| 20090163307 | BAT FOR BASEBALL OR SOFTBALL AND MANUFACTURING METHOD THEREOF - A baseball or softball bat which enables a ball to fly farther than a conventional bat. The bat is made of metal, wood or carbon fiber-reinforced plastic and its cylindrical ball-hitting part has an axial cross section shape as follows: a lot of concave-surfaced grooves and convex-surfaced ridges are arranged in parallel alternately along the circumference of the bat and the convex parts are round and curved outward. The concave and convex parts are covered by a cylindrical sheet of polyurethane elastomer or similar material. Also, a metal baseball or softball bat is manufactured by grooving the cylindrical ball-hitting part surface by a lathe using a roller. | 06-25-2009 |
