A pre-assembly method of a large ship lift

Abstract

The application discloses a pre-assembly method of a large-scale ship lift, and the pre-assembly method comprises the following steps: step S1, ship lift platform positioning; step S2, ship lift platform expansion amount compensation; step S3, main beam support pre-assembly; step S4, butt flange matching welding between ship lift platforms; step S5, butt flange bolt installation; step S6, platform cantilever beam installation; step S7, platform cantilever beam boring; step S8, ship lift platform working position pre-assembly; step S9, main beam deflection, platform length, width, overall flatness, platform camber detection and data analysis; step S10, after the bolts are removed, packing and transportation to an actual working position, and additional wrapping protection is carried out on the flange plate, the cantilever beam and the sliding wheel pin shaft during the packing. The application simulates fulcrum support in actual working conditions, so as to test platform deflection and other parameters, correct the parameters in advance when the parameters are out of tolerance, and avoid serious consequences such as uneven or eccentric screw holes.

Description

Technical Field

[0001] This invention relates to the field of marine engineering shipyard maintenance equipment, specifically to a pre-assembly method for a large ship lift. Background Technology

[0002] Traditionally, shipbuilding and ship repair in shipyards are often carried out in dry docks. However, due to the long time span of shipbuilding and repair, fixed dry dock dimensions, and low dock turnover rates, shipyards often face the predicament of having orders but no available dock space, making production impossible. Ship lifts, as a crucial tool in modern shipyards, play a vital role in improving dock turnover rates and reducing costs. When a ship needs repair, the ship lift platform (hereinafter referred to as the platform) is submerged in water. Ships enter the platform, and the lift lifts the ship to be repaired. The ship is then transferred to a dry berth for repair work via a transfer system. Once the ship has been repaired or manufactured, its launching is achieved by reversing the process.

[0003] As the core component of the ship lift, the ship lift platform mainly bears the load of the ship to be transferred and plays a vital role in the ship lift system.

[0004] For large ship lift platforms exceeding 200m in length, which are typically located near the sea or water with large temperature differences between day and night, even if the ship lift is made of steel with a low coefficient of thermal expansion, the overall expansion error can still exceed 50mm. This will inevitably affect the distance between the moving pulley of each platform and the orifice, causing the relative position of the moving pulley of a single platform and its corresponding fixed pulley of the locking beam to shift. Consequently, the wire rope may derail from the groove due to excessive deflection angle, affecting the installation and operation of the ship lift platform and even causing safety accidents.

[0005] Furthermore, the individual platform sections of a large ship lift are typically connected and fixed using flange plates and connecting bolts. The flange plates are fixed to the ends of the platform's cantilever beams, and are mostly welded to the ship lift platform. Ensuring that the flange plates and bolt holes at each joint are aligned after the ship lift platform supports are completed, minimizing or eliminating the impact of welding deformation, and ensuring smooth bolt insertion is a current challenge.

[0006] To address these technical issues, a pre-assembly method for large ship lifts is proposed. Summary of the Invention

[0007] The technical problem solved by this invention is that in the prior art, large ship lift platforms, especially those with a length exceeding 200m, have large overall expansion errors due to the large temperature difference between day and night. This affects the distance between the moving pulleys of each ship lift platform and the orifice, which in turn causes the relative positional offset between the moving pulleys of a single ship lift platform and its corresponding fixed pulleys on the locking beam, or even causes the platform to derail. In addition, it also makes it difficult to ensure that the flange plates and bolt holes are not affected by welding deformation, resulting in high alignment difficulty.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a pre-assembly method for a large ship lift, wherein the large ship lift includes several ship lift platforms that are spliced ​​together, and adjacent ship lift platforms are spliced ​​together by flange plates and connecting bolts between platform joints; each of the ship lift platforms has a platform cantilever beam extending outward in a horizontal direction fixed at both ends, and the lower surface of the platform cantilever beam has a pin hole recessed upward, in which a sliding wheel and a sliding wheel pin are installed; it also includes a support seat for supporting the sliding wheel pin, and a platform support pier set at the bottom of the ship lift platform for auxiliary support of the ship lift platform; The pre-assembly method includes the following steps: Step S1: Positioning of the ship lift platform; Step S2, compensation for the expansion of the ship lift platform, includes: calculating the longitudinal overall expansion Al and the transverse overall expansion Ah of the ship lift platform based on the actual temperature at the construction site; calculating the longitudinal expansion A1*Ln / L of each ship lift platform according to the longitudinal overall expansion Al, the total length L of the platform, and the length Ln of each platform; calculating the transverse expansion Ah / 2 of the ship lift platform; reducing and cutting each platform according to its own longitudinal and transverse expansion; grinding the cut edges after cutting and welding the flaps. Step S3: Pre-assembly of main beam supports; Step S4: Welding of the connecting flanges between the ship lift platforms; Step S5: Install the flange bolts. Step S6: Install the platform cantilever beam; Step S7: Boring the cantilever beam of the platform; Step S8: Pre-assembly of the ship lift platform working position; Step S9: Detection and data analysis of main beam deflection, platform length and width, overall flatness, and platform camber; Step S10: After removing the bolts, pack and transport the product to the actual work location. When packing, pay attention to providing extra protection for the flange plate, cantilever beam, and sliding wheel pin.

