Stretching and contracting mechanism for telescopic tube

Abstract

This invention relates to the field of connecting device technology, and in particular to a flexible tension-contraction mechanism for a telescopic tube. The flexible tension-contraction mechanism for a telescopic tube, disposed within the telescopic tube, includes an upper plate, a middle plate, and a lower plate arranged sequentially from top to bottom. The upper plate and the middle plate are fixedly connected by a connector. A column extending from the middle plate is provided at the lower part of the upper plate, and a connector is fixed to the bottom of the column. The lower plate passes through the column and is confined between the middle plate and the connector. When the telescopic tube is compressed, the lower plate moves upward relative to the middle plate to its closest point to the middle plate. When the telescopic tube is extended, the lower plate moves downward relative to the middle plate to its furthest point from the middle plate. This invention provides a flexible tension-contraction mechanism for a telescopic rod that not only reduces the contraction speed during contraction but also makes extension very easy and convenient.

Description

Technical Field

[0001] This invention relates to the field of connection device technology, and in particular to a flexible tension-contraction mechanism for a telescopic tube. Background Technology

[0002] A connecting device is generally needed between two relatively telescopic rods (pipes) to connect the two rods (pipes) and allow them to stretch or contract relative to each other. For example, in products such as telescopic table legs, chair legs, and telescopic ladders, the connecting device plays a crucial role.

[0003] In particular, telescopic ladders are ladders that can be extended and shortened like a fishing rod. They are very convenient to carry and store, and can be placed in closets, studies, under beds, or car trunks. Because ladders are products with high requirements for safety and sturdiness, the connecting device between the telescopic rods of a telescopic ladder not only determines the ladder's telescopic performance, but also its safety and sturdiness during use.

[0004] For example, the technical content disclosed in Chinese patent CN102733751B is as follows: a safety telescopic ladder with anti-pinch function, comprising two vertically arranged ladder rods, each ladder rod being composed of multiple telescopically connected sections, each section having a cover at its lower opening, the cover having a small cylindrical part and a large cylindrical part located below the small cylindrical part, the small cylindrical part of the cover being inserted into and fixed to the lower opening of the section, the large cylindrical part of the cover protruding downwards and outwards from the corresponding section and located within the adjacent lower section, the outer circumferential surface of the large cylindrical part having an annular groove, the lower side wall of the annular groove having an axially penetrating vent hole, a sealing ring being provided in the annular groove, the sealing ring being able to slide up and down within the annular groove, and the sealing ring always being in contact with the inner wall of the adjacent lower section, forming a sliding fit.

[0005] The aforementioned prior art provides a safety telescopic ladder that slows down the ladder's retraction speed to prevent finger pinching. By reducing the speed at which the ladder descends and retracts, it aims to prevent injury to the user's fingers and eliminate safety hazards. However, due to its structural design, it generally requires considerable force to pull the ladder up for use, making it very difficult for younger users or those with less strength. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a flexible telescopic rod extension and contraction mechanism that not only reduces the contraction speed during contraction but also makes extension very easy and convenient. To solve the above-mentioned technical problems, this invention provides the following technical solution:

[0007] A flexible tensioning and contraction mechanism for a telescopic tube is provided inside the telescopic tube. The mechanism includes an upper plate, a middle plate, and a lower plate arranged sequentially from top to bottom. The upper plate and the middle plate are fixedly connected by a connector. The lower part of the upper plate is provided with a column extending out of the middle plate. A connector is fixed to the bottom of the column. The lower plate passes through the column and is confined between the middle plate and the connector.

[0008] When the telescopic tube is compressed, the lower plate moves upward relative to the middle plate to the position closest to the middle plate.

[0009] When the telescopic tube is stretched, the lower plate moves downward relative to the middle plate to the point furthest from the middle plate.

