Chair

Abstract

To achieve both beauty and strength in a chair whose wooden backrest is fixed to a metallic back support member.SOLUTION: A backrest 3 is wooden, and has its rear face simply spreading without any protrusions or swells in a simple mode. A mounting hole 19 opens on the rear face of the backrest 3, and the backrest 3 is fixed to a front-facing boss body 22 of a back support member 10 via a joint member 18 inserted into the mounting hole 19. The joint member 18 is fixed to an anchor nut 20 embedded in the mounting hole 19 by means of an inner screw 21. The protruding portion 18b and front-facing boss body 22 of the joint member 18 are covered with a resin cover 24. As a result of the joint member 18 being engaged with the backrest 3 and fastened firmly to the backrest 3, the rear face of the backrest 3 can be made a simple single surface and the support strength by the back support member 10 can be secured.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a chair with a wooden backrest. [Background technology]

[0002] Chair structures are extremely diverse and can be classified according to various criteria, one of which is whether or not they have a reclining function, and another is the material of the components. There are various reclining structures, and the applicant of this application has disclosed one example in Patent Document 1. In Patent Document 1, a semicircular upper support frame that surrounds the user from the left, right, and rear is connected to the upper ends of side supports (pillars) erected on the outside of the left and right sides of the seat so that it can be tilted backward, and further, a backrest is connected to the upper support frame so that it can be tilted backward.

[0003] Therefore, in Patent Document 1, the backrest can be tilted backward in two stages. The backrest in Patent Document 1 is constructed by covering a synthetic resin backrest (inner shell) with cushioning material, and the entire backrest is covered with a skin. This chair has a simple appearance and a reclining function, so it can provide a high level of satisfaction to users.

[0004] On the other hand, when it comes to classification by material, chairs are generally divided into wooden and non-wooden ones. However, the definition of "wooden" is not always clear, and there are cases where the entire chair is made of wood and cases where only some parts such as the backrest and seat are made of wood. Wooden chairs have been around as long as human history, and there are a wide variety of grades. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-36949 Summary of the Invention [Problem to be solved by the invention]

[0006] Chairs are purchased based on a variety of factors, including function, use, design, price, and personal preference, but a major factor motivating purchases of wooden chairs is the preference for the texture and natural warmth of wood. In addition, there is a demand for promoting the use of wood, a natural resource, due to the need to reduce environmental impact and achieve carbon neutrality. Patent Document 1 discloses that the stick legs of a reclining chair are covered with a wooden tubular cover, which can be said to be part of responding to users' preference for wood.

[0007] As mentioned above, wooden chairs are the origin of chairs, and they come in a variety of shapes and grades, from high-end items that are considered art and crafts to popular items for dining, but it cannot be denied that chairs made entirely of wood are limited in function and places of use. Therefore, while some users have a preference for wood, there are also those who choose chairs made of steel or synthetic resin. In particular, for chairs used in offices and stores, it is estimated that there is a latent demand for chairs with metal frames and wooden backrests and seats.

[0008] In this sense, by using wood for a visible component such as the backrest and combining it with steel or synthetic resin parts, it is possible to satisfy both the wood-oriented and functional-oriented needs of users, and this can be understood to expand the variety of chairs in response to users' potential needs. For example, by using wood for the backrest and seat of the chair disclosed in Patent Document 1, it can be understood to be possible to meet users' potential needs.

[0009] The problem with using wood for the backrest is that wood is inferior in strength and workability to steel or synthetic resin, and therefore it is necessary to ensure strength and aesthetics while taking into consideration the material quality of wood. In other words, there is a demand for technology that can improve the aesthetics of chairs with wooden backrests while maintaining the necessary strength.

[0010] The present invention is intended to meet such demands. [Means for solving the problem]

[0011] The present invention includes many configurations, which are specified in each claim. The chair of the invention in claim 1 is as follows: "The seat has a wooden backrest and a hard material back support member disposed behind the backrest, A chair in which the backrest is fixed to a forward boss body provided on the back support member, An attachment hole concentric with the forward boss body is opened on the rear surface of the backrest, and the forward boss body is fixed to a coupling member inserted and fixed into the attachment hole. The back frame is made of a hard material such as metal or synthetic resin.

