JP6650094B2 - Chair - Google Patents

Description

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

  Conventionally, there are various chairs in which a mesh-like tension member is attached to a backrest (for example, see Patent Document 1). The mesh-shaped tension member has its edge engaged with the tension member mounting groove of the back frame constituting the backrest, and is stretched on the back frame.

  However, in the related art, when the back frame is formed by integral molding, a groove that is opened in a suitable direction may not be formed. Particularly, in the conventional device, it is difficult to form the downward tension member mounting groove in the back frame, and the tension member mounting groove is provided later by attaching another component to the back frame. .

JP 2010-252892 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a chair having a back frame in which a downward tension member mounting groove can be easily formed even in an integrally molded product.

  That is, the present invention has the following configuration.

  The invention according to claim 1 is a chair having a backrest in which a tension member is stretched on a back frame, wherein the back frame has left and right side frame members each having a tension member mounting groove opened outward. An upper frame member having a tension member mounting groove opened upward and connecting the upper portions of the left and right side frame members, a lower frame material connecting the lower portions of the side frame members, and a tension member opened downward. A chair which is an integrally molded product and has an intermediate connection frame member for connecting the left and right side frame members in a state where a cavity is formed between the left and right side frame members in a state where a cavity is formed between the left frame member and the lower frame member.

  The invention according to claim 2 is the chair according to claim 1, wherein lower portions of the left and right side frame members are shaped to be downwardly approaching in a front view.

  The invention according to claim 3 is the chair according to claim 1 or 2, wherein the intermediate connecting frame member is erected between portions of the left and right side frame members that are inclined forward in a side view.

According to a fourth aspect of the present invention, there is provided the chair according to the first, second or third aspect, wherein a plurality of the tension member mounting grooves are provided on the front side of the intermediate connecting frame member at intervals in the left-right direction.

  In the invention according to claim 5, a tension member mounting groove at an end opening downward is provided near a portion where the left and right side frame members and the intermediate connection frame member are connected. A chair according to 1, 2, 3 or 4.

  The invention according to claim 6, wherein the back frame has an upper frame-like portion in which an upper cavity is formed by the left and right side frame members, the upper frame member, and the intermediate connection frame member, and the left and right sides. The chair according to any one of claims 1, 2, 3, 4, and 5, further comprising a lower frame-shaped portion in which the lower cavity is formed by the frame material, the lower frame material, and the intermediate connection frame material. is there.

  In the invention according to claim 7, the left and right side frame members forming the upper frame-shaped portion have a U-shape projecting forward in a side view, and form the lower frame-shaped portion. 7. The chair according to claim 6, wherein the left and right side frame members are shaped like a letter protruding rearward in a side view.

  As described above, according to the present invention, it is possible to provide a chair having a back frame in which a downward tension member mounting groove can be easily formed even when integrally formed.

FIG. 1 is a perspective view showing an embodiment of the present invention. The front view in the embodiment. The right view in the embodiment. The rear view in the embodiment. The top view in the embodiment. The perspective view in the embodiment. XX sectional drawing in FIG. FIG. 3 is a sectional view taken along line YY in FIG. 2. FIG. 3 is a sectional view taken along line ZZ in FIG. 2. The front view which shows the back frame of the embodiment. The rear view which shows the back frame of the embodiment. FIG. 11 is a sectional view taken along line U-U in FIG. 10. VV sectional drawing in FIG. 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 exploded perspective view in the 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 has a chair body B and an optional hanger 9 attached thereto. The details will be described below.

<Chair body B>
In the chair body B, a support base 2 is rotatably provided on a leg 1, and a seat 3 is arranged on the support base 2, and a backrest 5 is supported on the support base 2 via a back support 4. Let me.

<Leg 1>
The leg 1 includes a plurality of radially arranged leg blades 11 having casters 111 at the distal ends, and leg posts 12 erected at the base end of the leg blades 11. The leg support 12 includes a gas spring (not shown) that can expand and contract in the vertical direction, and a cover 12a that conceals the gas spring. The gas spring supports the support base 2 so that the vertical position can be changed. .

