Chair

Abstract

A chair (1) according to one embodiment of the present disclosure comprises: a support base (12); and a chair body (3) including a seat frame (120) that extends in the front-back direction and constitutes at least a portion of a seat (100), and a back frame (123) that is provided to a back end of the seat frame (120) so as to be rotatable around an axis line O1 along the left-right direction, and that extends upward from the seat frame (120) and constitutes at least a portion of a seat back (101). The support base (12) includes: a slider that supports the seat frame (120) in front of the axis line O1 so as to be movable in the front-back direction; and a seat back support shaft that supports the back frame (123) below the axis line O1 so as to be rotatable around an axis line O2 along the left-right direction.

Description

Technical Field

[0001] The present disclosure relates to a chair.

Background Art

[0002] For example, Patent Document 1 below discloses a reclining chair including a chair body in which a seat and a backrest are integrally combined, and a support structure that rotatably supports the chair body. In Patent Document 1 below, the front end portion of the seat is rotatably connected to the support structure. The lower end portion of the backrest is rotatably connected to the support structure. The seat and the backrest are rotatably connected to each other. In the type of chair described in Patent Document 1 below, as the backrest rotates backward with respect to the support structure, the backrest rotates with respect to the seat and the seat rotates with respect to the support structure. As a result, the chair reclines with the front end portion of the seat lifted upward.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional configuration, when the backrest is tilted (reclined) while the user is seated on the chair, the thigh of the seated person is pushed up by the front end portion of the seat. Therefore, the seated person may feel that the thigh is compressed, and the seated person may feel discomfort.

[0005] An object of the present disclosure is to provide a chair that can reduce discomfort given to a seated person.

Means for Solving the Problems

[0006] In order to solve the above problems, the present disclosure adopts the following aspects. A chair according to an aspect of the present disclosure includes a support structure, a first member that extends in the front-rear direction and constitutes at least a part of a seat, and a second member that is provided rotatably around a first axis along the left-right direction at the rear end of the first member and extends upward from the first member to constitute at least a part of a backrest. The support structure includes a first support portion that supports the first member movably in the front-rear direction in front of the first axis, and a second support portion that supports the second member rotatably around a second axis along the left-right direction below the first axis.

[0007] According to this aspect, as the second member rotates around the second axis with respect to the support structure, the second member rotates around the first axis with respect to the first member, and the first member slides in the front-rear direction with respect to the support structure. Thereby, compared with a configuration in which the front end portion of the seat is lifted as the backrest rotates rearward as in the prior art, it is possible to suppress the vertical movement of the first member as the second member rotates rearward. That is, as the second member rotates, the first member can be smoothly moved in the front-rear direction, so that the discomfort given to the seated person during reclining can be reduced.

[0008] In the chair of the above aspect, it is preferable that the chair body includes a connecting member that rotatably connects the first member and the second member around the first axis. According to this aspect, by using a connecting member separate from the first member and the second member, it is easy to adjust the rotation amount and the like of the second member with respect to the first member while ensuring the strength of the chair body.

[0009] In the chair according to the above aspect, the chair body is configured to be rotatable between a first position where the angle formed by the first member and the second member around the first axis is a first angle, and a second position where the angle formed by the first member and the second member around 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 has an opening that opens in a crossing direction intersecting the second axis and into which the second support portion can be inserted, a holding portion that holds the second support portion, and a retaining portion that engages with the support structure in the crossing direction when the chair body is in the first position to restrict movement of the second member in the crossing direction with respect to the support structure, and disengages from the support structure when the chair body is in the second position to allow movement of the second member in the crossing direction with respect to the support structure. It is preferable that the chair has such a retaining portion. According to this aspect, in a state where the chair body is in the second position, the second support portion can be attached to and detached from the holding portion through the opening by approaching or separating the holding portion and the second support portion in the crossing direction. On the other hand, in a state where the second support portion is accommodated in the holding portion, by setting the chair body to the first position, it is possible to suppress the second support portion from detaching from the holding portion through the opening. Thereby, even in a configuration in which the first member and the second member are integrally combined, the assemblability can be improved.

[0010] In the chair according to the above aspect, it is preferable that a restricting portion that engages with the other member of the second member and the support structure when the chair body is in the first position to restrict rotation of the chair body to the second position around the first axis is detachably provided on one of the second member and the support structure. According to this aspect, after the second member is assembled to the support structure, it is possible to restrict the second member from returning to the second position. Thereby, both assemblability and reliability after assembly can be ensured.

