| 摘要 |
<p>PROBLEM TO BE SOLVED: To form lock grooves by preventing split of a headrest pillar while avoiding increase in plate thickness of the headrest pillar when the lock grooves are molded, on a leg part protruding from a cushion part of the headrest pillar formed of a pipe, by a core metal that has molding grooves and is removably inserted into the leg part, and punches that can push the side wall of the leg part into the molding grooves.SOLUTION: Molding grooves 31 and 32 are formed larger in the longitudinal direction of a leg part 10a than final molding shapes of lock grooves 13 and 14. After the side wall of the leg part 10a is pushed, by punches 22 and 23, into the molding grooves 31 and 32 of the core metal 24 inserted in the leg part 10a, the core metal 24 is reciprocated in the longitudinal direction of the leg part 10a, so that both ends of the lock grooves 13 and 14 along the longitudinal direction of the leg part 10a are formed by the punches 22 and 23 and the molding grooves 31 and 32.</p> |
