Seat and chair

Abstract

To provide a seat and a chair capable of suppressing falling of a nut.SOLUTION: A seat in one embodiment of the invention comprises: a seat body; and a nut holding part 80. The nut holding part 80 comprises: a nut insertion hole 90 for opening a nut storage space 83 in a lateral direction; and a bolt insertion hole 91 for opening the nut storage space 83 downward. On the nut holding part 80, on a position provided on outside in a lateral direction with respect to the bolt insertion hole 91, there is formed a regulation part 94 which comprises: an engagement plane 96 for being engaged to the nut 82 in a lateral direction in a state of storing the nut 82 in the nut storage space 82, and for regulating movement of the nut 82 in the lateral direction with respect to the nut holding part 80.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a seat and a chair.

Background Art

[0002] Patent Document 1 below discloses a so-called nude shell type chair in which a backrest and a seat do not have a cushion material. In this type of chair, a tunnel-shaped nut holding portion is formed on the lower surface of the seat. The seat is connected to the support structure by fastening a bolt to the nut held in the nut holding portion.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the configuration of Patent Document 1 described above, since the nut holding portion is formed in a tunnel shape, the nut may fall off from the nut holding portion when the seat is assembled or when the bolt is loose.

[0005] An object of the present invention is to provide a seat and a chair capable of suppressing the dropout of nuts.

Means for Solving the Problems

[0006] In order to achieve the above object, a seat according to an aspect of the present invention includes a support plate having a load support surface facing upward, and a nut holding portion that defines a nut accommodation space for accommodating a nut between a lower surface of the support plate. The nut holding portion has a nut insertion opening that opens the nut accommodation space in a first direction among surface directions intersecting in the vertical direction and allows the nut to be inserted, and a bolt insertion opening that opens the nut accommodation space on one side in the vertical direction and allows a shaft portion of a bolt to be inserted through a support structure. In a portion of the nut holding portion that is closer to the nut insertion opening than the bolt insertion opening in the first direction, the nut has a locking surface that is locked to the nut in the first direction in a state where the nut is accommodated in the nut accommodation space, and a restricting portion is formed to restrict movement of the nut in the first direction with respect to the nut holding portion.

[0007] According to this aspect, when the nut is locked to the locking surface, movement of the nut in the first direction with respect to the nut holding portion is restricted. Thereby, for example, at the time of assembly or when the bolt is loosened, it is possible to suppress the nut from falling out of the nut accommodation space. In this case, for example, compared with the case where the nut is integrally incorporated into the nut holding portion by insert molding or the like, cost reduction can be achieved.

[0008] In the seat of the above aspect, the nut holding portions may be arranged at intervals in a second direction intersecting the first direction among the surface directions, project from the support plate to the one side in the vertical direction, and include ribs that connect the adjacent nut holding portions in the second direction. According to this aspect, the rigidity of the nut holding portion can be ensured by the ribs. That is, since the load acting on the outer peripheral portion of the seat due to the seating load can be dispersed to the nut holding portion and the ribs, it is possible to suppress the load in the direction of separating from the bolt from acting locally on the nut via the nut holding portion. Thereby, even if the outer peripheral portion of the seat tends to be displaced upward by the seating load mainly acting on the central portion of the seat, distortion of the nut holding portion and the like can be suppressed. As a result, the connection strength between the seat and the support structure can be ensured.

[0009] In the seat according to the above aspect, in the nut holding portion, a communication port is formed that opens the nut accommodation space to one side in the vertical direction and communicates between the bolt insertion port and the nut insertion port in the first direction. The restricting portion may bulge inside the communication port in a second direction that intersects the first direction among the surface directions with the locking surface facing the bolt insertion port in the first direction. According to this aspect, when the nut holding portion is formed by injection molding, the core pin for forming the communication port does not cross over the locking surface. As a result, while maintaining the ease of mold release, the protruding amount from the communication port of the restricting portion can be ensured. Therefore, while suppressing a decrease in manufacturing efficiency due to the addition of the restricting portion, it becomes easier to restrict the movement of the nut by the restricting portion.

[0010] In the seat according to the above aspect, in a portion of the nut holding portion that is closer to the nut insertion port than the bolt insertion port in the first direction, a through hole is formed that opens the nut accommodation space to one side in the vertical direction. The restricting portion may bulge into the nut accommodation space with the locking surface continuous with the inner peripheral surface of the through hole. According to this aspect, the restricting portion can be formed in a portion defined by the core pin for forming the through hole and the core pin for forming the nut accommodation space. As a result, the restricting portion can be integrally formed during the molding of the seat, so a decrease in manufacturing efficiency due to the addition of the restricting portion can be suppressed.

[0011] In the seat according to the above aspect, the restricting portion is configured to be elastically deformable, and a crossing surface that the nut can cross over may be formed on a surface of the restricting portion that faces the bolt insertion port in the first direction. According to this aspect, after the nut crosses over the top portion that is the boundary between the locking surface and the crossing surface, the restricting portion restores and deforms. As a result, it becomes easier to ensure the locking allowance between the nut and the locking surface. Consequently, the movement of the nut in the first direction can be reliably restricted by the restricting portion.

