Chair backrest

Abstract

We provide chair backs that can improve seating comfort. [Solution] The chair backrest 5 includes a core material 6 and a cushioning material 7 that covers the core material 6. The core material 6 includes a plurality of plate-like members 61, 62, 63 that extend vertically and are arranged along the backrest shape which curves backward in a convex shape when viewed from above. The lower ends of the plate-like members 61, 62, 63 are supported by a support member 8 in a cantilevered manner, and the upper ends are elastic so that they can be displaced outward from the backrest 5. The plurality of plate-like members 61, 62, 63 do not have uniform bending rigidity.

Description

Technical Field

[0001] The present invention relates to a backrest of a chair, and more particularly to a backrest including a core material and a cushion material covering the core material.

Background Art

[0002] Conventionally, there is a chair with a backrest curved so as to surround the upper body of a seated person. As such a backrest of a chair, for example, a backrest formed by arranging a plurality of plate-like members is known (see, for example, Patent Document 1).

[0003] Generally, when a seated person leans against the backrest of a chair, the load is not always evenly applied to the entire backrest, and the load varies depending on the position of the backrest. Also, the load does not always act on the center of the backrest, and it often shifts to the left or right. In the conventional backrest of a chair, depending on the direction in which the seated person leans, it may not be comfortable, and there has been room for improvement in the sitting comfort.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0006] The present invention relates to a chair backrest, comprising a core material and a cushioning material covering the core material, wherein the core material includes a plurality of plate-like members that each extend in the vertical direction and are arranged along the backrest shape which is curved in a rearward convex shape in a plan view, the lower end of each plate-like member is supported by a support member in a cantilevered manner, and the upper end is elastic so as to be displaceable outward from the backrest, and the plurality of plate-like members have non-uniform bending rigidity.

[0007] According to the chair back of the present invention, the bending rigidity of the multiple plate-shaped members forming the core material of the backrest is not uniform, which allows the rebound force of the backrest when a sitter leans against it to vary depending on the position of the backrest, thereby improving seating comfort.

[0008] In the chair back of the present invention, the plurality of plate-like members may be arranged along the rear edge and left and right side edges of the chair seat in a plan view. Furthermore, the bending rigidity of the plate-like members along the rear edge of the seat may be higher than that of the plate-like members along the left and right side edges of the seat.

[0009] In this configuration, when a sitter leans against the backrest portion along the rear edge of the seat, the sitter's back is firmly supported, while when a sitter leans against the backrest portion along the left and right side edges of the seat, the backrest portion deforms with a relatively small rebound force, supporting the sitter's back (or their side or upper arm when leaning sideways).

[0010] Furthermore, among the plurality of plate-like members along the left and right side edges of the seat, the bending rigidity of the plate-like member disposed closer to the rear edge of the seat may be higher than that of the plate-like member disposed closer to the front edge of the seat.

[0011] In this configuration, the rebound force of the backrest when a seated person leans diagonally backward can be made greater than the rebound force of the backrest when a seated person leans to the side, thereby providing firm support for the seated person's back.

[0012] In the chair back of the present invention, the upper parts of at least two adjacent plate-like members may be connected by a bending and deformable connecting member.

[0013] In this configuration, when a seated person leans back, multiple plate-shaped members connected by connecting members deform in conjunction, thus distributing the load on a single plate-shaped member and preventing plastic deformation of the plate-shaped member. [Effects of the Invention]

[0014] The chair backrest of the present invention can improve seating comfort because it can vary the rebound force of the backrest depending on the position of the backrest when the sitter leans against it. [Brief explanation of the drawing]

[0015] [Figure 1] This is a front view of a chair with a backrest according to an embodiment. [Figure 2] (A) is a top view of the chair, and (B) is a rear view. [Figure 3] (A) is a left side view of the chair, and (B) is a left side view showing the backrest in a reclined position. [Figure 4] (A) is a perspective view of the chair from the front, and (B) is a perspective view from the rear. [Figure 5] This is an exploded perspective view of the base and back base. [Figure 6] This is an exploded perspective view of the core material of the backrest, the back frame, and the rear back base. [Figure 7] This is a disassembled perspective view of the back frame. [Figure 8] This is an exploded perspective view of the core material and back frame of the backrest. [Figure 9] This is a longitudinal cross-sectional view at position AA in Figure 2(A). [Figure 10] These are explanatory diagrams of other embodiments of the backrest, where (A) is a left side view and (B) is a rear view. [Modes for carrying out the invention]

[0016] 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, with respect to the embodiment of the chair, these terms of front and back and left and right are based on the seated person. 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 seen from the seated person.

