Chair

Abstract

To provide a chair for reducing discomfort which a sitting person feels.SOLUTION: A chair 1 comprises: a base 12; and a chair body 3 including a seat frame 120 extending in a front and rear direction and constituting at least a part of a seat 100, and a back frame 123 arranged at a rear end of the seat frame 120, so as to be rotatable around an axis O1 along a right and left direction, extending upward from the seat frame 120, and constituting at least a part of a backrest 101. The base 12 includes: a slider for supporting the seat frame 120 in front of the axial line O1 so as to be movable in the front and rear direction; and a backrest support shaft for supporting the back frame 123 under the axial line O1 so as to be rotatable around an axial line O2 along the right and left direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] For example, Patent Document 1 below discloses a reclining chair having a chair body in which a seat and a backrest are combined as an integral unit, and a support structure that rotatably supports the chair body. In Patent Document 1 below, the front end of the seat is rotatably connected to the support structure. The lower end of the backrest is rotatably connected to the support structure. The seat and backrest are rotatably connected to each other. In the type of chair described in Patent Document 1 below, as the backrest rotates backward relative to the support structure, the backrest rotates relative to the seat and the seat also rotates relative to the support structure. As a result, the front end of the seat is lifted upward, and the backrest is reclined. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-533394 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional chair described above, when the backrest is tilted (reclined) while seated in the chair, the front edge of the seat pushes up the occupant's thighs, which can cause the occupant to feel a sense of compression in their thighs, which can be uncomfortable.

[0005] The present disclosure aims to provide a chair that can reduce the discomfort felt by a seated person. [Means for solving the problem]

[0006] In order to solve the above problems, the present disclosure employs the following aspects. A chair according to one embodiment of the present disclosure comprises a support structure, a chair body having a first member extending in the front-to-rear direction and constituting at least a part of the seat, and a second member rotatably attached to the rear end of the first member about a first axis along the left-to-right direction and extending upward from the first member to form at least a part of the backrest, wherein the support structure comprises a first support portion supporting the first member in front of the first axis so as to be movable in the front-to-rear direction, and a second support portion supporting the second member below the first axis so as to be rotatable about a second axis along the left-to-right direction.

[0007] According to this aspect, as the second member rotates about the second axis relative to the support structure, the second member rotates about the first axis relative to the first member, and the first member slides in the front-to-rear direction relative to the support structure. This makes it possible to suppress up-and-down movement of the first member that accompanies the rearward rotation of the second member, compared to conventional configurations in which the front end of the seat rises as the backrest rotates rearward. In other words, as the second member rotates, the first member can move smoothly in the front-to-rear direction, reducing the discomfort felt by the seat occupant when reclining.

[0008] In the chair of the above aspect, it is preferable that the chair body includes a connecting member that connects the first member and the second member so as to be rotatable about the first axis. According to this aspect, by using a connecting member that is separate from the first member and the second member, it is easy to adjust the amount of rotation of the second member relative to the first member while ensuring the strength of the chair body.

[0009] In the chair of the above aspect, it is preferable that the chair body is configured to be rotatable between a first position where the angle between the first member and the second member about the first axis is a first angle and a second position where the angle between the first member and the second member about the first axis is a second angle smaller than the first angle, the second support part is an axial member extending along the second axis, the second member has an opening that opens toward an intersecting direction intersecting the second axis and into which the second support part can be inserted, and the chair body is provided with a holding part that holds the second support part, and a stopper part that engages with the support structure in the intersecting direction when the chair body is in the first position to restrict movement of the second member relative to the support structure in the intersecting direction, and that disengages from the support structure when the chair body is in the second position to allow movement of the second member relative to the support structure in the intersecting direction. According to this aspect, with the chair body in the second position, the second support part can be attached to or detached from the holding part through the opening by moving the holding part and the second support part closer to or farther apart in the intersecting direction. On the other hand, with the chair body in the first position with the second support part housed in the holding part, the second support part can be prevented from being detached from the holding part through the opening. This improves assembly even in a configuration in which the first member and the second member are combined integrally.

[0010] In the chair of the above aspect, it is preferable that a regulating portion is removably provided on one of the second member and the support structure, which engages with the other of the second member and the support structure when the chair body is in the first position and regulates the rotation of the chair body to the second position around the first axis. According to this aspect, after the second member is assembled to the support structure, the second member can be prevented from returning to the second position, thereby ensuring both ease of assembly and reliability after assembly.

[0011] In the chair of the above aspect, it is preferable that the first member has another opening that opens in the front-to-rear direction and into which the first support part can be inserted, a slit extending in the front-to-rear direction is formed, and the first support part is configured to be movable in the front-to-rear direction within the slit. According to this aspect, the second support portion can be inserted into the slit through another opening, thereby improving the ease of assembling the first member to the support structure. [Effects of the Invention]

[0012] According to the above aspects, the discomfort felt by the seated occupant can be reduced. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a side view of a chair according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the chair body and the support base in the embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5] FIG. 3 is a cross-sectional view taken along line VV in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 2. [Figure 9] 9 is a cross-sectional view corresponding to FIG. 8, showing the chair body in the embodiment in an assembled position. [Figure 10] 4 is a cross-sectional view corresponding to FIG. 3, showing a state in which the retractable piece is in a retracted position. [Figure 11] FIG. 2 is a side view showing the reclining state of the backrest of the chair according to the embodiment. [Figure 12] 1 is a side view of the chair in the embodiment, showing the chair body in an assembled position. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of the present disclosure will be described with reference to the drawings. In the embodiments and modifications described below, the same reference numerals will be used to designate corresponding configurations, and the description thereof may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly indicate such arrangements, but also indicate a state in which there is a relative displacement with an angle or distance to the extent that tolerances or the same function are obtained. In this embodiment, "facing" is not limited to cases in which the orthogonal directions (normal directions) of two surfaces are aligned with each other, but also includes cases in which the orthogonal directions intersect with each other.

