Silicone rubber tensile stress relaxation experimental device and method for cable accessories

Abstract

The invention discloses a silicone rubber tensile stress relaxation experiment device and method for cable accessories, the device comprises an experiment box, a translation mechanism, a first simulation mechanism, a second simulation mechanism and a tension mechanism, the experiment box comprises an outer box and a moving box; the translation mechanism is used for driving the moving box to move to a first position or a second position in the moving channel; the first simulation mechanism comprises a first temperature and humidity adjusting part and an ultraviolet emitter; the second simulation mechanism comprises a second temperature and humidity adjusting part and an acid mist spraying part; and the tension mechanism is mounted in the moving box and is used for clamping and tensioning a plurality of silicon rubber samples. According to the invention, two environmental conditions of high temperature and rain which have obvious influence on silicone rubber aging can be respectively simulated, alternate switching of the environmental conditions can be realized, and a complex environmental change mode faced by a silicone rubber product in an actual use process is highly restored, so that an experimental result is more suitable for an actual use condition, and the experimental efficiency is improved. And the tensile stress relaxation characteristic of the silicone rubber in a multi-physics coupling environment can be disclosed.

Description

Technical Field

[0001] This application relates to the technical field of rubber tensile stress relaxation experiments, and particularly to a silicone rubber tensile stress relaxation experimental device and method for cable accessories. Background Art

[0002] The rubber tensile stress relaxation experiment is crucial in the field of rubber material property research. It can effectively reveal the characteristic that the internal stress of rubber material gradually decays with time when subjected to a constant tensile strain, and plays an irreplaceable role in deeply understanding the mechanical properties and service life of rubber materials.

[0003] Due to its high elasticity, good mechanical properties, excellent electrical properties and other advantages, silicone rubber materials have been widely used in cross-linked polyethylene cable accessories. In addition, it is also widely used in various different environments. For example, in high-voltage transmission lines, silicone rubber insulators are used to ensure the safe and stable power transmission; in the sealing of building curtain walls, silicone rubber sealants play a key role in waterproofing, dustproofing and sound insulation; the door and window sealing strips of automobiles are made of silicone rubber material to ensure the sealing and comfort inside the vehicle.

[0004] However, silicone rubber products face complex and harsh environmental challenges during actual use. Among them, conditions such as high temperature, exposure to sunlight and rain have the most significant impact on the aging of silicone rubber products. In a high-temperature environment, the molecular structure of silicone rubber will be damaged, causing the molecular chain to break, and thus accelerating its aging process. Under rain conditions, the air humidity increases significantly, and at the same time, rainwater usually has a certain acidity, which will react with silicone rubber and further exacerbate the aging phenomenon of the rubber. More critically, high-temperature exposure and rain conditions do not exist in isolation, but will alternate repeatedly. This complex environmental change pattern will further accelerate the aging of silicone rubber products, seriously affecting their performance and service life.

[0005] At present, the existing rubber tensile stress relaxation experiments are usually designed to only consider a fixed combination of specific environmental parameters, focusing on studying the stress relaxation characteristics of rubber in a single and stable environment. However, this experimental method ignores the impact of the switching process of different environmental conditions on rubber aging. Due to the frequent changes of conditions in the actual environment, the existing experimental methods cannot accurately simulate the aging process of silicone rubber products in the actual environment, resulting in a large deviation between the experimental results and the actual use situation, and it is difficult to meet the requirements for the performance evaluation of silicone rubber products in a multi-physical field coupling environment. Therefore, it is of urgent practical significance to develop an experimental device and method that can comprehensively consider the switching of different environmental conditions and their influence on the tensile stress relaxation of silicone rubber. Summary of the Invention

[0006] To solve the technical problems in the prior art, the present application provides a silicone rubber tensile stress relaxation experimental device and method for cable accessories.

[0007] The silicone rubber tensile stress relaxation experimental device and method for cable accessories provided by the present application adopt the following technical solutions: A silicone rubber tensile stress relaxation experimental device for cable accessories, comprising: An experimental chamber, the experimental chamber includes an outer box and a movable box, there is a movable channel inside the outer box, the movable box is slidably arranged in the movable channel, and the upper end of the movable box is open; A translation mechanism, the translation mechanism is connected to the movable box and is used to drive the movable box to move to a first position or a second position in the movable channel; A first simulation mechanism, the first simulation mechanism includes a first temperature and humidity adjustment member and an ultraviolet emitter. When the movable box reaches the first position, the first temperature and humidity adjustment member can adjust the temperature and humidity of the movable box, and the ultraviolet emitter is used to emit ultraviolet rays into the movable box; A second simulation mechanism, the second simulation mechanism includes a second temperature and humidity adjustment member and an acid mist spraying member. When the movable box reaches the second position, the second temperature and humidity adjustment member can adjust the temperature and humidity of the movable box, and the acid mist spraying member is used to spray acid mist into the movable box; and, A tensioning mechanism, the tensioning mechanism is installed in the movable box and is used to clamp and tension a plurality of silicone rubber samples.

[0008] By adopting the above technical solutions, it is possible to respectively simulate environmental conditions such as high temperature and rain that have a significant impact on the aging of silicone rubber, and to achieve alternate switching under multi-physical field coupling environmental conditions, highly restoring the complex environmental change patterns faced by silicone rubber products in a multi-physical field coupling environment, making the experimental results more in line with the actual use situation; by the tensioning mechanism to stretch the silicone rubber samples in different simulation environments and during the environmental switching process, and to monitor the stress relaxation data in real time, it is possible to comprehensively and deeply reveal the tensile stress relaxation characteristics of silicone rubber under a multi-physical field coupling environment, providing strong data support for accurately evaluating the mechanical properties and service life of silicone rubber materials.

[0009] Preferably, the translation mechanism includes a first pulling component and a second pulling component. The first pulling component includes a first pulling motor, a first winding drum, a first pulling rope, and a plurality of first guiding wheels. The fixed end of the first pulling motor is fixed inside the outer box. The first winding drum is coaxially fixed to the output end of the first pulling motor. The first pulling rope is wound around the first winding drum. The free end of the first pulling rope is connected to one end of the moving box. Each of the first guiding wheels is rotatably arranged inside the outer box and is used for the first pulling rope to be wound around, so as to guide the extending direction of the first pulling rope. The second pulling component includes a second pulling motor, a second winding drum, a second pulling rope, and a plurality of second guiding wheels. The fixed end of the second pulling motor is fixed inside the outer box. The second winding drum is coaxially fixed to the output end of the second pulling motor. The second pulling rope is wound around the second winding drum. The free end of the second pulling rope is connected to one end of the moving box. Each of the second guiding wheels is rotatably arranged inside the outer box and is used for the second pulling rope to be wound around, so as to guide the extending direction of the second pulling rope.

