Backrest and chair

Abstract

To provide a backrest which can reduce the number of components and can keep excellent seating feeling, and a chair.SOLUTION: A backrest body part 15 includes: a core material 2; and a tension material 3 which is formed of a bag shape having an insertion port 36 where the core material 2 is inserted and covers a surface of the core material 2. A backrest support part 16 includes: an outer peripheral rod part 4 which is provided along an outer peripheral part; and an extending part 5 which extends inward from the outer peripheral rod part 4 for fixing the core material 2. The tension material 3 has: a front side tension material 31 which has a front side edge part 311 constituting a part of an opening edge of the insertion port 36 and covers a front surface of the core material 2; and a back side tension material 32 which has a back side edge part 321 constituting a part of the opening edge of the insertion port 36 and covers a back surface of the core material 2. The front side edge part 311 and the back side edge part 321 are housed in a front side housing recessed part 91 and a back side housing recessed part 92 (housing recessed parts) formed between the outer peripheral rod part 4 and the core material 2 fixed on the extending part 5.SELECTED DRAWING: Figure 15

Description

[Technical Field]

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

[0002] A known chair backrest has a back frame along the periphery, an upholstery fixed to the front side of the back frame, and a lining fixed to the rear side of the back frame (see, for example, Patent Document 1). In such a backrest, the upholstery and rear upholstery each comprise a core board fixed to the back frame, and cushioning material and a covering sheet that cover the surface of the core material. The core material for the upholstery is fixed to a receiving metal fitting on the back frame from the front, and the core material for the rear upholstery is fixed to a receiving metal fitting on the back frame from the rear. The core material for the upholstery and the core material for the lining are arranged overlapping each other at the front and rear, with the receiving metal fittings on the back frame in between. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-70956 Summary of the Invention [Problem to be solved by the invention]

[0004] The backrest disclosed in Patent Document 1 has a core board for the front and rear upholstery that is fixed to the spine frame, and cushioning material and a covering sheet that cover the surface of the core material, which makes the structure complex and the number of parts large, making manufacturing management and product management cumbersome. Furthermore, the support brackets for the back frame are positioned so as to overlap the edges of the core material for the upholstery and the core material for the lining. Therefore, in the areas of the core material for the upholstery and the lining that do not overlap with the support brackets for the back frame, i.e., in areas other than the edges, a gap is created between the core material for the upholstery and the core material for the lining. This can cause the core material for the upholstery and the core material for the lining to shift relative to each other within the gap when the chair is in use, potentially resulting in a poor seating experience.

[0005] Therefore, an object of the present invention is to provide a backrest and a chair that can reduce the number of parts and maintain a good seating comfort. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the backrest of the present invention comprises a backrest main body portion that supports the back of a seated person, and a backrest support portion that supports the backrest main body portion, wherein the backrest main body portion is formed in a bag shape having a core material and an insertion opening through which the core material is inserted, and an upholstery material that covers the surface of the core material, and the backrest support portion has an outer peripheral rod portion that is provided along the outer periphery, and an extension portion that extends inward from the outer peripheral rod portion and to which the core material is fixed, and the upholstery material has a front edge portion that forms part of the opening edge of the insertion opening, a front upholstery material that covers the front surface of the core material, and a rear edge portion that forms part of the opening edge of the insertion opening, and covers the rear surface of the core material, and the front edge portion and the rear edge portion are accommodated in an accommodating recess formed between the outer peripheral rod portion and the core material fixed to the extension portion.

[0007] To achieve the above object, a chair according to the present invention comprises the above-mentioned backrest and a support structure that supports the backrest.

[0008] In the present invention, the upholstery material is bag-shaped and has an insertion opening through which the core material is inserted. This allows the front and rear upholstery materials to be attached to the core material as a single unit by inserting the core material into the upholstery material through the insertion opening and placing the upholstery material over the core material. In the present invention, the front and rear edges are accommodated in and fixed in position in the accommodation recesses formed between the outer peripheral rod portion and the core material fixed to the extension portion, so even if the upholstery material is bag-shaped, the positions of both the front and rear edges can be easily fixed by pulling the front and rear edges of the upholstery material placed over the core material and accommodating them in the accommodation recesses. As described above, in the present invention, there is no need to divide the core material into two core materials, one for fixing the front upholstery material and the other for fixing the rear upholstery material. In the present invention, the core can be made into one piece, and the upholstery material is a bag-shaped material in which the front and rear upholstery materials are integrated, so the number of parts can be reduced. When the core is divided, the divided core materials may shift relative to each other, which can affect the seating comfort, but in the present invention, the core is a single piece, so the seating comfort can be maintained good.

[0009] In the backrest according to the present invention, a rear edge plate material may be attached to the rear edge portion, and the rear edge plate material may be accommodated in the accommodation recess. In the backrest of the present invention, the outer peripheral rod portion has a horizontal rod portion to which the extension portion is connected on its lower side, the horizontal rod portion protruding rearward beyond the extension portion, the core material has a lower protrusion arranged below the extension portion, the lower protrusion portion protruding rearward beyond the extension portion, the accommodating recess has a front accommodating recess in which the front edge portion is accommodated and a rear accommodating recess in which the rear edge portion is accommodated, and the rear accommodating recess may be a recess that opens rearward and is surrounded by a portion of the horizontal rod portion that protrudes rearward beyond the extension portion, and a portion of the lower protrusion portion that protrudes rearward beyond the extension portion. In addition, the backrest of the present invention may have a core material having a first contact surface that can contact the extended portion from the front and rear directions, and a second contact surface that can contact the extended portion toward the outer rod portion.

[0010] With this configuration, the core material contacts the extension portion from two directions, the front-rear direction and the direction toward the outer circumferential rod portion, making it easy to position the core material and the extension portion and also preventing misalignment between the core material and the extension portion.

[0011] In addition, in the backrest of the present invention, the core material has a recess forming surface that forms the storage recess, the first contact surface is provided continuously with the second contact surface, and the recess forming surface may be provided continuously and flush with the second contact surface in the front-to-back direction.

