Training chair with anti-toppling function

Abstract

A training chair with an anti-toppling function comprises a front supporting leg, a rear supporting leg and a chair seat, and the front supporting leg comprises a front seat rod and front chair legs fixedly arranged at the left end and the right end of the front seat rod respectively; the rear supporting legs comprise a rear seat rod and rear chair legs which are fixedly arranged at the left end and the right end of the rear seat rod respectively, and the rear chair legs are rotationally connected with the front chair legs; the chair seat comprises a seat shell, a rotating groove is formed in the bottom of the seat shell, and a bottom shell limiting seat is further mounted on the seat shell; a folding lock hole is formed in the rear seat rod, a folding locking guide groove is formed in the bottom shell limiting seat, a folding maintaining mechanism is arranged in the folding locking guide groove and comprises a folding locking block and a folding spring, and the folding locking block is configured to rotate around the rear seat rod along with overturning of the seat. When the folding locking block directly faces the folding lock hole, the folding locking block is clamped into the folding lock hole under the elastic action of the folding spring, so that the phenomenon that the seat of the training chair is overturned, toppled and opened in the folded state is not easy to occur without external force operation, and the normal folding storage of the training chair is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to training chair technical field, concretely relates to a training chair with prevent dumping function. BACKGROUND

[0002] In order to conveniently store, the training chair on the market currently usually has folding function. For example, the technical scheme disclosed by CN202321273355.9 discloses a foldable training chair, which comprises a chair frame and a chair cushion. The chair frame comprises mutually symmetrical supports, the supports comprise support one and support two which are cross-rotationally connected, the mutually symmetrical supports one are fixedly connected with a rotating shaft rod between them, the rotating shaft rod is sleeved with the chair cushion, the chair cushion is rotationally connected with the rotating shaft rod, the mutually symmetrical supports two are fixedly connected with a cross bar between them, and the bottom of the chair cushion is provided with a clamping groove which is clamped with the cross bar. When the chair cushion is rotated to the horizontal position, the cross bar can be clamped with the clamping groove, at this time, the support one and the support two cannot be relatively rotated, thereby locking the support, so that the training chair remains in the unfolded state, and it is convenient for users to sit.

[0003] In the technical scheme, the training chair is limited to remain in the unfolded state by the clamping groove and the cross bar, and it is convenient for users to sit. After the user uses the training chair, the training chair is usually folded for storage. However, the technical scheme does not provide a mechanism for keeping the training chair in the folded state, and the seat of the training chair in the folded state is prone to be turned over and opened during the movement of the user, thereby affecting the normal folding and storage of the training chair. UTILITY MODEL CONTENTS

[0004] In order to overcome the defects of the prior art, the utility model provides a training chair with a dumping prevention function.

[0005] The utility model solves the technical problems by adopting the following technical scheme:

[0006] A training chair with a dumping prevention function, comprising a front support leg, a rear support leg and a seat, the front support leg comprises a front seat rod and front chair legs respectively fixed on the left and right ends of the front seat rod, the rear support leg comprises a rear seat rod and rear chair legs respectively fixed on the left and right ends of the rear seat rod, and the rear chair legs and the front chair legs are rotationally connected, the seat comprises a seat shell, the bottom of the seat shell is provided with a rotating groove, and a bottom shell limiting seat for limiting the rear seat rod in the rotating groove is further arranged on the seat shell, characterized in that a folding locking hole is arranged on the rear seat rod, a folding locking guide groove is arranged on the bottom shell limiting seat, a folding retaining mechanism capable of limiting and keeping the seat in the folded state is arranged in the folding locking guide groove, the folding retaining mechanism comprises a folding locking block for inserting into the folding locking hole to limit the turning of the seat and a folding spring for driving the folding locking block to move towards the rear seat rod in an elastic manner, and the folding locking block is configured to rotate around the rear seat rod as the seat turns.

[0007] In the utility model, the middle part of the backrest rod is sleeved with a folding locking seat, the folding locking seat is equipped with a sliding arc surface for sliding contact of the folding locking block, and the folding locking hole is arranged on the sliding arc surface of the folding locking seat.

[0008] In the utility model, the folding locking seat is equipped with a seat rod adapting groove for matching the external shape of the backrest rod, and the folding locking seat and the backrest rod are combined and connected through bolt connection.

