JPH02289714A - Manufacture of pneumatic fender - Google Patents

Abstract

PURPOSE:To manufacture a fender in bilateral symmetric form by composing a duck for forming an inner bag of threads having different angles against the axis in a large diameter part and a small diameter part, and making the diameters equal in right and left when the internal pressure is applied into the inner bag. CONSTITUTION:A duck 14 to be the inner bag 1 is folded and fitted to the outer surface 3 of a mold 2 formed in semi-form of an inner bag 1, and the duck 14 is removed from the mold 2 after molding and volcanization to form the inner bag 1 having different diameters in right and left bordered in the central part. In this manufacture process, the duck 14 is made of multiple threads having different rigidity, and the angle of threads having the high rigidity of a large diameter part 6 side against the axial direction is made larger by the predetermined angle than the angle of threads having the high rigidity of a small diameter part 5 side against the axial direction. With this difference of the angles, the diameters of the right and left parts are expanded to the equal diameter in outline so as to be bilateral symmetric form when the internal pressure is applied into the inner bag 1. Next, an outer bag is covered for formation on the outer surface of the inner bag 1 under the condition that the air is pressed in the inner bag 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a pneumatic fender used as a shock absorber when a ship berths.

Generally speaking, when creating the cocoon-shaped inner bag 1 for pneumatic fenders, as shown in Figures 1 to 3, the shape corresponding to the half shape of the inner bag, that is, the shape of a cylindrical body, is A mold 2 having a substantially hemispherical tip is used (Fig. 1), and a rubber polymer 4 is attached to the outer peripheral surface 3 of the mold 2 by folding it back at the center and polymerizing the inner part 5 and the outer part 6 (Fig. 2). ), in this state, the polymer 4 is heated, molded and vulcanized, and then the polymer 4 is removed from the mold 2, the inner part 5 is pulled out from the polymerized state with the outer part 6, and this Inner bag 1 was made by enclosing air in polymer 4 (Figure 3). As is clear from the above manufacturing process, the inner bag 1 has a step 7 at the center folded part due to the difference in diameter between the inner and outer parts, and the outer part (the left part in Figure 3) 6 has a larger diameter inside the folded part. part(
The right portion) 5 is formed to have a small diameter.

Then, this inner bag 1 is pressurized, and the pressurized inner bag is used as a mold, and an inner rubber layer 8, a rubberized reinforcing cord layer 9, and an outer rubber layer 10 are sequentially wound around the outer peripheral surface of the inner bag, followed by molding and vulcanization. The outer bag 11 is made of the above-mentioned laminate. However, as mentioned above, the inner bag 1 has different diameters on the left and right sides with the center as a border, so if the outer bag 11 is formed in this state, the diameter of the left and right sides of the inner bag 1 will be different. The difference directly manifested itself in a difference in the diameter of the outer bag, and the finished fender was asymmetrical with different diameters on the left and right sides, posing a practical problem. Therefore, before making the outer bag 11, the inner part 5, which is the small diameter part, of the inner bag 1 is wrapped with a rubber material 18, etc., so that it has the same diameter as the outer part 6, which is the large diameter part, and the center The plan was to create a symmetrical shape with no steps. (Fig. 4) The above-mentioned technique called ``'' is generally used because the inner bag can be easily manufactured using a mold, but on the other hand, as mentioned above, the inner bag has a step in the center. It is inevitable that this will result in left-right asymmetry.

As mentioned above, in order to correct this left-right asymmetry of the inner bag, the conventional technology requires many materials and manufacturing processes, such as wrapping a rubber material around the small diameter part before wrapping the outer bag. Met.

The present invention overcomes the above-mentioned difficulties with such an inner bag having a step in the center, and can separate the small diameter part and the large diameter part by simply applying a predetermined air pressure without performing any processing on the inner bag before attaching the outer bag. The object of the present invention is to obtain an inner bag that expands so that its parts have approximately the same diameter.

