Electric extension device for sofa

Abstract

The present invention is applicable to the technical field of sofas, and provides an electric extension device for a sofa, comprising: a base mechanism; a seat mechanism, rotatably connected to the base mechanism; a leg support mechanism, two groups of which are arranged oppositely and rotatably connected to both sides of the seat mechanism, and the two groups of leg support mechanisms are connected by a leg driving connecting rod; a backrest mechanism, two groups of which are arranged oppositely and fixedly installed on both sides of the seat mechanism; a first electric push rod, used to drive the seat mechanism to rotate; a second electric push rod, used to drive the leg support structure to unfold and fold; wherein, through the synergistic effect of the first electric push rod and the second electric push rod, the electric extension device for the sofa is in different states to meet different user needs. The electric extension device provided by the present invention has a simple and compact structure, is easy to install, and has flexible, smooth and diversified adjustments, which enhances the user's experience and comfort.

Description

Technical Field

[0001] The invention belongs to the technical field of sofas, and in particular relates to an electric extending device for a sofa. Background Art

[0002] A sofa is a cushioned chair. In people's daily life, sofas have become a very common piece of furniture. Compared with the old wooden seats, the existing cloth or leather sofas can provide people with more comfort. With the continuous improvement of people's living standards, people's requirements for furniture are getting higher and higher. Ordinary sofas with single functions will gradually be abandoned by people. Some sofas are equipped with mechanical extension devices, which are electric and manual. The emergence of these mechanical extension devices enriches the functions of sofas and increases people's experience.

[0003] Existing sofas generally have the functions of tilting and resetting the backrest, and unfolding and folding the legrests. In order to make the adjustment performance of the backrest and legrest in the sofa more flexible, the backrest and legrest in the sofa can be controlled separately to adapt to the different resting postures of the users. At present, there are two common shortcomings in the mechanical extension devices of existing sofas: 1. The design is complex, there are too many steps, and the limiting method is complicated, which makes the overall structure of the mechanical extension device too complicated, reduces the smoothness of the iron frame during operation, and the possibility of problems with the iron frame during operation is very high; 2. There is no safety anti-pinch device, the appearance and structure are bulky, and the safety and reliability of the mechanical extension device are reduced. Therefore, there is still room for improvement in the extension device of the existing sofa to solve the above problems, so that the folding and unfolding of the sofa can be smoother, and the adjustment performance can be more flexible, so as to obtain a larger consumer market for manufacturers. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide an electric sofa extension device, aiming to solve the problems of the existing sofa extension device having a complex structure, poor adjustment performance, and low safety.

[0005] The embodiment of the present invention is implemented as follows: an electric sofa extension device, the electric sofa extension device comprising:

[0006] Base mechanism;

[0007] A seat mechanism, rotatably connected to the base mechanism;

[0008] The leg support mechanism is provided in two groups opposite to each other and is rotatably connected to the two sides of the seat mechanism, and the two groups of leg support mechanisms are connected by a leg driving connecting rod;

[0009] The backrest mechanism is provided in two sets opposite to each other and fixedly mounted on both sides of the seat mechanism;

[0010] A first electric push rod, the rear end of which is hinged to the base mechanism, and the front end of which is hinged to the seat mechanism, for driving the seat mechanism to rotate;

[0011] The second electric push rod has a rear end hinged to the seat mechanism and a front end hinged to the leg driving connecting rod, and is used to drive the leg support structure to unfold and fold;

[0012] Among them, the seat mechanism includes an upper frame side panel and a backrest connecting piece, the backrest connecting piece is fixedly connected to the upper frame side panel, and is hinged to the front end of the first electric push rod and to the rear end of the second electric push rod; the upper frame side panel is rotatably connected to the base mechanism; the first electric push rod pushes the backrest connecting piece to move, driving the upper frame side panel to rotate around the rotation connection point between the upper frame side panel and the base mechanism to adjust the angle of the backrest mechanism and the seat mechanism, and the second electric push rod drives the leg support mechanism to unfold and fold, so that the sofa electric extension device is in different states to meet different needs of users.