[0012] The chair according to an aspect of the present invention includes the seat according to any of the above aspects, and the support structure connected to the seat, wherein the bolt inserted through the bolt insertion hole is screwed to the nut accommodated in the nut accommodation space. According to this aspect, a low-cost chair with excellent assemblability can be provided.

Effects of the Invention

[0013] According to each of the above aspects, the dropout of the nut can be suppressed.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0015] Next, embodiments of the present invention will be described with reference to the drawings. In each of 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. represent not only exactly such arrangements, but also states in which they are relatively displaced with tolerances or at angles and distances that provide the same function. Also, the front-back, up-down, left-right directions in the following description indicate the directions as seen from the seated person.

[0016] (First Embodiment) [Chair 1] FIG. 1 is a perspective view of chair 1. As shown in FIG. 1, chair 1 according to the present embodiment is a so-called nude shell type chair in which the backrest 2 and the seat 3 do not have cushioning materials. Specifically, chair 1 is configured such that the above-described backrest 2 and seat 3 are supported by a support structure 4.

[0017] [Support Structure 4] FIG. 2 is an exploded perspective view of seat 3 and support structure 4. As shown in FIG. 2, support structure 4 includes a pair of left and right legs 10, a rear connecting rod 11, a front frame 12, and side frames 13. Each leg 10 is formed by bending a pipe material made of metal or the like into a trapezoidal frame shape when viewed from the left-right direction (side view). Specifically, leg 10 includes a front leg 21, a rear leg 22, a lower connecting rod 23, an upper connecting rod 24, and a backrest support portion 25.

[0018] Front leg 21 extends gradually forward as it extends downward. Lower connecting rod 23 extends rearward from the lower end portion of front leg 21. Lower connecting rod 23 is grounded to the floor surface F (see FIG. 1) via a grounding cap 26. Rear leg 22 extends upward from the rear end portion of lower connecting rod 23. In the present embodiment, rear leg 22 is inclined forward as it extends upward. Upper connecting rod 24 extends rearward from the upper end portion of front leg 21.

[0019] The backrest support portion 25 is configured such that a portion bent upward from the rear end portion of the upper connecting rod 24 and a portion protruding upward from the upper end portion of the rear leg 22 among the pipe materials constituting the leg body 10 are joined together by welding or the like.

[0020] The rear connecting rod 11 bridges the rear end portions of the upper connecting rods 24 in each leg body 10. The rear connecting rod 11 has an arcuate shape that is convex rearward when viewed from above (in plan view). Both the left and right end portions of the rear connecting rod 11 are joined to the corresponding upper connecting rods 24 by welding or the like.

[0021] The front frame 12 is configured such that a plate material such as metal extends along the left - right direction. The front frame 12 bridges the corners formed by the upper connecting rod 24 and the front leg 21 in each leg body 10. Both the left and right end portions of the front frame 12 are joined to the corresponding corners by welding or the like. In the present embodiment, the front frame 12 extends downward as it goes forward following the corner formed by the upper connecting rod 24 and the front leg 21. A bulging portion 28 that is recessed upward is formed in the front frame 12. A mounting hole 29 that penetrates vertically is formed in the top wall of the bulging portion 28. Note that a plurality of bulging portions 28 are provided in the front frame 12 at intervals in the left - right direction.

[0022] The side frame 13 projects inward in the left - right direction (toward the center of the chair 1) from the upper connecting rod 24 in each leg body 10. The side frame 13 is configured such that a plate material such as metal extends along the front - rear direction (the second direction among the surface directions).

[0023] Figure 3 is a cross - sectional view corresponding to the line III - III in Figure 5. Figure 4 is a cross - sectional view corresponding to the line IV - IV in Figure 5. As shown in Figures 3 and 4, the side frame 13 includes an inclined portion 31, a mounting piece 32, and an upright piece 33. The inclined portion 31 slopes gradually downward as it extends inward in the left - right direction (the first direction among the plane directions). The outer end portions of the inclined portion 31 in the left - right direction are joined to the upper connecting rod 24 by welding or the like. Note that the side frame 13 is also joined to the above - mentioned rear connecting rod 11 and the front frame 12 by welding or the like at both the front and rear end edges. In the present embodiment, the rear connecting rod 11, the front frame 12, and the side frame 13 constitute a seat support portion 34 in a rectangular frame shape in plan view.

[0024] The mounting piece 32 extends inward in the left - right direction from the inclined portion 31. In the present embodiment, the mounting piece 32 extends parallel to the floor surface F (see FIG. 1). As shown in FIG. 3, a bulging portion 35 that bulges upward is formed on the mounting piece 32. A mounting hole 36 that penetrates in the vertical direction is formed in the top wall of the bulging portion 35. Note that a plurality of bulging portions 35 are provided at intervals in the front - rear direction on the mounting piece 32.

[0025] The standing piece 33 protrudes upward from the inner end portion of the mounting piece 32 in the left - right direction. In the illustrated example, the upper end edge of the standing piece 33 is set to the same height as the outer end portion of the inclined portion 31 in the left - right direction.

