JP4947577B2 - Chairs and back supports - Google Patents

Description

  The present invention relates to a chair used in an office or the like, and more particularly, to a chair having a back support rod that has been improved in terms of use and manufacturing without impairing strength, and a back support rod.

As for the back support rod of the conventional chair, at least almost the entire region of the back support rod main body is formed solid by molding, and when an elbow is attached to the back support rod main body, as shown in Patent Document 1 etc. In general, a raised portion is partially provided on the mounting surface (side surface) of the back support rod main body, and a structure for alignment and connection of the elbow is formed in the raised portion.
JP 2006-122399 A

However, when such a raised portion is provided, there are disadvantages that the mold of the back support rod main body becomes complicated and expensive, and that it is easily limited to a design that can be made only by molding. Such inconvenience becomes more prominent as the mounting position of the member is increased. In particular, when it is necessary to provide a shaft portion or the like around the back support rod main body, the mold design becomes more complicated and difficult. .

  The present invention has been made paying attention to such problems, and can be simply configured to ensure a degree of design freedom, and various attachment modes and additional attachments of members to the main body. It is an object of the present invention to provide a new and useful chair and back support that can easily cope with the above.

  In order to achieve this object, the present invention takes the following measures.

  That is, in the chair of the present invention, a pair of back support rods that support the back on the left and right side portions of the base portion, the back support rod has a substantially U-shaped cross section at least in the entire body portion, Of these, an inner opening is formed integrally with the inwardly U-shaped part, and an outer opening is formed integrally with the outwardly U-shaped part.

When configured in this way and the member is attached at the opening, there is no raised portion or the like on the side surface or the like of the main body portion. For this reason, a metal mold | die can be simplified, while it aims at cost reduction and the design which can be made also with a sheet metal etc. becomes easy. And since many openings can be provided by this, it becomes possible to attach various members appropriately from the inside and outside of a back support rod. In addition, when attaching a shaft part or bearing part to the main body part, it becomes easy to make it around while suppressing the complexity of the mold by suppressing the complexity of the mold of the main body part. When is made of sheet metal, the same structure can be easily realized by welding the shaft portion, the bearing portion, and the like.

In particular, in order to facilitate the production of the main body and to ensure rigidity, it is desirable that the main body has a substantially rectangular parallelepiped shape and is mainly configured from a surface extending linearly with respect to the longitudinal direction.

In order to prevent the deformation of the opening, it is effective to form the inner opening and the outer opening alternately along the longitudinal direction.

In order to ensure sufficient internal space while maintaining strength, the outer wall of the back support rod is positioned as the back vertical wall inside the inner opening, and the inner wall of the back support rod is positioned inside the outer opening. It is desirable to position it as

Thus, in order to attach a member appropriately to the opening portion of the back support rod main body having a flat wall surface, it is preferable to form a female screw portion in the opening portion by using the rear vertical wall.

In particular, a partition is provided between the openings, and the upper and lower portions of the partition are connected by the upper wall and the bottom wall of the back support rod, respectively. It is preferable to be in a closed state.

From the viewpoint of the member mounting function, as a preferable form of the opening, the inner periphery of the inner opening has a tapered shape that gradually decreases the opening toward the outside, and the inner periphery of the outer opening gradually decreases the opening toward the inner side. One having a tapered shape is mentioned.

From the viewpoint of mold molding, it is reasonable that the taper shape on the inner periphery also serves as the taper taper at the time of molding.

In order to reduce the cost and improve the quality of molding without damaging the strength, it is preferable that the back support rod is made of a molded body having an equal thickness in almost the entire region.

As a specific embodiment of the chair, at least the inner opening located on the extended end side functions as a back attachment, and the outer opening located in an adjacent position functions as an elbow attachment. Are listed.

Even when the distance between the pair of back support rods is widened from the base end portion toward the tip end portion, it is desirable that the opening portion is opened in a direction parallel to the spine width direction.

As a back support rod, an inner opening portion and an outer opening portion are integrally formed, and the cross section including the longitudinal direction and the opening direction forms a substantially U-shape in each opening portion, and this is already installed. Even if it arrange | positions at the right-and-left both sides of the base of this, and supports a back, the chair of this invention can be comprised effectively.

