Ladder angle adjustment device and ladder

Abstract

The utility model provides a kind of ladder frame angle adjusting device and ladder, it is related to ladder technical field, the ladder frame angle adjusting device includes universal rotation ladder foot and angle adjusting mechanism;Universal rotation ladder foot includes support frame, ball hinge connecting piece and base;Ball hinge connecting piece upper end is connected with the lower end of support frame;Base is connected with the lower end of ball hinge connecting piece by spherical surface rotary pair rotation;Angle adjusting mechanism includes first connecting piece, second connecting piece and rotary positioning structure;First connecting piece is used to connect with original ladder frame lower end;Second connecting piece lower end is connected with the upper end of support frame and is oppositely arranged with first connecting piece;Rotary positioning structure is used to adjust and lock the relative rotation angle of first connecting piece and second connecting piece along the opposite surface of two opposites.Ladder frame of ladder has two upright column lower end respectively connected with one aforementioned ladder frame angle adjusting device.The utility model solves the technical problem that ladder cannot be adapted to complex terrain environment such as slope and step surface in prior art.

Description

Technical Field

[0001] This utility model relates to the field of ladder technology, and in particular to a ladder frame angle adjustment device and a ladder. Background Technology

[0002] Ladders, as common tools for working at heights, are widely used in building maintenance, home renovation, and industrial repair. Traditional ladders typically consist of two parallel uprights and several rungs, with their structural design based on horizontal ground conditions. However, with the diversification of applications, ladders increasingly need to adapt to slopes, steps, and other non-planar terrain.

[0003] In the existing technology, the two uprights of the ladder frame are connected at a fixed angle, which cannot be independently adjusted according to the slope of the ground. It can only be used safely on flat ground and cannot be applied to sloping or stepped ground, thus limiting the application range of the ladder in complex terrain environments. Utility Model Content

[0004] The purpose of this utility model is to provide a ladder frame angle adjustment device and ladder fixture to solve the technical problem that existing ladder fixtures cannot adapt to complex terrain environments such as inclined surfaces and stepped surfaces.

[0005] To achieve the above objectives, the embodiments of this utility model adopt the following technical solutions: In a first aspect, this utility model provides a ladder frame angle adjustment device, which includes a universal rotating ladder foot and an angle adjustment mechanism; The universal swivel ladder legs include: Support frame; The ball joint connector is fixedly connected to the lower end of the support frame at its upper end or is integrally formed therefrom; The base is rotatably connected to the lower end of the ball joint connector via a spherical revolute joint; The angle adjustment mechanism includes: The first connector is used to fix the lower end of the original ladder frame of the ladder. The lower end of the second connector is fixedly connected to the upper end of the support frame or integrally formed thereon, and one end of the second connector is disposed opposite to one end of the first connector and can rotate along their opposite surfaces. A rotary positioning structure is provided between the first connector and the second connector to adjust and lock the relative rotation angle between the first connector and the second connector along their opposing surfaces.

[0006] In an optional embodiment, the rotary positioning structure includes a spring, a bolt, and a nut knob; The first connector and the second connector each have a ring of meshing teeth arranged circumferentially along their relative rotation direction on their opposing surfaces. The bolt includes a polygonal head and a threaded portion. The threaded portion passes through the first connector and the second connector and is connected to the nut knob. The polygonal head and the nut knob are respectively located on opposite sides of the first connector and the second connector, and the polygonal head is positioned in a polygonal positioning groove provided on the first connector or the second connector. The spring is sleeved on the outer periphery of the screw portion and clamped between the first connector and the second connector. In the locked state, the spring is axially compressed and the meshing teeth of the first connector and the meshing teeth of the second connector mesh with each other. By rotating the nut knob relative to the bolt, the spring is axially compressed or released, thereby controlling the engagement or disengagement of the meshing teeth of the first connector and the second connector, and thus adjusting and locking the relative rotation angle between the first connector and the second connector.

[0007] In an optional embodiment, the first connector and the second connector are respectively provided with receiving grooves on their opposing surfaces, the meshing teeth are arranged around the receiving grooves, the spring is disposed inside the receiving grooves, and the two ends of the spring abut against the inner sidewall of the receiving groove of the corresponding connector.

