Lumbar and back linkage mechanism and seat

Abstract

The utility model provides a waist-back linkage mechanism and a seat. The waist-back linkage mechanism comprises a chair seat for supporting buttocks, a chair back assembly for supporting the back and a waist rest for supporting the waist, the chair back assembly and the waist rest are rotationally arranged relative to the chair seat, and the waist rest is also rotationally connected with the chair back assembly; the mechanism has a vertical state and an inclined state, and in the vertical state, the chair back assembly and the waist rest support the waist and the back forwards; in the inclined state, the chair back assembly and the waist rest are inclined, and the waist rest faces upwards for a human body to lie down; when the chair is switched from the vertical state to the inclined state, the chair back assembly drives the waist rest to move, and the included angle between the waist rest and the chair back assembly is reduced to change the relative posture of the waist rest and the chair back assembly, so that the chair adapts to the waist and back of a human body when the human body sits and lies; in the vertical state, the chair back assembly and the waist rest can be attached to the approximately S-shaped human body waist and back curve, in the inclined state, the included angle between the waist rest and the chair back assembly is reduced, the chair back assembly can be attached to the approximately linear human body waist and back curve when the human body leans backwards, and a better comfortable sitting and lying feeling is provided.

Description

Technical Field

[0001] The utility model relates to the field of furniture, in particular to a waist and back linkage mechanism and a seat. Background Art

[0002] There are many categories of existing traditional seats. Many manufacturers focus on the field of office chairs. Focusing on ergonomics and improving comfort, the functions of office chairs are becoming more and more complete, such as seat adjustment, armrest adjustment, headrest adjustment, and chair back component adjustment, etc., all of which are to allow users to have a sitting posture that suits them and get a comfortable sitting experience.

[0003] Considering the situation and environment in which the office chair is used, most office chairs have the function of switching between sitting and lying positions. The purpose is to allow users to sit normally when working, and lie down to rest when tired. There are also many ergonomic considerations:

[0004] In a sitting state, the human waist and back curve is S-shaped, and the lumbar support in the chair back will bulge forward to fit the S-shaped waist and back curve, while in a lying state, the human waist and back curve is roughly straight. Traditional single-back and double-back chairs cannot achieve the switching of the chair back support surface curve when switching between sitting and lying positions, and the user cannot relax in a lying state; and even some double-back chairs designed for this point cannot continuously and completely support the entire waist and back of the human body in a lying state, thereby reducing comfort, such as Chinese utility model patent CN201120067855.8. In the solution provided by this patent, when the chair back is reclined, it can conform to the human waist and back curve, that is, it switches from an S-shaped support curve to a straight line, but the chair back will make the user's waist empty and unable to get effective support, resulting in poor comfort and health risks in long-term use. Summary of the invention

[0005] In order to solve the above-mentioned technical problems, the utility model provides a waist-back linkage mechanism, including a chair seat for supporting the buttocks of a human body, a chair back assembly for supporting the back of a human body, and a waist support for supporting the waist of a human body; the chair back assembly and the waist support are both rotatably arranged relative to the chair seat, and the waist support is also rotatably connected to the chair back assembly; the mechanism has an upright state and an inclined state, in the upright state, the chair back assembly and the waist support support the waist and back of the human body forward for the human body to sit normally; in the inclined state, the chair back assembly and the waist support are inclined, and the waist support faces upward for the human body to lie down; when switching from the upright state to the inclined state, the chair back assembly drives the waist support to move, and the angle between the waist support and the chair back assembly is reduced; in the upright state, the chair back assembly and the waist support can support the waist and back of the human body, and fit the roughly S-shaped waist and back curve of the human body, in the inclined state, the angle between the waist support and the chair back assembly is reduced, the curved surface formed by the two changes, and can fit the roughly straight waist and back curve when the human body leans back, providing a better comfortable sitting and lying feeling.

[0006] When the waist-back linkage mechanism switches from an upright state to a tilted state, when the chair back assembly leans back relative to the seat, the waist support rotates and also has a tendency to push forward relative to the chair back assembly, so as to enhance the support for the human waist and eliminate the feeling of empty waist.

[0007] A seat is further provided, including a chassis and the above-mentioned lumbar-back linkage mechanism, the seat is arranged on the chassis, the backrest assembly is rotatably connected to the chassis, and the backrest assembly and the chassis rotate to realize the rotation of the backrest assembly and the seat; the chassis provides more possibilities for the movement of the backrest assembly and the lumbar support, and the vertical movement of the seat can also enable the seat to have movement ability, thereby realizing the linkage among the three, and through the linkage among the backrest assembly, the lumbar support and the seat, it can further achieve targeted and effective support for various parts of the human body under different human postures, thereby improving the comfort of the seat.

[0008] The technical solution of the utility model is achieved in this way:

[0009] A waist-back linkage mechanism, comprising:

[0010] A seat configured to support a buttocks of a human body;

[0011] The backrest assembly is configured to support the back of a human body, and the backrest assembly and the seat are relatively rotatable;

[0012] The lumbar support is rotatably connected to the seat, the lumbar support is linked with the chair back assembly and the lumbar support and the chair back assembly are relatively rotatably arranged; the lumbar support is configured to support the waist of a human body;

[0013] The invention has an upright state and a tilted state. In the upright state, the chair back assembly and the lumbar support are vertical and both face forward, so that a human body can sit normally. In the tilted state, the chair back assembly leans back, and the lumbar support tilts and faces upward, so that a human body can lie down. When switching from the upright state to the tilted state, the chair back assembly rotates backward relative to the seat, and the lumbar support moves as the chair back assembly leans back, and the angle between the lumbar support and the chair back assembly decreases to change the relative posture of the lumbar support and the chair back assembly. The change in the relative posture of the lumbar support and the chair back assembly is configured to adapt to the waist and back of a human body when sitting or lying down.

[0014] As more and more seats have similar functions, the design focus and mainstream have gradually shifted from manual adjustment to linkage. Compared with adjustments that require manual operation, the linkage of the mechanism is more convenient, tends to be automated, and appears to be more intelligent. For different functions, it is also important to reasonably allocate and use manual adjustment and linkage. For example, the position adjustment of parts such as armrests can be done manually, while the chair back tilt switching discussed in the present invention can replace the additional operating actions in manual adjustment because the user will drive the chair back to move when lying down. Therefore, the use of linkage is more reasonable and simpler.

[0015] Furthermore, the chair back assembly is rotatably arranged relative to the seat, and the chair back assembly has a basic reclining function. The lumbar support is rotatably connected to the seat and the chair back assembly. When a human body leans on it, the chair back assembly can drive the lumbar support to rotate relative to the seat, thereby realizing the switching of the mechanism between an upright state and a tilted state. Since the lumbar support is directly or indirectly rotatably connected to the seat, the lumbar support and the seat will not produce relative displacement movement in the front-to-back direction. A part of the lumbar support is always located above the seat. Therefore, in the front-to-back direction, the lower end of the lumbar support will not move backward beyond the rear end of the seat, so that there will be no gap between the seat and the lumbar support in the front-to-back direction, and the human body's waist and back can be fully and continuously supported, so that the waist can be reasonably and effectively supported without a feeling of empty waist.

