Large floating crane sub-arm mounting structure and mounting method

Abstract

The application discloses a large floating crane auxiliary arm mounting structure and mounting method, and relates to the technical field of floating crane auxiliary arm mounting, which comprises two groups of hinged components for hingedly suspending the auxiliary arm on a main box body, each group comprising a hinged seat, a hinged rod and a double-hole hinged piece; the hinged seat is fixed on the top of the main box body and rotationally connected with one end of the hinged rod, the other end of the hinged rod is rotationally connected with one hole of the double-hole hinged piece, and the other hole of the double-hole hinged piece is sleeved on a truss chord of the auxiliary arm; two groups of supporting brackets correspond to the hinged components one by one and are used for supporting the auxiliary arm, each group comprising an upper bracket and a lower bracket; the upper bracket is fixed on the auxiliary arm, the lower bracket is fixed on the main box body, and the upper bracket is supported by the lower bracket. After the auxiliary arm is hoisted and positioned, only two steps of operation of lowering the upper bracket to the lower bracket and penetrating the hinged rod are needed to form a stable temporary fixed state, and then the floating crane can be removed, thereby getting rid of the long-time dependence on large lifting equipment in the traditional process.

Description

Technical Field

[0001] This invention relates to the field of floating crane jib installation technology, specifically to a large floating crane jib installation structure and installation method. Background Technology

[0002] Floating cranes (floating hoists) are core equipment for heavy-duty lifting at sea and are widely used in offshore wind power installation, large ship construction, and offshore platform construction. Their boom system consists of a main boom, a main housing, and an auxiliary boom. The main housing is the box-shaped main load-bearing section of the main boom, and the root end of the auxiliary boom is fixed to the end of the main housing, thus forming an integrated boom structure extending from the main housing to the auxiliary boom. The main function of the auxiliary boom is to significantly increase the crane's operating radius and adjust the hook's luffing angle to meet the heavy-duty lifting needs far from the ship's hull.

[0003] Compared to common land-based mobile cranes, offshore floating crane jibs differ significantly in function and installation: Ordinary land-based crane jibs only assist the main boom in lifting, have simple loads, operate in a stable environment, and have lower requirements for dynamic stability; offshore floating crane jibs operate in deep-sea environments, needing to withstand enormous static loads and resist dynamic alternating loads, requiring structural safety and fatigue life far exceeding those of conventional crane jibs. Regarding installation, ordinary land-based crane jibs can be assembled at a low position on the ground, relying on their own equipment for flipping and docking, with less dependence on external large lifting equipment and easier alignment and welding; large offshore floating crane jibs are large and heavy, with the jib hook significantly off the ground during boom manufacturing, requiring the jib structure to be installed on-site, necessitating prolonged installation and welding assistance from a large floating crane.

[0004] Due to the unique characteristics of the floating crane's jib, traditional on-site installation methods often employ direct butt welding. Specifically, after the main hull is hoisted into place, a large floating crane is used to suspend the heavy jib for an extended period, barely allowing its end face to align with the main hull's end face. Welders then perform circumferential welding at high altitude. This process has significant drawbacks: firstly, the equipment cost of large floating cranes is extremely high, and the prolonged waiting time for welding completion results in a huge waste of resources; secondly, in the high-altitude suspended state, the jib is highly unstable due to wind force and rope swaying, leading to significant misalignment, difficulty in guaranteeing welding quality, and serious safety hazards. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a large floating crane jib installation structure and installation method. After the jib is hoisted into place, only two steps are required to lower it to the upper bracket and place it on the lower bracket and insert the hinge rod to form a stable temporary fixed state. The floating crane can then be removed, eliminating the long-term dependence on large lifting equipment in traditional processes.

