Body support unit of chair and method for manufacturing same

Abstract

Provided is a body support unit in which a three-dimensional net-like body made of resin fibers is used as a cushion material and contact with a user's body is soft. This body support unit is, for example, a seat 2, and the seat 2 has a seat inner shell 12, a cushion material 13, and an upholstery 14. The cushion material 13 is configured from a base material layer 15 comprising a highly elastic three-dimensional net-like body and a surface layer 16 comprising a vertical nonwoven fabric such as a felt material. The surface layer 16 is thinner than the base material layer 15 and is covered by the upholstery 14. The surface layer 16 directly overlaps the base material layer 15. A pressure receiving surface of the seat inner shell 12 has a three-dimensional shape emulating a user's body but, because the base material layer 15 is press worked, fittability to the body is high even if the material is firm. Since the materials of the base material layer 15 and the surface layer 16 are commercially available sheet materials of a uniform thickness, the cost is reduced. An outer peripheral part 16a of the surface layer 16 covers the outer peripheral surface of the base material layer 15. Therefore, contact with a body is soft and the appearance is good.

Description

Body support unit for chair and method for manufacturing the same

[0001] The present invention relates to a body support unit having a structure in which a cushioning material is covered with a covering material like a seat or a backrest of a chair, and a method for manufacturing the same. Here, the body support unit includes, as representative examples of the above-mentioned back and seat, a headrest, a shoulder rest, an elbow pad, and the like.

[0002] Now, although foamed urethane is widely used as a cushioning material for a seat or a backrest of a chair, foamed urethane has problems such as poor air permeability, not necessarily high elastic force, and a tendency to occur sagging in which the elastic restoring force decreases during use.

[0003] On the other hand, there exists a three-dimensional network structure in which resin fibers rich in elasticity are intertwined and bonded. This three-dimensional network structure is excellent in air permeability, has a high repulsive force, and is also excellent in durability. By selecting the thickness and density of the fibers, a considerably soft feeling can also be realized. Focusing on this point, Patent Document 1 discloses that a cushioning material made of a three-dimensional network body is composed of a tough base layer made of thick fibers and a soft surface layer in which thin fibers are densely intertwined, and a two-layer structure in which both are integrally heat-sealed.

[0004] Patent Document 2 discloses a cushioning material having a structure including a three-dimensional network body and a vertical non-woven fabric, but the support structure and covering structure of the cushioning material are unclear.

[0005] Japanese Patent Application Laid-Open No. 2025-34936 International Publication WO2021 / 177226

[0006] A three-dimensional network body made of highly elastic resin fibers is widely used for mattresses and the like. And, as in Patent Document 1, when the surface layer is composed of thin fibers, the feeling can be softened, but it is currently difficult to achieve the softness like a urethane cushion. On the other hand, although it can be said that a soft touch can be realized by using a vertical non-woven fabric as the surface layer as in Patent Document 2, when the cushioning material is configured in a laminated structure of different materials, problems related to assembly work and problems such as interlayer slippage are likely to appear.

[0007] The present invention was made to improve this situation. Furthermore, although the present application discloses many novel structures, these structures can be claimed as independent or dependent claims.

[0008] This invention focuses on a body support unit for a chair. While the seat and backrest are typical components of a body support unit, the seat is particularly preferred. This is because the seat is subjected to heavy loads repeatedly and also requires a certain level of softness.

[0009] The chair body support unit of the present invention has the following configuration: "It comprises a shell member made of synthetic resin with one side being a pressure-receiving surface, a cushioning material overlapping the pressure-receiving surface of the shell member, and upholstery covering the cushioning material, wherein the cushioning material includes a base layer made of a three-dimensional mesh formed by bonding together a group of curved synthetic resin elastic fibers, and a surface layer made of a nonwoven fabric, felt, or knitted fabric having a group of fibers extending in the thickness direction, and the surface layer directly overlaps the base layer."

[0010] In the chair body support unit of the present invention, the surface layer is directly superimposed on the base layer, resulting in a simple structure and easy assembly of the unit. Furthermore, because nonwoven fabric, felt, or knitted fabric is soft against the body, even elements that come into strong contact with the body, such as a seat, can achieve a soft feel similar to that of a urethane cushion.

[0011] The present invention includes a method for manufacturing a body support unit for a chair, and this method first has the following configuration: "The steps include: preparing a shell member made of synthetic resin having one side as a pressure-receiving surface that is not flat; preparing a cushioning material to overlap the pressure-receiving surface; preparing upholstery to cover the cushioning material; and placing the cushioning material on the shell member and then attaching the upholstery."

[0012] Furthermore, in addition to the above configuration, the following configuration is included: "The step of preparing the cushioning material comprises the steps of preparing a base layer consisting of a three-dimensional mesh formed by intertwining a group of curved synthetic resin elastic fibers, and preparing a surface layer consisting of a nonwoven fabric, felt, or knitted fabric having a group of fibers extending in the thickness direction, and the step of preparing the base layer comprises the steps of preparing a sheet-like material of equal thickness and processing the material into a three-dimensional shape by heating and pressing it."

[0013] The present invention provides a method for manufacturing a body support unit for a chair, which allows for the use of a sheet-like material of uniform thickness to provide a body support unit with a high degree of fit.

[0014] According to the inventions of this application, it is possible to achieve both a soft tactile feel and ease of assembly.

[0015] [Correction based on Rule 91 16.01.2026] This is a diagram of a chair with a seat according to the first embodiment, where (A) is a perspective view from the front, (B) is a side view, and (C) is a perspective view from the rear and below. (A) is a separated perspective view of the chair from the front, (B) is a separated perspective view of the chair from the rear, and (C) is a perspective view of the seat from the rear and above. (A) is a downward perspective view of the seat, and (B) is a bottom view of the seat. This is a separated perspective view of the seat from above. This is a separated perspective view of the seat from below. (A) is a longitudinal front view at the retractable section, a VIA-VIA cross-sectional view of Figure 1(A), (B) is a B-B cross-sectional view of (A), (C) and (D) are longitudinal front views showing parts of the manufacturing process, respectively, and (E) is a plan view of (D). This is a separated perspective view of the second embodiment from above. This is a separated perspective view of the second embodiment from below. The diagram shows the processing of the base layer, with (A) being a plan view and (B) being a side view. This is a bottom view of the base. (A) is a cross-sectional view taken along A-A in Figure 10, (B) is a cross-sectional view taken along B-B in Figure 10, (C) is an unfolded view of the surface layer, and (D) is a bottom view after three-dimensionalization.

