JP2006291628A - Pneumatic type fender - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic type fender improved in durability against a local bending strain generated when folded. <P>SOLUTION: Rigidity of the pneumatic type fender is increased by newly laminating a protection cord layer 6 and a protection rubber layer 7 on a bag body 2 constituted by inserting a reinforcing layer 4 between an inner layer rubber 3 and an outer layer rubber 5, a radius ρ1 of curvature when folded becomes larger than in the conventional structure, the local bending strain in the reinforcing layer 4 is eased, at the same time, a position of a neutral surface NL is moved to the outside from the center of the thickness of the reinforcing layer 4 to shorten a distance Y3 between the neutral surface NL and a boundary plane of the outside of the reinforcing layer 4, and the tensile strain is further eased. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic fender, and more particularly to a pneumatic fender capable of improving durability by relieving local bending strain generated during folding.

  As the pneumatic fender, as shown in FIG. 6, an overall outline of the state in which air is sealed inside, and as shown in FIG. 7 in an enlarged cross-sectional structure, the reinforcing layer 4 is interposed between the inner rubber 3 and the outer rubber 5. There is known a bag body 2 that is configured by inserting a base 2 and a base portion 8 that can enclose air inside (see, for example, Patent Document 1).

  The inner layer rubber 3 is made of rubber having excellent airtightness in order to hold the air enclosed inside, and the outer layer rubber 5 is made of rubber that is resistant to abrasion and weather resistance and is not easily affected by seawater. ing. In addition, the reinforcing layer 4 is configured by arranging steel cords, organic fiber cords, and the like, and functions as a pressure-resistant material that can withstand internal pressure during normal deformation and compression deformation at the time of ship berthing.

  When such a pneumatic fender 1 is stored or transported, it may be folded without enclosing air inside due to problems such as space.

However, in the folded state, local bending strain is generated in the bag body 2, so that there is a problem that the strength of the reinforcing layer 4 is reduced and the outer layer rubber 5 is wrinkled, thereby reducing durability. This problem becomes more serious when the folded state lasts for a long time or when folding is repeated. In particular, if the size is increased and the outer diameter W1 of the cylindrical portion 2b shown in FIG. 6 exceeds a predetermined value, specifically, more than 2.5 m, it cannot be transported by land due to legal regulations unless it is folded and made smaller. Therefore, improvement in durability against local bending strain caused by folding has been demanded.
JP 200221044 A

  An object of the present invention is to provide a pneumatic fender capable of relieving local bending strain generated during folding and improving durability.

  In order to achieve the above object, a pneumatic fender according to the present invention includes a bag configured by inserting a reinforcing layer between an inner layer rubber and an outer layer rubber, and a base capable of enclosing air inside the bag body. In the pneumatic fender having a portion, at least one protective cord layer is laminated on the outer surface of the outer rubber layer, and a protective rubber layer is laminated on the outer surface of the protective cord layer. is there.

  According to the pneumatic fender of the present invention, it is provided with a bag configured by inserting a reinforcing layer between the inner layer rubber and the outer layer rubber, and a cap part capable of enclosing air inside the bag body. By providing at least one protective cord layer laminated on the outer surface of the outer rubber layer and a protective rubber layer laminated on the outer surface of the protective cord layer on the air-proof fender, the rigidity against local bending is increased. The local bending strain generated in the reinforcing layer during folding can be alleviated. Accordingly, it is possible to improve the durability by preventing the strength of the reinforcing layer that functions as a pressure-resistant material of the pneumatic fender from being lowered.

  In addition, since the bag can be folded while preventing the strength of the reinforcing layer from being lowered, even a large fender can be easily transported by land.

    Furthermore, since the newly laminated protective cord layer and protective rubber layer protect the internal structure such as the reinforcing layer from damage and abrasion from the outside, durability can be improved.

  Hereinafter, a pneumatic fender according to the present invention will be described based on the embodiments shown in the drawings. The overall shape of the pneumatic fender 1 is the same as that shown in FIG. 6 and has a hollow cylindrical shape, but the bag 2 has a cross-sectional structure illustrated in FIG.