[0013] An electric extension device for a sofa provided in an embodiment of the present invention adjusts the inclination angle of the backrest mechanism through the first electric push rod, and drives the leg support structure to unfold and fold through the second electric push rod, so that the entire electric extension device is in a variety of different states to meet the needs of different users. The electric extension device has a simple and compact structure, is easy to install, and has flexible, smooth and diversified adjustment, which can meet the different needs of users and enhance the user's experience and comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A three-dimensional structural diagram of an electric sofa extension device provided by an embodiment of the present invention;

[0015] Figure 2 A front view of a sofa electric extension device in TV state provided by an embodiment of the present invention;

[0016] Figure 3 A front view of a sofa electric extension device provided by an embodiment of the present invention in a sitting position;

[0017] Figure 4 A front view of a sofa electric extension device in a zero gravity state provided by an embodiment of the present invention;

[0018] Figure 5 A schematic diagram of the structure of a leg driving connecting rod of a sofa electric extension device provided by an embodiment of the present invention;

[0019] Figure 6 It is a structural schematic diagram of a backrest connecting member of a sofa electric extension device provided in an embodiment of the present invention;

[0020] Figure 7A structural diagram of a base mechanism of an electric extension device for a sofa provided in an embodiment of the present invention;

[0021] Figure 8 A schematic structural diagram of a hand pinching prevention device for an electric extension device of a sofa provided in an embodiment of the present invention.

[0022] In the attached drawings: 1. large footrest; 2. first connecting rod; 3. second connecting rod; 4. third connecting rod; 5. fourth connecting rod; 6. fifth connecting rod; 7. sixth connecting rod; 8. small footrest; 9. upper shelf side plate; 10. seat frame mounting member; 10a. seat frame mounting member; 11. base side plate 1; 12. first electric push rod rear connecting member; 13. first electric push rod front connecting member; 14. base mounting plate 1; 15. rotating screw; 16. backrest member; 17. backrest mounting member; 18. limit member; 19. L-shaped mounting member; 19a. L-shaped mounting member; 19b. L-shaped mounting member; 19c, L-shaped mounting piece; 20, front connecting piece of the second electric push rod; 21, rear connecting piece of the second electric push rod; 22, leg driving connecting rod; 23, base connecting pipe 1; 23a, base connecting pipe 2; 24, backrest connecting pipe; 25, first electric push rod; 26, second electric push rod; 39, base mounting piece 2; 40, base side plate 2; 42, upper side plate connecting pipe; 43, nut; 44, base mounting piece 2 threaded hole; 45, base mounting piece 1 threaded hole; 50, first electric push rod front connecting piece mounting hole; 51, second electric push rod front connecting piece mounting hole. 52, first limit surface; 53, limit pin; 54, second limit surface. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0025] like Figure 1-4 FIG. 1 is a structural diagram of an electric sofa extension device provided by an embodiment of the present invention, wherein the electric sofa extension device comprises:

[0026] Base mechanism;

[0027] A seat mechanism, rotatably connected to the base mechanism;

[0028] The leg support mechanism is provided in two groups opposite to each other and is rotatably connected to the two sides of the seat mechanism, and the two groups of leg support mechanisms are connected by a leg driving connecting rod;

[0029] The backrest mechanism is provided in two sets opposite to each other and fixedly mounted on both sides of the seat mechanism;

[0030] A first electric push rod 25, the rear end of which is hinged to the base mechanism, and the front end of which is hinged to the seat mechanism, for driving the seat mechanism to rotate;

[0031] A second electric push rod 26, the rear end of which is hinged to the seat mechanism, and the front end of which is hinged to the leg driving connecting rod 22, is used to drive the leg support structure to unfold and fold;

[0032] Among them, the seat mechanism includes an upper frame side panel and a backrest connecting piece, the backrest connecting piece is fixedly connected to the upper frame side panel, and is hinged to the front end of the first electric push rod 25 and the rear end of the second electric push rod 26; the upper frame side panel is rotatably connected to the base mechanism; the first electric push rod 25 pushes the backrest connecting piece to move, driving the upper frame side panel to rotate around the rotation connection point between the upper frame side panel and the base mechanism to adjust the angle of the backrest mechanism and the seat mechanism, and the second electric push rod 26 drives the leg support mechanism to unfold and fold, so that the sofa electric extension device is in different states to meet different user needs.

[0033] In the embodiment of the present invention, the first electric push rod 25 is used to adjust the inclination angle of the backrest mechanism, and the second electric push rod 26 is used to drive the leg support structure to unfold and fold, so that the entire electric extension device is in a variety of different states to meet the needs of different users. The electric extension device has a simple and compact structure, is easy to install, and has flexible, smooth and diversified adjustment. The electric extension device can be in a variety of different states to meet the different needs of users, thereby enhancing the user's experience and comfort.

