Chair structure and chair

Abstract

To enable stable external appearance to improve appearance.SOLUTION: In a chair seat 20, a cushion 22 is stacked on an inner shell 23 in a stacking direction and covered with a face fabric 21 and a peripheral edge of the face fabric 21 is wound around to the rear side of the inner shell 23, where the inner shell 23 includes an extension part 27 having a flange shape projecting from a side to the outside. The cushion 22 is provided such that a peripheral edge portion 22a faces the extension part 27 in the stacking direction.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a chair structure such as a seat and a backrest, and a chair. More specifically, the present invention relates to a chair structure and a chair that are useful when applied to a structure in which a cushioning material is sandwiched between an inner shell and a covering material and covers the sides of the inner shell. [Background technology]

[0002] Conventionally, in chair structures such as seats and backrests, cushioning materials made of urethane or the like are placed on a rigid inner shell, the cushioning materials and the inner shell are wrapped in a skin material, and the periphery of the skin material is tightened on the back side of the inner shell with a string member. In recent years, for example, a structure is known in which a flat cushioning material is superimposed on a flat inner shell, and the skin material covering the cushioning material is fastened to the side part of the inner shell (Patent Document 1). Alternatively, for example, a structure is known in which the cushioning material is wrapped around from the side to the back side of the inner shell, and the periphery of the skin material wrapping the cushioning material is fastened to the back side of the inner shell (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-344399 A [Patent Document 2] JP 2009-172275 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the invention described in Patent Document 1, since the inner shell and the cushioning material are flat, it is difficult to position the cushioning material in an appropriate position when the cushioning material is placed on the top of the inner shell. This makes it difficult to work with the skin material when fastening it. In addition, if the position of the cushioning material is shifted relative to the inner shell, the skin material may hit the top surface of the inner shell without the cushioning material, which may result in a poor appearance.

[0005] In the invention described in Patent Document 2, the cushioning material is made to wrap around the back surface of the inner shell, so it is possible to prevent the cushioning material from shifting from the inner shell, but due to the physical properties of the soft cushioning material, the part that comes into contact with the side surface of the inner shell is unlikely to be flat, and the periphery of the seat is likely to have an uneven shape, which may result in a poor appearance of the seat. Also, since the shape of the side surface of the seat depends on how the cushioning material is crushed, wrinkles are likely to occur in the covering material, making it difficult to form a seat with a stable appearance.

[0006] An object of the present invention is to provide a chair structure and a chair that can achieve a stable appearance and improve the appearance. Furthermore, the object is to provide a chair structure for a flip-up seat that has flat sides to suppress interference with the leg frame when the seat is rotated, while appropriately reducing the gap between the seat and the leg frame. [Means for solving the problem]

[0007] In order to achieve this object, the chair structure of the present invention is a chair structure in which a cushioning material is overlapped on an inner shell in an overlapping direction and covered with a skin material, and the peripheral edge of the skin material is wrapped around the back side of the inner shell, the inner shell has a flange-shaped extension portion that protrudes outward from a side portion, and the cushioning material is provided such that the peripheral edge portion faces the extension portion in the overlapping direction. The chair includes leg frames arranged to sandwich the structure from the width direction of the chair, and a rotating member that supports the structure rotatably around a horizontal axis in the width direction relative to the leg frames, the structure being a chair seat that can be switched between a horizontal position and a vertical position relative to the leg frames, and the extension portion is provided on at least the side portion in the width direction of the seat. I try to do so.

[0008] In the chair structure of the present invention, it is preferable that the peripheral edge of the cushioning material abuts against at least a part of the extension.

[0009] The chair structure of the present invention The periphery of the cushioning material is At the portion where the extension abuts, The thickness corresponds to the amount of protrusion of the extension portion, Outer surface of cushioning material and the outer surface of the extension Located on the same plane The outer peripheral surface of the side of the seat facing the leg frame is shaped flat. It is preferred.

[0010] The chair structure of the present invention In The extension is on the side of the seat in the width direction. and rear It is provided in It is preferred.

[0011] Here, it is preferable that the extension portion is not provided in the vicinity of the rotating member.

[0012] It is also preferable that an outer shell be provided which supports the inner shell from below, and that the periphery of the skin material be fastened to the inner shell and covered by the outer shell.

[0013] Furthermore, the inner shell is preferably a resin molded product.

[0014] The chair of the present invention is provided with a structure according to any one of claims 1 to 7. Effect of the Invention

[0015] According to the chair structure of the present invention, the inner shell has a flange-shaped extension, and the cushion material has a peripheral portion facing the extension in the stacking direction, so that the peripheral portion of the cushion material does not wrap around to the back side of the inner shell beyond the extension. Therefore, the cushion material is less likely to be crushed compared to when the cushion material wraps around to the back side of the inner shell. This makes it easier to make the peripheral portion of the cushion material flat by utilizing the outer peripheral surface of the extension, improving the appearance of the structure. In addition, in a flip-up seat, the sides of the seat are flat, so interference with the leg frame when the seat rotates is suppressed compared to when the sides of the seat are uneven, and the gap between the seat and the leg frame can be appropriately reduced. Therefore, there is no need to create a gap between the seat and the leg frame that is larger than necessary, and the chair can be made smaller while still maintaining the seat area.

