Plastic product drawing force testing device with intelligent pressure adjusting function
The test device, which intelligently adjusts the pull-out force and protective mechanism, solves the problems of splashing and impact when plastic parts break, realizes high-precision pull-out force testing of plastic parts, adapts to the mechanical properties at different stages, and improves the safety and accuracy of the test.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing plastic part pull-out force testing equipment lacks effective protection at the moment of fracture, resulting in the fragmentation of the specimen flying and impact vibration, which affects the test accuracy and safety. In addition, the single speed control mode cannot adapt to the mechanical response characteristics of plastic parts at different stages.
The testing device, which employs intelligent pressure regulation, uses components such as an electric telescopic rod, conductive coil, and magnetorheological fluid to adjust the pulling force in stages. Combined with airbag protection and magnetic buffering, it adapts to the mechanical properties of plastic parts at different stages and reduces impact upon fracture.
It improves the accuracy and safety of pull-out force testing, reduces the splashing and impact effects when the specimen breaks, adapts to different stages of mechanical response, and enhances testing efficiency and accuracy.
Smart Images
Figure CN121830259A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials mechanics testing technology, specifically to a plastic product pull-out force testing device with intelligent pressure regulation function. Background Technology
[0002] With the widespread application of plastic products in the automotive, electronics, and home appliance industries, the reliability requirements for their connection structures (such as snap-fit joints, welds, and adhesive surfaces) are increasingly stringent. Pull-out force testing is a crucial method for evaluating the performance of these connection structures. However, existing technologies for conducting such tests using universal testing machines, especially for destructive pull-out tests on plastic parts, suffer from the following prominent problems: Plastic component fracture often occurs instantaneously, exhibiting brittle fracture characteristics. Existing testing equipment generally lacks specific protective mechanisms against this instantaneous fracture. When a specimen suddenly fractures, the elastic strain energy accumulated in the testing machine system (such as the loading frame and drive screw) and tooling is released instantaneously, causing fragments of the fractured specimen to fly at high speed. Furthermore, the violent vibration of the entire device poses a safety hazard and may impact the testing machine itself.
[0003] When testing large plastic components or performing high-strength pull-out tests, the load applied to the lower support platform changes abruptly at the moment the specimen breaks or reaches its yield point, generating a large instantaneous impact force. This impact causes strong vibrations in the lower platform and even the entire fixture foundation. These vibrations are transmitted through the foundation structure to the force sensor, causing significant interference with the force-displacement curve and hindering the accurate interpretation of key characteristic parameters such as the material's yield point and fracture point. Continuous vibrations prolong the test stabilization time, reduce test efficiency, and may interfere with the temperature field uniformity within the environmental chamber during high and low temperature environmental tests. Existing fixtures mostly use rigid connections or are only equipped with simple passive vibration damping elements such as rubber pads, which have minimal buffering effect on high-frequency, high-intensity instantaneous impacts and cannot meet the requirements of high-precision testing.
[0004] The tensile process of plastic materials typically involves multiple stages, including elastic deformation, yielding, strengthening, and fracture. Each stage has different mechanical response characteristics and varying sensitivities to tensile speed. Currently, most universal testing machines have relatively simple speed control modes, either constant speed control or requiring operators to manually switch speeds during testing based on experience. This approach cannot adapt to the actual tensile state of the plastic part. Summary of the Invention
[0005] The purpose of this invention is to provide a plastic product pull-out force testing device with intelligent pressure regulation function to solve the problems raised in the prior art.
[0006] To achieve the above objectives, the present invention provides the following technical solution: The aforementioned plastic product pull-out force testing device with intelligent pressure regulation function includes a test chamber, a testing unit, a pressure regulation unit, a protection unit, and an impact resistance unit. The test chamber is placed on a horizontal table. The testing unit is fixedly installed inside the test chamber. The testing unit is fixedly connected to the pressure regulation unit. The pressure regulation unit has the function of intelligently adjusting the pull-out force of the plastic part at various stages. The pressure regulation unit is fixedly connected to the protection unit, the pressure regulation unit is fixedly connected to the test chamber, the protection unit is fixedly connected to the test chamber, the protection unit is fixedly connected to the testing unit, and the impact resistance unit is fixedly connected to the pressure regulation unit. A controller is provided on the test chamber.
[0007] Furthermore, the testing unit includes an electric telescopic rod, an upper platform, a guide column, a lower platform, an upper clamp, a lower clamp, and a test piece. There are two electric telescopic rods, left and right. The fixed end of the electric telescopic rod is fixedly installed on the bottom surface inside the test chamber. The telescopic end of the electric telescopic rod is fixedly connected to the upper platform. The upper platform is slidably connected to the guide column. The guide column is fixedly connected to the lower platform. The upper clamp is fixedly installed on the lower surface of the upper platform. The lower clamp is fixedly installed on the upper surface of the lower platform. The test piece is located inside the lower clamp. The lower platform is fixedly connected to the test chamber via a connecting rod.
