Two-way top support waist rest structure office chair

Abstract

The utility model discloses a two -way roof props waist rest structure office chair, including five star foot support frame, the lower side of five star foot support frame is rotatably connected with the evenly distributed trundle, and the inside fixed connection of five star foot support frame has the gas pressure pole, and the telescopic end upper side of gas pressure pole is equipped with the adjustable chair back, and the right side of chair back is equipped with adjustable movable mounting bracket, still includes adjusting mechanism, adjusting mechanism: it includes sliding block no.

Description

Technical Field

[0001] This utility model relates to the field of office chair technology, specifically to an office chair with a two-way top support and lumbar support structure. Background Technology

[0002] When people work, especially in clerical work, they usually sit in office chairs. As people pay more and more attention to office health, office chairs with lumbar support have become the mainstream in the market. Lumbar support provides support for the user's lumbar spine, maintains the physiological curvature of the lumbar spine in the human body in a sitting posture, and reduces lumbar muscle fatigue and intervertebral disc pressure. The existing two-way top support lumbar support structure office chair uses a slider embedded in a slide rail, which moves the slider and drives the lumbar support structure to move. Then, the lumbar support structure is fixed by friction or buckles. While these types of office chairs with a two-way support lumbar support structure can adjust the position of the lumbar support structure, the angle of the lumbar support structure is fixed during the adjustment process. However, the lumbar segment of the human spine is not a simple arc; its curvature changes continuously from the upper thoracic and lumbar vertebrae to the lower lumbosacral vertebrae. Therefore, we propose an office chair with a two-way support lumbar support structure. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to overcome the existing defects and provide a two-way top support lumbar support structure office chair. Through the adjustment mechanism, while adjusting the position of the top support plate, the tilt angle of the top support plate can be changed, thus better conforming to the human waist and being more comfortable than a lumbar support with a fixed angle. This can effectively solve the problems in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a two-way top-support lumbar support structure office chair, including a five-star foot support frame, with evenly distributed casters rotatably connected to the lower side of the five-star foot support frame, a gas spring fixedly connected inside the five-star foot support frame, an adjustable backrest on the upper side of the telescopic end of the gas spring, an adjustable movable mounting bracket on the right side of the backrest, and an adjustment mechanism. Adjustment mechanism: It includes a second slider, a second fixed seat, a top support plate, a connecting rod, a sliding rod, a limiting rod, and a second limiting plate. The second slider is slidably connected to the inside left side of the movable mounting frame. The second fixed seat is fixedly connected to the left surface of the second slider. The top support plate is rotatably connected to both the upper and lower sides of the left surface of the second fixed seat. The sliding rod is slidably connected inside the second fixed seat. The left end of the sliding rod is rotatably connected to the top support plate through the connecting rod. The limiting rod is fixedly connected to the inside of the sliding rod. The second limiting plate is fixedly connected to the rear side of the left surface of the movable mounting frame. The second limiting plate has a second limiting groove on its front surface. The limiting rod is slidably connected in the second limiting groove. Through the adjustment mechanism, while adjusting the position of the top support plate, the tilt angle of the top support plate can be changed, thus better conforming to the human waist and being more comfortable than a lumbar support with a fixed angle.

[0005] Furthermore, the adjustment mechanism also includes a fixed base, a screw, a slider, a fixed rod, a limiting plate, and a limiting groove. The fixed base is fixedly connected to the lower surface of the chair back. The left end of the movable mounting bracket is slidably connected to the inner right side of the fixed base. The screw is rotatably connected to the inside of the fixed base. The outer surface of the screw is threadedly connected to the slider. The lower surface of the slider is slidably connected to the inner lower surface of the fixed base. The right surface of the slider is fixedly connected to the fixed rod. The left end of the movable mounting bracket is fixedly connected to the limiting plate. The upper surface of the limiting plate has a limiting groove. The right end of the fixed rod is slidably connected to the limiting groove to adjust the lateral position of the top support plate.

[0006] Furthermore, the adjustment mechanism also includes a screw three, a bevel gear two, and a rotating rod. The screw three is rotatably connected to the inside right side of the movable mounting frame. The slider two is threadedly connected to the outer surface of the screw three. A bevel gear one is fixedly connected to the lower side of the outer surface of the screw three. A rotating rod is rotatably connected to the front side of the movable mounting frame. A bevel gear two is fixedly connected to the rear side of the outer surface of the rotating rod. The bevel gear two meshes with the bevel gear one to transmit driving force and provide locking.

