Dual-purpose ladder

Abstract

This utility model discloses a dual-purpose A-frame ladder, including a front ladder and a rear ladder that are rotatably fitted at their upper ends, and an adjustment mechanism for adjusting the opening and closing angle of the two ladders. The adjustment mechanism includes two connecting rods and a limiting component. The two connecting rods are located on the left and right sides respectively, with one end rotatably connected to the front ladder and the other end having several positioning holes evenly distributed along its length. The rear ladder includes two rear uprights and several rear cross steps located between the two rear uprights. One of the rear cross steps has an installation channel along its length. The limiting component is slidably disposed in the installation channel, and its two ends slide through the corresponding rear uprights. The limiting component has an operating part extending out of the rear cross step, which is used to control the simultaneous extension and retraction of the end of the limiting component. The connecting rod has several positioning holes for the end of the limiting component to be inserted. The other end of the connecting rod is inserted into the two ends of the limiting component through the limiting holes at the same position, so as to achieve locking of the front ladder and the rear ladder at any opening and closing angle. Compared with the existing technology, the advantage of this utility model is that it realizes "fine adjustment of the height of the A-frame ladder", filling the gap of traditional dual-purpose ladders in the "slight height difference" scenario.

Description

Technical Field

[0001] This utility model relates to the field of folding ladder technology, and in particular to a dual-purpose A-frame ladder. Background Technology

[0002] A-frame ladders are self-supporting, double-sided climbing tools. They consist of two ladders hinged at their top ends to form an "A" shape, allowing for use without relying on a wall. They are widely used in medium-height work scenarios such as interior decoration and loading / unloading goods. Their advantages include rapid deployment, small footprint, and easy mobility. However, due to the fixed hinge angle, the maximum standing height of an A-frame ladder is constant, which is insufficient for some higher work scenarios. Therefore, some A-frame ladders on the market have been developed where the rear ladder, when folded, can be flipped 180 degrees to form a straight ladder, thus meeting the needs of more work situations.

[0003] For example, the Chinese utility model patent CN207260950U, entitled "A Dual-Purpose Double-Sided Climbing Ladder," includes a front ladder and a rear ladder. The upper ends of the two ladders are rotatably connected. The rear end of the top step of the front ladder extends backward to form a platform. The left and right ends of the platform are provided with clearance openings corresponding to the left and right second columns of the rear ladder. A rigid connecting rod is provided between the two ladders. One end of the rigid connecting rod is movably connected to the front ladder, and the other end is quickly connected to the rear ladder. A pull rod is provided between the two ladders. One end of the pull rod is movably connected to the rear ladder, and the other end of the pull rod is provided with a hook. The top step of the front ladder is provided with a latch hole. When the rear ladder is rotated to a 180-degree angle with the front ladder, the hook hooks onto the latch hole to limit the rear ladder, forming a straight ladder. At the same time, the clearance opening cooperates with the pull rod to limit the rear ladder and prevent it from rotating.

[0004] The above solution can meet more work scenarios by converting between A-frame and straight ladders. However, in special scenarios where the A-frame ladder is slightly too short and the straight ladder cannot be deployed due to space limitations, users cannot work at that intermediate height. Even if there is enough space to switch the A-frame ladder to a straight ladder, when faced with a height difference of only ten centimeters, users can only repeatedly disassemble and switch between the two modes, which is cumbersome, inefficient, and prone to wear and tear on rigid connecting rods and tie rods, posing a safety hazard. Utility Model Content

