Chair seat structure

Abstract

To provide a chair seat structure that can improve seating comfort. [Solution] The structure of the chair seat 4 includes a seat inner shell 7, a seat cushion material 8 disposed on the upper surface of the seat inner shell 7, a surface material 10 covering the seat cushion material 8, and a seat support member 6 that supports the seat inner shell 7. A lower cushion material 9 is disposed between the seat inner shell 7 and the seat support member 6.

Description

Technical Field

[0001] The present invention relates to a seat structure of a chair, and more particularly to a seat structure of a chair including a seat inner shell, a seat cushion material disposed on the upper surface of the seat inner shell, a skin material covering the seat cushion material, and a seat receiving member supporting the seat inner shell.

Background Art

[0002] As a means for ensuring comfort when sitting on the seat of a chair, it is common to dispose a sponge-like cushion material on the seat board (see, for example, Patent Document 1). For example, Patent Document 1 discloses a chair having a seat surface provided with a seat cushion material on a seat inner shell. In the chair of Patent Document 1, a plurality of cushioning slits are provided in the seat inner shell to bend the seat inner shell itself, thereby improving the cushioning of the seat.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional seat structure of a chair, when a large load is applied to the seat surface when the user sits down, the seat inner shell may be greatly deformed and contact the lower member, resulting in bottoming, and there is room for improvement in sitting comfort.

[0005] The present invention has been made to improve such a situation, and an object thereof is to provide a seat structure of a chair that can improve sitting comfort.

Means for Solving the Problems

[0006] The present invention relates to a chair seat structure comprising a seat inner shell, a seat cushion material disposed on the upper surface of the seat inner shell, a surface material covering the seat cushion material, and a seat support member supporting the seat inner shell, wherein a lower cushion material is disposed between the seat inner shell and the seat support member.

[0007] According to the present invention, since a lower cushioning material is provided between the seat inner shell and the seat support member, cushioning can be improved, and bottoming out can be prevented even if the seat inner shell is significantly deformed, thereby improving seating comfort.

[0008] In the chair seat structure of the present invention, the seat support member may be provided with a receiving recess that accommodates at least a portion of the lower cushion material.

[0009] In this configuration, by arranging at least a portion of the lower cushioning material in a receiving recess provided in the seat support member, misalignment of the lower cushioning material relative to the seat inner shell and seat support member can be prevented.

[0010] Furthermore, the chair seat structure of the present invention may include a base body that supports the seat support member and a rocking mechanism housed inside the base body that supports the chair's backrest so that it can tilt backward, and the housing recess may be provided in a position that does not interfere with the rocking mechanism.

[0011] According to this configuration, the cushioning when sitting on a chair with a backrest that can be tilted backward can be improved, thereby improving seating comfort.

[0012] Furthermore, the receiving recess is provided at least below the seated person's buttocks, and the lower cushion material may be configured such that the thickness of the portion positioned below the seated person's buttocks is greater than the thickness of the other portions.

[0013] In this configuration, by increasing the thickness of the lower cushioning material in the area of ​​the seat where a large seating load is applied, the seating load can be reliably supported by the lower cushioning material, and the cushioning comfort when sitting can be improved.

[0014] Furthermore, in the seat structure of the chair according to the present invention, the lower cushion material may be provided in a replaceable manner.

[0015] This configuration allows users to choose their preferred level of cushioning by replacing the lower cushioning material, making it user-friendly. Furthermore, when the cushioning of the lower cushioning material deteriorates due to aging or other factors, the cushioning of the seat can be restored by replacing it with a new one. [Effects of the Invention]

[0016] The seat structure of the chair according to the present invention can improve seating comfort because a lower cushioning material is placed between the inner shell of the seat and the seat support member. [Brief explanation of the drawing]

[0017] [Figure 1] In this embodiment, (A) is a front view and (B) is a perspective view of the chair. [Figure 2] (A) is a top view of the chair, and (B) is a rear view. [Figure 3] (A) is a right side view of the chair, and (B) is a right side view of the chair in the rocking position. [Figure 4] This is a decomposed perspective view of the seat. [Figure 5] This is a plan view showing the seat support member and the rocking mechanism. [Figure 6] This is an exploded perspective view of the locking mechanism. [Figure 7] This is a longitudinal cross-sectional view at position AA in Figure 2(A). [Figure 8] This is a longitudinal cross-sectional view showing the locking state. [Figure 9] This is a longitudinal cross-sectional view showing the seated position.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Next, embodiments of the present invention will be described based on the drawings. In the following description, the terms "front and back" and "left and right" are used to specify directions. However, these terms of front and back and left and right are based on a seated person for the embodiment of the chair. The front view direction is the direction facing the seated person. Therefore, the left and right in the front view are opposite to the left and right as seen from the seated person.

