A kind of seat

Abstract

The invention discloses a seat, comprising a backrest, a seat, a footrest, an armrest and a mechanical extension device installed between the armrests, the mechanical extension device comprising an actuator for driving the mechanical extension unit to move, the mechanical extension unit comprising: a transmission connecting rod, a backrest connecting piece, a seat connecting piece and a footstool connecting piece; the transmission connecting rod is rotatably connected to the base, and the actuator acts on the transmission connecting rod; the backrest connecting piece is connected to the backrest; the footstool connecting piece is connected to the footrest; the seat connecting piece is connected to the seat, and the seat connecting piece is rotatably connected to the seat connecting rod; the seat comprises four states: auxiliary standing, normal sitting, extending the footrest, and lying, and all are adjusted and controlled by the actuator; when switching from normal sitting to auxiliary standing, the actuator extends forward and drives the transmission connecting rod to swing upward, the lifting piece on the transmission connecting rod lifts the seat connecting piece, and the rear part of the seat connecting piece swings upward; when the seat is in the auxiliary standing state, the rear part of the seat is left empty.

Description

Technical Field

[0001] The invention relates to the field of furniture, in particular to a seat. Background Art

[0002] Seats are one of the most common furniture. With the improvement of people's quality of life, simple sitting functions are gradually unable to meet the pursuit of modern people's comfort in seating. Therefore, many seats and sofas have added footrests and lying functions. Some manufacturers have invented a sofa that can assist standing up for the elderly and other people with limited mobility, while also retaining the footrest and lying functions, which are excellent in both practicality and comfort. Although the functions meet the needs of many people with limited mobility, due to the large size, complex structure and heavy weight of its mechanical extension device, it can only be installed in the sofa, and it is difficult for a normal person to carry or move it, and it is easy to leave scratches on the floor. Two sets of electric push rods are usually required to realize the footrest, lying and standing assistance functions, and the difficulty and cost of production and assembly by manufacturers are high. The complex production and assembly process consumes a lot of manpower, material resources and time, and has a high cost of packaging and transportation.

[0003] The Chinese invention patent with the patent number CN201510452057.X discloses an electric chair for the elderly, including a base frame, on which are mounted a footrest extension mechanism, a backrest reclining mechanism, an auxiliary standing mechanism, a cushion lifting mechanism and a connecting rod transmission mechanism, the auxiliary standing mechanism being mounted on both sides of the base frame, each of which is correspondingly equipped with a set of cushion lifting mechanisms; each set of cushion lifting mechanisms is equipped with a set of footrest lifting mechanisms; the connecting rod transmission mechanism connects the footrest lifting mechanism and the backrest reclining mechanism. The chair has a complex structure and a large number of connecting rods. When assisting in standing, the entire mechanical extension device is almost lifted by the lifting of the electric push rod, which has poor stability and high requirements for the performance and strength of the electric push rod.

[0004] The Chinese invention patent with the patent number CN201710463006.6 discloses a dual-motor liftable elderly chair, including a base frame, a seat lifting mechanism, a back telescopic mechanism, and a leg telescopic mechanism. The seat lifting mechanism is arranged on the base frame, and the back telescopic mechanism and the leg telescopic mechanism are arranged on the seat lifting mechanism. The chair uses a set of electric push rods to realize the auxiliary standing function, and another set of electric push rods is used to realize the back telescopic mechanism and the leg telescopic mechanism. It is large in size, complex in structure, and high in cost.

[0005] Therefore, there is an urgent need for a mechanical extension device with a simple structure and small size, which can achieve the function of assisting the elderly chair to stand up and realize the function of resting feet and lying down through a set of electric push rods to solve the above problems. Summary of the invention

[0006] In order to solve the above-mentioned technical problems, the present invention provides a seat, which is driven by an internal mechanical extension device to switch between four states: normal sitting, assisted standing, extended footrest and lying. The lifting part on the transmission connecting rod rotates upward with the transmission connecting rod to lift the seat connecting part, so that the seat is flipped forward to achieve assisted standing. The mechanical extension device has a small number of connecting rods and only a single actuator is needed to complete the above work. Therefore, the seat has a simple structure and a small size, lower cost but higher reliability.

[0007] The technical solution of the present invention is achieved in this way:

[0008] A seat, comprising:

[0009] a backrest configured to support a human back;

[0010] a seat portion configured to support a buttocks of a human body;

[0011] The footrest is configured to be folded under the seat when the footrest is retracted, and to support the legs of the human body when the footrest is extended;

[0012] two armrests located on the left and right sides of the backrest and the seat, the armrests being configured to support human arms;

[0013] A mechanical extension device is suspended between two armrests; the mechanical extension device comprises a base, a mechanical extension unit mirror-imaged on both sides of the base, and an actuator for driving the mechanical extension unit, wherein the mechanical extension unit comprises a transmission connecting rod, a backrest connecting member, a seat connecting member, and a footrest connecting member; the left and right sides of the base are fixedly connected to the two armrests; the actuator is hinged to the base and acts on the transmission connecting rod; the transmission connecting rod is rotatably connected to the base, and one end of the actuator is rotatably connected to the transmission connecting rod; the backrest connecting member is fixedly connected to the backrest, and the backrest connecting member is transmission-connected to the transmission connecting rod through a backrest connecting rod assembly; the footrest connecting member is fixedly connected to the footrest, and the footrest connecting member is transmission-connected to the transmission connecting rod through a footrest connecting rod assembly; the seat connecting member is fixedly connected to the seat, and the seat connecting member is rotationally connected to the seat connecting rod;

[0014] A cylindrical lifting member is provided on the transmission connecting rod, and the lifting member is located in front of the rotation connection point between the transmission connecting rod and the base and in the rear and lower part of the connection point between the seat connecting member and the seat connecting rod;

[0015] The seat comprises four states: assisted standing, normal sitting, extended footrest and lying; the four states are all adjusted and controlled by the actuator; when switching from normal sitting to assisted standing, the actuator extends forward and drives the transmission connecting rod to swing forward and upward, the lifting part lifts the seat connecting part, the rear part of the seat connecting part swings upward, and drives the seat to swing synchronously; when the seat is in the assisted standing state, the rear part of the seat is left empty.

