JP2017113464A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection strength and assemblability in a chair in which a backrest is connected only to left and right back columns.SOLUTION: Left and right back columns 10 are integrally connected with a laterally long upper joint 18. A forward engaging projection 31 projecting forward of the upper joint 18 is provided at an upper end of the back column 10. The forward engaging projection 31 is provided with an upward projecting part 31a and a downward projecting part 31b. On the other hand, a rearward engaging frame part 38 engaging with the forward engaging projection 31 is formed in a side frame 20 of a back frame body 19 constituting a backrest 3. A pocket part 43 fitted to the downward projecting part 31b from below is formed in the rearward engaging frame part 38. Because the back frame body 19 is held in a non-configurable manner with respect to the back column 10, high fixing strength can be ensured even when fastening with one screw 35.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a chair and is characterized by the structure of the backrest. The chair includes a bench.

  In a chair, a backrest is attached to a back column that can be tilted backward, and an example thereof is disclosed in Patent Document 1. That is, Patent Document 1 discloses that a lower portion of a backrest is fastened to a pair of left and right back posts with screws. The screw is inserted through the back column from the back. Therefore, left and right horizontally long covers are mounted on the left and right back columns, and the heads of the screws are hidden by the covers.

Japanese Patent Laying-Open No. 2015-13113

  In Patent Document 1, the backrest is held in a stable state only by the back column. Therefore, the overall appearance is neat. However, when the inventors of the present application studied, there was room for improvement. For example, in Patent Document 1, the backrest is fixed to the left and right back struts with two upper and lower screws, respectively. From the viewpoint of improving the efficiency of the assembly work, the fixing strength can be fastened with one screw without losing the strength. This is preferable.

  The present invention has been made in view of such a current situation, and is intended to provide an improved structure in a type in which a backrest is attached to a back column as in Patent Document 1.

  The present invention includes the invention specified in each claim. Of these, the invention of claim 1 has a backrest attached to a back strut extending upward behind the seat, and the backrest is held in a stable state only by being attached to the back strut, A fitting portion is provided on the backrest and the back column so as to be fitted from the front and rear direction so as to hold the backrest so that it cannot move left and right and cannot be tilted backward with respect to the back column, and the fitting portion is fastened by a fastener.

  According to a second aspect of the present invention, in the first aspect, two back struts are arranged on the left and right sides, and upper end portions of the left and right back struts are connected by left and right laterally elongated joints. In addition, as a fitting portion on the back strut side, a rear fitting portion that protrudes from the left and right end portions of the joint to the top and bottom and the front side is provided, while the back portion of the backrest is fitted to the backrest side. As a part, a front fitting part with a rearward opening that covers the rear fitting part is provided, and a pocket part that protrudes downward from the joint of the rear fitting part and fits a part is fitted to the front fitting part. Provided.

  According to a third aspect of the present invention, in the first or second aspect, the rear fitting portion of the back strut and the fitting portion of the front fitting portion are held so as not to move back and forth by left and right horizontally long pins inserted therethrough. ing.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the backrest includes a rear member on which the fitting portion is formed and a front member that overlaps the rear member from the front. On the other hand, the fastener is composed of a screw and a nut, and a nut is arranged on the front surface of the rear member, and the screw is inserted into the back column and the rear member from behind and screwed into the nut. And the nut is covered with a front member of the backrest.

  According to a fifth aspect of the present invention, in the fourth aspect, the back side member of the backrest is formed in a frame shape of front and rear openings having left and right side frames that are vertically long, and the seat member of the side frame is seated. The part centering on the height located in the waist | hip | lumbar part is attached to the back support | pillar by the said fitting part, and the said rear fitting part and the front fitting part are covered from the back and the inside by the cover.

  Furthermore, a lumbar support body that supports a portion of the backrest that supports the seated person's waist from behind is fitted and mounted on the side frame of the rear member of the backrest. The cover is held so as not to move inwardly from side to side.

