JP2018057640A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair equipped with a back shell in the shape of shell that can give a sitter a sense of security.SOLUTION: A chair is provided with a back shell formed into a shell-shape composing a backrest. The back shell is provided with a back shell body having a waist support part for supporting the waist part of a sitter and a projection which extends forward from both sides of the waist support part of the back shell body. The projection is in the shape whose vertical width becomes gradually smaller forward. As such, the chair is provided with the shell-shaped back shell that can give the sitter a sense of security.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, various chairs having a backrest are known (see, for example, Patent Document 1).

  By the way, in this type of chair, there is a chair whose backrest is mainly composed of a shell-like member. However, most of the conventional shell-like members have a flat plate shape arranged only on the back side of the seated person as a whole.

  The backrest composed of such a flat shell-like member does not give a sense of support for a lateral change in posture of the seated person, and a separate armrest. There are many cases where this is dealt with by arranging.

JP 2010-252892 A

  The present invention has been made paying attention to the above situation, and an object thereof is to provide a chair provided with a shell-like back shell that can give a suitable feeling of support to a seated person.

  That is, the present invention has the following configuration.

  The invention according to claim 1 is a chair provided with a shell-like back shell that constitutes a backrest, wherein the back shell has a waist support portion for supporting a waist portion of a seated person. A shell main body and a protrusion that extends forward from both sides of the waist support portion of the back shell main body are provided, and the protrusion has a shape in which the vertical width gradually decreases toward the front. It is a chair.

  According to a second aspect of the present invention, there is provided a chair provided with a shell-like back shell constituting a backrest, wherein the back shell has a waist support portion for supporting a waist portion of a seated person. A shell body and a protrusion extending from the both sides of the waist support portion of the back shell body to the front side, the protrusion being a rear side corresponding to a boundary with the back shell body; It has a substantially triangular shape in a side view and includes an upper side described forward from the upper end of the rear side, and a front side extending from the front end of the upper side to the lower end of the rear side, from the front side. Also, the rear side is set to a short dimension, and the upper side is set to be shorter than the rear side.

  Invention of Claim 3 is a chair of Claim 2 with which the front edge of the front side part in the said protrusion part is following the lower edge of the said back shell main body smoothly.

  The invention according to claim 4 is the chair according to claim 1, 2, or 3, wherein the protrusion is a frame having a cavity in the intermediate region.

  The invention according to claim 5 is the chair according to claim 1, 2, 3 or 4, wherein the protrusion is an armrest.

  A sixth aspect of the present invention is the chair according to the first, second, third, fourth or fifth aspect, wherein the backrest can operate in a manner different from a seat.

  As described above, according to the present invention, it is possible to provide a chair having a shell-like back shell that can give a suitable feeling of support to a seated person.

The perspective view which shows one Embodiment of this invention. The front view in the embodiment. The rear view in the embodiment. The right view in the same embodiment. The top view in the embodiment. The bottom view in the embodiment. XX sectional drawing (lower part) in FIG. XX sectional drawing (upper part) in FIG. The exploded perspective view in the embodiment. The exploded perspective view in the embodiment. The exploded perspective view in the embodiment. The perspective view in the embodiment. The rear view in the embodiment. The YY sectional view taken on the line in FIG. ZZ 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. Sectional drawing of the state which the backrest in the same embodiment decomposed | disassembled. The perspective view in the embodiment. FIG. 20 is a cross-sectional view corresponding to FIG. 14 in the state shown in FIG. 19. Sectional drawing for demonstrating the back inclination movement restriction | limiting mechanism in the embodiment. The rear view for demonstrating that a common back cover can be applied to the backrest of a different type.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In this embodiment, a back cushion is disposed on the front side of the back support member M, but the illustration is omitted.

  In this embodiment, the present invention is applied to an office swivel chair A (hereinafter simply referred to as “chair A”) having a so-called weight sensing type locking function.

  The chair A is supported by a leg 1, a support base 2 supported by the leg 1, a seat 3 disposed on the support base 2, and a back frame 4 supported by the support base 2 via a back frame 4. The backrest I is provided.

  The leg body 1 is provided with a leg base 1a formed by radially arranging a plurality of leg blades 11 each having a caster 12 at the tip, and a leg column 1b made of a gas spring standing on the leg base 1a. is there.