[0017] (1) Outline of the chair First, the outline of the chair will be mainly described based on FIGS. 1 to 6. The backrest 5 of the present embodiment is applied to a swivel chair frequently used for office work or the like. The chair includes a leg support 1 composed of a gas cylinder and a leg device 2 having casters, a base 3 fixed to the upper end of the leg support 1, a seat 4 disposed on the base 3, and a backrest 5 on which a seated person can lean. The backrest 5 is provided in a substantially U-shaped forward opening along the rear edge portion 41 of the seat 4 and the left and right seat side edge portions 42 in plan view. In the present embodiment, the front edge portion of the backrest 5 is disposed on the rear side of the front edge portion 43 of the seat in side view.

[0018] The backrest 5 includes a core material 6 and a cushion material 7 covering the core material 6. The core material 6 includes a plurality of plate-like members 61, 62, 63 that extend in the vertical direction and are arranged along the shape of the backrest 5 that is curved convex backward in plan view. The plate-like members 61, 62, 63 are supported by a back frame 8 (support member) in a cantilever manner at the lower end side and have elasticity so that the upper end side can be displaced toward the outside of the backrest 5.

[0019] In the present embodiment, the core material 6 includes a plurality of rear plate-like members 61 arranged along the rear edge portion 41 of the seat 4, a plurality of side rear plate-like members 62 arranged obliquely forward from both left and right ends of the arrangement of the rear plate-like members 61 toward the left and right outside, and a plurality of side front plate-like members 63 arranged forward along the seat side edge portion 42 from the front end of the arrangement of the side rear plate-like members 62. The side rear plate-like members 62 are disposed near the left and right rear corner portions of the seat 4.

[0020] Multiple plate-like members 61, 62, and 63 are arranged so that their bending rigidity is not uniform. In this embodiment, the bending rigidity of the plate-like members 61, 62, and 63 increases in the order of the rear plate-like member 61, the side rear plate-like member 62, and the side front plate-like member 63. In this way, by having multiple plate-like members 61, 62, and 63 that form the core material 6 of the backrest 5 have non-uniform bending rigidity, the rebound force of the backrest 5 when a sitter leans against it can be appropriately designed depending on the location of the backrest 5, thereby improving seating comfort.

[0021] As shown in Figures 1 to 5, the base 3 is formed in the shape of a box with an upward opening. A back base 12 to which the backrest 5 is attached is connected to the base 3 so as to be able to tilt backward. The back base 12 is composed of a front back base 13 connected to the base 3 and a rear back base 14 to which the backrest 5 is attached. The front back base 13 and the rear back base 14 fit together and are fixed with screws 15.

[0022] The front back base 13 is equipped with a pair of forward-facing arm sections 13a extending forward from the outer position of the base 3. The front ends of the left and right forward-facing arm sections 13a are connected to the base 3 by a horizontally elongated first support shaft 16. Therefore, the backrest 5 tilts around the axis of the first support shaft 16, as shown in Figure 5(B). The chair in this embodiment is a synchronized type chair in which the seat 4 moves backward and tilts in conjunction with the backward tilt of the backrest 5, but a detailed explanation of the mechanism is omitted.

[0023] (2) Construction of the backrest

[0024] The backrest 5 comprises a core material 6 for upright posture and a cushioning material 7 covering the core material 6. The backrest 5 also comprises a back frame 8 (supporting member) that supports the core material 6. As described above, the core material 6 comprises a plurality of plate-like members 61, 62, and 63 arranged along the shape of the backrest 5, which curves backward in a convex shape when viewed from above. The back frame 8 is provided in a roughly U-shape with a forward-facing opening along the rear edge 41 of the seat and the left and right side edges 42 of the seat when viewed from above, and supports the lower ends of the plate-like members 61, 62, and 63 in a cantilevered manner.

[0025] The back frame 8 is positioned slightly higher than the seat 4 and in a nearly horizontal position. The back frame 8 comprises a rear frame 81 extending laterally above the rear edge 41 of the seat, a pair of left and right rear back frame parts 82 extending diagonally forward from the left and right ends of the rear frame 81 outwards, and a pair of left and right front back frame parts 83 extending forward from the front ends of the rear back frame parts 82. The frames 81, 82, and 83 are provided in a cylindrical shape with a nearly square cross-section.

[0026] As shown in Figures 6 and 7, the back frame 8 is formed into a roughly U-shaped cylinder by combining front and rear metal plates 84 and 85, which are bent into a roughly U-shape, with upper and lower metal plates 86 and 87, which are cut out in a roughly U-shape. The metal plates 84, 85, 86, and 87 are connected, for example, by welding. The metal plates 84, 85, 86, and 87 have multiple openings to reduce weight.

