Chair and back-chasing structure thereof

Abstract

The utility model discloses a chair and a back chasing structure thereof. The back chasing structure comprises a back bracket, a linkage rod, an upper mounting seat, a locking piece and a lower mounting seat, the front portion of the upper mounting seat is connected with the chair back, the rear portion of the upper mounting seat is hinged to the top of the back support, the lower mounting seat is fixedly connected with the chair seat, the rear portion of the lower mounting seat is hinged to the bottom of the back support, the two ends of the linkage rod are hinged to the upper mounting seat and the lower mounting seat respectively, and the locking piece is mounted on the lower mounting seat and can limit rotation of the back support. Through the arrangement, the back bracket, the chair seat, the linkage rod and the chair back form a stable four-connecting-rod structure; the two ends of the linkage rod are directly connected with the chair back and the chair seat, and the bottom of the linkage rod moves around the hinge point of the back support and the chair seat, so that a better and more stable supporting effect can be provided for the chair back, and the supporting effect of the chair back can be better; and moreover, the connecting structure needs fewer components, so that the structure of the product is simpler, and the cost is lower.

Description

Technical Field

[0001] The utility model relates to the field of household items, in particular to a chair and its backrest structure. Background Art

[0002] In the process of continuous progress and development of chair technology, chairs have been more widely used, and can be used in office, automotive, household and other environments. To meet the original intention of personalized comfort, people need chairs to have corresponding adjustment functions so as to achieve the purpose of enjoying a comfortable life.

[0003] The prior art with the publication number of CN220876337U discloses a push-back seat, including: a seat, a backrest support, a backrest and a push-back mechanism. The upper end of the backrest support is configured to be connected to the backrest. At least one connection port is opened at the rear of the seat. The lower end of the backrest support is inserted into the connection port and rotatably connected to the seat. An installation groove is provided in the seat, and a gas spring and a transmission rod are placed in the installation groove. The movable rod of the gas spring acts on the backrest support through the transmission rod. The telescopic range of the movable rod of the gas spring is limited in the installation groove. When the movable rod of the gas spring extends, the backrest support is pulled to rotate through the transmission rod. During the rotation of the backrest support, the connection point between the transmission rod and the backrest support is always within the enveloping range of the backrest support.

[0004] In the prior art, part of the force on the backrest is transmitted to the backrest support and the gas spring through a linkage rod, and the middle position of the transmission rod is rotatably connected to the backrest support, which makes the support of the backrest unstable; and the prior art requires multi-stage transmission, resulting in a complex structure, a large volume of the seat, and difficulties in assembling and positioning parts. Summary of the Utility Model

[0005] In order to solve the problems of poor support stability and complex structure in the prior art, the purpose of the utility model is to provide a chair and its backrest structure, which requires fewer components, is less interfered by the four-bar structure, has more stable support, and has a simpler structure.

[0006] To achieve the above purpose, the utility model adopts the following technical solutions: a backrest structure, including a backrest support, a linkage rod, an upper mounting seat, a locking member and a lower mounting seat; the front part of the upper mounting seat is connected to the backrest, the rear part of the upper mounting seat is hinged to the top of the backrest support, the lower mounting seat is fixedly connected to the seat, the rear part of the lower mounting seat is hinged to the bottom of the backrest support, both ends of the linkage rod are respectively hinged to the upper mounting seat and the lower mounting seat, and the locking member is installed on the lower mounting seat and can limit the rotation of the backrest support.

[0007] Preferably, the bottom of the backrest is hinged to the seat via a first shaft, the top of the backrest is hinged to the backrest via a second shaft, the bottom of the linkage rod is hinged to the seat via a third shaft, and the top of the linkage rod is hinged to the backrest via a fourth shaft; wherein, the third shaft is located on the front side of the first shaft, and the fourth shaft is located on the front side of the second shaft.

[0008] Preferably, the locking member is a gas spring. One end of the gas spring is hinged to the seat via a fifth shaft, and the other end of the gas spring is hinged to the backrest via a sixth shaft; wherein, the sixth shaft is located below the first shaft.

[0009] Preferably, a control assembly for controlling the locking member is provided on the seat.

