Air resistance slow descending structure of extension ladder

Abstract

The utility model provides an extension ladder air resistance slow descent structure which comprises a slow descent structure body, the slow descent structure body comprises a static ventilation structure and a dynamic sealing structure, the dynamic sealing structure comprises an annular sealing element and an axial limiting guide structure, and the axial limiting guide structure comprises a first limiting part and a second limiting part. The inner wall of the ladder tube is suitable for driving the annular sealing element to axially move in the axial limiting and guiding structure in a limited manner through friction force; the first limiting part is continuously matched with the corresponding stage of ladder pipe to form a dynamic first limiting area, the annular sealing element is in interference fit with the first limiting area to form sealed connection, the second limiting part is continuously matched with the corresponding stage of ladder pipe to form a dynamic second limiting area, and the annular sealing element is in clearance fit with the second limiting area. The annular sealing element in the dynamic sealing structure is matched with the first limiting area and the second limiting area under different working conditions, so that sealing and slow descending during contraction are achieved, and ventilation is opened during stretching.

Description

Technical Field

[0001] This utility model relates to the technical field of ladders, specifically to a telescopic ladder air resistance slow-descent structure. Background Technology

[0002] Telescopic ladders are essential for climbing operations; they can be extended and retracted for storage. A typical telescopic ladder consists of two ladder posts and several steps. The ladder posts are made up of interconnected ladder tubes. Current telescopic ladder technology presents safety hazards during use. When the user pushes a button to unlock the ladder, it retracts step by step under its own weight. Traditional telescopic ladders have very low resistance between each step tube, resulting in very rapid retraction. If the user operates improperly and places their hand in the middle of the ladder, the sudden descent can cause injury due to insufficient reaction time. Utility Model Content

[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a telescopic ladder air resistance slow descent structure, which aims to solve the problems of excessively fast descent speed when the telescopic ladder is retracted and the safety hazards of manually operating the retraction switch, so as to meet the needs of users.

[0004] To achieve the above objectives, this utility model provides a telescopic ladder air resistance slow-descent structure, including a slow-descent structure body. The slow-descent structure body is adapted to move synchronously axially within the lower ladder tube under the drive of the current ladder tube. The slow-descent structure body includes...

[0005] A static ventilation structure suitable for connecting the upper ladder pipe and the lower ladder pipe;

[0006] A dynamic sealing structure includes an annular sealing element and an axial limiting guide structure. The axial limiting guide structure includes a first limiting part and a second limiting part. The first limiting part is disposed adjacent to the upper ladder tube, wherein:

[0007] The annular sealing element maintains contact with the inner wall of the ladder tube of this stage, and the inner wall of the ladder tube of this stage is adapted to drive the annular sealing element to make limited axial movement within the axial limiting guide structure through friction.

[0008] The first limiting part cooperates with the ladder tube of the same stage to continuously form a dynamic first limiting area, the annular sealing element is interference-fitted with the first limiting area to form a sealed connection, the second limiting part cooperates with the ladder tube of the same stage to continuously form a dynamic second limiting area, and the annular sealing element is clearance-fitted with the second limiting area.

[0009] Preferably, the first limiting part includes an upper insert ring, and the second limiting part includes a lower insert ring. The upper insert ring has a minimum diameter D1, and the lower insert ring has a minimum diameter D2, where D1 > D2.

[0010] Preferably, the first limiting part includes an upper retaining ring, and the second limiting part includes a lower retaining ring; the upper retaining ring and the lower retaining ring are adapted to respectively restrict the annular sealing element from further axial movement relative to the descent structure body.

[0011] Preferably, the lower retaining ring has a plurality of retaining platforms protruding at intervals toward the annular sealing element, the retaining platforms being adapted to support the annular sealing element, and an air gap is formed between the annular sealing element and the lower retaining ring at intervals.

[0012] Preferably, the upper retaining ring and the lower step tube have a first annular air gap, and the lower retaining ring and the lower step tube have a second annular air gap. The dynamic sealing structure includes a first working state and a second working state, wherein:

[0013] When the ladder tube contracts, the annular sealing element is driven upward by the friction of the inner wall of the lower ladder tube to abut against the first limiting part. The annular sealing element and the first limiting area form an interference seal, blocking the first annular air gap. The dynamic sealing structure is in the first working state.

