Novel chair back and chair

Abstract

The invention provides a novel chair back and a chair, the novel chair back comprises a back support member and rib side support assemblies symmetrically arranged on the left and right sides of the back support member, and a tooth portion linkage mechanism is arranged between frameworks of the two rib side support assemblies, so that a user can manually pull one rib side support member to trigger the tooth portion linkage mechanism, and the tooth portion linkage mechanism can trigger the other rib side support member. Therefore, the two rib side supporting pieces stay at the corresponding positions after being far away from each other or close to each other, effective supporting is formed for the ribs of a user, the adjusting mode is simple, operation is convenient, and the sitting posture adjusting device can be suitable for children or adults of different postures to sit; the rib clamping chair back is arranged on the chair, and the supporting force of the rib side supporting piece is not influenced by the gravity of a seated person, so that when users with different body forms sit on the chair, the users can adjust the supporting force of the rib side supporting piece on the rib side according to own requirements, and the use experience feeling of the chair is improved.

Description

Technical Field

[0001] This invention relates to the field of chairs, and particularly to a novel chair back and chair. Background Technology

[0002] The chairs currently available on the market include chairs for adults, such as office chairs, as well as chairs for children, such as study chairs. Many of these chairs have side supports to correct the user's posture and prevent health problems such as scoliosis.

[0003] For example, in the chair patent with publication number CN219613431, the chair back is equipped with horizontally adjustable clamping arms. The ends of the two clamping arms open to form clamping parts for clamping the area below the armpits and the ribs. The clamping arms include a fixing part with two horizontally spaced fixing holes. The backrest is equipped with corresponding adjustment holes, so that the clamping arms can be engaged with different fixing holes and adjustment holes by screws to adjust the distance between the two clamping arms, making the chair suitable for adults of different body types or children at different developmental stages. However, adjusting the distance between the clamping arms requires repeated disassembly and reassembly of screws, making the adjustment process rather cumbersome.

[0004] For example, in the chair patent with publication number CN102726973, two supports are set on both sides of the seat. A drive unit and a linkage mechanism are connected between the two supports. When the user sits on the seat, the drive unit and linkage mechanism are triggered, and the two supports clamp the waist from both sides of the seat. This chair can convert the gravitational potential energy generated by the human body sitting on the seat into the kinetic energy of the two supports clamping the waist. In this way, the waist of adults or children of different body shapes can be supported on both sides when sitting. However, since the support force clamping the waist is mainly affected by the weight of the person sitting, the support force on the waist is directly proportional to the weight of the person sitting. That is to say, the greater the weight of the person sitting, the greater the support force on the waist. This makes it difficult for people of different body shapes to adjust the support force on the waist according to their own needs after sitting, which affects the sitting experience of the chair. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a novel chair back. By setting a toothed linkage mechanism between the frames of two rib-side support components, the user can manually pull one of the rib-side support components to trigger the toothed linkage mechanism, thereby causing the two rib-side support components to move away from or closer to each other and remain in the corresponding positions, effectively supporting the user's ribs. The adjustment method is simple and easy to operate, and it is suitable for children or adults of different body shapes to sit on.

[0006] Furthermore, a chair is provided in which the novel backrest is installed on the chair, and the supporting force of the rib side support is not affected by the weight of the sitter. This allows users of different body types to adjust the supporting force of the rib side support according to their own needs, thereby improving the user experience of the chair.

[0007] The technical solution of this invention is implemented as follows: A new type of chair back, including Back support; used to provide support for the back; The rib-side support assembly is symmetrically arranged on the left and right sides of the back support member. The rib-side support assembly includes rib-side support members and skeletons that are connected to each other. The portion of the rib-side support member that extends forward beyond the front end of the back support member has a support surface. The two support surfaces are opposite each other and a support area is formed between the two support surfaces. A toothed linkage structure is provided between the two skeletons. The toothed linkage structure includes a rack on the skeleton located inside the rib-side support member. The two racks are staggered and the teeth of the two racks are simultaneously engaged with a linkage gear. An external force acts on one of the rib-side supports and triggers the toothed linkage structure, causing the two rib-side supports to move closer or further apart to adjust the size of the support area; and the two rib-side supports, after adjustment, can stay in the corresponding position and remain in place.

