MECHANICAL STRETCHING DEVICE FOR MOVABLE SEAT UNIT AND SEAT UNIT

Abstract

The present disclosure relates to a movable seat with a mechanical stretching device. The movable seat includes a frame assembly connected to the mechanical stretching device and the frame assembly includes a seat frame configured to support a seating portion of the movable seat, an armrest frame fixedly connected to the seat frame, and a backrest frame configured to support a backrest of the movable seat, where the backrest frame includes a lower frame section and an upper frame section, the upper frame section transitions to the lower section via a stepped portion, and a rear part of the armrest frame includes a curved extending section, and a gap is formed between the armrest frame and the upper frame section.

Claims

1. A movable seat, comprising: a mechanical stretching device; and a frame assembly connected to the mechanical stretching device, wherein the frame assembly comprises: a seat frame configured to support a seating portion of the movable seat; an armrest frame fixedly connected to the seat frame; and a backrest frame configured to support a backrest of the movable seat, wherein the backrest frame comprises a lower frame section and an upper frame section, the upper frame section transitions to the lower section via a stepped portion, and a rear part of the armrest frame comprises a curved extending section, and a gap is formed between the armrest frame and the upper frame section.

2. The movable seat according to claim 1, wherein the stepped portion comprises a lower edge that extends in a substantially arcuate shape.

3. The movable seat according to claim 1, wherein the mechanical stretching device comprises: a base assembly fixedly supported on a ground; a side plate movably supported above the base assembly, wherein the side plate is configured to connect to the seating portion of the movable seat; and a backrest assembly pivotally connected to a rear portion of the side plate, wherein in a transition of the movable seat from one position to another position, the backrest assembly moves forward along with the side plate and the gap between the armrest frame and the upper frame section remains substantially unchanged.

4. The movable seat according to claim 1, wherein a gap is formed between the lower frame section and the seat frame, and wherein in a transition of the movable seat from one position to another position, the gap between the lower frame section and the seat frame remains substantially unchanged.

5. The movable seat according to claim 3, wherein the backrest assembly pivotally connected to a rear portion of the side plate, wherein the backrest assembly comprises a backrest mounting member and a backrest connecting rod assembly; wherein the mechanical stretching device further comprises a central coupling element movably connected between the side plate and the backrest assembly; wherein the backrest connecting rod assembly comprises a first backrest connecting rod and a second backrest connecting rod, an upper end of the first backrest connecting rod is hinged to a front end of the backrest mounting member at a first pivot point, a front end portion of the second backrest connecting rod is hinged to the side plate at a second pivot point, and a middle portion of the second backrest connecting rod is hinged to a middle portion of the first backrest connecting rod.

6. The movable seat according to claim 5, wherein the mechanical stretching device further comprises a leg stretching device pivotally connected to a front portion of the side plate, wherein the leg stretching device comprises a first footrest element configured to attach a footrest; wherein the mechanical stretching device transitions at least between a sitting position and a lying position, wherein in the sitting position, the first footrest element is retracted beneath the seating portion; wherein in the lying position, the backrest of the movable seat is reclined and the first footrest element is extended forward relative to the sitting position; and wherein a distance between the first pivot point and the second pivot point is reduced in the lying position compared to the sitting position.

7. The movable seat according to claim 6, wherein relative movement between the central coupling element and the side plate drives the backrest connecting rod assembly to compress and expand so that the backrest mounting member rotates rearward and forward about the first pivot point.

8. The movable seat according to claim 7, wherein the backrest connecting rod assembly further comprises a third backrest connecting rod, wherein a lower end of the first backrest connecting rod is hinged to the central coupling element at a third pivot point, an upper end of the third backrest connecting rod is hinged to a rear end of the backrest mounting member, and a lower end of the third backrest connecting rod is hinged to a rear end of the second backrest connecting rod.

9. The movable seat according to claim 8, wherein in transition of the movable seat from the sitting position to the lying position, relative movement between the side plate and the central coupling element increases a distance between the second pivot point and the third pivot point and compresses the backrest connecting rod assembly.

10. The movable seat according to claim 6, wherein the leg stretching device further comprises a second footrest element, wherein in the sitting position, both the first footrest element and the second footrest element are retracted beneath the seating portion; and wherein in the lying position, the backrest is reclined, and a highest point of the footrest is higher than a highest point of the backrest, wherein both the first footrest element and the second footrest element extend forward and upward, and the second footrest element is positioned in front of the first footrest element.

11. The movable seat according to claim 10, wherein the first footrest element and the second footrest element are connected via a footrest connection element, wherein the footrest connection element comprises a first connecting element and a second connecting element that are hinged to each other.

12. The movable seat according to claim 3, wherein the mechanical stretching device further comprises a front swing rod, a rear swing rod, a seat coupling element, and a side plate coupling element, wherein lower ends of the front swing rod and the rear swing rod are pivotally connected to the base assembly, and upper ends of the front swing rod and the rear swing rod are connected to the side plate via the central coupling element, the seat coupling element, and the side plate coupling element, and wherein movement of the side plate relative to the base assembly drives movement of the backrest assembly and the leg stretching device relative to the side plate, and enables the movable seat to transit between the sitting position and the lying position.

13. The movable seat according to claim 6, wherein in the lying position, a highest point of the first footrest element is higher than a highest point of the backrest mounting member.

14. The movable seat according to claim 3, wherein the mechanical stretching device further comprises: an electric driving device coupled between the base assembly and the side plate.

15. A mechanical stretching device in a movable seat, comprising: a base assembly fixedly supported on a ground; a side plate movably supported above the base assembly, wherein the side plate is configured to connect to the seating portion of the movable seat; and a backrest assembly pivotally connected to a rear portion of the side plate, wherein the backrest assembly comprises a backrest mounting member and a backrest connecting rod assembly, wherein the backrest connecting rod assembly comprises a first backrest connecting rod and a second backrest connecting rod, an upper end of the first backrest connecting rod is hinged to a front end of the backrest mounting member at a first pivot point, a front end of the second backrest connecting rod is hinged to the side plate at a second pivot point, and the middle portion of the second backrest connecting rod is hinged to the first backrest connecting rod, wherein the backrest connecting rod assembly compresses to rotate the backrest mounting member rearward about the first pivot point and the backrest connecting rod assembly expands to rotate the backrest mounting member forward about the first pivot point.

16. The mechanical stretching device according to claim 15, further comprising: a central coupling element movably connected between the side plate and the backrest assembly, wherein relative movement between the central coupling element and the side plate drives the backrest connecting rod assembly to compress so that the backrest mounting member rotates rearward about the first pivot point and the backrest connecting rod assembly moves forward relative to the ground toward the front of the movable seat.

17. The mechanical stretching device according to claim 16, comprising: a leg stretching device pivotally connected to a front portion of the side plate, wherein the leg stretching device comprises a first footrest element configured to attach a footrest, wherein the mechanical stretching device transitions at least between a sitting position and a lying position, wherein in the sitting position, the first footrest element is retracted beneath the seating portion; wherein in the lying position, the backrest of the movable seat is reclined and the first footrest element is extended forward relative to the sitting position; and wherein a distance between the first pivot point and the second pivot point is reduced in the lying position compared to the sitting position.

18. The mechanical stretching device according to claim 17, wherein the backrest connecting rod assembly further comprises a third backrest connecting rod, wherein a lower end of the first backrest connecting rod is hinged to the central coupling element at a third pivot point, an upper end of the third backrest connecting rod is hinged to a rear end of the backrest mounting member, and a lower end of the third backrest connecting rod is hinged to a rear end of the second backrest connecting rod, and wherein in transition of the movable seat from the sitting position to the lying position, relative movement between the side plate and the central coupling element increases a distance between the second pivot point and the third pivot point and compresses the backrest connecting rod assembly.

