Mechanical extension device, seat unit and sofa

Abstract

The application discloses a mechanical stretching device, a seat unit and a sofa. The mechanical stretching device comprises a first auxiliary connecting rod, a first leg connecting rod, a third leg connecting rod, a fourth leg connecting rod and a fifth leg connecting rod. A driving assembly is arranged on the first leg connecting rod. The first mechanical stretching device is provided with a plurality of hinge joints, and the second leg connecting rod, the third leg connecting rod and the fourth leg connecting rod are directly connected through the hinge joints, so that the driving assembly can directly drive the plurality of leg connecting rods to move cooperatively. The first leg connecting rod is closer to the front end of the seat unit, and under the premise of meeting the installation distance of the driving assembly, the setting position of the mechanical stretching device on the base can be moved backward, so that a first distance is reserved on the front side of the first hinge joint, the accommodation space on the front side of the first mechanical stretching device is increased, and the length of the foot rest assembly and the length of the soft bag surface sleeve are increased, so that the soft bag surface sleeve is prevented from being pulled during the stretching of the mechanical stretching device.

Description

Technical Field

[0001] This application relates to the field of furniture technology, and in particular to mechanical extension devices, seating units, and sofas. Background Technology

[0002] Currently, functional sofas on the market include mechanical extension devices, which have sitting, TV, and reclining positions. The mechanical extension device includes a leg rest component. After changing from the sitting position to the TV position, the user's legs can be placed on the leg rest component.

[0003] The leg rest assembly has a leg rest board above it, and the surface of the leg rest board is usually covered with a soft cover. However, the mechanical extension device often pulls on the soft cover when changing between a sitting position and a TV position, thus affecting the user's leg experience on the leg rest board. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a mechanical extension device, a seat unit, and a sofa, which can prevent the upholstered cover from being pulled during the extension process of the mechanical extension device.

[0005] According to a first aspect embodiment of the present application, the mechanical extension device has a seated position and a TV position, including: A footrest assembly with a leg rest plate on top; The first auxiliary link is rotatably connected to the foot rest assembly; The second auxiliary link is rotatably connected to the foot support assembly; The first leg link has one end rotatably connected to the base, and the other end of the first leg link is movably connected to the second auxiliary link and the first auxiliary link respectively through the third leg link; The second leg link has one end rotatably connected to the base, and the other end movably connected to the first auxiliary link via the fourth leg link. During the process of the mechanical extension device changing from a seated position to a TV position, the third leg link pushes the footrest assembly forward through the first auxiliary link, and the third leg link pushes the footrest assembly to flip relative to the first auxiliary link through the second auxiliary link, so that the footrest assembly extends in front of the base; Also includes: A fifth leg link, one end of which is rotatably connected to the fourth leg link, and the other end of which is rotatably connected to the first leg link or the third leg link; A sixth leg link, one end of which is rotatably connected to the other end of the second leg link, and the other end of which is rotatably connected to the fifth leg link.

[0006] The mechanical extension device according to the embodiments of this application has at least the following beneficial effects: This application adds a fifth leg link and a sixth leg link, wherein the second leg link, the fourth leg link, the fifth leg link and the sixth leg link form a four-link structure, so that the fourth leg link is constrained and adjusted in motion trajectory by the fifth leg link and the second leg link. The fourth leg link is adjusted in motion trajectory in two directions, thereby reducing the swing amplitude of the first auxiliary link in motion, that is, by reducing the swing amplitude of the upholstered cover of the sofa in motion, the probability of the mechanical extension device pulling the upholstered cover in posture change is reduced.

[0007] The drive assembly is located on the first leg link, which facilitates the drive assembly to directly drive the coordinated movement of multiple leg links. Compared with the second leg link, the first leg link is closer to the front end of the seat unit. Under the premise of meeting the installation distance of the drive assembly, it is convenient to move the setting position of the mechanical extension device on the base backward, thereby reserving a first distance on the front side of the first hinge point, increasing the accommodating space on the front side of the first mechanical extension device, which is conducive to increasing the length of the footrest assembly and the length of the soft cover, so as to avoid pulling the soft cover during the extension of the mechanical extension device.

[0008] According to some embodiments of this application, the mechanical extension device further includes a drive assembly, which is fixedly connected to the first leg link, and the rotatable connection between the first leg link and the base is located in front of the rotatable connection between the second leg link and the base; The fourth leg link is rotatably connected to the first auxiliary link, and the third leg link is rotatably connected to the first auxiliary link. The rotatable connection between the fourth leg link and the first auxiliary link is located behind the rotatable connection between the third leg link and the first auxiliary link.

[0009] The drive assembly is fixedly connected to the first leg link. This structure increases the installation space of the drive assembly in the length direction of the sofa by moving the installation position of the drive assembly forward without increasing the length of the sofa. In other words, the sofa can be equipped with a motor with a longer stroke without changing the length of the base, in order to adapt to the popular trend of increasing the distance between sofa legs.

[0010] Because the rotatable connection between the first leg link and the base is located in front of the rotatable connection between the second leg link and the base, when the drive assembly is fixedly connected to the first leg link, the first leg link achieves a forward-positioned drive assembly. After the drive assembly is positioned forward, the rotatable connection of the first leg link on the base has sufficient space to move backward. This structure, while ensuring the travel of the drive assembly, provides more space for the secondary mounting plate when the mechanical extension device is in a seated position (after the mechanical extension device changes from the TV position to the seated position, the leg rest assembly retracts below the base, and the secondary mounting plate retracts below the base when the mechanical extension device is in the seated position), thus avoiding interference between the first leg link and the secondary mounting plate when the mechanical extension device is in the seated position.

[0011] This means that fixing the drive assembly to the first leg linkage not only increases the travel of the drive assembly but also increases the folding space of the leg rest assembly under the base. With the increased folding space under the base, the length of the leg rest assembly can also be increased accordingly. This increased length further reduces the probability that the soft-pack face shield covering the leg rest will be pulled during the mechanical extension device's transition from a seated to a TV position.

[0012] According to some embodiments of this application, the mechanical extension device further includes a mounting plate for mounting the crossbeam, the mounting plate and the first leg link being integrally formed and perpendicularly connected to each other, and the drive assembly being connected to the crossbeam.

[0013] According to some embodiments of this application, the mechanical extension device further includes a mounting plate, the mounting plate including a first plate and a second plate that are perpendicularly connected to each other, the first plate being rotatably connected to a second hinge point formed by the first leg link and the third leg link, and rotatably connected to a third hinge point formed by the first leg link and the fifth leg link; The second plate is used to mount the crossbeam, and the drive assembly is rotatably connected to the crossbeam.

