BACK SUPPORT ASSEMBLY AND CHAIR

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims priority to Chinese Patent Application No. 202420245707.8, filed with the Chinese Patent Office on Jan. 31, 2024, titled “BACK SUPPORT ASSEMBLY AND CHAIR”, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

Embodiments of the present disclosure relate to the technical field of seating furniture, and in particular, relate to a back support assembly and a chair.

BACKGROUND

Chairs, as essential items for daily life and office work, are increasingly expected to provide a high level of comfort. Currently, most chairs use elastic mesh fabric to support the back of the user, to prevent discomfort when leaning against.

Although elastic mesh fabric better adapts to the shape of the user's back and deform accordingly under pressure, the performance of the elastic mesh fabric is limited by its elasticity. Prolonged pressure may cause the mesh fabric to loosen, and thus to fail to provide reliable back support.

SUMMARY

In view of the above problem, embodiments of the present disclosure provide a back support assembly and a chair, which are capable of still providing reliably back support even after long-time use, and meanwhile ensuring leaning comfort.

According to one aspect of the embodiments of the present disclosure, a back support assembly is provided. The back support assembly includes: a back support frame, an elastic support member, a plurality of elastic support rods, and an elastic support sheet. The back support frame has a connection portion. The elastic support member is in a strip shape. Two ends of the elastic support member are connected to the connection portion, and a middle section of the elastic support member is bent towards a direction facing away from the connection portion. The plurality of elastic support rods arranged at an angle to each other. One end of each of the plurality of elastic support rods is connected to a side, facing away from the connection portion, of the middle section of the elastic support member, and the other end of the elastic support rod is bent towards a side facing away from the elastic support member and is connected to a back face of the elastic support sheet. A front face of the elastic support sheet allows a human back to lean against.

In some embodiments, the elastic support sheet includes a skeleton portion and a flexible portion. The flexible portion is arranged around an outer periphery of the skeleton portion. A stiffness of the skeleton portion is greater than a stiffness of the flexible portion. One end, facing away from the elastic support member, of the elastic support rod is connected to a back face of the skeleton portion.

In some embodiments, the skeleton portion and the flexible portion are made of a same material, and are designed as an integral structure. A thickness of the skeleton portion is greater than a thickness of the flexible portion, such that the stiffness of the skeleton portion is greater than the stiffness of the flexible portion.

In some embodiments, ventilation holes are defined in the flexible portion.

In some embodiments, a mesh fabric mounting frame surrounding an outer periphery of the elastic support sheet is arranged on the back support frame. The mesh mounting frame is configured to be connected to an edge of mesh fabric. The front face of the elastic support sheet is configured to be abutted against the mesh fabric and allow, together with the mesh fabric, the human back to lean against.

In some embodiments, the elastic support sheet is in a four-petal shape that is mirror-symmetrical relative to a vertical line of symmetry.

In some embodiments, at least three of said elastic support rods are arranged. At least two of the at least three elastic support rods are connected between back faces of left and right petals in the elastic support sheet and the middle section of the elastic support member. At least one of the at least three elastic support rods is connected between back faces of a top petal in the elastic support sheet and the middle section of the elastic support member.

In some embodiments, the connection portion includes a first connection portion and a second connection portion. A first end of the elastic support member is rotatably connected to the first connection portion. A second end of the elastic support member is slidably connected to the second connection portion along an extension direction of the elastic support member. The second end of the elastic support member is configured to adjust an elastic force of the elastic support member during sliding relative to the second connection portion.

In some embodiments, a mounting slot is defined in the second connection portion, and the second end of the elastic support member extends into the mounting slot and is slidable in the mounting slot. An adjustment screw is rotatably arranged in the mounting slot, wherein a first end of the adjustment screw is threaded to the second end of the elastic support member extending into the mounting slot, and a knob is arranged at a second end of the adjustment screw. An opening is defined in a wall of the mounting slot, wherein a portion of the knob extends out of the opening, and the portion of the knob extending out of the opening is configured to receive a force and rotate to drive the adjustment screw to rotate, such that the second end of the elastic support member is driven to slide in the mounting slot to adjust the elastic force of the elastic support member.

According to another aspect of the embodiments of the present disclosure, a chair is provided. The chair includes the back support assembly as described above.