[0010] Specifically, the telescopic tube includes an inner tube with a smaller diameter and an outer tube with a larger diameter that fit together. The stretching and shrinking softening mechanism is located at the bottom of the inner tube and inside the outer tube. The size of the stretching and shrinking softening mechanism is designed and adjusted according to the diameter of the inner tube and the outer tube, and it has a variety of sizes.

[0011] Based on the above technical solutions, the present invention can also adopt the following further technical solutions:

[0012] The upper plate also includes an upper plate body, and the column is located at the lower part of the upper plate body; the column includes an integrally formed upper column and a lower column, the upper column is a cylindrical structure, and the lower column is a trapezoidal conical structure with a diameter gradually decreasing from top to bottom; the lower part of the upper plate body is also provided with a fixing column.

[0013] The height of the upper column is equal to or greater than the thickness of the middle plate, and the height of the lower column is greater than the thickness of the lower plate.

[0014] The middle plate includes a middle plate body, which has a first column hole and a fixing hole. When the upper plate is fixedly connected to the middle plate, the upper column passes through the first column hole and is surrounded by the first column hole. The height of the upper column is equal to or greater than the height of the first column hole. The connecting piece passes through the fixing hole from the lower part of the middle plate and is threadedly connected to the fixing column at the lower part of the upper plate.

[0015] The perimeter of the middle plate is surrounded by a barrier.

[0016] The lower plate includes a lower plate body, which has a second column hole. When the lower plate is confined between the middle plate and the connecting member, the lower column body passes through the second column hole and is surrounded by the second column hole. The height of the lower column body is greater than the height of the second column hole.

[0017] The second post hole is a trapezoidal conical hole with a diameter that gradually decreases from top to bottom. The taper of the second post hole is the same as the taper of the lower post. The maximum diameter of the second post hole is less than or equal to the maximum diameter of the upper post.

[0018] The lower plate body is provided with a buffer ring on its outer periphery, which is made of flexible material; the lower plate body is provided with a vent hole; the lower surface of the lower plate body is provided with a boss, which is located at the edge of the lower opening of the second column hole.

[0019] The upper surface of the lower plate is also provided with a movable cavity. When the lower plate is confined between the middle plate and the connecting piece, the fixing column of the upper plate moves within the movable cavity as the lower plate is displaced.

[0020] The head of the connector is provided with a limiting piece. When the lower plate moves downward relative to the middle plate to the position furthest from the middle plate, the limiting piece abuts against the boss.

[0021] Compared with the prior art, the beneficial effects that this invention can achieve are:

[0022] When the stretching and contraction mitigation mechanism of this invention is installed on a telescopic tube (rod), especially on a telescopic ladder, when the telescopic tube is stretched, the lower plate and the middle plate separate, and a gap is formed between the second column hole and the lower column body. External air can enter the outer tube through this gap, making stretching easy and convenient. When the telescopic tube is compressed, the lower plate is close to the middle plate, which closes the gap between the second column hole and the lower column body, blocking most of the air passage. Air in the outer tube can only be slowly discharged through the vent hole, thereby achieving a speed reduction effect between the tubes during compression. When used on a telescopic ladder, it can achieve the functions of slow descent and anti-pinch. Attached Figure Description

[0023] Figure 1 This is an exploded top view of a telescopic tube stretching and contraction smoothing mechanism according to the present invention.

[0024] Figure 2 This is an exploded view from a low angle of view of a telescopic tube stretching and contraction smoothing mechanism according to the present invention.

[0025] Figure 3 This is a schematic diagram of a ladder structure, representing a fifth embodiment of the flexible stretching and contraction mechanism for a telescopic tube according to the present invention.

[0026] Figure 4 This is a cross-sectional view of the ladder compression state connection point in Embodiment 5 of the flexible tension and contraction mechanism of the telescopic tube of the present invention.

[0027] Figure 5 This is a cross-sectional view of the ladder tension connection in embodiment five of the flexible tension and contraction mechanism of the telescopic tube of the present invention.