[0015] FIG. 1 is a side view of the chair 1. As shown in Figure 1, chair 1 comprises a support structure 2 and a chair body 3. In the following description, the directions of front, back, up, down, left, right, etc. are the same as the directions of a person (seater) sitting in the correct posture on chair 1. In this case, the arrow UP in the figure indicates upward, the arrow FR indicates forward, and the arrow LH indicates left. In the following description, the side of chair 1 that is away from the center in the front, back, and left, right directions (width direction) may be referred to as the outside, and the side that faces the center may be referred to as the inside.

[0016] <Support structure 2> The support structure 2 includes legs 11 and a base 12 . The leg portion 11 includes a multi-pronged leg 14 and a leg column 15 . Each leg of the multi-legged base 14 is fitted with a caster 16 that can run on the floor surface F.

[0017] The leg pillar 15 stands upright from the center of the multi-legged leg 14. The leg pillar 15 houses a gas spring 17, which is a mechanism for raising and lowering the chair 1. The gas spring 17 is configured such that an inner cylinder 17a is supported by an outer cylinder (not shown) provided inside the leg pillar 15 so as to be able to rise and fall and rotate relative to the outer cylinder.

[0018] 2 is a perspective view of the chair body 3 and the support base 12. Note that in FIG. 2, the upholstery material 111 of the chair body 3 is omitted. 1 and 2, the support base 12 is fixed to the upper end of the pillar 15 (inner cylinder 17a). As shown in Fig. 2, the support base 12 includes a casing 21, a lifting operation mechanism 22, a tilting mechanism 23, and a tilt adjustment mechanism 24.

[0019] The casing 21 is formed in a box shape that opens upward. The casing 21 is integrally molded from aluminum or the like. Specifically, the casing 21 includes a case main body 31, a pair of forward extending portions 32, and a rear case 33.

[0020] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 3, an insertion opening 31a penetrating the bottom wall is formed in the bottom wall of the case body 31. The inner cylinder 17a is assembled to the casing 21 through the insertion opening 31a.

[0021] 2, the pair of forward extending portions 32 extend forward from both left and right ends of the case body 31. In a side view, the pair of forward extending portions 32 extend at an upward incline as they move forward. In a plan view, the pair of forward extending portions 32 extend outward in the left and right direction as they move forward. The rear case 33 extends rearward from the center in the left-right direction of the case main body 31. The left-right width of the rear case 33 is narrower than that of the case main body 31. Note that ribs, lightening holes, etc. are provided inside the casing 21 as appropriate.

[0022] The lifting operation mechanism 22 includes a bearing portion 41 and an operation rod 42 . The bearing portion 41 is provided in the case body 31 on the right side of the insertion opening 31a. The operating rod 42 is supported by the bearing portion 41 so as to be rotatable about an axis along the left-right direction. The inner left-right end of the operating rod 42 is connected to the inner cylinder 17a inside the case body 31. The outer left-right end of the operating rod 42 penetrates the side wall of the case body 31 and protrudes to the right with respect to the case body 31. A handle (not shown) is attached to the outer left-right end of the operating rod 42 outside the casing 21. The lifting operation mechanism 22 operates the gas spring 17 by rotating the operating rod 42 via the handle.

[0023] The tilting mechanism 23 includes a slider (first support portion: see FIG. 4) 51 and a backrest support shaft (second support portion) 52.

[0024] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. Fig. 5 is a cross-sectional view taken along line VV in Fig. 2. As shown in Figures 4 and 5, the slider 51 is provided at the front end of each forward extending portion 32. The slider 51 includes a linking portion 55 and an entry restriction piece 56. The linking portion 55 is formed in an I-shaped block shape when viewed from the front. The linking portion 55 includes a lower wall portion 57, a pillar portion 58, and an upper wall portion 59. The lower wall portion 57 is fixed onto the front end portion of the forward extending portion 32 with screws 60 or the like. The pillar portion 58 extends upward from the center of the lower wall portion 57 in the left-right direction. The upper wall portion 59 protrudes from the pillar portion 58 on both sides in the left-right direction. As shown in FIG. 5, the entry restriction piece 56 extends forward from the linking portion 55 in a cantilevered manner.

[0025] 2, the backrest support shaft 52 is a shaft member that passes through the rear case 33 in the left-right direction. Both left-right ends of the backrest support shaft 52 protrude from the side walls of the rear case 33 to the outside of the rear case 33.

[0026] The tilt adjustment mechanism 24 includes a bearing portion 61 , an operating rod 62 , and a link mechanism 63 . The bearing portion 61 is provided on the left side of the insertion opening 31a in the case body 31. The operating rod 62 is supported by the bearing portion 61 so as to be rotatable about an axis along the left-right direction. The outer left-right end of the operating rod 62 penetrates the side wall of the case body 31 and protrudes to the left side relative to the case body 31. A handle (not shown) is attached to the outer left-right end of the operating rod 62 outside the casing 21.

