JP7565134B2 - Chair structure and chair - Google Patents

Description

The present invention relates to a chair structure, such as a seat and backrest, and to 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 covering material is fastened around the back side of an inner shell.

Conventionally, in chair structures such as seats and backrests, a cushioning material such as urethane is placed on a rigid inner shell, the cushioning material and 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 (Patent Document 1). In this structure, the inner shell is generally flat, and when the periphery of the skin material is tightened with the string member, it is in a generally flat state along the inner shell, so that the force can be distributed evenly to each part of the periphery of the skin material.

Japanese Patent Application Publication No. 10-71057

However, in the invention described in Patent Document 1, when the inner shell has a compound curved shape, such as a curved contour that forms a gentle, roughly S-shape when viewed from the side, even if the peripheral edge of the skin material is tightened with a string member, the peripheral edge does not become flat, making it difficult to distribute the force evenly to each part of the peripheral edge of the skin material. As a result, the tension of the peripheral edge of the skin material varies depending on the position, which may cause the skin material to lift up or wrinkle, or may make the skin material more likely to come off the inner shell.

The present invention aims to provide a chair structure and chair that can apply uniform tension to the covering material even if the inner shell has a complex curved shape.

In order to achieve this object, the chair structure of the present invention has a cushioning material layered on an inner shell and covered with a skin material, the peripheral edge of the skin material is wrapped around the back side of the inner shell, a locking member provided on the peripheral edge of the skin material is fastened to the back side of the inner shell , and the inner shell is supported from below by an outer shell , in which the inner shell has a groove portion on the back side for accommodating the locking member, and a locking portion that engages with the locking member when the locking member accommodated in the groove attempts to come out of the groove, thereby preventing the locking member from coming out, the locking member is flat and flexible so as to fit along the back surface of the inner shell which is the bottom of the groove of the inner shell, and is accommodated in the groove with its surface aligned along the bottom surface of the groove of the inner shell, and the outer shell is positioned opposite the locking member accommodated in the groove with a clearance, and has a slip-out prevention portion that abuts against the locking member when the locking member accommodated in the groove attempts to come out of the groove, thereby preventing the locking member from coming out .

In the chair structure of the present invention, it is preferable that the locking member is housed in a storage bag provided on the periphery of the covering material.

Furthermore , in the chair structure of the present invention, it is preferable that the structure is a chair seat, and that the groove portion for accommodating the locking member is formed so as to extend in the front-to-rear direction along both the left and right edges of the back surface of the inner shell of the seat.

The chair of the present invention is provided with a structure according to any one of claims 1 to 3 .

According to the chair structure of the present invention, the locking members provided on the periphery of the covering material have flexibility to conform to the bottom surface of the groove of the inner shell, and are housed in the groove along the shape of the inner shell. Therefore, even if the shape of the inner shell has a complex curved shape, the locking members can conform to the shape of the inner shell, allowing the covering material to be attached with uniform tension. This prevents the covering material from lifting up or wrinkling, and also makes it possible to firmly fasten the covering material to the inner shell. In addition, because the locking members are provided in the grooves, it is possible to prevent the locking members from coming loose when the covering material is pulled.

Furthermore, the outer shell is provided with a retaining portion that prevents the fastening member from slipping out , so that the fastening member can be prevented from slipping out when the covering material is pulled.

In addition, the flat locking member is accommodated in the groove with its surface aligned along the bottom surface of the groove in the inner shell, which improves the ability of the locking member to conform to the shape of the inner shell and allows the skin material to be attached with more uniform tension.

According to the second aspect of the present invention, the fastening member and the skin material can be prevented from being separated, and the skin material can be firmly fastened.

Furthermore, with the chair of the present invention, the covering material can be attached with uniform tension, which prevents the covering material from lifting up or wrinkling, and also makes it possible to firmly fasten the covering material to the inner shell.

