Chair

Abstract

To provide a horizontally recyclable chair that offers a high level of seating comfort.SOLUTION: A chair comprises a backrest, a seat, and legs. The seat comprises: a cushion 31, which features a mesh structure of thermoplastic resin with a thickness; a seat plate, which supports the cushion 31; and an outer fabric, which covers the cushion. The upper surface 31b of the cushion 31 features: a first area P1 with first hardness to support the buttocks of a seated individual; a second area P2, positioned outside the first area P1 in a planar view and exhibiting second hardness greater than the first hardness; and a third area P3, positioned outside the second area P2 in a planar view and exhibiting third hardness higher than the second hardness.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a chair. [Background technology]

[0002] Conventionally, there are chairs whose hardness changes depending on the position of the seat (see, for example, Patent Document 1). Patent Document 1 discloses a chair that is comfortable to sit on, in which the seat uses a cushioning material that includes a hard part and a soft part that is softer than the hard part and is provided in at least a part of a pressure-receiving area that receives the load from the body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-289999 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, it has been desired that office chairs be manufactured using horizontally recyclable materials that use resources semi-permanently. However, the cushioning material in the above-mentioned conventional chairs is made of foamed urethane, which is a thermosetting resin. Therefore, while the cushioning material waste in conventional chairs can be recycled as a material with limited uses by processing it into urethane chips, or can be thermally recycled as fuel, it cannot be horizontally recycled into the same product as before recycling. Therefore, it is difficult to reuse the waste in conventional chairs as horizontally recycled material.

[0005] Therefore, the present invention provides a chair that is horizontally recyclable and comfortable to sit on. [Means for solving the problem]

[0006] A chair according to a first aspect of the present invention is a chair having a backrest, a seat and legs, wherein the seat has a cushion formed of a mesh structure made of a thermoplastic resin, a seat plate supporting the cushion, and an outer cover covering the cushion, and the upper surface of the cushion has a first point having a first hardness and supporting the buttocks of a seated person, a second point located outside the first point in a planar view and having a second hardness higher than the first hardness, and a third point located outside the second point in a planar view and having a third hardness higher than the second hardness.

[0007] According to the first aspect, the buttocks of the seated person sink deeper into the seat as they move inward in a plan view, and are in a state of being embraced. In this state, the shallower the part of the seated person's buttocks sink into the cushion, the more supported it is by the part of the cushion with higher hardness. Therefore, when sitting, the buttocks are less likely to slip outward, and the person sits in a stable state. This results in a chair that is comfortable to sit on. Furthermore, since the cushion is formed of a network structure made of a thermoplastic resin, unlike cushions formed of urethane foam, waste cushions can be reused as horizontally recycled materials. As a result, a chair that is horizontally recyclable and comfortable to sit on can be provided. Furthermore, since the cushion is formed from a mesh structure, breathability can be easily ensured, and since it is made of resin, it can also be easily cleaned.

[0008] A chair according to a second aspect of the present invention is the chair according to the first aspect described above, wherein the cushion further has a front portion located forward of the first portion and having a hardness equal to or less than the first hardness.

[0009] According to the second aspect, the front portion of the cushion that the thighs of the seated person contact is set to a hardness equal to or lower than the first hardness, so that the thighs of the seated person contact the lower hardness portion of the cushion. This reduces the feeling of pressure on the thighs. This further improves the comfort of sitting.

[0010] A chair according to a third aspect of the present invention is a chair according to the first or second aspect above, wherein the hardness distribution on the upper surface of the cushion may be the same as the hardness distribution on the lower surface of the cushion when viewed from the vertical direction.

[0011] According to the third aspect, a structure that expresses the hardness of the cushion is provided so as to penetrate the cushion in the vertical direction. If the distribution of hardness changes according to the depth position based on the upper surface of the cushion, the sitting comfort may change according to the size of the area that the seated person's buttocks touch when the buttocks sink in. Therefore, according to the third aspect, a constant sitting comfort can be obtained regardless of the body type, weight, etc. of the seated person.

[0012] A chair according to a fourth aspect of the present invention is a chair according to any one of the first to third aspects above, wherein the cushion includes the first location and has a pair of first regions spaced apart on the left-right center of the upper surface, and a central region located between the pair of first regions and including the left-right center of the upper surface, and the hardness of the central region may be higher than the first hardness.

[0013] According to the fourth aspect, the first region having the first hardness provides a comfortable seating experience where the buttocks sink in, while the central region having a fourth hardness higher than the first hardness holds the buttocks in place even more. This further improves seating comfort. Also, compared to a configuration in which the central portion of the cushion in the left-right direction has the first hardness, the cushion is less likely to sag.

[0014] A chair according to a fifth aspect of the present invention is a chair according to any one of the first to fourth aspects above, wherein the cushion is arranged along the outer edge of the seat plate and has a convex portion that engages with the outer edge.

[0015] According to the fifth aspect, the protrusion engages with the outer edge of the seat plate, making it difficult for the cushion to slip off the seat plate, and therefore the cushion can be stably supported by the seat plate. In addition, by interposing a convex portion between the outer covering and the outer edge of the seat plate, the outer covering abuts against the outer edge of the seat plate under tension, sandwiching the convex portion, thereby making it difficult for the outer covering to be damaged even if the outer edge of the seat plate has an angular shape. Furthermore, the worker can hook his / her fingers on the protruding portion, which makes it easier for the worker to grasp the cushion. Effect of the Invention

