Tail end anti-misfeed device for a progressive stamping die

Abstract

The present application relates to the technical field of stamping equipment, and discloses a stamping progressive die tail end mistaken feeding prevention device, which comprises a mounting seat, a buffer rod, a rotation stopping plate, a reset spring, a mounting block, a limiting guide assembly, a guide sleeve, a first guide plate, a pressure detection assembly and a gradient magnetic adjustment assembly; the mounting seat is internally embedded with a guide sliding sleeve; the buffer rod is slidingly fitted in the guide sliding sleeve, one end of the buffer rod is fixedly connected with a blocking block, and the other end is fixedly connected with a threaded rod; the rotation stopping plate is arranged on the threaded rod; and the reset spring is sleeved outside the buffer rod and abuts between the blocking block and the mounting seat; the present application solves the problem that the prior art can only detect multiple feeding and has a detection blind area for less feeding, realizes bidirectional and comprehensive detection of less feeding and multiple feeding, and provides dead angle-free feeding safety protection for progressive die production.

Description

Technical Field

[0001] This invention relates to the field of stamping equipment technology, and in particular to a device for preventing misfeeding at the tail end of a progressive stamping die. Background Technology

[0002] Progressive stamping dies can complete multiple complex processes such as blanking, bending, drawing, forming, and assembly in a single stamping stroke. They offer advantages such as high production efficiency, high automation, safe and reliable operation, and the ability to process complex parts, and are widely used in mass production fields such as electronics, IT, instrumentation, and automobiles. However, in actual production, inaccurate feeding often occurs due to improper feeder adjustment, strip bending and deformation, foreign object contamination, or feeder malfunction. If too little or too much material is fed, the blanks at each station cannot be accurately fed into the die cavity. If the die continues to stamp under this incorrect feeding condition, it will inevitably lead to product scrap. In severe cases, it can even cause die breakage, die fracture, and other die damage accidents, resulting in huge economic losses.

[0003] To address the aforementioned issues, various progressive die anti-misfeed detection devices have been developed within the industry. For example, the utility model patent with authorization announcement number CN210907779U discloses a cold stamping progressive die feeding anti-misfeed device. This device employs a two-stage anti-misfeed mechanism, where the material strip pushes the first-stage anti-misfeed mechanism backward to contact the second-stage anti-misfeed mechanism, thereby achieving multi-feed detection.

[0004] However, this device has the following shortcomings in practical applications: It primarily detects overfeeding faults and lacks effective identification capabilities for underfeeding (i.e., incomplete feeding). When underfeeding occurs, the conveyor belt fails to push the primary error-proofing mechanism to the point of contacting the secondary error-proofing mechanism, preventing the device from outputting an alarm signal and creating a detection blind spot. In actual production, both underfeeding and overfeeding can lead to mold accidents; the device's ability to detect only overfeeding while ignoring underfeeding fails to meet the comprehensive requirements for preventing misfeeding. Summary of the Invention

[0005] In view of the technical problem that existing anti-misfeed detection devices proposed in the background art are mainly for detecting overfeeding faults and lack effective identification capabilities for underfeeding (i.e., incomplete feeding), the present invention provides an anti-misfeeding device for the tail end of a stamping progressive die.

[0006] The technical solution adopted in this invention is: a stamping progressive die tail end anti-misfeeding device, comprising: a mounting base, a buffer rod, an anti-rotation plate, a return spring, a mounting block, a limit guide assembly, a guide sleeve, a first guide plate, a pressure detection assembly, and a gradient magnetic adjustment assembly; the mounting base has a guide sleeve embedded inside; the buffer rod is slidably fitted inside the guide sleeve, one end of the buffer rod is fixedly connected to a blocking block, and the other end is fixedly connected to a threaded rod; the anti-rotation plate is disposed on the threaded rod; the return spring is sleeved on the outside of the buffer rod and abuts against the blocking block and the mounting base; the mounting block is fixedly connected to the outside of the mounting base, and a detection device is installed on the mounting block. A sensor; a limiting guide assembly is disposed between the mounting block and the anti-rotation plate to restrict the linear movement of the anti-rotation plate; a guide sleeve is fixedly connected to the outside of the anti-rotation plate; a first guide plate is slidably connected inside the second guide sleeve; a pressure detection assembly is disposed between the first guide plate and the guide sleeve to detect the pressure borne by the first guide plate; a gradient magnetic adjustment assembly is disposed on the outside of the mounting base and located on the movement path of the first guide plate; when the first guide plate moves linearly outward with the anti-rotation plate, the repulsive force of the gradient magnetic adjustment assembly on the first guide plate gradually increases, thereby causing the pressure value detected by the pressure detection assembly to gradually increase.

[0007] A further feature of the present invention is that the external thread of the threaded rod is connected to a first clamping nut and a second clamping nut, which clamp and fix the anti-rotation plate.

[0008] A further embodiment of the present invention is that the limiting guide component includes a limiting groove disposed outside the mounting block and a limiting block slidably connected within the limiting groove, wherein the limiting block is fixedly connected to the anti-rotation plate.

[0009] A further embodiment of the present invention is that the guide sleeve is provided with an installation groove, the side wall of the installation groove is provided with a sliding groove, a slider is slidably connected in the sliding groove, the slider is fixedly connected to the first guide plate, and a first spring is connected between the slider and the sliding groove. The pressure detection assembly includes an abutment block and a pressure sensor. The pressure sensor is fixedly connected in a mounting groove. A guide rod is fixedly connected to the outside of the abutment block. A guide hole is provided in the first guide plate. The guide rod is slidably connected to the guide hole. A first mounting hole is provided in the first guide plate. A second spring is fixedly installed in the first mounting hole. One end of the second spring is fixedly connected to the abutment block.

[0010] A further configuration of the present invention is that a control box and an alarm assembly are fixedly connected to the outside of the mounting base. The control box contains a first control unit and a second control unit. The alarm assembly includes a first alarm and a second alarm. The detection sensor and the first alarm are both electrically coupled to the first control unit. The pressure sensor and the second alarm are both electrically coupled to the second control unit.

[0011] The present invention is further configured such that the gradient magnetic adjustment component includes a fixed frame fixedly connected to the outside of the mounting base, a plurality of first permanent magnets fixedly connected to the fixed frame in sequence along the moving direction of the first guide plate, a mounting frame fixedly connected to the outside of the first guide plate, and a second permanent magnet fixedly connected to the mounting frame. The magnetic strength of each of the first permanent magnets gradually increases along the moving direction of the first guide plate. The first permanent magnet and the second permanent magnet are arranged with the same pole facing each other to generate a repulsive force. When the first guide plate moves outward in a straight line with the anti-rotation plate, the second permanent magnet approaches each of the first permanent magnets in turn, and the repulsive force it receives gradually increases, thereby increasing the pressure value detected by the pressure detection component.

