JP4896631B2 - Chair - Google Patents

Description

  The present invention relates to a chair whose backrest tilts backward by elastic deformation of a back frame device.

  As a chair with a relatively simple structure, there is a chair with a backrest attached to a frame device made of a bar material or a pipe material. In this type of chair, a rocking function in which the backrest tilts backward when the seated person leans down is performed. One example thereof is described in Patent Document 1.

  In other words, in Patent Document 1, the chair frame device includes a left and right lower horizontal portion that is placed on the floor, a left and right front foot portion that rises upward from the front end of the lower horizontal portion, and a rear end from the upper end of the left and right front foot portions. An upper horizontal portion that extends and left and right hind legs raised from a rear end of the lower horizontal portion are provided, and seats are attached to the upper and lower horizontal portions of the left and right.

  In addition, the rear ends of the left and right upper horizontal portions rise upward, and the left and right upper horizontal portions are integrally connected to each other at the lower horizontal portion, and the lower horizontal portions are connected to the lower back of the backrest. . Furthermore, the upper ends of the left and right hind legs are connected by upper horizontal portions, and the upper horizontal portions are connected to the back surface of the mid-height portion of the backrest. In the chair of Patent Document 1, the back tilt of the backrest is realized mainly by the rear foot tilting against the elasticity of the rear foot.

On the other hand, Patent Document 2 describes an example in which a seat and a backrest are supported by a frame in a rotary chair in which a leg column is constituted by a gas cylinder. Furthermore, the chair disclosed in Patent Document 3 has a shape in which the frame device is opened rearward in a side view, the lower end portion of the frame device is fixed to the base, and the backrest is attached to the upper rear portion of the frame device. .
Japanese Patent Publication No. 8-15446 Japanese National Patent Publication No. 9-502631 Japanese registered design No. 390617

  In order to improve the comfort in the locked state, it is effective that the backrest tilts backward as much as possible. Therefore, in the case of a chair that uses the elastic deformation of the frame device to lock the backrest, it is necessary to deform the frame device as much as possible. However, in the case of Patent Document 1, since the foot portion of the frame device is only elastically deformed thereafter, the amount of backward tilting of the backrest is small, and there is a limit to improving the comfort in the locked state. It was.

  Moreover, the chair of patent document 2 can only be said that a locking function cannot be expected so much because the seat and the backrest only slide back and forth as a whole. Moreover, it is estimated that the chair of patent document 3 cannot expect the high rocking function.

The present invention, Ru der has been made in view of such situation.

The chair of the present invention includes a seat supported by a base, a backrest that can be tilted backward, and a pair of left and right back frame devices fixed to the lower surface of the base or the seat, and the left and right back frames. The apparatus has a main portion that is disposed on the left and right outer sides of the seat and opens rearward in a side view, and an upper connecting portion to which the backrest is attached is provided at the upper rear end of the main portion. On the other hand, at the lower rear end of the main part in the back frame device, a lower connecting part that enters below the seat is integrally formed, and the lower connecting part has an end extending to the front side, and an end portion of the lower connecting portion is fixed to the base or the seat, further, the main portion of the back frame apparatus, generally sideways V-shape upper and lower interval is gradually increased toward the rear end from the front end in the structure that is formed on, the right and left The frame device is composed of a plurality of bar-shaped unit frames extending substantially in parallel, and the plurality of unit frames extend substantially in parallel in a plan view at least at the upper surface portion of the main portion. .

  The present invention includes variations described in claims 2 to 5. Of these, in the invention of claim 2, the front end portion of the main portion of the back frame device is curved in an arc shape in a side view.

In the invention of claim 3, in claim 1 or 2, attach the armrest to the two unit frames which constitute the upper surface portion of the front SL main unit.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the backrest includes a back inner shell having a cushion on the front surface and a back outer shell disposed on the back side of the back inner shell. On the other hand, at the upper rear end of the main portion in the back frame device, an upward inward portion that enters between the back inner shell and the back outer shell is integrally bent, and the upward inward The part is made up of the upper connecting part.

