Office chair back structure

Abstract

An office chair back structure comprises a chair back frame and a chair seat connecting arm, a chair back lifting groove is formed in the bottom of the chair back frame, a lifting supporting arm is arranged on the chair seat connecting arm, and a lifting locking groove is formed in the lifting supporting arm; a chair back lock seat is fixedly arranged in the chair back lifting groove, and a chair back lock piece is arranged on the chair back lock seat; a hinging long hole and a state limiting groove are formed in the chair back lock seat; the state limiting groove comprises a swinging long hole and an unlocking long hole of which the upper end is communicated with the front end of the swinging long hole; the chair back locking piece is provided with a hinging shaft which can be matched in the hinging long hole in a lifting and rotatable manner, and a state shaft which can move in the state limiting groove. The state shaft is moved to the swing long hole and the unlocking long hole to achieve locking and unlocking of the rotation action of the chair back locking piece, the chair back locking piece is simple and stable, the problems of abrasion and deformation caused by long-term use are effectively avoided, the service life of the lifting function of the chair back is effectively prolonged, the reliability of the lifting function of the chair back is effectively improved, and the use experience of a user is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to office chair technical field, concretely relates to office chair back structure. BACKGROUND

[0002] At present, the chair back of office chair is usually designed as liftable and adjustable to satisfy the use requirement of users of different body types and improve the comfort degree of users of different body types when sitting on the office chair.

[0003] Referring to the technical scheme disclosed in patent application No. 201720709920.X, a chair back lifting mechanism includes a chair back frame, a chair back rod, a pawl, an elastic mechanism and a position adjusting structure. The chair back rod is in vertical sliding cooperation with the chair back frame. The pawl is pivoted to the chair back frame. The chair back rod is provided with a tooth groove extending vertically. Each slot of the tooth groove is inclined upward. The elastic mechanism is installed on the chair back frame and provides an elastic force for the pawl to be buckled into the tooth groove. The position adjusting structure provides a first position for the pawl to be separated from the tooth groove and a second position for the pawl to be buckled into the tooth groove, and drives the pawl to switch between the first position and the second position. This technical scheme can realize position locking between the chair back frame and the chair back rod, realize adjustment of the chair back, and satisfy the use requirement of different users. However, in this technical scheme, the pawl needs to be buckled with the plug on the chair back frame through the insertion hole on the pawl to keep the pawl and the tooth groove in a separated state, so as to facilitate the chair back frame to be lowered to the lowest position for resetting. After the insertion hole and the plug are buckled and separated for many times during use, the insertion hole and the plug are prone to be worn and deformed, resulting in the phenomenon that the plug cannot be effectively buckled in the insertion hole, and the pawl cannot keep the tooth groove in a separated state, which makes the lifting and adjusting function of the chair back invalid. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the utility model provides an office chair back structure.

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

[0006] The utility model provides an office chair back structure, including chair back frame and chair seat connecting arm, the bottom of chair back frame is equipped with chair back lifting groove, is equipped with lifting branch on chair seat connecting arm and is guided in the lifting groove of chair back lifting groove, is equipped with a plurality of lifting lock grooves arranged from top to bottom on the lifting branch, is fixed with chair back lock seat in the chair back lifting groove, is equipped with chair back lock spare on chair back lock seat, its characterized in being: be equipped with articulated long hole and state restriction groove on chair back lock seat, state restriction groove includes swing long hole and the unlocking long hole of upper end communication with swing long hole front end, be equipped with articulated axle that can lift and can rotate and cooperate in articulated long hole on chair back lock spare, and state axle can be active in state restriction groove, be equipped with the upper lock switch part of the state axle in swing long hole with chair back lock spare cooperation when making when the lifting branch is equipped with the unlocking switch part of the state axle in unlocking long hole with chair back lock spare cooperation when making when the chair back frame drops to the lowest point,

[0007] Chair back lock spare is configured to be non-rotatable when state axle is in unlocking long hole and is kept separate from lifting lock groove, and locking spring is installed on chair seat lock seat to drive chair back lock spare rear end to rotate by elastic force when state axle is in swing long hole to cooperate with lifting lock groove.