[0012] A further embodiment of the present invention is that a guide shell is fixedly connected to the outside of the mounting bracket, a second guide plate is slidably connected in the guide shell, a scraper is fixedly connected to one side of the second guide plate, a second mounting hole is provided in the second guide plate, a third spring is connected between the second mounting hole and the guide shell, and the scraper is in contact with the first permanent magnet.

[0013] A further feature of the present invention is that the top and bottom of the mounting bracket are both fixedly connected to a surrounding plate.

[0014] The present invention is further configured such that the first control unit includes: The first signal acquisition module is used to acquire the position signal of the detection sensor in real time, and includes photoelectric isolation and filtering circuits to suppress electromagnetic interference and vibration noise. The first threshold storage module is a non-volatile memory that pre-stores the effective level logic and anti-jitter time parameters for normal material conveyor positioning, and supports on-site parameter modification and power-off saving. The first comparison module compares the filtered arrival signal with the valid level logic. When the arrival signal is abnormal and the duration exceeds the set multiple of the anti-shake time and the normal feeding cycle, it is determined that the feeding is not in place or the material belt is missing, and a first trigger signal is generated. The first alarm drive module, in response to the first trigger signal, controls the first alarm to emit a continuous audible and visual alarm and outputs an emergency stop signal to the stamping equipment.

[0015] The present invention is further configured such that the second control unit includes: The second signal acquisition module is used to acquire the analog voltage signal output by the pressure sensor in real time, and convert it into a digital pressure value corresponding to the displacement of the first guide plate through analog-to-digital conversion and moving average filtering. The second threshold storage module is a non-volatile memory that pre-stores multiple sets of pressure thresholds corresponding to multiple position intervals of the second permanent magnet relative to each of the first permanent magnets. The position intervals include at least a severe underfeed interval, a slight underfeed interval, a normal interval, a slight overfeed interval, and a severe overfeed interval. The second comparison module compares the digital pressure value with the multiple sets of pressure thresholds to determine the specific position range of the second permanent magnet and generates different levels of trigger signals according to the degree of deviation. The second alarm drive module responds to different levels of trigger signals and controls the second alarm to emit audible and visual alarm signals of different frequencies and rhythms. The alarm frequency is positively correlated with the degree of deviation, and the alarm rhythm is used to distinguish between insufficient and excessive signal transmission.

[0016] The beneficial effects of this invention are: I. Compared with existing technologies, this invention overcomes the shortcomings of existing technologies, which can only detect overfeeding and have blind spots in underfeeding detection. It achieves comprehensive bidirectional detection of both overfeeding and underfeeding, providing seamless feeding safety protection for progressive die production. A displacement detection method combining a gradient magnetic adjustment component and a pressure detection component is employed. Multiple sets of permanent magnets with gradually increasing magnetic strength along the direction of movement generate a gradient repulsive force, accurately converting the linear displacement of the material strip pushing the blocking block into pressure changes recognizable by the pressure detection component. By using a preset pressure threshold range, it can accurately distinguish between underfeeding, normal feeding, and overfeeding states, filling the technological gap of traditional devices that cannot detect underfeeding. The limiting guide component strictly constrains the anti-rotation plate to move only linearly along the buffer rod axis, completely avoiding detection signal distortion caused by the offset of moving parts, ensuring the accuracy of the correspondence between pressure values ​​and material strip displacement, and significantly improving the reliability of detection results. Combined with the detection sensor on the mounting block, it can further achieve rapid detection of extreme faults such as complete material loss or breakage, constructing a full-range detection system from slight offset to severe material shortage. Once an abnormality in feeding is detected, the device can immediately trigger an alarm, effectively preventing batch scrapping of products caused by misfeeding, as well as serious mold accidents such as punch breakage and die rupture.

[0017] II. Compared with existing technologies, this invention significantly improves fault handling efficiency and production continuity through the independent operation of the first and second control units and a hierarchical alarm mechanism. The first control unit handles emergency faults with a millisecond-level response speed. Once a material strip is detected as missing, it immediately triggers an audible and visual alarm and automatically cuts off the emergency stop circuit of the stamping equipment to prevent mold damage. The second control unit divides the detection stroke into five fine intervals. Different frequencies of alarm sounds distinguish the severity of the deviation, and different rhythms of alarm signals distinguish the direction of underfeeding and overfeeding. Operators can quickly determine the fault type and take corresponding measures without checking the equipment. For minor deviations, the feeding parameters can be adjusted without stopping the machine, significantly reducing unnecessary downtime and improving the effective uptime of the equipment.

[0018] Third, compared with the prior art, this invention improves the environmental adaptability and versatility of the device and reduces maintenance costs through a passive self-cleaning structure and modular adjustable settings. The upper and lower enclosures of the mounting frame form a semi-enclosed protective space, which, together with the follow-up scraper and the third spring automatic compensation structure, can automatically remove dust, oil, and metal filings from the surface of the first permanent magnet during device operation, ensuring long-term magnetic stability and avoiding detection accuracy decay; the double-nut clamping adjustment structure can flexibly adjust the axial position of the anti-rotation plate to adapt to strips of different thicknesses and materials and various specifications of stamping dies. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the mounting base in this invention. Figure 1 ; Figure 3 This is a schematic diagram of the mounting base in this invention. Figure 2 ; Figure 4 yes Figure 3 Enlarged structural diagram of region A in the middle; Figure 5 This is a schematic diagram of the structure of the fixing frame in this invention; Figure 6 This is a cross-sectional structural diagram of the guide sleeve in this invention; Figure 7 yes Figure 6 A magnified structural diagram of region B in the middle; Figure 8 This is a schematic diagram of the structure of the second permanent magnet in this invention; Figure 9 This is a schematic diagram of the guide shell structure in this invention; Figure 10 This is a cross-sectional structural diagram of the guide shell in this invention.