  Since the present invention has the above-described configuration, it is possible to design and manufacture with a back support die, design and manufacture with sheet metal, and increase the degree of freedom in selecting the mounting position and mounting direction of members. It becomes possible to provide a new and useful chair.

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

  As shown in FIGS. 1 to 5, the chair according to this embodiment rotates the back support rod 3 on both sides of the chair body in which the base 2 is rotatably attached to the leg blades 11 via the support 12. The seat 4 and the back 5 are associated with the base 2 and the back support rod 3 so as to be capable of being synchronized with tilting.

  The base 2 is composed of a support base 21 rotatably attached to the support column 12 and a seat mounting portion 22 disposed on the support base 21. The support base 21 has a support projecting laterally from the base. A base end 3 a of the back support rod 3 is rotatably attached via a shaft 61. The seat mounting portion 22 has a front portion connected to the front end of the support base portion 21 via a slide mechanism including a long hole 21a and a pin 22a, and a rear portion supported on a support shaft 62 constructed between a pair of back support rods 3. It connects so that it can rotate through 22b. Then, with the seat 4 attached to the seat mounting portion 22 and the back 5 attached to the extended end 3b of the back support rod 3, the back support rod 3 is tilted backward about the support shaft 61, whereby the arrow in FIG. As shown, the rear portion of the seat mounting portion 22 is moved rearward and downward by the support shaft 62, and the front portion of the seat mounting portion 22 is moved rearward by a sliding motion in the long hole 21a of the pin 22a. A synchro tilt operation in which the rearward tilting operation of 5 and the rearward downward sinking operation of the seat 4 are interlocked is caused. The base 2 itself does not incorporate a lock mechanism for locking the spine 5.

  In such a configuration, the present embodiment enables the back support rod 3 to be directly attached to the back support rod 3 while making the back support rod 3 compact and smart, and directly attaches an optional member such as a headrest to the back 5. To get you attached.

  In this embodiment, the back support rod 3 is made of aluminum die-casting, and as shown in FIGS. 6 to 8, at least the main body 3c has a substantially U-shaped cross section over almost the entire area, and appears in FIG. Inner openings 3d and 3f are integrally formed in the inwardly U-shaped part, and outer openings 3e are integrally formed in the outwardly U-shaped part appearing in FIG.

The main body 3c has a substantially rectangular parallelepiped shape composed of an inner wall 31, an outer wall 32, an upper wall 33, and a bottom wall 34. These wall surfaces extend linearly along the longitudinal direction of the back support rod 3, and A first inner opening 3d is formed on the extended end 3b side, an outer opening 3e is formed at a position adjacent to the base end side, and a second inner opening 3f is formed at a position adjacent to the base end side. The first inner opening 3d functions as a back support rod attaching portion, and is partitioned by an outer wall 32, an upper wall 33, a bottom wall 34, and a partition wall 35 as shown in FIGS. 8 (a) and 8 (b). The cross section is inwardly U-shaped and opens toward the inside and the extended end. The outer opening 3e functions as an elbow attachment, and as shown in FIGS. 8A and 8C, the outer opening 3e is crossed by an inner wall 31, an upper wall 33, a bottom wall 34, and a pair of partition walls 35 and 36. It has an outward U-shape and is open to the outside. As shown in FIGS. 8A and 8D, the second inner opening 3f has a U-shaped cross section inwardly defined by an outer wall 32, an upper wall 33, a bottom wall 34, and a pair of partition walls 36 and 37. It is open to the inside. The inner side of the second inner opening 3f is further divided into four small openings by a vertical partition wall f1 and a horizontal partition wall f2, which is a stealing for making the wall thickness uniform.

  That is, the outer wall 32 of the back support rod 3 exists as a back standing wall inside the first inner opening 3d, and the inner wall 31 of the back support rod 3 serves as a back standing wall inside the outer opening 3e. The screw holes 3d1 and 3e1 for attaching the back support rod 3 and the elbow 6 are provided in the standing vertical walls, respectively.

