Chair back assembly

Abstract

The utility model provides a chair back assembly, which comprises a back supporting assembly, a backrest supporting assembly and a backrest supporting assembly, the back chasing mechanism comprises a connecting rod assembly and a first elastic piece; the connecting rod assembly comprises an upper connecting rod and a lower connecting rod; one of the rear ends of the upper connecting rod and the lower connecting rod is in sliding connection with the back bracket and the other is rotationally connected with the back bracket; the first elastic piece acts on the upper connecting rod or the lower connecting rod which is in sliding connection with the back bracket; a chair back translation mechanism is connected between the front ends of the upper connecting rod and the lower connecting rod and the backrest; the chair back translation mechanism comprises a first rod piece and a second rod piece, a lower hinge point of the first rod piece is hinged with a rear hinge point of the second rod piece, and an upper hinge point of the first rod piece is hinged with a third rod piece; the front end of the third rod piece and the front hinge point of the second rod piece are hinged with the backrest; the first rod piece, the second rod piece, the third rod piece and the backrest form a four-connecting-rod mechanism; and when the back of a user is subjected to back-chasing elastic support, the mechanical structure is simple, and the use is convenient.

Description

Technical Field

[0001] The utility model relates to the field of seats, and particularly relates to a backrest assembly. Background Art

[0002] With the acceleration of the modern life rhythm and the development of informatization, more and more people need to sit on seats for a long time. Seats with a backtracking function have emerged as the times require, which can effectively support the back and waist and relieve the fatigue of the back and waist muscles. However, the existing backtracking chairs on the market have problems of complex mechanical structures and inconvenient use.

[0003] In the utility model patent with the Chinese patent publication number CN220800559U, a seat with a linkage backtracking mechanism is disclosed. It includes a bottom plate fixedly connected above the base, a mounting plate fixedly connected to install a seat cushion, and a backrest assembly. The mounting plate is arranged above the bottom plate through a scissor lift assembly. The lower end of the backrest assembly is pivotally connected to the rear side of the bottom plate. The movable end of the scissor assembly is connected to the backrest assembly through a connecting rod. When the mounting plate sinks relative to the bottom plate based on the scissor assembly, the backrest assembly moves forward along its pivot axis. An elastic support rod is connected to the backrest assembly or the scissor assembly or the connecting rod, and the elastic support rod is used to drive the mounting plate to lift relative to the bottom plate and the backrest assembly to move backward along its pivot axis. However, the above-mentioned linkage backtracking mechanism is relatively complex in structure, has many components, and has a high manufacturing and installation cost. Moreover, the linkage backtracking mechanism will cause the position of the backrest to change with the height of the seat surface, which is inconvenient for short people or children to use. The change in the height of the seat surface may especially have an adverse impact on the sitting posture of children. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the utility model is to provide a backrest assembly. Through the mutual cooperation of a connecting rod assembly, a sliding structure and an elastic member, the seat backrest moves back and forth, and the angle of the backrest deflecting back and forth is kept unchanged through a four-bar linkage mechanism, realizing the backtracking function of the backrest. Its mechanical structure is simple and easy to use. The change in the position of the backrest will not change the height of the seat surface, and it is suitable for people of different heights.

[0005] The technical solution of the utility model is realized as follows:

[0006] A backrest assembly, comprising:

[0007] A back support assembly, including a back bracket and a backrest;

[0008] The backrest following mechanism includes a connecting rod assembly and a first elastic member; the connecting rod assembly includes an upper connecting rod and a lower connecting rod; one of the rear ends of the upper connecting rod and the lower connecting rod is slidably connected to the backrest bracket, and the other is rotatably connected to the backrest bracket; the first elastic member acts on the upper connecting rod or the lower connecting rod that is slidably connected to the backrest bracket; a backrest translation mechanism is connected between the front ends of the upper connecting rod and the lower connecting rod and the backrest; the backrest translation mechanism includes a first rod connected to the front end of the upper connecting rod and a second rod connected to the front end of the lower connecting rod. There are an upper hinge point and a lower hinge point spaced up and down on the first rod, and a front hinge point and a rear hinge point spaced front and rear on the second rod. The lower hinge point of the first rod is hinged to the rear hinge point of the second rod, and the upper hinge point of the first rod is hinged to a third rod; the front end of the third rod and the front hinge point of the second rod are both hinged to the backrest; the first rod, the second rod, the third rod and the backrest form a four-bar linkage mechanism;

