JP2020069349A - Load support member, backrest and chair - Google Patents

Abstract

To provide a load support member which can increase the comfort of a seated person by suppressing reduction in the followability to the elastic deformation in a support part, and provide a backrest and a chair having the same.SOLUTION: A load support member provided in a backrest of a chair includes: a pad body which has a load support surface elastically deforming backward by receiving the load from a seated person and an extension piece extending backward from at least one of an upper end part and a lower end part of the load support surface; and a support body which has a rotation support part rotationally supporting the extension piece around a rotational axis extending along the horizontal direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a load supporting member, a backrest and a chair.

  Conventionally, as a backrest of a chair, one having a lumbar support that supports the lumbar portion of a seated person is known. Patent Document 1 discloses a lumbar support (load supporting member) having a pad material that is curved forward in a convex shape. This pad material is elastically deformed by receiving a load from the front, the central portion in the vertical direction is recessed rearward, and the upper portion and the lower portion are flexed outward in the vertical direction.

JP, 2006-280416, A

  In the lumbar support of Patent Document 1, the upper edge portion and the lower edge portion of the pad material are fixedly supported by the base member. Therefore, when a load is applied to the pad material and the pad material elastically deforms, the bending of the upper portion and the lower portion of the pad body is hindered in the vicinity of the support portion. As a result, the elastic deformation of the pad material may be insufficient and the comfort of the seated person may be impaired.

  The present invention has been made in view of such a problem, and includes a load support member capable of suppressing deterioration in followability to elastic deformation of a support portion and enhancing comfort of a seated person, and the load support member. The purpose is to provide a backrest and a chair.

  A load supporting member according to one aspect of the present invention is a load supporting member provided on a backrest of a chair, and a load supporting surface that is elastically deformed rearward when receiving a load from a seated person and an upper end portion of the load supporting surface. A pad body having an extending piece extending rearward from at least one of the lower end portions, and a support body having a rotation support portion that rotatably supports the extending piece around a rotation axis extending in the horizontal direction are provided.

  According to the above configuration, the pad body is rotatably supported by the extension piece. For this reason, when the pad body is elastically deformed by receiving a stress from the seated person on the load supporting surface, the rear end portion of the extending piece rotates in the vertical direction. That is, elastic deformation of the pad body is not hindered in the vicinity of the support portion. As a result, the rearward elastic deformation of the pad body is promoted, the seated person can be supported by a wider surface, and the comfortability of the seated person can be enhanced.

  In the load supporting member described above, one of the extension piece and the rotation support portion has a pivot portion around the rotation axis, and the other of the extension piece and the rotation support portion is the pivot axis. It may be configured to have a bearing portion that rotatably supports the portion.

  According to the above configuration, the extension piece is supported by the rotation support portion by inserting the pivot portion into the bearing portion. Therefore, with a simple structure, the rotation support mechanism can be configured by the rotation support portion of the extending piece.

  In the load supporting member described above, the extending piece has an arc-shaped rear end surface having the rotation axis as a center, and the rotation supporting portion opposes the rear end surface in the front-rear direction with a gap therebetween to rotate the rotation. It may be configured to have arcuate facing surfaces centered on the axis.

  According to the above configuration, the rear end surface of the extending piece and the facing surface of the rotation supporting portion, which are opposed to each other in the front-rear direction, are both arcuate about the rotation axis. Therefore, even if the extending piece rotates about the rotation axis, the size of the gap between the rear end surface and the facing surface does not change. Therefore, it is possible to prevent the external member from being caught in the gap between the rear end surface and the facing surface due to the rotation of the extending piece. Further, by sufficiently narrowing the gap between the rear end surface and the facing surface, it is possible to prevent dust and the like from entering the rotating mechanism. In the above configuration, one of the rear end surface and the facing surface is a concave arc surface centering on the rotation axis, and the other is a convex arc surface centering on the rotation axis.

  In the load supporting member described above, the load supporting surface has a convex surface shape that projects forward, the forward projecting apex of the load supporting surface is arranged biased to one side in the vertical direction, the pad body, At least the extension piece extending rearward from one end of the load support surface on the one side in the vertical direction may be rotatably supported by the rotation support portion.

