JP6483762B2

JP6483762B2 - Chair backrest device & chair

Info

Publication number: JP6483762B2
Application number: JP2017139373A
Authority: JP
Inventors: 山田　英伸; 英伸山田
Original assignee: Chuo Malleable Iron Co Ltd
Current assignee: Chuo Malleable Iron Co Ltd
Priority date: 2017-07-18
Filing date: 2017-07-18
Publication date: 2019-03-13
Anticipated expiration: 2037-07-18
Also published as: JP2019017745A

Description

本発明は、座体の後部から上方に延設された背凭れフレームの前面側に、合成樹脂等の硬質弾性体からなる背板が支持された椅子の背凭れ装置に関する。 The present invention relates to a chair backrest device in which a back plate made of a hard elastic body such as a synthetic resin is supported on the front side of a backrest frame extending upward from a rear portion of a seat body.

弾性変形可能な板材を被取付部材に撓み変形可能に取り付けた椅子の板材取り付け構造として、下記特許文献１に記載されたものがある。この板材取り付け構造は、被取付部材と板材のいずれか一方に設けられた孔と、いずれか他方に設けられた軸部材とを備え、軸部材が孔に挿入されて、軸部材と孔との相対的な位置関係がずれることで、板材の撓み変形を許容するものであり、具体的には、板材である腰部サポート部材の四隅に、それぞれ細長い孔を形成し、ねじである軸部材を、腰部サポート部材の表側から各孔に挿入して、被取付部材であるブラケットの四隅にねじ込むこととしている。 As a board material mounting structure of a chair in which an elastically deformable board material is flexibly attached to a member to be attached, there is one described in Patent Document 1 below. This plate material mounting structure includes a hole provided in one of the mounted member and the plate material, and a shaft member provided in either one of the members, and the shaft member is inserted into the hole so that the shaft member and the hole By shifting the relative positional relationship, bending deformation of the plate material is allowed. Specifically, elongated holes are formed in the four corners of the waist support member that is a plate material, and a shaft member that is a screw is formed. It inserts into each hole from the front side of a waist | hip | lumbar part support member, and is supposed to screw in the four corners of the bracket which is a to-be-attached member.

特開２００３−２５０６５５号公報（要約書、段落００２２参照）JP 2003-250655 A (see abstract, paragraph 0022)

しかしながら、特許文献１に記載の椅子の取り付け構造では、板材の四隅において、軸部材の孔に対する移動（ずれ）方向が孔の形状に規制されるため、着座者が板材に凭れたときの力の掛かり具合によっては、軸部材が孔に対して円滑に移動することができず、板材が撓むことが困難となって、着座者が快適な座り心地を得られないという問題があった。また、板材の四隅の孔の位置と、被取付部材の四隅の軸部材の取付位置（例えば、ねじ孔）とが合致しなければならないため、高い寸法精度が要求され、組付作業も容易ではないという問題もあった。 However, in the chair mounting structure described in Patent Document 1, since the movement (displacement) direction of the shaft member with respect to the hole is regulated by the shape of the hole at the four corners of the plate material, the force when the seated person falls into the plate material is reduced. Depending on the degree of engagement, the shaft member cannot move smoothly with respect to the hole, and it becomes difficult for the plate material to bend, and there is a problem that the seated person cannot obtain a comfortable sitting comfort. In addition, since the positions of the holes at the four corners of the plate and the mounting positions (for example, screw holes) of the shaft members at the four corners of the mounted member must match, high dimensional accuracy is required, and assembly work is easy. There was also a problem of not.

本発明は、上述した問題を解決するものであり、背板が撓むことを容易として、着座者が快適な座り心地を得られるとともに、寸法精度の要求を緩和でき、組付作業が容易となる椅子の背凭れ装置及び椅子を提供することを目的とする。 The present invention solves the above-described problem, and makes it easy for the back plate to bend, so that the occupant can obtain a comfortable seating comfort, can relax the requirements for dimensional accuracy, and can be easily assembled. An object of the present invention is to provide a chair backrest device and a chair.

代表的な図符号を括弧内に併記して述べると、本発明の椅子（Ｃ）の背凭れ装置（２）は、座体（１）の後部から上方に延設される背フレーム（３）と、背フレーム（３）の前面側に取り付けられ、合成樹脂等の硬質弾性体からなる背板（５）とを備え、背板（５）の左右の側部（５１、５２）にそれぞれ係合部（６１）が設けられ、背フレーム（３）の左右の側部（３１、３２）にそれぞれ被係合部（４１）が設けられて、各係合部（６１）は対応する被係合部（４１）に係合され、背板（５）の左右の側部（５１、５２）の係合部（６１）よりも下方部位にそれぞれ当接部（６２）が設けられ、背フレーム（３）の左右の側部（３１、３２）の被係合部（４１）よりも下方部位にそれぞれ被当接部（４２）が設けられて、各当接部（６２）は、対応する被当接部（４２）に軸着されることなく、少なくとも背板（５）の左右方向における中央部（５９）に前方から荷重が掛かったときに、対応する被当接部（４２）が備える被当接面（４２４）に前方から当接し、各係合部（６１）が、相互の距離を縮めるように、対応する被係合部（４１）に対して相対的にずれるとともに、各当接部（６２）が、相互の距離を縮めるように、被当接面（４２４）に対する当接位置をずらして、対応する被当接部（４２）に対して相対的にずれることにより、中央部（５９）に前方から荷重が掛かったときの背板（５）の撓みを許容するように構成されている。 When a representative figure code is described in parentheses, the backrest device (2) of the chair (C) of the present invention is a back frame (3) extending upward from the rear portion of the seat (1). And a back plate (5) which is attached to the front side of the back frame (3) and is made of a hard elastic body such as a synthetic resin, and is respectively associated with the left and right side portions (51, 52) of the back plate (5). A mating portion (61) is provided, and engaged portions (41) are respectively provided on the left and right side portions (31, 32) of the back frame (3), and each engaging portion (61) is a corresponding engaged portion. Abutting portions (62) are provided at lower portions than the engaging portions (61) of the left and right side portions (51, 52) of the back plate (5), and are engaged with the joint portion (41). The abutted portions (42) are respectively provided below the engaged portions (41) of the left and right side portions (31, 32) of (3), and each abutting portion (62 Without being pivotally mounted to the corresponding abutted portion (42), when a load is applied from the front to the central portion (59) in the lateral direction of at least the back plate (5), corresponding abutted portion The abutment surface (424) included in (42) abuts against the abutted surface (424) from the front , and each engagement portion (61) is relatively relative to the corresponding engagement portion (41) so as to reduce the mutual distance. The position of contact with respect to the abutted surface (424) is shifted so that the abutting portions (62) reduce the mutual distance and shift relative to the corresponding abutted portion (42). By shifting, the back plate (5) is allowed to bend when a load is applied to the central portion (59) from the front.

このように、本発明の椅子の背凭れ装置は、着座者が凭れることにより、背板の左右方向における中央部に前方から荷重が掛かったときに、各係合部が、相互の距離を縮めるように、対応する被係合部に対して相対的にずれるとともに、各当接部が、相互の距離を縮めるように、被当接面に対する当接位置をずらして、対応する被当接部に対して相対的にずれる。すなわち、当接部は部分的に被当接面に接触しているだけであるので、当接部と被当接面との間の摩擦は小さい。また、当接部は被当接面に当接しているだけであるので、当接部の被当接面に対するずれ方向は比較的自由である。このため、容易に当接部がずれて、背板が撓むことが容易となり、着座者が快適な座り心地を得られる。また、各当接部はある程度の広さを持った被当接面に当接されればよいため、各当接部及び各被当接部については、高い寸法精度が要求されず、組付作業も容易である。このため、全体として、背凭れ装置に対する寸法精度の要求が緩和され、組付作業も容易となる。 As described above, the chair backrest device according to the present invention is configured so that when a seat occupant falls, when a load is applied from the front to the center portion in the left-right direction of the back plate, The contacted portions are shifted relative to the corresponding engaged portions so as to be contracted, and the contact positions of the contacted portions with respect to the contacted surfaces are shifted so as to reduce the mutual distance. It shifts relative to the part. That is, since the contact portion is only partially in contact with the contacted surface, the friction between the contact portion and the contacted surface is small. Further, since the abutting portion is only in contact with the abutted surface, the displacement direction of the abutting portion with respect to the abutted surface is relatively free. For this reason, it becomes easy for the contact portion to easily shift and the back plate to bend, and the seated person can obtain a comfortable sitting comfort. In addition, since each abutting portion only needs to abut on a contacted surface having a certain size, each abutting portion and each abutting portion do not require high dimensional accuracy, and are assembled. Work is also easy. For this reason, as a whole, the requirement of dimensional accuracy for the backrest device is eased, and the assembly work is facilitated.