[0019] (1) Overview of the chair First, the overview of the chair will be mainly described based on FIGS. 1 to 3. This embodiment is applied to a swivel chair frequently used for office work or the like. The chair has a leg support 1 and a leg device 2 having casters, a base body 3 fixed to the upper end of the leg support 1, a seat 4 disposed on the base body 3, and a backrest 5 on which a seated person can lean. The base body 3, the seat 4, and the backrest 5 are provided substantially symmetrically about the left and right.

[0020] The base body 3 is formed in a box shape that opens upward. The backrest 5 is provided in a substantially U-shaped opening facing forward so as to surround the rear edge portion of the seat 4 and the left and right seat side edge portions in a plan view, and includes a back plate portion 51 and left and right side plate portions 52. Although details will be described later, the backrest 5 is supported by the base body 3 so as to be tiltable backward.

[0021] (2) Overview of the seat For example, as shown in FIG. 4, the seat 4 includes a seat receiving member 6 made of a metal plate attached to the base body 3. A resin seat inner shell 7 is connected and supported to the seat receiving member 6. A seat cushion material 8 is stacked on the upper surface of the seat inner shell 7. The seat cushion material 8 is covered with a skin material 10 such as cloth.

[0022] The seat inner shell 7 is supported at its left and right edges by the seat support members 6, and its central part is configured to sink downward under the weight of the occupant. For example, the seat inner shell 7 is provided with numerous slits 7a so that it can flex freely according to the occupant's sitting posture. The arrangement area of ​​the slits 7a, as well as the shape and size of each slit 7a, can be changed as appropriate.

[0023] In this embodiment, the seat inner shell 7 is supported by the seat support member 6 via elastic bodies 11 (e.g., chrysalis or springs) provided at the four corners of the lower surface of the seat inner shell 7, and the seat inner shell 7 is provided so that it can tilt forward, backward, left and right in accordance with the weight shift when seated. However, the seat inner shell 7 can also be supported by the seat support member 6 without the interposition of elastic bodies 11.

[0024] A lower cushioning material 9 is provided between the seat inner shell 7 and the seat support member 6. The material of the lower cushioning material 9 is not particularly limited, but for example, recycled cushioning (chip urethane) or a three-dimensional mesh fiber structure can be used. The lower cushioning material 9 is housed in a receiving recess 61 provided at the rear of the central part of the seat support member 6. In this embodiment, the receiving recess 61 is provided at a location below the seated person's buttocks 100 (see Figure 9).

[0025] As shown in Figure 9, when a person sits on the seat 4, the seat cushion material 8 undergoes elastic compression deformation and the seat inner shell 7 sinks in, and the lower cushion material 9 undergoes elastic compression deformation in response. In this embodiment, the seat 4 undergoes elastic deformation of both the seat cushion material 8 and the lower cushion material 9 when seated, thus improving cushioning and preventing the seat inner shell 7 from bottoming out even if it deforms significantly, thereby improving seating comfort.

[0026] Furthermore, since the seat 4 can withstand the seating load with the lower cushioning material 9, the seat inner shell 7 can sink in well (become more prone to bending deformation), creating a comfortable seat that envelops the buttocks when seated. In addition, by appropriately selecting the elastic force of the lower cushioning material 9, the amount of compressive deformation of the lower cushioning material 9 when seated, i.e., the amount of sinking of the seat 4, can be controlled.