[0012] The invention of claim 2 is an example of the development of claim 1. "The joint member is formed in a cylindrical shape into which the forward boss body is inserted from the rear and which has a bottom plate at the front end, and the bottom plate is fixed to the backrest with a screw, Furthermore, the joint member has a protruding portion exposed to the rear of the backrest, and the protruding portion is fixed to the forward boss body by an inner screw. The structure is as follows.

[0013] The invention of claim 3 is an example of the development of claim 2, "A countersunk nut is embedded in the bottom of the mounting hole, and the inner screw that secures the bottom plate of the joint member is screwed into the countersunk nut." The structure is as follows.

[0014] The invention of claim 4 is an example of developing any one of claims 1 to 3, and the joint member is also fixed to the mounting hole by an adhesive.

[0015] The invention of claim 5 is also an example of the development of claim 2 or 3. "A cover is provided to cover the protruding portion of the coupling member and the exposed portion of the forward boss body, and the cover and the coupling member are fastened together with an outer screw that is screwed into the forward boss body from below." The structure is as follows.

[0016] The invention of claim 6 is an example of the development of claim 5. "A hole is formed on the rear surface of the backrest into which the front end of the cover can be inserted." The structure is as follows.

[0017] The invention of claim 7 is an example of the development of claim 1 or 2, "The backrest is shaped to bulge at least backward when viewed in a vertical cross-sectional view so that the thickest part is located midway between the upper end and the lower end." The structure is as follows.

[0018] The invention of claim 8 is an example of the development of claim 7. "The front surface of the backrest is also formed into a curved surface that bulges forward when viewed from the longitudinal side." The structure is as follows. Effect of the Invention

[0019] As a means for supporting the backrest with the back support member, for example, a wide bracket plate can be fixed to the front of the back support member by welding, and this bracket plate can be fixed to the back of the backrest with screws, but in this case, the wide bracket plate is exposed, which is not aesthetically pleasing. In this regard, it is possible to cover the bracket plate with a resin cover, but doing so reduces the exposed area of ​​the backrest's back, which reduces the significance of making the backrest out of wood, and the sense of incongruity caused by the prominent synthetic resin cover cannot be eliminated.

[0020] In contrast, in the present invention, the joint member is inserted into the thick part of the backrest, so the joint member can be made smaller while still ensuring the fixing strength between the backrest and the back support member. As a result, the exposure of the attachment members such as the joint member can be suppressed as much as possible, improving the aesthetics. In other words, the aesthetics of the wooden backrest can be maximized while the high support strength of the metal back support member can be ensured.

[0021] In addition, when using a bracket plate to support the backrest with the back support member, it is common to weld the bracket plate to the frame material, but the back support member is too close to the backrest, which does not necessarily look good. In contrast, the present invention attaches the backrest to a forward-facing boss body provided on the back support member, so a suitable gap is provided between the back support member and the backrest, achieving a neat design.

[0022] Since the joint member is inserted into the thick part of the backrest, the support strength of the backrest can be ensured without partially protruding the rear surface (back face) of the backrest, and the rear surface of the backrest can be kept with a simple profile while narrowing the gap between the backrest and the back support member as much as possible. This improves the exposure of the rear surface of the backrest, giving it a clean look, while maintaining an appropriate gap between the backrest and the back support member to ensure both support strength and aesthetic appeal.

[0023] In the configuration of claim 2, the joint member is in close contact with the inner surface of the mounting hole, so the fixing strength is high, and the forward boss body is fixed to the protruding part of the joint member, so the assembly work is easy. Another advantage is that the joint member has a bottom and is therefore strong.

[0024] In claim 2, it is possible to fix the bottom plate of the joint member to the backrest with wood screws, but using a countersunk nut as in claim 3 is preferable because it improves the fixing strength of the joint member to the backrest. If the joint member is fixed to the mounting hole with an adhesive as in claim 4, the fixing strength of the joint member can be further improved and loosening of the screw with use can be prevented.

