An installation process for adding bushings to marine cable guide holes

Abstract

An installation process for adding bushings to marine guide wire holes is disclosed. The guide wire hole is open at both ends, hollow inside, and has an elliptical cross-section. The guide wire hole narrows in the middle and widens at both ends, with an arc-shaped transition connection between the middle and the ends. Bushings are installed inside the guide wire hole, consisting of an inboard bushing and an outboard bushing, which are joined together to form a complete bushing. Rubber buoys are used to press the inboard and outboard bushings into the guide wire hole, respectively. The rubber buoy consists of a top cup section, a middle arc-shaped transition section, and a flared section at the stern. This invention provides convenient installation of bushings for guide wire holes, requiring no heat treatment. The bushing installation can be completed during the segmented assembly stage. The installed bushing is safe and reliable in use, easy to operate, maintenance-free, and meets relevant specifications.

Description

Technical Field

[0001] This invention belongs to the field of marine vessel design and construction, and specifically relates to an installation process for adding bushings to marine cable guide holes. Background Technology

[0002] Adding a bushing to the guide hole is a relatively new mooring aid that has emerged in recent years and is favored and widely used by foreign shipowners, especially on large container ships and bulk carriers. Because mooring on container and bulk carriers is frequent and each mooring session is relatively long, the cables wear and break due to constant friction against the guide hole during loading and unloading. Previously, ships used roller guides instead of guide holes to avoid premature cable wear. While the rollers in roller guides can roll with the cable, reducing friction and wear compared to the hard friction of the cable on the guide hole, the bending radius of the rollers is much smaller than the surface of the guide hole, resulting in a smaller bending radius of the cable on the rollers, thus still leading to rapid cable wear.

[0003] Adding a bushing to the guide hole involves installing a smooth, low-friction, hard bushing (note: this bushing is made of a material similar to hard resin and is used on guide holes using nylon cables; it cannot be used on guide holes for towing mooring with wire ropes, as the bushing will be scratched and damaged by the wire ropes). Because the bushing's coefficient of friction is much lower than that of the guide hole, it reduces friction and wear on the cable. Simultaneously, given the large bending radius of the guide hole itself, the bending radius of the cable passing through it is also large, further reducing cable wear. The combination of these two advantages reduces the wear and replacement costs of nylon cables, making the guide hole and bushing combination a popular new mooring method among shipowners in recent years. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an installation process for adding bushings to marine guide cable holes, aiming to reduce installation difficulty. The technical solution adopted is as follows:

[0005] An installation process for adding bushings to a marine guide cable hole is disclosed. The guide cable hole is open at both ends, hollow inside, and has an elliptical cross-section. The guide cable hole narrows in the middle and expands outward at both ends. The middle and end are connected by an arc-shaped transition. A bushing is installed inside the guide cable hole. The bushing is divided into an inboard bushing and an outboard bushing. The inboard bushing and the outboard bushing are mated to form a complete bushing. The inboard bushing and the outboard bushing have the same structure.

[0006] Use a rubber float to press the bushing into the cable guide hole. The rubber float consists of a top cup section, a middle arc-shaped transition section, and a tail flared section. The top cup section has an eye plate in the middle, and a fiber rope is attached to the eye plate. The arc of the middle arc-shaped transition section matches the arc of the cable guide hole, but its size is slightly larger than the cable guide hole. The specific installation steps are as follows:

[0007] S1. During the assembly of sections in the shipbuilding process or before the ship is launched, the guide holes need to be installed. Each guide hole for installing bushings on the ship needs to be marked with the corresponding bushing model. Preparations need to be made for each guide hole before installation, such as setting up scaffolding on the outside of the ship and cleaning and polishing the guide holes.

[0008] S2: Use a fiber optic rope to pass through the inboard bushing. First, pre-install the inboard bushing. Use a crane to lift the inboard bushing above the guide hole and slowly lower it. The inboard bushing falls into the guide hole from one end. The top of the rubber buoy pushes into the inboard bushing from the outside. Pull the fiber optic rope from the other side of the inboard bushing. The fiber optic rope moves the rubber buoy. The friction between the rubber buoy and the bushing presses the bushing into the guide hole. Continue until the inboard bushing moves to halfway into the guide hole. Then, use the same method to pre-install the outboard bushing. Press the outboard bushing into the guide hole until it is halfway into the guide hole. After both the inboard and outboard bushings are installed, use clamps to clamp and fix the inboard and outboard bushings.

[0009] S3: Check whether the gap between the outer bushing and the inner bushing is within the required range, and check whether the gaps at the edges of the outer bushing and the inner bushing are within the required range.