[0010] By adopting the above technical solution, by setting two pulling components, the flexible movement of the moving box in two directions is realized, and the requirements of different experimental scenarios can be met.

[0011] Preferably, a first installation groove is formed above the outer box relative to the first position, and the first temperature and humidity adjusting member and the ultraviolet emitter are both installed in the first installation groove; a second installation groove is formed above the outer box relative to the second position, and the second temperature and humidity adjusting member and the acid mist spraying member are both installed in the second installation groove; the lower end of the moving box is open, a first collection groove is formed below the outer box relative to the first position, and a second collection groove is formed below the outer box relative to the second position.

[0012] By adopting the above technical solution, a first collection groove and a second collection groove are respectively arranged below the outer box relative to the first position and the second position, and the debris that may fall from the silicone rubber sample during the aging process can be effectively collected. Especially the second collection groove can not only collect the debris, but also collect the liquid condensed from the acid mist sprayed by the acid mist spraying member. This design avoids the debris and liquid from scattering inside the equipment, prevents pollution and damage to the equipment, and ensures the normal operation of the equipment.

[0013] Preferably, the acid mist spraying member includes an atomizing nozzle, an acid liquid tank, and a pump body. The atomizing nozzle is installed in the second installation groove, the outlet of the atomizing nozzle faces the clamping position of the tensioning mechanism, the acid liquid tank is used for storing acid liquid, the inlet of the pump body is communicated with the acid liquid tank, and the outlet of the pump body is communicated with the inlet of the atomizing nozzle.

[0014] By adopting the above technical solution, the acid mist can act on the silicone rubber sample at the clamping position of the tension mechanism accurately, so as to precisely simulate the acid mist erosion environment that the silicone rubber sample may face in actual use, provide reliable experimental conditions for testing the performance of the silicone rubber sample in the acid mist environment, make the test results closer to the actual situation, and improve the accuracy and effectiveness of the test.

[0015] Preferably, there is also a third position in the moving channel. An operation opening is provided above the outer box relative to the third position, and a cover plate that can be opened or closed is arranged at the operation opening.

[0016] By adopting the above technical solution, the cover plate can be opened to perform the installation and disassembly tasks of the silicone rubber sample.

[0017] Preferably, an air inlet hole is provided on the cover plate; the experimental device for tensile stress relaxation of silicone rubber for cable accessories further includes an air extraction mechanism. The air extraction mechanism includes an air suction pump and a suction pipe. The inlet of the air suction pump is communicated with one end of the suction pipe, and the other end of the suction pipe is communicated with the third position in the moving channel.

[0018] By adopting the above technical solution, the interference of the acid mist-containing gas generated by the rain simulation experiment on the high-temperature simulation experiment is effectively avoided. The presence of acid mist may change the gas composition, humidity and other conditions of the high-temperature environment, and thus affect the aging test results of the silicone rubber sample under the exposure condition. Through air extraction and gas replacement, it is ensured that the high-temperature simulation experiment is carried out in a relatively pure environment, so that the test results can more accurately reflect the aging performance of the silicone rubber sample in the high-temperature environment, and the accuracy and reliability of the experimental data are improved.

[0019] Preferably, the tension mechanism includes a fixed rod, a bottom plate, two end plates, a double-headed screw rod, a handle, two moving plates and guide rods. The fixed rod is fixed in the moving box, the bottom plate is fixed on the fixed rod, the two end plates are respectively fixed at both ends of the bottom plate, the two ends of the double-headed screw rod are respectively rotatably arranged on the two end plates, a handle is fixed at one end of the double-headed screw rod, first screw holes are respectively provided on the two moving plates, and the two ends of the double-headed screw rod are respectively in threaded connection with the first screw holes on the two end plates. First clamping members are installed on the end plates, and the first clamping members are used for clamping one end of the silicone rubber sample. Tensile force measuring members are installed on the moving plates, and the measuring ends of the tensile force measuring members are connected with a second clamping member, and the second clamping member is used for clamping the other end of the silicone rubber sample. The two ends of the guide rod are respectively fixed on the two end plates, and guide holes for the guide rod to pass through are respectively provided on the two moving plates.

[0020] By adopting the above technical solution, through the threaded connection between the double-headed lead screw and the threaded hole on the moving plate, the precise adjustment of the position of the moving plate can be achieved, and then the stretching degree of the silicone rubber sample can be precisely controlled. The screw drive has high precision and stability, and the silicone rubber sample can be stretched to a specific length or stretching rate according to the experimental requirements, meeting the precise requirements for the stretching degree in different experiments. Moreover, the experiments on multiple silicone rubber samples can be carried out at one time, improving the experimental efficiency.

[0021] Preferably, the first clamping member includes a first clamping frame, a first clamping block and a first locking screw. The first clamping frame is fixed to the end plate. A second threaded hole is provided on the first clamping frame. The first clamping block is slidably disposed in the first clamping frame. The first locking screw is threadedly connected to the second threaded hole, and the first locking screw is rotatably connected to the first clamping block.

[0022] By adopting the above technical solution, a large clamping force can be generated to ensure that the silicone rubber sample does not loosen or slip during the tensile experiment, guaranteeing the smooth progress of the experiment and the accuracy of the data.

[0023] Preferably, the second clamping member includes a second clamping frame, a second clamping block and a second locking screw. The second clamping frame is fixed to the measuring end of the tensile measuring member. A third threaded hole is provided on the second clamping frame. The second clamping block is slidably disposed in the second clamping frame. The second locking screw is threadedly connected to the third threaded hole, and the second locking screw is rotatably connected to the second clamping block.

[0024] By adopting the above technical solution, the second clamping frame is fixed to the measuring end of the tensile measuring member, providing a stable installation position for the entire second clamping member. This enables the second clamping member to move stably with the tensile measuring member during the tensile experiment, ensuring that when the silicone rubber sample is stretched, the force condition thereof can be accurately transmitted to the tensile measuring member.

