Chair and its backrest

Abstract

To secure body stability by holding shape retention while securing high cushioning and fitting properties by having a soft-elastomer backboard.SOLUTION: A backboard 2 is provided with high flexibility by having a large number of through holes 21 and is deformable by following up movement of a user. An upper reinforcement member 13 is fastened in an upper end part in the rear face of the backboard 2, and so is a lower reinforcement member 16 in a lower end part in the rear face of the backboard 2. The upper reinforcement member 13 is connected to an upper support 11 of a back frame 3, while the lower reinforcement member 16 is fixed on a lower support 12 of the back frame 3. The upper support 11 is capable of performing horizontal rotation against resilience. The backboard 2 is deformable by following up the movement of a user while retaining the entire shape. Consequently, the chair can secure high fitting and cushioning properties while securing stability of the user's body.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] Chairs come in various forms. The swivel chair commonly used in offices consists of a leg device with casters, a seat, and a backrest as its main components, and optional accessories such as armrests, headrests, and hangers are attached.

[0003] Also, many swivel chairs are equipped with a reclining function that allows the backrest to tilt backward. With such a reclining function, the sitter can relax the body and continue to use it for a long time.

[0004] Important factors for maintaining comfort in a chair are the fit, cushioning, and softness of the backrest. Therefore, the front surface of the backrest is made of a cushioning material or the body is supported by a mesh material. The mesh material also has the advantage of preventing sweating due to its excellent breathability.

[0005] Now, when the sitter leans on the backrest, the center line of the upper body is not always aligned with the center line of the backrest. The sitter may lean with the upper body tilted to the right or left, or twist the body while leaning on the backrest and turn backward. In these cases, the pressing force (body pressure) due to the sitter's leaning acts strongly and is biased towards the left or right side of the backrest.

[0006] And the backrest of a chair basically has a rigidity that hardly deforms under the pressing force of the sitter. However, if the backrest has a rigid structure, a part of the sitter's body will strongly hit a part of the backrest, resulting in a loss of comfort.

[0007] Therefore, a chair has been proposed that allows the backrest to bend and deform (twist) under the pressing force of the seated person, and an example of this is disclosed in Patent Document 1. Patent Document 1 relates to the applicant's previous application, and at the upper end of the back column, a Upper support is attached so as to horizontally pivot against a spring, Upper both left and right ends of the backrest are connected to both left and right ends of the support, and when the user's load acts with a bias to either the left or right, Upper the support horizontally pivots, causing the backrest to twist and deform.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In Patent Document 1, since the backrest bends and deforms (twists) under the pressing force of the seated person, when the upper body is shifted to the right or left and leaned against the backrest, the backrest follows and deforms. Therefore, it is possible to allow the movement of the seated person's body and soften the contact of the backrest with the body. As a result, it can be said that the comfort can be improved.

[0010] Here, in order to enhance the cushioning property and fitness of the backrest, it is beneficial to configure the back plate with a soft material such as an elastomer. However, since a soft material such as an elastomer is weak in strength, simply replacing the backrest of Patent Document 1 with an elastomer may not ensure the shape retention of the backrest.

[0011] The present invention has been made in view of such a situation and aims to preferably develop Patent Document 1.

Means for Solving the Problems

[0012] The invention of the present application includes many components, and typical examples are specified in each claim. Among these, the invention of claim 1 is "a back plate made of a soft material that bends and deforms under the pressing force of the seated person, a back frame to which the back plate is attached, and the back plate includes two upper and lower side portions that are opposite upper and lower side portions, and two left and right side portions that are opposite left and right side portions, the two upper and lower sides The part are holding side portions attached to the back frame, The left and right side parts which are free deformation portions that can extend and deform under the pressing force of the seated person, On the upper side of the back plate, left and right longitudinally extending upper reinforcing members overlap from the rear side, and on the lower side of the back plate, left and right longitudinally extending lower reinforcing members overlap from the rear side. In this basic configuration, The upper reinforcing member is formed in a plate shape and is allowed to bend and deform backward together with the upper side of the back plate, and the upper reinforcing member is attached to the back frame in a state of being supported at both ends. and has the following configuration.

