Seat and backrest assembly

Abstract

The invention relates to a seat and a backrest assembly, and relates to the technical field of seats. A seat includes a backrest assembly, a seat portion, a chassis, and support legs. The backrest assembly comprises a chair back and a chair back support, the chair back support is rotatably connected with the chassis, and one end of the first connecting rod is hinged to the chair back support; one end of the mounting support is hinged to the other end of the first connecting rod, and the other end of the mounting support is hinged to the chair back; one end of the second connecting rod is hinged to the chair back bracket, and the other end of the second connecting rod is hinged to the mounting support; one end of the driving mechanism is hinged to the mounting supporting rod, the other end of the driving mechanism is provided with a telescopic rod, and the tail end of the telescopic rod is hinged to the lower area of the chair back; one end of the seat connecting piece is hinged to the first connecting rod, and the other end of the seat connecting piece is hinged to the seat; and the driving mechanism drives the telescopic rod to stretch out to drive the lower area of the chair back to generate forward ejection motion. The waist supporting device has the effect that stable and continuous waist supporting can be provided for a user.

Description

Technical Field

[0001] This application relates to the technical field of seating, and in particular to a seating and backrest assembly. Background Technology

[0002] In daily life and work, chairs are an important tool for maintaining posture, and their comfort directly affects the user's health and work efficiency. Currently, common chair backs are usually connected to the seat via a fixed hinge axis. This structure allows the backrest to tilt and rotate as a whole, but its rotation trajectory is limited to a single, fixed center of rotation.

[0003] From an ergonomic perspective, when the human body is seated, the lumbar spine naturally forms a forward physiological curvature. Therefore, ideal chair support should provide stable, conforming forward support in the area corresponding to the lower back, i.e., the lower part of the backrest, to maintain the normal physiological posture of the lumbar spine and relieve muscle and ligament load.

[0004] However, while existing backrest structures that rotate as a whole around a fixed hinge axis provide basic support, they have inherent limitations in lumbar support. Because the rotational movement of the entire backrest is fixed and uniform, the displacement trajectory and angular changes of the lower backrest area (corresponding to the lumbar region) during rotation do not match the forward support pattern required for the lumbar region when seated. During rotation, the lower backrest area struggles to adaptively conform to and support the user's lumbar curve, making it difficult to achieve effective dynamic fit and support. Prolonged use can lead to fatigue and discomfort in the user's lumbar region due to the lack of precise support. Summary of the Invention

[0005] To address the problem that existing chairs fail to provide effective lumbar support for users, this application provides a chair and backrest assembly.

[0006] The backrest assembly provided in this application adopts the following technical solution: A backrest assembly includes a chair back and a chair back support, the chair back support being rotatably connected to the chassis of a seat, and further includes: A first link, one end of which is hinged to the chair back support; Mounting support, one end of which is hinged to the other end of the first connecting rod, and the other end of which is hinged to the back of the chair back; The second link is located above the first link, with one end of the second link hinged to the chair back bracket and the other end of the second link hinged to the mounting bracket; A drive mechanism, one end of which is hinged to the mounting support rod, and the other end of which has a telescopic rod, the end of which is hinged to the lower region of the back of the chair. A seat connector, one end of which is hinged to the first connecting rod, and the other end of which is hinged to the seat of the chair; The drive mechanism is configured to extend the telescopic rod, thereby causing the lower region of the chair back to push forward relative to the chair back support.

[0007] By adopting the above technical solution, the chair back, chair back support, first link, second link, and seat connector form a multi-link system. When the drive mechanism is not activated, the mounting bracket is relatively fixed to the back of the chair back, and the first link is indirectly hinged to the back of the chair back. When the user leans back, the pressure on the chair back is transmitted to the chair back support, causing the chair back support to rotate backward. Under the combined action of the multi-link system, the entire chair back rotates backward while the lower part of the chair back moves forward. Furthermore, when the drive mechanism is activated, the upper end of the mounting bracket is relatively fixed, and the lower end of the mounting bracket, under the extension of the telescopic rod, pushes the lower part of the chair back forward. Compared to the slight forward push effect achievable by multi-link systems, the forward movement of the lower part of the chair back driven by the drive mechanism is unaffected by the seat's position. Whether the user is sitting upright or reclining, the chair back can provide lumbar support. Furthermore, the drive mechanism can control the amplitude and force of the chair back's forward thrust. Therefore, this application can provide stable and continuous effective support for the user's lumbar region.

