An EVA film tensile testing device

Abstract

This application relates to the field of tensile testing technology and discloses an EVA film tensile testing device, which includes a drive motor and a drive screw. A support plate is provided between the tops of the two columns. The drive screw drives a crossbeam to slide up and down, and the drive motor drives the drive screw to rotate. A test cover is provided on the base, located below the crossbeam. A connecting assembly is provided at the bottom of the crossbeam. The test cover is telescopic, and its top is detachably connected to the crossbeam via the connecting assembly. The test cover is made of high-temperature resistant fireproof cloth and is connected to a heater and an air conditioning unit via pipes. This application allows for convenient observation and adjustment of the gauge length between the upper and lower clamps before clamping the EVA film sample, thereby improving testing efficiency. Furthermore, it allows for tensile testing of samples of different lengths under high and low temperature environments, expanding the applicability of the high and low temperature tensile testing machine.

Description

Technical Field

[0001] This application relates to the field of tensile testing technology, and in particular to an EVA film tensile testing device. Background Technology

[0002] EVA film, also known as EVA hot melt adhesive film, is a hot melt adhesive film product based on ethylene-vinyl acetate copolymer (EVA). It is a colorless, transparent, or hazy polymer with odorless, tasteless, and non-toxic properties. EVA hot melt adhesive film typically contains 60%-90% EVA. This material is solid at room temperature, but melts into a viscous liquid when heated to a certain temperature, and then re-solidifies upon cooling, forming a strong bond. Therefore, EVA film is widely used in material lamination and bonding in various industries, such as shoe material lamination, bag lamination, wallpaper lamination, and automotive interior lamination. Furthermore, due to its excellent adhesion, durability, and optical properties, EVA film is also widely used in solar cell encapsulation and electronic component sealing.

[0003] After the EVA film is manufactured, its tensile properties need to be tested using a tensile testing machine. Since EVA film is also widely used in battery encapsulation and electronic component sealing, it also needs to be suitable for high-temperature applications. Therefore, tensile testing of the EVA film is required under high-temperature conditions.

[0004] Chinese utility model patent CN214096980U discloses a high and low temperature tensile testing machine, which includes a base and two columns. A crossbeam slides vertically between the two columns, and an upper clamp is located in the middle of the crossbeam. A test chamber is located between the crossbeam and the base, with the upper clamp extending into the test chamber. A lower clamp is installed at the bottom of the test chamber. The upper and lower clamps are used to hold the test sample. A servo motor, reducer, and lead screw are installed inside the columns to drive the crossbeam to slide vertically, thereby tensile testing of the test sample. An air duct is provided inside the test chamber, containing a fan, heater, and temperature sensor. An equipment placement box is located on the side of the test chamber, housing an air conditioning unit connected to the air duct via pipes. The heater is used to heat the test chamber, simulating a high-temperature environment for tensile testing; the air conditioning unit is used to cool the test chamber, simulating a low-temperature environment for tensile testing.

[0005] Regarding the aforementioned related technologies, the inventors discovered the following problems: 1. The upper clamp can only slide inside the test chamber. When testing long EVA film samples, the film needs to be stretched a considerable distance before breaking. However, the height of the test chamber is limited, and the film has high extensibility. Therefore, there may be a situation where the film has not yet broken when the upper clamp has slid to the top inside the test chamber, leading to test failure. 2. In this solution, both the upper and lower clamps are fixed inside the test chamber. Before clamping the sample, the gauge distance between the upper and lower clamps needs to be adjusted according to the sample length. After adjustment, the distance between the two clamps needs to be measured with a ruler. However, since both clamps are inside the test chamber, it is inconvenient for the test personnel to perform the adjustment and measurement operations, reducing test efficiency. Summary of the Invention

[0006] To facilitate observation and adjustment of the gauge length between the upper and lower clamps before clamping the EVA film sample, thereby improving testing efficiency, and to expand the applicability of the high and low temperature tensile testing machine by conducting tensile tests on samples of different lengths under high and low temperature environments, this application provides an EVA film tensile testing device.

[0007] The EVA film tensile testing device provided in this application adopts the following technical solution:

[0008] An EVA film tensile testing device includes a base with two columns on it and a lower clamp mounted on the base. A crossbeam is slidably connected between the two columns, and an upper clamp is mounted on the bottom of the crossbeam. The device also includes a heater and an air conditioning unit to provide high-temperature and low-temperature environments for the test, respectively. Additionally, it includes a drive motor and a drive screw. A support plate is positioned between the tops of the two columns. The drive screw is rotatably connected between the base and the support plate and is located within one of the columns. The drive screw drives the crossbeam to slide up and down, and the drive motor drives the drive screw to rotate. A test cover is mounted on the base, located below the crossbeam. A connecting assembly is located at the bottom of the crossbeam. The test cover is retractable, and its top is detachably connected to the crossbeam via the connecting assembly. The test cover is made of high-temperature resistant fireproof cloth and is connected to the heater and air conditioning unit via pipes.