In accordance with the above-mentioned object, the present invention includes folding and attaching a canvas serving as an inner bag to the outer circumferential surface of a mold formed into a substantially half shape of an inner bag,
After molding and vulcanization, the canvas is removed from the mold to create an inner bag with different diameters on the left and right sides with the center as a boundary, and air is pressurized into the cough inner bag to form an outer bag on the outside of the inner bag. In a method for manufacturing fenders, the canvas is composed of multiple types of yarns with different stiffness, and the angle of the more rigid yarn of the large-diameter side canvas with respect to the axial direction is set to the angle of the more rigid yarn of the small-diameter side canvas. A predetermined angle is larger than the angle of When a predetermined air pressure is applied to the inner bag, the angle with respect to the axial direction of the stiffer thread of the canvas is larger on the large diameter side than on the small diameter side, so the radius on the small diameter side increases due to the difference in stretch stiffness of the canvas. The extension in the direction is thicker than the extension on the large diameter side (both have approximately the same diameter).

haematuria Examples will be described with reference to the drawings.

In order to make the inner bag 1, a mold 2 in which the tip of a cylindrical body is formed into a hemispherical shape, which corresponds to the half shape of the inner bag, is used, which is the same as the prior art shown in FIG. 1.

In addition, a polymer 4 consisting of an inner part 5 and an outer part 6 is formed by folding at the center, and this polymer 4 is attached to the outer peripheral surface 3 of the mold 2, and in this state, it is heated, molded, and vulcanized. After that, the polymer 4 is removed from the mold 2, the inner portion 5 is pulled out from the polymerized state with the outer portion 6, and openings 12 are provided at both ends of the polymer 4 in the axial direction, and the openings 12 are opened. The method of making the inner bag 1 by attaching the cap 13 and sealing air into the polymer 4 through the cap 13 is also not particularly different from the conventional technique shown in FIGS. 1 to 3.

In this embodiment, in the above method, the polymer 4, that is, the canvas 14 constituting the cocoon-like inner bag 1, is made of rubberized fabric consisting of a highly rigid weft 15 and a low rigid warp 16 arranged perpendicularly thereto. The axial angles of the weft threads 15 and warp threads 16 are divided into the inner part (small diameter part) 5 and the outer part (large diameter part) 6.
The weft 15a of the inner part 5 is aligned with the axis 1 of the inner bag 1.
7, the warp threads 16a are arranged at right angles, and the weft threads 15b and warp threads 16b of the outer part 6 are arranged obliquely to the axis 17.

FIG. 5 shows the inner bag 1 when the canvas 14 is not stretched, and the inner bag 1 has a step 7 formed at a portion corresponding to the folded portion of the polymer 4, and an outer portion of the polymer 4 6. The left side portion corresponding to the inner portion 5 is formed to have a large diameter, and the right side portion corresponding to the inner portion 5 has a small diameter.

In this state, when pressurized air is filled into the inner bag 1 through the cap 13, the canvas 14 gradually expands and the inner bag l
expands, but the weft 15, warp 16,
In particular, since the angle of the highly rigid weft yarn 15 is different between the large diameter portion of the outer portion 6 and the small diameter portion of the inner portion 5 as described above, the degree to which the inner bag 1 expands in the direction perpendicular to its axis, that is, in the radial direction, is different. The difference is that the small diameter part expands more than the large diameter part, and when a predetermined internal pressure is applied, both parts 5 and 6 become approximately equal in diameter.
The step 7 is eliminated, and the outer surface of the inner bag 1 becomes flush with the road surface over its entire length (see FIG. 6).

To explain this point in detail, in Fig. 7, the canvas l4
The arrangement directions of the weft threads 15 and warp threads 16 are respectively the orthotropic main axis
, the direction cosine of the y-axis with respect to the X and Y axes is 1, respectively.
Let ra and -1, rtr. Here l・cosθ
, tm=sinθ.

When expressed as above, x of the canvas. When the relationship between the stress component in the y-axis direction and the stress components in the X and Y-axis directions is expressed in a matrix based on the equation of elastic mechanics, the following is obtained.

Or σX ... Tensile stress in the X-axis direction σy ... Tensile stress in the y-axis direction τxy ... Shear stress about the xy-axis σX ・
... Tensile stress in the X-axis direction σY ... Tensile stress in the Y-axis direction τXY ... Shear stress related to the xY-axis Similarly, the following relational expression exists between the strain components related to both the XY and xy coordinate axes of canvas. .

Or εX ... Longitudinal strain in the X-axis direction εy ... Longitudinal strain in the y-axis direction rxy ... Shear strain about the xy-axis εX ...
- Longitudinal strain in the X-axis direction εY ... Longitudinal strain in the Y-axis direction 7XY ... Shear strain about the XY axes Next, the relationship between strain and stress can be expressed as follows from the same equation regarding elastic mechanics for composite materials. be able to.

