Chair body support unit and method for manufacturing the same

Abstract

This technology uses a three-dimensional mesh made of resin fibers as cushioning material, resulting in a soft feel against the body and easy upholstery retraction. [Solution] The cushioning material 13 has a two-layer structure consisting of a base layer 15 made of a highly elastic three-dimensional mesh and a buffer layer 16 made of fine fibers such as felt. A string 24 is attached to the buffer layer 16, and the upholstery 14 is sewn to the buffer layer 16 at the locations where the string 24 is placed. The string 24 has left and right downward-facing portions 24a that are inserted through the buffer layer 16, the base layer 15, and the inner shell 12, and the downward-facing portions 24a are tied together on the back side of the inner shell 12. Because the buffer layer 16 deforms under compression, the upholstery 14 can be strongly pulled in. Since the string 24 is attached to the buffer layer 16 in advance and the upholstery 14 is attached to the buffer layer 16 in advance, the upholstery 14, the buffer layer 16, and the base layer 15 are attached to the inner shell 12 in a positioned manner relative to each other.

Description

Technical Field

[0006] , , , , , ,

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

Background Art

[0002] When the seat or back of a chair has a structure in which a cushion is attached to a resin shell member, the cushion is covered with a covering material (skin material). And, in order to prevent the slack of the covering material, to maintain the overlapping state of the covering material, the cushion and the back plate, or for design reasons, the covering material is partially drawn in toward the shell member.

[0003] And, it has been proposed to use a fastener as a means for drawing in the covering material. As an example thereof, Patent Document 1 discloses that a plate-shaped fastener is sewn to the back of the covering material, and a claw portion provided on the fastener is fitted into a middle plate disposed on the back side of the cushion.

[0004] Now, urethane foam is frequently used as a cushion material for a seat or a backrest of a chair, but urethane foam has problems such as poor air permeability, not necessarily high elastic force, and a tendency to occur a sag where the elastic resilience decreases during use.

[0005] On the other hand, there exists a non-woven fabric-like three-dimensional network body formed by entangling and bonding highly elastic resin fibers that are bent and twisted, and this three-dimensional network body is excellent in air permeability, has a high repulsive force, and is also excellent in durability. Therefore, this three-dimensional network body has been used as a cushion material for a seat or a backrest (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] Three-dimensional mesh materials made from highly elastic resin fibers are widely used in mattresses and other applications. Because they possess excellent durability, cushioning, and breathability, the applicant has long considered using them as cushioning material for chairs, and as part of this effort, disclosed Patent Document 2. However, three-dimensional mesh materials have a rough surface, which presents a problem as it does not feel good against the human body.

[0008] Furthermore, when pulling the upholstery downwards, in a configuration where the upholstery is directly layered on a three-dimensional mesh structure, pulling the upholstery downwards does not compress or deform the mesh structure, preventing the surface from becoming concave. This presents a problem in that the upholstery cannot be pulled in sufficiently.

[0009] The former problem can be solved by using a three-dimensional mesh as the base layer and layering it with a soft cushioning layer that is gentle on the human body. However, in that case, the problem arises of how to form the recessed portion on the surface of a seat or other surface.

[0010] The present invention was made against this backdrop, and aims to disclose a suitable technique for the retraction section when the cushioning material is configured in a multi-layered manner. Furthermore, although this application discloses many novel inventions, these inventions could also be presented as claimed inventions. In other words, disclosing these inventions could also be presented as a problem to be addressed. [Means for solving the problem]

[0011] The present invention includes various configurations, examples of which are specified in each claim. Of these, the invention of claim 1 relates to a body support unit for a chair. "It has a shell member through which the weight of the seated person acts via a cushioning material, and upholstery (surface material) that covers the cushioning material, The upholstery is provided with a retractable section that is pulled toward the shell member. In this basic configuration, "The cushioning material has a laminated structure consisting of a highly elastic base material layer placed on the side of the shell member and a low-elasticity buffering layer placed between the base material layer and the upholstery." The upholstery is connected to the buffer layer at the location of the retraction section, and the buffer layer is pulled toward the shell member via a tensioning member at the location of the retraction section." It has the following characteristics.

[0012] The invention of claim 2 is a preferred extension of claim 1, "The base layer and buffer layer are breathable." It has the following characteristics.

[0013] The invention of claim 3 is a preferred extension of claim 2, "The base material layer is a three-dimensional mesh formed by bonding together a group of curved, elastic synthetic resin fibers, and the buffer layer is a nonwoven fabric, felt, or knitted fabric formed by solidifying a group of fine fibers in an intertwined state." It has the following characteristics.

[0014] The invention of claim 4 is an extension of any of claims 1 to 3, "The upholstery is sewn to the buffer layer, The tensioning member is a string-like material, and one end of the string-like material is positioned on the surface portion of the buffer layer that overlaps with the upholstery or on the back portion that overlaps with the base material layer, and is sewn integrally with the buffer layer and the upholstery. The other end of the string-like material is pulled out to the back side of the shell member. It has the following characteristics.

[0015] In claim 4, when one end of the string-like material is located on the surface portion of the buffer layer, the string-like material penetrates the buffer layer and is drawn out to the side of the base material layer. In this case, the three members may be sewn together with one end of the string-like material sandwiched between the gusset and the string-like material. On the other hand, when one end of the string-like material overlaps the back surface of the buffer layer, the string-like material may be inserted through the base material layer and the shell member. The string-like material is meant to be long and flexible. Therefore, in addition to round strings, it includes strip cloth, leather strings, and straps.

[0016] The invention of claim 5 is an expansion example of claim 2 or 3, "the shell member is a seat inner shell, the drawing-in portion is formed in a single-character shape in the left-right longitudinal direction at a position closer to the rear side, and the front portion of the shell member and the cushion material can be wound downward" and has the following features.

[0017] The invention of claim 6 is an expansion example of claim 1 or 2, "the shell member is a seat inner shell or a back inner shell, and the buffer layer is thinner than the base material layer" and has the following features.