[0025] If the protruding portion of the joint member is covered as in claim 5, the aesthetic appearance can be improved without applying cosmetic treatment such as plating to the joint member. When a cover is provided in this way, it is expected that the front edge of the cover will be pushed against the rear surface of the backrest due to assembly errors, making installation difficult. However, if a relief hole is formed on the rear surface of the backrest as in claim 6, the relief hole can absorb processing errors and assembly errors, improving the ease of assembly.

[0026] The backrest can be formed to have a substantially uniform thickness over its entire height, but by forming at least the rear surface to bulge backward as in claim 7, the mounting hole area can be thickened to ensure the required depth for the mounting hole. Since the rear surface of the backrest is bulging overall, it does not feel strange and does not impair the aesthetic appearance. Therefore, the support strength of the backrest can be improved without impairing the aesthetic appearance.

[0027] If the front surface of the backrest is curved forward as in claim 8, when a person leans against the backrest and arches his / her back, there is no feeling of tension on the back, which is excellent in comfort. In addition, the lumbar support function is exerted, which has the advantage that the person can work on a computer or other tasks with their back straight. [Brief description of the drawings]

[0028] [Figure 1] 1A and 1B are diagrams showing the appearance of an embodiment, in which (A) is a perspective view seen from the front, (B) is a perspective view seen from the rear, (C) is a plan view, and (D) is a side view showing the before and after reclining positions. [Diagram 2]1A is an exploded perspective view of a main portion, and FIG. 1B is an exploded perspective view of a state in which a back support member is facing upward. [Diagram 3] 1(A) is a cross-sectional view taken along line AA in FIG. 1(C), and FIG. 1(B) is a cross-sectional view taken along line BB in FIG. 1(C). [Figure 4] 1A is an exploded side view of the seat, and FIG. 1B is an exploded perspective view of the seat. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Next, an embodiment of the present invention will be described with reference to the drawings. In the following, the terms front, back, left and right are used to specify directions, but these directions are based on the state seen from a person normally seated in a chair. The front viewing direction is the direction facing the seated person.

[0030] (1) Overview of the chair First, an overview of the chair will be described. This embodiment has an appearance and function similar to the chair disclosed as an embodiment in Patent Document 1. As shown in FIG. 1(A), the chair has a leg device 1, a seat 2, and a backrest 3 as basic elements. The leg device 1 has a structure in which a leg column 4 made of a gas cylinder is erected at the center of a grounding body having multiple (three or more) leg blades, and casters are provided at the tip of each arm. Therefore, this embodiment is applied to a swivel chair. The grounding body can also be in a form in which rings are fixed to the tips of multiple arms extending radially from a cylindrical body. The seat 2 and the backrest 3 are made of wood.

[0031] As shown in Fig. 4, a base 5 having a substantially rectangular shape when viewed from the bottom (and in a plan view) is fixed to the upper end of the leg column 4. A seat support member 6 is attached to the base 5 so as to be able to slide back and forth, and the seat 2 is attached to the upper surface of the seat support member 6. The seat support member 6 is biased in the backward direction by a spring 7. The base 5 is, for example, an aluminum die-cast product, the seat support member 6 is, for example, a molded product of synthetic resin, and the seat 2 is made of wood.

[0032] The chair is equipped with a back support frame 8 that is U-shaped in plan view and surrounds the seated person from behind at a position higher than the seat 2. The back support frame 8 therefore has left and right side parts 9 located on the left and right sides of the seated person (and the backrest 3) and a rear part (left and right long parts) 10 located behind the seated person (and the backrest 3), and the backrest 3 is connected to the rear part 10. Therefore, in this embodiment, the rear part 10 of the back support frame 8 serves as a back support member as described in the claims. The side parts 9 of the back support frame 8 are connected to side supports 11 arranged on the left and right sides of the seat 2 so as to be able to tilt backward.

