Stretch resistance detection device for plastic packaging bag

Abstract

The invention relates to the technical field of material mechanical property detection, in particular to a plastic packaging bag tensile strength detection device which comprises a shell, the top of the shell is rotationally connected with a top cover, the inner side of the shell is fixedly connected with a protection cover, the inner side of the protection cover is provided with a detection assembly used for detecting tensile strength and friction of a packaging bag, and the detection assembly is provided with a clamping groove. A clamping assembly used for fixing the plastic packaging bag is arranged on the inner side of the detection assembly, and a transmission assembly is arranged on the inner side of the detection assembly. A packaging bag is fixed through the clamping assembly, the clamping assembly is driven by the transmission assembly to move left and right together to achieve tensile detection of the packaging bag, and the transmission assembly drives a rotating ring and an arc-shaped plate to drive two friction wheels and a balancing weight to move at the same time. Friction detection, simulation of bumpy road sections and stretching and friction tests of the packaging bag in different states are achieved while tensile detection of the packaging bag is achieved.

Description

Technical Field

[0001] This invention relates to the field of material mechanical property testing technology, and more specifically, to a device for testing the tensile strength of plastic packaging bags. Background Technology

[0002] Plastic packaging bags are bags made from plastic and used to package various daily necessities. They are widely used in daily life and industrial production. Commonly used plastic packaging bags are mostly made of polyethylene film, which is non-toxic and therefore suitable for food packaging. Another type of film is made of polyvinyl chloride (PVC), which is also non-toxic; therefore, this type of film and the plastic bags made from it are suitable for food packaging.

[0003] Chinese Publication No. CN120275167A discloses a tensile strength testing device for plastic packaging bags, including a processing platform with a storage cabinet inside. Support legs are fixedly connected to the four corners of the bottom of the processing platform, and a tensile strength testing mechanism is installed on the top of the platform. The device securely clamps the plastic bag at its four corners using screws, movable clamps, and fixed clamps. Through the coordinated movement of a motor slide rail, linear motor, movable frame, slide rod, and first slider, the device utilizes a slanted slide groove and a second slider to convert the lateral tension into four-directional tension, performing tensile strength testing on the plastic bag in four directions. This design overcomes the limitations of traditional methods that only perform lateral tensile testing, enabling the acquisition of tensile strength data in different directions for the plastic bag. This allows for a comprehensive evaluation of its tensile performance, providing a more accurate basis for quality assessment and ensuring that plastic bags for different applications can withstand tension in the corresponding directions during actual use, thus improving testing accuracy. Although the aforementioned patent can perform tensile testing on plastic bags in four directions, obtain tensile data of plastic bags in different directions, comprehensively evaluate their tensile performance, and provide a more accurate basis for quality assessment, considering that plastic packaging bags may also be subjected to strong friction during the stretching process when subjected to stretching effects in daily use, in addition to considering the stretching effect of the packaging bag, it is also necessary to test the friction during the stretching process.

[0004] In view of this, we propose a tensile strength testing device for plastic packaging bags. Summary of the Invention

[0005] The purpose of this invention is to provide a tensile strength testing device for plastic packaging bags to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides a tensile strength testing device for plastic packaging bags, comprising a housing, a top cover rotatably connected to the top of the housing, a support column fixedly connected to the bottom of the housing, an inlet on one side of the housing, an outlet on the side of the housing away from the inlet, a protective cover fixedly connected to the inner side of the housing, a testing component for testing the tensile strength and friction of the packaging bag disposed on the inner side of the protective cover, a clamping component for fixing the plastic packaging bag disposed on the inner side of the testing component, and a transmission component disposed on the inner side of the testing component. The detection assembly includes a rotating ring, with a first friction wheel fixedly connected between the two rotating rings. A rotating ring cover is fitted on the outer wall of the rotating ring, and an extension plate is fixedly connected to one side of the rotating ring cover. An arc-shaped plate is slidably connected to the end of the extension plate away from the rotating ring cover, and a second friction wheel is rotatably connected between the two arc-shaped plates.

