Design Challenge - June 2009

POPE DESIGN

“At last there is finally some serious talk in the USA about creating more renewable electricity on a grand scale. What has not been much talked about, however, is the need for transmission towers for these new sources of electricity. Badly needed upgrades on the existing outdated grid are just as important as the new additional electrical grid infrastructure.

Expanding and upgrading the US grid will be a huge challenge due to accessibility and working conditions. The RT Crane will be a big asset on this job for new construction and on repairing existing towers. The USA has some of the most diverse operating conditions you can get in any one country. With the exception of the flat central plains states, transmission lines run predominantly through somewhat rough terrain to extreme rough terrain. Most of these transmission lines are remote access only on unpaved roads and trails. Many are poorly kept. The RT Crane carbody will have to be able to carry the superstructure and boom through these challenging off-road conditions.

Its propulsion system was heavily influenced by Timberjack’s walking tree harvester, and the TreeHopper I designed for the cover of the 2007 iVT Off-Highway Annual. Walking legs are very well suited for steep hill climbs and water hazards, and retractable cleats on the feet could help traction in rougher conditions. Mechanical legs would help give the machine excellent weight distribution and low ground pressure, which would help to minimize erosion and improve traction on steep slopes. The mechanical leg articulations would be powered by radial linear motors. The legs would be fabricated from a lightweight aluminium closed box frame construction.

The only problem with articulating legs for propulsion would be during high-speed travel. Large, tight-jointed moving articulating legs could have violent consequences if anything large gets kicked up from the trail into the fast moving scissor-like legs. Debris on the side of a trail could also get caught up into the legs causing serious damage to the crane.

Some worksite locations can be several miles away from paved roads, so moving from worksite to worksite with a carbody only able to safely walk at 5mph is not an option. So the feet of this walking system have built-in track frames. The track system has individual one-piece cast track pads that are not connected to each other or use any bearings or bushings. This enables metal tracks to move at a rapid speed with no friction because there are no connected moving parts.

The track pads contain embedded rare-earth magnets. The track frame has a coil that is a band around the track frame in a continuous loop. Electric current flowing in one direction or the other pulls the track pads around the coil loop. Track pads never touch each other or the frame or coil while the tracks are moving. Because a continuous loop of track pads joined together to form a chain are not needed for this system to work, the track pads speed up on the top of the loop to cross one by one over the top half of the coil loop. Around 30% fewer track pads are needed for this system. This reduces the weight of the track assembly and the overall number of parts, and makes for fewer eventual replacement parts. Much longer part-life helps to reduce downtime and operating costs. This system could also be used for more conventional uses such as bulldozers and excavator carbodies.”

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BIOGRAPHY

I would have to say just about 100% of my Matchbox and Tonka toys were trucks and construction equipment. Basically I have been fascinated with heavy equipment for as long as I can remember.  I received a B.S. for Industrial design at University of Bridgeport and I have been an industrial designer for 15 years. The last 12 of those years have been specializing in heavy equipment. I have worked on projects for several different OEM’s while I was employed at Teague and later as a design consultant. I’ve had the pleasure to work on projects from a 400 ton dump truck to a powered wheelchair. I also have a bad habit of designing conceptual construction in my spare time.

CONTACT DETAILS

Email: contact@pope-design.net

Tel: +1 201 343 9065