CN112006467B - Sofa extension device - Google Patents

Abstract

The present invention relates to a sofa telescopic device, comprising a base, a linkage mechanism, a leg mechanism, an armrest mechanism and a seat frame assembly, wherein the linkage mechanism and the armrest mechanism are connected to the base; the linkage mechanism comprises a side panel and a linkage assembly, wherein the seat frame assembly is connected to the side panel, and the linkage assembly is connected to the leg mechanism; the leg mechanism comprises a connecting rod assembly, a main footrest and an auxiliary footrest, wherein the connecting rod assembly is used to drive the main footrest and the auxiliary footrest to extend or contract, wherein the main footrest comprises a connecting surface for connecting to the main footrest board, and the length of the connecting surface is less than 12 cm; when the leg mechanism is contracted to the extreme position, the height of the highest point of the seat frame assembly from the ground is less than or equal to 28 cm, the height of the lowest point of the main footrest from the ground is not less than 10 cm, and the height of the auxiliary footrest from the ground is not less than 7 cm. The present invention has the characteristics of lowering the height of the sofa seat, increasing the height of the legs from the ground after contraction, and modern and simple appearance after soft packing.

Description

Sofa extension device

Technical Field

The invention relates to the field of sofas, and in particular to a sofa telescopic device.

Background Art

At present, with the improvement of domestic productivity and the development of social economy, people's living standards are getting higher and higher, and the requirements for furniture are getting higher and higher. Sofas, rocking chairs, chairs and other furniture can be seen everywhere. Some sofas can not only extend the footrest, but also adjust the seat height and backrest angle.

However, the existing sofa device has the following defects:

The sofa extension devices on the market have a relatively high overall seat height, which affects the comfort of the sofa. At the same time, when the sofa is extended, the leg extension height of the sofa is relatively low, the lying position cannot be completely relaxed, and the overall appearance of the sofa is bulky.

Summary of the invention

In view of the above problems in the prior art, the purpose of the present invention is to optimize the leg extension structure of the sofa, so that the leg mechanism can be extended in length and height, and the height from the ground can be increased after contraction, and at the same time, the armrest mechanism can be combined to change the overall appearance of the sofa, making it modern and simple in appearance.

In order to solve the above problems, the present invention provides a sofa extension device, comprising a base, a linkage mechanism and a leg mechanism, wherein the linkage mechanism is connected to the leg mechanism and the base respectively, and the linkage mechanism comprises a side plate and a linkage assembly;

The linkage assembly includes a first support member, a first bracket, a bracket connecting rod, a second bracket and a second support member, the first support member and the second support member are respectively rotatably connected to the side frame of the base, one end of the first bracket is connected to the first support member, the other end of the first bracket is connected to the side plate, one end of the bracket connecting rod is connected to the middle part of the first bracket, and the other end is connected to the second bracket, the second bracket is connected to the second support member, and the side plate is connected to the leg mechanism;

The leg mechanism comprises a connecting rod assembly, a main footrest and a secondary footrest, wherein the first rocker of the connecting rod assembly is connected to the first connecting rod, the second rocker, the second connecting rod, the third connecting rod and the fourth connecting rod of the connecting rod assembly are connected in sequence, the second connecting rod and the third connecting rod are respectively cross-connected with the first rocker and the first connecting rod, the first connecting rod and the fourth connecting rod are connected to the main footrest, the first rocker and the second rocker are respectively connected to the side plate, and the main footrest is connected to the secondary footrest;

When the leg mechanism is retracted to the extreme position, the height of the lowest point of the main footrest from the ground is not less than 10 cm, and the height of the lowest point of the auxiliary footrest from the ground is not less than 7 cm.

Further, the linkage assembly also includes a first linkage member, a second linkage member and a third linkage member;

The middle part of the second linkage is rotatably connected to the side plate, one end of the second linkage is connected to the first linkage, the first linkage is connected to the first support, the other end of the second linkage is connected to the third linkage, and the third linkage is connected to the leg mechanism.

Furthermore, the main footrest comprises a connection surface for connecting with a main footrest board, and the length of the connection surface is less than 12 cm.