  In the present invention, since the backrest is held by the fitting portion so as not to be tilted backward, for example, even if only one screw is fastened, it is possible to obtain a high fixing strength. Moreover, since the fitting part of the back column and the fitting part of the backrest are fitted to each other, the back column can be held so that the backrest does not slide down, so that the positioning of the backrest is facilitated. By these synergistic actions, the assembly work of the backrest can be performed efficiently.

  In the structure of Claim 2, since the right and left back struts and the joint reinforce each other, the support strength of the back struts is remarkably increased. In particular, the rigidity against torsion in a plan view is improved. For this reason, the support strength of the backrest can be improved.

  Further, since the rear fitting portion of the back column protrudes above and below the joint, the vertical length of the fitting portion can be increased while making the joint vertical width as small as possible. Also by this, the resistance against the fall of the backrest can be increased, and the support strength (fixed strength) of the backrest can be improved.

  Further, when the user's body pressure is applied to the upper part of the backrest during locking, the backrest tends to tilt backward with the upper end of the rear fitting portion as a fulcrum. Is fitted in the pocket part of the front fitting part so that it cannot be tilted backward with respect to the back strut. It is possible to suppress the load applied to the. This prevents the backrest from collapsing with the back strut even if the rear protrusion and the pocket of the rear fitting do not have an excessively strong structure (thus making the fitting as compact as possible). it can.

  When the fitting portion of the back strut and the fitting portion of the backrest are connected by a pin as in claim 3, the fitting of both fitting portions is disengaged (broken) and the backrest is disengaged. Accidents that tilt backwards can be more reliably prevented. Therefore, extremely high safety can be ensured.

  There are various types of fasteners for fastening members together, but screws are the most common and highly reliable. And when the fitting part of a back support | pillar and a backrest is fastened together with a screw and a nut like Claim 4, since it is not necessary to make a tapped hole, the effort of a process can be suppressed by that much. In the case of resin or light metal, if the screw is screwed in strongly, the female screw may be crushed and cannot be fastened. However, in claim 4, since the female screw is unnecessary, the back member of the back column or the backrest is made of resin. Even if it is made of metal or light metal, there will be no situation where fastening is impossible.

  In addition, since the nut is covered with the front member constituting the backrest, there is no problem that the nut touches human eyes and impairs the appearance without providing a dedicated cover.

  In the invention of claim 5, since the lumbar support body can support the seated person's waist from behind, the user can stably hold the posture with the body directly. For this reason, the burden on the body can be reduced. According to the fourth aspect of the present invention, since the cover for hiding the head of the screw for fixing the back column and the backrest is held by the lumbar support body so as not to be detached, the structure of the cover can be simplified accordingly.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the chair of embodiment, (A) is the perspective view seen from the front, (B) (C) is the perspective view seen from back, (D) is a right view. (A) is the isolation | separation perspective view of a base and a tilting frame, (B) is the perspective view which looked at the base from back. (A) is the isolation | separation perspective view of a main member, (B) is a front view in the state which abbreviate | omitted the mesh material, (B) is a perspective view in the state which abbreviate | omitted the mesh material. (A) is a partially separated perspective view of the back portion viewed from the back, (B) a partial perspective view of the back portion viewed from the back, (B) is a separated perspective view of the back frame body, the lumbar support body, and the connecting portion cover. It is. (A) is a separated perspective view of a back column and a back frame, (B) is a partial perspective view of a back column, and (C) is a partial perspective view of a back frame. (A) is a separated perspective view of a back column and a back frame body, (B) is a partial perspective view of a back frame body. It is a plane sectional view of a connection part. (A) (B) is a perspective view of a back frame, (C) (D) is a perspective view of a mesh material holding body. (A) is a vertical side view of the upper end portion of the backrest, (B) is a plan sectional view of the side portion of the backrest, and (C) is a vertical side view of the lower portion of the backrest. (A) is a separated perspective view of a back frame body, a lumbar support body, and a connection part cover, (B) is a rear perspective view in the state which combined the lumbar support body and the connection part cover. (A) is a perspective view in a state where the lumbar support body and the connecting portion cover are combined, (B) is a perspective view in a state where the lumbar support body and the connecting portion cover are combined with the back frame body, (C) is It is a separation perspective view of a lumbar support body and a connection part cover from a back frame. It is a plane sectional view of a mounting part of a lumbar support body.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, front / rear / left / right words are used to specify the direction, which is based on the direction of a person who normally sits on a chair. The front view is a state seen from the direction facing the seated person. Although inward and outward words are also used, the inward direction is the direction facing the longitudinal center line of the backrest 3 in the left-right direction, and the outward direction is the reverse direction.

