CN212466520U - Double-slide-rail massage chair with front-back sliding and dumping angle adjusted cooperatively - Google Patents

Abstract

The utility model provides a massage armchair that slides around two slide rail formulas and topple angle and adjust in coordination, include: the base frame comprises a main body mounting frame, and a first slide way and a second slide way are symmetrically arranged on the main body mounting frame along the left and right sides of the massage chair; the seat frame is symmetrically provided with hinge structures and walking structures along the left and right sides of the massage chair, the hinge structures on the two sides are in one-to-one correspondence with the first slide ways on the two sides and are in motion fit with the first slide ways on the two sides, and the walking structures on the two sides are in one-to-one correspondence with the second slide ways on the two sides and are in motion fit with the second slide ways on the two sides; the backrest frame is rotatably connected with the seat frame through a hinge structure at two sides of the backrest frame along the left and right directions of the massage chair respectively; the driving system comprises a first driving device and a second driving device. The utility model discloses reduce the whole weight and the manufacturing cost of massage armchair, optimized the running space of massage armchair, improved the massage experience of massage armchair.

Description

Double-slide-rail massage chair with front-back sliding and dumping angle adjusted cooperatively

Technical Field

The utility model relates to a massage equipment technical field especially relates to a massage armchair of sliding and dumping angle in coordination regulation around two slide rail formulas.

Background

The common massage armchair on the market at present is that the seat slides forward a certain distance after being electrified, and then wholly topples over backward, so that not only a large operation space is needed, but also a user waits for the forward sliding time, the experience feeling is greatly reduced, and the massage form is single, the included angle between the thigh and the backrest cannot be changed, and the stretching of the waist and the abdomen of the user cannot be effectively helped.

SUMMERY OF THE UTILITY MODEL

In view of the above prior art's shortcoming, the to-be-solved technical problem of the utility model is to provide a massage armchair who slides around two slide rail formulas and empty angle and adjust in coordination, the cooperation of motion of ingenious first slide of application and hinge structure and the cooperation of motion of second slide and walking structure to under driving about of first drive arrangement, still realize the seat frame and for empting of base frame when realizing that the seat frame slides towards the massage armchair fore-and-aft direction. The second driving device can adjust the included angle between the seat frame and the backrest frame to the most comfortable angle. The utility model discloses a massage armchair has reduced massage armchair's whole weight and manufacturing cost, has optimized massage armchair's operating space, has improved massage armchair's massage experience.

In order to solve the technical problem, the utility model provides a massage armchair who slides around two slide rail formulas and empty angle is adjusted in coordination, include:

the base frame comprises a main body mounting frame, a first slide way and a second slide way are symmetrically arranged on the main body mounting frame along the left side and the right side of the massage chair, the first slide way is positioned above the second slide way and extends along the front-back direction of the massage chair, and the distance between the second slide way and the first slide way is gradually reduced from the back of the massage chair to the front of the massage chair;

the seat frame is symmetrically provided with hinge structures and walking structures along the left and right sides of the massage chair, the hinge structures on the two sides are in one-to-one correspondence with the first slide ways on the two sides and are in motion fit with the first slide ways on the two sides, and the walking structures on the two sides are in one-to-one correspondence with the second slide ways on the two sides and are in motion fit with the second slide ways on the two sides;

the backrest frame is rotatably connected with the seat frame through a hinge structure at two sides of the backrest frame along the left and right directions of the massage chair respectively;

the driving system comprises a first driving device and a second driving device, the first driving device is used for driving the seat frame to move under the common guiding and restraining of the first slide way and the second slide way, and the second driving device is used for adjusting an included angle between the seat frame and the backrest frame.

Preferably, the first slideway is a straight chute with an opening facing the seat frame, the hinge structure comprises a hinge shaft for hinging the seat frame and the backrest frame together, and the hinge shaft is provided with a rolling wheel arranged in the straight chute in a rolling manner.

Preferably, the seat frame has a first ear plate member at a portion close to the back frame, and the back frame has a second ear plate member at a portion close to the seat frame, and the first ear plate member is hinged to the second ear plate member through a hinge shaft.

