Seat, chair

Abstract

This reduces the concentration of pressure on the tips of the ischial tuberosities and the concentration of the seated person's weight on the tips of the thighs. [Solution] A seat comprising a seat body, wherein the seat surface of the seat body has a recess facing the ischial tuberosity of the seated person's buttocks. The recess has an effective opening width of 40 mm or more in the front-to-back direction of the recess, and includes a front support portion positioned in front of the recess and at a higher position than the recess, which supports the portion of the buttocks in front of the ischial tuberosity, and a rear support portion positioned behind the recess and at a higher position than the recess, which supports the portion of the buttocks in rear of the ischial tuberosity.

Description

Technical Field

[0001] The technology disclosed in the present specification relates to a seat part and a chair.

Background Art

[0002] Conventionally, seat parts intended to alleviate the concentration of the seated person's body weight on the tips of the ischial bones (hereinafter referred to as "pressure concentration on the tips of the ischial bones") have been known. A conventional seat part has a pair of recesses arranged side by side in the left-right direction. Each recess is disposed at a position where a portion corresponding to the tip of the ischial bone of the seated person's buttocks rests (refer to Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional seat part, for example, problems arise such as insufficient alleviation of pressure concentration on the tips of the ischial bones, and concentration of the seated person's body weight also on the tip portions of the thighs.

[0005] The present specification discloses a technology capable of solving at least one of the above-described problems. Note that such problems are not limited to the seat part alone, and are common to, for example, chairs and posture correction tools.

Means for Solving the Problems

[0006] The technology disclosed in the present specification can be implemented, for example, in the following forms.

[0007] (1) The seat disclosed herein is a seat comprising a seat body, the seat surface of the seat body comprising: a recess facing the ischial tuberosity of the seated person's buttocks, the recess having an effective opening width in the front-rear direction of 40 mm or more; a front support portion positioned in front of the recess and at a higher position than the recess, supporting the portion of the buttocks in front of the ischial tuberosity; and a rear support portion positioned behind the recess and at a higher position than the recess, supporting the portion of the buttocks in rear of the ischial tuberosity. In this configuration, the effective opening width in the front-rear direction of the recess formed on the seat surface of the seat body is 40 mm or more. Therefore, the recess is positioned where the portion of the seated person's buttocks located directly below the ischial tuberosity (hereinafter referred to as the "ischial tuberosity corresponding portion") is located. The front support portion supports the portion of the buttocks in front of the ischial tuberosity, and the rear support portion supports the portion of the buttocks in rear of the ischial tuberosity. This configuration mitigates the concentration of the seated person's weight on the area corresponding to the ischial tuberosity.

[0008] (2) In the seat portion described above, the recess may be configured to extend continuously in both directions from the left-right center of the seat surface while maintaining an effective opening width of 40 mm or more. According to this configuration, the recess extends continuously in both directions from the left-right center of the seat surface while maintaining an effective opening width of 40 mm or more. Therefore, regardless of the size of the sitter's ischial tuberosities, the portion corresponding to the sitter's ischial tuberosities is positioned in the recess. As a result, this configuration reduces the concentration of the sitter's weight on the portion corresponding to the ischial tuberosities, regardless of the size of the sitter's ischial tuberosities.

[0009] (3) In the seat portion described above, at least one of the front support portion and the rear support portion may be configured as an inclined surface that becomes higher as it moves away from the recess in the front-rear direction. This configuration reduces the concentration of the sitter's weight on the front support portion and the rear support portion compared to a configuration in which the front support portion and the rear support portion have corners.

[0010] (4) In the above-mentioned seat, the seat surface may further include a rear inclined surface that extends diagonally upward and backward from the lowest part of the recess and supports the rear part of the pelvis of the buttocks. With this configuration, the inclined surface that extends diagonally upward and backward from the bottom surface of the recess and supports the rear of the pelvis prevents the sitter's pelvis from moving backward.

[0011] (5) In the above-mentioned seat, the seat surface may further include a front inclined surface that extends diagonally forward and upward from the recess and beyond the front support portion, and supports the base portion of the seated person's thighs. According to this configuration, the front inclined surface supports the base portion of the seated person's thighs and prevents the seated person's weight from concentrating on their thighs.

[0012] (6) The chair described above may be configured to include a chair body that includes the seat body described in (1).

[0013] (7) In the chair described above, the chair body further includes a backrest body having a backrest seat and a support member positioned behind the backrest seat, wherein the support member has a pressing surface that presses against the portion of the back of the backrest seat that is above the center in the vertical direction. With this configuration, the support member presses against the thoracic spine of the sitter and prevents the sitter's chest from tilting backward.

[0014] (8) In the chair described above, the chair body further includes a backrest body and a headrest body having a headrest surface, wherein at least a portion of the headrest surface may be located in front of the backrest surface of the backrest body. With this configuration, at least a portion of the headrest surface of the headrest is located further in front of the backrest surface of the backrest body, thereby supporting the cervical spine of the sitter.