[0026] <Backrest 2> As shown in FIG. 1, the backrest 2 is supported by the backrest support portion 25. The backrest 2 supports the waist, back, etc. of the seated person from behind. In the present embodiment, the backrest 2 is formed in a plate shape by injection - molding a resin material. Specifically, the backrest 2 has a convex arc shape facing backward in plan view and a convex arc shape facing forward in side view.

[0027] The backrest 2 is supported by the support structure 4 by inserting the above - mentioned backrest support portions 25 separately into leg - accommodating portions (not shown) formed at both ends in the left - right direction. Note that the backrest support portion 25 may be fixed to the backrest 2 by screws or the like in a state of being accommodated in the leg - accommodating portion, or may be fixed to the backrest 2 by being press - fitted into the leg - accommodating portion.

[0028] <Seat 3> As shown in FIG. 2, the seat 3 is supported from below by the support structure 4. Specifically, the seat 3 includes a seat body (support plate) 51 and a connecting portion 52. The seat 3 is integrally formed by injection molding a resin material. Therefore, the seat 3 is configured to be elastically deformable. The seat body 51 is formed in a plate shape with the vertical direction as the thickness direction. The seat body 51 supports the buttocks and thighs of the seated person from below when seated. That is, the upper surface of the seat body 51 constitutes the seating surface (load support surface) 53. Specifically, the seat body 51 includes a main support portion 55, a front continuous portion 56, and a rear continuous portion 57.

[0029] The main support portion 55 covers the above-described seat support portion 34 from above. The main support portion 55 is formed in a rectangular shape in plan view. The main support portion 55 has a downwardly convex arc shape in a cross-sectional view orthogonal to the front-rear direction and a cross-sectional view orthogonal to the left-right direction. A rear concave portion 60 is formed at the rear end portion of the main support portion 55. The rear concave portion 60 is recessed upward from the lower surface of the main support portion 55 and extends over the entire left-right direction of the main support portion 55. The upper end portion of the above-described rear connecting rod 11 is accommodated in the rear concave portion 60 and is in proximity to or in contact with the inner surface of the rear concave portion 60 from below.

[0030] The front continuous portion 56 is continuous with the front edge of the main support portion 55. Specifically, in a side view, the front continuous portion 56 extends while curving downward as it goes forward following the corner formed by the upper connecting rod 24 and the front leg 21. A front rib 61 extending in the front-rear direction is formed on the lower surface (back surface) of the front continuous portion 56. The front ribs 61 face each other in the left-right direction to form a rib pair 62. The rib pairs 62 are arranged in the left-right direction with an interval wider than the interval between the front ribs 61 constituting the rib pair 62. The lower end edge of each rib 61 is in proximity to or in contact with the above-described front frame 12. However, the shape, pitch, etc. of the front rib 61 can be changed as appropriate.

[0031] The rear continuous part 57 is continuous with the rear edge of the main support part 55. Specifically, in a side view, the rear continuous part 57 extends while curving upward as it goes rearward following the corner formed by the upper connecting rod 24 and the backrest support part 25. On the lower surface (rear surface) of the rear continuous part 57, a first rear rib 65 and a second rear rib 66 are formed.

[0032] The first rear rib 65 is arranged at intervals in the left - right direction at the central part in the left - right direction of the rear continuous part 57. The second rear rib 66 extends along the front end part and both end parts in the left - right direction of the rear continuous part 57. However, the shape, pitch, etc. of each rear rib 65, 66 can be appropriately changed.

[0033] As shown in FIG. 3, lateral recesses 67 are formed at both end parts in the left - right direction of the seat body 51. The lateral recesses 67 are open downward and outward in the left - right direction. The lateral recesses 67 extend throughout the front - rear direction in the seat body 51 (front continuous part 56, main support part 55, and rear continuous part 57). The part from the corner formed by the upper connecting rod 24 and the front leg 21 to the corner formed by the upper connecting rod 24 and the backrest support part 25 is accommodated in the lateral recess 67 and is in a state of being close to or in contact with the inner surface of the lateral recess 67 from below.

[0034] As shown in FIG. 2, the connecting part 52 includes a lateral connecting part 70 and a front connecting part 71. The lateral connecting parts 70 are respectively formed at both end parts in the left - right direction on the lower surface of the main support part 55. Specifically, the lateral connecting parts 70 extend in the front - rear direction at positions overlapping with the side frames 13 (mounting pieces 32) in a plan view on the lower surface of the main support part 55. Each lateral connecting part 70 has a bilaterally symmetric configuration. Therefore, hereinafter, among the pair of left - right lateral connecting parts 70, the right - hand lateral connecting part 70 will be described as an example.

[0035] FIG. 5 is a partial bottom view of the seat 3. As shown in FIG. 5, the lateral connecting part 70 includes a nut holding part 80 and a rib 81. The nut holding portions 80 are arranged at the central portion and the rear end portion in the front-rear direction of the lower surface of the main support portion 55. Each nut holding portion 80 has the same configuration. Therefore, hereinafter, the nut holding portion 80 located at the central portion will be described as an example.