[0025] The present invention also provides a method for the tensile stress relaxation experiment of silicone rubber for cable accessories, which is applicable to the tensile stress relaxation experiment device for silicone rubber for cable accessories and includes the following steps: Step 1: Experiment preparation: Fix a plurality of silicone rubber samples on the tensile mechanism in the moving box. The tensile mechanism stretches the silicone rubber samples according to a predetermined stretching rate and can continuously monitor the tensile force of the silicone rubber samples. Step 2: High-temperature simulation stage: Through the translation mechanism, drive the mobile box to move to the first position in the mobile channel. The first temperature and humidity adjustment component is activated. According to the preset experimental requirements, accurately adjust the temperature and humidity inside the mobile box to simulate a high-temperature environment. At the same time, the ultraviolet emitter is turned on to emit ultraviolet rays into the mobile box to simulate strong ultraviolet radiation. The tension mechanism continuously monitors and records the tensile force change data of the silicone rubber sample in the high-temperature simulation environment; Step 3: Rain simulation stage: After the preset time, the translation mechanism operates again to move the mobile box to the second position in the mobile channel. The second temperature and humidity adjustment component starts to work to adjust the temperature and humidity inside the mobile box to create a high-humidity environment similar to that in a rain environment. The acid mist spraying component is activated to spray acid mist into the mobile box to simulate the acidity of rainwater. The tension mechanism continuously monitors and records the tensile force change data of the silicone rubber sample in the high-temperature and rain simulation environment; Step 4: Cyclic switching and data acquisition: According to the experimental requirements, the translation mechanism can repeatedly switch the state of the mobile box between the first position and the second position to simulate the alternating recurrence of high-temperature and rain conditions. The tension mechanism continuously monitors and records the tensile force change data of the silicone rubber sample; Step 5: End of experiment: After completing all the preset experimental cycle times or reaching the experimental time, the translation mechanism moves the mobile box back to the initial position, stops the operation of the tension mechanism, the first simulation mechanism, and the second simulation mechanism, takes out the silicone rubber sample, and ends the experiment. The degree of influence of high temperature, rain, and the switching process between the two environments on the aging process of the silicone rubber can be obtained from the tensile force change data of the silicone rubber sample recorded by the tension mechanism.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: 1. This experimental device can separately simulate the two environmental conditions of high temperature and rain that have a significant impact on the aging of silicone rubber, and can achieve the alternating switching of the two environmental conditions, highly restoring the complex environmental change mode faced by silicone rubber products during actual use, making the experimental results more in line with the actual use situation; by stretching the silicone rubber sample through the tension mechanism in different simulation environments and during the environmental switching process and real-time monitoring the stress relaxation data, it can comprehensively and deeply reveal the tensile stress relaxation characteristics of silicone rubber in a multi-physical field coupling environment, providing strong data support for accurately evaluating the mechanical properties and service life of silicone rubber materials; 2. The inlet of the suction pump is connected to one end of the suction pipe, and the other end of the suction pipe is connected to the third position in the moving channel. When the suction pump works to generate suction, the gas containing acid mist in the moving box is extracted to the outside of the equipment through the suction pipe. While exhausting the gas, fresh air from the outside enters the moving box through the air inlet holes on the cover plate. As the gas extraction progresses, the gas containing acid mist in the moving box is gradually extracted, and fresh air is continuously replenished, realizing the replacement of the gas in the moving box. Through the above settings, the interference of the gas containing acid mist generated by the rain simulation experiment on the high-temperature simulation experiment is effectively avoided. The presence of acid mist may change the gas composition, humidity and other conditions in the high-temperature environment, and thus affect the aging test results of the silicone rubber sample under high-temperature conditions. Through gas extraction and replacement, it is ensured that the high-temperature simulation experiment is carried out in a relatively pure environment, making the test results more accurately reflect the aging performance of the silicone rubber sample under high-temperature conditions, and improving the accuracy and reliability of the experimental data. Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of the silicone rubber tensile stress relaxation experimental device for cable accessories provided by an embodiment of the present application when the moving box moves to the first position; Figure 2 is Figure 1 a schematic structural diagram of the left part of the silicone rubber tensile stress relaxation experimental device for cable accessories in Figure 3 is Figure 2 a schematic structural diagram of the tension mechanism in Figure 4 is Figure 3 a partial enlarged view of area A in Figure 5 is Figure 3 a partial enlarged view of area B in Figure 6 is Figure 3 a top view of the tension mechanism in Figure 7 is Figure 1 a schematic structural diagram of the silicone rubber tensile stress relaxation experimental device for cable accessories when the moving box moves to the second position; Figure 8 is Figure 7 a schematic structural diagram of the right part of the silicone rubber tensile stress relaxation experimental device for cable accessories in Description of reference numerals: 1. experimental chamber; 11. outer box; 111. moving channel; 112. first installation groove; 113. second installation groove; 114. first collection groove; 115. second collection groove; 116. cover plate; 1161. air inlet hole; 12. moving box; 2. translation mechanism; 21. first pulling assembly; 211. first pulling motor; 212. first winding drum; 213. first pulling rope; 214. first guide wheel; 22. second pulling assembly; 221. second pulling motor; 222. second winding drum; 223. second pulling rope; 224. second guide wheel; 3. first simulation mechanism; 31. first temperature and humidity regulating member; 32. ultraviolet emitter; 4. second simulation mechanism; 41. second temperature and humidity regulating member; 42. acid mist spraying member; 421. atomizing nozzle; 422. acid liquid tank; 423. pump body; 5. tensioning mechanism; 51. fixed rod; 52. bottom plate; 53. end plate; 531. guide rod; 54. double-headed screw rod; 55. handle; 56. moving plate; 57. first clamping member; 571. first clamping frame; 572. first clamping block; 573. first locking screw; 58. tensile force measuring member; 59. second clamping member; 591. second clamping frame; 592. second clamping block; 593. second locking screw; 6. silicone rubber sample; 7. air extraction mechanism; 71. suction pump; 72. suction pipe. Detailed implementation manners

[0028] The following further elaborates on this application Figures 1-8 in conjunction with the attached drawings.