19. The mechanical stretching device according to claim 18, wherein the leg stretching device further comprises a second footrest element, wherein in the sitting position, both the first footrest element and the second footrest element are retracted beneath the seating portion; wherein in the lying position, the backrest is reclined, and a highest point of the footrest is higher than a highest point of the backrest, wherein both the first footrest element and the second footrest element extend forward and upward, and the second footrest element is positioned in front of the first footrest element; and wherein the first footrest element and the second footrest element are connected via a footrest connection element, wherein the footrest connection element comprises a first connecting element and a second connecting element that are hinged to each other.

20. The mechanical stretching device according to claim 19, wherein the mechanical stretching device further comprises a front swing rod, a rear swing rod, a seat coupling element, and a side plate coupling element, wherein lower ends of the front swing rod and the rear swing rod are pivotally connected to the base assembly, and upper ends of the front swing rod and the rear swing rod are connected to the side plate via the central coupling element, the seat coupling element, and the side plate coupling element, wherein movement of the side plate relative to the base assembly drives movement of the backrest assembly and the leg stretching device relative to the side plate, and enables the movable seat to transit between the sitting position and the lying position, wherein in the lying position, a highest point of the first footrest element is higher than a highest point of the backrest mounting member, and wherein the mechanical stretching device further comprises: an electric driving device coupled between the base assembly and the side plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Implementations of the present disclosure will be described below in detail with reference to the accompanying drawings.

[0008] FIG. 1 is a stereoscopic view of a mechanical stretching device in a sitting state according to one or more examples of the present disclosure.

[0009] FIG. 2 is a stereoscopic view of a mechanical stretching device in a relaxing state according to one or more examples of the present disclosure.

[0010] FIG. 3 is a stereoscopic view of a mechanical stretching device in a lying state according to one or more examples of the present disclosure.

[0011] FIG. 4 is a side view of a mechanical stretching device in a sitting state according to one or more examples of the present disclosure.

[0012] FIG. 5 is a side view of a mechanical stretching device in a relaxing state according to one or more examples of the present disclosure.

[0013] FIG. 6 is a side view of a mechanical stretching device in a lying state according to one or more examples of the present disclosure.

[0014] FIG. 7 is a schematic structural view of a footrest extension mechanism according to one or more examples of the present disclosure.

[0015] FIG. 8 is a schematic structural view of a seat stretchable device in a sitting state according to one or more examples of the present disclosure.

[0016] FIG. 9 is a schematic structural view of a seat stretchable device in a stretched lying state according to one or more examples of the present disclosure.

[0017] FIG. 10 is a schematic structural view of the other side of FIG. 8.

[0018] FIG. 11 is a schematic structural view of the other side of FIG. 9.

[0019] FIG. 12 is a perspective view of a mechanical stretching device together with a frame assembly shown in the sitting position according to one or more examples of the present disclosure.

[0020] FIG. 13 is a perspective view of the mechanical stretching device shown in the sitting position according to one or more examples of the present disclosure.

[0021] FIG. 14 is a side view of the mechanical stretching device shown in FIG. 13 according to one or more examples of the present disclosure.

[0022] FIG. 15 is a partial side view of the mechanical stretching device shown in FIG. 13 according to one or more examples of the present disclosure.

[0023] FIG. 16 is a side view of a seat unit, shown in the sitting position according to one or more examples of the present disclosure.

[0024] FIG. 17 is a side view of the seat unit shown in FIG. 16 displayed in the TV-viewing position according to one or more examples of the present disclosure.

[0025] FIG. 18 is a side view of the seat unit shown in FIG. 16 displayed in the lying position according to one or more examples of the present disclosure.

[0026] FIG. 19 is a side view of a seat unit shown in the sitting position according to one or more examples of the present disclosure.

[0027] FIG. 20 is a side view of the seat unit shown in FIG. 19, displayed in the TV-viewing position, according to one or more examples of the present disclosure.

[0028] FIG. 21 is a side view of the seat unit shown in FIG. 19 displayed in the lying position according to one or more examples of the present disclosure.

[0029] FIG. 22 is a side view of a seat unit shown in the sitting position according to one or more examples of the present disclosure.

[0030] FIG. 23 is a side view of a seat unit shown in the TV-viewing position according to one or more examples of the present disclosure.

[0031] FIG. 24 is a side view of a seat unit shown in the lying position according to one or more examples of the present disclosure.

[0032] FIG. 25 is a side view of a seat unit, shown in the sitting position according to one or more examples of the present disclosure.

[0033] FIG. 26 is a side view of the seat unit shown in FIG. 25 displayed in the TV-viewing position according to one or more examples of the present disclosure.

[0034] FIG. 27 is a side view of the seat unit shown in FIG. 25 displayed in the lying position according to one or more examples of the present disclosure.

[0035] FIG. 28 is a side view of the mechanical stretching device in the sitting position according to one or more examples of the present disclosure.

[0036] FIG. 29 is a side view of the mechanical stretching device shown in the TV-viewing position according to one or more examples of the present disclosure.

[0037] FIG. 30 is a side view of the mechanical stretching device shown in the lying position according to one or more examples of the present disclosure.

[0038] FIG. 31 is a side view of a seat unit shown in the sitting position as shown in FIG. 22 with the wall and the ground according to one or more examples of the present disclosure.

[0039] FIG. 32 is a side view of a seat unit shown in the TV-viewing position as shown in FIG. 23 with the wall and the ground according to one or more examples of the present disclosure.

[0040] FIG. 33 is a side view of a seat unit shown in the lying position as shown in FIG. 24 with the wall and the ground according to one or more examples of the present disclosure.

[0041] FIG. 34 is a side view of a seat unit shown in the sitting position as shown in FIG. 25 with the wall and the ground according to one or more examples of the present disclosure.

[0042] FIG. 35 is a side view of a seat unit shown in the TV-viewing position as shown in FIG. 26 with the wall and the ground according to one or more examples of the present disclosure.

[0043] FIG. 36 is a side view of a seat unit shown in the lying position as shown in FIG. 27 with the wall and the ground according to one or more examples of the present disclosure.

DETAILED DESCRIPTION

[0044] The present disclosure is described with reference to examples and corresponding drawings. The described examples are only part but not all of the examples of the present disclosure. Based on the examples in the present disclosure, all other examples obtained by those ordinary skilled in the art without any inventive work belong to the protection scope of the present disclosure.

[0045] The terms one embodiment or an embodiment as used herein refer to a particular feature, structure, or characteristic that may be included in at least one implementation of the present disclosure. It should be understood that the directional or positional terms such as upper, lower, left, right, top, and bottom are based on the orientation shown in the accompanying drawings. These terms are used for ease of description and simplification, and are not intended to indicate or imply that the referenced device or component must have a specific orientation or be constructed and operated in a particular direction. Therefore, such terms should not be interpreted as limitations of the present disclosure.

[0046] It shall be understood that, the terms first and second are used solely for descriptive purposes and should not be construed as indicating relative importance or implying a specific number of the mentioned technical features. Features labeled as first or second may explicitly or implicitly include one or more of such features. Furthermore, these terms are intended to distinguish between similar elements and do not necessarily define a sequential order. It should be understood that such elements may be interchanged where appropriate, allowing the embodiments of the present disclosure to be implemented in sequences other than those illustrated or described herein.

[0047] Unless otherwise specified, the terms front or front of the seat unit or front of the mechanical stretching device refer to the direction toward the leg stretching device relative to the seat unit; correspondingly, the terms rear or rear of the seat unit or rear of the mechanical stretching device refer to the direction toward the backrest assembly relative to the seat unit.

