ladder

Abstract

The application discloses a ladder which can be conveniently walked, positioned and switched, comprising two first supporting ladder poles arranged in parallel, a plurality of steps arranged between the two first supporting ladder poles, two second supporting ladder poles arranged in parallel, a plurality of transverse connecting rods arranged between the two second supporting ladder poles, a ladder foot arranged at the lower end of at least one of the first supporting ladder poles and the second supporting ladder poles, wherein the ladder foot comprises a main casing used for connecting the lower end of the supporting ladder pole, the lower end of the main casing is provided with an anti-skid part, a moving wheel arranged at one side of the main casing, the moving wheel can be operated to move along a straight line direction between a first position and a second position which is higher than the first position, when the moving wheel is located at the first position, the lowest point of the moving wheel is lower than the anti-skid part, so that the moving wheel provides support, when the moving wheel is located at the second position, the moving wheel is higher than the anti-skid part, so that the anti-skid part provides support.

Description

Technical Field

[0001] This application relates to a ladder. Background Technology

[0002] Ladders are commonly used to improve access to locations that may not be directly accessible to their users. Ladders come in many shapes and sizes, such as straight ladders, extended ladders, and combination ladders and telescopic ladders (referred to here as combination ladders). Combination ladders incorporate many advantages of other ladder designs into a single ladder, as they can be used as adjustable step stools or extended ladders.

[0003] Because engineering combination ladders consist of two ladders, one inside and one outside, and have a lot of steps, they are quite heavy and difficult to move. For example, the ladder disclosed in US10501990B2 has wheels installed at the feet of the ladder to facilitate movement. The process of using this ladder is as follows: when the site conditions are limited and it is not possible to reach the required distance by simply operating on the ladder, the added wheels are put down to allow the ladder to move back and forth. After moving, the wheels can be put back in the working state and the ladder can be used normally.

[0004] However, the wheels on the modular ladder in this project need to be rotated to be raised and lowered. The switching operation requires a large space, making it difficult to switch states when in a corner. Furthermore, when the wheels are lowered to support the ladder, manual assistance is required to lift the ladder and then lower the wheels, making the operation complicated and increasing the workload of manual labor. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, one object of the present invention is to provide a ladder that can facilitate switching between a normal state and a moving state.

[0006] One object of the present invention is to provide a switchable ladder leg and a ladder having the ladder leg, so as to reduce the space required for switching operations.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A ladder, comprising:

[0009] Two first support ladder rods are arranged in parallel, and multiple steps are provided between the two first support ladder rods;

[0010] Two parallel second support ladder rods are provided, and multiple transverse connecting rods are provided between the two second support ladder rods;

[0011] Ladder feet are disposed at the lower end of at least one of the first and second support ladder rods, the ladder feet comprising:

[0012] The main housing is connected to the lower end of the support ladder rod, and the lower end of the main housing is provided with an anti-slip part;

[0013] A movable wheel is disposed on one side of the main housing. The movable wheel can be manipulated to move along a straight line in a first position and a second position above the first position. When the movable wheel is in the first position, the lowest point of the movable wheel is lower than the anti-slip part so that the movable wheel provides support. When the movable wheel is in the second position, it is higher than the anti-slip part so that the anti-slip part provides support.

[0014] As a preferred embodiment, the ladder is an aluminum ladder or a fiberglass ladder, which includes a combination ladder.

[0015] A ladder leg, comprising:

[0016] The main housing is used to connect the lower end of the support ladder rod, and the lower end of the main housing is provided with an anti-slip part;

[0017] A movable wheel is disposed on one side of the main housing. The movable wheel can be operatively moved to a first position and a second position above the first position. When the movable wheel is in the first position, the lowest point of the movable wheel is lower than the anti-slip part so that the movable wheel provides support. When the movable wheel is in the second position, it is higher than the anti-slip part so that the anti-slip part provides support.

[0018] As a preferred embodiment, the movable wheel is configured to be operatively switched between a first position and a second position in a vertical direction.

