Waist rest and seat thereof

Abstract

The utility model relates to the technical field of seats, in particular to a waist rest and a seat thereof. A waist rest comprises a waist rest body, a clamping seat is formed on the waist rest body, an elastic shaft is arranged on the clamping seat in a penetrating mode, the output ends at the two ends of the elastic shaft extend out of the outer side of the clamping seat, and at least one output end can elastically stretch out and draw back relative to the clamping seat in the axial direction of the elastic shaft. According to the technical scheme, the elastic shaft is arranged on the clamping seat of the waist rest body, and at least one output end of the elastic shaft can elastically stretch out and draw back relative to the clamping seat, so that the output end can be quickly assembled with an external groove or hole, and the assembling convenience is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of seats, in particular to a lumbar support and a seat thereof. Background Art

[0002] For the convenience of transportation, the existing seats usually disassemble the backrest, lumbar support, etc. and put them into a transport box, which is then assembled after being transported to a designated location. The existing lumbar support is fixed by bolts or screws, which is cumbersome to assemble; it is also fixed by buckles or fixing clips, but the assembly reliability is poor. Summary of the invention

[0003] In order to solve the above problems, the first purpose of the utility model is to provide a lumbar support. By arranging an elastic shaft on the lumbar support, the output end of the elastic shaft can be elastically extended and retracted, and can be quickly assembled with an external groove or hole, thereby greatly improving the convenience of assembly and improving user experience. In addition, through the connection structure between the shaft and the groove or the shaft and the hole, the assembly reliability is good. The second purpose of the utility model is to provide a seat having the above-mentioned lumbar support.

[0004] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0005] A lumbar support, comprising a lumbar support body, characterized in that: a holder is formed on the lumbar support body, an elastic shaft is passed through the holder, output ends at both ends of the elastic shaft extend out of the outside of the holder, and at least one output end can be elastically extended relative to the holder along the axial direction of the elastic shaft. In this technical solution, an elastic shaft is provided on the holder of the lumbar support body, and at least one output end of the elastic shaft can be elastically extended relative to the holder, so that the output end can be quickly assembled with an external groove or hole, greatly improving the convenience of assembly.

[0006] Preferably, an assembly slope is constructed on the end of the axially retractable output end of the elastic shaft; when radial force is applied to the assembly slope, the output end of the elastic shaft can be driven to axially retract. In this technical solution, the assembly slope can cooperate with the outside at a certain angle, and the action angle is wider, so that it is more convenient for the output end to contact with the outside to achieve axial retraction of the output end, further improving the convenience of assembly.

[0007] Preferably, the elastic shaft includes two groups of axial elastic components arranged on the base in the axial direction of the elastic shaft facing away from each other, and the output end of the axial elastic component is elastically retractable relative to the base. In this technical solution, the two ends of the elastic shaft are two groups of axial elastic components, so both ends of the elastic shaft can be quickly assembled, which is more convenient. It should be noted here that if only one end of the elastic shaft is elastically retractable, the end that cannot be elastically retractable is first inserted into the groove or hole, and then the elastic shaft is swung to insert the elastically retractable end into the groove or hole, similar to the installation method of a battery.

[0008] Preferably, the axial elastic component comprises a clamping shaft and a first spring, the first spring is positioned inside the clamping seat and supported on the clamping shaft, and the clamping shaft serves as an output end of the axial elastic component;

[0009] An abutment groove is constructed on the inner side of the clamping shaft, and the inner end edge of the clamping shaft extends outward to form a first limiting ring; a fixing plate is provided on the inner side of the clamping seat, and a fixing shaft is provided on the fixing plate along the length direction of the elastic shaft; one end of the first spring abuts in the abutment groove, and the other end is sleeved on the outside of the fixed shaft and abuts on the fixing plate, and the first limiting ring abuts on the inner wall of the clamping seat.

[0010] In the above technical solution, the clamping shaft as the output end of the axial elastic component is axially retracted relative to the clamping seat, and the elastic force is provided by the first spring. The first limiting ring can prevent the clamping shaft from popping out of the clamping seat and play an axial limiting role. The setting of the fixed shaft is used to locate the inner end of the first spring to prevent the inner end of the first spring from moving radially.