ここで、前記各被当接部（４２）が、前記背フレーム（３）の前面から前方に突出する上保護壁部（４２１）と、前記上保護壁部（４２１）の下方に配置され前記背フレーム（３）の前面から前方に突出する下保護壁部（４２２）とを備え、前記各被当接部（４２）が備える前記被当接面（４２４）は、当該被当接部（４２）の前記上保護壁部（４２１）と前記下保護壁部（４２２）との間であって、前記上保護壁部（４２１）の前端部及び前記下保護壁部（４２２）の前端部よりも後方位置に、前方を向いて配置されていることとしてもよい。
これによれば、当接部と被当接面との間に指等を挟むことを防止できる。
また、前記背板（５）が、前記左右の側部（５１、５２）の間に、前後に貫通する多数の貫通孔（５６）が形成された背凭れ主部（５５）を備え、前記背凭れ主部（５５）が、着座者の腰が当たる部分に、左右方向に延びて前記背板（５）の前記左右の側部（５１、５２）同士を連結する１以上の高剛性部（５７、５８）を備え、前記高剛性部（５７、５８）は、前記貫通孔（５６）を有さないもの又は単位面積当たりの前記貫通孔（５６）の総開口面積が相対的に小さいものとされることにより、前記背凭れ主部（５５）における他の部分よりも剛性が高くされ、前記各当接部（６２）は、前記背板（５）の前記左右の側部（５１、５２）における前記高剛性部（５７）との連結部付近に設けられていることとしてもよい。 Here, each said contacted part (42) is arrange | positioned under the upper protective wall part (421) which protrudes ahead from the front surface of the said back frame (3), and the said upper protective wall part (421). A lower protective wall portion (422) protruding forward from the front surface of the back frame (3), and the abutted surface (424) of each of the abutted portions (42) 42) between the upper protective wall portion (421) and the lower protective wall portion (422), the front end portion of the upper protective wall portion (421) and the front end portion of the lower protective wall portion (422). It is good also as arrange | positioning in the back position rather than the front.
According to this, it is possible to prevent a finger or the like from being sandwiched between the contact portion and the contacted surface.
The back plate (5) includes a backrest main portion (55) in which a plurality of through holes (56) penetrating in the front-rear direction are formed between the left and right side portions (51, 52), One or more high-rigidity parts in which the backrest main part (55) extends in the left-right direction to the part where the seated person's waist hits and connects the left and right side parts (51, 52) of the back plate (5) (57, 58), the high rigidity portion (57, 58) does not have the through hole (56) or the total opening area of the through hole (56) per unit area is relatively small As a result, the rigidity of the backrest main portion (55) is made higher than that of the other portions, and the contact portions (62) are formed on the left and right side portions (51) of the back plate (5). , 52) may be provided in the vicinity of the connecting portion with the high-rigidity portion (57).

これによれば、背板において着座者の腰が当たる部分が相対的に高剛性とされるとともに、背板の左右の側部における高剛性部との連結部付近に当接部が設けられているため、着座者が背板に凭れたときに、高剛性部で腰を受け止めて、さらにその荷重を当接部が被当接面に当接することにより背フレームで受け止めるので、着座者の腰をしっかり支えることができる。また、上述したように、当接部は、被当接面との間の摩擦が小さく、比較的自由に被当接部に対してずれることが可能であるため、背板における着座者の腰が当たる部分が高剛性であるにもかかわらず撓むことが容易となり、着座者はより快適な座り心地を得られる。 According to this, the portion where the seated person's waist hits the back plate is relatively high rigidity, and the contact portion is provided in the vicinity of the connecting portion with the high rigidity portion on the left and right sides of the back plate. Therefore, when the occupant falls on the back plate, the waist is received by the high-rigidity part, and the load is received by the back frame when the contact part abuts against the contacted surface. Can be firmly supported. Further, as described above, the contact portion has a small friction with the contacted surface and can be relatively freely displaced from the contacted portion. It is easy to bend despite the high rigidity of the portion that hits, and the seated person can obtain a more comfortable sitting comfort.

本発明の椅子は、本発明の背凭れ装置を備えるため、背板が撓むことが容易であり、着座者が快適な座り心地を得られる。 Since the chair of the present invention includes the backrest device of the present invention, it is easy for the back plate to bend, and the seated person can obtain a comfortable sitting comfort.

本発明によれば、背板が撓むことを容易として、着座者が快適な座り心地を得られる椅子の背凭れ装置及び椅子を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the backrest apparatus and chair of a chair which make it easy for a backplate to bend and a seated person can obtain comfortable seating comfort can be provided.

実施形態に係る椅子の斜視図である。It is a perspective view of the chair concerning an embodiment. 実施形態に係る背凭れ装置の斜視図である。It is a perspective view of the backrest device concerning an embodiment. 実施形態に係る背凭れ装置の側面図である。It is a side view of the backrest device concerning an embodiment. 実施形態に係る背フレーム及び係合ピンの斜視図である。It is a perspective view of the back frame and engagement pin concerning an embodiment. 実施形態に係る背板の斜視図である。It is a perspective view of the back board concerning an embodiment. 実施形態に係る背板の正面図である。It is a front view of the back board concerning an embodiment. 図６のＡ−Ｂ間の拡大図であり、前後方向に貫通していない部分を薄墨で示したものである。It is an enlarged view between AB of FIG. 6, and the part which has not penetrated in the front-back direction is shown with the light ink. 図３のVIII-VIII線要部断面拡大図であり、（ａ）は背板の左右方向における中央部に荷重が掛かっていない状態、（ｂ）は同中央部に前方から荷重が掛かった状態を示す。It is the VIII-VIII line principal part enlarged view of the VIII-VIII line of FIG. 3, (a) is the state where the load is not applied to the center part in the left-right direction of a backplate, (b) is the state where the load was applied to the center part from the front. Indicates. 図３のIX-IX線要部断面拡大図であり、（ａ）は背板の左右方向における中央部に荷重が掛かっていない状態、（ｂ）は同中央部に前方から荷重が掛かった状態を示す。FIG. 4 is an enlarged cross-sectional view of a principal part of the IX-IX line in FIG. 3, (a) is a state where no load is applied to the center part in the left-right direction of the back plate, and (b) is a state where a load is applied to the center part from the front. Indicates.

以下、本発明の一実施形態の椅子Ｃについて図面に基づいて説明する。なお、本明細書における左右及び前後は、椅子Ｃに着座した着座者にとっての左右及び前後をいうものとする。また、左右に設けられた構成要素であって同じ符号を用いた構成要素については、適宜、左に設けられた構成要素の符号にＬ、右に設けられた構成要素の符号にＲを付けて表記することとする。 Hereinafter, a chair C according to an embodiment of the present invention will be described with reference to the drawings. In the present specification, left and right and front and rear refer to left and right and front and rear for a seated person sitting on the chair C. For components provided on the left and right and using the same reference numerals, L is added to the reference numerals of the constituent elements provided on the left, and R is added to the reference numerals of the constituent elements provided on the right. I will write it.