[0016] Assisted standing is achieved by lifting the seat connecting part through the jacking piece, which only lifts the rear part of the seat into the air instead of lifting the entire mechanical extension device or the entire seat, which greatly reduces the requirements for the actuator; using a single actuator allows the seat to switch between four states: normal sitting, assisted standing, extended footrest and lying, which is more reasonable in structure and saves the cost of actuator; the movement of the seat, footrest and backrest are interconnected through the connecting rod mechanism of the mechanical extension device, and the function of switching the seat between different states is achieved with the least possible number of connecting rods, which simplifies the structure and reduces the overall weight and volume, facilitates production and assembly, handling, packaging and transportation, and can install the mechanical extension device in smaller seats; due to the reduction in the number of connecting rods, the constraints between the connecting rods are strengthened, the movement of each connecting rod can be effectively restricted, so that the certainty of the connecting rod movement trajectory is improved, which makes the reliability of the seat better when working.

[0017] Preferably, the rotation point of the seat is located at the front end of the seat. The existing mechanical extension device with the assisting standing function is almost entirely lifted, which will push the center of gravity of the human body forward and upward, while in the present invention, the rotation point of the seat is close to the human knee joint, which lifts the human hips to rotate the knee joint to assist the user to stand, which is more ergonomic.

[0018] Preferably, when the seat is in the assisted standing state, the seat is tilted forward to form an angle of 28° with the horizontal plane.

[0019] Preferably, a seat return spring is provided between the seat connector and the seat connecting rod, and the seat return spring is configured to impart a force to the rear portion of the seat connector to rotate downward.

[0020] Preferably, a supporting plate is provided on the seat connecting rod, and a limiting plate is correspondingly provided on the seat connecting member. When the seat is in the auxiliary standing state, the limiting plate is separated from the supporting plate. In the normal sitting, stretching footrest and lying state, the limiting plate is supported on the supporting plate by the seat return spring. The position and state of the seat connecting member are determined by the spring, the lifting member, the limiting plate and the supporting plate. At each stroke position of the actuator, the position and state of the seat connecting member are determined and can be stably maintained.

[0021] Preferably, the seat connecting member is provided with a first seat mounting plate and a second seat mounting plate for mounting the seat, the first seat mounting plate is located in front of the second seat mounting plate, the rear portion of the first seat mounting plate is bent downward to form an engaging plate for engaging with the lifting member, the lifting member is located below the engaging plate, when the seat is switched from normal sitting to assisted standing, the lifting member lifts the engaging plate upward and drives the rear portion of the seat connecting member to swing upward.

[0022] Preferably, a transversely arranged square tube is provided between the transmission connecting rods on the left and right sides, the square tube is fixedly connected to the transmission connecting rods on the left and right sides and is rotatably connected to the actuator; the transmission connecting rod is a plate-shaped member, including a connecting end connected to the square tube, a rotating shaft end rotatably connected to the base, and a lifting end provided with a lifting member, the lifting end is located in front of the rotating shaft end and the connecting end, and the connecting end is located below the rotating shaft end and the lifting end; a first transmission point and a second transmission point are provided between the rotating shaft end and the lifting end, a first push-pull rod for lifting the seat connecting rod is rotatably connected at the first transmission point, and a push-pull rod for driving the backrest is rotatably connected at the second transmission point. The second push-pull rod of the connecting piece moves; when the seat switches from the normal sitting state to the auxiliary standing state, the transmission connecting rod drives the first and second push-pull rods to move forward, the first push-pull rod first drives the seat connecting rod to move downward and forward and then drives the seat connecting rod back to its original position, and the second push-pull rod drives the backrest connecting piece and the backrest to tilt forward; when the seat switches from the normal sitting state to the extended footrest state or lying state, the actuator retracts and drives the transmission connecting rod to rotate downward and backward, the transmission connecting rod drives the first and second push-pull rods to move backward, the first push-pull rod lifts the seat connecting rod upward and backward, and the second push-pull rod drives the backrest connecting piece and the backrest to lean back. The transmission connecting rod is used to link the various components of the seat, and a single actuator can be used to achieve the switching of all states of the seat.

[0023] Preferably, a lifting link is rotatably provided on the base, the rear end of the lifting link is rotatably connected to the base, and the front end of the lifting link is rotatably connected to the seat link; a first push-pull rod is rotatably provided on the transmission link, and the front end of the first push-pull rod is rotatably connected to the lifting link; when the transmission link is driven by the actuator to rotate backward, it drives the first push-pull rod to move backward, the first push-pull rod pulls the lifting link backward, the front end of the lifting link rotates upward and backward, and the seat link is lifted upward and backward.

[0024] Preferably, the rear end of the seat connecting rod is rotatably connected to a driven connecting rod, which is rotatably connected to the base. The driven connecting rod is configured to support the seat connecting rod and keep the seat approximately horizontal.

[0025] Preferably, the backrest connecting rod assembly includes a second push-pull rod, a first backrest connecting rod and a second backrest connecting rod, the first and second backrest connecting rods are both rotatably connected to the base and the first backrest connecting rod is located in front of the second backrest connecting rod; the front end of the second push-pull rod is rotatably connected to the transmission connecting rod, and the rear end of the second push-pull rod is rotatably connected to the first backrest connecting rod; the upper ends of the first backrest connecting rod and the second backrest connecting rod are both rotatably connected to the backrest connecting member; when the actuator retracts and drives the transmission connecting rod to rotate backward, the seat connecting rod is lifted upward and backward, and the seat is lifted upward and backward accordingly, the second push-pull rod moves backward and drives the upper end of the first backrest connecting rod to rotate forward, so that the backrest connecting member drives the second backrest connecting rod to rotate forward and downward, and the backrest moves forward while tilting backward, and the lower part of the backrest and the rear part of the seat are close to each other. When the backrest tilts backward, the backrest and the seat are close to each other, so that the buttocks and waist and back of the human body remain relatively still, thereby realizing the function of preventing back rubbing and waist running.

[0026] Preferably, the footstool connecting rod assembly is rotatably connected to the front end of the seat connecting rod, and a footstool push-pull rod is further provided between the footstool connecting rod assembly and the base, the rear end of the footstool push-pull rod is rotatably connected to the base, and the front end of the footstool push-pull rod is rotatably connected to the footstool connecting rod assembly; when the seat is switched from the auxiliary standing state to the extended footrest state, the actuator retracts, so that the seat first returns to the normal sitting state from the auxiliary standing state, and the actuator continues to retract to drive the transmission connecting rod to rotate backward, and the transmission connecting rod drives the first and second push-pull rods to move backward, the first push-pull rod pulls the lifting connecting rod backward, the front end of the lifting connecting rod rotates upward and backward, and the seat connecting rod and the footstool connecting rod assembly are lifted upward and backward, and the front end of the footstool push-pull rod rotates upward accordingly and pushes the footstool connecting rod assembly to extend the footstool connecting rod assembly forward, and the footstool connecting member and the footrest are also extended accordingly; the second push-pull rod causes the backrest connecting member and the backrest to move forward while tilting backward. The footrest of the seat can lift the user's legs and enable the user to lean back in a sitting position.

