JP6665496B2 - Chair - Google Patents

Description

  The present invention relates to a chair suitably used in an office or the like.

  2. Description of the Related Art Conventionally, a chair in which a lumbar support is attached to a backrest is known (for example, see Patent Literature 1). Many of the lumbar supports are provided between the side frame portions constituting the backrest, and generally have a horizontally long rectangular shape when viewed from the front.

  In such a case, the upper portion of the lumbar support may not be able to appropriately follow the load of the occupant in some cases.

JP 2013-094287 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a chair having a lumbar support in which an upper region is appropriately bent.

  That is, the present invention has the following configuration.

The invention according to claim 1 is a chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest, wherein the side frame portions are gradually deviated inward downward. to are those having the formed lower frame portion of the right and left, the lumbar support includes a lumbar support body which forms a plate, the lower frame portion component of the right and left is provided at both ends of the lumbar support body The lumbar support body integrally includes a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region. The upper region extends upward from the entire upper edge of the band-shaped region, and the width dimension in the left and right direction gradually decreases upward. A chair that.

The invention according to claim 2 is a chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest, wherein the side frame portions are gradually displaced inward downward. are those having a lower frame portion of the left and right that are formed as the lumbar support, and lumbar support body which forms a plate, the lower frame portion component of the right and left is provided at both ends of the lumbar support body The lumbar support main body has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region. to are those formed by having the mounting portion, and a shape along the longitudinal direction of the lower frame portion component of the right and left, are the chair is made extends below the strip region

The invention according to claim 3 is a chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest, wherein the side frame portions are gradually displaced inward downward. are those having a lower frame portion of the left and right that are formed as the lumbar support, and lumbar support body which forms a plate, the lower frame portion component of the right and left is provided at both ends of the lumbar support body The lumbar support main body has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region. Wherein the lumbar support body includes a lower region extending downward from a lower edge of the band-shaped region, and the lower region is provided at a lower edge of the band-shaped region. A chair in which provided between the end portion near and said attachment portion that.

The invention according to claim 4 is a chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest, wherein the side frame portions are gradually deviated inward downward. are those having a lower frame portion of the left and right that are formed as the lumbar support, and lumbar support body which forms a plate, the lower frame portion component of the right and left is provided at both ends of the lumbar support body The lumbar support main body has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region. The chair has a convex shape in a front view.

The invention according to claim 5 is the chair according to claim 1, 2 , 3, or 4 , wherein the upper region has a shape in which an upper edge portion is warped rearward.

  As described above, according to the present invention, it is possible to provide a chair having a lumbar support in which the upper region flexes favorably with respect to the belt-shaped region.

FIG. 1 is a perspective view showing an embodiment of the present invention. The front view in the embodiment. The rear view in the embodiment. The right view in the embodiment. The left view in the embodiment. The top view in the embodiment. The bottom view in the embodiment. The partial enlarged left view in the embodiment. FIG. 3 is a partially enlarged left side view illustrating the positioning mechanism of the embodiment. FIG. 3 is a partially enlarged left side view illustrating the positioning mechanism of the embodiment. The exploded perspective view in the embodiment. The exploded perspective view in the embodiment. The exploded perspective view in the embodiment. The exploded perspective view in the embodiment. The front view in the embodiment. The exploded perspective view in the embodiment. FIG. 4 is a partially enlarged rear view of a front frame in the same embodiment. XX sectional drawing in FIG. The exploded perspective view in the embodiment. The exploded perspective view in the embodiment. FIG. 5 is a sectional view taken along line U-U in FIG. 4. The exploded perspective view in the embodiment. The front view which shows the lumbar support of the embodiment. The rear view which shows the lumbar support of the embodiment. The right view which shows the lumbar support of the embodiment. FIG. 16 is a sectional view taken along line YY in FIG. 15. FIG. 16 is a sectional view taken along line ZZ in FIG. 15. The perspective view in the embodiment. The perspective view in the embodiment. The exploded perspective view in the embodiment. The top view in the embodiment. The top view in the embodiment. The top view in the embodiment. FIG. 5 is a sectional view taken along line VV in the same embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair A suitably used in an office or the like.

  The chair A includes a leg B, a support base C pivotally supported by the leg B, a seat D arranged on the support base C, and a support that can tilt backward with respect to the support base C. And the armrest P attached to the seat D. The backrest structure F includes a back support G rotatably supported by the support base C, and a backrest H supported by the support base C via the back support G so as to be able to tilt backward. Have been.

  Hereinafter, each configuration of the chair A will be described in detail.

<< Leg B >>
The leg B includes a plurality of radially arranged leg blades b1 each having a caster b3 at a distal end, and a leg support b2 erected at a base end of the leg blades b1. The leg support b2 has a gas spring (not shown) that can expand and contract in the vertical direction, and supports the support base C so that the position of the support base C can be changed vertically.

<<< Support base C >>>
The support base C is mainly configured by a main frame c1 having a frame shape in plan view. The main frame c1 includes left and right side block portions c2, a front block portion c3 connecting between the front ends of the left and right side block portions c2, and a rear block portion c4 connecting between the rear ends of the left and right side block portions c3. It has.

  A main shaft j1 extending in the left-right direction is penetrated in the side block portion c2. The back support G is rotatably supported on the support base C via the main shaft j1.

  The front block portion c3 is provided with bearing portions c5 of the front link shaft j2 arranged in pairs on the left and right. The bearing portion c5 of the front link shaft j2 projects upward.

  The rear block portion c4 includes a cylindrical portion c6 fixed to the leg support b2, and a rear wall c7 provided at a rear portion of the cylindrical portion c6. The rear wall c7 constitutes a receiving member N of the rearward tilt locking mechanism I, which will be described later. The rear wall c7, which is the receiving member N, has a plurality of concave engaging portions c8 that are open rearward. Are provided at intervals in the vertical direction.

<<<< seat D >>
The seat D includes a seat receiver d1 having a shell shape, and a seat body d2 provided on the seat receiver d1 so as to be able to change the front-rear position. The front portion of the seat D is supported via a front link c9. C and a rear portion thereof is supported by the support base C via a rear link g4 of the back support G. The seat support d1 has a front bearing portion d3 on its lower surface for holding a front connecting shaft j3 extending in the left and right direction supported by the upper end of the front link c9, and a left and right direction penetrating the rear link g4. A rear bearing d4 for holding the extended rear connection shaft j4 is provided. Note that an armrest P is attached to the seat support d1.

  The seat D is configured to move in synchronization with the backward tilting operation of the backrest H by the locking mechanism J. The seat support d1 is provided with a rearward locking operation lever d5 for operating the rearward locking mechanism I, and an elevating operation lever d6 for operating the gas spring of the leg B.

<< Back support G >>
The back support G includes left and right arms g1 rotatably supported by a main shaft j1 via a bush g3, and a mounting plate g2 rigidly connecting the rear ends of the arms g1. The back support G is made of metal, and the arm g1 and the mounting plate g2 are joined by welding.

  The left and right arms g1 are a pair of plates that extend in the front-rear direction and have a shaft hole a1 at an intermediate portion in the front-rear direction. The left and right arms g1 are rotatably supported by the main shaft j1 via a bush g3 mounted on the shaft hole a1.

