination angle thereafter.
[0039]
FIG. 4 shows a posture in which the backrest 3 is largely inclined backward, and FIG. 6 is an enlarged view of the periphery of the reaction force mechanism 5 at that time. At this time, the pressurizing surface 541 of the slide support member 54 is in contact with the rear position of the pressure receiving surface 341 of the spring receiving bracket 34. At this time, the direction in which the center position of the contact portion is about to rotate, that is, the direction passing through the center position and perpendicular to the base end portion of the backrest arm 31 is perpendicular to the direction of the reaction force of the coil spring SP. Is greatly deviated.
[0040]
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 pressure receiving surface 341 are conceptually represented.
[0041]
As is apparent from the above description, if the mounting angle of the spring shaft transmission member 53 is changed, or if the base end portion of the backrest arm 31 is angled, the backrest arm 31 is tilted backward. 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.
[0042]
<Effects of Embodiment>
As described above, in this embodiment, the base member 21 that is attached to the upper portion of the leg 1 and has a seat portion on the upper side, and the backrest arm that is disposed to be rotatable relative to the base member 21. 31 and a reaction force mechanism 5 that applies a reaction force to the backrest arm 31, and the reaction force mechanism 5 includes an upper spring receiving member 51 provided on the backrest arm 31 side, One end side is connected to the base member 21 and is disposed between the upper spring receiving member 51 and the lower spring receiving member 52, and a spring force transmitting member 53 having a lower spring receiving member 52 on the other end side beyond the backrest arm 31. A portion having a coil spring SP, which allows the coil spring SP to be compressed when the backrest arm 31 is tilted backward, and where the spring force acts on the backrest arm 31 as the backrest arm 31 tilts backward. Let's turn Relative to the tangential direction, in which direction to compress the coil spring SP is configured to change gradually. The spring force transmission member 53 of the reaction force mechanism 5 is held so as not to swing with respect to the base member, and the horizontal position of one spring receiving portion 51 is the spring force transmission regardless of the back tilt state of the backrest arm 31. Only the tangential direction in which the portion on which the spring force is applied on the backrest arm 31 tries to rotate is rotated relative to the base member 21 so as not to change relatively with respect to the member 53 and the lower spring receiving member 52. The direction in which the coil spring SP is compressed is substantially the same as that of the base member 21.
[0043]
For this reason, as the backrest arm 31 tilts backward, the coil spring SP is compressed and the total reaction force of the coil spring SP increases, but at the same time, with respect to the direction in which the backrest arm 31 tries to rotate, Since the direction of the total reaction force of the coil spring SP is gradually shifted, the magnitude of the effective component of the reaction force that the coil spring SP tries to return the backrest arm 31 to the standing posture increases or decreases. By setting the degree of compression and the direction of displacement of the coil spring SP when the backrest arm 31 is tilted backward, various changes in the reaction force that the coil spring SP tries to return the backrest arm 31 to the standing posture Thus, without changing the basic system for tilting the backrest 3, the degree of freedom in designing the seating comfort of the chair can be increased. In addition, a portion where the spring force is acting on the backrest arm 31 so that the horizontal position of the upper spring receiving member 51 is not substantially changed relative to the spring force transmitting member 53 and the lower spring receiving member 52. Since only the tangential direction in which the coil springs are to be rotated is changed and the direction in which the coil spring SP is compressed is directed to a substantially constant direction, the horizontal position of the upper spring receiving member 51 is, for example, the spring force transmitting member 53 and The tilt angle of the backrest 3 and the degree of increase / decrease of the reaction force are compared with those of a configuration that moves relative to the lower spring receiving member 52 and changes the direction in which the coil spring SP is compressed accordingly. A design that keeps the reaction force constant proportionally can be performed relatively easily, and a smooth operation can be imparted to the constituent members of each part of the reaction force mechanism 5, and the spring receiving member 51. , 52 It is possible to effectively avoid applying an excessive force to the actuator, and the mechanical cover MC that covers the reaction force mechanism 5 does not need to be movable in conjunction with the operation of the coil spring SP, so that it can be securely in place. It can be attached.
[0044]
