A novel peristaltic cleaning and disinfecting pipeline robot and method thereof

Abstract

The present invention provides a novel peristaltic cleaning and disinfecting pipeline robot and method thereof, comprising a pair of circumferential support moving mechanisms and a telescopic joint for connecting the pair of circumferential support moving mechanisms, the two ends of the telescopic joint are connected to the circumferential support moving mechanisms by universal joints, the circumferential support moving mechanism located at the front is also universally connected with a cleaning and disinfecting device, the cleaning and disinfecting device comprises a brush rod seat and a disinfectant container connected to the brush rod seat via a compression spring, a cleaning sponge is fixed to the outer surface of the disinfectant container, the circumferential support moving mechanism has a driving motor for driving the cleaning and disinfecting device to rotate, the present invention has a simple structure, and through two circumferential support moving mechanisms and the telescopic joint, the robot's movement posture in the pipeline is effectively maintained, and at the same time, it has a shock absorbing and damping effect, thereby ensuring the stability of the pipeline robot, and the use of the cleaning and disinfecting device can effectively reduce manual operations, and is suitable for cleaning and disinfection work in small and medium-sized pipelines.

Description

Technical Field

[0001] The invention relates to a novel peristaltic pipeline cleaning and disinfecting robot and a method thereof. Background Art

[0002] Many pipes in our daily life are difficult to clean due to their special structure. It is inevitable that a lot of dust and dirt will accumulate, which can easily breed bacteria and carry viruses. Therefore, pipes are the key disinfection targets in disinfection and sterilization activities. However, pipes are generally thin and long, which are not suitable for manual disinfection, which brings difficulties to the disinfection work. For this reason, a pipe cleaning and disinfection robot is designed to solve the cleaning and disinfection work in small and medium-sized pipes (pipe diameter 50mm~80mm).

[0003] According to the different driving modes of pipeline robots, they can be divided into the following types: wheeled robots, tracked robots, abdominal wall robots, walking robots, creeping robots, etc. In recent years, more and more scholars at home and abroad have focused on the research of small and medium-sized pipeline robots, and have also achieved certain results. However, the current research on them is still at a bottleneck stage, and there are still many key technical problems that have not been fundamentally solved. Existing pipeline robots are difficult to walk freely in complex small and medium-sized pipelines, especially difficult to pass through bends, and have poor stability; existing pipeline robots are insufficient in adapting to changes in pipe diameter, that is, they cannot walk in pipes with variable diameters; existing cleaning and disinfection pipeline robots are generally provided with disinfectant from the outside of the pipeline, resulting in low efficiency and complex structure of cleaning and disinfection, which affects the movement of pipeline robots in the pipeline.

[0004] There is currently a lack of peristaltic pipeline cleaning and disinfection robots on the market. The main technical problem is that current pipeline robots cannot pass through bends smoothly, have poor stability, are insufficiently able to adapt to changes in pipe diameter, and have low cleaning and disinfection efficiency. Summary of the invention

[0005] The present invention improves the above-mentioned problem, that is, the technical problem to be solved by the present invention is that the current pipeline robot cannot pass through bends smoothly, has poor stability, is insufficient in adapting to changes in pipe diameter, and has low efficiency in cleaning and disinfection work.

[0006] The specific implementation scheme of the present invention is: a new type of peristaltic cleaning and disinfecting pipeline robot, including a pair of circumferential support moving mechanisms and a telescopic joint for connecting the pair of circumferential support moving mechanisms, the two ends of the telescopic joint are connected to the circumferential support moving mechanisms through universal joints, the circumferential support moving mechanism located at the front is also universally connected to a cleaning and disinfecting device, the cleaning and disinfecting device includes a brush rod seat and a disinfectant container connected to the brush rod seat via a compression spring, a cleaning sponge is fixed to the outer surface of the disinfectant container, and the circumferential support moving mechanism has a drive motor for driving the cleaning and disinfecting device to rotate.