[0016] In addition, by providing the peripheral portion of the cushioning material opposite the extending portion, even if the cushioning material is pressed from the outside to the inside by the skin material, the extending portion acts as a guard to prevent the cushioning material from losing its shape and to prevent the cushioning material from being partially recessed below the extending portion. This prevents the cushioning material from being crushed and wrinkles from occurring in the skin material, improving the stability of the external appearance of the structure. Moreover, since the peripheral portion of the cushioning material can be foamed to a thickness equivalent to the amount of overhang of the extending portion up to the edge portion, the edge shape can be formed into a sharp shape without unevenness.

[0017] According to the invention described in claim 2, the peripheral edge abuts at least a portion of the extension, thereby reducing the gap between the extension and the peripheral edge of the cushioning material and reducing the space in which the skin material can wrinkle, making it more difficult for wrinkles to occur in the skin material.

[0018] According to the invention described in claim 3, since the outer surface of the cushioning material is located on the same plane as the outer surface of the extension, it is possible to easily make the outer circumferential surface of the structure into a flatter shape.

[0020] According to the invention described in claim 5, since the extension is not provided near the rotating member, the amount of overhang in the width direction near the rotating member of the seat is smaller than other parts. Therefore, when the seat rotates, friction between the seat and the leg frame near the rotating member can be reduced, and the force required to lift the seat can be reduced, improving operability.

[0021] According to the invention described in claim 6, since the peripheral edge of the skin material is fastened to the inner shell and covered by the outer shell, the peripheral edge of the skin material fastened to the inner shell can be hidden, thereby improving the appearance of the structure.

[0022] According to the invention described in claim 7, since the inner shell is a resin molded product, it is possible to obtain an inner shell of any shape, improving design. Moreover, since the inner shell can be formed by injection molding, the cost of the parts can be reduced compared to when additional processing is performed.

[0023] Furthermore, according to the chair of the present invention, the peripheral edge of the cushioning material can be easily made flat by utilizing the outer circumferential surface of the extension, thereby improving the appearance of the structure. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view showing an embodiment in which the chair structure of the present invention is applied to a seat of a nesting chair. [Diagram 2] FIG. 2 is a perspective view showing the seat of the chair with the upholstery, cushion, and inner shell in a transparent state. [Diagram 3] FIG. 2 is a side view showing the chair with the seat flipped up to a storage position. [Figure 4] FIG. 2 is a perspective view of the chair as seen from the front with the seat flipped up to a storage position (the upholstery, cushion and inner shell are shown as transparent). [Diagram 5] FIG. 2 is a perspective view showing the relationship between the legs, seat, and backrest of the chair as viewed diagonally from below and behind. [Figure 6] 1 is a perspective view showing the front leg portion, the seat support portion, the rear leg portion, and the protrusions at the upper ends of the rear leg portions of the leg frame of the chair. FIG. [Figure 7] FIG. 2 is an exploded perspective view showing the seat frame, inner shell, cushion, and upholstery that constitute the seat of the chair. [Figure 8] 4 is an enlarged perspective view of a portion where a rotation support shaft member penetrates between an inner shell and a seat frame in a disassembled state. FIG. [Figure 9] FIG. 4 is an enlarged perspective view of a through-hole portion of the seat frame of the chair. [Figure 10] FIG. 2 is a plan view of the inner shell of the chair. [Figure 11] FIG. 2 is a bottom view of the inner shell of the chair. [Figure 12] 11 is a cross-sectional view showing the seat of the chair taken along line AA in FIG. 10. FIG. [Figure 13] 11 is a cross-sectional view showing the seat of the chair taken along line BB in FIG. 10. FIG. [Figure 14] FIG. 2 is an enlarged bottom view of the inner shell of the chair. [Figure 15] FIG. 2 is a perspective view of the inner shell as viewed from above. [Figure 16] FIG. 2 is an enlarged perspective view of the periphery of the edge of the inner shell as viewed from below. [Figure 17] FIG. 2 is a perspective view of the cushion seen from below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

[0026] 1 to 17 show an embodiment in which the chair structure of the present invention is applied to the seat of a nesting chair. In this specification, up / down, front / back, and left / right are defined based on a person sitting on the seat of the chair, and in particular, with respect to the seat when it is in a horizontal position. A seat in a horizontal position includes a state in which the seat surface is approximately horizontal as well as a state in which it is exactly horizontal, and a seat in a vertical position includes a state in which the seat surface is approximately vertical as well as a state in which it is exactly vertical.

[0027] The nesting chair in this embodiment is designed to be nested in the front-to-rear direction with other chairs of the same structure with the seat flipped up to a storage position, and has a rotating structure that supports the seat relative to the leg frame so that it can rotate between a position where it is maintained in an approximately horizontal position (seat use position) and a flipped up position where it is maintained in an approximately vertical position (seat storage position).

[0028] As shown in Figures 1 to 5, the nesting chair 1 of this embodiment has left and right leg frames 2 that form the legs, and a seat 20 and backrest 7 that are supported on each leg frame 2 so as to be freely rotatable around a horizontal axis in the width direction, and the seat 20 is switchable between a horizontal position and a vertical position.