[0027] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. As shown in FIGS. 3 and 6, the link mechanism 63 includes a first arm 71, a second arm 72, a guide portion 73, and a reciprocating piece 74. As shown in Fig. 6, the first arm 71 is fixed to the inner end of the operating rod 62 in the left-right direction. The first arm 71 extends from the operating rod 62 in the radial direction (downward) of the operating rod 62. A linking pin 71a protrudes inward in the left-right direction from the tip of the first arm 71. The linking pin 71a moves in the front-rear direction around the operating rod 62 as the operating rod 62 rotates.

[0028] The second arm 72 is configured to be movable in the front-rear direction in accordance with the movement of the linking pin 71a in the front-rear direction in response to the rotation of the operating rod 62. The second arm 72 includes a first connecting piece 75, a connecting piece 76, and a second connecting piece 77 (see FIG. 3). The first connecting piece 75 is formed in a plate shape with its thickness in the left-right direction. An insertion hole 75a is formed in the lower end of the first connecting piece 75. The insertion hole 75a is formed as an elongated hole. The linking pin 71a is inserted into the insertion hole 75a. The connecting piece 76 extends rearward from the upper end of the connecting piece 75. As shown in Fig. 2, the connecting piece 76 extends rearward while being bent in a crank shape in the left-right direction in a plan view. The rear end of the connecting piece 76 is located rearward of the backrest support shaft 52 within the rear case 33. As shown in FIG. 3, the second linking piece 77 protrudes downward from the rear end of the connecting piece 76.

[0029] The guide portion 73 is fixed inside the rear case 33 in a state where it is inserted into a through-hole 33b formed in the rear wall portion 33a of the rear case 33. The guide portion 73 includes an upper plate 78 and a lower plate 79 that face each other in the vertical direction. The space surrounded by the upper plate 78 and the lower plate 79 constitutes the sliding space S1. An upper slit 78a extending in the front-rear direction is formed in the upper plate 78. A lower slit 79a extending in the front-rear direction is formed in the lower plate 79 at a position opposite the upper slit 78a. A second connecting piece 77 spans between the upper slit 78a and the lower slit 79a. The second connecting piece 77 is inserted into the upper slit 78a from above the upper plate 78 and traverses the sliding space S1 in the vertical direction.

[0030] The advancing / retreating piece 74 is accommodated within the slide space S1 so as to be movable in the front-rear direction. The advancing / retreating piece 74 is formed like a plate extending in the front-rear direction, with the thickness direction being the up-down direction. The advancing / retreating piece 74 is connected to the second connecting piece 77 within the slide space S1. The advancing / retreating piece 74 moves in the front-rear direction as the second arm 72 moves in the front-rear direction. The advancing / retreating piece 74 moves in the front-rear direction between a protruding position (see FIG. 3) in which it protrudes rearward from the casing 21 through the through hole 33b, and a retracted position (see FIG. 10) in which it is retracted within the casing 21. The advancing / retreating piece 74 may be connected to the second connecting piece 77 in a state where it is biased toward the protruding position by a biasing member such as a spring, or may be directly connected to the second connecting piece 77.

[0031] <Chair body 3> As shown in FIG. 1, the chair body 3 includes a seat 100 and a backrest 101. The seat 100 extends in the front-to-rear direction in a side view. In the illustrated example, the seat 100 slopes downward from the rear to the front. The upper surface of the seat 100 forms a seat surface 100a that supports the area from the buttocks to the thighs of the seated person from below. The seat 100 is supported on the support base 12 so that it can slide in the front-to-rear direction. The backrest 101 extends upward from the rear end of the seat 100. In this embodiment, the backrest 101 has a gentle S-shape when viewed from the side. The front of the backrest 101 forms a back support surface 101a that supports the waist and back of the seated person from behind. The chair body 3 may also be provided with armrests.

[0032] The backrest 101 is provided so as to be rotatable about an axis O1 along the left-right direction relative to the seat 100. The backrest 101 is connected to the support base 12 so as to be rotatable about an axis O2 of the backrest support shaft 52. The seat 100 is provided so as to be slidable in the front-rear direction relative to the support base 12 as the backrest 101 rotates about the axis O2 relative to the support base 12 and as the backrest 101 rotates about the axis O1 relative to the seat 100.

[0033] The specific configuration of the chair body 3 will be described below. The chair body 3 includes a shell 110 and an upholstery material 111. The shell 110 is a frame-shaped member that forms the outer shell of the chair body 3. The shell 110 includes a seat frame 120 that forms the outer shell of the seat 100, a back frame 123 that forms the outer shell of the backrest 101, and a connecting member 121 that connects the seat frame 120 and the back frame 123. The seat frame 120, the connecting member 121, and the back frame 123 are each molded from a resin material or the like.

[0034] 2, the seat frame 120 is formed in a U-shape that opens rearward in a plan view. Specifically, the seat frame 120 includes a front rod portion 130, a side rod portion 131, a seat engagement portion 132 (see FIG. 4), and a spring accommodating portion 133 (see FIG. 4).

[0035] The front rod 130 extends in the left-right direction at the front end of the seat 100. The side rods 131 extend rearward from both left and right ends of the front rod 130.

[0036] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 7, a recess 131a that opens onto the rear end surface is formed on the rear end surface of each side rod portion 131. The rear end surface of each side rod portion 131 is formed as an inclined surface that extends forward as it extends downward.

[0037] 4 and 5, the seat engaging portion 132 is supported by the slider 51 so as to be movable in the front-rear direction relative to the support base 12. The seat engaging portion 132 is formed integrally with the front rod portion 130 or the side rod portion 131 at both left-right ends of the front rod portion 130. In the following explanation, the configuration of the seat engaging portion 132 will be explained using one of the seat engaging portions 132 as an example.