[0014] According to some embodiments of this application, the first distance from the rotatable connection between the first leg link and the base to the front side of the base ranges from 60mm to 100mm.

[0015] According to some embodiments of this application, the foot support assembly includes a main mounting plate, an eighth leg link, and a secondary mounting plate, with one end of the eighth leg link rotatably connected to the main mounting plate; The sub-mounting plate includes a connecting part and an extension part that are connected at an angle to each other. A fourth hinge point is provided at the position where the connecting part and the extension part are connected to each other. The sub-mounting plate is rotatably connected to the other end of the eighth leg connecting rod through the fourth hinge point. The length of the extension part is in the range of 80mm-100mm.

[0016] According to some embodiments of this application, the main mounting plate is provided with a fifth hinge point, and the first auxiliary connecting rod is rotatably connected to the main mounting plate through the fifth hinge point; The footrest assembly also includes a ninth leg link, one end of which is rotatably connected to the first auxiliary link, and the other end of which is rotatably connected to the sub-mounting plate to increase the distance between the fourth hinge point and the fifth hinge point.

[0017] According to some embodiments of this application, the foot rest assembly further includes a tenth leg link, one end of which is rotatably connected to the main mounting plate, and the other end of which is rotatably connected to the auxiliary mounting plate, so as to increase the distance between the fourth hinge point and the fifth hinge point.

[0018] According to some embodiments of this application, the ninth leg link and the tenth leg link are both rotatably connected to the pivot on the connecting part, so that the ninth leg link, the tenth leg link and the auxiliary mounting plate are rotatably connected in the same position.

[0019] According to some embodiments of this application, the tenth leg link is formed as a bent bar with a bending portion. When the mechanical extension device retracts along the first direction, the bending portion is used to avoid the hinge point between the eighth leg link and the sub-mounting plate.

[0020] According to some embodiments of this application, a fourth limiting member is protruding from the surface of the fourth leg connecting rod; As the mechanical extension device changes from a seated position to a TV position, the fourth limiting member gradually approaches and contacts the fifth leg link to restrict the rotation of the fourth leg link. As the mechanical extension device changes from the TV position to the sitting position, the fourth limiting member gradually disengages from the fifth leg link.

[0021] According to a second aspect embodiment of the present application, the seat unit has a sitting position, a TV position, and a reclining position, and the seat unit includes: The aforementioned mechanical extension device; Base; Driver components; A base, which is movably connected to the base plate, and a limiting groove is provided on the front end of the base plate facing the foot support assembly; A backrest assembly, which is rotatably connected to the base and the pedestal; A supporting swing assembly is rotatably connected to the base; A connecting component is rotatably connected to the support swing component and the base. The base is movably connected to the base via the support swing component and the connecting component. The driving component drives the base to move relative to the base via the support swing component and the connecting component, and drives the backrest component to rotate. The foot support assembly further includes a second auxiliary link and a main mounting plate. The main mounting plate is rotatably connected to the first auxiliary link. One end of the second auxiliary link is rotatably connected to the third leg link, and the other end of the second auxiliary link is rotatably connected to the main mounting plate. A first limiting member is protruding from the surface of the second auxiliary link. During the process of the seat unit changing from a reclining position to a TV position, the drive assembly drives the base to move relative to the base in a first direction to adjust the angle of the base relative to the base, while the mechanical extension device remains extended; During the process of the seat unit changing from the TV position to the sitting position, the drive assembly drives the mechanical extension device to retract, and the first limiting member gradually approaches and embeds into the limiting groove to restrict the movement of the second auxiliary link.

[0022] The seat unit according to the embodiments of this application has at least the following beneficial effects: the second auxiliary link is provided with a first limiting member, which restricts the movement of the second auxiliary link when the seat unit is in a sitting position; the main mounting plate is provided with a second limiting member, which restricts the rotation of the main mounting plate when the seat unit is in a sitting position; the first auxiliary link is provided with a third limiting member, which restricts the movement of the first auxiliary link when the seat unit is in a TV position, thereby limiting the movement limit position of the mechanical extension device, ensuring that each leg link can perform a preset range of movement, avoiding overtravel, ensuring the safety of the seat unit, and improving the stability of the seat unit.

[0023] According to some embodiments of this application, the connecting assembly includes a first connecting rod and a second connecting rod, one end of the first connecting rod is rotatably connected to the support swing assembly, and the other end of the first connecting rod is rotatably connected to the base; one end of the second connecting rod is rotatably connected to the support swing assembly, and the other end of the second connecting rod is rotatably connected to the base. The seat unit also includes a linkage rod, one end of which is rotatably connected to the first connecting rod, and the other end of which is rotatably connected to the first leg link.

[0024] According to some embodiments of this application, the supporting swing assembly includes a first swing rod, a second swing rod, a third swing rod, a fourth swing rod, a fifth swing rod, a sixth swing rod, and a seventh swing rod. One end of the first swing rod is rotatably connected to the base, and the other end of the first swing rod is rotatably connected to one end of the second swing rod. The other end of the second swing rod is rotatably connected to the third swing rod, one end of the third swing rod is rotatably connected to one end of the fourth swing rod, and the other end of the fourth swing rod is rotatably connected to the base. The other end of the third swing rod is rotatably connected to one end of the fifth swing rod, the sixth swing rod is connected to the fifth swing rod, one end of the sixth swing rod is rotatably connected to the first swing rod, one end of the seventh swing rod is rotatably connected to the second swing rod, and the other end of the seventh swing rod is rotatably connected to the sixth swing rod.

[0025] According to some embodiments of this application, the first limiting member is fixedly connected to the second auxiliary connecting rod so that the first limiting member and the inner wall of the limiting groove are in rigid contact; Alternatively, the first limiting member is rotatably connected to the second auxiliary connecting rod so that the first limiting member and the inner wall of the limiting groove make rolling contact.

[0026] According to some embodiments of this application, a second limiting member is protruding from the surface of the main mounting plate; As the seat unit changes from the TV position to the sitting position, the second limiting member gradually approaches and contacts the second auxiliary link to restrict the rotation of the main mounting plate. As the seat unit changes from a sitting position to a TV position, the second limiting member gradually disengages from the second auxiliary link.

[0027] According to some embodiments of this application, the second limiting member is fixedly connected to the main mounting plate so that the second limiting member and the second auxiliary connecting rod are in rigid contact; Alternatively, the second limiting member is rotatably connected to the main mounting plate so that the second limiting member and the second auxiliary link make rolling contact.

[0028] According to some embodiments of this application, a third limiting member is protruding from the surface of the first auxiliary link; As the seat unit changes from a sitting position to a TV position, the third limiting member gradually approaches and contacts the third leg link to restrict the movement of the first auxiliary link. As the seat unit changes from the TV position to the sitting position, the third limiting member gradually disengages from the third leg link.

