A method of hoisting a transom door

Abstract

The present application belongs to the technical field of shipbuilding, and discloses a stern ramp hoisting method, wherein the stern ramp comprises a first plate body and a second plate body, and the method comprises the following steps: a first hoist hoists the first end of the first plate body, a second hoist hoists the second end of the first plate body, a third hoist hoists the second end of the second plate body, the whole stern ramp is hoisted to a target height, the positions of the first hoist, the second hoist and the third hoist are adjusted, the first plate body and the second plate body are folded and attached around the hinge point in the air, neither the first hoist nor the third hoist is subjected to a pulling force, the second hoist lowers the folded and attached stern ramp to the ground, the first hoist and the third hoist are disconnected from the first plate body and the second plate body respectively, and then the second hoist hoists the stern ramp to the ship body. The method can fold the stern ramp in the air, effectively simplifies the construction process, is convenient for transportation, does not involve the disassembly and assembly of the stern ramp, and effectively improves the operation efficiency.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to a method for hoisting a stern ramp. Background Technology

[0002] The stern ramp is a key component of a transport ship, used to connect the hull to the shore to enable the ship's roll-on / roll-off (Ro-Ro) function. Specifically, the stern ramp is assembled from multiple panels and requires extensive on-shore testing to ensure reliable operation before it can be installed onto the hull.

[0003] In related technologies, the transportation process of stern ramps generally involves: first, disassembling the stern ramp into multiple panels on the ground; stacking these panels sequentially and connecting them with steel wire ropes; then using hoisting equipment such as gantry cranes to lift the stacked panels onto the ship's hull; and finally, reassembling the panels onto the hull to form the stern ramp and positioning it within the ship. While this process meets the transportation and installation requirements of stern ramps, it involves disassembling, stacking, and assembling the ramps, resulting in a complex construction process and low operational efficiency. After the stern ramps are disassembled and stacked, the work of connecting adjacent panels with axles using hoisting equipment is extensive, and collisions and interference between the panels and axles or other accessories can easily occur, posing risks of component damage and safety. Furthermore, the reassembly process on the ship's hull also occupies space and support resources, hindering the reassembly process. Summary of the Invention

[0004] The purpose of this invention is to provide a method for hoisting a stern ramp, which can fold the stern ramp in mid-air, effectively simplifying the construction process, facilitating transportation, and eliminating the need for disassembly and assembly of the stern ramp, thereby effectively improving operational efficiency.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A method for hoisting a stern ramp, the stern ramp comprising a first plate and a second plate, wherein a second end of the first plate is hinged to a first end of the second plate, the method comprising the following steps:

[0007] S100, the first lifting device lifts the first end of the first plate, the second lifting device lifts the second end of the first plate, and the third lifting device lifts the second end of the second plate, together lifting the stern ramp as a whole to the target height;

[0008] S200. Adjust the positions of the first lifting device, the second lifting device, and the third lifting device so that the first plate and the second plate are folded and attached together in the air around the hinge point, and neither the first lifting device nor the third lifting device is subjected to any tensile force.

[0009] S300, the second lifting device lowers the folded and fitted stern ramp to the ground, and the first lifting device and the third lifting device respectively disconnect the first plate and the second plate;

[0010] S400, the second lifting device lifts the folded and fitted stern ramp onto the hull.

[0011] Preferably, in step S100, the distance between the target height and the ground is at least 10m.

[0012] Preferably, in step S100, the first and second lifting devices are configured as gantry cranes, and the third lifting device is configured as a crawler crane.

[0013] Preferably, in step S100, the distance between the third lifting device and the stern ramp is at least 3m.

[0014] Preferably, a plurality of first lifting lugs are fixed to the first end of the first plate, a plurality of second lifting lugs are fixed to the second end of the first plate, and a plurality of third lifting lugs are fixed to the first end of the second plate. The first lifting lugs, the second lifting lugs, and the third lifting lugs are all used for threading lifting cables.

[0015] Preferably, step S200 includes:

[0016] S210, The second lifting device rises relative to the first lifting device and the third lifting device to lift the second end of the first plate, so that the first plate and the second plate swing downward around the hinge point to the first state position;

[0017] S220. The third lifting device descends relative to the second lifting device and places the second end of the second plate, causing the second plate to swing downward around the hinge point to the second state position until the third lifting device is no longer subject to tension.

[0018] S230, the first lifting device lowers relative to the second lifting device to place the first end of the first plate, so that the first plate swings downward around the hinge point to the third state position until the first lifting device is no longer under tension, and finally the first plate and the second plate are folded and attached in the air.

