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First introduced several
years ago by Takeuchi and ASV Inc., today rubber-track loaders also
are offered by Bobcat, Gehl, and Caterpillar. And New Holland says
it is testing and reviewing types of tracks.
"Compact track loaders
are fairly common in Europe, and they're becoming more popular in
the United States," says Industry Analyst Frank Manfredi of Manfredi
& Associates. "Takeuchi was one of the original companies to
sell a tracked loader, and then about 10 years ago ASV was formed.
They developed a rubber-track undercarriage and supply it to both
Caterpillar and Polaris."
At Takeuchi, Mike Ross
says track loaders are a very big growth market in the US. "I think
the rubber-track-loader market has grown by 35 a year for the past
four years. A lot of people who have been running skid-steers are
going to these machines. They're finding out that a track machine
is a lot more productive." One equipment dealer notes that a compact
track loader can replace a small dozer - and is smaller to transport
in the bargain. Takeuchi offers three models of rubber-track loaders
that range up to 81 hp with a turbocharger.
It's true that track
machines are more expensive than skid-steers, says Ross - about
$8,000ñ$10,000 more for the same-size machine. "But most operators
find that [track-loader] productivity is about double that of a
skid-steer. And these track machines are a lot more versatile."
For example, a track
loader offers flotation; it can work in muddy areas where a skid-steer
can't go, says Bobcat's Lance Schulz. Plus, a track loader extends
the work season. In northern climates, you can work earlier in a
wet spring and later in the fall. "A track loader grades better
and has more pushing power than a skid-steer [does]," says Schulz.
Today, Bobcat offers four rubber-track models - two with radial-style
lifting linkages and two with vertical-lift linkages. Two of the
machines are rated at 56 hp, and two have 81 hp.
Gehl buys rubber-track
loaders from Takeuchi. "We have an agreement for them to build machines
for us," says Gehl's Kelly Moore. The company offers two track models,
one with 66 hp and the other with 97 hp. Both feature radial-style
lift arms and were introduced in March 2002.
At the same time, Caterpillar
introduced its 247 and 257 Multi Terrain Loaders, which feature
a rubber-track undercarriage from ASV, a Caterpillar affiliate.
Both of these machines use the upper portions of Cat skid-steer
loaders. The two machines have operating capacities, respectively,
of 1,354 lb. (the 247) and 1,614 lb. (the 257).
The company says the
new rubber-track undercarriage transfers weight to the ground through
24 wheeled contact points. The rubber track is lightweight and pliable
yet is reinforced with high-tensile-strength cords for extra durability.
Its edges are beveled to prevent scuffing or damage when used on
lawns or turf.
Caterpillar also offers
two larger models - the 267 and 277 rubber-track loaders. Like the
247 and 257, these models combine a skid-steer upper portion with
an undercarriage from ASV. The 267 and 277 have operating capacities
of 2,030 lb. and 2,065 lb. The Society of Automotive Engineers defines
operating capacity for a track loader as 35% of its maximum tipping
load. Wheeled loaders are rated at 50% of the tipping load.
ASV recently introduced
the RC-100, its newest rubber-track machine. The machine boasts
a 99.5-hp Cat engine, a 7,600-lb. tipping load, and a lift height
of 125 in. ASV says the Posi-Power Control system makes it virtually
impossible to stall the engine because the system automatically
shifts the hydrostatic drive to match available horsepower.
Skid-Steers Increase
Wheelbases
The recent trend in skid-steer
loaders is toward larger machines and those with longer wheelbases,
according to manufacturers. Longer wheelbases offer a smoother ride,
increased stability, and a greater load-carrying capacity. "We've
heard customers say they like the longer wheelbase," says Rusty
Schaefer at Case Construction Equipment.
With all other things
being equal, a longer wheelbase will scuff the tires more in a turn.
Traditionally, longer wheelbases produce more tire wear, but now,
says Schaefer, manufacturers are building tires that last longer.
"That allows us to increase the wheelbase without significantly
decreasing tire life."
If you hold the width
of a skid-steer loader constant, though, there's a limit to the
length of the wheelbase, says Bobcat's Lynn Roesler. "A machine
with a longer wheelbase can require a wider width between the tires
if you want to turn it very easily." Bobcat engineers look at the
tread width of the loader - the distance between the centerlines
of the right and left tires. Then the engineers consider the tread-widthñto-wheelbase
ratio.
"If that tread-widthñto-wheelbase
ratio were 1.0, the machine would turn hard; your wheelbase would
be much too long," explains Roesler. "It would be doggy in turning
and would require a lot of horsepower to turn the machine." He says
many Bobcat skid-steer loaders have a tread-widthñto-wheelbase ratio
of around 1.40. The company's top-selling skid-steer loaders, the
S175 and S185, have a 1.38 ratio of tread width to wheelbase. "The
lower that ratio is, the more power it will require to turn."
Skid-steers have the
ability to counter-rotate or spin about the center of the machine,
says John Deere's Larry Foster. "Thus, the wheelbase can be longer
or shorter, but the key dimensions that affect maneuverability are
length and width."
"It is worthy to note
that from the mid-'80s only John Deere and New Holland had long-wheelbase
machines," says Foster. "Today, however, every manufacturer has
long-wheelbase machines. In fact, from the 1,500-lb.-rated operating
capacity and up, all of the competitor machines have increased their
wheelbases to longer wheelbases like the Deere and New Holland models
[have].
"John Deere has an exceptionally
low center of gravity because we keep all of the heavy components
and fluids low in the frame," continues Foster. "The benefit is
superior stability and balance for enhanced load carrying, increased
traction, and more stable and safe operation on unlevel terrain."
For the record, the wheelbases on John Deere skid-steers range from
42.3 to 48.6 in.
