Forklift mast welding system

Abstract

This technology proactively counteracts non-uniform shrinkage deformation caused by thermal stress during the welding process, solving the problem that conventional processes rely solely on post-processing, making it difficult to accurately counteract deformation. [Solution] The present invention relates to the field of forklift welding technology, and more particularly to a forklift mast welding system, and includes a displacement machine on which an inverting frame is arranged, a column positioning device attached to the inverting frame, a crossmember positioning device used to position a first crossmember including a horizontal section and two vertical sections, a weld joint detection device used to detect the longitudinal width of an inner weld joint and an outer weld joint, and a control device connected to the weld joint detection device, abutting device and two welding devices, which calculates the width difference between the outer weld joint and the inner weld joint based on the width of the inner weld joint and the outer weld joint, controls the abutting device to abut the bottom end of the vertical section inward or outward based on the width difference, so that the vertical section has a non-vertical state inclined outward or inward with respect to the column, and is subsequently used to control the two welding devices to weld the outer weld joint and the inner weld joint simultaneously.

Description

Technical Field

[0004] , , , ,

[0003]

[0001] This application relates to the field of forklift welding technology, and particularly to a forklift mast welding system.

Background Art

[0002] As an important industrial transportation device, forklifts are widely applied to the short-distance loading, unloading, and stacking operations of goods. The forklift mast, as the core loading member of the forklift, always adopts a telescopic structure composed of a carriage, a first-stage mast, and a second-stage mast to meet the working requirements of different heights. Such a multi-layer nested frame structure places extremely high requirements on the welding accuracy and connection strength of each member.

[0003] In the conventional forklift mast welding process, first, spot welding for pretreatment is performed on components such as columns and cross members by manually positioning with a clamping device or fixing with a welding tooling to form a preliminary frame structure of the mast. After the temporary fixing is completed, it is necessary to further perform secondary welding to comprehensively reinforce each connection site. This process requires using jigs and tools to position and connect the steel members, realizing member connection through step-by-step welding. The operation flow is complicated, and the dependence on the accuracy of manual positioning is high.<00>

[0004] However, the above welding method has the following significant shortcomings. The stepwise operation of pre-treatment spot welding and secondary welding makes the process redundant, increasing labor, time, and space costs. Furthermore, multiple positioning steps can introduce cumulative errors, affecting the overall structural accuracy of the mast. On the other hand, thermal stress generated during the welding process causes the material to expand locally and then contract unevenly, leading to structural deformation. Conventional processes rely solely on post-correction, making it difficult to accurately compensate for deformation, which easily leads to dimensional deviations and shape distortions in the mast, and further affects the load-bearing performance and safety of the forklift. How to avoid pre-treatment spot welding and secondary welding, and how to effectively solve the problem of thermal deformation caused by welding, is a key issue that conventional technology urgently needs to improve. [Overview of the project] [Problems that the invention aims to solve]

[0005] This invention provides a forklift mast welding system that avoids pre-treatment spot welding and secondary welding, and effectively solves the problem of thermal deformation caused by welding. [Means for solving the problem]

[0006] The forklift mast welding system provided in this application employs the following technical solutions.

[0007] A forklift mast welding system, A displacement machine with an inverting frame, A column positioning device attached to the aforementioned inverting frame for positioning two parallel columns, A cross member positioning device for positioning a first cross member including a horizontal section and two vertical sections, and for bringing the bottom surface of the vertical sections into contact with the top surface of the upright column, A welding joint detection device for detecting the width in the longitudinal direction of an inner welding joint and an outer welding joint, wherein the inner welding joint is defined as the distance in the longitudinal direction between the inner surface of the vertical portion in the lateral direction and the vertical column before welding, and the outer welding joint is defined as the distance in the longitudinal direction between the outer surface of the vertical portion in the lateral direction and the vertical column before welding, A butt device attached to the inverting frame and facing the inner and outer surfaces of the vertical portion, Each includes a robotic arm and a welding torch attached to the robotic arm, and two welding devices are located to the side of the displacement machine, The welding joint detection device, the butt device, and the control device connected to the two welding devices, which calculates the width difference between the outer welding joint and the inner welding joint based on the widths of the inner welding joint and the outer welding joint, and controls the butt device to abut the bottom end of the vertical part inward against the outer surface of the vertical part, or to abut the bottom end of the vertical part outward against the inner surface of the vertical part, so that the vertical part has a non-vertical state inclined outward or inward with respect to the vertical column, and subsequently controls the two welding devices to perform welding on the outer welding joint and the inner welding joint simultaneously.