[0019] As a preferred embodiment, the main housing has a receiving body on one side; the receiving body has a cavity with a downward opening; a linkage is provided in the cavity, and the movable wheel is rotatably connected to the lower end of the linkage; the linkage is restricted to slide up and down in the cavity, thereby driving the movable wheel to switch between a first position and a second position;

[0020] The main housing is provided with an operating component; the operating component is connected to the linkage body via a linkage shaft; the operating component can rotate around the central axis of the linkage shaft;

[0021] The control member has a first control position corresponding to the first position and a second control position corresponding to the second position; the control member has a force-applying part for receiving applied force, and the control member generates an action by applying force, switching between the first control position and the second control position, thereby driving the moving wheel to switch between the first position and the second position; when the control member switches from the first control position to the second control position, it rotates around the central axis and lifts the linkage shaft.

[0022] In a preferred embodiment, the actuator has a first positioning plane and a second positioning plane arranged at an angle of 60 to 120 degrees.

[0023] A limiting platform is fixed on one side of the main housing; the operating member rotates around the central axis to switch between contact and positioning of the first positioning plane and the second positioning plane with the limiting platform; when the operating member is in the first operating position, the first positioning plane is in contact and positioned with the limiting platform; when the operating member is in the second operating position, the second positioning plane is in contact and positioned with the limiting platform; the distance between the linkage shaft and the limiting platform is a variable distance, which is greater when the second positioning plane is in contact and positioned with the limiting platform than when the first positioning plane is in contact and positioned with the limiting platform.

[0024] In a preferred embodiment, the control element includes a control handle and a cam plate disposed at one end of the control handle; the first positioning plane and the second positioning plane are adjacent perpendicular side surfaces of the cam plate; the linkage shaft passes through the cam plate; the distance between the linkage shaft and the first positioning plane is less than the distance between the linkage shaft and the second positioning plane.

[0025] In a preferred embodiment, the limiting platform is fixedly disposed on one side of the accommodating body; the lower opening of the accommodating body is higher than the lower end face of the anti-slip part.

[0026] As a preferred embodiment, the accommodating body is further provided with an elastic element that applies a downward elastic force to the linkage body.

[0027] In a preferred embodiment, the linkage has a wheel housing cavity for accommodating the movable wheel and an upward-opening spring housing cavity; the elastic element is a cylindrical spring housed within the spring housing cavity; the cylindrical spring is compressed between the bottom wall of the spring housing cavity and the top wall of the housing.

[0028] As a preferred embodiment, the upper end of the linkage body is provided with two spring-loaded cavities arranged side by side; multiple reinforcing plates are provided between the cavity walls of the two spring-loaded cavities; the two opposite side walls of the linkage body are provided with long grooves; and the multiple reinforcing plates are located between the two long grooves.

[0029] The movable wheel is rotatably connected to the linkage body via an axle; the linkage body is provided with an axle hole through which the axle passes; the axle hole is located at the lower end of the long groove; the long groove extends downward from the upper end of the linkage body to the axle hole.

[0030] As a preferred embodiment, the two opposite sidewalls of the accommodating body are respectively provided with guide elongated holes; the linkage shaft passes through the guide elongated holes and moves up and down along the guide elongated holes. Beneficial effects

[0031] The ladder of the present invention can quickly switch between a moving state and a fixed state. No disassembly is required when switching between the moving and fixed states, which is convenient for management and less likely to be lost. Furthermore, the ladder foot structure used in this embodiment is reliable, easy to operate, and occupies little space.

[0032] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0033] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0034] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a three-dimensional structural diagram of a ladder provided in one embodiment of the present invention;

[0037] Figure 2 yes Figure 1 A diagram showing the state of the ladder legs when the ladder is in a moving state;

[0038] Figure 3 yes Figure 1 A schematic diagram showing the state of the ladder legs when the ladder is in the positioning state;

[0039] Figure 4 yes Figure 1 Exploded view of the ladder legs;

[0040] Figure 5 yes Figure 4 Another three-dimensional structural diagram;

[0041] Figure 6 yes Figure 4 Another view;

[0042] Figure 7 yes Figure 4 Another view;

[0043] Figure 8 yes Figure 4 Schematic diagram of the limiting platform;

[0044] Figure 9 yes Figure 4 A schematic diagram of the linkage and control mechanism.

