CN213216124U - Seat and seat chassis thereof - Google Patents

Abstract

The utility model discloses a chair and a chair chassis thereof, wherein the chair chassis comprises a first connecting seat, a chassis seat, a second connecting seat and a third connecting seat, the chassis seat is provided with a spring plate, a sliding block and a position adjusting mechanism, wherein the front end of the elastic sheet is connected with the front part of the chassis seat, the rear end of the elastic sheet is movably connected with the second connecting seat, the sliding block is positioned below the elastic sheet to support the elastic sheet, the position adjusting mechanism is used for controlling the sliding block to slide back and forth on the chassis seat, the automatic control device comprises a control handle, a gear and a rack, wherein the control handle is arranged outside a chassis base, one end of the control handle extends into the chassis base, the gear is arranged at one end of the control handle, which is positioned in the chassis base, and rotates along with the rotation of the control handle, the gear is in transmission connection with the rack, the control handle is rotated to drive the gear to rotate, and then the rack and a sliding block are driven to move back and forth on the chassis base. The elastic force adjusting structure is simple in mounting structure, low in mounting precision requirement, low in cost and not prone to damage gears.

Description

Seat and seat chassis thereof

Technical Field

The utility model relates to a seat technical field, concretely relates to seat and seat chassis thereof.

Background

The chair is an indispensable furniture for people to work or rest, and plays a role in bearing the weight of people. Along with the improvement of living standard of people, the requirement on the comfort of the seat is higher and higher, and the back of the chair of the existing seat can rotate to different angles in a front-back mode relative to the base so as to improve the comfort of use. In order to realize the functions, the chair back and the base are mainly connected in two modes, one mode is that the chair back and the base are connected by an elastically deformable plastic piece, and the rotation and the elastic support of the chair back are realized through the elastic deformation of the plastic piece; the other is that the chair back and the base are connected by a rotating shaft, and an elastic connecting piece (such as a spring) is arranged between the chair back and the base, so that the chair back and the base can elastically rotate. The existing connection mode between the chair back and the base has the defects that the reliability of the connection by adopting plastic parts is poor, and the chair back and the base are easy to fatigue and break; the structure adopting the connection of the rotating shaft and the elastic connecting piece is complex and has high cost.

Therefore, chinese patent document with publication number CN206354749U discloses a connecting mechanism for a seat chassis and a seat back, which includes a rotating connecting structure for the chassis and the seat back, and is characterized in that the connecting mechanism further includes a spring plate and a blocking block, the spring plate is disposed on the chassis, the front end of the spring plate is fixed on the front portion of the chassis, the rear end of the spring plate extends to the rear portion of the chassis, and the rotating connecting structure is disposed on the rear side of the rear end of the spring plate; the blocking block is arranged above the elastic sheet and is tightly pressed on the elastic sheet; the chair back is provided with an upper pressing sheet which extends forwards at the position of the rotary connecting structure, and the upper pressing sheet acts on the lower side of the rear end of the elastic sheet. The connecting mechanism has the advantages of good reliability, long service life, simple structure and low manufacturing cost. Chinese patent document with the publication number of CN209733156U discloses an elasticity adjusting mechanism for a chair seat chassis, which comprises a chassis seat, wherein a plurality of elastic sheets are arranged on the chassis seat along the front-back direction of the chassis, an adjusting mechanism is arranged below the elastic sheets, the adjusting mechanism comprises a sliding block capable of moving along the front-back direction of the chassis and a control handle for controlling the movement of the sliding block, a propping strip abutted against the lower end of the elastic sheet is arranged at the upper end of the sliding block, when the elasticity is required to be adjusted, the control handle only needs to rotate the control handle to drive the sliding block to move, the propping strip of the sliding block moves along the lower end of the elastic sheet and props against the elastic sheet, so that the deformation range of the elastic sheet can be adjusted to adjust the elasticity of the elastic sheet, the elasticity adjusting mechanism replaces the traditional compression spring through the elastic sheet, the installation is simpler, the elastic sheet only needs to be placed, the elastic piece has higher practicability, the elastic change of the elastic piece is more balanced, and the elastic adjusting effect is better.