[0038] The seat engagement portion 132 is formed in a cylindrical shape extending in the front-rear direction. In this embodiment, the seat engagement portion 132 extends while inclining or curving slightly downward as it extends rearward. The seat engagement portion 132 has a rear end opening 132a (see FIG. 5) that opens rearward. A slit 132c is formed in the bottom wall portion 132b of the seat engagement portion 132. The slit 132c extends in the front-rear direction. The slit 132c has a slit opening (another opening) 132e that opens on the rear end surface of the bottom wall portion 132b. A recess 135 is formed in the front rod portion 130 at a position facing the seat engagement portion 132 in the front-rear direction. The recess 135 extends in the front-rear direction on an extension of the slit 132c. The recess 135 opens rearward and downward.

[0039] The slider 51 is accommodated in the seat engagement portion 132 through the rear end opening 132a and the slit opening 132e. Specifically, the slider 51 has a pillar portion 58 that passes through the slit 132c in the up-down direction, and an upper wall portion 59 that is disposed in the seat engagement portion 132. Therefore, the pillar portion 58 is configured to be movable in the front-rear direction within the slit 132c, with its movement in the left-right direction restricted by the inner surface of the slit 132c. The upper wall portion 59 is configured to be movable in the front-rear direction within the seat engagement portion 132, with its movement in the up-down direction restricted by the bottom wall portion 132b and top wall portion 132d of the seat engagement portion 132.

[0040] The entry restriction piece 56 overlaps with the slit 132c in plan view within the seat engagement portion 132. The entry restriction piece 56 enters or retreats from the relief portion 135 as the slider 51 moves forward or backward. The entry restriction piece 56 restricts the entry of fingers, objects, etc. into the seat engagement portion 132 through the slit 132c.

[0041] The spring accommodating portion 133 is formed integrally with the seat engaging portion 132 above the seat engaging portion 132. The spring accommodating portion 133 is formed in a cylindrical shape that opens toward the rear. The spring accommodating portion 133 is formed with a slide allowing portion 133a that opens toward the inside in the left-right direction. The slide allowing portion 133a is a slit that extends in the front-rear direction and opens on the rear end edge of the spring accommodating portion 133.

[0042] As shown in FIG. 7, the connecting member 121 includes a seat connecting portion 140, a back connecting portion 141, and a pivot portion 142. The seat connector 140 is a rod-shaped member that extends in the front-to-rear direction. The seat connector 140 is inserted from the rear into the recess 131a of the side rod 131. The seat connector 140 is fixed to the side rod 131 by fastening screws or the like to the side rod 131 from the inside in the left-right direction.

[0043] The back connector 141 is formed in a rod shape extending rearward from the rear end of the seat connector 140. The front end of the back connector 141 overlaps with the rear end of the seat connector 140 in the left-right direction. The pivot part 142 is formed in a rod shape extending in the left-right direction. The pivot part 142 passes through the overlapping part of the rear end of the seat connecting part 140 and the front end of the back connecting part 141 in the left-right direction. Therefore, the seat connecting part 140 and the back connecting part 141 are configured to be rotatable around the axis O1 of the pivot part 142.

[0044] The back frame 123 includes a lower frame 150, a main frame 151, and a support frame 152 (see FIG. 2). The lower frame 150 is connected to the rear ends of the side rods 131 via connecting members 121. The lower frame 150 slopes upward as it extends rearward. A recess 150a that opens forward is formed in the front end surface of the lower frame 150. A back connecting portion 141 is inserted into the recess 150a. The back connecting portion 141 is fixed to the lower frame 150 by fastening screws or the like from the inside of the lower frame 150 in the left-right direction.

[0045] In this way, in the shell 110 of this embodiment, the seat frame 120 and the back frame 123 are integrally combined via the connecting member 121. As a result, the back frame 123 is configured to be rotatable relative to the seat frame 120 around the axis O1.

[0046] 2, the main body frame 151 is formed in a rectangular frame shape when viewed from the front. Specifically, the main body frame 151 includes a pair of vertical rods 155, a lower rod 156, and an upper rod 157. The pair of vertical rods 155 extend upward from the rear end of each lower frame 150. In a side view, the vertical rods 155 extend forward as they extend upward, and then extend rearward as they extend further upward.

[0047] The lower rod portion 156 spans the lower ends of the pair of vertical rod portions 155 in the left-right direction. The upper rod portion 157 spans the upper ends of the pair of vertical rod portions 155 in the left-right direction.

[0048] The support frame 152 bridges between the lower frames 150. The support frame 152 includes a pair of connection frames 160 and a support base connecting portion 161. The connection frames 160 extend inward in the left-right direction from each lower frame 150. The connection frames 160 extend while curving downward as they extend inward in the left-right direction.

[0049] As shown in FIG. 1, the base connecting portion 161 connects between the pair of connection frames 160. The base connecting portion 161 is located below the lower frame 150 in a side view. As shown in FIG. 2, the base connecting portion 161 is located inside the pair of lower frames 150 in the left-right direction. The base connecting portion 161 is formed in a U-shape that opens forward. As shown in FIG. 3, the base connecting portion 161 includes a restricting wall portion 165 and a pair of front protrusions 167. The restricting wall portion 165 extends in the left-right direction. The front protrusions 167 extend obliquely downward and forward from both left and right end portions of the restriction wall 165 .