<Support base 2>
The support base 2 includes a bottom wall 21 attached to the leg post 12, left and right side walls 22 rigidly connected to the bottom wall 21, a rear wall 23 connecting between rear ends of the side walls 22, A top wall (not shown) that connects the upper ends of the side walls 22 is provided. A long hole 221 capable of holding a front shaft j1 for supporting the front portion of the seat 3 movably back and forth is formed at the front end of the side wall 22. The back support 4 is rotatably supported at the intermediate portion in the front-rear direction of the side walls 22 via a support shaft j2.

<Za 3>
The seat 3 includes a seat 31 and a seat body 32 provided on the seat 31 so that the front and rear positions can be changed. The lower surface of the seat 31 includes both ends of a front shaft j1. A front bearing 311 for holding and a rear bearing 312 for holding both ends of a rear shaft j3 described later are provided.

<Spine support 4>
The back support 4 includes left and right arms 41 whose intermediate portion is pivotally supported by the support base 2 via a support shaft j2, and a coupling member 42 for rigidly connecting the rear portions of the left and right arms 41. It is. The coupling member 42 includes a rear plate 421 provided at the rear end of the left and right arms 41, an intermediate plate 422 provided at a portion of the left and right arms 41 closer to the center in the front-rear direction, and the intermediate plate 422 and the rear plate. 421, and a channel member 423 disposed between the inner surfaces of the arms 41. The rear plate 421, the channel member 423, and the intermediate plate 422 are integrally formed of a sheet metal material. It is configured.

  The rear plate 421 is a single one, and is provided with a plurality of bolt insertion holes h1 for inserting a plurality of bolts v1, and a nut portion n1 is provided on the lower surface side of each of the bolt insertion holes h1. I have. That is, the backrest mounting portion t for mounting the backrest 5 is mainly composed of the rear plate 421 and the nut portion n1.

  In addition, between the channel member 423 and the rear wall 23 of the support base 2, a rearward tilt locking mechanism 6 for locking the backrest 5 at a desired rearward tilting position is provided. The rearward tilt lock mechanism 6 includes a plurality of lock holes 231 provided at intervals in the rear wall 23 in the vertical direction, and a protrusion that is disposed in the channel member 423 and engages with one of the lock holes 231. The lock plate includes a lock plate (not shown) that can be protruded and retracted between a position and a disengagement position where the lock plate is disengaged from the lock hole 423, and an operation lever 61 that protrudes and retracts the lock plate.

  The rear shaft j3 is penetrated in a portion of the left and right arms 41 corresponding to the channel member 423, and both ends of the rear shaft j3 projecting outward from the arm 41 are provided with the seats. The rear bearing 312 of the receiver 31 is engaged. A receiving shaft 43 is provided between the front ends of the left and right arms 41, and the backrest 5 is rotated forward between the receiving shaft 43 and the front end of the support base 2 via the back support 4. A reaction force mechanism 7 for biasing is provided. Here, reference numeral 71 denotes a coil spring constituting the reaction force mechanism 7, and reference numeral 72 denotes a preload adjusting lever for adjusting the preload of the coil spring 71.

<Backrest 5>
The backrest 5 includes a back frame 51 attached to the backrest mounting portion t, a tension member 52 stretched on the back frame 51, and a back frame 51 positioned on the back side of the tension member 52. And a lumbar support 53 attached thereto. The backrest 5 has a backrest surface configured to receive the back of the occupant from behind by a mesh-shaped tension member 52.

  The back frame 51 has left and right side frame members W1 having outwardly opened tension member mounting grooves m1 and upwardly opened tension member mounting grooves m2 and connects upper portions of the left and right side frame members W1. The upper frame member W2, the lower frame member W3 connecting the lower portions of the side frame members W1 to each other, the lower frame member W1 having a tension member mounting groove m3 opened downward, and the lower frame member W1 W3 and an intermediate connection frame member W4 for connecting the left and right side frame members W1 to each other with cavities s1 and s2 formed therebetween, and these side frame members W1, upper frame member W2, and lower frame member W2. The frame member W3 and the intermediate connecting frame member W4 are integrally formed of a synthetic resin.

