CN218105347U - Back of chair supports adjusting device and seat - Google Patents

Abstract

The utility model provides a chair back support adjusting device and a chair, which comprises a fixed seat and a back connecting piece; the sliding positioning mechanism comprises a positioning chute arranged on the back connecting piece and a clamping piece arranged in the fixed seat; in a use state, the clamping piece and the positioning chute are clamped and matched up and down to limit the backward movement of the back connecting piece; under the adjusting state, the back connecting piece moves forwards, and the positioning chute and the clamping piece are extruded to enable the clamping piece to elastically contract so as to exit the positioning chute; the reset mechanism comprises a reset pressure plate which is arranged in the fixed seat in a sliding way, and a front push block and a rear push block which are respectively arranged at the front end and the rear end of the back connecting piece; when the back connecting piece moves forwards to the rear push block to push the reset pressure plate to move forwards so as to act on the clamping piece to keep the elastic contraction state all the time, the back connecting piece can reset backwards; when the back connecting piece is reset backwards until the front pushing block pushes the reset pressing plate to be staggered with the clamping piece, the clamping piece is elastically clamped in the positioning chute again; the seat and back connector are configured to connect to the seat back.

Description

Back of chair supports adjusting device and seat

Technical Field

The utility model relates to a thing to sit on field, in particular to back of chair supports adjusting device and seat.

Background

The children chair is an essential tool for middle and small friends in family to relax, read and write at ordinary times, and generally has the functions of stable structure, comfortable riding, convenient movement and the like. Furthermore, the structure of current children's chair all installs on a fore-and-aft chair pole for seat support and back of the chair usually for this chair pole can be followed to seat support and back of the chair and carry out lift adjustment, can adjust seat support, back of the chair height according to child's height or user demand. However, most of the existing children chairs can only realize the height adjustment of the chair seat and the chair back basically, and can not adjust the front and back positions of the chair seat and the chair back, particularly the front and back positions of the chair back.

In the actual use process of the chair, different people have different sitting postures and habits, or children have different requirements on the chair back when using the chair, for example, children with a little higher height generally need to lean backwards a little, so that the children can have more space on the chair plate, children with a little lower height generally need to lean backwards the chair back because of smaller body shape, the chair back is too back, when sitting on the chair and leaning against the chair back, the lower legs can not be bent naturally, and the sitting is uncomfortable. Moreover, the requirements for the chair back of the chair are different at different moments, for example, when the chair back is relaxed, the chair back is usually liked to be back, and more space is reserved on the seat plate, so that the chair can sit forward a little bit slightly and then lean against the chair back, the back has a larger inclination angle, and the chair can be relaxed when sitting, so that the effect of eliminating fatigue is achieved; when the user needs to concentrate on the mental study or the writing operation, the gravity center can be deviated forwards, the back cannot lean against the chair back, the back muscle can be tired after a long time, and the child can also become tired.

Aiming at the situations, a child chair with a chair back capable of being adjusted forwards and backwards is needed, so that the child chair can be adjusted at any time when the chair back is required to be at different positions, the back is protected better, and the body is healthier; and the adjustment operation is very simple and easy, and is convenient for children to operate by themselves.

Disclosure of Invention

The utility model aims to overcome the defects in the prior art and provide a chair back support adjusting device; the back connecting piece can move forwards relative to the fixed seat for adjustment through the sliding positioning mechanism and is provided with a plurality of adjusting gears; the back connecting piece can only move forwards relative to the fixed seat and can not move backwards relative to the fixed seat; the back connecting piece is used for connecting the chair back, so that a user can stably lean backwards on the chair back; the reset mechanism enables the back connecting piece to move forwards to push the reset pressure plate and then to move backwards for resetting; the structure design is ingenious.

The chair is further provided, so that the chair back of the chair can be adjusted very conveniently and quickly, and the chair back can be positioned to different adjusting positions only by acting on the forward movement of the chair back; when the chair back moves forwards to the maximum distance, the chair back is reset backwards; so that the chair back can be adjusted back and forth in a reciprocating way.