[0013] The invention of claim 2 is based on claim 1 It is juxtaposed with, and in the same basic configuration as Claim 1, 「 the Of the back plate lower side portion and the lower reinforcing member are fixed to the back frame in a state where they do not deform over their entire lengths, the Of the back plate upper side portion and the upper reinforcing member are attached to the back frame in a state of being supported at both ends so that backward bending deformation is allowed." and has the following configuration.

[0014] The invention of claim 3 is, in claim 2, "the back frame has a back support located at the left - right middle portion and an arm portion extending left and right from its upper end, the upper side portion of the back plate is connected to both left and right ends of the arm portion, and the arm portion is attached to the back support in a state where it can pivot horizontally against elasticity." and has the following configuration.

[0015] The invention of claim 4 is an expansion of claim 2 or 3, "Downward protrusions are provided at both left and right ends of the upper reinforcing member, and upward protrusions are provided at both left and right ends of the lower reinforcing member." It has such a configuration.

[0016] The invention of claim 5 Is an independent invention, and in the same basic configuration as Claim 1, "On the back plate, a group of Hole openings that are longitudinally long in the vertical direction and open front and rear are formed in multiple rows and multiple stages in the left - right direction and the vertical direction, and at the upper part of the back plate where the upper reinforcing member overlaps, a concave groove continuous with the Hole is formed, and the back plate is thinner at the location of the concave groove." It has such a configuration.

[0017] Please Claim 6 The invention relates to a chair, and the chair "has a seat on which a seated person sits, legs that support the seat, and a backrest of the chair according to any one of claims 1 to 5 ." And, It is provided with Is .

Effect of the Invention

[0018] In the present invention, even if the back plate is made of a soft material such as an elastomer, the back plate is shaped by the reinforcing member, so that while stabilizing the shape of the back plate, deformation due to the body pressure of the seated person can be tolerated. Therefore, even if a group of punched holes is formed in the back plate, the freedom in design such as the shape and pattern of the punched holes can be improved, and the fit and cushion properties of the back plate can be improved. Each When the configuration of claim 2 is adopted, deformation of the back plate due to the body pressure (pressing force) of a seated person is allowed, so that the back plate can be deformed following the movement of the user's body,

[0019] and the fit and cushion properties can be further improved. Elongation To

[0020] When adopting the configuration of claim 3, while ensuring the shape retention of the backrest, the backrest can be deformed following the twisting of the user's body. That is, while preventing the backrest from being overly deformed by the upper reinforcing member, while moderately holding the body, the backrest can be made to follow the movement of the body. Therefore, the features of Patent Document 1 can be improved and the value of the chair can be enhanced.

[0021] When adopting the configuration of claim 4, the integrality between the upper reinforcing member and the backrest, and the integrality between the lower reinforcing member and the backrest can be improved, and the shape retention function of the backrest can be enhanced.

[0022] When forming a large number of punching holes in the backrest as in claim 5, the backrest can be configured to be moderately deformed. And since a reinforcing member is overlapped and arranged at the upper end portion of the backrest, punching holes cannot be formed in the portion where the reinforcing members overlap, but due to the concave grooves, the group of punching holes appears to extend to the upper end edge of the backrest, so it is possible to prevent a blank portion from appearing at the upper end portion of the backrest and improve the aesthetics.

[0023] Also, in claim 5, since the portion of the concave groove is thin, the upper end portion of the backrest is allowed to bend and deform together with the upper reinforcing member. Therefore, it has excellent cushioning properties.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying out the Invention

[0025] Next, embodiments of the present invention will be described with reference to the drawings. Hereinafter, the terms "front and rear" and "left and right" are used to specify directions, and these directions are specified as the state seen from a person sitting normally. The front view direction is the direction facing the seated person.

[0026] (1) Overview of the Chair First, an overview of the chair will be described. The chair of this embodiment is applied to a swivel chair frequently used in an office or the like. As shown in FIGS. 1 and 2, the chair includes, as main members, a seat 1, a backrest 2, a back frame 3 to which the backrest 2 is attached, and a leg device 4. The backrest 2 is made of a resin-based soft material such as an elastomer. In this embodiment, the backrest 2 is synonymous with the backrest.

