JP5551223B2 - Chair - Google Patents

Description

  The present invention relates to a chair characterized by the structure of the backrest.

Structure of the backrest there is a wide variety in the chair, but as one type, provided with a metal back frame as strength members and this cushioned back plate which is attached to (the back inner shell) back support member such as is there.

  An example of a structure for attaching the back plate to the back frame is disclosed in the patent literature. That is, in Patent Document 1, the back frame has a configuration in which left and right vertical hooks are connected by left and right laterally long connecting hooks, and an engaging projection with a head projects forward from the upper part of the vertical hook, The lower part has a hook-shaped bearing that projects upward in a side view, while the back plate has an engagement hole into which the engagement protrusion of the vertical hook part fits and a bearing of the vertical hook part from above And a horizontal axis.

In Patent Document 1 , the engagement hole of the back plate is formed in a dharma shape in which a large-diameter portion large enough to fit and remove the head of the engagement projection and an upward slit into which only the neck portion of the engagement projection fits. The back plate is held so as not to be detached from the back frame by fitting the horizontal axis of the back plate into the bearing of the back frame while keeping the engagement projection fitted in the slit.

JP 2001-128789 A

  Patent Document 1 adopts a catch method that is an engagement between an engaging claw and an engaging hole as a means for attaching a back plate, and if such a catch method is adopted, there is an advantage that the backrest can be easily assembled. is there.

  Further, in Patent Document 1, the back frame is described as being made of metal or resin. In this case, it is understood that the resin frame is an injection-molded product, while the metal case is not clearly shown. Referring to the drawing, it is understood that the molded product is a die-cast product. Therefore, the molded product has a problem that the analysis of the stress distribution is troublesome as compared with the sheet metal processed product, and the design is troublesome.

  The present invention has been made to improve the current situation.

Chair of the present invention, an upper end fixed base and the seat to the legs, and has a Re back even other attached to the rear tiltably linked tilted frame to the base, the seat back, the intensity and back frame as a member, a back support member for supporting the occupant's body be attached to the back frame, a configuration and a back cover covering the back frame from behind,
The back frame has an up-and-down longitudinal left and right side member and a left and right horizontally-long upper member and a lower member, and is open to the front and rear, while the lower member is fixed to the tilting frame ,
The back cover includes vertical left and right side portions that cover the side members of the back frame from behind, left and right horizontal upper portions that cover the upper members of the back frame from behind, and left and right sides that cover the lower members of the back frame from behind. It has a horizontally long lower part and is open to the front and rear, the fixed part of the tilting frame with respect to the lower member of the back frame is exposed behind the lower member, and this is covered from behind by the back cover and, on the inner periphery of the front Kiura cover is provided an inner plate which covers the inner periphery of the back frame from the inside.

According to a second aspect of the present invention, in the first aspect, the front surfaces of the left and right side members in the back frame are inclined so as to recede toward the inside in a plan view, while the side portion of the back cover projects forward. The inner and outer side plates have a groove shape that opens forward.

The invention of claim 3, in claim 1 or 2, before Symbol backrest are reversed trapezoidal shape as viewed from the front.

In the present invention, the back frame is covered from behind by a back cover. For this reason, it can be easily manufactured excellent back to strength.

It is the perspective view which looked at the chair which concerns on embodiment of this invention from the front. (A) is a front view, (B) is a side view. It is an isolation | separation perspective view of the location centering on the seat. It is a perspective view which shows the attachment structure of a back frame. It is a separation perspective view of a mechanism part. (A) is the isolation | separation perspective view of a back frame and a reinforcement member, (B) is the perspective view which looked at the reinforcement member from the front. (A) is the isolation | separation perspective view of a back frame and a back inner shell, (B) is a perspective view of an upper engagement nail | claw. It is a figure which shows the structure of a back frame. It is a separation perspective view of a back frame and a back inner shell. (A) is a cross-sectional plan view of the backrest, (B) is a partially enlarged view of (A), (C) and (D) are cross-sectional views taken along the line XC-XC in FIG. 9 (A) after assembly, XD-XD FIG. 10A is a cross-sectional view taken along the line XIA-XIA in FIG. 10 showing only the upper portion of the backrest, and FIG. 10B is a cross-sectional view taken along the line XIA-XIA in FIG. FIG. (C) is a sectional view taken along the line XIC-XIC of FIG. 10 showing only the lower part of the backrest. It is a separation perspective view of a back frame and a back cover. FIG. 11A is a longitudinal side view of the upper left and right middle portions of the back frame and FIG. 10B is a sectional view taken along the line XIIIB-XIIIB of the lower portion of FIG.

