Backrest and chair

Abstract

To provide a backrest capable of suppressing exposure of a shape of a rear part of a backrest structure part, and a chair.SOLUTION: A backrest 2 includes: a backrest structure 20 supporting a load of a sitter; and an upholstery material 50 which has a front side upholstery material part 51 covering a front side of the backrest structure 20 and a rear side upholstery material part 52 covering a rear side. The backrest structure 20 has: a vertical extension part 240 extending vertically; an upper part overhang part 246 overhanging backward from an upper part of the vertical extension part 240; and a lower part overhang part 313 overhanging backward from a lower part of the vertical extension part 240. An upper part of an upholstery material 50 is supported by the upper part overhang part 246, and a lower part of the upholstery material 50 is supported by the lower part overhang part 313. An upholstery material rear face part 523 between the upper part and the lower part of the upholstery material 50 is arranged at the back of the vertical extension part 240 with a space S1.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Conventionally, as a backrest of a chair used for office work or the like, a backrest frame covered with a bag-shaped stretching material is known. In the backrest described in Patent Document 1, the backrest structure portion such as the backrest frame includes a pair of left and right side frames, a top frame, an upper frame, and a lower frame that connect the upper, vertical middle, and lower portions of the pair of side frames, respectively, and an intermediate frame that connects the horizontal middle of the upper frame and the horizontal middle of the lower frame. The lower end portion of the stretching material is open, and the stretching material is covered from above with respect to the backrest structure portion. The stretching material is stretched with respect to the backrest structure portion such that the front surface portion of the stretching material follows the front surface of the backrest structure portion and the rear surface portion of the stretching material follows the rear surface of the backrest structure portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the backrest of the chair described in Patent Document 1, since the rear surface portion of the stretching material is stretched along the rear surface of the frame-shaped backrest structure portion, if there are irregularities on the rear surface of the backrest structure portion, the stretching material follows the irregularities, and the rear surface shape of the backrest structure portion is exposed, resulting in a problem of poor design.

[0005] Therefore, the present invention has been made in view of the above circumstances, and provides a backrest and a chair capable of suppressing the exposure of the shape of the rear portion of the backrest structure portion.

Means for Solving the Problems

[0006] In order to achieve the above object, the present invention adopts the following means. That is, the backrest according to the present invention includes a backrest structure that supports the load of the seated person, and a tension member having a front tension member portion that covers the front side of the backrest structure and a rear tension member portion that covers the rear side. The backrest structure has a vertically extending upper and lower extending portion, an upper overhanging portion that projects rearward from the upper portion of the upper and lower extending portion, and a lower overhanging portion that projects rearward from the lower portion of the upper and lower extending portion. The upper portion of the tension member is supported by the upper overhanging portion, the lower portion of the tension member is supported by the lower overhanging portion, and the rear tension member surface of the tension member between the upper portion and the lower portion is arranged with a space behind the upper and lower extending portion. Moreover, the vertically extending portions are arranged approximately at the center in the left-right direction of the backrest structure, and the rear surface portion of the tension member does not contact the vertically extending portions. 。

[0007] In the backrest configured as described above, the upper overhanging portion projects rearward from the upper portion of the upper and lower extending portion, and the lower overhanging portion projects rearward from the lower portion of the upper and lower extending portion. The upper portion of the tension member is supported by the upper overhanging portion, the lower portion of the tension member is supported by the lower overhanging portion, and the rear tension member surface of the rear tension member portion is arranged with a space behind the upper and lower extending portion. Therefore, since the upper and lower extending portion of the backrest structure is arranged in front of the rear tension member surface of the tension member, the rear tension member surface does not contact the rear surface of the upper and lower extending portion, and the exposure of the shape of the rear portion of the upper and lower extending portion can be suppressed.

[0008] Further, in the backrest according to the present invention, the backrest structure may have a backrest main body in which a load support surface for receiving the load from the seated person is formed on the front surface and a reinforcing portion is provided at the rear portion.

[0009] In the backrest configured as described above, since a reinforcing portion is provided at the rear portion of the backrest main body, it is possible to resist the moment that attempts to deform the backrest main body caused by the tension of the tension member. Therefore, while ensuring the space formed behind the upper and lower extending portion, it is possible to obtain a backrest that exhibits a suitable seating feeling with a stable shape of the load support surface.

[0010] In addition, in the backrest according to the present invention, the backrest structure may be connected to the rear part of the backrest body so as to support the backrest body from behind, and may have a backrest support as the reinforcing part.

[0011] In the backrest configured in this way, by making the reinforcing part a backrest support separate from the backrest body, the degree of design freedom is increased. Therefore, the thickness and width of the backrest support can be appropriately set to achieve both a thickness that does not contact the rear tension member part and a strength that can reinforce the backrest body.

[0012] In addition, in the backrest according to the present invention, the backrest structure has a rear overhanging member provided with the lower overhanging part, and the rear overhanging member may be a separate member from the backrest body.

