Rear-end collision prevention circuit of tray, tray control device and tray system of reflow oven

Abstract

The utility model discloses a rear-end collision prevention circuit of a tray, a tray control device and a tray system of a reflow oven, and relates to the field of circuits, a tray detection module is arranged at a discharge port of the reflow oven and can detect whether the tray stays at the discharge port, and when the discharge port is shielded by the tray, a control switch is switched off, a control loop of a push hook is disconnected, and the tray control device is switched off. The pushing hook cannot work normally, the next tray cannot be continuously pushed to the chain of the feeding port, and collision between the next tray and the tray which is blocked at the discharging port currently is avoided; and when the discharge port is not shielded by the tray, the control switch is switched on, and the control loop of the push hook normally controls the push hook to convey the next tray. Whether the trays slip or not is determined by detecting shielding of the trays at the discharging port, collision between the trays is avoided by cutting off or conducting a control loop of the push hook, and the safety and reliability of the whole tray conveying process of the reflow oven are improved.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and particularly to an anti-rear-end collision circuit for a tray, a tray control device and a tray system of a reflow oven. Background Art

[0002] In the manufacturing process of electronic component chip soldering, it is often necessary to use a reflow oven to perform heat treatment on the solder used in chip soldering. For example, after the flip-chip soldering of the chip is completed, it is necessary to use a reflow oven to perform reflow on the solder balls after soldering. The chip is placed on a frame. And since the current reflow oven is a vacuum oven, the frame cannot directly enter the reflow oven alone and must rely on a tray as a carrier to realize the transfer of the chip and the frame during the reflow process. A push hook is arranged at the transfer part of the reflow oven and is pushed forward step by step by the push hook. Finally, the tray is pushed from the feeding position to the chain of the discharge port conveyor belt, and then the tray is transferred from the discharge port conveyor belt area to the next working area by relying on the friction force between the tray and the chain. During the transfer process, the tray must move smoothly while being pushed by the push hook. Therefore, the surface of the tray is set to be relatively smooth, which will reduce the friction force between it and the chain, and it may occur that the previous tray slips and is not transferred away, while the next tray is pushed out by the push hook, resulting in a collision between the two trays. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an anti-rear-end collision circuit for a tray, a tray control device and a tray system of a reflow oven, which can determine whether the tray slips by detecting the occlusion of the tray at the discharge port, and avoid the collision between trays by cutting off or conducting the control loop of the push hook, so as to improve the safety and reliability of the whole process of transferring the tray by the reflow oven.

[0004] To solve the above technical problems, the utility model provides an anti-rear-end collision circuit for a tray, including:

[0005] A tray detection module arranged at the discharge port of the reflow oven, which is used to detect whether there is a tray staying at the discharge port of the reflow oven and output a corresponding level signal according to the detection result;

[0006] A control switch connected in series in the control loop of the push hook of the reflow oven, with the control end connected to the output end of the tray detection module, which is used to conduct or cut off based on the level signal output by the tray detection module.

[0007] Optionally, the control switch is a relay;

[0008] The relay includes a coil and a normally closed contact. The coil is connected to the output terminal of the tray detection module, and the normally closed contact is connected in series in the control circuit of the pusher hook of the reflow oven. When there is a tray blocking at the discharge port of the reflow oven, the coil is energized; when there is no tray blocking at the discharge port of the reflow oven, the coil is de-energized.

[0009] Optionally, it further includes:

[0010] A prompting module, connected in parallel across the two ends of the coil of the relay, and used to perform a prompting operation when the coil is energized.

[0011] Optionally, it further includes:

[0012] A power supply module, with its input terminal connected to the AC mains and its output terminal connected to the power supply terminal of the tray detection module, and used to convert the AC mains into the DC power supply required by the tray detection module.

[0013] Optionally, the power supply module includes:

[0014] A transformer, with the first end of the primary winding connected to the live wire of the AC mains and the second end connected to the neutral wire of the AC mains;

[0015] A rectifier bridge, with its first input terminal connected to the first end of the secondary winding of the transformer and its second input terminal connected to the second end of the secondary winding of the transformer;

[0016] A first capacitor, with its first end connected to the first output terminal of the rectifier bridge and serving as the first output terminal of the power supply module, and its second end connected to the second output terminal of the rectifier bridge and serving as the second output terminal of the power supply module.

[0017] Optionally, the power supply module further includes:

[0018] A second capacitor;

[0019] A voltage regulator, with its input terminal connected respectively to the first end of the first capacitor, the first end of the second capacitor, and the first output terminal of the rectifier bridge;

[0020] A third capacitor, with its first end connected to the output terminal of the voltage regulator and serving as the first output terminal of the power supply module, and its second end connected respectively to the second end of the second capacitor, the second end of the first capacitor, and the second output terminal of the rectifier bridge and serving as the second output terminal of the power supply module.

