Backrest

Abstract

To optimize the shape of an upholstery material in a backrest having the upholstery material forming a load support surface.SOLUTION: The backrest 7 includes a pair of left and right upright rods 40 extending in the vertical direction, an upper connection rod 45 that connects upper end portions of the pair of upright rods 40 to each other, and a tension member that is stretched between the pair of upright rods 40 and the upper connection rod 45 to form a load support surface. The upper connecting rod 45 has a backrest portion 47 extending along the left-right direction in a plan view. The upper connection rod part 45 is formed with an upper engagement recessed part 61 which is provided from a pair of front end parts to the backrest part 47, extends along the extension direction of the upper connection rod part 45, opens upward, and with which the upper edge part of the tension material is engaged. Each of the pair of upright rods 40 is provided with a side engagement recess 62 that extends along the extending direction of each of the pair of upright rods 40, opens forward, and is engaged with the tensile material. The upper engagement recess 61 and the side engagement recess 62 communicate with each other.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] In a known configuration of a chair backrest that includes a back frame having left and right side frame portions and an upper frame portion, and an upholstery material that is stretched over the back frame to form a load-bearing surface, the back frame is provided with a recess that engages with the upholstery material (see, for example, Patent Document 1).In the backrest described in Patent Document 1, the recess is formed continuously from the outer surfaces of the side frame portions to the upper surface of the upper frame portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5620158 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which an upholstery material is stretched over a back frame, it is desirable to optimize the shape of the upholstery material in order to prevent the upholstery material from being soiled or damaged by external contact.

[0005] Therefore, the present invention is directed to optimizing the shape of an upholstery material in a backrest having an upholstery material that forms a load-bearing surface. [Means for solving the problem]

[0006] The backrest according to a first aspect of the present invention is a backrest that is supported by a support structure and has a load support surface above the seat that supports the weight of a seated person, and includes a pair of left and right standing rods extending in the vertical direction, a connecting rod that connects the upper ends of the pair of standing rods, and a tensioning material that is stretched over the pair of standing rods and the connecting rod to form the load support surface, and the connecting rod has a pair of front ends that connect to the upper ends of the pair of standing rods, and a backrest that extends in the left and right direction in a plan view. The connecting rod portion has a first engagement recess that extends from the pair of front ends to the backrest portion, extends along the extension direction of the connecting rod portion, opens upward, and engages with the upper edge of the upholstery material, and each of the pair of standing rod portions has a second engagement recess that extends along the extension direction of each of the pair of standing rod portions, opens forward, and engages with the upholstery material, and the first engagement recess and the second engagement recess are connected to each other.

[0007] According to the first aspect, the upholstery material can be stretched over the connecting rod by engaging the upper edge of the upholstery material with the first engagement recess. The upholstery material can also be stretched over the standing rod by engaging the second engagement recess. Here, because the first engagement recess is open upward, the upholstery material can be prevented from being positioned behind the connecting rod. Furthermore, because the second engagement recess is open forward, the upholstery material can be prevented from being positioned on the left-right outside of the standing rod. Furthermore, because the first and second engagement recesses are connected to each other, the upholstery material can be continuously engaged from the first engagement recess to the second engagement recess, preventing the upholstery material from spilling out from between the first and second engagement recesses. As a result, the upholstery material can be prevented from being positioned in the space around the chair relative to the rods of the backrest and coming into contact with the outside, optimizing the shape of the upholstery material.

[0008] A backrest according to a second aspect of the present invention is the backrest according to the first aspect, wherein the first engagement recess has a backrest engagement recess provided in the backrest portion, and the backrest engagement recess may be located forward of the upper rear end of the backrest portion.

[0009] According to the second aspect, the upholstery material is pulled out from the backrest engagement recess, which is located forward of the upper rear end of the backrest, to the front of the backrest. This prevents the upholstery material from being positioned further rearward than the upper rear end of the backrest, and prevents the upholstery material from coming into contact with the outside.

[0010] A backrest according to a third aspect of the present invention is the backrest according to the first or second aspect, wherein the backrest portion may have an upper surface facing forward and upward.

[0011] According to the third aspect, when a user grips the backrest, the user can easily place his or her fingers on the upper rear end of the backrest, thereby preventing the user from touching the upholstery material that is positioned further forward than the upper rear end of the backrest.

[0012] A backrest according to a fourth aspect of the present invention may be a backrest according to any one of the first to third aspects, further comprising an auxiliary holding portion that is located below the first engagement recess and rearward of the second engagement recess and that holds the lower edge of the upholstery material.

[0013] According to the fourth aspect, the upper edge of the upholstery material is stretched over the connecting rod, the left and right side edges of the upholstery material are stretched over the pair of standing rods, and the lower edge of the upholstery material is held by the auxiliary holding part, so no loose ends are formed in the upholstery material, and the shape retention of the upholstery material can be ensured.