[0016] In the upright state, the chair back assembly and the lumbar support can support the human body's waist and back, and fit the roughly S-shaped waist and back curve of the human body. In the tilted state, the angle between the lumbar support and the chair back assembly decreases, and the curved surface formed by the two changes, and can fit the roughly straight waist and back curve when the human body leans back. Therefore, when the human body sits or lies normally, the curved surfaces formed by the lumbar support and the chair back assembly conform to the ergonomics in their respective states, so as to provide a better comfortable sitting and lying feeling.

[0017] Preferably, the backrest assembly and the lumbar support form a supporting surface that fits the waist and back of the human body. The supporting surface has a reference line, which is located in the middle of the supporting surface in the left-right direction, and is a line connecting the upper end of the backrest assembly to the lower end of the lumbar support on the supporting surface; in the upright state, the reference line is an S-shaped curve with a convex lower part, and in the inclined state, the reference line is roughly a straight line. The reference line reflects the overall state of the supporting surface. In the upright state, the reference line is an S-shaped curve with a convex lower part, that is, in the upright state, the lumbar support protrudes forward relative to the backrest assembly, and is used to press forward against the human waist to fit the S-shaped waist and back curve of the human body when sitting normally; in the inclined state, the reference line is roughly a straight line, that is, in the inclined state, the angle between the lumbar support and the backrest assembly is reduced, and the shape of the supporting surface is changed to fit the straight waist and back curve of the human body when lying down.

[0018] Preferably, the seat is formed with a seat surface that fits the buttocks of a human body, and when switching from an upright state to a tilted state, the supporting surface and the seat surface are close to each other. When switching from the upright state to the tilted state, the supporting surface and the seat surface are close to each other, which means that when switching from the upright state to the tilted state, the lumbar support rotates, and its lower end is close to the seat, unlike a conventional seat where the lumbar support is far away from the seat, so that the lumbar support and the seat will not separate to form a gap, thereby preventing the waist from being empty when the human body lies down.

[0019] As a preferred embodiment, in the upright state and the inclined state, the front end of the lumbar support is always located above the seat; the supporting surface and the seat surface form a continuous fitting surface, and the fitting surface fits the buttocks, waist and back of the human body. The front end of the lumbar support is always located above the seat, and there will be no gap between the lumbar support and the seat due to leaning back, so the fitting surface is continuous rather than disconnected, so that the buttocks, waist and back of the human body can all be attached to the fitting surface, and the buttocks and waist and back of the human body can be effectively and reasonably supported without the situation of an empty waist.

[0020] Preferably, when switching from the upright state to the tilted state, the rotation angle of the lumbar support is greater than the rotation angle of the backrest assembly. The rotation angle of the lumbar support is greater than the rotation angle of the backrest assembly, so that the angle between the lumbar support and the backrest assembly can be reduced; the reason why the rotation angle of the lumbar support is greater than the rotation angle of the backrest assembly is that the rotation connection points of the lumbar support and the backrest assembly are different, the backrest assembly is rotationally connected to the chassis, and the lumbar support is rotationally connected to the rotating frame on the seat.

[0021] Preferably, in the tilted state, the tilt angle of the lumbar support relative to the ground is 13-20 degrees. The tilt angle of the lumbar support of the mechanism relative to the ground in the tilted state is significantly smaller than the tilt angle of the lumbar support in the existing chair, so that the tilt angle of the lumbar support of the mechanism relative to the vertical plane is larger, and its orientation is closer to upward to support the waist of the human body.

[0022] Preferably, in the upright state, the angle between the lumbar support and the seat is 115-120°, and in the inclined state, the angle between the lumbar support and the seat is 158-165°. When the lumbar support changes from the upright state to the inclined state, the angle between the lumbar support and the seat increases. In the upright state, the angle between the lumbar support and the seat is similar to that of a conventional seat, but in the inclined state, the angle between the lumbar support and the seat is significantly larger, the lumbar support is more inclined, and the direction of the lumbar support tends to be upward, so that the support for the human waist is more reasonable, and the user can get a more comfortable experience.

[0023] Preferably, the rotation angle of the lumbar support is 43-50°. The rotation angle of the lumbar support of the mechanism is larger than that of the existing seat lumbar support, the purpose of which is to make the lumbar support more inclined and more reasonably oriented, support the human waist in a better posture, and improve comfort.

[0024] A waist-back linkage mechanism comprises a seat, a seat back assembly and a waist support, wherein the waist-back and the seat are arranged to rotate relative to each other, the waist support is rotationally connected to the seat, and the waist support is linked with the seat back assembly and relatively rotated; the waist-back linkage mechanism has an upright state for supporting a human body to sit normally and an inclined state for supporting a human body to lie down, when switching from the upright state to the inclined state, the seat back assembly leans back relative to the seat, the waist support rotates with the seat back assembly relative to the seat, and at the same time the waist support rotates relative to the seat back assembly so that the waist support is pushed forward relative to the seat back assembly.

[0025] In the above technical solution, since the lumbar support is rotatably connected to the seat, the lumbar support and the backrest assembly are also relatively rotatably arranged. When the backrest assembly reclines, the lumbar support rotates relative to both the backrest assembly and the seat. Unlike the prior art, the lumbar support is not connected to the backrest assembly to form the same rotation as the seat with the backrest assembly, but rotates independently with the backrest assembly relative to the seat. Therefore, while the lumbar support and the seat rotate relative to each other, their rotation angles and positions relative to the seat are different. Therefore, for the reclining backrest assembly, the lumbar support rotatably connected to the seat has a tendency to move forward relatively. This tendency means that the upper part of the lumbar support is positioned further forward relative to the backrest behind it, that is, it is relatively forward to cater to the lumbar support of the human body, thereby enhancing the support of the lumbar support for the human waist and preventing the occurrence of an empty waist feeling.

[0026] Preferably, a moving part is provided between the backrest assembly and the lumbar support, and the backrest assembly and the lumbar support are relatively movable through the moving part; when the backrest assembly rotates backward relative to the seat, the lumbar support and the backrest assembly rotate relative to each other and the lumbar support and the backrest assembly move away from each other. A moving part is provided between the backrest assembly and the lumbar support to enable relative displacement of the two, so that the movement between the lumbar support, the backrest assembly and the seat can be smooth; in addition to providing a moving part between the backrest assembly and the lumbar support, a moving part can also be provided between the lumbar support and the seat, and the backrest assembly can also be connected to the chassis by rotation, and the chassis and the seat can move relative to each other to achieve the same function and effect.