[0007] As a preferred embodiment of the present invention, a No. 1 motor is fixedly connected to the outer wall of the protective cover, a vibration chamber is provided through the middle of the protective cover, a No. 1 rotating rod is rotatably connected to the inner side of the vibration chamber, the end of the No. 1 rotating rod away from the vibration chamber is fixedly connected to a rotating ring, a counterweight is rotatably connected to the outer wall of the inner part of the rotating rod in the vibration chamber, the counterweight is butterfly-shaped, and multiple conveying wheels are rotatably connected to the bottom inner wall of the protective cover.

[0008] As a preferred embodiment of the present invention, the rotating ring has a plurality of No. 1 protrusions fixedly connected to the outer wall on the side away from the No. 1 rotating rod. The No. 1 protrusions are arranged in a circular array on the rotating ring. Similarly, a No. 2 protrusion is fixedly connected to one side of the arc plate. The No. 2 protrusions are arranged in an array along the arc plate.

[0009] As a preferred embodiment of the present invention, the clamping assembly includes a pad, which is slidably connected to the inner wall of the bottom of the protective cover. Columns are fixedly connected to the top of both ends of the pad, and the columns on both sides are internally hollow. Threaded rods are rotatably connected to the inside of the columns, and a second motor is provided at the top of the threaded rods. The second motor is fixedly connected to the top of the columns, and the threaded rods are fixedly connected to the output end of the second motor.

[0010] As a preferred embodiment of the present invention, the outer walls of the threaded rods on both sides are threadedly connected to clamping plates, the surface of the clamping plates is provided with a first strip hole, the top of the clamping plates is electrically slidably connected to a pneumatic rod, the output end of the pneumatic rod is slidably connected through the first strip hole, and the output end of the pneumatic rod is fixedly connected to a pressure plate.

[0011] As a preferred embodiment of the present invention, the transmission assembly includes a plurality of fixed columns, which are fixedly connected to the inner wall of the protective cover by cross columns. Connecting columns are fixedly connected between the plurality of fixed columns. A second rotating rod is rotatably mounted inside each of the plurality of fixed columns. The second rotating rod is fixedly connected to the output end of the first motor. A sector plate is provided at the end of the second rotating rod away from the first motor, and the second rotating rod is rotatably connected to one side of the sector plate.

[0012] As a preferred embodiment of the present invention, a first gear is fixedly connected to the outer wall of the middle end of the second rotating rod below, a turntable is fixedly connected to one side of the first gear, a second gear is meshed with the top of the first gear, a third rotating rod is fixedly connected to the center position of one side of the second gear, and the third rotating rod is rotatably connected to one side of the connecting column.

[0013] As a preferred embodiment of the present invention, the top of the second gear is meshed with a third gear, the third gear is fixedly connected to the outer wall of the upper second rotating rod, and another turntable is fixedly connected to one side of the third gear.

[0014] As a preferred embodiment of the present invention, the turntable below is rotatably connected to a first connecting rod on the side away from the first gear, and a slider is rotatably connected to the end of the first connecting rod away from the turntable. The upper outer wall of the column is fixedly connected to the side of the slider away from the first connecting rod. A second strip hole is opened on the lower surface of the sector plate, and the slider is slidably connected in the second strip hole. A slide rail is opened on the upper surface of the sector plate, and a sliding plate is slidably connected on the slide rail.

[0015] As a preferred embodiment of the present invention, the sliding plate has a plurality of square protrusions fixedly connected to the side away from the slide rail. The plurality of square protrusions are inclined surfaces with different orientations on the side that are close to each other. The square protrusions are on the same vertical plane as the first protrusion strip and the second protrusion strip. The size of the plurality of square protrusions matches the gap size of the first protrusion strip and the second protrusion strip. The sliding plate is also rotatably connected to a second connecting rod on the side away from the slide rail. The second connecting rod is rotatably connected to the side of the upper turntable away from the third gear on the side away from the sliding plate.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this plastic packaging bag tensile strength testing device, the packaging bag is fixed by the clamping component, and the clamping component is driven to move left and right together by the transmission component to realize the tensile strength testing of the packaging bag. The transmission component simultaneously drives the rotating ring and the arc plate to drive the two friction wheels, so as to realize the friction test while performing the tensile strength test of the packaging bag.