[0005] This utility model addresses the problem that existing dual-purpose ladders cannot be used in special scenarios where "the height of the A-frame ladder is slightly lower and the straight ladder cannot be unfolded due to space height limitations," or require repeated disassembly and reassembly to switch modes when facing a special height difference of "only ten centimeters." The technical problem to be solved by this utility model is to provide a dual-purpose A-frame ladder whose height can be finely adjusted when in A-frame form.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a dual-purpose A-frame ladder, including a front ladder and a rear ladder that are rotatably fitted at their upper ends, and an adjustment mechanism for adjusting the opening and closing angles of the front and rear ladders. The adjustment mechanism includes two connecting rods and a limiting component. The two connecting rods are located on the left and right sides respectively, with one end rotatably connected to the front ladder and the other end having a plurality of positioning holes evenly distributed along its length. The rear ladder includes two rear uprights and a plurality of rear cross steps disposed between the two rear uprights. One of the rear cross steps has an installation channel along its length. The limiting component is slidably disposed in the installation channel, and its two ends slide through the corresponding rear uprights. The limiting component has an operating part extending out of the rear cross step. The operating part is used to control the simultaneous extension and retraction of the end of the limiting component. The connecting rod has a plurality of positioning holes into which the end of the limiting component can be inserted. The other end of the connecting rod is inserted into the two ends of the limiting component through the limiting holes at the same position, so as to achieve locking of the front and rear ladders at any opening and closing angle.

[0007] A further preferred embodiment of this utility model is as follows: the limiting assembly includes a limiting rod one, a limiting rod two, and an elastic element disposed between the limiting rod one and the limiting rod two. The two rear columns are provided with connecting holes corresponding to the installation channel. The ends of the limiting rod one and the limiting rod two pass through the connecting holes on the corresponding sides and are selectively inserted into the positioning holes. The elastic element is used to apply outward tension to the limiting rod one and the limiting rod two. The rear cross step is provided with a strip-shaped mounting hole. Each adjacent end of the limiting rod one and the limiting rod two is provided with an operating rod that passes through the strip-shaped mounting hole. The two operating rods form the operating part.

[0008] A further preferred embodiment of this utility model is that the strip-shaped mounting hole is located at the bottom of the rear cross pedal, and the operating lever hangs down naturally and is hidden below the tread surface of the rear cross pedal.

[0009] A further preferred embodiment of this utility model is: a support platform with a flange is fixed on the outer side wall of the two rear columns; the side of the connecting rod away from the front ladder leans diagonally downward against the top surface of the support platform, and the flange forms a lateral limit on the side wall of the connecting rod.

[0010] A further preferred embodiment of this utility model is that the elastic element is a cylindrical spring or a bent spring sheet.

[0011] A further preferred embodiment of this utility model is as follows: the rear cross step with an internal installation channel includes a pedal roller and connecting rollers located on both sides of the pedal roller. The pedal roller has an installation cavity communicating with the installation channel on both sides. The diameter of the installation cavity is larger than that of the installation channel, so that a step is formed at the inner end of the installation cavity. The two connecting rollers are slidably disposed in the installation cavity, and each of the two installation cavities is provided with a compression spring. One end of the compression spring abuts against the inner end of the connecting roller, and the other end abuts against the step. The connecting roller has a through hole for limiting rod one or limiting rod two to pass through. The through hole and the installation cavity are part of the installation channel. The inner sides of the two rear columns are provided with insertion positions for the connecting rollers to be inserted.

[0012] A further preferred embodiment of this utility model is: the front ladder includes two front uprights and a front cross step fixed between the two front uprights, and one end of the connecting rod is hinged to the outer wall of the corresponding front upright.

[0013] A further preferred embodiment of this utility model is as follows: the upper outer walls of the two front columns are each fixed with a connecting plate extending towards the rear ladder, the two connecting plates protrude outward to form a U-shaped connecting end, and the upper end of the rear ladder is inserted into the U-shaped connecting end and rotatedly connected with the U-shaped connecting end.

[0014] A further preferred embodiment of this utility model is as follows: a limiting hook is provided on the outer side wall of the upper end of the two back columns that are close to each other, and a limiting pin is fixed on the outer side wall of the two front columns. When the rear ladder is rotated to a 180-degree angle with the front ladder, the limiting hook is hooked on the limiting pin, and at the same time, the back of the front column is close to the rear column.