[0015] Note that the technology disclosed in the present specification can be implemented in various forms, and for example, is not limited to a seat part alone, and can be implemented in forms such as a chair provided with the seat part alone, a posture retention tool, a cushion, a sofa, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] [Figure 1] Perspective view showing the configuration of a chair 1 in the present embodiment [Figure 2] Illustrative view showing the cross-sectional configuration of the chair 1 at the position II-II in FIG. 1 [Figure 3] Illustrative view showing the planar configuration of the seat part of the chair 1 in the present embodiment [Figure 4] Illustrative view showing the cross-sectional configuration of a seat part main body 10 at the position IV-IV in FIG. 3 [Figure 5] Illustrative view showing the posture of a human body seated on the seat part main body 10 of the chair 1 of the present embodiment [Figure 6] Illustrative view showing the posture of a human body seated on a seat part main body 10B of a chair of a comparative example [Figure 7] Illustrative view showing the posture of a human body seated on the chair 1 of the present embodiment [Figure 8] Illustrative view showing the posture of a human body seated on a chair 1B of a comparative example [Figure 9] Illustrative view showing the pressure state of the buttocks of a sitter seated on the chair 1 of the present embodiment [Figure 10] Illustrative view showing the pressure state of the buttocks of a sitter seated on the seat part main body 10B of a chair of a comparative example DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0017] A. Embodiment: A-1. Configuration of Chair 1: The present embodiment will be described with reference to FIG. 1 to FIG. 4. Note that each drawing shows mutually orthogonal XYZ axes for specifying directions. The positive Z-axis direction is the upward direction, the negative Z-axis direction is the downward direction, the positive X-axis direction is the forward direction, and the negative X-axis direction is the rearward direction. Further, the positive Y-axis direction is the right direction, and the negative Y-axis direction is the left direction.

[0018] Figure 1 is a perspective view showing the configuration of chair 1 in this embodiment, and Figure 2 is an explanatory diagram showing the cross-sectional configuration of chair 1 at position II-II in Figure 1. In Figure 2, the legs 50 of chair 1, which will be described later, are omitted. Chair 1 is a so-called work chair (office chair) and is used, for example, in homes, offices, shops, hotels, public facilities, etc. The height of chair 1 to the seat surface is, for example, 380 mm or more and 520 mm or less (more specifically about 470 mm), the width of chair 1 in the left-right direction is, for example, 460 mm or more and 642 mm or less (more specifically about 515 mm), and the depth of chair 1 in the front-back direction is, for example, 410 mm or more and 700 mm or less (more specifically about 620 mm).

[0019] Chair 1 comprises a chair body that constitutes the frame of the chair 1. In this embodiment, chair 1 does not have cushions or the like, and the chair body is exposed to the outside. As shown in Figure 1, the chair body comprises a seat body 10, a backrest body 20, a headrest body 30, and legs 50.

[0020] (Seat body 10) Figure 3 is an explanatory diagram showing the planar configuration of the seat body 10, and Figure 4 is an explanatory diagram showing the cross-sectional configuration of the seat body 10 at position IV-IV in Figure 3. Figure 4 shows the cross-sectional configuration of the seat body 10 in an XZ section (hereinafter referred to as the "longitudinal section") perpendicular to the left-right direction. The seat body 10 is the part that mainly supports the buttocks of the seated person V. The seat body 10 is generally flat, and as shown in Figure 3, the shape of the seat body 10 when viewed in the vertical direction is generally rectangular. The seat surface 10S of the seat body 10 includes a recess 110, a rear inclined surface 122S, a front inclined surface 132S, a front end surface 134S, and a rear end surface 140S. The rear inclined surface 122S is an example of an inclined surface. The recess 110 has a bottom surface 112S, a rear side surface 114S, and a front side surface 116S. Note that the front inclined surface 132S is an example of a front support section. The rear inclined surface 122S (center inclined surface 122Sa) is an example of a rear support section.

[0021] The recess 110 is the part of the seated person V's buttocks that is directly below the ischial tuberosity T (hereinafter referred to as the "ischial tuberosity corresponding part"). The recess 110 is located behind the center position O of the seat surface 10S (the center position of the longest part of the seat surface 10S in the front-to-back direction) in the front-to-back direction (X-axis direction) (see Figure 3). The shape of the recess 110 is a band that extends along the left-to-right direction. The recess 110 extends continuously and linearly in both the left-to-right direction from the center position O of the seat surface 10S. The width (total length in the left-to-right direction) L110 of the recess 110 (see Figure 3) is, for example, 200 mm. The width of the recess 110 in the front-to-back direction (upper end opening width W110, lower end opening width W112) is approximately the same along the entire length of the recess 110. The upper end opening width W110 of the recess 110 in the front-to-back direction (see Figure 4) is, for example, 70 mm. The lower end opening width W112 of the recess 110 in the front-to-back direction (width of the bottom surface 112S in the front-to-back direction, see Figure 4) is, for example, 70 mm. The shape of both ends of the recess 110 in the left-to-right direction is an arc-shaped projection.

[0022] The width L110 of the recess 110 may be 80 mm or more and 500 mm or less, 100 mm or more and 300 mm or less, or 150 mm or more and 200 mm or less.

[0023] The bottom surface 112S is, for example, a flat surface aligned horizontally and is located at the lowest position of the seat surface 10S (see Figure 4). The width of the bottom surface 112S in the left-right direction is approximately the same as the width L110 of the recess 110.

[0024] The rear side surface 114S is the rearmost surface of the recess 110. The rear side surface 114S is an inclined surface that extends diagonally upward and backward from the rear end of the bottom surface 112S. The rear side surface 114S is a plane that extends linearly diagonally upward and backward. The inclination angle α12 of the rear side surface 114S with respect to the horizontal direction is greater than the inclination angle α13 of the front inclined surface 132S with respect to the horizontal direction. Specifically, the inclination angle α12 of the rear side surface 114S is approximately 40°. The inclination angle α12 may be 20° or more and 60° or less, 30° or more and 45° or less, or 30° or more and 40° or less.