[0021] Optionally, the power supply module further includes:

[0022] A diode, with its anode connected to the output terminal of the voltage regulator and the first terminal of the third capacitor respectively, and its cathode connected to the second terminal of the third capacitor, the second terminal of the second capacitor, the second terminal of the first capacitor, and the second output terminal of the rectifier bridge respectively.

[0023] Optionally, the tray detection module includes:

[0024] A first resistor, with its first terminal connected to a DC power supply;

[0025] An emitting diode disposed at the discharge port of the reflow oven, with its first terminal connected to the second terminal of the first resistor and its second terminal grounded, for emitting an optical signal;

[0026] A receiving triode disposed at the discharge port of the reflow oven, which is turned on when receiving the reflected signal of the optical signal and turned off when not receiving the reflected signal of the optical signal;

[0027] An inverter, with its output terminal serving as the output terminal of the tray detection module;

[0028] An inductive switch, with its first terminal connected to the input terminal of the inverter, the first terminal of the first resistor, and the first terminal of the receiving triode respectively, its control terminal connected to the second terminal of the receiving triode, and its second terminal grounded; it is turned on when the receiving triode is turned on and turned off when the receiving triode is turned off.

[0029] Optionally, the tray detection module further includes:

[0030] A second resistor, with its first terminal connected to the first terminal of the receiving triode and the first terminal of the first resistor respectively, and its second terminal connected to the input terminal of the inverter and the first terminal of the inductive switch respectively;

[0031] A third resistor, with its first terminal grounded;

[0032] A fourth resistor, with its first terminal connected to the second terminal of the third resistor and the second terminal of the receiving triode respectively, and its second terminal connected to the control terminal of the inductive switch.

[0033] Optionally, the tray detection module further includes:

[0034] A fourth capacitor, with its first terminal grounded and its second terminal connected to the output terminal of the inverter.

[0035] To solve the above technical problems, the present utility model further provides a tray control device, which includes a controller and the anti-rear-end collision circuit of the tray as described above.

[0036] To solve the above technical problems, the present utility model further provides a tray system for a reflow oven, which includes the tray control device as described above and a plurality of trays.

[0037] The utility model provides an anti-rear-end collision circuit for a tray, a tray control device and a tray system of a reflow furnace, which are applied to the reflow furnace and include a tray detection module and a control switch. The tray detection module is arranged at the discharge port of the reflow furnace and can detect whether there is a tray staying at the discharge port. The control switch receives a corresponding level signal from the output end of the tray detection module. When there is a tray blocking at the discharge port, the control switch is turned off, and the control circuit of the push hook is disconnected, so that the push hook cannot work normally under control and cannot continue to push the next tray onto the chain at the discharge port, avoiding the collision between the next tray and the tray blocking at the discharge port currently; when there is no tray blocking at the discharge port, the control switch is turned on, and the control circuit of the push hook normally controls the push hook to transfer the next tray. By detecting the tray blocking at the discharge port to determine whether the tray slips, and by cutting off or conducting the control circuit of the push hook to avoid the collision between trays, the safety and reliability of the whole process of transporting trays in the reflow furnace are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the prior art and the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0039] Figure 1 It is a schematic structural diagram of an anti-rear-end collision circuit for a tray provided by the present utility model;

[0040] Figure 2 It is a schematic diagram of the action process of a tray in a reflow furnace provided by the present utility model;

[0041] Figure 3 It is a schematic structural diagram of another anti-rear-end collision circuit for a tray provided by the present utility model;

[0042] Figure 4 It is a schematic structural diagram of a power supply module provided by the present utility model;

[0043] Figure 5 It is a schematic structural diagram of a tray detection module provided by the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The core of the present utility model is to provide an anti-rear-end collision circuit for a tray, a tray control device and a tray system of a reflow furnace. By detecting the tray blocking at the discharge port to determine whether the tray slips, and by cutting off or conducting the control circuit of the push hook to avoid the collision between trays, the safety and reliability of the whole process of transporting trays in the reflow furnace are improved.

[0045] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0046] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of an anti-rear-end collision circuit for a tray provided by the present utility model; please refer to Figure 2 , Figure 2 which is a schematic diagram of the operation process of a tray in a reflow oven; to solve the above technical problems, the present utility model provides an anti-rear-end collision circuit for a tray, including:

[0047] A tray detection module 1 arranged at the discharge port of the reflow oven, which is used to detect whether there is a tray staying at the discharge port of the reflow oven and output a corresponding level signal according to the detection result;

[0048] A control switch K1 connected in series in the control circuit of the pusher hook of the reflow oven, with its control end connected to the output end of the tray detection module 1, which is used to conduct or cut off based on the level signal output by the tray detection module 1.