[0029] The embodiment of this application discloses a silicone rubber tensile stress relaxation experiment device for cable accessories. Referring to Figure 1 , the silicone rubber tensile stress relaxation experiment device for cable accessories includes an experimental chamber 1, a translation mechanism 2, a first simulation mechanism 3, a second simulation mechanism 4, and a tensioning mechanism 5.

[0030] The experimental chamber 1 includes an outer box 11 and a moving box 12. There is a moving channel 111 inside the outer box 11. The moving box 12 is slidably arranged in the moving channel 111, and the upper end of the moving box 12 is open.

[0031] The translation mechanism 2 is connected to the moving box 12 and is used to drive the moving box 12 to move to the first position or the second position in the moving channel 111.

[0032] The first simulation mechanism 3 is used to simulate the rubber aging process under high temperature conditions. The first simulation mechanism 3 includes a first temperature and humidity regulating member 31 and an ultraviolet emitter 32. When the moving box 12 reaches the first position, the first temperature and humidity regulating member 31 can adjust the temperature and humidity of the moving box 12, and the ultraviolet emitter 32 is used to emit ultraviolet rays into the moving box 12.

[0033] The second simulation mechanism 4 is used to simulate the rubber aging process under rain conditions. The second simulation mechanism 4 includes a second temperature and humidity adjustment member 41 and an acid mist spraying member 42. When the moving box 12 reaches the second position, the second temperature and humidity adjustment member 41 can adjust the temperature and humidity of the moving box 12, and the acid mist spraying member 42 is used to spray acid mist into the moving box 12.

[0034] The tensioning mechanism 5 is installed in the moving box 12 and is used to clamp and tension a plurality of silicone rubber samples 6.

[0035] The simulation process of the above-mentioned silicone rubber tensile stress relaxation experimental device for cable accessories is as follows: Step 1: Experiment preparation: Fix a plurality of silicone rubber samples 6 on the tensioning mechanism 5 in the moving box 12. The tensioning mechanism 5 stretches the silicone rubber samples 6 at a predetermined stretching rate and can continuously monitor the magnitude of the tensile force of the silicone rubber samples 6. Step 2: High-temperature simulation stage: Through the translation mechanism 2, drive the moving box 12 to move to the first position in the moving channel 111. The first temperature and humidity adjustment member 31 is started, and according to the experimental preset requirements, accurately adjust the temperature and humidity in the moving box 12 to simulate a high-temperature environment. At the same time, the ultraviolet emitter 32 is turned on to emit ultraviolet rays into the moving box 12 to simulate strong ultraviolet radiation. The tensioning mechanism 5 continuously monitors and records the change data of the tensile force of the silicone rubber samples 6 in the high-temperature simulation environment. Step 3: Rain simulation stage: After a preset time, the translation mechanism 2 operates again to move the moving box 12 to the second position in the moving channel 111. The second temperature and humidity adjustment member 41 starts to work to adjust the temperature and humidity in the moving box 12 to create a high-humidity environment similar to that under rain conditions. The acid mist spraying member 42 is started to spray acid mist into the moving box 12 to simulate the acidity of rainwater. The tensioning mechanism 5 continuously monitors and records the change data of the tensile force of the silicone rubber samples 6 in the high-temperature and rain simulation environment. Step 4: Cycle switching and data acquisition. According to the experimental requirements, the state of the moving box 12 between the first position and the second position can be repeatedly switched through the translation mechanism 2 to simulate the alternating recurrence of high-temperature and rain conditions. The tensioning mechanism 5 continuously monitors and records the change data of the tensile force of the silicone rubber samples 6. Step 5: Experiment end: After completing all preset experimental cycle times or reaching the experimental time, the translation mechanism 2 moves the moving box 12 back to the initial position, stops the operation of the tensioning mechanism 5, the first simulation mechanism 3, and the second simulation mechanism 4, takes out the silicone rubber samples 6, and ends the experiment. The degree of influence of high temperature, rain, and the switching process between the two environments on the silicone rubber aging process is obtained from the change data of the tensile force of the silicone rubber samples 6 recorded by the tensioning mechanism 5.

[0036] The technical effects of the above solution include: (1)Precisely simulate the multi-physical field coupling environment: This experimental device can separately simulate two environmental conditions that significantly affect the aging of silicone rubber, namely high temperature and rain, and can achieve the alternating switching of the two environmental conditions, highly restoring the complex environmental change patterns faced by silicone rubber products during use in a multi-physical field coupling environment, making the experimental results more in line with the actual use situation; (2)Fully reveal the stress relaxation characteristics: By stretching the silicone rubber sample 6 through the tension mechanism 5 in different simulated environments and during the environmental switching process, and real-time monitoring the stress relaxation data, it is possible to fully and deeply reveal the tensile stress relaxation characteristics of silicone rubber in a multi-physical field coupling environment, providing strong data support for accurately evaluating the mechanical properties and service life of silicone rubber materials.

[0037] In one embodiment, please refer to Figure 2 and Figure 8 , the translation mechanism 2 includes a first pulling component 21 and a second pulling component 22. The first pulling component 21 includes a first pulling motor 211, a first reel 212, a first pulling rope 213, and a plurality of first guide wheels 214. The fixed end of the first pulling motor 211 is fixed inside the outer box 11. The first reel 212 is coaxially fixed to the output end of the first pulling motor 211. The first pulling rope 213 is wound around the first reel 212. The free end of the first pulling rope 213 is connected to one end of the moving box 12. Each of the first guide wheels 214 is rotatably provided in the outer box 11 and is used for winding the first pulling rope 213 to guide the extending direction of the first pulling rope 213. The second pulling component 22 includes a second pulling motor 221, a second reel 222, a second pulling rope 223, and a plurality of second guide wheels 224. The fixed end of the second pulling motor 221 is fixed inside the outer box 11. The second reel 222 is coaxially fixed to the output end of the second pulling motor 221. The second pulling rope 223 is wound around the second reel 222. The free end of the second pulling rope 223 is connected to one end of the moving box 12. Each of the second guide wheels 224 is rotatably provided in the outer box 11 and is used for winding the second pulling rope 223 to guide the extending direction of the second pulling rope 223. When it is necessary to move to the left, the first reel 212 winds up and the second reel 222 unwinds. When it is necessary to move to the right, the first reel 212 unwinds and the second reel 222 winds up.