[0008] Furthermore, the pressure regulating unit includes a fixed plate, a connecting plate, a conductive cylinder, a straight column, a conductive coil, an adjusting spring, a fixing block, and a displacement sensor. The fixed plate is fixedly installed on the inner side wall of the test chamber. The connecting plate is fixedly connected to the telescopic end of the left-side electric telescopic rod. A conductive cylinder is provided on the connecting plate, and the conductive cylinder is slidably connected to the straight column. One end of the straight column is fixedly connected to the fixed plate, and the other end of the straight column is fixedly connected to the fixing block. Conductive coils are evenly distributed on the straight column. One end of the adjusting spring is fixedly connected to the upper surface of the connecting plate, and the other end of the adjusting spring is fixedly connected to the fixing block. The fixing block is fixedly installed on the inner side wall of the test chamber. The displacement sensor is fixedly connected to the connecting plate via a connecting rod, and the displacement sensor is slidably connected to the fixed plate.
[0009] Furthermore, the end of the conductive coil closest to the fixed block is the current input terminal.
[0010] Furthermore, the rate of change of the compression of the adjusting spring is the same as the rate of change of the force-displacement of the test piece.
[0011] Furthermore, the protective unit includes a pull rope, a support roller, a support frame, an air box, a push plate, a return spring, and a spring telescopic plate. One end of the pull rope is fixedly connected to the connecting plate, and the other end passes around the support roller and is fixedly connected to the push plate. The support roller is rotatably mounted on the support frame. The support frame is fixedly mounted on the upper surface of the test chamber. The air box is fixedly mounted on the upper surface of the test chamber. The air box is slidably connected to the pull rope. The push plate is slidably mounted inside the air box. The push plate is connected to the air box through the return spring. The air box is connected to the spring telescopic plate through a flexible hose. The spring telescopic plate has a hollow internal structure. The fixed end of the spring telescopic plate is fixedly mounted on the lower surface of the upper platform. An airbag is provided at the telescopic end of the spring telescopic plate.
[0012] Furthermore, the pusher plate divides the gas box into a left chamber and a right chamber, with the left chamber being a vacuum and the right chamber being filled with gas.
[0013] Furthermore, the impact-resistant unit includes an electromagnet, a guide groove, a wedge block, an adjustment plate, and a buffer spring. The electromagnet is electrically connected to the conductive cylinder and is fixedly installed on the bottom surface of the test chamber. The guide groove is located on the bottom surface of the test chamber, and the wedge block is slidably installed in the guide groove. The lower surface of the adjustment plate is provided with a wedge-shaped surface, and the wedge-shaped surface of the adjustment plate abuts against the inclined surface of the wedge block. One end of the buffer spring is fixedly connected to the upper surface of the adjustment plate, and the other end is fixedly connected to the lower surface of the lower platform.
[0014] Furthermore, the impact-resistant unit also includes a container, a pull rod, a bar magnet, an adjusting spring, an induction coil, and a fixed cylinder. There are two wedge blocks, both of which are slidably connected to the container via push rods. The ends of the two push rods located inside the container abut against each other. The container is fixedly connected to the test chamber. The container is filled with magnetorheological fluid. One end of the pull rod is fixedly connected to the wedge block, and the other end of the pull rod is fixedly connected to the bar magnet. The bar magnet is located inside the fixed cylinder and is connected to the test chamber via an adjusting spring. The induction coil is fixedly installed inside the fixed cylinder, and the fixed cylinder is fixedly connected to the test chamber.
[0015] Furthermore, a magnet is provided at the end of the wedge block near the electromagnet.
[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a controller to apply current to an electric telescopic rod that rises at a constant speed, causing the connecting plate and slide cylinder to move upwards along a straight column, compressing the adjusting spring. A displacement sensor detects the change in the spring compression and transmits a signal to the controller. By monitoring the rate of change of the spring compression, when the spring compression is consistent, the test piece is considered to be in the elastic stage, and the electric telescopic rod continues to pull the test piece at a constant speed. When the spring compression decreases and increases at a slower rate, the test piece enters the yielding stage, and the controller reduces the current to push the electric telescopic rod at a low speed. When the spring compression increases rapidly, the test piece is in the strengthening stage, and the controller controls the electric telescopic rod to push at a medium speed. When the rate of increase of the spring compression drops sharply, the test piece is about to break, and the controller controls the electric telescopic rod to push at an ultra-low speed. By using staged intelligent pressure adjustment to adapt to the pull-out force test, the accuracy of the results is improved.
