Forming sealed seams in moisture barriers for cable

摘要

In the manufacture of a communications cable, a moisture barrier comprising a corrugated metallic tape having inwardly and outwardly facing major surfaces is wrapped longitudinally about an advancing cable core to form an overlapping seam, with at least a portion of each of the major surfaces which form the seam being precoated with an adhesive copolymer material. Heat is applied to at least the portions of the moisture barrier which form the seam while the portions are spaced apart a distance sufficient to permit a stripe of adhesive copolymer material in molten form to be introduced into engagement with a longitudinal edge portion of the precoated outwardly facing surface which is destined to form the seam and which is disposed generally horizontally. Then the cable core and moisture barrier are advanced between coacting rollers which apply forces to the moisture barrier to cause the spaced apart portions to engage each other with the stripe engaging the precoated longitudinal edge portion of the inwardly facing surface which forms the seam and filling the spaces between associated corrugations to form an essentially continuously sealed seam. A longitudinally extending mandrel supports the barrier during the application of the forces to preserve the configuration of the enclosed core and to prevent damage to the core or the moisture barrier.