When the back support assembly according to the present disclosure is applied to a chair, the back of a user is in contact with the elastic support sheet and exerts force when the is seated in the chair and lean against the backrest of the chair. First, the elastic support sheet is capable of deforming to an extent according to the shape of the back of the user and an applied force. In this way, initial cushioning and support are provided. Next, the elastic support sheet transfers the pressure to a plurality of elastic support rods. These rods expand and deform under a force, allowing the elastic support sheet to move backward by a distance. This creates a greater degree of cushioning, while a restoring force generated by the deformation upon cushioning provides adequate support for the elastic support sheet, ensuring leaning comfort. Finally, the plurality of elastic support rods further transfer the force to the elastic support member, and the elastic support member deform under a force, such that additional cushioning and support are provided.

Based on this, compared with the traditional mesh fabric support, the back support assembly according to the present disclosure maintains elastic deformation capabilities of the elastic support member, the elastic support rods, and the elastic support sheet over the lifetime of the back support assembly. Even after long-term use, cushioning and support when the user leans against are still effectively ensured.

The above description only summarizes the technical solutions of the present disclosure. Specific embodiments of the present disclosure are described hereinafter to better and clearer understand the technical solutions of the present disclosure, to practice the technical solutions based on the disclosure of the specification, and to make the above and other objectives, features and advantages of the present disclosure more apparent and understandable.

BRIEF DESCRIPTION OF THE DRAWINGS

By reading the detailed description of preferred embodiments hereinafter, various other advantages and beneficial effects become clear and apparent for persons of ordinary skill in the art. The accompanying drawings are merely for illustrating the preferred embodiments, but shall not be construed as limiting the present disclosure. In all the accompanying drawings, like reference numerals denote like parts. In the drawings:

FIG. 1 is a schematic structural view of a back support assembly according to some embodiments of the present disclosure;

FIG. 2 is a schematic exploded view of the back support assembly according to some embodiments of the present disclosure;

FIG. 3 is a schematic front structural view of the back support assembly with a back support frame removed according to some embodiments of the present disclosure;

FIG. 4 is a schematic rear structural view of the back support assembly with the back support frame removed according to some embodiments of the present disclosure;

FIG. 5 is a schematic front structural view of the back support assembly according to some embodiments of the present disclosure;

FIG. 6A is a schematic top view of an edge shape of mesh fabric according to some embodiments of the present disclosure;

FIG. 6B is a schematic side view of the edge shape of the mesh fabric according to some embodiments of the present disclosure;

FIG. 7 is a schematic front structural view of a elastic support sheet in the back support assembly according to some embodiments of the present disclosure;

FIG. 8 is a schematic structural view of the elastic support sheet and a plurality of elastic support rods in the back support assembly according to some embodiments of the present disclosure;

FIG. 9 is a schematic structural view of the back support frame and an elastic support member in the back support assembly according to some embodiments of the present disclosure;

FIG. 10 is a schematic cross-sectional side view of the back support assembly according to some embodiments of the present disclosure;

FIG. 11 is schematic a structural view of engagement between the elastic support assembly and a mounting slot inside the back support assembly according to some embodiments of the present disclosure; and

FIG. 12 is a structural block view of a chair according to some embodiments of the present disclosure.

Reference numerals in the embodiments and denotations thereof:

• • 100—back support assembly;
  • 110—back support frame; 111—connection portion; 1111—first connection portion, 1112—second connection portion 11121—mounting slot; 11122—opening; 11123—limiting post; 1113—adjustment screw; 1114—knob; 112—mesh fabric mounting frame;
  • 120—elastic support member; 1201—first end; 1202—second end; 12021—guiding hole; 121—notch; 122—spacer;
  • 130—elastic support rod;
  • 140—elastic support sheet; 141—skeleton portion; 142—flexible portion; 1421—ventilation hole;
  • 200—edge of mesh fabric;
  • 300—chair.

DETAILED DESCRIPTION

The embodiments containing the technical solutions of the present disclosure are described in detail with reference to the accompanying drawings. The embodiments hereinafter are only used to clearly describe the technical solutions of the present disclosure. Therefore, these embodiments are only used as examples, but are not intended to limit the protection scope of the present disclosure.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains. The terms used herein in the specification of present disclosure are only intended to illustrate the specific embodiments of the present disclosure, instead of limiting the present disclosure. The terms “comprise,” “include,” and any variations thereof in the specification, claims, and the description of the drawings of the present disclosure are intended to cover a non-exclusive inclusion.

