Edge roll assembly for manufacturing a taper leaf spring

In an apparatus for manufacturing a taper leaf spring from a sheet of spring material, the sheet having top and bottom surfaces and side edges, the apparatus rolling side edges of the sheet to control the breadth of the leaf spring and subsequently rolling at least one of the top and bottom surfaces to control the taper of the leaf spring, the improvement wherein the apparatus includes edge roll assemblies for rolling side edges of the sheet, each of said edge roll assemblies having a concave main roll body for shaping side edges of the sheet to form side edges of the leaf spring and confronting regulating flanges parallel with each other extending outwardly from outer terminal peripheries of the main roll body, the regulating flanges constraining expansion of the sheet in the thickness direction resulting from rolling in the breadth direction thereby regulating thickness of the sheet and increasing elongation of the sheet ahead of a portion thereof being rolled.