JP7575905B2 - chair - Google Patents

Description

The present invention relates to a chair suitable for use in offices, etc.

Chairs whose backrest surface is made of a mesh-like upholstery member have been known for some time (see, for example, Patent Document 1). The chair disclosed in Patent Document 1 is configured so that the lower part of the upholstery member can protrude forward by pressing the upholstery member from the rear toward the front with a lower backrest frame disposed behind the upholstery member.

In addition, there are various types of chair backrests of this type that have a mesh-like upholstery stretched around the periphery of a frame-shaped backrest.

However, the tension of the upholstery material attached to the back frame tends to make it flat. This makes it difficult to improve the design of the upholstery material located at the bottom of the back frame in conventional chairs.

JP 2002-119367 A

The present invention was made with the above in mind, and aims to provide a chair that can maintain the lower part of the upholstery member stretched over the backrest in a suitable shape.

That is, the present invention has the following configuration.

The invention described in claim 1 is a chair having a backrest with an upholstery member stretched on a back support member having a frame-shaped portion, the back support member having a upholstery member mounting portion extending in the left-right direction and to which the lower end of the upholstery member is attached, and a upholstery member pushing portion is provided which can push the lower part of the upholstery member further rearward than the upholstery member mounting portion , the back support member comprising a back frame main body having left and right side frames in which mounting grooves are formed to which the side ends of the upholstery member are attached, a lower frame connecting the lower ends of the left and right side frames, and an upper frame in which a mounting groove is formed to which the upper end of the upholstery member is attached and connecting the upper ends of the left and right side frames, and a cover body in which a mounting groove which is the upholstery member mounting portion is formed and which covers the rear side of the lower frame .

The invention described in claim 2 is a chair having a backrest with an upholstery member stretched on a back support member having a frame-shaped portion, wherein the back support member is provided with a upholstery member attachment portion extending in the left-right direction and to which the lower end of the upholstery member is attached, and a upholstery member push-out portion is provided which can push the lower part of the upholstery member further rearward than the upholstery member attachment portion, the upholstery member push-out portion is plate-shaped and has a rearward extending portion and a curved extending portion which is continuous with the rearward extending portion and curves gradually upward toward the rear, and the lower surface of the rearward extending portion and the back surface of the curved extending portion can abut against the front surface of the upholstery member .

The invention described in claim 3 is a chair described in claim 1 or 2, in which the lower part of the upholstery member wraps around to cover the rear side of the upholstery member extrusion portion and the lower end part of the upholstery member is attached to a part of the back support member.

The invention described in claim 4 is the chair described in claim 1 , wherein the upholstery member extrusion portion is provided integrally with the lower frame.

The invention described in claim 5 is the chair described in claims 1, 2, 3, or 4, in which the upholstery member pushing portion is shaped to protrude rearward from the upholstery member mounting portion and has a curved surface that can come into contact with the front surface of the upholstery member.

The invention described in claim 6 is a chair as described in claim 1 or 4, comprising legs, a support base attached to the upper ends of the legs, a support supported so as to be rotatable in the front-to-back direction relative to the support base, a seat whose front portion is rotatably supported relative to the support base and whose rear portion is rotatably supported relative to the support, and a backrest supported by the support, wherein the back frame main body is provided with a support connection portion including the lower frame and connected to the support .

The invention described in claim 7 is a chair as described in claim 6, in which the support connection portion comprises left and right side connection portions which form a pair on the left and right and extend in the front-to-back direction, and a lower frame which connects the rear end portions of the left and right side connection portions, and which is configured so that each inner portion of the left and right side connection portions can be connected to an outer portion of the support, and so that the front portion of the lower frame can be connected to the rear portion of the support .

The invention described in claim 8 is a chair described in claim 1, 4, 6 or 7, wherein the cover body is attached to the back side or the underside of the lower frame by a fastener .