[0029] In this embodiment, the legs are assembled by connecting the left and right leg frames 2 with each other using the seat 20, backrest 7, and left and right leg connecting pipes 8 attached therebetween (see Figs. 4 and 5). That is, the left and right leg frames 2 are arranged to sandwich the seat 20 in the width direction. Each leg frame 2 includes a front leg 3, a rear leg 5, a seat support part 4 that connects the front leg 3 and the rear leg 5 at their upper parts, and a horizontal connecting part 6, and is integrally molded by, for example, aluminum die casting. Molding the leg frame 2 by aluminum die casting increases the degree of freedom in shape, so that it is possible to provide a leg frame with excellent design by reducing restrictions on the design of the leg frame. In this embodiment, the leg frame 2 is made of aluminum die-cast, but is not limited to this, and may be a general leg frame made by bending a single metal pipe such as a stainless steel pipe or an aluminum alloy pipe and welding it to the same metal plate, or may be molded from a rigid resin having rigidity such as glass fiber reinforced nylon such as PA6-GF (polyamide 6). In any case, it goes without saying that the structure according to the present invention can be applied.

[0030] The horizontal connecting portion 6 is formed, for example, so as to protrude diagonally forward and inward from the inner surface of the front leg portion 3, and has a tip fitting portion 6a bent so as to face the opposing leg frame 2, into which the left and right leg connecting pipes 8 are fitted (see FIG. 6). The left and right leg connecting pipes 8 are fitted into the tip fitting portion 6a of the horizontal connecting portion 6 and screwed, so that the front sides of the left and right leg frames 2 are connected to each other via the left and right leg connecting pipes 8. In this embodiment, the left and right leg connecting pipes 8 are, for example, square pipes, and are fitted into the square shaft-shaped tip fitting portion 6a of the horizontal connecting portion 6. Although not shown, a core material for reinforcement is contained inside the left and right leg connecting pipes 8, and both ends of the core material are connected to the tip fitting portion 6a of the horizontal connecting portion 6 to increase the rigidity of the left and right leg connecting pipes 8, particularly the rigidity in the vertical direction, and prevent bending.

[0031] 3, the horizontal connector 6 and the left and right leg connecting pipes 8 are arranged in a position forward of the pivot support shaft member 11, which is an example of a pivot member fixed to the seat support part 4, so long as they can receive and support the horizontal rail portion 25 of the seat frame 24 forward of the pivot support shaft member 11, but at the same time, it is preferable to arrange them as close as possible to the pivot support shaft member 11 in order to increase nesting efficiency, since they remain between the left and right leg frames 2 when the seat 20 is flipped up to the storage position and put into a vertical position. Therefore, in the case of this embodiment, as shown in Figs. 2 and 5, for example, when the seat 20 is reclined to a horizontal position, the horizontal connector 6 and the left and right leg connecting pipes 8 are arranged to be arranged midway between the position where the pivot support shaft member 11 passes through and the tip edge of the seat frame 24.

[0032] 6, a screw hole 35 is provided at the middle position in the front-rear direction of the seat support part 4 to which the rotating support shaft member 11 is fixed, which protrudes in the left-right direction toward the opposing seat support part 4, i.e., toward the inside of the chair 1. Moreover, a boss part 36 is formed on the surface into which the rotating support shaft member 11 is screwed, and a countersunk hole 37 that serves as the entrance part of the screw hole 35 is provided.

[0033] As shown in FIG. 2, a rear damper 33 is provided on the inner surface of the rear leg 5 (the mutually facing surfaces of the rear leg 5 of the left and right leg frames 2). The rear damper 33 is, for example, a resin block, and is attached to the rear leg 5 by, for example, screws or adhesive. A front damper 34 is provided on the corner of the left and right connecting part 6 of the front leg 3. The front damper 34 is, for example, a resin block, and is attached to the corner of the left and right connecting part 6 by, for example, screws or adhesive. This prevents the rear leg 5 from coming into direct contact with the corner of the left and right connecting part 6 of the front leg 3 when the chair is nested in the front-rear direction with another chair of the same structure with the seat 20 flipped up, thereby reducing the sound generated during impact or collision.

[0034] Here, the leg frame 2 of this embodiment is formed so that the seat support part 4 and the front leg part 3 are gradually offset inward toward the tip side with respect to the rear leg part 5, and is configured so that the outer leg width (the outer distance between the left and right front legs 3) of the front leg part 2 is narrower than the inner leg width (the inner distance between the left and right rear legs 5) of the rear leg part 5 when the left and right leg frames 2 are assembled. As a result, when multiple chairs 1 are lined up in the front-rear direction, the left and right front legs 3, 3 of the other rear chair enter between the left and right rear legs 5, 5 of the front chair, resulting in a leg structure that allows nesting. In this embodiment, casters 38 are attached to the lower ends of the front legs 3 and the rear legs 5, respectively, but the provision of the casters 38 is not an essential configuration in the present invention.

[0035] The backrest 7 is a resin molded product in which the back frame 7a, the backrest surface 7b, and the cylindrical attachment parts (receptacles) 7c are integrally molded by injection molding at the lower end parts of both sides of the back frame 7a, and is formed in a shape in which the middle part in the left-right direction is curved backward in a plan view, and the part slightly below the center in the up-down direction is curved forward to be convex. And the backrest surface 7b has many small holes 7d penetrating in the front-rear direction.

