Waist rest connecting rod adjusting device

Abstract

The utility model discloses a waist rest connecting rod adjusting device which comprises a backrest body and a waist rest body, the upper end of the waist rest body is hinged to the backrest body, the lower end of the waist rest body is connected with the backrest body through a connecting rod sliding groove structure, and the connecting rod sliding groove structure comprises an adjusting piece and a sliding groove. The sliding groove is formed in one of the backrest body and the waist rest body in the length direction, one end of the adjusting piece is slidably connected to the sliding groove, and the other end of the adjusting piece is hinged to the other one of the backrest body and the waist rest body. When one end of the adjusting piece slides up and down along the sliding groove, the waist rest body is pushed or pulled by the adjusting piece so as to rotate front and back relative to the backrest body. A telescopic adjusting mechanism is further arranged between the backrest body and the waist rest body. According to the waist rest connecting rod adjusting device, the upper end and the lower end of the waist rest body are supported by the backrest body and the adjusting piece respectively, stability is good, and the supporting strength is high; and the waist rest body can be fixed at any inclination angle, so that the degree of freedom is high.

Description

Technical Field

[0001] This utility model generally relates to the field of seat technology, and specifically to a lumbar support linkage adjustment device. Background Technology

[0002] A lumbar support is a common component in chairs. It protrudes forward relative to the backrest, supporting the naturally forward-curving lumbar spine, effectively relieving lower back fatigue, preventing scoliosis, and protecting the lower back. Traditional lumbar supports are fixed to the backrest and cannot be adjusted in depth. However, the distance between the user's lower back and the backrest is often affected by body shape and sitting posture. This means that a fixed-position lumbar support may not be suitable for users of different body types and sitting postures, resulting in poor practicality.

[0003] To address the aforementioned issues, an existing patent provides a seat backrest (application number: CN200620155450.9) with a lumbar support cushion featuring an angle adjustment device. This device includes a connecting plate and brackets, a fixed seat, and a ratchet mechanism located at both ends of the connecting plate. The lumbar support cushion is fixed to the connecting plate, and the brackets are welded to it. A mounting groove is formed at the lower end of the brackets. The ratchet mechanism includes a ratchet and a pawl, hinged to the side walls of the mounting groove. The ratchet is connected to the fixed seat on the bottom plate of the seat backrest. A sector-shaped movable block is also provided at the ratchet hinge point, and a stop bar on the ratchet controls the rotation angle of this sector-shaped movable block. When the lower end of the lumbar support cushion is raised, it drives the pawl to rotate via the ratchet's hinge pin. Simultaneously, the pawl rotates the sector-shaped movable block. When the desired height is reached, the hand is released. At this point, the pawl, under the spring force, abuts against the bottom of the ratchet gear, preventing the lumbar support cushion from moving in the opposite direction, thus preventing the cushion's height from automatically decreasing when the user's back is resting on it. When the lumbar support pad is raised to its highest point, the stop bar blocks the movement of the fan-shaped moving block, the ratchet and pawl separate, and the lumbar support pad can rotate freely in both directions, thus allowing it to rotate backward to achieve a reset.

[0004] However, the above solution has the following problems: the lumbar support pad is only connected to the backrest base plate through the ratchet mechanism at the top, and the lower end of the lumbar support pad is not supported. When the user's waist presses against the lumbar support pad, the lower end of the lumbar support pad may wobble back and forth, resulting in poor stability. Furthermore, the pressure on the lumbar support pad will be directly applied to the ratchet mechanism. When the user is heavy, the ratchet mechanism may not be able to withstand the huge pressure and is easily damaged, resulting in poor support strength of the lumbar support pad. Moreover, the pawl can only be engaged with the position with the pawl on the ratchet, that is, the lumbar support pad can only be fixed at the preset position, which is a stepped adjustment with low degree of adjustment freedom. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a lumbar support linkage adjustment device, in which the backrest, lumbar support, adjustment component, and slide groove form a structure similar to a three-bar linkage slide groove. When the adjustment component is fixed at a certain position in the slide groove, the upper and lower ends of the lumbar support are supported by the backrest and the adjustment component respectively, making the lumbar support less prone to shaking when compressed, and providing good stability; moreover, the pressure on the lumbar support is dispersed by the backrest and the adjustment component, resulting in good support strength of the lumbar support; in addition, the adjustment component can be fixed at any position on the slide groove, that is, the lumbar support can be fixed at any tilt angle, providing a high degree of adjustment freedom.