  Next, an embodiment of the present invention will be described with reference to the drawings. The present embodiment is applied to a chair used by a child / student as a set with a learning desk, but of course, it can also be used for an adult chair such as an office chair.

(1). Outline of Chair First, an outline will be described with reference to FIGS. 1 is a perspective view of a chair as viewed from the front, FIG. 2A is a front view, FIG. 4B is a side view, FIG. 4 is a perspective view of a tilting frame and a back frame, and FIG. 5 is a part of a locking mechanism. FIG.

  The chair includes, as main elements, a leg 1 with casters, a base 2 fixed to the upper end of the leg 1, a seat 3 disposed above the base 2, and a backrest 4 disposed behind and above the seat 3. And an armrest device 5 as an optional product. The leg 1 is provided with a leg column (gas cylinder) 6 that is freely extendable and rotatable, and a base 2 is fixed to the upper end of the leg column 6.

  Further, the leg 1 includes five branch legs 7 extending radially, and a step plate 8 having an arc shape in plan view is fixed to three adjacent branch legs 7. On the outside of the base 2, there are a handle 9 for adjusting the elasticity of the locking spring, a lifting lever 10 for releasing the lock of the leg column 6 when adjusting the height of the seat 3, and a lock for adjusting the front and rear position of the seat 3. The front / rear lever 11 for releasing is exposed.

  Although not shown, the seat 3 includes a resin seat inner shell (seat plate) and a seat cushion stretched on the upper surface thereof, and the seat cushion is covered with a cloth from above. The seat 3 is fixed to, for example, a seat outer shell (seat receiving member) 12 shown in FIG. The seat outer shell 12 is supported by an intermediate fitting (not shown) so that the front / rear position can be adjusted, and the intermediate fitting is covered from the left and right outer sides with a cover denoted by reference numeral 13 in FIG.

As can be understood from FIG. 4, the backrest 4 includes a back frame 14 formed in a square shape in a rear view (or a front view) using a metal plate as a material. The back frame 14 serves as a strength member of the backrest 4. A resin back inner shell (back plate) 15 as a back support is attached to the front surface of the back frame 14. A back cover 16 made of resin is attached. A back cushion 17 is placed on the front surface of the back inner shell 15, and the back cushion 17 and the back inner shell 15 are covered with a bag-like cloth 18.

The back frame 14 is formed in a substantially rectangular shape in front view by left and right upper and lower left and right side members 20 and left and right upper members 21 and a lower member 22, and the lower member 22 faces forward from the lower member 22. The extending pair of left and right tilt frames 23 are fixed (fixed) by welding. A horizontally long second shaft 24 is fixed between the front ends of the left and right tilt frames 23, and a plate-like bridge member 25 is fixed between the front and rear middle portions of the tilt frames 23.

  As shown in FIG. 3C, the back inner shell 15 is formed with a large number of slits 19 for facilitating bending deformation and longitudinal deformation. As shown in a partially broken view in FIG. 1, in the backrest 4, the outer periphery of the back cushion 17 is made of a shape-retaining material 17 a that is elastic but hard to lose its shape, thereby sharpening the outer periphery. The square shape is maintained (this is the same for the seat 3).

The backrest 4 tilts backward, and the seat 3 tilts backward while retracting in conjunction with the backward tilting of the backrest 4. A few points about this point. As shown in FIG. 5, the base 2 is formed in a box shape with an upward opening, and the left and right side plates 2a are formed with a slit groove 26 that opens forward. the first axis of the left and right horizontally provided has been slidably mounted back and forth in the groove 26 cut open through the bushing. The backward movement of the first shaft is elastically supported by a locking spring (not shown) built in the base 2.

