JP2005034290A

JP2005034290A - Seat structure of chair

Info

Publication number: JP2005034290A
Application number: JP2003198998A
Authority: JP
Inventors: Hiroshi Masunaga; 浩益永
Original assignee: Okamura Corp
Current assignee: Okamura Corp
Priority date: 2003-07-18
Filing date: 2003-07-18
Publication date: 2005-02-10
Anticipated expiration: 2023-07-18
Also published as: JP4238081B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a comfortable seat structure without making a sitting person feel pressure or uncomfortable on the back of thighs. <P>SOLUTION: A seat frame 1 in the seat structure of a chair having a net member 3 stretched over the top of the seat frame 1 consists of a frame-like rigid outer peripheral part 2 and a cushion material support part 10 extending inward in the horizontal direction from the inner edge 2e of the outer peripheral part 2 in the front. A thick cushion material 8 facing in the left/right directions is fixed on the cushion material support part, and a top 8a of the cushion material 8 is made to project upward from a top 2a of the outer peripheral part 2 and the net member 3 is stretched over tops of both the cushion material 8 and the outer peripheral part 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、座枠にネット部材を張設した椅子の座構造に関する。
【０００２】
【従来の技術】
座枠に、高張力のプラスチック材等よりなる弾性変形可能なネット部材または多孔性シート部材（以下、本明細書においては、多孔性シート部材を含めて「ネット部材」と称する）の周縁部を取付けた椅子の座構造は公知である。
前記座枠は、一般に剛質であって、通常、ほぼ角形断面をなし、ネット部材の周縁部を支持する上面は、概ね平坦である。
ネット部材の周縁部は、座枠の上面全体にわたって当接重合されており、ネット部材に着座者の荷重が掛かると、ネット部材は撓んで、座枠の上面およびその内周角部に強く当接する。
そのため、剛質の上面およびその内周角部が着座者の太ももの後側に強く当り、圧迫感とともに、不快感を与える。
特に、ネット部材の周辺部が、十分な張力をもって均一に止着されていない場合は、ネット部材の前記撓みが大きく、着座者の前記圧迫感と不快感が増大する。
【０００３】
これに対処して、本願出願人は、座枠のうち、着座者の太ももの後側が当接する上面後方に弾性変形する張出片を設けるとともに、座枠の下側に締付枠を取付け、この締付枠をもってネット部材に大きな張力をもたせることにより、前記圧迫感等を減少させる発明を行った（特許文献１，２，３）。
一方、座枠の上面の一部にクッション材を埋設した椅子も提案されている（特許文献４）。
【０００４】
【特許文献１】
特願２００２−２１３４５０（請求項１参照）
【特許文献２】
特願２００２−２１３４５１（図４，図５参照）
【特許文献３】
特願２００２−２８１５５２（請求項１、図７参照）
【特許文献４】
特表平８−５０７９３５（ＦＩＧ．３３参照）
【０００５】
【発明が解決しようとする課題】
前記特許文献４に記載されるものは、クッション材を使用しているため、前記圧迫感等がある程度は緩和されるものの、座枠が本質的に弾性変形に乏しいため、未だ、十分には満足しうるものではない。
