chair

Abstract

To provide a chair configured to be able to flexibly adjust a strength / weakness degree for supporting the waist of a seated person with respect to a backrest in accordance with the physique or preference of the seated person.SOLUTION: The chair has a lumber support R capable of supporting the waist of a seated person via a meshed tension member on a backrest having the tension member laid tense between left and right side frame members 2. The lumber support R is provided with a lumber base RB installed between the left and right side frame materials 2 so as to be changeable in position in a vertical direction, and left and right lumber pads RP supported on the lumber base RB so as to be changeable in position in a horizontal direction.SELECTED DRAWING: Figure 34

Description

[Technical Field]

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

[0002] BACKGROUND ART Chairs have been known in the past that are provided with a lumbar support on the backrest that can support the lower back of a seated person (see, for example, Patent Document 1).

[0003] There are various known lumbar supports that are configured to be movable in the up and down direction relative to the backrest.

[0004] However, with conventional seat cushions, the variations in support for the lumbar region of the seated person were limited to vertical movement, and therefore the flexibility of support for the lumbar region to suit the physique and preferences of the seated person was not necessarily sufficient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-084336 A. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in light of the above circumstances, and aims to provide a chair with a suitable configuration that allows the strength of support for the lumbar region of the seated person to be flexibly adjusted to suit at least the physique and preferences of the seated person. [Means for solving the problem]

[0007] That is, the present invention has the following configuration.

[0008] The invention described in claim 1 is a chair having a backrest with a mesh-like tension member stretched between left and right side frame members, and a lumbar support attached to the backrest that can support the lumbar of a seated person via the tension member, the lumbar support comprising a lumbar base that is installed between the left and right side frame members so that its position can be changed in the vertical direction, and a lumbar pad that is supported on the lumbar base so that its position can be changed in the horizontal direction. The lumbar base has a through-hole at the center in the up-down direction that penetrates in the front-to-back direction and extends in the left-to-right direction, and the lumbar pad comprises a pad main body that is disposed between the upright member and the lumbar base and that can press the upright member from the rear, an operating body that is located on the rear side of the lumbar base and can be held by the user, and a connecting shaft that is interposed between the pad main body and the operating body and engages with the through-hole, and the lumbar pad can take a preparatory position that is a position when attached to the lumbar base, and a mounting position that is a position different from the preparatory position and in which the operating body is attached to the lumbar base, and the operating body passes through the through-hole from the front to the rear only when the lumbar pad takes the preparatory position. After the operating body is passed through the through-hole, the lumbar pad is rotated about the axis of the connecting shaft to change its position from the preparation position to the mounting position, whereby the lumbar pad is mounted to the lumbar base. The vertical dimension of the connecting shaft in the mounting position is set to a dimension that substantially matches the vertical width dimension of the through-hole. The lumbar base has a plate-like portion in which the through-hole is formed. The plate-like portion is pressed against the connecting shaft at least when the lumbar pad rotates and can be temporarily elastically deformed. The temporary elastic deformation of the plate-like portion allows the lumbar pad to change its position from the preparation position to the mounting position. It's a chair.

[0009] The invention described in claim 2 is the chair described in claim 1, wherein the lumbar pads are arranged in pairs on the left and right sides of the lumbar base.

[0010] The invention described in claim 3 is a chair described in claim 1 or 2, in which the left and right side frame materials are approximately L-shaped when viewed from the side and have a bent portion in the middle in the vertical direction, and the left and right ends of the lumbar base are attached near the bent portion.

[0013] Claim 4 The invention described in claim 1 is characterized in that the mounting position is rotated about the axis of the connecting shaft at an angle of approximately 90° with respect to the preparation position. 1, 2 or 3 This is the chair described. [Effects of the Invention]

[0016] As described above, according to the present invention, it is possible to provide a chair having a suitable configuration that allows the strength of support for the lumbar region of the seated person to be flexibly adjusted to suit at least the physique and preferences of the seated person. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view showing an embodiment of the present invention; [Figure 2] FIG. [Figure 3] FIG. [Figure 4]FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] Cross-sectional view taken along line AA in FIG. 7. [Figure 10] 8 is a cross-sectional view taken along line BB in FIG. 7. [Figure 11] FIG. [Figure 12] FIG. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. 2 is a perspective view of the embodiment as seen from the rear side. [Figure 16] 16 is a cross-sectional view taken along line CC in FIG. 15. [Figure 17] FIG. [Figure 18] FIG. [Figure 19] FIG. [Figure 20] FIG. [Figure 21] 22 is a cross-sectional view taken along line DD in FIG. 21. [Figure 22] FIG. 2 is a perspective view of the embodiment as seen from the rear side. [Figure 23] FIG. [Figure 24] FIG. 2 is an exploded perspective view of the embodiment as viewed from the rear side. [Figure 25] FIG. 2 is a perspective view of the embodiment as seen from the rear side. [Figure 26] FIG. 2 is a perspective view of the embodiment as seen from the rear side. [Figure 27] FIG. 4 is a front view illustrating the attachment of the lumbar pad in the embodiment. [Figure 28] FIG. [Figure 29] FIG. [Figure 30] 31 is a view seen from the direction of arrow E in FIG. 30. [Figure 31] FIG. 4 is a front view illustrating the movement of the lumbar support in the embodiment. [Figure 32] FIG. 4 is a front view illustrating the movement of the lumbar support in the embodiment. [Figure 33] FIG. 4 is a front view illustrating the movement of the lumbar support in the embodiment. [Figure 34] FIG. 4 is a front view illustrating the movement of the lumbar support in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described below with reference to FIGS.

