Nut welding fool-proof device

Abstract

The utility model discloses a nut welding foolproof device, including spot welder, and spot welder sets up the upstroke height inductor and spot welder counter, still include PLC programmable logic controller, and programmable logic controller electric nature PLC electric nature connects the upstroke height inductor, spot welder counter, nut detection mechanism, pneumatic cylinder and optical sensor, the piston rod on pneumatic cylinder connects the sliding door, and the finished product storage box is set below the sliding door, and the emission end of optical sensor and receiving end are opposite and set in the finished product storage box both sides of the drop port, the utility model does not depend on the attention, proficiency or responsibility of operator, and the whole mistake proof process is completed by sensor and PLC automatically, effectively avoids the missed inspection, wrong judgment caused by personnel fatigue, negligence and other reasons, guarantees the stability and consistency of product quality, fundamentally avoids the major loss such as stop line, rework, even product scrapping caused by the nut shortage to the customer.

Description

Technical Field

[0001] This utility model belongs to the technical field of welding, and in particular to a foolproof device for welding nuts. Background Technology

[0002] In automobile manufacturing, defective nuts can cause vehicle scrapping during the manufacturing process, resulting in significant cost losses. Existing technologies typically prevent defective nuts from originating at their source by precisely controlling current and voltage, optimizing electrode materials and shapes, optimizing welding parameters, real-time monitoring and adjustment, and incorporating sensors to detect defective nuts in post-process error-proofing designs. However, these measures do not address the root cause of the problem.

[0003] During mass production, human negligence and abnormal power supply to equipment are unavoidable. In particular, when sensors fail in the later process, there is still a risk that defective nuts will flow into the downstream production line, which will cause difficulties in repair, prolong the repair time, or even make it impossible to repair, resulting in the scrapping of the entire vehicle and waste of costs.

[0004] In summary, the technical problem this utility model aims to solve is to develop a nut shortage prevention device that can fundamentally eliminate nut shortages and avoid cost losses caused by rework, repairs, or product scrap. Utility Model Content

[0005] In response to the problems raised above, this utility model proposes a nut welding error prevention device, the specific solution of which is as follows:

[0006] A nut welding error prevention device includes a spot welding machine, wherein the spot welding machine is equipped with an upper stroke height sensor and a spot welding machine counter;

[0007] It also includes a PLC programmable logic controller, which is electrically connected to the upper stroke height sensor, the spot welding machine counter, the nut detection mechanism, the cylinder, and the optical sensor.

[0008] The piston rod on the cylinder is connected to the sliding door, and a finished product storage box is set below the sliding door. The transmitting end and receiving end of the optical sensor are arranged opposite each other on both sides of the delivery port of the finished product storage box.

[0009] Preferably, the upper travel height sensor includes a height gauge, an infrared sensor, and a fixed bracket;

[0010] The fixed bracket is fixedly installed on the upper electrode fixing seat of the spot welding machine. One end of the height gauge is hinged to the fixed bracket, and the other end is provided with a groove. The infrared sensor is fixedly installed on the upper end of the spot welding machine and is arranged opposite to the grooved end of the height gauge.

[0011] Preferably, the spot welding machine counter is built into the control system of the spot welding machine and is electrically connected to the upper stroke height sensor. When the upper stroke height sensor triggers a valid welding signal, the value of the spot welding machine counter is incremented once.

[0012] Preferably, the nut detection mechanism includes a positioning block and at least one nut sensor; the positioning block is provided with a positioning pin that matches the shape of the workpiece; the nut sensor is mounted on the positioning block, and the position of its probe corresponds to the nut hole on the workpiece.

[0013] Preferably, the nut sensor is an inductive proximity switch.

[0014] Preferably, the cylinder is a pneumatic cylinder, and its cylinder body is fixed on the shelf where the finished product storage box is located.

