Plastic bag handle tensile strength testing device

Abstract

This utility model relates to the technical field of packaging material testing equipment, and in particular to a device for testing the tensile strength of plastic bag handles. It includes a tensile strength testing machine with a mounting plate connected to its upper and lower ends. A controller is installed on the tensile strength testing machine. A compression plate is slidably connected to the front of the mounting plate, and a limit block is fixedly connected to the rear of the mounting plate. A top block is slidably connected within the limit block, and the top block engages with the compression plate. An adjusting screw is rotatably connected to the front of the mounting plate and threadedly connected to the compression plate. A return spring is sleeved on the rear of the top block. By linking a rangefinder with an auxiliary light, the auxiliary light adjusts the crosshair projection position according to the distance between the upper and lower mounting plates detected by the rangefinder, forming a vertically aligned reference. This ensures that the upper and lower ends of the plastic bag are held in the same vertical direction, achieving vertical clamping of the plastic bag and improving the accuracy of the test data.

Description

Technical Field

[0001] This utility model relates to the technical field of packaging material testing equipment, and in particular to a device for testing the tensile strength of plastic bag handles. Background Technology

[0002] Plastic bags, as a lightweight and economical packaging material, are widely used in retail, logistics, and food packaging. Their handles are the part that consumers directly contact during use, bearing the entire load. However, during production and use, plastic bag handles often break or tear due to factors such as uneven material thickness, defects in the heat-sealing process, or unreasonable structural design. This seriously affects the user experience and may cause safety hazards such as items scattering. Therefore, accurate testing of the tensile strength of plastic bag handles has become a key step in ensuring product quality and optimizing production processes.

[0003] In existing technologies, the tensile strength testing of plastic bag handles mainly relies on general-purpose material testing machines or customized testing equipment. By fixing both ends of the plastic bag handle with clamps, the tensile force in a usage scenario is simulated. The tensile force is applied at a constant speed or in a stepped manner until the handle breaks or deforms significantly, and the maximum tensile force required for failure is recorded. While such equipment can achieve quantitative testing and adjust the clamp position to ensure the handle is in a vertical tensile state, the operator must manually hold the plastic bag during the testing process, making it difficult to guarantee a vertical grip. When consumers carry plastic bags, the force on the handle is usually in the vertical direction.

[0004] Existing testing equipment's clamping method cannot accurately simulate the actual stress state of plastic bag handles. When the handle is not fully vertically fixed due to operator error, the test tensile force will produce a combined horizontal and vertical component, which differs significantly from the actual use condition where the handle mainly bears a single vertical tensile force. This deviation in clamping angle directly leads to distorted test data, making it difficult to accurately assess the tensile performance of the handle in real-world usage scenarios, thus affecting the targeted nature of product quality control and process improvement. Utility Model Content

[0005] To overcome the drawback of clamping misalignment affecting the test data, this utility model provides a device for testing the tensile strength of plastic bag handles, aiming to solve the above-mentioned shortcomings.

[0006] A device for testing the tensile strength of plastic bag handles includes a tensile strength testing machine. The tensile strength testing machine is equipped with a cylinder for stretching the plastic bag. A mounting plate is connected to the lower end of the cylinder. A mounting plate is also connected to the bottom of the tensile strength testing machine. A controller is installed in the tensile strength testing machine. A compression plate is slidably connected to the front side of the mounting plate. A limit block is fixedly connected to the rear side of the mounting plate. A top block is slidably connected inside the limit block. The top block is in compression engagement with the compression plate. An adjusting screw is rotatably connected to the front side of the mounting plate. The adjusting screw is threadedly connected to the compression plate. A return spring is sleeved on the rear side of the top block. One end of the return spring is connected to the top block, and the other end is connected to the limit block. A marking component for assisting in the clamping and alignment of the plastic bag is provided at the bottom of the upper limit block.

[0007] More preferably, the marking component includes a rangefinder, which is mounted on the bottom of the limiting block and wired to the controller. A fixing plate is connected to the rear end of the bottom of the limiting block, and an electric slide rail is mounted on the front side of the fixing plate. An auxiliary light is slidably connected to the front side of the fixing plate, and the electric slide rail is used to drive the auxiliary light to move up and down.

