Abstract: The present invention relates to an extruder head with a rotary die which requires no ball or roller bearings. A die and a mandrel rod consisting of a cable guide are fixed in a cylindrical axial bore of an intermediate rotary sleeve driven by a driving mechanism. The sleeve has a substantially cylindrical outer surface which slidingly revolves in the axial bore of a distributing cartridge. The gliding surfaces are lubrified by the hot synthetic material. A clamping nut axially maintains the intermediate sleeve and allows the leakage flow of the synthetic material to be controlled. Such an extruder head may be utilized for the fabrication of helicoidal elements of synthetic material, especially helicoidal rods for optical fibers.

Abstract: Apparatus for extruding a sheath of synthetic material around a conductor, comprising an extruder head with two inlet conduits respectively connected to two orifices traversed by the conductor, and distributor means for selectively connecting the inlet conduits to a first and second extruder, the distributor means including a distributor communicating with the two extruders and to a first and second inlet conduit of the extruder head, and means for control of the distributor, the distributor having a mobile member which includes at least one pair of direct channels respectively providing communication of the first extruder with the first inlet conduit and of the second extruder with the second inlet conduit in a predetermined position of the mobile member, and a pair of inverted channels respectively providing communication of the first extruder with the second inlet conduit and of the second extruder with the first inlet conduit in another position of the mobile member.