  According to the above configuration, the projecting vertices of the load supporting surface are arranged so as to be biased to one side in the vertical direction. For example, when the load supporting member is a lumbar support, the projecting apex of the load supporting surface is arranged so as to be biased to the upper side in order to support the lumbar portion of the seated person from obliquely below. In this case, in the load support surface, the distance dimension of the upper region of the projecting apex is smaller than the distance dimension of the lower region of the projecting apex. Therefore, when a load is applied to the load supporting surface, the displacement of the upper region toward the upper side becomes larger than the displacement of the lower region toward the lower side. According to the above configuration, by rotationally supporting the extending piece extending rearward from the end on the side where the projecting apexes of the load supporting surface are biased, it is possible to suppress the inhibition of the deformation of the pad body in the supporting portion and to sit. The comfort of the person can be improved.

  In the load supporting member described above, the pad body has a pair of the extending pieces extending rearward from an upper end portion and a lower end portion of the load supporting surface, and the supporting body includes a pair of the extending pieces, respectively. It may be configured to have a pair of the rotation support portions that are rotatably supported.

  According to the above configuration, the pad body is rotatably supported by the support body at the extended pieces at the upper end and the lower end. Therefore, regardless of whether the pad body is elastically deformed to the upper side or the lower side, the elastic deformation is not obstructed at the upper end and the lower end. As a result, the rearward elastic deformation of the pad body is promoted, and the seated person can be supported by a wider surface.

  In the load supporting member described above, the load supporting surface and the extending piece may be continuous so as to form a gentle curved shape.

  According to the above configuration, since the extending piece is smoothly connected to the load supporting surface at the upper end portion or the lower end portion of the load supporting surface, the extension piece can be formed as a whole as compared with the case where the extending piece extends rearward in a straight line. Deformation is hard to be hindered.

  In the above load supporting member, the load supporting member may be a lumbar support.

  According to the above configuration, the load supporting member can support the lumbar portion of the occupant as a lumbar support and enhance the comfort of the occupant.

  A backrest of one aspect of the present invention includes a backrest main body that supports the back of a seated person, and the above-described load support member attached to the backrest main body.

  According to the above configuration, it is possible to provide a backrest that can improve the comfort of the seated person.

  A chair of one embodiment of the present invention includes the backrest described above.

  According to the above-mentioned composition, the chair which can raise the comfort of the seated person can be provided.

  According to the present invention, it is possible to provide a load support member capable of suppressing deterioration in the ability of a support portion to follow elastic deformation and enhancing comfort of a seated person, and a backrest and a chair including the load support member.

FIG. 1 is a front view of a chair according to an embodiment. FIG. 2 is a rear view of the chair according to the embodiment. FIG. 3 is a side view of the backrest of the embodiment. FIG. 4 is an exploded view of the lumbar support of one embodiment. FIG. 5 is a cross-sectional view of the lumbar support of one embodiment.

Hereinafter, with reference to an accompanying drawing, a form for carrying out a backrest and a chair provided with it in the present invention is explained. However, the present invention is not limited to this embodiment.
In each of the following drawings, in order to make each component easy to see, the scale of dimensions may be different depending on the component.

  In the following description, the direction facing the front of a person who is seated in a regular posture with his back facing the back of the chair is called "front", and the direction opposite to that is called "rear". In addition, the upward direction of a person who sits in a normal position on a chair is called "up", and the opposite direction is called "down". Is called "right". Also, the left-right direction of the chair is called the "width direction".

  Further, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the "X direction" is a direction parallel to the "width direction" of the chair shown in FIG. The “Z direction” is the direction orthogonal to the X direction and is the “vertical direction” in FIG. The “Y direction” is the “front-back direction” that is orthogonal to both the X direction and the Z direction.

(Chair)
FIG. 1 is a front view showing a configuration of a chair 1 according to one aspect of the present embodiment. FIG. 2 is a rear view showing the configuration of the chair 1 according to one aspect of the present embodiment.

  As shown in FIG. 1, a chair 1 according to the present embodiment has a leg portion 2 placed on a floor surface, a box-shaped support base 3 installed at an upper end of the leg portion 2, and a seated person sits down. A seat body 4, a seat receiving member 5 mounted on the upper surface of the support base 3 and supporting the seat body 4, and a back supporting the back of a seated person who extends from the support base 3 to the upper rear side and seats on the seat body 4. The lean 6 is provided.

