US Patent 7181945 Semi-manufacture pulley forming apparatus

A pulley is made by fixing an edge of an opening of a plate by using a first upper mandrel ring installed at a lower end of a first supporting pin of a first forming device. A supporting block disposed around an upper end of a first spindle is rotated with the first spindle. An inner hub of the pulley is formed by inwardly pressing an upper surface of the plate against a first pressing roller to reduce the thickness of the plate while drawing the plate around a first mandrel ring. The plate is fixed to a second spindle of a second forming device, so the plate rotates with the second spindle. An outer hub is formed by pressing a convex bead toward the inner hub by using a fourth pressing roller and by drawing the outer hub.