Mechanical stretching device

Abstract

The utility model discloses a mechanical stretching device, which comprises a fixed plate, a seat frame, a telescopic rod and a telescopic rod, the backrest assembly is pivoted with the rear part of the seat frame and comprises a backrest bracket for attaching a backrest; the leg stretching device is pivoted with the front part of the seat frame; at the sitting position, the included angle between the surface, attached to the backrest, of the backrest support and the fixing plate ranges from 110 degrees to 115 degrees; the range of an included angle between the fixing plate and the seat frame is 5-10 degrees; at the lying position, the included angle between the surface, attached to the backrest, of the backrest bracket and the fixed plate is 145-160 degrees; the included angle between the fixing plate and the seat frame ranges from 20 degrees to 30 degrees, when the sitting posture position is changed to the lying posture position, the rearmost portion of the backrest support does not have the trend of moving backwards, the situation that the seat unit moves backwards when the posture is changed can be avoided, and the wall leaning distance can be reduced; due to the large-angle backward leaning design of the backrest bracket of 145-160 degrees and the proper lifting of the seat frame of 20-30 degrees, more relaxed and comfortable lying experience can be provided.

Description

Technical Field

[0001] The utility model relates to the technical field of sofa iron frames, in particular to a mechanical stretching device. Background Art

[0002] With the acceleration of the modern life rhythm and the continuous improvement of people's living standards, the requirements for the comfort, functionality and space utilization rate of the home environment, especially for furniture such as sofas and seats, are increasing day by day. Traditional fixed sofas and seats are difficult to meet the needs of modern families for multi-scene use, flexible transformation and space saving. Movable seat units have gradually become the focus of market attention because of their ability to freely switch between different postures.

[0003] In the existing design of movable seat units, the mechanical stretching device is a key component to realize the transformation between sitting posture, TV posture (i.e., semi-reclining posture, a posture convenient for entertainment activities such as watching TV) and lying posture. Such devices usually achieve the stable transformation of the seat unit in different postures through complex link mechanisms, driving devices and control systems. Specifically, when the seat changes from the sitting position to the leisure position (such as TV posture), the footrest will extend forward to support the legs, and the angle between the backrest and the seat part basically remains unchanged to maintain the comfort of the upper body. Further, when the seat unit changes from the leisure position to the lying position, the footrest will extend further forward and upward compared with the leisure position, and at the same time the backrest will recline significantly to provide a more relaxing lying experience.

[0004] However, although the existing movable seat units are relatively perfect in function, there are still deficiencies in the actual use process. Especially for products such as iron frame sofas, the distance from the wall is generally large, about 16 cm, which not only occupies valuable indoor space, but also is difficult to achieve the zero-wall effect, affecting the cleanliness and beauty of the overall home environment. In addition, the large distance from the wall may also cause the sofa to shake or be unstable during use, further reducing the user's comfort and making it difficult to meet the pursuit of high-standard quality of life by modern families. Summary of the Utility Model

[0005] In order to overcome at least one of the above-mentioned defects of the prior art, the utility model provides a mechanical stretching device, which can effectively reduce the distance from the wall, achieve the zero-wall effect, and improve the stability and comfort of the overall structure while ensuring that the seat unit can freely switch between different postures.

[0006] The technical solution adopted by the utility model to solve its problems is:

[0007] A mechanical stretching device capable of transforming at least between a sitting position, a TV position and a lying position, comprising: a fixed plate, a seat frame pivotally connected above the fixed plate and capable of moving back and forth; a backrest assembly pivotally connected to the rear part of the seat frame, the backrest assembly including a backrest bracket for attaching a backrest; a leg stretching device pivotally connected to the front part of the seat frame; in the sitting position, the included angle range between the surface of the backrest bracket attaching the backrest and the fixed plate is 110° - 115°; the included angle range between the fixed plate and the seat frame is 5° - 10°; in the lying position, the included angle range between the surface of the backrest bracket attaching the backrest and the fixed plate is 145° - 160°; the included angle range between the fixed plate and the seat frame is 20° - 30°, and when transforming from the sitting position to the lying position, the rearmost part of the backrest bracket does not have a tendency to move backward.