[0050] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. As shown in FIG. 8 , a holding portion 168 is formed on the inner surface of the front end of the front protrusion 167. The holding portion 168 is a recess that opens inward in the left-right direction in the front protrusion 167. The holding portion 168 holds the portion of the backrest support shaft 52 that protrudes from the rear case 33. This allows the back frame 123 to be rotatable about an axis O2 that extends in the left-right direction, with the backrest support shaft 52 as a fulcrum. The holding portion 168 has an insertion opening (opening) 168a that opens on the front end surface of the front protrusion 167. The backrest support shaft 52 can be inserted into the holding portion 168 through the insertion opening 168a. When the backrest support shaft 52 is accommodated in the holding portion 168, the insertion opening 168a opens in the radial direction (intersecting direction) of the axis O2.

[0051] A retaining portion 170 is formed on the inner surface of the holding portion 168 in a portion facing the circumferential direction about the axis O2. The retaining portion 170 is an arc-shaped groove extending in the circumferential direction about the axis O2. The retaining portion 170 opens on the inner surface of the holding portion 168 and also opens inward in the left-right direction at the front protruding portion 167.

[0052] A protrusion 173 is formed on each of both side walls of the rear case 33 at a portion that faces the front protrusion 167 in the left-right direction. The protrusion 173 is housed in the retaining portion 170. The protrusion 173 moves forward and backward from the retaining portion 170 according to the angle θ of the back frame 123 relative to the seat frame 120 (see FIG. 1).

[0053] 1, the angle θ of the back frame 123 relative to the seat frame 120 is the angle between a first imaginary line L1 connecting the axis O1 and the front end of the seat frame 120 in a side view, and a second imaginary line L2 connecting the axis O1 and the upper end of the back frame 123. In this embodiment, when the angle θ of the chair body 3 is at the first angle, the protrusion 173 is housed in the retaining portion 170 (use position (first position)) as shown in FIG. 8. In the use position, the protrusion 173 engages (contacts) with the inner surface of the retaining portion 170 in the radial direction (front-rear direction) of the axis O2, thereby restricting rearward movement of the back frame 123 relative to the backrest support shaft 52.

[0054] FIG. 9 is a cross-sectional view corresponding to FIG. 8, showing the chair body 3 in the assembled position (second position). As shown in FIG. 9, when the angle θ of the chair body 3 is at a second angle smaller than the first angle, the protrusion 173 is disengaged from the retaining portion 170 (attached position). At the assembled position, the entire protrusion 173 is positioned within the retaining portion 168, thereby disengaging (contacting) with the retaining portion 170. That is, at the assembled position, the back frame 123 is allowed to move radially (rearward) about the axis O2 relative to the backrest support shaft 52. As a result, the backrest support shaft 52 and the protrusion 173 are configured to be disengageable from the retaining portion 168. Note that it is only necessary that the amount of protrusion of the protrusion 173 into the retaining portion 168 at the assembled position is greater than the amount of protrusion into the retaining portion 168 at the use position.

[0055] As shown in Fig. 6, vertical grooves 180 are formed on the front surface of the restriction wall portion 165. The vertical grooves 180 extend in the up-down direction at both left-right end portions of the restriction wall portion 165. A return stopper (restriction portion) 181 is engaged in each vertical groove 180. In the following explanation, of the return stoppers 181, the return stopper 181 engaged in one of the vertical grooves 180 will be explained.

[0056] The return stopper 181 is detachably attached to the rear wall portion 33a and includes a shaft portion 181a, a flange portion 181b, and a knob portion 181c. The shaft 181a is formed in a rod shape extending in the front-rear direction. In the rear wall 33a of the rear case 33 described above, an insertion hole 33c penetrating the rear wall 33a is formed at a position facing the vertical groove 180 in the front-rear direction. The shaft 181a penetrates the rear wall 33a through the insertion hole 33c. The tip (rear end) of the shaft 181a protrudes rearward from the rear case 33. The tip of the shaft 181a enters the vertical groove 180. The return stopper 181 restricts rotation of the back frame 123 to the assembly position by the shaft 181a engaging (contacting) from above with the lower surface (the surface of the inner surface facing upward) of the vertical groove 180.

[0057] The flange portion 181b is formed at the base end (front end) of the shaft portion 181a with a larger diameter than the shaft portion 181a. The flange portion 181b is close to or abuts against the rear wall portion 33a from the front. The flange portion 181b has a tapered surface that extends obliquely upward and forward. The knob 181c protrudes upward from the flange 181b.

[0058] A positioning bolt 185 is provided in a portion of the rear case 33 that is located forward of the return stopper 181. The positioning bolt 185 is provided in a state where it protrudes from the bottom wall portion 33d of the rear case 33 into the rear case 33. The positioning bolt 185 is disposed in front of the flange portion 181b, and restricts forward movement of the return stopper 181 relative to the rear case 33. In other words, the positioning bolt 185 prevents the return stopper 181 from coming off the vertical groove 180.

