Mounting process for adding lining to marine fairlead

Abstract

According to the installation technology for adding the bushings to the marine fairlead, the two ends of the fairlead are open, the interior of the fairlead is hollow, the cross section of the fairlead is oval, the middle of the fairlead shrinks, the two ends of the fairlead expand outwards, the middle and the ends of the fairlead are in arc-shaped transition connection, the bushings are installed in the fairlead and comprise the inboard bushings and the outboard bushings, and the inboard bushings and the outboard bushings are in butt joint to form the complete bushings. A rubber floating ball is used for pressing the inboard lining and the outboard lining into the fairlead, and the rubber floating ball is composed of a ball bowl section at the top, an arc-shaped transition section in the middle and a horn mouth section at the tail. The bushings are added to the fairlead, installation is convenient, hot working is not needed, installation of the bushings can be completed in the segment folding stage, the installed bushings are safe and reliable in use, convenient to operate and free of maintenance, and corresponding standard requirements are met.

Description

Technical Field

[0001] The invention belongs to the field of marine ship design and construction, and in particular relates to an installation process for adding a bushing to a ship fairlead hole. Background Art

[0002] Adding a bushing on the fairlead is a new mooring auxiliary device that has emerged in recent years. It is more popular and applied by foreign shipowners, especially on large container ships and bulk carriers. Since the mooring of containers and bulk carriers is very frequent and the mooring time is long each time, the cable will constantly rub against the fairlead during loading and unloading, causing wear and breakage. In the past, ships used roller fairleads instead of fairleads to avoid the cable from wearing too quickly. Although the roller of the roller fairlead can roll with the movement of the cable, the rolling roller reduces the friction and wear on the cable compared to the hard friction of the cable on the fairlead, but because the bending radius of the roller is much smaller than the surface of the fairlead, the bending radius of the cable on the roller is also small, and there is still the problem of fast cable wear.

[0003] Add a bushing to the fairlead, and install a smooth hard bushing with a low friction coefficient on the fairlead (Note: the material of the bushing is similar to hard resin, and it is used on the fairlead using nylon cables, and cannot be used on the fairlead using wire ropes for towing mooring, as the bushing will be scratched and damaged by the wire rope). Since the friction coefficient of the bushing is much lower than that of the fairlead, the friction and wear of the fairlead on the cable is reduced; at the same time, given the large bending radius of the fairlead itself, the bending radius of the cable passing through it is also large, which can further reduce the wear of the cable. The combination of these two advantages reduces the wear and replacement cost of nylon cables, making the combination of fairlead and bushing a new mooring method favored by shipowners in recent years. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an installation process for adding a bushing to a ship fairlead hole, aiming to reduce the difficulty of installation. The technical solution adopted is: The invention discloses an installation process for adding a bushing to a ship fairlead hole. The fairlead hole is open at both ends and hollow inside. Its cross section is elliptical. The middle part of the fairlead hole shrinks and the two ends expand outward. The middle part and the end parts are connected by an arc transition. A bushing is installed in the fairlead hole. The bushing is divided into an inboard bushing and an outboard bushing. The inboard bushing and the outboard bushing are butt-jointed to form a complete bushing. The inboard bushing and the outboard bushing have the same structure.

[0005] Use a rubber float to press the bushing into the fairlead hole. The rubber float consists of a ball bowl section at the top, an arc-shaped transition section in the middle, and a bell-mouth section at the tail. There is an eye plate in the middle of the ball bowl section at the top, and a fiber rope is fastened to the eye plate. The arc-shaped transition section in the middle has an arc that matches the arc in the middle of the fairlead hole, but the size is one circle larger than the fairlead hole. The specific installation steps are as follows: S1. During the stage of assembling the sections in the shipbuilding process or installing the fairleads before the ship is launched, it is necessary to mark each fairlead on the ship where the bushing is installed, and mark the corresponding bushing model. It is necessary to prepare each fairlead before installation, such as setting up scaffolding on the outside of the ship's side, cleaning and polishing the fairleads, etc.