[0008] In the above technical solution, the forklift mast welding system of the present invention achieves accurate primary positioning of the vertical column and cross member using a vertical column positioning device and a cross member positioning device. Combined with a control device, the two welding devices are driven to weld the outer and inner weld joints simultaneously, eliminating the stepwise operation of pre-treatment spot welding and secondary welding in conventional processes, effectively simplifying the process flow, reducing labor costs, time and space costs, and avoiding cumulative errors due to multiple positioning attempts, thereby improving the structural accuracy of the entire mast. Furthermore, the control device, based on the width difference between the inner and outer weld joints acquired by the weld joint detection device, controls the butt device to tilt the vertical section to a non-vertical state in advance, thereby actively canceling out uneven shrinkage deformation due to thermal stress during the welding process. This solves the problem in conventional processes where deformation is difficult to accurately cancel out because they rely only on post-correction, reducing dimensional deviations and shape distortions of the mast, and ensuring the load-bearing performance and work safety of the forklift.

[0009] Optionally, the weld joint detection device includes a drive mechanism, a graphics processor mounted on the drive mechanism, and two industrial cameras, the drive mechanism being driven to move both the inner and outer sides of the vertical portion of the two industrial cameras to capture images of the inner and outer weld joints. The graphics processor is connected to the industrial camera and is used to acquire images of the inner and outer weld seams captured by the industrial camera, and to obtain the widths of the outer and inner weld seams.

[0010] By employing the above technical solution, the weld joint detection device drives two industrial cameras to move synchronously on both the inner and outer sides of the vertical section using a drive mechanism, thereby enabling simultaneous collection of images of the inner and outer weld joints. Combined with image analysis processing by a graphics processor, this allows for accurate acquisition of longitudinal width data of the inner and outer weld joints. The control device calculates the width difference and provides accurate and reliable original parameters for determining the inclination angle of the vertical section, ensuring the accuracy of control over the inclination state of the vertical section by the subsequent butt device. Furthermore, it provides data support to effectively counteract thermal deformation during synchronous welding of the welding device, thereby improving the automation accuracy and reliability of forklift mast welding and ensuring the stability of the mast structure.

[0011] The control device may optionally be: An acquisition unit for obtaining the width of the outer welded joint and the inner welded joint, A comparison unit for comparing the widths of the outer welded joint and the inner welded joint, A calculation unit for calculating the absolute value of the width difference between the outer welded joint and the inner welded joint, A butt unit for controlling the butt device so that the bottom end of the vertical part abuts outward when the width of the outer welded joint is greater than the width of the inner welded joint, based on the absolute value of the width difference, so that the vertical part has a non-vertical state inclined inward at a target angle relative to the vertical column, and for controlling the butt device so that the bottom end of the vertical part abuts inward when the width of the outer welded joint is less than the width of the inner welded joint, based on the absolute value of the width difference, so that the vertical part has a non-vertical state inclined outward at a target angle relative to the vertical column, The system includes a welding unit for controlling two welding devices to weld the outer and inner weld seams simultaneously after the butt device has butted the bottom end of the vertical section.

[0012] By employing the above technical solution, the control unit's acquisition unit accurately acquires the widths of the outer and inner weld joints, providing basic data for subsequent control. The comparison unit and calculation unit compare the widths and calculate the absolute value of the width difference, thereby realizing a numerical analysis of the weld joint state and providing a clear parameter basis for the butt operation. Based on the above numerical results, the butt unit directs the butt device to perform inner and outer butts against the bottom edge of the vertical section, forming a target inclination angle in the vertical section that matches the width difference of the weld joint, thereby achieving proactive pre-prediction and accurate compensation for thermal deformation due to welding. After butting at a predetermined position, the welding unit controls the synchronized operation of the two welding devices, eliminating the stepwise flow of pre-treatment spot welding and secondary welding, and reducing cumulative errors due to multiple positioning attempts. Overall, the cooperation of each unit simplifies the process and reduces costs, while also effectively solving the problem of difficulty in accurately correcting thermal deformation in conventional processes, further ensuring the welding accuracy and structural stability of the mast.

