An airtightness testing device for hoses

Abstract

This invention discloses an airtightness testing device for rubber hoses, comprising two sets of first connectors mounted on a base. One set of first connectors is connected to the output end of an air pump, and the other set of first connectors is connected to a first pressure gauge. Each first connector includes a base pad fixedly connected to the base. An air guide tube for airtightness testing is disposed through the base pad, and a threaded ring is fixedly disposed on the base pad around the air guide tube. An external threaded sleeve is movably fitted around the threaded ring. A limiting sleeve for securing the end of the rubber hose is movably fitted between the inner side of the threaded ring and the outer side of the air guide tube. A limiting component for restricting the relative movement of the limiting sleeve and the threaded ring is jointly provided on the base pad and the air guide tube. In this invention, when the limiting sleeve restricts the end of the rubber hose, even if the rubber hose is subjected to tension, the friction between the rubber hose and the limiting sleeve will not pull the limiting sleeve away, thus minimizing the impact on the tightness of the fit between the rubber hose and the air guide tube. This method improves the accuracy of the test.

Description

Technical Field

[0001] This invention relates to the field of rubber hose quality testing technology, specifically to an airtightness testing device for rubber hoses. Background Technology

[0002] After production, the rubber hoses need to be tested for air tightness. Generally, workers immerse the hose body in a water tank, then breathe through one end of the hose, and observe whether bubbles are generated in the water tank to determine if the hose's air tightness is up to standard.

[0003] Chinese Patent Publication No. CN216207320U discloses an airtightness testing component for pipe fittings, comprising: an air path testing seat, a cap, an air inlet pipe, an air path sealing ring, and a pipe fitting sealing ring. The cap has an inner threaded hole, and the bottom wall of the threaded hole has a pipe fitting placement hole. The air path testing seat has a through-hole, which is stepped and includes, in sequence, a pipe fitting sealing section, a pipe fitting insertion section, and an air inlet threaded connection section. The air path testing seat has an annular sealing groove along the outer edge of the air inlet threaded connection section, and the air path sealing ring is disposed in the annular sealing groove. The air inlet pipe passes through the air path sealing ring and is threaded into the threaded connection section. The pipe fitting sealing ring is disposed in the pipe fitting sealing section. The air path testing seat has an installation threaded section at one end adjacent to the cap, which is disposed in the threaded hole of the cap.

[0004] In this method, when checking the air tightness of the hose, the end of the hose is always fitted onto the air nozzle and then tightened with a screw sleeve. The small opening at the end of the screw sleeve improves the stability of the hose connection. However, this method will put some pressure on the air-permeable part of the hose, which will introduce some error when using changes in air pressure index to determine air tightness. Summary of the Invention

[0005] The purpose of this invention is to provide an airtightness testing device for hoses, in order to solve the problem mentioned in the background art that improves the stability of hose connection by using a smaller opening at the end of the threaded sleeve, but this method will cause some compression to the air-permeable part of the hose, and there will be some error when using changes in air pressure index to determine airtightness.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An airtightness testing device for a rubber hose includes two sets of first connectors mounted on a base. One set of first connectors is connected to the output end of an air pump, and the other set of first connectors is connected to a first pressure gauge. Each first connector includes a base pad fixedly connected to the base. An air guide tube for airtightness testing is provided through the base pad. A threaded ring is fixedly provided on the base pad around the air guide tube. An external threaded sleeve is movably fitted around the threaded ring. A limiting sleeve for fixing the end of the rubber hose is movably assembled between the inner side of the threaded ring and the outer side of the air guide tube. A limiting component for limiting the relative movement of the limiting sleeve and the threaded ring is provided on both the base pad and the air guide tube.

[0008] As a further embodiment of the present invention: the limiting component includes a transmission cavity extending from the bottom pad to the threaded ring and an annular washer movably sleeved around the threaded ring. One end of the transmission cavity extends to the lower side of the annular washer, and a first sliding protrusion is slidably fitted at this end. The first sliding protrusion is fixedly connected to the lower end of the annular washer. The other end of the transmission cavity extends on the side wall opposite to the threaded ring and the limiting sleeve, and a second sliding protrusion is slidably fitted at this end. A second spring is connected between the annular washer and the bottom pad. The second spring causes the annular washer to move away from the bottom pad. When the annular washer approaches the bottom pad, the first sliding protrusion slides into the transmission cavity, while the second sliding protrusion extends out from the other end of the transmission cavity and forms a limiting fit with the limiting sleeve.