In addition, in order to set the degree of increase of the reaction force when the backrest 3 is largely tilted backward with respect to the initial reaction force of the backrest when the backrest 3 is in the vicinity of the standing posture. The backrest arm 31 stands up most at an angle between the tangential direction in which the center of the pressure receiving surface 341 that compresses the spring on the backrest arm 31 and the direction in which the spring is compressed is formed. Since it changes so that it may increase as it leans backward from posture, even if the coil spring SP is compressed as the backrest 3 is inclined backward, it tries to return the backrest arm 31 to the standing posture. The effective component of the reaction force can be prevented from becoming as large as the degree of compression of the coil spring SP. And, for example, when the backrest 3 is tilted backward by setting the change in the angle between the rotational tangent direction of the backrest arm 31 and the spring direction, the backrest reaction force is almost linear in the vicinity of the standing position. If the position is increased and further tilted backward from a position tilted to some extent, it is possible to easily set the backrest reaction force to increase gradually.
[0045]
As a specific structure, in the present embodiment, the upper spring receiving member 51 of the reaction force mechanism 5 is a separate member that is disposed on the spring force transmitting member 53 so as not to swing. The backrest arm 31 receives the spring force received by the upper spring receiving member 51 while sliding the portion where the spring force acts on the backrest arm 31 in accordance with the backward tilting operation of the backrest arm 31 between the backrest arm 31 and the backrest arm 31. When the backrest arm 31 tilts backward, the portion on which the spring force acts is gradually moved on the backrest arm 31 to a position far from the center of rotation. However, such a slide pressure receiving mechanism can smoothly and stably perform the relative operation in a state where such members are engaged with each other.
[0046]
FIG. 7 is an enlarged view of the spring receiving bracket 34 and the slide support member 54. In particular, the slide pressure receiving mechanism 50 includes a downward convex pressure receiving surface 341 provided on the backrest arm 31 side and an upward concave pressure applying surface 541 provided on the upper spring receiving member 51 side. Even though the angle of the backrest arm 31 gradually increases while the angle of the backrest arm 31 tilts and the angle of the upper spring receiving member 51 with respect to the base member 21 does not substantially change, the relative angle of both members Regardless of the above, it is possible to reliably transmit the spring reaction force from the upper spring receiving member 51 to the backrest arm 31 without slipping, and to prevent transmission loss and ensure a stable and reliable behavior. it can.
[0047]
In this embodiment, the backrest arm 31 is single, but the spring force transmission member 53 is passed through a hole provided in a part of the backrest arm 31, and the slide pressure receiving mechanism 50 is provided around the opening. Therefore, the slide pressure receiving mechanism 50 can be incorporated so as not to be exposed to the outside as much as possible. Of course, even when two backrest arms are provided in parallel, for example, if a member that receives the compression force of the coil spring SP is arranged between the left and right backrest arms, the operational effects according to this embodiment are achieved. It is possible to get
[0048]
Further, in the present embodiment, the direction in which the coil spring SP is compressed is substantially the same as that of the base member 21. Therefore, the lower spring receiving member 52 is arranged so as not to swing with respect to the spring force transmitting member 53. As a body member, it is possible to effectively increase the stability of the reaction force mechanism 5 and the convenience of reaction force adjustment.
[0049]
The spring force transmission member 53 is disposed so as to penetrate the slide support member 54, the upper spring receiving member 51, the coil spring SP, the lower spring receiving member 52, and the operation unit SS. Thus, a compact system can be obtained, and troubles such as the coil spring SP being detached from the upper and lower spring receiving members 51 and 52 even when an unexpected force is applied can be prevented.
[0050]
Further, the base member 21 and the seat 2 and the backrest arm 31 are not provided with an interlocking mechanism. 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 31 does not move. By disposing the reaction force mechanism 5 behind the swivel arm rotation shaft 32, the entire chair system can be used as a tilt mechanism only for the backrest, and the seating comfort when tilting backward is greatly improved while being simple and inexpensive. Can do. However, the present invention is not limited to this, and the present invention can be applied to a back seat synchro tilt mechanism in which the motion of the back seat is interlocked, or the reaction force mechanism 5 can be arranged in front of the seat. In this case, it is basically possible to easily configure the base member by simply attaching the front end portion of the base member in a rotatable manner and interlocking the back seat in some form including a link mechanism.
[0051]
In addition to the above, the present invention can be variously modified.
[0052]
For example, a slide support member 542 and a spring support bracket 342 as shown in FIG. 8 can be provided in place of the slide support member 54 and the spring support bracket 34 as the relationship between the unevennesses.
[0053]
