Forklift gantry welding system

Abstract

The invention relates to the technical field of forklift welding, in particular to a forklift portal frame welding system which comprises a positioner provided with a turnover frame, a stand column positioning device is installed on the turnover frame, and a beam positioning device is used for positioning a first beam comprising a horizontal part and two vertical parts. The welding seam detection device is used for detecting the width of the inner welding seam and the outer welding seam in the vertical direction; the control device is connected with the welding seam detection device, the abutting device and the two welding devices and used for calculating the width difference between the outer welding seam and the inner welding seam according to the width of the inner welding seam and the width of the outer welding seam and controlling the abutting device to abut against the bottom end of the vertical part inwards or abut against the bottom end of the vertical part outwards based on the width difference. The vertical part has a non-vertical state that the vertical part inclines outwards or inwards relative to the stand column; and then the two welding devices are controlled to weld the outer welding seam and the inner welding seam at the same time, so that uneven shrinkage deformation caused by thermal stress in the welding process is actively counteracted, and the problem that deformation is difficult to accurately counteract due to the fact that a traditional technology only depends on post-correction is solved.

Description

Technical Field

[0001] This application relates to the field of forklift welding technology, and in particular to a forklift mast welding system. Background Technology

[0002] Forklifts, as important industrial handling equipment, are widely used for short-distance loading, unloading, and stacking of goods. The forklift mast, as the core load-bearing component, often employs a telescopic structure consisting of a carriage, a primary mast, and a secondary mast to meet the needs of operations at different heights. This multi-layered nested frame structure places extremely high demands on the welding precision and connection strength of each component.

[0003] In the traditional forklift mast welding process, components such as columns and beams are first pre-treated and spot-welded using clamping devices or welding fixtures to form the initial frame structure of the mast. After pre-fixation, secondary welding is then performed to comprehensively reinforce all connecting parts. This process relies on tooling fixtures to position and assemble the steel components, achieving component connection through step-by-step welding. The operation is cumbersome and highly dependent on the accuracy of manual positioning.

[0004] However, the aforementioned welding methods have significant drawbacks: Firstly, the step-by-step operation of pretreatment spot welding and secondary welding results in a lengthy process, increasing labor, time, and space costs. Multiple positioning operations may also introduce cumulative errors, affecting the overall structural accuracy of the mast. Secondly, the thermal stress generated during welding causes uneven contraction after localized expansion of components, leading to structural deformation. Traditional processes rely solely on post-weld corrections, which are insufficient to accurately offset this deformation, easily causing dimensional deviations and shape distortions in the mast, thus affecting the forklift's load-bearing capacity and operational safety. Therefore, effectively addressing the problem of welding thermal deformation while avoiding pretreatment spot welding and secondary welding has become a crucial area for improvement in existing technologies. Summary of the Invention

[0005] In order to effectively solve the problem of welding thermal deformation while avoiding pre-treatment spot welding and secondary welding, this application provides a forklift mast welding system.

[0006] The forklift mast welding system provided in this application adopts the following technical solution: A forklift mast welding system, comprising: Positioner equipped with a tilting frame; A column positioning device is installed on the flipping frame and is used to position two parallel columns. A beam positioning device is used to position a first beam, which includes a horizontal section and two vertical sections, such that the bottom surface of the vertical section abuts against the top surface of the column. A weld inspection device defines the distance between the inner and outer sides of the vertical part in the horizontal direction and the vertical distance between the column before welding as the inner weld and the outer weld. The weld inspection device is used to measure the width of the inner weld and the outer weld in the vertical direction. A top-supporting device is installed on the tilting frame and is used to face the inner and outer sides of the vertical part; Two welding devices, each comprising a robotic arm and a welding torch mounted on the robotic arm, are located to the side of the positioner; The control device, connected to the weld detection device, the abutting device, and the two welding devices, is used to calculate the width difference between the outer weld and the inner weld based on the width of the inner weld and the outer weld. Based on the width difference, it controls the abutting device to abut the bottom end of the vertical part inward relative to the outer side of the vertical part, or to abut the bottom end of the vertical part outward relative to the inner side of the vertical part, so that the vertical part has a non-vertical state of tilting outward or inward relative to the column. Then, it controls the two welding devices to weld the outer weld and the inner weld simultaneously.

