A towing method for installing rigid legs of large gantry crane

Abstract

The present application discloses a method for installing and towing a rigid leg of a large gantry crane, and relates to the field of manufacturing technology of a gantry of a gantry crane, and includes the following steps: a component installation step, in which a rotating upper hinge seat is installed at a position of the main beam near the first closing opening, and a rotating lower hinge seat is installed at a position of the inner side of the rigid leg near the second closing opening; a rigid leg connection step, in which the horizontally placed rigid leg is moved to the bottom of the main beam, the height position of the rigid leg is adjusted, and the rotating upper hinge seat and the rotating lower hinge seat are connected by connecting the eyeglass plate, and a tail hinge seat is provided at the tail of the rigid leg, and a tail rolling trolley is installed on the tail hinge seat of the rigid leg; a rigid leg erection step, in which the main beam is lifted as a whole, and the main beam drives the rigid leg to erect through a double hinge connection assembly, and the lifting assembly pulls the outer side of the rigid leg to straighten the rigid leg, and the rigid leg is supported. The present application can reduce the demand for the overall assembly site for overall lifting, and at the same time reduce the accuracy requirements for the hinge points connecting the main beam and the rigid leg.

Description

Technical Field

[0001] The present application relates to the technical field of portal crane gantry manufacturing, and in particular to a method for installing a towing strap on the rigid legs of a large gantry crane. Background Art

[0002] In the general assembly of a large gantry crane, the rigid legs need to be closed with the main beam. Specifically, a lifting tower is used to lift the main beam. During the process of lifting the main beam, the rigid legs are dragged, the horizontal rigid legs are erected, and then closed.

[0003] At present, the towing method for the rigid legs is external towing or side towing. The external towing method requires the rigid legs to be set on the outside of the main beam and then towed, and the side towing method requires the rigid legs to be set on the side of the main beam and then towed. These two methods require a larger assembly site, which increases the overall demand for assembly sites. In addition, whether it is external towing or side towing, the connection hinge between the main beam and the rigid legs requires high precision. If the precision is insufficient, it is easy to cause excessive rotation resistance of the connection hinge during the towing process, and the closing and docking precision between the main beam and the rigid legs is also difficult to guarantee. Summary of the invention

[0004] The present application aims to solve at least one of the above-mentioned technical problems in the prior art to a certain extent. To this end, the present application provides a method for installing a towing belt on a rigid leg of a large gantry crane, which can reduce the demand for the overall assembly site for overall lifting and reduce the accuracy requirements of the hinge point between the main beam and the rigid leg.

[0005] The method for installing a towing belt on a rigid leg of a large gantry crane according to an embodiment of the present application comprises the following steps:

[0006] Component installation step: the lower end surface of the main beam has a first closing opening for connecting the rigid leg, the head of the rigid leg has a second closing opening for connecting the main beam, a rotating upper hinge seat is installed at a position of the main beam close to the first closing opening, and a rotating lower hinge seat is installed at a position of the inner side surface of the rigid leg close to the second closing opening;

[0007] The rigid leg connecting step comprises adjusting the height of the main beam until the rigid leg can enter under the main beam, moving the horizontally placed rigid leg to under the main beam, adjusting the height position of the rigid leg, connecting the rotating upper hinge seat and the rotating lower hinge seat by connecting the eyeglass plate, one end of the connecting eyeglass plate is hinged to the rotating upper hinge seat, and the other end of the connecting eyeglass plate is hinged to the rotating lower hinge seat, the rotating upper hinge seat, the connecting eyeglass plate and the rotating lower hinge seat form a double hinge connection assembly, and the double hinge connection assembly is located on the inner side of the closing mouth of the main beam and the rigid leg, and the tail of the rigid leg is provided with a tail hinge seat, and the tail rolling trolley is installed on the tail hinge seat of the rigid leg, and the height of the rigid leg is lowered so that the tail rolling trolley falls on the bearing road base plate;

[0008] In the step of erecting the rigid legs, the main beam is lifted as a whole, and the main beam drives the rigid legs to be erected through the double-hinged connection assembly. The tail-sliding rolling trolley at the tail of the rigid legs rolls forward, and the lifting assembly pulls the outer side of the rigid legs to straighten the rigid legs, thereby completing the support of the rigid legs.