[0025] The front side surface 116S is the surface located in front of the recess 110. The front side surface 116S is a plane aligned in the vertical direction.

[0026] The recess 110 has an effective opening width which is the narrowest width in the front-to-back direction. For example, the rear side surface 114S and the front side surface 116S face each other in the front-to-back direction of the seat body 10. The rear side surface 114S and the front side surface 116S form the opening of the recess 110 horizontally in the front-to-back direction of the seat body 10. In the horizontal direction of the chair 1, the effective opening width is the width of the shortest point in the front-to-back direction between the rear side surface 114S and the front side surface 116S. The lower end opening width W112 of the recess 110 (the width of the bottom surface 112S in the front-to-back direction) is an example of the effective opening width.

[0027] The upper end opening width W110 of the recess 110 is the horizontal width between the upper end of the rear side surface 114S and the upper end of the front side surface 116S. The front-to-back width of the bottom surface 112S, which is the lower end opening width W112 of the recess 110, is the same as the horizontal width between the lower end of the rear side surface 114S and the lower end of the front side surface 116S. The upper end opening width W110 should be 40 mm or more. The upper end opening width W110 may be 40 mm or more and 100 mm or less, or 45 mm or more and 80 mm or less. The lower end opening width W112 should be 40 mm or more. The lower end opening width W112 may be 40 mm or more and 100 mm or less, or 45 mm or more and 80 mm or less. The upper end opening width W110 is greater than or equal to the lower end opening width W112.

[0028] The rear inclined surface 122S supports the rear and left and right sides of the ischial tuberosities of the seated person V's buttocks. The rear inclined surface 122S is positioned to surround the rear and left and right sides of the recess 110. Specifically, the rear inclined surface 122S includes a center inclined surface 122Sa and a pair of side inclined surfaces 122Sb. The center inclined surface 122Sa is positioned directly behind the recess 110. The center inclined surface 122Sa is on the same plane as the rear side surface 114S without any step difference. The center inclined surface 122Sa is a plane that extends linearly upward and diagonally backward. The inclination angle of the center inclined surface 122Sa with respect to the horizontal direction is the same as the inclination angle α12 of the rear side surface 114S. The height h12 from the bottom surface 112S to the upper end 122P of the center inclined surface 122Sa is higher than the height (for example, height h13) from the bottom surface 112S to either the front inclined surface 132S or the front end surface 134S. The boundary between the center inclined surface 122Sa and the rear side surface 114S is, for example, at the same position as the upper end of the front side surface 116S in the vertical direction of the chair 1.

[0029] The height h12 from the base surface 112S to the upper end 122P of the center inclined surface 122Sa is, for example, approximately 70 mm. Note that the height h12 may be 5 mm or more, 20 mm or more and 150 mm or less, or 40 mm or more and 70 mm or less. Also, the length in the front-to-back direction from the base surface 112S to the upper end 122P of the center inclined surface 122Sa is, for example, approximately 90 mm. This length may be 15 mm or more, 30 mm or more and 150 mm or more, or 65 mm or more and 135 mm or less.

[0030] A pair of side inclined surfaces 122Sb are positioned on each of the left-right sides of the recess 110. Each side inclined surface 122Sb is adjacent to the center inclined surface 122Sa in the circumferential direction of the recess 110. Each side inclined surface 122Sb is an inclined surface that extends diagonally upward and backward and to the left and right from the recess 110 toward the rear end surface 140S. In a vertical view, the shape of each side inclined surface 122Sb has an outer shape that curves in an arc, approaching the front end (front inclined surface 132S) of the seat surface 10S (front inclined surface 132S) as it approaches the left-right end of the seat surface 10S (front inclined surface 132S) from the upper end 122P of the center inclined surface 122Sa.

[0031] The front inclined surface 132S is the part that supports the front of the ischial tuberosities of the seated person V's buttocks. The front inclined surface 132S is the part where the base of the seated person V's thighs is positioned. The front inclined surface 132S is located on the front side of the recess 110. The rear end of the front inclined surface 132S and the upper end of the front side surface 116S are adjacent. In the vertical direction, the shape of the front inclined surface 132S is elongated (rectangular) in the left-right direction of the seat surface 10S, and each of the left and right ends of the front inclined surface 132S extends to the left and right ends of the seat surface 10S. The rear end of the front inclined surface 132S is located higher than the front end of the bottom surface 112S of the recess 110. The step difference D110 (depth of the recess 110) between the rear end of the front inclined surface 132S and the front end of the bottom surface 112S is, for example, 12 mm. The step height D110 only needs to be 5mm or more; for example, it can be 7mm or more and 25mm or less, or 10mm or more and 20mm or less.

[0032] The front inclined surface 132S is an inclined surface that extends diagonally upward and forward from the rear end of the front inclined surface 132S. The front inclined surface 132S is a plane that extends linearly diagonally upward and forward. As described above, the inclination angle α13 of the front inclined surface 132S is smaller than the inclination angle α12 of the center inclined surface 122Sa. Also, the height h13 of the front inclined surface 132S is lower than the height h12.