[0016] According to the present invention, a chair that is horizontally recyclable and comfortable to sit on can be provided. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a chair according to a first embodiment, seen from the side. [Diagram 2] FIG. 1 is a perspective view of a chair according to a first embodiment, seen from the rear (backrest side). [Diagram 3] 2 is a diagram showing a cross section perpendicular to the left-right direction at the center position in the left-right direction of the seat according to the first embodiment. FIG. [Figure 4] 4 is an enlarged cross-sectional view of the seat according to the first embodiment, showing a portion IV in FIG. 3. [Diagram 5] FIG. 2 is a diagram showing the structure of a network structure. [Figure 6] FIG. 4 is a diagram showing the hardness distribution on the upper surface of the cushion according to the first embodiment. [Figure 7] FIG. 4 is a diagram showing the distribution of each structure of the network structure in the cross section of the cushion shown in FIG. [Figure 8] FIG. 11 is a diagram showing the hardness distribution on the upper surface of the cushion according to the first modified example of the first embodiment. [Figure 9] 13 is a diagram showing the hardness distribution on the upper surface of a cushion according to a second modified example of the first embodiment. FIG. [Figure 10]FIG. 11 is a diagram showing the hardness distribution on the upper surface of a cushion according to a third modified example of the first embodiment. [Figure 11] FIG. 11 is a perspective view of a chair according to a second embodiment, seen from the front. [Figure 12] FIG. 11 is a diagram showing the hardness distribution on the upper surface of the cushion according to the second embodiment. [Figure 13] FIG. 11 is a diagram showing the hardness distribution on the upper surface of a cushion according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions will be given the same reference numerals. Then, duplicated descriptions of those components may be omitted. In the following description, the directions such as front, back, up, down, left and right are the same as the directions of a person (seater) sitting in a chair in a normal posture. That is, the direction in which the seater faces forward is referred to as "forward," and the opposite direction is referred to as "rear." Furthermore, in each figure, the arrow UP indicates upward, the arrow FR indicates forward, and the arrow LH indicates leftward, respectively.

[0019] [First embodiment] Fig. 1 is a perspective view of the chair 1 according to the first embodiment as seen from the side. Fig. 2 is a perspective view of the chair 1 according to the first embodiment as seen from the rear (backrest side). 1 and 2, the chair 1 of the first embodiment includes legs 2 installed on a floor surface F, a box-shaped support base 3 installed on the upper part of the legs 2, a seat support member 4 attached to the upper part of the support base 3, a seat 6 supported on the upper part of the seat support member 4 so as to be adjustable in the front-rear direction, a backrest support 7 pivotally supported on both the left and right sides of the support base 3 and tiltable by a reclining mechanism (not shown) in the support base 3, a backrest main body 8 attached to the front side of the upper part of the backrest support 7, and a pair of left and right armrests 10 attached to the front edge of the lower part of the backrest support 7 on which the elbows of a seated person are placed. The backrest support 7 and the backrest main body 8 form a backrest 9 that supports the weight of the back of the seated person.

[0020] The legs 2 have a contact portion that contacts the floor surface F. The legs 2 extend from the contact portion toward the seat 6, dissipating the seating weight from the seat 6 to the floor surface F. The legs 2 have a multi-leg 21 with casters 21A, and a pillar 22 that rises from the center of the multi-leg 21 and incorporates a gas spring (not shown) that serves as a lifting mechanism.

[0021] The leg 22 includes an outer cylinder 23 and an inner cylinder 24. The outer cylinder 23 forms the lower part of the leg 22. The outer cylinder 23 is non-rotatably fitted and supported by the multi-leg 21. The inner cylinder 24 forms the upper part of the leg 22. The upper end of the inner cylinder 24 fixes and supports the support base 3. The lower part of the inner cylinder 24 is supported by the outer cylinder 23 so as to be rotatable in the horizontal direction.

[0022] The support base 3 has built-in mechanisms for adjusting the elevation of the legs 22 and for reclining the backrest 9.

[0023] The seat receiving member 4 is connected to the upper part of the support base 3 so as to be able to swing. The seat receiving member 4 is adapted to be displaced in the front-rear direction in conjunction with the tilting movement of the backrest support 7. The seat receiving member 4 has a pair of left and right side frame parts 26. The left and right side frame parts 26 are arranged so as to be parallel to each other. A guide rail protrudes from the upper part of each of the left and right side frame parts 26 to support the seat 6 so that it can slide freely in the front-rear direction. In this embodiment, the legs 2, support base 3 and seat receiving member 4 constitute a support structure 5 that supports the seat 6 from below.

[0024] The seat 6 supports the area from the buttocks to the thighs of a seated person. The seat 6 has a seat plate 30 (see FIG. 3) made of hard resin that receives the seating load, and a pair of frame receiving parts 34 provided at positions spaced apart in the left-right direction on the underside of the seat plate 30. The seat plate 30 is formed in a circular or rectangular shape in plan view so that its shape in plan view generally matches the shape of the seat 6 in plan view. The left and right frame receiving parts 34 are provided at positions corresponding to the left and right side frame parts 26 of the seat receiving member 4, and extend along the front-rear direction. The frame receiving parts 34 are formed to be longer in the front-rear direction than the guide rails of the side frame parts 26. The left and right frame receiving parts 34 are formed as integral parts with the seat plate 30. However, the frame receiving parts 34 may be formed as separate parts from the seat plate 30 and fixed to the seat plate 30 by a fixing means. Details of the seat 6 will be described later.

[0025] The main part of the backrest support 7 is made of a metal material such as an aluminum alloy. The backrest support 7 includes a pair of left and right main frames 72 spaced apart in the left-right direction, and a connecting frame 73 extending in the left-right direction and connecting the upper ends of the main frames 72. The left and right main frames 72 are formed in a substantially L-shape in a side view, and have an upright portion 72a that stands upward from a lower rear position of the seat 6, and a forward-facing arm portion 72b that curves and extends forward from the lower end of the upright portion 72a. The front end of the forward-facing arm portion 72b is connected to the shaft of the reclining mechanism provided on the support base 3 as described above. In addition, the upright portions 72a of the left and right main frames 72 are inclined outward in the left-right direction so that the distance between them gradually increases as they move upward.