[0013] In the backrest configured in this way, the overhanging amount of the lower overhanging part to the rear can be adjusted separately from the backrest body. Therefore, the degree of design freedom regarding the overhanging amount of the lower overhanging part to the rear is increased, and the overhanging amount can be increased to more reliably secure the space formed behind the vertically extending part.

[0014] In addition, in the backrest according to the present invention, the backrest support may be provided with parts that function as the vertically extending part, the upper overhanging part, and the lower overhanging part.

[0015] In the backrest configured in this way, by processing the backrest support, parts that function as the vertically extending part, the upper overhanging part, and the lower overhanging part can be provided on the backrest support.

[0016] In addition, in the backrest according to the present invention, the backrest support is fixed to the backrest body and has a backrest support member provided with the vertically extending part and the upper overhanging part, and the rear overhanging member may be fixed to the backrest support member.

[0017] In the backrest configured as described above, the backrest support member provided with the upper and lower extending portions and the upper overhanging portion, and the rear overhanging member provided with the lower overhanging portion can be manufactured separately. Further, by making the rear overhanging member a separate member from the backrest support member, the degree of freedom in design regarding the amount of overhang of the lower overhanging portion to the rear can be increased. Therefore, the amount of overhang to the rear can be increased, and a larger space can be secured behind the upper and lower extending portions.

[0018] Further, in the backrest according to the present invention, a recess that is recessed forward is formed on the rear surface of the upper overhanging portion. A closing member is disposed in the recess, and the tension member may be disposed along the recess and sandwiched between the closing member and the recess.

[0019] In the backrest configured as described above, since the tension member is sandwiched between the recess of the upper overhanging portion and the closing member, the upper part of the tension member is fixed. Therefore, the upper part of the tension member does not flutter and fits well.

[0020] Further, in the backrest according to the present invention, a locking portion for locking the lower end portion of the tension member may be provided on the lower overhanging portion.

[0021] In the backrest configured as described above, since the lower end portion of the tension member is locked to the locking portion of the lower overhanging portion, the lower end portion of the tension member does not flutter and fits well.

[0022] Further, in the backrest according to the present invention, the tension member may be formed in a bag shape with an open bottom and stretched on the front side and the rear side of the backrest structure.

[0023] In the backrest configured as described above, since the tension member is formed in a bag shape with an open bottom, the tension member can be placed on the backrest structure from above, so the workability of attaching the tension member is good.

[0024] Further, the chair according to the present invention includes the backrest according to any one of the above.

[0025] In the chair configured as described above, the upper overhanging portion projects rearward from the upper part of the vertically extending portion, and the lower overhanging portion projects rearward from the lower part of the vertically extending portion. The upper part of the stretching member is supported by the upper overhanging portion, the lower part of the stretching member is supported by the lower overhanging portion, and the rear surface portion of the stretching member of the stretching member is disposed with a space behind the vertically extending portion. Therefore, since the vertically extending portion of the backrest structure is disposed in front of the rear surface portion of the stretching member of the stretching member, the rear surface portion of the stretching member does not contact the rear surface of the vertically extending portion, and the exposure of the shape of the rear portion of the vertically extending portion can be suppressed.

Effects of the Invention

[0026] According to the backrest and the chair according to the present invention, the exposure of the shape of the rear portion of the backrest structure portion can be suppressed.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0028] Hereinafter, with reference to FIGS. 1 to 9, a chair according to an embodiment of the present invention will be described. In the following description, for convenience of explanation, the direction in which a seated person sitting in the seat 17 in a normal posture faces forward is referred to as "front", and the opposite direction is referred to as "rear". Also, the up-down and left-right directions in the following description shall mean directions that coincide with the directions centered on the seated person when the seated person is sitting in the seat 17 in a normal posture. Note that at appropriate positions in the drawings, an arrow FR indicating the front, an arrow UP indicating the upper side, and an arrow LH indicating the left side are marked.

[0029] As shown in FIG. 1, the chair 100 according to the present embodiment includes legs 10 installed on the floor surface F, a box-shaped support base 15 installed on the upper part of the legs 10, a seat 17 attached to the upper part of the support base 15, a backrest 2 attached to the rear part of the support base 15 to support the back of the seated person, and armrests 19 extending from both side parts on the lower side of the seat 17 upward to the seat 17, on which the elbows or the tips of the arms of the seated person are placed.

[0030] The legs 10 have a multi-branched leg 11 with casters 11a and a leg post 12 that stands up from the central part of the multi-branched leg 11 and houses a gas spring (not shown) which is a lifting mechanism. The leg post 12 has an outer cylinder 13 and an inner cylinder 14. The outer cylinder 13 is non-rotatably fitted and supported by the multi-branched leg 11. The lower part of the inner cylinder 14 is horizontally rotatably supported by the outer cylinder 13. The upper part of the inner cylinder 14 is fixed to the support base 15. The support base 15 houses a lifting adjustment mechanism for the leg post 12 and a reclining mechanism for the backrest 2.

