chair

Abstract

To provide a chair capable of improving suitably an appearance of a backrest supported by a support medium.SOLUTION: There is provided a chair in which a backrest C is supported by a support medium A. The support medium A includes front legs 12 arranged in pairs on the left and right, rear legs 11 arranged in pairs on the left and right, and a rear extension part 14 extended rearward from the front legs 12 on the left and right. A lower end part of the backrest C is provided with an opening M opened forward, and capable of communicating with a space sp formed inside, and the rear extension part 14 is inserted engageably with the opening M.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a chair that is suitable for use in an office or the like. [Background technology]

[0002] 2. Description of the Related Art Chairs having a backrest supported by a support body have been known in the art (see, for example, Patent Document 1).

[0003] This type of chair has a frame insertion hole at the lower end of the backrest that is open only downwards, and the backrest can be supported on the support by inserting a frame member provided on the support into the frame insertion hole at the lower end of the backrest.

[0004] However, in such a configuration, the shape of the frame material in the support body tends to extend vertically so as to be continuous with the longitudinal direction of the backrest, which is one factor that impairs the excellent design. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-82684 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in light of the above circumstances, and has an object to provide a chair that can provide a favorable appearance for at least the backrest supported by the support body. [Means for solving the problem]

[0007] That is, the present invention has the following configuration.

[0008] The invention described in claim 1 is a chair with a backrest supported by a support, the support having a pair of front legs arranged on the left and right, a pair of rear legs arranged on the left and right, and a rear extension portion extending rearward from the left and right rear legs or the left and right front legs, the lower end of the backrest is provided with an opening that is open forward and can communicate with a space formed inside, and the rear extension portion is inserted so as to be able to engage with this opening. A second back panel connecting portion is provided at the rear end of the rear extension portion so as to protrude inward, and a second fitting recess is formed in the backrest, which constitutes the space and into which the second back panel connecting portion is fitted. It's a chair.

[0009] The invention described in claim 2 is a chair having a backrest and a seat supported by a support, the support having a pair of front legs arranged on the left and right, a pair of rear legs arranged on the left and right, and a rear extension portion extending rearward from the left and right rear legs or the left and right front legs, the lower end of the backrest is provided with an opening that is open forward and can communicate with a space formed inside, the rear extension portion is inserted so as to be able to engage with this opening, and the rear extension portion is disposed outside the seat body having the seating surface of the seat in a plan view, The seat is connected to the rear extension portion via an axis member so as to be rotatable between a use position in which a seated person can sit and a standing position in which the seated person stands upright relative to a floor surface, and when the seat is in the standing position, the seat is configured to be stackable in the front-rear direction on the floor surface with other chairs having the same structure, The chair has a first back panel connection portion extending upwardly provided at the rear end of the rear extension portion, and a first fitting recess that defines the space and into which the first back panel connection portion is fitted is formed in the backrest.

[0011] Claim 3 The invention described in claim 2 is characterized in that a screw insertion hole penetrating in the vertical direction is provided in the second back plate connection portion, and the backrest is attached to the support by screwing a screw inserted into this screw insertion hole into a nut portion facing the second fitting recess. 1 This is the chair described.

[0012] Claim 4 The invention described in claims 1 and 2 is characterized in that the space is surrounded by a front wall that can form the front surface of the backrest, a side wall that can form the side surface of the backrest, and a rear wall that can form the back surface of the backrest, and the opening edge of the opening includes the front end edge of the side wall. orThis is the chair described in 3.

[0013] Claim 5 The invention described in claims 1, 2 and 3 is characterized in that the lower end of the left-right middle part of the backrest is located below the seating surface of the seat. or This is the chair described in 4. Effect of the Invention

[0014] As described above, according to the present invention, it is possible to provide a chair that can provide a favorable appearance for at least the backrest supported by the support body. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 4 is a right side view showing a stacked state in the embodiment. [Figure 8] FIG. 4 is a right side view showing a stacked state in the embodiment. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] 10 is a view seen in the X direction in FIG. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. [Figure 16] FIG. [Figure 17] FIG. 4 is a central cross-sectional view of the leg tip portion in the embodiment. [Figure 18] FIG. [Figure 19] FIG. [Figure 20] FIG. [Figure 21] FIG. [Figure 22] FIG. 1 is a perspective view showing an embodiment of the present invention. [Diagram 23] FIG. [Figure 24] Cross-sectional view taken along line YY in Figure 16. [Diagram 25] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, one embodiment of the chair will be described with reference to Figs.

