JP2020058761A - Chair - Google Patents

Abstract

To enhance safety and excellent appearance in a chair with high followability to twisting deformation of a backrest with respect to a movement of a seated person.SOLUTION: An upper end of a backrest is connected to an upper support 16 of a back frame and a lower end of the backrest is connected to a lower support of the back frame. The upper support 16 is separately constituted from a back supporter 15. A downward rod 31 drooping from the upper support 16 is rotatably held by a bearing block 32 incorporated in the back supporter 15. The downward rod 31 is partially exposed in an upper part of the back supporter 15. The exposure part is covered by an elastic cover 61 made of an elastically deformable base material such as elastomer. A fingertip of a person does not touch the downward rod 31, so as to provide safety.SELECTED DRAWING: Figure 14

Description

  The present invention relates to a chair.

  There are various types of chairs, and swivel chairs that are frequently used in offices have a leg device with casters, a seat, and a backrest as main elements, and an armrest device, a headrest, a hanger, etc. are attached as optional items.

  In addition, many swivel chairs have a locking function that allows the backrest to tilt backward. With such a locking function, the seated person can relax his / her body and continue using for a long time.

  An important factor for maintaining comfort in a chair is the fit and softness of the backrest, where the front surface of the backrest is made up of cushion material or the mesh material supports the body. Since the mesh material has excellent air permeability, it also has an advantage of preventing stuffiness.

  Now, when a seated person leans against the backrest, the centerline of the upper body is not always aligned with the centerline of the backrest, and the body leans with the upper body tilted to the right or left, or the body is twisted while leaning against the backrest. However, in these cases, the pressing force (body pressure) due to the leaning back of the seated person strongly acts on the left side or right side of the backrest.

  In general, the backrest of the chair basically has rigidity that is hardly deformed by the pressing force of the seated person. However, when the backrest has a rigid structure, the seated person's body is located on the left side of the backrest. Alternatively, when the seat occupant is biased toward the right side, a part of the seated person's body strongly hits a part of the backrest, which deteriorates comfort.

  Therefore, when the body of the seated person hits the left side or the right side of the backrest in a biased manner, the backrest is allowed to bend (twist and deform) due to the pressing force of the seated person, thereby enhancing the usability. Is proposed. For example, in Patent Documents 1 and 2, a backrest is attached to a back frame in a three-point support (or substantially three-point support) state, and left and right upper corner portions are made unsupported so that a seated person can be pushed. A configuration is disclosed which allows the left side or right side of the backrest to flex backwards under pressure.

Republished WO 2014/196630 European Patent Publication 0970639

  In Patent Documents 1 and 2, the backrest can be bent and deformed (twisted and deformed) by the pressing force of the seated person. Therefore, when the upper body is shifted to the right or left and leans against the backrest, the backrest is deformed following. Therefore, it is possible to allow the movement of the body of the seated person and soften the contact of the backrest against the body. As a result, it can be said that comfort can be improved.

  However, in Patent Documents 1 and 2, since the degree of deformation of the backrest depends exclusively on the degree of the elastic force of the backrest, it is inevitable that variations occur, and the stability of the quality is not necessarily high. .

  Further, in Patent Documents 1 and 2, the portion on which the seated person's pressing force is applied can be largely bent and deformed, but the portion on the opposite side to the portion on which the seated person's pressing force is applied is hardly deformed in the opposite direction. Therefore, it can be said that the followability of the backrest as a whole is not necessarily high.

  The present invention has been made against the background of such a current situation, and it is an object of the present invention to provide a chair having high followability of deformation of the backrest with respect to movement of the body of a seated person in a state of higher perfection. .

The present invention is
"A seat and a backrest, and a back frame disposed behind the backrest are provided, and an upper end portion of the back frame is an upper support to which an upper end portion of the backrest is attached, and the upper support is provided below the upper support. It is mounted so that it can pivot horizontally about the longitudinal axis about the part.
In the basic configuration
"A boundary between the upper support and a portion below the upper support is covered with a cylindrical elastic cover, and the elastic cover is connected to both the upper support and a lower portion thereof."
It is configured as.

According to a second aspect of the present invention, in the first aspect,
"The back frame includes vertically extending back pillars arranged in the left-right intermediate portion, and the upper support rotatably holds a vertically long circular rod at a bearing portion at an upper end portion of the back pillar. It is a structure in which it is connected so as to be horizontally rotatable via the pivoting means that
While the rod projects downward from the upper support, the back strut has a bearing portion that rotatably holds the rod, and the rod is partially exposed above the back strut. And
The elastic cover is made of elastomer and surrounds the exposed portion of the rod, and is formed such that the outer peripheral surface is substantially flush with the outer peripheral surface of the fixing portion. "
It is configured as.