[0009] By adopting the above technical solution, before clamping the EVA film sample, the test hood is first in a retracted state. At this time, both the upper and lower clamps are located above the test hood, and the test hood does not obstruct them, making it easy to observe the distance between the upper and lower clamps. The crossbeam is moved up and down according to the length of the sample to adjust the gauge length between the upper and lower clamps. Then, the distance between them is measured with a ruler. Since there is no obstruction, it is convenient to observe and adjust at the same time, improving the test efficiency. After clamping the EVA film sample between the upper and lower clamps, the top of the test hood can be fixed to the crossbeam through the connecting assembly. At this time, both the upper and lower clamps are located inside the test hood. The test hood is then heated or cooled by a heater and an air conditioning unit, which can provide a high-temperature or low-temperature environment for tensile testing. The drive motor is started, which drives the drive screw to rotate. The drive screw drives the crossbeam to slide upward, and the crossbeam drives the upper clamp to slide upward, thereby stretching the EVA film sample. During the stretching process, the crossbeam causes the test hood to extend, which can be applied to samples with different tensile lengths, expanding the applicability of the high and low temperature tensile testing machine.

[0010] Optionally, an observation plate is hinged between the two columns. The observation plate is made of high-temperature resistant glass and has vertically marked scales. A pointer is horizontally fixed to the middle of the upper clamp, and the zero mark of the scale is aligned with the middle of the lower clamp.

[0011] By adopting the above technical solution, when adjusting the distance between the upper and lower clamps, the height of the upper clamp can be adjusted while observing the position of the pointer on the scale, eliminating the need to measure with a ruler after adjustment. This facilitates the determination of the distance between the upper and lower clamps and improves the efficiency of distance adjustment.

[0012] Optionally, the bottom of the drive screw is rotatably connected to a shaft via a bevel gear set, and the other end of the shaft is fixedly connected to an adjustment handwheel. A switching component is provided on the support plate, which is used to disconnect the drive motor from the drive screw.

[0013] By adopting the above technical solution, during distance adjustment, the drive motor is first disconnected from the drive screw using a switching device. At this time, the drive screw switches from electric drive to manual drive mode. Then, the distance adjustment handwheel is rotated, which drives the rotating shaft to rotate. The rotating shaft drives the drive screw to rotate through the bevel gear set. The drive screw drives the crossbeam to slide up and down, thereby causing the upper clamp to slide. The pointer on the upper clamp indicates the scale on the observation plate. The tester can observe the scale while slowly rotating the distance adjustment handwheel. When the pointer indicates the height that needs to be adjusted, the distance adjustment handwheel is stopped, thus completing the adjustment of the gauge distance between the upper and lower clamps, making the distance adjustment more accurate and easier to control.

[0014] Optionally, a rotating pulley is coaxially fixedly connected to the top of the drive screw, and a drive pulley is coaxially fixedly connected to the rotating shaft of the drive motor. The drive pulley and the rotating pulley are connected by a belt. The width of the drive pulley is greater than the width of the rotating pulley. The switching component includes a cylinder and a clamping block. A mounting plate is also fixedly connected to the support plate. A fixed pulley is rotatably connected to the bottom surface of the mounting plate. The fixed pulley is located above the rotating pulley and is coaxially arranged with the rotating pulley. The diameter of the fixed pulley is the same as the diameter of the rotating pulley. The cylinder telescopic shaft is fixedly connected to the clamping block, and the clamping block is used to clamp the belt.

[0015] By adopting the above technical solution, when tension is applied, the cylinder extends, and the clamping block drives the belt downward to the rotating pulley, which enables the drive motor to drive the drive screw. At this time, the drive screw is driven in electric drive mode, and tensile testing can be performed. When adjusting the distance, the cylinder retracts, and the clamping block drives the belt upward to the fixed pulley. At this time, the drive screw can be rotated by turning the adjustment handwheel, which drives the drive screw in manual drive mode. This makes it easier to control and observe during distance adjustment, improving the accuracy of the adjustment. At the same time, the switching device enables two control modes for a single drive screw, which keeps the structure of the tensile testing device simple while increasing its functionality, thereby enhancing the functionality of the device.

[0016] Optionally, the top and bottom of the test hood are fixedly connected to a support frame. The support frame at the bottom of the test hood is fixedly connected to the base. A hanging rod is provided on the support frame at the top of the test hood. The connecting assembly includes a hook, and the hanging rod is used to hang on the hook.

[0017] By adopting the above technical solution, when connecting the test cover and the crossbeam, the hanging rod can be hung on the hook to complete the connection between the test cover and the crossbeam, which is simple and convenient to operate; when it is necessary to remove the test cover, the hanging rod can be removed from the hook to complete the disassembly of the test cover.

[0018] Optionally, a fixing groove is provided on the crossbeam, the connecting assembly is located in the fixing groove, a fixing box is provided on the top of the crossbeam, the bottom surface of the fixing box is open, the connecting assembly includes a snap-fit ​​rod, the snap-fit ​​rod includes a first snap-fit ​​rod and a second snap-fit ​​rod, the second snap-fit ​​rod is fixedly connected to the top of the first snap-fit ​​rod, the top of the first snap-fit ​​rod is rotatably connected to the fixing box, the hook is fixedly connected to the bottom of the first snap-fit ​​rod, and a slider is vertically slidably connected in the fixing box, the slider is used to drive the second snap-fit ​​rod to rotate.

[0019] By adopting the above technical solution, the slider slides up and down, which drives the second locking rod to rotate up and down, thereby driving the bottom of the first locking rod to rotate towards or away from the hanging rod, and then driving the hook to rotate towards or away from the hanging rod. When the hook rotates towards the hanging rod, the hanging rod is hooked onto the hook, thus completing the fixation of the support frame, that is, completing the installation of the test cover; when the hook rotates away from the hanging rod, the hook disengages from the hanging rod, thereby releasing the fixation of the support frame and allowing the test cover to be removed from the crossbeam.