[0033] The side support 11 is, for example, an aluminum die-cast product, and has a vertically long, plate-like support portion 12 and a front-rear long, substantially circular upper horizontal portion 13 formed integrally with the upper end of the support portion 12. Then, as shown in Fig. 2, for example, a boss body 14 with its rear end exposed rearward is connected to the upper horizontal portion 13 so as to be able to tilt rearward, and the front end of a steel pipe back support frame 8 is fitted into the boss body 14 from behind and fixed thereto by welding or the like.

[0034] A cavity that opens toward the rear is formed in the upper horizontal portion 13 of the side support 11, and the boss body 14 is connected to the inside of the cavity so as to be able to tilt backward, and an elastic body that provides resistance to the backward tilt of the boss body 14 is built into the cavity. Therefore, the backrest 3 tilts backward with the rear part of the upper horizontal portion 13 of the side support 11 as a fulcrum, as shown in Fig. 1(D). Also, when a seated person leans against the backrest 3, the seated person's buttocks tend to move forward, so that the seat 2 moves forward against the spring 7.

[0035] A base 12a that wraps around underneath the seat 2 is integrally formed at the lower end of the support 12 in the side support 11, and the tip of the base 12a is fitted into an engagement hole 15 (see Figures 1(D) and 3) formed in the base 5, and the tip is fixed to the base 5 with a bolt.

[0036] As described above, the leg pillar 4 is made of a gas cylinder, and when the lock of the gas cylinder is released, the height of the seat 2 and the backrest 3 can be freely adjusted. As shown in Figures 1(A) to (C), a knob 16 for releasing the lock of the gas cylinder is attached to the upper horizontal part 13 of the right side support 11 so as to be rotatable about the axis of the upper horizontal part 13.

[0037] For example, as shown in Fig. 1, the backrest 3 is curved in a shape that bulges backward (concave forward) in a plan view so as to embrace the body of a seated person from behind, and the rear portion 10 of the backrest frame 8 is curved to follow the curvature of the backrest 3. Therefore, both the front surface (front side) and the rear surface (rear side) are curved. As shown in Fig. 2, there is a certain amount of gap between the rear portion 10 of the backrest frame 8 and the backrest 3. Moreover, the backrest frame 8 is generally in a horizontal position.

[0038] (2) Backrest connection structure Next, the connection structure of the backrest 3 to the rear portion 10 of the back support frame 8 will be described mainly with reference to FIGS.

[0039] The backrest 3 is a machined product made from laminated wood or solid wood blocks, and as shown in Figure 3(A), the front side is gently curved forward and bulges backward, with the thickest part located below the middle part. Therefore, it is bulging downward when viewed from the vertical section. When not leaning on it (in its free state, i.e. in its reference state), the backrest 3 is tilted backward at a gentle angle (for example, about 10°) with respect to the vertical line.

[0040] Two locations (generally the thickest locations) on the rear surface of the backrest 3 that are located toward the left and right ends and toward the bottom are fixed to the rear portion 10 of the back support frame 8 via metal joint members 18. For example, as shown in FIG. 3(B), the joint member 18 is formed in a cylindrical shape that is open toward the rear and has a bottom plate 18a at the front end, and is inserted from behind into a mounting hole 19 formed in the backrest 3. A flanged eye nut 20 is embedded in the bottom surface of the mounting hole 19, and the bottom plate 18a of the joint member 18 is fixed to the bottom surface of the mounting hole 19 by an inner screw (inner bolt) 21 screwed into the eye nut 20.

[0041] The joint member 18 is also fixed to the mounting hole 19 by an adhesive such as an epoxy adhesive. The adhesive may be applied to the mounting hole 19 in advance, or may be applied to the joint member 18 in advance. When an adhesive is used, the clearance between the joint member 18 and the mounting hole 19 is filled, so that the joint member 18 can be made to have no play and the fixing strength can be significantly improved, and the inner screw 21 can also be prevented from loosening.

