AU6575580A - Beam - Google Patents

Description

Beam

This invention relates to a beam comprising a web and flanges extending therefrom.

A great number of beams with I-, C- or Z-shaped cross- -section are already knoi . The simplest type of such beams has a web with con¬ stant material thickness. This implies, however, a rela¬ tively high material consumption with resulting high dead weight, relatively seen.

Beams of the aforesaid type further are known, at which the web is provided with embossments or profilations. Also in this case, however, the material thickness of the web is constant, which results in that either the connect¬ ions between the web and the flanges are dimensioned too weak or the central portion of the web is dimensioned too strong.

The present invention has the object to produce a beam of the kind referred to above, at which the different portions of the web are dimensioned correctly for their function. This is achieved by a beam, which has been given the characterizing features defined in the attached claims. An embodiment of the invention is described in the following, with reference to the accompanying drawings, in which Fig. 1 shows a beam according to the invention by way of a perspective view, Fig. 2 is an end view of the beam according to Fig. 1, Fig. 3 is a section along the line III-III in Fig. 2, Fig. 4 is a prespective view of a modified embodiment of the invention, and Fig. 5 is a per¬ spective view of a further embodiment of the invention. The beam shown in Figs. 1-3 comprises a web 2 with two flanges 3 connected to the web 2, which flanges extend perpendicularly relative to the main plane of the web 2. The flanges are in parallel with each other.

The web 2 is provided with a plurality of embossments or profilations 4, which at the embodiment shown extend perpendicularly to the longitudinal direction of the

SUBSTITUTE SHEET beam 1.

As appears from Figs. 1-3 the embossments do not extend all the way to the flanges 3, but the two outermost longitudinal portions 5 of the web 2 are not profilated. It also appears from the Figures that the sheet metal thickness in the embossed portion of the web 2 is sub¬ stantially smaller than the longitudinal outer portions of the web 2. The sheet metal thickness in the embossed port¬ ion should be at maximum half the sheet metal thickness in the outer portions for yielding the beam according to the invention to be economically of interest.

Due to the fact that the portion of the web 2 with smaller sheet metal thickness is embossed, it acts as an embossed web having a sheet metal thickness doubled many times over with respect to resistance against torsion, breaking, etc.

The beam 1 according to the invention, thus, has a web 2, which in necessary respects acts as a web with constant sheet metal thickness, in spite of the consider- able material saving obtained.

In addition to the advantage of cost saving for material, the further advantage is obtained that the beam 1 according to the invention has a lighter weight than a beam with a homogenous web. This is of extreme im- portance from a load and handling aspect.

Due to the fact that web 2 of the beam 1 according to the invention has maximum thickness at the connections 5 to the flanges 3, a very good capacity of taking up pressure, tensile and shearing forces in these connections 5 is obtained.

At the embodiment shown, the outer contours of the embossed portion are spaced from each other with a dis¬ tance, which is equal to the thickness of the connecting portions 5. The said relative distance, however, may also exceed the thickness of the connecting portions or even be smaller than said thickness.

In Fig. 4 a different type of I-beam according to

SUBSTITUTE SHEET the invention is shown, viz. a so-called saddle beam 1 ^• . As appears from Fig. 4, the upper flanges 3' do not extend in parallel with the lower flange 3". The distance between the upper flanges 3' and the lower flange 3" is the greatest at the longitudinal central point of the beam 1 ' .

As appears from Fig. 4, the embossments 4' form a herringbone patter. The reason thereof will be explained below.

In Fig. 5 a further saddle beam 1" -is- shown, which like the beam 1' according to Fig. 4 has upper flanges 3^l, which do not extend in parallel with the lower flange 3". The web 2" of the beam 1" according to Fig. 5 shows embossments or profilations 4", which are inclined at a certain angle relative to the lower flange 3". The emboss- ents or profilations 4" change the direction of inclina¬ tion at the longitudinal central portion of the beam 1".

The beam according to the invention preferably is manu¬ factured by rolling and embossing in hot state.

The first step in the manufacturing process is to produce by rolling a blank, which consists of a web with longitudinal- outer portions and an intermediate portion, which has a considerably smaller thickness.

The blank may have flanges connected to the outer portions, or the flanges may be attached later on, for example by welding or glueing.

