High-power density nut runners can now be 200 ft away from their controls without losing a signal, thanks to custom-made motion cables.
Designers at Ingersoll-Rand were redesigning their QE Series of tools when they found that no standard cabling could support 200-ft runs without losing power or digital signals data. So IR eventually turned to cable maker Leoni Elocab Ltd. in Ontario to custom build cables for its tools.
Leoni Elocab prototyped and te ste d a 12.9-mm cable for power and data. It had 17 wires instead of the standard 23: three twisted strands of awg 16 for power, 11 for data, and three spares. To eliminate EMI, the three wires carrying power had extra insulation and screening. “We wanted to keep the diameter small,” says Bill Ball, a senior electrical engineer at Ingersoll- Rand. Slim cables weigh less and are easier to handle.
The nut runner cable would be twice as long as previous cables and had to withstand more twisting and bending. So Leoni used chemically resistant polyurethane rather than polyvinyl chloride jacketing. It gives the cable a bending radius of five times the cable diameter. Leoni also used special tapes around the cores and conductors to make them flexible and durable. The inner wires were arranged to increase cable strength.
Endurance tests employed a 3-lb weight swung from one end of the cable. Cable specifications called for more durability, so Ingersoll-Rand engineers added a strain-relief connector between the cable and tool. With this external strain relief, the cable was still going strong after several million test spins.
Now Leoni also supplies Ingersoll with a slimmer hybrid design for a compact version of the QE tools. It has an outside diameter of just 7.6 mm, but carries four unshielded awg 20 conductors for power, and a fully shielded group of seven awg 28 data and control wires.