A quick folding herringbone ladder based on a multi-link linkage mechanism

Abstract

The application discloses a kind of quick folding herringbone ladder based on multi-connecting rod linkage mechanism, including two ladder bodies, the middle part of two ladder bodies is fixed with several steps, the upper end of two ladder bodies is fixed with two connecting seats, and the middle part of four connecting seats is rotatably connected with main shaft rod;Each ladder body is fixed with support rod on both sides, each ladder body is provided with clamping groove at both ends, each adjacent two support rods are provided with connecting structure on outer surface, and two bases are arranged on connecting structure;Connecting structure can slide with two bases in the direction of ladder body height to adjust the height of herringbone ladder.The application realizes the effect of self-adaptive adjustment of multi-connecting rod linkage ladder body height, and synchronously completes height switching and posture limiting during the whole process of unfolding locking and folding resetting, without additional separate control, without step-by-step manual adjustment of height and positioning locking, simple and smooth operation process, effectively improves the use flexibility and operation convenience of herringbone ladder.

Description

Technical Field

[0001] This invention relates to the field of A-frame ladder technology, and more particularly to a fast-folding A-frame ladder based on a multi-link linkage mechanism. Background Technology

[0002] A-frame ladders, as portable climbing tools frequently used in daily work and industrial settings, feature a symmetrical A-frame structure design, possessing core characteristics of structural stability, even stress distribution, and strong self-support. They can be placed independently and stably without relying on external support structures such as walls or columns, adapting to various complex environments. Their ease of operation and wide applicability have led to their widespread use in many fields, including home life, property maintenance, construction, and factory operation and maintenance.

[0003] While existing A-frame ladders can meet basic daily work needs, they still have significant limitations in practical use. Most A-frame ladders have a relatively fixed overall height in both unfolded and folded states, making it difficult to effectively reduce their overall size when folded for storage, thus occupying considerable storage space and causing inconvenience for daily storage and transportation. Furthermore, the working height of the ladder is difficult to flexibly adapt to actual scenarios. Ordinary models lack height adjustment capabilities, making it difficult to meet the needs of work at different heights. A-frame ladders equipped with height adjustment mechanisms require manual, step-by-step adjustments, which are cumbersome and time-consuming, significantly reducing the flexibility and ease of use of the A-frame ladder. Therefore, it is necessary to invent a quick-folding A-frame ladder based on a multi-link linkage mechanism to solve the above problems. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides the following technical solution: a quick-folding A-frame ladder based on a multi-link linkage mechanism, comprising two ladder bodies, each of which has several treads fixed in the middle, and each of which has two connecting seats fixed at the upper end, with a main shaft rotatably connected to the middle of the four connecting seats; Each of the ladder bodies has a support rod fixed on both sides, and each of the ladder bodies has a slot at both ends. A connecting structure is provided on the outer surface of each pair of adjacent support rods, and two bases are provided on the connecting structure. The connecting structure can slide along the height of the ladder body with the two bases to adjust the height of the A-frame ladder.

[0005] Preferably, the connecting structure includes two connecting frames, with a stabilizing rod rotatably connected to the other end of each connecting frame. A first limiting plate is fixed to one end of the stabilizing rod, and a second limiting plate is fixed to the other end of the stabilizing rod. A spring is fixed to one side of the second limiting plate, and a sliding frame is fixed to the other end of the spring. A handle is fixed to the middle of the sliding frame. Two connecting frames are rotatably connected to the outer surface of the stabilizing rod, with a fixing rod fixed to the other end of each connecting frame. A base is rotatably connected to the outer surface of each fixing rod. A sliding groove is formed in the middle of each base, and a through groove is formed on one side of each sliding groove.

[0006] Preferably, one end of each support rod is fixed to the middle of one side of each ladder body, the vertical cross-section of each support rod is T-shaped, the outer surface of each support rod is rotatably connected to the lower end of each connecting frame, the upper end of each connecting frame is rotatably connected to the outer surface of the stabilizer rod near the first limiting plate, and the middle of the two first limiting plates is fixed to the near ends of the two stabilizers.

[0007] Preferably, the two second limiting discs are fixed at the middle of the two stabilizing rods at opposite ends, the two second limiting discs are fixed at the adjacent ends of the two springs at opposite ends, the two springs are fixed at the adjacent ends of the two sliding frames at opposite ends, the inner walls of the two sliding frames are slidably connected to the outer surfaces of the two stabilizing rods at opposite ends, and the two handles are fixed at both ends in the middle of the two sliding frames, with each handle being U-shaped.