[0007] Furthermore, the telescopic joint includes a plurality of telescopic mechanisms connected by universal joints, the telescopic mechanisms include a telescopic motor, a screw rod coaxially connected to the output shaft of the telescopic motor, a nut sleeve is threadedly fitted on the side of the screw rod facing away from the telescopic motor, the telescopic motor is fixed with an end cover on the outer periphery, and the nut sleeve is fixed with a guide rod that passes through the end cover and is arranged parallel to the axial direction of the screw rod.

[0008] Furthermore, the circumferential support movement mechanism includes a casing, one end of which is provided with a retaining wheel along the circumferential direction that can continuously and tightly adhere to the pipe wall, and the retaining wheel is connected to the casing via a shock-absorbing spring.

[0009] Furthermore, the outer end of the casing is connected to a fixed plate via a connecting rod, a right-angle support is circumferentially fixed to the fixed plate, the shock-absorbing spring is fixed on the right-angle support, a retaining wheel seat is fixed to the outer end of the shock-absorbing spring, and the retaining wheel is axially hinged in the retaining wheel seat.

[0010] Furthermore, the driving motor is fixed on the casing, a screw is fixed at the output end of the driving motor, a pair of cross-arranged support rods extend from the casing, the lower ends of the support rods are hingedly connected to movable nuts that cooperate with the screw threads, the upper ends of the support rods are fixedly connected to pressure sensors, a pair of movable nuts are hinged at the lower ends of the support rods, and the movable nut at one end close to the driving motor is fixedly connected to the casing to prevent the movable nut from rotating, and the staggered parts of the pair of support rods are hingedly connected.

[0011] Furthermore, a sensor seat for fixing a pressure sensor is fixed to the upper end of the support rod.

[0012] Furthermore, a fixing seat of a limiting screw is fixed on a side of the casing away from the driving motor, and an outer periphery of the fixing seat is connected to the telescopic joint universal joint.

[0013] Furthermore, the cleaning sponge is arc-shaped, and the disinfectant container is provided with a one-way valve for flowing the cleaning liquid to the cleaning sponge. The disinfectant can periodically pass through the one-way valve through the rotation of the cleaning and disinfecting device, and thus be absorbed by the sponge.

[0014] Furthermore, a telescopic rod located inside the shock-absorbing spring is fixed on the right-angle support, and the telescopic rod is composed of a plurality of rods with gradually increasing diameters and mutually sleeved.

[0015] The present invention includes a peristaltic cleaning and disinfecting pipeline method, including using a novel peristaltic cleaning and disinfecting pipeline robot as described above, and the specific working steps are as follows:

[0016] In the initial state, first, the retaining wheel and the support rod of the rear circumferential support moving mechanism of the pipeline cleaning and disinfecting robot are made close to the pipe wall, while the support rod of the front circumferential support moving mechanism is not close to the pipe wall, the telescopic motor of the screw nut telescopic joint makes the nut sleeve move, so that the screw nut telescopic joint is extended, and then the retaining wheel and the support rod of the front circumferential support moving mechanism are made close to the pipe wall, and then the moving nut at the end of the rear circumferential support moving mechanism away from the driving motor moves under the drive of the driving motor to loosen the support rod from the pipe wall, the telescopic motor of the screw nut telescopic joint rotates forward to contract and pull the rear circumferential support moving mechanism, and then the driving motor is reversed, and the moving nut at the end away from the driving motor moves in the opposite direction under the drive of the driving motor, so that the support rod of the rear circumferential support moving mechanism is close to the pipe wall, completing a forward movement;

[0017] When the robot moves backward in the pipe, similar to the above forward movement, the support rod of the rear circumferential support moving mechanism is not close to the pipe wall, and the support rod of the front circumferential support moving mechanism is close to the pipe wall. The screw nut expansion joint is extended, and then the support rod of the front circumferential support moving mechanism is separated from the pipe wall. The support rod of the rear circumferential support moving mechanism is controlled to be close to the pipe wall, and the screw nut expansion joint is extended and contracted to pull the front circumferential support moving mechanism to move.

[0018] The pressure sensor is installed at the end of the support rod of the circumferential support moving mechanism. When the pressure change is detected, the telescopic motor is started to control the support rod to swing to close or loosen the pipe wall, so as to keep the wheel always close to the pipe wall.