[0008] More preferably, it also includes a drive wheel, a motor is mounted on the side of the mounting plate, the motor is wired to the controller, the drive wheel is rotatably connected to the mounting plate, a driven wheel is rotatably connected to the front end of the top block, the driven wheel is in contact with the drive wheel, and the shaft of the drive wheel is connected to the output shaft of the motor.

[0009] More preferably, the bottom of the limiting block is connected to a protective frame, which encloses the rangefinder.

[0010] More preferably, both the driven wheel and the driving wheel are fitted with rubber rings.

[0011] More preferably, protective pads are connected to both the rear side of the extrusion plate and the front side of the top block, and the protective pads are in contact with the plastic bag.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. By linking the rangefinder with the auxiliary light, the auxiliary light adjusts the crosshair projection position according to the distance between the upper and lower mounting plates detected by the rangefinder, forming a vertically aligned reference. This ensures that the upper and lower ends of the plastic bag are referenced in the same vertical direction when clamping, thereby achieving vertical clamping of the plastic bag and improving the accuracy of the detection data.

[0014] 2. Through the cooperation of the driven wheel, the driving wheel and the motor, the motor drives the driving wheel to rotate. The friction between the rubber ring and the plastic bag is used to automatically feed the plastic bag into the mounting plate, ensuring that the plastic bag remains vertical during the feeding process, thus achieving fast and accurate positioning of the plastic bag. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the installation structure of the electric slide rail and fixing plate of this utility model.

[0017] Figure 3 This is a cross-sectional view showing the connection relationship between the adjusting screw and the extrusion plate of this utility model.

[0018] The components in the attached diagram are labeled as follows: 1. Tensile strength testing machine, 2. Controller, 3. Mounting plate, 4. Extrusion plate, 5. Adjusting screw, 6. Rangefinder, 7. Fixing plate, 8. Electric slide rail, 9. Auxiliary light, 10. Limit block, 11. Top block, 12. Return spring, 13. Driven wheel, 14. Drive wheel, 15. Motor, 16. Protective frame, 17. Rubber ring, 18. Protective pad. Detailed Implementation

[0019] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] Example: A device for testing the tensile strength of plastic bag handles, such as... Figures 1-3As shown, the device includes a tensile strength testing machine 1, a controller 2, a mounting plate 3, a compression plate 4, an adjusting screw 5, a limit block 10, a top block 11, a return spring 12, and a marking assembly. The tensile strength testing machine 1 is equipped with a cylinder for stretching plastic bags. The lower end of the cylinder is connected to the mounting plate 3. The stroke range of the cylinder must cover the maximum stretching length required for testing the plastic bag handle to ensure that plastic bags of different specifications can complete the full stroke test. The bottom of the tensile strength testing machine 1 is also connected to the mounting plate 3. The tensile strength testing machine 1 is equipped with a controller 2, which integrates a tensile sensor data receiving module and can process the data between the rangefinder 6 and the tensile value in real time. The mounting plate 3 has a sliding connection to a compression plate 4 on its front side and a fixed connection to a limit block 10 on its rear side. A top block 11 is slidably connected inside the limit block 10 and is in compression fit with the compression plate 4. An adjusting screw 5 is rotatably connected to the front side of the mounting plate 3 and is threadedly connected to the compression plate 4. The sliding trajectory of the compression plate 4 must be strictly parallel to the guide rail on the front side of the mounting plate 3 to avoid skewing during clamping. A return spring 12 is sleeved on the rear side of the top block 11. One end of the return spring 12 is connected to the top block 11 and the other end is connected to the limit block 10. A marking component for aligning and clamping plastic bags is provided at the bottom of the limit block 10 located at the upper end.

[0021] like Figure 1 and Figure 2 As shown, the marking assembly includes a rangefinder 6, a fixing plate 7, an electric slide rail 8, and an auxiliary light 9. The rangefinder 6 is installed at the bottom of the limit block 10 and is wired to the controller 2. The fixing plate 7 is connected to the rear end of the bottom of the limit block 10. The electric slide rail 8 is installed on the front side of the fixing plate 7, and the auxiliary light 9 is slidably connected to the front side of the fixing plate 7. The electric slide rail 8 is used to drive the auxiliary light 9 to move up and down. The brightness of the cross rays of the auxiliary light 9 must be higher than the ambient light interference to ensure that the alignment reference is clearly visible.