[0011] In the chair of the above aspect, the first member has another opening that opens in the front-rear direction and into which the first support portion can be inserted, a slit extending in the front-rear direction is formed, and the first support portion is configured to be movable in the front-rear direction within the slit. According to this aspect, the second support portion can be inserted into the slit through the other opening. Thereby, the assemblability of the first member to the support structure can be improved.

Effects of the Invention

[0012] According to each of the above aspects, the discomfort given to the seated person can be reduced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Best Mode for Carrying Out the Invention

[0014] Next, embodiments of the present disclosure will be described with reference to the drawings. In the embodiments and modifications described below, corresponding components may be denoted by the same reference numerals and the description thereof may be omitted. In the following description, expressions indicating relative or absolute arrangements such as "parallel", "orthogonal", "center", "coaxial", etc. not only strictly represent such arrangements, but also include states in which there are tolerances or relative displacements with angles and distances that provide the same function. In the present embodiment, the term "opposite" includes not only the case where the orthogonal directions (normal directions) of two surfaces coincide with each other, but also the case where the orthogonal directions intersect each other.

[0015] FIG. 1 is a side view of the chair 1. As shown in FIG. 1, the chair 1 includes a support structure 2 and a chair body 3. In the following description, the directions such as front, rear, up, down, left, and right are the same as those of a person (seated person) sitting in the regular posture on the chair 1. In this case, the arrow UP in the figure indicates upward, the arrow FR indicates forward, and LH indicates left. Further, in the following description, in the chair 1, the sides spaced apart from the center in the front-rear direction and the left-right direction (width direction) may be referred to as the outer sides, and the sides facing the center may be referred to as the inner sides.

[0016] <Support Structure 2> The support structure 2 includes legs 11 and a support base 12. The legs 11 include multi-branched legs 14 and leg posts 15. Casters 16 capable of traveling on the floor surface F are attached to each leg of the multi-branched legs 14.

[0017] The leg post 15 is erected upward from the central portion of the multi-branched legs 14. A gas spring 17, which is a lifting mechanism of the chair 1, is built in the leg post 15. The gas spring 17 has a configuration in which an inner cylinder 17a is supported so as to be able to move up and down and rotate relative to an outer cylinder (not shown) provided in the leg post 15, for example.

[0018] Figure 2 is a perspective view of the chair body 3 and the support base 12. In Figure 2, the tension member 111 of the chair body 3 is omitted. As shown in FIGS. 1 and 2, the support base 12 is fixed to the upper end of the leg column 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 tilting adjustment mechanism 24.

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

[0020] Figure 3 is a cross-sectional view taken along line III-III of FIG. 2. As shown in FIG. 3, an insertion port 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 port 31a.

[0021] As shown in FIG. 2, the pair of front extending portions 32 extend forward from both ends in the left-right direction of the case body 31. The pair of front extending portions 32 extend obliquely upward as they extend forward in a side view. The pair of front extending portions 32 extend outward in the left-right direction as they extend forward in a plan view. The rear case 33 extends rearward from the central portion in the left-right direction of the case body 31. In the rear case 33, the width in the left-right direction is narrower than that of the case body 31. Note that ribs, cutouts, etc. are appropriately provided in the casing 21.

[0022] The lifting operation mechanism 22 includes a bearing portion 41 and an operation rod 42. The bearing portion 41 is provided on the right side of the insertion port 31a in the case body 31. The operating rod 42 is supported by a bearing portion 41 so as to be rotatable about an axis along the left - right direction. The inner end portion of the operating rod 42 in the left - right direction is linked to the inner cylinder 17a within the case body 31. The outer end portion of the operating rod 42 in the left - right direction penetrates the side wall of the case body 31 and protrudes to the right side with respect to the case body 31. A handle (not shown) is attached to the outer end portion of the operating rod 42 in the left - right direction outside the casing 21. The lifting and lowering operation mechanism 22 operates the gas spring 17 by rotationally operating 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 of FIG. 2. FIG. 5 is a cross - sectional view taken along line V - V of FIG. 2. As shown in FIGS. 4 and 5, the slider 51 is provided at the front end portion of each front - extending portion 32. The slider 51 includes a linking portion 55 and an entry restricting piece 56. The linking portion 55 is formed in an I - shaped block shape in a front view. The linking portion 55 includes a lower wall portion 57, a column portion 58, and an upper wall portion 59. The lower wall portion 57 is fixed to the front end portion of the front - extending portion 32 by screws 60 or the like. The column portion 58 extends upward from the central portion of the lower wall portion 57 in the left - right direction. The upper wall portion 59 projects to both sides in the left - right direction with respect to the column portion 58. As shown in FIG. 5, the entry restricting piece 56 extends cantilever - like forward from the linking portion 55.