Furthermore, a limit member is provided on the first bracket, and the limit member is provided between the side plate and the third linkage member, and the limit member is used to limit the position of the third linkage member relative to the side plate when the telescopic device is retracted to the limit position.

Furthermore, the linkage mechanism and the leg mechanism are each in two groups and are arranged opposite to each other along the center plane of the base. A first stabilizing rod is arranged between the two first supporting members of the linkage assembly, and a second stabilizing rod is arranged between the two second supporting members.

Furthermore, when the telescopic device is extended to the extreme position, the height of the auxiliary footrest from the ground is not less than 40 cm.

Furthermore, it also includes an armrest mechanism, which includes an armrest frame, an armrest connecting frame and an armrest support foot;

The armrest frame is connected to the base through an armrest connecting frame, and the armrest support leg is used to support the armrest frame. The armrest support leg is a tripod structure, and the height of the armrest support leg is not less than 10 cm.

Furthermore, it also includes a seat frame assembly, which is connected to the side panels. When the leg mechanism is retracted to the extreme position, the height of the highest point of the seat frame assembly from the ground is less than or equal to 28 cm.

Furthermore, it also includes a back mechanism, which is connected to the side panels. The first support member and the second support member rotate in the same direction, and the leg mechanism and the back mechanism are extended or contracted through the linkage mechanism.

Furthermore, it also includes a driving mechanism, which includes a driving connecting rod and a driving source;

The two ends of the driving connecting rod are respectively connected to the two leg mechanisms, and the middle part of the driving connecting rod is connected to the push rod of the driving source. The driving source is used to drive the leg mechanism to extend or contract, so that the telescopic device can be adjusted between the sitting position, the extended position and the lying position.

Due to the above technical solution, the present invention has the following beneficial effects:

(1) The connecting rod assembly of the present invention adopts a two-link and four-link cross-combination and a six-link telescopic structure, so that the length and height of the leg mechanism are increased, and the height of the footrest from the ground is increased after contraction. The present invention combines the leg mechanism and the linkage mechanism to reduce the height of the seat frame assembly, so that the overall seat height of the sofa is reduced. The sofa telescopic device has the characteristics of a low seat and high leg lift, and the stability of the device is increased, and the comfort is increased.

(2) The armrest support feet of the armrest mechanism of the present invention are arranged on the ground, and the armrest support feet are substantially at the same height as the main leg footrest after being retracted, thereby improving the concealment of the leg mechanism in the retracted state and making the overall appearance of the sofa modern and simple.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic structural diagram of a sofa extension device provided by an embodiment of the present invention;

2 is a connection diagram of the linkage mechanism of the telescopic device according to an embodiment of the present invention;

3 is a schematic diagram of an armrest mechanism of a telescopic device provided in an embodiment of the present invention;

FIG4 is a schematic structural diagram of the telescopic device in a sitting position according to an embodiment of the present invention;

5 is a schematic diagram of a telescopic device with a driving mechanism according to an embodiment of the present invention;

FIG6 is a schematic diagram of a sitting position of the sofa telescopic device of the present invention;

7 is a schematic diagram of the sofa telescopic device of the present invention in a leisure position;

FIG8 is a schematic diagram of the lying position of the sofa extension device of the present invention.

Among them, the accompanying drawings are marked as follows: 1-base, 11-side frame, 2-linkage mechanism, 3-leg mechanism, 4-armrest mechanism, 21-side panel, 22-linkage assembly, 31-connecting rod assembly, 32-main footrest, 321-main footrest, 322-connecting surface, 33-auxiliary footrest, 331-auxiliary footrest, 34-footrest connecting rod, 311-first rocker, 312-first connecting rod, 313-second rocker, 314-second connecting rod, 315-third connecting rod, 316- The fourth connecting rod, 41-armrest frame, 42-armrest connecting frame, 43-armrest support foot, 221-first linkage member, 222-second linkage member, 223-third linkage member, 23-first support member, 27-second support member, 24-first bracket, 26-second bracket, 25-bracket connecting rod, 241-limiting member, 51-first stabilizing rod, 52-second stabilizing rod, 6-seat frame assembly, 7-back mechanism, 8-driving mechanism, 81-driving connecting rod, 82-driving source.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

The "one embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In this embodiment, the direction of leg extension is defined as "front", and the direction of leg contraction is defined as "back".

