Hollow Plastic Ball

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a ball and, more particularly, to a hollow plastic ball.

2. Description of the Related Art

A conventional hollow plastic ball comprises two semi-spherical shells combined together. Each of the two semi-spherical shells has a surface provided with a plurality of holes and has an inner circumferential face provided with a connecting rib. The connecting ribs of the two semi-spherical shells are melted and connected during the molding process so that the two semi-spherical shells are combined together. When the hollow plastic ball is thrown, it will rotate during flight. However, the connecting ribs of the two semi-spherical shells decrease the weight balance of the hollow plastic ball, so that the hollow plastic ball will sway freely due to a deflection of the center of gravity and cannot be maintained stably along a determined movement trace, thereby causing inconvenience to the user in manipulation of the hollow plastic ball. In addition, the hollow plastic ball only has the connecting ribs of the two semi-spherical shells so that the hollow plastic ball has an uneven structural strength and will be deformed due to hitting or treading.

BRIEF SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a hollow plastic ball that keeps a balance of flight and has an enhanced structural strength.

In accordance with the present invention, there is provided a hollow plastic ball comprising two semi-spherical shells arranged symmetrically and combined together. Each of the two semi-spherical shells has a surface provided with a plurality of holes. Each of the two semi-spherical shells has an inner circumferential face provided with a horizontal rib and a semi-circular vertical rib. The horizontal rib of each of the two semi-spherical shells has an annular shape. The vertical rib of each of the two semi-spherical shells has a cruciform arcuate arrangement. The horizontal rib of each of the two semi-spherical shells is formed by residual plastic material of each of the two semi-spherical shells. The horizontal ribs of the two semi-spherical shells are combined integrally.

Preferably, the two semi-spherical shells are molded integrally by ultrasonic welding.

Alternatively, the two semi-spherical shells are molded integrally by a bonding agent.

According to the primary advantage of the present invention, each of the two semi-spherical shells is provided with the horizontal rib and the semi-circular vertical rib to enhance the stability of the hollow plastic ball, so that when the hollow plastic ball is thrown out, the hollow plastic ball keeps a weight balance during flight and will not move or sway freely due to a deflection of the center of gravity, such that the hollow plastic ball can be maintained stably along a smooth movement trace, thereby facilitating the user manipulating the hollow plastic ball.

According to another advantage of the present invention, the horizontal rib and the vertical rib of each of the two semi-spherical shells reinforce the structural strength of the hollow plastic ball to prevent the hollow plastic ball from being deformed or distorted due to hitting or treading.

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a partially perspective cross-sectional view of a hollow plastic ball in accordance with the preferred embodiment of the present invention.

FIG. 2 is an exploded perspective view of the hollow plastic ball as shown in FIG. 1.

FIG. 3 is a perspective view of a semi-spherical shell of the hollow plastic ball in accordance with the preferred embodiment of the present invention.

FIG. 4 is a cross-sectional view of the hollow plastic ball as shown in FIG. 1.

FIG. 5 is a cross-sectional view of the hollow plastic ball taken along line D-D as shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-5, a hollow plastic ball in accordance with the preferred embodiment of the present invention comprises two semi-spherical shells 10 arranged symmetrically and combined together. Each of the two semi-spherical shells 10 has a surface provided with a plurality of holes 11. Each of the two semi-spherical shells 10 has an inner circumferential face provided with a horizontal rib 12 and a semi-circular vertical rib 13. The horizontal rib 12 of each of the two semi-spherical shells 10 has an annular shape and presents an angle of 360 degrees. The vertical rib 13 of each of the two semi-spherical shells 10 has a cruciform arcuate arrangement and presents an angle of 180 degrees.

In fabrication, each of the two semi-spherical shells 10 is initially provided with the holes 11 and the semi-circular vertical rib 13. Then, the two semi-spherical shells 10 abut each other and are welded. Then, the two semi-spherical shells 10 are pressed by a pressing die to form the horizontal rib 12 on each of the two semi-spherical shells 10, so that the horizontal ribs 12 of the two semi-spherical shells 10 are heated and combined integrally. Then, the two semi-spherical shells 10 are cooled so that the two semi-spherical shells 10 are molded into the hollow plastic ball. In such a manner, the horizontal rib 12 of each of the two semi-spherical shells 10 is formed by residual plastic material of each of the two semi-spherical shells 10 during the molding process.

In the preferred embodiment of the present invention, the two semi-spherical shells 10 are molded integrally by heating connection. Alternatively, the two semi-spherical shells 10 are molded integrally by ultrasonic welding. Alternatively, the two semi-spherical shells 10 are molded integrally by a bonding agent.

Accordingly, each of the two semi-spherical shells 10 is provided with the horizontal rib 12 and the semi-circular vertical rib 13 to enhance the stability of the hollow plastic ball, so that when the hollow plastic ball is thrown out, the hollow plastic ball keeps a weight balance during flight and will not move or sway freely due to a deflection of the center of gravity, such that the hollow plastic ball can be maintained stably along a smooth movement trace, thereby facilitating the user manipulating the hollow plastic ball. In addition, the horizontal rib 12 and the vertical rib 13 of each of the two semi-spherical shells 10 reinforce the structural strength of the hollow plastic ball to prevent the hollow plastic ball from being deformed or distorted due to hitting or treading.

Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.