  According to a fifth aspect of the present invention, in the fourth aspect, the back outer shell is bent so that a rearward projecting portion for avoiding interference with the upper inward portion of the back frame device extends over the entire length of the left and right. ing.

  In the present invention, a. The main part of the back frame device has a shape opened rearward, so that the main part has a long overall length; b. A lower connecting portion constituting a lower portion of the back frame device is easily elastically deformed by receiving a twisting action and a bending action at the time of locking; c. The end portion of the lower connecting portion constituting the lower end portion of the back frame device is also easily deformed due to a twisting action and a bending action at the time of locking; d. Due to the fact that the lower connecting portion has a substantially forward end, the length of the main portion can be further increased, and the main portion is more easily deformed from this surface as well. have.

In the present invention, the above-described features a to d are entangled, so that the back frame device is easily deformed as a whole. For this reason, the backrest can be greatly tilted backward while being a simple chair of a frame system. As a result, the feeling of use in the locking state can be improved. In addition, since the plurality of unit frames extend substantially in parallel in a plan view at least at the location of the upper surface portion of the main portion, it is economical to use the back frame device for mounting the elbow rest as in claim 3. Is excellent. In the present invention, the left and right back frame devices are composed of a plurality of bar-shaped unit frames. Therefore, when locking, the unit frames regulate each other so that the backrest can be moved back with an appropriate reaction force. Since it can be tilted, it is possible to improve the leaning comfort when rocking.

  In order to increase the back tilt angle of the backrest, it is preferable that the amount of deformation of the back frame device is large. However, if the back frame device is deformed too much, the strength may decrease or the resistance to the body during rocking (anti-reverse) May be uncomfortable for the user. On the other hand, the present invention has excellent usability because it is suppressed from excessive deformation due to the main part of the back frame device being substantially V-shaped in a side view.

  The reason why excessive deformation is suppressed due to the main part of the back frame device being substantially V-shaped in a side view is that the length of the main part can be prevented from becoming too long, It is presumed that the moment can be distributed to each part of the main part. The configuration of claim 2 is particularly suitable because it can suppress stress concentration on the front end portion of the main portion of the back frame device.

When employing the configuration of the 請 Motomeko 4, upper inward portion of the back frame apparatus is excellent in appearance because hidden between the backrest of the back inner shell and the back outer shell. Adopting the configuration of claim 5 as a subordinate concept of claim 4 has the advantage that the backrest can be prevented from becoming thick as a whole, and the advantage that the strength of the back outer shell is increased by the rib effect of the rearward projecting portion. Therefore, it can be said that the invention of claim 5 is more preferable.

  Next, an embodiment of the present invention will be described with reference to the drawings.

(1). Outline of First Embodiment The chair of this embodiment is applied to a swivel chair. The chair includes a seat 1 and a backrest 2 that are integrally connected, legs 3 that support them, and left and right back frame devices 4 that hold the backrest 2 so as to be tiltable backward. The leg 3 is provided with a plurality of branch legs 3a extending in the radial direction in plan view and a leg column 5 made of a gas cylinder, and a caster 6 is provided at the tip of the branch leg 3a. A circular base 7 is fixed to the upper end of the leg column 5.

For example, as shown in FIG. 5 (A), the seat 1 includes a seat outer shell 8 made of plywood (wood board), a resin seat inner shell 9 fixed on the upper surface of the seat outer shell 8, and a seat inner shell. 9 and a seat cushion 10 stretched on the upper surface. On the other hand, the backrest 2 includes a back outer shell 11 made of plywood (wood board), a back inner shell 12 disposed on the front side thereof, and a back cushion 13 stretched on the front surface of the back inner shell 12. Needless to say , the cushions 10 and 13 are covered with a cloth (skin material). The back inner shell 12 can be made of either resin or metal, but it is preferable to use a metal (for example, a sheet metal or an aluminum die-cast product) when it is necessary to ensure strength.