In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Moreover, the terms "first", "second", etc. are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numerals used in this way are interchangeable where appropriate so that the embodiments of the invention described herein can be implemented in an order other than those illustrated or described herein.

Example

The embodiment of the present invention provides a sofa extension device, as shown in Figures 1-5, comprising: a base 1, a linkage mechanism 2, a leg mechanism 3, and a seat frame assembly 6, wherein the linkage mechanism 2 is connected to the base 1; the linkage mechanism 2 comprises a side plate 21 and a linkage assembly 22, wherein the linkage assembly 22 is used to change the relative position of the side plate 21 and the base 1, and the seat frame assembly 6 is connected to the side plate 21;

The linkage assembly 22 includes a first support member 23, a first bracket 24, a bracket connecting rod 25, a second bracket 26 and a second support member 27. The first support member 23 and the second support member 27 are respectively rotatably connected to the side frame 11 of the base 1. The side frame 11 includes a front end and a rear end. The first support member 23 is rotatably connected to the front end of the side frame 11, and the second support member 27 is rotatably connected to the rear end of the side frame 11. One end of the first bracket 24 is connected to the first support member 23, and the other end of the first bracket 24 is connected to the side plate 21. One end of the bracket connecting rod 25 is connected to the middle part of the first bracket 24, and the other end is connected to the second bracket 26. The second bracket 26 is connected to the second support member 27, and the side plate 21 is connected to the leg mechanism 3.

The linkage assembly 22 further includes a first linkage member 221, a second linkage member 222 and a third linkage member 223; the middle portion of the second linkage member 222 is rotatably connected to the side plate 21, one end of the second linkage member 222 is rotatably connected to the first linkage member 221, the first linkage member 221 is rotatably connected to the first support member 23, the other end of the second linkage member 222 is rotatably connected to the third linkage member 223, and the third linkage member 223 is rotatably connected to the second rocker 313 of the leg mechanism 3. When the leg mechanism is extended or contracted, the middle portion of the second linkage member 222 is rotatably connected to the side plate, one end of the second linkage member rotates forward, and the other end rotates backward.

Specifically, a limiting member 241 is disposed on the first bracket 24, and the limiting member 241 is disposed between the side plate 21 and the third linkage member 223. The limiting member 241 is used to limit the position of the third linkage member 223 relative to the side plate 21 when the telescopic device is retracted to the limit position.

Specifically, in some embodiments, the first bracket 24 is a V-shaped structure, the middle of the V-shaped structure is connected to the bracket connecting rod, and the two ends are respectively connected to the first support member and the side plate. The bracket connecting rod 25 is a straight sheet structure. The optimization of the structural shape and connection angle of the parts in the linkage assembly 22 improves the structural strength of the linkage mechanism and reduces the height of the side plate relative to the base.

The leg mechanism 3 includes a connecting rod assembly 31, a main footrest 32 and an auxiliary footrest 33, the first rocker 311 of the connecting rod assembly 31 is connected to the first connecting rod 312, the second rocker 313, the second connecting rod 314, the third connecting rod 315 and the fourth connecting rod 316 of the connecting rod assembly 31 are connected in sequence, the second connecting rod 314 and the third connecting rod 315 are respectively cross-connected with the first rocker 311 and the first connecting rod 312 to form a quadrilateral structure, the first connecting rod 312 and the fourth connecting rod 316 are connected to the main footrest 32, the first rocker 311 and the second rocker 313 are respectively connected to the side plate 21, the main footrest 32 is connected to the auxiliary footrest 33, the main footrest 32 includes a connecting surface 322 for connecting with the main footrest board 321, and the length of the connecting surface 322 is less than 12 cm;

Specifically, the main footrest 32 is connected to the main footrest board 321 through the connecting surface 322 and the fastener. The length of the connecting surface 322 is less than 12 cm, and the length direction of the connecting surface is consistent with the width direction of the main footrest board 321. Preferably, the length of the connecting surface 322 can be 8 cm, 9 cm, 10 cm or 12 cm, and the width of the main footrest board 321 is also less than 12 cm.

