CN113509017B

CN113509017B - Mechanical stretching device for a movable seat unit and seat unit

Info

Publication number: CN113509017B
Application number: CN202110651109.1A
Authority: CN
Inventors: 李晓鸿; 刘伟; 宋刚; 李元坤
Original assignee: Remacro Machinery and Technology Wujiang Co Ltd
Current assignee: Ruimai Technology Co ltd
Priority date: 2021-06-10
Filing date: 2021-06-10
Publication date: 2023-11-07
Anticipated expiration: 2041-06-10
Also published as: CN113509017A

Abstract

The invention relates to a mechanical stretching device for a movable seating unit, comprising: -a tilting mechanism (2) comprising a multi-bar mechanism and for attachment to a seat portion, a backrest and a footrest of the seat unit, configured to enable a change of the seat unit between two end positions, namely a sitting position in which the footrest is folded under the seat portion, and a lying position; in the recumbent position, the backrest is reclined and the footrest is extended forward to the front of the seat portion; wherein the tilting mechanism (2) is configured such that the seat unit is shifted between a sitting position and a lying position by an electric actuating unit (4), wherein when the seat unit is shifted from the sitting position to the lying position, the footrest is extended forward to the front of the seat portion while the backrest is tilted backward, and when the seat unit is shifted from the lying position to the sitting position, the footrest is retracted backward to the rear under the seat portion while the backrest is tilted forward.

Description

Mechanical stretching device for a movable seat unit and seat unit

Technical Field

The present invention relates to a mechanical stretcher for a movable seating unit and a seating unit including the mechanical stretcher.

Background

A variety of seating units for movable seating units, such as rocking chairs, sofas with rocking function, are known in the prior art. The seating unit typically has a base, a back rest support, a seat support, a tilt mechanism, and is capable of changing between several different attitudes. However, the known seating units often do not meet the comfort requirements of the user, for example, the user has to take a laborious manual effort to perform the above-mentioned posture change, or too many postures are preset, so that the user has to undergo a long change process in order to finally obtain the desired seating posture. Obviously, this also results in a more complex structure of the seating unit, with a higher risk of failure and higher manufacturing and maintenance costs.

Disclosure of Invention

The invention aims to solve the technical problem of providing a seat unit which is simpler in structure, simpler and more convenient to operate and lower in manufacturing cost.

To solve the above technical problem, the present invention provides a mechanical stretching device for a movable seat unit, comprising a tilting mechanism comprising a multi-link mechanism and for attachment to a seat portion, a backrest and a footrest of the seat unit, configured to enable a transition of the seat unit between two end positions, namely a sitting position in which the footrest is folded under the seat portion and a lying position; in the recumbent position, the backrest is reclined and the footrest extends forward to the front of the seat portion.

According to the invention, the reclining mechanism is configured such that the seat unit is shifted between the sitting position and the lying position by the electric actuating unit, wherein when the seat unit is shifted from the sitting position to the lying position, the footrest is extended forward to the front of the seat portion while the backrest is reclined backward, and when the seat unit is shifted from the lying position to the sitting position, the footrest is retracted backward under the seat portion while the backrest is retracted forward to the recline.

The invention is based on the idea that the movable seating unit is only changed between two end positions, namely between a sitting position and a lying position, which are most common for the user, and that the position change of the backrest is performed simultaneously with the position change of the footrests. This eliminates, on the one hand, the unusual seat posture, which makes the design structure concerned simpler and cheaper to manufacture, and, on the other hand, the user is thereby able to obtain his desired seat posture in the most convenient way. Furthermore, the two end positions are shifted by the electric actuating unit, whereby the user can operate the seat unit in a labor-saving manner.

In a preferred embodiment, the tilting mechanism comprises a leg extension unit for mounting a footrest, a seat support for mounting a seat part and a backrest support for mounting a backrest, which are connected in series in a pivotable manner.

In a preferred embodiment, the mechanical stretching device comprises a support assembly for direct or indirect support on the ground, preferably for providing a rocking or swinging function for the seat unit.