[0015] Compared with the prior art, the present invention has the following advantages: By incorporating connecting rods with positioning holes and sliding, telescopic limiting components, users can quickly and continuously adjust the opening angles of the front and rear ladders with one hand while maintaining the stability of the A-frame ladder structure. This results in an increase in standing height of several centimeters to over ten centimeters. The entire process does not require disassembling any parts, avoiding wear and tear on the connecting rods caused by frequent changes in form. It also eliminates safety hazards caused by rigid connection failures, achieving "fine-tuning of A-frame ladder height." This fills the gap in traditional dual-purpose ladders for scenarios where the height is just a little short, and also avoids the awkward situation where "the A-frame ladder is slightly too low, and the straight ladder cannot be unfolded due to space limitations."

[0016] This invention cleverly fills the functional gap between the two extreme forms of traditional dual-purpose ladders, namely "A-frame ladder" and "straight ladder," and provides a flexible and adjustable intermediate solution, enabling the ladder to better adapt to complex and ever-changing working environments and height requirements, and thus expanding its application scenarios. Attached Figure Description

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be regarded as a limitation on the scope of the present invention. In addition, unless otherwise specified, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

[0018] Figure 1 This is a three-dimensional structural diagram of a preferred embodiment of the present invention; Figure 2 This is a preferred embodiment of the present utility model. Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a front view of a preferred embodiment of the present invention; Figure 4 This is a preferred embodiment of the present utility model. Figure 3 Sectional view at point BB; Figure 5 This is a three-dimensional structural diagram of the preferred embodiment of the present invention after disassembling one side of the connecting rod; Figure 6 This is an exploded view of a preferred embodiment of the present invention.

[0019] In the diagram: 1. Front ladder; 11. Front upright; 12. Front cross step; 2. Rear ladder; 21. Rear upright; 211. Insertion position; 22. Rear cross step; 23. Step roller; 24. Connecting roller; 241. Through hole; 25. Mounting cavity; 26. Step; 27. Strip mounting hole; 3. Adjustment mechanism; 31. Connecting rod; 311. Positioning hole; 32. Limiting component; 321. Limiting rod one; 322. Limiting rod two; 323. Elastic element; 324. Operating rod; 235. Sleeve; 2351. Positioning sleeve; 4. Mounting channel; 5. Connecting hole; 6. Support platform; 7. Compression spring; 8. Connecting plate; 9. Limiting hook rod; 10. Limiting pin. Detailed Implementation

[0020] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Those skilled in the art will appreciate that these descriptions are merely descriptive and exemplary and should not be construed as limiting the scope of protection of the present invention.

[0021] It should be noted that similar labels in the following figures indicate similar items; therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

[0022] This embodiment mainly describes a double-purpose A-frame ladder, as detailed below: like Figures 1 to 6As shown, a dual-purpose A-frame ladder includes a front ladder 1 and a rear ladder 2. The upper ends of the front ladder 1 and the rear ladder 2 are rotatably connected, and an adjustment mechanism 3 is added between them. The adjustment mechanism 3 is used to adjust the opening angle between the two ladders, thereby realizing the fine adjustment of the height of the A-frame ladder. The adjustment mechanism 3 consists of two connecting rods 31 and a limiting component 32. The two connecting rods 31 are located on the left and right sides, one end of which is rotatably connected to the front ladder 1, and the other end is evenly distributed with a number of positioning holes 311 along the length direction. The rear ladder 2 includes two rear uprights 21 and several rear cross steps 22 disposed between the two rear uprights 21. One of the rear cross steps 22 has an installation channel 4 along its length. The limiting component 32 is slidably disposed in the installation channel 4, and its two ends slide through the corresponding rear uprights 21. The limiting component 32 has an operating part extending out of the rear cross step 22. The operating part is used to control the simultaneous extension and retraction of the end of the limiting component 32. The other end of the connecting rod 31 is inserted into the two ends of the limiting component 32 through the limiting hole 311 at the same position, so as to realize the locking of the front ladder 1 and the rear ladder 2 at any opening and closing angle. When the working height is between the "A-frame ladder is not enough, and the straight ladder is too high" value, the user does not need to flip it into a straight ladder. He only needs to squeeze the operating part with one hand to make the two ends of the limiting component 32 disengage from the current positioning hole 311. The front and rear ladders can continue to open and close while maintaining the A-frame shape. After releasing the hand, the elastic element 323 automatically pushes the two ends into the new positioning hole 311, instantly completing the slight angle adjustment of the front ladder 1 and the rear ladder 2, bringing an increase in standing height of a few centimeters to more than ten centimeters. The whole process does not disassemble any parts, avoiding the wear of the connecting rod caused by frequent switching of the form, and also eliminating the safety hazards caused by the failure of rigid connection. It realizes "fine adjustment of A-frame ladder height" and fills the gap of traditional dual-purpose ladders in the "slightly short of height" scenario.

