CN219331137U

CN219331137U - Back-chasing mechanism

Info

Publication number: CN219331137U
Application number: CN202223105783.9U
Authority: CN
Inventors: 戴龙飞; 陈龙; 路跃辉
Original assignee: Anji Shuyi Smart Home Co ltd
Current assignee: Anji Shuyi Smart Home Co ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-07-14
Anticipated expiration: 2032-11-21

Abstract

The utility model relates to a back-tracking mechanism, which comprises a support base, an elastic piece and a four-bar mechanism consisting of an upper connecting bar, a lower connecting bar, a front connecting seat and a rear connecting seat, wherein a support arm is arranged between the four-bar mechanism and the support base, and the head end of the support arm is hinged with the four-bar mechanism; the tail end of the supporting arm is rotationally connected with the supporting base, and the rear connecting seat is in sliding connection with the supporting base; the elastic member acts on a four bar linkage or support arm. The cooperation of four link mechanism and elastic component can make leading connecting seat be in the state of stretching all the time, when receiving the leaning force of equidimension, the elastic component can produce corresponding elasticity and resist this leaning force in order to keep leading connecting seat state of stretching forward to can make leading connecting seat can show the state of jacking all the time.

Description

Back-chasing mechanism

Technical Field

The utility model belongs to the technical field of seats, and particularly relates to a back-following mechanism and a back-following chair.

Background

The chair is the most commonly used tool in our daily life, and the waist on its back of the chair or back of the chair can make us sit more comfortable, in order to adapt to different crowds 'demand, current back of the chair or waist lean on all to set up to adjustable to be convenient for adjust to suitable state according to different crowds' demand.

The patent number 202210008609.8 discloses a self-attaching back-following waist rest, when a user adjusts sitting posture forwards, the user drives a pneumatic support rod 16 or a hydraulic telescopic rod or an electric telescopic rod to act through a switch and drives a support rod piece 25 to rotate around a hinge point at the upper end of the support rod piece, and as the two support rod pieces 25 are arranged, the front movement of the waist rest 15 with unchanged elevation angle can be ensured under the effect of reverse torsion, so that the waist rest 15 can be attached to the waist and the back of the user all the time.

Although the waist rest can be adjusted to the position of being attached to the waist and the back of the user through the pneumatic supporting rod, when in actual use, the sitting posture of a human body is changed frequently, and the waist rest can be attached to the waist and the back of the user continuously after the sitting posture is changed each time, so that the waist rest is very troublesome to use and cannot be attached to the waist and the back automatically according to the back movement.

Disclosure of Invention

In order to solve the technical problems, the utility model aims to provide the back-following mechanism, which can always keep the four-bar mechanism in a forward extending state under the action of elastic force of an elastic piece, and automatically adjusts the forward extending distance according to the stressed size.

Still further provide a back chair that follows, can be according to the position of sitting of user difference, automatically regulated back of the chair or waist lean forward extent for back of the chair or waist lean on can closely laminate human waist back, convenient and practical.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

the back-tracking mechanism comprises a support base, an elastic piece and a four-bar mechanism consisting of an upper connecting bar, a lower connecting bar, a front connecting seat and a rear connecting seat, wherein the front connecting seat and the rear connecting seat are used for connecting a chair back or a waist rest; the tail end of the supporting arm is rotationally connected with the supporting base, and the rear connecting seat is in sliding connection with the supporting base; the back-following mechanism has an extending state and a retracting state, and the elastic piece acts on the four-bar mechanism or the supporting arm; in the stretching state, the rear connecting seat is close to the tail end of the supporting arm, and the front connecting seat is positioned at a front position; when the back-tracking mechanism is in a retracted state, the rear connecting seat is far away from the tail end of the supporting arm, the front connecting seat is in a rear position, and the elastic piece deforms to generate reset elastic force, so that the back-tracking mechanism always has a trend of being converted from the retracted state to the extended state.

The four-bar mechanism can rotate relatively at the movable joint, and the four-bar mechanism can enable the front connecting seat positioned at the front side to keep horizontal and vertical stretching or retracting action all the time when the front connecting seat rotates relatively to move, so that the chair back or the waist rest cannot deflect in an angle, and can be clung to the waist and the back of a human body.

