| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve repulsive characteristic by inserting and fixing plural tubular insert members selected among metals, fiber reinforced plastics or the like in a hollow part of a bat main body ball hitting part to form a multilayer ball hitting part reinforcing tube layer. SOLUTION: Plural tubular insert members 5, 6 selected among raw materials such as metals like iron or fiber reinforced plastics, or the like are inserted and fixed in a hollow part 4 of a ball hitting part 2A of a bat main body 2 to form a multilayer ball hitting part reinforcing tube layer 7. For example, in the case of a metallic bat made of titanium or the like, the insert tube members 5, 6 are also formed by the same raw material as that of the bat main body 2. The lower end part 5c of a first insert tube member 5 is matched to the taper part 2E of a shaft part 2c of the bat main body 2 to perform preliminary forming in such a manner as to narrow down. When the first insert tube member 5 in which a second insert tube member 6 is inserted is inserted therein, the lower end part 5c is engaged with the taper part 2E. By this arrangement, repulsive characteristic can be improved.</p> |
