Chair back connecting structure applied to folding wheelchair

Abstract

A chair back connecting structure applied to a folding wheelchair comprises a chair seat connecting rod and a chair back connecting rod, the chair seat connecting rod and the chair back connecting rod are connected through a connecting assembly, and the connecting assembly comprises a chair seat connecting piece connected to the chair seat connecting rod and a chair back connecting piece connected to the chair back connecting rod; an adaptive groove is formed in the upper part of the chair seat connecting piece, two hinging parts are arranged at the rear end of the chair seat connecting piece, and a hinging arm hinged between the two hinging parts through a hinging shaft is arranged on the chair back connecting piece; the hinge arm is provided with an avoiding notch, a retaining torsional spring arranged in the middle of the hinge shaft in a sleeving mode is arranged in the avoiding notch, one torsional arm of the retaining torsional spring abuts against the hinge arm or / and the chair back connecting piece, and the other torsional arm of the retaining torsional spring abuts against the chair seat connecting piece. The chair back connecting piece cannot be overturned and swung at will by keeping the rotating force generated by the torsional spring, so that the wheelchair chair back is kept in a folded state, the stability of the wheelchair chair back in the folded state is improved, and the influence on carrying of the folded wheelchair after being folded is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of wheelchairs, and particularly relates to a backrest connection structure applied to a folding wheelchair. Background Art

[0002] In order to improve the flexibility of wheelchairs during transportation, more and more folding wheelchairs have emerged on the market.

[0003] An applicant previously proposed a backrest locking structure applied to a portable folding wheelchair disclosed in a Chinese patent with the publication number CN210408815U. It includes a seat, a backrest and a connection component. There are two connecting rods I on the seat, and two connecting rods II on the backrest. The connection component includes a connector I connected to the connecting rod I and a connector II connected to the connecting rod II. The connector I includes a sleeve installed on the connecting rod I and a fixing member arranged on the sleeve. The fixing member has a fixing hole and an opening, and connecting blocks are arranged on both sides of the opening. The connector II includes a hinge block and a fixing mechanism arranged on the hinge block. The hinge block has a hinge part hinged to the connecting block and a moving groove for installing the fixing mechanism. When the backrest is changed from the folded state to the unfolded state, the insertion pin shaft of the fixing mechanism can be connected to the fixing hole to lock the backrest in the unfolded state.

[0004] However, although this technical solution can lock the backrest in the unfolded state by using the insertion pin shaft of the fixing mechanism, there is no structure for locking the backrest in the folded state after the backrest is changed from the unfolded state to the folded state. As a result, when the folding wheelchair is carried after folding, the backrest swings relative to the seat, affecting the carrying of the folding wheelchair after folding. Summary of the Utility Model

[0005] In order to overcome the deficiencies of the prior art, the utility model provides a backrest connection structure applied to a folding wheelchair.

[0006] The technical solution adopted by the utility model to solve its technical problems is as follows:

[0007] A backrest connection structure applied to a folding wheelchair includes a seat connecting rod and a backrest connecting rod. The corresponding seat connecting rod and backrest connecting rod are connected by a connection component. The connection component includes a seat connector connected to the seat connecting rod and a backrest connector connected to the backrest connecting rod.

[0008] The upper part of the seat connecting member is provided with an adaptation groove that is open at both the upper end and the rear end. The rear end of the seat connecting member is provided with two hinge portions respectively located on the left and right sides of the rear opening of the adaptation groove. An articulated arm is provided on the backrest connecting member and is articulated between the two hinge portions by an articulated shaft. A fixing mechanism is provided on the backrest connecting member to keep the wheelchair backrest in an unfolded state after the backrest connecting member is flipped into the adaptation groove;

[0009] It is characterized in that: the articulated arm is provided with an avoidance notch that completely exposes the middle part of the articulated shaft. A retaining torsion spring is sleeved on the middle part of the articulated shaft in the avoidance notch. One torsion arm of the retaining torsion spring abuts against the articulated arm or / and the backrest connecting member, and the other torsion arm abuts against the seat connecting member.

[0010] In the present utility model, the seat connecting member has a torsion spring mating surface that closes the bottom of the adaptation groove, and the other torsion arm of the retaining torsion spring abuts against the torsion spring mating surface.

