Chair back structure capable of enabling user to obtain dynamic support when different sitting postures are switched

Abstract

According to the chair back structure capable of enabling a user to obtain dynamic support when the user switches different sitting postures, the horizontal movement mechanism and the elastic lifting mechanism are arranged to control the horizontal movement and the vertical movement of the second chair back, and the horizontal movement and the vertical movement can be simultaneously carried out; the horizontal movement mechanism and the elastic lifting mechanism enable the second chair back to move along with movement of the waist of the user through elastic force given by a spring, the second chair back can be tightly attached to and support the waist of the user no matter what posture of the user is, dynamic support is formed, comfortable use experience is brought to the user, and the situation that the user sits for a long time is relieved. And discomfort such as waist fatigue can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of seats, and in particular to a chair back structure which enables a user to obtain dynamic support when switching between different sitting postures. Background Art

[0002] With the rapid development of the economy, people are also under high pressure at work. For office workers, they often need to sit at their desks for a long time to work. Sitting for a long time will inevitably bring a series of diseases. Among them, if the waist cannot be supported and moved for a long time, it will lead to lumbar disc herniation, blood circulation problems, etc., which are extremely harmful. Therefore, it is necessary to set a suitable structure for the waist position to relieve the pressure on the waist.

[0003] At present, most of the chairs on the market have a lumbar support installed on the back of the chair with slightly adjustable height and reclining angle. The lumbar support provides certain support conditions for the waist, but its function is relatively simple and it requires maintaining a fixed sitting posture and position to provide support. The lumbar support can only move within a certain angle range. Once the user leaves the use angle, the waist will be out of the support of the lumbar support. Therefore, its support effect and comfort need to be improved. Utility Model Content

[0004] In view of the shortcomings of the above-mentioned technology that the lumbar support follows the waist movement and cannot provide good comfort, the utility model provides a chair back structure that allows the user to obtain dynamic support when switching between different sitting postures.

[0005] To achieve the above-mentioned purpose, the utility model provides a chair back structure that allows a user to obtain dynamic support when switching between different sitting postures, comprising:

[0006] First chair back.

[0007] A chair back bracket, wherein the first chair back is fixedly connected to one end of the chair back bracket, and the other end of the chair back bracket is movably connected to the seat.

[0008] A horizontal movement mechanism, wherein the chair back support is sleeved on one end of the horizontal movement mechanism, an elastic lifting mechanism is provided at the other end of the horizontal movement mechanism, one end of the elastic lifting mechanism is fixedly connected to the horizontal movement mechanism, and a second chair back is provided at the other end of the elastic lifting mechanism, and the second chair back is movably connected to the elastic lifting mechanism;

[0009] The second chair back performs composite motion in front-back and up-down directions simultaneously through the horizontal motion mechanism and the elastic lifting mechanism.

[0010] As an improved solution of the utility model, the horizontal movement mechanism includes a sliding cylinder with an opening at one end, a first spring and an adjusting knob; the chair back bracket is provided with a fixed cylinder with openings at both ends, and the chair back bracket is sleeved on the fixed cylinder; the adjusting knob is movably connected to one end of the fixed cylinder; the end face of the adjusting knob is provided with a positioning column, and the positioning column is sleeved on the first spring, the sliding cylinder and the fixed cylinder in sequence; the sliding cylinder is slidably matched with the fixed cylinder, and one end of the sliding cylinder close to the elastic lifting mechanism is fixedly connected to the elastic lifting mechanism; one end of the first spring is fixed to the end face of the adjusting knob, and the other end abuts against the inner end face of the sliding cylinder.

[0011] As an improved scheme of the utility model, the elastic lifting mechanism includes a sliding bracket, a sliding member and at least one second spring, the second seat back is provided with a first sink groove, and the sliding bracket is fixedly arranged in the first sink groove; the sliding member is sleeved on the sliding bracket, and the sliding bracket is provided with at least two first slide grooves on a surface close to the second seat back, and the second spring is arranged in the first slide groove, and the sliding member is provided with at least two protrusions, one of the protrusions extends into one of the first slide grooves correspondingly, and one of the protrusions abuts against one of the second springs correspondingly; a connecting block is provided on the other surface of the sliding bracket, and a threaded connecting hole is provided on the connecting block, and an installation port is provided at one end of the sliding cylinder away from the adjusting knob, the connecting block is sleeved in the installation port, and a connecting hole is provided on the wall surface of the sliding cylinder, and an external bolt passes through the connecting hole and the threaded connecting hole to fix the sliding bracket with the sliding cylinder.