[0009] In the utility model, the folding locking block comprises a folding locking block and a folding locking inserting part which are integrally connected in sequence, the folding locking inserting part is provided with a hole-exit guide inclined surface, and the hole-exit guide inclined surface is used for pressing the wall surface of the folding locking hole in the chair seat unfolding process to make the folding locking inserting part exit the folding locking hole.

[0010] In the utility model, the folding locking block is provided with a folding spring groove, one end of the folding spring is inserted into the folding spring groove, and the other end is pressed on the groove wall of the folding locking guide groove.

[0011] In the utility model, the seat shell is also provided with a corresponding rotating groove, a seat rod limiting groove, a bottom shell limiting seat installed in the seat rod limiting groove, a first rotating adapting groove arranged on the bottom shell limiting seat, a second rotating adapting groove arranged on the groove surface of the seat rod limiting groove, and a rotating adapting hole formed by the combination of the first rotating adapting groove and the second rotating adapting groove and used for forming rotating cooperation with the backrest rod.

[0012] In the utility model, the upper part of the bottom shell limiting seat is provided with an installation limiting plate covering the upper end opening of the folding locking guide groove.

[0013] In the utility model, the bottom of the installation limiting plate is provided with an upper guide convex rail, the groove bottom surface of the folding locking guide groove is provided with a lower guide convex rail, the upper part of the folding locking block is provided with an upper guide sliding groove slidably matched with the upper guide convex rail, and the lower part of the folding locking block is provided with a lower guide sliding groove slidably matched with the lower guide convex rail.

[0014] In the utility model, the training chair further comprises a chair back, a chair back frame is commonly installed on the two front chair legs, a height lock seat is arranged on the chair back frame, a lifting sliding seat which can be lifted and slid is guidingly installed on the height lock seat, and the chair back is installed on the front end of the lifting sliding seat.

[0015] In the utility model, the height locking mechanism includes height locking shaft, height locking piece and height spring, both ends of the height locking shaft are respectively matched and installed in two articulated long holes, the height locking shaft can be lifted and moved along the length direction of the articulated long hole, the upper end of the height locking piece is connected on the height locking shaft, the lower end of the height locking piece is equipped with height lock portion for being clamped into the height clamping groove to lock the height of the chair back on one side, the height spring is used for driving the lower end of the height locking piece to rotate towards the height clamping groove with the height locking shaft as the rotation center.

[0016] The utility model discloses the beneficial effect has: the utility model discloses being equipped with folding locking guide groove on the bottom shell limit seat, be equipped with folding keeping mechanism in the folding locking guide groove, folding keeping mechanism includes the folding locking block for inserting into folding lock hole and limiting chair seat overturning folding spring of driving folding locking block to move to rear seat pole direction with elasticity, folding locking block is configured as rotating around rear seat pole with chair seat overturning, and when folding locking block is opposite folding lock hole, folding locking block is clamped into folding lock hole under the elasticity of folding spring, thereby limiting chair seat folding and overturning dump unfolding after this, so that the training chair under the folding state is not easy to appear chair seat overturning dump opening phenomenon under no external force operation, guarantee the normal folding of training chair and storage. BRIEF DESCRIPTION OF DRAWINGS

[0017] The utility model is further explained in connection with the drawings and implementation:

[0018] Figure 1 For the three-dimensional of training chair Figure 1 ;

[0019] Figure 2 For the three-dimensional of training chair Figure 2 ;

[0020] Figure 3 For the schematic view of seat shell;

[0021] Figure 4 For the combined section view of folding keeping mechanism and seat shell;

[0022] Figure 5 For the exploded schematic view of folding keeping mechanism and seat shell;

[0023] Figure 6 For the exploded schematic view of folding keeping mechanism;

[0024] Figure 7 For the combined schematic view of chair back and chair back frame;

[0025] Figure 8 is a disassembled view of the chair back and height locking mechanism;

[0026] Figure 9 is an assembled view of the height locking mechanism. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model.

[0028] Referring to Figures 1-9 A training chair with anti-toppling function, comprising front legs, rear legs and a seat, the front legs comprise front seat rods 11 and front chair legs 12 respectively fixed on the left and right ends of the front seat rods 11 by welding; the rear legs comprise rear seat rods 21 and rear chair legs 22 respectively fixed on the left and right ends of the rear seat rods 21 by welding, the rear chair legs 22 and the front chair legs 12 on the same side of the training chair are connected by a hinge device, the hinge device is a conventional mechanism of the existing training chair, so it is not described in detail.