[0027] As shown in Figure 7, etc., in this embodiment, the upper surface 91 of the lower cushion material 9 (the contact surface with the seat inner shell 7) is slightly curved in a concave shape. By appropriately designing the shape of the upper surface 91 of the lower cushion, the shape of the seat inner shell 7 when seated can be controlled not only by the restorative force of the seat inner shell 7 itself but also by the restorative force of the lower cushion material 9, and the shape of the seat inner shell 7 when seated can be designed to be a desired shape.

[0028] In this embodiment, the seat support member 6 and the seat inner shell 7 are connected in a way that prevents detachment and allows for disassembly by fasteners such as screws (not shown). This makes it possible to replace the lower cushion material 9, allowing users to select their preferred level of cushioning by replacing the lower cushion material 9, thus making it user-friendly. Furthermore, when the cushioning of the lower cushion material 9 deteriorates due to aging or other reasons, the cushioning of the seat 4 can be restored by replacing the lower cushion material 9 with a new one.

[0029] (3) Overview of backrests As shown in Figures 3 and 7, the backrest 5 is connected to the base body 3 via a back connecting arm 12 and a back connecting member 13 so as to be able to tilt backward. As described above, the backrest 5 comprises a back plate portion 51 along the rear edge of the seat 4 and left and right side plate portions 52 along the left and right side edges of the seat 4. The lower end portion 51a of the back plate portion 51 and the lower end portion 52a of the side plate portions 52 are positioned at a height below the upper surface of the seat 4. In this embodiment, the lower ends 51a and 52a of the backrest 5 are curved inward from the side of the seat 4 diagonally downward and are positioned below the rear edge and left and right side edges of the seat 4.

[0030] Although detailed illustrations are omitted, the backrest 5 comprises a core material, a back cushion material covering at least the inward-facing surface of the core material, and a surface material such as cloth covering the entire surface of the backrest 5. A back connecting member 13 is fixed to the inward-facing surface of the lower end 51a of the backrest. The backrest 5 is supported by the base body 3 by the connection of the back connecting member 13 and the back connecting arm 12.

[0031] (4) Overview of the locking mechanism As shown in Figures 4 to 6, a rocking mechanism 20 for supporting the backrest 5 so that it can tilt backward is housed inside the metal base body 3. The base body 3 has a base body bottom 31 that is roughly rectangular in plan view, and left and right base body sides 32 that extend upward from the left and right edges of the base body bottom 31. An arm housing portion 33 for housing the back connecting arm 12 is recessed and bulges downward in the left-right center of the rear part of the base body bottom 31. A cylindrical leg support connecting portion 34 into which the upper end of the leg support 1 is inserted and fixed is provided integrally with the front surface of the arm housing portion 33 on the lower surface of the base body bottom 31.

[0032] The locking mechanism 20 is generally arranged symmetrically. The rear connecting arm 12, which constitutes a part of the locking mechanism 20, comprises a rear arm 12a extending in the left-right direction, a pair of forward-facing arms 12b extending forward from both ends of the rear arm 12a, and a connecting arm 12c extending in the left-right direction and connecting the intermediate parts of the left and right forward-facing arms 12b.

[0033] The rear arm 12a is made of metal and has a U-shaped cross-section with a downward-facing opening. The back connecting member 13 is connected to the upper surface of the rear arm 12a by fasteners such as screws. The forward arm 12b is formed of an upward-facing, roughly V-shaped metal plate, with its rear end fixed to the rear arm 12a and its front end rotatably connected to a support shaft 21 that extends in the left-right direction.

[0034] The support shaft 21 is made of a metal rod and is fixed to the base body 3 in a horizontal position by a support shaft fixing device 22 provided inside the arm housing portion 33 of the base body 3. The front part of the forward-facing arm 12b, which is pivotally supported on the support shaft 21, is located inside the arm housing portion 33, while the rear part of the forward-facing arm 12b and the rear arm 12a are located near the outside of the rear of the base body 3. The forward-facing arm 12b is positioned in an inclined position with the front lower and the rear higher. The rear connecting arm 12 is connected to the base body 3 so as to be rotatable around the support shaft 21.