[0012] With this configuration, the area of the core where the extension portion is located and the area where the storage recess is formed are continuous in the front-to-rear direction. Therefore, when fixing the core and the extension portion, the extension portion can be placed in a predetermined position by passing it through the area that will become the storage recess. Furthermore, by passing the extension portion through the area that will become the storage recess, the extension portion approaches the first and second contact surfaces of the core, making it easy to contact the first and second contact surfaces of the core, facilitating work. Furthermore, because the first and second contact surfaces are continuous, both the first and second contact surfaces can be brought into contact with the extension portion simultaneously, making work easy.

[0013] In addition, the backrest of the present invention may have a fixing member that fixes at least one of the front edge portion and the rear edge portion accommodated in the accommodation recess to at least one of the extension portion and the core material.

[0014] With this configuration, at least one of the front edge portion and the rear edge portion can be reliably fixed to at least one of the extension portion and the core material by the fixing member, and the position of the front edge portion or the rear edge portion fixed by the fixing member can be reliably fixed even if the front edge portion or the rear edge portion is not completely inserted into the accommodation recess.

[0015] In the backrest according to the present invention, the fixing member may be covered with the upholstery material.

[0016] With this configuration, the fixing member is not exposed to the outside, which improves the design and prevents users and other fixtures from coming into contact with the fixing member. It also prevents the fixing member from coming off or loosening due to contact by users or other fixtures.

[0017] In the backrest according to the present invention, the core material may have a protruding portion that protrudes into the accommodation recess and sandwiches the upholstery material between the core material and the backrest support portion.

[0018] With this configuration, the front and rear edges of the upholstery material contained in the storage recess come into contact with the protrusion, making it easier to position the front and rear edges and preventing the front and rear edges from shifting and coming out of the storage recess. [Effects of the Invention]

[0019] According to the present invention, the number of parts can be reduced and a good seating feeling can be maintained. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view of a chair according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. 2 is a perspective view of the core material as seen from the rear. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 2 is a perspective view of the backrest support portion seen from the rear. [Figure 6] FIG. 10 is a front view of the backrest support portion to which the core material is fixed. [Figure 7] FIG. 10 is a rear view of the backrest support portion to which the core material is fixed. [Figure 8] FIG. 8 is a cross-sectional view taken along line BB in FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view taken along line CC in FIG. [Figure 10] FIG. 8 is a cross-sectional view taken along the line DD in FIG. 7. [Figure 11] FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along the line EE in FIG. [Figure 13] FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along the line FF in FIG. 13. [Figure 15] 1 (corresponding to the cross section of line GG in FIG. 18). [Figure 16] 1 (corresponding to the cross section of line HH in FIG. 18). [Figure 17] 19 is a cross-sectional view taken along line II in FIG. 1 (corresponding to the cross-section taken along line II in FIG. 19). [Figure 18] FIG. 10 is a perspective view showing the positional relationship between the front edge plate material and the backrest support portion. [Figure 19] 10 is a perspective view showing the relationship between the rear edge plate material, the fixing portion, and the backrest support portion. FIG. [Figure 20] FIG. 10 is a vertical cross-sectional view of a backrest according to a second embodiment. [Figure 21] FIG. 10 is a vertical cross-sectional view of a backrest according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] (First embodiment) A backrest and a chair according to a first embodiment of the present invention will be described below with reference to FIGS. As shown in Fig. 1, the chair 1 according to the first embodiment has legs 11 placed on a floor surface F, a support base 12 installed at the upper ends of the legs 11, a seat 13 attached to the top of the support base 12 to support the buttocks of a seated person, and a backrest 14 supported by the support base 12 to support the back of the seated person. The legs 11 and the support base 12 correspond to the "support structure" of the present invention.

[0022] The front of a person seated in a normal posture on chair 1 is written as "front," the rear as "rear," and the direction connecting the front and rear (the direction of arrow Y in the drawing) is written as the "front-to-back direction." The left side of a person seated in a normal posture on chair 1 is written as "left," the right side as "right," and the direction connecting the left and right (the direction of arrow X in the drawing) is written as the "left-to-right direction." In the drawing, the up-down direction (height direction) is indicated by arrow X. The shape of each component as viewed from the front to back direction is referred to as the "front view shape," the shape as viewed from the left to right direction is referred to as the "side view shape," and the shape as viewed from the top to bottom direction is referred to as the "plan view shape." The shape of chair 1 is bilaterally symmetrical.

[0023] As shown in Figures 1 and 2, the backrest 14 has a backrest main body 15 that supports the back of a seated person, and a backrest support 16 that is supported by the support base 12 (see Figure 1) and supports the backrest main body 15. The backrest support part 16 is a generally U-shaped frame that opens downward. The backrest main body part 15 is disposed on the upper side inside the backrest support part 16. The upper edge of the backrest main body part 15 is fixed to the backrest support part 16.

[0024] The backrest main body 15 has a core material 2 and a covering material 3 that covers the surface of the core material 2. As shown in Figures 2 and 3, the core material 2 is in the form of a single plate. One surface of the core material 2 faces forward and the other surface faces rearward. The shape of the core material 2 in a front view is a horizontally elongated, approximately elliptical shape. The shape of the core material 2 in a front view is curved so that the center in the left-right direction protrudes further rearward than both left-right ends.

[0025] The vicinity of the upper edge of the core material 2 is fixed over the entire left-right direction to overlap with the front side of an extension portion 5 (described later) of the backrest support portion 16. The portion of the vicinity of the upper edge of the core material 2 that is fixed over the front side of the extension portion 5 is referred to as a fixing portion 21.

[0026] 3 and 4, a lower protrusion 23 is provided on the lower edge of the fixing portion 21, protruding rearward over almost the entire width in the left-right direction. The shape of the lower edge of the fixing portion 21 in a front view is the boundary between the fixing portion 21 and the portion of the core material 2 below it. The shape of the lower protrusion 23 in a front view is curved so that the center portion in the left-right direction protrudes upward more than the middle portion in the left-right direction. The lower protrusion 23 is in the shape of a plate that protrudes approximately perpendicular to the rear surface of the fixing portion 21.

