Patent Publication Number: US-2005143205-A1

Title: Softball with great resilient coefficient

Description:
FIELD OF INVENTION  
      The present invention relates softballs for softball gaming, and more particularly to a softball that is easy to make and can sustain substantially constant hardness against variations in temperature and humidity and has a great resilient coefficient. Further, by adjusting the ratio of thickness of the core and the inner cover, the softball can attain a higher coefficient of resilience as required.  
     DESCRIPTION OF THE PRIOR ART  
      As shown in  FIG. 1 , a softball of a conventional inner structure includes a core  10  and a cover  20  surrounding the core  10 . The core is made by a mold and of a cork-type or a silk-cotton-type material. A softball thus made has the disadvantage of having non-uniform hardness over the ball surface. To remedy this fault, a core shell  30  formed by winding yarn strings around the core is applied first. The core  10  and the core shell  30  are then surrounded by the cover  20  to form a softball. The addition of a core cover  30  complicates the manufacturing process, and it also reduces the coefficient of resilience, leading to a less bouncing softball.  
      As shown in  FIG. 2 , a softball of another conventional inner structure includes a core  40  and a cover  50  surrounding the core  40 . The core  40  is made by a mold and of a polyurethane-type material. Because of the polyurethane-type material, the softball is of uniform hardness and higher coefficient of resilience. Further, the structural simplicity, without a string-wound core shell, makes it is easy to make. However, since the polyurethane-type material is susceptible to variations in temperature and humidity, the hardness of the softball is not constant over a variety of environments.  
     SUMMARY OF THE INVENTION  
      Accordingly, the present invention provides a softball having a novel inner structure which is easy to make and can sustain substantially constant hardness against variations in temperature and humidity. Further, by adjusting the ratio of thickness of the core and the inner cover, the softball can meet a required coefficient of resilience.  
      To achieve the above objectives, a softball according to the present invention comprises a core, an inner cover and an outer cover. The core is made by a mold and of either a cork-type material or a polyurethane-type material. The inner cover surrounds said core, being made of a material different from the core and selected from the group of a cork-type material and a polyurethane-type material. The outer cover surrounds both the core and the inner cover. The softball thus formed can sustain substantially constant hardness against variations in temperature and humidity. Further, by adjusting the ratio of thickness of the core and the inner cover, the softball can meet a required coefficient of resilience. 
    
    
     DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a cross-sectional view of a softball of a conventional inner structure.  
       FIG. 2  is a cross-sectional view of a softball of another conventional inner structure.  
       FIG. 3  is a cross-sectional view of the first preferred embodiment of the present invention as a softball.  
       FIG. 4  is a cross-sectional view of the second preferred embodiment of the present invention as a softball. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The various objects and advantages of the present invention will be more readily understood from the following detailed description of preferred embodiments, when read in conjunction with the appended drawings.  
      As shown in  FIG. 3 , the first preferred embodiment of the present invention as a softball comprises a core  60 , an inner cover  80  and an outer cover  70 . The core  60  is of substantially spherical shape and is made of a predetermined cork-type material. Further, the core  60  is made by a mold. The inner cover  80  surrounds the core  60 , and the inner cover  80  is made of a predetermined polyurethane-type material. The outer cover  70  surrounds the core  60  and the inner cover  70  to form a softball. The core  60  can also be made of a silk-cotton material instead.  
      As shown in  FIG. 4 , the second preferred embodiment of the present invention as a softball comprises a core  60 , an inner cover  80  and an outer cover  70 . The core  60  is of substantially spherical shape and is made of a predetermined polyurethane-type material. Further, the core  60  is made by a mold. The inner cover  80  surrounds the core  60 , and the inner cover  80  is made of a predetermined cork-type material. The outer cover  70  surrounds the core  60  and the inner cover  70  to form a softball. The inner cover  80  can also be made of a silk-cotton material instead.  
      As indicated by the aforecited preferred embodiments, a softball according to the present invention is characterized by a core  60  surrounded by an inner cover  80 . The core  60  and the inner cover  80  are respectively made of a cork-type material and a polyurethane material or vice versa. Although those materials are common internal materials of conventional softballs, the combination of those two types of materials makes possible a softball that is easy to make and can sustain substantially constant hardness against variations in temperature and humidity. Further, by adjusting the ratio of thickness of the core and the inner cover, the softball can attain a higher coefficient of resilience as required.  
      The present invention is thus described, and it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.