[0008] Preferably, at least one end of the linkage gear is connected to a rotating shaft, and the back support is provided with a rotating shaft hole corresponding to the position of the rotating shaft, and the rotating shaft is rotatably connected in the rotating shaft hole; after the rotating shaft connecting the end of the linkage gear is engaged with the rotating shaft hole, it can provide rotational support for the linkage gear, so that the linkage gear can be stably rotatably connected to the back support.

[0009] Preferably, the support area has a maximum support space and a minimum support space; the two side support members move closer to each other to the minimum width or further apart to the maximum width, allowing the support area to switch between the minimum and maximum support spaces; thus making the chair back suitable for the needs of users of different body types. Preferably, the frame includes a body and a rack connected to the inner end of the body. The width of the body is greater than the width of the rack, and a stepped surface is formed at the connection between the body and the rack. The stepped surface on one frame is opposite to the end of the rack on the other frame. When the two rib-side supports approach each other to their minimum width, the stepped surface on one frame abuts against the end of the rack on the other frame. This ensures that the two frames slide within a reasonable range when sliding left and right, avoiding misalignment of the racks on the two frames during sliding, which would cause interference between the two rib-side support components.

[0010] Preferably, it also includes a connector connected to each frame, and the back support is provided with a sliding groove extending to the left and right, and the connector is slidably connected in the sliding groove; the connector is equivalent to the mounting carrier of the rib side support assembly, and by sliding the connector in the sliding groove, the rib side support assembly can move in the left and right direction.

[0011] Preferably, the slide includes limiting ends on its left and right sides. When the two rib-side supports move away from each other to their maximum width, the limiting ends abut against the connecting member, so that the two rib-side supports will not come out of the back support when they are at their maximum width.

[0012] Preferably, the connector is a U-shaped plate with a U-shaped groove, and the frame has a corresponding insert plate. The insert plate is inserted into the U-shaped groove and connected to the U-shaped plate by screws. The U-shaped groove can provide insertion guidance for the insert plate, and the screw connection after the insert plate is inserted into the U-shaped groove also makes the connection between the insert plate and the connector more stable.

[0013] Preferably, at least one of the left-side rib support assembly and the right-side rib support assembly is provided with a control adjustment mechanism between itself and the back support member. The control adjustment mechanism is configured to lock and unlock the position of the corresponding rib support assembly that moves left and right, so that the corresponding rib support assembly can slide left and right and adjust, and the adjusted rib support assembly can stay in the corresponding position.

[0014] Preferably, the control and adjustment mechanism includes a control rod connected to the rib-side support assembly. The back support member is provided with multiple position holes spaced apart in the left-right direction for cooperating with the control rod. When the control rod disengages from the corresponding position hole, the corresponding rib-side support member can move left and right and adjust the size of the support area. When the control rod is inserted into the corresponding position hole, the corresponding rib-side support member can stay in the adjusted position. This simplifies the locking and unlocking process of the rib-side support assembly to a simple pulling process of the control rod, making the position adjustment and locking of the rib-side support assembly simple and efficient.

[0015] Preferably, each frame is connected to a corresponding U-shaped plate; a U-shaped groove is formed on the U-shaped plate, which is surrounded by two spaced flat plates and a vertical plate connected between the two flat plates. The opposite end of the vertical plate has an outward opening, and the frame has a corresponding insert plate. The insert plate is inserted into the U-shaped groove through the opening and connected to the U-shaped plate by screws. The insert plate is spaced from the vertical plate, thus forming a guide groove that communicates with the outside. The control rod is inserted into the guide groove. The control rod uses the space between the insert plate and the vertical plate, so that the control rod can slide left and right with the corresponding rib side support component, while locking and unlocking the position of the corresponding rib side support component. The design is simple and the structure is ingenious.

[0016] Preferably, the control lever has a side extension extending inward from the back support near the back support member, and the side extension is positioned opposite to the rib support member. When the control lever disengages from the corresponding gear position socket, the side extension abuts against the rib support member, forming a hook-and-limit mechanism between the control lever and the rib support member to prevent the control lever from detaching from the rib support assembly when disengaging from the gear position socket.

[0017] Preferably, the back support is connected to a back plate at the front end. The back plate covers the front surface of the back support and has clearance grooves to allow the frame to move left and right. The back plate can hide the frame while concealing the front surface of the back support, and the clearance grooves can provide clearance space for the frame to slide left and right. The design is ingenious and achieves two goals at once.

