Patent ID: 8042368

Claim:
Method for the production of a longitudinal seam welded hollow profile from a sheet-metal blank with defined longitudinal edges wherein the sheet-metal blank is placed between two tool parts lying in a starting position in which they are apart, each provided with a recess determining an external shape of at least one section of the hollow profile that is to be produced, wherein a mandrel, whose external shape defines an internal shape of the hollow profile that is to be produced, is then positioned relative to the recess of one tool part such that a first gap is formed between a peripheral surface of the mandrel and an inside surface of the recess, a thickness of the first gap being slightly greater than a thickness of the sheet-metal blank that is to be shaped, wherein the sheet-metal blank is held in an area of the half that is distant from the mandrel, wherein the tool part adjacent to the mandrel is moved together with the mandrel, with the first gap intact, in the direction of the longitudinal edge of the sheet-metal blank that is distant from the mandrel such that the sheet-metal blank runs into the first gap along its longitudinal edge that is adjacent to the mandrel until it reaches an insertion limit, wherein the mandrel is positioned relative to the recess of the second tool part such that a second gap is formed between the peripheral surface of the mandrel and an inside surface of the said recess, a thickness of the second gap being slightly greater than the thickness of the sheet-metal blank that is to be shaped, wherein the tool part now adjacent to the mandrel is moved together with the mandrel, with the second gap intact, in the direction of the longitudinal edge of the sheet-metal blank that is distant from the mandrel such that the sheet-metal blank runs into the second gap along its longitudinal edge that is adjacent to the mandrel until it reaches an insertion limit and a slit profile that surrounds the mandrel about its peripheral surfaces is formed from the sheet-metal blank, wherein the mandrel is moved out from an interior of the slit profile, wherein the longitudinal edges of the sheet-metal blank that define the slit are welded together, the slit profile being supported by the tool parts, and wherein the tool parts are moved to their starting position in order for the finished welded hollow profile to be removed from the tool parts.