Medium to large lightweight pneumatic fenders

Abstract

To provide medium-to-large-sized lightweight pneumatic fenders that can meet the requirements of naval vessels. [Solution] The invention comprises an air-filled section into which air is filled, an inner rubber layer 120 provided to enclose the air-filled section, a reinforcing layer 130 provided on one surface of the inner rubber layer 120, and an outer rubber layer 140 formed on one surface of the reinforcing layer 130, wherein the reinforcing layer 130 comprises a first reinforcing layer 131 and a second reinforcing layer 132 laminated on the first reinforcing layer 131, and the second reinforcing layer 132 is made of aramid fiber.

Description

Technical Field

[0001] The present invention relates to a medium to large and lightweight pneumatic fender for application to ships that require mobility, speed, and agility.

Background Art

[0002] The pneumatic fender was devised to overcome the limitations of general rubber fenders. In a structure in the form of an airbag, the inside is filled with air, and it has excellent shock absorption, does not require special internal materials, and is also economically excellent. Such a pneumatic fender is installed on the side of a quay or dock related to a ship. When the ship approaches the shore or moors at the dock, the impact between the dock and the ship is buffered by the air pressure of the pneumatic fender, preventing damage to the dock and the ship.

[0003] On the other hand, as disclosed in Patent Document 1, the pneumatic fender cannot form the skin in a casting form at once and is made by attaching a plurality of pieces. Therefore, the materials of the skin overlap, resulting in increased thickness, excessive weight, and relatively high process costs. When applied to naval ships, there is a problem that the weight becomes excessively heavy, making it difficult to meet the levels required for conditions such as mobility, speed, and strategic agility in naval ships.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The objective of the present invention is to solve the above-mentioned problems and to provide a medium-to-large lightweight pneumatic fender that can meet the requirements of naval vessels by reducing the weight of conventional cords made of nylon fibers to aramid fibers. [Means for solving the problem]

[0006] To achieve the above objective, a medium-to-large lightweight pneumatic fender according to one embodiment of the present invention includes an air-filled section into which air is filled; an inner rubber layer provided so as to enclose the air-filled section; a reinforcing layer provided on one surface of the inner rubber layer; and an outer rubber layer formed on one surface of the reinforcing layer, wherein the reinforcing layer includes a first reinforcing layer and a second reinforcing layer laminated on the first reinforcing layer, and the second reinforcing layer is made of aramid fibers.

[0007] Here, the thickness of the second reinforcing layer may be 1.5 to 3 times the thickness of the first reinforcing layer.

[0008] Furthermore, the internal pressure of the air-filled section may be between 50 kPa and 80 kPa.

[0009] Furthermore, the sum of the thicknesses of the inner rubber layer and the outer rubber layer may be 8 mm or less.

[0010] The thickness of the inner rubber layer may be 0.5 to 1 times the thickness of the outer rubber layer.

[0011] Furthermore, the size of the fender may be in the range of 1,000 mm to 4,500 mm in diameter and 1,500 mm to 12,000 mm in length. [Effects of the Invention]

[0012] According to one embodiment of the present invention, medium- and large-sized lightweight pneumatic fenders can meet the requirements of naval vessels by achieving weight reduction through a reduction in thickness by changing the material from conventional cords made of nylon fibers to aramid fibers.

[0013] Furthermore, medium- and large-sized lightweight pneumatic fenders can reduce not only thickness and weight but also cost by optimizing the overlap of the inner and outer rubber layers. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view showing a medium-to-large lightweight pneumatic fender according to the present invention. [Figure 2] This is a schematic diagram showing a cross-section of A in one embodiment of Figure 1. [Figure 3] This is a manufacturing process diagram that provides a schematic explanation of the manufacturing method for medium- and large-sized lightweight pneumatic fenders. [Figure 4] This photograph shows the spacing between the vulcanization mold and the fender during the vulcanization process. [Figure 5] This is a schematic diagram showing the spacing between the vulcanization mold and the fender during the vulcanization process. [Figure 6] This is a photograph showing the results related to Experimental Example 1. [Figure 7] This is a photograph showing the results related to Experimental Example 1. [Modes for carrying out the invention]

[0015] The embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments disclosed below and can be realized in a variety of different forms, and these embodiments are provided merely to further fully explain the contents of the present invention to a person of ordinary skill, so as to make the disclosure of the present invention complete.