[0008] In the utility model, the chair back lock seat includes a lock seat main body fixedly connected with the chair back frame and two integrally formed chair back lock portions provided on the lock seat main body, the chair back lock portion and the locking spring are located between the two chair back lock portions, the articulated long hole, the swing long hole and the unlocking long hole are provided on each of the chair back lock portions, the two ends of the articulated axle are respectively fitted into the articulated long holes on the two chair back lock portions, and the two ends of the state axle are respectively fitted into the state restriction grooves on the two chair back lock portions.

[0009] In the utility model, the front side of the chair back frame is provided with a lock seat mounting groove, the rear side wall of the lock seat mounting groove is provided with a lock seat mounting opening communicating with the chair back lifting groove, the lock seat main body is mounted in the lock seat mounting groove, and the two chair back lock portions extend into the chair back lifting groove through the lock seat mounting opening.

[0010] In the utility model, the front side of the lifting branch is recessed rearward to form a lifting avoiding cavity, the lifting lock groove, the upper lock switch portion and the unlocking switch portion are located in the lifting avoiding cavity, and the chair back lock portion extends into the lifting avoiding cavity.

[0011] In the utility model, the left and right sides of the lifting branch are both provided with bracket guide members, the two ends of each bracket guide member extend to the front side and the rear side of the lifting branch, the bracket guide member is provided with a lifting vertical guide groove, the groove wall of the chair back lifting groove is provided with a chair back lifting vertical rib, and the lifting vertical guide groove of each bracket guide member at least slidingly guides one chair back lifting vertical rib.

[0012] In the utility model, the positioning installation groove for limiting the up-down movement of the support guide piece is arranged on the lifting support arm, one support guide piece is positioned and installed in each positioning installation groove, the inner side of the support guide piece is embedded into the positioning installation groove to realize positioning, and the outer side protrudes out of the positioning installation groove and is provided with the lifting vertical guide groove.

[0013] In the utility model, the chair back lock piece comprises a lock piece main body and a lock piece lock portion protruding at the lower end of the rear side of the lock piece main body, the lock piece main body is provided with a first shaft hole and a second shaft hole distributed from top to bottom, the middle part of the hinge shaft is inserted into the first shaft hole, and the middle part of the state shaft is inserted into the second shaft hole.

[0014] In the utility model, the upper locking switching portion is located at the lower part of the lifting avoiding cavity, and the lower end of the lock piece main body is provided with a lock piece upper locking cooperation portion for cooperating with the upper locking switching portion to link the up-moving and rotary resetting of the chair back lock piece relative to the chair back lock seat.

[0015] In the utility model, the unlocking switching portion is located at the upper part of the lifting avoiding cavity, the unlocking switching portion comprises an unlocking limiting surface for blocking the up-moving of the lock piece main body and an unlocking guide surface for enabling the lower end of the lock piece main body to rotate and swing forward around the hinge shaft as the center, and the upper end of the unlocking guide surface is inclined forward and upward.

[0016] In the utility model, the inner wall of the lifting avoiding cavity is protrusively provided with a lifting protruding rib, and the rear end of the chair back lock portion protrusively has a sliding protruding portion slidingly abutting on the front end of the lifting protruding rib.

