Shape-adaptive chair

Abstract

This shape-adaptive chair features a backrest that conforms to the shape of the sitter's back, providing ample cushioning with a simple structure and improving seating comfort. [Solution] The backrest portion 3 has a backrest frame 4 having rising portions 4a extending upward from the left and right sides of the seat portion 2, a receding portion 4b extending diagonally upward and backward from there, and a connecting portion 4c extending from there to the center in the left-right direction and connecting thereto, and a backrest seat 5 stretched over the backrest frame 4 with its lower end 5a being a free end, and the backrest seat 5 has a shape memory resin film 6 that softens with body temperature when the seated person's back is leaned against it and stretches to conform to the shape of the seated person's back, and returns to its original state after the seated person's back is separated, and an stretch limiting fabric 7 laminated on the shape memory resin film 6 that allows the stretching of the shape memory resin film 6 and limits the amount of stretching to a predetermined range.

Description

Technical Field

[0001] The present invention relates to a shape-adaptive chair in which the shape of the backrest deforms to match the individual shape of the spine of a seated person, and particularly relates to a shape-adaptive chair suitable for elderly people with a rounded back (kyphosis).

Background Art

[0002] Various chairs have been developed as chairs in which the shape of the backrest deforms to match the shape of the back of a seated person (see Patent Documents 1, 2 and 3).

[0003] In the chair described in Patent Document 1, a backrest membrane is stretched over a frame-shaped backrest frame via a plurality of coil springs, and the coil springs expand and contract appropriately according to the shape of the seated person's back, so that the shape of the backrest membrane fits the shape of the seated person's back.

[0004] In the chair described in Patent Document 2, a plurality of tension motors and pressure sensors are provided on the backrest membrane of the backrest, and a control unit operates each tension motor according to the output value of each pressure sensor to adjust the tension, thereby automatically adjusting the shape of the backrest membrane of the chair to match the individual back shape of the seated person.

[0005] In the chair described in Patent Document 3, a shape-memory resin layer is provided on the surface of a cushion member provided on the backrest, and the shape-memory resin layer deforms to fit the individual back shape of the seated person, thereby dispersing body pressure and improving seating comfort.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

[0007] By the way, the chair mentioned above still has room for improvement, as described below.

[0008] In the chair described in Patent Document 1, the shape of the backrest membrane fits the shape of the sitter's back by appropriately expanding and contracting the coil spring. However, the protruding part of the sitter's back that extends the coil spring is locally pressed by the spring force of the extended coil spring, making it difficult to obtain a comfortable fit.

[0009] The chair described in Patent Document 2 requires components such as pressure sensors, tension motors, and a control unit, as the control unit operates each tension motor according to the output value of each pressure sensor to adjust the tension. Considering the possibility of failure of each component, there is room for improvement in terms of reliability and durability. Furthermore, the combination of multiple components results in a complex structure, making cost increases unavoidable.

[0010] The chair described in Patent Document 3 has a shape-memory resin layer on the surface of the cushioning material, and the cushioning material elastically deforms to support the sitter's back. However, the thickness of the cushioning material becomes the upper limit of the deformation stroke. Therefore, depending on the degree of kyphosis of the sitter's back, a sufficient fit may not be obtained, and there is room for improvement in terms of seating comfort.

[0011] The present invention, conceived in consideration of the above circumstances, aims to provide a shape-adaptive chair in which the shape of the backrest automatically deforms to fit the individual back shape of the sitter, and which can exert sufficient cushion stroke with a simple structure, enhance the fit to various back shapes of the sitter, and improve the comfort of sitting. [Means for solving the problem]

[0012] The present invention, devised to achieve the above objective, is a shape-adaptive chair comprising a seat on which the seated person's buttocks rest and a backrest on which the seated person's back rests, wherein the backrest frame has rising sections extending upward from the left and right sides of the seat, respectively, receding sections extending diagonally upward and backward from these rising sections, and connecting sections extending from these receding sections to the center in the left-right direction to connect the left and right receding sections, and is fixed and stretched to the left and right rising sections, receding sections and connecting sections of the backrest frame. A shape-adaptive chair is provided, characterized in that it has a backrest seat with a free end at the lower end between the left and right raised sections, and the backrest seat has a shape-memory resin film that softens with the body temperature of the seated person's back when the seated person's back is leaned against it and stretches to conform to the shape of the seated person's back, and returns to its original state after the seated person's back is separated, and a stretch-restricting fabric that is laminated on the shape-memory resin film and has the function of allowing the stretching of the shape-memory resin film and limiting the amount of stretching to a predetermined range.