[0007] Furthermore, a base is fixedly connected to the outer surface of the telescopic end of the gas spring, a rotating shaft is rotatably connected inside the base, a movable seat is fixedly connected to the outer surface of the rotating shaft, and the upper surface of the movable seat is fixedly connected to the lower surface of the chair back, thus connecting the chair back and the gas spring.

[0008] Furthermore, a bolt is slidably connected to the left side of the upper surface of the base, and an adjusting cylinder is threadedly connected to the lower side of the outer surface of the bolt. A conical spring is fixedly connected between the lower inner surface of the adjusting cylinder and the lower surface of the base. The conical spring is sleeved on the outside of the bolt. An clearance groove is provided on the left side of the upper surface of the movable seat. The upper end of the bolt is slidably connected to the clearance groove. A fixing block is fixedly connected to the upper end of the bolt, so that the backrest angle can be automatically restored after adjustment.

[0009] Furthermore, the lower surface of the movable seat is rotatably connected with evenly distributed rotating plates, each of which has a slot. The front surface of the base is threaded with a screw rod, and the outer surface of the screw rod is fixedly connected with evenly distributed locking plates. The screw rod is located inside the longitudinally adjacent slots to lock the chair back.

[0010] Furthermore, a lever is rotatably connected to the rear inner side of the base, and a paddle is fixedly connected to the front outer side of the lever. The paddle is located on the upper side of the pneumatic rod and controls the opening and closing of the valve inside the pneumatic rod.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: This two-way top-support lumbar support structure office chair has the following advantages: The adjustment mechanism allows for changes in the tilt angle of the top support plate while adjusting its position, thus making it more comfortable to fit the human waist and providing greater comfort than a lumbar support with a fixed angle. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a front view structural diagram of the present invention; Figure 3 This is a partial structural diagram of the present invention; Figure 4 This is an enlarged structural diagram of point A in this utility model; Figure 5 This is a cross-sectional view of the movable seat of this utility model; Figure 6 This is an enlarged structural diagram of section B of the present invention; Figure 7 This is a partial structural schematic diagram of the adjustment mechanism of this utility model; Figure 8 This is a cross-sectional view of the movable mounting bracket of this utility model.