[0013] The abutment device and the cross member positioning device are optionally arranged to have a movable stroke along the extending direction of the vertical column.

[0014] By adopting the above technical solution, the working position can be flexibly adjusted according to the mounting position of different cross members, eliminating the need to frequently change or adjust jigs and fixtures. This not only improves the suitability of the equipment for masts of different lengths and with different cross member distributions, but also reduces machine downtime and labor costs due to the change of jigs and fixtures.

[0015] The stopper device optionally includes two protruding mechanisms located on both the inner and outer sides of the vertical portion, and the protruding mechanisms are: A screw linear module attached to the aforementioned reversing frame, The system includes a push rod fixed to the screw linear module and facing the side of the vertical portion.

[0016] By employing 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 screw linear module ensure accurate control of the push rod's protruding length, and the adjustment of the inclination angle of the vertical section becomes more precise, thereby reliably offsetting thermal deformation caused by welding.

[0017] Optionally, the butt unit obtains a target inclination angle of the vertical portion based on the absolute value of the width difference between the outer weld joint and the inner weld joint calculated by the calculation unit, using the mapping relationship between the preset absolute value of the width difference between the outer weld joint and the inner weld joint and the inclination angle of the vertical portion, and the mapping relationship between the preset inclination angle of the vertical portion and the protruding length of the push rod. This allows the unit to obtain the actual protruding length of the push rod, control the protrusion of the push rod based on the actual protruding length of the push rod, and incline the vertical portion to the target inclination angle.

[0018] By adopting the above technical solution, the butt unit can directly convert welding joint width difference data into precise operating parameters of the push rod by recalling a dual mapping relationship between the absolute value of the width difference and the inclination angle of the vertical section, and between the inclination angle of the vertical section and the protruding length of the push rod. This further ensures that the control of the inclination angle of the vertical section is consistent with the quantifiable basis, accelerating the response speed from welding joint detection to butt operation. Combined with the simplification of the overall process, this further reduces time costs and cumulative error risks, and ensures structural accuracy and stability after mast welding.

[0019] Optionally, a temperature sensor may be provided on the push rod, and the control device is connected to the temperature sensor and used to monitor the temperature field of the welded joint, which is monitored in real time by the temperature sensor. If the temperature field of the welded joint exceeds a predetermined temperature, a compensated protrusion length is calculated based on the protrusion length of the push rod and a compensation coefficient, the compensated protrusion length is set as the actual protrusion length of the push rod, and the protrusion of the push rod is controlled based on the actual protrusion length of the push rod.

[0020] By adopting the above technical solution, the control device can timely detect a situation where thermal deformation due to abnormal temperature rise becomes serious during the welding process. When the temperature exceeds a predetermined value, it calculates a compensation protrusion length based on the current protrusion length of the push rod and the compensation coefficient at the corresponding temperature, and further dynamically adjusts the actual protrusion amount of the push rod, eliminates the static compensation limit during temperature variation of the preset mapping relationship, realizes real-time dynamic correction for thermal deformation caused by welding, avoids tilt angle deviation or insufficient deformation compensation due to abnormal temperature, and effectively solves the problem that it is difficult to cope with additional deformation caused by temperature change during the welding process in the conventional process.

[0021] Optionally, the cross member positioning device further positions a second cross member and is used to position both ends of the second cross member on opposite sides of two columns, and the control device is further used to control the two welding devices to perform welding simultaneously on both ends of the second cross member.

[0022] By adopting the above technical solution, the control device controls the two welding devices to perform welding simultaneously on both ends of the second cross member, avoids the problem that the process becomes redundant due to conventional step-by-step welding, reduces the cumulative error caused by multiple positionings, and also balances the welding heat input by synchronous welding at both ends, cancels out the thermal deformation at both ends of the second cross member with each other, reduces the risk of structural distortion caused by single-sided welding, further improves the welding accuracy and structural stability of the entire mast, and effectively solves the problem that it is difficult to adapt to various cross member structures and there is insufficient thermal deformation correction in the conventional process.

Advantages of the Invention

[0023] As described above, the present application includes at least one of the following beneficial technical effects.