[0013] In the shape-adaptive chair according to the present invention, the raised portion of the backrest frame may extend diagonally upward and forward from the left and right sides of the seat, respectively.

[0014] In the shape-adaptive chair according to the present invention, a curved, recessed portion may be formed at the lower end of the backrest seat.

[0015] In the shape-adaptive chair according to the present invention, the backrest seat may have a double layer of shape-memory resin film only in the vicinity of the missing portion.

[0016] In the shape-adaptive chair according to the present invention, the seat portion has a cushion and a base plate that supports the cushion, and a recess is formed in the back of the base plate from the center, and the recess may be filled with the cushion.

[0017] In the shape-adaptive chair according to the present invention, the cushion may have a hard cushion disposed on the front side of the recess in the base plate and a soft cushion that is softer than the hard cushion and disposed on the back side including the recess in the base plate. [Effects of the Invention]

[0018] The shape-adaptive chair according to the present invention can exhibit the following effects. (1) When a person sits with their buttocks on the seat and leans their back against the backrest sheet stretched over the backrest frame, the shape-memory resin membrane of the backrest sheet softens due to the body heat of the person sitting on it. The lower end of the shape-memory resin membrane, which is the free end, deforms backward due to the weight of the person leaning on it, and the entire surface of the shape-memory resin membrane deforms to fit the shape of the person sitting on it. (2) Here, the backrest frame has upward-extending portions from the left and right sides of the seat, backward-extending portions that extend diagonally upward and backward from there, and connecting portions that extend from there to the center in the left-right direction and connect. As a result, the shape-memory resin film of the backrest seat stretched over the backrest frame has a shape that curves backward when viewed from the side. Therefore, when the seated person's back is leaned against the backrest seat, the necessary deformation stroke can be secured for the shape-memory resin film according to the shape of the individual seated person's back. (3) Furthermore, the amount of stretching of the shape-memory resin film, which deforms to conform to the shape of the seated person's back, is limited to a predetermined range by the stretch-restricting fabric laminated on the shape-memory resin film, so the shape-memory resin film will not stretch excessively without limit. Therefore, it is possible to avoid a situation in which the seated person's back, when leaning against the backrest seat, comes into contact with the connection part of the backrest frame, resulting in a deterioration of seating comfort due to excessive stretching of the shape-memory resin film. (4) When a seated person leaves their seat and their back is separated from the backrest seat, the shape-memory resin film of the backrest seat returns to its original state, and the stretch-restricting fabric laminated on the shape-memory resin film also returns to its original state, essentially resetting. Therefore, when another seated person leans their back against the backrest seat, the shape-memory resin film and stretch-restricting fabric of the backrest seat deform again in accordance with the shape of that seated person's back, as described above. (5) As described above, according to the shape-adaptive chair of the present invention, since the backrest frame has an ascending portion, a receding portion and a connecting portion, a necessary cushion stroke can be obtained for the shape-memory resin film of the backrest sheet stretched thereon, and the shape-memory resin film of the backrest sheet deforms according to the individual back shape of a seated person, so that fitting performance can be ensured; and the stretch-limiting fabric of the backrest sheet limits the stretch amount of the shape-memory resin film to a predetermined range, so that a situation where the back of the seated person hits the connecting portion of the backrest frame can be avoided. Therefore, a sufficient cushion stroke can be exerted with a simple structure, the fitting feeling for various shapes of the back of a seated person can be enhanced, and the comfort of sitting can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1] It is a front perspective view of a shape-adaptive chair according to an embodiment of the present invention, viewed from obliquely forward. [Figure 2] It is a rear perspective view of the shape-adaptive chair according to the present embodiment, viewed from obliquely rearward. [Figure 3] It is a right side view of the shape-adaptive chair according to the present embodiment, viewed from the right side. [Figure 4] It is a sectional view taken along line IV-IV in Figure 1, and is a partial sectional view of a backrest sheet of the shape-adaptive chair according to the present embodiment. [Figure 5] It is a sectional view taken along line V-V in Figure 1, and is a sectional view of a seat portion of the shape-adaptive chair according to the present embodiment. [Figure 6] It is a stress-strain diagram showing the relationship between tensile stress and tensile strain depending on temperature for the shape-memory resin film of the backrest sheet of the shape-adaptive chair according to the present embodiment. DESCRIPTION OF EMBODIMENTS

