Patent ID: 8631672

Claim:
Apparatus for continuous corrugation of a metallic tube, said apparatus comprising: a tool holder, rotating about an initially smooth tube and having a tool mounted concentrically with respect to said tube and forcing a corrugation into said tube during operation of said apparatus, said corrugation runs transversely with respect to a longitudinal direction of said tube, and said tool has a withdrawal device for movement of said tube in said longitudinal direction, a first hollow shaft is attached to said tool holder and projects in the pulling-off direction from it, surrounds said tube after the corrugation process and is rotated about its axis with said tool holder by an electric motor, and a unit including said tool holder and said first hollow shaft is mounted such that it moves in the axial direction, a second hollow shaft is arranged at a distance from said first hollow shaft and coaxially about the end, facing away from said tool holder, of said first hollow shaft, said second hollow shaft is mounted such that it rotates about its axis and is driven by said electric motor, and wherein in order to transmit force between said first hollow shaft and said second hollow shaft, a magnetic coupling is fitted, having two annular permanent magnets, arranged concentrically with respect to one another, a first permanent magnet and a second permanent magnet, wherein said permanent magnets are separated from one another by an air gap, and of which the first permanent magnet is attached on the outside to said first hollow shaft and the second permanent magnet is attached on the inside to said second hollow shaft.