The auxiliary footrest 33 is connected to the auxiliary footrest plate 331, wherein a footrest link 34 is further provided between the main footrest 32 and the auxiliary footrest 33, one end of the footrest link 34 is connected to the fourth link 316, and the other end of the footrest link 34 is connected to the middle of the auxiliary footrest 33. The link assembly 31 drives the auxiliary footrest 33 and the auxiliary footrest plate 331 to extend or fold relative to the main footrest 321 through the footrest link 34.

Specifically, when the leg mechanism 3 is retracted to the extreme position, the height of the lowest point of the main footrest 32 from the ground is not less than 10 cm, and the height of the lowest point of the auxiliary footrest 33 from the ground is not less than 7 cm, that is, the height of the connecting surface between the auxiliary footrest and the auxiliary footrest board is not less than 7 cm from the ground.

The armrest mechanism 4 includes an armrest frame 41, an armrest connecting frame 42 and an armrest support leg 43. The armrest frame 41 is connected to the base 1 through the armrest connecting frame 42. The armrest support leg 43 is used to support the armrest frame 41. The height of the armrest support leg 43 is not less than 10 cm.

Preferably, in the embodiment of the present invention, the height of the armrest bracket 24 is substantially the same as the height of the lower edge of the main footrest 32 from the ground when the leg mechanism 3 is retracted to the limit position, which is 13 cm from the ground. When retracted to the limit position, the height of the auxiliary footrest 33 from the ground is 9 cm. In some embodiments, the armrest support foot can be a triangular support structure, a cylindrical support foot or other shapes.

Specifically, when the telescopic device is extended to the extreme position, the height of the auxiliary footrest 33 from the ground is not less than 40 cm. Preferably, the height of the auxiliary footrest 33 from the ground can reach 25 cm, 26 cm, 50 cm or 55 cm.

Specifically, the linkage mechanism 2 and the leg mechanism 3 are both in two groups and are symmetrically arranged along the central plane of the base 1. A first stabilizing rod 51 is arranged between the two first supporting members 23 of the linkage mechanism 2, and a second stabilizing rod 52 is arranged between the two second supporting members 27. The first stabilizing rod and the second stabilizing rod are used to increase the structural stability and strength of the telescopic device and prevent torsional deformation.

Specifically, the base includes two side frames and a rear frame connected to the two side frames, and two linkage mechanisms are respectively connected to the two side frames.

The telescopic device of the present application also includes a driving mechanism 8, which includes a driving connecting rod 81 and a driving source 82; the two ends of the driving connecting rod 81 are respectively connected to the two leg mechanisms 3, the driving source 82 is arranged between the driving connecting rod and the rear frame, and the middle part of the driving connecting rod 81 is connected to the push rod of the driving source 82, and the driving source 82 is used to drive the leg mechanisms 3 to extend or contract, so that the telescopic device can be adjusted between a sitting position, a stretched position and a lying position.

Specifically, it also includes a seat frame assembly 6, which is connected to the two side panels 21. The seat frame assembly 6 is used to support the soft padding of the sofa seat. When the leg mechanism 3 is retracted to the extreme position, the height of the highest point of the seat frame assembly 6 from the ground is less than or equal to 28 cm. The seat frame assembly and the side panels 21 are tilted relative to the base, wherein the height of the seat frame assembly is higher at one end close to the leg mechanism. Preferably, when the leg mechanism 3 is retracted to the extreme position, the height of the highest point of the seat frame assembly 6 from the ground is 26 cm. The existing functional sofas are generally higher than 50 cm. After the seat frame assembly of this embodiment is soft-padded, the seat height of the sofa can reach 24 cm, which reduces the seat height and improves comfort.