[0027] The leg device 4 has a group of branched legs provided with casters (in FIGS. 1(A) and 1(D), only a part of the casters is shown). Also, as shown in FIG. 2, a base body 6 is fixed to a leg support (gas cylinder) 5 arranged at the center, and the back frame 3 is connected to the base body 6 via a joint member 7 so as to be tiltable backward. To describe precisely, a forward-facing portion 3a is integrally provided at the lower end of the back frame 3, the forward-facing portion 3a is fixed to the joint member 7, and the joint member 7 is connected to the base body 6 via a left-right longitudinal support shaft 8 so as to be tiltable backward.

[0028] The support shaft 8 is rotatably held on the base body 6 via a torsion bar as an example of spring means. Therefore, the chair of the present embodiment is a reclining type in which the backrest 2 tilts backward against the elastic means. The seat 1 has a structure in which a cushion material is stacked on an inner shell (not shown) and covered with a skin material, and the inner shell is attached to the outer shell 9 shown in FIG. 1(B). The outer shell 9 is connected to the base body 6 and the joint member 7 so as to be relatively rotatable. Therefore, when the backrest 2 tilts backward, the seat 1 tilts (synchronizes) backward in conjunction with the backrest 2.

[0029] As shown in FIG. 4, the back frame 3 has upper and lower longitudinal back support columns 10 located at the left and right middle portions, left and right longitudinal upper supports 11 horizontally rotatably attached to the upper ends thereof, and left and right lower supports 12 integrally provided at the lower ends of the back support columns 10. The upper support 11 horizontally rotates against a spring built into the back support column 10. The back support column 10 and the upper support 11 are made of synthetic resin, but aluminum die-cast products or sheet metal processed products can also be adopted.

[0030] For example, as shown in FIG. 4, the upper support 11 has a portion facing left and a portion facing right from the axis of the back support column 10, and both are integrally connected. The left and right ends are free ends. The upper support 11 is in a bowed shape in plan view so as to be concave forward (bulging backward), and the left and right end portions of the backrest 2 are connected to the left and right end portions thereof. Therefore, a large space is left between the upper support 11 and the backrest 2. Due to the existence of this space, the upper end portion of the backrest 2 is allowed to extend and deform (recess and deform) backward by the pressing force (body pressure) of the seated person.

[0031] On the rear surface of the upper end portion of the backrest 2, there is a left and right longitudinal Plate-shaped upper reinforcing member 13 fixed by insert molding or two-color molding By integral molding like method, and the left and right end portions of the upper reinforcing member 13 are connected to the upper support 11 via clip bodies 14. Upper boss portions 15 overlapping the upper support 11 project rearward at the left and right end portions of the upper reinforcing member 13.

[0032] On the other hand, as shown clearly in FIG. 4, the lower support 12 is curved such that the upper and lower surfaces are higher toward the tip in a rear view, and the lower surface (i.e., the lower surface of the back frame 3) formed by the lower surfaces of the left and right lower supports 12 and the lower surface of the back support 10 etc. is also a downwardly bulging curved surface. Therefore, the back frame 3 is in a shape similar to an anchor as a whole.

[0033] As shown in FIG. 1(D) for example, in a plan view, the lower support 12 extends forward in a state of embracing the rear part of the seat, and the armrest device 6 is attached to the tip thereof. The lower support 12 is narrower toward the tip in both plan view and rear view.

[0034] Left and right longitudinal lower reinforcing members 16 are integrally fixed to the rear surface of the lower end of the back plate 2 by an insert molding method or a two-color molding method, and the left and right ends of the lower reinforcing member 16 are fixed to the tips of the lower supports 12 with screws 17 (see FIGS. 3 and 5). Lower boss portions 18 that fit into the lower supports 12 project rearward from the left and right ends of the lower reinforcing member 16. The upper and lower reinforcing members 13 and 16 are made of synthetic resin such as polypropylene, nylon resin, and polycarbonate.