  The back frame 51 includes an upper frame-like portion f1 in which an upper cavity s1 is formed by the left and right side frame members W1, the upper frame member W2, and the intermediate connection frame member W4, and the left and right side frame members W1 and the lower frame. A lower frame-shaped portion f2 in which a lower cavity s2 is formed inside by the material W3 and the intermediate connecting frame material W4.

  The lower portions of the left and right side frame members W1, that is, the lower portions W1d of the left and right side frame members W1 constituting the lower frame portion f2 have a shape that is close to each other downward as viewed from the front.

  The upper portions W1u of the left and right side frame members W1 constituting the upper frame portion f1 have a U-shape projecting forward in a side view. The portion of the upper portion W1u that protrudes most forward is set at a position corresponding to the waist portion of the seated person. Further, lower portions W1d of the left and right side frame members W1 constituting the lower frame portion f2 have a U-shape projecting rearward in a side view.

  On the outer side surfaces of the left and right side frame members W1, a tension member mounting groove m1 is formed from the upper end of the side frame member W1 to a height position substantially corresponding to the lower edge of the intermediate connecting frame member W4. Further, on the front surface of the left and right side frame members W1, a step portion z extending inward from near the lower end portion of the tension member mounting groove m1 is formed. The step portion z is formed on the front portion of the side frame member W1 at a height position substantially corresponding to the lower edge of the intermediate connecting frame member W4, and is formed of a step in which the lower side comes forward before the upper side. The step z of the step portion z substantially corresponds to the thickness of the tension member 52.

  The thickness of the upper portion W1u of the left and right side frame members W1 forming the upper frame portion f1 in the front-rear direction is the lower portion W1d of the left and right side frame members W1 forming the lower frame portion f2. Is set smaller than the thickness dimension in the front-rear direction.

  The left and right side frame members W1 include an outer frame portion w11, and an inner frame portion w12 located inside the outer frame portion w11 and having a front portion located behind the front portion of the outer frame portion w11. I have. The tension member mounting groove m1 and the step portion z are formed in the outer frame portion w11. A nut portion n2 for attaching an attachment member H of the lumbar support 53, which will be described later, and a concave portion k1 for positioning are provided at a vertically intermediate portion of the inner frame portion w12. In the lower part of the inner frame portion w12, a plurality of recessed spaces k2 are provided in a vertical direction via plate-shaped ribs r1, r2, r3, r4.

  More specifically, the inner frame portion w12 of the side frame member W1 has a rear wall w121 extending inward from the rear edge of the outer frame portion w11 and an inner wall w122 extending forward from the inner surface of the rear wall w121. And The nut portion n2 is provided between the outer frame portion w11 and the inner wall w122 of the inner frame portion w12 so as to form a pair up and down. The concave portion k1 is formed by a pair of the nut portion n2 and the outer frame. It is formed between the portion w11 and the inner wall w122.

  The lower part W1d of the left and right side frame members W1 is set to have a larger left-right width dimension and a front-rear width dimension than the upper part W1u. Plate-shaped ribs r1, r2, r3, r4 are provided at intervals in the vertical direction between the outer frame portion w11 and the inner wall w122 in the lower portion W1d, and these ribs r1, r2, r3, r4, the outer frame portion w11, the back wall w121, and the inner wall w122 form a plurality of recessed spaces k2 opened to the front side.

  The upper rib r4 is formed so as to be integrally continuous with the eave portion w42 of the intermediate connecting frame member W4. The rib r3 disposed under the rib r3 is provided at a height position corresponding to the position of the lower edge of the intermediate connecting frame member W4, and the front end of the rib r3 is located rearward as compared with the other ribs r1, r2, r4. It is in the form. That is, the front end of the rib r3 is formed so as to be continuous with the front surface of the intermediate connection frame material main body w41. The outer end of the rib r3 is continuous with the step portion z in a front view.