[0012] As an improved solution of the utility model, at least one limit groove is provided on one side of the sliding member, a first slot hole is provided on the slot wall of the first sinking groove opposite to the limit groove, a limit adjustment rod and a fixing member are provided on the second chair back, the fixing member is fixedly arranged in the first slot hole, the limit adjustment rod is sleeved in the cavity of the fixing member, the limit adjustment rod is movably connected to the fixing member, and one end of the limit adjustment rod is interlocked with the limit groove through the first slot hole.

[0013] As an improved scheme of the utility model, at least one limiting through hole is provided on the wall surface of the sliding cylinder, and the outer wall surface of the fixed cylinder forms a first connecting cylinder with an open end, and the first connecting cylinder has an open end with a limiting knob sleeved thereon, and the limiting knob is movably connected to the first connecting cylinder, and a first through hole is provided on the wall surface where the first connecting cylinder and the sliding cylinder are connected, the limiting knob is fixedly connected to one end of the limiting column, and the other end of the limiting column is mutually engaged with the limiting through hole through the first through hole.

[0014] As an improved solution of the utility model, at least one sliding wheel is symmetrically provided on the outer wall surface of the sliding cylinder, and the sliding wheel is fixedly connected to the sliding cylinder; at least one guide column is provided on the inner wall surface of the fixed cylinder, and the guide column and the fixed cylinder are integrally formed, and a guide groove is provided on the guide column, and two guide columns have one side with the guide groove arranged opposite to each other, and at least one sliding wheel is embedded between the two guide grooves.

[0015] As an improved solution of the utility model, a first connecting column with openings at both ends is provided in the first connecting tube, and two external threads facing each other are symmetrically provided on the outer wall surface of the first connecting column. The end surface where the limit knob is connected to the limit column is also provided with a second connecting tube with an opening at one end, and at least two second connecting columns are symmetrically provided on the inner wall of the second connecting tube, and the two second connecting columns clamp the first connecting column, and the second connecting column fits the external thread.

[0016] The beneficial effect of the utility model is as follows: compared with the prior art, the utility model provides a chair back structure that allows the user to obtain dynamic support when switching between different sitting postures. The horizontal movement mechanism and the elastic lifting mechanism are arranged to control the horizontal movement and vertical movement of the second chair back, and horizontal and vertical compound movements can be performed simultaneously. The elastic force given by the horizontal movement mechanism and the elastic lifting mechanism through the spring enables the second chair back to move with the user's waist movement. No matter what posture the user is in, the second chair back can be ensured to closely support the user's waist, and dynamic support can be formed when the user's waist moves. The lumbar support has extremely high freedom of movement, which brings a comfortable use experience to the user and alleviates the problems of waist fatigue and other discomfort caused by sitting for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a left view of the utility model;

[0018] Figure 2 This is an exploded view of the horizontal motion mechanism of the utility model;

[0019] Figure 3 This is a bottom view of the sliding cylinder of the utility model;

[0020] Figure 4 This is a schematic diagram of the first sink of the utility model;

[0021] Figure 5 This is a rear view of the second chair of the present invention;

[0022] Figure 6 It is a schematic diagram of a fixed cylinder of the utility model;

[0023] Figure 7 This is an exploded view of the elastic lifting mechanism of the utility model;

[0024] Figure 8 It is a schematic diagram of a sliding bracket of the utility model;

[0025] Fig. 9 It is a three-dimensional diagram of the utility model;

[0026] Fig.10 It is a cross-sectional view of the utility model;

[0027] Fig.11 It is a schematic diagram of the sliding cylinder and the sliding bracket of the utility model;

[0028] Fig.12 It is a schematic diagram of the limit knob and the first connecting tube of the utility model;

[0029] Fig.13 This is a schematic diagram of the first connecting tube of the utility model;

[0030] Fig.14 This is a cross-sectional view of the first connecting tube of the utility model.

