The rear carrier structure has a support profile element (5) formed of a plurality of profile sections (20) having a profile cross-section open towards the front or rear side and at least two profile legs.

The channel section includes a plurality of riser portions connected to the pair of stringer elements.

The channel section defines a passageway for supporting runs of cable thereon.

Said supporting elements are themselves supported by bearings (3,4) that also have a triangular hollow profiled cross-section.

In order to set the desired profile height, the axis distance (A) between the rollers can be adjusted and in order to predetermine a profile diameter, the flank clearance between the sets of self-combing toothed wheel work can be adjusted.

The resulting metal beam can be an I-section beam or a box section beam.

The plastic profile is designed as a flat profile having a rectangular or square cross section.

The outer surface of this profile has a corrugated trend with respect to an axial cross-sectional plane of the profile.

The profiled rail section is also equipped with suspension elements.

To this end, the housing has a continuous profiled rail section (11).

Preferably the shaft is a square tubular hollow profile.

The coupling lever comprises a profiled element, which has a U-shaped cross-section, and a pin, which extends between the opposite legs of the profiled element.

The holding profile (3) and the cover profile (6) preferably have the same profile cross section and are mounted in a mirror‑inverted manner with mutually facing holding flanges (4).

The facing section (81) preferably extends in the direction of extrusion of the extruded profile.

The height of the flow guiding device to the profiled contour is at least 10% of a maximum thickness of the profiled contour for each transverse cross section.