[0026] The backrest body 8 supports the back of the seated person. The backrest body 8 has a resin backrest frame 75 and a tensioning material 76 that is stretched over the backrest frame 75 and directly receives the input load from the back of the seated person. The backrest frame 75 is formed in an inverted triangular shape in front view, with the width of the left and right frame sides 75s gradually narrowing downward, and the upper ends of the left and right frame sides 75s connected by an upper frame side 75u extending in the left and right direction. An upper connecting arm 77 protruding backward from an upper region and a lower connecting arm 78 protruding backward from a lower region are extended from each of the left and right frame sides 75s of the backrest frame 75. The upper connecting arm 77 is connected to the upper region of the upright portion 72a of the corresponding main frame 72 on the left and right sides of the backrest support 7, and the lower connecting arm 78 is connected to the lower region of the upright portion 72a of the corresponding main frame 72 on the left and right sides of the backrest support 7.

[0027] The seat 6 will be described in detail mainly with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing a cross section perpendicular to the left-right direction at the center position in the left-right direction of the seat 6 according to the first embodiment. Fig. 4 is an enlarged cross-sectional view of the seat 6 according to the first embodiment, showing part IV in Fig. 3. Note that the padding 33 and the outer cover 32 are omitted from Fig. 3. The seat plate 30 has a locking claw 30a provided on the outer periphery. The locking claw 30a is provided on the bottom surface of the seat plate 30. The locking claw 30a protrudes toward the outer edge 30b side of the seat plate 30. For example, a plurality of locking claws 30a are provided at intervals along the outer edge 30b of the seat plate 30.

[0028] In addition to the above-mentioned seat plate 30, the seat 6 further includes a cushion 31 arranged above the seat plate 30, an outer cover 32 covering the cushion 31, and a padding 33 interposed between the cushion 31 and the outer cover 32.

[0029] The cushion 31 is disposed along the upper surface of the seat plate 30 and is supported by the seat plate 30. The cushion 31 has a thickness in the vertical direction, and has an upper surface 31b that is a seating surface and a lower surface 31c that faces the upper surface of the seat plate 30. The entire cushion 31 is formed as a single unit. The cushion 31 is formed of a net structure made of a thermoplastic resin (see FIG. 5). A single material made of polyethylene is used as the thermoplastic resin. The net structure is formed into a single member having a desired shape by intertwining a plurality of fibers (or filamentous resin). For example, the plurality of fibers are intertwined so as to be bonded to each other by melting. The cushion 31 has gaps between the fibers of the net structure, and the fibers of the net structure are elastically deformed so as to reduce the gaps, thereby exhibiting cushioning properties. The cushion 31 has a distribution of hardness. For example, the hardness of the cushion 31 changes depending on the density of the fibers of the net structure. However, the hardness of the cushion 31 may vary depending on the thickness of the fibers of the network structure.

[0030] The cushion 31 is arranged so as to overlap the entire seat plate 30 when viewed from above. The cushion 31 has a protrusion 31a protruding downward. The protrusion 31a is provided on the outer periphery of the bottom of the cushion 31. It is provided at a position of the cushion 31 that protrudes outward from the seat plate 30 in a plan view. The protrusion 31a is provided around the entire periphery of the cushion 31. However, the protrusion 31a may be provided only on a part of the outer periphery of the cushion 31. The protrusion 31a is arranged along the outer edge 30b of the seat plate 30. The protrusion 31a engages with the outer edge 30b of the seat plate 30 so that the displacement of the cushion 31 along the upper surface of the seat plate 30 is restricted.

[0031] The padding 33 is provided so as to cover the cushion 31. The padding 33 directly covers the cushion 31. The padding 33 is not attached to the cushion 31, but may be attached to the cushion 31 by a removable attachment means such as sewing or tacking. The padding 33 is formed of a nonwoven fabric. By covering the cushion 31, the padding 33 suppresses the unevenness of the outer surface of the cushion 31 from appearing on the outer surface of the seat 6. The unevenness of the outer surface of the cushion 31 is formed by the fibers and voids of the net structure. The nonwoven fabric used for forming the padding 33 has smaller gaps between the fibers than the net structure that forms the cushion 31. However, the gaps between the fibers of the nonwoven fabric do not need to be uniform throughout the padding 33, and it is sufficient that the mode or average size of the gaps is smaller than that of the net structure.

[0032] The padding 33 covers all the parts of the cushion 31 that are not covered by the seat plate 30. Before covering the cushion 31, the padding 33 is formed in a sheet shape larger than the cushion 31 in a plan view. The padding 33 passes from above the cushion 31 to the side of the cushion 31, straddles the convex portion 31a of the cushion 31 at the bottom, and wraps around to the bottom of the seat plate 30. The outer peripheral edge of the padding 33 is located below the outer peripheral portion of the seat plate 30. A bag-shaped string insertion portion 33a is provided on the outer peripheral edge of the padding 33 over approximately the entire circumference. A string having an end is inserted inside the string insertion portion 33a. The string tightens the outer peripheral edge of the padding 33 so that the outer peripheral edge of the padding 33 is smaller than the outer shape of the seat plate 30 in a plan view. Both ends of the string are pulled out to the outside through a pull-out opening formed in the string insertion portion 33a and fixed to each other. The cord insertion portion 33 a is engaged with a locking claw 30 a of the seat plate 30 .

