(57) Method in which a continuous butt-sealed rim of a collar defined by corresponding
concentric ends, without undulations, of a first wall, radially innermost, and a second
wall, radially outermost, of a double-wall bellows is obtained as a continuous butt-weld
bead on the corresponding rims, arranged radially adjacent to each other, of the ends
of the first and second walls, which have been prepared such that, before welding,
they are radially spaced apart from each other by not more than 0.3 mm and with the
rim of the second wall that projects in an axial direction with respect to that of
the first wall for a length of 0.2-0.4 mm; butt welding is performed with a laser
beam directed parallel to an axis of symmetry of the collar, making the latter rotate
around the axis to progressively expose the entire perimeter of the rims of the ends
of the first and second walls, simultaneously pressing the rims against each other
with a force between 1 and 3 kg via spring clamping rollers.
|
|