[0020] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely illustrative to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0021] (Overview of Shape-Adaptive Chair 1) As shown in Figures 1, 2, and 3, a shape-adaptive chair 1 according to one embodiment of the present invention comprises a seat 2 on which the seated person's buttocks rest and a backrest 3 on which the seated person's back rests. The backrest 3 comprises a backrest frame 4 and a backrest seat 5. The backrest frame 4 has upward-extending portions 4a from the left and right sides of the seat 2, backward-extending portions 4b from these upward-extending portions 4a diagonally upward and rearward, and connecting portions 4c extending from these backward-extending portions 4b to the center in the left-right direction, connecting the left and right backward-extending portions 4b. The backrest seat 5 is fixed and stretched to the left and right upward-extending portions 4a, backward-extending portions 4b and connecting portions 4c of the backrest frame 4, with the lower end 5a between the left and right upward-extending portions 4a being a free end.

[0022] As shown in Figure 4, the backrest seat 5 has a shape memory resin film 6 that softens with the body temperature of the sitter's back when the sitter's back is leaned against it, stretches to conform to the shape of the sitter's back, and returns to its original state after the sitter's back is separated from it, and a stretch-restricting fabric 7 that is laminated on the shape memory resin film 6 and has the function of allowing the stretching of the shape memory resin film 6 and limiting the amount of stretching to a predetermined range. The following describes each component.

[0023] (Backrest frame 4) As shown in Figures 1 to 3, the backrest frame has upward-extending sections 4a from the left and right sides of the seat 2, backward-extending sections 4b from these upward-extending sections 4a diagonally upward and rearward, and connecting sections 4c extending from these backward-extending sections 4b towards the center in the left-right direction to connect the left and right backward-extending sections. The backrest seat 5, which is fixed and stretched to the left and right upward-extending sections 4a, backward-extending sections 4b, and connecting section 4c, has a shape that curves backward when viewed from the side, as shown in Figure 3. Therefore, when the seated person's back is leaned against the backrest seat 5, the deformation stroke S (see Figures 1 and 3) required for the shape-memory resin film 6 (see Figure 4) of the backrest seat 5 can be secured according to the shape of the individual seated person's back.

[0024] As shown in Figure 3, the raised portion 4a of the backrest frame 4 extends diagonally forward and upward from the left and right sides of the seat 2, rather than vertically upward. With this configuration, when viewed from the side, the backrest seat 5 stretched over the backrest frame 4 has the portion connecting the raised portion 4a and the retracted portion 4b (the portion indicated by the dashed line L in Figure 1) as the foremost part. Therefore, when a sitter leans their back against the backrest seat 5, the sitter's back mainly contacts the portion connecting the raised portion 4a and the retracted portion 4b in the middle of the height of the backrest seat 5, and the entire surface of the shape-memory resin film 6 (see Figure 4) of the backrest seat 5 deforms to appropriately fit the shape of the sitter's back. In addition, the deformation stroke S (see Figure 3) of the shape-memory resin film 6 can be increased.