[0027] Preferably, the moving part includes an extension seat and a sliding rotating part; the extension seat is fixedly connected to the chair back assembly, the sliding rotating part and the extension seat are slidably matched, and the lumbar support is rotatably connected to the sliding rotating part; when the chair back assembly rotates backward relative to the seat, the lumbar support and the sliding rotating part rotate and rotate relative to the chair back assembly, and at the same time, the sliding rotating part and the extension seat slide relative to each other, and the moving part extends. The moving part does not need to be operated, and it realizes adaptive changes with the movement of the chair back assembly and the lumbar support, so that the movement of the mechanism is smooth and smooth.

[0028] Preferably, one end of the sliding rotating member is rotatably connected to the upper end of the lumbar support, and a limiting column is provided at the other end of the sliding rotating member; a sliding groove is provided along the length direction of the extension seat, and the sliding rotating member is arranged in the sliding groove, and a limiting groove is provided on the extension seat beside the sliding groove, and the limiting column is arranged in the limiting groove. The moving member is provided to adapt to the movement of the lumbar support, the backrest assembly and the seat, and the sliding rotating member in the moving member and the extension seat move adaptively with the movement of the three, and the limiting column moves in the sliding groove to limit the movement trajectory of the sliding rotating member. At the same time, the moving member and the lumbar support limit the movement trajectory of both parties to achieve the preset movement mode of the mechanism.

[0029] Preferably, in the upright state, the extension seat bends downward from front to back. The shape of the extension seat not only adapts to the movement of the waist support but also limits the movement track of the sliding rotating member.

[0030] Preferably, the moving part is a connecting rod assembly, and the connecting rod assembly is configured to make the lumbar support and the chair back assembly relatively rotate and move relative to each other. When the moving part is a connecting rod assembly, the above functions can also be achieved.

[0031] Preferably, the moving part is a telescopic sleeve assembly, one end of which is relatively fixedly connected to the chair back assembly, and the other end of which is rotatably connected to the upper end of the waist support. When the moving part is a telescopic sleeve assembly, the above function can also be achieved.

[0032] Preferably, the moving part is an elastic body, the upper end of the lumbar support is hinged to the elastic body, and the elastic body is configured to deform when the lumbar support and the chair back assembly move relative to each other. When the moving part is an elastic body, the above function can also be achieved.

[0033] Preferably, a rotating frame is provided on the seat, the rotating frame is relatively fixed to the seat, the rotating frame is located at the rear of the seat, and the rotating frame extends upward and is rotatably connected to the lumbar support. The lumbar support is connected to the rotating frame instead of being directly connected to the seat. On the one hand, the height of the lumbar support is raised, so that the lumbar support has a height similar to that of the existing seat in an upright state, achieving the desired function. At the same time, the lumbar support will not interfere with the seat when rotating, and the seat can be effectively avoided. On the other hand, the lumbar support is rotatably connected to the rotating frame, which is obviously different from the rotation connection point of the backrest assembly. In this case, the lumbar support can be rotated at a larger angle, so that the angle between the lumbar support and the backrest assembly is reduced, achieving the desired effect.

[0034] Preferably, the rotating frame is rotatably connected to the waist support at the middle of the waist support. The lower end of the waist support is free and located below the rotation connection point between the waist support and the rotating frame. The lower end of the waist support can extend forward under the waist of the human body to provide support in a tilted state, so as to provide more comfortable waist support.

[0035] Preferably, the chair back assembly includes a backrest for resting against the human back and a back bracket connected below the backrest, the back bracket is rotatably arranged relative to the seat, the lower end of the chair back assembly is relatively fixedly connected to the upper end of the back bracket, and the upper end of the lumbar support is rotatably connected to the backrest or the back bracket.

[0036] A seat, comprising a chassis and a waist-back linkage mechanism as described above, wherein the seat is arranged on the chassis, and the backrest assembly is rotatably connected to the chassis. When the backrest assembly and the chassis rotate, the backrest assembly rotates relative to the seat, and the waist support also rotates relative to the backrest assembly and the seat. The seat is arranged on the chassis, and the backrest assembly is rotatably connected to the chassis. By adding the chassis to the seat, backrest assembly, and waist support of the above mechanism, the diversity of movement is achieved, that is, when the chassis is fixed as a base, the backrest assembly is rotatably connected to the chassis to achieve relative rotation with the seat. A movable connection can also be selectively set between the seat and the chassis, so that the backrest assembly and the seat move in the opposite direction, so that the waist support can have a larger rotation angle.

[0037] Preferably, the seat is arranged on the chassis through a lifting linkage mechanism, and the lifting linkage mechanism drives the seat to rise as the backrest assembly reclines. When the backrest assembly reclines, the upper end of the lumbar support moves backward and downward, and the lower end of the lumbar support moves upward. The seat is movably arranged on the chassis, and when switching from an upright state to a tilted state, the lifting movement of the seat can allow the lumbar support to rotate at a larger angle, thereby achieving more reasonable lumbar support.

[0038] Preferably, the lifting linkage mechanism includes a seesaw, the rear end of the seesaw is relatively fixedly connected to the backrest assembly, the front end of the seesaw is rotatably connected to the seat, and the middle of the seesaw is rotatably connected to the chassis. The backrest assembly and the seat are linked by the seesaw, and the lifting and lowering of the backrest assembly relative to the chassis can also be directly driven by the backrest reclining without additional manual operation. The backrest assembly, lumbar support and seat in the seat are all in a linkage relationship.

[0039] Preferably, the lifting linkage mechanism further includes a guide part, which is installed under the seat and is rotatably connected to the front end of the rocker; the chassis is open upward and backward and is hollow, the guide part is arranged in the chassis from top to bottom, a guide member and a guide groove are arranged between the guide part and the chassis, the guide member is arranged in the guide groove, and the guide part is configured so that when the backrest is reclined, the guide member moves in the guide groove and provides guidance for the movement direction of the seat. The guide member and the guide groove limit the movement trajectory of the seat, making the linkage of the backrest assembly, the lumbar support and the seat more reasonable.

[0040] Preferably, the lifting linkage mechanism is a lifting connecting rod assembly arranged in the chassis.

[0041] The design starting point, concept and beneficial effects of the utility model using the above technical solution are:

[0042] As more and more seats have similar functions, the design focus and mainstream have gradually shifted from manual adjustment to linkage. Compared with adjustments that require manual operation, the linkage of the mechanism is more convenient, tends to be automated, and appears to be more intelligent. For different functions, it is also important to reasonably allocate and use manual adjustment and linkage. For example, the position adjustment of parts such as armrests can be done manually, while the chair back tilt switching discussed in the present invention can replace the additional operating actions in manual adjustment because the user will drive the chair back to move when lying down. Therefore, the use of linkage is more reasonable and simpler.

[0043] Furthermore, the chair back assembly is rotatably arranged relative to the seat, and the chair back assembly has a basic reclining function. The lumbar support is rotatably connected to the seat and the chair back assembly. When a human body leans on it, the chair back assembly can drive the lumbar support to rotate relative to the seat, thereby realizing the switching of the mechanism between an upright state and a tilted state. Since the lumbar support is directly or indirectly rotatably connected to the seat, the lumbar support and the seat will not produce relative displacement movement in the front-to-back direction. A part of the lumbar support is always located above the seat. Therefore, in the front-to-back direction, the lower end of the lumbar support will not move backward beyond the rear end of the seat, so that there will be no gap between the seat and the lumbar support in the front-to-back direction, and the human body's waist and back can be fully and continuously supported, so that the waist can be reasonably and effectively supported without a feeling of empty waist.