Specifically, it also includes: a back mechanism 7, the back mechanism 7 is connected to the side plate 21,

The first support member 23 and the second support member 27 rotate in the same direction, and the leg mechanism 3 and the back mechanism 7 are extended or contracted through the linkage mechanism 2. Specifically, when the leg mechanism 3 and the back mechanism 7 are adjusted to the extended position, the backrest member of the back mechanism 7 is adjusted backward and downward relative to the linkage mechanism 2. The backrest mechanism 7 includes a back mounting member and a back linkage rod, the back mounting member is rotatably connected to the side panel 21 and the back linkage rod respectively, and the two ends of the back linkage rod are rotatably connected to the back mounting member and the second bracket 26 respectively, the back linkage rod is used to link and control the rotation angle of the back mounting member, and the back mounting member is used to connect with the backrest frame of the sofa.

The connecting rod assembly of the present invention adopts a two-link and four-link cross-combination and a six-link telescopic structure, so that the length and height of the leg mechanism are increased, and the height of the footrest from the ground is increased after retraction. The present invention combines the leg mechanism and the linkage mechanism to reduce the height of the seat frame assembly, so that the overall seat height of the sofa is reduced. The sofa telescopic device has the characteristics of a low seat and high leg lift, and the stability of the device is increased, and the comfort is increased. The armrest support feet of the armrest mechanism of the present invention are set on the ground, and the height of the armrest support feet and the main leg rest are basically the same after retraction, which improves the concealment of the leg mechanism in the retracted state and makes the overall appearance of the sofa modern and simple.

The telescopic device of the present invention can realize three position adjustments of sitting, leisure and lying. As shown in Figures 6-8, there are schematic diagrams of the telescopic device in three positions. In order to prevent pinching and protect the leg mechanism structure, a protective plate can be set on the outside of the leg connecting rod assembly. In the sitting state, the leg mechanism shrinks to the extreme position below the seat frame assembly, and the backrest frame is basically perpendicular to the seat frame assembly; when the telescopic device is adjusted from the sitting position to the leisure position, the driving device drives the connecting rod assembly to extend forward and upward relative to the seat frame assembly, and at the same time drives the linkage mechanism, the seat frame assembly and the backrest mechanism to move forward relative to the base; when it is adjusted from the leisure position to the lying state, the leg mechanism continues to lift upward, driving the side panels and the seat frame assembly to rotate upward by a certain angle, so that the backrest mechanism rotates backward and extends relative to the base to achieve the lying position. In the lying position, the height of the user's feet will be higher than the head. Specifically, when adjusting from a sitting position to a lying position, the user is first adjusted to a leisure position, and then the driving connecting rod is pushed to continue rotating to adjust to the lying position. The adjustment process is continuous. On the contrary, when adjusting from a lying position to a sitting position, the user is first adjusted to a leisure position and then to a sitting position.

In some embodiments, the sofa extension device of the present invention can also be combined into a row of extension device structures by using a splicing frame to form a row of sofas after being soft-covered.

The above description has fully disclosed the specific embodiments of the present invention. It should be pointed out that any changes made by those skilled in the art to the specific embodiments of the present invention do not deviate from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited to the above specific embodiments.

Claims (10)

1. The sofa telescoping device is characterized by comprising a base (1), a linkage mechanism (2) and a leg mechanism (3), wherein the linkage mechanism (2) is respectively connected with the leg mechanism (3) and the base (1), and the linkage mechanism (2) comprises a side plate (21) and a linkage assembly (22);

the linkage assembly (22) comprises a first supporting piece (23), a first bracket (24), a bracket connecting rod (25), a second bracket (26) and a second supporting piece (27), wherein the first supporting piece (23) and the second supporting piece (27) are respectively connected with a side frame (11) of the base (1) in a rotating mode, one end of the first bracket (24) is connected with the first supporting piece (23), the other end of the first bracket (24) is connected with the side plate (21), one end of the bracket connecting rod (25) is connected with the middle of the first bracket (24), the other end of the bracket connecting rod is connected with the second bracket (26), the second bracket (26) is connected with the second supporting piece (27), and the side plate (21) is connected with the leg mechanism (3);