[0006] The technical solution of the present invention is as follows: In a first aspect of the present invention, a large floating crane auxiliary boom mounting structure is provided, comprising: A hinge assembly is used to hinge and suspend the auxiliary boom on the main body; the hinge assembly is provided in two sets, each set of hinge assembly includes a hinge seat, a hinge rod and a double-hole hinge member, the hinge seat is fixedly installed on the top of the main body, the hinge seat is rotatably connected to one end of the hinge rod, the other end of the hinge rod is rotatably connected to one hole of the double-hole hinge member, and the other hole of the double-hole hinge member is sleeved on the truss chord of the auxiliary boom; Support brackets are used to support the auxiliary boom; two sets of support brackets are provided, and the two sets of support brackets are correspondingly set with two sets of hinge components; each set of support brackets includes an upper bracket and a lower bracket, the upper bracket is fixed on the auxiliary boom, the lower bracket is fixed on the main body, and the lower bracket supports the upper bracket.

[0007] In some embodiments of the present invention, mounting holes are provided at both ends of the hinge rod, and the hinge seat includes two parallel and spaced ear plates with corresponding coaxial through holes. The pin at the end of the hinge rod passes through the through holes of the two ear plates to form a clamp-type hinge structure.

[0008] In some embodiments of the present invention, the double-hole hinge includes two parallel double-hole hinge plates spaced apart, and the hinge rod is located between the two double-hole hinge plates.

[0009] In some embodiments of the present invention, each double-hole hinge plate is provided with a first connecting hole and a second connecting hole. The first connecting holes on the two double-hole hinge plates are coaxially corresponding. The hinge rod is rotatably connected to the double-hole hinge plate by a pin. The second connecting holes on the two double-hole hinge plates are coaxially corresponding and are jointly sleeved on the truss chord of the auxiliary arm.

[0010] In some embodiments of the present invention, the upper bracket and the lower bracket have the same structure, each including two vertical plates and one horizontal plate; wherein, the horizontal plate of the upper bracket is fixedly connected to the lower end of the two vertical plates, and the horizontal plate of the lower bracket is fixedly connected to the upper end of the two vertical plates.

[0011] In some embodiments of the present invention, the two vertical plates of the upper bracket and the two vertical plates of the lower bracket are both right-angled trapezoidal plates; one right-angled side of the right-angled trapezoidal plate is fixedly connected to the horizontal plate, and the other right-angled side is fixedly connected to the main box or the auxiliary arm.

[0012] In some embodiments of the present invention, the upper bracket is fixed on the side of the docking end face of the auxiliary arm, and the lower bracket is fixed on the docking end face of the main body. In the installation and support state, the horizontal plate of the upper bracket and the horizontal plate of the lower bracket are face to face and fit together, and the two vertical plates of the upper bracket and the two vertical plates of the lower bracket are perpendicular to each other, that is, the upper bracket and the lower bracket are arranged at a 90° intersection.

[0013] In a second aspect of the present invention, a method for installing a large floating crane jib is provided, comprising the following steps: S1. During boom production, the articulated base and lower bracket are pre-installed in the corresponding positions of the main body; at the same time, the double-hole articulated component and upper bracket are pre-installed in the corresponding positions of the auxiliary boom. S2. When installing the auxiliary boom, use a floating crane to lift the auxiliary boom to the vicinity of the docking end face of the main body, and lower the auxiliary boom so that the upper bracket rests on the lower bracket to form a pressure support; S3. Then, the two ends of the hinge rod are rotatably connected to the hinge seat and the double-hole hinge piece respectively, so that the auxiliary arm and the main box form a temporary fixed state of upper hinge and lower support. S4. After confirming that the auxiliary boom is in a stable position, remove the floating crane equipment, weld the circumferential seam between the auxiliary boom and the main body to connect them into one unit, and complete the installation of the auxiliary boom.

[0014] In some embodiments of the present invention, before removing the floating crane, the gap between the auxiliary boom and the main body is finely adjusted by utilizing the rotational connection between the auxiliary boom and the main body through the hinge assembly. After confirming that the gap meets the welding process requirements, the floating crane is then removed.

[0015] In some embodiments of the present invention, after welding is completed, the hinge assembly and the support bracket are not removed and are retained as permanent auxiliary support structures.