[0033] The outer cover 32 integrally forms the upper surface and the side surfaces of the seat 6. The side surfaces are surfaces that face in a direction perpendicular to the up-down direction. The outer cover 32 covers the entire outer surface of the padding 33, thereby covering the portion of the cushion 31 that is covered with the padding 33. The outer cover 32 is made of a cloth material, a vinyl leather material, a natural leather material, or the like.

[0034] The outer cover 32 has a shape similar to that of the padding 33, and passes from above the cushion 31 to the side of the cushion 31, straddles the protruding portion 31a of the cushion 31 at the bottom, and wraps around to the bottom of the seat plate 30. A bag-shaped string insertion portion 32a through which a string is inserted is provided on the outer peripheral edge of the outer cover 32 over approximately the entire circumference. The string tightens the outer peripheral edge of the outer cover 32 so that the outer peripheral edge of the outer cover 32 is smaller than the outer shape of the seat plate 30, preferably the outer peripheral edge of the padding 33, in a plan view. Both ends of the string are pulled out to the outside through a pull-out opening formed in the string insertion portion 32a and fixed to each other. The string insertion portion 33a is engaged with a locking claw 30a of the seat plate 30. Furthermore, the outer peripheral edge of the outer skin 32 and the outer peripheral edge of the padding 33 abut under tension against the outer edge 30b of the seat plate 30, sandwiching the convex portion 31a of the cushion 31, so that even if the outer edge 30b of the seat plate 30 has an angular shape, it is less likely to break.

[0035] Here, the hardness of the cushion 31 will be described with reference to Fig. 6. Fig. 6 is a diagram showing the distribution of hardness on the upper surface 31b of the cushion 31 according to the first embodiment. Note that the hardness of the cushion 31 in the following description is a value measured using a rubber hardness meter (model number: Asker rubber hardness meter type F) manufactured by Kobunshi Keiki Co., Ltd.

[0036] The hardness distribution of the upper surface 31b and the lower surface 31c of the cushion 31 will be described. In this embodiment, the hardness distribution of the upper surface 31b of the cushion 31 is symmetrical and coincides with the hardness distribution of the lower surface 31c of the cushion 31 in the height direction. In other words, below an area set to a certain hardness on the upper surface 31b of the cushion 31, an area of ​​the same hardness on the lower surface 31c of the cushion 31 is arranged. In the following description, only the hardness distribution of the upper surface 31b of the cushion 31 will be described. Each area on the upper surface 31b of the cushion 31 is defined as follows according to the hardness distribution of the upper surface 31b. In this embodiment, the areas described later are separated from each other by a boundary line that extends linearly in the front-rear or left-right direction in a plan view. The upper surface 31b of the cushion 31 includes a pair of a first area R1, a second area R2, and a third area R3.

[0037] Each first region R1 is a region that supports the buttocks of a seated person. All parts of the first region R1 support any part within a range from the buttocks to the rear of the thighs of the seated person. The first region R1 includes a part that supports the ischial bones of the seated person. In other words, the first region R1 is a region that spreads in the front-rear and left-right directions from the most loaded point where the seating load is maximized in the distribution of the seating load acting on the cushion 31. The first region R1 is located inside the outer edge of the upper surface 31b of the cushion 31. Each first region R1 has a rectangular shape in a plan view. The pair of first regions R1 are spaced apart from each other on the center in the left-right direction on the upper surface 31b of the cushion 31. Each first region R1 includes the center in the front-rear direction on the upper surface 31b of the cushion 31. With respect to the size in the front-rear direction of each region R1, the front part of the upper surface 31b of the cushion 31 with respect to the center in the front-rear direction is larger than the rear part.

[0038] The second region R2 is adjacent to the outside of the pair of first regions R1 in a plan view. The outside is a direction from a reference position toward the outer edge of the upper surface 31b of the cushion 31 in a plan view. In other words, the second region R2 is in a direction from the first region R1 toward the outer edge of the upper surface 31b of the cushion 31 in a plan view. The second region R2 is located inside the outer edge of the upper surface 31b of the cushion 31. The second region R2 surrounds the pair of first regions R1 together. In the illustrated example, the second region R2 has a U-shaped plan view shape that is open to the front, and surrounds the pair of first regions R1 from the rear and both left and right sides. In the second region R2, the left and right size of both left and right sides extending in the front and rear direction is smaller than the front and rear size of the rear part extending in the left and right direction.

[0039] The third region R3 includes a region where the seating load does not directly act. The third region R3 is adjacent to the outside of the second region R2 in a plan view. That is, the third region R3 is in a direction from the second region R2 toward the outer edge of the upper surface 31b of the cushion 31 in a plan view. The third region R3 is located on the opposite side of the pair of first regions R1 across the second region R2, and surrounds the second region R2. In the illustrated example, the third region R3 has a U-shaped plan view shape that is open to the front, and surrounds the second region R2 from the rear and both left and right sides. The third region R3 includes the outer periphery of the upper surface 31b of the cushion 31. That is, the third region R3 includes at least a part of the outer edge of the upper surface 31b of the cushion 31. In the illustrated example, the third region R3 includes both left and right side edges of the upper surface 31b of the cushion 31, and is spaced from the front and rear edges of the upper surface 31b of the cushion 31 in the front-rear direction. In the third region R3, the size in the left-right direction of both left and right side portions extending in the front-rear direction is greater than the size in the front-rear direction of a rear portion extending in the left-right direction.

[0040] The pair of first regions R1, second region R2, and third region R3 can be defined as follows. The third region R3 is an outer peripheral region including the outer peripheral portion of the upper surface 31b of the cushion 31. The pair of first regions R1 are central regions located inside the third region R3. The inside is a direction from a reference position toward the center of the upper surface 31b of the cushion 31 in a plan view. The pair of first regions R1 are located on both the left and right sides of the center in the left-right direction of the upper surface 31b of the cushion 31. The second region R2 is an intermediate region located between the third region R2 and the first region R1. The second region R2 is adjacent to the inside of the third region R3 and adjacent to the outside of the first region R1.