[0031] The main component symbols are described as follows:

[0032] 1. First chair back; 2. Second chair back; 21. First sink groove; 3. Chair back bracket; 31. Fixed cylinder; 311. Guide column; 312. Guide groove; 4. Horizontal movement mechanism; 41. Sliding cylinder; 411. Limiting through hole; 42. First spring; 43. Adjusting knob; 44. Positioning column; 45. Sliding wheel; 5. Elastic lifting mechanism; 51. Sliding bracket; 511. First slide groove; 512. Connecting block; 52. Sliding member; 521. Protrusion; 522. Limiting groove; 53. Second spring; 6. First connecting cylinder; 61. First connecting column; 611. External thread; 612. Slot; 7. Limiting knob; 71. Limiting column; 72. Second connecting cylinder; 73. Second connecting column; 8. Connecting hole; 9. Threaded connecting hole. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with the accompanying drawings.

[0034] In the following description, the example details are given to provide a deeper understanding of the utility model. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. It should be understood that the specific embodiments are only used to explain the utility model, and are not used to limit the utility model.

[0035] It should be understood that when the terms "include" and / or "comprises" are used in this specification, they indicate the existence of the stated features, integers, steps, operations, elements or components, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, components or combinations thereof.

[0036] See also Figure 1-Figure 14 The utility model provides a chair back structure that allows a user to obtain dynamic support when switching between different sitting postures, including:

[0037] First chair back 1.

[0038] The first chair back 1 is fixedly connected to one end of the chair back support 3, and the other end of the chair back support 3 is movably connected to the seat.

[0039] A horizontal motion mechanism 4, a backrest bracket 3 is sleeved on one end of the horizontal motion mechanism 4, an elastic lifting mechanism 5 is provided at the other end of the horizontal motion mechanism 4, one end of the elastic lifting mechanism 5 is fixedly connected to the horizontal motion mechanism 4, and the other end is provided with a second backrest 2, and the second backrest 2 is movably connected to the elastic lifting mechanism 5;

[0040] The second chair back 2 performs composite motion in the front-back direction and in the up-down direction simultaneously through the horizontal motion mechanism 4 and the elastic lifting mechanism 5 .

[0041] The first chair back 1 is arranged above the second chair back 2, and fits the user's back and waist respectively. The second chair back 2 is connected with the elastic lifting mechanism 5 and the horizontal movement mechanism 4 in sequence. The up and down height and the front and back position of the second chair back 2 can be adjusted by the elastic lifting mechanism 5 and the horizontal movement mechanism 4, and the vertical and horizontal compound movements can be performed simultaneously, so that the position of the user's waist and the second chair back 2 remains dynamic and unchanged. The user controls the position of the second chair back 2 through the friction resistance between the waist and the second chair back 2, so that the user can obtain the support of the waist by the second chair back 2 in different sitting postures, which effectively alleviates the symptoms or fatigue of the user caused by the waist not being supported for a long time when sitting for a long time, and brings excellent comfort to the user.

[0042] The working principle of the utility model is:

[0043] The second chair back 2 is movably connected with the elastic lifting mechanism 5. When the user's waist leans on the second chair back 2, the sliding member 52 in the elastic lifting mechanism 5 that slidably cooperates with the sliding bracket will move with the movement of the user, and the second spring 53 is arranged in the first sliding groove 511 of the sliding bracket, and the protrusion 521 on the sliding member 52 abuts against the second spring 53. When the user leans back or presses down the second chair back 2, the protrusion 521 squeezes the second spring 53, and the second spring 53 generates an elastic force after being squeezed. When the user leaves the second chair back 2, the elastic force restores the second chair back 2 to its original height position. In the horizontal movement mechanism 4, the horizontal sliding of the second chair back 2 is achieved through the cooperation of the sliding wheel 45 on the sliding cylinder 41 and the guide groove 312 on the fixed cylinder 31, and the first spring 42 sleeved on the positioning column 44 in the sliding cylinder 41 is fixedly connected with the adjusting knob 43. When the sliding cylinder 41 slides, the sliding cylinder 41 squeezes the first spring 42. Similarly, the first spring 42 The second chair back 2 is reset to the horizontal starting position. The second chair back 2 can move along with the user's waist through the first spring 42 and the second spring 53, and can perform reset movements in the horizontal and vertical directions at the same time, with a very high degree of freedom. Since the first spring 42 is also fixedly connected to the adjusting knob 43, the tightness of the first spring 42 can be adjusted by rotating the adjusting knob 43, and the magnitude of the rebound force and the supporting force of the second chair back 2 can be indirectly adjusted. In addition, the elastic lifting mechanism 5 and the horizontal movement mechanism 4 are both provided with lockable structures, such as the limit knob on the horizontal movement mechanism 4 and the limit through hole 411 on the sliding cylinder 41. When the user wants to keep it fixed in a suitable position, the horizontal position of the second chair back 2 can be fixed by plugging and unplugging the limit knob. Similarly, the limit adjustment rod provided on the second chair back 2 is engaged with the limit groove 522 on the sliding member 52, and the second chair back 2 at different heights can be fixed by adjusting the limit adjustment rod to engage in the limit grooves 522 at different positions.