[0008] In an optional embodiment, the opposing surfaces of the first connector and the second connector are respectively concave surfaces. The recessed surface of the first connector is located at the lower end of the first connector and extends to the lower edge of the first connector. The upper side surface of the first connector forms a first stepped surface. The recessed surface of the second connector is located at the upper end of the second connector and extends to the upper edge of the second connector. The second connector forms a second stepped surface on the lower end side surface of its recessed surface. The upper end face of the second connector is in contact with the first step surface, and the lower end face of the first connector is in contact with the second step surface.

[0009] In an optional embodiment, the lower end of the ball joint connector is provided with a ball head, and the upper surface of the base is provided with a ball head groove that is adapted to the ball head. The ball head is accommodated in the ball head groove, and the two cooperate to form the spherical rotating pair.

[0010] In an optional embodiment, the base includes a first housing and a second housing that are interlocked with each other. The opposite sidewalls of the first housing and the second housing are respectively provided with grooves, and the grooves of the two housings cooperate to form the ball head groove.

[0011] In an optional embodiment, the bottom surface of the base is provided with an anti-slip structure.

[0012] In an optional embodiment, the anti-slip structure is an anti-slip texture integrally formed on the base.

[0013] In an optional embodiment, the anti-slip structure is a rubber pad fixedly connected to the bottom surface of the base.

[0014] Secondly, this utility model provides a ladder, which includes a ladder frame and two uprights. The lower end of each upright is provided with a ladder frame angle adjustment device provided in any of the optional embodiments of the first aspect. In each ladder frame angle adjustment device, the first connecting member is fixedly connected to the lower end of the corresponding upright.

[0015] The embodiments of this utility model can achieve at least the following beneficial effects: The ladder frame angle adjustment device provided in this embodiment improves the adaptability and stability of the ladder in complex terrains such as slopes and steps by introducing universal rotating ladder feet and an angle adjustment mechanism.

[0016] Specifically, the omnidirectional swivel ladder foot includes a support frame, a ball joint connector, and a base. The upper end of the ball joint connector is fixedly connected to the lower end of the support frame or integrally formed, and the base is rotatably connected to the lower end of the ball joint connector via a spherical revolute joint. This design allows the base to rotate freely in three-dimensional space, thus adapting to various irregular surfaces, such as inclined, uneven, or even stepped surfaces. When the ladder is placed on these complex surfaces, the base can automatically conform to the ground, effectively avoiding single-sided suspension or localized stress concentration, thereby significantly improving the overall stability and safety of the ladder. The angle adjustment mechanism includes a first connecting member, a second connecting member, and a rotary positioning structure. The first connecting member is fixedly connected to the lower end of the existing ladder frame. The lower end of the second connecting member is fixedly connected to the upper end of the support frame or integrally formed, and one end of the second connecting member is positioned opposite to one end of the first connecting member and can rotate along their opposing surfaces. The rotary positioning structure is located between the first and second connecting members and is used to adjust and lock the relative rotation angle between the first and second connecting members along their opposing surfaces. This design allows users to flexibly adjust the posture of the ladder legs in three-dimensional space according to the actual working scenario, and to accurately position and securely lock them at any set angle. When the ladder is placed on sloping, uneven, or even stepped ground, the support height of the two uprights connected to the ladder frame can be adjusted individually to ensure that the lower ends of the two uprights are at the same height. This not only ensures the overall balance and stability of the ladder but also avoids problems such as one side being suspended or localized stress concentration. The self-adjusting fitting function of the base effectively prevents the ladder from being suspended on one side during use, reducing the risk of tipping over due to this. By independently adjusting the support height, the stress on the ladder can be evenly distributed, avoiding localized stress concentration, thereby improving the ladder's load-bearing capacity and service life.

[0017] In addition, this utility model embodiment also provides several optional implementation methods. The specific implementation method section of this specification will provide a detailed description and explanation of the specific structure and functional effects of these optional implementation methods. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the overall structure of the ladder frame angle adjustment device provided in this embodiment of the utility model; Figure 2 An exploded view of the overall structure of the ladder frame angle adjustment device provided in this embodiment of the utility model; Figure 3 A side view of the overall structure of the ladder frame angle adjustment device provided in this embodiment of the utility model; Figure 4 for Figure 3 Sectional view along axis AA; Figure 5 A schematic diagram illustrating the application scenario of the ladder provided in this embodiment of the utility model on an inclined plane; Figure 6 A schematic diagram illustrating the application scenario of the ladder provided in this embodiment of the utility model on a step surface.

