CORE OF BALL FOR BASEBALL

PURPOSE: To lessen the large burden on a pitcher, i.e., the burden to the action to apply rotation to a ball by setting the radius of an inside core and the thickness of an outer layer core to nearly halve of the radius of a core body and setting the sp. gr. of this inside core to about two-fold the sp. gr. of this outer layer core and eventually specifying the inertia moment of the ball. CONSTITUTION: This regulation baseball ball is constituted by providing the circumference the core body 10 deposited with the outer layer core 12 on the outer side of the inside core 11 existing at the center with a fine thread winding layer 13 and a shell layer 14 of the uppermost layer similar to known balls. The inside core 11 existing at the center is molded of a mixture composed of synthetic resins 11a and weight adjusting fine pieces 11b to a spherical shape. The radius thereof corresponds nearly to half the radius of the core body 10. The outer layer core 12 on the outer side of the inside core 11 is molded of a mixture composed of the synthetic resins and cork grains and the thickness thereof is nearly equal to the radius of the inside core 11. The sp. gr. of the inside core 11 is set at about two-fold the sp. gr. of the outer layer core 12. As an eventual result thereof, the ball to be finally produced is so set that its inertial moment eventually attains 0.75 to 0.80G/cm and more preferably about 0.76 to 0.78G/cm .