[0016] When an element is referred to in this specification as being "above" or "below" a different element, this includes all meanings whether the one element is directly "above" or "below" the different element or whether additional elements may intervene between these elements. In this specification, the terms "upper" or "lower" are relative concepts set from the perspective of an observer, and when the observer's perspective changes, "upper" may mean "lower" or "lower" may mean "upper".

[0017] On multiple drawings, the same reference numerals denote substantially identical elements. Also, terms such as "comprising" or "having" are intended to specify the presence of the described features, numbers, steps, operations, components, parts, or combinations thereof, and are not to be construed as precluding the presence or addition of one or more different features, numbers, steps, operations, components, parts, or combinations thereof.

[0018] In describing embodiments of the present invention, the terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intentions or conventions of users, operators, etc. Therefore, the definitions should be determined based on the overall content of the present invention.

[0019] In the present invention, in order to reduce the weight of the fender, the cord that was conventionally formed only of nylon fibers is changed to a material of aramid fiber, which is lighter in weight but excellent in strength, elasticity, and heat resistance than nylon fiber, and the thickness is reduced to achieve weight reduction.

[0020] Hereinafter, the medium and large-sized lightweight pneumatic fender of the present invention will be described in detail with reference to the drawings.

[0021] Referring to FIGS. 1 and 2, the size of the medium and large-sized lightweight pneumatic fender 100 according to the present invention satisfies the range where the diameter D is from 1,000 mm to 4,500 mm and the length L is from 1,500 mm to 12,000 mm, and may include an air filling portion 110, an inner rubber layer 120, a reinforcing layer 130, and an outer rubber layer 140.

[0022] The air-filled section 110 is an area filled with air, and it is desirable to maintain an internal pressure in the range of 50 kPa to 80 kPa so that it can cushion the impact between the pier and the ship when the ship docks or moors at the pier. For example, the internal pressure may be inversely proportional to the size of the fender 100. By providing the air-filled section 110, the impact absorption capacity is superior to that of conventional fenders, and it may be economical as no internal material is required.

[0023] The inner rubber layer 120 is provided so as to enclose the air-filled section 110 and may be made of an elastic material together with the outer rubber layer 140, which will be described below. The inner rubber layer 120 and the outer rubber layer 140 may be made of the same material, but they may be made of different materials depending on the application product or as necessary. For example, they may be made of one or more selected materials from polyethylene (PE), polypropylene (PP), rubber (Natural Rubber, NR), butadiene rubber (BR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), fluoro rubber, silicone rubber (VMQ), chloroprene rubber (CR), ethylene propylene diene rubber (EPDM), and butyl rubber (Isobutylene Isoprene Rubber, IIR).

[0024] In this embodiment, the thickness of the inner rubber layer 120, which is relatively less susceptible to impact from external pressure, may be 0.5 to 1 times the thickness of the outer rubber layer 140, and the color of the inner rubber layer 120 is not particularly limited, but may be black, for example.

[0025] On the other hand, the combined thickness of the inner rubber layer 120 and the outer rubber layer 140 may be 8 mm or less. As described above, optimizing the overlap of the inner rubber layer 120 and the outer rubber layer 140 can reduce not only weight and thickness but also costs. Furthermore, it can meet the maneuverability, speed, and strategic agility requirements of naval vessels.

[0026] The reinforcing layer 130 is provided on one surface of the inner rubber layer 120 and may be formed as at least one or more layers, and may include a first reinforcing layer 131 and a second reinforcing layer 132.

[0027] The first reinforcing layer 131 is laminated on one surface of the inner rubber layer 120 and may contain chafers, and may be formed of, for example, nylon fibers. In the present invention, nylon fibers may refer to polyamide-based synthetic polymer compounds. In Figure 2, the first reinforcing layer 131 is shown as a single layer, but it may be formed as one or more layers if necessary.