[0008] By adopting the above scheme, since the rearmost part of the backrest bracket does not have a tendency to move backward, it can avoid the seat unit from moving backward excessively when changing postures, thus helping to reduce the distance from the wall; at the same time, the large-angle reclining design of the backrest bracket at 145° - 160° and the appropriate lifting of the seat frame at 20° - 30° help to provide a more relaxing and comfortable lying experience.

[0009] Further, the backrest assembly further includes: a first backrest link, one end of the first backrest link is pivotally connected to the front end of the backrest bracket, and the other end is pivotally connected to the seat frame; a second backrest link, one end of the second backrest link is pivotally connected to the rear end of the backrest bracket, and the second backrest link is also pivotally connected to the seat frame.

[0010] By adopting the above scheme, the introduction of the first backrest link and the second backrest link provides additional support and stability for the backrest assembly. When the seat unit transforms from the sitting position to the lying position, it can ensure the smooth movement and rotation of the backrest bracket.

[0011] Further, a seat frame rear extension rod is also assembled between the seat frame and the backrest assembly, the seat frame rear extension rod is fixedly connected to the seat frame, the other end of the first backrest link is pivotally connected to the seat frame rear extension rod, and the middle part of the second backrest link is pivotally connected to the seat frame rear extension rod.

[0012] By adopting the above scheme, the introduction of the seat frame rear extension rod makes a four-bar mechanism formed among the seat frame rear extension rod, the first backrest link, the second backrest link and the backrest bracket, greatly improving the running stability.

[0013] Further, between the other end of the second backrest link and the fixed plate, there is also included: a fixed plate fixing rod, which is fixedly connected to the fixed plate; a fixed plate link, one end of the fixed plate link is pivotally connected to the other end of the second backrest link, and the other end is pivotally connected to the fixed plate fixing rod.

[0014] By adopting the above solution, it is possible to further restrict the backward movement of the rearmost end of the backrest assembly, meeting the zero-wall requirement.

[0015] Further, a front swing rod and a rear swing rod are also pivotally connected above the seat frame. An intermediate link is pivotally connected between the front swing rod and the rear swing rod. A front follower rod and a rear follower rod are pivotally connected to the fixed plate. A front driven rod and a rear driven rod are pivotally connected to the intermediate link. The end of the front driven rod is pivotally connected to the middle of the front follower rod. A follower link is pivotally connected between the end of the front follower rod and the middle of the rear driven rod. The end of the rear driven rod is pivotally connected to the middle of the rear follower rod. A driven link is pivotally connected between the end of the rear follower rod and the middle of the follower link.

[0016] By adopting the above solution, through the pivotal connection and interaction between multiple links, the intermediate link can be suspended and supported on the fixed plate so as to be movable back and forth, enabling the seat unit to move along a complex movement trajectory when changing its posture. This movement trajectory not only takes into account the angular changes of the backrest and the seat frame, but also considers the relative position and distance changes between them. It can provide a smoother and more natural posture change experience and reduce the discomfort of the user when changing the posture.

[0017] Further, the leg extension device includes: a footrest member; a leg telescopic link, which includes a first link, a second link, a third link, a fourth link, a fifth link and a sixth link. The rear end of the first link is pivotally connected to the seat frame, the front end of the first link is pivotally connected to the rear end of the second link, the front end of the second link is pivotally connected to the footrest member. The third link, the fourth link, the fifth link and the sixth link are sequentially pivotally connected end to end. The rear end of the third link is pivotally connected to the seat frame, the front end of the sixth link is pivotally connected to the footrest member. The middle of the fourth link is pivotally connected to the middle of the first link, and the middle of the fifth link is pivotally connected to the middle of the second link.

[0018] By adopting the above solution, the leg extension device is divided into three sections through the pivotal connections at two middle parts, greatly increasing the elongation length and being able to precisely adjust the position and angle of the leg support.