[0022] like Figure 2 and Figure 3 As shown, it also includes a driven wheel 13, a driving wheel 14, and a motor 15. The motor 15 is mounted on the side of the mounting plate 3 and is wired to the controller 2. The driving wheel 14 is rotatably connected to the mounting plate 3. The driven wheel 13 is rotatably connected to the front end of the top block 11. The driven wheel 13 is in contact with the driving wheel 14. The shaft of the driving wheel 14 is connected to the output shaft of the motor 15. The motor 15 drives the driving wheel 14 to cooperate with the driven wheel 13 to realize the automatic feeding and positioning of plastic bags, reduce manual intervention, and improve detection efficiency.

[0023] like Figure 2As shown, it also includes a protective outer frame 16. The bottom of the limiting block 10 is connected to the protective outer frame 16. The protective outer frame 16 covers the rangefinder 6. The depth of the protective outer frame 16 needs to be 3-5mm higher than the thickness of the rangefinder 6. The material is transparent PC plastic, which takes into account both protection and light transmission, to prevent foreign objects from colliding with the rangefinder 6 during the detection process. At the same time, the transparent design does not obstruct the projection of the auxiliary light 9 rays.

[0024] like Figure 2 and Figure 3 As shown, it also includes a rubber ring 17. Both the driven wheel 13 and the driving wheel 14 are fitted with rubber rings 17. The rubber ring 17 is made of high friction coefficient rubber and has anti-slip texture on its surface to ensure stable feeding of the plastic bag and avoid slippage that could lead to positioning deviation.

[0025] like Figure 2 and Figure 3 As shown, it also includes a protective pad 18. The rear side of the extrusion plate 4 and the front side of the top block 11 are both connected to the protective pad 18. The protective pad 18 is in contact with the plastic bag, and the surface is treated with anti-slip texture. The thickness is 2-3mm to enhance the clamping stability and ensure the safety of the test.

[0026] The staff starts the equipment through the controller 2. The cylinder of the tensile strength testing machine 1 moves downward first, driving the upper mounting plate 3 to move down as a whole. At this time, the fixing plate 7 completely covers the longitudinal area where the plastic bag can be clamped. The rangefinder 6 at the bottom of the limit block 10 detects the vertical distance between it and the top surface of the lower mounting plate 3 in real time, and transmits the distance data to the controller 2 to provide parameter basis for the subsequent displacement adjustment of the auxiliary light 9.

[0027] After receiving the ranging data, the controller 2 drives the electric slide rail 8 on the front side of the fixed plate 7 to work, and drives the auxiliary light 9 to move to the highest point. Then the auxiliary light 9 is turned on, and the red cross rays emitted by it are projected forward vertically to form a clear alignment reference. Before the staff places the upper end of the plastic bag between the driven wheel 13 and the driving wheel 14, they need to adjust the position of the plastic bag through the cross rays to ensure that it enters vertically and achieves accurate vertical positioning before the upper end is clamped.

[0028] After the top alignment is completed, the top of the plastic bag passes through the gap between the driven wheel 13 and the driving wheel 14, and emerges from the top of the mounting plate 3. At this time, the controller 2, based on the distance data fed back by the rangefinder 6, drives the auxiliary light 9 to move downward by the same distance via the electric slide rail 8, so that the projection position of the crosshair moves downward synchronously. When the worker passes the bottom of the plastic bag through the gap between the driven wheel 13 and the driving wheel 14, the alignment is performed again based on the adjusted crosshair, ensuring that the bottom clamping position remains vertically consistent with the top. Then, the motor 15 on the side of the mounting plate 3 is started, and the motor 15 drives the driving wheel 14 to rotate. Through the cooperation between the driven wheel 13 and the driving wheel 14, the bottom of the plastic bag is retracted into the lower mounting plate 3, leaving only the handle area exposed between the upper and lower mounting plates 3.

[0029] After the plastic bag is positioned, the motors 15 at both ends start synchronously to pre-stretch the slack portion of the handle. During this process, a small gap is maintained between the driven wheel 13 and the driving wheel 14, and the plastic bag is moved only by the friction of the surface rubber ring 17, avoiding excessive tension in advance that could deform the handle. After pre-stretching until the slack portion is fully extended, the motor 15 is turned off and stretching stops.