[0049] It should be noted that in order to achieve a process-based technological process, a reflow oven is equipped with a drive chain and a pusher hook to drive the chips and frames that need to be reflow soldered, so as to realize the transfer of the chips and their frames. The chips and their frames are placed in trays for convenient transfer. Taking the example of using solder for chips, before the solder melts, it is solid. At this time, there is no adhesion between the chip and its corresponding frame. It is necessary to rely on the high-temperature reflow oven to melt the solid tin into water, and the bonding between the chip and the frame is realized during the melting process. After the melted tin water cools, the tin becomes a solid layer again, thus realizing the entire reflow soldering process; in this process, the solder cannot be directly melted, but needs to be heated step by step. One temperature corresponds to one temperature zone. The tray drives the chip and its frame to pass through multiple temperature zones in sequence for step-by-step heating, and finally reaches the highest temperature to melt, and then goes to the cooling zone for cooling. Therefore, multiple temperature zones and a cooling zone are set between the inlet and outlet of the reflow oven. The pusher hook will, according to a preset program, such as taking 32 seconds as one time cycle according to the set time, every 32 seconds, the pusher hook will push the tray one temperature zone towards the outlet. At the same time, a chain conveyor belt is set in the reflow oven, and each temperature zone and the last temperature zone are connected to the cooling zone through chain transmission. The chain conveyor belt drives the tray to pass through each temperature zone and the cooling zone in sequence. When the heating of the tray in the current temperature zone is completed, the pusher hook pushes the tray onto the chain, and the tray is conveyed to the next working area through the chain, and the process of the tray passing through multiple temperature zones and the final cooling zone in sequence is realized through the pusher hook and the chain.

[0050] It can be understood that in order to avoid the situation of collisions during the transfer of the trays in the reflow oven, in this application, a tray detection module 1 is set at the outlet of the reflow oven, and at the same time, a control switch K1 is set in series in the control circuit of the corresponding pusher hook. The tray detection module 1 added at the chain outlet is used to detect whether the tray stays. When the tray stays, the tray detection module 1 outputs a level signal to control the control switch K1 in series in the pusher hook control circuit to turn off, so as to control that no tray enters at the feeding position of the reflow oven. When the tray does not stay, the level signal output by the tray detection module 1 will control the control switch K1 to conduct, and the control circuit of the pusher hook works normally, and the pusher hook works normally under its control. The chain drives the fixed rod of the pusher hook. Every 32 seconds, the pusher hook will convey the tray one temperature zone towards the outlet. When the pusher hook pushes the tray onto the chain conveyor belt area, the pusher hook will return to the first temperature zone to pick up the next tray. If it encounters the situation that the tray stays detected at the outlet at this time, the pusher hook will not continue to move and will not push the next tray onto the chain, thus avoiding the collision between the next tray and the currently staying tray, and realizing the anti-rear-end collision function of the trays in the reflow oven.

[0051] It should be noted that the tray itself only serves to carry the chip and its frame. The specific implementation methods of the material, size, etc. of the tray itself are not particularly limited in this application; the specific types and implementation methods of the tray detection module 1 and the control switch K1 are not particularly limited in this application. The tray detection module 1 can be implemented by detection devices such as sensors, and the control switch K1 can be implemented by controllable switch devices such as relays and power electronic switches. The specific implementation method of the control loop of the push hook is not particularly limited in this application, and the setting method of the control switch K1 can also be adjusted according to the specific implementation of the control loop of the push hook, as long as it can achieve the control of whether the push hook works properly.

[0052] Furthermore, the specific number and setting position of the tray detection module 1 are not limited to the inlet of the reflow oven proposed in this application. This application does not make special limitations here and can be adjusted according to the specific setting methods of the chain and the push hook in the reflow oven; the chains between each temperature zone and the cooling zone in the reflow oven may be realized by multiple sub-chains respectively, and the push hooks may also be set with push hooks corresponding to each area one by one. At this time, the tray detection module 1 may include a plurality of tray detection sub-modules corresponding to each sub-chain and arranged at the outlets of each sub-chain, and control sub-switches corresponding to and connected to each tray detection sub-module are set at the same time. Each control sub-switch is set in the control sub-loop of the push hook corresponding to each sub-chain. For example, when there are two temperature zones and one cooling zone in the reflow oven, a first sub-chain is set between the inlet of the reflow oven and the first temperature zone, a first sub-push hook is set at the inlet, a second sub-chain is set between the first temperature zone and the second temperature zone, a second sub-push hook is set in the first temperature zone, a third sub-chain is set between the second temperature zone and the cooling zone, a third sub-push hook is set in the second temperature zone, a fourth sub-chain is set between the cooling zone and the outlet of the reflow oven, and a fourth sub-push hook is set in the cooling zone; at this time, tray detection sub-modules can be set at the outlets of the first sub-chain, the second sub-chain, the third sub-chain, and the fourth sub-chain respectively, and control sub-switches corresponding to the first sub-push hook, the second sub-push hook, the third sub-push hook, and the fourth sub-push hook are set at the same time to ensure that the tray will not collide due to slipping when coming out of each area.