[0027] Preferably, when the seat switches from the extended footrest state to the lying state, the actuator continues to retract to the shortest state, the footrest is in a fully extended state, the lower end of the backrest is in contact with the rear end of the seat, and the backrest is reclined to 145 degrees. When the seat is in the lying state, the user can lie on the seat with the legs supported by the footrest.

[0028] The design starting point, concept and beneficial effects of the present invention using the above technical solution are:

[0029] Assisted standing is achieved by lifting the seat connecting part through the jacking piece, which only lifts the rear part of the seat into the air instead of lifting the entire mechanical extension device or the entire seat, which greatly reduces the requirements for the actuator; using a single actuator allows the seat to switch between four states: normal sitting, assisted standing, extended footrest and lying, which is more reasonable in structure and saves the cost of actuator; the movement of the seat, footrest and backrest are interconnected through the connecting rod mechanism of the mechanical extension device, and the function of switching the seat between different states is achieved with the least possible number of connecting rods, which simplifies the structure and reduces the overall weight and volume, facilitates production and assembly, handling, packaging and transportation, and can install the mechanical extension device in smaller seats; due to the reduction in the number of connecting rods, the constraints between the connecting rods are strengthened, the movement of each connecting rod can be effectively restricted, so that the certainty of the connecting rod movement trajectory is improved, which makes the reliability of the seat better when working. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The three-dimensional structure of the seat in the embodiment of the present invention in the normal sitting state is shown in FIG. Figure 1 ;

[0031] Figure 2 The three-dimensional structure of the seat in the embodiment of the present invention in the normal sitting state is shown in FIG. Figure 2 ;

[0032] Figure 3 The three-dimensional structure of the mechanical extension device in the normal sitting state of the embodiment of the present invention is shown in FIG. Figure 1 ;

[0033] Figure 4 The three-dimensional structure of the mechanical extension device in the normal sitting state of the embodiment of the present invention is shown in FIG. Figure 2 ;

[0034] Figure 5 It is a schematic diagram of the three-dimensional structure of the connection between the seat, the backrest and the mechanical extension device in the embodiment of the present invention;

[0035] Figure 6 A side view of the mechanical extension unit in a normal sitting state in an embodiment of the present invention;

[0036] Figure 7 It is a schematic diagram of the three-dimensional structure of the seat in the embodiment of the present invention in the auxiliary standing state;

[0037] Figure 8 It is a schematic diagram of the three-dimensional structure of the mechanical stretching device in the auxiliary standing state in an embodiment of the present invention;

[0038] Fig. 9 A side view of the mechanical extension unit in the auxiliary standing state in an embodiment of the present invention;

[0039] Fig.10 It is a schematic diagram of the three-dimensional structure of the transmission connecting rod connected to the square tube in the embodiment of the present invention;

[0040] Fig.11 It is a side view of a four-bar linkage mechanism for seat link movement in an embodiment of the present invention;

[0041] Fig.12 for Fig.11 Schematic diagram of the motion principle of the four-bar linkage mechanism of the middle seat link movement;

[0042] Fig.13 A side view of a four-bar linkage mechanism for driving the seat connecting rod to move in an embodiment of the present invention;

[0043] Fig.14 for Fig.13 Schematic diagram of the motion principle of the four-bar linkage mechanism that drives the seat connecting rod;

[0044] Fig.15 It is a schematic diagram of the three-dimensional structure of the seat in the embodiment of the present invention in the extended footrest state;

[0045] Fig.16 It is a schematic diagram of the three-dimensional structure of the mechanical extension device in the extended footrest state in the embodiment of the present invention;

[0046] Fig.17 A side view of the mechanical extension unit in the embodiment of the present invention when the footrest is extended;

[0047] Fig.18 A side view of a link mechanism for the movement of the first footrest link in an embodiment of the present invention;

[0048] Fig.19 for Fig.18 Schematic diagram of the motion principle of the linkage mechanism for the motion of the first footrest link;

[0049] Fig. 20 It is a schematic diagram of the three-dimensional structure of the seat in the embodiment of the present invention in a lying state;

[0050] Fig.21 It is a schematic diagram of the three-dimensional structure of the mechanical stretching device in a lying state in an embodiment of the present invention;

[0051] Fig. 22 A side view of the mechanical extension unit in a lying state in an embodiment of the present invention;

[0052] Fig.23 A side view of a four-bar linkage mechanism for driving the backrest connecting member to move in an embodiment of the present invention;

[0053] Fig.24 for Fig.23Schematic diagram of the motion principle of the four-bar linkage that drives the backrest connection member to move;

[0054] Fig.25 A side view of a four-bar linkage mechanism for moving a backrest connecting member in an embodiment of the present invention;

[0055] Fig.26 for Fig.25 Schematic diagram of the kinematic principle of the four-bar linkage for the movement of the middle backrest connecting member;

[0056] Fig. 27 This is a schematic diagram of the seat in the embodiment of the present invention in a normal sitting state;

[0057] Fig.28 It is a schematic diagram of the state of the seat in the embodiment of the present invention in the auxiliary standing state;

[0058] Fig.29 It is a schematic diagram of the state of the seat in the embodiment of the present invention when the footrest is extended;

[0059] Fig.30 It is a schematic diagram of the state of the seat in the embodiment of the present invention in the lying state.

[0060] The reference numerals of the drawings are: backrest 1; seat 2; armrest 3; mechanical extension device 4; base 5; mechanical extension unit 4a; actuator 6; transmission link 7; connection end 7a; shaft end 7b; lifting end 7c; first transmission point 7d; second transmission point 7e; backrest connector 8; seat connector 9; footstool connector 10; square tube 11; seat connector 12; lifting member 13; first push-pull rod 14; lifting link 15; footstool push-pull rod 16; first footstool connector 17; second Footrest connecting rod 18; third footrest connecting rod 19; fourth footrest connecting rod 20; fifth footrest connecting rod 21; second push-pull rod 22; first backrest connecting rod 23; second backrest connecting rod 24; driven connecting rod 25; seat return spring 26; first spring fixing column 27; connecting ear 28; supporting plate 29; limiting plate 30; first seat mounting plate 31; second seat mounting plate 32; catering plate 33; second spring fixing column 34; third spring fixing column 35; footrest return spring 36. DETAILED DESCRIPTION

[0061] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0063] In the description of the present invention, the term "at least one" refers to one or more than one, unless otherwise clearly defined. The terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0064] The specific implementation of the present invention is as follows:

[0065] like Figure 1 , 2 As shown, the present invention provides a kind of sitting furniture, comprising a backrest 1, a seat 2, a footrest (not shown), two armrests 3 located on the left and right sides of the backrest 1 and the seat 2, and a mechanical extension device 4 suspended between the two armrests 3; the backrest 1 is configured to support the back of a human body, the seat 2 is configured to support the buttocks of a human body, the footrest is configured to be folded under the seat 2 when the footrest is contracted, and to support the legs of a human body when the footrest is extended, and the armrest 3 is configured to support the arms of a human body.