The technical scheme of the utility model is realized like this:

a back support adjustment device, comprising: a fixed seat and a back connecting piece; the back connecting piece is arranged along the front-back direction and is in sliding fit in the fixed seat, and the back connecting piece can slide back and forth relative to the fixed seat; the sliding positioning mechanism comprises positioning chutes which are arranged on the back connecting piece at intervals along the front-back direction and clamping pieces which are arranged in the fixed seat and can elastically stretch along the longitudinal direction; the back connecting piece is provided with a use state and an adjusting state, and in the use state, the clamping piece is clamped and matched with the positioning chute up and down to limit the back connecting piece to move backwards; in an adjusting state, the back connecting piece moves forwards, a first inclined plane is arranged in the positioning chute, and a second inclined plane is correspondingly arranged at the upper end of the clamping piece; the first inclined plane and the second inclined plane are mutually extruded to enable the clamping piece to elastically contract so as to exit the positioning chute; the clamping piece always has the tendency of being clamped with the positioning chute; the resetting mechanism comprises a resetting pressure plate arranged in the fixed seat in a sliding manner, and a front push block and a rear push block which can push the resetting pressure plate to move and are respectively arranged at the front end and the rear end of the back connecting piece; when the back connecting piece moves forwards to the rear push block to push the reset pressure plate to move forwards so as to act that the clamping piece always keeps an elastic contraction state, the back connecting piece can reset backwards; when the back connecting piece is reset backwards to the front pushing block to push the reset pressing plate to move backwards and to be staggered with the clamping piece, the clamping piece is elastically reset and clamped in the positioning chute again.

Preferably, the positioning chute is arranged on the bottom surface of the back connecting piece, and the clamping piece comprises clamping convex blocks which are positioned in the middle and protrude upwards and side convex blocks which are positioned on two sides respectively and sink relative to the clamping convex blocks; the clamping convex block is configured to be in clamping fit with the positioning chute, and the second inclined plane is formed on the clamping convex block; the lateral part protruding block is configured to be capable of being in up-and-down extrusion fit with the reset pressing plate so that the clamping piece can be always kept in an elastic contraction state. Then the joint spare can enough play the effect of location joint with the location chute, can also cooperate in order to keep the elastic shrinkage state with the clamp plate that resets.

Preferably, the side section of the positioning chute is in a right trapezoid shape; the first inclined plane is a groove wall on one side of the positioning chute, and the first inclined plane inclines towards the front upper part from back to front; the side cross-sectional shape of joint lug is right trapezoid shape correspondingly, and when back of the body connecting piece slided forward, first inclined plane and second inclined plane extrusion fit shrunk downwards with effect joint spare. Then, after the clamping lug is clamped and matched with the positioning chute, the back connecting piece can only move forwards relative to the fixed seat and cannot move backwards relative to the fixed seat; the back link is used to connect the back of the chair so that the user can rest stably backwards on the back of the chair.

Preferably, two sides of the front end of the reset pressure plate are respectively provided with a pressure block protruding forwards; the rear push block can abut against the rear end of the reset pressure plate and push the reset pressure plate to move forwards so that the press block is pressed at the upper end of the side convex block. Then the pressing block is pressed on the convex block at the side part, and the elastic piece can be limited to be upwards bounced.

Preferably, the fixed seat is concavely provided with a caulking groove, the reset pressing plate is embedded in the caulking groove, and the reset pressing plate can move back and forth in the caulking groove; the elastic piece is arranged in the middle of the front end of the caulking groove; elastic strips capable of elastically deforming along the left and right directions are respectively arranged on the left side and the right side of the reset pressure plate, and clamping heads are arranged at the end parts of the elastic strips; the lateral walls of the left side and the right side of the caulking groove are respectively and correspondingly provided with a groove which is spaced from the front side to the rear side, and the clamping head can be clamped and matched with the groove. Then the reset pressure plate can slide in the caulking groove, and the clamping heads are respectively clamped in the grooves at different positions; therefore, the reset pressure plate cannot easily slide, and the structure is stable because acting force is applied to the reset pressure plate.

