SEAT UNIT AND SEAT

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation Application of PCT Application No. PCT/CN 2024/105226 filed on Jul. 12, 2024, which claims priority of Chinese Patent Application No. 202310894279.1 filed on Jul. 20, 2023, and Chinese Patent Application No. 202321915745.1 filed on Jul. 20, 2023, before CNIPA. All the above are hereby incorporated by reference in their entirety as part of the present disclosure.

TECHNICAL FIELD

The present disclosure relates to the technical field of seats, and in particular, to a seat unit and a seat.

BACKGROUND

Existing seat units such as functional sofas and functional seats are mostly configured to perform position adjustment to meet users'multi-scene relaxation needs. Generally, the seat unit includes three major structural portions: a leg portion and a backrest portion adjustably mounted on a seat portion. By adjusting these three major structural portions, the seat unit is configured to present a sitting position, a TV position, and a lying position, wherein the sitting position is manifested as a closed state, the lying position is manifested as an extended state, and the TV position is between the closed state and the extended state. Conventionally, it is required that the leg portion be adjusted first, and then the backrest portion be adjusted, when the seat unit is adjusted from the closed state to the extended state; it is required that the backrest portion be adjusted first, and then the leg portion be adjusted, when the seat unit is adjusted from the extended state to the closed state. That is, the three major structural portions of the seat unit need to satisfy the above order requirement during position adjustment, and disorder will affect the user experience. Moreover, the backrest portion presents a backward tilting state when the seat unit is switched between the TV position and the lying position. During adjustment of this step by a conventional seat bracket, the backrest will have a large distance of backward movement. Therefore, a large adjustment space needs to be reserved between the wall and the backrest portion of the seat unit when the seat unit is placed with the backrest facing a wall, leading to inconvenience in use.

SUMMARY

Provided in a first aspect of the present disclosure is a seat unit, including: a pair of mirror-symmetrically arranged mechanical extension devices that are linked, the mechanical extension device including a seat assembly for attaching a seat portion, a leg assembly adjustably assembled to a front end of the seat assembly, and a backrest assembly adjustably assembled to a rear end of the seat assembly, the seat assembly including a seat frame and a seat bracket that are slidable relative to each other in front-rear directions of the seat assembly, the seat bracket is fixed relative to ground, the leg assembly is pivotally connected to the seat frame, the backrest assembly is configured to be pivotally connected to both the seat frame and the seat bracket, and a pivot connection point between the backrest assembly and the seat frame is configured to move following the seat frame in response to the seat frame sliding relative to the seat bracket; a driving unit configured to drive the mechanical extension device so that the seat unit is switched sequentially among a sitting position, a TV position, and a lying position, with the seat frame sliding relative to the seat bracket; and a first damping member disposed between the seat frame and the seat bracket, or between the backrest assembly and the seat bracket, wherein the first damping member is configured to obstruct the seat frame from sliding relative to the seat bracket toward a front of the seat assembly in response to the seat unit being switched from the sitting position to the lying position; the first damping member is configured to drive the seat frame to slide relative to the seat bracket toward a rear of the seat assembly in response to the seat unit being switched from the lying position to the sitting position.

The first damping member leads to a high resistance for the seat frame to slide relative to the seat bracket toward a front of the seat assembly under action of the driving unit, and a low resistance for the seat frame to slide relative to the seat bracket toward a rear of the seat assembly, so as to cooperate with adjustment of the leg assembly to ensure an adjustment sequence of a leg portion and a backrest portion of the seat unit.

According to an implementation, the seat unit further includes a second damping member, and the second damping member is disposed between the leg assembly and the seat assembly. The second damping member is configured to drive the leg assembly to extend toward a front of the seat assembly in response to the seat unit being switched from the sitting position to the lying position; the second damping member is configured to obstruct the leg assembly from retracting toward a rear of the seat assembly in response to the seat unit being switched from the lying position to the TV position. In some implementations, the second damping member is disposed between the leg assembly and the seat frame.

The second damping member leads to the leg assembly being easier to extend forward in response to the seat unit being switched from the sitting position to the lying position, and the leg assembly being subjected to a certain resistance in response to the seat unit being switched from the lying position to the TV position, cooperating with the first damping member to maintain a stable position adjustment sequence for each part of the seat unit.

According to an implementation, the first damping member is a tension spring or a rubber tube.

According to another implementation, a seat unit includes: a pair of mirror-symmetrically arranged mechanical extension devices that are linked, the mechanical extension device including a seat assembly for attaching a seat portion, a leg assembly adjustably assembled to a front end of the seat assembly, and a backrest assembly adjustably assembled to a rear end of the seat assembly, the seat assembly including a seat frame and a seat bracket that are slidable relative to each other in front-rear directions of the seat assembly, the seat bracket is fixed relative to ground, the leg assembly is pivotally connected to the seat frame, the backrest assembly is configured to be pivotally connected to both the seat frame and the seat bracket, and a pivot connection point between the backrest assembly and the seat frame is configured to move following the seat frame in response to the seat frame sliding relative to the seat bracket; a driving unit configured to drive the mechanical extension device so that the seat unit is switched sequentially among a sitting position, a TV position, and a lying position, with the seat frame sliding relative to the seat bracket; and a second damping member, wherein the second damping member is disposed between the leg assembly and the seat assembly; the second damping member is configured to obstruct the leg assembly from retracting toward a rear of the seat assembly in response to the seat unit being switched from the lying position to the TV position; the second damping member is configured to obstruct the leg assembly from retracting toward a rear of the seat assembly in response to the seat unit being switched from the lying position to the TV position.

With such configuration, the leg assembly of the seat unit is easier to extend forward in response to the seat unit being switched from the sitting position to the lying position, and a retracting action of the leg assembly is subjected to a certain resistance in response to the seat unit being switched from the lying position to the TV position, thereby ensuring a stable sequence of leg position actions during a position switching process of the seat unit.

According to an implementation, the seat unit further includes a fixed beam and a drive beam, where the drive beam is configured to link the leg assemblies of the pair of mechanical extension devices, and the fixed beam is disposed between the seat brackets of the pair of mechanical extension devices; the driving unit is a telescoping member, a movable end of the telescoping member is pivotally connected to the drive beam, and a fixed end of the telescoping member is pivotally connected to the fixed beam.

According to an implementation, the backrest assembly includes an active rod and a driven rod that are pivotally connected, wherein the active rod is pivotally connected to the seat frame; the driven rod is pivotally connected to the seat bracket; and a backrest plate is attached to the active rod.

According to an implementation, the backrest assembly includes an active rod, a first driven rod, a second driven rod, and a backrest mounting rod, where a lower end of the first driven rod and a lower end of the second driven rod are pivotally connected to the seat bracket respectively, an upper end of the first driven rod and an upper end of the second driven rod are pivotally connected to the backrest mounting rod respectively; a lower end of the active rod is pivotally connected to the seat frame, an upper end of the active rod is pivotally connected to any one of the first driven rod, the second driven rod, or the backrest mounting rod; a backrest plate is attached to the backrest mounting rod; a pivot connection point between the lower end of the active rod and the seat frame is configured to move following the seat frame in response to the seat frame sliding relative to the seat bracket.

