An automatic detection device for the tensile strength of PE protective film

Abstract

The invention relates to an automatic detection device for the tensile resistance of a PE protective film in the field of detection equipment. Before the test, a uniform water flow sprayed from a water spray pipe forms a water film on the surface of a vertically released film body, and the surface tension of the water film is used to repair the wrinkles on the surface of the film body, thereby improving the surface flatness of the film body, and the gravity of the water film itself is used to improve the verticality of the film body, thereby improving the accuracy of subsequent tensile testing. In addition, after the static state is completed, the film body containing the water film is clamped by an upper clamping mechanism and a lower clamping mechanism, and then the water film is blown to remove the water film, thereby reducing the restoration of the wrinkles of the film body caused by dehydration. In addition, through the mutual cooperation of an upper clamping mechanism, an upper lifting mechanism, a lower clamping mechanism and a lower lifting mechanism, the waste film after the test is pulled, cleaned and re-loaded, thereby realizing automatic multiple tensile testing, facilitating multiple data comparisons and improving the accuracy of the test.

Description

Technical Field

[0001] The invention relates to a PE film performance testing device, in particular to an automatic testing device for the tensile strength resistance of a PE protective film applied in the field of testing equipment. Background Art

[0002] PE protective film is a protective material based on special polyethylene (PE) plastic film. It is widely used in various fields such as construction, automobiles, furniture, electronic products, etc. due to its excellent corrosion resistance, waterproofness, wear resistance, and pressure resistance. It can effectively prevent these materials from being contaminated, corroded, and scratched during production, transportation, storage, and use, thereby protecting their original smoothness and beauty, and improving product quality and market competitiveness.

[0003] During the production process, it is crucial to test the tensile properties of PE plastic protective film. This is mainly evaluated through tensile strength testing, that is, measuring the breaking strength of the film under tensile force to ensure that it is not easy to break during use. The testing method includes using a professional tensile testing machine, fixing the sample on the testing machine, and then applying gradually increasing tensile force until the sample breaks. The tensile force at this time is recorded as the tensile strength.

[0004] The existing PE plastic protective film has wrinkles on its surface during testing. When stretched, the stress state of the cross section at the location of the wrinkles is uneven. Specifically, the position near the wrinkles is more likely to break due to the concentrated force, resulting in inaccurate tensile test results. Summary of the invention

[0005] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the existing tensile testing machine cannot handle the wrinkles on the surface of the PE protective film, resulting in inaccurate test results.

[0006] In order to solve the above problems, the present invention provides an automatic detection device for the tensile strength of PE protective film, comprising a base and a controller; the base is fixedly connected to a dust cover, the upper end of the dust cover is fixedly connected to a winding device, and a film body extending into the dust cover is wound on the winding device; the dust cover is provided with an upper clamping mechanism and a lower clamping mechanism for clamping the film body, the upper clamping mechanism is connected to an upper lifting mechanism, the lower clamping mechanism is connected to a lower lifting mechanism, and a leveling device for leveling the film body is provided between the upper clamping mechanism and the lower clamping mechanism; the leveling device comprises a pair of inner clamping plates symmetrically arranged on both sides of the film body, and the inner side of the lower part of the inner clamping plate is fixed A water spray pipe is connected, and a mesh plate is nested on the side of the water spray pipe facing the membrane body. A water inlet pipe is connected to the outside of the water spray pipe, and the water inlet pipe is connected to an external water supply pump; a blowing pipe is provided on the inner side of the upper part of the inner clamping plate, and the blowing pipe is connected to an external blower through a pipe assembly; a first bidirectional screw module is connected between a pair of inner clamping plates, and the first bidirectional screw module is connected to a vertical displacement mechanism; the winding device, the upper clamping mechanism, the upper lifting mechanism, the lower clamping mechanism, the lower lifting mechanism, the first bidirectional screw module, the vertical displacement mechanism, the external water pump and the external blower are all electrically connected to the controller, and a waste residue box arranged opposite to the membrane body is fixedly connected to the base.

[0007] In the above-mentioned automatic detection device for the tensile strength of the PE protective film, the wrinkles on the surface of the film body are repaired by the cooperation of the water spray pipe, the blowing pipe, the upper clamping mechanism and the lower clamping mechanism.