[0017] The chair of this embodiment has a seat B supported via a shaft member J so as to be rotatable between a seating position (H) in which the seat can be seated on a support A and a standing position (K) in which the seat is raised relative to the floor surface.

[0018] The chair is configured so that it can be stacked in the front-to-back direction on the floor with other chairs of the same structure when seat B is in the upright position (K). Furthermore, the chair is configured so that it can be stacked in the up-down direction with other chairs of the same structure when seat B is in the usage position (H). In other words, this chair is configured so that it can be stacked in both the front-to-back direction and the up-to-down direction.

[0019] The chair comprises a support body A having a pair of left and right leg components 1 formed by aluminum die casting, a seat B rotatably supported on the support body A via an axis member J, and a backrest C supported on the support body A.

[0020] Each component of this chair will be described in detail below.

[0021] <<Support A>> The support body A comprises left and right leg constituent members 1 which are paired on the left and right and formed by injection molding, i.e., aluminum die casting, and a joint material 2 which is formed from a separate member from the left and right leg constituent members 1 and is interposed between the left and right leg constituent members 1 to connect them together.

[0022] <Leg component 1> The left and right leg components 1 are substantially symmetrical. The left and right leg components 1 are each integrally formed by die-casting aluminum. The left and right leg components 1 include a rear leg 11, a front leg 12 integrally extending forward from the inner portion of the upper end of the rear leg 11, a joint portion 13 extending inward from the upper portion of the front leg 12 and having a tip portion connected to a side end portion of the joint material 2, and a rear extension portion 14 extending backward from the rear end of the front leg 12 and having a portion to which the seat B and the backrest C can be connected.

[0023] The rear legs 11 extend in the vertical direction. The rear legs 11 extend in a generally straight line in the vertical direction with a forward tilt in side view. The rear legs 11 are tilted so that their lower portions are positioned more outward than their upper portions in front and rear views. Casters 17 are provided at the lower ends of the rear legs 11. The rear legs 11 are formed with a first smooth surface 11m facing upward at their upper ends, which is flush with a second smooth surface 12m that is the upper surface of the upper front leg portion 12b of the front legs 12 and a third smooth surface 14m that is the upper surface of the rear extension portion 14.

[0024] The front legs 12 each include an inclined front leg 12a extending linearly in a backward tilted position in a side view, and an upper front leg 12b extending in the front-rear direction in a more backward tilted position than the inclined front leg 12a and connecting the upper end of the inclined front leg 12a to the upper end of the rear leg 11. The front legs 12 extend in a substantially vertical direction in front and rear views. Casters 17 are provided at the lower ends of the front legs 12.

[0025] 22, the caster 17 has a recess 17c formed by a caster body 17a rotatably connected to the rear leg 11 and the front leg 12, and wheels 17b provided on the left and right sides of the caster body 17a. As shown in the figure, the recess 17c of the caster 17 can be engaged so as to straddle the rear leg 11 and the front leg 12 of another chair having the same structure, so as to stabilize the stacking position when stacked vertically.

[0026] A retaining projection t1 capable of retaining the front damper F is integrally provided on the rear side of the vertically intermediate portion of the inclined front leg 12a so as to protrude rearward. The retaining projection t1 is provided with a nut portion n1 into which a screw v1 for mounting the front damper F is screwed.

[0027] The front damper F attached to the rear of the inclined front leg 12a is made of, for example, hard rubber and has a substantially trapezoidal shape in a side view. The front damper F can abut against the front leg 12 of another chair when stacking it vertically with another chair having the same structure. The front damper F can perform a buffering function with respect to the other chair when stacking and a positioning function with respect to the other chair. The abutment surface fs of the front damper F that can abut against the front end surface of the front leg of the other chair has a concave shape relative to the curved shape of the front end surface of the front leg of the other chair. In other words, the abutment surface fs of the front damper F is configured to be able to abut against the front end surface of the front leg of the other chair in a planar manner, and is configured to be unlikely to shift when stacked.

[0028] The front damper F is formed with a retaining piece disposing slit f1 into which the retaining piece t1 of the inclined front leg 12a is inserted, and a screw insertion hole h1 communicating with the retaining piece disposing slit f1 is drilled on the inside. In other words, the front damper F is fixed to the front leg 12 by screwing a screw v1 inserted into the screw insertion hole h1 into a nut portion n1 of the retaining piece t1.