[0038] In this embodiment, when it is necessary to move the moving box 12 to the left, the first pulling motor 211 is started to drive the first reel 212 to wind up the first pulling rope 213, thereby pulling the moving box 12 to move to the left. At the same time, the second pulling motor 221 is started to make the second reel 222 pay out the second pulling rope 223. When it is necessary to move the moving box 12 to the right, the second pulling motor 221 is started to drive the second reel 222 to wind up the second pulling rope 223, pulling the moving box 12 to move to the right. At the same time, the first pulling motor 211 is started to make the first reel 212 pay out the first pulling rope 213. By providing two pulling assemblies, the flexible movement of the moving box 12 in two directions is realized, and the requirements of different experimental scenarios can be met.

[0039] In one of the embodiments, please refer to Figures 2-8 , a first installation groove 112 is formed above the outer box 11 relative to the first position, and the first temperature and humidity adjusting member 31 and the ultraviolet emitter 32 are both installed in the first installation groove 112; a second installation groove 113 is formed above the outer box 11 relative to the second position, and the second temperature and humidity adjusting member 41 and the acid mist spraying member 42 are both installed in the second installation groove 113; the lower end of the moving box 12 is provided with an opening, and a first collection groove 114 is formed below the outer box 11 relative to the first position. The first collection groove 114 is used to collect the debris that may fall from the silicone rubber sample during the aging process. A second collection groove 115 is formed below the outer box 11 relative to the second position. The second collection groove 115 is used to collect the debris that may fall from the silicone rubber sample during the aging process and the liquid condensed from the acid mist sprayed by the acid mist spraying member 42, and needs to be cleaned regularly.

[0040] In this embodiment, the first temperature and humidity adjusting member 31 and the ultraviolet emitter 32 are installed in the first installation groove 112, and an environment with specific temperature, humidity and ultraviolet irradiation can be simulated for relevant aging tests on the silicone rubber sample; the second temperature and humidity adjusting member 41 and the acid mist spraying member 42 are installed in the second installation groove 113, and an environment with temperature and humidity changes and acid mist erosion can be simulated. By providing different simulated environments, various different types of aging tests can be carried out on the silicone rubber sample, meeting diversified test requirements, improving the comprehensiveness and accuracy of test results, and providing richer data support for evaluating the performance of the silicone rubber sample.

[0041] At the same time, the first collecting tank 114 and the second collecting tank 115 are respectively arranged below the outer box 11 relative to the first position and the second position, which can effectively collect the debris that may fall from the silicone rubber sample during the aging process. In particular, the second collecting tank 115 can not only collect the debris, but also collect the liquid condensed from the acid mist sprayed by the acid mist spraying member 42. This design avoids the debris and liquid from being scattered inside the equipment, prevents pollution and damage to the equipment, ensures the normal operation of the equipment, and also makes the cleaning work more convenient, and only needs to clean the collection tank regularly, which improves the maintenance convenience and service life of the equipment.

[0042] In one embodiment, see Figure 8 The acid mist injection member 42 comprises an atomizing nozzle 421, an acid liquid tank 422 and a pump body 423. The atomizing nozzle 421 is installed in the second installation groove 113. The outlet of the atomizing nozzle 421 is arranged toward the clamping position of the tensioning mechanism 5. The acid liquid tank 422 is used to store acid liquid. The inlet of the pump body 423 is communicated with the acid liquid tank 422, and the outlet of the pump body 423 is communicated with the inlet of the atomizing nozzle 421. In this embodiment, the acid mist injection member 42 can extract the acid liquid in the acid liquid tank 422 through the pump body 423 and transport it to the atomizing nozzle 421 through the combination of the atomizing nozzle 421, the acid liquid tank 422 and the pump body 423, and the atomizing nozzle 421 atomizes the acid liquid into acid mist for spraying. And the outlet of the atomizing nozzle 421 is arranged toward the clamping position of the tensioning mechanism 5, so that the acid mist can accurately act on the silicone rubber sample in the clamping position of the tensioning mechanism 5, thereby accurately simulating the acid mist corrosion environment that the silicone rubber sample may face in actual use, providing reliable experimental conditions for testing the performance of the silicone rubber sample in the acid mist environment, making the test results closer to the actual situation, and improving the accuracy and effectiveness of the test.

[0043] In one embodiment, see Figure 2 The moving channel 111 also has a third position, and the outer box 11 is provided with an operation opening above the third position, and the operation opening is provided with an openable or closable cover 116. The cover 116 can be opened to install and remove the silicone rubber sample.

[0044] In one embodiment, see Figure 2 and Figure 3 An air inlet hole 1161 is provided on the cover plate 116; the silicone rubber tensile stress relaxation experimental device for cable accessories also includes an air suction mechanism 7, the air suction mechanism 7 includes a suction pump 71 and a suction pipe 72, the inlet of the suction pump 71 is connected to one end of the suction pipe 72, and the other end of the suction pipe 72 is connected to the third position in the moving channel 111.

[0045] In this embodiment, after the rain simulation stage is completed (at this time, the acid mist spraying member 42 sprays acid mist into the moving box 12, and the gas in the moving box 12 contains acid mist), the translation mechanism 2 operates to move the moving box 12 from the second position in the moving channel 111 to the third position. After the moving box 12 reaches the third position, the suction pump 71 of the air extraction mechanism 7 is started. Since the inlet of the suction pump 71 is communicated with one end of the suction pipe 72, and the other end of the suction pipe 72 is communicated with the third position in the moving channel 111, the suction pump 71 generates suction force to extract the gas containing acid mist in the moving box 12 to the outside of the device through the suction pipe 72. At the same time of air extraction, fresh air from the outside enters the moving box 12 through the air inlet holes 1161 on the cover plate 116. As the air extraction progresses, the gas containing acid mist in the moving box 12 is gradually extracted, and fresh air is continuously replenished, realizing the replacement of the gas in the moving box 12. After the gas in the moving box 12 is replaced, the translation mechanism 2 operates again to move the moving box 12 from the third position to the first position in the moving channel 111. At this time, the first simulation mechanism 3 starts to work, that is, the first temperature and humidity adjustment member 31 adjusts the temperature and humidity in the moving box 12 to simulate a high-temperature environment, and the ultraviolet emitter 32 emits ultraviolet rays into the moving box 12 to simulate strong ultraviolet radiation, and the high-temperature simulation experiment starts.

