CN221599578U - Waist rest depth adjusting mechanism - Google Patents

Abstract

The application discloses a lumbar support depth adjusting mechanism, which comprises: the waist rest body is rotationally connected to the back support; the support piece is arranged between the waist support body and the back support and comprises a matching part and an elastic part; the matching part is in sliding fit with the back support along the vertical direction, and the upper end of the elastic part is connected with the waist rest body; the gear adjusting mechanism comprises a gear piece arranged on one of the matching part or the back support, and one side of the gear piece is provided with a plurality of tooth grooves; the other one of the matching part or the back support is provided with an elastic clamping piece, and the elastic clamping piece is provided with a clamping head which can be clamped and matched with the tooth slot; when the waist rest body is adjusted to rotate forwards, the clamping head is sequentially clamped with the tooth grooves under the elastic action of the elastic clamping piece. According to the waist rest depth adjusting mechanism, a user can adjust gears only by rotating the waist rest body forwards and backwards, and the operation is simple and convenient; and the gear adjusting mechanism is hidden between the waist rest body and the back support, so that the whole seat is more attractive.

Description

Waist rest depth adjusting mechanism

Technical Field

The utility model relates to the technical field of seats in general, in particular to a lumbar support depth adjusting mechanism.

Background

Sub-health is always a living problem of people, wherein lumbar vertebra problems caused by sitting for a long time are frequent, and the chair is used as daily furniture for people to work and learn, so that under the long-time sitting office, the spine of a human body is naturally bent, particularly the bending at the lumbar vertebra is more important, the lumbar vertebra is easily bent outwards after sitting for a long time, and lumbar disc herniation and isosceles vertebra diseases are easily caused after the long time sitting.

It is known that the spine of a human body is S-shaped, so that a lumbar support is additionally arranged at the backrest part of the office chair to achieve the effect of reaching the lumbar, so that the natural bending part of the lumbar is supported, the spine is prevented from being bent outwards due to fatigue, and the lumbar health of office staff is ensured. However, in practical application, the requirements of different people on the waist rest are different; for a sedentary office worker, the waist rest is required to be more forward to be attached to the waist, so that the effect of pushing the waist is achieved; for a user sitting on the seat for relaxation and resting, the waist rest is required to relax a little, and obvious waist ejection effect is not required; the existing chairs with the lumbar support capable of being adjusted in the front-back depth can provide support for the waist of a user through the front-back adjustment of the lumbar support so as to meet different use requirements.

But the mode that current on-the-market waist leans on adjusting device adopts worm gear or act as go-between to adjust the waist to lean on, and the operation is wasted time and energy, often needs rotatory multiturn or great power operation just can carry out the front and back adjustment of waist leaning on, and the operation is very inconvenient, and user experience is poor. Moreover, the existing lumbar support adjustment achieves the effect of adjusting the top lumbar extent by locking the lumbar support at a certain position in front and back; the waist rest is in a complete locking state or can only mechanically rotate around a certain fulcrum for adjustment; this results in the lumbar support being too stiff for the user to use. Some existing lumbar supports can elastically deviate through arranging the lumbar supports, so that the self-adaptive adjusting function is realized; but this does not allow for adjustment of the front-to-back position of the lumbar support.

The prior patent discloses a lumbar depth adjusting mechanism (application number: CN 202111293424.8) comprising: the waist rest body is rotationally connected to the back support; the support component is longitudinally arranged between the waist support body and the back support and comprises a matching part and an elastic part; the support component correspondingly slides up and down along the back support in response to the rotation action of the waist support body; at least two positioning holes are arranged on the matching part; the adjusting component is arranged beside the supporting component; the adjusting component comprises a locking piece connected to the back support and a control handle for controlling the locking piece to transversely move; a locking pin which is in plug-in fit with the positioning hole is formed on the locking piece; when the locking pin is separated from the positioning hole, the waist rest body rotates back and forth and drives the supporting part to move up and down so as to adjust the initial position of the waist rest body; the locking pin is inserted into the positioning hole at the corresponding position to fix the initial position of the lumbar support body; when the waist support body is in different initial positions and receives a backward acting force, the elastic part is promoted to deform so as to elastically support the waist support body. Although the adjusting mechanism can adjust the front and back positions of the waist rest, a user cannot easily reach the adjusting spanner when sitting on the chair for adjustment, and the adjusting mechanism is inconvenient to adjust when leaving the chair; furthermore, the adjusting spanner sags at the side position behind the waist rest body, has a certain abrupt sense, and is unfavorable for the overall beauty and coordination.