In the description of the present disclosure, the terms “first,” “second,” and the like are only used for distinguishing different objects, but shall not be understood as indication or implication of relative importance or implicit indication of the number of the specific technical features, the specific sequence or priorities. In the description of the embodiments of the present disclosure, the term “multiple” or “a plurality of” signifies at least two, unless otherwise specified.

The terms “example” and “embodiment” in this specification signify that the specific characteristic, structures or features described with reference to the embodiments may be covered in at least one embodiment of the present disclosure. This term, when appearing in various parts of the specification, neither indicates the same embodiment, nor indicates an independent or optional embodiment that is exclusive of the other embodiments. A person skilled in the art would implicitly or explicitly understand that the embodiments described in this specification may be incorporated with other embodiments.

In the description of the embodiments of the present disclosure, the term “and/or” is merely an association relationship for describing associated objects, which represents that there may exist three types of relationships. For example, the phrase “A and/or B” may indicate (A), (B), or (A and B). In addition, the forward-slash symbol “/” generally represents an “or” relationship between associated objects before and after the symbol.

In the description of the embodiments of the present disclosure, the term “multiple” or “a plurality of” signifies more than two (including two), unless otherwise specified. Likewise, the term “a plurality of groups” or “multiple groups” signifies more than two groups (including two groups), and the term “a plurality of pieces” or “multiple pieces” signifies more than two pieces (including two pieces).

In the description of the embodiments of the present disclosure, it should be understood that the terms “central,” “transversal,” “longitudinal,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” “circumferential,” and the like indicate orientations and position relationships which are based on the illustrations in the accompanying drawings, and these terms are merely for ease and brevity of the description, instead of indicating or implying that the devices or elements shall have a particular orientation and shall be structured and operated based on the particular orientation. Accordingly, these terms shall not be construed as limiting the present disclosure.

In the description of the embodiments of the present disclosure, it should be noted that unless otherwise specified and defined, the terms “mounted,” “coupled,” “connected,” “secured,” and derivative forms thereof shall be understood in a broad sense, which, for example, may be understood as secured connection, detachable connection or integral connection; may be understood as mechanical connection or electrical connection, or understood as direct connection, indirect connection via an intermediate medium, or communication between the interiors of two elements or interactions between two elements. Persons of ordinary skill in the art may understand the specific meanings of the above terms in the embodiments of the present disclosure according to the actual circumstances and contexts.

For a chair with a back support made of elastic mesh fabric, an annular mounting frame is generally arranged at the rear of the chair, and edges of the elastic mesh fabric are secured to the mounting frame. In the case that a force is applied by the back of a user, the elastic mesh fabric stretches, and the center of the mounting frame is hollowed out to allow the elastic mesh fabric to deform rearward, such that the elastic mesh fabric is allowed to conform more closely to the back of the user. This provides cushioning and support to the back of the user via the elastic mesh fabric.

However, with the passage of time, the elastic mesh fabric tends to undergo irreversible deformation. That is, even not subjected to pressure, the elastic mesh fabric fails to fully return to its original state. As a result, the elastic mesh fabric becomes slack and no longer provides reliable cushioning and support.

In view of the above issues, the present disclosure first employs an elastic support sheet in contact with the back of the user to provide support. Since the elastic support sheet is capable of deforming under the force applied by the back of the user, comfort is ensured for the back of the user during leaning. Furthermore, to provide sufficient cushioning and support to the back of the user, the present disclosure also adopts a dual elastic support structure. Specifically, a plurality of elastic support rods and an elastic support member are sequentially arranged on the rear face of the elastic support sheet. The plurality of elastic support rods form a first layer of elastic support, and these rods are capable of deforming to varying degrees, such that different levels of cushioning and support are provided to different areas of the elastic support sheet. In other words, the system is capable of offering varying levels of support to different areas of the back of the user depending on the forces applied to those areas. The elastic support member forms a second layer of elastic support, primarily providing cushioning and support for the overall structure composed of the elastic support sheet and the plurality of elastic support rods, thereby further ensuring the cushioning and support effect when the user leans against the elastic support sheet, and enhancing the leaning comfort. The entire back support system differs significantly from the mesh fabric support. Although the elastic support sheet, the plurality of support rods, and the elastic support member all possess elasticity, they are relatively more rigid structures compared with the mesh fabric. Therefore, as the system is used over time, their inherent elastic deformation capabilities are less affected, such that reliable cushioning and support are still provided for the user even after long-term use.