[0025] As shown in FIG. 2, the backrest support shaft 52 is a shaft member that penetrates the rear case 33 in the left - right direction. Both end portions of the backrest support shaft 52 in the left - right direction protrude from the side wall of the rear case 33 to the outside of the rear case 33.

[0026] The tilting 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 with respect to the insertion port 31a in the case main body 31. The operation rod 62 is supported by the bearing portion 61 so as to be rotatable about an axis along the left - right direction. The outer end portion of the operation rod 62 in the left - right direction penetrates the side wall of the case main body 31 and protrudes to the left side with respect to the case main body 31. A handle (not shown) is attached to the outer end portion of the operation rod 62 in the left - right direction outside the casing 21.

[0027] FIG. 6 is a cross - sectional view taken along line VI - VI of FIG. 2. 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 portion of the operation rod 62 in the left - right direction. The first arm 71 extends from the operation rod 62 in the radial direction (downward) of the operation rod 62. A linking pin 71a protrudes inward in the left - right direction at the tip of the first arm 71. The linking pin 71a moves back and forth around the operation rod 62 as the operation rod 62 rotates.

[0028] The second arm 72 is configured to be movable in the front - rear direction as the linking pin 71a moves in the front - rear direction due to the rotation of the operation 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 the left - right direction as the thickness direction. An insertion hole 75a is formed at the lower end of the first connecting piece 75. The insertion hole 75a is formed as a long 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 in a bent state in a crank shape in the left - right direction in plan view. The rear end portion of the connecting piece 76 is located behind the back - rest support shaft 52 in the rear case 33. As shown in FIG. 3, the second connecting piece 77 protrudes downward from the rear end of the connecting piece 76.

[0029] The guide portion 73 is fixed within the rear case 33 while being 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 a slide space S1. An upper slit 78a extending in the front-rear direction is formed in the upper plate 78. In the lower plate 79, a lower slit 79a extending in the front-rear direction is formed at a position facing the upper slit 78a. A second connecting piece 77 is bridged 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 slide 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 in a plate shape with the vertical direction as the thickness direction and extending in the front-rear 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) protruding rearward from the casing 21 through the through hole 33b and a retracted position (see FIG. 10) retracted within the casing 21. Note that the advancing / retreating piece 74 may be connected to the second connecting piece 77 in a state of being 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-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 constitutes a seat surface 100a that supports the range from the buttocks to the thighs of the seated person from below. The seat 100 is supported so as to be slidable in the front-rear direction with respect to the support base 12. The backrest 101 extends upward from the rear end of the seat 100. The backrest 101 of the present embodiment forms a gentle S shape in a side view. The front surface of the backrest 101 constitutes a backrest surface 101a that supports the waist and back of the seated person from behind. Note that the chair body 3 may be provided with armrests.

[0032] The backrest 101 is provided so as to be rotatable about an axis O1 along the left - right direction with respect 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 with respect to the support base 12 as the backrest 101 rotates about the axis O2 with respect to the support base 12 and as the backrest 101 rotates about the axis O1 with respect to the seat 100.

[0033] Hereinafter, the specific configuration of the chair body 3 will be described. The chair body 3 includes a shell 110 and a tension member 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 constitutes the outer shell of the seat 100, a back frame 123 that constitutes the outer shell of the backrest 101, and a connecting member 121 that connects the seat frame 120 and the back frame 123. Note that the seat frame 120, the connecting member 121, and the back frame 123 are each formed of a resin material or the like.

[0034] As shown in FIG. 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, side rod portions 131, a seat engagement portion 132 (see FIG. 4), and a spring housing portion 133 (see FIG. 4).

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

[0036] FIG. 7 is a cross - sectional view taken along line VII - VII of FIG. 2. As shown in FIG. 7, a recess 131a that opens on the rear end surface is formed on the rear end surface of each side rod portion 131. Note that the rear end surface of the side rod portion 131 is formed as an inclined surface that extends forward as it goes downward.

[0037] As shown in FIGS. 4 and 5, the seat engagement portion 132 is supported by a slider 51 so as to be movable in the front-rear direction with respect to the support base 12. The seat engagement portion 132 is integrally formed with the front rod portion 130 or the side rod portion 131 at both left and right ends in the left-right direction of the front rod portion 130. In the following description, the configuration of the seat engagement portion 132 will be described by taking one seat engagement portion 132 as an example.