[0020] The diagram is marked as follows: 1. Mounting base; 2. Control box; 3. Alarm assembly; 4. Buffer rod; 5. Return spring; 6. Blocking block; 7. Guide sleeve; 8. Mounting block; 9. Detection sensor; 10. Limiting groove; 11. Limiting block; 12. Threaded rod; 13. First clamping nut; 14. Second clamping nut; 15. Anti-rotation plate; 16. Fixing frame; 17. Guide sleeve; 18. First guide plate; 19. Mounting frame; 20. Enclosure; 21. Guide shell; 22. Second guide plate; 23. Scraper; 24. First permanent magnet; 25. Second permanent magnet; 26. Mounting groove; 27. Slide groove; 28. Slider; 29. ​​First spring; 30. First mounting hole; 31. Second spring; 32. Abutment block; 33. Pressure sensor; 34. Guide rod; 35. Guide hole; 36. Second mounting hole; 37. Third spring. Detailed Implementation

[0021] In the description of this invention, it should be noted that the terms "front", "up", "down", "left", "right", "vertical", "horizontal", 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.

[0022] The following is in conjunction with the appendix Figure 1-10 The present invention will be further described below.

[0023] To address the problems existing in the background art, this application proposes the following technical solution: Example 1: The anti-misfeeding device at the tail end of the progressive die includes a mounting base 1, a buffer rod 4, an anti-rotation plate 15, a return spring 5, a mounting block 8, and a limiting guide assembly. The mounting base 1 has a guide sleeve 7 embedded inside. The buffer rod 4 is slidably fitted within the guide sleeve 7, with a blocking block 6 fixedly connected to one end of the buffer rod 4 and a threaded rod 12 fixedly connected to the other end. The anti-rotation plate 15 is mounted on the threaded rod 12. The return spring 5 is sleeved on the outside of the buffer rod 4 and abuts against the blocking block 6 and the mounting base 1. The mounting block 8 is fixedly connected to the outside of the mounting base 1, and a detection sensor 9 is mounted on the mounting block 8. The limiting guide assembly is located between the mounting block 8 and the anti-rotation plate 15 to limit the linear movement of the anti-rotation plate 15. The detection sensor 9 is preferably an inductive proximity sensor (such as an Omron E2E-X5ME1).

[0024] In this embodiment, the mounting base 1 serves as the rigid load-bearing base of the entire device, providing a precise installation reference for all moving parts. The embedded guide sleeve 7 is made of self-lubricating copper-based alloy or graphite copper, with a low coefficient of friction. It provides high-precision linear motion guidance for the buffer rod 4 and effectively reduces sliding wear, extending the service life of the components. The buffer rod 4, as the core of force and displacement transmission, is made of heat-treated round steel, which has high strength and good toughness, and can smoothly convert the thrust of the conveyor belt into its own axial displacement. The blocking block 6 is made of wear-resistant polyurethane material covering the metal base, which flexibly contacts the edge of the conveyor belt. This ensures reliable force transmission without scratching the surface of the conveyor belt or causing edge deformation, thus avoiding affecting the appearance quality and dimensional accuracy of subsequent stamped parts. The return spring 5 has good elastic recovery capability and can automatically push the buffer rod 4 to quickly return to its original position after the conveyor belt passes through. It requires no additional power source and has a simple and reliable structure. The mounting block 8 provides a stable mounting platform for the detection sensor 9, ensuring that the relative position of the sensor and the anti-rotation plate 15 is always accurate, improving the reliability of the detection results. The limiting guide assembly fundamentally restricts the rotational freedom of the anti-rotation plate 15, ensuring that it can only move linearly along the buffer rod 4 axis, thus completely avoiding the distortion and misjudgment of the detection signal caused by the rotation of the anti-rotation plate 15.

[0025] In this embodiment, the threaded rod 12 is externally threaded with a first clamping nut 13 and a second clamping nut 14, which clamp and fix the anti-rotation plate 15. The limiting guide assembly includes a limiting groove 10 disposed outside the mounting block 8 and a limiting block 11 slidably connected within the limiting groove 10. The limiting block 11 is fixedly connected to the anti-rotation plate 15. The guide sleeve 17 is provided with a mounting groove 26, and the side wall of the mounting groove 26 is provided with a sliding groove 27. A slider 28 is slidably connected within the sliding groove 27. The slider 28 is fixedly connected to the first guide plate 18, and a first spring 29 is connected between the slider 28 and the sliding groove 27.

[0026] In the above technical solution, the clamping and fixing method of the first clamping nut 13 and the second clamping nut 14 utilizes the self-locking characteristic of the thread and the mutual clamping force between the two nuts to form a reliable anti-loosening structure. By tightening the first clamping nut 13 and the second clamping nut 14, the axial position of the anti-rotation plate 15 on the threaded rod 12 can be adjusted, thereby changing the pre-compression of the return spring 5 and the initial extension length of the blocking block 6. This allows it to adapt to strips of different thicknesses, materials, and feeding strokes, as well as stamping dies of different specifications, improving the versatility and applicability of the device. The sliding fit structure between the limiting groove 10 and the limiting block 11 is simple to process, has high guiding accuracy, and strong load-bearing capacity. It can strictly constrain the movement trajectory of the anti-rotation plate 15, ensuring that it can only move in a straight line along the axial direction of the buffer rod 4. This eliminates the detection error caused by the rotation of the anti-rotation plate 15 and ensures that the detection sensor 9 can accurately capture the positional change of the anti-rotation plate 15. The mounting groove 26 within the guide sleeve 17 provides a closed mounting space for the first guide plate 18 and subsequent pressure detection components, effectively preventing dust, oil, and metal shavings from the stamping workshop from entering and avoiding component jamming and corrosion. The cooperation between the slide groove 27 and the slider 28 provides stable linear motion guidance for the first guide plate 18, ensuring that its movement trajectory is consistent with the axis of the buffer rod 4. The first spring 29, as an elastic buffer element, absorbs the impact vibration generated during the movement of the first guide plate 18, preventing rigid collisions from damaging components. Furthermore, it can quickly reset the first guide plate 18 after the external force disappears, preparing it for the next detection.

[0027] In this embodiment, the mounting base 1 is externally fixedly connected to a control box 2 and an alarm component 3. The control box 2 is equipped with a first control unit and a second control unit. The alarm component 3 includes a first alarm and a second alarm. The detection sensor 9 and the first alarm are both electrically coupled to the first control unit.

