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If a grader were a person,
he might be called ungainly, awkward, or even a klutz. Cynics might
say it was only a blade used to push gravel, sand, and snow to the
side. "Cumbersome" is what my neighbor named the old grader that
turned the gravelly alley behind his house into a smooth thoroughfare
again. His mistake was that he watched the machine and not the job
it performed. Motor graders are, in fact, some of the most accurate
machines in construction. A good number of those yellow, spidery
machines have been working efficiently for 20 or 30 years now; you
would find it difficult to name a piece of construction equipment
that has done better service or offered such longevity.
As with all machines whose precise performance sometimes
defies the public imagination, the operator has something to do
with that success. Many contractors say they try to keep good grader
operators when they find them, primarily because getting it right
the first time is one of the guaranteed methods of making a job
profitable. "The last guy on the job is the grader operator,"
says Mitch Stoltenberg at M&S Grading Inc. in Omaha, NE. The
company has performed many subdivision projects where the graders
do the finish work but also keep the haul roads for scrapers and
trucks in good condition. "The grader does the finish work,
the last segment of preparation. That is what our customers see.
It is the finish accuracy that the customers appreciate, so our
grader operators are the most important people for the image and
reputation of our company."
Nor do manufacturers belittle the role of the operator.
"Technology has come a long way in guiding motor graders,"
asserts Bob Post, grader product manager for Komatsu. "There
is still a need - and I believe the need will continue for a
very long time - for skilled grader operators. There will always
be times when the laser or GPS [global positioning system] technology
cannot or does not work and an operator will have to do the precise
work. Training future grader operators to develop their own skills
rather than simply depending on technology should be a prime concern
for all dirtmoving contractors." Volvo Construction Equipment
agrees that the importance of the operator cannot be underestimated.
"Paying attention to an operator's needs is vitally
important and is the main driver behind our Voice of the Customer
development process," comments Brian Lowe, product and communications
manager for Volvo.
Homework to Do
That range of sizes mentioned above varies from manufacturer
to manufacturer, with all of the specification information you require
readily available at the dealership or on the Internet. Many contractors
note that the size of the moldboard is as good a place as any to
start sizing the machine that would be best for normal work. "If
14 feet is going to be too large for many of your jobs, get a smaller
one," comment several. "If all of your work is in highway-type,
wide spaces, get the machine with the most power, best weight, and
biggest moldboard," confirm others. A 12-ft. blade seems especially
popular because it can manage a generous 10-ft. pass, but you still
can adjust the angle so it is readily transported on an 8-ft. lowboy
trailer. One of the points made by New Holland Construction about
its graders is that the moldboard is a rollaway design; it can roll
the material down the moldboard and not simply doze it.
In Case's 800 Series motor graders, net horsepower
ranges from 140 to 205, and operating weights go from almost 30,000
to just less than 38,000 lb. The standard blades vary from 12 ft.
on the 845 to 13 ft. on the 865 and 14 ft. on the 885. "We
offer the best in serviceability and maintainability," says
David Wolf, marketing manager for Case motor graders. "We
have the flip-up rear hood for quick access to the engine, filters,
and daily service points. Combine these with drop-down side panels
along the bottom of the hood for additional access. The circle has
a 360° rotation and externally mounted teeth for easy cleaning,
along with additional surface area for reduced wear." Case
joins other manufacturers in its consideration of the operator.
"There is a front articulation point so the operator always
knows the relationship between the back half of the machine and
the front," adds Wolf. "The ergonomically designed cab
offers operator comfort and increased productivity." On Case
graders, the moldboard has "an involuted curved design to
boil material in front of the blade with less power and reduced
fuel consumption." New Holland's graders offer weights
from 15,000 lb. (on the RG80) to 35,452 lb. (on the RG200). In the
seven models, the horsepower goes from 76 to 205. The biggest model
(the RG200) has a top-speed forward of 26.8 mph. Standard moldboard
for this model is 14 ft. Its length is 337 in. At the other end
of the New Holland range, the RG80 (76 hp) has a top-speed forward
of 25.1 mph and a length of 260.6 in., and its standard moldboard
is 10 ft.