[0066] like Figure 2-6 As shown, the mechanical extension device 4 includes a base 5, a mechanical extension unit 4a mirror-mounted on both sides of the base 5, and an actuator 6 for driving the mechanical extension unit 4a. The actuator 6 is an electric push rod. The mechanical extension unit 4a includes: a transmission connecting rod 7, a backrest connecting member 8, a seat connecting member 9, and a footrest connecting member 10; the left and right sides of the base 5 are fixedly connected to the two armrests 3; the actuator 6 is hinged to the base 5 and acts on the transmission connecting rod 7 through a transversely arranged square tube 11, and one end of the actuator 6 equipped with a motor is hinged to the base 5 The end of the telescopic rod of the actuator 6 is rotatably connected to the square tube 11; the transmission connecting rod 7 is rotatably connected to the base 5; the backrest connecting member 8 is inserted in the backrest 1 and fixedly connected by screws, and the backrest connecting member 8 is transmission-connected to the transmission connecting rod 7 through the backrest connecting rod assembly; the footstool connecting member 10 is fixedly connected to the footrest by screws, and the footstool connecting member 10 is transmission-connected to the transmission connecting rod 7 through the footstool connecting rod assembly; the seat connecting member 9 is fixedly connected to the seat 2 by screws, and the seat connecting member 9 is rotatably connected to the seat connecting rod 12.

[0067] like Figure 4-9As shown, a cylindrical lifting member 13 is provided on the transmission connecting rod 7, and the lifting member 13 is located in front of the rotation connection point between the transmission connecting rod 7 and the base 5 and at the rear and lower part of the connection point between the seat connecting member 9 and the seat connecting rod 12; the seat includes four states: assisted standing, normal sitting, extended footrest and lying; these four states are all adjusted and controlled by the actuator 6; when switching from normal sitting to assisted standing, the actuator 6 extends forward and drives the transmission connecting rod 7 to swing forward and upward, the lifting member 13 lifts the seat connecting member 9, the rear part of the seat connecting member 9 swings upward, and drives the seat 2 to swing synchronously; when the seat is in the assisted standing state, the rear part of the seat 2 is suspended.

[0068] In this embodiment, since the base 5 is fixedly connected between the two handrails 3, the base 5 is always fixed, and all the rods rotatably connected to the base 5 can only rotate but cannot move. Due to the limitation formed by the connection between the rods, the rotation angle of the rods rotatably connected to the base 5 cannot reach 360°, which can also be said that the rods rotatably connected to the base 5 can only swing. Since the transmission connecting rod 7 is rotatably connected to the base 5, there are only two directions of movement. Therefore, the transmission connecting rod 7 rotates upward or the transmission connecting rod 7 rotates forward, which means that the transmission connecting rod 7 rotates upward and forward, and the transmission connecting rod 7 rotates backward or the transmission connecting rod 7 rotates downward, which means that the transmission connecting rod 7 rotates downward and backward. The same applies to other rods rotatably connected to the base 5.

[0069] Specifically, if Figure 3 , 4 As shown, the mechanical extension unit 4a also includes a first push-pull rod 14, a lifting link 15, a footstool push-pull rod 16, a first footstool link 17, a second footstool link 18, a third footstool link 19, a fourth footstool link 20, a fifth footstool link 21, a second push-pull rod 22, a first backrest link 23, a second backrest link 24 and a driven link 25.

[0070] like Figure 3 , 6As shown in Figure 10, the left and right ends of the square tube 11 are fixedly connected to the transmission connecting rods 7 on the left and right sides. The transmission connecting rod 7 is a triangular plate-shaped member, including a connecting end 7a connected to the square tube 11, a rotating shaft end 7b rotatably connected to the base 5, and a lifting end 7c provided with a lifting member 13, the lifting end 7c is located at the front side of the rotating shaft end 7b and the connecting end 7a, and the lifting member 13 is installed on the lifting end 7c by screws, and the connecting end 7a is located below the rotating shaft end 7b and the lifting end 7c; a first transmission point 7d and a second transmission point 7e are provided between the rotating shaft end 7b and the lifting end 7c, the first transmission point 7d is rotatably connected to the first push-pull rod 14, the first push-pull rod 14 is used to lift the seat connecting rod 12, and the second push-pull rod 14 is rotatably connected to the second transmission point 7e. The pull rod 22 and the second push-pull rod 22 are used to drive the backrest connecting member 8 to move; when the seat is switched from a normal sitting state to an assisted standing state, the transmission link 7 drives the first push-pull rod 14 and the second push-pull rod 22 to move forward, the first push-pull rod 14 first drives the seat connecting rod 12 to move downward and forward and then drives the seat connecting rod 12 back to its original position, and the second push-pull rod 22 drives the backrest connecting member 8 and the backrest 1 to lean forward; when the seat is switched from a normal sitting state to an extended footrest state or a lying state, the actuator 6 retracts and drives the transmission link 7 to rotate downward and backward, the transmission link 7 drives the first push-pull rod 14 and the second push-pull rod 22 to move backward, the first push-pull rod 14 lifts the seat connecting rod 12 upward and backward, and the second push-pull rod 22 drives the backrest connecting member 8 and the backrest 1 to lean back.

[0071] First, the movement of the seat 2 is described. In the normal sitting state, the leg-resting state, and the lying state, the seat 2 and the seat connector 9 are synchronized with the seat connecting rod 12, and the seat connector 9 and the seat 2 are supported by the seat connecting rod 12; in the auxiliary standing state, such as Figure 8 , 9 As shown in Figures 28, the rear portion of the seat connector 9 is separated from the rear portion of the seat connecting rod 12, with an angle therebetween, and the seat 2 can be tilted forward to an angle of 28° with the horizontal plane; the rotation connection point between the seat connector 9 and the seat connecting rod 12 is located at the front end portion of the seat connector 9 and the front end portion of the seat connecting rod 12. The existing mechanical extension devices 4 with auxiliary standing function are almost all lifted as a whole to achieve this function, which will push the center of gravity of the human body forward and upward, while in the present invention, the rotation point of the seat 2 is close to the human knee joint, which lifts the human hips to rotate the knee joint to assist the user in standing, which is more ergonomic.