  As shown in FIG. 1, the bag 2 has a protective cord layer laminated on the outer surface of the outer rubber 5 in contrast to the conventional structure in which the reinforcing layer 4 is interposed between the inner rubber 3 and the outer rubber 5. 6 and a protective rubber layer 7 laminated on the outer surface of the protective cord layer 6.

  The protective cord layer 6 is configured by arranging steel cords, organic fiber cords, and the like, and at least one layer is laminated. The protective cord layer 6 can also have the same specifications as the reinforcing layer 4. Since the protective rubber layer 7 is laminated on the outermost periphery of the bag body 2, rubber that is resistant to abrasion and weather resistance and seawater is adopted, and the same specifications as the outer layer rubber 5 can be adopted.

  When the pneumatic fender 1 is folded for storage or transportation, first, as illustrated in FIG. 2, first, the circular end portions 2a are arranged on both sides or one side of the circular end portions 2a. The inside air is sucked out from the base 8 and flattened. Next, as illustrated in FIG. 3, the cylindrical portions 2b on both sides in the longitudinal direction are folded inward to make the width dimension W2 equal to or less than a predetermined width.

  Here, since the bag body 2 has a structure in which the protective cord layer 6 and the protective rubber layer 7 are added to the conventional structure shown in FIG. 7, the rigidity against folding is high, and the local portion generated in part A in FIG. Flexural strain can be reduced.

  FIG. 4 shows the state of local bending strain generated in part A of FIG. 3, and FIG. 5 shows the state of local bending strain when the bag 2 having the conventional structure shown in FIG. Show.

  As shown in FIG. 5, in the conventional structure, by folding the bag body 2, the center of the thickness of the reinforcing layer 4 becomes the neutral surface NL, for example, bent at a radius of curvature ρ2, and the reinforcing layer 4 has a neutral surface. Maximum compressive strain and tensile strain occur at the inner and outer boundary surfaces at a distance Y1 from NL, respectively.

  On the other hand, as shown in FIG. 4, the bag body 2 of the pneumatic fender 1 according to the present invention has high rigidity due to the newly laminated protective cord layer 6 and protective rubber layer 7. The radius ρ1 is larger than the curvature radius ρ2 in the case of the conventional structure, and the local bending strain in the reinforcing layer 4 can be reduced.

  In addition to this, the position of the neutral surface NL moves outside the center of the thickness of the reinforcing layer 4, and the distance Y3 between the neutral surface NL and the outer boundary surface of the reinforcing layer 4 is the distance shown in FIG. It becomes smaller than Y1, and the tensile strain is further relaxed. The maximum strain in the reinforcing layer 4 is the inner boundary surface located at a distance Y2 from the neutral plane NL, and here is compressive strain. Since the cords constituting the reinforcing layer 4 are embedded in rubber, it is considered that the actual strain is greatly relieved particularly on the compression side.

  Thus, according to the present invention, compared to the conventional structure, the local bending strain generated in the reinforcing layer 4 when the bag body 2 is folded can be alleviated, and the pressure-resistant material of the pneumatic fender 1 As a result, it is possible to improve the durability by preventing the strength of the reinforcing layer 4 functioning as a drop in strength.

  Therefore, as shown in FIG. 6, even if the outer diameter W1 of the cylindrical portion 2b of the bag body 2 is larger than 2.5 m in a state where air is sealed inside, the internal air is By discharging and folding at least one location, the width dimension W2 can be reduced to 2.5m or less without causing excessive bending strain, and it can be easily landed on a truck without legal restrictions. It can be transported. Note that when the bag body 2 is folded, the air inside the bag body 2 may be discharged to such an extent that it can be folded without completely discharging the air. In addition, durability is improved for long-term storage in a folded state and repeated folding, and handling becomes easy.