[0017] 2. In this plastic packaging bag tensile strength testing device, the different numbers of gears in the transmission components on both sides are distributed to achieve different movement speeds of the first and second friction wheels on both sides, and at the same time, the counterweight is used to generate vibration, thereby simulating the bumpy road section during the transportation of the packaging bag.

[0018] 3. In this plastic packaging bag tensile strength testing device, the packaging bag is moved up and down by the clamping component and blocked by multiple friction wheels, which causes the packaging bag to bend, thus realizing the tensile and friction tests of the packaging bag under different states.

[0019] 4. In this plastic packaging bag tensile strength testing device, the irregular stretching and relaxation effect of the two columns is created by adjusting the rotation speed of the No. 1 motor on both sides, and the friction force of the No. 1 friction wheel and the No. 2 friction wheel is simulated to better reflect the real situation. Attached Figure Description

[0020] Figure 1 This is a three-dimensional schematic diagram of the tensile strength testing device for plastic packaging bags of the present invention. Figure 2 This is a schematic cross-sectional view of the tensile strength testing device for plastic packaging bags of the present invention. Figure 3 This is a three-dimensional internal view of the tensile strength testing device for plastic packaging bags of the present invention; Figure 4 This is a three-dimensional unfolded schematic diagram of the tensile strength testing device for plastic packaging bags of the present invention; Figure 5 This is a three-dimensional unfolded schematic diagram of the detection components of the plastic packaging bag tensile strength detection device of the present invention; Figure 6 This is a three-dimensional schematic diagram of the clamping assembly of the plastic packaging bag tensile strength testing device of the present invention. Figure 7 This is a three-dimensional schematic diagram of the transmission components of the plastic packaging bag tensile strength testing device of the present invention; Figure 8 This is a three-dimensional schematic diagram showing the details of the transmission components of the tensile strength testing device for plastic packaging bags of the present invention; The meanings of the labels in the diagram are as follows: 1. Outer shell; 11. Top cover; 12. Support column; 13. Inlet; 14. Outlet; 2. Detection assembly; 21. Protective cover; 211. Motor No. 1; 212. Vibration chamber; 213. Counterweight; 214. Conveyor wheel; 22. Rotating rod No. 1; 221. Rotary ring; 222. Raised strip No. 1; 23. Friction wheel No. 1; 24. Rotary ring cover; 241. Extension plate; 25. Arc plate; 251. Raised strip No. 2; 26. Friction wheel No. 2; 3. Clamping assembly; 31. Pad; 311. Column; 312. Threaded rod; 313. Motor No. 2; 32. Clamping plate; 321. No. 1 strip hole; 322. Pneumatic rod; 323. Pressure plate; 4. Transmission assembly; 41. Fixed column; 411. Connecting column; 42. Second rotating rod; 421. First gear; 422. Turntable; 43. Second gear; 431. Third rotating rod; 432. Third gear; 44. First connecting rod; 441. Slider; 45. Sector plate; 451. Second strip hole; 452. Slide rail; 46. Sliding plate; 461. Square protrusion; 462. Second connecting rod. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Example 1 Please see Figures 1-8 As shown, this embodiment provides a tensile strength testing device for plastic packaging bags, including a housing 1. A top cover 11 is rotatably connected to the top of the housing 1, and a support column 12 is fixedly connected to the bottom of the housing 1. An inlet 13 is provided on one side of the housing 1, and an outlet 14 is provided on the side of the housing 1 away from the inlet 13. A protective cover 21 is fixedly connected to the inner side of the housing 1. A testing component 2 for testing the tensile strength and friction of the packaging bag is provided on the inner side of the protective cover 21. A clamping component 3 for fixing the plastic packaging bag is provided on the inner side of the testing component 2. A transmission component 4 is provided on the inner side of the testing component 2. The testing component 2 includes a rotating ring 221. A first friction wheel 23 is fixedly connected between the two rotating rings 221. A rotating ring cover 24 is fitted on the outer wall of the rotating ring 221. An extension plate 241 is fixedly connected to one side of the rotating ring cover 24. An arc plate 25 is slidably connected to the end of the extension plate 241 away from the rotating ring cover 24. A second friction wheel 26 is rotatably connected between the two arc plates 25.