Preferably, the front push blocks are arranged on two sides of the front end of the back connecting piece in a mirror image manner; the rear push blocks are arranged on two sides of the rear end of the back connecting piece in a mirror image mode; an avoidance sliding groove for avoiding the front push block and the rear push block is correspondingly and concavely arranged in the fixed seat along the front and rear directions; and the avoiding sliding groove is communicated with the front and the back of the caulking groove. The front push block and the rear push block can not interfere with the fixed seat and can directly push the reset pressing plate.

Preferably, a longitudinal movable sinking groove for accommodating the clamping piece is formed in the front end of the fixing seat, and the clamping piece is arranged in the movable sinking groove; and a longitudinal spring acting on the clamping piece is arranged between the clamping piece and the movable sinking groove, and the spring is configured to ensure that the clamping piece always has the tendency of being clamped with the positioning inclined groove. Make the relative fixing base of back of the body connecting piece move the in-process forward, the joint spare can constantly take place elastic expansion in order to cooperate with the location chute joint of different positions in proper order for it is obvious to adjust the gear sense.

Preferably, the device also comprises an elastic piece arranged between the fixed seat and the back connecting piece; the elastic piece is arranged along the front-back direction, and the front end and the back end of the elastic piece are respectively connected with the back connection and the fixed seat; the elastic member moves forwards in response to the back connecting member and is elastically deformed correspondingly to provide the elastic force for the back connecting member to reset backwards. When the back connecting piece is reset backwards, the back connecting piece can reset automatically.

Preferably, the elastic member is an elastic band or a rubber band. Simple structure and low cost.

A chair comprises a chair back, a support positioned at the back of the chair back and a chair back support adjusting device; the support is provided with a longitudinal support rod positioned at the rear end; the fixing seat is arranged at the upper end of the supporting rod, and the front end of the back connecting piece is connected with the chair back.

Adopted above-mentioned technical scheme the utility model discloses a design departure point, theory and beneficial effect are:

the utility model discloses a chair back support adjusting device, through setting up the slip positioning mechanism between back of the body connecting piece and fixing base, make the back of the body connecting piece can only move forward and adjust relative to the fixing base; when the back connecting piece moves to any position, the clamping piece is clamped and matched with the positioning chute to limit the back connecting piece to move backwards, so that the backstop effect is achieved; and the back connecting piece is used for connecting the chair back, so that a user can stably lean backwards on the chair back in any adjusting position. By arranging the reset pressing plate, when the back connecting piece moves forwards for the maximum distance, the back pushing block of the back connecting piece can push the reset pressing plate to move forwards, the pressing block of the reset pressing plate presses on the side protruding block of the clamping piece, so that the clamping piece is kept in a shrinkage state, and then the back connecting piece can move backwards for resetting; after the back connecting piece is reset backwards, the front push block at the front end of the back connecting piece can push the reset pressure plate to move backwards, so that the clamping piece can be clamped in the positioning chute again; the back connecting piece can carry out reciprocating back and forth movement adjustment relative to the fixed seat; then the adjusting device is applied to the seat, so that the adjustment of the chair back is very easy and simple, the chair back can be sequentially positioned at different gears only by grasping the forward movement of the chair back, and the chair back can be moved backwards and reset after moving forwards for the maximum distance.

Secondly, an elastic piece is arranged and can provide elasticity to enable the back connecting piece to reset backwards quickly; so that the adjustment operation is simpler.

Moreover, the structure is arranged between the back connecting piece and the fixed seat and can not be exposed outside; so that the whole structure of the device is simple and beautiful.

