Traditionally a builder of truck tanks and trailers for hauling liquid asphalt, the E D Etnyre & Company is building lowbed trailers at its plant complex in Oregon, Illinois.
The lowbed trailers are built by the Etnyre Trailer Company, a subsidiary of E D Etnyre. Etnyre named its lowbed trailer the Blackhawk and designed it to be mass-produced.
A Blackhawk prototype trailer was built in 1994, and full production began in 1995, says William Staddon, sales and product manager at Etnyre Trailer Company.
Blackhawk lowbed trailers are available in 35-, 50-, and 60-ton capacities and have up to 26-ft decks.
Etnyre uses a lot of fixturing for consistency because the Blackhawk was designed to be a production-oriented trailer, Staddon says. Before starting full-scale production of the Blackhawk, the company began enhancing its labor processes to make it cost competitive in the marketplace.
"Etnyre knows exactly what it costs to build a Blackhawk trailer and reduced that cost more than 10% through the use of welding fixtures and design enhancements," Staddon says.
Cylindrical Welding Fixture The Blackhawk lowbed trailer is built using highly-engineered welding fixtures, robotic welders, and other automated equipment. Much of the assembly takes place on a large, cylinder-shaped turning fixture that holds the trailer frame and rotates 360 degrees so all welds can be made in the flat position.
A series of large rings form the cylinder and hold the trailer in place. The top half of fixture rings are lifted off by hydraulic cylinders, and the trailer frame is moved by an overhead crane.
Rings on the end of the cylinder each have two electric motors, and the center ring has another electric motor. Sprockets driven by the motors fit in holes on the rings to rotate the fixture.
Before the frame is moved into the cylinder, the rear section is tack welded. Inside the fixture, crossmembers are inserted through cutouts in the two center beams.
Another welding fixture for the main deck on the custom lowbed platforms has 50 hydraulic cylinders that hold pieces in place for welding.
When fabricating trailer components, Etnyre uses equipment designed for speed and consistency. An automatic beam welder welds all four trailer beams, and a plasma cutting table cuts all raw material up to an inch thick.
Metal sheet on the table is cut using a new nesting software, says Gary Sasscer, manufacturing engineering manager. The nesting software used by the table controller maximizes sheet usage and allows parts to be cut for different products from the same sheet.
"Previously, parts were nested manually and it depended on the skill of the operator," Sasscer says. "Using the new software is much faster." Heavily Fixtured Plant
Etnyre's plant is heavily fixtured to build other trailers in addition to the Blackhawk lowbed. A clamshell-type fixture using hydraulic cylinders positions and pulls rings tight for welding against the outer shell of tank trailers. Each of the welding fixtures are built by Etnyre.
Goosenecks for lowbed trailers are welded in a fixture with a squeeze die that pulls the flanges against the web for tack welding. The fixture has interchangeable dies for goosenecks built for different models of Blackhawk trailers.
Beams for goosenecks and the rear section of the trailer are built in a recently installed robotic welding cell. The same robotic arm welds on two indexing tables. One table can be loaded with parts while the workpiece on the other table is welded.
After finish welding in the cylindrical fixture, the trailer is removed for installation of the axles and suspension. The running gear is aligned to the rear section in the fixture to provide accurate axle tracking.
Next the trailers are sandblasted, primed, and painted in a 25,000-sq-ft paint shop. Lights, wiring, and hydraulic and pneumatic lines are installed in a 7,200-sq-ft finish shop. Blackhawk lowbed trailers and asphalt transport tanks are built in Plant B, which accounts for over 90,000 sq ft of Etnyre's production complex.
Trailer Design Improvements Since it began building lowbed trailers, Etnyre has made several design changes, Staddon says. In some areas on the Blackhawk, the amount of steel was reduced because of the use of higher-yield material.
"We're using less material to do the same job," he says.
The design changes are based on finite element analysis, Staddon says. Each change is subjected to strain-gauge testing before being included in trailer design and production.
A change was made to crossmembers in the rear section that provide a trough for a boom on an excavator. The crossmembers have a five-inch recession to assist in lowering the overall height of the excavator.
Another design modification was made for lowbeds that only use beams for a deck, Sasscer says. Flanges are thicker and wider since only two beams are used instead of four on a regular deck trailer.
"We're constantly looking at design changes and better ways to build our trailers," Staddon says.
Diversified Product Line Blackhawk lowbed platforms and asphalt tanks are built in the same plant. In adjacent plants, other equipment is built for the transportation and computer controlled application of liquid asphalt.
Chip spreaders used for the chip-sealing process are assembled on an automated line in a 12,800-sq-ft building adjacent to the trailer plant. Components and parts for chip spreaders are fabricated in Plant A, which is 30,000 square feet.
Since 1898, Etnyre has been known for building tanks that spray liquid asphalt on roadways for road construction and maintenance. When the company started over 100 years ago, the tanks were considerably smaller and pulled by horses.
Today, most of the asphalt distribution tanks are about 2,000 gallons up to 5,000 gallons and are mounted on trucks with spraybars.
Many of the asphalt transports are tandem-axle trailers. Etnyre builds tanks that can haul up to 13,000 gallons on eight axles. The asphalt is transported at temperatures from 160 degrees up to 425 degrees Fahrenheit in the insulated tanks, which maintain the temperature.
Asphalt Tank Trailers Because of the high temperature and weight of these products, the tank trailers that transport them have special design features.
To accommodate dimensional changes in the tank barrel caused by temperature variation in the product, tank bolsters over the suspension subframe have slip joints, says Tom Brown, senior vice-president of Etnyre Trailer Company. Three bolsters support the tank on the suspension subframe.
Only one of the bolsters is fixed to the subframe, and the other two slide on the bogie, he says. The tank trailer barrel is constrained laterally and vertically by the fixed bolster, but can move longitudinally.
In a 48-ft trailer that hauls molten asphalt, a 350 degree temperature change will cause the length of an aluminum barrel to expand or contract up to three inches, Brown says. The length of a steel barrel will expand and contract up to 1 1/8 inches.
The temperature change happens quickly because the trailers are loaded in refineries at more than 1,000 gallons per minute. To withstand this harsh use, the trailers are built to the structural equivalent of a DOT 406 code tank but are noncode tanks.
Construction Equipment Dealers The bituminous distributor truck-mounted tanks are sold through Etnyre's distributor network. But the Blackhawk is sold by construction equipment dealers. The bituminous transport units are sold directly by national account managers.
Blackhawks are sold by construction equipment dealers for Caterpillar, Hitachi, Komatsu, Kobelco, and John Deere. Most of the trailers are purchased by construction equipment companies for hauling equipment such as earth movers, backhoes, excavators, and road graders.
In the United States, there are up to 90,000 construction contractors, Staddon says. Etnyre has aimed its distribution of the Blackhawk lowbed trailer at this market.
Staddon says it is difficult to determine the exact size of this market, but he believes that up to 6,000 lowbed trailers with capacities over 40 tons are built each year.
"In the lowbed business, nobody knew who we were," Staddon says. "So we wanted a trailer everyone would know."