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In 2004, North American
sales jumped 30% to 40% over 2003, says Frank Manfredi of Manfredi
& Associates, industry analysts. The surge was fueled by general
economic growth and increased sales to rental yards, which purchase
a large percentage of these big trucks.
In terms of unit sales,
manufacturers shipped 2,300 to 2,400 “artics” to North
American buyers last year, says Caterpillar. The previous high sales
figure was about 2,000 units, reached in 1998. Indeed, says Manfredi,
all manufacturers have struggled to keep pace with demand since
last year.
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PHOTO: Caterpillar |
To bring you the news
of artics, we at Grading & Excavation Contractor visited ConExpo-Con/Agg,
held in March in Las Vegas. “You’re seeing more and more
contractors go to articulated trucks because they can work all year-round
in the northern parts of the country,” says Caterpillar’s
Michael J. Kennamann, market consultant for artics. “They’re
being used for everything from shopping centers to overburden removal
in quarries to road construction.”
At Volvo Construction
Equipment North America, officials look for the boom in artics to
continue through this year, says Buddy Goodman, product marketing
manager for artics. He has observed new uses for artics firsthand.
“I know of one contractor in California who used an artic to
haul wet concrete to the paver,” Goodman says. “He had
a fleet of A40 trucks.” Other unusual uses for Volvo artics
include
- removing the body,
mounting a fifth wheel, and using the artic to pull bottom-dump
trailers;
- hauling lead ore
in underground mines in Missouri;
- replacing the body
with a large tree spade;
- replacing the body
with a large solid waste container; and
- mounting a drill
rig behind the tractor.
New Introductions
At ConExpo this year, Case introduced two new models of artics,
the 335 and 340, with rated operating loads of 35 and 40 tons, respectively.
Since the first two models were introduced at ConExpo three years
ago, Case says it has sold “close to 100 units” in Florida.
Marketing Manager Dave
Wolf points out that Case’s artics have no externally mounted
dumping cylinders. Instead, the trucks have a wider rear frame,
and the lift cylinders are mounted in-board, directly under the
body.
That provides several
advantages, says Wolf. The wider bed lowers the center of gravity
for more stability, and the hydraulic cylinders don’t get damaged
if and when the body rolls over. Moreover, the bed’s lift cylinders
don’t get mud thrown onto them.
And Case designed the
artic with the rear walking beam mounted to the bottom of the frame,
not cantilevered off the side. The result is a stronger structure,
Wolf says. The Case artic has limited slip axles throughout the
machine; power automatically transfers from the wheels that are
slipping to the wheels that are gripping.
Case’s artic models
325 and 330, the 25- and 30-ton units, have Cummins engines. The
larger two models are powered by Iveco engines. All models have
ZF automatic transmissions. You can shift the trucks manually, though;
a button on the shift lever toggles you between automatic and manual.
All trucks have six forward and three reverse gears.
Designed to be service-friendly,
all Case artics have a Lincoln automatic greasing system that serves
all lube points. All machines have a flip-forward hood and fenders
that swing out 90 degrees and give you access to valves and transmission.
On the larger two models, the cab tilts from right to left for access
to the powertrain.
“On the 335 and
340 we have an LCD display backed up by a system that automatically
checks all your fluid levels,” says Wolf. “Plus, you can
retrieve maintenance and diagnostic information at that display
in the cab. And it gives you a whole range of operating parameters,
such as how many hours you spent in first gear, second gear, and
so forth.”
The Case 335 and 340
models feature a dump brake. If you’re dumping the truck on
an incline, you activate the dump brake and it will hold the truck
in place. By shifting into forward, the dump brake is released.
On the 330, the engine brake is standard, and a transmission retarder
is optional. But the engine brake and transmission retarder are
standard on the 335 and 340, Wolf says.