[0036] 6, the backrest 7 is attached to the leg frame 2 by, for example, fitting the mounting portion 7c at the lower end of the back frame into the protruding portion 5a that tapers toward the top of the upper end of the rear leg 5. That is, the cylindrical mounting portion (receptacle) 7c of the backrest 7 and the protruding portion 5a at the upper end of the rear leg 5 form a spigot joint, and are fixed to each other in the fitted state, for example, by screwing.

[0037] As shown in Fig. 7, the seat 20 is composed of an upholstery 21, which is an example of a skin material that forms the seat surface, a cushion 22, which is an example of a cushion material that supports the upholstery 21, an inner shell 23 that supports the cushion 22, and a seat frame 24, which is an example of an outer shell that supports and reinforces the inner shell 23 from below, and is integrated by wrapping the cushion 22 placed on the inner shell 23 with the upholstery 21, sandwiching the periphery of the upholstery 21 between the seat frame 24 and the inner shell 23, and overlapping and screwing the seat frame 24 and the inner shell 23. The detailed structure of the seat 20 will be described later. In this embodiment, the mechanical strength of the seat 20 as a structure is mainly ensured by the seat frame 24.

[0038] Furthermore, an arch-shaped horizontal crosspiece 25 protruding toward the floor is provided at approximately the center of both the left and right sides of the seat frame 24. This horizontal crosspiece 25 is provided to abut against the left and right leg connecting pipes 8 fitted between the horizontal connecting parts 6 of the legs, thereby supporting the entire seat frame 24.

[0039] 5, a resilient buffer pad 26 is provided at a portion of the back surface of the horizontal rail 25 that crosses almost the center of the seat frame 24, where the buffer pad 26 abuts against the left and right leg connecting pipe 8. The buffer pad 26 has, for example, a plate-shaped abutment portion and a locking pin (not shown) that is press-fitted into a hole (not shown) provided in the horizontal rail 25, and is disposed, for example, one on each side of the horizontal rail 25. When the seat 20 is tilted to the use position, the buffer pad 26 abuts against the left and right leg connecting pipes 8 on the leg side, thereby preventing the generation of impact noise and providing a buffering effect, and keeping the seat 20 at a height that allows it to assume a horizontal position suitable for sitting. The seat 20 assumes a horizontal position when the horizontal rail 25 abuts against the left and right leg connecting pipes 8 of the legs, and the horizontal position is maintained.

[0040] 8 and 9, the seat frame 24 is provided with through holes 39 for mounting the rotating support shaft member 11 symmetrically on one axis in the width direction, for example, at a position closer to the rear than the middle position in the front-rear direction. As an example, as shown in FIG. 3, the through holes 39 are provided so that the rotating support shaft member 11 is disposed at a position closer to the rear end side than the center of the seat frame 24 and at a position where the center of gravity position G is set on the rear side (backrest 7 side) of the vertical line Lv passing through the rotating shaft portion 14 of the rotating support shaft member 11 when the seat frame 24 is flipped up to take a vertical position. As a result, when the seat 20 is flipped up around the rotating shaft portion 14 of the pivot structure to take a vertical position, the seat 20 is maintained in a vertical position by leaning against the backrest 7 or by frictional resistance applied by the frictional resistance applying member 15. 9, a countersunk hole 30 for receiving the head 13 of the rotating support shaft member 11 is provided at the entrance of the through hole 39, and a structure for preventing rotation of the friction resistance imparting member 15, such as a recess 31, is provided. The rotating support shaft member 11 is inserted into these through holes 39 and the screw 12 at the tip of the rotating support shaft member 11 is screwed into the screw hole 35 (see FIG. 6) of the seat support part 4, whereby the leg frame 2 and the seat frame 24 are rotatably connected.

[0041] The seat 20 and leg frame 2 of the nesting chair constructed as described above are rotatably connected on a single horizontal axis via a rotating structure and are attached to the leg frame 2 so as to rotate between a horizontal position (the position in which the seat 20 is used) and a vertical position (the storage position in which the seat 20 is raised up along the backrest 7).

[0042] Next, the structure of the seat 20 will be described in detail with reference to Figures 7 and 10 to 14. The seat 20 is formed by placing the cushion 22 on the inner shell 23 in the overlapping direction (up and down), covering it with the upper upholstery 21, fastening the periphery of the upper upholstery 21 around the back side of the inner shell 23, and assembling the seat frame 24 from the back side of the inner shell 23. As a result, the periphery 21a of the upper upholstery 21 is fastened to the inner shell 23 and is covered and hidden by the seat frame 24. Furthermore, the seat frame 24 and the inner shell 23 are overlapped and screwed together to integrate the seat 20 into a single structure.