[0011] Preferably, the base includes a mounting seat and a back plate, the inner wall of the back plate is provided with a plurality of buckles, the mounting seat is provided with a clamping hole or a clamping groove, and the plurality of buckles are connected with the clamping hole or the clamping groove by a clamping connection; a first positioning port is constructed on the side of the first limiting ring facing the lumbar support body, and a clamping plate that cooperates with the first positioning port is provided on both sides of the fixing plate and along the length direction of the elastic axis in the mounting seat; a second positioning port is provided on the first limiting ring and the fixing plate correspondingly facing the backrest, and a clamping strip that cooperates with the second positioning port is provided on the inner wall of the back plate along the length direction of the elastic axis. In this technical solution, the mounting seat and the back plate are connected by a clamping connection, specifically, the upper part cooperates with the two buckles through two buckles, and the lower part cooperates with the two clamping grooves through two buckles. The first positioning port of the first limiting ring is clamped with the clamping plate in the mounting seat to prevent the first limiting ring from rotating and improve the axial movement stability of the clamping shaft. The clamping strip on the back plate and the second positioning hole can not only further prevent the first limit ring from rotating, but also improve the assembly strength of the back plate and the installation to prevent the two from moving relative to each other longitudinally.

[0012] Preferably, the two output ends of the elastic shaft are constructed as rotating shafts, and an elastic support component is provided on the back of the card holder below the elastic shaft, and the outer end of the elastic support component extends out of the rear end surface of the card holder and can be elastically retracted. In this technical solution, the elastic shaft acts as a rotating shaft and cooperates with the elastic support component to play an elastic support role. The human body acts on the waist to rotate the rotating shaft to a certain angle, and the elastic support component is elastically supported on the outside to play a supporting, buffering and protective role, making the user more comfortable when using it.

[0013] Preferably, the outer end surface of the card seat protrudes outward to form a pasting block and forms a fitting groove on the inner side of the card seat, and the elastic support assembly includes a cylinder, a second spring and a butt joint. The cylinder is arranged in the fitting groove, and the second spring is sleeved on the cylinder and one end abuts in the fitting groove, and the other end abuts in the butt joint. The inner end edge of the butt joint forms a second limiting ring. A through hole is opened on the back of the card seat, and the butt joint extends out of the through hole. A gasket is provided at the bottom of the fitting groove. In this technical solution, the cylinder prevents the inner end of the second spring from moving radially; the second limiting ring prevents the butt joint from detaching from the card seat, and plays a limiting role.

[0014] A chair, including a backrest, characterized in that it also includes a lumbar support as described above, wherein a mounting plate is formed on the backrest, two relatively arranged slots are constructed on the mounting plate, and at least one end of the elastic shaft is elastically connected to the slot. In this technical solution, two slots are constructed on the mounting plate of the backrest, and at least one end of the elastic shaft is elastically connected to the slot, so that the assembly of the elastic shaft and the slot can be quickly realized, thereby facilitating the assembly of the lumbar support and the backrest.

[0015] A chair, comprising a backrest, characterized in that: it also comprises a lumbar support as described in any one of the second to fifth, sixth or seventh items above, the backrest is formed with an assembly plate, the assembly plate is constructed with two oppositely arranged slots, and at least one end of the elastic shaft is elastically engaged with the slot;

[0016] A guide cut surface matching the assembly bevel is arranged in the insertion direction of the slot; when the lumbar support body is installed on the assembly plate, the guide cut surface can drive the output end of the elastic shaft to axially extend and retract when the reaction force of the guide cut surface is on the assembly bevel.

[0017] In the above technical solution, two slots are constructed on the assembly plate of the backrest, at least one end of the elastic shaft is elastically connected to the slot, and a guide section is arranged in the insertion direction of the slot. The assembly inclined surface on the elastic shaft cooperates with the guide section, which can further improve the assembly speed, enable the elastic telescopic end to be inserted into the slot faster and avoid wear of the end.