[0006] S2: Use the fiber rope to pass through the inboard bushing, pre-install the inboard bushing first, lift the inboard bushing to the top of the fairlead hole with a crane and slowly lower it, the inboard bushing falls into the fairlead hole from one end of the fairlead hole, the top of the rubber float is pushed in from the outside of the inboard bushing, pull the fiber rope from the other side of the inboard bushing, the fiber rope drives the rubber float, the friction between the rubber float and the bushing presses the bushing into the fairlead hole until the inboard bushing moves to the half of the fairlead hole; then use the same method to pre-install the outboard bushing, press the outboard bushing into the fairlead hole until it is half of the fairlead hole, after the inboard bushing and the outboard bushing are installed, use the clamp to clamp and fix the inboard and outboard bushings.

[0007] S3: Check whether the gap between the outboard bushing and the inboard bushing is within the required range, and check whether the gap between the edge of the outboard bushing and the edge of the inboard bushing is within the required range.

[0008] S4: Pre-install the inboard bushing and outboard bushing fastening bolts, pass the nut sleeve through the bolt fixing hole sleeves on the inboard bushing and outboard bushing, then pass the hexagonal bolt through the sleeve, use a wrench to tighten the hexagonal bolt to fit the inboard bushing and outboard bushing together.

[0009] S5: Unscrew the hexagonal bolt and remove it, loosen the clamp, remove the inboard bushing and the outboard bushing, apply glue to the contact between the inboard bushing and the outboard bushing and the inner surface of the fairlead hole, and press the inboard bushing and the outboard bushing into the fairlead hole according to the operation of step S2; After positioning the bushing, connect the inboard bushing and the outboard bushing with hexagonal bolts. The gap between the inboard bushing and the outboard bushing is also filled with glue. The gap between the edge of the inboard bushing, the edge of the outboard bushing and the fairlead hole is also filled with glue. The curing time of the glue is at least 24 hours.

[0010] In the above-mentioned installation process for adding a bushing to a ship fairing hole, the cross-section of the arc-shaped transition section in the middle of the rubber float is elliptical, which is compatible with the middle arc of the fairing hole. The outer size of the rubber float needs to be larger than the inner diameter of the bushing in the middle so that the rubber float can be used to press the bushing into the fairing hole.

[0011] The above-mentioned installation process for adding a bushing to a ship fairlead hole further has the following advantages: the gap between the outboard bushing and the inboard bushing after installation is less than 24 mm, and the gaps around the edge of the inboard bushing and the edge of the outboard bushing and the fairlead hole are less than 15 mm.

[0012] In the above-mentioned installation process of adding a bushing to a ship fairlead, further, the maximum pre-tightening force of the hexagonal bolt cannot exceed 40Nm.

[0013] The above-mentioned installation process for adding a bushing to a ship fairing hole further comprises, in step S5, using a glue gun to evenly and continuously apply glue in a thickness of 5 mm on the curved surfaces of the inboard bushing and the outboard bushing that are in contact with the fairing hole.

[0014] The above-mentioned installation process for adding a bushing to a ship fairlead hole further ensures that the inboard bushing and the outboard bushing vertically enter the fairlead hole during the installation of the inboard bushing and the outboard bushing, and ensures that the nuts and sleeves of the outboard bushing and the inboard bushing are both vertical.

[0015] The above-mentioned installation process of adding a bushing to a ship fairlead hole further requires that the inner surface of the fairlead hole be polished to be smooth and cleaned of oil stains before pre-installation.

[0016] The above-mentioned installation process of adding a bushing to a ship fairlead hole further comprises six nut sleeves which are arranged at equal intervals along the circumference of the inboard bushing and the outboard bushing.

[0017] The above-mentioned installation process for adding a bushing to a ship fairlead hole further comprises the following steps: the clamp is square, has an opening on one side, and is an elastic clip with an inward bend.