[0010] Preferably, the control assembly includes a handle, a pull rope, and a driving plate. The handle and the driving plate are both rotatably mounted on the seat. The two ends of the pull rope are respectively connected to the handle and the driving plate. The rear part of the driving plate can extend into the second cavity through the front connection port on the lower mounting seat, and the rear part of the driving plate is in contact with the switch of the locking member; when the handle rotates, it can drive the driving plate to rotate through the pull rope, causing the driving plate to act on the switch of the locking member, unlocking the locking member and driving the backrest to rotate.

[0011] Preferably, a first cavity is provided inside the backrest, and an upper connection port and a lower connection port are provided on the backrest. Both the upper connection port and the lower connection port communicate with the first cavity; a second cavity is provided inside the lower mounting seat, and a front connection port and a rear connection port are provided on the lower mounting seat. Both the front connection port and the rear connection port communicate with the second cavity; the rear part of the lower mounting seat extends into the lower connection port of the backrest, and the first cavity and the second cavity communicate through the rear connection port. The rear part of the upper mounting seat extends into the upper connection port, and both ends of the linkage rod are located in the first cavity and the second cavity respectively, and the locking member is located in the second cavity.

[0012] Preferably, an arc-shaped waist-shaped hole is further provided on the lower mounting seat; one end of the locking member is hinged to the seat via a fifth shaft, and the other end of the locking member is hinged to the backrest via a sixth shaft, and the sixth shaft passes through the waist-shaped hole.

[0013] Preferably, a rotating assembly is installed on the seat, and the seat can rotate on the rotating assembly.

[0014] Preferably, the seat is installed on a lifting cylinder.

[0015] A chair includes the above-mentioned chasing back structure.

[0016] The beneficial effects of the technical solution of the present utility model are as follows: The backrest support, seat, linkage rod, and backrest form a stable four-bar linkage structure; both ends of the linkage rod are directly connected to the backrest and the seat, and the bottom of the linkage rod moves around the hinge point between the backrest support and the seat, so that a better and more stable support effect can be provided for the backrest, and the support effect of the backrest can be better; in the above structure, after the upper mounting seat, lower mounting seat, backrest support, linkage rod, and locking member are installed together, the backrest and the seat are installed, so that the product can be assembled modularly, which is convenient for the assembly, maintenance, and transportation of the product; and the above connection structure requires fewer components, making the structure of the product simpler and the cost lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the chair Figure 1 ;

[0018] Figure 2 is a schematic structural diagram of the chair Figure 2 ;

[0019] Figure 3 is a schematic structural diagram of the chair after removing the backrest and seat cushion;

[0020] Figure 4 is a schematic structural diagram of the chair after removing the backrest, seat cushion, and seat;

[0021] Figure 5 is a schematic structural diagram of the chair after removing the backrest, seat cushion, seat, and backrest support;

[0022] Figure 6 is a schematic connection structure diagram of the linkage rod, locking member, and control component;

[0023] Figure 7 is a schematic structural diagram of the lower mounting seat Figure 1 ;

[0024] Figure 8 is a schematic structural diagram of the lower mounting seat Figure 2 ;

[0025] Figure 9 is a schematic structural diagram of the seat Figure 1 ;

[0026] Figure 10 is a schematic structural diagram of the seat Figure 2 ;

[0027] Figure 11 is a schematic structural diagram of the upper mounting seat;

[0028] Figure 12 is a schematic structural diagram of the connecting plate;

[0029] Figure 13It is a schematic structural diagram of a backrest support.

[0030] Reference numerals: 1, seat; 11, first accommodating portion; 111, first accommodating groove; 112, first through hole; 12, second accommodating portion; 121, second accommodating groove; 122, second through hole; 13, second upright post; 14, third through hole; 15, third accommodating groove; 151, third accommodating groove; 17, fourth accommodating portion; 171, fourth accommodating groove; 18, first upright post; 19, accommodating space; 10, seat cushion;

[0031] 2, backrest support; 21, first cavity; 22, first connection hole; 23, second connection hole; 24, third connection hole; 25, upper connection port; 26, lower connection port; 27, first shaft;

[0032] 3, backrest; 31, mounting bracket;

[0033] 41, linkage rod; 42, third shaft; 43, upper mounting seat; 44, second shaft; 45, fourth shaft; 46, connecting plate;

[0034] 51, handle; 52, pull rope; 53, driving plate; 55, locking member; 56, hinge seat; 58, fifth shaft; 59, sixth shaft;

[0035] 66, rotating seat;

[0036] 7, control rod; 71, pressing portion;

[0037] 8, lower mounting seat; 81, second cavity; 82, fourth connection hole; 83, waist-shaped hole; 84, fifth connection hole; 85, sixth connection hole; 87, front connection port; 88, rear connection port;

[0038] 9, armrest; 91, connecting bracket. Detailed implementation manners

[0039] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0040] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0041] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality" is two or more, unless otherwise clearly defined.

