JP2013000447A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair which allows a seat to be shaped in an optimal shape in response to a posture of a sitter while keeping a simple constitution.SOLUTION: The chair 1 includes the seat 2 which is constituted to be displaceable in a vertical direction so that the rear section 24 can be sunk downward as shown by the same figure, a supporting body 3 which supports the seat 2 in such a manner that the front end section of the seat 2 is fixed, e.g., so that the seat 2 may not tilt in a longitudinal direction, a backrest 4 which is supported by the seat 2, and an armrest 5 which is installed over the seat 2 and the backrest 4. The chair 1 also includes under the seat 2 a regulating surface 6 which regulates a deformed shape of the seat 2 owing to a change of a position in contact with the lower surface of the seat 2 in response to a displacement in the vertical direction of the rear section 24 of the seat 2.

Description

  The present invention relates to a chair that can be moved by a seated person.

  Conventionally, various chairs using a link mechanism, a plurality of springs, and the like have been proposed to change the position and shape of the seat according to the posture of the seated person. In recent years, attention has been paid to a chair configured such that the seat itself can be elastically deformed as a configuration capable of reducing the number of parts constituting the chair in combination with diversification of materials that can be used for the seat. (For example, refer to Patent Document 1).

  The chair described in the patent document uses a material that can be elastically deformed in the seat, specifically, the seat itself constituting the chair body in order to generate a posture and a tilting reaction force according to the posture of the seated person. In addition, the rear portion of the seat portion is supported by an auxiliary elastic body that is a gas spring configured to be elastically deformable by expansion and contraction, and this determines the lower end of the operation of the seat portion. Thereby, the elastic deformation of the seat portion, that is, the seat and the elastic deformation of the auxiliary elastic body are made to cooperate, so that appropriate deformation of the seat and application of the reaction force according to the posture of the seated person are possible.

  However, when considering strictly changing the seating posture of each seated person to correspond to the seating posture or shape desired by the seated person, the seat posture or shape required by each posture due to the weight movement of the seated person is a straight line. It does n’t change. Therefore, when an auxiliary elastic body is applied as in the above-mentioned patent document that performs only linear expansion and contraction in an attempt to accurately correspond the posture or shape of these seats to each posture of the seated person, a plurality of these elastic bodies can be provided, The power must be adjusted accordingly. As a result, the number of parts of the chair is increased or the structure is complicated.

JP 2000-342377 A

  The present invention focuses on the above-described points, and an object of the present invention is to provide a chair that can have an optimal shape depending on the posture of a seated person while having a simple configuration.

  In order to achieve such an object, the present invention takes the following measures.

  That is, the chair according to the present invention is a free end whose rear part can be displaced at least in the vertical direction, and the rear part is displaced in the vertical direction by the weight movement of the seated person and is configured to be deformable, and supports the seat. A regulating surface that regulates the deformed shape of the seat by changing a position in contact with the lower surface of the seat in accordance with a vertical displacement of a rear portion of the seat, below the seat. It is characterized by having.

  Here, “the position in contact with the lower surface of the seat changes” is not limited to only that the regulation surface is always in contact with any part of the lower surface of the seat. That is, it is a concept that includes the first contact with the lower surface of the seat during the displacement of the seat. Of course, it is a concept that includes not only what changes only the position in contact with the lower surface of the seat but also the meaning that the area in contact with the lower surface, that is, the area changes.

  If it is such, by changing the position which a control surface touches the lower surface of a seat by a seat occupant's weight shift, the shape of a seat changes with a control surface according to the degree to which a seat is displaced in the up-and-down direction. As a result, the shape of the seat can be set according to each posture in the weight movement of the seated person, so that the seated person can sit in a seat optimally set for each posture in the weight movement. . As a result, it is possible to realize a chair that can be deformed into an optimum shape in accordance with the posture of the seated person while having a simple configuration.

  Further, as a configuration capable of stably displacing the deformable seat, it is desirable to fix the front end of the seat to the support.

  Furthermore, if the restriction surface is provided on the support and is formed so as to be continuous from the front end of the seat, the contact position between the restriction surface and the lower surface of the seat is continuously changed by the weight movement of the seated person. The seat can be deformed smoothly.