In a preferred embodiment, the tilting mechanism is configured for a pendulum or swing-type seat unit, which allows the seat unit to pivot or swing back and forth relative to the floor in the sitting position, and does not allow the seat unit to pivot or swing back and forth relative to the floor in the lying position. To achieve this, the tilting mechanism comprises a swing limit mechanism which is designed to allow the seat support and the backrest support of the tilting mechanism to swing back and forth relative to the base of the seat unit in the sitting position and to prevent the seat support from swinging back and forth relative to the base in the lying position.

The leg telescopic unit is connected with a front cross rod, the seat support is fixedly connected with a rear cross rod, and the front cross rod can move forwards relative to the rear cross rod through the electric actuating unit so that the footstool can move to the front of the seat.

In a particularly preferred embodiment, the rear rail is directly or indirectly fastened or rigidly connected to the seat support.

In a particularly preferred embodiment, the tilting mechanism further comprises a linkage for linking the leg extension unit to the backrest support, which linkage is pivotally connected to the backrest support and the leg extension unit, such that the backrest support can be tilted back about a backrest pivot point at which the backrest support is pivotally connected to the seat support while the leg extension unit is extended forward, and the backrest support can be tilted forward about the backrest pivot point while the leg extension unit is retracted back.

In one embodiment, the linkage is formed by at least one-piece linkage link, by which the synchronous movement of the backrest support and the leg extension unit is achieved by a pivotal connection of the linkage link on the one hand to the backrest support and on the other hand to the leg extension unit. In this embodiment, the linkage link is directly pivotally connected at one end to the backrest support and at its other end to the leg extension unit, preferably to the foot bar of the leg extension unit closest to the seat support.

In this embodiment, the linkage preferably comprises a backrest connection in addition to the linkage link for structural stability. Wherein the backrest connecting piece is pivotally connected with its upper end to the backrest support at a pivot point behind the backrest pivot point, the backrest connecting piece is pivotally connected with its lower end to the rear end of the linkage link, and the front end of the linkage link is pivotally connected with the leg extension unit, preferably with the leg of the leg extension unit closest to the seat support. In this case, the simultaneous tilting of the backrest support back and the forward extension of the leg extension unit and the simultaneous tilting of the backrest support back and the rearward retraction of the leg extension unit are achieved by means of a simple linkage, so that the conversion of the seat unit between the sitting position and the lying position is achieved in a simple and reliable manner.

In order to achieve a more advantageous change of the seating unit between the sitting and lying position, it is also preferred that the support assembly comprises a drive link fixedly connected to the seat support, wherein a support link is arranged between the drive link and the seat support, which support link is connected, preferably fixedly connected, or can also be pivotally connected, at one end to the drive link and at the other end to the seat support for achieving a fixation of the relative position between the drive link and the seat support. In this way, the seat support can be kept in a stable position relative to the support assembly during the change of the position of the seat unit, so that it is ensured that the pivot point between the seat support and the backrest support, i.e. the position of the backrest pivot point relative to the support assembly, remains unchanged, which is advantageous for the backrest support to be turned forward or backward under the drive of the backrest connection.

In a preferred embodiment, the mechanical stretching device comprises an electric actuating unit, which is preferably designed as a linear motor unit, the components of which are connected to the front rail and the rear rail, respectively.

In this embodiment, the linear motor unit preferably comprises a motor head, a motor rail connected to the motor head, and a motor slide which is slidable relative to the motor rail. One end of the electric actuating unit, such as a motor head, is pivotally connected to a front cross bar fixedly connected with the leg extension unit, and the other end of the electric actuating unit, such as a motor slider, is pivotally connected to a rear cross bar fixedly connected with the seat support, so that when the motor head moves longitudinally relative to the motor slider along the longitudinal axis of the motor sliding rail, the front cross bar drives the leg extension unit to extend forwards or retract backwards, thereby changing the seat unit between the sitting position and the lying position. The opposite design is of course also possible, for example, by a motor slide of the electric actuating unit being pivotably connected to a front rail fixedly connected to the leg extension unit, and a motor head of the electric actuating unit being pivotably connected to a rear rail fixedly connected to the seat support.

The mechanical stretcher further comprises a base for supporting directly on the ground, and the supporting assembly is fixedly supported on the base. The base may be a circular bracket designed to be supported on the ground, to which a fixed bracket consisting of a set of parallel extending support rods is rotatably connected, so that the seat unit has a tilting, swinging/rocking function as well as a rotating function. Alternatively, the base may also be simply constructed as a set of parallel extending ground engaging brackets supported directly on the ground.