[0025] (Backrest seat 5) The backrest seat 5 shown in Figure 1, as shown in Figure 4, has a shape memory resin film 6 that softens with the body temperature of the sitter's back when the sitter's back is leaned against it, stretches to conform to the shape of the sitter's back, and returns to its original state after the sitter's back is separated from it, and a stretch-restricting fabric 7 that is laminated on the shape memory resin film 6 and has the function of allowing the stretching of the shape memory resin film 6 and limiting the amount of stretching to a predetermined range. In this embodiment, the stretch-restricting fabric 7 is laminated on the front and back surfaces of the shape memory resin film 7, but it may also be laminated on only the front surface or only the back surface of the shape memory resin film 6, or it may be adhered to each surface. The edges of the shape memory resin film 6 and the stretch-restricting fabric 6 laminated thereon are fixed and stretched to the rising portion 4a, the receding portion 4b and the connecting portion 4c of the backrest frame 4, and the lower end is a free end.

[0026] (Shape memory resin film 6) As shown in Figure 4, the shape memory resin film 6 of the backrest seat 5 is, for example, HUMOFIT®, a registered trademark of Mitsui Chemicals, Inc. As shown in Figure 6, HUMOFIT has a glass transition temperature (the temperature at which the polymer dramatically softens) of approximately 28 degrees Celsius, which is between room temperature (approximately 23 degrees Celsius) and human body temperature (approximately 36 degrees Celsius). Therefore, when the seated person's back is pressed against the shape memory resin film 6 (HUMOFIT sheet) of the backrest seat and body heat is transferred to the shape memory resin film 6 (HUMOFIT sheet), the temperature of the shape memory resin film 6 (HUMOFIT sheet) exceeds the glass transition temperature, and the shape memory resin film 6 (HUMOFIT sheet) deforms to fit the shape of the seated person's back. Subsequently, when the seated person leaves the seat and their back separates from the shape memory resin film 6 (HUMOFIT sheet), the shape memory resin film 6 (HUMOFIT sheet) slowly returns to its original state (shape before deformation). Note that in Figure 6, the MD of the tensile stress on the vertical axis represents the sheet molding direction (film molding direction) of the HUMOFIT sheet.

[0027] The material used for the shape memory resin film 6 (HUMOFIT sheet) is, for example, a resin containing a 4-methyl-1-pentene polymer. The 4-methyl-1-pentene polymer contains a first structural unit derived from 4-methyl-1-pentene and a second structural unit derived from a linear α-olefin with 2 to 3 carbon atoms other than 4-methyl-1-pentene. When the total of the first and second structural units is 100 mol%, it is preferable that the content of the first structural unit is 10 mol% to 90 mol% and the content of the second structural unit is 10 mol% to 90 mol%. The thickness of the shape memory resin film 6 (HUMOFIT sheet) is about 0.1 mm to 30 mm, and is preferably about 1 mm to 10 mm. The shape memory resin film 6 (HUMOFIT sheet) may have any of the following structures: net, mesh, nonwoven fabric, or woven fabric, and may have through holes to allow for breathability.

[0028] (Stretch restriction cloth 7) As shown in Figure 4, stretch-restricting fabric 7 is laminated to the front and back surfaces of the shape memory resin film 6. This fabric has the function of allowing the shape memory resin film 6 to stretch while limiting the amount of stretching to a predetermined range. The stretch-restricting fabric 7 is made of a fabric using elastic fibers such as polyurethane fibers or PTT fibers (polytrimethylene terephthalate), such as so-called stretch fabric or high-tension fabric. The stretch limit of the elastic fibers becomes the limit of the amount of stretch of the shape memory resin film 6. As a result, the amount of stretch of the shape memory resin film 6 is limited to a predetermined range. Therefore, when the seated person's back is leaned against the backrest seat 5 shown in Figure 3, it is possible to avoid a situation where the shape memory resin film 6 (see Figure 4) of the backrest seat 5 stretches to the limit of the deformation stroke S (see Figure 3) and the seated person's back hits the connection part 4c of the backrest frame 4.

[0029] Furthermore, the stretch-restricting fabric 7 shown in Figure 4 may be a woven fabric of the aforementioned elastic fibers (polyurethane fibers, etc.) and non-elastic fibers (polyester fibers, etc.), so that the stretchability of the shape memory resin film is ensured by the elastic fibers, while the amount of stretching of the shape memory resin film is limited to a predetermined range by the non-elastic fibers. The non-elastic fibers are woven in with a predetermined margin to allow the elastic fibers to stretch to a predetermined range.