[0009] The backrest assembly is divided into a following mode and a reset mode; in the following mode, the first elastic member acts on the corresponding connecting rod in the connecting rod assembly, causing the upper connecting rod and the lower connecting rod to extend forward, and the backrest is in a forward position, so as to provide elastic following support for the user's back; in the reset mode, under the action of an external force in the backward direction, the backrest causes the upper connecting rod and the lower connecting rod to retract backward, and promotes the corresponding connecting rod in the connecting rod assembly to slide on the backrest bracket, and then the backrest moves closer to the backrest bracket, increasing the seat space to meet the usage requirements of different users; and the backrest is always kept from deflecting back and forth under the action of the backrest translation mechanism, ensuring that the angle of the backrest supporting the back remains unchanged.

[0010] Preferably, the backrest includes a backrest body and a mounting seat. The front end of the third rod and the front hinge point of the second rod are both hinged to the mounting seat; the connection between the backrest body and the mounting seat is detachable. After disassembly, the volume of the backrest assembly is greatly reduced, facilitating its transportation.

[0011] Preferably, a connection seat for cooperating with the mounting seat is connected to the reverse side of the backrest body. The backrest body is connected to the mounting seat through the connection seat, which can avoid the problem of difficult disassembly and assembly caused by directly mounting the backrest body on the backrest translation mechanism, facilitating the user to disassemble and install; at the same time, the occupied space of the backrest assembly after disassembly is small, facilitating transportation.

[0012] Preferably, an installation groove for cooperating with the mounting seat is provided on the reverse side of the connection seat. A buckle is provided at the lower end of the installation groove, and a baffle is provided at the upper end of the installation groove; when the connection seat slides to the lower end of the mounting seat through the installation groove, the buckle catches the lower end of the mounting seat and, together with the upper baffle, fixes the connection seat; when disassembling, the buckle is toggled to release the fixation between the connection seat and the mounting seat, and the connection seat slides out of the mounting seat along the installation groove. The buckle enables disassembly and assembly without professional tools, further simplifying the disassembly and assembly steps, allowing the user to disassemble and assemble the backrest by himself, and improving the user experience.

[0013] Preferably, a sliding groove is formed on the back support; a slider is fitted in the sliding groove, and one of the rear ends of the upper connecting rod and the rear end of the lower connecting rod is hinged to the slider so that its rear end can slide along the sliding groove, thereby realizing the sliding connection between one of the rear ends of the upper connecting rod and the rear end of the lower connecting rod and the back support; the sliding groove formed inside the back support reduces the volume of the backrest assembly, making the backrest structure more compact and meeting the user's usage requirements in a narrow space.

[0014] Preferably, the first elastic member is a tension spring; a groove is formed on the back surface of the back support, and the groove communicates with the sliding groove, and the tension spring is installed in the groove; the rear end of the upper connecting rod is hinged to the upper end of the back support, and the rear end of the lower connecting rod is hinged to the slider; the upper end of the tension spring is connected to the upper end of the back support, and the lower end of the tension spring is connected to the slider; in the chasing-back mode, the tension spring pulls the slider to make the connecting rod assembly extend forward; in the reset mode, a backward force acts on the backrest to stretch the tension spring, causing the slider and the rear end of the lower connecting rod to move downward, prompting the connecting rod assembly to retract backward; enabling the chasing-back mechanism to provide elastic support for the user's back and adjust the position of the backrest according to the user's sitting posture.