Preferably, the support assembly comprises a mounting swing base plate, a front swing rod, a rear swing rod and a transmission connecting rod, wherein the swing base plate is mounted on the base at the bottom of the base plate, the front end of the swing base plate is pivotally connected with the top end of the front swing rod, the rear end of the swing base plate is pivotally connected with the top end of the rear swing rod, and the transmission connecting rod is respectively pivotally connected with the lower end of the front swing rod and the lower end of the rear swing rod.

The invention further relates to a movable seating unit, comprising: a base for supporting on the ground, a seat part above the base, a backrest behind the seat part, a footstool in front of or below the seat part, and the mechanical stretching device. The movable seat unit may be a movable swing, a rocking chair, a sofa having a swinging or rocking function, or the like.

Drawings

Embodiments of the present invention are specifically described below with reference to the drawings.

Fig. 1 shows a perspective view of an embodiment of a mechanical stretching device of a seating unit configured as a swing according to the invention in a sitting position;

FIG. 2 shows a side view of the mechanical stretching device according to FIG. 1;

FIG. 3 shows a perspective view of the mechanical stretcher according to FIG. 1 in a lying position;

FIG. 4 shows a side view of the mechanical stretching device according to FIG. 3;

fig. 5a and 5b show a swing-released state and a swing-limited state, respectively, of a swing-limiting mechanism for a mechanical stretching device according to the invention;

FIG. 6 illustrates a perspective view of an embodiment of a mechanical extension device configured as a seat unit of a swing in a seated position according to the present disclosure;

FIG. 7 shows a side view of an embodiment of the mechanical stretching device according to FIG. 6;

FIG. 8 shows a perspective view of the mechanical stretcher according to FIG. 6 in a lying position; and is also provided with

Fig. 9 shows a side view of the mechanical stretching device according to fig. 8.

Detailed Description

An embodiment of a mechanical stretching device for a movable seating unit is first shown by way of example in fig. 1. The seat unit includes: a base 1, a tilting mechanism 2, a support assembly 3, and an electric actuating unit 4.

The base 1 can be designed as a circular support 11 supported on the ground as shown in fig. 1, to which a fixed support 12 consisting of a set of parallel support rods is rotatably connected.

Alternatively, in other embodiments not shown, the base 1 may also be configured as a set of parallel-extending ground-contacting brackets supported directly on the ground.

Above the base 1, in particular in the exemplary embodiment shown in fig. 1, a tilting mechanism 2 is fixedly connected to a fixing bracket 12. The tilting mechanism is arranged mirror-symmetrically on both the left and right sides with reference to the longitudinal direction of the seat unit, of which only half is shown and specifically explained here for the sake of simplicity. The reclining mechanism includes a seat bracket 21, a backrest bracket 22, and a leg extension unit 23.

In this embodiment, the backrest support 22 is configured with a horizontal section 221 extending substantially horizontally and a vertical section 222 extending substantially vertically in the sitting position, at the front end of which the backrest support 22 is pivotably connected with the rear end of the seat support 21 at a backrest pivot point M about which the backrest support 22 can be flipped back and forth.

As shown in fig. 1 to 4, the leg extension unit 23 is composed of a plurality of links pivotally connected to each other, wherein the seat bracket 21 is pivotally connected to the rear end of the front link 230 at a first pivot point a, the front end of the front link 230 is pivotally connected to the rear end of the first foot lever 231 at a second pivot point B, the front ends of the first foot lever 231 and the second foot lever 232 are respectively pivotally connected to the footrest support plate 234, the rear end of the second foot lever 232 is pivotally connected to the front end of the third foot lever 233 at a third pivot point C, the rear end of the third foot lever 233 is pivotally connected to the seat bracket 3 at a fourth pivot point D, and the second foot lever 232 is in turn pivotally connected to the front link 230 at a fifth pivot point E.

As shown in fig. 2 and 4, the reclining mechanism 2 further includes a linkage 24, the linkage 24 including a backrest connector 241 and a linkage link 242 extending generally longitudinally of the seat unit. In the design shown, the linkage link 242 is pivotably connected at its front end at a sixth pivot point F to the middle of the third foot bar 233 of the leg extension unit 23, and the linkage link 242 is pivotably connected at its rear end at a seventh pivot point G to the backrest link 241, which backrest link 241 is pivotably connected at an eighth pivot point H to the backrest bracket 22.