While noting the advantages
of a longer wheelbase, Caterpillar points out that a longer wheelbase
can cause accelerated tire wear and require more horsepower to turn.
Wheelbases on Caterpillar skid-steers range from 39 to 48 in.
Pilot Controls?
If Caterpillar and John
Deere now offer pilot-actuated controls on their backhoe loaders,
is that feature available for skid-steer loaders? It's not a black-and-white
issue, but such hand controls generally provide low effort and low
travel. It turns out that all 10 Cat skid-steers and all five Multi
Terrain Loaders have pilot-operated controls for drive and loader
functions. And Takeuchi skid-steers have hand pilot controls (joysticks)
for all models of tracked loaders.
Not all manufacturers,
however, think pilot controls are necessary on skid-steer loaders.
"Our control geometry has a very low effort on lever functions,"
says Schaefer. "So there's less value in having pilot controls on
our skid-steers because our mechanical controls have low effort."
Bobcat's skid-steers
don't have pilot controls, but Schulz says the company instead sells
a selectable joystick control option. With that, two joysticks feed
information to a software program, and the software tells the hydraulic
pumps what to do. With the flip of a switch, Bobcat users can change
the controls from the International Organization for Standardization
pattern (left joystick drives; right joystick is work group) to
an H-pattern, with which two joysticks work drive and functions
in combination.
At John Deere, Foster
says all models come standard with foot controls (Bobcat's standard),
and Deere offers hand controls as a factory-installed option on
all models. The company's models 240 through 270 have manual controls,
and the Model 280 uses servo controls.
Following are some recent
product introductions and features from selected skid-steer loader
manufacturers:
Bobcat
In September 2003, Bobcat
introduced the T250 compact tracked loader, which has a rated operating
capacity of 2,500 lb. To comply with new lean manufacturing initiatives,
the company is using the mainframe design of the S220 skid-steer,
which has a radius path lift arm configuration. The T250 offers
11% more power, with 81 hp, than the T200 does.
Bobcat also offers an
all-wheel steer loader, the A300. Especially when used on pavements,
the loader saves on tire wear when compared to a skid-steer loader.
An example comes from Henry Evans, a construction site cleanup contractor
based in Little River, SC. Evans estimates that he gets four to
five times more life from the tires on his A300 than from a skid-steer
loader's tires. Along with partner Robert Hughes, Evans owns E&H
Site Management Inc. Using the A300, the company loads debris from
construction sites into trucks that park on subdivision pavements.
Case Construction
Equipment
Along with Bobcat and
New Holland, Case is a market share leader in the North American
skid-steer loader business. Case recently introduced three new skid-steers:
the 40XT, the 60XT, and the 70XT. Those three replaced models 1840
and 1845, says Schaefer. The three new models range in power from
56 net hp to 79 net hp. With these new models, Case boosted the
power and lifting capacity of the lower end of the skid-steer line.
The upper end of the range encompasses the 75XT, the 85XT, the 90XT,
and the 95XT. At the upper end, the 95XT has 85 hp and 3,650 lb.
of lifting capacity with counterweight.
Because the three smaller
machines have radial path lift arms, Case puts hydraulic self-leveling
on the buckets to prevent spillage of material. Of the larger models,
the 75XT, the 85XT, and the 95XT all have vertical-lift arm linkages
so the arms extend outward at the top of the lift. "That's more
important on larger models," says Schaefer.
What's more, Case offers
ride control for skid-steers. Ride control consists of a hydraulic
accumulator that cushions the lift cylinders and retains material
in the bucket when the machine is traveling over rough terrain.
Caterpillar
Within the last year,
Caterpillar introduced its 287 Multi Terrain Loader, a tracked machine
with vertical-lift arms and a lifting capacity of 3,500 lb., says
Chris J. Key of the company's Sanford, NC, office. The company also
has introduced air conditioning as a factory option or as a dealer-installed
kit on six models of skid-steers. On four models, rear auxiliary
hydraulics have been introduced as a dealer-installed kit, and dedicated
dual-directional controls have been introduced on the 236, 246,
252, and 262 models.
John Deere
The company's new Series
II skid-steer loaders feature more than 100 improvements when compared
to the 1999ñ2001 model 200 Series. Such improvements include the
following:
- Increased operator
comfort with factory-installed air conditioning and quick-tach
for attachments
- Increased reliability
through wet disk brakes, new steering linkage design, new instrumentation,
and new hydraulic control-valve design
- Cushioned boom cylinders
on models 260, 270, and 280
- New, enhanced boom
design for superior visibility
- New standard and optional
suspension seats
- Greater bucket breakout
forces on models 270 and 280
New Holland Construction
The company's LS Series
includes eight models ranging up to 83 gross hp and a 2,800-lb.
lift capacity. New Holland was one of the first manufacturers to
offer a vertical-lift configuration. "Because of the vertical-lift
design, the operator has excellent visibility to both the front
and rear of the machine," says Eric Kohout of New Holland. "The
engine hood is low, and there are no towers to block an operator's
view to the rear."
Adds the company's Jeff
Clifford, "The super boom system moves in a vertical path until
you get just above the operator's platform, and then the load moves
away from the operator. This gives you excellent forward reach and
allows you to dump in the center of a truck more efficiently. Many
competitors do not have maximum forward reach until the end of the
lift cycle. With our machines, you can load high-side 10-wheelers
and low-side super-duty trucks.
So will rubber-track
loaders eventually replace skid steers? "Not necessarily," says
Moore. "They work along with the skid loaders. They're a supplement
to skid loaders."
Author Daniel C. Brown
is the owner of TechniComm, a communications business based in Des
Plaines, IL.
GEC
- March/April 2004
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