  The tilt frame 23 uses metal pipes (steel pipes) having an oval cross section, and is arranged on both the left and right sides of the base 2. The second shaft 24 fixed to the front end portion of the left / right tilt frame 23 is sandwiched from above and below by the upper center bush 28 and the lower center bush 29, and the upper and lower center bushes 28, 29 are interposed via the center metal fitting 30. The base 2 is fixed to the lower surface. The upper center bush 28 is fitted to the base 2 so as not to move left and right.

  Although details are omitted, a rearwardly elongated third shaft is provided at the rear portion of the above-described intermediate bracket, and the third shaft is connected to a bridge member 25 that is disposed across the left and right tilt frame 23 and a rear bush and a rear bracket. It is connected with. Therefore, the base 2, the intermediate metal fitting, and the tilting frame 23 form a kind of link mechanism. When the backrest 4 is locked (backward tilted), the seat 3 tilts backward while being retracted in conjunction with the rearward tilting of the backrest 4. . As shown in FIG. 5, a back gas cylinder 31 that can hold the backrest 4 at an arbitrary rearward tilt angle is disposed between the rear end of the base 2 and the lower end of the back frame 14. The back gas cylinder 31 is connected to the base 2 and the back frame 14 so as to be relatively rotatable. The back tilt of the backrest 4 and the synchro movement of the seat 3 are elastically supported by the locking spring and the back gas cylinder 31.

  A connecting projection 32 for connecting the back gas cylinder 31 protrudes from the left and right middle portions of the lower portion of the back frame 14, and a receiving member 33 is fixed to the rear portion of the left tilt frame 23. The receiving member 33 is provided with a lever (not shown) for switching the back gas cylinder 31 between a locked state and a free state.

(2). Structure of Back Frame Next, the structure of the back frame 14 will be described with reference to FIGS. 7 to 8 in addition to the previous drawings. 6A is a separated perspective view of the back frame 14 and the reinforcing member, FIG. 6B is a perspective view seen from the front of the reinforcing member, and FIG. 7A is a back frame 14 and the back inner shell 15. (B) is a perspective view of the stopper engaging claw seen from below, (C) is a perspective view of the upper engaging claw seen from below, (D) is a perspective view of the lower engaging claw, 8A is a perspective view of the upper corner portion, FIG. 8B is a rear view of the lower corner portion, FIG. 8C is a sectional view taken along the line VIIIC-VIIIC of FIG. 6A, and FIG. A) VIIID-VIIID sectional view, (E) is an EE sectional view of (B), (F) is an FF sectional view of (B), (G) is G of (B) FIG.

  As described above, the back frame 14 is composed of four vertical left and right side members 20 constituting the side, left and right lateral upper members 21 constituting the upper portion, and left and right laterally lower members 22 constituting the lower portion. Two main members are provided, and reinforcing members 36 are fixed to the left and right lower corner portions 35 by welding. Each member is manufactured by sheet metal processing using a steel plate as a material, and adjacent members are integrated by welding.

  Each member 20, 21, 22 has a flat front plate and a side plate and has a groove shape with a substantially U-shaped cross-section opened rearward. The front side is wide. Further, the side member 20 is curved with a gentle curvature in a forwardly convex shape in a side view so that the position of the seated person's waist is at the front end, while the upper member 21 and the lower member 22 are It is gently curved in a concave shape facing forward in plan view.

Each member 20 , 21 , 22 has a front plate and inner and outer side plates and is formed in a groove shape having a U-shaped cross section (in the following description, only the side member 20 has a front plate and inner / outer plates). Are denoted by reference numerals 20a, 20b and 20c, respectively). Each member 20, 21, 22 is a groove type, but the depth dimension is smaller than the width dimension.

  For example, as can be understood from FIG. 4, the front plate 20a of the side member 20 is inclined at a slight angle so as to recede as it goes inward in a plan view, and the upper member 21 and the lower member 22 are as described above. It is gently curved in a concave shape facing forward in plan view. For this reason, the upper member 21, the lower member 22, and the front surface of the side member 20 are smoothly continuous.