  For example, in the first outer opening 3e shown in FIG. 7, the upper and lower portions of the pair of partition walls 35 and 36 are connected to each other by the upper wall 33 and the bottom wall 34 of the back support frame 3, respectively. In the second inner opening 3f shown in FIG. 6, if the vertical partition wall f1 and the horizontal partition wall f2 are ignored, the upper and lower portions of the pair of partition walls 36 and 37 are respectively separated from each other. Connected by the upper wall 33 and the bottom wall 34 of the support 3, the inner periphery is entirely closed in a circular shape. Of course, all the inner peripheries of the small openings that subdivide the inside opening 3f are also closed. These structures are effective in securing the strength of the opening. Since the first inner opening 3e needs to insert a protrusion 54 of the back 5 described later, the inner periphery opens to the rear end side. Since the interior is filled densely with the five protruding portions 54 inserted, there is no problem in strength.

On the other hand, as shown in FIGS. 8A and 8B, the inner peripheries of the inner openings 3d and 3f have a tapered shape that gradually decreases toward the outer side, and the inner peripheries of the outer openings 3e gradually open toward the inner side. The inner taper shape is a mold (part shown) that is configured by setting a parting line at a position that passes through substantially the center of the outer wall 32 and the inner wall 31 of the back support rod 3. (Omitted).

As shown in FIGS. 5 to 7, the back support rod 3 has a bearing portion 71 through which the support shaft 61 is inserted into the upper wall 33 in the vicinity of the base end 3 a, and the upper wall 33 in the vicinity of the extended end 3 b. Each of the bearing portions 72 through which the support shaft 62 is inserted is formed by providing a raised portion by molding and mounting a resin bush. A rotation restricting pin 63 (see FIGS. 1 and 5) that restricts the rotation range of the spine 5 is inserted into the shaft hole 73 located on the base end 3 a side so as to protrude from the support base 21.

In the above, not only the inner wall 31, the outer wall 32, the upper wall 33, the bottom wall 34, and the partition walls 35 to 37 of the main body portion 3 c of the back support rod 3, but also the shaft hole 73 and the bearing portions 71 and 72 of the base end portion 3 a. If the entire region of the back support rod 3 including the periphery of the holes to be formed is a molded body having an equal thickness, and the holes forming the shaft hole 73 and the bearing portions 71 and 72 are also considered as inner openings, these inner openings The cross section is U-shaped in almost all regions including the portion.

As shown in FIGS. 4 and 9 and the like, the pair of back support rods 3 formed in this manner is attached to the base 2 in a state where the distance between the pair of back supports 3 extends from the base end 3a toward the extension end 3b. However, the opening direction of each of the openings 3d, 3e, and 3f is set to be parallel to the spine width direction (in other words, the direction of the support shafts 61 and 62). For this reason, when viewed from the back support rod 3, as shown in FIG. 9, for example, the direction in which the elbow 6 is inserted into the opening 3d (that is, the opening direction of the opening 3d) is the longitudinal direction of the back support rod 3. A certain angle is formed with respect to the orthogonal direction.

As shown in FIG. 1, the back support rod 3 formed in this way is extended to the rear of the seat 4 so that its extended end 3 b does not become higher than the seat surface.

Then, as shown in FIGS. 1, 4 and 5, the spine 5 is directly attached to the extended ends 3b of the pair of back support rods 3 distributed to the left and right sides of the base 2 as described above.

The back 5 is formed by resin integral molding as shown in FIGS. 1 to 3, and is a single-turn frame-like back frame 5 x composed of an upper frame part 51, a lower frame part 52, and left and right side frame parts 53, The side frame 53 is formed in the shape of a substantially U-shape in which a substantially middle position in the vertical direction protrudes most forward in a side view, and is composed of a tension member 5y provided on the inner side of the back frame 5x. And the lower frame part 52 has comprised the curved shape from which a plane cross section becomes concave toward the front, as shown in FIG.4, FIG.5 and FIG.10. And the back support rod connection part 54 is integrally formed in two places right and left in the front side of the said lower frame part 52 located in the lower part of the spine 5. FIG.