[0024] like Figures 3-6 As shown, a motor 211 is fixedly connected to the outer wall of the protective cover 21. A vibration chamber 212 is provided through the middle of the protective cover 21. A rotating rod 22 is rotatably connected to the inner side of the vibration chamber 212. The end of the rotating rod 22 away from the vibration chamber 212 is fixedly connected to a rotating ring 221. A counterweight 213 is rotatably connected to the outer wall of the inner part of the rotating ring 221. The counterweight 213 is butterfly-shaped. Multiple conveying wheels 214 are rotatably connected to the inner bottom wall of the protective cover 21. Multiple protruding strips 222 are fixedly connected to the outer wall of the rotating ring 221 on the side away from the rotating rod 22. The protruding strips 222 are arranged in a circular array on the rotating ring 221. A second protruding strip 251 is also fixedly connected to one side of the arc plate 25. The second protruding strip 251 is arranged in an array along the arc plate 25.

[0025] Among them, the interior of the two side counterweights 213 is provided with electromagnetic force counterweight balls that roll in the direction of extension of the two side counterweights 213.

[0026] like Figure 6 As shown, the clamping assembly 3 includes a pad 31, which is slidably connected to the inner wall of the bottom of the protective cover 21. Columns 311 are fixedly connected to the top of both ends of the pad 31. The columns 311 on both sides are internally hollow. Threaded rods 312 are rotatably connected inside the columns 311. A second motor 313 is installed at the top of the threaded rods 312. The second motor 313 is fixedly connected to the top of the columns 311. The threaded rods 312 are fixedly connected to the output end of the second motor 313. Clamping plates 32 are threadedly connected to the outer walls of the threaded rods 312 on both sides. A first strip hole 321 is opened on the surface of the clamping plates 32. A pneumatic rod 322 is electrically slidably connected to the top of the clamping plates 32. The output end of the pneumatic rod 322 is slidably connected through the first strip hole 321. A pressure plate 323 is fixedly connected to the output end of the pneumatic rod 322.

[0027] like Figures 7-8As shown, the transmission assembly 4 includes multiple fixed columns 41, which are fixedly connected to the inner wall of the protective cover 21 via horizontal columns. Connecting columns 411 are fixedly connected between the multiple fixed columns 41. A second rotating rod 42 rotatably rotates within each of the multiple fixed columns 41. The second rotating rod 42 is fixedly connected to the output end of the first motor 211. A sector plate 45 is provided at the end of the second rotating rod 42 away from the first motor 211. The second rotating rod 42 is rotatably connected to one side of the sector plate 45. A first gear 421 is fixedly connected to the outer wall of the middle end of the lower second rotating rod 42. A turntable 422 is fixedly connected to one side of gear 421. Gear 43 is meshed with the top of gear 421. A rotating rod 431 is fixedly connected to the center of one side of gear 43. The rotating rod 431 is rotatably connected to one side of connecting post 411. Gear 432 is meshed with the top of gear 43. Gear 432 is fixedly connected to the outer wall of the upper rotating rod 42. Another turntable 422 is fixedly connected to one side of gear 432. The lower turntable 422 is located away from gear 421. A first connecting rod 44 is rotatably connected to one side of the turntable 422. A slider 441 is rotatably connected to the end of the first connecting rod 44 away from the turntable 422. The upper outer wall of the column 311 is fixedly connected to the side of the slider 441 away from the first connecting rod 44. A second strip hole 451 is opened on the lower surface of the sector plate 45. The slider 441 is slidably connected in the second strip hole 451. A slide rail 452 is opened on the upper surface of the sector plate 45. A sliding plate 46 is slidably connected on the slide rail 452. Multiple square protrusions are fixedly connected to the side of the sliding plate 46 away from the slide rail 452. Block 461, multiple square protrusions 461 are inclined planes with different orientations on the side that are close to each other. The square protrusions 461 are on the same vertical plane as the first protrusion strip 222 and the second protrusion strip 251. The size of the multiple square protrusions 461 matches the gap size of the first protrusion strip 222 and the second protrusion strip 251. The sliding plate 46 is also rotatably connected to the second connecting rod 462 on the side away from the slide rail 452. The second connecting rod 462 is rotatably connected to the side of the upper turntable 422 away from the third gear 432 on the side away from the sliding plate 46.