  In addition, if the seat is made of a synthetic resin having an elastically deformable plate shape, not only the shape of the seat but also the reaction force due to the elasticity of the seat at the same time due to the change in the contact position between the regulating surface and the lower surface of the seat. Can be set.

  As a specific shape of the restriction surface for the seated person to perform comfortable weight movement in the front-rear direction, an aspect in which at least a part of the restriction surface is a convex surface bulging upward in the front-rear direction can be mentioned. .

  In addition, if at least a part of the restriction surface is a convex surface that bulges upward in the left-right direction, the seated person can smoothly move the weight in the left-right direction.

  In general, the body weight movement in the front-rear direction of the seated person often changes the body shape, that is, the posture by moving the thigh and waist, while the weight movement in the left-right direction is the angle formed by the thigh and waist In many cases, the direction of the body is simply changed without much change. In view of this, if the seat is configured so that the lateral deformation is less likely to occur than the forward / backward deformation, the seated person's buttocks and the like may feel uncomfortable due to the deformation of the seat when shifting the weight on the left / right. You do n’t have to.

  And as a suitable example of the backrest supported by the seat, what constituted the shell integrated with the back seat by the backrest and the seat is mentioned. In such a case, the rear end of the seat is continuous with the back, so that the rigidity is naturally higher than other parts.

  In particular, as an example of constituting a shell that can comfortably follow the upper body of the seated person while making the seat deformation and elastic repulsive force comfortable, an embodiment in which the shell is made of a laminated structure of an elastic resin and an elastomer is given. it can.

  ADVANTAGE OF THE INVENTION According to this invention, although it is a simple structure, the chair which can change a seat into an optimal shape according to a seated person's attitude | position can be provided.

The side view of the chair which concerns on one Embodiment of this invention. The disassembled perspective view which shows the principal part. The exploded top view which shows the principal part. The exploded rear view which shows the principal part. Operation | movement explanatory drawing corresponding to FIG. Explanatory drawing corresponding to FIG. The side view which concerns on the modification 1 of the embodiment. The perspective view which shows the principal part of the modification. The side view which shows the modification 2 of the embodiment. The side view which shows the modification 3 of the embodiment. The external view which shows the modification 4 of the embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 6, a chair 1 according to this embodiment is a case where the present invention is applied to an office rotary chair. As shown in the figure, the chair 1 has a seat 2 configured to be vertically displaceable so that the rear portion 24 can sink downward, and the front end portion of the seat 2 does not tilt in the front-rear direction, for example. The support 3 is supported by being fixed to the back, the backrest 4 supported by the seat 2, and the armrest 5 provided across the seat 2 and the backrest 4. Moreover, in this embodiment, the aspect which comprised the single shell S by forming these integrally as an example which provides said seat 2, the backrest 4, and the armrest 5 is disclosed.

  Here, the chair 1 according to the present embodiment deforms the seat 2 by changing the position in contact with the lower surface 2a of the seat 2 below the seat 2 according to the vertical displacement of the rear portion 24 of the seat 2. It has the control surface 6 which controls a shape, It is characterized by the above-mentioned.

  Hereinafter, each component of the chair 1 will be described. The chair 1 according to this embodiment has a basic configuration in which an elastically deformable shell S in which a seat 2, a backrest 4 and an armrest 5 are integrally formed is attached to the upper side of a support 3.

  As shown in FIGS. 1 to 6, the support 3 includes a leg blade 31, a leg column 32 standing from the leg blade 31, and an axis center of the leg column 72 supported by the upper end of the leg column 32. And a support base 34 capable of turning. The leg strut 33 is constituted by a gas spring, and the support base 34 is fixed to the upper end of the cylinder shaft 33 of the gas spring. The support base 34 has a trapezoidal shape in plan view that gradually becomes narrower from the front end toward the rear end, and a seat mounting surface 35 for mounting the seat 2 is formed at the front end and rearward from the seat mounting surface 35. The regulating surface 6 according to the present invention is formed. The specific shape of the restriction surface 6 will be described later.

  The shell S has a configuration in which the seat 2 and the backrest 4 are continuous, and has a configuration in which armrests 5 having curved shapes are provided on both sides of the seat 2 and on both sides of the backrest 4. In this embodiment, as the material of the shell S, a material having a laminated structure of an elastic resin whose strength is adjusted with a fiber such as glass fiber and an elastomer such as rubber is applied. As a result, the shell S has a required strength by partially adjusting the thickness, and an elastic reaction force is suppressed as compared with a configuration using only an elastic resin.

