Method and device for the electric welding of sheets of multilayer structure

Device for the electric welding of at least two sandwich sheets each of the first and second sandwich sheets having a multilayer structure, each of the first and second sandwich sheets comprising at least two metal sheets that are mechanically interconnected by a film of polymer,

• comprising:
• first and second rollers, each of the first and second roller having a first cylindrical region and a second cylindrical region, the first cylindrical region of each of the first and second rollers having a smaller radii than the radii of the second cylindrical region of the same sheet, the second cylindrical region of the first roller opposing part of the first cylindrical region of the second roller, the second cylindrical region of the first roller opposing part of the first cylindrical region of the second roller, the second regions of each of the first and second rollers being electrically conductive,
• means for supplying electric power to at least said second part of each roller,
• means for rotating each roller, and
• means for displacing said rollers in a plane that is parallel to the axes of the first and second rollers and along a direction in the plane that is perpendicular to the axes.

A method for the electric welding of at least two sheets that each have a multilayer structure, termed sandwich sheet, each sandwich sheet having at least two metal sheets that are mechanically interconnected by a film of polymer, comprising the steps of:

• effecting a partial overlapping of said sandwich sheets to form an overlapping region of said sandwich sheets;
• putting faces, termed inner faces, of said sandwich sheets in contact with one another in said overlapping region;
• applying to opposite faces, termed outer faces, of said sandwich sheets, two rollers, each roller having first and second surface regions, the first and second rollers being in confronting relationship to one another and in alignment with said overlapping region, the first surface region of each of said rollers contacting an outer face of one of the sandwich sheets, the second surface region of each roller being displaced further towards the other roller than the first surface regions, the second surface region of each roller being electrically conductive and disposed in confronting relationship to the inner face the sandwich sheet which does not contact the first surface of same roller,
• electrically supplying power to at least said second part of each roller,
• exerting, by means of said rollers, a clamping force on said overlapping region of said sandwich sheets to bring said second part of each of said rollers in contact with said inner face of the confronting sandwich sheet, and shifting said rollers along said overlapping region.

A device for electric welding, comprising:

• first and second electrode surfaces, each of the first and second electrode surfaces having a first electrode surface region and a second electrode surface region, the first electrode surface region of each of the first and second rollers forming a step relative to the second electrode surface region of the same sheet, the plane of the first electrode surface region is offset from the plane of the second electrode surface region, the second electrode surface region of the first electrode surface opposing part of the first electrode surface region of the second electrode surface, the second electrode surface region of the first electrode surface opposing part of the first electrode surface region of the second electrode surface, the second electrode surface regions of each of the first and second electrode surfaces being electrically conductive;
• means for supplying electric power to the second electrode surface regions of the first and second electrode surfaces;
• means for rotating the first electrode surface about a first axis;
• means for rotating the second electrode surface about a second axis, wherein the first and second axes are parallel to one another and the direction of rotation of the first and second axes is opposite one another.