[0017] The utility model discloses the beneficial effects: the utility model discloses the state shaft is moved to swing long hole and unlocking long hole to realize the locking and unlocking of the rotary action of chair back lock piece, compared with the traditional jack and the plug buckle type structure, its structure is simpler and more stable, effectively avoids the abrasion and deformation problem caused by long -term use, makes the service life and reliability of chair back lifting function effectively improve, thereby improving the user's use experience. BRIEF DESCRIPTION OF DRAWINGS

[0018] The utility model is further illustrated in connection with the drawings and implementation:

[0019] Figure 1 It is the perspective view of office chair chair back structure;

[0020] Figure 2 It is the cooperation schematic view between chair back lock seat and chair back lock piece;

[0021] Figure 3 It is Figure 2 It is the enlarged view of middle A portion;

[0022] Figure 4 It is the perspective view of chair seat connecting arm;

[0023] Figure 5 is a combined perspective view of the chair back lock seat and the chair back lock piece;

[0024] Figure 6 is a perspective view of the office chair back structure without the lumbar support device;

[0025] Figure 7 is a perspective view of the lumbar support device;

[0026] Figure 8 is a position schematic view of the self-adaptive pulley assembly. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0028] Referring to Figures 1-8 An office chair back structure comprises a chair back frame 1 and a seat connecting arm 2, the top of the chair back frame 1 is provided with a headrest device, the seat connecting arm 2 is used for connecting the seat of the office chair, the bottom of the chair back frame 1 is provided with a chair back lifting groove 11, the seat connecting arm 2 is provided with a lifting supporting arm 21 which is guided and matched in the chair back lifting groove 11, and the lifting supporting arm 21 is provided with a plurality of lifting lock grooves 22 arranged from top to bottom; the chair back lifting groove 11 is fixedly provided with a chair back lock seat 3, and the chair back lock seat 3 is provided with a chair back lock piece 4 used for locking the height of the chair back frame 1 in cooperation with the lifting lock grooves 22.

[0029] Further, the chair back lock seat 3 is provided with a hinged long hole 31 and a state limiting groove, the state limiting groove comprises a swing long hole 32 and an unlocking long hole 33 which is communicated with the front end of the swing long hole 32 at the upper end, the hinged long hole 31 and the unlocking long hole 33 are both long circular holes, and the length direction of the hinged long hole 31 and the length direction of the unlocking long hole 33 are both parallel or substantially parallel to the direction of the lifting movement of the chair back frame 1.

[0030] Still further, the chair back lock piece 4 is provided with a hinged shaft 5 which is lifted and rotated and matched in the hinged long hole 31, and a state shaft 6 which can move in the state limiting groove; the lifting supporting arm 21 is provided with an upper locking switching part 23 which can cooperate with the chair back lock piece 4 to make the state shaft 6 slide into the swing long hole 32 when the chair back frame 1 is lifted to the highest point, and an unlocking switching part 24 which can cooperate with the chair back lock piece 4 to make the state shaft 6 slide into the unlocking long hole 33 when the chair back frame 1 is lowered to the lowest point.

[0031] Further, the chair back lock 4 is configured to be non-rotatable and separated from the lifting lock slot 22 when the state shaft 6 is in the unlocking long hole 33; the chair back lock seat is provided with a locking spring 7 for driving the lower end of the chair back lock 4 to rotate backward by elastic force when the state shaft 6 is in the swing long hole 32, so as to limit the height of the chair back frame 1 in cooperation with the lifting lock slot 22.

[0032] The utility model discloses a state shaft 6 is moved to swing long hole 32 and unlocking long hole 33 to realize the locking and unlocking of the rotating action of chair back lock 4, compared with the traditional jack and plug buckle type structure, its structure is simpler and stable, effectively avoid the abrasion and deformation problem caused by long -term use, make the service life and reliability of chair back lifting function effectively improve, thereby improve the user's use experience.

[0033] As a preferred embodiment, the chair back lock seat 3 includes a lock seat body 34 fixedly connected with the chair back frame 1 and two integrally formed chair back lock portions 35 provided on the lock seat body 34, the chair back lock 4 and the locking spring 7 are located between the two chair back lock portions 35, the chair back lock portion 35 is provided with the articulated long hole 31, the swing long hole 32 and the unlocking long hole 33, the two ends of the articulated shaft 5 are respectively matched in the articulated long hole 31 on the two chair back lock portions 35, and the two ends of the state shaft 6 are respectively matched in the state limiting slot on the two chair back lock portions 35.

