Precision keeping device and method for welding tractor

Abstract

The invention discloses a welding tractor precision keeping device and method, and solves the technical problems that in the prior art, the fault processing time of a side guide wheel is long, and a normal production plan is affected. A welding tractor precision keeping device is characterized by comprising a support; the telescopic assembly is installed on the support, and the telescopic assembly is provided with a jacking wheel used for jacking the side portion of the welding trolley; the driving part is connected to the telescopic assembly; the driving part is used for driving the telescopic assembly to move in the width direction of the welding trolley so that the welding trolley can return to the original position. The retaining device can temporarily replace a side guide wheel, and smooth production is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of welding trolley, and particularly relates to a welding trolley precision maintaining device and method. BACKGROUND

[0002] Large resistance lap welding machines are mostly used in continuous production lines, such as cold rolling production lines or continuous annealing production lines, etc. The production rhythm is fast. The resistance lap welding machine comprises a welding trolley and a track. The welding trolley walks along the track in the width direction of the strip steel, thereby driving the welding wheel to move in the width direction of the strip steel, so as to realize the welding of the lap joint position of the tail of the front strip steel and the head of the rear strip steel.

[0003] In the welding process of the front and rear strip steels, the walking precision of the welding wheel of the welding trolley is crucial to obtain a good weld. The welding wheel is installed on the welding trolley, so the walking track of the welding trolley is a key factor to ensure the quality of the weld.

[0004] The welding trolley is provided with a side guide wheel for adjusting the walking track of the welding trolley. When the side guide wheel fails or the precision error is large, and the track of the welding trolley is abnormal, the troubleshooting and processing time is long, which will affect the normal production plan, and even cause serious production failures such as broken strip caused by poor welds. SUMMARY

[0005] To solve the technical problem that the side guide wheel fault processing time is long and affects the normal production plan, the application provides a welding trolley precision maintaining device and method.

[0006] In the first aspect of the application, a welding trolley precision maintaining device is provided, comprising:

[0007] a support;

[0008] a telescopic assembly installed on the support, the telescopic assembly being provided with a top wheel for clamping the side of the welding trolley;

[0009] a driving member connected to the telescopic assembly;

[0010] The driving member is used to drive the telescopic assembly to move in the width direction of the welding trolley, so as to return the welding trolley to the original position.

[0011] In some embodiments, the telescopic assembly comprises a first connecting rod, a second connecting rod and a mounting member. The first connecting rod and the second connecting rod are provided in pairs and correspondingly. One end of the first connecting rod is hinged to the support, and the other end is hinged to the corresponding second connecting rod through a hinge shaft. Both of the second connecting rods are hinged to the mounting member, and the top wheel is rotatably installed on the mounting member.

[0012] The driving element is used to drive the other ends of the two first links to move closer or further apart.

[0013] In some embodiments, the driving element is a threaded rod having two threaded segments with opposite thread directions, the two threaded segments being arranged one-to-one with two hinge shafts, and the threaded segments being threadedly connected to the corresponding hinge shafts.

[0014] In some embodiments, the drive element is a threaded rod having two threaded segments with opposite thread directions; the telescopic assembly further includes two connecting blocks, with the two threaded segments threadedly connected to the two connecting blocks respectively, and the connecting blocks being close to the hinge axis;

[0015] The two connecting blocks are respectively installed on the two first connecting rods; or,

[0016] The two connecting blocks are respectively installed on the two second connecting rods.

[0017] In some embodiments, the drive element further includes a handle connected to the threaded rod, the handle being located at the top of the threaded rod.

[0018] In some embodiments, the support includes a base and a top block, the top block being mounted on the base and having an adjustable height, the top surface of the top block being pressed against the bottom surface of the welding trolley's track.

[0019] In some embodiments, there are two top blocks, which are located at the top and bottom of the base, respectively. The distance between the two top blocks is adjustable, and the two top blocks are respectively pressed against the bottom surface of the welding trolley track and the ground.

[0020] In some embodiments, the base has a side for engaging with the base of the welding trolley; the top wheel and the side are disposed opposite to each other along the width direction of the welding trolley.