[0016] One or more technical solutions of the present invention have the following beneficial effects: (1) This invention establishes an "upper hinge, lower support" installation support system by setting up two sets of hinge components and two sets of support brackets. The hinge components suspend the auxiliary boom on the main body, providing horizontal constraints and rotational freedom; the support brackets support and share the weight of the auxiliary boom through the surface contact between the upper and lower brackets. This system allows the auxiliary boom to be lowered into place after hoisting, and the upper bracket to be placed on the lower bracket and the hinge rod to be inserted, forming a stable temporary fixed state. The floating crane can then be removed, completely eliminating the long-term dependence on large lifting equipment in traditional processes. At the same time, the butt joint circumferential welding is carried out in the absence of load interference after the floating crane is removed, effectively avoiding misalignment caused by wind vibration during high-altitude suspension and rope swing, greatly improving welding quality and construction safety.

[0017] (2) This invention constructs a flexible spatial linkage hinge chain by using a double-ear plate clamping hinge seat, a double-hole hinge plate clamping the hinge rod, and a first and second connection hole with separate functions on the two plates. This allows the auxiliary arm to swing slightly around the hinge axis to achieve on-site fine adjustment of the docking gap, significantly reducing the high-altitude alignment accuracy requirements. At the same time, both the upper and lower brackets adopt a structure of two vertical plates plus one horizontal plate. The vertical plates are right-angled trapezoidal plates with two right-angled sides connecting the horizontal plate and the side, respectively. This allows the two to lock a 90° intersecting spatial posture during the factory prefabrication stage. On-site, the upper bracket horizontal plate only needs to be placed face down on the lower bracket horizontal plate for automatic and accurate positioning without manual angle adjustment. In addition, the bracket is fixed to the side of the docking end face of the auxiliary arm without protruding from the end face, and does not interfere with the welding operation of the docking circumferential seam at all, realizing efficient collaboration throughout the entire process from pre-assembly, hoisting, fine adjustment, support to welding.

[0018] (3) The installation method provided by this invention pre-fixes the hinge seat and lower bracket to the main body, and pre-fixes the double-hole hinge and upper bracket to the auxiliary boom, minimizing the workload on site. Before removing the floating crane, the rotational freedom provided by the hinge is used to finely adjust the butt joint gap with zero risk, and the welding is carried out after confirming that the welding process requirements are met. More importantly, after welding, the hinge assembly and support bracket are not removed, but are retained at the boom node as a permanent auxiliary support structure. Under normal service conditions, this structure does not affect the stress of the main weld. When the butt weld cracks locally due to fatigue cracks or overload, the retained hinge assembly and support bracket can immediately provide a secondary load-bearing path to prevent the auxiliary boom from falling off suddenly, fundamentally solving the problem of fall prevention safety of key nodes of large floating crane booms under extreme conditions. Attached Figure Description

[0019] Figure 1 This is a front view of the large floating crane auxiliary boom after installation according to the present invention; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a top view of the large floating crane auxiliary boom after installation according to the present invention; Figure 4 for Figure 3 A magnified view of a section at point B in the middle; Figure 5 This is a schematic diagram of the hinge assembly of the present invention; Figure 6 This is a schematic diagram of the support bracket of the present invention.

[0020] In the diagram: 1. Main boom; 2. Main housing; 3. Secondary boom; 301. Truss chord; 4. Hinge assembly; 401. Hinge seat; 402. Hinge rod; 403. Double-hole hinge; 404. First connecting hole; 405. Second connecting hole; 5. Support bracket; 501. Upper bracket; 502. Lower bracket; 503. Vertical plate; 504. Horizontal plate. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] Example 1 In a typical embodiment of the present invention, a large floating crane auxiliary boom installation structure is proposed, such as... Figures 1 to 6 As shown, it includes two sets of hinge components 4 and two sets of support brackets 5. The hinge components 4 and support brackets 5 are set one-to-one. The hinge components 4 are used to hinge and suspend the auxiliary arm 3 on the main housing 2 to achieve temporary fixation and posture adjustment of the auxiliary arm 3 during the installation process. The support brackets 5 are used to support the auxiliary arm 3 to share the weight of the auxiliary arm 3 and provide stable bottom support. The hinge components 4 and support brackets 5 together constitute an "upper hinge and lower support" installation support system.