[0035] As can be understood from FIG. 4, the back surface of the back frame 3 is covered with a center cover 19 and side covers 20. That is, the center cover 19 covers the whole of the back support 10 and a part of the lower support 12, and the side cover 20 covers the rear surface of the front half of the lower support 12. When the side cover 20 is removed, the armrest device can be attached to the lower support 12.

[0036] The back plate 2 has a strength that allows it to easily flex and deform under the pressing force exerted when the seated person leans on it. And in order to facilitate its deformation, rows of perforations (Slit) 21 are formed in multiple stages. The group of holes 21 located at the uppermost stage penetrate front and back below the upper reinforcing member 13. On the front surface of the part of the back plate 2 where the upper reinforcing member 13 overlaps, a group of concave grooves 21a communicating with the holes 21 and extending to the vicinity of the upper end of the back plate 2 are formed. Therefore, it presents an appearance as if the holes 21 are formed up to near the upper end of the back plate 2. The back plate 2 is thinner at the location of the concave grooves 21a. The lower end of the backrest 2 is immovably fixed to the lower support 12, while the upper end of the backrest 2 is attached to the left and right ends of the horizontally rotatable upper support 11. Therefore, when a person sitting on the chair twists their upper body, the lower support 12 rotates horizontally, causing the backrest 2 to elastically deform, such as bending or concave backward, following the torsion of the body. Therefore, the upper reinforcement member 13 can be elastically deformed (bent deformation) by the pressing force of the user.

[0037] In addition, the lower support 12 protrudes upward higher than the seat 1. Therefore, as shown in FIGS. 1(A) and 1(B), the left and right raised portions 1a are formed at the rear of the seat 1. Therefore, the holding property of the seat 1 for the user's waist (buttocks) is enhanced.

[0038] (2). Fixing structure between the backrest and the lower support As shown in FIG. 5(A), the lower reinforcement member 16 has a shell shape that curves along the lower support 12 and opens forward, and a number of reinforcing ribs are provided inside. Therefore, the lower support 12 has a rigid structure that does not deform even when the pressing force of the seated person acts thereon. Therefore, the lower edge of the backrest 2 is firmly fixed to the lower support 12 via the lower reinforcement member 16.

[0039] Truncated pyramidal lower boss portions 18 are provided at the left and right ends of the lower reinforcement member 16. On the other hand, recesses 23 into which the lower boss portions 18 are fitted are provided at the tip ends of the left and right lower supports 12, and screws 17 inserted from the outside into the recesses 23 are screwed into the lower boss portions 18 of the lower reinforcement member 16. Although not shown, nuts 23a into which the screws 17 are screwed are attached to the lower boss portions 18 of the lower reinforcement member 16.

[0040] Although not shown, a plurality of positioning protrusions are provided on the left and right of the lower reinforcement member 16, and positioning holes into which the positioning protrusions are fitted are provided in the lower support 12. By fitting the positioning protrusions and the positioning holes, even with fixation by two screws 17 on the left and right, the lower reinforcement member 18 can be firmly fixed to the lower support 12.

[0041] As shown in FIG. 4(A) and FIG. 5, while the left and right end portions of the lower reinforcing member 16 are integrally formed with spatula-shaped upward protrusions 24, recesses 25 into which the upward protrusions 24 of the lower reinforcing member 16 are fitted are provided at the left and right end portions of the back plate 2. By pulling The lower reinforcing member 16 is integrally formed with the back plate 2 by an insert molding method or a two-color molding method. However, since the adhesive area is increased due to the presence of the upward protrusions 24, the lower reinforcing member 16 can be firmly fixed to the back plate 2.

[0042] (3). Fixing structure between the back plate and the upper support As shown in FIGS. 6(A) and 6(C), the upper boss portion 15 protrudes rearward and downward of the upper reinforcing member 13. Therefore, the upper boss portion 15 constitutes the downward protrusion described in the claims. And the rear surface of the upper boss portion 15 overlaps with the front surface of the upper support 11. On the other hand, downward protrusions 26 are provided at the left and right ends of the upper support 11 so as to overlap with the upper boss portion 15. Since the upper boss portion 15 has a vertical width more than twice that of the upper reinforcing member 13 and has a wide area, it is firmly fixed to the back plate 2.