[0009] In an optional or preferred embodiment, the hinge point hole of the rotating upper hinge seat is an oblong hole, and the up and down movement stroke is 50 mm.

[0010] In an optional or preferred embodiment, the rotating upper hinge seat is installed on the left and right sides, the coaxiality of the hinge holes on both sides is ≤2mm, and the perpendicularity of the axes of the hinge holes on both sides to the center line of the main beam is ≤2mm.

[0011] In an optional or preferred embodiment, the rotating lower hinge seat is installed on the left and right sides, the coaxiality of the hinge holes on both sides is ≤2mm, and the axes of the hinge holes on both sides are perpendicular to the center line of the rigid leg by ≤2mm; the tail hinge seat is installed on the left and right sides, the coaxiality of the hinge holes on both sides is ≤2mm, and the axes of the hinge holes on both sides are perpendicular to the center line of the rigid leg by ≤2mm.

[0012] In an optional or preferred embodiment, the lifting assembly includes a winch, a fixed pulley block arranged on the outer side of the main beam, and a movable pulley block arranged on the outer side of the rigid leg, the winch has a steel wire rope for winding the fixed pulley block and the movable pulley block; in the rigid leg connecting step, the lifting assembly is installed; in the rigid leg erecting step, the winch cooperates to send out the steel wire rope during the rigid leg erection process.

[0013] In an optional or preferred embodiment, a straightened upper lifting lug is installed on the outer side of the main beam for connection with the fixed pulley block; a straightened lower lifting lug is installed on the outer side of the rigid leg near the second closing opening for connection with the movable pulley block.

[0014] In an optional or preferred embodiment, the installation steps of the lifting assembly include: first installing the straightened upper lifting ear on the main beam, and installing the straightened lower lifting ear on the rigid leg; then hanging the fixed pulley block on the straightened upper lifting ear through a first shackle, and hanging the movable pulley block on the straightened lower lifting ear through a second shackle; then anchoring the winch to the ground, installing a wire rope, and connecting the fixed pulley block, the movable pulley block, and the winch into a complete lifting assembly through the wire rope.

[0015] In an optional or preferred embodiment, in the step of raising the rigid legs, the main beam is lifted as a whole until the rigid legs are completely off the ground and the tail rolling trolley is about to leave the ground and then removed.

[0016] In an optional or preferred embodiment, after removing and starting the tail rolling trolley, the winch is started to tighten the wire rope, and under the traction of the fixed pulley block and the movable pulley block, the rigid leg is gradually straightened to complete the towing of the rigid leg.

[0017] In an optional or preferred embodiment, in the rigid leg connecting step, the rigid legs are carried by a self-propelled hydraulic flatbed vehicle, and the self-propelled hydraulic flatbed vehicle can adjust its own height.

[0018] Based on the above technical solution, the embodiment of the present application has at least the following beneficial effects: the above technical solution,

[0019] First, the present application adopts a method of towing the rigid legs under the main beam, which is to place the rigid legs horizontally under the main beam for towing, and connect the rigid legs to the main beam through a double hinge connection assembly. As the main beam is lifted, the rigid legs slowly stand up, and the tail-hinged rolling trolley gradually moves forward to the outside, and then the rigid legs are straightened by the lifting assembly on the outside. Compared with the external towing method of the rigid legs on the outside of the main beam or the side towing method on the side of the main beam, this method of internal towing under the main beam can reduce the overall lifting demand for the assembly site and improve safety.