  The back support rod connecting portion 54 is integrally provided with a projection 54a from the front surface of the lower frame portion 52 toward the front, and the first inner opening 3d that opens the projection 54a at the extended end 3b of the back support rod 3. And a bolt is inserted from the inside into a through hole 54b provided in a part of the projection 54a so as to be fastened to the female thread 3d1 (see FIG. 8) of the back support rod 3. The stepped portion 54a1 provided on the protrusion 54a in the fitted state is abutted against the end surface 3b1 of the extended end 3b of the back support rod 3. As shown in FIG. 1, the back support rod 3 extends substantially linearly in the side view in the rear direction, and in this embodiment, the spine 5 is attached to the extended end 3b at the shortest distance. As shown in FIG. 2, the position of the back support rod 3 in the width direction is a portion below the seat 4 and entering inward from the side edge. The position in the front-rear direction is based on the position shown in FIG. The end 3a is the approximate center of the seat 4 in the front-rear direction and a slightly forward portion of the support column 12.

  On the other hand, this chair usually takes out the back locking mechanism which is normally configured in the base 2 to the outside of the base 2, and as shown in FIGS. For this purpose, as shown in FIGS. 4 and 10, etc., a lock mechanism attaching portion 55 is provided at the center in the width direction of the lower frame portion 52 located at the lower side portion of the back 5.

In forming the lock mechanism mounting portion 55, paying attention to the fact that the flat cross section of the lower frame portion 52 of the spine 5 is curved in a concave shape toward the front, and when the spine 5 is viewed from the side, A pair of upper and lower horizontal ribs 56a and 56b are provided in a state where they are not projected forward. These lateral ribs 56a and 56b extend at both ends along the lower frame portion 52 and are connected to a pair of left and right projecting portions 54a constituting the aforementioned back support rod connecting portion 54. And the lock mechanism attaching part 55 is formed between these horizontal ribs 56a and 56b.

As shown in FIG. 10, the lock mechanism attaching portion 55 is provided with a pair of vertical ribs 55a facing each other in the back width direction while being supported by the horizontal ribs 56a and 56b as shown in FIG. When a shaft hole 55c is formed as a bearing portion through which the shaft 55b is inserted, the vertical rib 55a is also viewed from the side in relation to the flat cross section of the lower frame portion 52 being curved forward. It is configured to fit in the recess.

Then, one end 7a of the gas spring mechanism 7 is rotatably supported by a support shaft 64 provided at the rear part of the base 2 as shown in FIGS. 1, 3, 4, 10 and the like, and a shaft formed at the other end 7b. The hole 71 is inserted between the left and right vertical ribs 55a constituting the lock mechanism mounting portion 55 to match the shaft holes 55c formed in the vertical ribs 55a, and in that state, the shaft 55b is inserted from the side and inserted into these. The gas spring mechanism 7 is attached between the base 2 and the spine 5 by passing it through.

That is, when the back support rod 3 rotates around the support shaft 61 together with the back 5, the gas spring mechanism 7 having one end 7a attached to the support shaft 64 behind the support shaft 61 has the back 5 to which the other end 7b is attached. The lock mechanism mounting portion 55 is compressed as it gradually approaches the support shaft 64, and is locked again at a required compression position, so that the back seat is held in an appropriate synchronized tilt state. When the locked state is released, the returning force to the posture of FIG. 1 is developed.

Furthermore, as shown in FIGS. 11 and 12, the back 5 described above is integrally formed with a tension member attaching portion 57 and an option attaching portion 58.

Specifically, two grooves 57a and 58a are formed in parallel on the outer periphery of the upper frame portion 51 and the left and right side frame portions 53 of the back frame 5x over substantially the entire area along the circumferential direction of the back frame 5x. The groove 57a located at the front side functions as the tension member attaching portion 57 by itself, and the role of the option attaching portion 58 for attaching the option member 8 such as the headrest 81 to the groove 58a located at the rear side. I am doing so.

That is, in this embodiment, a tension member 5y in which a plate-like attachment piece 5y2 is integrally formed around the mesh ground 5y1 is prepared, and the attachment piece 5y2 of the extension member 5y is provided as the upper frame portion 51 and the left and right side frame portions. 53, and the lower end of the tension member 5y is fixed by an appropriate structure, for example, a hook claw 52a provided on the lower frame portion 52 of the back 5 as shown in FIG. Thus, the upholstery material 5y is attached to the front portion of the spine 5. In this state, as shown in FIG. 1, the front groove 57a is closed by the tension member 5y on the side surface of the back frame 5x and the like, and the rear groove 58a circulates in a slit shape.