[0009] Specifically, step S1 includes: prefabricating sufficient support seats and platform piers in advance according to the number of sections of the ship lift platform and the number of cantilever beams on one side of the platform; calculating the positions of the support seats and platform piers according to the positions of the platform cantilever beams; using a total station to conduct surveying and layout; adjusting the position and elevation of the platform piers and temporarily fixing them; marking the corresponding platform number on the platform piers; and marking the position of the support seats.

[0010] Specifically, step S3 includes: using a truck crane to hoist the platform supports according to the platform support positions in step S1, and temporarily fixing the platform supports; using a large crane to hoist the ship lift platform onto the platform supports one by one in the arrangement sequence, and ensuring that the platform supports support the lower flange plate of the main beam of the ship lift platform.

[0011] Specifically, step S4 includes: according to the reserved installation position after the adjacent ship lift platforms are hoisted in step S3, first spot weld the sides of two flange plates, then drop the two spot-welded flange plates from the top of the platform and place them in the reserved position, spot weld the two flange plates to the longitudinal beams of the ship lift platforms on both sides respectively, after the position of the two flange plates is adjusted and confirmed, weld the two flange plates to the longitudinal beams of the ship lift platforms on both sides respectively, grind off the side weld points of the flange plates, release the welding stress and observe the welding deformation. If the deformation exceeds the limit, repeat step S4 until the welding deformation is compliant.

[0012] Specifically, step S5 includes: installing bolts according to the position of the installed flange plate joint; checking for misalignment, twisting, and warping of the flange bolt holes before installation; if misalignment, twisting, or warping exists, adjusting using the guide cone pin method; the guide cone pin method specifically includes: pre-inserting guide cone pins at diagonal positions on the flange plate; correcting the alignment of the holes on the two flange plates by pushing the guide cone pins towards the opposite flange plate; and finally removing the guide cone pins.

[0013] Specifically, step S9 includes: measuring the deflection of the pre-assembled main beam, the length and width of the platform, the overall flatness, and the camber of the platform; and analyzing the causes of deviations based on the measurement results, and correcting the deviation points by flame heating, mechanical correction, or cutting correction.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. By adding a pre-assembly process, the support points in actual working conditions are simulated to check parameters such as platform deflection. Corrections are made in advance when the aforementioned parameters exceed the tolerance, avoiding serious consequences such as uneven bolt holes or eccentricity, and effectively ensuring the assembly quality of the ship lift platform.

[0015] 2. By using the butt flange welding method, the problem of misalignment of bolt holes at the joint of two adjacent ship lift platforms can be effectively avoided. This effectively avoids rework caused by similar problems during later assembly, effectively improves the convenience of later construction, increases construction efficiency, and shortens the construction cycle.

[0016] 3. Fully verify the impact of temperature difference on the thermal expansion of the ship lift platform, and propose corresponding correction coefficients and correction experience based on actual engineering experience, so as to lay a solid foundation and provide sufficient factual evidence for subsequent similar projects. Attached Figure Description

[0017] Figure 1 This is a top-down view of the ship lift structure.

[0018] Figure 2 This is a schematic diagram showing the positional relationship between the ship lift platform and the support pier.