[0035] The connecting arm 12c is made of metal and is provided in a roughly box shape with an upward opening. It is provided to be longer in the left-right direction than the distance between the left and right forward-facing arms 12b, and both left and right ends of the connecting arm 12c protrude outward from the left and right forward-facing arms 12b. The left and right side portions of the connecting arm 12c are provided with rear pin support portions 12d that extend upward. The rear pin support portions 12d have rear pin support holes 12e that open in the left-right direction for supporting the left and right inner ends of the rear pin member 23 that extends in the left-right direction.

[0036] Within the base body 3, a pair of left and right load-applying arms 24 extending in the front-rear direction are arranged along the side portion 32 of the base body. The load-applying arms 24 are made of metal and have a linear shape, extending from near the front edge to near the rear edge of the base body 3. The front half portion 24a of the load-applying arms 24 is provided with a roughly U-shaped cross-section with a downward opening, and the rear half portion 24b of the arms is provided as a pair of left and right plate-like structures extending rearward from the left and right side portions of the front half portion 24a, respectively.

[0037] The rear end of the rear half 24b of the arm is provided with a pair of left and right rear pin support holes 24c through which the rear pin member 23 is inserted, and is positioned on the left and right outer sides of the rear pin support portion 12d of the back connecting arm 12. By inserting the horizontally elongated rear pin member 23 through the rear pin support holes 12e and 24c and supporting it so that it cannot be removed, the load-applying arm 24 and the back connecting arm 12 are connected so that they can rotate relative to each other around the rear pin member 23.

[0038] A front pin member 25 extending in the left-right direction is horizontally mounted on the front half 24a of the load-applying arm 24, between the left and right side portions. Upward-facing convex load-applying arm connecting portions 35 are provided protruding from each of the left and right front corner portions of the base body bottom portion 31. The load-applying arm connecting portion 35 is made of metal and has a front pin support elongated hole 35a that opens in the left-right direction and extends in the front-rear direction. In this embodiment, the front pin support elongated hole 35a is formed of a resin or resin bushing member supported by the load-applying arm connecting portion 35.

[0039] The front half 24a of the load-applying arm 24 is placed over the load-applying arm connecting portion 35 from above, while the front pin member 25 is inserted through the front pin support elongated hole 35a. As a result, the load-applying arm 24 is supported with respect to the load-applying arm connecting portion 35 so as to be rotatable around the front pin member 25 and so as to be able to move back and forth. The front pin support elongated hole 35a restricts the range of movement of the load-applying arm 24 in the back and forth direction between a forward movement limit position where the front pin member 25 is positioned at the front end of the front pin support elongated hole 35a and a backward movement limit position where the front pin member 25 is positioned at the rear end of the front pin support elongated hole 35a.

[0040] The front half 24a of the left and right load-applying arms 24 are connected by a front spring support member 26 that extends in the left-right direction. The front spring support member 26 is formed, for example, from a metal rod, and both left and right ends are connected to the portion of the left and right front half 24a of the arms that supports the front pin member 25.

[0041] On the base body 3, at the bottom 31 of the base body, metal rear spring support members 27 are erected on the left and right sides of the base body, respectively, which in a plan view enclose the leg support connecting portion 34. Between the pair of left and right rear spring support members 27 and the front spring support member 26, a pair of left and right spring bodies 28 are arranged. The spring bodies 28 are for providing resistance to the backward tilting of the backrest 5, and in this embodiment, they are composed of compression coil springs arranged to be inclined in a front-high, rear-low posture along the front-rear direction. The spring bodies 28 are interposed in a compressed state between the front and rear spring support members 26 and 27, with their front ends abutting against the left and right edges of the front spring support member 26 and their rear ends abutting against the front surface of the rear spring support member 27.

[0042] As shown in Figure 7, the rocking mechanism 20 biases the front spring receiving member 26 forward by the elastic force of the spring body 28, thereby positioning the left and right load-applying arms 24 at their forward movement limit positions, and maintaining the backrest 5 in an upright position (initial position when unloaded).

[0043] As shown in Figure 8, when a seated person leans against the backrest 5 and a rearward load is applied to the backrest 5, the backrest connecting arm 12 and backrest connecting member 13 rotate downward around the pivot shaft 21. Then, the load-applying arm 24 connected to the backrest connecting arm 12 and the front spring-receiving member 26 fixed to the load-applying arm 24 rotate around the front pin member 25 and are pulled rearward, causing the spring body 28 to compress and deform. In this way, the rocking mechanism 20 supports the backrest 5 so that it can tilt backward against the elastic force of the spring body 28.