According to the invention of claim 3, in claim 2,
"The upper and lower regulating plates are respectively held inside the upper and lower ends of the elastic cover so as not to rotate relative to each other,
Among the upper and lower regulating plates, the upper regulating plate is held by the upper engaging portion that fits when the upper regulating plate is moved upward so as not to be rotatable relative to the upper support,
Among the upper and lower regulating plates, the lower regulating plate is held by the lower engaging portion that fits when the lower regulating plate is moved downward so as not to be rotatable relative to the upper end portion of the back strut,
The upper and lower engaging parts are hidden inside the elastic cover. "
It is configured as.

  In the present invention, since the upper support is held so as to be horizontally rotatable (horizontally rotatable) with respect to the lower part thereof, when the pressing force of the seated person acts biasedly on the right side or the left side of the backrest, The backrest can be accurately deformed. Therefore, even if there is some variation in the strength of the backrest, the backrest can be accurately twisted and deformed by following the movement of the body of the seated person. Further, since the lower end of the backrest does not turn horizontally, the body of the seated person is stably held.

  Further, since the backrest is largely twisted and deformed, the seated person can twist the body while keeping the back in close contact with the backrest in the widest possible range. Therefore, the fit of the body to the backrest can be improved.

  As described above, the chair of the present invention has an excellent advantage that has never been obtained, but since the upper support is horizontally swiveled, a boundary appears between the upper support and a lower portion thereof, and the chair is used for a long period of time. If powder is generated and drops due to wear during use, or if there is a gap at the boundary, there is a concern that the skin may be drawn into the boundary when a person puts a fingertip on it.

  On the other hand, in the present invention, since the boundary portion is covered with the elastic cover, even if powder is generated due to abrasion, the powder does not drop to the outside and deterioration of aesthetics can be prevented. In addition, the problem that the skin of the fingertip is pulled into the boundary can be eliminated, and high safety can be secured. Therefore, it can greatly contribute to the improvement of quality.

  If the upper support is provided with a rod and the back support is rotatably held by the back support as in claim 2, the rod can have a sufficient length to retain its strength. Therefore, the back support should be made as thin as possible. The required strength can be secured while slimming down.

  Further, since the rod has the exposed portion, for example, even if the backrest or the back column has unevenness in size, the unevenness can be absorbed by changing the vertical length of the exposed portion. Also in this respect, the stability of quality can be improved. Further, since the outer peripheral surface of the elastic cover and the outer peripheral surface of the back column are aligned so as to be flush with each other, the appearance is excellent. The “same surface” in claim 2 means a state in which a person can recognize the same surface at a glance. Therefore, there may be some steps.

  In the second aspect, it is preferable that the elastic cover has its upper end fixed to the upper support and its lower end fixed to the back strut. As a fixing means in this case, a screwing can be considered, but in this case, the head of the screw is exposed to the outside, which may impair the aesthetics. Also, screwing in the screw is troublesome.

  On the other hand, if the structure of claim 3 is adopted, the elastic cover is held by the upper support and the back strut via the upper and lower restricting plates so as not to rotate relative to each other, but the restricting plate and the engaging portion are inside the elastic cover. Because it is hidden in, the aesthetics do not deteriorate. Further, since the restriction plate only needs to be fitted in the engaging portion, the mounting can be performed very easily.

It is a figure which shows the chair of 1st Embodiment, (A) is a front perspective view, (B) is a rear perspective view, (C) is a rear perspective view only of a back part. (A) is a front view, (B) is a rear view, (C) is a back view of only the back portion, and (D) is a side view of the back portion only. (A) is a side view and (B) is a plan view. (A) is a perspective view showing a skeleton, (B) is a rear perspective view, and (C) is a separated perspective view. (A) is an exploded perspective view of a seat portion, (B) is an exploded side view of constituent members of the seat portion, and (C) is an isolated perspective view of a back strut and a center cover. (A) is a separation perspective view seen from the back, and (B) and (C) are plan views showing the movement of the backrest. (A) is an isolated front view of a main member, (B) is a front view showing a relationship between a seat and a back frame, (C) is an isolated rear view, and (D) is a plan view of a back frame. (A) is an isolated perspective view seen from the rear, (B) is an isolated perspective view showing the connection relationship between the lower end of the backrest and the back frame, and (C) is a vertical side surface of the connection part between the lower end of the backrest and the back frame. FIG. 1D is a vertical cross-sectional side view of the connecting portion between the upper end of the backrest and the back frame. (A) is a perspective view of the back frame and the back cover separated from the rear, (B) is a perspective view of the back frame and the back cover separated from the front, and (C) is an upper support. FIG. 3D is a perspective view of the end of the lower support seen from the front, and FIG. 6D is a perspective view of the end of the lower support seen from the front. (A) is a perspective view of the back strut frame as seen from the front, (B) is a vertical cross-sectional side view of the back frame, and (C) is a sectional view taken along line CC of (B). (A) is a perspective view of a back strut, a pivot unit and an upper support, and (B) is a rear perspective view of the back strut and a pivot support unit. (C) is an upper perspective view of the elastic cover. FIG. 6D is a perspective view of the elastic cover separated from the upper side. (A) is a front view showing the relationship between the pivot support unit and the upper support, (B) is a separated front view with the elastic cover separated, (C) is a front view with only the elastic cover separated, (D) is a front view in which the constituent members are separated. It is a rear separation perspective view showing the structure of a pivot unit. The figure which shows the structure of a pivot support unit, (A) The whole isolation perspective view seen from back, (B) The whole isolation perspective view seen from the front, (C) A movable cam and a lower bearing block FIG. It is a figure which shows the mesh type chair which is 2nd Embodiment, (A) is a front view, (B) is a rear view. It is a front separation perspective view of a mesh type chair.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following, front and rear / left and right wording is used to specify the direction, but this direction is specified as the state viewed from a person who normally sits down. The front view direction is the direction facing the seated person.