[0007] By adopting the above technical solution, the forklift mast welding system achieves precise one-time positioning of the columns and beams through the column positioning device and the beam positioning device. With the help of the control device, the two welding devices simultaneously weld the external and internal welds, eliminating the step-by-step operation of pre-treatment spot welding and secondary welding in the traditional process. This effectively simplifies the process flow, reduces labor, time and space costs, and avoids the cumulative error caused by multiple positioning, thus improving the overall structural accuracy of the mast. In addition, the control device can control the vertical part to be pre-tilted to a non-vertical state based on the difference in width between the internal and external welds obtained by the weld detection device. This actively counteracts the uneven shrinkage deformation caused by thermal stress during welding, solving the problem that the traditional process relies solely on post-processing correction, which is difficult to accurately counteract deformation. This reduces mast size deviation and shape distortion, ensuring the load-bearing capacity and operational safety of the forklift.

[0008] Optionally, the weld inspection device includes a drive mechanism and an image processor and two industrial cameras mounted on the drive mechanism. The drive mechanism drives the two industrial cameras to be located on the inner and outer sides of the vertical part to capture images of the inner and outer welds. The image processor is connected to the industrial camera and is used to acquire images of the inner and outer welds captured by the industrial camera, and to obtain the widths of the outer and inner welds.

[0009] By adopting the above technical solution, the weld inspection device drives two industrial cameras to move synchronously to the inner and outer sides of the vertical part through the drive mechanism. It can simultaneously acquire images of the inner and outer welds. With the help of the image processor to analyze and process the images, it can accurately obtain the width data of the inner and outer welds in the vertical direction. This provides accurate and reliable raw parameters for the control device to calculate the width difference and determine the tilt angle of the vertical part. This ensures the accuracy of the subsequent anti-push device in controlling the tilt state of the vertical part. In turn, it provides data support for the welding device to effectively offset thermal deformation during synchronous welding, further improving the automation accuracy and reliability of forklift mast welding and ensuring the stability of the mast structure.

[0010] Optionally, the control device includes: An acquisition unit is used to acquire the widths of the outer weld and the inner weld; A comparison unit is used to compare the widths of the outer weld and the inner weld. A calculation unit is used to calculate the absolute value of the width difference between the outer weld and the inner weld; The abutting unit is used to control the abutting device to abut the bottom end of the vertical part outward based on the absolute value of the width difference between the outer weld and the inner weld when the width of the outer weld is greater than the width of the inner weld, so that the vertical part has a non-perpendicular state with an inward tilting target angle relative to the column; and to control the abutting device to abut the bottom end of the vertical part inward based on the absolute value of the width difference between the outer weld and the inner weld when the width of the outer weld is less than the width of the inner weld, so that the vertical part has a non-perpendicular state with an outward tilting target angle relative to the column. The welding unit is used to control the two welding devices to simultaneously weld the external weld and the internal weld after the supporting device is controlled to abut the bottom end of the vertical part.

[0011] By adopting the above technical solution, the acquisition unit of the control device accurately acquires the width of the outer and inner welds, providing basic data for subsequent control; the comparison unit and calculation unit compare the widths and calculate the absolute value of the width difference to achieve quantitative analysis of the weld state, providing clear parameter basis for the jacking action; based on the above quantitative results, the jacking unit controls the jacking device to jack the bottom of the vertical part from the inside and outside, so that the vertical part forms a target tilt angle that matches the weld width difference, realizing active prediction and precise cancellation of welding thermal deformation; after the jacking is in place, the welding unit controls the two welding devices to operate synchronously, eliminating the step-by-step process of pre-treatment spot welding and secondary welding, reducing the cumulative error caused by multiple positioning. Through the coordinated cooperation of each unit, the process is simplified, the cost is reduced, and the problem of difficult accurate correction of thermal deformation in traditional processes is effectively solved, further ensuring the welding accuracy and structural stability of the gantry.