[0020] Icon: 100 - Ladder frame angle adjustment device; 1-Universal swivel step; 11-Support frame; 12-Spherical hinge connector; 121-Ball head; 13-Base; 131-First housing; 132-Second housing; 1301-Ball head groove; 2-Angle adjustment mechanism; 21-First connecting piece; 211-First stepped surface; 22-Second connecting piece; 221-Second stepped surface; 23-Rotary positioning structure; 231-Spring; 232-Bolt; 2321-Polygonal head; 2322-Screw part; 233-Nut knob; 24-Meshing teeth; 25-Receiving groove; 3-Glue pad; 200 - Ladder frame; 210 - Column. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that similar labels and letters in the accompanying drawings indicate similar items. Therefore, once an item is defined in one accompanying drawing, it does not need to be further defined and explained in subsequent accompanying drawings.

[0024] In the description of this utility model, it should be noted that the terms "upper," "lower," "vertical," "horizontal," "inner," and "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 commonly used when the utility model product is in 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. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] First aspect This embodiment provides a ladder frame angle adjustment device 100, referring to... Figures 1 to 4 The ladder frame angle adjustment device 100 includes a universal rotating ladder foot 1 and an angle adjustment mechanism 2.

[0028] Specifically, the omnidirectional swivel ladder foot 1 includes a support frame 11, a ball joint connector 12, and a base 13; the upper end of the ball joint connector 12 is fixedly connected to the lower end of the support frame 11 or integrally formed; the base 13 is rotatably connected to the lower end of the ball joint connector 12 through a spherical revolute joint. The angle adjustment mechanism 2 includes a first connector 21, a second connector 22, and a rotation positioning structure 23; the first connector 21 is fixedly connected to the lower end of the original ladder frame 200 of the ladder; the lower end of the second connector 22 is fixedly connected to the upper end of the support frame 11 or integrally formed, and one end of the second connector 22 is opposite to one end of the first connector 21 and can rotate along their opposite surfaces; the rotation positioning structure 23 is located between the first connector 21 and the second connector 22 and is used to adjust and lock the relative rotation angle of the first connector 21 and the second connector 22 along their opposite surfaces.

[0029] Reference Figure 5 and Figure 6 The ladder frame angle adjustment device 100 is applied to a ladder. Specifically, the ladder includes a ladder frame 200, which includes two uprights 210. The lower end of each upright 210 is provided with a ladder frame angle adjustment device 100 provided in any optional embodiment of the first aspect. In each ladder frame angle adjustment device 100, the first connecting member 21 is fixedly connected to the lower end of the corresponding upright 210. The fixed connection method includes, but is not limited to, the corresponding connecting member and the lower end of the corresponding upright 210 being fitted together with an interference fit, or being fixed by any fixing member such as a bolt and nut assembly, rivet, pin, screw, etc., or the corresponding connecting member and the lower end of the corresponding upright 210 being directly welded or bonded, or the two being attached together and then directly fixed by any fixing member such as a bolt and nut assembly, rivet, pin, screw, etc., or fixedly connected in other ways.

[0030] The ladder frame angle adjustment device 100 provided in this embodiment improves the adaptability and stability of the ladder in complex terrains such as slopes and steps by introducing a universal rotating ladder foot 1 and an angle adjustment mechanism 2.

[0031] Specifically, the omnidirectional swivel ladder foot 1 includes a support frame 11, a ball joint connector 12, and a base 13. The upper end of the ball joint connector 12 is fixedly connected to the lower end of the support frame 11 or integrally formed, and the base 13 is rotatably connected to the lower end of the ball joint connector 12 through a spherical revolute joint. This design allows the base 13 to rotate freely in three-dimensional space, thus adapting to various irregular surfaces, such as inclined, uneven, or even stepped surfaces. When the ladder is placed on these complex surfaces, the base 13 can automatically conform to the ground, effectively avoiding single-sided suspension or localized stress concentration, thereby significantly improving the overall stability and safety of the ladder. The angle adjustment mechanism 2 includes a first connecting member 21, a second connecting member 22, and a rotation positioning structure 23. The first connecting member 21 is fixedly connected to the lower end of the existing ladder frame 200 of the ladder. The lower end of the second connecting member 22 is fixedly connected to the upper end of the support frame 11 or integrally formed therein. One end of the second connecting member 22 is positioned opposite to one end of the first connecting member 21 and can rotate along their opposing surfaces. The rotation positioning structure 23 is located between the first connecting member 21 and the second connecting member 22, and is used to adjust and lock the relative rotation angle between the first connecting member 21 and the second connecting member 22 along their opposing surfaces. This design allows users to flexibly adjust the posture of the ladder legs in three-dimensional space according to the actual working scenario, and to accurately position and securely lock them at any set angle. When the ladder is placed on sloping, uneven, or even stepped ground, the support height of the support frame 11 connected to the two uprights 210 of the ladder frame 200 can be adjusted to keep the lower ends of the two uprights 210 at the same height. This not only ensures the overall balance and stability of the ladder but also avoids problems such as one-sided suspension or localized stress concentration. The self-adjusting fitting function of the base 13 effectively prevents the ladder from being suspended on one side during use, reducing the risk of tipping over due to this. By independently adjusting the support height, the force on the ladder can be evenly distributed, avoiding localized stress concentration, thereby improving the load-bearing capacity and service life of the ladder.