図１に示すように、椅子Ｃは、着座者が着座する座体１と、座体１の後部に取り付けられた背凭れ装置２と、座体１の下部に軸部材８を介して取り付けられた脚体９とから構成されている。背凭れ装置２は、座体１の後部から上方に延設された背フレーム３と、背フレーム３の前面側に取り付けられた背板５とから構成されている。 As shown in FIG. 1, the chair C is attached to a seat body 1 on which a seated person sits, a backrest device 2 attached to the rear part of the seat body 1, and a lower portion of the seat body 1 via a shaft member 8. And a leg body 9. The backrest device 2 includes a back frame 3 extending upward from the rear portion of the seat body 1 and a back plate 5 attached to the front side of the back frame 3.

背凭れ装置２は、図２〜５に示すように、背板５の下部５４に設けられた左右の係止部６３、６３が、背フレーム３の下部３４に設けられた左右の被係止部４３、４３にそれぞれ係止され、背板５の左右の側部５１、５２に設けられた左右の係合部６１、６１が、背フレーム３の左右の側部３１、３２に設けられた左右の被係合部４１、４１に、それぞれ係合される（具体的には、取付部材である係合ピン７で取り付けられる）ことにより、背板５が背フレーム３に取り付けられている。そして、このように背板５が背フレーム３に取り付けられた状態で、背板５の左右の側部５１、５２に設けられた左右の当接部６２、６２は、背フレーム３の左右の側部３１、３２に設けられた左右の被当接部４２、４２が備える被当接面４２４、４２４にそれぞれ当接している。係合部６１Ｌと係合部６１Ｒ、当接部６２Ｌと当接部６２Ｒ、係止部６３Ｌと係止部６３Ｒは、それぞれ、背板５において左右対称な位置に配置され、これに対応して、被係合部４１Ｌと被係合部４１Ｒ、被当接部４２Ｌと被当接部４２Ｒ、被係止部４３Ｌと被係止部４３Ｒとは、それぞれ、背フレーム３において左右対称な位置に配置されている。 2 to 5, the backrest device 2 includes left and right locking portions 63, 63 provided on the lower portion 54 of the back plate 5, and left and right locked portions provided on the lower portion 34 of the back frame 3. The left and right engaging portions 61 and 61 provided on the left and right side portions 51 and 52 of the back plate 5 are provided on the left and right side portions 31 and 32 of the back frame 3, respectively. The back plate 5 is attached to the back frame 3 by being engaged with the left and right engaged portions 41, 41 (specifically, attached by the engaging pins 7 that are attachment members). In the state where the back plate 5 is attached to the back frame 3 in this way, the left and right contact portions 62 and 62 provided on the left and right side portions 51 and 52 of the back plate 5 are The left and right contacted portions 42 and 42 provided on the side portions 31 and 32 are in contact with the contacted surfaces 424 and 424, respectively. The engaging portion 61L and the engaging portion 61R, the abutting portion 62L and the abutting portion 62R, and the locking portion 63L and the locking portion 63R are arranged at symmetrical positions on the back plate 5, respectively. The engaged part 41L and the engaged part 41R, the abutted part 42L and the abutted part 42R, and the engaged part 43L and the engaged part 43R are respectively in symmetrical positions on the back frame 3. Has been placed.

背フレーム３について詳説すると、背フレーム３は、硬質の合成樹脂からなり、図２〜４に示すように、後方に膨出するように湾曲しつつ略Ｙ字形状をなす下部３４と、下部３４の左右の上端部から上方に延設された長尺板状の左右の側部３１、３２と、左右の側部３１、３２の上端部同士を連結し、後方に膨出するように湾曲する横杆状の上部３３とを備えている。 The back frame 3 will be described in detail. The back frame 3 is made of a hard synthetic resin, and as shown in FIGS. The long plate-like left and right side portions 31 and 32 extending upward from the left and right upper end portions are connected to the upper end portions of the left and right side portions 31 and 32 and curved so as to bulge backward. And a recumbent upper portion 33.

背フレーム３の下部３４は、幅広に形成されて上下方向に立設された中央支持部３５と、中央支持部３５の上端部から左右斜め上方に延設された左右の延設部３６、３６と、中央支持部３５の下端部から前方に延出する取付基部３７とから構成され、図１に示すように、取付基部３７が、座体１の下部の後面側に取り付けられたロッキング装置１０に螺子で取り付けられることにより、背フレーム３は座体１に取り付けられている。 A lower portion 34 of the back frame 3 is formed with a wide central support portion 35 that is formed upright and vertically and left and right extension portions 36 and 36 that extend obliquely upward and downward from the upper end portion of the central support portion 35. And a mounting base 37 extending forward from the lower end of the central support 35, and the mounting base 37 is attached to the rear surface of the lower portion of the seat body 1 as shown in FIG. The back frame 3 is attached to the seat body 1 by being attached with screws.

背フレーム３の各被係合部４１は、背フレーム３の左右の側部３１、３２の上部の前面側に、それぞれ前方に突出するように設けられている。各被係合部４１は、上下に並設された上下方向を軸方向とする略円環状の２つの軸受部４１１、４１２から構成されている。軸受部４１１、４１２の内側の孔は略真円形状とされ、上の軸受部４１１と下の軸受部４１２との間隔は、背板５の係合部６１の上下方向の長さよりも若干長くされている。 Each engaged portion 41 of the back frame 3 is provided on the front side of the upper part of the left and right side portions 31 and 32 of the back frame 3 so as to protrude forward. Each engaged portion 41 is composed of two substantially annular bearing portions 411 and 412 that are arranged side by side in the vertical direction with the vertical direction as the axial direction. The inner holes of the bearing portions 411 and 412 are substantially circular, and the distance between the upper bearing portion 411 and the lower bearing portion 412 is slightly longer than the vertical length of the engaging portion 61 of the back plate 5. Has been.

背フレーム３の各被当接部４２は、背フレーム３の左右の側部３１、３２の前面側において、被係合部４１よりも下方部位に、それぞれ前方に突出するように設けられている。被当接部４２Ｌと被当接部４２Ｒとは、左右対称な形状とされ、各被当接部４２は、背フレーム３の前面から前方に突出する略水平板状の上保護壁部４２１と、上保護壁部４２１の下方に配置され、背フレーム３の前面から前方に突出する略水平板状の下保護壁部４２２と、上保護壁部４２１と下保護壁部４２２との間に配置され、突出長さを上保護壁部４２１及び下保護壁部４２２よりは小として、背フレーム３の前面から前方に突出する被当接面構成部４２３とから構成されている。被当接面構成部４２３の前面は、後述する当接部６２の湾曲壁部６２１が当接する被当接面４２４に相当する（図９参照）。上保護壁部４２１及び下保護壁部４２２は、被当接面構成部４２３と湾曲壁部６２１との間に指等を挟むことを防止するためのものである。 Each contacted portion 42 of the back frame 3 is provided on the front side of the left and right side portions 31 and 32 of the back frame 3 so as to protrude forward from the engaged portion 41. . The abutted portion 42L and the abutted portion 42R are symmetric in shape, and each abutted portion 42 includes a substantially horizontal plate-like upper protective wall portion 421 protruding forward from the front surface of the back frame 3. The lower protective wall 422 is disposed below the upper protective wall 421 and protrudes forward from the front surface of the back frame 3. The lower protective wall 422 is disposed between the upper protective wall 421 and the lower protective wall 422. The protrusion length is smaller than that of the upper protective wall portion 421 and the lower protective wall portion 422, and the contact surface forming portion 423 protrudes forward from the front surface of the back frame 3. The front surface of the abutted surface constituting portion 423 corresponds to the abutted surface 424 on which a curved wall portion 621 of the abutting portion 62 described later abuts (see FIG. 9). The upper protective wall portion 421 and the lower protective wall portion 422 are for preventing a finger or the like from being sandwiched between the contacted surface constituting portion 423 and the curved wall portion 621.