[0036] As shown in FIGS. 3 and 5, the nut holding portion 80 is formed in a box shape that opens to the outside (right side) in the left-right direction. The nut holding portion 80 defines a nut accommodation space 83 for accommodating the nut 82 between the lower surface of the main support portion 55.

[0037] FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 3. As shown in FIG. 6, the peripheral wall 84 of the nut holding portion 80 is formed in a C shape that opens toward the outside in the left-right direction in a cross-sectional view orthogonal to the up-down direction. Specifically, the peripheral wall 84 includes a front wall 85 and a rear wall 86, and a connecting wall 87 that bridges between the front wall 85 and the rear wall 86. In the example of FIG. 6, the front wall 85 and the rear wall 86 project on both sides in the left-right direction with respect to the connecting wall 87.

[0038] FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 5. As shown in FIGS. 5 and 7, the bottom wall 88 of the nut holding portion 80 closes the lower end opening of the peripheral wall 84. A positioning recess 89 that is recessed upward is formed on the lower surface of the bottom wall 88. The positioning recess 89 is formed in a tapered shape in which the width in the front-rear direction gradually decreases as it goes upward. The bulging portion 35 described above is accommodated in the positioning recess 89. The top wall of the bulging portion 35 is in contact with the top wall of the positioning recess 89 from below. In the illustrated example, the positioning recess 89 is also continuous with the above-described connecting wall 87 and is formed over the entire length in the left-right direction in the nut holding portion 80. Note that the nut holding portion 80 may be configured not to have the positioning recess 89.

[0039] As shown in FIG. 3, in the nut holding portion 80, the outer opening in the left - right direction constitutes a nut insertion port 90 into which the nut 82 can be inserted. The nut insertion port 90 opens the nut accommodation space 83 to the outside in the left - right direction. In the present embodiment, the height in the up - down direction of the nut accommodation space 83 gradually decreases as it goes inward in the left - right direction (as it moves away from the nut insertion port 90). In the lower surface of the main support portion 55, in the portion located outside the nut holding portion 80 in the left - right direction, a relief portion 93 that is recessed upward is formed. The relief portion 93 gradually becomes shallower as it goes in the left - right direction.

[0040] As shown in FIG. 6, in the bottom wall 88 (the top wall of the positioning recess 89), in the portion that overlaps with the above - mentioned mounting hole 36 in a plan view, a bolt insertion port 91 is formed. The bolt insertion port 91 opens the nut accommodation space 83 downward. Note that the above - mentioned positioning recess 89 may be formed at a position different from the bolt insertion port 91.

[0041] In the bottom wall 88, in the portion located outside the bolt insertion port 91 in the left - right direction, a communication port 92 is formed. The communication port 92 penetrates the bottom wall 88 in the up - down direction and extends in the left - right direction. The communication port 92 communicates the nut insertion port 90 and the bolt insertion port 91 in the left - right direction. That is, the communication port 92 opens on the outer edge in the left - right direction of the bottom wall 88.

[0042] On the inner peripheral edges of the communication port 92 that face each other in the front - rear direction, restriction portions 94 that bulge inward in the front - rear direction (the side where the inner peripheral edges face each other) are respectively formed. In a plan view, the restriction portion 94 is formed in a triangular shape that bulges inward in the front - rear direction as it goes from both sides in the left - right direction toward the central portion. Specifically, the restriction portion 94 has a locking surface 96 that continues inward in the left - right direction with respect to the top portion 95 and a climbing - over surface 97 that continues outward in the left - right direction with respect to the top portion 95.

[0043] The locking surface 96 is inclined outward in the front-rear direction as it faces inward in the left-right direction. That is, the locking surface 96 faces the inner side in the left-right direction (bolt insertion port 91). Note that the locking surface 96 only needs to be configured such that its normal direction has at least a component in the left-right direction and no component in the up-down direction.

[0044] The overstep surface 97 is inclined outward in the front-rear direction as it faces outward in the left-right direction. Therefore, the opening width in the front-rear direction at the communication port 92 gradually decreases as it faces outward in the left-right direction and then gradually expands as it further faces outward in the left-right direction. In the illustrated example, the length of the locking surface 96 in the left-right direction is shorter than the length of the overstep surface 97 in the left-right direction. Also, the inclination angles of the locking surface 96 and the overstep surface 97 with respect to the left-right direction may be equal to or different from each other. Further, in the present embodiment, a configuration in which the restricting portion 94 is formed over the entire front-rear direction of the inner peripheral edge of the communication port 92 has been described, but the present invention is not limited to this configuration, and the restricting portion 94 may be formed on a part of the inner peripheral edge of the communication port 92.

[0045] Incidentally, the nut insertion port 90 is formed following the molding surface (outer surface) of the first core pin that can advance and retreat in the left-right direction during the injection molding of the seat 3. Also, the bolt insertion port 91 and the communication port 92 are formed following the molding surface (outer surface) of the second core pin that can advance and retreat in the up-down direction during the injection molding of the seat 3. In this case, in the present embodiment, since the restricting portion 94 bulges from the inner peripheral edge of the communication port 92, the thickness direction of the restricting portion 94 is formed in a state along the advancing and retreating direction of the second core pin.