  Further, the front surface of the upper member 21 is slightly tilted rearward with respect to the vertical plane, and the front surface of the lower member 22 is slightly tilted forward with respect to the vertical plane. Therefore, each member 20, 21, 22 is actually in a considerably complicated form. The back inner shell 15 is curved in a forward convex shape in a side view and curved in a forward concave shape in a plan view so as to overlap the front surface of the back frame 14.

As can be understood from FIGS. 4 and 5, the front plate of the lower member 22 and the rear end portion 23a of the left and right tilting frame 23 through the rear end portion 23a of the tilting frame 23 is secured by welding to the lower member 22 Has been. Further, upright standing portions 22a are integrally formed at the left and right ends of the lower member 22, and the lower portions of the side members 20 are welded to the standing portions 22a (accordingly, precisely, the left and right sides of the back frame 14). A part of the portion is also constituted by the standing portion 22a of the lower member 22.)

In this case, as shown in FIG. 5, the upper half of the upright portion 22a is formed as a narrow width portion 22b stepped down to the left and right inner sides and the rear side by the plate thickness. And the narrow portion 22b and the side member 20 are integrally fixed together by welding.

For example, as shown in FIG. 6, a reinforcing member 36 is fitted into the lower corner portion 35 constituted by the horizontal portion of the lower member 22 and the upright portions 22 a and 22 b from the inside. The reinforcing member 36 is made of a steel plate and has an L-shape that overlaps a portion of the lower member 22 outside the tilting frame 23 and the upright portion 22a, and has an inner and outer side plate 36a and has a forward opening. It is formed in a bowl shape.

The upright portion of the reinforcing member 36 is tightly fitted to the upright portion 22a of the lower member 22 so that it cannot be displaced left and right, and the upright portion of the side plate 36a corresponds to the narrow width portion 22b of the upright portion 22a of the lower member 22. Therefore, the upright portion 22a of the reinforcing member 36 exactly overlaps the inner bottom surface of the upright portion 22a of the lower member 22.

Horizontal portion of the reinforcing member 36 is tightly overlapped with the horizontal portion of the lower member 22, and as shown in FIG. 7 (A), the end surface of the horizontal portion of the reinforcing member 36 to the rear end portion 23a of the tilting frame 23 Hit from the side. The reinforcing member 36 and the horizontal portion and the upright portion of the lower member 22 are fixed by welding, and the reinforcing member 36 and the rear end portion of the tilting frame 23 are fixed by welding.

The back frame 14, may torsional force as indicated by solid arrows A and dotted arrows B in FIG. 6 when locking is applied, the screw Ri force intensively acts on out under the corner portion 35 of the back frame 14 To do. However, in the present embodiment, since the lower corner portion 35 has a robust structure due to the presence of the reinforcing member 36, high reliability and durability can be ensured.

For example, as shown in FIG. 6, a lower engagement hole 37 for attaching a lower portion of the back inner shell 15 is vacated in a portion below the narrow width portion 22 b of the standing portion 22 a of the lower member 22 . The lower engagement hole 37 is provided with a downward slit portion 37a located at the left and right intermediate portion thereof, and is substantially T-shaped. Similarly, as shown in FIG. 7, an upper engagement hole 38 for attaching the upper portion of the back inner shell 15 is formed in the upper portion of the side member 20. The upper engagement hole 38 also has a downward slit portion 38a and is substantially T-shaped.

For example, as shown in FIG. 6, the left and right end surfaces of the front plate and the lower plate of the upper member 21 are in contact with the inner plate 20 a of the side member 20, and the contact portions of both members 21 and 20 are welded. Yes. Further, as clearly shown in FIG. 8A, the left and right end portions of the upper plate of the upper member 21 are protruding portions 21a protruding outside the inner plate 20a of the side member 20, and the protruding portions 21a A mounting hole 39 is formed.