[0031] The backrest 2 has a backrest structure 20 (see Fig. 2) and a covering material 50 that covers the backrest structure 20. The backrest structure 20 receives the back of the seated person. As shown in Fig. 2, the backrest structure 20 has a backrest support (reinforcement part) 21 and a backrest body 40 supported by the backrest support 21.

[0032] The backrest support 21 supports the back of the seated person. The backrest support 21 has a backrest support member 22 and a rear overhanging member 30.

[0033] As shown in Fig. 3, the backrest support member 22 has an inner member 23 and an outer member 24.

[0034] The inner member 23 has an elongated shape in the vertical direction. The inner member 23 is formed in a flat plate shape. The plate surface of the inner member 23 faces substantially in the front-rear direction.

[0035] As shown in Fig. 4, the inner member 23 has an inner vertically extending portion (vertically extending portion) 230 and an inner upper overhanging portion (upper overhanging portion) 236. The inner vertically extending portion 230 has an inner curved upper portion 231, an inner curved lower portion 232, an inner lower portion 234, and an inner lower fixing portion 235.

[0036] The inner curved upper portion 231 is inclined so as to gradually face rearward as it goes upward. As shown in Fig. 3, a plurality of mounting holes 231a penetrating in the plate thickness direction are formed at intervals in the vertical direction substantially at the center in the width direction (left-right direction) of the inner curved upper portion 231. A plurality of mounting holes 231b penetrating in the plate thickness direction are formed at intervals in the vertical direction on both end sides in the width direction of the inner curved upper portion 231. A mounting hole 231d penetrating in the plate thickness direction is formed at the upper portion of the inner curved upper portion 231.

[0037] The inner lower curved portion 232 slopes gradually rearward as it extends downward from the lower end of the inner upper curved portion 231. The portion where the lower end of the inner upper curved portion 231 and the upper end of the inner lower curved portion 232 are connected has a curved shape protruding forward. Mounting holes 232a penetrating in the plate thickness direction are formed on both end sides in the width direction of the inner lower curved portion 232.

[0038] The inner lower portion 234 slopes gradually forward as it extends downward from the lower end of the inner lower curved portion 232. The portion where the lower end of the inner lower curved portion 232 and the upper end of the inner lower portion 234 are connected has a curved shape protruding rearward. As shown in FIG. 6, by curving the portion where the lower end of the inner lower curved portion 232 and the upper end of the inner lower portion 234 are connected so as to protrude rearward, the rear end portion 17a of the seat 17 can be positioned rearward, and the length of the seat 17 in the front-rear direction can be ensured to be long.

[0039] The inner lower fixing portion 235 extends downward from the lower end of the inner lower portion 234. A plurality of mounting holes 235a penetrating in the plate thickness direction are formed in the inner lower fixing portion 235.

[0040] As shown in FIG. 5, the inner upper overhanging portion 236 overhangs rearward from the upper end of the inner upper curved portion 231. A mounting recess 236b recessed forward is formed in the rear surface 236a facing rearward in the inner upper overhanging portion 236.

[0041] As shown in FIG. 3, the outer member 24 covers substantially the entire rear surface of the inner member 23. The outer member 24 is wider than the inner member 23 and has an elongated shape in the vertical direction. The outer member 24 is formed in a flat plate shape. The plate surface of the outer member 24 faces substantially in the front-rear direction.

[0042] The outer member 24 has an outer vertically extending portion (vertically extending portion) 240 and an outer upper overhanging portion (upper overhanging portion) 246. The outer vertically extending portion 240 has an outer upper curved portion 241, an outer lower curved portion 242, and an outer lower portion 244.

[0043] The outer upper curved portion 241 is inclined so as to gradually face rearward as it goes upward. The outer upper curved portion 241 is disposed behind the inner upper curved portion 231. As shown in FIG. 4, a plurality of mounting holes 241a that are recessed from the front surface to the rear surface are formed at substantially the center in the width direction (left - right direction) of the outer upper curved portion 241 in the vertical direction. The screw 231c is inserted into the mounting hole 231a of the inner upper curved portion 231 of the inner member 23 and screwed into the mounting hole 241a of the outer upper curved portion 241 of the outer member 24. Thus, the inner member 23 and the outer member 24 are connected.

[0044] The outer lower curved portion 242 is inclined so as to gradually face rearward as it goes downward from the lower end portion of the outer upper curved portion 241. The outer lower curved portion 242 is disposed behind the inner lower curved portion 232. The portion where the lower end portion of the outer upper curved portion 241 and the upper end portion of the outer lower curved portion 242 are connected has a curved shape protruding forward. As shown in FIG. 3, a mounting hole 242a penetrating in the plate thickness direction is formed in the outer lower curved portion 242.

[0045] As shown in FIG. 6, the outer lower portion 244 is inclined so as to gradually face forward as it goes downward from the lower end portion of the outer lower curved portion 242. The portion where the lower end portion of the outer lower curved portion 242 and the upper end portion of the outer lower portion 244 are connected has a curved shape protruding rearward. A plurality of mounting recesses 244a that are recessed forward are formed on the rear surface of the outer lower portion 244. A mounting hole 244b penetrating to the front surface of the outer lower portion 244 is formed at the bottom (the surface facing rearward) of the mounting recess 244a.