According to one aspect of the embodiments of the present disclosure, a back support assembly is provided. The back support assembly is applicable to, but is not limited to, home chairs, office chairs, ergonomic chairs, gaming chairs, and the like.

Referring to FIGS. 1 to 3, FIG. 1 illustrates a three-dimensional structure of a back support assembly according some embodiments of the present disclosure, FIG. 2 illustrates an exploded view of a back support assembly, and FIG. 3 illustrates a structure of a back support assembly with a back support frame removed. As illustrated in FIG. 1 and FIG. 2, the back support assembly 100 includes a back support frame 110, an elastic support member 120, an elastic support rod 130, and an elastic support sheet 140. A connection portion 111 is arranged on the back support frame 110. The elastic support member 120 is in a strip shape. Two ends of the elastic support member 120 are connected to the connection portion 111. A middle section of the elastic support member 120 is bent towards a direction facing away from the connection portion 111. As illustrated in FIG. 3, a plurality of elastic support rods 130 are arranged. The plurality of elastic support rods 130 are arranged at an angle to each other. One end of each of the plurality of elastic support rods 130 is connected to a side, facing away from the connection portion 111, of the middle section of the elastic support member 120, and the other end of the elastic support rod 130 is bent towards a side facing away from the elastic support member 120 and is connected to a back face of the elastic support sheet 140. A front face of the elastic support sheet 140 is design for a human back to lean against.

The back support frame 110, as the base of the entire back support assembly 100, is typically fixedly connected to a chassis of the chair at a bottom end. The back support frame 110 serves as a support structure allowing mounting, attachment and securing of other components on the back of the chair. In the specific embodiment as illustrated in FIG. 1, the bottom end of the back support frame 110 extends forward and is securely fitted or attached to the chassis (not illustrated) of the chair, such that the entire back support assembly 100 is secured to the chassis of the chair.

As illustrated in FIG. 2, the elastic support member 120 may be configured as a strip extending vertically, or alternatively, configured as a strip extending in a horizontal or inclined direction. Additionally, a plurality of elastic support members 120 may be arranged. The plurality of elastic support members 120 may either be parallel to each other or cross over one another.

In the specific embodiment as illustrated in FIG. 2, the elastic support member 120 is shaped in a serpentine curve, with notches 121 in both sides, thereby forming a rib-like structure. This design allows the elastic support member 120, when bent forward, to reduce its overall curvature under the force applied by back-leaning against by the user, such that both cushioning and support are provided. Furthermore, different sections of the elastic support member 120, at the notches 121, may deform to varying degrees based on the magnitude of a force they receive, such that better cushioning and support are provided for the user. Additionally, for enhancement of the support force of the elastic support member 120, the notches 121 may be designed to have an inverted “T” shaped cross-section, and a spacer 122 is filled into the notches 121. The spacer 122 limits the degree of deformation of the elastic support member 120 at the notches 121, thereby improving the support force for the back of the user. In some other embodiments, the elastic support member 120 may also employ an elastic sheet or the like structure.

As illustrated in FIG. 3, the plurality of elastic support rods 130 may be an integral structure with one ends thereof connected to each other, and the connected end is connected to the elastic support member 120. The other ends of the plurality of elastic support rods 130 curve toward the elastic support sheet 140 and are connected at different positions on a back face of the elastic support sheet 140.

The plurality of elastic support rods 130 being arranged at an angle to each other means that a specific angle is defined between each two elastic supports rod 130. For example, the angle may be 30°, 60°, 90°, 120°, or the like. This arrangement allows the plurality of elastic support rods 130 to collectively form a frame that opens from the elastic support member 120 to the elastic support sheet 140. When a force is applied to the elastic support sheet 140 by the back of the user, the plurality of elastic support rods 130 undergo elastic deformation in an expansion direction, such that cushioning and support are provided for the back of the user.

The front face of the elastic support sheet 140, when subjected to the force from the back of the user, may deform in response to the force due to inherent elastic properties thereof, such that leaning comfort is ensured. Furthermore, since one end of the elastic support rods 130 is connected to the back surface of the elastic support sheet 140, and the other end is connected to the elastic support member 120, with the elastic support rods 130 curving from the elastic support member 120 towards the elastic support sheet 140, the plurality of elastic support rods 130 can undergo deformation in an expanding state when pressure is applied through the elastic support sheet 140. This provides reliable cushioning for the back of the user during leaning.