[0012] Optionally, both the abutment device and the beam positioning device are configured to have a travel along the extension direction of the column.

[0013] By adopting the above technical solution, the working position can be flexibly adjusted according to the installation position of different crossbeams, without the need for frequent replacement or adjustment of tooling fixtures. This not only improves the adaptability of the equipment to gantry frames of different lengths and crossbeam distributions, but also reduces downtime and manual operation costs caused by tooling replacement.

[0014] Optionally, the abutting device includes two ejection mechanisms located on the inner and outer sides of the vertical portion, the ejection mechanisms comprising: A lead screw linear module is installed on the tilting frame; The top rod is fixed to the lead screw linear module and is used to face the side of the vertical part.

[0015] By adopting the above technical solution, high-precision driving and positioning of the push rod in the horizontal direction can be achieved. The mechanical transmission characteristics of the linear screw module can ensure precise control of the push rod extension length, making the tilt angle adjustment of the vertical part more accurate, thereby reliably offsetting welding thermal deformation.

[0016] Optionally, the abutment unit, based on a preset mapping relationship between the absolute value of the width difference between the outer weld and the inner weld and the vertical tilt angle, and a preset mapping relationship between the vertical tilt angle and the extension length of the push rod, obtains the target tilt angle of the vertical part according to the absolute value of the width difference between the outer weld and the inner weld calculated by the calculation unit, thereby obtaining the actual extension length of the push rod, and controls the extension of the push rod based on the actual extension length of the push rod, so that the vertical part tilts to the target tilt angle.

[0017] By adopting the above technical solution, the jacking unit can directly convert the weld width difference data into precise action parameters of the jack by calling the preset dual mapping relationship between the absolute value of the width difference and the vertical tilt angle, and between the vertical tilt angle and the extension length of the jacking rod. This makes the control of the vertical tilt angle more quantitative and consistent, speeds up the response speed from weld detection to jacking action, and, together with the simplification of the overall process, further reduces time costs and cumulative error risks, ensuring the structural accuracy and stability of the gantry after welding.

[0018] Optionally, the push rod is equipped with a temperature sensor, and the control device is connected to the temperature sensor to monitor the weld temperature field monitored by the temperature sensor in real time. When the weld temperature field exceeds the preset temperature, the compensation extension length is calculated based on the extension length of the push rod and the compensation coefficient. The compensation extension length is used as the actual extension length of the push rod, and the extension of the push rod is controlled based on the actual extension length of the push rod.

[0019] By adopting the above technical solution, the control device can promptly capture the intensified thermal deformation caused by abnormal temperature rise during the welding process. When the temperature exceeds the preset value, the compensation extension length is calculated based on the current extension length of the push rod and the compensation coefficient at the corresponding temperature. Then, the actual extension amount of the push rod is dynamically adjusted, which makes up for the limitations of static compensation in the preset mapping relationship when the temperature fluctuates. This realizes real-time dynamic correction of welding thermal deformation, avoids tilt angle deviation or insufficient deformation compensation caused by abnormal temperature, and effectively solves the problem of additional deformation caused by temperature changes during the welding process that is difficult to cope with in traditional processes.

[0020] Optionally, the beam positioning device is also used to position the second beam so that both ends of the second beam are located on opposite sides of the two columns; the control device is also used to control the two welding devices to weld the two ends of the second beam simultaneously.