[0018] The invention of claim 7 is directed to a method for manufacturing a body support unit. That is, "a body support unit for a chair in which a cushion material composed of a base material layer and a buffer layer is held via a gusset on one side of a shell member, and a drawing-in portion that enters the side of the cushion material is provided on the gusset" and is directed to a manufacturing method thereof.

[0019] And this manufacturing method includes "a step of preparing the shell member, the base material layer, the buffer layer, the gusset, and the string-like material for drawing-in; a step of integrally sewing the string-like material, the buffer layer, and the gusset together with the string-like material being largely exposed on the back side of the buffer layer; a step of inserting the string-like material through the base material layer and the shell member; The process includes the step of securing the string-like material to the shell member while it is being pulled taut." It has the following characteristics.

[0020] Prior to attaching the string-like material to the buffer layer, inserting the string-like material into the buffer layer and inserting the string-like material into the base layer can be done using a needle-like inserting tool, or by using a jig that penetrates the buffer layer or the base layer.

[0021] The invention of claim 8 is an extension of any of claims 1 to 3, "The tensioning member is a string-like material inserted through a through hole made in the shell member, and the tip of the string-like material is hooked onto a hook-shaped claw provided on the shell member." This is the structure.

[0022] The invention of claim 9 is an extension of claim 8, "The shell member has numerous slits that allow it to stretch and deform under the user's load, and one of these numerous slits is used as a through-hole for inserting the string-like material." This is the structure.

[0023] The invention of claim 10 is also an extension of claim 8, "Numerous hook-shaped claws are formed on the back surface of the shell member for temporarily fastening the upholstery, and these hook-shaped claws are used to temporarily fasten the upholstery as hook-shaped claws for securing the string-like material." This is the structure.

[0024] The invention of claim 11 is an extension of claim 10, "At the location of the hook-shaped claw to which one string-like material is secured, the end of the string-like material is covered with the upholstery, and the upholstery is fixed to the shell member with a stapler." This is the structure. [Effects of the Invention]

[0025] In each of the present inventions, the surface portion of the cushioning material is composed of a soft buffer layer. Therefore, even if the base layer has a highly elastic structure such as a three-dimensional mesh, it feels soft against the user's body, and thus, a high level of comfort can be obtained while maintaining the properties of the base layer. Furthermore, if the base layer has a highly elastic structure such as a three-dimensional mesh, it is difficult to form indentations, which raises concerns that the upholstery may not be fully retracted. However, in the present invention, the buffer layer can be precisely indented, thus ensuring that the upholstery is fully retracted.

[0026] Furthermore, when upholstery is pulled with a string-like material, excessive tension can be applied to specific narrow areas of the upholstery, causing it to twist. However, in the present invention, the buffer layer is pulled to form grooves that act as retraction areas, so excessive tension is not applied to any part of the upholstery, thus preventing twisting. In addition, since the upholstery is connected to the buffer layer, the upholstery can fit into the recesses created in the buffer layer, preventing it from lifting. In other words, the upholstery can be firmly pulled towards the buffer layer.

[0027] Furthermore, if string-like material is attached to the upholstery and inserted into the cushioning layer, base material layer, and shell member, aligning the orientation of each member becomes troublesome, making the assembly of the body support unit difficult. In addition, misalignment may occur between the upholstery and the cushioning layer, and between the cushioning layer and the base material layer, potentially leading to a decrease in quality. However, in the present invention, since the upholstery and the cushioning layer are integrated, the assembly of the body support unit can be performed efficiently, and misalignment of the members can be prevented, resulting in a beautiful finish.

[0028] As described in claim 2, providing breathability to both the buffer layer and the base layer prevents stuffiness and improves comfort for the user. Because the base layer and the buffer layer have high heat dissipation properties, stuffiness can be prevented or suppressed even if the upholstery is not breathable, such as leather.

[0029] As described in claim 3, using a three-dimensional mesh made of synthetic resin as the base layer is preferable because it ensures high elasticity and durability. Furthermore, using nonwoven fabric, felt, or knitted fabric as the buffer layer allows for the use of inexpensive commercially available products, thus providing the benefits of stable quality and cost reduction.

[0030] As described in claim 4, sewing the upholstery to the cushioning layer allows the upholstery and cushioning layer to be easily and accurately integrated by sewing, which is advantageous in terms of cost and quality preservation.

[0031] While resin or metal hooks can be used as tensioning materials, using a string-like material as described in claim 4 allows for firm tensioning of the string-like material, thus ensuring a secure formation of the retraction section. Furthermore, since the string-like material can be tied, it can be easily applied to existing shell members, making it highly practical.

[0032] Regarding the seat of a chair, the depth is adjusted to accommodate differences in the user's physique and preferences. Adjusting the depth by rolling in the front of the seat has advantages such as allowing adjustment without lifting the hips. However, rolling in and unrolling can easily induce slippage between the upholstery and the cushioning layer, and between the cushioning layer and the base layer. However, by using a string-like material as a tensioning material as in claim 4, the upholstery is fixed to the retracted part, and the string-like material penetrates between the cushioning layer and the base layer. This prevents the upholstery from shifting relative to the cushioning layer and the cushioning layer from shifting relative to the base layer, thus maintaining high quality.

[0033] The thickness of the base layer and the buffer layer can be arbitrarily set according to the characteristics of the unit in question, but as in claim 6, it is preferable to make the buffer layer thinner than the base layer (or thicker than the buffer layer) in order to take advantage of the high elasticity function of the base layer. Specifically, setting the thickness of the base layer to a few centimeters (for example, 2 to 4 centimeters) and the buffer layer to a thickness of a few millimeters to more than 10 millimeters is preferable because it ensures a soft touch while maintaining the necessary cushioning and durability when applied to a seat.

[0034] Claim 8 offers the advantage of enabling quick connection work because the string-like material can be hooked onto the hook-shaped claw. Claim 9 utilizes the slit already present in the shell member as an insertion hole, eliminating the need for additional processing of the shell member. Therefore, cost increases can be prevented.