  The leg portion 2 includes a multi-legged leg 7 with casters 7a, and a pedestal 8 standing upright from the central portion of the multi-legged leg 7 and having a gas spring as an elevating mechanism built therein.

  The support base 3 is attached to the upper end of the pedestal 8. The support base 3 has a built-in lift adjusting mechanism for the pedestal 8 and a tilt adjusting mechanism for the backrest 6.

  The seat body 4 includes a seat body outer peripheral frame body portion 13 forming a skeleton portion, and a seat body face material 14 stretched on the seat body outer peripheral frame body portion 13.

  The seat outer peripheral frame main body 13 is formed of, for example, a synthetic resin, and has a substantially rectangular shape with rounded four corners in a top view. A groove 13m that is recessed toward the inside of the seat outer peripheral frame body 13 is continuously formed in the outer peripheral edge portion of the seat outer peripheral frame body 13 in the circumferential direction.

  The seat body surface member 14 is in the form of a mesh in which a large number of holes are formed, and the outer peripheral end thereof is wound into the groove 13m formed in the seat body outer peripheral frame body portion 13 and inserted into the groove 13m. It is fixed to the seat outer peripheral frame body portion 13 by the edge material.

  The backrest 6 supports the load from the back of the occupant seated on the seat body 4. A part of the backrest 6 is connected to the tilt adjusting mechanism in the support base 3.

(Back)
Hereinafter, a specific configuration of the backrest 6 in this embodiment will be described.
As shown in FIG. 2, the backrest 6 includes a backrest main body 20 that supports the back of a seated person, and a lumbar support (load support member) 30 attached to the backrest main body.

  The backrest body 20 includes an outer peripheral frame member 28, a backrest face member 29 stretched over the outer peripheral frame member 28, and a backrest support member 22 that supports the outer peripheral frame member 28. A decorative plate 23 that covers the fastening portion of the backrest support member 22 is attached to the rear of the backrest support member 22.

  The outer peripheral frame member 28 has a rectangular frame shape. The outer peripheral frame member 28 has a pair of vertical rods 28a, an upper rod 28b, and a lower rod 28c, which are separated in the width direction (X direction). The upper rod 28b connects the upper ends of the pair of vertical rods 28a. The lower rod 28c connects the lower ends of the pair of vertical rods 28a. The outer peripheral frame member 28 is fixed to the backrest support member 22. The outer peripheral frame member 28 is made of, for example, resin or aluminum alloy.

  The backrest face material 29 is a mesh-like cloth in which a large number of holes are formed. The backrest face material 29 is fixed to the outer peripheral frame member 28 by being wound into a groove (not shown) provided in the outer peripheral frame member 28 at the outer peripheral end portion. The back of the seated person sitting on the seat body 4 contacts the front surface of the backrest face material 29. By stretching the cloth-like backrest surface member 29 on the outer peripheral frame member 28, the back of the seated person can be supported with appropriate elasticity.

  The backrest support member 22 is arranged behind the outer peripheral frame member 28. The backrest support member 22 supports the outer peripheral frame member 28. The backrest support member 22 supports the seat body 4. Although a detailed description of the means for attaching the backrest support member 22, the outer peripheral frame member 28, and the seat body 4 is omitted, for example, a plurality of fasteners are used.

  FIG. 3 is a side view showing the configuration of the backrest 6 according to one aspect of the present embodiment. Note that, in FIG. 3, the backrest face material 29 and the decorative plate 23 are not shown. Further, in FIG. 3, the backrest body 20 is shown in cross section in the center in the width direction for easy viewing.

  The backrest support member 22 has a pair of side rod portions 22A, a first horizontal rod portion 22B, a second horizontal rod portion 22C, and a pair of extending portions 22D.

  The pair of side rods 22A extends in the vertical direction along the pair of vertical rods 28a of the outer peripheral frame member 28, respectively. The backrest support member 22 supports the outer peripheral frame member 28 at the pair of side rod portions 22A.