[0021] In a second aspect of this application, a method for maintaining the precision of a welding carriage is provided, comprising the following steps:

[0022] The dimensions of multiple points of shear scrap from the tail of the previous coil and the head of the next coil are obtained along the running direction of the strip, and the multiple points are distributed sequentially along the width direction of the strip.

[0023] When the width difference between any two adjacent points is greater than the first set value and the welding wheel of the welding carriage is located in the middle of the two clamps of the welding carriage, or when the width difference between any two adjacent points is not greater than the first set value and the welding wheel of the welding carriage is not located in the middle of the two clamps of the welding carriage, the holding device of the first aspect is set on one side of the welding carriage, and the top wheel is pressed against the side of the welding carriage. The welding carriage is moved along the width direction of the welding carriage by the driving component so that the traveling direction of the welding wheel is collinear with the shearing cut of the tail of the previous coil of strip and the head of the next coil of strip.

[0024] The welding trolley is started, and the welding wheel welds the overlap position of the tail of the previous coil of strip and the head of the next coil of strip.

[0025] In some implementations, the following steps are also included:

[0026] During the welding process of the welding wheel at the lap joint, the position of the weld mark on the welding wheel is obtained;

[0027] When the weld mark is off-center from the wheel surface, the welding carriage is moved along the width of the welding carriage by the drive component until the weld mark is located in the center of the wheel surface.

[0028] The welding carriage precision holding device provided according to the embodiments of this application includes a bracket, a telescopic assembly, and a driving component; the telescopic assembly is mounted on the bracket and is provided with a top wheel for pressing against the side of the welding carriage; the driving component is connected to the telescopic assembly; wherein, the driving component is used to drive the telescopic assembly to move along the width direction of the welding carriage so that the welding carriage returns to its original position.

[0029] In the event of a malfunction in the side guide wheels of the welding carriage or a significant error in adjustment accuracy, the telescopic component of the retaining device can be used to adjust the forward direction of the welding carriage, allowing it to return to its original position and improving welding precision. Because the retaining device has a simple structure, only the bracket needs to be fixed to adjust the direction of the welding carriage, providing time for the maintenance of the side guide wheels. Even during the maintenance of the side guide wheels, the welding precision of the welding carriage can still be maintained, ensuring the smooth implementation of the production plan. Attached Figure Description

[0030] Figure 1 A schematic diagram of the structure of the welding carriage and the holding device of this application is shown.

[0031] Figure 2 A schematic diagram of the structure of the welding carriage and the holding device is shown.

[0032] Figure 3 It shows Figure 2 A schematic diagram of the holding device.

[0033] Figure 4 It shows Figure 3 Side view of the bracket in the middle.

[0034] Explanation of reference numerals in the attached figures:

[0035] 11-Car body, 12-Base, 13-Rail, 14-Support wheel

[0036] 20-Retaining device, 210-Bracket, 211-Base, 212-Top block, 220-Telescopic assembly, 221-First link, 222-Second link, 223-Mounting component, 224-Top wheel, 230-Drive component, 231-Threaded rod, 232-Handle. Detailed Implementation

[0037] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] According to a first aspect of this application, a welding carriage precision maintaining device is provided, which can improve the welding precision of the welding carriage.

[0039] Please see Figure 1 The welding trolley includes a base, rails, and a trolley body. Two bases are provided, spaced apart along the width of the trolley body. The gap between the two bases forms a channel for the trolley body to move. Rails are provided on the adjacent sides of the two bases. Support wheels are provided on both sides of the trolley body along the width direction. The support wheels are rolled and connected to the rails, thereby enabling the trolley body to move along the width direction of the strip steel to weld the joint between the tail of the previous coil of strip steel and the head of the next coil of strip steel.

[0040] The welding carriage also includes clamps, double cutters, and welding wheels. The clamps are mounted on the frame of the production line and are used to clamp and position the tail of the previous coil of strip and the head of the next coil of strip. The double cutters and welding wheels are both mounted on the carriage body. They cut the tail of the previous coil of strip and the head of the next coil of strip after clamping and positioning. Then, after overlapping according to the set overlap amount, the welding wheels complete the welding to obtain a good weld.