[0008] Preferably, the upper end of each connecting frame is rotatably connected to the outer surface of the stabilizing rod, the upper end of one connecting frame is in contact with the outer surface of one sliding frame, the lower end of each connecting frame is fixed to the middle of each fixed rod, the outer surface of each fixed rod is rotatably connected to the inner wall of each base, the outer surface of each fixed rod is in contact with the inner wall of one slot, each slot passes through one end of each ladder body, the outer surface of each ladder body is slidably connected to the inner walls of two slide grooves, each slide groove is opened in the middle of each base, and each through groove passes through one side of each base.

[0009] Preferably, each of the ladder bodies has a stabilizing groove at both ends, and two stabilizing blocks are slidably connected to the inner wall of each stabilizing groove. A scissor bracket is rotatably connected to the lower end of each pair of adjacent stabilizing blocks. Several rotating shafts are rotatably connected to the middle of each scissor bracket, and one of the foot rods is rotatably connected to the near ends of two of the rotating shafts. A slider is rotatably connected to the other two ends of each scissor bracket, and a limit groove is provided at the lower end of each sliding groove.

[0010] Preferably, the outer surfaces of two adjacent stabilizing blocks are slidably connected to the inner walls on both sides of each stabilizing groove, the lower ends of two adjacent stabilizing blocks are rotatably connected to the upper end of each scissor bracket, and the middle parts of several rotating shafts are rotatably connected to the middle of each scissor bracket, with the outer surfaces of two relatively close rotating shafts in contact with the inner walls at both ends of one of the foot rods.

[0011] Preferably, the upper ends of two adjacent sliders are rotatably connected to the lower end of the scissor bracket, and the outer surfaces of two adjacent sliders are slidably connected to the inner walls on both sides of one of the limiting grooves. Each limiting groove is opened on the lower side of each base, and the vertical cross-section of each slider is inverted T-shaped, and the vertical cross-section of each stabilizing block is T-shaped.

[0012] Preferably, each of the fixed rods has a chuck fixed at one end, a drive frame rotatably connected to the outer surface of each fixed rod, a connecting shaft rotatably connected to the other end of each drive frame, a support frame rotatably connected to the outer surface of each connecting shaft, and a support shaft rotatably connected to the other end of each support frame.

[0013] Preferably, the middle of each chuck is fixed to the end of each fixed rod away from the base, the upper end of each drive frame is rotatably connected to the outer surface of each fixed rod away from the base, the lower end of each drive frame is rotatably connected to one side of each connecting shaft, the lower end of each support frame is rotatably connected to the other side of each connecting shaft, the upper end of each support frame is rotatably connected to the outer surface of each support shaft, and one end of each support shaft is fixed to the middle of each connecting frame.

[0014] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention achieves the effect of adaptive adjustment of the height of the multi-link linkage ladder. The height switching and posture limit are completed simultaneously in the whole process of unfolding and locking and folding and resetting. No additional separate control is required, and no step-by-step manual adjustment of height and positioning locking is required. The operation process is simple and smooth, effectively improving the flexibility and convenience of use of the A-frame ladder. (2) The present invention realizes the adaptive adjustment effect of the treads as the ladder unfolds, which can ensure that the treads layout is always reasonable and regular, and can flexibly adapt to the usage requirements of different working heights. It effectively solves the problem of fixed tread spacing and poor adaptability of traditional A-frame ladders, and significantly improves the overall practicality of A-frame ladders. (3) The present invention realizes the multi-point support effect during the unfolding process of the ladder body, effectively increases the stress points of the A-frame ladder, optimizes the overall stress distribution, significantly enhances the support strength and balance performance of the ladder body, effectively avoids the deviation and swaying problems that occur during the use of the ladder body, and greatly improves the stability and safety performance of the A-frame ladder during use. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a fast folding A-frame ladder based on a multi-link linkage mechanism proposed in this invention. Figure 2 This is a schematic diagram of the unfolded state structure of a fast folding A-frame ladder based on a multi-link linkage mechanism proposed in this invention; Figure 3 This is a partial cross-sectional view of a rapid folding A-frame ladder based on a multi-link linkage mechanism proposed in this invention. Figure 4 This invention proposes a rapid folding A-frame ladder based on a multi-link linkage mechanism. Figure 3 Enlarged view of the structure of section A in the middle; Figure 5 This invention proposes a rapid folding A-frame ladder based on a multi-link linkage mechanism. Figure 3 Enlarged view of the structure of section B in the middle; Figure 6 This is a schematic diagram of a quick-folding A-frame ladder connecting frame structure based on a multi-link linkage mechanism proposed in this invention; Figure 7 This is a cross-sectional view of a quick-folding A-frame ladder base based on a multi-link linkage mechanism proposed in this invention; Figure 8 This is a partial structural diagram of a rapid folding A-frame ladder based on a multi-link linkage mechanism proposed in this invention.