[0008] As a further improvement of the present application, the blowing pipe is a metal conductive tube and is electrically connected to a connecting wire. A three-way pipe is connected to the outside of the blowing pipe. The upper and lower ends of the three-way pipe are respectively connected to an air intake pipe and a suction pipe. An electromagnetic valve is installed at the connection between the air intake pipe and the suction pipe and the three-way pipe. The solenoid valve is electrically connected to the controller, the air intake pipe is connected to an external blower, and the suction pipe is connected to an external negative pressure vacuum cleaner.

[0009] As a further improvement of the present application, the water spray pipe is a transversely arranged circular tubular structure, the mesh plate is a strip mesh plate with an arc-shaped cross-section, and the outer surface of the mesh plate is completely in contact with the circumferential surface of the water spray pipe.

[0010] As a further improvement of the present application, the winding device includes a winding motor, in which a Hall sensor is provided for accurately controlling the release amount of the film body; an infrared distance sensor is fixedly connected to the lower clamping mechanism toward the upper clamping mechanism for detecting the length of the film body between the upper clamping mechanism and the lower clamping mechanism; a tension sensor connected to the lower clamping mechanism is provided in the lower lifting mechanism, and the tension of the film body is detected by the tension sensor; the Hall sensor, infrared distance sensor and tension sensor are all electrically connected to the controller.

[0011] As a further improvement of the present application, the dust cover is a transparent rectangular cover, a feed trough for the film body to pass through is provided on the top of the dust cover, and a pair of guide rollers are installed in the feed trough.

[0012] As a further improvement of the present application, the upper clamping mechanism and the lower clamping mechanism have the same structure. The upper clamping mechanism includes a pair of outer clamping plates, and clamping pads are fixedly connected to the inner walls on the opposite sides of the outer clamping plates. The outer clamping plates are connected to a second bidirectional screw module.

[0013] As a further improvement of the present application, the clamping pad is a hydrophobic rubber strip with a vertical arc-shaped protrusion on the inner side.

[0014] As a further improvement of the present application, the blowing pipe is a cylindrical tubular structure, and an inclined blowing groove is opened at the lower part of the blowing pipe.

[0015] As a further improvement of the present application, a second infrared distance sensor perpendicular to the membrane body is fixedly connected to the inner clamping plate, the second infrared distance sensor is electrically connected to the controller, and the second infrared distance sensor detects the bending direction of the vertically released membrane body.

[0016] To summarize, the present invention uses a winding device, a water spray pipe and a blowing pipe. Before the test, a uniform water flow sprayed out by the water spray pipe forms a water film on the surface of the vertically released membrane body, and the surface tension of the water film is used to repair the wrinkles on the surface of the membrane body, thereby improving the surface flatness of the membrane body, and the gravity of the water film itself is used to improve the verticality of the membrane body, thereby improving the accuracy of subsequent tensile testing; in addition, after the standing period is completed, the membrane body containing the water film is clamped by the upper clamping mechanism and the lower clamping mechanism, and then the water film is blown away to reduce the recovery of membrane body wrinkles caused by dehydration; in addition, through the mutual cooperation of the upper clamping mechanism, the upper lifting mechanism, the lower clamping mechanism and the lower lifting mechanism, the waste film after the test is pulled, cleaned and re-loaded, thereby realizing automated multiple tensile testing, facilitating multiple data comparisons and improving the accuracy of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the three-dimensional structure of this application;

[0018] Figure 2 The interior of the dust cover in this application;

[0019] Figure 3 for Figure 2 A schematic diagram of a longitudinal cross-sectional structure;

[0020] Figure 4 for Figure 3 A schematic diagram of the enlarged structure at A in the middle;

[0021] Figure 5 This is a schematic diagram of the structure of the leveling device in this application from a bottom view;

[0022] Figure 6 It is a schematic diagram of the explosion structure of the water spray pipe in this application;

[0023] Figure 7 It is a schematic diagram of the cross-sectional structure of the blowing pipe in this application;

[0024] Figure 8 It is a schematic diagram of the exploded structure of the upper clamping mechanism in this application;

[0025] Fig. 9 This is a schematic diagram of the state of the water spray pipe undergoing curvature correction in the present application.

