Group twinner for single and double conductor bobbins and method of making communication cables

Abstract

An apparatus is disclosed for manufacturing communication cables with improved, more uniform impedance characteristics at signal frequencies up to and above 600 MHz. The apparatus includes an “inside-out” rigid twisting machine and at least two bobbins supported within each such machine. Each rigid twisting machine includes a drive for spinning each of the bobbins about their respective axes, and fly-off arrangement is provided for flying off an insulated conductor wire wound on each of the bobbins with substantially no tension in the wire when the bobbin attains a first rotational speed. Guides are provided for guiding the wires from each of the bobbins to a closing point where the wires are closed. A double twist bow arrangement is provided which includes second drive for twisting the closed wires at a second rotational speed to form a twinned cable. Controls are provided for adjusting the first and second rotational speeds to apply a pre-twist to each of the wires about their individual neutral axes prior to twinning, after which a take-up is provided for taking up the twin cable. A bank or line of rigid twisting machines are preferably used to produce two or more twinned cables, which all can then be twinned or twisted about each other to form a multi-cable assembly. An alternate embodiment uses a single bobbin wound with a pair of conductor wires that are flown off together and twisted about each other, resulting in a machine with a smaller footprint and bow and higher speeds of operation.