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. FIG. 2 is a perspective view showing the seat of the chair with the upholstery, cushion, and inner shell in a transparent state. FIG. 2 is a side view showing the chair with the seat flipped up to a storage position. FIG. 2 is a front perspective view of the chair with the seat flipped up to a storage position (upholstery, cushion and inner shell are shown as transparent). 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. 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. FIG. 2 is an exploded perspective view showing the seat frame, inner shell, cushion, and upholstery that constitute the seat of the chair. 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. FIG. 4 is an enlarged perspective view of a through-hole portion of the seat frame of the chair. FIG. 2 is a plan view of the inner shell of the chair. FIG. 2 is a bottom view of the inner shell of the chair. 11 is a cross-sectional view showing the seat of the chair taken along line AA in FIG. 10. 11 is a cross-sectional view showing the seat of the chair taken along line BB in FIG. 10. FIG. 2 is an enlarged bottom view of the inner shell of the chair. FIG. 2 is a perspective view of the inner shell as viewed from above. FIG. 2 is an enlarged perspective view of the periphery of the edge of the inner shell as viewed from below. FIG. 2 is a perspective view of the cushion seen from below.

The configuration of the present invention will be described in detail below based on an example of an embodiment shown in the drawings.

Figures 1 to 17 show an embodiment of the present invention, with an example of applying the chair structure to the seat of a nesting chair. In this specification, up and down, front and back, and left and right are defined with reference to a person sitting on the chair seat, and with reference to the seat being in a horizontal position in particular. 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.

The nesting chair in this embodiment is designed to be nested in the front-to-rear direction with other chairs of the same structure when the seat is flipped up to a storage position, and has a rotational structure that supports the seat with respect to the leg frame so that it can rotate between a position where it is kept in a nearly horizontal position (seat use position) and a position where it is flipped up and kept in a nearly vertical position (seat storage position).

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, a seat 20 that is supported on each leg frame 2 so as to be rotatable around a horizontal axis in the width direction, and a backrest 7, and the seat 20 can be switched between a horizontal position and a vertical position.

In this embodiment, the legs are assembled by connecting the left and right leg frames 2 to each other using the seat 20, backrest 7, and left and right leg connecting pipes 8 attached between them (see Figures 4 and 5). That is, the left and right leg frames 2 are arranged to sandwich the seat 20 from 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, for example, by aluminum die casting. Molding the leg frame 2 by aluminum die casting increases the degree of freedom in shape, so it is possible to reduce the constraints on the design of the leg frame and provide a leg frame with excellent design. In this embodiment, the leg frame 2 is made of die-cast aluminum, but is not limited to this. For example, a general leg frame may be used, in which a single metal pipe, such as a stainless steel pipe or an aluminum alloy pipe, is bent and welded together with a metal plate of the same type, or, in some cases, the leg frame may be molded from a rigid resin with rigidity, such as glass fiber reinforced nylon, such as PA6-GF (polyamide 6). In either case, it goes without saying that the structure according to the present invention can be applied.

The horizontal connecting portion 6 is formed, for example, so as to protrude diagonally forward from the inner surface of the front leg portion 3 toward the inside, and has a tip fitting portion 6a that is bent so as to face the opposing leg frame 2 and fits the left and right leg connecting pipes 8 (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 that fit 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, especially the vertical rigidity, and prevent bending.

As shown in FIG. 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 support the horizontal rail portion 25 of the seat frame 24 forward of the pivot support shaft member 11. However, since they remain between the left and right leg frames 2 when the seat 20 is flipped up to the storage position and placed in a vertical position, it is preferable to place them as close as possible to the pivot support shaft member 11 in order to increase nesting efficiency. Therefore, in the case of this embodiment, as shown in FIG. 2 and FIG. 5, for example, when the seat 20 is tilted down to a horizontal position, the horizontal connector 6 and the left and right leg connecting pipes 8 are arranged to be placed midway between the position where the pivot support shaft member 11 passes through and the tip edge of the seat frame 24.

As shown in FIG. 6, a screw hole 35 is provided at the middle position of the seat support 4 in the front-rear direction to which the pivot support shaft member 11 is fixed, which protrudes left and right toward the opposing seat support member 4, i.e., toward the inside of the chair 1. In addition, a boss portion 36 is formed on the surface into which the pivot support shaft member 11 is screwed, and a countersunk hole 37 is provided as the entrance portion of the screw hole 35.

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). This rear damper 33 is, for example, a resin block, and is attached to the rear leg 5 by, for example, screws or adhesive. In addition, a front damper 34 is provided at the corner of the left and right connecting part 6 of the front leg 3. This 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 direct contact between the rear leg 5 and the corner of the left and right connecting part 6 of the front leg 3 when nesting with another chair of the same structure in the front-rear direction with the seat 20 flipped up, thereby reducing noise during impacts and collisions.