[0026] Description of the numbers in the figure:

[0027] 1. Base; 2. Dust cover; 3. Winding device; 4. Membrane body; 5. Upper clamping mechanism; 6. Upper lifting mechanism; 7. Lower clamping mechanism; 8. Lower lifting mechanism; 9. Leveling device; 10. Vertical displacement mechanism; 11. Waste slag box; 12. Inner clamping plate; 13. Water spray pipe; 14. Mesh plate; 15. Water inlet pipe; 16. Blowing pipe; 1601, inclined blowing slot; 17. Tee pipe; 18. Air inlet pipe; 19. Suction pipe; 20. First bidirectional screw module; 21. Outer clamping plate; 22. Clamping pad; 23. Second bidirectional screw module; 24. Guide roller. DETAILED DESCRIPTION

[0028] The following describes two implementation modes of the present application in detail with reference to the accompanying drawings.

[0029] The first implementation method:

[0030] Figure 1-8 The invention shows an automatic detection device for the tensile strength of a PE protective film, comprising a base 1 and a controller; the base 1 is fixedly connected with a dust cover 2, the upper end of the dust cover 2 is fixedly connected with a winding device 3, and a film body 4 extending into the dust cover 2 is wound on the winding device 3; the dust cover 2 is provided with an upper clamping mechanism 5 and a lower clamping mechanism 7 for clamping the film body 4, the upper clamping mechanism 5 is connected with an upper lifting mechanism 6, the lower clamping mechanism 7 is connected with a lower lifting mechanism 8, and a leveling device 9 for leveling the film body 4 is provided between the upper clamping mechanism 5 and the lower clamping mechanism 7;

[0031] The leveling device 9 includes a pair of inner clamping plates 12 symmetrically arranged on both sides of the membrane body 4, a water spray pipe 13 is fixedly connected to the inner side of the lower part of the inner clamping plate 12, a mesh plate 14 is embedded in the water spray pipe 13 on the side facing the membrane body 4, and a water inlet pipe 15 is connected to the outer side of the water spray pipe 13, and the water inlet pipe 15 is connected to the external water supply pump; a blow pipe 16 is arranged on the inner side of the upper part of the inner clamping plate 12, and the blow pipe 16 is connected to the external blower through a pipeline assembly; a first bidirectional screw module 20 is connected between the pair of inner clamping plates 12, and the first bidirectional screw module 20 is connected to the vertical displacement mechanism 10;

[0032] The winding device 3, the upper clamping mechanism 5, the upper lifting mechanism 6, the lower clamping mechanism 7, the lower lifting mechanism 8, the first bidirectional screw module 20, the vertical displacement mechanism 10, the external water pump and the external blower are all electrically connected to the controller, and a waste residue box 11 arranged opposite to the membrane body 4 is fixedly connected to the base 1.

[0033] Specifically, when performing the tensile test of the membrane body 4, the following steps are included:

[0034] Step 1: The controller starts the winding device 3, and the winding device 3 releases the film body 4, so that the lower end of the film body 4 moves to the bottom of the lower clamping mechanism 7;

[0035] It should be noted that the winding device 3 includes a winding motor, in which a Hall sensor is provided to accurately control the release amount of the film body 4. In addition, an infrared distance sensor facing the upper clamping mechanism 5 is fixedly connected to the lower clamping mechanism 7, so that the length of the film body 4 between the upper clamping mechanism 5 and the lower clamping mechanism 7 can be adjusted by the upper lifting mechanism 6 and the lower lifting mechanism 8. The Hall sensor and the infrared distance sensor are both electrically connected to the controller.

[0036] Step 2: The controller starts the external water pump and the vertical displacement mechanism 10. The external water pump injects water into the water spray pipe 13. The water is evenly sprayed onto the membrane body 4 under the action of the mesh plate 14. At the same time, the vertical displacement mechanism 10 drives a pair of inner clamping plates 12 and a pair of water spray pipes 13 thereon to move up and down, so that a water film is formed on both sides of the membrane body 4, and then it is left to stand.

[0037] Specifically, when water is sprayed on the plastic film, water molecules will adhere to the surface of the plastic film and form a thin water film due to the effect of surface tension. This water film will try to cover as much area of ​​the plastic film as possible while minimizing its surface area. In this process, the water film will apply a uniform pulling force to the plastic film, which helps to eliminate wrinkles and uneven parts on the plastic film. In addition, the water film can also serve as a lubricating layer to reduce the friction between fibers or molecules inside the plastic film, making the plastic film easier to stretch and flatten. When the plastic film is stretched, the water film will help maintain the relative positions of the fibers or molecules and prevent them from re-aggregating to form wrinkles.