[0010] S4: Pre-install the inner and outer bushing fastening bolts. Pass the nut sleeve through the bolt fixing hole sleeve on the inner and outer bushings, then pass the hex bolt through the sleeve and tighten the hex bolt with a wrench to fit the inner and outer bushings together.

[0011] S5: Unscrew the hex bolts and remove them, loosen the clamps, remove the inner bushing and outer bushing, apply glue to the contact area between the inner bushing, outer bushing and the inner surface of the cable guide hole, and press the inner bushing and outer bushing into the cable guide hole according to the operation of step S2.

[0012] After the bushings are positioned, the inner bushing and the outer bushing are connected by hex bolts. The gap between the inner bushing and the outer bushing is also filled with glue. The gaps between the edge of the inner bushing, the edge of the outer bushing and the guide hole are also filled with glue. The curing time of the glue is at least 24 hours.

[0013] The above-mentioned installation process for adding a bushing to a marine cable guide hole involves an elliptical cross-section of the arc-shaped transition section in the middle of the rubber float, which matches the arc of the middle of the cable guide hole. The outer dimensions of the rubber float must be larger than the inner diameter of the bushing in the middle so that the bushing can be pressed into the cable guide hole using the rubber float.

[0014] Furthermore, in the above-mentioned installation process for adding bushings to marine cable guide holes, the gap between the outer bushing and the inner bushing after installation is less than 24mm, and the gap between the edge of the inner bushing, the perimeter of the edge of the outer bushing, and the cable guide hole is less than 15mm.

[0015] Furthermore, in the above-mentioned installation process for adding bushings to marine cable guide holes, the preload of the hexagonal bolts must not exceed 40 Nm.

[0016] Furthermore, in step S5, the above-mentioned installation process for adding bushings to marine cable guide holes involves applying glue evenly and continuously to the curved surfaces of the inner and outer bushings that contact the cable guide hole using a glue gun, with a thickness of 5mm.

[0017] Furthermore, in the above-mentioned installation process of adding bushings to marine guide holes, during the installation of the inboard and outboard bushings, it is ensured that the inboard and outboard bushings are vertically inserted into the guide hole, and that the nuts and sleeves of the outboard and inboard bushings are vertical.

[0018] Furthermore, in the above-mentioned installation process of adding bushings to marine cable guide holes, the inner surface of the cable guide hole needs to be polished to a smooth surface and cleaned of oil stains before pre-installation.

[0019] Furthermore, in the above-mentioned installation process of adding bushings to marine cable guide holes, there are six nut sleeves, which are evenly spaced along the circumference of the inner bushing and the outer bushing.

[0020] Furthermore, in the above-mentioned installation process for adding bushings to marine cable guide holes, the clamp is square with an opening on one side and is an elastic clamp with an inward bending.

[0021] The cable guide hole of this invention is equipped with a bushing for easy installation without the need for heat treatment. The bushing can be installed during the segmented assembly stage. The installed bushing is safe and reliable in use, easy to operate and maintenance-free, and meets the relevant specifications. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the cross-section of the cable guide hole;

[0023] Figure 2 This is a schematic diagram of the rubber float structure;

[0024] Figure 3 This is a schematic diagram of the installation using rubber floats;

[0025] Figure 4 This is a schematic diagram of the clamps used to secure the inner and outer hull bushings.

[0026] Among them, 1-cable guide hole, 2-shield, 3-hexagonal bolt, 4-clamp, 5-rubber float, 6-eye plate. Detailed Implementation

[0027] The invention will be further described with reference to the accompanying drawings.

[0028] An installation process for adding bushings to marine guide holes, wherein the guide hole is open at both ends and hollow inside, such as... Figure 1 As shown, the cross-section is elliptical, and its size varies depending on actual needs. Commonly used guide hole cross-section sizes are 350x250mm, 400x250mm, 450x250mm, 500x250mm, etc. This description uses a 450x250mm guide hole as an example. The cross-section of guide hole 1 is viewed from the side as a curved surface, tapering in the middle and expanding outward at both ends. The middle and the upper and lower ends are connected by an arc-shaped transition. A bushing 2 is installed inside the guide hole. The bushing is divided into an inboard bushing and an outboard bushing. The inboard bushing and the outboard bushing are mated to form a complete bushing. A rubber float 5 is used to press the bushing into the guide hole.