[0044] The range of backward tilt of the backrest 5 is limited by a front pin member 25 that is movable in the front-rear direction within the front pin support elongated hole 35a. As shown in Figures 1 to 3 and Figure 7, when the backrest 5 is in its initial position with no load, the lower end 52a of the side plate portion 52, which tilts backward together with the back plate portion 51, is located below the upper surface of the seat 4. Furthermore, even when the backrest 5 is in its maximum backward tilt position (see Figure 8), the lower end 52a of the side plate of the backrest 5 is configured to be located below the upper surface of the seat 4.

[0045] In other words, the backrest 5 is supported by the base body 3 so as to be able to tilt backward, such that the lower end 52a of the side plate portion does not remain above the upper surface of the seat 4 even when the backrest 5 changes its position. This prevents foreign objects from getting caught between the side plate portion 52 of the backrest 5 and the seat 4 when a person seated on the seat 4 tilts the backrest 5 backward, thus ensuring safety and making it user-friendly. In addition, when the backrest 5 is in its initial position without load, the lower end 52a of the side plate portion of the backrest 5 is positioned below the seat 4, making the base body 3 less visible when the chair is viewed from the side, thus providing a good appearance.

[0046] (5) Seat configuration As described above, the seat 4 comprises a seat support member 6, a seat inner shell 7, a seat cushion material 8, and a surface material 10 (see Figures 4 and 7, etc.). As shown in Figure 7, the seat cushion material 8 is made of an elastic material such as urethane and has a seat cushion recess 81 on its lower surface that accommodates the seat inner shell 7.

[0047] The seat cushion recess 81 is provided to a depth that accommodates the upper part of the base body 3 when the seat cushion material 8 is attached to the seat support member 6 with the seat inner shell 7 interposed therebetween. The seat cushion material 8 may be integrally molded with the seat inner shell 7 by insert molding, or the seat inner shell 7 may be housed and positioned in the seat cushion recess 81 after molding. Furthermore, the seat cushion material 8 is not limited to a molded product, but may be a sheet-like elastic material stretched over the seat inner shell 7.

[0048] As shown in Figures 4 and 5, the seat support member 6 is approximately rectangular in plan view and has a receiving recess 61 in the center for accommodating the lower cushion material 9. The receiving recess 61 is provided in the left and right center of the seat support member 6, extending from the front to the rear, with the first receiving recess 62 provided in the rear portion being deeper than the second receiving recess 63 provided in the front portion. The seat support member 6 has a shape in which the center of the front edge is cut out and the left and right front edge side ends 64 protrude forward, and the front edge of the receiving recess 61 is open toward the front.

[0049] As shown in Figures 7 and 8, the receiving recess 61 is provided in the seat support member 6 in a downwardly convex recess shape so as not to interfere with the locking mechanism 20. In this embodiment, the receiving recess 61 is provided extending from the front edge to the rear edge portion of the center of the seat support member 6 in the left-right direction. The first receiving recess 62, recessed in the rear edge portion, is provided above the arm receiving portion 33 at a depth that does not interfere with the back connecting arm 12. The second receiving recess 63, recessed in the front edge portion, is provided above the left and right spring bodies 28 and the space between them at a depth that does not interfere with the spring bodies 28.

[0050] In the seat 4, the first receiving recess 62 is located below the seater's buttocks 100 (see Figure 9). The second receiving recess 63 is located in the center of the seat 4, connected to the front of the first receiving recess 62. The seat support member 6 has openings 65 that open vertically on the left and right sides of the first receiving recess 62. The left and right openings 65 ensure ventilation between the seat cushion material 8 and the base body 3 through the slits 7a of the seat inner shell 7. At the four corners of the seat support member 6, there are downward-facing convex recesses 66 for positioning and supporting the elastic body 11 interposed between the seat support member 6 and the four corners of the seat inner shell 7.