[0030] (Missing part) As shown in Figures 1 and 2, a curved cutout 8 is formed at the lower end 5a of the backrest seat 5. With this configuration, when the seated person's buttocks are placed on the seat 2, the buttocks fit into the cutout 8, so the seated person sits towards the back of the seat 2. Therefore, a proper seating posture can be achieved.

[0031] (Double arrangement of shape memory resin film 6) As shown in Figure 4, the backrest seat 5 has a double layer of shape-memory resin film 6 only in the vicinity of the cutout 8 shown in Figure 1 (the part below the dashed line L in Figure 1). With this configuration, when a sitter sits on the back of the seat, the shape-memory resin film 6 is double-layered along the cutout 8 where the sitter's buttocks fit, so excessive stretching of the cutout 8 is prevented and the buttocks are properly supported. Therefore, the sitting comfort is improved.

[0032] (Seat part 2) As shown in Figure 5, the seat 2 has a cushion 9, a base plate 10 that supports the cushion 9, and a cover 11 that covers the cushion 9 and is fixed to the base plate 10. The base plate 10 has a recess 12 formed towards the back of the center, and the cushion 9 is filled into the recess 12. With this configuration, when a person sits on the seat 2, their buttocks settle into the recess 12 at the back of the seat 2. As a result, the person sits towards the back of the seat 2, and their sitting posture becomes more stable. In addition, the thickness of the cushion 9 in the recess 12 is increased, improving the comfort of sitting.

[0033] (Hard cushion 9a, soft cushion 9b) As shown in Figure 5, the cushion 9 of the seat 2 has a hard cushion 9a positioned in front of the recess 12 of the base plate 10, and a soft cushion 9b positioned in the back, including the recess 12 of the base plate 10. The soft cushion 9b is softer than the hard cushion 9a. With this configuration, the hard cushion 9a is positioned in front of the recess 12 of the seat 2, and the soft cushion 9b is positioned in the back, including the recess 12 of the seat 2, so that the sitter can sit so that they fit into the recess 12 at the back of the seat 2, resulting in a stable sitting posture.

[0034] (Effects / Actions) According to the shape-adaptive chair 1 of this embodiment, the following actions and effects can be achieved.

[0035] In Figure 1, when a person sits with their buttocks on the seat 2 and leans their back against the backrest seat 5 stretched over the backrest frame 4, the shape-memory resin film 6 (see Figure 4) of the backrest seat 5 softens due to the body heat of the person sitting on it. The lower end of the shape-memory resin film 6, which is a free end, deforms backward due to the weight of the person leaning on it, and the entire surface of the shape-memory resin film 6 deforms to fit the shape of the person sitting on it.

[0036] Here, as shown in Figure 3, the backrest frame 4 has an upward-extending portion 4a from the left and right sides of the seat 2, a backward-extending portion 4b from there diagonally upward and rearward, and a connecting portion 4c that extends from there to the center in the left-right direction and connects them. As a result, the shape-memory resin film 6 (see Figure 4) of the backrest seat 5 stretched over the backrest frame 4 has a shape that curves backward when viewed from the side. Therefore, when the seated person's back is leaned against the backrest seat 5, the deformation stroke S (see Figures 1 and 3) required for the shape-memory resin film 6 can be secured according to the shape of the individual seated person's back.

[0037] Furthermore, the amount of stretching of the shape-memory resin film 6 shown in Figure 4, which deforms to conform to the shape of the seated person's back, is limited to a predetermined range by the stretch-restricting fabric 7 laminated on the shape-memory resin film 6, so the shape-memory resin film 6 will not stretch excessively without limit. Therefore, it is possible to avoid a situation where the shape-memory resin film 6 stretches excessively, causing the seated person's back, when leaning against the backrest seat 5 shown in Figure 3, to come into contact with the connection part 4c of the backrest frame 4, thus worsening the seating comfort.

[0038] Furthermore, when a seated person leaves their seat and their back separates from the backrest seat 5 shown in Figure 3, the shape-memory resin film 6 of the backrest seat 5 returns to its original state (shape), and the stretch-restricting fabric 7 laminated on the shape-memory resin film 6 also returns to its original state, essentially resetting. Therefore, when another seated person leans their back against the backrest seat 5, the shape-memory resin film 6 and stretch-restricting fabric 7 of the backrest seat 5 deform again as described above, according to the shape of that seated person's back.