[0045] Figure 10 yes Figure 4 A schematic diagram of another mating structure between the linkage and the control component;

[0046] Figure 11 yes Figure 4 Front view of the control component.

[0047] 1. Bolt; 2. Casters; 3. Axle; 4. Linkage mechanism; 5. Control mechanism; 6. Main housing; 7. Linkage shaft; 8. Cylindrical spring; 100. First support ladder rod; 150. Second support ladder rod; 155. Lateral connecting rod; 200. Step; 500. Ladder feet;

[0048] 42. Reinforcing plate; 45. Long groove;

[0049] 51. Control handle; 52. Cam plate; 521. First positioning plane; 522. Second positioning plane; 523. Transition arc surface;

[0050] 61. Main cavity; 611. Connecting protrusion; 62. Receiving body; 623. Guide elongated hole; 625. Top wall; 65. Anti-slip part; 651. Anti-slip texture; 67. Additional body; 671. Limiting platform; Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0052] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0054] like Figures 1 to 11 One embodiment of this application provides a ladder, which is an aluminum ladder or a fiberglass ladder. This ladder can be adapted to modular ladders such as engineering modular ladders, and of course, it can also be used as a household ladder. Figures 1 to 3 As shown, the ladder includes: two first supporting ladder rods 100 arranged in parallel; two second supporting ladder rods 150 arranged in parallel; and ladder feet 500 disposed at the lower end of at least one of the first supporting ladder rods 100 and the second supporting ladder rods 150. Multiple steps 200 are provided between the two first supporting ladder rods 100; multiple transverse connecting rods 155 are provided between the two second supporting ladder rods 150. Both the two first supporting ladder rods 100 and the two second supporting ladder rods 150 can be hollow aluminum rods, and the steps 200 and transverse connecting rods 155 can also be made of aluminum, thereby reducing the overall weight of the ladder and facilitating movement.

[0055] like Figure 2 , Figure 3 As shown, each of the two first support ladder rods 100 and the two second support ladder rods 150 is equipped with ladder feet 500, and the movement or positioning of the ladder as a whole is achieved through state switching. Of course, in other embodiments, the two first support ladder rods 100 and the two second support ladder rods 150 may only be equipped with one, two, or three ladder feet 500 as in this embodiment, and positioning may be achieved by one, two, or three ladder feet 500. The other ladder feet can be ordinary anti-slip mats or ordinary rollers.

[0056] In this embodiment, the ladder feet 500 can also be referred to as foot shells. The ladder feet 500 in this embodiment include: a main housing 6 for connecting and supporting the ladder rods (100 / 150), and a caster 2 disposed on one side of the main housing 6. The lower end of the main housing 6 is provided with an anti-slip part 65. The anti-slip part 65 can be an anti-slip pad fixed to the lower end of the main housing 6, with anti-slip texture 651 on its lower end surface, and can be adhesively fixed to the lower end of the main housing 6.

[0057] In this embodiment, the movable wheel 2 can be manipulated to move in a first position and a second position higher than the first position. Both the first and second positions can be referenced to the main housing 6 or the anti-slip part 65. When the movable wheel 2 is in the first position, its lowest point is lower than the anti-slip part 65, providing support; when the movable wheel 2 is in the second position, it is higher than the anti-slip part 65, providing support. The movable wheel 2 is configured to be manipulated to switch between the first and second positions along a vertical (straight line) direction. The movable wheel 2 translates between the first and second positions. The vertical movement path of the movable wheel 2 is a straight line, not a curved or zigzag path, making the movement simple, convenient, and structurally reliable. This straight line direction is generally vertical, specifically the length direction of the supporting ladder rod where the ladder foot 500 is located. Because it moves with the supporting ladder rod, this straight line direction may sometimes be vertical and sometimes oblique, depending on the state of the supporting ladder rod.