[0044] In another embodiment, all the technical features of the above embodiments are included, the horizontal movement mechanism 4 includes a sliding cylinder 41 with an opening at one end, a first spring 42 and an adjusting knob 43, the backrest bracket 3 is provided with a fixed cylinder 31 with openings at both ends, and the backrest bracket 3 is sleeved on the fixed cylinder 31; the adjusting knob 43 is movably connected to one end of the fixed cylinder 31; the end surface of the adjusting knob 43 is provided with a positioning column 44, and the positioning column 44 is sleeved with the first spring 42, the sliding cylinder 41 and the fixed cylinder 31 in sequence; the sliding cylinder 41 is slidably matched with the fixed cylinder 31, and the end of the sliding cylinder 41 close to the elastic lifting mechanism 5 is fixedly connected to the elastic lifting mechanism 5 One end of the first spring 42 is fixed to the end face of the adjusting knob 43, and the other end abuts against the elastic lifting mechanism 5. The second chair back 2 moves in the horizontal direction through the sliding cooperation between the sliding cylinder 41 and the fixed cylinder 31, and the first spring 42 in the sliding cylinder 41 is respectively connected to the elastic lifting mechanism 5 and the adjusting knob 43. When the second chair back 2 moves horizontally, the first spring 42 is squeezed and relaxed with the movement of the second chair back 2. The first spring 42 can also be tightened and relaxed by rotating the adjusting knob 43 to control the tension force of the first spring 42, thereby controlling the elastic supporting force of the horizontal movement mechanism 4 on the second chair back 2.

[0045] Furthermore, it also includes an elastic lifting mechanism 5 for controlling the height of the second chair back 2, including a sliding bracket 51, a sliding member 52 and a second spring 53. The second chair back 2 is provided with a first sinking groove 21, and the sliding bracket 51 is fixedly arranged in the first sinking groove 21; the sliding member 52 is sleeved on the sliding bracket 51, and the sliding bracket 51 is provided with two first slide grooves 511 on the side close to the second chair back 2, and the second spring 53 is arranged in the first slide groove 511. The sliding member 52 is provided with at least two protrusions 521, and at least two protrusions 521 are relatively arranged in the first slide groove 511. The other side of the sliding bracket 51 is provided with a connecting block 512, and the connecting block 512 is provided with a threaded connecting hole 9. The end of the sliding cylinder 41 away from the adjusting knob 43 is provided with a mounting port, and the connecting block 512 is sleeved In the installation opening, the wall of the sliding cylinder 41 is provided with a connecting hole 8, and the external bolts pass through the connecting hole 8 and the threaded connecting hole 9 to fix the sliding bracket 51 with the sliding cylinder 41; when the sliding member 52 drives the second chair back 2 to slide downward, the protrusion 521 squeezes the second spring 53 to generate elastic force, and the second spring 53 is released to reset the second chair back 2. In conjunction with the horizontal movement mechanism 4, the user can adjust the second chair back 2 to any position in the horizontal and vertical directions, and the spring can provide elastic supporting force for the second chair back 2, so that when the second chair back 2 moves relative to the user's waist, it can ensure that the second chair back 2 closely follows the user's waist, and the user only needs to drive the movement of the second chair back 2 through the friction resistance during the waist movement, without deliberately adjusting the second chair back 2 in other ways.

[0046] In another embodiment, all the technical features of the above-mentioned embodiments are included, at least one limit groove 522 is provided on one side of the sliding member 52, a first slot hole is provided on the slot wall opposite to the first sinking groove 21 and the limit groove 522, a limit adjustment rod and a fixing member are provided on the second chair back 2, the fixing member is fixedly arranged in the first slot hole, the limit adjustment rod is sleeved in the cavity of the fixing member, the limit adjustment rod is movably connected to the fixing member, one end of the limit adjustment rod is mutually engaged with the limit groove 522 through the first slot hole, the position of the elastic lifting mechanism 5 can be locked through the limit adjustment rod and fixed to the height desired by the user, similarly, on the horizontal movement mechanism 4, the horizontal position of the second chair back 2 can be fixed by cooperating with the limit column on the limit knob and the first through hole 311 on the sliding cylinder 41, and the user can adjust it to the most comfortable position at will and keep it unchanged through the limit adjustment rod and the limit knob.