[0019] In this embodiment, the present invention is applied to a swivel chair for business use (hereinafter simply referred to as "chair") that is suitable for use in an office or the like.

[0020] The chair comprises legs A, a support base B rotatably supported relative to the legs A, a seat C disposed on the support base B, a backrest E supported relative to the support base B via a back support (not shown) so as to be able to tilt backward, and a lumbar support R attached to the backrest E.

[0021] <<Legs A>> The leg A includes a plurality of leg blades a1 each having a caster a11 at its tip, and leg supports a2 erected at the base ends of the leg blades a1.

[0022] <<Support base B>> The support base B supports the seat C and the backrest E. The support base B is mainly composed of a support base main body 1, which is an integrally molded synthetic resin product. The support base main body 1 is connected to the upper end of the leg support a2.

[0023] <<Location C>> Seat C has a seating surface on which an occupant sits. Seat C is placed on support base B. Seat C comprises a seat support c1, also called an outer shell, and a seat body c2 having a seating surface and mounted on seat support c1. Seat C is supported on support base B via a seat support mechanism (not shown).

[0024] <<Back support (not shown)>> The back support is rotatably supported by a main shaft (not shown) relative to the support base B. The back support is interposed between the support base B and the backrest E, and between the support base B and the seat C.

[0025] <<Backrest E>> The backrest E comprises a back frame M attached to the back support and a mesh-like tension member P stretched over the back frame M.

[0026] The backrest E has a backrest surface pm that supports the back of the seated person from behind, and is formed by an upholstery member P that is mainly made of mesh fabric.

[0027] In this embodiment, a lumbar support R capable of supporting the lumbar region of a seated person from the rear is installed on the left and right side frame members 2 of the backrest E. Whether the lumbar support R is attached to the backrest E afterwards or detached from the backrest E, it can be done by simply temporarily bending the lumbar support R and engaging / disengaging the held portion r1 with the lumbar support holding portion N without using fasteners such as screws.

[0028] <Back frame M> The back frame M comprises left and right side frame members 2 each having a tension member mounting groove mz opening outward, an upper frame member 3 having a tension member mounting groove mz opening upward and connecting the upper parts of the left and right side frame members 2, a lower frame member 4 connecting the lower parts of the left and right side frame members 2, and an intermediate connecting frame member 5 having a tension member mounting groove mz opening downward and connecting the left and right side frame members 2 together while forming an upper cavity sa between the upper frame member 3 and a lower cavity sb between the lower frame member 4.

[0029] In this embodiment, the left and right side frame members 2, the upper frame member 3, the lower frame member 4, and the intermediate connecting frame member 5 that constitute the back frame M are integrally molded from synthetic resin.

[0030] The back frame M comprises an upper frame-shaped portion wa having an upper cavity sa formed therein by left and right side frame members 2, an upper frame member 3 and an intermediate connecting frame member 5, and a lower frame-shaped portion wb having a lower cavity sb formed therein by left and right side frame members 2, a lower frame member 4 and an intermediate connecting frame member 5.

[0031] The backrest E has a tensioning member P that can form the backrest surface pm stretched only on the upper frame-shaped portion wa provided on the back frame M. On the other hand, the tensioning member P is not stretched on the lower frame-shaped portion wb.

[0032] [Left and right side frame material 2] The left and right side frame members 2 extend in the vertical direction. The left and right side frame members 2 have a bent portion 23 in the middle in the vertical direction, and are generally V-shaped in side view.

[0033] On the outer surfaces of the left and right side frame members 2, tension member mounting grooves mz are formed, which continue from the upper ends of the side frame members 2 to a height position that roughly corresponds to the lower edges of the intermediate connecting frame member 5. A tension member P is stretched between the left and right side frame members 2 that extend in the vertical direction.

[0034] The left and right side frame members 2 are provided with an outer frame portion 21 having a tension member mounting groove mz opened outward, and an inner frame portion 22 located inside the outer frame portion 21 and with its front portion located further rearward than the front portion of the outer frame portion 21.

[0035] A lumbar support holding portion N is provided in the vertical middle portion of the left and right side frame members 2, which is at a height position corresponding to the waist of the seated person, more specifically, in the vertical middle portion of the inner frame portion 22 of the left and right side frame members 2, which can hold the lumbar support R in a manner that allows its vertical position to be changed.

[0036] The lumbar support holding portion N is located near the bending portion 23, which is a portion of the left and right side frame members 2 that is bent so as to convex forward in side view (a portion that is bent so as to form a U-shape and protrude forward in side view).

[0037] The inner frame portion 22 of the left and right side frame members 2 is provided with a rail portion n1 that protrudes forward and extends in the vertical direction, a groove portion n2 that opens toward the center of the backrest E in the horizontal direction and extends in the vertical direction, and a guide groove n3 that is provided further forward than the groove portion n2, opens toward the center of the backrest E in the horizontal direction and extends in the vertical direction.

[0038] The rail portion n1, groove portion n2, and guide groove n3 appear only by molding into the inner frame portions 22 of the left and right side frame members 2. In other words, the rail portion n1, groove portion n2, and guide groove n3 are formed without attaching any other separate or independent parts to the left and right side frame members 2.

[0039] The rail portion n1 has a front surface n11 facing forward, an outward surface n12 facing the outer frame portion 21, and an inward surface n13 facing the opposite side of the outward surface n12, i.e., the center side of the backrest E in the left-right direction.