[0043] And while a downward hook-shaped engaging claw 27 is formed on the rear surface of the upper boss portion 15, bag-shaped portions 28 into which the engaging claws 27 are fitted are formed at the left and right end portions of the upper support 11, and engaging holes 29 into which the engaging claws 27 are inserted from above are formed at the bottom 28a of the bag-shaped portions 28, thereby holding the upper boss portion 15 and the upper support 11 so as not to be separated from each other in the front-rear and left-right directions.

[0044] Furthermore, a cutout groove 31 with a forward opening is formed in the partition wall 30 constituting the bag-shaped portion 28, and the claw portion 14a of the clip body 14 is inserted into the cutout groove 31 from the inner side in the left-right direction. The clip body 14 includes a base portion 14b located inside the partition wall 30, and the claw portion 14a can be inserted into the cutout groove 31 by pushing the base portion 14b outward in the left-right direction with a fingertip.

[0045] The claw portion 14a of the clip body 14 is bent into a horizontal U shape. Once elastically deformed, it enters the cutout groove 31. When it fully enters the cutout groove 31, the U-shaped tip surface 14c disengages from the cutout groove 31 and contacts the outer surface of the partition wall 30. As a result, the clip body 14 is in a state where it cannot be removed from the cutout groove 31. Becomes 。

[0046] And in the state where the clip body 14 is attached to the cutout groove 31, the claw portion 14a of the clip body 14 overlaps the upper surface of the engaging claw 27 of the upper reinforcing member 13. Therefore, the engaging claw 27 of the upper reinforcing member 13 is held immovable upward by the claw portion 14a of the clip body 14. Also, the front end surface of the partition wall 30 in the upper support 11 overlaps the upper boss portion 15 of the upper reinforcing member 13, and since the cutout groove 31 is blocked by the upper boss portion 15 of the upper reinforcing member 13, the forward movement of the clip body 14 is blocked by the upper boss portion 15 of the upper reinforcing member 13.

[0047] As can be understood from FIG. 6(B), a stopper 32 that abuts or closely contacts the claw portion 14a of the clip body 14 from the front is provided on the upper boss portion 15 of the upper reinforcing member 13. As can be understood from FIG. 6, the upper support 11 has a gutter-like structure that opens forward, and reinforcing ribs are provided inside. As shown in FIG. 6(C), a center boss portion 33 that is horizontally rotatably attached to the back support 10 is formed at the left and right middle portion of the upper support 11.

[0048] (4). Summary In this embodiment, since the lower end of the back plate 2 is fixed to the lower support 12 via the lower reinforcing member 16 having a rigid structure, the lower end of the back plate 2 does not elastically deform even when the body pressure of the user acts thereon. Therefore, the user's waist (hip) is always firmly supported, and the waist is always maintained in a stable state.

[0049] On the other hand, the backrest 2 is made of an elastomer and is highly flexible, bending and deforming following the pressing force of the user. However, since the upper reinforcement member 13 with high rigidity is fixed to the upper end, while maintaining the form as the backrest 2, it extends backward or twists and deforms in a plan view. Therefore, while stably holding the user's body, it deforms following the movement thereof, ensuring high fitness and cushioning properties.

[0050] Furthermore, in this embodiment, since the upper reinforcement member 13 also bends and deforms to some extent, it can bend and deform due to the pressing force of the user to ensure high cushioning properties. Also, when a large number of through holes 21 are formed in the backrest 2 as in this embodiment, the flexibility of the backrest 2 can be enhanced to further improve the fitness and cushioning properties. However, by variously selecting the shape and arrangement pattern of the through holes 21, etc., the range of design can be expanded while ensuring the fitness and cushioning properties.

[0051] As described above, the embodiments of the present invention have been explained. However, the present invention can be embodied in various other ways. For example, when the upper support rotates horizontally as in the embodiment, the upper reinforcement member can also be configured with a rigid structure. Of.

