CN220631623U - Chair and chair back front-back adjusting mechanism thereof - Google Patents

Abstract

The utility model discloses a chair and a chair back front-back adjusting mechanism thereof, which comprises: the first connecting piece is provided with a first groove with a forward opening, and a first through hole is also formed in the first connecting piece; the second connecting piece is provided with a second groove with a backward opening, and a plurality of gear grooves are also formed in the second connecting piece; a guide member; the adjusting piece is provided with a limiting block; the guide piece is fixedly connected with the first groove, the front end of the guide piece extends out of the first groove, and the second connecting piece is sleeved on the guide piece through the second groove and can move back and forth in the first groove along the guide piece; one end of the adjusting piece is positioned in the first groove, the other end of the adjusting piece extends out of the first groove through the first through hole, and the limiting block is matched with the gear groove in a clamping mode. In this scheme, the user only need remove the regulating part and make the stopper leave the gear recess, can adjust the sitting degree of seat back and forth, when the user adjusts to suitable sitting degree, remove the regulating part and make the stopper card can in the gear recess.

Description

Chair and chair back front-back adjusting mechanism thereof

Technical Field

The utility model relates to the field of seats, in particular to a seat and a back front-back adjusting mechanism thereof.

Background

In daily life, both adults and children remain seated for a long time to work or learn, fulfilling various duties. Since many users sit for a long period of time, it is important to properly adjust the seat for each user to provide greater comfort. It is also important that the worker avoid sitting in the exact same location for a long period of time.

To improve the comfort of the seat, some adjustments are typically made to accommodate the user's body shape. These adjustments typically include adjustments in seat depth. The depth of the seat is important, and some seats cannot be adjusted so that the lumbar of the user is not effectively supported, which is often the most important. In many prior art, a seating solution capable of adjusting the depth of a seat is provided, for example, patent application publication No. CN207979388U discloses a novel child seat, in which a seat depth adjusting safety lock is opened to adjust the seat forward or backward through a seat depth adjusting lever, but an adjusting device of the seat is installed below the seat, a user cannot conveniently touch and adjust the seat depth while sitting, and the user cannot intuitively see a gear of the seat depth on the seat, so that the adjustment of the seat depth of the seat is required repeatedly, and a lot of time is wasted.

Disclosure of Invention

In order to solve the technical problems, the utility model aims to provide a seat and a back front-back adjusting mechanism thereof, and a user can adaptively adjust the sitting depth of the seat when sitting.

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

a back-to-back adjustment mechanism comprising:

the first connecting piece is provided with a first groove with a forward opening, and the side wall of the first connecting piece is also provided with a first through hole; the rear end of the first connecting piece is fixedly connected with the chair back or integrally formed;

the second connecting piece is provided with a second groove with a backward opening, the outer side wall of the second connecting piece is also provided with a plurality of gear grooves, and the gear grooves are arranged in rows along the front-back direction; the front end of the second connecting piece is fixedly connected with the chair seat;

a guide member;

the adjusting piece is provided with a limiting block;

the rear end of the guide piece is fixedly connected with the bottom of the first groove, the front end of the guide piece extends out of the first groove, and the second connecting piece is sleeved on the guide piece through the second groove and can move back and forth in the first groove along the guide piece; one end of the adjusting piece provided with a limiting block is positioned in the first groove, the other end of the adjusting piece extends out of the first groove through the first through hole, and the limiting block on the adjusting piece is matched with the gear groove of the second connecting piece in a clamping mode.

Like this, when the user sits the sitting degree of depth that needs to adjust the seat on the seat, only need remove the regulating part and make the stopper leave the gear recess, thereby can back and forth movement first connecting piece adjust the sitting degree of depth of seat, when the user adjusts suitable sitting degree, remove the regulating part and make the stopper card can in the gear recess.