[0016] In the diagram: 1. Ladder body; 2. Step; 3. Connecting seat; 4. Main shaft; 5. Support rod; 6. Connecting frame; 7. Stabilizing rod; 8. First limiting plate; 9. Second limiting plate; 10. Spring; 11. Sliding frame; 12. Handle; 13. Connecting frame; 14. Fixing rod; 15. Base; 16. Slide groove; 17. Through groove; 18. Slot; 19. Stabilizing groove; 20. Stabilizing block; 21. Scissor bracket; 22. Rotating shaft; 23. Step rod; 24. Slider; 25. Limiting groove; 26. Chuck; 27. Drive frame; 28. Connecting shaft; 29. ​​Support frame; 30. Support shaft. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0018] Please see Figure 1 - Figure 8As shown, the system includes two ladder bodies 1, each with several treads 2 fixed in the middle. Two connecting seats 3 are fixed to the upper ends of each ladder body 1, and a main shaft 4 is rotatably connected to the middle of each of the four connecting seats 3. Support rods 5 are fixed to both sides of each ladder body 1, and slots 18 are provided at both ends of each ladder body 1. A connecting structure is provided on the outer surface of every two adjacent support rods 5. The connecting structure includes two connecting frames 6, with a stabilizing rod 7 rotatably connected to the other end of each connecting frame 6. A first limiting plate 8 is fixed to one end of the stabilizing rod 7, and a second limiting plate 9 is fixed to the other end. A spring 10 is fixed to one side of the second limiting plate 9, and a sliding frame 11 is fixed to the other end of the spring 10. A handle 12 is fixed to the middle of the sliding frame 11. Two connecting frames 13 are rotatably connected to the outer surface of the stabilizing rod 7, with fixing rods 14 fixed to the other ends of each connecting frame 13. Bases 15 are rotatably connected to the outer surface of each fixing rod 14, and a sliding groove 16 is provided in the middle of each base 15. A through slot 17 is provided on one side. Under the continuous elastic action of the spring 10, the fixing rod 14 always maintains a tight contact with the inner wall of the base 15. Even if the spring 10 is compressed to its limit, the fixing rod 14 will not detach from the base 15, ensuring the continuity and stability of the transmission process. During the manual unfolding of the ladder body 1, as the height of the ladder body gradually increases, the fixing rod 14, under the elastic support of the spring 10, always moves synchronously against the inner wall of the base 15, cooperating with the unfolding action of the ladder body 1 to complete the height adaptive adjustment. When the ladder body 1 is folded up, as the height of the ladder body gradually decreases, the fixing rod 14 also moves in the opposite direction against the inner wall of the base 15 under the action of the spring 10, synchronously adapting to the retraction action of the ladder body 1. No additional manual intervention is required throughout the process, which not only ensures the smoothness of height adjustment, but also further enhances the support stability of the ladder body during the adjustment process, avoiding problems such as transmission jamming and ladder body shaking caused by the fixing rod 14 detaching from the base 15.

[0019] Please refer to it again. Figure 1 - Figure 8As shown, one end of each support rod 5 is fixed to the middle of one side of each ladder body 1. The vertical cross-section of each support rod 5 is T-shaped. The outer surface of each support rod 5 is rotatably connected to the lower end of each connecting frame 6. The upper end of each connecting frame 6 is rotatably connected to the outer surface of the stabilizer 7 near the first limiting plate 8. The middle of the two first limiting plates 8 is fixed to the near ends of the two stabilizer 7. The middle of the two second limiting plates 9 is fixed to the far ends of the two stabilizer 7. The near sides of the two second limiting plates 9 are fixed to the far ends of the two springs 10. The near ends of the two springs 10 are fixed to the far sides of the two sliding frames 11. The inner walls of the two sliding frames 11 are slidably connected to the outer surfaces of the far sides of the two stabilizer 7. The two handles 12 are fixed at both ends. In the middle of the two sliding frames 11, each handle 12 is U-shaped. The upper end of each connecting frame 13 is rotatably connected to the outer surface of the stabilizing rod 7. The upper end of one connecting frame 13 is in contact with the outer surface of one of the sliding frames 11. The lower end of each connecting frame 13 is fixed to the middle of each fixed rod 14. The outer surface of each fixed rod 14 is rotatably connected to the inner wall of each base 15. The outer surface of each fixed rod 14 is in contact with the inner wall of one of the slots 18. Each slot 18 passes through one end of each ladder body 1. The outer surface of each ladder body 1 is slidably connected to the inner wall of two slide grooves 16. Each slide groove 16 is opened in the middle of each base 15. Each through groove 17 passes through one side of each base 15.