[0048] The description of numerals used in this disclosure may include: [0049] 1 linkage support [0050] 1 seat portion assembly [0051] 11 base assembly [0052] 111 Lateral rail [0053] 112 Front transverse rail [0054] 113 Rear transverse rail [0055] 12 Support structure [0056] 121 Base [0057] 1211 Lateral rail [0058] 1212 Front transverse rail [0059] 1213 Rear transverse rail [0060] 1112 Front Swing Rod [0061] 1113 Rear Swing Rod [0062] 122 First support element [0063] 123 Second support element [0064] 124 Base coupling component [0065] 1241 Back coupling element [0066] 1242 Seat coupling element [0067] 1243 Lateral plate coupling [0068] 13 linkage structure [0069] 131 Lateral plate [0070] 132 First coupling element [0071] 133 Second coupling element [0072] 134 Third coupling element [0073] 14 Transmission structure [0074] 140 Side plate [0075] 141 First transmissive element [0076] 142 Second transmissive element [0077] 15 Central coupling element [0078] 16 Seat coupling element [0079] 17 Side Plate coupling element [0080] 18 First transmissive element [0081] 19 Second transmissive element [0082] 2 Back mechanism [0083] 2 Backrest assembly [0084] 20 Backrest Mounting Member [0085] 21 Backrest connection element [0086] 22 Back connecting rod [0087] 220 Backrest connecting rod assembly [0088] 221 First backrest connecting rod [0089] 222 Second backrest connecting rod [0090] 223 Third backrest connecting rod [0091] 3 Leg stretching device [0092] 31 First connecting rod [0093] 32 Second connecting rod [0094] 321 First connecting point [0095] 322 Second connecting point [0096] 33 Third connecting rod [0097] 34 Fourth connecting rod [0098] 341 Footrest connecting point [0099] 342 Coupling rod connecting point [0100] 342 Connection element connecting point [0101] 35 First footrest element [0102] 351 Second connecting rod connecting point [0103] 352 linkage point [0104] 36 Coupling rod [0105] 37 Second footrest element [0106] 371 First limit element [0107] 38 Footrest connection element [0108] 381 First connection element [0109] 382 Second connection element [0110] 383 Vertical section [0111] 39 Footrest plate component [0112] 391 First footrest plate [0113] 392 Second footrest plate [0114] 4 Electric driving device [0115] 40 Motor Crossbar [0116] 41 Motor Head [0117] 42 Motor Slide Rail [0118] 43 Motor slider [0119] 44 Motor Connecting Rod

[0120] FIG. 1 to FIG. 3 schematically illustrate an example of a mechanical stretching

[0121] device for a movable seat unit. The mechanical stretching device includes: a linkage support 1, a back mechanism 2, and a leg stretching structure 3.

[0122] Specifically, the linkage support 1 includes a support structure 12 and a linkage structure 13.

[0123] The support structure 12 includes a base 121, a first support element 122, a second support element 123, and a base coupling component 124. The base 121 includes two lateral rails 1211 in a mirror symmetry on a left side and a right side, and optionally further includes a front transverse rail 1212 and a rear transverse rail 1213 for connecting the two lateral rails 1211. A lower end of the first support element 122 is hinged to a front end of the lateral rail 1211, a lower end of the second support element 123 is hinged to a rear end of the lateral rail 1211, and the base coupling component 124 is provided between the first support element 122 and the second support element 123.

[0124] The linkage structure 13 includes a lateral plate 131, a first coupling element 132, a second coupling element 133, and a third coupling element 134, a middle of the second coupling element 133 is rotatably connected to the lateral plate 131, one end of the second coupling element 133 is connected to one end of the first coupling element 132, the other end of the first coupling element 132 is connected to the first support element 122, the other end of the second coupling element 133 is connected to one end of the third coupling element 134, and the other end of the third coupling element 134 is pivotally connected to the leg stretching structure 3.

[0125] Specifically, the back mechanism 2 includes a backrest connection element 21 attached to a backrest and a back connecting rod 22 pivotally connected to the backrest connection element. The backrest connection element 21 is hinged to a rear end of the lateral plate 131 of the linkage structure 3.

[0126] Specifically, the leg stretching structure 3 is composed of multiple connecting rods that are pivotally connected to one another, where a rear end of a first connecting rod 31 is hinged to the lateral plate 131 of the linkage structure 13, a front end of the first connecting rod 31 is hinged to a rear end of a second connecting rod 32, a rear end of a third connecting rod 33 is hinged to a front end of the lateral plate 131, a front end of the third connecting rod 33 is hinged to a rear end of a fourth connecting rod 34, a front end of each of the second connecting rod 32 and the fourth connecting rod 34 is hinged to a first footrest element 35, an end of the second connecting rod 32 close to the first connecting rod 31 is provided with a first connecting point 321, and the second connecting rod 32 is hinged to a middle of the third connecting rod 33 at the first connecting point 321.

[0127] Specifically, the base coupling component 124 includes: a back coupling element 1241, a seat coupling element 1242, and a lateral plate coupling element 1243, where the back coupling element 1241 is provided with multiple pivotal points; and the back coupling element is respectively hinged to the back connecting rod 22 of the back mechanism 2, the lateral plate 131 of the linkage structure 13, the seat coupling element 1242 and the second support element 123 by means of different pivotal points. One end of the seat coupling element 1242 is connected to the first support element 122 by means of the lateral plate coupling element 1243, and the other end of the seat coupling element 1242 is connected to the back coupling element 1241.

[0128] Specifically, the linkage support 1 further includes a transmission structure 14, the transmission structure 14 includes a first transmissive element 141 and a second transmissive element 142 that are connected to one another, the first transmissive element is connected to a driving device, the second transmissive element is connected to the first connecting rod 31 of the leg stretching structure 3, and the driving device drives a movement of the linkage support by means of the transmission structure. In some examples, the driving device may be a manual driving device; and in other examples, the driving device may be a motor driving device, and the motor driving device may be a push rod motor or slider motor driving device.

[0129] According to the example, the movement of the linkage support 1 drives the back mechanism 2 and the leg stretching device 3 for stretching or retracting, such that the mechanical stretching device can implement a sequential conversion or a reverse sequential conversion of the seat unit from a sitting state shown in FIG. 1 to a relaxing state shown in FIG. 2 and then to a lying state shown in FIG. 3. In the sitting state, the first footrest element 35 is folded below a seating portion; in the relaxing state, the first footrest element 35 is stretched to be in front of the seating portion; and in the lying state, an angle between the backrest and the seating portion is increased relative to the relaxing state, and the first footrest element 35 extends further forward and upward than in the relaxing state, as shown in FIG. 6, such that a height of a highest point of the leg stretching structure 3 relative to a horizontal plane is greater than that of a highest point of the back mechanism 2 relative to the horizontal plane, with a height difference being in a range between 200 mm and 400 mm, and is preferably 265 mm.

[0130] An included angle is formed between an end surface of the footrest element and the horizontal direction, and an included angle is formed between the seating portion or a contact surface on which the lateral plate 131 is coupled to the seating portion and the horizontal direction.

[0131] As shown in FIG. 5 to FIG. 6, the included angle between the footrest element in the relaxing state and the horizontal direction is less than the included angle between the footrest element in the lying state and the horizontal direction. Specifically, in the relaxing state, the angle formed between the footrest element and the horizontal direction is in a range between 8 and 20, preferably between 12 and 19, and more preferably between 14 and 15; and in the lying state, the angle formed between the footrest element and the horizontal direction is in a range between 9 and 23, preferably 14 and 21, and more preferably 18 and 19.

[0132] In the lying state, the angle formed between the seating portion and the horizontal direction is in a range between 8 and 17, and preferably between 13 and 16.

[0133] FIG. 7 to FIG. 11 illustrate a second alternative example of the present disclosure.

[0134] An example further provides a mechanical stretching device for a movable seat unit. The difference between the second example and the first example mainly lies in the design of the leg stretching structure. According to the second example, the leg stretching mechanism 3 is constructed as a footrest extension mechanism as shown in FIG. 7, including: a first connecting rod 31, a second connecting rod 32, a third connecting rod 33, a fourth connecting rod 34, a first footrest element 35, a coupling rod 36, a second footrest element 37 and a footrest connection element 38.

[0135] One end of the second connecting rod 32 is hinged to the first footrest element 35, the other end of the second connecting rod 32 is hinged to the first connecting rod 31, the first connecting rod 31 is hinged to the linkage support 1 of the seat unit, one end of the fourth connecting rod 34 is hinged to the second footrest element 37, the other end of the fourth connecting rod 34 is hinged to the third connecting rod 33, the first footrest element 35 is hinged to one end of the coupling rod 36, and the other end of the coupling rod 36 is hinged to a middle of the fourth connecting rod 34.

