Abstract: The invention relates to the formation of a metallic shield about a cable core to provide a substantially circular configuration of the shield around the core with an overlapped edge portion of the shield being preformed. The shield is first partially formed about the cable core and thereafter the shield is formed in the substantially circular configuration around the cable core while a portion of the overlying longitudinal edge portion of the shield at the overlap is turned inwardly toward the cable core sufficiently to preclude the edge portion of the shield from protruding disadvantageously into a jacket which is subsequently extruded over the shielded cable core.

Abstract: A plurality of groups of mandrels are arranged for movement successively through a plurality of workstations with each group being worked on at a station while other groups are being worked on simultaneously at other stations to produce continuously automatically groups of retractile cords. Cordage is fed from a supply into clamping engagement with each of the mandrels in the group in a cord-loading position and then wound helically in a plurality of spaced-apart convolutions on each of the mandrels of that group after which the wound cords are severed from the cordage supplies. The wound cords are advanced incrementally through a heating zone, wherein the cords are exposed to radiant heating supplemented by preheating of the mandrels, while cordage is being wound on the next successive groups of mandrels.

Abstract: A cable core, the interstitial spaces within which are being filled with waterproofing compound in a semi-fluid state as it passes through a compound-applying or filling chamber into which the compound is introduced under pressure, is advanced through a wiping die in a constricted passageway and into another chamber into which similar compound is pumped. The compound in the second chamber is at a substantially lower temperature than the compound in the filling chamber and exerts pressure radially on the cable core being filled to form a sheath or coating of the lower temperature compound around the filled core to seal the first compound in the core. The core is thereafter passed through a sizing die into a cooling chamber which solidifies the compound in and around the core. The cable core is thus conditioned for the subsequent application of sheathing materials thereto, for example, core wrapping and/or armor sheathing.

Abstract: A plurality of groups of mandrels are arranged for movement successively through a plurality of workstations with each group being worked on at a station while other groups are being worked on simultaneously at other stations to produce continuously automatically groups of retractile cords. Cordage is fed from a supply into clamping engagement with each of the mandrels in the group in a cord-loading position and then wound in a plurality of spaced-apart convolutions on each of the mandrels of that group after which the wound cords are severed from the cordage supplies. The wound cords are advanced incrementally through a heating zone, wherein the cords are exposed to radiant heating supplemented by preheating of the mandrels while cordage is being wound on the next successive groups of mandrels.

Abstract: Flow conditions in an extrusion head in a cross head type extrusion apparatus for applying a concentric plastic insulating covering uniformly around a longitudinally advancing filamentary core advancing axially through a die concentrically disposed in an extrusion chamber in the head, are improved by providing channeled tooling within the chamber which bends and divides an initial stream of plastic material forced into the chamber into a plurality of equal streams which combine symmetrically around the core. With respect to certain channels, the ratio of the length of the channel to its effective cross-sectional diameter exceeds a predetermined critical number to achieve the development of steady state fluid flow therein.

Abstract: First and second concentric insulating sheaths of plastic materials are formed continuously around a filamentary core advancing longitudinally through an extrusion chamber. The core is passed axially through a tapered entrance portion and a coaxially aligned tapered throat portion formed in a separable die disposed in the chamber. Fluent plastic material for the first sheath is delivered from a main extrusion bore, impinging on the core circumferentially at the entrance portion of the die, the flow thereof being developed as it passes into the throat portion thereof. Fluent plastic material for the second sheath is delivered from an auxiliary extrusion bore flowing through a plurality of dividing channels formed in the die and radially inward at a plurality of circumferentially spaced points around the die axis into an annular manifold or reservoir where the fluid pressure of the plastic achieves a steady state condition.