The invention described in claim 9 is a chair having a backrest with an upholstery member stretched on a back support member having a frame-shaped portion, wherein the back support member is provided with a upholstery member mounting portion extending in the left-right direction and to which the lower end of the upholstery member is attached, and a upholstery member pushing portion is provided which can push the lower part of the upholstery member further rearward than the upholstery member mounting portion, and the back support member is provided with a back frame main body having left and right side frames in which mounting grooves are formed to which the side ends of the upholstery member are attached, a lower frame in which mounting grooves are formed and which connects the lower ends of the left and right side frames, which is the upholstery member mounting portion to which the lower end of the upholstery member is attached, and an upper frame in which mounting grooves are formed and which connects the upper ends of the left and right side frames, and an extrusion member provided with the upholstery member pushing portion and attached to a support body capable of supporting the lower frame or the back frame main body .

As described above, the present invention provides a chair that can maintain at least the lower part of the upholstery member stretched over the backrest in a suitable shape.

FIG. 1 is a perspective view showing an embodiment of the present invention. 4 is a right side view of the same embodiment. FIG. FIG. FIG. FIG. FIG. Cross-sectional view taken along line XX in FIG. FIG. FIG.

One embodiment of the present invention will be described below with reference to Figures 1 to 9.

In this embodiment, the present invention is applied to a swivel chair (hereafter simply referred to as "chair") suitable for use in an office or similar setting.

The chair comprises legs A, a support base B attached to the upper ends of the legs A, a support C supported so as to be rotatable in the front-to-rear direction relative to the support base B, a seat D whose front portion is rotatably supported relative to the support base B and whose rear portion is rotatably supported relative to the support C, a backrest E supported by the support C, and armrests F supported by the support C.

The leg A has multiple leg blades a1 arranged radially, each having a caster a11 at its tip, and a leg support a2 erected at the base end of the leg blade a1.

The support base B is supported by the leg A and is configured to be rotatable. The support base B includes a support base main body 1 fixed to the upper end of the leg support a2, and a link member 2 rotatably supported on the front end of the support base main body 1 via a rear link shaft j3.

The support base body 1 is box-shaped and contains a reaction spring (not shown) that can urge the backrest E in the normal position. The upper end of the leg support a2 is connected to the rear of the support base body 1. The support base body 1 is provided with a main shaft j1 for rotatably supporting the support body C. A pair of main shaft support parts 11 protrude upward from the rear of the support base body 1, one on the left and one on the right, and capable of supporting both ends of the main shaft j1 extending in the left-right direction.

The link member 2 is configured to be rotatable relative to the support base body 1. The link member 2 is supported rotatably relative to the support base body 1 between a normal position in which it extends in a direction that is approximately aligned with the longitudinal direction of the support base body 1 in a side view, and an upright position (not shown) in which the front end portion of the link member 2 moves upward from the normal position in conjunction with the backward tilting movement of the backrest E and the seat D.

The base end of the link member 2 is pivotally attached to the support base body 1, and the tip end is pivotally attached to the seat frame S. The front end of the link member 2 is connected to the seat D via the front link shaft j2, and the rear end of the link member 2 is connected to the support base body 1 via the rear link shaft j3.

The support C can cooperate with the support base B to support the seat D. The support C is interposed between the support base B and the backrest E, and between the support base B and the armrest F. In other words, the support C can support the backrest E and the seat D. The support C is provided with backrest mounting parts k1, L1 to which the backrest E can be attached, and an armrest mounting part 32 to which the armrest F can be attached. The support C is set so that in the normal position, it is generally tilted forward relative to the horizontal.

The support body C is equipped with a rear bridge frame J extending in the left-right direction, left and right side frames K extending rearward from both the left and right sides of the rear bridge frame J, and a rear frame L connecting the rear ends of the left and right side frames K.

In this embodiment, the rear bridge frame J, the left and right side frames K, and the rear frame L are integrally formed from metal. The support body C is supported at the rear of the support base B via the main shaft j1 so as to be rotatable in the front-rear direction. The support body C can support the seat frame S arranged on the support body C so as to be rotatable in the front-rear direction.

The rear bridge frame J is disposed under the seat D. The rear bridge frame J is equipped with a rear bridge frame main body 3 that is curved so as to form a downward convexity when viewed from the front, and a main shaft holding portion 4 that protrudes downward from the center in the left-right direction of the rear bridge frame main body 3 and can hold the main shaft j1 supported by the support base B.