[0016] Next, embodiments of the present invention will be described based on the drawings. This embodiment is applied to the seat of a swivel rocking chair, which is commonly used for office work. In this application, terms such as "front and back" and "left and right" are used to specify directions, but these are based on the orientation of a person sitting in a normal posture. A front view is the direction opposite to the person sitting.

[0017] (1) Basic structure of the chair As can be understood from diagram 1, the chair to which this embodiment is applied is a swivel chair that is widely used in offices, and the chair is equipped with a leg assembly 1, a seat 2, and a backrest 3 as basic elements. The backrest 3 is made of an elastomer-type synthetic resin plate with numerous perforations. The leg assembly 1 has a structure in which a leg support column 4 made of a gas cylinder is erected in the center of a base which has five leg wings, and casters are provided at the tip of each leg wing.

[0018] A base 5 is fixed to the upper end of the leg support 4, and a second tilting frame 7 is connected to the base 5 via left and right first tilting frames 6, and a backrest 3 is attached to the second tilting frame 7. A seat support mechanism is attached to the base 5 to move the seat 2 backward and tilt it backward in conjunction with the backward tilting of the backrest 3, and a seat outer shell (seat support shell body) 8 is fixed to the seat support mechanism, and the seat 2 is fixed to the outer shell 8.

[0019] The second tilting frame 7 has a back support column 9 located in the middle of the left and right sides and extending vertically, and lower side portions 10 located at the bottom and extending horizontally. The lower side portions 10 become higher and narrower towards the tip, forming an overall crescent shape. Therefore, the second tilting frame 7 as a whole has a shape similar to an anchor. A swing arm 11 is attached to the back support column 9, and the upper ends of the backrest 3 are fixed to both the left and right ends of the swing arm 11, and the lower corners of the backrest 3 are fixed to the tips of the lower side portions 10.

[0020] (2) Basic structure of the seat As shown in Figure 5, the seat 2 comprises a synthetic resin seat inner shell (seat plate) 12, a cushioning material 13 placed on top of it, and upholstery (surface material) 14 covering the cushioning material 13 from above. The cushioning material 13 has a two-layer structure consisting of a base layer 15 and a surface layer (buffering layer) 16 placed on top of it. The seat inner shell 12 is an example of a shell member. The total thickness of the cushioning material 13 is about 35 to 40 mm, of which the thickness of the base layer 15 is about 30 to 35 mm and the thickness of the surface layer 16 is about 5 to 10 mm. The surface layer 16 consists of a nonwoven fabric, felt, or knitted fabric as described above. Since felt is also a type of nonwoven fabric, a "nonwoven fabric or felt having a group of fibers extending in the thickness direction" can be called a "vertical nonwoven fabric". The base layer 15 consists of a three-dimensional mesh as described above. From the viewpoint of weldability, thermoplastic resin materials are preferred for the three-dimensional mesh structure; from the viewpoint of elasticity and resistance to repeated loads, polyester resin is preferred; and from the viewpoint of softness to the touch, elastomers are preferred. In this case, the fibers constituting the three-dimensional mesh structure include both a structure in which the entire structure is composed of elastomer material and a structure in which the core material is covered with an elastomer layer. Since the three-dimensional mesh structure is constructed by heat welding (fusion) numerous fibers at the contact points, a composition that allows heat welding at the lowest possible temperature is preferred. When the fibers are composed of a core material and a coating layer, it can be said that high elasticity and weldability can be easily achieved simultaneously by using a material with a low softening temperature for the coating layer. Furthermore, by using commercially available uniform-thickness sheets as the base layer 15 and the surface layer 16, manufacturing costs can be suppressed. In addition, the base layer 15 has high elastic strength and durability, but is formed into a three-dimensional shape to fit the user's body. This allows for accurate attachment to the shell member and ensures a good fit to the user's body. Because the shell member and base layer 15 are three-dimensional, and the surface layer 16 is soft and conforms to the base layer 15, it offers excellent body fit. Furthermore, by using commercially available materials (sheet material or block material) for the base layer 15, costs can be reduced. In addition, because the entire surface of the base layer 15 is covered with the surface layer 16, a soft feel can be achieved regardless of which part of the body support unit the person's body touches.Since the upholstery 14 overlaps the entire surface of the base layer 15 via the surface layer 16, covering the entire surface of the base layer 15 with the surface layer 16 allows the upholstery 14 to be held in a taut state by utilizing the softness of the surface layer 16. Therefore, it looks good. Furthermore, it is preferable that the base layer 15 is a single (one) piece. In this case, the base layer 15 is easy to handle and manufacturing becomes easier.

[0021] Furthermore, although the surface layer 16 is a sheet of uniform thickness, its high flexibility allows it to fit the base layer 15 even if the base layer has a three-dimensional shape. Therefore, integration with the base layer 15 is ensured, providing the user with a soft feel. In addition, because the surface layer 16 and base layer 15 have excellent breathability, if fabric is used as the upholstery 14, breathability is ensured for the entire body support unit, preventing stuffiness. Natural or artificial leather can also be used as the upholstery 14. In this case as well, the high heat dissipation of the base layer 15 reduces stuffiness.

[0022] The upholstery 14 can be woven or knitted. If breathability is not required, artificial or natural leather can also be used. The base layer 15 and surface layer 16 have high breathability, resulting in excellent heat dissipation. The cushioning material 13 of this embodiment has excellent durability and elasticity, so it is worth using even if the upholstery 14 is leather.

[0023] As shown in Figures 3 and 5, in this embodiment, the front part of the seat inner shell 12 has numerous horizontal slits and is a bending deformation allowable part 12a that can be rolled up and deformed. However, since the cushioning material 13 and upholstery 14 also bend and deform, the front part 2a of the seat 2 is also a bending deformation allowable part that can be rolled down. When the left and right brackets 17 that protrude downward from the front end of the seat inner shell 12 are pulled backward, the front part 2a of the seat 2 is rolled down. Even in this case, the integrity of the cushioning material is maintained, so the aesthetic appearance is not easily deteriorated. This makes it possible to adjust the front-to-back position of the front end of the seat 2. In other words, the depth of the seat 2 can be adjusted. Behind the bending deformation allowable part 12a of the seat inner shell 12, a sinking deformation allowable part 12b is formed, which has numerous vertically elongated and horizontally curved slits.

[0024] For example, as shown in Figure 3, a pair of downward-facing brackets 17 are integrally formed on the front end of the seat inner shell 12, while as shown in Figure 2(A), a slider 18 is mounted on the outer shell 8 so as to be able to move back and forth, and the downward-facing brackets 17 of the seat inner shell 12 are connected to the catch portion 18a at the front end of the slider 18. The slider 18 can be moved back and forth by operating the lever 19 shown in Figure 1(C). Therefore, by adjusting the front-to-back position of the lever 19, the front part 2a of the seat 2 can be rolled in and unrolled to adjust the depth of the seat 2.