[0043] As shown in FIG. 15, the inner shell 23 of this embodiment has a concave shape at the seating part side supporting the buttocks at the rear side compared to the thigh supporting part side supporting the thighs at the front side to facilitate the ischial sitting position. That is, the seating part of the seat forms a concave surface conforming to the shape of the buttocks so as to envelop the buttocks of the seated person, and the front of the seating part is raised to prevent the buttocks of the seated person from sliding forward. The front end of the seat hangs forward so as not to be hit by the thighs of the seated person. In addition, the peripheral part of the inner shell 23 is raised so as to envelop the buttocks and thighs. Therefore, when viewed from the side, the inner shell 23 has a compound curved shape in which the front end hangs down, the rear part rises slightly, sinks again toward the buttocks, and rises again at the rear end, i.e., a shape that forms a gentle, approximately S-shaped shape (hereinafter referred to as a spline shape). Similarly, the seat frame (outer shell) 24 that supports the inner shell 23 from below has the same frame shape in the front, rear, left and right directions as the edge portion of the inner shell 23. Therefore, when viewed from the side, the front end hangs down, the rear part rises slightly, then sinks again toward the buttocks, and rises again at the rear end, forming a compound curved shape, that is, a gentle, roughly S-shaped shape (hereinafter referred to as a spline shape) (see FIG. 2). They are layered neatly.

[0044] The inner shell 23 and the seat frame 24 are, for example, resin molded products having the necessary rigidity as components of the seat 20. In this way, by making the inner shell 23 and the seat frame 24 resin molded products, they can be formed into any shape such as a spline shape while maintaining rigidity, improving the design. Moreover, since the inner shell 23 and the seat frame 24 can be formed by injection molding, the cost of parts can be reduced compared to when additional processing is performed. The inner shell 23 and the seat frame 24 have rib shapes that combine with each other at the joint. Also, in FIG. 8, a U-shaped groove 23a surrounding the boss portion 32 of the through hole 39 is formed on the periphery of the inner shell 23 that overlaps with the portion of the seat frame 24 through which the rotation support shaft member 11 penetrates, and they are overlapped without any gaps.

[0045] In this embodiment, as shown in Fig. 10, Fig. 12 to Fig. 15 and Fig. 16, the inner shell 23 has a flange-shaped extension 27 protruding outward from the side. The extension 27 is provided on the side and rear of the seat 20 in the width direction. As shown in Fig. 12, in this embodiment, the cushion 22 is provided with the peripheral edge 22a abutting against the extension 27 in the up-down direction. That is, in this embodiment, the peripheral edge 22a of the cushion 22 and the extension 27 are provided in contact with each other without any gaps over the entire area. Therefore, the peripheral edge 22a of the cushion 22 does not extend below the extension 27, and the cushion 22 is less likely to be crushed compared to the case where the cushion 22 is extended around the back side of the inner shell 23. As a result, the peripheral edge 22a of the cushion 22 can be easily made flat by utilizing the outer peripheral surface 27a of the extension 27, and the appearance of the seat 20 can be improved (see Fig. 17). In addition, at the portion where the cushion 22 abuts against the extension 27, the outer surface 22b of the cushion 22 is located on the same plane, i.e., flush with the outer surface 27a of the extension 27. This makes it easy to shape the outer circumferential surface of the seat 20 into a flat shape.

[0046] Furthermore, even if the peripheral edge 22a of the cushion 22 abuts against the extension 27 and is pressed inward from the outside by the upholstery 21, the extension 27 acts as a guard to prevent the cushion 22 from losing its shape and to prevent the cushion 22 from partially sinking below the extension 27. This prevents the cushion material from being crushed and wrinkles from forming in the covering material, and the sharp shape of the extension 27 can be utilized to improve the stability of the appearance of the seat 20.

[0047] Here, when the extension 27 is not provided on the inner shell 23, the peripheral edge of the cushion 22 is formed long downward, for example, so that it wraps around the back side of the inner shell 23. In this case, when forming the cushion 22 from foamed urethane, if the peripheral edge is gradually thinned to be long so as to eliminate the step, the tip of the edge will not have a uniform length or thickness but will be wavy, which makes it easy to generate unevenness when wrapped with the upholstery 21. In contrast, in this embodiment, the cushion 22 can be foamed with a thickness equivalent to the amount of overhang of the extension 27 up to the edge part, as shown in FIG. 12, so that the edge shape can be formed into a sharp shape without unevenness. In other words, the peripheral edge 22a can be formed to a uniform length and thickness up to the extension 27. Therefore, the outer peripheral surface of the seat 20 can be easily made flat.

[0048] By making the outer peripheral surface of the side of the seat 20 flat, interference with the leg frame 2 during rotation of the seat 20 is suppressed even if the clearance to the leg frame 2 is set narrower, compared to when the side of the seat 20 is uneven, and the gap between the seat 20 and the leg frame 2 can be appropriately reduced. Therefore, there is no need to form an unnecessarily large margin, and the chair 1 can be made smaller while still ensuring the area of ​​the seat 20.

[0049] In this embodiment, the peripheral portion 22a of the cushion 22 and the extending portion 27 are in contact with each other without any gaps over the entire area, but the present invention is not limited to this. For example, the peripheral portion 22a of the cushion 22 and the extending portion 27 may not be in contact with each other without any gaps over the entire area, and may have a gap between them. Alternatively, the peripheral portion 22a of the cushion 22 and the extending portion 27 may be provided with a gap over the entire area. That is, the peripheral portion 22a of the cushion 22 may be provided facing the extending portion 27 in the up-down direction. By configuring the cushion in this way, as described above, the peripheral portion 22a of the cushion 22 can be easily made into a flat shape by utilizing the outer peripheral surface 27a of the extending portion 27, and the extending portion 27 acts as a guard to prevent the cushion 22 from losing its shape even when the cushion 22 is pressed from the outside to the inside by the upholstery 21, thereby improving the appearance of the seat 20.