[0015] Preferably, a pin plate is connected to the slider, and a plurality of pin holes arranged vertically are provided on the pin plate; a pin is connected to the back support, and a knob is fixed on the pin;

[0016] The position of the slider moving up and down is adjusted by controlling the pin to insert into the pin holes at different positions through the knob, thereby adjusting and fixing the position of the backrest; when the pin is pulled out of the pin hole, the connecting rod assembly can move freely, prompting the backrest to move forward for chasing-back; the pin is inserted into and pulled out of the pin holes at different positions, enabling the seat to fix the backrest at different positions according to the user's needs, meeting the different usage requirements of the user.

[0017] Preferably, a second elastic member is connected between the back support and the pin or the knob; a boss is fixedly connected to the back surface of the back support, and a through hole matching the pin is formed in the center of the boss; adjacent first and second guide grooves are provided at opposite positions on the side surface of the boss, the first guide groove is shallower than the second guide groove, the first guide groove and the second guide groove are connected by a slope, and a positioning protrusion is provided on the slope; the first guide groove, the second guide groove cooperate with guide blocks provided at opposite positions on the inner side of the knob;

[0018] The knob is rotated to switch the guide block between the first guide groove and the second guide groove; when the knob is rotated to switch the position of the guide block from the second guide groove to the first guide groove, the guide block passes through the positioning protrusion, and the elastic force of the second elastic member presses the guide block into the first guide groove, pulling the pin out of the pin hole; when the knob is rotated to switch the position of the guide block from the first guide groove to the second guide groove, the guide block passes through the positioning protrusion, the second elastic member deforms and always acts on the pin or the knob, pressing the guide block into the second guide groove, making the pin insert into the pin hole; the switching of the guide block between the first guide groove and the second guide groove allows the user to choose whether to perform chasing-back or fix the position of the backrest, making the function of the backrest assembly diversified.

[0019] Preferably, the second elastic member is a compression spring; a counterbore is formed in the center of the boss, a through hole is formed at the center of the bottom end of the counterbore, and a retaining ring is fixedly connected above the top end of the counterbore; a convex ring matched with the counterbore is fixedly connected to the plug pin, and the compression spring is arranged between the retaining ring and the convex ring; the retaining ring prevents the plug pin from disengaging from the back bracket by limiting the compression spring and the convex ring, and at the same time enables the plug pin to always receive an elastic force towards the plug pin hole.

[0020] Preferably, a back cover covering the groove is detachably connected to the reverse side of the back bracket, thereby protecting the components inside the back bracket.

[0021] Preferably, the first rod member and the front end of the upper connecting rod are integrally formed; the second rod member and the front end of the lower connecting rod are integrally formed, which improves the strength of the connecting end, reduces the number of components, and facilitates disassembly and installation.

[0022] The beneficial effects of the present utility model adopting the above technical solutions are as follows:

[0023] 1. Compared with the existing push-back chairs on the market, which have problems of complex mechanical structures and inconvenient use, the backrest assembly utilizes the cooperation of the link assembly and the elastic member to achieve the back-tracing function, and at the same time maintains the angle of the backrest through the four-bar linkage mechanism. While providing elastic support for the user's back during back-tracing, the mechanical structure is simple and the use is convenient.

[0024] 2. The backrest assembly and the backrest are detachably connected, and the convenient disassembly and assembly are realized through the structure of the installation groove and the buckle. After disassembly, the occupied space of the backrest assembly is smaller than that of the products on the market, and it is more convenient for transportation.

[0025] 3. Through the cooperation of the plug pin plate installed on the slider and the plug pin, the automatic back-tracing and position fixing of the seat backrest can be realized, and the functions are more diversified, which can meet different usage requirements of users.

[0026] 4. Through the cooperation of the guide block on the knob and the guide groove on the back bracket, under the action of the elastic member, the user only needs to rotate the knob to switch the back-tracing function and the fixed backrest function of the backrest assembly, and the operation is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the general assembly drawing after the backrest assembly is assembled on the seat;

[0028] Figure 2 is the left view of the backrest assembly;

[0029] Figure 3 is the structural schematic diagram of the back of the backrest assembly;

[0030] Figure 4 is the structural schematic diagram of the interior of the back of the backrest assembly;

[0031] Figure 5 Schematic diagram of the position of the groove on the back support