[0025] As shown in Figure 3, the lower surface of the inner shell is provided with protrusions such as bosses 20 and connecting claws 21 that contact the outer shell. Also as shown in Figure 3, a large number of hook-shaped claws 22 for connecting the upholstery 14 are formed on the lower surface of the seat inner shell 12. The hook-shaped claws 22 are provided along the entire circumference of the outer edge of the seat inner shell 12 and at the rear of the bending deformation allowable portion 12a.

[0026] On the other hand, as shown in Figure 5, the upholstery 14 has a pocket portion 14a that wraps around the bending deformation allowable portion 12a of the seat inner shell 12 from below, and a holding portion 14b that wraps around the outer circumference of the seat inner shell 12 at the rear of the pocket portion 14a. A resin tape (not shown) is fixed around the entire circumference of the pocket portion 14a and the entire circumference of the holding portion 14b, and the resin tape has locking holes that engage with the hook-shaped claws 22.

[0027] (3) Retractable Upholstery Structure As shown in Figures 2(A) and 2(C), for example, the seat 2 is recessed upward when viewed from the front and has a deeper rear when viewed from the side, and the seat inner shell 12, cushioning material 13 and upholstery 14 also have a similar shape. In this embodiment, the upper surface of the seat inner shell 12 is the pressure-receiving surface, but it is recessed upward when viewed from the front. Therefore, the upper surface is not flat. Also, the rear end of the seat 2 (and seat inner shell 12) has raised corners on both sides, and therefore the seat 2 has a three-dimensional shape with its rear end recessed upward. The seat inner shell 12, base material layer 15, and surface layer 16 that make up the seat 2 are all three-dimensional in shape. Then, at the recessed part of the seat 2 (roughly the front and rear positions where the seated person's tailbone makes contact), retractable parts 23 that pull the upholstery 14 downward are formed to extend long to the left and right.

[0028] The base layer 14 of the cushioning material 13 is composed of a three-dimensional mesh structure made by bonding (welding) countless elastic and bendable resin fibers, such as polyester fibers. Therefore, it has a structure with high breathability and durability. On the other hand, the surface layer 16 is made of felt material (vertical nonwoven fabric) made of fine resin fibers that have been solidified (bonded together), providing breathability while offering a soft feel to the buttocks and thighs of the person sitting on it.

[0029] As shown in Figure 6(A), the surface layer 16 is formed to extend outside the outer circumference of the base layer 15. The outer circumference of the base layer 15 is designed to be located at the periphery of the seat inner shell 12, and the outer peripheral portion 16a of the surface layer 16 is set to wrap around (be wrapped around) the outside of the seat inner shell 12 beyond the base layer 15. Therefore, the outer peripheral portion 16a is a wrapped portion. Since the surface layer 16 deforms slightly under compression against its elasticity, the upholstery 14 is held taut by attaching it to the seat inner shell 12 while the surface layer 16 is compressed. Note that "wrapped portion" has the same meaning as "wrapping portion". The wrapped portion includes both cases where it is formed over the entire circumference of the surface layer 16 and cases where it is formed over a part of the entire circumference of the surface layer 16. Therefore, the wrapped portion may be present in at least a part of the outer circumference of the surface layer 16. The outer circumferential surface of the base layer 15 is embraced by the wrap-around portion of the surface layer 16, preventing slippage between the surface layer 16 and the base layer 15. Furthermore, the embrace of the surface layer 16 by the upholstery 14 suppresses the base layer 15 from slipping relative to the shell member. Moreover, even if the user's body comes into contact with the edge of the body support unit, the body is supported by the soft surface layer, so the body does not feel strained. Furthermore, because the upholstery wraps around the soft surface layer, the upholstery can be kept taut by the elastic force of the surface layer. Consequently, it also looks good. In addition, if wrap-around portions are provided on the left and right sides of the surface layer 16, the slip-prevention effect of the surface layer 16 is greatly enhanced, and the softness against the user's body is also superior. Furthermore, the front portion of the surface layer 16 can be wrapped downwards, in which case the phenomenon of the user's thighs being pushed upwards can be suppressed.

[0030] Figure 6(A) shows the side portion of the seat 2, but the wrap-around (wrap-around) structure of the surface layer 16 can be applied to the entire circumference of the seat 2.

[0031] As shown in Figures 4 to 6, a single string 24, as an example of a tensioning member, is placed in the area of ​​the surface layer 16 corresponding to the retraction portion 23. The string 24 penetrates the surface layer 16 at both the left and right ends of the area and is pulled out downwards. This allows the cushioning material and upholstery to be held in a predetermined position relative to the shell member, thereby stabilizing and improving the quality of the product. For example, in a seat, the upper surface of the shell member and cushioning material is recessed downwards to ensure a good fit for the user. In this case, the upholstery is pulled downwards by a retraction member to prevent it from lifting, but the retraction member can also be used as a positioning member, thus simplifying the structure. Furthermore, the left and right downward portions 24a of the string 24 penetrate the base material layer 15 and the seat inner shell 12 and are pulled out below the seat inner shell 12. As shown in Figures 3, 5, and 6, the left and right downward portions 24a are bound together at the lower surface of the seat inner shell 12.

[0032] In this case, as shown in Figures 6(A) and 6(B), a groove-shaped retraction section 23 is formed on the upper surface of the surface layer 16 by strongly pulling the downward portion 24a of the cord material 24. The upholstery fabric 14 is then sewn to the upper surface of the surface layer 16 at the location of the retraction section 23 by sewing with a sewing machine. In Figures 2(C) and 6(E), the thread exposed by the sewing machine is indicated by the reference numeral 23a.

[0033] Furthermore, the upholstery 14 can be sewn only to the surface of the outer layer 16, or it can be sewn by piercing the outer layer 16 with a sewing machine needle and holding the upholstery 14 and the outer layer 16 together with sewing thread. Alternatively, a reinforcing strip of fabric can be sewn to the upper surface of the outer layer 16, and the upholstery 14 can be sewn to this strip of fabric. In addition, a cord material 24 can be secured to the upper surface of the outer layer 16 using a method such as overcast stitching, and the upholstery 14 can be sewn to this cord material 24. For example, as shown in Figure 3(B), the seat inner shell 12 has left and right insertion holes 25 for passing the cord material 24 through.

[0034] It is also possible to attach a plug to the pull-in hole 25 to press the downward portion 24a of the cord material 24 against it. For example, a push rivet can be used as the plug. Figures 4 and 6(C) and (D) show the insertion holes 26 of the cord material 24 on the surface layer 16, but this is for convenience only and the insertion holes 26 do not need to be there. That is, the insertion holes 26 are formed by the jig during the assembly process, but when the jig is removed the insertion holes 26 close up and do not remain as insertion holes 26.