[0029] According to some embodiments of this application, the third limiting member is fixedly connected to the first auxiliary link, so that the third limiting member rigidly contacts the third leg link; Alternatively, the third limiting member is rotatably connected to the first auxiliary link, so that the third limiting member rolls into contact with the third leg link.

[0030] According to a third aspect embodiment of this application, the sofa includes the aforementioned seating unit; During the process of the seat unit changing from a sitting position to a TV position, the deflection angle of the first auxiliary link is less than 5°. During the process of the seat unit changing from the TV position to the sitting position, the deflection angle of the first auxiliary link is less than 5°.

[0031] The sofa according to the embodiments of this application has at least the following beneficial effects: during the process of the seat unit changing from a sitting position to a TV position, and during the process of changing from a TV position to a sitting position, the movement deflection angle of the first auxiliary link is less than 5°, so that the first auxiliary link moves or nearly moves, avoiding the first auxiliary link from contacting the ground due to large-scale rotation, and ensuring that the seat unit can be used with low-leg sofas with low base height.

[0032] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0033] The present application will be further illustrated below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments illustrated in the following drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application.

[0034] Figure 1 This is an inner front view of the mechanical extension device of the first embodiment of this application after it has been extended; Figure 2 This is a schematic diagram of the inner structure of the mechanical extension device after extension according to the first embodiment of this application; Figure 3 This is a schematic diagram of the outer structure of the mechanical extension device of the first embodiment of this application from one view after extension; Figure 4 This is a schematic diagram of the outer structure of the mechanical extension device of the first embodiment of this application from another perspective after it has been extended; Figure 5This is a front view of the outer side of the mechanical extension device of the first embodiment of this application after it has been retracted; Figure 6 This is an inner front view of the mechanical extension device of the first embodiment of this application after it has been retracted; Figure 7 The mechanical extension device of the first embodiment of this application Figure 6 A magnified view of part A in the middle; Figure 8 This is a schematic diagram of the inner structure of the mechanical extension device according to the second embodiment of this application; Figure 9 This is a schematic diagram of the outer structure of the mechanical extension device according to the second embodiment of this application; Figure 10 This is a structural schematic diagram of the seat unit in the seated position according to an embodiment of this application; Figure 11 This is a structural schematic diagram of the seat unit in the TV position according to an embodiment of this application; Figure 12 This is a schematic diagram of the mounting plate in the mechanical extension device of this application embodiment.

[0035] Figure label: 101. Base; 102. Drive assembly; 103. Backrest assembly; 104. Support swing assembly; 105. Base; 106. Leg rest; 200. Mechanical extension device; 201. First leg link; 202. Second leg link; 203. Third leg link; 204. Fourth leg link; 205. Fifth leg link; 206. Sixth leg link; 207. Second auxiliary link; 208. Eighth leg link; 209. Ninth leg link; 210. Tenth leg link; 211. First auxiliary link; 212. First hinge point; 213. Second hinge point; 214. Third hinge point; 215. Fourth hinge point; 216. Fifth hinge point; 217. Accommodation space; 218. Mounting plate; 2181. First plate; 2182. Second plate; 219. Foot support assembly; 220. Main mounting plate; 221. Secondary mounting plate; 222. Connecting part; 223. Extension part; 301. First limiting component; 302. Second limiting component; 303. Third limiting component; 304. Limiting groove; 305. Fourth limiting component; 401. First swing rod; 402. Second swing rod; 403. Third swing rod; 404. Fourth swing rod; 405. Fifth swing rod; 406. Sixth swing rod; 407. Seventh swing rod; 408. First connecting rod; 409. Second connecting rod; 410. Linkage rod. Detailed Implementation

[0036] The embodiments of this application are described in detail below with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0037] In the description of this application, it should be understood that the terms "center", "middle", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0038] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0039] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0040] In the description of this application, the use of terms such as "one embodiment," "some embodiments," "an example," "some instances," "some embodiments," "illustrative embodiment," "example," "specific example," and "some examples" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0041] like Figures 1-9As shown, this application embodiment provides a mechanical extension device 200, which is applied to a seat unit. The seat unit includes a base 101, a base 105, and a drive assembly 102. The base 105 is fixed in position, and the base 101 is movably connected to the base 105. When the seat unit changes posture, the base 101 moves relative to the base 105.

[0042] Furthermore, one end of the drive assembly 102 is connected to the base 105, and the other end is connected to the mechanical extension device 200. The drive assembly 102 can drive the mechanical extension device 200 to extend or retract, and can also drive the base 101 to move relative to the base 105. In addition, the drive assembly 102 of this application includes a push rod motor with a certain length.

[0043] Specifically, the seat unit can be adjusted to a sitting position, a TV position, and a reclining position through posture changes. During the transition from the sitting position to the TV position, the drive assembly 102 drives the mechanical extension device 200 to extend in the opposite direction along a first direction, causing the base 101 to move in the opposite direction relative to the base 105. During the transition from the TV position to the reclining position, the drive assembly 102 drives the base 101 to continue moving in the opposite direction relative to the base 105, thereby adjusting the angle of the base 101 relative to the base 105, during which the mechanical extension device 200 remains extended. During the transition from the reclining position to the TV position, the drive assembly 102 drives the base 101 to move in the first direction relative to the base 105, during which the mechanical extension device 200 remains extended. During the transition from the TV position to the sitting position, the drive assembly 102 drives the mechanical extension device 200 to retract in the first direction, causing the base 101 to return to its original position relative to the base 105 in the first direction. The first direction in this application is... Figure 1 , Figure 2 and Figure 6 The X direction in the diagram represents the rearward direction of the seat unit.

[0044] It is worth noting that the position where the drive assembly 102 is connected to the base 105 is already located at the rear of the base 105, and the connection position cannot be adjusted further to the rear of the seat unit. Since the drive assembly 102 has a certain length, sufficient installation distance needs to be reserved between the position where the mechanical extension device 200 is connected to the drive assembly 102 and the position where the base 105 is connected to the drive assembly 102, so as to ensure that the drive assembly 102 is installed normally.

[0045] Furthermore, the mechanical extension device 200 includes a first auxiliary link 211, a first leg link 201, a second leg link 202, a third leg link 203, a fourth leg link 204, a fifth leg link 205, a sixth leg link 206, a second auxiliary link 207, and a footrest assembly 219. A leg rest plate 106 is provided above the footrest assembly, and the surface of the leg rest plate 106 is provided with a soft cover.

