Supporting telescopic frame structure for sofa bed

Abstract

The invention discloses a supporting telescopic frame structure for a sofa bed, which comprises a bottom frame for supporting the sofa bed and a seat frame for fixing a sofa cushion, and further comprises a backrest mounting and supporting assembly for mounting a sofa backrest and a linkage telescopic assembly for driving and guiding the bottom frame and the seat frame to generate relative telescopic motion. By the adoption of the structure, the small-space use scene requirement of a living room or an office can be greatly met, meanwhile, more stable supporting and guiding are provided for unfolding and folding of the sofa bed, and a guarantee is provided for use comfort of the sofa bed.

Description

Technical Field

[0001] This invention belongs to the field of furniture, and specifically relates to a support telescopic frame structure for a sofa bed. Background Technology

[0002] A sofa bed is a piece of furniture that combines the functions of a sofa and a bed. It offers flexible usage options within limited spaces, making it suitable for homes or offices with limited space. It can be used as a sofa during the day and easily converted into a bed at night, providing additional sleeping space. Due to its high practicality and adaptability to different spaces, it is gaining increasing popularity. The core structure of a sofa bed is mainly a telescopic mechanism, used to expand and retract the backrest and seat cushions, thus switching between sofa and bed modes. Existing telescopic mechanisms vary in structure, and while they generally meet the telescopic requirements, they often have various problems, as follows: First, existing telescopic structures, while ensuring that the telescopic function is not affected, must also ensure that the telescopic structure does not affect the layout of the sofa backrest and seat cushions. To this end, many telescopic structures often design the rotating joint position as a large arc-shaped bend (see patent number 202420864948.0, entitled Integrated Detachable Flat-Lying Function Frame). The part of the seat cushion near the sofa backrest is tucked into this arc-shaped bend, so that there are no excessive gaps between the seat cushion and the backrest, whether the sofa is unfolded or folded, thus avoiding affecting the aesthetics and usability. However, this design presents a problem. When the sofa backrest changes from a vertical to a horizontal position, the horizontal travel of the extension mechanism (i.e., the distance the sofa cushions move away from the sofa backrest) often exceeds 60cm. Typically, the distance between the sofa and coffee table in the living room is 50-60cm, so existing sofa beds often require the coffee table to be moved in advance to allow sufficient space and prevent collisions during unfolding. This means the coffee table needs to be moved back and forth every time the sofa is unfolded or folded, causing inconvenience. Furthermore, if the coffee table isn't moved before unfolding, someone sitting on the sofa during unfolding could be injured by the sofa and coffee table, potentially causing their legs to be crushed. This is clearly a significant safety hazard.

[0003] Second, existing sofa telescopic structures often rely on traditional sliding rails, roller grooves, and other structures to achieve the sliding between the backrest and the seat cushion. However, whether it is a traditional sliding rail or a roller groove, it requires high precision during installation, has high installation requirements, and is prone to problems such as jamming and noise during later use, affecting the normal use and experience of the sofa bed.

[0004] III. Connection and Fixing Issues Between the Telescopic Frame and the Sofa Backrest. Existing telescopic frames are connected to the sofa backrest via connecting plates (e.g., patent number 202420864948.0, named "Integrated Detachable Reclining Function Frame"). The connecting plates are welded and fixed to the telescopic frame with pre-drilled holes. Before installing the sofa backrest onto the telescopic frame, corresponding holes for the connecting plates are drilled in the side frame (wooden blocks) of the sofa backrest. However, because the mounting holes on the sofa backrest are drilled temporarily on-site, deviations in drilling distance and height often lead to difficulties in installing the sofa backrest, resulting in low installation efficiency. In some cases, incorrect drilling positions may prevent re-drilling, necessitating the replacement of parts of the frame, severely impacting installation efficiency and increasing installation costs. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a support telescopic frame structure for sofa beds, which solves the problem that the telescopic stroke of existing sofa bed telescopic structures is too large, which can easily cause the sofa to collide with the coffee table or even cause injury. At the same time, it also solves the problems of poor sliding and low installation efficiency of existing sofa bed telescopic structures.