  As shown in FIGS. 1 to 5, the seat 2 is an elastically deformable plate made of the above-described synthetic resin and the like, and by appropriately setting the thickness of the material constituting the shell S, the seat 2 Has a sufficient rigidity to produce a backward tilting force. And the seat 2 has the front fitting part 21, the contact | adherence part 22, the intermediate part 23, and the rear part 24 which is a free end from the front, respectively. The front fitting portion 21 has a U shape in side view and is supported by the support body 3. In the present embodiment, the front fitting portion 21 is attached by being fitted into a seat attachment surface 35 provided at the front end of the support base 34 mainly using elastic deformation. The front fitting portion 21 and the seat mounting portion 35 may be attached together with an appropriate fastening method such as screwing in addition to the above-described fitting by fitting. In addition, since this structure can easily separate the support base 34 and the shell S at the time of disposal, the chair 1 can be easily disposed of separately. The close contact portion 22 actually refers to a region inclined slightly forward from the horizontal supporting the thigh of the seated person, and this portion is always in close contact with the support base 34 in this embodiment. The intermediate part 23 is an area mainly located at the center of the seat 2 in the front-rear direction, and is appropriately deformed by the rearward movement of the seated person. In the present embodiment, the armrests 5 are integrally continued on both sides of the intermediate portion 23. The rear portion 24 can perform a sinking operation between an initial state (p) before sinking and a subsidence state (q) where it sinks most. In the initial state (p), the rear portion 34 is moved downward. By forming a space between the two, it becomes a free end. That is, the rear portion 24 is separated from the upper surface of the support 3 in the initial state (p), and is appropriately depressed by using elastic deformation of the seat 2 in accordance with a load acting on the seat 2. In the present embodiment, the backrest 4 is continuously provided upward from the rear portion 24. In other words, the rear portion 24 exclusively supports the backrest 4. In FIG. 1, the initial state (p) is indicated by a solid line, and the subsidence state (q) is indicated by a two-dot chain line.

  The backrest 4 is formed integrally with the seat 2 by the lower part being continuous with the rear portion 24 of the seat 2. The backrest 4 includes a thick connection portion 43 which is a connection portion with the seat 2, a waist support portion 42 for mainly supporting a seated person's waist continuously above the thick connection portion 43, A thin upper portion 41 for supporting the wearer's state is provided continuously above the waist support portion 42. The thick support portion is configured to be more difficult to elastically deform than other portions by forming the material constituting the shell S thick. The waist support part 42 supports the seated person's waist part so as to wrap the back part of the seat in a plan view, so that the seated person can be seated even when the backrest 4 and the seat 2, that is, the shell S are tilted left and right. It can be supported stably. In addition, the waist support part 42 has the armrests 5 raised from both ends thereof. Thereby, in this embodiment, a part of the shell S from the rear part 24 of the seat 2 in which the armrest 5 is installed to the backrest 4 and the seat 2 from both sides to the waist support part 42 of the backrest 4 inevitably has strength. The height becomes higher so that the waist can be supported stably from the buttocks of the seated person. As a result, the seat occupant can be relieved by the stable support of the buttocks and hips regardless of whether the rear portion 24 of the seat 2 is in the depressed state (q) or tilted to the left or right. A feeling can be obtained. By providing the thin upper part 41, the upper part from the waist is set so as to be thin and soft so as to support the upper body of the seated person and not to disturb the operation of the upper body excessively.

  The armrest 5 can constitute a loop shape in a side view in a continuous manner integrally with the backrest 4 and the seat 2. Thereby, the strength in the vicinity of the connecting portion of the backrest 4 and the seat 2 is secured. The armrest 5 is formed integrally with the seat 2 and the backrest 4 as a part of the shell S in this embodiment. However, of course, the backrest 4 is not only formed integrally with the backrest 4 and the seat 2 but also provided with an armrest 5 by retrofitting a curved member to the shell S integrally formed with the backrest 2. It is good as a thing.