[0018] Preferably, each frame is connected to a corresponding connector, and the back support is provided with a sliding groove extending to the left and right, in which the connector is slidably connected; when the back plate is connected to the front end of the back support, the rear end of the back plate abuts against the front end of the connector; the back plate can also limit the connector to prevent it from coming out of the sliding groove.

[0019] Preferably, the support surface of the rib support is connected to a soft pad; the soft pad can provide a soft support feel to the ribs and improve the sitting experience.

[0020] Preferably, the width variation range between the two rib side supports is 240mm-380mm.

[0021] A chair, including the novel chair back described above.

[0022] The beneficial effects of the present invention, which adopts the above technical solution, are as follows: 1. The novel chair back of the present invention can link the rib support components on both sides of the chair back through the toothed linkage structure. The structure is simple and easy to operate. When the user adjusts the size of the support area to suit his body shape, he only needs to pull one of the rib support components. There is no need to repeatedly disassemble and assemble screws, which simplifies the adjustment process of the support space.

[0023] 2. The two side support components in the new chair back change the size of the support space through the toothed linkage structure and can stay in the corresponding position. Therefore, the support force of the two side support components on the side is not affected by the weight of sitting. The sitter can adjust the support force of the side support components according to their own choice and needs, thus improving the sitting experience of the chair.

[0024] 3. In the control and adjustment mechanism, the control lever and multiple position sockets can simplify the process of locking and unlocking the position of the rib side support component to the pulling process of the control lever. The structure is simple, easy to operate, and has a high adjustment effect.

[0025] 4. The front surface of the back support component is connected to the back panel to form a double-layer structure. This not only conceals the frame inside the double-layer structure to optimize the appearance of the chair back, but also provides clearance grooves on the back panel to prevent the frame from sliding, ensuring normal sliding adjustment of the rib support components. This ingenious design achieves two goals at once. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the new type of chair back; Figure 2 This is an enlarged view of the control lever. Figure 3 An exploded view of the new type of chair back; Figure 4 An exploded view of the new chair back from another angle; Figure 5 This is a schematic diagram showing the two rib-side supports moving away from each other. Figure 6 This is a schematic diagram showing the two rib-side supports brought closer together. Figure 7 A sectional view showing the control rod connection position; The attached figures are labeled as follows: 1-back support, 2-rib side support, 3-linkage gear, 4-control lever, 5-back plate, 11-slide groove, 12-rotating shaft hole, 13-gear insertion hole, 22-soft pad, 23-frame, 24-rack, 25-U-shaped plate, 31-rotating shaft, 51-avoidance groove, 111-limiting end, 231-insertion plate, 232-step surface, 251-U-shaped groove, 252-guide groove, 253-vertical plate, 254-flat plate. Detailed Implementation

[0027] To better understand the above-mentioned objectives, 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 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 invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0029] The specific implementation methods of this invention are as follows: like Figure 1-7 As shown, this embodiment provides a novel chair back, comprising: Back support 1; used to provide support for the back, back support 1 is usually a plate-like structure; The rib-side support assembly is symmetrically arranged on the left and right sides of the back support 1. The rib-side support assembly includes rib-side support members 2 and skeletons 23 connected to each other. The rib-side support member 2 is a plate-like structure. The front end of the plate-like structure protrudes forward and forms a parabolic arc to imitate the curve of the human spine. The part of the rib-side support member 2 that extends forward beyond the front end of the back support 1 has a support surface. The two support surfaces are opposite each other and a support area is formed between the two support surfaces. A toothed linkage structure is provided between the two skeletons 23. The toothed linkage structure includes a rack 24 on the skeleton 23 located inside the rib-side support member 2. The two racks 24 are staggered from left to right, and the teeth of the two racks 24 are simultaneously engaged with a linkage gear 3. When adjusting the size of the support area, an external force is applied to one of the rib-side support members 2 and triggers the toothed linkage structure, causing the two rib-side support members 2 to move closer or further apart to adjust the size of the support area. The external force usually refers to the pulling force of manpower to pull one of the rib-side support members 2; and the two rib-side support members 2 after adjustment can stay in the corresponding position and remain in place.

[0030] Furthermore, in order to enable the linkage gear 3 to rotate stably, at least one end of the linkage gear 3 is connected to a rotating shaft 31. The back support 1 is provided with a rotating shaft hole 12 corresponding to the position of the rotating shaft 31. In this embodiment, both ends of the linkage gear 31 are provided with rotating shafts 31, and the rotating shafts 31 are rotatably connected in the rotating shaft hole 12. After the rotating shaft 31 connecting the end of the linkage gear 3 is engaged with the rotating shaft hole 12, it can provide rotational support for the linkage gear 3, so that the linkage gear 3 can be stably rotatably connected to the back support 1.