[0058] In this embodiment, the movable wheel 2 of the ladder foot 500 has two positions, one up and one down, when switching states. The movable wheel 2 does not need to rotate or swing, but can switch between the first and second positions by simply moving up and down in a straight line, thus requiring no large operating space.

[0059] When using a ladder with the ladder legs 500, if the front-to-back distance cannot meet the specified requirements, the moving wheels 2 can be lowered to the first position, and the anti-slip part 65 can be suspended in the air, allowing the ladder to move back and forth by rolling the moving wheels 2. After the movement is completed, the moving wheels 2 can be switched to the second position, the anti-slip part 65 can contact the ground, the ladder can return to normal, and then the ladder can be used normally.

[0060] The ladder legs 500 and the ladder having the ladder legs 500 in this embodiment can quickly realize the ladder. Figure 2 The movement state shown is the same as Figure 3 The switching between the positioning states shown does not require disassembly, making it easy to manage and less prone to loss. Furthermore, the ladder feet 500 in this embodiment have a reliable structure, are easy to operate, and occupy little space.

[0061] A receiving body 62 is provided on one side of the main housing 6. The cross-sectional area of ​​the receiving body 62 is smaller than that of the main housing 6, and the main housing 6 and the receiving body 62 can be integrally formed. The receiving body 62 has a cavity with an opening facing downwards, and the upper end of the cavity is sealed by a top wall 625. A linkage 4 is provided inside the cavity, and the movable wheel 2 is rotatably connected to the lower end of the linkage 4; the linkage 4 is restricted to sliding up and down in the vertical direction within the cavity, thereby driving the movable wheel 2 to switch between a first position and a second position.

[0062] The main housing 6 has a main sidewall surrounding the main cavity 61, and symmetrically arranged connecting protrusions 611 are provided inside the main cavity 61. The two ends of the main sidewall are respectively connected to two opposing short sidewalls of the accommodating body 62, and the linkage shaft 7 passes through the two opposing long sidewalls. The lower end of the main sidewall is connected to the main bottom wall, and the anti-slip part 65 is fixedly installed on the bottom side of the main bottom wall. Between the main bottom wall and the main sidewall, there are multiple outer reinforcing ribs located outside the main cavity 61 and multiple inner reinforcing ribs located inside the main cavity 61. The main bottom plate has a flange-like structure supported on the lower end of the main sidewall, with its outer edge located outside the main sidewall and extending to connect with the outer wall of the accommodating body 62.

[0063] In this embodiment, the main housing 6 is provided with a force-applying actuating member 5. The actuating member 5 is connected to the linkage body 4 via a linkage shaft 7. The actuating member 5 can rotate around the central axis of the linkage shaft 7; wherein, the central axis is a horizontal axis, which is perpendicular to the direction of movement of the linkage body 4.

[0064] The control member 5 has a first control position corresponding to the first position and a second control position corresponding to the second position. The control member 5 has a force-applying part for receiving applied force. The control member 5 generates an action by applying force, switching between the first control position and the second control position, thereby driving the moving wheel 2 to switch between the first position and the second position.

[0065] Specifically, by pressing down the control element 5, it is switched from the first control position to the second control position, and the moving wheel 2 is raised and retracted. When it is necessary to move the ladder and lower the moving wheel 2, the operator manually lifts the control element 5, and the elastic element can assist in applying force to the linkage 4, switching the control element 5 from the first control position to the second control position, which is convenient for manual operation.

[0066] The linkage shaft 7 and the linkage body 4 rise or fall together. When the operating element 5 switches from the first operating position to the second operating position, it rotates around the central axis and raises the linkage shaft 7. When the operating element 5 switches to the first operating position, it is positioned in the first operating position by its own structure; when it switches to the second operating position, it is positioned in the second operating position by its own structure.