[0014] A backrest according to a fifth aspect of the present invention is a backrest according to any one of the first to fourth aspects, further comprising a lower connecting rod portion connecting the pair of standing rod portions, the lower connecting rod portion being connected to a point lower than the connection portion of the standing rod portion with the connecting rod portion, the lower connecting rod portion having a third engagement recess formed therein extending along the extension direction of the lower connecting rod portion, and the auxiliary holding portion may be the third engagement recess.

[0015] According to the fifth aspect, the upholstery material can be tensioned on the lower connecting rod by engaging the upholstery material with the third engagement recess. Furthermore, since the lower edge of the upholstery material is housed in the third engagement recess, the appearance of the upholstery material can be improved. [Effects of the Invention]

[0016] According to the present invention, in a backrest having an upholstery material that forms a load-bearing surface, the shape of the upholstery material can be optimized. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view of a chair 1 according to an embodiment, seen from above. [Figure 2] 1 is a perspective view of a chair 1 according to an embodiment, seen from below. [Figure 3] FIG. 7 is a cross-sectional view taken along line III-III in FIG. 6. [Figure 4] FIG. 8 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 2 is a perspective view of a load support member 9 according to the embodiment. [Figure 6] 1 is a front view of a chair 1 according to an embodiment. [Figure 7] 1 is a side view of a chair 1 according to an embodiment. [Figure 8] 1 is a plan view of a chair 1 according to an embodiment. [Figure 9] FIG. 6 is a cross-sectional view taken along line IX-IX in FIG. 5. [Figure 10] FIG. 6 is a cross-sectional view taken along line XX in FIG. 5. [Figure 11] FIG. 6 is a cross-sectional view taken along line XI-XI in FIG. 5. [Figure 12] FIG. 6 is a cross-sectional view taken along line XII-XII in FIG. 5. [Figure 13] 10 is a rear view showing the middle portion in the left-right direction of the upper connecting rod portion 45 of the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions will be designated by the same reference numerals. Duplicate descriptions of these components may be omitted. In the following description, directions such as front, back, up, down, left, and right will be the same as the directions of a person (seater) sitting normally in a chair. That is, the direction in which a seated person faces forward will be referred to as "forward," and the opposite direction will be referred to as "rear." Furthermore, in each drawing, the arrow UP indicates upward, the arrow FR indicates forward, and the arrow LH indicates leftward. In this embodiment, "integrally formed" means that at least a portion of all parts of a target are formed from a single member. That is, when multiple parts are integrally formed, a continuous member is provided for all of the target parts. However, a member other than the single member may be provided for some of the target parts.

[0019] FIG. 1 is a perspective view of a chair 1 according to an embodiment, seen from above. 1, a chair 1 of the embodiment includes a support structure 3, a seat 5, and a backrest 7. The chair 1 has a seating space S above the seat 5.

[0020] Fig. 2 is a perspective view of the chair 1 according to the embodiment, seen from below. Note that in Fig. 2 and subsequent figures, an upholstery material 70, which will be described later, may be omitted from the illustration. As shown in FIGS. 1 and 2, the support structure 3 includes legs 10 and a support base 15 .

[0021] The leg body 10 includes a multi-leg 11 and a leg post 12. Each leg of the multi-leg 11 is fitted with a caster that allows it to run on the floor. A footrest may be attached to the multi-leg 11. The leg post 12 extends upward from the center of the multi-leg 11. A gas spring, which is the lifting mechanism for the chair 1, is built into the leg post 12. The gas spring is configured such that an inner tube is supported so as to be able to move up and down and rotate relative to an outer tube (not shown) provided within the leg post 12. A support base 15 is connected to the upper end of the leg post 12 (inner tube). The support base 15 supports the seat 5 from below. A lever for operating the gas spring is attached to the support base 15.

[0022] The seat 5 supports the buttocks and thighs of the seated person. The seat 5 is indirectly supported by the support base 15 of the support structure 3 via the backrest 7. The seat 5 comprises a seat plate 20 that receives the seating load, and a cushion 23 arranged above the seat plate 20. The seat plate 20 is formed in a circular or rectangular shape in plan view so that its shape in plan view approximately matches the shape of the seat 5 in plan view. The cushion 23 is arranged along the upper surface of the seat plate 20 and is supported by the seat plate 20. The cushion 23 is arranged so as to overlap the entire seat plate 20 when viewed from above.

[0023] Fig. 3 is a cross-sectional view taken along line III-III in Fig. 6. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 7. As shown in Figures 2 to 4, the seat 5 further includes a seat plate support member 26. The seat plate support member 26 supports the seat plate 20 from below. The seat plate support member 26 is connected to the seat plate 20 so that it can be displaced in the front-to-rear direction. The seat plate support member 26 connects the seat plate 20 so that it cannot be displaced in the up-down direction or the left-to-right direction.

[0024] As shown in Figures 1 and 2, the backrest 7 is supported by the support structure 3. The backrest 7 has a load support surface 8 that supports the weight of a seated person and is located above the seat 5. The backrest 7 cannot tilt relative to the seat 5. The backrest 7 is formed substantially symmetrically. The backrest 7 includes a load support member 9 and an upholstery material 70.