[0046] As shown in FIG. 3, a rear connecting portion 16 is provided at the rear part of the support base 15. The rear connecting portion 16 is part of a rotating member that rotates around the axis of a main shaft (not shown) facing the left - right direction with respect to the support base 15. As shown in FIG. 6, a bolt 244c is inserted through a mounting recess 244a of the outer lower part 244 of the outer member 24, a mounting hole 244b, a mounting hole 235a of the inner lower fixing portion 235 of the inner member 23, and a mounting hole 16a formed in the rear connecting portion 16, and a nut 16b is fastened to the bolt 244c. Thereby, the inner member 23 and the outer member 24 are integrally fixed to the rear connecting portion 16.

[0047] As shown in FIG. 3, the rear connecting portion 16 and the outer lower part 244 of the outer member 24 are covered from behind by a rear cover 248.

[0048] The outer upper projecting portion 246 projects rearward from the upper end portion of the outer curved upper part 241. The width of the outer upper projecting portion 246 is formed wider than the width of the outer curved upper part 241. Mounting holes 246h penetrating in the plate - thickness direction are formed on both sides in the left - right direction of the outer upper projecting portion 246.

[0049] As shown in FIG. 5, on the rear surface 246a facing rearward in the outer upper projecting portion 246, a plurality of recesses 246b recessed forward are formed at intervals in the left - right direction.

[0050] The recess 246b has a first recess 246c recessed forward from the rear surface 246a of the outer upper projecting portion 246, and a second recess 246e recessed forward from the bottom surface (the surface facing rearward) 246d of the first recess 246c. A mounting hole 246g penetrating to the front surface of the outer upper projecting portion 246 is formed on the bottom surface (the surface facing rearward) 246f of the second recess 246e.

[0051] As shown in FIG. 2, the rear projecting member 30 is fixed to the lower part of the outer member 24 and projects rearward from the outer member 24.

[0052] As shown in FIGS. 7 and 8, the rear overhanging member 30 has a lower annular portion 31, an upper arch portion 32, a central connecting portion 33, and a pair of side connecting portions 34.

[0053] The lower annular portion 31 is formed in an annular shape in plan view. The lower annular portion 31 has a front edge portion 311 and a curved portion 312.

[0054] As shown in FIG. 9, the front edge portion 311 has a curved shape in which the center in the width direction (left - right direction) bulges slightly rearward. The front edge portion 311 is disposed with a gap behind the rear end portion 17a of the seat 17.

[0055] As shown in FIG. 7, a pair of upward locking pieces 311a extending upward are provided at the center in the width direction of the front edge portion 311. The pair of upward locking pieces 311a are spaced apart in the front - rear direction. The upward locking pieces 311a are inclined upward as they go forward.

[0056] The curved portion 312 is in a semi - circular arc shape in plan view. The curved portion 312 has a shape that bulges rearward. The center in the width direction of the curved portion 312 is a first lower overhanging portion (lower overhanging portion) 313 that protrudes most rearward. The tip of the curved portion 312 is connected to the left - right ends of the front edge portion 311.

[0057] As shown in FIG. 8, locking grooves (locking portions) 316 that are recessed upward are formed on the lower surfaces of the front edge portion 311 and the curved portion 312. The locking grooves 316 are formed annularly along the extending direction of the front edge portion 311 and the extending direction of the curved portion 312.

[0058] The upper arch portion 32 is disposed above the lower annular portion 31. The upper arch portion 32 is formed in a substantially semi-circular arc shape in plan view. The upper arch portion 32 has a shape that bulges rearward. The center in the width direction of the upper arch portion 32 is the second lower overhanging portion (lower overhanging portion) 321 that protrudes most rearward. As shown in FIG. 6, the second lower overhanging portion 321 is disposed above and rearward of the first lower overhanging portion 313. As shown in FIG. 2, the tip of the upper arch portion 32 is disposed in front of the tip of the curved portion 312.

[0059] As shown in FIG. 7, the central connecting portion 33 connects the first lower overhanging portion 313 of the lower annular portion 31 and the second lower overhanging portion 321 of the upper arch portion 32. The central connecting portion 33 has an upward standing portion 331, a forward extending portion 332, and a fixing piece portion 333.

[0060] The upward standing portion 331 extends upward from the first lower overhanging portion 313 of the lower annular portion 31. The forward extending portion 332 extends forward from the second lower overhanging portion 321 of the upper arch portion 32. The upper end of the upward standing portion 331 is connected to the forward extending portion 332. The fixing piece portion 333 is provided at the front end of the forward extending portion 332.