[0034] As a preferred embodiment, the front side of the chair back frame 1 is provided with a lock seat mounting slot 13, the rear side wall of the lock seat mounting slot 13 is provided with a lock seat mounting opening communicating with the chair back lifting groove 11, the lock seat body 34 is mounted in the lock seat mounting slot 13, and the two chair back lock portions 35 extend into the chair back lifting groove 11 through the lock seat mounting opening.

[0035] As a preferred embodiment, the front side of the lifting support arm 21 is recessed backward to form a lifting avoiding cavity 25, the lifting lock slot 22, the locking switching portion 23 and the unlocking switching portion 24 are located in the lifting avoiding cavity 25, and the chair back lock portion 35 extends into the lifting avoiding cavity 25.

[0036] As a preferred embodiment, the left and right sides of the lifting support arm 21 are provided with support guide pieces 8, the two ends of the support guide piece 8 extend to the front side and the rear side of the lifting support arm 21 respectively, the support guide piece 8 is provided with a lifting vertical guide slot 81, the groove wall of the chair back lifting groove 11 is provided with a chair back lifting vertical rib in protrusion, the lifting vertical guide slot 81 of each support guide piece 8 is at least slidingly guided and matched with one chair back lifting vertical rib, so that the lifting support arm 21 is guided and matched in the chair back lifting groove 11.

[0037] In the embodiment, the lifting support arm 21 is provided with positioning installation grooves for limiting the up-and-down movement of the support guide 8. Each positioning installation groove is positioned and installed with one support guide 8. The inner side of the support guide 8 is embedded into the positioning installation groove to achieve positioning, and the outer side protrudes out of the positioning installation groove and is provided with the lifting vertical guide groove 81. The positioning installation groove positions the support guide 8, thereby ensuring the stability of the use of the support guide 8.

[0038] As a preferred embodiment, the chair back lock 4 comprises a lock body 41 and a lock portion 42 protruding at the lower end of the rear side of the lock body 41. The lock body 41 is provided with a first shaft hole and a second shaft hole distributed from top to bottom. The middle part of the hinge shaft 5 is inserted into the first shaft hole, and the middle part of the state shaft 6 is inserted into the second shaft hole. The lock portion 42 is used to cooperate with the lifting lock groove 22 and the unlocking switching portion 24.

[0039] In the embodiment, the cross-sectional shape of the lifting lock groove 22 is “∠” type. The lifting lock groove 22 is composed of a lifting support surface 221 and a groove guide inclined surface 222 extending upward and forward from the rear end of the lifting support surface 221. When the lock portion 42 abuts against the lifting support surface 221, the chair back frame 1 cannot be lowered. The groove guide inclined surface 222 is used to control the lock portion 42 to disengage from the currently cooperating lifting lock groove 22, so as to cooperate with the next gear lifting lock groove 22.

[0040] In the embodiment, the locking switching portion 23 is located at the lower part of the lifting avoiding cavity 25. The lower end of the lock body 41 is provided with a lock portion 43 for cooperating with the locking switching portion 23 to link the chair back lock 4 to move upward and rotate to reset relative to the chair back lock seat 3. During the process of lowering and resetting the chair back frame 1, the lock portion 43 first abuts against the top of the locking switching portion 23, and then moves upward with the chair back lock 4 relative to the chair back lock seat 3 as the chair back frame 1 continues to move downward. Then, the hinge shaft 5 moves to the upper part of the hinge long hole 31 and the state shaft 6 moves to the front end of the swing long hole 32 as the chair back frame 1 continues to move downward until the chair back lock portion 35 abuts against the bottom surface of the lifting avoiding cavity 25. At this time, the lower end of the chair back lock 4 rotates backward and swings to reset with the hinge shaft 5 as the center under the elastic force of the locking spring 7, so that the lock portion 42 can cooperate with the lifting lock groove 22 to lock the height of the chair back frame 1.