[0046] The first auxiliary link 211 is approximately parallel to the base 101. Therefore, the first auxiliary link 211 has a front end facing the front of the seat unit and a rear end facing the rear of the seat unit. The front end of the first auxiliary link 211 is connected to the footrest assembly 219. The footrest assembly 219 is provided with a main mounting plate 220 and a secondary mounting plate 221 for supporting the user's feet. It is understood that, in order to improve the aesthetics and comfort of the footrest assembly 219, the surface of the leg rest plate 106 above the footrest assembly 219 is provided with a soft cover.

[0047] When the mechanical extension device 200 extends or retracts, the soft cover will also move in coordination with the rotation of the footrest assembly 219.

[0048] Meanwhile, in the first embodiment, the first leg link 201 is provided with a first hinge point 212, a second hinge point 213 and a third hinge point 214. The first leg link 201 is rotatably connected to the base 101 through the first hinge point 212, rotatably connected to the third leg link 203 through the second hinge point 213, and rotatably connected to the fifth leg link 205 through the third hinge point 214.

[0049] In addition, one end of the third leg link 203 is rotatably connected to the first auxiliary link 211, and the other end of the third leg link 203 is rotatably connected to the first leg link 201 through the second hinge point 213; one end of the fourth leg link 204 is rotatably connected to the first auxiliary link 211; and one end of the fifth leg link 205 is rotatably connected to the fourth leg link 204, and the other end of the fifth leg link 205 is rotatably connected to the first leg link 201 through the third hinge point 214.

[0050] Understandably, when the first leg link 201 rotates relative to the base 101, it can directly drive the third leg link 203 to rotate, and through the fifth leg link 205, directly drive the fourth leg link 204 to rotate. Since the first leg link 201 can directly drive several links to rotate together through three hinge points, the drive assembly 102 is located on the first leg link 201, thereby optimizing the power transmission path of the drive assembly 102, facilitating the stability of the mechanical extension device 200's movement, and improving the synchronization of the movement of each leg link in the mechanical extension device 200.

[0051] During the process of the seat unit changing from the TV position to the sitting position, the mechanical extension device 200 retracts along the first direction. The drive assembly 102 drives the first leg link 201 to rotate relative to the base 101. The first leg link 201 drives the third leg link 203 and the fourth leg link 204 to rotate synchronously. The third leg link 203 and the fourth leg link 204 drive the first auxiliary link 211 to move. The first auxiliary link 211 moves to drive the sub-mounting plate 221 and the soft cover on the sub-mounting plate 221 to roll inward to the bottom of the first auxiliary link 211 and approach the first leg link 201, thereby completing the retraction process of the mechanical extension device 200.

[0052] In addition, such as Figure 8 and Figure 9 As shown, the difference between the second embodiment and the first embodiment is that one end of the fifth leg link 205 is rotatably connected to the fourth leg link 204, while the other end of the fifth leg link 205 is rotatably connected to the third leg link 203. Since the fifth leg link 205 is not rotatably connected to the first leg link 201, the number of hinge points on the first leg link 201 is reduced. Specifically, in the second embodiment, the number of hinge points on the first leg link 201 is two.

[0053] Although the first leg link 201 in the second embodiment has two hinge points, during its rotation relative to the base, the first leg link 201 can directly drive the third leg link 203 to rotate, and can also directly drive the fourth leg link 204 to rotate through the third leg link 203 and the fifth leg link 205. Therefore, the drive assembly 102 can also be disposed on the first leg link 201, thereby optimizing the power transmission path of the drive assembly 102 and facilitating the stability of the movement of the mechanical extension device 200.

[0054] It is worth noting that if the length of the secondary mounting plate 221 is too short, the length of the soft cover on the secondary mounting plate 221 will also be too short. When the mechanical extension device 200 extends, the soft cover may be overstretched due to insufficient length, resulting in damage to the soft cover and affecting the normal use of the seat unit. In addition, if the length of the secondary mounting plate 221 is increased, the secondary mounting plate 221 may easily cause structural interference with the leg linkages of the mechanical extension device 200 after it is rolled inward.

[0055] To address the aforementioned issues, this application provides several hinge points on the first leg link 201, which is positioned relatively forward, to facilitate the installation of the drive assembly 102 on the first leg link 201. Although the drive assembly 102 requires a certain installation distance, since the first leg link 201 is positioned relatively forward, the connection position of the mechanical extension device 200 on the base 101 can still be appropriately moved backward, allowing a first distance to be reserved between the position of the first hinge point 212 and the front end of the base 101.

[0056] Furthermore, since the first hinge point 212 reserves a first distance L, the mechanical extension device 200 can form a larger accommodating space 217 on the front side of the first leg connecting rod 201 after retraction, which is convenient to accommodate the longer secondary mounting plate 221 and soft cover. The increased length of the secondary mounting plate 221 and soft cover can effectively prevent the soft cover from being pulled when the mechanical extension device 200 extends.

[0057] The contents of this application are described in detail below with reference to specific embodiments. It should be noted that the following description is merely illustrative and not a specific limitation of this application.

[0058] like Figures 1-4 As shown, in some embodiments, the mechanical extension device 200 further includes a mounting plate 218, which is disposed at the end of the first leg link 201 and perpendicularly connected to the first leg link 201. Specifically, the mounting plate 218 may be integrally formed with the first leg link 201.

[0059] Furthermore, the mounting plate 218 is used to mount the crossbeam, and the drive assembly 102 is rotatably connected to the crossbeam and can drive the first leg link 201 to rotate relative to the base 101 via the crossbeam.

[0060] Meanwhile, since a single mechanical extension device 200 is insufficient to effectively support the user's legs, mechanical extension devices 200 are provided on both opposite sides of the seat unit. The crossbeam can connect the first leg link 201 of the two mechanical extension devices 200, thereby enabling the two mechanical extension devices 200 to form a synchronously moving whole, ensuring support. It is understandable that, since the mounting plate 218 and the first leg link 201 are integrally formed, the mechanical extension device 200 can use a single first leg link 201 combined with the crossbeam to connect to the drive assembly 102, simplifying the overall structure.

[0061] In addition, such as Figure 12As shown, the mechanical extension device 200 can also employ an independently mounted plate 218. This mounted plate 218 includes a first plate 2181 and a second plate 2182, which are perpendicularly connected to each other. The first plate 2181 is rotatably connected, on one hand, to the second hinge point 213 formed by the first leg link 201 and the third leg link 203, and on the other hand, to the third hinge point 214 formed by the first leg link 201 and the fifth leg link 205. Furthermore, the second plate 2182 is used to mount the crossbeam, and the drive assembly 102 is rotatably connected to the crossbeam. Understandably, the independently installed mounting plate 218 here can be flexibly structurally adjusted to allow the second plate 2182 to be positioned relatively far back, so that the position of the crossbeam is also relatively far back, avoiding the crossbeam and drive assembly 102 from occupying the accommodating space 217 in front of the first leg link 201, so that the accommodating space 217 can accommodate the longer secondary mounting plate 221 and the soft cover.