  Therefore, the chair 1 of the present embodiment is arranged on the upper surface of the support base 34 below the seat 2 on the lower surface 2a of the seat 2 in accordance with the above-described restriction surface 6, that is, the vertical displacement of the rear portion 24 of the seat 2. It has a regulating surface 6 that regulates the deformed shape of the seat 2 by changing the contact position.

  Hereinafter, the shape of the restriction surface 6 formed on the upper surface of the support base 34 will be mainly described in detail.

  The restriction surface 6 is formed such that the restriction surface 6 continues from the seat mounting surface 35 at the front end of the support base 34. In the present embodiment, the regulation surface 6 mainly includes a front region 61 that is slightly inclined forward, a middle region 62 that is continuous with the front region 61 and is gently inclined rearward, and slightly toward the rear end. It mainly has a rear region 63 that is largely inclined. In this embodiment, the front region is a contact surface 6a that is in close contact with the lower surface 2a of the seat 2, and the middle region 62 and the rear region 63 are formed with front and rear convex surfaces 6b that are bulged upward in the front-rear direction. By doing so, the seat 2 can be deformed in accordance with the weight shift before and after the seated person. In addition, the middle region 62 and the rear region 63 are also formed with left and right convex surfaces 6c which are curved surfaces curved upward in the left and right direction, so that the seat 2 is mainly adapted to the shape of the left and right convex surfaces 6c. The intermediate portion 23 and the rear portion 24 can be deformed by tilting left and right.

  Hereinafter, in the chair 1 of this embodiment, the deformation | transformation of the seat 2 which arises by a seated person's weight shift is demonstrated.

  First, the seat 2 is deformed so that the rear portion 24 of the seat 2 changes from the initial state (p) shown in FIG. 1 to the subsidence state (q) shown in FIG. In the first place, since the weight of the seated person is largely related from the intermediate part 23 to the rear part 24 even in the initial state (p), it quickly deforms due to the weight movement in the front-rear direction. Specifically, the lower surface 2a of the seat 2 is deformed while gradually increasing the contact area with the restricting surface 6 according to the degree of curvature of the front and rear convex surfaces. In the vicinity of the illustrated subsidence state (q), since the front and rear convex surfaces have a greater degree of inclination in the rear region 63 than in the middle region 62, the rear portion 24 of the seat 2 sinks greatly, and the backrest 4 tilts greatly rearward. At the same time, at the backrest 4, the deformation of the thin-walled upper portion 41 becomes larger than the deformation of the thick-walled curved portion and the deformation of the waist support portion 42 connecting the armrest 5. For this reason, in such a case, the deformation of the waist support portion 42 is relatively large.

  And in this embodiment, as shown in FIG. 6, it is also possible to incline by the left-right direction and a weight by forming the left-right convex surface 6c. In the figure, since the curvature of the left and right convex surfaces 6c provided in the rear region 63 is configured to be large, when the seated person puts his / her weight in the lateral direction when the rear portion 24 is set as a sinking upper body, The armrest 5 can receive the weight of the seated person, and accordingly, the lower surface 2a of the seat 2 can be greatly inclined along the curved shape of the left and right convex surfaces 6c. In particular, in the present embodiment, by providing this armrest 5, the seated person can move to the left or right while maintaining a stable state on the seat 2 while grasping or drowning on either one of the armrests 5. Therefore, a sense of stability and a sense of security can be obtained during weight transfer.

  With the configuration as described above, the chair 1 according to the present embodiment can change the position of the seat 2 in the vertical direction by changing the position where the regulating surface 6 contacts the lower surface 2a of the seat 2 due to the weight movement of the seated person. As a result of the change in the shape of the seat 2 due to the restriction surface 6 depending on the degree of movement, the shape of the seat 2 can be set according to each posture in the weight movement of the seated person. The seat 2 can be seated 2 on the seat 2 that is optimally set for the posture. As a result, it is possible to realize the chair 1 that can be deformed into an optimal shape according to the posture of the seated person while having a simple configuration.