[0024] 1. By combining the precise positioning of the column positioning device and crossmember positioning device in a single operation with the synchronous welding of the welding device, the step-by-step operation of pre-treatment spot welding and secondary welding in the conventional process is eliminated, significantly simplifying the process flow, reducing manpower, time, and space costs, and avoiding cumulative errors due to multiple positioning operations. This effectively improves the structural accuracy of the entire mast and fundamentally solves the problem of redundant steps and accumulated errors in the conventional process.

[0025] 2. Relying on the width data of the internal and external weld joints acquired by the weld joint detection device, the control device drives the abutment unit to precisely control the inclination angle of the vertical section by calling up a preset dual mapping relationship, thereby achieving proactive pre-emption and precise compensation for thermal deformation caused by welding. This solves the problem that conventional processes rely only on post-correction and are not good at dealing with structural deformation due to thermal stress, significantly reducing dimensional deviations and shape distortions of the mast, and ensuring the load-bearing performance and work safety of the forklift.

[0026] 3. The system features a movable stroke along the vertical extension direction of the butt joint and crossmember positioning device, and a dual positioning and synchronous welding design for the second crossmember, providing broad adaptability to masts with different specifications and crossmember distributions. This eliminates the need for frequent tooling changes, reducing mold change costs and machine downtime. Furthermore, synchronous welding balances heat input, further improving the consistency and stability of various mast welding applications and effectively solving the limitations of conventional fixed tooling's poor fit. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram of the structure of the forklift mast welding system in an embodiment of the present invention. [Figure 2] This is a magnified schematic view of area A in Figure 1. [Figure 3] This is a schematic diagram of a partial structure showing a stopper device in an embodiment of the present application. [Figure 4]This is a schematic diagram of the module of the forklift mast welding system in an embodiment of the present invention. [Modes for carrying out the invention]

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to Figures 1 to 4. Clearly, the embodiments described are only a selection of embodiments of this application, not all embodiments. All other embodiments obtained by a person skilled in the art without any creative work based on the embodiments of this application are all within the scope of protection of this application.

[0029] Referring to Figures 1 and 2, embodiments of the present application disclose a forklift mast welding system used for welding the outer mast or inner mast of a forklift mast, the outer mast or inner mast both comprising two parallel uprights 10 and a plurality of cross members connecting the two uprights 10. Here, the plurality of cross members comprises a plurality of first cross members 20 and a plurality of second cross members 30, the first cross members 20 and the second cross members 30 each comprising a horizontal portion 40 and two vertical portions 50. When the first cross member 20 is attached to the uprights 10, the bottom surfaces of the two vertical portions 50 of the first cross member 20 both abut the top surface of the uprights 10. The length of the horizontal portion 40 of the second cross member 30 is longer than the horizontal portion 40 of the first cross member 20. When the second cross member 30 is attached to the uprights 10, the two vertical portions 50 of the second cross member 30 are located on opposite sides of the uprights 10.

[0030] Referring to Figure 1, the forklift mast welding system includes a displacement machine 1, a column positioning device 2, a cross member positioning device 3, a weld joint detection device 4, abutment device 5, two welding devices 6, and a control device.

[0031] The displacement machine 1 mainly consists of a base, a reversing frame 11, and a reversing drive system, where the reversing frame 11 is a rigid frame structure. As a mounting base for the column positioning device 2 and the abutment device 5, the reversing frame 11 is connected to the base via a rotation axis and can be reversed around a horizontal axis to adjust the mast posture. The reversing drive system integrates a motor, a reduction gear, and transmission mechanisms such as rack and pinion and worm gear, allowing for precise control of the reversing angle and speed of the reversing frame 11, positioning the mast in an optimal position for easy operation of the welding device 6, thereby providing a stable and flexible support platform for high-precision welding of the forklift mast. The displacement machine 1 is prior art, and a detailed explanation is omitted.

[0032] The column positioning device 2 is attached to the inversion frame 11 and, by means of a mechanical jig or an air-driven mechanism, can precisely fix two parallel columns 10, ensuring that the columns 10 maintain a predetermined spacing and verticality during the welding process and providing a reference for positioning subsequent crossmember members. In one embodiment, the column positioning device 2 is a pair of first electric grippers, where each column 10 is supported and gripped by one of the first electric grippers, and the first electric grippers can adapt to the mounting and gripping requirements of columns 10 of different specifications, move synchronously with the inversion frame 11 by rigid connection, and ensure stability during the mast displacement process.