With such configuration, the backrest plate mounted on the backrest mounting rod is configured to have a lower end thereof follow the seat frame to move forward and rearward while an upper end thereof basically does not move in front-rear directions in response to the seat frame sliding relative to the seat bracket, that is, when the seat unit is switched between the TV position and the lying position, leading to adjustment of a backrest inclination angle of the seat unit and reducing a back-scrubbing sensation during use of the backrest in this process.

According to an implementation, the backrest mounting rod includes a following portion and an attachment portion that are bent and connected, the first driven rod and the second driven rod are pivotally connected to the following portion respectively, and the backrest plate is attached to the attachment portion.

According to an implementation, a first damping surface is disposed on a side of the first driven rod close to the second driven rod, a second damping surface is disposed on a side of the second driven rod close to the first driven rod, and the first damping surface and the second damping surface are in frictional abutment.

Such configuration is capable of improving structural stability of a planar four-bar linkage structure, specifically, improving positional stability of the backrest mounting rod during an adjustment process and repeatability of the position during multiple adjustments.

According to an implementation, the seat unit further includes a third limiting member, where the third limiting member at least partially extends between the first driven rod and the second driven rod; the first driven rod abuts against the third limiting member in response to the seat unit being in the sitting position and the TV position; the second driven rod abuts against the third limiting member in response to the seat unit being in the lying position. The third limiting member herein is for assisting in limiting the backrest assembly.

According to an implementation, a first sliding rail member is disposed on the seat bracket, and a second sliding rail member adapted to the first sliding rail member is disposed on the seat frame; the first sliding rail member and the second sliding rail member are slidably connected.

According to an implementation, the first sliding rail member includes a first base plate, a first outer side plate is disposed on each of two sides of the first base plate, a free end of the first outer side plate is bent inward to form a first inner side plate, and the first base plate is disposed on the seat bracket; the second sliding rail member includes a second base plate, a second inner side plate is disposed on each of two sides of the second base plate, a free end of the second inner side plate is bent outward to form a second outer side plate, and the second base plate is disposed on the seat frame; the second base plate and the second inner side plates disposed on the second base plate are both located between the two first inner side plates, and the second outer side plates are located between the corresponding first outer side plate and first inner side plate; a rolling member is disposed on the second outer side plate, and the rolling member is in rolling abutment or sliding abutment with the first base plate and/or the first outer side plate.

According to an implementation, the rolling member includes a support member disposed on the second outer side plate, and a lower end of the support member is provided with a rolling body that is in rolling abutment or sliding abutment with the first base plate and/or the first outer side plate.

According to an implementation, the seat frame includes a supporting plate, side plates are bent and disposed on two sides of the supporting plate, the second sliding rail member is disposed on the supporting plate and located between the two side plates; at least a part of the first sliding rail member extends between the two side plates.

According to an implementation, the second damping member is any one of a tension spring, a torsion spring, or a rubber tube.

According to an implementation, a first support and a second support are disposed on the seat bracket, the first support is disposed on a side close to the leg assembly, and the second support is disposed on a side close to the backrest assembly.

According to an implementation, the seat unit further includes a first frame beam and a second frame beam, where a first end of the first frame beam and a first end of the second frame beam are both connected to the seat frame of one of the mechanical extension devices; a second end of the first frame beam and a second end of the second frame beam are both connected to the seat frame of the other mechanical extension device; the first frame beam is disposed on a side close to the leg assembly, and the second frame beam is disposed on a side close to the backrest assembly.

According to an implementation, a plurality of hooks are correspondingly and integrally stamped on the first frame beam and the second frame beam, respectively; the seat unit further includes a sinuous spring, an end of the sinuous spring is hooked on the plurality of hooks of the first frame beam, and an opposite end of the sinuous spring is hooked on the corresponding hooks of the second frame beam.

According to an implementation, the leg assembly includes a drive link, a following link, a first extension link, a second extension link, and a footrest member, wherein a first end of the drive link and the following link are both pivotally connected to the seat frame, a second end of the drive link is pivotally connected to a first end of the first extension link, and the following link is pivotally connected to a first end of the second extension link; a second end of the first extension link and a second end of the second extension link are pivotally connected to the footrest member, respectively; the drive link is pivotally connected to the second extension link, and a pivot connection point therebetween is located between two ends of the second extension link; two ends of the drive beam are connected to the corresponding drive links, respectively.

According to an implementation, the leg assembly further includes a first limiting member, the first limiting member is disposed on the second extension link, defining a pivot point between the second extension link and the drive link as a first pivot point, wherein the first limiting member is located between the first end of the second extension link and the first pivot point.

According to an implementation, a pivot point between the following link and the seat frame is defined as a second pivot point, the second pivot point is located between two endpoints of the following link, wherein one end of the following link is pivotally connected to the second extension link, the other end of the following link is pivotally connected to a front end of a transition link, and a front end of the second damping member is connected to a rear end of the transition link. Such configuration is capable of ensuring that the second damping member extends substantially in front-rear directions throughout a position adjustment process of the seat unit, facilitating assembly and avoiding bending of the second damping member due to rotation of the following link after direct assembly with the following link, which would affect the lifespan of the second damping member.

According to an implementation, a pivot point between the drive link and the seat frame is defined as a third pivot point, and the second pivot point is disposed on a side close to the backrest assembly.

According to an implementation, a motor bracket is disposed on the drive beam, and the movable end of the telescoping member is pivotally connected to the motor bracket; a pivot point between the movable end of the telescoping member and the motor bracket is defined as a fourth pivot point, wherein the fourth pivot point is behind the drive beam in response to the seat unit being in the TV position and the lying position; the fourth pivot point is below the drive beam in response to the seat unit being in the sitting position. Such configuration is capable of moving a connection point between the telescoping member and the leg assembly forward, leading to more favorable support for the leg assembly and reducing a risk of the leg assembly falling when the seat unit is in the TV position and the lying position.

According to an implementation, a second limiting member is disposed on the seat frame; the leg assembly is configured to retract toward a rear of the seat assembly and abut against the second limiting member to maintain the sitting position in response to the seat unit being switched from the TV position to the sitting position; the leg assembly is configured to extend toward a front of the seat assembly and detach from the second limiting member in response to the seat unit being switched from the sitting position to the TV position.

According to an implementation, at least a part of the structure of the backrest assembly is configured to move forward following the seat frame, and a highest point of the backrest assembly has a tendency of moving downward and forward, in response to the seat frame sliding forward relative to the seat bracket. This leads to the seat unit not having high space requirements behind the backrest portion during installation, that is, the seat unit occupies a small amount of space behind the backrest portion during a position adjustment process.

Provided in a second aspect of the present disclosure is a seat, including the aforementioned seat unit. The position adjustment process is sequentially stable, leading to high comfort.

