| 1. | Section bar of light metal, characterized in that it comprises at least one core (15) embedded in the section bar and of a material which has a higher tensile strength than the light metal used in the section bar, the core run 5 ning along the full length of the section bar. |
| 2. | Section bar of light metal according to claim 1, charac¬ terized in that the core (15) along its full length is anchored in the section bar by the material of the section bar engaging with the core (15). 0. |
| 3. | Section bar of light metal according to claim 2, cracte rized in that the core consists of a steel wire (15) and that the material of the section bar engages in the grooves in the envelope surface of the steel wire. |
| 4. | Section bar of light metal according to any of claims 5 13, characterized in that the core is arranged along one edge of the section bar (10A.11A). |
| 5. | Section bar of light metal according to any of claims 13, characterized in that the core (15) is arranged in the central portion (12) of the section bar. 0. |
| 6. | Section bar of light metal according to claim 5, the section bar being designed with a front side and a back side and being particularly intended for use as bearing beam in road railings, characterized in that the core (15) is arranged adjacent the backside of the section bar and 5 that the front side of the section bar has at least one s portion projecting in front of the core (15) and having an arcuate cross section. |
| 7. | Section bar of light metal according to claim 6, charac¬ terized in that the front side of the section bar is desig 0 ned with two portions (10,11) which have an arcuate cross section and which are arranged on either side of the cent¬ ral portion (12) of the section bar. |
| 8. | Section bar of light metal according to claim 7, charac¬ terized in that the two side portions (10,11) have Ushaped cross sections and that the legs (10B,11B) of the side por¬ tions are connected to the central portion (12) forming an obtuse angle (B). |
| 9. | Section bar of light metal according to claim 4, charac terized in that the section bar is provided with two cores which are arranged along each one of the longitudinal edges (10A,11A) of the section bar. |
| 10. | Section bar of light metal according to any of claims 69, characterized in that the section bar is adapted to be deformed in case of a shock load, before the core (15) or the cores are exposed to maximum load. |
The present invention relates to a section bar of light metal which is designed to take up heavy loads, par¬ ticularly shock loads, and which for example can be used as a load carrying beam in structural work or as a bearing beam in road railings. Background Art
It is previously known to manufacture supporting beams of light metal. However, these beams have a limited strength and admissible load, because the beams are defor¬ med under a heavy load and this deformation may cause burs¬ tings in the beams.
Furthermore, it is previously known to manufacture structural beams, particularly bearing beams for road rail- ings, of steel or concrete. Such beams, however, are diffi¬ cult to handle due to their high weight which makes the assemblage of the beams difficult and expensive. The steel beams are also expensi-ve to manufacture and are exposed to formation of rust, if they are not provided with an anti- corrosive painting that requires maintenance, and the beams of concrete are bulky which is a disadvantage when the spa¬ ce is limited. Disclosure of Invention
The main object of the invention is to provide a stif- fened section bar of light metal which has a higher strength and admissible load than prior section bars of light metal and which, for example when used in road rail¬ ings, can be substantially deformed without breaking, so that it can take up the loads which can arise in connection with traffic accidents.
Due to the fact that the section bar of light metal comprises at least one core which is embedded in the sec¬ tion bar and which consists of a material having a higher tensile strength than the light metal used in the section bar, a substantial increase of the strength of the section bar is obtained without a corresponding increase of the
weight or manufacturing costs of the section bar. Particu¬ larly, if the core of the section bar, which may consist of a steel wire, is embedded in the light metal during the manufacturing of the section b_ r and thus is firmly ancho- red in the section bar, a section bar of light metal having very good strength and admissible load is obtained * . If the section bar is further so designed that it is deformed during a shock load, before the core is exposed to maximum load, the section bar obtains properties making it very suitable for use as bearing beam in road railings. Brief Description of Drawing
One embodiment of a section bar of light metal accord¬ ing to the invention will now be further described below with reference to the accompanying drawing showing a cross section of a bearing beam for use in road railings. Best Mode for Carrying Out the Invention
The bearing beam shown on the drawing consists of an extruded section bar of aluminium provided with two arcuate edge portions 10,11 which are connected by means of a cent- ral portion 12. The central portion 12 forms the back side of the section bar, and the arcuate edge portions 10,11 project forward from the central portion 12 and form the front side of the section bar. The edge portions 10,11 have a substantially U-shaped cross section with two legs 10A.10B and 11A.11B, respectively, and a base 10C and 11C, respectively. The central portion 12 is connected to the edge portions 10,11 along the edges of the legs 10B and 11B, respectively.