[0136] The footrest connection element 38 includes a first connection element 381 and a second connection element 382, one end of the first connection element 381 is hinged to a middle of the second footrest element 37, the other end of the first connection element 381 is hinged to one end of the second connection element 382, the other end of the second connection element 382 is hinged to a middle of the second connecting rod 32, and a middle of the second connection element 382 is hinged to the middle of the fourth connecting rod 34.

[0137] In the example, the first footrest element 35 is hinged to the fourth connecting rod 34 by means of the coupling rod 36, the fourth connecting rod is connected to the second footrest element, and the first footrest element 35 is not connected to the fourth connecting rod, such that the first footrest element and the second footrest element are retracted or stretched more flexibly. The first footrest element 35, the coupling rod 36, the fourth connecting rod 34, the second connection element 382, and the second connecting rod 32 are formed into a five-rod structure, which implements the effect that the first footrest element can be drawn close to or spaced apart from the second footrest element more flexibly, increases a distance between the first footrest element and the second footrest element that are spaced apart, and increases an extended length of the second footrest element.

[0138] Specifically, the middle of the second footrest element 37 is provided with a first limit element 371, and when the first limit element 371 abuts against the second connection element 382, the second footrest element 37 is retracted to a limit position. In the example, the first limit element 371 limits a maximum retracted position of the second footrest element, to avoid a phenomenon that the second footrest element is not retracted to a predetermined position and is loose. Meanwhile, a footrest surface of the second footrest element and a footrest surface of the first footrest element are in the same vertical plane, thereby improving the aesthetics of the seat in the retracted state.

[0139] Specifically, an end of the second connecting rod 32 close to the first connecting rod 31 is provided with a first connecting point 321, the second connecting rod 32 is hinged to a middle of the third connecting rod 33 at the first connecting point 321, and the third connecting rod 33 is connected to the linkage support 1. The second connecting rod 32 is intersected with the third connecting rod 33.

[0140] Specifically, an end of the second connecting rod 32 close to the first footrest element 35 is provided with a second connecting point 322, and the second connecting rod 32 is connected to the second connection element 382 at the second connecting point 322. In the example, the first connection element 381 and the second connection element 382 are used to connect and support the second footrest element 37, and the second footrest element 37, the first connection element 381, the second connection element 382, and the fourth connecting rod 34 are formed into a foldable and stretchable four-rod structure to support and drive the second footrest element 37 for stretching.

[0141] Specifically, an end of the fourth connecting rod 34 close to the second footrest element 37 is sequentially provided with a footrest connecting point 341, a coupling rod connecting point 342, and a connection element connecting point 343; and the fourth connecting rod 34 is connected to the second footrest element 37 at the footrest connecting point 341, the fourth connecting rod 34 is connected to the coupling rod 36 at the coupling rod connecting point 342, the fourth connecting rod 34 is connected to the second connection element 382 at the connection element connecting point 343, and the coupling rod connecting point 342 is provided between the footrest connecting point 341 and the connection element connecting point 343.

[0142] Specifically, a second connecting rod connecting point 351 and a linkage point 352 are arranged on the first footrest element 35, and a distance from the linkage point 352 to the coupling rod connecting point 342 is greater than that from the linkage point 352 to the second connecting rod connecting point 351. Specifically, the distance from the linkage point 352 to the second connecting rod connecting point 351 is less than that from the linkage point 352 to the coupling rod connecting point 342, such that the second connecting rod 32 drives the second connecting rod connecting point 351 to move downward relative to the linkage point 352 when the first footrest element 35 is stretched, the footrest surface of the first footrest element 35 smoothly rotates to a horizontal position where the footrest surface is upward, and thus the first footrest element is stretched more flexibly and quickly.

[0143] Specifically, in the example, the first connecting rod 31, the second connecting rod 32, the third connecting rod 33, the fourth connecting rod 34, the first footrest element 35, the coupling rod 36, the second footrest element 37 and the footrest connection element 38 are all pivotally connected or hinged; and all parts may be connected by means of a rotary shaft, a shaft pin, a rivet, a bolt, a nut and a combination thereof or other fasteners capable of implementing the pivotal connection.

[0144] Optionally, in the example, when the footrest extension mechanism is retracted to the limit position, the first footrest element 35 is located above the second footrest element 37, and the footrest surface of the first footrest element 35 and the footrest surface of the second footrest element 37 may be in the same vertical plane. When the footrest extension mechanism is stretched to a limit position from a retracted position, the footrest surface of each of the first footrest element 35 and the second footrest element 37 rotates upward, and the first footrest element 35 and the second footrest element 37 are spaced apart from one another.

[0145] Specifically, as shown in FIG. 8, the footrest extension mechanism further includes a footrest plate component 39, where the footrest plate component 39 includes a first footrest plate 391 and a second footrest plate 392, the first footrest plate 391 is connected to the first footrest element 35, and the second footrest plate 392 is connected to the second footrest element 37. Specifically, a footrest surface bending inward is respectively provided on the first footrest element and the second footrest element, and the footrest surface is fixedly connected to the footrest plate, namely the first footrest plate and the second footrest plate are respectively fixed on the corresponding footrest surface.

[0146] In the example, as shown in FIG. 8 and FIG. 9, the linkage support 1 of the seat drives the first connecting rod 31 and the third connecting rod 33 to rotate, such that the footrest extension mechanism moves from the retracted position shown in FIG. 8 to the stretched position shown in FIG. 9, and at the stretched position, the footrest surface of each of the first footrest element 35 and the second footrest element 37 is horizontal. When the footrest extension mechanism is stretched from the retracted position to the limit position, the second connecting rod 32 drives the first footrest element 35 to rotate upward and the coupling rod 36 rotates with the first footrest element 35, such that while the first footrest element 35 rotates more flexibly, the first footrest element 35 is supported; and the fourth connecting rod 34 drives the second footrest element 37 and the footrest connection element 38 to extend forward and rotate upward, until the second footrest element 37 is stretched to the limit position. When the footrest extension mechanism is retracted from the stretched position to the limit position, movement directions of components in the footrest extension mechanism are reversed to those in the stretching process.

[0147] In some examples, when the footrest extension mechanism is stretched to the limit position, a distance between the first footrest element and the second footrest element is greater than 140 mm, and may be preferably 145 mm, 147 mm, 150 mm, or 155 mm, namely the spacing distance after the first footrest element and the second footrest element are stretched is increased.

[0148] In the footrest extension mechanism of the present disclosure, the first footrest element is hinged to the fourth connecting rod by means of the coupling rod, such that the first footrest element and the second footrest element can be drawn close and separated apart more flexibly; when the footrest extension mechanism is retracted, the two footrest elements are retracted and drawn close, with a small space occupation; and when the footrest extension mechanism is stretched, the stretched length of the footrest extension mechanism is increased to better support legs and feet, improve the comfort of the seat and meet use requirements of users at different heights.

[0149] An example further provides a seat stretching device as shown in FIGS. 8-11, including: a leg stretching device 3 constructed as a footrest extension mechanism, a linkage support 1, and a back mechanism 2, where one end of the linkage support 1 is connected to the back mechanism 2, the other end of the linkage support 1 is connected to the footrest extension mechanism, and the footrest extension mechanism is connected to a footrest plate component 39.

[0150] Specifically, the linkage support 1 includes a support structure 12 and a linkage structure 13, the support structure 12 including a base 121, a first support element 122, a second support element 123, and a base coupling component 124, where one end of the base 121 is connected to the first support element 122, the other end of the base 121 is connected to the second support element 123, and the base coupling component 124 is provided between the first support element 122 and the second support element 123. Specifically, the base coupling component 124 includes: a seat coupling element 1242 and a back coupling element 1241, one end of the seat coupling element 1242 is connected to the first support element 122, and the other end of the seat coupling element 1242 is connected to the back coupling element 1241.