[0020] Secondly, the double-hinge connection component connecting the main beam and the rigid leg adopts a double-hinge design. The rotating upper hinge seat and the rotating lower hinge seat are connected by connecting the eyeglass plate. Compared with the single-hinge connection method, the installation accuracy requirements of the rotating upper hinge seat and the rotating lower hinge seat can be reduced to prevent the problem of excessive hinge rotation resistance during towing due to insufficient installation accuracy; in addition, the hinge point hole of the rotating upper hinge seat is set as an oblong hole, and when the rigid leg is closed and docked with the main beam, the rigid leg can also be fine-tuned and then correspond to the reinforcement plate of the main beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present application is further described below with reference to the accompanying drawings and embodiments;

[0022] Figure 1 is a structural schematic diagram of the rigid leg connection step in an embodiment of the present application, wherein the lifting assembly has been installed;

[0023] Figure 2 yes Figure 1 Side view in the middle A direction;

[0024] Figure 3 yes Figure 1 A partial enlarged view of circle B in the middle;

[0025] Figure 4 yes Figure 1 A partial enlarged view of the middle C circle;

[0026] Figure 5 yes Figure 1 A partial enlarged view of circle D in the middle;

[0027] Figure 6 is a schematic structural diagram of the rigid leg connection step in an embodiment of the present application, wherein the lifting assembly is not installed;

[0028] Figure 7 yes Figure 6 A partial enlarged view of circle E in the middle;

[0029] Figure 8 is a structural schematic diagram of the rigid leg erecting step in an embodiment of the present application;

[0030] Fig. 9 Yes Yes Figure 8 A partial enlarged view of circle F in the middle.

[0031] Reference numerals: main beam 11, first closing opening 12;

[0032] Rigid legs 21, second closing opening 22;

[0033] Lifting tower 31;

[0034] The double hinge connection assembly 40 rotates the upper hinge seat 41, rotates the lower hinge seat 42, and connects the eyeglass plate 43;

[0035] Lifting assembly 50, straightening upper lifting lug 51, first shackle 52, fixed pulley block 53, straightening lower lifting lug 54, second shackle 55, movable pulley block 56, winch 57, wire rope 58;

[0036] Tail hinge seat 61, tail rolling trolley 62;

[0037] Self-propelled hydraulic flatbed truck 71. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0041] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0044] Reference Figure 1 The lower end surface of the main beam 11 has a first closing opening 12 for connecting the rigid leg 21, and the head of the rigid leg 21 has a second closing opening 22 for connecting the main beam 11. In the assembly of a large gantry crane, the rigid leg 21 needs to be closed with the main beam 11, that is, the first closing opening 12 is aligned with the second closing opening 22.

[0045] At present, the existing technology is to use a lifting tower to lift the main beam. In the process of lifting the main beam, the rigid legs are towed, the horizontal rigid legs are erected, and then closed. The towing method of the rigid legs is an external towing method or a side towing method. The external towing method requires the rigid legs to be set on the outside of the main beam and then towed, and the side towing method requires the rigid legs to be set on the side of the main beam and then towed. These two methods require a larger assembly site, which increases the overall lifting demand for the assembly site.

[0046] Refer to the following Figures 1 to 9 This embodiment describes a method for installing a towing belt on a rigid leg of a large gantry crane, which specifically includes the following steps:

[0047] Component installation steps:

[0048] Reference Figures 1 to 5 A rotating upper hinge seat 41 is installed at a position of the main beam 11 near the first closing opening 12, and the bearing capacity of the rotating upper hinge seat 41 meets the requirements. The rotating upper hinge seat 41 is installed on the left and right sides, and the coaxiality of the hinge holes on both sides is ≤2mm, and the verticality of the axes of the hinge holes on both sides to the center line of the main beam 11 is ≤2mm.

