Chair backrest structure

Abstract

To make it possible to stretch a sheet-like felt over a back frame stereoscopically by performing heating / pressure treatment without molding in advance.SOLUTION: A sheet-like felt fixes two upper left and right parts to left and right side part frame upper parts of a back frame, respectively, and fixes a lower part to a back surface side of a joint part provided below the left, and right side part frames in the state that left and right both ends a little below a central part in a height direction are supported from a rear surface side by a support member fixed to the left and right side part frames, the felt is superposed stereoscopically to a front surface of the back frame. Also, on the left and right side part frames, an intermediate frame is integrally provided at an arbitrary height position between the upper frame and a fixing part of the support member in parallel to the upper frame, and the central part may be fixed to the central part of the intermediate frame in a width direction of the felt.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a chair back structure that uses a sheet of felt as a member that is attached to the front surface of a back frame. [Background technology]

[0002] From the viewpoint of effective utilization of resources, for example, used PET bottles are recycled to produce new PET bottles and PET fibers. Patent Document 1 discloses a technique for forming a chair seat using the above-mentioned recycled PET fibers. In Patent Document 1, a laminate is produced by laminating sheet-like PET woven fabric, PET film, and PET nonwoven fabric (felt), each of which contains recycled PET fibers, and the laminate is heated and pressurized using a molding die to form an L-shaped seat body integrated with the backrest. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-18570 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, it is necessary to subject the laminate containing the recycled PET fibers to a heat and pressure treatment, which causes problems in that the equipment is expensive and the manufacturing of the seating body requires a lot of time and effort. In addition, because the seat is pre-shaped to a specific three-dimensional shape, there are problems in that it may be necessary to drill holes after shaping, and fine adjustments when attaching it to the frame can be difficult. Furthermore, since the seat and the backrest are integrally formed, there is also the problem that it is not possible to replace only the backrest or only the seat.

[0005] In view of the above problems, the present invention aims to make it possible to attach a sheet-like felt containing recycled PET fibers to a back frame in a three-dimensional manner without having to pre-shape it through heat and pressure treatment. [Means for solving the problem]

[0006] In order to solve the above problems, in the present invention, the backrest of a chair is configured as follows. In other words, the backrest of the chair in the present invention is formed by stretching a sheet-like member onto the front of the back frame, and the back frame is formed in a frame-like shape integrally with an upper frame that curves gently toward the back side, left and right side frames that are connected vertically to the upper frame and curve gently toward the front side, and connecting portions provided at the lower parts of the left and right side frames, and a support member is fixed to the front of each of the left and right side frames slightly below the center in the height direction. The sheet-like member contains recycled PET fiber and has a thickness of 5 mm to 20 mm and a basis weight of 1000 to 3000 g / m 2 The seat cushion is made of felt, and its upper left and right parts are fixed to the upper parts of the left and right side frames in close proximity to the upper frame at two points, respectively, and its lower part is fixed to the back side of the connecting part with both left and right ends slightly below the center in the height direction supported from the back side by the supporting members, so that it is three-dimensionally attached to the front of the back frame.

[0007] In addition, an intermediate frame that gently curves toward the rear side may be integrally provided parallel to the upper frame at any height position between the upper frame and the fixing position of the support member on the left and right side frames, and the center of the felt in the width direction may be fixed to the center of the intermediate frame. Furthermore, the felt may be provided with a plurality of horizontal grooves along the height direction, a plurality of vertical grooves along the width direction, or a plurality of through holes in the portion supported by the support member. Also, a cover cushion may be attached to the front side of the backrest, and a hanger may be attached to the rear side of the upper portion of the back frame. Effect of the Invention