However, in the process of use, the person skilled in the art finds that the adjusting mechanisms for controlling the movement of the stopper/sliding block in the above documents convert the rotation of the handle into the movement of the stopper/sliding block by adopting the cooperation of the bevel gear piece, and the adjusting mechanisms are not only complicated in structure but also have high requirements on the installation accuracy; when the handle on the adjusting mechanism drives the stop block/sliding block to move, if the handle is rotated continuously when a large rotation block is encountered, the teeth on the handle gear or the driving bevel gear or the driven bevel gear are damaged.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model aims at providing a simple structure, to the lower elasticity adjustment structure of a seat base of adjustment structure installation accuracy requirement.

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

a seat chassis comprises a first connecting seat, a chassis seat, a second connecting seat and a third connecting seat which form a four-bar linkage mechanism, wherein the first connecting seat is hinged with the front part of the chassis seat, the second connecting seat is hinged with the rear part of the chassis seat, and the third connecting seat is positioned above the chassis seat and is simultaneously hinged with the first connecting seat and the second connecting seat; the chassis seat is fixedly connected with the chair legs of the chair, the second connecting seat is fixedly connected with the chair back, and the third connecting seat is fixedly connected with the bottom of the chair seat; the chassis base is also provided with a plurality of spring plates, a plurality of sliding blocks and a position adjusting mechanism for adjusting the positions of the sliding blocks on the chassis base, wherein the front end of the elastic sheet is fixedly connected with the front part of the chassis seat, the rear end of the elastic sheet is movably connected on the second connecting seat, the sliding block is positioned below the elastic sheet and supports the elastic sheet, the position adjusting mechanism is used for controlling the sliding block to slide back and forth on the chassis seat, the position adjusting mechanism comprises a control handle, a gear and a rack which are arranged on the chassis seat, the control handle is arranged on the outer side of the chassis seat, one end on the control handle extends into the chassis base, the gear is arranged at one end of the control handle, which is positioned in the chassis base, and rotates along with the rotation of the control handle, the gear and the rack are in transmission connection, the rack is fixedly connected with the sliding block or integrally formed, the control handle is rotated to drive the gear to rotate, and then the rack and the sliding block are driven to move back and forth on the chassis base. Therefore, the rack drives the sliding block to move at the lower end of the elastic sheet, so that the deformation range of the elastic sheet is adjusted, and the elasticity of the elastic sheet is adjusted; compared with the prior art, the position adjusting mechanism is simple and has low requirement on the installation precision.

Preferably, the chassis base is provided with two sliding blocks and two elastic pieces respectively arranged above the two sliding blocks, and the two sliding blocks are arranged on the left side and the right side of the rack.

Preferably, the chassis base is further fixedly provided with a plurality of supporting blocks, the supporting blocks are located below the elastic pieces and support the elastic pieces, the supporting blocks are arranged behind the sliding blocks, and limiting baffles are arranged on the left side and the right side of the supporting blocks and/or the sliding blocks. The position of the elastic sheet on the supporting block and/or the sliding block can be limited by the limiting baffle, and the elastic sheet is prevented from shaking left and right.

Preferably, the sliding block is slidably disposed on the base through a sliding rail and/or a sliding groove.

Preferably, the control handle is connected with a transmission shaft, the part of the control handle extending into the chassis base is a transmission shaft, the transmission shaft is a polygonal shaft, the transmission shaft penetrates through one supporting block and then is sequentially sleeved with a first spring, a transmission part and a gear, the transmission part is sleeved on the transmission shaft through a polygonal hole matched with the transmission shaft and synchronously rotates with the transmission shaft, the gear is radially fixed and circumferentially unfixed with the transmission shaft, one end of the first spring abuts against the supporting block, the other end of the first spring abuts against the transmission part, and the transmission part and the gear are in transmission fit through a v-shaped surface. The control handle is rotated, the transmission shaft drives the transmission piece to synchronously rotate, and the transmission piece is in transmission fit with the gear through the v-shaped surface so as to drive the gear to rotate; when the gear meets large resistance, the axial component force of the reaction force given to the transmission part by the gear through the v-shaped surface is greater than the elastic force of the first spring, so that the transmission part is separated from the gear, and the damage of the gear and the transmission part is avoided.

Preferably, the end surface of the transmission member, which is close to the gear, extends towards the gear to form a first v-shaped surface, and the gear is provided with a second v-shaped surface meshed with the first v-shaped surface. Therefore, when the control handle is rotated to transmit, the transmission part is tightly meshed with the gear, the transmission is accurate, and the transmission efficiency is high.