At this time, as shown in the cross section of the back frame 5x in FIG. 12, a gap S is formed between the tension member 5y and the front surface 5x1 on the inner peripheral side of the back frame 5x. There is a portion, and the inner peripheral side of the back frame 5x including this portion and the groove 58a formed on the outer peripheral side of the back frame 5x described above constitute the option mounting portion 58 of the present invention.

As an optional member 8, for example, a headrest 81 is composed of a main body attaching portion 81a and a clamping piece 81c that is attached to and detached from the main body attaching portion 81a by a screw 81b, and the upper frame portion 51 of the back frame 5x is interposed therebetween. A pair of facing portions 81d and 81e shaped to embrace is formed, and a recessed portion 81f whose inside is wider than the opening edge is formed between the facing portions 81d and 81e. Then, after receiving the upper frame portion 51 of the back frame 5x in the portion that becomes the concave portion 81f with the clamping piece 81c detached, the clamping piece 81c is fitted and tightened in a direction to narrow the concave portion 81f using the screw 81b. By applying force, the upper frame portion 51 of the back frame 5x is sandwiched between the facing portions 81d and 81e, and the headrest 81 is attached in a state of holding the back frame 5x. In this way, the headrest 81 is attached across the portion facing the gap S on the inner peripheral side of the upper frame portion 51 from the groove 57a on the outer peripheral side of the upper frame portion 51. In this state, the front surface 5x1 of the sandwiching piece 81c is smoothly continuous with the front surface of the upper frame portion 51 of the back frame 5x, and can function as a tension material receiving surface when the tension material 5y is bent. I have to.

Incidentally, FIG. 14 shows this state as seen from the back side. In FIG. 14, a hanger 82 is also attached as another optional member 8 at the same time, avoiding interference with the headrest 81.

As shown in FIG. 15, the hanger 82 is composed of a gate-shaped hanger body 82a and a sandwiching piece 82b that is attached to the lower ends of the two legs 82a1 of the hanger body by screws. As in the headrest 81, the mounting structure is such that the upper frame portion 51 is sandwiched between the opposing pieces and tightened using the groove 58a. The legs 82a1 are positioned on both sides of the body attachment portion 81a of the headrest 81. The hanger 82 is attached to the upper frame portion 51 of the back frame 5x located at the rearmost position of the back 5 as shown by an imaginary line in FIG. Clothes can be positioned in an empty space on the back side. Note that what is indicated by reference numeral 83 in FIG. 14 is a lumbar support shown as another optional member 8, and a groove 59 similar to the above is provided on the inner periphery of the side frame portion 53 of the back frame 5x, and both ends of the groove 59 are provided at both ends. It is shown that attachment of such a member is possible by inserting 83a.

As described above, in the present embodiment, when the chair is formed by attaching a pair of back support rods 3 that support the back 5 to the left and right side portions of the base portion 2, at least the main body portion 3 c is substantially the entire region. The inner openings 3d, 3f and the like are integrally formed in the inwardly U-shaped portion, and the outer opening 3e and the like are integrally formed in the outwardly U-shaped portion. It is what I did.

With this configuration, at least almost the entire area of the back support rod main body 3c is U-shaped in cross section, so that the mold of the main body 3c portion can be made extremely simple, and the cost can be reduced. Designs that can be made can be easily accommodated. And since many opening parts 3d etc. can be provided by this, it becomes possible to attach various members appropriately from the inside and outside of a back support rod as needed. Even when the bearing portions 71, 72, etc. are formed as described above, by suppressing the complication of the mold of the main body 3c, it is possible to avoid such complication of the mold and to make such a structure around the periphery. It can be easily performed.

In particular, the main body 3c has a substantially rectangular parallelepiped shape and is mainly configured from a surface extending linearly with respect to the longitudinal direction, so that the main body 3c becomes simpler and not only improves manufacturing convenience, but also ensures rigidity. Can be effective.

In these, if the opening is biased inward or outward, the strength of the entire back support 3 is likely to be partially reduced. In the present embodiment, the first inner opening 3d and the outer opening are alternately arranged along the longitudinal direction. Since the portion 3e and the second inner opening 3f are formed, the load can be evenly distributed, and the required rigidity can be obtained even if there are many openings 3d, 3e, 3f, etc. as shown in the figure. It is possible to effectively prevent deformation of the openings 3d and the like.