[0151] Specifically, the linkage structure 13 includes: a lateral plate 131, a first coupling element 132, a second coupling element 133 and a third coupling element 134, a middle of the second coupling element 133 is rotatably connected to the lateral plate 131, one end of the second coupling element 133 is connected to one end of the first coupling element 132, the other end of the first coupling element 132 is connected to the first support element 122, the other end of the second coupling element 133 is connected to one end of the third coupling element 134, and the other end of the third coupling element 134 is pivotally connected to the footrest extension mechanism.

[0152] Specifically, the linkage support 1 further includes a transmission structure 14, the transmission structure 14 includes a first transmissive element 141 and a second transmissive element 142 that are connected to one another, the first transmissive element is connected to a driving device, the second transmissive element is connected to the footrest extension mechanism, and the driving device drives a movement of the linkage support by means of the transmission structure. In some examples, the driving device may be a manual driving device; and in other examples, the driving device may be a motor driving device, and the motor driving device may be a push rod motor or slider motor driving device.

[0153] Specifically, in the example, the back mechanism 2 is connected to the lateral plate 131 of the linkage structure 13; and the movement of the linkage support 1 drives the back mechanism 2 and the footrest extension mechanism for stretching or retracting.

[0154] In the example, the footrest extension mechanism and the back mechanism can also be continuously adjusted; when only the footrest extension mechanism is stretched, the corresponding seat is in the relaxing state; when both the footrest extension mechanism and the back mechanism are stretched to the limit position, the corresponding seat is in the lying state; and when both the footrest extension mechanism and the back mechanism are retracted to the limit position, the corresponding seat is in the sitting state.

[0155] The footrest extension mechanism and the seat stretching device are provided in the example. The footrest extension mechanism is stretched and retracted more flexibly and has a greater stretched length by adjusting the structure of the footrest extension mechanism, thereby better supporting legs and feet, improving the comfort of the seat, and meeting use requirements of users at different heights.

[0156] There are two mechanical stretching devices in the above examples of the present disclosure; and the two mechanical stretching devices are spaced apart and arranged symmetrically based on a central surface of the base. With a seat frame respectively provided on the mechanical stretching devices, the mechanical stretching devices are packaged into the finished sofa.

[0157] The present disclosure is to provide a seat unit with a simpler structure and a better ergonomic adaptation.

[0158] The present disclosure provides a mechanical stretching device for a movable seat unit. The mechanical stretching device includes left and right parts in a mirror symmetry; and hereinafter, descriptions are made to one part.

[0159] The mechanical stretching device according to the present disclosure includes: [0160] a linkage support, including a support structure for supporting a mechanical stretching device on ground and a linkage structure attachable to a seating portion of a seat unit; [0161] a back mechanism, the back mechanism being pivotally connected to the linkage support and being used for attaching to a backrest of the seat unit; and optionally, the back mechanism including a backrest connection element attached to the backrest and a back connecting rod pivotally connected to the backrest connection element; and [0162] a leg stretching structure provided with a footrest element, the leg stretching structure being pivotally connected to the linkage support and the footrest element being attached to a footrest of the seat unit.

[0163] According to the present disclosure, the mechanical stretching device can implement a sequential conversion or a reverse sequential conversion from a sitting state to a relaxing state and then to a lying state; in the sitting state, the footrest element may be folded below the seating portion; in the relaxing state, the footrest element may be stretched to be in front of the seating portion and inclined relative to a horizontal direction; and in the lying state, an angle between the backrest element and the seating portion may be increased relative to that in the relaxing state, and the footrest element may extend further forward and upward than in the relaxing state, such that a height of a highest point of the leg stretching structure relative to a horizontal plane is greater than that of a highest point of the back mechanism relative to the horizontal plane, thereby forming a so-called zero gravity position; and at the zero gravity position, a user of the seat unit may have a leg obviously higher than a head and at least higher than a chest.

[0164] According to the present disclosure, an angle formed between an extension direction of the footrest element in the lying state and the horizontal direction may be in a range between 9 and 23, preferably between 14 and 21, and more preferably between 18 and 19; an included angle between the extension direction of the footrest element in the relaxing state and the horizontal direction may be less than the included angle between the extension direction of the footrest element in the lying state and the horizontal direction; and optionally, in the relaxing state, the angle formed between the extension direction of the footrest element and the horizontal direction may be in a range between 8 and 20, preferably between 12 and 19, and more preferably between 14 and 15.

[0165] According to the present disclosure, in the lying state, an angle formed between the seating portion and the horizontal direction may be in a range between 8 and 17, and preferably between 13 and 16. In the technical solution, reducing the included angle between the seating portion in the lying state and the horizontal direction appropriately will make the user more comfortable in the lying state.

[0166] Optionally, in the lying state, a height difference between the highest point of the leg stretching structure and the highest point of the back mechanism may be in a range between 200 mm and 400 mm, and is preferably 265 mm.

[0167] According to the present disclosure, the support structure may include a base, a first support element, a second support element, and a base coupling component, where the first support element and the second support element are pivotally connected to the base respectively, and the base coupling component is provided between the first support element and the second support element.

[0168] According to the present disclosure, the linkage structure may include a lateral plate for attaching to the seating portion of the seat unit; the linkage structure may further include a first coupling element, a second coupling element and a third coupling element, a middle of the second coupling element may be rotatably connected to the lateral plate, one end of the second coupling element may be connected to one end of the first coupling element, the other end of the first coupling element may be connected to the first support element, the other end of the second coupling element may be connected to one end of the third coupling element, and the other end of the third coupling element may be connected to a footrest extension mechanism.

[0169] According to the present disclosure, the base coupling component may include a back coupling element and a seat coupling element; optionally, the back coupling element may be provided with multiple pivotal points; and the back coupling element may be respectively hinged to the back mechanism and optionally a back connecting rod of the back mechanism, the linkage structure and optionally the lateral plate of the linkage structure, the seat coupling element and the second support element by means of different pivotal points.

[0170] In the technical solution according to the present disclosure, a maximum allowable displacement moved forward by the linkage support is changed by adjusting a hinge point between the back connecting rod and the backrest connection element as well as a hinge point between the first support element and the base and the back coupling element, such that the degree at which the lateral plate is raised upward in the lying state is reduced, and the angle between the lateral plate and the horizontal direction is reduced, thereby improving the comfort of the user.

[0171] The mechanical stretching device according to the present disclosure may further include the leg stretching structure, and the leg stretching structure may include a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod and a first footrest element, where a rear end of the first connecting rod is hinged to the linkage structure, a front end of the first connecting rod is hinged to a rear end of the second connecting rod, a rear end of the third connecting rod is hinged to the linkage structure, a front end of the third connecting rod is hinged to a rear end of the fourth connecting rod, a front end of each of the second connecting rod and the fourth connecting rod is hinged to the first footrest element, a middle of the second connecting rod is further hinged to a middle of the third connecting rod, and optionally, an end of the second connecting rod close to the first connecting rod is provided with a first connecting point, and the second connecting rod is hinged to the middle of the third connecting rod at the first connecting point.

[0172] Some examples of the present disclosure provide a mechanical stretching device for a movable seat unit, the mechanical stretching device includes: a linkage support that comprises a support structure configured to support the mechanical stretching device on ground and a linkage structure attachable to a seating portion of the seat unit; a back mechanism that is pivotally connected to the linkage support and is configured to attach to a backrest of the seat unit; and a leg stretching structure including a footrest element, and the leg stretching structure is pivotally connected to the linkage support, and the footrest element is attached to a footrest of the seat unit. The mechanical stretching device is configured to implement a sequential conversion or a reverse sequential conversion of the seat unit from a sitting state to a relaxing state and to a lying state. in the sitting state, the footrest element is folded below the seating portion; in the relaxing state, the footrest element is stretched to be in front of the seating portion and inclined relatively to a horizontal direction; and in the lying state, an angle between the backrest and the seating portion is increased compared to the angle between the backrest and the seating portion in the relaxing state, and the footrest element extends forward and upward from a position of the footrest element in the relaxing state, such that a height of a highest point of the leg stretching structure is greater than a height of a highest point of the back mechanism; and in the lying state, an angle between an extension direction of the footrest element and the horizontal direction is in a range between 9 and 23.