[0032] In summary, the ladder frame angle adjustment device 100 provided in this embodiment not only enables the ladder to adapt to complex terrain but also provides flexible and precise angle adjustment. This design significantly improves the stability and safety of the ladder when used on uneven or sloping ground, while also offering good ease of operation and versatility, making it suitable for various working environments.

[0033] In some optional embodiments of this example, the rotary positioning structure 23 includes a spring 231, a bolt 232, and a nut knob 233. The opposing surfaces of the first connecting member 21 and the second connecting member 22 are respectively provided with a ring of meshing teeth 24 arranged circumferentially along their relative rotational direction. The bolt 232 includes a polygonal head 2321 and a threaded portion 2322. The threaded portion 2322 passes through the first connecting member 21 and the second connecting member 22 and connects to the nut knob 233. The polygonal head 2321 and the nut knob 233 are respectively located on opposite sides of the first connecting member 21 and the second connecting member 22, and the polygonal head 2321 is positioned within a polygonal positioning groove provided on the first connecting member 21 or the second connecting member 22. Spring 231 is sleeved on the outer periphery of screw portion 2322 and clamped between first connector 21 and second connector 22. In the locked state, spring 231 is axially compressed and the meshing teeth 24 of first connector 21 and second connector 22 mesh with each other. By rotating nut knob 233 relative to bolt 232, spring 231 is axially compressed or released, thereby controlling the meshing teeth 24 of first connector 21 and second connector 22 to mesh or disengage, thereby adjusting and locking the relative rotation angle between first connector 21 and second connector 22.

[0034] In some alternative embodiments of this example, "bolt knob and nut" replaces the above-mentioned "bolt 232 and nut knob 233" (not shown). In this alternative embodiment, the bolt knob includes a knob part and a screw part. The screw part passes through the first connector 21 and the second connector 22 and is connected to the nut. The knob part and the nut are respectively located on opposite sides of the first connector 21 and the second connector 22. The outer contour of the cross-section of the nut is polygonal and the nut is positioned in a polygonal positioning groove provided on the first connector 21 or the second connector 22. By rotating the knob part of the bolt knob relative to the nut, the spring 231 is axially compressed or released, thereby controlling the meshing teeth 24 of the first connector 21 and the second connector 22 to mesh or separate, thereby adjusting and locking the relative rotation angle between the first connector 21 and the second connector 22.

[0035] The above optional embodiments provide a specific structural design for locking and unlocking the first connector 21 and the second connector 22 using a rotary positioning structure 23. Under this structure, the user can precisely adjust and lock the relative rotation angle between the first connector 21 and the second connector 22. In the locked state, the spring 231 is axially compressed, causing the meshing teeth 24 of the first connector 21 and the second connector 22 to mesh with each other, forming a firm lock. This improves the stability and safety of the ladder when used on uneven or inclined surfaces. At the same time, the adjustment process is simple and convenient, allowing for quick operation by the user.

[0036] In an optional embodiment of this example, the first connector 21 and the second connector 22 are respectively provided with receiving grooves 25 on their opposing surfaces, the meshing teeth 24 are arranged around the receiving grooves 25, and the spring 231 is provided inside the receiving grooves 25, with the two ends of the spring 231 abutting against the inner sidewall of the receiving groove 25 of the corresponding connector. In this optional embodiment, by providing receiving grooves 25 on the first connector 21 and the second connector 22 and placing the spring 231 therein, with both ends of the spring 231 abutting against the inner sidewall of the receiving groove 25, the entire rotary positioning structure 23 becomes more compact. The receiving groove 25 provides limiting space for the spring 231, ensuring the stable positioning of the spring 231 during compression and release, preventing the spring 231 from shifting or dislodging during use, thereby improving the reliability of the rotary positioning structure 23. At the same time, the spring 231 is located inside the receiving groove 25. Compared to floating the spring 231 on the opposite surface of the first connector 21 and the second connector 22, the meshing teeth 24 of the first connector 21 and the second connector 22 can mesh more tightly in the locked state, thereby enhancing the locking effect and further ensuring the stability of the ladder in various complex terrains and working environments.