Preferably, the adjusting piece comprises a button and a connecting frame, the button and the limiting block are respectively arranged at two opposite ends of the connecting frame, the connecting frame and the limiting block are positioned at the front part of the first groove, the rear end of the second connecting piece passes through the connecting frame and then is sleeved on the guide piece, and the button extends out of the first groove through the first through hole; the connecting frame is in sliding fit with the first connecting piece, and a reset spring is arranged between the connecting frame and the first connecting piece. In this way, the user can leave the limiting block from the gear groove by pressing the button, the elastic potential energy of the reset spring is increased, and the user continuously presses the button and moves the first connecting piece back and forth to adjust the sitting depth of the seat; when the user adjusts to proper sitting depth, the button is loosened, the connecting frame is reset under the action of the reset spring, and the limiting block is automatically clamped into the corresponding gear groove.

Preferably, the first through hole is arranged on the upper side wall of the first connecting piece, the button is arranged at the upper end of the connecting frame, the limiting block is arranged at the lower end of the connecting frame, and the gear groove is arranged on the lower side wall of the second connecting piece; the button is pressed downwards, the connecting frame slides downwards, the limiting block is separated from the gear groove, and the reset spring is deformed; releasing the button, resetting the connecting frame under the action of the reset spring, and clamping the limiting block in the gear groove; the reset spring, the limiting block and the button are positioned on the same straight line.

Preferably, the first connecting piece comprises a first shell and a second shell, the first shell and the second shell are in clamping fit, and the first shell and the second shell surround to form the first groove; the first shell and the second shell are respectively provided with a chute in a relative mode, and two side edges of the connecting frame are respectively arranged in the chute on the corresponding side and can move along the chute. The first connecting piece is formed by splicing the first shell and the second shell, the installation of the chair back front-back adjusting mechanism is facilitated, sliding fit between the connecting frame and the first connecting piece is realized by arranging the sliding grooves on the first shell and the second shell, and the movement of the first connecting frame is guided.

Preferably, the guide piece is provided with a guide groove, the guide groove is arranged along the front-back direction, a limiting rod is arranged in the guide groove in a penetrating manner, the limiting rod is fixedly connected with the second connecting piece, and when the second connecting piece moves back and forth in the first groove along the guide piece, the limiting rod moves back and forth in the guide groove.

Preferably, the outer side surface of the side wall of the guide piece is also provided with a plurality of pits, the pits are arranged in rows along the front-back direction, and one side of the second connecting piece, which is close to the pits, is provided with a limiting protrusion matched with the pits.

Preferably, the concave pits on the guide piece are in one-to-one correspondence with the gear grooves on the second connecting piece. Therefore, when one gear is moved, the limit protrusions and the pits are matched with friction, a prompt of gear change is generated for a user, and the use feeling of the user is good.

Preferably, the guide piece is arranged obliquely upwards from front to back in sequence, and the second groove is arranged obliquely upwards from front to back in sequence; and one side, close to the seat, of the second connecting piece is also provided with a plurality of gear marks, and the gear marks correspond to the gear grooves one by one. Therefore, when a user sits, the user can intuitively see the gear of the current seat, directly judge whether the sitting depth of the seat needs to be adjusted, and do not need to repeatedly debug the sitting depth of the seat.

The chair comprises a chair back, a chair seat and chair legs, wherein the chair legs are arranged below the chair seat, and the chair back is connected with the chair seat through the chair back front-back adjusting structure.

Preferably, the left side of the bottom of the seat is provided with a front mounting position and a rear mounting position which are fixedly connected with the second connecting piece, and the right side of the bottom of the seat is provided with a front mounting position and a rear mounting position which are fixedly connected with the second connecting piece.

The utility model has the following beneficial effects due to the adoption of the technical scheme: according to the utility model, when a user sits on the seat and needs to adjust the sitting depth of the seat, the user does not need to leave the seat, and only needs to move the adjusting piece to enable the limiting block to leave the gear groove, the first connecting piece and the chair back can be moved back and forth to adjust the sitting depth of the seat, when the user adjusts the sitting depth to be suitable, the adjusting piece is moved to enable the limiting block to be clamped in the gear groove, the relative position of the chair back and the chair seat can be fixed, and the sitting depth of the seat is convenient and quick to adjust.