[0029] The upper front leg portion 12b is formed with a second smooth surface 12m facing upward. The second smooth surface 12m is substantially flush with the first smooth surface 11m of the rear leg 11 and a third smooth surface 14m which is the upper surface of the rear extension portion 14. Nut portions n6 are provided at two locations, front and rear, on the lower surface side of the upper front leg portion 12b.

[0030] The joint part 13 protrudes inward from the upper part of the front leg 12 as an integral part. The joint part 13 extends from the inner surface side of the upper front leg part 12b of the front leg 12. The joint part 13 has a tip part 13a with a screw insertion hole h2 penetrating in the left-right direction. The tip part 13a of the joint part 13 has a shape that can be fitted into the joint material 2.

[0031] The joint parts 13 are located behind the inclined front leg part 12a of the front leg 12, below the upper front leg part 12b, and in front of the rear leg 11. Therefore, the screw insertion holes h2 through which the screws v2 for attaching the joint material 2 are inserted are disposed in suitable positions that do not interfere with the front leg 12 and the rear leg 11. Furthermore, by providing the joint parts 13 at the above-mentioned locations, the left and right leg constituent members 1 can be connected via the joint material 2 in a manner with excellent strength.

[0032] The tip portion 13a of the joint portion 13 is adapted to be fitted into a recessed portion 21 provided at the end of the joint material 2. The leg component 1 having the joint portion 13 is connected to the joint material 2 by screwing a screw v2 inserted into a screw insertion hole h2 of the tip portion 13a of the joint portion 13 into a nut portion (not shown) provided at the end of the joint material 2.

[0033] A recessed portion 13b, which also serves as a passage for the screw v2, is formed in the lower surface of the joint portion 13. A nut portion n7 and a screw insertion hole h2 are disposed in a position facing the recessed portion 13b.

[0034] In this embodiment, the upper front leg 12b and the joint 13 constitute an option mounting section R to which an optional armrest D, memo stand E, etc. can be attached. That is, a plurality of nut sections n6, n7 are provided on the undersides of the upper front leg 12b and the joint 13, and the armrest D and memo stand E can be attached to the support A by screwing the support connection sections d1, e1, which are the base ends of the armrest D and memo stand E, to the nut sections n6, n7 of the upper front leg 12b and the joint 13.

[0035] The rear extension 14 extends rearward integrally from the rear end of the upper front leg 12b of the front leg 12. The upper front leg 12b and the rear extension 14 extend linearly in the front-to-rear direction in a side view. The rear extension 14 has a rectangular columnar shape as a whole. The rear end of the rear extension 14 is inserted so as to engage with an opening M formed in the front surface of the backrest C. In other words, the rear end of the rear extension 14 is inserted into a space sp formed inside the backrest C through the opening M formed in the front surface of the backrest C.

[0036] The rear extension 14 is provided with a holding portion 14a on the inner surface of the middle portion in the front-rear direction for rotatably supporting the seat B. The holding portion 14a has a bottomed hole shape that is open inward. The outer end of the shaft member J for axially supporting the seat B is secured to the holding portion 14a.

[0037] A flat positioning piece t2 is provided between the outer surface of the front end of the rear extension 14 and the back surface of the upper end of the rear leg 11 so as to connect them. The positioning piece t2 is inserted into a positioning piece arrangement slit g21 provided in the rear damper G, and can position the rear damper G at a predetermined position.

[0038] Here, the rear damper G is made of, for example, hard rubber, and is attached to the underside of the rear extension portion 14 using a screw v3. The rear damper G includes an inner damper part g1 which is attached to the underside of the rear extension portion 14 and has a screw insertion hole h3 through which the screw v3 is inserted, and an outer damper part g2 which has a positioning piece arrangement slit g21 which is integrally extended outward from the inner damper part g1.

[0039] The rear damper G is fixed to the rear extension portion 14 by screwing a screw v3 inserted through a screw insertion hole h3 provided in the inner damper portion g1 into a nut portion n3 provided on the underside of the rear extension portion 14.

[0040] The rear damper G can provide a buffer function for other chairs when stacking, and a positioning function for other chairs. The rear damper G can come into contact with the support A of other chairs when stacking with other chairs of the same structure both in the vertical direction and in the front-to-rear direction.