[0072] A seat return spring 26 is provided between the seat connecting member 9 and the seat connecting rod 12. The seat return spring 26 is configured to give a force for the rear portion of the seat connecting member 9 to rotate downward. The seat connecting rod 12 is provided with a first spring fixing column 27 below the rotation connection point between the seat connecting member 9 and the seat connecting member 9. The seat connecting member 9 extends downwardly with a connecting ear 28 with a hole at the oblique rear lower part of the rotation connection point between the seat connecting member 9 and the seat connecting rod 12. One end of the seat return spring 26 is arranged on the first spring fixing column 27, and the other end is arranged on the connecting ear 28. The seat connecting rod 12 is located on the outer side of the seat connecting member 9. A supporting plate 29 extends inwardly from the position of the seat connecting member 12 near the rear end. A limiting plate 30 extends outwardly from the seat connecting member 9 at the corresponding position. When the seat is in the auxiliary standing state, the limiting plate 30 is separated from the supporting plate 29. In the normal sitting, stretching the footrest and lying state, the limiting plate 30 is resting on the supporting plate 29 under the action of the seat return spring 26.

[0073] The seat connecting member 9 is fixed with a first seat mounting plate 31 and a second seat mounting plate 32 for mounting the seat 2 by screws. The first seat mounting plate 31 and the second seat mounting plate 32 are both facing the inner side of the mechanical extension device 4, and the first seat mounting plate 31 is located in front of the second seat mounting plate 32. The rear part of the first seat mounting plate 31 is bent downward to form a catering plate 33 for catering to the lifting member 13. The lifting member 13 is located below the catering plate 33 and the lifting member 13 also faces the inner side of the mechanical extension device 4. When the seat is switched from normal sitting to assisted standing, the lifting member 13 pushes up the catering plate 33 and drives the rear part of the seat connecting member 9 to swing upward.

[0074] The rear end of the lifting link 15 is rotatably connected to the base 5, the front end of the lifting link 15 is rotatably connected to the seat link 12, the rear end of the first push-pull rod 14 is rotatably connected to the transmission link 7, and the front end of the first push-pull rod 14 is rotatably connected to the lifting link 15; when the transmission link 7 is driven by the actuator 6 to rotate backward, it drives the first push-pull rod 14 to move backward, the first push-pull rod 14 pulls the lifting link 15 backward, the front end of the lifting link 15 rotates upward and backward, and the seat link 12 is lifted upward and backward; the rear end of the seat link 12 is connected to the rotating upper end of the driven link 25, and the lower end of the driven link 25 is rotatably connected to the base 5. The driven link 25 is configured to support the seat link 12 and keep the seat 2 approximately horizontal. It is because of the existence of the driven link 25 that the seat link 12 can remain approximately horizontal when switching between different states.

[0075] In normal sitting and lying states, the seat 2 has an angle of 8° with the horizontal plane. In the extended footrest state, the seat 2 also tilts backward and the reclining angle with the horizontal plane is 9.5° to improve the sitting comfort. The change of the reclining angle of the seat 2 occurs with the movement of the four-bar linkage where the seat connecting rod 12 is located; in the movement of the seat connecting rod 12, the base 5, the driven connecting rod 25, the seat connecting rod 12 and the lifting connecting rod 15 form a four-bar linkage with a double rocker. In the movement of driving the seat connecting rod 12, the base 5, the transmission connecting rod 7, the first push-pull rod 14 and the lifting connecting rod 15 form a four-bar linkage with a double rocker. The specific configurations such as the lengths of the above two four-bar linkages are not described in detail in this embodiment. The final effect is as follows Figure 11-14 As shown:

[0076] In the process of switching from the normal sitting state to the assisted standing state, the actuator 6 extends forward to make the transmission link 7 rotate forward, and the transmission link 7 drives the first push-pull rod 14 to first push the lifting link 15 forward, so that the lifting link 15 rotates downward and drives the seat link 12 to move forward and downward, and then pulls the lifting link 15 backward and upward, so that the lifting link 15 rotates upward and drives the seat link 12 back to its original position; when switching from the assisted standing state back to the normal sitting state, the movement process of each link is the same as the above process The process is opposite; when switching from the normal sitting state to the extended footrest state, the actuator 6 retracts backwards to cause the transmission link 7 to rotate backwards, and the transmission link 7 drives the first push-pull rod 14 to move downward and backward, and the first push-pull rod 14 pulls the lifting link 15 to rotate it backward, and the seat link 12 is lifted by the lifting link 15 and accompanied by backward tilt, but when the actuator 6 retracts backwards to switch the extended footrest state to the lying state, the seat link 12 is lifted to the highest point and the backward tilt angle of the seat 2 with the horizontal plane returns to 8°.

[0077] The movement of the footrest is described as follows: Figure 15-17As shown, the footstool link assembly includes a first footstool link 17, a second footstool link 18, a third footstool link 19, a fourth footstool link 20 and a fifth footstool link 21. The upper ends of the first footstool link 17 and the second footstool link 18 are both rotatably connected to the seat link 12, and the rotation connection point between the first footstool link 17 and the seat link 12 is located below the rotation connection point between the second footstool link 18 and the seat link 12. The lower end of the third footstool link 19 is rotatably connected to the first footstool link 17, and the third footstool link 19 is rotatably connected to the second footstool link 18 above the rotation connection point between the third footstool link 19 and the first footstool link 17. The lower end of the second footstool link 18 is rotatably connected to the lower end of the fourth footstool link 20, and the front end of the fifth footstool link 21 is rotatably connected to the first footstool link 17. The end is rotatably connected to the rear end of the footstool connecting member 10, the upper end of the third footstool connecting rod 19 is rotatably connected to the rear end of the fifth footstool connecting rod 21, and the upper end of the fourth footstool connecting rod 20 is rotatably connected to the middle part of the fifth footstool connecting rod 21; a second spring fixing column 34 is provided on the fifth footstool connecting rod 21 and the second spring fixing column 34 is located below the footstool connecting member 10, a third spring fixing column 35 is provided in the middle part of the footstool connecting member 10, and a footrest return spring 36 is provided between the second spring fixing column 34 and the third spring fixing column 35; the two ends of the footstool push-pull rod 16 are rotatably connected to the front end of the base 5 and the first footstool connecting rod 17 respectively; the extension and retraction of the footrest are mainly driven by the seat connecting rod 12, but it must be realized with the driven cooperation of the footstool push-pull rod 16.