Provided in a third aspect of the present disclosure is a seat bracket, including a driving member and two mirror-symmetrically arranged and linked mechanical extension devices, where the mechanical extension device includes: a seat assembly including a seat bracket and a seat frame, the seat frame being disposed on the seat bracket and slidable relative to the seat bracket; a leg assembly adjustably and pivotally connected to the seat frame; a backrest assembly configured to be pivotally connected to both the seat frame and the seat bracket, wherein a pivot connection point between the backrest assembly and the seat frame is configured to move following the seat frame in response to the seat frame sliding relative to the seat bracket, a highest point of the backrest assembly is configured to have a tendency to move in a horizontal direction following movement of the seat frame; the highest point of the backrest assembly is configured to have a tendency to move downward approaching the ground in a longitudinal direction in response to the seat frame sliding forward relative to the seat bracket; the highest point of the backrest assembly is configured to have a tendency to move upward moving away from the ground in the longitudinal direction in response to the seat frame sliding rearward relative to the seat bracket; the driving member includes: a first driving unit disposed on the seat frame and configured to drive the leg assembly for position adjustment; a second driving unit disposed on the seat bracket and configured to drive the seat frame to slide relative to the seat bracket.

The tendency of movement exhibited by the highest point of the backrest assembly leads to the backrest portion mainly constituted by the backrest assembly exhibiting an overall trend of the lower end moving forward significantly and tilting backward in front-rear directions during a position adjustment process of the seat unit constituted by the seat bracket, specifically during switching from the TV position to the lying position, leading to the seat unit not having high space requirements behind the backrest portion during installation, that is, the seat unit occupies a small amount of space behind the backrest portion during the position adjustment process. During actual use, the seat unit is capable of being placed closer to a wall without affecting its position adjustment, saving space, when the backrest portion is placed facing the wall.

According to an implementation, the pivot connection point between the backrest assembly and the seat frame has a greater tendency to move forward than a tendency of the highest point of the backrest assembly to move forward in response to the seat frame sliding forward relative to the seat bracket.

According to an implementation, the backrest assembly includes an active rod, a first driven rod, a second driven rod, and a backrest mounting rod, wherein a lower end of the first driven rod and a lower end of the second driven rod are pivotally connected to the seat bracket respectively, an upper end of the first driven rod and an upper end of the second driven rod are pivotally connected to the backrest mounting rod respectively; a lower end of the active rod is pivotally connected to the seat frame, an upper end of the active rod is pivotally connected to any one of the first driven rod, the second driven rod, or the backrest mounting rod; a backrest plate is attached to the backrest mounting rod; a pivot connection point between the lower end of the active rod and the seat frame is configured to move following the seat frame in response to the seat frame sliding relative to the seat bracket.

According to an implementation, the backrest mounting rod includes a following portion and an attachment portion that are bent and connected, the first driven rod and the second driven rod are pivotally connected to the following portion respectively, and the backrest plate is attached to the attachment portion.

According to an implementation, the active rod includes a front rod and a rear rod connected to each other, wherein: the front rod is connected to the seat frame, and the rear rod is connected to the first driven rod; an extending direction of the front rod and an extending direction of the rear rod are set at an angle, so that the active rod is V-shaped with an opening facing upward.

According to an implementation, the front rod includes a first connecting portion and a first extension portion that are bent; the rear rod includes a second connecting portion and a second extension portion that are bent; the first extension portion is connected to the second extension portion, the first connecting portion is connected to the seat frame, and the second connecting portion is connected to the first driven rod; the first connecting portion is disposed closer to the seat frame than the first extension portion; the second connecting portion is disposed closer to the first driven rod than the second extension portion.

According to an implementation, the front rod and the rear rod are formed as a single piece.

According to an implementation, a limiting member, wherein the limiting member at least partially extends between the first driven rod and the second driven rod; the first driven rod abuts against the limiting member in response to the seat unit being in the sitting position and the TV position; the second driven rod abuts against the limiting member in response to the seat unit being in the lying position.

Provided in a fourth aspect of the present disclosure is a seat unit, including the aforementioned seat bracket. Low space is required behind the backrest portion during a backward tilting adjustment process of the backrest portion, facilitating arrangement and use of the seat unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of a seat unit in a sitting position according to Embodiment 1 of the present disclosure;

FIG. 2 is a schematic perspective view of the seat unit in the sitting position according to Embodiment 1 of the present disclosure;

FIG. 3 is a schematic front view of the seat unit in a TV position according to Embodiment 1 of the present disclosure;

FIG. 4 is a schematic perspective view of the seat unit in the TV position according to Embodiment 1 of the present disclosure;

FIG. 5 is a schematic front view of the seat unit in a lying position according to Embodiment 1 of the present disclosure;

FIG. 6 is a schematic perspective view of the seat unit in the lying position according to Embodiment 1 of the present disclosure;

FIG. 7 is a first schematic perspective view of a mechanical extension device with the seat unit in the lying position according to Embodiment 1 of the present disclosure;

FIG. 8 is a second schematic perspective view of the mechanical extension device with the seat unit in the lying position according to Embodiment 1 of the present disclosure;

FIG. 9 is a schematic perspective view of the mechanical extension device with the seat unit in the sitting position according to Embodiment 1 of the present disclosure;

FIG. 10 is a schematic assembly view of a seat frame and a seat bracket according to Embodiment 1 of the present disclosure;

FIG. 11 is a schematic exploded view of a first sliding rail member and a second sliding rail member according to Embodiment 1 of the present disclosure;

FIG. 12 is a schematic perspective view of a seat bracket in a sitting position according to Embodiment 2 of the present disclosure;

FIG. 13 is a schematic perspective view of the seat bracket in a TV position according to Embodiment 2 of the present disclosure;

FIG. 14 is a schematic perspective view of the seat bracket in a lying position according to Embodiment 2 of the present disclosure;

FIG. 15 is a first schematic perspective view of a mechanical extension device according to Embodiment 2 of the present disclosure;

FIG. 16 is a second schematic perspective view of the mechanical extension device according to Embodiment 2 of the present disclosure;

FIG. 17 is a schematic perspective view of a second driving unit driving a seat frame to slide relative to a seat bracket according to Embodiment 2 of the present disclosure;

FIG. 18 is a schematic perspective view of an active rod according to Embodiment 2 of the present disclosure.

100, mechanical extension device; 200, driving unit; 1, leg assembly; 11, following link; 12, drive link; 13, first extension link; 14, second extension link; 15, first limiting member; 16, footrest member; 17, transition link; 2, seat assembly; 201, first driving unit; 202, second driving unit; 21, seat frame; 210, supporting plate; 211, side plate; 212, second limiting member; 22, seat bracket; 221, first support; 222, second support; 23, first sliding rail member; 230, first base plate; 231, first outer side plate; 232, first inner side plate; 233, rounded surface; 24, second sliding rail member; 240, second base plate; 241, second inner side plate; 242, second outer side plate; 25, rolling member; 250, support member; 251, rolling body; 26, first seat plate; 27, second seat plate; 271, third limiting member; 281, first frame beam; 282, second frame beam; 283, hook; 29, seat plate; 291, limiting member; 3, backrest assembly; 31, active rod; 311, front rod; 3111, first connecting portion; 3112, first extension portion; 312, rear rod; 3121, second connecting portion; 3122, second extension portion; 32, first driven rod; 33, second driven rod; 34, backrest mounting rod; 341, following portion; 342, attachment portion; 4, first damping member; 5, second damping member; 6, backrest plate; 7, drive beam; 71, motor bracket; 8, fixed beam; 9, first fork bracket; 10, second fork bracket; a, first pivot point; b, second pivot point; c, third pivot point; d, fourth pivot point.