The section bar is designed with a hollow projection 13 along the connection between the central portion 12 and the edge portion 11. The hollow projection has a longitudi¬ nal hole 14 in which a steel wire 15 is positioned. The projection 13 runs along the whole section bar in the long¬ itudinal direction of the section bar, and the steel wire 15 is completely embedded in the projection. The steel wire is positioned in the section bar of aluminium during the extrusion of the bar, so that the material of the bar enga-
ges in the grooves between the parts of the steel wire, thus anchoring the steel wire in the section bar along the full lenght of the bar.
The connecting legs 10B and 11B, respectively, of the U-shaped edge portions 10,11 form an obtuse angle β with the connecting central portion 12. This feature will provi¬ de a deformation of the section bar in case of a shock load on the front side, i. e. on the projecting edge portions 10,11. This deformation occurs by svinging the legs 10B,11B around the central portion 12. The deformation is provided before the steel wire is exposed to maximum load, and the¬ refore a vehicle, which for example in connection with a traffic accident is thrown against the bearing beam, is slowed down by the bearing beam in a somewhat flexible way, so that the risk of injuries to the person or persons tra¬ velling in the vehicle is to some extent reduced. The flex¬ ibility also entails that the strain on the steel wire and the attachment points is reduced which makes it possible to obtain a sufficient strength of the bearing beam by means of a comparatively thin wire and smaller means of attach¬ ment. Such a flexibility can not be obtained by conventio¬ nal bearing beams of steel or concrete and is a further advantage of the section bar of light metal according to the invention when used as bearing beam in road railings. In the section bar shown on the drawing the steel wire is embedded in the corner between the central portion 12 and the leg 11B of the edge portion 11, so that the steel wire is spaced from the central line 15 of the section bar. This will make ' the steel wire more efficacious than if it had been positioned on the central line of the section bar. Due to the fact that the steel wire 15 is embedded in the central portion 12 of the section bar, the edge por¬ tions 10 and 11 will be positioned on either side of the steel wire. Therefore, both edge portions 10,11 will be deformed in about the same way in case of an appearing shock load which will give a maximum flexibility of the section bar.
The section bar and possibly also the steel wire are attached at the ends to the posts of the road railing or to other convenient supports by means of conventional means of attachment (not shown). While only one embodiment of the section bar has been shown on the drawing and described above, it is evident that many different embodiments and variations are possible within the scope of the invention. It is for example pos¬ sible to replace the steel wire by a core of. another type, for example a bar which can have any cross section. The core can be embedded in the section bar either at the manu¬ facturing of the section bar or later when it can be pushed into the hollow 'projection of the section bar and attached to the section bar at a number of points. Instead of one single core two or more cores may be embedded in the sec¬ tion bar. When two cores are used, the cores are preferably positioned in the outer edges of the section bar, because the effect of the cores increases with the distance to the central line of the section bar. The section bar can also be designed otherwise than with two arcuate edge portions, for example with a single arcuate portion which than may extend in front of the core or the cores embedded in the section bar. However, when designing the section bar for road railings it is essential that the section bar is deformed in case of a shock load, so that the largest pos¬ sible flexibility is obtained when the bar is loaded.
The section bar according to the invention has been described in connection with road railings, but the bar can also be used in connection with other mechanical load sup- porting constructions, and the section bar has advantages, even if the load to be carried is not a shock load. In this case it is not necessary that the section bar is designed to be deformed when loaded. The section bar may be manufac¬ tured of other light metals than aluminium, and the core or cores do not need to be steel wires or steel bars. Also other materials having higher tensile strength than the light metal can be used.