When the back support assembly 100 according to the present disclosure is applied to a chair, the back of a user is in contact with the elastic support sheet 140 and exerts force when the is seated in the chair and lean against the backrest of the chair. First, the elastic support sheet 140 is capable of deforming to an extent according to the shape of the back of the user and an applied force. In this way, initial cushioning and support are provided. Next, the elastic support sheet 140 transfers the pressure to a plurality of elastic support rods 130. These elastic support rods 130 suffers a force, and expand and deform under the force, such that the elastic support sheet 140 is capable of moving backward by a distance. This creates a greater degree of cushioning, while a restoring force generated by the deformation upon cushioning provides adequate support for the elastic support sheet 140, thereby ensuring leaning comfort. Finally, the plurality of elastic support rods 130 further transfer the force to the elastic support member 120, and the elastic support member 120 suffers from the force and deform under the force, such that additional cushioning and support are provided.

Based on this, compared with the traditional mesh fabric support, the back support assembly 100 according to the present disclosure maintains elastic deformation capabilities of the elastic support member 120, the elastic support rods 130, and the elastic support sheet 140 over the lifetime of the back support assembly 100. Even after long-term use, cushioning and support when the user leans against are still effectively ensured.

In the case that the user leans against the elastic support sheet 140, where the stiffness of the elastic support sheet 140 is too high, that is, it is difficult for the elastic support sheet 140 to deform, the sharp edges and corners on the elastic support sheet 140 may cause discomfort. Conversely, in the case that the stiffness of the elastic support sheet 140 is too low, excessive deformation may occur during leaning, which not only fails to provide adequate support but may also cause discomfort at the connection points between the elastic support sheet 140 and the elastic support rods 130.

For further improvement of the leaning comfort, the present disclosure proposes an embodiment. Referring to FIG. 4. FIG. 4 illustrates a back structure of an elastic support sheet and a plurality of elastic support rods. As illustrated in FIG. 14, the elastic support sheet 140 includes a skeleton portion 141 and a flexible portion 142. The flexible portion 142 is arranged around an outer periphery of the skeleton portion 141. The stiffness of the skeleton portion 141 is greater than the stiffness of the flexible portion 142. One end, facing away from the elastic support member 120, of the elastic support rod 130 is connected to the back face of the skeleton portion 141.

Based on this, in this embodiment, to address the issue of discomfort caused by the connection points between the elastic support sheet 140 and the elastic support rods 130 in the case that the stiffness of the elastic support sheet 140 is low, the middle region of the elastic support sheet 140 is designed as a high-stiffness framework section 141. One end of the elastic support rod 130 is connected to the back face of the skeleton portion 141. The high-stiffness skeleton portion 141 helps to minimize the transfer of excessive force from the front face of the elastic support sheet 140 to the back of the user, such that leaning comfort is ensured. To address the issue of discomfort caused by the sharp edges of the elastic support sheet 140, the edge areas of the elastic support sheet 140, that is, the areas surrounding the framework section 141, are designed as the low-stiffness flexible portion 142. These flexible portions 142, with their higher deformation capabilities, ensure greater degree of deformation in response to the force applied by the back of the user, such that discomfort caused by the edges of the elastic support sheet is avoided.

Specifically, the skeleton portion 141 and the flexible portion 142 may be made of different materials to create a stiffness difference therebetween. The skeleton portion 141 and the flexible portion 142, which are made different materials, may be integrally molded, or individually produced and then bonded together by an adhesive, heat sealing, or other methods.

Additionally, one possible implementation could involve molding a larger support sheet and a smaller support sheet, and the smaller sheet is attached to the central area on the back of the larger sheet. In this way, the smaller and larger support sheets, together with their respective areas in contact, form the skeleton portion 141, while the outer edge of the larger sheet, which is not in contact with the smaller sheet, forms the flexible portion 142. In this embodiment, the smaller and larger support sheets could be made of the same or different materials.

In addition to the implementation described above, the skeleton portion 141 and the flexible portion 142 may also be made of the same material, with differences in stiffness achieved by altering other parameters. In an embodiment, as illustrated in FIG. 4, the skeleton portion 141 and the flexible portion 142 are made of the same material and are formed as an integral structure, wherein the thickness of the skeleton portion 141 is greater than that of the flexible portion 142, such that the stiffness of the skeleton portion 141 is greater than that of the flexible portion 142.