The leg mechanism (3) comprises a connecting rod assembly (31), a main foot rest (32) and an auxiliary foot rest (33), a first rocker (311) and a first connecting rod (312) of the connecting rod assembly (31) are connected, a second rocker (313), a second connecting rod (314), a third connecting rod (315) and a fourth connecting rod (316) of the connecting rod assembly (31) are sequentially connected, the second connecting rod (314) and the third connecting rod (315) are respectively in cross connection with the first rocker (311) and the first connecting rod (312), the first connecting rod (312) and the fourth connecting rod (316) are connected with the main foot rest (32), the first rocker (311) and the second rocker (313) are respectively connected with the side plate (21), and the main foot rest (32) is connected with the auxiliary foot rest (33);

When the leg mechanism (3) is contracted to the limit position, the height of the lowest point of the main foot rest (32) from the ground is not less than 10cm, and the height of the lowest point of the auxiliary foot rest (33) from the ground is not less than 7cm.

2. The sofa telescoping device of claim 1, wherein said linkage assembly (22) further comprises a first linkage (221), a second linkage (222), and a third linkage (223);

The middle part of second interlock spare (222) with curb plate (21) rotate and be connected, the one end of second interlock spare (222) with first interlock spare (221) are connected, first interlock spare (221) with first support piece (23) are connected, the other end of second interlock spare (222) with third interlock spare (223) are connected, third interlock spare (223) with shank mechanism (3).

3. A sofa telescoping device according to claim 1, wherein said main foot rest (32) comprises a connecting surface (322) for connecting with a main foot rest (321), said connecting surface (322) having a length of less than 12cm.

4. A sofa telescoping device according to claim 2, wherein a limiting member (241) is arranged on the first bracket (24), wherein the limiting member (241) is arranged between the side plate (21) and the third linkage member (223), and wherein the limiting member (241) is used for limiting the position of the third linkage member (223) relative to the side plate (21) when the telescoping device is contracted to a limit position.

5. The sofa telescoping device according to claim 1, wherein the linkage mechanism (2) and the leg mechanism (3) are two groups and are oppositely arranged along the central plane of the base (1), a first stabilizer bar (51) is arranged between the two first supporting pieces (23) of the linkage assembly (22), and a second stabilizer bar (52) is arranged between the two second supporting pieces (27).

6. A sofa telescoping device according to claim 1, wherein the height of the secondary foot rest (33) from the ground is not less than 40cm when the telescoping device is extended to the extreme position.

7. The sofa telescoping device according to claim 1, further comprising a armrest mechanism (4), said armrest mechanism (4) comprising an armrest frame (41), an armrest connection frame (42) and armrest legs (43);

The handrail frame (41) is connected with the base (1) through a handrail connecting frame (42), handrail support legs (43) are used for supporting the handrail frame (41), the handrail support legs (43) are of a tripod support structure, and the height of the handrail support legs (43) is not less than 10cm.

8. The sofa telescoping device according to claim 1, further comprising a seat frame assembly (6), said seat frame assembly (6) being connected to said side panels (21), the highest point of said seat frame assembly (6) being at a height of 28cm or less from the ground when said leg mechanism (3) is retracted to a limit position.

9. A sofa telescoping device according to claim 1, further comprising a back mechanism (7), said back mechanism (7) being connected to said side plate (21), said first support (23) and second support (27) being rotated in the same direction, said leg mechanism (3) and said back mechanism (7) being brought into an extended or contracted state by said linkage (2).

10. A sofa telescoping device according to claim 1, further comprising a drive mechanism (8), said drive mechanism (8) comprising a drive link (81) and a drive source (82);

The two ends of the driving connecting rod (81) are respectively connected with the two leg mechanisms (3), the middle part of the driving connecting rod (81) is connected with a push rod of the driving source (82), and the driving source (82) is used for driving the leg mechanisms (3) to extend or retract so that the telescopic device can be adjusted among sitting, extending and lying positions.