[0025] FIG. 5 is a perspective view of the load support member 9 according to the embodiment. As shown in FIG. 5, the load support member 9 includes a seat receiving portion 30, a pair of left and right horizontal rod portions 35, a pair of left and right standing rod portions 40, an upper connecting rod portion 45, and a lower connecting rod portion 50.

[0026] As shown in Figures 3 to 5, the seat support portion 30 is connected to the support structure 3 so that it cannot move up and down or left and right. The seat support portion 30 is connected to the seat 5 so that it cannot move up and down. The seat support portion 30 has a lower surface 30l that is supported by the support structure 3 and an upper surface 30u that supports the seat 5 from below. The seat support portion 30 is connected to the seat plate support member 26 of the seat 5 from below, and is interposed between the seat 5 and the support base 15, thereby indirectly connecting the seat 5 and the support base 15 to each other. The seat support portion 30 has an upper wall portion 31 that extends horizontally, and a peripheral wall portion 32 that extends downward from the upper wall portion 31. The upper wall portion 31 and the peripheral wall portion 32 are formed integrally.

[0027] The upper wall portion 31 is a portion of the seat support portion 30 that has a lower surface 30l and an upper surface 30u. The upper wall portion 31 is a plate-like shape that has a rectangular shape in a plan view, with one pair of sides extending in the front-to-rear direction and the other pair of sides extending in the left-to-right direction. The support base 15 is connected to the upper wall portion 31 from below, and the seat plate support member 26 is connected to the upper wall portion 31 from above. The support base 15 and the seat plate support member 26 are fastened to the upper wall portion 31 by a common fastening member.

[0028] The peripheral wall portion 32 extends downward from the outer peripheral edge of the upper wall portion 31. The peripheral wall portion 32 is connected to the outer peripheral edge of the upper wall portion 31 around the entire periphery. As a result, the peripheral wall portion 32 has a pair of left and right side wall portions 32a extending along the front-rear direction, and a front wall portion and a rear wall portion extending along the left-right direction. The seat receiving portion 30 is formed in a box shape that is open downward. The support base 15 is arranged inside the seat receiving portion 30.

[0029] FIG. 6 is a front view of the chair 1 according to the embodiment. As shown in Figures 5 and 6, the pair of horizontal rod portions 35 correspond one-to-one to the pair of side wall portions 32a. The horizontal rod portions 35 are connected to the side wall portions 32a. The horizontal rod portions 35 are formed integrally with the seat support portion 30. In this embodiment, the entire horizontal rod portion 35 is formed integrally with the entire seat support portion 30. The horizontal rod portions 35 are connected to the middle portion of each side wall portion 32a in the front-to-rear direction. In other words, the horizontal rod portions 35 are connected to positions spaced apart in the front-to-rear direction from the front end and rear end of each side wall portion 32a. The horizontal rod portions 35 extend outward in the left-to-right direction from each side wall portion 32a. The horizontal rod portions 35 extend in the left-to-right direction in the space below the seat 5. It is desirable that the horizontal rod portion 35 does not contact the seat 5, but for example, in a configuration in which the seat plate 20 does not displace in the front-to-rear direction relative to the seat plate support member 26, the horizontal rod portion 35 may contact the seat 5. The outer end of the horizontal rod portion 35 is located outside the seat 5 in a plan view.

[0030] The cross section of the horizontal rod portion 35 perpendicular to the left-right direction is rectangular with the longitudinal direction extending in the front-to-rear direction. The upper surface 35u of the horizontal rod portion 35 is connected to the upper surface 30u of the seat support portion 30 via a stepped surface 32b provided on the side wall portion 32a and facing outward in the left-right direction. As a result, the upper surface 35u of the horizontal rod portion 35 extends outward in the left-right direction from a position lower than the upper surface 30u of the seat support portion 30. Note that the normal direction of the stepped surface 32b does not have to be parallel to the left-right direction, as long as the normal vector of the stepped surface includes a component pointing outward in the left-right direction.

[0031] FIG. 7 is a side view of the chair 1 according to the embodiment. As shown in Figures 5 and 7, the pair of standing rods 40 correspond one-to-one to the pair of horizontal rods 35. The standing rods 40 are connected to the horizontal rods 35. The standing rods 40 are formed integrally with the horizontal rods 35. In this embodiment, the standing rods 40 are formed integrally with the entire horizontal rods 35. The standing rods 40 have a length in the vertical direction. The standing rods 40 have lower ends connected to the outer left-right ends of each horizontal rod 35. The standing rods 40 extend upward from their lower ends in the space outside the left-right direction of the seat 5 in a front view. The load support member 9 is smoothly bent at the connection between the horizontal rods 35 and the standing rods 40 so that the outer surface is continuous. The standing rods 40 cross the seat 5 in a side view from the left-right direction. The upper end of the standing rod portion 40 is within the range in which the seat receiving portion 30 is formed in the front-rear direction.