[0049] A swivel lower hinge seat 42 is installed on the inner side of the rigid leg 21 near the second closing opening, and the bearing capacity of the swivel lower hinge seat 41 meets the requirements. The swivel lower hinge seat 42 is installed on the left and right sides, and the coaxiality of the hinge holes on both sides is ≤2mm, and the axes of the hinge holes on both sides are perpendicular to the center line of the rigid leg 21 by ≤2mm.

[0050] A tail hinge seat 61 is installed at the tail of the rigid leg 21, and the bearing capacity of the tail hinge seat 61 meets the requirements. The tail hinge seat 61 is installed on the left and right sides, and the coaxiality of the hinge holes on both sides is ≤2mm, and the axes of the hinge holes on both sides are perpendicular to the center line of the rigid leg 21 by ≤2mm.

[0051] A straightened upper lifting lug 51 is installed on the outer side of the main beam 11, and a straightened lower lifting lug 54 is installed on the outer side of the rigid leg 21 near the second closing opening. The bearing capacities of the straightened upper lifting lug 51 and the straightened lower lifting lug 54 both meet the requirements.

[0052] It should be noted that the inner side and outer side of the rigid leg 21 are based on the erected state. Figure 8 shown.

[0053] Rigid Leg Connection Steps:

[0054] Reference Figure 6 to Figure 7 , adjust the height of the main beam 11 until the rigid legs 21 can enter the bottom of the main beam 11, and move the horizontally placed rigid legs 21 to the bottom of the main beam 11. In this embodiment, the height of the main beam 11 is raised by two lifting towers 31, which is a prior art and will not be described in detail; in addition, Figure 6 The rigid leg 21 is carried by a self-propelled hydraulic flatbed truck 71, and the self-propelled hydraulic flatbed truck 71 can adjust its own height. It can be understood that in this embodiment, the rigid leg 21 can be moved by being carried by two groups of self-propelled hydraulic flatbed trucks 71, and can also be raised and lowered within a certain height.

[0055] After the horizontal position of the rigid leg 21 is moved, the height position of the rigid leg 21 is adjusted, and the rotating upper hinge seat 41 and the rotating lower hinge seat 42 are connected by connecting the eyeglass plate 43. One end of the connecting eyeglass plate 43 is hinged to the rotating upper hinge seat 41, and the other end of the connecting eyeglass plate 43 is hinged to the rotating lower hinge seat 42. The rotating upper hinge seat 41, the connecting eyeglass plate 43 and the rotating lower hinge seat 42 form a double hinge connection assembly 40, which is located on the inner side of the closing opening between the main beam 11 and the rigid leg 21. Figure 6 and Figure 7 A tail hinge seat 61 is provided at the tail of the rigid leg 21, and a tail rolling trolley 62 is installed on the tail hinge seat 61 of the rigid leg 21. The height of the rigid leg 21 is lowered by a self-propelled hydraulic flatbed vehicle 71 so that the tail rolling trolley 62 falls on the bearing road substrate.

[0056] Install the lifting assembly 50. In this embodiment, the lifting assembly 50 includes a winch 57, a fixed pulley block 53 arranged on the outer side of the main beam 11, and a movable pulley block 56 arranged on the outer side of the rigid leg 21. The winch 57 has a wire rope 58 for winding the fixed pulley block 53 and the movable pulley block 56. The specific installation steps of the lifting assembly 50 are to install the straightening upper lifting lug 51 and the straightening upper lifting lug 51 according to the above-mentioned component installation steps. In the rigid leg connection step, the fixed pulley block 53 is hung on the straightening upper lifting lug 51 through the first shackle 52, and the movable pulley block 56 is hung on the straightening lower lifting lug 54 through the second shackle 55; then the winch 57 is anchored and fixed on the ground, and the anchoring force meets the requirements, and the wire rope 58 is installed. The fixed pulley block 53, the movable pulley block 56, and the winch 57 are connected to form a complete lifting assembly through the wire rope 58, and the bearing capacity of the wire rope meets the requirements. Among them, the bearing capacity of the first shackle 52 and the second shackle 55 both meet the requirements, and the present embodiment adopts an 85t shackle; the bearing capacity of the fixed pulley block 53 and the movable pulley block 56 both meet the requirements, and the present embodiment adopts a 100t pulley block; the specific winding method of the wire rope 58 can be set with reference to the existing one, which will not be elaborated here.

