JPS6220020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a float suitable for use, for example, in holding ropes for seaweed cultivation at the sea surface.

For example, when cultivating seaweed, seeds are often sandwiched between strands of a rope 1 and held by spherical floats 2 at regular intervals, as shown in FIG. In this case, as the seaweed grows, its weight increases, causing the horizontal position of the rope 1 and the float 2 itself to sink. Therefore, initially a small float is attached to the rope, and as the seaweed grows, it is replaced with a float with greater buoyancy. Work is required.

However, frequent replacement of the float poses a problem in terms of workability, and the state of growth must be constantly monitored. On the other hand, if the float 2 is not replaced during the growth process, the float 2 will sink below the sea surface and burst due to water pressure, creating the risk that the cultured seafood will be washed away and cause serious damage.

In view of this, the main purpose of the present invention is to propose a method for manufacturing a float that hardly ruptures at a practical depth due to the water pressure applied when the float sinks due to the gravity applied toward the bottom of the water. shall be.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view showing an example of a float for implementing the present invention. First, using a female mold of a desired size, the main body 3a and the rope locking portion 3b are integrally formed into a hollow body shape by blow molding or the like. This material is preferably polyethylene material or ABS resin. Next, a plug sealing hole 3c for filling the inside of the float 3 with compressed air is bored through the center of the locking part 3b. This hole 3c may be provided during integral molding. The cross section of the plug sealing hole 3c is formed in a tapered shape with a larger diameter on the outside and a smaller diameter on the inside because the plug is press-fitted from the outside. The taper angle should be determined by considering the material of the stopper, etc.
Taper angles of 10~20° can be selected.

Next, compressed air of 1 to 3 kg/cm ² is injected into the float 3 using the plug sealing hole 3c, and immediately after the injection is completed, a taper plug 5 made of the same material as the float is inserted.
Press-fit with a rotational force of more than 10,000 revolutions per second. At this time, the contact surface between the taper plug 5 and the plug sealing hole 3c reaches a high temperature of around 300° C. due to frictional heat and melts. When the welding surfaces of both are completely welded, the rotation of the taper plug 5 is stopped, and while the taper 5 is kept pressed toward the float side, cold water is sprayed onto the welded plug 5 to rapidly cool it. The plug 5 is brought into close contact with the float 3 sufficiently. In this case, since it is undeniable that some internal pressure will drop when injecting the taper plug 5, a higher pressure is injected in advance in consideration of leakage. Further, the film thickness of the float 3 is also set in consideration of the internal pressure.

As shown in FIG. 3, the taper stopper 5 is provided with a cross-shaped protrusion 5a on the rear end side so as to be able to engage with the chuck of a high-speed rotating machine. In addition, in order to increase the welding area, as shown in FIG. 4, a large-diameter flange 5b is provided on the rear end side of the plug 5, and an annular projection 5c with a sharp cross section is formed on the float contact side of the flange 5b. As a result, when the plug 5 rotates at high speed, the flange portion 5b and the annular projection 5c are welded together with the tapered surface. In this case, since the diameter of the flange portion 5b is larger than that of the tapered portion, more frictional heat is generated, which has the effect of further ensuring the degree of adhesion between the two.

FIG. 5 is a diagram showing the depth durability of a float manufactured by the method of the present invention and a conventional float manufactured by a conventional method without applying pressure.
Bar line A shows the depth durability of a float with an internal pressure of 1 kg/cm ² made by the method of the present invention, but since the depth of the experimental water area is 30 m, a pressure of 4 atmospheres or more will be applied to the float when it is lowered to the bottom. However, there will be no flat tire. Bar line B shows the depth durability of the float without applying internal pressure, but it punctures at about 15 meters. A puncture is a phenomenon in which the float surface becomes dented due to high external pressure. Furthermore, in the case of other materials, the durability is found to be extremely low as shown in bars C and D.

As described above, according to the present invention, the float main body and the rope locking part are integrally molded with a female mold, a plug sealing hole is provided, and compressed air is injected into the float through the plug sealing hole, and at the same time, compressed air is injected into the float. Since the stopper was press-fitted and welded using high-speed rotational force, the float obtained by the method of the present invention has greater water depth durability compared to ordinary floats, and the float can be used for example in aquaculture equipment. If installed, the float will not be punctured even if the float sinks due to the growth of aquaculture or due to natural disasters such as typhoons and tsunamis, so if the heavy object is slightly released,
Since it floats on the water surface, it can prevent artificial aquaculture equipment from collapsing. If a puncture occurs due to the float sinking, a great deal of work is required to raise it to the surface of the water, but this has the effect of making such work unnecessary.

Further, according to the present invention, a flange is provided at the rear end of the plug, and the tip is tapered, so that when the plug rotates at high speed, frictional heat between the flange and the float surface that comes into contact with the plug is large in diameter. This generates a large amount of heat, thereby ensuring reliable thermal welding of the two.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the state in which the float is used, Fig. 2 is a sectional view showing an example of a float used for carrying out the present invention, Fig. 3 is a perspective view showing an example of a taper stopper, and Fig. 4 is a diagram showing another example of the float. FIG. 5 is a cross-sectional view showing an example, and is a diagram showing the depth durability of a float manufactured by the method of the present invention and a conventional float manufactured by a conventional method without applying pressure. 3... Float, 3a... Main body, 3b... Rope locking part, 3c... Plug sealing hole, 5... Taper plug,
5b...flange, 5c...annular projection.

Claims (1)

[Scope of Claims] 1. The float main body and the rope locking part are integrally molded with a female mold, a plug sealing hole is provided, and compressed air is injected into the float through the plug sealing hole, and at the same time, the plug is inserted into the plug sealing hole at high speed. A method for manufacturing a float, characterized in that it is press-fitted and welded using rotational force. 2. The method of manufacturing a float according to claim 1, wherein a flange is provided at the rear end of the plug, and the tip is tapered.