[0031] Furthermore, the support space of the support area formed by the two side support members 2 during adjustment has a maximum support space and a minimum support space; the two side support members 2 move closer to each other to the minimum width or further away from each other to the maximum width, allowing the support area to switch between the minimum and maximum support spaces; this makes the chair back suitable for the needs of diners of different body types; when the two side support members 2 move closer to each other and the support area is at the minimum support space, the two side support members 2 cannot continue to move closer to each other to avoid interference between the two side support members 2. Specifically, the frame 23 includes a body and a connection to the inner end of the body. The width of the rack 24 body is greater than the width of the rack 24, and a stepped surface 232 is formed at the position where the body and the rack 24 are connected. The stepped surface 232 on one frame 23 is opposite to the end of the rack 24 on the other frame 23. When the two rib-side support members 2 approach each other to the minimum width, the stepped surface 232 on one frame 23 abuts against the end of the rack 24 on the other frame 23. This ensures that the two frames 23 slide left and right within a reasonable range, and avoids the racks 24 on the two frames 23 from being misaligned during sliding, which would cause interference between the two rib-side support components.

[0032] Furthermore, in order to enable the rib-side support assembly to slide stably left and right on the back support 2, the new chair back also includes a connector connected to each frame 23. The back support 1 is provided with a sliding groove 11 extending left and right, and the connector is slidably connected in the sliding groove 11. The connector is equivalent to the mounting carrier of the rib-side support assembly. By sliding the connector in the sliding groove 11, the rib-side support assembly can move in the left and right direction.

[0033] Furthermore, when the two rib-side support members 2 are far apart from each other and the support area is in the maximum support space, the two rib-side support members 2 cannot continue to be far apart from each other, so as to avoid the two rib-side support members 2 from dislodging from the slide groove 11. Specifically, the slide groove 11 includes limiting ends 111 on its left and right sides. When the two rib-side support members 2 are far apart from each other to the maximum width, the limiting ends 111 abut against the connecting member; so that the two rib-side support members 2 will not dislodge from the back support member 1 when they are in the maximum width.

[0034] Furthermore, the frame 23 is connected to the connector as follows: the connector is a U-shaped plate 25, the volume of which is smaller than that of the frame 23. A U-shaped groove 251 is formed on the U-shaped plate 25, and the frame 23 has a corresponding insert plate 231. The insert plate 231 is inserted into the U-shaped groove 251 and connected to the U-shaped plate 25 by screws. The U-shaped plate 25 occupies a small volume space and is less likely to affect the installation layout of other components. The U-shaped groove 251 can provide a guide for the insertion of the insert plate 231. After the insert plate 231 is inserted into the U-shaped groove 251, the screw connection also makes the connection between the insert plate 231 and the connector more stable.

[0035] Furthermore, at least one of the left and right rib-side support components is provided with a control adjustment mechanism between itself and the back support 1. In this embodiment, to ensure sufficient locking force for the rib-side support components on both sides, a control adjustment mechanism is provided between the rib-side support components on both sides and the back support 1. The control adjustment mechanism is configured to lock and unlock the position of the corresponding rib-side support component that moves left and right; to allow the corresponding rib-side support component to slide left and right for adjustment, and to allow the adjusted rib-side support component to stay in the corresponding position; specifically, the control adjustment mechanism includes a control adjustment mechanism between itself and the back support 1. The control lever 4 is connected to the component. The back support 1 is provided with multiple position sockets 13 arranged at intervals in the left and right direction for cooperating with the control lever 4. When the control lever 4 is disengaged from the corresponding position socket 13, the corresponding rib support 2 can move left and right and adjust the size of the support area. When the control lever 4 is inserted into the corresponding position socket 13, the corresponding rib support 2 can stay in the adjusted position. Thus, the process of locking and unlocking the position of the rib support component is simplified to a simple pulling process of the control lever 4, making the position adjustment and locking of the rib support component simple and efficient.