The support arm can be used for supporting the four-bar linkage on the one hand, and on the other hand also can drive the four-bar linkage to move together through the rotation of the support arm, and can drive each other to move between the two, and the elasticity that the elastic component produced in the back-following mechanism can act on four-bar linkage or support arm, drives one of them to move, then can drive another also to take place corresponding removal.

The back-following mechanism has various states due to the relative rotation or movement of the four-bar mechanism and the supporting arm, and in the extending state, the rear connecting seat is close to the tail end of the supporting arm, and is in the initial state at the moment, the front connecting seat connected with the chair back or the waist rest is in the foremost position; when the leaning external force is applied, the back-rest type back-rest device is in a retracted state, and the elastic piece can generate elastic force to enable the rear connecting seat and the tail end of the supporting arm which are ready to be far away from each other to have a trend of approaching each other, namely, the front connecting seat has a trend of extending forwards, so that the back-rest effect is realized.

Preferably, wherein the support arm head end is hinged with the four-bar linkage means: the head end of the supporting arm is hinged with the upper connecting rod or the lower connecting rod.

Preferably, the elastic member is any one of a tension spring, a compression spring or a gas spring, one end of the elastic member is connected to the rear connecting seat, the other end of the elastic member is connected to the supporting base, and the elastic member deforms when the rear connecting seat moves.

When the elastic piece is respectively connected with the rear connecting seat and the supporting base and is subjected to leaning external force, the elastic piece can displace under the driving of the rear connecting seat so as to generate elastic force, under the leaning force, the rear connecting seat can move upwards, and the elastic force acts on the rear connecting seat downwards, so that the rear connecting seat has a downward movement trend; when the leaning force is removed, the rear connecting seat can move downwards under the action of the elastic force, so that the front connecting seat extends forwards to fit the waist and the back of the human body.

Preferably, the gas spring is a self-locking gas spring.

Preferably, the two ends of the upper connecting rod are respectively hinged with the front connecting seat and the rear connecting seat, and the two ends of the lower connecting rod are respectively hinged with the front connecting seat and the rear connecting seat to form a four-bar mechanism.

The upper connecting rod and the lower connecting rod are matched and hinged on the front connecting seat and the rear connecting seat, and the front end of the supporting arm is hinged on the upper connecting rod or the lower connecting rod, so that when one of the upper connecting rod and the lower connecting rod relatively moves, the other of the upper connecting rod and the lower connecting rod relatively moves, and the other of the upper connecting rod and the lower connecting rod correspondingly moves. For example, when the rear connecting seat moves downwards, the supporting arm rotates along with the rear connecting seat to the front side, and the upper connecting rod and the lower connecting rod extend forwards together, so that the front connecting seat has a trend of moving forwards.

Preferably, the elastic member is a torsion spring, and the torsion spring may be disposed at any movable joint in the four-bar mechanism, or the torsion spring may be disposed at a hinge position of the support arm and the support base.

In addition, the elastic piece can also be a torsion spring, and is arranged at any movable joint in the four-bar mechanism, or the torsion spring can be arranged at the hinge position of the supporting arm and the supporting base, and also in the initial state, the front connecting seat is arranged at the forefront side, so that when one part correspondingly rotates under the leaning external force, the torsion spring can generate the elastic force for resetting, so that the torsion spring has the resetting trend, and further, after the leaning external force is removed, the elastic force can drive the front connecting seat to reset to the initial state, and the back-following effect is realized.

Preferably, the rear connection base is slidably connected to the support base: the support base is provided with a through chute along the vertical direction, the back surface of the support base is provided with a limiting plate, and the side wall of the limiting plate extends out to form a sliding block penetrating through the chute; the limiting plate is connected with the rear connecting seat through a sliding block.

The sliding groove and the limiting plate are arranged to enable the rear connecting seat to be more stable when sliding occurs, and the rear connecting seat cannot deviate.