[0038] The seat engagement portion 132 is formed in a cylindrical shape that extends in the front-rear direction. In the present embodiment, the seat engagement portion 132 extends while being slightly inclined or curved downward as it goes 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 (other opening) 132e that opens on the rear end surface of the bottom wall portion 132b. In the front rod portion 130, a relief portion 135 is formed at a position that faces the seat engagement portion 132 in the front-rear direction. The relief portion 135 extends in the front-rear direction on the extension line of the slit 132c. The relief portion 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 is disposed in the seat engagement portion 132 with the column portion 58 penetrating the slit 132c in the vertical direction and the upper wall portion 59. Therefore, the column portion 58 is configured to be movable in the front-rear direction within the slit 132c while being restricted from moving in the left-right direction 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 while being restricted from moving in the vertical direction by the bottom wall portion 132b and the top wall portion 132d of the seat engagement portion 132.

[0040] The entry regulating plate 56 overlaps with the slit 132c in a plan view within the seat engagement portion 132. The entry regulating plate 56 enters or retracts with respect to the relief portion 135 as the slider 51 moves in the front-rear direction. The entry regulating plate 56 regulates the entry of fingers, articles, etc. into the seat engagement portion 132 through the slit 132c.

[0041] The spring housing portion 133 is formed integrally with the seat engagement portion 132 above the seat engagement portion 132. The spring housing portion 133 is formed in a cylindrical shape that opens rearward. A slide allowance portion 133a that opens inward in the left-right direction is formed in the spring housing portion 133. The slide allowance portion 133a is a slit that extends in the front-rear direction and opens on the rear edge of the spring housing 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 connecting portion 140 is a rod-shaped member that extends in the front-rear direction. The seat connecting portion 140 is inserted into the concave portion 131a of the side rod portion 131 from the rear. The seat connecting portion 140 is fixed to the side rod portion 131 by fastening a screw or the like from the inner side in the left-right direction to the side rod portion 131.

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

[0044] The back frame 123 includes a lower frame 150, a main body frame 151, and a support frame 152 (see FIG. 2). The lower frame 150 is connected to the rear end of the side rod portion 131 via a connecting member 121. The lower frame 150 is inclined upward as it extends rearward. A recess 150a that opens forward is formed on the front end face 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 inner side in the left-right direction with respect to the lower frame 150.

[0045] As described above, in the shell 110 of the present embodiment, the seat frame 120 and the back frame 123 are integrally combined via the connecting member 121. Thereby, the back frame 123 is configured to be rotatable about the axis O1 with respect to the seat frame 120.

[0046] As shown in FIG. 2, the main body frame 151 is formed in a rectangular frame shape in a front view. Specifically, the main body frame 151 includes a pair of vertical rod portions 155, a lower rod portion 156, and an upper rod portion 157. The pair of vertical rod portions 155 extend upward from the rear ends of the respective lower frames 150. In a side view, the vertical rod portion 155 extends forward as it extends upward, and then extends rearward as it further extends upward.

[0047] The lower rod portion 156 bridges the lower ends of the pair of vertical rod portions 155 in the left-right direction. The upper rod portion 157 bridges 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 connection portion 161. The connection frame 160 extends from each lower frame 150 toward the inner side in the left-right direction. The connection frame 160 extends while curving downward as it extends toward the inner side in the left-right direction.

[0049] As shown in FIG. 1, the support base connecting portion 161 connects between a pair of connection frames 160. The support base connecting portion 161 is located below the lower frame 150 in a side view. The support base connecting portion 161 is located on the inner side in the left - right direction with respect to the pair of lower frames 150 as shown in FIG. 2. The support base connecting portion 161 is formed in a U - shape that opens forward. As shown in FIG. 3, the support base connecting portion 161 includes a regulation wall portion 165 and a pair of front protruding portions 167. The regulation wall portion 165 extends in the left - right direction. The front protruding portion 167 extends obliquely downward in front from both ends in the left - right direction of the regulation wall portion 165.

[0050] FIG. 8 is a cross - sectional view taken along the line VIII - VIII of FIG. 2. As shown in FIG. 8, a holding portion 168 is formed on the inner surface of the front end portion of the front protruding portion 167. The holding portion 168 is a concave portion that opens inward in the left - right direction in the front protruding portion 167. The holding portion 168 holds the portion of the backrest support shaft 52 that protrudes from the rear case 33. Thereby, the back frame 123 is supported so as to be rotatable about an axis O2 along the left - right direction with the backrest support shaft 52 as a fulcrum. The holding portion 168 has an insertion opening portion (opening portion) 168a that opens on the front end surface of the front protruding portion 167. The backrest support shaft 52 can be inserted into the holding portion 168 through the insertion opening portion 168a. The insertion opening portion 168a opens in the radial direction (intersection direction) of the axis O2 in a state where the backrest support shaft 52 is accommodated in the holding portion 168.