[0067] like Figures 4-11 As shown, the operating member 5 has a first positioning plane 521 and a second positioning plane 522 arranged at an angle. A limiting platform 671 is fixedly provided on one side of the main housing 6. An additional body 67 is provided on one side of the main housing 6. This additional body 67 can be an integral structure with the main housing 6. The limiting platform 671 is a planar structure disposed on the additional body 67. The operating member 5 rotates around the central axis, causing the first positioning plane 521 and the second positioning plane 522 to alternately contact and position with the limiting platform 671. The included angle is 60 to 120 degrees. Figure 7As shown, the angle between the first positioning plane 521 and the second positioning plane 522 is 90 degrees. At this time, the first positioning plane 521 and the second positioning plane 522 are perpendicular to each other, so that the positioning of the control member 5 is stable when it switches to the first control position or the second control position.

[0068] When the operating element 5 is in the first operating position, the first positioning plane 521 contacts and is positioned with the limiting platform 671. At this time, the position of the operating element 5 is as follows: Figure 2 and Figure 10 As shown. Press down the control element 5 to... Figure 3 As shown in the second operating position, when the operating member 5 is in the second operating position, the second positioning plane 522 is in contact with the limiting platform 671 for positioning; the distance between the linkage shaft 7 and the limiting platform 671 is a variable distance, which is greater when the second positioning plane 522 is in contact with the limiting platform 671 for positioning than when the first positioning plane 521 is in contact with the limiting platform 671 for positioning.

[0069] To ensure both ease of operation and stable positioning, and to prevent unintended positional shifts after switching to the desired position, the vertical distance between the central axis and the second positioning plane 522 is at least 1.5 times the vertical distance between the central axis and the first positioning plane 521. More preferably, the vertical distance between the central axis and the second positioning plane 522 is between 2 times and 4 times the vertical distance between the central axis and the first positioning plane 521. Even more preferably, the vertical distance between the central axis and the second positioning plane 522 is between 2.5 times and 3.5 times the vertical distance between the central axis and the first positioning plane 521. Let L2 be the vertical distance between the central axis and the second positioning plane 522, and L1 be the vertical distance between the central axis and the first positioning plane 521, where L2 ≥ 1.5 * L1. Further, 4 * L1 ≥ L2 ≥ 2 * L1, and even more preferably, 3.5 * L1 ≥ L2 ≥ 2.5 * L1.

[0070] To facilitate switching of the control element 5 between the first control position and the second control position, a transition arc surface 523 is provided between the first positioning plane 521 and the second positioning plane 522, such as... Figure 10 , Figure 11 As shown, the transition arc surface 523 is a quarter-circle arc. When the moving wheel 2 carries the ladder, the linkage shaft 7 applies force to the cam plate 52, forming an upward rotational torque on the cam plate 52. This torque is further increased, especially when other heavy objects are being carried. To prevent the operating element 5 from automatically switching positions under the influence of this torque, the length L3 of the first positioning plane 521 is greater than the radius of the transition arc surface 523, and the length L3 of the first positioning plane 521 is greater than the vertical distance L1 between the central axis and the first positioning plane 521.

[0071] It should be noted that any numerical value described herein includes all values, both lower and upper, increasing by one unit from the lower limit to the upper limit, with at least a two-unit interval between any lower and any higher value. For example, if the value of a component quantity or process variable (such as the aforementioned angle) is described as being from 60 to 120 degrees, preferably from 70 to 110 degrees, and more preferably from 80 to 100 degrees, the purpose is to illustrate that values ​​such as 65 to 85, 88 to 111, 72 to 101, and 79 to 95 are also explicitly listed in this specification. These are merely examples intended for clarity, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are similarly explicitly described in this specification. Furthermore, unless otherwise stated, all ranges include the endpoints and all numbers between the endpoints.