[0020] Optionally, the top of the slider is fixedly connected to the top surface inside the fixed box by a spring. A positioning rod is rotatably connected inside the fixed box. The positioning rod is located on the side of the slider away from the locking rod. A guide channel is opened on the side of the slider facing the positioning rod. A sliding column is rotatably connected to the bottom of the positioning rod. The sliding column is slidably connected in the guide channel. A first limiting arc surface is provided at the top of the guide channel. A second limiting arc surface is provided at the bottom of the guide channel. Both the first and second limiting arc surfaces are used to fix the sliding column. A push rod is fixedly connected to the bottom surface of the slider. A push block is fixedly connected to the support frame. A hanging rod is fixedly connected to the push block. A guide plate is fixedly connected to the side of the slider facing the locking rod. A limiting groove is vertically opened in the guide plate. A locking pin is fixedly connected to the second locking rod. The locking pin is located in the limiting groove. When the slider slides vertically, the limiting groove and the locking pin are slidably connected.

[0021] By adopting the above technical solution, when the test cover needs to be hung on the crossbeam, the support frame is lifted upward, causing the push block to push the push rod upward. The push rod pushes the slider upward, and at this time, the sliding column on the positioning rod slides downward in the guide channel. When it slides into the first limiting arc surface, the slider locks, and at the same time, the guide plate pushes the bottom of the locking rod to rotate towards the hanging rod, so that the hook locks the hanging rod, thereby hanging the support frame on the crossbeam and completing the installation of the test cover. When the support frame needs to be removed, the support frame is pushed upward again, the push block pushes the push rod upward, and the push rod pushes the slider upward, so that the sliding column disengages from the second limiting arc surface. At this time, due to the elastic force of the spring, when the support frame is released, the sliding column automatically slides into the first limiting arc surface, causing the slider to slide downward. The slider causes the guide plate to slide downward, and the guide plate pushes the locking rod to rotate, causing its bottom to move away from the hanging rod, thereby disengaging the hook from the hanging rod, and the support frame can be removed.

[0022] When installing and removing the test cover, simply press the support frame upwards twice to install or remove it, thus enabling the installation and removal of the test cover. The operation is simple and convenient. Furthermore, test personnel can choose to install or remove the test cover according to testing needs. When testing at room temperature, the test cover can be removed for easy observation and operation. When testing in high or low temperature environments, the test cover can be installed, facilitating the provision of high and low temperature environments and improving the applicability and convenience of the tensile testing device.

[0023] Optionally, the width of the guide channel is greater than the diameter of the slide column. The guide channel includes an inner guide surface and an outer guide surface, forming a channel for the slide column to slide between the inner and outer guide surfaces. Both the inner and outer guide surfaces are rhomboid in shape. The first limiting arc surface is located at the top of the outer guide surface. A first guide slope is formed at the top of the inner guide surface. The first guide slope is located directly below the first limiting arc surface. The second limiting arc surface is formed by bending upward from the bottom of the inner guide surface. The bottom of the outer guide surface bends towards the second limiting arc surface to form a second guide slope and a third guide slope. The third guide slope is located directly below the second limiting arc surface. The second guide slope is offset from the center of the second limiting arc surface in the vertical direction. A stopping surface is provided between the second guide slope and the outer guide surface.

[0024] By adopting the above technical solution, when installing the test cover, pressing the support frame upwards causes the push block to push the push rod upwards, which in turn pushes the slider upwards. At this time, the sliding column on the positioning rod slides downwards within the guide channel. A pause is felt when it reaches the second guide slope, at which point the support frame can be released. Under the action of the spring, the sliding column automatically slides into the first limit arc surface, locking the slider. Simultaneously, the guide plate pushes the bottom of the locking rod to rotate closer to the hanging rod, causing the hook to engage the hanging rod. The test personnel can detect the completion of the installation operation through the pause, serving as a reminder. Function: When the support frame needs to be removed, press the support frame upward again. The push block pushes the push rod to slide upward, and the push rod pushes the slider to slide upward, causing the sliding column to disengage from the second limiting arc surface. At this time, due to the guiding effect of the third guide slope and the elastic force of the spring, the sliding column automatically slides into the first limiting arc surface, causing the slider to slide downward. At the same time, the slider causes the guide plate to slide downward, and the guide plate pushes the locking rod to rotate, causing its bottom to move away from the hanging rod, thereby causing the hook to disengage from the hanging rod. At this time, the test personnel can know that the disassembly has been completed, and the test cover can be removed.

[0025] Optionally, the observation plate and one of the columns are connected by a spring pin. The spring pin includes a spring hanging ring and a limiting plate. The spring hanging ring is disposed on the observation plate, and the limiting plate is disposed on the column. The spring hanging ring is used to hang on the limiting plate. The test cover has a vertically opened observation port on the side facing the observation plate. The observation port is used to observe the tensile state of the EVA film sample.