[0039] In summary, according to the shape-adaptive chair 1 of this embodiment, as shown in Figure 3, the backrest frame 4 has an upward portion 4a, a backward portion 4b, and a connecting portion 4c, so that a sufficient cushion stroke S can be obtained for the shape-memory resin membrane 6 of the backrest seat 5 stretched thereon. The shape-memory resin membrane 6 of the backrest seat 5 shown in Figure 4 deforms according to the shape of the individual back of the sitter, thereby ensuring a good fit. The stretch-restricting fabric 7 of the backrest seat 6 limits the amount of stretch of the shape-memory resin membrane 6 to a predetermined range, thus preventing the sitter's back from hitting the connecting portion 4c of the backrest frame 4 and worsening the comfort of sitting.

[0040] Furthermore, the shape-adaptive chair 1 according to this embodiment does not use any complex parts such as sensors or motors as in the prior art, so there is no need to worry about malfunctions, it is highly reliable and durable, and has a simple structure and low cost. In other words, it can provide sufficient cushion stroke with a simple structure and low cost, and can improve the fit to various back shapes of the sitter, thereby improving the comfort of sitting. Therefore, it is suitable as a shape-adaptive chair for use in facilities such as nursing homes where there are many people with kyphosis.

[0041] Preferred embodiments of the present invention have been described above with reference to the attached drawings. However, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications or alterations within the scope of the claims also fall within the technical scope of the present invention. [Industrial applicability]

[0042] The present invention relates to a shape-adaptive chair in which the shape of the backrest changes to conform to the individual back shape of the sitter, and is particularly applicable to shape-adaptive chairs used by elderly people with kyphosis (rounded back). [Explanation of Symbols]

[0043] 1. Shape-adaptive chair 2 Seat part 3. Backrest 4. Backrest frame 4a Rising section 4b Rear section 4c connector 5. Backrest seat 5a Bottom end 6. Shape memory resin film 7. Stretch-restricting cloth 8 Missing parts 9 cushions 9a Hard cushion 9b Soft cushion 10 Bottom plate 11 Cover 12 Recessed area

Claims

1. A shape-adaptive chair comprising a seat on which the seated person's buttocks rest and a backrest on which the seated person's back rests, The backrest portion comprises a backrest frame having rising portions extending upward from the left and right sides of the seat portion, receding portions extending diagonally upward and rearward from these rising portions, and connecting portions extending from these receding portions to the center in the left-right direction to connect the left and right receding portions, and a backrest seat fixed and stretched to the left and right rising portions, receding portions, and connecting portions of the backrest frame, with the lower end between the left and right rising portions being a free end. A shape-adaptive chair characterized in that the backrest seat has a shape-memory resin film that softens with the body temperature of the sitter's back when the sitter's back is leaned against it, stretches to conform to the shape of the sitter's back, and returns to its original state after the sitter's back is separated from it, and a stretch-restricting fabric laminated on the shape-memory resin film that allows the stretching of the shape-memory resin film and has the function of limiting the amount of stretching to a predetermined range.

2. The shape-adaptive chair according to claim 1, characterized in that the raised portion of the backrest frame extends diagonally forward and upward from the left and right sides of the seat, respectively.

3. The shape-adaptive chair according to claim 1 or 2, characterized in that a curved, missing portion is formed at the lower end of the backrest seat.

4. The shape-adaptive chair according to claim 3, characterized in that the backrest seat has the shape-memory resin film doubled only in the vicinity of the missing portion.

5. The shape-adaptive chair according to claim 1 or 2, characterized in that the seat portion has a cushion and a base plate that supports the cushion, a recess is formed in the base plate on the side further back from the center, and the cushion fills the recess.

6. The shape-adaptive chair according to claim 5, characterized in that the cushion comprises a hard cushion disposed on the front side of the recessed portion of the base plate and a soft cushion that is softer than the hard cushion and disposed on the rear side of the base plate including the recessed portion.

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