DETAILED DESCRIPTION

Embodiment 1

Please refer to FIGS. 1 to 6. A seat unit includes a pair of mirror-symmetrically arranged mechanical extension devices 100, a driving unit 200, and a first damping member 4. The two mechanical extension devices 100 are linked. The pair of linked mechanical extension devices constitutes a main structure of the seat unit. The seat unit is formed by attaching a seat portion (not shown in the figures), a footrest plate (not shown in the figures), and a backrest plate 6, and the like. The first damping member 4 cooperates with the driving unit 200 to achieve sequential adjustment of the mechanical extension device 100, thereby ensuring that the seat unit avoids disorder during the position adjustment process.

Specifically, the two mechanical extension devices 100 are linked. As shown in FIGS. 7 and 8, the mechanical extension device 100 includes a seat assembly 2 for attaching a seat portion, a leg assembly 1 adjustably assembled to a front end of the seat assembly 2, and a backrest assembly 3 adjustably assembled to a rear end of the seat assembly 2. The footrest plate is attached to the leg assembly 1, and the backrest plate 6 is attached to the backrest assembly 3. Optionally, the same footrest plate is attached to the two leg assemblies 1 of the two mechanical extension devices 100, and the same backrest plate 6 is attached to the two backrest assemblies 3 of the two mechanical extension devices 100.

In the present embodiment, the seat assembly 2 includes a seat frame 21 and a seat bracket 22 that are slidable relative to each other in front-rear directions of the seat assembly 2. The seat bracket 22 is fixed relative to the ground. The leg assembly 1 is pivotally connected to the seat frame 21. The backrest assembly 3 is configured to be pivotally connected to both the seat frame 21 and the seat bracket 22, and a pivot connection point between the backrest assembly 3 and the seat frame 21 is configured to move following the seat frame 21 in response to the seat frame 21 sliding relative to the seat bracket 22. In the present embodiment, the driving unit 200 is configured to drive the mechanical extension device 100, so that the seat unit is switched sequentially among a sitting position, a TV position, and a lying position, and the seat frame 21 slides relative to the seat bracket 22. Specifically, the seat frame 21 slides relative to the seat bracket 22 in response to the seat unit being switched from the sitting position to the lying position, or from the lying position to the sitting position.

As shown in FIGS. 4, 6, and 7, the first damping member 4 is disposed between the seat frame 21 and the seat bracket 22, wherein: the first damping member 4 is configured to obstruct the seat frame 21 from sliding relative to the seat bracket 22 toward a front of the seat assembly 2 in response to the seat unit being switched from the sitting position to the lying position; and the first damping member 4 is configured to drive the seat frame 21 to slide relative to the seat bracket 22 toward a rear of the seat assembly 2 in response to the seat unit being switched from the lying position to the sitting position. Such configuration leads to a high resistance for the seat frame 21 to slide relative to the seat bracket 22 toward a front of the seat assembly 2 under the action of the driving unit 200, and a low resistance for the seat frame 21 to slide relative to the seat bracket 22 toward a rear of the seat assembly 2, so as to cooperate with adjustment of the leg assembly 1 to ensure an adjustment sequence of a leg portion and a backrest portion of the seat unit.

In the present embodiment, the first damping member 4 leads to the seat frame 21 having a tendency to slide relative to the seat bracket 22 toward a rear of the seat assembly 2.

Optionally, the first damping member 4 is a tension spring or a rubber tube. In some implementations, the first damping member 4 is a tension spring. As shown in FIG. 7, a first seat plate 26 is disposed on the seat frame 21, a second seat plate 27 is disposed on the seat bracket 22, a front end of the tension spring is hooked to the first seat plate 26, and a rear end of the tension spring is hooked to the second seat plate 27. When the seat unit is in the sitting position and the TV position, there is no relative sliding between the seat frame 21 and the seat bracket 22, and the first damping member 4, i.e., the tension spring, is in a first stretched state. The first damping member 4, i.e., the tension spring, is further stretched to a second stretched state in response to the seat unit being switched from the TV position to the lying position.

In other embodiments, the first damping member 4 may also be disposed between the backrest assembly 3 and the seat bracket 22. In the present embodiment, the pivot connection point between the backrest assembly 3 and the seat frame 21 is configured to move following the seat frame 21, that is, in front-rear directions of the seat assembly 2, at least a part of the structure of the backrest assembly 3 is configured to move forward following the seat frame 21 sliding forward relative to the seat bracket 22 toward a front of the seat assembly 2, or move rearward following the seat frame 21 sliding rearward relative to the seat bracket 22 toward a rear of the seat assembly 2, so that the first damping member 4 acts on the seat frame 21 via the backrest assembly 3, leading to the seat frame 21 having a tendency to slide relative to the seat bracket 22.

In the present embodiment, at least a part of the structure of the backrest assembly 3 is configured to move forward following the seat frame 21, and a highest point of the backrest assembly 3 has a tendency of moving downward and forward, in response to the seat frame 21 sliding forward relative to the seat bracket 22. It should be noted that the tendency of the highest point of the backrest assembly 3 moving downward and forward does not exclude a temporary or small-distance rearward movement of the highest point of the backrest plate 6 or the backrest assembly 3 during this process. That is, the tendency of the highest point of the backrest assembly 3 moving downward and forward here is an overall tendency exhibited during the process of the seat frame 21 sliding forward relative to the seat bracket 22. Such movement tendency exhibited by the highest point of the backrest plate 6 or the backrest assembly 3 leads to the backrest portion, formed by the backrest assembly 3 attaching the backrest plate 6, exhibiting an overall trend in front-rear directions where a lower end thereof has a significant forward movement tendency and tilts backward during a position adjustment process of the seat unit, specifically during switching from the TV position to the lying position, leading to the seat unit not having high space requirements behind the backrest portion during installation, that is, the seat unit occupies a small amount of space behind the backrest portion during the position adjustment process. During actual use, the seat unit is capable of being placed closer to a wall without affecting its position adjustment, saving space, when the backrest portion is placed facing the wall.