[0017] 2. In this invention, when the connecting plate moves upward, the reset spring pulls the push plate and the pull rope to the right, compressing the gas in the right chamber of the air chamber and conveying it to the spring telescopic plate, causing the airbag to inflate. When the test piece breaks and splashes, the splashing material impacts the airbag, reducing its kinetic energy and preventing damage to the test device. After the test, the connecting plate moves downward with the electric telescopic rod, and the pull rope moves the push plate to the left. The pressure difference, combined with the restoring force of the spring telescopic plate, recovers the gas in the airbag into the right chamber, preparing for the next protection.
[0018] 3. In this invention, when the connecting plate moves closer to the fixed block, the effective number of turns of the conductive coil increases, the effective resistance of the circuit decreases, the current received by the electromagnet increases, the magnetism of the electromagnet becomes stronger, attracting the wedge block closer, and the wedge block pushes up the adjustment plate to compress the buffer spring, reducing the strong impact force on the platform after the test piece breaks, thus avoiding affecting the accuracy of the test.
[0019] 4. This invention tests the impact force generated by the fracture of plastics with different hardnesses. The instantaneous velocity generated by the wedge-shaped block driving the bar magnet induces different magnitudes of current in the induction coil. A controller then applies different magnetic fields to the magnetorheological fluid, causing variations in its viscosity to resist the movement of the wedge-shaped block and achieving an adaptive impact-resistant effect. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the overall appearance and structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the test chamber of the present invention; Figure 3 This is a schematic diagram of the external structure of some test units of the present invention; Figure 4 for Figure 3 A schematic diagram of the structure from another perspective after removing the guide pillars; Figure 5 This is a schematic diagram of the external structure of the clamp of the present invention; Figure 6This is a schematic diagram of the installation position of the test piece and the lower fixture in this invention; Figure 7 This is a schematic diagram of the protective unit structure of the present invention; Figure 8 for Figure 7 A partial enlarged view of the structure at point A in the middle; Figure 9 This is a schematic diagram of part of the impact-resistant unit structure of the present invention; Figure 10 for Figure 9 A partial enlarged view of the structure at point B in the middle; Figure 11 This is a schematic diagram of the internal structure of the container of the present invention.
[0021] In the diagram: 1. Test chamber; 2. Test unit; 21. Electric telescopic rod; 22. Upper platform; 23. Guide column; 24. Lower platform; 25. Upper clamp; 26. Lower clamp; 27. Test piece; 3. Pressure adjustment unit; 31. Fixing plate; 32. Connecting plate; 33. Conductive cylinder; 34. Straight column; 35. Conductive coil; 36. Adjusting spring; 37. Fixing block; 38. Displacement sensor; 4. Protection unit; 41. Pull rope; 42. Support roller; 43. Support frame; 44. Air box; 45. Push plate; 46. Reset spring; 47. Spring telescopic plate; 5. Impact-resistant unit; 51. Electromagnet; 52. Guide groove; 53. Wedge block; 54. Adjusting plate; 55. Buffer spring; 56. Container box; 57. Pull rod; 58. Bar magnet; 59. Adjusting spring; 510. Induction coil; 511. Fixing cylinder. Detailed Implementation
[0022] The technical solutions of 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.
[0023] Example: Figures 1-11 As shown, the present invention provides a technical solution: like Figure 1As shown, a plastic product pull-out force testing device with intelligent pressure regulation function includes a test chamber 1, a testing unit 2, a pressure regulation unit 3, a protection unit 4, and an impact resistance unit 5. The test chamber 1 is placed on a horizontal table. The testing unit 2 is fixedly installed inside the test chamber 1 and is fixedly connected to the pressure regulation unit 3. The pressure regulation unit 3 has the function of intelligently adjusting the pull-out force of the plastic part at each stage. The pressure regulation unit 3 is fixedly connected to the protection unit 4, the test chamber 1, the protection unit 4, and the testing unit 2. The impact resistance unit 5 is fixedly connected to the test chamber 1, the testing unit 2, and is electrically connected to the pressure regulation unit 3. A controller is provided on the test chamber 1.
