| 摘要 |
A composite baseball bat has a unique tapered aluminum spar encased in polyurethane foam. The tapered spar is formed by swaging, starting with an aluminum tube whose outer diameter and wall thickness are those for the barrel section of the bat. A tapering portion is swaged to a decreasing outer diameter and increasing wall thickness, which is then constant over the handle portion of the bat. This construction yields far greater stiffness and freedom from objectionable vibrations.
|