[0035] In claim 10, the hook-shaped claws for attaching the upholstery are also used for connecting the cord-like material, so no additional processing is required on the shell member, thereby reducing costs. In this case, adopting the invention of claim 11 has the advantage that the other end of the cord-like material is held in place by the upholstery and remains engaged with the hook-shaped claw, thus ensuring the connected state of the cord-like material without any extra effort. [Brief explanation of the drawing]

[0036] [Figure 1] 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. [Figure 2] (A) is a separated perspective view of the chair from the front, (B) is a separated perspective view of the chair from the back, and (B) is a perspective view of the seat from the rear and above. [Figure 3] (A) is a downward perspective view of the seat, and (B) is a bottom view of the seat. [Figure 4] This is a top-down, separated perspective view of the seat. [Figure 5] This is a downward-view, separated perspective of the seat. [Figure 6] (A) is a longitudinal front view of the retraction section, a VIA-VIA cross-sectional view of Figure 1(A), (B) is a BB 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). [Figure 7] This figure shows the second to seventh embodiments, and (F) is a cross-sectional view of (E) from the front-end (FF) perspective. [Figure 8] This is a top-view separation perspective of the eighth embodiment. [Figure 9] This is a downward-view, separated perspective view of the eighth embodiment. [Figure 10]The diagram shows the processing of the base material layer, with (A) being a plan view and (B) being a side view. [Figure 11] This is a view of the base of the seat. [Figure 12] (A) is a cross-sectional view of AA in Figure 10, (B) is a cross-sectional view of BB in Figure 10, (C) is a developed view of the buffer layer, and (D) is a bottom view after it has been made into a three-dimensional structure. [Modes for carrying out the invention]

[0037] 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.

[0038] (1) Basic structure of chairs and seats As can be seen from Figure 1, the chair to which this embodiment is applied is a swivel chair commonly used in offices, and the chair comprises a leg assembly 1, a seat 2, and a backrest 3 as its basic elements. The backrest 3 is made of an elastomer-based 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 having five leg wings, and casters are provided at the tip of each leg wing.

[0039] 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.

[0040] The second tilting frame 7 has a back support 9 located in the middle of the left and right sides and extending vertically, and lower side sections 10 located at the bottom and extending horizontally. The lower side sections 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 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 sections 10.

[0041] As shown in Figure 5, the seat 2 of the first embodiment comprises a synthetic resin seat inner shell (shell member: seat plate) 12, a cushioning material 13 placed on top of it, and upholstery (surface material) 14 covering the cushioning material 13. The cushioning material 13 has a two-layer structure consisting of a base layer 15 and a buffer layer 16 placed on top of it. The total thickness of the cushioning material 13 is approximately 35-40 mm, of which the thickness of the base layer 15 is approximately 30-35 mm and the thickness of the buffer layer 16 is approximately 5-10 mm. Woven or knitted fabrics can be used for the upholstery 14 (artificial or natural leather can also be used if breathability is not required).

[0042] 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 in. 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 in downward. 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 in downward. This allows the front-to-back position of the front end of the seat 2 to be adjusted. 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.

[0043] 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.

[0044] As shown in Figure 3, the lower surface of the shell member 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.

[0045] 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.

[0046] (2) Upholstery retraction structure of the first embodiment For example, as shown in Figures 2(A) and 2(C), the seat 2 has a shape that is indented upward when viewed from the front and is deeper at the rear when viewed from the side, and the seat inner shell 12, cushioning material 13 and upholstery 14 also have a similar shape. The rear end has raised corners on both sides, and therefore the rear of the seat 2 is significantly indented upward. Then, at the point where the seat 2 is significantly indented (roughly the front and rear position where the seated person's tailbone makes contact), there are long, retractable sections 23 that extend to the left and right.

[0047] The base layer of the cushioning material 13 is composed of a three-dimensional mesh structure made by intertwining and bonding countless elastic and bendable resin fibers, such as polyester fibers. Therefore, it has a breathable structure. On the other hand, the buffer layer 16 is made of hardened felt material with intertwined thin resin fibers, providing breathability while offering a soft feel to the buttocks and thighs of the person sitting on it.

[0048] As shown in Figure 6(A), the cushioning 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 circumference 16a of the cushioning layer 16 is set to extend beyond the base layer 15 and wrap around to the outside of the seat inner shell 12. Since the cushioning layer 16 deforms under compression against elasticity, the upholstery 14 is held taut when the cushioning layer 16 is compressed and attached to the seat inner shell 12.

[0049] As shown in Figures 4-6, a single string-like material 24, as an example of a tensioning material as described in the claim, is placed in the part of the buffer layer 16 corresponding to the pull-in portion 23. The string-like material 24 is, for example, a round string, and is pulled out downwards through the buffer layer 16 at both the left and right ends of the buffer layer 16. Furthermore, the left and right downward-facing portions 24a of the string-like material 24 are pulled out below the seat inner shell 12, passing through the base material layer 15 and the seat inner shell 12, and as shown in Figures 3, 5, and 6, the left and right downward-facing portions 24a are bound together at the lower surface of the seat inner shell 12.

[0050] 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 buffer layer 16 by strongly pulling the downward portion 24a of the cord-like material 24. The upholstery fabric 14 is then sewn to the upper surface of the buffer layer 16 at the location of the retraction section 23 by sewing. In Figures 2(C) and 6(E), the threads exposed by the sewing are indicated by the symbol 23a.

[0051] Furthermore, the upholstery 14 can be sewn only to the surface of the cushioning layer 16, or it can be sewn by piercing the cushioning layer 16 with a sewing machine needle and holding the upholstery 14 and the cushioning layer 16 together with sewing thread. Alternatively, a strip of fabric can be sewn to the upper surface of the cushioning layer 16 as a reinforcing material, and the upholstery 14 can be sewn to this strip of fabric. In addition, a cord-like material 24 can be secured to the upper surface of the cushioning layer 16 using a method such as overcast stitching, and the upholstery 14 can be sewn to this cord-like 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-like material 24 through.