The aforesaid blank is treated further in that, still in hot state, the intermediate thinner portion is embossed to desired section height.

Due to the embossing in hot state of the blank, yield- ing takes place in the central portion of the web whereby a certain thinning of the material is effected. This thinn¬ ing, however, can be neglected.

According to an alternative manufacturing method, a blank is produced by rolling which has a web with constant material thickness. This blank may in a corresponding way to the aforesaid method either have flanges, or the flanges can be attached lateron.

SUBSTITUTE SHEET At this variant the embossing or profilation brings about a material thinning of the central portion of the web, The excess material resulting therefrom is taken care of in a suitable way. It can be imagined, for example, that the height of the web is increased in connection with the em- bossing or profilation.

At the manufacture of the saddle beam according to Fig. 4, it is preferably proceeded from a beam according to Fig. 1. Thereafter a cut is made in the web 2 after the dash-dotted line A-A.

By turning, for example, the upper beam half end to end, the lower ends will be located directly in front of each other, and the higher ends will be located in front of each other. The cut surfaces of the web are now joined again, preferably by welding, whereby one half of the saddle beam shown in Fig. 4 has been obtained after the ends had been cut-out.

The embossment portions in the upper and, respect¬ ively, lower halves thereby form a certain angle with each other, and the embossments 4' show a trestle in their longitudinal central portion. This is the explanation of the herringbone pattern obtained. The other half of the beam 1' according to Fig. 4, of course, is manufactured in a corresponding manner, whereafter these halves are joined together, preferably by welding.

At the manufacture of the saddle beam shown in Fig. 5, it also is proceeded from an I-beam with parallel flanges. The embossments, however, are inclined to the flanges. The degree of inclination of the embossments is determined by the inclination, which the upper flanges 3' of the beam 1" according to Fig. 5 shall have. For obtaining straight em¬ bossments 4", the embossments in the beam, from which the manufacture proceeds, with parallel flanges, must form a right angle with the cutting line (A-A in Fig. 1) along which the starting beam is divided. The inclination of this cutting line determines the inclination of the upper flanges of the saddle beam.

OMPI

SUBSTITUTE SHEET ^ Ss In this connection it is to be pointed out that the design principles of a beam stated in the present invention are especially applicable to saddle beams.

The outer portions 5' of the web 2', 2", namely, are maintained intact at both ends of the saddle beam 1', 1". This is extremely important because these outer portions are needed for taking up the relatively great shearing forces arising at the ends of the beam.

The invention is not restricted to the embodiments described above.

The embossments, for example, must not have the form shown in the Figures.

At the above embodiments the beams shown have I-cross- section. The invention, however, is not restricted there¬ to, but the beams may have, for example, C- or Z-shaped cross-section.

The invention may also in other respects freely be varied within the scope of the attached claims.

SUBSTITUTE SHEET

Claims (6)

1. A beam comprising a web (2, 2¹) and flanges (3, 3', 3") extending from the web (2, 2'), c h a r a c t e r i z e d in that the web (2, 2') is provided with embossments or profilations (4, 4', 4") in its longitudinal central portion, and that the material thickness of the embossed portion is substantially smaller than the material thickness of the portions (5, 5') of the web (2, 2') adjoining the flanges

(3, 3*, 3").

2. A beam as defined in claim 1, c h a r a c t e r¬ i z e d in that the embossments or profilations (4, ^», 4") have trapezoid cross-section.

3. A beam as defined in claim 1 or 2, c h a r a c ¬ t e r i z e d in that the material thickness in the conn¬ ecting portions (5, 5'} is at least twice as great as the material thickness in the embossed or profilated portion.

4. A beam as defined in any one or more of the preceding claims, c h a r a c t e r i z e d in that the embossments or profilations (4) extend perpendicularly to the flanges (5) .

5. A beam as defined in any one or more of the claims 1-3, c h a r a c t e r i z e d in that the upper flanges (3¹) and lower flanges (3") do not extend in parallel with each other, and that the embossments or profilations (4¹) at least in some portion are perpendicular to the lower flange (3") .

6. A beam as defined in any one or more of the claims 1-3, c h a r a c t e r i z e d in that the embossments or profilations (4") form an angle with the lower flange C3") which is not a right angle.

SUBSTITUTE SHEET