[0021] By adopting the above technical solution, the control device controls two welding devices to weld the two ends of the second crossbeam simultaneously, avoiding the lengthy process caused by traditional step welding, reducing the cumulative error caused by multiple positioning, and balancing the welding heat input by welding the two ends synchronously, so that the thermal deformation at both ends of the second crossbeam cancels each other out, reducing the risk of structural distortion caused by welding on one side, further improving the overall welding accuracy and structural stability of the gantry, and effectively solving the problems of difficulty in adapting to diverse crossbeam structures and insufficient thermal deformation correction in traditional processes.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. By using the column positioning device and the beam positioning device for precise positioning in one step, combined with the synchronous welding of the welding device, the step-by-step operation of pre-treatment spot welding and secondary welding in the traditional process is eliminated, which greatly simplifies the process flow, reduces labor, time and space costs, and avoids the cumulative error caused by multiple positioning. This effectively improves the overall structural accuracy of the gantry and fundamentally solves the problems of lengthy process and error accumulation in the traditional process.

[0023] 2. By using the weld width data obtained by the weld inspection device, the control device calls the preset dual mapping relationship through the abutment unit to drive the abutment device to precisely control the tilt angle of the vertical part. This achieves active prediction and precise offsetting of welding thermal deformation, overcoming the problem that traditional processes rely solely on post-processing corrections and cannot cope with structural deformation caused by thermal stress. It significantly reduces mast size deviation and shape distortion, ensuring the load-bearing capacity and operational safety of the forklift.

[0024] 3. The system, through the movement of the supporting device and the crossbeam positioning device along the extension direction of the column, as well as the compatible positioning and synchronous welding design of the second crossbeam, has a wide adaptability to gantry frames of different specifications and crossbeam distributions. It eliminates the need for frequent changes of tooling fixtures, reducing changeover costs and downtime. At the same time, by balancing heat input through synchronous welding, it further improves the consistency and stability of welding multiple types of gantry frames, effectively solving the limitation of poor adaptability of traditional fixed tooling. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the forklift mast welding system in an embodiment of this application; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 This is a partial structural schematic diagram of the abutment device in an embodiment of this application; Figure 4 This is a schematic diagram of the forklift mast welding system in an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures: 10. Column; 20. First crossbeam; 30. Second crossbeam; 40. Horizontal section; 50. Vertical section; 1. Positioner; 11. Tilting frame; 2. Column positioning device; 3. Crossbeam positioning device; 4. Weld inspection device; 41. Drive mechanism; 42. Industrial camera; 5. Supporting device; 51. Lead screw linear module; 52. Top rod; 6. Welding device. Detailed Implementation

[0027] The following will be combined with the appendix Figure 1-4 The technical solutions in the embodiments of this application are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] Reference Figure 1 and Figure 2This application discloses a forklift mast welding system for welding the outer or inner mast of a forklift. Each outer or inner mast includes two parallel columns 10 and multiple crossbeams connecting the two columns 10. The multiple crossbeams include multiple first crossbeams 20 and multiple second crossbeams 30. Each first crossbeam 20 and second crossbeam 30 includes a horizontal portion 40 and two vertical portions 50. When the first crossbeam 20 is installed on the column 10, the bottom surfaces of the two vertical portions 50 of the first crossbeam 20 abut against the top surface of the column 10. The length of the horizontal portion 40 of the second crossbeam 30 is greater than that of the horizontal portion 40 of the first crossbeam 20. When the second crossbeam 30 is installed on the column 10, the two vertical portions 50 of the second crossbeam 30 are located on opposite sides of the column 10.

[0029] Reference Figure 1 The forklift mast welding system includes a positioner 1 equipped with a tilting frame 11, a column positioning device 2, a beam positioning device 3, a weld inspection device 4, a support device 5, two welding devices 6, and a control device.

[0030] The positioner 1 equipped with a tilting frame 11 mainly consists of a base, a tilting frame 11, and a tilting drive system. The tilting frame 11 is a rigid frame structure, serving as the mounting base for the column positioning device 2 and the supporting device 5. The tilting frame 11 is connected to the base via a rotating shaft and can tilt around a horizontal axis to adjust the mast's posture. The tilting drive system integrates a motor, reducer, and transmission mechanisms such as gear racks and pinions, and worm gears, enabling precise control of the tilting angle and speed of the tilting frame 11. This positions the mast in the optimal position for the welding device 6, providing a stable and flexible support platform for high-precision welding of the forklift mast. The positioner 1 equipped with the tilting frame 11 is existing technology and will not be described in detail.