  The upper frame member W2 includes an outer frame portion w21 and an inner frame portion w22 which is located inside the outer frame portion w21 and whose front portion is located behind the front portion of the outer frame portion w21. In addition, a tension member mounting groove m2 that opens upward is formed continuously on the outer surface of the outer frame member w21. On the rear side of the tension member mounting groove m2, a groove mz for mounting the hanger 9 is provided. The groove mz is formed in a crescent shape projecting rearward in a plan view, and the front-back dimension of the bottom groove part mz1 in the groove mz is shorter than the front-rear opening dimension of the opening end part mz2 in the groove mz. No. A groove engaging portion 931 provided on the front end side of the first clamp member 93 engages with the groove mz. In the inner part w22 of the upper frame member W2, a pair of guide projections w221 is provided on the front side on the left and right sides. Since the second clamp member 94 of the hanger 9 described later can be engaged with a predetermined inner frame portion w22 along the protrusion w221, the hanger 9 is attached to the chair body B at a suitable position. You can do it.

  The lower frame member W3 is a flat lower frame member body w31 superimposed on the backrest mounting portion t of the back support member 4, and extends downward from both side edges of the lower frame member body w31. And left and right side walls w32 disposed on the outer surface side of the arm 41, and a rear wall w33 extending downward from the rear edge of the lower frame material main body w31 and disposed on the rear end side of the back support 4. The lower frame material main body w31, both side walls w32, and the rear wall w33 are respectively integrally connected to the side frame material W1. A bolt insertion hole h2 corresponding to the nut portion n1 of the back support 4 is formed in the lower frame member main body W31, and the bolt v1 inserted through each of the bolt insertion holes h2 is provided with the nut portion n1 of the back support 4. The back frame 51 is attached to the back support 4 by screwing the back frame 51 onto the back support 4.

  A cover 54 for hiding the head of the bolt v1 is mounted on the lower frame member W3. On the lower surface of the cover 54, a front elastic claw 541 and a rear elastic claw 542 project downward, and the front elastic claw 541 is engaged with the front edge of the lower frame member body w31 and the rear elastic claw 542 is provided. Is engaged with an engagement hole an provided in the lower frame member main body w31, whereby the cover 54 is fixed on the lower frame member main body w31. The cover 54 has a shape that covers the lower frame member W3 from the upper side and covers two left and right concave spaces k2 formed at the lower end of the side frame member W1.

  The intermediate connecting frame member W4 is provided between the left and right side frame members W1 and between the portions inclined forward when viewed from the side, and has a curved shape projecting rearward in plan view. The thickness dimension in the front-rear direction of the intermediate connection frame member W4 is set smaller than the thickness dimension in the front-rear direction of the left and right side frame members W1 at the same height position as the intermediate connection frame member W4.

  More specifically, the intermediate connecting frame member W4 includes an intermediate connecting frame member body w41 provided between the left and right side frame members W1, and an eave portion w42 protruding from the front surface of the intermediate connecting frame member body w41. And a plurality of hanging parts w43 hanging downward from the lower surface of the eave portion w42 along the front surface of the intermediate connecting frame material body w41. The back surface of each hanging part w43 and the intermediate connecting frame material A tension member mounting groove m3 that opens downward is formed between the front surface of the main body w41 and the front surface. These tension member mounting grooves m3 are formed intermittently with a gap left and right.

  The intermediate connection frame member main body w41 is set so that the front surface thereof is substantially continuous with the front surface of the side frame member W1, and has a rear surface substantially parallel to the rear surface of the side frame member W1 and a cross section having a substantially horizontal bottom surface. It has a substantially triangular shape. The front surface of the intermediate connection frame member body w41 is inclined forward like the front surface of the side frame member W1, and the tension member mounting groove m3 formed between this front surface and each of the hanging portions 43 is located below. It opens toward the cavity s1. That is, the tension member mounting groove m3 formed in the intermediate connection frame member W4 is opened downward in a state of being inclined obliquely and rearward.