[0036] Furthermore, in order to lock and unlock the corresponding rib-side support components, the control rod 4 needs to be connected to the rib-side support components. Specifically, a U-shaped groove 251 is formed on the U-shaped plate 25. The U-shaped groove 251 is formed by two spaced flat plates 254 and a vertical plate 253 connected between the two flat plates 254. The opposite end of the vertical plate 253 has an outward opening. The frame 23 has a corresponding insert plate 231. The insert plate 231 is inserted into the U-shaped groove 251 through the opening and connected to the U-shaped plate 25 by screws. The insert plate 231 and the vertical plate 253 are separated by a distance, thus forming a guide groove 252 that communicates with the outside. The control rod 4 is inserted into the guide groove 252. The control rod 4 uses the space between the insert plate 231 and the vertical plate 253, so that the control rod 4 can slide left and right with the corresponding rib-side support components, thereby locking and unlocking the corresponding rib-side support components. The design is simple and the structure is ingenious.

[0037] Furthermore, although the control lever 4, which is inserted into the guide groove 252 and will separate from the gear position socket 13, is designed in a way that makes it easy for the control lever 4 to disengage from the guide groove 252 when pulled by external force and disengaged from the gear position socket 13, thus separating the control lever 4 from the rib-side support assembly. Therefore, to avoid this phenomenon, the control lever 4 has a side extension 41 extending inward from the back support 1 on its shaft. The side extension 41 is positioned opposite to the rib-side support 2. When the control lever 4 disengages from the corresponding gear position socket 13, the side extension 41 abuts against the rib-side support 2, forming a hook-like limit between the control lever 4 and the rib-side support 2, thus preventing the control lever 4 from falling off the rib-side support assembly when disengaged from the gear position socket 13.

[0038] Furthermore, the exposed frame 23 and sliding groove 11 on the back support 1 would affect the appearance of the chair back. Therefore, the front end of the back support 1 is connected to a back panel 5, which covers the front surface of the back support 1. The back panel 5 is provided with a clearance groove 51 to allow the frame 23 to move left and right. The back panel 1 forms a double-layer structure while covering the front surface of the back support 1. This not only hides the frame 23 in appearance, but also provides clearance space for the left and right sliding of the frame 23. The design is ingenious and achieves two goals at once.

[0039] Furthermore, the back plate 5 can also limit the connection of the connector. Specifically, each frame 23 is connected to a corresponding connector, which is a U-shaped plate 25. The back support 1 is provided with a sliding groove 11 extending to the left and right. The U-shaped plate 25 is slidably connected in the sliding groove 11. When the back plate 5 is connected to the front end of the back support 1, the rear end of the back plate 5 abuts against the front end of the U-shaped plate 25. At this time, the front and rear ends of the U-shaped plate 25 are in contact with the bottom of the back plate 1 and the sliding groove 11 respectively, preventing the connector from coming out of the sliding groove 11.

[0040] Furthermore, a soft pad 22 is connected to the support surface of the rib support 2; the soft pad 22 can provide a soft support feel to the ribs and improve the sitting experience.

[0041] Furthermore, in order to ensure that the size of the support area is within a reasonable range, the width between the two rib support members 2 varies from 240mm to 380mm; this range can ensure that the upper body of children or adults with different body shapes can be effectively supported at both ends of the ribs after sitting down.

[0042] Furthermore, a chair (not shown) is provided, including the novel chair back; when the user sits on the chair, the size of the support area can be adjusted to suit the user by pulling the side rib support 2, so that the side rib support 2 on both sides is always close to the side rib position, so as to play a role in waist correction.

[0043] 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 spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A novel chair back, characterized in that, include: Back support (1); used to provide support for the back; The rib-side support assembly is symmetrically arranged on the left and right sides of the back support member (1). The rib-side support assembly includes rib-side support members (2) and skeletons (23) that are connected to each other. The portion of the rib-side support member (2) that extends forward beyond the front end of the back support member (1) has a support surface. The two support surfaces are opposite to each other and a support area is formed between the two support surfaces. A toothed linkage structure is provided between the two skeletons (23). The toothed linkage structure includes a rack (24) on the skeleton (23) located inside the rib-side support member (2). The two racks (24) are staggered from left to right, and the teeth of the two racks (24) are simultaneously engaged with a linkage gear (3). An external force acts on one of the rib-side support members (2) and triggers the toothed linkage structure, causing the two rib-side support members (2) to move closer or further apart to adjust the size of the support area; and the two rib-side support members (2) after adjustment can stay in the corresponding position and remain in place.