Drawings

FIG. 1 is a schematic view of a seat in accordance with the present utility model;

FIG. 2 is a schematic view of the back-to-back adjustment structure of the present utility model;

FIG. 3 is a schematic view of the back front-rear adjustment structure of the present utility model with the second housing removed;

FIG. 4 is a cross-sectional view of the back-to-front adjustment structure of the present utility model;

FIG. 5 is an exploded view of the back-to-back adjustment mechanism of the present utility model;

fig. 6 is a schematic view of the structure of fig. 1 at another angle.

Reference numerals:

100. a chair back; 200. a seat; 201. a mounting position; 300. chair legs; 400. an armrest;

1. a first connector; 101. a first housing; 102. a second housing; 11. a first groove; 111. a chute; 12. a first through hole;

2. a second connector; 21. a second groove; 22. a gear groove; 23. a gear mark; 24. a limit rod; 25. a limit protrusion;

3. a guide member; 31. a guide groove; 32. pit;

4. an adjusting member; 41. a limiting block; 42. a button; 43. and (5) connecting a frame.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present utility model and should not be construed as limiting the utility model.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not 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 specified, the meaning of "a plurality" is two or more, unless otherwise clearly defined.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

For convenience of description, in the present utility model, a position where a user sits on a seat is referred to as a front, and vice versa, a side close to the ground is referred to as a lower, and vice versa.

As shown in fig. 1 and 6, a chair back 100, a chair seat 200, chair legs 300 and a pair of armrests 400, wherein the chair back 100 is connected with the chair seat 200 through a back front-rear adjusting structure, the chair legs 300 are installed below the chair seat 200, and the pair of armrests 400 are respectively installed on the back front-rear adjusting structures at the corresponding sides.

A back-front-rear adjustment mechanism as shown in fig. 2 to 5, comprising:

the first connecting piece 1 is provided with a first groove 11 with a forward opening, and the side wall of the first connecting piece 1 is also provided with a first through hole 12; the rear end of the first connecting piece 1 is fixedly connected with the chair back 100 or integrally formed;

the second connecting piece 2 is provided with a second groove 21 with a backward opening, the outer side wall of the second connecting piece 2 is also provided with a plurality of gear grooves 22, and the gear grooves 22 are arranged in rows along the front-back direction; the front end of the second connecting piece 2 is fixedly connected with the chair seat 200;

a guide 3;

the adjusting piece 4 is provided with a limiting block 41;

the rear end of the guide piece 3 is fixedly connected with the bottom of the first groove 11, the front end of the guide piece 3 extends out of the first groove 11, and the second connecting piece 2 is sleeved on the guide piece 3 through the second groove 21 and can move back and forth in the first groove 11 along the guide piece 3; one end of the adjusting piece 4 provided with a limiting block 41 is located in the first groove 11, the other end of the adjusting piece 4 extends out of the first groove 11 through the first through hole 12, and the limiting block 41 on the adjusting piece 4 is in clamping fit with the gear groove 22 of the second connecting piece 2.

Thus, in the present utility model, when the sitting depth of the seat needs to be adjusted, the user does not need to leave the seat, and only needs to move the adjusting member 4 to make the stopper 41 leave the gear groove 22, so that the first connecting member 1 can be unlocked, and at this time, the seat back 100 can be moved back and forth by moving the first connecting member 1 back and forth, so as to adjust the sitting depth of the seat; when the user adjusts the sitting depth, the adjusting member 4 is moved to clamp the limiting block 41 in the gear groove 22, so that the relative position of the chair back 100 and the chair seat 200 can be fixed, and the adjustment of the sitting depth of the chair is completed. In the utility model, the sitting depth of the seat is convenient and quick to adjust.

In one embodiment, the limiting block 41 is located above the guide member 3, the first through hole 12 is disposed on the upper side wall of the first connecting member 1, and the gear groove 22 is disposed on the upper side wall of the second connecting member 2. In this way, the adjusting member 4 is moved up and down to make the stopper 41 be locked or unlocked by being separated from the gear groove 22.

