JPH0643109B2 - Method for manufacturing floats for swimming pool course ropes - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a float for a course rope of a swimming pool.

[Conventional technology]

The float for the course rope of the swimming pool has the necessary buoyancy, has the function of attenuating the waves that occur during swimming, and
It should be as clearly and color-coded as possible so that the swimmer's swimming position is easily recognizable.

In consideration of these points, after undergoing various changes, currently, floats made of hollow plastic molded products (mainly polyethylene-based composition) that are lightly colored are generally used. For example, as shown in FIG. 5, for example, a float a (design registration No. 485581) in which a lattice-shaped wave-dissipating protrusion d is provided on the surface of a hollow cylindrical body b having a shaft tube body c.
No.) or as shown in FIG. 6, a large hollow float f in which a plurality of ridges i are provided on the surface of a shaft tube h through which a rope is passed.
And a small hollow float g are alternately arranged to form a series of float body units e in which the wave-dissipating groove portion j is formed, and these are used alone or in combination, and a rope is inserted through the shaft tube.

[Problems to be Solved by the Invention]

The float made by hollow molding of plastics as described above is fragile and deteriorated over time, and is easily damaged by the impact of contact of the swimmer's hands and feet. Particularly, the broken hollow molded product has a sharp fracture surface. It has been pointed out that there are serious flaws in that it breaks into pieces and often damages swimmers.

Therefore, in order to prevent damage to the float, thickening the hollow molded product to make it robust will increase the cost, and it will be difficult to maintain buoyancy due to the increase in weight, and it will become harder, so the swimmer's hand, The pain is exacerbated when the feet come into contact and the swimmer's distress remains irreversible.

On the other hand, when attempting to prevent damage due to the contact of the swimmer's hands and feet by reducing the wall thickness or making it into a flexible hollow molded product, the mechanical strength decreases, it is easy to tear, and the durability is poor. At the same time, there is a problem that it is easily deformed and the wave attenuation function is deteriorated.

In order to eliminate the generation of sharp fractured surfaces and debris in such hollow molded products, use a solid (filled) lightweight material (for example, foam with a closed cell structure such as rubber or plastics).
By selecting a material with appropriate flexibility, the fracture surface and fragments will not be sharp, and even if the swimmer's hands and feet come into contact, the impact can be reduced, and a suitable float material can be provided. It will be possible. However, it is difficult to manufacture a complicated shape product provided with an effective wave-dissipating protrusion or wave-dissipating groove in order to satisfy the above-mentioned wave attenuation function with a solid lightweight material, and the product shape also becomes uneven, There is a problem that the cost becomes high.

Therefore, an object of the present invention is to provide a safe swimming pool course rope float that does not generate sharp fractured surfaces or debris even if it breaks, has appropriate flexibility, and has an excellent wave damping function. It is to provide a method that can be manufactured by a processing method.

[Means for Solving the Problems]

According to the present invention, in order to achieve the above object, a cylindrical solid lightweight material having a closed cell structure of a rubber or plastics composition and having a central through hole is spirally cut, A method for manufacturing a float for a course rope is provided, which is characterized in that the spiral wave-dissipating groove is formed by extending and fixing it to an appropriate length later.

Further according to the present invention, a cylindrical solid lightweight material having a closed cell structure foam of rubber or plastics composition, and having a central through hole, by two cutter blades set at a predetermined interval. There is provided a method for manufacturing a float for a course rope, characterized by obtaining two floats that are spirally cut to form continuous spiral wave-dissipating grooves.

[Operation and Effect of the Invention] According to the first method of the present invention, it is made of a foam having a closed cell structure of rubber or plastics composition and having appropriate flexibility, which is obtained by a usual method, and has a through-hole at the center. A cylindrical solid lightweight material having is cut into a spiral shape. For example, while rotating the solid lightweight material, a cutter blade is pressed against the solid lightweight material to move it in the axial direction of the cylindrical solid lightweight material for cutting. Then, a spiral cut surface is easily formed. Therefore, preferably, a plastic shaft tube having appropriate flexibility is inserted into the central through hole, and the cylindrical solid lightweight material is stretched and fixed along the shaft tube to an appropriate length to fix the spiral thread. Spiral wave-dissipating grooves are formed at predetermined intervals corresponding to the cut surface. The width of the spiral part of the float can be freely adjusted by changing the speed at which the cutter blade is moved and the rotation speed of the cylindrical solid lightweight material, and the width of the wave-breaking groove by changing the length of extension.