[0029] The internal and external bushings have the same structure, such as... Figure 2 As shown, the rubber float consists of a top cup section, a middle arc-shaped transition section, and a tail flared section. An eye plate 6 is welded in the middle of the top cup section, and a fiber rope is attached to the eye plate. The arc of the middle arc-shaped transition section matches the arc of the cable guide hole. The outer diameter of the top of the rubber float is larger than the inner diameter of the middle of the bushing, but smaller than the inner diameter of the middle of the cable guide hole.

[0030] The specific installation steps are as follows:

[0031] S1. First, determine the installation stage of the bushing. It is recommended to install the guide hole during the sectional assembly stage of the ship's construction process or before the ship is launched. At this time, a crane can be used to lift the guide hole for installation. It is strongly discouraged to install the bushing after the ship has finished its voyage and docked. Although this time period is beneficial for the protection of the bushing after installation, there is no crane on the other side of the ship away from the shore to help lift the heavy bushing and lower it onto the guide hole, making the installation very difficult.

[0032] S2. Since the bushings added to the guide holes can only be installed on guide holes using nylon cables and not on guide holes used for towing mooring with wire ropes (the bushings will be scratched and damaged), each guide hole on the ship must be marked before the bushings are installed, and guide holes with bushings installed and those without bushings must be distinguished and marked.

[0033] S3. Given that the bushings added to the cable guide holes are custom-made in advance, that is, in order to perfectly fit the arc curve changes on the cable guide holes, each bushing is customized according to the specification model of the corresponding cable guide hole. Therefore, before the bushings are installed, each cable guide hole on the ship that needs to be installed must be marked with the model and other characteristics of each corresponding bushing.

[0034] S4. Pre-installation preparations. Establish temporary access points for the cable guide holes where bushings need to be installed, such as by erecting scaffolding and hanging safety nets, to ensure that installers can safely access the front and back sides of the cable guide holes to carry out related work.

[0035] Inspect the cable guide holes for which bushings need to be installed, checking for any unevenness or raised SWL markings. Grind and smooth the cable guide hole surface if necessary. Ensure the cable guide hole surface is clean and free of oil stains or dirt. Unpack and inspect the incoming bushings to check for any damage. Prepare the crane and lifting ropes for the bushing installation process. Attach the ropes to the corresponding bushings for lifting. Do not use steel wire ropes or other hard materials to lift the bushings to avoid scratching them.

[0036] S5. To avoid the inability to modify bushings due to size discrepancies after formal installation, pre-installation of the bushings is mandatory. First, pre-install the inboard bushing. Pass a fiber optic cable through the bushing and use a crane to lift the inboard bushing above the guide hole, then slowly lower it until it is inside the guide hole. Use a rubber buoy to push the inboard bushing in from the outside, and then pull the buoy from the other side of the inboard bushing until the bushing is halfway into the guide hole. Figure 3 As shown.

[0037] The same procedure is followed for the outer liner: the rubber float is used to press the outer liner into the guide hole until it reaches halfway into the guide hole.

[0038] S6, after the outer and inner bushings are in place, use clamp 4 to fix the positions of the inner and outer bushings, such as... Figure 4 As shown, the clamp is square with an opening on one side and consists of an inwardly curved elastic clip. Check for large gaps around the bushing edge and between it and the cable guide hole, as well as large gaps between the inner and outer bushings.

[0039] S7. Pre-install the inboard and outboard guide hole fastening bolts. First, pass a nut sleeve through the bolt fixing hole on the bushing, then pass the hex bolt 3 through the nut sleeve. Tighten the bolt with a wrench. The maximum preload of the bolt should not exceed 40 Nm. Tighten the bolt to fit the two guide hole bushings together. Check for large gaps between the guide hole bushings. The gap between the edge of the guide hole and the perimeter of the inboard and outboard bushings should generally be less than 15 mm. The maximum gap between the outboard and inboard bushings should be less than 24 mm.

[0040] S8. Unscrew and remove the hex bolts, then remove the inner guide hole bushing. Loosen the clamps, remove the outer guide hole bushing, and place it in a safe area on the deck in preparation for actual assembly.

[0041] S9. Formal Installation: Follow the steps in S5 to formally install the inner and outer bushings. However, during this formal installation, adhesive needs to be applied to the surface of the bushing where it contacts the guide hole. Use a glue gun to apply the adhesive evenly and continuously to a thickness of 5mm, ensuring the curved surface of the bushing in contact with the guide hole is fully covered with adhesive.

[0042] After applying the adhesive, use rubber floats to press the outer and inner bushings into their installation positions, ensuring the bushings are vertical and aligned. Ensure all six nut sleeves are vertical and not tilted. Once positioned, connect and tighten the inner and outer bushings using a wrench and hex bolts. The preload of the hex bolts should not exceed 40 Nm.