[0006] The technical solution adopted by the present invention to solve the above problems is: A support telescopic frame structure for a sofa bed includes a base frame for supporting the sofa bed and a seat frame for fixing the sofa cushions, as well as a backrest mounting support assembly for mounting the sofa back and a linkage telescopic assembly for driving and guiding the relative telescopic movement between the base frame and the seat frame. The base frame is equipped with support legs to support the weight of the entire sofa bed, and its side near the backrest has an opening design. The seat frame and the bottom frame are slidably connected. Driven by the linkage telescopic component, the seat frame can extend and retract into the internal space of the bottom frame through the opening on the bottom frame, so as to realize the unfolding and folding of the sofa bed. The linkage telescopic assembly includes an electric push rod as a power source, a linkage deformation mechanism for transmitting motion and changing the posture of the sofa backrest, and a sliding guide mechanism for constraining the movement path of the seat frame.

[0007] Furthermore, as a preferred technical solution, the base frame includes a rectangular base frame body formed by welding or fastening four fixed support legs, two parallel side connecting rods, and a back connecting rod; at least one transverse fixing rod is fixed between the side connecting rods on both sides of the rectangular base frame body; and two guide support rods are fixed parallel to the transverse fixing rod and the back connecting rod.

[0008] Furthermore, as a preferred technical solution, the seat frame includes a seat frame body, and the lower part of the seat frame body away from the sofa back is provided with two sliding support feet with pulleys. The side of the seat frame body closer to the sofa back is slidably connected to the guide support rod of the bottom frame 1 through the sliding guide mechanism.

[0009] Furthermore, as a preferred technical solution, the cylinder fixed end of the electric push rod is hinged or fixed to the transverse fixed rod, and the push rod extension end of the electric push rod is hinged to the bottom or side of the seat frame.

[0010] Furthermore, as a preferred technical solution, the linkage deformation mechanism includes a support column, a first link, and a second link; The lower end of the support column is fixedly connected to the base frame, and the upper end of the support column extends beyond the top surface of the base frame. The first connecting rod is formed by connecting the front section and the rear section and has an overall acute-angle bent structure. The upper end of the front section of the first connecting rod is hinged to the upper end of the support column to form the first hinge point. The first connecting rod is located on the outside of the support column. The upper end of the second connecting rod is hinged to the upper end of the rear section of the first connecting rod to form a second hinge point; the lower end of the second connecting rod is hinged to the guide support rod or an independent hinge seat fixed on the bottom frame to form a third hinge point. The backrest mounting support assembly is fixedly connected to the upper part of the rear section of the first link or the upper part of the second link.

[0011] Furthermore, as a preferred technical solution, the sliding guide mechanism includes a guide support rod and a double guide wheel that matches the guide support rod. The double guide wheel is fixed to the lower part of the support column or the bottom of the seat frame by a wheel frame. The rod body of the guide support rod is embedded between the upper and lower rollers of the double guide wheel to form a rolling friction fit.

[0012] Furthermore, as a preferred technical solution, the cross-section of the guide support rod is circular or rectangular, and the roller groove of the double guide wheel matches it.

[0013] Furthermore, as a preferred technical solution, the support pole is L-shaped, with its vertical section fixedly connected to the seat frame and its horizontal section extending towards the back of the sofa. The double guide wheels are fixedly installed below the end of the horizontal section of the support pole.

[0014] Furthermore, as a preferred technical solution, the backrest mounting support assembly includes a positioning mounting piece for connecting the backrest frame and a locking pin. The locking pin includes a male pin and a female pin. The positioning mounting piece and the male pin are respectively provided with matching screw holes. The female pin is fixed to the upper part of the rear section of the first connecting rod or the upper part of the second connecting rod by a fixing seat.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses a linkage deformation mechanism consisting of a support rod, a first link and a second link to realize the unfolding and folding of the seat frame and the bottom frame. Since the upper end of the support rod is higher than the top surface of the seat frame, the distance between the first hinge point A and the second hinge point B is shorter than that of the existing deformation structure, and the stroke of the electric push rod is shorter than that of the existing structure. For living rooms or offices with limited space, the sofa bed can be easily unfolded without moving the coffee table in advance, and there is no need to worry about the safety problem caused by the legs being pinched. It can better adapt to the use scenario of small space.

[0016] (2) The present invention adopts a sliding guide mechanism consisting of a guide support rod, double guide wheels and a support rod. The guide support rod enhances the strength of the bottom frame and provides stable guide support for the movement of the seat frame. The double guide wheels provide smoother and more reliable sliding for the telescopic movement of the seat frame. Compared with the traditional telescopic structure that sets the slide groove and similar structure on the side of the frame, the support rod and guide support rod of the present invention provide stronger and more reliable support, and the sliding guide is more reliable and easier to install.