[0031] The column positioning device 2 is installed on the tilting frame 11. Through mechanical clamps or pneumatic mechanisms, it can precisely fix two parallel columns 10, ensuring that the columns 10 maintain a preset spacing and verticality during welding, providing a reference for the subsequent positioning of the crossbeam components. In one embodiment, the column positioning device 2 consists of two rows of first electric grippers. Each column 10 is supported and held by one row of first electric grippers. The first electric grippers can adapt to the clamping requirements of columns 10 of different specifications and move synchronously with the tilting frame 11 through a rigid connection, ensuring the stability of the gantry during repositioning.

[0032] The beam positioning device 3 is used to position the first beam 20 and the second beam 30. In one embodiment, the beam positioning device 3 includes a robotic arm and a second electric gripper mounted on the robotic arm. The beam positioning device 3 grabs and transfers the first beam 20 or the second beam 30, positioning the first beam 20 or the second beam 30 above the column 10 and adapting it to the column 10.

[0033] It should be noted that when the first crossbeam 20 is placed on the column 10, the bottom surfaces of both vertical portions 50 of the first crossbeam 20 abut against the top surface of the column 10. Due to the machining accuracy deviations between the column 10 and the first crossbeam 20 during the cutting and stamping process, the thermal expansion and contraction effect of the material will cause uneven edges, resulting in local thickness differences or perpendicularity deviations. This prevents the contact surfaces of the vertical portions 50 and the column 10 from being completely fitted together, resulting in gaps between the bottom surfaces of the two vertical portions 50 of the first crossbeam 20 and the top surface of the column 10. In this application, this gap is defined as a weld. Specifically, the side of the vertical portion 50 facing the other vertical portion 50 in the same first crossbeam 20 is defined as the inner side, and the weld between the inner side and the top surface of the column 10 is the inner weld; the side of the vertical portion 50 away from the other vertical portion 50 is defined as the outer side, and the weld between the outer side and the top surface of the column 10 is the outer weld. Due to factors such as machining accuracy deviations and material elastic deformation, the widths of the inner and outer welds in the vertical direction are inconsistent.

[0034] The weld inspection device 4 is used to measure the vertical width of the inner and outer welds. (Refer to...) Figure 2 The weld inspection device 4 includes a drive mechanism 41, an image processor mounted on the drive mechanism 41, and two industrial cameras 42. During inspection, the two industrial cameras 42 are located on both sides of the column 10. In one embodiment, the drive mechanism 41 can be two robotic arms, each equipped with an industrial camera 42. The movement of the robotic arms moves the two industrial cameras 42 to both sides of the same vertical section 50, simultaneously capturing images of the inner and outer welds. The image processor is connected to the industrial cameras 42 and is used to acquire the images of the inner and outer welds captured by the industrial cameras 42. By analyzing the images using edge detection algorithms, the vertical width of the inner and outer welds is accurately calculated, providing a quantitative basis for subsequent pre-tilt control.

[0035] The supporting device 5 is slidably mounted on the tilting frame 11. Two supporting devices 5 are provided, each corresponding to one of the two uprights 10, and each has a travel distance along the extension direction of the uprights 10. A drive motor for moving the supporting device 5 is mounted on the tilting frame 11. (Refer to...) Figure 3 The abutting device 5 includes ejection mechanisms located on the inner and outer sides of the vertical section 50. Each ejection mechanism includes a lead screw linear module 51 and a push rod 52 fixed to the lead screw linear module 51. The push rod 52 faces the inner and outer sides of the vertical section 50. The lead screw linear module 51 is mounted on the tilting frame 11 and can drive the push rod 52 to move horizontally, thereby achieving abutting action on the bottom side of the vertical section 50. The abutting device 5 is configured to have a longitudinal stroke, and the point of action of the push rod 52 can be adjusted according to the position of the first crossbeam 20. Furthermore, by controlling the extension length of the push rod 52, the tilt angle of the vertical section 50 can be precisely controlled to actively counteract welding heat deformation.