[0041] Please see Figure 2 as well as Figure 3The welding carriage precision holding device provided in this application includes a bracket, a telescopic assembly, and a driving component; the telescopic assembly is mounted on the bracket and is provided with a top wheel for pressing against the side of the welding carriage; the driving component is connected to the telescopic assembly; wherein, the driving component is used to drive the telescopic assembly to move along the width direction of the welding carriage so that the welding carriage returns to its original position.

[0042] The bracket provides the mounting base for the telescopic assembly and the drive mechanism. The telescopic assembly is extendable, allowing the top wheel to provide propulsion for the welding carriage to move along one side of its width. Since the welding carriage reciprocates along its length, and the holding device can only extend and retract along the width of the welding carriage, the top wheel reduces the friction between the telescopic assembly and the welding carriage. The drive mechanism provides the propulsion force to extend and retract the telescopic assembly along the width of the welding carriage, adjusting the carriage's forward direction so that the direction of travel of the welding wheel is parallel to the width direction of the strip.

[0043] In the event of a malfunction in the side guide wheels of the welding carriage or a significant error in adjustment accuracy, the telescopic component of the retaining device can be used to adjust the forward direction of the welding carriage, allowing it to return to its original position and improving welding accuracy. Because the retaining device has a simple structure, only the bracket needs to be fixed to adjust the direction of the welding carriage, providing time for the maintenance of the side guide wheels and ensuring that the welding accuracy of the welding carriage is maintained even during maintenance.

[0044] For the stent, please refer to some embodiments. Figure 3 The bracket may include a base and a top block. The top block is mounted on the base and its height is adjustable. The top surface of the top block presses against the bottom surface of the welding trolley's track, thereby fixing the bracket. By using the top block to press against the bottom surface of the track, and the bottom of the bracket directly acting on the ground to fix the bracket—that is, fixing the bracket by upper and lower pressing and limiting—the disassembly and reassembly of the bracket are more convenient and flexible, improving the efficiency of adjusting the traveling direction of the welding trolley. In other embodiments, the bracket may also be mounted on a base or a connecting seat, which can also achieve the fixation of the holding device. The installation method can be screwed or welded; this application is not limited to either.

[0045] In some embodiments, please refer to Figure 3 as well as Figure 4 The device has two top blocks, located at the top and bottom of the base respectively. The distance between the two top blocks is adjustable, and the two top blocks are respectively pressed against the bottom surface of the welding trolley's track and the ground. The two height-adjustable top blocks are suitable for welding trolleys with limited space under the track as well as those with ample space, thus expanding the application range of the holding device and making it more versatile.

[0046] Regarding the connection structure between the top block and the base, in some embodiments, the base is provided with a threaded hole, and the bracket also includes a threaded post connected to the top block. The threaded post is threaded into the threaded hole, thereby enabling continuous adjustment of the height of the top block and the distance between the two top blocks. In other embodiments, the base is provided with a threaded post, the top block is provided with a threaded hole, and the threaded post is threaded into the threaded hole, which also enables continuous adjustment of the height of the top block and the distance between the two top blocks.

[0047] In some embodiments, the support is a telescopic cylinder, such as a hydraulic cylinder, pneumatic cylinder, or electric cylinder. The fixed end of the telescopic cylinder is pressed against the ground, and the telescopic end is pressed against the bottom surface of the track, which can also achieve the fixation of the support.

[0048] In some embodiments, the base has a side surface for engaging with the base of the welding carriage, and the top wheel is positioned opposite to the side surface along the width direction of the welding carriage. The base having a side surface for engaging with the base allows for a close fit between the base and the base, improving the stability of the telescopic assembly during its extension and retraction along the width direction of the carriage. In other embodiments, the base and the base may also be spaced apart along the width direction of the carriage, allowing for adjustment of the carriage's travel direction so that the travel direction of the welding wheel is parallel to the width direction of the strip steel.