Preferably, the seat frame is provided with a tilting adjusting hole extending along an arc track, the circle center corresponding to the tilting adjusting hole is positioned on the axis of the hinge shaft, the backrest frame is provided with a restraining wheel, and the restraining wheel moves along with the backrest frame and is always positioned in the tilting adjusting hole.

Preferably, the second slide is the crooked spout of opening towards the seat frame, the walking structure includes the restraint axle of empting of being connected with the seat frame, emptys to be equipped with on the restraint axle and rolls the walking wheel of setting in crooked spout.

Preferably, the massage chair further comprises a massage mechanism, the massage mechanism comprises a flexible track and a massage machine core, the flexible track is laid from the backrest frame to the seat frame, and the massage machine core is movably arranged on the flexible track.

Preferably, the massage chair further comprises a lower leg frame rotatably connected to the seat frame, and the driving system further comprises a third driving device for adjusting an included angle between the lower leg frame and the seat frame.

Preferably, the third driving device comprises a driving swing rod and a third expansion piece, one end of the driving swing rod is hinged to the seat frame, the other end of the driving swing rod is provided with an abutting wheel in rolling fit with the shank frame, and the third expansion piece is arranged between the driving swing rod and the seat frame.

Preferably, the extension length of the second slide is greater than that of the first slide, one end of the second slide facing the back of the massage armchair is vertically aligned with one end of the first slide facing the back of the massage armchair, and one end of the second slide facing the front of the massage armchair exceeds one end of the first slide facing the front of the massage armchair.

Preferably, the first driving device comprises a first expansion piece, and two ends of the first expansion piece in the expansion direction are respectively hinged with the main body mounting frame and the seat frame; the second driving device comprises a second expansion piece, and two ends of the second expansion piece in the expansion direction are hinged with the seat frame and the backrest frame respectively.

As mentioned above, the utility model discloses a massage armchair who slides around two slide rail formulas and empty angle and adjust in coordination has following beneficial effect: when the first driving device of the driving system drives the seat frame to move towards the front of the massage armchair, on one hand, the seat frame is symmetrically provided with hinge structures along the left and right sides of the massage armchair, the hinge structures at the two sides are in one-to-one correspondence with the first slide ways at the two sides and are in motion fit, and the seat frame slides along the extending direction of the first slide ways through the hinge structures; on the other hand, the two sides of the seat frame along the left and right direction of the massage chair are symmetrically provided with walking structures, the walking structures on the two sides are in one-to-one correspondence with the second slide ways on the two sides and are in motion fit, and the seat frame also slides along the extending direction of the second slide ways through the walking structures. More importantly, the first slide way is positioned above the second slide way and extends along the front-back direction of the massage armchair, the distance between the second slide way and the first slide way is gradually reduced from the back of the massage armchair to the front of the massage armchair, and the seat frame slides towards the front of the massage armchair and inclines towards the back of the massage armchair while being guided and constrained by the first slide way and the second slide way. The second drive device may be operated simultaneously with the first drive device or may be operated at a different time from the first drive device. Under the driving of the second driving device, the included angle between the seat frame and the backrest frame changes, so that the waist and abdomen of a user of the massage chair can be rolled or stretched, and a better massage effect can be obtained. When the first driving device drives the seat frame to move towards the back of the massage armchair, the seat frame returns to the original state in the same way; when the second driving device drives the backrest frame to swing relative to the seat frame, the included angle between the seat frame and the backrest frame is restored to the original angle. Therefore, the utility model discloses a massage armchair who slides around two slide rail formulas and empty angle and adjust in coordination uses the motion cooperation of first slide and hinge structure and the motion cooperation of second slide and walking structure ingeniously to under driving system's a drive arrangement orders about, still realize falling of seat frame for the base frame when realizing that the seat frame slides towards the massage armchair fore-and-aft direction. The second driving device can adjust the included angle between the seat frame and the backrest frame to the most comfortable angle. The utility model discloses a massage armchair no longer uses original expensive guide rail structure, has reduced massage armchair's whole weight and manufacturing cost, has optimized massage armchair's operating space, has improved massage armchair's massage experience.