[0026] By adopting the above technical solution, when conducting tensile tests in high and low temperature environments, the spring hanging ring can be stretched and then hung on the limiting plate to fix the observation plate, so that the observation port is tightly fitted with the observation plate, improving the heat preservation of the test cover; at the same time, the opening of the observation port also facilitates the observation of the tensile state of the EVA film sample during the stretching process, which can both ensure the heat preservation of the test cover and facilitate the observation of the internal condition of the test cover.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. Before clamping the EVA film sample, first retract the test chamber. At this point, both the upper and lower clamps are positioned above the test chamber, which provides unobstructed view, allowing for easy observation of the distance between them. Adjust the gauge length between the upper and lower clamps by moving the crossbeam up and down according to the sample length. Then, measure the distance with a ruler. Since there are no obstructions, simultaneous observation and adjustment are possible, improving testing efficiency. After clamping the EVA film sample between the upper and lower clamps, the top of the test chamber can be fixed to the crossbeam via a connecting assembly. At this point, both clamps are inside the test chamber. Heaters and air conditioning units are used to heat or cool the inside of the test chamber, providing a high- or low-temperature environment for tensile testing. Start the drive motor, which rotates the drive screw, causing the crossbeam to slide upwards. The crossbeam then causes the upper clamp to slide upwards, stretching the EVA film sample. During the stretching process, the crossbeam extends the test chamber, making it suitable for samples of different tensile lengths and expanding the applicability of the high and low temperature tensile testing machine.

[0029] 2. When adjusting the distance, first use the switching device to disconnect the drive motor from the drive screw. At this time, the drive screw switches from electric drive to manual drive mode. Then, turn the adjustment handwheel. The adjustment handwheel drives the rotating shaft to rotate. The rotating shaft drives the drive screw to rotate through the bevel gear set. The drive screw drives the crossbeam to slide up and down, thereby causing the upper clamp to slide. The pointer on the upper clamp indicates the scale on the observation plate. The tester can observe the scale while slowly turning the adjustment handwheel. When the pointer indicates the height that needs to be adjusted, stop turning the adjustment handwheel. This completes the adjustment of the gauge distance between the upper and lower clamps, making the adjustment more accurate and easier to control.

[0030] 3. When installing and removing the test cover, simply press the support frame upwards twice to install and remove the support frame, thus enabling the installation and removal of the test cover. The operation is simple and convenient. At the same time, the test personnel can choose to install or remove the test cover according to the testing requirements. When conducting tests at room temperature, the test cover can be removed for easy observation and operation. When conducting tests in high temperature and low temperature environments, the test cover can be installed, thereby facilitating the provision of high temperature and low temperature environments and improving the applicability and convenience of the tensile testing device. Attached Figure Description

[0031] Figure 1 This is a front view of the overall structure of an embodiment of this application;

[0032] Figure 2 This is a partial structural front view of an embodiment of this application, mainly used to show the driving component and the pitch adjustment component;

[0033] Figure 3 This is a partial structural cross-sectional view of an embodiment of this application, mainly used to show the connecting components;

[0034] Figure 4 This is a left view of a partial structure of an embodiment of this application, mainly used to show the guide passage.

[0035] Explanation of reference numerals in the attached drawings: 11. Base; 12. Column; 13. Crossbeam; 131. Fixing groove; 132. Slide groove; 14. Upper clamp; 15. Lower clamp; 2. Drive assembly; 21. Drive motor; 22. Drive screw; 23. Support plate; 24. Guide rod; 25. Mounting plate; 26. Rotating pulley; 27. Drive pulley; 3. Adjustment assembly; 31. Switching component; 311. Cylinder; 312. Clamping block; 313. Clamping groove; 314. Fixing pulley; 321. Adjustment handwheel; 322. Rotating shaft; 323. Bevel gear set; 33. Observation plate; 34. Spring pin; 341. Spring hanging ring; 342. Limiting plate; 351. Indicating scale; 352. 4. Pointer; 41. Test cover; 42. Support frame; 5. Observation port; 5. Connecting assembly; 51. Slider; 52. Spring; 53. Positioning rod; 54. Sliding column; 55. Guide channel; 551. Inner guide surface; 5511. First guide slope; 5512. Second limiting arc surface; 552. Outer guide surface; 5521. First limiting arc surface; 5522. Second guide slope; 5523. Third guide slope; 5524. Stop surface; 56. Push rod; 57. Snap-fit ​​rod; 571. First snap-fit ​​rod; 572. Second snap-fit ​​rod; 573. Hook; 574. Snap-fit ​​pin; 58. Guide plate; 581. Limiting groove; 591. Push block; 592. Hanging rod; 6. Fixing box. Detailed Implementation

[0036] The following is in conjunction with the appendix Figure 1-4This application will be described in further detail.

[0037] This application discloses an EVA film tensile testing device.

[0038] Reference Figure 1 and Figure 2 An EVA film tensile testing device includes a base 11, on which two columns 12 are vertically mounted. A crossbeam 13 is vertically slidably connected between the two columns 12. An upper clamp 14 is mounted on the bottom surface of the crossbeam 13, and a lower clamp 15 is fixedly connected to the base 11. A drive assembly 2 is provided between the two columns 12 to drive the crossbeam 13 to move up and down, thereby causing the upper clamp 14 to move up and down. An adjustment assembly 3 is also provided on the columns 12 to adjust the distance between the upper clamp 14 and the lower clamp 15 before stretching the EVA film sample. A test cover 4 is provided between the crossbeam 13 and the base 11. The test cover 4 is retractable, and its bottom is connected to a heater and an air conditioning unit through a pipe to provide a high-temperature or low-temperature environment. The bottom of the test cover 4 is fixedly connected to the base 11, and the top is provided with a connecting component 5. When only a tensile test needs to be performed at room temperature, the test cover 4 is in a retracted state and placed on the base 11. When a tensile test needs to be performed at different temperatures, the test cover 4 is stretched and installed below the crossbeam 13 through the connecting component 5, so that the upper clamp 14 and the lower clamp 15 are both located inside the test cover 4. During the stretching process, the test cover 4 can slide upward together with the upper clamp 14, thereby adapting to tensile tests of different sample lengths.