  The first horizontal rod portion 22B extends along the left-right direction and connects the upper end portions of the pair of side rod portions 22A. As will be described later, the lumbar support 30 is attached to the first horizontal rod portion 22B.

  The extending portion 22D extends forward from the lower end of the first horizontal rod portion 22B. The backrest support member 22 is attached to the support base 3 at the pair of extending portions 22D.

  The second horizontal rod portion 22C is located below the first horizontal rod portion 22B. The second horizontal rod portion 22C extends in the left-right direction from the boundary portion between the side rod portion 22A and the extension portion 22D. The second horizontal rod portion 22C connects the pair of side rod portions 22A to each other. The second horizontal rod portion 22C connects the pair of extending portions 22D to each other.

(Lumber support (load support member))
As shown in FIG. 3, the lumbar support 30 is provided on the backrest 6 of the chair 1. The lumbar support 30 is arranged at a position corresponding to the lumbar region of a seated person who is seated on the chair 1. The lumbar support 30 receives the load of the seated person who goes from the front side to the rear side from the rear surface side of the backrest face material 29.

  The lumbar support 30 includes a base body 31 supported by the first horizontal rod portion 22B of the backrest support member 22, a support body 33 supported by the base body 31, and a pad body 37 supported by the support body 33. ..

  The base 31 has a pair of fixing portions 31a fixed to the first horizontal rod portion 22B, and a holding portion 32 that supports the support body 33.

  The pair of fixing portions 31 a are located behind the grip portion 32. The pair of fixing portions 31a are arranged along the width direction. Through holes are provided in the pair of fixing portions 31a so as to penetrate in the vertical direction. A fixing screw for fixing the fixing portion 31a to the first horizontal rod portion 22B is passed through the through hole of the fixing portion 31a. The fixing portion 31a is fixed to the first horizontal rod portion 22B by a fastening screw and a nut screwed with the fastening screw while being inserted into the hole portion 22Ba provided in the first horizontal rod portion 22B.

  FIG. 4 is an exploded view of the lumbar support 30. In FIG. 4, for ease of viewing, the backrest body 20 is shown in cross section in the center in the width direction.

  The grip portion 32 includes a base portion 32a located behind the support body 33, a pair of side portions 32b extending forward from the base portion 32a, and a pair of sandwiching portions 32c extending inward in the width direction from front end portions of the pair of side portions 32b. And have. In addition, engaging projections 32ca protruding inward in the width direction are provided on end surfaces on the inner side in the width direction of the pair of sandwiching portions 32c. The grip portion 32 is configured by the base portion 32a, the pair of side portions 32b, and the pair of holding portions 32c to have a C-shape that is open to the front when viewed in the vertical direction. That is, the grip portion 32 has a C-shaped plan view. The grip part 32 grips the support body 33 in an internal space having a C-shape in a plan view.

  The support body 33 has a slide plate 34 extending in the up-down direction, and a pair of rotation support portions 35 located at the upper end and the lower end of the slide plate 34, respectively.

  The slide plate 34 is fitted in a space surrounded by the base portion 32a of the grip portion 32, the pair of side portions 32b, and the pair of holding portions 32c. As a result, the slide plate 34 is gripped by the grip portion 32. The slide plate 34 is vertically movable within a space surrounded by the base portion 32a of the grip portion 32, the pair of side portions 32b, and the pair of holding portions 32c.

  A pair of corrugated ribs 34 a is provided on the front surface of the slide plate 34. The wavy rib 34 a projects forward from the front surface of the slide plate 34. The wavy rib 34a extends in the vertical direction while meandering in the width direction. The pair of corrugated ribs 34a respectively faces the sandwiching portion 32c in the width direction. A plurality of engagement notches 34b arranged in the vertical direction are formed on the surfaces of the pair of wavy ribs 34a facing outward in the width direction. The engagement notch 34b is a recess that is recessed inward in the width direction. An engagement protrusion 32ca provided on the holding portion 32c engages with any one of the plurality of engagement notches 34b.

  According to this embodiment, the engagement protrusion 32ca of the grip portion 32 engages with any one of the plurality of engagement notches 34b arranged in the vertical direction. Therefore, the support 33 is fixed to the base 31 at any of a plurality of stages. Further, by changing the engagement notch 34b that engages with the engagement protrusion 32ca, it is possible to adjust the vertical position of the support 33 with respect to the base 31. That is, according to the present embodiment, the vertical position adjustment of the pad body 37 with respect to the backrest body 20 becomes possible.