[0028] In the above technical solution, control box 2 adopts a sealed sheet metal structure, with rubber sealing strips added to the joints, providing IP54-level dustproof and waterproof performance. This effectively protects the internal control circuits and electronic components from the corrosion of dust, oil, and moisture in the stamping workshop. The first and second control units adopt independent modular designs, each responsible for different types of detection and alarm tasks. The hardware and software are independent of each other, with clear division of labor and no interference. Even if one control unit fails, the other can still work normally, significantly improving the overall reliability and fault tolerance of the system. Alarm component 3 adopts a dual-alarm differentiated design, corresponding to different types and severity of feeding anomalies. This allows operators to quickly distinguish the type of fault in a noisy production environment, improving fault handling efficiency. The first alarm uses a bright red LED light and a high-decibel buzzer to indicate emergency faults such as missing or severely misaligned material; the second alarm uses a yellow LED light and an adjustable frequency buzzer to indicate early warning faults such as slight material deviation.

[0029] In addition, a waterproof operation panel can be installed on the outside of the control box 2, which integrates a power switch, an alarm reset button and a parameter adjustment knob, to facilitate on-site debugging and operation by operators.

[0030] In this embodiment, the first control unit includes: The first signal acquisition module is used to acquire the position signal of the detection sensor 9 in real time, and includes photoelectric isolation and filtering circuits to suppress electromagnetic interference and vibration noise. The first threshold storage module is a non-volatile memory that pre-stores the effective level logic and anti-jitter time parameters for normal material conveyor positioning, and supports on-site parameter modification and power-off saving. The first comparison module compares the filtered arrival signal with the valid level logic. When the arrival signal is abnormal and the duration exceeds the set multiple of the anti-shake time and the normal feeding cycle, it is determined that the feeding is not in place or the material belt is missing, and a first trigger signal is generated. The first alarm drive module, in response to the first trigger signal, controls the first alarm to emit a continuous audible and visual alarm and outputs an emergency stop signal to the stamping equipment.

[0031] In the above technical solution, the first control unit is the core for realizing the detection of the absence and serious misalignment of the material belt. It adopts a layered and modular software architecture, with each module having independent functions and clear interfaces, which facilitates development, debugging and maintenance.

[0032] The first signal acquisition module is responsible for acquiring the output signal of the detection sensor 9 in real time, and performing digital filtering, smoothing and level conversion on the raw signal to remove noise glitches caused by environmental electromagnetic interference and vibration, so as to ensure the purity and accuracy of the input signal.

[0033] The first threshold storage module is used to store the effective sensing threshold obtained in advance through on-site calibration. This threshold is determined based on the stable output signal of the detection sensor 9 when the material belt is in normal position. It can accurately distinguish between the two states of the material belt being in position and not in position, while reserving a certain margin of error to avoid false alarms caused by slight signal fluctuations.

[0034] The first comparison module is the logic core of the control unit. It performs a fast comparison calculation between the pre-processed real-time signal and the stored effective sensing threshold. When the real-time signal is continuously lower than the threshold and exceeds the set anti-shake time, it is determined to be a feeding abnormality and the first trigger signal is immediately generated.

[0035] Upon receiving the trigger signal, the first alarm drive module immediately outputs a drive current to control the first alarm to emit a continuous audible and visual alarm signal. Simultaneously, it can output a switching signal to the stamping equipment's control system to achieve automatic shutdown protection. This control unit features fast response, accurate judgment, and strong anti-interference capabilities. It can issue an alarm and trigger a shutdown within milliseconds of a feeding anomaly, effectively preventing dry stamping or accidental stamping of the mold and protecting the mold and equipment safety.

[0036] The usage method of this embodiment is as follows: Fix the mounting base 1 to the outer wall of the tail end of the progressive die, aligning the blocking block 6 at the front end of the buffer rod 4 with the conveying edge of the strip. Adjust the axial position of the anti-rotation plate 15 on the threaded rod 12 by tightening the first clamping nut 13 and the second clamping nut 14, thereby setting the preload of the return spring 5 and ensuring that the blocking block 6 maintains appropriate initial contact pressure with the edge of the strip. At the same time, engage the limiting block 11 into the limiting groove 10 of the mounting block 8, restricting the anti-rotation plate 15 to move only in a straight line.

[0037] When the stamping equipment drives the material belt forward, the edge of the material belt pushes the blocking block 6, causing the buffer rod 4 to slide backward within the guide sleeve 7. The return spring 5 is compressed, and the anti-rotation plate 15 moves backward along with the buffer rod 4. The limiting block 11 slides within the limiting groove 10 to maintain linear motion. As the anti-rotation plate 15 moves, the detection sensor 9 on the mounting block 8 continuously monitors whether the material belt has reached the preset position. The first signal acquisition module of the first control unit acquires the position signal of the detection sensor 9 in real time, and the first comparison module compares the signal with the valid sensing threshold pre-stored in the first threshold storage module. If the position signal is lower than the threshold, it is determined that the feeding is insufficient or the material belt is missing. The first comparison module generates a first trigger signal, and the first alarm drive module controls the first alarm to issue an alarm (e.g., audible and visual prompt) to remind the operator to check whether the feeding is insufficient or the material belt is exhausted.

[0038] Example 2: This embodiment differs from Embodiment 1 in that it further includes: a guide sleeve 17, a first guide plate 18, a pressure detection component, and a gradient magnetic adjustment component; the guide sleeve 17 is fixedly connected to the outside of the anti-rotation plate 15; the first guide plate 18 is slidably connected inside the guide sleeve 17; the pressure detection component is disposed between the first guide plate 18 and the guide sleeve 17, and is used to detect the pressure borne by the first guide plate 18; the gradient magnetic adjustment component is disposed on the outside of the mounting base 1 and is located on the moving path of the first guide plate 18; when the first guide plate 18 moves outward linearly with the anti-rotation plate 15, the repulsive force of the gradient magnetic adjustment component on the first guide plate 18 gradually increases, thereby causing the pressure value detected by the pressure detection component to gradually increase.

[0039] This embodiment, based on the basic detection function of Embodiment 1, introduces a position detection technology combining magnetic adjustment and pressure detection, significantly expanding the detection range and functional completeness of the device. The guide sleeve 17 provides a stable installation reference and sliding guide for the first guide plate 18, ensuring that the movement trajectory of the first guide plate 18 is strictly parallel to the axis of the buffer rod 4. The pressure detection component is installed in the enclosed space between the first guide plate 18 and the guide sleeve 17, capable of detecting the magnitude of the magnetic force on the first guide plate 18 in real time and linearly converting it into an electrical signal output.

[0040] In this embodiment, the gradient magnetic adjustment component adopts the non-contact permanent magnet interaction principle to convert the linear displacement of the first guide plate 18 into pressure change.