Preferably, the chassis base and the second connecting base are provided with locking mechanisms, and each locking mechanism comprises a plurality of locking grooves which are arranged on the second connecting base along the vertical direction, a lock tongue which is arranged on the chassis base, a spring device which is arranged on the chassis base and a control rope which is connected with the lock tongue; the chassis base is provided with a guide groove for accommodating the spring bolt, the spring device is arranged in the guide groove, one end of the spring device acts on the side wall of the guide groove, and the other end of the spring device acts on the front part of the spring bolt to enable the spring bolt to be inserted into the locking groove backwards.

Preferably, a spring positioning block is arranged in the guide groove, the spring positioning block is integrally formed or fixedly connected with the lock tongue, the control rope is fixed on the spring positioning block, the control rope is pulled to drive the spring positioning block to slide so as to drive the lock tongue to move in a single direction, the spring device comprises a second spring and two third springs distributed on the left side and the right side of the second spring, the rear ends of the second spring and the third springs are abutted against the side wall of the spring positioning block, the front ends of the second spring and the third springs are abutted against the side wall of the guide groove, and the directions of the elastic forces exerted on the spring positioning block by the second spring and the third springs are opposite.

Preferably, the second connecting seat is provided with an integrally formed or fixedly connected pressure lever, and the rear end of the elastic sheet abuts against the lower part of the pressure lever.

A chair comprises a chair back, a chair seat, chair legs and a chair chassis as described above.

The utility model discloses owing to adopted above technical scheme to have following beneficial effect:

1. in the utility model, the position adjusting mechanism has simple structure, low requirement on installation precision, convenient installation and lower cost;

2. the control handle on the position adjusting mechanism drives the sliding block to move, and even when the sliding block is already at the starting point or the end point or meets a large obstruction, the gear cannot rotate, and the transmission part or the gear cannot be damaged by continuously rotating the control handle.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention;

fig. 2 is a schematic structural view of the connector assembly of fig. 1 with a third connecting seat removed;

fig. 3 is a partial schematic structural diagram of an embodiment of the present invention;

FIG. 4 is a schematic view of the structure of FIG. 3 with the base removed;

FIG. 5 is a schematic view of the structure of FIG. 4 at another angle;

FIG. 6 is a schematic structural view of the gear and the transmission shaft according to the embodiment of the present invention;

FIG. 7 is a schematic view of the structure of the transmission spring, the transmission member and the transmission shaft according to the embodiment of the present invention;

fig. 8 is a schematic view of a gear end face of an embodiment of the present invention;

reference numerals: 1. a first connecting seat; 2. a chassis base; 3. a second connecting seat; 301. a pressure lever; 302. a locking groove; 4. a third connecting seat; 5. a spring plate; 6. a slider; 7. a position adjustment mechanism; 701. a control handle; 7011. a drive shaft; 702. a gear; 7021. a second v-shaped face; 703. a rack; 704. a spring; 705. a transmission member; 7051. a first v-shaped face; 8. a support block; 9. a latch bolt; 10. and a spring positioning block.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

As shown in fig. 1, the embodiment discloses a chair, including the back of the chair (not shown in the figure), seat support (not shown in the figure), chair foot (not shown in the figure) and seat chassis, seat chassis includes first connecting seat 1, chassis seat 2, second connecting seat 3 and third connecting seat 4, chassis seat 2 and the chair foot fixed connection of seat, second connecting seat 3 and back of the chair fixed connection, third connecting seat 4 and seat support bottom fixed connection. In this embodiment, the chassis base 2 is fixedly connected with the legs of the seat through the support rods.

As shown in fig. 1 to 5, the first connecting seat 1, the chassis base 2, the second connecting seat 3, and the third connecting seat 4 constitute a four-bar linkage, the first connecting seat 1 is hinged to the front portion of the chassis base 2, the second connecting seat 3 is hinged to the rear portion of the chassis base 2, and the third connecting seat 4 is located above the chassis base 2 and is hinged to the first connecting seat 1 and the second connecting seat 3 at the same time. Preferably, the four-bar linkage is provided with a limiting device. In this embodiment, it has an arc hole to open on the lateral wall of chassis seat 2, and second connecting seat 3 moves in the arc hole of chassis seat 2 through spacing post, can restrict this four-bar linkage's deformation range like this, and it is spacing to carry out four-bar linkage.

