A backrest chair

Abstract

The utility model discloses a kind of backrest chairs, including seat subassembly and chair back subassembly, chair back subassembly includes waist back support subassembly and the back support frame connected in the rear end of seat subassembly, waist back support subassembly includes the back support piece in higher position and the waist support piece in lower position;Sliding seat is slidably connected on seat subassembly;One of waist support piece and back support piece is slidably connected on the sliding seat of seat subassembly through linkage support and realizes front and rear linkage, without setting sleeve mechanism or connecting rod mechanism in the rear end of waist support piece or back support piece, so that waist support piece or back support piece can move in a large range forwards and backwards, simplify seat structure, improve the backrest range of waist support piece or back support piece, guarantee seat aesthetic property.

Description

Technical Field

[0001] This utility model relates to the field of seating, and in particular to a backrest chair. Background Technology

[0002] Compared to traditional chairs with fixed backrests, chairs with backrest adjustment functions are more sought after and in demand in the market. Their backrests can move back and forth relative to the seat to accommodate diners of different body types, improving back support and seating experience.

[0003] Some seats have a single-back structure, including a back support frame and a back support member arranged in front of the back support member. In order to ensure that the back support member always fits against the back support, an adjustment mechanism is set between the back support frame and the back support member to adjust the front and rear support position of the back support member. For example, in the seat back support structure patent with announcement number CN219613424, a back support member is installed on the seat back rod (equivalent to the back support frame). A linkage mechanism such as first and second swing members and first and second connecting rods is set between the back support member and the seat back to link with the backrest, and the seat back moves back and forth by means of a torsion spring to achieve the purpose of back support.

[0004] Some chairs have a double-back structure, which includes a back support and a lumbar support arranged vertically on the back support frame. When the human back moves back and forth, in order for the lumbar support to provide follow-up support to the waist, existing chairs usually have a guide mechanism between the back support frame and the rear end of the lumbar support to adjust the forward and backward movement position of the lumbar support. For example, in the adjustable lumbar support patent with publication number CN223247863, the lumbar support is connected to a sliding member, which is slidably connected to a connecting member. The connecting member and the sliding member are a sleeve structure that fits into each other. An elastic member is provided between the connecting member and the sliding member to drive the lumbar support to move forward continuously, so as to achieve the purpose of follow-up support to the waist.

[0005] Both of the above-mentioned chair structures achieve the purpose of lumbar or back support by setting an adjustment mechanism between the back support frame and the back support component, or between the back support frame and the lumbar support. However, this design has the following shortcomings.

[0006] To avoid affecting the exterior appearance, the design dimensions of the sleeve-type sliding structure are usually relatively short, which means that the lumbar support or back support cannot move forward a large range. If the size of the adjustment mechanism is designed to be longer, although the forward movement range of the lumbar support or back support can be increased, this will cause the entire adjustment mechanism to occupy a large amount of front-to-back space on the seat. The linkage structure adjustment mechanism can lengthen the linkage to increase the forward movement range of the backrest, but when the linkage is closed, it will occupy a large amount of longitudinal space on the seat; all of these will affect the aesthetics of the seat.

[0007] The adjustment mechanism located at the rear of the lumbar support or back support takes up a certain amount of space. When the lumbar support or back support moves backward, the maximum backward movement of the lumbar support or back support can only be the front position of the adjustment mechanism. This results in insufficient backward adjustment range of the lumbar support or back support, affecting the user experience of the seat. Summary of the Invention

[0008] This utility model provides a backrest-following chair, in which one of the lumbar support or back support components is slidably connected to a sliding seat on the seat assembly, and the two components are linked together by a linkage bracket. This eliminates the need for a sleeve mechanism or linkage mechanism at the rear end of the lumbar support or back support component, allowing the lumbar support or back support component to move a wide range of distances back and forth. This simplifies the seat structure, increases the backrest-following range of the lumbar support or back support component, and ensures the aesthetics of the seat.

[0009] The technical solution of this utility model is implemented as follows: A backrest chair includes a seat assembly and a backrest assembly. The backrest assembly includes a lumbar support assembly and a back support frame connected to the rear end of the seat assembly. The lumbar support assembly includes a back support member at a higher position and a lumbar support member at a lower position. A sliding seat is slidably connected to the seat assembly. One of the back support member and the lumbar support member is disposed on the back support frame, and the other of the back support member and the lumbar support member is connected to the sliding seat through a linkage bracket. When the sliding seat slides back and forth, it can move the back support member or the lumbar support member back and forth to support the waist or back.