[0019] Figure 3 This is a side view of a ship lift platform with a support base.

[0020] Figure 4 This is a schematic diagram of the cantilever beam structure of the platform.

[0021] Figure 5 This is a schematic diagram of the flange connection relationship.

[0022] Figure 6 This is a lateral schematic diagram of the flange connection relationship.

[0023] Figure 7 This is a flowchart of the present invention.

[0024] The labels in the diagram are as follows: ship lift platform—1; flange plate—2; platform cantilever beam—3; pin hole—4; movable pulley assembly—5; support base—6. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, so as to provide a better understanding of the concept of the present invention, the technical problem solved, the technical features constituting the technical solution, and the technical effects brought about.

[0026] like Figures 1-3 and Figure 7As shown, the present invention discloses a pre-assembly method for a large ship lift, comprising several ship lift platforms 1 spliced ​​together, adjacent ship lift platforms 1 being spliced ​​together by flange plates 2 and connecting bolts between platform joints; each of the ship lift platforms 1 has a platform cantilever beam 3 extending outward in a horizontal direction fixed at both ends, the lower surface of the platform cantilever beam 3 having a pin hole 4 recessed upward, and a movable pulley assembly 5 and a movable pulley pin installed in the pin hole 4; it also includes a support seat 6 for supporting the movable pulley pin, and a platform support pier disposed at the bottom of the ship lift platform 1 for auxiliary support of the ship lift platform 1.

[0027] The pre-assembly method includes the following steps: Step S1, positioning of ship lift platform 1; Step S2, compensation for expansion of ship lift platform 1; Step S3: Pre-assembly of main beam supports; Step S4: Welding of the connecting flanges between the ship lift platforms; Step S5: Install the flange bolts. Step S6: Install platform cantilever beam 3; Step S7: Boring the three holes in the platform cantilever beam; Step S8: Pre-assembly of the ship lift platform at work station 1; Step S9: Main beam deflection, platform length and width, overall flatness, platform camber and data analysis; Step S10: After removing the bolts, pack and transport the product to the actual work location. When packing, pay attention to providing extra protection for flange plate 2, cantilever beam, and movable pulley pin.

[0028] In one embodiment of the present invention, the ship lift, due to its size, weight, and load-bearing capacity exceeding those of conventional ship lifts, features a large steel structure, numerous welds, a large amount of welding, and high dimensional control precision. Whether post-weld deformation will affect the preset pre-camber is a key and challenging aspect of the project construction. If the maximum camber of a single platform cannot meet the design requirements after manufacturing, the deflection at the platform center will inevitably fail to meet design requirements when the ship lift bears its maximum rated load, leading to platform scrapping or significant expenditure of manpower and resources for correction, resulting in losses. The total length of the ship lift platform 1 reaches 245m, and the maximum diurnal temperature range at the project site reaches 39℃. Although the thermal expansion coefficient of steel is relatively small, its cumulative thermal expansion error can reach 56mm relative to the large-sized platform. The single platforms are fixed to each other by bolts. There are nearly 500 bolts at the joints of adjacent platforms, distributed on 25 flange connection plates, while the flange plates 2 are fixed to the ends of the platform longitudinal beams and welded to the platform.

[0029] In practical implementation, the harbor basin opening is a civil engineering concrete structure with a concave shape, providing sufficient space for the vertical movement of the ship lift platform 1. The ship lift platform 1 consists of 17 welded steel structures, connected by bolts. The two sides of the platform, together with pulley blocks, locking beams, and winches, form the lifting system. The platform cantilever beams 3 are welded components, protruding structures welded to both ends of the ship lift platform 1. Since the ship lift platform 1 has single-beam and double-beam variations, the corresponding platform cantilever beams 3 also have single-ended and double-ended variations.