[0042] The joint member 18 has a protruding portion 18b exposed behind the backrest 3, while a forward boss body 22 that fits tightly from behind into the joint member 18 is fixed by welding to the rear portion 10 of the back support frame 8, and the forward boss body 22 and the joint member 18 are fixed by an outer screw (outer bolt) 23 that is inserted from below into the protruding portion 18b of the joint member 18. Therefore, the forward boss body 22 has tapped holes that are open at the top and bottom and into which the outer screws 23 are screwed.

[0043] The outer surface of the forward boss body 22 and the inner surface of the coupling member 18 are formed to have an oval cross section. Also, as shown in Fig. 3(B), for example, a stepped portion 18c is formed on both the upper and lower surfaces of the coupling member 18 onto which the cover 24 can be overlapped. Therefore, the coupling member 18 can be used without regard to the up-down direction.

[0044] Since the coupling part 18 has a perfect circle on the outer periphery and an oval shape on the inner periphery, it needs to be held in a specified position and fixed with inner screws 21. However, by using a single jig equipped with a holder part that fits into the stepped-down parts 18c of the left and right coupling parts 18, the coupling parts 18 can be held in a specified position and fixed.

[0045] Alternatively, it is possible to fix the joint member 18 to the mounting hole 19 with adhesive while fitting the joint member 18 into the forward boss body 22 of the back support frame 8, and then remove the back support frame 8 from the joint member 18 and fix it with the inner screw 21. In other words, it is also possible to use the back support frame 8 as a position adjustment jig for the joint member 18. There is an advantage in that such a work process of fixing using an adhesive is also possible.

[0046] The protruding portion 18b of the coupling member 18 and the forward boss body 22 are covered from all sides with a synthetic resin cover 24, and the cover 24 is fastened together with the coupling member 18 to the forward boss body 22 by the outer screw 23. Therefore, the lower part of the cover 24 is formed thicker than the height of the head of the outer screw 23, and a countersunk hole 25 into which the head 23a of the outer screw 23 fits is formed in this thick part. The cover 24 is set to a dimension that allows it to fit between the backrest 3 and the rear portion 10 without any gaps, and its diameter gradually narrows toward the rear (it gradually widens toward the front).

[0047] 8 as a modified example, it is also possible to form an escape hole (countersink hole) 26 into which the front end of the cover 24 can enter on the rear surface of the backrest 3. By forming the escape hole 26 in this way, even if the front-to-rear position of the cover 24 varies slightly due to an error in mounting the cover 24, the error can be absorbed and the fastening work with the outer screw 23 can be easily performed.

[0048] When the joint member 18 is fixed to the mounting hole 19 by adhesive, the adhesive that protrudes to the outside can be advantageously contained in the relief hole 26. In the drawing, a slight clearance is shown between the outer peripheral surface of the front end of the cover 24 and the inner peripheral surface of the relief hole 26, but it is also possible to fit the front end of the cover 24 tightly into the relief hole 26. The relief hole 26 is formed using an end mill that processes the eye nut 20. That is, the relief hole 26, which is circular in rear view, is processed by moving the end mill in three directions, X, Y and Z, while rotating it.

[0049] 3(B), the front end of the forward boss body 22 provided on the rear portion 10 extends into the mounting hole 19. Therefore, the backrest 3 is supported by the forward boss body 22 via the joint member 18. In this embodiment, the depth of the mounting hole 19 is approximately half the thickness of the backrest 3. The portion of the rear portion 10 of the back support frame 8 to which the forward boss body 22 is fixed is crushed into a D-shaped cross section, and the forward boss body 22 is welded to its front surface.

[0050] (3) Seat structure Just to be sure, we will also explain the structure of the seat. Seat 2 is made of wood, and is roughly a rounded rectangle in plan view, with the top surface carved out significantly to fit a person's buttocks. In other words, the top surface is concave with the deepest part 2a located toward the rear, and is also concave so that the middle left and right parts are deeper when viewed from the front in longitudinal section. The front top surface of seat 2 is gently curved, bulging upward while remaining almost horizontal. Therefore, the top surface (concave surface) of seat 2 forms a gentle sideways S-curve when viewed from the side in longitudinal section.