[0027] An upper protrusion 22 is provided on the upper edge of the fixing portion 21, protruding rearward over the entire width in the left-right direction. The upper edge of the fixing portion 21 is the upper edge of the core material 2. The shape of the upper protrusion 22 in a front view is curved so that the central portion in the left-right direction protrudes upward more than both ends in the left-right direction. As shown in FIG. 4 , the upper protrusion 22 has a shape that gradually narrows in the vertical direction from the base end side (front side) to the tip end side (rear side). The upper surface 221 of the upper protrusion 22 is a surface that slopes gradually downward from the front side to the rear side. The lower surface 222 of the upper protrusion 22 is a surface that is approximately perpendicular to the rear surface of the fixing portion 21. A tip surface 223 that connects the tip end portions of the upper surface 221 and the lower surface 222 of the upper protrusion 22 is a surface that is approximately parallel to the rear surface of the fixing portion 21.

[0028] An intermediate ridge 24 is provided in the heightwise middle of the fixing portion 21, protruding rearward over substantially the entire length in the left-right direction. In FIG. 4 , the intermediate ridge 24 and the hook portion 27 are connected. The shape of the intermediate ridge 24 in a front view is curved so that the left-right central portion protrudes upward more than the left-right middle portion. Both left-right ends of the intermediate ridge 24 are connected from above to the vicinity of both left-right ends of the lower ridge 23. The intermediate ridge 24 is plate-shaped and protrudes substantially perpendicular to the rear surface of the fixing portion 21.

[0029] 3, a plurality of first ribs 25 protruding rearward are provided between the upper ridge 22 and the intermediate ridge 24 of the fixing portion 21. A plurality of second ribs 26 protruding rearward are provided between the intermediate ridge 24 and the lower ridge 23 of the fixing portion 21.

[0030] Two hook portions 27 protruding rearward are provided at a distance in the left-right direction between the upper protrusion 22 and the intermediate protrusion 24 of the fixing portion 21. The hook portions 27 have a base portion 271 protruding rearward from the rear surface of the fixing portion 21, and a claw portion 272 protruding upward from the tip portion (rear end portion) of the base portion 271. The upper ridge 22, the intermediate ridge 24, and the second rib 26 protrude further rearward than the first rib 25. The hook portion 27 protrudes further rearward than the upper ridge 22, the intermediate ridge 24, and the second rib 26. The lower ridge 23 protrudes further rearward than the hook portion 27.

[0031] The fixing portion 21 is provided with a plurality of first holes 28 spaced apart in the left-right direction for inserting first fixing members 81 (see FIG. 15 ) such as push rivets that fix the core material 2, the backrest support portion 16, and the front edge plate material 6 (described later) of the upholstery material 3. In this embodiment, five first holes 28 are provided in the fixing portion 21. The first holes 28 are provided between the upper protrusion 22 and the middle protrusion 24 of the fixing portion 21 at positions that do not interfere with the hook portion 27.

[0032] 2 and 5, the backrest support part 16 has an outer peripheral rod part 4 provided along the outer periphery of the backrest 14, and an extension part 5 extending inward from the outer peripheral rod part 4 to which the core material 2 is fixed. The inner side refers to the side that is the center of the outer periphery of the backrest 14 when viewed from the front. The outer peripheral rod 4 has a generally U-shaped front view that opens downward. The outer peripheral rod 4 has a horizontal rod 41 located at the upper end and extending in the left-right direction, and a pair of vertical rods 42, 42 extending downward from both left-right ends of the horizontal rod 41. As shown in FIG. 1 , the lower ends of the pair of vertical rods 42, 42 are connected to a shaft 121 provided on the base 12 below the seat 13. The shaft 121 supports the backrest support 16 so that it can rotate about an axis extending in the left-right direction. The shape of the horizontal rod portion 41 in a front view is curved so that the middle portion in the left-right direction protrudes upward more than both left-right ends. The shape of the horizontal rod portion 41 in a plan view is curved so that the middle portion in the left-right direction protrudes more rearward than both left-right ends. A plate-shaped extension portion 5 is connected to the lower part of the horizontal rod portion 41. The horizontal rod portion 41 has a larger dimension in the front-to-rear direction (thickness direction) than the extension portion 5. The extension portion 5 is connected to the middle portion of the horizontal rod portion 41 in the front-to-rear direction. The horizontal rod portion 41 protrudes both forward and backward more than the extension portion 5. As described above, as shown in Figures 6 and 7, the fixed portion 21 of the core material 2 overlaps the front side of the extension portion 5.

[0033] 8 to 10, the front surface 411 of the horizontal rod portion 41 is an inclined surface that gradually slopes forward from the bottom to the top. The front surface 54 of the extension portion 5 is continuous with the lower side of the front surface 411 of the horizontal rod portion 41. The surface of the portion of the horizontal rod portion 41 that protrudes rearward beyond the extension portion 5 is curved so that the middle portion in the height direction protrudes rearward more than the upper and lower portions. The lower surface of this portion faces downward. This surface of the horizontal rod portion 41 that faces downward and rearward beyond the extension portion 5 is referred to as the rear lower surface 412. The upper surface of the horizontal rod portion 41 is curved so that the middle portion in the front-to-rear direction projects upward more than the front and rear sides.

[0034] As described above, the extension portion 5 is plate-shaped. When viewed from the front, the shape of the extension portion 5 is curved such that the middle portion in the left-right direction protrudes upward more than both left-right ends. When viewed from the top, the shape of the extension portion 5 is curved such that the middle portion in the left-right direction protrudes more rearward more than both left-right ends. The front surface 54 of the extension portion 5 has a shape corresponding to the rear surface of the fixing portion 21. In this embodiment, the extension portion 5 extends downward from the horizontal rod portion 41.

[0035] The extension portion 5 is provided with two hook holes 51 spaced apart in the left-right direction, into which the hook portion 27 of the core material 2 is inserted and into which the claw portion 272 of the hook portion 27 is hooked. The extension portion 5 has multiple second hole portions 52 spaced apart in the left-right direction for inserting first fixing members 81 that fix the core material 2, the backrest support portion 16, and the front edge plate material 6 of the upholstery material 3. The extension portion 5 has multiple third hole portions 53 spaced apart in the left-right direction for inserting second fixing members 82 (see Figure 16) such as push rivets that fix the rear edge plate material 7 of the upholstery material 3 to the extension portion 5. The hook hole 51, the second hole 52 and the third hole 53 are provided at positions where they do not interfere with each other in the left-right direction. When the fixing portion 21 overlaps the front side of the extension portion 5, the hook portion 27 of the fixing portion 21 is inserted into the hook hole portion 51, and the second hole portion 52 overlaps with the first hole portion 28 of the fixing portion 21 in the front-rear direction.