被当接面４２４は略前方を向く面であり、略平面状であるが、厳密には、当接部６２との当接部位の面積（接触面積）をより小さくして当接部６２がスライドし易いように、水平方向の断面が非常に緩やかに湾曲して前方に極僅かに膨出する曲面とされている。なお、被当接面４２４を、全くの平面状としてもよい。また、被当接面構成部４２３は、被当接面４２４に開口する肉抜き部分を有しており、これによっても、当接部６２と被当接面４２４との接触面積は小さくされている。 The contacted surface 424 is a surface that faces substantially forward and has a substantially planar shape. Strictly speaking, the area (contact area) of the contact portion with the contact portion 62 is made smaller so that the contact portion 62 is In order to facilitate sliding, the horizontal cross section is a curved surface that curves very gently and bulges slightly forward. Note that the abutted surface 424 may be completely flat. In addition, the abutted surface constituting portion 423 has a thinned portion that opens to the abutted surface 424, and this also reduces the contact area between the abutting portion 62 and the abutted surface 424. Yes.

背フレーム３の各被係止部４３は、中央支持部３５の左右の側部に、それぞれ前面側に前方に突出するように設けられている。各被係止部４３は、上方に開口する孔を有している。 Each locked portion 43 of the back frame 3 is provided on the left and right side portions of the center support portion 35 so as to protrude forward on the front side. Each locked portion 43 has a hole that opens upward.

背板５について詳説すると、背板５は、硬質弾性体である合成樹脂製であり、図６に示すように、正面視において六角形状に近い略矩形状をなすとともに、図３に示すように、上下方向における中央部よりも下寄りの部分で、前方に膨出するように略へ字形状に屈曲している。 The back plate 5 will be described in detail. The back plate 5 is made of a synthetic resin, which is a hard elastic body, and has a substantially rectangular shape close to a hexagonal shape when viewed from the front, as shown in FIG. 6, and as shown in FIG. It is bent in a substantially square shape so as to bulge forward at a portion lower than the central portion in the vertical direction.

背板５は、図５、６に示すように、左右の側部５１、５２の間に設けられた背凭れ主部５５に、前後に貫通する多数の貫通孔５６を有している。詳しくは、背板５は、板状の左右の側部５１、５２と、左右の側部５１、５２の下端部同士を連結する板状の下部５４と、左右の側部５１、５２の上端部同士を連結する板状の上部５３とで構成される外枠部５０を備え、背凭れ主部５５は外枠部５０で囲まれた内側部分である。なお、外枠部５０の板厚は、背凭れ主部５５の板厚よりも、若干厚くされている。各貫通孔５６は、左右方向の幅よりも上下方向の長さが長い長孔とされ、外枠部５０に接することにより長さが制限されているものを除き、上下方向の長さは全ての貫通孔５６で同一とされている。 As shown in FIGS. 5 and 6, the back plate 5 has a large number of through holes 56 penetrating back and forth in a backrest main portion 55 provided between the left and right side portions 51 and 52. Specifically, the back plate 5 includes plate-like left and right side portions 51 and 52, a plate-like lower portion 54 that connects lower end portions of the left and right side portions 51 and 52, and upper ends of the left and right side portions 51 and 52. The outer frame part 50 comprised by the plate-shaped upper part 53 which connects parts is provided, and the backrest main part 55 is an inner part enclosed by the outer frame part 50. FIG. The plate thickness of the outer frame portion 50 is slightly thicker than the plate thickness of the backrest main portion 55. Each through hole 56 is a long hole whose length in the vertical direction is longer than the width in the left-right direction, and the length in the vertical direction is all except that the length is limited by contacting the outer frame portion 50. These through holes 56 are the same.

また、背凭れ主部５５は、着座者の腰が当たる部分（ここでは、上下方向における中央部よりも下寄りの部分）に、左右方向に延びて左右の側部５１、５２同士を連結する第１高剛性部５７と、第１高剛性部５７の下方に設けられ、左右方向に延びて左右の側部５１、５２同士を連結する第２高剛性部５８とを備えている。第１高剛性部５７及び第２高剛性部５８は、貫通孔５６を有さないものとされることにより、背凭れ主部５５における他の部分（ここでは、第１高剛性部５７より上方の部分、第１高剛性部５７と第２高剛性部５８の間の部分、第２高剛性部５８より下方の部分）よりも剛性が高くされている。なお、図７は、背板５の第１高剛性部５７及び第２高剛性部５８を含む部分の拡大図であり、前後方向に貫通していない部分を薄墨で示したものであるが、この図に示すように、第１高剛性部５７及び第２高剛性部５８の上下に複数配置されている凹部６０は、前後方向に貫通せず、閉塞されている。各凹部６０は、前後方向の中央部で閉塞されているため、背板５の前面と後面のいずれにおいても凹んでいる。 Further, the backrest main portion 55 extends in the left-right direction to connect the left and right side portions 51 and 52 to a portion where the seated person's waist hits (here, a portion lower than the central portion in the vertical direction). The first high-rigidity portion 57 and a second high-rigidity portion 58 that are provided below the first high-rigidity portion 57 and extend in the left-right direction and connect the left and right side portions 51 and 52 to each other. Since the first high-rigidity portion 57 and the second high-rigidity portion 58 do not have the through-holes 56, the other portions of the backrest main portion 55 (here, higher than the first high-rigidity portion 57) , The portion between the first high-rigidity portion 57 and the second high-rigidity portion 58, and the portion below the second high-rigidity portion 58). FIG. 7 is an enlarged view of a portion including the first high-rigidity portion 57 and the second high-rigidity portion 58 of the back plate 5, and a portion not penetrating in the front-rear direction is indicated by light ink. As shown in this figure, the plurality of concave portions 60 arranged above and below the first high-rigidity portion 57 and the second high-rigidity portion 58 are closed without penetrating in the front-rear direction. Since each recessed part 60 is obstruct | occluded in the center part of the front-back direction, it is recessed in both the front surface of the backplate 5, and a rear surface.

背板５は、着座者の腰に沿うように、第１高剛性部５７と第２高剛性部５８との中間部位で、上述したように略へ字形状に屈曲されている。そして、この屈曲部分の剛性をさらに高めるために、背板５の後面には、上下方向に延びる２本のリブ６４が、背板５の左右対称な位置に突設されている。また、背凭れ主部５５の弾性の調整のために、前面に上下方向に延びる凹溝６５が複数形成されるとともに、後面にも上下方向に延びる凹溝６６が複数形成され、前面の凹溝６５と後面の凹溝６６とは、前後方向で重ならないように配置されている。 As described above, the back plate 5 is bent in a substantially square shape at an intermediate portion between the first high-rigidity portion 57 and the second high-rigidity portion 58 along the waist of the seated person. In order to further increase the rigidity of the bent portion, two ribs 64 extending in the vertical direction are provided on the rear surface of the back plate 5 so as to project from the left and right symmetrical positions of the back plate 5. Further, in order to adjust the elasticity of the backrest main portion 55, a plurality of concave grooves 65 extending in the vertical direction are formed on the front surface, and a plurality of concave grooves 66 extending in the vertical direction are also formed on the rear surface. 65 and the rear groove 66 are arranged so as not to overlap in the front-rear direction.

背板５の各係合部６１は、背板５の左右の側部５１、５２の上部の後面側に、それぞれ後方に突出するように設けられている。各係合部６１は、上下方向を軸方向とする筒形状とされ、内側に形成されている係合孔６１１は、軸に直交する方向の断面が左右方向に長い長円形状とされている。 Each engaging portion 61 of the back plate 5 is provided on the rear surface side of the upper part of the left and right side portions 51 and 52 of the back plate 5 so as to protrude rearward. Each engagement portion 61 has a cylindrical shape with the vertical direction as the axial direction, and the engagement hole 611 formed inside has an elliptical shape with a cross section perpendicular to the axis extending in the left-right direction. .