The chassis base 2 is also provided with a plurality of elastic sheets 5, a plurality of sliding blocks 6 and a position adjusting mechanism 7 for adjusting the positions of the sliding blocks 6 on the chassis base 2, wherein the elastic sheets 5 are made of elastic materials, preferably glass fiber strips; wherein the front end of the elastic sheet 5 is fixedly connected with the front part of the chassis seat 2, the rear end of the elastic sheet 5 is movably connected on the second connecting seat, thereby leading the elastic sheet 5 to have certain elastic deformation all the time, the sliding block 6 is positioned below the elastic sheet 5 and supports the elastic sheet 5, the position adjusting mechanism 7 is used for controlling the sliding block 6 to slide back and forth on the chassis base 2, the position adjusting mechanism 7 comprises a control handle 701, a gear 702 and a rack 703 which are arranged on the chassis base 2, the control handle 701 is arranged on the outer side of the chassis base 2, one end of the control handle 701 extends into the chassis base 2, the gear 702 is mounted at one end of the control handle 701, which is located in the chassis base 2, and rotates along with the rotation of the control handle 701, the gear 702 is in transmission connection with the rack 703, the rack 703 is fixedly connected with the sliding block 6 or is integrally formed, the control handle 701 is rotated to drive the gear 702 to rotate, and then the rack 703 and the sliding block 6 are driven to move back and forth on the chassis base 2. When elasticity needs to be adjusted, through rotating control handle 701, control handle 701 drives gear 702 and rotates to make rack 703 back-and-forth movement on base 2 to drive sliding block 6 and remove and push up tight shell fragment 5 along the lower extreme of shell fragment 5, thereby make the deformation scope of shell fragment 5 can adjust its elasticity, thereby make the back of the chair have different rigidity when the back-up, satisfy different users' demand, this position control mechanism simple structure, convenient operation is laborsaving, has very high practicality.

In this embodiment, the second connecting seat 3 is provided with an integrally formed or fixedly connected pressing rod 301, and the rear end of the elastic piece 5 abuts against the lower side of the pressing rod 301.

Preferably, the chassis base 2 is provided with two sliding blocks 6 and two elastic pieces 5 respectively disposed above the two sliding blocks 6, and the two sliding blocks 6 are disposed on the left and right sides of the rack 703. Therefore, the two sliding blocks 6 are uniformly stressed and always kept in a parallel state when sliding back and forth, so that the elastic force of the elastic sheet 5 is uniformly changed, and the elastic force adjusting effect is good.

Preferably, the sliding block 6 is slidably disposed on the base 2 through a sliding rail and/or a sliding groove, the sliding groove corresponding to the sliding rail in shape is disposed at the bottom of the sliding block 6, the sliding block 6 slides back and forth on the sliding rail through the sliding groove, the sliding rail is provided with a plurality of sliding rails, and the sliding rails are parallel to each other at intervals, so that the sliding of the sliding block 6 is more stable.

As shown in fig. 2 to 5, a plurality of supporting blocks 8 are further fixedly disposed on the base 2, the number of the supporting blocks 8 may be two or three or four, and the like, as required, the supporting blocks 8 are located below the elastic pieces 5 to support the elastic pieces 5, the supporting blocks 8 are disposed behind the sliding blocks 6, and the left and right sides of the supporting blocks 8 and/or the sliding blocks 6 are provided with limit baffles. Adopt supporting shoe 8, use supporting shoe 8 to produce elastic deformation for shell fragment 5 as the fulcrum, realize elastic support to the back of the chair, when sliding block 6 slides around going on, displacement about can preventing shell fragment 5 from producing for shell fragment 5 atress is more even, and stability and travelling comfort are better in the use.

In order to lock the position of the chair back, the chassis base 2 and the second connecting base 3 are provided with locking mechanisms, and each locking mechanism comprises a plurality of locking grooves which are arranged on the second connecting base 3 along the vertical direction, a lock tongue 9 arranged on the chassis base 2, a spring device arranged on the chassis base 2 and a control rope connected with the lock tongue 9; be equipped with the guide way that is used for holding spring bolt 9 in chassis seat 2, spring assembly sets up in this guide way, and spring assembly's one end is used in on the lateral wall of guide way, and the other end is used in the front portion of spring bolt 9 and makes spring bolt 9 insert the locking groove backward in, be equipped with spring locating piece 10 in the guide way, spring locating piece 10 and spring bolt 9 integrated into one piece or fixed connection, the control rope is fixed on spring locating piece 10, thereby the pulling control rope drives spring locating piece 10 and slides and drive spring bolt 9 unidirectional movement. When the chair is in work, the control rope is pulled to drive the spring positioning block 10 to slide so as to drive the lock tongue 9 to overcome the elastic force of the spring device and move backwards to withdraw from the locking groove, the position of the chair back can be freely adjusted, when the proper position is adjusted, the control rope is loosened, and the lock tongue 9 is reinserted into the locking groove to be locked under the elastic force action of the spring device.