[0040] The forward-facing surface n11 and the outward-facing surface n12 of the rail portion n1 are arranged to be approximately perpendicular to each other. Similarly, the forward-facing surface n11 and the inward-facing surface n13 of the rail portion n1 are arranged to be approximately perpendicular to each other. Furthermore, the outward-facing surface n12 and the inward-facing surface n13 of the rail portion n1 are arranged to be approximately parallel to each other. The rail portion n1 is adapted to engage with a rail engaging portion r11 provided on the lumbar base RB.

[0041] Between the rail portion n1 and the outer frame portion 21, a receiving groove n4 is formed that is open forward and receives an outwardly extending wall r112 that is formed on the outer end of the lumbar base RB and protrudes rearward.

[0042] The left rail portion n1 and the right rail portion n1 are formed so as to gradually move in a direction toward each other upward when viewed from the front. In other words, the left rail portion n1 and the right rail portion n1 are not arranged parallel to each other in the vertical direction.

[0043] The groove portion n2 is located rearward of the tip of the rail portion n1, i.e., the front-facing surface n11. The groove portion n2 has a rearward-facing surface n21 that is a rearward-facing portion that faces rearward. The groove portion n2 is formed behind the rail portion n1.

[0044] The groove portion n21 is a V-groove having a rearward surface n21 that is substantially parallel to the forward surface n11 of the rail portion n1. An engaging claw r12 provided on the lumbar base RB is adapted to engage with the groove portion n21.

[0045] The guide groove n3 constitutes a movement range restriction mechanism Q that restricts the vertical movement range of the lumbar support R relative to the backrest E. The guide groove n3 is disposed approximately parallel to the groove portion n2. The guide groove n3 is set to be longer in the vertical direction than the groove portion n2. A pair of guide protrusions r13 provided spaced apart above and below the lumbar base RB are adapted to engage with the guide groove n3. The guide groove n3 has a groove shape that corresponds to the guide protrusions r13, which have rounded tips.

[0046] [Top frame material 3] The upper frame member 3 extends in the left-right direction and includes an outer frame portion 31 having an upwardly open tension member mounting groove mz formed therein for mounting the tension member P, and an inner frame portion 32 disposed below the outer frame portion 31.

[0047] [Bottom frame material 4] The lower frame member 4 connects the lower portions of the left and right side frame members 2 and has a portion that is connected to the back support body via fasteners such as screws.

[0048] [Intermediate connection frame material 5] The intermediate connecting frame member 5 extends in the left-right direction and is installed between the portions of the left and right side frame members 2 that are tilted forward when viewed from the side. The intermediate connection frame member 5 has a curved shape that is convex toward the rear in a plan view. The intermediate connection frame member 5 is formed with a tension member mounting groove mz that opens downward.

[0049] <Upholstery material P> The upholstery member P is mainly made of a mesh-like fabric that can form the backrest surface pm.

[0050] The peripheral edge of the tensioning member P is attached to a tensioning member attachment groove mz provided in the upper frame-shaped portion wa of the back frame M. The tensioning member P is stretched over the front side of the upper frame-shaped portion wa of the back frame M.

[0051] <<Lumbar Support R>> The lumbar support R is supported by the backrest E in a detachable manner.

[0052] The lumbar support R is installed between the left and right side frame members 2 so that its position can be changed in the vertical direction. The lumbar support R is located behind the tension member P and is capable of supporting the lower back of a seated person.

[0053] The lumbar support R comprises a component attached to the backrest E, namely, a lumbar base RB, which is a single component that is spanned between the left and right side frame members 2 of the backrest E so that its position can be changed in the vertical direction, and a pair of left and right lumbar pads RP that are supported on the lumbar base RB so that their position can be changed in the horizontal direction.

[0054] The lumbar support R comprises a lumbar base RB, which is a first part having a through hole r211 elongated in a predetermined left-right direction, and a lumbar pad RP, which is a second part that can adopt a first position, a preparatory position (J), and a second position, a mounted position (S), which is different from the preparatory position (J), and which is maintained mounted to the lumbar base RB in the mounted position (S).

[0055] The wearing position (S) is a position in which the lumbar pad RP is properly fitted to the lumbar base RB. As will be described in detail later, only in the wearing position (S) can the lumbar pad RP be slid smoothly left and right relative to the lumbar base RB by the user applying left and right operating force to the operating body r4. The wearing position (S) is rotated about the axis of the connecting shaft r5 at an angle of approximately 90° from the preparation position (J).

[0056] <Lumber base RB> The lumbar base RB includes left and right held portions r1 disposed at both left and right ends and held by the left and right side frame members 2, and a base body r2 disposed between the left and right held portions r1.

[0057] The lumbar base RB is an integrally molded product made of synthetic resin. That is, the left and right retained portions r1 and the base main body r2 are integrally formed of synthetic resin.

[0058] [Left and right holding parts] The left and right held portions r1 are attached to the left and right side frame members 2 in the vicinity of the bent portions 23 so as to be detachable and slidable in the up and down direction.

[0059] The left and right held portions r1 are held to the lumbar support holding portion N without using fasteners such as screws. The user flexes and deforms the base main body r2 to align the left and right holding portions r1 with the lumbar support holding portion N in the left-right direction. Then, the user simply moves the left and right holding portions r1 backward and brings them closer to the lumbar support holding portion N, so that they are attached to the left and right side frame members 2 in a state that makes them difficult to come off.