[0014] When the ladder tube is stretched, the annular sealing element is driven to move downward by the friction of the inner wall of the lower ladder tube and abut against the second limiting part. The first annular air gap opens, the annular sealing element and the second limiting area form a clearance fit, the second annular air gap remains open, and the dynamic sealing structure is in the second working state.

[0015] Preferably, the first limiting part and the second limiting part are connected by a straight cylindrical guide part, wherein the diameter of the guide part is D3, D3≤D1.

[0016] Preferably, the second limiting part includes a tapered guide surface, which is adapted to transitionally connect the guide part and the lower insertion ring, and the tapered guide surface is inclined outward from bottom to top at 5° to 25°.

[0017] Preferably, the slow-descent structure body includes a retaining ring, which is fastened or expanded to the lower end of the ladder tube of the same stage, and a sealing ring is provided between the retaining ring and the lower end of the ladder tube of the same stage to achieve a sealed connection.

[0018] Preferably, the slow-descent structure body includes a support base, which is supported inside the axial sliding zone. The support base includes a base plate and a reinforcing rib disposed above the base plate. The static ventilation structure includes a vent hole and a guide tube. The vent hole is opened in the center of the base plate, and the guide tube is disposed above the base plate. The guide tube is adapted to guide airflow into the vent hole.

[0019] Preferably, the diameter of the guide tube is 3-5 times the diameter of the vent hole.

[0020] Preferably, the peripheral wall of the base plate is connected to the axial limiting guide structure, the reinforcing ribs are supported on the periphery of the guide tube, the reinforcing ribs are arranged in a cross shape or radial shape, and part of the insert rings are supported by the reinforcing ribs, which enhances the strength of the support base and also supports the insert rings, thereby improving the overall strength and durability of the slow-descent structure body.

[0021] The beneficial effects of this utility model are:

[0022] 1. The static ventilation structure connects the upper and lower ladder pipes, ensuring smooth airflow during ladder pipe extension and preventing negative pressure from hindering extension; the annular sealing element in the dynamic sealing structure cooperates with the first and second limit zones under different working conditions to achieve a slow sealing descent during contraction and open ventilation during extension, ensuring precise airflow control in both states.

[0023] Second, the upper insert ring of the first limiting part and the lower insert ring of the second limiting part have different diameters, which enables the annular sealing element to achieve reliable sealing or clearance fit in different positions; the upper and lower retaining rings effectively restrict the axial movement of the annular sealing element, ensuring structural stability and sealing reliability.

[0024] Third, the tapered guide surface and the lower insert ring form a progressive deformation guide. When the sealing element moves down, the tapered surface guides its radial release gradually. The stable fit enhances the overall reliability of the dynamic sealing structure, avoids the sealing element from shifting or getting stuck, and ensures that the air resistance reduction structure can operate stably under various working conditions. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the air resistance slow-descent structure of a telescopic ladder according to the present invention;

[0026] Figure 2 A cross-sectional view of a telescopic ladder air resistance slow-descent structure according to this utility model when the ladder tube is stretched;

[0027] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0028] Figure 4A cross-sectional view of a telescopic ladder air resistance slow-descent structure according to this utility model when the ladder tube is retracted;

[0029] Figure 5 for Figure 4 Enlarged view of point B in the middle.

[0030] In the diagram: 1. Base plate; 2. Rubber ring; 3. Vent hole; 4. Lower retaining ring; 5. Retaining platform; 6. Insert ring; 7. Upper insert ring; 8. Lower insert ring; 9. Upper retaining ring; 10. Reinforcing rib structure; 11. Guide tube; 12. Conical guide surface; 13. Guide part; 14. Static ventilation structure; 15. Dynamic sealing structure; 16. Support base; 17. Axial limiting guide structure; 18. First limiting part; 19. Second limiting part; 20. First limiting area; 21. Second limiting area; 22. First annular air gap; 23. Second annular air gap; 24. Vent gap. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0033] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] like Figure 1-5The aforementioned telescopic ladder air-resistance slow-descent structure includes a slow-descent structure body, which comprises a retaining ring 6, a static ventilation structure 14, a dynamic sealing structure 15, and a support base 16. The retaining ring 6 is tightly fitted with the lower end of the ladder tube of its current stage, thereby enabling the slow-descent structure body to move synchronously axially within the lower ladder tube under the drive of the current stage. A sealing ring (not shown in the figure) is provided between the retaining ring 6 and the lower end of the ladder tube of its current stage to achieve a sealed connection. The dynamic sealing structure 15 includes an annular sealing element and an axial limiting guide structure 17. The annular sealing element is a rubber ring 2. In some other embodiments, the annular sealing element may also be a silicone ring. The retaining ring 6 is disposed above the axial limiting guide structure 17. The support base 16 is supported inside the axial sliding area and includes a base plate 1 and reinforcing ribs disposed above the base plate 1. The peripheral wall of the base plate 1 is connected to the axial limiting guide structure 17. The static ventilation structure 14 is suitable for connecting the upper and lower ladder pipes, and includes a vent 3 and a guide tube 11. The vent 3 is located in the center of the base plate 1, and the guide tube 11 is located above the base plate 1, guiding airflow into the vent 3. Reinforcing ribs are supported on the periphery of the guide tube 11, and the reinforcing ribs are arranged radially. Part of the insert ring 6 is supported by the reinforcing ribs, which enhances the strength of the support base 16 and also supports the insert ring 6, improving the overall strength and durability of the descent structure.