本発明は、本願出願人が前記特許文献１，２，３において提案した発明の改良に係るものであり、着座者が背凭れを後方に傾斜させた場合、あるいは前屈みの姿勢をとった場合などにおいても、太ももの後側に、可及的に圧迫感や不快感を与えず、座り心地が良好である椅子の座構造を提供することを目的とする。
【０００６】
【課題を解決するための手段】
本発明によると、上記課題は、次のようにして解決される。
（１）座枠の上面にネット部材を張設した椅子の座構造において、座枠を、枠状の剛質な外周部と、前部の外周部の内側縁から内方に向けて、水平方向に延設したクッション材支持部とにより形成し、前記クッション材支持部上に左右方向を向く肉厚のクッション材を固着するとともに、クッション材の上面を外周部の上面よりも上方に突出させ、かつクッション材と外周部の両者の上面にネット部材を張設した椅子の座構造とする。
【０００７】
（２）上記（１）項において、前記クッション材支持部を、外周部の上面より低位置において、水平方向に延設させる。
【０００８】
（３）上記（１）項または（２）項において、前記クッション材支持部を、肉薄とし、上下方向に弾性変形可能とする。
【０００９】
（４）上記（３）項において、前記クッション材支持部を、その後縁から前方を向く複数の切込みスリットを設け、隣接する切込みスリット間に、弾性的に下傾しうる可撓性舌片を形成する。
【００１０】
（５）上記（４）項において、前記複数の可撓性舌片のうち、左右方向の中央に位置するものほど、他の可撓性舌片よりも漸次長さの大きいものとする。
【００１１】
（６）上記（４）項または（５）項において、前記切込みスリットの奥端に、切込みが進行するのを防止するための停止孔を設ける。
【００１２】
【発明の実施の形態】
図１は、本発明の一実施形態の座構造を備える椅子（Ａ）の側面図である。
図２は、図１における座（Ｂ）の下方斜視図、図３は、同じく分解斜視図である。
【００１３】
座（Ｂ）は、閉結構造とした方形枠状の座枠（１）の外周部（２）の上面（２ａ）に、高張力プラスチック等のネット部材（３）の周縁部（３ａ）を重合した後、この周縁部（３ａ）を下方へ折り曲げて、座枠（１）の外周部（２）の上面（２ａ）および外側面（２ｂ）に重合し、さらに外周部（２）の下面（２ｃ）に沿って内方へ折り曲げ、この内向折曲げ部の下面に、座枠（１）とほぼ同様な閉結構造の方形枠状をなす締付枠（４）を重合し、締付枠（４）の各所に穿設した通孔（５）の下方より挿入したボルト（６）を、座枠（１）の下面（２ｃ）における対応箇所に穿設したねじ孔（７）へ螺合することにより、ネット部材（３）の内向折返し部を、座枠（１）の下面（２ｃ）に止着して形成されている。
【００１４】
座枠（１）の前部（２ｄ）の上面には、クッション材（８）が設けられるとともに、後記するように、ネット部材（３）に充分な張力をもたせるために、ネット部材（３）の周縁部（３ａ）と座枠（１）の外側面（２ｂ）間には、縁材（９）が圧入される。
【００１５】
図４は、枠材（１）とクッション材（８）の上方分解斜視図、図５は、図２におけるＶ〜Ｖ線拡大縦断面図である。
【００１６】
本発明における座枠（１）は、硬質プラスチックもしくは適宜の金属から形成され、肉厚の剛質に形成された方形枠状の外周部（２）と、前部（２ｄ）の外周部（２）の内側縁（２ｅ）から内方に向けて、外周部（２）の上面（２ａ）より低位置において、水平方向に延設された肉薄のクッション材支持部（１０）とよりなる。
【００１７】
前記クッション材支持部（１０）には、その後縁から前方を向く複数の切込みスリット（１１）が設けられ、隣接する切込みスリット（１１）（１１）間には、弾性的に下傾しうる可撓性舌片（１２）が形成されている。
【００１８】
可撓性舌片（１２）の可撓性を所望のものとするために、その厚さを、先端方向へ向かって、漸次小とすることもある。なお、切込みスリット（１１）の奥端には、切込みの進行を防止するために、その幅より大径の円状の停止孔（１３）を設けてある。
【００１９】
各可撓性舌片（１２）の先端は、図５に示すように、クッション材（８）が移動して落下するのを防止するため、上方に折り曲げられて落下防止片（１４）が形成され、その先端には、補強のため膨出部（１５）が付設されている。
【００２０】
前記可撓性舌片（１２）は、着座者の荷重が掛かる左右方向の中央に位置するものほど、漸次長さの大きいものとし、弾性変形によるクッション作用の均衡をとってある。
【００２１】
切込みスリット（１１）の代わりに、断面Ｖ状の多数の溝を設けて、その間を可撓性舌片としてもよい。さらに、可撓性舌片（１２）の可撓性を所望のものとするために、その適所に、側方向その他の方向を向く肉薄部や波曲を付しておいてもよい。
【００２２】
