Intelligent chain type smooth variable-speed conveying system and safety control method

Abstract

The invention relates to an intelligent chain type smooth variable-speed conveying system and a safety control method.The system comprises a rack, a conveying module and a conveying bottom plate, the tooth number of chain wheels installed on a driving axis and a driven axis in the conveying module changes according to a preset speed curve, and series transmission is achieved through chains; the conveying bottom plate is driven by the rollers to achieve position-dependent automatic smooth speed change, the intelligent monitoring system monitors the position and speed of the conveying bottom plate in real time through the photoelectric switch set and compares the position and speed with theoretical values to achieve fault self-diagnosis, and the anti-extrusion limiting switch set arranged at the discharging port can trigger active safety protection when the blocking risk is detected. Compared with the prior art, acceleration impact in the start-stop stage is eliminated, it is ensured that the materials are kept stable in the start-stop process, the safety of the conveying process is greatly improved, meanwhile, parallel, independent and non-interfering variable-speed conveying of the multiple materials is achieved, and the intelligent level and comprehensive benefits of a conveying system are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of industrial automation production technology, and in particular to a chain conveyor for material handling. Specifically, this invention relates to a high-performance conveying system and method capable of automatically and smoothly changing speed according to the position of the material on the conveyor line, and integrating intelligent status monitoring and active safety protection functions. Background Technology

[0002] In modern industrial production lines such as electronics, food, pharmaceuticals, and chemicals, the stability, efficiency, and safety of material conveying systems directly affect the smoothness of the entire production process and product quality. Chain conveyors, due to their robust structure and high load-bearing capacity, have become key equipment for achieving linear material transport in production lines.

[0003] However, traditional chain conveyors are typically driven by a single-speed motor, making variable-speed conveying impossible. When conveying materials requiring precise positioning or those sensitive to inertia (such as glass substrates, bottled liquids, and precision components), sudden acceleration changes during start-up and shutdown can generate significant inertial impacts, easily causing materials to slide, tip over, or collide with each other on the conveyor base, resulting in product damage or even production interruption. To address this issue, existing technologies often employ servo motors paired with precision control systems, using programming to achieve "S-shaped" or trapezoidal speed curves. However, this approach relies on controlling a single drive motor. When multiple materials are on the conveyor line, all materials must follow the same speed command, making it impossible to provide independent speed curves tailored to materials at different positions on the line, resulting in extremely poor flexibility.

[0004] Furthermore, most traditional conveying equipment only has basic limit protection functions and lacks effective monitoring of the conveying process. The system cannot know the actual speed of the conveyor base plate, whether slippage has occurred, or whether there are abnormal conditions such as jamming in real time. This makes equipment operation and maintenance rely on manual inspection, resulting in delayed fault detection, inability to achieve predictive maintenance, and difficulty in quickly locating the cause after a fault occurs, affecting production efficiency. At the same time, in automated production lines, especially at stations such as the discharge port, if the previous material is not removed in time and the next material has arrived, traditional conveyors lack effective anti-crushing detection mechanisms. This can easily lead to collisions and crushing of the two materials at the discharge port, which can not only damage the materials and equipment but also potentially cause safety accidents. Summary of the Invention

[0005] The purpose of this invention is to provide an intelligent chain-type smooth variable speed conveying system and a safety control method to solve the above-mentioned problems existing in the prior art.

[0006] The application is as follows: In a first aspect, the present invention provides an intelligent chain-type smooth variable speed conveying system, comprising: Material conveyor frame; At least one set of conveying modules is fixedly installed on the frame of the material conveyor; And a conveyor base plate for carrying materials is placed directly on the conveyor module; The conveying module includes a conveying module frame, a drive unit, and a drive shaft and at least three driven shafts arranged sequentially on the conveying module frame along the conveying direction. The drive unit is connected to the drive shaft to drive its rotation. A double-row sprocket is fixedly installed on the drive shaft and each of the driven shafts, and an independent chain is sleeved between every two adjacent double-row sprockets in the conveying direction for power transmission. Rollers are fixedly installed on the drive shaft and each of the driven shafts, and the conveying base plate is supported on all the rollers. Along the conveying direction, the number of teeth of the double-row sprockets on each driven shaft is set according to a preset speed change curve; so that when the conveying base plate moves, its linear velocity can automatically and continuously change according to the number of teeth of the sprockets on the driven shaft at its position.

