Industrie Pirelli Societa Per Azioni

Industrie Pirelli S.p.a.

Antonio Brovedan

Antonio Ferrentino

Angelo Sala

An extrusion head for extruding a plastomeric or elastomeric material on at least two filaments having a diameter of the order of 0.1 mm. and having a high modulus of elasticity while maintaining a constant spacing between the filaments and a process for such extrusion. The head comprises a mandrel with a cylindrical portion and a frusto-conical portion, the mandrel having grooves equal in number to the number of filaments extending along the surfaces of both portions for guiding the filaments. The frusto-conical portion has channels between the grooves for feeding the material between the filaments. A die with an opening having parallel walls for guiding the filaments and having a conical surface spaced from the frusto-conical portion is mounted adjacent the latter to provide a space for flow of the material. A further element adjacent the die may be used to extrude further material over the filaments embedded in the material extruded therebetween.

Process for extruding plastomeric or elastomeric material on filaments

Apparatus for laying-up fine filaments, i.e. filaments which may be readily broken by bending, tension or torsion stresses, which comprises a rotatable platform carrying a plurality of filament bobbins, each bobbin being supported on the platform so that it can rotate about its own axis and about an axis perpendicular thereto, a drive system for rotating the bobbins about the latter axis as the platform is rotated to produce one rotation of each bobbin about the latter axis with each revolution of the platform, braking means for the bobbins which varies the braking force in accordance with radius of a filament winding on a bobbin, tubular guides extending between each bobbin and the laying-up point and supporting discs intermediate the bobbins and the laying-up point which are rotatable with the platform, the tubular guides being rotatably supported on the discs.

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Milan, Italy

Antonio Brovedan