[0034] In one embodiment of the present invention, the first electric push rod 25 and the second electric push rod 26 are both a combination of a drive motor and a piston rod; the drive motor drives the piston rod to perform telescopic movement.

[0035] In one embodiment of the present invention, the upper frame side plate includes an upper frame side plate 9 and an upper frame side plate 35, and the upper frame side plate 9 and the upper frame side plate 35 are respectively rotatably connected to the left and right sides of the base mechanism; Figure 6 As shown, the backrest connecting member includes a front connecting member 13 of the first electric push rod, a rear connecting member 21 of the second electric push rod, a backrest connecting tube 24 and an upper frame side panel connecting tube 42; an L-shaped mounting member 19b is fixedly installed on the upper frame side panel 1 9, and an L-shaped mounting member 19c is fixedly installed on the upper frame side panel 2 35; the L-shaped mounting member 19b and the L-shaped mounting member 19c are fixedly connected to the upper frame side panel connecting tube 42, thereby fixing the backrest connecting member between the upper frame side panel 1 9 and the upper frame side panel 2 35.

[0036] In one embodiment of the present invention, the backrest mechanism is provided with two groups fixedly installed on the left and right sides of the seat mechanism, and the backrest mechanism includes a backrest member 16 and a backrest mounting member 17; one end of the backrest member 16 of the left backrest mechanism is fixedly connected to the upper frame side panel 9, and the other end is fixedly connected to one end of the backrest mounting member 17; the other end of the backrest mounting member 17 is fixedly connected to the left side of the backrest connecting tube 24 on the backrest connecting member; similarly, one end of the backrest member 16 of the right backrest mechanism is fixedly connected to the upper frame side panel 35, and the other end is fixedly connected to one end of the backrest mounting member 17; the other end of the backrest mounting member 17 is fixedly connected to the right side of the backrest connecting tube 24 on the backrest connecting member.

[0037] like Figure 7 As shown, in one embodiment of the present invention, the base mechanism includes a base side panel 11, a base side panel 2 40, a base connecting pipe 1 23 and a base connecting pipe 2 23a; the base side panel 11 and the base side panel 2 40 have exactly the same shape and structure, the base side panel 11 and the base side panel 2 40 are placed opposite and parallel to each other, and the base side panel 11 and the base side panel 2 40 are fixedly connected together through the base connecting pipe 1 23 and the base connecting pipe 2 23a; a first electric push rod rear connecting piece 12 is fixedly connected to the base connecting pipe 2 23a, and a first electric push rod front connecting piece mounting hole 50 is provided on the first electric push rod rear connecting piece 12; the first electric push rod 25 is hinged to the base mechanism through the first electric push rod front connecting piece mounting hole 50 on the first electric push rod rear connecting piece 12.

[0038] In one embodiment of the present invention, the base side panel 11 is provided with a base mounting piece 14, and the base side panel 2 40 is provided with a base mounting piece 39 at a corresponding position; the base mounting piece 14 is provided with a threaded hole 45, and the base mounting piece 39 is provided with a threaded hole 44; the upper frame side panel 19 and the upper frame side panel 2 35 are provided with threaded holes at corresponding mounting positions; the base side panel 11 and the upper frame side panel 9 are rotatably connected by rotating screws 15 through the threaded holes 45 on the base mounting piece 14 and the threaded holes on the upper frame side panel 9 and fastened by nuts 43; similarly, the base is rotatably connected by rotating screws 15 through the threaded holes 45 on the base mounting piece 14 and the threaded holes on the upper frame side panel 9 The threaded hole 44 of the mounting plate 39 and the threaded hole on the upper frame side plate 35 rotatably connect the base side plate 40 and the upper frame side plate 35 and fasten them by the nut 43; when the first electric push rod 25 is retracted, it will pull the backrest connecting piece to move forward, drive the upper frame side plate to rotate clockwise around the rotation connection point between it and the base side plate, and then drive the backrest mechanism to tilt backward; conversely, when the first electric push rod 25 is opened, it will pull the backrest connecting piece to move backward, drive the upper frame side plate to rotate counterclockwise around the rotation connection point between it and the base side plate, and then drive the backrest mechanism to tilt forward and reset.