[0035] In this embodiment, the axial limiting guide structure 17 includes a first limiting part 18 and a second limiting part 19. The first limiting part 18 is disposed adjacent to the upper step tube, and the rubber ring 2 is in contact with the inner wall of the current step tube. The inner wall of the current step tube is adapted to drive the rubber ring 2 to perform limited axial movement within the axial limiting guide structure through friction. The first limiting part 18 and the current step tube continuously cooperate to form a dynamic first limiting area 20, and the rubber ring 2 and the first limiting area form a sealed connection through an interference fit. The second limiting part 19 and the current step tube continuously cooperate to form a dynamic second limiting area 21, and the rubber ring 2 and the second limiting area 21 are in a clearance fit.

[0036] In this embodiment, the first limiting part 18 includes an upper retaining ring 9 and an upper inserting ring 7 arranged sequentially from top to bottom, and the second limiting part 19 includes a tapered guide surface 12, a lower inserting ring 8, and a lower retaining ring 4 arranged sequentially from top to bottom. The upper inserting ring 7 and the tapered guide surface 12 are connected by a cylindrical guide part 13. The upper inserting ring 7 has a minimum diameter D1, and the lower inserting ring 8 has a minimum diameter D2, where D1 > D2. The guide part 13 has a diameter D3, where D3 = D1. The upper retaining ring 9 and the lower retaining ring 4 are adapted to further restrict the axial movement of the rubber ring 2 relative to the slow-descent structure body. A first annular air gap 22 is formed between the upper retaining ring 9 and the lower step tube, and a second annular air gap 23 is formed between the lower retaining ring 4 and the lower step tube. The lower retaining ring 4 has a plurality of retaining platforms 5 protruding at intervals toward the rubber ring 2. The retaining platforms 5 are adapted to support the annular sealing element, and an air gap 24 is formed between the annular sealing element and the lower retaining ring 4 at intervals. The tapered guide surface 12 is suitable for transitional connection between the guide portion 13 and the lower insert ring 8, and the tapered guide surface 12 is inclined outward at 18° from bottom to top.

[0037] In this embodiment, the dynamic sealing structure 15 includes a first working state and a second working state.

[0038] When the lower ladder tube contracts, the friction between the inner wall of the lower ladder tube and the rubber ring 2 drives it to move towards the first limiting part 18. The rubber ring 2 is pressed into the upper insert ring 7, and its cross-section expands due to radial compression, forming an interference seal with the first limiting area 20, completely blocking the first annular air gap 22, and the dynamic sealing structure 15 is in the first working state. At this time, the air cavity inside the lower ladder tube is connected to the upper ladder tube only through the static ventilation structure 14, namely the guide tube 11 and the vent 3, forming a single confined airflow channel.

[0039] When the ladder tube is stretched, the rubber ring 2 is driven downwards by the friction of the inner wall of the lower ladder tube to the second limiting part 19 and enters the lower insertion ring 8. At this time, the sealing element can provide a larger radial space due to the increased diameter of the lower insertion ring 8 and thus fits with the second limiting area 19 with a clearance. The first annular air gap 22 is open, and the second annular air gap 23 remains open. The dynamic sealing structure 15 is in the second working state, and airflow can flow through both the static ventilation structure 14 and the dynamic sealing structure 15 simultaneously. It is understood that airflow can, but is not limited to, flow to the second annular air gap 23 through the ventilation gap 24. In the second working state, airflow can flow to the second annular air gap 23 through any gap surrounding the rubber ring 2.