[0032] The cross section of the standing rod portion 40 perpendicular to the up-down direction is rectangular with the longitudinal direction extending in the front-to-rear direction. The rectangular cross section of the standing rod portion 40 improves rigidity against loads from vertically above. The standing rod portion 40 has a front surface 40f facing forward and an inner surface 40i facing the seating space S. For example, the front surface 40f is defined by an area of ​​the outer surface of the standing rod portion 40 that is visible from the front. The front surface 40f extends over the entire length of the standing rod portion 40. The inner surface 40i extends over the entire length of the standing rod portion 40. The inner surface 40i is continuous with the upper surface 35u of the horizontal rod portion 35.

[0033] FIG. 8 is a plan view of the chair 1 according to the embodiment. As shown in Figures 5 and 8, the upper connecting rod 45 connects the upper ends of the pair of upright rods 40. The upper connecting rod 45 is formed integrally with the upright rod 40. In a plan view, the upper connecting rod 45 is formed in a U-shape that opens forward and is curved so as to convex rearward. The upper connecting rod 45 is arranged to surround the seating space S from both the left and right sides and the rear. In a side view seen from the left and right direction, the upper connecting rod 45 extends upward and rearward from the front end of the upper connecting rod 45 (see Figure 7). The load support member 9 is smoothly bent so that the outer surface is continuous at the connection between the upright rod 40 and the upper connecting rod 45. The upper connecting rod 45 includes a pair of left and right armrests 46, a backrest 47, and an extension 48.

[0034] As shown in FIG. 5 , the pair of armrests 46 correspond one-to-one to the pair of upright rods 40. The armrests 46 have a length in the front-to-rear direction. The armrests 46 have front ends connected to the upper ends of the upright rods 40. The front ends of the pair of armrests 46 are the front ends of both the left and right sides of the upper connecting rods 45. The armrests 46 extend rearward from their front ends in a plan view. The cross section of the armrests 46 perpendicular to the front-to-rear direction is a rectangle with one pair of sides extending in the up-down direction and the other pair of sides extending in the left-to-right direction. The upper corners 46a, which are outermost in the left-to-right direction, of the armrests 46 are located at the outermost left-to-right position of the armrests 46 in any position in the front-to-rear direction.

[0035] The backrest 47 is connected to the pair of armrests 46. The backrest 47 is formed integrally with the pair of armrests 46. The backrest 47 extends between the rear ends of the pair of armrests 46. The backrest 47 extends outward in the left-right direction from a left-right intermediate portion of the upper connecting rod 45 and is connected to the rear ends of the pair of armrests 46. The backrest 47 only needs to have a region that includes the left-right intermediate portion of the upper connecting rod 45 and extends along the left-right direction, and the boundary between the armrests 46 and the backrest 47 does not need to be uniquely identified. However, for example, if the upper connecting rod has a clearly bent portion in a planar view, the bent portion may be defined as the boundary between the armrests and the backrest.

[0036] The cross section of the backrest 47 perpendicular to the left-right direction has a rectangular shape with one pair of sides extending vertically and the other pair of sides extending upward and rearward. The upper and rear corner 47a of the backrest 47 is located at the rearmost position of the backrest 47 regardless of the position of the backrest 47 in the front-to-rear direction. The upper and rear corner 47a in the middle of the backrest 47 in the left-to-right direction is the upper rear end of the upper connecting rod 45. The upper and rear corner 47a of the backrest 47 is continuous with the upper and outer corner 46a of the armrest 46 in the left-to-right direction. In other words, the upper and outer corner 45a of the upper connecting rod 45 in the horizontal direction is the edge located at the horizontally outermost position of the upper connecting rod 45. In this embodiment, the horizontally outer and upper corner 45a of the upper connecting rod portion 45 is located at the outermost position of the seat 5 and the load support member 9 in the horizontal direction.

[0037] The extension portion 48 extends downward from a middle portion in the left-right direction of the backrest portion 47. The entire extension portion 48 is formed integrally with the backrest portion 47. The extension portion 48 extends in the left-right direction along the backrest portion 47.

[0038] The upper connecting rod portion 45 has an upper surface 45u facing upward and an inner surface 45i facing the seating space S. For example, the upper surface 45u is defined by a region of the outer surface of the upper connecting rod portion 45 that is visible from above. The upper surface 45u is provided over the entire length of the upper connecting rod portion 45. That is, the upper surface 45u is provided continuously from the front ends of the pair of armrests 46 to the backrest portion 47. The upper surface 45u is continuous with the front surface 40f of the upright rod portion 40. In this embodiment, the upper surface 45u is a flat surface that is continuous over the entire length except for the rounded portions on both side edges. The upper surface 45u faces forward and upward. That is, the upper surface 45u faces upward and forward when viewed from the left and right (see FIGS. 6 and 7). Note that the upper surface 45u may also face upward when viewed from the left and right. The portions of the upper surface 45u formed on the armrests 46 are armrest surfaces on which the seated occupant rests their arms (including elbows). The armrest surface of this embodiment can support the arm of the seated occupant from the forearm to the elbow. However, it is sufficient that the armrest surface can support at least the forearm or elbow of the seated occupant. The armrest surface may face upward and inward in the left-right direction when viewed from the front-to-back direction, or upward and outward in the left-to-right direction.