Disclosure of Invention

In view of the foregoing drawbacks or shortcomings in the prior art, it is desirable to provide a lumbar support depth adjustment mechanism, in which a gear adjustment mechanism is disposed between a lumbar support body and a back support, and as the lumbar support body rotates back and forth, a support member slides up and down along the back support in response to rotation of the lumbar support body, and an elastic clamping member elastically deforms when moving, so as to drive a chuck to be sequentially clamped with each tooth slot to achieve gear adjustment of the lumbar support body. Therefore, a user can realize the gear adjustment of the lumbar support only by rotating the lumbar support body back and forth, other parts are not required to be operated or the user leaves the seat to adjust, and the operation is simple and convenient; and the gear adjusting mechanism is hidden between the waist rest body and the back support, so that the chair is attractive in appearance.

The application provides a lumbar support depth adjusting device, comprising:

The waist rest body is rotationally connected to the back support and can rotate back and forth around the back support;

The support piece is arranged between the waist support body and the back support and comprises a matching part at the bottom and a vertical elastic part with elasticity; the matching part is in sliding fit with the back support along the vertical direction, and the upper end of the elastic part is connected with the waist rest body; the support piece responds to the forward and backward rotation action of the waist support body and slides up and down along the back support;

the gear adjusting mechanism comprises a gear piece arranged on one of the matching part or the back support, and one side of the gear piece is provided with a plurality of tooth grooves; the other one of the matching part or the back support is provided with an elastic clamping piece, the elastic clamping piece is provided with a clamping head which can be clamped and matched with the tooth slot, and the elastic clamping piece always applies elastic force to the clamping head along the direction of clamping the tooth slot; when the waist rest body is adjusted to rotate forwards, the clamping head is sequentially clamped with the tooth grooves under the elastic action of the elastic clamping piece so as to realize gear adjustment of the waist rest body.

Further, a gear groove is concavely formed in the matching part, a gear piece is arranged in the gear groove, an annular interval is formed between the gear piece and the groove wall of the gear groove, the interval between one side of the gear piece with a tooth slot and the groove wall of the gear groove is a gear groove channel, and the interval between the back side of the gear piece with the tooth slot and the groove wall of the gear groove is a reset groove channel; when the waist rest body rotates forwards, the clamping head moves in the gear channel; when the lumbar support body rotates backwards, the clamping head moves in the reset channel.

Further, a longitudinal sliding support seat is arranged at the middle position of the lower part of the back support, and the matching part is in sliding fit with the sliding support seat.

Further, the back of the matching part is arc-shaped, the sliding supporting seat and the sliding contact surface of the matching part are correspondingly arranged to be arc-shaped surfaces, and the arc-shaped surfaces on the sliding supporting seat are bent forwards and upwards from bottom to top; so that the lumbar support body moves forward simultaneously in the process of moving up the support piece along the sliding support seat.

Further, a vertical elastic piece is arranged between the bottom end of the sliding support seat and the matching part, and the elastic piece enables the support piece to always have a downward moving trend relative to the back support, so that the lumbar support body always has a rearward rotating trend.

Further, the sliding support seat is connected with the matching part through a limiting assembly, and comprises a limiting protrusion arranged on one of the side wall of the sliding support seat and the matching part and a limiting groove arranged on the other one of the side wall of the sliding support seat and the matching part.