[0018] The cable guide hole of the present invention is easy to install with a bushing, and does not require heat processing. The bushing can be installed in the stage of segment closing. The installed bushing is safe and reliable in use, easy to operate and maintenance-free, and meets the corresponding specification requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the cross section of the fairlead hole; Figure 2 It is a schematic diagram of the rubber float structure; Figure 3 It is a schematic diagram of installation using a rubber float; Figure 4 It is a schematic diagram of fixing the inboard bushing and the outboard bushing with a clamp; Among them, 1-fairlead hole, 2-bushing, 3-hexagonal bolt, 4-clamp, 5-rubber float, 6-eye plate. DETAILED DESCRIPTION

[0020] The present invention will be further described in conjunction with the accompanying drawings.

[0021] A process for installing a sleeve on a ship's fairlead hole, wherein the fairlead hole is open at both ends and hollow inside. Figure 1As shown, the cross section is elliptical, and the size of the fairlead hole has various specifications according to actual needs. The cross-sectional dimensions of the common fairlead holes are 350x250mm, 400x250mm, 450x250mm, 500x250mm, etc. This description takes the fairlead hole of 450x250mm as an example. The cross section of the fairlead hole 1 is a curved surface when viewed from the side, with the middle part shrinking and the upper and lower ends expanding outwards. The middle part and the upper and lower ends are connected by an arc transition. A bushing 2 is installed in the fairlead hole. The bushing is divided into an inboard bushing and an outboard bushing. The inboard bushing and the outboard bushing are connected to form a complete bushing. The bushing is pressed into the fairlead hole using a rubber float 5.

[0022] The structure of the inboard bushing and the outboard bushing is the same, such as Figure 2 As shown, the rubber float consists of a ball bowl section at the top, an arc-shaped transition section in the middle and a flared section at the tail. An eye plate 6 is welded in the middle of the ball bowl section at the top, and a fiber rope is fastened to the eye plate. The arc-shaped transition section in the middle has an arc that matches the arc in the middle 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, and smaller than the inner diameter of the middle of the cable guide hole.

[0023] The specific installation steps are as follows: S1, first determine the installation stage of the bushing. It is recommended to install the fairlead during the stage of assembling the sections during the ship construction process or before the ship is launched. During this period, there is a crane that can be used to lift the fairlead for installation. It is strongly not recommended to install the bushing after the ship has finished sailing and docked. Although this period is conducive to the protection of the bushing after installation, there is no crane on the other side of the ship away from the shore, and the heavy bushing cannot be lifted and dropped on the fairlead, making the installation very difficult.

[0024] S2. Considering that the bushing added to the fairlead can only be installed on the fairlead using nylon cable, and cannot be used on the fairlead using wire rope for towing mooring (the bushing will be scratched and damaged), each fairlead on the ship needs to be marked before the bushing is installed, and the fairleads with and without bushings installed need to be distinguished and marked.

[0025] S3. Considering that the bushing added to the fairlead is customized in advance, that is, in order to fully fit the arc curve change on the fairlead, each bushing is customized according to the specification model of the corresponding fairlead. Therefore, before the bushing is installed, each fairlead that needs to be installed on the ship needs to be marked with the model and other characteristics of each corresponding bushing.

[0026] S4, pre-installation preparation. Set up a temporary passage for the fairing hole where the bushing needs to be installed, such as setting up scaffolding and hanging safety nets, to ensure that the installers can safely reach the front and back sides of the fairing hole to carry out related work.

[0027] Check the relevant fairlead holes where bushings need to be installed to see if there are any uneven spots. If there are any raised SWL marks, they need to be polished and trimmed until the surface of the fairlead holes is smooth. Check to ensure that the surface of the fairlead holes is clean and free of oil stains. Unpack and inspect the incoming bushings to confirm whether the bushings are damaged. Prepare the crane and fiber rope for lifting during the installation of the bushings, and put the fiber rope on the corresponding bushings for lifting. Do not use hard materials such as wire ropes to lift the bushings to avoid scratching the bushings.