[0027] The front metal plate 84 forms the inner circumferential sides 81a, 82a, and 83a. The inner circumferential edge of the upper metal plate 86, which forms the upper surfaces 81c, 82c, and 83c, is connected to the upper edge of the front metal plate 84. The inner circumferential edge of the lower metal plate 87, which forms the lower surfaces 81d, 82d, and 83d, is connected to the lower edge of the front metal plate 84. The outer circumferential edge of the upper metal plate 86 is connected to the upper edge of the rear metal plate 85. The outer circumferential edge of the lower metal plate 87 is connected to the lower edge of the rear metal plate 85.

[0028] The upper parts of a pair of left and right backrest connecting members 17, which are erected on the rear back base 14, are fixed to the rearward-facing outer peripheral side surface 81b of the rear frame 81, for example, by bolt fastening. As a result, the back frame 8 is connected to the rear back base 14 and supported by the base 3 via the back base 12.

[0029] In this embodiment, the rear frame 81 is provided in a straight line that is shorter than the left-right width of the seat 4, and the left and right ends of the rear frame 81 are located to the left and right inward of the left and right ends of the rear edge 41 of the seat. The back side rear frame 82 extends in a straight line diagonally forward from the left and right ends of the rear frame 81 toward a position diagonally upward to the left and right outward of the middle part of the seat edge 42. The back side front frame 83 extends in a straight line forward from the front end of the back side rear frame 82 toward a position diagonally upward to the left and right outward of the part of the seat edge 42 closer to the front end.

[0030] Furthermore, each frame 81, 82, and 83 constituting the back frame 8 may be curved in at least one of its views, both in plan and from the side, and may be positioned in an inclined orientation when viewed from the side.

[0031] As shown in Figures 1 to 6, the plate-like members 61, 62, and 63 constituting the core material 6 are made of metal and are each arranged in an upright position, aligned along the rear edge 41 of the seat and the left and right side edges 42 of the seat. The lower ends of the plate-like members 61, 62, and 63 are fixed to the inner circumferential surfaces 81a, 82a, and 83a of the back frame 8. The lower ends of multiple rear plate-like members 61 are fixed to the forward-facing inner circumferential surface 81a of the rear frame 81. The lower ends of multiple side rear plate-like members 62 are fixed to the diagonally forward-facing inner circumferential surface 82a of the rear side frame 82. The lower ends of multiple side front plate-like members 63 are fixed to the left and right inward-facing inner circumferential surfaces 83a of the front front frame 83.

[0032] In this embodiment, eight rear plate-like members 61 are supported on the forward-facing inner circumferential surface 81a, arranged at equal intervals. Additionally, five side rear plate-like members 62 are supported on each of the left and right diagonally forward-facing inner circumferential surface 82a, arranged at equal intervals. Furthermore, four side front plate-like members 63 are supported on each of the left and right inward-facing inner circumferential surface 83a, arranged at equal intervals. Gaps are provided between adjacent plate-like members 61, 62, and 63. In other words, the plate-like members 61, 62, and 63 are supported by the back frame 8 with gaps between them.

[0033] The plate-like members 61, 62, and 63 are supported by the back frame 8 in a cantilevered manner at their lower ends, and are elastic enough to be displaceable at their upper ends toward the outside of the backrest. The bending rigidity of the plate-like members 61, 62, and 63 is not uniform but differs from one another. For example, by making the material, thickness, width, length, and shape of the plate-like members 61, 62, and 63 different from one another, the bending rigidity of the plate-like members 61, 62, and 63 can be made to differ from one another.

[0034] In this embodiment, the bending rigidity of the plate-like members 61, 62, and 63 is highest in the rear plate-like member 61, followed by the side rear plate-like member 62, and then the side front plate-like member 63. This configuration can be achieved, for example, by having plate-like members 61, 62, and 63 with substantially the same shape, and their thickness increasing in the order of the rear plate-like member 61, the side rear plate-like member 62, and then the side front plate-like member 63.

[0035] The plate-like members 61, 62, and 63 are positioned in an inclined position with their upper parts bent outward, so that their upper ends are located outside the base end (the joint with the back frame 8) in a plan view. As a result, when a load is applied from above to the upper ends of the plate-like members 61, 62, and 63, the plate-like members 61, 62, and 63 curve outward. Furthermore, when an inward force is applied to the outer circumference of the backrest 5, the plate-like members 61, 62, and 63 elastically deform to curve inward.

