Abstract: A supporting framework has at least one roller which is carried by a carrying frame. The roller has an axis positioned generally along the horizontal direction in the use position. An axial extension projects out of each opposite end of the roller. The carrying frame has a pair of opposite, generally vertically extending bearing limbs, each bearing limb having a bearing opening. Each axial extension of the roller extends into one of the bearing openings of the bearing limbs. Lateral guide elements are provided at the two opposite ends of the roller. Each lateral guide element has a radially projecting lug which can be moved between an active position and an inactive position. The lugs can prevent a workpiece from moving past the ends of the roller when the lugs are in the active positions.