Apparatus for preparing the edges of metal sheets to be welded

Apparatus for preparing the edges of a metal sheet to be welded, said sheet having first and second main surfaces, comprising an assembly of metal working means, in particular milling cutters, being included in a unit associated with means for producing a relative movement between said sheet and said unit, during which movement said metal working means are working an edge of said sheet, characterized in that said means for producing said relative movement comprise, seen in the direction of the movement, a first set of rotatable rollers before and a second set of rotatable rollers after said metal working means, each set comprising at least three rollers which can be pressed against said main surfaces of said sheet, at least one roller of each set being disposed at the first main surface of the sheet and at least two rollers of the set being disposed at the second main surface of the sheet as well as being spaced from each other in the direction of movement in order, together with said at least one roller that is disposed at the first main surface of the sheet, to safely hold on to the sheet also when said metal working means have passed the end of the sheet edge being worked, and that at least one roller of each set of rollers is a driven roller that is positioned at an angle or angularly positionable in relation to the direction of movement and in a plane parallel to the sheet in order, during working of the sheet edge, to impart to the sheet not only a longitudinal component force bringing about said relative movement between the sheet and said unit, but also a transverse component force that urges the edge of the sheet and said metal working means against each other.