[0041] In this embodiment, the pressure detection component includes a contact block 32 and a pressure sensor 33. The pressure sensor 33 is fixedly connected in the mounting groove 26. A guide rod 34 is fixedly connected to the outside of the contact block 32. A guide hole 35 is provided in the first guide plate 18. The guide rod 34 is slidably connected to the guide hole 35. A first mounting hole 30 is provided in the first guide plate 18. A second spring 31 is fixedly installed in the first mounting hole 30. One end of the second spring 31 is fixedly connected to the contact block 32. The pressure sensor 33 and the second alarm are both electrically coupled to the second control unit.

[0042] In the above technical solution, the pressure detection component is the core component for realizing displacement-pressure conversion and accurate detection. It can convert the non-contact magnetic force received by the first guide plate 18 into a quantifiable electrical signal, providing data support for subsequent position judgment and graded alarm.

[0043] The contact block 32 is made of high-strength stainless steel with a polished and hardened surface, exhibiting good wear resistance and resistance to deformation over long-term use. It can evenly bear the pressure transmitted by the second spring 31. The guide rod 34 and the guide hole 35 on the first guide plate 18 are fitted with clearance, providing linear motion guidance for the contact block 32. This ensures that the pressure is always applied vertically and evenly to the sensing center surface of the pressure sensor 33, avoiding detection errors and sensor damage caused by off-center loading.

[0044] The second spring 31, as an elastic transmission element, is made of precision spring steel wire and has good elastic linearity. It can smoothly and evenly transmit the magnetic force received by the first guide plate 18 to the pressure sensor 33. At the same time, it plays a role in buffering and shock absorption, absorbing the impact force brought by the vibration of the stamping equipment, protecting the pressure sensor 33 from damage, and extending the service life of the sensor.

[0045] The pressure sensor 33 adopts a high-precision resistance strain gauge miniature pressure sensor, which integrates a Wheatstone bridge and signal conditioning circuit. It features fast response speed, high detection accuracy, small temperature drift, and strong anti-interference ability. It can capture minute pressure changes in real time and accurately reflect the position changes of the first guide plate 18.

[0046] In this embodiment, the gradient magnetic adjustment component includes a fixed frame 16 fixedly connected to the outside of the mounting base 1, a plurality of first permanent magnets 24 sequentially fixedly connected to the fixed frame 16 along the moving direction of the first guide plate 18, a mounting frame 19 fixedly connected to the outside of the first guide plate 18, and a second permanent magnet 25 fixedly connected to the mounting frame 19. The magnetic strength of each first permanent magnet 24 gradually increases along the moving direction of the first guide plate 18. The first permanent magnets 24 and the second permanent magnets 25 are arranged in a manner with the same pole facing each other to generate a repulsive force. When the first guide plate 18 moves outward in a straight line with the anti-rotation plate 15, the second permanent magnets 25 sequentially approach each of the first permanent magnets 24, and the repulsive force they receive gradually increases, thereby causing the pressure value detected by the pressure detection component to gradually increase.

[0047] In the above technical solution, multiple first permanent magnets 24 are made of neodymium iron boron strong magnetic material and are arranged at equal intervals along the moving direction of the first guide plate 18, with the magnetic strength increasing sequentially according to a preset gradient to form a stable gradient magnetic field. Second permanent magnets 25 are also made of neodymium iron boron material and are firmly fixed to the end of the first guide plate 18 by a mounting bracket 19. They are installed with the first permanent magnets 24 in a manner where their poles face each other, utilizing the principle of repulsion between like magnetic poles to generate a repulsive force. When the first guide plate 18 moves backward with the anti-rotation plate 15, the second permanent magnets 25 sequentially approach the first permanent magnets 24 with different magnetic strengths. As the magnetic force of the first permanent magnets 24 gradually increases, the repulsive force on the second permanent magnets 25 also increases monotonically, thus creating a one-to-one monotonic function relationship between the pressure value detected by the pressure detection component and the displacement of the first guide plate 18.

[0048] By pre-calibrating the pressure values ​​corresponding to different displacements, the actual position of the first guide plate 18 can be accurately calculated based on the pressure values ​​detected in real time, thereby accurately determining the feeding distance of the material belt.

[0049] The structure features a stable magnetic field distribution, unaffected by environmental factors such as temperature, humidity, and dust. Long-term use results in minimal magnetic force attenuation, ensuring long-term stability of detection accuracy. Furthermore, the modular permanent magnet design facilitates replacement and adjustment, allowing for flexible configuration of the number of permanent magnets and magnetic force gradients to suit different detection strokes and accuracy requirements.

[0050] The second control unit includes: The second signal acquisition module is used to acquire the analog voltage signal output by the pressure sensor 33 in real time, and convert it into a digital pressure value corresponding to the displacement of the first guide plate 18 through analog-to-digital conversion and moving average filtering. The second threshold storage module is a non-volatile memory that pre-stores multiple sets of pressure thresholds corresponding to multiple position intervals of the second permanent magnet 25 relative to each of the first permanent magnets 24. The position intervals include at least a severe underfeed interval, a slight underfeed interval, a normal interval, a slight overfeed interval, and a severe overfeed interval. The second comparison module compares the digital pressure value with the multiple sets of pressure thresholds to determine the specific position range of the second permanent magnet 25, and generates different levels of trigger signals according to the degree of deviation. The second alarm drive module responds to different levels of trigger signals and controls the second alarm to emit audible and visual alarm signals of different frequencies and rhythms. The alarm frequency is positively correlated with the degree of deviation, and the alarm rhythm is used to distinguish between insufficient and excessive signal transmission.

[0051] In this embodiment, the second control unit is the core of realizing graded detection and intelligent alarm of feeding deviation. It can process, analyze and judge the analog signal output by the pressure detection component in real time, accurately identify the feeding position of the material belt, and issue different levels of warning signals according to the degree of deviation.

[0052] The second signal acquisition module is responsible for amplifying, filtering, and converting the weak analog voltage signal output by the pressure sensor 33 into an analog-to-digital value to generate a high-precision digital pressure value, providing a reliable data basis for subsequent comparison and judgment.

[0053] The second threshold storage module stores multiple sets of pressure thresholds obtained through on-site calibration in advance. For example, the entire detection stroke is divided into three major intervals: underfeed, normal, and overfeed (not limited to this). The two abnormal intervals are further subdivided into multiple sub-intervals, each sub-interval corresponding to a different degree of positional deviation, thus realizing a fine division of the feeding offset.

[0054] The second comparison module is the logic core of the control unit. It performs rapid comparison calculations between the real-time collected digital pressure values ​​and the stored threshold values ​​of each interval to accurately determine the current position interval and degree of offset of the second permanent magnet 25, and generates the corresponding alarm frequency level according to the magnitude of the offset.