[0029] Further, the seat comprises a seat shell 31 and a seat cushion arranged on the upper part of the seat shell 31, the bottom of the seat shell 31 is provided with a rotating groove 32, and the rear seat rod 21 is partially rotatably matched in the rotating groove 32; a bottom shell limiting seat 4 for limiting the rear seat rod 21 in the rotating groove 32 is installed on the seat shell 31, specifically; the seat shell 31 is also provided with a corresponding rotating groove 32 communicating seat rod limiting groove 33, and the bottom shell limiting seat 4 is installed in the seat rod limiting groove 33.

[0030] Still further, the rear seat rod 21 is provided with a folding locking hole 50, the bottom shell limiting seat 4 is provided with a folding locking guide groove 41, the folding locking guide groove 41 is provided with a folding retaining mechanism capable of limiting and retaining the seat in a folded state, the folding retaining mechanism comprises a folding locking block 51 for inserting into the folding locking hole 50 to limit the seat from turning over and a folding spring 52 for driving the folding locking block 51 to move towards the rear seat rod 21 by elasticity, the folding locking block 51 is configured to rotate around the rear seat rod 21 as the seat turns over, and when the folding locking block 51 is opposite to the folding locking hole 50, the folding locking block 51 is clamped into the folding locking hole 50 under the elastic action of the folding spring 52, so as to limit the seat from turning over and unfolding after folding, so that the training chair in the folded state is not easy to appear the phenomenon of the seat turning over and opening without external force, and the normal folding and storage of the training chair is ensured. When it is necessary to turn over and open the seat, the user only needs to force the seat to make the folding locking block 51 disengage from the folding locking hole 50.

[0031] As a preferred implementation, the middle part of the back rod 21 is sleeved with a folding locking seat 53, the folding locking seat 53 is provided with a sliding arc surface for sliding contact of the folding locking block 51, and the folding locking hole 50 is arranged on the sliding arc surface of the folding locking seat 53. By arranging the folding locking seat 53 and the folding locking block 51 in cooperation, the folding locking block 51 can avoid continuous friction on the surface of the back rod 21, thereby reducing the probability of wear of the back rod 21 and ensuring stable use of the back rod 21. Further, the folding locking seat 53 is provided with a rod fitting groove matched with the external shape of the back rod 21, so that the folding locking seat 53 can be better installed on the back rod 21, and the folding locking seat 53 and the back rod 21 are combined and connected by bolt connection.

[0032] As a preferred implementation, the folding locking block 51 comprises a folding locking block 511 and a folding locking plug 512 connected in sequence and integrally formed, the folding locking block 511 is provided with a folding spring groove, one end of the folding spring 52 is inserted into the folding spring groove, and the other end is pressed against the groove wall of the folding locking guide groove 41, so that the two ends of the folding spring 52 are combined and connected with the folding locking block 511 and the bottom shell limiting seat 4 respectively; the cross-sectional shape of the folding locking plug 512 is trapezoidal, so as to facilitate the folding locking plug 512 to enter and exit the folding locking hole 50, and the end of the folding locking plug 512 away from the folding locking block 511 can slide on the sliding arc surface. In this embodiment, since the cross-sectional shape of the folding locking plug 512 is trapezoidal, the folding locking plug 512 has a hole removal guide slope 513 thereon, which is used to press against the wall surface of the folding locking hole 50 during unfolding of the seat to promote the folding locking plug 512 to exit the folding locking hole 50, so that the seat can be normally unfolded by the user.

[0033] As a preferred implementation, in order to improve the stability of the middle part of the back rod 21, the bottom shell limiting seat 4 is provided with a first rotation fitting groove 42, the middle part of the back rod 21 is rotatably fitted in the first rotation fitting groove 42, the groove surface of the rod limiting groove 33 is provided with a second rotation fitting groove 34 corresponding to the first rotation fitting groove 42, and the first rotation fitting groove 42 and the second rotation fitting groove 34 are combined to form a rotation fitting hole, so as to form a rotating fit with the back rod 21 by using the rotation fitting hole.