(1). Outline of First Embodiment First, an outline of the first embodiment will be described. The chair of this embodiment is applied to a swivel chair that is frequently used in offices and the like. As shown in FIGS. 1 and 2, the chair includes a seat 1, a backrest 2, a back frame 3 to which the backrest 2 is attached, and a leg device 4 as main components. A lumbar support device 5 is arranged behind the backrest 2. The chair also includes an armrest device 6 and a headrest (or shoulder rest) 7 as optional items.

  For example, as shown in FIG. 1, the leg device 4 has a group of branch legs provided with casters. Further, as shown in FIG. 5, a base body 9 is fixed to a leg support (gas cylinder) 8 arranged in the center, and the back frame 3 is connected to the base body 9 via a joint member 10 so as to be tiltable rearward. ing. To be precise, as shown in FIGS. 4 (A) and 4 (C), a forward facing portion 3a is integrally formed at the lower end of the back frame 3, and the forward facing portion 3a is fixed to the joint member 10 to form a joint member. As shown in FIG. 5B, the reference numeral 10 is connected to the base body 9 so as to be tiltable rearward. In any case, the chair of this embodiment is a rocking type in which the backrest 2 tilts backward against the elastic means.

  As roughly shown in FIG. 5, a seat outer shell 12 is attached to the base body 9 via an intermediate metal fitting 11 so as to be able to move backward, and the rear portion of the seat outer shell 12 and the joint member 10 are relatively rotated. It is movably connected. Therefore, the seat 1 retracts in association with the rearward tilting of the backrest 2. The seat 1 is attached to the seat outer shell 12. A slide portion 12a (see FIG. 5A) for adjusting the front-rear length of the seat 1 is attached to the seat outer shell 12.

  As can be understood from FIG. 1C, the backrest 2 of the present application has a cushion material 13 stretched on the front and back of a synthetic resin backboard (back inner shell) 2a, and the entire front and back are covered with a bag-shaped skin material. It has a different structure. In many drawings such as FIGS. 1A and 1B and FIGS. 2A and 2B, the cushion material 13 is omitted and only the back plate 2a is shown.

  The back plate 2a has such strength that it is easily bent and deformed by a pressing force caused by a seated person leaning against it. In particular, a large number of horizontally long slits are formed in a region behind the waist of the seated person in order to facilitate deformation. Therefore, the backrest 2 is easily deformed by the lumbar support device 5. The back plate 2a can also be deformed so as to be recessed rearward.

(2). Back frame For example, as shown in FIG. 6, the back frame 3 includes a vertically-supported back pillar 15 located at an intermediate portion on the left and right, and a horizontally-supported upper support 16 mounted horizontally on the upper end thereof. It has left and right lower supports 17 integrally provided at the lower end of the back column 15. Naturally, the left and right ends of the upper support 16 and the tip of the lower support 17 are free ends. The back support 15 and the upper support 16 are made of synthetic resin (aluminum die-cast products and sheet metal products can also be used).

  For example, as shown in FIG. 6, the upper support 16 has a bowed shape in plan view such that it is recessed toward the front (expanded toward the rear), and the backrest 2 of the backrest 2 is provided at both left and right ends thereof. The left and right ends are connected. Therefore, there is a large space between the upper support 16 and the backrest 2. Due to the existence of this space, the upper end portion of the backrest 2 is allowed to be stretched and deformed backward (deformed) by the pressing force (body pressure) of the seated person.

  On the other hand, as clearly shown in FIG. 7, for example, the lower support 17 is curved so that the upper surface and the lower surface are higher toward the tip in rear view, and the lower surfaces of the left and right lower supports 17 and the back column 15 are formed. The lower surface formed with the lower surface (that is, the lower surface of the back frame 3) is also a curved surface bulging downward. Therefore, the back frame 3 has a shape similar to an anchor as a whole. Alternatively, it can be said that the shape is similar to a rounded arrow.