Preferably, the spring positioning block 10 may be disposed in the guide groove through a sliding groove and/or a sliding rail, or the spring positioning block 10 may be directly movably disposed in the guide groove.

Preferably, the spring device includes a second spring and two third springs distributed on the left and right sides of the second spring, wherein the rear ends of the second spring and the third springs abut against the side wall of the spring positioning block 10, the front ends of the second spring and the third springs abut against the side wall of the guide groove, and the directions of the elastic forces applied by the second spring and the third springs to the spring positioning block 10 are opposite. Therefore, the bidirectional elastic force enables the lock tongue 9 to slide more smoothly in the locking groove, and when the control rope pulls the lock tongue 9 out of the locking groove, the direction of the elastic force generated by the second spring is the same as the direction of the pulling force of the control rope, so that more labor is saved; when first spring promoted spring bolt 9 and inserted the locking groove, the second spring had played the cushioning effect, and the impact of the production when making the back of the chair locking is littleer, lets the user more comfortable.

In this embodiment, the portion of the control handle 701 extending into the chassis base 2 is a transmission shaft 7011, the transmission shaft 7011 passes through a support block 8 to be connected to the gear 702, the support block 8 is further provided with a groove, the gear 702 is provided with a circle of protrusions, the protrusions on the gear 702 are just clamped in the groove of the support block 8, and the axial position of the gear 702 on the transmission shaft 7011 is further limited.

As shown in fig. 5 and 6, the transmission shaft 41 is a polygonal shaft, the transmission shaft 7011 is sequentially sleeved with a first spring 704, a transmission member 705 and a gear 702 after passing through a support block 8, the transmission member 705 is sleeved on the transmission shaft 7011 through a polygonal hole adapted to the transmission shaft 7011 and synchronously rotates with the transmission shaft 7011, the gear 702 is radially fixed and circumferentially unfixed with the transmission shaft 7011, one end of the first spring 704 abuts against the support block 8, the other end of the first spring abuts against the transmission member 705, the transmission member 705 is in transmission fit with the gear 702 through a v-shaped surface, a first v-shaped surface 7051 extends from an end surface of the transmission member 705 close to the gear 702, and a second v-shaped surface 7021 engaged with the first v-shaped surface 7051 is arranged on. Thus, in the process of rotating the control handle 701, the control handle 701 drives the transmission shaft 7011 and the transmission member 705 to synchronously rotate, and further drives the gear 702 to rotate through the meshing transmission between the transmission member 705 and the gear 702, so that the rack 703 and the sliding block 6 are driven to move on the chassis base 2; when the gear 702 is blocked from rotating, the axial component of the reaction force of the gear, which is given to the transmission part 7011 by the v-shaped surface, is greater than the elastic force of the first spring, so that the transmission part 7011 is separated from the gear 702, and the gear 702 and the transmission part 7011 are prevented from being damaged.

Although embodiments of the present invention have been shown and described, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the principles and spirit of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A seat chassis comprises a first connecting seat (1), a chassis seat (2), a second connecting seat (3) and a third connecting seat (4) which form a four-bar linkage, wherein the first connecting seat (1) is hinged with the front part of the chassis seat (2), the second connecting seat (3) is hinged with the rear part of the chassis seat (2), and the third connecting seat (4) is positioned above the chassis seat (2) and is hinged with the first connecting seat (1) and the second connecting seat (3) simultaneously; the chassis seat (2) is fixedly connected with the chair legs of the chair, the second connecting seat (3) is fixedly connected with the chair back, and the third connecting seat (4) is fixedly connected with the bottom of the chair seat; the chassis base (2) is provided with a plurality of elastic sheets (5), a plurality of sliding blocks (6) and a position adjusting mechanism (7) for adjusting the position of the sliding blocks (6) on the chassis base (2), wherein the front ends of the elastic sheets (5) are fixedly connected with the front part of the chassis base (2), the rear ends of the elastic sheets (5) are movably connected on the second connecting seat (3), the sliding blocks (6) are positioned below the elastic sheets (5) and support the elastic sheets (5), the position adjusting mechanism (7) is used for controlling the sliding blocks (6) to slide back and forth on the chassis base (2), the chassis base is characterized in that the position adjusting mechanism (7) comprises a control handle (701), a gear (702) and a rack (703) which are arranged on the chassis base (2), the control handle (701) is arranged on the outer side of the chassis base (2), and one end of the control handle (701) extends into the chassis base (2), the gear (702) is installed at one end of the control handle (701) which is located in the chassis seat (2) and rotates along with the rotation of the control handle (701), the gear (702) is in transmission connection with the rack (703), the rack (703) is fixedly connected with the sliding block (6) or is integrally formed, the control handle (701) is rotated to drive the gear (702) to rotate, and then the rack (703) and the sliding block (6) are driven to move back and forth on the chassis seat (2).