[0035] (4) Summary of the first embodiment The seat 2 is manufactured (assembled) in the following steps. First, the upholstery 14, the surface layer 16, the base layer 15, and the seat inner shell 12 are prepared as separate components. Then, the cord material 24 is attached to the surface layer 16. In this case, although one cord material 24 is used in the drawing, if one cord material 24 is used, it is sufficient to simply insert the downward-facing portion 24a into the surface layer 16, and it is not necessarily required to fix the cord material 24 to the surface layer 16.

[0036] On the other hand, it is also possible to use two strings 24, in which case the upper ends of the left and right strings 24 need to be fixed to the upper surface of the surface layer 16. In order to form a groove-shaped recess 23 in the surface layer 16, it is preferable to use one string 24 and use the string 24 to recess the surface layer 16 downwards. The string 24 needs to be inserted through the surface layer 16, but the string 24 can also be inserted by using a needle-shaped jig such as a sewing needle to pierce the surface layer 16 and pull it out.

[0037] Alternatively, the surface layer 16 can be spread open with a funnel-shaped jig, and the string material 24 can be passed through the jig. Insertion into the base layer 15 is done similarly. In any case, it is preferable to fix both the surface layer 16 and the base layer 15 to the jig and use a mask or the like to accurately insert the string material 24 into the predetermined position.

[0038] After attaching the cord material 24 to the surface layer 16, the upholstery 14 is placed on top of the surface layer 16 in a precisely positioned position, and then, as shown in Figure 6(E), the upholstery 14 is fixed to the surface layer 16 by sewing the area of ​​the retraction portion 23. Next, with the downward-facing portion 24a of the cord material 24 inserted through the base layer 15 and the seat inner shell 12, the upholstery 14 is placed over the surface layer 16, the base layer 15 and the seat inner shell 12 and fixed to the seat inner shell 12. Then, the left and right downward-facing portions 24a of the cord material 24 are pulled to form the retraction portion 23, and the left and right downward portions 24a are tied together in that state. This completes the two-layer seat 2 with the retraction portion 23 formed.

[0039] Furthermore, since the majority of the cushioning material 13 is composed of the base layer 15, it can maintain high resilience and durability, while the surface layer 16 is made of a dense and soft material like felt, so it is soft against the buttocks and thighs of the person sitting, providing excellent comfort. In addition, both the cushioning material 13 and the base layer 15 are made up of countless fibers, and the gaps inside are continuous pores, so they have excellent breathability and do not cause stuffiness.

[0040] In particular, by using a material in which fibers are woven in the longitudinal direction (the direction in which the base layer 15 and the surface layer 16 are laminated) for the surface layer 16, the cushioning properties of the surface layer 16 can be improved, making it less likely for the occupant to feel the unevenness of the base layer 15. As a specific example of such a material, V-lap (registered trademark) manufactured by Teijin Limited can be cited.

[0041] Furthermore, in this embodiment, since it has a retractable section 23, even if the seat 2 has a shape with a large recess in the upper surface of the rear and a high three-dimensionality, it is possible to prevent the upholstery 14 from floating and ensure a beautiful appearance. If the front part 2a of the seat 2 is of the roll-up type as in this embodiment, the upholstery 14 is pulled forward with the front part 2a of the seat 2 rolled up. Without the retractable section 23, the upholstery 14 may float significantly when not seated, resulting in an unsightly appearance. However, with the retractable section 23, the upholstery 14 is kept overlapping the surface layer 16 even when the front part 2a of the seat 2 is rolled up, resulting in an aesthetically pleasing finish, which is particularly preferable.

[0042] And in this embodiment, since the string material 24 is attached to the surface layer 16, the surface layer 16 is attached to the base material layer 15 in an accurately positioned state. On the other hand, since the gusset 14 is fixed to the surface layer 16 in advance, the surface layer 16 is also attached to the base material layer 15 in an accurately positioned state. Also, since the gusset 14 is attached to the surface layer 16 in advance, the assembly work can be performed quickly.

[0043] The thicknesses of the base material layer 15 and the surface layer 16 can be arbitrarily set according to the characteristics of the target unit. However, when applied to the seat 2 as in the embodiment, if the base material layer is set to a thickness of several cm (for example, 2 to 5 cm) and the surface layer is set to a thickness of several mm to more than 10 mm, it is possible to ensure the necessary cushioning property and durability as the seat 2 while ensuring a soft touch, which is preferable.

[0044] As described above, when the outer peripheral portion 16a of the surface layer 16 is made to wrap around the outside of the seat inner shell 12, the elastic deformation of the surface layer 16 can be used to hold the gusset 14 in a stretched state, so that a beautiful appearance can be maintained. Also, the gusset 14 can be held in a state where it does not come off even when its periphery is fitted into the hook-shaped claws 22 of the seat inner shell 12.

[0045] In this embodiment, the retraction portion 23 is formed in a groove shape, but the retraction portion 23 does not necessarily have to be formed in a groove shape. Also, it is possible to make the location where the string material 24 is attached to the surface layer 16 different from the sewing location of the gusset 14. Furthermore, it is also possible to attach the gusset 14 to the surface layer 16 at locations on both the front and rear sides sandwiching the attachment portion of the string material 24 to the surface layer 16.

[0046] In the embodiment, the bending deformation allowance portion 12a at the front of the seat inner shell 12 has an uneven shape, but it is possible to thin the portion of the base material layer 15 where the seat inner shell 12 overlaps the uneven portion. Alternatively, it is also possible to form the lower surface of the base material layer 15 into an uneven shape that meshes with the uneven portion of the seat inner shell 12.

[0047] The base material layer 15 is made by cutting out (punching out) an isotropic sheet material (block material) provided by the manufacturer. Making it thinner or forming uneven shapes (three-dimensional shapes) partially can be achieved using a heatable press mold. The material is square, and molding and trimming the margins are performed as a series of steps. The surface layer 16 is made by punching out the isotropic sheet material of the material.

[0048] In this embodiment, the upholstery 14, the surface layer 16, the base material layer 15, and the seat inner shell 12 are held in a state where they do not shift horizontally relative to each other via the string material 24. Therefore, the string material 24 also functions as a displacement prevention means. When a person leans on the backrest 3, the seat 2 tends to be pushed forward by the person's buttocks. However, since the seat 2 is held by the string material 24 so as not to be able to slide forward, the usability is high.