  The pair of rotation support portions 35 are arranged in the vertical direction. The rotation support portion 35 has a facing surface 35a facing forward, a pair of protruding pieces 35b protruding forward from the facing surface 35a, and a pair of pivot portions 36 respectively provided on the pair of protruding pieces 35b. The pivot portion 36 has a columnar shape centered on the rotation axis J. Here, the rotation axis J is an imaginary axis line extending along the width direction.

  In the present embodiment, the pair of rotation support portions 35 located at the upper end portion and the lower end portion of the slide plate 34 have substantially the same shape. However, the pair of rotation support portions 35 do not necessarily have to have the same shape.

  The facing surface 35a has a concave shape that is recessed rearward. The facing surface 35a is an arc-shaped surface centered on the rotation axis J when viewed in the width direction. The facing surface 35a faces the rear end surface (the rear end surface 38c described later) of the pad body 37 in the front-rear direction with a gap.

  The pair of projecting pieces 35b are plate-shaped with the width direction being the plate thickness direction. The pair of protruding pieces 35b are arranged in the width direction.

  The pivot portion 36 projects outward in the width direction from a surface of the projecting piece 35b facing outward in the width direction. The pair of pivot portions 36 provided on one rotation support portion 35 are arranged on a single rotation axis J.

FIG. 5 is a sectional view of the lumbar support 30.
The pad body 37 has a pad body portion 38 that directly receives the load of the seated person via the backrest face material 29.

  The pad body 38 is made of an elastically deformable soft material such as elastomer. The pad main body 38 has a load supporting surface 38a facing forward and a pair of extending pieces 38b extending rearward from the upper end and the lower end of the load supporting surface 38a. That is, the pad body 37 has the load supporting surface 38a and the pair of extending pieces 38b.

The load support surface 38a has a substantially uniform shape and extends in the left-right direction. The load support surface 38a has a convex shape protruding forward. The forward projecting apex P of the load supporting surface 38a is arranged biased to the upper side. Accordingly, the load support surface 38a can support the lumbar portion of the seated person from obliquely below.
In addition, depending on the mounting posture of the lumbar support 30, the projecting apex P of the load supporting surface 38a may be arranged so as to be biased downward. That is, the projecting vertices P of the load supporting surface 38a may be arranged so as to be biased to one side in the vertical direction.

  The load supporting surface 38a receives a load F from a seated person from diagonally above. As shown by the chain double-dashed line in FIG. 5, the load support surface 38a receives the load F and elastically deforms rearward. Along with this, the upper end of the load supporting surface 38a bends upward, and the lower end of the load supporting surface 38a bends downward.

  The pair of extending pieces 38b are arranged vertically. The upper extending piece 38 b is supported by the upper rotary support portion 35 of the support body 33. Further, the lower extended piece 38 b is supported by the lower rotary support portion 35 of the support body 33. The pair of extending pieces 38b are connected to the load supporting surface 38a in a gently curved shape at the upper end portion and the lower end portion of the load supporting surface 38a. That is, the load supporting surface 38a and the extending piece 38b are continuous so as to form a gentle curved shape. In the pad body 37 of the present embodiment, the deformation of the entire pad body 37 is less likely to be hindered, as compared with the case where the extending piece linearly extends rearward. As shown by the chain double-dashed line in FIG. 5, the upper extending piece 38b tilts upward as the load supporting surface 38a deforms, and the lower extending piece 38b tilts downward as the load supporting surface 38a deforms. ..

  A bearing member 39 is embedded in each of the pair of extending pieces 38b. The pair of bearing members 39 are arranged side by side along the vertical direction. The bearing member 39 is made of a hard material such as a resin material or a metal material. The bearing member 39 is embedded by insert molding inside the extending piece 38b of the pad main body 38, for example. In the present specification, the bearing member 39 is a part of the extending piece 38b.

  The bearing member 39 has a concave shape that opens rearward. Inside the bearing member 39, a housing space 39A that opens rearward is provided. The protruding piece 35b of the rotation support portion 35 is inserted into the accommodation space 39A from the rear side.