[0059] As shown in FIG. 3 , a tilting restriction portion 190 is formed in the restriction wall portion 165 at a portion located between the vertical grooves 180. The tilting restriction portion 190 is a recess that opens on the front and bottom surfaces of the restriction wall portion 165. When the retractable piece 74 is in the protruding position, the rear end of the retractable piece 74 enters the tilting restriction portion 190. When the retractable piece 74 is in the protruding position, the top surface of the tilting restriction portion 190 comes into contact with the retractable piece 74 as the back frame 123 rotates rearward. This limits the range of rotation of the back frame 123 relative to the seat frame 120. On the other hand, as shown in FIG. 10 , when the retractable piece 74 is in the retracted position, the retractable piece 74 retracts from the tilting restriction portion 190. That is, when the retractable piece 74 is in the retracted position, the retractable piece 74 retracts from the rotation path of the back frame 123, thereby allowing the back frame 123 to rotate. When the advancing / retreating piece 74 is in the retracted position, the rotation range of the back frame 123 is limited by contacting a restricting portion (not shown) provided on the casing 21. Note that when the tilt restricting portion 190 is in the protruding position, the rotation range of the back frame 123 needs to be smaller than when the tilt restricting portion 190 is in the retracted position. In other words, when the tilt restricting portion 190 is in the protruding position, the rotation of the back frame 123 may be prevented, or the back frame 123 may rotate slightly.

[0060] The upholstery material 111 is fastened to the outer peripheral edge of the shell 110, thereby closing the opening of the shell 110 from the front and above. Specifically, the upholstery material 111 is fastened integrally along the outer peripheral edges of the seat frame 120 and the back frame 123. The portion of the upholstery material 111 that covers the seat frame 120 forms the seat surface 100a. The portion of the upholstery material 111 that covers the back frame 123 forms the back support surface 100b. The upholstery material 111 is formed by combining stretchable synthetic resin fibers in a mesh shape. However, the upholstery material 111 is not limited to a mesh shape, and can be, for example, a cloth or film shape, as long as it is configured to deform in response to the rotation of the backrest 101 relative to the seat 100.

[0061] 2, 4, and 5, a biasing mechanism 200 is interposed between the seat frame 120 and the support base 12. The biasing mechanism 200 biases the seat frame 120 forward. The biasing mechanism 200 includes a first biasing member 201, a holding member 202, and a second biasing member 203.

[0062] The first biasing member 201 is formed of an elastically deformable wire rod that is stretched between the casing 21 and the spring accommodating portion 133. Specifically, the first biasing member 201 has a central portion supported by the front end portion of the case main body 31, and both left and right end portions extend upward and outward in the left and right direction as they move forward along the inside of the forward extending portion 32. Both left and right end portions of the first biasing member 201 enter the spring accommodating portion 133 through the slide allowing portion 133a.

[0063] The holding member 202 is housed in the spring accommodating portion 133. An outer end portion of the first biasing member 201 in the left-right direction is connected to the holding member. The holding member 202 holds the first biasing member 201 rotatably around an axis along the left-right direction. A screw 205 that protrudes into the spring accommodating portion 133 is provided at the rear of the spring accommodating portion 133. The holding member 202 is positioned in the front-to-rear direction within the spring accommodating portion 133 by being sandwiched between the screw 205 and the second biasing member 203 in the front-to-rear direction.

[0064] The second biasing member 203 is, for example, a coil spring. The second biasing member 203 is housed in a portion of the spring accommodating portion 133 that is located in front of the retaining member 202. In other words, the first biasing member 201 is located rearward by the length of the second biasing member 203 in the front-to-rear direction. The second biasing member 203 is interposed between the front wall of the spring accommodating portion 133 and the retaining member 202, and biases the seat frame 120 forward.

[0065] (How to use Chair 1) Next, as a method of using the chair 1 described above, the operation when reclining the chair body 3 will be described. In the following explanation, the state in which the retractable piece 74 is in the retracted position will be described as the initial state. Figure 11 is a side view of the chair 1 showing the reclined state of the backrest 101. The chair 1 of this embodiment has a link mechanism in which the support base 12 (casing 21) is a fixed link, the back frame 123 is a rotating link, and the seat frame 120 is a sliding link. Specifically, when a seated person sits on the chair main body 3 and leans on the backrest 101, a rearward load acts on the chair main body 3 via the backrest 101. As a result, as shown in FIG. 11 , the backrest 101 rotates rearward relative to the support base 12 about axis O2. As a result, the backrest 101 rotates rearward relative to the seat 100 about axis O1. As a result, the seat 100 is pulled rearward as the backrest 101 rotates. At this time, the seat 100 is configured to be movable in the front-rear direction while its movement in the up-down direction is restricted by the slider 51, and therefore slides rearward relative to the support base 12 as the backrest 101 rotates. Furthermore, because the seat engaging portion 132 extends downward as it moves rearward, the seat 100 moves downward as it moves rearward. As a result, the entire chair body 3 moves rearward, and the backrest 101 reclines rearward. Furthermore, when the backrest 101 reclines, the biasing members 201, 203 elastically deform as the seat 100 moves rearward. This increases the biasing force of the biasing mechanism 200.

[0066] When the seated occupant stands up and the load acting on the backrest 101 is released, the seat 100 attempts to move forward due to the biasing force of the biasing mechanism 200. Accordingly, the backrest 101 rotates forward about axis O1 relative to the seat 100 and also rotates forward about axis O2 relative to the support base 12. As a result, the chair body 3 returns to its initial state. At this time, the biasing force of the coil spring serving as the second biasing member 203 is added to the biasing force of the first biasing member 201 made of wire, eliminating the need for excessively large elastic deformation of the first biasing member 201 made of wire. Furthermore, while the amount of movement of the seat 100 in the front-to-rear direction is set within a predetermined range, the first biasing member 201 is positioned rearward by the length of the second biasing member 203 in the front-to-rear direction, so the amount of front-to-rear displacement of the first biasing member 201 can be limited by the amount of elastic deformation of the second biasing member 203 in the front-to-rear direction. This makes it possible to prevent deterioration of the first biasing member 201 over time.