[0052] It is also possible to attach a plug to the entry hole 25 to press the downward portion 24a of the string-like material 24 against it. For example, a push rivet can be used as the plug. Figures 6(C) and 6(D) show holes 26 in the buffer layer 16 through which the string-like material 24 passes, but these are for convenience only and the holes 26 are not necessary.

[0053] (3) Summary of the first embodiment The seat 2 is manufactured (assembled) in the following steps: the upholstery 14, the cushioning layer 16, the base layer 15, and the seat inner shell 12 are manufactured separately, and first, the string-like material 24 is attached to the cushioning layer 16. In this case, although the drawing shows one string-like material 24 being used, if one string-like material 24 is used, it is sufficient to simply insert the downward-facing portion 24a into the cushioning layer 16, and it is not necessarily required to fix the string-like material 24 to the cushioning layer 16.

[0054] On the other hand, it is also possible to use two string-like materials 24, in which case the upper ends of the left and right string-like materials 24 need to be fixed to the upper surface of the buffer layer 16. In order to form a groove-shaped indentation 23 in the buffer layer 16, it is preferable to use one string-like material 24 and use the string-like material 24 to recess the buffer layer 16 downwards. The string-like material 24 needs to be inserted through the buffer layer 16, and the string-like material 24 can also be inserted by using a needle-shaped jig such as a sewing needle to pierce the buffer layer 16 and pull it out.

[0055] Alternatively, the buffer layer 16 can be spread open with a funnel-shaped jig, and the string-like 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 buffer layer 16 and the base layer 15 to the jig and use a mask or the like to accurately insert the string-like material 24 into the predetermined position.

[0056] After attaching the string-like material 24 to the cushioning layer 16, the upholstery 14 is placed on top of the cushioning layer 16 in a precisely positioned position, and then, as shown in Figure 6(E), the upholstery 14 is fixed to the cushioning layer 16 by sewing the area of ​​the retraction portion 23. Next, with the downward-facing portion 24a of the string-like material 24 inserted through the base layer 15 and the seat inner shell 12, the upholstery 14 is placed over the cushioning 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 string-like 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.

[0057] 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 buffer layer 16 is made of a dense and soft-touch material like felt, so it is soft against the seater's buttocks and thighs and provides excellent comfort. Moreover, 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. In particular, by using a material in which the fibers are woven in the longitudinal direction (the direction in which the base layer 15 and the buffer layer 16 are stacked) for the buffer layer 16, the cushioning properties of the buffer layer 16 can be improved, and the unevenness of the base layer 15 can be made less noticeable to the seater. Specifically, V-lap (registered trademark) manufactured by Teijin Limited is an example of such a material.

[0058] Furthermore, because it has a retractable section 23, even if the seat 2 has a highly three-dimensional shape with a large recess in the upper surface of the rear, 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 the 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 held in a state overlapping the buffer 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.

[0059] In this embodiment, since the string-like material 24 is attached to the buffer layer 16, the buffer layer 16 is attached to the base layer 15 in a precisely positioned state, while the upholstery 14 is pre-fixed to the buffer layer 16, so the buffer layer 16 is also attached to the base layer 15 in a precisely positioned state. Furthermore, since the upholstery 14 is pre-attached to the buffer layer 16, the assembly work can be carried out quickly.

[0060] The thickness of the base layer 15 and the buffer layer 16 can be arbitrarily set according to the characteristics of the unit in question. However, when applied to the seat 2 as in the embodiment, setting the base layer to a thickness of several centimeters (for example, 2 to 5 centimeters) and the buffer layer to a thickness of several millimeters to over ten millimeters is preferable because it ensures a soft touch while securing the necessary cushioning and durability for the seat 2.

[0061] As described above, by wrapping the outer periphery 16a of the cushioning layer 16 around the outside of the seat inner shell 12, the elastic deformation of the cushioning layer 16 can be used to hold the upholstery 14 in an upholstered state, thus maintaining a beautiful appearance. Furthermore, the upholstery 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.

[0062] 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. Furthermore, it is possible to make the locations where the string-like material 24 is attached to the cushioning layer 16 different from the locations where the upholstery 14 is sewn, and it is also possible to attach the upholstery 14 to the cushioning layer 16 at locations on both the front and rear sides of the attachment points for the string-like material 24 to the cushioning layer 16.

[0063] In this embodiment, the bending deformation allowable 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 that overlaps with the uneven portion of the seat inner shell 12. Alternatively, it is possible to form the lower surface of the base material layer 15 into an uneven shape that interlocks with the uneven portion of the seat inner shell 12. The base material layer 15 can be made by cutting out commercially available sheet material, but thinning it and forming the lower surface into an uneven shape can be achieved by heating and pressing it.

[0064] (4) Other embodiments Figure 7 shows other embodiments as modified examples. In the second embodiment shown in (A), long grooves 27 are pre-formed by pressure on the surface of the buffer layer 16. In the third embodiment shown in (B), the retraction portions 23 are formed in a point-like manner, and multiple retraction portions 23 are formed. A string-like material 24 is attached to the retraction portions 23 via a stopper. Although the figure is different, it is also possible to form multiple line-shaped retraction portions 23.

[0065] In the fourth embodiment shown in (C), a narrow resin tape 28 is placed on the buffer layer 16, and the resin tape 28 is pulled downward by a string-like material 24. In this case, the upholstery 14 is sewn to the resin tape 28. The fifth embodiment shown in (D) is a modification of the fourth embodiment, in which a long groove 27 is formed in the buffer layer 16 in advance, and the resin tape 28 is placed in the long groove 27. In all embodiments, the resin tape 28 can be pulled downward by three or more string-like materials 24.

[0066] In the sixth embodiment shown in (E)(F), a resin tape with feet 29 is used as a tensioning material. Specifically, the resin tape with feet 29 has a strip portion 30 and a plurality of pairs of feet 31 provided on its longitudinal side edge, and the feet 31 penetrate the buffer layer 16, the base material layer 15, and the seat inner shell 12. At least the downward-facing exposed portion of the feet 31 is formed as a sawtooth-shaped interlocking portion 31a, and a catch 32 is fitted into the interlocking portion 31a from below to hold the resin tape with feet 29 in a state of being pulled downward.

