JP2001069873A - Float and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a float having a large strength by strongly integrating both ends of a net through pipe and a hollow body through fusing without generating molding deficiency and spoiling mold strength in a blow molding. SOLUTION: This float 1 has a hollow body 2 made of a thermoplastic resin as a float main body. Net through pipes 3 passing through the hollow body 2 are inserted during a blow molding as a different body. During the blow molding, the both ends of the net through pipes 3 and the hollow body 2 are mutually fused. The fused parts 4 form step-formed compressed parts 5 which spread toward the longitudinal direction of the net through pipes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a float having a hollow body made of a thermoplastic resin as a float body and a method for producing the float.

[0002]

2. Description of the Related Art Floating signs on sea and lake surfaces, partition nets and safety nets stretched underwater, fishing nets set underwater, etc. can be attached with floats and used as signs on the water surface, or float on the water surface. Holding is done. And
The float for this purpose has a structure in which hooks are provided on a hollow body of the float and a rope is connected to the float, or a rope insertion portion is formed integrally with the float body to allow the rope to pass therethrough.

A technique for blow molding a hollow cylindrical body having a core tube penetrating the center thereof is described in Japanese Patent Publication No. 44-25913. In order to form two parisons, the molding equipment must be large and the molding process is complicated. In addition, since the core tube is blow-molded integrally with the main body, particularly large molded products are required. It has been known that molding failure occurs and molding strength is impaired.

[0004]

SUMMARY OF THE INVENTION Therefore, a technical object of the present invention is to provide a float having a hollow body made of a thermoplastic resin as a float body, wherein a rope insertion tube penetrating the hollow body is provided as a separate body. Inserting at the time of blow molding, the two ends of the rope insertion tube body and the hollow body are welded to each other in the blow molding, and the welded portion forms a compressed portion that extends in the longitudinal direction of the rope insertion tube body, so that a large float is formed. Even in this case, it is possible to obtain a high-strength float in which both ends of the rope insertion tube body and the hollow body are welded and integrated firmly without causing molding failure or loss of molding strength in blow molding. With the goal.

[0005]

In order to achieve the above object, the present invention provides a float having the structure described in claims 1 to 4, and a method for manufacturing a float described in claims 5 to 7. That is, the float according to claim 1 is a float having a hollow body obtained by blow-molding a thermoplastic resin as a float main body, and having a rope insertion pipe penetrating the hollow body, and both ends of the rope insertion pipe. The portion and the hollow body are welded to each other, and the welded portion forms a compressed portion that extends in the longitudinal direction of the rope insertion tube body.

[0006] A float according to a second aspect is characterized in that, in the configuration of the first aspect, the rope insertion tube body has a smoothly enlarged diameter at both ends in the opening direction.

A float according to claim 3 is characterized in that, in the structure of claim 1 or 2, the compression portion of the rope insertion tube with the hollow body extending in the longitudinal direction has a stepped shape. is there.

[0008] The float according to claim 4 is the float according to claims 1 and 2.
Alternatively, in the configuration described in 3, the foamed resin is filled in the hollow body.

According to a fifth aspect of the present invention, there is provided a float blow molding method in which a hollow body of a thermoplastic resin is used as a float body, wherein a rope insertion pipe is inserted into a parison disposed between open split molds. Insert and hold the body through the insert holding member, then close the split mold and blow the pressurized fluid into the parison to blow mold the hollow body that will be the float body, and insert both ends of the inserted rope insertion tube body. The hollow body and the hollow body are compression-welded to each other, and a compression portion extending in the longitudinal direction of the rope insertion tube body is formed at the welded portion.

According to a sixth aspect of the present invention, there is provided the float manufacturing method according to the fifth aspect, wherein the rope insertion pipe body has a smooth enlarged diameter at both ends in the opening direction, and the rope insertion pipe body is inserted and held. The insert holding member has a base side forming a diameter expansion holding portion corresponding to one diameter expansion shape of the rope insertion pipe body, and a diameter expansion holding corresponding to the other diameter expansion shape of the rope insertion pipe body at the tip side. The auxiliary member forming the part is detachably attached.

According to a seventh aspect of the present invention, in the method of the fifth or sixth aspect, a hole is formed in the hollow body and the foamed resin is filled.

