Patent Publication Number: US-2017354850-A1

Title: Hollow Plastic Ball

Description:
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.