(1). Outline of Chair First, an outline of a chair will be described with reference to FIGS. The chair of the present embodiment is a swivel chair that is frequently used for office work or the like, and includes a leg device 1, a seat 2, and a backrest 3 as main elements. The leg device 1 has leg struts (gas cylinders) 4 located in the center and branch branches extending radially, and casters are provided at the ends of the branch branches.

  As shown in FIG. 1C, a base 5 is fitted to the upper end of the leg column 4. As shown in FIG. 2, a rotation member 7 is attached to the base 5 via a horizontally long support shaft 6, and a tilt frame 8 is fixed to the rotation member 7. The rotating member 7 tilts backward against a spring (not shown). The seat 2 is supported by an intermediate member connected to the base 5 and the rotating member 7.

  As shown in FIGS. 1D and 2, the tilting frame 8 has a base 9 and left and right back struts 10 and is bent in a square shape in side view. A backrest 3 is attached. The base 9 of the tilting frame 8 has a structure in which left and right members are integrally connected by a lower joint 11 and an intermediate joint 12 (it can also be seen as a structure in which a hole is formed in a shell-like structure. .)

  The lower joint 11 overlaps the rearward projecting plate 14 provided on the rotating member 7 from above, and the pressing plate 15 overlaps the lower joint 11 from above. Then, the lower joint 11 is fixed to the rearward projecting plate 14 by screwing screws 16 inserted into the rearward projecting plate 14 and the lower joint 11 from below into the holding plate 15.

  The upper ends of the left and right back struts 10 constituting the tilting frame 8 are integrally connected by a left and right horizontally long upper joint 18. The upper joint 18 corresponds to the joint described in the claims. The back column 10 and the upper joint 18 are substantially plate-shaped, and the left and right back column 10, the upper joint 18, and the intermediate joint 12 form a shape close to a square tube. For this reason, even if it is thin, it exhibits high resistance to a backward external force, a lateral external force, or an external force that twists in a plan view. That is, even if it is thin, it has high rigidity. The tilt frame 8 is a resin molded product or an aluminum die cast product.

  The backrest 3 includes a back frame body 19 as a strength member. The back frame 19 is a resin molded product (may be a die-cast product), and is integrally connected to the upper and lower side frames 20 that are vertically long, the upper frame 21 that is integrally connected to the upper ends thereof, and the lower ends of the side frames 20. The lower frame 22 and the lower frame 22 are formed in a substantially rectangular shape. The left and right side frames 20 are fixed to the back column 10. The back frame body 19 can also be called a back frame or an outer frame.

  The backrest 3 of the present embodiment is a type that supports the body of the seated person with the mesh material 17, and the mesh material 17 is stretched on a mesh material holding frame (inner frame) 23 that overlaps the back frame body 19 from the front, A mesh material holding frame 23 is attached to the back frame body 19. The edge of the mesh material 17 is fixed to the mesh material holding frame 23 by means such as sewing or tackering (it can also be attached using a tape-like edge member).

  The mesh material holding frame 23 is formed in a similar shape to the back frame body 19, and includes a vertically long side member 24, a horizontally long upper member 25, and a lower member 26. The mesh material holding frame 23 is also a resin molded product. In relation to the claims, the back frame 19 corresponds to the rear member, and the mesh material holding frame 23 corresponds to the front member.