[0030] like Figure 4 As shown, a movable pulley pin and movable pulley assembly 5 are installed on the pin hole 4 at the end of the cantilever beam 3 of the platform. This assembly work should be completed in advance in the yard. The support 6 is also a welded steel structure, and its function is to simulate the stress point under the actual working conditions of the ship lift platform 1, thereby improving the accuracy of the subsequent data measurement of the ship lift platform 1. Before the temporary tooling support is made, its load-bearing capacity needs to be considered, its structural strength needs to be verified, and a certain safety margin needs to be reserved. In this embodiment, the support 6 is made of Q345 steel, and the overall structure is processed after welding. There are two semi-circular brackets on it, the size of which is slightly larger than the outer diameter of the movable pulley pin, which facilitates the installation of the movable pulley pins on the cantilever beams 3 of the platform on both sides of the platform. The flange plate 2 is a connecting plate for connecting the end faces of adjacent platforms. It has several bolt holes distributed on it and is welded to the end of the longitudinal beam of the ship lift platform 1. The bolt holes on it are drilled to match the bolt holes on the connecting flange. The movable pulley pin, belonging to the movable pulley assembly 5, is installed in the pin hole 4 and is prevented from axial and radial movement by a retaining plate. The movable pulley is installed in the middle of the pin. The platform support is a welded steel structure component, placed under the main beam of the ship lift, serving a supporting and fixing function. This support is mainly used to support the main beam of the platform, facilitating the subsequent welding of the platform cantilever beam 3.

[0031] As a preferred technical solution, step S1 specifically includes: prefabricating sufficient support seats 6 and platform supports in advance according to the number of sections of the ship lift platform 1 and the number of cantilever beams on one side of the platform; calculating the positions of support seats 6 and platform supports according to the position of the cantilever beams 3 of the platform, using a total station to conduct measurement and layout, adjusting the position and elevation of the platform supports and temporarily fixing them, marking the corresponding platform number on the platform supports, and marking the position of support seats 6 at the same time.

[0032] In the aforementioned embodiment, the ship lift platform 1 comprises 17 pieces, numbered 1-17, in the same order as the actual working conditions. Among these 17 pieces of ship lift platform 1, some platforms have two cantilever beams 3 on one side, while others have a single cantilever beam. Based on the actual total number of cantilever beams, a corresponding number of support seats 6 and platform supports are fabricated. The platform supports are used to support the lower part of the main beam during the overall assembly of the platform before the cantilever beams 3 are welded. A total of 56 support seats 6 of this type are required. The platform supports are welded steel structures, made of Q235 steel, with a panel size of 1*1m and a height of 1m.

[0033] As a preferred technical solution, step S2 specifically includes: calculating the longitudinal overall expansion A1 and the transverse overall expansion Ah of the ship lift platform based on the actual temperature at the construction site; calculating the longitudinal expansion A1*Ln / L of each ship lift platform according to the longitudinal overall expansion A1, the total length L of the platform, and the length Ln of each platform; calculating the transverse expansion Ah / 2 of the ship lift platform; reducing and cutting each platform according to its own longitudinal and transverse expansion; grinding the cut edges after cutting; and welding the flaps.

[0034] In the aforementioned embodiment, since the overall length of the ship lift platform 1 is 245m, considering a temperature difference of 39°C, the shrinkage along the length of the ship lift platform 1 reaches 56mm. Due to the large temperature difference between summer and winter, the position of the platform's moving pulley pins along the length will change. Since temperature factors were not considered during initial manufacturing, all platforms were processed and manufactured according to the theoretical design dimensions. To compensate for this thermal expansion and contraction deformation, the design pre-calculates and distributes the 56mm deformation to each platform position, calculating the required reduction in width for each platform, and then symmetrically cutting both sides at half of this dimension. After cutting, the cut edges are ground, the flaps are welded, and the platform awaits pre-assembly at the main beam support position.

[0035] As a preferred technical solution, step S3 specifically includes: according to the platform support position in step S1, using a truck crane to hoist the platform support and temporarily fix the platform support; using a large crane to hoist the ship lift platform 1 one by one onto the platform support in the arrangement sequence, and ensuring that the platform support supports reach the lower flange of the main beam of the ship lift platform 1.