[0039] The inner surface 45i is a concave curved surface that extends in a U-shape in plan view, corresponding to the shape of the upper connecting rod 45 in plan view. The inner surface 45i is provided over the entire length of the upper connecting rod 45. That is, the inner surface 45i is provided continuously from the front ends of the pair of armrests 46 to the backrest 47. The inner surface 45i is continuous with the inner surface 40i of the standing rod 40. Furthermore, the inner surface 45i is provided continuously from the backrest 47 to the extension 48. The portions of the inner surface 45i formed on the armrests 46 face inward in the left-right direction when viewed from above (see FIG. 8). The portions of the inner surface 45i formed on the backrest 47 and the extension 48 face forward when viewed from above (see FIG. 8). The region of the inner surface 45i that is located in the range in which the extension portion 48 is formed in the left-right direction extends downward and forward (see FIG. 9).

[0040] The lower connecting rod 50 connects a pair of standing rods 40 together. The lower connecting rod 50 is located below the upper connecting rod 45. The lower connecting rod 50 is connected to a point on the standing rod 40 below the connection point with the upper connecting rod 45. In other words, the lower connecting rod 50 is connected to the vertical middle of the standing rod 40. The lower connecting rod 50 is formed integrally with the standing rod 40. The lower connecting rod 50 is located above the seat 5 and has a vertical gap with respect to the seat 5 in front view (see FIG. 6). The lower connecting rod 50 is formed in a U-shape that opens forward in plan view and is curved so as to convex backward. The lower connecting rod 50 is located to surround the seating space S from both the left and right sides and the rear. The lower connecting rod portion 50 extends rearward from its front end in a side view from the left-right direction. The left-right middle portion of the lower connecting rod portion 50 is located forward of the left-right middle portion of the upper connecting rod portion 45.

[0041] In this embodiment, substantially the entire load support member 9 is formed from a single member, so that the seat receiving portion 30, the pair of horizontal rod portions 35, the pair of upright rod portions 40, and the upper connecting rod portion 45 are integrally formed.

[0042] As shown in FIGS. 5 and 6 , the lower connecting rod portion 50 has a lower surface 50l facing downward and an inner surface 50i facing the seating space S. For example, the lower surface 50l is defined by a region of the outer surface of the lower connecting rod portion 50 that is visible from below. The lower surface 50l is provided over the entire length of the lower connecting rod portion 50. The inner surface 50i is a concave curved surface that extends in a U-shape in plan view, corresponding to the shape of the lower connecting rod portion 50 in plan view. The inner surface 50i is provided over the entire length of the lower connecting rod portion 50. The inner surface 50i is continuous with the inner surface 40i of the upright rod portion 40.

[0043] Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 5. Fig. 10 is a cross-sectional view taken along line XX in Fig. 5. Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 5. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 5. 5 and 9 to 12, the load support member 9 is formed with an engagement recess 60 into which the upholstery material 70 engages. The engagement recess 60 comprises an upper engagement recess 61 formed in the upper connecting rod portion 45, a pair of left and right side engagement recesses 62 formed in each upright rod portion 40, and a lower engagement recess 63 formed in the lower connecting rod portion 50. The engagement recess 60 extends continuously in an annular shape.

[0044] As shown in Figures 5, 9, and 10, the upper engagement recess 61 is formed in the upper connecting rod portion 45. The upper engagement recess 61 opens to the upper surface 45u of the upper connecting rod portion 45. The upper engagement recess 61 opens to the edge of the upper surface 45u on the seating space S side. The upper engagement recess 61 extends along the extension direction of the upper connecting rod portion 45. The upper engagement recess 61 is provided continuously over the entire length of the upper connecting rod portion 45. The upper engagement recess 61 includes a pair of left and right armrest engagement recesses 61a located in the armrest portion 46 and a backrest engagement recess 61b located in the backrest portion 47. The armrest engagement recess 61a and the backrest engagement recess 61b are directly connected to each other.

[0045] As shown in Figures 5 and 11, the side engagement recesses 62 are formed in each standing rod portion 40. The side engagement recesses 62 open to the front surface 40f of the standing rod portion 40. The side engagement recesses 62 extend in the extension direction of the standing rod portion 40. The side engagement recesses 62 extend along the edge of the front surface 40f on the seating space S side. The upper end of the side engagement recesses 62 is connected to the end of the upper engagement recess 61. As a result, the side engagement recesses 62 are directly connected to the upper engagement recess 61. The lower end of the side engagement recesses 62 opens continuously from the front to the downward direction.