[0039] Reference Figure 1 and Figure 2The drive assembly 2 includes a drive motor 21 and a drive screw 22. A support plate 23 is fixedly connected between the tops of the two columns 12. The drive screw 22 is rotatably connected between the base 11 and the support plate 23 and is located inside one of the columns 12. The drive screw 22 is vertically oriented. One end of the crossbeam 13 is threadedly connected to the drive screw 22. A guide rod 24 is provided inside the other column 12. The guide rod 24 is vertically oriented and fixedly connected between the base 11 and the support plate 23. The guide rod 24 passes through the other end of the crossbeam 13 and guides the crossbeam 13. A mounting plate 25 is fixedly connected to the top of the support plate 23. A drive motor 21 is fixedly connected to the mounting plate 25. The top of the drive screw 22 extends out of the support plate 23 and is coaxially fixedly connected to a rotating pulley 26. The drive motor 21 has its rotating shaft facing downwards and is coaxially fixedly connected to a drive pulley 27. The width of the drive pulley 27 is greater than the width of the rotating pulley 26. The drive pulley 27 and the rotating pulley 26 are connected by a belt. When stretching the EVA film sample, the drive motor 21 drives the drive screw 22 to rotate via the belt. The drive screw 22 drives the crossbeam 13 to slide vertically, thereby causing the upper clamp 14 to slide away from the lower clamp 15 to perform a tensile test on the EVA film.

[0040] Reference Figure 1 and Figure 2 The pitch adjustment assembly 3 includes a switching component 31, a pitch adjustment handwheel 321, and an observation plate 33. The switching component 31 is mounted on the support plate 23 and is used to disconnect the drive motor 21 from the drive screw 22. The bottom of the drive screw 22 is rotatably connected to a rotating shaft 322 via a bevel gear set 323. The shaft 322 is perpendicular to the axis of the drive screw 22 and extends out of the column 12. The pitch adjustment handwheel 321 is coaxially fixedly connected to the rotating shaft 322. The observation plate 33 is located between the two columns 12 and is hinged to one of the columns 12, and connected to the other column 12 via a spring pin 34. The observation plate 33 is made of high-temperature resistant glass. The observation plate 33 is located on one side of the front of the column 12. The observation plate 33 has a vertically marked indicator scale 351 on the side away from the crossbeam 13. The zero mark of the indicator scale 351 is aligned with the middle position of the lower clamp 15. A pointer 352 is fixedly connected to the middle position of the upper clamp 14. The pointer 352 is set horizontally and is used to point to the indicator scale 351.

[0041] Before clamping the EVA film sample, the gauge length between the upper and lower clamps needs to be adjusted according to the length of the stretched sample. First, use the switch 31 to disconnect the drive motor 21 from the drive screw 22. Then, rotate the adjustment handwheel 321. The adjustment handwheel 321 drives the rotating shaft 322 to rotate. The rotating shaft 322 drives the drive screw 22 to rotate through the bevel gear set 323. At this time, the drive screw 22 switches from electric drive to manual drive mode. The drive screw 22 drives the crossbeam 13 to slide up and down, thereby driving the upper clamp 14 to slide. The pointer 352 on the upper clamp 14 indicates the indicator scale 351 on the observation plate 33. The tester can observe the scale while slowly rotating the adjustment handwheel 321. When the pointer 352 indicates the height that needs to be adjusted, stop rotating the adjustment handwheel 321, thereby completing the adjustment of the gauge length between the upper and lower clamps.

[0042] Reference Figure 1 The switching component 31 includes a cylinder 311 and a clamping block 312. A fixed pulley 314 is rotatably connected to the bottom surface of the mounting plate 25. The fixed pulley 314 is located above the rotating pulley 26 and is coaxially arranged with the rotating pulley 26. The diameter of the fixed pulley 314 is the same as the diameter of the rotating pulley 26. A clamping groove 313 is formed in the clamping block 312, and the belt is located in the clamping groove 313. The cylinder 311 is fixedly connected to the mounting plate 25, and the telescopic shaft of the cylinder 311 is arranged downward. The telescopic shaft of the cylinder 311 is fixedly connected to the clamping block 312, and the cylinder 311 is used to drive the clamping block 312 to move up and down. During stretching, cylinder 311 extends, driving the belt downwards onto the rotating pulley 26 via clamping block 312, which in turn drives the drive motor 21 to drive the lead screw. During adjustment, cylinder 311 retracts, driving the belt upwards onto the fixed pulley 314 via clamping block 312, which in turn rotates the adjustment handwheel 321 to drive the lead screw. The switching element 31 allows for switching the drive screw 22 from electric to manual operation, making it easier for the operator to control the adjustment of the distance between the upper and lower clamps, facilitating observation and operation simultaneously, and improving the accuracy of the adjustment.

[0043] Reference Figure 1 The spring pin 34 includes a spring hanging ring 341 and a limiting plate 342. The spring hanging ring 341 is connected to the observation plate 33 by bolts, and the limiting plate 342 is connected to the column 12 by bolts. When fixing the observation plate 33, the spring hanging ring 341 is stretched and then hung on the limiting plate 342, thereby completing the fixing of the observation plate 33.