[0012]

FIG. 1 is an overall perspective view showing an example of a float according to the present invention, FIG. 2 is a sectional view taken along line XX of FIG. 1, and FIG. 3 is a blow of the float shown in FIG. FIG. 4 is a cross-sectional view showing a state before the mold is closed, showing a molding state, FIG. 4 is a cross-sectional view showing a state immediately after the mold is closed and the pressurized fluid is introduced into the parison from the state of FIG. 3, and FIG. It is an expanded sectional view of the part in circle Y.

1 and 2, reference numeral 1 denotes a float. The float 1 has a substantially spherical hollow body 2 obtained by blow molding a thermoplastic resin as a float body.
A rope insertion pipe 3 passing through the center of the hollow body 2 forming the float body penetrates, and one end of the rope insertion pipe 3 and the hollow body 2 are welded to each other. The welded portion 4 forms a compressed portion 5 that extends in the longitudinal direction of the rope insertion tube body 3, and in the illustrated embodiment, the compressed portion 5 has a stepped shape. The rope insertion tube body 3 has both ends in a smoothly enlarged shape in the opening direction, and the portion is hereinafter referred to as a tulip portion 6. The portion of the hollow body 2 connected to the compression portion 5 is a flat portion 7 to improve the welding strength between the rope insertion tube 3 and the hollow body 2 in the compression portion 5. The other end of the rope insertion tube 3 has the same configuration as that of the one end except for the configuration of the one end, and a description thereof will be omitted.

A foamed resin (not shown) is provided inside the hollow body 2.
FIG. 2 shows a filling hole 8 of the foamed resin. As shown, the filling hole 8 of the foamed resin is sealed after filling the foamed resin.

The float 1 according to the present invention is made of a rigid material such as high-density polyethylene resin, polypropylene resin, polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polystyrene resin, ABS resin, polycarbonate resin, modified polyphenylene oxide resin, etc. It is preferable to use an excellent blow-moldable thermoplastic resin.

The rope insertion tube 3 is a molded product separate from the hollow body 2. The constituent material may be the same or different from the hollow body 2, but the same material is suitable for improving the welding strength between the rope insertion tube body 3 and the hollow body 2. . To further improve the welding strength,
It is preferable to heat both ends of the rope insertion tube 3 to be inserted. Foamed resin is made of polyethylene resin, polypropylene resin, ethylene vinyl acetate copolymer resin, acrylic resin, polychlorinated resin which is foamed by mixing of inert gas (gas mixing method), blowing agent decomposition method, solvent diffusion method, chemical reaction, etc. Examples include vinyl resin, polystyrene resin, ABS resin, polyurethane resin, nylon resin, phenol resin, and urea resin.

The float according to the present invention shown in FIGS. 1 and 2 is blow-molded in the manner shown in FIGS. That is, as shown in FIG.
The parison 11 is extruded from the head 10 and arranged between them, and the rope insertion tube 3 is inserted into the parison 11 from below and inserted between the split molds 9 and 9. Tube insertion tube 3
Is a separate body formed separately from the hollow body 2 which is blow-molded as described above.
And the insert holding member 12 has a base portion side forming a large-diameter holding portion 13 corresponding to one tulip portion 6 of the rope insertion tube 3 and a tip end thereof. On the side, an auxiliary member 14 that forms a large-diameter holding portion corresponding to the other tulip portion 6 of the rope insertion tube 3
Is attached and detached. Insert holding member 12
When the rope insertion tube 3 is inserted into the cable, the auxiliary member 14 is removed, the rope insertion tube 3 is inserted, and then the auxiliary member 14 is attached again.

Next, as shown in FIGS. 4 and 5, the split molds 9, 9 are closed, a pressurized fluid (air) is introduced into the parison 11, and the hollow body 2 is blow-molded. Further, the parison 11 is compressed by the rope insertion tube 3 between the pinch-off portions of the split molds 9 and 9 and the insert holding member 12 by closing the mold, and the compression portion 5 is formed to form the hollow body 2 and the rope insertion tube. Body 3
And are sealed. In the illustrated embodiment, the compression portion 5 has a stepped shape, but the pinch-off portions of the split dies 9, 9 are also formed into the shape. Reference numeral 15 denotes a burr section.