  The seat inner shell 9 and the back inner shell 12 are formed with ribs 14 and 15 that overlap the outer shells 8 and 11. The seat outer shell 8 and the back outer shell 11, and the seat inner shell 9 and the back inner shell 12 are manufactured as separate members. 2A, 2B, and 7D, a reinforcing plate 16 made of a thin metal plate is fixed to the lower surface of the rear portion of the seat outer shell 8, and the reinforcing plate 16 and the back inner shell 12 are fixed. Are connected by a hinge 17 so as to be relatively rotatable. The front end portion of the reinforcing plate 16 is fixed to the seat outer shell 8 with a pressing plate 18 made of a metal plate.

Without using the reinforcing plate 16 may be a seat outer shell 8 and the back inner shell 12 is connected directly with the hinge 17. It is also possible to connect the seat inner shell 9 and the back inner shell 12 with a hinge, or connect the seat inner shell 9 and the back outer shell 11 with a hinge. Further, the seat inner shell 9 and the back inner shell 12 can be integrally formed of resin (in this case, it is preferable to form a hinge portion for bending the backrest 2).

  The seat inner shell 9 and the seat outer shell 8, and the back inner shell 12 and the back outer shell 11 are integrally held by a pair of male and female snap members that fit together by deformation against elasticity. Of course, it is also possible to fix with a fastener such as a screw.

Rear and rear of the seat outer shell 8 of the seat inner shell 9 shows some dimensions only rising part of which stand up are (the seat 1 while being curved loosely in a side view, with reference numeral 1a in FIG. 5 (A). ). Therefore, it can be said that the lower part of the backrest 2 is constituted by the rear portion of the seat 1, or it can be said that the seat 1 includes a waist support portion. However, in this specification, is also rising portion 1a was included as part of the seat 1 (which is intended convenient for ease of explanation.).

  The connecting portion between the seat 1 and the backrest 2 (that is, the position of the support shaft of the hinge 17) is generally at the height of the lower part of the lumbar group of the person who is seated.

(2) Details of base and seat mounting structure As shown in FIGS. 4, 5A, 8, and 9, the base 7 includes a cylindrical body 21, and an upper plate is provided inside the cylindrical body 21. 22, an intermediate plate 23, and a lower plate 24 are arranged. Each plate 22, 23, 24 is fixed to the cylindrical body 21 by welding. A bush 25 is fixed to the center of each plate 22, 23, 24 by welding, and the upper end of the leg column 5 is fitted to the bush 25.

  For example, as shown in FIGS. 3 and 4, below the seat outer shell 8, a pair of left and right stopper rods 26 that are vertically long and partially enter the base 7 are arranged. A horizontal support plate 28 is fixed to the upper end of the stopper rod 26 by welding, and the support plate 28 is fixed to the seat outer shell 8 with screws.

  Further, as shown in FIGS. 4, 8, and 11, for example, a bar seat support 27 that surrounds the bush 25 from the left and right and the rear is fixed to the lower plate 24 of the base 7 by welding (FIG. 4). Then, the upper surface of the seat support 27 overlaps with the intermediate plate 23, but actually there is a gap between the seat support 27 and the intermediate plate 23 as shown in FIG.

  The seat support 27 is formed with a support column 27a that is tilted forward in a side view and spreads left and right in a front view, and a horizontal portion 27b that is laterally horizontal is formed integrally with the tip of the support column 27a. Yes. The horizontal portion 27 b of the seat support 27 is pressed and held by the seat outer shell 8 by a holding metal fitting 29. The holding metal fitting 29 is covered with a cover 30.

  The cover 30 includes a cantilever-like projecting portion 30a that fits between the seat outer shell 8 and the horizontal portion 27b, and a rib 30b that overlaps the lower surface of the holding bracket 29. As shown, it is attached by inserting into the horizontal part 27b from the outside. For this reason, a fastener such as a screw is unnecessary.

  The overhanging portion 30a of the cover 30 is inserted between the horizontal portion 27b of the seat support 27 and the seat outer shell 8, and the lower surface of the seat support 27 is in contact with the bottom surface of the holding bracket 29 in the horizontal portion 27b state. ing. For this reason, the seat support 27 is held by the seat outer shell 8 without any backlash.

  An auxiliary stay 31 that is curved in a forwardly convex shape in plan view is fixed to the base of the left and right horizontal portion 27b of the seat support 27 by welding. Therefore, the seat 1 is also supported by the auxiliary stay 31.