Drawings

Fig. 1 is a schematic perspective view of a back connecting member and a fixing base according to an embodiment of the present invention;

fig. 2 is a schematic perspective view of the back connecting member and the bottom of the fixing base according to the embodiment of the present invention;

fig. 3 is an exploded view of the embodiment of the present invention in which the back connecting member is connected to the fixing base;

fig. 4 is a schematic perspective view of the interior of the fixing base in the embodiment of the present invention;

fig. 5 is a schematic perspective view of the elastic member engaged with the positioning chute according to the embodiment of the present invention;

fig. 6 is a side view of the back link moving forward to a maximum position in an embodiment of the present invention;

fig. 7 is a side view of another section of the back link moving forward to a maximum position in an embodiment of the invention;

fig. 8 is a side view of the embodiment of the present invention in which the back link is restored to the rear;

fig. 9 is a side view of another cross-section of the back connector in an embodiment of the present invention, returning to the back position;

fig. 10 is a schematic perspective view of a seat according to an embodiment of the present invention.

The figures are numbered: a fixed seat 1; a back connector 2; a positioning chute 3; a first slope 3a; a clamping piece 4; the convex block 4a is clamped; side projections 4b; a second slope 401; a movable sink tank 5; a spring 6; a reset pressure plate 7; pressing blocks 701; a caulking groove 8; a front push block 9; a rear push block 10; an avoidance chute 11; an elastic buckle 12; a chuck 12a; a recess 13; an elastic member 14; a receiving groove 15; a strut 16; a chair back A; and a support B.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

In the description of the present invention, the term "at least one" means one or more unless explicitly defined otherwise. The terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The present embodiment relates to reference orientations of components such as front, rear, etc., which are described in a normal use state in which a user is seated behind a seat.

The utility model discloses a specific embodiment as follows:

as shown in fig. 1-9, the chair back supporting and adjusting device provided by the present invention comprises a fixing seat 1 and a back connecting member 2; the back connecting piece 2 is arranged along the front-back direction, and the front end of the back connecting piece 2 is configured to be connected with a chair back; the back connecting piece 2 is in sliding fit in the fixed seat 1, so that the back connecting piece 2 can slide back and forth relative to the fixed seat 1, and the chair back can be adjusted back and forth.

As shown in fig. 2-6, the back connecting member 2 is slidably inserted into the fixing base 1, a sliding positioning mechanism is disposed between the back connecting member 2 and the fixing base 2, the sliding positioning mechanism includes positioning chutes 3 disposed on the back connecting member 2 at intervals along the front-back direction and clamping members 4 disposed in the fixing base 1 and capable of elastically stretching in the longitudinal direction, and the clamping members 4 can be clamped in the positioning chutes 3 upwards; the method specifically comprises the following steps: the location chute 3 set up on the bottom surface of back of the body connecting piece 2, the side cross-section of this location chute 3 is right trapezoid shape, the inner wall of location chute 3 has first inclined plane 3a, by back-to-front, this first inclined plane 3a inclines towards the upper place. A longitudinal movable sinking groove 5 for accommodating a clamping piece 4 is formed in the fixed seat 1, and the clamping piece 4 is arranged in the movable sinking groove 5; a spring 6 acting on the clamping piece 4 in the longitudinal direction is arranged between the bottom of the clamping piece 4 and the movable sinking groove 5, and the upper end of the clamping piece 4 is provided with a clamping convex block 4a which protrudes upwards and can be clamped with the positioning chute 3; the spring 6 is configured such that the latching projection 4a always has a tendency to latch upwards with the positioning chute 3. The lateral section of the clamping convex block 4a is also in a right-angled trapezoid shape, so that the clamping convex block 4a can be completely clamped in the positioning chute 3; the clamping convex block 4a is correspondingly provided with a second inclined surface 401 which can be matched with the first inclined surface 3a; as shown in fig. 5, when the back connector 2 is in a use state at any position, that is, the clamping protrusion 4a is clamped with the positioning chute 3 up and down, and the first inclined surface 3a is tightly attached to the second inclined surface 401; the clamping convex block 4a and the positioning chute 3 can limit the backward movement of the back connecting piece 2 relative to the fixed seat 1, and then a user can stably lean backwards on the chair back. The clamping convex block 4a and the positioning chute 3 are configured to enable the back connecting piece 2 to move forwards and adjust relative to the fixed seat 1, when the back connecting piece 2 needs to move correspondingly and adjust, only a forward acting force needs to be applied to the back connecting piece 2 directly, so that the first inclined plane 3a and the second inclined plane 401 are extruded mutually, and the acting force acts on the clamping piece 4 to move downwards to enable the clamping convex block 4a to exit the positioning chute 3 downwards; the spring 6 is compressed accordingly to provide an elastic force to return the snap 4 upward again. Then, in the process that the back connecting piece 2 moves forwards relative to the fixed seat 1, the clamping piece 4 can continuously elastically stretch and contract to be clamped and matched with the positioning chutes 3 at different positions in sequence, so that gear adjusting feeling is obvious; the clamping piece 4 is clamped with the positioning chute 3 at any position to limit the backward movement of the back connecting piece 2, so that the backstop effect is achieved; so that the adjustment of the back connector 2 is very convenient.