[0057] Rigid Leg Raise Steps:

[0058] The main beam 11 is lifted up slowly as a whole through the lifting tower 31, and the main beam 11 drives the rigid leg 21 to slowly stand up through the double hinge connection assembly 40, and the tail rolling trolley 62 at the tail of the rigid leg 21 rolls forward. During the erection process of the rigid leg 21, the winch 57 cooperates to send out the wire rope 58. The main beam 11 is lifted up as a whole until the rigid leg 21 is completely out of the air, and the tail rolling trolley 62 is about to leave the ground and fly into the air, at which time the tail rolling trolley 62 is removed.

[0059] After the main dismantling starts the tail rolling trolley 62, the winch 57 is started to tighten the wire rope 58, and under the traction of the fixed pulley block 53 and the movable pulley block 56, the rigid leg 21 is gradually straightened to complete the towing of the rigid leg 21.

[0060] It is understandable that the rigid leg has a large weight, large size, high precision requirements, and its installation quality is related to the safety, reliability and usability of the whole machine. This application ensures that the installation of the rigid leg meets the design and use requirements through a reasonable rigid leg installation and towing method. This application adopts a towing installation method of the rigid leg 21 under the main beam 11, which is to place the rigid leg 21 horizontally under the main beam 11 for towing, and connect the rigid leg 21 to the main beam 11 through a double hinge connection assembly 40. As the main beam 11 is lifted, the rigid leg 21 slowly stands up, and the tail-hinged rolling trolley 62 gradually moves forward to the outside, and then the rigid leg is straightened by the lifting assembly on the outside. Compared with the external towing method of the rigid leg on the outside of the main beam or the side towing method on the side of the main beam, this method of internal towing under the main beam can reduce the overall lifting demand for the assembly site and improve safety.

[0061] Among them, the double-hinge connection component connecting the main beam 11 and the rigid leg 21 adopts a double-hinge design. The rotating upper hinge seat 41 and the rotating lower hinge seat 42 are connected by connecting the eyeglass plate 43. Compared with the single-hinge connection method, the installation accuracy requirements of the rotating upper hinge seat 41 and the rotating lower hinge seat 42 can be reduced to prevent the problem of excessive hinge rotation resistance during towing due to insufficient installation accuracy; in addition, the hinge point hole of the rotating upper hinge seat 41 is set as an oblong hole with an up and down movement stroke of 50mm. When the rigid leg 21 is closed and docked with the main beam 11, the rigid leg 21 can also be fine-tuned and then correspond to the reinforcement plate of the main beam.

[0062] The present application discloses a method for installing and towing the rigid legs of a large gantry crane. By formulating a reasonable and feasible method for installing and towing the rigid legs of a large gantry crane, it ensures that the rigid legs are safely and reliably erected when the whole machine is installed, and are closed and docked with the end beam part of the main beam. The installation accuracy meets the requirements, and the rigid leg towing installation has small requirements for the overall assembly site and is economical and reliable, thereby ensuring the safety and reliability of the whole machine.