The rear bridge frame body 3 is designed to rotatably support the seat frame S via seat support shafts j4 at both left and right ends. The rear bridge frame body 3 is provided with shaft holders 31 that protrude upward from both left and right sides, and each shaft holder 31 holds a seat support shaft j4 that pivots on the seat D.

At both ends of the rear bridge frame body 3, recessed armrest mounting sections 32 are provided to which armrests F can be attached.

The left and right side frames K extend rearward in a substantially straight line from the rear bridge frame main body 3. The left and right side frames K are provided with backrest attachment parts k1 on the left and right outer sides to which the backrest E is attached.

The backrest attachment portion k1 provided on the left and right side frames K has a positioning protrusion k11 that is an engagement portion that is fitted into the backrest E, and a screw insertion hole h2 that penetrates in the left-right direction and through which a screw v2 that is screwed into the backrest E is inserted. The positioning protrusion k11 of the backrest attachment portion k1 protrudes outward from the vertical middle of the outer portion of the left and right side frames K.

The rear frame L is bridged between the rear ends of the left and right side frames K. The rear frame L has an overall curved shape that is convex toward the rear. The rear frame L is provided with a backrest attachment portion L1 at the rear side, i.e., the rear portion, to which the backrest E is attached.

The backrest attachment portion L1 provided on the rear frame L has a positioning protrusion L11 as an engagement portion that is fitted into the backrest E, and a screw insertion hole h3 that penetrates in the front-rear direction and through which a screw v3 that screws into a nut portion n3 provided on the lower frame i2 is inserted. The positioning protrusion L11 of the rear frame L protrudes rearward from the vertical middle portion of the outer portion of the rear frame L.

The seat D is equipped with a seat frame S, which is composed of a continuous ring-shaped frame-like member, and a seat body P, which has a seating surface and is attached to the seat frame S.

The seat frame S is comprised of a frame-shaped seat frame body M and a front bridge frame T that is provided in a bridge shape connecting both the left and right ends of the seat frame body M. The seat frame body M and the front bridge frame T are integrally formed from synthetic resin.

The left and right seat frame parts m1 of the seat frame main body M have seat support shaft holders m11 that protrude downward from the inner edge of the rear part and can hold the seat support shaft j4. In other words, the seat support shaft j4 is held by the seat support shaft holder m11 provided on the seat frame S and the shaft holder 31 provided on the support body C, allowing the seat frame S to rotate in the front-rear direction relative to the support body C.

The front bridge frame T extends in the left-right direction and is capable of supporting the seat frame body M from below. The front bridge frame T is supported at the front of the support base B so that it can rotate in the front-rear direction relative to the support base B.

The front bridge frame T is equipped with a front bridge frame main body 5 having a curved portion that is curved to form a downward convex shape when viewed from the front and rear, and a front axle holding part 6 that protrudes downward from the center of the front bridge frame main body 5 in the left-right direction and can hold the front link axle j2 that is attached to the support base B.

The seat body P comprises a seat intermediate frame body (not shown) that is placed on the seat frame body M, a seat cushion (not shown) that is placed on the seat intermediate frame body, and seat upholstery p3, which is an exterior material that covers the upper and side surfaces of the seat intermediate frame body and the seat cushion.

In addition, the seat may be a mesh type seat that uses a mesh-like upholstery material instead of a cushion type seat. In other words, the seat body may be equipped with a seat frame body having a rectangular seat frame on which a mesh-like upholstery material is stretched.

The backrest E is made up of a back support member G, which has a rectangular frame-shaped portion mainly composed of left and right side frames i1, a lower frame i2, an upper frame i3, and a cover body Q, and a mesh-like tension member H is stretched over the back support member G. The backrest E is supported by the support body C so that it can rotate in the front-rear direction relative to the support base B.

The back support member G is made up of a back frame body I that is integrally molded from synthetic resin and includes left and right side frames i1, a bottom frame i2, an top frame i3, and left and right side connection parts i4, and a cover body Q that is separate from the back frame body I and covers the rear side of the bottom frame i2 of the back frame body I.