[0032] Figure 6 Exploded view of the components of the knob and pin parts

[0033] Figure 7 Schematic diagram of the structure of the knob

[0034] Figure 8 Schematic diagram of the structure of the counterbore and through hole

[0035] Figure 9 Schematic diagram of the structure of the boss and retaining ring

[0036] Figure 10 Exploded view of the components of the connecting rod assembly and the four-bar linkage

[0037] Figure 11 Schematic diagram of the reset mode of the backrest assembly

[0038] Figure 12 Exploded view of the components on the backrest

[0039] Figure 13 Schematic diagram of the structure after the connection seat and the mounting seat are assembled

[0040] Figure 14 Cross-sectional view of the backrest

[0041] Each reference numeral is: 1 - back support, 2 - tension spring, 3 - upper connecting rod, 31 - first rod, 311 - upper hinge point, 312 - lower hinge point, 4 - lower connecting rod, 41 - second rod, 411 - front hinge point, 412 - rear hinge point, 5 - slider, 6 - counterbore, 7 - backrest, 8 - through hole, 71 - backrest body, 72 - mounting seat, 73 - connection seat, 731 - buckle, 732 - baffle, 8 - through hole, 9 - third rod, 10 - first guide groove, 11 - chute, 1a - groove, 12 - pin plate, 13 - pin hole, 14 - pin, 15 - knob, 16 - back cover, 17 - compression spring, 18 - retaining ring, 19 - convex ring, 20 - boss, 21 - guide block, 22 - second guide groove, 61 - positioning projection. Detailed implementation manners

[0042] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0043] In the following description, many specific details are set forth to provide a thorough understanding of the present utility model. However, the present utility model may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present utility model is not limited by the specific embodiments disclosed below.

[0044] The description of the present utility model based on orientation, such as "the front side of the upper link 3", etc., is described when the upper link 3 is installed on the backrest assembly in the normal use state, that is, the side close to the user is the front side.

[0045] Most chasing-back chairs on the market have relatively complex chasing-back components and are inconvenient to use. They need to rely on the up-and-down movement of the seat surface to drive the backrest to perform chasing-back, and have poor adaptability to people of different heights.

[0046] Such as Figures 1-14 shown, the present utility model provides a novel backrest assembly, specifically as Figures 1-3 shown, including a back support assembly for supporting the user's back. The back support assembly includes a back bracket 1 and a backrest 7; as Figure 10 shown, a chasing-back mechanism is provided on the back support 1. The chasing-back mechanism includes a link assembly and a first elastic member; the link assembly includes an upper link 3 and a lower link 4. One of the rear ends of the upper link 3 and the lower link 4 is slidably connected to the back bracket 1 and the other is rotatably connected to the back bracket 1; the first elastic member acts on the upper link 3 or the lower link 4 that is slidably connected to the back bracket 1; the link-slider mechanism formed by the upper link 3, the lower link 4 and the back bracket 1 can realize the chasing-back function and will not affect the seat surface height, with a simple structure and convenient use.

[0047] In order to maintain the support angle of the backrest 7 for the back unchanged, a backrest translation mechanism is connected between the front ends of the upper link 3 and the lower link 4 and the backrest; the backrest translation mechanism includes a first rod 31 connected to the front end of the upper link 3 and a second rod 41 connected to the front end of the lower link 4. There are an upper hinge point 311 and a lower hinge point 312 spaced up and down on the first rod 31, and a front hinge point 411 and a rear hinge point 412 spaced front and rear on the second rod 41. The lower hinge point 312 of the first rod 31 is hinged to the rear hinge point 412 of the second rod 41. The upper hinge point 311 of the first rod 31 is hinged to a third rod 9; the front end of the third rod 9 and the front hinge point 411 of the second rod 41 are both hinged to the backrest 7; the first rod 31, the second rod 41, the third rod 9 and the backrest form a four-bar mechanism.