[0049] The string material 24 has the first function of pulling in the upholstery 14, but also plays a role in preventing the mutual horizontal displacement of the upholstery 14, the surface layer 16, the base material layer 15, and the seat inner shell 12. Therefore, the string material 24 also functions as a positioning member. In this embodiment, since two string materials 24 are arranged on the left and right, it is also excellent in resistance to horizontal displacement and torsion in the front, rear, left, and right directions.

[0050] In the embodiment of the present application, the strip cloth 41 for pulling in the upholstery 14 also functions as a positioning member that prevents the relative horizontal displacement of the upholstery 14, the surface layer 16, the base material layer 15, and the seat inner shell 12.

[0051] (5) Base material layer of the second embodiment Figures 7 to 11 show the second embodiment. The basic structure of this embodiment is the same as that of the first embodiment, and the seat inner shell 12 has the same structure as that of the first embodiment. The upholstery 14, the surface layer 16, and the base material layer 15 adopt a different mode from the first embodiment. The materials and basic functions of each element are the same as those of the first embodiment.

[0052] In this embodiment, one feature is the form of the outer periphery of the base material layer 15. That is, as clearly shown in FIGS. 11(A) and 11(B), the outer peripheral surface 15a of the base material layer 15 is curved in a rounded form. Also, a flange 35 is formed in the middle of the thickness direction.

[0053] Figure 9 schematically shows the processing procedure for the base layer 15. Specifically, the material for the base layer 15 is a rectangular, uniformly thick material (sheet material) 36, shown by a dashed line. This material is heated and pressed between a pair of press dies 37 and 38, partially shown in Figure 9(B), to form a three-dimensional shape and remove excess material. In other words, by using the inner edges of the pair of press dies 37 and 38 as cutting blades, the three-dimensional molding and punching are performed as a series of processes. The press dies 37 and 38 are set so that there is a gap between the inner edges of both press dies when they are brought as close together as possible, thereby forming a flange 35. By cutting the excess material while the flange 35 is held down by the pair of press dies, the series of processes of molding and cutting can be performed smoothly. Furthermore, the shape stability is excellent. In addition, because the outer circumference is maintained by the flange 35, the outer circumference does not expand due to springback, resulting in excellent reliability. Because the flange 35 has high rigidity, it is possible to improve the positioning effect by pressing it against the wall of the shell member. Furthermore, when setting the base material layer 15 onto the shell member, the flange 35 can also be used for positioning. For example, a notch to serve as a marker may be formed on the flange 35, a notch that fits into a projection formed on the shell member may be formed on the flange 35, or an engagement hole that fits into a pin protruding from the shell member may be formed on the flange 35.

[0054] The pair of press molds 37 and 38 are heated to a temperature sufficient to soften the resin material of the base layer 15. Therefore, it is easy to create a three-dimensional shape from a flat material 36 and to smooth the surface. Furthermore, because the outer peripheral surface 15a is curved, the pressure from the press molds 37 and 38 acts on it, easily softening the wire group (resin fiber group) and forming a smooth surface. Since the outer peripheral surface 15a is a smooth surface, there are no problems such as the wire (resin fiber) of the material unraveling or pieces falling off. The base layer 15 maintains its shape, preventing material unraveling and stabilizing and improving quality. Because the outer peripheral part of the base layer 15 has a tapered cross-sectional shape, it prevents the outer peripheral part of the unit from becoming angular and forms a smooth outer peripheral part. Therefore, it has a good appearance and ensures a soft feel against the body. In addition, it has the advantage of being able to easily process using commercially available materials of equal thickness in sheet or block form, thus reducing costs.

[0055] The outer circumferential surface 15a of the base layer 15 can have a shape different from that shown in the figure. For example, a wedge shape composed of upper and lower flat inclined surfaces can be adopted. It is also possible to have one of the upper and lower surfaces be curved and the other flat. It is also possible to form markers or positioning parts (projections or grooves) on one or both of the curved or inclined upper and lower surfaces to accurately position the base layer 15 on the seat inner shell 12.

[0056] The thickness of the flange 35 can be set to approximately 0.5 to 2.0 mm, and its width (projection dimension) to approximately 1 to 3 mm. In the illustrated example, the flange 35 is formed along its entire length, but it is not necessary for the flange 35 to be formed along its entire length. It is possible for there to be one or more locations where the flange 35 is absent. The notched areas where the flange 35 is absent can be used for positioning relative to the seat inner shell 12. That is, by fitting the notched areas formed in the flange 35 with projections provided on the seat inner shell 12, the base material layer 15 (cushion material 13) can be accurately positioned on the seat inner shell 12.

[0057] The width of the flange 35 does not necessarily have to be constant around its entire circumference. It is possible to make it partially protrude and have the protruding portion function as a positioning portion for the seat inner shell 12. It is possible to make a hole in the protruding portion and have it fitted onto a positioning pin provided in the seat inner shell 12. As can be seen from Figures 11(A) and (B), because the flange 35 is hard, it tends to bite into the surface layer 16. Therefore, the flange 35 also functions as a means of preventing slippage between the surface layer 16 and the base material layer 15.

[0058] As can be seen from the comparison between Figure 11(B) and Figure 6(A), when the outer peripheral surface 15a of the base layer 15 is curved or inclined, the upper surface on the left and right sides of the seat 2 becomes a smooth surface. This improves the appearance and also makes it softer against the human body.

[0059] (6) As clearly shown in the surface view figures 11(A) and (B) of the second embodiment, the outer peripheral portion 16a of the surface layer 16 is wrapped around the seat inner shell 12 at least at the left and right sides and the front end of the seat 2. Since the rear end of the seat inner shell 12 is an upward-facing wall, it is not necessary to wrap the outer peripheral portion 16a of the surface layer 16 around the rear end of the seat inner shell 12. However, it is possible to wrap the surface layer 16 towards the lower surface of the seat inner shell 12 even at the rear end of the seat inner shell 12.

[0060] Now, if the surface layer 16 is wrapped around the seat inner shell 12 at three edges—the left and right sides and the front end—and the surface layer 16 is simply a flat plate, wrinkles will form at the front corner where the side and front end meet. These wrinkles (unevenness) are visible to a person through the upholstery 14, which creates an unsightly problem. Furthermore, assembling the surface layer 16 is also troublesome.

[0061] Therefore, in this embodiment, the surface layer 16 is pre-formed into a tray shape and fitted into the base layer 15. That is, as shown in Figure 11(C), when punching out the surface layer 16 from a rectangular material, a notch 39 is pre-formed at the corner where the side portion 16b and the front portion 16c are connected, and the surface layer 16 is formed into a tray shape by raising the side portion 16b and the front portion 16c and sewing their ends together.