[0038] Step 3: When the set static time is reached, the external water pump is turned off, and the upper clamping mechanism 5 and the lower clamping mechanism 7 are started to clamp the membrane body 4. After the clamping is completed, the lower lifting mechanism 8 is started, and the lower lifting mechanism 8 drives the lower clamping mechanism 7 to move downward to pre-tension the membrane body 4;

[0039] Specifically, under the action of the water film, the wrinkles on the surface of the membrane body 4 are flattened. At this time, clamping and pre-tensioning are performed to shape the membrane body 4 to prevent the wrinkles from recovering after the water film is removed.

[0040] It should be noted that a tension sensor connected to the lower clamping mechanism 7 is provided in the lower lifting mechanism 8. The tension sensor is a prior art. The specific selection and installation method can be determined by those skilled in the art according to the description of this application, and will not be described in detail in this application. The membrane body 4 is accurately pre-tensioned by the tension sensor, the lower lifting mechanism 8, and the lower clamping mechanism 7.

[0041] Step 4: Start the external blower and the vertical displacement mechanism 10. The airflow generated by the external blower is injected into the blowing pipe 16. The vertical displacement mechanism 10 drives a pair of blowing pipes 16 located on both sides of the membrane body 4 to move from top to bottom to spray, so as to clean the water film on the surface of the membrane body 4, so that the water droplets fall into the waste slag box 11 for centralized collection.

[0042] Step 5: Perform a tensile test, start the lower lifting mechanism 8, the tensile force sensor and the infrared distance sensor, perform a tensile test, and obtain tensile force data and deformation data;

[0043] Step 6, after the test is completed, clean up the residual membrane body 4, including the following sub-steps:

[0044] In the first sub-step, the lower clamping mechanism 7 is started to release the film body 4, and then the upper lifting mechanism 6 and the winding device are started, and the upper lifting mechanism 6 moves to the lowest end of the stroke while clamping the film body 4;

[0045] In the second sub-step, the lower lifting mechanism 8 is started so that the lower clamping mechanism 7 moves to the bottom of the upper clamping mechanism 5 and re-clamps the membrane body 4;

[0046] In the third sub-step, the lower clamping mechanism 7 pulls the waste film body 4 below the upper clamping mechanism 5, so that the tested film body 4 is broken and separated from the untested film body 4 above the upper clamping mechanism 5;

[0047] In the fourth sub-step, the broken waste film body 4 enters the waste residue box 11 storing water, and then the upper lifting mechanism 6 drives the upper clamping mechanism 5 back to the initial position, and the lower lifting mechanism 8 drives the lower clamping mechanism 7 back to the initial position;

[0048] Step seven, repeat steps one to seven to realize automatic multiple tensile tests, compare multiple test data, and improve test accuracy.

[0049] Compared with the traditional plastic film tensile test device, the present invention uses a winding device 3, a water spray pipe 13 and a blowing pipe 16. Before the test, a uniform water flow sprayed from the water spray pipe 13 forms a water film on the surface of the vertically released membrane body 4, and the surface tension of the water film is used to repair the wrinkles on the surface of the membrane body 4, thereby improving the surface flatness of the membrane body 4, and the gravity of the water film itself is used to improve the verticality of the membrane body 4, thereby improving the accuracy of subsequent tensile testing; in addition, after the static state is completed, the membrane body 4 containing the water film is clamped by the upper clamping mechanism 5 and the lower clamping mechanism 7, and then the water film is blown away to reduce the recovery of wrinkles on the membrane body 4 caused by dehydration; in addition, through the mutual cooperation of the upper clamping mechanism 5, the upper lifting mechanism 6, the lower clamping mechanism 7 and the lower lifting mechanism 8, the waste film after the test is pulled, cleaned and re-loaded, thereby realizing automatic multiple tensile testing, facilitating multiple data comparisons and improving the accuracy of the test.

[0050] See also Figure 1 and Figure 3 The dust cover 2 is a transparent rectangular cover. A feeding trough for the film body 4 to pass through is provided on the top of the dust cover 2. A pair of guide rollers 24 are installed in the feeding trough.

[0051] Specifically, in order to facilitate observation of the stretching test, the guide roller 24 allows the membrane body 4 to be in a vertical drooping state under the action of gravity after entering the dust cover 2 .

[0052] See also Figure 8 The upper clamping mechanism 5 and the lower clamping mechanism 7 have the same structure. The upper clamping mechanism 5 includes a pair of outer clamping plates 21. A clamping pad 22 is fixedly connected to the inner wall of the opposite side of the outer clamping plate 21. The outer clamping plate 21 is connected to a second bidirectional screw module 23.