  The bush g3 is formed of a synthetic resin, has a cylindrical shape having a flange portion g5 on the outer periphery of an inner end, and is mounted from the inside to a shaft hole a1 provided in the arm g1. In the mounted state, the flange g5 of the bush g3 is in contact with the inner surface of the arm g1. In addition, a positioning protrusion g6 is provided on the outer surface of the flange portion g5 so as to project therefrom, and the positioning protrusion g6 is fitted into a positioning hole a2 provided in the arm g1.

  In the vicinity of the shaft hole a1 at the upper edges of the left and right arms g1, a rear link g4 extending obliquely forward and upward is integrally formed. A shaft hole g41 is formed at the upper end of the rear link g4, and a rear connecting shaft j4 extending in the left-right direction is penetrated. Both ends of the rear connection shaft j4 are engaged with the rear bearing portion d4 of the seat support d1. A receiving shaft j5 is provided between the front ends of the left and right arms g1. The backrest H is turned forward between the receiving shaft j5 and the front end of the support base C via a back support G. A reaction force mechanism E for urging the movement is provided. Here, reference symbol E is a coil spring constituting the reaction force mechanism E.

  The mounting plate g2 is provided with a plurality of bolt insertion holes h1 for inserting the plurality of bolts v1. A nut (not shown) is provided on the lower surface side of each bolt insertion hole h1. Further, a wire insertion for inserting an operation force transmitting wire w provided between a rearward locking lock operation lever d5 provided on the seat D and a rearward locking mechanism I described later is inserted through the mounting plate g2. A hole e1 is formed.

<< Backrest H >>
The backrest H is provided on the back frame 1, a concealing member 2 provided at the front end of the back frame 1, a front back frame 3 disposed on the front side of the back frame 1, and provided on the front back frame 3. A tension member 4, a lumbar support 5 located on the back side of the tension member 4 and attached to the front back frame 3, and the lumbar support 5 and the front back frame 3 supporting the tension member 4 are attached to the back frame 1. And a positioning mechanism 6 for positioning so that the position can be changed in the front-rear direction.

  The backrest H has a front frame 3 on which a tension member 4 is provided on the front side of the back frame 1 so as to be changeable in the front-rear direction. With such a configuration of the backrest H, the front back frame 3 is easily made to have a structure that is easily elastically deformed as a whole, and the front back frame 3 is provided with flexibility such that the back of the seated person is wrapped. It is easy. The entire backrest H can be tilted rearward around a main shaft j1 provided on the support base C. Specifically, the backrest H is rotatably supported around a main axis j1 of a support base C via a back support G.

<Spine frame 1>
The back frame 1 performs a backward tilting operation around a main shaft j1 provided on the support base C, and is provided between the left and right side frame portions 1a and the upper end portions of the left and right side frame portions 1a. The frame portion 1b, the left and right lower frame portions 1c extending forward from the lower ends of the left and right side frame portions 1a, respectively, and these left and right lower frame portions 1c are joined together and fastened to the mounting plate g2 of the back support G. And a lower connecting portion 1d. The left and right side frame portions 1a, the upper frame portion 1b, the left and right lower frame portions 1d, and the lower connecting portion 1d are integrally formed of synthetic resin.

  The left and right side frame portions 1a of the back frame 1 each have a shape of a member that gradually widens downward. The side frame portion 1a of the back frame 1 is disposed on the back side of the side of the backrest surface mainly composed of the stretching member 4 stretched on the front back frame 3. Each of the left and right side frame portions 1a has a substantially rectangular shape in a side view and a front view, and connects the upper frame portion 11 and the lower frame portion 13 via the bent portion 12. It is made continuous. In the upright state, the upper frame portion 11 is inclined rearward in a side view, and the lower frame portion 13 is inclined forward in a side view.

  The upper frame portion 1b of the back frame 1 is disposed on the upper back side of the backrest surface, and is a structural frame that connects the upper ends of the side frame portions 1a. The upper frame portion 1b is provided with an element constituting an upper connecting portion for attaching the upper end portion of the front back frame 3. That is, a plurality of concave portions 14 opening forward are provided on the front surface of the upper frame portion 1b at intervals in the left-right direction. A bolt insertion hole h2 communicating with each recess 14 is provided on the bottom surface of the upper frame portion 1b.

  The left and right lower frame portions 1c of the back frame 1 are continuous with the left and right side frame portions 1a, and the front portion extends from the lower ends of the left and right side frame portions 1a to a position corresponding to the main axis j1. That is, the left and right lower frame portions 1c are partially located outside the left and right arms g1 in the back support G. In other words, the left and right lower frame portions 1c extend in the front-rear direction, and the front end portions extend to both sides of the support base C disposed below the seat D.

  The left and right lower frame portions 1c are provided at their front portions with concave portions 15 that are open on the front side and inside, and into which both ends of the main shaft j1 are inserted. The recess 15 constitutes a portion for accommodating the main shaft j1. A recessed step 15c is formed on the opening end face on the front end side of the recess 15. A plurality of wall-shaped mounting ribs 15a externally fitted to the bush g3 are provided in the recess 15 at intervals in the left-right direction. Each mounting rib 15a is provided with a cutout 15b that can receive the bush g3 from the front side.

  The left and right lower frame portions 1c have a curved shape so as to gradually rise rearward in a side view. The left and right lower frame portions 1c are in a rearwardly inclined form in a side view. The left and right lower frame portions 1c are provided with bearing projections 16 having shaft holes a3 forming the positioning mechanism 6 on the upper surface side in the rear portions.

  The lower connecting portion 1d of the back frame 1 is for rigidly connecting the left and right lower frame portions 1c to each other, and includes an upper plate portion 17 arranged on the mounting plate g2 of the back support G, and an upper plate portion And a back plate portion 18 hanging downward from a lower edge of the back plate 17. The upper plate portion 17 is provided with a plurality of bolt insertion holes h3, and a bolt v1 inserted through the bolt insertion holes h3 from above is screwed into a nut portion (not shown) on the mounting plate g2 side to thereby form the back frame 1. Can be fixed to the back support G. The lower connecting portion 1d has an upper plate portion 17 through which an operating force transmitting wire w provided between the rearward locking mechanism I and the rearward locking operation lever d5 provided on the seat D is inserted. The wire insertion hole a4 is formed.

  The side frame portion 1a and the lower frame portion 1c which constitute the back frame 1 are integrally continuous so as to form an S shape in a side view. The lower frame portion 13 and the lower frame portion 1c in the side frame portion 1a have a U shape in a side view, and the side frame portion 1a and the lower frame portion 1c are integrally connected via a bent portion 19. are doing.

  The side frame portion 1a and the bent portion 19 are substantially rectangular in cross-section, and are formed so that the front side faces obliquely inward and the rear side faces obliquely outward. . That is, the side frame 1a and the bent portion 19 include an inwardly inclined surface m1 that is inclined inward on the front side, and an outwardly inclined surface m2 that is inclined outwardly on the back side. .