Further, the elastic part is a supporting spring piece with the matching part extending upwards, and the supporting spring piece is an arc body with the middle position protruding forwards.

Further, the upper end of the elastic part is matched with the waist rest body in a clamping way, the upper end of the waist rest body is provided with a bayonet, and the upper end of the elastic part is provided with elastic clamping tongues positioned at the left side and the right side; the upper end of the elastic part upwards penetrates out of the bayonet and enables the elastic clamping tongue to be clamped out of the bayonet, and the elastic clamping tongue limits the upper end of the elastic part to be fixed with the lumbar support body relatively in the vertical direction.

Further, the waist rest body is shaped like a Chinese character 'kou', and the two sides of the waist rest body are provided with rotary shafts in mirror images, and the rotary shafts are rotatably connected to the back support; and the rotating shaft is positioned at the lower part of the waist rest body.

Further, the gear piece comprises a tooth base arranged along the length direction of the matching part and a plurality of tooth columns arranged on the tooth base at intervals; tooth grooves are formed between two adjacent tooth columns; and the tooth columns uniformly extend obliquely downwards towards one side direction of the tooth base.

According to the waist rest depth adjusting device, the gear adjusting mechanism is arranged between the support piece and the back support, and when the seat is used, the clamping head on the elastic clamping piece is clamped into the tooth socket, so that the waist rest body and the back support are relatively fixed; when the waist support needs to be adjusted, along with the front and back rotation of the waist support body, the supporting piece responds to the rotation of the waist support body and slides up and down along the back support, the elastic clamping piece slides up and down relative to the gear piece, and the elastic clamping piece is clamped in the tooth groove due to the clamping head, so that the elastic clamping piece can elastically deform when moving, the clamping head is driven to slide out of the current tooth groove, and the clamping head slides into the previous tooth groove or the next tooth groove along the set direction of the tooth groove to realize the gear adjustment of the waist support body. Therefore, a user can realize the gear adjustment of the lumbar support only by rotating the lumbar support body back and forth, other parts are not required to be operated or the user leaves the seat to adjust, and the operation is simple and convenient; and the gear adjusting mechanism is hidden between the waist rest body and the back support, so that the chair is attractive in appearance.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the accompanying drawings in which:

Fig. 1 is a schematic side view of a lumbar support depth adjustment device according to an embodiment of the present application in an initial position;

Fig. 2 is a schematic side view of a lumbar support depth adjustment device according to an embodiment of the present application in a maximum position;

FIG. 3 is a schematic perspective view of a seat according to an embodiment of the present application;

FIG. 4 is a schematic perspective view of a support member according to an embodiment of the present application;

fig. 5 is a schematic view of a connection structure between a lumbar support depth adjusting device and a back support according to an embodiment of the present application;

FIG. 6 is a schematic view of a connection structure between a support member and a back support according to an embodiment of the present application;

Fig. 7 is a schematic view of an internal structure of a gear adjusting mechanism when the lumbar support depth adjusting device provided by the embodiment of the present application is located at a maximum position;

Fig. 8 is a schematic diagram of an internal structure of a gear adjusting mechanism when the lumbar support depth adjusting device provided by the embodiment of the present application is in an adjusting state;

Fig. 9 is a schematic view of an internal structure of a gear adjusting mechanism when the lumbar support depth adjusting device provided by the embodiment of the present application is at an initial position;

Fig. 10 is a schematic view of an internal structure of a gear adjusting mechanism when the lumbar support depth adjusting device provided by the embodiment of the present application is in a reset state;

Fig. 11 is a schematic view of a connection structure between a support member and a lumbar support body according to an embodiment of the present application.