[0037] In an optional embodiment of this example, the opposing surfaces of the first connector 21 and the second connector 22 are respectively concave surfaces. The concave surface of the first connector 21 is located at the lower end of the first connector 21 and extends to the lower edge of the first connector 21. A first step surface 211 is formed on the upper side surface of the concave surface of the first connector 21. The concave surface of the second connector 22 is located at the upper end of the second connector 22 and extends to the upper edge of the second connector 22. A second step surface 221 is formed on the lower side surface of the concave surface of the second connector 22. The upper end surface of the second connector 22 is in contact with the first step surface 211, and the lower end surface of the first connector 21 is in contact with the second step surface 221. In this optional embodiment, the mutual fitting design of the first step surface 211 and the second step surface 221 provides a clear assembly reference, making the assembly process more precise and simple. Users can easily align the two connectors to ensure that they are locked at the correct angle and position, improving the consistency and reliability of the assembly. At the same time, the design of the recessed surface and the step surface makes the connection between the first connector 21 and the second connector 22 smoother and more compact, enhancing the aesthetic appearance of the entire ladder frame angle adjustment device 100 and improving the user experience.

[0038] In addition, in an optional embodiment of this example, in the structure in which "the lower end of the base 13 and the ball joint connector 12 are rotatably connected by a spherical revolute pair", preferably, the lower end of the ball joint connector 12 is provided with a ball head 121, and the upper surface of the base 13 is provided with a ball head groove 1301 adapted to the ball head 121. The ball head 121 is accommodated in the ball head groove 1301, and the two cooperate to form the aforementioned spherical revolute pair.

[0039] For ease of assembly, further optional, such as Figure 2 As shown, the base 13 includes a first housing 131 and a second housing 132 that interlock with each other. The opposite sidewalls of the first housing 131 and the second housing 132 are respectively provided with grooves, and the grooves of the two housings cooperate to form a ball head groove 1301. The fixing method of the first housing 131 and the second housing 132 after interlocking with each other includes, but is not limited to, snap-fit ​​connection or fixing connection by screws, bolt and nut assemblies, rivets, pins or other fixing connectors.

[0040] To further enhance the stability of the ladder during use, in an optional embodiment of this invention, the bottom surface of the base 13 is provided with an anti-slip structure. In some specific optional embodiments, the anti-slip structure is an anti-slip texture integrally formed on the base 13; in other specific optional embodiments, the anti-slip structure is a rubber pad 3 fixedly connected to the bottom surface of the base 13. The fixed connection method includes, but is not limited to, bonding or fixing with screws or bolt-nut assemblies or other fixed connectors. The rubber pad 3 may be made of rubber, but is not limited to, and its bottom surface may be further provided with anti-slip texture to further enhance the anti-slip effect.

[0041] Second aspect This embodiment also provides a ladder, as shown in the reference. Figure 5 and Figure 6 The ladder includes a ladder frame 200, which includes two uprights 210. The lower end of each upright 210 is provided with a ladder frame angle adjustment device 100 provided in any optional embodiment of the first aspect. In each of the ladder frame angle adjustment devices 100, the first connecting member 21 is fixedly connected to the lower end of the corresponding upright 210. The fixed connection method includes, but is not limited to, the corresponding connecting member and the lower end of the corresponding upright 210 being fitted together with an interference fit, or being fixed by any fixing member such as a bolt and nut assembly, rivet, pin, screw, etc., or the corresponding connecting member and the lower end of the corresponding upright 210 being directly welded or bonded, or the two being attached together and then directly fixed by any fixing member such as a bolt and nut assembly, rivet, pin, screw, etc., or fixedly connected in other ways.

[0042] The specific structure and achievable effects of the ladder provided in this embodiment can be obtained by referring to the optional or preferred embodiments in the first aspect.

[0043] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above embodiments in this specification are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of this utility model.