[0028] S5, in order to avoid the bushing being found to be inappropriate and unable to be modified after formal installation, the bushing must be pre-installed. Pre-install the inboard bushing first, pass the fiber rope through the bushing, lift the inboard bushing to the top of the fairlead with a crane and slowly lower it, drop the inboard bushing into the inside of the fairlead; push the rubber float from the outside of the inboard bushing, pull the rubber float from the other side of the inboard bushing to press the bushing into the half position of the fairlead and stop, such as Figure 3 shown.

[0029] The outboard bushing is also operated in the same way, using a rubber float to press the outboard bushing into the fairlead hole until it is halfway through the fairlead hole.

[0030] S6, after the outboard bushing and the inboard bushing are in place, use the clamp 4 to fix the position of the inboard bushing and the outboard bushing, such as Figure 4 As shown, the clamp is square with an opening on one side and an elastic clip with an inward bend. Check whether there is a large gap around the edge of the bushing and between the fairlead hole, and whether there is a large gap between the inboard bushing and the outboard bushing.

[0031] S7, pre-install the fastening bolts of the inboard and outboard fairlead holes, first pass the nut sleeve through the bolt fixing hole on the bushing, then pass the hexagonal bolt 3 through the nut sleeve, tighten the bolt with a wrench, the maximum pre-tightening force of the bolt should not exceed 40Nm, tighten the bolts to fit the two fairlead bushings together. Check whether there is a large gap between the fairlead bushings. The gap between the edge of the fairlead hole and the edges around the inboard bushing and the outboard bushing is generally less than 15mm, and the maximum gap between the outboard bushing and the inboard bushing is less than 24mm.

[0032] S8, unscrew the hexagon bolt and remove it, remove the inboard fairlead bushing. Loosen the clamp, remove the outboard fairlead bushing and place it in a safe area on the deck in preparation for the actual assembly.

[0033] S9, formal installation, follow the steps in S5 to formally install the inboard bushing and outboard bushing, but this time you need to apply glue on the surface of the bushing that contacts the fairlead. Use a glue gun to apply glue evenly and continuously at a thickness of 5 mm, and cover the bushing surface that contacts the fairlead with glue.

[0034] After applying the glue, use the rubber float to press the outboard bushing and the inboard bushing into the installation position respectively, confirm that the bushing is vertical, the outboard bushing and the inboard bushing should be aligned, and ensure that the six nut sleeves are vertical without tilt. After positioning, connect and tighten the inboard bushing and the outboard bushing with a wrench and hexagonal bolts. The maximum pre-tightening force of the hexagonal bolts cannot exceed 40Nm.

[0035] After the connection is completed, the gap between the inboard bushing and the outboard bushing is also filled with glue, and the gap between the edge of the inboard bushing, the edge of the outboard bushing and the fairlead hole is also filled with glue. The glue should be applied as evenly and neatly as possible. After the bushing is installed, the curing time of the glue is at least 24 hours, and it can be extended by 1-2 days in winter when the temperature is low.

