Abstract: Apparatus for making folds or bends of adjustable length in sheet metal. The apparatus includes a retractable chain-like die which can be shortened or lengthened so as to adjust the operative length of the die.

Abstract: This disclosure relates to a roll forming machine having a plurality of sequentially-arranged forming units adapted to progressively bend edges of metal sheet into a given shape. The forming units include upper and lower rollers between which the metal sheet is fed and having axes of rotation inclined to one another. Each of the lower rollers includes a bending portion and a holding portion defining a predetermined angle therebetween. The upper roller has two frusto-conical peripheries disposed in confronting relation to the working surfaces of the lower roller and spaced therefrom by a distance corresponding to the thickness of the sheet metal. In order to accommodate sheet metals of different thicknesses, the spacing between the upper and lower rollers may be varied by mounting the upper roller on a swingable mounting means whereby the upper roller is swung along a relatively short arc which approximates a linear path bisecting the angle defined by the working surfaces of the lower roller.