[0010] Preferably, the back support is mounted on the back support frame, and the waist support is connected to the sliding seat via a linkage bracket; so that when the sliding seat slides back and forth, the waist support can move back and forth in a wide range, providing close support to the waist.

[0011] Preferably, the lumbar support is rotatably connected to the linkage bracket in the front-to-back direction; when the waist tilts forward or backward, the lumbar support, which is subjected to the force of the waist, can swing back and forth and fit close to the waist; adapting to the changes in the sitter's tilting posture, it provides adaptive support for the waist.

[0012] Preferably, an elastic element is provided between the linkage bracket and the lumbar support. The elastic element acts on the lumbar support and makes the lumbar support always tend to return to its initial position. The elastic element allows the lumbar support to provide elastic support to the waist. When the waist is separated from the lumbar support, the lumbar support can rotate in the opposite direction and maintain the supported position again.

[0013] Preferably, the rotatable connection between the linkage bracket and the lumbar support is a hinge end, and the elastic element is a torsion spring located at the hinge end; the torsion spring can provide sufficient elastic force for the lumbar support while occupying a small volume, minimizing the impact on the appearance of the seat.

[0014] Preferably, the seat assembly includes a seat shell with an open upper end, a seat support member at the open end, and a sliding seat including two sliding supports that are either integral or separate from each other, which are slidably connected to the seat shell. The seat shell has through strip-shaped clearance grooves on both the left and right sides, which extend in the front-back direction. The outer end of each sliding support protrudes from the corresponding strip-shaped clearance groove and is connected to the corresponding linkage bracket. When the sliding seat slides back and forth, the strip-shaped clearance grooves can avoid the outwardly protruding part of the sliding seat, allowing the linkage bracket to move back and forth.

[0015] Preferably, the seat assembly includes a seat shell with an open upper end, a seat support member is provided at the open end, and a sliding seat is slidably connected to the seat shell; the seat support member is provided with a strip-shaped clearance groove extending forward and backward, one end of the linkage bracket is connected to the sliding seat, and the other end of the linkage bracket passes upward through the strip-shaped clearance groove and is connected to the lumbar support member or the back support member.

[0016] Preferably, the chair seat assembly is equipped with a front-to-back extending guide rail, the front-to-back length of which is greater than the front-to-back length of the sliding seat, and the sliding seat is slidably connected to the guide rail in the front-to-back direction; the linkage bracket is symmetrically connected to the sliding seat on the left and right and connected to the corresponding position of the lumbar support.

[0017] Preferably, the seat assembly is equipped with a drive unit, which is directly or indirectly connected to the sliding seat to drive the sliding seat to slide in the front-back direction, so that the lumbar support or back support can actively follow the back.

[0018] Preferably, the driving element is a gas spring or mechanical spring that drives the sliding block to always have a forward tendency; or, the driving element is an electric push rod that drives the sliding block to slide back and forth.

[0019] Preferably, the back support frame is fixedly connected to the rear end of the seat assembly; or, the back support frame is rotatably connected to the rear end of the seat assembly in the front-back direction. When the back support frame is fixed to the rear end of the seat assembly, the lumbar support or back support connected thereto can be kept fixed. When the back support frame is rotatably connected to the rear end of the seat assembly, the lumbar support or back support connected thereto can be rotated back and forth to adapt to the tilting motion of the sitter's lower back and provide support for the lower back.

[0020] Preferably, the chair seat assembly includes a chair seat and a chassis disposed at the bottom of the chair seat. The chassis includes a base, and a back connector is rotatably connected to the base in the front-back direction. The back connector is fixedly connected to the back support frame, so that the back support frame can rotate back and forth.

[0021] Preferably, the linkage support is a rigid sheet or rod structure.

[0022] Preferably, the linkage bracket includes a fixed seat connected to the sliding seat and a lifting seat slidably connected to the fixed seat in the longitudinal direction. The lifting seat is connected to the lumbar support or back support. The lifting seat can slide in the longitudinal direction and stop at a predetermined position to adjust the height support position of the lumbar support or back support. This allows the user to adjust the lumbar support according to their own body shape or usage needs, making it more versatile.

