Shielded cable

Claim 1

An elongated shielded cable having a longitudinally extending axis and a substantially circular cross section taken at right angles to said axis, said cable comprising at least three elongated conductors each having an individual inner sheath of insulation, each of said inner sheaths being of generally circular cross section, said elongated conductors being disposed in a group immediately adjacent each other in a symmetrical relationship about said longitudinal axis, said sheaths of said elongated conductors being in contact and defining a longitudinally extending empty space in said cable at said longitudinally extending axis, a flexible, conductive foil shield surrounding said group of conductors and extending along the length thereof, said conductive shield having its longitudinal edges overlapped in a manner providing a single shorted turn about the enclosed conductors, said conductive shield being formed to follow substantially the outer contour of said sheaths of said group of conductors and thus having a plurality of elongated recesses distributed symmetrically about its outer surface, a plurality of drain wires extending along the outer surface of said conductive shield in contact therewith, the number of drain wires being equal to the number of recesses, each recess having one of said drain wires lying therein and extending therewith, said drain wires being held by said foil shield against inward movement toward said empty space at said longitudinally extending axis to prevent said conductors from separating and to prevent a capacitance unbalance, an outer extruded sheath of insulating material surrounding said drain wires and extending partially into said recesses and about said drain wires and holding said drain wires in contact with said shield, said drain wires substantially filling said recesses and providing a more relatively uniform cross sectional thickness for said shield and a rounded cross section for said cable.