[0015] Preferably, the optical sensor is a through-beam photoelectric sensor, with its transmitter and receiver respectively installed on both sides of the shelf where the finished product storage box is located.

[0016] Preferably, the sliding door is a cover made of metal sheet, the shape of which is adapted to the loading port of the finished product storage box.

[0017] The beneficial effects of this utility model are:

[0018] Through the coordinated efforts of multiple mechanisms, the entire process from source to outflow is automated and error-proofed. The system is designed with triple error-proofing logic; any failure in any link will lock the system, preventing the workpiece from flowing into the qualified area. Through physical isolation via a cylinder-operated sliding door and strict electrical control logic, the system can 100% prevent defective nuts from being placed in the finished product storage box, thus ensuring that only qualified products are delivered to the next process.

[0019] Operators simply need to place the workpieces according to the procedure; the system's opening, detection, release, and closing are all completed automatically, reducing human intervention, standardizing the work process, and improving production efficiency and automation. This device does not rely on the operator's attention, skill, or sense of responsibility; the entire error-proofing process is automatically completed by sensors and a PLC, effectively avoiding missed inspections and misjudgments caused by human fatigue or negligence. This ensures the stability and consistency of product quality, fundamentally preventing significant losses to customers due to missing nuts, such as line stoppages, rework, or even product scrapping. Attached Figure Description

[0020] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of this utility model. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0021] Figure 1 This is a three-dimensional schematic diagram of the device of this utility model;

[0022] Figure 2 This is a schematic diagram illustrating the actual application of this utility model;

[0023] In the picture:

[0024] 1-Upper travel height sensor; 101-Height gauge; 102-Infrared sensor; 103-Fixed bracket; 2-Spot welding machine counter; 3-Nut detection mechanism; 301-Positioning block; 4-Cylinder; 5-Optical sensor; 6-Finished product storage box. Detailed Implementation

[0025] First, it should be noted that the specific structure, features, and advantages of this utility model will be described in detail below by way of examples. However, all descriptions are for illustrative purposes only and should not be construed as limiting the utility model in any way. Furthermore, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the accompanying drawings, can still be arbitrarily combined or deleted among these technical features to obtain more other embodiments of this utility model that may not be directly mentioned herein. Additionally, for the sake of simplifying the drawings, the same or similar technical features may be indicated only in one place in the same drawing.

[0026] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] The following is in conjunction with the appendix Figure 1 - Appendix Figure 2 This utility model is described in detail.

[0028] Example 1:

[0029] like Figure 1 As shown, a nut welding error prevention device includes a spot welding machine, wherein the spot welding machine is equipped with an upper stroke height sensor 1 and a spot welding machine counter 2;

[0030] It also includes a PLC programmable logic controller, which is electrically connected to the upper stroke height sensor 1, the spot welding machine counter 2, the nut detection mechanism 3, the cylinder 4 and the optical sensor 5;

[0031] The piston rod on the cylinder 4 is connected to the sliding door, and a finished product storage box (6) is set below the sliding door. The transmitting end and receiving end of the optical sensor 5 are arranged opposite each other on both sides of the delivery port of the finished product storage box 6.

[0032] Working principle:

[0033] In this embodiment, the upper stroke height sensor 1 is used to detect the downward stroke of the upper electrode of the spot welding machine to control the spot welding machine to discharge welding; the spot welding machine counter 2 is used to count the number of successful weldings; the nut detection mechanism 3 is used to detect whether the nut on the workpiece is missing; the sliding door is used to open or close the loading port of the finished product storage box 6; and the optical sensor 5 is used to detect whether the workpiece is placed into the finished product storage box 6.

[0034] This device uses an upper stroke height sensor 1 as a key. It utilizes the sensor principle to detect the downward stroke distance during spot welding, thereby controlling the spot welding machine's electrical discharge welding. If the upper stroke distance of the spot welding machine exceeds the set standard stroke distance without a nut installed, the equipment will not discharge weld, ensuring that the nut is indeed involved in the welding process and preventing defective products.