[0024] Test chamber 1 is used for the installation and fixation of test unit 2, pressure adjustment unit 3, protection unit 4 and impact resistance unit 5. Test unit 2 is used for pull-out force testing of plastic parts. Pressure adjustment unit 3 is used to adjust the pull-out force of plastic parts. Protection unit 4 is used to protect against splashing when plastic parts break, avoiding damage to the test equipment. Impact resistance unit 5 is used to reduce the impact generated when plastic parts break, avoiding the impact affecting the accuracy of the test. During the pull-out test of plastic parts through test unit 2, pressure adjustment unit 3 intelligently adjusts the pull-out force of plastic parts at each stage, protection unit 4 protects against the breakage of plastic parts, and impact resistance unit 5 weakens the impact generated when plastic parts break, avoiding affecting the accuracy of the test.
[0025] like Figures 2-6 , Figure 8 As shown, test unit 2 includes an electric telescopic rod 21, an upper platform 22, a guide column 23, a lower platform 24, an upper clamp 25, a lower clamp 26, and a test piece 27. There are two electric telescopic rods 21, left and right. The fixed end of the electric telescopic rod 21 is fixedly installed on the bottom surface inside the test chamber 1. The telescopic end of the electric telescopic rod 21 is fixedly connected to the upper platform 22. The upper platform 22 is slidably connected to the guide column 23. The guide column 23 is fixedly connected to the lower platform 24. The upper clamp 25 is fixedly installed on the lower surface of the upper platform 22. The lower clamp 26 is fixedly installed on the upper surface of the lower platform 24. The test piece 27 is located inside the lower clamp 26. The lower platform 24 is fixedly connected to the test chamber 1 through a connecting rod.
[0026] After the staff places the test piece 27 in the lower clamp 26 and fixes it, they fix the upper clamp 25 to the test piece 27. At this time, the controller controls the electric telescopic rod 21 to start, which drives the upper platform 22 to move upward along the guide post 23, thereby driving the upper clamp 25 to move upward, so that the upper clamp 25 can perform a pull-out force test on the test piece 27.
[0027] like Figure 8As shown, the pressure regulating unit 3 includes a fixed plate 31, a connecting plate 32, a conductive cylinder 33, a straight column 34, a conductive coil 35, an adjusting spring 36, a fixing block 37, and a displacement sensor 38. The fixed plate 31 is fixedly installed on the inner wall of the test chamber 1. The connecting plate 32 is fixedly connected to the telescopic end of the left electric telescopic rod 21. The conductive cylinder 33 is provided on the connecting plate 32 and is slidably connected to the straight column 34. One end of the straight column 34 is fixedly connected to the fixed plate 31, and the other end of the straight column 34 is fixedly connected to the fixing block 37. The conductive coil 35 is evenly arranged on the straight column 34. One end of the adjusting spring 36 is fixedly connected to the upper surface of the connecting plate 32, and the other end of the adjusting spring 36 is fixedly connected to the fixing block 37. The fixing block 37 is fixedly installed on the inner wall of the test chamber 1. The displacement sensor 38 is fixedly connected to the connecting plate 32 through a connecting rod and is slidably connected to the fixed plate 31.
[0028] like Figure 8 As shown, the end of the conductive coil 35 closest to the fixed block 37 is the current input terminal.
[0029] The controller supplies a certain current to the electric telescopic rod 21, causing it to rise at a relatively fast and uniform speed. This drives the connecting plate 32 and the sliding cylinder to move synchronously upwards along the straight column 34, thereby compressing the adjusting spring 36. Simultaneously, the displacement sensor 38 detects the change in the compression of the adjusting spring 36 and sends the signal to the controller for processing and monitoring of the rate of change of compression. When the displacement change remains constant, it is determined that the test piece 27 is in the elastic stage. The electric telescopic rod 21 maintains its current speed and pushes the upper platform 22 upwards to pull the test piece 27. As the electric telescopic rod 21 continues to move upwards, when the displacement sensor 38 detects a decrease in the rate of increase in the compression of the adjusting spring 36, the rate of change of compression of the adjusting spring 36 decreases, and the test piece 27 is in the yielding stage. The controller then reduces the current supplied to the electric telescopic rod 21, causing it to push upwards at a low speed, thus deforming the test piece 27. Sufficient time is allowed to prevent the tensile force from fluctuating with the resistance and affecting the test results. During the continued pulling of the test piece 27, when the displacement sensor 38 detects an accelerated increase in the compression of the adjusting spring 36, the rate of change of compression of the adjusting spring 36 increases. At this time, the test piece 27 is in the strengthening stage. The controller controls the electric telescopic rod 21 to continuously push the upper platform 22 at a medium speed to match the gradually increasing deformation resistance and avoid excessive accumulation of tensile force due to excessively slow speed. Finally, when the displacement sensor 38 detects a sudden drop in the rate of increase of compression of the adjusting spring 36, the rate of change of compression of the adjusting spring 36 is at its minimum. At this time, the test piece 27 is in the stage of imminent breakage. The controller controls the electric telescopic rod 21 to slowly push the upper platform 22 at an ultra-low speed to pull the test piece 27 to test the pull-out force. Thus, through staged intelligent pressure adjustment, it adapts to the pull-out force test of the test piece 27 at different stages, thereby improving the accuracy of the test results.