[0062] As described above, when the surface layer 16 is formed in a tray shape, the two are precisely positioned simply by placing it on top of the base layer 15. In the tray shape, the corners are angular, but when the upholstery 14 is covered, the front corners of the surface layer 16 deform to match the front corners of the seat inner shell 12, maintaining a wrinkle-free (uneven) state. Furthermore, the holding effect of the base layer 15 is enhanced, resulting in excellent slip prevention. In addition, since the surface layer 16 can be attached to the base layer 15 easily and accurately, the assembly of the body support unit is also simplified.

[0063] As shown by the dashed line in Figure 11(C), by forming a notch 39 at the rear of the surface layer 16, it is possible to form the surface layer 16 into a tray shape with walls around its entire circumference. In this case, since the surface layer 16 completely covers the base material layer 15 around its entire circumference, relative slippage between the surface layer 16 and the base material layer 15 can be reliably prevented.

[0064] (7) Upholstery and retraction structure of the second embodiment In the first embodiment, with reference to Figure 3, it was explained that the upholstery 14 is connected to the hook-shaped claws 22 of the seat inner shell 12. The same applies to this embodiment, and as shown in Figure 10, a number of edge hook-shaped claws 22a arranged in the circumferential direction are formed on the back surface of the seat inner shell 12. The holding portion 14b of the upholstery 14 is connected to the edge hook-shaped claws 22a. The connection to the edge hook-shaped claws 22a is temporary, and the holding portion 14b is fixed to the seat inner shell 12 with a stapler.

[0065] As shown in Figures 11(A) and 10, the upholstery 14 also has a pocket portion 14a that covers the bending deformation allowable portion 12a of the seat inner shell 12 from below. The pocket portion 14a is constructed as a separate component from the main body of the upholstery 14 and is attached to the main body. In Figure 10, the outline of the pocket portion 14a is shown with a thick line, and the elements covered by the pocket portion 14a are shown with a solid line. The holding portion 14b of the upholstery 14 is partially shown with parallel diagonal lines. In Figure 10, the bending deformation allowable portion 12a of the seat inner shell 12 is abstracted away and shown as a blank space.

[0066] The pocket portion 14a is temporarily secured to an internal hook-shaped claw 22b located immediately behind the bending deformation allowable portion 12a of the seat inner shell 12. The rear edge of the pocket portion 14a is fixed to the seat inner shell 12 with staples. Two internal hook-shaped claws 22b are arranged symmetrically on each side of the vertical center of the seat inner shell 12.

[0067] Similar to the first embodiment, the upholstery 14 is pre-sewn to the surface layer 16 at the pull-in portion 23. In Figure 8, the sewn portion is indicated by reference numeral 40. Note that reference numeral 40 is the same as reference numeral 23a shown in Figure 2(C). In this embodiment, two strips of fabric 41 are used as tensioning material. The base end (upper end) of the strips of fabric 41 is sewn to the lower surface of the surface layer 16. Note that the strips of fabric 41 can also be attached to the upholstery 14 and passed through the surface layer 16. Alternatively, the strips of fabric 41 can be sewn to the upper surface of the surface layer 16 and passed through the surface layer 16 to be pulled downwards. In any case, it is preferable to sew the strips of fabric 41 to the upholstery 14 as well.

[0068] In the rear portion of the seat inner shell 12, where the weight of a person is strongest, numerous groups of vertical slits 42 and inclined slits 43 are formed to allow for sinking and deformation under the weight of the person. The left and right strips of fabric 41 are pulled downward from the two vertical slits 42 located at the rear, and their ends are secured to internal hook-shaped claws 22b located near the center of the left and right sides. Consequently, notches are formed at the ends of the strips of fabric 41.

[0069] As clearly shown in Figure 10, the pocket portion 14a of the upholstery 14 is connected to the internal hook-shaped claw 22b, and as can be understood from the dotted line indicating the tip of the strap 41 in Figure 10, the tip of the strap 41 is covered from below by the pocket portion 14a. Furthermore, since the leading edge of the pocket portion 14a is fixed to the seat inner shell 12 with a stapler, the strap 41 is held in a state where it cannot come off the internal hook-shaped claw 22b. The strap 41 can also be locked to the internal hook-shaped claws 22b located on the outside in the left-right direction.

[0070] In this embodiment, the strap fabric 41 is connected to an internal hook-shaped claw 22b that temporarily fastens the pocket portion 14a of the upholstery 14, eliminating the need for a dedicated fastening means to secure the strap fabric 41 and thus simplifying the structure. Furthermore, since the pocket portion 14a of the upholstery 14 functions as a means to prevent the strap fabric 41 from coming off, there is no need to fasten the strap fabric 41. Therefore, the assembly of the seat 2 can be carried out efficiently. It is also possible to use a string material with a loop formed at the end instead of the strap fabric 41. It is also possible to use resin tape as the strap fabric 41.

[0071] (8) Positioning members of the second embodiment As shown in Figure 8, cloth side positioning members 44 are sewn to the lower left and right side portions of the surface layer 16, and rear positioning members 45 are sewn to the lower left and right rear portions of the surface layer 16. The side positioning members 44 and rear positioning members 45 are examples of positioning means that hold the surface layer 16 in a position that prevents displacement relative to the seat inner shell 12. However, since the base material layer 15 is held in place by the surface layer 16, the side positioning members 44 and rear positioning members 45 also have the function of positioning the base material layer 15 relative to the seat inner shell 12.

[0072] The strap fabric 41 and the rear positioning member 45 are sewn to the surface layer 16 and the upholstery 14. In other words, the strap fabric 41 and the rear positioning member 45 are sewn together with the surface layer 16 and the upholstery 14 as a single unit. At the location of the sewn portion 40 shown in Figure 9(A), the strap fabric 41 and the rear positioning member 45 are sewn together with the upholstery 14 as a single unit. Therefore, the rear positioning member 45 also exerts a pulling effect on the upholstery 14.

[0073] The side positioning member 44 and the rear positioning member 45 are fitted into the edge hook-shaped claws 22a formed on the seat inner shell 12. Therefore, the side positioning member 44 and the rear positioning member 45 have multiple notches 46 (see Figure 8) formed in them.

[0074] As clearly shown in Figure 11(B), the side positioning members 44 and the rear positioning member 45 and the holding portion 14b of the upholstery 14 are fitted into a common edge hook-shaped claw 22a. To put it another way, the edge hook-shaped claw 22a is used as a fixing means for the side positioning member 44 and the rear positioning member 45 to temporarily fix the upholstery 14. The rear positioning member 45 can also be made of a resin sheet.