When the hollow body 2 is to be filled with a foamed resin, the foamed resin is filled by opening a filling hole 8 after blow molding, and the filled hole 8 is sealed after the filling.

In the float 1 according to the present invention, both ends of the rope insertion pipe 3 and the hollow body 2 are welded to each other, and the welded portion 4 is a compression section that extends in the longitudinal direction of the rope insertion pipe 3. 5, even if the rope insertion pipe 3 is separate from the hollow body 2, the strength is such that both ends of the rope insertion pipe 3 and the hollow body 2 are welded and integrated tough. A large float 1 can be obtained. In addition, the rope insertion pipe 3 is
Since the both ends form the tulip portion 6, the rope can be easily inserted, and a intensive load is not applied to the binding portion of the rope (not shown) connected to the float 1, thereby preventing the break of the rope. It is useful.

According to the manufacturing method of the present invention, the hollow body 2
Since the rope insertion pipe body 3 penetrating through is inserted as a separate body at the time of blow molding, it is only necessary to form the substantially spherical monotonous hollow body 2 by blow molding, and even if the float 1 is large, Also, molding can be easily and efficiently performed without causing molding defects.

[0022]

According to the present invention, there is provided a float having a hollow body made of a thermoplastic resin as a float main body, wherein a rope insertion tube body penetrating the hollow body is provided as a separate body and is inserted at the time of blow molding, and blow molding is performed. Both ends of the rope insertion pipe body and the hollow body are welded to each other, and the welded portion forms a compressed portion that extends in the longitudinal direction of the rope insertion pipe body, so that even a large float can be used for blow molding. Without molding failure or loss of molding strength,
In addition, it is possible to obtain a high-strength float in which both ends of the rope insertion tube body and the hollow body are welded and integrated tough.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an example of a float according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 shows a blow molding mode of the float shown in FIG. 1,
It is sectional drawing which shows the state before a mold closure.

FIG. 4 is a cross-sectional view showing a state immediately after closing the mold from the embodiment of FIG. 3 and introducing a pressurized fluid into a parison.

FIG. 5 is an enlarged cross-sectional view of a portion inside a wavy circle Y in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Float 2 Hollow body 3 Rope insertion pipe 4 Welding part 5 Compression part 6 Tulip part 7 Flat part 8 Filling hole 9, 9 Split mold 10 Head 11 Parison 12 Insert holding member 13 Large diameter holding part 14 Auxiliary member 15 Burr part

Claims (7)

[Claims] 1. A float having a hollow body formed by blow-molding a thermoplastic resin and having a float main body, the float having a rope insertion pipe penetrating the hollow body, and both ends of the rope insertion pipe and a hollow body. Are welded to each other, and the welded portion forms a compressed portion that extends in the longitudinal direction of the rope insertion tube body. 2. The rope insertion pipe body according to claim 1, wherein both ends thereof have a smoothly enlarged shape in the opening direction.
The float described. 3. The float according to claim 1, wherein a compression portion of the rope insertion tube body and the hollow body extending in the longitudinal direction has a stepped shape. 4. The float according to claim 1, wherein the hollow body is filled with a foamed resin. 5. A method for blow molding a float using a thermoplastic resin hollow body as a float body, wherein a rope insertion tube is inserted into and held by an insert holding member in a parison disposed between open split molds. Then, the split mold is closed, and the pressurized fluid is blown into the parison to blow-mold the hollow body serving as the float body, and both ends of the inserted rope insertion tube body and the hollow body are compression-welded to each other. Forming a compressed portion extending in the longitudinal direction of the rope insertion tube at the welded portion. 6. The rope insertion pipe body has both ends formed in a smoothly enlarged shape in the opening direction, and the insert holding member for inserting and holding the rope insertion pipe body has one side of the rope insertion pipe body at the base side. It is characterized in that it has a configuration in which a large-diameter holding portion corresponding to the large-diameter shape is formed, and an auxiliary member that forms the large-diameter holding portion corresponding to the other large-diameter shape of the rope insertion tube body is attached to and detached from the distal end side. The method for producing a float according to claim 5. 7. The method for producing a float according to claim 5, wherein a hole is formed in the hollow body and the foamed resin is filled.