(3). Mounting Structure of Back Inner Shell Next, the mounting structure of the back inner shell 15 will be described with reference to FIGS. 9 to 11 in addition to the previous drawings. 9 is an exploded perspective view of the back frame 14 and the back inner shell 15, FIG. 10A is a plan sectional view of the backrest 4, FIG. 9B is a partially enlarged view of FIG. 9 is an XC-XC cross-sectional view of FIG. 9 after assembly, (D) is an XD-XD cross-sectional view of FIG. 9 after assembly, and (A) in FIG. 11 is XIA-XIA of FIG. FIG. 10B is a cross-sectional view taken along the line XIA-XIA in FIG. 10 only at the lower part of the backrest 4 and is a cross-sectional view taken along the line XIB-XIB in FIG. It is XIC-XIC sectional view.

For example, as shown in FIG. 9, on the back of the left and right end portions of the back inner shell 15, a side-view-type stopper engaging claw 40 disposed near the upper end, and an upper engaging claw 41 disposed therebelow. And three pairs of engaging claws with the lower engaging claws 42 arranged near the lower end edge are formed. Further, center engaging claws 43 project downward from the left and right intermediate portions.

The stopper engaging claw 40 is shaped like a bowl as viewed from the side, and is fitted to the upper edge of the front plate of the side member 20 in the back frame 14 from above. The upper engaging claw 41 is basically in the shape of a bowl when viewed from the side, but as shown in FIG. 10 (C), a vertically long wall portion 41a is continuous with the back inner shell 15 at the left and right intermediate portions. Is formed. The upper engaging claw 41 is fitted into the upper engaging hole 38 formed in the side member 20 from the front and is slid downward. As shown in FIG. portion with the back inner shell 15 holds forward immovably by fitting the Hirohaba portion of the upper engagement pawls 41, by the wall portion 41a is fitted in the downward slits 38a of the upper engagement hole 38, back The inner shell 15 is held so as not to move left and right.

As shown in FIG. 10 (D), the lower engagement claw 42 is formed in a T shape in plan view. When the lower engagement claw 42 is fitted into the lower engagement hole 37 from the front and slid downward, as shown in FIG. 10 (D). The lower engagement hole 37 is dropped into the downward slit portion 37a. For this reason, the back inner shell 15 is held by the lower engagement claw 42 so that it cannot be displaced laterally and cannot move forward. As shown in FIG. 11B, the lower engagement claw 42 is positioned above the downward slit portion 37 a of the lower engagement hole 37 in a state in which no human body pressure is applied to the backrest 4.

  When a person's body pressure is applied to the backrest 4, the back inner shell 15 is deformed so as to extend toward a flat state, but the lower engagement claw 42 slides downward with the downward slit portion 37a fitted. As a result, the deformation of the back inner shell 15 is allowed to be deformed, and as a result, it is possible to secure a high fit by eliminating the feeling of tension.

Center engagement pawls 43 shown in FIG. 9 for example is a auxiliary one lower portion of the back inner shell 15 is held so as not to excessively forward movement, the lower end has become a recessed concave portion 43a to the forward concave The recess 43a is positioned on the rear side of the upper connecting shaft 44 of the back gas cylinder 31, as shown in FIG. The upper connecting shaft 44 is attached to a bracket 45, and the bracket 45 is fixed to a shaft support protrusion 32 provided on the lower member 22 with screws.

(4) Back cover mounting structure Next, the back cover 16 mounting structure will be described with reference to FIGS. 12 and 13 in addition to the previous drawings. 12 is an exploded perspective view of the back frame 14 and the back cover 16, FIG. 13A is a vertical side view of the left and right middle portion of the upper portion of the back frame 14, and FIG. 12B is a lower side view of FIG. It is XIIIB sectional view.

