Roll forming machine

A roll forming machine for forming sheet metal of a given range of thickness comprising a plurality of forming units disposed sequentially along a work path and adapted to form said sheet metal into a given shape in a series of progressive deformations, each of said forming units including a frame rotatably supporting a lower roller about a first axis of rotation, said lower roller including working surfaces provided by a bending portion and a holding portion defining a predetermined angle therebetween, an upper roller having two frusto-conical peripheries divided by a transverse median plane and disposed in confronting relation to the working surfaces of said bending and holding portions of said lower roller and spaced therefrom by a distance corresponding substantially to a given thickness of said sheet metal, said frusto-conical peripheries defining an angle therebetween corresponding substantially to said predetermined angle, swingable means for mounting said upper roller in said frame such that when said upper roller is in confronting relation to said lower roller its axis of rotation is inclined to said first axis, and means for moving said swingable means to swing said upper roller along an arcuate path having a tangent which substantially bisects said predetermined angle in order to vary the distance between said upper and lower rollers and thereby accommodate sheet metal of different thicknesses within said range.