The mechanical stretching device further comprises a support assembly 3. As shown in fig. 1 and 3 in particular, the support assembly 3 includes a swing base plate 31, a front swing lever 32, a rear swing lever 33, and a transmission link 34, wherein the bottom of the swing base plate 31 is fixedly connected to the fixed bracket 12 of the base 1, the swing base plate 31 is pivotally connected to the top end of the front swing lever 32 with the front end at the top thereof, the swing base plate 31 is pivotally connected to the top end of the rear swing lever 33 with the rear end at the top thereof, and the lower ends of the front swing lever 32 and the rear swing lever 33 are respectively pivotally connected to the transmission link 34 extending lengthwise.

Preferably, in the embodiment shown, the drive link 34 is fixedly connected, in particular riveted or welded, with its front end to the seat support 21 and is pivotably connected with its rear end to the backrest connection 241 via the rear connection 243. In the design shown, the top end of the rear link 243 is pivotally connected to the back link 241 at a ninth pivot point I and the lower end of the rear link 243 is pivotally connected to the rear end of the drive link 34 at a tenth pivot point J.

In a preferred embodiment, a support link 35 is additionally provided between the transmission link 34 and the seat support 21, said support link 35 being pivotably connected at one end to the transmission link 34 and being fixedly connected at the other end to the seat support 21, so that, in combination with the fixed connection of the transmission link 34 to the seat support 21, a fixed relative position between the transmission link 34 and the seat support 21 is achieved.

As shown in particular in fig. 1 and 3, the seat unit further comprises an electric actuating unit 4, which in this embodiment is a linear motor unit, comprising a motor head 41, a motor rail 42 connected to the motor head 41 and a motor slider 43 slidable relative to the motor rail 42, wherein the motor head 41 is pivotably connected to a front rail 44 fixedly connected to a front connection 230 of the leg extension unit 23, the motor slider 43 is pivotably connected to a rear rail 45, and the rear rail 45 is fixedly connected at both ends to the middle of the seat support 21 by means of intermediate connections 46, respectively. Thus, as the motor head 41 moves longitudinally back and forth along the motor track 42 relative to the motor slider 43, the front rail 44 drives the leg extension unit 230 to extend forward or retract rearward through the front link 230.

The operation of the seat unit between the sitting position and the lying position is described below with reference to fig. 1 to 4.

In the sitting position as shown in fig. 1 and 2, the back support 22 is oriented generally vertically, the seat support 21 is oriented generally horizontally, the footrest support plate 234 is oriented generally vertically and the leg extension unit 23 is fully stowed under the seat support 21; in the lying position as shown in fig. 3 and 4, the leg extension unit 23 is fully extended forward and the back support 22 is fully reclined.

When the motor head 41 is operated in the forward direction, the position of the seat support 3 is kept unchanged basically in the longitudinal direction due to the gravity action of a user, the motor head 41 moves forward along the motor sliding rail 42 relative to the motor sliding block 43, so that the distance between the motor head 41 and the motor sliding block 43 is increased, the front cross bar 44 drives the front connecting piece 230 to rise forward, and the leg telescopic unit 23 is fully unfolded from the folded state in the sitting position shown in fig. 1 and 2 to the unfolded state in the lying position shown in fig. 3 and 4. At the same time, as the leg extension and retraction unit 23 is unfolded, the link lever 242 pivotally connected to the third leg lever 233 of the leg extension and retraction unit 23 at the sixth pivot point F is correspondingly moved forward, thereby moving the seventh pivot point G connecting the rear end of the link lever 242 and the backrest link 241 forward. Since the relative position between the seat bracket 21 and the drive link 34 is fixed, the position of the back pivot point M remains substantially unchanged during deployment of the leg extension unit 23, thereby driving the eighth pivot point H on the back link 241 downward, thereby pulling the back bracket 22 back and down around the back pivot point M. Thereby, the backward tilting of the back support 22 is achieved while the leg extension and contraction unit 23 is extended forward, thereby achieving the conversion of the seat unit from the sitting position to the lying position.