The back cover 16 is formed in a square frame shape similar to the back frame 14, and is formed in a substantially rectangular shape with side portions 16 a, an upper portion 16 b and a lower portion 16 c corresponding to each member of the back frame 14. As shown in FIGS. 6 to 8 and 12, the rear end portion 23 a of the tilting frame 23 is exposed behind the lower member 22, but this is covered from behind by the lower portion 16 c of the back cover 16.
The side portion 16a and the top 16b of the back cover 16, forward of the inner plate 16a, respectively covering the back frame 14 from the inside and outside ', 16b' and outer plates 16a ", 16b" and a, while the lower 16c is The inner plate 16c 'is provided but the outer plate is not provided. This is in normal use, the lower surface of the lower member 22 in the back frame 14 is because not to touch the person (may be provided beneath the outer plate.).

  As means for fixing the back cover 16 to the back frame 14, the left and right ends of the outer plate 16b ″ of the upper portion 16b are fixed to the upper member 21 of the back frame 14 with screws 46, and the inner plate 16a ″ of the side portion 16b is fixed. Fastening to the inner surface of the side member 20 with a screw 46 and fastening a bracket piece 47 projecting forward on the lower portion 16 c to the lower surface of the lower member 22 with a screw 46 are employed. Of course, other methods such as a catch method using an engaging claw can be employed.

The outer plate 16b ″ of the upper portion 16b of the back cover 16 can be referred to as the upper plate (or the upper surface plate) of the back cover 16. And, as described above, the upper plate 16b ″ of the back cover 16 is the back plate 14. Although fixed to the upper member 21 with screws 46, as can be understood from FIG. 11 (A), the upper plate 16b ″ of the back cover 16 is fixed to the stopper engaging pawl 40 in the back inner shell 15 as a feature of this embodiment. In other words, the end portion of the upper plate 16b ″ of the back cover 16 is a stopper portion that prevents the back inner shell 15 from moving upward.

Accordingly, the back inner shell 15 is held so as not to be detached, although the engaging claws 40, 41, 42 are simply fitted into the back frame 14. That is, the back inner shell 15 can be held so as not to be detached, although it can be easily assembled. As shown in FIGS. 10C and 10D and FIG. 13, the front plate of the back cover 16 is in contact with or close to the back surface of the back frame 19.

(5) Summary In the present embodiment, the left and right tilt frames 23 and the back frame 14 are separately manufactured and then assembled by welding. The back frame 14 is also composed of four members 20-22, and each member 20-22 is integrated by welding after being individually manufactured. Accordingly, the back frame 14 has a complicated shape bent three-dimensionally as a whole and has engagement holes 37, 38, etc., but each member 20 to 22 is made of a band plate as a material (for example, a male shape). It can be easily processed by press working using a female mold.

The back inner shell 15 can be attached very easily by dropping the engaging claws 40, 41, 42 into the side members 20 of the back frame 19, and the upper plate 16 b ″ of the back cover 16 is attached to the back inner shell 15. Since it functions as a stopper means for preventing the upward movement, the backrest 4 that can be easily assembled does not cause a problem that the back inner shell 15 is detached from the back frame 14 during use, for example.

  In the present embodiment, only the left and right sides of the back inner shell 15 are restrained by the side members 20, and there is a gap between the back inner shell 15 and the upper member 21 and the lower member 22. Therefore, it is allowed to stretch and deform so as to escape to the back side by the body pressure of the person who is seated, and thus high fit can be obtained.

Further, the back inner shell 15 is deformed so as to extend toward a flat state in a longitudinal side view due to the presence of a large number of slits 19. In this case, the back inner shell 15 is an upper plate 16 b ″ of the back cover 16. Since the upper end of the back inner shell 15 is restrained so as not to move upward, the back inner shell 15 is allowed to be deformed by escaping mainly so that the lower part of the back inner shell 15 moves downward. As a result, back slipping or shirt twisting is prevented or suppressed. Is done.

A force that is pulled inwardly on the back inner shell 15 due to the locking is applied. In this case, if the upper engagement claw 41 has a simple hook shape, the flange portion hits the inner surface of the upper engagement hole 38. engaging claws 41, a state of the beams cantilevered have Na merely hooked, since the load due to the locking occurs as large moment, we can not ensure high support strength. At first, the upper engaging claw 41 cannot be excessively enlarged.