In another embodiment, as shown in fig. 5, the adjusting member 4 includes a button 42 and a connection frame 43, the button 42 and the stopper 41 are respectively disposed at two opposite ends of the connection frame 43, the connection frame 43 and the stopper 41 are located at the front part of the first groove 11, the rear end of the second connecting member 2 passes through the connection frame 43 and is sleeved on the guide member 3, and the button 42 protrudes out of the first groove 11 through the first through hole 12; the connecting frame 43 is in sliding fit with the first connecting piece 1, and a return spring is arranged between the connecting frame 43 and the first connecting piece 1. Thus, pressing the button 42 causes the connecting frame 43 to slide on the first connecting member 1, so that the stopper 41 leaves the gear groove 22 to unlock the first connecting member 1; the button 42 is released, so that the connecting frame 43 is reset under the action of the reset spring, and the limiting block 41 is clamped into the gear groove 22, so that the first connecting piece 1 is locked.

In the utility model, in order to facilitate the installation of the guide member 3 and the adjusting member 4 in the first groove 11 of the first connecting member 1, the first connecting member 1 includes a first housing 101 and a second housing 102, the first housing 101 and the second housing 102 are in snap fit, and the first housing 101 and the second housing 102 surround the first groove 11. In the present utility model, one sliding groove 111 is disposed on each of the first housing 101 and the second housing 102, and two sides of the connection frame 43 are disposed in the corresponding sliding groove 111 and can move along the sliding groove 111, so as to limit the moving direction of the connection frame 43 and prevent the connection frame 43 from shaking during moving.

In the present utility model, the rear end of the first housing 101 is fixedly connected to the chair back 100 or integrally formed, the first through hole 12 is formed on the side wall of the first housing 101, and after the guide member 3 and the adjusting member 4 are installed in the first housing 101, the second housing 102 is engaged with the first housing 101 in a clamping manner, so that the first groove 11 is formed between the first housing 101 and the second housing 102.

In general, in order to facilitate the user to press the button 42, as shown in fig. 3 to 5, the first through hole 12 is provided on the upper sidewall of the first connector 1, the button 42 is provided on the upper end of the connection frame 43, the stopper 41 is provided on the lower end of the connection frame 43, and the gear groove 22 is provided on the lower sidewall of the second connector 2; the button 42 is pressed downwards, the connecting frame 43 slides downwards, the limiting block 41 is separated from the gear groove 22, and the reset spring is deformed; releasing the button 42, resetting the connecting frame 43 under the action of the reset spring, and clamping the limiting block 41 in the gear groove 22; the return spring, the stopper 41 and the button 42 are positioned on the same straight line.

Because there is certain assembly clearance between the guide member 3 and the second connecting member 2, in the process of moving the first connecting member 1 to enable the guide member 2 to move back and forth in the second groove 21, in order to prevent the guide member 2 from shaking in the second groove 21, a guide groove 31 is formed in the guide member 3, the guide groove 31 is arranged along the front-back direction, a limiting rod 24 is arranged in the guide groove 31 in a penetrating manner, the limiting rod 24 is fixedly connected with the second connecting member 2, and when the second connecting member 2 moves back and forth in the first groove 11 along the guide member 3, the limiting rod 24 moves back and forth in the guide groove 31. By providing the stopper rod 24 and the guide groove 31, the guide member 3 is guided to move forward and backward in the second groove 21.

In the present utility model, as shown in fig. 3 to 5, the outer side surface of the side wall of the guide member 3 is further provided with a plurality of pits 32, the plurality of pits 32 are arranged in rows along the front-rear direction of the guide member 3, one side of the second connecting member 2 near the pits 32 is provided with a limit protrusion 25 matched with the pits 32, and the limit protrusion 25 may be integrally formed in the second groove 21 of the second connecting member 2 or may be mounted on the second connecting member 2, and the pits 32 on the guide member 3 are in one-to-one correspondence with the gear grooves 22 on the second connecting member 2. Like this, at the in-process of removing first connecting piece 1 and guide 3, every shift position that removes all can produce "click" sound to there is obvious card between gear and the gear to indicate that the user's gear has changed the gear, user experience is better.

In order to prevent the guide member 3 from getting stuck during the movement in the second recess 21, the front end of the guide member 3 is arranged in a circular arc shape.