[0008] Preferably, the mounting bracket includes a connecting part and a mounting part. One end of the connecting part is hinged to the back of the chair back, and the other end of the connecting part is provided with a hinge part. The end of the drive mechanism away from the telescopic rod is hinged to the hinge part, and the end of the mounting part away from the connecting part is hinged to the first connecting rod.

[0009] Preferably, the mounting part includes two mounting rods, which are respectively located on both sides of the connecting part. The hinge part is located between the two mounting rods, and the driving mechanism is located between the two mounting rods. The first connecting rod includes two first rods, and the ends of the two mounting rods away from the connecting part are respectively hinged to the two first rods.

[0010] Preferably, the seat connector includes two second support rods, one end of each second support rod is hinged to one of the first support rods, and the other end of each second support rod is hinged to the seat of the seat.

[0011] Preferably, when the drive mechanism is not activated, the triangle formed by the hinge point between the connecting part and the backrest, the hinge point between the hinge part and the drive mechanism, and the hinge point between the telescopic rod and the backrest is an obtuse triangle, and the hinge point between the hinge part and the drive mechanism is the obtuse vertex of the obtuse triangle.

[0012] Preferably, the drive mechanism is an electric push rod with a self-locking function.

[0013] A chair includes a backrest assembly as described above, and also includes a seat, a chassis, and support legs. The chassis is fixedly located below the seat, and the support legs are fixedly connected below the chassis. The chassis and the backrest support are rotatably connected by a hinge.

[0014] Preferably, the chassis includes an upper fixed seat, a lower fixed seat, and a third connecting rod. The upper fixed seat is fixedly connected to the lower part of the seat, the lower fixed seat is fixedly connected to the support leg, one end of the hinged seat is hinged to one end of the upper fixed seat and one end of the lower fixed seat, and the two ends of the third connecting rod are respectively hinged to the other ends of the upper fixed seat and the lower fixed seat.

[0015] Preferably, the lower fixed seat is provided with an elastic reset member and a force adjustment mechanism. Adjustment slots are provided on both sides of the hinge seat, and an adjustment shaft passes through the two adjustment slots. One end of the elastic reset member is connected to the adjustment shaft, and the other end of the elastic reset member is connected to the lower fixed seat. The force adjustment mechanism is configured to drive the adjustment shaft to move along the length direction of the adjustment slot and lock it in different positions.

[0016] Preferably, the force adjustment mechanism includes a gear assembly, a lifting component, and an adjusting linkage. The upper end of the adjusting linkage is connected to the adjusting shaft, the lower end of the adjusting linkage is connected to one end of the lifting component, and the other end of the lifting component is rotatably connected to the lower fixed seat. The gear assembly is connected to an adjusting handle. By rotating the adjusting handle, the gear assembly drives the lifting component to move up and down, thereby driving the adjusting linkage to drive the adjusting shaft to slide within the adjusting groove.

[0017] In summary, this application includes at least one of the following beneficial technical effects: It achieves a stable, continuous, reliable and efficient lumbar support effect, and the lumbar support function is actively controllable. Through an independent drive mechanism, it acts directly on the backrest, allowing the lower part of the backrest to recline independently of the whole body. It can also precisely control the amplitude and force of its forward thrust, which users can adjust in real time according to their own needs. This system improves overall performance, safety, and reliability by integrating the drive mechanism into a multi-link system, resulting in a better and more efficient transmission path for the driving force. The use of a self-locking drive mechanism ensures that the lumbar support position is securely locked after power failure or when the drive stops, achieving sustained support under low-energy conditions and enhancing the product's safety level and lifespan. It improves ease of operation. Traditional manual adjustment is laborious and has limited adjustment ranges. It can be controlled with one button by controlling the drive mechanism, and the adjustment process is smooth and effortless. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the seat in the embodiment of this application.

[0019] Figure 2 This is a three-dimensional structural diagram of the seat in the reclining state and the drive mechanism activated in the embodiment of this application.

[0020] Figure 3 This is a three-dimensional structural diagram of the seat in the reclining state and the drive mechanism not being activated in the embodiment of this application.

[0021] Figure 4 This is a partial structural diagram of the seat in an embodiment of this application.

[0022] Figure 5 This is an exploded view of the chassis in an embodiment of this application.