[0053] Specifically, the tray detection module 1 can be implemented by a light reflection sensor, and the control switch K1 can be implemented by a relay. An additional light reflection sensor is added at the discharge port of the reflow oven. If there is no tray slippage, there will be no tray staying at the discharge port. If there is tray slippage at the discharge port, the light generated by the light reflection sensor will be blocked by the tray and reflected back to the light reflection sensor. At this time, the output pin of the light reflection sensor will output a 24V power supply to the positive pole of the buzzer and the positive pole of the relay. At the same time, since the negative poles of the buzzer and the relay are fixedly connected to the negative pole of the power supply, after the positive pole obtains a 24V power supply, the buzzer alarms, and at the same time, the coil of the relay works to change the normally closed contact connected between pins 1 and 2 to open. Pins 1 and 2 are connected to the feeding signal of the reflow oven. Only when pins 1 and 2 are short-circuited can the feeding signal be normally output, and the reflow oven will feed a new tray under the action of the pusher hook. After the relay works, it will disconnect pins 1 and 2, so the reflow oven will no longer feed a new tray. At the same time, after the buzzer alarms, the operator can promptly remove the tray that is slipping at the discharge port. After removing the tray, the buzzer and the relay are disconnected from the 24V positive pole, the alarm is eliminated, the relay coil loses power, and pins 1 and 2 are re-conducted. The feeding signal of the reflow oven is restored, and the next new tray can be fed, and the normal operation resumes.

[0054] The present utility model provides an anti-rear-end collision circuit for trays, which is applied to a reflow oven and includes a tray detection module 1 and a control switch K1. The tray detection module 1 is arranged at the discharge port of the reflow oven and can detect whether there is a tray staying at the discharge port. The control switch K1 will receive a corresponding level signal from the output end of the tray detection module 1. When there is a tray blocking at the discharge port, the control switch K1 is turned off, disconnecting the control circuit of the pusher hook, so that the pusher hook cannot be controlled to work normally and cannot continue to push the next tray onto the chain at the feeding port, avoiding the collision between the next tray and the tray currently blocking at the discharge port. When there is no tray blocking at the discharge port, the control switch K1 is turned on, and the control circuit of the pusher hook normally controls the pusher hook to convey the next tray. By detecting the tray blocking at the discharge port to determine whether the tray has slipped, and by cutting off or turning on the control circuit of the pusher hook to avoid the collision between trays, the safety and reliability of the entire process of conveying trays by the reflow oven are improved.

[0055] Based on the above embodiments:

[0056] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of another anti-rear-end collision circuit for trays provided by the present utility model; As an optional embodiment, the control switch K1 is a relay;

[0057] The relay includes a coil and a normally closed contact. The coil is connected to the output terminal of the tray detection module 1, and the normally closed contact is connected in series in the control circuit of the pusher hook of the reflow oven. When there is a tray blocking at the discharge port of the reflow oven, the coil is energized; when there is no tray blocking at the discharge port of the reflow oven, the coil is de-energized.

[0058] It is not difficult to understand that the control switch K1 can be implemented by a relay. The coil of the relay is used to receive the detection result of the tray detection module 1, and the normally closed contact is arranged in the control circuit of the pusher hook. When the tray is pushed onto the chain by the pusher hook of the reflow oven, if the tray is not normally conveyed away by the chain, the tray detection module 1 will detect that the tray has an abnormal slip and stay situation. If it exists, a high-level signal of 24V is output to the positive pole of the coil of the relay. The negative pole of the coil of the relay is fixedly connected to the negative pole of the power supply. Therefore, at this time, the coil of the relay is energized and works, the normally closed contact is disconnected, and the control circuit of the pusher hook cannot normally output a control signal, and the pusher hook stops working. The reflow oven will not feed the next tray under the action of the pusher hook; if the tray does not have an abnormal slip and stay situation, the tray detection module 1 can output a low-level signal to the positive pole of the coil of the relay, and there is no power supply voltage between the positive and negative poles of the coil, maintaining a de-energized and non-working state, and the normally closed contact remains closed, and the pusher hook works normally and normally pushes the next tray into the reflow oven. As Figure 3 shown, parallel diodes can be further arranged at both ends of the coil to improve the accuracy and reliability of the coil during operation.

[0059] Specifically, the relay can accurately implement the function of the control switch K1 to act based on the detection result of the tray detection module 1, effectively realize the control of the working process of the pusher hook. At the same time, the relay can realize remote control, avoiding the situation that it is difficult to control due to the too far setting positions of the tray detection module 1 and the control circuit of the pusher hook. The implementation method is flexible and the applicable range is wide.

[0060] As an optional embodiment, it further includes:

[0061] A prompting module BZ, connected in parallel at both ends of the coil of the relay, is used to perform a prompting operation when the coil is energized.