The reference numerals are as follows: 1-lumbar support body, 2-back support, 21-front cover plate, 22-back support, 100-support, 110-mating part, 111-gear slot, 112-gear slot, 113-reset slot, 114-limit slot, 115-second clamping hook, 120-elastic part, 121-elastic clamping tongue, 130-bayonet, 140-rotating shaft, 141-rotating seat, 150-side support section, 200-gear piece, 210-tooth socket, 201-tooth base, 202-tooth column, 300-elastic clamping piece, 310-clamping head, 400-sliding support seat, 401-first clamping hook, 410-limit bulge and 500-elastic piece.

Description of the embodiments

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be noted that, for convenience of description, only the portions related to the utility model are shown in the drawings.

Referring to fig. 1-11, an embodiment of the present application provides a lumbar support depth adjustment device, including:

The waist rest body 1 is rotatably connected with the back support 2, and the waist rest body 1 can rotate around the back support 2 back and forth;

The support piece 100 is arranged between the lumbar support body 1 and the back bracket 2, and the support piece 100 comprises a matching part 110 at the bottom and a vertical elastic part 120 with elasticity; the matching part 110 is matched with the back support 2 in a sliding way along the vertical direction, and the upper end of the elastic part 120 is connected with the lumbar support body 1; the support 100 slides up and down along the back bracket 2 in response to the back-and-forth rotation of the lumbar support body 1;

The gear adjusting mechanism comprises a gear piece 200 arranged on one of the matching part 110 or the back bracket 2, and one side of the gear piece 200 is provided with a plurality of tooth sockets 210; the other of the matching part 100 or the back bracket 2 is provided with an elastic clamping piece 300, the elastic clamping piece 300 is provided with a clamping head 310 which can be clamped and matched with the tooth slot 210, and the elastic clamping piece 300 always applies elastic force to the clamping head 310 along the direction of clamping into the tooth slot 210; when the lumbar support body 1 is adjusted to rotate forwards, the clamping head 310 is sequentially clamped with the tooth grooves 210 under the elastic action of the elastic clamping piece 300 so as to realize gear adjustment of the lumbar support body 1.

In this embodiment, by providing a gear adjusting mechanism between the support 100 and the back support 2, when the seat is used, the chuck 310 on the elastic chuck 300 is clamped into the tooth slot 210, so that the lumbar support body 1 and the back support 2 are relatively fixed; when the lumbar support needs to be adjusted, along with the front-back rotation of the lumbar support body 1, the support member 100 responds to the rotation of the lumbar support body 1 and slides up and down along the back support 2, so that the elastic clamping member 300 slides up and down relative to the gear member 200, and the clamping head 310 is clamped in the tooth groove 210, so that the elastic clamping member 300 is elastically deformed when moving, thereby driving the clamping head 310 to slide out of the current tooth groove 210 and slide into the previous tooth groove 210 or the next tooth groove 210 along the opening direction of the tooth groove 210, and the gear adjustment of the lumbar support body 1 is realized. Therefore, a user can realize the gear adjustment of the lumbar support only by rotating the lumbar support body 1 back and forth, other parts are not required to be operated or the user leaves the seat to adjust, and the operation is simple and convenient; in addition, the gear adjusting mechanism is hidden between the waist rest body 1 and the back support 2, does not have abrupt sense, and enables the whole chair to be more attractive.

The elastic clamping piece 300 is in a Z-shaped rod-shaped structure, the protruding end part of the top of the elastic clamping piece 300 penetrates through and is fixed on a side panel of the back support 2, which is close to the lumbar support body 1, the protruding end part of the bottom of the elastic clamping piece 300 is a clamping head 310, and the elastic clamping piece 300 is made of an elastic material, so that when the elastic clamping piece 300 is stressed to deform, the clamping head 310 at the bottom swings left and right along with the deformation, and the clamping head 310 is driven to slide left and right in the tooth groove 210 and switch the tooth groove 210, so that gear adjustment is realized.