Specifically, as shown in FIGS. 3 to 8, the backrest assembly 3 includes an active rod 31, a first driven rod 32, a second driven rod 33, and a backrest mounting rod 34, wherein: a lower end of the first driven rod 32 and a lower end of the second driven rod 33 are pivotally connected to the seat bracket 22 respectively, an upper end of the first driven rod 32 and an upper end of the second driven rod 33 are pivotally connected to the backrest mounting rod 34 respectively; a lower end of the active rod 31 is pivotally connected to the seat frame 21, an upper end of the active rod 31 is pivotally connected to any one of the first driven rod 32, the second driven rod 33, or the backrest mounting rod 34; a backrest plate 6 is attached to the backrest mounting rod 34. In the present embodiment, the lower end of the first driven rod 32 and the lower end of the second driven rod 33 are pivotally connected to a second seat plate 27 respectively. The first driven rod 32, the second seat plate 27, the second driven rod 33, and the backrest mounting rod 34 constitute a planar four-bar linkage. In some implementations, the upper end of the active rod 31 is pivotally connected to the first driven rod 32, and the first driven rod 32 is disposed on a side close to the leg assembly 1. A pivot connection point between the lower end of the active rod 31 and the seat frame 21 is configured to move following the seat frame 21 in response to the seat frame 21 sliding relative to the seat bracket 22. With such configuration, the backrest plate 6 mounted on the backrest mounting rod 34 is configured to have a lower end thereof follow the seat frame 21 to move forward and rearward while an upper end thereof basically does not move in front-rear directions (the upper end of the backrest plate 6 moves in up-down directions) in response to the seat frame 21 sliding relative to the seat bracket 22, that is, when the seat unit is switched between the TV position and the lying position, leading to adjustment of a backrest inclination angle of the seat unit and reducing a back-scrubbing sensation during use of the backrest in this process.

The first driven rod 32, the second seat plate 27, the second driven rod 33, and the backrest mounting rod 34 constitute a planar four-bar linkage, leading to stable and reliable structure and facilitating adjustment of an inclination angle of the backrest plate 6 or a backrest portion of the seat unit, or an adjustment speed of the backrest inclination angle, by adjusting dimensions of each side of the planar four-bar linkage to match a front-rear movement speed of the seat portion, thereby achieving a better purpose of reducing or even eliminating the back-scrubbing sensation.

In the present embodiment, a third limiting member 271 is disposed on the seat bracket 22 or the second seat plate 27, and the third limiting member 271 at least partially extends between the first driven rod 32 and the second driven rod 33. The first driven rod 32 abuts against the third limiting member 271 in response to the seat unit being in the sitting position and the TV position; the second driven rod 33 abuts against the third limiting member 271 in response to the seat unit being in the lying position. The third limiting member 271 herein is configured to assist in limiting the backrest assembly 3.

In some implementations, as shown in FIG. 7, a first damping surface is disposed on a side of the first driven rod 32 close to the second driven rod 33, a second damping surface is disposed on a side of the second driven rod 33 close to the first driven rod 32, and the first damping surface and the second damping surface are in frictional abutment. During adjustment of the backrest assembly 3, the first damping surface and the second damping surface slide relative to each other. Such configuration is capable of improving structural stability of the planar four-bar linkage structure, specifically, improving positional stability of the backrest mounting rod 34 during the adjustment process and repeatability of the position during multiple adjustments.

As shown in FIG. 8, the backrest mounting rod 34 includes a following portion 341 and an attachment portion 342 that are bent and connected. The first driven rod 32 and the second driven rod 33 are pivotally connected to the following portion 341 respectively. The backrest plate 6 is attached to the attachment portion 342.

In the present embodiment, the attachment portion 342 is located on an outer side of the following portion 341. This is for avoiding interference with the active rod 31.

In the present embodiment, the active rod 31 includes a front rod 311 and a rear rod 312 connected to each other, wherein the front rod 311 is connected to the seat frame 21, the rear rod 312 is connected to the first driven rod 32, and an extending direction of the front rod 311 and an extending direction of the rear rod 312 are set at an angle, so that the active rod 31 is V-shaped with an opening facing upward.

In some implementations, the front rod 311 includes a first connecting portion 3111 and a first extension portion 3112 that are bent. The first extension portion 3112 is connected to the rear rod 312, and the first connecting portion 3111 is connected to the seat frame 21. Specifically, the first extension portion 3112 is disposed closer to an inner side of the seat frame 21 compared to the first connecting portion 3111, thereby reducing a contact area between the front rod 311 and the seat frame 21 and reducing a possibility of interference between the front rod 311 and the seat frame 21.

In some implementations, the front rod 311 and the rear rod 312 are formed in a single piece.

In another embodiment, the backrest assembly 3 includes an active rod 31 and a driven rod that are pivotally connected, wherein: the active rod 31 is pivotally connected to the seat frame 21; the driven rod is pivotally connected to the seat bracket 22; a backrest plate 6 is attached to the active rod 31. In the present embodiment, the number of the active rod 31 and the driven rod is one each. An upper end of the active rod 31 and an upper end of the driven rod are pivotally connected, a lower end of the active rod 31 is pivotally connected to the seat frame 21, and a lower end of the driven rod is connected to the seat bracket 22. The lower end of the active rod 31 moves forward and rearward following the seat frame 21. During this process, the lower end of the active rod 31 moves forward and rearward at a speed faster than that of the upper end of the active rod 31. Therefore, the backrest plate 6 mounted on the active rod 31 is configured to achieve backward tilting angle adjustment following the active rod 31.

In the present embodiment, as shown in FIGS. 1 to 9, the seat unit further includes a second damping member 5. The second damping member 5 is disposed between the leg assembly 1 and the seat assembly 2. The second damping member 5 is configured to drive the leg assembly 1 to extend toward a front of the seat assembly 2 in response to the seat unit being switched from the sitting position to the lying position. The second damping member 5 is configured to obstruct the leg assembly 1 from retracting toward a rear of the seat assembly 2 in response to the seat unit being switched from the lying position to the TV position. The second damping member 5 herein leads to the leg assembly 1 being easier to extend forward in response to the seat unit being switched from the sitting position to the lying position, and the leg assembly 1 is subjected to a certain resistance in response to the seat unit being switched from the lying position to the TV position, cooperating with the first damping member 4 to maintain a stable position adjustment sequence for each part of the seat unit. That is, the leg assembly 1 or the leg portion is adjusted first to the TV position as shown in FIGS. 3 and 4, and then the backrest assembly 3 or the backrest portion begins adjusting to the lying position as shown in FIGS. 5 and 6, in response to the seat unit being adjusted from a closed state to an extended state. The backrest assembly 3 or the backrest portion is adjusted first to the TV position as shown in FIGS. 3 and 4, and then the leg assembly 1 or the leg portion is adjusted to the sitting position as shown in FIGS. 1 and 2, in response to the seat unit being adjusted from the extended state to the closed state. In some implementations, the second damping member 5 is disposed between the leg assembly 1 and the seat frame 21. In other embodiments, optionally, the second damping member 5 is disposed between the leg assembly 1 and the seat bracket 22.