[0048] The backrest assembly is divided into a chasing-back mode and a reset mode; as Figure 2 shown, in the chasing-back mode, the first elastic member acts on the corresponding link in the link assembly, and the corresponding link slides on the back bracket 1, prompting the upper link 3 and the lower link 4 to extend forward, so that the backrest 7 is in a forward position, thereby providing elastic chasing-back support for the user's back.Figure 11 As shown in the figure, in the reset mode, when the user applies a backward force to the backrest 7, under the action of the backward external force, the upper link 3 and the lower link 4 are retracted backward, and the corresponding links in the link assembly slide on the backrest support 1, so that the backrest 7 approaches the backrest support 1, and the seat space becomes larger to meet the usage requirements of different users; in this embodiment, the first rod 31 is fixedly connected to the front end of the upper link 3, the second rod 41 is fixedly connected to the lower link 4, and the third rod 9 can rotate around the upper hinge point 311; during the forward and backward movement of the backrest 7, the first rod 31 supports the backrest 7, and the third rod 9 restricts the up and down deflection of the backrest 7 to ensure that the angle of the backrest 7 supporting the back remains unchanged.

[0049] Furthermore, since the backrest 7 is large in volume and occupies a large space during transportation, it is not convenient for transportation. To facilitate transportation, as Figure 10 and Figure 12 shown, the backrest 7 includes a backrest body 71 and a mounting seat 72. The front end of the third rod 9 and the front hinge point 411 of the second rod 41 are both hinged to the mounting seat 72; the connection between the backrest body 71 and the mounting seat 72 is detachable. After disassembly, the volume of the backrest assembly is greatly reduced, which is convenient for its transportation.

[0050] Furthermore, as Figures 12-14 shown, a connection seat 73 for cooperating with the mounting seat 72 is connected to the back side of the backrest body 71. The backrest body 71 is connected to the mounting seat 72 through the connection seat 73, which can avoid the problem of difficult disassembly and assembly caused by directly mounting the backrest body 71 on the backrest translation mechanism, and is convenient for users to disassemble and install;

[0051] Furthermore, to facilitate the disassembly of the backrest 7, an installation groove for cooperating with the mounting seat 72 is provided on the back side of the connection seat 73. A buckle 731 is provided at the lower end of the installation groove, and a baffle 732 is provided at the upper end of the installation groove; when the connection seat 73 slides to the lower end of the mounting seat 72 through the installation groove, the buckle 731 catches the lower end of the mounting seat 72, and the baffle 732 at the upper end of the installation groove closely adheres to the upper end of the mounting seat 72. The buckle 731 and the baffle 732 limit the connection seat 73 in the up and down directions and cooperate with the installation groove to fix the connection seat 73 together; when disassembling, the buckle 731 is toggled to release the fixation between the connection seat 73 and the mounting seat 72, and the connection seat 73 slides out of the mounting seat 72 along the installation groove. The buckle 731 makes the disassembly and assembly without professional tools, further simplifies the disassembly and assembly steps, enables users to disassemble and assemble the backrest by themselves, and improves the user experience.

[0052] Furthermore, as Figure 10As shown, a chute 11 is formed on the backrest support 1; a slider 5 is fitted in the chute 11, and one of the rear ends of the upper connecting rod 3 and the rear end of the lower connecting rod 4 is hinged to the slider 5 so that its rear end can slide along the chute 11, thereby realizing the sliding connection between one of the rear ends of the upper connecting rod 3 and the rear end of the lower connecting rod 4 and the backrest support 1; the chute 11 formed inside the backrest support 1 reduces the volume of the backrest assembly, making the backrest structure more compact and meeting the user's usage requirements in a narrow space.

[0053] Furthermore, as Figure 4 and Figure 5 shown, the first elastic member is a tension spring 2; a groove 1a is formed on the back surface of the backrest support 1, and the groove 1a communicates with the chute 11, and the tension spring 2 is installed in the chute 11; the rear end of the upper connecting rod 3 is hinged to the upper end of the backrest support 1, and the rear end of the lower connecting rod 4 is hinged to the slider 5; the upper end of the tension spring 2 is connected to the upper end of the backrest support 1, and the lower end of the tension spring 2 is connected to the slider 5; in the chasing-back mode, the tension spring 2 pulls the slider 5 to make the connecting rod assembly extend forward; in the reset mode, a backward force acts on the backrest 7 to stretch the tension spring 2, causing the slider 5 and the rear end of the lower connecting rod 4 to move downward, prompting the connecting rod assembly to retract backward; the tension spring 2 enables the chasing-back mechanism to automatically move forward without external force, realizing the elastic support for the user's back and being able to adjust the front and back positions of the backrest 7 according to the user's sitting posture.