2. The novel chair back according to claim 1, characterized in that: At least one end of the linkage gear (3) is connected to a rotating shaft (31), and the back support (1) is provided with a rotating shaft hole (12) corresponding to the position of the rotating shaft (31). The rotating shaft (31) is rotatably connected in the rotating shaft hole (12).

3. A novel chair back according to claim 1, characterized in that: The support area has a maximum support space and a minimum support space; The two rib-side supports (2) move closer to each other to the minimum width or further away from each other to the maximum width, so that the support area switches between the minimum support space and the maximum support space.

4. A novel chair back according to claim 3, characterized in that: The frame (23) includes a body and a rack (24) connected to the inner end of the body. The width of the body is greater than the width of the rack (24), and a stepped surface (232) is formed at the position where the body and the rack (24) are connected. The stepped surface (232) on one frame (23) is opposite to the end of the rack (24) on the other frame (23). When the two rib side supports (2) approach each other to the minimum width, the stepped surface (232) on one frame (23) abuts against the end of the rack (24) on the other frame (23).

5. A novel chair back according to claim 3, characterized in that: It also includes connectors that are connected to each skeleton (23) respectively, and the back support (1) is provided with a sliding groove (11) extending to the left and right, and the connectors are slidably connected in the sliding groove (11).

6. A novel chair back according to claim 5, characterized in that: The slide (11) includes limiting ends (111) on its left and right sides. When the two rib side supports (2) move away from each other to their maximum width, the limiting ends (111) abut against the connecting members.

7. A novel chair back according to claim 5, characterized in that: The connector is a U-shaped plate (25), on which a U-shaped groove (251) is formed. The frame (23) has a corresponding insert plate (231), which is inserted into the U-shaped groove (251) and connected to the U-shaped plate (25) by screws.

8. A novel chair back according to claim 1, characterized in that: At least one of the left-side rib support assembly and the right-side rib support assembly is provided with a control adjustment mechanism between itself and the back support member (1). The control adjustment mechanism is configured to lock and unlock the position of the corresponding left-right rib support assembly.

9. A novel chair back according to claim 8, characterized in that: The control adjustment mechanism includes a control lever (4) connected to the rib side support assembly. The back support (1) is provided with multiple gear slots (13) arranged at intervals in the left and right direction and used to cooperate with the control lever (4). When the control lever (4) is disengaged from the corresponding gear slot (13), the corresponding rib side support (2) can move left and right and adjust the size of the support area. When the control lever (4) is inserted into the corresponding gear slot (13), the corresponding rib side support (2) can stay in the corresponding adjusted position.

10. A novel chair back according to claim 9, characterized in that: Each frame (23) is connected to a corresponding U-shaped plate (25); a U-shaped groove (251) is formed on the U-shaped plate (25). The U-shaped groove (251) is formed by two spaced flat plates (254) and a vertical plate (253) connected between the two flat plates (254). The opposite end of the vertical plate (253) has an outward opening. The frame (23) has a corresponding insert plate (231). The insert plate (231) is inserted into the U-shaped groove (251) through the opening and connected to the U-shaped plate (25) by screws. The insert plate (231) is spaced from the vertical plate (253), thereby forming a guide groove (252) that communicates with the outside. The control rod (4) is inserted into the guide groove (252).

11. A novel chair back according to claim 9, characterized in that: The control lever (4) has a side extension (41) extending inward to the back support (1) on its shaft. The side extension (41) is opposite to the rib support (2). When the control lever (4) disengages from the corresponding gear hole (13), the side extension (41) abuts against the rib support (2), so that the control lever (4) and the rib support (2) form a hook limit.

12. A novel chair back according to claim 1, characterized in that: The back support member (1) is connected to a back plate (5) at the front end. The back plate (5) covers the front surface of the back support member (1), and the back plate (5) is provided with a clearance groove (51) for avoiding the left and right movement of the frame (23).

13. A novel chair back according to claim 12, characterized in that: Each frame (23) is connected to a corresponding connector, and the back support (1) is provided with a sliding groove (11) extending to the left and right. The connector is slidably connected in the sliding groove (11). When the back plate (5) is connected to the front end of the back support (1), the rear end of the back plate (5) abuts against the front end of the connector.

14. A novel chair back according to claim 1, characterized in that: A soft pad (22) is connected to the support surface of the rib side support (2).

15. A novel chair back according to claim 1, characterized in that: The width variation range between the two rib side supports (2) is 240mm-380mm.

16. A chair, characterized in that: Including the novel chair back as described in claim 1.

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