[0046] Through the above settings, the interference of the gas containing acid mist generated by the rain simulation experiment on the high-temperature simulation experiment is effectively avoided. The presence of acid mist may change the gas composition, humidity and other conditions of the high-temperature environment, thereby affecting the aging test results of silicone rubber samples under high-temperature conditions. Through air extraction and gas replacement, it is ensured that the high-temperature simulation experiment is carried out in a relatively pure environment, so that the test results can more accurately reflect the aging performance of silicone rubber samples in a high-temperature environment, and the accuracy and reliability of the experimental data are improved.

[0047] In one of the embodiments, please refer to Figures 3-7, the stretching mechanism 5 includes a fixed rod 51, a bottom plate 52, two end plates 53, a double-headed lead screw 54, a handle 55, two moving plates 56 and a guide rod 531. The fixed rod 51 is fixed inside the moving box 12, the bottom plate 52 is fixed to the fixed rod 51, the two end plates 53 are respectively fixed to both ends of the bottom plate 52, both ends of the double-headed lead screw 54 are rotatably arranged on the two end plates 53, one end of the double-headed lead screw 54 is fixed with the handle 55, first screw holes are respectively formed on the two moving plates 56, both ends of the double-headed lead screw 54 are threadedly connected to the first screw holes on the two end plates 53, first clamping members 57 are installed on the end plates 53, the first clamping members 57 are used for clamping one end of the silicone rubber sample 6, tension measuring members 58 are installed on the moving plates 56, a second clamping member 59 is connected to the measuring end of the tension measuring member 58, and the second clamping member 59 is used for clamping the other end of the silicone rubber sample 6. Both ends of the guide rod 531 are fixed to the two end plates 53, and guide holes for the guide rod 531 to pass through are respectively formed on the two moving plates 56.

[0048] In this embodiment, one end of the silicone rubber sample 6 is placed in the first clamping member 57 on the end plate 53 and clamped and fixed by the first clamping member 57. Then the other end of the silicone rubber sample 6 is placed in the second clamping member 59 on the moving plate 56 and also clamped and fixed by the second clamping member 59, so that the silicone rubber sample 6 is in a clamped state. Then the handle 55 at one end of the double-headed lead screw 54 is rotated. Since both ends of the double-headed lead screw 54 are threadedly connected to the first screw holes on the two moving plates 56, and the guide rod 531 passes through the guide holes in the moving plates 56 to play a guiding role, when the handle 55 is rotated to rotate the double-headed lead screw 54, the two moving plates 56 will move towards each other on the double-headed lead screw 54 along the direction of the guide rod 531. When moving towards each other, the silicone rubber sample 6 is stretched until the set stretching rate is reached. The tension measuring member 58 will measure the magnitude of the tension received by the silicone rubber sample 6 in real time and feedback the data. According to the experimental requirements, after adjusting to the appropriate stretching degree, continuously monitor the data change of the tension measuring member 58 and record the tension conditions of the silicone rubber sample 6 at different time periods.

[0049] In this embodiment, through the threaded connection between the double-headed lead screw 54 and the screw holes on the moving plate 56, the position of the moving plate 56 can be accurately adjusted, and thus the stretching degree of the silicone rubber sample 6 can be accurately controlled. The screw drive has high precision and stability, and the silicone rubber sample 6 can be stretched to a specific length or stretching rate according to the experimental requirements, meeting the accurate requirements for the stretching degree in different experiments. And the experiments on multiple silicone rubber samples can be carried out at one time, improving the experimental efficiency.

[0050] In one of the embodiments, please refer to Figures 3-7, the first clamping member 57 includes a first clamping frame 571, a first clamping block 572 and a first locking screw 573. The first clamping frame 571 is fixed to the end plate 53. A second screw hole is formed in the first clamping frame 571. The first clamping block 572 is slidably disposed in the first clamping frame 571. The first locking screw 573 is threadedly connected to the second screw hole, and the first locking screw 573 is rotatably connected to the first clamping block 572. In this embodiment, the first clamping frame 571 is fixed to the end plate 53, providing a stable installation base. The first clamping block 572 is slidably disposed in the first clamping frame 571. By rotating the first locking screw 573, since the first locking screw 573 is threadedly connected to the second screw hole in the first clamping frame 571 and rotatably connected to the first clamping block 572, as the first locking screw 573 is tightened, the first clamping block 572 will move in the first clamping frame 571 and gradually approach the silicone rubber sample 6, thereby firmly clamping it between the first clamping block 572 and the first clamping frame 571. This structure can generate a large clamping force, ensuring that the silicone rubber sample 6 does not loosen or slip during the tensile experiment, guaranteeing the smooth progress of the experiment and the accuracy of the data.

[0051] In one embodiment, please refer to Figures 3-7 , the second clamping member 59 includes a second clamping frame 591, a second clamping block 592 and a second locking screw 593. The second clamping frame 591 is fixed to the measuring end of the tensile force measuring member 58. A third screw hole is formed in the second clamping frame 591. The second clamping block 592 is slidably disposed in the second clamping frame 591. The second locking screw 593 is threadedly connected to the third screw hole, and the second locking screw 593 is rotatably connected to the second clamping block 592. In this embodiment, the second clamping frame 591 is fixed to the measuring end of the tensile force measuring member 58, providing a stable installation position for the entire second clamping member 59. This enables the second clamping member 59 to move stably with the tensile force measuring member 58 during the tensile experiment, ensuring that when the silicone rubber sample 6 is stretched, the force applied to it can be accurately transmitted to the tensile force measuring member 58.