[0061] As shown in FIG. 6, a mounting hole 333a penetrating in the front-rear direction is formed in the fixing piece portion 333. A bolt 333b is inserted through the mounting hole 333a of the fixing piece portion 333 into the mounting hole 242a of the outer curved lower portion 242 of the outer member 24, and a nut 242b is fastened to the bolt 333b. Thereby, the rear overhanging member 30 is connected to the outer member 24.

[0062] As shown in FIG. 7, the side connecting portion 34 connects the portion on the left side of the first lower overhanging portion 313 in the lower annular portion 31 and the portion on the left side of the second lower overhanging portion 321 in the upper arch portion 32. Thereby, the distance between the lower annular portion 31 and the upper arch portion 32 does not change.

[0063] The side connection part 34 connects a portion on the right side of the first lower overhanging part 313 in the lower annular part 31 and a portion on the right side of the second lower overhanging part 321 in the upper arch part 32. Thereby, the distance between the lower annular part 31 and the upper arch part 32 is prevented from changing.

[0064] As shown in FIG. 9, in the rear overhanging member 30, the backrest support member 22 of the backrest 2 is inserted into a portion surrounded by the annular interior of the lower annular part 31 and the upper arch part 32.

[0065] In this way, the rear overhanging member 30 is configured as a separate member with respect to the inner member 23, the outer member 24, and the backrest body 40. Thereby, the amount of overhang to the rear of the first lower overhanging part 313 and the second lower overhanging part 321 can be appropriately set regardless of the shapes of the inner member 23, the outer member 24, and the backrest body 40.

[0066] As shown in FIG. 2, the backrest body 40 is formed in a flat plate shape. The plate surface of the backrest body 40 faces substantially in the front-rear direction. The length of the backrest body 40 in the width direction (direction LH) is longer than the length of the backrest support member 22 in the width direction (direction LH). The backrest body 40 has a backrest curved upper part (vertically extending part) 401, a backrest curved lower part (vertically extending part) 402, and an upper rear overhanging part (upper overhanging part) 403.

[0067] As shown in FIG. 4, the backrest curved upper part 401 is inclined so as to gradually face rearward as it goes upward. The backrest curved upper part 401 is disposed in front of the inner curved upper part 231. The upper rear overhanging part 403 is disposed in front of the inner upper overhanging part 236 and above the outer upper overhanging part 246.

[0068] As shown in FIG. 3, a plurality of mounting holes 401a penetrating in the plate thickness direction are formed at intervals in the vertical direction and the horizontal direction at substantially the center in the width direction (left - right direction) of the upper part of the backrest bending 401. The mounting holes 401a and the mounting holes 231b of the inner member 23 are connected by a fixture (not shown). As a result, the middle part of the backrest body 40 in the vertical direction is fixed to the inner member 23.

[0069] At the center in the width direction of the upper part of the upper part of the backrest bending 401, a mounting hole 401b penetrating in the plate thickness direction is formed. As shown in FIG. 5, a screw 401c is inserted through the mounting hole 401b of the backrest bending upper part 401 and screwed into the mounting hole 231d of the inner bending upper part 231 of the inner member 23. As a result, the upper part of the backrest body 40 is fixed to the inner member 23.

[0070] In the backrest body 40, the part above the part fixed to the inner member 23 by the screw 401c is the upper rear overhanging part 403. And the rear end part 403a of the upper rear overhanging part 403 is located slightly rearward of the outer upper overhanging part 246 in a side view from the direction LH, and strongly abuts on the upper part of the second stretching member part 52 of the stretching member 50 described later. Therefore, the upper rear overhanging part 403 functions as the upper overhanging part of the present invention together with the inner upper overhanging part 236 and the outer upper overhanging part 246. Also, if either one of the upper rear overhanging part 403 and the outer upper overhanging part 246 protrudes greatly rearward with respect to the other, only either one of the upper rear overhanging part 403 and the outer upper overhanging part 246 may function as the upper overhanging part of the present invention.

[0071] On both sides in the left - right direction of the upper part of the backrest bending 401, mounting holes 401d penetrating in the plate thickness direction are formed. A screw 401e is inserted through the mounting hole 401d and screwed into the mounting hole 246h of the outer member 24. As a result, the upper part of the backrest body 40 is fixed to the outer member 24.

[0072] The lower part 402 of the backrest bend inclines gradually rearward as it goes downward from the lower end of the upper part 401 of the backrest bend. The lower part 402 of the backrest bend is disposed on the front side of the lower outer bend 242 of the outer member 24. The part where the lower end of the upper part 401 of the backrest bend and the upper end of the lower part 402 of the backrest bend are connected has a curved shape protruding forward.

[0073] A plurality of mounting holes 402a penetrating in the plate thickness direction are formed in the lower part 402 of the backrest bend at intervals in the left - right direction. Screws 402b are inserted into the mounting holes 402a and screwed into the mounting holes 232a of the inner member 23. Thereby, the lower part of the backrest body 40 is fixed to the inner member 23. In this way, the upper part 401 and the lower part 402 of the backrest bend fixed to the inner member 23 function as the upper - lower extending parts of the present invention together with the inner upper - lower extending part 230 and the outer upper - lower extending part 240.