[0018] A chair, comprising a backrest, characterized in that: it also comprises a lumbar support as described in the sixth or seventh item above, the backrest is formed with a mounting plate, the mounting plate is constructed with two protrusions, the two protrusions are constructed with two oppositely arranged slots, at least one end of the elastic shaft is elastically clamped on the slot and can rotate relative to the slot, and the outer end of the elastic support component is elastically supported on the mounting plate;

[0019] The assembly plate is provided with an arc-shaped rotating groove between the protrusions, the rear end surface of the clamping seat is formed with an arc-shaped convex wall matched with the arc-shaped rotating groove, and the bottom surface of the arc-shaped rotating groove is provided with an abutment strip abutting with the arc-shaped convex wall.

[0020] In the above technical solution, two protrusions are provided on the assembly plate of the backrest, and two slots are constructed on the two protrusions. At least one end of the elastic shaft is elastically connected to the slot, so that the elastic shaft and the slot can be assembled quickly and can rotate relative to the slot. The elastic shaft rotates a certain angle on the waist of the human body, and the elastic support component is elastically supported on the assembly plate, which plays a role of support, buffering and protection, making the user more comfortable when using it. The setting of the arc-shaped rotation slot is convenient for cooperation with the card seat, making the card seat more stable during the linkage process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the assembly diagram of the backrest and lumbar support.

[0022] Figure 2 Schematic diagram of the construction of the card slot on the assembly board.

[0023] Figure 3 It is a schematic diagram of the three-dimensional structure of the lumbar support.

[0024] Figure 4 It is a schematic diagram of the assembly of the elastic shaft, elastic support component and mounting seat.

[0025] Figure 5 A schematic diagram of the three-dimensional structure of the back panel.

[0026] Figure 6 It is a schematic diagram of the three-dimensional structure of the mounting base.

[0027] Figure 7 It is a schematic diagram of the three-dimensional structure of the axial elastic component. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more, unless otherwise clearly defined.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. Embodiment 1:

[0033] like Figures 3 to 7 A lumbar support is shown, comprising a lumbar support body, a base 1 is formed on the lumbar support body, an elastic shaft 2 is passed through the base 1, output ends at both ends of the elastic shaft 2 extend out of the outside of the base 1, and at least one output end can be elastically extended relative to the base 1 along the axial direction of the elastic shaft 2. In this technical solution, an elastic shaft is provided on the base of the lumbar support body, and at least one output end of the elastic shaft can be elastically extended relative to the base, so the output end can be quickly assembled with an external groove or hole, greatly improving the convenience of assembly.

[0034] Furthermore, an assembly slope 3 is constructed on the end of the axially retractable output end of the elastic shaft 2; when radial force is applied to the assembly slope 3, the output end of the elastic shaft 2 can be driven to axially retract. In this technical solution, the assembly slope can cooperate with the outside at a certain angle, and the action angle is wider, so that it is more convenient for the output end to contact with the outside to achieve axial retraction of the output end, and the assembly convenience is further improved.

[0035] Furthermore, the elastic shaft 2 includes two groups of axial elastic components arranged on the card holder 1 in the axial direction of the elastic shaft 2 and facing away from each other, and the output end of the axial elastic component is elastically retractable relative to the card holder 1. In this technical solution, the two ends of the elastic shaft are two groups of axial elastic components, so both ends of the elastic shaft can be quickly assembled, which is more convenient. It should be noted here that if only one end of the elastic shaft is elastically retractable, the end that cannot be elastically retractable is first inserted into the groove or hole, and then the elastic shaft is swung to insert the elastically retractable end into the groove or hole, which is similar to the installation method of a battery.

[0036] Furthermore, the axial elastic component includes a clamping shaft 4 and a first spring 5. The first spring 5 is positioned inside the clamping seat 1 and supported on the clamping shaft 4. The clamping shaft 4 serves as the output end of the axial elastic component.

[0037] An abutment groove is constructed on the inner side of the clamping shaft 4, and the inner end edge of the clamping shaft 4 extends outward to form a first limiting ring 6; a fixing plate 7 is provided on the inner side of the clamping base 1, and a fixing shaft 8 is provided on the fixing plate 7 along the length direction of the elastic shaft 2; one end of the first spring 5 abuts in the abutment groove, and the other end is sleeved on the outside of the fixed shaft 8 and abuts on the fixing plate 7, and the first limiting ring 6 abuts on the inner wall of the clamping base 1.