[0033] The inclination angle α13 of the front inclined surface 132S is, for example, 4°. The inclination angle α13 may be, for example, 1.5° or more and 30° or less, or 2° or more and 15° or less. Also, if the inclination angle α13 is 1, the inclination angle α12 is 10. It may be greater than 1, for example, greater than 1 and 35 or less, or 1.3 or more and 30 or less, or 3 or more and 20 or less. Also, the ratio of inclination angle α13:inclination angle α12 is 4:40. The ratio of inclination angle α13:inclination angle α12 may be 1.5 or more and 30 or less: 20 or more and 50 or less, or 2 or more and 30 or less: 30 or more and 40 or less. The height h13 of the front inclined surface 132S is, for example, approximately 15 mm. The height h13 may be, for example, 5 mm or more and 25 mm or less, or 5 mm or more and 15 mm or less.

[0034] The front end surface 134S is the portion that includes the front end of the seat surface 10S and is the portion where the front part of the thighs of the seated person V is positioned. The front end surface 134S is positioned in front of the front inclined surface 132S. The rear end of the front end surface 134S is adjacent to the front end of the front inclined surface 132S. In the vertical direction, the shape of the front end surface 134S is elongated (rectangular) in the left-right direction of the seat surface 10S, and each of the left and right ends of the front end surface 134S extends to the left and right ends of the seat surface 10S. The inclination angle of the front end surface 134S with respect to the horizontal direction is preferably smaller than the inclination angle α13 of the front inclined surface 132S with respect to the horizontal direction. In Figure 4, etc., a configuration is shown in which the front end surface 134S is a plane aligned with the horizontal direction. In a vertical view, the length of the front end surface 134S in the front-rear direction is preferably shorter than the length of the front inclined surface 132S in the front-rear direction (see Figure 3).

[0035] The rear end surface 140S is the portion that includes the rear end of the seat surface 10S. The rear end surface 140S is positioned to surround the rear outer circumference of the rear inclined surface 122S. When viewed in the front-rear direction, the shape of the rear end surface 140S has an arc-shaped outer shape that slopes downward as it approaches both ends of the seat surface 10S in the left-right direction.

[0036] (Backrest main body 20) The backrest body 20 is primarily the part that supports the back of the seated person V. As shown in Figure 1, the backrest body 20 is generally flat. When viewed from the front of the chair 1, the backrest body 20 is roughly rectangular. As shown in Figure 2, the backrest body 20 extends in the vertical direction of the chair 1. The front surface of the backrest body 20 is the backrest surface 20S. As shown in Figure 2, the backrest surface 20S is a surface that curves forward in the vertical direction. The front end portion 20P of the backrest surface 20S extends in the left-right direction of the chair 1. The front end portion 20P of the backrest surface 20S is located below the backrest body 20 in the vertical direction. The front end portion 20P of the backrest surface 20S is located on the rear inclined surface 122S in the vertical direction.

[0037] With respect to the vertical direction of chair 1, the height h20 of the upper end of the backrest body 20 is, for example, approximately 540 mm from the upper end of the recess 110. The height h20 may be between 400 mm and 700 mm. The height h40 of the lower end of the backrest body 20 is, for example, approximately 150 mm from the upper end of the recess 110. The height h40 may be between 80 mm and 300 mm, or between 135 mm and 165 mm. The height h24 of the front end portion 20P of the backrest surface 20S is, for example, approximately 230 mm from the upper end of the recess 110. The height h24 may be between 170 mm and 280 mm.

[0038] The backrest body 20 includes a backrest sheet 22 and a support member 24. The backrest sheet 22 is located in front of the backrest body 20. The backrest sheet 22 is a member that forms the backrest surface 20S.

[0039] The support member 24 is positioned behind the main body 20 of the backrest. The pressing surface 24S, which is the front of the support member 24, is in contact with a part of the back of the backrest seat 22. The support member 24 presses the backrest seat 22 from the rear. As a result, the backrest seat 22 protrudes forward of the chair 1. The backrest seat 22 may be a mesh-like sheet or a sheet without a mesh.

[0040] The support member 24 is a member that curves forward relative to the vertical direction of the chair 1. The support member 24 extends in the left-right direction. The front end portion 24P of the support member 24 extends in the left-right direction. The front end portion 24P of the support member 24 coincides with the front end portion 20P of the backrest surface 20S. The upper end of the support member 24 is in contact with the surface of the backrest seat 22 above the midpoint in the vertical direction. The height h22 of the upper end of the support member 24 is, for example, approximately 435 mm from the upper end of the recess 110. The height h24 may be 350 mm or more and 550 mm or less.

[0041] Furthermore, with respect to the front-to-back direction of chair 1, the reference line CL is defined as a line perpendicular to the horizontal direction of chair 1, with respect to a point 90 mm from the rear end of the center inclined surface 122Sa. The front end portion 20P (front end portion 24P) of the backrest surface 20S is located in front of the reference line CL.

[0042] Chair 1 has a pair of connecting members J below the backrest body 20 (see Figure 1). The connecting members J connect the lower part of the backrest body 20 to the seat body 10 in the vertical direction of chair 1. The pair of connecting members J are arranged in the left-right direction of the seat body 10. A space R is formed between the pair of connecting members J.

