Method and apparatus for covering a multiple wire conductor with a cross-linkable or vulcanizable insulation

Claim 1

In a method in which a conductor-separating tape combination comprising an electrical conductor having a plurality of wires which are covered with a longitudinally folded separating tape having circumferentially overlapped edge portions is covered with uncured insulating material by continuously advancing the combination through a transfer cavity of an extrusion head and by extruding the uncured insulating material over the combination as it leaves the downstream end of the transfer cavity, said edge portions tending to separate due to the resiliency of the tape material and said transfer cavity having an internal size greater than the exterior size of the combination so that the wall of the cavity is out of engagement with the folded tape, the further step of limiting the displacement of the overlapped edge portions of the folded tape with respect to each other to a pre-determined value during the travel of the combination through the transfer cavity in advance of the extrusion of the uncured insulating material by applying forces to the folded tape on the conductor as the combination travels through the transfer cavity, such forces being directed toward the tape and being of a magnitude sufficient to permit relative displacement of said edge portions of the tape which is not greater than said pre-determined value, said forces being applied by force applying means within the transfer cavity intermediate the wall of the cavity and the tape and being supported by the taped conductor and in contact with the tape but being unsecured to the wall of the transfer cavity so that the force applying means is free to move as a unit within the transfer cavity in the direction transversely of the direction of movement of said conductor through said transfer cavity.