[0075] The side positioning members 44 and rear positioning members 45 are held in place from below by the holding portion 14b of the upholstery 14. Thus, the side positioning members 45 and rear positioning members 45 are held in place without coming loose simply by connecting to the edge hook-shaped claws 22a. Consequently, no special elements are required to fix the side positioning members 44 and rear positioning members 45, which simplifies the structure and improves the workability of assembling the seat 2.

[0076] In this embodiment, when the front portion 2a of the seat 2 is rolled downward to adjust the depth of the seat 2, the cushioning material 13 tends to be pulled forward. However, since the forward sliding of the surface layer 16 is prevented by the rear positioning member 45, the seat 2 is rolled in while preventing the cushioning material 13 from sliding. Therefore, it does not cause discomfort to the user and high quality can be maintained.

[0077] The circumferential lengths of the side positioning members 44 and rear positioning members 45 can be set arbitrarily. The side positioning members 44 and rear positioning members 45 can be sewn to the upper surface of the surface layer 16, but as in this embodiment, sewing them to the lower surface of the surface layer 16 is preferable in terms of maintaining aesthetics because the side positioning members 44 and rear positioning members 45 do not show through the upholstery 14, nor do their outer shapes appear on the upholstery 14. The side positioning members 44 and rear positioning members 45 can also be separated into multiple pieces each. The positioning members may be strings or thin sheet materials. In that case, the positioning members can be connected over a wide area of ​​the surface layer, resulting in a high slip prevention effect and excellent strength.

[0078] Furthermore, in this embodiment, the rear positioning member 45 is set to the same left-right width as the retractable portion 23, and its front end is sewn to the location of the retractable portion 23. Therefore, the position of the retractable portion 23 can also be accurately maintained. In this case, it is possible to sew the rear positioning member 45, the surface layer 16, and the upholstery 14 together as a single unit, or it is possible to sew the rear positioning member 45 only to the surface layer 16. Furthermore, it is also possible to construct the side positioning member 44 and the rear positioning member 45 from a single piece of fabric.

[0079] (9) Although embodiments of the present invention have been described in more detail than the other variations, the present invention can be further concretized in various ways. For example, the application is not limited to the seats of swivel chairs, but can also be applied to single-seater or multi-seater sofas, as well as the seats and backrests of fixed chairs such as theater seats.

[0080] The surface material is not limited to nonwoven fabric or felt; for example, thick knitted fabrics such as rib knit can also be used. The base layer may consist of multiple layers. The surface layer does not need to be placed over the entire surface of the base layer; it may be placed only in the areas where the seated person's body pressure acts.

[0081] It is also possible to temporarily fix the surface layer to the base layer by adhesive or other means. In this case, it is possible to temporarily fix the surface layer to the base layer and then attach the upholstery to the surface layer, or to attach the upholstery to the surface layer first and then temporarily fix the surface layer to the base layer. The base layer does not necessarily have to be a three-dimensional mesh. In addition, the surface layer can be made of nonwoven fabric made from synthetic resin fibers, or compressed cotton material made by intertwining and compressing resin fibers or natural fibers.

[0082] The present invention can also be suitably applied to backrests. Backrests often have a forward-facing protrusion where the user's lower back and hip bones make contact in order to ensure lumbar support. Therefore, the cushioning material has a three-dimensional shape, and since the present invention can easily realize a three-dimensional shape, it is also suitable for use as a backrest. When applied to a backrest, it is also possible to place the lumbar pad between the surface layer and the base material layer.

[0083] (10) Matters disclosed in this application This application discloses the following aspects:

[0084] A chair body support unit according to the first embodiment comprises a shell member made of synthetic resin with one side being a pressure-receiving surface, a cushioning material overlapping the pressure-receiving surface of the shell member, and upholstery covering the cushioning material. The cushioning material includes a base layer made of a three-dimensional mesh formed by intertwining a group of curved elastic fibers made of synthetic resin, and a surface layer made of a nonwoven fabric, felt, or knitted fabric having a group of fibers extending in the thickness direction. The surface layer directly overlaps the base layer.

[0085] According to the first embodiment, the surface layer is directly superimposed on the base material layer, resulting in a simple structure and high versatility. In the second embodiment, the chair body support unit has, in the first embodiment, a wrap-around portion on the outer periphery of the surface layer that covers the end face of the base material layer.

[0086] In the second embodiment, the configuration is such that "the base material layer is a single item." According to the second embodiment, because it is easy to handle, assembly work can be performed quickly and accurately.

[0087] As an example of the development of the first or second embodiment, the third embodiment has a wrapped portion on the outer periphery of the surface layer that covers the end face of the base material layer. According to the third embodiment, the contact with the edge of the chair is soft when the seated person's body touches it. In addition, the edges of the unit can be rounded, resulting in a superior aesthetic appearance.

[0088] As an example of any one of the first to third embodiments, in the fourth embodiment, the pressure-receiving surface of the shell member is formed as a non-flat three-dimensional surface. The base material layer is formed as a three-dimensional shape that overlaps the pressure-receiving surface. According to the fourth embodiment, both the shell member and the base material layer are three-dimensional surfaces and their surface layers are soft and conform to the base material layer, thus providing excellent fit.

[0089] The chair body support unit according to the fifth embodiment, in any one of the first to fourth embodiments, has a roll-up deformation allowance portion in the base layer that can be bent together with the surface layer. The roll-up deformation allowance portion and the surface layer are maintained in an overlapping state. According to the fifth embodiment, it can be applied to adjusting the depth of the chair seat and the height of the backrest. In addition, the unity of the cushioning material can be maintained when the chair seat is rolled up.

[0090] In the sixth embodiment, in any one of the first to fifth embodiments, the base material layer is sized to overlap the entire pressure-receiving surface of the shell member, and the sheet-like surface layer is superimposed on the base material layer so as to cover its entire surface. In the sixth embodiment, a soft contact with the user's body can be ensured.

[0091] The chair body support unit according to the seventh embodiment has a multi-layer structure for the base material layer in any one of the first to sixth embodiments. In this embodiment, the base material layer is easy to handle, and the body support unit can be assembled quickly and accurately.

[0092] The sheet-like surface layer is superimposed on the base material layer so as to cover its entire surface. According to the eighth embodiment, it is possible to prevent the cushioning material from shifting on the shell member. According to the seventh embodiment, the function of the base material layer can be improved by changing the elasticity, strength, and density of each layer of the base material layer.

[0093] The chair body support unit according to the eighth embodiment further includes a positioning member that prevents the upholstery, surface layer, base material layer, and shell member from sliding relative to each other, in any one of the first to seventh embodiments. According to the eighth embodiment, displacement of the shell member and cushioning material can be prevented.

[0094] In the ninth embodiment, the chair body support unit, in the eighth embodiment, has the positioning member penetrating at least the base material layer and the shell member. According to the ninth embodiment, displacement between the base material layer and the shell member can be suppressed.