  In particular, in the present embodiment, since the regulating surface 6 gradually deforms the seat 2 in accordance with the weight movement of the seated person, the shell is moved when the weight of the seated person is moved backward as shown in FIG. That is, the seat is gradually deformed toward the left and right when the seat moves from left to right as shown in FIG. This means that the deformed portion does not concentrate locally as compared with the conventional one in which only the front end of the seat 2 is supported by the cantilever without having the regulating surface 6, and a large deformation as a whole. Even if it is made, since each part is a thing with a small deformation | transformation continuing, an unreasonable deformation does not occur locally. That is, even if the shell S and the seat 2 are repeatedly deformed, it is unlikely to be destroyed due to fatigue or the like. That is, according to such a structure, it can be set as a highly durable thing, As a result, a chair with a long product life can be provided.

  Moreover, in order to be able to displace the seat 2 stably, in this embodiment, the front end front fitting portion 21 of the seat 2 is fixed to the support body 3.

  Further, in the present embodiment, the restriction surface 6 is provided on the support 3 and the restriction surface 6 is formed so as to be continuous from the front end of the seat 2. The seat 2 can be smoothly deformed by changing the position of contact with the lower surface 2a of 2.

  In addition, in this embodiment, since the seat 2 is made of a synthetic resin having a plate shape that can be elastically deformed, not only the shape of the seat 2 but also the change of the contact position between the regulating surface 6 and the lower surface 2a of the seat 2, The reaction force due to the elasticity of the seat 2 can be set at the same time.

  In this embodiment, a front and rear convex surface bulging upward in the front-rear direction is formed as a specific shape of the regulating surface 6 for the seated person to comfortably move the weight in the front-rear direction.

  In addition, in the present embodiment, the left and right convex surfaces 6c bulging upward in the left-right direction are formed as the restricting surface 6, so that the seated person can ensure the deformation of the seat 2 that can smoothly move the weight in the left-right direction. .

  In this embodiment, specifically, the shell S formed integrally with the seat 2 is applied so that the displacement of the rear portion 24 of the seat 2 can be directly connected to the posture of the seated person as it is. In addition, this configuration naturally increases the rigidity of the rear portion 24 of the seat 2 which is a boundary portion with the backrest 4 of the seat 2. In addition, in the present embodiment, the thickness of the thick connecting portion 41 is set to be larger than that of other portions of the shell 2, and the operation of the shell S sufficient to give a sense of security to the seated person even when the weight of the seated person is moved is realized. is doing.

  In addition, in the present embodiment, moderate elasticity and texture are imparted to the seated person as an aspect in which the shell S has a laminated structure of elastic resin and elastomer. In particular, in the present embodiment, by setting the thickness of the shell S to be appropriately different depending on the portion of the shell S, a place where the seated person should be supported stably and a place where the seated person can easily follow are provided as appropriate. A comfortable seating for the elderly is realized.

<Modification 1>
Below, each modification of this embodiment is demonstrated. In addition, about each of these modified examples, the same code | symbol is attached | subjected to the thing corresponded to the component of the said embodiment, and the detailed description shall be abbreviate | omitted suitably.

  The chair 1 shown in FIG.7 and FIG.8 makes the middle area | region 62 of the control surface 6 the notch plane 6d cut out planarly. Accordingly, in the initial stage of the backward tilting operation of the seated person, only the deformation due to the elasticity of the seat 2 itself is allowed, and the deformation of the seat 2 can be controlled by the left and right convex surfaces 6c provided in the rear region 63 in the vicinity of the subsidence state (q). Yes.

  That is, the restriction surface 6 according to the present embodiment is not limited to a mode in which the position where the seating person gradually touches the lower surface 2a is always different according to the weight movement of the seated person, but also the lower surface 2a is contacted only in a required operation region. It is good also as what can control.

<Modification 2>
Further, as shown in FIG. 9, the chair 1 according to the second modified example is provided on the lower surface 2 a of the seat 2 by providing a plurality of horizontal members 64 protruding from the middle region 62 to the rear region 63 of the restriction surface 6. On the other hand, an intermittent contact surface 6e capable of intermittent contact is provided. The intermittent contact surface 6e allows the seated person to feel light vibrations from the seat 2 every time the horizontal member 64 contacts the lower surface 2a of the seat 2 during the backward tilting operation.

  Even in such a case, it is possible to control the deformation of the seat 2 in accordance with the arrangement and shape of the horizontal member 64. Although not shown, if the lower surface 2a of the seat 2 is provided with irregularities or the like so as to correspond to the intermittent contact surface 6e, the seat 2 is tilted backward, that is, when the weight is moved backward or when the weight is moved left and right. Stable support is possible.

