MANUFACTURE OF PIVOT FOR JACK, MANUFACTURE OF JACK, AND PIVOT FOR JACK, AND JACK

摘要

PROBLEM TO BE SOLVED: To provide a method to manufacture a pivot for jack in which defects of known methods to manufacture the pivot for jack are solved, and the pivot can be rapidly manufactured at a low cost. SOLUTION: A cylindrical work 5 formed of ductile metallic material is turned and rolled by contour rollers 13, 14. At least one of the contour rollers 13, 14 is pressed against the work 5 using a hydraulic pressure regulating device 20. The contour rollers 13, 14 are provided with an annular rib 17 to generate two annular groove parts 31 in the work 5 when being rolled.