[0008] In the present invention, the sheet-like felt is fixed to the upper part of the left and right side frames of the back frame and the back side of the connecting part, respectively, and the left and right ends slightly below the center in the height direction are supported from the back side by the support members, so that the felt can be stretched three-dimensionally in a state where it is curved toward the back side in the width direction of the back frame and curved in a dogleg shape toward the front side in the height direction of the back frame. As a result, the felt does not need to be molded three-dimensionally by heating and pressurizing it using a molding die, which prevents the equipment from becoming expensive and reduces the effort and time required for manufacturing. Moreover, since the felt remains in sheet form, additional processing and fine adjustments during stretching can be easily performed. In addition, by providing an intermediate frame integrally with the upper frame and parallel to it at any height position between the upper frame and the fixing portion of the support member on the left and right side frames, and fixing the center of the felt in the width direction to the center of the intermediate frame, the curved state of the felt toward the back side can be more reliably ensured. Furthermore, if a plurality of lateral grooves are provided along the height direction at the portion of the felt that is supported by the support member, the felt can be easily deformed when supported by the support member. Furthermore, by providing a plurality of vertical grooves along the width direction of the felt, the felt can be easily deformed in the back direction. Furthermore, by providing a plurality of through holes in the felt, the breathability of the backrest can be improved, and in the case where no vertical grooves are provided, this can contribute to making the felt more easily deformable in the rearward direction. Furthermore, if a cover cushion is attached to the front surface of the backrest, the seat cushion will feel softer against the backrest, improving seating comfort and preventing the felt from getting dirty. Furthermore, if a hanger can be fixed to the back side of the upper frame, a jacket or the like can be hung on a chair without getting wrinkled. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a chair according to the present invention, seen from the front side; [Diagram 2] FIG. [Diagram 3] This is also a side view. [Figure 4] FIG. 2 is a perspective view of the backrest from the front side. [Diagram 5] FIG. 4 is an exploded perspective view showing an enlarged upper part of the backrest. [Figure 6] 2 is an exploded perspective view showing an enlarged view of the central portion of the backrest in the height direction. FIG. [Figure 7] FIG. 4 is an exploded perspective view showing an enlarged lower part of the backrest. [Figure 8] This is an oblique view of the back frame as seen from the front side. [Figure 9] 1 is a perspective view of the back frame as viewed from the rear side. [Figure 10] FIG. 4(a) is a side view showing the second cover body, and FIG. [Figure 11] FIG. 1(a) is a partially enlarged view showing the structure of the felt, and FIG. [Figure 12] 1A is a perspective view of the fixing member as viewed from the front side, FIG. 1B is a perspective view of the fixing member as viewed from the rear side, and FIG. 1C is a cross-sectional view of the fixing member. [Figure 13] 1A is a perspective view of the cap body as viewed from the front side, FIG. 1B is a perspective view of the cap body as viewed from the rear side, and FIG. 1C is a cross-sectional view of the cap body. [Figure 14]1A is a perspective view of the second fixing device as viewed from the front side, FIG. 1B is a perspective view of the second fixing device as viewed from the rear side, and FIG. 1C is a cross-sectional view showing the second fixing device. [Figure 15] 1A is a perspective view of the third fixing device as seen from the front side, FIG. 1B is a perspective view of the third fixing device as seen from the rear side, and FIG. 1C is a cross-sectional view showing the third fixing device. [Figure 16] FIG. 11 is an enlarged cross-sectional view showing a state in which a first fixing tool is fixed to an upper portion of the felt. [Figure 17] 13 is an enlarged cross-sectional view showing the upper part of the felt fixed to the upper part of the back frame. FIG. [Figure 18] FIG. 11 is a cross-sectional view showing the state in which the felt is fixed to the intermediate frame. [Figure 19] FIG. 11 is an enlarged cross-sectional view showing the state in which the felt is fixed to the intermediate frame. [Figure 20] 11 is an enlarged cross-sectional view showing a state in which a first cover body is fixed to a rear surface of the intermediate frame. FIG. [Figure 21] FIG. 11 is a cross-sectional view showing the state in which the felt is fixed to the intermediate frame. [Figure 22] FIG. 11 is an enlarged cross-sectional view showing a state in which a lower part of the felt is fixed to a second cover body. [Diagram 23] 13 is an enlarged cross-sectional view showing a state in which the second cover body is fixed to a lower part of the back frame. FIG. [Figure 24] FIG. 13 shows another embodiment of the felt. [Diagram 25] FIG. 11 is a perspective view showing another embodiment of a chair according to the present invention. [Figure 26] FIG. 11 is a perspective view showing still another embodiment of the chair according to the present invention. BEST MODE FOR CARRYING OUT THEINVENTION