[0055] The second alarm drive module outputs PWM drive signals of different frequencies according to the alarm frequency level, controlling the second alarm to emit audible and visual alarms of different frequencies.

[0056] This tiered alarm system allows operators to intuitively judge the severity of feeding abnormalities simply by hearing or seeing. For minor deviations, the feeder parameters can be adjusted without stopping the machine, while for severe deviations, the machine must be stopped immediately. This significantly improves fault handling efficiency, reduces unnecessary downtime and product scrap rates, and effectively enhances production efficiency.

[0057] In Embodiment 2, the detection sensor 9 and its first control unit from Embodiment 1 are retained to determine whether the conveyor belt is completely missing or severely under-delivered. When the detection sensor 9 triggers the first alarm, it indicates that the conveyor belt has not been delivered; when the pressure sensor 33 triggers the second alarm and outputs a changing frequency, it indicates that although the conveyor belt has been delivered, the offset exceeds the allowable range. These two mechanisms complement each other, achieving full-range monitoring from "presence or absence of material" to "more or less delivered".

[0058] In addition, the construction of the dual detection system enables this device to have all-round, blind-spot-free feeding anomaly detection capability, covering all possible situations from complete loss and breakage of the material belt to slight micron-level deviation, completely eliminating the detection blind spots existing in traditional single detection methods.

[0059] The detection sensor 9 boasts extremely fast response speed and low cost, capable of detecting emergencies such as severe material misalignment or material breakage within milliseconds. It promptly triggers the first alarm and automatic shutdown, preventing serious mold accidents such as punch breakage and die shattering caused by cavitation. The two detection methods serve as backups and complements each other; even if one method fails, the other continues to operate normally.

[0060] Meanwhile, dual detection can effectively cross-verify test results, significantly reduce false alarms and missed alarms, avoid unnecessary downtime caused by false alarms, and improve the effective uptime of the equipment.

[0061] Furthermore, the technical solutions of Embodiment 1 and Embodiment 2 can be used in combination or separately.

[0062] Example 3: The difference between this embodiment and embodiment two is that a surrounding plate 20 is fixedly connected to the top and bottom of the mounting frame 19, a guide shell 21 is fixedly connected to the outside of the mounting frame 19, a second guide plate 22 is slidably connected in the guide shell 21, a scraper 23 is fixedly connected to one side of the second guide plate 22, a second mounting hole 36 is provided in the second guide plate 22, a third spring 37 is connected between the second mounting hole 36 and the guide shell 21, and the scraper 23 is in contact with the first permanent magnet 24.

[0063] In this embodiment, a passive self-cleaning structure is added based on embodiment two. This structure can automatically remove dust, oil, and metal filings from the surface of the first permanent magnet 24, ensuring the long-term stability of the magnetic force and the detection accuracy. The upper and lower enclosures 20 of the mounting bracket 19 form a semi-enclosed protective space, which can block most of the splashed metal fragments and dust from entering the gradient magnetic adjustment component and reduce the deposition of contaminants on the surface of the permanent magnet.

[0064] The guide housing 21 is made of aluminum alloy and has an anodized surface, which makes it corrosion-resistant and wear-resistant. It is firmly fixed to the outside of the mounting bracket 19 with bolts, providing a stable sliding guide for the second guide plate 22.

[0065] The second guide plate 22 is made of engineering plastic, which is lightweight and has low sliding resistance, allowing it to slide smoothly within the guide housing 21. The scraper 23 is made of high wear-resistant nitrile rubber, which has good elasticity, wear resistance, and oil resistance, and can closely adhere to the surface of the first permanent magnet 24.

[0066] The third spring 37 is always compressed, providing a continuous and stable thrust to the second guide plate 22, ensuring that the scraper 23 remains in close contact with the surface of the first permanent magnet 24. Even if the scraper 23 experiences slight wear, it can automatically compensate for it. When the first guide plate 18 moves the second permanent magnet 25 back and forth, the scraper 23 moves synchronously with the first guide plate 18, thoroughly scraping away dust, oil, iron filings, and other debris from the surface of the first permanent magnet 24 during the movement, keeping the surface of the first permanent magnet 24 clean.

[0067] Furthermore, examples of the first control unit and the second control unit are illustrated below: First control unit (detects whether or not the material is in place, and for serious misalignment): The first control unit uses the industrial-grade general-purpose single-chip microcomputer STM32F103C8T6 as the core processor. It is responsible for detecting whether the material tape is completely missing or seriously out of position. It belongs to the switch-type emergency detection system.

[0068] The first signal acquisition module uses an inductive proximity sensor (preferably Omron E2E-X5ME1, NPN normally open type, 5mm detection distance, IP67 protection rating, specifically designed for metal strip detection) to acquire the strip's arrival signal in real time. The switch signal output by the inductive proximity sensor is first electrically isolated by a PC817 opto-isolator to effectively block electromagnetic interference generated by the stamping equipment from entering the main control circuit and protect the microcontroller's I / O ports. The isolated signal can be sent to an external Schmitt trigger 74HC14 (optional) for waveform shaping to further eliminate edge jitter. Finally, the signal is input to the PA0 pin of the STM32. The microcontroller internally generates a 1ms periodic interrupt using a TIM2 timer, and continuously samples the PA0 level at 1ms intervals in the interrupt service function. To prevent misjudgment caused by signal glitches due to stamping vibration, the program uses a "three-sampling confirmation method": only when three consecutive samples are low is the strip considered to be in place; if a high level appears after a single low level, it is considered an interference signal and directly filtered out. The filtered strip status is stored in a memory variable for subsequent comparison.

[0069] The first threshold storage module uses a non-volatile EEPROM chip AT24C02 (I2C interface, 2Kbit storage capacity) to pre-store the valid logic level for normal material arrival and the anti-jitter time parameters. When the system powers on, the microcontroller simulates the I2C bus timing through the PB6 (SCL clock line) and PB7 (SDA data line) pins, reading parameters from the designated address of the AT24C02 (0x00 stores the valid logic level, 0x01 stores the anti-jitter time) into memory. Operators can modify the parameters on-site using the buttons on the control box 2 panel. After modification, the microcontroller writes the new parameters to the corresponding address in the EEPROM, achieving power-off retention, thus adapting to material strips of different thicknesses and materials, as well as stamping dies of different specifications.