[0020] Working principle: The two ladder bodies 1 of the A-frame ladder are unfolded by human force. Supported by the connecting seats 3 and main shaft 4 fixed at the upper end, the two ladder bodies 1 flip open, simultaneously causing the support rods 5 fixed on both sides of the ladder bodies 1 to move in linkage. The support rods 5, with adjacent vertical cross-sections forming a T-shape, drive the connecting frames 6 rotatably connected to their outer surfaces to move synchronously under the constraint of the T-shaped protrusions. The two moving connecting frames 6 drive the stabilizing rod 7 rotatably connected at the upper end to move downwards. During the downward movement of the stabilizing rod 7, the first limiting plate 8 fixed at one end forms a limiting constraint on the two connecting frames 6, while the second limiting plate 9 fixed at the other end of the stabilizing rod 7, in conjunction with the spring 10, continuously compresses the sliding frame 11. The sliding frame 11 synchronously drives the two connecting frames 13 rotatably connected to the stabilizing rod 7 to move. Under pressure, the two connecting frames 13 drive the fixed rod 14 fixed at the lower end to move against the inner wall of the base 15, and under the pressure of the ladder bodies 1, maintain the compressed and stored state of the spring 10. As the stabilizing rod 7 continues to move downwards, it synchronously drives the rotating connecting frame 13 to move downwards. The downward-moving connecting frame 13 causes the fixed rod 14 at the bottom to press against the base 15. The base 15 slides with the ladder body 1 through the sliding groove 16 in the middle and moves downwards synchronously under the limiting effect of the ladder body 1. Until the two connecting frames 6 flip from the tilted posture to the horizontal posture, the ladder body 1 is fully unfolded and reaches the optimal stable use state. At this time, the fixed rod 14 slides to the corresponding position of the preset slot 18 of the ladder body 1. The spring 10, which was continuously compressed in the early stage, releases its elasticity and presses against the sliding frame 11. Then, the sliding frame 11 pushes the connecting frame 13, so that the fixed rod 14 at the bottom of the connecting frame 13 is inserted into the slot 18, thereby locking the unfolding angle and support height of the ladder body and automatically completing the unfolding and raising operation of the A-frame ladder. When folding and storing, pull the handles 12 on both sides. The handles 12 drive the sliding bracket 11 to compress the spring 10, which in turn moves the connecting bracket 13 in the opposite direction, causing the fixing rod 14 to disengage from the slot 18 and unlock. This allows the ladder body 1 to be folded up, completing the folding and height reduction of the A-frame ladder. This structure can achieve multi-link linkage ladder body height adaptive adjustment during the unfolding and storage process of the A-frame ladder. The height switching and posture limit are completed simultaneously throughout the unfolding, locking, and folding reset processes. No additional separate control or step-by-step manual height adjustment and positioning locking is required. The operation process is simple and smooth, effectively improving the flexibility and ease of use of the A-frame ladder.

[0021] When the overall height of an A-frame ladder changes, the spacing and position of each step 2 will also shift. If the steps 2 cannot be adjusted synchronously, it will cause uneven stepping distance, awkward standing posture, and unstable force, affecting work safety and user experience. Therefore, while the ladder changes height, the automatic following and adaptive adjustment of the step 2 structure can ensure that the step 2 layout is always reasonable and neat, adapting to the needs of different working heights, and effectively improving the overall practicality of the A-frame ladder.