[0054] Furthermore, due to the user's need to fix the backrest 7 at different positions, as Figure 4 shown, a pin plate 12 is connected to the slider 5, and a plurality of pin holes 13 arranged vertically are provided on the pin plate 12; a pin 14 is connected to the backrest support 1, and a knob 15 is fixed on the pin 14.

[0055] The position of the slider 5 moving up and down is adjusted by controlling the pin 14 to insert into the pin holes 13 at different positions through the knob 15, thereby adjusting and fixing the position of the backrest 7; the pin 14 is pulled out of the pin hole 13, so that the connecting rod assembly can move freely, and the backrest 7 is prompted to move forward for chasing-back under the action of the tension spring 2; the pin 14 is inserted into the pin holes 13 at different positions, enabling the seat to fix the backrest 7 at different positions according to the user's needs and meeting the different usage requirements of the user.

[0056] Furthermore, in order to facilitate the user to control the pin and thus switch different usage states of the backrest assembly, as Figures 6-9As shown, a second elastic member is connected between the back bracket 1 and the plug pin 14 or the knob 15; a boss 20 is fixedly connected to the reverse side of the back bracket 1, and a through hole 8 matching the plug pin 14 is formed in the center of the boss 20; adjacent first guide grooves 10 and second guide grooves 22 are arranged at opposite positions on the side of the boss 20, the first guide groove 10 is shallower than the second guide groove 22, the first guide groove 10 and the second guide groove 22 are communicated through a slope, and a positioning projection 61 is arranged on the slope; the first guide groove 10, the second guide groove 22 are matched with guide blocks 21 arranged at opposite positions inside the knob 15, and the positioning projection 61 is smoothly connected with the slope, so that the guide blocks 21 can be smoothly switched between the first guide groove 10 and the second guide groove 22.

[0057] Rotate the knob 15 to switch the guide block 21 between the first guide groove 10 and the second guide groove 22; when rotating the knob 15 to switch the position of the guide block 21 from the second guide groove 22 to the first guide groove 10, the guide block 21 passes through the positioning projection 61, and the elastic force of the second elastic member presses the guide block into the first guide groove 10, and the knob 15 drives the plug pin 14 to move upward, and the plug pin 14 is pulled out of the plug hole 13; when rotating the knob 15 to switch the position of the guide block 21 from the first guide groove 10 to the second guide groove 22, the guide block 21 passes through the positioning projection 61, the second elastic member deforms and always acts on the plug pin 14 or the knob 15, presses the guide block 21 into the second guide groove 22, and the knob 15 drives the plug pin 14 to move downward, so that the plug pin 14 is inserted into the plug hole 13; the switching of the guide block 21 between the first guide groove 10 and the second guide groove 22 allows the user to choose whether to pursue the back or fix the position of the backrest 7, making the function of the backrest assembly diversified.

[0058] Furthermore, the second elastic member is a compression spring 17; a counterbore 6 is formed in the center of the boss 20, the through hole 8 is formed at the center of the bottom end of the counterbore 6, and a retaining ring 18 is fixedly connected above the top end of the counterbore 6; a convex ring 19 matching the counterbore 6 is fixedly connected to the plug pin 14, and the compression spring 17 is arranged between the retaining ring 18 and the convex ring 19; the retaining ring 18 prevents the plug pin 14 from disengaging from the back bracket 1 by limiting the compression spring 17 and the convex ring 19, and at the same time makes the plug pin 14 always receive an elastic force towards the plug hole 13, thereby promoting the guide block 21 to always receive an elastic restoring force towards the first guide groove 10 or the second guide groove 22, so that the guide block 21 can smoothly slide into the first guide groove 10 or the second guide groove 22 when passing through the positioning projection 61.