In this case, the outer wall 32 of the back support rod 3 is located inside the inner openings 3d and 3f as a back standing wall, and the inner wall 31 of the back support rod 3 is located inside the outer opening 3e as a back standing wall, respectively. Since the opening ends of the openings 3d, 3e, and 3f are supported by the inner wall 31 and the outer wall 32, which are the rear standing walls of the adjacent openings, the strength of the opening ends is maintained at the same time. The inner space for inserting the member from inside and outside can be efficiently and sufficiently secured without making the back support rod 3 wide, and the member such as the elbow 6 can be appropriately inserted to the required depth.

In addition, since the internal thread portions 3d1, 3e1 are formed inside the openings 3d, 3e, etc. using the inner wall 31 and the outer wall 32, which are the standing vertical walls, even if the wall surface of the back support rod 3 is flat In addition, it is possible to effectively secure an installation place when a member is inserted into the openings 3d and 3e and attached. When the member is not attached, the cover can be appropriately attached using the female thread portions 3d1, 3e1.

Further, partition walls 35, 36, and 37 are provided between the openings 3d, 3e, and 3f. The upper wall 33 and the bottom wall 34 of the back support 3 are respectively provided between the upper and lower portions of the partition walls 35, 36, and 37. In the opening 3e and the like that are connected by the pair of partition walls 35 and 36, the inner periphery is all closed, so that the opening 3e and the like have a structure that conforms to the honeycomb. Strength can be improved.

Further, the inner periphery of the inner openings 3d, 3f, etc. has a tapered shape that gradually decreases the opening toward the outside, and the inner periphery of the outer opening 3e, etc., has a tapered shape that gradually decreases the opening toward the inside. Therefore, if the same taper shape is given to the openings 3d, 3e, 3f, etc. and the protrusion 54 of the back 5 and the base end of the elbow 6 are inserted, the member is firmly fitted. Accordingly, the positioning of these members on the back support rod 3 is also accurately performed.

In this case, since the taper shape of the inner periphery also serves as a punching taper at the time of mold forming, a structure that contributes to both the mold punching stool and the member mounting stool can be obtained.

Furthermore, since the back support rod 3 is a molded body having almost the same thickness in almost the entire region, it is possible to disperse the load appropriately so that it does not become weak locally, the material cost can be reduced, and at the time of molding Since the cooling rate becomes uniform, the effect of preventing shrinkage can be expected.

In such a chair, considering that the back support rod 3 is essentially provided with the back 5 and the elbow 6, at least the inner opening 3 d that opens to the extended end 3 b functions as a back attachment portion. If the outer opening 3e that opens to the adjacent position functions as an elbow mounting portion and other openings are formed as necessary based on these, the back applied to the chair is used. It is possible to design an effective opening for the support.

In the illustrated chair, the distance between the pair of back support rods 3 widens from the base end 3a toward the extended end 3b, but the openings 3d, 3e, etc. are only parallel to the back width direction. Since the openings 3d are opened in the direction, the depth of the openings 3d and the like, and therefore the amount of swallowing of the members such as the elbows 6 can be reduced compared to the case where the openings 3d and the like are provided in the direction orthogonal to the longitudinal direction of the back support rod 3. It can be secured without difficulty.

Furthermore, as long as the back support rod 3 as described above is configured, the chair of the present invention can be effectively configured only by arranging it on the left and right sides of the existing base and supporting the back.

In addition, when the back support rod 3 as a whole is molded into a substantially uniform thickness as described above, if the outer opening 3e is tapered so that the opening gradually decreases toward the inside, the inner openings 3d, 3f that are adjacent to each other are naturally formed. Since it has a tapered shape that reverses the taper, that is, the opening gradually decreases toward the outside, the advantage of rationally forming a structure that firmly connects the members in a positioning state from both inside and outside is remarkable. . The manner in which the base end of the elbow 6 is tapered and inserted into the outward opening 3e from the outside is as described above. For example, the protrusion 54 of the back 5 described above is tapered in the inward opening 3d on the rear end side. A mode in which the shape is inserted from the inside, a mode in which a connecting rod that connects the left and right protrusions 54 is configured other than the illustrated example, and an end portion of the connecting rod is tapered to be inserted into the inward opening 3d from the inside, etc. Since there are various situations where it is required to insert a member into the adjacent inner opening or outward opening from the inside or outside, the back support structure of the present invention can be extremely useful in those cases.

