Roadtrain remedy

IN RESPONSE TO a customer's request for a new roadtrain combination, Brazilian company Recrusul SA has developed a smaller-size fifthwheel for the dollies used in the new nine-axle road trains that are allowed in certain areas of Brazil.

The goal for Recrusal SA — one of the largest trailer manufacturers in Brazil — was to achieve a low tare weight, vertical load capacity of the coupling (which allows axle lifting on the dolly), less maintenance, better stability for the dolly and rear semi-trailer, greater angles between front semi-trailer and dolly, easy access for tank unloading, cleanliness in the discharge area, easy-to-find components subject to wear, and a lower overall cost.

Paulo de AB Gomes, director of sales engineering, says the company achieved a 198 lb weight reduction (only with the fifthwheel) and a 50% cost saving, and it also became possible to have a first axle lift on the dolly. The coupling accepts radial loads of up to 11,000 lb, it can pull loads up to 81,750 lb, the components subject to wear are market standard, trailer sway is reduced as well as general maintenance, and turning radius/vertical movement (+/- 11°) have also improved.

Located 16 miles from one of Brazil's major port cities, Porto Alegre, Recrusul has established itself particularly in the areas of refrigerated, liquid, and dry-bulk transportation. The company produces its own refrigeration units, bus air-conditioning, and refrigeration equipment for refrigerated warehouses. It also is a major manufacturer of refrigerated trailers and truck bodies.

The latest project started when Recrusul received an order from Rodoviário Morada do Sol in Araraquara, 187 miles from São Paulo, the industrial and center of Brazil.

Rodoviário Morada do Sol, a transport company that specializes in the transportation of orange juice for the major Brazilian industries, has more than 200 insulated tank trailers operating around the clock. They carry 31 tons of payload each, delivering the low-temperature juice to the tank farms located in the port of Santos. The trip lasts around eight hours, and requires a time-consuming navigation through the downtown area of São Paulo, a city of 18 million people.

Change in legislation

Due to recent change in local legislation, road trains (6×4 tractor, semi-trailer, dolly, and semi-trailer for a total of nine axles) received permission to run in the Imigrantes Highway, a 60-mile downhill road from São Paulo to Santos — as long as the combination keeps its total length between 82 and 85 feet.

The purpose was to avoid load concentration on bridges and pavement and yet be an easy-to-maneuver transport unit. The maximum gross weight is 74 tonnes (163,140 lb), plus an allowance of 5% (payload of around 119,048 lb).

With this in mind, Rodoviário Morada do Sol asked Recrusul to develop a new road-train combination, as well as studying the possibility of converting old units into road trains.

“Our former experiences in developing those vehicles, always bumped on an Achilles Heel — the coupling of the dolly-type trailer with the front semi-trailer,” Gomes says. “The problems of such couplings are basically too much maintenance, low capacity for radial loads, exaggerated rear trailer sway, interference with rear discharge piping, and limited turning radius capacity.

“Those facts led us to start thinking on a new proposition to couple the units. We saw road trains using standard fifthwheels assembled on the rear of the front semi-trailer, and dollies with kingpins on its front end. The idea is very good, but as our customer demanded interchangeability between both semi-trailers, we would have to use two fifthwheels at the rear of both semi-trailers, and this meant too much weight and cost.

“Besides, the standard fifthwheel is too heavy — around 353 lb each — and bulky, which is a big problem to install in a place where it is necessary to connect a 6" insulated discharge hose with quick coupling.

“Another issue we had to consider is the fact that the semi-trailer carries edible products, so the discharge area must be as clean as possible, so a greasy coupling is not recommended. Then we had the idea to develop a small fifthwheel, in some way similar to the ones manufactured in Europe for full trailers, and instead of assembling it at the semi-trailer's rear, we decided to assemble at the front end of the dolly, in an upside-down position, to couple with a standard kingpin, also upside down, at the rear end of the semi-trailer, very much the same as the hooks used on passenger cars to pull lightweight trailers — a quite unusual assembly for heavy semi-trailers.”

Recrusul checked all advantages and disadvantages of such a system, and started to develop a homemade, lightweight fifthwheel.

It has received a patent-pending status in Brazil, and also has another order for the equipment.

He says running gears are INTRAAX with wide-base tires on aluminum wheels, 11.75" × 22.5". Frames are made of high-tensile weldable steel. Tanks are stainless steel 304 self-supporting, insulated with 4.5 inches of polyurethane foamed in place and jacketed with glass-reinforced plastic sheets.

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