[0062] It is not difficult to understand that a prompting module BZ can be further added to prompt and alarm whether the tray has an abnormal stay situation, which is convenient for the operator to obtain the abnormal situation of the tray in time. The specific type and setting method of the prompting module BZ are not particularly limited in this application. As Figure 3As shown in the figure, the prompting module BZ can be implemented by adding a delay buzzer for alarming. Considering that the reflow oven itself has a feeding signal, and this signal is a short - circuit signal, a normally - closed relay can be connected in series on the signal line of this signal to control the feeding timing. At the same time, a delay buzzer is connected in parallel across the two ends of the relay coil to achieve the prompting alarm. If the tray has an abnormal slipping and staying situation, when the tray detection module 1 outputs a 24V power signal to the relay coil, it also outputs a 24V power signal to the delay buzzer. The buzzer starts to alarm after a 5 - second delay. After the operator hears the alarm, the tray can be manually removed. After the tray is removed, the alarm disappears, the relay coil is powered off again, the feeding signal is connected, and the reflow oven can feed the tray again.

[0063] Specifically, the setting of the control switch K1 can be directly achieved by multiplexing the feeding signal of the reflow oven itself. At the same time, by setting the prompting module BZ, the abnormal situation of the tray can be visually and effectively informed to the operator, facilitating the operator to perform operations such as removing the tray in time to eliminate faults, and starting the normal working process of the reflow oven in time, improving the working efficiency of the entire circuit while ensuring safety.

[0064] Please refer to Figure 4 , Figure 4 is a schematic structural diagram of a power supply module provided by the present utility model; as an alternative embodiment, it further includes:

[0065] The power supply module, with its input end connected to the AC mains and its output end connected to the power supply end of the tray detection module 1, is used to convert the AC mains into the DC power supply VCC required by the tray detection module 1.

[0066] It is not difficult to understand that considering that the tray detection module 1 generally needs the DC power supply VCC for power supply during the working process and may also need the DC power supply VCC to control the control switch K1, a power supply module can be further added to the circuit to provide the DC power supply VCC required for the operation of the tray detection module 1. The specific type and implementation method of the power supply module are not particularly limited in this application. The specific value of the output DC power supply VCC can also be adjusted and set according to the actual application requirements of the tray detection module 1, which is not particularly limited in this application.

[0067] Specifically, in order to ensure the normal operation of the tray detection module 1 and the effective control of the control switch K1, a power supply module can be further added to the circuit to provide the DC power supply VCC required during the working process of the tray detection module 1, ensuring the normal implementation of the tray detection module 1 and the entire anti - rear - end collision circuit.

[0068] As an alternative embodiment, the power supply module includes:

[0069] A transformer T, the first end of the primary winding is connected to the live wire of the AC mains, and the second end is connected to the neutral wire of the AC mains;

[0070] A rectifier bridge BR, the first input terminal is connected to the first end of the secondary winding of the transformer T, and the second input terminal is connected to the second end of the secondary winding of the transformer T;

[0071] A first capacitor C1, the first end is connected to the first output terminal of the rectifier bridge BR and serves as the first output terminal of the power supply module, and the second end is connected to the second output terminal of the rectifier bridge BR and serves as the second output terminal of the power supply module.

[0072] It is not difficult to understand that the power supply module can directly use the AC mains to convert to obtain the DC power supply VCC required by the tray detection module 1. Therefore, a transformer T needs to be set in the power supply module to first step down the AC mains to a smaller AC voltage, and then use the rectifier bridge BR to convert the AC to DC. At the same time, a first capacitor C1 is set on the output side to filter the finally output DC power, improving the stability and accuracy of the finally output DC power. The specific types and implementation methods of the transformer T, the rectifier bridge BR, and the first capacitor C1 are not particularly limited in this application. For example, Figure 4 As shown, the rectifier bridge BR can be implemented by a circuit composed of diodes D1, D2, D3, and D4.

[0073] Specifically, the power supply module can specifically include a transformer T, a rectifier bridge BR, and a first capacitor C1, which first step down and then rectify the AC mains, effectively realizing the process of converting the AC mains into the DC power supply VCC. The entire circuit structure is simple and easy to implement, which is beneficial to the simple implementation of the entire anti-rear-end collision circuit.

[0074] As an optional embodiment, the power supply module further includes:

[0075] A second capacitor C2;

[0076] A low-dropout regulator LDO, the input terminal is respectively connected to the first end of the first capacitor C1, the first end of the second capacitor C2, and the first output terminal of the rectifier bridge BR;

[0077] A third capacitor C3, the first end is connected to the output terminal of the low-dropout regulator LDO and serves as the first output terminal of the power supply module, and the second end is respectively connected to the second end of the second capacitor C2, the second end of the first capacitor C1, and the second output terminal of the rectifier bridge BR and serves as the second output terminal of the power supply module.