[0009] As a further aspect of the present invention: the limiting sleeve includes a ring body, the inner wall of the ring body and the threaded ring are slidably fitted together, multiple sets of limiting ridges are arranged in a ring array around the outer periphery of the ring body, a groove is embedded in the inner wall of the threaded ring to slide with the limiting ridge, a limiting hole is embedded in the limiting ridge, the limiting hole is adapted to the end of the second sliding protrusion, and an inner washer is fixedly fitted to the inner wall of the ring body.

[0010] As a further embodiment of the present invention: a winding wheel is installed on the base, a cavity is embedded in the lower end of the base, a cover plate is assembled and connected to the cavity, the winding wheel movably passes through the base and its end extends into the cavity, a first spring is connected between the winding wheel and the cover plate, and a limiting groove is embedded in the top of the cavity around the winding wheel, the limiting groove is in a limiting fit with the winding wheel.

[0011] As a further embodiment of the present invention: the winding wheel includes a shaft, the winding wheel passes through the base, and one end of the winding wheel extends into the cavity, while the other end is fixedly connected to a handle plate. A through hole is horizontally provided on the side of the winding wheel away from the cavity. A bushing is fixedly provided on the periphery of the end of the shaft that extends into the cavity. An assembly toothed ring is fitted on the side of the bushing near the limiting groove. The assembly toothed ring is sleeved and fixed on the periphery of the shaft. The assembly toothed ring and the limiting groove are correspondingly adapted. The first spring is sleeved on the periphery of the end of the shaft, and the end of the first spring away from the cover plate is rotatably connected to the bushing through a bearing.

[0012] As a further embodiment of the present invention: an airbag ring is inlaid at the edge of the through hole, a blind hole is embedded on the opposite side of the cover plate and the cavity, a piston plate that is slidably adapted to the blind hole is fixedly connected to the end of the shaft, and a first air guide hole is provided through the piston plate at the lower part of the shaft. One end of the first air guide hole is connected to the blind hole, and the other end of the first air guide hole is connected to the airbag ring.

[0013] As a further embodiment of the present invention: a threaded hole is embedded in the handle plate, and an inner threaded sleeve is movably connected to the threaded hole through a threaded engagement. A second air guide hole is connected to the lower part of the threaded hole. The second air guide hole is connected to the airbag ring. A third sliding protrusion is slidably engaged in the second air guide hole. The third sliding protrusion slides through the center of the inner threaded sleeve, and a third spring is connected between the end of the third sliding protrusion located in the second air guide hole and the inner threaded sleeve.

[0014] As a further aspect of the present invention: a set of second connectors is provided on one side of the shaft and on the base. The second connector on the base is connected to a second pressure gauge. The second connector on one side of the shaft is connected to the through hole. The structure of the second connector is exactly the same as that of the first connector.

[0015] Compared with the prior art, the beneficial effects of the present invention are: when the two ends of the hose to be tested are respectively connected to two sets of connectors, after the air pump is started, the airflow passes through one set of connectors and then through the hose, and finally through the other set of connectors, the air pressure can be detected by the first pressure gauge to know whether there is air leakage or cracks in the hose. When assembling the hose end, first, the outer threaded sleeve is placed around the hose end, then the limiting sleeve is placed around the hose, and then the hose is placed around the air guide tube. At the same time, the limiting sleeve and the threaded ring are engaged. Then, the outer threaded sleeve is tightened onto the threaded ring. As the outer threaded sleeve is tightened, it acts as a limiting component, thereby limiting the limiting sleeve. In this way, when the limiting sleeve limits the hose end, even if the hose is subjected to tension, the friction between the hose and the limiting sleeve will not pull the limiting sleeve off. This makes it less likely to affect the tightness of the fit between the hose and the air guide tube. This method can improve the accuracy of the test, especially when testing longer hoses. It also makes it less likely that the instability of the hose end connection caused by the coiling of the hose will lead to inaccurate testing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the connector structure in this invention.