Starting from the lying position shown in fig. 3 and 4, if the motor head 41 is operated in reverse, the motor head 41 moves along the motor slide rail 42 toward the motor slider 43, so that the distance between the motor head 42 and the motor slider 43 is shortened, and the leg extension and retraction unit 23 is retracted rearward, thereby driving the linkage link 242 to move rearward and pushing the seventh pivot point G of the backrest link 241 to move rearward. At the same time, the eighth pivot point H on the back link 241 moves upward, pushing the back bracket 22 upward and forward about the back pivot point, again due to the fixed position of the back pivot point M. Thereby, the forward resetting inclination of the backrest support 22 is realized while the leg extension unit 23 is retracted rearward, thereby realizing the conversion of the seat unit from the lying position to the sitting position.

In a preferred embodiment, as shown in fig. 3 to 5b, the mechanical stretching device has a pivot stop 25, which comprises a first stop 251, a second stop 252, a slide stop 253 and a stop link 254. The first limiting member 251 is pivotally connected to the transmission connecting rod 34 at a limiting pivot point K in the middle, a first limiting bushing 251a is provided at the front end of the first limiting member 251, the rear end of the first limiting member 251 is pivotally connected to the front end of the second limiting member 252, and a second limiting bushing 252a is provided at the rear end of the second limiting member 252. The chute limiting member 253 is fixedly connected to the transmission connecting rod 34 and extends upwards from the transmission connecting rod to form a section with a limiting chute 253a, and the second limiting bushing 252a is movably embedded in the swinging limiting chute 253 a. One end of the limit link 254 is pivotally connected between the limit pivot point K of the first limit member 251 and the first limit bushing 251a, and the other end thereof is pivotally connected with the link lever 242, so that the limit link 254 can be moved under the drive of the link lever 242, whereby the swing limit mechanism 25 can be switched between the swing release state and the swing limit state.

In the swing release state as shown in fig. 5a, the seat unit is in the sitting position, the first and second limit bushings 251a and 252a are out of contact with both the front and rear swing levers 32 and 33, allowing for a front-rear pivotal movement of the front and rear swing levers 32 and 33, so that the reclining mechanism 2 can swing back and forth relative to the base 1. When the seat unit is converted from the sitting position to the lying position, the leg extension and retraction unit 23 is unfolded, the linkage link 242 is caused to move forward, and the limit link 254 is also caused to move forward under the traction of the linkage link 242, so that the first limit piece 251 is driven to pivot around the limit pivot point K, and the first limit bushing 251a thereof is moved until the first limit bushing 251a abuts against the inner side of the front swing lever 32; at the same time, the rear end of the first stopper 251 moves rearward, thereby pushing the second stopper 252 with its second stopper bush 252a moving rearward in the stopper slide groove 253a of the third stopper 253 until the second stopper bush 252a abuts against the inner side of the rear swing lever 33. The swing limit state shown in fig. 5b is thereby reached, whereby the pivoting of the front and rear swing levers 32, 33 is prevented, so that the tilting mechanism 2 can no longer swing back and forth with respect to the base 1.

Fig. 6 to 9 show an embodiment of a mechanical extension device in the form of a rocking chair. The swing substrate 31 'may be replaced with the swing substrate in the support assembly, and the swing substrate 31' may be attached to the base 1 having a swing function at the bottom thereof. In the embodiment shown, the rocking base plate 31 'is mounted on a set of parallel extending ground-contacting brackets 13 configured to be supported directly on the ground, the drive connection rods of the bearing assembly 3 being fixedly connected to the rocking base plate 31'. In this embodiment, the drive link is composed of a first generally vertically extending drive link part 341 and a second generally longitudinally extending drive link part 342 fixedly connected adjacent to the leg extension unit 23, although the drive link may also be constructed in one piece as in the embodiment of the swing.

A support link 35 is likewise arranged between the drive link and the seat support 21, one end of the support link 35 being fixedly connected to the seat support 21 and the other end being fixedly connected to the drive link, in this embodiment to the drive link second part 342 of the drive link. The mechanical stretching device thus also ensures a fixed relative position between the seat support 21 and the transmission connecting rod during the transition between the sitting position and the lying position.