[0052] The upper and lower reinforcement members do not necessarily have to be integrally formed with the backrest by insert molding or the like, and may be fixed to the backrest by fasteners such as screws. Also, The upper reinforcement member can also be fixed to the back frame with a fastener such as a screw.

Industrial Applicability

[0053] The present invention can be embodied in a chair. Therefore, it can be used industrially.

Explanation of Reference Numerals

[0054] 2 Backrest 3 Back frame 10 Back column 11 Upper support 12 Lower support 13 Upper reinforcement member 14 Clip body Upper boss part Lower reinforcement member Lower boss part 21 Hole 21a Concave groove Upward protruding part Engaging claw Engaging hole Partition wall Slit hole

Claims

1. A backrest made of a soft material that bends and deforms under the pressing force of a seated person, a back frame to which the backrest is attached, and is provided with, The backrest includes upper and lower two side portions that are upper and lower side portions facing each other, and left and right two side portions that are left and right side portions facing each other, The upper and lower two side portions are holding side portions attached to the back frame, and the left and right two side portions are free deformation portions that can extend and deform under the pressing force of a seated person, An upper reinforcing member extending longitudinally left and right overlaps from the rear side on the upper side portion of the backrest, and a lower reinforcing member extending longitudinally left and right overlaps from the rear side on the lower side portion of the backrest. It is a backrest of a chair, The upper reinforcing member is formed in a plate shape and is allowed to bend and deform backward together with the upper side portion of the backrest, and the upper reinforcing member is attached to the back frame in a state of being supported at both ends. Backrest of a chair.

2. A backrest made of a soft material that bends and deforms under the pressing force of a seated person, a back frame to which the backrest is attached, and is provided with, The backrest includes upper and lower two side portions that are upper and lower side portions facing each other, and left and right two side portions that are left and right side portions facing each other, The upper and lower two side portions are holding side portions attached to the back frame, and the left and right two side portions are free deformation portions that can extend and deform under the pressing force of a seated person, An upper reinforcing member extending longitudinally left and right overlaps from the rear side on the upper side portion of the backrest, and a lower reinforcing member extending longitudinally left and right overlaps from the rear side on the lower side portion of the backrest. It is a backrest of a chair, The lower side portion of the backrest and the lower reinforcing member are fixed to the back frame in a state where they do not deform over their entire length, The upper side portion of the backrest and the upper reinforcing member are attached to the back frame in a state of being supported at both ends so that backward bending deformation is allowed. Backrest of a chair.

3. The back frame has a back support located at the left and right middle parts, and arm parts projecting left and right from the upper end thereof. The upper side parts of the back plate are connected to both left and right ends of the arm parts. The arm parts are attached to the back support in a state where they can horizontally pivot against elasticity. The backrest of the chair according to claim 2.

4. Downward protruding parts are provided at both left and right ends of the upper reinforcing member. Upward protruding parts are provided at both left and right ends of the lower reinforcing member. The backrest of the chair according to claim 2 or 3.

5. A back plate made of a soft material that flexes and deforms under the pressing force of a seated person, A back frame to which the back plate is attached, comprising: The back plate includes upper and lower two side parts that are opposite upper and lower side parts, and left and right two side parts that are opposite left and right side parts. The upper and lower two side parts are holding side parts attached to the back frame, and the left and right two side parts are free deformation parts that can extend and deform under the pressing force of a seated person. On the upper side part of the back plate, left and right longitudinal upper reinforcing members overlap from the rear side, and on the lower side part of the back plate, left and right longitudinal lower reinforcing members overlap from the rear side. The backrest of the chair is such that A group of punching holes that are longitudinally up and down and open front and rear are formed in multiple rows and multiple stages in the left - right direction and the up - down direction on the back plate. On the upper part of the back plate where the upper reinforcing member overlaps, a concave groove continuous with the punching hole is formed, and the back plate is thinner at the location of the concave groove. The backrest of the chair.

6. A seat on which a seated person sits, Legs that support the seat, and a backrest of the chair according to any one of claims 1 to 5. A chair comprising the same.

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