[0011] In the present utility model, the front end of the seat connecting member is provided with a connecting member through hole that communicates with the adaptation groove. The fixing structure includes a fixing pin head, a fixing compression spring, a driving wrench, and a linkage shaft. The front end of the backrest connecting member is provided with a fixing installation groove, and the rear groove surface of the fixing installation groove is provided with a limiting through hole that penetrates the rear end of the backrest connecting member;

[0012] The fixing pin head can move into and out of the fixing installation groove. A pin head guide shaft is provided at the rear end of the fixing pin head and is guided and fitted in the fixing installation groove;

[0013] The driving wrench is located at the rear end of the backrest connecting member and is provided with a linkage through hole corresponding to the limiting through hole;

[0014] The rear end of the linkage shaft is provided with a linkage limiting head that abuts against the back of the driving wrench. The front end sequentially passes through the linkage through hole and the limiting through hole and is combined and connected with the pin head guide shaft;

[0015] The fixing compression spring is arranged in the fixing installation groove and sleeved on the linkage shaft. The front end of the fixing compression spring abuts against the rear end of the pin head guide shaft, and the rear end abuts against the groove wall of the fixing installation groove.

[0016] In the present utility model, the front end portion of the linkage shaft is provided with a fixing thread section, and the rear end of the pin head guide shaft is provided with a fixing thread hole adapted to the fixing thread section. The fixing thread section is threadedly fitted in the fixing thread hole.

[0017] In the present utility model, the bottom surface of the seat connecting member is recessed upward to form a seat connecting groove, and the seat connecting rod is adapted to be within the seat connecting groove.

[0018] In the present utility model, the top view cross-sectional shapes of the seat connecting groove and the seat connecting rod are both D-shaped.

[0019] In the present utility model, the seat connecting member and the seat connecting rod are fixed by a steel ball pin. Opposite ends of the seat connecting member are respectively provided with a first pin hole and a second pin hole communicating with the seat connecting groove. Seat connecting holes corresponding to the first pin hole and the second pin hole are provided on the seat connecting rod, and one end of the steel ball pin sequentially passes through the first pin hole, the seat connecting hole, and the second pin hole.

[0020] In the present utility model, a backrest connecting groove is recessed downward on the top surface of the backrest connecting member, and the backrest connecting rod is adapted to be within the backrest connecting groove.

[0021] In the present utility model, the top view cross-sectional shapes of the backrest connecting groove and the backrest connecting rod are both D-shaped.

[0022] In the present utility model, a backrest locking structure is provided on the backrest connecting rod. The backrest locking structure includes a backrest connecting head, a backrest connecting pin, and a backrest locking compression spring. The backrest connecting head is fixed within the backrest connecting rod. A spring pin installation groove is provided within the backrest connecting head, and one end of the spring pin installation groove penetrates through the backrest connecting head.

[0023] A matching through hole corresponding to one end of the spring pin installation groove is provided on the backrest connecting rod. A backrest locking hole corresponding to the matching through hole is provided on the backrest connecting member. The backrest connecting pin is disposed within the spring pin installation groove. A backrest pin guide shaft protrudes in the middle of the backrest connecting pin. The backrest pin guide shaft divides the backrest connecting pin into a backrest pin main body and a backrest locking pin head. The backrest locking compression spring is sleeved on the backrest pin main body. One end of the backrest locking compression spring abuts against the groove surface of the spring pin installation groove, and the other end abuts against the backrest pin guide shaft.

[0024] The beneficial effects of the present utility model are as follows: A retaining torsion spring is provided on the hinge shaft. When the wheelchair backrest is in the unfolded state, the retaining torsion spring stores energy. During the process of the user converting the wheelchair backrest from the unfolded state to the folded state, the retaining torsion spring releases energy. One torsion arm of the retaining torsion spring rotates to push the backrest connecting member to rotate in the folding direction, thereby accelerating the speed of the wheelchair backrest converting from the unfolded state to the folded state. After the wheelchair backrest is converted to the folded state, the rotational force generated by the retaining torsion spring prevents the backrest connecting member from flipping and swinging arbitrarily, thereby keeping the wheelchair backrest in the folded state, improving the stability of the wheelchair backrest in the folded state, and reducing the impact on the handling of the folded wheelchair after folding. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present utility model will be further described below in conjunction with the drawings and embodiments:

[0026] Figure 1 For the three-dimensional structure of this embodiment Figure 1 ;

[0027] Figure 2 For the three-dimensional structure of this embodiment Figure 2 ;

[0028] Figure 3 is a schematic diagram of the internal structure of this embodiment. Detailed implementation manners

[0029] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model.