クッション材支持部（１０）上には、ポリウレタンなどからなる左右方向を向く肉厚のクッション材（８）が固着され、このクッション材（８）の上面（８ａ）を座枠（１）の外周部（２）における上面（２ａ）よりも上方に突出させることによって、着座者の太ももの後側に外周部（２）の上面（２ａ）などが強く当り、圧迫感を与えることのないようにしてある。
【００２３】
ネット部材（３）の周縁部（３ａ）は、座枠（１）の外周部（２）における下面（２ｃ）と、締付枠（４）の上面との間に、次のようにして挾支保持されている。
【００２４】
図５に示すように、座枠（１）の外周部（２）は、剛質の肉厚部となっており、この外周部（２）の下面（２ｃ）には、内側から、ねじ孔（７）、係止用環状溝（１６）および締付用環状溝（１７）が設けられている。
【００２５】
他方、締付枠（４）の上面には、内側から、通孔（５）、上向きの食い込み突条（１８）、および座枠（１）における外周部（２）の外側面（２ｂ）に重合しうる上向きの保護フランジ（１９）が設けられている。
【００２６】
一方、ネット部材（３）の周縁部（３ａ）には、可撓性の縁材（２０）が取付けられており、この縁材（２０）を座枠（１）の係止用環状溝（１６）内に押し込み、次いで締付枠（４）を、この締付枠（４）における食い込み突条（１８）が、座枠（１）の締付用環状溝（１７）内に食い込むようにして座枠（１）と締付枠（４）とを嵌合させ、下方からボルト（２１）を通孔（５）を挿通させて、ねじ孔（７）に締付ける。そうすると、ネット部材（３）の周縁部（３ａ）は、前記食い込み突条（１８）によって係止用環状溝（１６）内に押し込まれるとともに、前記保護フランジ（１９）と、座枠（１）における外周部（２）の外側面（２ｂ）との両者によっても強く挾持され、ネット部材（３）の周縁部（３ａ）が、十分な張力をもって均一に止着され、座枠（１）の上面に強固に張設される。
【００２７】
さらに引き続いて、縁材（９）を、図５において矢印Ｔで示すように、ネット部材（３）と座枠（１）間における内方から、座枠（１）における外周部（２）の外側面（２ｂ）と当接する位置まで押し込むことにより、ネット部材（３）を一層強固に張設することができる。
【００２８】
【発明の効果】
本発明によると、次の効果が奏せられる。
（１）請求項１記載の発明によれば、肉厚のクッション材の上面を、外周部の上面より上方に突出させてクッション材支持部に固着してあるため、着座者が背凭れを後方に傾斜させた場合、あるいは前屈みの姿勢をとった場合などにおいても、太ももの後側に圧迫感や不快感を与えず、座り心地が良好である。
【００２９】
（２）請求項２記載の発明によれば、クッション材支持部を、外周部の上面より低位置において水平方向に延設させてあるため、クッション材を大幅に肉厚にすることができ、（１）項に記載した効果が一層良好に奏せられる。
【００３０】
（３）請求項３記載の発明によれば、クッション材支持部の弾性変形とクッション材のクッション作用との両者が相俟って、（１）項に記載した効果が一段と良好に奏せられる。
【００３１】
（４）請求項４記載の発明によれば、クッション材支持部を、簡単な構造でもって、弾性変形可能とすることができる。
【００３２】
（５）請求項５記載の発明によれば、着座者の荷重が掛かり易い左右中央を、前後方向に亘って広く、かつ均一に弾性変形させることができ、（１）項に記載した効果が効率的に奏せられる。
【００３３】
（６）請求項６記載の発明によれば、切込みスリットの切込みの進行が防止され、耐久性に優れるとともに、良好な弾性変形をすることができるクッション材支持部が得られる。
【図面の簡単な説明】
【図１】本発明の一実施形態の座構造を備える椅子の側面図である。
【図２】図１に示す椅子の座構造の下方斜視図である。
【図３】図２に示す椅子の座構造の下方分解斜視図である。
【図４】図３に示す椅子の座構造における枠材とクッション材の上方分解斜視図である。
【図５】図２におけるＶ〜Ｖ線拡大縦断面図である。
【符号の説明】
（１）座枠
（２）外周部
（２ａ）上面
（２ｂ）外側面
（２ｃ）下面
（２ｄ）前部
（２ｅ）内側縁
（３）ネット部材
（３ａ）周縁部
（４）締付枠
（５）通孔
（６）ボルト
（７）ねじ孔
（８）クッション材
（９）縁材
（１０）クッション材支持部
（１１）切込みスリット
（１２）可撓性舌片
（１３）停止孔
（１４）落下防止片
（１５）膨出部
（１６）係止用環状溝
（１７）締付用環状溝
（１８）食い込み突条
（１９）保護フランジ
（２０）縁材
（２１）ボルト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seat structure of a chair in which a net member is stretched on a seat frame.