[0067] The catch 32 has a ratchet structure that engages with the engagement portion 31a, and is designed so that it can be pushed against the engagement portion 31a but cannot be retracted. Therefore, by pulling the engagement portion 31a while the catch 32 is in contact with the lower surface of the seat inner shell 12, the cushioning layer 16 can be maintained in a compressed and deformed state. The upholstery 14 is sewn to the strip portion 30 of the resin tape 29 with legs.

[0068] Inserting the foot portion 31 into the buffer layer 16 and the base layer 15 can be done using a jig that is inserted into the buffer layer 16 and the base layer 15 from below, or by utilizing the rigidity of the foot portion 31. In the latter case, if pilot holes are made in the buffer layer 16 and the base layer 15 using an awl-shaped piercing tool, insertion can be done easily while maintaining accurate positioning. Instead of using the dedicated footed resin tape 29, it is also possible to use a strip-shaped resin tape 28 in combination with a commercially available resin fastener.

[0069] In the seventh embodiment shown in (G), the upholstery 14 is also sewn to the buffer layer 16 at the location of the auxiliary stitching portion 33, which is different from the retraction portion 23 (the auxiliary stitching portion 33 can be viewed as part of the retraction portion). In this embodiment, the integration between the upholstery 14 and the buffer layer 16 is enhanced, improving the function of preventing the upholstery 14 from shifting.

[0070] Now, when retractable sections are provided in the seat or backrest, care is taken to make these sections as inconspicuous as possible. Therefore, if stitching is used to construct the retractable sections, the stitching will be the same color as the upholstery 14. On the other hand, variations in the upholstery of the seat or backrest are sometimes used as a way to enhance the commercial value of a chair, and a concrete example of this is providing upholstery in multiple colors. However, simply changing the color scheme is unlikely to attract the attention of consumers.

[0071] In this regard, by providing an auxiliary stitching section 33 as in the seventh embodiment, the thread used in the auxiliary stitching section 33 can be made to be a conspicuous color different from the upholstery fabric 14, thereby making the auxiliary stitching section 33 function as a stitch pattern, strongly attracting the consumer's attention and improving the product's value. Therefore, the auxiliary stitching section 33 can adopt various forms by disregarding its retraction function.

[0072] For example, it can be used to create various shapes, or to apply company names, logos, trademarks, and product names like embroidery for promotional purposes. If there are many seats, it can also function as seat numbers by displaying numbers with stitching. In any case, since it is not printed, there is no problem with color fading with use, and it can maintain a high level of design quality.

[0073] From a design perspective, the cushioning layer 16 is not necessarily required, and a structure in which the threads are sewn onto the upholstery 14 in an embroidered state can also be adopted (however, sewing them onto the cushioning layer 16 is preferable in that it can prevent the upholstery 14 from shifting or deforming). Using threads of different colors is preferable because it enhances the function of the pattern.

[0074] (5) Substrate layer of the eighth embodiment Figures 8-12 show the eighth 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, cushioning layer 16, and base material layer 15 employ different configurations than those of the first embodiment. The materials and basic functions of each element are the same as those of the first embodiment.

[0075] One characteristic of this embodiment is the shape of the outer periphery of the base layer 15. Specifically, as clearly shown in Figures 12(A) and 12(B), the outer periphery surface 15a of the base layer 15 is curved to have a rounded shape. In addition, a flange 35 is formed in the middle of the thickness direction.

[0076] Figure 10 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 10(B), to form a three-dimensional shape and remove excess material. In other words, the inner edges of the pair of press dies 37 and 38 are used as cutting blades, allowing for three-dimensional molding and punching to be performed as a series of processes. The press dies 37 and 38 are brought as close together as possible, leaving a gap between the inner edges of both press dies, thereby forming the flange 35.

[0077] 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 surface 15a is curved, the pressure from the press molds 37 and 38 acts on it, making it easy to soften the wire group (resin fiber group) and form a smooth surface. And because the outer surface 15a is a smooth surface, there are no problems such as the wire (resin fiber) of the material fraying or pieces falling off.

[0078] The outer 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 used. 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.

[0079] 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.

[0080] 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 into a positioning pin provided on the seat inner shell 12. As can be seen from Figures 12(A) and (B), because the flange 35 is rigid, it tends to bite into the buffer layer 16. Therefore, the flange 35 also functions as a means of preventing displacement between the buffer layer 16 and the base material layer 15.

[0081] As can be seen from the comparison between Figure 12(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.

[0082] (6) Buffer layer of the eighth embodiment As clearly shown in Figures 12(A) and (B), the outer periphery 16a of the cushioning 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 periphery 16a of the cushioning layer 16 around the rear end of the seat inner shell 12. However, it is possible to wrap the cushioning layer 16 towards the lower surface of the seat inner shell 12 even at the rear end of the seat inner shell 12.

[0083] Now, if the cushioning layer 16 is wrapped around the seat inner shell 12 at three edges—the left and right sides and the front end—and the cushioning 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 is unsightly. Furthermore, assembling the cushioning layer 16 is cumbersome.

[0084] Therefore, in this embodiment, the buffer layer 16 is pre-formed into a tray shape and fitted into the base layer 15. That is, as shown in Figure 12(C), when punching out the buffer 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 buffer layer 16 is formed into a tray shape by raising the side portion 16b and the front portion 16c and sewing their ends together.

[0085] As described above, when the cushioning 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 its tray shape, the corners are angular, but when the upholstery 14 is covered, the front corners of the cushioning layer 16 deform to match the front corners of the seat inner shell 12, maintaining a wrinkle-free (uneven) state.

[0086] As shown by the dashed line in Figure 12(C), by forming a notch 39 at the rear of the buffer layer 16, it is possible to form the buffer layer 16 in a tray shape with walls around its entire circumference. In this case, since the buffer layer 16 completely covers the base layer 15 around its entire circumference, relative lateral displacement (slippage) between the buffer layer 16 and the base layer 15 can be reliably prevented.