  The lower end of the stopper rod 26 is a free end, and the lower end of the stopper rod 26 is located near the upper surface of the intermediate plate 23 in the base 7 in a non-sitting state. The seat 1 can tilt backward against the elastic deformation of the seat support 27. When the seat 1 tilts backward, the stopper rod 26 moves downward. The maximum backward tilt angle of the seat 1 is determined by the stopper rod 26. It is regulated by hitting the lower plate 24.

  The upper plate 22 of the base 7 has a long hole 22a (see FIG. 4) for allowing the stopper rod 26 to move downward. The intermediate plate 23 of the base 7 is notched at both left and right ends so as not to interfere with the stopper rod 26.

  An auxiliary stay 31 that is curved in a convex shape in a plan view is fixed to the base of the left and right horizontal portion 27b of the seat support 27 by welding, and the seat 1 is also supported by the auxiliary stay 31.

(3) Elevating operation lever and its mounting structure An operating lever 33 for elevating the seat 1 is disposed below the front portion of the seat 1. The operation lever 33 is manufactured by bending one bar (or pipe), and as a whole, the operation lever 33 has a shape warped in a concave shape (or bow shape) when viewed from above. Therefore, the operation lever 33 is configured to be pulled upward below the left and right corners of the seat 1. The reason for adopting such a configuration is mainly to prevent the lower leg portion from hitting the operation lever 33 when the person makes the lower leg portion enter below the seat 1.

  Next, the mounting structure of the operation lever 33 will be described with reference to FIGS. The base portion of the operation lever 33 includes a longitudinal longitudinal portion 33a extending in parallel across the left and right sides, and a laterally long horizontal portion 33b formed so as to oppose the left and right longitudinal longitudinal portions 33a. It is close to the form. And the operation piece 35 for pushing the push valve 34 of the pedestal 5 is fixed to the left and right horizontally long horizontal portion 33b by welding, and the left and right horizontally long horizontal portion 33b is held by the portion excluding the operation piece 35 The member 36 is pressed and held on the upper surface of the intermediate plate 23 of the base 7.

  The holding member 36 is notched at the left and right intermediate portions so as not to interfere with the operation piece 35, and the portion that holds the horizontally long horizontal portion 33b is bifurcated. Further, a claw 38 is formed at the rear end portion of the holding member 36 so as to be fitted into a long hole 37 formed in the intermediate plate 23 of the base 7 so as not to move upward. By being hooked from below, it is fixed by a single screw 39 so that it cannot be displaced. The holding member 36 is sandwiched from the left and right by the longitudinal longitudinal portion 33a of the operation lever 33, so that the operation lever 33 is not laterally displaced.

  When a finger is placed on the left and right ends of the operation lever 33 and pulled upward, the operation lever 33 rotates around the horizontally long horizontal portion 33b. Then, the push valve 34 of the leg column 5 is pushed down by the operation piece 35. Thus, the lock of the leg column (gas cylinder) 5 is released. In the non-operating state, the longitudinal longitudinal portion 33 a of the operation lever 33 overlaps the upper surface of the intermediate plate 23 of the base 7. For this reason, the operation lever 33 is held in a non-operating state and cannot be tilted forward.

(4). Back Frame Device Next, the back frame device 4 will be described. The back frame device 4 has a main part 4a located on the left and right outer sides of the seat 1, and the main part 4a has a rear inclined part 4b that constitutes the upper part with the front end as a boundary, and a lower part with the front end as a boundary. It is comprised by the front inclination part 4c to comprise, and has become V shape opened backward as a whole.

  A continuous portion (that is, the front end portion of the main portion 4a) of the rearward inclined portion 4b and the forward inclined portion 4c constituting the main portion 4a is curved in an arc shape in a side view. Further, the degree of inclination of the backward inclined part 4b is smaller than the degree of inclination of the forward inclined part 4c. This is because the elbow pads 42 are attached to the rearward inclined portion 4b. Further, the rearwardly inclined portion 4b and the forwardly inclined portion 4c are also gently curved in a side view so as to form a concave shape in the opposite directions.

