Abstract: Methods for making curved pieces from continuous metal elements are provided. Such methods include advancing a continuous metal element through a calendering station such that each length of the element assumes a pre-established curvature; stopping advancement of the element after a curved length thereof has passed through a wrap-bending station located downstream of the calendering station; wrap-bending the length of the element located at the station, while simultaneously conveying the curved portion to a stretch-bending station; stretch-bending the curved portion; resuming advancement of the element until the wrap-bent length is at a cutting station; and cutting the element in the wrap-bent length, thus producing the desired curved piece. Curved pieces produced by such methods are also provided.

Abstract: Frames for vehicles, such as buses or industrial transport vehicles, are provided which may be formed by a plurality of welded elements including ribs, cross members and uprights. At least one upright maybe formed by a first section bar welded to a second section bar, thereby forming a closed, hollow cross-section. Methods of making and using such frames are also provided.