[0023] Figure 6 This is a schematic diagram of the internal structure of the chassis in an embodiment of this application.

[0024] Figure 7 This is a partial exploded view of the chassis structure in an embodiment of this application.

[0025] Figure 8 This is an exploded view of another partial structure of the chassis in an embodiment of this application.

[0026] Figure 9 This is a cross-sectional view of the chassis in an embodiment of this application.

[0027] Explanation of reference numerals in the attached drawings: 1. Seat; 2. Chassis; 3. Support leg; 11. Seat frame; 12. Armrest; 4. Backrest; 5. Backrest support; 6. Linkage assembly; 7. Drive mechanism; 8. Mounting bracket; 61. First link; 62. Second link; 63. Seat connector; 611. First support rod; 71. Telescopic rod; 81. Connecting part; 82. Mounting part; 83. Hinge part; 821. Mounting support rod; 631. Second support rod; 632. Connecting support rod; 9. 21. Hinge seat; 22. Upper fixed seat; 23. Lower fixed seat; 24. Third connecting rod; 91. First side plate; 92. Connecting plate; 211. Second side plate; 212. Fixed plate; 24. Elastic reset component; 25. Fixed shaft; 26. Adjusting shaft; 911. Adjusting groove; 27. Force adjustment mechanism; 271. Gear assembly; 272. Lifting component; 273. Adjusting connecting rod; 274. First gear; 275. Second gear; 276. Adjusting handle; 277. Adjusting block. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1-9 This application will be described in further detail.

[0029] This application discloses a type of seat. (Refer to...) Figure 1 and Figure 2 The seat includes a backrest assembly, a seat 1, a base 2, and support legs 3. The seat 1 is for the user to sit on and includes a seat frame 11 and a pair of armrests 12. A seat cushion is installed on the seat frame 11 for comfortable sitting. The armrests 12 are fixedly connected to both sides of the seat frame 11. The base 2 is fixedly connected to the bottom of the seat frame 11, and the support legs 3 are fixed to the bottom of the base 2. The backrest assembly includes a backrest 4, a backrest support 5, a linkage assembly 6, a drive mechanism 7, and a mounting bracket 8. The backrest support 5 is rotatably connected to the base 2. The backrest support 5 is movably connected to the backrest 4 and the seat 1 respectively through the linkage assembly 6. The mounting bracket 8 is movably connected to the linkage assembly 6. The main body of the drive mechanism 7 is mounted on the mounting bracket 8. The drive mechanism 7 has a telescopic end, which is hinged to the backrest 4. When the user leans back, the backrest 4 is pressed and causes the backrest support 5 to rotate backward relative to the chassis 2. Under the action of the linkage assembly 6, the backrest 4 is driven to rotate backward by the backrest support 5. Then, by extending the telescopic end of the drive mechanism 7, the lower part of the backrest 4 is pushed forward, thereby providing support for the user's waist.

[0030] The linkage assembly 6 includes a first link 61, a second link 62, and a seat connector 63. One end of the first link 61 is hinged to the middle of the backrest support 5 facing the backrest 4, and the other end of the first link 61 is hinged to one end of the mounting bracket 8. In one embodiment, the first link 61 includes two parallel first supports 611, one end of which is hinged to the backrest support 5, and the other end of which is hinged to the mounting bracket 8 via the same hinge axis. The second link 62 is located above the first link 61, one end of which is hinged to the upper end of the backrest support 5, and the other end of which is hinged to the mounting bracket 8. As a preferred configuration, one end of the second link 62 and one end of the mounting support 8 are hinged to the back of the chair back 4 via the same hinge axis. This coaxial hinge of the second link 62 and the mounting support 8 to the chair back 4 optimizes the transmission path of the driving force and improves the structural strength at the hinge point. In another embodiment, one end of the second link 62 can be hinged to the upper part of the mounting support 8. One end of the seat connector 63 is hinged to the first link 61, and the other end of the seat connector 63 is hinged to the seat 1. Initially, the seat connector 63 is inclined downwards; specifically, the hinge point between the seat connector 63 and the first link 61 is higher than the hinge point between the seat connector 63 and the seat 1.