[0042] In the present utility model, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0043] In the present utility model, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "beneath" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature. Embodiment

[0044] As Figures 1 to 13 shown, a chasing-back structure includes a seat 1, a backrest 3, a backrest bracket 2, a linkage rod 41 and a locking member 55;

[0045] The bottom of the backrest support 2 is hinged to the seat 1, the top of the backrest support 2 is hinged to the backrest 3, the bottom of the linkage rod 41 is hinged to the seat 1, the top of the linkage rod 41 is hinged to the backrest 3, and the locking member 55 is installed on the seat 1. The locking member 55 is used to drive the backrest support 2 to rotate on the seat 1.

[0046] With such a setting, the backrest support, the seat, the linkage rod and the backrest form a stable four-bar linkage structure; both ends of the linkage rod are directly connected to the backrest and the seat, and the pressure from the backrest is directly shunted by the seat and the locking member, so that a better and more stable support effect can be provided for the backrest, and the support effect of the backrest can be better; the components required for the above connection structure are also simpler, which is convenient for the production, assembly and transportation of the product.

[0047] In this embodiment, as Figures 1 to 6 shown, the bottom of the backrest support 2 is hinged to the seat 1 through the first shaft 27, the top of the backrest support 2 is hinged to the backrest 3 through the second shaft 44, the bottom of the linkage rod 41 is hinged to the seat 1 through the third shaft 42, and the top of the linkage rod 41 is hinged to the backrest 3 through the fourth shaft 45; wherein, the third shaft 42 is located on the front side of the first shaft 27, and the fourth shaft 45 is located on the front side of the second shaft 44. With such a setting, the structure of the product can be made more compact.

[0048] In this embodiment, as Figure 2 、 Figure 4 and Figure 6 shown, the locking member 55 is a gas spring. One end of the gas spring is hinged to the seat 1 through the fifth shaft 58, and the other end of the gas spring is hinged to the backrest support 2 through the sixth shaft 59. Among them, the sixth shaft 59 is located below the first shaft 27. With such a setting, the components required to control the movement of the backrest support can be reduced by the gas spring, making the structure more compact.

[0049] In this embodiment, as Figure 2 and Figure 5 shown, it further includes an upper mounting seat 43 and a lower mounting seat 8. The backrest 3 is mounted on the upper mounting seat 43. The rear part of the upper mounting seat 43 is hinged to the top of the backrest support 2. The backrest 3 is mounted on the upper mounting seat 43. The front part of the lower mounting seat 8 is fixedly connected to the seat 1, the rear part of the lower mounting seat 8 is hinged to the bottom of the backrest support 2, both ends of the linkage rod 41 are respectively hinged to the upper mounting seat 43 and the lower mounting seat 8, and the locking member 55 is installed on the lower mounting seat 8. With such a setting, after the upper mounting seat, the lower mounting seat, the backrest support, the linkage rod and the locking member are installed together, the backrest and the seat are installed, so that the product can be assembled modularly, which is convenient for the assembly, maintenance and transportation of the product.

[0050] In this embodiment, as Figure 2 、 Figure 4 、 Figure 9 and Figure 13As shown in the figure, a first cavity 21 is provided inside the back bracket 2. An upper connection port 25 and a lower connection port 26 are provided on the back bracket 2. Both the upper connection port 25 and the lower connection port 26 communicate with the first cavity 21. A second cavity 81 is provided inside the lower mounting base 8. A front connection port 87 and a rear connection port 88 are provided on the lower mounting base 8. Both the front connection port 87 and the rear connection port 88 communicate with the second cavity 81. An arc-shaped waist-shaped hole 83 is also provided on the lower mounting base 8, and the waist-shaped hole 83 communicates with the second cavity 81. As Figure 2 shown, the rear part of the lower mounting base 8 extends into the lower connection port 26 of the back bracket 2. The first cavity 21 and the second cavity 81 communicate through the rear connection port 88. The waist-shaped hole 83 is located inside the first cavity 21. The fourth shaft 45 passes through the linkage rod and is connected to the first mounting base. The sixth shaft 59 passes through the waist-shaped hole 83 and is connected to the back bracket 2. The linkage rod 41 is arranged inside the first cavity 21 of the back bracket 2. The bottom of the linkage rod 41 extends into the second cavity 81 through the rear connection port 88. The rear part of the upper mounting base 43 extends into the first cavity 21 from the upper connection port 25. The second shaft 44 is located inside the first cavity 21. The gas spring is arranged inside the second cavity 81. With such a setting, a certain sealed space can be provided for the linkage structure, and it can effectively prevent clothes from being clamped, improving the comfort of using the chair.