[0030] like Figure 8 As shown, the rate of change of compression of the adjusting spring 36 is the same as the rate of change of force-displacement of the test piece 27.
[0031] By measuring the rate of change of compression of the adjusting spring 36, the electric telescopic rod 21 is modified at different extension speeds, thereby adjusting the pressure to adapt to the pull-out force test of the test piece 27 at different stages and improve the test accuracy.
[0032] like Figure 3 , Figure 7 , Figure 8 As shown, the protective unit 4 includes a pull rope 41, a support roller 42, a support frame 43, an air box 44, a push plate 45, a return spring 46, and a spring telescopic plate 47. One end of the pull rope 41 is fixedly connected to the connecting plate 32, and the other end passes around the support roller 42 and is fixedly connected to the push plate 45. The support roller 42 is rotatably mounted on the support frame 43, which is fixedly mounted on the upper surface of the test chamber 1. The air box 44 is fixedly mounted on the upper surface of the test chamber 1 and is slidably connected to the pull rope 41. The push plate 45 is slidably mounted inside the air box 44 and is connected to the air box 44 through the return spring 46. The air box 44 is connected to the spring telescopic plate 47 through a hose. The spring telescopic plate 47 has a hollow internal structure. The fixed end of the spring telescopic plate 47 is fixedly mounted on the lower surface of the upper platform 22, and an airbag is provided at the telescopic end of the spring telescopic plate 47.
[0033] like Figure 7 As shown, the pusher plate 45 divides the gas box 44 into a left chamber and a right chamber. The left chamber is a vacuum, while the right chamber is filled with gas.
[0034] During the upward movement of the connecting plate 32, the return spring 46, under its own restoring force, pulls the push plate 45 and the pull rope 41 to the right, compressing the gas in the right chamber of the air box 44 and delivering it into the spring telescopic plate 47, thereby causing the airbag to inflate. When the test piece 27 breaks and splashes, the splash impacts the airbag, thereby reducing the kinetic energy of the splash and preventing damage to the test device. After the test, the connecting plate 32 moves downward with the telescopic end of the electric telescopic rod 21, thereby pulling the pull rope 41 to slide around the support roller 42 and pulling the push plate 45 to the left. At this time, under the action of the pressure difference and the action of the spring telescopic plate 47's own restoring force, the gas in the airbag is injected back into the right chamber, thus preparing for the next protection.
[0035] like Figure 2As shown, the impact-resistant unit 5 includes an electromagnet 51, a guide groove 52, a wedge block 53, an adjusting plate 54, and a buffer spring 55. The electromagnet 51 is electrically connected to the conductive cylinder 33. The electromagnet 51 is fixedly installed on the bottom surface of the test chamber 1. The guide groove 52 is set on the bottom surface of the test chamber 1. The wedge block 53 is slidably installed in the guide groove 52. The lower surface of the adjusting plate 54 is provided with a wedge-shaped surface. The wedge-shaped surface of the adjusting plate 54 abuts against the inclined surface of the wedge block 53. One end of the buffer spring 55 is fixedly connected to the upper surface of the adjusting plate 54, and the other end is fixedly connected to the lower surface of the lower platform 24.
[0036] like Figures 9-11 As shown, the impact-resistant unit 5 also includes a container 56, a pull rod 57, a bar magnet 58, an adjusting spring 59, an induction coil 510, and a fixed cylinder 511. There are two wedge blocks 53, both of which are slidably connected to the container 56 via push rods. The ends of the two push rods located inside the container 56 abut against each other. The container 56 is fixedly connected to the test chamber 1. The container 56 is filled with magnetorheological fluid. One end of the pull rod 57 is fixedly connected to the wedge block 53, and the other end of the pull rod 57 is fixedly connected to the bar magnet 58. The bar magnet 58 is located inside the fixed cylinder 511 and is connected to the test chamber 1 via the adjusting spring 59. The induction coil 510 is fixedly installed inside the fixed cylinder 511, and the fixed cylinder 511 is fixedly connected to the test chamber 1.
[0037] like Figure 2 As shown, a magnet is provided at one end of the wedge block 53 near the electromagnet 51.