[0019] Preferably, when in the first state position, the angle between the first plate and the second plate is 90°; when in the second state position, the angle between the first plate and the second plate is 45°; and when in the third state position, the angle between the first plate and the second plate is 0°.

[0020] Preferably, in step S300, multiple pad groups are spaced apart on the ground, and the folded and fitted stern ramp is lowered and supported on the multiple pad groups.

[0021] Preferably, the pad group can be set by stacking 1-3 layers of pads, and the height of the pad group does not exceed 3m.

[0022] Preferably, the first plate is provided with a hinge part for hinged to the hull. In step S400, the third lifting device adjusts the position of the stern ramp so that the hinge part is adjusted to face the hull.

[0023] Beneficial effects:

[0024] The stern ramp hoisting method provided by this invention involves firstly, a first, second, and third lifting device lifting the first end, the second end, and the second end of the first and second ramps, respectively, together raising the entire stern ramp to the target height. Then, by adjusting the positions of the first, second, and third lifting devices, the first and second ramps are folded and fitted together in mid-air around their hinge points, with neither the first nor third lifting devices experiencing any tensile force, the tensile force being completely transferred to the second lifting device. Next, the second lifting device is lowered, lowering the folded and fitted stern ramp to the ground. The first and third lifting devices are then disengaged, detaching them from the first and second ramps, respectively. Finally, the folded and fitted stern ramp is hoisted onto the ship's hull using the second lifting device again. The above method allows the stern ramp to be folded in mid-air, effectively simplifying the construction process, facilitating transportation, and avoiding the disassembly and assembly of the stern ramp. This effectively improves operational efficiency, avoids the complicated operations involved in disassembling and stacking the stern ramp, reduces the risk of component damage, and enhances practicality and safety. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the stern ramp hoisting method provided by the present invention;

[0026] Figure 2 This is a schematic diagram of the stern ramp in its deployed state provided by the present invention;

[0027] Figure 3 This is a schematic diagram of step S100 of the stern ramp hoisting method provided by the present invention;

[0028] Figure 4 This is a schematic diagram of step S210 of the stern ramp hoisting method provided by the present invention;

[0029] Figure 5 This is a schematic diagram of step S220 of the stern ramp hoisting method provided by the present invention;

[0030] Figure 6 This is a schematic diagram of step S230 of the stern ramp hoisting method provided by the present invention;

[0031] Figure 7 This is a schematic diagram of the stern ramp being supported on the pad block assembly in step S300 of the stern ramp hoisting method provided by the present invention;

[0032] Figure 8 This is a schematic diagram of the removal of the first and third lifting tools in step S300 of the stern ramp hoisting method provided by the present invention;

[0033] Figure 9 This is a schematic diagram of the second lifting device lifting the stern ramp in step S400 of the stern ramp hoisting method provided by the present invention;

[0034] Figure 10 This is a schematic diagram of the stern ramp being hoisted onto the hull in step S400 of the stern ramp hoisting method provided by the present invention.

[0035] In the picture:

[0036] 1. Stern ramp; 11. First board; 111. First lifting lug; 112. Second lifting lug; 113. Hinge; 12. Second board; 121. Third lifting lug;

[0037] 2. First lifting device;

[0038] 3. Second lifting device;

[0039] 4. Third lifting device;

[0040] 5. Hull;

[0041] 6. Pad block assembly. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0043] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0045] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0046] This invention provides a method for hoisting a stern ramp 1. (Refer to...) Figures 1 to 10 As shown, the stern ramp 1 includes a first plate 11 and a second plate 12, with the second end of the first plate 11 hinged to the first end of the second plate 12. See details... Figure 2 As shown, the first plate 11 includes one plate, and the second plate 12 includes two plates, meaning the stern ramp 1 comprises three plates. Since the two plates of the second plate 12 are not separated during subsequent operations, they will be collectively referred to as the second plate 12 in the following description of this embodiment.

[0047] Specifically, the hoisting method for the stern ramp 1 includes the following steps:

[0048] S100, the first lifting device 2 lifts the first end of the first plate 11, the second lifting device 3 lifts the second end of the first plate 11, and the third lifting device 4 lifts the second end of the second plate 12, together lifting the stern ramp 1 as a whole to the target height;

[0049] S200. Adjust the positions of the first lifting device 2, the second lifting device 3 and the third lifting device 4 so that the first plate 11 and the second plate 12 are folded and attached in the air around the hinge point, and the first lifting device 2 and the third lifting device 4 are not subject to the pulling force.