[0051] On the portion of the inner surface of the holding portion 168 that faces the circumferential direction around the axis O2, a retaining portion 170 is formed. The retaining portion 170 is an arc - shaped groove that extends in the circumferential direction around 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 in the front protruding portion 167.

[0052] Among the both side walls of the rear case 33, projections 173 are formed at portions that are opposed to the front projection 167 in the left-right direction. The projections 173 are accommodated within the retaining portion 170. The projections 173 advance and retreat from the retaining portion 170 according to the angle θ (see FIG. 1) of the back frame 123 with respect to the seat frame 120.

[0053] Here, as shown in FIG. 1, the angle θ of the back frame 123 with respect to the seat frame 120 is an angle formed by a first virtual line L1 connecting the axis O1 and the front end of the seat frame 120 and a second virtual line L2 connecting the axis O1 and the upper end of the back frame 123 in a side view. In the present embodiment, when the angle θ of the chair body 3 is at the first angle, as shown in FIG. 8, the projection 173 is accommodated within the retaining portion 170 (use position (first position)). In the use position, the projection 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 the rearward movement of the back frame 123 with respect to the backrest support shaft 52.

[0054] FIG. 9 is a cross-sectional view corresponding to FIG. 8 showing a state where the chair body 3 is 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 projection 173 has disengaged from the retaining portion 170 (assembled position). In the assembled position, the entire projection 173 is positioned within the holding portion 168, thereby releasing the engagement (contact) with the retaining portion 170. That is, in the assembled position, the movement of the back frame 123 in the radial direction (rearward) of the axis O2 with respect to the backrest support shaft 52 is permitted. As a result, the backrest support shaft 52 and the projection 173 are configured to be detachable from the holding portion 168. Note that the amount of entry of the projection 173 into the holding portion 168 in the assembled position may be larger than the amount of entry of the projection 173 into the holding portion 168 in the use position.

[0055] As shown in FIG. 6, vertical grooves 180 are formed on the front surface of the regulation wall portion 165. The vertical grooves 180 extend in the vertical direction at both left and right ends of the regulation wall portion 165 in the horizontal direction. Return stoppers (regulation portions) 181 are respectively locked in the vertical grooves 180. In the following description, among the return stoppers 181, the return stopper 181 locked in one of the vertical grooves 180 will be described.

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

[0057] The flange portion 181b is formed by expanding the diameter with respect to the shaft portion 181a at the base end portion (front end portion) of the shaft portion 181a. The flange portion 181b is close to or in contact with the rear wall portion 33a from the front. Note that a tapered surface extending obliquely upward in the front is formed on the flange portion 181b. The knob portion 181c protrudes upward from the flange portion 181b.

[0058] In the rear case 33, a positioning bolt 185 is provided at a portion located forward of the return stopper 181. The positioning bolt 185 is provided in a state of protruding into the rear case 33 from the bottom wall portion 33d of the rear case 33. The positioning bolt 185 is disposed in front of the flange portion 181b and restricts the forward movement of the return stopper 181 with respect to the rear case 33. That is, the positioning bolt 185 suppresses the return stopper 181 from detaching from the vertical groove 180.

[0059] As shown in FIG. 3, among the restricting wall portions 165, a tilting restricting portion 190 is formed at a portion located between the respective vertical grooves 180. The tilting restricting portion 190 is a recess that opens at the front surface and the lower surface of the restricting wall portion 165. When the advancing / retreating piece 74 is in the protruding position, the rear end portion of the advancing / retreating piece 74 enters the tilting restricting portion 190. When the advancing / retreating piece 74 is in the protruding position, as the back frame 123 rotates rearward, the top surface of the tilting restricting portion 190 and the advancing / retreating piece 74 come into contact with each other. Thereby, the rotation range of the back frame 123 with respect to the seat frame 120 is restricted. On the other hand, as shown in FIG. 10, when the advancing / retreating piece 74 is in the retracted position, the advancing / retreating piece 74 retreats from the tilting restricting portion 190. That is, when the advancing / retreating piece 74 is in the retracted position, the advancing / retreating piece 74 retreats from the rotation locus 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 back frame 123 abuts against a restricting portion (not shown) provided on the casing 21, whereby the rotation range is restricted. Note that the back frame 123 only needs to have a smaller rotation range when the tilting restricting portion 190 is in the protruding position than when the tilting restricting portion 190 is in the retracted position. That is, the back frame 123 may be prevented from rotating or may rotate slightly when the tilting restricting portion 190 is in the protruding position.