[0028] Among them: such as Figures 6-7 As shown, the transmission assembly 4 located around the rotating ring 221 is driven by the second rotating rod 42 to rotate the first gear 421, the second gear 43, and the third gear 432 together. However, the transmission assembly 4 located on one side of the arc plate 25 is driven by the two first gears 421 on the two second rotating rods 42 meshing with each other. The two are different.

[0029] Furthermore, the circumference of the first gear 421, which is located around the ring 221, is many times that of the second gear 43, and the circumference of the second gear 43 is many times that of the third gear 432. That is, for every rotation of the first gear 421, the third gear 432 rotates a number of times the above multiples.

[0030] Therefore, when it is necessary to perform tensile testing on plastic packaging bags, such as Figures 2-4 As shown, during the preparation stage, after the staff connects the inlet 13 to the conveying outlet of the plastic packaging bag, the entire device is started to inspect the plastic packaging bag. First, the plastic packaging bag is conveyed from the inlet 13 onto the top conveyor wheel 214 of the protective cover 21. Then, the position of the packaging bag is adjusted by the conveyor wheel 214 so that both ends of the packaging bag are on top of the pressure plate 323. Then, the clamping assembly 3 is started. Driven by the second motor 313, the threaded rod 312 rotates, and the threaded rod 312 drives the clamping plate 32 to move up and down. Similarly, the pressure plate 323 can be moved up and down by the pneumatic rod 322 to fix the four corners of the packaging bag between the pressure plate 323 and the clamping plate 32. After the position of the packaging bag is fixed, it is inspected.

[0031] It should be noted that, as Figure 6 As shown, a square groove is provided on the top of the pad 31 for the pressing plate 323 to penetrate deeply. When the pressing plate 323 is driven down to the lowest position, it is fully inserted into the square groove, causing the four corners of the packaging bag to move to the top of the pressing plate 323. A tension sensor is provided inside the clamping plate 32. When the clamping plate 32 moves left and right with the column, the tension sensor senses the intensity and transmits the data to the control console.

