Western Electric Company, Inc.

George F Piper

William C Vesperman

Max K Wilson

William M Kanotz

William Robert Lockhart

In the manufacture of cordage (25), at least two groups (28, 29) of individually insulated, flexible conductors (21--21) which comprise a planar array (40) are moved through a core tube (71) of an extruder (27) in adjacent paths. As the groups are moved out of an exit portion of the core tube where they are spaced apart a predetermined distance and along converging paths to a die, a first plastic material is flowed about the array to enclose it and to be formed into a jacket by the die. Portions of the first plastic material flow between the groups to achieve an equilibration of pressure in the plastic material about each group, which controls the direction and magnitude of lateral movement of each group within the plane of the array, and to form a web (41) which is integral with the jacket and which may vary in thickness along its length to compensate for changes in the outside diameter of the insulated conductors. The control of the lateral movement of each group between the core tube and the die and the formation of a web results in a jacket having substantial symmetry and in cordage having the groups separated by the web which has a thickness that is substantially less than the predetermined distance. The jacket is coated with a second plastic material which has a stiffness modulus that is substantially greater than that of the first plastic material.

Cordage having a plurality of conductors in a partitioned jacket

Methods of enclosing a plurality of conductors in a partitioned jacket

Apparatus for enclosing a plurality of conductors in a partitioned jacket

An insulation comprising a polyether polyester thermoplastic copolymer obtained by reacting 1,4 butane diol terephthalate with terephthalate esters of polytetramethylene glycol is coated over an irregularly configured conductor, such as for example, a tinsel conductor, suitable for use in telecommunications cordage by moving the copolymer through an extruder and along a flow path formed between a core tube and wall of a die cavity. The die cavity adjacent to the throat of the die has a frustoconical portion formed with an approach angle of sufficient magnitude to minimize the pressure drop through the extruder to extrude the copolymer at a temperature slightly above the melting point of the copolymer. The copolymer is insulation tubed over the tinsel conductor with a gas at a controlled volume rate of flow being moved through the core tube along with the tinsel conductor to expand the copolymer extrudate as it flows out of the die opening to cool the extrudate and to facilitate advantageously oriented crystalline growth of the copolymer. Subsequently, the insulation is drawn down about the tinsel conductor with a slight spacing therefrom while treating the insulation with water at a predetermined temperature to anneal the insulation in a predetermined manner. A plurality of the insulated tinsel conductors are enclosed in a jacket which comprises a plasticized polyvinyl chloride composition.

Apparatus for insulating flexible conductors

An insulation comprising a polyether polyester thermoplastic copolymer obtained by reacting 1, 4 butane diol terephthalate with terepthalate esters of polytetramethylene glycol is coated over an irregularly configured conductor, such as for example, a tinsel conductor, suitable for use in telecommunications cordage by moving the copolymer through an extruder and along a flow path formed between a core tube and wall of a die cavity. The die cavity adjacent to the throat of the die has a frustoconical portion formed with an approach angle of sufficient magnitude to minimize the pressure drop through the extruder to extrude the copolymer at a temperature slightly above the melting point of the copolymer. The copolymer insulation is tubed over the tinsel conductor with a gas at a controlled volume rate of flow being moved through the core tube along with the tinsel conductor to expand the copolymer extrudate as it flows out of the die opening to cool the extrudate and to facilitate advantageously oriented crystalline growth of the copolymer. Subsequently, the insulation is drawn down about the tinsel conductor with a slight spacing therefrom while treating the insulation with water at a predetermined temperature to anneal the insulation in a predetermined manner. A plurality of the insulated tinsel conductors are enclosed in a jacket which comprises a plasticized polyvinyl chloride composition.

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Baltimore, MD, United States of America

George F Piper