The back frame body I is equipped with left and right side frames i1 that extend in the vertical direction and have mounting grooves mz formed on their outer edges to which the side ends of the tensioning member H are attached, a lower frame i2 that extends in the horizontal direction and connects the lower ends of the left and right side frames i1 to each other and connects to the rear of the support body C, an upper frame i3 that extends in the horizontal direction and has mounting grooves mz formed on its upper edges to which the upper ends of the tensioning member H are attached and connects the upper ends of the left and right side frames i1 to each other, left and right side connection parts i4 that extend forward from the lower ends of the left and right side frames i1 and connect to the left and right side frames K of the support body C, and a tensioning member pushing part U that is provided at the top of the lower frame i2 and can press the lower part of the tensioning member H backward.

In this embodiment, the left and right side frames i1, the lower frame i2, the upper frame i3, the left and right side connection parts i4, and the upholstery member extrusion part U that constitute the back frame body I are integrally formed from synthetic resin.

The back frame body I is made up of the left and right side connection parts i4 and the bottom frame i2, and is roughly U-shaped when viewed from above and from the bottom, forming the support connection part R that is connected to the support C.

The left and right side frames i1 are paired and extend vertically. The left and right side frames i1 have a bent portion i11 that protrudes furthest forward at the portion corresponding to the waist of the seated person. The left and right side frames i1 are V-shaped in side view.

A step i12 is provided on the front side of the upper part of the left and right side frames i1, which is recessed more at the bottom than at the top. A band-shaped cushioning member (not shown) extending in the vertical direction is attached to the front surface between the lower recessed portion i13 formed by the step i12 and the vicinity of the lower end of the left and right side frames i1. The cushioning member attached to the left and right side frames i1 is designed to reduce the load on the tension member H when the peripheral portion of the top plate of a desk or table collides with the backrest E. In other words, the cushioning member is designed to reduce the impact so that the tension member H is not strongly compressed between the left and right side frames i1 and the top plate.

By attaching the cushioning material to the recessed portion i13, the stepped portion i12 becomes substantially flush, and the upholstery material H located on the surface side is prevented from having unevenness. Therefore, even if the body of a seated person comes into contact with the stepped portion i12, the seated person does not feel uncomfortable due to the presence of unevenness.

The lower frame i2 is adapted to have its front portion attached to the backrest attachment portion L1 of the rear frame L of the support body C. The lower frame i2 is provided with a recessed portion i21 in the vertical middle portion into which the positioning protrusion L11 formed on the rear frame L of the support body C can be fitted, a nut portion n3 into which the screw v3 that passed through the screw insertion hole h3 of the rear frame L of the support body C is screwed, and screw insertion holes h5 provided in three locations at the center and on the left and right, through which the screw v5 for attaching the cover body Q to the rear side of the lower frame i2 is inserted.

As will be described in detail later, a tension member pushing portion U is integrally provided on the upper portion of the lower frame i2, which can push the lower portion of the tension member H rearward beyond the mounting groove mz of the cover body Q, which is the tension member mounting portion.

The upper frame i3 has a curved shape that convexly extends toward the rear.

The left and right side connection parts i4 are adapted to have their inner parts attached to the backrest attachment parts k1 of the left and right side frames K of the support body C. The left and right side connection parts i4 are provided with a recessed part i41 in the vertical middle part into which the positioning protrusions k11 formed on the left and right side frames K of the support body C can fit, a nut part (not shown) into which the screw v2 that passed through the screw insertion hole h2 of the left and right side frames K of the support body C is screwed, and a notch part i42 provided on the inner part of the underside into which the positioning fitting protrusion q21 provided on the cover body Q can fit.

In this embodiment, the chair is provided with an upholstery member pushing section U that can push the lower end of the upholstery member H, that is, the lower frame portion hm, backward in order to improve the appearance of the area near the lower edge of the upholstery member H.

The tension member extrusion portion U is integrally provided at the upper end of the lower frame i2. The lower frame i2 and the tension member extrusion portion U are integrally formed from synthetic resin. The tension member extrusion portion U is capable of extruding the lower portion of the tension member H, i.e., the lower frame portion hm, which is the portion positioned along the lower frame i2, toward the rear side beyond the mounting groove mz of the cover body Q, which is the tension member mounting portion.