[0034] In the embodiment, the upper part of the bottom shell limiting seat 4 is provided with an installation limiting plate 54, which covers the upper end opening of the folding locking guide slot 41, so as to limit the folding locking block 51 from moving up and down. The bottom of the installation limiting plate 54 is provided with an upper guide convex rail 541, the bottom surface of the folding locking guide slot 41 is provided with a lower guide convex rail 44, the upper part of the folding locking block 51 is provided with an upper guide sliding groove which is slidably matched with the upper guide convex rail 541, and the lower part of the folding locking block 51 is provided with a lower guide sliding groove which is slidably matched with the lower guide convex rail 44. The above structure can guide the folding locking block 51.

[0035] As a preferred embodiment, the bottom of the seat shell 31 is provided with a matching groove 35 for inserting the front seat rod 11 after the chair seat is unfolded, and an unfolding lock mechanism for limiting the front seat rod 11 in the matching groove 35 to lock the chair seat in the unfolded state is installed on the seat shell 31. The unfolding lock mechanism comprises an unfolding lock 61 which is guided and installed on the seat shell 31 and an unfolding tension spring 62 which is used to drive the unfolding lock 61 to slide below the matching groove 35 by elasticity. The two ends of the unfolding tension spring 62 are respectively connected with the seat shell 31 and the unfolding lock 61. The unfolding lock 61 is provided with a control handle for controlling the sliding of the unfolding lock 61 and an unfolding driving cam surface 611 for forcing the unfolding lock 61 to slide away from the matching groove 35 during the unfolding of the chair seat. The unfolding lock 61 is configured to slide to the matching groove 35 under the elastic driving of the unfolding tension spring 62 to limit the front seat rod 11 in the matching groove 35, so that the training chair is stably kept in the unfolded state.

[0036] As a preferred embodiment, the training chair further comprises a chair back 7, and a chair back frame 71 is commonly installed on the two front chair legs 12. The chair back frame 71 is provided with a height lock seat 72, and a lifting sliding seat 73 which can slide up and down is guided and installed on the height lock seat 72. The chair back 7 is installed on the front end of the lifting sliding seat 73. The lifting sliding seat 73 is provided with a height locking mechanism for limiting the height of the lifting sliding seat 73 on the height lock seat 72. The combination of the lifting sliding seat 73 and the height locking mechanism enables the training chair to have the height adjustment function of the chair back 7, which can meet the different use requirements of the user for the chair back 7.

[0037] In the embodiment, the height lock seat 72 is provided with two lifting guide holes 721 arranged from left to right. The lifting guide holes 721 are long circular holes which penetrate the height lock seat 72 from front to back. The length direction of the lifting guide holes 721 extends from top to bottom, and each lifting guide hole 721 corresponds to one lifting sliding seat 73. The lifting sliding seat 73 is slidably matched in the lifting guide hole 721. The rear end of the lifting sliding seat 73 is provided with a lifting limiting slide block which limits the forward movement of the lifting sliding seat 73. The front end of the lifting sliding seat 73 extends out of the lifting guide hole 721 and is connected with the chair back 7 by means of bolt connection.

[0038] Further, a plurality of height clamping grooves 722 are arranged on a vertical hole wall of the lifting guide hole 721 from top to bottom, the lifting slide 73 is provided with a locking installation groove 731 and a hinged long hole 732 on both sides of the locking installation groove 731, the hinged long hole 732 is a long circular hole, the length direction of the hinged long hole 732 is parallel to the lifting direction of the chair back 7; the height locking mechanism is located in the locking installation groove 731, the height locking mechanism comprises a height locking shaft 74, a height locking piece 75 and a height spring 76, both ends of the height locking shaft 74 are respectively fitted and installed in the two hinged long holes 732, the height locking shaft 74 can be lifted and moved along the length direction of the hinged long hole 732, the hinged long hole 732 is provided with a limiting plug 77, the height locking shaft 74 is located between the limiting plugs 77 of the two hinged long holes 732, so as to not move forward and backward out of the hinged long hole 732; the upper end of the height locking piece 75 is connected to the height locking shaft 74, the lower end of the height locking piece 75 can rotate and swing around the height locking shaft 74 as the center, one side of the lower end of the height locking piece 75 is provided with a height locking part 751 for clamping into the height clamping groove 722 to lock the height of the chair back 7, the cross-sectional shape of the height clamping groove 722 and the height locking part 751 is a trapezoidal shape; one end of the height spring 76 is installed in the spring groove of the height locking piece 75, the other end is fitted on the groove wall of the locking installation groove 731, the height spring 76 is used to drive the lower end of the height locking piece 75 to rotate towards the height clamping groove 722 around the height locking shaft 74 as the center.

