JPH02202439A - Production of float for lane rope of swimming pool - Google Patents

Abstract

PURPOSE:To obtain the above rope which is free from generation of a sharp break surface and a fragment and has proper softness and an excellent wave attenuation function by spirally cutting a cylindrical solid lightweight material which consists of an expanded material having rubber or plastic composition and a closed cell structure and has a through-hole in the center and forming a wave attenuating groove. CONSTITUTION:A cylindrical solid lightweight material 1 is spirally cut which consists of an expanded material having rubber or plastic composition of proper softness, a closed cell structure and has a through-hole in the center. For example, while the cylindrical solid lightweight material 1 is rotated, a cutter blade 4 is pushed thereon and moved to the axial direction of the material 1 to cut it. Thereby the spiral cross- sectional face is easily formed. When an axial pipe 2 made of plastic having proper softness is preferably inserted into the central through-hole and the cylindrical solid lightweight material is elongated at proper length along the axial pipe and fixed, the spiral wave attenuating grooves having the prescribed intervals are formed in accordance with the spiral cut face. The spiral width can be freely controlled by changing both the speed for moving the cutter blade and the speed for rotating the cylindrical solid lightweight material. Further, the width of the wave attenuating groove can be freely controlled by changing the elongated length.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a float for a swimming pool course rope.

[Conventional technology]

Floats for swimming pool course ropes have the necessary buoyancy, have the function of damping waves generated during competitive swimming, and,
It should be colored as clearly as possible, so that the position of the swimmer can be easily recognized.

Taking these points into consideration, various changes have been made, and now floats made of hollow molded objects made of brightly colored plastic (mainly polyethylene composition) are used for collection, As a good damping function, for example, as shown in Fig. 5, Flow 1-a (Design Registration No. 485
No. 581), or as shown in Figure 6, large hollow floats (f) with a plurality of protrusions (l) and small hollow floats (g) are arranged alternately on the shaft pipe through which the lobes pass, and wave-dissipating grooves are formed. A series of float body units e having a shape j are constructed, and these are used singly or in combination with a lobe inserted into an axial tube.

[Problem to be solved by the invention]

Floats made of hollow molded plastic as mentioned above become brittle and deteriorate over time, and are easily damaged by shocks caused by contact with swimmers' hands and feet. , a serious flaw has been pointed out in that it breaks into pieces, often injuring swimmers.

Therefore, in order to prevent the float from breaking, making the hollow molded product thicker and more robust increases the cost, increases the weight, makes it difficult to maintain buoyancy, and becomes hard, making it difficult for swimmers to hold their hands. The pain is even greater when the feet make contact, and the swimmer's pain remains unresolved.

On the other hand, if attempts are made to prevent damage from contact with swimmers' hands and feet by reducing the wall thickness or making the product flexible and hollow, the mechanical strength will decrease, making it more likely to tear and having poor durability. Additionally, there are problems in that it is easily deformed and its wave damping function is degraded.

In order to eliminate the occurrence of sharp fracture surfaces and fragments in hollow molded products, it is necessary to use solid (filled) lightweight materials (e.g. closed-cell foams such as rubber and plastics).
If a material with appropriate flexibility is selected, fracture surfaces and fragments will not be sharp, and the impact will be reduced even if a swimmer's hands or feet come into contact with it, making it possible to provide a suitable float material. It becomes possible. However, it is difficult to manufacture products with a complex shape that has effective wave-absorbing protrusions and wave-absorbing grooves in order to satisfy the above-mentioned wave damping function using solid lightweight materials, and the product shape becomes irregular. There is also the problem that the cost is high.

Therefore, an object of the present invention is to provide a simple float for a safe swimming pool course rope that does not generate sharp fracture surfaces or fragments even when broken, has appropriate flexibility, and has an excellent wave damping function. The purpose is to provide a method that can be manufactured using a processing method.

[Means to solve the problem]

According to the present invention, in order to achieve the above object, a cylindrical solid lightweight material made of a closed-cell foam of rubber or plastic composition and having a central through hole is cut into a spiral shape. There is provided a method for manufacturing a float for a course rope, which comprises stretching and fixing the float to an appropriate length to form a spiral wave-absorbing groove.

Further, according to the present invention, a cylindrical solid lightweight material made of a closed-cell foam of rubber or plastic composition and having a central through hole is cut by two cutter blades set at a predetermined interval. A method for manufacturing a float for a course rope is provided, which comprises cutting the float into a spiral shape to obtain two floats each having a continuous spiral wave-dissipating groove.