The leg frame 2 of this embodiment is formed so that the seat support 4 and the front leg 3 are gradually offset inward toward the tip side with respect to the rear leg 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 2 is narrower than the inner leg width (the inner distance between the left and right rear legs 5) of the rear leg 5 when the left and right leg frames 2 are assembled. As a result, when multiple chairs 1 are lined up in the front-to-rear direction, the left and right front legs 3, 3 of the other rear chair fit 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 each of the front legs 3 and rear legs 5, but the provision of casters 38 is not a required configuration for the present invention.

The backrest 7 is a resin molded product in which the back frame 7a, the backrest surface 7b, and the cylindrical attachment parts (receiving ports) 7c are integrally molded by injection molding at the lower end parts of both sides of the back frame 7a. In a plan view, the middle part in the left-right direction is curved backward, and in a side view, the part slightly below the center in the up-down direction is curved forward and convex. In addition, the backrest surface 7b has many small holes 7d that penetrate in the front-to-back direction.

As shown in FIG. 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 at the upper end of the rear leg 5, which tapers upward. In other words, 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 when fitted together, they are fixed to each other, for example, by screws.

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. The cushion 22 placed on the inner shell 23 is wrapped in the upholstery 21, and the periphery of the upholstery 21 is sandwiched between the seat frame 24 and the inner shell 23, and the seat frame 24 and the inner shell 23 are overlapped and screwed together to form an integrated structure. 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 guaranteed by the seat frame 24.

In addition, a bow-shaped horizontal bar 25 that protrudes toward the floor is provided at approximately the center of both the left and right sides of the seat frame 24. This horizontal bar 25 is provided to abut against the left and right leg connecting pipes 8 that are fitted between the horizontal connecting parts 6 of the legs, and to support the entire seat frame 24.

As shown in FIG. 5, the seat frame 24 has a resilient buffer pad 26 at the back of the horizontal rail 25 that crosses almost the center of the seat frame 24, where the back of the horizontal rail 25 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 pressed into a hole (not shown) provided in the horizontal rail 25, and is disposed, for example, on both the left and right sides 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 pipe 8 on the leg side, preventing the generation of impact noise and providing a buffering effect, and keeping the seat 20 at a height that allows it to be in 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.

In addition, as shown in Figures 8 and 9, the seat frame 24 is provided with through holes 39 for mounting the pivot 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 Figure 3, the through holes 39 are provided so that the pivot 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 rearward (toward the backrest 7) from the vertical line Lv passing through the rotation shaft portion 14 of the pivot support shaft member 11 when the seat frame 24 is flipped up to take a vertical position, and thus, when the seat 20 is flipped up around the rotation 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. As shown in Figure 9, the entrance of the through hole 39 is provided with a countersunk hole 30 for receiving the head 13 of the pivot support shaft member 11, and a structure for preventing the friction resistance imparting member 15 from rotating, such as a recess 31. The pivot support shaft member 11 is inserted into these through holes 39, and the screw 12 at the tip of the pivot support shaft member 11 is screwed into the screw hole 35 (see Figure 6) of the seat support portion 4, thereby rotatably connecting the leg frame 2 and the seat frame 24.

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 (a position in which the seat 20 is used) and a vertical position (a storage position in which the seat 20 is raised up and stands up along the backrest 7).

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 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.

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 in order to facilitate the ischial sitting position. In other words, 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 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 a frame shape in the front, rear, left and right directions that is the same 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, i.e., a gentle, roughly S-shaped shape (hereinafter referred to as a spline shape) (see FIG. 2).
They are layered neatly.

The inner shell 23 and the seat frame 24 are resin molded products that have 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 still having 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 that surrounds the boss portion 32 of the through hole 39 is formed on the periphery of the inner shell 23 that overlaps with the part where the rotating support shaft member 11 of the seat frame 24 penetrates, and they are overlapped without any gaps.

In this embodiment, as shown in Figs. 10, 12 to 15, and 16, the inner shell 23 has a flange-shaped extension 27 that protrudes 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 vertical 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 when the cushion 22 is extended around 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, thereby improving the appearance of the seat 20 (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 periphery of the seat 20 into a flat shape.