  The left and right back frame devices 4 are each composed of unit frames 43 and 44 made of two round bars, and both round bars 43 and 44 extend substantially in parallel as a whole. In the following description, when it is necessary to distinguish between the two unit frames 43 and 44, for convenience, the one close to the seat 1 is referred to as the first unit frame 43 on the basis of the posture of the main portion 4a, and the seat The one far from 1 is called a second unit frame 44. In addition, as a material of both unit frames 43 and 44, the bar material which consists of metals, such as steel, stainless steel, and aluminum, can be used.

The first unit frame 43 and the second unit frame 44 have upward and inwardly-facing portions 43 a and 44 a that wrap around from the rear end of the main portion 4 a to the back surface of the back inner shell 12. In this case, the upper inward portion 44a of the second unit frame 44 is located above the upper inward portion 43a of the first unit frame 43 is positioned on the lower, upper inward of the left and right second unit frame 44 The portions 44a are pressed and held on the back inner shell 12 by pressing members (bearing members) 45, respectively. The holding member 45 is fixed to the back inner shell 12 with screws. The upper inward portion 44a of the second unit frame 44, the pressing member 45 and the back inner shell 12 can be relatively rotated relatively.

  In the present embodiment, the upper inward portions 44a of the left and right second unit frames 44 are integrally continuous. Accordingly, the left and right second unit frames 44 are manufactured using a single round bar. In the present embodiment, since the left and right upper inward portions 44a extend in series, there is an advantage that the tilting of the backrest 2 is smooth.

  The upper inward portion 43 a of the first unit frame 43 is set to a length that abuts or closely contacts the pressing member 45. By setting the upper inward portion 43a to such a length, the left and right positioning of the back frame device 4 and the backrest 2 is automatically performed.

The upper inward portion 43a of the first unit frame 43 and the upper inward portion 44a of the second unit frame 44 are preferably integrated by welding or the like. The back outer shell 11 overlaps the back surface of the back inner shell 12. Therefore, in order to prevent interference with the upper inward portions 43a and 44a of the unit frames 43 and 44 and the pressing member 45, the back outer shell 11 is formed with a rearward protruding portion 11a bent in a mountain shape. By forming the backward protruding portion 11a, but there will be a tunnel-shaped space between the back outer shell 11 and the back inner shell 12, this space, be closed by a cap 46 shown in FIG. 7 (C) (D) Can do.

  For example, as shown in FIG. 3, the first unit frame 43 and the second unit frame 44 are horizontally inwardly-facing downward inward portions that enter the lower part of the seat 1 in a state of being continuous from the rear end of the forward inclined portion 4c in the main portion 4a. 43b, 44b. Both the downward inward portions 43b and 44b enter the lower portion of the seat 2 behind the base 7, and forward end portions 43c and 44c are integrally connected to the tips of the downward inward portions 43b and 44b. The forward end portions 43c and 44c are fixed to the intermediate plate 23 of the base 7 by welding. In the present embodiment, the left and right horizontally long downward inwardly-facing portions 43b and 44b and forward-facing ends 43c and 44c constitute the lower connecting portion described in the claims.

  Needless to say, the cylindrical body 21 of the base 7 is cut out so as not to interfere with the forward-facing ends 43c and 44c of the back frame device 4. Further, as shown in FIG. 8, the intermediate plate 23 of the base 7 is formed with a long hole 47 and a notch 48 that overlap with the forward end portions 43c and 44c in a plan view. This is a measure for facilitating the build-up when welding 43c and 44c.

In the present embodiment, as shown in FIG. 3, the lower inward portion 43b and the forward end portion 43c of the first unit frame 43 are outside the lower inward portion 44b and the forward end portion 44c of the second unit frame 44. It is in a state surrounded by. This is because the forward end portions 43c and 44c have the same height .