[0044] Reference Figure 2The test chamber 4 has support frames 41 fixedly connected to both its top and bottom surfaces. The support frame 41 on the bottom surface of the test chamber 4 is fixedly connected to the base 11, and the support frame 41 on the top surface of the test chamber 4 can be connected to the crossbeam 13 via the connecting assembly 5. The test chamber 4 has a vertically opening 42 facing the observation plate 33, which is used to observe the tensile state of the EVA film sample. The test chamber 4 is foldable to achieve expansion and contraction, and is made of high-temperature resistant fireproof cloth.

[0045] Reference Figure 2 , Figure 3 and Figure 4 The connecting components 5 are configured in two sets, symmetrically arranged between the drive screw 22 and the guide rod 24. Each end of the top surface of the crossbeam 13 has a vertically opening fixing groove 131, and the two sets of connecting components 5 are located within the two fixing grooves 131 respectively. A fixing box 6 is fixedly connected to the top surface of the crossbeam 13. The bottom surface of the fixing box 6 is open, and the fixing box 6 communicates with the fixing groove 131. Both sets of connecting components 5 are located within the fixing box 6 and at both ends of the fixing box 6. The connecting components 5 include a slider 51, which is vertically slidably connected to the fixing box 6 and the fixing groove 131. The top of the slider 51 is fixedly connected to the top surface of the inner wall of the fixing box 6 via a spring 52. A positioning rod 53 is hinged to the top surface of the inner wall of the fixing box 6. A sliding column 54 is rotatably connected to the bottom end of the positioning rod 53. A guide channel 55 is opened on the side of the slider 51 near the positioning rod 53, and the sliding column 54 at the bottom of the positioning rod 53 is slidably connected within the guide channel 55. A push rod 56 is fixedly connected to the bottom surface of the slider 51. Only when the push rod 56 is pushed towards the spring 52 can the slider 54 slide in the guide channel 55. Due to the action of the spring 52, the slider 54 can be locked in the guide channel 55.

[0046] Reference Figure 4 The width of the guide channel 55 is greater than the diameter of the slide column 54. The guide channel 55 includes an inner guide surface 551 and an outer guide surface 552, forming a channel for the slide column 54 to slide between the inner guide surface 551 and the outer guide surface 552. Both the inner guide surface 551 and the outer guide surface 552 are rhomboid in shape. A first limiting arc surface 5521 is formed at the top of the outer guide surface 552, and a first guide slope 5511 is formed at the top of the inner guide surface 551. The first guide slope 5511 is located directly below the first limiting arc surface 5521. The bottom of the guide surface 551 bends upward to form a second limiting arc surface 5512. The bottom of the outer guide surface 552 bends towards the second limiting arc surface 5512 to form a second guide slope 5522 and a third guide slope 5523. The third guide slope 5523 is located directly below the second limiting arc surface 5512. The second guide slope 5522 is offset from the center of the second limiting arc surface 5512 in the vertical direction. A stopping surface 5524 is provided between the second guide slope 5522 and the outer guide surface 552.

[0047] Reference Figure 3and Figure 4 When the push rod 56 is not subjected to pushing force, the spring 52 is in a telescopic state, and the sliding column 54 is engaged within the first limiting arc surface 5521. When the push rod 56 is pushed upward, the sliding column 54 disengages from the first limiting arc surface 5521 and slides along the first guide slope 5511. When the sliding column 54 abuts against the stopping surface 5524, the push rod 56 is released. Due to the elastic force of the spring 52, the slider 51 is pushed downward. At this time, due to the guidance of the second guide slope 5522, the sliding column 54 automatically slides to the second limiting arc surface 5521. Inside 512, the positioning rod 53 is locked, that is, the slider 51 is locked; when it is necessary to unlock the slider 51, push the push rod 56 again, the slider 51 slides upward, the sliding column 54 abuts against the third guide inclined surface 5523 and slides along the third guide inclined surface 5523. During this period, due to the elastic force of the spring 52, the slider 51 slides downward. When the slider 51 slides to the point where the sliding column 54 is engaged in the first limiting arc surface 5521, the push rod 56 is released, the positioning rod 53 is locked, that is, the slider 51 is locked, and the reset of the slider 51 is completed.

[0048] Reference Figure 3 The fixed box 6 is provided with a snap-fit ​​rod 57, which includes a first snap-fit ​​rod 571 and a second snap-fit ​​rod 572. The second snap-fit ​​rod 572 is fixedly connected to the top of the first snap-fit ​​rod 571. The top of the first snap-fit ​​rod 571 is rotatably connected to the fixed box 6. The slider 51 is fixedly connected to a guide plate 58 on the side away from the positioning rod 53. The guide plate 58 is U-shaped. The second snap-fit ​​rod 572 is rotatably connected to the guide plate 58. A snap-fit ​​pin 574 is fixedly connected to the second snap-fit ​​rod 572. Limit grooves 581 are vertically opened on both sides of the guide plate 58. The slider 51 slides up and down, causing the guide plate 58 to slide up and down. When the slider 51 slides upward until it abuts against the bottom wall of the limiting groove 581 and the locking pin 574, the slider 51 continues to slide upward, which can drive the second locking rod 572 to rotate, thereby causing the bottom of the first locking rod 571 to rotate towards the push rod 56; when the slider 51 slides downward until it abuts against the top wall of the limiting groove 581 and the locking pin 574, the slider 51 continues to slide downward, which can drive the second locking rod 572 to rotate, thereby causing the bottom of the first locking rod 571 to rotate away from the push rod 56.