An eleventh pivot point L is additionally provided on the back link 241 between the seventh pivot point G and the ninth pivot point I. In this embodiment, the support assembly 3 further comprises a first auxiliary link 36 and a second auxiliary link 37, wherein one end of the first auxiliary link 36 is pivotally connected to the back link 241 by means of an eleventh pivot point L. The second auxiliary link 37 is provided with an auxiliary bushing 37a on one end thereof and the other end not provided with an auxiliary bushing is pivotally connected to the drive link, in this embodiment preferably to the drive link second part 342. The other end of the first auxiliary connecting rod 36 is pivotally connected to the second auxiliary connecting rod 37 near its auxiliary pivot point N of the auxiliary bushing 37 a. The remaining technical features that are the same as those of the embodiment of fig. 1 to 4 are not described in detail herein.

Fig. 6 and 7 show a configuration in which the seat unit of the rocking chair is designed to be in a sitting position. As shown in fig. 6 and 7, the first auxiliary link 36 is pivotally connected to the second auxiliary link 37 by means of an auxiliary pivot point N, in which case an auxiliary bushing 37a at the end of the second auxiliary link 37 is spaced from the base 1, in this embodiment from the ground engaging support 13. In the lying position shown in fig. 8 and 9, the auxiliary bushing 37a rests against the base 1.

When the mechanical stretching device is changed from the sitting position shown in fig. 6 and 7 to the lying position shown in fig. 8 and 9, the leg extension and contraction unit 23 is driven by the electric actuating unit 4 to extend forward, so that the linkage link 242 is driven to move forward, and the backrest connecting member 241 is driven to turn over, so that the seventh pivot point G on the backrest connecting member 241 moves forward, in which case the backrest bracket 22 is driven by the backrest connecting member 241 to turn back around the backrest pivot point M because the position of the backrest pivot point M relative to the transmission link is kept fixed. At the same time, the eleventh pivot point L on the backrest connection 241 also moves forward, since one end of the second auxiliary link 37 is pivotally connected to the fixed transmission link, in this embodiment to the transmission link second part 342, pushing the auxiliary pivot point N between the first auxiliary link 36 and the second auxiliary link 37 downward and causing the second auxiliary link 37 to pivot downward with its end provided with the auxiliary bushing 37a about its pivot point on the transmission link second part 342 until the auxiliary bushing 37a abuts against the base 1, preferably against the ground contact bracket 13. In this embodiment, the tilting mechanism 2 is prevented from rocking backwards in the lying position by means of the auxiliary bushing 37a, additional support of the backrest support in the lying position is achieved, so that the risk of tipping over due to excessive reclining of the backrest in the lying position is prevented, ensuring the safety of the use of the seat.

List of reference numerals

1. Base seat

11. Round support

12. Fixing support

13. Ground contact support

2. Tilting mechanism

21. Seat support

22. Backrest support

221. Horizontal section

222. Vertical section

23. Leg telescopic unit

230. Front connecting piece

231. First foot bar

232. Second foot bar

233. Third foot bar

234. Foot stool support plate

24. Linkage device

241. Backrest connecting piece

242. Linkage connecting rod

243. Rear connecting piece

25. Swing limiting mechanism

251. First limiting piece

251a first spacing bush

252. Second limiting piece

252a second spacing bush

253. Chute limiting piece

253a limiting chute

254. Spacing connecting rod

3. Support assembly

31. Swing substrate

31' shaking the substrate

32. Front swinging rod

33. Rear swing lever

34. Transmission connecting rod

341. First sub-part of transmission connecting rod

342. Second part of transmission connecting rod

35. Support connecting rod

36. First auxiliary connecting rod

37. Second auxiliary connecting rod

4. Electric actuating unit

41. Motor head

42. Motor slide rail

43. Motor sliding block

44. Front cross bar

45. Rear cross bar

46. Intermediate connecting piece

A first pivot point

B second pivot point

C third pivot point

D fourth pivot point

E fifth pivot point

F sixth pivot point

G seventh pivot point

H eighth pivot point

I ninth pivot point

J tenth pivot point

K-limit pivot point

L eleventh pivot point

M back pivot point

N auxiliary pivot points.