背板５の各当接部６２は、背板５の左右の側部５１、５２の後面側の係合部６１よりも下方部位であって、左右の側部５１、５２と第１高剛性部５７との連結部付近に、それぞれ後方に突出するように設けられている。当接部６２Ｌと当接部６２Ｒとは、左右対称な形状とされ、各当接部６２は、図５に示すように、背板５の後面から後方に膨出するように湾曲しつつ左右に延びて設けられた湾曲壁部６２１と、湾曲壁部６２１の前面と背板５の後面とを連結して湾曲壁部６２１を補強する補強壁部６２２と、湾曲壁部６２１の背凭れ主部５５側の端部に連結されて後方に突出する略鉛直板状の保護壁部６２３と、湾曲壁部６２１の下端縁部と背板５の後面との間を閉塞する底壁部６２４とから構成されている。なお、保護壁部６２３は、湾曲壁部６２１と背フレーム３の被当接部４２との間に指等を挟むことを防止するためのものである。 Each contact portion 62 of the back plate 5 is a lower part than the engagement portions 61 on the rear surface side of the left and right side portions 51 and 52 of the back plate 5, and the first high rigidity is provided with the left and right side portions 51 and 52. It is provided in the vicinity of the connecting portion with the portion 57 so as to protrude rearward. The contact portion 62L and the contact portion 62R have a bilaterally symmetric shape, and each contact portion 62 is curved so as to bulge rearward from the rear surface of the back plate 5 as shown in FIG. A curved wall portion 621 provided to extend to the wall, a reinforcing wall portion 622 that reinforces the curved wall portion 621 by connecting the front surface of the curved wall portion 621 and the rear surface of the back plate 5, and the backrest of the curved wall portion 621. A substantially vertical plate-like protective wall portion 623 that is connected to an end portion on the side of the portion 55 and protrudes backward; a bottom wall portion 624 that closes between the lower end edge of the curved wall portion 621 and the rear surface of the back plate 5; It is composed of The protective wall portion 623 is for preventing a finger or the like from being sandwiched between the curved wall portion 621 and the contacted portion 42 of the back frame 3.

背板５の各係止部６３は、図５に示すように、背板５の下部５４の後面側に、それぞれ後方に突出するように設けられ、下向きの鉤状（略Ｌ字形状）をなしている。 As shown in FIG. 5, each locking portion 63 of the back plate 5 is provided on the rear surface side of the lower portion 54 of the back plate 5 so as to protrude rearward, and has a downward hook shape (substantially L-shaped). There is no.

背板５の背フレーム３への取付手順について説明する。まず、背板５の各係止部６３の先端部を、背フレーム３の対応する被係止部４３の孔に挿入する。なお、「対応する」とは同じ側に設けられているもの（例えば、左の係止部６３Ｌに対応する被係止部４３は、左の被係止部４３Ｌ）をいう。これにより、左右の係止部６３、６３は左右の被係止部４３、４３に係止される。このように係止部６３、６３が被係止部４３、４３に係止された状態で、背板５の各係合部６１は、背フレーム３の対応する被係合部４１の軸受部４１１、４１２間に対向することとなる。 A procedure for attaching the back plate 5 to the back frame 3 will be described. First, the distal end portion of each locking portion 63 of the back plate 5 is inserted into the hole of the corresponding locked portion 43 of the back frame 3. Note that “corresponding” refers to what is provided on the same side (for example, the locked portion 43 corresponding to the left locking portion 63L is the left locked portion 43L). As a result, the left and right locking portions 63 and 63 are locked to the left and right locked portions 43 and 43. In this state where the locking portions 63 and 63 are locked to the locked portions 43 and 43, each engaging portion 61 of the back plate 5 is a bearing portion of the corresponding engaged portion 41 of the back frame 3. 411 and 412 are opposed to each other.

次に、背板５の各係合部６１を、対応する被係合部４１の軸受部４１１、４１２間に配置し、係合ピン７を被係合部４１の上方から、軸受部４１１の内側の孔、係合部６１の係合孔６１１、軸受部４１２の内側の孔に順に挿通する。これにより、左右の係合部６１、６１が左右の被係合部４１、４１にそれぞれ係合され（具体的には、取り付けられ）、各係合部６１は、係合ピン７を抜かなければ被係合部４１から外れないようになる。なお、各係合ピン７は、軸方向に直交する断面が略真円形状をなし、その径を縮小・復帰するように弾性が付されており、先端に抜け止め用の爪部を有して、径を縮小させて軸受部４１１、４１２に挿通された後、径が弾性復帰するため、外力を加えなければ軸受部４１１、４１２から抜けない。図８の（ａ）に示すように、各係合部６１の内周面（すなわち、各係合孔６１１の周壁面）は、挿通された係合ピン７の周壁に部分的に摺接し、各係合部６１の外周面は、背フレーム３の前面から離間している。また、各係合部６１の上端面とその係合部６１が係合されている被係合部４１の軸受部４１１の下面との間、及び、各係合部６１の下端面とその係合部６１が係合されている被係合部４１の軸受部４１２の上面との間には、それぞれ若干の隙間がある。 Next, each engaging portion 61 of the back plate 5 is disposed between the bearing portions 411 and 412 of the corresponding engaged portion 41, and the engaging pin 7 is placed above the engaged portion 41 from the bearing portion 411. The inner hole, the engaging hole 611 of the engaging portion 61, and the inner hole of the bearing portion 412 are inserted in order. As a result, the left and right engaging portions 61 and 61 are engaged with the left and right engaged portions 41 and 41 (specifically, attached), and each engaging portion 61 must remove the engaging pin 7. Thus, it will not be disengaged from the engaged portion 41. Each of the engagement pins 7 has a substantially circular cross section perpendicular to the axial direction, and is elastically provided so that its diameter can be reduced and restored, and has a claw portion for preventing it from coming off. Then, after the diameter is reduced and inserted into the bearing portions 411 and 412, the diameter is elastically restored, so that the bearing portions 411 and 412 cannot be removed unless an external force is applied. As shown in FIG. 8A, the inner peripheral surface of each engaging portion 61 (that is, the peripheral wall surface of each engaging hole 611) partially slidably contacts the peripheral wall of the inserted engaging pin 7. The outer peripheral surface of each engaging portion 61 is separated from the front surface of the back frame 3. Further, between the upper end surface of each engaging portion 61 and the lower surface of the bearing portion 411 of the engaged portion 41 with which the engaging portion 61 is engaged, and the lower end surface of each engaging portion 61 and its engagement. There are slight gaps between the upper surface of the bearing portion 412 of the engaged portion 41 with which the mating portion 61 is engaged.

このように、各係止部６３が対応する被係止部４３に係止され、各係合部６１が対応する被係合部４１に係合されることにより、背板５が背フレーム３に取り付けられて、背凭れ装置２が完成し、この状態で、各当接部６２は、図２に示すように、対応する被当接部４２の上保護壁部４２１と下保護壁部４２２との間に配置され、図９の（ａ）に示すように、湾曲壁部６２１の前面の一部が、被当接面構成部４２３の前面の被当接面４２４に当接している。当接部６２とその上に配置される上保護壁部４２１との間、当接部６２とその下に配置される下保護壁部４２２との間は、それぞれ若干離間している。したがって、当接部６２は上下方向の若干の移動（ずれ）も可能であり、被当接面４２４に対して比較的自由に移動することができる。背凭れ装置２は、上述したように、取付基部３７が座体１の後部にロッキング装置１０を介して取り付けられることにより、座体１に取り付けられる。 In this way, each locking portion 63 is locked to the corresponding locked portion 43, and each engagement portion 61 is engaged with the corresponding locked portion 41, so that the back plate 5 is connected to the back frame 3. The backrest device 2 is completed, and in this state, each contact portion 62 has an upper protection wall portion 421 and a lower protection wall portion 422 corresponding to the contacted portion 42 as shown in FIG. As shown in FIG. 9A, a part of the front surface of the curved wall portion 621 is in contact with the contacted surface 424 on the front surface of the contacted surface constituting portion 423. The contact portion 62 and the upper protective wall portion 421 disposed thereon are slightly separated from each other, and the contact portion 62 and the lower protective wall portion 422 disposed below the contact portion 62 are slightly spaced from each other. Therefore, the contact portion 62 can be slightly moved (displaced) in the vertical direction, and can move relatively freely with respect to the contacted surface 424. As described above, the backrest device 2 is attached to the seat body 1 by attaching the attachment base portion 37 to the rear portion of the seat body 1 via the locking device 10.