[0018] Figure 3 for Figure 2 A magnified structural diagram of region A in the middle.

[0019] Figure 4 This is a schematic diagram of the limiting sleeve in this invention.

[0020] Figure 5 This is a schematic diagram of the base and limiting sleeve in Embodiment 1 of the present invention.

[0021] Figure 6 This is a schematic diagram of the limiting sleeve in this invention.

[0022] Figure 7 for Figure 6 A magnified structural diagram of region B in the middle.

[0023] Figure 8 This is a schematic diagram of the assembly of the toothed ring in this invention.

[0024] Figure 9 This is a schematic diagram of the base and limiting sleeve in Embodiment 2 of the present invention.

[0025] Figure 10 for Figure 9 A magnified structural diagram of region C in the middle.

[0026] In the diagram: 1-Base, 11-Cavity, 12-Limiting groove, 13-Cover plate, 14-Blind hole, 15-First spring, 2-Connector, 21-Bottom pad, 22-Air guide tube, 23-Threaded ring, 24-External threaded sleeve, 25-Annular washer, 26-Transmission cavity, 27-First sliding protrusion, 28-Second sliding protrusion, 29-Second spring, 3-Air pump, 4-First pressure gauge, 5-Winding reel, 51-Shaft. 52-Sleeve ring, 53-Piston plate, 54-Through hole, 55-Airbag ring, 56-First air guide hole, 57-Handle plate, 5701-Second air guide hole, 5702-Threaded hole, 5703-Inner threaded sleeve, 5704-Third sliding protrusion, 5705-Third spring, 58-Assembly toothed ring, 6-Second pressure gauge, 7-Limit sleeve, 71-Ring body, 72-Limit ridge, 73-Limit hole, 74-Inner washer. Detailed Implementation

[0027] Example 1:

[0028] In existing methods of checking the air tightness of rubber hoses, the hose end is typically fitted onto an air nozzle and then tightened with a threaded sleeve. The small opening at the end of the threaded sleeve improves the stability of the hose connection. However, this method can cause some compression to the air-permeable portion of the hose, leading to errors when determining air tightness based on changes in air pressure. To address this issue, please refer to [link to relevant documentation]. Figure 1-3 In this embodiment of the invention, an airtightness testing device for a rubber hose includes two sets of connectors 2 mounted on a base 1. One set of connectors 2 is connected to the output end of an air pump 3, and the other set of connectors 2 is connected to a first pressure gauge 4. Each connector 2 includes a base pad 21 fixedly connected to the base 1. An air guide tube 22 for airtightness testing is provided through the base pad 21. A threaded ring 23 is fixedly provided on the base pad 21 around the air guide tube 22. An external threaded sleeve 24 is movably fitted around the threaded ring 23. A limiting sleeve 7 for fixing the end of the rubber hose is movably assembled between the inner side of the threaded ring 23 and the outer side of the air guide tube 22. A limiting component for limiting the relative movement of the limiting sleeve 7 and the threaded ring 23 is provided on the base pad 21 and the air guide tube 22.

[0029] In this embodiment, the external threaded sleeve 24 is a conical structure with both ends through. The inner wall of the end with the larger diameter is threaded. This end of the external threaded sleeve 24 is engaged with the outer periphery of the threaded ring 23 through the threaded engagement. Preferably, the air pump 3 is a commonly used air pump in the prior art, or it can be an output device capable of outputting a constant airflow. When in use, the two ends of the hose to be tested are respectively connected to the two sets of connectors 2. After the air pump 3 is started, the airflow passes through one set of connectors 2 and then through the hose. Finally, after passing through the other set of connectors 2, the air pressure can be detected by the first pressure gauge 4 to know whether there is any leakage or crack in the hose. When assembling the hose end, first, the outer threaded sleeve 24 is placed around the hose end, then the limiting sleeve 7 is placed around the hose, and then the hose is placed around the air guide tube 22. At the same time, the limiting sleeve 7 and the threaded ring 23 are engaged. Then, the outer threaded sleeve 24 is tightened onto the threaded ring 23. As the outer threaded sleeve 24 is tightened, it acts as a limiting component, thereby limiting the limiting sleeve 7. In this way, when the limiting sleeve 7 limits the hose end, even if the hose is subjected to tension, the friction between the hose and the limiting sleeve 7 will not pull the limiting sleeve 7 away. This makes it less likely to affect the tightness of the fit between the hose and the air guide tube 22. This method can improve the accuracy of the test, especially when testing longer hoses. It also makes it less likely that the instability of the hose end connection caused by the coiling of the hose will lead to inaccurate testing.