  Bearing portions 39a are provided on a pair of inner wall surfaces of the bearing member 39 that face inward in the width direction. That is, the extending piece 38b has the bearing portion 39a. The bearing portion 39a is a recessed portion that is recessed outward in the width direction from the inner wall surface of the bearing member 39 that faces the inside in the width direction. The bearing portion 39a has a circular shape centered on the rotation axis J in a plan view. The pivot portion 36 of the rotation support portion 35 is inserted into the bearing portion 39a. The bearing portion 39a supports the pivot portion 36 rotatably around the rotation axis J.

  According to this embodiment, the rotation support portion 35 rotates and supports the extending piece 38b around the rotation axis J extending in the horizontal direction. Therefore, when the load support surface 38a receives a stress from a seated person and the pad body 37 elastically deforms, the rear end portion of the extending piece 38b rotates in the vertical direction. More specifically, when the pad body 37 is elastically deformed, the upper extension piece 38b rotates upward about the rotation axis J, and the lower extension piece 38b rotates downward about the rotation axis J. Therefore, the pad body 37 is not hindered from being elastically deformed in the vicinity of the support portion. As a result, rearward elastic deformation of the pad body 37 is promoted, the seated person can be supported by a wider surface, and the comfort of the seated person can be enhanced.

  In the present embodiment, the pad body 37 has a pair of extending pieces 38b extending rearward from the upper end portion and the lower end portion of the load supporting surface 38a. Further, the support body 33 has a pair of rotation support portions 35 that respectively rotate and support the pair of extension pieces 38b. That is, the pad body 37 is rotatably supported by the support body 33 at the extended pieces 38b at the upper end and the lower end, respectively. Therefore, even when the pad body 37 is elastically deformed to either the upper side or the lower side, the elastic deformation is not hindered by the support portions at the upper end and the lower end. As a result, rearward elastic deformation of the pad body 37 is promoted, and the seated person can be supported by a wider surface.

  In the present embodiment, the case where the pair of extending pieces 38b of the pad body 37 are rotatably supported has been described. However, the pad body 37 may have only one extending piece 38b. Further, the pad body 37 may be rotatably supported by only one of the pair of extending pieces 38b. In this case, the other extended piece may or may not be fixedly supported. That is, the pad body 37 may have at least one extending piece 38b that extends rearward from at least one of the upper end portion and the lower end portion of the load supporting surface 38a and is rotatably supported by the rotation supporting portion 35.

Further, it is preferable that at least the pad body 37 is rotatably supported by the extending piece 38b on the side (in the present embodiment, the upper side) on which the projecting apex P of the load supporting surface 38a is arranged deviated. In the load supporting surface 38a, a region above the projecting vertex P is an upper region 38aa, and a region below the projecting vertex P is a lower region 38ab. The projecting apex P of the load supporting surface 38a of the present embodiment is arranged so as to be biased upward. Therefore, the vertical distance dimension of the upper region 38aa is smaller than the vertical distance dimension of the lower region 38ab. When a load is applied to the load supporting surface 38a, the upper displacement of the upper region 38aa becomes larger than the lower displacement of the lower region 38ab. Therefore, at least by rotationally supporting the upper extended piece 38b supporting the upper region 38aa, it is possible to suppress the inhibition of the deformation of the pad body 37 and enhance the comfort of the seated person.
In the present embodiment, the projecting apex P of the load supporting surface 38a is arranged so as to be biased upward. However, the projecting apex P may be biased downward. In this case, at least the lower extension piece 38b may be rotatably supported.

  In the present embodiment, the case where the rotation support portion 35 has the pivot portion 36 and the extending piece 38b has the bearing portion 39a has been described. However, the rotation support portion 35 may have a bearing portion and the extending piece 38b may have a pivot portion. That is, it suffices that one of the extending piece 38b and the rotation support portion 35 has the pivot portion 36, and the other has the bearing portion 39a. By employing the mechanism having the concave bearing portion 39a and the pivot portion 36 inserted into the bearing portion 39a, the extending piece 38b can be rotated with respect to the rotation supporting portion 35 with a simple structure.