In this embodiment, since the skeleton portion 141 and the flexible portion 142 are made from the same material, the process of molding these two portions into one piece is simplified, facilitating more efficient mass production of the elastic support sheet 140. Additionally, the skeleton portion 141 and the flexible portion 142 are designed as an integral structure eliminates the need for assembly steps, which further improves the overall assembly efficiency of the back support assembly 100. Moreover, considering that the thickness is proportional to the rigidity of the material in the case that both the skeleton portion 141 and the flexible portion 142 are made of the same material, the thickness of the skeleton portion 141 is set to be greater than that of the flexible portion 142 to ensure the required difference in rigidity between the two portions, as specified in the above embodiment.

Considering that the elastic support sheet is in full contact with the back of the user, and long-term contact may cause discomfort due to limited breathability, this embodiment proposes a solution as illustrated in FIG. 4. Specifically, ventilation holes 1421 are defined in the flexible portion 142.

Since defining holes may affect the structural integrity of the elastic support sheet 140, the skeleton portion 141, as a primary support member, has higher rigidity. In the case that holes are defined in the skeleton portion 141, it could lead to excessive deformation under a larger force, which potentially causes fractures or other risks. On the contrary, the flexible portion 142 bears a smaller force during use, has lower rigidity, and is capable of deforming more easily. Defining holes in the flexible portion 142 not only exerts minimal impact on the overall structural strength of the elastic support sheet 140, but also reduces the rigidity of the flexible portion 142, that is, increasing its ability to deform. In this way, comfort is enhanced while breathability is improved, and leaning comfort is further improved.

For more comprehensive cushioning and support to the entire back of the user, the present disclosure further proposes an embodiment. As illustrated in FIGS. 1 and 2, the back support frame 110 further includes a mesh fabric mounting frame 112 surrounding an outer periphery of the elastic support sheet 140. The mesh fabric mounting frame 112 is configured to be connected to the edge of mesh fabric (not illustrated in the drawings). The front surface of the elastic support sheet 140 is in contact with the mesh fabric, and provides, together with the mesh fabric, provide support for the back of the user when leaning against.

It should be noted that the structure illustrated in FIGS. 1 and 2 may only represent a part of the mesh fabric mounting frame 112. In addition, the mesh fabric mounting frame 112 may further include a semi-ring-shaped frame connected to the upper part of the structure illustrated, such that the entire mesh fabric mounting frame 112 forms an enclosed ring structure, which is securely connected to the entire outer edge of the mesh fabric.

By arranging the front surface of the elastic support sheet 140 to be abutted against the mesh fabric mounted on the mesh fabric mounting frame 112, when the user leans against the elastic support sheet, a primary force bearing region in the middle of the back of the user is supported by the elastic support sheet 140 and the plurality of elastic support rods 130 and the elastic support assembly 120 at the rear end thereof. This ensures that sufficient support is provided. On the contrary, relatively small support is required for the edges of the back of the user. Therefore, the support for these areas may be provided by the mesh fabric to ensure comprehensive and comfortable support.

To ensure that the mesh fabric better conforms to the elastic support sheet 140 to improve the leaning comfort of the user, the present disclosure further proposes an embodiment. Specifically, referring to FIG. 5, FIG. 5 illustrates the structure of the front surface of the back support assembly. As illustrated in FIG. 5, the elastic support sheet 140 is in a four-petal shape that is mirror-symmetrical relative to a vertical line of symmetry.

The mesh fabric is generally in a hyperbolic shape. That is, as illustrated in FIG. 6A, when viewed from a top-down perspective, the edges 200 of the mesh fabric protrude forward on both sides and curve inward in the center. As illustrated in FIG. 6B, when viewed from the side, the edges 200 of the mesh fabric form an overall forward-bending curve. In this case, conventional shapes of the elastic support sheet 140, for example, square, round, or oval shapes, fail to provide sufficient contact and fit with the mesh fabric. However, in the petal-shaped elastic support sheet 140, each petal resembles a cantilever, with one end of the cantilever being free. As a result, each petal may undergo significant deformation, such that the petal is fully adaptive to the shape of the mesh fabric and is in tight fit with the mesh fabric. In this way, the elastic support sheet 140 and the mesh fabric together provide reliable back support for the user.

