Multiple channel duct manifold system for fiber optic cables

Claim 1

A multiple channel duct for optical fiber cable comprising: a plurality of contiguous, co-directionally extending, substantially parallel sections of elongated, tubular corrugated conduit in abutting contact with each other, each of said sections having a series of encircling contiguous convolutions extending over the length thereof to impart flexibility to the respective elongated conduit sections, said convolutions being made up of contiguous ridges and troughs whereby the frictional resistance to the pulling of optical fibers therethrough is substantially reduced, and the resistance of said sections to longitudinal sliding movement against each other is substantially increased; and a flexible, synthetic resin overwrap sheath consisting of a sheath of rigid polyvinylchloride having a thickness of about 5 mils to about 15 mils, said sheath of rigid polyvinylchloride encircling and jacketing the corrugated conduit sections over their entire length to retain them in their contiguous relationship, said sheath having sufficient strength and flexibility to permit said conduit sections to undergo flexing without any substantial restriction of, or reduction in, the extent of flexibility of said sections resulting from encircling them with said sheath, and said sheath maintaining its physical integrity without parting or fracturing as said conduit sections undergo bending through a small radius of curvature.