[0013] In the diagram: 1. Five-star foot support frame; 2. Gas spring; 3. Chair back; 4. Movable mounting bracket; 5. Adjustment mechanism; 501. Fixed seat one; 502. Screw two; 503. Slider one; 504. Fixed rod; 505. Limiting plate one; 506. Limiting groove one; 507. Slider two; 508. Fixed seat two; 509. Top support plate; 510. Connecting rod; 511. Slide rod; 512. Limiting rod; 513. Limiting plate two; 514. Screw three; 515. Bevel gear two; 516. Rotating rod; 6. Base; 7. Movable seat; 8. Rotating shaft; 9. Fixed block; 10. Adjustment cylinder; 11. Conical spring; 12. Bolt; 13. Screw one; 14. Locking plate; 15. Rotating plate; 16. Lever; 17. Lever. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] Please see Figure 1-8This embodiment provides a technical solution: a two-way top-support lumbar support structure office chair, including a five-star foot support frame 1. The lower side of the five-star foot support frame 1 is rotatably connected to evenly distributed casters. The five-star foot support frame 1 is internally fixedly connected to a gas rod 2. The gas rod 2 can be a gas rod commonly used in the prior art. It is an elastic element that uses gas and liquid as working medium. It is often installed in the upper end of the inner cylinder as a key component of pneumatic lifting chairs. It has functions such as support, buffer, braking and height and angle adjustment. It is mainly composed of components such as valve, inner tube, piston rod, piston and outer tube. Its working principle is based on the pressure difference formed at both ends of the piston by the high-pressure nitrogen gas. When the external force is applied to the piston rod, the gas is compressed and stored energy. After the external force is removed, the stored energy is released and pushes the piston to reset, thereby realizing the lifting function. The upper side of the telescopic end of the gas rod 2 is provided with an adjustable backrest 3. The right side of the backrest 3 is provided with an adjustable movable mounting bracket 4. It also includes an adjustment mechanism 5. Adjustment mechanism 5 includes a second slider 507, a second fixed seat 508, a top support plate 509, a connecting rod 510, a sliding rod 511, a limiting rod 512, and a second limiting plate 513. The second slider 507 is slidably connected to the inside left side of the movable mounting frame 4. The second fixed seat 508 is fixedly connected to the left surface of the second slider 507. The top support plate 509 is rotatably connected to both the upper and lower sides of the left surface of the second fixed seat 508. The sliding rod 511 is slidably connected inside the second fixed seat 508. The left end of the sliding rod 511 is rotatably connected to the top support plate 509 through the connecting rod 510. The sliding rod 511 is fixedly connected to the limiting plate 513. The positioning rod 512 is fixedly connected to the rear side of the left surface of the movable mounting frame 4 by a limiting plate 513. A limiting groove is formed on the front surface of the limiting plate 513, and the limiting rod 512 is slidably connected within the limiting groove. The adjusting mechanism 5 also includes a screw 514, a bevel gear 515, and a rotating rod 516. The screw 514 is rotatably connected to the right side of the interior of the movable mounting frame 4. A slider 507 is threadedly connected to the outer surface of the screw 514. Corrugated pipes are fixedly connected between the upper and lower surfaces of the slider 507 and the inner wall of the movable mounting frame 4. The corrugated pipes are all fitted onto the outer surface of the screw 514, thereby adjusting the screw 514... To protect the screw 514 from external impurities adhering to its outer surface and affecting its normal operation, a bevel gear 1 is fixedly connected to the lower side of the outer surface of the screw 514. A rotating rod 516 is rotatably connected to the front side of the movable mounting bracket 4. A bevel gear 2 515 is fixedly connected to the rear side of the outer surface of the rotating rod 516. The bevel gear 2 515 meshes with the bevel gear 1. Rotating the rotating rod 516 causes the bevel gear 2 515 to rotate, which in turn causes the bevel gear 1 to rotate, thus rotating the screw 514. This causes the slider 2 507 to move along the direction of the screw 514, thereby moving the fixed seat 2 508. This causes the top support plate 509 to move vertically, thereby adjusting the support position of the top support plate 509 on the human waist. When the second fixed seat 508 moves upward, it causes the limiting rod 512 to move within the second limiting groove, causing the sliding rod 511 to move to the right, causing the top support plate 509 to rotate around the rotation connection point between the top support plate 509 and the second fixed seat 508, making the two top support plates 509 more vertical and thus conforming to the relatively flat body curve of the human chest and waist. When the second fixed seat 508 moves upward, the sliding rod 511 moves to the left, making the inclination angle between the two top support plates 509 larger, thus conforming to the deeper body curve of the lumbosacral region. The adjustment mechanism 5 also includes a fixed base 501, a screw 502, a slider 503, a fixed rod 504, a limiting plate 505, and a limiting groove 506. The fixed base 501 is fixedly connected to the lower surface of the chair back 3. The left end of the movable mounting bracket 4 is slidably connected to the inner right side of the fixed base 501. The screw 502 is rotatably connected inside the fixed base 501. The slider 503 is threadedly connected to the outer surface of the screw 502. The lower surface of the slider 503 is slidably connected to the inner lower surface of the fixed base 501. Corrugated pipes are fixedly connected between the front and rear surfaces of the slider 503 and the inner wall of the fixed base 501. The corrugated pipes are all sleeved on the outer surface of the screw 502 to protect the screw 502 and prevent external impurities from adhering to the outer surface of the screw 502, thus affecting the normal use of the screw 502. The right surface of the slider 503... A fixed rod 504 is fixedly connected to the surface. A limiting plate 505 is fixedly connected to the left end of the movable mounting frame 4. A limiting groove 506 is opened on the upper surface of the limiting plate 505. The right end of the fixed rod 504 is slidably connected in the limiting groove 506. When it is necessary to adjust the position of the top support plate 509, rotate the screw 502 to move the slider 503, drive the fixed rod 504 to move, and move the right end of the fixed rod 504 in the limiting groove 506. This will drive the limiting plate 505 to move, move the movable mounting frame 4, drive the slider 507 to move, move the fixed seat 508 to move, and then drive the top support plate 509 to move laterally, thereby adjusting the amount of thrust of the top support plate 509 on the waist. A high-performance engineering polyester fiber elastic mesh is fixedly connected to the inside right side of the backrest 3. All the positions that the top support plate 509 contacts are the right surface of the high-performance engineering polyester fiber elastic mesh. A base 6 is fixedly connected to the outer surface of the telescopic end of the gas spring 2. A rotating shaft 8 is rotatably connected inside the base 6. A movable seat 7 is fixedly connected to the outer surface of the rotating shaft 8. The upper surface of the movable seat 7 is fixedly connected to the lower surface of the chair back 3. A bolt 12 is slidably connected to the left side of the upper surface of the base 6. An adjusting cylinder 10 is threadedly connected to the lower side of the outer surface of the bolt 12. A conical spring 11 is fixedly connected between the lower inner surface of the adjusting cylinder 10 and the lower surface of the base 6. The conical spring 11 is sleeved on the outside of the bolt 12. The adjusting cylinder 10 can be removed from the outer surface of the bolt 12 to replace the conical spring 11, preventing the conical spring 11 from weakening after long-term use and becoming unusable. A clearance groove is provided on the left side of the upper surface of the movable seat 7. The upper end of the bolt 12 is slidably connected to the clearance groove. A fixing block 9 is fixedly connected to the upper end of the bolt 12. When it is necessary to adjust the angle of the chair back 3... Rotate screw 13 to move it forward, causing locking piece 14 to move and separating it from rotating piece 15. The number of locking pieces 14 and rotating pieces 15 is the same, and each locking piece 14 is located in front of the adjacent rotating piece 15. At this time, there is no friction between locking piece 14 and rotating piece 15, thereby releasing the lock on movable seat 7 and allowing movable seat 7 to rotate around the central axis of rotating shaft 8. When movable seat 7 moves, it causes bolt 12 to move. The clearance groove allows relative movement between bolt 12 and movable seat 7. Fixing block 9 prevents bolt 12 from moving to the lower side of clearance groove. When bolt 12 moves, it causes adjusting cylinder 10 to move and conical spring 11 to contract. Adjusting cylinder 10 can be rotated to move along the direction of bolt 12, thereby adjusting the tightness of conical spring 11 and adjusting the force required to adjust the angle of movable seat 7. The lower surface of the movable base 7 is rotatably connected to evenly distributed rotating plates 15, each of which has a slot. A screw 13 is threadedly connected to the front surface of the base 6, allowing for the fixed connection of protective covers to both the front and rear surfaces of the base 6. Each protective cover has an avoidance groove corresponding to the screw 13. Corrugated tubes 3 are fixedly connected between the front and rear surfaces of the base 6 and the inner wall of the protective cover on the same side. These corrugated tubes 3 are fitted onto the outer surface of the screw 13, thus protecting it and preventing external impurities from adhering to it. The outer surface of screw 13 may affect its normal use. The front surface of movable seat 7 is provided with an arc-shaped clearance groove that can accommodate the protective cover. The outer surface of screw 13 is fixedly connected with evenly distributed locking pieces 14. Screw 13 is located inside the longitudinally adjacent slots. After the angle of movable seat 7 is adjusted, screw 13 is reversed to move the locking pieces 14 and make them fit with the rotating pieces 15, thereby generating friction between the locking pieces 14 and the rotating pieces 15 to lock the movable seat 7. A lever 16 is rotatably connected to the rear side of the inner side of the base 6. A paddle 17 is fixedly connected to the front side of the outer surface of the lever 16. The paddle 17 is located on the upper side of the gas spring 2. An arc-shaped clearance groove is provided on the rear surface of the movable seat 7. The lever 16 is located in the arc-shaped clearance groove. When the user sits on the backrest 3 and needs to adjust the height of the backrest 3, the lever 16 is rotated, causing the paddle 17 to rotate around the central axis of the lever 16. The paddle 7 contacts and presses down on the valve on the upper side of the telescopic end of the gas spring 2, thereby opening the valve. The gas spring 2 is composed of components such as a valve, an inner tube, a piston rod, a piston, and an outer tube. When the valve is open, the inner tube and the outer tube are connected, and the inner and outer tubes are connected. When the air pressure is equal, the user's body weight forces the inner tube inside the gas spring 2 to retract into the outer tube, thus lowering the chair height. When the user leaves the seat and pulls the control lever again, although the air pressure on the inner and outer sides is the same, the upper and lower surface areas of the piston are different. According to the principle that pressure is proportional to force, the pressure difference under the upper surface of the piston pushes the inner tube upward, raising the chair. Once the desired height is reached, releasing the lever 16 resets the valve due to the spring force inside the gas spring 2, closing the valve and sealing the nitrogen in the cylinder. The strong pressure of the nitrogen locks the height firmly, stabilizing the chair in the new position and providing stable support.