The back-following mechanism in another scheme comprises a supporting arm, a four-bar mechanism consisting of a supporting base, an upper connecting rod, a lower connecting rod and a front connecting seat for connecting a chair back or a waist rest, wherein the head end of the supporting arm is hinged with the four-bar mechanism, and the tail end of the supporting arm is rotationally and slidingly connected with the supporting base; the tail end of the supporting arm is rotationally connected with the supporting base, and the rear connecting seat is in sliding connection with the supporting base; the back-following mechanism has an extending state and a retracting state, and the elastic piece acts on the four-bar mechanism or the supporting arm; in the stretching state, the tail end of the supporting arm slides along the supporting base in one direction, and the front connecting seat is positioned at a front position; when the back-tracking mechanism is in a retracted state, the tail end of the support arm slides along the support base towards the other direction, the front connecting seat is positioned at a back position, and the elastic piece deforms to generate reset elastic force, so that the back-tracking mechanism always has a trend of being converted into an extended state from the retracted state.

Similarly, in this scheme, when receiving same lean on external force, what take place to slide relatively with the support base between is the support arm, the relative movement of support arm also can make the elastic component produce corresponding displacement equally, and then produces elasticity and make it have the trend that resets, when removing this lean on external force, the elasticity will drive and make its action that takes place to reset, realizes the effect of chasing the back.

Preferably, the articulation of the head end of the support arm with the four bar linkage means: the head end of the supporting arm is hinged with the upper connecting rod or the lower connecting rod.

Preferably, the elastic element is any one of a tension spring, a compression spring or a gas spring, one end of the elastic element is connected to the tail end of the support arm, the other end of the elastic element is connected to the support base, and the elastic element deforms when the tail end of the support arm moves.

The difference from the first solution is that the deformation of the elastic element is caused by the movement of the tail end of the support arm.

Preferably, the gas spring is a self-locking gas spring.

And for both sliding connection and articulation between the support arm tail and the support base means: the tail end of the support arm is hinged to the side wall of a sliding seat, a sliding groove is formed in the middle of the support base, a sliding block penetrating through the sliding groove is connected to the other side wall of the sliding seat, and a limiting plate is arranged on the back of the support base and connected with the sliding block, so that the tail end of the support arm can relatively rotate while moving in the sliding groove.

The back-following chair comprises the back-following mechanism and a chair seat, wherein the chair seat is connected with a chair back frame, the lower end of the supporting base is connected to the chair back frame, and the front end of the front connecting seat is connected with a chair back or a waist rest; in the extended state, the back or lumbar rest is in a forward extended position.

When the back-following mechanism is specifically applied to the back-following chair, the back and the waist-following chair can be adaptively moved to the position of the waist-back of the human body according to different crowds or different sitting postures, so that the back-following mechanism is convenient to use, and the experience of a user is greatly improved.

Compared with the prior art, the utility model has the beneficial effects that:

1. the front connecting seat can be always in a forward extending state by the cooperation of the four-bar mechanism and the elastic piece, when leaning forces with different magnitudes are received, the elastic piece can generate corresponding elastic force to resist the leaning forces so as to keep the forward extending state of the front connecting seat, and therefore the front connecting seat can always be in a jacking state;

2. compared with the method that the pneumatic support rod directly drives the support rod to rotate so as to adjust the lumbar support to extend forwards, the elastic piece is connected with one end of the four-bar mechanism in sliding connection or one end of the support arm in sliding connection, so that the stroke of the elastic piece is greatly shortened;

3. the existing pneumatic support rod is always in a supporting state for the support rod piece and the waist rest, the performance of the pneumatic support rod is fast reduced after long-term use, and the pneumatic support rod is connected with the four-bar mechanism through the support arm, so that the load of a part of elastic pieces is shared, and the service life of the pneumatic support rod can be prolonged.

Drawings

FIG. 1 is a schematic view of the whole structure of the back-following mechanism in the extended state;

FIG. 2 is a schematic diagram of the whole structure of the back-following mechanism in the extended state;

FIG. 3 is a cross-sectional view of a back-following mechanism in accordance with the present utility model;

FIG. 4 is a schematic view of the whole structure of the back-following mechanism in the retracted state;

FIG. 5 is a schematic diagram showing the whole structure of the back-following mechanism in the retracted state;

FIG. 6 is a schematic diagram of an exploded structure of the back-following mechanism of the present utility model;

FIG. 7 is a schematic diagram of an exploded structure of the back-following mechanism of the present utility model;

fig. 8 is a second cross-sectional view of the back-following mechanism of the present utility model.