[0044] In the upright state, the chair back assembly and the lumbar support can support the human body's waist and back, and fit the roughly S-shaped waist and back curve of the human body. In the tilted state, the angle between the lumbar support and the chair back assembly decreases, and the curved surface formed by the two changes, and can fit the roughly straight waist and back curve when the human body leans back. Therefore, when the human body sits or lies normally, the curved surfaces formed by the lumbar support and the chair back assembly conform to the ergonomics in their respective states, so as to provide a better comfortable sitting and lying feeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a three-dimensional structural schematic diagram of the seat when the waist-back linkage mechanism in the embodiment of the utility model is in an upright state;

[0046] Figure 2 It is a side view of the seat when the waist-back linkage mechanism in the embodiment of the utility model is in an upright state;

[0047] Figure 3 It is a cross-sectional view of the seat when the waist-back linkage mechanism in the embodiment of the utility model is in an upright state;

[0048] Figure 4 It is a three-dimensional structural schematic diagram of the waist support and the moving parts when the waist-back linkage mechanism is in an upright state in the embodiment of the utility model;

[0049] Figure 5This is a three-dimensional structural diagram of the seat in the embodiment of the utility model, in which the waist-back linkage mechanism is in a tilted state;

[0050] Figure 6 It is a side view of the seat in the embodiment of the utility model with the waist and back linkage mechanism in a tilted state;

[0051] Figure 7 It is a cross-sectional view of the seat in the embodiment of the utility model, in which the waist-back linkage mechanism is in a tilted state;

[0052] Figure 8 It is a three-dimensional structural schematic diagram of the waist support and moving parts when the waist-back linkage mechanism is in a tilted state in the embodiment of the utility model;

[0053] Fig. 9 This is a schematic diagram of the three-dimensional structure of the seesaw connected to the chassis and the guide part in the embodiment of the utility model;

[0054] Fig.10 It is a schematic diagram of the three-dimensional structure of the fitting surface formed when the waist-back linkage mechanism is in an inclined state in the embodiment of the utility model;

[0055] Fig.11 This is a schematic diagram of the use of the seat in the embodiment of the utility model, in which the waist and back linkage mechanism is in an upright state;

[0056] Fig.12 This is a schematic diagram of the use of the seat in the embodiment of the utility model, in which the waist and back linkage mechanism is in a tilted state;

[0057] Fig.13 This is a side view of the seat when the waist-back linkage mechanism is in an upright state when the moving part is an elastic body in the embodiment of the utility model

[0058] Fig.14 This is a side view of the seat when the moving part is an elastic body in the embodiment of the utility model and the waist and back linkage mechanism is in a tilted state

[0059] Fig.15 This is a side view of the seat when the waist-back linkage mechanism is in an upright state when the moving part is a sleeve assembly in the embodiment of the utility model

[0060] Fig.16 It is a side view of the seat when the moving part in the embodiment of the utility model is a sleeve assembly and the waist and back linkage mechanism is in a tilted state.

[0061] The figures are marked as follows: seat 1; backrest assembly 2; lumbar support 3; chassis 4; moving part 5; back support 6; extension seat 7; sliding rotating part 8; limiting column 9; slide groove 10; limiting groove 11; rocker 12; guide part 13; guide part 14; guide groove 15; rotating frame 16; fixing part 161; support arm 162; reference line 17. DETAILED DESCRIPTION

[0062] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0063] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0064] In the description of the present invention, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0065] The specific implementation of the utility model is as follows:

[0066] When a user sits on the chair normally, the curve of his / her waist and back is S-shaped. In order to adapt to and fit the S-shaped curve, the backrests of existing chairs will specially increase the convexity of the waist position; when the user lies on the chair, the curve of his / her waist and back is roughly straight. At this time, the convexity of the waist position of the backrest will not only compress the waist and back of the human body, making the user lie in an uncomfortable posture, but also, in existing conventional chairs, after the lumbar support 3 rotates with the backrest, the lumbar support 3 will be separated from the seat 1, and the gap between the two cannot be used to support the human waist. Therefore, the supporting effect on the human waist is poor, and the comfort is greatly reduced.

[0067] Since the buttocks are connected to the waist, when the human body lies down, there is an angle between the buttocks and the waist. If the chair back is completely located behind the seat 1 like a conventional chair, a gap will be created between the seat 1 and the chair back, and the waist above the buttocks will be higher than the chair back and the seat 1. The gap between the seat 1, the chair back and the waist makes the waist unsupported, resulting in poor comfort. If the waist is to be supported, the lumbar support 3 must be able to fill this gap; but if the existing technology is used, even if the gap between the lumbar support 3 and the seat 1 is removed, it is impossible to give a suitable angle to support the waist. The reason is that, regardless of the single-back structure or the double-back structure, when the chair back is reclined, the lumbar support 3 always moves with the chair back assembly 2. While rotating, the lumbar support 3 also has a downward and backward displacement movement, which reduces its height and naturally cannot support the human waist. Therefore, the chair back of the existing chair always has the problem of an empty waist.

[0068] like Figure 1 , 5As shown in Figures 11 and 12, the utility model provides a waist-back linkage mechanism, which is applied in a seat, which includes a seat 1, a backrest assembly 2, a lumbar support 3 and a chassis 4. The seat 1 is configured to support the buttocks of a human body, the backrest assembly 2 is configured to support the back of a human body, the backrest assembly 2 and the seat 1 are relatively rotatable, the lumbar support 3 is configured to support the waist of a human body, the lumbar support 3 is rotatably connected to the seat 1, and the lumbar support 3 is also rotatably connected to the backrest assembly 2 and the two are linked; the seat 1 is set on the chassis 4, the backrest assembly 2 is rotatably connected to the chassis 4 to achieve a relative rotation setting with the seat 1, when the backrest assembly 2 and the chassis 4 rotate, the backrest assembly 2 rotates relative to the seat 1, and the lumbar support 3 also rotates relative to the backrest assembly 2 and the seat 1.

[0069] The waist-back linkage mechanism includes the above-mentioned seat 1, seat back assembly 2 and lumbar support 3. The waist-back linkage mechanism has an upright state and a tilted state. In the upright state, the seat back assembly 2 and the lumbar support 3 are vertical and both face forward, so that the human body can sit normally; in the tilted state, the seat back assembly 2 leans back, and the lumbar support 3 tilts and faces upward, so that the human body can lie down; when switching from the upright state to the tilted state, the seat back assembly 2 rotates backward relative to the seat 1, and the lumbar support 3 moves as the seat back assembly 2 leans back, and the angle between the lumbar support 3 and the seat back assembly 2 is reduced to change the relative posture of the lumbar support 3 and the seat back assembly 2, thereby adapting to the different waist and back positions of the human body when sitting and lying down; in both states, the front end of the lumbar support 3 is always located above the seat 1.