[0017] (3) By setting the support upright in an L-shape, the vertical section of which is fixedly connected to the seat frame and the horizontal section of which extends towards the back of the sofa, and the double guide wheels are fixedly installed below the end of the horizontal section of the support upright, the support point of the seat frame near the back of the sofa is located outside the seat frame, so that the center of gravity of the seat frame is not too far away from the side where the fixed support foot is set, and the fixed support foot is prevented from leaving the ground when the sofa bed is unfolded, thereby ensuring that the seat frame is always stably supported and enhancing the comfort of the sofa bed.

[0018] (4) The present invention uses positioning mounting pieces and pins to realize the installation between the sofa back and the telescopic frame. During installation, it is only necessary to first install the two positioning mounting pieces on the frame (a long wooden block) of the sofa back at a preset distance, then fix the male pin to the positioning mounting piece with screws, and finally insert the male pin on the sofa back into the female pin, thus completing the installation connection between the sofa back and the telescopic support bracket. The whole installation process is quick and efficient. Compared with the existing side installation, the present invention has lower installation accuracy requirements and a higher fault tolerance rate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention when folded into a sofa; Figure 2 This is a schematic diagram of the overall structure of the present invention when unfolded into a bed; Figure 3 This is a schematic diagram showing the positional relationship between the electric push rod, the connecting rod deformation mechanism, and the sliding guide mechanism when the device is retracted. Figure 4 This is a schematic diagram showing the positional relationship between the electric push rod, the connecting rod deformation mechanism, and the sliding guide mechanism when the present invention is deployed. Figure 5 This is a side view of the invention when it is folded up; Figure 6 This is a side view of the invention when unfolded; Figure 7 This is a schematic diagram showing the connection relationship between the sofa backrest and the mounting support assembly of the present invention; Figure 8 This is a schematic diagram showing the positional relationship between the sofa backrest, the mounting support components, and the telescopic frame of the present invention. Figure 9 This is a schematic diagram of the installation structure of an existing sofa backrest and telescopic bracket.

[0020] The corresponding component names in the attached diagram are as follows: 1. Base frame, 2. Seat frame, 3. Electric push rod, 11. Fixed support foot, 12. Side connecting rod, 13. Back connecting rod, 14. Lateral fixing rod, 15. Guide support rod, 16. Backrest, 17. Seat cushion, 21. Sliding support foot, 31. Cylinder fixed end, 41. Support upright, 42. First connecting rod, 43. Second connecting rod, 51. Double guide wheel, 52. Wheel frame, 61. Positioning mounting plate, 62. Pin, 421. Front section, 422. Rear section, 621. Male pin, 622. Female pin, 623. Female pin fixing seat, A. First hinge point, B. Second hinge point, C. Third hinge point. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Example

[0022] like Figure 1-6 As shown in the figure, the support telescopic frame structure for a sofa bed in this embodiment includes a base frame 1 for supporting the sofa bed and a seat frame 2 for fixing the sofa cushion. It also includes a backrest mounting support assembly for mounting the sofa back and a linkage telescopic assembly for driving and guiding the base frame 1 and the seat frame 2 to produce relative telescopic movement.

[0023] In this embodiment, the base frame 1 is equipped with support legs to support the weight of the entire sofa bed, and the side near the backrest has an opening design; the seat frame 2 is slidably connected to the base frame 1, and the seat frame 2 can extend and retract into the internal space of the base frame 1 through the opening on the base frame 1 under the drive of the linkage telescopic component, so as to realize the unfolding and folding of the sofa bed.

[0024] The linkage telescopic assembly in this embodiment includes an electric push rod 3 as a power source, a linkage deformation mechanism for transmitting motion and changing the posture of the sofa backrest, and a sliding guide mechanism for constraining the movement path of the seat frame 2.

[0025] Specifically, such as Figure 1 , Figure 2 As shown, the base frame 1 of this embodiment includes a rectangular base frame body formed by welding or fastening four fixed support legs 11, two parallel side connecting rods 12 and a back connecting rod 13; at least one transverse fixing rod 14 is fixed between the side connecting rods 12 on both sides of the rectangular base frame body, and two guide support rods 15 are fixed parallel to the transverse fixing rod 14 and the back connecting rod 13.