[0059] Furthermore, a back cover 16 covering the groove 1a is detachably connected to the reverse side of the back bracket 1, so as to protect the components inside the back bracket 1, and it is also detachable during installation, which is convenient for the installation of the internal components.

[0060] Furthermore, the first rod member 31 and the front end of the upper connecting rod 3 are integrally formed; the second rod member 41 and the front end of the lower connecting rod 4 are integrally formed, which improves the strength of the connecting end, reduces the number of components, and is convenient for disassembly and installation.

[0061] The above has schematically described the present utility model and its implementation manners. This description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present utility model, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the creation of the present utility model, design similar structural modes and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present utility model.

Claims

1. A chair back assembly, characterized in that: include: A back support assembly, comprising a back support (1) and a backrest (7); A back-chasing mechanism comprises a connecting rod assembly and a first elastic member; the connecting rod assembly comprises an upper connecting rod (3) and a lower connecting rod (4); one of the rear ends of the upper connecting rod (3) and the rear end of the lower connecting rod (4) is slidably connected to a back support (1) and the other is rotatably connected to the back support (1); the first elastic member acts on the upper connecting rod (3) or the lower connecting rod (4) slidably connected to the back support (1); a chair back translation mechanism is connected between the front ends of the upper connecting rod (3) and the lower connecting rod (4) and the backrest (7); the chair back translation mechanism comprises a first rod member (31) connected to the front end of the upper connecting rod (3), a second rod member (41) connected to the front end of the lower connecting rod (4), and the first rod member (3 1) has an upper hinge point (311) and a lower hinge point (312) spaced apart from each other, the second rod (41) has a front hinge point (411) and a rear hinge point (412) spaced apart from each other, the lower hinge point (312) of the first rod (31) is hinged to the rear hinge point (412) of the second rod (41), the upper hinge point (311) of the first rod (31) is hinged to the third rod (9); the front end of the third rod (9) and the front hinge point (411) of the second rod (41) are both hinged to the backrest (7); the first rod (31), the second rod (41), the third rod (9) and the backrest (7) form a four-bar linkage; The chair back assembly is divided into a chasing mode and a reset mode; in the chasing mode, the first elastic member acts on the corresponding connecting rod in the connecting rod assembly to make the upper connecting rod (3) and the lower connecting rod (4) extend forward, so that the backrest (7) is in a forward position; in the reset mode, the backrest (7) is retracted backward under the action of a backward external force, and the corresponding connecting rod in the connecting rod assembly is caused to slide on the back support (1), thereby making the backrest (7) move closer to the back support (1); and the backrest (7) is always kept from deflecting forward and backward under the action of the chair back translation mechanism.

2. A chair back assembly according to claim 1, characterized in that: The backrest (7) comprises a backrest body (71) and a mounting seat (72); the front end of the third rod (9) and the front hinge point (411) of the second rod (41) are both hinged to the mounting seat (72); and the backrest body (71) and the mounting seat (72) are detachably connected.

3. A chair back assembly according to claim 2, characterized in that: A connecting seat (73) for cooperating with the mounting seat (72) is connected to the back surface of the backrest body (71), and the backrest body (71) is connected to the mounting seat (72) via the connecting seat (73).

4. A chair back assembly according to claim 3, characterized in that: The connecting seat (73) is provided with a mounting groove matched with the mounting seat (72) on the reverse side, a buckle (731) is provided at the lower end of the mounting groove, and a baffle (732) is provided at the upper end of the mounting groove; when the connecting seat (73) slides to the lower end of the mounting seat (72) through the mounting groove, the buckle (731) clamps the lower end of the mounting seat (72), and the baffle (732) at the upper end of the mounting groove is closely attached to the upper end of the mounting seat (72), thereby fixing the connecting seat (73); when disassembling, the buckle (731) is moved to release the fixing of the connecting seat (73) and the mounting seat (72), and the connecting seat (73) slides out of the mounting seat (72) along the mounting groove.