The first unit frame 43 and the second unit frame 44 have different heights such that the first unit frame 43 is lower and the second unit frame 44 is higher at the rearwardly inclined portion 4b of the main portion 4a. . Then, as shown in FIG. 5 (B) , a plate material 49 inclined in a front view is fixed to the first unit frame 43 and the second unit frame 44 by welding, and an armrest 42 is attached to the plate material 49. It is fixed. The elbow pads 42 are separated into two upper and lower members, and the upper and lower members are fastened by screws (not shown) penetrating the plate 49.

In the present embodiment, the first unit frame 43 is lower than the second unit frame 44 in the main portion 4a. Therefore, the upper surface of the elbow rest 42 is inclined downward toward the seat 1 in a front view. When a person puts his elbow on the elbow rest 41, the arm may be in a posture with the arms extended to the left and right. In this case, the arm (the second arm between the elbow and the shoulder) is inclined outward. Therefore, as shown by an arrow B in FIG. 5 (B) , the elbow can be applied to the upper surface of the elbow pad 42 substantially vertically. Therefore, the elbow can be held in a stable state. This is an advantage of this embodiment.

(5) Summary When a seated person leans against the backrest 2, a large moment is applied to the top of the backrest 2, so the backrest 2 is elastically deformed by the back frame device 4, Tilt backwards. The seat 1 tilts backward by elastically deforming the seat support 27.

  In this case, a. The back frame device 4 is substantially V-shaped in a side view and has a long length so that it can be easily deformed, b. Since the lower inward portions 43b and 44b are present at the lower portion of the back frame device 4, the lower inward portions 43b and 44b are subjected to an action (torsion action) that is twisted around the axis thereof. 4 is easily deformed greatly in the direction of increasing the back tilt angle of the backrest 2; c. The forward end portions 43c and 44c are also in a state where deformation is allowed due to the twisting action and the bending action, and the back frame device 4 is greatly elastically deformed together with these ac. As a result, the backrest 2 can be greatly tilted backward.

  And since the main part 4a of the back frame apparatus 4 is substantially laterally open V-shaped in a side view, the main part 4a is not excessively deformed, so that the deformation and rigidity of the back frame apparatus 4 are easy. And can provide a comfortable rocking state for people.

  The back frame device 4 is composed of two inner and outer unit frames 43 and 44. Both the unit frames 43 and 44 have different lengths and different arrangement states depending on their heights. The method of deformation is also different. For this reason, both the unit frames 43 and 44 are deformed in a state of regulating each other. That is, a phenomenon occurs in which both unit frames 43 and 44 act as resistance against one deformation.

Then, the total elastic deformation of the two unit frames 43 and 44 becomes a resistance against the backward tilting of the backrest 2, but the unit frames 43 and 44 regulate each other as the degree of deformation increases. Thus, the backrest than the increase rate of the reclining angle of 2 increase rate of the elastic restoring force is increased as a whole for both units frame 4 3,44, so that the backrest 2 is rapidly moderately without backward leaning It will slowly tilt backwards with the reaction force. From this aspect, it is possible to improve the leaning comfort when rocking.

  Since the main portion 4a of the back frame device 4 has a substantially horizontal V-shape, a space opened forward in a side view is vacant between the main portion 4a of the back frame device 4 and the seat 1. . Therefore, for example, there is an advantage that the back frame device 4 does not get in the way even if a seated person spreads his legs. The main part 4a of the back frame device 4 is the most conspicuous part, but if the main part 41 is formed in a lateral V shape, a sharp impression is given to a person, so it can be said that the main part 4a is also excellent in terms of design.

  In this embodiment, the seat 1 is also tilted backwards. However, as a backward tilting mode of the seat, a mode in which the seated person leans back against the backrest 2 for the first time and a slight backward tilting by the seating of the person are included. Two modes can be selected. Which mode is selected depends on the setting of the strength (elastic restoring force) of the seat support 27.

(6). Second Embodiment FIG. 13 shows a second embodiment. In this embodiment, the leg 3 has a four-leg frame structure. The portion above the base 7 is essentially the same as in the first embodiment. However, the lift control lever 33 of the first embodiment is not provided (for the second embodiment does not comprise a gas cylinder, the lift control lever is not necessary first place.).