Claims

1. A mechanical stretcher for a movable seating unit, comprising:

a tilting mechanism (2) comprising a multi-link mechanism and for attachment to a seat portion, a backrest and a footrest of the seat unit, configured to enable a change of the seat unit between two end positions, namely a sitting position in which the footrest is folded under the seat portion, and a lying position; in the recumbent position, the backrest is reclined and the footrest is extended forward to the front of the seat portion;

wherein the tilting mechanism (2) is configured such that the seat unit is changed between a sitting position and a lying position by an electric actuating unit (4), wherein, when the seat unit is changed from the sitting position to the lying position, the footrest is extended forward to the front of the seat portion while the backrest is tilted backward, and when the seat unit is changed from the lying position to the sitting position, the footrest is retracted backward to be folded under the seat portion while the backrest is tilted forward,

wherein the tilting mechanism (2) comprises: the leg telescopic unit (23) for mounting the footstool, the seat support (21) for mounting the seat part and the backrest support (22) for mounting the backrest are sequentially connected in a pivoted mode, the linkage device (24) is used for enabling the leg telescopic unit (23) to be linked with the backrest support (22), and the linkage device is connected with the backrest support (22) and the leg telescopic unit (23) in a pivoted mode, so that the backrest support (22) can be turned backwards around a backrest pivot point (M) where the backrest support (22) is connected with the seat support (21) in a pivoted mode while the leg telescopic unit (23) is extended forwards, and the backrest support (22) can be turned forwards around the backrest pivot point (M) while the leg telescopic unit (23) is folded backwards.

2. A mechanical stretching device according to claim 1, wherein the mechanical stretching device comprises a support assembly (3) for direct or indirect support on the ground.

3. A mechanical stretching device according to claim 2, wherein the support assembly (3) is adapted to provide a swinging or rocking function for the seat unit.

4. Mechanical stretching device according to claim 1, wherein the tilting mechanism (2) is configured for swinging or rocking the seat unit, allowing the seat unit to swing or rock back and forth with respect to the ground in the sitting position and not allowing the seat unit to swing or rock back and forth with respect to the ground in the lying position.

5. The mechanical stretching apparatus according to claim 1, wherein a front cross bar (44) is connected to the leg extension unit (23), and a rear cross bar (45) is fixedly connected to the seat support (21), wherein the front cross bar (44) can be moved forward relative to the rear cross bar (45) by the electric actuating unit (4) to move the footrest in front of the seat.

6. Mechanical stretching apparatus according to claim 5, wherein the rear cross-bar (45) is directly or indirectly fixed or rigidly connected to the seat support (21).

7. The mechanical stretcher according to claim 1 wherein the linkage (24) comprises a backrest connecting member (241) and a linkage link (242), wherein the backrest connecting member (241) is pivotally connected at its upper end to the backrest bracket (22) at a pivot point behind the backrest pivot point (M), the backrest connecting member is pivotally connected at its lower end to the rear end of the linkage link (242), and the front end of the linkage link (242) is pivotally connected to the leg extension unit (23).

8. The mechanical stretching device according to claim 7, wherein the front end of the linkage link (242) is pivotally connected to the foot bar of the leg extension unit (23) closest to the seat support (21).

9. Mechanical stretching device according to claim 2, wherein the support assembly (3) comprises a transmission connection rod (34) fixedly connected to the seat support (21), wherein a support connection rod (35) is arranged between the transmission connection rod (34) and the seat support (21), said support connection rod being connected at one end to the transmission connection rod (34) and at the other end to the seat support (21).

10. A mechanical stretching device according to claim 9, wherein the support link is fixedly connected at one end to the transmission link (34) and at the other end to the seat support (21).

11. The mechanical stretching device according to claim 5, further comprising an electric actuation unit (4), the constituent parts of which are connected to the front crossbar (44) and the rear crossbar (45), respectively.

12. Mechanical stretching apparatus according to claim 11, wherein the electric actuation unit (4) is designed as a linear motor unit.

13. A mechanical stretching device according to claim 2, wherein the mechanical stretching device further comprises a base (1) for supporting directly on the ground, the support assembly (3) being fixedly supported on the base.

14. A movable seating unit, the seating unit comprising: a base (1) for supporting on the ground, a seat portion above the base (1), a backrest behind the seat portion, a footstool in front of or below the seat portion, a mechanical stretching device according to any one of the preceding claims 1 to 13.