[0023] like Figure 4 As shown, the limiting assembly 32 includes a first limiting rod 321, a second limiting rod 322, and an elastic element 323 disposed between the first limiting rod 321 and the second limiting rod 322. Both rear columns 21 are provided with connecting holes 5 corresponding to the mounting channel 4. The first limiting rod 321 and the second limiting rod 322 pass through the connecting holes 5 on the corresponding sides and are selectively inserted into the positioning holes 311. The elastic element 323 always applies outward tension to the first limiting rod 321 and the second limiting rod 322 to ensure self-locking during insertion. A strip-shaped mounting hole 27 is opened on the bottom surface of the rear cross step 22 along the length direction. Each of the adjacent ends of the first limiting rod 321 and the second limiting rod 322 is provided with an operating rod 324 extending from the strip-shaped mounting hole 27. The two operating rods 324 form an easily accessible operating part. The user pinches the operating lever 324 inward with their fingers, compressing the elastic element 323. The two limiting rods 321 and 322 retract inward simultaneously and disengage from the positioning hole 311, allowing the ladder angle to be freely adjusted. After releasing, the elastic element 323 resets, and the first limiting rod 321 and the second limiting rod 322 align and insert into the corresponding side connection hole, instantly locking with one hand.

[0024] Specifically, the strip-shaped mounting hole 27 is opened at the bottom of the rear footrest 22, and the operating lever 324 hangs down naturally and is hidden under the footrest. This design avoids the operating part from touching the bottom of the foot, and the operating lever 324 will not be hooked by foreign objects when folded and transported. The appearance is simple, and the bottom opening can prevent rainwater and dust from accumulating, extend the life of the internal elastic element 323, and ensure that the adjustment mechanism 3 remains flexible and smooth after multiple micro-adjustments.

[0025] like Figure 2 and Figure 5 As shown, the outer walls of the two rear columns 21 are fixed with support platforms 6 with flanges. The side of the connecting rod 31 away from the front ladder 1 leans diagonally downward against the top surface of the support platform 6. The flanges form a lateral limit on the side wall of the connecting rod 31. The support platform 6 supports the connecting rod 31 to prevent the connecting rod 31 from automatically drooping when the first limit rod 321 or the second limit rod 322 is disengaged from the positioning hole 311. It also avoids the situation where the user needs to hold the first limit rod 321 or the second limit rod 322 when they are inserted into the positioning hole 311.

[0026] Specifically, the elastic element 323 can be selected from either a cylindrical spring or a bent sheet depending on cost and life requirements. The cylindrical spring provides a linear large stroke, which is suitable for commercial scenarios that require frequent fine adjustments, while the sheet occupies less radial space and can meet the requirements of lightweight home-use designs. Both can maintain stable elasticity in environments ranging from -30 ℃ to 80 ℃, ensuring that the limit rods 321 and 322 are always subjected to sufficient external thrust, preventing accidental dislodgement due to elastic decay, and ensuring long-term reliability of the fine adjustment function.