[0078] The footrest connecting rod assembly and the footrest connecting member 10 as a whole always move with the movement of the seat connecting rod 12. When switching from the normal sitting state to the auxiliary standing state, the seat connecting rod 12 and the footrest connecting rod assembly first move forward and downward, and the moving distance is short, and the footrest push-pull rod 16 has little effect on the footrest connecting rod assembly. Afterwards, the seat connecting rod 12 and the footrest connecting rod assembly return to their original positions, and the footrest push-pull rod 16 hardly causes the footrest connecting rod assembly to move during the whole process.

[0079] When switching from the normal sitting state to the extended footrest state, the actuator 6 retracts and drives the transmission link 7 to rotate backward, the transmission link 7 drives the first push-pull rod 14 to move backward, the first push-pull rod 14 pulls the lifting link 15 backward, the front end of the lifting link 15 rotates upward and backward, and makes the seat link 12 and the footrest link assembly lift upward and backward, the front end of the footstool push-pull rod 16 rotates upward accordingly and pushes the footstool link assembly to extend forward, the second spring fixing column 34 of the fifth footstool link 21 lifts the footstool connector 10 and makes it flip upward, and the footrest also flips accordingly; when switching from the extended footrest state back to the normal sitting state, the movement process of each link is opposite to the above, and the footrest return spring 36 enables the footstool connector 10 to flip downward and retract with the movement of the fifth footstool link 21; the effect of the footstool push-pull rod 16 on the footstool link assembly is passive rather than active.

[0080] In this movement process, it is also realized through a set of connecting rod mechanisms, such as Fig.18 , 19 As shown, the connecting rod mechanism includes a fixed base 5, a seat connecting rod 12 that can only move in translation, a lifting connecting rod 15 that can only rotate, a footstool push-pull rod 16 that can only rotate, and a first footstool connecting rod 17 that can move in translation and rotate. The mechanism of the above five connecting rods makes the movement of the entire mechanism certain because the seat connecting rod 12 can only move in translation. When the lifting connecting rod 15 drives the seat connecting rod 12 to move in translation backward, under the limiting action of the footstool push-pull rod 16, the first footstool connecting rod 17 moves in translation with the seat connecting rod 12 while its lower end rotates forward, thereby extending and opening the entire footstool connecting rod assembly; the seat connecting rod 12 will tilt in this process of sitting, but the tilt angle is small. The "seat connecting rod that can only move in translation" in the above analysis is theoretical.

[0081] The footrest connecting member 10 is rotatably connected to the fifth footrest connecting rod 21 and is movable relative to the footrest connecting rod assembly. Together with the elasticity of the footrest return spring 36, the footrest portion of the seat has a hand-prevention function.

[0082] Finally, the movement of the backrest 1 is described, such as Figure 20-26 As shown, the backrest connecting rod assembly is a second push-pull rod 22, a first backrest connecting rod 23 and a second backrest connecting rod 24. The front end of the second push-pull rod 22 is rotatably connected to the transmission connecting rod 7, and the rear end of the second push-pull rod 22 is rotatably connected to the first backrest connecting rod 23. The first backrest connecting rod 23 is roughly L-shaped, and its corner is rotatably connected to the base 5. The rear end of the first backrest connecting rod 23 is rotatably connected to the front end of the backrest connecting member 8. The backrest connecting member 8 is also L-shaped, and the corner of the backrest connecting member 8 is rotatably connected to the upper end of the second backrest connecting rod 24. The upper part of the backrest connecting member 8 is inserted in the backrest 1 and fixed by screws. The lower end of the second backrest connecting rod 24 is rotatably connected to the base 5, and the first backrest connecting rod 23 is located in front of the second backrest connecting rod 24.

[0083] In the movement of the backrest connecting member 8, the base 5, the first backrest connecting rod 23, the second backrest connecting rod 24 and the backrest connecting member 8 form a four-bar linkage with double rockers. In the movement of driving the backrest connecting member 8 to move, the base 5, the transmission connecting rod 7, the second push-pull rod 22 and the first backrest connecting rod 23 form a four-bar linkage with double rockers. In the four-bar linkage that drives the backrest connecting member 8 to move, the transmission connecting rod 7 is driven by the actuator 6 to rotate relative to the base 5, and the second push-pull rod 22 is driven by the transmission connecting rod 7 to push the first backrest connecting rod 23 relative to the base. 5 is rotated downward or the first backrest connecting rod 23 is pulled to rotate upward relative to the base 5; during the movement of the backrest connecting member 8, the movement of the first backrest connecting rod 23 causes the backrest connecting member 8 to move, the first backrest connecting rod 23 rotates relative to the base 5 to drive the backrest connecting member 8 to move, and the second backrest connecting rod 24 also rotates relative to the base 5 accordingly. Under the joint action of the first and second backrest connecting rods 24, the backrest connecting member 8 moves forward and tilts backward, and the backrest connecting member 8 moves backward and tilts forward, thereby realizing the backward and forward tilting of the backrest 1.

[0084] like Figure 27-30 As shown, different states of the seat and the seat is driven by a single actuator 6 to switch between different states:

[0085] The stroke of the actuator 6 is 200 mm. When the actuator 6 is retracted to the shortest position, it is the origin of the stroke of the actuator 6 .

[0086] Normal sitting: The stroke of the actuator 6 is 128.5 mm, the seat 2 has a backward tilt angle of 8°, the backrest 1 also tilts backward and has an inclination angle of 100° relative to the horizontal plane, and the footrest is now folded under the seat 2 between the two armrests 3, and the user can maintain a normal sitting posture while sitting on the seat.

[0087] Normal sitting to assisted standing: the actuator 6 extends forward, and its stroke increases. The actuator 6 drives the square tube 11 forward to move. The square tube 11 drives the transmission connecting rods 7 on both sides to swing forward and upward relative to the base 5. The rotation angle is 27.5°. The first push-pull rod 14, the second push-pull rod 22 and the lifting member 13 on the transmission connecting rod 7 move accordingly; the lifting member 13 on the transmission connecting rod 7 moves forward and upward and lifts up the frame of the seat 2, so that the rear of the seat 2 is lifted; at the same time, the second push-pull rod 22 As the transmission link 7 swings, the first backrest link 23 is pulled up, and the rear end of the first backrest link 23 swings backward and downward, cooperating with the third backrest 1 link which can only swing to make the backrest connecting member 8 tilt forward, and the backrest 1 tilts forward accordingly; in addition to the help provided by the seat 2 for assisting standing, the backrest 1 also gives a force to the human back forward; the movement of the seat link 12 and the footstool link assembly caused by the first push-pull rod 14 has been described above, and again, no further description is given, and the footrest is still folded under the seat 2.