[0072] The control element 5 is a plate-and-buckle structure, which cannot spontaneously switch between the first and second control positions. The control element 5 requires operator force to switch between the first and second control positions. Specifically, for ease of operation, the control element 5 includes a control handle 51 and a cam plate 52 disposed at one end of the control handle 51; the first positioning plane 521 and the second positioning plane 522 are adjacent perpendicular side surfaces of the cam plate 52; the linkage shaft 7 passes through the cam plate 52. The distance between the linkage shaft 7 and the first positioning plane 521 is less than its distance from the second positioning plane 522. The limiting platform 671 is fixedly disposed on one side of the accommodating body 62.

[0073] From the perspective of the vertical projection on the plane where the first positioning plane 521 is located, the control handle 51 and the linkage shaft 7 are located on both sides of the transition arc surface 523 respectively. When the force is applied to the control member 5, the control member 5 rotates through the transition arc surface 523 as a support point, so that the control member 5 can smoothly switch between the first control position and the second control position.

[0074] The lower opening of the accommodating body 62 is higher than the lower end face of the anti-slip part 65. The accommodating body 62 is also provided with an elastic element, which applies a downward elastic force to the linkage body 4. The linkage body 4 has a wheel mounting cavity for accommodating the moving wheel 2 and an upward-facing spring cavity; the elastic element is a cylindrical spring 8 housed in the spring cavity; the cylindrical spring 8 is compressed between the bottom wall of the spring cavity and the top wall 625 of the accommodating body 62.

[0075] The elastic element applies a force to the linkage 4, moving it toward the first position, thereby preventing the moving wheels 2 of the ladder feet 500 from moving undesirably during ladder use and maintaining the ladder's stable movement. In conjunction with the aforementioned limitation on the length L3 of the first positioning plane 521, the foot shell of this embodiment further prevents the operating element 5 from lifting itself while supported by the moving wheels 2 by providing an elastic element, ensuring smooth ladder movement.

[0076] The upper end of the linkage body 4 has two spring-collecting cavities arranged side by side. Multiple reinforcing plates 42 are provided between the cavity walls of the two spring-collecting cavities. Two cylindrical springs 8 are respectively housed within the two spring-collecting cavities, jointly applying force to the linkage body 4. The two opposite sidewalls of the linkage body 4 have elongated grooves 45; multiple reinforcing plates 42 are located between the two elongated grooves 45. The multiple reinforcing plates 42 are located above the linkage shaft 7 to enhance the structural strength of the linkage body 4 above the linkage shaft 7.

[0077] The movable wheel 2 is rotatably connected to the linkage body 4 via an axle 3; the linkage body 4 is provided with an axle hole through which the axle 3 passes; the axle hole is located at the lower end of the elongated groove 45. The elongated groove 45 extends downward from the upper end of the linkage body 4 to the axle hole.

[0078] The accommodating body 62 has two opposite sidewalls with guide holes 623. The guide holes 623 are located outside the elongated groove 45, and their positions are roughly corresponding, extending in the same direction, both vertically. The linkage shaft 7 passes through the guide holes 623 and moves vertically along them. Fixed bolts are threaded to both ends of the linkage shaft 7. The linkage shaft 7 passes through the cam plate 52, the linkage body 4, and the accommodating body 62, and intercepts the fixed bolts at both ends. The upper end of the guide holes 623 is covered and blocked by the top wall 625 of the accommodating body 62.

[0079] Instructions for use: When the location meets the work requirements and the ladder does not need to be moved, step on the control 5 to retract the casters 2, ensuring the ladder feet 500 are in stable contact with the ground. The ladder is then positioned and ready for normal use. If the ladder needs to be moved due to work requirements, lift the control 5 to lower the casters 2. The ladder in its unloaded state can then be pushed forward and backward.

[0080] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of the main body content, nor should it be construed as the inventor failing to consider that subject matter as part of the disclosed inventive subject matter.