[0026] like Figure 1 , Figure 2 As shown, the seat frame 2 in this embodiment includes a seat frame body. Two sliding support feet 21 with pulleys are provided on the lower side of the seat frame body away from the sofa back. The side of the seat frame body close to the sofa back is slidably connected to the guide support rod 15 of the bottom frame 1 through a sliding guide mechanism.

[0027] In this embodiment, the cylinder fixed end 31 of the electric push rod 3 is hinged or fixed to the transverse fixed rod 14, and the push rod extension end of the electric push rod 3 is hinged to the bottom or side of the seat frame 2. Under the action of the electric push rod 3, the seat frame 2 can extend and retract into the internal space of the bottom frame 1, that is, the sofa bed can unfold and retract.

[0028] It should be noted that electric linear actuators are existing technology. For electric linear actuators, the necessary controllers, control switches, or wireless receiving modules (not shown in the figure) are common knowledge to those skilled in the art. Therefore, the specific structure, connection relationship, and working principle of electric linear actuators will not be described in detail.

[0029] like Figure 3 , Figure 4 As shown, the linkage deformation mechanism of this embodiment includes a support rod 41, a first link 42 and a second link 43. The lower end of the support rod 41 is fixedly connected to the base frame 2, and the upper end of the support rod 41 extends beyond the top surface of the base frame 2. The first connecting rod 42 is formed by connecting the front section 421 and the rear section 422 and has an overall acute angle bent structure. The upper end of the front section 421 of the first connecting rod 42 is hinged to the upper end of the support rod 41 to form the first hinge point A. The first connecting rod 42 is located on the outside of the support rod 41. The upper end of the second link 43 is hinged to the upper end of the rear section 422 of the first link 42, forming the second hinge point B; the lower end of the second link 43 is hinged to the guide support rod 15 or an independent hinge seat fixed on the bottom frame 1, forming the third hinge point C. The backrest mounting support assembly is fixedly connected to the upper part of the rear section 422 of the first link 42 or the upper part of the second link 43.

[0030] In this embodiment, when the sofa bed is used as a sofa, the support telescopic frame is in a retracted state. At this time, the rear section 422 of the first connecting rod 42 and the second connecting rod 43 are both in a vertical state. Under the combined action of the support upright 41, the first connecting rod 42, and the second connecting rod 43, the sofa back is well supported. Figure 1 , Figure 5 As shown; when the sofa bed needs to be converted from a sofa to a bed, the electric push rod 3 is activated. The telescopic end of the electric push rod 3 pulls the seat frame 2 away from the sofa back. The second connecting rod 43 gradually changes from a vertical state to an inclined state towards the seat frame. At the same time, the front part 421 of the first connecting rod 42 gradually changes from an inclined state to a vertical state. When the front part 421 of the first connecting rod 42 becomes vertical, the electric push rod 3 stops moving. At this time, the seat frame 2 and the bottom frame 1 are fully extended, as shown. Figure 2 , Figure 6 As shown, at this point, the sofa backrest is in a horizontal position, and the sofa bed has completed its transformation from a sofa to a bed. Similarly, when it is necessary to transform the sofa bed from a bed to a sofa, the electric push rod 3 is activated. The telescopic end of the electric push rod 3 pulls the seat frame 2 towards the sofa backrest, and the second connecting rod 43 gradually changes from an inclined state to a vertical state. At the same time, the rear part 422 of the first connecting rod 43 also gradually changes from an inclined state to a vertical state. When the second connecting rod 43 becomes vertical, the electric push rod 3 stops moving, and at this time, the seat frame 2 and the bottom frame 1 are fully retracted, as shown. Figure 1 , Figure 5 As shown, the sofa bed has now been transformed from a bed into a sofa.