  The left and right side frame portions 1a of the back frame 1 described above are structurally connected only by the upper frame portion 1b. That is, the side frame portion 1b and the lower frame portion 1c (hereinafter, the side frame portion 1b and the lower frame portion 1c are collectively referred to as “side frame”) integrally and vertically continuous in the front view and the rear view. , Left and right, and the left and right side frames (1b, 1c) are integrally connected by an upper frame portion 1b. That is, the upper frame portion 1b and the left and right side frames (1b, 1c) form a downward U-shaped portion as viewed from the front. In this embodiment, the left and right side frames (1b, 1c) are integrally connected by a lower connecting portion 1d, but the lower connecting portion 1d may be separate.

<Hiding member 2>
The concealing member 2 is disposed on the front side of the lower frame portion 1c of the back frame 1, and closes the front side of the recess 15 of the lower frame portion 1c. More specifically, the concealing member 2 is made of a synthetic resin, and has a plate-shaped concealing member main body 21 and protrudingly provided on an inner surface of the concealing member main body 21 and directly or directly on the main shaft j1 in the recessed portion 15. And a mounting arm 22 which is indirectly involved. In this embodiment, the mounting arm 22 is indirectly engaged with the main shaft j1 via the bush g3, and can be fitted onto the bush g3 by utilizing the elastic deformation of the member.

  The concealing member main body 21 has a shape slightly curved so as to protrude toward the front side, and is set to a size that fits into the recessed step 15c of the recessed portion 15 of the back frame 1. The concealing member main body 21 is set to have such a thickness that, when fitted to the recessed step portion 15c, its outer surface is substantially flush with the outer surface of the lower frame portion c1 around the recessed portion 15.

  The mounting arm 22 is a plate-shaped one protruding rearward from the concealing member main body 21 and fitted to the bush g3 while being inserted into the gap sm formed between the mounting ribs 15a of the concave portion 15. It is. Each mounting arm 22 has a cutout portion 23 that opens rearward and can receive the bush g3 from the front side. The notch portion 23 has an inner opening width w1 set to a value substantially equal to the outer diameter of the bush g3, and an opening end side opening width w2 set to a value smaller than the outer diameter of the bush g3. Therefore, when these mounting arms 22 are pushed into the recessed portions 15 of the lower frame portion 1c, the distal ends of the mounting arms 22 are temporarily elastically deformed outward, and then are fitted to the bush g3. In the mounted state, the concealing member main body 21 is stably held by the recessed step 15c. In a state where the concealing member 2 is mounted on the concave portion 15 of the back frame 1, the mounting rib 15a of the concave portion 15 and the mounting arm 22 of the concealing member 2 are positioned in the axial direction of the main shaft j1, that is, in the left-right direction. Are different from each other.

  In the concealing member 2 having the above configuration, when the back frame 1 is rotated by the backward tilting operation or the like, the outer edge of the concealing member main body 21, that is, mainly the upper and lower edges are engaged with the recessed step portion 15c of the back frame 1. , And can rotate integrally with the back frame 1.

<Front back frame 3>
The front back frame 3 has an upper end and a lower end supported by the back frame 1 via connecting portions. The front back frame 3 has a continuous frame shape when viewed from the front, and a backrest surface is formed by the tension member 4 so as to substantially match the shape of the frame. The front back frame 3 is configured to be able to take a front position (f) and a rear position (r) by a positioning mechanism 6 described later. The front back frame 3 includes a frame body K and a plate L attached to the frame body K. The front back frame 3 is made of a material and a shape so as to be easily deformed as compared with the back frame 1, and has a protruding portion 32 protruding most forward in an intermediate portion thereof. The front back frame 3 has a side frame portion 3a, which is a frame having a substantially U-shape in side view.

  The frame body K is a continuous frame formed of a synthetic resin, and includes left and right side frame portions 3a, an upper frame portion 3b provided between upper ends of the left and right side frame portions 3a, A lower connecting frame portion 3c provided between lower ends of the side frame portions 3a.

  The left and right side frame portions 3a of the front back frame 3 are provided with mounting grooves mz on the outer surface for fastening the band-shaped member 41 as an edge of the tension member 4, and include an upper frame portion 31 inclined rearward in a side view. In the side view, the lower frame portion 33 inclined forward is connected to the front frame via the most protruding portion 32 protruding forward. At the lower ends of the left and right side frame portions 3a, a bearing projection 35 having a shaft hole a6 constituting the positioning mechanism 6 is provided in a protruding manner.

  The upper frame portion 31 constituting the side frame portion 3a is set to have a structure that is more flexible than the lower frame portion 33. In other words, the upper frame portion 31 is configured to be easily elastically deformed rearward with the protruding portion 32 located at the upper end of the lower frame portion 33 as the center of rotation.

  The lower frame portion 33 constituting the side frame portion 3a is formed so as to be gradually displaced inward downward. In other words, the left and right lower frame portions 33 are arranged so as to form a lower constriction in which the separation distance gradually decreases downward. The front surface of the lower frame portion 33 is provided with a groove-shaped recess a5 for positioning the lumbar support 5.

  The upper frame portion 3b of the front back frame 3 is integrally provided between the upper ends of the left and right side frame portions 3a, and has a curved shape so as to project rearward. The upper frame portion 3b is provided with an element constituting an upper connection portion for attaching the upper end portion of the back frame 1. That is, on the back surface of the upper frame portion 3b, the projection 36 that fits into each of the concave portions 14 of the back frame 1 is formed. Each projection 36 is provided so as to protrude rearward, and has a screw hole h4 in a vertical direction. These projections 36 are fitted into the recesses 14 of the back frame 1, and then the bolts v4 inserted from below are screwed into the screw holes h4, whereby the upper frame portion 3b of the front back frame 3 is screwed. Are fixed to the upper frame portion 1b of the back frame 1. On the upper surface of the upper frame portion 3b, a mounting groove mz for fixing the tension member 4 is provided, and both ends are continuous with the mounting groove mz of the side frame portion 3a.

  The lower connecting frame portion 3c of the front back frame 3 is provided between the lower end portions of the left and right side frame portions 3a, and has a curved shape so as to project rearward in plan view. The lower connection frame 3c is provided with a plurality of bosses n1 having screw holes for mounting the plate L on the front surface thereof at intervals in the left-right direction.

  The plate L is attached to substantially the entire front surface side of the lower connection frame portion 3c in the frame body K and a part of the front surface side of the side frame portion 3a. Can be supported. The plate L includes a plate body 3d that covers the front surface of the lower connection frame portion 3c, and both end portions 3e provided integrally on both sides of the plate body 3d.

  The plate body 3d includes a front wall 37 whose upper part is in contact with an upper part of the front surface of the lower connection frame part 3c, and a rear wall 38 which is in contact with a lower part of the front surface of the lower connection frame part 3c. .

  The lower portion 37b of the front wall 37 is spaced apart from the front side of the rear wall 38. A mounting groove mz which is opened downward is formed between the rear wall 38 and the lower portion of the front wall 37, and the lower edge 41 of the tension member 4 is mounted in the mounting groove mz. .

  Near the boundary between the upper portion 37a and the lower portion 37b of the front wall 37, a bolt holding portion h5 corresponding to the boss portion n1 of the lower connection frame portion 3c is formed. Further, a portion corresponding to the bolt holding portion h5 in the lower portion 37b of the front wall 37 is cut out downward so as to screw the bolt v5 to the boss portion n1 of the lower connection frame portion 3c through the bolt holding portion h5. A cutout portion 37c is provided.