[0007] Furthermore, the drive unit includes a motor reducer, which is fixedly mounted on the conveyor module frame via a torque arm; both the drive shaft and the driven shaft are mounted on the conveyor module frame via connecting bearings; guide wheels for preventing the conveyor base plate from deviating are installed on both sides of the conveyor module frame.

[0008] Furthermore, the velocity change curve is a smooth and continuous curve, and the absolute value of acceleration in the feed and discharge areas of the conveyor is less than the absolute value of acceleration in the middle area of ​​the conveyor.

[0009] Furthermore, along the conveying direction, the number of teeth on the double-row sprockets on the driven shaft increases or decreases monotonically, and the difference in the number of teeth between two adjacent double-row sprockets on the driven shaft is 1 to 3 teeth, so as to ensure the continuity and smoothness of speed changes and effectively eliminate rigid impact.

[0010] Furthermore, the conveying module frame is equipped with a photoelectric sensing system, which includes a first type of photoelectric switch installed at the start and end of the conveying path, and a second type of photoelectric switch installed in the key speed-changing section of the conveying path. The first type of photoelectric switch is used to monitor the placement and removal of the conveying base plate to realize system flow management, and the second type of photoelectric switch is used to detect the passing speed of the conveying base plate to perform operating status verification.

[0011] Furthermore, the conveying module frame is provided with an associated anti-pinch limit switch group in the discharge port area. The anti-pinch limit switch group includes a first limit switch for detecting the occupancy status of the discharge port and a second limit switch located upstream of it for detecting the approach status of the subsequent conveying base plate. When the first limit switch and the second limit switch are triggered simultaneously, the system executes an alarm and a stop command.

[0012] Furthermore, the system also includes a control system configured to: calculate the actual operating speed of the conveying base plate based on the signal of the second type of photoelectric switch, compare it with the theoretical speed curve set based on the number of teeth, and execute a fault alarm when the speed deviation exceeds the allowable range.

[0013] Furthermore, the distance between the second limit switch and the first limit switch is greater than the length of one of the conveying base plates.

[0014] Secondly, the present invention provides a safety control method for an intelligent chain-type smooth variable speed conveying system, the method comprising: Smooth speed control steps: The double-row sprocket set with the number of teeth changing according to the preset speed curve provides different drive linear speeds to the conveyor base plates located at different positions on the conveyor line; so that the individual conveyor base plates undergo an automatic smooth acceleration and deceleration process determined by the mechanical structure during the process of moving from the inlet to the outlet. Status monitoring steps: Monitor the position and speed status of the conveyor base plate through the photoelectric sensing system; Safety protection steps: The status of the discharge port is monitored by the anti-extrusion limit switch group. When the first limit switch and the second limit switch are triggered at the same time, an emergency stop is executed.

[0015] Compared with the prior art, the embodiments of the present invention achieve the following beneficial effects: This invention hardware-encapsulates a preset smooth speed curve through a "gradually varying sprocket tooth count" mechanical structure. The speed change of the conveyor base plate is determined by the number of sprocket teeth at its position, achieving continuous, stepless, and smooth acceleration and deceleration. This solves the problem of huge inertial impacts caused by sudden acceleration changes during start-stop in traditional chain conveyors, effectively preventing material slippage, overturning, or collisions on the conveyor base plate. It is particularly suitable for conveying high-value materials sensitive to inertial impacts, such as electronic components, glass substrates, and bottled liquids. Simultaneously, by implementing "intrinsic speed regulation" tied to position, it supports independent parallel conveying of multiple materials. Because the speed characteristics are fixed in the hardware structure, when multiple conveyor base plates are on the conveyor line simultaneously, each base plate can automatically obtain its corresponding preset speed based on its real-time position.