In some embodiments of the present application, a gear groove 111 is concavely disposed on the mating portion 110, a gear piece 200 is disposed on the gear groove 111, an annular space is formed between the gear piece 200 and a groove wall of the gear groove 111, a space between a side of the gear piece 200 having a tooth slot 210 and the groove wall of the gear groove 111 is a gear groove 112, and a space between a back side of the gear piece 200 having the tooth slot 210 and the groove wall of the gear groove 111 is a reset groove 113; when the lumbar support body 1 rotates forwards, the clamping head 310 moves in the gear channel 112; when the lumbar support body 1 rotates backward, the chuck 310 moves in the reset channel 113. Therefore, in the gear adjusting process, the clamping head 310 moves in the gear channel 112, so that the offset is not easy to generate, and the gear adjusting process is more stable; meanwhile, when the gear is adjusted to the highest position, the clamping head 310 can be easily returned to the lowest position through the reset channel 113, so that the gear reset operation is more convenient.

In some embodiments of the present application, a longitudinal sliding support 400 is provided at a middle position of the lower portion of the back support 2, and the engaging portion 110 is slidably engaged with the sliding support 400. By connecting the support 100 and the back bracket 2 in a sliding fit manner with the fitting portion 100 and the sliding support seat 400, the stability of the connection therebetween is ensured.

Wherein, the back bracket 2 comprises a front cover plate 21 and a rear bracket 22 which are connected in the horizontal direction, one surface of the front cover plate 21 protrudes towards the lumbar support body 1 to form a sliding support seat 400, and the protruding end part on the top of the elastic clamping piece 300 passes through and is fixed at the position higher than the sliding support seat 400 on the rear bracket 22, so that the clamping head 310 at the bottom of the elastic clamping piece 300 can extend into the sliding support seat 400 and be contacted with the gear piece 200.

In some embodiments of the present application, the back surface of the mating portion 110 is arc-shaped, the sliding support seat 400 and the sliding contact surface of the mating portion 110 are correspondingly provided as arc-shaped surfaces, and the arc-shaped surfaces on the sliding support seat 400 are curved forward and upward from bottom to top; so that the lumbar support body 1 is simultaneously moved forward during the upward movement of the support 100 along the sliding support seat 400. Thereby, the movement direction between the fitting portion 110 and the slide support 400 in the vertical direction is converted into the rotation direction of the lumbar support body 1 about the rotation shaft 140.

In some embodiments of the present application, a vertical elastic member 500 is disposed between the bottom end of the sliding support seat 400 and the mating portion 110, and the elastic member 500 makes the support member 100 always have a downward movement tendency relative to the back support 2, so that the lumbar support body 1 always has a rearward rotation tendency. In the use process of the seat, the matching portion 110 always has a downward movement trend relative to the elastic clamping member 300, so that the clamping head 310 always clings to the tooth slot 210, and the stability of the connection between the two is ensured.

The bottom end of the sliding support 400 is provided with a first hook 401, the bottom end of the mating portion 110 is provided with a second hook 115, one end of the elastic member 500 is hung on the first hook 401, and the other end is hung on the second hook 115.

The elastic member 500 may be a spring, rubber, elastic sheet, or the like. Preferably, in the embodiment of the present application, the elastic member 500 is a spring, which not only has better elasticity and ductility, but also has better structural stability and is not easy to damage.

In some embodiments of the present application, the sliding support 400 is connected to the mating portion 110 through a limiting component, which includes a limiting protrusion 410 disposed on one of the side wall of the sliding support 400 and the mating portion 110, and a limiting groove 114 disposed on the other of the side wall of the sliding support 400 and the mating portion 110. Therefore, the matching part 110 and the sliding support seat 400 are restrained by the limiting assembly during relative sliding, and the stability of connection between the two is improved.

Preferably, the two sides of the gear slot 111 on the mating portion 110 are provided with a limiting slot 114, and two limiting protrusions 410 are disposed at opposite positions of the side wall of the sliding support 400, so as to further improve the stability of the connection therebetween.