New Ejector Model
At ConExpo in March, Caterpillar introduced its 730 Ejector
model. Instead of raising the bed to dump, the truck features a
sliding ejector that pushes material out of the bed. Material can
be spread and dumped on the go. Yes, the ejector adds about 6,000
pounds of weight to the truck and costs more, but Caterpillar’s
Kennamann says that reduced cycle times enable an owner to pay back
the cost premium in just two months’ use.
Ejecting a load without
raising the body improves stability, so the truck can work on inclines
and sideslopes and in soft underfoot conditions, Caterpillar says.
The truck also does well in tunneling and underground locations
and on sites where overhead obstacles, such as conveyors or power
lines, would interfere with raised-bed dumping. The reinforced ejector
body is made from high-yield, heat-treated steel. Its top rails
incorporate the same steel used on the Cat 769D off-highway truck.
Caterpillar offers a
full line of six artics, ranging from the Model 725 with 26 tons
of capacity to the 740 Ejector with 42 tons of capacity. Kennamann
says Caterpillar’s artics are heavier than the competition,
which he claims is an advantage in tough conditions. “We have
on-the-go differential locks, and we don’t get bogged down,”
he asserts. “Our wet clutch differentials can be engaged and
disengaged on the go.”
Caterpillar’s 730
Ejector truck features the Cat C11 engine with ACERT technology
to meet the EPA’s Tier 3 emission standards. The engine produces
317 net horsepower and boasts mechanically actuated electronic unit
injection. That system, together with air-to-air aftercooling and
single wastegate turbocharging, provides low emissions and responsive
performance.
The engine is matched
to a six-speed electronically controlled transmission featuring
an anti-hunt strategy and electronic clutch pressure control and
controlled throttle shifting for smooth shifts and extended component
life. The integral retarder offers high power density.
Low Operating Cost
Volvo says its trucks don’t have the lowest initial cost,
but do provide a low ownership and operating cost. The current D
series—which includes four units in the 25- to 40-ton class—was
introduced starting in 2000. Volvo’s Goodman says the company
consulted with customers when updating the line, and in addition
to productivity and low operating cost, customers wanted improved
serviceability.
“We pride ourselves
that it’s easy to remove an engine or transmission to rebuild
it, and easy to do daily maintenance,” says Goodman. “We
electronically monitor fluid levels. You don’t have to pull
dipsticks. When an operator starts up, the machine will tell you
if a fluid level is low, or even if one is over-full.”
Access to daily maintenance
points is a snap, Goodman points out. You don’t have to raise
the hood to change oil or fuel filters—you just lower the front
grille. Volvo provides a small removable hose that connects to the
oil drain under the engine.
“We have a system
called MATRIS—for Machine Analysis Tracking Information System,”
says Goodman. “It’s available on all of our large equipment.
We monitor all of the operating characteristics of the machine.
You can download the operating history—time spent in each gear,
the engine speed log over time, overspeed conditions, idle time
versus time in gear, retarder use versus brake use, and much more.
“We still use the
three-point suspension, but we improved the rubber spring in that
system,” continues Goodman. “It’s larger in diameter
and taller, and the shock absorbers were designed for the truck
itself. They’re not just regular truck shocks.”
Manufacturers often build
in retarders to save service brakes on articulated trucks. Volvo
is no exception, and builds an inclinometer into its artics. Posted
on the inside windshield is a decal that tells the operator what
gear and speed to use to negotiate the hill he is descending using
only the retarder and not the brakes.
Cooling fans automatically
activate based on cooling demand, which is determined and controlled
by the ECU, or electronic control unit. The cooling fans are not
engine-driven, so they don’t rob the engine of power.
Power-to-Weight
Deere offers four artic models in the 25- to 40-ton range.
All are made by Bell Equipment in South Africa. With horsepower
ratings ranging from 265 net horsepower in the 250D to 413 net horsepower
in the 400D, Deere’s four trucks boast power-to-weight ratios
that are among the best in the industry, says Neville Paynter, product
consultant.