[0039] Further, the bottom of the height locking piece 75 is provided with an unlocking retaining groove 752, the bottom of the locking installation groove 731 is provided with an unlocking retaining part 733 which can be inserted into the unlocking retaining groove 752 during the resetting process of the chair back 7; the other vertical hole wall of the lifting guide hole 721 is provided with a first limiting part 723 and a second limiting part 724 arranged from top to bottom, the other side of the lower end of the height locking piece 75 is provided with a linkage protruding part 753 for limiting the upward movement of the height locking piece 75 by cooperating with the first limiting part 723 during the upward movement of the chair back 7 and limiting the downward movement of the height locking piece 75 by cooperating with the second limiting part 724 during the downward movement of the chair back 7.

[0040] When adjusting the height of the chair back 7, pull the chair back 7 upward, the chair back 7 linkage lifting slide 73 and the height locking piece 75 move upward synchronously, in this process, the lower end of the height locking piece 75 continuously swings around the height locking shaft 74 as the center to make the height locking part 751 cooperate with different height clamping grooves 722, when the height locking part 751 cooperates with the height clamping groove 722 and the chair back 7 is not pulled any more, the height of the chair back 7 is locked and cannot be reset downward.

[0041] When it is needed to reset to the lowest level, the chair back 7 is continuously pulled to move upward, when the height locking part 75 rises over the highest one of the height locking slots 722, the lower end of the height locking part 75 rotates around the height locking shaft 74 to approach the other vertical hole wall of the lifting guide hole 721, and the linkage convex part 753 is inserted between the first limiting part 723 and the second limiting part 724, until the linkage convex part 753 abuts on the first limiting part 723, the height locking part 75 is limited to continuously move upward, at this time, the chair back 7 and the lifting slide 73 continuously move upward, while the height locking part 75 and the height locking shaft 74 remain unchanged, when the unlocking retaining part 733 is inserted in the unlocking retaining slot 752, the chair back 7 and the lifting slide 73 are both moved to the highest point, while the height spring 76 is compressed, the lower end of the height locking part 75 is limited by the cooperation between the unlocking retaining part 733 and the unlocking retaining slot 752, so as to not rotate to approach the vertical hole wall of the lifting guide hole 721; the chair back 7, the lifting slide 73 and the height locking part 75 can all be synchronously moved downward, until the linkage convex part 753 abuts on the second limiting part 724, the height locking part 75 is limited to continuously move downward, at this time, the chair back 7 and the lifting slide 73 continuously move downward, while the height locking part 75 and the height locking shaft 74 remain unchanged, when the unlocking retaining part 733 is separated from the unlocking retaining slot 752, the chair back 7 and the lifting slide 73 are both moved to the lowest point, while the height spring 76 is expanded to drive the lower end of the height locking part 75 to rotate to approach the vertical hole wall of the lifting guide hole 721, so as to facilitate the user to continuously move upward to adjust the height of the chair back 7.

[0042] The preferred embodiments of the present application have been described above with the aid of drawings. It should be understood that the application is not limited to these embodiments.

Claims

1. A training chair with anti-toppling function, comprising a front leg, a rear leg and a seat, the front leg comprising a front seat rod (11) and front chair legs (12) respectively fixed to the left and right ends of the front seat rod (11); the rear leg comprising a rear seat rod (21) and rear chair legs (22) respectively fixed to the left and right ends of the rear seat rod (21), the rear chair legs (22) and the front chair legs (12) being rotationally connected; the seat comprising a seat shell (31), the bottom of the seat shell (31) being provided with a rotating groove (32), and the seat shell (31) further being provided with a bottom shell limiting seat (4) for limiting the rear seat rod (21) in the rotating groove (32); characterized in that: The backrest rod (21) is provided with a folding locking hole (50), the bottom shell limiting seat (4) is provided with a folding locking guide groove (41), the folding locking guide groove (41) is provided with a folding retaining mechanism capable of retaining the chair seat in a folded state, the folding retaining mechanism comprises a folding locking block (51) for inserting into the folding locking hole (50) to limit the chair seat from being turned over and a folding spring (52) for driving the folding locking block (51) to move towards the backrest rod (21) by elasticity, and the folding locking block (51) is configured to rotate around the backrest rod (21) as the chair seat is turned over.