[0060] The left and right retained portions r1 are equipped with rail engagement portions r11 that engage with the rail portions n1 provided on the left and right side frame members 2 from the front, engagement claws r12 that act as forward movement restriction portions that engage with groove portions n2 provided on the left and right side frame members 2, and a pair of upper and lower guide protrusions r13 that engage with guide grooves n3 provided on the left and right side frame members 2.

[0061] The rail engaging portion r11 has a generally U-shaped portion that covers the front and both left and right sides of the rail portion n1. More specifically, the rail engaging portion r11 includes a front wall r111 that serves as a rearward movement restricting portion disposed in front of the rail portion n1, an outward extending wall r112 that serves as an inward movement restricting portion extending rearward from the outer edge of the front wall r111, and an inward extending wall r113 that serves as an outward movement restricting portion extending rearward from the inner edge of the front wall r111.

[0062] The front wall r111 of the rail engaging portion r11 covers the forward surface n11 of the rail portion n1. The outward extending wall r112 of the rail engaging portion r11 covers the outward surface n12 of the rail portion n1. The inward extending wall r113 of the rail engaging portion r11 covers the inward surface n13 of the rail portion n1.

[0063] The vertical dimension of the outward extending wall r112 is set shorter than the vertical dimension of the front wall r111. The inner extending wall r113 forms a base for supporting the engaging claws r12 and extends further rearward from the front wall r111 than the outward extending wall r112.

[0064] The engaging claw r12 has a forward surface r121 that is a forward portion that can engage with the rearward surface n21 that is the rearward portion of the groove portion n2. The engaging claw r12 protrudes outward from the outer surface of the inner extending wall r113 that constitutes the rail engaging portion r11.

[0065] The engaging claw r12 is configured to be able to temporarily change its position when attaching or detaching the lumbar support R to or from the backrest E. Only the rear end r122, which is the base end, of the engaging claw r12 is connected to the inner extending wall r113. In other words, the engaging claw r12 is cantilevered relative to the inner extending wall r113 so that temporary position changes can be easily achieved through elastic deformation.

[0066] On the outer side between the rear end portion r122 and the front surface r121 of the engaging claw r12, a pressed inclined surface r123 is provided which is pressed against the rail portion n1 when the lumbar support R is attached to the backrest E.

[0067] The lumbar support R is attached to the backrest E by moving the left and right held portions r1 rearward toward the lumbar support holding portions N of the left and right side frame members 2.

[0068] As the engaging claw r12 moves rearward, the pressed inclined surfaces r123 provided on the engaging claw r12 are pressed by the rail portions n1 provided on the left and right side frame members 2. The engaging claw r12, with the pressed inclined surfaces r123 pressed against it, temporarily changes its position due to elastic deformation of the member, so the left and right held portions r1 are allowed to move rearward until they reach the predetermined mounting positions.

[0069] Thereafter, when the engaging claw r12 reaches the groove portion n2, it is released from engagement with the rail portion n1 and returns to its original position. The forward surface r121 of the engaging claw r12 that has returned to its original position faces the rearward surface n21 of the groove portion n2.

[0070] When an external force acts on the lumbar support R in a direction from rear to front, the forward surfaces r121 of the engaging claws r12 and the rearward surfaces n21 of the left and right side frame members 2 engage with each other, making it difficult for the left and right held portions r1 to move forward. Therefore, after the left and right held portions r1 are properly held by the lumbar support holding portions N, they are suitably prevented from coming off the lumbar support holding portions N.

[0071] Furthermore, if the left and right retained portions r1 are to be actively removed from the lumbar support retaining portion N, a tool or the like can be used to press the pressed inclined surface r123 of the engaging claw r12 while releasing it from engagement with the groove portion n2.

[0072] The guide protrusions r13 are provided on the inner extending wall r113 of the rail engaging portion r11 so as to protrude outward. The guide protrusions r13 are arranged in pairs on the upper and lower parts of the inner extending wall r113. The guide protrusions r13 have rounded tips. The guide protrusions r13 constitute a movement range restriction mechanism Q that restricts the vertical movement range of the lumbar support R relative to the backrest E.

[0073] In other words, a movement range restriction mechanism Q is provided between the backrest E and the lumbar support R to restrict the movement range of the lumbar support R relative to the backrest E in the up and down direction.

[0074] [Base body r2] The base body r2 is disposed between the left and right held portions r1 and has a generally horizontally elongated rectangular shape in a front view. The left and right ends of the base body r2 are integrally connected to the left and right held portions r1. The base body r2 has a curved shape that convexly curves toward the rear.

[0075] The base body r2 has a plate-like portion r21 that is in an upright position and has a horizontally elongated rectangular shape that is arranged in the center in the vertical direction, and a peripheral portion r22 that surrounds the upper, lower, left, and right peripheral portions of the plate-like portion r21 and has a concave shape that protrudes toward the rear.

[0076] The plate-like portion r21 is a flat, upright plate with no protruding portions such as ribs. The plate-like portion r21 is more easily deformed in the thickness direction than the peripheral portion r22. The plate-like portion r21 is configured to be temporarily elastically deformable when the left and right lumbar pads RP are attached and detached.

[0077] As will be described in detail later, the lumbar pad RP is allowed to change its position from the ready position (J) to the attached position (S) by temporary elastic deformation of the plate-like portion r21 provided on the base body r2 of the lumbar base RB. The plate-like portion r21 is pressed by the connecting shaft portion r5 and can temporarily elastically deform in the thickness direction at least when the lumbar pad RP rotates from the ready position (J) to the attached position (S).