  The support base 2 is mainly composed of a top wall 2a having a flat plate shape, a side wall 2b having a flat plate shape suspended from the left and right side edges of the top wall 2a, and a bottom wall 2c constructed between the lower ends of both side walls 2b. It is configured. A cover 2d for concealment made of synthetic resin is provided outside the support base 2.

  The top wall 2a has an intermediate opening 21 in which the upper end of the leg strut 1b can be exposed at an intermediate portion corresponding to the leg strut 1b, and a rear end opening 22 in which a reaction force spring B is disposed at the rear end. It is the flat thing provided with. On the top surface of the top wall 2a, a receiving surface m that constitutes a later-described tilting motion restriction mechanism D is provided.

  The side wall 2b is provided with a long hole 24 that is inclined in a direction of gradually retreating upward in the vicinity of the front end. In the long hole 24 of the side wall 2b, a front shaft j1 for supporting the front portion of the seat 3 is slidably held along the long hole 24. An operation shaft 25 for adjusting the seat height is rotatably held in the vicinity of the middle portion in the front-rear direction corresponding to the leg support 1b on the side wall 2b.

  That is, the side wall 2b has an operation shaft 25 extending in the left-right direction, an arm 26 provided at one end of the operation shaft 25 and serving as a release operation portion for directly releasing the telescopic lock of the leg column 1b, and the operation shaft 25. An operation lever 27 is provided at the other end for direct rotation operation by the user, and a seat height operation portion that engages with the leg support 1b is configured by these. Between the intermediate part corresponding to the leg support 1b on the side wall 2b and the rear end part corresponding to the reaction force spring B, it extends in the left-right direction for pivotally supporting the base end part of the back frame 4 so that it can be tilted backward. The main shaft sj is penetrated.

  The bottom wall 2c is constructed between the lower ends of the side walls 2b and includes a boss portion 28 to which the upper ends of the leg columns 1b are attached. A lower spring attachment portion 29 as a spring attachment portion for attaching a lower end portion of a reaction force spring B described later is provided at a rear end portion of the bottom wall 2c, that is, a portion corresponding to the rear end opening portion 22 of the top wall 2a. ing. In other words, the support base 2 is a reaction force spring B that urges the back frame 4 to rotate forward at a rear end that is a portion positioned behind the main shaft sj that rotatably supports the back frame 4. A lower spring mounting portion 29 is provided.

  Note that the position of the receiving surface m constituting the rearward tilting motion restriction mechanism D is set to the upper surface portion on the rear side of the upper surface portion corresponding to the main axis sj in the top wall 2a.

  The seat 3 includes a seat shell 3a integrally having a seat receiving member 31 on the upper surface and a cushion 3b mounted on the seat shell 3a.

  The seat shell 3a has a configuration called an outer shell, and includes a front shaft holding portion 32 for receiving the front shaft j1 on the lower surface on the front side, and receives the rear shaft j2 on the lower surface on the rear side. For this purpose, a rear shaft holding portion 33 is provided. The seat receiving member 31 is a plate-like member for receiving the upper load of the seat 3. The seat receiving member 31 has a plurality of claws t1 for stopping the cushion 3b at its peripheral edge.

  The cushion 3b is obtained by mounting an exterior material 35 on a cushion main body 34 mainly made of foam. The cushion 3b is attached on the seat shell 3a by engaging the peripheral portion of the exterior member 35 with a claw t1 provided on the seat receiving member 31.

  The back frame 4 has a back support arm 4a disposed at the lower portion and an upper end mounting portion 4b disposed at the upper portion. The back frame 4 includes a left and right pair of back support arms 4a disposed on both sides of the support base 2, and an upper end mounting portion 4b provided at the upper end of the back support arm 4a. The back frame 4 is pivotally supported by the support base 2 via a main shaft sj installed on the base end of the back support arm 4a. A concealing cover 4c made of synthetic resin is provided outside the back frame 4.

  The back support arm 4a includes an extended portion 41 that extends obliquely forward and upward from the base end portion thereof. A rear shaft j2 is installed between the extending portions 41. The back support arm 4a is provided with a horizontal member 42 having an upper spring attachment portion 43 serving as a spring attachment portion for supporting the upper end portion of the reaction force spring B at an intermediate portion thereof. Between the horizontal member 42 and the support base 2, a backward tilt operation restriction mechanism D is provided.

