Stretch roll forming apparatus using frusto-conical rolls

A stretch roll forming apparatus comprising a plurality of roll forming stations, said roll forming stations being serially disposed so that a sheet metal workpiece can be advanced through each of said stations in sequence;

• each station including a pair of roller dies supported by an inboard support station and by an outboard support station, in a spaced apart relationship, so as to each be rotatable about a horizontal axis, said roller dies being configured to shape a sheet metal workpiece which is advanced therebetween;
• at least one of said roll forming stations comprising a stretch roll forming station wherein said roller dies each have a frusto-conical shape, said roller dies being disposed so that the taper of a first one of said roller dies extends from the inboard support to the outboard support, and so that the second of said roller dies is disposed so that its taper extends from the outboard support to the inboard support;
• whereby a sheet metal workpiece which is advanced between said roller dies of said stretch roll forming station has a first longitudinal edge thereof stretched relative to a second longitudinal edge thereof, so as to impose a longitudinal curvature thereupon;
• and
• a sweep station which is operative to impose a curvature on said sheet metal workpiece in a horizontal plane which is perpendicular to said longitudinal curvature;
• whereby said stretch roll forming apparatus is operative to impose curvatures on said sheet metal workpiece in two planes which are perpendicular to one another.