[0078] It is not difficult to understand that the power supply module may further include a second capacitor C2, a low-dropout regulator (LDO), and a third capacitor C3. The second capacitor C2 and the third capacitor C3 can further play a filtering role to improve the accuracy and reliability of the finally output DC power supply VCC. The low-dropout regulator (LDO) can play a voltage regulation role to stabilize the converted DC power supply VCC at a preset regulated voltage value, ensuring that the finally output is a DC voltage of the voltage level required by the tray detection module 1. The specific types, implementation manners, parameter settings, etc. of the second capacitor C2, the low-dropout regulator (LDO), and the third capacitor C3 are not particularly limited in this application.

[0079] Specifically, the power supply module may further include a second capacitor C2, a low-dropout regulator (LDO), and a third capacitor C3 to implement a further voltage regulation and filtering process for the DC power supply VCC, improve the accuracy and reliability of the finally output DC power supply VCC. The entire circuit structure is simple and easy to implement, which is beneficial to the simple implementation of the entire anti-rear-end collision circuit.

[0080] As an optional embodiment, the power supply module further includes:

[0081] A diode D0, the anode of which is respectively connected to the output terminal of the low-dropout regulator (LDO) and the first terminal of the third capacitor C3, and the cathode of which is respectively connected to the second terminal of the third capacitor C3, the second terminal of the second capacitor C2, the second terminal of the first capacitor C1, and the second output terminal of the rectifier bridge BR.

[0082] It is not difficult to understand that a reversely connected diode D0 may be further provided in the power supply module. By utilizing the stable and reliable penetration characteristic of the reversely biased diode D0, the voltage regulation of the DC power supply VCC can be further realized, and at the same time, an overvoltage protection function can be achieved to further protect the circuit. The specific type and implementation manner of the diode D0 are not particularly limited in this application.

[0083] Specifically, a diode can be further added in the power supply module to play a role in voltage regulation and circuit protection, improve the stability and accuracy of the finally output DC power supply VCC, and ensure the safety and reliability of the entire power supply module. The diode has a simple structure, is easy to implement, has a low cost, and a small volume, which is beneficial to the simple implementation of the entire anti-rear-end collision circuit.

[0084] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of a tray detection module provided by the present utility model. As an optional embodiment, the tray detection module 1 includes:

[0085] A first resistor R1, the first terminal of which is connected to the DC power supply VCC;

[0086] The light-emitting diode Q1 is arranged at the discharge port of the reflow oven, with its first end connected to the second end of the first resistor R1 and its second end grounded, for emitting optical signals.

[0087] The receiving triode Q2 is arranged at the discharge port of the reflow oven, and is used to conduct when receiving the reflected signal of the optical signal and turn off when not receiving the reflected signal of the optical signal.

[0088] The inverter U0, with its output end serving as the output end of the tray detection module 1.

[0089] The inductive switch Q3, with its first end respectively connected to the input end of the inverter U0, the first end of the first resistor R1 and the first end of the receiving triode Q2, its control end connected to the second end of the receiving triode Q2, and its second end grounded; it is used to conduct when the receiving triode Q2 conducts and turn off when the receiving triode Q2 cuts off.

[0090] It can be understood that the tray detection module 1 can be specifically implemented by an optical reflection sensor. The optical reflection sensor specifically includes a light-emitting diode Q1 and a receiving triode Q2. The light-emitting diode Q1 emits an optical signal to the discharge port of the reflow oven. When there is an abnormally staying tray at the discharge port, the emitted light will be reflected back by the abnormally staying tray and reflected to the receiving triode Q2. When the receiving triode Q2 receives the reflected optical signal, it will conduct, and at the same time control the inductive switch Q3 to conduct, pulling the input end of the inverter U0 low to the ground, so that the inverter U0 outputs a high-level signal to the control switch K1; when there is no abnormally staying tray at the discharge port, the emitted light will not be reflected, and when the receiving triode Q2 cannot receive the reflected optical signal, it will turn off, and at the same time control the inductive switch Q3 to turn off, pulling the input end of the inverter U0 high to the power supply voltage, so that the inverter U0 outputs a low-level signal to the control switch K1; at the same time, in order to supply power to the light-emitting diode Q1 to make it emit optical signals normally, a first resistor R1 is arranged in the tray detection module 1 and connected to the DC power supply VCC, which plays a role in current limiting and voltage division to ensure the normal power supply of the DC power supply VCC to the light-emitting diode Q1 and protect the circuit. The specific types and implementation methods of the first resistor R1, the light-emitting diode Q1, the receiving triode Q2, the inductive switch Q3 and the inverter U0 are not particularly limited in this application. The inductive switch Q3 can be implemented by a switching device such as a triode.