[0019] When the pipe diameter changes, the retaining wheel expands and contracts under the action of the shock-absorbing spring to adapt to the change in pipe diameter.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In terms of passing through curves, this solution adopts an innovative design based on the centipede multi-segment structure with a telescopic section with a screw-nut structure. Multiple screw-nut sections are connected by a universal joint, which provides multiple degrees of freedom and enables the pipeline robot to complete turning movements in the pipeline.

[0022] In terms of poor stability, this solution adopts a creeping movement method, including a front and rear dual circumferential support movement mechanism, in which the retaining frame can always effectively maintain the robot's movement posture in the pipeline, and at the same time has a shock-absorbing and shock-reducing effect, ensuring the stability of the pipeline robot.

[0023] In terms of adapting to changes in pipe diameter, the circumferential support moving mechanism of this solution has retaining wheels set in the circumferential direction, which can be extended and retracted when the pipe diameter changes, thus achieving the ability to adapt to changes in pipe diameter. In terms of cleaning and disinfection efficiency, this solution has designed a device that can simultaneously achieve cleaning and disinfection work. The pipe wall is cleaned by a cleaning sponge, and the disinfectant in the disinfectant container flows out through a one-way valve to wet the cleaning sponge and apply it to the pipe wall to disinfect the pipe. At the same time, the cleaning and disinfection work is completed, which can effectively improve the efficiency of cleaning and disinfection. The entire working process of the pipeline robot is controlled by an electromechanical system, which can effectively reduce manual operations and is suitable for cleaning and disinfection work in small and medium-sized pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the front view of the new peristaltic pipe cleaning and disinfection robot;

[0025] Figure 2 It is a partial enlarged front view of the cleaning and disinfection device;

[0026] Figure 3 for Figure 2 A partial enlarged side cross-sectional view of AA in the middle;

[0027] Figure 4 It is a partially enlarged front view of the circumferential support moving mechanism;

[0028] Figure 5 It is a partial enlarged side view of the circumferential support moving mechanism;

[0029] Figure 6 This is a partial enlarged front view of the screw nut expansion joint;

[0030] Figure 7 This is a partial enlarged side view of the screw nut expansion joint.

[0031] In the figure: 1. cross universal joint; 2. nut sleeve; 3. brush rod seat; 4. cleaning sponge; 5. disinfectant container; 6. cleaning rod; 7. compression spring; 8. one-way valve; capacity sensor; 10. drive motor; 11. fixed disc; 12. pressure sensor; 13. sensor seat; 14. housing; 15. support rod; 16. connecting rod; 17. fixed seat; 18. screw; 19. support rod frame; 20. retaining wheel; 21. retaining wheel seat; 22. shock-absorbing spring; 23. retaining wheel telescopic rod; 24. right-angle support; 25. telescopic motor; 26. guide rod; 27. screw rod; 28. nut sleeve; 29. ​​end cover. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figures 1 to 7As shown, a new type of peristaltic cleaning and disinfecting pipeline robot mainly includes a cleaning and disinfecting device Ⅰ, a front circumferential support moving mechanism Ⅱ, a screw nut telescopic joint Ⅲ and a rear circumferential support moving mechanism Ⅳ, and each part is connected by a cross universal joint 1.

[0034] The telescopic joint is located between a pair of circumferential support moving mechanisms, and both ends of the telescopic joint are connected to the circumferential support moving mechanisms through universal joints. The cleaning and disinfection device is located on the front side of the front circumferential support moving mechanism and is universally connected to the front circumferential support moving mechanism.

[0035] The cleaning and disinfecting device includes a brush rod seat 3 and a disinfectant container 5 connected to the brush rod seat 3 via a compression spring. A cleaning sponge 4 is fixed to the outer surface of the disinfectant container 5. A one-way valve 8 is provided in the disinfectant container 5 for flowing cleaning liquid to the cleaning sponge 4. The disinfectant can periodically pass through the one-way valve through the rotation of the cleaning and disinfecting device, and thus be absorbed by the sponge.