[0070] The first comparison module compares the filtered tape status signal with a preset valid level logic. When the tape not in place signal (high level) lasts for more than the preset anti-jitter time (e.g., 3ms) and further exceeds 1.5 times the normal feeding cycle, it is determined that the feeding is not in place or the tape is missing, and a first trigger signal is immediately generated. This judgment logic can both filter out transient interference and accurately identify the real feeding abnormality.

[0071] The first alarm drive module responds to the first trigger signal, controlling the first alarm to sound and triggering the automatic shutdown of the stamping equipment. The specific circuit is as follows: the microcontroller's PA1 pin outputs a high level, driving the S8050 NPN transistor to conduct via a 1kΩ base resistor, causing the HYD-2319 active buzzer (90dB high decibel) to emit a continuous sound; simultaneously, the PA2 pin outputs a low level, driving the SRD-05VDC-SL-C relay via the S8050 transistor, cutting off the emergency stop circuit of the stamping equipment and achieving automatic shutdown protection; the PA5 pin outputs a 1Hz PWM signal with a 50% duty cycle, driving a bright red LED to flash once per second. The alarm state continues until the operator manually presses the reset button.

[0072] Second control unit (graded detection of feeding offset): The second control unit uses an STM32F103C8T6 main control chip to detect the offset of the conveyor belt and implement graded early warning. This unit processes the analog signal output by pressure sensor 33 and belongs to the analog graded detection system.

[0073] The second signal acquisition module uses a resistance strain gauge miniature pressure sensor 33CZL635 (range 5kg, sensitivity 1.0±0.1mV / V, nonlinearity error ±0.03%FS) to detect the repulsive force on the first guide plate 18 in real time. When the second permanent magnet 25 moves with the first guide plate 18, the gradient repulsive force it experiences from the first permanent magnet 24 changes. This force is transmitted to the CZL635 pressure sensor 33 through the second spring 31 and the contact block 32. The sensor outputs a differential analog voltage signal of 0-20mV, which is sent to the HX711 dedicated weighing AD conversion module. The HX711 integrates a 128x programmable gain amplifier, which amplifies the millivolt-level signal and converts it into a digital signal through a 24-bit Σ-Δ ADC. The STM32 communicates with the HX711 through the PA3 (PD_SCK clock line) and PA4 (DOUT data line) pins, reading the 24-bit raw AD value according to the timing sequence. To eliminate random noise caused by high-frequency vibration of the stamping equipment, the microcontroller reads data every 15ms and uses a moving average filtering algorithm: maintaining a sampling window of length 3, subtracting the oldest data in the window after each new data reading, adding the new data, and calculating the arithmetic mean as the current pressure value. After calibration and conversion, this pressure value accurately reflects the displacement of the first guide plate 18, and thus corresponds to the feeding offset of the material strip.

[0074] The second threshold storage module also uses the AT24C02EEPROM chip, pre-storing multiple sets of pressure thresholds corresponding to multiple position intervals of the second permanent magnet 25 relative to each of the first permanent magnets 24 in an independent address space (0x02 to 0x0F). These thresholds include: severe underfeed upper limit threshold, slight underfeed upper limit threshold, normal range lower limit threshold, normal range upper limit threshold, slight overfeed lower limit threshold, and severe overfeed lower limit threshold. These threshold parameters are automatically read when the system is powered on. On-site calibration is supported: the operator enters calibration mode through the control box 2 panel, manually pushes the buffer rod 4 to the boundary of each position interval, and presses the confirmation key. The microcontroller automatically records the current pressure value and writes it to the EEPROM, thus adapting to the actual detection stroke of different molds and material strips.

[0075] The second comparison module compares the filtered and converted real-time pressure value with multiple pressure thresholds stored in the EEPROM to determine the specific position range of the second permanent magnet 25. This module divides the entire detection range into five sub-ranges: "Severe Under-delivery," "Slight Under-delivery," "Normal," "Slight Over-delivery," and "Severe Over-delivery." When the real-time pressure value is less than the upper threshold of the severe under-delivery range, it is determined to be a severe under-delivery; when it is greater than or equal to the upper threshold of the severe under-delivery range but less than the upper threshold of the slight under-delivery range, it is determined to be a slight under-delivery; when it is between the lower and upper limits of the normal range, it is determined to be normal and no alarm is triggered; when it is greater than the upper limit of the normal range but less than or equal to the lower limit of the slight over-delivery range, it is determined to be a slight over-delivery; when it is greater than the lower limit of the slight over-delivery range, it is determined to be a severe over-delivery. Different levels of trigger signals (Level 2 and Level 1) are generated for slight under-delivery and slight over-delivery, respectively; a Level 3 trigger signal is generated uniformly for severe under-delivery and severe over-delivery.

[0076] The second alarm drive module controls the second alarm to emit audible and visual alarms of different frequencies and rhythms based on the alarm level output by the second comparison module. The microcontroller uses the internal TIM3 timer to generate a PWM signal, which is output through the PB0 pin. The alarm frequency is positively correlated with the degree of deviation, and the rhythm distinguishes the direction of deviation: for slight overfeeding (level 1), a PWM signal with a frequency of 1Hz and a duty cycle of 50% is output, driving the yellow LED to flash slowly once per second, while the buzzer emits a long-interval "beep-beep-" intermittent sound; for slight underfeeding (level 2), a PWM signal with a frequency of 2Hz is output, the yellow LED flashes at a medium speed twice per second, and the buzzer emits a short-interval "beep-beep-" sound; for severe deviation (level 3), a PWM signal with a frequency of 10Hz is output, the yellow LED flashes rapidly (10 times per second), and the buzzer emits a continuous and rapid alarm sound. Operators can intuitively judge the severity and direction of the feeding abnormality by hearing or sight alone. For slight deviations, the feeder parameters can be adjusted without stopping the machine; for severe deviations, the machine must be stopped immediately.

[0077] The collaborative operation of the dual detection system: The first and second control units operate independently and serve as backups for each other, constructing a comprehensive, blind-spot-free feeding anomaly detection system. The first control unit detects whether the material strip is completely missing or severely misaligned with the die with millisecond-level response speed. Once triggered, it immediately issues a continuous red audible and visual alarm and automatically stops the stamping equipment, effectively preventing serious accidents such as punch breakage and die shattering caused by dry stamping. The second control unit performs refined, graded monitoring of feeding deviation, using variable-frequency, variable-rhythm audible and visual alarms to indicate the specific degree and direction of the deviation to the operator. The two detection methods are cross-validated; even if one fails, the other continues to operate normally, significantly improving the overall reliability and safety of the system while avoiding unnecessary downtime due to false alarms.