[0002]
[Prior art]
An elastically deformable net member or a porous sheet member (hereinafter referred to as a “net member” including the porous sheet member) made of a high-tensile plastic material or the like is formed on the seat frame. The seat structure of the attached chair is known.
The seat frame is generally rigid and usually has a substantially square cross section, and the upper surface supporting the peripheral edge of the net member is generally flat.
The peripheral edge of the net member is abutted and polymerized over the entire upper surface of the seat frame. When a load is applied to the net member, the net member bends and strongly hits the upper surface of the seat frame and its inner peripheral corner. Touch.
Therefore, the rigid upper surface and its inner peripheral corner strongly hit the back side of the thigh of the seated person, giving an uncomfortable feeling as well as a feeling of pressure.
In particular, when the periphery of the net member is not evenly fixed with sufficient tension, the flexure of the net member is large, and the pressure and discomfort of the seated person increase.
[0003]
In response to this, the applicant of the present application provides an overhanging piece that elastically deforms on the rear side of the upper surface with which the rear side of the seated person's thigh abuts, and attaches a tightening frame to the lower side of the seat frame, The invention has been made to reduce the feeling of pressure by applying a large tension to the net member with the tightening frame (Patent Documents 1, 2, and 3).
On the other hand, a chair in which a cushion material is embedded in a part of the upper surface of the seat frame has also been proposed (Patent Document 4).
[0004]
[Patent Document 1]
Japanese Patent Application No. 2002-213450 (refer to claim 1)
[Patent Document 2]
Japanese Patent Application No. 2002-213451 (see FIGS. 4 and 5)
[Patent Document 3]
Japanese Patent Application No. 2002-281552 (refer to claim 1, FIG. 7)
[Patent Document 4]
Special table hei 8-507935 (see FIG. 33)
[0005]
[Problems to be solved by the invention]
Although the thing described in the said patent document 4 uses the cushioning material, although the said feeling of pressure etc. is eased to some extent, since a seat frame is essentially scarce in elastic deformation, it is still fully satisfied. It is not possible.
The present invention relates to an improvement of the invention proposed by the applicant of the present invention in the above-mentioned Patent Documents 1, 2, and 3. When the seated person inclines the backrest backward or takes a forward bending posture, etc. The purpose of the present invention is also to provide a seat structure for a chair that is as comfortable as possible without giving a feeling of pressure or discomfort to the back of the thigh as much as possible.
[0006]
[Means for Solving the Problems]
According to the present invention, the above problem is solved as follows.
(1) In a seat structure of a chair in which a net member is stretched on the upper surface of a seat frame, the seat frame is horizontally oriented from the frame-shaped rigid outer periphery and the inner edge of the outer periphery of the front portion inward. A thick cushioning material facing in the left-right direction is fixed on the cushioning material support part, and the upper surface of the cushioning material is projected above the upper surface of the outer peripheral part. And it is set as the seat structure of the chair which extended | stretched the net member on the upper surface of both the cushion material and the outer peripheral part.
[0007]
(2) In said (1) term, the said cushion material support part is extended in a horizontal direction in a position lower than the upper surface of an outer peripheral part.
[0008]
(3) In the above item (1) or (2), the cushion material support portion is thin and elastically deformable in the vertical direction.
[0009]
(4) In the above item (3), the cushion material support portion is provided with a plurality of cut slits facing forward from the rear edge, and a flexible tongue piece that can be inclined elastically between adjacent cut slits. Form.
[0010]
(5) In the above item (4), among the plurality of flexible tongue pieces, the one located at the center in the left-right direction is assumed to have a gradually longer length than the other flexible tongue pieces.
[0011]
(6) In the above item (4) or (5), a stop hole for preventing the incision from progressing is provided at the back end of the incision slit.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Drawing 1 is a side view of a chair (A) provided with the seat structure of one embodiment of the present invention.
2 is a lower perspective view of the seat (B) in FIG. 1, and FIG. 3 is an exploded perspective view of the same.