[0053] It should be noted that the clamping pad 22 is a hydrophobic rubber strip with a vertical arc-shaped convexity on the inner side.

[0054] Specifically, during the clamping process, the vertically arc-shaped protruding hydrophobic rubber strip squeezes the water film on the membrane body 4 to both sides, so that the clamping mechanism has a stable clamping effect on the membrane body 4 with the water film on the surface.

[0055] See also Figure 7 The blowing pipe 16 is a cylindrical tubular structure, and an inclined blowing groove 1601 is opened at the lower part of the blowing pipe 16.

[0056] Specifically, during the spraying operation to remove the water film, the inclined airflow sprayed by the spray pipe 16 has a better effect of removing the water film on the surface of the membrane body 4 .

[0057] See also Figure 7 The blowing pipe 16 is a metal conductive tube and is electrically connected to a wiring line. A three-way pipe 17 is connected to the outside of the blowing pipe 16. The upper and lower ends of the three-way pipe 17 are respectively connected to an air intake pipe 18 and a suction pipe 19. A solenoid valve is installed at the connection between the air intake pipe 18 and the suction pipe 19 and the three-way pipe 17. The solenoid valve is electrically connected to the controller. The air intake pipe 18 is connected to an external blower, and the suction pipe 19 is connected to an external negative pressure vacuum cleaner.

[0058] Specifically, before the water spraying operation, the first bidirectional screw module 20 is started, so that a pair of blowing pipes 16 are attached to the two side surfaces of the membrane body 4, and the external negative pressure vacuum cleaner and the solenoid valve connected to the suction pipe 19 are started to perform negative pressure suction on the dust adsorbed on the surface of the membrane body 4. In order to prevent more dust from sticking, the membrane body 4 is destaticized by the blowing pipe 16 made of metal conductive tube material, which improves the dust removal effect and reduces the curling of the membrane body 4 due to static electricity, so that the water film formed by subsequent water spraying is more uniform, thereby improving the wrinkle repair effect.

[0059] Second implementation method:

[0060] Figure 6 and Fig. 9 An automatic detection device for the tensile strength of a PE protective film is shown. Based on the first embodiment, the water spray pipe 13 is a transversely arranged circular tubular structure, and the mesh plate 14 is a strip mesh plate with an arc-shaped cross-section. The outer surface of the mesh plate 14 is completely in contact with the circumferential surface of the water spray pipe 13.

[0061] Specifically, when the membrane body 4 has a large curvature after being released vertically, the first bidirectional screw module 20 is started, so that a pair of water spray pipes 13 are attached to the two side surfaces of the membrane body 4, and the external water pump connected to the water spray pipe 13 on one side is started. The water flow out of the mesh plate 14 of the water spray pipe 13 on one side flows toward the lower rear side of the water spray pipe 13 under the blocking effect of the membrane body 4 and the guiding effect of the lower arc surface of the circular tube itself (Coanda effect). Under the action of the surface tension of water, the membrane body 4 at this position bends along the lower arc surface of the water spray pipe 13. As the vertical displacement mechanism 10 drives the pair of water spray pipes 13 to move up and down, the membrane body 4 with a larger bending curvature of the pair of water spray pipes 13 is corrected for curvature, that is, local reverse bending is performed at various positions of the membrane body 4 with a large curvature, thereby improving the verticality of the membrane body 4 bent due to winding.

[0062] It should be noted that a second infrared distance sensor is fixedly connected to the inner clamping plate 12 and is vertically facing the membrane body 4. The second infrared distance sensor is electrically connected to the controller. The second infrared distance sensor detects the bending direction of the vertically released membrane body 4, and then when the water spray pipe 13 is corrected, the external water pump connected to the water spray pipe 13 on the side opposite to the bending direction of the membrane body 4 is started.