[0088] Assisted standing: The stroke of the actuator 6 is 200 mm, the seat 2 has a forward tilt angle of 28°, the backrest 1 is also tilted forward and has an inclination angle of 84° relative to the horizontal plane, and the footrest is still folded under the seat 2 between the two armrests 3. At this time, the seat assists the user to stand, and the user can easily stand up from the seat.

[0089] At this time, if the seat is to be switched to the extended footrest state, it is first necessary to switch from the assisted standing state back to the normal sitting state, and the stroke position of the actuator 6 is retracted from 200mm to 128.5mm; during this process, the lifting member 13 moves rearward and downward, and the seat connecting member 9 is pulled by the seat return spring 26 and rotates against the lifting member 13, and the rear part of the seat connecting member 9 rotates downward until the limit plate 30 rests on the supporting plate 29.

[0090] Normal sitting to extending the footrest: the actuator 6 continues to retract and pulls the transmission link 7 backward. The transmission link 7 swings downward and backward relative to the base 5 at an angle of 18.9°. The first push-pull rod 14 is pulled and drives the front end of the lifting link 15 to rotate upward and backward. The seat link 12 and the seat connecting member 9 rotatably connected and resting thereon are lifted, and the footrest link assembly rotatably connected to the seat link 12 is also lifted. At this time, the footrest push-pull rod 16 rotatably connected to the base 5 swings forward and upward with the movement of the footrest link assembly. The footrest push-pull rod 16 pushes the first footrest link 17 forward, and the lower end of the first footrest link 17 rotates forward to drive the third footrest link 19 to move , since the third footstool link 19 is rotatably connected to the second footstool link 18, the lower end of the second footstool link 18 also swings forward and upward, and the fourth footstool link 20 also moves forward and upward accordingly, and finally the fifth footstool link 21 moves upward and forward, while the front end of the fifth footstool link 21 rotates forward and upward and the second spring fixing column 34 lifts the footstool connector 10, so that the footstool connector 10 is unfolded forward and upward, and the footrest portion is extended out for resting the foot; at the same time, the second push rod moves backward to drive the front end of the first backrest link 23 to rotate downward and backward, and the rear end of the first backrest link 23 swings forward, and cooperates with the second backrest link 24 to make the backrest connector 8 recline slightly, and the backrest 1 reclines slightly accordingly.

[0091] When the footrest is extended to a normal sitting position, the actuator 6 extends forward, and the movement process of each connecting rod is opposite to that described above. The recovery of the footrest connecting member 10 is achieved by the footrest return spring 36, which has been described before.

[0092] Extending the footrest: The stroke of the actuator 6 is 71.9 mm, the seat 2 has a rearward tilt angle of 9.5°, the backrest 1 also tilts backward and has an inclination angle of 115° relative to the horizontal plane. The footrest is now extended to the front of the seat, the user's legs are lifted behind the footrest, and the user can still maintain a sitting position and lean back on the backrest 1.

[0093] Extend the footrest to lie down: the actuator 6 continues to retract, the transmission connecting rod 7 continues to rotate backward 23.9°, the footrest is further extended and lifted, the seat connecting rod 12 is further lifted so that the seat 2 as a whole is also lifted, the backrest 1 moves forward and further reclines, the seat 2 is close to the backrest 1, and the movement of the backrest 1 and the seat 2 makes the relative position of the human body's buttocks and waist remain almost unchanged, there is no relative displacement between the two, and there will be no situation of rubbing the back and moving the waist, so that the user can switch from a sitting position to a lying position more comfortably on the seat.

[0094] Lying down: The stroke position of the actuator 6 is 0 mm, the seat 2 has a rearward tilt angle of 8°, the backrest 1 further tilts backward and has an inclination angle of 145 degrees relative to the horizontal plane, and the lower part of the backrest 1 is in contact with the rear part of the seat 2; the footrest also extends further forward and upward, and the user can lie on the seat with the user's legs supported by the footrest.

[0095] The shape and structure of the connecting rod prevent interference during movement:

[0096] The supporting plate 29 on the seat connecting rod 12 and the limiting plate 30 on the seat connecting member 9 allow the seat connecting rod 12 and the seat connecting member 9 to be overlapped while there is a gap between the two, so that the transmission connecting rod 7 can be accommodated between the seat connecting rod 12 and the seat connecting member 9, and the movements of the three will not interfere with each other; in the width direction, the second push-pull rod 22 and the first backrest connecting rod 23 are also within the gap range between the seat connecting rod 12 and the seat connecting member 9, so the seat 2 will not interfere with the movement of the second push-pull rod 22 and the first backrest connecting rod 23, the rear part of the second push-pull rod 22 is bent downward relative to its front part, and the front and rear parts of the first backrest connecting rod 23 also have an angle, which is also to avoid the seat 2 to avoid interference, so that the seat 2 and the backrest 1 can be close to each other normally, realizing the function of preventing back rubbing and waist running.

[0097] Compared with the existing mechanical extension device 4, the mechanical extension device 4 used in the seat of the present invention has greatly simplified its structure. Only one actuator 6 is needed to switch between the four states of normal sitting, assisted standing, extended footrest and lying. The number of connecting rods is small and the structure is simple, which makes the originally complex movement simple, and the movement process is more fixed and programmed (there are more connecting rods that can only rotate with the base 5); the rod limiters at multiple positions in each state are cancelled, the footrest connector 10 and the seat connector 9 are all lifted by the lifting member 13 and fall back by the spring, and the backrest connector 8 is locked in the position of different states by the actuator 6; therefore, the production and assembly costs are greatly reduced, but the reliability is improved.