[0051] The underside of the seat 2 is formed with a storage recess 27 into which the seat support member 6 fits. The underside of the backrest 3 in front of the storage recess 27 is gently curved so that it becomes higher toward the front end. Therefore, the thickness of the front part of the seat 2 gradually decreases toward the front end. The underside of the seat 2 is slightly higher than the upper surface of the base 5.

[0052] For example, as shown in Fig. 4, the base 5 has a shallow tray shape that is generally rectangular in plan view and opens upward. As clearly shown in Fig. 7, a boss hole 28 into which the upper end of the leg 4 fits from below is formed in the approximate center of the base 5. In order to increase the height of the boss hole 28, a downward-facing cylindrical portion 5a (see Fig. 4) is formed in the base 5.

[0053] For example, as shown in FIG. 4, a push valve 29 for unlocking is protruded from the upper end of the leg column 4, and an unlocking device 30 for pushing the push valve 29 is disposed on the base 5. The push valve 29 is pushed by rotating the knob 16 described above.

[0054] As shown in Figures 4 and 5, the seat support member 6 is in the form of a plate, with a square opening formed in the center. Therefore, the seat support member 6 is formed in the shape of a square frame, with a number of reinforcing ribs extending vertically and horizontally formed on the upper surface. As shown in Figure 4(A), the seat support member 6 and the seat 2 are fixed at the four corners of the front, rear, left and right with screws 31. The screws 31 are screwed into countersunk nuts 31a (see Figures 4(B) and 5) embedded in the seat 2.

[0055] As already described, the seat receiving member 6 is mounted on the base 5 so as to be slidable back and forth. As a sliding means, as shown in Fig. 4, long holes 32 are formed in the left and right sides of the front of the seat receiving member 6, penetrating vertically in the front-rear direction, and a square guide body 33 is inserted into the long hole 32 and fixed to the base 5. The guide body 33 is formed with a flange 33a that holds the seat receiving member 6 facing upward so that it cannot be separated, and is fixed to the base 5 with a screw 34. Therefore, the base 5 is formed with a square receiving portion 35 that holds the guide body 33 so that it cannot be displaced, and a tapped hole is provided in the square receiving portion 35.

[0056] Furthermore, as shown in Figure 4(B), for example, a pair of bearing pieces 36 are protruding downward at two locations on either side of the opening at the rear of the seat support member 6, one on each side. Meanwhile, as only slightly shown in Figure 4, a front-to-rear elongated support rib 37 is formed in the base 5 and is sandwiched between the pair of bearing pieces 36, and a front-to-rear elongated guide hole 38 is formed in the support rib 37. A left-to-right slide pin (not shown) is inserted into the pair of bearing pieces 36 and the guide hole 38 from the opening side via a bush 39, only slightly shown in Figure 4(B).

[0057] Therefore, the rear part of the seat receiving member 6 is connected to the base 5 so as to be slidable back and forth. The slide pin is prevented from coming off by a stopper plate 40 shown in Fig. 4. The stopper plate 40 is press-fitted into an engagement hole 41 (see Figs. 5 and 6) formed on the underside of the seat 2.

[0058] As shown in Fig. 4, a pair of left and right roller receiving recesses 42 that open upward are formed in the front part of the base 5, and rollers 43 with their axes extending in the left and right directions are rotatably arranged in the roller receiving recesses 42, and the seat receiving member 6 is supported by the left and right rollers 43. A reinforcing plate (not shown) made of metal or the like that abuts against the rollers 43 from above is attached to a recess 44 (see Fig. 5) formed in the underside of the seat receiving member 6.

[0059] As shown in Fig. 4, a front-rear elongated spring (compression coil spring) 7 is disposed in a front portion of the base 5 as an elastic body that provides elastic resistance to the forward movement of the seat support member 6. The spring 7 is disposed in a spring support recess 45 formed in the base 5, and as can be seen from Fig. 7, the front end is supported so as not to shift by a front spring support portion 46 provided in the spring support recess 45, and the rear end is supported so as not to shift by a rear spring support 47 provided in the seat support member 6.