In the present embodiment, the seat unit further includes a drive beam 7. The drive beam 7 is configured to link the leg assemblies 1 of the pair of mechanical extension devices 100. Specifically, as shown in FIGS. 7 and 8, the leg assembly 1 includes a drive link 12, a following link 11, a first extension link 13, a second extension link 14, and a footrest member 16, wherein: a first end of the drive link 12 and the following link 11 are both pivotally connected to the seat frame 21, a second end of the drive link 12 is pivotally connected to a first end of the first extension link 13, and the following link 11 is pivotally connected to a first end of the second extension link 14; a second end of the first extension link 13 and a second end of the second extension link 14 are pivotally connected to the footrest member 16, respectively; the drive link 12 is pivotally connected to the second extension link 14, and a pivot connection point therebetween is located between two ends of the second extension link 14; two ends of the drive beam 7 are connected to the corresponding drive links 12, respectively. In the present embodiment, the drive link 12 links the two leg assemblies 1 of the two mirror-symmetrically arranged mechanical extension devices 100. It should be noted that components of the leg assembly 1 directly connected to the drive beam 7 in the present embodiment may all be referred to as the “drive link 12”. The connection structure shown in the figures is exemplary or used in some implementations, following the principle of being capable of driving the leg assembly 1 to perform forward extension and backward retraction actions without causing spatial interference with other structural members. In other words, in other embodiments, if necessary, the drive beam 7 may also be assembled to the following link 11, the first extension link 13, or the second extension link 14, etc., in the present embodiment.

In the present embodiment, the leg assembly 1 may be any existing leg assembly 1 including the drive link 12, the following link 11, the first extension link 13, the second extension link 14, and the footrest member 16 described in the present embodiment.

In the present embodiment, the leg assembly 1 further includes a first limiting member 15. The first limiting member 15 is disposed on the second extension link 14. A pivot point between the second extension link 14 and the drive link 12 is defined as a first pivot point a. The first limiting member 15 is located between the first end of the second extension link 14 and the first pivot point a. During use, the drive link 12 abuts against the first limiting member 15 to maintain stability of the aforementioned three positions of the seat unit when the seat unit is in the sitting position, the TV position, and the lying position. The first limiting member 15 here is cylindrical in shape. Its cooperation with the drive link 12 and the following link 11 belongs to the prior art and is not repeated herein.

Optionally, the second damping member 5 is any one of a tension spring, a torsion spring, or a rubber tube. In some implementations, the second damping member 5 is a tension spring. In some implementations, as shown in FIG. 7, the second damping member 5 acts on the following link 11.

Specifically, a pivot point between the following link 11 and the seat frame 21 is defined as a second pivot point b. The second pivot point b is located between two endpoints of the following link 11, wherein one end of the following link 11 is pivotally connected to the second extension link 14, the other end of the following link 11 is pivotally connected to a front end of a transition link 17, and a front end of the second damping member 5 is hooked to a rear end of the transition link 17. Such configuration is capable of ensuring that the second damping member 5 extends substantially in front-rear directions throughout a position adjustment process of the seat unit, facilitating assembly and avoiding bending of the second damping member 5 due to rotation of the following link 11 after direct assembly with the following link 11, which would affect the lifespan of the second damping member 5.

In the present embodiment, an end of the following link 11 close to the backrest assembly 3 is bent toward an inner side of the seat frame 21 in the TV position. This is for preventing interference between the second damping member 5 and the seat frame 21.

In other embodiments, optionally, an end of the following link 11 away from the second extension link 14 is provided with a hanging shaft extending toward the inner side of the seat frame 21, and the second damping member 5, i.e., the tension spring, is hooked to the hanging shaft.

In other embodiments, a torsion spring is sleeved on a pivot shaft between the following link 11 and the seat frame 21. One end of the torsion spring abuts against the following link 11, and the other end abuts against the seat frame 21. It should be noted that the torsion spring stores energy and provides a resistance force to the leg assembly 1 in response to the leg assembly 1 retracting backward. The torsion spring releases energy and provides a driving force to the leg assembly 1 in response to the leg assembly 1 extending forward.

In the present embodiment, as shown in FIG. 9, a second limiting member 212 is disposed on the seat frame 21. The leg assembly 1 is configured to retract toward a rear of the seat assembly 2 and abut against the second limiting member 212 to maintain the sitting position in response to the seat unit being switched from the TV position to the sitting position. The leg assembly 1 is configured to extend toward a front of the seat assembly 2 and detach from the second limiting member 212 in response to the seat unit being switched from the sitting position to the TV position. Optionally, the second limiting member 212 is a cylindrical protrusion structure extending toward the inner side of the seat frame 21. The combined action of the first limiting member 15 and the second limiting member 212 is capable of ensuring structural stability of the seat unit when in the sitting position.

In the present embodiment, a pivot point between the drive link 12 and the seat frame 21 is defined as a third pivot point c, and the second pivot point b is disposed on a side close to the backrest assembly 3. That is, the second pivot point b is located behind the third pivot point c.

In the present embodiment, as shown in FIGS. 2, 4, and 6, the seat unit further includes a fixed beam 8, wherein: the fixed beam 8 is disposed between the seat brackets 22 of the pair of mechanical extension devices 100; the driving unit 200 is a telescoping member, a movable end of the telescoping member is pivotally connected to the drive beam 7, and a fixed end of the telescoping member is pivotally connected to the fixed beam 8. In some implementations, the telescoping member is a linear electric actuator.

In some implementations, as shown in FIG. 6, a motor bracket 71 is disposed on the drive beam 7, and the movable end of the telescoping member is pivotally connected to the motor bracket 71. A pivot point between the movable end of the telescoping member and the motor bracket 71 is defined as a fourth pivot point d, wherein the fourth pivot point d is behind the drive beam 7 in response to the seat unit being in the TV position and the lying position; the fourth pivot point d is below the drive beam 7 in response to the seat unit being in the sitting position. Such configuration is capable of moving a connection point between the telescoping member and the leg assembly 1 forward, leading to more favorable support for the leg assembly 1 and reducing a risk of the leg assembly 1 falling when the seat unit is in the TV position and the lying position.

In the present embodiment, a first sliding rail member 23 is disposed on the seat bracket 22, and a second sliding rail member 24 adapted to the first sliding rail member 23 is disposed on the seat frame 21; the first sliding rail member 23 and the second sliding rail member 24 are slidably connected.

In some implementations, as shown in FIGS. 10 and 11, the first sliding rail member 23 includes a first base plate 230, a first outer side plate 231 is disposed on each of two sides of the first base plate 230, a free end of the first outer side plate 231 is bent inward to form a first inner side plate 232, and the first base plate 230 is disposed on the seat bracket 22; the second sliding rail member 24 includes a second base plate 240, a second inner side plate 241 is disposed on each of two sides of the second base plate 240, a free end of the second inner side plate 241 is bent outward to form a second outer side plate 242, and the second base plate 240 is disposed on the seat frame 21; the second base plate 240 and the second inner side plates 241 disposed on the second base plate 240 are both located between the two first inner side plates 232, and the second outer side plates 242 are located between the corresponding first outer side plate 231 and first inner side plate 232; a rolling member 25 is disposed on the second outer side plate 242, and the rolling member 25 is in rolling abutment or sliding abutment with the first base plate 230 and/or the first outer side plate 231. The first base plate 230, the first outer side plate 231, and the first inner side plate 232 are formed in a single piece; the second base plate 240, the second inner side plate 241, and the second outer side plate 242 are formed in a single piece. A rounded surface 233 is configured on an inner side of a transitional connection portion between the first base plate 230 and the first outer side plate 231, and the rolling member 25 is in rolling abutment with the rounded surface 233.