[0036] To secure the core material 2 to the backrest support portion 16, the fixing portion 21 of the core material 2 is overlapped with the extension portion 5 from the front side. When the fixing portion 21 overlaps the front side of the extension portion 5, the base portion 271 of the hook portion 27 of the fixing portion 21 passes through the hook hole portion 51, and the claw portion 272 of the hook portion 27 is positioned on the rear surface 55 of the extension portion 5. The hook portion 27 of the fixing portion 21 is caught in the hook hole portion 51 of the extension portion 5, and the fixing portion 21 is secured to the extension portion 5. In other words, the core material 2 is secured to the backrest support portion 16.

[0037] When the core material 2 is fixed to the backrest support portion 16 as described above, the core material 2 and the backrest support portion 16 are arranged as follows. The lower edge of the extension portion 5 rests on the upper surface of the lower protrusion 23 of the fixed portion 21. The tip (rear end) of the lower protrusion 23 protrudes rearward beyond the rear surface 55 of the extension portion 5. The portion of the upper surface of the lower protrusion 23 on which the lower edge of the extension portion 5 rests is referred to as the front upper surface 231, and the portion of the upper surface of the lower protrusion 23 that protrudes rearward beyond the rear surface 55 of the extension portion 5 is referred to as the rear upper surface 232. The upper surface of the rear upper surface 232 of the fixed portion 21 faces the rear lower surface 412 of the horizontal rod portion 41. The front upper surface 231 of the lower protrusion 23 corresponds to the "second contact surface" of the present invention. The rear upper surface 232 of the lower protrusion 23 corresponds to the "recess forming surface" of the present invention. The rear upper surface 232 (recess forming surface) of the lower protrusion 23 is provided continuously to the rear side of the rear upper surface 232 (recess forming surface) of the lower protrusion 23.

[0038] The front surface 54 of the extension portion 5 faces the rear surface of the fixed portion 21. The front surface 54 of the extension portion 5 is in contact with the tip surface 241 of the intermediate protrusion 24 of the fixed portion 21 and the tip surface 261 of the second rib 26. The tip surface 241 of the intermediate protrusion 24 and the tip surface 261 of the second rib 26 correspond to the "first contact surface" of the present invention. The tip surface 261 (first contact surface) of the second rib 26 is provided continuously in front of the front upper surface 231 (second contact surface) of the lower protrusion 23. A small gap S3 is formed between the front surface 54 of the extension portion 5 and the tip surface 223 of the upper protrusion 22 of the fixed portion 21. A gap S1 is formed between the front surface 54 of the extension portion 5 and the first rib 25 of the fixed portion 21. The dimension in the front-rear direction of the gap S1 between the extension portion 5 and the first rib 25 is larger than the dimension in the front-rear direction of the gap S2 between the extension portion 5 and the upper protrusion 22. The gap S1 between the extension portion 5 and the first rib 25 is formed over the entire space between the upper protrusion 22 and the intermediate protrusion 24. A gap S2 is formed between the front surface 411 of the horizontal rod portion 41 and the upper surface 221 of the upper protrusion 22.

[0039] The recess that forms the space consisting of the gap S2 between the front surface 411 of the horizontal rod portion 41 and the upper surface 221 of the upper protrusion 22, the gap S1 between the extension portion 5 and the first rib 25, and the gap S3 between the extension portion 5 and the upper protrusion 22 is referred to as the front accommodating recess 91. The recess that is surrounded by the upper surface of the rear upper surface 232, the rear lower surface 412 of the horizontal rod portion 41, and the rear surface 55 of the extension portion 5 and opens rearward is referred to as the rear accommodating recess 92. In the drawings, the vertical extent of the rear accommodating recess 92 is indicated by the reference symbol 921.

[0040] As shown in Figure 2, the upholstery material 3 is bag-shaped and has an insertion opening 36 for inserting the core material 2 therein. The upholstery material 3 has a front upholstery material 31 that covers the front surface of the core material 2, and a rear upholstery material 32 that covers the rear surface of the core material 2. The front-side upholstery material 31 and the rear-side upholstery material 32 are joined at their respective lower edges and at their left and right side edges, but are not joined at their respective upper edges. The space between the unjoined upper edges of the front-side upholstery material 31 and the rear-side upholstery material 32 is the insertion opening 36 described above. When the core material 2 is inserted inside the upholstery material 3 and the front-side upholstery material 31 and rear-side upholstery material 32 are stretched with a predetermined tension, the upholstery material 3 covers the surface of the core material 2. The front upholstery material 31 and the rear upholstery material 32 may be separate upholstery materials, with their edges sewn or glued together, or may be manufactured as a single unit during production.

[0041] The upper edge of the front upholstery material 31 that forms the insertion opening 36 is referred to as the front edge 311. The upper edge of the rear upholstery material 32 that forms the insertion opening 36 is referred to as the rear edge 321. A front edge plate material 6 is attached to the front edge 311 of the front upholstery material 31. A rear edge plate material 7 is attached to the rear edge 321 of the rear upholstery material 32. The front-side upholstery material 31 of this embodiment has a cushion material 33 that covers the front surface of the core material 2, and a skin material 34 such as cloth or leather that covers the front surface of the cushion material 33. The rear-side upholstery material 32 has a skin material 35 such as cloth or leather that covers the rear surface of the core material 2. A cushion material may also be provided on the rear-side upholstery material 32. The materials of the front-side upholstery material 31 and the rear-side upholstery material 32 may be selected as appropriate.