[0047] In another embodiment, all the technical features of the above-mentioned embodiments are included. At least one sliding wheel 45 is symmetrically arranged on the outer wall surface of the sliding cylinder 41, and the sliding wheel 45 is fixedly connected to the sliding cylinder 41. At least one guide column 311 is arranged on the inner wall surface of the fixed cylinder 31. The guide column 311 is integrally formed with the fixed cylinder 31. A guide groove 312 is arranged on the guide column 311. The two guide columns 311 have one side with the guide groove 312 arranged opposite to each other. At least one sliding wheel 45 is embedded between the two guide grooves 312. Through the cooperation between the sliding wheel 45 and the guide groove 312, the sliding cylinder 41 can slide. The sliding wheel 45 can be configured as a rotatable roller, and two groups are arranged on both sides of the sliding cylinder 41. Compared with the prior art that slides by the surface friction between the slider rails, the present application sets the motion structure to a spherical shape, and configures the friction between the surfaces as the friction between points and surfaces, thereby reducing the friction generated between the sliding wheel 45 and the guide groove 312, and solving the problem of the second chair back 2 sliding unsmoothly due to the large friction generated between the surfaces. Therefore, the sliding of the roller can make the extension and retraction of the second chair back 2 more natural and easy, thereby improving the user experience.

[0048] In another embodiment, all the technical features of the above-mentioned embodiments are included, at least one limiting through hole 411 is provided on the wall surface of the sliding cylinder 41, and the outer wall surface of the fixed cylinder forms a first connecting cylinder 6 with an opening at one end, and the first connecting cylinder 6 has an open end sleeved with a limiting knob 7, and the limiting knob 7 is movably connected to the first connecting cylinder 6, and a first through hole is provided on the wall surface where the first connecting cylinder 6 and the sliding cylinder 41 are connected, and the limiting knob 7 is fixedly connected to one end of a limiting column 71, and the other end of the limiting column 71 is mutually embedded with the limiting through hole 411 through the first through hole; a first connecting column 61 with openings at both ends is provided in the first connecting cylinder 6, and two outer screw threads facing each other are symmetrically provided on the outer wall surface of the first connecting column 61 The second connecting tube 72 has an open end, and at least two second connecting columns 73 are symmetrically arranged on the inner wall of the second connecting tube 72. The two second connecting columns 73 clamp the first connecting column 61, and the second connecting column 73 fits the external thread 611. By rotating the limit knob 7, the second connecting column 73 rotates along the thread diameter of the external thread 611, and the limit column 71 is extended into or extended out of the limit through hole 411. The user can arbitrarily change the forward and backward movement position of the sliding tube within a certain range. Combined with the limit adjustment rod on the second chair back that fixes the elastic lifting mechanism, the user can freely adjust the horizontal and height position of the fixed second chair back.

[0049] The advantages of the utility model are:

[0050] 1) The second chair back provides dynamic support for the user's waist through the horizontal movement mechanism and the elastic lifting mechanism. It can provide dynamic support for the waist when the user switches to any sitting posture, adaptively track the waist, and the lumbar support has a high degree of freedom of movement, which improves the user's comfortable experience and relieves the fatigue and soreness of the waist caused by the user when sitting for a long time.

[0051] The above disclosures are only several specific embodiments of the present invention, but the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A chair back structure that allows a user to obtain dynamic support when switching between different sitting postures, characterized in that: include: First Chair Back; A chair back bracket, wherein the first chair back is fixedly connected to one end of the chair back bracket, and the other end of the chair back bracket is movably connected to the seat; A horizontal movement mechanism, wherein the chair back support is sleeved on one end of the horizontal movement mechanism, an elastic lifting mechanism is provided at the other end of the horizontal movement mechanism, one end of the elastic lifting mechanism is fixedly connected to the horizontal movement mechanism, and a second chair back is provided at the other end of the elastic lifting mechanism, and the second chair back is movably connected to the elastic lifting mechanism; During operation, the second chair back performs composite movements in front-back and up-down directions simultaneously through the horizontal movement mechanism and the elastic lifting mechanism.