Similar to the slide support member 54 and the spring support bracket 34, the slide support member 542 and the spring support bracket 342 are interposed between the backrest arm 31 and the upper spring support member 51, and are tilted backward. The slide pressure receiving mechanism is configured to cause the backrest arm 31 to receive the spring force received by the upper spring receiving member 51 while sliding the portion on which the spring force acts on the backrest arm 31 in accordance with the operation. The spring receiving bracket 342 has a substantially T-shaped cross section provided with a projecting portion in the front-rear direction of the chair. The pressure receiving surface receives the spring force by curving the projecting portion downward and convex in the front-rear direction. 343. The slide support member 542 has a channel shape in which a lower end is attached to the upper surface of the upper spring receiving member 51 and a groove portion provided at the upper end is inserted into the protruding portion of the spring receiving bracket 342 so as to be relatively movable in the front-rear direction. Thus, a pressurizing surface 543 curved in a concave shape is formed on the upper surface of the slide support member 542 located in the groove portion of the channel. As the backrest 3 tilts backward, the pressure receiving surface 543 moves the pressure receiving surface 343 of the spring receiving bracket 342 located on the axis of the spring force transmitting member 53 gradually rearward from the center of rotation of the backrest arm 31, In addition, a shape is imparted so as to always maintain a state in contact with a certain region of the pressure-receiving surface 343 even when it is lowered in the height direction.
[0054]
Also, as a slide pressure receiving mechanism having another structure, as shown in FIGS. 9 and 10, a rail portion 344 provided on the backrest arm 31 side and an upper spring so as to be slidable along the rail portion 344. A configuration including a slider 544 provided on the receiving member 51 side can be employed. FIG. 11 is an enlarged view of the rail portion 344 and the slider 544. A flat pressure surface 545 is formed on the upper surface of the slider 544. In such a configuration, the pressure receiving surface 545 slides rearward along the rail portion 344 as the backrest 3 tilts backward, so that the pressure received by the rail portion 344 positioned on the axial center of the spring force transmission member 53 is obtained. Even when the surface 345 gradually moves rearward from the center of rotation of the backrest arm 31 and descends in the height direction, the shape is given so as to always maintain a state in contact with a certain region of the pressure receiving surface 345. In the case of this pressure receiving mechanism, when the slider 544 slides rearward along the rail portion 344, the angle formed by the slider 544 changes relative to the upper spring receiving member 51. Since the slider 544 is rotatably held by the semi-cylindrical slider rotating portion 546, the slider 544 can stably slide along the rail portion 344.
[0055]
【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 the configuration that gradually shifts is realized without swinging the upper and lower spring receiving parts, the design of the sitting comfort of the chair is possible without changing the basic system for tilting the backrest. The degree can be effectively increased with a simple configuration.
  Furthermore, the chair of the present invention is a separate member in which one spring receiving portion of the reaction force mechanism is arranged on the spring force transmitting member so as not to swing, and the one spring receiving portion and the backrest arm A slide pressure receiving mechanism is provided to allow the backrest arm to receive the spring force received by one spring receiving part while sliding the part where the spring force acts on the backrest arm with the back tilting action of the backrest arm. ing. When the backrest arm tilts backward, the part on which the spring force acts on the backrest arm will gradually move on the backrest arm to a site far from the center of rotation, but since such a slide pressure receiving mechanism is provided, Relative motion in a state where such members are engaged with each other can be performed smoothly and stably.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of the present invention.
FIG. 2 is a rear view of the embodiment.
FIG. 3 is a partial side view of the embodiment.
FIG. 4 is an operation explanatory diagram corresponding to FIG. 3;
5 is an enlarged cross-sectional view of a main part of FIG.
6 is an enlarged cross-sectional view of a main part of FIG.
FIG. 7 is an exploded perspective view of main parts of the embodiment.
FIG. 8 is a view showing a modification of the embodiment.
FIG. 9 is an enlarged side cross-sectional view of a main part showing another embodiment of the present invention.
FIG. 10 is an operation explanatory diagram corresponding to FIG. 9;
11 is an exploded perspective view of a main part corresponding to FIG. 9. FIG.
[Explanation of symbols]
1 ... Leg
11 ... Leg feathers
12 ... Leg prop
2 ... za
21 ... Base member
3 ... Backrest
31 ... Backrest arm
32 ... Back arm rotation axis
34, 342 ... Spring support bracket
341, 343, 345 ... pressure receiving surface
344 ... Rail part
5 ... Reaction force mechanism
51. Upper spring receiving member
52 ... Lower spring receiving member
53. Spring force transmitting member
531: Anti-rotation part
532 ... Tip screw part
54, 542 ... Slide support member
541, 543, 545 ... pressurized surface
544 ... Slider
546 ... Slider rotating part
SP ... Coil spring