[0031] When the seat is not reclined and the drive mechanism 7 is not activated, the mounting bracket 8 is fixed to the back of the seat back 4. The seat back bracket 5, the seat back 4, the first link 61, and the second link 62 form a four-bar linkage. In the initial state, both the first link 61 and the second link 62 are inclined upwards. Specifically, the hinge point between the first link 61 and the seat back bracket 5 is lower than the hinge point between the first link 61 and the seat back 4, and the hinge point between the second link 62 and the seat back bracket 5 is lower than the hinge point between the second link 62 and the seat back 4.

[0032] Reference Figure 2 and Figure 3 When the drive mechanism 7 is not activated, the user lies back, causing the backrest 4 to bear force. The first link 61 and the second link 62 swing forward and downward around their respective hinge points with the backrest support 5. The connecting bracket swings backward and downward around its hinge point with the seat 1. Under the action of the four-bar linkage and the seat connector 63, the backrest 4 rotates backward as a whole, while the lower part of the backrest 4 moves downward and forward relative to the backrest support 5. This makes the movement trajectory of the backrest 4 more in line with the movement trajectory of the human back, reducing the friction and upward rubbing sensation caused by the relative movement between the human body and the backrest 4.

[0033] Reference Figure 2 and Figure 4The telescopic end of the drive mechanism 7 has a telescopic rod 71, the end of which is hinged to the lower region of the back of the chair back 4. The end of the drive mechanism 7 away from the telescopic rod 71 is hinged to the mounting bracket 8. In one specific embodiment, the mounting bracket 8 includes an integrally formed connecting part 81 and a mounting part 82. One end of the connecting part 81 is hinged to the back of the chair back 4 via the same hinge axis as the second connecting rod 62. The mounting part 82 is located at the other end of the connecting part 81. A hinge part 83 extends from the end of the connecting part 81 near the mounting part 82, and the end of the drive mechanism 7 away from the telescopic rod 71 is hinged to the hinge part 83. The mounting part 82 includes two mounting rods 821, which are located on both sides of the connecting part 81. The drive mechanism 7 is located between the two mounting rods 821, and the ends of the two mounting rods 821 are hinged to one end of each of the two first rods 611.

[0034] The drive mechanism 7 is preferably an electric push rod with a self-locking function, which locks the telescopic rod 71 in a fixed position when the drive mechanism 7 is de-energized. When the user does not need lumbar support, the drive mechanism 7 is not activated, the telescopic rod 71 is locked, and the mounting bracket 8 and the drive mechanism 7 are fixed relative to the back of the chair back 4. The seat can achieve a basic reclining function by the user applying pressure to the chair back 4. When the user needs lumbar support, whether the user is sitting upright or reclining, the drive mechanism 7 can be activated to extend the telescopic rod 71 and push the lower area of ​​the chair back 4 forward to achieve the effect of lumbar support. At this time, the drive mechanism 7 can be de-energized and self-locked to keep the chair back 4 in the support position, providing the user with stable and reliable lumbar support.

[0035] To improve the working efficiency and system stability of the drive mechanism 7, when the drive mechanism 7 is in its initial, unactivated state, the triangle formed by the hinge points of the connecting part 81 and the backrest 4, the hinge point of the hinge part 83 and the drive mechanism 7, and the hinge point of the telescopic rod 71 and the backrest 4 is an obtuse triangle, with the hinge point of the hinge part 83 and the drive mechanism 7 located at the apex of the obtuse triangle. This obtuse triangle configuration allows a large component of the output thrust of the drive mechanism 7 to be directly converted into an effective torque that rotates the lower part of the backrest 4 forward when it is activated, significantly reducing starting resistance. Furthermore, when the drive mechanism 7 stops working and locks, the pressure of the user's waist on the backrest 4 attempts to force the lower part of the backrest 4 to return to its original position. This obtuse triangle configuration causes the return force, when transmitted to the self-locking system of the drive mechanism 7, to be converted more into radial pressure on the self-locking mechanism. This force distribution enhances the reliability of the self-locking mechanism, ensuring that the support position of the lower part of the backrest 4 can be securely locked after the drive mechanism 7 is powered off or shut down.