[0023] The beneficial effects of this utility model, which adopts the above technical solution, are as follows: This utility model connects one of the lumbar and back support components to a sliding seat on the chair seat assembly via a linkage bracket, eliminating the need for space-consuming sleeve or linkage mechanisms at the rear end of the lumbar or back support component. This design is equivalent to switching the position of the back-following mechanism of the linkage lumbar or back support component from the back support frame to the chair seat assembly, saving space, reducing the abruptness of the rear end mechanism of the lumbar or back support component, and allowing the lumbar or back support component to move a wide range of distances back and forth, thus improving the back-following support effect.

[0024] The lumbar support is connected to the sliding seat via a linkage bracket, while the back support is mounted on the back support frame. This design allows the lumbar support to be adjusted independently of the back support, meeting various user needs. For example, if the user wants simultaneous support for the lower back, they can pull the lumbar support backward to align it with the back support. When the user moves forward, they can pull the lumbar support forward, extending it beyond the front of the back support to provide support only for the lower back, while the back and chair back remain separate. This allows the user to precisely and independently support their lower back according to their needs, or simultaneously support their lower back, enhancing versatility and improving the overall user experience.

[0025] The back support frame can be rotated forward and backward and connected to the rear end of the seat assembly, giving the back support a forward and backward tilting function. The lumbar support can be rotated forward and backward and connected to the linkage bracket. When the back support is subjected to a backward leaning force and tilts forward and backward, the sitter's waist will also tilt in sync. At this time, the lumbar support is simultaneously subjected to the force of the waist and rotates backward to fit the waist, so that the sitter's waist and back can be supported in place when tilting forward and backward, avoiding the phenomenon of waist slippage. Attached Figure Description

[0026] Figure 1 This is a schematic diagram showing the sliding seat moving the waist support forward via the linkage bracket. Figure 2 This is a schematic diagram showing the sliding seat moving the waist support component backward via the linkage bracket. Figure 3 This is a schematic diagram showing the lumbar support component moving forward and backward and up and down from a side view. Figure 4This is a schematic diagram showing the lumbar support and back support rotating backward from a side view. Figure 5 This is a schematic diagram of the connection of the sliding seat inside the housing; Figure 6 A schematic diagram showing how the sliding seat moves forward via a traction gas spring; Figure 7 A schematic diagram showing the synchronous forward movement of two sliding supports via corresponding push-pull gas springs; Figure 8 This is a schematic diagram showing the connection between the back support and the sliding seat via a linkage bracket in Example 2. Figure 9 This is a schematic diagram of the connection between a single linkage bracket and the waist support in Example 3; Figure 10 This is a schematic diagram of the symmetrically arranged linkage brackets and waist support members connected in Example 3; Figure 11 This is a side view of the backrest chair in Example 3; Figure 12 This is a diagram showing the positions of a single linkage bracket and symmetrical linkage brackets within the housing in Example 3. Figure 13 This is a side view of the guide rail outside the seat assembly and the linkage bracket slidingly connected in Embodiment 4; The reference numerals in the attached figures are as follows: 1-seat assembly, 1a-chassis, 1b-backrest connector, 11-seat support, 12-sliding seat, 12a-connecting seat, 13-strip clearance groove, 14-guide groove, 15-guide rail, 16-sliding support seat, 17-support arm, 18-rolling element, 121-sliding support, 2-backrest assembly, 21-backrest support, 22-lumbar support, 23-backrest support frame, 24-linkage bracket, 241-fixed seat, 242-lifting seat, 3-push-pull gas spring, 3a-traction gas spring, 31-control switch, 32-self-locking device. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0028] Many specific details are set forth in the following description in order to provide 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 scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0029] This utility model has multiple embodiments, and the specific implementation methods are as follows: Example 1: As Figure 1-7 As shown, this embodiment provides a backrest chair, including a seat assembly 1 and a backrest assembly 2. The backrest assembly 2 includes a lumbar support assembly and a back support frame 23 connected to the rear end of the seat assembly 1. The lumbar support assembly includes a back support member 21 at a higher position and a lumbar support member 22 at a lower position. A sliding seat 12 is slidably connected to the seat assembly 1. One of the back support member 21 and the lumbar support member 22 is disposed on the back support frame 23, and the other of the back support member 21 and the lumbar support member 22 is connected to the sliding seat 12 through a linkage bracket 24. The sliding seat 12 disposed on the seat assembly enables... The lumbar support 22 or the back support 21 are linked together by the linkage bracket 24, which is equivalent to changing the position of the original back-tracking mechanism (i.e., the linkage mechanism or sleeve mechanism mentioned in the background art) from the rear end of the lumbar support 22 or the back support 21 to the seat assembly. This avoids the back-tracking mechanism occupying a large space at the rear end of the lumbar and back support assembly, and widens the sliding range of the lumbar support 22 or the back support 21, making the seat look more concise and beautiful. When the sliding seat 12 slides back and forth, it can link one of the back support 21 and the lumbar support 22 to move back and forth to support the waist or back.