  The upper end attachment portion 4b is attached between the back support arms 4a. The upper end mounting portion 4b includes an engagement protrusion t2 protruding upward from the upper edge, a locking window t3 drilled in the middle portion, and a plurality of female screw holes n1 provided in the upper and lower portions. It is. The upper end mounting portion 4b includes a pair of left and right side plates 44 continuous with the upper end of the back support arm 4a, an upper mounting plate 45 installed between the side plates 44, and a lower edge of the upper mounting plate 45 between the back support arm 4a. And a lower mounting plate 46 that is extended.

  On the upper edge of the upper mounting plate 45, an engagement protrusion t2 is provided in a manner protruding upward. The upper female screw holes n <b> 1 are formed at two upper left and right positions of the upper mounting plate 45. At an intermediate position of the upper mounting plate 45, a locking window t3 having a rectangular shape is provided.

  The lower mounting plate 46 is rigidly connected to the back support arm 4a by welding or the like. The lower female screw holes n1 are formed at two locations on the left and right sides of the lower mounting plate 46.

  Thus, the chair A shown in the present embodiment has a rearward tilt restricting state in which most of the rearward tilting operation can be restricted and a rearward tilting unrestricted state in which a predetermined range of backward tilting operations can be permitted by the action of the backward tilting motion restriction mechanism D. The state can be selectively taken.

  The rearward tilting action limiting mechanism D can limit the backrest I and the relative rotation of the seat 3 with respect to the support base 2 by limiting the rearward tilting action of the back frame 4 with respect to the support base 2. ing.

  The rearward tilting motion restriction mechanism D is supported by a rotating member E having a contact surface at at a rotating end and rotatably supported via a drive shaft c1 that is pivoted on the back frame 4, and corresponding to the contact surface at of the rotating member E. The receiving surface m provided on the base 2 and the rear tilt restricting posture (F) in which the contact surface at can come into contact with the receiving surface m when the back frame 4 tries to tilt backward, and the contact surface at comes into contact with the receiving surface m. And an operation unit C having a drive shaft c1 for switching between the non-reclined posture (G). In this embodiment, the receiving surface m is constituted by the upper surface of the top wall 2 a in the support base 2.

  The rotating member E has a contact surface at and has a rotating member main body e1 rotatably supported with respect to the back frame 4 via the drive shaft c1, and is integrally provided with the rotating member main body e1 and engages with the back frame 4. And a rotation stopper e2 that can regulate the rotation range of the rotating member main body e1.

  In this embodiment, the rotating member E has a single contact surface at. That is, in this embodiment, the contact surface at is set only on one surface side of the rotating member E so that it can hit the receiving surface m only when the rotating member E adopts the backward tilt restricting posture (F). The drive shaft c1 constituting the operation unit C is provided so as to penetrate between the left and right back support arms 4a. That is, the rotating member E is located between the left and right back support arms 4a. The rotating member E can be rotated integrally with the drive shaft c1 and is externally fitted so as to be movable in the axial direction.

  More specifically, the rotating member main body e1 has a plate shape as a whole having a contact surface at. The rotating member main body e1 protrudes from the outer periphery of the boss portion e11, and a boss portion e11 that can rotate integrally with the driving shaft c1 and can be fitted in the axial direction of the driving shaft c1. The projection plate e12 is provided with a plurality of ribs e13 formed on both surfaces of the projection plate e12 and having the base ends integrated with the boss portion e11. In addition, the contact surface at is provided in the front-end | tip part which is a rotation end of the protrusion board e12, and the front-end | tip part which is a rotation end of the rib e13.

  The rotation stopper e2 is extended from one end of the boss e11 in a direction substantially orthogonal to the protruding plate e12, and from the rotating end of the extension e21 to the drive shaft c1. And an engaging protrusion e22 protruding outward so as to be parallel. The rotation stopper e2 selectively makes the engagement protrusion e22 contact either one of the front contact portion u1 and the rear contact portion u2 which are two contact portions set on the lower edge of the back support arm 4a. Thus, the rotation range of the rotating member main body e1 is restricted to a certain range.