[0039] In one embodiment of the present invention, a limit member 18 is provided on the upper frame side panel 1 9 and the upper frame side panel 2 35. The limit member 18 is made of rubber material and is fastened to the bottom of the upper frame side panel 1 9 and the upper frame side panel 2 35 by bonding. When the first electric push rod 25 is fully opened, the limit member 18 contacts and limits the base connecting tube 23. Because the limit member 18 is made of rubber material, it has a certain buffering effect, which can effectively prevent the limit member 18 from being too impacted when contacting the seat connecting tube 23 and damaging the device.

[0040] In one embodiment of the present invention, the leg support mechanism is arranged in two opposite groups and is rotatably connected to the left and right sides of the base mechanism, that is, the left leg support mechanism is rotatably connected to the upper frame side panel 9, and the right leg support mechanism is rotatably connected to the upper frame side panel 2 35; the leg support mechanism includes a large footrest assembly and a connecting rod assembly; the large footrest assembly is rotatably connected to the front end of the connecting rod assembly.

[0041] In one embodiment of the present invention, the connecting rod group includes a first connecting rod 2, a second connecting rod 3, a third connecting rod 4, a fourth connecting rod 5 and a fifth connecting rod 6; the fifth connecting rod 6 is rotationally connected to the large footrest assembly; one end of the first connecting rod 2 is rotationally connected to the first connection point of the fifth connecting rod 6, and the other end of the first connecting rod 2 is rotationally connected to one end of the third connecting rod 4; one end of the second connecting rod 3 is rotationally connected to the second connection point of the fifth connecting rod 6, and the other end of the second connecting rod 3 is connected to one end of the fourth connecting rod 5; the other end of the third connecting rod 4 is rotationally connected to the third connection point of the upper frame side panel, and the other end of the fourth connecting rod 5 is rotationally connected to the fourth connection point of the upper frame side panel; wherein, the first connection point and the second connection point, the third connection point and the fourth connection point The points are non-coaxially arranged, the fourth connecting rod 5 and the third connecting rod 4 are cross-arranged, and the fourth connecting rod 5 and / or the third connecting rod 4 are provided with lateral displacement, so as to form an automatic limit mode and avoid cross-obstruction; the other end of the fourth connecting rod 5 of the left leg support mechanism and the other end of the third connecting rod 4 are rotatably connected to the upper frame side plate 9, and the other end of the fourth connecting rod 5 of the right leg support mechanism and the other end of the third connecting rod 4 are rotatably connected to the upper frame side plate 2 35; an L-shaped mounting piece 19 is installed on the third connecting rod 4 of the left leg support mechanism, and an L-shaped mounting piece 19a is installed on the third connecting rod 4 of the right leg support mechanism, and the leg driving connecting rod 22 is fixedly connected to the third connecting rod 4 on the left and right leg support mechanisms on both sides through the L-shaped mounting piece 19 and the L-shaped mounting piece 19a; Figure 5As shown, the leg driving link 22 is provided with a second electric push rod front connecting piece 20, and the second electric push rod front connecting piece 20 is provided with a second electric push rod front connecting piece mounting hole 51; the second electric push rod 26 is hinged to the leg driving link 22 through the second electric push rod front connecting piece mounting hole 51 on the second electric push rod front connecting piece 20; when the second electric push rod 26 extends and pushes the third connecting rod 4 to rotate, the third connecting rod 4 rotates relative to the fourth connecting rod 5, so that the second connecting rod 3 and the first connecting rod 2 are relatively displaced to form an expansion mode, and when the second electric push rod 26 pulls the third connecting rod 4 to rotate in the opposite direction, the second connecting rod 3 and the first connecting rod 2 are relatively displaced in the opposite direction to form a contraction mode.

[0042] In one embodiment of the present invention, the leg support mechanism also includes a small footrest 8; the small footrest 8 is rotatably connected to the inner side of the second connecting rod 3, and when the leg support mechanism is in a folded state, the small footrest 8 is hidden inside the leg support structure, and when the leg support mechanism is in an open state, the small footrest is rotated to prop up the calf area, thereby preventing leg soreness and making people feel more comfortable.

[0043] In one embodiment of the present invention, Figure 8 As shown, the connecting rod group is provided with an anti-pinch device, namely a large footrest assembly, including a large footrest 1 and a sixth connecting rod 7; the sixth connecting rod 7 is rotatably connected to the large footrest 1, and the angle is adjusted by manually rotating the large footrest 1 to avoid the first connecting rod 2 and the second connecting rod 3 from moving relative to each other and driving the large footrest to rotate and cause pinching.