[0027] like Figure 6As shown, the rear cross step 22 with the internal installation channel 4 is composed of three sections: a step roller 23 and connecting rollers 24 located on both sides of the step roller 23. The interior of both sides of the step roller 23 is provided with an installation cavity 25 that communicates with the installation channel 4. The diameter of the installation cavity 25 is larger than that of the installation channel 4, so that a step 26 is formed at the inner end of the installation cavity 25. The two connecting rollers 24 are slidably disposed in the installation cavity 25, and each of the two installation cavities 25 is provided with a compression spring 7. One end of the compression spring 7 abuts against the inner end of the connecting roller 24, and the other end abuts against the step 26. The interior of the connecting roller 24 has a through hole 241 for the limit rod 1 321 or the limit rod 2 322 to pass through. The through hole 241 and the installation cavity 25 are part of the installation channel 4. The inner sides of the two rear columns 21 are provided with an insertion position 211 for the outer end of the connecting roller 24 to be inserted. To facilitate the installation of the limiting assembly 32, the operating rod 324 is detachably connected to the limiting rod 321 or the limiting rod 322. For example, the limiting rod 321 or the limiting rod 322 is provided with a threaded hole, and one end of the operating rod 324 is a threaded post connected to the threaded hole. Alternatively, the connecting end of the operating rod 324 is provided with a sleeve 235 that fits inside the limiting rod 321 or the limiting rod 322. The two sleeves 235 are respectively interference-fitted with the limiting rod 321 and the limiting rod 322, and the sleeves 235 can extend into the installation channel 4 from the strip mounting hole 27. The opposite sides of the two sleeves 235 are provided with positioning sleeves 2351, and the two ends of the cylindrical spring 323 can be kept inside the positioning sleeves 2351. This design incorporates a retractable structure at both ends of the rear cross step 22, which features an installation channel 4. This allows for the detachable function of the rear cross step 22, facilitating the installation and maintenance of the limiting component 32. When the rear cross step 22 needs to be disassembled, the connecting rollers 24 on both sides are pressed inward to disengage it from the installation position 211. When installation is required, the first limiting rod 321 or the second limiting rod 322 is inserted into the channel 4, and the operating rod 324 and the cylindrical spring 323 are inserted through the strip mounting hole 27 to connect with the first limiting rod 321 and the second limiting rod 322.

[0028] Specifically, the front ladder 1 consists of two front uprights 11 and several front cross steps 12 fixed between the two front uprights 11. One end of the connecting rod 31 is rotatably connected to the outer wall of the front uprights 11. When the limiting rods 321 and 322 lock the connecting rod 31, the front uprights 11, the connecting rod 31, and the rear uprights 21 form a stable triangle.

[0029] Specifically, each of the two front uprights 11 has a connecting plate 8 fixed to its outer side wall at the upper end, extending towards the rear ladder 2. The two connecting plates 8 protrude outward to form a U-shaped connecting end. The upper end of the rear ladder 2 is inserted into the U-shaped connecting end and rotatably connected to the U-shaped connecting end through a pivot. This connection method allows the rear ladder 2 and the front ladder 1 to open and close. To avoid interference between the rear ladder 2 and the front ladder 1 when the rear ladder 2 flips over, a gap is left between the upper end of the rear upright 21 and the front upright 11.

[0030] Specifically, the outer side walls of the upper ends of the two rear columns 21 are equipped with limiting hooks 9, and the outer side walls of the two front columns 11 are equipped with corresponding limiting pins 10. When the user controls the operating rod 324 to disengage the limiting rod 1 321 and the limiting rod 2 322 from the positioning holes on both sides, the connecting rod 31 is allowed to hang down naturally. The rear ladder 2 can be flipped to form a straight ladder when it is 180° with the front ladder 1. The limiting hooks 9 are hooked onto the limiting pins 10. At the same time, the back of the front column 11 and the back of the rear column 21 are in contact with each other. The three rigid contacts together form a composite limit, preventing the rear ladder 2 from continuing to rotate relative to the front ladder 1.