[0041] When stacking vertically, the back surface of the outer damper portion g2 of the rear damper G can abut against the front surface of the rear leg 11 of another chair. When stacking front-rear, the bottom surface of the inner damper portion g1 of the rear damper G can abut against the top surface of the upper front leg 12b of another chair.

[0042] A first back panel connection part 15 extending upward is integrally provided at the rear end part of the rear extension part 14. The first back panel connection part 15 is a rectangular plate extending upward from the upper part at the rear end part of the rear extension part 14. The first back panel connection part 15 is formed so that the width dimension and thickness dimension gradually decrease toward the top. The first back panel connection part 15 is adapted to be fitted into a first fitting recess s2 formed in the backrest C.

[0043] The rear end of the rear extension 14 is provided with a second back panel connection part 16 that protrudes inward. The second back panel connection part 16 has a rectangular column shape that extends inward from the inner part at the rear end of the rear extension 14. The second back panel connection part 16 is adapted to be fitted into a second fitting recess s3 formed in the backrest C. The second back panel connection part 16 is provided with a screw insertion hole h4 that penetrates in the vertical direction. The backrest C is adapted to be attached to the support body A by screwing a screw v4 inserted into the screw insertion hole h4 of the second back panel connection part 16 into a nut part n4 facing the second fitting recess s3.

[0044] The upper surface of the rear extension 14 is provided with a third smooth surface 14m which is a smooth surface. The third smooth surface 14m is flush with the first smooth surface 11m of the rear leg 11 and the second smooth surface 12m of the front leg 12. The first, second and third smooth surfaces 11m, 12m and 14m provided on the left and right leg components 1 respectively face diagonally upward and forward so as to be easily visible to the user, and can give the user a smart impression without any unevenness.

[0045] Furthermore, the upper front leg portion 12b and the rear extension portion 14 are formed integrally and extend in a straight line in the front-to-rear direction at an angle so that the front portion is lower than the rear portion when viewed from the side. Therefore, when stacked in the front-to-rear direction, the chair is positioned so as to follow the upper front leg portion 12b and rear extension portion 14 of other chairs having the same structure.

[0046] <Joint material 2> The joint material 2 is in the shape of a rectangular column extending in the left-right direction. The joint material 2 can function as a seat support that can support the seat B from below in the usage position (H). The joint material 2 is in the shape of a substantially rectangular column extending in the left-right direction. The joint material 2 plays a role in connecting the left and right leg constituent members 1.

[0047] The lower part of the seat B in the usage position (H), more specifically, the tips of the left and right protrusions 32 protruding from the seat shell 3S, are adapted to come into contact with the upper surfaces of both ends of the joint material 2 via the buffer bodies kt. The joint material 2 is provided with nut parts (not shown) into which the screws v2 inserted from the outside can be screwed into the recessed parts 21 provided on both the left and right ends.

[0048] <<Location B>> Seat B is supported rotatably via an axis member J with respect to support body A between a usage position (H) in which a person can sit and a standing position (K) in which it stands upright relative to the floor. Seat B is configured so that its position can be changed between the usage position (H) in which it can be stacked up and down with other chairs of the same structure, and the standing position (K) in which it can be stacked back and forth with other chairs of the same structure. Seat B is connected to the rear extension 14 of support body A via axis member J.

[0049] The seat B comprises a seat body 3 consisting of a shell-shaped synthetic resin seat shell 3S with a cushion 33 placed on top, and a synthetic resin under-seat frame 4 capable of supporting the seat body 3. The under-seat frame 4 is connected at its left-right middle portion to the seat shell 3S, and at its left and right ends to the support body A via shaft members J.

[0050] <Seat body 3> The seat body 3 comprises a seat shell 3S, a cushion 33 supported by the seat shell 3S, and an upholstery 34 covering the outer surface of the cushion 33 and having an edge te accommodated in an accommodating groove mz provided on the underside of the seat shell 3S.

[0051] The seat shell 3S comprises a seat shell body 31 constituting the main part having a downwardly bulging shape, and protrusions 32 as support body connecting parts protruding in pairs on the left and right sides of the underside of the seat shell body 31. The seat shell body 31 and the protrusions 32 constituting the seat shell 3S are integrally formed from synthetic resin.