[0010] Hereinafter, the best mode for carrying out the present invention will be described with reference to Fig. 1 to Fig. 26. Fig. 1 and Fig. 2 are perspective views showing one embodiment of a chair according to the present invention, Fig. 1 shows a state seen from the front side, Fig. 2 shows a state seen from the back side, and Fig. 3 is a side view of the same. As shown in Figures 1 to 3, a chair 1 according to the present invention is roughly composed of a five-legged leg body 2 with casters 2a attached to the tip portions, a seat support 3 rotatably mounted on the upper end of a leg pillar 2b erected in the center of the leg body 2, a seat body 4 attached to the upper portion of the seat support 3, and a backrest 5 attached to the rear end portion of the seat support 3.

[0011] The structure of the backrest 5 will be described with reference to Fig. 4 to Fig. 16. Fig. 4 is a perspective view of the backrest 5 seen from the front side, Fig. 5 is an exploded perspective view showing an enlarged upper part of the backrest 5, Fig. 6 is an exploded perspective view showing an enlarged central part of the backrest 5 in the height direction, and Fig. 7 is an exploded perspective view showing an enlarged lower part of the backrest 5. As shown in Figure 4, the backrest 5 is composed of a frame-shaped back frame 6 attached to the rear end of the seat support 3 and a sheet-shaped felt 7 that is three-dimensionally attached to the front side of the back frame 6. The back frame 6 is made of synthetic resin, and as shown in Figures 5 to 9, is formed so as to have a rectangular frame shape when viewed from the front and an L-shape when viewed from the side, and is integrally provided with an upper frame 61 that curves gently toward the rear, left and right side frames 62L, 62R that are connected vertically to the upper frame 61 and curve gently toward the front, a connection portion 63 with the seat support 3 provided at the bottom of the side frames 62L, 62R, and an intermediate frame 64 that is provided parallel to the upper frame 61 slightly above the center in the height direction of the side frames 62L, 62R and curves gently toward the rear.

[0012] The upper frame 61 and the left and right side frames 62L, 62R are formed to have a V-shaped cross-section, as shown in Figures 5 to 7, and at a position close to the upper frame 61 of the side frames 62L, 62R, a wall 62b is provided on part of the open front side, as shown in Figures 5 and 8, to provide a first fixing portion 62a having a triangular cylindrical shape in a plan view, which is used when attaching the felt 7. 6 and 8, a horizontally long cylindrical second fixing portion 64a is provided on the front side of the intermediate frame 64, which is used when attaching the felt 7, and a through hole 64b is provided on the back side of the second fixing portion 64a, as shown in Figures 6 and 9, for inserting a screw 95. In addition, hook-shaped locking portions 64c are drilled at four positions in the width direction of the intermediate frame 64 at intervals, as shown in Figures 6, 8 and 9. As shown in Figures 7 to 9, on the back side of the connecting portion 63, protrusion-like fourth fixing portions 63a used when attaching the felt 7 are protruded at two locations in the width direction with a gap between them, and below the fourth fixing portions 63a, as shown in Figures 7 and 9, a horizontally long slit 63b is provided.

[0013] In Figures 6 and 8, 65L, 65R are a pair of left and right support members fixed using screws 91 to the front of the side frames 62L, 62R, slightly below the center in the height direction, and support the ends of the felt 7 in the width direction from the back side when the felt 7 is attached. 6, reference numeral 66 denotes a first cover body fixed to the rear surface of the intermediate frame 64. As shown in FIG. 6, the first cover body 66 is formed in a U-shape when viewed from the side, and has locking hooks 66a protruding from four positions on the front side in the width direction at intervals. The first cover body 66 is fixed to the rear surface of the intermediate frame 64 by locking the locking hooks 66a from the rear surface with hook-shaped locking portions 64c provided on the intermediate frame 64. Further, in Fig. 7, 67 denotes a second cover body fixed to the back surface of the connecting portion 63. The second cover body 67 is formed in an L-shape in a side view as shown in Figs. 7 and 10, and pin-shaped third fixing portions 67a used when attaching the felt 7 are provided at two positions in the width direction at an interval from the front upper side of the vertical portion, and a horizontally long tongue-shaped piece 67b is provided obliquely upwardly on the inside of the corner portion to be inserted into a horizontally long slit 63b provided on the back surface side of the connecting portion 63. The third fixing portion 67a is formed in a shape of an arc at the top and a rectangular shape at the bottom as viewed from the front as shown in Fig. 10(b). In addition, a through hole 67c is provided on the tip side of the horizontal portion of the second cover body 67 for inserting a screw 96 (see Figure 7). With the tongue-shaped piece 67b inserted into the slit 63b of the connecting portion 63, the screw 96 is inserted into the through hole 67c and screwed into the back surface of the connecting portion 63, thereby fixing the second cover body 67 to the connecting portion 63.