[0049] Reference Figure 3 and Figure 4The bottom of the first connecting rod 571 is fixedly connected to a hook 573. At both ends of the support frame 41 at the top of the test cover 4, push blocks 591 are fixedly connected to two sets of connecting components 5 respectively. A hanging rod 592 is fixedly connected to the side of the push block 591 facing the other push block 591. The two hanging rods 592 are respectively used to hang on the two hooks 573. A vertical groove 132 is provided on the bottom surface of the crossbeam 13 for the support frame 41 to slide. In the horizontal direction, the hanging rod 592 is located between the corresponding push rod 56 and the hook 573. When the test cover 4 needs to be hung on the crossbeam 13, pull the support frame 41 at the top of the test chamber into the slide groove 132. The push block 591 pushes the push rod 56 upward, and the push rod 56 pushes the slider 51 to slide upward. At this time, the slide column 54 on the positioning rod 53 slides downward in the guide channel 55. When it slides to the second guide inclined surface 5522, there is a pause. At this time, the support frame 41 is released. Under the action of the spring 52, the slide column 54 slides into the first limiting arc surface 5521, locking the slider 51. At the same time, the guide plate 58 also pushes the bottom of the snap-fit ​​rod 57 to rotate towards the hanging rod 592, so that the hook 573 snaps into the hanging rod 592, thereby hanging the support frame 41 on the crossbeam 13, so that the test cover 4 can slide upward with the crossbeam 13. The test cover 4 is stretched accordingly, so it can be used for tensile testing of samples of different lengths.

[0050] When the support frame 41 needs to be removed, push the support frame 41 upward. The push block 591 pushes the push rod 56 to slide upward. The push rod 56 pushes the slider 51 to slide upward, so that the slide column 54 disengages from the second limiting arc surface 5512. At this time, due to the guiding effect of the third guide slope 5523 and the elastic force of the spring 52, when the support frame 41 is released, the slide column 54 automatically slides into the first limiting arc surface 5521, causing the slider 51 to slide downward. The slider 51 causes the guide plate 58 to slide downward. The guide plate 58 pushes the locking rod 57 to rotate, so that its bottom moves away from the hanging rod 592, thereby causing the hook 573 to disengage from the hanging rod 592. The support frame 41 can then be removed, and the test cover 4 can be retracted and folded, thus facilitating the disassembly of the test cover 4.

[0051] The implementation principle of the EVA film tensile testing device in this application embodiment is as follows: before performing tensile testing on the EVA film sample, it is necessary to adjust the gauge length between the upper and lower clamps according to the length of the tensile sample. During the adjustment, first, start the cylinder 311 to retract it. The cylinder 311 drives the belt to move upward to the fixed pulley 314 via the clamping block 312. Then, switch the drive screw 22 from electric drive to manual drive mode. At this time, rotate the adjustment handwheel 321. The adjustment handwheel 321 drives the rotating shaft 322 to rotate. The rotating shaft 322 drives the drive screw 22 to rotate via the bevel gear set 323. The drive screw 22 drives the crossbeam 13 to slide up and down, thereby driving the upper clamp 14 to slide. The pointer 352 on the upper clamp 14 indicates the indicator scale 351 on the observation plate 33. The tester can observe the scale while slowly rotating the adjustment handwheel 321. When the pointer 352 indicates the height that needs to be adjusted, stop rotating the adjustment handwheel 321, thereby completing the adjustment of the gauge length between the upper and lower clamps.

[0052] Then, cylinder 311 is activated to extend it. Cylinder 311, via clamping block 312, moves the belt downwards onto rotating pulley 26. At this time, drive screw 22 switches from manual to electric mode. The observation plate 33 is opened, and the EVA film sample is clamped between the upper and lower clamps. If only a room temperature tensile test is required, the test can begin immediately. Drive motor 21 rotates drive screw 22, which in turn drives beam 13 to slide upwards. Beam 13 then drives upper clamp 14 to slide upwards, thus performing a tensile test on the sample.

[0053] When tensile testing is required in high or low temperature environments, the support frame 41 at the top of the test chamber 4 is mounted on the crossbeam 13 via the connecting assembly 5. The observation plate 33 is closed, and the opening of the test chamber 4 is flush with the observation plate 33, thus sealing the test chamber 4. Both the upper and lower clamps are located inside the test chamber 4. A heater and an air conditioning unit are used to heat or cool the inside of the test chamber 4, providing a high or low temperature environment for the tensile test. During tensile testing, the test chamber 4 extends as the crossbeam 13 moves upward, making it suitable for samples with different tensile lengths.