[0030] Referring to Figures 1-3 , a backrest connection structure applied to a folding wheelchair includes a seat connecting rod 1 and a backrest connecting rod 2. There are two seat connecting rods 1, which are respectively arranged on the left and right sides of the upper part of the rear end of the wheelchair seat. There are two backrest connecting rods 2, which are respectively arranged on the left and right sides of the bottom of the wheelchair backrest. Each seat connecting rod 1 corresponds to one backrest connecting rod 2. The corresponding seat connecting rod 1 and backrest connecting rod 2 are connected by a connection component. The connection component includes a seat connecting part 3 connected to the seat connecting rod 1 and a backrest connecting part 4 connected to the backrest connecting rod 2;

[0031] The upper part of the seat connecting part 3 is provided with an adaptation slot 31 with openings at both the upper end and the rear end. The rear end of the seat connecting part 3 is provided with two hinge parts 32 respectively located on the left and right sides of the rear opening of the adaptation slot 31. The backrest connecting part 4 is provided with a hinge arm 41 hinged between the two hinge parts 32 by a hinge shaft 5. The backrest connecting part 4 can enter and exit the adaptation slot 31 with the hinge shaft 5 as the rotation center. The backrest connecting part 4 is provided with a fixing mechanism for keeping the wheelchair backrest in the unfolded state after the backrest connecting part 4 is turned over and enters the adaptation slot 31.

[0032] Further, an avoidance notch 42 is provided on the articulated arm 41 to completely expose the middle part of the articulated shaft 5. The avoidance notch 42 runs through the articulated arm 41 from front to back. A retaining torsion spring 6 is sleeved on the middle part of the articulated shaft 5 in the avoidance notch 42. One torsion arm of the retaining torsion spring 6 abuts against the articulated arm 41 or / and the backrest connecting member 4, and the other torsion arm of the retaining torsion spring 6 abuts against the seat connecting member 3. In this embodiment, one torsion arm of the retaining torsion spring 6 abuts against the bottom of the backrest connecting member 4. The seat connecting member 3 has a torsion spring mating surface 30 that closes the bottom of the fitting groove 31. The other torsion arm of the retaining torsion spring 6 abuts against the torsion spring mating surface 30, so that the two torsion arms of the retaining torsion spring 6 can better drive the backrest connecting member 4 to flip and fold relative to the seat connecting member 3.

[0033] In this embodiment, a retaining torsion spring 6 is provided on the articulated shaft 5. When the wheelchair backrest is in the unfolded state, the retaining torsion spring 6 stores energy. During the process of the user converting the wheelchair backrest from the unfolded state to the folded state, the retaining torsion spring 6 releases energy. One torsion arm of the retaining torsion spring 6 rotates to push the backrest connecting member 4 to rotate in the folding direction, thereby accelerating the speed of the wheelchair backrest converting from the unfolded state to the folded state. After the wheelchair backrest is converted to the folded state, the rotational force generated by the retaining torsion spring 6 prevents the backrest connecting member 4 from arbitrarily flipping and swinging, so that the wheelchair backrest remains in the folded state, improving the stability of the wheelchair backrest in the folded state and reducing the impact on the handling of the folded wheelchair after folding.

[0034] As a preferred embodiment, a connecting member through hole 33 communicating with the fitting groove 31 is provided at the front end of the seat connecting member 3. The fixing structure 7 includes a fixing pin head 71, a fixing compression spring 72, a driving wrench 73 and a linkage shaft 74. A fixing installation groove 43 extending backward is provided at the front end of the backrest connecting member 4, and a limiting through hole penetrating through the rear end of the backrest connecting member 4 is provided on the rear groove surface of the fixing installation groove 43;

[0035] The fixing pin head 71 can move into and out of the fixing installation groove 43. A pin head guide shaft 711 that is integrally formed at the rear end of the fixing pin head 71 is guidingly fitted in the fixing installation groove 43. The outer peripheral surface of the pin head guide shaft 711 is slidably fitted with the outer circular groove surface of the fixing installation groove 43, so that the pin head guide shaft 711 guides the movement of the fixing pin head 71;