[0030] Among them, such as Figure 1-10 As shown, the limiting assembly includes a transmission cavity 26 extending from the bottom pad 21 to the threaded ring 23 and an annular washer 25 movably sleeved around the threaded ring 23. One end of the transmission cavity 26 extends to the lower side of the annular washer 25, and a first sliding protrusion 27 is slidably fitted at this end. The first sliding protrusion 27 is fixedly connected to the lower end of the annular washer 25. The other end of the transmission cavity 26 extends on the side wall opposite to the limiting sleeve 7 of the threaded ring 23, and a second sliding protrusion 28 is slidably fitted at this end. A second spring 29 is connected between the annular washer 25 and the bottom pad 21. The second spring 29 causes the annular washer 25 to move away from the bottom pad 21. When the annular washer 25 approaches the bottom pad 21, the first sliding protrusion 27 slides into the transmission cavity 26, while the second sliding protrusion 28 extends out from the other end of the transmission cavity 26 and forms a limiting fit with the limiting sleeve 7.

[0031] In this embodiment, the transmission cavity 26 is provided with multiple sets of corresponding first sliding protrusions 27 arranged in a ring array below the annular gasket 25. The ends of the first sliding protrusions 27 and the second sliding protrusions 28 extending into the transmission cavity 26 are both provided with a sealing sliding fit. When the end of the outer threaded sleeve 24 does not press against the annular gasket 25, the end of the second sliding protrusion 28 does not extend out from the inside of the threaded ring 23. However, when the annular gasket 25 is pressed down and the second spring 29 is pressed downward, the first sliding protrusion 27 is pushed into the end of the transmission cavity 26. Through the air pressure transmission in the transmission cavity 26, the second sliding protrusion 28 can be pushed out of the transmission cavity 26, thereby forming a fit with the limiting sleeve 7 to restrict the limiting sleeve 7 from disengaging from the threaded ring 23. In this way, during use, simply tightening the outer threaded sleeve 24 can further ensure the end of the hose is locked.

[0032] Preferably, the base pad 21, the air guide tube 22, and the threaded ring 23 can be an integrated structure. The air guide tube 22 has a channel extending through the middle and penetrating the base pad 21. The portion of the air guide tube 22 extending out of the base pad 21 has annular protrusions around its periphery to prevent the tube from falling off. These protrusions can be an integrated structure on the air guide tube 22, or they can be rubber rings embedded around the air guide tube 22. The ends of the base pads 21 of the two sets of connectors 2 that are away from the air guide tube 22 are respectively connected to the output end of the air pump 3 and the first pressure gauge 4.

[0033] Further, such as Figure 2-4 As shown, the limiting sleeve 7 includes a ring body 71, which slides against the inner wall of the threaded ring 23. Multiple sets of limiting ribs 72 are arranged in a ring array around the outer periphery of the ring body 71. The inner wall of the threaded ring 23 is embedded with a groove that slides against the limiting ribs 72. Limiting holes 73 are embedded on the limiting ribs 72. The limiting holes 73 are adapted to the end of the second sliding protrusion 28. An inner washer 74 is fixedly fitted to the inner wall of the ring body 71.