[0063] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. An automatic detection device for the tensile strength of a PE protective film, characterized in that: The invention comprises a base (1) and a controller; the base (1) is fixedly connected to a dust cover (2); the upper end of the dust cover (2) is fixedly connected to a winding device (3); a membrane body (4) extending into the dust cover (2) is wound on the winding device (3); the dust cover (2) is provided with an upper clamping mechanism (5) and a lower clamping mechanism (7) for clamping the membrane body (4); the upper clamping mechanism (5) is connected to an upper lifting mechanism (6); the lower clamping mechanism (7) is connected to a lower lifting mechanism (8); a leveling device (9) for leveling the membrane body (4) is provided between the upper clamping mechanism (5) and the lower clamping mechanism (7); The leveling device (9) comprises a pair of inner clamping plates (12) symmetrically arranged on both sides of the membrane body (4); a water spray pipe (13) is fixedly connected to the inner side of the lower part of the inner clamping plate (12); a mesh plate (14) is embedded in the water spray pipe (13) on the side facing the membrane body (4); a water inlet pipe (15) is connected to the outer side of the water spray pipe (13); and the water inlet pipe (15) is connected to an external water supply pump; a blow pipe (16) is provided on the inner side of the upper part of the inner clamping plate (12); and the blow pipe (16) is connected to an external blower through a pipeline assembly; a first bidirectional screw module (20) is connected between the pair of inner clamping plates (12); and the first bidirectional screw module (20) is connected to a vertical displacement mechanism (10); The winding device (3), the upper clamping mechanism (5), the upper lifting mechanism (6), the lower clamping mechanism (7), the lower lifting mechanism (8), the first bidirectional screw module (20), the vertical displacement mechanism (10), the external water pump and the external blower are all electrically connected to the controller, and a waste slag box (11) arranged opposite to the membrane body (4) is fixedly connected to the base (1).

2. The automatic detection device for the tensile strength of a PE protective film according to claim 1 is characterized in that: The blowing pipe (16) is a metal conductive pipe and is electrically connected to a connection wire. The outside of the blowing pipe (16) is connected to a three-way pipe (17). The upper and lower ends of the three-way pipe (17) are respectively connected to an air intake pipe (18) and a suction pipe (19). A solenoid valve is installed at the connection point between the air intake pipe (18) and the suction pipe (19) and the three-way pipe (17). The solenoid valve is electrically connected to a controller. The air intake pipe (18) is connected to an external blower, and the suction pipe (19) is connected to an external negative pressure vacuum cleaner.

3. The automatic detection device for the tensile strength of a PE protective film according to claim 2 is characterized in that: The water spray pipe (13) is a transversely arranged circular tubular structure, the mesh plate (14) is a strip mesh plate with an arc-shaped cross section, and the outer surface of the mesh plate (14) is completely in contact with the circumferential surface of the water spray pipe (13).

4. The automatic detection device for the tensile strength of a PE protective film according to claim 3 is characterized in that: The winding device (3) comprises a winding motor, in which a Hall sensor is provided for accurately controlling the release amount of the film body (4); the lower clamping mechanism (7) is fixedly connected with an infrared distance sensor facing the upper clamping mechanism (5) for detecting the length of the film body (4) between the upper clamping mechanism (5) and the lower clamping mechanism (7); the lower lifting mechanism (8) is provided with a tension sensor connected to the lower clamping mechanism (7) for detecting the tension of the film body (4); the Hall sensor, the infrared distance sensor and the tension sensor are all electrically connected to the controller.

5. The automatic detection device for the tensile strength of a PE protective film according to claim 1 is characterized in that: The dust cover (2) is a transparent rectangular cover. A feed trough for the film body (4) to pass through is provided on the top of the dust cover (2). A pair of guide rollers (24) are installed in the feed trough.

6. The automatic detection device for the tensile strength of a PE protective film according to claim 1 is characterized in that: The upper clamping mechanism (5) and the lower clamping mechanism (7) have the same structure. The upper clamping mechanism (5) comprises a pair of outer clamping plates (21). A clamping pad (22) is fixedly connected to the inner wall on the opposite side of the outer clamping plate (21). The outer clamping plate (21) is connected to a second bidirectional screw module (23).

7. The automatic detection device for the tensile strength of a PE protective film according to claim 6, characterized in that: The clamping pad (22) is a hydrophobic rubber strip with a vertical arc-shaped convexity on the inner side.

8. The automatic detection device for the tensile strength of a PE protective film according to claim 1 is characterized in that: The blowing pipe (16) is a cylindrical tubular structure, and an inclined blowing groove (1601) is provided at the lower part of the blowing pipe (16).

9. The automatic detection device for the tensile strength of a PE protective film according to claim 3, characterized in that: A second infrared distance sensor is fixedly connected to the inner clamping plate (12) and is perpendicular to the membrane body (4). The second infrared distance sensor is electrically connected to the controller, and the second infrared distance sensor detects the bending direction of the vertically released membrane body (4).

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