[0019] Further, a seat frame linkage rod is also pivotally connected between the intermediate link and the seat frame. The front end of the seat frame linkage rod is movably riveted to the third link, and the third link is movably riveted to the seat frame.

[0020] By adopting the above solution, the stability of the seat frame movement is further improved, and the seat frame and the leg stretching device are linked.

[0021] Furthermore, the fixed plate, the backrest assembly and the leg extension device are each provided with two groups, a first synchronization rod is provided between the two groups of the leg extension devices, and / or a second synchronization rod is provided between the two groups of the backrest assemblies, and / or a third synchronization rod is provided between the two groups of the fixed plates.

[0022] By adopting the above solution, when the seat unit changes its posture, the two groups of components can move simultaneously and coordinately, reducing the deviation and shaking caused by the movement of a single group of components, thereby improving the user's sense of security and comfort.

[0023] Furthermore, a driving device is hinged between the first synchronization rod and the second synchronization rod.

[0024] By adopting the above scheme, the seat unit can be smoothly transformed from a sitting position to a lying position or a TV position, and the leg extension device can be extended and retracted, thereby realizing intelligent control.

[0025] Furthermore, during the transition from the sitting position to the lying position, the backrest bracket moves forward and rotates, and the leg stretching device moves obliquely upward to the front side, and after the movement, the height of the leg stretching device is higher than the height of the backrest bracket.

[0026] By adopting the above solution, the user's sense of gravity is reduced, achieving a natural and comfortable lying effect.

[0027] In summary, the mechanical stretching device provided by the utility model has the following technical effects:

[0028] 1. The backrest bracket cannot move backwards when the seat changes from sitting to lying, which reduces the space required behind the seat unit when changing postures and achieves a zero-wall effect;

[0029] 2. Reducing the distance from the wall not only helps save space, but also enhances the stability of the seat unit during use. Since the shaking or instability caused by the large distance from the wall is reduced, users can enjoy the comfortable experience brought by the seat more at ease;

[0030] 3. The backrest can reach a large angle of 145°-160° when lying down, and the seat frame can also be properly raised by 20°-30°. This design allows users to get more comprehensive and even support when lying down, helps to reduce the pressure on the back and waist, and provides a more relaxing and comfortable lying experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1Schematic three-dimensional structure diagram of the sitting position according to an embodiment of the present utility model;

[0032] Figure 2 Schematic three-dimensional structure diagram of the TV position according to an embodiment of the present utility model;

[0033] Figure 3 Schematic three-dimensional structure diagram of the lying position according to an embodiment of the present utility model;

[0034] Figure 4 Schematic plan structure diagram of the sitting position according to an embodiment of the present utility model;

[0035] Figure 5 Schematic plan structure diagram of the TV position according to an embodiment of the present utility model;

[0036] Figure 6 Schematic plan structure diagram of the lying position according to an embodiment of the present utility model.

[0037] Among them, the meanings of the reference numerals are as follows: 1, fixed plate; 11, front follower rod; 12, rear follower rod; 13, follower link; 2, seat frame; 21, front swing rod; 22, rear swing rod; 23, intermediate link; 24, front driven rod; 25, rear driven rod; 26, driven link; 27, seat frame linkage rod; 3, backrest assembly; 31, backrest bracket; 32, first backrest link; 33, second backrest link; 34, seat frame extension rod; 35, fixed plate fixing rod; 36, fixed plate link; 4, leg extension device; 41, footrest; 42, leg telescopic link; 421, first link; 422, second link; 423, third link; 424, fourth link; 425, fifth link; 426, sixth link; 5, first synchronizing rod; 6, second synchronizing rod; 7, third synchronizing rod; 8, driving device; 81, push rod; 82, motor head. Detailed implementation manners

[0038] For better understanding and implementation, the technical solutions in the embodiments of the present utility model will be clearly and completely described and discussed below in conjunction with the drawings of the present utility model. Obviously, what is described here is only a part of the examples of the present utility model, not all of the examples. All other examples obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts belong to the protection scope of the present utility model.