[0060] 7, the front-to-rear length of the seat support member 6 is greater than that of the base 5, and while the seat 2 and seat support member 6 are not moving forward, the front end of the seat support member 6 is at approximately the same position as the front end of the base 5, while the rear end of the seat support member 6 protrudes rearward a certain distance from the rear end of the base 5. Therefore, the seat support member 6 can move forward and backward a certain distance while overlapping (close to) the upper surface of the base 5. Also, because the guide holes 38 etc. are inclined, the seat 2 moves forward while rising slightly.

[0061] As shown in FIG. 6, in the storage recess 27 of the seat 2, there are provided downwardly protruding one rectangular front boss body 49 elongated on the left and right sides, left and right intermediate boss bodies 50 located behind the front boss body 49, left and right outside boss bodies 52 located on the left and right sides outside the front boss body 49, and left and right rear boss bodies 53 located further rearward.

[0062] On the other hand, the seat receiving member 6 is formed with an intermediate boss receiving body 54 on which the intermediate boss body 50 is placed, an inside receiving body 55 on which the inside boss body 51 is placed, an outside boss receiving body 56 on which the outside boss body 52 is placed, and a rear boss receiving body 57 into which the rear boss body 53 is fitted. The front boss body 49 is fitted from above into the frame portion of the seat receiving member 6 in which the rear spring receiving body 47 is formed.

[0063] (4) Summary In this embodiment, the backrest 3 (and seat 2) is made of wood, which brings out the warmth of wood and gives the chair an unprecedented aesthetic feel, even though it is a reclining chair. That is, the rear surface of the backrest 3 is a gently curved surface, but the curved surface spreads across the entire chair as a single surface, with the cover 24 only partially exposed, giving the chair a simple appearance, fully bringing out the warmth of wood and creating an unprecedented, streamlined appearance.

[0064] More specifically, the backrest 3 is fixed to the rear section 10 via the joint member 18, but since the joint member 18 extends inside the backrest 3 and has a small area when viewed from the rear, the area of ​​the cover 24 is not large either, and therefore the cover 24 has a simple appearance in which it is not conspicuous, and the texture of the wood that constitutes the backrest 3 is strongly emphasized. This realizes a design that highlights the texture of the wood while providing a functional chair with the back support frame 8 and other parts made of metal.

[0065] As a means for fixing the forward-facing boss body 22 to the rear portion 10, it is possible to weld the forward-facing boss body 22 to the inner peripheral edge of a hole drilled in the rear portion 10, but it is preferable to crush the rear portion 10 into a D-shaped cross section as in the embodiment and weld the forward-facing boss body 22 to it, as this prevents a decrease in the strength of the back support frame 8.

[0066] Furthermore, when the forward boss body 22 is inserted into the mounting hole 19 as in the embodiment, the gap between the backrest 3 and the rear portion 10 is reduced as much as possible, and the forward boss body 22 directly supports the backrest 3, thereby preventing a large moment from acting on the base of the forward boss body 22 and improving the supporting strength of the backrest 3.

[0067] Furthermore, by providing the countersunk holes 25 on the underside of the cover 24 as in the embodiment, the outer screws 23 cannot be seen from the rear view, which is aesthetically pleasing. Also, there is no discomfort when a person places their fingertips on the underside of the cover 24.

[0068] As shown in Fig. 3(A), in this embodiment, the degree of curvature of the rear surface of the upper and lower parts of the backrest 3 is larger (the radius of curvature is smaller) than other parts, and by configuring it in this way, it is possible to maximize the fit of the body against the front surface while forming the backrest 3 into a cross-sectional shape that bulges forward and backward to provide an appropriate thickness. Therefore, it is possible to provide the backrest 3 with the necessary strength while presenting a natural appearance.

[0069] Regarding the seat 2, if the underside of the front part is curved to bulge downward as in the embodiment, it presents a natural appearance, looks good, and is easy to process. If the upper surface of the seat 2 is formed with an S-shaped cross section as in the embodiment and the deepest part 2a is positioned at the rear, slippage between the seat sitter's body and the seat 2 is eliminated, and the seat 2 can be moved forward precisely when reclining.