[0052] The seat shell body 31 is generally rectangular in plan view. The seat shell body 31 has upright wall-like ribs rb extending in the front-rear, left-right, and diagonal directions on the upper surface side. The seat shell body 31 has an accommodation groove mz formed around the entire periphery near the periphery on the lower surface side, capable of accommodating the edge te of the upholstery 34.

[0053] In this embodiment, both side ends of the rear part of the seat shell body 31 are provided at positions capable of preventing the shaft member J from coming off the seat under frame 4.

[0054] A recess 31a that is open downward is formed on the underside of the rear part of the seat shell main body 31 for attaching the seat shell connecting part 41 of the seat under frame 4. The recess 31a is recessed upward. The seat shell 3S is positioned relative to the seat under frame 4 by fitting the recess 31a into the upper part of the seat shell connecting part 41 of the seat under frame 4.

[0055] The recess 31a is formed at a position where the upholstery 34 can be avoided, that is, inside the accommodation groove mz that is provided in an annular shape when viewed from the bottom. The seat shell body 31 is provided with a screw insertion hole h5a that penetrates in the vertical direction between the upper surface side and the lower surface side. A plurality of screw insertion holes h5a are provided at positions corresponding to the recess 31a.

[0056] A nut n5 is provided at a location corresponding to the screw insertion hole h5 on the upper surface side of the seat shell body 31. The nut n5 provided on the upper surface side of the seat shell body 31 is adapted to receive a screw v5 inserted through a screw insertion hole h5b provided in the under-seat frame 4 and a screw insertion hole h5a provided in the seat shell 3S.

[0057] The projection 32 projects downward from the underside of the center in the front-rear direction of the seat shell main body 31. A buffer body kt is provided at the tip of the projection 32.

[0058] The cushion 33 is made of a known material such as urethane foam and has a certain degree of elastic resilience. The cushion 33 is placed on the seat shell 3S.

[0059] The upholstery 34 is mainly made of fabric and covers the upper surface and peripheral edge of the cushion 33 as well as the peripheral edge of the seat shell 3S. The edge te of the upholstery 34 is accommodated in an accommodating groove mz provided around the entire periphery of the underside of the seat shell 3S near the peripheral edge.

[0060] <Underseat Frame 4> The seat frame 4 is made of synthetic resin and extends in the left-right direction. The seat frame 4 is formed separately from the seat shell 3S.

[0061] The under-seat frame 4 includes a seat shell connection part 41 that extends in a substantially straight line in the left-right direction and has its upper surface attached to the underside of the seat shell 3S, and left and right extending arm parts 42 that extend outward from both left and right ends of the seat shell connection part 41 and have shaft member holding holes u2 at their tips that can hold the shaft member J.

[0062] The seat shell connection portion 41 has a plurality of screw insertion holes h5b penetrating in the vertical direction. The seat under frame 4 can be connected to the seat shell 3S by inserting the screw v5 inserted into the screw insertion hole h5b into the screw insertion hole h5a provided in the seat shell 3S and then screwing it into the nut n5, which is a nut portion arranged on the seat shell 3S.

[0063] The left and right extending arm portions 42 extend outwardly so as to be positioned gradually rearward and gradually upward.

[0064] The outer ends of the left and right extending arm portions 42 are provided with shaft member holding holes u2 capable of holding a shaft member J for rotatably supporting the seat B. A flange portion j1 ​​is formed on the inner end of the shaft member J. The flange portion j1 ​​of the shaft member J is adapted to be attached to the opening edge on the inner surface side of the shaft member holding hole u2.

[0065] The seat frame 4 is formed of a resin having higher rigidity than the seat shell 3S. The seat frame 4 is molded from a resin having higher rigidity, such as reinforced nylon, and cooperates with the shaft members J that are directly attached to the left and right leg components 1 to prevent the left and right leg components 1 from separating from each other.

[0066] <<Backrest C>> The backrest C has a surface that can be pressed against the back of the seated person and is generally rectangular in shape when viewed from the front. The backrest C is a so-called back plate type, and is made of synthetic resin in a plate shape as a whole. In this embodiment, the lower end ce of the backrest C in the left-right middle part is located below the seating surface zm of the seat B.