[0042] 2, 11, and 12, the front edge plate material 6 is a plate-shaped member with its thickness direction extending in the front-to-rear direction. The front edge plate material 6 has a plate surface facing approximately in the front-to-rear direction. The front edge plate material 6 is elongated in the left-to-right direction. The front edge plate material 6 has a curved shape in a front view, with the left-right middle portion projecting upward more than both left-right ends. The front edge plate material 6 has a curved shape in a plan view, with the left-right middle portion projecting more rearward more than both left-right ends. As shown in FIG. 12 , the edges of the cushion material 33 and the skin material 34 of the front upholstery material 31 are fixed to the upper edge portion of the rear surface of the front edge plate material 6. Only the skin material 34 may be fixed to the front edge plate material 6, without the cushion material 33 of the front upholstery material 31 being fixed thereto. The cushion material 33 and the skin material 34 of the front upholstery material 31 wrap around from above the front edge plate material 6 to the front and extend downward. The front edge plate material 6 is provided with fourth holes 61 spaced apart in the left-right direction, into which the first fixing members 81 are inserted. The front edge plate material 6 is formed with cutouts 62 at positions that overlap with the hook portions 27 (see FIG. 3) and the hook hole portions 51 so as not to interfere with them.

[0043] 2, 13, and 14, the rear edge plate material 7 is a plate-like material with its thickness direction in the front-to-rear direction. The rear edge plate material 7 has a plate surface facing approximately in the front-to-rear direction. The rear edge plate material 7 is long in the left-to-right direction. The shape of the rear edge plate material 7 in a front view is curved so that the middle part in the left-right direction protrudes upward more than both left-right ends. The shape of the rear edge plate material 7 in a plan view is curved so that the middle part in the left-right direction protrudes more rearward more than both left-right ends. As shown in Figure 14, the edge of the skin material 35 of the rear upholstery material 32 is fixed to the upper edge part of the front surface of the rear edge plate material 7. The skin material 35 of the rear upholstery material 32 wraps around from above the rear edge plate material 7 to the rear and extends downward. The rear edge plate material 7 is provided with a plurality of fifth holes 71 spaced apart in the left-right direction, into which second fixing members 82 for fixing the rear edge plate material 7 to the extension portion 5 are inserted.

[0044] The upholstery material 3 houses the core material 2 inside, with the front edge 311 and rear edge 321 oriented so that they open upward at the top, and covers the surface of the core material 2. As shown in Figures 15 to 17, the front edge 311 of the front upholstery material 31 is housed in the front accommodation recess 91, and is positioned and fixed in position between the core material 2 and the extension portion 5. The rear edge 321 of the rear upholstery material 32 is housed in the rear accommodation recess 92, and is positioned and fixed in position between the rear lower surface 412 of the horizontal rod portion 41 and the rear upper surface 232 of the lower protrusion 23.

[0045] When the front edge portion 311 of the front upholstery material 31 is accommodated in the front accommodation recess 91, the front edge plate material 6 is positioned in the area between the upper protrusion 22 and the middle protrusion 24 in the front accommodation recess 91. As shown in FIG. 18 , the front edge plate material 6 overlaps the vicinity of the upper edge of the rear surface 55 of the extension portion 5 from the rear side. The fourth hole portion 61 of the front edge plate material 6 overlaps with the second hole portion 52 of the extension portion 5. The first hole portion 28 of the fixing portion 21 is positioned in front of the fourth hole portion 61 of the front edge plate material 6. The notch portion 62 of the front edge plate material 6 overlaps with the hook hole portion 51 of the extension portion 5.

[0046] The front edge plate material 6 is disposed below the upper protrusion 22. The upper protrusion 22 prevents the front edge plate material 6, housed between the upper protrusion 22 and the intermediate protrusion 24 (the gap S1 between the extension portion 5 and the first rib 25), from slipping out upward. The upper protrusion 22 corresponds to the "protrusion" of the present invention. If the cutout portion 62 of the front edge plate material 6 comes into contact with the hook portion 27 of the fixing portion 21, the front edge plate material 6 may be deformed, preventing the upper edge of the front edge plate material 6 from securely contacting the lower surface of the upper protrusion 22. Therefore, it is desirable to set the size of the cutout portion 62 of the front edge plate material 6 so as to leave a sufficient gap relative to the vertical and lateral dimensions of the hook portion 27 so as not to come into contact with the hook portion 27. The cushioning material 33 and the covering material 34 of the front upholstery material 31 pass through the gap S3 between the upper protrusion 22 and the extension portion 5 and the gap S2 between the front surface 411 of the horizontal rod portion 41 and the upper surface 221 of the upper protrusion 22, in the vicinity of the front edge plate material 6, and wrap around to the front of the core material 2, covering the front surface of the core material 2. The fourth hole 61 of the front edge plate 6 overlaps with the second hole 52 of the extension 5 of the first hole 28 of the fixing part 21 on the front side.

[0047] As shown in FIG. 19 , the rear edge plate material 7 accommodated in the rear accommodation recess 92 overlaps the extension portion 5 from the rear. The fifth hole portion 71 of the rear edge plate material 7 overlaps the third hole portion 53 of the extension portion 5. The upper edge portion of the rear edge plate material 7 is located below the rear lower surface 412 of the horizontal rod portion 41. The lower edge portion of the rear edge plate material 7 rests on the rear upper surface 232 that protrudes further rearward than the extension portion 5. Furthermore, the upper edge of the rear edge plate material 7, which is pulled upward by the tension of the rear upholstery material 32, may abut against the rear lower surface 412 of the horizontal rod portion 41.

[0048] The first hole 28 of the fixing portion 21, the fourth hole 61 of the front edge plate 6, and the second hole 52 of the extension portion 5 overlap in the front-to-rear direction, and the first fixing member 81 is inserted from the rear. This fixes the front edge plate 6 and the front upholstery member 31 to the core member 2 and the outer peripheral rod portion 4. The rear edge plate 7 is positioned behind the first fixing member 81. The third hole 53 of the extension portion 5 and the fifth hole 71 of the rear edge plate material 7 overlap in the front-to-rear direction, and the second fixing member 82 is inserted from the rear. This fixes the rear edge plate material 7 and the rear upholstery material 32 to the outer peripheral rod portion 4. The skin material 35 of the rear upholstery material 32 is positioned behind the second fixing member 82. The first fixing member 81 and the second fixing member 82 are not exposed to the outside.