[0040] The above embodiments 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model.

Claims

1. A telescopic ladder air resistance slow descent structure, characterized in that, The system includes a deceleration structure body, which is adapted to move synchronously axially within the lower step of the ladder tube under the drive of the current step. The deceleration structure body includes... A static ventilation structure suitable for connecting the upper ladder pipe and the lower ladder pipe; A dynamic sealing structure includes an annular sealing element and an axial limiting guide structure. The axial limiting guide structure includes a first limiting part and a second limiting part. The first limiting part is disposed adjacent to the upper ladder tube, wherein: The annular sealing element maintains contact with the inner wall of the ladder tube of this stage, and the inner wall of the ladder tube of this stage is adapted to drive the annular sealing element to make limited axial movement within the axial limiting guide structure through friction. The first limiting part cooperates with the ladder tube of the same stage to continuously form a dynamic first limiting area, the annular sealing element is interference-fitted with the first limiting area to form a sealed connection, the second limiting part cooperates with the ladder tube of the same stage to continuously form a dynamic second limiting area, and the annular sealing element is clearance-fitted with the second limiting area.

2. The air resistance slow descent structure of an extension ladder according to claim 1, wherein The first limiting part includes an upper insert ring, and the second limiting part includes a lower insert ring. The upper insert ring has a minimum diameter D1, and the lower insert ring has a minimum diameter D2, where D1 > D2.

3. The air resistance slow descent structure of an extension ladder according to claim 2, wherein The first limiting part includes an upper retaining ring, and the second limiting part includes a lower retaining ring; the upper retaining ring and the lower retaining ring are adapted to respectively restrict the annular sealing element from further axial movement relative to the descent structure body.

4. The air-hammering slow descending structure of an extendable ladder according to claim 3, wherein, The lower retaining ring has several retaining platforms protruding at intervals toward the annular sealing element. The retaining platforms are adapted to support the annular sealing element, and an air gap is formed between the annular sealing element and the lower retaining ring at intervals.

5. The air-hammering slow descent structure of an extension ladder according to claim 3 or 4, characterized in that, A first annular air gap exists between the upper retaining ring and the lower step tube, and a second annular air gap exists between the lower retaining ring and the lower step tube. The dynamic sealing structure includes a first working state and a second working state, wherein: When the ladder tube contracts, the annular sealing element is driven upward by the friction of the inner wall of the lower ladder tube to abut against the first limiting part. The annular sealing element and the first limiting area form an interference seal, blocking the first annular air gap. The dynamic sealing structure is in the first working state. When the ladder tube is stretched, the annular sealing element is driven to move downward by the friction of the inner wall of the lower ladder tube and abut against the second limiting part. The first annular air gap opens, the annular sealing element and the second limiting area form a clearance fit, the second annular air gap remains open, and the dynamic sealing structure is in the second working state.

6. The air-hammering slow descending structure of an extendable ladder according to claim 5, wherein, The first limiting part and the second limiting part are connected by a straight cylindrical guide part, wherein the diameter of the guide part is D3, and D3≤D1.

7. The air-hammering slow descent structure of an extension ladder according to claim 6, wherein, The second limiting part includes a tapered guide surface, which is adapted to transitionally connect the guide part and the lower insertion ring. The tapered guide surface is inclined outward from bottom to top at 5° to 25°.

8. The air-hammering slow descending structure of an extendable ladder according to claim 1, wherein, The slow-descent structure body includes a plug ring, which is fastened or expanded to the lower end of the ladder tube of the same stage, and a sealing ring is provided between the plug ring and the lower end of the ladder tube of the same stage to achieve a sealed connection.

9. The air-hammering slow descent structure of an extension ladder according to claim 8, wherein, The slow-descent structure body includes a support base, which is supported inside the axial sliding zone. The support base includes a base plate and a reinforcing rib disposed above the base plate. The static ventilation structure includes a vent hole and a guide tube. The vent hole is opened in the center of the base plate, and the guide tube is disposed above the base plate. The guide tube is adapted to guide airflow into the vent hole.

10. The air-hammering slow descent structure of an extension ladder according to claim 9, wherein, The peripheral wall of the base plate is connected to the axial limiting guide structure, the reinforcing ribs are supported on the periphery of the guide tube, and the reinforcing ribs are arranged in a cross shape or radial shape, with part of the insertion ring being supported by the reinforcing ribs.

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