The tension member push-out portion U has a shape that protrudes rearward from the mounting groove mz, which is the tension member mounting portion provided on the cover body Q. The tension member push-out portion U has a curved surface um that abuts against the front surface of the lower frame portion hm of the tension member H, and this curved surface um makes it possible to form the lower frame portion hm of the tension member H into a curved shape that convex toward the rear against the elastic restoring force of the tension member H.

More specifically, the tension member extrusion U is integral with the lower frame i2 and extends in the left-right direction along the lower frame i2. The tension member extrusion U has a width dimension that is slightly shorter than the distance between the lower parts of the left and right side frames i1. The tension member extrusion U is in the form of a plate that is cantilevered relative to the lower frame i2.

More specifically, the tension member extrusion portion U comprises a rearward extending portion u1 that extends rearward from the upper portion of the lower frame i2, a curved extending portion u2 that is continuous with the rearward extending portion u1 and curves so as to be positioned gradually upward toward the rear, and an upward extending portion u3 that extends upward from the curved extending portion u2 and curves so as to be positioned gradually forward toward the upper side, with its upper edge being a free end. The base end of the rearward extending portion u1 is integrated with the upper portion of the lower frame i2.

In this embodiment, the lower surface of the rearward extending portion u1, the back surface of the curved extending portion u2, and the back surface of the upward extending portion u3 come into contact with the front surface of the lower frame portion hm of the tension member H, forming a curved shape that is convex toward the rear on the lower frame portion hm of the tension member H.

In this embodiment, the back frame main body I is provided with a support connection part R that includes a lower frame i2 and is connected to the support C. The support connection part R is equipped with left and right side connection parts i4 that form a pair on the left and right and extend in the front-to-rear direction, and a lower frame i2 that connects the rear ends of the left and right side connection parts i4. The support connection part R is designed so that the inner parts of the left and right side connection parts i4 can fit into the outer parts of the side frames K of the support C, and the front part of the lower frame i2 can fit into the rear part of the rear frame L of the support C.

The support connection part R provided on the backrest E is guided by a rail-shaped positioning protrusion k11 extending in the front-rear direction provided on the side of the support C, and is attached while sliding so as to be inserted into the rear part of the support C. The support connection part R8 is U-shaped and can be fitted from the outside into the rear part of the support C, which is made up of the left and right side frames K and the rear frame L and has an overall convex shape in a plan view.

The cover body Q covers the rear side of the lower frame i2. The cover body Q is formed with a mounting groove mz that extends in the left-right direction and serves as a tension member mounting portion to which the lower end of the tension member H is attached. The cover body Q is attached to the rear side of the lower frame i2 with a screw v5 that serves as a fastener.

The cover body Q is made of synthetic resin. The cover body Q has a rear cover part q1 that covers the rear part of the lower frame i2, and a lower cover part q2 that extends forward from the lower end of the rear cover part q1 and covers the lower part of the lower frame i2.

The rear cover part q1 is an upright wall extending in the left-right direction as well as the up-down direction. A tension member attachment part, i.e., an attachment groove mz that is open forward, is formed on the front side of the upper part of the rear cover part q1, which extends in the left-right direction and to which the lower end of the tension member H is attached. Nut parts n5 are provided in three places on the center and left and right sides of the rear cover part q1, into which a screw v5 inserted into a screw insertion hole (not shown) provided in the lower frame i2 can be screwed.

The lower cover part q2 is a wall-like member that extends in the left-right direction and in the front-rear direction. The front end of the left-right center part of the lower cover part q2, i.e., the front end excluding the mating protrusion q21, is designed to be able to abut against the rear frame L of the support body C.

The lower cover part q2 has an engagement piece q21 at the front of both left and right ends, which fits into the notch i42 provided on the underside of the left and right side connection parts i4. The engagement piece q21 of the lower cover part q2 is roughly rectangular in bottom view. The engagement piece q21 on the lower cover part q2 fits into the notch i42 provided on the left and right side connection parts i4 of the back frame body I, thereby positioning the cover body Q at a predetermined position relative to the back frame body I.