[0034] In this embodiment, the inner washer 74 is preferably made of silicone or rubber, which can not only fit tightly to the end of the tube, but also adapt to the thickness of the tube, and has a good anti-slip effect. The limiting hole 73 can also be embedded in the periphery of the ring 71, depending on whether the end of the transmission cavity 26 is aligned with the groove on the inner wall of the threaded ring 23. The ring 71 is tightly fitted around the end of the hose by the inner washer 74 on the inner wall. At the same time, the cooperation of the limiting ridge 72 and the groove prevents the circumferential rotation of the ring 71, thereby limiting the circumferential rotation of the hose end. The limiting cooperation of the second sliding protrusion 28 and the limiting hole 73 allows the second sliding protrusion 28 to prevent the limiting hole 73 on the ring 71 from falling off the groove on the inner wall of the threaded ring 23 after the outer threaded sleeve 24 presses the annular washer 25. This further helps to prevent the hose end from falling off. Compared with the existing method of using the narrowing of the opening of the outer threaded sleeve 24 to clamp the hose, this method does not affect the air passage of the hose, which reduces the error when checking the air tightness of the hose and makes the air pressure test method more accurate.

[0035] Example 2:

[0036] When performing airtightness checks on hoses, sometimes the hoses are quite long. The conventional method is to coil the hose, but once air is introduced, the coiled state changes, making the placement of the hose at the testing site very inconvenient. Therefore, if... Figure 1-10 As shown, a winding wheel 5 is installed on the base 1, and a cavity 11 is embedded in the lower end of the base 1. A cover plate 13 is assembled and connected to the cavity 11, and a gap is provided between the cavity 11 and the cover plate 13. The winding wheel 5 movably passes through the base 1, and its end extends into the cavity 11. A first spring 15 is connected between the winding wheel 5 and the cover plate 13. A limiting groove 12 is embedded in the top of the cavity 11, located around the periphery of the winding wheel 5. The limiting groove 12 is in a movable limiting cooperation with the winding wheel 5.

[0037] In use, the first spring 15 lifts the winding wheel 5 upwards, and the engagement of the limiting groove 12 with the winding wheel 5 prevents the winding wheel 5 from falling off. The rubber tube can pass through the part of the winding wheel 5 that extends out of the base 1. After pressing the winding wheel 5, the limiting groove 12 and the winding wheel 5 are disengaged. At this time, rotating the winding wheel 5 can wind the rubber tube, making it easy to coil the rubber tube on the base 1. When the tube is wound to a state that is convenient for inspection, the pressing of the winding wheel 5 can be stopped. The first spring 15 will spring the winding wheel 5 up, and the engagement of the limiting groove 12 with the winding wheel 5 will prevent the winding wheel 5 from rotating back. It is convenient, flexible and stable to use.

[0038] like Figure 5-8As shown, the winding wheel 5 includes a shaft 51, which passes through the base 1 and has one end extending into the cavity 11. The other end is fixedly connected to a handle plate 57. A through hole 54 is horizontally provided on the side of the winding wheel 5 away from the cavity 11. A bushing 52 is fixedly provided on the periphery of the end of the shaft 51 that extends into the cavity 11. An assembly toothed ring 58 is fitted on the side of the bushing 52 near the limiting groove 12. The assembly toothed ring 58 is sleeved and fixed on the periphery of the shaft 51. The assembly toothed ring 58 and the limiting groove 12 are correspondingly adapted. The first spring 15 is sleeved on the periphery of the end of the shaft 51, and the end of the first spring 15 away from the cover plate 13 is rotatably connected to the bushing 52 through a bearing.

[0039] The axes of the shaft 51, bushing 52, mounting toothed ring 58, and first spring 15 are all aligned. Preferably, the mounting toothed ring 58 is toothed, and the limiting groove 12 is a toothed groove. During use, the engagement of the mounting toothed ring 58 and the limiting groove 12 restricts the rotation of the shaft 51 and prevents the shaft 51 from falling off. By pressing the shaft 51 with the handle plate 57, the mounting toothed ring 58 squeezes the first spring 15. Gradually, the mounting toothed ring 58 can be disengaged from the limiting groove 12, at which point the shaft 51 can be rotated. When the shaft 51 rotates, the first spring 15... A spring 15 rotates relative to a bearing embedded in the lower side of a bushing 52 without interference. A through hole 54 on the shaft 51 facilitates the passage of a rubber tube. During rotation, the rubber tube can be wound around the hole, making it flexible and convenient to use. After winding, when the handle plate 57 is released, the first spring 15 can push the shaft 51 away from the cavity 11 through the bushing 52 during the recovery process, thereby allowing the assembly toothed ring 58 to return to the engagement with the limiting groove 12. At this time, the wound rubber tube will not loosen due to the rotation of the shaft 51, making it more stable to use.

