WO2005123297A1

WO2005123297A1 - Method for producing expanded metal profiles and profile produced by the method

Info

Publication number: WO2005123297A1
Application number: PCT/EP2005/006190
Authority: WO
Inventors: Sergio Dallan
Original assignee: Dallan S.P.A.
Priority date: 2004-06-17
Filing date: 2005-06-09
Publication date: 2005-12-29
Also published as: ITVE20040029A1

Abstract

A method for producing expanded metal profiles, consisting of subjecting a metal strip of width less than the development of the profile to be produced to the following operations: forming longitudinal slits in at least that longitudinal band which is to form the central web of the profile, bending the edges of the slits, profiling said strip, transversely stretching that band containing the slits, pressing areas of said central web in correspondence with said stretched band to displace them external to the plane of said web, characterised by previously forming holes in correspondence at least with the ends of the lines along which slits are to be formed.

Description

METHOD FOR PRODUCING EXPANDED METAL PROFILES AND PROFILE PRODUCED BY THE METHOD The present invention relates to a method for producing expanded metal profiles, and a profile produced by the method. Metal structures, in particular C-shaped profiles, are known for supporting plasterboard or for forming shelves. Said profiles comprise along their central web a plurality of longitudinally aligned holes of various shapes obtained by a process of transversely stretching the sheet metal strip in which a plurality of slits have previously been formed. These known profiles present however certain drawbacks, and in particular:

- danger to the user handling the profile because of the cutting edges of the holes, - said cutting edges can damage connection cables passing through these holes,

- cracking can occur at the ends of the holes, to weaken the profile and compromise its strength. All these drawbacks are eliminated according to the invention by a method for producing expanded metal profiles as claimed in claim 1. A preferred embodiment of the present invention is described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a side view of an apparatus for implementing the method of the invention, Figure 2 shows the sheet metal strip on termination of the hole forming stage, Figure 3 is a cross-section on the line Ill-Ill of Figure 2, Figure 4 shows a sheet metal strip on termination of the incision stage, Figure 5 is a section therethrough on the line V-V of Figure 4, Figure 6 is a plan view of the sheet metal strip on termination of the bending stage, Figure 7 is a section therethrough on the line VII-VII of Figure 6,

Figure 8 is a plan view of the sheet metal strip on termination of the drawing stage, Figure 9 is a section therethrough on the line IX-IX of Figure 8, Figure 10 is a plan view of the sheet metal strip on termination of the stretching stage, Figure 11 is a section therethrough on the line XI-XI of Figure 10. Figure 12 is a plan view of the sheet metal strip on termination of the pressing stage, Figure 13 is a section therethrough on the line XIII-XIII of Figure 12, and Figure 14 is a cross-section through a profile. As can be seen from the figures, with the method of the invention the sheet metal strip, of width less than the development of the profile to be obtained, is unwound from a reel, and after being subjected to possible straightening operations, passes through:

- a pair of rollers 2 which form holes 6 and 8 respectively in the sheet metal strip 4 in correspondence with the regions to be slit,

- a pair of slitting rollers 10 which form in the strip a plurality of longitudinal slits 12, 14 of different length, aligned in parallel rows, - a pair of bending rollers 16 which, on the previously formed slits 12,14 form longitudinally slotted holes 18,20 with their edges bent towards the inside of the sheet metal strip,

- a pair of drawing rollers 22 having their punches shaped to curve the bent edges of the slotted holes to obtain a sort of radiused edging on each of said holes, with the tangent to its free edge forming an angle greater than 90° to the strip surface,

- a pair of stretching rollers 26 which exert transverse traction on the sheet metal strip to form apertures 28 at the holes 18,20, - a pair of pressing rollers 30 which at regular intervals within the stretched central web form a series of bosses or reliefs which displace the corresponding portion of stretched band into a plane which is slightly spaced from the plane of the web itself,

- a plurality of profiling rollers which transform the stretched strip into a C profile or a shelf. The continuous profile obtained in this manner is then cut transversely to size. Depending on the final result to be obtained, different methods can be provided; for example the starting expanded metal strip can be firstly subjected to a stage of slitting with simultaneous stretching followed by a profiling stage; or it can be subjected firstly to a slitting stage, then to profiling and finally to stretching; or to a single slitting, stretching and profiling stage. Pressing is carried out on termination of the profiling stage, although it can be done during passage through the profiling rollers or after stretching but before profiling. Instead of using pairs of rollers, the various operations can be carried out with presses or with presses and rollers. From the aforegoing it is apparent that the method of the invention presents numerous advantages, and in particular: - it eliminates any danger for the user as it forms holes with non-cutting edges,

- cables can be easily inserted as they encounter no friction with the hole edges,

- it eliminates any possible cracking because of the presence of previously formed holes in correspondence with the slits.

Claims

C L A I M S 1. A method for producing expanded metal profiles, consisting of subjecting a metal strip of width less than the development of the profile to be produced to the following operations: - forming longitudinal slits in at least that longitudinal band which is to form the central web of the profile,

- bending the edges of the slits,

- profiling said strip,

- transversely stretching that band containing the slits, - pressing areas of said central web in correspondence with said stretched band to displace them external to the plane of said web, characterised by previously forming holes in correspondence at least with the ends of the lines along which slits are to be formed.

2. A method as claimed in claim 1 , characterised in that the slitting stage takes place simultaneously with the bending stage.

3. A method as claimed in claim 1 , characterised in that the hole forming stage takes place simultaneously with the slitting stage.

4. A method as claimed in claim 1 , characterised in that after the bending stage, an edge drawing stage is effected.

5. A method as claimed in claim 1 , characterised in that the stretching stage precedes the drawing stage.

6. A method as claimed in claim 1 , characterised in that the profiling stage precedes the pressing stage.

7. A method as claimed in claim 4, characterised in that the bent edges are drawn to obtain radiused edging having the tangent to the free edge forming an angle not less than 90° to the surface of the strip.

8. A metal profile obtainable by the method claimed in one or more of claims 1 to 7, characterised in that at least one central web thereof presents at least one longitudinal band which is slitted, stretched transversely and provided with pressed areas (32) lying outside the plane of the web.

9. A metal profile as claimed in claim 8, characterised by having a C cross-section.

10. A metal profile as claimed in claim 8, characterised in that the slitted and stretched band presents burrs on the inner side of the profile.

11. A metal profile as claimed in claim 10, characterised in that said burrs present radiused edging having the tangent to the free edge forming an angle not less than 90° to the surface of the strip.