[0024] Specifically, such as Figure 5As shown, the hinge assembly 4 includes a hinge seat 401, a hinge rod 402, and a double-hole hinge 403. The hinge seat 401 is fixedly installed on the top of the main housing 2. The hinge seat 401 is rotatably connected to one end of the hinge rod 402, and the other end of the hinge rod 402 is also rotatably connected to one of the holes of the double-hole hinge 403. The other hole of the double-hole hinge 403 is fitted onto the truss chord 301 of the secondary arm 3. The hinge seat 401 and one end of the hinge rod 402 form a first revolute joint, and the other end of the hinge rod 402 and the first hole of the double-hole hinge 403 form a second revolute joint. The second hole of the double-hole hinge 403 is fitted onto the chord 301 of the truss of the secondary arm 3, thus forming a spatial linkage chain. The secondary arm 3 can pitch and swing within a certain angle range around the hinge axis. The hinge assembly 4 provides horizontal constraints and rotational freedom (allowing fine adjustments), enabling the secondary arm 3 to adjust its posture during installation to meet subsequent welding requirements. In addition, the two sets of hinge components 4 are arranged symmetrically along the boom to avoid torsion problems caused by unilateral force.

[0025] The specific structure of the support bracket 5 is as follows: Figure 6 As shown, the support bracket 5 mainly consists of two parts: an upper bracket 501 and a lower bracket 502. The upper bracket 501 is pre-welded or fastened to a designated position on the auxiliary boom 3 before hoisting, while the lower bracket 502 is also pre-fixed to the main housing 2. During installation, when the auxiliary boom 3 is lowered, the lower bracket 502 directly supports the upper bracket 501, forming a reliable pressure-bearing contact surface.

[0026] In this embodiment, mounting holes are provided at both ends of the hinge rod 402, and the hinge seat 401 includes two parallel and spaced ear plates with corresponding coaxial through holes. The pin at the end of the hinge rod 402 passes through the through holes of the two ear plates, forming a clamp-type hinge structure. The double ear plates clamp the hinge rod 402, and the load is evenly distributed by the two ear plates, reducing the force on a single plate by half. This significantly improves the load-bearing capacity and fatigue life of the joint. The pin can be inserted laterally (from the outside of the boom to the inside), providing a large operating space and eliminating the need for special tools during high-altitude operations.

[0027] Furthermore, the double-hole hinge 403 includes two parallel double-hole hinge plates spaced apart, and the hinge rod 402 is located between the two double-hole hinge plates. The double-plate structure enhances the bending and torsional stiffness of the connection. Both ends of the hinge rod 402 adopt a "double-plate clamping single rod" form, with consistent force distribution and more uniform bending moment distribution inside the rod. The two hinge plates clamp the truss chord 301 from both sides, so that when one plate fails, the other plate can still maintain basic constraint, improving safety.

[0028] Furthermore, each double-hole hinge piece is provided with a first connecting hole 404 and a second connecting hole 405. The first connecting holes 404 on the two double-hole hinge pieces are coaxially corresponding. The hinge rod 402 is rotatably connected to the double-hole hinge piece by a pin to realize the hinge function. The second connecting holes 405 on the two double-hole hinge pieces are coaxially corresponding and are jointly sleeved on the truss chord 301 of the secondary arm 3. The first connecting hole 404 is responsible for hinge rotation, and the second connecting hole 405 is responsible for connection with the truss chord 301. They are independently stressed and will not affect the function of the other part due to deformation of one part. The second connecting holes 405 on the two double-hole hinge pieces are coaxially sleeved on the truss chord 301, which is firmly connected and does not damage the truss chord 301 body. The inner diameter of the second connecting hole 405 is slightly larger than the outer diameter of the chord, allowing a certain gap, which is convenient for quick on-site insertion. Through the above structure, a firm connection between the double-hole hinge piece 403 and the secondary arm 3 is realized.

