The invention relates to an extruded conduit profile, which has a U-shaped cross section and comprises a base and limbs, said limbs being shaped on the base as one piece. The profile also has a covering part, which can be connected to the free ends of the limbs.
Such conduit profiles are widely known. They serve as installation conduits for the installation of electrical lines or mains, are used when such lines are being installed in walls or ceilings, serve as parapet conduits and have many other applications.
A conduit profile of such type is know from German patent 77 02 117. Here, an installation conduit is described comprising a U-shaped housing for receiving wires, cables, lines, hoses and suchlike having a covering part for covering the housing. In the free end areas of the sidewalls of this installation conduits slots are formed which extend in longitudinal direction and serve for the placing of retaining clips.
With respect to such conduit profiles, it is the endeavour of manufacturers and users to keep the wall thickness of the profiles at the lowest possible level. Due to the required stability during manufacturing and installation, this endeavour is relatively limited.
Therefore, it is suggested in DE 82 31 934 U1 to form the base and/or the sidewalls and/or the covering or the conduit profile at least partially as hollow chamber profile. This suggestion assumes that hollow chamber profiles generally have a high stability and are if low weight so that the desired material saving can be achieved in such a manner. However, it has been ignored that such hollow chamber profiles have two continuous walls with interconnected webs serving as space retainers so that the material saving, if any is achieved after all, is relatively low.
It is the object of the present invention to provide a material saving manufacturing of such conduit profiles and at the same time to retain the required stability. It is suggested according to the invention that at least the base of the U-shaped conduit profile has a reduced wall thickness and that impressions serving the reinforcement in sections are placed inside this wall thickness-reducing base.
The invention draws on the ample knowledge gained, for example, in the manufacturing of corrugated pipes. Here, substantial reductions in the cross section of the pipe walls have been achieved by forming corrugations so that corrugated pipes could be manufactured at substantially less material expenditure at comparative strength relative to compact pipes. At the core of the invention is a type of transversal corrugation for generating transversally extending ribs, at least in the base area of the U-shaped conduit profile. According to the invention, this transversal corrugation can be manufactured by means of stamping, punching, via vacuum link chains or by means of differing thrust during extrusion.
It is essential for its operation that the transversal corrugations are placed in the wall areas having a weakened cross section. Hereby, it can be of advantage that limbs which have a thicker cross section relative to the base extend slightly into the base with the wall thickness in the deflection area to the base and that the impressions extend from the wall thickness of the deflection area. The strength extending from these impressions runs into the thickened sidewall, here preferably into the radius area.
Impressions in the form of a cross or T or such like can be placed into the wall thickness-reduced base in addition to the corrugated shape or instead thereof. Star shapes, circles, polygons etc can be placed into the wall thickness-reduced base. The impressions can be provided in planar shape or reinforced in prism shape at the plane of maximum load, ie the bending moment.
It is particularly advantageous if, in addition to the undulated impressions, circular formations are placed into the base, which contribute to a further increase in stability. Such circular formations can be designed with a raised edge whereby, for example, a screw head of an attachment screw can be sunk into the such formed interior space. Thereby, in addition to the stability increase, a damage of the lines which are to be pulled into the lumen of the conduit profile over a, for example, sharp-edged screw head, is prevented.
The impressions according to the invention can be placed into the base and/or into the limbs and/or the covering part. In addition to reinforcement characteristics, transversal corrugations in the covering, as long as they are placed sheet-like, can serve as raised base on the covering for advertisements such as company names, system names, marks of conformity etc.
The impressions according to the invention can be placed into the corresponding wall thickness-reduced wall areas and spaced at arbitrary distance. The impressions can also be provided as a hybrid, namely once as transversal corrugations crosswise to the longitudinal axis of the conduit profile in the base, in the limbs and/or the covering and additionally in round, cross-, star-, T-shaped and polygonal impressions.