[0036] Both welding devices 6 include robotic arms and welding torches mounted on the robotic arms, positioned to the side of the positioner 1. When welding the first crossbeam 20, they are responsible for the simultaneous welding of the outer and inner weld seams of the same vertical section 50 and column 10. When welding the second crossbeam 30, they are responsible for the simultaneous welding of the two vertical sections 50 of the second crossbeam 30 and column 10. The robotic arms are six-axis industrial robotic arms, whose motion trajectory and welding parameters can be dynamically adjusted according to the forklift mast (outer or inner mast). Combined with the mast's tilting posture, this achieves fully automated welding, ensuring consistent weld quality.

[0037] Reference Figure 4 The control device is connected to the weld inspection device 4, the abutment device 5, and two welding devices 6, and includes an acquisition unit, a comparison unit, a calculation unit, an abutment unit, and a welding unit. First, the acquisition unit collects the width data of the outer weld and the inner weld from the weld inspection device 4. The comparison unit compares the two sizes, and the calculation unit calculates the difference between the two (ΔW = width of the outer weld - width of the outer weld), and then obtains the absolute value of the width difference (|ΔW|). Then, based on the size relationship between the widths of the outer weld and the inner weld and the value of |ΔW|, the abutment unit calls the preset dual mapping relationship of "absolute value of width difference - vertical part tilt angle" and "vertical part tilt angle - extension length of the push rod" to control the abutment device 5 to abut the bottom end of the vertical part 50 from the inside and outside, so that the vertical part 50 produces a precise tilt angle relative to the column 10.

[0038] When the width of the outer weld is greater than the width of the inner weld, the abutting device 5 is controlled to abut the bottom of the vertical part 50 outward according to the absolute value of the difference in width between the outer weld and the inner weld, so that the vertical part 50 has a non-perpendicular state with an inward tilting target angle relative to the column 10; when the width of the outer weld is smaller than the width of the inner weld, the abutting device 5 is controlled to abut the bottom of the vertical part 50 inward according to the absolute value of the difference in width between the outer weld and the inner weld, so that the vertical part 50 has a non-perpendicular state with an outward tilting target angle relative to the column 10.

[0039] The control device achieves precise control based on two preset mapping relationships: a mapping relationship between the absolute value of the width difference and the tilt angle of the vertical section (determining the angle), and a mapping relationship between the tilt angle of the vertical section and the extension length of the push rod (converting into mechanical parameters). Through these mapping relationships, the extension length of the push rod is derived from the absolute value of the width difference, thereby controlling the movement of the push rod 52 to tilt the vertical section 50 to the target tilt angle. Finally, after the vertical section 50 is adjusted into place, the welding unit synchronously triggers the two welding devices 6 to complete the welding operation of the inner and outer welds.

[0040] Understandably, the mapping relationship between the absolute value of the width difference between the outer and inner welds and the tilt angle of the vertical part can be obtained by integrating historical data from actual production: First, collect successful welding data accumulated by similar welding equipment in long-term production, extract the absolute value of the width difference between the outer and inner welds (|ΔW|) under the corresponding working conditions and the actual tilt angle (θ) of the vertical part 50 relative to the column 10 after welding, and form a basic parameter library; Second, empirically calibrate the θ value in typical |ΔW| intervals, and supplement and correct fuzzy parameters in historical data; Finally, verify the results on the actual welding platform through trial and error experiments. For a specific |ΔW| value, use the θ value as the initial tilt angle of the vertical part 50 before welding, and gradually adjust the tilt angle according to the weld quality inspection results (such as the flaw detection pass rate and the uniformity of the penetration depth). After multiple iterations, determine the optimal θ value corresponding to the |ΔW|, and form an empirical mapping table with engineering applicability.