[0050] In this embodiment, the extensions 27 are provided on the sides and rear of the seat 20 in the width direction, but are not provided on the front of the seat 20 or on the sides in the vicinity of the pivot support shaft member 11. Since there is no restriction on the thickness of the cushion 22 in the front of the seat 20, the shape of the seat 20 can be maintained by forming the cushion 22 sufficiently thick. In addition, if the extensions 27 are provided in the front of the seat 20, they may hit the back of the knees of a seated user, which may impair the comfort of sitting, so the extensions 27 are not provided. In addition, in the vicinity of the pivot support shaft member 11, friction may occur between the seat 20 and the leg frame 2 when the seat 20 rotates, so the extensions 27 are not provided to ensure a gap between the seat 20 and the leg frame 2. As a result, friction between the seat 20 and the leg frame 2 can be reduced when the seat 20 rotates, and the force required to lift the seat 20 can be reduced, improving operability. However, the extension 27 does not necessarily have to be provided near the rotation support shaft member 11, and may be provided therein.

[0051] Next, the fastening structure of the periphery of the upper upholstery 21 will be described in detail with reference to Figs. 10 to 17. As shown in Figs. 12 to 14, the periphery 21a of the upper upholstery 21 is provided with locking members 28 on both sides and locking members 29 on the front and rear ends. The locking members 28, 29 can be, for example, a flat polypropylene cord (commonly called a PP cord) with a rectangular cross section and a thickness of about 1 mm. This flat PP cord with a rectangular cross section is relatively hard in the width direction (longitudinal direction) and flexible in the thickness direction (transverse direction). However, the locking members 28, 29 are not limited to the PP cord described above. Here, the edges of the front and rear ends of the inner shell 23 in the seat of this embodiment are linear and almost parallel to the horizontal plane, and curved in the front-rear direction in the width direction, so that the locking member does not require flexibility along the bottom surface of the groove 23f of the inner shell 23, but does require flexibility along the side surface of the groove 23f. Therefore, the locking member 29 is arranged and sewn along the periphery of the back surface of the upper upholstery 21, and the upper upholstery 21 is folded back to wrap around the locking member 29, and then placed vertically in the groove 23f of the inner shell 23 (i.e., the width direction in which the PP cord shows rigidity is the insertion direction into the groove). On the other hand, both sides of the inner shell 23 in the seat of this embodiment are shaped like a sprung curve that is gently S-shaped with respect to the horizontal plane, so that the edges of the inner shell are almost linear in the front-rear direction, but require flexibility along the bottom surface of the groove 23c of the inner shell 23, but does not require flexibility along the side surface of the groove 23c. Therefore, the locking member 28 is placed horizontally in the groove 23c (i.e., the thickness direction is the insertion direction into the groove so that the surface of the PP cord faces the bottom of the groove 23c). In this embodiment, the locking member 28 is fastened to the upper upholstery 21, for example, by being placed in a storage bag 21b sewn to the periphery 21a of the upper upholstery 21. However, the configuration for fastening the locking members 28, 29 to the upper upholstery 21 is not limited to being inserted into the storage bag 21b, and for example, the locking members 28, 29 may be sewn directly to the periphery 21a of the upper upholstery 21. In this specification, the surface of the flat locking members 28, 29 refers to the surface perpendicular to the thickness direction of the locking members 28, 29.

[0052] As shown in Figs. 11 to 14 and 16, a pair of ribs 23b projecting downward along the outer periphery are provided at both sides at a fixed interval on the periphery of the back surface of the inner shell 23, and a pair of ribs 23e are also provided at the front end and the rear end at a fixed interval. A groove 23c is formed between the pair of ribs 23b, and a groove 23f is formed between the ribs 23e. The pair of ribs 23b and the groove 23c in the seat 20 of this embodiment, in other words, the inner shell 23, are formed along the edges of both sides of the inner shell 23. Therefore, the pair of ribs 23b and the groove 23c are formed substantially linearly in the front-rear direction (i.e., extending substantially linearly in the front-rear direction when viewed from the bottom). Furthermore, the bottom surface of the groove 23c (i.e., the back surface of the inner shell 23) forms a sprung shape that is curved in an S-shape that is gently undulating with respect to the horizontal plane. In this embodiment, in addition to the four ribs 23b, 23e, the inner shell 23 has another rib to ensure the rigidity of the inner shell 23. The grooves 23c, 23f house the locking members 28, 29 of the upper upholstery 21. It is preferable that the width of the groove 23c is at least slightly wider than the sum of the width of the PP cord and the thickness of the storage bag 21b, and the width of the groove 23f is at least slightly wider than the sum of the thickness of the PP cord and the thickness of the upper upholstery 21.