[0173] In another example of the present disclosure, a movable seat unit is provided. The movable seat unit includes: a seating portion, a backrest, a footrest, a motor driving device, and a mechanical stretching device as described above.

[0174] Some other examples of the present disclosure provides a mechanical stretching device for a movable seat unit, the mechanical stretching device includes: a linkage support that comprises a support structure configured to support the mechanical stretching device on ground and a linkage structure attachable to a seating portion of the seat unit; a back mechanism that is pivotally connected to the linkage support and is configured to attach to a backrest of the seat unit; and a leg stretching structure including a footrest element, and the leg stretching structure is pivotally connected to the linkage support, and the footrest element is attached to a footrest of the seat unit. The mechanical stretching device is configured to implement a sequential conversion or a reverse sequential conversion of the seat unit from a sitting state to a relaxing state and to a lying state. in the sitting state, the footrest element is folded below the seating portion; in the relaxing state, the footrest element is stretched to be in front of the seating portion and inclined relatively to a horizontal direction; and in the lying state, an angle between the backrest and the seating portion is increased compared to the angle between the backrest and the seating portion in the relaxing state, and the footrest element extends forward and upward from a position of the footrest element in the relaxing state, such that a height of a highest point of the leg stretching structure is greater than a height of a highest point of the back mechanism. In the lying state, a height difference between the highest point of the leg stretching structure and the highest point of the back mechanism is in a range between 200 mm and 400 mm; and in the lying state, an angle between an extension direction of the footrest element and the horizontal direction is in a range between 9 and 23.

[0175] Some other examples of the present disclosure provide a mechanical stretching device for a movable seat unit, the mechanical stretching device includes: a linkage support that comprises a support structure configured to support the mechanical stretching device on ground and a linkage structure attachable to a seating portion of the seat unit; a back mechanism that is pivotally connected to the linkage support and is configured to attach to a backrest of the seat unit; and a leg stretching structure including a footrest element, and the leg stretching structure is pivotally connected to the linkage support, and the footrest element is attached to a footrest of the seat unit. The mechanical stretching device is configured to implement a sequential conversion or a reverse sequential conversion of the seat unit from a sitting state to a relaxing state and to a lying state. in the sitting state, the footrest element is folded below the seating portion; in the relaxing state, the footrest element is stretched to be in front of the seating portion and inclined relatively to a horizontal direction; and in the lying state, an angle between the backrest and the seating portion is increased compared to the angle between the backrest and the seating portion in the relaxing state, and the footrest element extends forward and upward from a position of the footrest element in the relaxing state, such that a height of a highest point of the leg stretching structure is greater than a height of a highest point of the back mechanism. In the lying state, a height difference between the highest point of the leg stretching structure and the highest point of the back mechanism is in a range between 200 mm and 400 mm.

[0176] The seat device according to the prior art has the following defects: When the seat is stretched, the footrest mechanism easily rubs the ground to affect the use of the user; and the footrest mechanism of the seat only rotates simply and has a short stretched length overall, such that legs and feet cannot be completely supported in the relaxing state and the lying state to affect the comfort of the seat.

[0177] The existing mechanical stretching device provided with the extended footrest plate employs the conventional chute structure; the chute structure is prone to generate noise in use; and the chute structure has the poor structural stability because it is easily worn after repeated use to make the leg structure stretched or retracted unsuccessfully.

[0178] In view of the above technical problems, the present disclosure further provides an alternative solution for the leg stretching structure and the seat stretching device. In the alternative solution, the leg stretching structure is constructed as a footrest extension mechanism, including: a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a first footrest element, a coupling rod, a second footrest element, and a footrest connection element, where: [0179] the second connecting rod includes one end hinged to the first footrest element, and the other end hinged to the first connecting rod, the first connecting rod is hinged to the linkage support of the seat unit, the fourth connecting rod includes one end hinged to the second footrest element, and the other end hinged to the third connecting rod, the first footrest element is hinged to one end of the coupling rod, and the other end of the coupling rod is hinged to a middle of the fourth connecting rod; and [0180] the footrest connection element includes a first connection element and a second connection element, the first connection element includes one end hinged to a middle of the second footrest element, and the other end hinged to one end of the second connection element, the other end of the second connection element is hinged to the middle of the second connecting rod, and a middle of the second connection element is hinged to the middle of the fourth connecting rod.

[0181] Further, the middle of the second footrest element may be provided with a first limit element, and when the first limit element abuts against the second connection element, the second footrest element may be retracted to a limit position to prevent the footrest element from being loose.

[0182] Further, an end of the second connecting rod close to the first connecting rod may be provided with a first connecting point, the second connecting rod may be hinged to a middle of the third connecting rod at the first connecting point, and the third connecting rod may be connected to the linkage support.

[0183] Further, an end of the second connecting rod close to the first footrest element may be provided with a second connecting point, and the second connecting rod may be connected to the second connection element at the second connecting point.

[0184] Further, an end of the fourth connecting rod close to the second footrest element may be sequentially provided with a footrest connecting point, a coupling rod connecting point and a connection element connecting point; and [0185] the fourth connecting rod may be connected to the second footrest element at the footrest connecting point, the fourth connecting rod may be connected to the coupling rod at the coupling rod connecting point, the fourth connecting rod may be connected to the second connection element at the connection element connecting point, and the coupling rod connecting point may be provided between the footrest connecting point and the connection element connecting point.

[0186] Further, a second connecting rod connecting point and a linkage point may be arranged on the first footrest element, and a distance from the linkage point to the coupling rod connecting point may be greater than that from the linkage point to the second connecting rod connecting point.

[0187] Further, when the footrest extension mechanism is retracted to the limit position, the first footrest element may be located above the second footrest element, and a footrest surface of the first footrest element and a footrest surface of the second footrest element may be in the same vertical plane.

[0188] Further, when the footrest extension mechanism is stretched to a limit position from a retracted position, the footrest surface of each of the first footrest element and the second footrest element may rotate upward, and the first footrest element and the second footrest element may be spaced apart from one another.

[0189] Further, the footrest extension mechanism may further include a footrest plate component, where the footrest plate component includes a first footrest plate and a second footrest plate, the first footrest plate is connected to the first footrest element, and the second footrest plate is connected to the second footrest element.

[0190] According to the alternative solution, the stretched length of the footrest plate of the seat can be increased by adjusting the structure of the footrest extension mechanism of the seat, thereby better supporting legs and feet of the user and improving the comfort of the seat.

[0191] According to the present disclosure, the linkage support may include a transmission structure for connecting a driving device to the leg stretching structure.

[0192] According to the alternative solution, the present disclosure further provides the corresponding seat stretching device, including the footrest extension mechanism, a linkage support, and a back mechanism, where: [0193] one end of the linkage support is connected to the back mechanism, the other end of the linkage support is connected to the footrest extension mechanism, and the footrest extension mechanism is connected to the footrest plate component.

[0194] According to the present disclosure, the transmission structure may optionally include a first transmissive element and a second transmissive element that are connected to one another, the first transmissive element may be connected to the driving device, and the second transmissive element may be connected to the leg stretching structure.

[0195] The driving device may be optionally a manual driving device or a motor driving device, and may optionally include a linear motor.

[0196] With the foregoing technical solution, the present disclosure achieves the following beneficial effects.

[0197] In the footrest extension mechanism of the present disclosure, the first footrest element is hinged to the fourth connecting rod by means of the coupling rod, such that the first footrest element and the second footrest element can be drawn close and separated apart more flexibly; when the footrest extension mechanism is retracted, the two footrest elements are retracted and drawn close, with a small space occupation; and when the footrest extension mechanism is stretched, the stretched length of the footrest extension mechanism is increased to better support legs and feet, improve the comfort of the seat and meet use requirements of users at different heights.