[0038] In the above technical solution, the clamping shaft as the output end of the axial elastic component is axially retracted relative to the clamping seat, and the elastic force is provided by the first spring. The first limiting ring can prevent the clamping shaft from popping out of the clamping seat and play an axial limiting role. The setting of the fixed shaft is used to locate the inner end of the first spring to prevent the inner end of the first spring from moving radially.

[0039] Further, the clamping seat 1 includes a mounting seat 9 and a back plate 10, a plurality of buckles 11 are provided on the inner wall of the back plate 10, a clamping hole 12 or a clamping groove 13 is provided on the mounting seat 9, and the plurality of buckles 11 are connected by clamping with the clamping hole 12 or the clamping groove 13; a first positioning hole 14 is constructed on the first limiting ring 6 on the side facing the lumbar support body, and a clamping plate 15 is provided on both sides of the fixing plate 7 and along the length direction of the elastic shaft 2 in the mounting seat 9 to match the first positioning hole 14; a second positioning hole 16 is provided on the first limiting ring 6 and the fixing plate 7 on the side facing the backrest 100, and a clamping strip 17 is provided on the inner wall of the back plate 10 along the length direction of the elastic shaft 2 to match the second positioning hole 16. In this technical solution, the mounting seat and the back plate are connected by clamping, specifically, the upper part is matched with the two buckles through two buckles, and the lower part is matched with the two clamping grooves through two buckles. The first positioning opening of the first limiting ring is clamped with the clamping plate in the mounting seat to prevent the first limiting ring from rotating and improve the axial movement stability of the clamping shaft. The clamping strip on the back plate is clamped with the second positioning opening, which can not only further prevent the first limiting ring from rotating, but also improve the assembly strength of the back plate and the mounting to prevent the two from moving relative to each other longitudinally.

[0040] Furthermore, the two output ends of the elastic shaft 2 are constructed as rotating shafts, and an elastic support component is provided on the back of the card holder 1 below the elastic shaft 2, and the outer end of the elastic support component extends out of the rear end surface of the card holder 1 and can be elastically retracted. In this technical solution, the elastic shaft acts as a rotating shaft and cooperates with the elastic support component to play an elastic support role. The human body acts on the waist to rotate the rotating shaft to a certain angle, and the elastic support component is elastically supported on the outside to play a supporting, buffering and protective role, making the user more comfortable when using it.

[0041] Furthermore, the outer end surface of the card seat 1 protrudes outward to form a pasting block 18 and forms a fitting groove 19 on the inner side of the card seat 1. The elastic support assembly includes a cylinder 20, a second spring 21 and a butt joint 22. The cylinder 20 is arranged in the fitting groove 19. The second spring 21 is sleeved on the cylinder 20 and one end abuts in the fitting groove 19 and the other end abuts in the butt joint 22. The inner end edge of the butt joint 22 forms a second limiting ring 23. The back of the card seat 1 is provided with a through hole 24. The butt joint 22 extends out of the through hole 24. A washer 25 is provided at the bottom of the fitting groove 19. In this technical solution, the cylinder prevents the inner end of the second spring from moving radially; the second limiting ring prevents the butt joint from being detached from the card seat, and plays a limiting role. Embodiment 2:

[0042] like Figure 1~2 A seat shown in the figure comprises a backrest 100 and a lumbar support 200, wherein a mounting plate 26 is formed on the backrest 100, and two oppositely arranged slots 27 are constructed on the mounting plate 26, and at least one end of the elastic shaft 2 is elastically connected to the slot 27. In this technical solution, two slots are constructed on the mounting plate of the backrest, and at least one end of the elastic shaft is elastically connected to the slot, so that the assembly of the elastic shaft and the slot can be quickly realized, thereby facilitating the assembly of the lumbar support and the backrest. Embodiment three:

[0043] like Figure 1~2 A seat shown in the figure comprises a backrest 100 and a lumbar support 200, wherein the backrest 100 is formed with an assembly plate 26, and the assembly plate 26 is constructed with two oppositely arranged slots 27, and at least one end of the elastic shaft 2 is elastically engaged with the slot 27;

[0044] A guide cut surface 28 cooperating with the assembly bevel 3 is provided in the insertion direction of the slot 27; when the lumbar support body is installed on the assembly plate 26, the guide cut surface 28 reacts to the assembly bevel 3 to drive the output end of the elastic shaft 2 to axially extend and retract.