[0062] like Figure 1 As shown, in some embodiments, compared to conventional seat units, this application increases the range of the first distance L to 60mm-100mm, which can effectively increase the range of the accommodating space 217 and facilitate increasing the length of the secondary mounting plate 221 and the soft cover.

[0063] like Figures 1-6 As shown, in some embodiments, the mechanical extension device 200 further includes a second leg link 202 and a sixth leg link 206. The second leg link 202 is rotatably connected to the other end of the fourth leg link 204. One end of the second leg link 202 is rotatably connected to the base 101, and the other end of the second leg link 202 is rotatably connected to one end of the sixth leg link 206. The other end of the sixth leg link 206 is rotatably connected to the fifth leg link 205. The second leg link 202 and the fifth leg link 205 also support the first auxiliary link 211, thereby further improving the movement stability of the first auxiliary link 211 and ensuring that the seat unit is stable and wobble-free during use.

[0064] Furthermore, when the mechanical extension device 200 retracts along the first direction, the first leg link 201 drives the second leg link 202 to rotate via the fifth leg link 205 and the sixth leg link 206.

[0065] Specifically, the first mechanical extension device 200 is directly rotatably connected to the third leg link 203 via the second hinge point 213. The first mechanical extension device 200 directly rotates the fifth leg link 205 via the third hinge point 214, and directly rotatably connects the fourth leg link 204 and the second leg link 202 via the fifth leg link 205 and the sixth leg link 206. This allows the first leg link 201 to directly drive the second leg link 202, the third leg link 203, and the fourth leg link 204 to rotate in tandem via its rotation relative to the base 101. Under the combined support of the first leg link 201, the second leg link 202, the third leg link 203, and the fourth leg link 204, the first auxiliary link 211 can move smoothly.

[0066] It is worth noting that the second leg link 202, the sixth leg link 206, the fifth leg link 205, and the fourth leg link 204 form a four-bar linkage mechanism, which allows the fourth leg link 204 to constrain and adjust its movement trajectory through the fifth leg link 205 and the second leg link 202. The fourth leg link 204 can reduce the swing amplitude of the first auxiliary link 211 in the process of pushing the footrest assembly 219 forward by adjusting the movement trajectory in two directions. That is, by reducing the swing amplitude of the upholstered cover during the movement of the sofa, the seat unit pulls on the upholstered cover.

[0067] In some embodiments, the distance between the hinge point of the second leg link 202 and the base 101 and the front end of the base 101 is greater than the distance between the hinge point of the first leg link 201 and the base 101 and the front end of the base 101. The first leg link 201 is closer to the front end of the seat unit than the second leg link 202, thus providing a longer mounting distance for the drive assembly 102 to ensure the travel of the drive assembly 102. Simultaneously, the greater distance between the hinge point of the second leg link 202 and the base 101 and the front end of the base 101, and the greater distance between the hinge point of the first leg link 201 and the base 101 and the front end of the base 101, allows the secondary mounting plate 221 to be positioned further back after the mechanical extension device 200 retracts. This ensures that the soft-pack cover can be extended during the inward rolling of the footrest assembly 219, preventing the footrest assembly 219 from pulling on the soft-pack cover when it unfolds.

[0068] If the drive assembly 102 is located on the second leg link 202, the first leg link 201 will still compress the installation range of the accommodating space 217 to ensure the installation distance of the drive assembly 102, which is not conducive to increasing the range of the accommodating space 217. In this application, the drive assembly 102 is located on the first leg link 201, which makes it easier to move the overall installation position of the mechanical extension device 200 on the base 101 backward, thereby increasing the accommodating space 217 and facilitating the length of the auxiliary mounting plate 221 and the soft cover.

[0069] Meanwhile, the fourth leg link 204 is rotatably connected to the first auxiliary link 211, and the third leg link 203 is rotatably connected to the first auxiliary link 211. The rotatable connection between the fourth leg link 204 and the first auxiliary link 211 is located behind the rotatable connection between the third leg link 203 and the first auxiliary link 211.

[0070] The forward placement of the third leg link 203 enables the first auxiliary link 211 to have a faster response speed; while the rear placement of the fourth leg link 204 increases the distance between the fourth leg link 204 and the footrest assembly 219, further reducing the impact of the swing of the first auxiliary link 211 on the position of the footrest assembly 219 in the height direction.

[0071] like Figures 6-7 As shown, in some embodiments, the foot rest assembly 219 includes a second auxiliary link 207, a main mounting plate 220, an eighth leg link 208, and a secondary mounting plate 221. One end of the second auxiliary link 207 is rotatably connected to the third leg link 203, and the other end of the second auxiliary link 207 is rotatably connected to the main mounting plate 220. One end of the eighth leg link 208 is rotatably connected to the main mounting plate 220, and the other end of the eighth leg link 208 is rotatably connected to the secondary mounting plate 221. The second auxiliary link 207 supports the main mounting plate 220. Under the support of the second auxiliary link 207, as the first auxiliary link 211 moves, the first auxiliary link 211 can drive the main mounting plate 220 to rotate, thereby causing the secondary mounting plate 221 to rotate, allowing the secondary mounting plate 221 to perform an inward or outward movement.

[0072] Furthermore, the sub-mounting plate 221 includes a connecting portion 222 and an extension portion 223. The connecting portion 222 and the extension portion 223 are connected at an angle to each other, and a fourth hinge point 215 is provided at the position where the connecting portion 222 and the extension portion 223 are connected to each other. The sub-mounting plate 221 is rotatably connected to the eighth leg connecting rod 208 through the fourth hinge point 215.

[0073] Specifically, the connecting part 222 is used to connect with other leg links of the mechanical extension device 200 to ensure that the sub-mounting plate 221 can rotate, while the extension part 223 is used to support the user's feet.

[0074] It is worth noting that the length of the extension portion 223 in this application ranges from 80mm to 100mm, which is much longer than the length of the sub-mounting plate 221 of the seat unit currently on the market. This increases the length of the soft cover on the sub-mounting plate 221 and prevents the soft cover from being pulled when the mechanical extension device 200 extends.

[0075] like Figures 5-7As shown, in some embodiments, the main mounting plate 220 is provided with a fifth hinge point 216, and the first auxiliary link 211 is rotatably connected to the main mounting plate 220 through the fifth hinge point 216.