[0031] Existing telescopic designs (such as the one with patent number 202420864948.0, named "Integrated Detachable Flat-Lying Function Frame") often place the first hinge point on the seat frame. Under standard sofa dimensions, the distance from the hinge point formed by the second deformable swing arm and the seat frame to the hinge point between the first and second deformable swing arms is relatively large. In addition, the second deformable swing arm is made into a large arc-shaped structure to embed the sofa cushion, which means that the electric push rod must travel 60-70cm (this is the actual measured data of related products on the market) to achieve full unfolding of the sofa bed (backrest fully flattened). For the conventional sofa and coffee table layout, the unfolding and folding of such sofa beds will bring great inconvenience and may also pose safety hazards (leg pinching). This invention employs a linkage deformation mechanism consisting of a support rod 41, a first connecting rod 42, and a second connecting rod 43 to achieve the unfolding and retraction of the seat frame 2 and the bottom frame 1. Since the upper end of the support rod 41 is higher than the top surface of the seat frame 2, the distance between the first hinge point A and the second hinge point B is shorter than that of existing deformation structures. The direct effect is that when the sofa bed is fully unfolded (the backrest is fully flattened), the stroke of the electric push rod 3 is shorter, with a measured stroke of less than 40cm. For living rooms or offices with limited space, the sofa bed can be easily unfolded without having to move the coffee table in advance, and there is no need to worry about the safety issues caused by leg pinching, making it better suited for small space usage scenarios.

[0032] like Figure 3 , Figure 4 As shown, the sliding guide mechanism of this embodiment includes a guide support rod 15 and double guide wheels 51 that match the guide support rod 15. The double guide wheels 51 are fixed to the lower part of the support rod 41 or the bottom of the seat frame 2 by a wheel frame 52. The rod body of the guide support rod 15 is embedded between the upper and lower rollers of the double guide wheels 51 to form a rolling friction fit. In this embodiment, the cross-section of the guide support rod 15 is circular or rectangular, and the roller groove of the double guide wheels 41 matches it. This embodiment uses a sliding guide mechanism composed of the guide support rod 15, double guide wheels 51, and support rod 41. The guide support rod 15 enhances the frame strength of the bottom frame 1 while providing guiding support for the movement of the seat frame 2. The double guide wheels 51 provide smoother and more reliable sliding for the telescopic movement of the seat frame 2. Compared with the traditional telescopic structure that sets the sliding groove and similar structure on the side of the frame, the support rod and guide support rod of this invention provide stronger and more reliable support, and the sliding guidance is more reliable and easier to install.

[0033] like Figure 4As shown, the support rod 41 in this embodiment is L-shaped, with its vertical section 411 fixedly connected to the seat frame 2, and its horizontal section 412 extending towards the sofa back. Double guide wheels 45 are fixedly installed below the end of the horizontal section 412 of the support rod 42. This design ensures that the support point of the seat frame 2 near the sofa back is located outside the seat frame 2, preventing the center of gravity of the seat frame 2 from deviating too far from the side where the fixed support legs 11 are located. This prevents the fixed support legs 11 from leaving the ground when the sofa bed is in the unfolded state, thus ensuring that the seat frame is always stably supported and enhancing the comfort of the sofa bed.

[0034] like Figure 4 As shown, the backrest mounting support assembly of this embodiment includes a positioning mounting piece 61 for connecting the backrest frame and a locking pin 62. The locking pin 62 includes a male pin 621 and a female pin 622. The positioning mounting piece 61 and the male pin 621 are respectively provided with matching screw holes. The female pin 622 is fixed to the upper end of the rear section 422 of the first connecting rod 42 or the upper end of the second connecting rod 43 through a female fixing seat 623. Taking a standard sofa as an example, Figure 7 , Figure 8 As shown, during installation, simply install the two positioning mounting pieces 61 at a preset distance onto the frame (a long wooden block) of the sofa backrest 16. Then, fix the male pin 621 to the positioning mounting pieces 61 with screws. Finally, insert the male pin 621 on the sofa backrest into the female pin 622. This completes the installation connection between the sofa backrest and the telescopic support bracket. The entire installation process is quick and efficient, and can be completed in one go. Existing installation methods, such as... Figure 9 As shown, the left image shows the telescopic frame connected with the mounting parts, and the right image shows the sofa backrest with pre-set matching mounting parts and fixed with screws. This installation method requires high precision and is difficult to align perfectly on the first try. It is also easy to encounter problems such as misaligned screw holes, making installation impossible.