[0053] In this embodiment, the grooves 23c provided on both sides of the inner shell 23 in the width direction are arranged so that the surface of the locking member 28 faces the bottom surface of the grooves 23c, and the locking member 28 is accommodated in the grooves 23c along the spline shape of the inner shell 23 to provide flexibility. That is, the locking member 28 is placed horizontally in the grooves 23c, so that the locking member 28 is allowed to provide flexibility that conforms to the shape of the inner shell 23. In this embodiment, the width of the grooves 23c needs to be set at least equal to or slightly wider than the width of the locking member 28, but is preferably slightly wider than the width of the PP cord and the thickness of the storage bag 21b. As a result, the locking member 28 accommodated in the bottom of the grooves 23c is stably held by the ribs 23b from both sides in the width direction. On the other hand, the width of groove 23f needs to be set at least wider than the thickness of the PP cord plus the thickness of the upper upholstery 21, but it is preferable that the width be such that the locking member 28 and the upper upholstery 21 can be inserted without any hindrance and will not come loose.

[0054] As shown in Figures 12 and 13, the upper upholstery 21 wraps around from the front surface of the seat 20, past the extension 27, along the back side of the inner shell 23 in an approximately horizontal direction, with the periphery 21a passing over the rib 23b and entering upward toward the bottom of the groove 23c. That is, the groove 23c is bent at an angle of approximately 90° to the direction in which the tension of the upper upholstery 21 acts, so that it is not on the same line, and the direction in which the tension is applied is changed. Therefore, the tension generated in the upper upholstery 21 acts horizontally from below the extension 27, but the upper upholstery 21 is prevented from easily coming loose because the direction in which the tension acts is bent downward by the rib 23b.

[0055] As shown in Figs. 13 and 14, the groove 23c into which the horizontally placed locking member 28 is inserted has a locking portion 23d. The locking portion 23d is, for example, a claw facing the bottom side of the groove 23c (upward in Fig. 13), and when the locking member 28 is inserted into the groove 23c, it deforms in a direction to widen the groove width, while when the locking member 28 housed in the groove is pulled and tries to come out of the groove 23c, it locks with the locking member 28 to prevent it from coming out. This makes it possible to prevent the horizontally placed locking member 28 from coming out of the groove 23c when the upholstery 21 is pulled. In this embodiment, the locking portions 23d are formed in pairs facing each other in the width direction, protruding inward from each of the pair of ribs 23b toward the bottom side of the groove 23c and inclined so as to lock onto both sides in the width direction of the locking member 28. As a result, when the locking member 28 is provided in the groove portion 23c, it is provided at the bottom by passing between the locking portions 23d, and when the locking member 28 provided in the groove portion 23c is pulled and tries to come out, both sides in the width direction are caught by the locking portions 23d to prevent it from coming out. Therefore, it is desirable that the distance between the pair of locking portions 23d is shorter than the length of the locking member 28 in the width direction. The shape of the locking portion 23d is not limited to a claw shape, and may be a convex portion or the like as long as it can prevent the locking member 28 from coming out of the groove portion 23c. In addition, in this embodiment, since the inner shell 23 is a resin molded product, the groove portion 23c and the locking portion 23d can be integrally formed when the inner shell 23 is formed.

[0056] 10, 11 and 16, in this embodiment, the locking portions 23d are arranged at, for example, five locations at substantially equal intervals from one groove portion 23c, and are provided so as to be evenly fastened to the inner shell 23 over the entire area of ​​the locking member 28 arranged on the side of the chair 20, but this is not particularly limited, and the number of locking portions 23d may be changed as appropriate. Also, in this embodiment, the pair of locking portions 23d are arranged opposite each other between the left and right ribs 23b, but this is not particularly limited, and the locking portions 23d may be arranged offset in the longitudinal direction of the groove.

[0057] On the other hand, as shown in Figs. 12 and 13, the seat frame 24 is formed with a pier-shaped retaining portion 24a that fits into the groove 23c at a position facing the groove 23c of the inner shell 23. The retaining portion 24a is not constantly pressed against the locking member 28 housed in the groove 23c, but is disposed to face the groove with a clearance. In other words, the peripheral portion of the upper upholstery 21 is not fixed by the retaining portion 24a. The retaining portion 24a is configured to prevent the locking member 28 from coming out of the groove 23c by contacting the retaining portion 24a. In other words, under normal circumstances when no external force is applied to the upper upholstery 21, the locking member 28 does not come into contact with the retaining portion 24a, but when an external force is applied to the upper upholstery 21 and a large tension is applied, the locking member 28 comes into contact with the retaining portion 24a and is prevented from coming out.

[0058] Furthermore, the seat frame 24 has ribs 24b adjacent to the ribs 23b of the inner shell 23. Therefore, as shown in Fig. 12, at the peripheral portion between the inner shell 23 and the seat frame 24, the ribs 23b of the inner shell 23 and the ribs 24b of the seat frame 24 are alternately adjacent to each other and arranged in a labyrinth shape.

[0059] Here, because the seat frame 24 has a thin frame shape, if an attempt is made to tighten the peripheral edge 21a of the upper upholstery 21 with a string member in this embodiment, it may not fit within the seat frame 24. In contrast, in this embodiment, the peripheral edge 21a of the upper upholstery 21 is fastened to the peripheral edges of the inner shell 23 and the seat frame 24, so that the peripheral edge 21a of the upper upholstery 21 can be contained within the seat frame 24, improving the appearance.