[0070] As more and more seats have similar functions, the design focus and mainstream have gradually shifted from manual adjustment to linkage. Compared with adjustments that require manual operation, the linkage of the mechanism is more convenient, tends to be automated, and appears to be more intelligent. For different functions, it is also important to reasonably allocate and use manual adjustment and linkage. For example, the position adjustment of parts such as armrests can be done manually, while the chair back tilt switching discussed in the present invention can replace the additional operating actions in manual adjustment because the user will drive the chair back to move when lying down. Therefore, the use of linkage is more reasonable and simpler.

[0071] Furthermore, the chair back assembly 2 is rotatably arranged relative to the seat 1, and the chair back assembly 2 has a basic reclining function. The lumbar support 3 is rotatably connected to the seat 1 and the chair back assembly 2. When a human body leans on it, the chair back assembly 2 can drive the lumbar support 3 to rotate relative to the seat 1, thereby realizing the switching of the mechanism between an upright state and a tilted state. Since the lumbar support 3 is directly or indirectly rotatably connected to the seat 1, the lumbar support 3 and the seat 1 will not produce relative displacement movement in the front-to-back direction. A part of the lumbar support 3 is always located above the seat 1. Therefore, in the front-to-back direction, the lower end of the lumbar support 3 will not exceed the rear end of the seat 1 backwards, so that there will be no gap between the seat 1 and the lumbar support 3 in the front-to-back direction, and the human waist and back can be fully and continuously supported, so that the waist can be reasonably and effectively supported without a feeling of empty waist.

[0072] Furthermore, the chair back assembly is rotatably arranged relative to the seat, and the chair back assembly has a basic reclining function. The lumbar support is rotatably connected to the seat and the chair back assembly. When a human body leans on it, the chair back assembly can drive the lumbar support to rotate relative to the seat, thereby realizing the switching of the mechanism between an upright state and a tilted state. Since the lumbar support is directly or indirectly rotatably connected to the seat, the lumbar support and the seat will not produce relative displacement movement in the front-to-back direction. A part of the lumbar support is always located above the seat. Therefore, in the front-to-back direction, the lower end of the lumbar support will not move backward beyond the rear end of the seat, so that there will be no gap between the seat and the lumbar support in the front-to-back direction, and the human body's waist and back can be fully and continuously supported, so that the waist can be reasonably and effectively supported without a feeling of empty waist.

[0073] In the upright state, the chair back assembly 2 and the lumbar support 3 can support the human body's waist and back, and fit the roughly S-shaped human waist and back curve. In the tilted state, the angle between the lumbar support 3 and the chair back assembly 2 decreases, and the curved surface formed by the two changes, and can fit the roughly straight waist and back curve when the human body leans back. Therefore, when the human body sits or lies normally, the curved surface formed by the lumbar support 3 and the chair back assembly 2 conforms to the ergonomics in their respective states, so as to provide a better comfortable sitting and lying feeling.

[0074] In order to realize the linkage between the backrest assembly 2 and the lumbar support 3, it is also necessary to set a moving part 5 between the backrest assembly 2 and the lumbar support 3 and / or let the seat 1 be movably set on the chassis 4; the lumbar support 3 is rotatably connected with the backrest assembly 2 and the seat 1, the backrest assembly 2 is rotatably connected with the chassis 4, and the seat 1 is set on the chassis 4. If the backrest assembly 2 and the chassis 4 are relatively fixed, and the lumbar support 3 is only rotatably connected with the backrest assembly 2 and the seat 1, then when the backrest assembly 2 leans back to drive the lumbar support 3 to rotate, the movement will be restricted. In order to make the movement run smoothly, additional structural settings are required; in this embodiment, a moving part 5 is provided between the backrest assembly 2 and the lumbar support 3, and the seat 1 is set on the chassis 4 through a lifting linkage mechanism.

[0075] Specifically, a moving part 5 is provided between the backrest assembly 2 and the lumbar support 3, and the backrest assembly 2 and the lumbar support 3 are arranged to move relative to each other through the moving part 5; when the backrest assembly 2 rotates backward relative to the seat 1, the lumbar support 3 and the backrest assembly 2 rotate relative to each other and the lumbar support 3 and the backrest assembly 2 move away from each other; a moving part 5 is provided between the backrest assembly 2 and the lumbar support 3 to enable the two to move relative to each other, so that the movement between the lumbar support 3, the backrest assembly 2 and the seat 1 can be carried out smoothly; in addition to providing the moving part 5 between the backrest assembly 2 and the lumbar support 3, the moving part 5 can also be provided between the lumbar support 3 and the seat 1, and the same function and effect can also be achieved by rotatably connecting the backrest assembly 2 and the chassis 4, and the chassis 4 and the seat 1 move relative to each other.

[0076] like Figure 13-16As shown, there are multiple options for the moving part 5. The moving part 5 can be a connecting rod assembly, an elastomer, or a telescopic sleeve assembly. When the moving part 5 is a connecting rod assembly, the lumbar support 3 and the seat back assembly 2 can be rotated relative to each other and moved relative to each other through the connecting rod in the connecting rod assembly; when the moving part 5 is an elastomer, the upper end of the lumbar support 3 is hinged to the elastomer, and the elastomer is deformed when the lumbar support 3 and the seat back assembly 2 move relative to each other; when the moving part 5 is a telescopic sleeve assembly, one end of the sleeve assembly is relatively fixedly connected to the seat back assembly 2, and the other end of the telescopic sleeve is rotatably connected to the upper end of the lumbar support 3; all three can allow the linkage between the seat back assembly 2 and the lumbar support 3 to proceed smoothly.

[0077] like Figure 4 , 8 As shown, in this embodiment, the chair back assembly 2 includes a backrest for leaning against the back of a human body and a back bracket 6 connected to the lower part of the backrest, the back bracket 6 is arranged to rotate relative to the chassis 4, the lower end of the backrest is relatively fixedly connected to the upper end of the back bracket 6, and the backrest and the back bracket 6 are integrally formed; the moving part 5 includes an extension seat 7 and a sliding rotating part 8; the extension seat 7 is fixedly installed on the back bracket 6 below the backrest facing forward, one end of the sliding rotating part 8 is rotatably connected to the upper end of the lumbar support 3, and the sliding rotating part 8 is slidably matched with the extension seat 7; when the chair back assembly 2 rotates backward relative to the seat 1, the lumbar support 3 rotates with the sliding rotating part 8 and generates relative rotation with the chair back assembly 2, and at the same time, the sliding rotating seat and the extension seat 7 slide relative to each other, and the moving part 5 extends; a limiting column 9 is provided at the end of the sliding rotating part 8 facing the extension seat 7, and a limiting column 9 is provided on both sides of the sliding rotating part 8, and a slide groove 10 is opened along the length direction of the extension seat 7, and the sliding rotating part 8 is arranged in the slide groove 10, A limiting groove 11 is provided on the extension seat 7 beside the slide groove 10, and a limiting column 9 is arranged in the limiting groove 11. The trajectory of the limiting groove 11 is arranged along the extension direction of the extension seat 7. In the upright state, the extension seat 7 bends downward from front to back; when using the moving part 5, the moving part 5 does not need to be operated. It realizes adaptive changes with the movement of the chair back assembly 2 and the lumbar support 3, so that the movement of the mechanism is smooth and smooth; the moving part 5 is arranged to adapt to the movement of the lumbar support 3, the chair back assembly 2 and the seat 1. The sliding rotating part 8 in the moving part 5 and the extension seat 7 move adaptively with the movement of the three. The limiting column 9 moves in the slide groove 10 to limit the movement trajectory of the sliding rotating part 8. At the same time, the moving part 5 and the lumbar support 3 limit the movement trajectories of both parties to achieve the preset movement mode of the mechanism; finally, the shape of the extension seat 7, that is, the shape of the limiting groove 11, both adapts to the movement of the lumbar support 3 and limits the movement trajectory of the sliding rotating part 8.