  25% of the total thickness T2 of the protective cord layer 6 and the protective rubber layer 7 that are additionally laminated with respect to the total thickness T1 of the bag 2 having the conventional structure constituted by the inner layer rubber 3, the reinforcing layer 4, and the outer layer rubber 5. By setting it to 80% or less, the local bending strain generated in the reinforcing layer 4 can be relaxed and the durability can be improved while suppressing a significant increase in rigidity and an increase in weight.

  In addition, by making the thickness T4 of the protective cord layer 6 15% or more and 65% or less of the thickness T3 of the reinforcing layer 4, the movement of the reinforcing layer 4 is moderately suppressed and the durability is further improved. Is possible.

  The newly laminated protective cord layer 6 and protective rubber layer 7 protect the internal structure such as the reinforcing layer 4 from external damage and wear, so that the durability is improved in this respect as well.

  In the embodiment, the bag body 2 has a hollow cylindrical shape, but is not limited to this, and other hollow shapes can be adopted.

  With the five-layer structure as shown in FIG. 1, the local bending strain generated in the reinforcing layer when the bag body (example) of the pneumatic fender having the specifications shown in Table 1 is bent under predetermined conditions was estimated. Thus, the influence on the reinforcing layer by folding the bag was confirmed. For comparison, the three-layer bag (comparative example) shown in FIG. 7 was also estimated. The difference between the example and the comparative example is only the presence or absence of the protective cord layer and the protective rubber layer, and other specifications are common. The calculated bending strains at the inner and outer boundary surfaces of the reinforcing layer are shown in Table 1.

  In the case of bending at the same predetermined bending stress, the bending strain is calculated in the examples and comparative examples of this structure, assuming that the curvature radius ρ as shown in Table 1 is obtained by experience, due to the difference in rigidity. is doing.

  The neutral surface position in Table 1 indicates the distance between the assumed neutral surface NL and the inner boundary surface of the reinforcing layer, and a negative value in the inner boundary surface strain indicates that it is a compressive strain. .

  From this result, when the bag was folded, it was confirmed that the example can relieve the local bending strain generated in the reinforcing layer more than the comparative example, and the durability can be improved by preventing the strength of the reinforcing layer from being lowered. .

It is sectional drawing which illustrates the structure of the bag body of the pneumatic fender of this invention. It is explanatory drawing which illustrates the 1st process of folding a pneumatic fender. It is explanatory drawing which illustrates the 2nd process of folding a pneumatic fender. It is sectional drawing which illustrates the local bending distortion which arises in the pneumatic fender of this invention when it folds. It is sectional drawing which illustrates the local bending distortion which arises in the conventional pneumatic fender when it folds. It is a front view which illustrates the whole general form of a pneumatic fender which enclosed air inside. It is sectional drawing which illustrates the structure of the bag body of the conventional pneumatic fender.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic fender 2 Bag body 2a Circular end 2b Tube part 3 Inner layer rubber 4 Reinforcement layer 5 Outer layer rubber 6 Protection cord layer 7 Protection rubber layer 8 Base part

Claims (5)

  In a pneumatic fender comprising a bag body configured by inserting a reinforcing layer between an inner layer rubber and an outer layer rubber, and a base part capable of enclosing air inside the bag body, the outer layer rubber A pneumatic fender characterized by laminating at least one protective cord layer on the outer surface and a protective rubber layer on the outer surface of the protective cord layer.   The pneumatic fender according to claim 1, wherein the total thickness of the protective cord layer and the protective rubber layer is 25% or more and 80% or less of the total thickness of the bag body. The pneumatic fender according to claim 2, wherein the thickness of the protective cord layer is 15% or more and 65% or less of the thickness of the reinforcing layer.   The bag body which laminated | stacked the said protection cord layer and the protection rubber layer is a hollow cylinder shape, and the outer diameter of the cylinder part in the state which enclosed air inside exceeds 2.5 m. Pneumatic fender.   5. The pneumatic fender according to claim 4, wherein the width dimension in a state where at least one portion is folded by discharging air from the inside of the bag body in which the protective cord layer and the protective rubber layer are laminated is 2.5 m or less. Wood.

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