  The backrest 3 is provided with a pair of left and right lumbar support bodies 27 that support the occupant's waist from behind via a mesh member 17. The lumbar support body 27 is attached to an inwardly facing rearward engagement frame portion 48 (details will be described later) provided on the side frame 20 of the back frame body 19 so as to be adjustable in height.

  As can be understood from FIG. 1 (D), the upper end of the back column 10 is approximately the same height as the waist of the seated person, and the backrest 3 has a height position of the seated person's waist. It bends forward and convex in side view so as to be the foremost. The connecting portion between the back column 10 and the back frame 19 is covered with a connecting portion cover 28 from the inside (from between the left and right side frames 20) and from the back.

(2). Connection structure between the back frame body and the back column Next, a connection structure between the back frame body 19 and the back column 10 will be described with reference to FIGS. For example, as shown in FIGS. 5A and 5B, a forward engagement protrusion 31 is provided at the upper end portion of the back column 10 as a rear fitting portion. The substantially lower half of the forward engaging protrusion 31 is cut outward in the left-right direction, and therefore the lower half of the lower half of the forward engaging protrusion 31 is smaller than the upper half.

  The forward engagement protrusion 31 is provided with an upward protrusion 31 a that protrudes upward from the upper joint 18 and a downward protrusion 31 b that protrudes downward from the upper joint 18. The upper and lower protrusions 31a and 31b have a claw-like shape in a side view. In relation to the claims, the forward engagement protrusion 31 corresponds to the rear fitting portion.

  As clearly shown in FIG. 5A, the rear engagement groove 34 that has entered deeper than the front surface of the back column 10 into the laterally outer portion of the narrow portion of the forward engagement protrusion 31 in the downward protrusion 31 b. Is forming. The rear engagement groove 34 is also opened downward. A screw insertion hole 36 through which a screw (bolt) 35 penetrates from behind is formed in the upward protruding portion 31a of the forward engaging protrusion 31. As can be understood from FIG. 7, a counterbore hole 37 for receiving the head of the screw 35 is formed on the rear surface of the upward projecting portion 31 a of the forward engagement protrusion 31.

  On the other hand, a rearward engagement frame portion 38 is formed on the side frame 20 of the back frame body 19 and is fitted to the forward engagement protrusion 31 of the back column 10 so as to surround it. As can be understood from FIG. 9B, the side frame 20 has a backward concave shape and a slightly warped flat cross-sectional shape. Therefore, as shown in FIGS. The upper and lower ribs 39 and 40 and the vertically long side ribs 41 continuous with these are provided on the rear surface of the rear 20 so as to project rearward.

  When the rearward engagement frame portion 38 and the frontward engagement protrusion 31 are fitted from the front and rear, the back frame body 19 is held so as not to be displaced in both the vertical direction and the horizontal direction. For example, as can be understood from FIG. 4C, the rearward engagement frame portion 38 protrudes from the inner surface of the back frame body 19 to the left and right inward slightly.

  For example, as can be understood from FIG. 5A, a front engagement protrusion 42 that enters the rear engagement groove 34 formed in the forward engagement protrusion 31 protrudes backward in the rearward engagement frame portion 38. ing. The upper surface of the front engagement protrusion 42 is an inclined surface 42a whose height decreases toward the rear, and correspondingly, the upper surface of the rear engagement groove 34 in the forward engagement protrusion 31 is also directed rearward. Thus, the inclined surface 34a is lowered in height. Therefore, the rear engagement groove 34 and the front engagement protrusion 42 have a substantially trapezoidal shape with the upper surface inclined rearward and downward in a side view.

  At the lower end portion of the rearward engagement frame portion 38, an upward opening pocket portion 43 is formed that fits into the downward projection 31b of the forward engagement protrusion 31 from below. The pocket portion 43 is formed by denting a part of the lower rib 40 of the rearward engagement frame portion 38. Below the lower rib 40, an auxiliary recess 44 having a square shape in rear view is opened rearward.