[0041] In this embodiment, the unlocking switching part 24 is located above the lifting and avoiding cavity 25. The unlocking switching part 24 includes an unlocking limiting surface 241 for preventing the locking body 41 from moving upward and an unlocking guiding surface 242 for causing the lower end of the locking body 41 to rotate forward about the hinge axis 5. The upper end of the unlocking guiding surface 242 is inclined forward and upward. After the chair back lock 4 rises past the highest lifting lock groove 22, the locking part 42 slides on the unlocking guiding surface 242. At this time, the lower end of the chair back lock 4 rotates forward about the hinge axis 5 under the action of the unlocking guiding surface 242, so that the locking part 42 engages with the highest lifting lock groove 22. The groove 22 separates, and the locking spring 7 contracts to store energy. When the top of the chair back lock 4 presses against the unlocking limit surface 241, as the chair back frame 1 continues to move upward, the chair back lock seat 3 moves upward relative to the chair back lock 4, causing the hinge shaft 5 to slide into the lower end of the hinge elongated hole 31 and the state shaft 6 to slide into the lower end of the unlocking elongated hole 33. At the same time, under the elastic force of the locking spring 7, the hinge shaft 5 presses against the lower end hole wall of the hinge elongated hole 31 and the state shaft 6 presses against the lower end hole wall of the unlocking elongated hole 33. Thus, the chair back lock 4 cannot move arbitrarily relative to the chair back lock seat 3 during the process of the chair back frame 1 moving downward and resetting, thereby keeping the chair back lock 4 in a state separated from the lifting lock groove 22.

[0042] In this embodiment, the lock body 41 is provided with a first spring groove, the lock seat body 34 is provided with a second spring groove, the locking spring 7 is a compression spring, and the two ends of the locking spring 7 are respectively inserted into the first spring groove and the second spring groove, thereby realizing the installation of the locking spring 7 and making the locking spring 7 less likely to shift.

[0043] In this embodiment, the inner wall of the lifting and avoiding cavity 25 is provided with a lifting rib 251, and the rear end of the chair back lock part 35 is provided with a sliding protrusion 351 that slides against the front end of the lifting rib 251, so that the lifting arm 21 can slide more smoothly in the chair back lifting groove 11.

[0044] In a preferred embodiment, a lumbar support device 10 is also included. The lumbar support device 10 includes an adaptive base 101 mounted on the front side of the chair back frame 1, an adaptive slide 102 slidably mounted on the adaptive base 101 and capable of being raised and lowered relative to the adaptive base 101, a lumbar support seat 103 on the adaptive slide 102, and a lumbar support frame 104 mounted on the lumbar support seat 103. The lumbar support frame 104 is used to install a mesh fabric. Furthermore, the adaptive slide 102 is configured to slide forward and downward when the user leans against the lumbar support device 10; the adaptive base 101 is provided with an adaptive inner groove 1011, and the outer side of the adaptive base 101 is provided with an adaptive groove 1012 communicating with the adaptive inner groove 1011; the adaptive slide 102 is provided with an adaptive extension 1021 extending from the adaptive groove 1012 into the adaptive inner groove 1011; the adaptive inner groove 1011 is provided with an adaptive tension spring 105, one end of the adaptive tension spring 105 is connected to the adaptive base 101, and the other end is connected to the adaptive extension 1021; the adaptive tension spring 105 is configured to drive the adaptive slide 102 to slide backward and upward to reset through elastic force, thereby allowing the adaptive tension spring 105 to provide a certain support force to support the user's waist.

[0045] In a preferred embodiment, the adaptive base 101 is provided with an adaptive sliding guide surface 1013 for guiding the adaptive slide block 102 to slide. There are two adaptive slide grooves 1012 on the adaptive sliding guide surface 1013, arranged from left to right. The number of adaptive extensions 1021 matches the number of adaptive slide grooves 1012. Each adaptive slide groove 1012 passes through one of the adaptive extensions 1021 so that the adaptive extensions 1021 can extend into the adaptive inner groove 1011.