[0046] As shown in FIG. 5, the rib 81 protrudes downward from the main support portion 55. Specifically, the rib 81 includes a connection rib 100, an extension rib 101, and an auxiliary rib 102. The connection rib 100 connects the nut holding portions 80 adjacent to each other in the front-rear direction. The connection rib 100 includes a first connection portion 110 and a second connection portion 111 provided at intervals in the left-right direction.

[0047] The first connecting portion 110 is located inside the second connecting portion 111 in the left - right direction. The first connecting portion 110 linearly connects the inner ends in the left - right direction between the front wall 85 of the nut holding portion 80 located at the rear end in the front - rear direction and the rear wall 86 of the nut holding portion 80 located at the central portion in the front - rear direction among the respective nut holding portions 80. The second connecting portion 111 is located outside the first connecting portion 110 in the left - right direction. The second connecting portion 111 connects the outer ends in the left - right direction between the front wall 85 of the nut holding portion 80 located at the rear end in the front - rear direction and the rear wall 86 of the nut holding portion 80 located at the central portion in the front - rear direction among the respective nut holding portions 80. Among the second connecting portion 111, the outer surface 111a facing the outer side in the left - right direction is arranged flush with the opening surface of the nut insertion port 90 (the outer end surface in the left - right direction in the nut holding portion 80). However, the outer surface 111a of the second connecting portion 111 may be arranged shifted in the left - right direction with respect to the opening surface of the nut insertion port 90.

[0048] In the illustrated example, the lower end surfaces of the connecting portions 110 and 111 are arranged flush with the lower end surfaces of the front wall 85 and the rear wall 86. Therefore, the lower end surfaces of the connecting portions 110 and 111 are close to or in contact with the mounting piece 32 from above. In this case, the lower end surfaces of the connecting portions 110 and 111 are located below the top wall of the positioning recess 89. However, the lower end surfaces of the connecting portions 110 and 111 may be higher or lower than the front wall 85 and the rear wall 86.

[0049] The extension rib 101 includes a first extension portion 115 and a second extension portion 116 provided at intervals in the left - right direction, and a bridging portion 117 bridging between the front end portions of the respective extension portions 115 and 116.

[0050] The first extension portion 115 extends forward from the outer end in the left - right direction on the front wall 85 of the nut holding portion 80 located at the central portion in the front - rear direction. The first extension portion 115 is located on the same straight line as the above - mentioned first connecting portion 110. The second extension portion 116 extends forward from the inner end portion in the left - right direction on the front wall 85 of the nut holding portion 80 located at the central portion in the front - rear direction. Among the second extension portions 116, the outer surface 116a facing the outer side in the left - right direction is arranged flush with the opening surface of the nut insertion port 90. The bridging portion 117 extends linearly along the left - right direction.

[0051] The auxiliary rib 102 protrudes inward in the left - right direction from the first connecting portion 110 and the first extension portion 115 among the ribs 81. A plurality of auxiliary ribs 102 are arranged at intervals in the front - rear direction. As shown in FIG. 4, the lower end surface of the auxiliary rib 102 is formed as an inclined surface that extends upward as it goes inward in the left - right direction. The inner end surface in the left - right direction of the auxiliary rib 102 is close to or in contact with the above - mentioned upright piece 33 from the outer side in the left - right direction. That is, the auxiliary rib 102 also has a function of positioning the side connecting portion 70 in the left - right direction with respect to the side frame 13.

[0052] As shown in FIG. 2, the front connecting portion 71 includes a nut holding portion 120 and a rib 121. Regarding the configuration similar to the above - mentioned side connecting portion 70 in the front connecting portion 71, the description will be omitted as appropriate. The nut holding portion 120 is formed in a box shape that opens to the outer side in the left - right direction, similar to the above - mentioned nut holding portion 80.

[0053] The rib 121 protrudes downward from the main support portion 55. Specifically, the rib 121 includes a connecting rib 125 and an auxiliary rib 126. The connecting ribs 125 extend parallel to each other in the left - right direction at intervals in the front - rear direction. Each connecting rib 125 connects adjacent nut holding portions 120 in the left - right direction.

[0054] The auxiliary rib 126 extends in the front - rear direction and connects between the connecting ribs 125. A plurality of auxiliary ribs 126 are arranged at intervals in the left - right direction. In the illustrated example, the auxiliary ribs 126 are arranged at the same pitch as the above - mentioned front rib 61.

[0055] As shown in FIGS. 6 and 7, the above-described connecting portion 52 is fixed to the seat support portion 34 by a nut 82 and a bolt 140. In the following description, the fixing portion between the side connecting portion 70 and the side frame 13 will be described as an example. The nut 82 is a so-called T-nut. Specifically, the nut 82 includes a cylindrical portion 135 extending in the vertical direction and a flange portion 136 protruding from the upper end edge of the cylindrical portion 135.