  The rearward engagement frame portion 38 of the back frame body 19 is fitted into the forward engagement protrusion 31 of the back column 10 from the front side. However, if the rearward engagement frame portion 38 is simply translated backward, the downward projection 31b hits the front surface of the pocket portion 43. (It will be used.) Accordingly, the back frame body 19 is in a posture inclined from the reference state so that the upper end of the back frame body 19 is shifted forward, and the downward projecting portion 31b is first inserted into the pocket portion 43, and then the downward projecting portion 31b is used as a fulcrum. Then, the upward projecting portion 31 a is fitted into the forward engaging protrusion 31 by the procedure of tilting the back frame 19 backward and taking a predetermined posture.

  For example, as can be understood from FIG. 5B, the downward projecting portion 31b has a constricted shape in a side view. For this reason, it becomes easy to fit the pocket part 43 in the downward protrusion part 31b previously. Further, since the upper surface of the front engagement protrusion 42 and the upper surface of the rear engagement groove 34 are both inclined surfaces 42a, 34a, the fitting between the front engagement protrusion 42 and the rear engagement groove 34 is smooth. Guided by

  For example, as shown in FIG. 6, the upward projecting portion 31 a of the downward projecting portion 31 b and the rearward engaging frame portion 38 of the back frame body 19 are fastened together with the above-described screw 35 and a nut 45 to which the screw 35 is screwed. . Therefore, the nut 45 is disposed so as to overlap the front surface of the side frame 20 in the back frame 19.

  In this embodiment, the nut 45 has a cylindrical shape and is provided with a flange 46 at one end. The flange 46 is formed by cutting and raising a claw 46a. The nut 45 is held in a non-rotatable manner by fitting the cylinder portion of the nut 45 into the mounting hole 48 of the side frame 20 and then hitting the flange 46 with a hammer so that the claw 46 a is bitten into the receiving seat of the side frame 20. A plate nut or a hex nut may be used without using the nut 45 with the claw. In this case, it is preferable to provide a bag-like nut holding hole in which the nut is fitted so as not to rotate. As clearly shown in FIG. 6, forward ribs 51 are formed on the inner peripheral portion of the side frame 20.

  As shown in FIG. 5, the lower portion of the forward engagement protrusion 31, the side rib 41 and the front engagement protrusion 42 of the rearward engagement frame portion 38 are connected by a horizontally long pin 50. 5A, the pin 50 is inserted in the direction of the side rib 41, the forward engaging protrusion 31, and the front engaging protrusion 42, and the tip of the pin 50 is at the end of the back column 10. It has stopped.

(3) Connecting part cover 28
For example, as can be understood from FIG. 4, the upper and lower protrusions 31 a and 31 b of the forward engagement protrusion 31 are exposed rearward, and the rearward engagement frame 38 is inward (in the direction of the longitudinal center of the backrest 3). Exposed. Therefore, these are covered with a resin connection portion cover 28. Accordingly, the connecting portion cover 28 has a substantially L-shaped cross-sectional shape having a rear plate 28a and a side plate 28b (see also FIG. 7), and has a small lid portion 28c at the upper end and the lower end.

  Since the forward engaging protrusion 31 protrudes forward from the back column 10, the rear plate 28 a is cut away by the vertical width of the upper joint 18. Further, since the side plate 28 b of the connecting portion cover 28 overlaps the side rib 41 of the rearward engagement frame portion 38, the pin 50 is held by the connecting portion cover 28 so as not to be detached. Therefore, a dedicated member for preventing the pin 50 from coming off is not necessary.

  As shown by the arrows in FIGS. 4A and 4C, the connecting portion cover 28 is fitted into the connecting portion between the back column 10 and the back frame body 19 by moving laterally from between the left and right side frames 20. Is done. When set, the rear plate 28a fits into the back column 10 and is held so as not to fall. Further, as shown in FIG. 4B, a knob 27 b of the lumbar support body 27 overlaps with the side plate 28 b of the connecting portion cover 28 from the inside. For this reason, the connection part cover 28 is hold | maintained so that a horizontal movement is impossible, without taking means, such as a screw and an engaging claw. The structure of the lumbar support body 27 will be described later.