Drawings

Fig. 1 is a perspective view showing a first use state of the massage chair with the double-sliding-rail type forward and backward sliding and pouring angle cooperatively adjusted according to the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is an enlarged view of portion B of FIG. 1;

FIG. 4 is a perspective view of the dual-sliding track type massage chair with forward and backward sliding and dumping angle adjusted in cooperation with the present invention in a second use state;

FIG. 5 is a first perspective view of a massage chair with dual sliding tracks for adjusting forward and backward movement and a tilting angle in cooperation with each other according to a third embodiment of the present invention;

FIG. 6 is a second perspective view of the massage chair of the present invention in a third use state, wherein the two-sliding-rail type massage chair is adjusted in cooperation with the forward and backward sliding and tilting angles;

FIG. 7 is an enlarged view of portion C of FIG. 6;

figure 8 shows a perspective view of the base frame.

Description of the element reference numerals

1 base frame

11 main body mounting rack

111 pad base frame

112 supporting rack

12 first slideway

13 second slideway

2 seat frame

21 first ear plate member

22 dumping adjusting hole

3 backrest frame

31 second ear plate member

32 restrain wheel

4 drive system

41 first drive device

411 first expansion piece

42 second drive device

421 second expansion piece

43 third drive device

431 drive pendulum rod

432 third expansion joint

433 leaning wheel

5 hinge structure

51 articulated shaft

52 rolling wheel

6 walking structure

61 toppling restraining shaft

62 road wheel

7 Flexible track

Detailed Description

The following description is provided for illustrative purposes, and other advantages and features of the present invention will become apparent to those skilled in the art from the following detailed description.

It should be understood that the structures, ratios, sizes, etc. shown in the drawings of the present specification are only used for matching with the contents disclosed in the specification, so as to be known and read by those skilled in the art, and are not used for limiting the limit conditions that the present invention can be implemented, so that the present invention has no technical essential meaning, and any modification of the structures, changes of the ratio relationship, or adjustment of the sizes should still fall within the scope covered by the technical contents disclosed in the present invention without affecting the efficacy and the achievable purpose of the present invention. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof may be made without substantial technical changes, and the present invention is also regarded as the scope of the present invention.

As shown in fig. 1 to 8, the utility model provides a massage chair with double slide rails capable of sliding forwards and backwards and adjusting pouring angle in coordination, which comprises:

the massage chair comprises a base frame 1, wherein the base frame 1 comprises a main body mounting frame 11, a first slide way 12 and a second slide way 13 are symmetrically arranged on two sides of the main body mounting frame 11 along the left-right direction of the massage chair, the first slide way 12 is positioned above the second slide way 13 and extends along the front-back direction of the massage chair, and the distance between the second slide way 13 and the first slide way 12 gradually decreases from the back of the massage chair to the front of the massage chair;

the two sides of the seat frame 2 along the left and right direction of the massage chair are symmetrically provided with a hinge structure 5 and a walking structure 6, the hinge structures 5 at the two sides are in one-to-one correspondence with the first slide ways 12 at the two sides and are in motion fit, and the walking structures 6 at the two sides are in one-to-one correspondence with the second slide ways 13 at the two sides and are in motion fit;

the backrest frame 3, the two sides of the backrest frame 3 along the left and right direction of the massage chair are respectively connected with the seat frame 2 through the hinge structure 5 in a rotating way;

the driving system 4, the driving system 4 comprises a first driving device 41 and a second driving device 42, the first driving device 41 is used for driving the seat frame 2 to move under the common guiding constraint of the first slideway 12 and the second slideway 13, and the second driving device 42 is used for adjusting the included angle between the seat frame 2 and the backrest frame 3.