[0067] The lower end of the backrest C is provided with a pair of openings M on the left and right, which are open forward and communicate with the rear extension accommodating space s1, which is a space sp formed inside, and the space formed by the first and second fitting recesses s2 and s3. The rear end of the rear extension 14 is adapted to be inserted into the openings M, the lower part of which is open. The left and right rear extensions 14 capable of supporting the backrest C are inserted so as to be engaged with the left and right openings M, respectively.

[0068] The space sp formed inside the backrest C is surrounded by a front wall c1 that can form the front surface of the lower part of the backrest C, a side wall c2 that can form the side surface of the lower part of the backrest C, and a rear wall c3 that can form the back surface of the lower part of the backrest C. The front wall c1 has an opening M that can be opened forward and outward by cutting out a rectangular corner of the lower end.

[0069] That is, the space sp provided inside the backrest C is adapted to accommodate a portion capable of supporting the backrest C. The space sp of the backrest C is composed of a space portion formed by a rear extension accommodating section s1 in which the rear end of the rear extension 14 is accommodated, a first fitting recess s2 formed on the rear extension 14 and into which the first back panel connecting section 15 is fitted, and a second fitting recess s3 located inside the rear extension accommodating section s1 and into which the second back panel connecting section 16 is fitted.

[0070] The opening edge of the opening M into which the rear extension 14 is inserted and into which the outer surface of the rear extension 14 can engage is composed of outer and inner side opening edges m1, m2 extending in the vertical direction, and an upper opening edge m3 extending in the left-right direction connecting the upper ends of the outer and inner side opening edges m1, m2. The outer side opening edge m1 is composed of the front edge at the lower end of the side wall c2.

[0071] The backrest C is provided with a nut portion n4 at a position facing the second fitting recess s3. The nut portion n6 is adapted to receive a screw v4 inserted into the screw insertion hole h4 of the second back panel connection portion 16. That is, the backrest C is attached to the support body A by screwing the screw v4 inserted into the screw insertion hole h4 of the second back panel connection portion 16 into the nut portion n4 facing the second fitting recess s3.

[0072] <Leg tip part S> This chair can be provided with leg tip members S each having a planar contact surface s11 that faces downward and contacts the floor surface, instead of the casters 17 provided on the rear legs 11 and the front legs 12. In other words, this chair can be selected between a specification in which casters 17 are provided on the lower ends of the rear legs 11 and the front legs 12, and a specification in which casters 17 are not provided on the lower ends of the rear legs 11 and the front legs 12 (i.e., a specification in which leg tip members S are provided), without changing the shape of the leg constituent members 1.

[0073] The leg tip member S is adapted to be attached to the lower end of the inclined front leg portion 12a of the rear legs 11 and the front legs 12. The leg tip member S extends generally in the same direction as the longitudinal direction of the inclined front leg portion 12a of the rear legs 11 and the front legs 12, i.e., in an oblique direction. Note that although Figures 16 and 17 show the leg tip member S attached to the inclined front leg portion 12a of the front legs 12, it can also be attached to the rear legs 11 in the same manner.

[0074] The leg tip member S comprises a leg tip member body s1 made of synthetic resin extending in the same direction as the longitudinal direction of the inclined front leg portion 12a of the front leg 12 and having a horizontal contact surface s11 formed at its lower end, and a connecting support s2 which is erected in a substantially vertical direction in the center of a substantially horizontal base portion s12 formed at the top of the leg tip member body s1 and inserted into a mounting hole u1 provided at the lower end of the inclined front leg portion 12a.

[0075] The leg tip member main body s1 has an upright wall s13 formed on the outer side of the base portion s12. The upright wall s13 is capable of covering the outer side of the lower end portion of the inclined front leg portion 12a.

[0076] The connecting support s2 has a support body s21 extending in the vertical direction and a rotation-stopping protrusion s22 protruding laterally from the support body s21. The connecting support s2 with the protrusion s22 is inserted into a keyhole-shaped mounting hole u1 provided at the lower end of the front leg 12 and the rear leg 11, so that the obliquely extending leg tip member S does not rotate relative to the front leg 12 and the rear leg 11.

[0077] <<Armrest D·Memo stand E>> In the chair of this embodiment, an armrest D and a memo pad E can be attached to the support A as options, as shown in FIGS.

[0078] The armrest D comprises a support body connection part d1 provided at the lower end and attached to the optional mounting part R, an arm part d2 extending upward from the outer end of the support body connection part d1, and an elbow rest part d3 extending rearward from the upper end of the arm part d2, the upper surface of which serves as an elbow rest surface.