In the present embodiment, the rolling member 25 includes a support member 250 disposed on the second outer side plate 242. A lower end of the support member 250 is provided with a rolling body 251 that is in rolling abutment or sliding abutment with the first base plate 230 and/or the first outer side plate 231. The rolling body 251 here is spherical in shape and is rotatably mounted to the lower end of the support member 250. During use, the rolling body 251 rolls at the rounded surface 233 along an extending direction of the first base plate 230 to achieve relative movement between the seat frame 21 and the seat bracket 22 in front-rear directions.

As shown in FIG. 10, the seat frame 21 includes a supporting plate 210. Side plates 211 are bent and disposed on two sides of the supporting plate 210. The second sliding rail member 24 is disposed on the supporting plate 210 and located between the two side plates 211. At least a part of the first sliding rail member 23 extends between the two side plates 211. In the present embodiment, the structures of the two side plates 211 may be the same or different, and are not specifically limited here. The structural design where at least a part of the first sliding rail member 23 extends between the two side plates 211 enables the side plates 211 to shield a gap between the first sliding rail member 23 and the second sliding rail member 24, leading to high safety.

In the present embodiment, the first seat plate 26 is disposed on the inner side plate 211 of the seat frame 21.

In the present embodiment, a first support 221 and a second support 222 are disposed on the seat bracket 22. The first support 221 is disposed on a side close to the leg assembly 1, and the second support 222 is disposed on a side close to the backrest assembly 3. The first support 221 and the second support 222 here are for cooperating with legs (not shown in the figures) to support and fix the seat bracket 22 on the ground.

As shown in FIGS. 2, 4, and 6, in the present embodiment, the seat unit further includes a first frame beam 281 and a second frame beam 282, wherein: a first end of the first frame beam 281 and a first end of the second frame beam 282 are both connected to the seat frame 21 of one of the mechanical extension devices 100; a second end of the first frame beam 281 and a second end of the second frame beam 282 are both connected to the seat frame 21 of the other mechanical extension device 100; the first frame beam 281 is disposed on a side close to the leg assembly 1, and the second frame beam 282 is disposed on a side close to the backrest assembly 3. In some implementations, a plurality of hooks 283 are correspondingly and integrally stamped on the first frame beam 281 and the second frame beam 282, respectively; the seat unit further includes a sinuous spring (not shown in the figures), one end of the sinuous spring is hooked on the hooks 283 of the first frame beam 281, and the other end of the sinuous spring is hooked on the corresponding hooks 283 of the second frame beam 282. The sinuous spring here serves as a skin of the seat unit, has good damping effect, and effectively improves comfort of the seat unit. In the present embodiment, the structures of the sinuous spring, the seat frame 21, the first frame beam 281, and the second frame beam 282 may refer to a sofa seat frame disclosed in a Chinese patent with publication number CN212117668U, wherein the seat frame 21 corresponds to a longitudinal beam in the prior art, the first frame beam 281 and the second frame beam 282 correspond to transverse beams in the prior art, and the sinuous spring corresponds to a supporting elastic member in the prior art. Their specific structures and working principles are not repeated herein.

The present embodiment further provides a seat, including the aforementioned seat unit. The position adjustment process of the seat is sequentially stable, leading to high comfort.

Embodiment 2

Please refer to FIGS. 12 to 18. A seat bracket includes a driving unit 200 and two mirror-symmetrically arranged and linked mechanical extension devices 100. The mechanical extension device 100 is connected to a seat assembly 2 of a seat portion, a leg assembly 1 attaching a footrest, and a backrest assembly 3 attaching a backrest plate 6. The seat assembly 2 includes a seat bracket 22 and a seat frame 21. The seat frame 21 is disposed on the seat bracket 22 and is slidable relative to the seat bracket 22. The leg assembly 1 is adjustably and pivotally connected to the seat frame 21. The backrest assembly 3 is configured to be pivotally connected to both the seat frame 21 and the seat bracket 22. A pivot connection point between the backrest assembly 3 and the seat frame 21 is configured to move following the seat frame 21 in response to the seat frame 21 sliding relative to the seat bracket 22. A highest point of the backrest assembly 3 is configured to have a tendency to move in a horizontal direction following movement of the seat frame 21. The highest point of the backrest assembly 3 is configured to have a tendency to move downward approaching the ground in a longitudinal direction in response to the seat frame 21 sliding forward relative to the seat bracket 22. The highest point of the backrest assembly 3 is configured to have a tendency to move upward moving away from the ground in the longitudinal direction in response to the seat frame 21 sliding rearward relative to the seat bracket 22.

It should be noted that the tendency of the highest point of the backrest assembly 3 moving downward approaching the ground in the longitudinal direction (moving downward) and moving forward in the horizontal direction in response to the seat frame 21 sliding forward relative to the seat bracket 22 does not exclude a temporary or small-distance rearward movement of the highest point of the backrest plate 6 or the backrest assembly 3 during this process. That is, the tendency of the highest point of the backrest assembly 3 moving downward and forward here is an overall tendency exhibited during the process of the seat frame 21 sliding forward relative to the seat bracket 22. Such movement tendency exhibited by the highest point of the backrest plate 6 or the backrest assembly 3 leads to the backrest portion, formed by the backrest assembly 3 attaching the backrest plate 6, exhibiting an overall trend in front-rear directions where a lower end thereof has a significant forward movement tendency and tilts backward during a position adjustment process of a seat unit constituted by the seat bracket, specifically during switching from a TV position to a lying position, leading to the seat unit not having high space requirements behind the backrest portion during installation, that is, the seat unit occupies a small amount of space behind the backrest portion during the position adjustment process. During actual use, the seat unit is capable of being placed closer to a wall without affecting its position adjustment, saving space, when the backrest portion is placed facing the wall.

In some implementations, the driving unit 200 includes a first driving unit 201 and a second driving unit 202. The first driving unit 201 is disposed on the seat frame 21 and configured to drive the leg assembly 1 for position adjustment. The second driving unit 202 is disposed on the seat bracket 22 and configured to drive the seat frame 21 to slide relative to the seat bracket 22. The first driving unit 201 and the second driving unit 202 here may both be linear actuators. The first driving unit 201 and the second driving unit 202 operate independently and are configured to drive the seat bracket to achieve position adjustment. Specifically, as shown in FIGS. 12 to 14, the first driving unit 201 drives the leg assembly 1 to extend forward so that the seat bracket is switched from the sitting position shown in FIG. 12 to the TV position shown in FIG. 13. In some implementations, the second driving unit 202 drives the seat frame 21 to slide forward relative to the seat bracket 22 so that the seat bracket is switched from the TV position in FIG. 13 to the lying position shown in FIG. 14.