In the present invention, when the first driving device 41 of the driving system 4 drives the seat frame 2 to move towards the front of the massage chair, on one hand, since the seat frame 2 is symmetrically provided with the hinge structures 5 along the two sides of the left and right direction of the massage chair, the hinge structures 5 on the two sides are in one-to-one correspondence with the first slide ways 12 on the two sides and are in motion fit with the first slide ways 12 on the two sides, the seat frame 2 slides along the extending direction of the first slide ways 12 through the hinge structures 5; on the other hand, the two sides of the seat frame 2 along the left and right direction of the massage chair are symmetrically provided with the walking structures 6, the walking structures 6 on the two sides are in one-to-one correspondence with the second slide ways 13 on the two sides and are in motion fit, and the seat frame 2 also slides along the extending direction of the second slide ways 13 through the walking structures 6. More importantly, the first slide way 12 is positioned above the second slide way 13 and extends along the front-back direction of the massage armchair, the distance between the second slide way 13 and the first slide way 12 is gradually reduced from the back of the massage armchair to the front of the massage armchair, and the arrangement is that under the common guiding constraint of the first slide way 12 and the second slide way 13, the seat frame 2 slides towards the front of the massage armchair and inclines towards the back of the massage armchair at the same time. The second driving device 42 may be operated simultaneously with the first driving device 41, or may be operated not simultaneously with the first driving device 41. Under the driving of the second driving device 42, the included angle between the seat frame 2 and the backrest frame 3 changes, so that the waist and abdomen of the user of the massage chair can be rolled or stretched, and a better massage effect can be obtained. For example, the second driving device 42 increases the angle between the seat frame 2 and the backrest frame 3, so as to increase the angle between the body of the user of the massage chair and the thigh, thereby gradually and uniformly dispersing the gravity of the body on the whole massage chair, gradually bringing the body into a more natural and comfortable relaxed state, effectively releasing the physical and mental pressure, and relieving the fatigue of the waist and the back. As shown in fig. 5 and fig. 6, when the body of the massage armchair user is about 127 degrees to the thigh, the massage armchair user is in a zero gravity state (the massage armchair simulates the zero gravity state according to the basic principle of NASA zero gravity capsule chair of space general administration), and at the same time, the heart and the knees are on the same horizontal line, the pressure of the heart is effectively relieved, and the blood circulation is promoted, and at this time, the included angle between the seat frame 2 and the backrest frame 3 is called as a zero gravity included angle. As shown in fig. 1, when the first driving device 41 drives the seat frame 2 to move towards the back of the massage chair, the seat frame 2 returns to the original state in the same way; when the second driving device 42 drives the back frame 3 to swing relative to the seat frame 2, the angle between the seat frame 2 and the back frame 3 is restored to the original angle.

Therefore, the utility model discloses a massage armchair of sliding around two slide rail formulas and pouring angle in coordination with regulation skillfully utilizes the motion cooperation of first slide 12 and hinge structure 5 and the motion cooperation of second slide 13 and walking structure 6 to under ordering about of the first drive arrangement 41 of actuating system 4, still realize falling of seat frame 2 for base frame 1 when realizing that seat frame 2 slides towards the massage armchair fore-and-aft direction. The second drive means 42 are able to adjust the angle between the seat frame 2 and the back frame 3 to the most comfortable angle. The utility model discloses a massage armchair no longer uses original expensive guide rail structure, has reduced massage armchair's whole weight and manufacturing cost, has optimized massage armchair's operating space, has improved massage armchair's massage experience.

As shown in fig. 1 and 2, in order to reduce the frictional resistance between the hinge structure 5 and the first slide 12, the first slide 12 is a straight slide groove opened toward the seat frame 2, the hinge structure 5 includes a hinge shaft 51 for hinge-connecting the seat frame 2 and the back rest frame 3, and the hinge shaft 51 is provided with a rolling wheel 52 rolling in the straight slide groove.

As shown in fig. 2, in order to facilitate the articulation of the seat frame 2 and the back frame 3, a first ear plate member 21 is provided at a portion of the seat frame 2 adjacent to the back frame 3, a second ear plate member 31 is provided at a portion of the back frame 3 adjacent to the seat frame 2, and the first ear plate member 21 is articulated to the second ear plate member 31 by an articulated shaft 51.

As shown in fig. 3, in order to limit the included angle between the backrest frame 3 and the seat frame 2, the seat frame 2 is provided with a tilting adjustment hole 22 extending along an arc track, the center of a circle corresponding to the tilting adjustment hole 22 is located on the axis of the hinge shaft 51, the backrest frame 3 is provided with a restraint wheel 32, and the restraint wheel 32 moves along with the backrest frame 3 and is always located in the tilting adjustment hole 22.