[0036] In one embodiment, the seat connector 63 includes two symmetrically arranged second support rods 631. One end of each second support rod 631 is hinged to one of the first support rods 611, and the other end is hinged to both sides of the seat frame 11. The two second support rods 631 are connected by a connecting rod 632. The hinge point between the second support rods 631 and the first support rods 611 is closer to the hinge point between the first support rods 611 and the backrest support 5, allowing the backrest 4 to have a larger downward forward adjustment range and angle to accommodate the lumbar support needs of different body postures. The two second support rods 631 and the connecting rod 632 are integrally formed, and the seat connector 63 is generally A-shaped. One end of each second support rod 631 is hinged to the two first support rods 611 through the same hinge axis. The main body of the second support rod 631 is designed as an arc protruding outwards from the seat to provide space for the user's legs and hips on both sides of the seat, preventing movement interference. In other embodiments, the two second support rods 631 may also be arranged in parallel, with the ends of the two second support rods 631 away from the first support rod 611 hinged to the middle of the seat frame 11. Optionally, the ends of the two second support rods 631 away from the first support rod 611 may also be hinged to the handrails 12 on both sides.

[0037] Reference Figure 1 and Figure 3 The chassis 2 and the backrest support 5 are rotatably connected by a hinge seat 9. One end of the hinge seat 9 is fixedly connected to the backrest support 5, and the other end of the hinge seat 9 is hinged to the chassis 2. The chassis 2 includes an upper fixed seat 21, a lower fixed seat 22, and a third connecting rod 23. The upper fixed seat 21 is fixedly connected to the bottom of the seat frame 11, and the lower fixed seat 22 is fixedly connected to the support leg 3. One end of the upper fixed seat 21 and the lower fixed seat 22 are simultaneously hinged to one end of the hinge seat 9, and the other ends of the upper fixed seat 21 and the lower fixed seat 22 are respectively hinged to both ends of the third connecting rod 23. The upper fixed seat 21, lower fixed seat 22, third link 23, and hinge seat 9 form a four-bar linkage. When the backrest support 5 drives the hinge seat 9 to rotate downwards, the upper fixed seat 21 is pulled by the hinge seat 9 and tends to move downwards and backwards. The third link 23 is forced to tilt backwards, causing the upper fixed seat 21 to move the seat frame 11 backwards. At the same time, the hinge seat 9 sinks, causing the end connecting the upper fixed seat 21 and the hinge seat 9 to sink, causing the rear end of the seat frame 11 to move downwards relative to the front end. The entire seat frame 11 is in a posture with the front end tilted upwards. The backward and downward displacement of the seat frame 11 better conforms to the natural curves of the thighs and buttocks when the human body is lying down, improving the comfort of lying down.

[0038] Reference Figure 5 and Figure 6The hinge seat 9 includes two parallel and symmetrically arranged first side plates 91 and a connecting plate 92 connecting the two first side plates 91. The two first side plates 91 and the connecting plate 92 are integrally connected or fixedly connected. The connecting plate 92 is fixed to the lower end of the chair back support 5 by bolts or welding to achieve a fixed connection between the hinge seat 9 and the chair back support 5. The upper fixed seat 21 includes two parallel and symmetrically arranged second side plates 211 and a fixed plate 212. The fixed plate 212 is fixedly connected to the lower part of the seat frame 11, and the two second side plates 211 are fixedly connected to the lower fixed seat 22 below the fixed plate 212 and located on both sides of the lower fixed seat 22. The two second side plates 211 are respectively hinged to the two first side plates 91, and the two first side plates 91 are also hinged to both sides of the lower fixed seat 22. The hinge point between the first side plate 91 and the lower fixed seat 22 is located in front of and below the hinge point between the first side plate 91 and the second side plate 211.

[0039] The upper fixed seat 21, the lower fixed seat 22, and the third connecting rod 23 enclose a receiving space. An elastic reset element 24 is provided within this space. The elastic reset element 24 allows the chair back 4 to automatically return to its original position when not under pressure. The elastic reset element 24 is preferably a tension spring. Two tension springs are arranged in parallel. One end of each tension spring is connected to the lower fixed seat 22 via a fixed shaft 25, which is fixed relative to the end of the lower fixed seat 22 near the third connecting rod 23. The other end of each tension spring is connected to the hinge seat 9 via an adjusting shaft 26. The adjusting shaft 26 passes through two first side plates 91 and is fixed relative to them. The collars at both ends of the tension spring are respectively fitted onto the fixed shaft 25 and the adjusting shaft 26. When the chair back 4 is under force, causing the hinge seat 9 to rotate backward, the hinge seat 9 stretches the tension spring by driving the adjusting shaft 26. When the chair back 4 is not under force, the tension spring, under the action of the elastic reset force, causes the chair back 4 and the chair back support 5 to return to their original position.