[0006] The effect of this utility model is achieved as follows:

[0007] This application provides a lumbar support linkage adjustment device, including a backrest and a lumbar support connected to the front side of the backrest. The upper end of the lumbar support is hinged to the backrest, and the lower end of the lumbar support is connected to the backrest via a linkage slide groove structure. The linkage slide groove structure includes an adjusting member and a slide groove. The slide groove is formed along the length of one of the backrest and the lumbar support. One end of the adjusting member is slidably connected to the slide groove, and the other end is hinged to the other of the backrest and the lumbar support. When one end of the adjusting member slides up and down along the slide groove, the lumbar support is pushed or pulled by the adjusting member, thereby rotating back and forth relative to the backrest. A telescopic adjustment mechanism is also provided between the backrest and the lumbar support. The telescopic adjustment mechanism is configured to adjust the up and down sliding of the adjusting member and can fix the adjusting member at any position on the slide groove.

[0008] Furthermore, the backrest includes a backrest body and a first support plate connected to the front end of the backrest body, and the lumbar support includes a lumbar support body and a second support plate connected to the rear end of the lumbar support body. The upper ends of the first and second support plates are hinged to each other, and a sliding groove is formed on the first support plate along its length. This makes the processing and manufacturing operations of the backrest and lumbar support simpler.

[0009] Furthermore, the upper ends of the first and second support plates are hinged together by butterfly hinges. Butterfly hinges have a simple structure, low cost, and are relatively easy to install and disassemble.

[0010] Furthermore, the first support plate includes a first plate body connected to the backrest body and a first hinge member detachably connected to the front end of the first plate body. The first hinge member is a sheet metal part, and it is bent forward to form a sliding support portion. A sliding groove is formed in the sliding support portion along its length. The first hinge member has a simple overall structure and is relatively easy to process and manufacture. Moreover, the first hinge member is detachably connected to the first plate body, making the assembly operation of the first support plate relatively convenient.

[0011] Furthermore, the first support plate is detachably connected to the backrest body by screws, and the second support plate is detachably connected to the lumbar support body by screws. This not only makes the connection strength between the first support plate and the backrest, and between the second support plate and the lumbar support, more reliable, but also makes the installation and disassembly operations more convenient.

[0012] Furthermore, the telescopic adjustment mechanism includes any one of a gas spring, a hydraulic rod, and an electric actuator. Mechanisms such as gas springs, hydraulic rods, and electric actuators can not only extend and retract to adjust the length, thereby driving the adjusting component to slide, but can also be fixed at any length, thus keeping the lumbar support fixed and simplifying the adjustment operation.

[0013] Furthermore, the telescopic adjustment mechanism is a gas spring, which is installed on the backrest or lumbar support. When the lumbar support rotates forward to its maximum angle, the rear end of the adjusting component is located at the bottom of the slide groove. The gas spring applies a downward thrust to the adjusting component, causing one end of the adjusting component to always have a tendency to slide downward along the slide groove, and causing the other end of the adjusting component to push forward, thus ensuring that the lumbar support always has a tendency to rotate forward relative to the backrest. This forward rotation allows the lumbar support to automatically rotate forward to fit the user's waist when adjusting its tilt angle, eliminating the need for manual adjustment and simplifying the adjustment process.

[0014] Furthermore, the gas spring is equipped with a wired control assembly, which includes an adjustment knob and a pull cord. The adjustment knob is located on one of the left or right sides of the backrest, and the adjustment knob and the gas spring are connected by a pull cord. The adjustment knob is configured to adjust the pull cord to compress or release the pin of the gas spring, thereby controlling the locking or unlocking of the gas spring. The user only needs to turn the adjustment knob on the side wall of the backrest to control the locking or unlocking of the gas spring, thereby controlling the fixation or movement of the lumbar support, making the locking operation of the lumbar support very simple.