[0016] The working principle of the two-way top support lumbar support structure office chair provided by this utility model is as follows: When using this two-way top support lumbar support structure office chair, the user sits on the backrest 3. When it is necessary to adjust the height of the backrest 3, rotate the lever 16 so that the lever 17 rotates around the central axis of the lever 16. The lever 7 contacts and presses down on the valve on the upper side of the telescopic end of the gas rod 2, thereby opening the valve. The gas rod 2 is composed of components such as valve, inner tube, piston rod, piston and outer tube. When the valve is open, the inner tube and outer tube are connected and the air pressure between the inner and outer tubes is equal. The weight of the user's body will force the inner tube inside the gas rod 2 to retract into the outer tube, thereby lowering the chair height.When the user leaves the seat and pulls the control lever, although the air pressure on the inner and outer sides is the same, the upper and lower surface areas of the piston are different. Since pressure is proportional to force, the pressure difference between the upper and lower surfaces of the piston pushes the inner tube upwards, raising the chair. Once the desired height is reached, releasing lever 16 resets the valve due to the spring force inside the pneumatic lever 2, closing the valve and sealing the nitrogen gas in the cylinder. This strong pressure firmly locks the height, stabilizing the chair in the new position and providing stable support. When the angle of the backrest 3 needs adjustment, rotating screw 13 moves it forward, causing locking plate 14 to move and separating it from rotating plate 15. The locking plates 14 are all the same number and located in front of the adjacent rotating plates 15. At this time, there is no friction between the locking plates 14 and the rotating plates 15, thus releasing the lock on the movable seat 7 and allowing the movable seat 7 to rotate around the central axis of the rotating shaft 8. When the movable seat 7 moves, it drives the bolt 12 to move. The clearance groove allows relative movement between the bolt 12 and the movable seat 7. The fixing block 9 prevents the bolt 12 from moving to the lower side of the clearance groove. When the bolt 12 moves, it causes the adjusting cylinder 10 to move and the conical spring 11 to contract. After the angle of the movable seat 7 is adjusted, the reverse screw 13 is reversed, causing the locking plates 14 to move and fit against the rotating plates 15. This generates friction between the locking plates 14 and the rotating plates 15 to lock the movable seat 7, which can be rotated for adjustment. The adjusting cylinder 10 is moved along the direction of the bolt 12, thereby adjusting the tightness of the conical spring 11, which in turn adjusts the force required to adjust the angle of the movable seat 7. When the position of the top support plate 509 needs to be adjusted, the screw 2 502 is rotated, causing the slider 1 503 to move, which in turn moves the fixed rod 504, causing the right end of the fixed rod 504 to move within the limiting groove 1 506, which in turn moves the limiting plate 1 505, causing the movable mounting bracket 4 to move, which in turn moves the slider 2 507, causing the fixed seat 2 508 to move, which in turn moves the top support plate 509 laterally, thereby adjusting the thrust of the top support plate 509 on the human waist. The rotating rod 516 is rotated, causing the bevel gear 2 515 to rotate, which in turn moves the bevel gear Rotation causes screw 3 514 to rotate, driving slider 2 507 to move along the direction of screw 3 514, causing fixed seat 2 508 to move, which in turn causes top support plate 509 to move vertically, thereby adjusting the support position of top support plate 509 on the human waist. When fixed seat 2 508 moves upward, it drives limit rod 512 to move within limit groove 2, causing slide rod 511 to move to the right, causing top support plate 509 to rotate around the rotational connection point between top support plate 509 and fixed seat 2 508, making the two top support plates 509 more vertical and thus conforming to the relatively flat body curve of the thoracolumbar region. When fixed seat 2 508 moves upward, slide rod 511 moves to the left, increasing the inclination angle between the two top support plates 509, thus conforming to the deeper body curve of the lumbosacral region.

