Title of Invention	METHOD FOR PRODUCING EXPANDED METAL PROFILES AND PROFILE PRODUCED BY THE METHOD
Abstract	There is disclosed 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 (12,14) in a longitudinal band which is to form the central web of the profile, - bending the edges of the slits, - profiling said strip, - transversely stretching the band containing the slits (12,14), - pressing areas of said central web in correspondence with said stretched band to displace them external to the plane of said web, wherein the bent edges of said stretched slits are subjected to drawing to obtain radiused edging having the tangent to the free edge forming an angle greater than 90° to the central web surface, said angle being measured between said tangent and said stretched slit; and expanded metal profile produced thereby.

Title of Invention

METHOD FOR PRODUCING EXPANDED METAL PROFILES AND PROFILE PRODUCED BY THE METHOD

Abstract

There is disclosed 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 (12,14) in a longitudinal band which is to form the central web of the profile, - bending the edges of the slits, - profiling said strip, - transversely stretching the band containing the slits (12,14), - pressing areas of said central web in correspondence with said stretched band to displace them external to the plane of said web, wherein the bent edges of said stretched slits are subjected to drawing to obtain radiused edging having the tangent to the free edge forming an angle greater than 90° to the central web surface, said angle being measured between said tangent and said stretched slit; and expanded metal profile produced thereby.

Full Text	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. The object of the present invention is to eliminate the above mentioned drawbacks. Accordingly, the present invention provides a method for producing expanded metal profiles, said method comprising subjecting a metal strip of width less than the development of the profile to be produced to the following operations: forming longitudinal slits in a longitudinal band which is to form the central web of the profile, bending the edges of the slits, profiling said strip, transversely stretching the 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; wherein he bent edges of said stretched slits are subjected to drawing, to obtain radiused edging having the tangent to the free edge forming an angle greater than 90° to the central web surface, said angle being measured between said tangent and said stretched slit. 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, ot 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. We Claim 1. A method for producing expanded metal profiles, said method comprising subjecting a metal strip of width less than the development of the profile to be produced to the following operations: forming longitudinal slits in a longitudinal band which is to form the central web of the profile, bending the edges of the slits, profiling said strip, transversely stretching the band containing the slits, pressing areas of said central web in correspondence with said stretched band to displace diem external to the plane of said web; wherein he bent edges of said stretched slits are subjected to drawing, to obtain radiused edging having the tangent to the free edge forming an angle greater than 90° to the central web surface, said angle being measured between said tangent and said stretched slit. 2. A method as claimed in claim 1, wherein the slitting stage takes place simultaneously with the bending stage. 3. A method as claimed in claim 1, wherein, before the slitting stage, a prior stage is carried out for forming holes in correspondence with the ends of the lines along which slits are to be formed. 4. A method as claimed in claim 3, wherein the hole forming stage takes place simultaneously with the slitting stage. 5. A method as claimed in claim 1, wherein the stretching stage precedes the drawing stage. 6. A method as claimed in claim 1, wherein the profiling stage precedes the pressing stage. 7. An expanded metal profile obtained by the method as claimed in any of claims 1 to 6, wherein the profile has substantially C shape cross-section, and the central web presents one longitudinal band which is provided with transversely stretched slits having radiused edgings which have the tangent to the free edge forming an angle greater than 90° to the central web surface of said profile, said angle being measured between said tangent and said stretched slit. There is disclosed 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 (12,14) in a longitudinal band which is to form the central web of the profile, - bending the edges of the slits, - profiling said strip, - transversely stretching the band containing the slits (12,14), - pressing areas of said central web in correspondence with said stretched band to displace them external to the plane of said web, wherein the bent edges of said stretched slits are subjected to drawing to obtain radiused edging having the tangent to the free edge forming an angle greater than 90° to the central web surface, said angle being measured between said tangent and said stretched slit; and expanded metal profile produced thereby.

Full Text

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.
The object of the present invention is to eliminate the above mentioned drawbacks.
Accordingly, the present invention provides a method for producing expanded metal profiles,
said method comprising subjecting a metal strip of width less than the development of the profile to
be produced to the following operations: forming longitudinal slits in a longitudinal band which
is to form the central web of the profile, bending the edges of the slits, profiling said strip,
transversely stretching the 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;
wherein he bent edges of said stretched slits are subjected to drawing, to obtain radiused
edging having the tangent to the free edge forming an angle greater than 90° to the central web
surface, said angle being measured between said tangent and said stretched slit.
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, ot 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.
We Claim
1. A method for producing expanded metal profiles, said method comprising subjecting a
metal strip of width less than the development of the profile to be produced to the
following operations:
forming longitudinal slits in a longitudinal band which is to form the central web of
the profile,
bending the edges of the slits,
profiling said strip,
transversely stretching the band containing the slits,
pressing areas of said central web in correspondence with said stretched band to
displace diem external to the plane of said web;
wherein he bent edges of said stretched slits are subjected to drawing, to obtain radiused
edging having the tangent to the free edge forming an angle greater than 90° to the central
web surface, said angle being measured between said tangent and said stretched slit.
2. A method as claimed in claim 1, wherein the slitting stage takes place simultaneously
with the bending stage.
3. A method as claimed in claim 1, wherein, before the slitting stage, a prior stage is
carried out for forming holes in correspondence with the ends of the lines along which
slits are to be formed.
4. A method as claimed in claim 3, wherein the hole forming stage takes place
simultaneously with the slitting stage.
5. A method as claimed in claim 1, wherein the stretching stage precedes the drawing
stage.
6. A method as claimed in claim 1, wherein the profiling stage precedes the pressing
stage.
7. An expanded metal profile obtained by the method as claimed in any of claims 1 to 6,
wherein the profile has substantially C shape cross-section, and the central web
presents one longitudinal band which is provided with transversely stretched slits
having radiused edgings which have the tangent to the free edge forming an angle
greater than 90° to the central web surface of said profile, said angle being measured
between said tangent and said stretched slit.

There is disclosed 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 (12,14) in a longitudinal band which is to form the central web of
the profile,
- bending the edges of the slits,
- profiling said strip,
- transversely stretching the band containing the slits (12,14),
- pressing areas of said central web in correspondence with said stretched band to displace
them external to the plane of said web,
wherein the bent edges of said stretched slits are subjected to drawing to obtain radiused
edging having the tangent to the free edge forming an angle greater than 90° to the central web
surface, said angle being measured between said tangent and said stretched slit; and expanded
metal profile produced thereby.

METHOD FOR PRODUCING EXPANDED METAL PROFILES AND PROFILE PRODUCED BY THE METHOD

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