[0036] The driving wrench 73 is located at the rear end of the seat back connector 4 and is provided with a linkage through hole corresponding to the limiting through hole; the rear end of the linkage shaft 74 is provided with a linkage limiting head 741 that abuts against the back of the driving wrench 73, and the front end passes through the linkage through hole and the limiting through hole in sequence and is combined and connected with the pin head guide shaft 711. For example, the front end of the linkage shaft 74 is provided with a fixed threaded section, and the rear end of the pin head guide shaft 711 is provided with a fixed threaded hole adapted to the fixed threaded section, and the fixed threaded section is threadedly fitted in the fixed threaded hole, so that the linkage shaft 74 and the fixed pin head 71 are combined and fixed together;

[0037] Furthermore, to facilitate the connection between the linkage shaft 74 and the pin guide shaft 711, a hexagonal groove 742 is provided on the rear end of the linkage stopper 741, allowing for easy connection by turning the linkage shaft 74 with a hexagonal wrench. Furthermore, to enhance the fit between the fixed threaded section and the fixed threaded hole, a filler layer formed by cured screw glue is provided between the exterior of the fixed threaded section and the fixed threaded hole.

[0038] The fixed compression spring 72 is arranged in the fixed installation groove 43 and is sleeved on the linkage shaft 74. The front end of the fixed compression spring 72 abuts on the rear end of the pin head guide shaft 711, and the rear end abuts on the groove wall of the fixed installation groove 43; when the seat back connector 4 flips over and enters the adapter groove 31, the fixed compression spring 72 drives the fixed pin head 71 to extend out of the fixed installation groove 43 and enter the connector through hole 33 through elastic force, thereby limiting the seat back connector 4 from flipping and folding backward, thereby achieving the purpose of keeping the wheelchair back in an unfolded state; by turning the drive wrench 73, the linkage shaft 74 can drive the fixed pin head 71 to retract and exit the connector through hole 33, so that the seat back connector 4 can flip and fold backward, allowing the user to fold the wheelchair back. In addition, since the retaining torsion spring 6 will store energy after the backrest connector 4 flips into the adapter slot 31, when the user is not pushing the wheelchair backrest in the unfolding direction by hand, the retaining torsion spring 6 will generate a rotational force to rotate the wheelchair backrest in the folding direction. At this time, under these rotational forces, the outer side of the fixing pin head 71 abuts against the hole wall of the connector through hole 33, thereby forming friction resistance, reducing the probability of the fixing pin head 71 exiting the connector through hole 33 when the user does not turn the drive wrench 73, thereby ensuring the stability of the wheelchair backrest in the unfolded state.

[0039] As a preferred embodiment, the bottom surface of the seat connector 3 is recessed upward to form a seat connection groove, and the seat connection rod 1 fits within the seat connection groove, thereby assembling and connecting the seat connection rod 1 and the seat connector 3. Furthermore, the seat connection groove and the seat connection rod 1 are both D-shaped in cross-section when viewed from above. This structure prevents the seat connector 3 from rotating relative to the seat connection rod 1, thereby improving the positioning quality of the seat connector 3 when installed on the seat connection rod 1.

[0040] Furthermore, the seat connecting member 3 and the seat connecting rod 1 are fixed by a steel ball pin 8. The opposite ends of the seat connecting member 3 are respectively provided with a first pin hole and a second pin hole communicating with the seat connecting groove. The seat connecting rod 1 is provided with seat connecting holes corresponding to the first pin hole and the second pin hole. One end of the steel ball pin 8 sequentially passes through the first pin hole, the seat connecting hole and the second pin hole, so that the seat connecting member 3 and the seat connecting rod 1 are combined and fixed together, completing the fixed connection between them. This connection structure is simple and can realize the quick disassembly and assembly between the seat connecting member 3 and the seat connecting rod 1, effectively improving the disassembly efficiency between them. The steel ball pin 8 is a pin component that can be purchased on the existing market, so its specific structure will not be described.

[0041] As a preferred embodiment, the top surface of the backrest connecting member 4 is recessed downward to form a backrest connecting groove, and the backrest connecting rod 2 is adapted to be within the backrest connecting groove, so that the backrest connecting rod 2 and the backrest connecting member 4 are combined and connected together. Further, the top view cross-sectional shapes of the backrest connecting groove and the backrest connecting rod 2 are both D-shaped. With this structure, the backrest connecting member 4 cannot be rotated relative to the backrest connecting rod 2, thereby improving the positioning quality of the backrest connecting member 4 installed on the backrest connecting rod 2.