  Regarding the degree of bending of the upper surface of the lower support 17, the degree of bending of the lower surface is slightly large. Therefore, the lower support 17 has a slightly smaller vertical width toward the tip. Further, as shown in FIGS. 1B and 1C, for example, the lower support 17 extends forward in a state of holding the rear portion of the seat in a plan view, and the armrest device 6 is attached to the tip portion thereof. ing.

  As clearly shown in FIG. 7D, the lower support 17 has a width that decreases toward the tip in a plan view. Therefore, while holding the rear portion of the seat 1 from behind, the outer surface of the lower support 17 has an appearance as if it converges on the outer surface of the seat 1.

  For example, as clearly shown in FIGS. 7A and 7B, a protrusion 1a is provided on the rear portion of the seat 1 so as to have a shape similar to the shape of the upper surface of the lower support 17 in front view and rear view. . For this reason, even if the tip of the lower support 17 is warped upward, a sense of unity with the seat 1 is formed, and there is no discomfort in terms of design. The protrusion 1a of the seat 1 also exerts a holding effect on the buttocks of the seated person, and contributes to improvement of the stability of the seated person's body.

  As can be understood from FIG. 7 (D), the lower surface of the backrest 2 has a curved surface bulging downward, but the curved surface of the lower surface of the backrest 2 has substantially the same shape as the lower curved surface of the back frame 3. . Therefore, the design is unified.

  For example, as shown in FIG. 7C, the back surface of the back frame 3 is covered with a center cover 18 and side covers 19. That is, the center cover 18 covers the entire back pillar 15 and a part of the lower support 17, and the side cover 19 covers the rear surface of the front half of the lower support 17. These covers 18 and 19 are fixed to the back frame 3 by screws inserted into the back frame 3 from the front side. FIG. 9 shows a screw insertion hole 20 provided in the back frame 3 and a tap hole 21 provided in the center cover 18.

  Further, as shown in FIGS. 5 (C) and 10 (C), ribs 18a are provided on the right and left side edges of the center cover 18 so as to project forward, while the ribs 18a are fitted on the rear surface of the back column 15. 18b is formed. Therefore, the center cover 18 is held so as not to be laterally displaced.

(3). Connection structure of back frame and backrest As shown in FIG. 8 (A), downward hook-shaped locking claws 22 are formed on the left and right ends of the back plate 2a that constitutes the backrest 2. Engagement frame portions 23 into which the locking claws 22 are fitted from above are formed at both left and right ends of the upper support 16 in the back frame 3.

  Further, as shown in FIG. 8 (B), tapered rectangular protrusions 24 in a shape in which a head portion of a quadrangular pyramid is cut (a trapezoidal shape in which each four-sided surface is a quadrangular shape) are directed rearward at both left and right ends of a lower end of the backrest 2. On the other hand, a tapered rectangular recess 25 into which the tapered rectangular protrusion 24 is inserted is formed at the tip end of the lower support 17, and the tapered rectangular protrusion 24 is screwed with the screw 26. Have been pulled into.

  The screw 26 is inserted through the lower support 17 from the rear side, while the forward-facing square pocket hole 27 is formed in the tapered square protrusion 24 of the backrest 2, and the nut 28 fitted into the pocket hole 27 in a non-rotatable manner. The screw 26 is screwed in.

  Since the upper end of the backrest 2 is fitted into the engagement frame portion 23 of the upper support 16, the backrest 2 cannot be detached from the backframe 3 simply by pulling in the tapered rectangular recess 25 of the backrest 2 with two screws on the left and right. Can be attached to. The tapered prismatic projection 24 firmly enters the tapered rectangular recess 25 by the wedge action, so that the backrest 2 is fixed by the two screws 26 in a rattling-free state.

  Since the upper support 16 is warped so as to be recessed toward the front, there is a space between the upper support 16 and the backrest 2. There is a space between the lower support 17 and the backrest 2 as described above. The backrest 2 has four corners connected to the upper support 16 and the lower support 17, and is attached to the back frame 3 in a four-point support state. Therefore, the backs of the left and right side portions of the backrest 2 are open. Therefore, the backrest 2 can be easily elastically deformed so as to be recessed rearward by the pressing force of the seated person. This makes it possible to ensure high fit.

  The back plate 2a that constitutes the backrest 2 has an elastic strength such that a person can easily bend the back plate 2a as a single body. In the embodiment, the front and rear surfaces of the back plate 2a are covered with the cushion material 13, but it is also possible to dispose the cushion material 13 only on the front surface (however, if the cushion material 13 is also disposed on the rear surface as in the embodiment, the back plate 2a). It has the advantage that the background and slits of 2a cannot be seen through from behind.) It is also possible to cover the back plate 2a only with a skin material such as cloth, or to use the back plate 2a in a bare state.

  As shown in FIG. 8A, a rearward mounting piece 7a is provided on the lower end of the headrest 7, while a mounting hole 7b into which the mounting piece 7a of the headrest 7 is fitted is formed in the upper support 16. The attachment piece 7a is fixed to the upper support 16 with a screw (not shown). The mounting piece 7a is formed as a metal fitting built in the headrest 7.