Claims

A base member attached to the upper part of the leg and having a seat on the upper side, a backrest arm disposed so as to be rotatable relative to the base member, and a reaction force for applying a reaction force to the backrest arm Ri name and and a mechanism,
The reaction force mechanism includes one spring receiving portion provided on the backrest arm side, and a spring force transmission member having one end connected to the base member and the other spring receiving portion on the other end over the backrest arm. The coil spring disposed between the one spring receiving portion and the other spring receiving portion, the coil spring can be compressed when the backrest arm is tilted backward, and 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 where the spring force is acting on the backrest arm is about to rotate,
The spring force transmission member of the reaction force mechanism is held so as not to swing with respect to the base member, and the horizontal position of one spring receiving portion is the spring force transmission member and the other spring receiver regardless of the back tilt state of the backrest arm. The direction in which only the tangential direction in which the portion where the spring force is acting on the backrest arm tries to rotate is changed with respect to the base member so that the coil spring is compressed. Is configured so as not to change substantially with respect to the base member ,
One spring receiving part of the reaction force mechanism is a separate member that is disposed on the spring force transmission member so as not to swing, and the backrest arm is located between the one spring receiving part and the backrest arm. A chair provided with a slide pressure receiving mechanism that receives a spring force received by one of the spring receiving portions while sliding a portion on which the spring force acts on the backrest arm with a tilting operation. .

The reaction mechanism increases the angle between the tangential direction in which the action point that compresses 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. The chair according to claim 1, wherein the chair is changed so as to become.

Slide receiving mechanism, and a downward convex pressure receiving surface provided on the backrest arm, according to claim 1 or 2, characterized in that it is composed of a pressurizing surface of the upward concave provided on one of the spring receiving portion Chairs.

The slide pressure receiving mechanism comprises a rail portion provided on the backrest arm side and a slider provided on one spring receiving portion side so as to be slidable along the rail portion. Item 1. The chair according to item 1 or 2 .

The backrest arm is a single one, and the spring force transmission member is passed through a hole provided in a part of the backrest arm, and a slide pressure receiving mechanism is formed around the opening. The chair according to claim 1, 2, 3 or 4 .

The chair according to claim 1, 2, 3, 4, or 5, wherein the other spring receiving portion is a separate member disposed so as not to swing with respect to the spring force transmission member.

The chair according to claim 6 , wherein the spring force transmission member of the reaction force mechanism is disposed so as to penetrate the inside of the coil spring.

Equipped with a seat that does not move in conjunction with the back tilting action of the backrest arm, and a backrest arm that is pivotally fixed to the bottom of the base member, and the reaction force mechanism is located behind the rotation axis of the backrest arm The chair according to claim 1 , 2, 3, 4, 5, 6 or 7 .