[0054] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An EVA film tensile testing device, comprising a base (11), two columns (12) disposed on the base (11), a lower clamp (15) mounted on the base (11), a crossbeam (13) slidably connected between the two columns (12), an upper clamp (14) mounted on the bottom surface of the crossbeam (13), and further comprising a heater and an air conditioning unit, used to provide a high-temperature environment and a low-temperature environment for the test, respectively, characterized in that: Includes a drive motor (21) and a drive screw (22). A support plate (23) is provided between the tops of the two columns (12). The drive screw (22) is rotatably connected between the base (11) and the support plate (23) and is located within one column (12). The drive screw (22) is used to drive the crossbeam (13) to slide up and down. The drive motor (21) is used to drive the drive screw (22) to rotate. A test cover (4) is provided on the base (11). The test cover (4) is located below the crossbeam (13). A connecting component (5) is provided at the bottom of the crossbeam (13). The test cover (4) is telescopic. The top of the test cover (4) is detachably connected to the crossbeam (13) through the connecting component (5). Made of high-temperature fireproof cloth, the test hood (4) is connected to the heater and air conditioning unit through pipes. The top and bottom of the test hood (4) are fixedly connected to support frames (41). The support frame (41) at the bottom of the test hood (4) is fixedly connected to the base (11). A hanging rod (592) is provided on the support frame (41) at the top of the test hood (4). The connecting component (5) includes a hook (573). The hanging rod (592) is used to hang on the hook (573). A fixing groove (131) is opened on the crossbeam (13). The connecting component (5) is located in the fixing groove (131). A fixing box (6) is provided on the top of the crossbeam (13). The bottom surface of the fixing box (6) is open. The system includes a locking rod (57), which comprises a first locking rod (571) and a second locking rod (572). The second locking rod (572) is fixedly connected to the top of the first locking rod (571). The top of the first locking rod (571) is rotatably connected to a fixed box (6). A hook (573) is fixedly connected to the bottom of the first locking rod (571). A slider (51) is vertically slidably connected inside the fixed box (6). The slider (51) is used to drive the second locking rod (572) to rotate. The top of the slider (51) is fixedly connected to the top surface inside the fixed box (6) by a spring (52). A positioning rod (53) is rotatably connected inside the fixed box (6). The positioning rod (53) is located on the back of the slider (51). On the side away from the locking rod (57), the slider (51) has a guide channel (55) facing the positioning rod (53). The bottom of the positioning rod (53) is rotatably connected to a sliding column (54). The sliding column (54) is slidably connected in the guide channel (55). The top of the guide channel (55) is provided with a first limiting arc surface (5521), and the bottom of the guide channel (55) is provided with a second limiting arc surface (5512). The first limiting arc surface (5521) and the second limiting arc surface (5512) are both used to fix the sliding column (54). The bottom surface of the slider (51) is fixedly connected to a push rod (56). The support frame (41) is fixedly connected to a push block (591). The hanging rod (592) is fixedly connected to the push block (591).A guide plate (58) is fixedly connected to the slider (51) facing the locking rod (57). A limiting groove (581) is vertically formed in the guide plate (58). A locking pin (574) is fixedly connected to the second locking rod (572). The locking pin (574) is located in the limiting groove (581). When the slider (51) slides vertically, the limiting groove (581) and the locking pin (574) are slidably connected.

2. The EVA film tensile testing device according to claim 1, characterized in that: An observation plate (33) is hinged between the two columns (12). The observation plate (33) is made of high-temperature resistant glass. The observation plate (33) is vertically marked with an indicator scale (351). A pointer (352) is horizontally fixedly connected to the middle of the upper clamp (14). The zero mark of the indicator scale (351) is aligned with the middle position of the lower clamp (15).

3. The EVA film tensile testing device according to claim 2, characterized in that: The bottom of the drive screw (22) is rotatably connected to a rotating shaft (322) via a bevel gear set (323). The other end of the rotating shaft (322) is fixedly connected to an adjustment handwheel (321). A switching component (31) is provided on the support plate (23). The switching component (31) is used to disconnect the drive motor (21) from driving the drive screw (22).

4. The EVA film tensile testing device according to claim 3, characterized in that: The top of the drive screw (22) is coaxially fixedly connected to a rotating pulley (26), and the drive motor (21) is coaxially fixedly connected to a drive pulley (27). The drive pulley (27) and the rotating pulley (26) are connected by a belt. The width of the drive pulley (27) is greater than the width of the rotating pulley (26). The switching component (31) includes a cylinder (311) and a clamping block (312). The support plate (23) is also fixedly connected to an mounting plate (25). The bottom surface of the mounting plate (25) is rotatably connected to a fixed pulley (314). The fixed pulley (314) is located above the rotating pulley (26) and is coaxially arranged with the rotating pulley (26). The diameter of the fixed pulley (314) is the same as the diameter of the rotating pulley (26). The telescopic shaft of the cylinder (311) is fixedly connected to the clamping block (312). The clamping block (312) is used to clamp the belt.

5. The EVA film tensile testing device according to claim 1, characterized in that: The width of the guide channel (55) is greater than the diameter of the slide column (54). The guide channel (55) includes an inner guide surface (551) and an outer guide surface (552). A channel for the slide column (54) to slide is formed between the inner guide surface (551) and the outer guide surface (552). Both the inner guide surface (551) and the outer guide surface (552) are rhomboid in shape. The first limiting arc surface (5521) is located at the top of the outer guide surface (552). A first guide slope (5511) is provided at the top of the inner guide surface (551). The first guide slope (5511) is located at the top of the first limiting arc surface (5521). Below, the second limiting arc surface (5512) is formed by bending the bottom of the inner guide surface (551) upwards. The bottom of the outer guide surface (552) bends towards the second limiting arc surface (5512) to form a second guide slope (5522) and a third guide slope (5523). The third guide slope (5523) is located directly below the second limiting arc surface (5512). The second guide slope (5522) is offset from the center of the second limiting arc surface (5512) in the vertical direction. A stopping surface (5524) is provided between the second guide slope (5522) and the outer guide surface (552).

6. The EVA film tensile testing device according to claim 2, characterized in that: The observation plate (33) and one of the columns (12) are connected by a spring pin (34). The spring pin (34) includes a spring hanging ring (341) and a limiting plate (342). The spring hanging ring (341) is set on the observation plate (33), and the limiting plate (342) is set on the column (12). The spring hanging ring (341) is used to hang on the limiting plate (342). The test cover (4) has a vertically opened observation port (42) facing the observation plate (33). The observation port (42) is used to observe the tensile state of the EVA film sample.

Images