Description of the drawings: 1. a support base; 2. an upper connecting rod; 3. a lower connecting rod; 4. a front connecting seat; 5. a rear connecting seat; 6. a support arm; 7. an elastic member; 8. a chute; 9. a limiting plate; 10. a sliding block.

Detailed Description

The following describes the embodiments of the present utility model in detail with reference to the drawings.

In order to improve the comfort in sitting and be applicable to the leaning demand of various crowds, traditional armchairs can all set up back or waist to adjustable, can adjust back or waist to suitable position in order to laminate to human back according to different crowds' use habit but because human position of sitting is the time variation, if want to keep laminating effect of back, just need to adjust back and waist always, very trouble.

The back-following chair in this embodiment, as shown in fig. 1-8, comprises a back-following mechanism and a chair seat, wherein the back-following mechanism comprises a supporting base 1 and a front connecting seat 4, the chair seat is connected with a chair back frame, the lower end of the supporting base 1 is connected to the chair back frame, and the front end of the front connecting seat 4 is connected with a chair back or a waist rest; in the extended state, the back or lumbar rest is in a forward extended position.

When the back-following mechanism is specifically applied to the back-following chair, the chair back and the waist-following chair can be adaptively moved to the position of the waist-back of the human body according to different people or different sitting postures, so that the back-following mechanism is convenient to use, and the experience of a user is greatly improved. The back-following mechanism has various embodiments:

in embodiment one; the back-following mechanism comprises a support base 1, an elastic piece 7, and a four-bar mechanism consisting of an upper connecting bar 2, a lower connecting bar 3, a front connecting seat 4 and a rear connecting seat 5, wherein the front connecting seat 4 and the rear connecting seat 5 are used for connecting a chair back or a waist rest, a supporting arm 6 is further arranged between the four-bar mechanism and the support base 1, and the head end of the supporting arm 6 is hinged with the four-bar mechanism; the tail end of the supporting arm 6 is rotationally connected with the supporting base 1, and the rear connecting seat 5 is in sliding connection with the supporting base 1; the back-following mechanism has an extended state and a retracted state, the elastic element 7 acts on the four-bar mechanism or the supporting arm 6; in the stretching state, the rear connecting seat 5 is close to the tail end of the supporting arm 6, and the front connecting seat 4 is positioned at a front position; when in a retraction state, the rear connecting seat 5 is far away from the tail end of the supporting arm 6, the front connecting seat 4 is positioned at a rear position, and the elastic piece 7 deforms to generate reset elastic force, so that the back-following mechanism always has a trend of changing from the retraction state to the extension state.

In order to achieve the effect and the function of back-following, the four-bar mechanism can rotate relatively at the movable joints of the four-bar mechanism, and the four-bar mechanism can enable the front connecting seat 4 positioned at the front side to keep horizontal and vertical stretching or retracting actions all the time when the front connecting seat 4 rotates relatively to move, so that the back of the chair or the lumbar support can not deflect at an angle, and can be clung to the lumbar of a human body.

Then the four-bar linkage is hinged with the support arm 6, and the hinged mode is adopted because the four-bar linkage mechanism and the support arm 6 need to rotate and move correspondingly in the back-tracking action, the four-bar linkage mechanism is formed by sliding connection of the rear support seat 5 and the support base 1 when being connected to the support base 1, meanwhile, the support arm 6 is hinged with the support base 1, and the elastic piece 7 is arranged between the support arm 6 and the rear support seat, and acts on the four-bar linkage mechanism or the support arm 6, so that the back-tracking effect can be realized by mutual cooperation of the four-bar linkage mechanism and the support arm 6.

The method comprises the following specific steps: the back-following mechanism is in an initial stretching state, the rear connecting seat 5 is close to the tail end of the supporting arm 6, when leaning is carried out, the rear connecting seat 5 is far away from the supporting arm 6, and the deformation generated by the elastic piece 7 can generate elastic force, so that the rear connecting seat 5 and the supporting arm 6 have a trend of approaching each other, but the force is smaller than leaning force, so that leaning is not influenced; when leaning on the back, the human body leans forward to separate from the back or the waist, the elastic force can drive the rear connecting seat 5 and the supporting arm 6 to approach each other, so that the front connecting seat 4 stretches forward under the action of the four-bar mechanism, and the back-following effect is realized.