[0078] like Figure 3 , 7As shown in Figures 9 and 10, the seat 1 is arranged on the chassis 4 through a lifting linkage mechanism. The lifting linkage mechanism drives the seat 1 to rise as the backrest assembly 2 reclines. When the backrest assembly 2 reclines, the upper end of the lumbar support 3 moves backward and downward, and the lower end of the lumbar support 3 moves upward. The seat 1 is movably arranged on the chassis 4. When switching from an upright state to a tilted state, the lifting movement of the seat 1 can make the lumbar support 3 rotate at a larger angle, thereby achieving more reasonable lumbar support. Specifically, the lifting linkage mechanism includes a seesaw 12, the rear end of the seesaw 12 is relatively fixedly connected to the backrest assembly 2, the front end of the seesaw 12 is rotatably connected to the seat 1, and the middle part of the seesaw 12 is rotatably connected to the chassis 4. The lifting linkage mechanism also includes a guide portion 13, which is installed below the seat 1 and is rotatably connected to the front end of the seesaw 12. The chassis 4 is open upward and backward and is hollow. The guide part 13 is arranged in the chassis 4 from top to bottom. A guide member 14 and a guide groove 15 are arranged between the guide part 13 and the chassis 4. The guide member 14 is arranged in the guide groove 15. The guide groove 15 is inclined upward from front to back. The guide part 13 is configured so that when the backrest is reclined, the guide member 14 moves in the guide groove 15 and provides guidance for the movement direction of the seat 1; the linkage between the backrest assembly 2 and the seat 1 is realized by the seesaw 12. The rise and fall of the backrest assembly 2 relative to the chassis 4 can also be directly driven by the backrest reclining without additional manual operation. The backrest assembly 2, the lumbar support 3 and the seat 1 in the seat are all in a linkage relationship; the guide member 14 and the guide groove 15 limit the movement trajectory of the seat 1, making the linkage between the backrest assembly 2, the lumbar support 3 and the seat 1 more reasonable. In addition to using the solution of this embodiment, the lifting linkage mechanism can also be replaced by a lifting connecting rod assembly to achieve the same effect. The lifting linkage mechanism of this embodiment has a simpler structure.

[0079] The seat 1 is arranged on the chassis 4, and the backrest assembly 2 is rotatably connected to the chassis 4. By adding the chassis 4 to the seat 1, the backrest assembly 2, and the lumbar support 3 of the above-mentioned mechanism, the diversity of movement can be achieved. That is, when the chassis 4 is fixed as a basis, the backrest assembly 2 is rotatably connected to the chassis 4 to achieve relative rotation with the seat 1. A movable connection can also be selectively set between the seat 1 and the chassis 4, so that the movement of the backrest assembly 2 is opposite to that of the seat 1, so that the lumbar support 3 can have a larger rotation angle.

[0080] Furthermore, a rotating frame 16 is provided on the seat 1, and the rotating frame 16 is relatively fixed to the seat 1, the rotating frame 16 is located at the rear of the seat 1, and the rotating frame 16 extends upward and is rotatably connected to the lumbar support 3; the lumbar support 3 is connected to the rotating frame 16 instead of being directly connected to the seat 1. On the one hand, the height of the lumbar support 3 is raised, so that the lumbar support 3 has a height similar to that of the existing seat in an upright state, thereby achieving the desired function. At the same time, the lumbar support 3 will not interfere with the seat 1 when rotating, and the seat 1 can be effectively avoided; on the other hand, the lumbar support 3 is rotatably connected to the rotating frame 16, which is obviously different from the rotation connection point of the seat back assembly 2, and in this case, the lumbar support 3 can be rotated at a larger angle, so that the angle between the lumbar support 3 and the seat back assembly 2 is reduced, thereby achieving the desired effect.

[0081] Specifically, the lumbar support 3 is a frame structure, and the rotating frame 16 includes a fixing portion 161 located at its lower end, and the fixing portion 161 is fixedly connected to the rear end of the seat 1 by screws. Two divergent support arms 162 extend from the upper end of the rotating frame 16, and the two support arms 162 extend to the left and right sides respectively and tilt forward and upward, and finally the ends of the support arms 162 are rotatably connected to the middle and lower parts of the lumbar support 3 through a rotating shaft; in this embodiment, the rotating frame 16 and the lumbar support 3 are rotatably connected to the middle or lower parts of the lumbar support 3, and the rotating frame 16 and the lumbar support 3 are rotatably connected to the lower end of the lumbar support 3, which can also achieve better lumbar support than the prior art, but the selection effect of this embodiment is better, the lower end of the lumbar support 3 is vacant and located below the rotation connection point between the lumbar support 3 and the rotating frame 16, and the lower end of the lumbar support 3 can extend forward under the human waist in an inclined state for support, so as to provide more comfortable lumbar support.

[0082] like Figure 2 , 6As shown in 10-12, the chair back assembly 2 and the lumbar support 3 form a supporting surface that fits the human waist and back, and the chair seat 1 forms a seat surface that fits the human buttocks. The supporting surface and the seat surface form a continuous fitting surface, and the fitting surface fits both the human buttocks and the waist and back. Since the existing chair backs are often curved backwards to improve comfort, so that the human body sinks into it and feels wrapped, in order to more accurately describe the fit between the chair back and the human waist and back, the supporting surface has a reference line 17. The reference line 17 is located in the middle of the supporting surface in the left-right direction, and the reference line 17 is a line connecting the upper end of the chair back assembly 2 to the lower end of the lumbar support 3 on the supporting surface. In the upright state, the reference line 17 is an S-shaped curve with a convex lower portion. In the tilted state, the reference line 17 is approximately a straight line with a certain backward curvature. Specifically, the reference line 17 reflects the overall state of the supporting surface. In the upright state, the reference line 17 is an S-shaped curve with a convex lower portion, that is, in the upright state, the lumbar support 3 protrudes forward relative to the chair back assembly 2, and is used to press forward on the human waist to fit the S-shaped waist and back curve of the human body when sitting normally; in the tilted state, the reference line 17 is approximately a straight line, that is, in the tilted state, the angle between the lumbar support 3 and the chair back assembly 2 is reduced, and the shape of the supporting surface is changed to fit the linear waist and back curve of the human body when lying down.