[0078] The plate-like portion r21 has left and right through-holes r211 formed in the vertical center thereof, which penetrate in the front-rear direction and extend in the left-right direction. The left and right through-holes r211 are elongated in the left-right direction, penetrate in the front-rear direction, and have a substantially constant vertical width dimension w1. The left and right through-holes r211 are provided corresponding to the left and right lumbar pads RP. The left through-hole r211 and the right through-hole r211 are formed spaced apart on the left and right sides of the plate-like portion r21. In other words, a non-perforated portion is provided between the left through-hole r211 and the right through-hole r211 in the plate-like portion r21. The left and right through-holes r211 define the range of left-right movement of the left and right lumbar pads RP in the wearing position (S).

[0079] The peripheral portion r22 has recesses hk that can function as ribs over its entire area. Due to the presence of the recesses hk, the peripheral portion r22 is less susceptible to bending deformation in the thickness direction than the plate-like portion r21.

[0080] The peripheral portion r22 has an upper peripheral portion forming portion r221 located above the plate-shaped portion r21, a lower peripheral portion forming portion r222 located below the plate-shaped portion r21, and left and right peripheral portion forming portions r223 located on the left and right sides of the plate-shaped portion r21.

[0081] In this embodiment, in order to stabilize the mounting position S of the lumbar pad RP, i.e., to prevent the lumbar pad RP in the mounting position (S) from rotating toward the preparation position (J), the protruding ends t1 of the upper and lower positioning protrusions r33 provided on the lumbar pad RP are configured to contact the upper peripheral portion forming portion r221 and the lower peripheral portion forming portion r222.

[0082] <How to attach the lumber base RB to the left and right side frame materials 2> An example of a method for attaching the lumber base RB to the left and right side frame members 2 will be described below.

[0083] The lumbar base RB can be attached to the left and right side frame members 2 and can also be detached from the left and right side frame members 2 without using fasteners such as screws for the backrest E.

[0084] Even when the lumbar pad RP is not attached to the lumbar base RB, the lumbar base RB can be attached to the left and right side frame members 2.

[0085] Furthermore, even when the lumbar pad RP is attached to the lumbar base RB, the incoming lumbar base RB can be attached to the left and right side frame members 2.

[0086] First, the left and right held portions r1 provided on the left and right sides of the lumbar base RB are positioned in front of the lumbar support holding portions N of the left and right side frame members 2. A tension member P is pre-tensioned between the left and right side frame members 2 that make up the backrest E.

[0087] Therefore, when positioning the left and right retained portions r1 in front of the lumbar support retaining portion N, the lumbar base RB is passed through the upper cavity sa formed by the upper frame-shaped portion wa from the rear, and the left and right retained portions r1 are positioned in front of the lumbar support retaining portion N while the lumbar base RB temporarily presses the tension member P forward.

[0088] The position of the lumbar support holding portion N is gradually inclined upward toward the center in the left-right direction of the backrest E. In other words, the left lumbar support N and the right lumbar support N, which extend in the vertical direction, are not always spaced apart by the same distance in the vertical direction.

[0089] Therefore, when engaging the left and right retained portions r1 with the lumbar support retaining portion N, the base body r2 of the lumbar base RB is elastically deformed (deformed so that the degree of curvature of the base body r2 becomes smaller, or deformed so that the degree of curvature of the base body r2 becomes larger), thereby fine-tuning the left and right positions of the left and right retained portions r1 to match the positions of the lumbar support retaining portion N.

[0090] Next, the left and right held portions r1 are moved while being pressed backward, thereby engaging the rail engaging portion r11, engaging claw r12, and guide protrusion r13 with the rail portion n1, groove portion n2, and guide groove n3 of the left and right side frame members 2. As described above in detail, when the left and right held portions r1 move backward, the engaging claw r12 temporarily changes its position to one in which it is retracted from the rail portion n1, and then returns to its original position and is positioned within the groove portion n2.

[0091] <Left and right lumbar pads RP> Multiple lumbar pads RP, i.e., left and right (two) lumbar pads RP, are arranged in pairs on the left and right of the lumbar base RB. As shown in Figures 33 and 34, the left and right lumbar pads RP are attached so that they can slide left and right relative to the lumbar base RB. The left lumbar pad RP and the right lumbar pad RP have the same structure. The left lumbar pad RP and the right lumbar pad RP can move left and right independently of each other relative to the lumbar base RB.

[0092] In the present specification, the up and down and left and right of the left and right lumbar pads RP will be described based on the wearing position S, which is the second position in which the longitudinal direction is the up and down direction, unless otherwise specified.

[0093] The left and right lumbar pads RP are provided with a pad main body r3 which is an impassable part arranged between the tension member P and the lumbar base RB and which can press the tension member P from the rear, an operating body r4 which is a passable part located on the rear side of the lumbar base RB and can be grasped by the user, and a connecting shaft part r5 which is interposed between the pad main body r3 and the operating body r4 and engages with the left and right through holes r211.

[0094] The pad body r3 has a vertically elongated rectangular shape with four rounded corners when viewed from the front. The pad body r3 constitutes an impassable portion that cannot pass through the through-hole r211. The vertical dimension w2 of the pad body r3 is set to be approximately the same as the vertical dimension w3 of the base body r2 of the lumbar base RB.