The tension member H is stretched over the frame-shaped portion of the back support member G. The tension member H is mesh-like and supports the weight of a seated occupant. The tension member H is stretched over the frame-shaped back support member G by inserting and fixing the left and right side ends into the mounting grooves mz of the side frames i1, inserting and fixing the lower end into the mounting groove mz provided in the cover body Q, and inserting and fixing the upper end into the mounting groove mz of the upper frame i3. A band-shaped member made of synthetic resin (not shown) is sewn to the ends of the tension member H inserted into each mounting groove mz.

The lower part of the tension member H wraps around to cover the rear side of the tension member push-out part U, and the lower end of the tension member H is attached to the cover body Q, which is part of the back support member G.

In this embodiment, the tensioning member H is tensioned relative to the back support member G, for example, by the following procedure.

First, the tension member H is attached to the mounting groove mz provided in the back frame body I. That is, the left and right side ends of the tension member H are pushed into the mounting groove mz in the left and right side frames i1 and the top end of the tension member H is pushed into the mounting groove mz in the top frame i3.

Next, the lower end of the tension member H is pushed into the mounting groove mz provided in the cover body Q to attach it. At this time, the cover body Q is not attached to the lower frame i2 of the back frame main body I.

Then, the cover body Q with the lower end of the tension member H attached is attached to the rear of the lower frame i2. In this embodiment, the fitting protrusion q21 protruding from the lower cover part q2 of the cover body Q is fitted into the notch part i42 provided in the left and right side connection parts i4 of the back frame main body I to position it, and the screw v5 inserted into the screw insertion hole h5 provided in the lower frame i2 of the back frame main body I is screwed into the nut part n5 provided in the rear cover part q1 of the cover body Q, so that the cover body Q can be fixed to the lower frame i2.

The armrest F is a rectangular frame when viewed from the side, and includes an armrest body f1 with an upward-facing armrest f11 at its upper end, and an armrest arm f2 that extends downward from the front of the lower end of the armrest body f1.

The lower end, or base end f21, of the armrest arm f2 is connected to a recessed armrest mounting portion 32 provided on the rear bridge frame J.

As described above in detail, the chair according to this embodiment has a backrest E in which an upholstery member H is stretched over a back support member G having a frame-shaped portion.

The back support member G extends in the left-right direction and is provided with a mounting groove mz for the cover body Q, which serves as the tension member mounting portion to which the lower end of the tension member H is attached, and a tension member pushing-out portion U is provided that can push the lower portion of the tension member H, which is the lower frame-side portion hm, rearward beyond the mounting groove mz for the cover body Q, which serves as the tension member mounting portion.

For this reason, the chair according to this embodiment is able to maintain the lower portion hm of the upholstery member H that is stretched across the backrest E in a suitable shape.

In other words, the lower part of the upholstery member H is pushed rearward by the upholstery member pushing portion U beyond the mounting groove mz of the cover body Q, which serves as the upholstery member mounting portion, so that the shape of the lower part of the upholstery member H can be made to protrude rearward. Therefore, with this chair configuration, for example, by making the shape of the upholstery member H at the lower part of the backrest E when viewed from behind bulge rearward, it is possible to give the chair a desirable appearance with excellent design.

The back support member G is provided with a back frame body I having left and right side frames i1 with mounting grooves mz formed therein to which the side ends of the tension member H are attached, a lower frame i2 that connects the lower ends of the left and right side frames i1, and an upper frame i3 that connects the upper ends of the left and right side frames i1 with mounting grooves mz formed therein to which the upper ends of the tension member H are attached. The back support member G also has a cover body Q that covers the rear side of the lower frame i2 in the back frame body I, in which the mounting grooves mz that are the tension member attachment parts are formed.

For this reason, by providing a mounting groove mz, which is a tension member mounting portion, in the cover body Q that covers the rear side of the lower frame i2, excellent design freedom is provided for providing a tension member pushing portion U that can press the tension member H.

The tension member push-out portion U is integrally formed with the lower frame i2. This allows the tension member push-out portion U capable of pressing the tension member H to be provided in a manner with excellent strength.

The tension member push-out portion U is shaped to protrude rearward from the mounting groove mz of the cover body Q, which serves as the tension member mounting portion. The tension member push-out portion U has a curved surface um that can come into contact with the front surface of the tension member H.

As a result, the tension member extrusion section U is capable of deforming the lower portion of the tension member H into a suitable shape that has an excellent appearance.