  In the vicinity of a portion where the left and right side frame members W1 and the intermediate connection frame member W4 are connected, a tension member mounting groove m4 at an end opening downward is provided. In this embodiment, both right and left ends of the intermediate connection frame material body w41 are provided with both end hanging portions w44 that hang downward from the eaves w42, and these both end hanging portions w44 and the intermediate connection frame material body w41 are provided. A tension member mounting groove m4 at the end is also formed between the front surface and the front surface. The tension member mounting grooves m4 at these ends also open toward the lower cavity s1.

  The upholstery member 52 is formed by fastening a belt-like member G to the periphery of a mesh-like cloth J capable of forming a backrest surface by sewing or the like. By engaging with m2, m3, and m4, it is stretched on the front surface of the upper frame portion f1 of the back frame 51.

The band-shaped member G includes a side frame member engaging portion g1 that engages with the tension member mounting groove m1 of the left and right side frame members W1, and an upper frame member engaging portion that engages with the tension member mounting groove m2 of the upper frame member W2. g2, a tension member mounting groove m3 of the intermediate coupling frame material W4, and an intermediate coupling frame material engaging portion g3 that engages with the tension member mounting groove m4 at the end. The part g1 and the upper frame material engaging part g2 are provided integrally and continuously. The intermediate connecting frame member engaging portion g3 is separated from the side frame member engaging portion g1 near the end of the intermediate connecting frame member W4. For this reason, a region where the band-shaped member G does not exist is provided only in the portion arranged on the step portion z on the periphery of the mesh-shaped cloth J.

  The lumbar support 53 is disposed between the left and right side frame members W1 of the backrest 5 so as to be located behind the tension member 52. The lumbar support 53 is positioned inside the side frame members W1 and attached to these side frame members W1. The left and right mounting members H make a pair, and the lumbar support main body I is suspended between the left and right mounting members H so that the vertical position can be changed.

  The lumbar support main body I has a plate-shaped lumbar plate i1 in which the thickness dimension of the middle part in the vertical direction is set to be larger than the thickness dimensions of the upper part and the lower part. And a mounting member engaging portion i2 which is provided so as to protrude toward the mounting member and engages with the mounting member H.

  The lumbar support 53 has the left and right mounting members H mounted on the left and right side frame members W1 holding the mounting member engaging portion i2 of the lumbar support main body I so as to be slidable in the vertical direction. A detent mechanism S for stably holding the lumbar support main body I at a desired height position is provided between the main body I and the left and right mounting members H. In other words, the lumbar support main body I is configured to be able to engage with the mounting member H in the up-down direction.

  The mounting members H are arranged in pairs on the left and right, and as shown in FIG. 3, are set to have front and rear dimensions that can be hidden by the side frame member W1 in a side view. In other words, the thickness dimension in the front-rear direction of the portion of the side frame member W1 to which the attachment member H is fastened is the same as the thickness dimension of the attachment member H in the front-rear direction, or is greater than the thickness dimension of the attachment member H in the front-rear direction. Is also set large. The mounting member H includes a front member p that holds the front side of the lumbar support main body I, and a rear member q that holds the rear side of the lumbar support main body I. The rear member q is attached to the side frame member W1 using a bolt v2. The attachment member H is attached to the inner frame portion w12, and the front surface of the attachment member H is set to be substantially flush with the front surface of the outer frame portion w11. Further, the mounting member H has a bolt insertion hole h3 extending in the front-rear direction for fastening to the side frame member W1, and the tension member 52 stretched in front of the bolt insertion hole h3 allows It covers the bolt insertion hole h3 and the head of the bolt v2 inserted into the bolt insertion hole h3.

  The rear member q of the mounting member H has a bolt insertion hole h3 on the upper and lower sides and covers the front wall of the inner wall w122 of the side frame member W1 so as to cover the recess k1 of the side frame member W1. q1, a side wall q2 extending rearward from the inner edge of the front wall q1 and abutting on the inner surface of the inner wall w122 of the side frame member W1, and a rear wall q3 extending inward from the rear edge of the side wall q2. It is provided with.