[0038] As the connecting plate 32 moves upward, its effective number of turns gradually increases as it approaches the fixed block 37, causing the effective resistance of the circuit to gradually decrease. This results in a gradual increase in the current supplied by the conductive coil 35 to the electromagnet 51 via the conductive cylinder 33, which strengthens the magnetism of the electromagnet 51. Consequently, the wedge block 53 is attracted closer to the electromagnet 51. Simultaneously, the wedge block 53 pushes the adjusting plate 54 upward, compressing the buffer spring 55. This generates a strong downward impact force on the lower platform 24 after the test piece 27 breaks. To significantly reduce the impact of large vibrations on the lower platform 24 on test accuracy, as the wedge-shaped block 53 and electromagnet 51 approach, the pull rod 57 moves the bar magnet 58 within the fixed cylinder 511, compressing the adjusting spring 59. During this movement, the magnetic flux of the bar magnet 58 changes, inducing a current in the induction coil 510. Upon detecting this current, the controller introduces a magnetic field into the magnetorheological fluid in the container 56, altering its viscosity. Under the action of the push rod, this further resists the wedge-shaped block. The movement of block 53 due to impact achieves the impact-resistant effect. Furthermore, due to the different hardness of the tested plastic materials, when testing the fracture of soft plastic, the impact generated during fracture is small, the movement speed of wedge block 53 is slow, resulting in a smaller current generated in induction coil 510. Consequently, the magnetic field applied by the controller to the magnetorheological fluid is smaller, achieving impact resistance. When testing the fracture of hard plastic, the impact generated during fracture is large, the movement speed of wedge block 53 is fast, resulting in a larger current generated in induction coil 510. Consequently, the magnetic field applied by the controller to the magnetorheological fluid is larger, achieving impact resistance. Therefore, by testing the impact force generated by the fracture of plastics with different hardness, the instantaneous speed generated by the wedge block 53 driving the bar magnet 58 can generate different induced currents in induction coil 510. The controller then applies different magnetic fields to the magnetorheological fluid, causing different changes in its viscosity to resist the movement of wedge block 53, achieving an adaptive impact-resistant effect. In the early stages of testing, buffer spring 55 eliminates external disturbances to avoid affecting the test results.
[0039] Working principle of the invention: After the staff places the test piece 27 in the lower clamp 26 and fixes it, they fix the upper clamp 25 to the test piece 27. At this time, the controller controls the electric telescopic rod 21 to start, which drives the upper platform 22 to move upward along the guide post 23, thereby driving the upper clamp 25 to move upward, so that the upper clamp 25 can perform a pull-out force test on the test piece 27.
[0040] The controller supplies a certain current to the electric telescopic rod 21, causing it to rise at a relatively fast and uniform speed. This drives the connecting plate 32 and the sliding cylinder to move synchronously upwards along the straight column 34, thereby compressing the adjusting spring 36. Simultaneously, the displacement sensor 38 detects the change in the compression of the adjusting spring 36 and sends the signal to the controller for processing and monitoring of the rate of change of compression. When the displacement change remains constant, it is determined that the test piece 27 is in the elastic stage. The electric telescopic rod 21 maintains its current speed and pushes the upper platform 22 upwards to pull the test piece 27. As the electric telescopic rod 21 continues to move upwards, when the displacement sensor 38 detects a decrease in the rate of increase in the compression of the adjusting spring 36, the rate of change of compression of the adjusting spring 36 decreases, and the test piece 27 is in the yielding stage. The controller then reduces the current supplied to the electric telescopic rod 21, causing it to push upwards at a low speed, thus deforming the test piece 27. Sufficient time is allowed to prevent the tensile force from fluctuating with the resistance and affecting the test results. During the continued pulling of the test piece 27, when the displacement sensor 38 detects an accelerated increase in the compression of the adjusting spring 36, the rate of change of compression of the adjusting spring 36 increases. At this time, the test piece 27 is in the strengthening stage. The controller controls the electric telescopic rod 21 to continuously push the upper platform 22 at a medium speed to match the gradually increasing deformation resistance and avoid excessive accumulation of tensile force due to excessively slow speed. Finally, when the displacement sensor 38 detects a sudden drop in the rate of increase of compression of the adjusting spring 36, the rate of change of compression of the adjusting spring 36 is at its minimum. At this time, the test piece 27 is in the stage of imminent breakage. The controller controls the electric telescopic rod 21 to slowly push the upper platform 22 at an ultra-low speed to pull the test piece 27 to test the pull-out force. Thus, through staged intelligent pressure adjustment, it adapts to the pull-out force test of the test piece 27 at different stages, thereby improving the accuracy of the test results.