Here, CIJ''(1+J''X+LS) is a compliance coefficient expressed by the following equation.

... (6) EX ... Modulus of longitudinal elasticity of the canvas in the X-axis direction (modulus of longitudinal elasticity of the weft) EY ... Modulus of longitudinal elasticity of the canvas in the direction of the Y-axis (modulus of longitudinal elasticity of the warp) GXY ... Same Shear modulus of elasticity νX ... Boisson's ratio in the same X-axis direction νY ...
The elongation of the canvas in the radial direction when internal pressure is applied to the inner bag can be determined based on the Boasson's ratio in the same Y-axis direction and based on the equations (1) to (6).

Now, in this example, EX = 400 kg/cIl! By setting EY = 35 kg/cn GXY = 30 kg/cffl νX = νY = 0.49, and substituting these values into equation (6) and determining the canvas angle θ, the above Cij can be obtained, and the following Regarding the inner bag of this example, t (thickness) = 4 mm d (inner diameter on small diameter side) 600 mmP (internal pressure)
= 0.05 kg/afi, based on these values, the outer diameter D1 on the small diameter side is 6081, and the outer diameter D2 on the large diameter side is 6161. Note that τxy is O.

Therefore, the values of the above Cij and the above σX, σy are (5
), εX and εy can be obtained.

As a result of calculation, under the above conditions, the above εy is θ
0.0419 when is 0 degrees, 0.0 when θ is 45 degrees
255, so the above DI+ Di after expansion is D+ = (1 + 0.0419) X608''=
633mmD= = (1 + 0.0255)
616' = 632mm, so the weft of the canvas on the small diameter side is parallel to the axis of the inner bag, and the weft of the canvas on the large diameter side is parallel to the axis.
By arranging them at an angle of 5 degrees, both the small diameter part and the large diameter part can be expanded to approximately the same diameter. It goes without saying that the angle for making the diameters the same varies depending on the various factors mentioned above.

The outer bag is wrapped around the outer periphery of the inner bag manufactured in this manner in the same manner as in the prior art described above to produce a fender.

As explained above, the canvas constituting the inner bag has different angles with respect to its axis in the large diameter part and the small diameter part, and the angle on the large diameter part side of the thread with higher rigidity is the same as that in the small diameter part. Since the angle is set a certain amount larger than the side angle, when internal pressure is applied to the inner bag, the canvas on the large diameter side and the small diameter side can both expand to approximately the same diameter, eliminating the step in the center. The entire outer circumferential surface of the inner bag is flush, and there is no need to perform any processing to make the inner bag symmetrical before attaching the outer bag.

Therefore, the number of materials and manufacturing steps is small, and the pneumatic fender can be easily manufactured.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing the process of manufacturing the inner bag, Figure 4 is a front view of a conventional fender manufactured by the above process, and Figure 5 is a front view of the inner bag according to the present invention. , FIG. 6 is a front view of the inner bag after inflation, and FIG. 7 is an explanatory view of the inclined canvas of the inner bag. DESCRIPTION OF SYMBOLS 1... Inner bag, 2... Mold, 3... Mold outer peripheral surface, 4... Polymer, 5... Inner part, 6... Outer part, 7... Step, 8... ...Inner rubber layer, 9...
Rubberized reinforcing cord layer, 10... Outer rubber layer, 11.
...outer bag, 12...opening, 13...cap fitting, 14
...Canvas, 15...Weft, 16...Warp, 17.
...Axis line, 18...Rubber material.

Claims (1)

[Claims] The canvas that will become the inner bag is folded and attached to the outer circumferential surface of a mold formed into a roughly half-shaped inner bag, and after molding and vulcanization, the canvas is removed from the mold to form an inner bag with different diameters on the left and right sides of the center. In the manufacturing method of pneumatic fender material, the canvas is made of multiple types of yarns with different stiffness, and the large diameter part is The angle with respect to the axial direction of the more rigid thread of the side canvas is set to be a predetermined angle larger than the angle of the more rigid thread of the small diameter side canvas, and when internal pressure is applied to the inner bag due to the difference in angle, the left and right portions 1. A method for manufacturing a pneumatic fender, characterized in that the diameters of the fenders are expanded to approximately the same diameter so that the fenders are symmetrical.