[0016] This invention can monitor the actual operating speed of the conveyor base plate in real time and compare it with the theoretical speed curve of the sprocket. Once a speed deviation exceeds the threshold (such as slippage or overload), an alarm can be triggered immediately, realizing the transformation from "post-fault maintenance" to "pre-fault warning" and greatly reducing unplanned downtime.

[0017] This invention provides an active safety protection mechanism that effectively avoids equipment damage and safety accidents. Through the coordinated logic judgment of the first and second limit switches, an alarm can be immediately triggered and the machine can be shut down in case of a risk of blockage at the discharge port, effectively preventing equipment damage and production interruption caused by material compression and collision. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the intelligent chain-type smooth variable speed conveying system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the conveying module provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the internal structure of the conveying module frame provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the driving shaft and the driven shaft provided in an embodiment of the present invention; Among them, 1-material conveyor frame; 2-conveying module; 3-conveying base plate; 21-conveying module frame; 22-motor reducer; 23-torsion arm; 24-limit switch mounting base; 25-limit switch; 26-driven shaft; 27-drive shaft; 28-guide wheel; 29-photoelectric switch; 271-chain; 272-connecting bearing; 273-double row sprocket; 274-roller. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments given herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] It should be noted that many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may have other embodiments, and therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0021] See attached document Figure 1-4 As shown, the intelligent chain-type smooth variable speed conveying system provided in this embodiment mainly includes a material conveyor frame 1, a conveying module 2, and a conveying base plate 3; The material conveyor frame 1, serving as the supporting foundation for the entire equipment, is welded from structural steel and possesses sufficient rigidity and stability. At least one set of conveying modules 2 is bolted and fixedly installed onto the material conveyor frame 1. The conveying base plate 3 is placed directly on the conveying module 2 and is used to support the material. It has a rectangular plate structure, and the bottom surface must be kept flat to facilitate frictional transmission.

[0022] The drive unit employs a motor reducer 22, which is securely connected to a protruding structure on the side of the conveyor module frame 21 via a torque arm 23, effectively counteracting the reaction torque during operation. The output end of the motor reducer 22 is connected to one side of the drive shaft 27 via a coupling. The drive shaft 27 and at least three driven shafts 26 are arranged sequentially along the conveying direction, and they are all mounted on the inner sides of the conveyor module frame 21 via bearing seats 272 on both sides, ensuring the parallelism and stable support of all shafts.

[0023] Double-row sprockets 273 are fixedly mounted on the drive shaft 27 and each driven shaft 26. All double-row sprockets 273 are located on the same side, and an independent chain 271 is sleeved between every two adjacent double-row sprockets 273 in the conveying direction, thereby transmitting the rotation of the motor reducer 22 from the drive shaft 27 to all driven shafts 26 to ensure synchronous rotation.

[0024] The hardware implementation of the speed curve and the configuration of the number of sprocket teeth are used to achieve the core smooth speed change function. Along the conveying direction, the number of teeth of the double-row sprockets 273 on each driven shaft 26 is set according to the preset smooth speed curve.

[0025] The mathematical model for the speed smoothing curve uses a piecewise function to define the speed curve (vx curve) for the entire conveying process, ensuring that the absolute value of acceleration in the infeed and discharge zones is less than that in the intermediate zone, thereby effectively reducing start-stop impact. Assuming the total conveying length is L, it can be divided into an acceleration section (0-L1), a high-speed section (L1-L2), and a deceleration section (L2-L).

[0026] The acceleration phase (0 ≤ x < L1) employs a sinusoidal acceleration model, resulting in a smooth velocity increase. Therefore, the acceleration... and speed The expressions are as follows:

[0027] in To preset the maximum acceleration, This is the non-zero initial velocity at the feed inlet (x=0), a value set according to the actual application scenario. It is a very small velocity, such as 0.02~0.1m / s. This velocity is sufficient to ensure a smooth start-up and material transfer, avoiding displacement, tipping, or collision of materials at the transfer point due to sudden velocity changes, while not affecting the subsequent acceleration process. In the high-speed section (L1≤x≤L2), the speed remains constant. ; The deceleration phase (L2≤x≤L) adopts a sinusoidal deceleration model symmetrical to the acceleration phase. Therefore, the acceleration... and speed The expressions are as follows:

[0028] The curve shows continuous acceleration at the connection point without abrupt changes, thus theoretically eliminating rigid impact.

