EP0420084B1 - Box-girder for a crane girder - Google Patents

Description

The invention relates to a box girder according to the preamble of the main claim.

A generic box girder is described, for example, in US Pat. No. 3,241,285 and EP 0 293 789 A1. In both known devices, it is necessary to provide reinforcement plates within the carrier formed, which are welded to the inside of the concave web plates. The well-known shape of the box girder achieves a high degree of stability and rigidity as well as torsional security, but the production of these box girders is quite complicated due to the internal welds.

The invention has for its object to provide a box girder that is easier to manufacture with equally good stability and torsional rigidity and is therefore cheaper to produce.

This object on which the invention is based is achieved by the teaching of the main claim. Advantageous configurations are explained in the subclaims.

In other words, it is proposed that the web plates are formed from individual plates, one of which runs from the upper chord to the lower chord, while two only run from the upper chord to the continuous single plate or from the lower chord to the continuous single plate. This makes it possible for these three sheets to be welded to one another, the weld seams being on the outside and thus making it easy to "submerged arc welding".

In a first embodiment, the single sheet runs in a straight line diagonally between the upper chord and lower chord and the two subsequent individual sheets can therefore be welded on from the outside after the carrier has been rotated accordingly.

In a modified embodiment, the continuous sheet metal is placed in the middle perpendicular to the plane of the upper and lower chord and welding from the outside is also possible here. Finally, it is proposed according to the invention that only a single weld seam is provided in the central region, with which the two individual sheets are fixed to the continuous single sheet. The continuous single sheet has a V-shape.

The arrangement according to the invention ensures that the appearance of the wearer - as in the case of known carriers - is maintained, but that a more economical production is possible. In addition, the arrangement according to the invention has the advantage that the weld seams are better and easier to control.

Fig. 1

eine erste Ausführungsform eines Kastenträgers, in

Fig. 2

eine zweite abgeänderte Ausführungsform eines Kastenträgers und in

Fig. 3

eine wiederum abgeänderte Ausführungsform.

Embodiments of the invention are explained below with reference to the drawings. The drawings show in

Fig. 1

a first embodiment of a box girder, in

Fig. 2

a second modified embodiment of a box girder and in

Fig. 3

another modified embodiment.

In the drawings, a box girder is shown, which has an upper flange 1, a lower flange 2 and web plates 3 and 4 connecting the two belts. In a manner known per se, these web plates 3 and 4 are designed as concave angular profiles.

In all three exemplary embodiments, the web plates 3 and 4 consist of individual plates 5 and 6 as well as 7, 7a and 7b.

In the embodiment according to FIG. 1, the single sheet 7 runs from the underside of the upper chord 1 to the inner side of the lower chord 2, diagonally and thus includes an angle α of less than 90 ° with the upper chord and the lower chord. The two individual plates 6 and 5 are then welded to this diagonally running individual plate 7 and it is readily apparent from the drawing that the welds are on the outside and can therefore be easily manufactured and checked.

To produce the weld seams, the actual support is placed in a so-called trough position and then problem-free "submerged arc welding" is possible.

It can also be seen from the illustrations that the individual sheets 5 and 6 also connect at an angle β to the underside of the upper chord 1 or the inside of the lower chord 2, which is less than 90 °.

This configuration creates an X-shaped box girder.

In the embodiment according to FIG. 2, the single sheet 7a again runs diagonally between the upper chord 1 and the lower chord 2, and this sheet can also be easily welded onto the upper chord 1 and the lower chord 2 from the outside. However, the sheet itself is approximately Z-shaped, i.e. it has a central region 8, which runs perpendicular to the plane of the upper chord 1 or the lower chord 2. The ends of the individual plates 6 and 5 adjoin this straight-line central region 8 and these individual plates are again easy to weld from the outside.

In the embodiment according to FIG. 3, the single sheet 7b consists of a V-shaped edged profile component which is easily welded from the outside to the underside of the upper chord 1 and the inside of the lower chord 2. The two individual sheets 5 and 6 are welded in the area of the apex 9 of the single sheet 7b.

Claims (4)

1. A box girder comprising an upper flange (1), a lower flange (2) and lateral web plates (3, 4) arranged between the upper and lower flanges (1, 2), said web plates (3, 4) being constructed as concave angle sections, characterized in that the web plates (3, 4) are formed of three individual plates (5, 6; 7, 7a, 7b), one of which individual plates (7, 7a, 7b) runs through in one piece from the upper flange (1) to the lower flange (2) and forms an angle ó of less than 90° with the underside of the upper or lower flange (1, 2), while the other two individual plates (5, 6) each run from the upper or lower flange (1, 2) respectively to the individual plate (7, 7a, 7b) and likewise form an angle β of less than 90° with the underside of the upper or lower flange (1, 2).
2. A box girder according to claim 1, characterized in that the individual plate (7) runs in a straight line diagonally between upper and lower flanges (1, 2).
3. A box girder according to claim 1, characterized in that the individual plate (7a) runs diagonally between upper flange and lower flange (1, 2), but comprises a central area (8) which is perpendicular to the plane of the upper flange (1) or the lower flange (2).
4. A box girder according to claim 1, characterized in that the individual plate (7b) is of V-shaped construction and the two individual plates (5, 6) adjoining the upper or lower flange (1, 2) respectively adjoin the outside of the apex (9) of the individual plate (7b).

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