[0036] In the aforementioned embodiment, since the positions of the platform supports have been planned in advance in step S1, the corresponding platform supports can be placed in the corresponding positions using a truck crane and temporarily fixed. The platform supports are positioned approximately 500mm from the end of the lower flange of the main beam of the ship lift platform 1. At the contact points between the ship lift platforms 1, the platforms need to be tightly pressed together. Care should be taken during hoisting to avoid repeated adjustments later. Check whether the gap width is consistent and whether the verticality and flatness of the ship lift platform 1 meet the requirements. If not, the posture of the ship lift platform 1 needs to be adjusted to check the relevant parameters of the joint. When using a large crane to hoist the platform for pre-assembly, after the platform joints are basically aligned, it is necessary to check whether the position of the connecting flange is appropriate. If not, it needs to be modified in advance. After 17 platforms are continuously laid out and connected, the overall dimensions of the ship lift platform 1 can be checked and corrected.

[0037] As a preferred technical solution, step S4 specifically includes: according to the reserved installation position after the adjacent ship lift platform 1 is hoisted in step S3, first spot weld the sides of two flange plates 2, then drop the two spot-welded flange plates 2 from the top of the platform and place them in the reserved position, spot weld the two flange plates 2 to the longitudinal beams of the ship lift platform 1 on both sides respectively, after the position of the two flange plates 2 is adjusted and confirmed, weld the two flange plates 2 to the longitudinal beams of the ship lift platform 1 on both sides respectively, grind off the side weld points of the flange plates 2, release the welding stress and observe the welding deformation. If the deformation exceeds the limit, repeat step S4 until the welding deformation is compliant.

[0038] In the foregoing embodiments, such as Figures 5-6 As shown, due to the large size of the ship lift platform, the thicker plates, and the larger weld seams, the resulting welding deformation is also significant. To avoid this deformation affecting the installation of flange plate 2, the flange installation process was improved on-site. After step S3 was completed, according to the pre-reserved installation positions between the platforms, the sides of the two flange plates were first tack welded to make them a single unit. Then, the two flange plates 2 were lowered together from the top of the platform and placed in the pre-reserved positions. After tack welding for fixation, and once the two flange plates 2 were adjusted and confirmed, they could be welded to the beams at both ends of the partition joint. Then, the side weld points of the mating flange plates 2 were ground off to release welding stress, and the welding deformation was checked at the same time.

[0039] Because the flange plates are quite thick, attention must be paid to the welding sequence and current magnitude between them and the beams on both sides. Before welding, a Welding Procedure Specification (WPS) must be confirmed, and then strictly followed to avoid welding defects.

[0040] After welding is completed, check the amount of deformation after welding. If the amount of deformation exceeds the tolerance, remove the weld of the corresponding butt flange and repeat step S4 until it meets the tolerance.

[0041] As a preferred technical solution, step S5 specifically includes: installing bolts according to the joint position of the installed flange plate 2; before installation, checking for misalignment, twisting, and warping of the flange bolt holes; if misalignment, twisting, and warping exist, adjusting them using the guide cone pin method; the guide cone pin method specifically includes: pre-inserting guide cone pins at diagonal positions on the flange plate 2; correcting the alignment of the holes on the two flange plates 2 by pushing the guide cone pins towards the opposite flange plate 2; and finally removing the guide cone pins.

[0042] In the aforementioned embodiment, after the flange bolts are installed in step S5, the 17 ship lift platforms 1 have been connected as a whole. At this point, the wooden deck can be assembled, the top elevation of the wooden deck can be leveled, and the wooden deck can be sanded and corrected to meet the design requirements.

[0043] As a preferred technical solution, step S8 specifically includes: installing the prefabricated support base 6 according to the position marked in step 1, and using large lifting equipment to hoist the ship lift platform 1 onto the corresponding support base 6, so that the movable pulley pins on the cantilever beams 3 on both sides of the ship lift platform 1 sit in the semi-circular bracket of the support base 6, checking the joint gap of the ship lift platform 1, and making adaptive adjustments for larger gaps to ensure that the end faces of adjacent ship lift platforms 1 fit tightly, and then welding and fixing the cantilever beams 3 and the ship lift platform 1.

[0044] As a preferred technical solution, step S9 specifically includes: measuring the deflection of the pre-assembled main beam, the length and width of the platform, the overall flatness, and the camber of the platform; and analyzing the causes of deviations based on the measurement results, and correcting the deviation points by flame heating, mechanical correction, or cutting correction.