  In other words, in the backward tilt movement restriction mechanism D, the rotating member E can take the backward tilt non-restricted posture (G) in a state where the engagement protrusion e22 is in contact with the front contact portion u1, and the engagement protrusion e22 is rearward. The rotating member E is configured so as to be able to adopt the backward tilt restricting posture (F) in a state where it is in contact with the contact portion u2. Note that the rotating member main body e1 in the rearward tilt restricting posture (F) has a posture extending in a direction substantially orthogonal to the receiving surface m. In other words, the protruding direction of the protruding plate e12 in the backward tilt restricting posture (F) is set to be substantially orthogonal to the receiving surface m.

  In this embodiment, the backward tilt movement restriction mechanism D is provided with a moderation mechanism H for stably holding the rotating member E in the backward tilt unrestricted posture (G) or the backward tilt restricted posture (F). ing.

  The moderation mechanism H stops the rotation member E at a plurality of rotational positions. In other words, the moderation mechanism H is for stopping moderation in either the backward tilt unrestricted posture (G) or the backward tilt limited posture (F) corresponding to a plurality of rotational positions. The moderation mechanism H includes a coil spring sp that is provided between one back support arm 4a and the rotation member E and urges the rotation member E toward the other back support arm 4a, and the other back support. The engaging part h1 provided between the arm 4a and the rotating member E is provided.

  In other words, the moderation mechanism H is provided between one end surface of the rotating member E and the inner surface of the back support arm 4a facing the one end surface, and can engage with each other at a predetermined rotational position. The joint portion h1 and a coil spring sp that urges the rotating member E in a direction in which the engaging portion h1 can be engaged are provided.

  The engaging part h1 is provided on the inner surface of the back support arm 4a and the convex part h12 provided at the tip of the protruding piece h11 extending along the rotating member main body e1 from one end of the boss part e11 of the rotating member E. The two recessed parts h13 provided are provided. The convex part h12 can be selectively engaged with one of the two concave parts h13.

  The coil spring sp is interposed between the boss part e11 of the rotating member E and the inner side surface of one back support arm 4a. The coil spring sp is provided in a state of being wound around the drive shaft c1 of the operation unit C. The boss portion e11 is formed with a recessed portion e14 that can accommodate a part of the coil spring sp. Since the boss portion e11 is provided with the recessed portion e14, not only the coil spring sp having a constant length is stably disposed, but also between the rotating member E and the back support arm 4a. The gap that can be formed can be made as small as possible.

  One end of the drive shaft c1 protrudes outward from the outer surface of the back support arm 4a, and an operation lever c2 for operating the rotating member E to be rotatable is provided at the protruding end. That is, when the operation lever c2 is rotated by the user's hand, the rotating member E is freely rotated from the rearward tilt restricting posture (F) to the rearward tilt unrestricted posture (G) via the drive shaft c1. It becomes possible. At that time, since the entire rotating member E is pushed in the direction of the back support arm 4a on one side by the urging force of the coil spring sp, a convex portion h12 provided integrally with the rotating member E is provided on the back support arm 4a. The moderation operation is performed by smoothly engaging / disengaging with any of the plurality of recessed portions h13.

  The backrest I is attached to the back frame 4 described above.

  The backrest I can be tilted backward in a manner different from that of the seat 3. That is, when the back frame 4 supporting the backrest I performs a backward tilting operation, the rear shaft j2 supported by the back frame 4 moves rearward while ascending, and the rear end side of the seat 3 is inclined rearward and upward. While pushing up, the front shaft j1 supporting the front end side of the seat 3 is guided by the long hole 24 of the support base 2 and moves rearward and upward. As a result, when the backrest I supported by the back frame 4 performs a backward tilting operation, the seat 3 moves upward while moving upward. In other words, the chair A shown in this embodiment includes a weight-sensing locking mechanism configured so that the seat 3 can rise rearward and upward as the backrest I moves backward.

  The backrest I includes a back shell J attached to the upper end mounting portion 4b of the back frame 4, a back support member M for holding a back cushion (not shown) attached only on the front side of the back shell J, and a back shell J And a back cover N mounted on the back side. In other words, the backrest I has a triple structure formed by the back cover N, the lower support portion 5 of the back shell body K, and the back support member M.