(4) Summary of connection structure In the above configuration, the back frame body 19 is held so as not to be displaced in both the vertical direction and the horizontal direction by fitting the forward engagement protrusion 31 and the rearward engagement frame portion 38. Has been. And since the downward protrusion part 31b fits in the pocket part 43, the back frame body 19 is hold | maintained so that it cannot tilt backward with respect to the back support | pillar 10. As shown in FIG. For this reason, the back frame 19 can be held in a stable state by fastening only one screw 35.

  At the time of locking, the back frame body 19 tends to tilt backward with respect to the back column 10 with the portion of the upward projecting portion 31a as a fulcrum, but the connecting portion between the back column 10 and the back frame body 19 Since the downward projecting portion 31b and the pocket portion 43 are fitted to each other at the lower end portion, the moment that has acted on the back frame body 19 can be accurately prevented and high fastening strength can be maintained.

  In addition, the front engagement protrusion 31 and the rear engagement frame portion 38 are not simply fitted to each other, but the rear engagement groove 34 of the front engagement protrusion 31 and the front engagement protrusion 42 of the rearward engagement frame portion 38 are also fitted. Since both the back support column 10 and the back frame body 19 are formed with irregularities and fitted together, the positioning of the back frame body 19 and the function of preventing backward collapse are further improved. .

  In the present embodiment, since the rearward engagement frame portion 38 protrudes vertically from the upper joint 18 and has a longer vertical length, the load on the downward projecting portion 31b and the pocket portion 43 is reduced. Ensuring strength is ensured.

  In the present embodiment, the forward engagement protrusion 31 and the rearward engagement frame portion 38 are connected by the pin 50, so that the back frame body 19 is prevented from being tilted backward with respect to the back column 10. Therefore, for example, it is possible to eliminate an accident that the downward projecting portion 31b or the pocket portion 43 is broken and the back frame body 19 is tilted backward with respect to the back column 10. Therefore, extremely high safety measures are taken.

  Further, since the connecting portion is covered with the connecting portion cover 28, the appearance can be prevented from being deteriorated. However, since the pin 50 is prevented from being pulled out by using the connecting portion cover 28, the structure is prevented from becoming complicated. ing. In addition, since the lumbar support body 27 serving as a chair element functions to prevent the connecting portion cover 28 from being detached, the connecting portion cover 28 can simplify the structure and contribute to cost reduction.

  In the present embodiment, the forward support protrusion 31 is provided on the back column 10 and the backward engagement frame portion 38 is provided on the back frame body 19, but the relationship between males and females can be reversed. It is also possible to provide a plurality of places on the back column 10 and the back frame 19 above and below the male and female fitting portions.

(5). Connection structure between mesh material holding frame and back frame body Next, a connection structure between the mesh material holding frame 23 and the back frame body 19 will be described with reference to FIGS. The connecting means between the mesh material holding frame 23 and the back frame 19 is formed on the left and right side portions, the upper portion and the lower portion, respectively. That is, the side member 24 and the side frame 20 are connected, the upper member 25 and the upper frame 21 are connected, and the lower member 26 and the lower frame 22 are connected. We also use screws for connection. Hereinafter, description will be made sequentially.

  First, as a means for connecting the side member 24 and the side frame 20, as shown in FIG. 8, a pair of positioning projections 53 that are U-shaped in front view are provided on the upper side of the side frame 20. An outward hook-like rear engagement claw 54 is projected forwardly at a position between the positioning protrusions 53.

  On the other hand, the side member 24 of the mesh material holding frame 23 has a substantially square positioning hole 55 that fits into the positioning projection 53 of the side frame 20 and a downward front that meshes with the rear engagement claw 54 of the side frame 20 from above. The engaging claw 56 protrudes backward. The positioning hole 55 is longer in the vertical direction than the positioning projection 53. Therefore, the front engagement claw 56 is engaged with the rear engagement claw 54 from above by shifting the side member 24 downward with the positioning hole 55 fitted in the positioning projection 53.