  Both end portions 3e face the front surface of the lower end portion of the side frame portion 3a via the gap sk. In other words, a gap sk for attaching the lumbar support 5 is formed between the back surface of the both end portions 3e and the front surface of the side frame portion 3a of the front back frame 3.

  Both ends 3e are provided with claw members 39, which are engaging elements for holding the lumbar support 5. At both ends 3e, a slit s1 having an upward U-shape is formed, and a portion surrounded by the slit s1 is a claw member 39 which can be elastically deformed in the thickness direction. These claw members 39 are provided with projections (not shown) which are elastically engaged with the claw receiving portions 57 of the lumbar support 5 on the back side.

<Tension member 4>
The tension member 4 is formed by fastening a band-shaped member 41 to the periphery of a mesh-like cloth capable of forming a backrest surface by sewing or the like. The tension member 4 is tensioned on the front surface of the front frame 3 by engaging a band-shaped member 41 as an edge thereof with a mounting groove mz provided around the front frame 3.

  The tension member 4 is located in front of the lumbar support 5. For this reason, the tension member 4 in this embodiment can exert the function of restricting the movement of the lumbar support 5 to the front side with respect to the front back frame 3, that is, the function of preventing the lumbar support 5 from coming off with respect to the front back frame 3. It has become.

<Lumbar support 5>
The lumbar support 5 is for mainly supporting the waist portion of the occupant from the back side. In this embodiment, the lumbar support 5 is retrofitted to the front frame 3 on which the tension member 4 is stretched. It is configured to be able to. Here, “retrofitting” does not mean mounting after the stage at which the chair A reaches the consumer, but more specifically, after the backrest H on which the tension member 4 is provided is configured. , Which means mounting after the tension member 4 is stretched on the front frame 3.

  The lumbar support 5 is disposed between the left and right side frame portions 3a of the front back frame 3 constituting the backrest H, and is provided at a lower portion of the front back frame 3 which is set to have relatively higher rigidity than other portions. Installed. In other words, both ends of the lumbar support 5 are attached to the lower frame portion 33 of the side frame portion 3a. The lower frame portion 33 is set to have relatively high rigidity, so that the lumbar support 5 does not easily come off even when receiving the weight of the occupant. That is, the lower frame portion 33 can stably support the lumbar support 5 and can suitably exhibit the function as the lumbar support 5.

  The lumbar support 5 includes a curved plate-shaped lumbar support main body 5a that receives a load from a user and mounting portions 5b provided at both ends of the lumbar support main body 5a, and is integrally formed of synthetic resin. ing.

  The lumbar support body 5a has a plate shape, and has a substantially horizontal band-shaped region 51 whose left and right ends are continuous with the mounting portion 5b, and an upper region 52 extending upward from the upper edge of the band-shaped region 51. It is made. Further, the lumbar support main body 5a includes a lower region 53 extending downward from a lower edge of the band-shaped region 51.

  In other words, the lumbar support main body 5a is located at the middle part in the left-right direction and has a substantially horizontally elongated rectangular shape in front view, and diagonally downward and outward from the lower left and right corners of the main part 54, respectively. And a continuous portion 55 extending toward the front. At the extension end of the continuous portion 55, a mounting portion 5b formed in a rectangular shape in a front view is integrally provided. The band-shaped region 51 is constituted by a part of the main part 54 and a part of the continuous part 55. The upper region 52 mainly includes an upper portion of the main portion 54. The lower region 53 is constituted by a part of the continuous portion 55.

  The band-shaped region 51 is a portion that extends linearly in the left-right direction when viewed from the front, and the mounting portions 5b are integrally provided over the entire region at both end edges. The band-shaped region 51 cooperates with the side frame portion 3a of the front back frame 3 and serves as a main portion for receiving the load of the occupant. 23 to 25, the band-shaped region 51 is shaded for easy understanding. The band-shaped region 51 connects the left and right mounting portions 5b in a straight line, and the strength of the lumbar support 5 as a whole is received by the left and right mounting portions 5b to receive the load of the occupant.

  The upper region 52 is set to have such a size and shape that a space sp is formed between both side edges thereof and the left and right side frame portions 3 a of the front back frame 3. In other words, the upper region 52 extends upward from the entire upper edge of the belt-shaped region 51, and has a form in which the width dimension in the left and right direction gradually decreases upward. A space sp is formed between both side edges of the upper region 52 and the upper frame portion 31 of the side frame portion 3a. The upper region 52 is likely to bend rearward from the vicinity of the boundary with the belt-shaped region 51 as a base when receiving a load of a seated person.

  The upper region 52 is set so as to be arranged at a height position corresponding to the upper frame portion 31 of the front back frame 3, and is set to be more easily bent in the thickness direction than the belt-shaped region 51. In this embodiment, the upper region 52 has a hat shape in a front view in which a lower end portion is configured to be longer than the upper portion. The upper region 52 has a curved shape so as to be convex rearward in a plan view corresponding to the shape of the tension member 4 together with the band-shaped region 51. The upper region 52 is formed with two concave portions 52a extending in the left-right direction at two upper and lower portions on the back side, and is configured to be easily bent in the thickness direction. The upper region 52 has a shape in which an upper edge portion is warped rearward in a side view. That is, the upper region 52 is provided with the rear warp portion 52b at the upper end.

  The lower region 53 extends downward from the lower edge of the belt-shaped region 51. The lower region 53 is provided between the vicinity of both ends of the lower edge of the band-shaped region 51 and the mounting portion 5b. The lower region 53 has a role of securing the mounting strength between the band-shaped region 51 and the mounting portion 5b.

  The attachment portions 5b are provided at both ends of the lumbar support main body 5a and are attached to the lower frame portion 33 of the side frame portion 3a and both ends 3e of the plate L. The attachment portion 5b is an elongated plate-like member extending below the band-shaped region 51 and the lower region 53 along the lower frame portion 33, and has a rib-shaped rearwardly projecting portion 56 on its back surface. The lower end is provided with a square hole-shaped claw receiving portion 57 with which the claw member 39 of the plate L is engaged.

  The mounting portion 5 b is arranged between the front surface of the lower frame portion 33 of the front back frame 3 and the back surface of the tension member 4. The attachment portion 5b is attached to the front frame 3 with the tension member 4 stretched by moving the lumbar support 5 from the rear side. That is, the mounting portion 5b of the lumbar support 5 is inserted between the tension member 4 and the frame body K while the lumbar support 5 is pressed against the back surface of the tension member 4 from the rear side of the backrest H. I do. With this operation, in the final stage, the protrusion 56 of the mounting portion 5b fits into the recess a5 of the lower frame portion 33, and at the same time, the claw receiving portion 57 of the mounting portion 5b engages with the lower frame main body K. The gap sk between the portion 33 and both ends 3e of the plate L is interrupted, and the claw member 39 of the plate L is engaged. In this manner, the mounting portion 5b is located between the lower frame portion 33 and the tension member 4, and the protruding portion 56 and the concave portion a5 are engaged with the claw receiving portion 57 and the claw member 39, respectively. In this state, the lumbar support 5 is attached to the front back frame 3 so as not to come off. In other words, the protrusion 56 and the recessed part a5 constitute a detachment preventing element, and the claw receiving part 57 and the claw member 39 constitute an engaging element.