[0035] The spot welding machine counter 1, the infrared sensor 102 of the upper stroke height sensor 1, the nut sensor of the nut detection mechanism 3, the optical sensor 5, and the solenoid valve of the cylinder 4 are all electrically connected to the PLCC programmable logic controller.

[0036] The PLC receives the counting signal from the spot welding machine counter 2 and the detection signal from the nut detection mechanism 3. Only when it simultaneously receives a signal indicating that the count has reached the target and a signal indicating that the nut is present, it indicates that the workpiece has completed nut welding and that the nut detection mechanism 3 has detected that all nuts are present on the workpiece. Only then does it output an opening signal to the solenoid valve of the cylinder 4 to drive the sliding door above the finished product storage box 6 to open.

[0037] The PLC simultaneously receives the sensing signal from the optical sensor 5. When the operator puts the qualified workpiece into the finished product storage box 6, the optical sensor 5 is triggered. Only when it receives a signal indicating that the workpiece has been placed will it output a closing signal to the cylinder 4, controlling the cylinder to push and pull the door 5 to close, and enter the work cycle of the next product.

[0038] If the value of the spot welding machine counter 1 fails to meet the standard or the nut detection mechanism 3 detects a missing nut during the intermediate process, the PLC will lock the cylinder 4 to prevent it from opening, thus fundamentally preventing defective products from flowing into the subsequent process.

[0039] The entire process can effectively prevent defective nuts from being placed in the finished product storage box 6 in the event of human negligence or equipment malfunction, ensuring that the product quality meets customer requirements and eliminating cost losses caused by defective nuts.

[0040] Furthermore, in the embodiments, the upper travel height sensor 1 may include a height ruler 101, an infrared sensor 102, and a fixed bracket 103.

[0041] The fixed bracket 103 is fixedly installed on the upper electrode fixing seat of the spot welding machine. One end of the height gauge 101 is hinged to the fixed bracket 103, and the other end is provided with a groove. The infrared sensor 102 is fixedly installed on the upper end of the spot welding machine and is arranged opposite to the grooved end of the height gauge 101.

[0042] In this embodiment, the upper stroke height sensor 1 consists of an infrared sensor 102, a height gauge 101, and a fixed bracket 103. The fixed bracket 103 is mounted on the upper electrode mounting base of the spot welding machine, the height gauge 101 is locked onto the fixed bracket, and the infrared sensor 102 is fixedly installed on the upper body of the spot welding machine.

[0043] The height gauge 101 is elongated, with a groove 0.4mm wide and 6cm deep cut at one end. When the upper electrode of the spot welding machine is pressed down, if a nut is placed on the workpiece, the nut will slightly lift the upper electrode, reducing the swing amplitude of the height gauge 101, and the groove will enter the sensing area of ​​the infrared sensor 102. If no nut is placed, the upper electrode will be pressed down to a lower position, causing the height gauge 101 to swing significantly, and the groove will deviate from the sensing area. The infrared sensor 102 will then fail to detect the signal, thus cutting off the discharge circuit of the spot welding machine and preventing welding from occurring. The core function of the groove design is to prevent nuts with protrusion heights that do not conform to the drawing specifications from being mistakenly used in the welding process.

[0044] Furthermore, in the embodiments, the spot welding machine counter 2 can be built into the control system of the spot welding machine and electrically connected to the upper stroke height sensor 1. When the upper stroke height sensor 1 triggers a valid welding signal, the value of the spot welding machine counter 2 is incremented once.

[0045] In this embodiment, the spot welding machine counter 1 is electrically connected to the upper stroke height sensor 1, and the counter value is incremented only once when the upper stroke height sensor 1 triggers a valid welding signal.

[0046] Furthermore, in the embodiments, the nut detection mechanism 3 may include a positioning block 301 and at least one nut sensor; the positioning block 301 is provided with a positioning pin that matches the shape of the workpiece; the nut sensor is mounted on the positioning block 301, and its probe position corresponds to the nut hole position on the workpiece.