[0078] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0079] Although embodiments of the invention have been shown and described, the scope of the invention will be defined by the appended claims and their equivalents by those skilled in the art.

Claims

1. A device for preventing misfeeding at the tail end of a progressive die for stamping, characterized in that, include: Mounting base (1), with guide sleeve (7) embedded inside; The buffer rod (4) is slidably fitted inside the guide sleeve (7). One end of the buffer rod (4) is fixedly connected to a blocking block (6), and the other end is fixedly connected to a threaded rod (12). An anti-rotation plate (15) is provided on the threaded rod (12); The return spring (5) is sleeved on the outside of the buffer rod (4) and abuts against the blocking block (6) and the mounting base (1); Mounting block (8) is fixedly connected to the outside of mounting base (1), and a detection sensor (9) is mounted on mounting block (8). A limiting guide assembly is disposed between the mounting block (8) and the anti-rotation plate (15) to limit the linear movement of the anti-rotation plate (15); The guide sleeve (17) is fixedly connected to the outside of the anti-rotation plate (15); The first guide plate (18) is slidably connected inside the second guide sleeve (17); A pressure detection component is disposed between the first guide plate (18) and the guide sleeve (17) for detecting the pressure borne by the first guide plate (18); The gradient magnetic adjustment component is disposed outside the mounting base (1) and located on the moving path of the first guide plate (18). When the first guide plate (18) moves outward in a straight line with the anti-rotation plate (15), the repulsive force of the gradient magnetic adjustment component on the first guide plate (18) gradually increases, thereby increasing the pressure value detected by the pressure detection component.

2. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 1, characterized in that, The threaded rod (12) is externally threaded with a first clamping nut (13) and a second clamping nut (14), which clamp and fix the anti-rotation plate (15).

3. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 1, characterized in that, The limiting guide assembly includes a limiting groove (10) disposed outside the mounting block (8) and a limiting block (11) slidably connected in the limiting groove (10), wherein the limiting block (11) is fixedly connected to the anti-rotation plate (15).

4. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 1, characterized in that, The guide sleeve (17) is provided with an installation groove (26), and the side wall of the installation groove (26) is provided with a sliding groove (27). A slider (28) is slidably connected in the sliding groove (27). The slider (28) is fixedly connected to the first guide plate (18), and a first spring (29) is connected between the slider (28) and the sliding groove (27). The pressure detection assembly includes an abutment block (32) and a pressure sensor (33). The pressure sensor (33) is fixedly connected in the mounting groove (26). A guide rod (34) is fixedly connected to the outside of the abutment block (32). A guide hole (35) is provided in the first guide plate (18). The guide rod (34) is slidably connected to the guide hole (35). A first mounting hole (30) is provided in the first guide plate (18). A second spring (31) is fixedly installed in the first mounting hole (30). One end of the second spring (31) is fixedly connected to the abutment block (32).

5. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 4, characterized in that, The mounting base (1) is externally fixedly connected to a control box (2) and an alarm component (3). The control box (2) is equipped with a first control unit and a second control unit. The alarm component (3) includes a first alarm and a second alarm. The detection sensor (9) and the first alarm are both electrically coupled to the first control unit. The pressure sensor (33) and the second alarm are both electrically coupled to the second control unit.

6. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 5, characterized in that, The gradient magnetic adjustment assembly includes a fixed frame (16) fixedly connected to the outside of the mounting base (1), a plurality of first permanent magnets (24) fixedly connected to the fixed frame (16) in sequence along the moving direction of the first guide plate (18), a mounting frame (19) fixedly connected to the outside of the first guide plate (18), and a second permanent magnet (25) fixedly connected to the mounting frame (19). The magnetic strength of each of the first permanent magnets (24) gradually increases along the moving direction of the first guide plate (18). The first permanent magnets (24) and the second permanent magnets (25) are arranged in a manner with the same pole facing each other to generate a repulsive force. When the first guide plate (18) moves outward in a straight line with the anti-rotation plate (15), the second permanent magnets (25) approach each of the first permanent magnets (24) in turn, and the repulsive force they receive gradually increases, thereby causing the pressure value detected by the pressure detection component to gradually increase.

7. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 5, characterized in that, The mounting bracket (19) is fixedly connected to a guide shell (21), and a second guide plate (22) is slidably connected in the guide shell (21). A scraper (23) is fixedly connected to one side of the second guide plate (22). A second mounting hole (36) is provided in the second guide plate (22). A third spring (37) is connected between the second mounting hole (36) and the guide shell (21). The scraper (23) is in contact with the first permanent magnet (24).

8. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 5, characterized in that, The top and bottom of the mounting bracket (19) are fixedly connected with a surrounding plate (20).

9. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 5, characterized in that, The first control unit includes: The first signal acquisition module is used to acquire the position signal of the detection sensor (9) in real time, and includes photoelectric isolation and filtering circuits to suppress electromagnetic interference and vibration noise; The first threshold storage module is a non-volatile memory that pre-stores the effective level logic and anti-jitter time parameters for normal material conveyor positioning, and supports on-site parameter modification and power-off saving. The first comparison module compares the filtered arrival signal with the valid level logic. When the arrival signal is abnormal and the duration exceeds the set multiple of the anti-shake time and the normal feeding cycle, it is determined that the feeding is not in place or the material belt is missing, and a first trigger signal is generated. The first alarm drive module, in response to the first trigger signal, controls the first alarm to emit a continuous audible and visual alarm and outputs an emergency stop signal to the stamping equipment.

10. The anti-misfeeding device at the tail end of the progressive die for stamping according to claim 6, characterized in that, The second control unit includes: The second signal acquisition module is used to acquire the analog voltage signal output by the pressure sensor (33) in real time, and convert it into a digital pressure value corresponding to the displacement of the first guide plate (18) through analog-to-digital conversion and moving average filtering. The second threshold storage module is a non-volatile memory that pre-stores multiple sets of pressure thresholds corresponding to multiple position intervals of the second permanent magnet (25) relative to each of the first permanent magnets (24). The position intervals include at least a severe underfeed interval, a slight underfeed interval, a normal interval, a slight overfeed interval, and a severe overfeed interval. The second comparison module compares the digital pressure value with the multiple pressure thresholds to determine the specific position range of the second permanent magnet (25) and generates different levels of trigger signals according to the degree of deviation. The second alarm drive module responds to different levels of trigger signals and controls the second alarm to emit audible and visual alarm signals of different frequencies and rhythms. The alarm frequency is positively correlated with the degree of deviation, and the alarm rhythm is used to distinguish between insufficient and excessive signal transmission.

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