[0032] Considering that the friction and tensile forces on the packaging bag fluctuate greatly and are wavy during transportation on bumpy roads, when simulating a bumpy road, the second rotating rod 42 rotates under the drive of the first motor 211. During the rotation of the second rotating rod 42, the first gear 421 rotates as well. At this time, the first gear 421 drives the second gear 43 and the third gear 432 to rotate as well. Simultaneously, the first gear 421 and the third gear 432 also drive the upper and lower turntables 422 to rotate together. During the rotation of the lower turntable 422, a pushing and pulling reciprocating effect is created on the slider 441, causing the slider 441 to slide within the second slot 451, and simultaneously moving the column 311. Figure 8 As shown, when slider 441 is moved to the right, the packaging bag is stretched and tightened; conversely, when slider 441 moves to the left, the packaging bag is relaxed. Meanwhile, as the upper turntable 422 rotates, it drives the second connecting rod 462 to rotate, creating a pushing and pulling reciprocating effect on the sliding plate 46. At this time, multiple square protrusions 461 are inserted between the first protrusion strip 222, and the inclined plane pushes and squeezes the first protrusion strip 222 to make the rotating ring 221 rotate at a fixed angle. The rotation of the rotating ring 221 will also drive the first rotating rod 22 and the first friction wheel 23 to rotate. At this time, the first friction wheel 23 will rub against the surface of the packaging bag during rotation. On the other side, due to the different gear distribution, the arc plate 25 driven by the square protrusions 461 and the second friction wheel 26 rotate at a slower speed than the rotating ring 221 and the first friction wheel 23. After the first friction wheel 23 has been detected for a period of time, the second friction wheel 26 will also gradually rotate to the surface of the packaging bag to generate friction. At the same time, the counterweight 213 in the vibration chamber 212 will generate vibration on the first friction wheel 23 to simulate the transportation of bumpy road sections. It should be noted that under normal conditions, the two counterweight balls and the middle connecting part have a mutual adsorption effect, that is, the counterweight balls are both in the inner position. When the first rotating rod 22 starts to rotate, the upper counterweight ball will generate a repulsive effect and slide upward, while the lower counterweight ball continues to be attracted. At this time, the center of the upper counterweight block 213 changes, and the counterweight block 213 rotates. During the rotation, the counterweight ball continues to be attracted after rotating to the bottom position, while the upper counterweight ball turns into repulsion. At this time, the counterweight blocks 213 rotate continuously with each other, and the counterweight ball vibrates when it hits the counterweight block 213 during the sliding process. This vibration is transmitted to the first friction wheel 23 through the vibration chamber 212, realizing the simulation of the bumpy road section during the transportation of the packaging bag. In addition, during the downward sliding of the transmission arc plate 25 of the transmission component 4, the clamping plate 32, the pneumatic rod 322 and the pressure plate 323 can be driven to move upward together by the second motor 313. At this time, the middle part of the packaging bag is blocked by the first friction wheel 23 and the second friction wheel 26, which will cause the packaging bag to be stretched and rubbed in a bent state. The stretching and friction test of the packaging bag in different states can be achieved by adjusting the second friction wheel 26. In addition, the irregular stretching and relaxation effect of the two columns 311 can also be achieved by adjusting the rotation speed of the No. 1 motor 211 on both sides, and the friction force simulated by the No. 1 friction wheel 23 and the No. 2 friction wheel 26 at the same time is more in line with the real situation.

[0033] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A tensile strength testing device for plastic packaging bags, comprising a housing (1), characterized in that: The top of the outer shell (1) is rotatably connected to a top cover (11), the bottom of the outer shell (1) is fixedly connected to a support column (12), an inlet (13) is opened on one side of the outer shell (1), an outlet (14) is opened on the side of the outer shell (1) away from the inlet (13), a protective cover (21) is fixedly connected to the inner side of the outer shell (1), a detection component (2) for detecting the stretching and friction of the packaging bag is provided on the inner side of the protective cover (21), a clamping component (3) for fixing the plastic packaging bag is provided on the inner side of the detection component (2), and a transmission component (4) is provided on the inner side of the detection component (2). The detection component (2) includes a rotating ring (221), a first friction wheel (23) is fixedly connected between the two rotating rings (221), a rotating ring cover (24) is fitted on the outer wall of the rotating ring (221), an extension plate (241) is fixedly connected to one side of the rotating ring cover (24), an arc plate (25) is slidably connected to the end of the extension plate (241) away from the rotating ring cover (24), and a second friction wheel (26) is rotatably connected between the two arc plates (25).

2. The tensile strength testing device for plastic packaging bags according to claim 1, characterized in that: A motor (211) is fixedly connected to the outer wall of the protective cover (21). A vibration chamber (212) is provided through the middle of the protective cover (21). A rotating rod (22) is rotatably connected to the inner side of the vibration chamber (212). The end of the rotating rod (22) away from the vibration chamber (212) is fixedly connected to the rotating ring (221). A counterweight (213) is rotatably connected to the outer wall of the inner part of the rotating rod (221) of the vibration chamber (212). The counterweight (213) is butterfly-shaped. Multiple conveyor wheels (214) are rotatably connected to the bottom inner wall of the protective cover (21).