[0014] On the other hand, as shown in FIG. 11(a), the felt 7 is made of, for example, a surface layer 7a and a base layer 7b, and is made by joining the surface layer 7a onto the base layer 7b by needle punching, to have a thickness of 5 mm to 20 mm and a basis weight of 1000 to 3000 g / m 2 The felt 7 may be formed in a sheet shape by bonding the surface layer 7a to both sides of the base layer 7b, and in this case, the thickness and basis weight may be within the above-mentioned ranges. The felt 7 uses recycled PET fiber as a part of the raw material.

[0015] 11(b), the felt 7 is punched to fit the shape of the back frame 6, and holes 71-74 are formed at predetermined positions to be used when attaching the felt 7 to the back frame 6. At this time, the width of the felt 7 is mostly aligned with the width of the back frame 6, but one portion (the lower side) is narrower than that. The felt 7 is fixed to the first to third fixing portions 62a, 64a, 67a provided on the back frame 6 using first to third fixing devices 80, 83, 84, and is thus three-dimensionally attached to the front of the back frame 6, as shown in Figures 4 to 7. The configuration of each of the fixing devices 80, 83, 84 will be described below with reference to FIGS.

[0016] The first fixing device 80 is used to fix the upper part of the felt 7 to the upper part of the back frame 6, and is composed of a triangular prism-shaped fixing member 81 shown in Figure 12 and a cap body 82 shown in Figure 13 that is paired with the fixing member 81. The fixing member 81 is disposed on the back surface side of the felt 7, and is inserted into the first fixing portion 62a provided on the side frames 62L, 62R of the back frame 6. As shown in Fig. 12, a cylindrical insertion portion 81a that is inserted into a hole portion 71 provided in the upper portion of the felt 7 is provided on the front side of the upper portion of the fixing member 81, and a through hole 81b is drilled in the insertion portion 81a for inserting a screw 92 (see Fig. 5) from the back surface side. The cap body 82 is disposed on the front surface side of the felt 7, and is fitted to the fixing member 81 disposed on the back surface side through the hole 71. As shown in Fig. 13, the cap body 82 includes a flange portion 82a that abuts on the front surface side of the felt 7, and a fitting portion 82b that protrudes integrally with the flange portion 82a, penetrates the hole portion 71 of the felt 7, and is fitted to the insertion portion 81a of the fixing member 81. The inside of the fitting portion 82b is substantially hollow, and an opening portion 82c is provided on one side thereof through which a fixing nut 93 (see Fig. 5) is inserted, and a through hole 82d is drilled on the back surface through which a screw 92 (see Fig. 5) that is screwed into the nut 93 is inserted.

[0017] The second fixing device 83 is intended to fix the felt 7 slightly above the center in the height direction and the center in the width direction to the second fixing portion 64a provided on the intermediate frame 64 of the back frame 6. 14, the second fixing device 83 includes a flange portion 83a that abuts against the front surface side of the felt 7, and a horizontally long fitting portion 83b that protrudes integrally with the flange portion 83a, penetrates a hole portion 72 provided in the felt 7, and is fitted into the second fixing portion 64a provided in the intermediate frame 64. Both left and right ends of the fitting portion 83b are substantially hollow, with an opening portion 83c provided at the top thereof into which a fixing nut 94 (see FIG. 6) is inserted, and a through hole 83d is drilled in the back surface thereof for inserting a screw 95 (see FIG. 6) that is screwed into the nut 94.