  The back shell J includes a back shell main body K having a lower support portion 5 as a waist support portion for supporting a lower portion from the waist of the seated person, and a lower support portion 5 provided integrally with the back shell main body K. The armrest P which is a protrusion part extended from the side part to the front side is provided. The back shell main body K and the armrest P that is the protruding portion are integrally formed of a common material. In other words, the back shell J includes a back shell main body K positioned behind the seated occupant and armrests P as projecting portions positioned on the left and right of the seated occupant extending from both sides of the back shell main body K to the front side. The back shell body K and the armrest P are integrally formed of synthetic resin.

  The back shell main body K mainly includes a lower support portion 5 for supporting the lower portion of the seated person from the back and an upper support portion 6 for supporting the upper portion of the seated person from the back. It has. In this embodiment, the lower support portion 5 of the back shell body K constitutes an intermediate layer in the above-described triple structure.

  The lower support portion 5 includes a plurality of ribs on the back surface. The lower support portion 5 is provided at a position lower than the height position of the elbow rest surface p21 in the armrest P. The plurality of ribs provided on the lower support portion 5 include a vertical rib 5b and a horizontal rib 5c. In other words, the lower support portion 5 exposes a rib for ensuring strength toward the rear side. The lower support portion 5 includes a front wall 5a that forms the front surface of the back shell body K, a plurality of ribs including a longitudinal rib 5b and a lateral rib 5c provided on the back surface of the front wall 5a, and a longitudinal orientation. And a rear wall 5d having a window 52 that allows a plurality of ribs including the rib 5b and the lateral rib 5c to be exposed to the outside. A back cover N can be fitted into the window 52 of the back wall 5. The upper opening edge extending in the left-right direction in the window 52, that is, the upper edge extending in the left-right direction in the back cover N forms a straight line. The back shell J is configured such that the elbow rest surface P of the armrest P is positioned on a virtual extension line obtained by virtually extending the straight line that is the upper edge of the back cover N in the same direction. In this embodiment, a front frame 5a, longitudinal ribs 5b and lateral ribs 5c, which are part of the ribs, and a back frame attachment portion that is opened rearward and downward, mainly on the lower edge portion of the rear wall 5d. Q is formed.

  The back frame attaching portion Q is engaged with the engaging hole 53 into which the engaging protrusion t2 provided in the upper end attaching portion 4b of the back frame 4 is inserted and the edge of the engaging window t3 provided in the upper end attaching portion 4b. A fitting flange 54, a screw insertion hole 55 corresponding to the female screw hole n1 provided in the upper end attachment portion 4b, and an opening 56 connected in the vertical direction through which the upper end attachment portion 4b of the back frame 4 can be inserted. It is.

  More specifically, the back frame mounting portion Q includes a front wall 5a with the rear surface exposed rearward, and a pair of vertical ribs spaced apart in the left-right direction in the middle region in the left-right direction of the front wall 5a. 5b, a horizontal rib 5c installed between the upper portions of the vertical ribs 5b, and a lower edge portion of the back wall 5d connecting the lower ends of the vertical ribs 5b. . An opening 56 for inserting the upper end mounting portion 4b of the back frame 4 is formed between the front wall 5a and the lower edge portion of the back wall 5d in the lower support portion 5. That is, the opening 56 is formed at the center in the left-right direction at the lower end of the back shell body K. Further, a rectangular opening opened rearward is formed by the leading edge of the longitudinal rib 5b, the leading edge of the lateral rib 5c, and the upper edge of the lower edge portion of the back wall 5d.

  The locking hole 53 has a slit-like insertion opening formed in a laterally-oriented rib 5 c arranged on the upper portion of the lower support portion 5. The engagement protrusion t2 of the back frame 4 inserted into the locking hole 53 can be viewed from the front side of the back shell body K. The collar part 54 is a collar-like thing protruding downward so that the front-end | tip part may be located below a base end part. The flange 54 is located below the locking hole 53 and protrudes from the rear side of the front wall 5a. The screw insertion hole 55 is formed in the upper part and the lower part of the front wall 5a.

  The attachment of the back shell J to the back frame 4 is performed as follows, for example. First, the upper end mounting portion 4 b of the back frame 4 is inserted into the opening 56 of the back shell J. Next, the lower edge of the locking window t <b> 3 in the back frame 4 is hooked on the flange portion 54 of the back shell J while the engagement protrusion t <b> 2 of the back frame 4 is engaged with the locking hole 53 of the back shell J. As a result, the female screw hole n1 of the back frame 4 and the screw insertion hole 55 of the back shell J coincide with each other. Subsequently, the screw v1 is fixed to the female screw hole n1 through the screw insertion hole 55. The back shell J is attached to the back frame 4 through the above process.