As shown in fig. 6 to 8, in order to improve the motion synchronism and the motion stability of the seat frame 2 at both sides in the left-right direction of the massage chair, the second slide 13 is a curved chute with an opening facing the seat frame 2, the traveling structure 6 includes a tilting restriction shaft 61 connected to the seat frame 2, and a traveling wheel 62 is provided on the tilting restriction shaft 61 and is rotatably disposed in the curved chute.

As shown in fig. 5, the massage chair further comprises a massage mechanism, wherein the massage mechanism comprises a flexible track 7 and a massage mechanism, the flexible track 7 is laid from the backrest frame 3 to the seat frame 2, and the massage mechanism is movably arranged on the flexible track 7, so that the massage mechanism can massage the thighs, the buttocks, the back and the like of a user of the massage chair.

As shown in fig. 5, the massage chair further includes a lower leg frame (not shown) rotatably connected to the seat frame 2, and the driving system 4 further includes a third driving device 43 for adjusting an angle between the lower leg frame and the seat frame 2, wherein the third driving device 43 is used for adjusting the angle between the lower leg frame and the seat frame 2. Further, the third driving device 43 includes a driving swing rod 431 and a third retractor 432 (such as an electric push rod), one end of the driving swing rod 431 is hinged to the seat frame 2, the other end of the driving swing rod 431 is provided with a leaning wheel 433 which is in rolling fit with the shank frame, and the third retractor 432 is arranged between the driving swing rod 431 and the seat frame 2.

In order to be able to with the utility model discloses a massage armchair adjusts to zero gravity state, and the extension length of above-mentioned second slide 13 is greater than the extension length of first slide 12, and second slide 13 aligns from top to bottom towards the one end at massage armchair rear and first slide 12 towards the one end at massage armchair rear, and second slide 13 surpasss in the one end in first slide 12 towards the massage armchair the place ahead.

In order to simplify the structure of the first driving device 41 and the second driving device 42, the first driving device 41 includes a first telescopic device 411, and two ends of the first telescopic device 411 in the telescopic direction are respectively hinged with the main body mounting frame 11 and the seat frame 2; the second driving device 42 includes a second expansion piece 421, and two ends of the second expansion piece 421 in the expansion direction are respectively hinged to the seat frame 2 and the backrest frame 3. The first and second expanders 411 and 421 may be electric push rods.

As shown in fig. 8, in order to simplify the structure of the main body mounting frame 11, the main body mounting frame 11 includes a cushion bottom frame 111, support frames 112 are symmetrically disposed on both sides of the cushion bottom frame 111 along the left-right direction of the massage chair, and the support frames 112 on both sides are respectively in one-to-one correspondence with and connected to the first slide rail 12 and the second slide rail 13 on both sides.

To sum up, the utility model discloses a massage armchair who slides around two slide rail formulas and empty the angle and adjust in coordination uses the motion cooperation of first slide and hinge structure and the motion cooperation of second slide and walking structure to under driving arrangement's ordering about, still realize falling of seat frame for the base frame when realizing that the seat frame slides towards the massage armchair fore-and-aft direction. The second driving device can adjust the included angle between the seat frame and the backrest frame to the most comfortable angle. The utility model discloses a massage armchair has reduced massage armchair's whole weight and manufacturing cost, has optimized massage armchair's operating space, has improved massage armchair's massage experience. Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (10)

1. The utility model provides a massage armchair who slides and empty angle coordinate regulation around two slide rail formulas which characterized in that includes:

the massage chair comprises a base frame (1), wherein the base frame (1) comprises a main body mounting frame (11), a first slide way (12) and a second slide way (13) are symmetrically arranged on the main body mounting frame (11) along the left and right sides of the massage chair, the first slide way (12) is positioned above the second slide way (13) and extends along the front and back direction of the massage chair, and the distance between the second slide way (13) and the first slide way (12) is gradually reduced from the back of the massage chair to the front of the massage chair;