[0049] In some embodiments, please refer to Figure 3 The telescopic assembly may include a first link, a second link, and a mounting component. There are two first links and two second links, which are arranged in a one-to-one correspondence. One end of the first link is hinged to the bracket, and the other end is hinged to the corresponding second link through a hinge shaft. Both second links are hinged to the mounting component. The top wheel is rotatably mounted on the mounting component. The driving component is used to drive the other ends of the two first links to move closer or further apart.

[0050] Both first links are hinged to the base of the bracket, and both second links are hinged to the mounting component. The first and second links are hinged together, allowing this linkage mechanism to fold or extend along the width of the vehicle body, thus enabling the top wheel to retract along the width of the vehicle body. The linkage mechanism offers good stability and structural flexibility. In other embodiments, the telescopic assembly can also employ other telescopic structures, such as cylinders or electric cylinders, to achieve reciprocating movement of the top wheel along the width of the vehicle body.

[0051] In some embodiments, the driving component is a threaded rod with two threaded segments having opposite thread directions. Each threaded segment corresponds to one of two hinge shafts, and the threaded segments are threadedly connected to their respective hinge shafts. Since the two threaded segments of the threaded rod have opposite thread directions, rotation of the threaded rod allows the two hinge shafts to move closer or further apart, enabling the linkage mechanism to extend or fold, thereby achieving the extension and retraction of the top wheel along the width direction of the vehicle body.

[0052] In other embodiments, the driving component is a threaded rod with two threaded segments in opposite directions. The telescopic assembly also includes two connecting blocks, with the two threaded segments threadedly connected to the two connecting blocks respectively. The connecting blocks are located near the hinge shaft and are respectively mounted on two first connecting rods. Rotation of the threaded rod causes the two connecting blocks to move closer to or back to each other, thereby extending or folding the linkage mechanism and thus enabling the top wheel to extend or retract along the width direction of the vehicle body. Alternatively, in other embodiments, the two connecting blocks can also be respectively mounted on two second connecting rods. Rotation of the threaded rod can also cause the two connecting blocks to move closer to or back to each other, thereby extending or folding the linkage mechanism and thus enabling the top wheel to extend or retract along the width direction of the vehicle body.

[0053] In some embodiments, please refer to Figure 3 The retaining device may also include a handle connected to the threaded rod, with the handle located at the top of the threaded rod. This allows the operator to hold the handle from above and rotate the threaded rod to fold or retract the linkage mechanism, making operation convenient.

[0054] Based on the same technical concept as the first aspect, the second aspect of this application provides a method for maintaining the precision of a welding carriage, thereby improving the welding precision of the welding carriage.

[0055] The method of maintaining this application includes the following steps:

[0056] S1. Obtain the dimensions of multiple points of shear scrap from the tail of the previous coil and the head of the next coil along the running direction of the strip, with the multiple points distributed sequentially along the width direction of the strip.

[0057] S2. When the width difference between any two adjacent points is greater than the first set value and the welding wheel of the welding carriage is located in the middle of the two clamps of the welding carriage, or when the width difference between any two adjacent points is not greater than the first set value and the welding wheel of the welding carriage is not located in the middle of the two clamps of the welding carriage, the holding device of any embodiment of the first aspect is provided on one side of the welding carriage, and the top wheel is pressed against the side of the welding carriage. The welding carriage is moved along the width direction of the welding carriage by the driving member so that the traveling direction of the welding wheel is collinear with the shearing cut of the tail of the previous coil of strip and the head of the next coil of strip.

[0058] S3. Start the welding trolley and weld the overlap position of the tail of the previous coil of strip and the head of the next coil of strip.