[0022] Please see Figure 1 - Figure 8As shown, each ladder body 1 has a stabilizing groove 19 at both ends. Two stabilizing blocks 20 are slidably connected to the inner wall of each stabilizing groove 19. A scissor-type bracket 21 is rotatably connected to the lower end of every two adjacent stabilizing blocks 20. Several rotating shafts 22 are rotatably connected to the middle of each scissor-type bracket 21. One of the steps 23 is rotatably connected to the near ends of two rotating shafts 22. Slider 24s are rotatably connected to both ends of each scissor-type bracket 21. A limit groove 25 is provided at the lower end of each slide groove 16. The outer surfaces of two adjacent stabilizing blocks 20 are slidably connected to the inner walls on both sides of each stabilizing groove 19. The lower ends of two adjacent stabilizing blocks 20 are rotatably connected to the upper end of each scissor-type bracket 21. Several rotating shafts 22 are rotatably connected to the middle of each scissor-type bracket 21. The outer surfaces of two adjacent rotating shafts 22 are in contact with the inner walls at both ends of one of the steps 23. The upper ends of two adjacent sliders 24 are rotatably connected to the scissor-type bracket 21. At the lower end of the scissor bracket 21, the outer surfaces of two adjacent sliders 24 are slidably connected to the inner walls on both sides of one of the limiting grooves 25. Each limiting groove 25 is opened on the lower side of each base 15. The vertical cross-section of each slider 24 is set in an inverted T shape, and the vertical cross-section of each stabilizing block 20 is set in a T shape. The scissor bracket 21 will expand or retract synchronously with the movement of the ladder body 1, and drive the step rods 23 to move synchronously. When the ladder body 1 is expanded, the scissor bracket 21 gradually unfolds under the traction of the stabilizing block 20 and the slider 24. Several pivot rods 22 connected in the middle are displaced accordingly, thereby driving the step rods 23 connected in the outer surface to unfold synchronously, gradually adjusting to a uniform spacing suitable for human stepping, ensuring the comfort and stability of the user when stepping. When the ladder body 1 is folded for storage, the scissor bracket 21 retracts synchronously, and the pivot rods 22 drive the step rods 23 to move closer synchronously, effectively reducing the overall volume of the ladder body after folding, making it easy to store and transport.

[0023] Working principle: The two ladder bodies 1 of the A-frame ladder are unfolded to both sides by human force. The ladder bodies 1 simultaneously drive the support rods 5 fixed to them to move. The support rods 5 pull the stabilizing rods 7 to move synchronously through the rotating connecting frame 6. The moving stabilizing rods 7 further drive the fixed rods 14 fixed at the lower end of the connecting frame 13 to move through the rotating connecting frame 13. This drives the base 15 to move accordingly, so that the distance between the bottom of the base 15 and the bottom of the ladder body 1 gradually increases. During this process, two stabilizing blocks 20 slidably connected within the stabilizing grooves 19 at each end of the ladder body 1, in conjunction with two sliding blocks 24 sliding on the inner wall of the limiting groove 25 at the bottom of the sliding groove 16 in the middle of the base 15, exert a traction effect on the scissor-type bracket 21, which is rotatably connected to the lower end of the stabilizing blocks 20 and rotatably connected to the upper end of the sliding blocks 24, causing the scissor-type bracket 21 to slowly unfold. When the scissor-type bracket 21 unfolds, it drives several rotating shafts 22 rotatably connected in its middle to move synchronously. The moving rotating shafts 22 then pull the treads 23 rotatably connected to their outer surfaces to unfold synchronously until the treads 23 are adjusted to a uniform interval suitable for human stepping, facilitating stable stepping for the user. This structure achieves an adaptive adjustment effect of the treads 23 as the ladder body unfolds, ensuring that the layout of the treads 23 is always reasonable and regular, and can flexibly adapt to the usage needs of different working heights. It effectively solves the problems of fixed spacing and poor adaptability of the treads 23 in traditional A-frame ladders, significantly improving the overall practicality of the A-frame ladder.

[0024] A-frame ladders rely solely on the two side supports during operation, resulting in a single, concentrated stress point, limited support range, and a relatively constrained structural design. Factors such as uneven ground and foot traffic can easily cause the ladder to shift or sway, leading to poor overall stability and potential safety hazards. Therefore, adding auxiliary support structures to increase the number of stress points and optimize the overall stress distribution can effectively enhance the support strength and balance of the A-frame ladder, significantly improving its stability and safety during use.