[0015] Furthermore, the gas spring can also be a tension-type gas spring: the telescopic adjustment mechanism is a gas spring, which is installed on the backrest or lumbar support; when the lumbar support rotates forward to its maximum angle, the rear end of the adjusting component is at the top of the slide groove. The gas spring applies an upward pulling force to the adjusting component, causing one end of the adjusting component to always have a tendency to slide upward along the slide groove, and causing the other end of the adjusting component to push forward, thus making the lumbar support always have a tendency to rotate forward relative to the backrest. This allows the lumbar support to automatically rotate forward to fit the user's waist when adjusting the tilt angle, without requiring manual adjustment by the user, making the adjustment operation relatively simple.

[0016] The lumbar support linkage adjustment device provided in this application has the upper ends of the backrest and the lumbar support hinged together. An adjusting component slides along a groove, causing the lumbar support to rotate relative to the backrest. This creates a structure similar to a three-bar linkage between the backrest, lumbar support, adjusting component, and groove. This structure is not only simple overall but also allows for smooth rotation and adjustment. Furthermore, when the adjusting component is fixed at a certain position in the groove, the upper and lower ends of the lumbar support are supported by the backrest and the adjusting component respectively. This prevents the lumbar support from wobbling under pressure, ensuring good stability. The pressure on the lumbar support is also dispersed by the backrest and the adjusting component, allowing the lumbar support to withstand greater pressure and providing better support strength. Moreover, by incorporating a telescopic adjustment mechanism, the adjusting component can be fixed at any position on the groove, meaning the lumbar support can be fixed at any tilt angle, offering a high degree of adjustment freedom. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0018] Figure 1 A three-dimensional structural schematic diagram of the lumbar support linkage adjustment device provided in the embodiments of this application;

[0019] Figure 2 A side view of the lumbar support linkage adjustment device when the lumbar support is rotated to the foremost position according to an embodiment of this application;

[0020] Figure 3 A side view of the lumbar support linkage adjustment device when the lumbar support is rotated to its final position according to an embodiment of this application;

[0021] Figure 4 A schematic diagram of the connection structure between the lumbar support and the backrest provided in an embodiment of this application;

[0022] Figure 5 A schematic diagram of the connection structure between the telescopic adjustment mechanism and the first support plate provided in the embodiments of this application;

[0023] Figure 6 A schematic diagram of the connection structure between the adjusting member and the lumbar support provided in an embodiment of this application;

[0024] Figure 7 A side view of the lumbar support linkage adjustment device provided in the embodiment of this application when the slide groove is set on the lumbar support;

[0025] Figure 8 A schematic diagram illustrating the change process of the lumbar support when using a tension-type gas spring, provided as an embodiment of this application;

[0026] The reference numerals in the attached figures are as follows: 1-backrest, 1a-backrest body, 101-slide groove, 102-butterfly hinge, 110-first support plate, 111-first plate, 120-first hinge, 121-sliding support, 2-lumbar support, 2a-lumbar support body, 210-second support plate, 211-second plate, 220-second hinge, 221-hinge, 3-adjusting component, 3a-support, 3b-connecting component, 4-gas spring, 401-adjusting knob, 402-pull cord. Detailed Implementation

[0027] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the relevant utility model and not intended to limit the scope of the utility model. Furthermore, it should be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings.

[0028] Please refer to the attached document. Figure 1-8 This application provides a lumbar support linkage adjustment device, including a backrest 1 and a lumbar support 2 connected to the front side of the backrest 1. The upper end of the lumbar support 2 is hinged to the backrest 1, and the lower end of the lumbar support 2 is connected to the backrest 1 through a linkage slide groove structure. The linkage slide groove structure includes an adjusting member 3 and a slide groove 101. The slide groove 101 is opened along the length direction in one of the backrest 1 and the lumbar support 2. One end of the adjusting member 3 is slidably connected to the slide groove 101, and the other end is hinged to the other of the backrest 1 and the lumbar support 2. When one end of the adjusting member 3 slides up and down along the slide groove 101, the lumbar support 2 is pushed or pulled by the adjusting member 3, thereby rotating back and forth relative to the backrest 1. A telescopic adjustment mechanism is also provided between the backrest 1 and the lumbar support 2. The telescopic adjustment mechanism is configured to adjust the sliding up and down of the adjusting member 3 and can fix the adjusting member 3 at any position on the slide groove 101.