<Modification 3>
As shown in FIG. 10, the chair 1 according to the third modified example is provided with the rotation support portion 36 at the front end portion of the support base 34, and the front region 61 and the middle region 62 of the regulation surface 6 are formed as the cut-out plane 6 d. Thus, in the first half of the backward tilting operation, the seat 2 itself can be rotated. In the case of the seat 2, the load tends to concentrate in the vicinity of the rotation support portion. Therefore, the front portion 22 and the intermediate portion 23 that are continuous with the front fitting portion 21 of the seat 2 rotate without being in close contact with the regulation surface 6. In this configuration, the restricting surface 6 is in contact with the lower surface 2a only in the subsidence state (q), and the deformation of the seat 2 related to the right and left weight movement by the left and right convex surfaces 6c is allowed.

  That is, the chair 1 according to the present embodiment is not limited in any way as long as the seat 2 is supported by the support 3.

<Modification 4>
In the chair according to the fourth modification, a rib 2r extending in the left-right direction protrudes from the lower surface 2a of the seat 2. By providing a plurality of ribs 2r at intervals in the front-rear direction, deformation in the left-right direction is less likely to occur than deformation in the front-rear direction. As a result, when the seated person puts his / her weight in the left / right direction, the seat 2 is deformed so that the seat 2 is curved in the left / right direction on the left / right convex surface 6c, and an unexpected protruding feeling is given to the seated person's buttocks and the like. The problem of giving is effectively eliminated, and the seat 2 is generally twisted and deformed in the left-right direction.

  Although the embodiment of the present invention has been described above, the specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the aspect in which the backrest supported exclusively by the seat is disclosed, but of course, the backrest supported by the support and provided separately from the seat may be provided.

  In each of the embodiments, only the shape in which the degree of protrusion of the convex surface is gradually increased from one side to the other direction is disclosed. When a convex surface is provided and the weight is moved to the rearmost side, the shape of the regulation surface may be conversely stable in the left-right direction. As described above, the specific shape of the restricting surface may be appropriately changed to achieve a desired deformed shape of the seat on both the front, rear, left and right convex surfaces. In addition, specific modes such as the shape of the support, the backrest, and the shape of the armrest are not limited to those of the above-described embodiment, and various modes including the existing ones can be applied.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention can be used as a chair whose seat can be operated by a seated person.

DESCRIPTION OF SYMBOLS 1 ... Chair 2 ... Seat 2a The lower surface (lower surface) of a seat
21 ... front end of seat (front fitting part)
24 ... Rear part, free end (free end)
3 ... Support 4 ... Backrest 43 ... Boundary part (thick connection)
6 ... Regulating surface 6b ... Convex surface (front and rear convex surface)
6c ... convex surface (left and right convex surface)
S ... Shell

Claims (9)

A chair provided with a seat that is configured so that the rear portion is a free end that can be displaced at least in the vertical direction, and the rear portion is displaced in the vertical direction by moving the weight of the seated person and is deformable, and a support that supports the seat. There,
A chair having a regulating surface that regulates a deformed shape of the seat by changing a position in contact with a lower surface of the seat according to a vertical displacement of a rear portion of the seat below the seat. The chair according to claim 1, wherein a front end of the seat is fixed to the support body. The chair according to claim 1 or 2, wherein the restriction surface is provided on the support body, and the restriction surface is formed so as to be continuous from a front end of the seat. The chair according to claim 1, 2, or 3, wherein the seat is made of a synthetic resin having an elastically deformable plate shape. The chair according to claim 1, 2, 3, or 4, wherein at least a part of the regulating surface is a convex surface that bulges upward in the front-rear direction. The chair according to claim 1, 2, 3, 4 or 5, wherein at least a part of the regulating surface is a convex surface bulging upward in the left-right direction. The chair according to claim 1, 2, 3, 4, 5, or 6, wherein the seat is configured such that deformation in the left-right direction is less likely to occur than deformation in the front-rear direction. The chair according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the chair has a backrest, and the backrest and the seat constitute a shell integrated with the back seat. The chair according to claim 8, wherein the shell has a laminated structure of an elastic resin and an elastomer.

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