| 摘要 |
PURPOSE: To provide a baseball bat excellent in repulsion characteristic by setting the ratio between the total" length of the bat and the length of a quasi- parallel section to a specific range. CONSTITUTION: The value of L/LT is set to 0.20-0.40 in a bat 1 having the maximum diameter DMAX and the outer diameter D at an optional position, where LT is the total length of the bat 1 and L is the length of a quasi-parallel section 10 including a complete parallel section 14 set with the outer diameter D to the value of DMAX-0.5mm or above. The compression rigidity per unit width of the quasi-parallel section 10 at the place except for the tip section to 65 mm from the tip of the bat 1 is set to 2.4-3.5kgf/mm. The value t/D is set to 0.042 or below, where (t) is the thickness of the quasi-parallel section 10 at the place except for the tip section to 65mm from the tip of the bat 1. The value LB/LT is set to 0.17-0.37, where LB is the length of a large-diameter section of the bat 1 where the change of the compression rigidity is set to a nearly constant value of 3% or below. |