[0047] In this embodiment, the nut detection mechanism 3 is located on the side of the finished product storage box 6. It includes a positioning block 301 for supporting and positioning the workpiece, and at least one nut sensor. The positioning block 301 is provided with a positioning pin that matches the shape of the workpiece, ensuring that after the workpiece is placed, the nut hole on it can be accurately aligned with the probe of the nut sensor.

[0048] The nut sensor is connected to the PLC programmable logic controller via a signal cable. After the workpiece is welded, the nut sensor will detect whether there are any missing or incomplete nuts on the workpiece. If the workpiece is found to be welded successfully, an electronic signal will be transmitted to the cylinder to open the sliding door.

[0049] Furthermore, in the embodiments, the nut sensor can also be considered as an inductive proximity switch.

[0050] Furthermore, in the embodiments, the cylinder 4 can be considered as a pneumatic cylinder, and its cylinder body is fixed on the shelf where the finished product storage box 6 is located.

[0051] In this embodiment, the sliding door 4 of the cylinder 4 is a mechanical structure, consisting of a mechanical cylinder 4 and a door body. One end of the cylinder 4 is connected to the door body, and the whole assembly is installed on the finished product shelf. The sliding door is a cover plate made of metal sheet. Under normal conditions, the cover plate presses against the finished product storage box 6 on the shelf to form a seal. The sliding door is driven by the cylinder 4 to achieve reciprocating motion, thereby opening or closing the loading port of the finished product storage box 6.

[0052] Furthermore, in the embodiments, the optical sensor 5 can be considered as a through-beam photoelectric sensor, with its transmitting end and receiving end respectively installed on both sides of the shelf where the finished product storage box 6 is located.

[0053] In this embodiment, the optical sensor 5 is an electronic component consisting of a pair of transmitters (light emitters) and receivers (light receivers), installed on both sides of the finished product shelf, directly above the finished product storage box 6 and below the sliding door cover. After the sliding door is opened, if the optical sensor 5 senses that a component has been placed into the finished product storage box 6, it will immediately send an electronic signal to control the sliding door to close.

[0054] Furthermore, in the embodiments, the sliding door can be a cover made of metal sheet, the shape of which is adapted to the loading port of the finished product storage box 6.

[0055] To further illustrate the effects of the embodiments of this utility model, such as Figure 2 The diagram shown is a schematic of the device in practical application.

[0056] The operating procedure for this device is as follows:

[0057] S1. Place the workpiece:

[0058] The operator places the workpiece to be welded on the lower electrode of the spot welding machine and puts the nut in the designated position.

[0059] S2. Induction and Welding:

[0060] The upper electrode of the spot welding machine is pressed down.

[0061] If there is a nut: The nut will slightly lift the upper electrode, so that the groove of the height gauge 101 of the upper stroke height sensor 1 enters the infrared sensing area, triggering the infrared sensor 102, and the spot welding machine will discharge and weld normally.

[0062] Without a nut: the upper electrode is pressed down deeper, the height gauge 101 swings more, the groove deviates from the sensing area, the external sensor 102 has no signal, the spot welding machine cuts off the discharge circuit, and welding is stopped.

[0063] Each time the upper travel height sensor 1 triggers a valid welding signal, the built-in spot welding machine counter 2 increments by one. When the value of the spot welding machine counter 2 reaches a preset value, for example, if the workpiece requires welding 4 nuts and the value reaches 4, it indicates that all nuts have been welded, and the PLC receives a signal.

[0064] S4. Nut re-inspection:

[0065] The operator removes the welded workpiece and places it on the positioning block 301 of the nut detection mechanism 3. The workpiece is precisely fixed by the positioning pin, and the nut hole on it is aligned with the nut sensor. The nut sensor detects whether there is a nut in each hole.