[0040] Two first side plates 91 are provided with adjustment slots 911 for the adjustment shaft 26 to pass through. The adjustment slots 911 are preferably waist-shaped slots. The adjustment shaft 26 passes through the adjustment slots 911 on both sides and is fixed to the two first side plates 91. The chassis 2 is provided with a force adjustment mechanism 27 for driving the adjustment shaft 26 to slide in the adjustment slots 911. By changing the distance between the adjustment shaft 26 and the hinge axis of the hinge seat 9 and the support seat through the force adjustment mechanism 27, the lever arm is adjusted to adjust the backward rebound force to adapt to users of different weights.

[0041] Reference Figure 7-9The force adjustment mechanism 27 includes a gear assembly 271, a lifting member 272, and an adjusting rod 273. The lifting member 272 is located between two tension springs. One end of the lifting member 272 is hinged to the fixed shaft 25, and the other end is hinged to the lower end of the adjusting rod 273. The upper end of the adjusting rod 273 is hinged to the adjusting shaft 26. The end of the lifting member 272 connected to the adjusting shaft 26 is lower than the end of the lifting member 272 connected to the fixed shaft 25. The gear assembly 271 is located below the lifting member 272 and is used to drive the lifting member 272 to rise or fall, thereby moving the adjusting rod 273 and causing the adjusting rod 273 to drive the adjusting shaft 26 to slide up and down within the adjusting groove 911. In one specific embodiment, the gear assembly 271 includes a first gear 274 and a second gear 275 arranged perpendicularly to each other, meshing with each other. One end of the first gear 274 has beveled teeth, and the second gear 275 has beveled teeth circumferentially. The other end of the first gear 274 is connected to an adjusting handle 276, which extends out of the chassis 2 for easy operation. An adjusting block 277 is provided at the upper end of the second gear 275, and the adjusting block 277 is fixedly connected to the lower part of the lifting member 272. The upper end of the second gear 275 is constructed with a threaded structure (not shown in the figure). The adjusting block 277 has a threaded hole that mates with the thread of the second gear 275. By rotating the adjusting handle 276, the first gear 274 drives the second gear 275 to rotate circumferentially. The circumferential rotation of the second gear 275 is converted into the lifting and lowering motion of the adjusting block 277 through the threaded structure, thereby causing the lifting member 272 to drive the adjusting shaft 26 to slide within the adjusting groove 911.

[0042] The implementation principle of a chair according to an embodiment of this application is as follows: a multi-link system consisting of a chair back 4, a chair back support 5, a first link 61, a second link 62, a mounting bracket 8, and a seat connector 63 links the chair back 4, seat 1, and chassis 2. When the user leans back, the multi-link system causes the lower part of the chair back 4 to shift downward and forward relative to the chair back support 5 while the chair back 4 rotates as a whole, providing basic lumbar support. When further lumbar support is needed, the drive mechanism 7 is activated to extend the telescopic rod 71, which pushes the lower part of the chair back 4 further forward, achieving an adjustable lumbar support effect in terms of both amplitude and force. The linkage structure consisting of the upper fixed seat 21, the lower fixed seat 22, the third link 23, and the hinge seat 9 causes the rear end of the seat frame 11 to move downward relative to the front end while the chair back 4 leans back, and the front end of the entire seat frame 11 tilts upward to conform to the natural curve of the buttocks and legs when the user is lying down. By operating the adjustment handle 276, the adjustment shaft 26 is driven to move along the length of the adjustment groove 911, locking the adjustment shaft 26 at different height positions, thereby adjusting the lever arm to adjust the reclining rebound force to accommodate users of different weights. When the seat needs to be reset, the reclining state of the backrest 4 is reset by the elastic reset member 24, and the lumbar support state of the lower part of the backrest 4 is reset by the drive mechanism 7.