[0036] In actual design, a capacity sensor is also provided in the disinfectant container. By detecting the capacity of the disinfectant in the disinfectant container 5, when the disinfectant is exhausted, the robot is controlled to exit the pipeline for refilling.

[0037] The cleaning and disinfecting device of the robot cleans the pipeline with a cleaning sponge 4, and controls the flow direction of the disinfectant through a one-way valve 8 located in the disinfectant container 5, so that the disinfectant flows out of the container, wets the cleaning sponge 4, and is applied to the pipe wall to disinfect the pipeline.

[0038] In order to locate the robot in the pipeline, in the present embodiment, the circumferential support moving mechanism comprises a casing 14, one end of which is provided with a retaining wheel 20 along the circumferential direction and capable of continuously adhering to the pipe wall, and the retaining wheel 20 is connected to the casing 14 via a shock-absorbing spring 22.

[0039] In this embodiment, the outer end of the casing is connected to a fixed plate via a connecting rod, and a right-angle support 24 is circumferentially fixed to the fixed plate. The shock-absorbing spring is fixed on the right-angle support 24, and a retaining wheel seat 21 is fixed to the outer end of the shock-absorbing spring. The retaining wheel is axially hinged in the retaining wheel seat, so that the retaining wheel 12 can rotate inside the retaining wheel 12.

[0040] In this embodiment, a drive motor 10 is mounted on a casing 14, and a screw is fixed at the output end of the drive motor 10. A pair of cross-arranged support rods 15 extend out of the casing. The lower ends of the support rods 15 are hingedly connected to movable nuts 19 that cooperate with the screw threads. The upper ends of the support rods are fixedly connected to pressure sensors 12. One end of the movable nut 19 close to the drive motor is fixedly connected to the casing to prevent the movable nut from rotating. The staggered parts of the pair of support rods are hingedly connected.

[0041] A pair of support rods 15 are in a scissor-like shape. When working, one of the two movable nuts 19 is in a fixed state, and the movable nut 19 at one end away from the driving motor is in a movable state. When the two movable nuts 19 are far away from each other, the upper ends of the pair of support rods are away from the pipe wall of the working pipe, and when the two movable nuts 19 are close to each other, the upper ends of the pair of support rods 15 are close to the pipe wall and can ensure that they are in close contact with the pipe wall of the working pipe, which can further stably fix the circumferential support moving mechanism tightly on the pipe wall.

[0042] A sensor seat 13 for fixing the pressure sensor 12 is fixed to the upper end of the support rod.

[0043] In order to realize the movement of the robot in the pipeline, the telescopic joint includes a plurality of telescopic mechanisms connected by universal joints, the telescopic mechanisms include a telescopic motor 25, a screw rod 27 coaxially connected to the output shaft of the telescopic motor 25, a nut sleeve 28 is threadedly matched on the side of the screw rod 27 away from the telescopic motor 25, the telescopic motor is fixed with an end cover 29 on the periphery, and a guide rod 26 is fixed on the nut sleeve that penetrates the end cover and is arranged parallel to the axial direction of the screw rod. The cooperation between the screw rod and the nut sleeve 28 can realize the extension and shortening of the telescopic joint as a whole, and multiple telescopic mechanisms connected by universal joints can meet the requirements of pipeline structures with different curvatures.

[0044] In the initial state, first, the retaining wheel and the support rod of the rear circumferential support moving mechanism of the pipeline cleaning and disinfecting robot are made close to the pipe wall, while the support rod of the front circumferential support moving mechanism is not close to the pipe wall, the telescopic motor 25 of the screw nut telescopic joint moves the nut sleeve 28 to extend the screw nut telescopic joint, and then the retaining wheel and the support rod of the front circumferential support moving mechanism are made close to the pipe wall, and then the moving nut of the rear circumferential support moving mechanism moves in the opposite direction to loosen the support rod from the pipe wall, and the telescopic motor 25 of the screw nut telescopic joint rotates forward to contract and pull the rear circumferential support moving mechanism, and then the support rod of the rear circumferential support moving mechanism is made close to the pipe wall, completing a forward movement;

[0045] When the robot retreats in the pipe, similar to the above forward movement, the support rod of the rear circumferential support moving mechanism is not close to the pipe wall, and the support rod of the front circumferential support moving mechanism is close to the pipe wall. The screw nut telescopic joint extends, and then the support rod of the front circumferential support moving mechanism is separated from the pipe wall. The support rod of the rear circumferential support moving mechanism is controlled to be close to the pipe wall, and the screw nut telescopic joint extends and contracts to pull the front circumferential support moving mechanism to move.