[0074] As shown in FIG. 2, the tip of the upper arch part 32 is disposed with a slight gap behind the lower part 402 of the backrest bend. Thereby, when a load is applied to the backrest body 40, the backrest body 40 and the rear - overhanging member 30 can deform freely respectively.

[0075] As shown in FIG. 6, the lower end of the lower part 402 of the backrest bend is inserted from above between a pair of locking pieces 311a of the lower annular part 31 of the rear - overhanging member 30 and is sandwiched by the pair of locking pieces 311a. Thereby, the movement of the backrest body 40 in the front - rear direction and downward is restricted.

[0076] The front surfaces of the upper part 401 and the lower part 402 of the backrest bend are load - supporting surfaces 40a (see FIG. 4) for receiving the load from the back of the seated person.

[0077] As shown in FIG. 1, the tension member 50 covers substantially the entire surface of the backrest structure 20. In other words, the tension member 50 covers the front side, the rear side, the upper side, and both the left and right sides of the backrest structure 20. The tension member 50 is made of cloth such as a mesh.

[0078] The sheet member 50 has a first sheet member portion (front sheet member portion) 51 disposed on the front side and a second sheet member portion (rear sheet member portion) 52 disposed on the rear side. The left and right end portions and the upper end portion of the first sheet member portion 51 and the second sheet member portion 52 are continuous, and the lower end portion is open to form a bag shape.

[0079] As shown in FIG. 4, the first sheet member portion 51 is stretched along the front surface of the backrest main body 40 of the backrest structure 20. As shown in FIG. 6, an insertion member 512 is provided at the lower end portion of the first sheet member portion 51. The insertion member 512 and the lower end portion of the first sheet member portion 51 to which the insertion member 512 is attached are inserted and locked in the locking groove 316 of the front edge portion 311 of the rear overhanging member 30. Thereby, the lower end portion of the first sheet member portion 51 is fixed to the rear overhanging member 30.

[0080] As shown in FIG. 4, the second sheet member portion 52 is stretched behind the outer member 24 of the backrest structure 20. As shown in FIG. 5, the upper portion 521 of the second sheet member portion (the rear surface of the sheet member) 52 is disposed along the concave portion 246b of the outer member 24. A pressing member (closing member) 53 is disposed on the rear side of the upper portion 521 of the second sheet member portion 52. The pressing member 53 has a shape that opens rearward. The upper portion 521 of the second sheet member portion 52 is sandwiched in the front-rear direction between the concave portion 246b of the outer member 24 and the pressing member 53. A mounting hole 53a penetrating in the front-rear direction is formed in the pressing member 53. A screw 53b is inserted through the mounting hole 53a of the pressing member 53 and the through hole formed in the second sheet member portion 52 and screwed into the mounting hole 246g of the outer member 24. Thereby, the upper portion 521 of the second sheet member portion 52 is fixed to the outer member 24. A cap 54 is fitted to the rear portion of the pressing member 53.

[0081] As shown in FIG. 4, the lower portion 522 of the second sheet member portion 52 abuts (supports) against the second lower overhanging portion 321 of the rear overhanging member 30 and is bent forward, and then abuts (supports) against the first lower overhanging portion 313 and is further bent forward.

[0082] The rear tension member surface 523 between the upper part 521 and the lower part 522 of the second tension member part 52 is arranged with a space S1 left behind the outer vertical extension part 240 of the outer member 24.

[0083] As shown in FIG. 6, an insertion member 512 is provided at the lower end of the second tension member part 52. The lower end of the insertion member 512 and the second tension member part 52 to which the insertion member 512 is attached are inserted and locked in the locking groove 316 of the curved part 312 of the rear overhanging member 30. Thereby, the lower end of the second tension member part 52 is fixed to the rear overhanging member 30.

[0084] A space in the front-rear direction is formed between the locking groove 316 and the second lower overhanging part 321, and since the locking groove 316 is located below the second lower overhanging part 321, no tension acts on the insertion member 521 to try to escape vertically downward from the locking groove 316.

[0085] In the chair 100 configured in this way, the outer upper overhanging part 246 projects rearward from the upper part of the outer vertical extension part 240, and the first lower overhanging part 313 and the second lower overhanging part 321 project rearward from the lower part of the outer vertical extension part 240. The upper part 521 of the second tension member part 52 is supported by the outer upper overhanging part 246, the lower part 522 of the second tension member part 52 is supported by the first lower overhanging part 313 and the second lower overhanging part 321, and the rear tension member surface 523 of the second tension member part 52 is arranged with a space S1 left behind the outer vertical extension part 240. Therefore, since the outer vertical extension part 240 of the backrest structure 20 is arranged in front of the rear tension member surface 523 of the tension member 50, the rear tension member surface 523 does not come into contact with the rear surface of the outer vertical extension part 240, and the exposure of the shape of the rear part of the outer vertical extension part 240 can be suppressed.