[0029] In this embodiment, the upper bracket 501 and the lower bracket 502 have the same structure, each including two vertical plates 503 and one horizontal plate 504. The horizontal plate 504 of the upper bracket 501 is fixedly connected to the lower end of the two vertical plates 503 to support the auxiliary arm 3. The horizontal plate 504 of the lower bracket 502 is fixedly connected to the upper end of the two vertical plates 503 to provide an upward support surface. The three steel plates can be welded together without casting or complex machining. The two vertical plates 503 form a "wall-like" bending section, which is less prone to bending deformation or instability when bearing vertical loads of hundreds of tons for the auxiliary arm 3. Furthermore, the identical structure of the upper bracket 501 and the lower bracket 502 allows for batch cutting and standardized processing in the factory, reducing the variety of parts.

[0030] Furthermore, both vertical plates 503 of the upper bracket 501 and both vertical plates 503 of the lower bracket 502 are right-angled trapezoidal plates; one right-angled side of the right-angled trapezoidal plate is fixedly connected to the horizontal plate 504, and the other right-angled side is fixedly connected to the main box 2 or the auxiliary arm 3. This trapezoidal structure is beneficial for optimizing stress distribution and enhancing the stability of the structure.

[0031] Since the width of the main housing 2 is greater than the width of the end face of the auxiliary arm 3, the upper bracket 501 is fixed on the side of the docking end face of the auxiliary arm 3, and the lower bracket 502 is fixed on the docking end face of the main housing 2. In the installation and support state, the horizontal plate 504 of the upper bracket 501 and the horizontal plate 504 of the lower bracket 502 are in face-to-face contact, forming a stable pressure contact. The two vertical plates 503 of the upper bracket 501 and the two vertical plates 503 of the lower bracket 502 are perpendicular to each other, that is, the upper bracket 501 and the lower bracket 502 are arranged at a 90° angle. The bracket is fixed to the side of the end face of the auxiliary boom 3, and the joint area is fully exposed, allowing welders to weld without obstruction. There is no need to remove the bracket during welding. The vertical plate 503 of the upper bracket 501 is parallel to the direction of the auxiliary boom 3, and the vertical plate 503 of the lower bracket 502 is parallel to the direction of the main box 2. The two cross each other to form a cross-shaped pressure-bearing node, which can not only bear pressure, but also restrict horizontal sliding. The angle is locked in the factory prefabrication stage. On site, only one "drop" action is needed to complete the precise positioning, which greatly shortens the hook-up time of the floating crane.

[0032] In the specific implementation of this invention, the hinge assembly 4 and the support bracket 5 are not simple positioning fixtures, but rather a force-bearing system specifically designed and verified according to the standards of temporary support structures during the steel structure construction stage. Taking a large floating crane with a total boom weight of approximately 2000 tons and an auxiliary boom 3 weight of approximately 300 tons as an example, its force transmission mechanism is as follows: the support bracket 5, as the main vertical bearing component, bears most of the vertical load generated by the self-weight of the auxiliary boom 3, forming a stable bottom support; the hinge assembly 4 mainly provides horizontal constraints and rotational freedom around the hinge axis, and shares the vertical component of the self-weight of the auxiliary boom 3 along the boom axis, preventing the auxiliary boom 3 from shifting or overturning at the moment of lifting. In the specific design, the bending stress, shear stress, and bearing stress of the pin and ear plate are verified according to the "Crane Design Code" (GB / T 3811), and the strength, stability, and stiffness of the right-angled trapezoidal plate of the bracket are verified according to the "Steel Structure Engineering Construction Code" (GB 50755). The importance coefficient of the temporary support structure shall be no less than 1.0, and the dynamic coefficient under hoisting conditions shall be 1.1 to 1.4. The pin shall be made of 40Cr alloy steel, with a diameter determined by stress calculation and no less than 100mm. The right-angled trapezoidal plate of the bracket shall be made of Q345 or Q460 grade steel plate with a thickness of no less than 30mm, and the weld shall be designed for full penetration welding to withstand the corresponding construction load. During installation, it is necessary to ensure that the center of gravity projection of the auxiliary boom 3 falls within the support envelope of the two sets of support brackets 5. The floating crane can only be slowly unloaded and removed after the hinge rod 402 is installed and the bracket horizontal plate 504 is confirmed to be fully attached to the support. Through the above-mentioned targeted structural design and stress calculation, the "upper hinge and lower support" system of the present invention can provide stable and reliable temporary support for the 300-ton auxiliary boom 3 after the removal of the floating crane and before the completion of welding; at the same time, after the welding is completed, each component remains in its original position, further forming a permanent auxiliary support structure, providing a secondary load-bearing path when the weld cracks locally due to fatigue or overload, and preventing the auxiliary boom 3 from suddenly falling off.