[0036] As shown in Figures 1 to 4 and Figure 9, the core material 6 is covered with cushioning material 7. The cushioning material 7 comprises an inner cushioning material 71 that covers the inner circumference of the core material 6 and an outer cushioning material 72 that covers the outer circumference of the core material 6. The upper end of the inner cushioning material 71 and the upper end of the outer cushioning material 72 are connected, and the cushioning material 7 covers the upper ends of the plate-shaped members 61, 62, and 63.

[0037] The lower part of the inner cushioning material 71 also covers the inner side surfaces 81a, 82a, and 83a of the back frame 8. The lower end of the outer cushioning material 72 is located above the rear upper surface 81c, the rear upper surface 82c, and the front upper surface 83c of the back frame 8. The surface of the cushioning material 7 is covered with a surface material 9 (see Figure 9), such as upholstery. Note that the surface material 9 is not shown in Figures 1 to 4.

[0038] As shown in Figures 1 to 4 and Figure 9, a back frame cover 10 that covers the back frame 8 and a back base cover 11 that covers the rear back base 14 are provided. The back base cover 11 is box-shaped and is provided to cover the rear back base 14 from the rear.

[0039] The back frame cover 10 is provided in a roughly C-shape in cross-section so as to cover the outer peripheral sides 81b, 82b, 83b, top surfaces 81c, 82c, 83c, and bottom surfaces 81d, 82d, 83d of the back frame 8. The back frame cover 10 is also provided so as to cover the front end portions (parts not covered by the inner cushioning material 71) of the left and right inward inner peripheral sides 83a of the back frame 8, and the forward-facing openings of the left and right front back frame parts 83. Note that the back frame cover 10 and the back base cover 11 may be divided into multiple parts.

[0040] In this embodiment, the multiple plate-like members 61, 62, and 63, which are arranged along the shape of the backrest 5 which curves backward in a convex shape when viewed from above, are supported at their lower ends in a cantilevered manner by the back frame 8, and their upper ends are elastic so that they can be displaced outward from the backrest 5. Furthermore, since the bending rigidity of the multiple plate-like members 61, 62, and 63 is not uniform, the rebound force of the backrest 5 when a sitter leans against it can be varied depending on the position of the backrest 5, thereby improving seating comfort.

[0041] Furthermore, in the backrest 5, the multiple plate-like members 61, 62, and 63 are arranged along the rear edge 41 and the left and right side edges 42 of the seat 4 of the chair in a plan view. The bending rigidity of the rear plate-like member 61 along the rear edge 41 is higher than that of the plate-like members 62 and 63 along the side edges 42. As a result, when a sitter leans against the part of the backrest 5 along the rear edge 41, the sitter's back is firmly supported, while when a sitter leans against the part of the backrest 5 along the side edges 42, the backrest deforms with a relatively small rebound force to support the sitter's back (or their side or upper arm when leaning sideways).

[0042] Furthermore, among the multiple plate-like members 62, 63 along the side edge 42 of the seat, the bending rigidity of the side rear plate-like member 62, which is located closer to the rear edge 41 of the seat, is set to be higher than that of the side front plate-like member 63, which is located closer to the front edge 43 of the seat 4. As a result, the rebound force of the backrest 5 when a sitter sitting on the seat 4 facing forward leans diagonally backward against the backrest 5 can be made greater than the rebound force of the backrest 5 when the sitter leans to the left or right sideways against the backrest 5, thereby firmly supporting the sitter's back.

[0043] Furthermore, the plate-shaped members 61, 62, and 63 are arranged with gaps between them, and are covered with cushioning material 7 to fill the gaps between adjacent plate-shaped members 61, 62, and 63. As a result, when a sitter leans back against the backrest 5, the plate-shaped members 61, 62, and 63 and the cushioning material 7 elastically deform to envelop the sitter's upper body (back, upper arms, and sides), improving seating comfort.

[0044] (3) Other embodiments As shown in Figure 10, in this embodiment, the upper parts of adjacent plate-shaped members 61 and 61, 61 and 62, 62 and 62, 62 and 63, and 63 and 63 are connected by a bending and deformable connecting member 64. The connecting member 64 is provided, for example, as a single non-stretchable or stretchable string or tape, and comprises a fixing portion 64a fixed to each of the plate-shaped members 61, 62, and 63 so as not to move relative to each other, and a connecting portion 64b connecting adjacent fixing portions 64a.

[0045] The fixing portion 64a is fixed to the outward-facing upper surface of the plate-shaped members 61, 62, and 63 with fasteners 65, such as screws. The connecting portion 64b is provided to be in a relaxed state when no external force is applied to the backrest 5.