[0039] For the convenience of understanding the embodiments of the present utility model, the following will further explain with specific examples in conjunction with the drawings, and each embodiment does not constitute a limitation to the embodiments of the present utility model.

[0040] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs. The terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model.

[0042] Example 1 of the present utility model is referred to Figures 1-6 As shown, a mechanical extension device is disclosed, which can be transformed at least between a sitting position, a TV position and a lying position, and includes: a fixed plate 1, a backrest assembly 3 and a leg extension device 4. Two sets of the fixed plate 1, the backrest assembly 3 and the leg extension device 4 are provided and symmetrically distributed on both sides of the seat unit. The fixed plate 1 in each side of the mechanical extension device can longitudinally extend along the front and rear direction of the movable seat, and the specific length can be selected according to actual needs to achieve sufficient seat length. Each side of the mechanical extension device is mounted on the inner side plate of the armrest part (not shown in the figure) by means of its respective fixed plate 1. Each fixed plate 1 is respectively attached to a common cross beam by means of a fixing piece, and the cross beam is located on the backrest side, that is, the rear part of the movable seat. The bottom of the armrest part directly supports on the ground, so that the mechanical extension device is "suspended" above the ground.

[0043] A seat frame 2 that can move back and forth is pivotally connected to the fixed plate 1. The backrest assembly 3 is pivotally connected to the rear part of the seat frame 2. The backrest assembly 3 includes a backrest bracket 31 for attaching a movable seat. The leg extension device 4 is pivotally connected to the front part of the seat frame 2. During the conversion from the sitting position to the lying position, the backrest bracket 31 moves forward and rotates, and the leg extension device 4 moves obliquely upward to the front side. After the movement, the height of the leg extension device 4 is higher than the height of the backrest bracket 31, reducing the user's sense of gravity and achieving a natural and comfortable lying flat effect. In the sitting position, the included angle between the surface of the backrest bracket 31 attaching the backrest and the fixed plate 1 ranges from 110° to 115°; the included angle between the fixed plate 1 and the seat frame 2 ranges from 5° to 10°. In the lying position, the included angle between the surface of the backrest bracket 31 attaching the backrest and the fixed plate 1 ranges from 145° to 160°; the included angle between the fixed plate 1 and the seat frame 2 ranges from 20° to 30°. When changing from the sitting position to the lying position, the rearmost part of the backrest bracket 31 does not have a tendency to move backward. Since the rearmost part of the backrest bracket 31 does not have a tendency to move backward, it can prevent the seat unit from moving excessively backward when changing postures, thus helping to reduce the distance from the wall. At the same time, the large-angle backward tilt design of 55° - 160° in the backrest bracket 311 and the appropriate elevation of 20° - 30° in the seat frame 2 help to provide a more relaxed and comfortable lying experience.

[0044] In the present Embodiment 1, the seat frame is used to carry the seat part of the movable seat. The backrest assembly 3 further includes a first backrest link 32, a second backrest link 33, and a seat frame rear extension bar 34. The seat frame rear extension bar 34 is fixed to the rear part of the seat frame. The seat frame rear extension bar 34 extends upward. The seat frame rear extension bar 34 can be integrally formed with the seat frame or can be a separate component fixedly connected to the seat frame. For example, it can be fixedly installed on the seat frame by means such as welding or riveting. Specifically, the backrest support 31 has a generally L-shaped structure. One end of the first backrest link 32 is pivotally connected to the front end of the backrest support 31, and the other end is pivotally connected to the seat frame 2. One end of the second backrest link 33 is pivotally connected to the rear end of the backrest support 31, and the second backrest link 33 is also pivotally connected to the seat frame 2. The seat frame rear extension bar 34 is fixedly connected to the seat frame 2. The other end of the first backrest link 32 is pivotally connected to the seat frame rear extension bar 34, and the middle part of the second backrest link 33 is pivotally connected to the seat frame rear extension bar 34. The introduction of the seat frame rear extension bar 34 forms a four-bar linkage mechanism among the seat frame rear extension bar 34, the first backrest link 32, the second backrest link 33, and the backrest support 31, greatly improving the running stability. Optionally, between the other end of the second backrest link 33 and the fixed plate 1, there are further a fixed plate fixed bar 35 and a fixed plate link 36. The fixed plate fixed bar 35 is fixedly connected to the fixed plate 1. One end of the fixed plate link 36 is pivotally connected to the other end of the second backrest link 33, and the other end is pivotally connected to the fixed plate fixed bar 35. Due to the existence of the fixed plate fixed bar 35, it is convenient to assemble the second synchronizing bar 6 between the fixed plate fixed bars 35 for assembling the mechanical extension devices on both sides. The assembly methods include but are not limited to screwing, welding, or integral connection.