[0041] Based on the lever arm length from the point of action of the push rod 52 to the vertical part 50, the theoretical values ​​of the push rod extension length corresponding to different tilt angles are calculated using trigonometric functions. Then, the push rod 52 with different extension lengths is applied by the push device 5, and the tilt angle is measured by the tilt sensor. The measured values ​​are compared with the theoretical values ​​to form an initial mapping table. Finally, the corresponding parameters of the push rod extension length and tilt angle are finely adjusted according to the actual welding situation. After accumulating and optimizing multiple batches of production data, a stable and reliable mapping relationship is formed.

[0042] In one embodiment, a temperature sensor is provided on the push rod 52, and the control device is connected to the temperature sensor to monitor the weld temperature field monitored by the temperature sensor in real time. When the weld temperature field exceeds the preset temperature, the compensation extension length is calculated based on the extension length of the push rod and the compensation coefficient. The compensation extension length is used as the actual extension length of the push rod 52, and the extension of the push rod 52 is controlled based on the actual extension length of the push rod 52.

[0043] During welding, temperature is the core variable affecting the thermal deformation of materials. Changes in the temperature field of the welding area directly determine the distribution and release of thermal stress: excessively high temperatures lead to increased thermal expansion of the material, resulting in intensified shrinkage deformation after cooling, while excessively low temperatures may cause overcompensation of the preset tilt angle. Both of these will disrupt the original deformation offsetting balance. Temperature detection is precisely to capture the dynamic impact of temperature fluctuations on thermal deformation in real time during the welding process. Because the coefficient of thermal expansion and the rate of contraction of materials differ at different temperatures, even if the initial weld width difference is the same, temperature changes will cause the actual deformation to deviate from the expected value of the preset mapping relationship. Temperature-based compensation calculations can correct the extension length of the top rod by introducing a temperature coefficient to address the deviation between the real-time temperature and the preset reference temperature. This allows the tilt angle of the vertical part (50°) to dynamically adapt to the thermal deformation characteristics at the current temperature, avoiding insufficient or excessive compensation due to temperature fluctuations. This ensures accurate deformation offsetting throughout the welding process, further improving the dimensional accuracy and structural stability of the gantry welding.

[0044] Specifically, the setting of the compensation coefficient needs to be based on the material thermal deformation law and a large amount of experimental data. For the gantry and the first crossbeam 20, comparative tests are carried out in different welding temperature ranges (covering the temperature fluctuation range that may occur in actual production). The deviation between the actual thermal deformation of the weld and the theoretical deformation at each temperature is recorded. Combined with the influence of the extension length of the top rod on the tilt angle, the correlation curve between the temperature deviation (the difference between the real-time temperature and the preset reference temperature) and the compensation amount is fitted, and the compensation coefficient is determined in this way.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A forklift mast welding system, characterized in that, include: Positioner (1) equipped with a tilting frame (11); The column positioning device (2) is installed on the flipping frame (11) and is used to position two parallel columns (10); A beam positioning device (3) is used to position a first beam (20) including a horizontal part (40) and two vertical parts (50), so that the bottom surface of the vertical part (50) abuts against the top surface of the column (10); The weld inspection device (4) defines the distance between the inner and outer sides of the vertical part (50) in the horizontal direction and the vertical distance between the column (10) in the vertical direction before welding as the inner weld and the outer weld. The weld inspection device (4) is used to measure the width of the inner weld and the outer weld in the vertical direction. A top-supporting device (5) is installed on the flipping frame (11) and is used to face the inner and outer sides of the vertical part (50); Two welding devices (6), each welding device (6) includes a robotic arm and a welding torch mounted on the robotic arm, located to the side of the positioner (1); The control device, connected to the weld detection device (4), the abutment device (5), and the two welding devices (6), is used to calculate the width difference between the outer weld and the inner weld based on the width of the inner weld and the outer weld, and control the abutment device (5) to abut the bottom end of the vertical part (50) inward relative to the outer side of the vertical part (50), or to abut the bottom end of the vertical part (50) outward relative to the inner side of the vertical part (50), so that the vertical part (50) has a non-vertical state of tilting outward or inward relative to the column (10); and then control the two welding devices (6) to weld the outer weld and the inner weld simultaneously.