[0029] Assuming the rotational speed of the drive shaft remains constant, the linear velocity of the conveyor base plate at a certain point is inversely proportional to the number of teeth on the sprockets on the drive shaft below that point. Let the output speed of the motor reducer 22 be N (rpm), and the number of teeth on the double-row sprockets 273 on the drive shaft 27 be... For any driven shaft 26, let the number of teeth on its sprocket be... Its rotational speed satisfy:

[0030] The linear velocity of the conveyor base plate at that point (That is, the linear velocity of roller 274) is:

[0031] Where D is the diameter of the roller.

[0032] therefore, .

[0033] Determine the minimum speed required at the feed inlet based on process requirements. and the maximum speed of the high-speed section .

[0034] Corresponding to Number of sprocket teeth Maximum should be:

[0035] Corresponding to Number of sprocket teeth Minimum should be:

[0036] The calculation result should be the closest integer value.

[0037] Discretized speed curve and tooth number allocation: The continuous speed curve is distributed along the conveying direction at the installation position of each driven shaft 26. Sampling is performed to obtain the target velocity value at that point. According to the formula

[0038] Calculate the number of sprocket teeth required for each driven shaft 26 and round down.

[0039] Check the difference in the number of sprocket teeth between adjacent driven shafts 26 To ensure the continuity and smoothness of speed changes and effectively eliminate rigid impacts, The number of teeth should be controlled between 1 and 3. If this is not met, the sampling points or the number of teeth on the speed curve need to be fine-tuned.

[0040] Two rollers 274 are fixedly installed on each of the drive shaft 27 and each driven shaft 26. The conveyor base plate 3 is directly supported on all these rollers 274 and is driven to move in a straight line by friction. To ensure accurate movement trajectory, guide wheels 28 are also installed on both sides of the conveyor module frame 21. These guide wheels 28 cooperate with the sides of the conveyor base plate 3 to effectively prevent deviation.

[0041] On both sides of the conveyor module frame 21 along the conveying direction, photoelectric switches 29, serving as first-type photoelectric switches, are fixedly installed to monitor the insertion (inlet) and exit (outlet) of the conveyor base plate 3, achieving basic system flow management. To achieve status monitoring, at least one pair of photoelectric switches 29, serving as second-type photoelectric switches, are installed laterally in key speed-changing sections of the conveying path (such as the main acceleration section and the main deceleration section). The distance between these switches... The exact location is known, and its installation position on the conveying path has been pre-marked, so that the theoretical speed corresponding to the midpoint of the interval is a known value, which is used to detect the passing speed of the conveying base plate 3.

[0042] In the discharge port area, two limit switches 25 are installed via limit switch mounting brackets 24, forming an anti-pinch limit switch group. The first limit switch is installed at the precise stop position of the discharge port to detect its occupancy status. The second limit switch is installed upstream of LS1, with the distance between them strictly greater than the length of a conveyor base plate 3, to detect the approach of subsequent conveyor base plates. All sensor signal lines are connected to the system's central controller.

[0043] The security control method described in this invention, based on the aforementioned system hardware, is implemented by a central controller executing a pre-programmed program, and mainly includes the following steps: S1. Smooth Speed ​​Change Control Process: After the equipment is powered on, the control system performs a self-check. Subsequently, the motor reducer 22 is started and set to operate at a constant output speed. This is the basis for the smooth operation of the entire system. The output torque of the motor reducer 22 is transmitted to the drive shaft 27 through its output end. The rotational motion of the drive shaft 27 is synchronously transmitted to all driven shafts 26 through the double-row sprockets 273 and chain 271 fixedly mounted on it.