[0056] The lower end portion of the cylindrical portion 135 is held in the above-described bolt insertion hole 91. A female thread portion is formed on the inner peripheral surface of the cylindrical portion 135. The cylindrical portion 135 is configured to be capable of being locked (proximated or abutted) against the locking surface 96 from the inner side in the left-right direction within the bolt insertion hole 91. Thereby, the movement of the nut 82 in the outer side in the left-right direction with respect to the nut holding portion 80 is restricted. Note that the lower end surface of the cylindrical portion 135 is located at the same level as or above the lower end opening edge of the bolt insertion hole 91.

[0057] The flange portion 136 protrudes from the upper end portion of the cylindrical portion 135 (the portion located within the nut accommodation space 83) to both the front and rear sides. The flange portion 136 is proximated or abutted against the connection wall 87 of the nut holding portion 80 in the left-right direction. Thereby, the rotation of the nut 82 with respect to the nut holding portion 80 is restricted.

[0058] The bolt 140 is inserted downward into the bolt insertion hole 91 through the above-described mounting hole 36. The shaft portion of the bolt 140 is screwed to the cylindrical portion 135 within the bolt insertion hole 91. Thereby, the seat 3 is fixed to the support structure 4. Note that a part of the head of the bolt 140 is accommodated in the bulging portion 35.

[0059] <Assembly method of the seat 3> To assemble the seat 3 to the support structure 4, first assemble the nut 82 to the nut holding portion 80. Specifically, with the cylindrical portion 135 facing the communication port 92 and the flange portion 136 facing the nut insertion port 90, the nut 82 is pushed into the nut accommodation space 83 from the outer side in the left - right direction. Then, as the cylindrical portion 135 slides over the over - coming surface 97 and moves inward in the left - right direction, the restricting portion 94 elastically deforms outward in the front - rear direction. As a result, the communication port 92 is expanded. After that, when the cylindrical portion 135 crosses over the top portion 95, the restricting portion 94 restores its deformation. Thereby, with the lower end portion of the cylindrical portion 135 held within the bolt insertion port 91, the nut 82 (flange portion 136) is accommodated within the nut accommodation space 83. Note that the communication port 92 only needs to have the opening width in the front - rear direction at least at the top portion 95 be narrower than the outer diameter of the cylindrical portion 135. That is, the opening width of the outer opening portion in the left - right direction of the communication port 92 may be wider or narrower than the outer diameter of the cylindrical portion 135.

[0060] Next, place the seat 3 on the seat support portion 34. At this time, place the seat 3 so that the corresponding nut holding portion 80 (bolt insertion port 91) and the mounting hole 36 overlap in plan view. Thereby, the lower end surfaces of the nut holding portion 80 and the rib 81 approach or contact the upper surface of the mounting piece 32 from above, and the upper end surface of the standing piece 33 approaches or contacts the lower surface of the main support portion 55 from below. At this time, the bulging portion 35 is accommodated within the concave portion 89 of the nut holding portion 80, and the auxiliary rib 126 and the standing piece 33 are close to or in contact with each other in the left - right direction. Therefore, in the state before fixing the seat 3 to the support structure 4, the positioning of the seat 3 with respect to the support structure 4 in the front - rear direction and the left - right direction can be performed.

[0061] Subsequently, insert the bolt 140 from below into the mounting hole 36 and the bolt insertion port 91 to screw the bolt 140 to the cylindrical portion 135. Thereby, the seat 3 is fixed to the support structure 4.

[0062] Thus, in the present embodiment, in the nut holding portion 80, a regulating portion 94 having a locking surface 96 that is locked to the nut 82 (cylindrical portion 135) in the left - right direction is formed in a portion located outside the bolt insertion port 91 in the left - right direction. According to this configuration, when the nut 82 is locked to the locking surface 96, the movement of the nut 82 in the left - right direction outside the nut holding portion 80 is restricted. Thereby, for example, when assembling or when the bolt 140 becomes loose, it is possible to prevent the nut 82 from falling out of the nut accommodation space 83. In this case, cost reduction can be achieved compared to, for example, the case where the nut is integrally incorporated into the nut holding portion by insert molding or the like.

[0063] In the present embodiment, the nut holding portions 80 adjacent to each other in the front - rear direction are connected by ribs 81 (connection ribs 100). According to this configuration, the rigidity of the entire side connection portion 70 can be ensured. That is, since the load acting on the outer peripheral portion of the seat 3 due to the seating load can be dispersed over the entire side connection portion 70, it is possible to suppress the local action of the load in the direction (upward) separating from the bolt 140 on the nut 82 via the nut holding portion 80. Thereby, even if the outer peripheral portion of the seat body 51 tends to be displaced upward due to the seating load mainly acting on the central portion of the seat 3, distortion of the nut holding portion 80 and the like can be suppressed. As a result, the connection strength between the seat 3 and the support structure 4 can be ensured.

[0064] In the present embodiment, the regulating portion 94 bulges inside the communication port 92, and the locking surface 96 of the regulating portion 94 faces the left - right direction. According to this configuration, when the nut holding portion 80 is formed by injection molding, the second core pin for forming the communication port 92 does not ride over the locking surface 96. Thereby, while maintaining the ease of mold release, the protruding amount of the regulating portion 94 from the communication port 92 can be ensured. Therefore, while suppressing a decrease in manufacturing efficiency due to the addition of the regulating portion 94, it becomes easier to restrict the movement of the nut 82 by the regulating portion 94.