[0018] The third fixing tool 84 is for fixing the lower part of the felt 7 to a third fixing part 67 a provided on the second cover body 67 . 15, the third fixing device 84 includes a flange portion 84a that abuts against the surface side of the felt 7, and a fitting portion 84b that protrudes integrally with the flange portion 84a, penetrates a hole 73 provided in the felt 7, and is fitted to the third fixing portion 67a provided in the second cover body 67. The fitting portion 84a has an upper portion formed in an arc shape and a lower portion formed in a flat plate shape, and a slit 84c is formed in the middle position in the height direction, allowing it to expand somewhat when fitted to the third fixing portion 67a. In addition, a locking hook 84d is formed at the lower end of the fitting portion 84b.

[0019] Next, the method of attaching the felt 7 to the back frame 6 will be described with reference to FIGS. 5 to 7 and 16 to 23. Before attaching the felt 7 to the back frame 6, the support members 65L and 65R are fixed to the front side of the back frame 7 at predetermined positions using screws 91, as shown in FIGS.

[0020] 5 and 16, when attaching the felt 7 to the back frame 6, first, the insertion portion 81a of the fixing member 81 constituting one side of the first fixing device 80 is inserted from the back side into the holes 71 provided in two places on the left and right sides of the upper part of the felt 7, and the fitting portion 82b of the cap body 82 constituting the other side of the first fixing device 80 is penetrated from the front side and fitted into the insertion portion 81a of the fixing member 81. At this time, a fixing nut 93 is inserted in advance into the fitting portion 82b of the cap body 82 from an opening 82c provided on one side of it. In this state, a screw 92 is inserted from the rear side of the insertion portion 81a of the fixing member 81 through the through hole 81b provided on the rear side of the insertion portion 81a and through hole 82d provided on the rear side of the fitting portion 82b of the cap body 82, and screwed into the nut 93 inserted into the fitting portion 82b, thereby fixing the fixing member 81 and the cap body 82 together with the felt 7 sandwiched in between (see Figure 16(b)). Thereafter, as shown in FIG. 17, the lower portion of the fixing member 81 is inserted into the first fixing portion 62a provided on the side frames 62L, 62R of the back frame 6, thereby fixing the upper two points of the felt 7 to the upper two points of the back frame 6.

[0021] 6, 18 and 19, the fitting portion 83b of the second fixing device 83 is inserted from the front side into the hole 72 provided in the center in the width direction and slightly above the center in the height direction of the felt 7, and the fitting portion 83b is fitted into the second fixing portion 64a provided in the intermediate frame 64 of the back frame 6. At this time, fixing nuts 94 are inserted in advance into the fitting portion 83b through openings 83c provided at the upper left and right ends of the fitting portion 83b. In this state, a screw 95 is inserted from the rear side of the intermediate frame 64 through hole 64b provided on the rear side of the second fixing portion 64a and through hole 83d provided on the rear side of the fitting portion 83b of the second fixing tool 83, and screwed into a nut 94 inserted into the fitting portion 83b, thereby fixing the second fixing tool 83 and the intermediate frame 64 (second fixing portion 64a) with the felt 7 sandwiched between them (see FIG. 19). In this way, the felt 7 is fixed to the widthwise center of the intermediate frame 64 of the back frame 6, slightly above the heightwise center. 6 and 18, a first cover body 66 is attached from the back side of the intermediate frame 64, and as shown in Figures 20 and 21, locking hooks 66a provided at four locations in the width direction of the first cover body 66 are locked with hook-shaped locking portions 64c provided at four locations in the width direction of the intermediate frame 64, thereby fixing the first cover body 66 to the intermediate frame 64. This makes it possible to cover the back side of the intermediate frame 64.