[0040] like Figure 5-7 As shown, an airbag ring 55 is inlaid at the edge of the through hole 54, and a blind hole 14 is embedded on the opposite side of the cover plate 13 and the cavity 11. A piston plate 53 that slides and adapts to the blind hole 14 is fixedly connected to the end of the shaft 51. A first air guide hole 56 is provided in the lower part of the shaft 51 through the piston plate 53. One end of the first air guide hole 56 is connected to the blind hole 14, and the other end of the first air guide hole 56 is connected to the airbag ring 55.

[0041] Preferably, the piston plate 53 and the side wall of the blind hole 14 are in a sealed fit, and the piston plate 53 is away from the bottom of the blind hole 14. When the shaft 51 is pressed, the piston plate 53 slides towards the bottom of the blind hole 14, and the air in the blind hole 14 enters the air bag ring 55 through the first air guide hole 56. Preferably, the air bag ring 55 is an annular rubber air bag, and it is provided at both ends of the through hole 54. In this way, after inflation, it can expand and fix the rubber tube. When the shaft 51 is rotated to wind the rubber tube, the rubber tube will not be damaged by the edge of the through hole 54, and the rubber tube can be prevented from slipping by the air bag ring 55 adhering to the rubber tube, making the winding process more stable. After the shaft 51 is released, the piston plate 53 moves away from the bottom of the blind hole 14, so the air bag ring 55 no longer expands, avoiding any impact during the test.

[0042] Furthermore, to facilitate adjustments based on the diameter of the hose, such as... Figure 9-10 As shown, a threaded hole 5702 is embedded in the handle plate 57. An inner threaded sleeve 5703 is movably connected to the threaded hole 5702 via a threaded engagement. A second air guide hole 5701 is connected to the lower part of the threaded hole 5702. The second air guide hole 5701 is connected to the airbag ring 55. A third sliding protrusion 5704 is slidably engaged in the second air guide hole 5701. The third sliding protrusion 5704 slides through the center of the inner threaded sleeve 5703. A third spring 5705 is connected between the end of the third sliding protrusion 5704 located in the second air guide hole 5701 and the inner threaded sleeve 5703.

[0043] The end of the third sliding protrusion 5704 that slides into the second air guide hole 5701 is in a sliding fit and is sealed. When in use, rotating the inner threaded sleeve 5703 can control the height at which the end of the third sliding protrusion 5704 slides in the second air guide hole 5701. At the same time, when the airbag ring 55 is inflated, the gas can push the third sliding protrusion 5704 to slide upward and compress the third spring 5705. Pressing the third sliding protrusion 5704 can control the degree of expansion of the airbag ring 55. Using the above structure, a pressure regulating effect of the airbag ring 55 can be formed. At the same time, by adjusting the inner threaded sleeve 5703, the degree of pressure control can be adjusted, and it is also convenient to adjust the restriction of the airbag ring 55 on the hose by hand.

[0044] Example 3:

[0045] To facilitate the detection of cracked locations, such as Figure 1 and 7As shown, a set of connectors 2 are provided on one side of the shaft 51 and on the base 1. The connector 2 on the base 1 is connected to a second pressure gauge 6, and the connector 2 on one side of the shaft 51 is connected to the through hole 54. This arrangement allows for the detection of internal pressure changes within the through hole 54 via a pipe connection. By continuously pulling the hose and pressing the shaft 51 or the third sliding protrusion 5704, the air bladder ring 55 is inflated, thereby sealing the inside of the through hole 54. The pressure changes inside the through hole 54 can be easily understood based on the display of the second pressure gauge 6, allowing for identification of the specific location of any leaks.