[0067] Next, the operation of the chair 1 when the retractable piece 74 is in the protruding position will be described. To move the retractable piece 74 to the protruding position, the operating rod 62 of the tilt adjustment mechanism 24 is rotated. The rotational motion of the operating rod 62 is then transmitted to the second arm 72 via the first arm 71, and converted into linear motion of the second arm 72 and the retractable piece 74. This causes the retractable piece 74 to slide rearward within the slide space S1. As a result, the retractable piece 74 protrudes rearward from the casing 21 and enters the tilt restriction portion 190. In this state, if an attempt is made to recline the backrest 101, the top surface of the tilt restriction portion 190 abuts against the retractable piece 74 from above, restricting the rotation of the backrest 101.

[0068] (How to assemble chair 1) Next, a method of assembling the chair 1 will be described, which involves assembling the chair body 3 to the support base 12. Fig. 12 is a side view of the chair 1 showing the chair body 3 in the assembled position. First, as shown in Fig. 12, with the shell 110 in the assembly position, the seat frame 120 and the support base 12 are connected. Specifically, as shown in Fig. 5, the slider 51 is inserted into the seat engagement portion 132 through the rear end opening 132a and the slit opening 132e of the seat engagement portion 132. At this time, the pillar portion 58 of the slider 51 is inserted into the slit 132c, and the upper wall portion 59 is inserted into the seat engagement portion 132.

[0069] The second biasing member 203 is inserted into the spring accommodating portion 133 through the rear end opening of the spring accommodating portion 133. Next, the holding member 202 is inserted through the rear end opening of the spring accommodating portion 133. At this time, the outer end of the first biasing member 201 in the left-right direction enters the slide allowing portion 133a. After that, the screw 205 is attached to the spring accommodating portion 133, and the tip of the screw 205 protrudes into the spring accommodating portion 133. As a result, the biasing mechanism 200 is assembled into the spring accommodating portion 133 with an initial biasing force stored in both the first biasing member 201 and the second biasing member 203. In this manner, the seat frame 120 is assembled to the support base 12.

[0070] Next, as shown in Fig. 9, the back frame 123 and the support base 12 are connected. Specifically, the backrest support shaft 52 is inserted into the holding portion 168 through the insertion opening 168a of the holding portion 168. Then, the back frame 123 is rotated to the use position. Then, the protrusion 173 enters the retaining portion 170, thereby restricting the rearward movement of the back frame 123 relative to the backrest support shaft 52.

[0071] Next, as shown in FIG. 6, return stopper 181 is assembled to casing 21. Specifically, shaft 181a of return stopper 181 is inserted into insertion hole 33c of rear wall 33a, causing the tip of shaft 181a to protrude from rear wall 33a. Then, the tip of shaft 181a enters vertical groove 180 of spine frame 123. This restricts rotation of spine frame 123 to the assembled position. Thereafter, positioning bolt 185 is assembled to casing 21, restricting forward movement of return stopper 181.

[0072] Then, the chair body 3 is assembled to the support base 12 by assembling the upholstery material 111 to the shell 110. Note that the above-mentioned assembly method may be performed after the upholstery material 111 is assembled to the shell 110.

[0073] (effect) In this way, in the chair 1 of this embodiment, the seat frame 120 and the back frame 123 are assembled so as to be rotatable around the first axis O1, and the support base 12 is configured to include a slider 51 that supports the seat frame 120 so as to be movable in the front-to-rear direction, and a backrest support axis 52 that supports the back frame 123 so as to be rotatable around the second axis O2. With this configuration, as the backrest 101 rotates about axis O2 relative to the support base 12, the backrest 101 (back frame 123) rotates about axis O1 relative to the seat 100 (seat frame 120), and the seat 100 slides in the front-to-rear direction relative to the support base 12. This makes it possible to suppress up-and-down movement of the seat 100 that accompanies the rotation of the backrest 101 backward, compared to a conventional configuration in which the front end of the seat lifts as the backrest rotates backward. In other words, as the backrest 101 rotates, the seat 100 can move smoothly in the front-to-rear direction, reducing the discomfort felt by the seated person when reclining.

[0074] The chair 1 of this embodiment is configured to include a connecting member 121 that connects the seat frame 120 and the back frame 123 to be rotatable about an axis O1. According to this configuration, by using the connecting member 121 separate from the seat frame 120 and the back frame 123, it is easy to adjust the amount of rotation of the back frame 123 relative to the seat frame 120 while ensuring the strength of the chair body 3.

[0075] The chair 1 of this embodiment is configured to have a retaining portion 170 that engages with the protrusion 173 in the opening direction of the insertion opening 168a when the chair body 3 (shell 110) is in the use position, thereby restricting movement of the back frame 123 relative to the support base 12 in the radial direction of the axis O2, and disengages from the protrusion 173 when the chair body 3 is in the assembly position, thereby allowing movement of the back frame 123 relative to the support base 12 in the radial direction of the axis O2. According to this configuration, with the chair body 3 in the assembled position, the holding portion 168 and the backrest support shaft 52 can be moved toward or away from each other in the radial direction of the axis O2, thereby allowing the backrest support shaft 52 to be attached to or detached from the holding portion 168 through the insertion opening 168a. On the other hand, by placing the chair body 3 in the in-use position with the backrest support shaft 52 housed within the holding portion 168, the backrest support shaft 52 can be prevented from coming off the holding portion 168 through the insertion opening 168a. This improves ease of assembly even in a configuration in which the seat 100 and the backrest 101 are combined as a single unit.

