Extrusion head with channels for producing inserts in a profiled band for manufacturing a pneumatic tire and corresponding extrusion method

The method for the coextrusion of a complex profiled element made up of the assembly of profiled elements formed from distinct rubber compounds. A coextrusion machine comprises upstream and downstream extruders which deliver into an extrusion cavity. A first profiled element, formed of the first rubber compound, is created. The first profiled element comprises at least a first profiled-element portion which is intended to form a longitudinal insert, a base of which is in continuity of material with the first profiled element. A complex profiled element formed of the first and second rubber compounds is created. The insert is circulated between walls of a channel extend in a longitudinal direction between the upstream profiling blade and the downstream profiling blade and together form a concave surface open towards the inside of the extrusion cavity in such a way that the bringing-together of the lateral walls of the insert with the second compound takes place only in the downstream gap.