[0041] At a position in the front-rear direction where the first region R1, the second region R2, and the third region R3 are aligned in the left-right direction, the left-right size of the first region R1 and the third region R3 is larger than the left-right size of the second region R2. At a position in the front-rear direction where the first region R1, the second region R2, and the third region R3 are aligned in the left-right direction, the front-rear size of the second region R2 is smaller than the front-rear size of the first region R1 and larger than the front-rear size of the third region R3.

[0042] The hardness of the first region R1, the second region R2, and the third region R3 is set as follows. Here, a first virtual half line L1, a first location P1, a second location P2, and a third location P3 are defined. The first location P1 is an arbitrary point in the first region R1. The first virtual half line L1 extends outward from the first location P1 in a plan view, and passes through the first region R1, the second region R2, and the third region R3 in succession. In FIG. 6, as an example of the first virtual half line L1, a first virtual half line L1 extending outward in the left-right direction from the first location P1 is shown. For example, the first virtual half line may extend backward from the first location P1. The second location P2 is an arbitrary point on the first virtual half line L1 in the second region R2. The third location P3 is an arbitrary point on the first virtual half line L1 in the third region R3. That is, the second location P2 is located outside the first location P1, and the third location P3 is located outside the second location P2. The first location P1 has a first hardness. The second location P2 has a second hardness. The second hardness is higher than the first hardness. The third location P3 has a third hardness. The third hardness is higher than the second hardness.

[0043] The first region R1 has a uniform hardness throughout. The second region R2 may have a uniform hardness throughout, or may have a distribution of hardness. For example, the left and right side portions extending in the front-rear direction in the second region R2 may be formed so that the hardness increases from the front end toward the rear. For example, the rear portion extending in the left-right direction in the second region R2 may be formed so that the hardness increases from the center in the left-right direction toward the outside in the left-right direction. In these cases, the second region R2 may have a plurality of small regions with different hardness from each other, or may be formed so that the hardness changes continuously. In this embodiment, the hardness of all the points in the second region R2 is higher than the hardness of the first region R1. The third region R3 is the same as the second region R2.

[0044] Since the first location P1, the second location P2, and the third location P3 are arranged as described above, the cushion 31 has the following configuration: The cushion 31 has a first hardness at a position where the buttocks of a seated person come into contact, a second hardness outside the first hardness, and a third hardness outside the second hardness.

[0045] The upper surface 31b of the cushion 31 further includes a fourth region R4 (central region), a fifth region R5, and a sixth region R6. The fourth region R4 includes a central portion in the left-right direction on the upper surface 31b of the cushion 31. The fourth region R4 is a region between a pair of the first regions R1. The fourth region R4 includes a center in the left-right direction on the upper surface 31b of the cushion 31. The hardness of the fourth region R4 is set as follows. Here, the fourth point P4 is defined in relation to the above-mentioned first point P1. The fourth point P4 is an arbitrary point on a second imaginary half line L2 that extends inward in the left-right direction from the first point P1 in a plan view in the fourth region R4 and passes continuously through the first region R1 and the fourth region R4. The fourth point P4 has a fourth hardness. The fourth hardness may be higher than the first hardness, but is preferably equal to or higher than the second hardness and equal to or lower than the third hardness. In this embodiment, the fourth region R4 has a uniform hardness. Since the fourth region R4 is disposed relative to the first region R1 as described above, the cushion 31 has a hardness in the left-right central portion that is higher than the first hardness.

[0046] The fifth region R5 supports the front of the thighs of a seated person. The fifth region R5 is located in front of the pair of first regions R1 in a plan view. The fifth region R5 includes the front edge of the upper surface 31b of the cushion 31. The fifth region R5 extends in the left-right direction. The fifth region R5 is adjacent to the front of the first region R1, the second region R2, the third region R3, and the fourth region R4. The hardness of the fifth region R5 is set as follows. Here, the fifth point P5 (front point) is defined in relation to the above-mentioned first point P1. The fifth point P5 is an arbitrary point on the third imaginary half line L3 of the fifth region R5 that extends forward from the first point P1 in a plan view and passes continuously through the first region R1 and the fifth region R5. The fifth point P5 has a fifth hardness. The fifth hardness is equal to or less than the first hardness. In this embodiment, the fifth hardness may be lower than the second hardness, but is preferably lower than the first hardness. Furthermore, the fifth region R5 has a hardness lower at a portion adjacent to the second region R2 than the hardness of the portion of the second region R2 adjacent to the fifth region R5. The same is true for the portions of the fifth region R5 adjacent to the third region R3 and the fourth region R4. In this embodiment, the hardness of the entire fifth region R5 is equal to or lower than the first hardness. The hardness of the portion of the fifth region R5 located in front of the first region R1 is lower than the hardness of the other portions. Since the fifth region R5 is disposed relative to the first region R1 as described above, the cushion 31 has a hardness equal to or lower than the first hardness in front of the position where the buttocks of the seated person hit.

[0047] The sixth region R6 is located behind the pair of first regions R1 in a plan view. The sixth region R6 includes the rear edge of the upper surface 31b of the cushion 31. The sixth region R6 extends in the left-right direction. The sixth region R6 is adjacent to the rear of the third region R3. Any part of the sixth region R6 has a hardness lower than the hardness of a part of the third region R3 adjacent to the any part. In this embodiment, the overall hardness of the sixth region R6 is equal to or lower than the first hardness.