2. The training chair with anti-toppling function according to claim 1, characterized in that: The middle part of the backrest rod (21) is sleeved with a folding locking seat (53), the folding locking seat (53) is provided with a sliding arc surface for sliding contact of the folding locking block (51), and the folding locking hole (50) is formed on the sliding arc surface of the folding locking seat (53).

3. The training chair with anti-toppling function according to claim 2, characterized in that: The folding locking seat (53) is provided with a backrest rod adapting groove matching the external shape of the backrest rod (21), and the folding locking seat (53) and the backrest rod (21) are combined and connected in a bolt connection mode.

4. The training chair with anti-toppling function according to claim 1, characterized in that: The folding locking block (51) comprises a folding locking block (511) and a folding locking insertion part (512) which are integrally connected in sequence, the folding locking insertion part (512) is provided with a hole exit guide inclined surface (513), and the hole exit guide inclined surface (513) is used for pressing the wall surface of the folding locking hole (50) to promote the folding locking insertion part (512) to exit the folding locking hole (50) during unfolding of the chair seat.

5. The training chair with anti-toppling function according to claim 4, characterized in that: The folding locking block (511) is provided with a folding spring groove, one end of the folding spring (52) is inserted into the folding spring groove, and the other end is pressed against the groove wall of the folding locking guide groove (41).

6. A training chair with anti-toppling function according to any one of claims 1-5, characterized in that: The seat shell (31) is further provided with a corresponding seat rod limiting groove (33) communicating with a rotary groove (32), and the bottom shell limiting seat (4) is installed in the seat rod limiting groove (33); the bottom shell limiting seat (4) is provided with a first rotary adapting groove (42), the groove surface of the seat rod limiting groove (33) is provided with a second rotary adapting groove (34) corresponding to the first rotary adapting groove (42), and the first rotary adapting groove (42) and the second rotary adapting groove (34) are combined to form a rotary adapting hole which is rotationally matched with the backrest rod (21).

7. A training chair with anti-toppling function according to any one of claims 1-5, characterized in that: The upper part of the bottom shell limiting seat (4) is provided with an installation limiting plate (54) covering the upper end opening of the folding locking guide groove (41).

8. The training chair with anti-toppling function according to claim 7, characterized in that: The bottom of the installation limiting plate (54) is provided with an upper guide convex rail (541), the groove bottom surface of the folding locking guide groove (41) is provided with a lower guide convex rail (44), the upper part of the folding locking block (51) is provided with an upper guide sliding groove slidingly matched with the upper guide convex rail (541), and the lower part is provided with a lower guide sliding groove slidingly matched with the lower guide convex rail (44).

9. The training chair with anti-toppling function according to any one of claims 1-5, characterized in that: The training chair further comprises a chair back (7), a chair back frame (71) is commonly mounted on the two front chair legs (12), a height lock seat (72) is arranged on the chair back frame (71), a lifting slide seat (73) capable of lifting sliding is guidingly mounted on the height lock seat (72), and the chair back (7) is mounted on the front end of the lifting slide seat (73); a height locking mechanism for limiting the height of the lifting slide seat (73) on the height lock seat (72) is mounted on the lifting slide seat (73).

10. The training chair with anti-toppling function according to claim 9, characterized in that: The height lock seat (72) is provided with a lifting guide hole (721), the lifting slide seat (73) is slidingly fitted in the lifting guide hole (721), a plurality of height clamping grooves (722) arranged from top to bottom are arranged on a vertical hole wall of the lifting guide hole (721), and a hinged long hole (732) is arranged on the lifting slide seat (73); the height locking mechanism comprises a height locking shaft (74), a height locking piece (75) and a height spring (76), both ends of the height locking shaft (74) are fitted and mounted in the two hinged long holes (732) respectively, and the height locking shaft (74) can be lifted and moved along the length direction of the hinged long hole (732); the upper end of the height locking piece (75) is connected to the height locking shaft (74), a height locking portion (751) for being clamped into the height clamping groove (722) to lock the height of the chair back (7) is arranged on one side of the lower end of the height locking piece (75); and the height spring (76) is used for driving the lower end of the height locking piece (75) to rotate towards the height clamping groove (722) with the height locking shaft (74) as the rotation center.

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