[0045] The overall method flowchart of the present invention is as follows: Figure 7 As shown. In the aforementioned embodiment, the purpose of pre-assembling the ship lift platform 1 is to simulate actual working conditions, check whether relevant parameters meet design requirements, further eliminate the impact of production and manufacturing errors, and verify the rationality of platform installation. Platform pre-camber data measurement involves measuring whether the pre-camber value of each platform main beam changes under working condition support position conditions. If it exceeds the tolerance, the corresponding cause needs to be found and rectified to ensure the platform pre-camber meets design requirements. In this example, the design requirement is that the allowable deflection value L / 1000 under rated load is L, where L is the span, i.e., a 45mm allowable deflection value. However, in this example, it is unloaded, with only the platform's self-weight causing the deflection. The influence caused by self-weight needs to be deducted to verify whether the pre-camber meets the conditions. Rectification methods often include flame heating, mechanical straightening, and cutting correction. Platform width and length measurement mainly measures and verifies the dimensional changes caused by the expansion and contraction of the platform steel structure due to temperature changes.

[0046] Due to the temperature difference of approximately 39℃ between summer and winter at the construction site, the thermal deformation along the 245m length of the platform is calculated to exceed 56mm. The gap between the port basin opening and the platform cantilever beam 3 is approximately 500mm. If platform 17 at the end shifts by 56mm, the center of the movable pulley on the platform cantilever will not coincide with the center of the fixed pulley on the locking beam by 56mm. When the platform is lifted to the maintenance position, the center distance between the movable and fixed pulleys will be 5520mm, causing the wire rope center to shift relative to the pulley groove, potentially leading to wire rope slippage and a safety accident. Therefore, thermal expansion was considered during the initial design of the ship lift platform 1. The 56mm expansion deformation was distributed progressively according to the corresponding positions of the 17 platform sections, reducing the width of each ship lift platform 1 section by a total of 56mm, ensuring reliable operation of the platform steel structure even at the highest temperatures.

[0047] After step S8 is completed, the temperature difference between the current assembly temperature and the platform manufacturing temperature can be measured. According to European standard BSEN1991-1-5, the thermal expansion change of the platform under the current temperature difference can be checked to see if it conforms to theoretical calculations. If it does not conform, the cause can be investigated, the corresponding formula improved, and a correction coefficient added. The change in platform width over a period of time can then be observed to see if it conforms to the effects of temperature changes. It is important to note that the cantilever beams 3 are not installed on the ship lift platforms 1 involved in steps S1 to S5. This is mainly to prevent welding deformation from affecting the installation position of the cantilever beams, thereby affecting the positioning accuracy of the pulley pins and the spacing differences between the ship lift platforms 1.

[0048] In step S7, the platform cantilever beam 3 is provided with a pin hole 4, which is used in conjunction with the movable pulley pin during platform operation. Due to platform welding manufacturing errors, platform cantilever beam 3 welding deformation, and inaccurate on-site positioning, it is difficult to guarantee the coaxiality of all pin holes 4 on the ship lift platform 1 if they are pre-machined. On the other hand, since the ship lift platform 1 is 45m wide and 245m long, no large machine tool is available to complete the machining in one operation, so on-site machining after welding is adopted.

[0049] During on-site boring, it is essential to ensure the stability of the ship lift platform 1 and prevent it from wobbling during machining. Secondly, after boring, it is crucial to ensure that the coaxiality of all platform cantilever beam 3 pin holes 4 is aligned with the same straight line and elevation. Simultaneously, it is necessary to ensure that the hole spacing on both sides of the platform matches the design values, thereby guaranteeing that all on-site machining values ​​meet the design requirements.

[0050] The terms "connection" and "fixing" appearing in the description of this invention can refer to fixed connection, processing and forming, welding, or mechanical connection. The specific meaning of the above terms in this invention should be understood according to the specific circumstances.