The four-bar linkage mechanism comprises the following specific connection structures: the two ends of the upper connecting rod 2 are respectively hinged with a front connecting seat 4 and a rear connecting seat 5, and the two ends of the lower connecting rod 3 are respectively hinged with the front connecting seat 4 and the rear connecting seat 5 to form a four-bar mechanism.

The upper connecting rod 2 and the lower connecting rod 3 are matched and hinged on the front connecting seat 4 and the rear connecting seat 5, and the front end of the supporting arm 6 is also hinged on the upper connecting rod 2 or the lower connecting rod 3, so that when one of the upper connecting rod 2 and the lower connecting rod 3 moves relatively, the other of the upper connecting rod and the lower connecting rod can correspondingly link. For example, when the rear connecting seat 5 moves downwards, the supporting arm 6 rotates along with the rear connecting seat, and the upper connecting rod 2 and the lower connecting rod 3 also extend along with the rear connecting seat, so that the front connecting seat 4 has a trend of moving forwards, and the front connecting seat 4 hinged with the upper connecting rod 2 and the lower connecting rod 3 always keeps a horizontal and vertical moving state when moving due to synchronous movement of the upper connecting rod 2 and the lower connecting rod 3, so that the front connecting seat is more suitable for actual use situations.

The supporting arm 6 can be used for supporting a four-bar mechanism on one hand, and can also drive the four-bar mechanism to move together through the rotation of the supporting arm 6 on the other hand, the elastic force generated by the elastic piece 7 can act on the four-bar mechanism or the supporting arm 7 to drive one of the four-bar mechanism or the supporting arm 7 to move, and the other one can be driven to correspondingly move.

Wherein the head end of the supporting arm 6 is hinged with the four-bar mechanism, which means that: the head end of the supporting arm 6 is hinged with the upper connecting rod 2 or the lower connecting rod 3. The supporting arm 6 and the four-bar linkage can be linked without mutual interference.

In the selection of the elastic piece 7, the elastic piece 7 is any one of a tension spring, a compression spring or a gas spring, one end of the elastic piece 7 is connected to the rear connecting seat 5, the other end of the elastic piece 7 is connected to the supporting base 1, and the elastic piece 7 deforms when the rear connecting seat 5 moves. The gas spring is a self-locking gas spring. The self-locking gas spring can stop at any position in the process by means of some release mechanisms, and after stopping, the locking force can reach more than 10000N.

Then the elastic piece 7 is respectively connected with the rear connecting seat 5 and the supporting base 1, when the elastic piece 7 is subjected to leaning external force, the elastic piece 7 can displace under the drive of the rear connecting seat 5 to generate elastic force, under the leaning force, the rear connecting seat 5 can move upwards, and the elastic force acts downwards on the rear connecting seat 5, so that the rear connecting seat 5 has a downward movement trend; when the leaning force is removed, the rear connecting seat 5 can move downwards under the action of the elastic force, so that the front connecting seat 4 extends forwards to be attached to the waist and the back of the human body.

In addition, the elastic member 7 may be a torsion spring, which may be disposed at any movable joint in the four-bar mechanism, or may be disposed at a hinge position of the support arm 6 and the support base 1.

Also under initial extension state, leading connecting seat 4 is located the front side to when receiving leaning external force, when corresponding rotation takes place for one of them part, the torsional spring just can produce the elasticity that resets equally, makes it have the trend that resets, and then when this leaning external force withdraws the back, the elasticity can drive leading connecting seat 4 and reset to initial state, and then realizes the effect of chasing the back.

In the concrete process of connecting the rear connecting seat 5 and the support base 1, a through chute 8 is formed in the support base 1 along the vertical direction, a limit plate 9 is arranged on the back surface of the support base 1, and a sliding block 10 extends out of the side wall of the limit plate 9 and penetrates through the chute 8; the limiting plate 9 is connected with the rear connecting seat 5 through a sliding block 10.