[0045] In order to support the mechanical stretching device "suspended" above the ground, a front swing rod 21 and a rear swing rod 22 are also pivotally connected above the seat frame 2. An intermediate connecting rod 23 is pivotally connected between the front swing rod 21 and the rear swing rod 22, and is used to move the seat frame relative to the intermediate connecting rod 23 back and forth during the transformation process of the seat unit between the sitting position and the TV position. The intermediate connecting rod 23 remains substantially unchanged in position relative to the armrest portion. A front follower rod 11 and a rear follower rod 12 are pivotally connected to the fixing plate 1. A front driven rod 24 and a rear driven rod 25 are pivotally connected to the intermediate connecting rod 23. The end of the front driven rod 24 is pivotally connected to the middle of the front follower rod 11. A follower connecting rod 13 is pivotally connected between the end of the front follower rod 11 and the middle of the rear driven rod 25. The end of the rear driven rod 25 is pivotally connected to the middle of the rear follower rod 12. A driven connecting rod 26 is pivotally connected between the end of the rear follower rod 12 and the middle of the follower connecting rod 13. The driven connecting rod 26 and the follower connecting rod 13 are used to move the seat frame together with the intermediate connecting rod 23 relative to the armrest portion back and forth during the transformation process of the seat unit between the TV position and the lying position. Through the pivotal connection and interaction between multiple connecting rods, the intermediate connecting rod 23 can be suspended and supported on the fixing plate 1 so as to be movable back and forth, enabling the seat unit to move along a complex motion trajectory when changing its posture. This motion trajectory not only considers the angular changes of the backrest and the seat frame 2, but also considers the relative position and distance changes between them. It can provide a smoother and more natural posture transformation experience and reduce the discomfort of the user when changing posture.

[0046] The leg stretching device 4 includes a footrest member 41 and a leg telescopic connecting rod 42. The leg telescopic connecting rod 42 includes a first connecting rod 421, a second connecting rod 422, a third connecting rod 423, a fourth connecting rod 424, a fifth connecting rod 425 and a sixth connecting rod 426. The rear end of the first connecting rod 421 is pivotally connected to the seat frame 2. The front end of the first connecting rod 421 is pivotally connected to the rear end of the second connecting rod 422. The front end of the second connecting rod 422 is pivotally connected to the footrest member 41. The third connecting rod 423, the fourth connecting rod 424, the fifth connecting rod 425 and the sixth connecting rod 426 are sequentially pivotally connected end to end. The rear end of the third connecting rod 423 is pivotally connected to the seat frame 2. The front end of the sixth connecting rod 426 is pivotally connected to the footrest member 41. The middle of the fourth connecting rod 424 is pivotally connected to the middle of the first connecting rod 421. The middle of the fifth connecting rod 425 is pivotally connected to the middle of the second connecting rod 422. By the pivotal connections at the two middle parts, the leg stretching device 4 is divided into three sections, greatly increasing the elongation length and being able to accurately adjust the position and angle of the leg support. In the TV position, the footrest member 41 is parallel to the fixing plate 1. In the lying position, the included angle between the footrest member 41 and the fixing plate 1 is 15° - 18° to improve the leg comfort.