[0051] Further preferably, the back bracket 2 includes a first support seat and a first cover plate. The first support seat and the first cover plate are fixedly connected. The first support seat and the first cover plate cooperate to form the first cavity 21, the upper connection port 25 and the lower connection port 26. The lower mounting base 8 includes a second support seat and a second cover plate. The second support seat and the second cover plate are fixedly connected. The second support seat and the second cover plate cooperate to form the second cavity 81, the front connection port 87 and the rear connection port 88.

[0052] In this embodiment, as Figure 13 shown, a first connection hole 22, a second connection hole 23 and a third connection hole 24 are provided on the back bracket 2. As Figure 8 shown, a fourth connection hole 82, a fifth connection hole 84 and a sixth connection hole 85 that communicate with the second cavity 81 are provided on the lower mounting base 8. As Figure 11As shown in the figure, a seventh connection hole 432 and an eighth connection hole 433 are provided on the upper mounting seat 43, and a ninth connection hole and a tenth connection hole are provided on the linkage rod 41; the first shaft 27 passes through the fourth connection hole 82 and the fifth connection hole 84 to hinge the lower mounting seat 8 and the backrest bracket 2, and the second shaft 44 passes through the eighth connection hole 433 and the third connection hole 24 to hinge the upper mounting seat 43 and the backrest bracket 2, and the third shaft 42 passes through the ninth connection hole and the sixth connection hole 85 to connect the linkage rod 41 to the lower mounting seat 8, and the fourth shaft 45 passes through the tenth connection hole and the seventh connection hole 432 to hinge the linkage rod 41 and the upper mounting seat, and the fifth shaft 58 passes through the fourth connection hole 82 to hinge the gas spring and the lower mounting seat 8, and both ends of the sixth shaft 59 pass through the gas spring and the waist-shaped hole 83 and then are hinged to the second connection hole 23 of the backrest bracket to hinge the gas spring and the backrest bracket 2. Such a setting facilitates the batch production of parts and is conducive to the assembly, maintenance and replacement of parts of the product.

[0053] In this embodiment, as Figures 2 to 6 shown, a control assembly for controlling the locking member 55 is provided on the seat 1; the control assembly includes a handle 51, a pull rope 52 and a drive plate 53. The handle 51 and the drive plate 53 are both rotatably mounted on the seat 1. The two ends of the pull rope 52 are respectively connected to the handle 51 and the drive plate 53. The rear part of the drive plate 53 can extend into the second cavity 81 through the front connection port 87 on the lower mounting seat 8, and the rear part of the drive plate 53 is connected to the switch of the locking member 55; when the handle 51 rotates, it can drive the drive plate 53 to rotate through the pull rope 52, so that the drive plate 53 acts on the switch of the locking member 55, unlocking the locking member 55 and driving the backrest bracket 2 to rotate. The switch of the locking member 55 is the contact of the gas spring.

[0054] In this embodiment, as Figure 1 、 Figure 2 、 Figure 3 、 Figure 9 and Figure 10 shown, a downwardly concave accommodating space 19 is provided at the top of the seat 1; a first accommodating portion 11 protrudes in the accommodating space 19, a first accommodating groove 111 is provided at the bottom of the seat 1, the first accommodating groove 111 is located in the first accommodating portion 11, and a first through hole 112 communicating with the first accommodating groove 111 is provided on the first accommodating portion 11; the handle 51 is installed on the hinge seat, the hinge seat 56 is fixed in the first accommodating groove 111, and the pull rope 52 extends into the seat 1 through the first through hole 112; a second accommodating portion 12 protrudes in the accommodating space 19, a second accommodating groove 121 is provided at the bottom of the seat 1, the second accommodating groove 121 is located in the second accommodating portion 12, and a second through hole 122 communicating with the second accommodating groove 121 is provided on the second accommodating portion 12; after the lower mounting seat 8 is inserted into the second accommodating groove 121, it is fixedly connected by bolts, and the rear part of the drive plate 53 extends into the second accommodating groove 121 through the second through hole 122. Such a setting facilitates the positioning and installation of parts.