[0028] Among them, the upper plate 1, the upper plate body 11, the upper column 12, the lower column 13, the fixed column 14, the first reinforcing rib 15, the middle plate 2, the middle plate body 21, the first column hole 22, the fixing hole 23, the step 24, the enclosure 25, the second reinforcing rib 26, the lower plate 3, the lower plate body 31, the second column hole 32, the buffer ring 33, the vent hole 34, the boss 35, the movable cavity 36, the third reinforcing rib 37, the connector 4, the limiting piece 41, and the telescopic ladder 5. Implementation

[0029] The following description, in conjunction with the accompanying drawings, further illustrates the stretching and contraction easing mechanism for a telescopic tube provided by the present invention.

[0030] Example 1, as Figure 1-2 As shown, a stretching and contraction mitigation mechanism for a telescopic tube is provided inside the telescopic tube. The telescopic tube includes an inner tube with a smaller diameter and an outer tube with a larger diameter that fit together. The stretching and contraction mitigation mechanism is located at the bottom of the inner tube and placed inside the outer tube.

[0031] The aforementioned mechanism includes an upper plate 1, a middle plate 2, and a lower plate 3 arranged sequentially from top to bottom. The upper plate 1 and the middle plate 2 are located inside the lower end of the inner tube and are fixed with an interference fit to the lower end of the inner tube. The lower plate 3 is movably sleeved on the column of the upper plate 1, and the outer periphery of the lower plate 3 contacts and abuts against the inner wall of the outer tube.

[0032] Specifically, the upper plate 1 and the middle plate 2 are fixedly connected by a connector 4. The lower part of the upper plate 1 is provided with three columns extending out of the middle plate 2. Each column is also fixed with a connector 4 at its bottom. The lower plate 3 passes through the columns and is confined between the middle plate 2 and the connector 4.

[0033] Furthermore, the upper plate 1 also includes an upper plate body 11, with three pillars located at the lower part of the upper plate body 11. Each of the three pillars includes an integrally formed upper pillar 12 and a lower pillar 13. The upper pillar 12 is a cylindrical structure, and the lower pillar 13 is a trapezoidal conical structure with a diameter that gradually decreases from top to bottom.

[0034] Furthermore, a fixed column 14 is provided at the lower part of the upper plate body 11. A first reinforcing rib 15 is provided between the fixed column 14 and each column to increase the flatness of the upper plate body 11 and the perpendicularity between the three columns, the fixed column 14 and the upper plate body 11.

[0035] Furthermore, the height of the upper column 12 is equal to or greater than the thickness of the middle plate 2, and the height of the lower column 13 is greater than the thickness of the lower plate 3.

[0036] The middle plate 2 includes a middle plate body 21, which has three first column holes 22 and one fixing hole 23. When the upper plate 1 is fixedly connected to the middle plate 2, each upper column 12 passes through each first column hole 22 in a corresponding manner and is surrounded by the first column hole 22. The height of the upper column 12 is equal to or greater than the height of the first column hole 22.

[0037] Furthermore, a second reinforcing rib 26 is provided between each first column hole 22 and the fixing hole 23 to increase the flatness of the middle plate body 21 and the perpendicularity of the three first column holes 22, fixing holes 23 and the middle plate body 21.

[0038] Furthermore, a connector 4 passes through the fixing hole 23 from the lower part of the middle plate 2 and is threadedly connected to the fixing post 14 at the lower part of the upper plate 1. The lower surface of the middle plate 21 is provided with a step 24 at the edge of the fixing hole 23. When the connector 4 and the fixing post 14 are fixed together, the head of the connector 4 presses against the step 24 to limit the movement.

[0039] Furthermore, a retaining wall 25 is provided around the perimeter of the middle plate 2. The retaining wall 25 surrounds the three first column holes 22 and one fixing hole 23 to provide protection. When the upper plate 1 and the middle plate 2 are fixed, the retaining wall 25 contacts and presses against the lower surface of the upper plate 1 to provide a sealing effect.