以上のように構成された背凭れ装置２及び椅子Ｃの作用及び効果について説明する。着座者が背凭れ装置２に凭れていない状態、すなわち、背板５の左右方向における中央部５９に荷重が掛かっていない状態（以下、「無荷重状態」という。）では、図８の（ａ）に示すように、各係合部６１は、係合孔６１１の左右方向の中央位置が、係合ピン７の中心に対して外方（背板５にとっての外側）にずれている。具体的には、左の係合部６１Ｌでは左方乃至は左斜め前方に、右の係合部６１Ｒでは右方乃至は右斜め前方にずれている。また、無荷重状態では、湾曲壁部６２１の前面の一部が、被当接面４２４における図９の（ａ）に示す部位に当接している。 The operation and effect of the backrest device 2 and the chair C configured as described above will be described. In a state where the seated person is not leaning on the backrest device 2, that is, in a state where no load is applied to the central portion 59 in the left-right direction of the back plate 5 (hereinafter referred to as “no load state”), FIG. As shown in FIG. 5, in each engaging portion 61, the center position in the left-right direction of the engaging hole 611 is shifted outward (outside from the back plate 5) with respect to the center of the engaging pin 7. Specifically, the left engagement portion 61L is shifted leftward or diagonally forward left, and the right engagement portion 61R is shifted rightward or diagonally forward right. Further, in a no-load state, a part of the front surface of the curved wall portion 621 is in contact with the portion shown in FIG.

着座者が背凭れ装置２に凭れると、背板５の中央部５９に前方から荷重が掛かった状態（以下、「荷重状態」という。）となる。荷重状態では、背板５の中央部５９が後方に撓もうとするため、背板５の左右の側部５１、５２に設けられている係合部６１は、中央部５９側に引っ張られることとなるが、各係合ピン７は軸方向に直交する断面が略真円形状とされ、各係合孔６１１は軸方向に直交する断面が左右方向に長い長円とされているため、各係合部６１が、係合ピン７の周壁の一部に摺接しつつ移動し、図８の（ｂ）に示すように、無荷重状態（図８の（ａ）参照）よりも、内方（背板５にとっての内側）にずれる（スライドする）こととなる。具体的には、左の係合部６１Ｌは右方乃至は右斜め後方に、右の係合部６１Ｒは左方乃至は左斜め後方に、スライドすることとなる。このスライド方向を、図８の（ｂ）に矢印で示す。すなわち、各係合部６１が、相互の距離を縮めるように、対応する被係合部４１に対して相対的にずれることとなる。 When the seated person falls on the backrest device 2, a load is applied to the central portion 59 of the back plate 5 from the front (hereinafter referred to as “load state”). In the loaded state, the central portion 59 of the back plate 5 tends to bend backward, so that the engaging portions 61 provided on the left and right side portions 51 and 52 of the back plate 5 are pulled toward the central portion 59 side. However, each engaging pin 7 has a substantially circular cross section orthogonal to the axial direction, and each engaging hole 611 has an elliptical shape with a cross section orthogonal to the axial direction elongated in the left-right direction. The engaging portion 61 moves while being in sliding contact with a part of the peripheral wall of the engaging pin 7, and as shown in FIG. 8 (b), it is more inward than in the no-load state (see FIG. 8 (a)). It will shift (slide) to the inside (back plate 5). Specifically, the left engagement portion 61L slides to the right or diagonally rearward to the right, and the right engagement portion 61R slides to the left or diagonally backward to the left. This sliding direction is indicated by an arrow in FIG. That is, each engaging part 61 will shift | deviate relatively with respect to the corresponding to-be-engaged part 41 so that mutual distance may be shortened.

また、荷重状態では、背板５の中央部５９が後方に撓もうとするため、背板５の左右の側部５１、５２に設けられている当接部６２は、中央部５９側に引っ張られることとなり、被当接面４２４に対して摺接しつつ移動し、図９の（ｂ）に示すように、無荷重状態（図９の（ａ）参照）よりも、内方にずれることとなる。具体的には、左の当接部６２Ｌは右方乃至は右斜め後方に、右の当接部６２Ｒは左方乃至は左斜め後方に、スライドすることとなる。このスライド方向を、図９の（ｂ）に矢印で示す。図９の（ｂ）に示す当接部６２の被当接面４２４に対する当接位置は、図９の（ａ）に示す同当接位置よりも、内方にずれている。すなわち、各当接部６２が、相互の距離を縮めるように、被当接面４２４に対する当接位置をずらして、対応する被当接部４２に対して相対的にずれることとなる。 Further, since the central portion 59 of the back plate 5 tends to bend backward in the loaded state, the contact portions 62 provided on the left and right side portions 51 and 52 of the back plate 5 are pulled toward the central portion 59 side. As shown in FIG. 9 (b), it is displaced inward from the no-load state (see FIG. 9 (a)). Become. Specifically, the left contact portion 62L slides to the right or diagonally rearward to the right, and the right contact portion 62R slides to the left or diagonally backward to the left. This sliding direction is indicated by an arrow in FIG. The contact position of the contact portion 62 shown in FIG. 9B with respect to the contacted surface 424 is shifted inward from the contact position shown in FIG. 9A. In other words, the contact portions 62 are displaced relative to the corresponding contacted portions 42 by shifting the contact positions with respect to the contacted surfaces 424 so as to reduce the mutual distance.

このように、各係合部６１が、相互の距離を縮めるように、対応する被係合部４１に対して相対的にずれるとともに、各当接部６２が、相互の距離を縮めるように、被当接面４２４に対する当接位置をずらして、対応する被当接部４２に対して相対的にずれることにより、中央部５９に前方から荷重が掛かったときの背板の撓みが許容される。 As described above, the respective engaging portions 61 are displaced relative to the corresponding engaged portions 41 so as to reduce the mutual distance, and the respective abutting portions 62 are configured to reduce the mutual distance. By shifting the contact position with respect to the contacted surface 424 and relatively shifting with respect to the corresponding contacted part 42, the back plate can be bent when a load is applied to the central part 59 from the front. .

以上説明したように、背凭れ装置２は、着座者が凭れることにより、背板５の左右方向における中央部５９に前方から荷重が掛かったときに、各係合部６１が、相互の距離を縮めるように、対応する被係合部４１に対して相対的にずれるとともに、各当接部６２が、相互の距離を縮めるように、被当接面４２４に対する当接位置をずらして、対応する被当接部４２に対して相対的にずれる。 As described above, the backrest device 2 is configured such that when the seat occupant falls and a load is applied from the front to the center portion 59 in the left-right direction of the back plate 5, The contact positions of the abutting surfaces 424 are shifted so that the respective abutting portions 62 are contracted relative to each other so as to reduce the mutual distance. It shifts relatively with respect to the contacted part 42 to be performed.