As shown in fig. 3-8, a reset mechanism is further arranged between the back connecting piece 2 and the fixing seat 1, the reset mechanism enables the back connecting piece 2 to reset backwards after moving forwards, the reset mechanism comprises a reset pressing plate 7 which is arranged in the fixing seat 1 and can be in up-and-down press fit with the clamping piece 4, an embedding groove 8 is concavely arranged in the fixing seat 1, the reset pressing plate 7 is embedded in the embedding groove 8, and the reset pressing plate 7 can move forwards and backwards in the embedding groove 8; as shown in fig. 3 and 4, the left and right sides of the reset pressure plate 7 are respectively provided with an elastic strip 12 capable of elastically deforming in the left and right directions, and the end of the elastic strip 12 is provided with a chuck 12a; the side walls of the left side and the right side of the caulking groove 8 are respectively and correspondingly provided with a groove 13 with a front space and a rear space, and the clamping head 12a can be clamped and matched with the groove 13; then the reset pressure plate 7 can slide in the caulking groove 8, and the clamping heads 12a are respectively clamped in the grooves 13 at different positions; the reset pressure plate 7 is prevented from shifting itself. The movable sinking groove 5 is arranged in the middle of the front end of the caulking groove 8, so that the clamping piece 4 is positioned at the front end of the caulking groove 8; the clamping piece 4 further comprises side bumps 4b which are respectively positioned at the left side and the right side and are sunken relative to the clamping bumps 4a, and the height of each side bump 4b is lower than that of each clamping bump 4a; correspondingly, pressing blocks 701 protruding forwards are respectively arranged on two sides of the front end of the reset pressing plate 7. The front end and the rear end of the bottom surface of the back connecting piece 2 are respectively provided with a front push block 9 and a rear push block 10 which can push the reset pressure plate 7 to move and protrude downwards; the front push blocks 9 are arranged on two sides of the front end of the back connecting piece 2 in a mirror image mode, and the rear push blocks 10 are arranged on two sides of the rear end of the back connecting piece 2 in a mirror image mode; an avoidance chute 11 for avoiding the front push block 9 and the rear push block 10 is correspondingly arranged in the fixed seat 1 along the front-back direction.

Then, as shown in fig. 5-7, when the back connector 2 slides forward to the maximum distance, the clamping protrusion 4a abuts against the bottom surface of the rear end of the back connector 2, so that the clamping connector 4 is in a contracted state, and the upper end surfaces of the side protrusions 4b at the two sides of the clamping connector 4 are lower than the bottom wall of the caulking groove 8; the rear push block 10 will extrude the rear end of the reset pressure plate 7 to move the reset pressure plate 7 forward, so that the press blocks 701 at the two sides of the reset pressure plate 7 will press the upper ends of the side bumps 4b at the two sides of the clamping piece 4; therefore, the reset pressing block 7 can limit the clamping piece 4 to protrude upwards, and the clamping heads 12a on the two sides of the reset pressing block 7 can be clamped with the grooves 13, so that the reset pressing plate 7 is kept at the position; so that the snap-in 4 will remain in this contracted state; then can act on back of the body connecting piece 2 this moment and remove backward and reset, joint spare 4 can not with the 3 joint of location chute. As shown in fig. 8-9, after the back connecting member 2 is reset backwards, the front pushing block 9 can press backwards to act on the front end of the reset pressing plate 7, so that the reset pressing plate 7 moves backwards to be reset, and the pressing block 701 at the front end of the reset pressing plate 7 is separated from the side protruding block 4b; then the clamping piece 4 can be ejected upwards again under the action of the spring 6 and is clamped and matched with the positioning chute 3 at the foremost end; afterwards, the back connecting piece 2 can be moved forward relative to the fixing base 1 again for adjustment.