[0040] The lower plate 3 includes a lower plate body 31, which has three second column holes 32. When the lower plate 3 is confined between the middle plate 2 and the connecting member 4, each lower column 13 passes through each second column hole 32 in a corresponding manner and is surrounded by the second column hole 32.

[0041] Furthermore, the height of the lower column 13 is greater than the height of the second column hole 32.

[0042] Furthermore, the second column hole 32 is a trapezoidal conical hole with a diameter that gradually decreases from top to bottom. The taper of the second column hole 32 is the same as the taper of the lower column 13, and the maximum diameter of the second column hole 32 is less than or equal to the diameter of the upper column 12, so as to limit the upward movement range of the lower plate 3.

[0043] Furthermore, a buffer ring 33 is provided on the outer periphery of the lower plate body 31. The buffer ring 33 is made of flexible material and contacts and abuts against the inner wall of the outer tube.

[0044] Furthermore, the lower plate body 31 is provided with a vent hole 34, the function of which is to allow air to be discharged.

[0045] Furthermore, the lower surface of the lower plate 31 is provided with a boss 35, which is located at the edge of the lower opening of the second column hole 32. The head of the connector 4 is provided with a limiting piece 41. When the lower plate 3 moves downward relative to the middle plate 2 to the position furthest away from the middle plate 2, the limiting piece 41 abuts against the boss 35.

[0046] Furthermore, the upper surface of the lower plate 31 is provided with a movable cavity 36. When the lower plate 3 is confined between the middle plate 2 and the connecting member 4, the fixing post 14 of the upper plate 1 moves within the movable cavity 36 as the lower plate 3 is displaced. A third reinforcing rib 37 is provided between the movable cavity 36 and each of the second post holes 32 to increase the flatness of the lower plate 31 and the perpendicularity of the three second post holes 32, the movable cavity 36, and the lower plate 31.

[0047] When the telescopic tube is stretched, the lower plate 3 moves downward relative to the middle plate 2 to the position furthest away from the middle plate 2, and the lower plate 3 and the middle plate 2 separate. A gap is formed between the second column hole 32 and the lower column 13. External air can enter the outer tube through this gap and then through the gap between the bosses. Thus, the air inside the outer tube and the air outside form a flow channel. At the same time as stretching, a sufficient amount of air enters the outer tube from the outside, eliminating the suction force during stretching, making stretching easy and convenient.

[0048] When the telescopic tube is compressed, the lower plate 3 moves upward relative to the middle plate 2 to the position closest to the middle plate 2, thereby sealing the gap between the second column hole 32 and the lower column 13, blocking most of the air passage. The air in the outer tube can only be slowly discharged through the small-diameter vent hole 34, thus achieving the speed reduction effect between the tubes during compression. When used on a telescopic ladder, it can achieve the functions of slow descent and anti-pinch.

[0049] Example 2, as Figure 1-2 As shown, the fixing post 14 has internal threads, and the connector 4 is a screw with external threads. The connector 4 and the fixing post 14 are connected by threads. Everything else is the same as in Embodiment 1.

[0050] In Embodiment 3, the fixing post 14 is hollow, and the connector 4 is inserted into the hollow part of the fixing post 14 so that the connector 4 and the fixing post 14 are connected and fixed. Everything else is the same as in Embodiment 1.

[0051] Example 4, as Figure 2 As shown, there are twelve bosses 35, with four bosses 35 at the edge of the lower opening of each second post hole 32. The bosses 35 are evenly spaced to ensure that the limiting piece 41 can be uniformly limited. Everything else is the same as in Embodiment 1.

[0052] Example 5, such as Figure 3-5As shown, a stretching and contraction mitigation mechanism for telescopic tubes is provided at the connection points of each telescopic tube in the telescopic ladder 5. Each set of relatively telescopic tubes includes an inner tube with a smaller diameter and an outer tube with a larger diameter that fit together. The stretching and contraction mitigation mechanism is located at the bottom of the inner tube and placed inside the outer tube. The diameter of each stretching and contraction mitigation mechanism is determined according to the diameter of the inner and outer tubes in which it is located; that is, the telescopic ladder has multiple stretching and contraction mitigation mechanisms with different diameters.