[0013]
The seat (B) has a peripheral portion (3a) of a net member (3) such as high-tensile plastic on the upper surface (2a) of the outer peripheral portion (2) of a rectangular frame-shaped seat frame (1) having a closed structure. After the polymerization, the peripheral edge portion (3a) is bent downward to be superposed on the upper surface (2a) and the outer surface (2b) of the outer peripheral portion (2) of the seat frame (1), and further the lower surface of the outer peripheral portion (2). Folding inward along (2c), and tightening and tightening the fastening frame (4) forming a rectangular frame shape of a closed structure almost the same as the seat frame (1) on the lower surface of the inwardly bent portion Bolts (6) inserted from below the through holes (5) drilled at various locations on the frame (4) are screwed into the screw holes (7) drilled at corresponding locations on the lower surface (2c) of the seat frame (1). By joining together, the inwardly turned portion of the net member (3) is fixed to the lower surface (2c) of the seat frame (1).
[0014]
A cushion member (8) is provided on the upper surface of the front portion (2d) of the seat frame (1) and, as will be described later, in order to give the net member (3) sufficient tension, the net member (3) The rim material (9) is press-fitted between the peripheral edge (3a) of the frame and the outer surface (2b) of the seat frame (1).
[0015]
4 is an exploded top perspective view of the frame member (1) and the cushion member (8), and FIG. 5 is an enlarged vertical sectional view taken along the line V-V in FIG.
[0016]
The seat frame (1) in the present invention is formed of a hard plastic or an appropriate metal and has a rectangular frame-shaped outer peripheral portion (2) formed of a thick and rigid outer peripheral portion (2). ) Toward the inside from the inner edge (2e) of the outer peripheral portion (2) at a position lower than the upper surface (2a) and a thin cushion material support portion (10) extending in the horizontal direction.
[0017]
The cushion material support portion (10) is provided with a plurality of slits (11) facing forward from the rear edge, and can be elastically inclined between adjacent slits (11) (11). A flexible tongue (12) is formed.
[0018]
In order to obtain the desired flexibility of the flexible tongue piece (12), its thickness may be gradually reduced toward the distal end. A circular stop hole (13) having a diameter larger than its width is provided at the back end of the slit (11) in order to prevent the progress of the slit.
[0019]
As shown in FIG. 5, the tip of each flexible tongue (12) is bent upward to form a fall prevention piece (14) to prevent the cushion material (8) from moving and dropping. In addition, a bulging portion (15) is attached to the tip for reinforcement.
[0020]
The flexible tongue piece (12) has a progressively longer length as it is located at the center in the left-right direction where the load of the seated person is applied, and balances the cushioning action by elastic deformation.
[0021]
Instead of the incision slit (11), a plurality of grooves having a V-shaped cross section may be provided, and a space between them may be used as a flexible tongue. Furthermore, in order to make the flexibility of the flexible tongue piece (12) desired, a thin portion or a wave that faces the other direction may be attached at an appropriate position.
[0022]
On the cushion material support portion (10), a thick cushion material (8) made of polyurethane or the like facing in the left-right direction is fixed, and the upper surface (8a) of the cushion material (8) is attached to the outer periphery of the seat frame (1). By projecting upward from the upper surface (2a) of the part (2), the upper surface (2a) of the outer peripheral part (2) strongly hits the rear side of the occupant so as not to give a feeling of pressure. It is.
[0023]
The peripheral edge (3a) of the net member (3) is formed between the lower surface (2c) of the outer periphery (2) of the seat frame (1) and the upper surface of the fastening frame (4) as follows. It is held.
[0024]
As shown in FIG. 5, the outer peripheral part (2) of the seat frame (1) is a rigid thick part, and the lower surface (2c) of the outer peripheral part (2) (7) A locking annular groove (16) and a tightening annular groove (17) are provided.
[0025]
On the other hand, on the upper surface of the tightening frame (4), from the inside to the through hole (5), the upward biting ridge (18), and the outer surface (2b) of the outer peripheral portion (2) of the seat frame (1). An upward protective flange (19) which can be polymerized is provided.
[0026]
On the other hand, a flexible edge member (20) is attached to the peripheral edge (3a) of the net member (3), and this edge member (20) is attached to the annular groove (1) for locking the seat frame (1). 16) Push into the clamping frame (4), and the biting ridges (18) in the clamping frame (4) so that it bites into the clamping annular groove (17) of the seat frame (1). The seat frame (1) and the tightening frame (4) are fitted together, the bolt (21) is inserted through the hole (5) from below, and the screw hole (7) is tightened. Then, the peripheral edge (3a) of the net member (3) is pushed into the locking annular groove (16) by the biting ridge (18), and the protective flange (19) and the seat frame (1). Is firmly held by both the outer surface (2b) of the outer peripheral portion (2) and the peripheral portion (3a) of the net member (3) is uniformly fixed with sufficient tension, so that the seat frame (1) Firmly stretched on top.