[0079] The support body connection part d1 of the armrest D is provided with a screw insertion hole h6 into which a screw v6 that screws into the nut part n6 of the upper front leg part 12b is inserted, and a screw insertion hole h7 into which a screw v7 that screws into the nut part n7 of the joint part 13 is inserted. The rear part of the support body connection part d1 is adapted to fit into the recessed part 13b of the joint part 13 for positioning.

[0080] The support body connection portion d1 of the armrest D comprises a first connection block portion d11 extending along the upper front leg portion 12b, a second connection block portion d12 extending from the front end portion of the first connection block portion d11 in a direction approximately perpendicular to the first connection block portion d11 and fitted into the recessed portion 13b of the joint portion 13, and a reinforcing connecting portion d13 connecting the lower ends of the first and second connection block portions d11, d12.

[0081] The first and second connection block portions d11 and d12 constituting the support body connection portion d1 are substantially L-shaped. The reinforcing connection portion d13 is substantially triangular.

[0082] The memo stand E comprises a support connection part e1 provided at the lower end and attached to the option mounting part R, an arm part e2 extending upward from the outer end of the support connection part e1, and a top plate e4 supported at the upper end of the arm part e2 via a pivoting support mechanism e3 that can rotate in two axial directions.

[0083] The support connection part e1 of the memo stand E is provided with a screw insertion hole h6 into which a screw v6 that screws into the nut part n6 of the upper front leg part 12b is inserted, and a screw insertion hole h7 into which a screw v7 that screws into the nut part n7 of the joint part 13 is inserted. The rear part of the support connection part e1 is adapted to be fitted into the recessed part 13b of the joint part 13 for positioning.

[0084] The support connection portion e1 of the memo stand E has a structure similar to that of the support connection portion d1 of the armrest D.

[0085] The support connection portion e1 of the memo stand E comprises a first connecting block portion e11 extending along the upper front leg portion 12b, a second connecting block portion e12 extending from the front end portion of the first connecting block portion e11 in a direction approximately perpendicular to the first connecting block portion e11 and fitted into the recessed portion 13b of the joint portion 13, and a reinforcing connecting portion e13 connecting the lower ends of the first and second connecting block portions e11, e12.

[0086] The first and second connection block portions e11 and e12 constituting the support body connection portion e1 are substantially L-shaped. The reinforcing connection portion e13 is substantially triangular.

[0087] As described above, the chair according to this embodiment has a backrest C supported by a support A. The support A has front legs 12 arranged in a pair on the left and right, rear legs 11 arranged in a pair on the left and right, and rear extensions 14 extending rearward from the left and right front legs 12. Openings M that are open forward and can communicate with a space sp formed inside are provided at the lower ends of the left and right ends of the backrest C, and the rear extensions 14 are inserted so as to be able to engage with the openings M.

[0088] As a result, it is possible to provide a chair in which the backrest C supported by the support A has a favorable appearance.

[0089] In other words, since the rear extension portion 14 is inserted so that it can engage with the opening M that is open to the front, it becomes easier to adopt a configuration in which the peripheral surfaces other than the underside of the rear extension portion 14 can be in close contact with the opening M, making it possible to make the appearance between the backrest C and the rear extension portion 14 preferable while suppressing excessive exposure of the rear end portion of the rear extension portion 14.

[0090] A first back panel connecting portion 15 extending upward is provided at the rear end of the rear extension portion 14. A first fitting recess s2 is formed in the backrest C, which constitutes a space sp formed at the lower end and into which the first back panel connecting portion 15 is fitted.

[0091] Therefore, by fitting the first back panel connection portion 15 into the first mating recess s2, a configuration can be realized in which the backrest C is suitably supported by the leg component 1 without the first back panel connection portion 15 being exposed to the outside.

[0092] A second back panel connecting portion 16 protruding inward is provided at the rear end of the rear extension portion 14. A second fitting recess s3 is formed in the backrest C, which defines a space sp and into which the second back panel connecting portion 16 is fitted.

[0093] Therefore, by fitting the second back panel connection portion 16 into the second mating recess s3, a configuration can be realized in which the backrest C is suitably supported by the leg component 1 without the second back panel connection portion 16 being exposed to the outside.