In the present utility model, a plurality of gear marks 23 are further disposed on the side of the second connecting member 2 near the seat 200, and the gear marks 23 and the gear grooves 22 are in one-to-one correspondence. When a user sits, the user can intuitively see the gear of the current seat, directly judge whether the sitting depth of the seat needs to be adjusted, and do not need to repeatedly debug the sitting depth of the seat.

Considering that the higher the height of the student is in the growth and development process, the higher the waist height of the student is, so that the chair back height needs to be adjusted besides the sitting depth of the chair, and the chair back can better support the waist of the student. In the present utility model, the guide members 3 are disposed obliquely upward in order from front to back, and the second grooves 21 are disposed obliquely upward in order from front to back. Like this, when adjusting the seat and sit the degree of depth, remove first connecting piece 1 back and forth movement back of the chair 100, guide 3 in the first connecting piece 1 moves along the slope of second recess 21, when adjusting the seat and sit the degree of depth, also adjusts the height of back of the chair 100 to the student is to the seat to sit degree of depth, the demand of back of the chair height of different growth stages of adaptation.

As shown in fig. 1 and 6, in the present embodiment, the left and right sides of the backrest 100 are respectively connected to the seat 200 through the backrest front-rear adjustment structure, and the rear ends of the two first connectors 1 are respectively fixedly connected to or integrally formed with the left and right sides of the backrest 100. In another embodiment, the rear ends of the two first links 1 are connected to form a seat back fixing bracket at the rear side of the seat, on which the seat back 100 is mounted.

As shown in fig. 6, the left side of the bottom of the seat 200 is provided with a front mounting position 201 and a rear mounting position 201 for fixedly connecting with the second connecting member 2, the right side of the bottom of the seat 200 is provided with a front mounting position 201 and a rear mounting position 201 for fixedly connecting with the second connecting member 2, and the front ends of the two second connecting members 2 are respectively fixedly mounted on the mounting positions 201 on the corresponding sides of the seat 200 through bolts, so that the adjustment range of the sitting depth of the seat can be further increased. For example, when the student is slimmer, the front end of the second connecting member 2 may be fixed to the front mounting position 201 by bolts, and when the sitting depth is further required to be increased, the front end of the second connecting member 2 may be fixed to the rear mounting position 201 instead.

Considering that the higher the height of the student is, the arms of the student will be increased accordingly during the growth and development of the student, a pair of armrests 400 are respectively mounted on the first connectors 1 on the corresponding sides, so that the armrests 400 can be correspondingly adjusted while adjusting the chair back 100.

All features described in the description, the appended claims and the drawings, either alone or in any combination, are important features of the present utility model.

In the description of the present specification, the descriptions of the terms "one embodiment," "some embodiments," "one implementation," "a particular implementation," "other implementations," "examples," "particular examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment, implementation, or example of the present utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described above may be combined in any suitable manner in any one or more embodiments, implementations, or examples. The technical scheme disclosed by the utility model also comprises the technical scheme that any one or more specific features, structures, materials or characteristics are formed singly or in combination.

Although embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that variations, modifications, alternatives, variations, deletions of parts, additions of features, or re-combination of features may be made to the above embodiments by those skilled in the art without departing from the spirit and principles of the utility model, all such simple modifications, equivalents, and adaptations of the embodiments as may be made by the principles of the utility model and without departing from the scope of the utility model.

Claims (10)

1. A back-and-back adjustment mechanism, comprising:

the connecting device comprises a first connecting piece (1), wherein a first groove (11) with a forward opening is formed in the first connecting piece (1), and a first through hole (12) is formed in the side wall of the first connecting piece (1); the rear end of the first connecting piece (1) is fixedly connected with the chair back (100) or integrally formed;

the second connecting piece (2), the second connecting piece (2) is provided with a second groove (21) with a backward opening, the outer side wall of the second connecting piece (2) is also provided with a plurality of gear grooves (22), and the gear grooves (22) are arranged in rows along the front-back direction; the front end of the second connecting piece (2) is fixedly connected with the chair seat (200);

a guide (3);

the adjusting piece (4), a limiting block (41) is arranged on the adjusting piece (4);

the rear end of the guide piece (3) is fixedly connected with the bottom of the first groove (11), the front end of the guide piece (3) extends out of the first groove (11), and the second connecting piece (2) is sleeved on the guide piece (3) through the second groove (21) and can move back and forth in the first groove (11) along the guide piece (3); one end of the adjusting piece (4) provided with a limiting block (41) is located in the first groove (11), the other end of the adjusting piece (4) extends out of the first groove (11) through the first through hole (12), and the limiting block (41) on the adjusting piece (4) is matched with the gear groove (22) of the second connecting piece (2) in a clamping mode.