[0055] In this embodiment, as shown in Figure 2 , Figure 3 , Figure 4 and Figure 9 , two first columns 18 protrude in the accommodation space 19, and hinge portions 531 protrude on the driving plate 53. The two hinge portions 531 are respectively connected to the two first columns 18. A first pressing plate is fixed on the first column 18, and the first pressing plate restricts the driving plate 53 on the first column 18.

[0056] In this embodiment, as shown in Figure 2 , Figure 3 , Figure 4 and Figure 11 , the chair back 3 is installed on the mounting frame 31, and the mounting frame 31 is installed on the upper mounting seat 43 through the connecting plate 46. Specifically, a first connecting portion 431 protrudes from the rear of the upper mounting seat 43, and both the seventh connecting hole 432 and the eighth connecting hole 433 are provided on the first connecting portion 431. The second shaft 44 and the fourth shaft 45 are both installed on the first connecting portion 431; a second connecting portion 434 protrudes from the front of the upper mounting seat 43, a limiting portion 435 protrudes around the second connecting portion 434, and a hook 436 protrudes from the front of the second connecting portion 434; as shown in Figure 12 , a positioning groove 461 is provided at the rear of the connecting plate 46, a limiting groove 462 is provided on the side wall of the positioning groove 461, a clamping groove 463 is opened on the front side wall of the positioning groove 461, and a clamping protrusion 464 protrudes in the clamping groove 463. The second connecting portion 434 of the upper mounting seat 43 is inserted into the positioning groove 461, the limiting portion 435 is inserted into the limiting groove 462, and the hook 436 extends into the clamping groove 463 and hooks the clamping protrusion 464. With such a setting, it is a modular setting with a quick connection and positioning structure, which is convenient for the disassembly and assembly of parts.

[0057] In this embodiment, as shown in Figure 9 and Figure 10 , a third accommodation portion 15 protrudes at the middle position of the accommodation space 19, and a third accommodation groove 151 for installing on the rotating assembly is provided at the middle position of the bottom of the seat 1. The third accommodation groove 151 is located inside the third accommodation portion 15, and the third accommodation groove 151 is located within the third accommodation portion 15. The rotating assembly is installed in the third accommodation groove. The fixed seat of the rotating assembly is fixedly connected to the seat, and the rotating seat of the rotating assembly is rotatably matched with the fixed seat. The seat can rotate on the rotating assembly. With such a setting, the overall structure of the product is more compact.

[0058] Furthermore, a plurality of positioning grooves 461 are provided on the top wall of the third accommodation groove 151, and a plurality of positioning posts 67 protrude on the fixed seat 65. The positioning posts 67 are inserted into the positioning grooves 461.

[0059] In this embodiment, the seat 1 is installed on the telescopic end of the lifting cylinder. A swingable control rod 7 is installed on the seat 1, and the control rod 7 is used to control the movement of the lifting cylinder. Specifically, the telescopic end of the lifting cylinder protrudes from the rotating seat 66 and extends into the accommodating space 19. The lifting cylinder is fixedly connected to the rotating seat 66. Two oppositely arranged second upright columns 13 protrude from the seat 1. The bottoms of the two second upright columns 13 are fixedly connected by a second pressing plate. A third through hole 14 is formed in the seat 1. A pressing portion 71 protruding downward is provided at the front of the control rod 7. The control rod 7 extends out between the two second upright columns 13. The rear part of the control rod 7 is arranged above the contact head of the lifting cylinder. The pressing portion 71 at the front of the control rod 7 protrudes from the bottom of the seat 1 through the third through hole.