[0044] Feeding and Start-up: When a conveyor base plate 3 is placed at the feed inlet, the conveyor base plate 3 instantly receives an initial driving force and begins to move at a preset minimum speed. The slow and smooth start effectively eliminates the shock that may occur when starting from absolute rest.

[0045] Automatic acceleration process: As the conveyor base plate 3 moves in the conveying direction, its bottom support point gradually enters the area of ​​the roller 274 driven by the sprocket with fewer teeth. The speed of the conveyor base plate 3 is automatically and smoothly increased.

[0046] High-speed operation phase: When the conveyor base plate 3 reaches the middle section of the conveyor path, the roller 274 driven by the sprocket with the fewest teeth underneath it reaches its maximum speed. And transport them at a constant speed.

[0047] Smooth deceleration and stopping: As it approaches the discharge port, the conveyor base plate 3 enters the area driven by a sprocket with an increasing number of teeth. This automatically and smoothly slows down the speed of the conveyor base plate 3, eventually bringing it to a smooth stop at the discharge station.

[0048] The system enables independent, parallel conveying of multiple conveyor base plates 3, with each plate's speed independent of the others. The instantaneous speed of each conveyor base plate 3 depends solely on its current position on the conveying path, and is completely independent of whether other base plates are present at that position or their operating status. The system does not require individual adjustment of the motor speed for any single base plate.

[0049] S2. Status Monitoring and Self-Diagnosis Process: When the starting photoelectric switch 29 is triggered, the internal counter of the controller increments by one, indicating that a new baseboard has entered the system; when the signal from the ending photoelectric switch 29 disappears, the counter decrements by one. This mechanism manages the number of baseboards on the line and prevents overload.

[0050] When the conveyor base plate 3 sequentially triggers the two second-type photoelectric switches 29 in the key speed change section, the controller records timestamps t1 and t2 and calculates the average speed. .

[0051] The controller will The theoretical velocity value corresponding to this position (Determined by the sprocket tooth count curve) Compare.

[0052] Normal state: The deviation is within the preset allowable range (e.g., If the percentage is within ±5%, the system is deemed to be in good operating condition and will continue to operate normally.

[0053] Overspeed fault This situation usually indicates an abnormality in the transmission system. Possible causes include slippage due to wear and loosening of chain 271 (causing the drive shaft to spin freely, causing the base plate to lurch forward due to inertia), or a failure in the connection between sprocket 273 and shafts (26, 27). The system will immediately trigger a medium-level alarm (such as a yellow warning light) and can automatically reduce the speed of motor 22 according to a preset strategy to protect the equipment.

[0054] Low speed / jamming fault This situation is more urgent and usually indicates a disruption in the conveying process. Possible causes include material overloading, mechanical interference between the conveyor base plate 3 and the guide rollers 28 or the frame, or a damaged bearing 272 causing a sharp increase in rotational resistance. The system will immediately trigger a high-level alarm (such as a red warning light and a buzzer) and execute an emergency stop command to stop the motor 22, preventing equipment damage or escalation of the accident.

[0055] S3. Safety protection process: The controller monitors the status of the anti-pinch limit switch group in real time.

[0056] Normal state: The bottom plate of the discharge port is removed, LS1 is not triggered, and the subsequent bottom plate can approach and stop normally.

[0057] Risk status: If LS1 has been triggered (the discharge port is occupied by a bottom plate), and LS2 has also been triggered (the subsequent bottom plate has approached the danger distance), the controller will immediately determine that there is a risk of crushing.

[0058] Emergency Response: In the instant that a risky situation is determined, the controller executes the highest priority interrupt procedure, immediately stops the operation of the motor reducer 22, and issues a rapid alarm sound, thereby effectively preventing equipment collision and material damage.

[0059] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0060] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. Any of the claimed embodiments can be used in any combination.