The specific configuration of each unit is not limited to the above-described embodiment,
Various modifications can be made without departing from the spirit of the present invention.

For example, as shown in FIG. 16, the main body C may be configured by welding a flat plate upper wall c <b> 2 and a bottom wall c <b> 3 to a vertical plate c <b> 1 made of a sheet metal material having irregularities alternately on the inner side and the outer side. The back support has a substantially U-shaped cross section in almost the entire region, and the inner openings k1 and k2 are integrally formed at the inwardly U-shaped portion, and the outer opening k3 is integrally formed at the outwardly U-shaped portion. The bag 103 can be configured effectively.

In this case, when it is necessary to form the bearing portion c4 and the like, it is only necessary to weld the bearing portion c4 and the like to the upper wall c2 and the like, so that it is possible to effectively realize the same structure as the above embodiment.

The side view which shows the chair which concerns on one Embodiment of this invention. The rear view. The rear perspective view. The perspective view which shows the mechanism part of the embodiment. The exploded view of FIG. The perspective view which looked at the back support rod of the embodiment from the inside. The perspective view which looked at the back support rod of the embodiment from the outside. Sectional drawing of the principal part of the same back support. The figure explaining the opening direction of the opening part with respect to the same back support. The partial expansion perspective view which shows the back support rod attaching part of the embodiment. The partial expansion perspective view which shows the groove structure of the back frame which concerns on the embodiment in a headrest part. Sectional drawing corresponding to FIG. The figure which shows the attachment structure to the back lower side part of the tension material in the embodiment. The rear view of the chair of the state which attached the optional member. The principal part enlarged view. The figure which shows the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Base part 3 ... Back support 3c ... Main-body part 3d, 3f ... Inner opening part 3d1, 3e1 ... Female thread part 3e ... Outer opening part 5 ... Back 31 ... Inner wall 32 ... Outer wall 33 ... Upper wall 34 ... Bottom wall

Claims (12)

It is formed by attaching a pair of back support rods that support the back to the left and right sides of the base,
The back support rod has a substantially U-shaped cross section at least over the entire body, and the inner opening is integrated into the inwardly U-shaped part and the outer opening is integrated into the outwardly U-shaped part. A chair characterized in that it is formed in. The chair according to claim 1, wherein the main body portion has a substantially rectangular parallelepiped shape and is mainly configured from a surface extending linearly with respect to the longitudinal direction. The chair according to claim 1 or 2, wherein an inner opening and an outer opening are alternately formed along the longitudinal direction. 4. The chair according to claim 3, wherein the outer wall of the back support rod is positioned as a back standing wall inside the inner opening, and the inner wall of the back support rod is positioned as a back standing wall inside the outer opening. The chair according to claim 4, wherein a female thread portion is formed in the opening portion using the rear standing wall. A partition is provided between the openings, the upper and lower portions of the partition are connected by the upper wall and the bottom wall of the back support rod, respectively, and the inner periphery is completely closed in the opening partitioned by the pair of partitions. The chair according to claim 1, which is in a stale state. The chair according to claim 1, wherein the inner periphery of the inner opening has a tapered shape that gradually reduces the opening toward the outside, and the inner periphery of the outer opening gradually decreases in the opening toward the inside. . The chair according to claim 7, wherein the tapered shape of the inner periphery also serves as a punching taper at the time of molding. The chair according to any one of claims 1 to 8, wherein the back support rod is formed of a molded body having an equal thickness in substantially the entire region. The chair according to any one of claims 1 to 9, wherein at least an inner opening located on the extended end side functions as a back attachment portion, and an outer opening located at an adjacent position functions as an elbow attachment portion. The chair according to claim 10, wherein the distance between the pair of back supports is widened from the base end portion toward the tip end portion, whereas the opening portion is open in a direction parallel to the spine width direction. The chair according to any one of claims 1 to 11, which is provided to support the back on both left and right side portions of the base portion, has an inner opening portion and an outer opening portion, and has a longitudinal direction and an opening direction. A back support rod having a substantially U-shaped cross section at each opening.

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