2. The chair back structure according to claim 1 that allows the user to obtain dynamic support when switching between different sitting postures, characterized in that: The horizontal movement mechanism includes a sliding cylinder with an opening at one end, a first spring and an adjusting knob; the chair back bracket is provided with a fixed cylinder with openings at both ends, and the chair back bracket is sleeved on the fixed cylinder; the adjusting knob is movably connected to one end of the fixed cylinder; the end face of the adjusting knob is provided with a positioning column, and the positioning column is sleeved on the first spring, the sliding cylinder and the fixed cylinder in sequence; the sliding cylinder is slidably matched with the fixed cylinder, and one end of the sliding cylinder close to the elastic lifting mechanism is fixedly connected to the elastic lifting mechanism; one end of the first spring is fixed to the end face of the adjusting knob, and the other end abuts against the inner end face of the sliding cylinder.

3. The chair back structure according to claim 2, which allows the user to obtain dynamic support when switching between different sitting postures, is characterized in that: The elastic lifting mechanism includes a sliding bracket, a sliding member and at least one second spring, the second seat back is provided with a first recessed groove, the sliding bracket is fixedly arranged in the first recessed groove; the sliding member is sleeved on the sliding bracket, the sliding bracket is provided with at least two first sliding grooves on a surface close to the second seat back, the second spring is arranged in the first sliding groove, and the sliding member is provided with at least two protrusions, one of the protrusions correspondingly extends into one of the first sliding grooves, and one of the protrusions correspondingly abuts against one of the second springs; a connecting block is provided on the other surface of the sliding bracket, a threaded connecting hole is provided on the connecting block, an installation port is provided at one end of the sliding cylinder away from the adjusting knob, the connecting block is sleeved in the installation port, a connecting hole is provided on the wall surface of the sliding cylinder, and an external bolt passes through the connecting hole and the threaded connecting hole to fix the sliding bracket with the sliding cylinder.

4. The chair back structure for allowing a user to obtain dynamic support when switching between different sitting postures according to claim 3, characterized in that: At least one limit groove is provided on one side of the sliding member, a first slot hole is provided on the slot wall of the first sinking groove opposite to the limit groove, a limit adjustment rod and a fixing member are provided on the second chair back, the fixing member is fixedly arranged in the first slot hole, the limit adjustment rod is sleeved in the cavity of the fixing member, the limit adjustment rod is movably connected to the fixing member, and one end of the limit adjustment rod is interlocked with the limit groove through the first slot hole.

5. The chair back structure for allowing a user to obtain dynamic support when switching between different sitting postures according to claim 2, characterized in that: At least one limiting through hole is provided on the wall surface of the sliding cylinder, and the outer wall surface of the fixed cylinder forms a first connecting cylinder with an open end. The first connecting cylinder has an open end and is sleeved with a limiting knob. The limiting knob is movably connected to the first connecting cylinder, and a first through hole is provided on the wall surface where the first connecting cylinder and the sliding cylinder are connected. The limiting knob is fixedly connected to one end of a limiting column, and the other end of the limiting column is interlocked with the limiting through hole through the first through hole.

6. The chair back structure for allowing a user to obtain dynamic support when switching between different sitting postures according to claim 2, characterized in that: At least one sliding wheel is symmetrically arranged on the outer wall surface of the sliding cylinder, and the sliding wheel is fixedly connected to the sliding cylinder; at least one guide column is arranged on the inner wall surface of the fixed cylinder, and the guide column is integrally formed with the fixed cylinder, and a guide groove is arranged on the guide column, and two guide columns have one side with the guide groove arranged opposite to each other, and at least one sliding wheel is embedded between the two guide grooves.

7. The chair back structure for allowing a user to obtain dynamic support when switching between different sitting postures according to claim 5, characterized in that: A first connecting column with openings at both ends is provided in the first connecting tube, and two external threads facing each other are symmetrically provided on the outer wall surface of the first connecting column. The end surface where the limit knob is connected to the limit column is also provided with a second connecting tube with an opening at one end, and at least two second connecting columns are symmetrically provided on the inner wall of the second connecting tube, and the two second connecting columns clamp the first connecting column, and the second connecting column fits the external thread.

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