  The detachment preventing element is for receiving a load applied to the lumbar support 5, and is provided between the mounting portion 5b and the front back frame 3 as a frame. In this embodiment, the disengagement prevention element is constituted by a concave portion a5 extending along the longitudinal direction of the front back frame 3 and a projecting portion 56 provided on the lumbar support 5.

  The engagement element is for attaching the lumbar support 5 to the front back frame 3 as a frame by utilizing elastic deformation of the member. In this embodiment, the engagement element is constituted by a claw member 39 provided on the front back frame 3 and a claw receiving portion 57 provided on the lumbar support 5.

  In this embodiment, the positions of the engagement elements (39, 57) and the positions of the disengagement prevention elements (a5, 56) are separately provided. Then, fixing when the lumbar support 5 is attached to the front back frame 3 is mainly performed by the engagement elements (39, 57), and the lumbar support 5 is attached to the load of the occupant after the lumbar support 5 is attached to the front back frame 3. The resistance is made to function mainly by the separation preventing elements (a5, 56). For this reason, the configuration of the mounting portion 5b and the front back frame 3 can be suitably provided separately for each function.

  The front frame 3 is attached to the connection between the front frame 3 and the back frame 1 holding the lumbar support 5 as described above, that is, the connection between the lower portion of the front frame 3 and the back frame 1. Is provided with a positioning mechanism 6 which can be selectively positioned at two different positions.

<Positioning mechanism 6>
The positioning mechanism 6 can select the position of the lower end portion of the front back frame 3 at the front position (f) or the rear position (r) and position it. It is configured such that it can be stably positioned at either the position (f) or the rear position (r).

  The positioning mechanism 6 connects the left and right links 6 a and 6 b pivotally supported so as to be able to rotate in the front-rear direction with respect to the back frame 1, and the rotating ends of the left and right links 6 a and 6 b with the front back frame 3. And a tip shaft j7 which is a pivoting element pivotally connected to the lower end. The left and right links 6a and 6b can rotate only between a front position (a), which is a front dead center inclined forward, and a rear position (c), which is a rear dead center inclined backward. Is set.

  Between the front position (a) and the rear position (c) of the left and right links 6a and 6b, an intermediate position as a conceivable point where the direction of the rotational bias of the front back frame 3 on the left and right links 6a and 6b is reversed. (B) is set. In other words, the intermediate position (b) exists between the front position (a) and the rear position (c) in the left and right links 6a, 6b. The upper end of the front back frame 3 has the left and right links 6a, 6b in comparison with the amount of elastic deformation of the front back frame 3 when the left and right links 6a, 6b are at the front position (a) or the rear position (c). The front frame 3 is connected to the upper end of the back frame 1 so as to increase the amount of elastic deformation of the front frame 3 at the intermediate position (b).

  The positioning mechanism 6 is provided between a rearwardly inclined portion of the lower portion of the back frame 1 and a lower end portion of the front back frame 3. The positioning mechanism 6 includes left and right links 6 a and 6 b provided on the back frame 1 and arranged in a pair on the left and right, and pivotal ends of these left and right links 6 a and 6 b at the lower end of the front back frame 3. It has a tip shaft j7 as a pair of left and right pivot elements, which are pivotally connected to both side portions, and an operation lever 6c for directly rotating the left link 6a which is one of the links.

  The left link 6a (located on the left side in a front view) is rotated in the front-rear direction by an operation force applied to the operation lever 6c, and includes an inner link member 61 and an outer link member 62. .

  The lower part of the inner link member 61 is in contact with the inner surface of the bearing protrusion 16 in the back frame 1, and the upper part is in contact with the inner surface of the bearing protrusion 35 in the front back frame 3. The inner link member 61 includes a base shaft j6 inserted through the shaft hole a3 of the bearing protrusion 16 in the back frame 1 and a distal shaft serving as a pivotal element inserted through the shaft hole a6 of the bearing protrusion 35 in the front frame 3. j7. At an intermediate position of the inner link member 61, a bolt insertion hole h6 is formed.

  The outer link member 62 has a lower portion in contact with the outer surface of the bearing protrusion 16 in the back frame 1 and an upper portion in contact with the outer surface of the bearing protrusion 35 in the front frame 3. It has a base-side fitting hole a7 in which the through-end fits, and a distal-side fitting hole a8 in which the through-end of the distal shaft j7 fits. A spacer projection 63 is provided at an intermediate position between the outer link members 62 to keep the distance between the outer link members 62 and the inner link members 61 constant. The spacer projection 63 has a screw hole n2 into which the bolt v6 inserted through the bolt insertion hole h6 is screwed. That is, the inner link member 61 and the outer link member 62 are joined by screwing the bolt v6 into the screw hole n2.

  The spacer projection 63 has a front edge or a rear edge that can abut on the front or rear surface of the bearing projection 16 on the back frame 1, and the left link 6a moves from the front position (a) to the rear position ( It has a function of regulating the rotation range so that it can rotate only up to c). In this embodiment, as shown in FIGS. 9 and 10, the left link 6a at the front position (a) and the left link 6a at the rear position (c) are centered on the virtual center line ct on the base axis j6. It is set so that it can take a posture that is substantially symmetrically inclined.

  A prismatic boss portion h7 is provided on the outer surface of the proximal end portion of the outer link member 62 such that the axis coincides with the axis of the proximal-side fitting hole a7. The base end of the operation lever 6c is fitted to the boss h7, and is prevented from being removed from the boss h7 by a bolt v7. A ring member 6d is interposed between the periphery of the base end of the operation lever 6c and the outer link member 62. The operation lever 6c connected to the outer link member 62 can rotate integrally with the outer link member 62.

  The right link 6b (located to the right in front view) has a configuration similar to that of the above-described left link 6a, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

  The right link 6b differs from the left link 6a in that the outer link member 62 is not provided with an operation lever. Here, the front link 3 is operated by operating the operation lever 6c to directly connect the left link 6a to a lower end portion thereof, that is, a portion between the left bearing projection 35 and the right bearing projection 35 in the front back frame 3. The rigidity is such that the operating force when turned to the right can be transmitted to the right link 6b. Therefore, the operation force of the operation lever 6c attached to the left link 6a can be reduced without providing an operation lever on the right link 6b or providing a special mechanism for connecting the left and right links 6a, 6b. This is transmitted to the right link 6b via the front and back frames 3.

  The operation related to the positioning mechanism 6 described above will be described as follows.