[0094] A screw insertion hole h4 penetrating in the vertical direction is provided in the second back panel connection portion 16, and the backrest C is attached to the support body A by screwing a screw v4 inserted into the screw insertion hole h4 into a nut portion n4 facing the second mating recess s3.

[0095] This allows the backrest C to be appropriately fixed to the support A using the screw v4.

[0096] The space sp is surrounded by a front wall c1 that can form the front surface of the backrest C, a side wall c2 that can form the side surface of the backrest C, and a rear wall c3 that can form the back surface of the backrest C. The opening edge of the opening M includes the front edge of the side wall c2.

[0097] As a result, the outer surface side of the rear end of the rear extension portion 14 is also covered by the side wall c2, making it difficult for the rear end of the rear extension portion 14 to be exposed, resulting in a preferable appearance.

[0098] The lower end portion ce of the backrest C in the left-right direction middle portion is located below the seating surface zm of the seat B.

[0099] Therefore, the backrest C can suitably support not only the user's lower back but also his / her buttocks from behind.

[0100] It should be noted that the present invention is not limited to the embodiment described above in detail.

[0101] The rear extensions are not limited to those extending rearward from the left and right front legs, but may be those extending rearward from the left and right rear legs.

[0102] The rear extension portion is not limited to being inserted from below toward above into the opening as shown in the above-described embodiment, but may be inserted from the front toward the rear into the opening.

[0103] The first and second back panel connecting portions do not have to be provided integrally with the rear end portion of the rear extension portion, and may be formed separately.

[0104] The rear extension portion may be provided with only either the first back plate connecting portion or the second back plate connecting portion.

[0105] The space formed inside the backrest need only be capable of suitably accommodating a member that can be connected to the backrest and is provided on the support body, and the specific shape of the space can be set in various ways.

[0106] In the above-described embodiment, the rear wall that can form the back surface of the backrest is configured so as not to have a screw insertion hole. However, for example, it is also possible to provide a screw insertion hole in the rear wall, and to fix the support body and the backrest by inserting a screw through the screw insertion hole and screwing it into the rear extension portion.

[0107] The lower end of the backrest in the left-right direction middle portion may be located above the seat surface.

[0108] Furthermore, the specific configuration of each part is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0109] A...Support C…Backrest M…Opening 11. Hind legs 12...front legs 14...Rear extension part

Claims

1. A chair having a backrest supported by a support, the support body includes front legs arranged in a pair on the left and right, rear legs arranged in a pair on the left and right, and rear extension parts extending rearward from the left and right rear legs or the left and right front legs, The backrest has a lower end provided with an opening that is open forward and communicates with a space formed inside, and the rear extension is inserted into the opening so as to engage with the opening. A second back panel connection portion is provided at the rear end of the rear extension portion and protrudes inward, and a second fitting recess is formed in the backrest which defines the space and into which the second back panel connection portion is fitted.

2. A chair having a backrest and a seat supported by a support, the support body includes front legs arranged in a pair on the left and right, rear legs arranged in a pair on the left and right, and rear extension parts extending rearward from the left and right rear legs or the left and right front legs, The backrest has a lower end provided with an opening that is open forward and communicates with a space formed inside, and the rear extension is inserted into the opening so as to engage with the opening. The rear extension portion is disposed outwardly of a seat body having a seating surface of the seat in a plan view, The seat is connected to the rear extension portion via a shaft member so as to be rotatable between a use position in which a seat occupant can sit and a standing position in which the seat occupant stands on a floor surface, The seat is configured to be stackable in the front-rear direction on a floor surface with other chairs having the same structure when the seat is in the upright position, A first back panel connection portion extending upward is provided at the rear end of the rear extension portion, and a first fitting recess that defines the space and into which the first back panel connection portion is fitted is formed in the backrest.

3. A chair as described in claim 1, wherein a screw insertion hole penetrating in the vertical direction is provided in the second back panel connection portion, and the backrest is attached to the support by screwing a screw inserted into this screw insertion hole into a nut portion facing the second fitting recess.

4. The space is surrounded by a front wall that can form the front surface of the backrest, a side wall that can form the side surface of the backrest, and a rear wall that can form the back surface of the backrest, 4. The chair according to claim 1, 2 or 3, wherein the opening edge of the opening includes the front end edge of the side wall.

5. 5. The chair according to claim 1, 2, 3 or 4, wherein a lower end of the backrest in the left-right middle portion is positioned below a seating surface of the seat.

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