[0044] In one embodiment of the present invention, a limit pin 53 is provided on the third connecting rod 4, and a second limit surface 54 is correspondingly provided on the second connecting rod 3. When the leg support mechanism is opened, the limit pin 53 contacts the second limit surface 54, so that the rotation range of the second connecting rod 3 is limited.

[0045] In the above embodiment of the present invention, there is provided an electric extension device for a sofa, wherein the first electric push rod 25 pushes the backrest connecting member to move, driving the upper frame side panel to rotate around the rotation connection point between the upper frame side panel and the base mechanism to adjust the angles of the backrest mechanism and the seat mechanism, and the second electric push rod 26 drives the leg support mechanism to be unfolded and folded, that is, by adjusting the first electric push rod 25 and the second electric push rod 26 to open and close, the electric extension device for the sofa is in different states; when the first electric push rod 25 is opened and the second electric push rod 26 is closed, the seat mechanism and the base mechanism are in a folded state, and the leg support mechanism is also in a folded state. At this time, the electric extension device for the sofa is in a sitting state, such as Figure 3Based on the sitting state, the second electric push rod 26 is opened, the leg support mechanism is unfolded, and the electric extension device of the sofa is in the TV state at this time, as shown in FIG. Figure 2 As shown, the TV state refers to a suitable state for watching TV; based on the TV state, the first electric push rod 25 is retracted, and the seat mechanism and the base mechanism are in an extended state, that is, the seat mechanism is tilted upward relative to the base mechanism, the backrest mechanism is tilted backward, and the leg support mechanism is also tilted upward. At this time, lying on the sofa, the human body's knees are slightly higher than the position of the heart, which makes people in a state of no gravity and complete relaxation. At this time, the sofa electric extension device is in a zero-gravity state. Figure 4 As shown; the first electric push rod 25 and the second electric push rod 26 are independently controlled, connected in parallel, and connected with a power plug and a control handle, the power plug is connected to an external socket power supply, after the power is turned on, the sofa electric extension device is flexibly switched between three states through the control handle to meet the different needs of users. The sofa electric extension device provided by the present invention has a simple and compact structure, is easy to install, has flexible and smooth adjustment, is diversified, and is equipped with a hand-pinch prevention device, which improves the comfort and safety of the functional sofa.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electric sofa extension device, characterized in that: The electric sofa extension device comprises: Base mechanism; A seat mechanism, rotatably connected to the base mechanism; The leg support mechanism is provided in two groups opposite to each other and is rotatably connected to the two sides of the seat mechanism, and the two groups of leg support mechanisms are connected by a leg driving connecting rod; The backrest mechanism is provided in two sets opposite to each other and fixedly mounted on both sides of the seat mechanism; A first electric push rod, the rear end of which is hinged to the base mechanism, and the front end of which is hinged to the seat mechanism, for driving the seat mechanism to rotate; The second electric push rod has a rear end hinged to the seat mechanism and a front end hinged to the leg driving connecting rod, and is used to drive the leg support structure to unfold and fold; The seat mechanism comprises an upper frame side panel and a backrest connecting member, wherein the backrest connecting member is fixedly connected to the upper frame side panel, and is hinged to the front end of the first electric push rod and to the rear end of the second electric push rod; the upper frame side panel is rotatably connected to the base mechanism; the first electric push rod pushes the backrest connecting member to move, driving the upper frame side panel to rotate around the rotation connection point between the upper frame side panel and the base mechanism to adjust the angle of the backrest mechanism and the seat mechanism, and the second electric push rod drives the leg support mechanism to unfold and fold, so that the sofa electric extension device is in different states to meet different needs of users. When the first electric push rod is opened and the second electric push rod is folded, the seat mechanism and the base mechanism are in a folded state, and the leg support mechanism is also in a folded state, and the sofa electric extension device is in a sitting state; When the first electric push rod is opened and the second electric push rod is opened, the seat mechanism and the base mechanism are in a folded state, and the leg support mechanism is in an unfolded state, and the sofa electric extension device is in a TV state; When the first electric push rod is folded and the second electric push rod is opened, the seat mechanism and the base mechanism are in an unfolded state, and the leg support mechanism is also in an unfolded state. At this time, the sofa electric extension device is in a zero-gravity state. The upper frame side panel includes an upper frame side panel 1 and an upper frame side panel 2, and the upper frame side panel 1 and the upper frame side panel 2 are respectively rotatably connected to the left and right sides of the base mechanism; the backrest connecting member includes a front connecting member of the first electric push rod, a rear connecting member of the second electric push rod, a backrest connecting pipe and an upper frame side panel connecting pipe; an L-shaped mounting member 19b is fixedly installed on the upper frame side panel 1, and an L-shaped mounting member 19c is fixedly installed on the upper frame side panel 2; the L-shaped mounting member 19b and the L-shaped mounting member 19c are connected to the upper frame side panel 1 The frame side panel connecting tube is fixedly connected, so that the backrest connecting piece is fixedly connected between the upper frame side panel one and the upper frame side panel two, and the backrest mechanism is provided with two groups fixedly installed on the left and right sides of the seat mechanism, and the backrest mechanism comprises a backrest member and a backrest mounting member; one end of the backrest member of the left backrest mechanism is fixedly connected to the upper frame side panel one, and the other end is fixedly connected to one end of the backrest mounting member; the other end of the backrest mounting member is fixedly connected to the left side of the backrest connecting tube on the backrest connecting member; similarly, one end of the backrest member of the right backrest mechanism is fixedly connected to the upper frame side panel two, and the other end is fixedly connected to one end of the backrest mounting member; the other end of the backrest mounting member is fixedly connected to the right side of the backrest connecting tube on the backrest connecting member.