  As shown in FIG. 5, the extending piece 38b has a rear end surface 38c facing rearward. The rear end surface 38c has a convex shape protruding rearward. The rear end surface 38c is an arcuate surface centered on the rotation axis J when viewed in the width direction. The rear end surface 38c faces the facing surface 35a of the rotation support portion 35 in the front-rear direction with a gap.

  According to the present embodiment, the rear end surface 38c of the extending piece 38b and the facing surface 35a of the rotation support portion 35, which are opposed to each other in the front-rear direction, are both arc-shaped with the rotation axis J as the center. Therefore, even if the extending piece 38b rotates about the rotation axis J, the size of the gap between the rear end surface 38c and the facing surface 35a does not change. Therefore, it is possible to prevent the external member from being caught in the gap between the rear end surface 38c and the facing surface 35a due to the rotation of the extending piece 38b. Further, by sufficiently narrowing the gap between the rear end surface 38c and the facing surface 35a, it is possible to prevent dust and the like from entering the rotating mechanism.

  In addition, in this embodiment, the case where the rear end surface 38c is a convex arc surface and the facing surface 35a is a concave arc surface has been described. However, the rear end surface 38c may be a concave arc surface and the facing surface 35a may be a convex arc surface.

  Although the embodiment of the present invention has been described above, each configuration and combination thereof in the embodiment are examples, and addition, omission, replacement, and other changes of the configuration are included without departing from the spirit of the present invention. Is possible. The present invention is not limited to the embodiments.

  In the embodiment described above, the configuration in which the lumbar support 30 as the load supporting member is provided on the backrest 6 has been described. However, the above configuration may be adopted in other load supporting members such as a headrest.

  Further, in the above-described embodiment, the case where the projecting apex P of the load supporting surface 38a is biased to one side in the vertical direction (more specifically, to the upper side) has been described. However, the load supporting surface 38a may have a vertically symmetrical shape. In this case, the projecting apex P of the load supporting surface 38a is located at the vertical center of the load supporting surface 38a.

DESCRIPTION OF SYMBOLS 1 ... Chair, 6 ... Backrest, 20 ... Backrest main body, 30 ... Lumber support (load support member), 33 ... Support body, 35 ... Rotation support part, 35a ... Opposing surface, 36 ... Axis part, 37 ... Pad body , 38a ... Load supporting surface, 38b ... Extension piece, 38c ... Rear end surface, 39a ... Bearing part, F ... Load, J ... Rotating shaft, P ... Projection apex

Claims (9)

A load supporting member provided on a back of a chair,
A pad body having a load supporting surface that is elastically deformed rearward when receiving a load from a seated person and an extending piece that extends rearward from at least one of an upper end portion and a lower end portion of the load supporting surface,
A support having a rotation support portion that rotatably supports the extension piece about a rotation axis extending along the horizontal direction.
Load support member. One of the extending piece and the rotation support portion has a pivot portion around the rotation axis,
The other of the extending piece and the rotation supporting portion has a bearing portion that rotatably supports the pivot portion,
The load supporting member according to claim 1. The extending piece has an arc-shaped rear end surface having the rotation axis as a center,
The rotation support portion has an arcuate facing surface that faces the rear end surface in the front-rear direction through a gap and has the arc of rotation as a center.
The load supporting member according to claim 1. The load support surface has a convex shape protruding forward,
The forward projecting apex of the load supporting surface is arranged biased to one side in the vertical direction,
The pad body is rotatably supported by the rotation support portion, at least in the extension piece extending rearward from an end portion on one side in the vertical direction of the load support surface.
The load supporting member according to claim 1. The pad body has a pair of the extending pieces extending rearward from the upper end portion and the lower end portion of the load supporting surface,
The support has a pair of rotation support portions that respectively rotate and support the pair of extension pieces,
The load supporting member according to any one of claims 1 to 4. The load bearing surface and the extending piece are continuous so as to form a gentle curved line,
The load supporting member according to any one of claims 1 to 5. The load support member is a lumbar support,
The load supporting member according to any one of claims 1 to 6. A backrest body that supports the back of a seated person,
The load supporting member according to any one of claims 1 to 7, which is attached to the backrest body.
Backrest.   A chair comprising the backrest according to claim 8.

Images