[0051] In the description of this invention, the terms "center," "upper," "lower," "horizontal," "inner," and "outer," etc., are used only to indicate the orientation or positional relationship for the convenience of describing this invention and to simplify the description, and do not indicate or imply a specific orientation that the device or element referred to must have, and therefore should not be construed as a limitation of this invention.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pre-assembly method for a large ship lift, characterized in that, The large ship lift includes several ship lift platforms (1) that are spliced ​​together. Adjacent ship lift platforms (1) are spliced ​​together by flange plates (2) and connecting bolts between platform joints. Each ship lift platform (1) has a platform cantilever beam (3) that extends outward in the horizontal direction at both ends. The lower surface of the platform cantilever beam (3) has a pin hole (4) recessed upward. A movable pulley assembly (5) and a movable pulley pin are installed in the pin hole (4). The lift also includes a support seat (6) for supporting the movable pulley pin and a platform support pier set at the bottom of the ship lift platform (1) for auxiliary support of the ship lift platform (1). The pre-assembly method includes the following steps: Step S1, Positioning of the ship lift platform (1); Step S2, ship lift platform (1) expansion compensation, including: calculating the longitudinal overall expansion Al and the transverse overall expansion Ah of the ship lift platform according to the actual temperature of the construction site; calculating the longitudinal expansion A1*Ln / L of each ship lift platform according to the longitudinal overall expansion Al, the total length of the platform L, and the length of each platform Ln, and calculating the transverse expansion Ah / 2 of the ship lift platform. Each platform is reduced and cut according to its own longitudinal and transverse expansion. After the cutting is completed, the cutting edge is ground and the flap is welded. Step S3: Pre-assembly of main beam supports; Step S4: Welding of the connecting flanges between the ship lift platforms; Step S5: Install the flange bolts. Step S6, platform cantilever beam (3) installation; Step S7, boring the platform cantilever beam (3); Step S8, pre-assembly of the ship lift platform (1) at the work station; Step S9: Main beam deflection, platform length and width, overall flatness, platform camber and data analysis; Step S10: After removing the bolts, pack and transport the product to the actual work location. When packing, the flange plate (2), cantilever beam, and pulley pin shaft need to be additionally wrapped and protected.

2. The pre-assembly method for a large ship lift as described in claim 1, characterized in that, Step S1 specifically includes: prefabricating sufficient support seats (6) and platform supports in advance according to the number of sections of the ship lift platform (1) and the number of cantilever beams on one side of the platform; calculating the positions of support seats (6) and platform supports according to the position of the cantilever beams (3) of the platform, using a total station to measure and lay out, adjusting the position and elevation of the platform supports and temporarily fixing them, marking the corresponding platform number on the platform supports, and marking the position of the support seats (6) at the same time.

3. The pre-assembly method for a large ship lift as described in claim 2, characterized in that, Step S3 specifically includes: according to the platform support position in step S1, using a truck crane to hoist the platform support and temporarily fix the platform support; using a large crane to hoist the ship lift platform (1) one by one onto the platform support in the arrangement order, and ensuring that the platform support supports reach the end of the lower flange of the main beam of the ship lift platform (1).

4. The pre-assembly method for a large ship lift as described in claim 3, characterized in that, Step S4 specifically includes: according to the reserved installation position after the adjacent ship lift platform (1) is hoisted in step S3, first spot weld the sides of two flange plates (2), then drop the two flange plates (2) that are spot welded together from the top of the platform and place them in the reserved position, spot weld the two flange plates (2) to the longitudinal beams of the ship lift platform (1) on both sides respectively, and after the position of the two flange plates (2) is adjusted and confirmed, weld the two flange plates (2) to the longitudinal beams of the ship lift platform (1) on both sides respectively, grind off the side weld points of the flange plates (2), release the welding stress and observe the welding deformation; if the deformation exceeds the limit, repeat step S4 until the welding deformation is compliant.

5. The pre-assembly method for a large ship lift as described in claim 1, characterized in that, Step S5 specifically includes: installing bolts according to the joint position of the installed flange plate (2), checking for misalignment, twisting and warping of the flange bolt holes before installation, and adjusting them using the guide cone pin method if misalignment, twisting and warping are present; the guide cone pin method includes the following: pre-driving guide cone pins at diagonal positions on the flange plate (2), correcting the alignment of the holes of the two flange plates (2) by pushing the guide cone pins towards the opposite flange plate (2), and finally removing the guide cone pins.

6. The pre-assembly method for a large ship lift as described in claim 1, characterized in that, Step S9 specifically includes: measuring the deflection of the pre-assembled main beam, the length and width of the platform, the overall flatness, and the camber of the platform; and analyzing the causes of deviations based on the measurement results, and correcting the deviation points by flame heating, mechanical correction, or cutting correction.

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