[0050] S300, the second lifting device 3 lowers the folded and fitted stern ramp 1 to the ground, and the first lifting device 2 and the third lifting device 4 respectively disconnect the first plate 11 and the second plate 12;

[0051] S400 and the second lifting device 3 hoist the folded and fitted stern ramp 1 onto the hull 5.

[0052] In this embodiment, the first lifting device 2, the second lifting device 3, and the third lifting device 4 firstly lift the first end of the first plate 11, the second end of the first plate 11, and the second end of the second plate 12, respectively. Together, they lift the stern ramp 1 to the target height. Then, by adjusting the positions of the first lifting device 2, the second lifting device 3, and the third lifting device 4, the first plate 11 and the second plate 12 are folded and fitted together in mid-air around the hinge point, with the first lifting device 2 and the third lifting device 4 not subjected to any pulling force, and the pulling force being completely transferred to the second lifting device 3. Next, the second lifting device 3 is lowered to place the folded and fitted stern ramp 1 to the ground. The first lifting device 2 and the third lifting device 4 are then removed, detaching them from the first plate 11 and the second plate 12, respectively. Finally, through a second lifting operation by the second lifting device 3, the folded and fitted stern ramp 1 is hoisted onto the hull 5. The above method can fold the stern ramp 1 in mid-air, which effectively simplifies the construction process, facilitates transportation, and does not involve the disassembly and assembly of the stern ramp 1, effectively improving operational efficiency, avoiding the complicated operations in the process of disassembling and stacking the stern ramp 1, reducing the risk of component damage, and also improving practicality and safety.

[0053] In this embodiment, in step S100, the first lifting device 2 and the second lifting device 3 are configured as gantry cranes, and the third lifting device 4 is configured as a crawler crane. Specifically, in this embodiment, the stern ramp 1 has a lifting weight of 285t, and the total weight including the lifting platform is 314t.

[0054] For example, the first lifting device 2 and the second lifting device 3 are configured as gantry cranes with a maximum load capacity of 600t, and the third lifting device 4 is configured as a crawler crane with a maximum load capacity of 400t.

[0055] Specifically, a plurality of first lifting lugs 111 are fixed to the first end of the first plate 11, a plurality of second lifting lugs 112 are fixed to the second end of the first plate 11, and a plurality of third lifting lugs 121 are fixed to the first end of the second plate 12. The first lifting lugs 111, second lifting lugs 112, and third lifting lugs 121 are all used for the installation of lifting cables. The lifting cables are steel wire ropes, and the lifting cables are installed through the first lifting lugs 111, second lifting lugs 112, and third lifting lugs 121 for lifting by the first lifting device 2, the second lifting device 3, and the third lifting device 4.

[0056] For example, a plurality of first lifting lugs 111 are spaced apart along the width direction of the stern ramp 1, a plurality of second lifting lugs 112 are spaced apart along the width direction of the stern ramp 1, and a plurality of third lifting lugs 121 are spaced apart along the width direction of the stern ramp 1.

[0057] For example, the number of first lifting lugs 111 is set to four, the number of second lifting lugs 112 is set to eight, and the number of third lifting lugs 121 is set to four. In this embodiment, the second lifting lugs 112 serve as the main subsequent lifting and docking components, and are therefore more numerous and stronger, with each second lifting lug 112 requiring a weight of 36t.

[0058] In this embodiment, in step S100, the distance between the target height and the ground is at least 10m. This setting allows the stern ramp 1 to be a certain distance from the ground, facilitating its subsequent bending in the air and avoiding interference from the ground. For example, the distance between the target height and the ground is 10m, 12m, or 15m.

[0059] In this embodiment, in step S100, the distance between the third lifting device 4 and the stern ramp 1 is at least 3m. This arrangement ensures a reliable safety distance between the crawler crane and the stern ramp 1 when the third lifting device 4 is a crawler crane, preventing the second plate of the stern ramp 1 from colliding with the crawler crane during lifting and swinging. For example, the distance between the third lifting device 4 and the stern ramp 1 can be 3m, 4m, or 5m.

[0060] In this embodiment, step S200 includes:

[0061] S210, the second lifting device 3 rises relative to the first lifting device 2 and the third lifting device 4 to lift the second end of the first plate 11, so that the first plate 11 and the second plate 12 swing downward around the hinge point to the first state position simultaneously;

[0062] S220, the third lifting device 4 descends relative to the second lifting device 3 and lowers the second end of the second plate 12, so that the second plate 12 swings downward around the hinge point to the second state position until the third lifting device 4 is no longer under tension.