[0017] The above are merely embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A two-way top-support lumbar support office chair, comprising a five-star base support frame (1), wherein the lower side of the five-star base support frame (1) is rotatably connected to evenly distributed casters, and a gas spring (2) is fixedly connected inside the five-star base support frame (1). An adjustable backrest (3) is provided on the upper side of the telescopic end of the gas spring (2), and an adjustable movable mounting bracket (4) is provided on the right side of the backrest (3). The chair is characterized by: It also includes a regulating mechanism (5); Adjustment mechanism (5): It includes slider two (507), fixed seat two (508), top support plate (509), connecting rod (510), sliding rod (511), limiting rod (512) and limiting plate two (513). Sliding slider two (507) is slidably connected to the inside left side of the movable mounting frame (4). Fixed seat two (508) is fixedly connected to the left surface of slider two (507). Top support plate two (513) is rotatably connected to the upper and lower sides of the left surface of fixed seat two (508). 09), the sliding rod (511) is slidably connected inside the fixed seat (508). The left end of the sliding rod (511) and the top support plate (509) are rotatably connected by the connecting rod (510). The sliding rod (511) is fixedly connected to the inside of the limiting rod (512). The left rear side of the movable mounting frame (4) is fixedly connected to the limiting plate (513). The front surface of the limiting plate (513) is provided with the limiting groove (2). The limiting rod (512) is slidably connected in the limiting groove (2).