[0043] After connection, the gap between the inner and outer bushings is also filled with glue, as are the gaps between the edges of the inner and outer bushings and the guide holes. The glue should be applied as evenly and neatly as possible. After the bushings are installed, the glue should cure for at least 24 hours, and for an additional 1-2 days in cold winter conditions.

Claims

1. An installation process for adding bushings to marine cable guide holes, characterized in that, The cable guide hole is open at both ends, hollow inside, and has an elliptical cross-section. The cable guide hole narrows in the middle and expands outward at both ends. The middle and end are connected by an arc-shaped transition. A bushing is installed inside the cable guide hole. The bushing is divided into an inboard bushing and an outboard bushing. The inboard bushing and the outboard bushing are joined together to form a complete bushing. The inboard bushing and the outboard bushing have the same structure. The bushing is pressed into the cable guide hole using a rubber float. The rubber float consists of a top cup section, a middle arc-shaped transition section, and a tail flared section. The top cup section has an eye plate in the middle, and a fiber rope is attached to the eye plate. The arc of the middle arc-shaped transition section matches the arc of the cable guide hole. The specific installation steps are as follows: S1. During the assembly of sections in the shipbuilding process or before the ship is launched, the guide cable holes need to be marked. Each guide cable hole for installing bushings needs to be marked with the corresponding bushing model. Each guide cable hole needs to be cleaned and polished before installation. S2: Use a fiber rope to pass through the inboard bushing. First, pre-install the inboard bushing. Use a crane to lift the inboard bushing above the guide hole and slowly lower it. The inboard bushing falls into the guide hole from one end. The top of the rubber buoy pushes into the inboard bushing from the outside. Pull the fiber rope from the other side of the inboard bushing. The fiber rope drives the rubber buoy. The friction between the rubber buoy and the bushing presses the bushing into the guide hole. Continue until the inboard bushing moves to halfway into the guide hole. Then, use the same method to pre-install the outboard bushing. Press the outboard bushing into the guide hole until it is halfway into the guide hole. After both the inboard and outboard bushings are installed, use clamps to fix the outboard bushing. S3: Check whether the gap between the outer bushing and the inner bushing is within the required range, and check whether the gaps at the edges of the outer bushing and the inner bushing are within the required range. S4: Pre-install the inner and outer bushing fastening bolts. Pass the nut sleeve through the bolt fixing hole sleeve on the inner and outer bushings, then pass the hex bolt through the sleeve and tighten the hex bolt with a wrench to fit the inner and outer bushings together. S5: Unscrew the hex bolts and remove them, loosen the clamps, remove the inner bushing and outer bushing, apply glue to the contact area between the inner bushing, outer bushing and the inner surface of the cable guide hole, and press the inner bushing and outer bushing into the cable guide hole according to the operation of step S2. After the bushings are positioned, the inner bushing and the outer bushing are connected by hex bolts. The gap between the inner bushing and the outer bushing is also filled with glue. The gaps between the edge of the inner bushing, the edge of the outer bushing and the guide hole are also filled with glue. The curing time of the glue is at least 24 hours.

2. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, The cross-section of the arc-shaped transition section in the middle of the rubber float is elliptical, which matches the arc of the middle of the cable guide hole. The outer dimensions of the rubber float need to be larger than the inner diameter of the middle of the bushing so that the bushing can be pressed into the cable guide hole using the rubber float.

3. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, The gap between the outer bushing and the inner bushing after installation is less than 24mm, and the gap between the edge of the inner bushing, the perimeter of the edge of the outer bushing and the guide hole is less than 15mm.

4. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, The maximum preload of a hex bolt should not exceed 40 Nm.

5. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, In step S5, glue is applied evenly and continuously to the curved surfaces of the inner and outer bushings that contact the cable guide hole using a glue gun, with a thickness of 5mm.

6. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, During the installation of the inboard and outboard bushings, ensure that the inboard and outboard bushings are vertically inserted into the cable guide hole, and ensure that the nut sleeves of both the inboard and outboard bushings are vertical.

7. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, Before pre-installation, the inner surface of the cable guide hole must be polished to a smooth surface and cleaned of oil stains; scaffolding must be erected on the outer side of the cable guide hole before installation.

8. The installation process for adding bushings to marine cable guide holes according to claim 6, characterized in that, There are six nut sleeves, which are evenly spaced along the circumference of the inner and outer bushings.

9. The installation process for adding bushings to marine cable guide holes according to claim 1, characterized in that, The clamp is square with an opening on one side and is a flexible clamp that bends inward.

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