[0051] As shown in Figures 4 and 7, the lower cushion material 9 housed in the housing recess 61 is approximately rectangular in plan view and comprises a first lower cushion portion 92 housed in the first housing recess 62 and a second lower cushion portion 93 housed in the second housing recess 63. The first lower cushion portion 92 is thicker than the second lower cushion portion 93. That is, the thickness of the first lower cushion portion 92, which is positioned below the seated person's buttocks 100 (see Figure 9), is greater than the thickness of the second lower cushion portion 93 (the other part). The left and right edges of the first lower cushion portion 92 housed in the first housing recess 62 are positioned to overlap the opening 65 without interfering with the rocking mechanism 20.

[0052] As described above with reference to Figure 9, when a person sits on the seat 4, the seat cushion material 8 undergoes elastic compression deformation and the seat inner shell 7 sinks in, and the lower cushion material 9 undergoes elastic compression deformation in response. In this embodiment, the thickness of the first lower cushion portion 92, which is positioned below the seater's buttocks 100, is greater than the thickness of the second lower cushion portion 93 (other parts). By increasing the thickness of the lower cushion material 9 in the area of ​​the seat 4 where a large seating load is applied, the seating load can be reliably supported by the lower cushion material 9, and the cushioning when seated can be improved.

[0053] The above describes specific examples of the present invention, but the present invention can be implemented in various other ways. For example, the lower cushioning material 9 may be made of an elastic material such as recycled cushioning material (chip urethane) or a three-dimensional mesh fiber structure, or it may be made of other elastic materials such as sliced ​​urethane, or it may be a configuration in which multiple elastic materials are laminated.

[0054] Furthermore, the lower cushioning material 9 comprises a first lower cushioning portion 92 and a second lower cushioning portion 93 which are integrally formed, but the first lower cushioning portion 92 and the second lower cushioning portion 93 may be provided separately. In this case, the first lower cushioning portion 92 and the second lower cushioning portion 93 may be made of different materials. Also, the shape of the lower cushioning material 9 can be changed as appropriate; for example, the lower cushioning material 9 may be formed with a uniform thickness. Also, the lower cushioning material 9 may be positioned so as to protrude from the receiving recess 61. Furthermore, the shape and depth of the receiving recess 61 can be changed as appropriate.

[0055] Furthermore, the shape of the seat 4 and backrest 5 can be arbitrarily set as needed. In addition, the rocking mechanism 20 can employ not only a compression coil spring as a means of providing resistance to the backward tilting of the backrest 5, but also various spring bodies (elastic bodies) such as torsion bars, leaf springs, and rubber, or a locking means such as a gas cylinder to control the backward tilting position of the backrest 5. Moreover, the seat structure of the chair of the present invention can be applied to chairs without a rocking function or a chair without a swivel function, and can also be applied to floor chairs without support legs. [Explanation of Symbols]

[0056] 3 Base 4 seats 5 Backrest 6. Seat support member 7-seat inner shell 8. Seat cushion material 9. Bottom cushioning material 10 Skin material 20 Locking Mechanism 61 Receiving recess 62 First accommodating recess 63 Second housing recess 91 Lower cushion top surface 92 First lower cushion section 93 Second lower cushion section 100 buttocks

Claims

1. The seat structure of a chair, It includes a seat inner shell, a seat cushion material disposed on the upper surface of the seat inner shell, a surface material covering the seat cushion material, and a seat support member that supports the seat inner shell, A lower cushioning material is provided between the seat inner shell and the seat support member. The seat structure of a chair.

2. The seat support member is provided with a receiving recess that accommodates at least a portion of the lower cushioning material. The seat structure of a chair according to claim 1.

3. The chair comprises a base body that supports the seat support member, and a rocking mechanism housed inside the base body that supports the chair's backrest so that it can tilt backward. The aforementioned receiving recess is provided in a position that does not interfere with the locking mechanism. The seat structure of a chair according to claim 2.

4. The aforementioned receiving recess is provided at least in a location below the seated person's buttocks, The aforementioned lower cushioning material has a greater thickness in the portion positioned below the seated person's buttocks compared to the thickness of other portions. The seat structure of a chair according to claim 2.

5. The aforementioned lower cushioning material is provided to be replaceable. A chair seat structure according to any one of claims 1 to 4.

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