[0027]
Subsequently, as shown by an arrow T in FIG. 5, the edge member (9) is moved from the inner side between the net member (3) and the seat frame (1) to the outer peripheral portion (2) of the seat frame (1). The net member (3) can be more firmly stretched by pushing it to a position where it abuts against the outer side surface (2b).
[0028]
【The invention's effect】
According to the present invention, the following effects can be obtained.
(1) According to the first aspect of the present invention, the upper surface of the thick cushion material protrudes upward from the upper surface of the outer peripheral portion and is fixed to the cushion material support portion. Even when it is tilted to the right or when it is in a forward-bent posture, it does not give a feeling of pressure or discomfort to the rear side of the thigh, and the sitting comfort is good.
[0029]
(2) According to the invention described in claim 2, since the cushion material support portion is extended in the horizontal direction at a position lower than the upper surface of the outer peripheral portion, the cushion material can be made significantly thicker. The effect described in the item (1) is further improved.
[0030]
(3) According to the invention described in claim 3, both the elastic deformation of the cushion material support portion and the cushion action of the cushion material are combined, and the effect described in the item (1) is further improved. .
[0031]
(4) According to the invention of claim 4, the cushion material support portion can be elastically deformed with a simple structure.
[0032]
(5) According to the invention described in claim 5, the left and right center where the load on the seated person is easily applied can be elastically deformed widely and uniformly in the front-rear direction, and the effect described in item (1) can be obtained. Played efficiently.
[0033]
(6) According to the invention described in claim 6, it is possible to obtain a cushion material support portion that is capable of preventing the incision of the incision slit from being progressed, having excellent durability, and capable of performing good elastic deformation.
[Brief description of the drawings]
FIG. 1 is a side view of a chair provided with a seat structure according to an embodiment of the present invention.
2 is a lower perspective view of the seat structure of the chair shown in FIG. 1. FIG.
FIG. 3 is a lower exploded perspective view of the seat structure of the chair shown in FIG.
4 is an upper exploded perspective view of a frame member and a cushion member in the seat structure of the chair shown in FIG. 3. FIG.
FIG. 5 is an enlarged vertical sectional view taken along line V-V in FIG. 2;
[Explanation of symbols]
(1) Seat frame (2) Outer peripheral part (2a) Upper surface (2b) Outer surface (2c) Lower surface (2d) Front part (2e) Inner edge (3) Net member (3a) Peripheral part (4) Fastening frame ( 5) Through hole (6) Bolt (7) Screw hole (8) Cushion material (9) Edge material (10) Cushion material support part (11) Cut slit (12) Flexible tongue piece (13) Stop hole (14 ) Fall prevention piece (15) bulging portion (16) locking annular groove (17) tightening annular groove (18) biting ridge (19) protective flange (20) edge material (21) bolt

Claims

In a seat structure of a chair in which a net member is stretched on the upper surface of the seat frame, the seat frame extends horizontally from the frame-shaped rigid outer periphery and the inner edge of the outer periphery of the front to the inside. The cushion material support portion is provided, and a thick cushion material facing in the left-right direction is fixed on the cushion material support portion, and the upper surface of the cushion material protrudes above the upper surface of the outer peripheral portion. A seat structure for a chair, characterized in that a net member is stretched on the upper surfaces of both the material and the outer periphery.

The seat structure for a chair according to claim 1, wherein the cushion material support portion extends horizontally in a position lower than the upper surface of the outer peripheral portion.

The seat structure of the chair according to claim 1 or 2, wherein the cushion material support portion is thin and elastically deformable in the vertical direction.

4. The cushion material support portion is provided with a plurality of slits facing forward from the rear edge thereof, and a flexible tongue piece that can be inclined elastically downward is formed between adjacent slit slits. The seat structure of the described chair.

5. The chair according to claim 4, wherein among the plurality of flexible tongue pieces, the one located at the center in the left-right direction has a gradually longer length than the other flexible tongue pieces. Seat structure.

The seat structure for a chair according to claim 4 or 5, wherein a stop hole for preventing the incision from proceeding is provided at the back end of the incision slit.