[0046] The pressure sensor is installed at the end of the support rod 15 of the circumferential support moving mechanism. When the pressure change is detected, the telescopic motor 25 is started to control the support rod 15 to swing to close or loosen the pipe wall. The wheel 20 (circumferential support moving mechanism) is always in contact with the pipe wall;

[0047] When the pipe diameter changes, the retaining wheel expands and contracts under the action of the shock-absorbing spring to adapt to the change in pipe diameter. In this embodiment, there are three retaining wheels arranged along the circumferential direction, which can also maintain the movement posture of the robot in the pipe, and will not cause one side of the robot to sag due to the weight of the circumferential support moving mechanism. The shock-absorbing spring 22 can provide a shock-absorbing effect, and the same shock-absorbing structure also exists in the cleaning and disinfection device.

[0048] A fixing seat 17 of a limiting screw is fixed on one side of the housing away from the driving motor, and the outer periphery of the fixing seat 17 is connected to the telescopic joint universal joint.

[0049] Embodiment 2. In this embodiment, a capacity sensor is installed in the disinfectant container 5 of the cleaning and disinfection device. By detecting the capacity of the disinfectant in the container, when the disinfectant is exhausted, the robot is controlled to exit the pipeline for replenishment. The cleaning sponge is arc-shaped, which can meet the needs of contraction in the case of a smaller pipe diameter, and a compression spring is used to ensure close contact between the cleaning sponge and the pipe wall.

[0050] The right-angle support 24 has a retractable telescopic rod 23 located in the shock-absorbing spring as a guide. The telescopic rod 23 is composed of a plurality of rods with gradually increasing diameters and are mutually nested. The telescopic rods are multi-sectioned and mutually nested to meet the telescopic structure of the retaining wheel. Similarly, a retractable cleaning rod 6 can also be designed between the disinfectant container 5 and the brush rod seat. The cleaning rod is also composed of at least two rods nested with each other, which can meet the telescopic movement of the disinfectant container 5 and the cleaning sponge.

[0051] The various components of the present invention are connected by universal joints to provide freedom, so as to enable the robot to move freely in the pipeline, including passing through bends and the like; the screw driven by the driving motor is connected to the cleaning rod brush rod seat through a universal joint, thereby driving the cleaning and disinfection device to rotate, causing the disinfectant in the disinfectant container to periodically pass through the one-way valve, and then periodically provide disinfectant solution to the cleaning sponge, which is applied to the inner wall of the cleaned pipeline, thereby completing the work of cleaning and disinfecting the pipeline.

[0052] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integrated molding using a casting process) (except when it is obviously impossible to use an integrated molding process).

[0053] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the present invention include states or shapes that are approximate, similar, or close to them.