[0076] Furthermore, the footrest assembly 219 also includes a ninth leg link 209, one end of which is rotatably connected to the first auxiliary link 211, and the other end of which is rotatably connected to the sub-mounting plate 221. Because the ninth leg link 209 has a certain length, it can increase the distance between the fourth hinge point 215 and the fifth hinge point 216, which is beneficial for increasing the overall length of the mechanical extension device 200 after the sub-mounting plate 221 is deployed.

[0077] In some embodiments, the foot rest assembly 219 further includes a tenth leg link 210, one end of which is rotatably connected to the main mounting plate 220, and the other end of which is rotatably connected to the sub-mounting plate 221. Since the tenth leg link 210 has a certain length, it can also increase the distance between the fourth hinge point 215 and the fifth hinge point 216, which is beneficial for increasing the overall length of the mechanical extension device 200 after the sub-mounting plate 221 is deployed.

[0078] In some embodiments, the ninth leg link 209 and the tenth leg link 210 are both rotatably connected to the pivot on the connecting portion 222, such that the ninth leg link 209, the tenth leg link 210 and the auxiliary mounting plate 221 are rotatably connected in the same position.

[0079] Specifically, when the size of the secondary mounting plate 221 is too large, even if the surface of the secondary mounting plate 221 is covered with a soft cover, the secondary mounting plate 221 will still change the overall shape of the footrest assembly 219, affecting the overall aesthetics of the seat unit. Furthermore, an excessively large secondary mounting plate 221 is difficult to roll inward and store in the accommodating space 217. Due to the limited size of the secondary mounting plate 221, to save space on the secondary mounting plate 221, the ninth leg link 209, the tenth leg link 210, and the secondary mounting plate 221 are rotatably connected at the same position.

[0080] In some embodiments, the first auxiliary link 211 is directly rotatably connected to the secondary mounting plate 221, without the ninth leg link 209 and the tenth leg link 210. To ensure the distance between the fourth hinge point 215 and the fifth hinge point 216, the length of the first auxiliary link 211 is increased. After the first auxiliary link 211 is rotatably connected to the main mounting plate 220, the first auxiliary link 211 continues to extend a certain distance toward the secondary mounting plate 221, thereby rotatably connecting with the secondary mounting plate 221.

[0081] In some embodiments, the tenth leg link 210 is formed as a bent rod, and a bending portion is provided in the middle of the tenth leg link 210. When the mechanical extension device 200 retracts along the first direction, the bending portion can avoid the hinge point of the eighth leg link 208 and the auxiliary mounting plate 221, thereby avoiding structural interference.

[0082] In some embodiments, a fourth limiting member 305 protrudes from the surface of the fourth leg link 204. As the seat unit changes from a sitting position to a TV position, the fourth limiting member 305 gradually approaches and contacts the fifth leg link 205, thereby restricting the rotation of the fourth leg link 204; as the seat unit changes from a TV position to a sitting position, the fourth limiting member 305 gradually moves away from the fifth leg link 205.

[0083] like Figure 10 and Figure 11 As shown in the illustration, this application provides a seat unit, which includes a base 105, a base 101, a backrest assembly 103, a support swing assembly 104, a connecting assembly, and the aforementioned mechanical extension device 200. The backrest assembly 103 is rotatably connected to the base 105 and the base 101. The support swing assembly 104 is rotatably connected to the base 105. The connecting assembly is rotatably connected to the support swing assembly 104 and the base 101. The base 101 is movably connected to the base 105 via the support swing assembly 104 and the connecting assembly. The drive assembly 102 drives the base 101 to move relative to the base 105 and drives the backrest assembly 103 to rotate via the support swing assembly 104 and the connecting assembly.

[0084] In some embodiments, the support swing assembly 104 is rotatably connected to the base 105 and is used to support the base 101. The connecting assembly is rotatably connected to the support swing assembly 104 and the base 101, so the base 101 is movably connected to the base 105 through the support swing assembly 104 and the connecting assembly.

[0085] Furthermore, the support swing assembly 104 and the connecting assembly act on different stages of the seat unit's posture change. Therefore, the support swing assembly 104 and the connecting assembly move relatively independently, ensuring the support effect of the support swing assembly 104 and improving the stability of the seat unit.

[0086] Specifically, during the process of the seat unit changing from a sitting position to a TV position, the mechanical extension device 200 extends along the first direction, the supporting swing assembly 104 is relatively stationary with respect to the base 105, and the connecting assembly rotates relative to the base 101. The base 101 moves relative to the base 105 under the action of the connecting assembly. During the process of the seat unit changing from a TV position to a reclining position, the mechanical extension device 200 remains extended, the supporting swing assembly 104 rotates relative to the base 105, the connecting assembly and the base 101 are relatively stationary, and the base 101 moves relative to the base 105 under the action of the supporting swing assembly 104.

[0087] In some embodiments, the seat unit further includes a linkage 410, the first end of which is rotatably connected to the first leg link 201, and the second end of which is rotatably connected to the connecting assembly. The linkage 410 enables the mechanical extension device 200 and the connecting assembly to move in coordination.

[0088] Specifically, during the process of the seat unit changing from a sitting position to a TV position, the drive assembly 102 drives the mechanical extension device 200 to extend, and the mechanical extension device 200 and the connecting assembly move synchronously through the linkage rod 410.

[0089] In some embodiments, the supporting swing assembly 104 includes a first swing rod 401, a second swing rod 402, a third swing rod 403, a fourth swing rod 404, a fifth swing rod 405, a sixth swing rod 406, and a seventh swing rod 407. One end of the first swing rod 401 is rotatably connected to the base 105, the other end of the first swing rod 401 is rotatably connected to one end of the second swing rod 402, the other end of the second swing rod 402 is rotatably connected to the third swing rod 403, one end of the third swing rod 403 is rotatably connected to one end of the fourth swing rod 404, and the other end of the fourth swing rod 404 is rotatably connected to the base 105. Since both the first swing rod 401 and the fourth swing rod 404 are rotatably connected to the base 105, the supporting swing assembly 104 is rotatably connected to the base 105.

[0090] Furthermore, the other end of the third swing rod 403 is rotatably connected to one end of the fifth swing rod 405, the sixth swing rod 406 is connected to the fifth swing rod 405, and one end of the sixth swing rod 406 is rotatably connected to the first swing rod 401. One end of the seventh swing rod 407 is rotatably connected to the second swing rod 402, and the other end of the seventh swing rod 407 is rotatably connected to the sixth swing rod 406. Therefore, the supporting swing assembly 104 is integrally formed as a linkage mechanism.