[0066] When the value of the spot welding machine counter 2 reaches the standard and the nut detection mechanism 3 detects that all nuts are present, the PLC sends a signal to the solenoid valve of the cylinder 4, the cylinder 4 actuates, and drives the sliding door to open. The operator puts the inspected and qualified workpieces into the finished product storage box (6) through the opened delivery port.

[0067] If the value of the spot welding machine counter 2 is not up to standard or the nut detection mechanism 3 detects a missing nut, the PLC will lock the cylinder 4 and keep the sliding door closed, fundamentally preventing defective products from being put in.

[0068] S5. Automatic shutdown:

[0069] When the workpiece falls through the loading port of the finished product storage box 6, it blocks the light beam of the optical sensor 5. The optical sensor 5 immediately sends a signal to the PLC, which then controls the cylinder 4 to close the sliding door. After the sliding door closes, the system resets and prepares to enter the next work cycle.

[0070] The entire process requires triple verification. The first verification is performed by the upper stroke height sensor 1 to ensure that nuts are present before welding. The second verification is performed by the spot welding machine counter 2 to ensure that all nuts have been welded. The third verification is performed by the nut detection mechanism 3 to confirm that no nuts are missing. After triple verification, the cylinder push-pull door acts as the final actuator. It will only open if all verifications pass, thereby achieving mandatory physical isolation of defective products, preventing errors throughout the process, and achieving the goal of zero-defect outflow.

[0071] The above embodiments have provided a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made in accordance with the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A nut welding error prevention device, comprising a spot welding machine, characterized in that: The spot welding machine is equipped with an upper stroke height sensor (1) and a spot welding machine counter (2); It also includes a PLC programmable logic controller, which is electrically connected to the upper stroke height sensor (1), the spot welding machine counter (2), the nut detection mechanism (3), the cylinder (4), and the optical sensor (5). The piston rod on the cylinder (4) is connected to the sliding door, and a finished product storage box (6) is set below the sliding door. The transmitting end and receiving end of the optical sensor (5) are arranged opposite each other on both sides of the delivery port of the finished product storage box (6).

2. The nut welding error prevention device according to claim 1, characterized in that: The upper travel height sensor (1) includes a height gauge (101), an infrared sensor (102), and a fixed bracket (103). The fixed bracket (103) is fixedly installed on the upper electrode fixing seat of the spot welding machine. One end of the height gauge (101) is hinged to the fixed bracket (103), and the other end is provided with a groove. The infrared sensor (102) is fixedly installed on the upper end of the spot welding machine and is set opposite to the grooved end of the height gauge (101).

3. The nut welding error prevention device according to claim 1, characterized in that: The spot welding machine counter (2) is built into the control system of the spot welding machine and is electrically connected to the upper stroke height sensor (1). When the upper stroke height sensor (1) triggers a valid welding signal, the value of the spot welding machine counter (2) is incremented once.

4. The nut welding error prevention device according to claim 1, characterized in that: The nut detection mechanism (3) includes a positioning block (301) and at least one nut sensor; the positioning block (301) is provided with a positioning pin that matches the shape of the workpiece; the nut sensor is installed on the positioning block (301), and its probe position corresponds to the nut hole position on the workpiece.

5. The nut welding error prevention device according to claim 4, characterized in that: The nut sensor is an inductive proximity switch.

6. The nut welding error prevention device according to claim 1, characterized in that: The cylinder (4) is a pneumatic cylinder, and its cylinder body is fixed on the shelf where the finished product storage box (6) is located.

7. The nut welding error prevention device according to claim 1, characterized in that: The optical sensor (5) is a through-beam photoelectric sensor, with its transmitter and receiver installed on both sides of the shelf where the finished product storage box (6) is located.

8. The nut welding error prevention device according to claim 1, characterized in that: The sliding door is a cover made of metal sheet, the shape of which is adapted to the loading port of the finished product storage box (6).

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