  A bolt insertion hole h3 corresponding to the nut portion n2 of the side frame member W1 is formed at the upper and lower ends of the front wall q1, and a bolt v2 inserted through the bolt insertion hole h3 is connected to the nut of the side frame member W1. By screwing to the portion n2, the rear member q is fixed to the side frame member W1. The rear surface of the front wall q1 is provided with a vertically extending protruding portion q11 that sandwiches the inner wall w122 of the side frame member W1 in cooperation with the side wall q2.

  A hook portion q31 for attaching the front member p is provided at an upper end of the front surface of the rear wall q3, and a downward nut portion n3 is provided at a lower end. In the vicinity of the inner edge of the front surface of the rear wall q3, a rib-shaped holding portion q32 for holding the mounting member engaging portion i2 of the lumbar support body I in cooperation with the front member p is protruded.

  The front member p of the mounting member H is a curved strip which is attached to the rear member q by sliding its inner edge into contact with the front surface of the mounting member engaging portion i2 of the lumbar support main body I. On the rear surface of the front member p, an engaging claw p1 that engages with the claw hook q31 of the rear member q, and a protruding piece p2 having a bolt insertion hole h4 corresponding to the nut portion n3 are provided integrally. I have.

  The lumbar plate i1 of the lumbar support main body I has a curved shape such that the central portion protrudes rearward, and can support the back of the seated person via the tension member 52.

  The attachment member engaging portion i2 of the lumbar support main body I is a plate-shaped member integrally provided at both ends of the lumbar plate i1. On the back surface of the mounting member engaging portion i2, a positioning protruding portion i21 extending in the vertical direction and abutting on the inner surface of the holding portion q32 of the rear member q, and located outside the holding portion q32, A bulging portion i22 that is in contact with the rear wall q3 of the member q is provided.

  The moderation mechanism S includes a moderation recess k3 continuously provided at a predetermined pitch in the vertical direction on the inner surface of the holding portion q32 of the rear wall q3, and a bulging portion in the attachment member engaging portion i2 of the lumbar support main body I. and a moderation convex portion i23 provided on the inner side surface of the i22, and by moving the lumbar support main body I up and down with respect to the mounting member H, the moderation convex portion i23 becomes one of the moderation concave portions k3. To be selectively engaged with.

<Synchronous locking mechanism R>
The synchro-rocking mechanism R is for changing the angle of the seat 3 at a fixed ratio in accordance with the tilt of the backrest 5, and is provided at the front end of the support base 2 via a front shaft j1. Is supported so as to be movable back and forth, and the rear end of the seat 3 is pivotally supported by the arm 41 of the back support 4 via a rear shaft j3. Note that the rear shaft j3 is inserted through a portion of the arm 41 located behind the support shaft j2. In this embodiment, the rear shaft j3 is positioned inside the channel member 423. And is provided on the arm 41.

<Hanger 9>
The hanger 9 is for hanging clothes and the like, and is attached to an upper frame member W2 as a frame member constituting the chair body B.

  The hanger 9 includes a hanger body 91 extending in the left-right direction for hanging clothes and the like, a pair of left and right hanger legs 92 extending forward and downward from the lower surface of the hanger body 91, and one surface side of the upper frame material W2, that is, the upper surface side. A second clamping member engaged with the other surface side, that is, the lower surface side of the upper frame member W2 so as to clamp the upper frame member W2 in cooperation with the first clamp member 93. A clamp member 94, a nut N inserted inside the first clamp member 93, and a bolt v3 screwed to the nut N through a bolt insertion hole h6 provided in the second clamp member 94. Is provided.

  The hanger body 91 is curved so as to protrude rearward, and has both ends as free ends.

  The hanger legs 92 are provided at the intermediate position of the hanger main body 91 so as to be integrated left and right, and the first clamp member 93 is integrally provided at the lower end of each hanger leg 92.

  The first clamp member 93 has a nut insertion opening sn opened rearward for inserting the nut N therein. The first clamp member 93 includes a groove engaging portion 931 on the front side that engages with the groove z provided in the upper frame member W2. A bolt insertion hole h5 communicating with the nut insertion port sn is formed in the lower surface of the first clamp member 93.