Additionally, where the elastic support sheet 140 is designed to a petal shape including a plurality of petals, it is inevitable that each petal is thin, and consequently breakage of the petal may easily occur. In this regard, based on the force applied to the elastic support sheet 140 during leaning by the human back, force distribution on the elastic support sheet 140 is nearly symmetrical relative to a vertical line of symmetry. Therefore, considering both the degree of fitness between the elastic support sheet 140 and the mesh fabric, as well as the structural stability of the elastic support sheet 140, the elastic support sheet 140 is configured in a four-petal shape that is mirror-symmetrical relative to the vertical line of symmetry. This mirror-symmetrical structure corresponds to the force distribution applied when the user leans against the elastic support sheet, and effective support is provided to various positions on the back of the user. The four-petal shape ensures close fit with the mesh fabric while minimizing any adverse impact on the structural strength of the elastic support sheet 140.

As illustrated in the front view of the elastic support sheet 140 in FIG. 7, in some embodiments, a dimension D₁ along a vertical direction of a top petal is greater than a dimension D₂ along the vertical direction of a bottom petal in the elastic support sheet 140.

Since the four-petal-shaped elastic support sheet 140 is symmetrically mirrored along the vertical line of symmetry, the top petal directly provides support to the spinal region of the user when the user leans against the elastic support sheet. By configuring the dimension D₁ along the vertical direction of the top petal to be larger, the spline of the user may be more comprehensively covered and supported. Additionally, the cantilever structure formed by the top petals may undergo greater deformation, such that enhanced cushioning and support are offered to the back and spline of the user.

When the user leans against the elastic support sheet, the bottom petals provide support to the lumbar part of the user, which typically requires sufficient support for comfortable leaning. Therefore, configuring the dimension D₂ along the vertical direction of the bottom petals to be smaller reduces the deformation of the cantilever structure formed by the bottom petals, that is, enabling the lower petals to provide stronger support.

In some embodiments of the present disclosure, with respect to the four-petal-shaped elastic support sheet 140, the number of elastic support rods is specifically designed. Referring to FIG. 4 again and further referring to FIG. 8, the back structure of the elastic support sheet and the elastic support rods is illustrated. As illustrated in FIG. 4 and FIG. 8, at least three elastic support rods 130 are arranged. At least two of the elastic support rods are connected between the back faces of the left and right petals in the elastic support sheet 140 and the middle section of the elastic support member 120. At least one of the elastic support rods 130 is connected between the back face of the top petal in the elastic support sheet 140 and the middle section of the elastic support member 120.

As described above, when the user leans against the elastic support sheet, the top petal is subjected to a greater force applied by the spinal part of the user, and thus sufficient support is required. The left-side and right-side petals mainly provide support to two sides of the back of the user, and likewise substantial support is required. The bottom petal primarily supports the lumbar part of the user, and are thus suffers a smaller force from leaning. Based on this, in order to reduce production costs while ensuring the structural stability of the elastic support sheet 140 and providing comfortable leaning support, at least three elastic support rods 130 are abutted against the top petal and the left and right petals to support the elastic support sheet 140.

For the embodiment where the dimension D₁ along the vertical direction of the top petal is set to be greater than the dimension D₂ along the vertical direction of the bottom petal, and three elastic support rods 130 are arranged, the dimension D₂ along the vertical direction of the bottom petal has been minimized, and therefore, when a force is applied, the elastic deformation of the bottom petals is small, such that reliable support is provided to the lumbar part of the user. Where an additional elastic support rod 130 is arranged on the back face of the bottom petal, the bottom petals may be subjected to extremely limited deformation under a force, and consequently the bottom petals fail to better conform to the lumbar part of the user, which may lead to discomfort.

Considering that different users may have varying requirements for cushioning and support, to accommodate the needs of more users, the present disclosure also designs an adjustable tension mechanism for the back support assembly. For more details, reference may be made to FIGS. 9 and 10. FIG. 9 illustrates the structure of the back support assembly without the elastic support sheet and the elastic support rods, and FIG. 10 illustrates a cross-sectional view of the side of the back support assembly. As illustrated in FIG. 10, the connection portion 111 includes a first connection portion 1111 and a second connection portion 1112. A first end 1201 of the elastic support member 120 is rotatably connected to the first connection portion 1111, and a second end 1202 of the elastic support member 120 is slidably connected to the second connection portion 1112 along an extension direction of the elastic support member 120 (the direction indicated by a double-headed arrow A in FIG. 10). The second end 1202 of the elastic support member 120 is configured to adjust the elasticity of the elastic support member 120 when sliding relative to the second connection portion 1112.

