Abstract: Tubing is made by advancing a flat metal strip in a travel direction along a path through a forming station and then through a soldering station and then through a cooling station. The strip is shaped in the forming station into a multilayer tubular shape by pressing it against a mandrel with a pair of forming rollers. Downstream the strip is engaged in the soldering station by a pair of contact rollers and electrical current is applied to the forming and contact rollers to flow via the forming and contact rollers through the tubular strip between the forming and contact rollers to heat the strip in the soldering station and thereby fuse layers of the tubular strip together. The forming rollers are rotated at a peripheral speed identical to a travel speed of the strip so that they do not slip on the strip, while the contact rollers are driven at a peripheral speed greater than that of the forming rollers. The soldered tubular strip is then cooled in the cooling station.

Abstract: A vacuum-cleaner pipe has an inner tube telescopingly received in an enlarged end of an outer tube. A retaining element diametrically opposite a slider which can be operated by the user can be received in an annular space between the tubes and on opposite sides of a guide body around which, in at least a partial turn, extends a bar spring which is braced against the guide body and not only provides the bias to the retaining element in the direction in which it presses a detent into a selected recess of a detent strip of the inner tube, but also forms the coupling between the slider and the retaining element so that upon movement of the slider in one direction, the retaining element is moved in the opposite direction.