In addition, even if the peripheral portion 22a of the cushion 22 abuts against the extension portion 27 and is pressed from the outside to the inside by the upholstery 21, the extension portion 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 portion 27. This prevents the cushion material from being crushed and wrinkles from forming in the skin material, and the sharp shape of the extension portion 27 can be used to improve the stability of the appearance of the seat 20.

Here, if the inner shell 23 does not have the extension 27, the peripheral edge of the cushion 22 is formed long downward and, for example, wrapped 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 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 create 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 Figure 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. This makes it easy to make the outer periphery of the seat 20 flat.

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 than 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 create more space than necessary, and the chair 1 can be made smaller while still ensuring the area of the seat 20.

In the present embodiment, the peripheral portion 22a of the cushion 22 and the extension 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 extension 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 extension 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 extension portion 27 in the vertical 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 extension portion 27, and the extension 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.

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 near 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 the 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 pivot support shaft member 11, and may be provided.

Next, the fastening structure of the periphery of the upper upholstery 21 will be described in detail with reference to Figures 10 to 17. As shown in Figures 12 to 14, the periphery 21a of the upper upholstery 21 is provided with locking members 28 on both sides and locking members 29 at the front and rear ends. The locking members 28, 29 may be, for example, a flat polypropylene cord (commonly known as 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 mentioned 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 so as to encase 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, the edges of both sides of the inner shell 23 in the seat of this embodiment are almost linear in the front-rear direction, but curve gently in an S-shape with respect to the horizontal plane, so that flexibility along the bottom surface of the groove 23c of the inner shell 23 is required, but flexibility along the side surface of the groove 23c is not required. Therefore, the locking member 28 is placed horizontally in the groove 23c (i.e., the thickness direction is the direction of insertion 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.

As shown in Figs. 11 to 14 and 16, a pair of ribs 23b that protrude downward along the outer periphery are provided at both sides at a fixed interval on the peripheral portion on both sides of the back surface of the inner shell 23, and a pair of ribs 23e are also provided at the front end and 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 on both sides of the inner shell 23. For this reason, the pair of ribs 23b and the groove 23c are formed almost linearly in the front-rear direction (i.e., extending almost 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, the inner shell 23 has ribs to ensure the rigidity of the inner shell 23 in addition to the four ribs 23b and 23e. The grooves 23c and 23f house the locking members 28 and 29 of the upper upholstery 21. It is preferable that the width of the groove 23c is at least slightly wider than the width of the PP cord plus the thickness of the storage bag 21b, and the width of the groove 23f is at least slightly wider than the thickness of the PP cord plus the thickness of the upper upholstery 21.

In this embodiment, the grooves 23c provided on both sides of the width of the inner shell 23 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 to provide flexibility that conforms to the shape of the inner shell 23. In this embodiment, the width of the grooves 23c must be set to at least the same as or slightly wider than the width of the locking member 28, but it is preferable that the width of the grooves 23c is slightly wider than the width of the PP cord plus 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 the groove 23f needs to be set at least wider than the thickness of the PP cord plus the thickness of the upholstery 21, but it is preferable that the width be such that the locking member 28 and the upholstery 21 can be inserted without any problems and will not come loose.

As shown in Figures 12 and 13, the upper upholstery 21 runs from the front surface of the seat 20, past the extension 27, around the back side of the inner shell 23 in an approximately horizontal direction, and the periphery 21a passes over the rib 23b and goes upward toward the bottom of the groove 23c. In other words, the groove 23c is bent at about 90° in the direction in which the tension of the upper upholstery 21 acts, so that they are not on the same line, and the direction of tension 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.

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 on both sides in the width direction of the locking member 28. As a result, when the locking member 28 is provided in the groove 23c, it is provided at the bottom between the locking parts 23d, and when the locking member 28 provided in the groove 23c is pulled and tries to come out, both sides in the width direction are caught by the locking parts 23d to prevent it from coming out. Therefore, it is desirable that the distance between the pair of locking parts 23d is shorter than the length of the locking member 28 in the width direction. The shape of the locking parts 23d is not limited to a claw shape, and may be a convex part or the like as long as it can prevent the locking member 28 from coming out of the groove 23c. In addition, in this embodiment, since the inner shell 23 is a resin molded product, the groove 23c and the locking parts 23d can be integrally formed when the inner shell 23 is formed.

