| 摘要 |
An elongated member, for example, a bowling pin, has a core of foamed plastic material, which has areas of greater density, generally toward the lower end of the bowling pin, so as to provide desired weight distribution along the member. In the bowling pin, providing a denser core area near the bottom lowers the center of gravity. In a baseball bat, the increased density can be provided in the "sweet spot" area, if desired. In producing the variation in density, the mold in which the foamed core is formed is heated in those areas in which the density is to be light and chilled in those areas in which the density is to be increased. In making a baseball or softball bat, a foamed core can be wrapped directly with graphite filament or graphite and glass filaments, or synthetic fibers such as Aramid fibers of the type marketed by Dupont de Nemours as KEVLAR TM either dry wrapped and subsequently embedded in epoxy or the like, or wrapped with adhesive coated fiber that is then cured.
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