The tension member extrusion portion U is plate-shaped and includes a rearward extending portion u1 that extends rearward, and a curved extending portion u2 that is continuous with the rearward extending portion u1 and curves so that it is positioned gradually upward toward the rear. The lower surface of the rearward extending portion u1 and the back surface of the curved extending portion u2 can abut against the front surface of the tension member H.

As a result, the tension member extrusion portion U can not only give the lower portion of the tension member H a suitable shape, but also can take a suitable shape that fits the tension member H itself.

It comprises legs A, a support base B attached to the upper end of the legs A, a support C supported so as to be rotatable in the front-rear direction relative to the support base B, a seat D whose front part is rotatably supported relative to the support base B and whose rear part is rotatably supported relative to the support C, and a backrest E supported by the support C. The back frame body I is provided with a support connection part R which includes a lower frame i2 and is connected to the support C.

For this reason, the backrest E is suitably supported by connecting the support connection part R to the support C.

The support body connection part R is equipped with left and right side connection parts i4 that form a pair on the left and right and extend in the front-to-rear direction, and a lower frame i2 that connects the rear ends of the left and right side connection parts i4. The inner parts of the left and right side connection parts i4 are configured so that they can be connected to the outer parts of the support body C, and the front part of the lower frame i2 can be connected to the rear part of the support body C.

As a result, the support connection portion R of the back panel body is suitably connected to the support C.

The cover body Q is attached to the rear side of the lower frame i2 by a fastener screw v5.

This makes it easy to attach the cover body Q to the back frame.

The present invention is not limited to the embodiments described above.

The structure of the backrest is not limited to the above-mentioned embodiment, as long as the tensioning member is stretched on the back support member having a frame-shaped portion. For example, the backrest may be mainly composed of a rectangular back frame having left and right side frames, a lower frame, and an upper frame on which the tensioning member is stretched, and the back frame may be supported on the support base via a back frame support rod or a back frame support frame. In this case, the lower frame may be a concept that includes a lower frame body that does not have a mounting groove for mounting the tensioning member and a cover body that has a mounting groove for mounting the tensioning member, or a concept that the main member is only the lower frame body that has a mounting groove for mounting the tensioning member.

The tension member pushing portion may be any portion capable of pushing the lower portion of the tension member rearward beyond the tension member mounting portion, and various specific configurations may be applied.

For example, the one shown in FIG. 9 is configured so that an extrusion member W having a tension member extrusion portion U is attached to a support C using a fastener screw v6.

That is, the back support member G of the backrest E shown in Figure 9 is equipped with a back frame body I having left and right side frames i1 with mounting grooves mz formed therein to which the side ends of the upholstery member H are attached, a lower frame i2 with mounting grooves mz formed therein that are upholstery member mounting parts to which the lower ends of the upholstery member H are attached and that connect the lower ends of the left and right side frames i1, and an upper frame i3 with mounting grooves mz formed therein to which the upper ends of the upholstery member H are attached and that connect the upper ends of the left and right side frames i1. It also has an extrusion member W with a upholstery member extrusion part U provided at the rear and a base end part w2 at the front attached to a support C capable of supporting the back frame body I.

The push-out member W has a base end w2 that is attached to the support C, and a tension member pushing-out part U that protrudes rearward from the upper part of the base end w2. A positioning protrusion w21 that protrudes rearward is provided at the lower end of the base end w2 of the push-out member W, and is adapted to engage with a forward-facing fitting groove i22 provided in the lower frame i2. A screw insertion hole h6 that penetrates vertically is provided in the base end w2, and the push-out member W is fixed to the support C by screwing a screw v6 inserted into the screw insertion hole h6 into a nut part (not shown) provided in the support C. Even with this configuration, the tension member pushing-out part U can push the lower frame-side part hm of the tension member H rearward, and the desired purpose can be achieved.

In the above-described configuration, the extrusion member W is attached to the support C by the screw v6, but it can of course also be configured to be attached to the lower frame.

The lower part of the tension member pushed out by the tension member pushing section is not limited to the part along the lower frame as in the above-mentioned embodiment.

The protruding portion of the extension member does not have to be a portion that presses the lower portion of the extension member into a curved shape.