[0029] In this embodiment, the upper ends of the backrest 1 and the lumbar support 2 are hinged together, and the lumbar support 2 rotates relative to the backrest 1 by sliding along the slide groove 101 through the adjusting member 3. This makes the backrest 1, lumbar support 2, adjusting member 3 and slide groove 101 form a structure similar to a three-bar linkage, which not only has a simple overall structure and smooth rotation adjustment operation, but also, when the adjusting member 3 is fixed at a certain position in the slide groove 101, the upper and lower ends of the lumbar support 2 are supported by the backrest 1 and the adjusting member 3 respectively, so that the lumbar support 2 is not easy to shake when squeezed, and has good stability. Moreover, the pressure on the lumbar support 2 is distributed by the backrest 1 and the adjusting member 3, so that the lumbar support 2 can withstand greater pressure and has better support strength. In addition, by setting a telescopic adjustment mechanism, the adjusting member 3 can be fixed at any position on the slide groove 101, that is, the lumbar support 2 can be fixed at any tilt angle, which is stepless adjustment and has a high degree of adjustment freedom.

[0030] Please refer to the attached document. Figure 4In some embodiments of this application, the backrest 1 includes a backrest body 1a and a first support plate 110 connected to the front end of the backrest body 1a, and the lumbar support 2 includes a lumbar support body 2a and a second support plate 210 connected to the rear end of the lumbar support body 2a. The upper ends of the first support plate 110 and the second support plate 210 are hinged to each other, and the slide groove 101 is opened in the first support plate 110 along the length direction.

[0031] In this embodiment, by setting a plate-shaped first support plate 110 on the backrest body 1a and a second support plate 210 on the lumbar support body 2a, and setting a connecting structure such as a sliding groove 101 between the first support plate 110 and the second support plate 210, the processing and manufacturing operations of the backrest 1 and the lumbar support 2 are made simpler.

[0032] Of course, please refer to the appendix. Figure 7 In other embodiments of this application, the slide groove 101 can also be provided on the second support plate 210. While one end of the adjusting member 3 slides along the slide groove 101, it pushes or pulls the waist support 2, thereby driving the waist support 2 to rotate back and forth.

[0033] Please refer to the attached document. Figure 4 In some embodiments of this application, the upper ends of the first support plate 110 and the second support plate 210 are hinged together by a butterfly hinge. The butterfly hinge 102 not only allows for rotational adjustment between the first support plate 110 and the second support plate 210, but also has a simple structure, low cost, and is fixed to the first support plate 110 and the second support plate 210 by screws, making installation and disassembly relatively convenient.

[0034] The upper ends of the first support plate 110 and the second support plate 210 are hinged by two symmetrical butterfly hinges 102, which makes the rotation adjustment process of the second support plate 210 more stable and the connection strength between the first support plate 110 and the second support plate 210 higher.

[0035] Of course, in other embodiments of this application, the first support plate 110 and the second support plate 210 can also be hinged together by means of a rotating shaft, gear meshing, etc.

[0036] Please refer to the attached document. Figure 5 In some embodiments of this application, the first support plate 110 includes a first plate 111 connected to the backrest body 1a and a first hinge 120 detachably connected to the front end of the first plate 111. The first hinge 120 is a sheet metal part. The first hinge 120 is bent forward to form a sliding support portion 121. A sliding groove 101 is formed in the sliding support portion 121 along the length direction.

[0037] In this embodiment, by setting the slide groove 101 on the first hinge member 120 made of sheet metal, the first hinge member 120 has a simple overall structure and is relatively easy to process and manufacture. Furthermore, the first hinge member 120 is detachably connected to the first plate 111, making the assembly operation of the first support plate 110 more convenient.

[0038] The first hinge 120 is fixed to the first plate 111 by screws, making installation and disassembly convenient. Both ends of the first hinge 120 are bent forward to form sliding support parts 121. The adjusting part 3 and the two side slide grooves 101 are connected in series and hinged together by bolts, which makes the connection between the two stronger and the sliding adjustment operation more stable.