As shown in Figures 10, 11 and 16, in this embodiment, the locking portions 23d are arranged at, for example, five locations at approximately equal intervals from one groove portion 23c, and are arranged 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 can 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.

On the other hand, as shown in Figs. 12 and 13, the seat frame 24 has a pier-shaped retaining portion 24a formed in a position facing the groove 23c of the inner shell 23, which fits into the groove 23c. The retaining portion 24a is not constantly pressed against the locking member 28 housed in the groove 23c, but is arranged 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 designed to prevent the locking member 28 housed in the groove 23c from coming out of the groove 23c by abutting against it. 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.

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 periphery of 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.

Here, because the seat frame 24 has a narrow frame shape, if an attempt is made to tighten the periphery 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 periphery 21a of the upper upholstery 21 is fastened to the periphery of the inner shell 23 and the seat frame 24, so that the periphery 21a of the upper upholstery 21 can be contained within the seat frame 24, improving the appearance.

According to the seat 20 of the chair 1 configured as described above, the inner shell 23 has a 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, improving the appearance of the seat 20.

In addition, even if the peripheral portion 22a of the cushion 22 abuts against the extension portion 27 and is pressed from the outside to the inside by the upholstery 21, the extension portion 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 portion 27. This prevents the cushion 22 from being crushed and makes it less likely for the upholstery 21 to wrinkle, improving the stability of the appearance of the seat 20.

Although the above embodiment is one example of a preferred form for implementing 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, the above embodiment describes an example in which the structure of the present invention is applied to the seat 20 of a 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 that fits the periphery of the upper 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 upper upholstery 21 may be applied to the fastening structure.

In the above embodiment, a resin molded product is used as the inner shell 23, but this is not limiting, 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 can be formed by additional processing after the plywood is formed. In addition, in the case of a plywood inner shell, although not shown, grooves 23c and 23f may be formed by groove processing, or grooves 23c and 23f and locking portion 23d may be provided using rails (corresponding to ribs 23b and 23e) made of a separate material such as a steel plate.

In addition, the locking member 28 is not limited to a flat part with 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 that can follow the shape of the inner shell 23 and can be prevented from coming off by being locked to the locking portion 23d. For example, when using a locking member with a triangular cross section, if the ridge portion is inserted toward the bottom of the groove, the locking member 28 can be easily pushed into the groove 23c, and then the locking member 28 can be prevented from coming off by being caught by the locking portion 23d. In addition, even if 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 managed to be such that the locking member 28 can be inserted and cannot be pulled out.

In addition, in the above embodiment, the seat of a chair is used 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, headrest, armrest, etc.

1 chair 20 seats (structure)
21 Upper covering material (skin material)
21a Edge (edge of skin material)
21b Storage bag 22 Cushion (cushion material)
23 Inner shell 23c Groove portion 23d Locking portion 24 Seat frame (outer shell)
24a: retaining portion 28: locking member

Claims (4)

A chair structure in which a cushioning material is layered on an inner shell and covered with a skin material, the periphery of the skin material is wrapped around the back side of the inner shell, a locking member provided on the periphery of the skin material is fastened to the back side of the inner shell , and the inner shell is supported from below by an outer shell ,
the inner shell has a groove portion that accommodates the locking member on a back side thereof, and a locking portion that engages with the locking member when the locking member accommodated in the groove attempts to come out of the groove, thereby preventing the locking member from coming out,
the locking member is flat and flexible enough to conform to a back surface of the inner shell that is the bottom of the groove of the inner shell, and is accommodated in the groove with a front surface thereof conforming to the back surface of the inner shell that is the bottom of the groove of the inner shell ,
The outer shell has a retaining portion that is disposed opposite the locking member housed in the groove with a clearance therebetween and that abuts against the locking member when the locking member housed in the groove attempts to come out of the groove to prevent the locking member from coming out.
A chair structure characterized in that 2. The chair structure according to claim 1 , wherein the fastening member is accommodated in a storage bag provided on the periphery of the covering material. The structure is a chair seat, and the groove portion that accommodates the locking member is formed so as to extend in the front-to-rear direction along both the left and right edges of the back surface of the inner shell of the seat. A chair comprising a structure according to any one of claims 1 to 3 .

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