[Operation and effect of the invention]

According to the first method of the present invention, a cylindrical solid body is made of a closed-cell foam of rubber or plastic composition with appropriate flexibility obtained by a conventional method, and has a through hole in the center. Cutting lightweight materials into spiral shapes. For example, while rotating the solid lightweight material, a cutter blade is pressed against it and moved in the axial direction of the cylindrical solid lightweight material to cut it. Then, a spiral cut surface is easily formed. Therefore, by inserting a shaft tube preferably made of plastic having appropriate flexibility into the central through hole, and extending and fixing the cylindrical solid lightweight material to an appropriate length along this shaft tube, the spiral Spiral wave-absorbing grooves are formed at predetermined intervals corresponding to the cut surface. The width of the spiral portion 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-dissipating groove can be adjusted by changing the length of the wave-dissipating groove.

On the other hand, according to the second method of the present invention, a 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 spacing between the two cutter blades, two floats are obtained in which continuous spiral wave-absorbing grooves are already formed.

The width 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. Moreover, if the width of the formed wave-absorbing groove is too wide, it is possible to compress it in the axial direction, contrary to the first method, to narrow the interval between the spiral portions (width of the wave-absorbing groove).

In this way, a safe float for a swimming pool course rope having a wave damping function can be manufactured by an extremely simple method of spiral cutting. The float for a course rope obtained by the method of the present invention has a spiral wave-dissipating groove as described above, so it has an excellent wave damping function, and the material is made of rubber or plastic composition with appropriate flexibility. Since it is made of foam with a closed cell structure, it does not cause much pain even when a swimmer's hands or feet come into contact with it.
Moreover, even if it breaks, it is safe because no sharp fracture surfaces or fragments are generated, and furthermore, it has extremely significant effects and advantages in that it can significantly reduce costs.

The solid lightweight material that can be used in the present invention is a cylindrical foam with a closed cell structure and a through hole in the center made of rubber or plastic that has flexibility and buoyancy suitable for a float for a course rope. Any molded foamed product of olefinic resin such as polyethylene or ethylene-vinyl acetate copolymer (EVA) can be used, but preferred are
Alternatively, a long pipe-shaped foamed product can be cut into an appropriate length and then used to cut into a spiral shape.

〔Example〕

The present invention will be specifically described below with reference to Examples.

Example I EVA (vinyl acetate content 15%) 100 @Setting part Zinc stearate 2.0 l' dicumyl peroxide (40%) 2. Ol'Azodicarbonamide 3.01 The above composition is kneaded with a heated roll, charged into a two-part mold with a cylindrical cavity provided with a core rod in the center, and cross-linked and foamed under pressure and heat to form a mixture in the center. A foam with through holes was obtained.

Next, as shown in Fig. 1, a suitable shaft 2 is inserted into the central through hole of this foam 1, and both ends of the shaft 2 are supported by supports 3, 3 provided with bearings such as bearings, and rotated. While pressing the appropriate cutter blade 4 at a certain distance from the end of the foam 1, cut until it reaches the shaft, and while moving the cutter blade in the axial direction of the shaft 2 (in the direction of the arrow), It was cut to a certain distance from the other end to obtain a cylindrical float with a spiral cut surface.

Thereafter, as shown in FIG. 3, a synthetic resin shaft tube 6 of an appropriate length is inserted into the central through hole of the foam, stretched to an appropriate length, and both ends are glued with adhesive or the like. A coarse rope float 5 having a spiral wave-dissipating wave t+"lj 8 was obtained by fixing it with a terminal 7 or the like as shown in FIG.

When the obtained float was used as a course rope in a swimming pool, it was confirmed that the float was safe even when swimmers came into contact with it and had an extremely excellent wave damping effect.

Example 2 Same as Example 1 above, except that the cylindrical foam 1 produced in Example 1 above was cut using two cutter blades set at a predetermined interval as shown in FIG. Two floats each having a spiral wave-absorbing groove formed therein were obtained by cutting the float into a spiral shape using the method described above.

A synthetic resin shaft tube of an appropriate length is inserted into the center through-hole of this float, and a disk-shaped foam body with through-holes is inserted into both ends, and terminals etc. are inserted using adhesive. A float for a course rope having a spiral wave-dissipating groove similar to that shown in FIG. 3 and having excellent safety and wave damping effect was obtained.

[Brief explanation of the drawing]

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

Claims (2)

[Claims] (1) A cylindrical solid lightweight material made of a closed-cell foam of rubber or plastic composition and having a central through hole is cut into a spiral shape, and then stretched to an appropriate length.
A method of manufacturing a float for a course rope, characterized in that it is fixed to form a spiral wave-dissipating groove. (2) A cylindrical solid lightweight material made of closed-cell foam of rubber or plastic composition and having a central through hole is cut into a spiral shape using two cutter blades set at a predetermined interval. A method for producing a float for a course rope, characterized in that two floats each having a continuous spiral wave-dissipating groove are obtained.