the massage chair comprises a seat frame (2), wherein hinge structures (5) and walking structures (6) are symmetrically arranged on two sides of the seat frame (2) along the left and right directions of the massage chair, the hinge structures (5) on the two sides correspond to first slide ways (12) on the two sides one by one and are in motion fit, and the walking structures (6) on the two sides correspond to second slide ways (13) on the two sides one by one and are in motion fit;

the backrest frame (3), the two sides of the backrest frame (3) along the left and right directions of the massage chair are respectively connected with the seat frame (2) in a rotating way through a hinge structure (5);

the driving system (4), the driving system (4) includes the first actuating device (41) and second actuating device (42), the first actuating device (41) is used for driving the seat frame (2) to move under the common guide constraint of the first slideway (12) and the second slideway (13), the second actuating device (42) is used for adjusting the included angle between seat frame (2) and the back frame (3).

2. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle according to claim 1, wherein: the first slide way (12) is a straight slide way with an opening facing the seat frame (2), the hinged structure (5) comprises a hinged shaft (51) which is hinged with the seat frame (2) and the backrest frame (3), and a rolling wheel (52) which is arranged in the straight slide way in a rolling way is arranged on the hinged shaft (51).

3. The massage chair with the double-sliding-rail type forward and backward sliding and the pouring angle adjusted in a coordinated manner according to claim 2, wherein: the part of the seat frame (2) close to the backrest frame (3) is provided with a first lug plate piece (21), the part of the backrest frame (3) close to the seat frame (2) is provided with a second lug plate piece (31), and the first lug plate piece (21) is hinged with the second lug plate piece (31) through a hinge shaft (51).

4. The massage chair with the double-sliding-rail type forward and backward sliding and the pouring angle adjusted in a coordinated manner according to claim 2, wherein: the seat frame (2) is provided with a dumping adjusting hole (22) extending along an arc track, the circle center corresponding to the dumping adjusting hole (22) is located on the axis of the hinged shaft (51), the backrest frame (3) is provided with a restraining wheel (32), and the restraining wheel (32) moves along with the backrest frame (3) and is always located in the dumping adjusting hole (22).

5. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle according to claim 1, wherein: the second slide (13) is the crooked spout of opening towards seat frame (2), walking structure (6) are equipped with the walking wheel (62) of rolling setting in crooked spout including empting restraint axle (61) of being connected with seat frame (2) on empting restraint axle (61).

6. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle according to claim 1, wherein: the massage chair further comprises a massage mechanism, the massage mechanism comprises a flexible track (7) and a massage machine core, the flexible track (7) is paved from the backrest frame (3) to the seat frame (2), and the massage machine core is movably arranged on the flexible track (7).

7. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle according to claim 1, wherein: the massage chair further comprises a shank frame which is rotatably connected with the seat frame (2), the driving system (4) further comprises a third driving device (43), and the third driving device (43) is used for adjusting an included angle between the shank frame and the seat frame (2).

8. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle as claimed in claim 7, wherein: the third driving device (43) comprises a driving swing rod (431) and a third expansion piece (432), one end of the driving swing rod (431) is hinged to the seat frame (2), an abutting wheel (433) which is matched with the shank frame in a rolling mode is arranged at the other end of the driving swing rod (431), and the third expansion piece (432) is arranged between the driving swing rod (431) and the seat frame (2).

9. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle according to claim 1, wherein: the extension length of the second slide way (13) is greater than that of the first slide way (12), one end, facing the back of the massage armchair, of the second slide way (13) is aligned with one end, facing the back of the massage armchair, of the first slide way (12) up and down, and one end, facing the front of the massage armchair, of the second slide way (13) exceeds one end, facing the front of the massage armchair, of the first slide way (12).

10. The dual track type massage chair with cooperative adjustment of forward and backward sliding and dumping angle according to claim 1, wherein: the first driving device (41) comprises a first expansion piece (411), and two ends of the first expansion piece (411) in the expansion direction are respectively hinged with the main body mounting frame (11) and the seat frame (2); the second driving device (42) comprises a second expansion piece (421), and two ends of the second expansion piece (421) in the expansion direction are hinged with the seat frame (2) and the backrest frame (3) respectively.

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