2. The electric sofa extension device according to claim 1, characterized in that: The base mechanism comprises a base side plate and at least one base connecting pipe, and the base connecting pipe is fixedly connected to the base side plate.

3. The electric sofa extension device according to claim 2, characterized in that: The base side plate is provided with a base mounting piece, and the upper frame side plate is rotatably connected to the base mounting piece.

4. The electric sofa extension device according to claim 1, characterized in that: A limiting piece is provided on the upper frame side plate, and when the first electric push rod is fully opened, the limiting piece contacts and limits the base connecting pipe.

5. The electric sofa extension device according to claim 1, characterized in that: The leg support mechanism comprises a large footrest assembly and a connecting rod group; the large footrest assembly is rotatably connected to the front end of the connecting rod group.

6. The electric sofa extension device according to claim 5, characterized in that: The connecting rod group includes a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod and a fifth connecting rod; the fifth connecting rod is rotatably connected to the large footrest assembly; one end of the first connecting rod is rotatably connected to the first connecting point of the fifth connecting rod, and the other end of the first connecting rod is rotatably connected to one end of the third connecting rod; one end of the second connecting rod is rotatably connected to the second connecting point of the fifth connecting rod, and the other end of the second connecting rod is connected to one end of the fourth connecting rod; the other end of the third connecting rod is rotatably connected to the third connecting point of the upper frame side plate, and the other end of the fourth connecting rod is rotatably connected to the upper frame side plate On the fourth connection point of the frame side plate; wherein the first connection point and the second connection point, the third connection point and the fourth connection point are non-coaxially arranged, the fourth connecting rod and the third connecting rod are cross-arranged, and the fourth connecting rod and / or the third connecting rod are provided with a lateral displacement, so as to form an automatic limit mode and avoid cross obstruction; when the second electric push rod is extended and pushes the third connecting rod to rotate, the third connecting rod rotates relative to the fourth connecting rod, so that the second connecting rod and the first connecting rod are relatively displaced to form an expansion mode, when the second electric push rod pulls the third connecting rod to rotate in the opposite direction, the second connecting rod and the first connecting rod are relatively displaced in the opposite direction to form a contraction mode.

7. The electric sofa extension device according to claim 1 or 6, characterized in that: The leg support mechanism also includes a small footrest; the small footrest is rotatably connected to the inner side of the second connecting rod. When the leg support mechanism is in a folded state, the small footrest is hidden inside the leg support structure. When the leg support mechanism is in an open state, the small footrest is rotated to prop up the small footrest to support the calf area.

8. The electric sofa extension device according to claim 6 or 5, characterized in that: The connecting rod group is provided with an anti-pinch device, namely a large footrest assembly, including a large footrest and a sixth connecting rod; the sixth connecting rod is rotatably connected to the large footrest, and the angle is adjusted by manually rotating the large footrest to avoid the first connecting rod and the second connecting rod from moving relative to each other and driving the large footrest to rotate and cause pinching.

9. The electric sofa extension device according to claim 6, characterized in that: The third connecting rod is provided with a limit pin, and the second connecting rod is correspondingly provided with a second limit surface. When the leg support mechanism is opened, the limit pin contacts the second limit surface, so that the rotation range of the second connecting rod is limited.

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