[0087] (7) Upholstery and retractable structure of the eighth 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 11, a number of circumferentially arranged edge hook-shaped claws 22a 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.

[0088] As shown in Figures 12(A) and 11, the upholstery 14 also has a pocket portion 14a that covers the bending deformation allowance 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 11, 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 allowance portion 12a of the seat inner shell 12 is abstracted away and shown as a blank space.

[0089] 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.

[0090] Similar to the first embodiment, the upholstery 14 is pre-sewn to the buffer layer 16 at the retractable portion 23. In Figure 9, 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 (string-like material). The base end (upper end) of each strip of fabric 41 is sewn to the lower surface of the buffer layer 16. Alternatively, the strips of fabric 41 can be attached to the upholstery 14 and passed through the buffer layer 16. Alternatively, the strips of fabric 41 can be sewn to the upper surface of the buffer layer 16 and passed through the buffer layer 16 and pulled downwards. In any case, it is preferable to sew the strips of fabric 41 to the upholstery 14 as well.

[0091] 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 locked into 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.

[0092] As clearly shown in Figure 11, 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 11, 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 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 claw 22b located on the outside in the left-right direction.

[0093] 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 performed 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.

[0094] (8) Positioning member of the second embodiment As shown in Figure 9, fabric side positioning members 44 are sewn to the lower left and right side portions of the cushioning layer 16, and rear positioning members 45 are sewn to the lower left and right rear portions of the cushioning layer 16. The side positioning members 44 and rear positioning members 45 are examples of positioning means that hold the cushioning layer 16 in a non-shifting manner relative to the seat inner shell 12. However, since the base material layer 15 is held in place by the cushioning 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.

[0095] The strap fabric 41 and the rear positioning member 45 are sewn to the cushioning layer 16 and the upholstery 14. In other words, the strap fabric 41 and the rear positioning member 45 are sewn together with the cushioning layer 16 and the upholstery 14 as a single unit. At the location of the sewn section 40 shown in Figure 10(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.

[0096] 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 9) formed in them.

[0097] As clearly shown in Figures 11 and 12(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.

[0098] 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 44 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.

[0099] 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 buffer 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.

[0100] 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 buffer layer 16, but as in the embodiment, sewing them to the lower surface of the buffer 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.

[0101] 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 cushioning 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 cushioning 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.

[0102] (9) Other inventions In the eighth embodiment, a novel structure that can be claimed is disclosed for a body support unit for a chair, such as a seat. This point will be explained next.

[0103] (10). Background technology Now, while foamed polyurethane is often used as cushioning material for chair seats and backrests, it has several drawbacks, including poor breathability, not always high elasticity, and a tendency to sag over time due to a decrease in its elastic recovery ability.

[0104] On the other hand, there are three-dimensional mesh structures formed by intertwining and bonding highly elastic resin fibers. These mesh structures offer excellent breathability, high resilience, and durability. By selecting the thickness and density of the fibers, a considerably soft feel can also be achieved. Focusing on this point, prior art document 1 discloses a two-layer structure in which a cushioning material made of a three-dimensional mesh structure is composed of a tough base layer made of thick fibers and a soft buffer layer made of finely intertwined fibers, with the two layers heat-fused together.

[0105] Public document 2 discloses a cushioning material having a three-dimensional mesh structure and a vertical nonwoven fabric. The support structure of the cushioning material and the structure of the upholstery are unknown.

[0106] Publicly available document 1: Japanese Patent Publication No. 2025-34936 Publicly available document 2: International Publication WO2021 / 177226

[0107] (11) Problems the invention aims to solve: Overview Three-dimensional mesh structures made from highly elastic resin fibers are widely used in mattresses and other applications. As shown in Public Document 1, while constructing the buffer layer with thin fibers can soften the feel, it is currently difficult to achieve the same level of softness as a urethane cushion. In contrast, as shown in Public Document 2, using a vertical nonwoven fabric for the buffer layer can achieve a soft feel, but constructing the cushioning material with a laminated structure of different materials makes it prone to problems related to assembly work and inter-layer slippage.

[0108] The invention disclosed in the eighth embodiment was made to improve this situation.

[0109] (12) Means and effects for solving the problem

[0110] Another invention in the eighth embodiment focuses on a body support unit for a chair. Typical body support units include a seat and a backrest, but the seat is particularly preferred. This is because the seat is subjected to heavy loads repeatedly and also requires a soft feel.

[0111] a: Common configuration The chair body support unit disclosed in claim 8 has three features, but a common configuration is: "It has a synthetic resin seat inner shell 12 with one side being a pressure-receiving surface, a cushioning material 13 that overlaps the pressure-receiving surface of the seat inner shell 12, and upholstery 14 that covers the cushioning material 13." The cushioning material 13 is a body support unit for a chair, composed of a laminate of a base layer 15 with high elastic strength and a sheet-like buffer layer 16 that is thinner and softer than the base layer 15 and of equal thickness. The base layer 15 consists of a three-dimensional mesh formed by intertwining a group of curved synthetic resin elastic fibers, while the buffer layer 16 consists of a nonwoven fabric-like material, felt material, or knitted fabric having a group of fibers extending in the thickness direction. The buffer layer 16 directly overlaps the base material layer 15, and the periphery 16a of the upholstery 14 is wrapped around the shell member. It includes the following basic structure.

[0112] Furthermore, since felt is also a type of nonwoven fabric, a "nonwoven fabric-like material or felt material having a group of fibers extending in the thickness direction" can be called a "vertical nonwoven fabric." For the three-dimensional mesh structure, thermoplastic resin materials are preferred from the viewpoint of weldability, polyester resins are preferred from the viewpoint of elasticity and resistance to repeated loads, and elastomers are preferred from the viewpoint of softness to the touch.

[0113] The fibers constituting the three-dimensional network include both structures where the entire structure is made of elastomer-based material and structures where the core material is covered with an elastomer layer. Since the three-dimensional network is formed by heat welding (fusion) numerous fibers at their contact points, a composition that allows for heat welding at the lowest possible temperature is preferable. 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.