(4). Turning Structure of Upper Support Next, the horizontal turning mechanism of the upper support 16 will be described mainly based on FIGS.

  The upper support 16 is attached to the back support column 15 so as to be horizontally rotatable via a pivotal support unit 30 as an example of a shaft support means. As shown in FIG. 14, for example, the pivot unit 30 includes a downward rod 31 fixed to the left and right intermediate portions of the upper support 16, an upper bearing block 32 that rotatably holds the downward rod 31, and an upper bearing block 32. And a lower bearing block 33 arranged below. The “block” may be restated as a member.

  The upper end of the downward rod 31 is fitted into and fixed to the upper support 16, but the upper end of the downward rod 31 is provided with a pair of anti-rotation ribs 34 protruding on both sides of the axial center. A mounting hole 35 in which the upper end portion of the downward rod 31 is non-rotatably fitted is formed in the left and right intermediate portion of the shaft 16. Then, the downward rod 31 is fixed to the upper support 16 by the upper screw 36. The screw penetrates a part of the upper support 16 and is screwed into the detent rib 34. Therefore, the rotation preventing rib 34 has a tap hole.

  As shown in FIG. 14, in a portion of the downward rod 31 that is fitted to the upper bearing block 32, a stopper projection 38 having a C-shape in plan view that spreads in the circumferential direction except the front surface portion thereof is integrally formed (or separately. On the other hand, the upper bearing block 32 is formed with a concave groove 39 into which the stopper projection 38 of the downward rod 31 is fitted so as not to move up and down.

  Further, as shown in FIG. 10 (C), the back support column 15 is formed with a bearing concave surface 40 that comes into close contact with the front surface of the downward rod 31, and the downward concave rod 40 is formed by the bearing concave surface 40 and the upper bearing block 32. It is rotatably held. Therefore, in the present embodiment, the downward rod 31 corresponds to the shaft described in the claims, and the upper bearing block 32 and the bearing concave surface 40 correspond to the bearing portion described in the claims.

  A small space 41 is provided between the left and right side portions of the bearing concave surface 40 and the left and right front surfaces of the stopper protrusion 38. The front and rear widths of the left and right spaces 41 have the same size. The stopper projection 38, the bearing concave surface 40, and the space 41 are an example of a stopper means that restricts the turning range of the upper support 16, and the vertically long end surface of the stopper projection 38 contacts the front surface of the space 41, whereby the upper support 16 and the back support pillar. The maximum horizontal turning angle relative to 15 is restricted. The stopper means may have another structure.

(5). Returning means (elastic resistance imparting means)
A portion of the downward rod 31 slightly below the stopper protrusion 38 is a small diameter portion 31a, and the small diameter portion 31a is fitted in the lower bearing block 33. Then, the fixed end surface cam 43 having continuous irregularities in the circumferential direction is formed on the step surface formed on the downward rod 31 by forming the small diameter portion 31a, while the movable cylindrical body 44 is fitted from below onto the small diameter portion 31a. The movable end surface cam 45 that engages with the fixed end surface cam 43 is formed on the upper surface of the movable cylindrical body 44.

  Further, the lower bearing block 33 is formed with a circular hole 46 into which the movable cylindrical body 44 is vertically movably fitted. The inner diameter of the circular hole 46 is substantially the same as the outer diameter of the downward rod 31. As shown in FIGS. 13 and 14, a coil spring 47 for biasing the movable tubular body 44 upward is fitted into the circular hole 46 as an example of elastic means. Instead of the spring 47, an elastic body such as rubber can be used. As shown in FIG. 10B, the lower bearing block 33 is fixed to the downward rod 31 by a screw 33a inserted from below.

  As shown in FIGS. 13 and 14, whirl-stop ribs 49 project from the left and right side surfaces of the movable tubular body 44, while whirl-stop grooves 50 into which the whirl-stop ribs 49 are fitted from above in the lower bearing block 33. Is formed. Therefore, the movable tubular body 44 is held so as to be vertically movable and non-rotatable with respect to the lower bearing block 33.

  For example, as can be understood from FIG. 13, the lower bearing member 33 is fixed to the upper bearing member 32 by two vertically long screws 53 which are inserted into the lower bearing member 33 from below. Therefore, as shown in FIG. 13, the first pocket portion 55 is formed on the rear surface of the upper bearing member 32, and the nut 54 into which the vertically elongated screw 53 is screwed is non-rotatably fitted into the first pocket portion 55.

  For example, as shown in FIG. 13, the upper bearing member 32 and the lower bearing member 33 (the pivot support unit 30) are built in the recess 51 formed in the back strut 15, and the upper bearing member 32 and the lower bearing are The member 33 is fixed to the back column 15 by front and rear long horizontal screws 58 (see FIG. 14) which are inserted into the back column 15 from the front side. Therefore, the second pocket portion 60 is formed on the back surface of the upper bearing member 32 and the lower bearing member 33, and the nut 59 into which the horizontal screw 58 is screwed is non-rotatably held in the second pocket portion 60.