2. The seat chassis as claimed in claim 1, wherein the chassis base (2) is provided with two sliding blocks (6) and two elastic sheets (5) respectively arranged above the two sliding blocks (6), and the two sliding blocks (6) are arranged at the left and right sides of the rack (703).

3. A seat chassis according to claim 1, wherein the sliding block (6) is slidably arranged on the chassis base (2) by means of a sliding track and/or a sliding groove.

4. The seat chassis according to claim 1, wherein a plurality of supporting blocks (8) are further fixedly arranged on the chassis base (2), the supporting blocks (8) are positioned below the elastic pieces (5) to support the elastic pieces (5), the supporting blocks (8) are arranged behind the sliding blocks (6), and limit baffles are arranged on the left side and the right side of the supporting blocks (8) and/or the sliding blocks (6).

5. The seat chassis according to claim 4, wherein the part of the control handle (701) extending into the chassis base (2) is a transmission shaft (7011), the transmission shaft (7011) is a polygonal shaft, the transmission shaft (7011) penetrates through a supporting block (8) and then is sequentially sleeved with a first spring (704), a transmission member (705) and a gear (702), the transmission member (705) is sleeved on the transmission shaft (7011) through a polygonal hole matched with the transmission shaft (7011) and rotates synchronously with the transmission shaft, the gear (702) and the transmission shaft (7011) are radially fixed and circumferentially unfixed, one end of the first spring (704) abuts against the supporting block (8), the other end of the first spring abuts against the transmission member (705), and the transmission member (705) and the gear (702) are in transmission fit through a v-shaped surface.

6. The seat pan of claim 5, wherein the end of the transmission member (705) adjacent to the gear (702) extends towards the gear (702) and is provided with a first v-shaped surface (7051), and the gear (702) is provided with a second v-shaped surface (7021) which is engaged with the first v-shaped surface (7051).

7. A seat chassis according to claim 1, characterized in that the chassis base (2) and the second connecting base (3) are provided with locking means comprising a number of locking slots arranged in the second connecting base (3) in an up-down direction, a latch tongue (9) arranged on the chassis base (2), a spring means arranged on the chassis base (2) and a control cord connected to the latch tongue (9); be equipped with the guide way that is used for holding spring bolt (9) in chassis seat (2), spring assembly sets up in this guide way, and spring assembly's one end is used in the lateral wall of guide way, and the other end is used in the front portion of spring bolt (9) and makes spring bolt (9) insert locking groove backward.

8. The seat chassis according to claim 7, wherein a spring positioning block (10) is arranged in the guide groove, the spring positioning block (10) is integrally formed or fixedly connected with the latch bolt (9), the control rope is fixed on the spring positioning block (10), the spring positioning block (10) is driven to slide by pulling the control rope so as to drive the latch bolt (9) to move in a single direction, the spring device comprises a second spring and two third springs distributed on the left side and the right side of the second spring, wherein the rear ends of the second spring and the third spring abut against the side wall of the spring positioning block (10), the front ends of the second spring and the third spring abut against the side wall of the guide groove, and the elastic force exerted by the second spring and the third spring on the spring positioning block (10) is in opposite directions.

9. The seat chassis according to claim 1, wherein the second connecting seat (3) is provided with an integrally formed or fixedly connected pressure lever (301), and the rear end of the elastic sheet (5) abuts against the lower part of the pressure lever (301).

10. A chair comprising a back, a seat, legs and a chair chassis according to any one of claims 1 to 9.

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