すなわち、各当接部６２は部分的に被当接面４２４に接触している（換言すれば、被当接面４２４の一部にのみ接触している）ので、当接部６２と被当接面４２４との間の摩擦は小さい。また、各当接部６２は被当接面４２４に当接して（突き当てられて）いるだけであるので、各当接部６２の被当接面４２４に対するずれ方向は比較的自由である。このため、容易に当接部６２がずれて、背板５が撓むことが容易となり、着座者が快適な座り心地を得られる。また、各当接部６２は被当接部４２に当接する（面当てする）だけであるから、各当接部６２及び各被当接部４２は高い寸法精度が要求されず、組付作業も容易（各当接部６２及び各被当接部４２は、事実上、組付不要）である。このため、全体として、背凭れ装置２に対する寸法精度の要求が緩和され、組付作業も容易となる。 That is, each contact portion 62 is in partial contact with the contacted surface 424 (in other words, only in contact with a part of the contacted surface 424). The friction with the contact surface 424 is small. In addition, since each contact portion 62 is only in contact (abutted) with the contacted surface 424, the displacement direction of each contact portion 62 with respect to the contacted surface 424 is relatively free. For this reason, it becomes easy for the contact part 62 to shift | deviate easily, and the backplate 5 bends, and a seated person can obtain comfortable seating comfort. Further, since each contact portion 62 only contacts (contacts with) the contacted portion 42, each contact portion 62 and each contacted portion 42 does not require high dimensional accuracy, and the assembling work (Each contact portion 62 and each contacted portion 42 are virtually unnecessary to be assembled). For this reason, as a whole, the requirement of dimensional accuracy for the backrest device 2 is relaxed, and the assembly work is facilitated.

また、多数の貫通孔５６が形成された背凭れ主部５５において、着座者の腰が当たる部分に、左右方向に延びて背板５の左右の側部５１、５２を連結するとともに、貫通孔５６を有さないものとされることにより、背凭れ主部５５における他の部分よりも剛性が高くされた第１高剛性部５７と第２高剛性部５８とを備え、各当接部６２は、背板５の左右の側部５１、５２における第１高剛性部５７との連結部付近に設けられている。 Further, in the backrest main portion 55 in which a large number of through-holes 56 are formed, the left and right side portions 51 and 52 of the back plate 5 are connected to the portion where the seated person's waist hits, and the through-holes are connected. The first high-rigidity portion 57 and the second high-rigidity portion 58 that have higher rigidity than the other portions of the backrest main portion 55 by not having 56 are provided, and each contact portion 62 is provided. Is provided in the vicinity of the connecting portion with the first high-rigidity portion 57 in the left and right side portions 51 and 52 of the back plate 5.

このため、背板５に着座者が凭れたときに、着座者の腰が高剛性とされた部分で受け止められ、さらにその荷重が、左右の当接部６２、６２が左右の被当接面４２４、４２４に当接することにより、背フレーム３で受け止められるので、着座者の腰がしっかり支えられることとなる。そして、各当接部６２は、比較的自由に被当接部４２に対してずれることが可能であるため、背板５において着座者の腰が当たる部分が高剛性であるにもかかわらず撓むことが容易となり、着座者はより快適な座り心地を得られる。また、各当接部６２は被当接部４２に対して当接する（面当てする）だけであるから、撓み難く作業し難い高剛性の部分における組付作業が容易（事実上、不要）である。 For this reason, when the seated person falls on the back plate 5, the seated person's waist is received by the portion having high rigidity, and the load is applied to the left and right contact portions 62, 62 on the left and right contact surfaces. By abutting on 424 and 424, the back frame 3 can be received, so that the seated person's waist is firmly supported. Since each contact portion 62 can be displaced relative to the contacted portion 42 relatively freely, the portion of the back plate 5 against which the seated person's waist hits is highly rigid. The seated person can obtain a more comfortable sitting comfort. In addition, since each contact portion 62 only abuts (contacts with) the contacted portion 42, the assembly work in a highly rigid portion that is difficult to bend and difficult to work is easy (effectively unnecessary). is there.

また、背凭れ装置２は、各係合部６１が、対応する被係合部４１に対して係合ピン７により係合され、中央部５９に前方から荷重が掛かったときに、係合ピン７の周壁に部分的に摺接しつつ（換言すれば、係合ピン７の周壁の一部にのみ摺接しつつ）、左右の係合部６１、６１間の距離を縮めるように、対応する被係合部４１に対して相対的にずれるように構成されている。 Further, the backrest device 2 is configured such that each engaging portion 61 is engaged with the corresponding engaged portion 41 by the engaging pin 7 and a load is applied to the central portion 59 from the front. 7 is partially slidably contacted with the peripheral wall (in other words, is slidably contacted with only a part of the peripheral wall of the engaging pin 7), and the corresponding covering is made to reduce the distance between the left and right engaging portions 61, 61. It is configured to be displaced relative to the engaging portion 41.

すなわち、係合部６１が被係合部４１に対してずれるとき、係合部６１とその係合部６１を被係合部４１に係合させている取付部材（実施形態では、係合ピン７）との接触面積が小さいため、係合部６１と取付部材との間の摩擦は小さく、着座者の体重が軽い場合や、着座者の背をしっかりと支えるために背板５の剛性を高くした場合であっても、左右の係合部６１、６１間の距離が容易に縮小されることとなる。このため、背板５が、当接部６２が設けられている部位よりも上方の部位においても、適度に撓むことが可能となって、着座者がより快適な座り心地を得られる。 That is, when the engaging portion 61 is displaced with respect to the engaged portion 41, the engaging portion 61 and the mounting member that engages the engaged portion 61 with the engaged portion 41 (in the embodiment, the engaging pin). 7) Since the contact area is small, the friction between the engaging portion 61 and the mounting member is small, and the rigidity of the back plate 5 is increased when the weight of the seated person is light or when the seated person is supported firmly. Even when the height is increased, the distance between the left and right engaging portions 61, 61 is easily reduced. For this reason, it becomes possible for the back plate 5 to be appropriately bent even in a portion above the portion where the contact portion 62 is provided, so that the seated person can obtain a more comfortable sitting comfort.

以下、変形例について説明する。 Hereinafter, modified examples will be described.

上記実施形態では、無荷重状態においても各当接部６２が対応する被当接面４２４に対して当接するように構成したが、少なくとも荷重状態のときに当接すればよく、無荷重状態では、各当接部６２が、対応する被当接面４２４に対して当接せず、被当接面４２４との間に若干の隙間を有して（すなわち、接近して）配置されるように構成してもよい。このように、当接部６２及び被当接面４２４の形状は、上記したものに限られないが、少なくとも荷重状態のときに各当接部６２が対応する被当接面４２４に当接する形状とし、さらに、相互の接触面積を小として当接部６２が内方にスライドし易い形状とすることが好ましい。 In the above embodiment, each contact portion 62 is configured to contact the corresponding contacted surface 424 even in a no-load state. Each abutting portion 62 does not abut against the corresponding abutted surface 424 and is arranged with a slight gap (that is, close to) the abutted surface 424. It may be configured. As described above, the shapes of the contact portion 62 and the contacted surface 424 are not limited to those described above, but the shape in which each contact portion 62 contacts the corresponding contacted surface 424 at least in a load state. Furthermore, it is preferable that the contact area 62 is made small so that the contact portion 62 is slid inward.

また、第１高剛性部５７、第２高剛性部５８に、前後方向に貫通する貫通孔を若干設けてもよい。単位面積当たりの貫通孔の総開口面積を、背凭れ主部５５における他の部分（第１高剛性部５７と第２高剛性部５８とを除く部分）よりも小さくすれば、第１高剛性部５７、第２高剛性部５８を、他の部分よりも剛性を高いものにできるからである。なお、「総開口面積」とは、貫通孔が複数ある場合にはそれらの開口面積の合計をいう。すなわち、高剛性部は、前後方向に貫通する貫通孔を有さないもの又は単位面積当たりの貫通孔の総開口面積が相対的に小さいものとされることにより、背凭れ主部５５における他の部分よりも剛性が高くされていればよい。 Further, the first high-rigidity portion 57 and the second high-rigidity portion 58 may be provided with some through holes penetrating in the front-rear direction. If the total opening area of the through-holes per unit area is made smaller than the other part (the part excluding the first high-rigidity part 57 and the second high-rigidity part 58) in the backrest main part 55, the first high-rigidity This is because the part 57 and the second high-rigidity part 58 can have higher rigidity than other parts. The “total opening area” means the total of the opening areas when there are a plurality of through holes. That is, the high-rigidity part has no through-holes penetrating in the front-rear direction, or the total opening area of the through-holes per unit area is relatively small. What is necessary is just to make rigidity higher than a part.