[0083] In addition, when switching from an upright state to a tilted state, the supporting surface is close to the seat surface; when switching from the upright state to the tilted state, the supporting surface is close to the seat surface, which means that when switching from the upright state to the tilted state, the lumbar support 3 rotates, and its lower end is close to the seat 1, unlike a conventional seat where the lumbar support 3 is far away from the seat 1, so that the lumbar support 3 and the seat 1 will not separate to form a gap, thereby preventing the waist from being empty when the human body lies down.

[0084] In this embodiment, in the upright state and the inclined state, the fitting surface is continuous rather than disconnected, so that the buttocks, waist and back of the human body can all be pressed against the fitting surface, and the buttocks and waist and back of the human body can all be effectively and reasonably supported without the condition of an empty waist.

[0085] Although the human waist and back are roughly in a straight line, it is not advisable for the lumbar support 3 and the supporting surface of the chair back assembly 2 to be completely straight. In the double-back structure, the reference line 17 at the chair back assembly 2 is generally a straight line, and the reference line 17 at the lumbar support 3 is also a straight line. An angle will be generated between the lumbar support 3 and the seat surface, without a smooth transition, and there will be a gap below the waist. If the lumbar support 3 is designed with a rounded concave shape for lying, the effect of the lumbar support 3 convexly fitting and supporting when sitting normally will be lost, which is not worth the loss. Therefore, in this embodiment, a conventional convex lumbar support 3 is used to ensure comfortable waist support in normal sitting posture. In an upright state, the human waist is supported by the middle and upper part of the lumbar support 3. The support is close fitting, and when the upright state is switched to the inclined state, the lumbar support 3 and the chair back assembly 2 rotate relative to each other, thereby changing the shape of the supporting surface, and the human waist is supported by the middle and lower parts of the lumbar support 3, alleviating the convexity of the lumbar support 3, so that the lumbar support 3 and the chair back assembly 2 are roughly straight to fit the human waist and back; that is, while the supporting surface of the lumbar support 3 transitions more smoothly to the supporting surface of the chair back assembly 2, the lumbar support 3 still has a certain convexity to fill the gap and maintain sufficient lumbar support. The shape of the supporting surface is straighter, and the reference line 17 has a slight backward bend, so that the human waist and back remain roughly straight and lean on the chair back assembly 2 and the lumbar support 3 reasonably and comfortably.

[0086] Regarding the rotation angle, specifically, when switching from the upright state to the inclined state, the rotation angle of the lumbar support 3 is greater than the rotation angle of the backrest assembly 2; in this way, the angle between the lumbar support 3 and the backrest assembly 2 can be reduced; the reason why the rotation angle of the lumbar support 3 is greater than the rotation angle of the backrest assembly 2 is because the rotation connection points of the lumbar support 3 and the backrest assembly 2 are different, the backrest assembly 2 is rotationally connected to the chassis 4 and the lumbar support 3 is rotationally connected to the rotating frame 16 on the seat 1.

[0087] Furthermore, if Fig.11 , 12 As shown, in the tilted state, the tilt angle of the lumbar support 3 relative to the ground is 13-20°. In the present embodiment, in the tilted state, the tilt angle of the lumbar support 3 relative to the ground is 14°; in the upright state, the angle between the lumbar support 3 and the seat 1 is 115-120°. In the tilted state, the angle between the lumbar support 3 and the seat is 158-165°. In the present embodiment, the angle between the lumbar support 3 and the seat in the upright state is 116°. In the tilted state, the angle between the lumbar support 3 and the seat is 160°. The rotation angle of the lumbar support 3 is 43-50°. In the present embodiment, the rotation angle of the lumbar support 3 is 44°.

[0088] The inclination angle of the lumbar support 3 of the mechanism relative to the ground in the inclined state is significantly smaller than the inclination angle of the lumbar support 3 in the existing seat, so that the inclination angle of the lumbar support 3 of the mechanism relative to the vertical plane is larger, and its orientation is closer to upward to support the human waist; from the upright state to the inclined state, the angle between the lumbar support 3 and the seat 1 becomes larger. In the upright state, the angle between the lumbar support 3 and the seat 1 is similar to that of a conventional seat, but in the inclined state, the angle between the lumbar support 3 and the seat 1 is significantly larger, the lumbar support 3 is more inclined, and the orientation of the lumbar support 3 tends to be upward, so that the support for the human waist is more reasonable, and the user can get a more comfortable experience; the rotation angle of the lumbar support 3 of the mechanism is larger than the rotation angle of the lumbar support 3 of the existing seat. The purpose is to make the lumbar support 3 more inclined and more reasonably oriented, so as to support the human waist in a better posture and improve comfort.

[0089] Furthermore, when switching from the upright state to the inclined state, the backrest assembly 2 reclines relative to the seat 1, and the lumbar support 3 rotates with the backrest assembly 2 relative to the seat 1. At the same time, the lumbar support 3 rotates relative to the backrest assembly 2 so that the lumbar support 3 has a tendency to push forward relative to the backrest assembly 2. Since the lumbar support 3 is rotatably connected to the seat 1, the lumbar support 3 and the backrest assembly 2 are also relatively rotatably arranged. When the backrest assembly 2 reclines, the lumbar support 3 rotates relative to both the backrest assembly 2 and the seat 1. Unlike the prior art, the lumbar support 3 is not connected to the backrest assembly 2 to form the same rotation with the backrest assembly 2 as the seat 1, but rotates independently with the backrest assembly 2 relative to the seat 1. Therefore, while the lumbar support 3 and the seat 1 rotate relative to each other, the rotation angles and positions of the two relative to the seat 1 are different. Therefore, for the reclining backrest assembly 2, the lumbar support 3 rotatably connected to the seat 1 has a tendency to push forward relative to each other. This tendency to push forward relative to each other improves the support of the lumbar support 3 to the human waist and prevents the appearance of an empty waist.

Claims

1. A waist-back linkage mechanism, characterized in that: include: A seat configured to support a buttocks of a human body; The backrest assembly is configured to support the back of a human body, and the backrest assembly and the seat are relatively rotatable; The lumbar support is rotatably connected to the seat, the lumbar support is linked with the chair back assembly and the lumbar support and the chair back assembly are relatively rotatably arranged; the lumbar support is configured to support the waist of a human body; The lumbar-back linkage mechanism has an upright state and a tilted state. In the upright state, the chair back assembly and the lumbar support are vertical and both face forward, so that the human body can sit normally; in the tilted state, the chair back assembly leans back, and the lumbar support tilts and faces upward, so that the human body can lie down; when switching from the upright state to the tilted state, the chair back assembly rotates backward relative to the seat, and the lumbar support moves as the chair back assembly leans back, and the angle between the lumbar support and the chair back assembly decreases to change the relative posture of the lumbar support and the chair back assembly, thereby adapting to the waist and back support of the human body when sitting or lying down.