Claims

1. A seat, characterized in that include: a backrest configured to support a human back; a seat portion configured to support a buttocks of a human body; The footrest is configured to be folded under the seat when the footrest is retracted, and to support the legs of the human body when the footrest is extended; two armrests located on the left and right sides of the backrest and the seat, the armrests being configured to support human arms; A mechanical extension device is suspended between two armrests; the mechanical extension device comprises a base, a mechanical extension unit mirror-imaged on both sides of the base, and an actuator for driving the mechanical extension unit, wherein the mechanical extension unit comprises a transmission connecting rod, a backrest connecting member, a seat connecting member, and a footrest connecting member; the left and right sides of the base are fixedly connected to the two armrests; the actuator is hinged to the base and acts on the transmission connecting rod; the transmission connecting rod is rotatably connected to the base, and one end of the actuator is rotatably connected to the transmission connecting rod; the backrest connecting member is fixedly connected to the backrest, and the backrest connecting member is transmission-connected to the transmission connecting rod through a backrest connecting rod assembly; the footrest connecting member is fixedly connected to the footrest, and the footrest connecting member is transmission-connected to the transmission connecting rod through a footrest connecting rod assembly; the seat connecting member is fixedly connected to the seat, and the seat connecting member is rotationally connected to the seat connecting rod; A cylindrical lifting member is provided on the transmission connecting rod, and the lifting member is located at the front side of the rotation connection point between the transmission connecting rod and the base and at the rear and lower side of the connection point between the seat connecting member and the seat connecting rod; a first seat mounting plate and a second seat mounting plate for mounting the seat are provided on the seat connecting member, and the first seat mounting plate is located at the front side of the second seat mounting plate, and the rear part of the first seat mounting plate is bent downward to form a meeting plate for meeting the lifting member, and the lifting member is located below the meeting plate; The seat includes four states: assisted standing, normal sitting, extended footrest and lying; the four states are all adjusted and controlled by the actuator; When switching from normal sitting to assisted standing, the actuator extends forward and drives the transmission connecting rod to swing forward and upward, the lifting part lifts the seat connecting part, the rear part of the seat connecting part swings upward, and drives the seat to swing synchronously, and at the same time the lifting part lifts the engaging plate upward and drives the rear part of the seat connecting part to swing upward; when the seat is in the assisted standing state, the rear part of the seat is left empty.

2. The seat according to claim 1, characterized in that: The pivot point of the seat is located at the front end of the seat.

3. The seat according to claim 2, characterized in that: When the seat is in the assisted standing state, the seat is tilted forward to form an angle of 28° with the horizontal plane.

4. The seat according to claim 1, characterized in that: A seat return spring is provided between the seat connector and the seat connecting rod, and the seat return spring is configured to impart a force for the rear portion of the seat connector to rotate downward.

5. The seat according to claim 4, characterized in that: A supporting plate is provided on the seat connecting rod, and a limiting plate is correspondingly provided on the seat connecting part. When the seat is in the auxiliary standing state, the limiting plate is separated from the supporting plate. In the normal sitting, stretching footrest and lying state, the limiting plate is resting on the supporting plate under the action of the seat return spring.

6. The seat according to claim 1, characterized in that: A transversely arranged square tube is provided between the transmission connecting rods on the left and right sides, the square tube is fixedly connected to the transmission connecting rods on the left and right sides and is rotatably connected to the actuator; the transmission connecting rod is a plate-shaped member, including a connecting end connected to the square tube, a rotating shaft end rotatably connected to the base, and a lifting end provided with a lifting member, the lifting end is located in front of the rotating shaft end and the connecting end, and the connecting end is located below the rotating shaft end and the lifting end; a first transmission point and a second transmission point are provided between the rotating shaft end and the lifting end, a first push-pull rod for lifting the seat connecting rod is rotatably connected at the first transmission point, and a push-pull rod for driving the backrest connecting rod is rotatably connected at the second transmission point When the seat is switched from a normal sitting state to an assisted standing state, the transmission connecting rod drives the first and second push-pull rods to move forward, the first push-pull rod first drives the seat connecting rod to move downward and forward, and then drives the seat connecting rod back to its original position, and the second push-pull rod drives the backrest connecting member and the backrest to tilt forward; when the seat is switched from a normal sitting state to an extended footrest state or a lying state, the actuator retracts and drives the transmission connecting rod to rotate downward and backward, the transmission connecting rod drives the first and second push-pull rods to move backward, the first push-pull rod lifts the seat connecting rod upward and backward, and the second push-pull rod drives the backrest connecting member and the backrest to lean back.

7. The seat according to claim 1, characterized in that: A lifting link is also rotatably provided on the base, the rear end of the lifting link is rotatably connected to the base, and the front end of the lifting link is rotatably connected to the seat link; a first push-pull rod is rotatably provided on the transmission link, and the front end of the first push-pull rod is rotatably connected to the lifting link; when the transmission link is driven by the actuator to rotate backward, it drives the first push-pull rod to move backward, the first push-pull rod pulls the lifting link backward, the front end of the lifting link rotates upward and backward, and the seat link is lifted upward and backward.

8. The seat according to claim 7, characterized in that: The rear end of the seat connecting rod is rotatably connected with a driven connecting rod, which is rotatably connected to the base. The driven connecting rod is configured to support the seat connecting rod and keep the seat horizontal.

9. The seat according to claim 7, characterized in that: The backrest connecting rod assembly includes a second push-pull rod, a first backrest connecting rod and a second backrest connecting rod. The first and second backrest connecting rods are both rotatably connected to the base and the first backrest connecting rod is located in front of the second backrest connecting rod; the front end of the second push-pull rod is rotatably connected to the transmission connecting rod, and the rear end of the second push-pull rod is rotatably connected to the first backrest connecting rod; the upper ends of the first backrest connecting rod and the second backrest connecting rod are both rotatably connected to the backrest connecting member; when the actuator retracts and drives the transmission connecting rod to rotate backward, the seat connecting rod is lifted upward and backward, and the seat is lifted upward and backward accordingly, the second push-pull rod moves backward and drives the upper end of the first backrest connecting rod to rotate forward, so that the backrest connecting member drives the second backrest connecting rod to rotate forward and downward, and the backrest moves forward while tilting backward, and the lower part of the backrest and the rear part of the seat are close to each other.

10. The seat according to claim 9, characterized in that: The footstool connecting rod assembly is rotatably connected to the front end of the seat connecting rod, and a footstool push-pull rod is also provided between the footstool connecting rod assembly and the base, the rear end of the footstool push-pull rod is rotatably connected to the base, and the front end of the footstool push-pull rod is rotatably connected to the footstool connecting rod assembly; when the seat is switched from the auxiliary standing state to the extended footrest state, the actuator retracts, so that the seat first returns to the normal sitting state from the auxiliary standing state, and the actuator continues to retract to drive the transmission connecting rod to rotate backward, and the transmission connecting rod drives the first and second push-pull rods to move backward, the first push-pull rod pulls the lifting connecting rod backward, and the front end of the lifting connecting rod rotates upward and backward, and the seat connecting rod and the footstool connecting rod assembly are lifted upward and backward, and the front end of the footstool push-pull rod rotates upward accordingly and pushes the footstool connecting rod assembly to extend the footstool connecting rod assembly forward, and the footstool connecting member and the footrest are also extended accordingly; the second push-pull rod causes the backrest connecting member and the backrest to move forward while tilting backward.

11. The seat according to claim 10, characterized in that: When the seat switches from the extended footrest state to the lying state, the actuator continues to retract to the shortest state, the footrest is in a fully extended state, the lower end of the backrest is in contact with the rear end of the seat and the backrest is reclined to 145°.

12. The seat according to claim 1, characterized in that: The actuator is an electric push rod.

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