5. The chair back assembly according to claim 1, characterized in that: A slide groove (11) is formed on the back bracket (1); a slider (5) is provided in the slide groove (11); and one of the rear ends of the upper connecting rod (3) and the rear ends of the lower connecting rod (4) is hingedly connected to the slider (5) so that the rear ends thereof can slide along the slide groove (11), thereby realizing a sliding connection between the rear ends of the upper connecting rod (3) and the rear ends of the lower connecting rod (4) and the back bracket (1).

6. A chair back assembly according to claim 5, characterized in that: The first elastic member is a tension spring (2); a groove (1a) is formed on the back of the back support (1), and the groove (1a) is connected to the slide groove (11), and the tension spring (2) is installed in the groove (1a); the rear end of the upper connecting rod (3) is hinged to the upper end of the back support (1), and the rear end of the lower connecting rod (4) is hinged to the slider (5); the upper end of the tension spring (2) is connected to the upper end of the back support (1), and the lower end of the tension spring (2) is connected to the slider (5); in the chasing mode, the tension spring (2) pulls the slider (5) to extend the connecting rod assembly forward; in the reset mode, the backward force acts on the backrest (7) to stretch the tension spring (2), so that the slider (5) and the rear end of the lower connecting rod (4) move downward, causing the connecting rod assembly to retract backward.

7. A chair back assembly according to claim 5, characterized in that: The slider (5) is connected to a latch plate (12), and a plurality of latch holes (13) are arranged in an up-and-down arrangement on the latch plate (12); the back bracket (1) is connected to a latch (14), and a knob (15) is fixed to the latch (14); The position of the slider (5) moving up and down is adjusted by controlling the latch pin (14) to be inserted into the latch pin holes (13) at different positions by means of a knob (15), thereby adjusting and fixing the position of the backrest (7); the latch pin (14) is pulled out of the latch pin hole (13), thereby allowing the connecting rod assembly to move freely, thereby causing the backrest (7) to move forward to catch up.

8. A chair back assembly according to claim 7, characterized in that: A second elastic member is connected between the back bracket (1) and the latch (14) or the knob (15); a boss (20) is fixedly connected to the back side of the back bracket (1), and a through hole (8) is formed in the center of the boss (20) to cooperate with the latch (14); adjacent first guide grooves (10) and second guide grooves (22) are provided at opposite positions on the side of the boss (20), the first guide groove (10) is shallower than the second guide groove (22), the first guide groove (10) and the second guide groove (22) are connected via a slope, and a positioning protrusion (61) is provided on the slope; the first guide groove (10) and the second guide groove (22) cooperate with a guide block (21) provided at a relative position on the inner side of the knob (15); The knob (15) is rotated to switch the guide block (21) between the first guide groove (10) and the second guide groove (22); when the knob (15) is rotated to switch the guide block (21) from the second guide groove (22) to the first guide groove (10), the guide block (21) passes through the positioning protrusion (61), and the elastic force of the second elastic member presses the guide block (21) into the first guide groove (10), so that the latch (14) is pulled out of the latch hole (13); when the knob (15) is rotated to switch the guide block (21) from the first guide groove (10) to the second guide groove (22), the guide block (21) passes through the positioning protrusion (61), and the second elastic member is deformed and always acts on the latch (14) or the knob (15), so that the guide block (21) is pressed into the second guide groove (22), so that the latch (14) is inserted into the latch hole (13).

9. A chair back assembly according to claim 8, characterized in that: The second elastic member is a compression spring (17); a countersunk hole (6) is opened at the center of the boss (20); a through hole (8) is formed at the center of the bottom end of the countersunk hole (6); a retaining ring (18) is fixedly connected to the top of the countersunk hole (6); a convex ring (19) matching the countersunk hole (6) is fixedly connected to the latch pin (14); and the compression spring (17) is arranged between the retaining ring (18) and the convex ring (19).

10. The chair back assembly according to claim 7, characterized in that: A back cover (16) covering the groove (1a) is detachably connected to the back side of the back support (1).

11. The chair back assembly according to claim 1, characterized in that: The first rod member (31) and the front end of the upper connecting rod (3) are integrally formed; the second rod member (41) and the front end of the lower connecting rod (4) are integrally formed.

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