[0095] The pad main body r3 includes a pad base r31 in the shape of a vertically elongated rectangular plate, flanges r32 extending rearward from the upper and lower ends of the pad base r31 in a flange-like manner, upper and lower positioning protrusions r33 protruding rearward from the vertical center of each of the upper and lower halves of the pad main body r3, with their protruding ends t1 being able to abut the forward surface of the base main body r2 of the lumbar base RB, a vertical reinforcing rib r34 protruding rearward from the left-right center of the pad main body r3 and extending in the vertical direction to connect the upper and lower positioning protrusions r33 and the connecting shaft r5, and a horizontal reinforcing rib r35 protruding rearward from the vertical center of the pad main body r3 and connected to the connecting shaft r5.

[0096] The operating body r4 is shaped so that the user can hold it with his or her fingers in order to slide the lumbar pad RP in the left-right direction relative to the lumbar base RB.

[0097] The operating body r4 is shaped like a block extending in the vertical direction as a whole. The operating body r4 constitutes a passable portion that can pass through while widening the through-hole r211 provided in the lumbar base RB only when the preparatory posture (J) is adopted. The vertical dimension w4 of the operating body r4, which is the longitudinal direction, is set shorter than the vertical dimension w2 of the pad main body r3, which is the longitudinal direction. The vertical dimension w4 of the operating body r4, which is the longitudinal direction, is set shorter than the longitudinal dimensions of the left and right through-holes r211 provided in the plate-like portion r21.

[0098] The width dimension (short-side dimension) w4 of the rear end, i.e., the tip end t2, of the operating body r4 is set shorter than the width dimension (short-side dimension) w5 of the base end t3, which is the front end, i.e., the connection part with the connecting shaft portion r5 of the operating body r4.

[0099] In other words, the width of the operating body r4 is set so as to gradually increase from the distal end t2 toward the proximal end t3 (so as to gradually increase in width from the distal end t2 toward the proximal end t3). The width w4 of the distal end t2 of the operating body r4 is set so as to substantially match the vertical width w1 of the through-hole r211 provided in the plate-like portion r21 of the base main body r2.

[0100] The connecting shaft r5 has a rectangular columnar shape and extends in the front-rear direction so as to connect the vertical and horizontal centers of the pad main body r3 and the vertical center of the operating body r4. The connecting shaft r5 connects the pad main body r3 and the operating body r4, and a portion of the connecting shaft r5 is disposed within the through-hole r211.

[0101] The connecting shaft portion r5 is a generally rectangular pillar-shaped portion having a vertical dimension w7 set to a value that substantially matches the vertical width dimension w1, which is the short dimension of the through-hole r211. The vertical dimension w7 of the connecting shaft portion r5 in the mounting position S is set to a dimension that substantially matches the vertical width dimension w1 of the through-hole r211 provided in the plate-like portion r21 of the base main body r2.

[0102] On the other hand, the left-right dimension w8 of the connecting shaft r5 in the mounting posture S is set to be longer than the up-down dimension w7 of the connecting shaft r5 in the mounting posture S. The width dimension w5 of the base end t3 of the operating body r4 and the left-right dimension w8 of the connecting shaft r5 are set to be approximately the same dimension.

[0103] <How to attach the lumbar pad RP to the lumbar base RB> An example of a method for attaching the left and right lumbar pads RP to the lumbar base RB will be described below. The left and right lumbar pads RP can be attached to the lumbar base RB when it is not attached to the backrest E, and can also be attached to the lumbar base RB when it is attached to the backrest E.

[0104] The left and right lumbar pads RP can take two positions: a preparatory position (J) in which they are attached to the lumbar base RB, i.e., a position in which the operating body r4 can be inserted and removed from the through-hole r211 of the lumbar base RB, and an attached position (S) in which they are attached to the lumbar base RB, which is a position different from the preparatory position (J).

[0105] The wearing position (S) is rotated about the axis of the connecting shaft r5 at an angle of approximately 90° from the preparation position (J). The wearing position (S) is the position of the lumbar pad RP in which the operating body r4 cannot be inserted or removed from the through-hole r211 of the lumbar base RB. In this embodiment, in the preparation position (J), the pad main body r3 and the operating body r4 are horizontally elongated, and in the wearing position (S), the pad main body r3 and the operating body r4 are vertically elongated.

[0106] First, as shown in FIG. 24, the lumbar pad RP is placed in the preparation position (J) and positioned in front of the lumbar base RB.

[0107] Next, as shown in Fig. 25, the tip t2 of the operating body r4 of the lumbar pad RP is inserted from the front to the rear into the through-hole r211 while the operating body r4 is in the preparatory position (J). The operating body r4 can pass through the through-hole r211 from the front to the rear only when the operating body r4 is in the preparatory position (J).

[0108] The vertical width dimension w1 of the through hole r211 is approximately the same as the width dimension w5 of the tip end t2 of the operating body r4, but is shorter than the width dimension w6 of the base end t3 and the width dimension w8 of the connecting shaft portion r5.

[0109] Therefore, when the operating body r4 and connecting shaft portion r5 of the lumbar pad RP in the preparatory position (J) pass through the through hole r211, the plate-shaped portion r21 in which the through hole r211 is provided is elastically deformed so as to be pushed open by the operating body r4 and connecting shaft portion r5.