  The side member 24 is held so as not to be laterally displaced with respect to the side frame 20 by the positioning hole 55 and the positioning projection 53, and the side member is engaged by the engagement (engagement) of the front engagement claw 56 and the rear engagement claw 54. Reference numeral 24 denotes a side frame 20 that is held forward and inseparable. In FIG. 9B, a flat cross section of a portion where the positioning hole 55 and the positioning projection 53 are fitted is displayed.

  As a means for connecting the upper member 25 and the upper frame 21, as shown in FIG. 8, a plurality of downward projections 56 ′ are provided at appropriate intervals in the left-right direction on the upper member 25. Has an upper engagement hole 57 into which the downward projection 56 is fitted. Therefore, the upper member 25 is held so as not to be displaced in any of the front, rear, left and right directions with respect to the upper frame 21. FIG. 9A shows a cross section of the portion where the downward projection 56 ′ and the upper engagement hole 57 are fitted.

  As a means for connecting the lower member 26 and the lower frame 22, as shown in FIGS. 8 (C) and 9 (C), a forward hook-like stopper claw 58 projects upward from the upper surface of the lower member 26. On the other hand, a stopper step 59 is formed on the lower surface of the lower frame 22 to engage (contact) the stopper claw 58 so as not to move forward.

  The stopper claw 58 is thin so as to bend and deform. Then, the mesh material holding frame 23 is fitted into the upper engagement hole 57 of the upper frame 21 with the downward projection 56 ′ of the upper member 25 in a posture in which the lower member 26 is slightly separated from the lower frame 22. When the member 26 is pressed against the lower frame 22, the stopper claw 58 is once elastically deformed and then returned, and the stopper claw 58 is engaged with the stopper step portion 59 from behind. As a result, the mesh material holding frame 23 is also held at the position of the lower member 26 so as not to be separated from the back frame 19 forward.

  In FIG. 6A, another screw 60 is displayed under the screw 35 for connecting the back column 10 and the back frame body 19, and the side member 24 and the side frame 20 are connected by this screw 60. Are connected. Accordingly, the screw 60 passes through the side frame 20 and is screwed into the side member 24. The screw 60 passes through the side frame 20 below the nut 45.

(6). Lumbar Support Device Next, the lumbar support device will be described mainly with reference to FIGS. As clearly shown in FIG. 10, the lumbar support body 27 includes a support portion 27 a that hits the mesh material 17 from behind and a knob 27 b that protrudes backward from the support portion 27 a. The support portion 27 a overlaps the front surface of the side frame 20, and the knob 27 b protrudes rearward at a portion inside the side frame 20.

  The back frame 19 is provided with a guide groove hole 61 that is open forward and is formed at the portion of the side frame 20 where the rearward engagement frame portion 38 is provided. A slider 62 that fits into the slot 61 projects backward. The slider 62 has a U-shape that opens in the direction of the knob 27b in the rear view.

  Further, the slider 62 is divided into upper and lower parts, and an intermediate part between the upper and lower parts is a tongue piece 62a. A hemispherical stopper projection 63 is provided on the outer surface of the tongue piece 62a. On the other hand, on the inner surface of the guide groove 61 in the side frame 20, a large number of stopper grooves 64, in which the stopper protrusions 63 are engaged and disengaged, are formed in multiple stages. Therefore, the lumbar support body 27 can be held at an arbitrary height by the tongue piece 62a being elastically deformed and the stopper protrusion 63 fitting into the arbitrary stopper groove 64.

  The support portion 27a of the lumbar support body 27 is substantially quadrangular when viewed from the front, and each corner portion is rounded (see FIG. 3B for the exact shape). Further, it is gently curved in a forward convex shape in a plan view and a side view. For this reason, the mesh material 17 smoothly hits the surface of the support portion 27a, and stress does not concentrate on a specific portion of the mesh material 17. Since the lumbar support body 27 is pushed backward by the mesh material 17, it does not slip out.