As shown in fig. 2-4, an elastic member 14 is further disposed between the back connector 2 and the fixing base 1, specifically: the elastic member 14 is arranged in the front-rear direction; the left side and the right side of the fixed seat 1 are provided with accommodating grooves 15 arranged along the front-back direction in a mirror image mode, and the elastic pieces 14 are arranged in the accommodating grooves 15; the elastic member 14 is specifically an annular rubber band, the rear end of the elastic member 14 is connected with the fixed seat 1 through a screw, and the front end of the elastic member 14 is connected with the front end of the bottom surface of the back connecting member 1 through a screw. When the back connecting piece 1 slides forwards relative to the fixed seat 1, the elastic piece 14 deforms and can provide a tendency of the back connecting piece 1 to reset backwards; then, as shown in fig. 6, after the back connecting member 1 moves forward to the maximum distance so that the pressing block 701 presses the upper end of the side protruding block 4b, the back connecting member 1 can reset back by itself under the action of the elastic member 14; so that the adjustment operation is very convenient.

As shown in fig. 10, the present invention further provides a chair, which comprises a chair back a, a support B for connecting and supporting the chair seat, and the chair back support adjustment mechanism; wherein the support B comprises a strut 16 positioned longitudinally at the rear end; the fixing seat 1 is arranged at the upper end of the supporting rod 16, and the front end of the back connecting piece 2 is connected with the chair back A. When the chair back A is adjusted, a user can directly grasp the chair back A to move forwards, so that the chair back A can stay at a plurality of positions; if the chair back A needs to be reset, the chair back A only needs to be pulled forwards to a large distance, and then the chair back A can be automatically reset backwards under the action of the elastic piece 14. Thereby leading the chair back A to be capable of adjusting back and forth in a reciprocating way, and the adjustment operation to be very simple and convenient; and the structure is simple.

The present invention and its embodiments have been described above schematically, and the description is not limited thereto, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art should understand that without departing from the spirit of the present invention, the person skilled in the art should not inventively design the similar structural modes and embodiments to the technical solution, and all shall fall within the protection scope of the present invention.

Claims (10)

1. A chair back support adjustment device, comprising:

a fixed seat and a back connecting piece; the back connecting piece is arranged along the front-back direction and is in sliding fit in the fixed seat, and the back connecting piece can slide back and forth relative to the fixed seat;

the sliding positioning mechanism comprises positioning chutes which are arranged on the back connecting piece at intervals along the front-back direction and clamping pieces which are arranged in the fixed seat and can elastically stretch along the longitudinal direction; the back connecting piece is provided with a use state and an adjusting state, and in the use state, the clamping piece is clamped and matched with the positioning chute up and down to limit the back connecting piece to move backwards; in an adjusting state, the back connecting piece moves forwards, a first inclined plane is arranged in the positioning chute, and a second inclined plane is correspondingly arranged at the upper end of the clamping piece; the first inclined plane and the second inclined plane are mutually extruded to enable the clamping piece to elastically contract so as to exit the positioning chute; the clamping piece always has the tendency of being clamped with the positioning chute;

the reset mechanism comprises a reset pressure plate which is arranged in the fixed seat in a sliding way, and a front push block and a rear push block which can push the reset pressure plate to move and are respectively arranged at the front end and the rear end of the back connecting piece; when the back connecting piece moves forwards to the rear push block to push the reset pressure plate to move forwards so as to act on the clamping piece to keep the elastic contraction state all the time, the back connecting piece can reset backwards; when the back connecting piece is reset backwards until the front push block pushes the reset pressure plate to move backwards and to be staggered with the clamping piece, the clamping piece is elastically reset and clamped in the positioning chute again.