[0046] In this embodiment, for ease of installation, the lower ends of both the adaptive inner groove 1011 and the adaptive slide 1012 extend downwards through the bottom of the adaptive base 101. An adaptive cover 106 is installed on the adaptive base 101 to close the lower ends of the adaptive inner groove 1011 and the adaptive slide 1012. The adaptive cover 106 is installed on the adaptive base 101 by bolt connection. During installation, the adaptive extension 1021 first enters the adaptive inner groove 1011 and the adaptive slide 1012 from the opening position at the lower end of the adaptive inner groove 1011 and the adaptive slide 1012. Then, the adaptive cover 106 closes the opening position at the lower end of the adaptive inner groove 1011 and the adaptive slide 1012, thereby preventing the adaptive extension 1021 from slipping off.

[0047] In this embodiment, the two adaptive extensions 1021 are jointly mounted on an adaptive mounting rod 107. One end of the adaptive tension spring 105 is fixed to the adaptive base 101 by bolt connection, and the other end is connected to the adaptive mounting rod 107, thereby completing the installation of the adaptive tension spring 105.

[0048] In this embodiment, the adaptive extension 1021 is provided with an adaptive guide 1022 at one end of the adaptive inner groove 1011 to limit the adaptive extension 1021 from moving forward out of the adaptive slide groove 1012. The groove surface of the adaptive inner groove 1011 has an adaptive guide protrusion that can slide in contact with the adaptive guide 1022, thereby preventing the adaptive guide 1022 from directly sliding in contact with the groove surface of the adaptive inner groove 1011, reducing sliding friction and improving the smoothness of the adaptive function.

[0049] In this embodiment, the adaptive inner groove 1011 is equipped with an adaptive buffer block 108 for blocking the adaptive slide 102 when it moves backward and upward to the end point. Each adaptive buffer block 108 corresponds to an adaptive extension 1021.

[0050] In this embodiment, the adaptive slide 102 is provided with at least two adaptive pulley assemblies 109 that slide on the adaptive sliding guide surface 1013. The adaptive pulley assemblies 109 can reduce the friction when the adaptive slide 102 slides relative to the adaptive base 101.

[0051] The above description is only a preferred embodiment of the present utility model. Any technical solution that achieves the purpose of the present utility model by essentially the same means shall fall within the protection scope of the present utility model.

Claims

1. An office chair back structure, comprising a backrest frame (1) and a seat connecting arm (2), wherein the bottom of the backrest frame (1) is provided with a backrest lifting groove (11), and the seat connecting arm (2) is provided with a lifting support arm (21) that is guided and engaged in the backrest lifting groove (11), and the lifting support arm (21) is provided with a plurality of lifting locking grooves (22) arranged from top to bottom; a backrest lock seat (3) is fixedly installed in the backrest lifting groove (11), and a backrest lock component (4) is provided on the backrest lock seat (3); characterized in that: The chair back lock seat (3) is provided with a hinged elongated hole (31) and a state limiting groove. The state limiting groove includes a swing elongated hole (32) and an unlocking elongated hole (33) whose upper end is connected to the front end of the swing elongated hole (32). The chair back lock (4) is provided with a hinge shaft (5) that can be raised and lowered and rotated in the hinged elongated hole (31) and a state shaft (6) that can move in the state limiting groove. The lifting support arm (21) is provided with a locking switching part (23) that can cooperate with the chair back lock (4) to make the state shaft (6) slide into the swing elongated hole (32) when the chair back frame (1) rises to the highest point and an unlocking switching part (24) that can cooperate with the chair back lock (4) to make the state shaft (6) slide into the unlocking elongated hole (33) when the chair back frame (1) falls to the lowest point. The chair back lock (4) is configured to be non-rotatable and separate from the lifting lock groove (22) when the state shaft (6) is in the unlocking elongated hole (33); the chair seat lock is equipped with a locking spring (7) that uses elastic force to drive the lower end of the chair back lock (4) to rotate backward when the state shaft (6) is in the swing elongated hole (32) to cooperate with the lifting lock groove (22).