Claims

1. An intelligent chain-type smooth variable speed conveying system, characterized in that, include: Material conveyor frame; At least one set of conveying modules is fixedly installed on the frame of the material conveyor; And a conveyor base plate for carrying materials is placed directly on the conveyor module; The conveying module includes a conveying module frame, a drive unit, and a drive shaft and at least three driven shafts arranged sequentially on the conveying module frame along the conveying direction. The drive unit is connected to the drive shaft to drive its rotation. A double-row sprocket is fixedly installed on the drive shaft and each of the driven shafts, and an independent chain is sleeved between every two adjacent double-row sprockets in the conveying direction for power transmission. Rollers are fixedly installed on the drive shaft and each of the driven shafts, and the conveying base plate is supported on all the rollers. Along the conveying direction, the number of teeth of the double-row sprockets on each driven shaft is set according to a preset speed change curve; so that when the conveying base plate moves, its linear velocity can automatically and continuously change according to the number of teeth of the sprockets on the driven shaft at its position.

2. The intelligent chain-type smooth variable speed conveying system according to claim 1, characterized in that: The drive unit includes a motor reducer, which is fixedly mounted on the conveyor module frame via a torque arm; both the drive shaft and the driven shaft are mounted on the conveyor module frame via connecting bearings; guide wheels are installed on both sides of the conveyor module frame to prevent the conveyor base plate from deviating.

3. The intelligent chain-type smooth variable speed conveying system according to claim 1, characterized in that: The velocity change curve is a smooth and continuous curve, and the absolute value of acceleration in the feed and discharge areas of the conveyor is less than the absolute value of acceleration in the middle area of ​​the conveyor.

4. The intelligent chain-type smooth variable speed conveying system according to claim 1, characterized in that: Along the conveying direction, the number of teeth on the double-row sprockets on the driven shaft increases or decreases monotonically, and the difference in the number of teeth between two adjacent double-row sprockets on the driven shaft is 1 to 3 teeth, so as to ensure the continuity and smoothness of speed change and effectively eliminate rigid impact.

5. The intelligent chain-type smooth variable speed conveying system according to claim 1, characterized in that: The conveying module frame is equipped with a photoelectric sensing system, which includes a first type of photoelectric switch installed at the start and end of the conveying path, and a second type of photoelectric switch installed in the key speed-changing section of the conveying path. The first type of photoelectric switch is used to monitor the placement and removal of the conveying base plate to realize system flow management, and the second type of photoelectric switch is used to detect the passing speed of the conveying base plate to perform operation status verification.

6. The intelligent chain-type smooth variable speed conveying system according to claim 1, characterized in that: The conveying module frame is equipped with an anti-pinch limit switch group in the discharge port area. The anti-pinch limit switch group includes a first limit switch for detecting the occupancy status of the discharge port and a second limit switch located upstream of it for detecting the approach status of the subsequent conveying base plate. When the first limit switch and the second limit switch are triggered simultaneously, the system executes an alarm and a stop command.

7. The intelligent chain-type smooth speed-changing conveying system according to claim 5, characterized in that: The system also includes a control system configured to: calculate the actual operating speed of the conveying base plate based on the signal of the second type of photoelectric switch, compare it with the theoretical speed curve set based on the number of teeth, and execute a fault alarm when the speed deviation exceeds the allowable range.

8. The intelligent chain-type smooth variable speed conveying system according to claim 6, characterized in that: The distance between the second limit switch and the first limit switch is greater than the length of one of the conveying base plates.

9. A safety control method based on the intelligent chain-type smooth variable speed conveying system according to any one of claims 1 to 8, characterized in that, The method includes: Smooth speed control steps: The double-row sprocket set with the number of teeth changing according to the preset speed curve provides different drive linear speeds to the conveyor base plates located at different positions on the conveyor line; so that the individual conveyor base plates undergo an automatic smooth acceleration and deceleration process determined by the mechanical structure during the process of moving from the inlet to the outlet. Status monitoring steps: Monitor the position and speed status of the conveyor base plate through the photoelectric sensing system; Safety protection steps: The status of the discharge port is monitored by the anti-extrusion limit switch group. When the first limit switch and the second limit switch are triggered at the same time, an emergency stop is executed.

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