  As shown by the imaginary lines in FIGS. 1, 4, 5 and 8 to 10, when the left and right links 6a, 6b are at the front position (a), the left and right links 6a, 6b It is urged in the direction of leaning forward by receiving the elastic repulsive force from, and is stably held at the front position (a). In this state, the lower part of the front back frame 3 is held at a position away from the back frame 1 in a side view in a side view. In this state, when the operation lever 6c provided on the left link 6a is rotated backward, the left link 6a passes from the front position (a) through the intermediate position (b) to the rear position (c). As a result, the lower portion of the front back frame 3 moves to a position where it partially covers the back frame 1 in a side view. At this time, the right link 6b follows the movement of the lower end portion of the front frame 3 and rotates from the front position (a) through the intermediate position (b) to the rear position (c). Become. The left and right links 6a, 6b rotate while elastically deforming the protruding portion 32 of the front back frame 3 so that the degree of bending of the protruding portion 32 increases, and a predetermined intermediate position as shown by a solid line in FIG. Beyond (b), the elastic repulsion force for returning the protruding portion 32 of the front back frame 3 from immediately thereafter acts as a force for rotating the left and right links 6a and 6b backward. The left and right links 6a and 6b that have received the elastic repulsive force of the front back frame 3 are positioned and stably held when reaching the rear position (c) as shown by the solid lines in FIGS. Become.

  As shown by the solid line in FIG. 8, when the left and right links 6a and 6b are held at the rear position (c), the rear edge of the side frame 3a of the front frame 3 It moves to a position where it covers the side frame portion 1a of the back frame 1 in side view, and is positioned. In other words, when the left and right links 6a and 6b are held at the rear position (c), the front and back frames are compared with the state where the left and right links 6a and 6b are held at the front position (a). The lower frame 3, that is, the side frame portion 3 a of the front back frame 3, the lower connection frame portion 3 c, and the plate L are close to the back frame 1.

  In this embodiment, the upper end of the front back frame 3 is fixed to the back frame 1 by bolts v4. For this reason, when the left and right links 6a, 6b rotate from the front position (a) to the rear position (c), the upper end of the front back frame 3 becomes the rotation center, that is, the base end, and hardly moves. The lower end of the front frame 3 moves rearward as a rotating end. The height position of the rotating end when the left and right links 6a and 6b are at the front position (a) and the height position of the rotating end when the left and right links 6a and 6b are at the rear position (c) are as follows. They are set to be almost the same.

  In this embodiment, when the front back frame 3 is at the front position (f), the lumbar support 5 supported by the front back frame 3 has the band-shaped region 51 located on the front side of the upper region 52, When the frame 3 is at the rear position (r), the upper region 52 is located on the front side of the belt-shaped region 51. In other words, the lumbar support 5 when the front back frame 3 is at the rear position (r) has a more inclined posture than when the front back frame 3 is at the front position (f).

  The positioning mechanism 6 sets the rotation range of the left and right links 6a and 6b, thereby setting the height position of the rotation end at the front position (a) and the height position of the rotation end at the rear position (c). The relative position between the side frame portion 3a of the front frame 3 and the lumbar support 5 depends on whether the left and right links 6a and 6b are at the front position (a) and at the rear position (c). Can be changed. That is, in the state where the left and right links 6a and 6b are at the front position (a) and the state where the left and right links 6a and 6b are at the rear position (c), the side view shape of the front back frame 3 is made different. Can be done. Specifically, the relative angle between the upper frame portion 31 and the lower frame portion 33 of the side frame portion 3a constituting the front back frame 3 (that is, the degree of bending of the protruding portion 32) changes, and The relative position between the upper region 52 of the lumbar support 5 supported by the portion 33 and the upper frame portion 31 changes. That is, the lumbar support 5 is mounted at a position where the relative position of the upper region 52 to the upper frame portion 31 changes with the deformation of the side frame portion 3a of the front back frame 3.

  For example, the relative angle between the upper frame portion 31 and the lower frame portion 33 in a state where the left and right links 6a and 6b are positioned at the rear position (c) is determined by using the left and right links 6a and 6b as the front position (a). It is also possible to make the relative angle between the upper frame portion 31 and the lower frame portion 33 in a state where the upper frame portion 31 is positioned at a larger angle. That is, by rotating the left and right links 6a, 6b from the front position (a) to the rear position (c), the lumbar support 5 performs a forward tilting operation, and the upper region 52 of the lumbar support 5 is moved. , Will be relatively close to the upper frame portion 31 in side view. When the left and right links 6a and 6b are at the rear position (c), the upper region 52 of the lumbar support 5 is tighter in a no-load state than when the left and right links 6a and 6b are at the front position (a). The member 4 will approach the back side.

<< Backward tilt lock mechanism I >>
The backward tilt lock mechanism I is for locking the backrest H at a desired backward tilt position, and is provided between the back support G and the support base C in this embodiment.

  The backward tilt lock mechanism I includes a lock unit M which is a main part of the rear tilt lock mechanism I on the back support G side, and the engaging member 7 of the lock unit M is selectively engaged on the support base C side. Receiving member N having a plurality of engaging portions c8.

  The lock unit M is a lock position (h) where the backrest structure F (the back support G and the backrest H) prohibits the backward leaning operation with respect to the support base C or a free position that allows the backward leaning operation of the backrest structure F. An engagement member 7 that can take a position (i), a drive mechanism 8 that drives the engagement member 7 between a lock position (h) and a free position (i), and a drive mechanism 8 and an engagement member 7 And a supporting member 9 for supporting the above.

  The lock unit M has a plurality of parts assembled and assembled on the support member 9. In the manufacturing stage of the chair A, the lock unit M is assembled on an independent specific manufacturing line and independently checks the operation on the manufacturing line. Is available. In other words, the lock unit M forms a package in which the engagement member 7 and the drive mechanism 8 are held by the support member 9 as a base body, and is configured to be applicable to other chairs as they are. Note that, at the completion stage of the chair A, the first housing 9a constituting the support member 9 of the lock unit M is joined to the back support G by welding.

  Hereinafter, the configuration of the lock unit M will be described in detail.

  The engagement member 7 is a plate-like member having a substantially rectangular shape in a plan view and having an engagement protrusion 71 provided on the distal end side. It is supported by. A long hole 72 extending in a direction orthogonal to the advance / retreat direction is formed in an intermediate portion of the engagement member 7. In the center of the rear edge of the engaging member 7, a projection 73 serving as a spring retainer for engaging the front end of the locking spring 81 is provided.

  The drive mechanism 8 relates to a locking spring 81 for urging the engaging member 7 in the locking direction, that is, the direction of the engaging portion c8, and an operating force transmitted from the operating lever d5 for backward tilt locking via the wire w. And an operation conversion mechanism 82 that converts the force into a force to retreat the joint member 7.

  The locking spring 81 is of a compression coil type, and is interposed between the engaging member 7 and a rear wall 96 of a second housing 9b described later.

  The operation converting mechanism 82 includes an operation arm 83 whose base end is rotatably supported by the second housing 9 b constituting the support member 9 and whose distal end is connected to the wire w. A lock release spring 86 in which an operation end 86b that rotates with the rotation of the operation arm 83 is engaged with the elongated hole 72 is provided.