  More specifically, the first clamp member 93 includes a top wall 93a in which the lower end of the hanger leg 92 is integrated, a front wall 93b extending obliquely forward and downward from the front edge of the top wall 93a, It has a wall 93b and a block 93c integrally formed on the lower surface side of the top wall 93a. The front wall 93b and the top wall 93a have the same lateral width, and the groove engaging portion 931 is formed at the front end of the front wall 93b. The block portion 93c has a smaller horizontal dimension than the front wall 93b and the top wall 93a, and the nut insertion opening sn is formed in the block portion 93c. A bolt insertion hole h5 communicating with the nut insertion port sn is formed on the lower surface of the block portion 93c.

  The second clamp member 94 includes a bottom wall 94a abutting on the lower surface of the upper frame member W2, and a side wall 94b extending upward from both left and right edges of the bottom wall 94a and externally fitting to the block portion 93c. It is provided. At the front end of the bottom wall 94a, a bent inner frame portion engaging portion 941 that is engaged with the inner frame portion w22 of the upper frame material W2 is formed, and at the rear end of the bottom wall 94a, the block portion 93c is formed. A concealing portion 942 is formed to be attached to the back surface of the nut to conceal the nut insertion opening sn.

  The outer surfaces of the side walls 94b are formed so as to be substantially flush with the top wall 93a of the first clamp member 93 and both side surfaces of the front wall 93b, and the outer surface of the bottom wall 94a is The top wall 93 a of one clamp member 93 and the back surface of the hanger leg 92 are flush with each other. A pedestal portion 943 is formed on the inner surface of the bottom wall 94a so as to be fitted to the lower end of the block portion 93c. The pedestal portion 943 corresponds to the bolt insertion hole h5 of the first clamp member 93. A bolt insertion hole h6 is provided.

  The procedure for attaching the hanger 9 to the back frame 51 is as follows.

  First, after inserting a nut (T nut) N from the rear into the nut insertion opening sn of the first clamp member 93, the groove engaging portion 931 of the first clamp member 93 is inserted into the groove z of the upper frame member W2. Engage from above. Then, the inner frame portion engaging portion 941 of the second clamp member 94 is engaged with the inner frame portion w22 of the upper frame member W2 from the lower side while using the protrusion w221 as a mark, and the second clamp member 94 is moved to the second position. It is externally fitted to the block portion 93c of one clamp member 93.

  In this state, the bolt v3 is inserted from below into the bolt insertion hole h6 of the second clamp member 94 and the bolt insertion hole h5 of the first clamp member 93, and the bolt v3 is screwed into the nut N. . Due to the tightening force of the bolt v3, the upper frame member W2 is nipped from above and below by the first clamp member 93 and the second clamp member 94, and the hanger 9 is attached to the upper frame member W2 of the back frame 51. Fixed.

  As described above, the chair A according to the present embodiment has the backrest 5 in which the tension member 52 is stretched on the back frame 51. The back frame 51 has left and right side frame members W1 having outwardly opened tension member mounting grooves m1, and upper portions of the left and right side frame members W1 having upwardly opened tension member mounting grooves m2. An upper frame member W2 connecting between the two, a lower frame member W3 connecting between the lower portions of the side frame members W1, and a cavity s2 between the lower frame member W3 having a tension member mounting groove m3 opened downward. And an intermediate connecting frame member W4 for connecting the left and right side frame members W1 to each other in a state in which is formed. For this reason, since the cavity s2 is formed below the intermediate connecting frame member W4, it becomes easy to form the downwardly extending tension member mounting groove m3 in the intermediate connecting frame member W4 even in the back frame 51 of an integrally molded product.

  The lower portions of the left and right side frame members W1 are shaped so as to approach each other downward when viewed from the front. For this reason, not only can a suitable external appearance be achieved, but also it is easy to secure the strength of the parts having the opposite shapes, and it is easy to design to improve the strength of the back frame 51.