[0110] In other words, when the operating body r4 and the connecting shaft portion r5 in the preparatory position (J) are inserted into the through-hole r211 from the front to the rear, the plate-like portion r21 is pressed by the operating body r4 and the connecting shaft portion r5 and can temporarily elastically deform to allow them to pass through.

[0111] 26 and 27, the worker grasps the operating body r4 or the pad main body r3 and rotates them by approximately 90 degrees to change the position of the lumbar pad RP from the preparation position (J) to the wearing position (S). That is, after passing the operating body r4 through the through-hole r211 and positioning the connecting shaft r5 within the through-hole r211, the worker rotates the lumbar pad RP around the axis of the connecting shaft r5 to change the position from the preparation position (J) to the wearing position (S).

[0112] In more detail, the worker passes the lumbar pad RP, which is in the preparation position (J), through the through hole r211 in the order of the operating body r4 and the connecting shaft portion r5, and then rotates the lumbar pad RP to the right or left around the axis of the connecting shaft portion r5 to change its position from the preparation position (J) to the wearing position (S).

[0113] When the connecting shaft r5 rotates approximately 90° from the ready position (J) to the attached position (S) within the through-hole r211, the plate-like portion r21 is temporarily pushed outward by the diagonal corners of the connecting shaft r5, widening the through-hole r211 to the maximum. In this way, the temporary elastic deformation of the plate-like portion r21 allows the lumbar pad RP to change position from the ready position (J) to the attached position (S).

[0114] When the lumbar pad RP transitions from the preparation position (J) to the mounting position (S), the vertical dimension w7 of the connecting shaft portion r5 in the mounting position (S) approximately matches the vertical width dimension w1 of the through hole r211, and the plate-shaped portion r21 of the base body r2 returns from its expanded state to its original relatively flat state.

[0115] In this embodiment, a return-back prevention means G is provided between the lumbar base RB and the lumbar pad RP to prevent the lumbar pad RP from returning from the mounted position (S) to the ready position (J). The return-back prevention means G is provided on the lumbar pad RP side and is composed of a connecting shaft portion r5 whose up-down dimension w7 in the mounted position (S) is set shorter than its left-right dimension w8, and a through-hole r211 provided on the lumbar base RB side, extending in the left-right direction, and whose up-down width dimension w1 is set to be approximately the same as the up-down dimension w7 of the connecting shaft portion r5.

[0116] After the above steps, the lumbar pad RP is attached to the lumbar base RB. The left and right lumbar pads RP attached to the lumbar base RB can be moved left and right relative to the lumbar base RB at the user's discretion by gripping the operating body r4 and operating it left and right.

[0117] The lumbar pad RP can be removed from the lumbar base RB by reversing the above-described procedure.

[0118] The above-described embodiment can provide a chair with excellent design freedom, allowing at least the second part, the lumbar pad RP, to be easily attached to the first part, the lumbar base RB.

[0119] Furthermore, with the above-described embodiment, at least the lumbar support R can be attached and detached from the backrest E without attaching or detaching a fastening device, and a chair can be provided that has a configuration that makes it difficult for the lumbar support S to come off the backrest E even when it is subjected to an external force from behind.

[0120] Furthermore, the above-described embodiment makes it possible to provide a chair having a lumbar support R that can flexibly adjust the strength of support for the occupant's lower back to suit the occupant's physique and preferences.

[0121] As described above, the chair of this embodiment has a backrest E with a mesh-like tension member P stretched between the left and right side frame members 2, and a lumbar support R attached to the backrest E that can support the lumbar region of the seated person via the tension member E.

[0122] The lumbar support R comprises a lumbar base RB which is installed between the left and right side frame members 2 so that its position can be changed in the vertical direction, and a lumbar pad RP which is supported on the lumbar base RB so that its position can be changed in the horizontal direction.

[0123] This makes it possible to provide a chair having a configuration that allows the strength of support for the lumbar region of the seated person to be flexibly adjusted to suit the physique and preferences of the seated person.

[0124] That is, the lumbar pad RP is supported so that its position can be changed in the left-right direction relative to the lumbar base RB. Moreover, the lumbar base RB is installed between the left and right side frame members 2 so that its position can be changed in the up-down direction.

[0125] Therefore, by combining changes in the vertical position of the lumbar base RB and changes in the horizontal position of the lumbar pad RP, it is possible to relatively easily realize a variety of ways of supporting the lumbar region of the seated person.

[0126] A pair of lumbar pads RP are arranged on the left and right sides of the lumbar base RB.

[0127] Therefore, by moving the left and right lumbar pads RP in the left and right directions, various modes of supporting the lumbar region of the seated person can be adopted.

[0128] The left and right side frame materials 2 are roughly "L" shaped when viewed from the side and have a bent portion 23 in the middle in the vertical direction, and the left and right ends of the lumbar base RB are attached near the bent portion 23.

[0129] Therefore, the lumbar support R can be disposed in the forward protruding portion of the backrest E, which is suitable for supporting the lumbar region of the seated person.

[0130] A through hole r211 is provided in the vertical center of the lumbar base RB, penetrating in the front-to-back direction and extending in the left-to-right direction.The lumbar pad RP comprises a pad main body r3 arranged between the tension member P and the lumbar base RB and capable of pressing the tension member P from the rear, an operating body r4 located on the back side of the lumbar base RB and capable of being held by the user, and a connecting shaft portion r5 interposed between the pad main body r3 and the operating body r4 and engaging with the through hole r211.