[0043] Space R is the portion that accommodates the rear portion of the seated person V's buttocks. In the vertical direction, space R is formed between the upper end 122P of the rear inclined surface 122S of the seat body 10 and the lower end of the backrest body 20, which will be described later. In the front-rear direction, space R is formed from the front end portion 20P of the backrest body 20 to the rear. The vertical height hR of space R is, for example, 80 mm. Note that the height hR may be 35 mm or more and 125 mm or less, or 65 mm or more and 95 mm or less. The front-rear width WR of space R (distance from the front end portion 20P of the backrest body 20 to the rear end portion of the backrest body 20) is, for example, 75 mm. The width WR may be 0 mm or more and 200 mm or less.

[0044] (Headrest main body 30) The headrest body 30 is the part that supports the head of the seated person V. As shown in Figure 1, the headrest body 30 is generally flat. The headrest body 30 is generally rectangular in shape when viewed from the front of the chair 1. The front surface of the headrest body 30 is the headrest surface 30S. As shown in Figure 2, the headrest surface 30S is a surface that curves forward in the vertical direction. The front end portion 30P of the headrest body 30 extends in the left-right direction of the chair 1. The front end portion 30P of the headrest body 30 is located below the headrest body 30 in the vertical direction. The front end portion 30P of the headrest body 30 is located on the rear inclined surface 122S in the vertical direction. In any cross-section in the vertical direction of the chair 1, the front end portion 30P of the headrest body 30 is located, for example, in front of the front end portion 20P. Furthermore, with respect to the front-to-back direction of chair 1, the front end portion 30P of the headrest body 30 is positioned in front of the reference line CL. The headrest body 30 is movable in the vertical direction.

[0045] (legs 50) The leg section 50 has multiple leg frames 52. These multiple leg frames 52 form the base that supports the seat body 10 and have multiple frames arranged radially. Casters 54 are provided at the end of each frame.

[0046] A-2. Effects of this embodiment: In the chair 1 of this embodiment, the effective opening width (lower end opening width W112) in the front-to-back direction of the recess 110 formed in the seat surface 10S of the seat body 10 is 40 mm or more. Therefore, the recess 110 is positioned where the part of the seated person V's buttocks located directly below the ischial tuberosity T (see Figure 5 described later) is located (hereinafter referred to as the "ischial tuberosity corresponding part"). The front support part (front inclined surface 132S) supports the part of the buttocks in front of the ischial tuberosity T (thigh), and the rear support part (center inclined surface 122Sa) supports the part of the buttocks in rear of the ischial tuberosity T. This configuration mitigates the concentration of the seated person V's weight on the ischial tuberosity corresponding part. A detailed explanation follows below.

[0047] Figure 5 is an explanatory diagram showing the posture of a person seated on the seat body 10 of chair 1 in this embodiment, and Figure 6 is an explanatory diagram showing the posture of a person seated on the seat body 10B of the chair in the comparative example. The seat body 10B of the chair in the comparative example differs from the seat body 10 of chair 1 in this embodiment in that the effective opening width (lower end opening width W112B) of the recess 110B is 25 mm. Note that the backrest body 20 and the headrest body 30 are omitted in Figures 5 and 6.

[0048] The anterior-posterior width of the ischial tuberosity T varies from person to person, but is generally between 20 mm and 30 mm. In the comparative example, the effective opening width of the recess 110B is 25 mm, which is roughly sufficient to accommodate the ischial tuberosity T of a seated person V. However, the inventors have newly discovered that when the effective opening width of the recess is approximately the same width as the ischial tuberosity T, the portion corresponding to the ischial tuberosity abuts against the inner wall surface of the recess (see Figure 6), and therefore the concentration of the seated person V's weight on the portion corresponding to the ischial tuberosity cannot be sufficiently mitigated.

[0049] In contrast, in this embodiment, the lower end opening width W112 of the recess 110 is 40 mm or more. Therefore, the ischial tuberosity-corresponding portion is prevented from coming into contact with the inner wall surface or the like that makes up the recess 110. In this embodiment, the front inclined surface 132S located on the front side of the recess 110 supports the base portion of the thigh of the seated person V, and the center inclined surface 122Sa located on the rear side of the recess 110 supports the rear portion of the buttocks of the seated person V. As a result, the contact pressure between the inner wall surface (bottom surface 112S, etc.) of the recess 110 and the ischial tuberosity-corresponding portion is reduced (see Figure 5). For example, the center inclined surface 122Sa (pelvic upright inclination) causes the buttocks of the seated person V to slide forward relative to the seat surface 10S. As a result, the pressure on the ischial tuberosity T is distributed to the more distal part of the thigh, and the pressure on the ischial tuberosity T is reduced. The anterior inclined surface 132S provides support to the base of the seated person's thighs, with the muscles surrounding the ischial tuberosity T acting like a hammock, thus suspending the ischial tuberosity T.

[0050] Furthermore, in this embodiment, both the front inclined surface 132S and the center inclined surface 122Sa are inclined surfaces that become higher as they move away from the recess 110 in the front-rear direction. Therefore, this embodiment mitigates the concentration of the seated person V's weight on the front and rear support parts, compared to, for example, a configuration in which the front and rear support parts have corners. Note that both the front inclined surface 132S and the center inclined surface 122Sa may be flat or curved. When the seated person V sits on the seat body 10, the center inclined surface 122Sa (pelvic upright inclination) distributes the seated person V's weight forward. On the other hand, the front inclined surface 132S suppresses excessive forward distribution of the seated person V's weight. As a result, the center inclined surface 122Sa and the front inclined surface 132S optimally position the seated person V's ischial tuberosity T. For example, the central inclined surface 122Sa (pelvic upright inclination) causes the seated person V's buttocks to slide forward relative to the seat surface 10S. As a result, the pressure on the seated person V's ischial tuberosities T may be distributed to the distal part of the thigh and concentrated on the tip of the thigh that is in contact with the seat surface 10S. Therefore, by having a front inclined surface 132S on the seat body 10, it is expected that the pressure will be returned to the ischial tuberosities T.