  The upper support portion 6 includes a vertical rib 6b on the front surface. In other words, the upper support portion 6 exposes a plurality of vertical ribs 6b arranged in the left-right direction on the front side. The upper support portion 6 has a rear wall 6a that forms the rear surface of the back shell main body K, a plurality of vertical ribs 6b provided on the front surface of the rear wall 6a, and an upward hook shape for attaching the back support member M. And an attachment claw 6c formed.

  The back shell body K includes a boundary wall k for connecting the upper edge of the front wall 5a in the lower support part 5 and the lower edge of the back wall 6a in the upper support part 6 at an intermediate position in the vertical direction. . The boundary wall k is formed such that both ends in the left-right direction protrude forward from the center in plan view, and has a curved shape as a whole. The upper surface of the boundary wall k is connected to the lower ends of the plurality of vertical ribs 6 b formed on the front side of the upper support portion 6.

  The armrest P, which is a protrusion, is provided to extend from the side edge of the lower support portion 5 of the back shell body K to the front side. The armrest P has a shape in which the vertical width gradually decreases toward the front. The armrest P has a triangular frame shape having a cavity kd in the intermediate region.

  The armrest P includes a rear side part p1 integrally adjacent to the back shell body K, an upper side part p2 described forward from the upper end of the rear side part p1, and a front end of the upper side part p2 to a lower end of the rear side part p1. And a front side portion p3. The armrest P has a substantially triangular shape in a side view. The rear side portion p1, the upper side portion p2, and the front side portion p3 are each formed in a bar shape, and the rear side portion p1 is integrated with the back shell body K.

  The rear side portion p1 is provided on the front side of the back shell main body K, and includes an outer side surface p12 that is flush with the outer side surface p22 of the upper side portion p2 and the outer side surface p32 of the front side portion p3.

  Each of the upper side portion p2 and the front side portion p3 has a flat bar shape. On the upper surface of the upper side portion p2, an elbow rest surface p21 having a substantially horizontal flat shape is formed. The upper side portion p2 includes an elbow contact surface p21 that is an upper surface, and an outer surface p22 and an inner surface p23 that face in a direction substantially orthogonal to the elbow contact surface p21.

  The front side portion p3 includes a forward-facing surface p31 that faces the front side. The front side portion p3 includes an outer surface p32 that is substantially flush with the outer side surface p22 of the upper side portion p2, and an inner side surface p33 that is substantially flush with the inner side surface p23 of the upper side portion p2.

  In the armrest P, the dimension w1 of the rear side part p1 is set shorter than the dimension w3 of the front side part p3, and the dimension w2 of the upper side part p2 is set shorter than the dimension w1 of the rear side part p1. . The front edge of the front side portion p3 in the armrest P is smoothly continuous with the lower edge of the back shell main body K, that is, the lower edge of the back wall 5d. Further, the outer side surfaces of the front side portion p3 and the rear side portion p1 of the armrest P are continuous with the back surface of the back wall 5d.

  The back support member M is attached to the front surface of the back shell body K, and is set to have more flexibility than the back shell body K. The back support member M is integrally formed with a back support member main body 7 that is set to be thinner than the back shell main body K, and a reinforcing rib r that is provided on the back surface of the back support member main body 7 and has a relatively low degree of protrusion. It is provided. In this embodiment, the lower part of the back support member M corresponding to the lower support part 5 of the back shell body K constitutes the front layer in the above-described triple structure.

  The back support member main body 7 includes a downward mounting window 71 that engages with a mounting claw 6 c provided on the upper support portion 6 of the back shell main body K at an upper portion corresponding to the upper support portion 6 of the back shell main body K. Yes. The back support member main body 7 has an elastic engagement portion that can elastically engage with a mounting protrusion t4 provided on the lower support portion 5 of the back shell main body K at a lower portion corresponding to the lower support portion 5 of the back shell main body K. 72. The back support member main body 7 is provided with a locking claw 73 for attaching a back cushion for locking a peripheral portion of an exterior material in a back cushion (not shown) in the vicinity of the peripheral portion.