  The intermediate connection frame member W4 is provided between portions of the left and right side frame members W1 that are inclined forward in a side view. For this reason, in order to form the tension member mounting groove m3 that opens downward in the intermediate connecting frame member W4, a structure in which the cavity s2 can be easily designed below the intermediate connecting frame member W4 can be adopted.

On the front side of the intermediate connection frame member W4, a plurality of the tension member mounting grooves m3 are provided at intervals in the left-right direction. Therefore, the lower edge of the tension member 52 can be favorably supported.

  Near the portion where the left and right side frame members W1 and the intermediate connecting frame member W4 are connected, a tension member mounting groove m4 at the end opening downward is provided. Therefore, the vicinity of the lower left and right edges of the tension member 52 can be supported by the tension member mounting groove m4 at the end disposed near the portion where the left and right side frame members W1 and the intermediate connection frame member W4 are connected. Thus, the tension member 52 is favorably supported so as to be distorted.

  The upper frame f1 in which the back frame 51 forms an upper cavity s1 by the left and right side frame members W1, the upper frame member W2, and the intermediate connection frame member W4, and the left and right side frame members W1 And the lower frame member f2 in which the lower cavity s2 is formed by the lower frame member W3 and the intermediate connection frame member W4. Therefore, it is possible to provide the back frame 51 which contributes to weight reduction and has excellent strength.

  The left and right side frame members W1 forming the upper frame portion f1 have a U-shape protruding forward in a side view, and the left and right side frame members forming the lower frame portion f2. W1 is in the shape of a letter protruding rearward in a side view. For this reason, the upper frame-shaped portion f1 has a suitable shape so as to wrap the back of the seated occupant from behind, and the lower frame-shaped portion f2 can take a shape suitably avoiding the seat 3 and the like. I have.

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

The back frame may be one in which the upper part of the intermediate connecting frame material is not hollow.

  The back frame is not necessarily limited to one integrally molded of synthetic resin, but may be, for example, one that mainly applies a metal such as aluminum, one that mainly applies wood, or one that mainly applies a clay material. You may.

  It goes without saying that the shape of the cavity, in other words, the shape of the upper frame portion f1 and the lower frame portion f2 can be changed as appropriate.

  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.

A: Chair 5: Backrest 51: Back frame m1, m2, m3, m4: Tension member mounting groove s1, s2: Hollow W1: (left and right) side frame material W2: Upper frame material W3: Lower frame material W4: Middle Connection frame material

Claims (7)

A chair having a backrest in which a tension member is stretched on a back frame,
The back frame has left and right side frame members having a tension member mounting groove opened outward, and an upper frame member having a tension member mounting groove opened upward and connecting upper portions of the left and right side frame members. And a lower frame member connecting the lower portions of the side frame members, and a left and right side frame member in a state where a cavity is formed between the lower frame member and a tension member mounting groove opened downward. A chair which is an integrally molded product having an intermediate connecting frame material to be connected. 2. The chair according to claim 1, wherein lower portions of the left and right side frame members have a shape that is converging downward in a front view. 3. The chair according to claim 1, wherein the intermediate connection frame member is provided between portions of the left and right side frame members that are inclined forward in a side view. 4. 4. The chair according to claim 1, wherein a plurality of the tension member mounting grooves are provided on the front side of the intermediate connecting frame member at intervals in the left-right direction. 5. The tension member mounting groove at an end opening downward is provided near a portion where the left and right side frame members and the intermediate connection frame member are connected to each other. Chair. The back frame, an upper frame-shaped portion in which an upper cavity is formed by the left and right side frame members, the upper frame member, and the intermediate connection frame member, the left and right side frame members, the lower frame member, The chair according to claim 1, 2, 3, 4, or 5, further comprising a lower frame-shaped portion in which the lower cavity is formed by an intermediate connecting frame material. The left and right side frame members constituting the upper frame-shaped portion are shaped like a letter protruding forward in a side view, and the left and right side frame members constituting the lower frame portion are side-viewed. 7. The chair according to claim 6, wherein the chair has a U shape protruding rearward.

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