Patent ID: 7861911

Claim:
A method for welding a first and a second frame member utilizing friction stir welding, wherein said first frame member includes a first flange and a second flange extending in parallel from the first frame member and wherein said second frame member includes a first wall and a second wall extending in parallel from an end portion of the second frame member, said first wall having along a first end portion of said second frame member a first rebate with a first sunk surface facing outwards and a stepped wall forming a step from said first wall to said first sunk surface and said second wall having at said end portion a second rebate with a second sunk surface facing outwards and a stop wall forming a step from said second wall to said second sunk surface, wherein said first and said second sunk surfaces are substantially parallel to each other, the method comprising: arranging said first flange to extend further from first frame member than the second flange; introducing the second flange of the first frame member into the second rebate of the second frame member until an edge of the second flange abuts said stop wall of the second rebate; rotating the first frame member about a contact point working as a hinge between said edge of the second flange and said stop wall until an inward directed surface of the first flange slides along the first sunk surface of the first rebate of the second frame member so as to freely adjust an overlap of the first flange in relation to the first sunk surface of the second frame member, such that an edge of the first flange does not reach the stepped wall of the first rebate of the second frame member, wherein the first flange has a greater overlap of the first sunk surface of the second frame member than an overlap of the second flange of the second sunk surface in the arrangement; wherein a slidable contact between the first flange and the first sunk surface of the rotating frame members to compensate for dimensional deviations; and carrying out a friction stir welding between the first frame member and the second frame member to form a welded joint along the edge of the second flange.