JP2000005345A - Volleyball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball of soft touch, which does not give a pain, while having the merit of a thread-wound reinforced volleyball. SOLUTION: This volleyball consists of a rubber tube 1 of a spherical hollow body to be filled with compressed air, a thread-wound reinforced layer 2 obtained by uniformly winding filament thread on the surface of the tube 1, a closed-cell sponge layer 3 on the layer 2 and a leather 4 stuck to the layer 3. In this case, at the time of molding the layer 3, closed-cell sponge is intruded into the layer 2 to integrate the layer 3 and the layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in shock absorption and rebound performance of a volleyball used in a volleyball game.

[0002]

2. Description of the Related Art Conventionally, volleyball has been wound or reinforced on the surface of a rubber tube having a spherical hollow body for enclosing compressed air, and then an intermediate rubber sheet is vulcanized and formed thereon, and a skin is bonded thereto. There are two types of balls called "sticked balls" and a ball called "sewed balls" in which a plurality of panels are sewn and covered on the surface of a rubber tube. In addition, a "sticking ball" of thread reinforcement reinforced with excellent durability is used. As shown in FIG. 3, a typical thread-wound reinforcement “sticking ball” has a structure in which 50 D (denier) to 100 D
A thread-wound reinforcing layer 2 formed by uniformly winding a nylon or polyester yarn of D was formed, and an unvulcanized rubber sheet 6 such as natural rubber or polybutadiene rubber was stuck on the reinforcing layer 2 and vulcanized. Natural leather 4 or artificial leather 4 is bonded to the surface of a rubber sheet 6. As an example of the above-mentioned "sticking ball" of thread winding reinforcement, Japanese Patent Publication No. 58-3193
No. 4 describes the invention.

[0003]

The above-mentioned "pasted ball" of the wound reinforcement is excellent in spherical stability and durability, but when the unvulcanized rubber sheet is vulcanized and molded, the wound reinforcement layer is compressed and hardened. In addition, the rubber sheet has a hard laminated structure, the ball has a hard touch, and the impact on the player's hands, arms, shoulders, and the like is large. Although the rubber sheet is used to obtain elasticity and flexibility, it cannot be thickened by the weight regulation of the competition rules and is as thin as 0.4 to 0.6 mm. Had become a ball. Therefore, there has been a demand for the development of a volleyball which has the advantage of reinforcement of a pincushion, has a soft touch and does not hurt.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a spherical hollow rubber tube filled with compressed air, a wound reinforcement layer in which a filament yarn is uniformly wound around the surface of the rubber tube, and a wound reinforcement layer. Closed foam sponge layer on top,
In the volleyball in which leather is adhered to the independent foam sponge layer, at the time of forming the independent foam sponge layer, the independent foam sponge penetrates into the thread reinforcing layer, so that the independent foam sponge layer and the thread reinforcing layer are integrated, This is to solve the above-mentioned problem.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A tube is formed into a spherical hollow body with rubber having low air permeability such as butyl rubber. Nylon or polyester filament yarn, which is slightly thinner than the conventional one, is uniformly wound around the surface of the rubber tube to form a wound reinforcement layer. An unvulcanized rubber sheet that becomes an independent foamed sponge during vulcanization of a mold is laminated on the thread-wound reinforcing layer, and is heated and vulcanized in the mold to form an independent foamed sponge layer. At this time, the independent foamed sponge also flows into the thread-wound reinforcement layer below the rubber sheet, and the independent foamed sponge layer and the thread-wound reinforcement layer are integrated. Therefore, the thread-wound reinforcement layer can have flexibility without being compression-hardened. A rubber-based adhesive is applied to the surface of the mold-formed independent foam sponge layer, and natural leather or artificial leather is bonded to form a volleyball.

[0006]

An embodiment of a volleyball according to the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway side view of a volleyball of the present invention, and FIG. 2 is a sectional view of a main part of the present invention. The volleyball according to the present invention is obtained by molding a butyl rubber tube 1 into a spherical hollow body, injecting compressed air into the tube 1 and, as shown in FIG. Then, 15 to 23 g of a 40D nylon filament yarn having an increased elongation under a low load is uniformly wound to form a wound reinforcement layer 2. An unvulcanized rubber sheet having a thickness of 0.55 to 0.65 mm was adhered to the surface of the thread-wound reinforcement layer 2 according to the formulation shown in Table 1, and a shallow groove matching the leather pattern on the volleyball surface was formed on the inner surface. Into a mold (not shown) having a temperature of 145
~ 155 ° C, time 4 ~ 6 minutes, 5.5 in tube 1
Compressed air of 6.5 kg / cm ² is injected to perform mold vulcanization.

[0007]

[Table 1]

[0008] By performing the mold vulcanization as described above, the rubber sheet becomes an independent foamed sponge, the independent foamed sponge flows into the thread reinforcing layer 2, and the independent foamed sponge layer 3 and the thread reinforcing layer 2 are integrated. Be transformed into

The independent foamed sponge layer 3 taken out of the mold
On the surface, the leather pattern of the volleyball surface is exposed. According to the pattern, a natural leather 4 is adhered to the surface of the independent foamed sponge layer 3 with an adhesive 5 made of a natural rubber or chloroprene rubber to form a volleyball.

[0010]

In the volleyball according to the present invention, the rubber sheet forms a closed foam sponge layer by mold vulcanization, and the closed foam sponge flows into the wound reinforcing layer, and the closed foam sponge layer and the wound reinforcing layer are formed. Are integrated,
The pincushion reinforcement layer can be made more elastic and softer than the conventional rubber sheet alone without compression hardening.

[0011] Accordingly, it is possible to obtain a ball bearing having advantages of ball stability and durability, which are advantages of reinforcement of a thread winding, and also have a greater impact absorption and repulsion than conventional ones. An example of the effect is shown in the impact force measurement diagram of FIG. 4 and the rebound height measurement diagram of FIG. FIG. 4 shows a change in impact force when the ball is naturally dropped from a height of 2 m onto a force plate and the air pressure of the ball is changed to 0.3 to 0.4 kg / cm ^2. Volleyball according to
It is 10 to 15% smaller than the conventional product. FIG.
The rebound height was measured by dropping naturally under the same conditions as the impact force measurement, and the volleyball according to the present invention was 13 to 15 cm larger than the conventional product. As described above, according to the present invention, a volleyball with a soft touch, less pain, and good momentum than conventional products can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a volleyball of the present invention.

FIG. 2 is a sectional view of a main part of the present invention.

FIG. 3 is a sectional view of a main part of a conventional product.

FIG. 4 is an impact force measurement diagram.

FIG. 5 is a rebound height measurement diagram.

FIG. 6 is a curve diagram showing load-elongation of a nylon yarn.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tube 2 Pincushion reinforcement layer 3 Independent foaming sponge layer 4 Leather 5 Adhesive 6 Rubber sheet

Claims (1)

[Claims] 1. A rubber tube (1) of a spherical hollow body for enclosing compressed air, a spool reinforcing layer (2) in which a filament yarn is uniformly wound around the surface of the rubber tube (1), and a spool reinforcing layer (2). 2) On top of the closed foam sponge layer (3),
In the volleyball in which leather is stuck to the independent foamed sponge layer (3), when the independent foamed sponge layer (3) is formed, the independent foamed sponge penetrates into the thread-wound reinforcing layer (2), and the independent foamed sponge layer (3) A volleyball characterized by integrating a wound reinforcement layer (2).