In some embodiments of the present application, the elastic portion 120 is a supporting spring protruding upward from the mating portion 110, and the supporting spring is an arc protruding forward from the middle position. When the lumbar support body 1 rotates backwards and presses the supporting spring, the supporting spring will deform to a certain extent in the vertical direction, so that the engaging portion 110 has a downward movement tendency.

In some embodiments of the present application, the upper end of the elastic portion 120 is in snap fit with the lumbar support body 1, the upper end of the lumbar support body 1 is provided with a bayonet 130, and the upper end of the elastic portion 120 is provided with elastic clamping tongues 121 located on the left and right sides; the upper end of the elastic part 120 passes through the bayonet 130 upwards and the elastic clamping tongue 121 is clamped outside the bayonet 130, and the elastic clamping tongue 121 limits the upper end of the elastic part 120 and the lumbar support body 1 to be relatively fixed in the vertical direction. The elastic part 120 is connected with the lumbar support body 1 in a clamping fit manner, so that the assembly and disassembly between the elastic part and the lumbar support body are more convenient.

In some embodiments of the present application, the lumbar support body 1 is shaped like a Chinese character 'kou', and two mirror images on two sides of the lumbar support body 1 are provided with rotating shafts 140, and the rotating shafts 140 are rotatably connected to the back support 2; and the rotation shaft 140 is positioned at the lower portion of the lumbar support body 1. Such that the lumbar support body 1 is eccentrically rotated such that the rearward rotation of the lumbar support body 1 can apply a downward-slanted force to the support member 100, directly acting on the support member 100 to move downward. And the rotation range of the upper part of the waist support body 1 is larger, so that the waist supporting effect of the waist support body 1 is more obvious.

The lumbar support body 1 comprises side support sections 150 positioned at two sides, and a rotating shaft 140 horizontally extending towards the center of the lumbar support body 1 is arranged at the lower part of the side support sections 150; the two sides of the back support 2 are correspondingly provided with rotating seats 141, and the rotating shaft 140 is rotatably connected to the rotating seats 141 so that the lumbar support body 1 can rotate around the back support 2 back and forth. And, the side support section 150 is the arc body that upper portion forward protrusion for the waist is leaned on body 1 to laminate the top waist of user's waist with the help of this cambered surface, accords with ergonomic more, promotes the protection effect to user's waist.

In some embodiments of the present application, the gear member 200 includes a tooth base 201 disposed along a length of the mating portion 110 and a plurality of tooth posts 202 spaced apart on the tooth base 201; tooth slots 210 are formed between two adjacent tooth columns 202; and the tooth post 202 is uniformly extended obliquely downward toward one side of the tooth base 201. The tooth post 202 extends downwards obliquely towards one side of the tooth base 201, so that when the back of a user is propped against the lumbar support body 1, the matching part 110 moves downwards relative to the elastic clamping piece 300, the clamping head 310 is clamped at a position which is concaved upwards obliquely in the tooth groove 210, and the unstable connection between the lumbar support body 1 and the back support 2 caused by left and right shaking when the clamping head 310 is clamped in the tooth groove 210 is avoided, and the lumbar jacking effect of the lumbar support body 1 is influenced; meanwhile, when the gear is adjusted, the matching part 110 moves upwards relative to the elastic clamping piece 300, and the clamping head 310 can slide out obliquely downwards along the oblique direction of the tooth slot 210, so that the gear adjusting operation is easier.

It is to be understood that the above references to the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., are for convenience in describing the present utility model and simplifying the description only, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the present utility model. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, unless otherwise indicated, the meaning of "plurality" is three or more.

The above description is only illustrative of the preferred embodiments of the present utility model and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the utility model referred to in the present utility model is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept. Such as the above-mentioned features and the technical features disclosed in the present utility model (but not limited to) having similar functions are replaced with each other.