[0053] Specifically, when the stretching and contraction mitigation mechanism is applied to a 60mm outer diameter pipe, the telescopic ladder implemented using the existing technology CN102733751B requires a pulling force of 100N to extend, while the telescopic ladder implemented using this embodiment only requires a pulling force of 20N to extend. Compared with the existing technology, the telescopic ladder of this embodiment consumes only one-fifth of the pulling force, demonstrating a significantly more efficient labor-saving effect.

[0054] in, Figure 5 The arrows in the diagram indicate the airflow channels. Everything else is the same as in Example 1.

[0055] The present invention has been illustrated and described with reference to preferred embodiments; however, those skilled in the art will understand that various changes in form and detail may be made within the scope of the claims.

Claims

1. A flexible tensioning and contraction mechanism for a telescopic tube, disposed within the telescopic tube, characterized in that... The mechanism includes an upper plate, a middle plate, and a lower plate arranged sequentially from top to bottom. The upper plate and the middle plate are fixedly connected by a connector. The lower part of the upper plate has a column extending out of the middle plate. The bottom of the column is fixed with a connector. The lower plate passes through the column and is confined between the middle plate and the connector. The upper plate also includes an upper plate body, and the column is located at the lower part of the upper plate body. The column includes an integrally formed upper column and a lower column. The upper column is a cylindrical structure, and the lower column is a trapezoidal conical structure with a diameter gradually decreasing from top to bottom. The lower part of the upper plate body is also provided with a fixing column. The lower plate includes a lower plate body, and the lower plate body has a second column hole. When the lower plate is confined between the middle plate and the connector, the lower column passes through the second column hole and is surrounded by the second column hole. The height of the lower column is greater than the height of the second column hole. When the telescopic tube is compressed, the lower plate moves upward relative to the middle plate to the position closest to the middle plate. When the telescopic tube is stretched, the lower plate moves downward relative to the middle plate to the point furthest from the middle plate. The upper surface of the lower plate is also provided with a movable cavity. When the lower plate is confined between the middle plate and the connecting piece, the fixing column of the upper plate moves within the movable cavity as the lower plate is displaced.

2. A stretch-retraction flex mechanism for a retractable tube according to claim 1, wherein The height of the upper column is equal to or greater than the thickness of the middle plate, and the height of the lower column is greater than the thickness of the lower plate.

3. A stretch-retraction mechanism for a retractable tube according to claim 1, wherein The middle plate includes a middle plate body, which has a first column hole and a fixing hole. When the upper plate is fixedly connected to the middle plate, the upper column passes through the first column hole and is surrounded by the first column hole. The height of the upper column is equal to or greater than the height of the first column hole. The connecting piece passes through the fixing hole from the lower part of the middle plate and is threadedly connected to the fixing column at the lower part of the upper plate.

4. A stretch-retraction mechanism for a retractable tube according to claim 3, wherein The perimeter of the middle plate is surrounded by a barrier.

5. The stretching and contraction softening mechanism for a telescopic tube according to claim 1, characterized in that... The second post hole is a trapezoidal conical hole with a diameter that gradually decreases from top to bottom. The taper of the second post hole is the same as the taper of the lower post. The maximum diameter of the second post hole is less than or equal to the maximum diameter of the upper post.

6. The stretching and contraction softening mechanism for a telescopic tube according to claim 1, characterized in that... The lower plate body is provided with a buffer ring on its outer periphery, which is made of flexible material; the lower plate body is provided with a vent hole; the lower surface of the lower plate body is provided with a boss, which is located at the edge of the lower opening of the second column hole.

7. The stretching and contraction softening mechanism for a telescopic tube according to claim 6, characterized in that... The head of the connector is provided with a limiting piece. When the lower plate moves downward relative to the middle plate to the position furthest from the middle plate, the limiting piece abuts against the boss.

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