METHOD FOR SEAMING T PROFILES, APPARATUS FOR IMPLEMENTING THE METHOD, AND PROFILE OBTAINED BY THE METHOD

The present invention relates to a method for seaming T profiles, an apparatus for implementing the method, and a profile obtained by the method. T profiles obtained by profiling a sheet metal strip are known for forming support frames for false ceilings.

To ensure substantial rigidity for the profile web, this is provided with a plurality of longitudinal seams obtained by a process comprising a first step in which a plurality of parallel slits of length L are formed in said web spaced apart by a width H, after which a transverse punching operation is effected with a punch having the same length L and width H against a die provided in a wheel facing the punching wheel.

These known profiles have however proved susceptible to improvement with regard to the flexural rigidity of the profile. According to the invention, this improvement is obtained by a method for producing profiles, as described in claim 1.

A preferred embodiment of the present invention is further clarified hereinafter with reference to the accompanying drawings, in which: Figure 1 is a plan view of the punching machine for effecting the seaming, Figure 2 is a side view thereof,

Figure 3 is a section through the first punching wheel during the punching of the sheet metal strip,

Figure 4 is a section through the second punching wheel during punching, Figure 5 is a side view of a T profile comprising a plurality of seams, Figure 6 is a cross-section therethrough on the line Vl-Vl of Figure 5, and Figure 7 is a longitudinal section therethrough on the line VII-VII of Figure 5.

As can be seen from the figures, the method of the invention uses two pairs of punching wheels 2, 2', 4, 4' of vertical axis, the wheels 2, 4 being provided on their lateral surface with two rows of first punches 6 and second punches 8 which are faced on the wheels 2', 4' by two annular grooves 10, 12. The annular groove 10 is a through groove whereas the groove 12 has a width slightly greater than the first groove and a depth such as to form a die for the second punches 8 of the wheel 4.

The first punches 6 have a substantially trapezoidal longitudinal section whereas the second punches 8 have a substantially rectangular section with the major side L' having a dimension greater than that of the first punches 6 and comprising a semicircular seat 14.

With the method of the invention, when the sheet metal strip has passed through the profiling machine and the T profile 14 has been obtained, the web 16 of this is made to pass through the pairs of punching wheels 2, 2' and 4. 4'. As a result of this passage, the first punches 6 form on the web of the strip a plurality of pairs of parallel incisions having a length corresponding to the length of the first punches 6 and spaced apart by a distance corresponding to the thickness of the first punches.

The web 16 is then subjected to the action of the second punches 8 which effect a further punching in correspondence with the first punching. As already stated, as these punches 8 have a length greater than the punches 6 of the first punching wheel, the sheet metal cannot further translate because of the presence of the die formed by the groove 12, but instead the most outer portion forms a kind of collar 20 which embraces the inner portion to hence prevent longitudinal

slippage of the two parallel parts facing the webs and thus provide greater flexural rigidity.