[0042] Furthermore, the backrest connecting rod 2 is provided with a backrest locking structure 9. The backrest locking structure 9 includes a backrest connecting head 91, a backrest connecting pin 92, and a backrest locking compression spring 93. The backrest connecting head 91 is fixed within the backrest connecting rod 2. The backrest connecting head 91 is provided with a spring pin installation groove, and one end of the spring pin installation groove penetrates through the backrest connecting head 91; the backrest connecting rod 2 is provided with a mating through hole corresponding to one end of the spring pin installation groove, and the backrest connecting member 4 is provided with a backrest locking hole 44 corresponding to the mating through hole. The backrest connecting pin 92 is disposed within the spring pin installation groove. A backrest pin guide shaft 921 is convexly provided in the middle of the backrest connecting pin 92. The backrest pin guide shaft 921 divides the backrest connecting pin 92 into a backrest pin main body and a backrest locking pin head. The backrest locking compression spring 93 is sleeved on the backrest pin main body. One end of the backrest locking compression spring 93 abuts against the groove surface of the spring pin installation groove, and the other end abuts against the backrest pin guide shaft 921; the outer diameter of the backrest pin guide shaft 921 is larger than the mating through hole, so that the backrest pin guide shaft 921 can limit the moving stroke of the backrest connecting pin 92; the outer peripheral surface of the backrest pin guide shaft 921 is slidably mated with the groove surface of the spring pin installation groove to guide the movement of the backrest connecting pin 92.

[0043] After the backrest connecting rod 2 is fitted into the backrest connection groove, the backrest locking pin head extends into the backrest locking hole 44 under the elastic force of the backrest locking compression spring 93, so that the backrest connecting rod 2 cannot easily come out of the backrest connection groove, thus completing the quick combination and fixation between the backrest connecting rod 2 and the backrest connecting member 4. This structure does not require tools such as wrenches or screwdrivers to tighten the connection position between the backrest connecting rod 2 and the backrest connecting member 4. Moreover, when the backrest connecting rod 2 and the backrest connecting member 4 are separated, only by pressing the backrest locking pin head to make the backrest locking pin head withdraw from the backrest locking hole 44 can the unlocking between the backrest connecting rod 2 and the backrest connecting member 4 be realized, enabling them to be separated. This method effectively improves the disassembly and assembly efficiency between the backrest connecting rod 2 and the backrest connecting member 4, facilitating the user to disassemble the backrest from the backrest connecting member 4 in the later stage and then disassemble the backrest cloth pad on the backrest for cleaning. Of course, it is not limited to the above structure. In other embodiments, the backrest locking structure 9 can be a backrest connection bolt. A mating screw hole is provided on the backrest connecting rod 2, and a mating through hole corresponding to the mating screw hole is provided on the backrest connecting member 4. The screw rod section of the backrest connection bolt passes through the mating through hole and is threadedly fitted in the mating screw hole, and the combination and fixation between the backrest connecting rod 2 and the backrest connecting member 4 can also be realized.

[0044] The above are only the preferred embodiments of the present invention. As long as the technical solutions that achieve the purpose of the present invention by basically the same means fall within the protection scope of the present invention.

Claims

1. A seat back connection structure for a folding wheelchair, comprising a seat connecting rod (1) and a seat back connecting rod (2), wherein the seat connecting rod (1) and the seat back connecting rod (2) corresponding to each other are connected via a connecting assembly, wherein the connecting assembly comprises a seat connecting piece (3) connected to the seat connecting rod (1) and a seat back connecting piece (4) connected to the seat back connecting rod (2); The upper portion of the seat connector (3) is provided with an adapting groove (31) with openings at both the upper end and the rear end. The rear end of the seat connector (3) is provided with two hinged portions (32) respectively located on the left and right sides of the rear end opening of the adapting groove (31). The backrest connector (4) is provided with an articulated arm (41) articulated between the two articulated portions (32) by a hinge shaft (5). The backrest connector (4) is provided with a fixing mechanism for keeping the wheelchair backrest in an unfolded state after the backrest connector (4) is flipped into the adapting groove (31). Its characteristics are: The hinge arm (41) is provided with an avoidance notch (42) that completely exposes the middle of the hinge shaft (5), and a retaining torsion spring (6) sleeved on the middle of the hinge shaft (5) is provided in the avoidance notch (42), one torsion arm of the retaining torsion spring (6) abuts against the hinge arm (41) and / or the chair back connector (4), and the other torsion arm abuts against the chair seat connector (3).

