Abstract: The invention provides a device for putting et least two sheet blanks (2 and 3) in register edge to edge in a plant for welding these sheet blanks by means of a high energy density beam (1). The device comprises a longitudinal stop element (92) movable, on one hand, by the action of a first control means (100), between a retracted horizontal first position and a retracted vertical intermediate second position and, on the other hand, by the action of a second control means (110), between said intermediate second position and a vertical third position for putting in register the first sheet blank (2), in which position a lower part of the stop element (92) is gripped between the means for positioning and clamping the sheet blanks and an upper end part of the stop element (92) extends above a horizontal reference plane for positioning the edge to be welded (2a) of the first sheet blank (2) on the axis of the high energy density beam (1).