[0198] Alternatively, the present disclosure further relates to a footrest extending structure and a stretching support, with corresponding technical solutions referring to the Chinese patent application CN 208625029 U; and contents disclosed in the patent literature should be completely included in the present disclosure.

[0199] On the other hand, the present disclosure further relates to a seat unit, including the mechanical stretching device, as well as a seating portion, a backrest, and a footrest attached to the mechanical stretching device, and optionally including a motor driving device.

[0200] FIG. 12 schematically illustrates a perspective view of a movable seat according to one or more examples of the present disclosure.

[0201] The seat (also called seat unit) includes a mechanical stretching device and an attached frame assembly. The frame assembly includes a seat frame 50, armrest frames 51 fixedly connected to both sides of the seat frame 50, and a backrest frame 52 that can move relative to the seat frame 50. The seat frame 50 is generally designed as a rectangular cross-section frame to support the seating portion 500 shown in FIGS. 16 to 18. In some examples, this seating portion is made with elastic properties, such as a well-padded cushion. The backrest frame 52 may be constructed as two mirror-symmetrical plate-like members, as shown in FIG. 12. In other examples not shown, the backrest frame 52 may be formed as a single plate-like member extending between the two armrest frames 51. The backrest frames 52 support the backrest 520 shown in FIGS. 16 to 18. In some examples, the backrest 520 may be made with elastic properties, such as a well-padded cushion.

[0202] The mechanical stretching device shown in FIG. 13 includes a seat portion assembly 1, a backrest assembly 2, and a leg stretching device 3. The seat portion assembly 1is also called the linkage support as shown in FIG. 1. The backrest assembly 2 is hinged to the rear part of the seat portion assembly 1, and the leg stretching device 3 is hinged to the front part of the seat portion assembly 1. The backrest assembly 2 is also called the back mechanism as shown in FIG. 1. The seat portion assembly 1 is attached to the seat portion 520 of the seat unit, the backrest assembly 2 is attached to the backrest 520 of the seat unit, and the leg stretching device 3 is attached to a footrest (not shown) of the seat unit.

[0203] By the coordinated movement of the seat portion assembly 1, backrest assembly 2, and leg stretching device 3, the seat unit or its mechanical stretching device, can shift between the sitting position (also called sitting state above), the TV-viewing position (also called relaxing state above), and/or the lying position (also called lying state above). In the sitting position, the backrest 520 stays upright, and the footrest is tucked beneath the seat portion 500. In the TV-viewing position, the backrest 520 remains mostly upright without noticeable recline, while the footrest extends along with the leg stretching device 3, moving upward and forward to the front of the seat portion 500. In the lying position, the footrest stays fully extended in front of the seat portion 500, and the backrest 520 reclines considerably backward.

[0204] The seat portion assembly 1 includes a base assembly 11, a front swing rod 1112, a rear swing rod 1113, and a side plate 140. The side plate 140 is the lateral plate 131 as shown in FIGS. 3-5.

[0205] In the example shown in FIG. 12, the mechanical stretching device is used for a metal frame floor-standing seat unit. The base assembly 11 directly supports the mechanical stretching device on the floor surface and includes two laterally symmetrical lateral rails 111 arranged on the left and right sides, as well as a front transverse rail 112 and a rear transverse rail 113 that connect the two lateral rails 111. However, in an unillustrated example, the base assembly 11 may also indirectly support the mechanical stretching device above the floor surface. For example, the base assembly 11 may be rotatably mounted on a rotary base, or the base assembly 11 may be fixedly coupled to the armrest portion of an armrest floor-standing seat unit. The lateral rails 111 may be the same as the lateral rails 1211 as shown in FIG. 2, the front transverse rail 112 may be the same as the front transverse rail 1212 and the rear transverse rail 113 may be the same as the rear transverse rail 1213 as shown in FIG. 2.

[0206] The front swing rod 112 is hinged at its lower end to the front end of the lateral rail 111, and the rear swing link 113 is hinged at its lower end to the rear end of the lateral rail 111.

[0207] The side plate 140 includes a front support section 140a and a rear support section 140b at its upper part. These sections are configured as horizontally bent segments of the side plate 140, either inward or outward, and are used to support the auxiliary seat frame 50a, where the seat frame 50 is fixedly connected to the auxiliary seat frame 50a.

[0208] The side plate 140 is capable of moving relative to the base assembly 11, as well as relative to the ground. To achieve this, the mechanical stretching device particularly includes a central coupling element 15, a seat coupling element 16, and a side plate coupling element 17, as shown in FIGS. 14 and 15. The seat coupling element 16 may be the same as the seat coupling element 1242 shown in FIG. 4. The side plate coupling element 17 may be the same as the back coupling element 1241 shown in FIG. 4.

[0209] The central coupling element 15 is equipped with multiple pivot points. At these pivot points, the central coupling element 15 is hinged to the backrest assembly 2, the side plate 140, the seat coupling element 16, and the rear swing link 13. One end of the seat portion coupling element 16 is hinged to the front swing link 12 via the side plate coupling element 17, while the other end is hinged to the central coupling element 15. As a result, the swinging of the front swing link 12 and the rear swing rod 1113 drive the movement of the side plate 140 relative to the base assembly 11, which in turn drives the movement of the backrest assembly 2.

[0210] The backrest assembly 2 includes a backrest mounting member 20 attached to the backrest 520 and a backrest connecting rod assembly 220 pivotally connected to the backrest mounting member 20. The backrest mounting member 20 is fixedly connected to the lower section of the backrest frame 52, and the backrest 520 is securely supported on the backrest frame 52. The backrest connecting rod assembly 220 includes a first backrest connecting rod 221, a second backrest connecting rod 212, and a third backrest connecting rod 223. The upper end of the first backrest connecting rod 221 is hinged to the front end of the backrest mounting member 20 at a first pivot point P1. The front end of the second backrest connecting rod 222 is hinged to the side plate 140 at a second pivot point P2. The rear end of the second backrest connecting rod 222 is hinged to the lower end of the third backrest connecting rod 223, and the middle portion of the second backrest connecting rod 222 is hinged to the first backrest connecting rod 221. The upper end of the third backrest connecting rod 223 is hinged to the rear end of the backrest mounting member 20. The lower end of the first backrest connecting rod 221 is hinged to the central coupling element 15 at a third pivot point P3.

[0211] As shown particularly in FIG. 17, the leg stretching device 3 includes multiple link rods pivotally connected to each other. The rear end of the first connecting rod 31 is hinged to the side plate 140, and the front end of the first connecting rod 31 is hinged to the rear end of the second connecting rod 32. The rear end of the third connecting rod 33 is hinged to the front end of the side plate 140, and the front end of the third connecting rod 33 is hinged to the rear end of the fourth connecting rod 34. The front ends of the second connecting rod 32 and the fourth connecting rod 34 are respectively hinged to the first footrest element 35.

[0212] Additionally, the mechanical stretching device further includes a first transmissive element 18 and a second transmissive element 19 pivotally connected to each other. The first transmissive element 18 and the second transmissive element 19 may be respectively the first transmissive element 141 in FIG. 11 and the second transmissive element 142 in FIG. 5. One end of the first transmissive element 18 is hinged to one end of the second transmissive element 19, while the other end of the first transmissive element 18 is hinged to the side plate 140. The other end of the second transmissive element 19 is hinged to the leg stretching device 3, particularly to the first connecting rod 31. As a result, when the side plate 140 of the seat portion assembly 1 moves relative to the base assembly 11, it drives the contraction and extension movement of the leg stretching device 3.

[0213] To enable the seat unit to transition between different positions, an electric driving device 4 is also provided. The electric driving device 4 includes a motor crossbar 40 fixedly connected on its inner side, and the electric driving device 4 is coupled between the motor crossbar 40 and the front transverse rail 112 of the base assembly 11. In some examples, the electric driving device 4 is designed as a linear electric actuator. Through the telescoping movement of the linear electric actuator, the side plate 140 can move relative to the base assembly 11, thereby driving the movement of the backrest assembly 2 and the leg stretching device 3. This enables the seat unit to switch between different positions, such as the sitting position, TV-viewing position, and/or lying position.