Claims (10)

1. A lumbar depth adjustment mechanism, comprising:

The waist rest body is rotationally connected with the back support and can rotate around the back support back and forth;

The support piece is arranged between the waist support body and the back support and comprises a matching part at the bottom and a vertical elastic part with elasticity; the matching part is in sliding fit with the back support along the vertical direction, and the upper end of the elastic part is connected with the lumbar support body; the support piece responds to the forward and backward rotation action of the waist rest body and slides up and down along the back support;

The gear adjusting mechanism comprises a gear piece arranged on one of the matching part or the back support, and one side of the gear piece is provided with a plurality of tooth grooves; the elastic clamping piece is arranged on the other one of the matching part and the back support, and is provided with a clamping head which can be clamped and matched with the tooth slot, and the elastic clamping piece always applies elastic force to the clamping head along the direction of clamping into the tooth slot; when the waist rest body is adjusted to rotate forwards, the clamping head is sequentially clamped with the tooth grooves under the action of the elastic force of the elastic clamping piece so as to realize gear adjustment of the waist rest body.

2. The lumbar depth adjustment mechanism according to claim 1, wherein a gear groove is concavely formed in the mating portion, the gear piece is disposed in the gear groove, an annular space is formed between the gear piece and a groove wall of the gear groove, a space between one side of the gear piece with the tooth slot and the groove wall of the gear groove is a gear groove channel, and a space between a back side of the gear piece with the tooth slot and the groove wall of the gear groove is a reset channel; when the lumbar support body rotates forwards, the clamping head moves in the gear channel; when the lumbar support body rotates backwards, the clamping head moves in the reset channel.

3. The lumbar support depth adjustment mechanism of claim 1, wherein a longitudinal sliding support seat is provided at a central position of the lower portion of the back support, and the engagement portion is slidably engaged with the sliding support seat.

4. The lumbar support depth adjustment mechanism according to claim 3, wherein the back surface of the mating portion is curved, the sliding support seat and the sliding contact surface of the mating portion are provided with curved surfaces, and the curved surfaces on the sliding support seat are curved forward and upward from bottom to top; so that the lumbar support body moves forward simultaneously in the process of moving up the support piece along the sliding support seat.

5. A lumbar depth adjustment mechanism according to claim 3, wherein a vertical elastic member is provided between the bottom end of the sliding support base and the mating portion, the elastic member enabling the support member to always have a tendency to move downward relative to the back support, and enabling the lumbar support body to always have a tendency to rotate rearward.

6. The lumbar support depth adjustment mechanism of claim 3, wherein the sliding support and the mating portion are connected by a limiting assembly comprising a limiting protrusion disposed on one of the sliding support side wall and the mating portion, and a limiting groove disposed on the other of the sliding support side wall and the mating portion.

7. The lumbar support depth adjustment mechanism of claim 1, wherein the elastic portion is a supporting spring extending upward from the mating portion, and the supporting spring is an arc protruding forward from a middle position.

8. The lumbar support depth adjustment mechanism according to claim 1, wherein the upper end of the elastic portion is in clamping fit with the lumbar support body, a bayonet is arranged at the upper end of the lumbar support body, and elastic clamping tongues positioned at the left side and the right side are arranged at the upper end of the elastic portion; the upper end of the elastic part upwards penetrates out of the bayonet and enables the elastic clamping tongue to be clamped out of the bayonet, and the elastic clamping tongue limits the upper end of the elastic part and the waist rest body to be relatively fixed in the vertical direction.

9. The lumbar support depth adjustment mechanism according to claim 1, wherein the lumbar support body is shaped like a Chinese character 'kou', and two mirror images of two sides of the lumbar support body are provided with rotating shafts which are rotatably connected to the back support; and the rotating shaft is positioned at the lower part of the waist rest body.

10. The lumbar depth adjustment mechanism of claim 1, wherein the gear piece includes a tooth base portion disposed along a length of the mating portion and a plurality of tooth posts spaced apart on the tooth base portion; the tooth grooves are formed between two adjacent tooth columns; and the tooth post is uniformly arranged in an extending way obliquely downwards towards one side direction of the tooth base.