[0025] Please see Figure 1 - Figure 8 As shown, each fixed rod 14 has a chuck 26 fixed to one end, a drive frame 27 rotatably connected to the outer surface of each fixed rod 14, a connecting shaft 28 rotatably connected to the other end of each drive frame 27, a support frame 29 rotatably connected to the outer surface of each connecting shaft 28, and a support shaft 30 rotatably connected to the other end of each support frame 29. The middle of each chuck 26 is fixed to the end of each fixed rod 14 away from the base 15. The upper end of each drive frame 27 is rotatably connected to the outer surface of each fixed rod 14 away from the base 15, and the lower end of each drive frame 27 is rotatably connected to one side of each connecting shaft 28. Each support... The lower end of the frame 29 is rotatably connected to the other side of each connecting shaft 28, and the upper end of each support frame 29 is rotatably connected to the outer surface of each support shaft 30. One end of each support shaft 30 is fixed in the middle of each connecting frame 13. The support frame 29 and the drive frame 27 are stably supported on the ground under the precise cooperation of the connecting shaft 28. The lower ends of the two are closely attached to the ground, forming a symmetrical and stable auxiliary support structure. Together with the bottom of the ladder body 1, they form a multi-point support system, which effectively expands the support contact area of ​​the ladder body, disperses the concentrated force on the ladder body 1, and avoids safety hazards such as tilting and shaking of the ladder body due to excessive force on a single support point.

[0026] Working principle: The two ladder bodies 1 of the A-frame ladder are unfolded to both sides by human force. The support rod 5, which is fixedly connected to the ladder body 1, moves synchronously with the ladder body 1. The support rod 5 pulls the stabilizing rod 7 to move synchronously through the rotating connecting frame 6. The moving stabilizing rod 7 further drives the rotating connecting frame 13 to move, which not only drives the fixed rod 14 fixed at the lower end of the connecting frame 13 to move synchronously, but also causes the tilt angle of the connecting frame 13 to change adaptively, thereby driving the support shaft 30 fixed in the middle of the connecting frame 13 to move synchronously. The moving support shaft 30 pulls the support frame 29, which is rotatably connected to its outer surface, to move synchronously. The other end of the support frame 29, via a rotatably connected connecting shaft 28, drives the drive frame 27, which is rotatably connected to the other side of the connecting shaft 28, to move. Because the drive frame 27 is rotatably connected to the outer surface of the fixed rod 14 and is subject to dual constraints from the connecting frame 13 and the chuck 26, it flips under the traction of the support frame 29. As the ladder body 1 gradually unfolds into place, the lower ends of the support frame 29 and the drive frame 27 land synchronously under the connection of the connecting shaft 28, forming a stable auxiliary support. This structure achieves multi-point support during the unfolding process of the ladder body 1, effectively increasing the stress points of the A-frame ladder, optimizing the overall stress distribution, significantly enhancing the support strength and balance performance of the ladder, effectively avoiding deviation and swaying problems during ladder use, and greatly improving the stability and safety performance of the A-frame ladder during use.

[0027] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A rapid folding A-frame ladder based on a multi-link linkage mechanism, comprising two ladder bodies (1), characterized in that, Several treads (2) are fixed in the middle of both ladder bodies (1), and two connecting seats (3) are fixed at the upper end of both ladder bodies (1). A main shaft (4) is rotatably connected in the middle of the four connecting seats (3). Each of the ladder bodies (1) is fixed with a support rod (5) on both sides, and each of the ladder bodies (1) is provided with a slot (18) at both ends. A connecting structure is provided on the outer surface of each pair of adjacent support rods (5), and two bases (15) are provided on the connecting structure. The connecting structure can slide with the two bases (15) in the height direction of the ladder body (1) to adjust the height of the A-frame ladder.

2. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 1, characterized in that, The connecting structure includes two connecting frames (6), and a stabilizing rod (7) is rotatably connected to the other end of the two connecting frames (6). A first limiting plate (8) is fixed to one end of the stabilizing rod (7), and a second limiting plate (9) is fixed to the other end of the stabilizing rod (7). A spring (10) is fixed to one side of the second limiting plate (9), and a sliding frame (11) is fixed to the other end of the spring (10). A handle (12) is fixed to the middle of the sliding frame (11). Two connecting frames (13) are rotatably connected to the outer surface of the stabilizing rod (7). A fixing rod (14) is fixed to the other end of each of the two connecting frames (13). A base (15) is rotatably connected to the outer surface of each of the two fixing rods (14). A sliding groove (16) is opened in the middle of each base (15), and a through groove (17) is opened on one side of each sliding groove (16).

3. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 2, characterized in that, One end of each support rod (5) is fixed to the middle of one side of each ladder body (1). The vertical cross-section of each support rod (5) is T-shaped. The outer surface of each support rod (5) is rotatably connected to the lower end of each connecting frame (6). The upper end of each connecting frame (6) is rotatably connected to the outer surface of the stabilizer (7) near the first limiting plate (8). The middle of the two first limiting plates (8) is fixed to the near ends of the two stabilizers (7).

4. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 2, characterized in that, The two second limiting discs (9) are fixed in the middle to the two stabilizing rods (7) at opposite ends. The two second limiting discs (9) are fixed on the near side to the two springs (10) at opposite ends. The two springs (10) are fixed on the near side to the two sliding frames (11) at opposite ends. The inner walls of the two sliding frames (11) are slidably connected to the outer surface of the two stabilizing rods (7) at opposite ends. The two handles (12) are fixed at both ends to the middle of the two sliding frames (11). Each handle (12) is U-shaped.

5. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 2, characterized in that, The upper end of each connecting frame (13) is rotatably connected to the outer surface of the stabilizing rod (7). The upper end of one of the connecting frames (13) is in contact with the outer surface of one of the sliding frames (11). The lower end of each connecting frame (13) is fixed to the middle of each fixed rod (14). The outer surface of each fixed rod (14) is rotatably connected to the inner wall of each base (15). The outer surface of each fixed rod (14) is in contact with the inner wall of one of the slots (18). Each slot (18) passes through one end of each ladder body (1). The outer surface of each ladder body (1) is slidably connected to the inner wall of two of the sliding grooves (16). Each sliding groove (16) is opened in the middle of each base (15). Each through groove (17) passes through one side of each base (15).

6. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 2, characterized in that, Each of the ladder bodies (1) has a stabilizing groove (19) at both ends. Each of the stabilizing grooves (19) has two slidably connected to the inner wall of two stabilizing blocks (20). Each pair of adjacent stabilizing blocks (20) has a scissor bracket (21) rotatably connected to the lower end. Each of the scissor brackets (21) has several rotating shafts (22) rotatably connected to the middle part. One of the two rotating shafts (22) is rotatably connected to a step (23) at the near end. Each of the other two ends of each scissor bracket (21) has a slider (24) rotatably connected to the other end. Each of the sliding grooves (16) has a limit groove (25) at the lower end.

7. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 6, characterized in that, The outer surfaces of two adjacent stabilizing blocks (20) are slidably connected to the inner walls on both sides of each stabilizing groove (19). The lower ends of two adjacent stabilizing blocks (20) are rotatably connected to the upper end of each scissor bracket (21). The middle parts of several rotating shafts (22) are rotatably connected to the middle part of each scissor bracket (21). The outer surfaces of two relatively close rotating shafts (22) are in contact with the inner walls at both ends of one of the foot rods (23).

8. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 6, characterized in that, The upper ends of two adjacent sliders (24) are rotatably connected to the lower end of the scissor bracket (21). The outer surfaces of two adjacent sliders (24) are slidably connected to the inner walls on both sides of one of the limiting grooves (25). Each limiting groove (25) is opened on the lower side of each base (15). The vertical cross-section of each slider (24) is set in an inverted T shape. The vertical cross-section of each stabilizing block (20) is set in a T shape.

9. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 2, characterized in that, Each of the fixed rods (14) has a chuck (26) fixed at one end, a drive frame (27) rotatably connected to the outer surface of each fixed rod (14), a connecting shaft (28) rotatably connected to the other end of each drive frame (27), a support frame (29) rotatably connected to the outer surface of each connecting shaft (28), and a support shaft (30) rotatably connected to the other end of each support frame (29).

10. A quick-folding A-frame ladder based on a multi-link linkage mechanism according to claim 9, characterized in that, The middle of each chuck (26) is fixed to the end of each fixed rod (14) away from the base (15). The upper end of each drive frame (27) is rotatably connected to the outer surface of the side of each fixed rod (14) away from the base (15). The lower end of each drive frame (27) is rotatably connected to one side of each connecting shaft (28). The lower end of each support frame (29) is rotatably connected to the other side of each connecting shaft (28). The upper end of each support frame (29) is rotatably connected to the outer surface of each support shaft (30). One end of each support shaft (30) is fixed to the middle of each connecting frame (13).

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