[0051] In this embodiment, the recess 110 extends continuously in both the left and right directions from the center position O of the seat surface in the left-right direction, while maintaining an effective opening width of 40 mm or more (see Figure 3). The width L110 of the recess 110 is, for example, 80 mm or more. Therefore, regardless of the size of the seated person V's ischial tuberosities, the portion corresponding to the seated person V's ischial tuberosities is positioned in the recess 110. As a result, this embodiment mitigates the concentration of the seated person V's weight on the portion corresponding to the ischial tuberosities, regardless of the size of the seated person V's ischial tuberosities.

[0052] In this embodiment, the center inclined surface 122Sa extends diagonally backward and upward from the portion supporting the ischial tuberosity of the seated person V (the lowest point of the contact area between the seated person V's buttocks and the center inclined surface 122Sa), and supports the posterior portion of the pelvis P of the buttocks (see Figure 5). Therefore, the center inclined surface 122Sa supports the seated person V's pelvis P in an upright position. The center inclined surface 122Sa also positions the seated person V's lumbar vertebrae L forward. For example, by tilting the seated person V's pelvis P forward, the center inclined surface 122Sa makes the pelvis P upright, and the seated person V's spine forms an S-curve (an S-shaped posture).

[0053] In this embodiment, the front inclined surface 132S extends diagonally forward and upward from the portion supporting the ischial tuberosity of the seated person V (the lowest point of the contact area between the seated person V's buttocks and the front inclined surface 132S), and supports the base portion of the seated person V's thighs (see Figure 5). According to this embodiment, the front inclined surface 132S prevents the seated person V's weight from concentrating on the base portion of their thighs. In addition, the front inclined surface 132S prevents the seated person V's pelvis P from moving forward. In this embodiment, the seat surface 10S has a front end surface 134S in front of the front inclined surface 132S, and the front end surface 134S is inclined more gently than the front inclined surface 132S. Therefore, it prevents the seated person V's weight from concentrating on the tip of their thighs. Furthermore, when viewed from above, the front-to-back width of the front end surface 134S may be 1 / 2 or more, or 2 / 3 or more, of the front-to-back width of the front inclined surface 132S.

[0054] Figure 7 is an explanatory diagram showing the posture of a person seated in chair 1 of this embodiment, and Figure 8 is an explanatory diagram showing the posture of a person seated in chair 1B of the comparative example. Chair 1B of the comparative example differs from chair 1 of this embodiment in that the seat surface 10CS of the seat body 10C is flat (i.e., it does not have a recess 110, a rear inclined surface 122S, a front inclined surface 132S, a front end surface 134S, and a rear end surface 140S), and does not have a member to support the thoracic vertebrae B of the person seated V.

[0055] As shown in Figure 8, the comparative example chair 1B does not support the thoracic vertebrae B. As a result, the sitter V's upper body is bent backward, and their head is bent even further backward. Therefore, when sitter V is doing desk work, they have to raise their upper body and neck on their own, which can result in fatigue in the lower back and neck.

[0056] In contrast, as shown in Figure 7, in this embodiment, the chair 1 has a support member 24. The support member 24 has a pressing surface 24S that presses on the upper part of the back of the backrest seat 22, above the vertical center. The support member 24 supports the thoracic vertebrae B of the seated person V via the backrest seat 22, and prevents the seated person V's upper body (chest) from tilting backward. In this embodiment, the pressing surface 24S of the support member 24 is a curved surface that not only presses on the thoracic vertebrae B but also on the lumbar vertebrae L. Therefore, the backrest body 20 can support both the lumbar and chest of the seated person V. The backrest surface 20S of the chair 1 is shaped to follow the curve of the seated person V's spine in the vertical direction of the chair 1. The chair 1 supports the seated person V's spine so that it forms a correct S-curve.

[0057] In this embodiment, in the front-to-back direction, the headrest surface 30S of the headrest body 30 substantially coincides with the curve of the sitter V's cervical spine C in the vertical direction of the chair 1. Therefore, the headrest body 30 supports the sitter V's neck (cervical spine C) to be upright. For example, the headrest surface 30S of the chair 1 is shaped to follow the lordotic curve of the sitter V's cervical spine C in the vertical direction of the chair 1. The chair 1 supports the sitter V's spine so that it forms a correct S-shaped curve.

[0058] Figure 9 is an explanatory diagram showing the pressure state on the buttocks of a person seated on chair 1 of this embodiment, and Figure 10 is an explanatory diagram showing the pressure state on the buttocks of a person seated on the seat body 10B of the chair of the comparative example. The concentration distribution in each figure indicates the level of pressure, with higher concentrations indicating higher pressure. As shown in Figure 10, in the comparative example, it can be seen that the weight of the seated person V is concentrated on the area corresponding to the ischial tuberosity. On the other hand, as shown in Figure 9, in this embodiment, the weight of the seated person V is also distributed to the thighs, and it can be seen that the concentration of pressure on the area corresponding to the ischial tuberosity is alleviated. Moreover, it can be seen that the pressure on the thighs is also distributed.