[0031] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] The above provides a detailed description of a dual-purpose A-frame ladder provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand this utility model and its core ideas. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A double-purpose A-frame ladder, comprising a front ladder and a rear ladder with rotatable upper ends, characterized in that: It also includes an adjustment mechanism for adjusting the opening angle of the front and rear ladders. The adjustment mechanism includes two connecting rods and a limiting component. The two connecting rods are located on the left and right sides, with one end rotatably connected to the front ladder and the other end having several positioning holes evenly distributed along its length. The rear ladder includes two rear uprights and several rear cross steps located between the two rear uprights. One of the rear cross steps has an installation channel along its length. The limiting component is slidably disposed in the installation channel, and its two ends slide through the corresponding rear uprights. The limiting component has an operating part extending out of the rear cross step. The operating part is used to control the simultaneous extension and retraction of the end of the limiting component. The connecting rod has several positioning holes for the end of the limiting component to be inserted. The other end of the connecting rod is inserted into the two ends of the limiting component through the limiting holes at the same position to achieve locking of the front and rear ladders at any opening angle.

2. The double-purpose A-frame ladder according to claim 1, characterized in that: The limiting assembly includes a limiting rod one, a limiting rod two, and an elastic element disposed between the limiting rod one and the limiting rod two. The two rear columns are provided with connecting holes corresponding to the installation channel. The ends of the limiting rod one and the limiting rod two pass through the connecting holes on the corresponding sides and are selectively inserted into the positioning holes. The elastic element is used to apply outward tension to the limiting rod one and the limiting rod two. The rear cross step is provided with a strip-shaped mounting hole. Each adjacent end of the limiting rod one and the limiting rod two is provided with an operating rod that passes through the strip-shaped mounting hole. The two operating rods form the operating part.

3. A double-purpose A-frame ladder according to claim 2, characterized in that: The strip-shaped mounting hole is located at the bottom of the rear cross pedal, and the operating lever hangs down naturally and is hidden under the tread surface of the rear cross pedal.

4. A double-purpose A-frame ladder according to claim 2, characterized in that: A support platform with a flange is fixed on the outer side wall of the two rear columns; the side of the connecting rod away from the front ladder leans diagonally downward against the top surface of the support platform, and the flange forms a lateral limit on the side wall of the connecting rod.

5. A double-purpose A-frame ladder according to claim 2, characterized in that: The elastic element is a cylindrical spring or a bent sheet.

6. A double-purpose A-frame ladder according to claim 2, characterized in that: The rear cross step with an internal installation channel includes a pedal roller and connecting rollers located on both sides of the pedal roller. The pedal roller has an installation cavity on both sides that communicates with the installation channel. The diameter of the installation cavity is larger than that of the installation channel, so that a step is formed at the inner end of the installation cavity. The two connecting rollers are slidably disposed in the installation cavities, and each of the two installation cavities is provided with a compression spring. One end of the compression spring abuts against the inner end of the connecting roller, and the other end abuts against the step. The connecting roller has a through hole for limiting rod one or limiting rod two to pass through. The through hole and the installation cavity are part of the installation channel. The inner sides of the two rear columns are provided with insertion positions for the connecting rollers to be inserted.

7. A double-purpose A-frame ladder according to claim 2, characterized in that: The front ladder includes two front uprights and a front cross step fixed between the two front uprights. One end of the connecting rod is hinged to the outer wall of the corresponding front upright.

8. A double-purpose A-frame ladder according to claim 7, characterized in that: Both front columns have connecting plates fixed on their upper outer walls that extend toward the rear ladder. The two connecting plates protrude outward to form U-shaped connecting ends. The upper end of the rear ladder is inserted into the U-shaped connecting ends and rotates to connect with them.

9. A double-purpose A-frame ladder according to claim 8, characterized in that: The two back sides are rotatably mounted on the outer side of the upper end of the rear column, and the outer side of the two front columns are fixedly mounted on the outer side. When the rear ladder is rotated to a 180-degree angle with the front ladder, the limiting hook is hooked onto the limiting pin, and at the same time, the back of the front column is rotatably mounted on the outer side of the rear column.

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