[0048] Furthermore, the protruding portion 31a of the cushion 31 has a hardness higher than the first hardness due to heat treatment after molding. In this embodiment, the entire protruding portion 31a has a hardness higher than the hardness of all parts of the first region R1 and has a hardness equivalent to the third hardness. Note that the protruding portion 31a may have a hardness equal to or higher than the third hardness. Note that the protruding portion 31a formed in the fifth region R5, which has a hardness equal to or lower than the first hardness, also has a hardness equal to the third hardness.

[0049] FIG. 7 is a diagram showing the distribution of each structure of the network structure in the cross section of the cushion 31 shown in FIG. As shown in FIG. 7, the cushion 31 has a structure for providing cushioning properties penetrating in the vertical direction. The structure for providing cushioning properties is the density of fibers in the network structure, the thickness of the fibers, etc. As a result, the cushion 31 is formed so that the hardness distribution on the upper surface 31b and the hardness distribution on the lower surface 31c match when viewed from the vertical direction. As a result, at least the first hardness, the second hardness, and the third hardness are provided at the same positions on the top and bottom of the cushion 31. However, the protrusions 31a provided on the bottom of the cushion 31 may be formed to have different hardnesses from the adjacent portions.

[0050] As described above, the upper surface 31b of the cushion 31 of the chair 1 of this embodiment has a first location P1 having a first hardness and supporting the buttocks of a seated person, a second location P2 located outside the first location P1 in a plan view and having a second hardness higher than the first hardness, and a third location P3 located outside the second location P2 in a plan view and having a third hardness higher than the second hardness. With this configuration, the buttocks of the seated person sink deeper into the seat 6 as they move inward in a plan view, and are in a state of being wrapped up. In this embodiment, the buttocks of the seated person are in a state of being wrapped up from the outside in the left-right direction and from the rear. In this state, the part of the buttocks of the seated person that sinks shallower into the cushion 31 is supported by the part of the cushion 31 with a higher hardness. Therefore, when sitting, the buttocks are less likely to shift outward, and the seated person is in a stable state. Therefore, a chair 1 that is comfortable to sit on is obtained.

[0051] Furthermore, since the cushion 31 is formed of a net-like structure made of a thermoplastic resin, waste of the cushion 31 can be reused as a horizontally recycled material, unlike when the cushion 31 is formed of urethane foam. As a result, a chair 1 that is horizontally recyclable and comfortable to sit on can be provided. Furthermore, since the cushion 31 is formed from a net-like structure, breathability can be easily ensured, and since it is made of resin, it can be easily cleaned.

[0052] The cushion 31 further has a fifth point P5 located in front of the first point P1 and having a hardness equal to or less than the first hardness. With this configuration, the fifth point P5 with which the thighs of the seated person come into contact is set to a hardness equal to or less than the first hardness, so that the thighs of the seated person come into contact with the parts of the cushion 31 with a lower hardness. This reduces the feeling of pressure on the thighs. This further improves the comfort of sitting.

[0053] The hardness distribution on the upper surface 31b of the cushion 31 coincides with the hardness distribution on the lower surface 31c of the cushion 31 when viewed from the top-bottom direction. According to this configuration, the structure that expresses the hardness of the cushion 31 is provided so as to penetrate the cushion 31 in the top-bottom direction. If the hardness distribution changes depending on the depth position based on the upper surface 31b of the cushion 31, the sitting comfort may change depending on the size of the area that the seated person's buttocks touch when the buttocks sink in. Therefore, according to this embodiment, a constant sitting comfort can be obtained regardless of the body type, weight, etc. of the seated person.

[0054] The cushion 31 includes a pair of first regions R1 that include the first location P1 and are spaced apart from each other on the center of the upper surface 31b in the left-right direction, and a fourth region R4 that is located between the pair of first regions and includes the center of the upper surface in the left-right direction. The hardness of the fourth region R4 is higher than the first hardness. With this configuration, the first region R1 having the first hardness provides a comfortable sitting experience in which the buttocks sink, while the fourth region R4 having a fourth hardness higher than the first hardness holds the buttocks in a more difficult position. This further improves the sitting comfort. In addition, the cushion 31 can be prevented from sagging as compared to a configuration in which the center of the cushion 31 in the left-right direction has the first hardness.

[0055] The cushion 31 is disposed along the outer edge 30b of the seat plate 30 and has a protruding portion 31a that engages with the outer edge 30b. With this configuration, the protruding portion 31a engages with the outer edge 30b of the seat plate 30, making it difficult for the cushion 31 to slip relative to the seat plate 30. In particular, in this embodiment, the hardness of the protruding portion 31a is higher than the first hardness, so the above-mentioned effect can be obtained more effectively. Therefore, the cushion 31 can be stably supported by the seat plate 30. Furthermore, the worker can hook his / her fingers on the protrusion 31a, which makes it easier for the worker to grasp the cushion 31.

[0056] The seat 6 includes padding 33 interposed between the cushion 31 and the outer cover 32. This configuration can prevent the unevenness of the outer surface of the cushion 31 from reaching the outer cover 32. This makes it difficult for the unevenness of the outer surface of the cushion 31 to appear on the outer surface of the seat 6, and prevents the cushion 31 being made of a net-like structure from making it less comfortable to sit on.

[0057] In the first embodiment, the fourth region R4 is provided on the upper surface 31b of the cushion 31, but this is not limited to the configuration. As shown in Fig. 8, a pair of first regions R1 on the upper surface 31b of the cushion 31 may be adjacent to each other and integrated, and the fourth region R1 may not be provided.