“We try not to incorporate
a lot of heavy metal just for heavy metal’s sake,” says
Paynter. “You’ll see a lot of steel fabrication on our
trucks as opposed to cast iron. The articulation joint, for example,
is made of fabricated steel, not cast iron. The box is built of
ribbed steel for better stress rigidity than a straight steel plate.”
Deere’s power-to-weight
ratios keep the trucks going through the toughest conditions, Paynter
says. And the approach angle on the truck’s front—30 degrees
up from horizontal to the truck’s nose—is one of the sharpest
in the industry, which prevents the operator from ground contact
in uneven or hilly conditions.
Computerized controls
make the Deere artics easy to operate—and nearly abuse-proof,
says Paynter. When you switch on the differential lock, for example,
it only activates for 30 seconds, then switches off. That way if
the operator climbs onto a hard surface with the diff lock on, it
doesn’t tear up the differential.
The Deere artics have
five computer systems that all talk to each other. One controls
the engine, one controls the transmission, one is a hydraulic controller,
one controls the chassis, and one is an information center that
collects data to give technicians access to operating and fault
code information. “They all talk the CAN-BUS J1939 language,”
says Paynter.
The fault code information
is logged over time so a technician can tell how many times a particular
problem has been happening. If the problem is with the operator,
the technician can point that out.
Deere’s artics have
what Paynter calls the best retardation system in the industry.
Mounted on the output shaft of the transmission, the hydraulic retarder
is fully automatic, which ensures strong, safe slowdowns. “You
can operate this truck with very minimal use of the brakes,”
says Paynter.
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PHOTO: KOMATSU |
Different Suspension
Komatsu offers three articulated trucks ranging from a 30-ton
unit with 324 net horsepower to a 40-ton unit with 430 net horsepower.
“No other truck has the trailing arm suspension,” says
Steven J. Moore, product manager, trucks. “We’re the only
people that pull the front axle, and that gives us a better ride.
With the trailing arm suspension you get less shock transmitted
to the operator’s seat.”
Ride and traction are
improved by the hydro-pneumatic struts on both the front and back
of Komatsu’s trucks, Moore says. “Again, you’ve got
better control and better ride without a load,” he adds. “A
Komatsu will stick to the ground better without a load, and it also
gains better traction with a load.”
Moore emphasizes that
Komatsu trucks are built exclusively with integrated Komatsu components
backed by a heavy investment in research and development. “These
are all 100% Komatsu trucks,” says Moore. “These are not
kit trucks that are put together with an engine from one company
and a transmission from another,” says Moore. “Komatsu
has a huge commitment to R&D, understands the powertrain of
these trucks, and it shows.”
Other notable features
of Komatsu’s artics:
- A maintenance-free
center-oscillating hitch
- Higher horsepower ratings than competitors
- A smooth belly under the truck for easy flow-through of mud
- A low center of gravity
Komatsu trucks also boast
high top-end speeds, Moore says. Running on hard ground empty, the
35-ton truck can hit 35.4 mph; the 40-ton unit reaches 36.4 mph;
and the 30-tonner clocks in at 36.7 mph.
Terex’s Five
Models
Terex offers five models of articulated trucks, including units
with rated payloads of 25 tons, 27.5 tons, 30.9 tons, 35 tons, and
40 tons. The company says the three smaller models all feature
- high-power, high-torque,
emission-certified engines;
- automatic transmissions
with manual overrides;
- automatic limited
slip differentials in each axle; and
- a refined, quiet
cab for greater operator comfort.
The 35- and 40-ton models
have electronically managed, emission-certified engines, Terex says.
And the trucks boast 6 by 6 all-wheel drive with efficient ground-following
suspensions. Like the smaller models, the larger ones have automatic
slip differentials.
So the choices are many.
If you want a new artic this year, you’re well advised to order
quickly. Manfredi says most of the larger manufacturers had sold
their production for the year by mid-March.
Daniel C. Brown is
the owner of TechniComm, a communications business based in Des
Plaines, IL.
GEC
- July/August 2005
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