[0086] In addition, since the backrest support 21 as a reinforcing part is provided at the rear part of the backrest main body 40, it is possible to resist the moment that attempts to deform the backrest main body 40 acting due to the tension of the stretching material 50. Therefore, while securing the space S1 formed behind the outer upper and lower extending parts 240, it is possible to obtain a backrest 2 that presents a suitable seating feeling with a stable shape of the load support surface 40a.

[0087] In addition, by making the reinforcing part the backrest support 21 that is separate from the backrest main body 40, the degree of design freedom is increased. Therefore, it is possible to appropriately set the thickness and width of the backrest support 21 to achieve both a thickness that does not contact the second stretching material part 52 of the stretching material 50 and a strength that can reinforce the backrest main body.

[0088] In addition, the amount of protrusion of the first lower protruding part 313 and the second lower protruding part 321 backward can be adjusted separately from the backrest main body 40. Therefore, the degree of design freedom regarding the amount of protrusion of the first lower protruding part 313 and the second lower protruding part 321 backward is increased, and the amount of protrusion can be increased to more surely secure the space S1 formed behind the outer upper and lower extending parts 240.

[0089] In addition, the inner member 23 can be processed to provide the inner upper and lower extending parts 230 and the inner upper protruding part 236. The outer member 24 can be processed to provide the outer upper and lower extending parts 240 and the outer upper protruding part 246. By fixing to the outer member 24, the rear protruding member 30 can be provided.

[0090] In addition, the backrest main body 40 formed with the load support surface 40a for receiving the load from the seated person and the backrest support 21 that supports the backrest main body 40 and is provided with the outer upper and lower extending parts 240, the outer upper protruding part 246, the first lower protruding part 313, and the second lower protruding part 321 can be manufactured separately.

[0091] In addition, the outer member 24 provided with the outer upper and lower extending portions 240 and the outer upper overhanging portion 246, and the rear overhanging member 30 provided with the first lower overhanging portion 313 and the second lower overhanging portion 321 can be manufactured separately. Further, by making the rear overhanging member 30 a separate member from the inner member 23 and the outer member 24, the degree of freedom in design regarding the amount of rearward overhang of the first lower overhanging portion 313 and the second lower overhanging portion 321 of the rear overhanging member 30 can be increased. Therefore, the amount of rearward overhang can be increased, and a larger space S1 formed behind the outer upper and lower extending portion 240 of the outer member 24 can be secured.

[0092] In addition, since the tension member 50 is sandwiched between the concave portion 246b of the outer upper overhanging portion 246 and the pressing member 53, the upper portion 521 of the tension member 50 is fixed. Therefore, the upper portion 521 of the tension member 50 does not flap and fits well.

[0093] In addition, since the lower end portion of the tension member 50 is locked in the locking groove 316 of the first lower overhanging portion 313, the lower end portion of the tension member 50 does not flap and fits well.

[0094] In addition, since the tension member 50 is formed in a bag shape with an open bottom, the tension member 50 may be placed on the backrest structure 20 from above, so the workability of attaching the tension member 50 is good.

[0095] (Modification example) Next, a chair according to a modification example of the present invention will be mainly described with reference to FIGS. 10 and 11. Among the configurations of the following modification examples, the same configurations as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0096] As shown in FIG. 10, in the chair of this modification example, the backrest 2A has a backrest structure 20A and a tension member 50A (see FIG. 11) that covers the backrest structure 20A. The backrest structure 20A has a configuration in which a backrest main body having a backrest support surface that receives the load from the back of the seated person and a backrest support body that supports the backrest main body from behind are integrated.

[0097] The backrest structure 20A is formed in a flat plate shape. The backrest structure 20A has an up-and-down extending portion 201, an upper overhanging portion 202, and a lower overhanging portion 203.

[0098] The up-and-down extending portion 201 extends in the up-and-down direction. The middle of the up-and-down extending portion 201 in the up-and-down direction has a shape that bulges forward.

[0099] The upper overhanging portion 202 projects rearward from the upper end portion of the up-and-down extending portion 201. The lower overhanging portion 203 projects rearward from the lower end portion of the up-and-down extending portion 201.

[0100] As shown in FIG. 11, the first sheet member portion 51 of the sheet member 50A is arranged along the front surface of the up-and-down extending portion 201. The second sheet member portion 52 of the sheet member 50A abuts on (is supported by) the rear end surface 202a of the upper overhanging portion 202 and abuts on (is supported by) the rear end surface 203a of the lower overhanging portion 203. The second sheet member portion 52 is stretched between the rear end surface 202a of the upper overhanging portion 202 and the rear end surface 203a of the lower overhanging portion 203. The second sheet member portion 52 is arranged with a space S1 left behind the up-and-down extending portion 201.