[0091] In some embodiments, the connecting assembly includes a first connecting rod 408 and a second connecting rod 409. One end of the first connecting rod 408 is connected to the end of the fifth swing rod 405, and the other end of the first connecting rod 408 is rotatably connected to the base 101. One end of the second connecting rod 409 is rotatably connected to the fifth swing rod 405, and the other end of the second connecting rod 409 is rotatably connected to the base 101. Since both the first connecting rod 408 and the second connecting rod 409 are used to rotatably connect the fifth swing rod 405 and the base 101, the first connecting rod 408, the second connecting rod 409, the base 101, and the fifth swing rod 405 form a stable four-bar linkage, with the fifth swing rod 405 serving as the supporting foundation for the base 101.

[0092] Furthermore, the second end of the linkage rod 410 is rotatably connected to the first connecting rod 408 to ensure that the mechanical extension device 200 and the connecting assembly move synchronously.

[0093] like Figures 1-4 As shown, the surface of the second auxiliary link 207 is provided with a first limiting member 301, and correspondingly, the base 101 is provided with a limiting groove 304 facing the front end of the foot rest assembly 219.

[0094] During the process of the seat unit changing from a reclining position to a TV position, the drive assembly 102 drives the base 101 to move relative to the base 105 in a first direction, thereby adjusting the angle of the base 101 relative to the base 105. During this process, the mechanical extension device 200 remains extended. During the process of the seat unit changing from a TV position to a sitting position, the drive assembly 102 drives the mechanical extension device 200 to retract, and the first limiting member 301 gradually approaches and embeds into the limiting groove 304, thereby restricting the movement of the second auxiliary link 207.

[0095] In some embodiments, the first limiting member 301 is fixedly connected to the second auxiliary connecting rod 207, so that the first limiting member 301 and the inner wall of the limiting groove 304 are in rigid contact, thereby achieving the limiting.

[0096] Alternatively, the first limiting member 301 is rotatably connected to the second auxiliary connecting rod 207, so that the first limiting member 301 and the inner wall of the limiting groove 304 roll into contact, thereby achieving the limiting.

[0097] In some embodiments, a second limiting member 302 is protruding from the surface of the main mounting plate 220. When the seat unit changes from the TV position to the sitting position, the second limiting member 302 gradually approaches and contacts the second auxiliary link 207, thereby restricting the rotation of the main mounting plate 220; when the seat unit changes from the sitting position to the TV position, the second limiting member 302 gradually disengages from the second auxiliary link 207, thereby releasing the limiting.

[0098] In some embodiments, the second limiting member 302 is fixedly connected to the main mounting plate 220, so that the second limiting member 302 and the second auxiliary link 207 are in rigid contact, thereby achieving the limiting.

[0099] Alternatively, the second limiting member 302 is rotatably connected to the main mounting plate 220, so that the second limiting member 302 and the second auxiliary connecting rod 207 roll into contact, thereby achieving the limiting.

[0100] In some embodiments, a third limiting member 303 is protruding from the surface of the first auxiliary link 211. When the seat unit changes from a sitting position to a TV position, the third limiting member 303 gradually approaches and contacts the third leg link 203, thereby restricting the movement of the first auxiliary link 211; when the seat unit changes from a TV position to a sitting position, the third limiting member 303 gradually disengages from the third leg link 203, thereby releasing the limiting.

[0101] In some embodiments, the third limiting member 303 is fixedly connected to the first auxiliary link 211, so that the third limiting member 303 rigidly contacts the third leg link 203, thereby achieving limiting.

[0102] Alternatively, the third limiting member 303 is rotatably connected to the first auxiliary link 211, so that the third limiting member 303 rolls into contact with the third leg link 203, thereby achieving the limiting.

[0103] This application embodiment provides a sofa, which includes the aforementioned seat unit. During the process of the seat unit changing from a sitting position to a TV position, the deflection angle of the first auxiliary link 211 is less than 5°; during the process of the seat unit changing from a TV position to a sitting position, the deflection angle of the first auxiliary link 211 is also less than 5°, ensuring that the first auxiliary link 211 moves in a moving or near-moving manner, thereby driving the main mounting plate 220 to rotate.

[0104] Furthermore, since the first auxiliary link 211 moves approximately, it effectively avoids the first auxiliary link 211 from contacting the ground due to large-scale rotation, ensuring that the seat unit of this application can be used with low-profile sofas with a low base 101, thus improving versatility.

[0105] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

Claims

1. A mechanical extension device, having a seated position and a TV position, including: A footrest assembly with a leg rest plate on top; The first auxiliary link is rotatably connected to the foot rest assembly; The second auxiliary link is rotatably connected to the foot support assembly; The first leg link has one end rotatably connected to the base, and the other end of the first leg link is movably connected to the second auxiliary link and the first auxiliary link respectively through the third leg link; The second leg link has one end rotatably connected to the base, and the other end movably connected to the first auxiliary link via the fourth leg link. During the process of the mechanical extension device changing from a seated position to a TV position, the third leg link pushes the footrest assembly forward through the first auxiliary link, and the third leg link pushes the footrest assembly to flip relative to the first auxiliary link through the second auxiliary link, so that the footrest assembly extends in front of the base; Its characteristic is that it further includes: A fifth leg link, one end of which is rotatably connected to the fourth leg link, and the other end of which is rotatably connected to the first leg link or the third leg link; A sixth leg link, one end of which is rotatably connected to the other end of the second leg link, and the other end of which is rotatably connected to the fifth leg link.

2. The mechanical extension device according to claim 1, characterized in that, The mechanical extension device further includes a drive assembly, which is fixedly connected to the first leg link, and the rotatable connection between the first leg link and the base is located in front of the rotatable connection between the second leg link and the base. The fourth leg link is rotatably connected to the first auxiliary link, and the third leg link is rotatably connected to the first auxiliary link. The rotatable connection between the fourth leg link and the first auxiliary link is located behind the rotatable connection between the third leg link and the first auxiliary link.

3. The mechanical extension device according to claim 2, characterized in that, The mechanical extension device also includes a mounting plate for mounting the crossbeam. The mounting plate and the first leg connecting rod are integrally formed and connected perpendicularly to each other. The drive assembly is connected to the crossbeam.

4. The mechanical extension device according to claim 2, characterized in that, The mechanical extension device further includes a mounting plate, which includes a first plate and a second plate that are perpendicularly connected to each other. The first plate is rotatably connected to a second hinge point formed by the first leg link and the third leg link, and is also rotatably connected to a third hinge point formed by the first leg link and the fifth leg link. The second plate is used to mount the crossbeam, and the drive assembly is rotatably connected to the crossbeam.

5. The mechanical extension device according to claim 1, characterized in that, The first distance from the rotatable connection point of the first leg link to the base to the front side of the base ranges from 60mm to 100mm.