The sliding chute 8 and the limiting plate 9 are arranged to enable the rear connecting seat 5 to be more stable when sliding, and the rear connecting seat cannot deviate.

In the second embodiment, the back-following mechanism comprises a supporting arm 6 and a four-bar mechanism consisting of a supporting base 1, an upper connecting rod 2, a lower connecting rod 3 and a front connecting seat 4 for connecting a chair back or a waist rest, wherein the head end of the supporting arm 6 is hinged with the four-bar mechanism, and the tail end of the supporting arm 6 is rotatably and slidably connected with the supporting base 1 and an elastic piece 7; the tail end of the supporting arm 6 is rotationally connected with the supporting base 1, and the rear connecting seat 5 is in sliding connection with the supporting base 1; the back-following mechanism has an extending state and a retracting state, and the elastic piece 7 acts on the four-bar mechanism or the supporting arm 6; in the extended state, the tail end of the supporting arm 6 slides along the supporting base 1 towards one direction, and the front connecting seat 4 is positioned at a front position; when in the retraction state, the tail end of the supporting arm 6 slides along the supporting base 1 towards the other direction, the front connecting seat 4 is positioned at a back position, and the elastic piece 7 deforms to generate reset elastic force, so that the back-following mechanism always has a trend of changing from the retraction state to the extension state.

Similarly, in this embodiment, when the same leaning external force is applied, the support arm 6 slides relatively with the support base 1, and the relative movement of the support arm 6 also causes the elastic member 7 to generate corresponding displacement, so that elastic force is generated to enable the elastic member to have a reset trend, and when the leaning external force is removed, the elastic force drives the elastic member to reset, so as to achieve the effect of back-following.

The same as in embodiment one is: the head end of the supporting arm 6 is hinged with the upper connecting rod 2 or the lower connecting rod 3. The four-bar linkage mechanism is the same in composition, two ends of the upper connecting rod 2 are respectively hinged with the front connecting seat 4 and the rear connecting seat 5, and two ends of the lower connecting rod 2 are respectively hinged with the front connecting seat 4 and the rear connecting seat 5 to form the four-bar linkage mechanism.

The selection of the elastic member 7 is also the same as that of embodiment 1, the elastic member 7 is any one of a tension spring, a compression spring or a gas spring, one end of the elastic member 7 is connected to the tail end of the support arm 6, the other end of the elastic member 7 is connected to the support base 1, and the elastic member 7 deforms when the tail end of the support arm 6 moves. The gas spring is a self-locking gas spring.

The elastic member 7 may also be a torsion spring, which may be disposed at any movable joint in the four-bar mechanism, or may be disposed at a hinge position of the support arm 6 and the support base 1.

The same parts as those in the embodiment described above also have the same effects as those in the embodiment.

A difference from the embodiment is that the deformation of the elastic member 7 is caused by the movement of the tail end of the support arm 6.

And for both sliding connection and articulation between the tail end of the support arm 6 and the support base 1 is meant: the tail end of the supporting arm 6 is hinged to the side wall of a sliding seat, a sliding groove 8 is formed in the middle of the supporting base 1, a sliding block 10 penetrating through the sliding groove 8 is connected to the other side wall of the sliding seat, and a limiting plate 9 is arranged on the back of the supporting base 1 and connected with the sliding block 10, so that the tail end of the supporting arm 6 can rotate relatively when the sliding groove 8 moves.

In the initial extended state, the front connecting seat 4 is also positioned at the forefront position, and in the retracted state, the front connecting seat 4 also has a forward extending trend under the action of the elastic piece 7, when the leaning external force is reduced or disappears, the front connecting seat 4 can drive the chair back or the lumbar support to seek the position of the lumbar of the human body forward, thereby realizing the back-following effect, supporting the lumbar and improving the experience of the user.

The foregoing description of the utility model is merely exemplary of the utility model. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions, without departing from the scope of the utility model as defined in the accompanying claims.