[0101] In the chair configured as described above, the upper overhanging portion 202 projects rearward from the upper part of the up-and-down extending portion 201, and the lower overhanging portion 203 projects rearward from the lower part of the up-and-down extending portion 201. The upper part of the second sheet member portion 52 of the sheet member 50A is supported by the upper overhanging portion 202, the lower part of the second sheet member portion 52 is supported by the lower overhanging portion 203, and the second sheet member portion 52 is arranged with a space S1 left behind the up-and-down extending portion 201. Therefore, since the up-and-down extending portion 201 of the backrest structure 20A is arranged in front of the sheet member rear surface portion 523 of the sheet member 50A, the sheet member rear surface portion 523 does not abut on the rear surface of the up-and-down extending portion 201, and the exposure of the shape of the rear portion of the up-and-down extending portion 201 can be suppressed.

[0102] Note that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0103] For example, in the embodiment described above, the tension member 50 is stretched on both the front and rear sides of the backrest structure 20, but the present invention is not limited thereto. The tension member may be stretched at least on the rear surface side of the backrest structure.

[0104] Also, in the embodiment described above, the backrest main body 40 is formed in a flat plate shape, but the present invention is not limited thereto. The backrest main body may be formed in a frame shape.

[0105] Also, in the embodiment described above, the rear overhanging member 30 is fixed to the outer member 24, but the present invention is not limited thereto. The rear overhanging member 30 may be fixed to the inner member 23 or the backrest main body 40.

[0106] Also, in the embodiment described above, the backrest support 21 as a reinforcing portion is configured separately from the backrest main body 40, but the present invention is not limited thereto. The reinforcing portion may be provided integrally with the backrest main body, such as a rib provided on the rear surface of the backrest main body.

[0107] In addition, within the scope not departing from the gist of the present invention, it is possible to appropriately replace the components in the above embodiment with well-known components, and the above-described modified examples may be appropriately combined.

Explanation of Reference Numerals

[0108] 2, 2A Backrest 17 Seat 20, 20A Backrest Structure 21 Backrest Support (Reinforcing Portion) 22 Backrest Support Member 23 Inner Member 24 Outer Member 30 Rear Overhanging Member 40 Backrest Main Body 40a Load Support Surface 50, 50A Tension Member 51 First Tension Member Portion (Front Tension Member Portion) 52 Second Tension Member Portion (Rear Tension Member Portion) 53 Pressing member (closing member) 100 Chair 201 Upper and lower extending part 202 Upper overhanging part 203 Lower overhanging part 230 Inner upper and lower extending part (upper and lower extending part) 236 Inner upper overhanging part (upper overhanging part) 240 Outer upper and lower extending part (upper and lower extending part) 246 Outer upper overhanging part (upper overhanging part) 246b Concave part 313 First lower overhanging part (lower overhanging part) 321 Second lower overhanging part (lower overhanging part) 401 Upper part of backrest curve (upper and lower extending part) 402 Lower part of backrest curve (upper and lower extending part) 403 Upper rear overhanging part (upper overhanging part) 521 Upper part 522 Lower part 523 Rear surface of tension member S1 Space

Claims

1. A backrest structure that supports the load of the seated person, and a tension member having a front tension member portion that covers the front side of the backrest structure and a rear tension member portion that covers the rear side, and the backrest structure has a vertically extending portion that extends in the vertical direction, an upper projecting portion that projects rearward from the upper part of the vertically extending portion, and a lower projecting portion that projects rearward from the lower part of the vertically extending portion, and the upper part of the tension member is supported by the upper projecting portion, and the lower part of the tension member is supported by the lower projecting portion, the rear tension member surface between the upper part and the lower part of the tension member is arranged with a space behind the vertically extending portion, the vertically extending portion is arranged substantially at the center in the left-right direction of the backrest structure, and the rear tension member surface is a backrest that does not contact the vertically extending portion.

2. The backrest structure has a backrest main body in which a load support surface for receiving the load from the seated person is formed on the front surface and a reinforcing portion is provided at the rear portion, according to Claim 1.

3. The backrest structure is connected to the rear portion of the backrest main body so as to support the backrest main body from the rear, and has a backrest support body as the reinforcing portion, according to Claim 2.

4. The backrest structure has a rear projecting member provided with the lower projecting portion, and the rear projecting member is a separate member from the backrest main body, according to Claim 2 or 3.

5. The backrest support body is provided with portions that function as the vertically extending portion, the upper projecting portion, and the lower projecting portion, according to Claim 3 or 4.

6. The backrest support body is fixed to the backrest main body and has a backrest support member provided with the vertically extending portion and the upper projecting portion, and the rear projecting member is fixed to the backrest support member, according to Claim 4.

7. On the rear surface of the upper projecting portion, a recess that is concave forward is formed, a closing member is arranged in the recess, and the tension member is arranged along the recess and is sandwiched between the closing member and the recess, according to any one of Claims 1 to 6.

8. The lower projecting portion is provided with a locking portion for locking the lower end portion of the tension member, according to any one of Claims 1 to 7.

9. The stretching material is formed in a bag shape with an opening at the bottom, and is stretched on the front side and the rear side of the backrest structure. The backrest according to any one of claims 1 to 8.

10. A chair comprising the backrest according to any one of claims 1 to 9.

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