[0058] In the first embodiment, the second region R2 and the third region R3 of the upper surface 31b of the cushion 31 surround the first region R1 from three directions excluding the front in a plan view, but are not limited to this configuration and may be configured as shown in FIG. 9 or FIG. 10. As shown in FIG. 9, the second region R2 surrounds the pair of first regions R1 together. The second region R2 has a rectangular frame shape in a plan view. That is, the second region R2 surrounds the pair of first regions R1 from both sides in the front-rear direction and both left and right. The third region R3 surrounds the second region R2. The third region R3 has a rectangular frame shape in a plan view. That is, the third region R3 surrounds the second region R2 from both sides in the front-rear direction and both left and right. Even in this configuration, it is preferable that the fifth region R5 is provided in front of the pair of first regions R1. However, as shown in FIG. 10, the fifth region R5 and the sixth region R6 may not be provided. In this case, the third region R3 includes the entire outer edge of the upper surface 31b of the cushion 31. The second region R2 and the third region R3 do not necessarily have to be provided behind the first region R1.

[0059] [Second embodiment] 11 is a perspective view of a chair 101 according to the second embodiment, seen from the front. Note that the configuration other than that described below is the same as that of the first embodiment.

[0060] 11, a chair 101 of the second embodiment is a bench on which multiple users can sit side by side. The chair 101 includes legs 102, a seat 106 that supports the buttocks of the seated person, and a backrest 109 that supports the back of the seated person.

[0061] The legs 102 have a ground contact portion. The legs 102 extend upward from the ground contact portion to release the seating load from the seat 106 to the floor surface F. A pair of legs 102 are provided on the front and rear of both the left and right sides of the chair 101. The seat 106 is supported by the legs 102. The seat 106 is formed in a rectangular shape in a plan view that is long in the left-right direction and short in the front-to-rear direction. The backrest 109 is formed to extend upward from the rear end of the seat 106.

[0062] The seat 106 includes an outer cover 132, a cushion 131 (see FIG. 12) covered with the outer cover 132, padding (not shown) interposed between the cushion 131 and the outer cover 132, and a seat plate (not shown) supporting the cushion 131 from below. The cushion 131 is formed of a net-like structure made of a thermoplastic resin, similar to the cushion 31 of the first embodiment. The cushion 131 has a distribution of hardness.

[0063] The hardness of the cushion 131 will be described with reference to FIG. 12. FIG. 12 is a diagram showing the distribution of hardness on the upper surface 131b of the cushion 131 according to the second embodiment. In this embodiment, the distribution of hardness on the upper surface 131b of the cushion 131 is symmetrical. Each region on the upper surface 131b of the cushion 131 is defined as follows according to the distribution of hardness on the upper surface 131b. In this embodiment, the regions described below are separated from each other by a boundary line that extends linearly in the left-right direction in a plan view. The upper surface 131b of the cushion 131 includes a first region R1, a second region R2, and a third region R3.

[0064] Each first region R1 is a region that supports the buttocks of a seated occupant. All points in the first region R1 support the buttocks of a seated occupant. The first region R1 is located inside (rearward) of the front edge of the upper surface 131b of the cushion 131. The first region R1 has a constant width in the front-to-rear direction and extends in the left-to-right direction over the entire length of the upper surface 131b of the cushion 131. The first region R1 includes the center of the upper surface 131b of the cushion 131 in the front-to-rear direction.

[0065] The second region R2 is adjacent to the outside of the first region R1 in a plan view. The second region R2 is located inside (rear) the front edge of the upper surface 131b of the cushion 131. The second region R2 is adjacent to the entire first region R1 in front. The second region R2 has a constant width in the front-rear direction and extends in the left-right direction over the entire length of the upper surface 131b of the cushion 131.

[0066] The third region R3 is adjacent to the outside of the second region R2 in a plan view. The third region R3 is located on the opposite side of the pair of first regions R1 with the second region R2 in between. The third region R3 is located on the inner side (rear) of the front edge of the upper surface 131b of the cushion 131. The third region R3 is adjacent to the entire second region R2 in front. The third region R3 has a constant width in the front-rear direction and extends in the left-right direction over the entire length of the upper surface 131b of the cushion 131.

[0067] The hardness of the first region R1, the second region R2, and the third region R3 is set as follows. Here, a first virtual half line L1, a first location P1, a second location P2, and a third location P3 are defined. The first location P1 is an arbitrary point in the first region R1. The first virtual half line L1 extends outward from the first location P1 in a plan view, and passes through the first region R1, the second region R2, and the third region R3 in succession. In this embodiment, the first virtual half line L1 extends from the first location P1 of the first region R1 in a direction inclined forward with respect to the left-right direction due to the above-mentioned positional relationship of the first region R1, the second region R2, and the third region R3. In FIG. 12, as an example of the first virtual half line L1, the first virtual half line L1 extending forward from the first location P1 is shown. The second location P2 is an arbitrary point on the first virtual half line L1 in the second region R2. The third point P3 is an arbitrary point on the first imaginary half line L1 in the third region R3. That is, the second point P2 is located forward of the first point P1, and the third point P3 is located forward of the second point P2. The first point P1 has a first hardness. The second point P2 has a second hardness. The second hardness is higher than the first hardness. The third point P3 has a third hardness. The third hardness is higher than the second hardness.

[0068] The first region R1 may have a uniform hardness throughout, or may have a distribution of hardness. For example, the first region R1 may have a distribution of hardness that is periodic in the left-right direction according to the maximum number of people that can sit on the chair 101. The second region R2 and the third region R3 are similar to the first region R1. In this embodiment, the hardness of all points in the second region R2 is higher than the hardness of the first region R1. The third region R3 is similar to the second region R2.

[0069] Since the first location P1, the second location P2, and the third location P3 are arranged as described above, the cushion 131 has the following configuration: The cushion 131 has a first hardness at a position where the buttocks of a seated person come into contact, a second hardness outside the first hardness, and a third hardness outside the second hardness.

[0070] The upper surface 131b of the cushion 131 further includes a fifth region R5.