[0028] The second reinforcing layer 132 is laminated on top of the first reinforcing layer 131 and may include a cord. Conventionally, the cord was three to four times thicker than the chafer and made of nylon fiber, which resulted in a relatively heavy weight. In this embodiment, the cord material is replaced with aramid fiber, which is lighter in weight but has excellent strength, elasticity, and heat resistance compared to nylon fiber. Therefore, the performance of the conventional cord can be maintained while reducing its thickness, thereby achieving weight reduction. For example, the thickness of the cord, which was conventionally three to four times thicker than the chafer, was reduced to 1.5 to three times. That is, in this embodiment, the thickness of the second reinforcing layer 132 may be 1.5 to 3 times the thickness of the first reinforcing layer 131. In the present invention, the aramid fiber may be a fiber with high heat resistance, such that it does not burn even at 500°C. In Figure 2, the second reinforcing layer 132 is shown as a single layer, but it may be formed as one or more layers as necessary.

[0029] The outer rubber layer 140 is provided on one side of the reinforcing layer 130 and, being located on the outermost surface, is designed to easily absorb external impacts while being preferably thicker than the inner rubber layer 120 to reduce the risk of breakage. For example, the thickness of the outer rubber layer 140 may be one to two times the thickness of the inner rubber layer 120. If the thickness is outside the above range, it may be easily damaged by external impacts, and if damage occurs, it will be necessary to replace the entire medium-to-large lightweight pneumatic fender 100, which will not only be costly but may also make it difficult to achieve the weight reduction that is the main objective of this embodiment.

[0030] On the other hand, the outer rubber layer 140 may be gray so that it can be applied to vessels whose primary purpose is to conduct combat. The usable materials may include, for example, ethylene propylene diene rubber (EPDM), carbon black, processing oil, and gray pigment. The carbon black contained herein is present in trace amounts and does not affect the properties of the outer rubber layer 140, and can also prevent contamination of the hull during docking. When composed of the above-mentioned components, it has excellent oxidation resistance, ozone resistance, and corrosion resistance, so that medium- and large-sized lightweight pneumatic fenders 100 can be prevented from deteriorating when exposed to the seawater surface or damaged by natural factors such as salt, and can maintain their original color without significant change.

[0031] On the other hand, the medium-to-large lightweight pneumatic fender according to the present invention may be manufactured by the following steps, as shown in Figure 3: setting the spacing between the molding dies (S1); molding the inner rubber layer, reinforcing layer, and outer rubber layer using the molding dies (S2); joint molding the molded inner rubber layer, reinforcing layer, and outer rubber layer to manufacture the fender (S3); and inserting and assembling the fender into a vulcanizing die and vulcanizing it (S4).

[0032] For example, in the step of setting the spacing of the molding dies (S1), as shown in Figures 4 and 5, the spacing (gap) of the mandrels, which are the molding dies, may be set so that the distance G between the vulcanizing die 1 and the fender 100 is adjusted to an optimal range. The distance G between the vulcanizing die 1 and the fender 100 described above can be adjusted by changing the diameter of the molding die, and as the diameter of the molding die increases, the distance G between the vulcanizing die 1 and the fender 100 may decrease. Here, the distance G between the vulcanizing die 1 and the fender 100 refers to the distance G before vulcanization, which is before expansion occurs. In this embodiment, the thickness of the fender 100 is designed to be 11 mm or less, and the distance G before vulcanization may be 20% to 30% of the thickness of the fender 100. In this case, the expansion rate during vulcanization may be adjusted to 1% or less. If the interval G before vulcanization is adjusted to the range described above, the expansion rate during vulcanization in the vulcanization stage (S4), described below, will not exceed 1%, and the problem of air leakage can be resolved.

[0033] The present invention will be described in more detail below with reference to examples. These examples are solely for the purpose of illustrating the present invention in more detail, and it will be obvious to those who are ordinarily skilled in the art that the scope of the present invention is not limited thereto.

[0034] <Examples 1 to 4. Manufacturing of medium- and large-sized lightweight pneumatic fenders> As described above in Figures 4 and 5, the gap between the mandrels, which are the molding dies, was set so that the expansion rate during vulcanization would be adjusted to 1% or less. After that, the inner rubber layer, reinforcing layer, and outer rubber layer were molded and then separated from the mandrels. The inner rubber layer and reinforcing layer were then laminated and set so that the molded parts separated from the mandrels overlapped each other, and joint molding was performed. After inserting air to the extent that it maintained its shape, the outer rubber layer was molded to produce the fender. After inserting the fender into the vulcanization die and assembling it, air was filled into the inside of the fender through an air valve, and vulcanization was carried out to produce medium to large lightweight pneumatic fenders.