[0114] In the basic configuration, the buffer layer 16 is directly superimposed on the base layer 15, resulting in a simple structure and easy unit assembly. In this basic configuration, nonwoven fabric, felt, or knitted fabric is soft against the body, so even in elements that come into strong contact with the body, such as a seat, a soft feel similar to that of a urethane cushion can be achieved.

[0115] By covering the entire surface of the base layer 15 with the buffer layer 16, a soft feel can be achieved regardless of which part of the body support unit a person's body touches. Furthermore, since the upholstery 14 overlaps the entire surface of the base layer 15 via the buffer layer, covering the entire surface of the base layer 15 with the buffer layer 16 allows the upholstery 14 to be held taut by utilizing the softness of the buffer layer 16. Consequently, it has a good appearance.

[0116] Furthermore, since commercially available uniform-thickness sheets can be used for the base layer 15 and the cushioning layer 16, manufacturing costs can be reduced. In addition, although the base layer 15 has high elastic strength and durability, even if the base layer 15 is formed into a three-dimensional shape to fit the user's body, it can be accurately attached to the seat inner shell 12 while also ensuring a good fit to the user's body.

[0117] Furthermore, although the cushioning layer 16 is a sheet of uniform thickness, it is highly flexible, so it can adhere closely to the base layer 15 even if the base layer 15 has a three-dimensional shape. Therefore, integration with the base layer 15 can be ensured, providing the user with a soft touch. In addition, since both the cushioning layer 16 and the base layer 15 are breathable, if fabric is used as the upholstery 14, breathability can be ensured for the entire body support unit, preventing stuffiness. On the other hand, in the basic configuration, natural or artificial leather can also be used as the upholstery 14, and in this case as well, since the cushioning material 13 has high heat dissipation properties, stuffiness can be prevented or significantly reduced.

[0118] b: 1st and 2nd separate inventions The first separate invention, based on a common configuration, "The base material layer 15 is a processed product formed by heating and pressurizing a material 36 of equal thickness, and the outer peripheral surface 15a of the base material layer 15 is formed as a smooth surface that narrows outward in cross-sectional view." This is the structure.

[0119] In this first separate invention, since the base layer 15 maintains its shape, the material fibers are prevented from unraveling, thereby stabilizing and improving quality. Because the outer peripheral surface 15a of the base layer 15 has a tapered cross-sectional shape, the outer periphery of the unit is prevented from becoming angular, resulting in a smooth profile. Therefore, it not only looks good but also ensures a soft feel against the user's body. Furthermore, since it can be easily processed using commercially available materials of equal thickness in sheet or block form, it also has the advantage of reducing costs.

[0120] As an example of development of the first alternative invention, a second alternative invention can be presented. This second alternative invention is based on the first invention, "A flange 35 is formed on at least a portion of the outer circumference of the base material layer 15." This is the configuration that is being adopted.

[0121] In the second alternative invention, the excess portion can be cut while the flange 35 is held in place by a pair of press dies 37 and 38, allowing for a smooth series of processes from molding to cutting. Furthermore, it offers excellent shape stability. Additionally, because the outer circumference is maintained by the flange 35, the outer circumference does not expand due to springback, resulting in superior reliability. Due to the high rigidity of the flange 35, it is also possible to improve the positioning effect by pressing it against the wall of the seat inner shell 12.

[0122] Alternatively, the flange 35 can be used for positioning when setting the base layer 15 onto the inner shell 12. For example, a notch can be formed on the flange to serve as a marker, a notch can be formed on the flange to fit onto a projection formed on the shell member, or an engagement hole can be formed on the flange to fit onto a pin protruding from the shell member.

[0123] d: 3rd to 5th alternative inventions The third invention, which is an independent item based on the basic configuration, "The buffer layer 16 is provided with positioning members 44 and 45 that are wrapped around the back side of the seat inner shell 12 and connected to the seat inner shell 12." This is the configuration that is being adopted.

[0124] This third alternative invention provides the effect of holding the buffer layer 16 and the base material layer 15 in predetermined positions. Furthermore, since the positioning members 44 and 45 are of a non-penetrating type, connection to the seat inner shell 12 is easy.

[0125] As an example of the development of the third separate invention, in the fourth separate invention, "The positioning member 44 is provided on two sides of the buffer layer 16 that are located on opposite sides of the center." This configuration is adopted. Furthermore, as an example of the development of the third or fourth separate invention, in the fifth separate invention, "The positioning members 44 and 45 are made of cloth or other flexible thin sheet material." This is the configuration that is being adopted.

[0126] In the fourth alternative invention, the buffer layer 16 is pulled to both the left and right sides, thus exhibiting a high positioning effect. While strings can also be used as positioning members, using a thin sheet material as a positioning member, as in the fifth alternative invention, allows the positioning members 44 and 45 to be connected over a wide area of ​​the buffer layer, resulting in a high anti-slip effect and excellent strength.

[0127] Taking the seat as an example, in the fourth alternative invention, the positioning member 44 is attached to the left and right sides of the buffer layer, but in addition to this (or instead), it is possible to provide a positioning member 45 to the rear or front of the buffer layer 16.

[0128] In seats with a downward-sloping seat surface, the rear of the upholstery is pulled downward to prevent it from lifting. However, it is possible to sew the front end of a positioning member 45, made of a flexible thin sheet, to the cushioning layer 16 and the upholstery at the point where it is pulled in. In this case, the positioning member 45 is also sewn to the upholstery 14, which improves the mounting strength of the positioning member 45. The pulling function can also be improved.

[0129] e: 6th-7th Alternative Inventions Furthermore, the eighth embodiment discloses a sixth alternative invention as an independent term based on the common configuration. The sixth alternative invention, in the common configuration, "The buffer layer 16 is formed in the shape of a tray with walls, and the walls form a wrapped portion 16a that covers the outer circumference of the base material layer." This is the structure.

[0130] In this sixth alternative invention, the buffer layer 16 is pre-formed in a tray shape, resulting in a high holding effect on the base layer 15 and excellent slip prevention. Furthermore, the buffer layer 16 can be attached to the base layer 15 precisely with a touch, allowing for accurate and easy assembly of the body support unit. In addition, since no wrinkles form at the corners of the buffer layer 16, the upholstery 14 remains taut, resulting in a good appearance.