2. The chair back front and back adjusting mechanism according to claim 1, wherein the adjusting piece (4) comprises a button (42) and a connecting frame (43), the button (42) and the limiting block (41) are respectively arranged at two opposite ends of the connecting frame (43), the connecting frame (43) and the limiting block (41) are positioned at the front part of the first groove (11), the rear end of the second connecting piece (2) passes through the connecting frame (43) and is sleeved on the guide piece (3), and the button (42) extends out of the first groove (11) through the first through hole (12); the connecting frame (43) is in sliding fit with the first connecting piece (1), and a return spring is arranged between the connecting frame (43) and the first connecting piece (1).

3. The chair back front and back adjusting mechanism according to claim 2, wherein the first through hole (12) is arranged on the upper side wall of the first connecting piece (1), the button (42) is arranged at the upper end of the connecting frame (43), the limiting block (41) is arranged at the lower end of the connecting frame (43), and the gear groove (22) is arranged on the lower side wall of the second connecting piece (2); the button (42) is pressed downwards, the connecting frame (43) slides downwards, the limiting block (41) is separated from the gear groove (22), and the reset spring is deformed; releasing the button (42), resetting the connecting frame (43) under the action of the reset spring, and clamping the limiting block (41) in the gear groove (22); the reset spring, the limiting block (41) and the button (42) are positioned on the same straight line.

4. A chair back front and rear adjustment mechanism according to claim 2, characterized in that the first connecting piece (1) comprises a first housing (101) and a second housing (102), the first housing (101) and the second housing (102) are in clamping fit, and the first housing (101) and the second housing (102) surround to form the first groove (11); the first shell (101) and the second shell (102) are respectively and oppositely provided with a chute (111), and two side edges of the connecting frame (43) are respectively arranged in the chute (111) at the corresponding side and can move along the chute (111).

5. The chair back front and back adjusting mechanism according to claim 1, wherein the guide piece (3) is provided with a guide groove (31), the guide groove (31) is arranged along the front and back direction, a limiting rod (24) is arranged in the guide groove (31) in a penetrating manner, the limiting rod (24) is fixedly connected with the second connecting piece (2), and when the second connecting piece (2) moves back and forth in the first groove (11) along the guide piece (3), the limiting rod (24) moves back and forth in the guide groove (31).

6. The back front-rear adjusting mechanism according to claim 1, wherein a plurality of pits (32) are further formed on the outer side surface of the side wall of the guide member (3), the plurality of pits (32) are arranged in a row along the front-rear direction, and a limit protrusion (25) matched with the pits (32) is arranged on one side, close to the pits (32), of the second connecting member (2).

7. A chair back front and rear adjustment mechanism according to claim 6, characterized in that the recesses (32) on the guide member (3) are in one-to-one correspondence with the gear grooves (22) on the second connecting member (2).

8. A chair back front and rear adjusting mechanism according to claim 1, wherein the guide member (3) is provided obliquely upward in order from front to rear, and the second groove (21) is provided obliquely upward in order from front to rear; and a plurality of gear marks (23) are further arranged on one side, close to the seat (200), of the second connecting piece (2), and the gear marks (23) and the gear grooves (22) are in one-to-one correspondence.

9. A seat comprising a back (100), a seat (200) and legs (300), said legs (300) being mounted under the seat (200), wherein said back (100) is connected to the seat (200) by a back-front-rear adjustment mechanism according to any one of claims 1-8.

10. A seat according to claim 9, wherein the left side of the bottom of the seat (200) is provided with front and rear mounting locations (201) for fixedly connecting with the second connecting member (2), and the right side of the bottom of the seat (200) is provided with front and rear mounting locations (201) for fixedly connecting with the second connecting member (2).