[0030] Furthermore, such as Figure 1-3 As shown, in this embodiment, the back support 21 is mounted on the back support frame 23, and the lumbar support 22 is connected to the sliding seat 12 via a linkage bracket 24. The back support 21 can be fixed to the back support frame 23, or it can be slidably connected to the back support frame 23 longitudinally to adjust the height and support position of the back support 21. When the sliding seat 12 slides back and forth, the lumbar support 22 can move back and forth in a wide range to provide close support for the waist. Specifically, when the sliding seat 12 slides back and forth, the lumbar support 22 can move back and forth to support the waist, while the back support 21 is on the back support frame 23, thus satisfying the needs of the sitter. Different usage needs; for example, when the occupant moves forward and only needs to support the lower back, the lumbar support 22 can be moved forward to a more forward position, so that the position of the lumbar support 22 is offset from the position of the back support 21, and the back is separated from the back support 23. When the occupant moves backward, the lumbar support 22 can be moved backward to a more rearward position, so that the position of the lumbar support 22 corresponds to the position of the back support 21. The lumbar and back supports can simultaneously support the occupant's lower back. This design allows the lumbar support 22 to be independently adjusted in front and back relative to the back support 21, making it more practical and effectively improving the user experience of the chair.

[0031] Furthermore, such as Figure 4As shown, in this embodiment, the lumbar support 22 is rotatably connected to the linkage bracket 24 in the front-back direction to adapt to changes in the position of the waist. Specifically, when the upper body of the sitter leans back, it will also cause the waist to change in angle and position in the front-back direction. Therefore, when the waist leans back and forth, the lumbar support 22, which is subjected to the force of the waist, can swing back and forth and fit tightly against the waist. It adapts to the changes in the sitter's leaning posture and provides adaptive support for the waist.

[0032] Furthermore, in this embodiment, an elastic element is provided between the linkage bracket 24 and the lumbar support member 22. The elastic element acts on the lumbar support member 22, and makes the lumbar support member 22 always tend to return to its initial position. The elastic element allows the lumbar support member 22 to provide elastic support to the waist. When the waist separates from the lumbar support member 22, the lumbar support member 22 can rotate in the opposite direction and maintain the supported position again. The elastic element can be a tension spring, compression spring, or other components that can generate elasticity after being subjected to force. However, since elastic elements such as tension springs require a certain amount of space and are easily exposed on the lumbar support member 22, the linkage bracket in this embodiment... The hinge end is the rotatable connection between the frame 24 and the lumbar support 22. The elastic element is a torsion spring (not shown) located at the hinge end. For example, the linkage bracket 24 and the lumbar support 22 are rotatably connected by a rotating shaft. The torsion spring can be sleeved on the rotating shaft. The torsion spring includes a helical part and two torsion arms connected to the helical part. One torsion arm acts on the lumbar support 22, and the other torsion arm acts on the linkage bracket 24. When the lumbar support 22 rotates, the torsion spring generates elasticity, which can provide sufficient elastic force for the lumbar support 22. At the same time, it occupies a small volume and minimizes the impact on the appearance of the seat.

[0033] Furthermore, such as Figure 5 As shown, in this embodiment, the seat assembly 1 includes a seat shell with an open upper end. A seat support 11 is provided at the open end. The seat support 11 is usually a seat plate covered with soft padding and matching the open end, or it can be a mesh fabric stretched at the open end. The seat shell and the seat support 11 constitute the seat. In this embodiment, the seat support 11 is used as the seat plate for explanation. To prevent the seat plate from deforming under downward pressure, sliding support seats 16 are symmetrically provided on the sliding seat 12. The sliding support seats 16 are POM sliders protruding from the upper and lower ends of the sliding seat 12. POM is polyoxymethylene engineering plastic, which has a smooth upper surface and a lower surface. The upper and lower surfaces are respectively attached to the bottom end of the seat plate and the seat shell, ensuring that the sliding seat 12 can slide back and forth while supporting the seat plate to prevent its deformation. At the same time, to prevent the symmetrically arranged sliding support seats 16 from swaying during sliding, the seat plate and the seat shell are provided with corresponding guide grooves 14. The guide grooves 14 are composed of two ribs spaced apart from left to right. The sliding support seats 16 are located in the guide grooves 14.