  The knob 27b of the lumbar support body 27 has an inwardly open U shape having a side piece 27c and an upper and lower piece 27d in the rear view, and the side piece 27c overlaps the side plate 28b of the connecting portion cover 28 from the inside. Yes. Since the lumbar support body 27 is held so as not to move left and right by the stopper projection 63 being fitted in the guide groove 61, the connecting portion cover 28 is held so as not to move inward.

  The embodiment of the present invention has been described above, but the present invention can be embodied in various ways. For example, the application target is not limited to a swivel chair, but can be applied to a non-rotatable movable chair or a fixed chair such as a theater chair. The back strut can also be embodied in various forms as required. In the case of a chair that does not rock, it is also possible to stand up directly from the legs. It is also possible to arrange one back strut in the left and right middle part and attach the backrest to this back strut with the structure of the present invention. It can also be applied to chairs that do not have a lumbar support.

  In addition, the backrest of the embodiment was a type in which a mesh material was stretched on the back frame of the front and rear opening, but a shell-like back plate (inner shell) was adopted as a front member, and a cushion material was stretched on this. It can also be a type. In this case, the back side member of the backrest is often a shell-like outer member. It is also possible to attach a back plate (body support) that is not a mesh material, while using a back frame that opens back and forth.

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

2 seats 3 backrest 8 tilting frame 9 base of tilting frame 10 back strut 18 joint (upper joint)
DESCRIPTION OF SYMBOLS 19 Back frame as an example of back side member 20 Side frame 22 Mesh material as an example of body support which supports body pressure 23 Mesh material holding frame as an example of front side member 24 Upper member of mesh material holding frame 27 Lumber support body 28 connecting portion cover 31 forward engaging projection 31a as one example of rear fitting portion 31a upward protruding portion 31b downward protruding portion 34 rear engaging groove 35 connecting screw 38 rearward engaging frame portion 39 to 41 rib 42 front engaging protrusion 43 Pocket part 45 Nut 50 pin

Claims (5)

A backrest is attached to a back column extending upward behind the seat, and the backrest is configured to be held in a stable state only by being attached to the back column,
The backrest and the back strut are fitted from the front and rear direction to provide a fitting portion that holds the backrest so that it cannot move left and right with respect to the back strut and cannot be tilted backward, and the fitting portion is fastened with a fastener.
Chair. Two back struts are arranged on the left and right, and the upper ends of the left and right back struts are connected by left and right horizontally long joints, and the upper ends of the left and right back struts are fitted as fitting parts on the back strut side, While providing a rear fitting portion that protrudes from the left and right ends of the joint to the top and bottom and the near side,
A rear fitting front fitting portion that covers the rear fitting portion is provided as a fitting portion on the backrest side on the rear surface portion of the backrest, and the front fitting portion includes the rear fitting portion. Providing a pocket part that protrudes downward from the joint and into which a part fits,
The chair according to claim 1. The rear fitting portion of the back strut and the fitting portion of the front fitting portion are held so as not to move back and forth by left and right horizontally long pins inserted through them.
The chair according to claim 1 or 2. While the backrest has a rear member on which the fitting portion is formed, and a front member that overlaps the rear member from the front,
The fastener is composed of a screw and a nut, a nut is disposed on the front surface of the rear member, and the screw is inserted into the back column and the rear member from behind and screwed into the nut. Is covered by the front member of the backrest,
The chair as described in any one of Claims 1-3. The back member of the backrest is formed in a frame shape of a front and rear opening having upper and lower left and right side frames, and a portion centered on a height of the side frame of the seated person is It is attached to the back strut by the fitting part,
While the rear fitting portion and the front fitting portion are covered with a cover from behind and inside,
A lumbar support body that is fitted and attached from the front to the side frame of the back member of the backrest that supports the seated person's lower back is hit by the back, and the lumbar support body is provided with a rearward facing knob, The cover is held immovable in the left and right direction,
The chair according to claim 4.

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