[0033] The crossmember positioning device 3 is used to position the first crossmember 20 and the second crossmember 30. In one embodiment, the crossmember positioning device 3 includes a robot arm and a second motorized clip attached to the robot arm. The crossmember positioning device 3 grips and moves either the first crossmember 20 or the second crossmember 30, positioning either the first crossmember 20 or the second crossmember 30 above the column 10 and aligning it with the column 10.

[0034] When the first cross member 20 is placed on the column 10, the bottom surfaces of both vertical portions 50 of the first cross member 20 abut against the top surface of the column 10. Due to discrepancies in processing accuracy during the cutting and pressing processes of the column 10 and the first cross member 20, the thermal expansion and contraction effects of the material cause unevenness of the edges, forming local differences in thickness or deviations in perpendicularity. As a result, the contact surfaces between the vertical portions 50 and the column 10 cannot be completely joined, causing a gap to exist between the bottom surfaces of the two vertical portions 50 of the first cross member 20 and the top surface of the column 10. In this application, this gap is defined as a welded joint. Here, the side of a vertical section 50 in the same first cross member 20 that faces another vertical section 50 is defined as the inner surface, and the welded joint between the inner surface and the top surface of the column 10 is an inner welded joint. The side of a vertical section 50 that is away from another vertical section 50 is defined as the outer surface, and the welded joint between the outer surface and the top surface of the column 10 is an outer welded joint. Due to factors such as deviations in processing accuracy and elastic deformation of the material, the vertical widths of the inner welded joint and the outer welded joint do not coincide.

[0035] The welding joint detection device 4 is used to detect the longitudinal width of the inner and outer welding joints. Referring to Figure 2, the welding joint detection device 4 includes a drive mechanism 41, a graphics processor mounted on the drive mechanism 41, and two industrial cameras 42. During detection, the two industrial cameras 42 are positioned on both sides of the vertical column 10. In one embodiment, the drive mechanism 41 may be two robot arms, each equipped with one industrial camera 42. The robot arms move to capture images of the inner and outer welding joints synchronously, moving the two industrial cameras 42 to both sides of the same vertical section 50. The graphics processor is connected to the industrial cameras 42 and is used to acquire images of the inner and outer welding joints captured by the industrial cameras 42. The graphics processor analyzes the images using an edge detection algorithm or the like to accurately calculate the longitudinal width of the inner and outer welding joints, providing a numerical basis for subsequent temporary tilt control.

[0036] The abutment device 5 is slidably mounted on the reversing frame 11. Two abutment devices 5 are provided, corresponding one-to-one with the two upright columns 10 and having a movable stroke along the extension direction of the upright columns 10. A drive motor for driving the movement of the abutment device 5 is mounted on the reversing frame 11. Referring to Figure 3, the abutment device 5 includes projection mechanisms located on both the inner and outer sides of the vertical section 50, each projection mechanism including a screw linear module 51 and a push rod 52 fixed to the screw linear module 51. The push rod 52 faces the inner and outer surfaces of the vertical section 50, and the screw linear module 51 is mounted on the reversing frame 11 and can drive the push rod 52 to move horizontally, thereby achieving abutment against the bottom side edge of the vertical section 50. The butt joint device 5 is positioned to have a vertical movable stroke, and the point of application of the push rod 52 can be adjusted according to the position of the first cross member 20. By controlling the protruding length of the push rod 52, the inclination angle of the vertical portion 50 can be precisely controlled, thereby actively counteracting thermal deformation caused by welding.

[0037] Both welding devices 6 include a robotic arm and a welding torch attached to the robotic arm, and are positioned to the side of the displacement machine 1. When welding the first cross member 20, they are responsible for synchronous welding of the same vertical section 50 and the outer and inner welded joints of the vertical column 10, and when welding the second cross member 30, they are responsible for synchronous welding of the two vertical sections 50 of the second cross member 30 and the vertical column 10. The robotic arm is an industrial 6-axis robotic arm, and its movement trajectory and welding parameters can be dynamically adjusted according to the forklift mast (outer mast or inner mast). Combined with the mast's inversion position, this enables omnidirectional automatic welding and ensures consistent quality of the welded joints.