[0076] In the chair 1 of this embodiment, when the chair body 3 is in the use position, a return stopper 181 is removably provided on the support base 12, which engages with the back frame 123 and restricts rotation around the axis O1 to the assembly position. According to this configuration, it is possible to prevent the back frame 123 from returning to the assembled position after the back frame 123 is assembled to the support base 12. This ensures both ease of assembly and reliability after assembly.

[0077] In the chair 1 of this embodiment, the seat engaging portion 132 is open toward the rear and has a slit 132c extending in the front-rear direction, and the slider 51 is supported within the slit 132c so as to be movable in the front-rear direction. According to this configuration, the slider 51 can be inserted into the slit 132c through the rear end opening 132a of the seat engagement portion 132. This improves the ease of assembling the seat frame 120 to the support base 12.

[0078] (Other variations) Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of the present disclosure. The present disclosure is not limited by the above description, but is limited only by the scope of the appended claims. In the above-described embodiment, the seat frame 120 and the back frame 123 are rotatably connected via the connecting member 121, but the present invention is not limited to this configuration. The connecting member may have only a pivot portion that rotatably connects the seat frame 120 and the back frame 123. The connecting member may also be configured to be foldable. Furthermore, the chair body 3 may not have a connecting member. In this case, the seat frame 120 and the back frame 123 may be integrally formed so as to be foldable. In the above-described embodiment, the biasing mechanism 200 interposed between the seat frame 120 and the casing 21 is configured to include the first biasing member 201 made of a wire rod and the second biasing member 203 made of a coil spring, but is not limited to this configuration. The biasing mechanism 200 may be configured to include either the first biasing member 201 or the second biasing member 203.

[0079] In the above-described embodiment, the configuration in which the retaining portion 170 opens on the inner surface of the holding portion 168 has been described, but the present invention is not limited to this configuration. The retaining portion 170 may be provided at a position separate from the holding portion 168. In the above-described embodiment, a block-shaped slider 51 is used as the first support part, and a configuration in which a slit 132c is formed in the seat frame 120 is described, but the present invention is not limited to this configuration. The first support part only needs to support the seat frame 120 so that it can move in the front-to-rear direction. In this case, the first support part may be a slit, and a slider or the like that can move within the slit may be provided on the seat frame 120. The first support part and the seat frame 120 may be a combination of a rail and a roller, for example.

[0080] In the above-described embodiment, the backrest support shaft 52 is used as the second support portion, and the holding portion 168 is formed on the back frame 123. However, the present invention is not limited to this configuration. A shaft may be provided on the back frame 123, and a holding portion rotatably supported on the shaft may be provided on the second support portion. In the above-described embodiment, the return stopper 181 is provided on the base 12, but the present invention is not limited to this configuration. The return stopper 181 may be detachably provided on the back frame 123 and engaged with the base 12. In the above-described embodiment, the seat frame 120 of the chair main body 3 (shell 110) forms the outer shell of the seat 100, and the back frame 123 forms the outer shell of the backrest 101. However, the outer shell of the chair main body 3 may be formed by a first member that forms part of the outer shell of the seat 100 and a second member that forms part of the outer shell of the backrest 101. For example, the seat frame 120 may form the front half of the seat 100, and the back frame 123 may form the rear half of the seat 100 and the backrest 101. In this case, it is preferable that the seat frame 120 includes the front end of the chair main body 3 and forms an area that is at least half of the total length of the seat 100, and the back frame 123 includes the upper end of the chair main body 3.

[0081] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0082] 1. Chair 2...Support structure 3...Chair body 51...Slider (first support portion) 52...Backrest support shaft (second support part) 100…za 121...Connecting member 132c...slit 132e...Slit opening (other opening) 168...Holding part 168a...insertion opening (opening) 170...Prevention part 181...Return stopper (regulating part)

Claims

1. a support structure; a chair body including a first member extending in the front-rear direction and constituting at least a part of a seat, and a second member provided at a rear end of the first member so as to be rotatable about a first axis along the left-right direction, and extending upward from the first member and constituting at least a part of a backrest; The support structure includes: a first support portion that supports the first member in front of the first axis so that the first member can move in a front-rear direction; A chair comprising: a second support portion below the first axis that supports the second member rotatably around a second axis along the left-right direction.

2. The chair according to claim 1, wherein the chair body includes a connecting member that connects the first member and the second member so as to be rotatable about the first axis.

3. the chair body is configured to be rotatable between a first position where an angle formed between the first member and the second member about the first axis is a first angle, and a second position where an angle formed between the first member and the second member about the first axis is a second angle smaller than the first angle, the second support portion is a shaft member extending along the second axis, The second member is a holding portion having an opening portion that opens toward a direction intersecting the second axis and into which the second support portion can be inserted, the holding portion holding the second support portion; 3. The chair of claim 1, further comprising a retaining portion that engages with the support structure in the transverse direction when the chair body is in the first position, restricting movement of the second member relative to the support structure in the transverse direction, and that disengages from the support structure when the chair body is in the second position, allowing movement of the second member relative to the support structure in the transverse direction.

4. The chair of claim 3, wherein a regulating portion is removably provided on one of the second member and the support structure, which engages with the other of the second member and the support structure when the chair body is in the first position, and regulates the rotation of the chair body to the second position around the first axis.

5. the first member has another opening that opens in the front-rear direction and into which the first support portion can be inserted, and a slit that extends in the front-rear direction is formed; The chair according to any one of claims 1 to 4, wherein the first support portion is configured to be movable in the front-rear direction within the slit.

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