2. The waist-back linkage mechanism according to claim 1, characterized in that: The chair back assembly and the lumbar support form a supporting surface that fits the waist and back of the human body. The supporting surface has a reference line. The reference line is located in the middle of the supporting surface in the left-right direction, and the reference line is a line connecting the upper end of the chair back assembly to the lower end of the lumbar support on the supporting surface. In the upright state, the reference line is an S-shaped curve with a convex lower part, and in the inclined state, the reference line is roughly a straight line.

3. The waist-back linkage mechanism according to claim 2, characterized in that: The chair seat is formed with a seat surface that fits the buttocks of a human body, and when the chair seat is switched from an upright state to a tilted state, the supporting surface and the seat surface are close to each other.

4. The waist-back linkage mechanism according to claim 3, characterized in that: In the upright state and the inclined state, the front end of the lumbar support is always located above the seat; the supporting surface and the seat surface form a continuous fitting surface, and the fitting surface fits with the buttocks, waist and back of the human body.

5. The waist-back linkage mechanism according to claim 1, characterized in that: When switching from an upright state to a tilted state, the rotation angle of the lumbar support is greater than the rotation angle of the seat back assembly.

6. The waist-back linkage mechanism according to claim 1, characterized in that: In the tilted state, the lumbar support has an inclination angle of 13-20° relative to the ground.

7. The waist-back linkage mechanism according to claim 1, characterized in that: In the upright state, the angle between the lumbar support and the seat is 115-120°, and in the tilted state, the angle between the lumbar support and the seat is 158-165°.

8. The waist-back linkage mechanism according to claim 1, characterized in that: The lumbar support has a rotation angle of 43-50°.

9. A waist-back linkage mechanism, characterized in that: The utility model comprises a seat, a chair back assembly and a lumbar support, wherein the lumbar support and the seat are arranged to rotate relative to each other, the lumbar support and the seat are rotatably connected, and the lumbar support and the chair back assembly are linked and arranged to rotate relative to each other; the lumbar support linkage mechanism has an upright state for supporting a human body to sit normally and an inclined state for supporting a human body to lie down; when switching from the upright state to the inclined state, the chair back assembly leans back relative to the seat, and the lumbar support rotates with the chair back assembly relative to the seat, and at the same time, the lumbar support rotates relative to the chair back assembly so that the lumbar support is pushed forward relative to the chair back assembly.

10. The waist-back linkage mechanism according to claim 9, characterized in that: A moving part is arranged between the backrest assembly and the lumbar support, and the backrest assembly and the lumbar support are relatively movable through the moving part; when the backrest assembly rotates backward relative to the seat, the lumbar support and the backrest assembly rotate relatively and move away from each other.

11. The waist-back linkage mechanism according to claim 10, characterized in that: The moving part includes an extension seat and a sliding rotating part; the extension seat is fixedly connected to the chair back assembly, the sliding rotating part and the extension seat are slidably matched, and the lumbar support is rotatably connected to the sliding rotating part; when the chair back assembly rotates backward relative to the seat, the lumbar support and the sliding rotating part rotate and rotate relative to the chair back assembly, and at the same time the sliding rotating part and the extension seat slide relative to each other, and the moving part extends.

12. The waist-back linkage mechanism according to claim 11, characterized in that: One end of the sliding rotating member is rotatably connected to the upper end of the lumbar support, and the other end of the sliding rotating member is provided with a limiting column; the extension seat is provided with a sliding groove along the length direction, the sliding rotating member is arranged in the sliding groove, and the extension seat beside the sliding groove is provided with a limiting groove, and the limiting column is arranged in the limiting groove.

13. The waist-back linkage mechanism according to claim 11, characterized in that: In an upright state, the extension seat bends downward from front to back.

14. The waist-back linkage mechanism according to claim 10, characterized in that: The moving part is a connecting rod assembly, and the connecting rod assembly is configured to enable the lumbar support and the chair back assembly to rotate relative to each other and move relative to each other at the same time.

15. The waist-back linkage mechanism according to claim 10, characterized in that: The moving part is a telescopic sleeve assembly, one end of which is relatively fixedly connected to the chair back, and the other end of which is rotatably connected to the upper end of the waist support.

16. The waist-back linkage mechanism according to claim 10, characterized in that: The moving part is an elastic body, the upper end of the lumbar support is hinged to the elastic body, and the elastic body is configured to deform when the lumbar support and the chair back assembly move relative to each other.

17. The waist-back linkage mechanism according to claim 9, characterized in that: A rotating frame is arranged on the chair seat, the rotating frame is relatively fixed with the chair seat, the rotating frame is located at the rear of the chair seat, and the rotating frame extends upward and is rotatably connected with the waist support.

18. The waist-back linkage mechanism according to claim 17, characterized in that: The rotating frame is rotatably connected with the waist support at the middle part of the waist support.

19. The waist-back linkage mechanism according to claim 9, characterized in that: The chair back assembly includes a backrest for resting against the back of a human body and a back bracket connected below the backrest. The back bracket is rotatably arranged relative to the seat. The lower end of the chair back assembly is relatively fixedly connected to the upper end of the back bracket, and the upper end of the lumbar support is rotatably connected to the backrest or the back bracket.

20. A seat, characterized in that: It includes a chassis and a lumbar-back linkage mechanism as described in any one of claims 1-19, the seat is arranged on the chassis, the backrest assembly is rotatably connected to the chassis, when the backrest assembly and the chassis rotate, the backrest assembly rotates relative to the seat, and the lumbar support also rotates relative to the backrest assembly and the seat.

21. The sitting device according to claim 20, characterized in that: The seat is arranged on the chassis through a lifting linkage mechanism, and the lifting linkage mechanism drives the seat to rise as the seat back assembly reclines. When the seat back assembly reclines, the upper end of the lumbar support moves backward and downward, and the lower end of the lumbar support moves upward.

22. The sitting device according to claim 21, characterized in that: The lifting linkage mechanism comprises a seesaw, the rear end of the seesaw is relatively fixedly connected to the chair back assembly, the front end of the seesaw is rotatably connected to the seat, and the middle part of the seesaw is rotatably connected to the chassis.

23. The sitting device according to claim 22, characterized in that: The lifting linkage mechanism also includes a guide part, which is installed under the seat and is rotatably connected to the front end of the rocker; the chassis is open upward and backward and is hollow, the guide part is arranged in the chassis from top to bottom, a guide member and a guide groove are provided between the guide part and the chassis, the guide member is arranged in the guide groove, and the guide part is configured so that when the backrest is reclined, the guide member moves in the guide groove and provides guidance for the movement direction of the seat.

24. The sitting device according to claim 21, characterized in that: The lifting linkage mechanism is a lifting link assembly arranged in the chassis.

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