[0022] Next, with the felt 7 slightly below the center in the height direction and both ends in the width direction supported from the back surface by the left and right support members 65L, 65R, as shown in Figures 7 and 22, the pin-shaped third fixing portion 67a protruding from the second cover body 67 is inserted from the back surface into the hole portion 73 provided on the lower side of the felt 7, and the fitting portion 84b of the third fixing device 84 is inserted from the front surface side and fitted into the third fixing portion 67a, and the locking hook 84d provided on the flat lower tip portion of the fitting portion 84b is engaged with the locking portion 67d provided on the back surface of the third fixing portion 67a, thereby fixing the third fixing portion 67a and the third fixing device 84 in a state where the felt 7 is sandwiched (see Figure 22(b)). Thereafter, as shown in Fig. 23, the second cover body 67, to which the lower side of the felt 7 is fixed by the third fixing tool 84, is fixed to the back side of the connecting part 63 of the back frame 6. At this time, as shown in Fig. 23(a), the protruding fourth fixing part 63a protruding from the front side to the back side of the connecting part 63 is inserted into the hole 74 located below the hole 73 of the felt 7, and as shown in Fig. 23(b), the tongue-shaped piece 67b protruding from the second cover body 67 is inserted into the slit 63b provided on the back side of the connecting part 63. In this state, as shown in Fig. 23(c), a screw 96 inserted through a through hole 67c provided at the tip of the second cover body 67 is screwed into the back side of the connecting part 63, whereby the second cover body 67 is fixed to the connecting part 63.

[0023] The procedure for fixing the lower side of the felt 7 to the back side of the connecting part 63 may be reversed from that described above. That is, first, the protruding fourth fixing part 63a protruding from the back side of the connecting part 63 is inserted into the hole 74 provided in the felt 7. Next, the third fixing part 67a protruding from the second cover body 67 is inserted into the hole 73 provided in the felt 7, and the third fixing tool 84 is fixed to the third fixing part 67a. At the same time, the tongue-shaped piece 67b protruding from the second cover body 67 is inserted into the slit 63b provided on the back side of the connecting part 63. In this state, the tip of the second cover body 67 may be screwed to the back side of the connecting part 63 with the screw 96.

[0024] As described above, in the present invention, the felt 7 is fixed to the first fixing portion 62a provided on the upper side of the left and right side frames 62L, 62R of the back frame 6, the second fixing portion 64a provided in the center of the intermediate frame 64, the third fixing portion 67a provided on the second cover body 67, and the fourth fixing portion 63a provided on the back side of the connecting portion 63, and the ends of the felt 7 in the width direction are supported from the back side by support members 65L, 65R at a position slightly lower than the center in the height direction of the back frame 6. Therefore, the felt 7 can be attached three-dimensionally in a curved state toward the back side in the width direction of the back frame 6 and in a L-shaped curve toward the front side in the height direction of the back frame 6. As a result, it is not necessary to mold the felt 7 into a three-dimensional shape by applying heat and pressure in advance using a mold, which prevents the equipment from becoming expensive and reduces the time and effort required for production. In addition, since the felt 7 remains in a sheet form, additional processing and fine adjustments during tensioning can be easily performed.

[0025] It should be noted that the chair 1 of the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in this embodiment, the intermediate frame 64 is provided slightly above the center in the height direction of the left and right side frames 62L, 62R of the back frame 6, but it may be provided at a position closer to the upper frame 61 or closer to the support members 65L, 65R. In other words, the intermediate frame 64 may be provided at any height position between the fixed portions of the upper frame 61 and the support members 65L, 65R. Also, the intermediate frame 64 may not be provided. In this case, the felt 6 may be fixed to the back frame 7 at two locations, top and bottom, and supported from the back surface side by the support members 65L, 65R. As a result, the structure of the back frame 6 can be simplified, and the number of parts can be reduced because the second fixing device 83 for fixing the felt 7 to the intermediate frame 64 is no longer necessary.

[0026] 24, the felt 7 may be provided with a plurality of lateral grooves 76 along the height direction at the portion supported by the support members 65L, 65R. The lateral grooves 76 may be provided on either the front or back surface of the felt 7, or on both surfaces. Providing the lateral grooves 76 makes it easier for the felt 7 to deform when supported by the support members 65L, 65R. 24(a), the felt 7 may be provided with a plurality of vertical grooves 77 along the width direction. The vertical grooves 77 may also be provided on either the front or back surface of the felt 7, or on both surfaces. By providing the vertical grooves 77, the felt 7 can be easily deformed toward the back surface. Furthermore, as shown in Fig. 24, the felt 7 may be provided with a plurality of through holes 75. The through holes 75 may be provided on the upper side of the felt 7 as shown in Fig. 24(b), or may be provided throughout the felt 7, or may be provided within a vertical groove 77 as shown in Fig. 24(a). Furthermore, the through holes 75 may all be the same size, or may be provided with different sizes. Providing the through holes 75 can improve the breathability of the backrest 5, and can also contribute to the ease of deformation of the felt 7 in the rear direction when the vertical groove 77 is not provided.