On the other hand, according to the second method of the present invention, the cylindrical solid lightweight material is cut in the same manner as the first method except that two cutter blades set at a predetermined interval are used. Then,
Depending on the set distance between the two cutter blades, two floats having continuous spiral wave-dissipating grooves already formed can be obtained.
The widths of the spiral portion and the wave-dissipating groove can be freely adjusted by adjusting the set interval between the two cutter blades, the speed at which the cutter blades are moved, and the rotational speed of the cylindrical solid lightweight material. Further, when the width of the formed wave-breaking groove is too wide, it is possible to reduce the interval between the spiral portions (width of the wave-breaking groove) by compressing in the axial direction contrary to the first method.

In this way, a safe swimming pool course rope float with a wave damping function can be manufactured by a very simple method of spiral cutting. Since the float for course rope obtained by the method of the present invention has the wave-breaking groove in the spiral shape as described above, it has an excellent wave damping function, and its material is made of rubber or plastics composition having appropriate flexibility. Since it is made of foam with a closed cell structure, there is not much pain when the swimmer's hands and feet touch
Moreover, even if it breaks, no sharp fractured surface or fragments are generated, so it is safe, and the cost can be greatly reduced.

As the solid lightweight material that can be used in the present invention, a cylindrical foam or the like having a through-hole in the center with a closed cell structure of rubber or plastics composition having appropriate flexibility and buoyancy for a course rope float is used. All of them can be used, but preferably, a foamed product of an olefin resin such as polyethylene or ethylene-vinyl acetate copolymer (EVA),
Alternatively, a long pipe-shaped foamed product can be cut into an appropriate length and used to cut into a spiral shape.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 EVA (vinyl acetate content 15%) 100 parts by weight Zinc stearate 2.0 〃 Dicumyl peroxide (40%) 2.0 〃 Azodicarbonamide 3.0 〃 The above composition was kneaded with a heating roll, and a core rod was placed at the center. It was charged in a two-divided mold having a cylindrical cavity provided and crosslinked and foamed under pressure and heating to obtain a foam having a through hole in the center.

Then, as shown in FIG. 1, an appropriate shaft 2 is inserted through the center through hole of the foam body 1, and both ends of the shaft 2 are supported by columns 3 provided with bearings such as bearings for rotation. While pressing, a suitable cutter blade 4 is pressed at a position at a constant distance from the end of the foam 1 and cut until it reaches the shaft, and the cutter blade 4 is moved in the axial direction of the shaft 2 (arrow direction) while moving the foam 1. It cut | disconnected to the position of a fixed distance from the other end, and obtained the cylindrical float which has a spiral cut surface.

After that, as shown in FIG. 3, a synthetic resin shaft tube 6 having an appropriate length is inserted into the center through hole of the foamed body and stretched to an appropriate length. The coarse rope float 5 having the spiral wave-dissipating groove 8 was obtained by fixing the terminal 7 as shown in FIG.

When the obtained float was used as a course rope for a swimming pool, it was confirmed that the float is safe even if it comes into contact with a swimmer and has an extremely excellent wave damping effect.

Example 2 The same as Example 1 above, except that the cylindrical foam 1 produced in Example 1 above was cut using two cutter blades set at predetermined intervals as shown in FIG. Two floats having spiral wave-dissipating grooves were obtained by spirally cutting by the method described in 1.

Insert a synthetic resin shaft tube of an appropriate length into the center through hole of this float, and further insert a disk-shaped foam body that also has through holes at both ends, using terminals such as terminals using adhesive. A float for a course rope, which was fixed and had a spiral wave-dissipating groove similar to that shown in FIG. 3 and which was excellent in both safety and wave damping effect, was obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a specific mode for carrying out the first method of the present invention, and FIG. 2 is a schematic configuration diagram showing an example of a specific mode for carrying out the second method of the present invention, FIG. 3 is a perspective view showing an example of a float for a course rope obtained by the method of the present invention, FIG. 4 is a partial cross-sectional view of the end thereof, and FIG.
FIG. 6 and FIG. 6 are partial sectional perspective views of a conventional course rope float. 1 is a cylindrical foam, 2 is a shaft, 3 is a strut, 4 is a cutter blade, 5 is a course rope float, 6 is a shaft tube, 7 is a terminal, and 8 is a spiral wave breaking groove.

Claims (2)

[Claims] 1. A cylindrical solid lightweight material having a closed cell structure of rubber or plastics composition and having a central through hole is spirally cut, and then stretched to an appropriate length. A method for manufacturing a float for course rope, which comprises fixing and forming a spiral wave-dissipating groove. 2. A cylindrical solid lightweight material having a closed cell structure of rubber or plastics composition and having a central through hole is spirally formed by two cutter blades set at predetermined intervals. A method for producing a float for a course rope, which comprises cutting into two pieces to obtain two floats each having a continuous spiral wave-dissipating groove formed therein.