[0071] The fifth region R5 supports the front of the thighs of a seated person. The fifth region R5 is located in front of the first region R1 in a plan view. The fifth region R5 includes the front edge of the upper surface 131b of the cushion 131. That is, the fifth region R5 is adjacent to the third region R3 in front. The fifth region R5 extends in the left-right direction. The hardness of the fifth region R5 is set as follows. Here, the fifth point P5 is defined in relation to the above-mentioned first point P1. The fifth point P5 is an arbitrary point on the third imaginary half line L3 that extends forward from the first point P1 in a plan view and passes through the first region R1 and the fifth region R5 continuously in the fifth region R5. The fifth point P5 has a fifth hardness. The fifth hardness is equal to or less than the first hardness. In this embodiment, the hardness of the entire fifth region R5 is equal to or less than the first hardness. Since the fifth region R5 is disposed relative to the first region R1 as described above, the cushion 131 has a hardness equal to or less than the first hardness in front of the position where the buttocks of a seated person come into contact.

[0072] As described above, the seat 106 of the chair 101 of this embodiment has the cushion 131 formed of a net-like structure made of thermoplastic resin, and therefore has the same effects as the first embodiment. In addition, in this embodiment, the buttocks of the seated person are wrapped from the front. Therefore, when sitting, the buttocks are less likely to slip outward, and the person sits in a stable state. Therefore, a chair 101 that is comfortable to sit on is obtained.

[0073] Furthermore, the cushion 131 further has a fifth point P5 located in front of the first point P1 and having a hardness equal to or less than the first hardness. With this configuration, the fifth point P5 with which the thighs of the seated person come into contact is set to a hardness equal to or less than the first hardness, so that the thighs of the seated person come into contact with the parts of the cushion 131 with a lower hardness. This reduces the feeling of pressure on the thighs. This further improves the sitting comfort.

[0074] In the illustrated example, the entire first region R1 is spaced from the rear edge of the upper surface 131b of the cushion 131 in the front-rear direction. In this case, it is desirable that the region between the first region R1 and the rear edge of the upper surface 131b of the cushion 131 has the second hardness. This limits the change in hardness from the first region R1 toward the rear end of the cushion 131, making it easier for the first region R1 to sink downward.

[0075] In the second embodiment, the fifth region R5 is provided on the upper surface 131b of the cushion 131, but the present invention is not limited to this configuration. As shown in Fig. 13, the third region R3 may be formed so as to include the front edge of the upper surface 131b of the cushion 131.

[0076] The present invention is not limited to the above-described embodiment explained with reference to the drawings, and various modifications are possible within the technical scope of the present invention. For example, in the above embodiment, the chair has a backrest, but the present invention is not limited to this, and can also be applied to a chair seat that does not have a backrest.

[0077] In the above embodiment, the net-like structure forming the cushion is made of polyethylene, but the raw material of the net-like structure is not limited to this, and any known thermoplastic resin can be used alone or in a mixture of multiple types. Thermoplastic resins that can be used as the raw material of the net-like structure include, for example, polypropylene, polyvinyl chloride, polystyrene, polyester, etc., in addition to polyethylene. By forming the net-like structure from a thermoplastic resin, the cushion after use can be horizontally recycled and reused as the raw material of the net-like structure.

[0078] In the above embodiment, the legs and the seat are separate members, but the present invention is not limited to this configuration. That is, the legs and the seat may be integrally formed. Also, the legs and the seat may be integrally covered by the outer cover.

[0079] In the above embodiment, the padding is interposed between the seat and the cover, but the present invention is not limited to this configuration, that is, the cover may directly cover the seat.

[0080] In the above embodiment, each region on the upper surface of the cushion is divided by a boundary line that extends linearly according to the distribution of hardness. When the cushion is made of urethane foam, the original liquid of multiple types of urethane that are set to have different hardness after hardening is injected into the mold in liquid form, so that the boundary lines between the respective regions after hardening are curved. In contrast, in the cushion of the above embodiment, the boundary lines between the respective regions on the upper surface of the cushion are linear. It is also possible to arrange it so that each region on the upper surface of the cushion is divided by a boundary line that extends in a broken line formed by a number of straight lines with different angles. However, at least a part of the boundary line that divides each region may extend in a curved line.

[0081] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate. [Explanation of symbols]

[0082] 1,101...chair 2,102...legs 6,106...seat 9,109...backrest 30...seat plate 30b...outer edge 31,131...cushion 31a...projection 31b,131b...upper surface 31c...lower surface 32,132...outer cover P1...first location P2...second location P3...third location P5...fifth location (front location) R1...first region R4...central region (fourth region)

Claims

1. A chair having a backrest, a seat and legs, The locus is A cushion formed of a network structure made of a thermoplastic resin; A seat plate supporting the cushion; An outer cover covering the cushion; having The upper surface of the cushion is a first portion having a first hardness and configured to support the buttocks of a seated occupant; a second portion located outside the first portion in a plan view and having a second hardness higher than the first hardness; a third location located outside the second location in a plan view and having a third hardness higher than the second hardness; having chair.

2. The cushion further includes a front portion located forward of the first portion and having a hardness less than or equal to the first hardness.

2. The chair of claim 1.

3. A hardness distribution on the upper surface of the cushion coincides with a hardness distribution on the lower surface of the cushion when viewed from above and below. A chair according to claim 1 or claim 2.

4. The cushion is A pair of first regions including the first location and spaced apart from each other on a center of the upper surface in a left-right direction; a central region located between the pair of first regions and including a central portion in a left-right direction of the upper surface; having The hardness of the central region is greater than the first hardness. A chair according to claim 1 or claim 2.

5. The cushion is disposed along an outer edge of the seat plate and has a protrusion that engages with the outer edge. A chair according to claim 1 or claim 2.

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