Claims

1. A ladder, characterized in that, include: Two first support ladder rods are arranged in parallel, and multiple steps are provided between the two first support ladder rods; Two parallel second support ladder rods are provided, and multiple transverse connecting rods are provided between the two second support ladder rods; Ladder feet are disposed at the lower end of at least one of the first and second support ladder rods, the ladder feet comprising: The main housing is connected to the lower end of the support ladder rod, and the lower end of the main housing is provided with an anti-slip part; A movable wheel is disposed on one side of the main housing. The movable wheel can be operatively moved along a straight line to a first position and a second position above the first position. When the movable wheel is in the first position, the lowest point of the movable wheel is lower than the anti-slip part so that the movable wheel provides support. When the movable wheel is in the second position, it is higher than the anti-slip part so that the anti-slip part provides support. The main housing has a receiving body on one side; the main housing and the receiving body are integrally formed; the receiving body has a cavity with an opening facing downward; a linkage body is provided in the cavity, and the movable wheel is rotatably connected to the lower end of the linkage body; the linkage body is restricted to slide up and down in the cavity, thereby driving the movable wheel to switch between a first position and a second position. The main housing is provided with an operating component; the operating component is connected to the linkage body via a linkage shaft; the operating component can rotate around the central axis of the linkage shaft; The control member has a first control position corresponding to the first position and a second control position corresponding to the second position; the control member has a force-applying part for receiving applied force, and the control member generates an action by applying force, switching between the first control position and the second control position, thereby driving the moving wheel to switch between the first position and the second position; when the control member switches from the first control position to the second control position, it rotates around the central axis and lifts the linkage shaft.

2. The ladder as described in claim 1, characterized in that, The ladder is an aluminum ladder or a fiberglass ladder, and includes combination ladders.

3. The ladder as described in claim 2, characterized in that, The control element has a first positioning plane and a second positioning plane arranged at an angle of 60 to 120 degrees. A limiting platform is fixed on one side of the main housing; the operating member rotates around the central axis to switch between contacting and positioning the first positioning plane and the second positioning plane with the limiting platform; when the operating member is in the first operating position, the first positioning plane contacts and positions with the limiting platform. When the control element is in the second control position, the second positioning plane contacts and positions itself with the limiting table. The distance between the linkage shaft and the limiting platform is a variable distance. This variable distance is greater when the second positioning plane contacts and positions the limiting platform than when the first positioning plane contacts and positions the limiting platform.

4. The ladder as described in claim 3, characterized in that, The control element includes a control handle and a cam plate disposed at one end of the control handle; the first positioning plane and the second positioning plane are adjacent perpendicular side surfaces of the cam plate; the linkage shaft passes through the cam plate; the distance between the linkage shaft and the first positioning plane is less than the distance between the linkage shaft and the second positioning plane.

5. The ladder as described in claim 4, characterized in that, The limiting platform is fixedly disposed on one side of the accommodating body; the lower opening of the accommodating body is higher than the lower end face of the anti-slip part.

6. The ladder as described in claim 3, characterized in that, The accommodating body is also provided with an elastic element, which applies a downward elastic force to the linkage body.

7. The ladder as described in claim 5, characterized in that, The linkage has a wheel housing cavity for accommodating the movable wheel and an upward-opening spring housing cavity; the elastic element is a cylindrical spring housed in the spring housing cavity; the cylindrical spring is compressed between the bottom wall of the spring housing cavity and the top wall of the housing.

8. The ladder as described in claim 7, characterized in that, The upper end of the linkage body is provided with two spring cavities arranged side by side; multiple reinforcing plates are provided between the cavity walls of the two spring cavities; long grooves are provided on the two opposite side walls of the linkage body; multiple reinforcing plates are located between the two long grooves; The movable wheel is rotatably connected to the linkage body via an axle; the linkage body is provided with an axle hole through which the axle passes; the axle hole is located at the lower end of the long groove; the long groove extends downward from the upper end of the linkage body to the axle hole.

9. The ladder as described in claim 4, characterized in that, The two opposite sidewalls of the accommodating body are respectively provided with guide holes; the linkage shaft passes through the guide holes and moves up and down along the guide holes.

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