2. The seatback support adjustment device of claim 1, wherein: the positioning chute is arranged on the bottom surface of the back connecting piece, and the clamping piece comprises a clamping convex block which is positioned in the middle and protrudes upwards and side convex blocks which are respectively positioned on two sides and sink relative to the clamping convex block; the clamping lug is configured to be in clamping fit with the positioning chute, and the second inclined plane is formed on the clamping lug; the lateral part protruding block is configured to be capable of being in up-and-down extrusion fit with the reset pressing plate so that the clamping piece can be always kept in an elastic contraction state.

3. The seatback support adjustment apparatus of claim 2, wherein: the side section of the positioning chute is in a right-angled trapezoid shape; the first inclined plane is a groove wall on one side of the positioning chute, and the first inclined plane inclines towards the front upper part from back to front; the side cross-sectional shape of joint lug is right trapezoid shape correspondingly, and when back of the body connecting piece slided forward, first inclined plane and second inclined plane extrusion fit shrunk downwards with effect joint spare.

4. The seatback support adjustment apparatus of claim 2, wherein: pressing blocks protruding forwards are respectively arranged on two sides of the front end of the reset pressing plate; the rear push block can abut against the rear end of the reset pressure plate and push the reset pressure plate to move forwards so that the press block is pressed at the upper end of the side convex block.

5. The seatback support adjustment apparatus of claim 4, wherein: the fixed seat is internally provided with an embedded groove in a concave manner, the reset pressing plate is embedded in the embedded groove, and the reset pressing plate can move back and forth in the embedded groove; the elastic piece is arranged in the middle of the front end of the caulking groove; elastic strips capable of elastically deforming along the left and right directions are respectively arranged on the left side and the right side of the reset pressure plate, and clamping heads are arranged at the end parts of the elastic strips; the lateral walls of the left side and the right side of the caulking groove are respectively and correspondingly provided with a groove which is spaced from the front side to the rear side, and the clamping head can be clamped and matched with the groove.

6. The seatback support adjustment device of claim 5, wherein: the front push blocks are arranged on two sides of the front end of the back connecting piece in a mirror image manner; the rear push blocks are arranged on two sides of the rear end of the back connecting piece in a mirror image manner; an avoidance sliding groove for avoiding the front push block and the rear push block is correspondingly and concavely arranged in the fixed seat along the front and rear directions; and the avoiding chute is communicated with the caulking groove in front and back.

7. The seatback support adjustment device of claim 1, wherein: a longitudinal movable sinking groove for accommodating the clamping piece is arranged in the front end of the fixed seat, and the clamping piece is arranged in the movable sinking groove; and a longitudinal spring acting on the clamping piece is arranged between the clamping piece and the movable sinking groove, and the spring is configured to ensure that the clamping piece always has the tendency of clamping with the positioning chute.

8. The seatback support adjustment apparatus of claim 1, wherein: the elastic part is arranged between the fixed seat and the back connecting part; the elastic piece is arranged along the front-back direction, and the front end and the back end of the elastic piece are respectively connected with the back connection and the fixed seat; the elastic member moves forward in response to the back connection member and is elastically deformed accordingly to provide an elastic force for returning the back connection member backward.

9. The seatback support adjustment device of claim 8, wherein: the elastic piece is an elastic band or a rubber band.

10. A seat, characterized by: comprising a chair back, a seat behind the chair back, and a chair back support adjustment mechanism as claimed in any one of claims 1 to 9; the support is provided with a longitudinal support rod positioned at the rear end; the fixing seat is arranged at the upper end of the supporting rod, and the front end of the back connecting piece is connected with the chair back.

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