  The operation arm 83 is supported by a shaft j8 provided in the second housing 9b and rotates in the front-rear direction. A shaft hole a9 with which the shaft j8 of the second housing 9b is engaged is provided at a base end portion. A wire connecting portion 84 for connecting the tip of the wire w to the rotating end is provided. At the base end of the operation arm 83, a spring mounting portion 85 for mounting the unlocking spring 86 is provided. The unlocking spring 86 includes a spring body 86a wound in a coil shape, one coil end 86b extending from one end of the spring body 86a, and the other coil end 86c extending from the other end of the spring body 86a. In this embodiment, one coil end 86b forms an operating end 86b for biasing the engaging member 7. The spring mounting portion 85 is provided at a base end of the operation arm 83 to accommodate the spring main body 86a in alignment with the axis of the shaft hole a9, and the spring main body 86a accommodated in the notch 85a. And a coil end holding portion 85b for holding the other coil end 86c extending from the coil end 86c.

  The support member 9 is a basic structure for unitization that enables a plurality of parts, that is, the engagement member 7 and the drive mechanism 8 to be collectively handled in the manufacturing stage of the chair A. It has a first housing 9 a that slidably supports the member 7 and a second housing 9 b that supports the drive mechanism 8.

  The first housing 9 a has a channel shape opened upward, and has a bottom wall 91, a front wall 92 extending upward from a front edge of the bottom wall 91, and a rear wall 91. And a rear wall 93 extending upward from the edge.

  The bottom wall 91 includes a window 91a for passing the operating end 86b of the unlocking spring 86, a housing mounting hole 91b for mounting the second housing 9b, and a back support G including a rearward tilt locking mechanism I. And a cover mounting hole 91c for mounting a cover g7 that covers the lower surface side of the rear part of. A slit s2 extending in the left-right direction is formed in the front wall 91, and the front end side of the engaging member 7 is held in the slit s2 so as to be slidable in the front-rear direction. A slit s3 extending in the left-right direction is formed in the rear wall 92, and the rear end side of the engaging member 7 is slidably held in the front-rear direction in the slit s3. That is, the engaging member 7 is held by the first housing 9a so as to be able to advance and retreat in the front-rear direction while penetrating the front wall 92 and the rear wall 93 of the first housing 9a.

  The second housing 9 b is provided with a bottom wall 94, side walls 95 extending upward from left and right side edges of the bottom wall 94, and extending upward from a rear edge of the bottom wall 94. It has a wall 96 and a mounting flange 97 extending rearward from the upper edge of the rear wall 96.

  The bottom wall 94 is provided with a cross rib-shaped shaft j8 that pivotally supports the operation arm 83 of the drive mechanism 8 so as to be able to turn horizontally. That is, the operation arm 83 is rotatably attached to the second housing 9b by engaging the shaft hole a9 of the operation arm 83 holding the unlocking spring 86 with the shaft j8.

  The side wall 95 includes an upward edge 95a that contacts the lower surface of the bottom wall 91 of the first housing 9a, and a forward edge 95c for locking the rear end of the engaging member 7 at the free position (i). An elastic claw 95b that engages with the housing mounting hole 91b of the first housing 9a is protruded from the upward edge 95a.

  The rear wall 96 includes a front wall 96a facing the front and an inclined wall 96b facing diagonally forward. The front wall 96a is provided with a spring retainer 96c for holding a rear end of the locking spring 81. ing. A window 96d is formed in the inclined wall portion 96b, and a mounting portion 96e for mounting one end of a tube t that holds the wire w is formed on a lower edge portion of the window 96d.

  The mounting flange 97 is in contact with the lower surface of the mounting plate g2 of the back support G, and includes a bolt insertion hole h8 in which a bolt v8 for fastening the second housing 9b to the mounting plate g2 is mounted. ing.

  In this embodiment, the first housing 9a is made of metal, and the second housing 9b is made of synthetic resin. The first and second housings 9b are arranged between the left and right arms g1 of the back support G.

  When the chair A is completed, the first housing 9a is connected to the left and right arms g1 by welding, and also functions as a strength member. Even after the chair A is completed, the second housing 9b housing the drive mechanism 8 is removed from the back support G and the first housing 9a by removing the bolt v8 and deforming the elastic claws 95b. You can do it.

  The engaging member 7 of the lock unit M configured as described above selectively engages with any one of the plurality of engaging portions c8 of the receiving member N provided at the rear end of the support base C, and The backrest structure F can be locked at a desired backward tilt position.

  The receiving member N is a wall-shaped member that also serves as the rear wall c7 of the support base C, and includes a plurality of sets of engaging portions c8 spaced apart in the vertical direction. In this embodiment, the receiving member N includes a pair of left and right engagement portions c8 provided in the upper stage, a pair of left and right engagement portions c8 provided in the middle stage, and a pair of left and right engagement portions provided in the lower stage. And a joint c8. A pair of left and right engaging portions c8 provided at the upper stage is for locking the backrest H at the initial position shown in FIGS. 1 to 6, and is constituted by a concave stepped portion. The middle and lower engaging portions c8 are formed by recessed through holes.

  Next, the operation of the backward tilt lock mechanism I will be described.

  When the wire w is not pulled by the operation lever d5 for backward tilt locking, the operation arm 83 is held at the front position (j), and the engagement member 7 is moved forward by the urging force of the locking spring 81. Elastic biased. Therefore, when the engaging member 7 faces the engaging portion c8 of the receiving member N due to the rotation of the backrest H, the engaging member 7 moves forward, and the engaging portion c8 faces the engaging protrusion 71. Will be engaged. When the engaging projection 71 is engaged with the engaging portion c8, the backrest H cannot be tilted backward.

  When the operation of unlocking the back is performed by pulling the wire w by the operation lever d5 for locking the backrest from the state where the backrest H is locked rearward, the operation force is applied via the wire w. This is transmitted to the operation arm 83, and the operation arm 83 rotates rearward, that is, toward the rear position (k). As the operation arm 83 rotates rearward, the operation end 86b of the unlocking spring 86 also moves rearward, and the engaging member 7 retreats to cause the engaging protrusion 71 to engage with the engaging portion c8. The engagement is released. In a state where the engagement between the engagement protrusion 71 and the engagement portion c8 is released, the backrest H can be freely tilted backward. At this time, the operation lever d5 for the backward tilt lock can be fixed in a state where the wire w is pulled, and in this case, the occupant can freely move the backrest H by his own load. Can be tilted.

  Even if the operation arm 83 rotates toward the rear position (k), if the friction between the engaging member 7 and the receiving member N is large, the engaging member 7 cannot temporarily move backward. The operating end 86b of the unlocking spring 86 is left with the engaging member 7 at the lock position (h). In this state, the operation end 86b of the unlocking spring 86 is restricted from moving backward by the engaging member 7 in a state where it does not move, and the elastic repulsive force in the unlocking direction is increased. In other words, when the operation end 86b of the unlocking spring 86 is left at the lock position (h) together with the engaging member 7, the elastic urging force of the unlocking spring 86 is applied to the engaging member 7 rearward. Will work. Therefore, at the moment when the friction between the engaging portion c8 and the receiving member N decreases due to the slight movement of the backrest H or the like, the engaging member 7 retreats backward by the elastic urging force of the unlocking spring 86, and the lock is released. Will be released.

<< Locking mechanism J >>
The locking mechanism J is for synchronously moving the seat D in response to the tilt of the backrest H, and is capable of moving the front portion of the seat support d1 back and forth at the front end of the support base C via the front link c9. In addition to the support, the rear portion of the seat D is pivotally supported by a rear link g4 provided on the back support G via a rear connection shaft j4.