[0045] In the above technical solution, two slots are constructed on the assembly plate of the backrest, at least one end of the elastic shaft is elastically connected to the slot, and a guide section is arranged in the insertion direction of the slot. The assembly inclined surface on the elastic shaft cooperates with the guide section, which can further improve the assembly speed, enable the elastic telescopic end to be inserted into the slot faster and avoid wear of the end. Embodiment 4:

[0046] like Figure 1~2 A seat shown in the figure comprises a backrest 100 and a lumbar support 200, wherein the backrest 100 is formed with an assembly plate 26, the assembly plate 26 is formed with two protrusions 29, the two protrusions 29 are formed with two oppositely arranged slots 27, at least one end of the elastic shaft 2 is elastically engaged with the slot 27 and can rotate relative to the slot 27, and the outer end of the elastic support assembly is elastically supported on the assembly plate 26;

[0047] The assembly plate 26 is provided with an arc-shaped rotating groove 30 between the protrusions 29 , the rear end surface of the holder 1 is formed with an arc-shaped convex wall 31 cooperating with the arc-shaped rotating groove 30 , and the bottom surface of the arc-shaped rotating groove 30 is provided with an abutment strip 32 abutting with the arc-shaped convex wall 31 .

[0048] In the above technical solution, two protrusions are provided on the assembly plate of the backrest, and two slots are constructed on the two protrusions. At least one end of the elastic shaft is elastically connected to the slot, so that the elastic shaft and the slot can be assembled quickly and can rotate relative to the slot. The elastic shaft rotates a certain angle on the waist of the human body, and the elastic support component is elastically supported on the assembly plate, which plays a role of support, buffering and protection, making the user more comfortable when using it. The setting of the arc-shaped rotation slot is convenient for cooperation with the card seat, making the card seat more stable during the linkage process.

[0049] In this specific embodiment, in view of the inconvenience of assembling the lumbar support in the existing chair, the above scheme is to set an elastic shaft on the base of the lumbar support, and the elastic shaft has an output end that can be elastically extended relative to the base, so that the output end can be quickly assembled with the external groove or hole, greatly improving the convenience of assembly. In addition, the assembly bevel on the elastic shaft cooperates with the guide section, which can further improve the assembly speed. In addition, the elastic shaft can also rotate as a rotating shaft. When the human body acts on the lumbar support, the elastic shaft rotates a certain angle, and the elastic support component elastically supports the backrest, which plays a role of support, buffering and protection, making the user more comfortable when using it.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0051] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A lumbar support, comprising a lumbar support body, characterized in that: A base (1) is formed on the lumbar support body, and an elastic shaft (2) is passed through the base (1). Output ends at both ends of the elastic shaft (2) extend out of the base (1), and at least one output end can elastically expand and contract relative to the base (1) along the axial direction of the elastic shaft (2).

2. A lumbar support according to claim 1, characterized in that: An assembly bevel (3) is constructed on the end of the axially retractable output end of the elastic shaft (2); when radial force is applied to the assembly bevel (3), the output end of the elastic shaft (2) can be driven to axially retract.

3. A lumbar support according to claim 2, characterized in that: The elastic shaft (2) comprises two groups of axial elastic components which are arranged on the base (1) in a direction opposite to the axial direction of the elastic shaft (2), and the output ends of the axial elastic components are elastically retractable relative to the base (1).

4. A lumbar support according to claim 3, characterized in that: The axial elastic component comprises a clamping shaft (4) and a first spring (5), wherein the first spring (5) is positioned inside the clamping seat (1) and supported on the clamping shaft (4), and the clamping shaft (4) serves as an output end of the axial elastic component; An abutment groove is constructed on the inner side of the clamping shaft (4), and the inner end edge of the clamping shaft (4) extends outward to form a first limiting ring (6); a fixing plate (7) is provided on the inner side of the clamping seat (1), and a fixing shaft (8) is provided on the fixing plate (7) along the length direction of the elastic shaft (2); one end of the first spring (5) abuts in the abutment groove, and the other end is sleeved on the outside of the fixing shaft (8) and abuts on the fixing plate (7), and the first limiting ring (6) abuts on the inner wall of the clamping seat (1).