[0054] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A new type of peristaltic cleaning and disinfection pipeline robot, characterized in that: It includes a pair of circumferential support moving mechanisms and a telescopic joint for connecting the pair of circumferential support moving mechanisms, the two ends of the telescopic joint are connected to the circumferential support moving mechanisms through universal joints, the circumferential support moving mechanism located at the front is also universally connected to a cleaning and disinfecting device, the cleaning and disinfecting device includes a brush rod seat and a disinfectant container connected to the brush rod seat via a compression spring, a cleaning sponge is fixed to the outer surface of the disinfectant container, and the circumferential support moving mechanism has a driving motor for driving the cleaning and disinfecting device to rotate; The telescopic joint comprises a plurality of telescopic mechanisms connected by universal joints, the telescopic mechanisms comprise a telescopic motor, a screw rod coaxially connected to the output shaft of the telescopic motor, a nut sleeve is threadedly matched on the side of the screw rod away from the telescopic motor, an end cap is fixed to the outer periphery of the telescopic motor, and a guide rod penetrating the end cap and arranged parallel to the axial direction of the screw rod is fixed to the nut sleeve; The circumferential support movement mechanism comprises a housing, one end of which is provided with a retaining wheel that can be in close contact with the pipe wall in a circumferential direction, and the retaining wheel is connected to the housing via a shock-absorbing spring; The outer end of the housing is connected to a fixed plate via a connecting rod, a right-angle support is circumferentially fixed to the fixed plate, the damping spring is fixed on the right-angle support, a retaining wheel seat is fixed to the outer end of the damping spring, and the retaining wheel is axially hinged in the retaining wheel seat; The driving motor is fixed on the casing, a screw is fixed at the output end of the driving motor, a pair of cross-arranged support rods extend out of the casing, the lower ends of the support rods are hingedly connected with moving nuts that match the screw threads, the upper ends of the support rods are fixedly connected with pressure sensors, a pair of moving nuts hinged at the lower ends of the support rods, the moving nut at one end close to the driving motor is fixedly connected to the casing to prevent the moving nut from rotating, and the staggered parts of the pair of support rods are hingedly connected; A sensor seat for fixing a pressure sensor is fixed at the upper end of the support rod; The cleaning sponge is arc-shaped, and a one-way valve for flowing cleaning liquid to the cleaning sponge is provided in the disinfectant container. The disinfectant can periodically pass through the one-way valve through the rotation of the cleaning and disinfecting device, and thus be absorbed by the sponge.

2. A novel peristaltic cleaning and disinfecting pipeline robot according to claim 1, characterized in that: A fixing seat of a limiting screw is fixed on one side of the casing away from the driving motor, and the outer periphery of the fixing seat is connected to the telescopic joint universal joint.

3. A novel peristaltic cleaning and disinfecting pipeline robot according to claim 2, characterized in that: A telescopic rod located inside the shock absorbing spring is fixed on the right-angle support, and the telescopic rod is composed of a plurality of rods with gradually increasing diameters and sleeved on each other.

4. A peristaltic cleaning and disinfection pipeline method, characterized in that: The invention comprises utilizing a novel peristaltic cleaning and disinfecting pipeline robot as described in claim 3, wherein the specific working steps are as follows: in an initial state, first, the retaining wheel and the support rod of the rear circumferential support moving mechanism of the pipeline cleaning and disinfecting robot are made close to the pipe wall, while the support rod of the front circumferential support moving mechanism is not close to the pipe wall, the telescopic motor of the screw nut telescopic joint makes the nut sleeve move, so that the screw nut telescopic joint is extended, and then the retaining wheel and the support rod of the front circumferential support moving mechanism are made close to the pipe wall, and then the moving nut at one end of the rear circumferential support moving mechanism away from the driving motor is driven by the driving motor to move so that the support rod is loosened from the pipe wall, and the telescopic motor of the screw nut telescopic joint rotates forward to contract and pull the rear circumferential support moving mechanism, and then the driving motor is reversed, and the moving nut at one end away from the driving motor is driven by the driving motor to move in the opposite direction, so that the support rod of the rear circumferential support moving mechanism is close to the pipe wall, completing a forward movement; When the robot moves backward in the pipe, similar to the above forward action, the support rod of the rear circumferential support moving mechanism is not close to the pipe wall, and the support rod of the front circumferential support moving mechanism is close to the pipe wall. The lead screw nut telescopic joint extends, and then the support rod of the front circumferential support moving mechanism is separated from the pipe wall, and the support rod of the rear circumferential support moving mechanism is controlled to be close to the pipe wall. The lead screw nut telescopic joint extends and contracts to pull the front circumferential support moving mechanism to move; a pressure sensor is installed at the end of the support rod of the circumferential support moving mechanism. When a pressure change is detected, the telescopic motor is started to control the support rod to swing to tighten or loosen the pipe wall, so that the keeping wheel is always in contact with the pipe wall; when the pipe diameter changes, the keeping wheel is extended and retracted under the action of the shock-absorbing spring to adapt to the change in pipe diameter.

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