Specifically, a manual or motorized adjustment mechanism, such as a push rod, a threaded rod, a motor, a hydraulic or pneumatic cylinder, or the like may be arranged on the second connection portion 1112. This adjustment mechanism drives the second end 1202 of the elastic support member 120 to slide, thereby achieving adjustment of the elasticity of the elastic support member 120.

As illustrated in FIG. 10, in the case that the second end 1202 of the elastic support member 120 slides in a direction indicated by an upper left arrow of the double-headed arrow A, the first end 1201 of the elastic support member 120 rotates relative to the first connection portion 1111, and the middle section of the elastic support member 120 continues to protrude forward. In other words, the middle section of the elastic support member 120 protrudes to the left and its bending degree increases. In this case, the elasticity of the elastic support member 120 increases, such that greater support is provided to the back of the user. Conversely, in the case that the second end 1202 of the elastic support member 120 slides in the direction indicated by a lower right arrow of the double-headed arrow A, the first end 1201 of the elastic support member 120 rotates relative to the first connection portion 1111, and the middle section of the elastic support member 120 moves backward. In other words, the middle section of the elastic support member 120 moves to the right and its bending degree decreases. In this way, the elasticity of the elastic support member 120 decreases, such that the back support force provided to the user is correspondingly reduced.

To facilitate the adjustment of the back support force, the present disclosure further proposes an embodiment. For details, reference may be made to FIGS. 9 and 10. As illustrated in the FIGS. 9 and 10, a mounting slot 11121 is defined in the second connection portion 1112, and the second end 1202 of the elastic support member 120 extends into the mounting slot 11121 and is slidable within the mounting slot 11121. An adjustment screw 1113 is rotatably arranged within the mounting slot 11121. One end of the adjustment screw 1113 is threadedly connected to the second end 1202, extending into the mounting slot 11121, of the elastic support member 120. A knob 1114 is arranged at the other end of the adjustment screw 1113. An opening 11122 is defined in a wall of the mounting slot 11121, and a portion of the knob 1114 extends out of the opening 11122. The portion of the knob 1114 extending out of the opening 11122 is configured to receive a force and rotate to drive the adjustment screw 1113 to rotate, such that the second end 1202 of the elastic support member 120 is driven to slide in the mounting slot 11121 to adjust the elastic force of the elastic support member 120.

By arranging the mounting slot 11121 and allowing the second end 1202 of the elastic support member 120 to extend into the mounting slot 11121, an inner wall of the mounting slot 11121 is capable of guiding and limiting sliding of the second end 1202. The configuration where threaded engagement between the adjustment screw 1113 and the second end 1202 is employed to drive the sliding motion of the second end 1202 allows for easy and effortless adjustment. By defining an opening 11122 in the wall of the mounting slot 11121 to accommodate a protrusion portion of the knob 1114 on the adjustment screw 1113, users may conveniently apply a force to the protrusion portion of the knob 1114 through the opening 11122 with their hands, such that the adjustment screw 1113 is driven to rotate and the elasticity of the elastic support member 120 is adjusted.

To ensure that the sliding direction of the second end 1202 of the elastic support member 120 is accurate and reliable to ensure effective adjustment of the elasticity of the elastic support member 120, the present disclosure further proposes an embodiment. For details, reference may be made to FIG. 11. FIG. 11 illustrates he structure of the second end of the elastic support member in cooperation with the mounting slot. As illustrated in FIG. 11, a limiting post 11123 is arranged within the mounting slot 11121, and a guiding hole 12021 is defined in the second end 1202. The limiting post 11123 and the guiding hole 12021 are slidably engaged to guide and limit sliding of the second end 1202.

According to another aspect of the embodiments of the present disclosure, a chair 300 is provided. As illustrated in FIG. 12, the chair 300 includes the support force adjustment assembly 100 as described in any one of the above embodiments. Specifically, a main body of the chair 300 may include a chassis. The bottom end of the back support frame of the back support assembly is securely connected to the chassis, such that the back support assembly is assembled and secured to the main body of the chair.

It should be finally noted that the above-described embodiments are merely for illustration of the present disclosure, but are not intended to limit the present disclosure. Although the present disclosure is described in detail with reference to these embodiments, a person skilled in the art may also make various modifications to the technical solutions disclosed in the embodiments, or make equivalent replacements to a part of or all technical features contained therein. Such modifications or replacement, made without departing from the principles of the present disclosure, shall fall within the scope of the present disclosure. Especially, various technical features mentioned in various embodiments may be combined in any fashion as long as there is no structural conflict.