Method of making rim having opposite hollow flanges

摘要

Disclosed is a method of making a rim having hollow flanges formed on its opposite annular edges. It comprises the steps of: cutting an elongated metal band of a fixed width to provide metal strips of a predetermined length; rolling a selected metal strip into a ring; welding the opposite ends of the ring; curling each annular edge of the ring outward; and roll-forming the main annular part to define a well along the center line of the main annular part. The method further comprises the steps of: bending the opposite bead areas toward the center well; closing the gap between each curl edge and the counter bead area; and unbending the opposite bead areas into the final rim shape.