[0033] Example 2 In some embodiments of the present invention, a method for installing a large floating crane jib is provided, comprising the following steps: S1. Pre-installation is carried out during the boom production stage. The articulated base and lower bracket are pre-welded or bolted to the corresponding positions on the main body. At the same time, the double-hole articulated parts and upper bracket are pre-welded or bolted to the corresponding positions on the auxiliary boom, preparing for efficient on-site installation.

[0034] S2. At the installation site, use a floating crane to lift the auxiliary boom to the vicinity of the main body docking end face, and slowly lower the auxiliary boom so that the upper bracket on the auxiliary boom is accurately placed on the lower bracket of the main body, forming a preliminary pressure support. At this time, most of the weight of the auxiliary boom is borne by the support bracket.

[0035] S3. Then, the two ends of the hinge rod are respectively connected to the pre-installed hinge seat and the double-hole hinge piece by the pin shaft, so that the auxiliary arm and the main box form a temporary fixed state with the upper end hinged and the lower end supported. The auxiliary arm can be rotated and adjusted slightly around the hinge point.

[0036] S4. After confirming that the auxiliary boom is stable and the docking position is accurate, remove the floating crane equipment, and then weld the docking circumferential seam between the auxiliary boom and the main body to connect the two into one, thus completing the final installation of the auxiliary boom.

[0037] In this embodiment, before removing the floating crane, the circumferential gap between the auxiliary boom and the main body is fine-tuned using the rotational connection formed by the auxiliary boom and the main body via the hinge assembly. Once the gap is confirmed to meet welding requirements, the floating crane is removed. Before welding, the support bracket already bears the weight, but the hinge point still allows for slight rotation, eliminating the need for repeated lifting and lowering of the floating crane to correct the gap. During fine-tuning, the floating crane hook is still attached; if any abnormality is found during adjustment, it can be immediately restarted, ensuring zero-risk operation. Optimizing the gap before removal avoids the extreme situation of substandard welding quality and rework due to the inability to adjust after removal.

[0038] In this embodiment, after welding is completed, the hinge assembly and support bracket are not removed and are retained as permanent auxiliary support structures. Under normal working conditions, the butt weld is the main load-bearing component. When the weld cracks locally due to fatigue cracks, overload, or accidental damage, the retained hinge assembly and support bracket can immediately take over the load, prevent the jib from falling suddenly, and buy time for maintenance.

[0039] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A large floating crane auxiliary boom installation structure, characterized in that, include: A hinge assembly is used to hinge and suspend the auxiliary boom on the main body; the hinge assembly is provided in two sets, each set of hinge assembly includes a hinge seat, a hinge rod and a double-hole hinge member, the hinge seat is fixedly installed on the top of the main body, the hinge seat is rotatably connected to one end of the hinge rod, the other end of the hinge rod is rotatably connected to one hole of the double-hole hinge member, and the other hole of the double-hole hinge member is sleeved on the truss chord of the auxiliary boom; Support brackets are used to support the auxiliary boom; two sets of support brackets are provided, and the two sets of support brackets are correspondingly set with two sets of hinge components; each set of support brackets includes an upper bracket and a lower bracket, the upper bracket is fixed on the auxiliary boom, the lower bracket is fixed on the main body, and the lower bracket supports the upper bracket.