[0065] In the present embodiment, the restricting portion 94 is configured to be elastically deformable, and an overhanging surface 97 over which the nut 82 can climb is formed on the surface of the restricting portion 94 facing the outer side in the left-right direction. According to this configuration, after the nut 82 climbs over the top portion 95 which is the boundary portion between the locking surface 96 and the overhanging surface 97, the restricting portion 94 restores and deforms. As a result, it becomes easier to secure the locking margin between the nut 82 and the locking surface 96. Consequently, the movement of the nut 82 outward in the left-right direction can be reliably restricted by the restricting portion 94.

[0066] Since the chair 1 of the present embodiment includes the seat 3 described above, a low-cost chair 1 with excellent assemblability can be provided.

[0067] (Second Embodiment) FIG. 8 is a partial bottom view of the seat 3 according to the second embodiment. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 10 is a cross-sectional view taken along line X-X in FIG. 9. The second embodiment according to the present invention is different from the above-described embodiment in that a so-called plate nut is adopted for the nut 210. In the nut holding portion 80 shown in FIGS. 8 to 10, an overhanging portion (an inner overhanging portion 202 and an outer overhanging portion (through hole) 203) is continuous with the bolt insertion port 200. The bolt insertion port 200 is formed, for example, in a hexagonal shape in plan view. Note that the opening width of the bolt insertion port 200 in the front-rear direction is narrower than the width of the nut 210 in the front-rear direction. Also, the shape of the bolt insertion port 200 in plan view can be appropriately changed within a range where the bolt 140 can be inserted.

[0068] The inner overhanging portion 202 projects inward in the left-right direction from the bolt insertion port 200. The inner overhanging portion 202 is formed in a rectangular shape in plan view. The outer protruding portion 203 protrudes outward in the left - right direction from the bolt insertion opening 200. The outer protruding portion 203 is formed in a rectangular shape in plan view. Note that the opening width in the left - right direction of the entire bolt insertion opening 200 and each protruding portion 202, 203 is wider than the width in the left - right direction of the nut 210. However, the nut holding portion 80 may be configured without the inner protruding portion 202 as long as the outer edge in the left - right direction of the outer protruding portion 203 is located outside the nut 210 in the left - right direction.

[0069] As shown in FIG. 9, the restricting portion 205 of the present embodiment bulges upward from a portion of the bottom wall 88 that is located outside the bolt insertion opening 200 in the left - right direction. The restricting portion 205 is formed in a triangular shape in side view. Specifically, the restricting portion 205 has a locking surface 206 and a climbing - over surface 207.

[0070] The locking surface 206 is formed flush with the surface of the inner surface of the outer protruding portion 203 that is located outside in the left - right direction. Therefore, the locking surface 206 faces the inside in the left - right direction outside the bolt insertion opening 200 in the left - right direction. In the present embodiment, the normal direction of the locking surface 206 coincides with the left - right direction. However, the normal direction of the locking surface 206 may be configured to have at least a component in the left - right direction and no component in the up - down direction. The climbing - over surface 207 extends downward as it goes from the upper end of the locking surface 206 toward the outside in the left - right direction.

[0071] As described above, the nut 210 of the present embodiment is a so - called plate nut. Specifically, the nut 210 is formed in a rectangular shape in plan view. In the nut 210, the outer edges in the left - right direction are in proximity to or in contact with the locking surface 206 from the inside in the left - right direction. Thereby, the movement of the nut 210 inward in the left - right direction with respect to the nut holding portion 80 is restricted. On the other hand, in the nut 210, the inner edges in the left - right direction are in proximity to or in contact with the connecting wall 87 from the outside in the left - right direction. Note that the nut 210 may be a hexagonal nut or the like.

[0072] The bolt 140 is inserted downward into the bolt insertion port 200 through the mounting hole 36. The shaft portion of the bolt 140 is screwed to the nut 210 within the nut accommodation space 83. Thereby, the seat 3 is fixed to the support structure 4.

[0073] Thus, even when a plate nut is used as the nut 210 as in this embodiment, the same operational effects as those of the above-described first embodiment can be achieved. Moreover, in this embodiment, the restricting portion 205 is configured to be continuous with the inner peripheral surface of the outer projecting portion 203. According to this configuration, the restricting portion 205 can be formed in a portion defined by the core pin for forming the outer projecting portion 203 and the core pin for forming the nut accommodation space 83. Thereby, the core pin for forming the outer projecting portion 203 does not cross over the locking surface 206. Thereby, while maintaining the mold release property, the amount of protrusion of the restricting portion 205 from the bottom wall portion 88 can be ensured. Therefore, while suppressing a decrease in manufacturing efficiency due to the addition of the restricting portion 205, it becomes easier to restrict the movement of the nut 210 by the restricting portion 205.