[0034] Furthermore, to improve the smoothness of the sliding seat 12's forward and backward movement, a support frame is symmetrically provided on the sliding seat 12. The support frame includes symmetrical support arm assemblies, each including a support arm 17 that extends obliquely and is symmetrically arranged front and back. A rolling element 18 is rotatably connected to the top of the support arm 17. To prevent the symmetrically arranged rolling elements 18 from shifting during rolling, the seat plate and seat shell are also provided with corresponding guide grooves 14, and the rolling elements 18 are located in the guide grooves 14. The guide grooves 14 are composed of two ribs spaced apart from each other. The rolling elements 18 can be any of the following: rollers, gears, rolling bearings, or balls. The rolling elements 18 at the upper and lower ends of the support frame contact the seat plate and seat shell respectively, so that the sliding seat 12 and the chair seat indirectly form rolling contact, thereby improving the smoothness of the sliding seat 12's forward and backward movement. Furthermore, the sliding seat 12 includes two sliding supports 121 that are connected as one piece or separate from each other. The sliding supports 121 are slidably connected in the seat housing. The left and right sides of the seat housing are provided with through strip-shaped clearance grooves 13. The strip-shaped clearance grooves 13 extend in the front-back direction. The outer end of each sliding support 121 passes through the corresponding strip-shaped clearance groove 13 and is connected to the corresponding linkage bracket 24. When the sliding seat 12 slides back and forth, the strip-shaped clearance grooves 13 can avoid the outwardly protruding part of the sliding seat 12, so that the linkage bracket 24 moves back and forth.

[0035] Furthermore, to enable the lumbar support component 22 to provide automatic lumbar support, a driving component is installed on the seat assembly 1 in this embodiment. The driving component is directly or indirectly connected to the sliding seat 12 to drive the sliding seat 12 to slide in the front-back direction. This allows the lumbar support component 22 or the back support component 21 to actively provide follow-up support without manual adjustment, thus improving the back support experience. In this embodiment, the driving component is a gas spring or mechanical spring that drives the sliding seat 12 to always have a forward tendency. Figure 5 As shown, the gas spring can be a push-pull gas spring 3 disposed between the rear end of the chair seat and the sliding seat 12, and the push-pull gas spring 3 has a piston rod that always maintains an extended tendency; as Figure 6As shown, a traction gas spring 3a can also be installed between the front end of the chair seat and the sliding seat 12. The traction gas spring 3a has a piston rod that always maintains a retracted tendency. To control the locking and unlocking of the sliding seat 12, the self-locking device 32 of the gas spring can be connected to a pull cable, and the other end of the pull cable can be connected to a control switch 31. The self-locking device 32 is existing technology and will not be described in detail here. The control switch 31 can be an adjustable wrench or button installed outside the chair seat. The mechanical spring can be a compression spring (not shown) between the rear end of the chair seat and the sliding seat 12, or a tension spring (not shown) between the front end of the chair seat and the sliding seat 12. Based on this, a stop mechanism (not shown) can be installed between the chair seat and the sliding seat 12 to lock and unlock the sliding seat 12. The shifting mechanism includes multiple shifting slots spaced back and forth on the seat, and a locking member movably connected to the sliding seat 12. An elastic element is also provided between the locking member and the sliding seat 12, ensuring the locking member always tends to engage with the shifting slot. The locking member is connected to a pull cable, which is connected to the control switch 31. After the sliding seat 12 slides into position, the locking member actively engages with the corresponding shifting slot to create a locking effect. To unlock, the control switch 31 can be used to pull the pull cable, causing the locking member to disengage from the corresponding shifting slot. When the occupant's back moves forward, a gas spring or mechanical spring can push the sliding seat 12 forward and into contact with the back. Alternatively, the driving component is an electric push rod (not shown) that drives the sliding seat 12 to slide back and forth. The occupant can control the extension and retraction of the electric push rod via a button electrically connected to the electric push rod and located on the seat, providing automatic lumbar support.