[0043] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A backrest assembly, comprising a backrest (4) and a backrest support (5), said backrest support (5) being rotatably connected to the chassis (2) of a seat, characterized in that, Also includes: The first link (61) has one end hinged to the chair back support (5); Mounting support (8), one end of which is hinged to the other end of the first connecting rod (61), and the other end of which is hinged to the back of the chair back (4); The second link (62) is located above the first link (61). One end of the second link (62) is hinged to the chair back bracket (5), and the other end of the second link (62) is hinged to the mounting bracket (8). A drive mechanism (7) is provided, one end of which is hinged to the mounting support rod (821), and the other end of which has a telescopic rod (71), the end of which is hinged to the lower region of the back of the chair back (4). A seat connector (63), one end of which is hinged to the first connecting rod (61), and the other end of which is hinged to the seat (1) of the seat; The drive mechanism (7) is configured to extend the telescopic rod (71) to cause the lower region of the chair back (4) to make a forward thrusting motion relative to the chair back support (5).

2. The backrest assembly according to claim 1, characterized in that: The mounting bracket (8) includes a connecting part (81) and a mounting part (82). One end of the connecting part (81) is hinged to the back of the chair back (4), and the other end of the connecting part (81) is provided with a hinge part (83). The end of the drive mechanism (7) away from the telescopic rod (71) is hinged to the hinge part (83), and the end of the mounting part (82) away from the connecting part (81) is hinged to the first connecting rod (61).

3. The backrest assembly according to claim 2, characterized in that: The mounting part (82) includes two mounting rods (821), which are located on both sides of the connecting part (81). The hinge part (83) is located between the two mounting rods (821). The driving mechanism (7) is located between the two mounting rods (821). The first connecting rod (61) includes two first rods (611), and the ends of the two mounting rods (821) away from the connecting part (81) are respectively hinged to the two first rods (611).

4. The backrest assembly according to claim 3, characterized in that: The seat connector (63) includes two second support rods (631), one end of each second support rod (631) is hinged to the two first support rods (611), and the other end of each second support rod (631) is hinged to the seat (1) of the seat.

5. The backrest assembly according to claim 3, characterized in that: When the drive mechanism (7) is not activated, the triangle formed by the hinge point of the connecting part (81) and the backrest (4), the hinge point of the hinge part (83) and the drive mechanism (7), and the hinge point of the telescopic rod (71) and the backrest (4) is an obtuse triangle, and the hinge point of the hinge part (83) and the drive mechanism (7) is the obtuse vertex of the obtuse triangle.

6. The backrest assembly according to claim 1, characterized in that: The drive mechanism (7) is an electric push rod with a self-locking function.

7. A type of seat, characterized in that: The backrest assembly as described in any one of claims 1-6 further includes a seat (1), a base (2) and a support leg (3), wherein the base (2) is fixedly fixed below the seat (1), the support leg (3) is fixedly connected below the base (2), and the base (2) and the backrest support (5) are rotatably connected by a hinge (9).

8. The seat according to claim 7, characterized in that: The chassis (2) includes an upper fixed seat (21), a lower fixed seat (22) and a third connecting rod (23). The upper fixed seat (21) is fixedly connected to the lower part of the seat (1), and the lower fixed seat (22) is fixedly connected to the support leg (3). One end of the hinge seat (9) is hinged to one end of the upper fixed seat (21) and the lower fixed seat (22), and both ends of the third connecting rod (23) are respectively hinged to the other ends of the upper fixed seat (21) and the lower fixed seat (22).

9. The seat according to claim 8, characterized in that: The lower fixed base (22) is provided with an elastic reset member (24) and a force adjustment mechanism (27). The hinge base (9) has corresponding adjustment slots (911) on both sides. An adjustment shaft (26) is inserted through the two adjustment slots (911). One end of the elastic reset member (24) is connected to the adjustment shaft (26), and the other end of the elastic reset member (24) is connected to the lower fixed base (22). The force adjustment mechanism (27) is configured to drive the adjustment shaft (26) to move along the length direction of the adjustment slot (911) and lock it in different positions.

10. The seat according to claim 9, characterized in that: The force adjustment mechanism (27) includes a gear assembly (271), a lifting member (272), and an adjusting rod (273). The upper end of the adjusting rod (273) is connected to the adjusting shaft (26), and the lower end of the adjusting rod (273) is connected to one end of the lifting member (272). The other end of the lifting member (272) is rotatably connected to the lower fixed seat (22). The gear assembly (271) is connected to an adjusting handle (276). By rotating the adjusting handle (276), the gear assembly (271) drives the lifting member (272) to rise and fall, thereby driving the adjusting rod (273) to drive the adjusting shaft (26) to slide within the adjusting groove (911).

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