On the other hand, when the wall 41a is provided on the upper engaging claw 41 as in the present embodiment, the wall 41a is continuous with the back inner shell 15 and can secure high rigidity against bending. The nail | claw 41 has an advantage which can ensure high intensity | strength and durability, without making it excessively thick.

Furthermore, if the lower engagement claw 42 is formed in a T shape over substantially the entire top and bottom as in the present embodiment, there is an advantage that it is possible to reliably absorb the back inner shell 15 extending and deforming in the vertical direction. Further, when the auxiliary engagement claw 40 is provided as in the present embodiment, not only the mounting strength to the back frame 14 can be further improved, but the upper auxiliary engagement claw 40 is separated from the upper end of the back frame 14 to the near side. Therefore, there is an advantage that the function of holding the back inner shell 15 so as not to move upward by the upper plate 16b ″ of the back frame 14 becomes more perfect.

In the present embodiment, an intermediate engagement hole is provided in a vertical halfway height portion of the left and right side members 20 in the back frame 14 (for example, a vertex portion that protrudes most forward in a side view), and an intermediate engagement claw of the back inner shell is provided in this. It is also possible to insert.

(6). Others The present invention can be embodied in various ways other than the above embodiment. For example, Russia Kkingu mechanism can be employed to those of various.

The back frame may be generally rectangular when viewed from the front, and may be trapezoidal or inverted trapezoidal . Also, the back frame can be processed into one piece by press working in the material a single steel plate, for example. The tilting frame can also be a single structure.

  It is also possible to configure all or a part of the constituent members of the back frame with square pipes or C-shaped channel members. Furthermore, when each member is formed in a groove shape, it can be opened forward. It is.

The engagement means is not limited to the combination of the engagement hole and the engagement claw as in the embodiment. For example, the engagement member protrudes outward, inward, or both sides to the side member of the back frame. On the other hand, it is also possible to provide the back inner shell with a hook-like engagement claw that is fitted onto the locking bar from above.

It is also possible to form the side member in a groove shape opened forward and to provide a locking bar inside thereof. Alternatively, it is possible to form an upward hook-like engagement claw on the front surface of the side member, and to engage the engagement claw of the back inner shell from above. Alternatively, when the back frame includes an upper member and a lower member, it is possible to form an engaging claw that fits the upper member and the lower member from above in the back inner shell (in this case, the upper The member and the lower member themselves function as engagement means.)

DESCRIPTION OF SYMBOLS 1 Leg apparatus 2 Base 3 Seat 4 Backrest 14 Back frame 15 Resin back inner shell as an example of back plate 16 Back cover 16b "Upper side plate of the back cover which also serves as a stopper means
16c Lower part of back cover 23 Tilt frame 20 Side member of back frame 20a Front plate 20b Inner plate 20c Outer plate 21 Upper member of back frame 22 Lower member of back frame
23 Tilt frame

Claims (3)

Upper fixed base and the seat to the legs, and has a Re other even back attached to the rear tiltably linked tilted frame to the base, the backrest, the back frame as strength members A back support body that is attached to the back frame and supports the body of the seated person, and a back cover that covers the back frame from behind,
The back frame has an up-and-down longitudinal left and right side member and a left and right horizontally-long upper member and a lower member, and is open to the front and rear, while the lower member is fixed to the tilting frame ,
The back cover includes vertical left and right side portions that cover the side members of the back frame from behind, left and right horizontal upper portions that cover the upper members of the back frame from behind, and left and right sides that cover the lower members of the back frame from behind. It has a horizontally long lower part and is open to the front and rear, the fixed part of the tilting frame with respect to the lower member of the back frame is exposed behind the lower member, and this is covered from behind by the back cover and, on the inner periphery of the front Kiura cover is provided an inner plate which covers the inner periphery of the back frame from the inside,
Chair. The front surfaces of the left and right side members in the back frame are inclined so as to recede as they go inward in plan view, while the side portions of the back cover have inner and outer side plates protruding forward and open forward. It has become a groove type,
The chair according to claim 1. Before Symbol backrest is in the inverted trapezoidal shape as viewed from the front,
The chair according to claim 1 or 2.

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