[0095] The chair body support unit according to the tenth embodiment includes, in any one of the first to ninth embodiments, at least one of the following: a configuration in which the outer periphery of the base material layer is tapered outward, and a configuration in which the outer periphery surface is flat and smooth. According to the tenth embodiment, the base material layer can be stably placed on the shell member.

[0096] In the eleventh embodiment, the chair body support unit has a flange formed on at least a portion of the outer circumference of the base material layer in any one of the first to tenth embodiments. According to the eleventh embodiment, the shape retention of the base material layer can be improved, and the flange can be used for positioning, etc.

[0097] In the twelfth embodiment, the chair body support unit is provided with a positioning member on the surface layer, which is wrapped around the back side of the shell member and connected to the shell member, in any one of the first to eleventh embodiments. According to the twelfth embodiment, the surface layer and the base material layer can be positioned while preventing misalignment. In the twelfth embodiment, the chair body support unit is provided with the positioning member on two sides located on opposite sides of the center of the surface layer, in any one of the first to eleventh embodiments.

[0098] In the 13th embodiment, as an extension of the 12th embodiment, the positioning member is provided on two sides located on opposite sides of the center of the surface layer. In the 13th embodiment, the stability of the surface layer can be improved.

[0099] In the 14th embodiment, the chair body support unit, in any one of the first to 13 embodiments, has a positioning member that is made of cloth or other flexible sheet material. According to the 13th embodiment, the surface layer can be stably positioned. Furthermore, the mounting strength between the surface layer and the positioning member is excellent.

[0100] In the 15th embodiment, the chair body support unit, in any one of the first to 14 embodiments, has a surface layer formed in the shape of a tray with walls, and the walls cover the outer periphery of the base material layer. According to the 15th embodiment, displacement of the base material layer can be particularly suppressed. Furthermore, assembly of the chair body support unit becomes easier. In addition, the upholstery can be made to adhere closely to the surface layer, improving the appearance of the chair body support unit.

[0101] In the 16th embodiment, the chair body support unit is configured such that, in any one of the first to 15 embodiments, the front portion of the shell member and the base material layer is formed into a retractable deformation-allowable portion. The surface layer is formed by a front wall and side walls that cover the deformation-allowable portion. According to the 16th embodiment, the laminated state of the surface layer and the base material layer can be firmly maintained when wrapped.

[0102] The 17th aspect is a method for manufacturing a body support unit for a chair. This method is a method for manufacturing a body support unit for a chair, comprising the steps of: preparing a shell member made of synthetic resin having one side as a pressure-receiving surface that is not flat; preparing a cushioning material to overlap the pressure-receiving surface; preparing upholstery to cover the cushioning material; and attaching the upholstery after the cushioning material has been placed on the shell member, wherein the step of preparing the cushioning material comprises the steps of: preparing a base layer made of a three-dimensional mesh formed by intertwining a group of curved elastic fibers made of synthetic resin; and preparing a surface layer made of a nonwoven fabric-like material, felt material, or knitted fabric having a group of fibers extending in the thickness direction, wherein the step of preparing the base layer comprises the steps of: preparing a sheet-like material of equal thickness; and processing the material into a three-dimensional shape by heating and pressing it.

[0103] This manufacturing method allows for the easy production of three-dimensional base layers using plate-like or block-like materials of uniform thickness.

[0104] The present invention can be embodied in a body support unit for a chair, such as a seat or backrest. Therefore, it can be used industrially.

[0105] 2 Seat 2a Front (part that allows for winding deformation) 3 Backrest 12 Seat inner shell as an example of a shell member 12a Part that allows for bending deformation 13 Cushioning material 14 Upholstery 14a Pocket part 14b Holding part (winding part, wrap-around part) 15 Base material layer 15a Outer surface 16 Surface layer 16a Outer surface (winding part) 22, 22a, 22b Hook-shaped claws 23 Retractable part 24 Retractable cord material that also serves as a positioning member 35 Flange 37, 38 Press mold 39 Notch for making the surface layer three-dimensional 41 Retractable strip fabric that also serves as a positioning member 44 Side positioning member 45 Rear positioning member

Claims

1. A body support unit for a chair comprising: a shell member made of synthetic resin with one side being a pressure-receiving surface; a cushioning material overlapping the pressure-receiving surface of the shell member; and upholstery covering the cushioning material, wherein the cushioning material includes a base layer made of a three-dimensional mesh formed by bonding together a group of curved synthetic resin elastic fibers, and a surface layer made of a nonwoven fabric, felt, or knitted fabric having a group of fibers extending in the thickness direction, and the surface layer directly overlapping the base layer.

2. The body support unit for a chair according to claim 1, wherein the base material layer is a single product.

3. The outer periphery of the surface layer has a wrapped portion that covers the end face of the base material layer, the chair body support unit according to claim 1.

4. The body support unit for a chair according to claim 1, wherein the pressure-receiving surface of the shell member is formed as a non-flat three-dimensional surface, and the base material layer is formed in a three-dimensional shape that overlaps the pressure-receiving surface.

5. The body support unit for a chair according to any one of claims 1 to 4, wherein the base material layer has a portion that allows for winding deformation, which can be bent together with the surface layer, and the state in which the winding deformation portion and the surface layer overlap is maintained.

6. The body support unit for a chair according to any one of claims 1 to 4, wherein the base material layer is sized to overlap the entire pressure-receiving surface of the shell member, and the sheet-like surface layer is superimposed on the base material layer so as to cover its entire surface.

7. The body support unit for a chair according to any one of claims 1 to 4, wherein the base material layer has a multilayer structure.

8. A chair body support unit according to any one of claims 1 to 4, further comprising a positioning member that prevents the upholstery, surface layer, base material layer, and shell member from sliding relative to each other.

9. The chair body support unit according to claim 8, wherein the positioning member penetrates at least the base material layer and the shell member.

10. A method for manufacturing a body support unit for a chair, comprising the steps of: preparing a shell member made of synthetic resin having one side as a pressure-receiving surface that is not flat; preparing a cushioning material to overlap the pressure-receiving surface; preparing upholstery to cover the cushioning material; and attaching the upholstery after the cushioning material has been placed on the shell member, wherein the step of preparing the cushioning material comprises the steps of: preparing a base layer made of a three-dimensional mesh formed by intertwining a group of curved elastic fibers made of synthetic resin; and preparing a surface layer made of a nonwoven fabric-like material, felt material, or knitted fabric having a group of fibers extending in the thickness direction; and the step of preparing the base layer comprises the steps of: preparing a sheet-like material of equal thickness; and processing the material into a three-dimensional shape by heating and pressing it.

Images