  In the locking mechanism J in this embodiment, in the initial state, the front link c9 and the rear link g4 are each inclined forward, and when the backrest H is inclined backward, the seat D is entirely raised. It is a so-called weight sensing system configured as described above.

  As described above, the chair A according to the present embodiment has the lumbar support 5 disposed between the left and right side frame portions 3a of the front back frame 3, which is the frame constituting the backrest H. The lumbar support 5 includes a lumbar support main body 5a having a plate shape, and mounting portions 5b provided at both ends of the lumbar support main body 5a and mounted to the left and right side frame portions 3a. The lumbar support main body 5a integrally includes a substantially horizontal band-shaped region 51 whose left and right ends are continuous with the mounting portion 5b, and an upper region 52 extending upward from the upper edge of the band-shaped region 51. Therefore, it is possible to provide the chair A having the lumbar support 5 in which the upper region 52 bends favorably with respect to the belt-shaped region 51. That is, since the band-shaped region 52 extends substantially horizontally following the attachment portion 5b, the band-shaped region 52 can suitably play the role of receiving the load of the occupant in cooperation with the side frame portion 3a. The upper region 52 extending upward from the band-shaped region 52 can be suitably tilted or rotated rearward with respect to the band-shaped region 51.

  The upper region 52 has such a shape that a space sp is formed between both side edges and both side frame portions 3a. For this reason, since the upper region 52 has a mode in which only the lower end portion is supported by the band-shaped region 51, the upper region 52 is set so as to be able to bend appropriately with respect to the band-shaped region 51. I have.

  The upper region 52 extends upward from the entire upper edge region of the belt-shaped region 51, and has a form in which the left-right width dimension gradually decreases upward. For this reason, the upper edge portion 52 can give a favorable impression in appearance. Moreover, at the boundary between the belt-shaped region 51 and the upper region 52, stress when the load of the occupant is likely to be concentrated. In this embodiment, the portions where stress is easily concentrated are widely dispersed in the left-right direction. Therefore, the upper region 52 has a structure excellent in strength while having a configuration that is easily bent with respect to the band-shaped region 51.

  In other words, the upper region 52 has a hat shape in a front view. For this reason, a sufficient area for receiving the back of the occupant is secured at the center in the left-right direction of the upper region 52, and the lower portion of the upper region 52 is integrally connected to the band-shaped region 51 in a wide range in the left-right direction. It has become.

  The upper region 52 has a shape in which an upper edge portion is warped backward. In other words, the upper region 52 has a rear warp portion 52b. For this reason, the upper edge portion can smoothly contact the back of the seated person via the tension member 4, and the seated person can be provided with a sense of holding without discomfort.

  In this embodiment, a positioning mechanism 6 is provided between the lower end of the front frame 3 and the back frame 1. Therefore, when the left and right links 6a and 6b of the positioning mechanism 6 are rotated between the front position (a) and the rear position (c), the rear warp portion 52b is firstly provided on the back surface of the tension member 4. Can be abutted. In other words, according to the configuration of this embodiment, the edge of the lumbar support 5 and the tension member 4 are prevented from being caught and the tension member 4 is preferably prevented from being damaged. I have.

  The attachment portion 5b has a shape extending below the band-shaped region 51 along the side frame portion 3a. For this reason, the belt-shaped region 51 is suitably supported by the mounting portion 5b. Moreover, since the mounting portion 5b is suitably engaged with the side frame portion 3a in a wide range, the lumbar support 5 is suitably held by the front and back frames 3.

  The lumbar support main body 5a includes a lower region 53 extending downward from a lower edge of the band-shaped region 51, and the lower region 53 is provided between a portion near both ends of the lower edge of the band-shaped region 51 and the mounting portion 5b. It was done. For this reason, the connection mode between the belt-shaped region 51 and the mounting portion 5b is excellent in strength.

  Note that the present invention is not limited to the embodiment described in detail above.

  The frame is not limited to the front-back frame as in the above-described embodiment, as long as the frame has a frame shape or a frame-shaped portion. That is, the frame may be any part as long as it can constitute a backrest. In the above-described embodiment, the backrest has a configuration in which the front back frame is disposed on the front side of the back frame. However, the present invention is not limited to such a structure. May be configured.

  The frame does not have to be a tension member. In other words, the frame may support a cushioning material or a resin having a backrest surface formed of resin.

  The lumbar support may be formed integrally with the front frame by resin.

  The shape of the lumbar support body may be any shape as long as it has a band-shaped region and an upper region integrally. For example, the lumbar support body may have a convex shape in a front view.

  The attachment part may be any one that can be fixed to the side frame part. The present invention is not limited to the above-described embodiment. For example, the attachment portion is provided with a bolt insertion hole, and the attachment portion and the side frame portion are connected by screwing a bolt inserted through the bolt insertion hole to the side frame portion. There may be.

  In addition, the specific configuration of each unit is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

3 ... Frame (front frame)
3a ... side frame part 5 ... lumbar support 5a ... lumbar support main body 5b ... mounting part 51 ... band-shaped area 52 ... upper area 53 ... lower area

Claims (5)

A chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest,
The side frame portion includes left and right lower frame portions formed so as to be gradually displaced inward downward.
The lumbar support, which includes a lumbar support body which forms a plate shape, and a mounting portion mounted on the lower frame portion component of the right and left is provided at both ends of the lumbar support body,
The lumbar support body integrally has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region,
A chair in which the upper region extends upward from the entire upper edge region of the belt-shaped region, and the width dimension of the upper and lower regions gradually decreases upward. A chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest,
The side frame portion includes left and right lower frame portions formed so as to be gradually displaced inward downward.
The lumbar support, which includes a lumbar support body which forms a plate shape, and a mounting portion mounted on the lower frame portion component of the right and left is provided at both ends of the lumbar support body,
The lumbar support body integrally has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region,
The mounting portion has a shape along the longitudinal direction of the lower frame portion component of the left and right chair said is made extends below the strip-like region. A chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest,
The side frame portion includes left and right lower frame portions formed so as to be gradually displaced inward downward.
The lumbar support, which includes a lumbar support body which forms a plate shape, and a mounting portion mounted on the lower frame portion component of the right and left is provided at both ends of the lumbar support body,
The lumbar support body integrally has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region,
The lumbar support main body includes a lower region extending downward from a lower edge of the band-shaped region, and the lower region is provided between both ends near the lower edge of the band-shaped region and the mounting portion. Chair. A chair in which a lumbar support is arranged between side frame portions of a frame constituting a backrest,
The side frame portion includes left and right lower frame portions formed so as to be gradually displaced inward downward.
The lumbar support, which includes a lumbar support body which forms a plate shape, and a mounting portion mounted on the lower frame portion component of the right and left is provided at both ends of the lumbar support body,
The lumbar support body integrally has a substantially horizontal band-shaped region whose left and right ends are continuous with the mounting portion, and an upper region extending upward from an upper edge of the band-shaped region, and is convex in a front view. A chair that is shaped like a letter. The chair according to claim 1, 2, 3, or 4, wherein the upper region has a shape in which an upper edge portion is warped backward.

Images