[0091] As a specific embodiment, such as Figure 4 and Figure 5As shown, taking the push hook as an example of operating based on the control of the motor frequency converter and the conveyor motor, the power supply module first transforms the input 220V AC power through the transformer T to obtain an AC voltage of about 30V. After bridge rectification and capacitor filtering, it is regulated by the voltage regulator LDO to obtain a standard 24V DC power supply VCC. The positive and negative poles of the 24V DC power supply VCC are respectively connected to the positive and negative poles of the optical reflection sensor. When the light emitted by the emitting diode Q1 of the optical reflection sensor is blocked by the tray staying at the outlet and the corresponding reflected light returns to the receiving triode Q2, the signal of the receiving triode Q2 is internally processed by the induction switch Q3 and the inverter U0 and then outputs a high-level signal to the buzzer and the relay coil. The buzzer emits an alarm sound, and the relay coil is energized. Under the action of the magnetic field, the normally closed point is switched to the off state. After the feeding signal of the motor frequency converter is disconnected, the conveyor motor of the push hook stops operating. When the tray at the discharge port is removed and the receiving triode Q2 of the optical reflection sensor does not detect the reflected light, the signal of the receiving triode Q2 is internally processed by the induction switch Q3 and the inverter U0 and then outputs a low level. The buzzer and the relay coil lose power, the alarm sound of the buzzer disappears, the relay coil loses voltage, the magnetic field disappears, and the position of the normally closed contact that was just disconnected is restored to the on state under the action of the internal spring of the relay. The feeding signal of the motor frequency converter is restored, and the conveyor motor of the push hook continues to operate.

[0092] Specifically, the tray detection module 1 specifically includes a first resistor R1, an emitting diode Q1, a receiving triode Q2, an induction switch Q3, and an inverter U0. The emitting diode Q1 and the receiving triode Q2 are used to detect whether the tray stays abnormally through the process of light reflection, and the induction switch Q3 and the inverter U0 are used to further process the signal output by the receiving triode Q2 to ensure that the finally output level signal can accurately control the push hook; the entire circuit structure is simple and easy to implement, which is beneficial to the simple implementation of the entire anti-rear-end collision circuit.

[0093] As an optional embodiment, the tray detection module 1 further includes:

[0094] A second resistor R2, the first end of which is respectively connected to the first end of the receiving triode Q2 and the first end of the first resistor R1, and the second end of which is respectively connected to the input end of the inverter U0 and the first end of the induction switch Q3;

[0095] A third resistor R3, the first end of which is grounded;

[0096] A fourth resistor R4, the first end of which is respectively connected to the second end of the third resistor R3 and the second end of the receiving triode Q2, and the second end of which is connected to the control end of the induction switch Q3.

[0097] It is not difficult to understand that the tray detection module 1 can also be provided with a second resistor R2, a third resistor R3, and a fourth resistor R4. The second resistor R2 directly connects the input terminal of the inverter U0 to the positive electrode of the DC power supply VCC, ensuring that the input terminal of the inverter U0 can be pulled to a high-level state when the receiving triode Q2 is turned off. At the same time, a third resistor R3 and a fourth resistor R4 are additionally provided at the control terminal of the induction switch Q3 to provide a stable operating bias point for the induction switch Q3, ensuring the accurate control of the receiving triode Q2 over the induction switch Q3 and avoiding misoperation of the induction switch Q3. The specific types and implementation methods of the second resistor R2, the third resistor R3, and the fourth resistor R4 are not particularly limited in this application.

[0098] Specifically, a second resistor R2, a third resistor R3, and a fourth resistor R4 can be further added to the tray detection module 1 to further improve the accuracy and reliability of the operating process of the induction switch Q3 and the inverter U0, ensuring the accurate operation of the control switch K1; the entire circuit structure is simple and easy to implement, which is conducive to the simple implementation of the entire anti-rear-end collision circuit.

[0099] As an alternative embodiment, the tray detection module 1 further includes:

[0100] A fourth capacitor C4, with the first end grounded and the second end connected to the output terminal of the inverter U0.

[0101] It is not difficult to understand that a parallel-connected fourth capacitor C4 can be further added between the output terminal of the inverter U0 and the ground. By filtering through the fourth capacitor C4, the accuracy and reliability of the level signal output to the control switch K1 are improved, and the level signal finally output by the tray detection module 1 is further stabilized with the help of the fourth capacitor C4. The specific type and implementation method of the fourth capacitor C4 are not particularly limited in this application.

[0102] Specifically, a fourth capacitor C4 can be further added to the tray detection module 1 to further improve the accuracy and reliability of the output signal of the entire tray detection module 1, ensuring the accurate operation of the control switch K1; the entire circuit structure is simple and easy to implement, which is conducive to the simple implementation of the entire anti-rear-end collision circuit.

[0103] To solve the above technical problems, the present utility model further provides a tray control device, including a controller and the anti-rear-end collision circuit of the tray as described above.