[0059] B. Variations: The technology disclosed herein is not limited to the embodiments described above and can be modified in various forms without departing from its essence, for example, the following modifications are possible. The configuration of chair 1 in the above embodiment is merely an example and can be modified in various ways.

[0060] The shape, dimensions, and manufacturing method of the chair 1 and the chair body in the above embodiment are merely examples and can be modified in various ways. The shape, dimensions, materials, and manufacturing methods of each part of the chair 1 are merely examples and can be modified in various ways.

[0061] In the above embodiment, the chair 1 consisted of a chair body and did not have cushion members or covers (hereinafter referred to as "cushion members, etc."), but it is not limited to this configuration, and may also consist of a chair body and cushion members, etc. For example, the seat may consist of a seat body and a cushion member that covers the seat surface of the seat body. The backrest may consist of a backrest body and a cushion member that covers the backrest surface of the backrest body. The headrest may consist of a headrest body and a cushion member that covers the headrest surface of the headrest body. The cushion members are made of a material that is more flexible than the chair body.

[0062] In the above embodiment, the bottom surface 112S of the recess 110 is a flat surface aligned horizontally, but it is not particularly limited as long as the upper end opening width W110, the lower end opening width W112, and the step D110 are set appropriately. For example, the bottom surface 112S of the recess 110 may be recessed further downward from the bottom surface 112S. Also, although the bottom surface 112S of the recess 110 is a flat surface, it may be a concave surface or a convex surface. Furthermore, there may be no bottom surface 112S, and the recess 110 may penetrate to the bottom of the seat body 10.

[0063] In the above embodiment, the rear side surface 114S is a plane extending linearly upward and diagonally backward, but it may also be a curved surface protruding in the vertical direction. In the above embodiment, the inclination angle α12 of the rear side surface 114S is the same as the inclination angle of the rear inclined surface 122S (center inclined surface 122Sa), but it does not have to be the same. The inclination angle α12 of the rear side surface 114S may be 10° or more and 90° or less, 20° or more and 60° or less, 30° or more and 45° or less, or 30° or more and 40° or less. The inclination angle of the rear inclined surface 122S (center inclined surface 122Sa) may be 20° or more and 60° or less, 30° or more and 45° or less, or 30° or more and 40° or less.

[0064] In the above embodiment, the front side surface 116S is a plane aligned with the vertical direction, but it may also be a plane extending linearly upward and diagonally backward, or a curved surface protruding in the vertical direction.

[0065] In the above embodiment, the front inclined surface 132S is a plane that extends linearly upward and diagonally forward, but it is not limited to this shape. Specifically, the front inclined surface 132S may be a surface in which the inclination angle of the front inclined surface 132S decreases as it moves from the upper end of the front side surface 116S toward the front of the seat body 10 (towards the front end surface 134S).

[0066] In the above embodiment, the front end surface 134S is a plane aligned horizontally, but it is not limited to this shape. For example, the front end surface 134S may be a plane extending linearly downward and diagonally forward from the rear end (the joint with the front inclined surface 132S). Alternatively, the front end surface 134S may be a curved surface such that the inclination angle of the front end surface 134S with respect to the horizontal gradually decreases as it moves towards the front of the seat body 10.

[0067] In the above embodiment, the front end portion 30P of the headrest body 30 is located on the rear inclined surface 122S in the vertical direction, but the position of the front end portion 30P of the headrest body 30 is not limited to this position.

[0068] In the above embodiment, a chair 1 comprising a seat body 10, a backrest body 20, and a headrest body 30 was used as an example. However, the invention is not limited to a chair, as long as it has any of the features of the seat body 10, the backrest body 20, or the headrest body 30. For example, a posture support device, cushion, sofa, etc., may have a structure that has the features of the above embodiment.