[0131] In this embodiment, the front portion 2a of the seat 2 serves as a depth adjustment means for the seat 2, and therefore, the front portion of the base material layer 15 also serves as a deformation-tolerant portion. In this case, however, the front portion of the base material layer 15 must be firmly held by the buffer layer 16. As a means of firmly holding the front portion (especially the front corner portion) of the base material layer 15 with the buffer layer 16, the seventh alternative invention, which is an extension of the sixth alternative invention, can be used.

[0132] In other words, the seventh separate invention is, in the sixth separate invention, "The shell member is a seat inner shell 12, and the front part of the seat shell member 12 and the base material layer 15 is formed as a curlable, deformation-allowing portion 12a, The buffer layer 16 has a front wall and side walls that cover the deformation-allowable portion of the base material layer 15, and these are formed in a continuous manner. This configuration is specified.

[0133] In this seventh alternative invention, since the front wall and side wall of the buffer layer 16 are continuous, even if the base layer 15 and the buffer layer 16 are entangled, stretched, or deformed, the laminated state of the buffer layer 16 and the base layer 15 can be firmly maintained. Each of these alternative inventions can also be applied to backrests, but the front-to-back direction can be replaced with the up-and-down direction.

[0134] (13) Others Although embodiments of the present invention have been described above, the present invention can be materialized in various other 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.

[0135] The base layer may consist of multiple layers. The buffer layer does not need to be placed across the entire surface of the base layer; it may be placed only where the seated person's body pressure acts. The tensioning material can also be made of metal (for example, sheet metal such as aluminum plate).

[0136] It is also possible to temporarily fix the buffer layer to the base layer by adhesive or other means. In this case, it is possible to temporarily fix the buffer layer to the base layer and then attach the upholstery to the buffer layer, or to attach the upholstery to the buffer layer first and then temporarily fix the buffer layer to the base layer. The base layer does not necessarily have to be a three-dimensional mesh. In addition, the buffer 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. [Industrial applicability]

[0137] 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. [Explanation of Symbols]

[0138] 2nd seat 2a Front section (part that allows for winding deformation) 3 Backrest 6,7 Tilting frame 8 Outer shell 12. Shell component (seat inner shell) 12a Allowable bending deformation section 13 Cushioning material 14 Upholstery 15 Base material layer 15a Outer surface 16 Buffer layer 17 Downward-facing bracket 18 Slider 18a Catch section 22, 22a, 22b Hook-shaped claws for securing upholstery 23. Entrance section 24. String-like material as an example of a tensioning material. 24a Downward portion 25 Receiving hole 41. A strip of cloth (cloth cord) as an example of a tensioning material.

Claims

1. It has a shell member through which the weight of the seated person acts via a cushioning material, and upholstery covering the cushioning material. The upholstery is provided in a body support unit for a chair, which has a retractable section that is pulled toward the shell member, The cushioning material has a laminated structure consisting of a highly elastic base layer placed on the side of the shell member and a low-elasticity buffer layer placed between the base layer and the upholstery. The upholstery is connected to the buffer layer at the location of the retraction section, and the buffer layer is pulled toward the shell member via a tensioning member at the location of the retraction section. A chair's body support unit.

2. The base layer and the buffer layer are breathable. A body support unit for a chair as described in claim 1.

3. The base layer is a three-dimensional mesh formed by bonding together a group of curved synthetic resin elastic fibers, and the buffer layer is a nonwoven fabric, felt, or knitted fabric formed by solidifying a group of fine fibers in an intertwined state. A body support unit for a chair as described in claim 2.

4. The upholstery is sewn to the buffer layer, The tensioning member is a string-like material, and one end of the string-like material is positioned on the surface portion of the buffer layer that overlaps with the upholstery or on the back portion that overlaps with the base material layer, and is sewn integrally with the buffer layer and the upholstery. The other end of the string-like material is pulled out to the back side of the shell member. A body support unit for a chair as described in any one of claims 1 to 3.

5. The aforementioned shell member is a seat inner shell, The aforementioned retractable portion is formed in a straight line shape extending horizontally from left to right, towards the rear. The front portion of the shell member and cushioning material can be rolled down. A body support unit for a chair as described in claim 2 or 3.

6. The aforementioned shell member is a seat inner shell or a back inner shell. The buffer layer is thinner than the base layer. A body support unit for a chair as described in claim 1 or 2.

7. A method for manufacturing a body support unit for a chair, wherein a cushioning material consisting of a base material layer and a buffering layer is held on one side of a shell member via upholstery, and the upholstery is provided with a retractable portion that fits into the cushioning material side, The process involves preparing the shell member, base material layer, buffer layer, upholstery, and pull-in cord-like material. The process involves sewing the string-like material, the cushioning layer, and the upholstery together as a single unit, with the string-like material largely exposed on the back side of the cushioning layer. The process of inserting the string-like material into the base material layer and the shell member, The process includes the step of securing the string-like material to the shell member while it is being pulled taut, A method for manufacturing a body support unit for a chair.

8. The tensioning member is a string-like material inserted through a through hole made in the shell member, and the tip of the string-like material is hooked onto a hook-shaped claw provided on the shell member. A body support unit for a chair as described in any one of claims 1 to 3.

9. The shell member has numerous slits that allow it to stretch and deform under the user's load, and one of these slits is used as a through-hole for inserting the string-like material. A body support unit for a chair as described in claim 8.

10. Numerous hook-shaped claws are formed on the back surface of the shell member for temporarily fastening the upholstery, and these hook-shaped claws are used to temporarily fasten the upholstery as hook-shaped claws for securing the string-like material. A body support unit for a chair as described in claim 8.

11. At the location of the hook-shaped claw to which one string-like material is secured, the end of the string-like material is covered with the upholstery, and the upholstery is fixed to the shell member with a stapler. A body support unit for a chair as described in claim 10.

Images