The tension member attachment portion is not limited to an attachment groove into which the end of the tension member is pushed. The tension member attachment portion may be configured to attach the end of the tension member using, for example, a fastener.

The tension member pushing portion is not limited to being integral with the lower frame, but may be a separate piece attached with a fastener.

The tension member pushing portion is not limited to a curved plate shape, but may be, for example, a block shape with a curved surface on the back side that can come into contact with the tension member.

The support on which the backrest is supported may be of various shapes.

The specific configuration of each part is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

E: backrest G: back support member H: tension member mz: mounting groove (tension member mounting portion)
hm... Lower frame part (lower part of the upholstery member)
U: tension member extrusion section

Claims (9)

A chair having a backrest in which an upholstery member is stretched over a back support member having a frame-shaped portion,
The back support member is provided with a tension member attachment portion extending in the left-right direction and to which a lower end portion of the tension member is attached,
a tension member pushing portion that can push out a lower portion of the tension member toward the rear beyond the tension member mounting portion ;
The chair comprises a back frame main body, the back support member having left and right side frames each having an attachment groove into which the side ends of the upholstery member are attached, a lower frame connecting the lower ends of the left and right side frames, and an upper frame connecting the upper ends of the left and right side frames each having an attachment groove into which the upper end of the upholstery member is attached, and a cover body covering the rear side of the lower frame each having an attachment groove formed therein, which is the attachment portion for the upholstery member . A chair having a backrest in which an upholstery member is stretched over a back support member having a frame-shaped portion,
The back support member is provided with a tension member attachment portion extending in the left-right direction and to which a lower end portion of the tension member is attached,
a tension member pushing portion that can push out a lower portion of the tension member toward the rear beyond the tension member mounting portion ;
the tension member pushing portion is plate-shaped and includes a rearward extending portion and a curved extending portion that is continuous with the rearward extending portion and curves so as to be positioned gradually upward toward the rear,
A chair in which the underside of the rearward extension portion and the back surface of the curved extension portion can abut against the front surface of the upholstery member . 3. The chair according to claim 1, wherein a lower portion of the upholstery member wraps around to cover the rear side of the upholstery member extrusion portion, and a lower end portion of the upholstery member is attached to a part of the back support member. 2. The chair according to claim 1 , wherein the upholstery member extrusion is integrally formed with the lower frame. A chair according to claim 1, 2, 3 or 4, in which the upholstery member pushing portion is shaped to protrude rearward from the upholstery member mounting portion and has a curved surface that can abut against the front surface of the upholstery member. The chair comprises legs, a support base attached to the upper end of the legs, a support supported on the support base so as to be rotatable in the front-rear direction, a seat the front of which is rotatably supported on the support base and the rear of which is rotatably supported on the support, and the backrest supported on the support,
5. The chair according to claim 1, wherein the back frame body is provided with a support connecting portion including the lower frame and connected to the support. the support body connection portion includes left and right side connection portions that are paired left and right and extend in the front-rear direction, and the lower frame that connects rear ends of the left and right side connection portions,
7. The chair according to claim 6 , wherein the inner portions of the left and right side connection portions are configured to be connectable to the outer portions of the support and the front portion of the lower frame is configured to be connectable to the rear side portion of the support. The chair according to claim 1 , 4, 6 or 7 , wherein the cover body is attached to the back side or the underside of the lower frame by fasteners. A chair having a backrest in which an upholstery member is stretched over a back support member having a frame-shaped portion,
The back support member is provided with a tension member attachment portion extending in the left-right direction and to which a lower end portion of the tension member is attached,
a tension member pushing portion that can push out a lower portion of the tension member toward the rear beyond the tension member mounting portion;
The chair is provided with a back support member which comprises a back frame main body having left and right side frames in which mounting grooves are formed for attaching the side ends of the upholstery member, a lower frame which connects the lower ends of the left and right side frames and which is a mounting groove which is the upholstery member mounting portion for attaching the lower end of the upholstery member, and an upper frame which connects the upper ends of the left and right side frames and which is formed with a mounting groove for attaching the upper end of the upholstery member, and an extrusion member which is provided with the upholstery member extrusion portion and is attached to a support capable of supporting the lower frame or the back frame main body .

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