[0063] S230, the first lifting device 2 descends relative to the second lifting device 3 and lowers the first end of the first plate 11, so that the first plate 11 swings downward around the hinge point to the third state position until the first lifting device 2 is no longer under tension, and finally the first plate 11 and the second plate 12 are folded and attached in the air.

[0064] Specifically, in step S210, the second lifting device 3 slowly rises, lifting the second end of the first plate 11, thereby allowing the first plate 11 and the second plate 12 to swing downwards simultaneously around the hinge point. During this process, the first lifting device 2 and the third lifting device 4 continue to exert a pulling force on the first plate 11 and the second plate 12. In step S220, the first lifting device 2 and the second lifting device 3 remain temporarily stationary, while the third lifting device 4 descends relative to the second lifting device 3, thereby lowering the second end of the second plate 12. Under its own weight, the second plate 12 swings downwards around the hinge point to the second state position, ultimately freeing the third lifting device 4 from the pulling force. In step S230, the second lifting device 3 remains stationary, and the first lifting device 2 descends relative to the second lifting device 3, thereby lowering the first end of the first plate 11. Under its own weight, the first plate 11 swings downward around the hinge point to the third state position, so that the first lifting device 2 is also not subject to the pulling force, and finally the second lifting device 3 achieves effective pulling of the stern ramp 1.

[0065] Specifically, in this embodiment, when in the first state position, the angle between the first plate 11 and the second plate 12 is 90°. In the first state position, the angle between the first plate 11 and the vertical direction is 45°, and the angle between the second plate 12 and the vertical direction is 45°. When in the second state position, the angle between the first plate 11 and the second plate 12 is 45°. In the second state position, the second plate 12 is completely lowered to a vertical position. When in the third state position, the angle between the first plate 11 and the second plate 12 is 0°. In the second state position, the first plate 11 is also completely lowered to a vertical position, thereby achieving the folding and fitting of the first plate 11 and the second plate 12 in mid-air.

[0066] In this embodiment, in step S300, multiple pad groups 6 are spaced apart on the ground. After the folded and fitted stern ramp 1 is lowered, it is supported on the multiple pad groups 6. The pad groups 6 provide reliable support for the stern ramp 1, serving as support and buffer, and preventing the stern ramp 1 from making direct hard contact with the ground. For example, the pad groups 6 are made of wood. Specifically, the pad groups 6 can be stacked in 1-3 layers, and the height of the pad groups 6 does not exceed 3m. After the stern ramp 1 is supported in place on the pad groups 6, the first lifting device 2 and the third lifting device 4 are removed, so that the first lifting device 2 and the third lifting device 4 are respectively disconnected from the first plate 11 and the second plate 12. In addition, the hook of the second lifting device 3 can unload 20t-30t.

[0067] In this embodiment, the first plate 11 is provided with a hinge portion 113 for hinged connection with the hull 5. In step S400, the third lifting device 4 adjusts the position of the stern ramp 1 so that the hinge portion 113 is adjusted to face the side of the hull 5. This arrangement ensures that after the stern ramp 1 is lifted onto the hull 5, the hinge portion 113 can directly face the side where the hull 5 is located, facilitating the subsequent direct connection between the stern ramp 1 and the hull 5, reducing the steps required for significant positional adjustments of the stern ramp 1 on the hull 5, and simplifying the subsequent installation process.

[0068] In summary, the stern ramp 1 hoisting method provided in this embodiment can fold the stern ramp 1 in mid-air, effectively simplifying the construction process, facilitating transportation, and eliminating the need for disassembly and reassembly of the stern ramp 1, thus significantly improving operational efficiency. Specifically: this method does not involve re-threading the axles between the various sections of the stern ramp 1 after disassembly, reducing operational difficulty; this method folds the stern ramp 1 in mid-air and directly hoists it onto the ship, eliminating the need for temporary alignment and reassembly on the hull 5; because this method does not involve disassembly and reassembly of the stern ramp 1, there will be no interference or collision between the sections, preventing damage to accessories and paint; this method eliminates the need for temporary welding reinforcement connections, ensuring good paint on the stern ramp 1 and avoiding high-altitude operations such as temporary reinforcement removal, thus reducing safety risks.