[0060] According to the seat 20 of the chair 1 configured as described above, the inner shell 23 has the flange-shaped extension 27, and the peripheral edge 22a of the cushion 22 abuts against the extension 27 in the vertical direction, so that the peripheral edge 22a does not wrap around to the back side of the inner shell 23 beyond the extension 27. Therefore, the cushion 22 is less likely to be crushed compared to when the cushion 22 wraps around to the back side of the inner shell 23. This makes it easier to make the peripheral edge 22a of the cushion 22 flat by utilizing the outer circumferential surface 27a of the extension 27, and the appearance of the seat 20 can be improved.

[0061] Furthermore, even if the peripheral edge 22a of the cushion 22 abuts against the extension 27 and is pressed inward from the outside by the upholstery 21, the extension 27 acts as a guard to prevent the cushion 22 from losing its shape and to prevent the cushion 22 from partially sinking in below the extension 27. This prevents the cushion 22 from being crushed and makes it less likely for wrinkles to form in the upholstery 21, improving the stability of the appearance of the seat 20.

[0062] Although the above-mentioned embodiment is one example of a preferred form for carrying out the present invention, the embodiment of the present invention is not limited to the above, and the present invention can be modified in various ways without departing from the scope of the present invention. For example, in the above-mentioned embodiment, an example is given in which the structure according to the present invention is applied to the seat 20 of the nesting chair 1, but the present invention is not particularly limited to this, and can be appropriately selected for the seats of other types of chairs. For example, a groove for receiving the periphery of the upholstery 21 may be provided in a single seat board (not separated into an inner shell and a seat frame), and the periphery of the upholstery 21 may be fastened to the structure.

[0063] In the above embodiment, a resin molded product is used as the inner shell 23, but the present invention is not limited thereto, and a material that is already used as an inner shell, such as plywood, may be used. For example, in the case of plywood, the extension portion can be formed by additional processing after the plywood is formed. In the case of a plywood inner shell, although not shown, the grooves 23c and 23f may be formed by groove processing, or the grooves 23c and 23f and the locking portion 23d may be provided by using rails (corresponding to ribs 23b and 23e) made of a separate material such as a steel plate.

[0064] In addition, the locking member 28 is not limited to a flat part having a rectangular cross section, and may have a polygonal cross section such as an ellipse, a cylinder, a square, or a triangle, as long as it has flexibility to follow the shape of the inner shell 23 and is capable of being prevented from coming off by being locked to the locking portion 23d. For example, when a locking member having a triangular cross section is used, the locking member 28 can be easily pushed into the groove 23c by inserting the ridge portion toward the bottom of the groove, and thereafter, the locking member 28 can be prevented from coming off by being caught by the locking portion 23d. In addition, even when a flexible material such as a wire is used as the locking member 28, there is no particular problem as long as the width of the groove 23c and the distance between the paired locking portions 23d are set and controlled to a dimension such that the locking member 28 can be inserted and not pulled out.

[0065] In the above embodiment, the seat of a chair is taken as an example, but the chair structure is not limited to that in the above embodiment. Specifically, the present invention can be applied to a backrest, a headrest, an armrest, etc. [Explanation of symbols]

[0066] 1 Chair 2 Leg Frame 11 Rotating support shaft member (rotating member) 20 seats (structures) 21 Upper covering material (skin material) 21a Edge (edge ​​of skin material) 22 Cushion (cushioning material) 22b Outer surface of cushioning material 23 Inner Shell 24 Seat frame (outer shell) 27 Extension 27a Outer surface of extension

Claims

1. A chair structure in which a cushioning material is overlapped on an inner shell in an overlapping direction and covered with a skin material, and the peripheral edge of the skin material is wrapped around the back side of the inner shell, The inner shell has a flange-shaped extension protruding outward from a side portion, The cushioning material is provided such that a peripheral portion faces the extending portion in the overlapping direction, the chair includes leg frames arranged to sandwich the structure in a width direction of the chair, and a rotating member that supports the structure rotatably about a horizontal axis in the width direction relative to the leg frames, the structure is a seat of the chair, and is switchable between a horizontal position and a vertical position with respect to the leg frame; The extension portion is provided on at least one side of the seat in the width direction. A chair structure characterized in that

2. 2. The chair structure according to claim 1, wherein the peripheral edge of the cushioning material abuts against at least a part of the extension.

3. A chair structure as described in claim 1 or 2, characterized in that the peripheral portion of the cushion material has a thickness equivalent to the amount of protrusion of the extension portion at the portion where it abuts against the extension portion, the outer surface of the cushion material and the outer surface of the extension portion are located on the same plane, and the outer peripheral surface of the side of the seat facing the leg frame is shaped flat.

4. A chair structure described in any one of claims 1 to 3, characterized in that the extension portions are provided on the sides and rear of the seat in the width direction.

5. 5. The chair structure according to claim 1, wherein the extension is not provided in the vicinity of the rotating member.

6. an outer shell supporting the inner shell from below on the inner side of the extension portion; A chair structure as described in any one of claims 1 to 5, characterized in that the peripheral edge of the cover material wraps around the extended portion of the inner shell and is fastened to the back side of the inner shell, the bottom side of the inner shell is covered by the outer shell, and the side of the cushion material, including the extended portion of the inner shell covered by the cover material, is exposed to the exterior.

7. 7. The chair structure according to claim 1, wherein the inner shell is a resin molded product.

8. A chair, characterized in that it comprises a structure according to any one of claims 1 to 7.

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