[0070] Wooden seats made by bending plywood are widely used, but in this case, the overall thickness is uniform, so the profile of the upper and lower surfaces cannot be changed, and complex three-dimensional processing is not possible. Therefore, there is no freedom in design and design, but the seat 2 of this embodiment is made by cutting out wood, so the thickness varies in various places, making it possible to realize a three-dimensional curved surface that fits well and has an excellent aesthetic feel.

[0071] Although the illustrated embodiment has been described above, the present invention can be embodied in various other ways. For example, the side support body as in the embodiment is not essential, and for example, the upper end of one back support column can be fixed to the left and right middle part of a horizontal back support member that is long on the left and right, and the back support member and the back support column can form a T-shape. Alternatively, the left and right ends of the back support member can be fixed to the upper ends of two back supports, and the back support member and the left and right back supports can form a U-shape when viewed from the rear.

[0072] It is also possible to form the forward boss body into a cylindrical shape and form the joint member as a solid body. It is also possible to form only one mounting hole in the middle of the left and right of the backrest and support the backrest with one joint member. It is also possible to form a male thread on the outer periphery of the joint member and screw the joint member into the mounting hole. In this case, no eye nut is required. The present invention can also be embodied in chairs other than swivel chairs, such as those with rod-legged leg devices.

[0073] Furthermore, the backrest can be connected to the back frame so that it can be tilted backward. For example, in the embodiment, since the lower part of the backrest is thick, it is possible to form a space in the thick part of the backrest by connecting it to the mounting hole, and to place the rotation mechanism member in the deep part of the space. Alternatively, it is possible to connect the forward boss body to the rear part so that it can rotate against the elastic body. [Industrial Applicability]

[0074] The present invention can be embodied in a chair, and therefore has industrial applicability. [Explanation of symbols]

[0075] 1 leg device 2nd seat 3. Backrest 5. Bass 6 Seat support material 8 Back support frame 9 Side section 10 Rear section (back support member) 11 Side support 12 Support section 13 Upper horizontal part 14. Backward tilting boss body 18 Joint members 19 Mounting holes 20 Onime Nut 21 Inner screw 22 Forward-facing boss body 23 Outer screw 24 Cover 25 Countersink 26 Relief hole

Claims

1. The seat has a wooden backrest and a hard material back support member disposed behind the backrest, A chair in which the backrest is fixed to a forward boss body provided on the back support member, A mounting hole is opened on the rear surface of the backrest, the mounting hole being concentric with the forward boss body, and the forward boss body is fixed to a coupling member inserted and fixed into the mounting hole. chair.

2. The joint member is formed in a cylindrical shape into which the forward boss body is fitted from the rear and which has a bottom plate at its front end, and the bottom plate is fixed to the backrest with a screw, The joint member has a protruding portion exposed to the rear of the backrest, and the protruding portion is fixed to the forward boss body by an inner screw.

2. The chair according to claim 1.

3. A countersunk nut is embedded in the bottom surface of the mounting hole, and an inner screw for fixing the bottom plate of the joint member is screwed into the countersunk nut. A chair as claimed in claim 2.

4. The joint member is also fixed to the mounting hole by an adhesive. A chair according to any one of claims 1 to 3.

5. A cover is provided to cover the protruding portion of the coupling member and the exposed portion of the forward boss body, and the cover and the coupling member are fastened together by an outer screw screwed into the forward boss body from below. A chair as claimed in claim 2 or 3.

6. A relief hole into which the front end of the cover can be fitted is formed on the rear surface of the backrest. A chair as claimed in claim 5.

7. The backrest is shaped to bulge at least backward in a vertical cross-sectional view so that the thickest part is located at a mid-height portion between the upper end and the lower end. A chair as claimed in claim 1 or 2.

8. The front surface of the backrest is also formed into a curved surface that bulges forward when viewed from the vertical section. A chair as claimed in claim 7.

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