6. The mechanical extension device according to any one of claims 1-5, characterized in that, The foot support assembly includes a main mounting plate, an eighth leg connecting rod, and a secondary mounting plate, with one end of the eighth leg connecting rod rotatably connected to the main mounting plate; The sub-mounting plate includes a connecting part and an extension part that are connected at an angle to each other. A fourth hinge point is provided at the position where the connecting part and the extension part are connected to each other. The sub-mounting plate is rotatably connected to the other end of the eighth leg connecting rod through the fourth hinge point. The length of the extension part is in the range of 80mm-100mm.

7. The mechanical extension device according to claim 6, characterized in that, The main mounting plate is provided with a fifth hinge point, and the first auxiliary connecting rod is rotatably connected to the main mounting plate through the fifth hinge point; The footrest assembly also includes a ninth leg link, one end of which is rotatably connected to the first auxiliary link, and the other end of which is rotatably connected to the sub-mounting plate to increase the distance between the fourth hinge point and the fifth hinge point.

8. The mechanical extension device according to claim 7, characterized in that, The foot rest assembly also includes a tenth leg link, one end of which is rotatably connected to the main mounting plate, and the other end of which is rotatably connected to the auxiliary mounting plate, thereby increasing the distance between the fourth hinge point and the fifth hinge point.

9. The mechanical extension device according to claim 8, characterized in that, The ninth leg link and the tenth leg link are both rotatably connected to the pivot on the connecting part, so that the ninth leg link, the tenth leg link and the auxiliary mounting plate are rotatably connected in the same position.

10. The mechanical extension device according to claim 8, characterized in that, The tenth leg link is formed as a bent bar with a bending part. When the mechanical extension device retracts in the first direction, the bending part is used to avoid the hinge point of the eighth leg link and the auxiliary mounting plate.

11. The mechanical extension device according to claim 1, characterized in that, The surface of the fourth leg connecting rod is provided with a fourth limiting member; As the mechanical extension device changes from a seated position to a TV position, the fourth limiting member gradually approaches and contacts the fifth leg link to restrict the rotation of the fourth leg link. As the mechanical extension device changes from the TV position to the sitting position, the fourth limiting member gradually disengages from the fifth leg link.

12. The seat unit, with its mechanical extension device further having a reclining position, is characterized in that, include: The mechanical extension device as described in any one of claims 1-11; Base; Driver components; A base, which is movably connected to the base plate, and a limiting groove is provided on the front end of the base plate facing the foot support assembly; A backrest assembly, which is rotatably connected to the base and the pedestal; A supporting swing assembly is rotatably connected to the base; A connecting assembly is rotatably connected to the support swing assembly and the base, and the base is movably connected to the base via the support swing assembly and the connecting assembly. The support swing assembly and the connecting assembly are used to drive the base to move relative to the base and to drive the backrest assembly to rotate. The foot support assembly further includes a second auxiliary link and a main mounting plate. The main mounting plate is rotatably connected to the first auxiliary link. One end of the second auxiliary link is rotatably connected to the third leg link, and the other end of the second auxiliary link is rotatably connected to the main mounting plate. A first limiting member is protruding from the surface of the second auxiliary link. During the process of the seat unit changing from a reclining position to a TV position, the drive assembly drives the base to move relative to the base in a first direction to adjust the angle of the base relative to the base, while the mechanical extension device remains extended; During the process of the seat unit changing from the TV position to the sitting position, the drive assembly drives the mechanical extension device to retract, and the first limiting member gradually approaches and embeds into the limiting groove to restrict the movement of the second auxiliary link.

13. The seat unit according to claim 12, characterized in that, The connecting assembly includes a first connecting rod and a second connecting rod. One end of the first connecting rod is rotatably connected to the support swing assembly, and the other end of the first connecting rod is rotatably connected to the base. One end of the second connecting rod is rotatably connected to the support swing assembly, and the other end of the second connecting rod is rotatably connected to the base. The seat unit also includes a linkage rod, one end of which is rotatably connected to the first connecting rod, and the other end of which is rotatably connected to the first leg link.

14. The seat unit according to claim 12, characterized in that, The supporting swing assembly includes a first swing rod, a second swing rod, a third swing rod, a fourth swing rod, a fifth swing rod, a sixth swing rod, and a seventh swing rod. One end of the first swing rod is rotatably connected to the base, and the other end of the first swing rod is rotatably connected to one end of the second swing rod. The other end of the second swing rod is rotatably connected to the third swing rod, one end of the third swing rod is rotatably connected to one end of the fourth swing rod, and the other end of the fourth swing rod is rotatably connected to the base. The other end of the third swing rod is rotatably connected to one end of the fifth swing rod, the sixth swing rod is connected to the fifth swing rod, and one end of the sixth swing rod is rotatably connected to the first swing rod. One end of the seventh swing rod is rotatably connected to the second swing rod, and the other end of the seventh swing rod is rotatably connected to the sixth swing rod.

15. The seat unit according to claim 12, characterized in that, The first limiting member is fixedly connected to the second auxiliary connecting rod so that the first limiting member and the inner wall of the limiting groove are in rigid contact; Alternatively, the first limiting member is rotatably connected to the second auxiliary connecting rod so that the first limiting member and the inner wall of the limiting groove make rolling contact.

16. The seat unit according to claim 12, characterized in that, The surface of the main mounting plate is provided with a second limiting member. As the seat unit changes from the TV position to the sitting position, the second limiting member gradually approaches and contacts the second auxiliary link to restrict the rotation of the main mounting plate. As the seat unit changes from a sitting position to a TV position, the second limiting member gradually disengages from the second auxiliary link.

17. The seat unit according to claim 16, characterized in that, The second limiting member is fixedly connected to the main mounting plate so that the second limiting member and the second auxiliary connecting rod are in rigid contact; Alternatively, the second limiting member is rotatably connected to the main mounting plate so that the second limiting member and the second auxiliary link make rolling contact.

18. The seat unit according to claim 12, characterized in that, The surface of the first auxiliary connecting rod is provided with a third limiting member; As the seat unit changes from a sitting position to a TV position, the third limiting member gradually approaches and contacts the third leg link to restrict the movement of the first auxiliary link. As the seat unit changes from the TV position to the sitting position, the third limiting member gradually disengages from the third leg link.

19. The seat unit according to claim 18, characterized in that, The third limiting member is fixedly connected to the first auxiliary connecting rod so that the third limiting member rigidly contacts the third leg connecting rod; Alternatively, the third limiting member is rotatably connected to the first auxiliary link, so that the third limiting member rolls into contact with the third leg link.

20. A sofa, characterized in that, Includes the seat unit as described in any one of claims 12-19; During the process of the seat unit changing from a sitting position to a TV position, the deflection angle of the first auxiliary link is less than 5°. During the process of the seat unit changing from the TV position to the sitting position, the deflection angle of the first auxiliary link is less than 5°.

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