[0027] 25, a cover cushion 100 may be attached to the front side of the backrest 5. In this case, for example, the upper part of the cover cushion 100 may be formed into a bag shape, and this bag-shaped upper part may be attached to the upper part of the backrest 5, while the lower part may be fixed to the lower part of the back frame 6 using a third fastener 84. By attaching the cover cushion 100, the seat cushion 100 comes into soft contact with the backrest 5, improving seating comfort and preventing the felt 7 from getting dirty. 26, the back side of the upper frame 61 of the back frame 6 may be configured so that a hanger 110 can be fixed thereto. In this case, for example, a horizontally long mounting hole 61a may be provided on the back side of the upper frame 61 of the back frame 6, and a fixing portion 110a of the hanger 110 may be fitted into the mounting hole 61a, and then the hanger 110 may be fixed using a screw 97. By fixing the hanger 110, a jacket or the like can be hung on the backrest 5 without getting wrinkled. [Explanation of symbols]

[0028] 1 Chair bipedal body 2a Caster 2b pedestal 3 Seating 4. Seat 5. Backrest 6 Back frame 7. Felt 7a Surface material layer 7b Base material layer 61 Upper Frame 61a Mounting hole 62 Side Frame 62a 1st fixed part 62b wall 63 Connecting part 63a 4th fixed part 63b Slit 64 Intermediate Frame 64a 2nd fixed part 64b Through hole 64c Locking part 65 Support member 66 First cover body 66a Locking hook 67 Second cover body 67a 3rd fixed part 67b Lingulae 67c through hole 67d Locking part 71~74 Hole 75 Through hole 76 Yokomizo 77 Vertical groove 80 1st fixture 81 Fixing member 81a Insertion part 81b Through hole 82 Cap body 82a Tsuba 82b Mating part 82c opening 82d Through hole 83 Second fixture 83a Tsubabe 83b Mating part 83c opening 83d Through hole 84 Third fixture 84a Tsuba 84b Fitting part 84c slit 84d Locking hook 91,92,95,96,97 Screws 93,94 Nut 100 Cushion Cover 110 Hanger 110a Fixed part

Claims

1. A chair back structure having a sheet-like member attached to the front surface of a back frame, The back frame is formed in a frame shape integrally with an upper frame that is gently curved toward the back side, left and right side frames that are connected vertically to the upper frame and gently curve toward the front side, and connecting parts provided at the lower parts of the left and right side frames, and a support member is fixed to each of the left and right side frames on the front side slightly lower than the center in the height direction, The sheet-like member contains recycled PET fibers and has a thickness of 5 mm to 20 mm and a basis weight of 1000 to 3000 g / m ２ It is made of felt, The chair back structure is characterized in that the felt is fixed at two points on the upper left and right sides to the upper parts of the left and right side frames close to the upper frame, and the lower part is fixed to the back side of the connecting part while both left and right ends slightly below the center in the height direction are supported from the back side by the support members, thereby three-dimensionally stretching the felt on the front of the back frame.

2. The chair back structure according to claim 1, characterized in that an intermediate frame which is gently curved toward the back side is integrally provided parallel to the upper frame at any height position between the upper frame and the fixing portion of the support member on the left and right side frames, and the center of the felt in the width direction is fixed to the center of the intermediate frame.

3. 3. The chair back structure according to claim 1, wherein the felt has a plurality of horizontal grooves formed along a height direction at a portion supported by the support member.

4. 3. The chair back structure according to claim 1, wherein the felt has a plurality of longitudinal grooves formed therein along the width direction.

5. 3. The chair back structure according to claim 1, wherein the felt is provided with a plurality of through holes.

6. 3. The chair back structure according to claim 1, wherein a cover cushion is attached to the front side of the backrest.

7. 3. The chair back structure according to claim 1, wherein a hanger can be fixed to the rear side of the upper portion of the back frame.

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