[0049] The method of assembling the backrest 14 will now be described. First, the upholstery material 3 is placed over the core material 2. The upholstery material 3 is bag-shaped, and has the front edge plate material 6 and the rear edge plate material 7 attached to it. The front edge plate material 6 is housed between the upper ridge 22 and the middle ridge 24. At this point, only the front edge plate material 6 is locked to the core material 2, and the rear edge plate material 7 is not locked. Next, the core material 2 is fixed to the extension portion 5. The fixing portion 21 of the core material 2 is arranged so as to overlap the front surface 54 of the extension portion 5, and the hook portion 27 of the fixing portion 21 is inserted into the hook hole portion 51 of the extension portion 5 to be hooked. The lower edge portion of the extension portion 5 rests on the lower protrusion 23 of the fixing portion 21. A front storage recess 91 and a rear storage recess 92 are formed. The front edge plate material 6 is accommodated in the front storage recess 91 and sandwiched between the fixing portion 21 and the extension portion 5. The first fixing member 81 is inserted from the rear into the first hole 28 of the fixing portion 21, the fourth hole 61 of the front edge plate 6 and the second hole 52 of the extension portion 5 to fix the position of the front edge plate 6.

[0050] Next, the second fixing member 82 is inserted into the fifth hole 71 of the rear edge plate material 7 from between the rear edge plate material 7 and the skin material 35 of the rear upholstery material 32. The rear edge plate material 7 is stretched upward to taut the rear upholstery material 32, and the rear surface of the core material 2 is covered by the rear upholstery material 32. With the rear upholstery material 32 in a taut state, the front upholstery material 31 joined to the rear upholstery material 32 also becomes taut, and the front surface of the core material 2 is covered by the front upholstery material 31.

[0051] The rear edge plate material 7 is accommodated in the rear accommodation recess 92. By pushing the rear edge plate material 7 from above (from behind) the skin material 35 arranged along its rear surface, the second fixing member 82, which has been inserted in advance into the fifth hole 71 of the rear edge plate material 7, is inserted into the third hole 53 of the extension portion 5, and the position of the rear edge plate material 7 is fixed. In this manner, the backrest 14 is assembled.

[0052] Next, the functions and effects of the backrest 14 and chair 1 according to the first embodiment will be described with reference to the drawings. The backrest 14 according to this embodiment is bag-shaped and has an insertion opening 36 through which the core material 2 is inserted. As a result, the core material 2 is inserted into the upholstery material 3 through the insertion opening 36, and the front upholstery material 31 and the rear upholstery material 32 can be attached integrally to the core material 2 by placing the upholstery material 3 over the core material 2. The front edge 311 (front edge plate material 6) is accommodated in a front accommodation recess 91 formed between the outer periphery rod portion 4 and the core material 2 fixed to the extension portion 5, and its position is fixed, and the rear edge 321 (rear edge plate material 7) of the upholstery material 3 is accommodated in a rear accommodation recess 92 formed between the outer periphery rod portion 4 and the core material 2 fixed to the extension portion 5, and its position is fixed. Therefore, even if the upholstery material 3 is bag-shaped, the positions of both the front edge portion 311 and the rear edge portion 321 can be easily fixed by pulling the front edge portion 311 and the rear edge portion 321 of the upholstery material 3 placed over the core material 2 and storing them in the front storage recess 91 and the rear storage recess 92, respectively.

[0053] In this way, in the backrest 14 according to this embodiment, it is not necessary to divide the core material 2 into two pieces in order to fix the front-side upholstery material 31 and the rear-side upholstery material 32, respectively. In the backrest 14 and chair 1 according to this embodiment, the core material 2 of the backrest 14 can be made into one piece, and the upholstery material 3 is a bag body formed by bonding together the front upholstery material 31 and the rear upholstery material 32, thereby reducing the number of parts. When the core material of the backrest is divided, the divided core materials may shift relative to each other, which may affect the seating comfort, but in the backrest 14 and chair 1 according to this embodiment, the core material 2 of the backrest 14 is a single piece, so the seating comfort can be maintained favorably.

[0054] In the backrest 14 of this embodiment, the core material 2 has a tip surface 241 (first contact surface) of the intermediate protrusion 24 and a tip surface 261 (first contact surface) of the second rib 26 that contact the extension portion 5 from the front, and a front upper surface 231 (second contact surface) of the lower protrusion 23 that contacts the extension portion 5 from below (towards the outer rod portion 4). With this configuration, the core 2 comes into contact with the extension portion 5 from two directions, the front and the bottom, making it easy to position the core 2 and the extension portion 5. Furthermore, misalignment between the core 2 and the extension portion 5 can be prevented.

[0055] In the core material 2 of the backrest 14 in this embodiment, the tip surface 261 (first contact surface) of the second rib 26 is provided continuously to the front side of the front upper surface 231 (second contact surface) of the lower protrusion 23, and the rear upper surface 232 (recess forming surface) of the lower protrusion 23 which forms the rear accommodating recess 92 is provided continuously to the rear side of the front upper surface 231 (second contact surface) of the lower protrusion 23. With this configuration, the area of the core 2 where the extension portion 5 is disposed and the area where the rear accommodating recess 92 is formed are aligned in the front-to-rear direction. Therefore, when stacking the core 2 and the extension portion 5 front-to-rear, the extension portion 5 can be moved forward so that it passes through the area of the core 2 that will become the rear accommodating recess 92 (or the core 2 is moved rearward), thereby stacking the core 2 and the extension portion 5 in a predetermined position. Furthermore, because the extension portion 5 is disposed so that it passes through the area that will become the rear accommodating recess 92, the extension portion 5 can be easily brought into contact with the first and second contact surfaces of the core 2, making the work easier. Furthermore, because the first and second contact surfaces are continuous, both the first and second contact surfaces can be easily brought into contact with the extension portion 5 at the same time.

[0056] In the backrest 14 of this embodiment, a first fixing member 81 is provided to fix the front edge portion 311 (front edge plate material 6) accommodated in the front storage recess 91 to the extension portion 5, and a second fixing member 82 is provided to fix the rear edge portion 321 (rear edge plate material 7) accommodated in the rear storage recess 92 to the extension portion 5. With this configuration, the edge of the front-side upholstery material 31 and the edge of the rear-side upholstery material 32 can be reliably fixed to the extension portion 5 by the first fixing member 81 and the second fixing member 82. Even when the front edge 311 is not fully inserted into the front accommodating recess 91, the front edge 311 can be reliably fixed to the extension portion 5 by the first fixing member 81. Even when the rear edge 321 is not fully inserted into the rear accommodating recess 92, the rear edge 321 can be reliably fixed to the extension portion 5 by the second fixing member 82.