[0059] The low welding precision of the welding carriage is essentially due to the welding wheel's travel direction being inconsistent with the width direction of the strip steel, even though the welding wheel is mounted on the welding carriage. During the shearing process of the tail of the previous coil of strip steel and the head of the next coil, the production line clamps hold the strip steel, and the double-cutting shears on the welding carriage cut the strip steel. Therefore, if the welding carriage's travel direction is inconsistent with the width direction of the strip steel, there will also be a deviation between the double-cutting shears mounted on the welding carriage and the target position. Consequently, the cut scrap will not be a regular rectangle, but a trapezoid. In other words, when the welding carriage deviates from its course, the width dimension of the scrap along the width direction of the strip steel (the dimension along the length direction of the strip steel) varies at different points, for example, gradually increasing or decreasing. Therefore, if the width dimension of the feed material fluctuates significantly—that is, the width difference between any two adjacent points is greater than the first set value—the welding wheel of the welding carriage is considered to be severely misaligned, resulting in low strip steel welding precision.

[0060] Another scenario is that the width difference between any two adjacent points of the waste cut by the double cutter is no greater than the first set value, but the welding accuracy of the welding wheel is still low. This means that the clamps and double cutters are in the target position, but the car body and welding wheel are off-center. In this case, you can check whether the welding wheel is set in the middle of the two clamps. If the welding wheel is not in the middle of the two clamps, it indicates that the welding wheel has deviated and the welding accuracy of the strip steel is low.

[0061] If either of the above two situations is discovered before the welding wheel has been welded, the holding device is placed on one side of the welding carriage, and the top wheel is pressed against the side of the carriage body. By rotating the threaded rod, the carriage body moves along the width direction of the strip steel while changing its own width direction, so that the moving direction of the welding wheel is consistent with the width direction of the strip steel, thereby improving the welding accuracy.

[0062] In practice, the placement of the holding device on either side of the welding carriage's width can be determined based on the width variation of the scrap at the tail of the previous coil and the width variation of the scrap at the head of the next coil. Similarly, the placement of the holding device on either side of the welding wheel's clamps determines its position within the welding carriage's width; and the placement of the holding device on the welding wheel's weld mark, based on its axial orientation, also determines its position within the welding carriage's width.

[0063] In some embodiments, the holding method may further include the following steps:

[0064] During the welding process at the lap joint of the welding wheels, the location of the weld mark on the welding wheel is obtained;

[0065] When the weld mark is off-center from the wheel surface, the welding carriage is moved along the width of the welding carriage by the drive component until the weld mark is in the center of the wheel surface.

[0066] During the welding process of the welding wheel, if it is found that the weld mark on the wheel surface is not in the exact center of the axial direction of the welding wheel, the driving component is used to adjust the walking direction of the vehicle body and the welding wheel so that the weld mark on the welding wheel is located in the axial center of the wheel surface, thereby improving the welding accuracy.

[0067] The welding carriage precision maintenance device and method provided in this application have at least the following advantages:

[0068] (1) The holding device provided in this application can temporarily replace the side guide wheel without affecting the production line operation status, restore the welding accuracy of the welding wheel of the welding carriage, avoid the lag of the side guide wheel failure expanding to the point of being unable to weld, and the timeliness problem of the production line being unable to operate normally due to the long time of handling the failure. It provides technicians with a practical and operable solution for accuracy monitoring and accuracy recovery during production line operation.

[0069] (2) The holding method provided in this application preliminarily judges the welding accuracy by the size of the waste and the position of the welding wheel, and when it is judged that the welding wheel has a walking deviation, the holding device is used to adjust the walking direction of the welding wheel to improve the welding accuracy.

[0070] (3) The welding accuracy is judged a second time by the position of the welding mark on the welding wheel during the movement of the welding wheel. If the position of the welding mark is not in the middle of the wheel surface, the walking direction of the welding wheel is adjusted by the holding device to improve the welding accuracy.

[0071] (4) The holding device provided in this application can be operated during production to restore and maintain the accuracy of the welding carriage without removing the side guide wheel, thus minimizing the impact of the entire process on the production line.

[0072] (5) Taking into account the inconvenience of precision measurement during production line operation and the inability to replace the side guide wheel due to time constraints, the implementation of this invention can safely and conveniently detect abnormalities in the trolley's running trajectory. At the same time, it can restore the welding trolley to the corresponding precision without affecting the production line operation. This avoids the lag in discovering the side guide wheel failure only when it becomes impossible to weld, as well as the timeliness problem of the production line being unable to operate normally due to the long time required to handle the failure. It provides technicians with a practical and operable solution for precision monitoring and precision recovery during production line operation.