[0038] Referring to Figure 4, the control unit is connected to a weld joint detection device 4, abutment device 5, and two welding devices 6, and includes an acquisition unit, a comparison unit, a calculation unit, abutment unit, and a welding unit. First, the acquisition unit collects width data of the outer and inner weld joints from the weld joint detection device 4, the comparison unit compares the sizes of the two, and the calculation unit calculates the difference between them (ΔW = width of outer weld joint - width of outer weld joint) to obtain the absolute value of the width difference (|ΔW|). Subsequently, the abutment unit recalls the preset dual mapping relationships of "absolute value of width difference - vertical section inclination angle" and "vertical section inclination angle - push rod protrusion length" according to the width relationship between the outer and inner weld joints and the value of |ΔW|, and controls the abutment device 5 to perform inward and outward abutment against the bottom end of the vertical section 50, causing the vertical section 50 to generate an accurate inclination angle relative to the vertical column 10.

[0039] If the width of the outer welded joint is greater than the width of the inner welded joint, the butt joint device 5 is controlled to abut the bottom end of the vertical section 50 outward based on the absolute value of the width difference between the outer welded joint and the inner welded joint, so that the vertical section 50 has a non-vertical state inclined inward at a target angle relative to the vertical column 10. If the width of the outer welded joint is less than the width of the inner welded joint, the butt joint device 5 is controlled to abut the bottom end of the vertical section 50 inward based on the absolute value of the width difference between the outer welded joint and the inner welded joint, so that the vertical section 50 has a non-vertical state inclined outward at a target angle relative to the vertical column 10.

[0040] The control device achieves precise control based on two layers of preset mapping relationships: a mapping relationship between the absolute value of the width difference and the inclination angle of the vertical section (determining the angle), and a mapping relationship between the inclination angle of the vertical section and the push rod protrusion length (converting to mechanical parameters). Based on these mapping relationships, the push rod protrusion length is derived from the absolute value of the width difference, and the operation of the push rod 52 is further controlled to incline the vertical section 50 to the target inclination angle. Finally, after the vertical section 50 is adjusted to the predetermined position, the welding unit synchronously triggers the two welding devices 6 to complete the welding work on the inner and outer weld joints.

[0041] It should be understood that the mapping relationship between the absolute value of the width difference between the outer and inner welded joints and the inclination angle of the vertical section can be obtained by integrating historical data from actual production. First, successful welding data accumulated over long-term production of the same type of welding equipment is collected, and the absolute value of the width difference between the outer and inner welded joints (|ΔW|) and the actual inclination angle (θ) of the vertical section 50 relative to the column 10 after welding are extracted to form a basic parameter library. Next, empirical calibration is performed on the θ values ​​of typical |ΔW| intervals, supplementing and correcting fuzzy parameters in the historical data. Finally, verification is performed on an actual welding platform through trial and error experiments. For a specific |ΔW| value, the θ value is set as the initial inclination angle of the vertical section 50 before welding, and the inclination angle is adjusted stepwise based on the quality detection results of the welded joint (e.g., flaw detection pass rate, uniformity of penetration depth). After multiple iterations, the optimal θ value corresponding to the |ΔW| value is determined, forming an empirical mapping table with practical application in construction.

[0042] Based on the length of the moment arm from the point of application of the push rod 52 to the vertical section 50, the theoretical value of the push rod protrusion length corresponding to different inclination angles is calculated using trigonometric functions. Furthermore, the force acting on the push rods 52 with different protrusion lengths is applied by the butt joint device 5, the inclination angle is measured by the inclination angle sensor, the measured value is compared with the theoretical value to form an initial mapping table, and finally, the corresponding parameters of push rod protrusion length and inclination angle are fine-tuned according to the actual welding conditions. By accumulating and optimizing production data from multiple lots, a stable and reliable mapping relationship is formed.