[0035] JPEG2026099743000002.jpg66170

[0036] <Comparative Examples 1 and 2: Manufacturing of lightweight pneumatic fenders for medium to large-sized vessels> Except for setting the gap between the mandrels, which are the molding dies, so that the expansion rate during vulcanization is adjusted to a range of 1% or more, medium to large-sized lightweight pneumatic fenders were manufactured using the same method as in Examples 1 to 4.

[0037] JPEG2026099743000003.jpg53170

[0038] (Experimental Example 1: Performance Test) The medium- and large-sized lightweight pneumatic fenders according to Example 1 and Example 2 were subjected to performance tests for air leakage and hydrostatic pressure according to the international standard ISO 17357-1:2014. The results are shown in Figures 6 and 7, and Tables 3 and 4.

[0039] Referring to Figure 6, in both Examples 1 and 2, it was confirmed that the morphology was good after air filling. Furthermore, as disclosed in Table 3, it was confirmed that the changes in diameter and length were within the acceptable range under the condition of an internal pressure of 80 kPa after air filling, and no air leakage was detected after observation for 30 minutes.

[0040] Referring to Table 4, in Examples 1 and 2, a hydrostatic pressure test was performed at a pressure of 250 kPa for 10 minutes, and it was confirmed that the change in length was within 10%, which is within the acceptable error range.

[0041] On the other hand, in the case of Comparative Example 1 and Comparative Example 2, as illustrated in Figure 7, air leakage occurred during the vulcanization process after air filling, making it impossible to proceed with further experiments.

[0042] JPEG2026099743000004.jpg107170

[0043] JPEG2026099743000005.jpg119170

[0044] As explained above, the specific description of the present invention has been given by examples with reference to the attached drawings. However, since the above-mentioned examples merely illustrate desirable examples of the present invention, the present invention should not be understood as being limited to the above examples. The scope of the present invention should be understood as the claims and equivalents described later.

[0045] For example, the drawings are schematic representations of each component to aid understanding, and the thickness, length, number, etc., of each component shown may differ from the actual dimensions due to the limitations of drawing creation. Furthermore, the material, shape, dimensions, etc., of each component shown in the above embodiment are merely examples and are not particularly limiting; various modifications are possible within a range that does not substantially exceed the effects of the present invention. [Explanation of symbols]

[0046] 1 Vulcanization mold 100 Medium to large lightweight pneumatic fenders, fenders 110 Air filling section 120 Inner rubber layer 130 Reinforcement layer 131 First Reinforcement Layer 132 Second Reinforcement Layer 140 Outer rubber layer

Claims

1. An air filling section where air is filled, An inner rubber layer is provided so as to enclose the air-filled section, A reinforcing layer is provided on one surface of the inner rubber layer, An outer rubber layer formed on one surface of the reinforcing layer, Includes, The reinforcing layer includes a first reinforcing layer and a second reinforcing layer laminated on the first reinforcing layer. The second reinforcing layer is made of aramid fibers. Medium to large-sized lightweight pneumatic fenders.

2. The thickness of the second reinforcing layer is 1.5 to 3 times the thickness of the first reinforcing layer. A medium-to-large lightweight pneumatic fender as described in claim 1.

3. The internal pressure of the air-filled section is between 50 kPa and 80 kPa. A medium-to-large lightweight pneumatic fender as described in claim 1.

4. The sum of the thicknesses of the inner rubber layer and the outer rubber layer is 8 mm or less. A medium-to-large lightweight pneumatic fender as described in claim 1.

5. The thickness of the inner rubber layer is 0.5 to 1 times the thickness of the outer rubber layer. A medium-to-large lightweight pneumatic fender as described in claim 1.

6. The size of the fender is such that the diameter is between 1,000 mm and 4,500 mm, and the length is between 1,500 mm and 12,000 mm. A medium-to-large lightweight pneumatic fender as described in claim 1.

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