  The back cover N is attached to the back surface of the lower support portion 5. The back cover N has a form that can be attached to the window 52 in a state of being substantially flush with the outer surface of the back wall 5d of the back shell body K. That is, the back cover N is provided with a back frame mounting portion Q, and can be concealed so that the back side of the lower support portion 5 exposed to the outside has a suitable appearance. In this embodiment, the back cover N constitutes the rear layer in the triple structure described above.

  Specifically, the back cover N includes a locking protrusion N1 protruding from the lower edge, an elastic claw N2 protruding toward the back shell J in the vicinity of the upper edge, and an upper end. A nut portion N3 is provided near the left and right end portions in the vicinity, and a screw (not shown) that passes through a screw insertion hole t5 provided in the back shell J is screwed into the nut portion N3. The back cover N has the locking protrusion N1 inserted into a slit-shaped or recessed locking portion 57 provided near the lower edge of the window 52 in the back shell main body K, and the elastic claw N2 is inserted into the back shell main body N2. An elastic claw engaging portion 58 provided on the upper portion of the lower support portion 5 at K is elastically engaged and a screw (not shown) is screwed onto the nut portion N3 to be attached to the back shell body K. . Note that a communication hole 59 for releasing the engagement between the elastic claw N2 and the elastic claw engagement portion 58 is provided at a portion corresponding to the elastic claw engagement portion 58 in the front wall 5a of the back shell J. Is formed.

  In addition, as shown in FIG. 23, the chair A of this embodiment is configured so that a plurality of types can be attached as the backrest I with different vertical dimensions of the back shell main body K. What is shown in FIGS. 1 to 4 is a so-called low-back type, and is shown in the center of FIG. The right side in FIG. 23 is referred to as a so-called high back type in which the vertical dimension of the back shell body K (and the vertical dimension of the back support member M corresponding thereto) is longer than that of the low back type. Is. What is shown on the left side in FIG. 23 is a so-called mini-back type in which the vertical dimension of the back shell main body K (and the vertical dimension of the back support member M corresponding thereto) is shorter than that of the low-back type. It is what is done. The back shell main body K of the mini back type is configured mainly with the lower support portion 5, and the size of the back support member M is also formed corresponding to the size of the back shell main body K of the mini back type. The back cover N shown in this embodiment is configured so that it can be commonly attached to any type of the back shell J described above. In other words, the size of the window 52 to which the back cover N provided on the lower support portion 5 of the back shell body K can be attached is set in common in any type of back shell J.

  Next, the operation of the chair A related to the backward tilt movement restriction mechanism D in this embodiment will be described.

  In a state where no back load is applied to the backrest I, the backrest I is caused by the biasing force of the reaction force spring B and the biasing force due to the weight of the seated person acting on the seat 3. The rear shaft j2 is biased forward, and is held at an initial position where it abuts against a stopper 23 provided on the upper surface of the top wall 2a of the support base 2.

  As shown in FIG. 7 and the like, when the rotation member E is in a backward tilting non-restricted posture (G) that cannot contact the support base 2 as shown in FIG. When the pressing force is applied, the backrest I can tilt backward together with the back frame 4. If the backward pressing force against the backrest I is eliminated, the backrest I will self-return to the initial position.

  On the other hand, when the rotation member E is in the back tilt restricting posture (F) capable of coming into contact with the support base 2 as shown in FIGS. On the other hand, even if a rearward pressing force is applied, the contact surface at of the rotating member E comes into contact with the receiving surface m of the support base 2 and is restricted so that the back frame 4 can hardly be tilted backward along with the backrest I. .

  The rotating member E is stably held by the moderation mechanism H in the backward tilt unrestricted posture (G) and the backward tilt restricted posture (F). The moderation mechanism H can give the user a clear click feeling that can indicate the completion of the operation by the operation unit C, and thus can contribute to a good and light switching operation.

  As described above, the chair A according to the present embodiment includes the back shell J that forms the shell shape that constitutes the backrest I. The back shell J has a lower shell portion K having a lower support portion 5 as a waist support portion for supporting a seated person's waist portion, and extends from both sides of the lower support portion 5 of the back shell body K to the front side. The armrest P, which is a projecting portion, has a shape in which the vertical width gradually decreases toward the front. For this reason, the chair A provided with the back shell J which makes the shell shape which can give a suitable feeling of support to a seated person can be provided.