  The fixed end surface cam 43 of the downward rod 31, the movable cylindrical body 44 having the movable end surface cam 45, and the coil spring 47 constitute a returning means for returning the upper support 16 to the reference posture. That is, when the upper support 16 tries to turn, resistance is given to the turning by the engagement of the upper and lower cams (cam surfaces) 43 and 45, and when the external force on the upper support 16 becomes larger than a certain amount, the movable cylindrical body is moved. 44 is moved downward against the spring 47. As a result, the upper support 16 horizontally turns. Further, when the pressing force of the seated person on the upper support 16 is released, the movable cylindrical body 44 moves upward, and the upper and lower cams 43 and 45 come into close contact with each other. As a result, the upper support 16 returns to the reference posture. Even when the upper support 16 is in the reference posture, the spring 47 is pressurized (pressurized) to some extent.

  When the end cams 43 and 45 are used as the returning means as in the embodiment, the members are vertically arranged, so that there is an advantage that the members can be made compact and the whole can be built in the back column 15. Further, the external force acting on the upper support 16 acts on the spring 47 via the cam surfaces 43 and 45, but the frictional resistance of the cams 43 and 45 can amplify the resistance of the upper support 16 against horizontal rotation. Therefore, although the spring 47 is small, it is possible to provide appropriate resistance to the horizontal rotation of the upper support 16.

  The horizontal rotation angle of the downward rod 31 is regulated by the stopper protrusion 38, but the movable cylindrical body 44 is set so as not to rotate. The upper and lower cams 43 and 45 are continuously formed in the circumferential direction in order to apply a rotational couple to the downward rod 31 to smooth the rotation.

  The upper support 16 horizontally turns against the elasticity of the spring 47, but when the upper support 16 horizontally turns, a twisting external force (rotational moment) acts on the back support column 15. Further, in this embodiment, the back column 15 is set to have a strength such that the back column 15 can be twisted and deformed by the pressing force of the seated person.

  When the pressing force of the seated person acts on the left side or the right side of the backrest 2, as shown in FIGS. 6 (B) and 6 (C), with the lower end of the backrest 2 fixed to the lower support 17, the upper support 16 Turns horizontally. Therefore, the backrest 2 is largely twisted and deformed in a plan view (note that the parallel diagonal lines shown in FIGS. 6B and 6C are measures for clearly indicating the outer shape of the backrest 2 and are not a cross-section display. .).

  Since the backrest 2 is largely twisted and deformed by the horizontal rotation of the upper support 16 in this manner, the strength of the backrest 2 is set so that the backrest 2 is easily bent and deformed. Even if the person having a small size has a small pressing force on the backrest 2, the backrest 2 can be easily deformed. Therefore, the ability of the backrest 2 to follow the movement of the body can be significantly improved.

  Furthermore, since the backrest 2 is entirely twisted and deformed, the close contact between the back of the seated person and the backrest 2 can be improved. As a result, it is possible to improve the followability of the backrest 2 with respect to the movement of the body while ensuring high fit. This can significantly improve the quality of the chair.

  Then, the backrest 2 can first be twisted and deformed against the elasticity of the spring 47, and then can be twisted and deformed against the elasticity of the back strut 15. By such two-stage torsional deformation, the backrest 2 can be appropriately deformed in accordance with the movement of the seated person's body in accordance with the degree of the pressing force applied. Therefore, high quality can be secured. The back column 15 may be strong enough not to be twisted and deformed.

(6). Downward rod cover structure For example, as shown in FIGS. 1B and 2B, there is a certain distance between the upper end of the back support column 15 and the lower end of the upper support 16. Therefore, a part of the downward rod 31 is exposed to the outside of the back column 15 and the upper support 16. Therefore, as shown in FIGS. 1C and 2C, the exposed portion of the downward rod 31 is covered with an elastic cover 61 made of an elastic resin such as an elastomer. The elastic cover 61 has a bellows-like structure.

  For example, as shown in FIG. 14 (A), the back support column 15 has a gutter-like shape that opens rearward, and when the center cover 18 is attached, the overall shape in plan view is narrow in the front. It is trapezoidal. Therefore, as shown in FIG. 14, the elastic cover 61 is also formed in a cylindrical shape having a trapezoidal shape in plan view, and the outer peripheral surface of the elastic cover 61 and the outer peripheral surfaces of the back support column 15 and the center cover 18 are formed on substantially the same surface. Therefore, it is excellent in aesthetics.

  As shown in FIGS. 11C and 11D, step portions 62 and 63 are formed on the upper end surface and the lower end surface of the elastic cover 61, respectively, and the regulation plates 64 and 65 are relative to the step portions 62 and 63. It is fitted so that it cannot rotate. Further, as shown in FIG. 14 (A), the upper regulation plate 64 is formed with an inward cutout groove 66 that fits into the rotation preventing rib 34 of the downward rod 31. Therefore, the upper end of the elastic cover 61 is held by the lower end of the upper support 16 so as not to rotate relative to it.