[0104] It is not difficult to understand that the controller can control the operation of the control switch according to different level signals output by the tray detection module, thereby realizing the control process of anti-rear-end collision of the tray. At the same time, the controller can also perform other controls on the tray according to application requirements, which are not particularly limited in this application.

[0105] For the introduction of a tray control device provided by the present utility model, please refer to the embodiments of the anti-rear-end collision circuit of the tray above. The present utility model will not be elaborated herein.

[0106] To solve the above technical problems, the present utility model further provides a tray system for a reflow oven, which includes the aforementioned tray control device and a plurality of trays.

[0107] For the introduction of a tray system for a reflow oven provided by the present utility model, please refer to the embodiments of the anti-rear-end collision circuit of the tray above. The present utility model will not be elaborated herein.

[0108] It should also be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0109] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rear-end collision prevention circuit for a pallet, characterized in that: include: A tray detection module is provided at the discharge port of the reflow furnace, and is used to detect whether a tray is staying at the discharge port of the reflow furnace, and output a corresponding level signal according to the detection result; A control switch connected in series in the control loop of the push hook of the reflow furnace, with a control end connected to the output end of the tray detection module, is used to turn on or off based on the level signal output by the tray detection module.

2. The anti-rear-end collision circuit of a pallet as claimed in claim 1, characterized in that: The control switch is a relay; The relay includes a coil and a normally closed contact, the coil is connected to the output end of the tray detection module, the normally closed contact is connected in series in the control circuit of the push hook of the reflow furnace, when the discharge port of the reflow furnace is blocked by a tray, the coil is energized; when the discharge port of the reflow furnace is not blocked by a tray, the coil is de-energized.

3. The anti-rear-end collision circuit of a pallet as claimed in claim 1, characterized in that: Also includes: A power supply module, whose input end is connected to the AC mains and whose output end is connected to the power supply end of the tray detection module, is used to convert the AC mains into a DC power supply required by the tray detection module.

4. The anti-rear-end collision circuit of a pallet as claimed in claim 3, characterized in that: The power module comprises: A transformer, wherein a first end of a primary winding is connected to a live wire of the AC mains, and a second end is connected to a neutral wire of the AC mains; A rectifier bridge, a first input end connected to a first end of a secondary winding of the transformer, and a second input end connected to a second end of the secondary winding of the transformer; A first capacitor has a first end connected to the first output end of the rectifier bridge and serving as the first output end of the power module, and a second end connected to the second output end of the rectifier bridge and serving as the second output end of the power module.

5. The anti-rear-end collision circuit of a pallet as claimed in claim 4, characterized in that: The power module also includes: A second capacitor; A voltage stabilizer, whose input end is respectively connected to the first end of the first capacitor, the first end of the second capacitor and the first output end of the rectifier bridge; A third capacitor has a first end connected to the output end of the regulator and serves as the first output end of the power module, and a second end respectively connected to the second end of the second capacitor, the second end of the first capacitor and the second output end of the rectifier bridge and serves as the second output end of the power module.

6. The anti-rear-end collision circuit of a pallet as claimed in claim 5, characterized in that: The power module also includes: A diode, an anode of which is respectively connected to the output end of the regulator and the first end of the third capacitor, and a cathode of which is respectively connected to the second end of the third capacitor, the second end of the second capacitor, the second end of the first capacitor and the second output end of the rectifier bridge.

7. The anti-rear-end collision circuit of a pallet according to any one of claims 1 to 6, characterized in that: The pallet detection module comprises: A first resistor, a first end of which is connected to a DC power supply; An emitting diode is arranged at the discharge port of the reflow furnace, the first end of which is connected to the second end of the first resistor and the second end of which is grounded, and is used to emit an optical signal; A receiving transistor disposed at the discharge port of the reflow furnace, configured to be turned on when a reflected signal of the optical signal is received, and turned off when no reflected signal of the optical signal is received; An inverter, whose output end serves as an output end of the tray detection module; The induction switch has a first end connected to the input end of the inverter, the first end of the first resistor and the first end of the receiving transistor respectively, a control end connected to the second end of the receiving transistor, and a second end grounded; and is used to be turned on when the receiving transistor is turned on, and turned off when the receiving transistor is turned off.

8. The anti-rear-end collision circuit of a pallet as claimed in claim 7, characterized in that: The pallet detection module also includes: A second resistor, a first end of which is respectively connected to the first end of the receiving transistor and the first end of the first resistor, and a second end of which is respectively connected to the input end of the inverter and the first end of the sensing switch; a third resistor, a first end of which is grounded; A fourth resistor has a first end connected to the second end of the third resistor and the second end of the receiving transistor respectively, and a second end connected to the control end of the sensing switch.

9. A pallet control device, characterized in that: The invention comprises a controller and an anti-rear-end collision circuit of a pallet as claimed in any one of claims 1 to 8.

10. A tray system for a reflow oven, characterized in that: It comprises the pallet control device as claimed in claim 9 and a plurality of pallets.

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