[0131] Therefore, the lumbar pad RB has a suitable configuration in which the pad main body r3 can press against the lumbar region of the seated person via the upholstery member P, and the connecting shaft r5 and the operating body r4 can be easily operated to move the pad RB left and right along the through-hole r211. In other words, since the operating body r4 is located on the back side of the lumbar base RB, the user can easily access the operating body r4 from the back side of the backrest E.

[0132] The lumbar pad RP can take a preparatory position (J), which is the position when it is attached (attached) to the lumbar base RB, and an attached position (S), which is a position different from the preparatory position (J) and is attached to the lumbar base RB.

[0133] The operating body r4 can pass through the through hole r211 from front to rear only when it is in the preparatory position (J). After the operating body r4 has passed through the through hole r211, the lumbar pad RP is rotated around the axis of the connecting shaft portion r5 to change its position from the preparatory position (J) to the attached position (S), thereby attaching the lumbar pad RP to the lumbar base RB.

[0134] Therefore, the lumbar pad RP can be attached relatively easily to the lumbar base RB having the through hole r211 by rotating it around the axis of the connecting shaft portion r5.

[0135] The mounting posture (S) is obtained by rotating the connecting shaft portion r5 about the axis at an angle of approximately 90° with respect to the preparation posture (J).

[0136] Therefore, the lumbar pad RP can be attached to the lumbar base RB by simply rotating the lumbar pad RP by 90 degrees.

[0137] The vertical dimension w7 of the connecting shaft portion r5 in the mounting position (S) is set to a dimension that substantially matches the vertical width dimension w1 of the through-hole r211.

[0138] Therefore, in the wearing position (S), the lumbar pad RP is suitably engaged with the through hole r211 without impeding its movement in the left and right directions, and rattle of the lumbar pad RP relative to the through hole r211 is suitably suppressed.

[0139] The lumbar base RB has a plate-like portion r21 in which a through hole r211 is formed, and the plate-like portion r21 can be temporarily elastically deformed at least when the lumbar pad RP rotates by being pressed against the connecting shaft portion r5, and the lumbar pad RP is allowed to change its position from the preparation position (J) to the wearing position (S) by the temporary elastic deformation of the plate-like portion r21.

[0140] Therefore, the lumbar pad RP in the wearing position (S) is preferably supported by the lumbar base RB in such a manner that it is difficult for the lumbar pad RP to return to the preparation position (J).

[0141] The present invention is not limited to the above-described embodiment.

[0142] The connection between the lumbar support and the left and right side frame members can take various forms and is not limited to those shown in the above-described embodiment.

[0143] The lumbar pad may be supported on the lumbar base in any manner so long as its position can be changed in the left-right direction. In other words, the manner in which the lumbar pad is supported on the lumbar base can take various forms and is not limited to the embodiment described above.

[0144] For example, the lumbar pad may have portions that can engage the upper and lower edges of the lumbar base.

[0145] The lumbar pad may be a single one, or three or more lumbar pads may be arranged on the lumbar base.

[0146] It goes without saying that the lumbar base and lumbar pad may take on various shapes within the scope of the present invention.

[0147] Furthermore, the specific configuration of each part is not limited to the above embodiment, and various modifications are possible within the scope of the present invention. [Explanation of symbols]

[0148] 2...Left and right side frame members P... tension member E...backrest R...Lumbar support RB...Lumber base RP…Lumbar pad

Claims

1. A chair having a backrest with a mesh-like tension member stretched between left and right side frame members, and a lumbar support attached to the backrest that can support the lumbar region of a seated person via the tension member, The lumbar support includes a lumbar base that is installed between the left and right side frame members so that its position can be changed in the up and down direction, and a lumbar pad that is supported on the lumbar base so that its position can be changed in the left and right direction, A through hole is provided in the vertical center of the lumbar base, the through hole penetrating in the front-rear direction and extending in the left-right direction, The lumbar pad comprises a pad body disposed between the upholstery member and the lumbar base and capable of pressing the upholstery member from the rear side, an operating body located on the rear side of the lumbar base and capable of being held by a user, and a connecting shaft portion interposed between the pad body and the operating body and engaging with the through-hole, The lumbar pad can take a preparatory position, which is a position when the lumbar pad is attached to the lumbar base, and an attached position, which is a position different from the preparatory position and is attached to the lumbar base, the operating body can pass through the through-hole from the front to the rear only when the operating body takes the preparatory posture, After the operating body is passed through the through-hole, the lumbar pad is rotated around the axis of the connecting shaft portion to change its position from the preparation position to the mounting position, whereby the lumbar pad is mounted to the lumbar base, a vertical dimension of the connecting shaft portion in the mounting position is set to a dimension that substantially matches a vertical width dimension of the through hole, The lumbar base has a plate-shaped portion in which the through hole is formed, the plate-like portion is pressed against the connecting shaft portion at least when the lumbar pad rotates, and is thereby temporarily elastically deformed; The lumbar pad is capable of changing its position from the preparation position to the attached position by temporary elastic deformation of the plate-shaped portion.

2. 2. The chair according to claim 1, wherein the lumbar pads are disposed in pairs on the left and right sides of the lumbar base.

3. The left and right side frame members are generally "L" shaped in a side view and have a bent portion in the middle in the up-down direction, 3. The chair according to claim 1, wherein both left and right ends of the lumbar base are attached near the bent portion.

4. 4. The chair according to claim 1, 2 or 3, wherein the mounting position is rotated about the axis of the connecting shaft at an angle of approximately 90 degrees with respect to the preparation position.

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