Claims

1. A process for installing a sleeve in a ship fairlead hole, characterized in that: The fairlead hole is open at both ends, hollow inside, and has an elliptical cross section. The middle of the fairlead hole shrinks and the two ends expand outwards. The middle and the ends are connected by an arc transition. A bushing is installed in the fairlead hole. The bushing is divided into an inboard bushing and an outboard bushing. The inboard bushing and the outboard bushing are butt-jointed to form a complete bushing. The inboard bushing and the outboard bushing have the same structure. Use a rubber float to press the bushing into the fairlead hole. The rubber float consists of a ball bowl section at the top, an arc-shaped transition section in the middle, and a bell-mouth section at the tail. There is an eye plate in the middle of the ball bowl section at the top, and a fiber rope is fastened to the eye plate. The arc of the arc-shaped transition section in the middle matches the arc of the fairlead hole. The specific installation steps are as follows: S1. During the assembly of the sections during ship construction or the installation of fairleads before the ship is launched, each fairlead on board where a bushing is installed needs to be marked, and the corresponding bushing model needs to be marked. Each fairlead needs to be cleaned and polished before installation; S2: Use the fiber rope to pass through the inboard bushing, pre-install the inboard bushing first, lift the inboard bushing to the top of the fairlead hole with a crane and slowly lower it, the inboard bushing falls into the fairlead hole from one end of the fairlead hole, the top of the rubber float is pushed in from the outside of the inboard bushing, pull the fiber rope from the other side of the inboard bushing, the fiber rope drives the rubber float, the friction between the rubber float and the bushing presses the bushing into the fairlead hole, when the inboard bushing moves to the half of the fairlead hole; then use the same method to pre-install the outboard bushing, press the outboard bushing into the fairlead hole, until the half of the fairlead hole, after the inboard bushing and the outboard bushing are installed, use a clamp to fix the outboard bushing; S3: Check whether the gap between the outboard bushing and the inboard bushing is within the required range, and check whether the gap between the edge of the outboard bushing and the edge of the inboard bushing is within the required range; S4: Pre-install the inboard bushing and outboard bushing fastening bolts, pass the nut sleeve through the bolt fixing hole sleeves on the inboard bushing and outboard bushing, then pass the hexagonal bolt through the sleeve, tighten the hexagonal bolt with a wrench to fit the inboard bushing and outboard bushing together; S5: Unscrew the hexagonal bolt and remove it, loosen the clamp, remove the inboard bushing and the outboard bushing, apply glue to the contact between the inboard bushing and the outboard bushing and the inner surface of the fairlead hole, and press the inboard bushing and the outboard bushing into the fairlead hole according to the operation of step S2; After positioning the bushing, connect the inboard bushing and the outboard bushing with hexagonal bolts. The gap between the inboard bushing and the outboard bushing is also filled with glue. The gap between the edge of the inboard bushing, the edge of the outboard bushing and the fairlead hole is also filled with glue. The curing time of the glue is at least 24 hours.

2. The installation process of adding a bushing to a ship fairlead 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 is compatible with the middle curvature of the fairlead hole. The outer size of the rubber float needs to be larger than the middle inner diameter of the bushing so that the bushing can be pressed into the fairlead hole using the rubber float.

3. The installation process of adding a bushing to a ship fairlead according to claim 1, characterized in that: The gap between the outboard bushing and the inboard bushing after installation is less than 24mm, and the gap between the edge of the inboard bushing, the edge of the outboard bushing and the fairlead hole is less than 15mm.

4. The installation process of adding a bushing to a ship fairlead according to claim 1, characterized in that: The maximum preload force of the hexagonal bolts shall not exceed 40 Nm.

5. The installation process of adding a bushing to a ship fairlead according to claim 1, characterized in that: In step S5, glue is evenly and continuously applied to the curved surfaces of the inboard bushing and the outboard bushing in contact with the fairlead hole using a glue gun in a thickness of 5 mm.

6. The installation process of adding a bushing to a ship fairlead according to claim 1, characterized in that: During the installation of the inboard bushing and the outboard bushing, make sure that the inboard bushing and the outboard bushing enter the fairlead hole vertically, and ensure that the nut sleeves of the outboard bushing and the inboard bushing are both vertical.

7. The installation process of adding a bushing to a ship fairlead according to claim 1, characterized in that: Before pre-installation, the inner surface of the fairlead hole needs to be polished to be smooth and cleaned of oil stains; before installation, scaffolding should be set up on the outer side of the fairlead hole.

8. The installation process for adding a bushing to a ship fairlead according to claim 6, characterized in that: There are six nut sleeves which are arranged at equal intervals along the circumference of the inboard bushing and the outboard bushing.

9. The installation process for adding a bushing to a ship fairlead according to claim 1, characterized in that: The clamp is square with an opening on one side and is an elastic clip with an inward bend.

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