[0036] Furthermore, in this embodiment, if the two sliding supports 121 are connected as one unit, the driving component can act on the middle position of the sliding support 12; such as Figure 7 As shown, if the two sliding supports 121 are separated from each other, a corresponding driving component can be set between each sliding support 121 and the seat to make the two sliding supports 121 move forward synchronously. Taking the driving component as a push-pull gas spring 3 as an example, the two push-pull gas springs 3 can act on the corresponding sliding supports 121. In order to realize the linkage of the two push-pull gas springs 3, the pull wires on the two push-pull gas springs 3 can be connected to the same control switch 31, so that the control switch 31 can synchronously control the self-locking device 32 on the two push-pull gas springs 3, so that the two sliding supports 121 move back and forth synchronously.

[0037] Furthermore, to increase the range of backward sliding of the waist support 22 or back support 21 linked to the sliding seat 12, in this embodiment, the connection position of the linkage bracket 24 to the sliding seat 12 is further back than the connection position of the front end of the driving component to the sliding seat 12. Taking the driving component as a push-pull gas spring 3 as an example, the gas spring includes a cylinder and a piston rod slidably connected to the cylinder. The piston rod is connected to the sliding seat 12. If the connection position of the piston rod to the sliding seat 12 and the connection position of the linkage bracket 24 to the sliding seat 12 correspond, then when the piston rod is fully retracted, the sliding seat 12 is at the front end of the cylinder and cannot move further backward. If the connection position of the linkage bracket 24 to the sliding seat 12 is further back than the connection position of the piston rod to the sliding seat 12, that is, if the piston rod... The connection position of the sliding seat 12 is further forward and extends beyond the connection position of the linkage bracket 24 and the sliding seat 12. When the piston rod retracts, the sliding seat 12 obviously moves backward beyond the head end of the cylinder, which further expands the backward movement range of the backrest 2. Specifically, in order to make the connection position of the piston rod and the sliding seat 12 further forward and extend beyond the connection position of the linkage bracket 24 and the sliding seat 12, the sliding seat 12 also includes a forward-protruding connecting seat 12a. The front end of the piston rod is connected to the forward-protruding connecting seat 12a. In order to make the sliding seat 12 avoid the elastic drive member, the elastic drive member and the sliding seat 12 can be staggered vertically, or a through hole that runs through the front and back and allows the elastic drive member to pass through can be provided on the sliding seat 12; so that the connection position of the elastic drive member and the sliding seat 12 is further forward.

[0038] Furthermore, the sliding seat 12 can also be configured as a forward-protruding bow-shaped component (not shown), with the left and right ends of the bow-shaped component used to connect with the linkage bracket 24, and the body of the bow-shaped component connected to the front end of the elastic drive component, which can also make the connection position between the elastic drive component and the sliding seat 12 more forward.

[0039] Furthermore, in this embodiment, the back support frame 23 can be fixedly connected to the rear end of the seat assembly 1, so that the lumbar support member 22 or the back support member 21 connected thereto remains fixed; or, the back support frame 23 can be rotatably connected to the rear end of the seat assembly 1 in the front-back direction, so that the lumbar support member 22 or the back support member 21 connected thereto can rotate back and forth to adapt to the tilting motion of the sitter's lower back and provide support for the lower back; specifically, as Figure 4 As shown, the chair seat assembly 1 includes a chair seat and a chassis 1a disposed at the bottom of the chair seat. The chassis 1a includes a base, and the base is provided with a seat connector connected to the chair seat and a back connector 1b rotatably connected in the front-back direction. The back connector 1b is fixedly connected to the back support frame 23, so that the back support frame 23 can rotate back and forth.

[0040] Furthermore, to ensure the structural stability and non-deformation of the linkage bracket 24, the linkage bracket 24 in this embodiment is a rigid sheet-like or rod-like structure; or, to facilitate adjustment of the longitudinal support position of the waist support member 22, such as Figure 3As shown, the linkage bracket 24 in this embodiment can also be a lifting structure. The linkage bracket 24 includes a fixed base 241 connected to the sliding base 12 and a lifting base 242 slidably connected to the fixed base 241 in the longitudinal direction. The lifting base 242 is connected to the lumbar support member 22 or the back support member 21. The lifting base 242 can slide in the longitudinal direction and stop at a predetermined position to adjust the height support position of the lumbar support member 22 or the back support member 21. To ensure that the lifting base 242 can stop at the corresponding position, a movable locking member (not shown) and multiple vertically spaced locking slots (not shown) can be provided between the fixed base 241 and the lifting base 241. The locking slots are usually provided on the fixed base 241, and the locking member is usually provided on the lifting base 242. After the lifting base 242 is raised or lowered to the correct position, the locking member engages with the corresponding locking hole, so that the lumbar support member 22 is kept in the correct position. This allows the user to adjust the lumbar support member 22 according to their body shape or usage needs, making it more versatile.