[0052] The present invention also provides a method for testing the tensile stress relaxation of silicone rubber for cable accessories, which is applicable to the cable accessory silicone rubber tensile stress relaxation test device, and includes the following steps: Step 1: Experiment preparation: Fix a plurality of silicone rubber samples 6 on the tensile mechanism 5 in the moving box 12. The tensile mechanism 5 stretches the silicone rubber samples 6 at a predetermined stretching rate and can continuously monitor the tensile force of the silicone rubber samples 6; Step 2: High-temperature simulation stage: Through the translation mechanism 2, the moving box 12 is driven to move to the first position in the moving channel 111. The first temperature and humidity adjustment member 31 is activated, and according to the preset experimental requirements, the temperature and humidity in the moving box 12 are precisely adjusted to simulate a high-temperature environment. At the same time, the ultraviolet emitter 32 is turned on to emit ultraviolet rays into the moving box 12 to simulate strong ultraviolet radiation. The tensioning mechanism 5 continuously monitors and records the tensile force change data of the silicone rubber sample 6 in the high-temperature simulation environment; Step 3: Rain simulation stage: After the preset time, the translation mechanism 2 operates again to move the moving box 12 to the second position in the moving channel 111. The second temperature and humidity adjustment member 41 starts to work to adjust the temperature and humidity in the moving box 12 to create a high-humidity environment similar to that in a rain environment. The acid mist spraying member 42 is activated to spray acid mist into the moving box 12 to simulate the acidity of rainwater. The tensioning mechanism 5 continuously monitors and records the tensile force change data of the silicone rubber sample 6 in the high-temperature and rain simulation environment; Step 4: Cyclic switching and data acquisition: According to the experimental requirements, the state of the moving box 12 between the first position and the second position can be repeatedly switched through the translation mechanism 2 to simulate the alternating occurrence of high-temperature and rain conditions. The tensioning mechanism 5 continuously monitors and records the tensile force change data of the silicone rubber sample 6; Step 5: End of experiment: After completing all the preset experimental cycle times or reaching the experimental time, the translation mechanism 2 moves the moving box 12 back to the initial position, stops the operation of the tensioning mechanism 5, the first simulation mechanism 3, and the second simulation mechanism 4, takes out the silicone rubber sample 6, and ends the experiment. The degree of influence of high temperature, rain, and the switching process between the two environments on the aging process of the silicone rubber is obtained from the tensile force change data of the silicone rubber sample 6 recorded by the tensioning mechanism 5.

[0053] The technical effects of the technical solution provided by this application include: (1) This experimental device can separately simulate the two environmental conditions of high temperature and rain that have a significant impact on the aging of silicone rubber, and can realize the alternating switching of the two environmental conditions, highly restoring the complex environmental change mode faced by silicone rubber products during actual use, making the experimental results more in line with the actual use situation; by stretching the silicone rubber sample 6 through the tensioning mechanism 5 in different simulation environments and during the environmental switching process, and real-time monitoring of the stress relaxation data, it can comprehensively and deeply reveal the tensile stress relaxation characteristics of silicone rubber in a multi-physical field coupling environment, providing strong data support for accurately evaluating the mechanical properties and service life of silicone rubber materials; (2)The inlet of the suction pump 71 is communicated with one end of the suction pipe 72, and the other end of the suction pipe 72 is communicated with the third position in the moving channel 111. When the suction pump 71 works to generate suction, the gas containing acid mist in the moving box 12 is pumped out to the outside of the device through the suction pipe 72. At the same time of pumping air, fresh air from the outside enters the moving box 12 through the air inlet holes 1161 on the cover plate 116. As the pumping air progresses, the gas containing acid mist in the moving box 12 is gradually pumped out, and fresh air is continuously supplemented, realizing the replacement of the gas in the moving box 12; through the above settings, the interference of the gas containing acid mist generated by the rain simulation experiment on the high-temperature simulation experiment is effectively avoided. The presence of acid mist may change the gas composition, humidity and other conditions in the high-temperature environment, thereby affecting the aging test results of the silicone rubber sample under high-temperature conditions. Through air extraction and gas replacement, it is ensured that the high-temperature simulation experiment is carried out in a relatively pure environment, so that the test results can more accurately reflect the aging performance of the silicone rubber sample in the high-temperature environment, improving the accuracy and reliability of the experimental data.

[0054] The specific implementation manners of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and deformations made according to the technical concept of the present application shall be included in the protection scope of the present application.

Claims

1. A silicone rubber tensile stress relaxation experimental device for cable accessories, characterized in that: Comprising: An experimental chamber (1), the experimental chamber (1) includes an outer box (11) and a movable box (12), there is a movable channel (111) inside the outer box (11), the movable box (12) is slidably arranged in the movable channel (111), and the upper end of the movable box (12) is open; A translation mechanism (2), the translation mechanism (2) is connected to the movable box (12) and is used to drive the movable box (12) to move to a first position or a second position in the movable channel (111); A first simulation mechanism (3), the first simulation mechanism (3) includes a first temperature and humidity adjustment member (31) and an ultraviolet emitter (32). When the movable box (12) reaches the first position, the first temperature and humidity adjustment member (31) can adjust the temperature and humidity of the movable box (12), and the ultraviolet emitter (32) is used to emit ultraviolet rays into the movable box (12); A second simulation mechanism (4), the second simulation mechanism (4) includes a second temperature and humidity adjustment member (41) and an acid mist spraying member (42). When the movable box (12) reaches the second position, the second temperature and humidity adjustment member (41) can adjust the temperature and humidity of the movable box (12), and the acid mist spraying member (42) is used to spray acid mist into the movable box (12); and, A stretching mechanism (5), the stretching mechanism (5) is installed in the movable box (12) and is used to clamp and stretch a plurality of silicone rubber samples (6).

2. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 1, characterized in that: The translation mechanism (2) includes a first pulling component (21) and a second pulling component (22). The first pulling component (21) includes a first pulling motor (211), a first winding drum (212), a first pulling rope (213), and a plurality of first guiding wheels (214). The fixed end of the first pulling motor (211) is fixed inside the outer box (11). The first winding drum (212) is coaxially fixed to the output end of the first pulling motor (211). The first pulling rope (213) is wound around the first winding drum (212). The free end of the first pulling rope (213) is connected to one end of the moving box (12). Each of the first guiding wheels (214) is rotatably arranged in the outer box (11) and is used for the first pulling rope (213) to be wound around, so as to guide the extending direction of the first pulling rope (213). The second pulling component (22) includes a second pulling motor (221), a second winding drum (222), a second pulling rope (223), and a plurality of second guiding wheels (224). The fixed end of the second pulling motor (221) is fixed inside the outer box (11). The second winding drum (222) is coaxially fixed to the output end of the second pulling motor (221). The second pulling rope (223) is wound around the second winding drum (222). The free end of the second pulling rope (223) is connected to one end of the moving box (12). Each of the second guiding wheels (224) is rotatably arranged in the outer box (11) and is used for the second pulling rope (223) to be wound around, so as to guide the extending direction of the second pulling rope (223).

3. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 1, characterized in that: A first installation groove (112) is formed above the outer box (11) relative to the first position. The first temperature and humidity adjusting member (31) and the ultraviolet emitter (32) are both installed in the first installation groove (112). A second installation groove (113) is formed above the outer box (11) relative to the second position. The second temperature and humidity adjusting member (41) and the acid mist spraying member (42) are both installed in the second installation groove (113). The lower end of the moving box (12) is open. A first collection groove (114) is formed below the outer box (11) relative to the first position. A second collection groove (115) is formed below the outer box (11) relative to the second position.

4. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 3, characterized in that: The acid mist spraying member (42) includes an atomizing nozzle (421), an acid liquid tank (422), and a pump body (423). The atomizing nozzle (421) is installed in the second installation groove (113). The outlet of the atomizing nozzle (421) faces the clamping position of the stretching mechanism (5). The acid liquid tank (422) is used for storing acid liquid. The inlet of the pump body (423) is communicated with the acid liquid tank (422). The outlet of the pump body (423) is communicated with the inlet of the atomizing nozzle (421).

5. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 3, characterized in that: The moving channel (111) further has a third position. An operation opening is provided above the third position of the outer box (11), and a cover plate (116) that can be opened or closed is provided at the operation opening.

6. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 5, characterized in that: An air inlet hole (1161) is provided on the cover plate (116); The silicone rubber tensile stress relaxation experimental device for cable accessories further includes an air extraction mechanism (7). The air extraction mechanism (7) includes an air suction pump (71) and a suction pipe (72). The inlet of the air suction pump (71) is communicated with one end of the suction pipe (72), and the other end of the suction pipe (72) is communicated with the third position in the moving channel (111).

7. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 1, characterized in that: The tensioning mechanism (5) includes a fixed rod (51), a bottom plate (52), two end plates (53), a double-headed screw rod (54), a handle (55), two moving plates (56) and guide rods (531). The fixed rod (51) is fixed in the moving box (12), the bottom plate (52) is fixed on the fixed rod (51), the two end plates (53) are respectively fixed at both ends of the bottom plate (52), the two ends of the double-headed screw rod (54) are respectively rotatably arranged on the two end plates (53), one end of the double-headed screw rod (54) is fixed with the handle (55), first screw holes are respectively provided on the two moving plates (56), and the two ends of the double-headed screw rod (54) are respectively threadedly connected with the first screw holes on the two end plates (53). First clamping members (57) are installed on the end plates (53), and the first clamping members (57) are used for clamping one end of the silicone rubber sample (6). Tensile force measuring members (58) are installed on the moving plates (56), the measuring ends of the tensile force measuring members (58) are connected with a second clamping member (59), and the second clamping member (59) is used for clamping the other end of the silicone rubber sample (6). The two ends of the guide rod (531) are respectively fixed on the two end plates (53), and guide holes for the guide rod (531) to pass through are respectively provided on the two moving plates (56).

8. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 7, wherein: The first clamping member (57) includes a first clamping frame (571), a first clamping block (572) and a first locking screw (573). The first clamping frame (571) is fixed on the end plate (53), a second screw hole is provided on the first clamping frame (571), the first clamping block (572) is slidably arranged in the first clamping frame (571), the first locking screw (573) is threadedly connected to the second screw hole, and the first locking screw (573) is rotatably connected with the first clamping block (572).

9. The silicone rubber tensile stress relaxation test device for cable accessories according to claim 7, wherein: The second clamping member (59) includes a second clamping frame (591), a second clamping block (592) and a second locking screw (593). The second clamping frame (591) is fixed to the measuring end of the tensile force measuring member (58). A third screw hole is formed in the second clamping frame (591). The second clamping block (592) is slidably arranged in the second clamping frame (591). The second locking screw (593) is threadedly connected to the third screw hole, and the second locking screw (593) is rotatably connected to the second clamping block (592).

10. A method for testing the tensile stress relaxation of silicone rubber for cable accessories, characterized in that: It is applicable to the silicone rubber tensile stress relaxation experiment device for cable accessories as described in any one of claims 1-9, and includes the following steps: Step 1: Experiment preparation: Fix a number of silicone rubber samples (6) on the tensioning mechanism (5) in the moving box (12). The tensioning mechanism (5) stretches the silicone rubber samples (6) at a predetermined stretching rate and can continuously monitor the magnitude of the tensile force of the silicone rubber samples (6). Step 2: High-temperature exposure simulation stage: Through the translation mechanism (2), drive the moving box (12) to move to the first position in the moving channel (111). The first temperature and humidity adjusting member (31) is started, and according to the experimental preset requirements, accurately adjust the temperature and humidity in the moving box (12) to simulate a high-temperature environment. At the same time, the ultraviolet emitter (32) is turned on to emit ultraviolet rays into the moving box (12) to simulate strong ultraviolet radiation. The tensioning mechanism (5) continuously monitors and records the tensile force change data of the silicone rubber samples (6) in the high-temperature exposure simulation environment. Step 3: Rain simulation stage: After a preset time, the translation mechanism (2) operates again to move the moving box (12) to the second position in the moving channel (111). The second temperature and humidity adjusting member (41) starts to work to adjust the temperature and humidity in the moving box (12) to create a high-humidity environment similar to that in the rain environment. The acid mist spraying member (42) is started to spray acid mist into the moving box (12) to simulate the acidity of rainwater. The tensioning mechanism (5) continuously monitors and records the tensile force change data of the silicone rubber samples (6) in the high-temperature and rain simulation environment. Step 4: Cycle switching and data acquisition. According to the experimental requirements, the translation mechanism (2) can repeatedly switch the state of the moving box (12) between the first position and the second position to simulate the alternating recurrence of high-temperature exposure and rain conditions. The tensioning mechanism (5) continuously monitors and records the tensile force change data of the silicone rubber samples (6). Step 5: Experiment end: After completing all preset experimental cycle times or reaching the experimental time, the translation mechanism (2) moves the moving box (12) back to the initial position, stops the operation of the tensioning mechanism (5), the first simulation mechanism (3) and the second simulation mechanism (4), takes out the silicone rubber samples (6), ends the experiment, and obtains the influence degree of high-temperature exposure, rain and the switching process between the two environments on the aging process of silicone rubber from the tensile force change data of the silicone rubber samples recorded by the tensioning mechanism (5).

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