[0041] During the upward movement of the connecting plate 32, the return spring 46, under its own restoring force, pulls the push plate 45 and the pull rope 41 to the right, compressing the gas in the right chamber of the air box 44 and delivering it into the spring telescopic plate 47, thereby causing the airbag to inflate. When the test piece 27 breaks and splashes, the splash impacts the airbag, thereby reducing the kinetic energy of the splash and preventing damage to the test device. After the test, the connecting plate 32 moves downward with the telescopic end of the electric telescopic rod 21, thereby pulling the pull rope 41 to slide around the support roller 42 and pulling the push plate 45 to the left. At this time, under the action of the pressure difference and the action of the spring telescopic plate 47's own restoring force, the gas in the airbag is injected back into the right chamber, thus preparing for the next protection.
[0042] As the connecting plate 32 moves upward, its effective number of turns gradually increases as it approaches the fixed block 37, causing the effective resistance of the circuit to gradually decrease. This results in a gradual increase in the current supplied by the conductive coil 35 to the electromagnet 51 via the conductive cylinder 33, which strengthens the magnetism of the electromagnet 51. Consequently, the wedge block 53 is attracted closer to the electromagnet 51. Simultaneously, the wedge block 53 pushes the adjusting plate 54 upward, compressing the buffer spring 55. This generates a strong downward impact force on the lower platform 24 after the test piece 27 breaks. To significantly reduce the impact of large vibrations on the lower platform 24 on test accuracy, as the wedge-shaped block 53 and electromagnet 51 approach, the pull rod 57 moves the bar magnet 58 within the fixed cylinder 511, compressing the adjusting spring 59. During this movement, the magnetic flux of the bar magnet 58 changes, inducing a current in the induction coil 510. Upon detecting this current, the controller introduces a magnetic field into the magnetorheological fluid in the container 56, altering its viscosity. Under the action of the push rod, this further resists the wedge-shaped block. The movement of block 53 due to impact achieves the impact-resistant effect. Furthermore, due to the different hardness of the tested plastic materials, when testing the fracture of soft plastic, the impact generated during fracture is small, the movement speed of wedge block 53 is slow, resulting in a smaller current generated in induction coil 510. Consequently, the magnetic field applied by the controller to the magnetorheological fluid is smaller, achieving impact resistance. When testing the fracture of hard plastic, the impact generated during fracture is large, the movement speed of wedge block 53 is fast, resulting in a larger current generated in induction coil 510. Consequently, the magnetic field applied by the controller to the magnetorheological fluid is larger, achieving impact resistance. Therefore, by testing the impact force generated by the fracture of plastics with different hardness, the instantaneous speed generated by the wedge block 53 driving the bar magnet 58 can generate different induced currents in induction coil 510. The controller then applies different magnetic fields to the magnetorheological fluid, causing different changes in its viscosity to resist the movement of wedge block 53, achieving an adaptive impact-resistant effect. In the early stages of testing, buffer spring 55 eliminates external disturbances to avoid affecting the test results.
[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
Claims
1. A plastic product pull-out force testing device with intelligent pressure regulation function, characterized in that: The aforementioned plastic product pull-out force testing device with intelligent pressure regulation function includes a test chamber (1), a testing unit (2), a pressure regulation unit (3), a protection unit (4), and an impact resistance unit (5). The test chamber (1) is placed on a horizontal table. The testing unit (2) is fixedly installed inside the test chamber (1). The testing unit (2) is fixedly connected to the pressure regulation unit (3). The pressure regulation unit (3) has the function of intelligently adjusting the pull-out force of the plastic part at each stage. The pressure regulation unit (3) is fixedly connected to the protection unit (4). The pressure regulation unit (3) is fixedly connected to the test chamber (1). The protection unit (4) is fixedly connected to the test chamber (1). The protection unit (4) is fixedly connected to the testing unit (2). The impact resistance unit (5) is fixedly connected to the test chamber (1). The impact resistance unit (5) is fixedly connected to the testing unit (2). The impact resistance unit (5) is electrically connected to the pressure regulation unit (3). A controller is provided on the test chamber (1).
2. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 1, characterized in that: The test unit (2) includes an electric telescopic rod (21), an upper platform (22), a guide column (23), a lower platform (24), an upper clamp (25), a lower clamp (26), and a test piece (27). The electric telescopic rod (21) has two parts, left and right. The fixed end of the electric telescopic rod (21) is fixedly installed on the bottom surface inside the test chamber (1). The telescopic end of the electric telescopic rod (21) is fixedly connected to the upper platform (22). The upper platform (22) is slidably connected to the guide column (23). The guide column (23) is fixedly connected to the lower platform (24). The upper clamp (25) is fixedly installed on the lower surface of the upper platform (22). The lower clamp (26) is fixedly installed on the upper surface of the lower platform (24). The test piece (27) is located inside the lower clamp (26). The lower platform (24) is fixedly connected to the test chamber (1) through a connecting rod.
3. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 2, characterized in that: The pressure regulating unit (3) includes a fixed plate (31), a connecting plate (32), a conductive cylinder (33), a straight column (34), a conductive coil (35), an adjusting spring (36), a fixing block (37), and a displacement sensor (38). The fixed plate (31) is fixedly installed on the inner side wall of the test chamber (1). The connecting plate (32) is fixedly connected to the telescopic end of the left electric telescopic rod (21). The conductive cylinder (33) is provided on the connecting plate (32). The conductive cylinder (33) is slidably connected to the straight column (34). One end of the straight column (34) is connected to the fixed plate (38). The plate (31) is fixedly connected, and the other end of the straight column (34) is fixedly connected to the fixing block (37). Conductive coils (35) are evenly arranged on the straight column (34). One end of the adjusting spring (36) is fixedly connected to the upper surface of the connecting plate (32), and the other end of the adjusting spring (36) is fixedly connected to the fixing block (37). The fixing block (37) is fixedly installed on the inner side wall of the test chamber (1). The displacement sensor (38) is fixedly connected to the connecting plate (32) through the connecting rod. The displacement sensor (38) is slidably connected to the fixing plate (31).
4. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 3, characterized in that: The end of the conductive coil (35) closest to the fixed block (37) is the current input terminal.
5. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 4, characterized in that: The rate of change of compression of the adjusting spring (36) is the same as the rate of change of force-displacement of the test piece (27).
6. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 3, characterized in that: The protective unit (4) includes a pull rope (41), a support roller (42), a support frame (43), an air box (44), a push plate (45), a return spring (46), and a spring telescopic plate (47). One end of the pull rope (41) is fixedly connected to the connecting plate (32), and the other end passes around the support roller (42) and is fixedly connected to the push plate (45). The support roller (42) is rotatably mounted on the support frame (43). The support frame (43) is fixedly mounted on the upper surface of the test chamber (1). The air box (44) is fixedly mounted on the upper surface of the test chamber (1). On the upper surface of the test chamber (1), the air box (44) is slidably connected to the pull rope (41), the push plate (45) is slidably installed inside the air box (44), the push plate (45) is connected to the air box (44) through the reset spring (46), the air box (44) is connected to the spring telescopic plate (47) through the hose, the spring telescopic plate (47) has a hollow structure inside, the fixed end of the spring telescopic plate (47) is fixedly installed on the lower surface of the upper platform (22), and an airbag is provided at the telescopic end of the spring telescopic plate (47).
7. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 6, characterized in that: The pusher plate (45) divides the gas box (44) into a left chamber and a right chamber. The left chamber is a vacuum, and the right chamber is filled with gas.
8. The plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 3, characterized in that: The impact-resistant unit (5) includes an electromagnet (51), a guide groove (52), a wedge block (53), an adjustment plate (54), and a buffer spring (55). The electromagnet (51) is electrically connected to the conductive cylinder (33). The electromagnet (51) is fixedly installed on the bottom surface of the test chamber (1). The guide groove (52) is set on the bottom surface of the test chamber (1). The wedge block (53) is slidably installed in the guide groove (52). The lower surface of the adjustment plate (54) is provided with a wedge-shaped surface. The wedge-shaped surface of the adjustment plate (54) abuts against the inclined surface of the wedge block (53). One end of the buffer spring (55) is fixedly connected to the upper surface of the adjustment plate (54), and the other end is fixedly connected to the lower surface of the lower platform (24).
9. A plastic product pull-out force testing device with intelligent pressure regulation function according to claim 8, characterized in that: The impact-resistant unit (5) also includes a container (56), a pull rod (57), a bar magnet (58), an adjusting spring (59), an induction coil (510), and a fixed cylinder (511). There are two wedge blocks (53), and both wedge blocks (53) are slidably connected to the container (56) via push rods. The ends of the two push rods located inside the container (56) abut against each other. The container (56) is fixedly connected to the test chamber (1). The tube is filled with magnetorheological fluid. One end of the pull rod (57) is fixedly connected to the wedge block (53), and the other end of the pull rod (57) is fixedly connected to the bar magnet (58). The bar magnet (58) is located inside the fixed cylinder (511). The bar magnet (58) is connected to the test chamber (1) through the adjusting spring (59). The induction coil (510) is fixedly installed inside the fixed cylinder (511). The fixed cylinder (511) is fixedly connected to the test chamber (1).
10. A plastic product pull-out force testing device with intelligent pressure adjustment function according to claim 8, characterized in that: A magnet is provided at one end of the wedge block (53) near the electromagnet (51).