[0030] Subsequently, the operator rotates the adjusting screws 5 at both ends. The adjusting screws 5 are threaded onto the extrusion plate 4, pushing the extrusion plate 4 horizontally towards the top block 11. When the protective pad 18 on the rear side of the extrusion plate 4 contacts the protective pad 18 on the front side of the top block 11, the two protective pads 18 together exert initial pressure on the plastic bag handle. As the adjusting screws 5 continue to rotate, the extrusion plate 4 continuously presses against the plastic bag, simultaneously pushing the top block 11 to slide backward within the limit block 10, compressing the return spring 12. After the return spring 12 is fully compressed, the extrusion plate 4 and the top block 11 are tightly fitted to the surface of the plastic bag through the elastic deformation of the protective pads 18, forming a stable clamping state, providing reliable fixation for subsequent tensile testing.

[0031] After clamping, the tensile strength testing machine 1 starts the tensile testing program. The cylinder drives the upper mounting plate 3 to move upward continuously, while the lower mounting plate 3 remains fixed. Gradually increasing vertical tension is applied to the plastic bag handle. The equipment monitors the changes in tension value in real time. When the handle breaks or deforms significantly due to the tension exceeding the limit, the tension value will suddenly drop. At this time, the equipment records the maximum tension value before the breakage, which is the tensile strength test result of the plastic bag handle.

[0032] After the test is completed, the operator uses the controller 2 to reverse the adjusting screw 5, causing the squeezing plate 4 to slide forward and disengage from the top block 11. The return spring 12, under its elastic action, pushes the top block 11 forward within the limit block 10, completely releasing the plastic bag from the protective pad 18 of the squeezing plate 4 and the top block 11. At this point, the driven wheel 13 and the driving wheel 14 re-engage, allowing the operator to directly remove the remaining plastic bag from between the two wheels, completing the entire testing process.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A device for testing the tensile strength of a plastic bag handle, characterized in that, The device includes a tensile strength testing machine (1), which is equipped with a cylinder for stretching plastic bags. A mounting plate (3) is connected to the lower end of the cylinder. A mounting plate (3) is also connected to the bottom of the tensile strength testing machine (1). A controller (2) is installed in the tensile strength testing machine (1). A compression plate (4) is slidably connected to the front side of the mounting plate (3). A limit block (10) is fixedly connected to the rear side of the mounting plate (3). A top block (1) is slidably connected inside the limit block (10). 1) The top block (11) is pressed and fitted with the extrusion plate (4). An adjusting screw (5) is rotatably connected to the front side of the mounting plate (3). The adjusting screw (5) is threadedly connected to the extrusion plate (4). A return spring (12) is sleeved on the rear side of the top block (11). One end of the return spring (12) is connected to the top block (11), and the other end is connected to the limiting block (10). A marking component for aligning and clamping plastic bags is provided at the bottom of the limiting block (10) located at the upper end.

2. The apparatus for testing the tensile strength of a plastic bag handle according to claim 1, wherein The marking component includes a rangefinder (6), which is mounted on the bottom of the limiting block (10). The rangefinder (6) is wired to the controller (2). A fixing plate (7) is connected to the rear end of the bottom of the limiting block (10). An electric slide rail (8) is mounted on the front side of the fixing plate (7). An auxiliary light (9) is slidably connected to the front side of the fixing plate (7). The electric slide rail (8) is used to drive the auxiliary light (9) to move up and down.

3. The apparatus for testing the tensile strength of plastic bag handles according to claim 2, wherein It also includes a drive wheel (14), a motor (15) is mounted on the side of the mounting plate (3), the motor (15) is wired to the controller (2), the drive wheel (14) is rotatably connected to the mounting plate (3), the front end of the top block (11) is rotatably connected to a driven wheel (13), the driven wheel (13) is in contact with the drive wheel (14), and the shaft of the drive wheel (14) is connected to the output shaft of the motor (15).

4. The apparatus for testing the tensile strength of plastic bag handles according to claim 3, wherein The bottom of the limiting block (10) is connected to a protective frame (16), which encloses the rangefinder (6).

5. The apparatus for testing the tensile strength of plastic bag handles according to claim 4, wherein Both the driven wheel (13) and the driving wheel (14) are fitted with rubber rings (17).

6. The apparatus for testing the tensile strength of plastic bag handles according to claim 5, wherein The rear side of the extrusion plate (4) and the front side of the top block (11) are both connected to protective pads (18), and the protective pads (18) are in contact with the plastic bag.

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