3. The tensile strength testing device for plastic packaging bags according to claim 2, characterized in that: The rotating ring (221) has multiple first protrusions (222) fixedly connected to the outer wall on the side away from the first rotating rod (22). The first protrusions (222) are arranged in a circular array on the rotating ring (221). The arc plate (25) also has a second protrusion (251) fixedly connected to one side. The second protrusions (251) are arranged in an array along the arc plate (25).

4. The tensile strength testing device for plastic packaging bags according to claim 3, characterized in that: The clamping assembly (3) includes a pad (31), which is slidably connected to the inner wall of the bottom of the protective cover (21). The top of both ends of the pad (31) are fixedly connected to columns (311). The columns (311) on both sides are hollow inside. The inside of the columns (311) is rotatably connected to a threaded rod (312). The top of the threaded rod (312) is provided with a second motor (313). The second motor (313) is fixedly connected to the top of the column (311). The threaded rod (312) is fixedly connected to the output end of the second motor (313).

5. The tensile strength testing device for plastic packaging bags according to claim 4, characterized in that: The outer walls of the threaded rods (312) on both sides are threaded with clamping plates (32). A first strip hole (321) is opened on the surface of the clamping plate (32). A pneumatic rod (322) is electrically slidably connected to the top of the clamping plate (32). The output end of the pneumatic rod (322) is slidably connected through the first strip hole (321). A pressure plate (323) is fixedly connected to the output end of the pneumatic rod (322).

6. The tensile strength testing device for plastic packaging bags according to claim 5, characterized in that: The transmission assembly (4) includes multiple fixed columns (41), which are fixedly connected to the inner wall of the protective cover (21) by a horizontal column. A connecting column (411) is fixedly connected between the multiple fixed columns (41). A second rotating rod (42) is rotatably mounted inside each of the multiple fixed columns (41). The second rotating rod (42) is fixedly connected to the output end of the first motor (211). A fan-shaped plate (45) is provided at the end of the second rotating rod (42) away from the first motor (211). The second rotating rod (42) is rotatably connected to one side of the fan-shaped plate (45).

7. The tensile strength testing device for plastic packaging bags according to claim 6, characterized in that: A first gear (421) is fixedly connected to the outer wall of the middle end of the second rotating rod (42) below. A turntable (422) is fixedly connected to one side of the first gear (421). A second gear (43) is meshed with the top of the first gear (421). A third rotating rod (431) is fixedly connected to the center of one side of the second gear (43). The third rotating rod (431) is rotatably connected to one side of the connecting column (411).

8. The tensile strength testing device for plastic packaging bags according to claim 7, characterized in that: The top of the second gear (43) is meshed with the third gear (432), which is fixedly connected to the outer wall of the upper second rotating rod (42). Another turntable (422) is fixedly connected to one side of the third gear (432).

9. The tensile strength testing device for plastic packaging bags according to claim 8, characterized in that: The turntable (422) below is rotatably connected to a first connecting rod (44) on the side away from the first gear (421). The first connecting rod (44) is rotatably connected to a slider (441) at the end away from the turntable (422). The upper outer wall of the column (311) is fixedly connected to the side of the slider (441) away from the first connecting rod (44). The lower surface of the fan-shaped plate (45) is provided with a second strip hole (451). The slider (441) is slidably connected in the second strip hole (451). The upper surface of the fan-shaped plate (45) is provided with a slide rail (452). A sliding plate (46) is slidably connected on the slide rail (452).

10. A tensile strength testing device for plastic packaging bags according to claim 9, characterized in that: The sliding plate (46) has a plurality of square protrusions (461) fixedly connected on the side away from the slide rail (452). The plurality of square protrusions (461) are inclined surfaces with different orientations on the side that are close to each other. The square protrusions (461) are on the same vertical plane as the first protrusion strip (222) and the second protrusion strip (251). The size of the plurality of square protrusions (461) matches the gap size of the first protrusion strip (222) and the second protrusion strip (251). The sliding plate (46) is also rotatably connected to the second connecting rod (462) on the side away from the slide rail (452). The second connecting rod (462) is rotatably connected to the side of the upper turntable (422) away from the third gear (432) on the side away from the sliding plate (46).

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