[0073] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0074] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0075] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0076] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0077] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A precision-maintaining device for a welding carriage, characterized in that, include: support; A telescopic assembly is mounted on the bracket, and the telescopic assembly is provided with top wheels for pressing against the side of the welding trolley; A drive unit is connected to the telescopic assembly; The driving component is used to drive the telescopic assembly to move along the width direction of the welding carriage so that the welding carriage returns to its original position.

2. The precision maintaining device for welding carriage according to claim 1, characterized in that, The telescopic assembly includes a first link, a second link, and a mounting component. There are two of each of the first and second links, and they are arranged in a one-to-one correspondence. One end of the first link is hinged to the bracket, and the other end is hinged to the corresponding second link through a hinge shaft. Both second links are hinged to the mounting component, and the top wheel is rotatably mounted on the mounting component. The driving element is used to drive the other ends of the two first links to move closer or further apart.

3. The precision maintaining device for welding carriage according to claim 2, characterized in that, The driving component is a threaded rod, which has two threaded segments with opposite thread directions. The two threaded segments are arranged in a one-to-one correspondence with two hinge shafts, and the threaded segments are threadedly connected to the corresponding hinge shafts.

4. The precision maintaining device for welding carriage according to claim 2, characterized in that, The driving component is a threaded rod with two threaded segments having opposite thread directions; the telescopic assembly also includes two connecting blocks, with the two threaded segments threadedly connected to the two connecting blocks respectively, and the connecting blocks being close to the hinge axis; The two connecting blocks are respectively installed on the two first connecting rods; or, The two connecting blocks are respectively installed on the two second connecting rods.

5. The welding carriage precision maintaining device according to claim 3 or 4, characterized in that, The drive unit also includes a handle connected to the threaded rod, the handle being located at the top of the threaded rod.

6. The precision-maintaining device for the welding carriage according to any one of claims 1-4, characterized in that, The support includes a base and a top block. The top block is installed on the base and its height is adjustable. The top surface of the top block is pressed against the bottom surface of the welding trolley track.

7. The precision maintaining device for welding carriage according to claim 6, characterized in that, The top block is provided in two parts, which are located at the top and bottom of the base respectively. The distance between the two top blocks is adjustable, and the two top blocks are respectively pressed against the bottom surface of the welding trolley track and the ground.

8. The precision maintaining device for welding carriage according to claim 6, characterized in that, The base has a side for engaging with the base of the welding trolley; the top wheel and the side are arranged opposite to each other along the width direction of the welding trolley.

9. A method for maintaining the precision of a welding trolley, characterized in that, Includes the following steps: The dimensions of multiple points of shear scrap from the tail of the previous coil and the head of the next coil are obtained along the running direction of the strip, and the multiple points are distributed sequentially along the width direction of the strip. When the width difference between any two adjacent points is greater than the first set value and the welding wheel of the welding carriage is located in the middle of the two clamps of the welding carriage, or when the width difference between any two adjacent points is not greater than the first set value and the welding wheel of the welding carriage is not in the middle of the two clamps of the welding carriage, the holding device according to any one of claims 1-8 is disposed on one side of the welding carriage, and the top wheel is pressed against the side of the welding carriage. The welding carriage is moved along the width direction of the welding carriage by the driving member so that the traveling direction of the welding wheel is collinear with the shearing cut of the tail of the previous coil of strip and the head of the next coil of strip. The welding trolley is started, and the welding wheel welds the overlap position of the tail of the previous coil of strip and the head of the next coil of strip.

10. The method for maintaining the precision of a welding carriage according to claim 9, characterized in that, It also includes the following steps: During the welding process of the welding wheel at the lap joint, the position of the weld mark on the welding wheel is obtained; When the weld mark is off-center from the wheel surface, the welding carriage is moved along the width of the welding carriage by the drive component until the weld mark is located in the center of the wheel surface.

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