また、各当接部６２を、背板５の左右の側部５１、５２における第２高剛性部５８との連結部付近に設けてもよいし、第１高剛性部５７と第２高剛性部５８との間に設けてもよい。なお、背凭れ主部５５における第１高剛性部５７、第２高剛性部５８、及び、それらの間の部分を纏めて、１つの高剛性部と捉えることもできる。そのように捉えた場合には、高剛性部は貫通孔５６を有することとなるが、単位面積当たりの貫通孔５６の総開口面積は、背凭れ主部５５における他の部分（第１高剛性部５７よりも上方の部分、及び、第２高剛性部５８よりも下方の部分）よりも小さいため、他の部分よりも剛性が高いものとなる。 Further, each contact portion 62 may be provided in the vicinity of the connecting portion between the left and right side portions 51 and 52 of the back plate 5 and the second high-rigidity portion 58, or the first high-rigidity portion 57 and the second high-rigidity portion. You may provide between the part 58. In addition, the 1st highly rigid part 57 in the backrest main part 55, the 2nd highly rigid part 58, and the part between them can be put together, and it can also be regarded as one highly rigid part. In such a case, the high-rigidity portion has the through-hole 56, but the total opening area of the through-hole 56 per unit area is the other portion of the backrest main portion 55 (first high-rigidity). Therefore, the rigidity is higher than those of the other parts.

さらに、高剛性部を、第１高剛性部５７のみにする等、１つにしてもよいし、３つ以上設けてもよい。高剛性部を複数設けた場合には、側部５１、５２において、いずれかの高剛性部の連結部付近に、当接部６２を設ければよい。 Further, the number of high-rigidity parts may be one, such as only the first high-rigidity part 57, or three or more high-rigidity parts may be provided. When a plurality of high-rigidity portions are provided, the abutment portion 62 may be provided in the vicinity of the connecting portion of any of the high-rigidity portions in the side portions 51 and 52.

また、係合ピン７の軸方向に直交する断面を、矩形状等の多角形状としてもよいし、係合部６１を被係合部４１に取り付けるための取付部材を、係合ピン７のような軸状部材としなくてもよい。さらに、係合ピン７のような別体の取付部材を用いず、被係合部４１と同体の取付部材（換言すれば、被係合部４１の一部）を用いて、係合部６１を被係合部４１に取り付けてもよい。このように、係合部６１及び被係合部４１の形状は上記したものに限られないが、係合部６１と（取付部材を用いるときは、取付部材も含めて）被係合部４１との接触面積が小さい形状であることが好ましい。また、係合部６１を被係合部４１に対し、取り付ける（係止する）のではなく、当接部６２及び被当接部４２と同様に当接（面当て）することとしてもよい。すなわち、「係合する」とは、係止する場合のみならず、単に接触している場合も含む意である。但し、背板５を背フレーム３に安定して支持させるためには、実施形態のように、係止することが好ましい。実施形態では、左右の係合部６１、６１と左右の被係合部４１、４１、左右の係止部６３、６３と左右の被係止部４３、４３のそれぞれで、係止する構造としており、すなわち、背板５は、左右上下で背フレーム３に係止されていることから、背フレーム３に安定して支持されている。 Moreover, the cross section orthogonal to the axial direction of the engaging pin 7 may be a polygonal shape such as a rectangular shape, and an attachment member for attaching the engaging portion 61 to the engaged portion 41 is like the engaging pin 7. It does not have to be a shaft-like member. Furthermore, without using a separate mounting member such as the engaging pin 7, using the mounting member that is the same body as the engaged portion 41 (in other words, a part of the engaged portion 41), the engaging portion 61. May be attached to the engaged portion 41. As described above, the shapes of the engaging portion 61 and the engaged portion 41 are not limited to those described above, but the engaged portion 61 and the engaged portion 41 (including the attaching member when an attaching member is used) are used. It is preferable that it is a shape with a small contact area. In addition, the engaging portion 61 may be abutted (surface contact) in the same manner as the abutting portion 62 and the abutted portion 42 instead of being attached (locked) to the engaged portion 41. In other words, “engage” means not only the case of locking but also the case of simply contacting. However, in order to stably support the back plate 5 to the back frame 3, it is preferable to lock as in the embodiment. In the embodiment, the left and right engaging portions 61, 61 and the left and right engaged portions 41, 41, the left and right engaging portions 63, 63, and the left and right engaged portions 43, 43 are locked. In other words, since the back plate 5 is locked to the back frame 3 on the left, right, top and bottom, it is stably supported by the back frame 3.

また、背フレーム３を金属製としてもよいし、背板５を合成樹脂以外の硬質弾性体からなるものとしてもよい。 Further, the back frame 3 may be made of metal, and the back plate 5 may be made of a hard elastic body other than the synthetic resin.

１…座体
２…背凭れ装置
３…背フレーム
５…背板
３１…（背フレームの左の）側部
３２…（背フレームの右の）側部
４１…被係合部
４２…被当接部
５１…（背板の左の）側部
５２…（背板の右の）側部
５５…背凭れ主部
５６…貫通孔
５７…第１高剛性部
５８…第２高剛性部
５９…中央部
６１…係合部
６２…当接部
４２４…被当接面
Ｃ…椅子 DESCRIPTION OF SYMBOLS 1 ... Seat body 2 ... Backrest device 3 ... Back frame 5 ... Back board 31 ... (Left side of back frame) 32 ... (Right side of back frame) 41 ... Engagement part 42 ... Abutted Part 51: Side part (left of the back plate) 52 ... Side part (right of the back plate) 55 ... Backrest main part 56 ... Through hole 57 ... First high rigidity part 58 ... Second high rigidity part 59 ... Center Part 61 ... engaging part 62 ... contact part 424 ... contacted surface C ... chair

Claims

A back frame extending upward from the rear part of the seat body, and a back plate attached to the front side of the back frame and made of a hard elastic body such as a synthetic resin,
Engaging portions are provided on the left and right sides of the back plate, respectively, and engaged portions are provided on the left and right sides of the back frame, respectively. Engaged,
Abutting portions are respectively provided in lower portions than the engaging portions of the left and right side portions of the back plate, and are respectively applied to lower portions than the engaged portions of the left and right side portions of the back frame. A contact portion is provided, and each contact portion is not pivotally attached to the corresponding contacted portion, and at least when a load is applied from the front to the center portion in the left-right direction of the back plate. Abutting from the front on the abutted surface of the abutted part,
The engagement parts are shifted relative to the corresponding engaged parts so as to reduce the mutual distance, and the contact parts are reduced so as to reduce the mutual distance. It is configured to allow the back plate to bend when a load is applied to the central portion from the front by shifting the contact position with respect to the surface and relatively shifting with respect to the corresponding contacted portion. A chair backrest device characterized by

Each contacted portion includes an upper protective wall portion protruding forward from the front surface of the back frame, and a lower protective wall portion disposed below the upper protective wall portion and protruding forward from the front surface of the back frame. Prepared,
The abutted surface included in each abutted portion is between the upper protective wall portion and the lower protective wall portion of the abutted portion, and is a front end portion and a lower portion of the upper protective wall portion. The chair backrest device according to claim 1, wherein the chair backrest device is disposed at a position rearward of the front end portion of the protective wall portion and facing forward.

The back plate includes a backrest main portion in which a large number of through holes penetrating in the front-rear direction are formed between the left and right side portions,
The backrest main portion includes one or more high-rigidity portions that extend in the left-right direction to connect the left and right side portions of the back plate to the portion where the seated person's waist hits,
The high-rigidity part has no through-holes or has a relatively small total opening area of the through-holes per unit area, so that it is more rigid than other parts of the backrest main part. Is raised,
3. The chair backrest device according to claim 1, wherein each of the contact portions is provided in the vicinity of a connection portion with the high-rigidity portion on the left and right side portions of the back plate.

A chair comprising the chair backrest device according to claim 1 , 2 or 3 .