  In other words, since the back shell J has the armrests P extending from the both sides of the lower support portion 5 of the back shell body K to the front side, the seated person has a certain level of security for changing the posture in the left-right direction. It is something that can be given. In other words, since the back shell J has the armrests P that extend forward from both sides of the lower support portion 5 of the back shell body K, the back shell J as a whole surrounds the seated person. Therefore, it is possible to give a visual and structural impression that the seated person is not likely to fall even if the posture is changed.

  In addition, since the armrest P has a shape in which the vertical width gradually decreases toward the front, the armrest P is excellent in design flexibility so as not to interfere with the flow line of the seated person.

  Furthermore, since the back shell J is formed by integrally forming the back shell body K and the armrest P, it not only improves the convenience of the seated person, but also has a high degree of freedom in design to improve the strength. It has become.

  The armrest P, which is a protrusion, includes a rear side part p1 corresponding to the boundary with the back shell body K, an upper side part p2 extending forward from the upper end of the rear side part p1, and a rear side part p1 from the front end of the upper side part p2. It has a substantially triangular shape in a side view with a front side portion p3 reaching the lower end. The dimension w3 of the rear side part p2 is set shorter than the dimension w3 of the front side part p3, and the dimension w2 of the upper side part p2 is set shorter than the dimension w1 of the rear side part p1. For this reason, it has a suitable shape that hardly interferes with the flow line at the time of sitting or working by the seated person.

  The front edge of the front side portion p3 in the armrest P is smoothly continuous with the lower edge of the back shell body K. For this reason, not only can the appearance of the rear portion of the seat 3 and the periphery of the back frame 4 that easily give a relatively complicated impression be made clear, but also the side edge and the lower edge of the back shell J can be formed. It becomes difficult to form a shape that is easily caught, and it is possible to suitably suppress the catch of an article or the like.

  The armrest P has a frame shape having a cavity kd in the intermediate region. For this reason, the armrest P is excellent in air permeability, its rigidity is easily secured structurally, and can function suitably as a handle portion when the user moves the chair A. Yes.

  The backrest I can operate in a manner different from the seat 3. In other words, the backrest I and the seat 3 are configured not to operate integrally during the backward tilting operation or the returning operation. For this reason, the design freedom for providing a comfortable sitting comfort for the seated person is excellent.

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

  The protrusion of the back shell is not limited to the armrest. That is, the protruding portion that integrally protrudes from the back shell body is not limited to one that can function as an armrest. For example, as a protrusion part, the handle part which protruded from the back shell main body so that it may be located in the side part of a seated person may be comprised.

  The configurations of the support base and the back frame are not limited to those shown in the above-described embodiments, and various configurations may be adopted.

  For example, the back shell may be configured integrally with the back frame.

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

I ... Backrest J ... Back shell K ... Back shell body P ... Armrest (protrusion)
kd ... hollow p1 ... rear side p2 ... upper side p3 ... front side 5 ... lower support part

Claims (6)

A chair with a back shell that forms a backrest,
The back shell is integrally provided with a back shell body having a waist support portion for supporting a waist portion of a seated person, and protrusions extending from both sides of the waist support portion of the back shell body to the front side. And
The chair in which the protruding portion has a shape in which the vertical width gradually decreases toward the front. A chair with a back shell that forms a backrest,
The back shell is integrally provided with a back shell body having a waist support portion for supporting a waist portion of a seated person, and protrusions extending from both sides of the waist support portion of the back shell body to the front side. And
The protruding portion is a rear side corresponding to the boundary with the back shell body, an upper side described forward from the upper end of the rear side, and a front side extending from the front end of the upper side to the lower end of the rear side. And has a substantially triangular shape when viewed from the side,
The chair in which the rear side portion is set to be shorter than the front side portion, and the upper side portion is set to be shorter than the rear side portion. The chair according to claim 2, wherein a front edge of a front side portion of the protruding portion is smoothly continuous with a lower edge of the back shell body. The chair according to claim 1, 2, or 3, wherein the protruding portion is a frame-shaped member having a cavity in an intermediate region. The chair according to claim 1, 2, 3, or 4, wherein the protrusion is an armrest. The chair according to claim 1, 2, 3, 4 or 5, wherein the backrest can operate in a manner different from a seat.

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