| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a boot of uniform thickness, which boot is of bellows type and to be mounted on a shift lever of an automobile. SOLUTION: A small port and a large port are formed on both sides of a substantially truncated conical body. A spiral projection 7 and a spiral groove 8 are formed on a peripheral wall of the truncated conical body to obtain a boot 1. The boot 1 is injection-molded by the use of a core 12 having a shape similar to the boot 1, and a longitudinaly dividable die 5 inside which an outer form of the boot is formed. In order for extraction, the small port 2 is rotated to the center of the spiral lines. The die, being a dividable type, enables extraction without damaging the projection 7 of the boot 1. As for the core 12, a large gap is formed by rotating the conical boot 1 for extraction, so that it is unnecessary to strongly press the groove 8 of the boot 1. |