  In the present embodiment, the detent rib 34 provided on the downward rod 31 and the inward cutout groove 66 formed on the upper regulating plate 64 constitute the upper engaging portion described in the claims. The inward cutout groove 66 of the upper regulation plate 64 can be fitted into a projection provided on the lower surface of the upper support 16. Further, the upper regulation plate 64 and the upper support 16 may be provided with engaging portions of other forms.

  On the other hand, as shown in, for example, FIG. 13 and FIG. 14A, a spacer plate 67 is laid on the upper surface of the upper bearing block 32 so as to be relatively non-rotatable, and the left and right engaging projections 68 are provided on the upper surface of the spacer plate 67. On the other hand, the lower regulation plate 65 is formed with an inward cutout groove 69 that fits into the engagement projection 68 of the spacer plate 67. Therefore, the lower end of the elastic cover 61 is held so as not to rotate relative to the upper bearing block 32 (and the back support column 15).

  As shown in FIG. 13, left and right protrusions 70 are formed on the upper surface of the upper bearing block 32, while downward holes (not shown) for fitting the protrusions 70 are formed in the spacer plate 67. . In this case, as shown in FIG. 5 (C), a hook-shaped portion 18c is formed at the upper end of the center cover 18 so that the protrusion 70 overlaps from the front side, and the spacer plate is provided for the protrusion 70 and the hook-shaped portion 18c. 67 is fitted. Therefore, the upper end of the center cover 18 is held so as not to be displaced backward. Instead of using the spacer plate 67, the lower regulation plate 65 may be locked so as not to rotate relative to the upper bearing block 32.

  As described above, the elastic cover 61 has the upper end held relatively non-rotatably by the upper support 16 and the lower end fixed non-rotatably by the upper bearing block 32. Therefore, when the upper support 16 horizontally turns, It is twisted and deformed against elasticity. Therefore, the boundary between the upper support 16 and the back support 15 can be covered while allowing the upper support 16 to turn horizontally. As a result, it is possible to ensure safety and improve aesthetics.

  Further, since the elastic cover 61 is in close contact with the lower surface of the upper support 16 and the upper surface of the back support column 15, the upper and lower regulation plates 64 and 65 are held so that they cannot move up and down. Therefore, the restricting plates 64 and 65 are held in place so that they cannot be pulled out only by being fitted in the anti-rotation ribs 34 or the like from the vertical direction. In this case, if the elastic cover 61 is slightly compressed in the vertical direction, the close contact with the upper support 16 and the back support 15 can be improved.

  In the present embodiment, the upper support 16 turns against the elastic force of the elastic cover 61. Therefore, the elastic cover 61 also functions as spring means of the returning means. Therefore, it is possible to ensure that the upper support 16 returns to the reference posture while reducing the size of the spring 47. It is also possible to return to the reference posture only by the elastic cover 61 without using the spring 47.

  When the elastic cover 61 is formed in a bellows shape as in the embodiment, the bending deformation can be facilitated. Therefore, it is possible to prevent the upper support 16 from being resistant to horizontal turning, and to facilitate the torsional deformation of the backrest 2. Further, when it is formed in a bellows shape, it can be expanded and contracted in the vertical direction, so that the elastic cover 61 can be easily stretched to the upper support 16 and the back support column 15 against the elasticity thereof. Therefore, it is possible to prevent the elastic cover 61 from rattling.

  In the present embodiment, the upper support 16 is rotatably attached to the upper end portion of the back strut 15, but the back strut 15 is composed of two upper and lower members that relatively rotate against the spring means, and the upper member It is also possible to fix the upper support 16 to. In this case, the elastic cover 61 may be arranged between two members that are vertically separated.

  It is also possible to construct the back support column 15 by three or more members arranged vertically and connect the members vertically adjacent to each other so as to relatively rotate against the spring means (returning means). In this case, although there are a plurality of relative rotating parts, each part may be covered with an elastic cover.

(7). Second Embodiment FIGS. 15 and 16 show a second embodiment applied to the mesh type. That is, the backrest 2 has a structure in which a mesh material 81 is stretched over a back frame 80 that is open in the front and back, and includes a lumbar support device 5, an armrest device 6, and a headrest 7 as in the first embodiment. .

  The back frame 80 is made of synthetic resin, and has left and right side members 82 that are long in the vertical direction, a horizontal upper member 83 that is integrally connected to the upper ends of the side members 82, and a horizontal shape that is connected to one end of the lower ends of the side members 82. And a lower member 84 of the lower member 84. For example, it has an elastic strength that can be easily twisted and deformed by a person in a state where the lower member 84 is not attached to a chair.