  Various forms have been proposed in the past when the leg 3 has a frame structure made of pipes or bars. The present invention can be applied to any of these conventional legs. It can also be applied to legs that will be newly created.

(7). Others The present invention can be embodied in addition to the above embodiments. For example, the main part of the back frame device can have an upper part or a lower part in a horizontal posture (in this case as well, the main part has a V-shaped configuration with a rearward opening as a whole). Further, the main part of the back frame device can be formed such that the upper part and the lower part thereof are loosely curved, for example, downwardly concave.

  When the back frame device is configured by a plurality of unit frames, the number of unit frames may be three or more. In addition, the back frame device may be constituted by a plurality of unit frames, or an end portion extending in the front-rear direction may be provided at the lower connecting portion of the back frame device and fixed to the base or the seat, The attachment of the armrest to the frame device can be invented independently of each other.

(A) is the perspective view which looked at the chair of 1st Embodiment from the front, (B) is the perspective view which looked at the chair from back. (A) is a plan view of the chair, (B) is a front view of the chair, and (C) is a right side view of the chair. It is a top view which shows the framework of a chair. It is sectional drawing of a base. (A) is a longitudinal side view, (B) is a longitudinal side view, and is a cross-sectional view taken along line BB of FIG. 5 (A). (A) is a cross-sectional view taken along the line VIA-VIA in FIG. 5 (A), and (B) is a cross-sectional view taken along the line VIB-VIB in FIG. 5 (A). 2A is a cross-sectional view of VIIA-VIIA in FIG. 2B, FIG. 2B is a side view of the cap, FIG. 2C is a CC diagram of FIG. 2B, and FIG. FIG. FIG. 5 is a sectional view taken along the line VIII-VIII in FIG. 4. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8. (A) is a top view of the holding member for raising / lowering operation levers, (B) is a BB cross-sectional view of (A). It is the XI-XI sectional view taken on the line of FIG. (A) is a sectional view taken along line XII-XII in FIG. 3, and (B) is a perspective view of the cover. It is a perspective view of the chair of a 2nd embodiment.

1 seat 2 backrest 3 legs 4 back frame device 7 base 8 seat outer shell 9 seat inner shell 10 seat cushion 11 back outer shell 11a rearward projecting portion 12 back inner shell 13 back cushion 17 hinge 41 main portion 43 of back frame device 43 the first unit frame 44 the second unit frame 43a, upper inward portion 43b of 44a back frame unit, lower inward portion 43c of the 44b back frame system, forward ends of 44c back frame unit

Claims (5)

A seat supported by a base, a backrest that can be tilted backward, and a pair of left and right back frame devices fixed to the lower surface of the base or seat;
The left and right back frame devices have a main portion that is disposed on the left and right outer sides of the seat and opens rearward in a side view, and the backrest is attached to the upper rear end of the main portion. While providing the connecting part,
In the lower rear end of the main portion in the back frame device, a lower connecting portion that enters below the seat is integrally formed, and the lower connecting portion has an end portion that extends toward the front side, The end of the connecting part is fixed to the base or seat ,
In a further, main portion of the back frame unit is formed in a substantially sideways V-shape upper and lower interval is gradually increased toward the rear end from the front end,
The structure
The left and right back frame devices are each composed of a plurality of bar-shaped unit frames extending substantially in parallel, and the plurality of unit frames are substantially parallel in plan view at least at the upper surface portion of the main portion. Extending to the
Chair. The front end portion of the main portion in the back frame device is curved in an arc shape in a side view,
The chair according to claim 1. Attach the armrest to the two unit frames which constitute the upper surface portion of the front Symbol main unit,
The chair according to claim 1 or 2. The backrest is composed of a back inner shell with a cushion on the front surface, and a back outer shell disposed on the back side of the back inner shell,
On the other hand, at the upper rear end of the main portion in the back frame device, an upward inward portion that enters between the back inner shell and the back outer shell is integrally bent, and the upper inward portion is The connecting part,
The chair as described in any one of Claims 1-3. In the back outer shell, a rearward projecting portion for avoiding interference with the upper inward portion of the back frame device is bent so as to extend over the entire left and right length,
The chair according to claim 4.

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