[0047] Optionally, a seat frame linkage rod 27 is also pivotally connected between the intermediate link 23 and the seat frame 2. The front end of the seat frame linkage rod 27 is movably riveted to the third link 423, and the third link 423 is movably riveted to the seat frame 2. This further improves the stability of the movement of the seat frame 2 and enables linkage between the seat frame 2 and the leg extension device 4.

[0048] To improve the synchronous operation of the mechanical extension devices on both sides, a first synchronizing rod 5 is provided between the leg extension devices 4, and / or a second synchronizing rod 6 is provided between the two backrest assemblies 3, and / or a third synchronizing rod 7 is provided between the two fixing plates 1. In Embodiment 1 of the present invention, the first synchronizing rod 5 is located between the two first links 421, the second synchronizing rod 6 is located between the two fixing plate rods 35 of the backrest, and the third synchronizing rod 7 is located between the two intermediate links 23.

[0049] In Embodiment 1 of the present invention, a driving device 8 is hinged between the first synchronizing rod 5 and the second synchronizing rod 6. Preferably, the driving device 8 adopts a push rod 81 motor. The push rod 81 motor includes a motor head 82 and a push rod 81. The push rod 81 can extend and retract relative to the electrode head. Among the motor head 82 and the push rod 81, one is hinged to the center of the first synchronizing rod 5, and the other is hinged to the center of the second synchronizing rod 6. When the push rod 81 motor contracts, it can drive the seat unit to be in the sitting position. When the push rod 81 motor extends, it can drive the seat unit to gradually change from the sitting position to the TV position and finally reach the lying position, thereby realizing a smooth transformation of the seat unit from the sitting position to the lying position or the TV position, as well as the extension and contraction of the leg extension device 4, achieving intelligent control.

[0050] In summary, a mechanical extension device provided by the present invention has the following technical effects:

[0051] 1. During the transformation from the sitting position to the lying position, the backrest bracket 31 cannot be displaced backward, reducing the rear space required for the seat unit to change its posture and achieving the zero-wall-touch effect;

[0052] 2. Reducing the wall-touch distance not only helps to save space but also enhances the stability of the seat unit during use. Since the factors of shaking or instability caused by too large a wall-touch distance are reduced, users can enjoy the comfort of the seat more reassuringly;

[0053] 3. When in the lying position, the backrest bracket 31 can be reclined at a large angle of 145° - 160°, and at the same time, the seat frame 2 is appropriately lifted by 20° - 30°. This design enables users to obtain more comprehensive and uniform support when lying down, helping to relieve the pressure on the back and waist and providing a more relaxing and comfortable lying experience.

[0054] The technical means disclosed by the solution of the present utility model are not limited to those disclosed by the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can be made, and these improvements and modifications are also regarded as the protection scope of the present utility model.

Claims

1. A mechanical stretching device capable of changing at least between a sitting position, a TV position and a lying position, characterized in that, Comprising: A fixed plate (1), above which a seat frame (2) that can move back and forth is pivotally connected; A backrest assembly (3), which is pivotally connected to the rear part of the seat frame (2), and the backrest assembly (3) includes a backrest bracket (31) for attaching a backrest; A leg extension device (4), which is pivotally connected to the front part of the seat frame (2); In the sitting position, the included angle range between the surface of the backrest bracket (31) attaching the backrest and the fixed plate (1) is 110° - 115°; the included angle range between the fixed plate (1) and the seat frame (2) is 5° - 10°; In the lying position, the included angle range between the surface of the backrest bracket (31) attaching the backrest and the fixed plate (1) is 145° - 160°; the included angle range between the fixed plate (1) and the seat frame (2) is 20° - 30°; When changing from the sitting position to the lying position, the rearmost part of the backrest bracket (31) has no tendency to move backward.

2. The mechanical extension device according to claim 1, characterized in that, The backrest assembly (3) further includes: A first backrest link (32), one end of which is pivotally connected to the front end of the backrest bracket (31), and the other end is pivotally connected to the seat frame (2); A second backrest link (33), one end of which is pivotally connected to the rear end of the backrest bracket (31), and the second backrest link (33) is also pivotally connected to the seat frame (2).