2. The forklift mast welding system according to claim 1, characterized in that, The weld inspection device (4) includes a drive mechanism (41), an image processor mounted on the drive mechanism (41), and two industrial cameras (42). The drive mechanism (41) drives the two industrial cameras (42) to be located on the inner and outer sides of the vertical part (50) to capture images of the inner weld and the outer weld. The image processor is connected to the industrial camera (42) and is used to acquire images of the inner weld and the outer weld taken by the industrial camera (42) to obtain the width of the outer weld and the inner weld.

3. The forklift mast welding system according to claim 2, characterized in that, The control device includes: An acquisition unit is used to acquire the widths of the outer weld and the inner weld; A comparison unit is used to compare the widths of the outer weld and the inner weld. A calculation unit is used to calculate the absolute value of the width difference between the outer weld and the inner weld; The abutting unit is used to control the abutting device (5) to abut the bottom end of the vertical part (50) outward based on the absolute value of the difference between the width of the outer weld and the inner weld when the width of the outer weld is greater than the width of the inner weld, so that the vertical part (50) has a non-perpendicular state with an inward tilting target angle relative to the column (10); when the width of the outer weld is less than the width of the inner weld, the abutting device (5) is controlled to abut the bottom end of the vertical part (50) inward based on the absolute value of the difference between the width of the outer weld and the inner weld, so that the vertical part (50) has a non-perpendicular state with an outward tilting target angle relative to the column (10); The welding unit is used to control the two welding devices (6) to simultaneously weld the outer weld and the inner weld after the abutting device (5) abuts the bottom end of the vertical part (50).

4. The forklift mast welding system according to claim 3, characterized in that, Both the abutment device (5) and the beam positioning device (3) are configured to have a travel along the extension direction of the column (10).

5. The forklift mast welding system according to claim 3, characterized in that, The abutting device (5) includes two ejection mechanisms located on the inner and outer sides of the vertical part (50), the ejection mechanisms including: A lead screw linear module (51) is installed on the tilting frame (11); The top rod (52) is fixed to the lead screw linear module (51) and is used to face the side of the vertical part (50).

6. The forklift mast welding system according to claim 5, characterized in that, The abutment unit, based on the preset mapping relationship between the absolute value of the width difference between the outer weld and the inner weld and the tilt angle of the vertical part (50), and the preset mapping relationship between the tilt angle of the vertical part (50) and the extension length of the top rod (52), obtains the target tilt angle of the vertical part (50) according to the absolute value of the width difference between the outer weld and the inner weld calculated by the calculation unit, thereby obtaining the actual extension length of the top rod (52), and controls the extension of the top rod (52) based on the actual extension length of the top rod (52) so that the vertical part (50) tilts to the target tilt angle.

7. The forklift mast welding system according to claim 6, characterized in that, The top rod (52) is equipped with a temperature sensor. The control device is connected to the temperature sensor and is used to monitor the weld temperature field monitored by the temperature sensor in real time. When the weld temperature field exceeds the preset temperature, the compensation extension length is calculated based on the extension length of the top rod (52) and the compensation coefficient. The compensation extension length is used as the actual extension length of the top rod (52). The extension of the top rod (52) is controlled based on the actual extension length of the top rod (52).

8. The forklift mast welding system according to claim 1, characterized in that, The beam positioning device (3) is also used to position the second beam (30) so that the two ends of the second beam (30) are located on opposite sides of the two columns (10); the control device is also used to control the two welding devices (6) to weld the two ends of the second beam (30) simultaneously.

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