[0041] Example 2: As Figure 8 As shown, the difference from the above embodiment is that in this embodiment, the back support 21 is connected to the linkage bracket 24, while the lumbar support 21 is connected to the back support frame 23. Compared with embodiment 1, in this embodiment, the back support frame 23 is connected to the lower lumbar support 22, so the longitudinal length of the back support frame 23 is shorter. The linkage bracket 24 is longer and is connected to the upper back support 21. When the sliding seat 12 slides back and forth, it can move the back support 23 back and forth, so that the back support 21 is close to the back, while the lumbar support 22 is not affected by the linkage of the sliding seat 12, so that the back support 21 can be independently adjusted in front and back position relative to the lumbar support 22 to meet the sitting needs of the person sitting.

[0042] Example 3: As Figure 9-12 As shown, the difference from the above embodiment is that in this embodiment, the front-to-back extending strip-shaped clearance groove 13 is provided on the seat support 11, one end of the linkage bracket 24 is connected to the sliding seat 12, and the other end of the linkage bracket 24 passes upward through the strip-shaped clearance groove 13 and is connected to the waist support 22 or the back support 21; specifically, the linkage bracket 24 can be a single unit, and the strip-shaped clearance groove 11 can also be a single unit. The single strip-shaped clearance groove 13 is provided in the middle position of the seat support 11, and the linkage bracket 24 passes through the single strip-shaped clearance groove 13 and is connected to the middle of the waist support 22 to form a linkage; or, the linkage bracket 24 is symmetrically connected to the sliding seat 11 on the left and right, and the strip-shaped clearance groove 13 is also correspondingly provided on the seat support 11; the corresponding linkage bracket 24 passes through the corresponding strip-shaped clearance groove 13 and is connected to the waist support 22, making the connection between the waist support 22 and the linkage bracket 24 more stable, and also achieving the effect of front-to-back linkage between the waist support 22 and the sliding seat 12.

[0043] Example 4: Figure 13As shown, unlike the above embodiments, in this embodiment, the sliding seat 12 is installed outside the chair seat. Specifically, a guide rail 15 extending forward and backward is installed outside the chair seat assembly 1. The forward and backward length of the guide rail 15 is greater than the forward and backward length of the sliding seat 12, providing guidance for the forward and backward sliding of the sliding seat 12. The sliding seat 12 is slidably connected to the guide rail 15 in the forward and backward direction. There are many sliding connection methods. For example, a guide groove that runs forward and backward can be provided on the sliding seat 12. The cross-sectional shape of the guide groove matches the cross-sectional shape of the guide rail 15. The guide rail 15 is inserted into the guide groove, allowing the sliding seat 12 to slide smoothly. It is connected to the guide rail 15; or, the guide rail 15 may be provided with a guide groove extending forward and backward, and the sliding seat 12 is slidably connected to the guide groove; in this embodiment, the guide rail 15 is arranged symmetrically on the outside of the seat assembly 1, specifically, it is arranged at the bottom of the seat. The sliding seat 12 includes two sliding supports 121 that are connected as one piece or separate from each other. The two sliding supports 121 are slidably connected to the corresponding guide rail 15. The linkage bracket 24 is symmetrically connected to the sliding seat 12 and connected to the corresponding position of the lumbar support 22; it can also realize the forward and backward linkage effect of the lumbar support 22.

[0044] Furthermore, to facilitate the control and locking of the sliding seat 12, a locking mechanism can be provided between the guide rail 15 and the sliding seat 12. For example, multiple locking holes spaced back and forth can be provided on the guide rail 15, and a movable locking pin can be connected to the sliding seat 12. When the sliding seat 12 slides to the predetermined position, the locking pin is controlled to pass into the corresponding locking hole to lock the position of the waist support 22 or back support 21 that has slid into place. When unlocking is required, the locking pin can be pulled out to achieve the locking and unlocking of the front and rear positions of the waist support 22 or back support 21.