3. The mechanical stretching device according to claim 2, characterized in that, A seat frame rear extension rod (34) is further assembled between the seat frame (2) and the backrest assembly (3), the seat frame rear extension rod (34) is fixedly connected to the seat frame (2), the other end of the first backrest link (32) is pivotally connected to the seat frame rear extension rod (34), and the middle part of the second backrest link (33) is pivotally connected to the seat frame rear extension rod (34).

4. A mechanical extension device according to claim 2, wherein Between the other end of the second backrest link (33) and the fixed plate (1), there further includes: A fixed plate fixed rod (35), which is fixedly connected to the fixed plate (1); A fixed plate link (36), one end of which is pivotally connected to the other end of the second backrest link (33), and the other end is pivotally connected to the fixed plate fixed rod (35).

5. A mechanical extension device according to claim 1, wherein, Above the seat frame (2), a front swing rod (21) and a rear swing rod (22) are also pivotally connected. An intermediate connecting rod (23) is pivotally connected between the front swing rod (21) and the rear swing rod (22). A front follower rod (11) and a rear follower rod (12) are pivotally connected to the fixed plate (1). A front driven rod (24) and a rear driven rod (25) are pivotally connected to the intermediate connecting rod (23). The end of the front driven rod (24) is pivotally connected to the middle of the front follower rod (11). A follower connecting rod (13) is pivotally connected between the end of the front follower rod (11) and the middle of the rear driven rod (25). The end of the rear driven rod (25) is pivotally connected to the middle of the rear follower rod (12). A driven connecting rod (26) is pivotally connected between the end of the rear follower rod (12) and the middle of the follower connecting rod (13).

6. A mechanical extension device according to claim 5, characterized in that, The leg extension device (4) includes: A footrest member (41); A leg telescopic connecting rod (42), which includes a first connecting rod (421), a second connecting rod (422), a third connecting rod (423), a fourth connecting rod (424), a fifth connecting rod (425), and a sixth connecting rod (426). The rear end of the first connecting rod (421) is pivotally connected to the seat frame (2). The front end of the first connecting rod (421) is pivotally connected to the rear end of the second connecting rod (422). The front end of the second connecting rod (422) is pivotally connected to the footrest member (41). The third connecting rod (423), the fourth connecting rod (424), the fifth connecting rod (425), and the sixth connecting rod (426) are sequentially pivotally connected end to end. The rear end of the third connecting rod (423) is pivotally connected to the seat frame (2). The front end of the sixth connecting rod (426) is pivotally connected to the footrest member (41). The middle of the fourth connecting rod (424) is pivotally connected to the middle of the first connecting rod (421). The middle of the fifth connecting rod (425) is pivotally connected to the middle of the second connecting rod (422).

7. A mechanical extension device according to claim 6, characterized in that, A seat frame linkage rod (27) is also pivotally connected between the intermediate connecting rod (23) and the seat frame (2). The front end of the seat frame linkage rod (27) is movably riveted to the third connecting rod (423). The third connecting rod (423) is movably riveted to the seat frame (2).

8. A mechanical stretching device according to claim 1, characterized in that Two sets of the fixed plate (1), the backrest assembly (3), and the leg extension device (4) are provided. A first synchronizing rod (5) is provided between the two sets of the leg extension devices (4), and / or a second synchronizing rod (6) is provided between the two sets of the backrest assemblies (3), and / or a third synchronizing rod (7) is provided between the two sets of the fixed plates (1).

9. A mechanical extension device according to claim 8, wherein A driving device (8) is articulated between the first synchronizing rod (5) and the second synchronizing rod (6).

10. A mechanical extension device according to claim 1, characterized in that, During the conversion from the sitting position to the lying position, the backrest bracket (31) moves forward and rotates, and the leg extension device (4) moves obliquely upward to the front side. After the movement, the height of the leg extension device (4) is higher than the height of the backrest bracket (31).

Images