Baseball

摘要

A baseball suitable for continuous use in a pitching machine comprises a molded, resilient polyurethane foam sphere having a type A-2 shore durometer hardness of less than about eighty to eighty-five. The sphere has a smooth polyurethane surface skin, with the surface of the sphere being provided with a regular pattern comprising a multiplicity of cup-like or hemispherical depressions substantially covering the surface. The baseball has the advantage of durability as well as the advantage of being formed economically in one operation from a homogeneous composition. The cup-like depressions enable the ball to travel greater distances than would be expected for the resilient material, and enhance the accuracy with which the ball can be pitched, bringing the ball substantially within the range of initial performance of a conventional or regulation baseball. The ball is pitched in a pitching machine providing backspin and the depressions appear to cause turbulent airflow enhancing lift and drag factors on the ball as well as stabilizing its flight path. The ball resilience further enhances the ease with which it is manufactured since the ball can be easily removed from a simple mold despite the presence of mold projections used to form the aforementioned depressions.