[0057] In the backrest 14 according to this embodiment, the core material 2 has an upper protrusion 22 (protrusion) that protrudes into the front accommodation recess 91 and sandwiches the upholstery material 3 between itself and the extension portion 5. With this configuration, the front edge 311 accommodated in the front accommodating recess 91 comes into contact with the upper protrusion 22, making it easier to position the front edge 311 and preventing the front edge 311 from shifting and coming out of the front accommodating recess 91.

[0058] (Second embodiment) Next, the second embodiment will be described based on the attached drawings. Components and parts that are the same as or similar to those in the first embodiment described above will be designated by the same reference numerals, and their explanation will be omitted. Only configurations that differ from the first embodiment will be described. 20 and 21, in a backrest 14B of a chair 1B according to the second embodiment, an extension portion 5B of a backrest support portion 16B is inserted into a recess 29 formed in the upper edge portion of a core material 2B. The core material 2B is a single piece. The extension portion 5B extends downward from the middle portion in the front-to-rear direction of the horizontal rod portion 41B of the outer peripheral rod portion 4B. The horizontal rod portion 41B protrudes forward and rearward beyond the extension portion 5B. The portion of the underside of the horizontal rod portion 41B that is forward of the extension portion 5B is referred to as the front lower surface 413, and the portion of the underside of the horizontal rod portion 41B that is rearward of the extension portion 5B is referred to as the rear lower surface 414. The recess 29 is provided in the middle in the front-to-rear direction of the upper end of the core 2B. Of the upper end surface of the core 2B, the part located in front of the recess 29 is referred to as a front upper end surface 291, and the part located behind the recess 29 is referred to as a rear upper end surface 292.

[0059] When the extension portion 5B is inserted into the recess 29, a front storage recess 91B is formed between the front lower surface 413 of the horizontal rod portion 41B and the front upper end surface 291 of the core material 2B, and a rear storage recess 92B is formed between the rear lower surface 414 of the horizontal rod portion 41B and the rear upper end surface 292 of the core material 2B.

[0060] Similar to the first embodiment, the upholstery material 3B is bag-shaped with the front upholstery material 31 and the rear upholstery material 32 joined together. The upholstery material 3B houses the core material 2B inside, with the front edge 311 sandwiched between the front lower surface 413 of the horizontal rod portion 41B and the front upper end surface 291 of the core material 2 and housed in the front storage recess 91B, and the rear edge 321 sandwiched between the rear lower surface 414 of the horizontal rod portion 41B and the rear upper end surface 292 of the core material 2 and housed in the rear storage recess 92B. In this way, the positions of the front edge 311 and the rear edge 321 of the upholstery material 3B covering the core material 2 are fixed. The core material 2B and the extension portion 5B are fixed with fixing members 93, 94 such as push rivets that reach the front and rear of the core material 2B and the extension portion 5B inside the recess 29.

[0061] 21 , the front edge 311 of the front-side upholstery material 31 is accommodated in the front-side accommodation recess 91B, and its tip may also be accommodated in the recess 29 of the core 2B, and may be sandwiched between the front surface of the extension portion 5B and the side surface of the recess 29. The rear edge 321 of the rear-side upholstery material 32 is accommodated in the rear-side accommodation recess 92B, and its tip may also be accommodated in the recess 29 of the core 2B, and may be sandwiched between the rear surface of the extension portion 5B and the side surface 294 of the recess 29. In such a case, the fixing members 93, 94 may be configured to fix the front edge 311 and the rear edge 321 between the core 2 and the extension portion 5B.

[0062] 22, the front edge 311 of the front upholstery material 31 may only be inserted into the front storage recess 91B without being inserted into the recess 29 of the core 2, and the rear edge 321 of the rear upholstery material 32 may only be inserted into the rear storage recess 92B without being inserted into the recess 29 of the core 2. In such cases as well, the positions of the front edge 311 and rear edge 321 of the upholstery material 3B covering the core 2 are fixed.

[0063] In the backrest 14B of the second embodiment, even if the extension portion 5B of the backrest support portion 16B is inserted into the recess 29 of the core material 2B, the upholstery material 3 is made bag-shaped, and the front edge portion 311 and the rear edge portion 321 of the upholstery material 3B covering the core material 2 are pulled and inserted into the front storage recess 91B and the rear storage recess 92B, respectively, so that the positions of the front edge portion 311 and the rear edge portion 321 can be easily fixed. Furthermore, in the backrest 14B according to the second embodiment, there is no need to divide the core material 2B into two pieces in order to respectively fix the front-side upholstery material 31 and the rear-side upholstery material 32. Therefore, in the backrest 14B according to the second embodiment, the core material 2 can be made into one piece, and the upholstery material 3B is a bag body formed by bonding the front-side upholstery material 31 and the rear-side upholstery material 32 together, so the number of parts can be reduced. Furthermore, since the core material 2B is a single piece, good seating comfort can be maintained.

[0064] Although the embodiments of the backrest and chair according to the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention. For example, in the above embodiment, the backrest support portion 16 is attached to the support base 12 so as to be rotatable, but it may also be fixed to the support base 12 so as not to rotate.

[0065] In the first embodiment described above, the front edge plate 6 and the rear edge plate 7 are provided on the front edge 311 and the rear edge 321 of the upholstery material 3, whereas in the second embodiment, the front edge plate 6 and the rear edge plate 7 as in the first embodiment are not provided on the front edge 311 and the rear edge 321 of the upholstery material 3B. Whether or not to provide the front edge plate 6 and the rear edge plate 7 on the front edge 311 and the rear edge 321 of the upholstery material 3, 3B may be determined as appropriate. If the front edge plate 6 and the rear edge plate 7 are provided, their shapes may be other than those described above. Furthermore, the front edge 311 and the rear edge 321 may be provided with rod-shaped or other edging materials instead of plate-shaped ones. Furthermore, the edging materials provided on the front edge 311 and the rear edge 321 may be divided into multiple pieces.