[0039] Please refer to the appendix. Figure 6 The second support plate 210 includes a second plate body 211 and a second hinge 220 screwed to the rear end of the second plate body 211. Both the adjusting member 3 and the second hinge 220 are sheet metal parts. The adjusting member 3 includes two symmetrically arranged support parts 3a extending forward and backward, and the two support parts 3a are connected by a transversely arranged connecting part 3b. The second hinge 220 includes hinge parts 221 formed by bending backward at both ends. The two support parts 3a of the adjusting member 3 are respectively attached to the side walls of the hinge parts 221 on both sides, and the two are connected together by bolts. Thus, the entire connecting rod slide mechanism is made of sheet metal parts, which has a low processing and manufacturing cost and is convenient for installation and disassembly.

[0040] Please refer to the attached document. Figure 4-6 In some embodiments of this application, the first support plate 110 is detachably connected to the backrest body 1a by screws, and the second support plate 210 is detachably connected to the lumbar support body 2a by screws. This not only makes the connection strength between the first support plate 110 and the backrest 1 and the second support plate 210 and the lumbar support 2 more reliable, but also makes the installation and disassembly operations more convenient.

[0041] In some embodiments of this application, the telescopic adjustment mechanism includes any one of a gas spring 4, a hydraulic rod, and an electric push rod. Mechanisms such as the gas spring 4, hydraulic rod, and electric push rod can not only extend and retract to adjust the length, thereby causing the adjusting member 3 to slide, but can also be fixed at any length, thus keeping the lumbar support 2 fixed, making adjustment operation simple.

[0042] Please refer to the attached document. Figure 4-5In some embodiments of this application, the telescopic adjustment mechanism is a gas spring 4, which is disposed on the backrest 1 or the lumbar support 2. When the lumbar support 2 rotates forward to the maximum angle, the rear end of the adjusting member 3 is located at the bottom end of the slide groove 101. The gas spring 4 applies a downward thrust to the adjusting member 3, so that one end of the adjusting member 3 always has the tendency to slide downward along the slide groove 101, and the other end of the adjusting member 3 pushes forward, thereby making the lumbar support 2 always have the tendency to rotate forward relative to the backrest 1.

[0043] In this embodiment, by setting the gas spring 4 to push the adjusting member 3 downward, the lumbar support 2 always has a tendency to rotate forward. When adjusting the tilt angle of the lumbar support 2, the lumbar support 2 can automatically rotate forward to fit the user's waist, without the need for manual adjustment by the user, making the adjustment operation relatively simple.

[0044] In this design, the piston rod on the upper side of the gas spring 4 is fixed to the first support plate 110 at the front end of the backrest 1, and the cylinder on the lower side of the gas spring 4 is located between two sliding support parts 121. Bolts pass through the support parts 3a on both sides of the adjusting member 3, the sliding grooves 101 on the sliding support parts 121, and the cylinder on the gas spring 4, hinged together. Of course, in other embodiments of this application, the gas spring 4 can also be connected to the rear side of the lumbar support 2.

[0045] Please refer to the attached document. Figure 4-5 In some embodiments of this application, the gas spring 4 is further provided with a wired control assembly, which includes an adjustment knob 401 and a pull cord 402. The adjustment knob 401 is located on one of the left and right sides of the backrest 1, and the adjustment knob 401 and the gas spring 4 are connected by the pull cord 402. The adjustment knob 401 is configured to adjust the pull cord 402 to squeeze or release the pin of the gas spring 4, thereby controlling the locking or unlocking of the gas spring 4. The user only needs to rotate the adjustment knob 401 on the side wall of the backrest 1 to control the locking or unlocking of the gas spring 4, thereby controlling the fixing or movement of the lumbar support 2, making the locking operation of the lumbar support 2 very convenient.

[0046] Please refer to the attached document. Figure 8 In some embodiments of this application, the gas spring 4 can also be a tension gas spring: the telescopic adjustment mechanism is a gas spring 4, which is disposed on the backrest 1 or the lumbar support 2; when the lumbar support 2 rotates forward to its maximum angle, the rear end of the adjusting member 3 is located at the top of the slide groove 101, and the gas spring 4 applies an upward pulling force to the adjusting member 3, so that one end of the adjusting member 3 always has a tendency to slide upward along the slide groove 101, and the other end of the adjusting member 3 pushes forward, thereby making the lumbar support 2 always have a tendency to rotate forward relative to the backrest 1. This allows the lumbar support 2 to automatically rotate forward to fit the user's waist when adjusting the tilt angle, without requiring manual adjustment by the user, making the adjustment operation relatively simple.