[0060] The tension member 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 tension member 111 is integrally fastened along the outer peripheral edges of the seat frame 120 and the back frame 123. Among the tension member 111, the portion covering the seat frame 120 constitutes the seat surface 100a. Among the tension member 111, the portion covering the back frame 123 constitutes the backrest surface 100b. Note that the tension member 111 is formed by combining stretchable synthetic resin fibers in a mesh shape. However, as long as the tension member 111 is configured to deform following the rotation of the backrest 101 with respect to the seat 100, it is not limited to a mesh shape, and for example, a cloth shape, a film shape, etc. can be adopted.

[0061] As shown in FIGS. 2, 4, and 5, an urging mechanism 200 is interposed between the seat frame 120 and the support base 12. The urging mechanism 200 urges the seat frame 120 forward. The urging mechanism 200 includes a first urging member 201, a holding member 202, and a second urging member 203.

[0062] The first urging member 201 is formed by an elastically deformable wire strung between the casing 21 and the spring housing portion 133. Specifically, with the central portion of the first urging member 201 supported by the front end portion of the case body 31, both end portions in the left-right direction extend upward and outward in the left-right direction along the inside of the front extending portion 32 as they extend forward. Both end portions in the left-right direction of the first urging member 201 enter the spring housing portion 133 through the slide allowance portion 133a.

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

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

[0065] (Usage method of the chair 1) Next, as the usage method of the chair 1 described above, the operation when reclining the chair body 3 will be described. In the following description, the state where the retractable piece 74 is in the retracted position is described as the initial state. FIG. 11 is a side view of the chair 1 showing the reclined state of the backrest 101. The chair 1 of the present embodiment constitutes a link mechanism with the support base 12 (casing 21) as a fixed link, the back frame 123 as a rotating link, and the seat frame 120 as a sliding link. Specifically, when a seated person sits on the chair body 3 and leans against the backrest 101, a rearward load acts on the chair body 3 via the backrest 101. Then, as shown in FIG. 11, the backrest 101 rotates rearward around the axis O2 with respect to the support base 12. Then, the backrest 101 rotates rearward around the axis O1 with respect to the seat 100. As a result, the seat 100 is pulled rearward as the backrest 101 rotates. At this time, since the seat 100 is configured to be movable in the front-rear direction while the vertical movement is restricted by the slider 51, the seat 100 slides rearward with respect to the support base 12 as the backrest 101 rotates. Further, since the seat engagement portion 132 extends downward as it moves rearward, the seat 100 moves downward as it moves rearward. As a result, while the entire chair body 3 moves rearward, the backrest 101 is reclined rearward. Further, when the backrest 101 is reclined, the biasing members 201 and 203 are elastically deformed as the seat 100 moves rearward. Thereby, the biasing force of the biasing mechanism 200 increases.

[0066] When the seated person stands up and the load acting on the backrest 101 is released, the seat 100 tends to move forward by the biasing force of the biasing mechanism 200. Along with this, the backrest 101 rotates forward about the axis O1 with respect to the seat 100 and also rotates forward about the axis O2 with respect to the support base 12. As a result, the chair body 3 returns to the initial state. At this time, the biasing force of the coil spring as the second biasing member 203 is added to the biasing force of the first biasing member 201 made of a wire material, so that it is not necessary to elastically deform the first biasing member 201 made of a wire material excessively large. Also, while the forward and backward movement amount of the seat 100 is set within a predetermined range, since the first biasing member 201 is located rearward by the amount of the forward and backward length of the second biasing member 203, the displacement amount of the first biasing member 201 in the forward and backward direction can be suppressed by the amount of elastic deformation of the second biasing member 203 in the forward and backward direction. From this, the aging deterioration of the first biasing member 201 can be suppressed.

[0067] Next, the operation of the chair 1 in a state where the advancing / retreating piece 74 is in the protruding position will be described. To move the advancing / retreating piece 74 to the protruding position, the operation rod 62 of the tilting adjustment mechanism 24 is rotated. Then, the rotational movement of the operation rod 62 is transmitted to the second arm 72 via the first arm 71 and is converted into a linear movement of the second arm 72 and the advancing / retreating piece 74. As a result, the advancing / retreating piece 74 slides rearward within the slide space S1. As a result, the advancing / retreating piece 74 protrudes rearward from the casing 21 and enters the tilting regulation portion 190. In this state, when an attempt is made to recline the backrest 101, the top surface of the tilting regulation portion 190 abuts on the advancing / retreating piece 74 from above, thereby restricting the rotation of the backrest 101.