[0066] In the first embodiment described above, the core 2 has a first contact surface (tip surface 241 of the intermediate ridge 24 and tip surface 261 of the second rib 26) that contacts the extension portion 5 from the front, and a second contact surface (front upper surface 231 of the lower ridge 23) that contacts the extension portion 5 from below. The position and direction at which the core 2 and the extension portion 5 contact each other may be set as appropriate.

[0067] In the first embodiment described above, the tip end surface 261 (first contact surface) of the second rib 26 is provided contiguous to the front side of the front upper surface 231 (second contact surface) of the lower protrusion 23, and the rear upper surface 232 (recess forming surface) of the lower protrusion 23 that forms the rear accommodating recess 9 is provided contiguous to the rear side of the front upper surface 231 (second contact surface) of the lower protrusion 23. The surface where the fixing portion 21 and the extension portion 5 come into contact and the direction thereof may be set as appropriate.

[0068] In the first embodiment described above, the front edge portion 311 (front edge plate material 6) accommodated in the front accommodating recess 91 is fixed to the extension portion 5 and the core material 2 by the first fixing member 81, and the rear edge portion 321 (rear edge plate material 7) accommodated in the rear accommodating recess 92 is fixed to the extension portion 5 by the second fixing member 82. The front edge portion 311 and the rear edge portion 321 do not have to be fixed to the extension portion 5 and the core material 2 by the first fixing member 81 and the second fixing member 82. Furthermore, when the front edge portion 311 and the rear edge portion 321 are fixed by the first fixing member 81 and the second fixing member 82, they may be fixed to either or both of the core material 2 and the extension portion 5.

[0069] In the first embodiment described above, the core 2 is provided with an upper protrusion 22 that protrudes into the inside of the front storage recess 91 to position the front edge 311 and prevent it from coming off. The core 2 does not necessarily have to be provided with the upper protrusion 22, or a member may be provided in place of the upper protrusion 22 to position the front edge 311 and prevent it from coming off. The core 2 may also be provided with a protrusion that protrudes into the inside of the rear storage recess 92 to position the rear edge 321 and prevent it from coming off.

[0070] In the above embodiment, the extension portion 5 extends downward from the horizontal rod portion 41 of the outer peripheral rod portion 4, but it may also extend in the left-right direction from the vertical rod portion 42 of the outer peripheral rod portion 4. The extension portion 5 may have both a portion extending downward from the horizontal rod portion 41 and a portion extending in the left-right direction from the vertical rod portion 42, or may have only one of them. In this embodiment, the extension portion 5 is mostly connected to the horizontal rod portion 41 and partially connected to the vertical rod portion 42, but if the extension portion 5 is large enough to span both the horizontal rod portion 41 and the vertical rod portion 42, it may be connected to only one of the horizontal rod portion 41 and the vertical rod portion 42. [Explanation of symbols]

[0071] 1,1B chair 2,2B core material 3 Upholstery 4,4B Outer rod part 5,5B extension part 6 Front edge plate material 7 Rear edge plate material 14,14B Backrest 15,15B Backrest body 16,16B Backrest support part 21 Fixed part 22 Upper protrusion (protrusion) 31 Front upholstery 32 Back side upholstery 36 Insertion port 54 Front 55 Rear 81 First fixing member (fixing member) 82 Second fixing member (fixing member) 91 Front storage recess 92 Rear storage recess 93,94 Fixing member 231 Front top surface (second contact surface) 232 Rear upper surface (recessed surface) 241 Tip surface (1st contact surface) 261 Tip surface (1st contact surface) 311 Front edge 321 Posterior edge

Claims

1. a backrest main body portion that supports the back of a seated person; a backrest support portion that supports the backrest main body portion; and The backrest main body portion includes: A core material and The pouch is formed in a bag shape having an insertion opening through which the core material is inserted, and has a covering material that covers the surface of the core material, The backrest support portion includes: an outer periphery rod portion provided along the outer periphery; an extension portion extending inward from the outer peripheral rod portion to which the core material is fixed, The upholstery material is a front upholstery material having a front edge portion that forms a part of the opening edge of the insertion port and covering the front surface of the core material; a rear edge portion that forms a part of the opening edge of the insertion opening, and a rear upholstery material that covers the rear surface of the core material, The front edge portion and the rear edge portion are accommodated in an accommodating recess formed between the outer peripheral rod portion and the core material fixed to the extension portion.

2. A backrest as described in claim 1, wherein a rear edge plate material is attached to the rear edge portion, and the rear edge plate material is accommodated in the accommodating recess.

3. The outer peripheral rod portion has a horizontal rod portion to which the extension portion is connected on the lower side, The horizontal rod portion protrudes rearward from the extension portion, the core member has a lower protrusion disposed below the extension portion, The lower protrusion protrudes rearward beyond the extension portion, The accommodating recess is a front accommodating recess in which the front edge portion is accommodated; a rear accommodating recess in which the rear edge portion is accommodated, The backrest according to claim 1 or 2, wherein the rear storage recess is a recess that opens to the rear and is surrounded by a portion of the horizontal rod portion that protrudes rearward beyond the extension portion, the extension portion, and a portion of the lower protrusion that protrudes rearward beyond the extension portion.

4. The core material is a first contact surface that can come into contact with the extension portion from the front-rear direction; The backrest according to claim 1 , further comprising a second contact surface that is capable of contacting the extension portion toward the outer circumferential rod portion.

5. the core member has a recess forming surface that forms the accommodating recess, the first contact surface is provided continuously with the second contact surface, The backrest according to claim 4 , wherein the recessed portion is flush with the second contact surface in the front-rear direction.

6. The backrest according to any one of claims 1 to 5, further comprising a fixing member that fixes at least one of the front edge portion and the rear edge portion accommodated in the accommodation recess to at least one of the extension portion and the core material.

7. The backrest according to claim 6 , wherein the fixing member is covered by the upholstery material.

8. The backrest according to any one of claims 1 to 7, wherein the core material has a protruding portion that protrudes into the accommodation recess and sandwiches the upholstery material between the core material and the backrest support portion.

9. A backrest according to any one of claims 1 to 8, A chair having a support structure that supports the backrest.

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