5. A lumbar support according to claim 4, characterized in that: The clamping seat (1) comprises a mounting seat (9) and a back plate (10); a plurality of buckles (11) are provided on the inner wall of the back plate (10); a clamping hole (12) or a clamping groove (13) is provided on the mounting seat (9); the plurality of buckles (11) are clamped and connected with the clamping hole (12) or the clamping groove (13); a first positioning opening (14) is constructed on the first limiting ring (6) on the side facing the lumbar support body; a clamping plate (15) matching the first positioning opening (14) is provided on both sides of the fixing plate (7) and along the length direction of the elastic axis (2) in the mounting seat (9); a second positioning opening (16) is correspondingly provided on the first limiting ring (6) and the fixing plate (7) on the side facing the backrest (100); a clamping strip (17) matching the second positioning opening (16) is provided on the inner wall of the back plate (10) along the length direction of the elastic axis (2).

6. A lumbar support according to claim 2 or 3, characterized in that: The output ends at both ends of the elastic shaft (2) are constructed as rotating shafts, and the back of the card seat (1) is located below the elastic shaft (2) and is provided with an elastic support component, the outer end of the elastic support component extends out of the rear end surface of the card seat (1) and is elastically retractable.

7. A lumbar support according to claim 6, characterized in that: The outer end surface of the card seat (1) protrudes outward to form a pasting block (18) and a fitting groove (19) is formed on the inner side of the card seat (1). The elastic support component comprises a cylinder (20), a second spring (21) and a butt joint (22). The cylinder (20) is arranged in the fitting groove (19). The second spring (21) is sleeved on the cylinder (20) and one end of the second spring abuts in the fitting groove (19) and the other end abuts in the butt joint (22). The inner end edge of the butt joint (22) forms a second limiting ring (23). A through hole (24) is opened on the back of the card seat (1). The butt joint (22) protrudes from the through hole (24). A gasket (25) is provided at the bottom of the fitting groove (19).

8. A chair, comprising a backrest (100), characterized in that: It also comprises a lumbar support as claimed in any one of claims 1 to 7, wherein a mounting plate (26) is formed on the backrest (100), two oppositely arranged slots (27) are constructed on the mounting plate (26), and at least one end of the elastic shaft (2) is elastically connected to the slot (27).

9. A chair, comprising a backrest (100), characterized in that: Also comprising a lumbar support as claimed in any one of claims 2 to 5, 6 or 7, wherein the backrest (100) is formed with a mounting plate (26), the mounting plate (26) is formed with two oppositely arranged slots (27), and at least one end of the elastic shaft (2) is elastically connected to the slot (27); A guide cut surface (28) cooperating with the assembly bevel (3) is provided in the insertion direction of the slot (27); when the lumbar support body is mounted on the assembly plate (26), the guide cut surface (28) can drive the output end of the elastic shaft (2) to axially extend and retract when the reaction force of the guide cut surface (28) acts on the assembly bevel (3).

10. A chair, comprising a backrest (100), characterized in that: Also comprising a lumbar support as claimed in claim 6 or 7, wherein a mounting plate (26) is formed on the backrest (100), two protrusions (29) are constructed on the mounting plate (26), two oppositely arranged slots (27) are constructed on the two protrusions (29), at least one end of the elastic shaft (2) is elastically clamped on the slot (27) and can rotate relative to the slot (27), and the outer end of the elastic support component is elastically supported on the mounting plate (26); An arc-shaped rotating groove (30) is provided on the assembly plate (26) between the protrusions (29); an arc-shaped convex wall (31) cooperating with the arc-shaped rotating groove (30) is formed on the rear end surface of the holder (1); and an abutment strip (32) abutting with the arc-shaped convex wall (31) is provided on the bottom surface of the arc-shaped rotating groove (30).

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