2. The office chair back structure according to claim 1, characterized in that: The chair back lock seat (3) includes a lock seat body (34) fixedly connected to the chair back frame (1) and two integrally formed chair back lock parts (35) provided on the lock seat body (34). The chair back lock (4) and the locking spring (7) are both located between the two chair back lock parts (35). The chair back lock parts (35) are provided with the hinge elongated hole (31), the swing elongated hole (32) and the unlocking elongated hole (33). The two ends of the hinge shaft (5) are respectively fitted into the hinge elongated holes (31) on the two chair back lock parts (35). The two ends of the state shaft (6) are respectively fitted into the state limiting grooves on the two chair back lock parts (35).

3. The office chair back structure according to claim 2, characterized in that: The front side of the chair back frame (1) is provided with a lock seat mounting groove (13), and the rear side wall of the lock seat mounting groove (13) is provided with a lock seat mounting port that connects to the chair back lifting groove (11). The lock seat body (34) is installed in the lock seat mounting groove (13), and the two chair back lock parts (35) extend into the chair back lifting groove (11) through the lock seat mounting port.

4. The office chair back structure according to claim 3, characterized in that: The front side of the lifting arm (21) is recessed to the rear to provide a lifting clearance cavity (25). The lifting lock groove (22), the locking switch part (23) and the unlocking switch part (24) are all located in the lifting clearance cavity (25). The chair back lock part (35) extends into the lifting clearance cavity (25).

5. The office chair back structure according to claim 1, characterized in that: The lifting arm (21) is provided with bracket guides (8) on both the left and right sides. The two ends of the bracket guides (8) extend to the front and rear sides of the lifting arm (21) respectively. The bracket guides (8) are provided with lifting vertical guide grooves (81). The backrest lifting groove (11) is provided with a backrest lifting vertical rib. Each bracket guide (8) has a lifting vertical guide groove (81) that slides and guides at least one backrest lifting vertical rib.

6. The office chair back structure according to claim 5, characterized in that: The lifting arm (21) is provided with a positioning mounting groove for limiting the up and down movement of the bracket guide (8). Each positioning mounting groove is equipped with a bracket guide (8). The inner side of the bracket guide (8) is embedded in the positioning mounting groove to achieve positioning, and the outer side protrudes out of the positioning mounting groove and is provided with the lifting vertical guide groove (81).

7. The office chair back structure according to any one of claims 1-6, characterized in that: The chair back lock (4) includes a lock body (41) and a lock part (42) protruding from the lower rear side of the lock body (41). The lock body (41) is provided with a first shaft hole and a second shaft hole distributed from top to bottom. The middle part of the hinge shaft (5) is inserted into the first shaft hole, and the middle part of the state shaft (6) is inserted into the second shaft hole.

8. The office chair back structure according to claim 7, characterized in that: The locking switching part (23) is located at the lower part of the lifting and avoiding cavity (25). The lower end of the locking body (41) is provided with a locking engagement part (43) for cooperating with the locking switching part (23) to move the backrest lock (4) relative to the backrest lock seat (3) upward and rotate to reset.

9. The office chair back structure according to claim 7, characterized in that: The unlocking switching part (24) is located on the upper part of the lifting and avoiding cavity (25). The unlocking switching part (24) includes an unlocking limiting surface (241) for blocking the upward movement of the lock body (41) and an unlocking guide surface (242) for causing the lower end of the lock body (41) to rotate forward about the hinge axis (5). The upper end of the unlocking guide surface (242) is inclined forward and upward.

10. The office chair back structure according to claim 4, characterized in that: The inner wall of the lifting and avoiding cavity (25) is provided with a lifting rib (251), and the rear end of the chair back lock (35) is provided with a sliding protrusion (351) that slides against the front end of the lifting rib (251).

Images