Claims

1. An airtightness testing device for hoses, comprising two sets of first connectors mounted on a base, one set of first connectors connected to the output end of an air pump, and the other set of first connectors connected to a first pressure gauge, characterized in that, The first connector includes a base pad fixedly connected to the base, an air guide tube for airtightness testing is provided through the base pad, and a threaded ring is fixedly provided on the base pad around the air guide tube. An external threaded sleeve is movably sleeved around the threaded ring. A limiting sleeve for sleeved and fixed end of the rubber tube is movably assembled between the inner side of the threaded ring and the outer side of the air guide tube. A limiting component for limiting the relative movement of the limiting sleeve and the threaded ring is provided on the base pad and the air guide tube. The limiting assembly includes a transmission cavity extending from the bottom pad to the threaded ring and an annular washer movably sleeved around the threaded ring. One end of the transmission cavity extends to the lower side of the annular washer, and a first sliding protrusion is slidably fitted at this end. The first sliding protrusion is fixedly connected to the lower end of the annular washer. The other end of the transmission cavity extends on the side wall opposite to the threaded ring and the limiting sleeve, and a second sliding protrusion is slidably fitted at this end. A second spring is connected between the annular washer and the bottom pad. The second spring causes the annular washer to move away from the bottom pad. When the annular washer approaches the bottom pad, the first sliding protrusion slides into the transmission cavity, while the second sliding protrusion extends out from the other end of the transmission cavity and forms a limiting fit with the limiting sleeve. The limiting sleeve includes a ring body, the inner wall of the ring body and the inner wall of the threaded ring are slidably fitted together, multiple sets of limiting ridges are arranged in a ring array around the outer periphery of the ring body, the inner wall of the threaded ring is embedded with a groove that slides with the limiting ridge, the limiting ridge is embedded with a limiting hole, the limiting hole is adapted to the end of the second sliding protrusion, and an inner washer is fixedly fitted to the inner wall of the ring body.

2. The airtightness testing device for hoses according to claim 1, characterized in that, A winding wheel is installed on the base, and a cavity is embedded in the lower end of the base. A cover plate is assembled and connected to the cavity. The winding wheel moves through the base and its end extends into the cavity. A first spring is connected between the winding wheel and the cover plate. A limit groove is embedded in the top of the cavity, located around the winding wheel. The limit groove is in a limiting fit with the winding wheel.

3. The airtightness testing device for hoses according to claim 2, characterized in that, The winding wheel includes a shaft, the winding wheel passes through the base, one end of which extends into the cavity, and the other end is fixedly connected to a handle plate. A through hole is horizontally provided on the side of the winding wheel away from the cavity.

4. The airtightness testing device for hoses according to claim 3, characterized in that, A bushing is fixedly provided on the outer periphery of one end of the shaft that extends into the cavity. An assembly toothed ring is fitted on the side of the bushing that is close to the limiting groove. The assembly toothed ring is sleeved and fixed on the outer periphery of the shaft. The assembly toothed ring and the limiting groove are correspondingly adapted. The first spring is sleeved on the outer periphery of the shaft end, and the end of the first spring away from the cover plate is rotatably connected to the bushing through a bearing.

5. The airtightness testing device for hoses according to claim 4, characterized in that, An airbag ring is embedded at the edge of the through hole. A blind hole is embedded on the opposite side of the cover plate and the cavity. A piston plate that slides and adapts to the blind hole is fixedly connected to the end of the shaft. A first air guide hole is provided through the piston plate at the lower part of the shaft. One end of the first air guide hole is connected to the blind hole, and the other end of the first air guide hole is connected to the airbag ring.

6. The airtightness testing device for hoses according to claim 5, characterized in that, The handle plate is embedded with a threaded hole, and an inner threaded sleeve is movably connected to the threaded hole through a threaded engagement. A second air guide hole is connected to the lower part of the threaded hole and is connected to the airbag ring. A third sliding protrusion is slidably engaged in the second air guide hole. The third sliding protrusion slides through the center of the inner threaded sleeve, and a third spring is connected between the end of the third sliding protrusion located in the second air guide hole and the inner threaded sleeve.

7. The airtightness testing device for hoses according to claim 6, characterized in that, A set of second connectors is provided on one side of the shaft and on the base. The second connector on the base is connected to a second pressure gauge. The second connector on one side of the shaft is connected to the through hole. The structure of the second connector is exactly the same as that of the first connector.

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