[0069] The technology disclosed herein may also have a configuration comprising at least one of the following configurations (a) to (f). • Configuration (a): A seat comprising a seat body, wherein the seat surface of the seat body has a recess (for example, a pair of recesses arranged in the left-right direction) that faces the ischial tuberosities of the seated person's buttocks, and the recess has an effective opening width of 40 mm or more in the front-back direction. • Configuration (b): A seat comprising a seat body, wherein the seat surface of the seat body has a recess facing the ischial tuberosity of the seated person's buttocks, and the recess extends continuously in both directions from the center in the left-right direction. • Configuration (c): A seat comprising a seat body, wherein the seat surface of the seat body has a recess facing the ischial tuberosity of the seated person's buttocks (for example, a pair of chair recesses arranged in the left-right direction), and a rearward inclined surface extending diagonally upward and backward from the rear side surface constituting the recess, supporting the posterior portion of the pelvis of the buttocks. The rear side surface may extend to a position higher than the upper end of the front side surface constituting the recess. The inclination angle of the front side surface may be greater than the inclination angle of the rear side surface. • Configuration (d): A seat comprising a seat body, wherein the seat surface of the seat body includes a recess facing the ischial tuberosity of the seated person's buttocks (for example, a pair of chair recesses arranged in the left-right direction), and a front inclined surface located in front of the recess and extending diagonally forward upward, supporting the base portion of the seated person's thighs. The seat surface may have a front end surface (a surface including the front end of the seat surface) located in front of the front inclined surface and having a gentler inclination angle than the front inclined surface. • Configuration (e): A chair, the chair body including a backrest body having a backrest seat and a support member positioned behind the backrest seat, the support member having an opposing surface (which may be a pressing surface that presses against the upper part) facing the portion of the back of the back of the backrest seat that is above the vertical center. The opposing surface is spaced apart from the backrest seat and may be positioned to press against the sitter's chest from behind when the sitter leans back against the backrest seat. In configurations where the chair body includes a headrest, the opposing surface may extend to a position on the back of the back of the backrest seat closer to the headrest. The shape of the opposing surface (shape of the central part in the left-right direction) is curved forward when viewed from the left-right direction, and the front end of the opposing surface (the apex of the curved surface, front end portion 20P) may be located below the vertical center of the backrest seat. The opposing surface (the central portion in the left-right direction) may have an upper inclined surface from the front end to the upper end of the opposing surface, and a lower inclined surface from the front end to the lower end of the opposing surface. The upper inclined surface may be a flat surface or a convex surface projecting forward. The lower inclined surface may be a flat surface or a convex surface projecting forward. The inclination angle of the upper inclined surface with respect to the vertical may be the same as the inclination angle of the lower inclined surface with respect to the vertical, or it may be steep or gentle. The inclination length of the upper inclined surface (length in the inclination direction of the inclined surface) may be longer than the inclination length of the lower inclined surface. ·Configuration (f): A chair, the chair body comprising a backrest body and a headrest body having a headrest surface, wherein at least a portion of the headrest surface may be located in front of the backrest surface of the backrest body. In the front-rear direction, the position of the front end of the headrest surface may be substantially the same as the position of the front end of the backrest surface (the difference in position in the front-rear direction may be within 5 mm or within 3 mm). The shape of the headrest surface (shape of the central part in the left-right direction) may be curved forward when viewed in the left-right direction. The headrest surface (central part in the left-right direction) may have an upper inclined surface from the front end of the opposing surface to the upper end of the opposing surface, and a lower inclined surface from the front end of the opposing surface to the lower end of the opposing surface. The upper inclined surface may be a flat surface, a convex surface protruding forward, or a concave surface recessed backward. The lower inclined surface may be a flat surface, a convex surface protruding forward, or a concave surface recessed backward. In the above embodiment, the upper inclined surface is a concave surface, and the lower inclined surface is a convex or flat surface (see Figure 2). The inclination angle of the upper inclined surface with respect to the vertical may be the same as the inclination angle of the lower inclined surface with respect to the vertical, or it may be steep or gentle. The inclination length of the upper inclined surface (length in the inclined direction of the inclined surface) may be longer than the inclination length of the lower inclined surface. [Explanation of Symbols]

[0070] 1, 1B: Chair 10, 10B, 10C: Seat body 10S, 10CS: Seat surface 12: Tilt angle α 13: Tilt angle α 20, 20B: Backrest body 20P: Front end portion 20S: Backrest surface 22: Backrest seat 24: Support member 24P: Front end portion 24S: Pressure surface 30, 30B: Headrest body 30P: Front end portion 30S: Headrest surface 50: Legs 52: Leg frame 54: Caster 110, 110B: Recess 112S: Bottom surface 114S: Rear side 116S: Front side 122S: Rear tilt surface 122Sa: Center tilt surface 122Sb: Side tilt surface 132S: Front tilt surface 134S: Front end surface 140S: Posterior end surface B: Thoracic vertebrae C: Cervical vertebrae CL: Reference line D110: Step J: Connecting member L110: Lateral width L: Lumbar vertebrae O: Center position P: Pelvis R: Space T: Ichial tuberosity V: Seated person W110: Upper end opening width W112, W112B: Lower end opening width

Claims

1. A seat comprising a seat body, The seat surface of the aforementioned seat body is A recess facing the ischial tuberosity of the seated person's buttocks, the recess having an effective opening width of 40 mm or more in the front-to-back direction, An anterior support portion is positioned in front of the recess and at a higher position than the recess, and supports the portion of the buttocks in front of the ischial tuberosity, It includes a rear support portion that is positioned behind the recess and at a higher position than the recess, and that supports the portion of the buttocks posterior to the ischial tuberosity, Seat area.

2. The seat portion according to claim 1, The recess extends continuously in both the left and right directions from the center of the seat surface in the left-right direction, while maintaining the effective opening width of 40 mm or more. Seat area.

3. A seat according to claim 1 or claim 2, At least one of the front support portion and the rear support portion is an inclined surface that becomes higher as it moves away from the recess in the front-rear direction. Seat area.

4. A seat according to claim 1 or claim 2, The aforementioned seat surface further, It extends diagonally backward and upward from the lowest part of the recess, above the posterior support portion, and includes a posterior inclined surface that supports the posterior portion of the pelvis of the buttocks. Seat area.

5. A seat according to claim 1 or claim 2, The aforementioned seat surface further, It extends diagonally forward and upward from the recess and beyond the front support portion, and includes a front inclined surface that supports the base portion of the seated person's thighs, Seat area.

6. A chair comprising a chair body including the seat body described in claim 1.

7. The chair according to claim 6, The chair body further includes a backrest body having a backrest seat and a support member positioned behind the backrest seat. The support member has a pressing surface that presses against the portion of the back of the backrest seat that is above the center in the vertical direction. chair.

8. A chair according to claim 6 or claim 7, The chair body further includes a backrest body and a headrest body having a headrest surface. At least a portion of the headrest surface is located in front of the backrest surface of the backrest body. chair.

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