[0069] Furthermore, practical experience shows that using this method can save one week of installation and commissioning time for the stern ramp 1, resulting in economic benefits of approximately 15 people × 8 hours × 50 yuan × 7 days = 42,000 yuan; reduce gantry crane usage time by 24 hours, resulting in economic benefits of approximately 24 hours × 1,300 yuan / hour = 31,200 yuan; and save on site and temporary support equipment costs, resulting in economic benefits of approximately 2.5 yuan / m² × 884 m² × 7 days = 15,470 yuan; total economic benefits: 42,000 + 31,200 + 15,470 = 88,670 yuan. In addition, using this method, the stern ramp 1 can be folded within 3 hours, allowing for rapid installation in subsequent processes, saving at least one week compared to traditional methods. Other implicit benefits of improved quality are also unpredictable, with a conservative estimate of over 100,000 yuan in economic benefits per vessel.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for hoisting a stern ramp, used for a stern ramp (1), the stern ramp (1) comprising a first plate body (11) and a second plate body (12), wherein the second end of the first plate body (11) is hinged to the first end of the second plate body (12), characterized in that, The stern ramp hoisting method includes the following steps: S100, the first lifting device (2) lifts the first end of the first plate (11), the second lifting device (3) lifts the second end of the first plate (11), and the third lifting device (4) lifts the second end of the second plate (12), together lifting the stern ramp (1) to the target height; S200. Adjust the positions of the first lifting device (2), the second lifting device (3) and the third lifting device (4) so ​​that the first plate (11) and the second plate (12) are folded and attached in the air around the hinge point, and the first lifting device (2) and the third lifting device (4) are not subject to the pulling force. S300, the second lifting device (3) lowers the folded and fitted stern ramp (1) to the ground, and the first lifting device (2) and the third lifting device (4) respectively disconnect the first plate (11) and the second plate (12); S400, the second lifting device (3) lifts the folded and fitted stern ramp (1) onto the hull (5); Step S200 includes: S210, the second lifting device (3) rises relative to the first lifting device (2) and the third lifting device (4) to lift the second end of the first plate (11), so that the first plate (11) and the second plate (12) swing downward around the hinge point to the first state position simultaneously; S220, the third lifting device (4) lowers relative to the second lifting device (3) to place the second end of the second plate (12), so that the second plate (12) swings downward around the hinge point to the second state position until the third lifting device (4) is no longer subject to the pulling force; S230, the first lifting device (2) lowers relative to the second lifting device (3) to place the first end of the first plate (11), so that the first plate (11) swings down around the hinge point to the third state position until the first lifting device (2) is no longer under tension, and finally the first plate (11) and the second plate (12) are folded and attached in the air; When in the first state position, the angle between the first plate (11) and the second plate (12) is 90°; when in the second state position, the angle between the first plate (11) and the second plate (12) is 45°; when in the third state position, the angle between the first plate (11) and the second plate (12) is 0°.

2. The stern ramp hoisting method according to claim 1, characterized in that, In step S100, the distance between the target height and the ground is at least 10m.

3. The stern ramp hoisting method according to claim 1, characterized in that, In step S100, the first lifting device (2) and the second lifting device (3) are configured as gantry cranes, and the third lifting device (4) is configured as a crawler crane.

4. The stern ramp hoisting method according to claim 3, characterized in that, In step S100, the distance between the third lifting device (4) and the stern ramp (1) is at least 3m.

5. The stern ramp hoisting method according to claim 1, characterized in that, The first plate (11) has a plurality of first lifting lugs (111) fixed at its first end, a plurality of second lifting lugs (112) fixed at its second end, and a plurality of third lifting lugs (121) fixed at its first end. The first lifting lugs (111), the second lifting lugs (112) and the third lifting lugs (121) are all used for the installation of lifting cables.

6. The stern ramp hoisting method according to claim 1, characterized in that, In step S300, multiple pad groups (6) are spaced apart on the ground. After the folded and fitted stern ramp (1) is lowered, it is supported on the multiple pad groups (6).

7. The stern ramp hoisting method according to claim 6, characterized in that, The pad block group (6) can be set by stacking 1-3 layers of pad blocks, and the height of the pad block group (6) does not exceed 3m.

8. The stern ramp hoisting method according to claim 1, characterized in that, The first plate (11) is provided with a hinge part (113) for hinged to the hull (5). In step S400, the second lifting device (3) adjusts the position of the stern ramp (1) so that the hinge part (113) is adjusted to face the hull (5).

Images