[0074] In the above-described embodiment, the configuration in which the restricting portion 205 is formed along the inner peripheral surface of the outer projecting portion 203 continuous with the bolt insertion port 200 (the configuration in which the bolt insertion port and the through hole are integrated) has been described, but the present invention is not limited to this configuration. For example, a through hole may be formed separately from the bolt insertion port 200, and a restricting portion may be formed along the inner peripheral surface of this through hole.

[0075] (Other Modification Examples) As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the appended claims. In the above-described embodiment, the nude shelter type backrest 2 and seat 3 have been described as an example, but the present invention is not limited to this configuration. The backrest 2 and the seat 3 may be configured to have a cushioning material, or may be configured with a mesh or the like stretched thereover. In the above-described embodiment, the support structure 4 is described as being formed in a frame shape by a pipe or the like, but the structure is not limited to this. The support structure 4 may be configured such that, for example, four leg columns support respective corner portions of the seat 3, or may be configured such that a seat support portion projects from the upper end portion of one leg column. In the above-described embodiment, the structure in which adjacent nut holding portions are connected by ribs is described, but the structure is not limited to this. That is, the nut holding portions may be formed independently.

[0076] In the above-described embodiment, as the connecting portion 70 according to one aspect of the present invention, the structure in which the nut insertion opening 90 opens in the left-right direction and the connecting rib 100 extends in the front-rear direction is described, but the structure is not limited to this. For example, the nut insertion opening may open in the front-rear direction and the connecting rib may extend in the left-right direction. Further, the nut accommodation space 83 may open on both sides in the left-right direction. In the above-described embodiment, the structure in which the connecting rib 100 has two connecting portions 110 and 111 is described, but the structure is not limited to this. The connecting rib 100 may be one or a plurality of three or more. In the above-described embodiment, the case where the positioning recess 89, the bulging portion 35, etc. are used for positioning between the seat 3 and the support structure 4 is described, but the structure is not limited to this. For example, a bulging portion may be formed on the seat 3 and a positioning recess may be formed on the support structure 4.

[0077] In the above-described embodiment, the structure in which the restricting portion is formed in a triangular shape is described, but the structure is not limited to this. The restricting portion may be formed, for example, in a leaf spring shape that extends cantilevered from the inner peripheral edge of the communication port 92. In the above-described embodiment, the structure in which the restricting portion is continuous with the inner surface of the hole formed in the nut holding portion is described, but the structure is not limited to this. The restricting portion may be formed at a portion located closer to the nut insertion opening than the bolt insertion opening. In the above-described embodiment, the configuration in which the bolt insertion port opens the nut accommodation space 83 downward (on one side) has been described, but the configuration is not limited thereto. That is, the bolt insertion port may be configured to open the nut accommodation space 83 upward (on one side) (that is, the bolt insertion port opens on the seating surface 53).

[0078] In addition, within the scope not departing from the gist of the present invention, 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 also be appropriately combined.

Explanation of Reference Numerals

[0079] 1... Chair 3... Seat 4... Support structure 51... Seat body (support plate) 53... Seating surface (load support surface) 80... Nut holding portion 82... Nut 90... Nut insertion port 91... Bolt insertion port 92... Communication port 94... Regulation portion 96... Locking surface 97... Overcoming surface 120... Nut holding portion 140... Bolt 200... Bolt insertion port 203... Outer protruding portion (through hole) 205... Regulation portion 206... Locking surface 207... Overcoming surface 210... Nut

Claims

1. A support plate having a load support surface facing upward, a nut holding portion having a bottom wall facing the lower surface of the support plate in the vertical direction and defining a nut accommodation space for accommodating a nut between the lower surface of the support plate, wherein a nut insertion opening for opening the nut accommodation space in a first direction among the surface directions intersecting in the vertical direction and inserting the nut is formed in the nut holding portion, a bolt insertion opening for opening the nut accommodation space downward and inserting a shaft portion of a bolt through a support structure is formed in the bottom wall, in a portion of the bottom wall that is closer to the nut insertion opening than the bolt insertion opening in the first direction, when the nut is accommodated in the nut accommodation space, it has a locking surface that is locked to the nut in the first direction, and a restricting portion for restricting the movement of the nut in the first direction with respect to the nut holding portion is formed, a communication port is formed in the nut holding portion to open the nut accommodation space downward and communicate the space between the bolt insertion opening and the nut insertion opening in the first direction, the restricting portion is a seat that bulges inside the communication port in a second direction intersecting the first direction among the surface directions with the locking surface facing the bolt insertion opening in the first direction.

2. the nut holding portions are arranged at intervals in a second direction intersecting the first direction among the surface directions, The seat according to claim 1, further comprising a rib that protrudes downward from the support plate and connects the nut holding portions adjacent to each other in the second direction.

3. the restricting portion is configured to be elastically deformable, The seat according to claim 1 or claim 2, wherein an overriding surface that the nut can override is formed on a surface of the restricting portion facing the nut insertion opening in the first direction.

4. The seat according to any one of claims 1 to 3, a chair comprising a support structure connected to the seat, wherein the bolt inserted through the bolt insertion opening is screwed to the nut accommodated in the nut accommodation space.

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