[0045] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A backrest chair, characterized in that, The chair includes a seat assembly (1) and a backrest assembly (2). The backrest assembly (2) includes a lumbar support assembly and a back support frame (23) connected to the rear end of the seat assembly (1). The lumbar support assembly includes a back support member (21) at a higher position and a lumbar support member (22) at a lower position. A sliding seat (12) is slidably connected to the seat assembly (1). One of the back support member (21) and the lumbar support member (22) is disposed on the back support frame (23), and the other of the back support member (21) and the lumbar support member (22) is connected to the sliding seat (12) through a linkage bracket (24). When the sliding seat (12) slides back and forth, it can move the back support member (21) or the lumbar support member (22) back and forth to support the waist or back.

2. The backrest chair according to claim 1, characterized in that: The back support (21) is mounted on the back support frame (23), and the waist support (22) is connected to the sliding seat (12) through the linkage bracket (24).

3. The backrest chair according to claim 2, characterized in that: The lumbar support (22) is rotatably connected to the linkage bracket (24) in the front-back direction; when the waist tilts back and forth, the lumbar support (22) subjected to the force of the waist can swing back and forth and fit tightly against the waist.

4. The backrest chair according to claim 3, characterized in that: An elastic element is provided between the linkage bracket (24) and the waist support (22). The elastic element acts on the waist support (22) and makes the waist support (22) always tend to return to its initial position.

5. The backrest chair according to claim 4, characterized in that: The hinge end is the rotating connection between the linkage bracket (24) and the waist support (22), and the elastic element is a torsion spring set at the hinge end.

6. The backrest chair according to claim 1, characterized in that: The seat assembly (1) includes a seat shell with an open top, and a seat support (11) is provided at the open top. The sliding seat (12) includes two sliding supports (121) that are connected as one piece or separate from each other. The sliding supports (121) are slidably connected in the seat shell. The left and right sides of the seat shell are provided with through strip-shaped clearance grooves (13). The strip-shaped clearance grooves (13) extend in the front and back direction. The outer end of each sliding support (121) passes through the corresponding strip-shaped clearance groove (13) and is connected to the corresponding linkage bracket (24).

7. The backrest chair according to claim 1, characterized in that: The seat assembly (1) includes a seat shell with an open top, and a seat support (11) is provided at the open top. A sliding seat (12) is slidably connected to the seat shell. The seat support (11) is provided with a strip-shaped clearance groove (13) extending forward and backward. One end of the linkage bracket (24) is connected to the sliding seat (12), and the other end of the linkage bracket (24) passes upward through the strip-shaped clearance groove (13) and is connected to the waist support (22) or the back support (21).

8. The backrest chair according to claim 1, characterized in that: The chair seat assembly (1) is equipped with a front-to-back extending guide rail (15). The front-to-back length of the guide rail (15) is greater than the front-to-back length of the sliding seat (12). The sliding seat (12) is slidably connected to the guide rail (15) in the front-to-back direction. The linkage bracket (24) is symmetrically connected to the sliding seat (12) and connected to the corresponding position of the lumbar support (22).

9. The backrest chair according to claim 1, characterized in that: A drive unit is installed on the seat assembly (1), which is directly or indirectly connected to the sliding seat (12) to drive the sliding seat (12) to slide in the front-back direction.

10. The backrest chair according to claim 9, characterized in that: The driving element is a gas spring or mechanical spring that drives the sliding seat (12) to always have a forward tendency; or, the driving element is an electric push rod that drives the sliding seat (12) to slide back and forth.

11. The backrest chair according to claim 1, characterized in that: The back support frame (23) is fixedly connected to the rear end of the seat assembly (1); or the back support frame (23) is rotatably connected to the rear end of the seat assembly (1) in the front-back direction.

12. The backrest chair according to claim 11, characterized in that: The chair seat assembly (1) includes a chair seat and a chassis (1a) disposed at the bottom of the chair seat. The chassis (1a) includes a base, and a back connector (1b) is rotatably connected to the base in the front-back direction. The back connector (1b) is fixedly connected to the back support frame (23), so that the back support frame (23) can rotate back and forth.

13. The backrest chair according to claim 1, characterized in that: The linkage support (24) is a rigid sheet or rod structure.

14. The backrest chair according to claim 1, characterized in that: The linkage bracket (24) includes a fixed seat (241) connected to the sliding seat (12) and a lifting seat (242) slidably connected to the fixed seat (241) in the longitudinal direction. The lifting seat (242) is connected to the waist support (22) or the back support (21). The lifting seat (242) can slide in the longitudinal direction and stop at a predetermined position to adjust the height support position of the waist support (22) or the back support (21).

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