Claims

1. A ladder frame angle adjustment device, characterized in that, It includes omnidirectional rotating ladder feet (1) and angle adjustment mechanism (2); The universal swivel step (1) includes: Support frame (11); The upper end of the ball joint connector (12) is fixedly connected to the lower end of the support frame (11) or integrally formed; The base (13) is rotatably connected to the lower end of the ball joint connector (12) via a spherical revolute joint; The angle adjustment mechanism (2) includes: The first connector (21) is used to fix the lower end of the original ladder frame (200) of the ladder. The lower end of the second connector (22) is fixedly connected to the upper end of the support frame (11) or integrally formed, and one end of the second connector (22) is opposite to one end of the first connector (21) and can rotate along their opposite surfaces. A rotation positioning structure (23) is provided between the first connector (21) and the second connector (22) for adjusting and locking the relative rotation angle of the first connector (21) and the second connector (22) along their opposite surfaces.

2. The ladder frame angle adjustment device according to claim 1, characterized in that, The rotary positioning structure (23) includes a spring (231), a bolt (232), and a nut knob (233). The first connector (21) and the second connector (22) are respectively provided with a ring of meshing teeth (24) arranged circumferentially along their relative rotation direction on their opposite surfaces. The bolt (232) includes a polygonal head (2321) and a threaded portion (2322). The threaded portion (2322) passes through the first connector (21) and the second connector (22) and is connected to the nut knob (233). The polygonal head (2321) and the nut knob (233) are respectively located on opposite sides of the first connector (21) and the second connector (22). The polygonal head (2321) is positioned in a polygonal positioning groove provided on the first connector (21) or the second connector (22). The spring (231) is sleeved on the outer periphery of the screw part (2322) and sandwiched between the first connector (21) and the second connector (22). In the locked state, the spring (231) is axially compressed and the meshing teeth (24) of the first connector (21) and the meshing teeth (24) of the second connector (22) mesh with each other. By rotating the nut knob (233) relative to the bolt (232) to axially compress or release the spring (231), the meshing teeth (24) of the first connector (21) and the second connector (22) are controlled to mesh or separate, thereby adjusting and locking the relative rotation angle between the first connector (21) and the second connector (22).

3. The ladder frame angle adjustment device according to claim 2, characterized in that, The first connector (21) and the second connector (22) are respectively provided with receiving grooves (25) on their opposite surfaces. The meshing teeth (24) are arranged around the receiving grooves (25). The spring (231) is located inside the receiving grooves (25). The two ends of the spring (231) abut against the inner sidewall of the receiving groove (25) of the corresponding connector.

4. The ladder frame angle adjustment device according to claim 2, characterized in that, The opposing surfaces of the first connector (21) and the second connector (22) are concave surfaces, respectively. The recessed surface of the first connector (21) is located at the lower end of the first connector (21) and extends to the lower edge of the first connector (21). The first connector (21) forms a first stepped surface (211) on the upper side surface of its recessed surface. The recessed surface of the second connector (22) is located at the upper end of the second connector (22) and extends to the upper edge of the second connector (22). The second connector (22) forms a second step surface (221) on the lower side surface of its recessed surface. The upper end face of the second connector (22) is in contact with the first step surface (211), and the lower end face of the first connector (21) is in contact with the second step surface (221).

5. The ladder frame angle adjustment device according to claim 1, characterized in that, The lower end of the ball joint connector (12) is provided with a ball head (121), and the upper surface of the base (13) is provided with a ball head groove (1301) that is adapted to the ball head (121). The ball head (121) is housed in the ball head groove (1301), and the two cooperate to form the spherical rotating pair.

6. The ladder frame angle adjustment device according to claim 5, characterized in that, The base (13) includes a first housing (131) and a second housing (132) that are interlocked with each other. The opposite side walls of the first housing (131) and the second housing (132) are respectively provided with grooves, and the grooves of the two housings cooperate to form the ball head groove (1301).

7. The ladder frame angle adjustment device according to claim 1, characterized in that, The bottom surface of the base (13) is provided with an anti-slip structure.

8. The ladder frame angle adjustment device according to claim 7, characterized in that, The anti-slip structure is an anti-slip texture integrally formed on the base (13).

9. The ladder frame angle adjustment device according to claim 7, characterized in that, The anti-slip structure is a rubber pad (3) fixedly connected to the bottom surface of the base (13).

10. A ladder, characterized in that, The system includes a ladder frame (200), which includes two columns (210). Each column (210) has a ladder frame angle adjustment device (100) as described in any one of claims 1 to 9 at its lower end. In each ladder frame angle adjustment device (100), the first connecting member (21) is fixedly connected to the lower end of the corresponding column (210).

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