In the present embodiment, as shown in FIGS. 12 to 17, the two mirror-symmetrically arranged mechanical extension devices 100 are linked. Specifically, the seat bracket further includes a drive beam 7, a fixed beam 8, a first frame beam 281, and a second frame beam 282, wherein a first end of the first frame beam 281 and a first end of the second frame beam 282 are connected to the seat frame 21 of one mechanical extension device 100, and a second end of the first frame beam 281 and a second end of the second frame beam 282 are connected to the seat frame 21 of the other mechanical extension device 100, for connecting the seat frames 21 of the two mirror-symmetrically arranged mechanical extension devices 100 as an integral unit to achieve linkage between them. One end of the drive beam 7 is connected to the leg assembly 1 of one mechanical extension device 100, and the other end of the drive beam 7 is connected to the leg assembly 1 of the other mechanical extension device 100, thereby linking the leg assemblies 1 of the two mirror-symmetrically arranged mechanical extension devices 100. A first end of the fixed beam 8 is connected to the seat bracket 22 of one mechanical extension device 100, and the other end is connected to the seat bracket 22 of the other mechanical extension device 100, for fixedly connecting the seat brackets 22 of the two mirror-symmetrically arranged mechanical extension devices 100 to improve structural stability of the seat bracket. In some implementations, the first frame beam 281 is disposed on a side close to the leg assembly 1, and the second frame beam 282 is disposed on a side close to the backrest assembly 3.

In the present embodiment, the first driving unit 201 is installed between the second frame beam 282 and the drive beam 7, and the second driving unit 202 is installed between the second frame beam 282 and the fixed beam 8.

In some implementations, a first fork bracket 9 is disposed on the second frame beam 282, a second fork bracket 10 is disposed on the fixed beam 8, a fixed portion of the second driving unit 202 is pivotally connected to the second fork bracket 10, a pivot shaft therebetween is a first shaft, a telescoping portion of the second driving unit 202 is connected to the first fork bracket 9, a connection point therebetween is a first connection point, and a minimum distance between the first connection point and the first shaft is smaller than a minimum distance between the second frame beam 282 and the fixed beam 8. Such configuration is capable of reducing a driving length or assembly length of the second driving unit 202 between the second frame beam 282 and the fixed beam 8, facilitating improvement of structural rigidity of the second driving unit 202 and improving safety of the seat bracket.

To reduce a back-scrubbing sensation of the seat bracket, in the present embodiment, the pivot connection point between the backrest assembly 3 and the seat frame 21 has a greater tendency to move forward than a tendency of the highest point of the backrest assembly 3 to move forward in response to the seat frame 21 sliding forward relative to the seat bracket 22.

Specifically, as shown in FIGS. 14 and 15, the backrest assembly 3 includes an active rod 31, a first driven rod 32, a second driven rod 33, and a backrest mounting rod 34, wherein: a lower end of the first driven rod 32 and a lower end of the second driven rod 33 are pivotally connected to the seat bracket 22 respectively, an upper end of the first driven rod 32 and an upper end of the second driven rod 33 are pivotally connected to the backrest mounting rod 34 respectively; a lower end of the active rod 31 is pivotally connected to the seat frame 21, an upper end of the active rod 31 is pivotally connected to any one of the first driven rod 32, the second driven rod 33, or the backrest mounting rod 34; a backrest plate 6 is attached to the backrest mounting rod 34; a pivot connection point between the lower end of the active rod 31 and the seat frame 21 is configured to move following the seat frame 21 in response to the seat frame 21 sliding relative to the seat bracket 22.

Specifically, to facilitate assembly of the first driven rod 32 and the second driven rod 33 with the seat bracket 22, in some embodiments, a seat plate 29 is disposed on the seat bracket 22, and the first driven rod 32 and the second driven rod 33 are pivotally connected to the seat plate 29. In the present embodiment, the seat plate documentation. 29 may also be disposed at a position on the fixed beam 8 close to the seat bracket 22 since the fixed beam 8 and the seat bracket 22 are fixedly connected. The seat plate 29 and the seat bracket 22 or the fixed beam 8 may be connected by bolts or by welding. When welded, the seat plate 29 may be considered as part of the seat bracket 22, or the seat plate 29 may be considered as part of the fixed beam 8.

A lower end of the first driven rod 32 and a lower end of the second driven rod 33 are pivotally connected to the seat plate 29 respectively. The first driven rod 32, the seat plate 29, the second driven rod 33, and the backrest mounting rod 34 constitute a planar four-bar linkage. In some implementations, the upper end of the active rod 31 is pivotally connected to the first driven rod 32, and the first driven rod 32 is disposed on a side close to the leg assembly 1. A pivot connection point between the lower end of the active rod 31 and the seat frame 21 is configured to move following the seat frame 21 in response to the seat frame 21 sliding relative to the seat bracket 22. With such configuration, the backrest plate 6 mounted on the backrest mounting rod 34 is configured to have a lower end thereof follow the seat frame 21 to move forward and rearward while an upper end thereof basically does not move in front-rear directions (the upper end of the backrest plate 6 mainly exhibits movement in up-down directions) in response to the seat frame 21 sliding relative to the seat bracket 22, that is, when the seat unit is switched between the TV position and the lying position, leading to adjustment of a backrest inclination angle of the seat unit and reducing a back-scrubbing sensation during use of the backrest in this process.

As shown in FIG. 16, in the present embodiment, the backrest mounting rod 34 includes a following portion 341 and an attachment portion 342 that are bent and connected. The first driven rod 32 and the second driven rod 33 are pivotally connected to the following portion 341 respectively. The backrest plate 6 is attached to the attachment portion 342. In the present embodiment, the attachment portion 342 is located on an outer side of the following portion 341. In some implementations, the active rod 31 includes a front rod 311 and a rear rod 312 connected to each other, wherein the front rod 311 is connected to the seat frame 21, the rear rod 312 is connected to the first driven rod 32, and an extending direction of the front rod 311 and an extending direction of the rear rod 312 are set at an angle, so that the active rod 31 is V-shaped with an opening facing upward.

In some implementations, the front rod 311 includes a first connecting portion 3111 and a first extension portion 3112 that are bent; the rear rod 312 includes a second connecting portion 3121 and a second extension portion 3122 that are bent; the first extension portion 3112 is connected to the second extension portion 3122, the first connecting portion 3111 is connected to the seat frame 21, and the second connecting portion 3121 is connected to the first driven rod 32; the first connecting portion 3111 is disposed closer to the seat frame 21 than the first extension portion 3112; the second connecting portion 3121 is disposed closer to the first driven rod 32 than the second extension portion 3122. Therefore, a contact area between the front rod 311 and the seat frame 21 may be reduced, reducing a possibility of interference between the front rod 311 and the seat frame 21; simultaneously, a contact area between the rear rod 312 and the first driven rod 32 may be reduced, reducing a possibility of interference between the rear rod 312 and the first driven rod 32.

In the present embodiment, in some implementations, the front rod 311 and the rear rod 312 are integrally formed.

In the present embodiment, a limiting member 291 is disposed on the seat bracket 22 or the seat plate 29, and the limiting member 291 at least partially extends between the first driven rod 32 and the second driven rod 33. The first driven rod 32 abuts against the limiting member 291 in response to the seat unit being in the sitting position and the TV position; the second driven rod 33 abuts against the limiting member 291 in response to the seat unit being in the lying position. The limiting member 291 herein is configured to assist in limiting the backrest assembly 3.

The present embodiment further provides a seat unit, including the aforementioned seat bracket. Low space is required behind the backrest portion during a backward tilting adjustment process of the backrest portion, facilitating arrangement and use of the seat unit.