[0068] (Assembly method of the chair 1) Next, as an assembly method of the chair 1, a method of assembling the chair body 3 to the support base 12 will be described. FIG. 12 is a side view of the chair 1 showing a state where the chair body 3 is in the assembling position. First, as shown in FIG. 12, with the shell 110 in the assembled 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 engaging portion 132 through the rear end opening 132a and the slit opening 132e of the seat engaging portion 132. At this time, the column portion 58 of the slider 51 enters the slit 132c, and the upper wall portion 59 enters the seat engaging portion 132.

[0069] For the spring housing portion 133, the second biasing member 203 is inserted through the rear end opening of the spring housing portion 133. Subsequently, the holding member 202 is inserted through the rear end opening of the spring housing portion 133. At this time, the outer ends in the left - right direction of the first biasing member 201 enter the slide - allowing portion 133a. Then, a screw 205 is attached to the spring housing portion 133, and the tip of the screw 205 is made to project into the spring housing portion 133. Thereby, with an initial biasing force stored in both the first biasing member 201 and the second biasing member 203, the biasing mechanism 200 is assembled in the spring housing portion 133. Thus, the seat frame 120 is assembled to the support base 12.

[0070] Subsequently, as shown in FIG. 9, the backrest frame 123 and the support base 12 are connected. Specifically, the backrest support shaft 52 is made to enter the holding portion 168 through the insertion opening 168a of the holding portion 168. Then, the backrest frame 123 is rotated to the use position. Then, when the protrusion 173 enters the retaining portion 170, the backward movement of the backrest frame 123 with respect to the backrest support shaft 52 is restricted.

[0071] Next, as shown in FIG. 6, the return stopper 181 is assembled to the casing 21. Specifically, by inserting the shaft portion 181a of the return stopper 181 into the insertion hole 33c of the rear wall portion 33a, the tip of the shaft portion 181a is made to project from the rear wall portion 33a. Then, the tip of the shaft portion 181a enters the vertical groove 180 of the backrest frame 123. Thereby, the rotation of the backrest frame 123 to the assembled position is restricted. Then, by assembling the positioning bolt 185 to the casing 21, the forward movement of the return stopper 181 is restricted.

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

[0073] (Effect) As described above, in the chair 1 of the present embodiment, in the configuration where the seat frame 120 and the backrest frame 123 are assembled to be rotatable about the first axis O1, the support base 12 includes a slider 51 that supports the seat frame 120 so as to be movable in the front-rear direction, and a backrest support shaft 52 that supports the backrest frame 123 so as to be rotatable about the second axis O2. According to this configuration, as the backrest 101 rotates about the axis O2 with respect to the support base 12, the backrest 101 (backrest frame 123) rotates about the axis O1 with respect to the seat 100 (seat frame 120), and the seat 100 slides in the front-rear direction with respect to the support base 12. Thereby, compared with the configuration in which the front end portion of the seat is lifted as the backrest rotates rearward as in the prior art, it is possible to suppress the vertical movement of the seat 100 as the backrest 101 rotates rearward. That is, as the backrest 101 rotates, the seat 100 can be smoothly moved in the front-rear direction, so that the discomfort given to the seated person during reclining can be reduced.

[0074] In the chair 1 of the present embodiment, a connecting member 121 that connects the seat frame 120 and the backrest frame 123 so as to be rotatable about the axis O1 is provided. According to this configuration, by using a connecting member 121 that is separate from the seat frame 120 and the backrest frame 123, it is easy to adjust the rotation amount and the like of the backrest frame 123 with respect to the seat frame 120 while ensuring the strength of the chair body 3.

[0075] In the chair 1 of the present embodiment, when the chair body 3 (shell 110) is in the use position, it engages with the protrusion 173 in the opening direction of the insertion opening 168a to restrict the movement of the backrest frame 123 relative to the support base 12 in the radial direction of the axis O2. When the chair body 3 is in the assembly position, it is disengaged from the protrusion 173 to allow the movement of the backrest frame 123 relative to the support base 12 in the radial direction of the axis O2. The chair is configured with a retaining portion 170. According to this configuration, with the chair body 3 in the assembly position, by approaching or separating the holding portion 168 and the backrest support shaft 52 in the radial direction of the axis O2, the backrest support shaft 52 can be attached to and detached from the holding portion 168 through the insertion opening 168a. On the other hand, with the backrest support shaft 52 accommodated in the holding portion 168, by setting the chair body 3 to the use position, it is possible to suppress the backrest support shaft 52 from detaching from the holding portion 168 through the insertion opening 168a. Thereby, even if the seat 100 and the backrest 101 are integrally combined, the assemblability can be improved.