2. The office chair with a two-way top support lumbar support structure according to claim 1, characterized in that: The adjustment mechanism (5) further includes a fixed seat (501), a screw (502), a slider (503), a fixed rod (504), a limiting plate (505), and a limiting groove (506). The fixed seat (501) is fixedly connected to the lower surface of the chair back (3). The left end of the movable mounting bracket (4) is slidably connected to the inside right side of the fixed seat (501). The screw (502) is rotatably connected inside the fixed seat (501). 2) The outer surface is threaded with a slider (503). The lower surface of the slider (503) is slidably connected to the inner lower surface of the fixed seat (501). The right surface of the slider (503) is fixedly connected with a fixed rod (504). The left end of the movable mounting bracket (4) is fixedly connected with a limiting plate (505). The upper surface of the limiting plate (505) is provided with a limiting groove (506). The right end of the fixed rod (504) is slidably connected to the limiting groove (506).

3. The office chair with a two-way top support lumbar support structure according to claim 1, characterized in that: The adjustment mechanism (5) also includes a screw three (514), a bevel gear two (515) and a rotating rod (516). The screw three (514) is rotatably connected to the inside right side of the movable mounting frame (4). The slider two (507) is threadedly connected to the outer surface of the screw three (514). A bevel gear one is fixedly connected to the lower side of the outer surface of the screw three (514). A rotating rod (516) is rotatably connected to the front side of the movable mounting frame (4). A bevel gear two (515) is fixedly connected to the rear side of the outer surface of the rotating rod (516). The bevel gear two (515) meshes with the bevel gear one.

4. The office chair with a two-way top support lumbar support structure according to claim 1, characterized in that: The outer surface of the telescopic end of the pneumatic rod (2) is fixedly connected to a base (6), and the inside of the base (6) is rotatably connected to a rotating shaft (8). The outer surface of the rotating shaft (8) is fixedly connected to a movable seat (7), and the upper surface of the movable seat (7) is fixedly connected to the lower surface of the chair back (3).

5. The office chair with a two-way top-support lumbar support structure according to claim 4, characterized in that: A bolt (12) is slidably connected to the left side of the upper surface of the base (6). An adjusting cylinder (10) is threadedly connected to the lower side of the outer surface of the bolt (12). A conical spring (11) is fixedly connected between the lower inner surface of the adjusting cylinder (10) and the lower surface of the base (6). The conical spring (11) is sleeved on the outside of the bolt (12). An clearance groove is provided on the left side of the upper surface of the movable seat (7). The upper end of the bolt (12) is slidably connected to the clearance groove. A fixing block (9) is fixedly connected to the upper end of the bolt (12).

6. The office chair with a two-way top-support lumbar support structure according to claim 4, characterized in that: The lower surface of the movable seat (7) is rotatably connected with evenly distributed rotating plates (15), and the interior of each rotating plate (15) is provided with a slot. The front surface of the base (6) is threadedly connected with a screw rod (13), and the outer surface of the screw rod (13) is fixedly connected with evenly distributed locking plates (14). The screw rod (13) is located inside the longitudinally adjacent slots.

7. The office chair with a two-way top-support lumbar support structure according to claim 4, characterized in that: The base (6) is rotatably connected to the rear side of the interior, and a lever (16) is fixedly connected to the front side of the outer surface of the lever (16). The lever (17) is located on the upper side of the pneumatic rod (2).

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