[0035] As described above, the present invention can be implemented well.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A telescopic support frame structure for a sofa bed, comprising a base frame (1) for supporting the sofa bed and a seat frame (2) for fixing the sofa cushion, characterized in that: It also includes a backrest mounting support assembly for mounting the sofa backrest and a linkage telescopic assembly for driving and guiding the bottom frame (1) and the seat frame (2) to produce relative telescopic movement. The bottom frame (1) is equipped with support legs and is used to support the weight of the entire sofa bed. The side of the frame near the backrest is designed with an opening. The seat frame (2) and the bottom frame (1) are slidably connected. Under the drive of the linkage telescopic component, the seat frame (2) can extend and retract into the internal space of the bottom frame (1) through the opening on the bottom frame (1) to realize the unfolding and folding of the sofa bed. The linkage telescopic assembly includes an electric push rod (3) as a power source, a linkage deformation mechanism for transmitting motion and changing the posture of the sofa backrest, and a sliding guide mechanism for constraining the movement path of the seat frame (2).

2. The telescopic support frame structure for a sofa bed according to claim 1, characterized in that: The bottom frame (1) includes a rectangular bottom frame body formed by welding or fastening four fixed support legs (11), two parallel side connecting rods (12) and a back connecting rod (13); at least one transverse fixing rod (14) is fixed between the side connecting rods (12) on both sides of the rectangular bottom frame body; two guide support rods (15) are fixed parallel between the transverse fixing rod (14) and the back connecting rod (13).

3. The telescopic support frame structure for a sofa bed according to claim 2, characterized in that: The seat frame (2) includes a seat frame body. The seat frame body is provided with two sliding support feet (21) with pulleys on the side away from the back of the sofa. The side of the seat frame body close to the back of the sofa is slidably connected to the guide support rod (15) of the bottom frame (1) through the sliding guide mechanism.

4. A telescopic support frame structure for a sofa bed according to claim 2 or 3, characterized in that: The cylinder fixed end (31) of the electric push rod (3) is hinged or fixed to the transverse fixed rod (14), and the push rod extension end of the electric push rod (3) is hinged to the bottom or side of the seat frame (2).

5. A telescopic support frame structure for a sofa bed according to claim 2 or 3, characterized in that: The linkage deformation mechanism includes a support rod (41), a first link (42), and a second link (43). The lower end of the support rod (41) is fixedly connected to the seat frame (2), and the upper end of the support rod (41) extends above the top surface of the seat frame (2). The first connecting rod (42) is formed by connecting the front section (421) and the rear section (422) and has an overall acute angle bent structure. The upper end of the front section (421) of the first connecting rod (43) is hinged to the upper end of the support rod (41) to form the first hinge point (A). The first connecting rod (42) is located on the outside of the support rod (41). The upper end of the second link (43) is hinged to the upper end of the rear section (422) of the first link (42) to form a second hinge point (B); the lower end of the second link (43) is hinged to the guide support rod (15) or an independent hinge seat fixed on the bottom frame (1) to form a third hinge point (C). The backrest mounting support assembly is fixedly connected to the upper part of the rear section (422) of the first link (42) or the upper part of the second link (43).

6. A telescopic support frame structure for a sofa bed according to claim 5, characterized in that: The sliding guide mechanism includes a guide support rod (15) and a double guide wheel (51) that matches the guide support rod (15). The double guide wheel (51) is fixed to the lower part of the support rod (41) or the bottom of the seat frame (2) by a wheel frame (52). The rod body of the guide support rod (15) is embedded between the upper and lower rollers of the double guide wheel (51) to form a rolling friction fit.

7. A telescopic support frame structure for a sofa bed according to claim 6, characterized in that: The cross-section of the guide support rod (15) is circular or rectangular, and the roller groove of the double guide wheel (41) matches it.

8. A telescopic support frame structure for a sofa bed according to claim 5, characterized in that: The support pole (41) is L-shaped, with its vertical section (411) fixedly connected to the seat frame (2), and its horizontal section (412) extending towards the back of the sofa. The double guide wheel (45) is fixedly installed below the end of the horizontal section (412) of the support pole (42).

9. A telescopic support frame structure for a sofa bed according to claim 5, characterized in that: The backrest mounting support assembly includes a positioning mounting piece (61) for connecting the backrest frame and a locking pin (62). The locking pin (62) includes a male pin (621) and a female pin (622). The positioning mounting piece (61) and the male pin (621) are respectively provided with matching screw holes. The female pin (622) is fixed to the upper part of the rear section (422) of the first connecting rod (42) or the upper part of the second connecting rod (43) by a fixing seat (623).

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