2. The seat back connection structure for a folding wheelchair according to claim 1, characterized in that: The seat connector (3) has a torsion spring matching surface (30) that closes the bottom of the adapting groove (31), and the other torsion arm of the retaining torsion spring (6) abuts against the torsion spring matching surface (30).

3. The seat back connection structure for a folding wheelchair according to claim 1, characterized in that: The front end of the seat connector (3) is provided with a connector through hole (33) communicating with the adapter groove (31); the fixing mechanism (7) includes a fixing pin (71), a fixing compression spring (72), a driving wrench (73) and a linkage shaft (74); the front end of the chair back connector (4) is provided with a fixing installation groove (43); the rear groove surface of the fixing installation groove (43) is provided with a limiting through hole penetrating the rear end of the chair back connector (4); The fixed pin head (71) is capable of moving into and out of the fixed installation slot (43), and the rear end of the fixed pin head (71) is provided with a pin head guide shaft (711) that is guided and engaged in the fixed installation slot (43); The driving wrench (73) is located at the rear end of the chair back connector (4) and is provided with a linkage through hole corresponding to the limiting through hole; The rear end of the linkage shaft (74) is provided with a linkage limit head (741) that abuts against the back of the driving wrench (73), and the front end passes through the linkage through hole and the limit through hole in sequence and is assembled and connected with the pin head guide shaft (711); The fixed compression spring (72) is arranged in the fixed installation groove (43) and is sleeved on the linkage shaft (74). The front end of the fixed compression spring (72) abuts against the rear end of the pin guide shaft (711), and the rear end abuts against the groove wall of the fixed installation groove (43).

4. The seat back connection structure for a folding wheelchair according to claim 3, characterized in that: The front end of the linkage shaft (74) is provided with a fixed threaded section, and the rear end of the pin guide shaft (711) is provided with a fixed threaded hole adapted to the fixed threaded section, wherein the fixed threaded section is threadably engaged in the fixed threaded hole.

5. A seat back connection structure for a folding wheelchair according to any one of claims 1 to 4, characterized in that: The bottom surface of the seat connecting piece (3) is recessed upwards to provide a seat connecting groove, and the seat connecting rod (1) is adapted to fit into the seat connecting groove.

6. The seat back connection structure for a folding wheelchair according to claim 5, characterized in that: The top-view cross-sectional shapes of the seat connection groove and the seat connection rod (1) are both D-shaped.

7. The seat back connection structure for a folding wheelchair according to claim 5, characterized in that: The seat connecting member (3) and the seat connecting rod (1) are fixed by a steel ball pin (8), and the opposite ends of the seat connecting member (3) are respectively provided with a first pin hole and a second pin hole connected to the seat connecting groove, and the seat connecting rod (1) is provided with a seat connecting hole corresponding to the first pin hole and the second pin hole, and one end of the steel ball pin (8) passes through the first pin hole, the seat connecting hole and the second pin hole in sequence.

8. The seat back connection structure for a folding wheelchair according to any one of claims 1 to 4, characterized in that: The top surface of the chair back connecting piece (4) is recessed downwards to provide a chair back connecting groove, and the chair back connecting rod (2) is adapted to fit into the chair back connecting groove.

9. The seat back connection structure for a folding wheelchair according to claim 8, characterized in that: The top-view cross-sectional shapes of the seat back connection groove and the seat back connection rod (2) are both D-shaped.

10. The seat back connection structure for a folding wheelchair according to claim 8, characterized in that: The backrest connecting rod (2) is provided with a backrest locking structure (9), the backrest locking structure (9) comprises a backrest connecting head (91), a backrest connecting pin (92), and a backrest locking compression spring (93), the backrest connecting head (91) is fixed in the backrest connecting rod (2), a spring pin mounting groove is provided in the backrest connecting head (91), and one end of the spring pin mounting groove passes through the backrest connecting head (91); The backrest connecting rod (2) is provided with a matching through hole corresponding to one end of the elastic pin mounting groove, and the backrest connecting member (4) is provided with a backrest locking hole (44) corresponding to the matching through hole. The backrest connecting pin (92) is provided in the elastic pin mounting groove, and a backrest pin guide shaft (921) is provided on the middle protrusion of the backrest connecting pin (92). The backrest pin guide shaft (921) divides the backrest connecting pin (92) into a backrest pin body and a backrest locking pin head. The backrest locking compression spring (93) is sleeved on the backrest pin body, and one end of the backrest locking compression spring (93) is against the groove surface of the elastic pin mounting groove, and the other end is against the backrest pin guide shaft (921).

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