[0046] As shown in Figures 5 and 12, the lower engagement recess 63 is formed in the lower connecting rod part 50. The lower engagement recess 63 opens to the lower surface 50l of the lower connecting rod part 50. The lower engagement recess 63 extends in the extension direction of the lower connecting rod part 50. The lower engagement recess 63 extends along the edge of the lower surface 50l on the seating space S side. The lower engagement recess 63 is provided continuously over the entire length of the lower connecting rod part 50. An end of the lower engagement recess 63 is connected to the lower end of the side engagement recess 62. As a result, the lower engagement recess 63 is directly connected to the side engagement recess 62.

[0047] As shown in FIGS. 9 to 12 , the load support member 9 has a communication recess 65 that connects the engagement recess 60 and the seating space S. The communication recess 65 is adjacent to the engagement recess 60 from the seating space S side. The communication recess 65 is formed so as to step down together with the engagement recess 60 from the surface of the load support member 9 where the engagement recess 60 opens. The communication recess 65 extends along the entire length of the engagement recess 60. The communication recess 65 opens from the surface of the load support member 9 where the engagement recess 60 opens to the inner surface facing the seating space S. For example, the portion of the communication recess 65 adjacent to the upper engagement recess 61 opens from the upper surface 45u of the upper connecting rod portion 45 to the inner surface 45i and steps down downward from the upper surface 45u. As a result, the open end of the engagement recess 60 opens to the seating space S side through the communication recess 65. The communication recess 65 is formed shallower than the engagement recess 60 when the plane of the load support member 9 where the engagement recess 60 opens is used as the reference.

[0048] As shown in FIGS. 1 and 5 , the upholstery material 70 is stretched over the load support member 9 to form a load support surface 8. The upholstery material 70 is stretched over the load support member 9 so that the load support surface 8 faces the torso of the seated occupant from the horizontal outer side. The upholstery material 70 is stretched over the upper connecting rod 45, the pair of upright rods 40, and the lower connecting rod 50. The upholstery material 70 includes a sheet body 71 and a hem material. The sheet body 71 is formed from a sheet material such as mesh fabric, knit fabric, or cloth. The sheet body 71 is formed by cutting the sheet material into a desired shape. In this embodiment, the sheet body 71 is formed in a rectangular shape corresponding to the shape of the frame-like portion of the load support member 9 consisting of the upper connecting rod 45, the pair of upright rods 40, and the lower connecting rod 50.

[0049] An edge material is bonded to the edge of the sheet body 71. The edge material forms the edge of the upholstery material 70. For example, the edge material is provided around almost the entire periphery of the edge of the upholstery material 70. The edge material is made of a material that is more rigid than the sheet body 71. The upholstery material 70 engages with the engagement recess 60 by inserting the edge material into the engagement recess 60 (see Figures 9 to 12). The edge material is provided on the upper edge 72, left and right side edges 73, and lower edge 74 of the upholstery material 70. The upper edge 72 of the upholstery material 70 engages with the upper engagement recess 61. The left and right side edges 73 of the upholstery material 70 engage with the side engagement recess 62. The lower edge 74 of the upholstery material 70 engages with the lower engagement recess 63. The outer peripheral edge of the upholstery material 70 is inserted into the engagement recess 60 around the entire periphery.

[0050] The sheet body 71 is pulled out from the engagement recess 60 through the communicating recess 65 toward the seating space S. The upholstery material 70 is positioned so that, when the sheet body 71 passes through the communicating recess 65, it does not protrude from the surface of the load support member 9 where the engagement recess 60 opens. When the sheet body 71 is pulled out from the engagement recess 60 toward the seating space S, the sheet body 71 is positioned so as not to cover the horizontally outer and upper corners 45a of the upper connecting rod 45. The upholstery material 70 exposes the majority of the entire length of the upper surface 45u of the upper connecting rod 45 so as to expose the outer edge of the upper surface 45u in a planar view. In this embodiment, the upholstery material 70 exposes the entire portion of the upper surface 45u of the upper connecting rod 45 that is outward in a planar view (opposite the seating space S) from the width center at all positions in the extension direction of the upper connecting rod 45. The seat body 71 covers the inner surface 45i of the upper connecting rod 45, the inner surfaces 40i of the pair of standing rods 40, and the inner surface 50i of the lower connecting rod 50 from the seating space S side. The seat body 71 closes the inner space of the frame body formed by the upper connecting rod 45, the pair of standing rods 40, and the lower connecting rod 50 from the seating space S side.

[0051] Here, the portion of the load support member 9 where the tension material 70 is tensioned is referred to as the tensioning portion 80. In this embodiment, the tensioning portion 80 is a frame-shaped portion consisting of the upper connecting rod portion 45, the pair of upright rod portions 40, and the lower connecting rod portion 50. The inner region 80a and the outer region 80b in the cross section of the tensioning portion 80 are defined as follows: The inner region 80a is the region that includes the end portion on the horizontal side of the seating space S. The outer region 80b is the region that includes the end portion on the opposite side of the seating space S in the horizontal direction.