[0076] In the chair 1 of the present embodiment, when the chair body 3 is in the use position, a return stopper 181 that engages with the backrest frame 123 to restrict rotation to the assembly position around the axis O1 is detachably provided on the support base 12. According to this configuration, after the backrest frame 123 is assembled to the support base 12, it is possible to restrict the backrest frame 123 from returning to the assembly position. Thereby, both the assemblability and the reliability after assembly can be ensured.

[0077] In the chair 1 of the present embodiment, the seat engaging portion 132 opens rearward and has a slit 132c extending in the front-rear direction, and the slider 51 is supported so as to be movable in the front-rear direction within the slit 132c. According to this configuration, the slider 51 can be inserted into the slit 132c through the rear end opening 132a of the seat engaging portion 132. Thereby, the assemblability of the seat frame 120 to the support base 12 can be improved.

[0078] (Other Modification Examples) As described above, the preferred embodiments of the present disclosure have been explained, but the present disclosure is not limited to these embodiments. Additions, omissions, substitutions, and other changes to 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 appended claims. In the above-described embodiment, the configuration in which the seat frame 120 and the back frame 123 are rotatably connected via the connecting member 121 has been described, but the present disclosure is not limited to this configuration. The connecting member may have a configuration having only a pivot portion that rotatably connects the seat frame 120 and the back frame 123. Further, the connecting member may have a configuration that can be bent. Furthermore, the chair body 3 may have a configuration that does 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 bendable. In the above-described embodiment, the configuration including the first biasing member 201 made of a wire rod and the second biasing member 203 made of a coil spring as the biasing mechanism 200 interposed between the seat frame 120 and the casing 21 has been described, but the present disclosure is not limited to this configuration. The biasing mechanism 200 may have a configuration including 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 disclosure is not limited to this configuration. The retaining portion 170 may be provided at a position different from the holding portion 168. In the above-described embodiment, the block-shaped slider 51 is adopted as the first support portion, and the configuration in which the slit 132c is formed in the seat frame 120 has been described, but the present disclosure is not limited to this configuration. The first support portion only needs to support the seat frame 120 so as to be movable in the front-rear direction. In this case, the first support portion 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 portion and the seat frame 120 may be a combination of a rail and a roller or the like.

[0080] In the above-described embodiment, the backrest support shaft 52 was adopted as the second support portion, and the configuration in which the holding portion 168 was formed in the back frame 123 was described. 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 by the shaft may be provided in the second support portion. In the above-described embodiment, the configuration in which the return stopper 181 is provided on the support base 12 was described. However, the present invention is not limited to this configuration. The return stopper 181 may be detachably provided on the back frame 123 and engage with the support base 12. In the above-described embodiment, the case where the seat frame 120 constitutes the outer shell of the seat 100 and the back frame 123 constitutes the outer shell of the backrest 101 among the chair main body 3 (shell 110) was described. However, the outer shell of the chair main body 3 may be formed by a first member that constitutes a part of the outer shell of the seat 100 and a second member that constitutes a part of the outer shell of the backrest 101. For example, the seat frame 120 may constitute the front half portion of the seat 100, and the back frame 123 may constitute the rear half portion 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 constitutes a region of 1 / 2 or more with respect to 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 not departing from the gist of the present disclosure, it is possible to appropriately replace the components in the above-described embodiment with well-known components, and the above-described various modified examples may be appropriately combined.

Description of Reference Numerals

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

Claims

1. A support structure, a first member extending in the front-rear direction and constituting at least a part of the seat, and a chair body having a second member provided at the 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 to constitute at least a part of the backrest, wherein the support structure, includes a first support portion that supports the first member movably in the front-rear direction in front of the first axis, and a second support portion that supports the second member rotatably about a second axis along the left-right direction below the first axis, the chair body is configured to be rotatable between a first position where an angle formed by the first member and the second member about the first axis is a first angle, and a second position where an angle formed by 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, has an opening that opens in a crossing direction intersecting the second axis and into which the second support portion can be inserted, and a holding portion that holds the second support portion, and a retaining portion that engages with the support structure in the crossing direction when the chair body is in the first position to restrict movement of the second member in the crossing direction with respect to the support structure, and disengages from the support structure when the chair body is in the second position to allow movement of the second member in the crossing direction with respect to the support structure.

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

3. On one of the second member and the support structure, when the chair body is in the first position, a restricting portion is detachably provided which engages with the other member of the second member and the support structure to restrict rotation of the chair body about the first axis to the second position. The chair according to claim 1 or claim 2.

4. 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 extending in the front-rear direction is formed. The chair according to any one of claims 1 to 3, wherein the first support portion is configured to be movable in the front-rear direction within the slit.

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