[0214] In this example, the electric driving device 4 is configured to facilitate the mechanical stretching device of the seat unit to transition between the sitting position, TV-viewing position, and lying position. The electric driving device 4 includes a motor head 41, a motor slide rail 42 fixedly connected to the motor head 41, a motor slider 43 that can slide along the motor slide rail 42 relative to the motor head 41, and a motor connecting rod 44. The motor head 41 is fixedly installed on the front transverse rail 112. One end of the motor connecting rod 44 is hinged to the motor slider 43, and the other end is hinged to the motor crossbar 40.

[0215] The mechanical stretching device further includes a first coupling element 132, a second coupling element 133, and a third coupling element 134. The middle portion of the second coupling element 133 is rotatably connected to the side plate 140. One end of the second coupling element 133 is connected to one end of the first coupling element 132, while the other end of the first coupling element 132 is connected to the front swing rod 1112. The other end of the second coupling element 133 is connected to one end of the third coupling element 134, and the other end of the third coupling element 134 is pivotally connected to the first connecting rod 31 of the leg stretching device 3.

[0216] FIGS. 16 to 18 schematically illustrate side views of the seat unit in the sitting position, TV-viewing position, and lying position. For clarity, the seat frame and one side armrest frame of the seat unit's frame assembly are omitted.

[0217] FIGS. 19 to 21 also schematically illustrate side views of the seat unit in the sitting position, TV-viewing position, and lying position. Similarly, for clarity, one side armrest frame, the seat portion, and the backrest of the seat unit's frame assembly are omitted.

[0218] When the mechanical stretching device is in the sitting position shown in FIG. 16 or FIG. 19, the backrest mounting member 20 of the backrest assembly 2 and the backrest 520 stand upright, and the leg stretching device 3 is retracted beneath the seat portion 500.

[0219] During the transition of the mechanical stretching device from the sitting position shown in FIG. 16 or FIG. 19 to the TV-viewing position shown in FIG. 17 or FIG. 20, the electric driving device 4 operates, causing the motor slider 43 to slide along the motor slide rail 42 toward the motor head 41, thereby reducing the distance between the motor head 41 and the motor slider 43. In this process, the motor slider 43 moves the side plate 140 forwardi.e., in the direction of the leg stretching device 3via the motor connecting rod 44, causing the front swing rod 1112 and the rear swing rod 1113 to swing forward. Consequently, the first coupling element 132 moves forward with the front swing rod 1112 and pushes the first connecting rod 31 through the second coupling element 133 and third coupling element 134, thereby extending the leg stretching device 3. The side plate coupling element 17 and seat coupling element 16 also move forward with the front swing rod 1112, driving the central coupling member 15 forward. During this process, the central coupling element 15 moves forward together with the side plate 140, which in turn moves the backrest assembly 2 forward and downward through the first backrest connecting rod 221 and second backrest connecting rod 222, while the backrest mounting member 20 does not noticeably tilt. Notably, the first pivot point Pl and second pivot point P2 both move downward and forward.

[0220] During the transition of the mechanical stretching device from the TV-viewing position shown in FIG. 17 or FIG. 20 to the lying position shown in FIG. 18 or FIG. 21, the electric driving device 4 continues to operate, causing the motor slider 43 to further slide along the motor rail 42 toward the motor head 41, further reducing the distance between the motor head 41 and the motor slider 43. In this process, the motor slider 43 continues to move the side plate 140 forwardi.e., toward the leg stretching device 3via the motor connecting rod 44, and the front swing rod 1112 and rear swing rod 1113 swing forward with a greater amplitude. When the front swing rod 1112 and the rear swing rod 1113 reach their maximum swing, the side plate 140 moves significantly forward relative to the central coupling element 15, increasing the distance between the third pivot point P3located between the central coupling element 15 and the first backrest connecting rod 221and the second pivot point P2located between the side plate 140 and the second backrest connecting rod 222. As a result, while moving forward, the backrest connecting rod assembly 220 compresses itself, and the backrest mounting member 20 rotates sharply backward at or about the first pivot point P1. In this process, not only do the first pivot point P1 and the second pivot point P2 both move forward, but the distance between the first pivot point PI and the second pivot point P2 also noticeably decreases compared to their spacing in the sitting and TV-viewing positions.

[0221] The backrest frame 52 may have various shapes as needed. For example, in the embodiment shown in FIGS. 19 to 20, the backrest frame 52 includes a lower frame section 52a and an upper frame section 52b. The lower frame section 52a is configured for fixed connection to the backrest mounting member 20, while the upper frame section 52b transitions to the lower frame section 52a via a stepped portion. The stepped section includes a lower edge that extends in a substantially arcuate shape, as illustrated in the side views of FIGS. 19 and 20. Correspondingly, the rear part of the armrest frame 51 also has a curved extending section, forming a gap between the armrest frame 51 and the upper frame section 52b. During the transition from the sitting/TV-viewing position to the lying position, the backrest assembly 2 moves forward along with the side plate 140, and the gap between the armrest frame 51 and the upper frame section 52b remains substantially unchanged. Further, during the transition, a gap between the lower frame section 52a and the seat frame 50 also remains substantially unchanged. This arrangement allows the attachment of a so-called T-shaped backrest to the backrest frame 52. This design not only improves user comfort but also significantly enhances the aesthetics of the seat unit.

[0222] FIGS. 22-30 illustrate side views of a movable seat unit according to other examples of the present disclosure. In these examples, the leg stretching device 3 is in the same manner as the leg stretching device 3 as shown in FIGS. 9-11, in the meanwhile, the backrest frames 52 and the backrest assembly are respectively in the same manner as the backrest frames 52 and the backrest assembly 2 as shown in FIGS. 12-21. Further, FIGS. 31-36 respectively show the positional changes of different positions (sitting, TV-viewing, and lying positions) corresponding to the movable seat in FIGS. 22-27. In these different positions, the backrest frame 52 remains in contact with the wall, thus achieving a true zero wall configuration.

[0223] According to the present disclosure, the backrest mounting member is coupled to the seat portion assembly through a backrest connecting rod assembly. Through the scissor structure of the backrest connecting rod assembly, as the backrest mounting member rotates rearward, the backrest connecting rod assembly itself compresses and, as a whole, moves forward relative to the ground toward the front of the seat. This coordinated motion reduces or even eliminates the gap that typically forms between the backrest and the seat portion during posture transitions. As a result, the design achieves the true zero wall configuration, saving installation space and minimizing the risk of items falling through the gap. It also prevents the user's upper garment from being pulled upward, ensuring a more comfortable and seamless zero back-pull experience.

[0224] In some examples, in the lying position, a highest point of the first footrest element is higher than a highest point of the backrest mounting member. This configuration achieves a zero gravity posture, enhancing user comfort.

[0225] The present disclosure may include dedicated hardware implementations such as application specific integrated circuits and other hardware devices. The hardware implementations can be constructed to implement one or more of the methods described herein. Examples that may include the apparatus and systems of various implementations can broadly include a variety of mechanical systems. One or more examples described herein may implement functions using two or more specific interconnected hardware devices or units with related control and data signals that can be communicated between and through the units, or as portions of the device. Accordingly, the apparatus or system disclosed may encompass software and hardware implementations. The terms circuit, sub-circuit, unit, or sub-unit may include memory (shared, dedicated, or group) that stores code or instructions that can be executed. The unit or circuit may include one or more components that are connected.

[0226] The above examples of the present disclosure focus on the differences among various examples, and the different optimization features among the various examples can be combined to form a better example as long as they are not contradictory, which will not be detailed here for brevity concern.

[0227] The above-described are only examples of the present disclosure, and are not used to limit the present disclosure. For those skilled in the art, various modifications and variations are possible. Any modification, equivalent substitution, improvement, and others made within the spirit and principle of the present disclosure shall be included within the scope the present disclosure.