[0046] In this embodiment, for example, if the upper part of one of two adjacent rear plate-shaped members 61, 61 is displaced outward, the connecting portion 64b that connects the rear plate-shaped members 61, 61 becomes taut. If the upper part of one rear plate-shaped member 61 is displaced further outward, the connecting portion 64b fixed to the other rear plate-shaped member 61 is pulled by the connecting portion 64b, causing the upper part of the other rear plate-shaped member 61 to be displaced outward.

[0047] In other words, adjacent rear plate-shaped members 61, 61 connected by the connecting member 64 deform in conjunction. Similarly, with respect to adjacent plate-shaped members 61 and 62, 62 and 62, 62 and 63, and 63 and 63, the other plate-shaped member deforms in conjunction with the deformation of one plate-shaped member. In this way, when a seated person leans against the backrest 5, the multiple plate-shaped members 61, 62, 63 connected by the connecting member 64 deform in conjunction, thus distributing the load on a single plate-shaped member and preventing plastic deformation of the plate-shaped member.

[0048] In this embodiment, all plate-like members 61, 62, and 63 of the backrest 5 are connected by connecting members 64, but it is also acceptable for only some of the plate-like members 61, 62, and 63 to be connected by connecting members 64. Furthermore, although the plate-like members 61, 62, and 63 are connected by a single connecting member 64, the connecting member 64 may be divided into multiple pieces in the longitudinal direction. Also, adjacent fixing parts 64a may be at different height positions. Also, adjacent connecting parts 64b may be at different lengths. Furthermore, the material of the connecting member 64 may be either non-stretchable or stretchable.

[0049] Although embodiments have been described above, the present invention is not limited to the embodiments described above and can be embodied in various forms. The configuration of each part is not limited to the illustrated embodiments and can be modified in various ways without departing from the spirit of the present invention. For example, the configurations described in the above embodiments and modifications (see notes, etc.) may be combined, and the configurations can be added, omitted, replaced, or otherwise modified.

[0050] For example, although the backrest 5 is provided with three types of plate-like members 61, 62, and 63 having different bending rigidities, there may be two types of plate-like members with different bending rigidities, or four or more types. Furthermore, the plate-like members 61, 62, and 63 are not limited to being made of metal, but may be made of other materials such as resin, wood, FRP, or carbon.

[0051] The cushioning material 7 only needs to be provided so as to cover at least the inward-facing side surface of the core material 6. The material of the cushioning material 7 is not particularly limited as long as it is a material commonly used as cushioning material for chairs. Furthermore, the cushioning material 7 may have a laminated structure of two or more layers.

[0052] Furthermore, the spacing between the plate-like members 61, 62, and 63 can be changed as appropriate. In the above embodiment, the multiple rear plate-like members 61 are arranged at equal intervals, but the spacing between the rear plate-like members 61 does not have to be uniform. Similarly, the spacing between the side rear plate-like members 62 and the side front plate-like members 63 does not have to be uniform. Also, the spacing between the rear plate-like members 61, the spacing between the side rear plate-like members 62, and the spacing between the side front plate-like members 63 may be the same or may be different from each other.

[0053] Furthermore, the chair back of the present invention can be applied to chairs that do not have a rocking function or a swivel function, and can also be applied to floor chairs that do not have support legs. [Explanation of symbols]

[0054] 4 seats 5 Backrest 6 Core material 7. Cushioning material 8. Back frame (support member) 41 Rear edge of the seat 42 Seat side edge 43 Seat front edge 61 Rear plate-shaped member 62 Side rear plate-like member 63 Side front plate-like member 64 Connecting Members 71 Inner perimeter cushioning material 72 Perimeter cushioning material

Claims

1. It is the backrest of a chair, It includes a core material and a cushioning material that covers the core material, The core material includes a plurality of plate-like members that extend vertically and are arranged along a backrest shape that curves backward in a convex shape when viewed from above. The plate-like member is supported by a support member in a cantilevered manner at its lower end, and has elasticity so that its upper end can be displaced outward from the backrest. The aforementioned plurality of plate-like members have non-uniform bending rigidity. The backrest of a chair.

2. The aforementioned plurality of plate-like members are arranged along the rear edge and left and right side edges of the chair seat in a plan view. The bending rigidity of the plate-shaped member along the rear edge of the seat is higher than that of the plate-shaped member along the left and right side edges of the seat. The backrest of the chair according to claim 1.

3. Of the multiple plate-like members along the left and right side edges of the seat, the bending rigidity of the plate-like member disposed closer to the rear edge of the seat is higher than that of the plate-like member disposed closer to the front edge of the seat. The chair backrest according to claim 2.

4. At least two adjacent plate-like members are connected at their upper parts by a flexible connecting member. A chair backrest according to any one of claims 1 to 3.

Images