| 摘要 |
PURPOSE:To restrain impact vibration in hitting a ball for comfortable play while maintaining the lightness and rigidity of a conventional carbon fiber reinforced FRP racket by making a racket of a one-way fiber reinforced composite material having carbon fibers and polyvinyl alcohol fibers arranged alternately or laminatedly. CONSTITUTION:A necessary number of laminated prepreg sheets is wound around a winding core tube and a rod-like core composing material having the winding core integrally folded therein to mold a rod-like frame molding material. Then the winding core is withdrawn and the molding material is inserted and tightened in a molding metal mold to be worked curvedly into a desired racket frame shape. Then, an opening ends of the rod-like frame molding material corresponding to the terminal end of a shaft is placed adjacent to the outside of the molding metal mold. Under such a condition, 5.5kg/cm<2> of pressurized air is sent into the tube to expand the tube so that the prepreg is heated at 150 deg.C for 30 minutes to be set, and the racket frame is obtained which has hollow construction of an one-way fiber reinforced composite material having a shell formed of carbon fibers and polyvinyl alcohol system fibers. |