Claims

1. The back-tracking mechanism is characterized by comprising a support base (1), an elastic piece (7) and a four-bar mechanism formed by an upper connecting bar (2), a lower connecting bar (3), a front connecting seat (4) and a rear connecting seat (5) which are used for connecting a chair back or a waist rest, wherein a support arm (6) is further arranged between the four-bar mechanism and the support base (1), and the head end of the support arm (6) is hinged with the four-bar mechanism; the tail end of the supporting arm (6) is rotationally connected with the supporting base (1), and the rear connecting seat (5) is in sliding connection with the supporting base (1); the back-following mechanism has an extending state and a retracting state, and the elastic piece (7) acts on the four-bar mechanism or the supporting arm (6); in the stretching state, the rear connecting seat (5) is close to the tail end of the supporting arm (6), and the front connecting seat (4) is positioned at a front position; when in a retraction state, the rear connecting seat (5) is far away from the tail end of the supporting arm (6), the front connecting seat (4) is positioned at a rear position, and the elastic piece (7) deforms to generate reset elastic force, so that the back-following mechanism always has a trend of changing from the retraction state to the extension state.

2. The back-following mechanism according to claim 1, wherein the elastic member (7) is any one of a tension spring, a compression spring or a gas spring, one end of the elastic member (7) is connected to the rear connecting seat (5), the other end of the elastic member (7) is connected to the supporting base (1), and the elastic member (7) deforms when the rear connecting seat (5) moves.

3. The back-following mechanism of claim 2, wherein the gas spring is a self-locking gas spring.

4. The back-following mechanism according to claim 1, wherein the two ends of the upper connecting rod (2) are respectively hinged to the front connecting seat (4) and the rear connecting seat (5), and the two ends of the lower connecting rod (3) are also respectively hinged to the front connecting seat (4) and the rear connecting seat (5) to form a four-bar mechanism.

5. Back-following mechanism according to claim 1, characterized in that the sliding connection of the rear connection seat (5) on the support base (1) means: the support base (1) is provided with a through chute (8) along the vertical direction, the back of the support base (1) is provided with a limiting plate (9), and a sliding block (10) extends out of the side wall of the limiting plate (9) and penetrates through the chute (8); the limiting plate (9) is connected with the rear connecting seat (5) through a sliding block (10).

6. The back-tracking mechanism is characterized by comprising a supporting arm (6) and a four-bar mechanism consisting of a supporting base (1), an upper connecting bar (2), a lower connecting bar (3) and a front connecting seat (4) for connecting a chair back or a waist rest, wherein the head end of the supporting arm (6) is hinged with the four-bar mechanism, the tail end of the supporting arm (6) rotates and is connected with the supporting base (1) in a sliding manner, and an elastic piece (7); the tail end of the supporting arm (6) is rotationally connected with the supporting base (1), and the rear connecting seat (5) is in sliding connection with the supporting base (1); the back-following mechanism is provided with an extending state and a retracting state, and the elastic piece (7) acts on the four-bar mechanism or the supporting arm (6); in an extended state, the tail end of the supporting arm (6) slides along the supporting base (1) towards one direction, and the front connecting seat (4) is positioned at a front position; when the back-tracking mechanism is in a retracted state, the tail end of the supporting arm (6) slides along the supporting base (1) towards the other direction, the front connecting seat (4) is positioned at a back position, and the elastic piece (7) deforms to generate reset elastic force, so that the back-tracking mechanism always has a trend of being converted from the retracted state to the extended state.

7. Back-following mechanism according to claim 1 or 6, characterized in that the articulation of the head end of the support arm (6) with the four-bar mechanism means: the head end of the supporting arm (6) is hinged with the upper connecting rod (2) or the lower connecting rod (3).

8. The back-following mechanism according to claim 6, wherein the elastic member (7) is any one of a tension spring, a compression spring and a gas spring, one end of the elastic member (7) is connected to the tail end of the support arm (6), the other end of the elastic member (7) is connected to the support base (1), and the elastic member (7) deforms when the tail end of the support arm (6) moves.

9. The back-following mechanism of claim 8, wherein the gas spring is a self-locking gas spring.

10. Back-following mechanism according to claim 6, characterized in that the elastic element (7) is a torsion spring, which can be placed at any movable joint in a four-bar mechanism or at the hinge position of the support arm (6) and the support base (1).