[0043] In one embodiment, a temperature sensor is provided on the push rod 52, and a control device is connected to the temperature sensor and used to monitor the temperature field of the welded joint, which is monitored in real time by the temperature sensor. If the temperature field of the welded joint exceeds a predetermined temperature, a compensated protrusion length is calculated based on the protrusion length of the push rod and a compensation coefficient, the compensated protrusion length is set as the actual protrusion length of the push rod 52, and the protrusion of the push rod 52 is controlled based on the actual protrusion length of the push rod 52.

[0044] In the welding process, temperature is a core variable that affects the thermal deformation of the material. Changes in the temperature field of the welding area directly determine the distribution and release of thermal stress. If the temperature is too high, the amount of thermal expansion of the material increases, and shrinkage deformation becomes severe after cooling. On the other hand, if the temperature is too low, it may overcompensate for the preset inclination angle, and both disrupt the original deformation cancellation balance. Temperature detection is necessary to capture the dynamic effect of temperature fluctuations on thermal deformation in the welding process in real time. Because there are differences in the thermal expansion coefficient and shrinkage rate of the material at different temperatures, even if the initial width difference of the welded joint is the same, temperature changes cause the actual amount of deformation to deviate from the expected value of the preset mapping relationship. By performing compensation calculations based on temperature, the protrusion length of the pushrod can be corrected by introducing a temperature coefficient for the deviation between the real-time temperature and a predetermined reference temperature, and the inclination angle of the vertical section 50 can be dynamically adapted to the thermal deformation characteristics at the current temperature. This avoids undercompensation or overcompensation due to temperature fluctuations, thereby maintaining an accurate deformation cancellation effect throughout the entire welding process and further improving the dimensional accuracy and structural stability of the mast weld.

[0045] Specifically, the compensation coefficient is determined based on material thermal deformation rules and a large amount of test data. Control tests are conducted on the mast and the first cross member 20 at different welding temperature intervals (covering the temperature fluctuation range that can occur in actual production). The difference between the actual thermal deformation of the welded joint at each temperature and the theoretical deformation is recorded. This is then combined with the effect of the pushrod protrusion length on the inclination angle, and the compensation coefficient is determined by fitting a relationship curve between the temperature deviation (difference between real-time temperature and a predetermined reference temperature) and the compensation amount.

[0046] In this description, unless otherwise specifically defined or limited, the terms "attachment" and "connection" should be understood in a broad sense. For example, they may be fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected via an intermediate medium, or internally connected to two elements. A person skilled in the art will be able to understand the specific meaning of these terms in this application depending on the specific circumstances.

[0047] In the description of this application, it should be understood that the orientations or positional relationships indicated by terms such as "center," "vertical," "horizontal," "length," "width," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "peak," "bottom," "inside," and "outside" are based on the orientations or positional relationships shown in the drawings. They are merely for the purpose of facilitating and simplifying the description of this application, and do not indicate or suggest that the shown device or element has a specific orientation or must be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting this application. Furthermore, the terms "first" and "second" are used simply for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, features limited by "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "multiple" is two or more unless otherwise clearly and specifically defined.

[0048] All of the above are preferred embodiments of the present application and do not limit the scope of protection thereunder. Therefore, any modifications made based on the structure, shape, and principle of the present application should all be included within the scope of protection. [Explanation of Symbols]

[0049] 10... Column, 20... First cross member, 30... Second cross member, 40... Horizontal section, 50... Vertical section, 1... Displacement machine, 11... Inversion frame, 2... Column positioning device, 3... Cross member positioning device, 4... Weld joint detection device, 41... Drive mechanism, 42... Industrial camera, 5... Butt device, 51... Screw linear module, 52... Push rod, 6... Welding device.