[0047] It should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used above to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means three or more.

[0048] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A lumbar support linkage adjustment device, characterized in that, The device includes a backrest (1) and a lumbar support (2) connected to the front side of the backrest (1). The upper end of the lumbar support (2) is hinged to the backrest (1), and the lower end of the lumbar support (2) is connected to the backrest (1) via a connecting rod and slide groove structure. The connecting rod and slide groove structure includes an adjusting member (3) and a slide groove (101). The slide groove (101) is formed along the length of one of the backrest (1) and the lumbar support (2). One end of the adjusting member (3) is slidably connected to the slide groove (101), and the other end is hinged to... The other of the backrest (1) and the lumbar support (2); when one end of the adjusting member (3) slides up and down along the slide groove (101), the lumbar support (2) is pushed or pulled by the adjusting member (3) and thus rotates back and forth relative to the backrest (1); a telescopic adjustment mechanism is also provided between the backrest (1) and the lumbar support (2), the telescopic adjustment mechanism is configured to adjust the adjusting member (3) to slide up and down and can fix the adjusting member (3) at any position on the slide groove (101).

2. The lumbar support linkage adjustment device according to claim 1, characterized in that, The backrest (1) includes a backrest body (1a) and a first support plate (110) connected to the front end of the backrest body (1a). The lumbar support (2) includes a lumbar support body (2a) and a second support plate (210) connected to the rear end of the lumbar support body (2a). The upper ends of the first support plate (110) and the second support plate (210) are hinged to each other. The slide groove (101) is opened on the first support plate (110) along the length direction.

3. The lumbar support linkage adjustment device according to claim 2, characterized in that, The upper ends of the first support plate (110) and the second support plate (210) are hinged to each other by a butterfly hinge (102).

4. The lumbar support linkage adjustment device according to claim 2, characterized in that, The first support plate (110) includes a first plate (111) connected to the backrest body (1a) and a first hinge (120) detachably connected to the front end of the first plate (111). The first hinge (120) is a sheet metal part. The first hinge (120) is bent forward to form a sliding support part (121). The slide groove (101) is opened in the sliding support part (121) along the length direction.

5. The lumbar support linkage adjustment device according to claim 2, characterized in that, The first support plate (110) is detachably connected to the backrest body (1a) by means of screws, and the second support plate (210) is detachably connected to the lumbar support body (2a) by means of screws.

6. The lumbar support linkage adjustment device according to claim 1, characterized in that, The telescopic adjustment mechanism is any one of a gas spring (4), a hydraulic rod, and an electric push rod.

7. The lumbar support linkage adjustment device according to claim 6, characterized in that, The telescopic adjustment mechanism is a gas spring (4), which is installed on the backrest (1) or the lumbar support (2). When the lumbar support (2) rotates forward to the maximum angle, the rear end of the adjustment member (3) is located at the bottom of the slide groove (101). The gas spring (4) applies a downward thrust to the adjustment member (3), so that one end of the adjustment member (3) always has the tendency to slide downward along the slide groove (101), and the other end of the adjustment member (3) pushes forward, so that the lumbar support (2) always has the tendency to rotate forward relative to the backrest (1).

8. The lumbar support linkage adjustment device according to claim 7, characterized in that, The gas spring (4) is provided with a wire control assembly, which includes an adjustment knob (401) and a pull cord (402). The adjustment knob (401) is located on one side of the left and right sides of the backrest (1). The adjustment knob (401) and the gas spring (4) are connected by the pull cord (402). The adjustment knob (401) is configured to adjust the pull cord (402) to squeeze or release the pin of the gas spring (4), thereby controlling the gas spring (4) to lock or unlock.

9. The lumbar support linkage adjustment device according to claim 6, characterized in that, The telescopic adjustment mechanism is a gas spring (4), which is installed on the backrest (1) or the lumbar support (2). When the lumbar support (2) rotates forward to the maximum angle, the rear end of the adjustment member (3) is located at the top of the slide groove (101). The gas spring (4) applies an upward pulling force to the adjustment member (3), so that one end of the adjustment member (3) always has the tendency to slide upward along the slide groove (101), and the other end of the adjustment member (3) pushes forward, so that the lumbar support (2) always has the tendency to rotate forward relative to the backrest (1).

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