[0052] FIG. 13 is a rear view showing the middle part in the left-right direction of the upper connecting rod part 45 of the embodiment. 9 and 13, the tensioning portion 80 includes an inner protrusion 81 provided in the inner region 80a and a handle portion 82 provided in the outer region 80b. The formation areas of the inner protrusion 81 and the handle portion 82 overlap with each other in the extension direction of the tensioning portion 80. However, the formation areas of the inner protrusion 81 and the handle portion 82 do not have to coincide with each other, and the formation area of ​​one of the inner protrusion 81 and the handle portion 82 may be wider than the formation area of ​​the other.

[0053] The inward protruding portion 81 protrudes further inward than the outer region 80b in the cross section of the tensioned portion 80. The inward protruding portion 81 is located on the opposite side of the seating space S across the load support surface 8 of the tensioned material 70, and extends along the back surface of the seat body 71.

[0054] The handle portion 82 is provided on the opposite side of the upholstery material 70, with the inward protruding portion 81 in between. The handle portion 82 has a convex shape in the cross section of the stretched portion 80 so that the user can hook their fingers around it. The handle portion 82 protrudes inward of the stretched portion 80 in the cross section of the stretched portion 80. The handle portion 82 is spaced apart from the inward protruding portion 81 in a direction away from the sheet body 71. As a result, a recessed portion 83 that opens inward is formed in the stretched portion 80. The recessed portion 83 receives the fingertips of fingers hooked on the handle portion 82.

[0055] In this embodiment, the inner protrusion 81 is the extension 48. That is, in this embodiment, the inner protrusion 81 and the handhold 82 are provided on the upper connecting rod 45. The inner protrusion 81 protrudes downward from the front of the backrest 47. The handhold 82 protrudes downward from the rear of the backrest 47. The handhold 82 extends in the left-right direction along the backrest 47. Because the inner protrusion 81 and the handhold 82 protrude downward from the backrest 47, they are convex when viewed from the front-to-back direction. The recess 83 opens on the underside of the upper connecting rod 45. Note that the handhold 82 does not have to protrude downward from the backrest 47, and may be formed on the backrest itself. For example, a recess may be formed on the underside of the backrest at a position behind the extension 48, and the rear wall of the recess in the backrest may be made convex, thereby allowing the convex portion to serve as a handhold. Alternatively, a rear and lower corner of the backrest may be used as a handhold without providing a recess behind the extension 48.

[0056] As described above, the backrest 7 comprises a pair of left and right standing rods 40 extending in the vertical direction, an upper connecting rod 45 connecting the upper ends of the pair of standing rods 40, and a tensioning member 70 stretched across the pair of standing rods and the upper connecting rod 45 to form the load support surface 8. The upper connecting rod 45 has a pair of front ends connected to the upper ends of the pair of standing rods 40, and a backrest 47 extending in the left-right direction in a plan view, and extending rearward from the pair of front ends. The upper connecting rod 45 is provided from the pair of front ends to the backrest 47, extends in the extension direction of the upper connecting rods 45, opens upward, and has an upper engagement recess 61 with which the upper edge 72 of the tensioning member 70 engages. Each of the pair of standing rod portions 40 has a side engagement recess 62 that extends along the extension direction of the pair of standing rod portions 40, opens forward, and engages with the upholstery material 70. The upper engagement recess 61 and the side engagement recess 62 are in communication with each other.

[0057] With this configuration, the stretching material 70 can be tensioned on the upper connecting rod 45 by engaging the upper edge 72 of the stretching material 70 with the upper engagement recess 61. Furthermore, the stretching material 70 can be tensioned on the upright rod 40 by engaging the side engagement recess 62. Here, because the upper engagement recess 61 opens upward, the stretching material 70 can be prevented from being positioned behind the upper connecting rod 45. Furthermore, because the side engagement recess 62 opens forward, the stretching material 70 can be prevented from being positioned outside the upright rod 40 in the left-right direction. Furthermore, because the upper engagement recess 61 and the side engagement recess 62 are connected to each other, the stretching material 70 can be engaged continuously from the upper engagement recess 61 to the side engagement recess 62, and the stretching material 70 can be prevented from protruding from between the upper engagement recess 61 and the side engagement recess 62. As a result, the upholstery material 70 is positioned closer to the space around the chair 1 than the rods 40, 45 of the backrest 7, preventing external contact, and the shape of the upholstery material 70 can be optimized.

[0058] The upper engagement recess 61 has a backrest engagement recess 61b provided in the backrest portion 47. The backrest engagement recess 61b is located forward of a corner 47a located at the upper rear end of the backrest portion 47. With this configuration, the upholstery material 70 is pulled out forward of the backrest portion 47 from the backrest engagement recess 61b, which is located forward of the upper rear end of the backrest portion 47. This prevents the upholstery material 70 from being positioned further rearward than the upper rear end position of the backrest portion 47, and makes it possible to suppress external contact of the upholstery material 70.