[0063] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A method for installing a towing belt on a rigid leg of a large gantry crane, characterized in that: The following steps are involved: Component installation step: the lower end surface of the main beam has a first closing opening for connecting the rigid leg, the head of the rigid leg has a second closing opening for connecting the main beam, a rotating upper hinge seat is installed at a position of the main beam close to the first closing opening, and a rotating lower hinge seat is installed at a position of the inner side surface of the rigid leg close to the second closing opening; The rigid leg connecting step comprises adjusting the height of the main beam until the rigid leg can enter under the main beam, moving the horizontally placed rigid leg to under the main beam, adjusting the height position of the rigid leg, connecting the rotating upper hinge seat and the rotating lower hinge seat by connecting the eyeglass plate, one end of the connecting eyeglass plate is hinged to the rotating upper hinge seat, and the other end of the connecting eyeglass plate is hinged to the rotating lower hinge seat, the rotating upper hinge seat, the connecting eyeglass plate and the rotating lower hinge seat form a double hinge connection assembly, and the double hinge connection assembly is located on the inner side of the closing mouth of the main beam and the rigid leg, and the tail of the rigid leg is provided with a tail hinge seat, and the tail rolling trolley is installed on the tail hinge seat of the rigid leg, and the height of the rigid leg is lowered so that the tail rolling trolley falls on the bearing road base plate; In the step of erecting the rigid legs, the main beam is lifted as a whole, and the main beam drives the rigid legs to be erected through the double-hinged connection assembly. The tail-sliding rolling trolley at the tail of the rigid legs rolls forward, and the lifting assembly pulls the outer side of the rigid legs to straighten the rigid legs, thereby completing the support of the rigid legs.

2. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 1, characterized in that: The hinge point hole of the rotating upper hinge seat is an oblong hole, and the up and down movement stroke is 50mm.

3. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 2 is characterized in that: The rotating upper hinge seat is installed on the left and right sides, the coaxiality of the hinge holes on both sides is ≤2mm, and the verticality of the axes of the hinge holes on both sides and the center line of the main beam is ≤2mm.

4. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 1, characterized in that: The rotating lower hinge seat is installed on the left and right sides, the coaxiality of the hinge holes on both sides is ≤2mm, and the axes of the hinge holes on both sides are perpendicular to the center line of the rigid leg by ≤2mm; the tail hinge seat is installed on the left and right sides, the coaxiality of the hinge holes on both sides is ≤2mm, and the axes of the hinge holes on both sides are perpendicular to the center line of the rigid leg by ≤2mm.

5. The method for installing a towing belt on a rigid leg of a large gantry crane according to any one of claims 1 to 4, characterized in that: The lifting assembly includes a winch, a fixed pulley block arranged on the outer side of the main beam, and a movable pulley block arranged on the outer side of the rigid leg. The winch has a steel wire rope for winding the fixed pulley block and the movable pulley block. In the rigid leg connection step, the lifting assembly is installed. In the rigid leg erection step, the winch cooperates to send out the steel wire rope during the rigid leg erection process.

6. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 5, characterized in that: A straightened upper lifting lug is installed on the outer side of the main beam for connection with the fixed pulley block; a straightened lower lifting lug is installed on the outer side of the rigid leg near the second closing opening for connection with the movable pulley block.

7. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 6, characterized in that: The installation steps of the lifting assembly include: first installing the straightened upper lifting ear on the main beam, and installing the straightened lower lifting ear on the rigid leg; then hanging the fixed pulley block on the straightened upper lifting ear through a first shackle, and hanging the movable pulley block on the straightened lower lifting ear through a second shackle; then anchoring the winch on the ground, installing a wire rope, and connecting the fixed pulley block, the movable pulley block, and the winch into a complete lifting assembly through the wire rope.

8. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 7, characterized in that: In the rigid leg erecting step, the main beam is lifted as a whole until the rigid legs are completely out of the air, and the tail rolling trolley is about to leave the ground and fly into the air, at which time the tail rolling trolley is removed.

9. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 8, characterized in that: After the tail rolling trolley is dismantled and started, the winch is started to tighten the wire rope, and under the traction of the fixed pulley block and the movable pulley block, the rigid leg is gradually straightened to complete the towing of the rigid leg.

10. The method for installing a towing belt on a rigid leg of a large gantry crane according to claim 1, characterized in that: In the rigid leg connection step, the rigid leg is carried by a self-propelled hydraulic flatbed truck, which can adjust its own height.

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