  The mesh material 81 is attached to the back frame 80 via the tape materials 85 and 86 clearly shown in FIG. Specifically, outwardly projecting bosses 87 are formed in multiple stages on the left and right tape members 85 that are vertically long and vertically, and the bosses 87 are engaged with the engagement grooves 88 formed on the inner peripheral plate of the side member 82. Is fitted into. The edge portion of the mesh material 81 overlaps with the inner surface of the tape material 85, and the side members 82 overlap with the left and right end portions of the mesh material 81 and are wound around from behind.

  On the other hand, as clearly shown in FIG. 16, locking pieces 89 projecting outward in the vertical direction are formed side by side in the left and right longitudinal tape materials 86 arranged vertically, while the upper member 83 is formed. An engagement hole 99 into which the locking piece 89 is fitted is formed on the opposing surface of the lower member 84 and the lower member 84. The upper and lower ends of the mesh member 81 are fixed to the inner surfaces of the upper and lower tape members 86, and the upper and lower members of the mesh member 81 wind the upper member 83 and the lower member 84 from the outside.

  As described above, since the entire circumference of the back frame 80 is wrapped around with the mesh material 81, it is possible to suppress the material of the back frame 81 from being exposed as much as possible and improve the appearance. Further, the tape materials 85 and 86 can be easily attached.

  In the backrest 2 with mesh specifications, the inner periphery of the back frame 96 can be seen through. As can be understood from FIG. 15, the rear view shape (the same front view shape) of the upper surface (inner surface) of the lower member 84 is substantially the same as the curved surface formed by the upper surfaces of the left and right lower supports 17 in the back frame 3. It is made of curved surface. For this reason, the lower member 84 and the lower support 17 have a uniform design and have a neat appearance.

  Further, as can be understood from FIG. 15, the shape of the upper surface of the lower member 84 is substantially the same as the concave surface formed by the left and right protrusions 1a of the seat. Therefore, the shape of the rear portion of the seat 1, the shape of the lower member 84 in the back frame 80, and the shape of the left and right lower supports 17 in the back frame 3 are formed uniformly.

  Although illustration is omitted, the connection structure of the back frame 80 and the back frame 3 is the same as that of the first embodiment. Therefore, the elastic cover 61 is arranged between the upper support 16 and the back column 15.

  Although the embodiments of the present invention have been described above, the respective inventions of the present application can be variously embodied. For example, the present invention can be applied to a chair of a type in which the backrest does not tilt backward. It is also possible to adopt a configuration in which the upper support is divided into left and right two members, and the respective parts are attached so as to horizontally rotate with respect to a back frame such as a back strut.

  The form of the elastic cover can be arbitrarily set according to the form of the back support. For example, when the back column is circular, the elastic cover may also be circular.

  The present invention can be embodied in a chair. Therefore, it can be used industrially.

1 seat 2 backrest 3 back frame 15 back strut 16 upper support 17 lower support 30 pivotal support unit 31 as a pivotal support means 31 downward rod (axis) constituting the pivotal support means
32 Upper bearing block (bearing part) that constitutes the bearing means
33 Lower Bearing Block 34 Detent Rib 61 Elastic Covers 64, 65 Control Plates 66, 69 Inward Notch Grooves That Configure Engagement Parts 67 Spacer Plate 70 Engagement Protrusions That Configure Engagement Parts

Claims (3)

A seat and a backrest, and a back frame disposed behind the backrest are provided, and an upper end portion of the back frame is an upper support to which an upper end portion of the backrest is attached, and the upper support is a portion below the upper support. Is configured so that it can be horizontally swiveled around an axial center of the vertical direction,
A boundary portion between the upper support and a lower portion thereof is covered with a tubular elastic cover, and the elastic cover is connected to both the upper support and a lower portion thereof,
Chair. The back frame is provided with vertically long back pillars arranged in the left-right intermediate portion, and the upper support rotatably holds a vertically long circular rod at a bearing portion at an upper end portion of the back pillar. It is a structure in which it is connected so as to be horizontally rotatable via a shaft support means
While the rod projects downward from the upper support, the back strut has a bearing portion that rotatably holds the rod, and the rod is partially exposed above the back strut. And
The elastic cover is made of an elastomer, and surrounds the exposed portion of the rod, and the outer peripheral surface is formed to be substantially flush with the outer peripheral surface of the fixing portion.
The chair according to claim 2. Upper and lower regulating plates are respectively held inside the upper and lower ends of the elastic cover so that they cannot rotate relative to each other,
Among the upper and lower regulating plates, the upper regulating plate is held by the upper engaging portion that fits when the upper regulating plate is moved upward so as not to be rotatable relative to the upper support,
Among the upper and lower regulating plates, the lower regulating plate is held by the lower engaging portion that fits when the lower regulating plate is moved downward so as not to be rotatable relative to the upper end portion of the back strut,
The upper and lower engaging portions are hidden inside the elastic cover,
The chair according to claim 2.

Images