Claims

1. A displacement machine (1) on which an inverting frame (11) is positioned, A column positioning device (2) is attached to the inverting frame (11) for positioning two parallel columns (10), A cross member positioning device (3) is provided to position the first cross member (20), which includes a horizontal section (40) and two vertical sections (50), and to bring the bottom surface of the vertical section (50) into contact with the top surface of the upright column (10), A welding joint detection device (4) for detecting the width in the vertical direction of an inner welding joint and an outer welding joint, wherein the inner welding joint is defined as the vertical distance between the inner surface of the vertical portion (50) in the lateral direction and the vertical column (10) before welding, and the outer welding joint is defined as the vertical distance between the outer surface of the vertical portion (50) in the lateral direction and the vertical column (10) before welding, A butt device (5) is attached to the inverting frame (11) and faces the inner and outer surfaces of the vertical portion (50), Each of the two welding devices (6) located to the side of the displacement machine (1) includes a robot arm and a welding torch attached to the robot arm, The control device is connected to the welding joint detection device (4), the butt device (5), and the two welding devices (6), and calculates the width difference between the outer welding joint and the inner welding joint based on the width of the inner welding joint and the outer welding joint, and controls the butt device (5) to abut the bottom end of the vertical section (50) inward against the outer surface of the vertical section (50) or to abut the bottom end of the vertical section (50) outward against the inner surface of the vertical section (50) based on the width difference, so that the vertical section (50) has a non-vertical state inclined outward or inward with respect to the vertical column (10), and subsequently controls the two welding devices (6) to perform welding on the outer welding joint and the inner welding joint simultaneously. A forklift mast welding system characterized by the following features.

2. The welding joint detection device (4) includes a drive mechanism (41), a graphics processor mounted on the drive mechanism (41), and two industrial cameras (42). The drive mechanism (41) drives the two industrial cameras (42) to move on both the inner and outer sides of the vertical section (50) to capture images of the inner and outer welding joints. The graphics processor is connected to the industrial camera (42) and is used to acquire images of the inner and outer weld joints captured by the industrial camera (42), and to acquire the width of the outer and inner weld joints. The forklift mast welding system according to claim 1.

3. The control device is An acquisition unit for obtaining the width of the outer welded joint and the inner welded joint, A comparison unit for comparing the widths of the outer welded joint and the inner welded joint, A calculation unit for calculating the absolute value of the aforementioned width difference, A butt unit for abutting a vertical section (50) to abut the bottom end of the vertical section (50) outward when the width of the outer welded joint is greater than the width of the inner welded joint, based on the absolute value of the width difference, so that the vertical section (50) has a non-vertical state inclined inward at a target angle relative to the upright column (10), and for abutting a vertical section (50) to abut the bottom end of the vertical section (50) inward when the width of the outer welded joint is less than the width of the inner welded joint, based on the absolute value of the width difference, so that the vertical section (50) has a non-vertical state inclined outward at a target angle relative to the upright column (10), The welding unit includes, after the butt joint device (5) butts the bottom end of the vertical portion (50), a welding unit for controlling the two welding devices (6) to simultaneously weld the outer weld joint and the inner weld joint, The forklift mast welding system according to feature 2.

4. The abutment device (5) and the cross member positioning device (3) are both arranged to have a movable stroke along the extending direction of the vertical column (10). The forklift mast welding system according to feature 3.

5. The stopper device (5) includes two protruding mechanisms located on both the inner and outer sides of the vertical portion (50), and the protruding mechanisms are A screw linear module (51) attached to the inverting frame (11), The screw linear module (51) is fixed to the screw linear module (51) and includes a push rod (52) that faces the side surface of the vertical portion (50), The forklift mast welding system according to feature 3.

6. The abutment unit obtains a target inclination angle of the vertical portion (50) based on the absolute value of the width difference between the outer welded joint and the inner welded joint calculated by the calculation unit, using the absolute value of the width difference between the outer welded joint and the inner welded joint, thereby obtaining the actual inclination length of the push rod (52), and controlling the protrusion of the push rod (52) based on the actual inclination length of the push rod (52) to inclin the vertical portion (50) to the target inclination angle. The forklift mast welding system according to feature 5.

7. A temperature sensor is provided on the push rod (52), and the control device is connected to the temperature sensor and used to monitor the temperature field of the welded joint, which is monitored in real time by the temperature sensor. When the temperature field of the welded joint exceeds a predetermined temperature, the control device calculates a compensated protrusion length based on the protrusion length of the push rod (52) and a compensation coefficient, sets the compensated protrusion length as the actual protrusion length of the push rod (52), and controls the protrusion of the push rod (52) based on the actual protrusion length of the push rod (52). The forklift mast welding system according to feature 6.

8. The cross member positioning device (3) is used to further position the second cross member (30) and to position both ends of the second cross member (30) on opposite sides of the two vertical columns (10), and the control device is used to control the two welding devices (6) to simultaneously weld both ends of the second cross member (30). The forklift mast welding system according to claim 1.

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