[0059] The upper surface 45u of the upper connecting rod 45 faces forward and upward at the backrest 47. This configuration makes it easier for the user to place their fingers on the upper rear end of the backrest 47 when gripping it. This prevents the user from touching the upholstery material 70, which is positioned further forward than the upper rear end of the backrest 47.

[0060] The backrest 7 is further provided with a lower engagement recess 63 that is located below the upper engagement recess 61 and behind the side engagement recess 62 and that holds the lower edge 74 of the upholstery material 70. With this configuration, the upper edge 72 of the upholstery material 70 is stretched over the upper connecting rod 45, the left and right side edge portions 73 of the upholstery material 70 are stretched over the pair of upright rods 40, and the lower edge 74 of the upholstery material 70 is held in the lower engagement recess 63, so no loose end is formed in the upholstery material 70. This ensures that the upholstery material 70 can retain its shape.

[0061] The backrest 7 further includes a lower connecting rod 50 that connects the pair of standing rods 40 together. The lower connecting rod 50 is connected to the standing rod 40 at a location lower than the connection with the upper connecting rod 45. The lower engagement recess 63 is formed in the lower connecting rod 50 and extends in the extension direction of the lower connecting rod 50. With this configuration, the upholstery material 70 can be tensioned on the lower connecting rod 50 by engaging the upholstery material 70 with the lower engagement recess 63. Furthermore, since the lower edge 74 of the upholstery material 70 is housed in the lower engagement recess 63, the appearance of the upholstery material 70 can be improved.

[0062] The present invention is not limited to the above-described embodiment explained with reference to the drawings, and various modifications are possible within the technical scope of the present invention. For example, in the above embodiment, the upper connecting rod 45 has the armrest 46 in addition to the backrest 47, but this configuration is not limiting. In other words, the upper connecting rod does not necessarily have to be provided with an armrest.

[0063] In the above embodiment, the open end of the engagement recess 60 is open to the seating space S through the communication recess 65, but this configuration is not limited thereto. That is, the load support member does not need to have a communication recess, and the engagement recess does not need to be open to the seating space S. Furthermore, the upholstery material 70 is arranged so that it does not protrude beyond the surface of the load support member 9 where the engagement recess 60 opens, as the sheet body 71 passes through the communication recess 65. However, if the load support member 9 does not have a communication recess 65, the upholstery material 70 may be arranged so that it protrudes beyond the surface where the engagement recess 60 opens. Even in this case, it is desirable that the upholstery material not protrude outward in the direction in which the load support surface widens in the cross section of the tensioned portion. For example, in the backrest portion 47, it is desirable that the upholstery material not protrude above the corners 47a.

[0064] In addition, the components in the above-described embodiments can be replaced with well-known components as appropriate, without departing from the spirit of the present invention. [Explanation of symbols]

[0065] 3...Support structure 5…za 7...Backrest 8...Load supporting surface 40…Standing rod part 45...Upper connecting rod part (connecting rod part) 47...Backrest 50...Lower connecting rod part 61...Upper engagement recess (first engagement recess) 61b...Backrest engagement recess 62...Side engaging recess (second engaging recess) 63...Lower engagement recess (auxiliary holding portion) 70…Tension material 72...Upper edge 74...Lower edge

Claims

1. A backrest that is supported by a support structure and has a load support surface that is above the seat and supports the weight of a seated person, a pair of left and right standing rod portions extending in the vertical direction; a connecting rod portion connecting the upper end portions of the pair of standing rod portions to each other; a tension member stretched between the pair of upright rod portions and the connecting rod portion to form the load support surface; Equipped with the connecting rod portion has a pair of front end portions connected to the upper end portions of the pair of upright rod portions, respectively, and a backrest portion extending along the left-right direction in a plan view, and extends rearward from the pair of front end portions; The connecting rod portion is provided from the pair of front end portions to the backrest portion, extends along the extending direction of the connecting rod portion, opens upward, and has a first engaging recess formed therein with which an upper edge portion of the upholstery material engages; Each of the pair of standing rod portions has a second engagement recess portion formed therein, the second engagement recess portion extending along the extension direction of the pair of standing rod portions and opening forward, and with which the upholstery material is engaged; The first engagement recess and the second engagement recess are in communication with each other. Backrest.

2. The first engagement recess has a backrest engagement recess provided in the backrest portion, The backrest engagement recess is located forward of the upper rear end of the backrest. The backrest according to claim 1.

3. The backrest portion has an upper surface facing forward and upward; The backrest according to claim 2.

4. A backrest as described in any one of claims 1 to 3, further comprising an auxiliary holding portion located below the first engagement recess and rearward of the second engagement recess, for holding the lower edge of the upholstery material.

5. Further provided is a lower connecting rod portion that connects the pair of standing rod portions to each other, the lower connecting rod portion is connected to the upright rod portion at a position lower than the connection portion with the connecting rod portion, The lower connecting rod portion is formed with a third engagement recess portion extending along the extending direction of the lower connecting rod portion, the auxiliary holding portion is the third engagement recess; 5. The backrest according to claim 4.

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