BRACING TRUSS FOR CONCRETE OR MASONED STRUCTURAL LAYERS AND METHOD FOR MANUFACTURING THE SAME

Abstract: The invention relates to a truss bracing concrete or masoned structural layers together and to a method for manufacturing the truss. The truss is used e.g. in a thermally insulated prefabricated element for binding inner and outer element layers (1, 2) to each other through an insulation (3). The truss is manufactured from a blank sheet, which is provided with slits and the blank is stretched in a direction perpendicular to the slits. The slits are disposed and arranged to develop, after stretching of the blank, substantially parallel chords (5) and diagonal braces (6) therebetween, the latter being stretched during the stretching operation.

Description: Bracing truss for concrete or masoned structural layers and method for manufacturing the same The present invention relates to a truss bracing concrete or masoned structural layers together. The invention relates also to a method for manufacturing such a truss . In a preferred embodiment, the invention relates to a truss for a two-plate thermally insulated prefabricated element for bracing together the inner and outer layers of the element through an insulation. The traditional truss has been manufactured in such a way that separate steel chords are resistance welded to a bent diagonal wire, the product being compiled from three components . An object of the invention is to provide an improved truss, which is lighter, stronger with respect to its weight, builds a weaker cold bridge between the plates, and is more manufacturing friendly. This ob ect is achieved by means of a truss of the invention, the characterizing features of which are set forth in the appended claim 1 or 2. The truss can be manufactured preferably by means of the method defined in the appended claim 3. The invention will now be described in more detail with reference made to the accompanying drawing, which illustrates m section a prefabricated element fitted with a truss of the invention. The element consists m a conventional manner of inner and outer layers 1 and 2 with a thermal insulation 3 therebetween. The layers are tied to each other by means of a truss 4, comprising boundary, substantially parallel chords 5 and diagonal braces 6 therebetween, the number of which can be e.g. three per meter in either direction. The chords 5 are embedded in cast concrete and the diagonal braces 6 are set in junctures between the insulations. The diagonal braces 6 and the chords 5 are manufactured from a single blank, such that there are no welding joints at crossing points 7 of the diagonal braces or at junctures 8 between the same and the chords. This is made possible in such a manner that a blank of sheet material is cut to provide it with slits, the disposition of which is such that, as the blank is stretched from the chords 5 in a direction perpendicular to the slits, the diagonal braces 6 stretch to a sufficient extent for achieving a desired width for the truss. Thus, the direction and positioning of the slits is such that, during the stretching, the diagonal braces cannot experience flattening or bending. The blank sheet may have a material thickness which is quite small, e.g. 1-2 mm. The method differs from traditional manufacturing of a meshed structure essentially in the sense that stretching of the entire slit area is effected in a single operation by distancing the chords 5 from each other while the diagonal braces remain substantially coincident with the plane of the original sheet With respect to the traditional truss structure, the invention offers the following advantages: - a lighter structure - no structure-weakening and possibly corrosion-inflicting welds - increased number of diagonal braces and crossing points thereof results in a structure which is lm- proved in terms of material strength - structure is lightened even further as a result of shape-strengthening occurring as the diagonal braces are stretching - a thinner structure builds a weaker cold bridge between the plates - more friendly in terms of manufacturing. The invention is not limited to the above-described exemplary embodiment, but the truss can also be used for bracing on-site masoned brick walls to each other, the chords 5 being embedded in mortar between brick layers, or - in a floor slab for binding to the slab a concrete layer to be cast on top of the slab.

Claims: Claims 1. A truss bracing concrete or masoned structural layers together, c h a r a c t e r i z e d in that a truss (4) consists of a solid sheet material and it includes substantially parallel chords (5) and diagonal braces (6) therebetween . 2. A truss for two-plate thermally insulated prefabricated element for bracing inner and outer element layers (1, 2) to each other through an insulation (3), c h a r a c t e r i z e d in that a truss (4) consists of a solid sheet material and it includes substantially parallel chords (5) and diagonal braces (6) therebetween. 3. A method for manufacturing a truss as set forth in claim 1 or 2, c h a r a c t e r i z e d in that a blank sheet is cut to provide it with slits and the blank is stretched in a direction perpendicular to the slits, said slits being disposed to develop substantially parallel chords (5) and diagonal braces (6) therebetween, the latter stretching during said stretching operation, such that the chords (5) are set at a distance from each other matching a desired width for the truss .

Inventors: LAMMINMAEKI PAULI, LAMMINMAEKI, PAULI
Applicants: LAMMINMAEKI PAULI, LAMMINMAEKI, PAULI
Application year: 1997
Main classification: E04B1
IPC codes: B21D47, E04B1, E04B5, E04C3, E04C5