2. The large floating crane auxiliary boom installation structure as described in claim 1, characterized in that, Both ends of the hinge rod are provided with mounting holes. The hinge base includes two parallel and spaced ear plates, and coaxial through holes are opened on the two ear plates respectively. The pin at the end of the hinge rod passes through the through holes of the two ear plates to form a clamp-type hinge structure.

3. The large floating crane auxiliary boom installation structure as described in claim 1, characterized in that, The double-hole hinge includes two parallel double-hole hinge plates spaced apart, and the hinge rod is located between the two double-hole hinge plates.

4. The large floating crane auxiliary boom installation structure as described in claim 3, characterized in that, Each double-hole hinge plate has a first connecting hole and a second connecting hole. The first connecting holes on the two double-hole hinge plates are coaxially corresponding. The hinge rod is rotatably connected to the double-hole hinge plate by a pin. The second connecting holes on the two double-hole hinge plates are coaxially corresponding and are together sleeved on the truss chord of the auxiliary arm.

5. The large floating crane auxiliary boom installation structure as described in claim 1, characterized in that, The upper bracket and the lower bracket have the same structure, each including two vertical plates and one horizontal plate; wherein, the horizontal plate of the upper bracket is fixedly connected to the lower end of the two vertical plates, and the horizontal plate of the lower bracket is fixedly connected to the upper end of the two vertical plates.

6. The large floating crane auxiliary boom installation structure as described in claim 5, characterized in that, The two vertical plates of the upper bracket and the two vertical plates of the lower bracket are both right-angled trapezoidal plates; one right-angled side of the right-angled trapezoidal plate is fixedly connected to the horizontal plate, and the other right-angled side is fixedly connected to the main body or the auxiliary arm.

7. The large floating crane auxiliary boom installation structure as described in claim 6, characterized in that, The upper bracket is fixed on the side of the docking end face of the auxiliary arm, and the lower bracket is fixed on the docking end face of the main body. In the installation and support state, the horizontal plate of the upper bracket and the horizontal plate of the lower bracket are face to face and fit together, and the two vertical plates of the upper bracket and the two vertical plates of the lower bracket are perpendicular to each other, that is, the upper bracket and the lower bracket are arranged at a 90° intersection.

8. A method for installing a large floating crane's auxiliary boom, implemented using the installation structure described in any one of claims 1-7, characterized in that, Includes the following steps: S1. During boom production, the articulated base and lower bracket are pre-installed in the corresponding positions of the main body; at the same time, the double-hole articulated component and upper bracket are pre-installed in the corresponding positions of the auxiliary boom. S2. When installing the auxiliary boom, use a floating crane to lift the auxiliary boom to the vicinity of the docking end face of the main body, and lower the auxiliary boom so that the upper bracket rests on the lower bracket to form a pressure support; S3. Then, the two ends of the hinge rod are rotatably connected to the hinge seat and the double-hole hinge piece respectively, so that the auxiliary arm and the main box form a temporary fixed state of upper hinge and lower support. S4. After confirming that the auxiliary boom is in a stable position, remove the floating crane equipment, weld the circumferential seam between the auxiliary boom and the main body to connect them into one unit, and complete the installation of the auxiliary boom.

9. The method for installing the auxiliary boom of a large floating crane as described in claim 8, characterized in that, Before removing the floating crane, the gap between the auxiliary boom and the main body is fine-tuned by using the rotational connection between the auxiliary boom and the main body through the hinge assembly. After confirming that the gap meets the welding process requirements, the floating crane is then removed.

10. The method for installing the auxiliary boom of a large floating crane as described in claim 8, characterized in that, After welding is completed, the hinge assembly and support bracket are not removed and are retained as permanent auxiliary support structures.

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