[0060] A chair includes the above-mentioned backrest structure. A seat cushion 10 is fixed on the top of the seat 1, and the seat cushion covers the accommodating space 19. A fourth accommodating portion 17 protrudes in the accommodating space of the seat. A fourth accommodating groove 171 is provided at the bottom of the seat 1. The fourth accommodating groove is located in the fourth accommodating portion. The connecting bracket 91 is inserted into the fourth accommodating groove, and the connecting bracket 91 is fixedly connected to the seat. One end of the connecting bracket extends out of the seat, and the armrest 9 is installed on the connecting bracket.

[0061] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0062] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principle and purpose of the present invention.

Claims

1. A chasing back structure, characterized in that: It includes a backrest support (2), a linkage rod (41), an upper mounting base (43), a locking member (55) and a lower mounting base (8); The front part of the upper mounting base (43) is connected to the backrest (3), the rear part of the upper mounting base (43) is hinged to the top of the backrest support (2), the lower mounting base (8) is fixedly connected to the seat (1), the rear part of the lower mounting base (8) is hinged to the bottom of the backrest support (2), both ends of the linkage rod (41) are respectively hinged to the upper mounting base (43) and the lower mounting base (8), the locking member (55) is mounted on the lower mounting base (8), and the locking member (55) can limit the rotation of the backrest support.

2. The chasing-back structure according to claim 1, wherein: The bottom of the backrest support (2) is hinged to the seat (1) through a first shaft (27), the top of the backrest support (2) is hinged to the backrest (3) through a second shaft (44), the bottom of the linkage rod (41) is hinged to the seat (1) through a third shaft (42), and the top of the linkage rod (41) is hinged to the backrest (3) through a fourth shaft (45); wherein, the third shaft (42) is located on the front side of the first shaft (27), and the fourth shaft (45) is located on the front side of the second shaft (44).

3. The chasing back structure according to claim 2, characterized in that: The locking member (55) is a gas spring, one end of the gas spring is hinged to the seat (1) through a fifth shaft (58), and the other end of the gas spring is hinged to the backrest support (2) through a sixth shaft (59); wherein, the sixth shaft (59) is located below the first shaft (27).

4. The pursuit back structure according to claim 3, characterized in that: A control component for controlling the locking member (55) is provided on the seat (1).

5. The chasing-back structure according to claim 4, characterized in that: The control component includes a handle (51), a pull rope (52) and a driving plate (53). The handle (51) and the driving plate (53) are both rotatably mounted on the seat (1). Both ends of the pull rope (52) are respectively connected to the handle (51) and the driving plate (53). The rear part of the driving plate (53) can extend into the second cavity (81) through the front connection port (87) on the lower mounting base (8), and the rear part of the driving plate (53) is connected to the switch of the locking member (55); when the handle (51) rotates, it can drive the driving plate (53) to rotate through the pull rope (52), so that the driving plate (53) acts on the switch of the locking member (55), unlocking the locking member (55) and driving the backrest support (2) to rotate.

6. The chasing-back structure according to claim 1, wherein: A first cavity (21) is provided inside the backrest support (2), and an upper connection port (25) and a lower connection port (26) are provided on the backrest support (2). Both the upper connection port (25) and the lower connection port (26) are communicated with the first cavity (21); A second cavity (81) is provided inside the lower mounting base (8), and a front connection port (87) and a rear connection port (88) are provided on the lower mounting base (8). Both the front connection port (87) and the rear connection port (88) are communicated with the second cavity (81); The rear part of the lower mounting base (8) extends into the lower connection port (26) of the backrest support (2), the first cavity (21) and the second cavity (81) are communicated through the rear connection port (88), the rear part of the upper mounting base (43) extends into the upper connection port (25), both ends of the linkage rod (41) are respectively located in the first cavity (21) and the second cavity (81), and the locking member (55) is located in the second cavity (81).

7. A chasing back structure according to claim 6, characterized in that: An arc-shaped kidney-shaped hole (83) is further provided on the lower mounting base (8); one end of the locking member (55) is hinged to the seat (1) through a fifth shaft (58), and the other end of the locking member (55) is hinged to the backrest support (2) through a sixth shaft (59), and the sixth shaft (59) passes through the kidney-shaped hole (83).

8. A chasing-back structure according to claim 1, characterized in that: The seat (1) is equipped with a rotating assembly, and the seat can rotate on the rotating assembly.

9. The chasing-back structure according to claim 1, characterized in that: The seat (1) is mounted on a lifting cylinder.

10. A chair, characterized in that: It includes a chasing-back structure according to any one of the above claims 1-9.

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