| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a grip end capable of easily adjusting the weight by controlling the wall thicknesses of a bottom part and a side wall part. <P>SOLUTION: This method for manufacturing the hollow grip end 1 disposed at the end of a grip 80 in a bat 8 for a ball game is characterized in having a forging process of molding a cup-shaped intermediate body 101 having the bottom part 11 and the side wall part 12 cylindrically raised from its outer circumferential end by forging a material 10 composed of a disk-shaped mass, and a drawing method performing a drawing process to the side wall part 12 and bending it inward. The forging process is executed by compressing the material 10 disposed in a machining hole 60 by a punch 7 using a die 6 having a bottomed machining hole 60 with an inside diameter D1 corresponding to the outside diameter of the material 10, and the punch 7 having the external shape D2 smaller than the inside diameter D1 of the machining hole 60; and the thickness of the bottom part 11 of the intermediate body 101 is adjusted by a relative advancing distance of the punch 7 to the die 6. <P>COPYRIGHT: (C)2007,JPO&INPIT |