Blade, Weight, and Power
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| This
Roadrunner attachment goes on the back of a tractor for grading
smaller widths. |
Komatsu America International
Company's Laterra motor graders have what the manufacturer terms
a "circular geometry blade." This feature permits a 90° bank
slope position (a "true 90°," says Komatsu). That promotes easy
blade maneuvering while still offering good ground clearance and
reach. The design also has two pinions on top of the grader's saddle
for superior support. Komatsu's GD555-3 Laterra uses a Komatsu SA6D102E
turbocharged and aftercooled diesel engine to give 140 hp (160 hp
of the GD555 variable horsepower, or VHP, version). The GD655-3
Laterra provides 165 hp (190 hp on the VHP version), and the GD675-3
gives 180 hp (200 hp on the VHP version). The operating weights
for these three models go from 30,525 to 34,390 lb. "Small graders
are great for tight quarters or if a 12-foot moldboard is all the
contractor needs," says Post. "For heavier-duty jobs, such as spreading
stone, a contractor will want more horsepower and weight and probably
a bigger moldboard. Weight will also be an advantage if the material
to be graded is difficult to penetrate."
"If
your application or work site has constantly poor traction conditions,
you should consider an all-wheel-drive grader; it can be the solution
for increased productivity and, more importantly, getting the job
done on time," says Lowe. "The Volvo G746B All Wheel
Drive Grader is the most powerful in the industry. It develops 32,598
pounds of blade pull and is ideal for road construction, road maintenance,
ditch cutting, ditch cleaning, snow clearing, and all heavy-duty
operations." The drive system of Volvo All Wheel Drive Models
is like having three different drive systems in one grader. In six-wheel
drive, all six wheels are powered to grip the ground in poor footing
and add an extra 8,500 lb. of pull in front of the moldboard, a
practical function for clearing wet ditches and working on bank
slopes. With the front drive disengaged, the operator has an efficient
tandem-drive grader ready for such operations as top-of-road work
or roading. The change from six-wheel drive to tandem drive can
be made with the simple flick of a switch. A unique feature of Volvo
B Series All Wheel Drive Graders is Creep Mode. The grader also
can be operated using the front wheels only, offering infinitely
variable ground speed from 0 to 2 mph. Creep Mode allows the moldboard
to be pulled, not pushed. "This" the operator the unique capability
to perform fine grading without scuffing the work behind the moldboard,
even around the tightest radius," explains Lowe.
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| John
Deere graders have a history of successful highway work, on
the pavement or the shoulders. |
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Improvements
to Caterpillar's 120H, 135H, and 12H graders were designed to achieve
higher productivity and lower operating cost. VHP (variable horsepower)
and VHP Plus give the user a more precise delivery of power because
the system adjusts according to gear selection. Models 120H and
135H can have VHP to give additional power in fourth through eighth
gears. The 12H can be supplied with VHP or with VHP Plus (which
gives an additional 11% power when contrasted with the VHP). The
120H has a 125- to 140-hp power range, and the range of the 135H
is 135-155 hp. The 12H goes from 145 to 185 hp. The standard blade
for all three improved models is 12 ft., and the height of the moldboard
is 24 in. Officials at Caterpillar stress the importance of torque
in running a grader efficiently. The increased lugging capability
on the three models mentioned means that the operator can expect
consistent grading speeds without needing to downshift. The maximum
rimpull is higher now (11% higher in the 120H and 135H and 14% higher
in the 12H). Weights for these three Caterpillar models range from
27,880 to 31,320 lb., and the circle diameter for all three is 60.2
in.
If you think specifications for motor graders from different
manufacturers are quite similar, that is because they address known,
similar problems. Horsepower and weight are comparable and moldboard
choices are based on identical job demands. John Deere graders range
in horsepower from 140 to 205 and have basic operating weights in
the 30,000- to 33,000-lb. range. The minimum turning radius of the
670C-II is 22 ft. Its typically equipped operating weight is 35,990
lb. with power coming from a 151-hp John Deere PowerTech engine.
The 770C-II brings advanced Hydrostatic Front Wheel Drive to deliver
more power to the ground. The system has a speed-sensing control
that sends power to each wheel as it is needed. A 6081H John Deere
engine delivers up to 205 hp (as well as a 53% torque rise in the
high gears). Its typically equipped operating weight is 40,835 lb.,
and its turning radius is still only 22.5 ft. On these John Deere
graders, there are lube-for-life driveshafts for longer service
intervals and bronze wear inserts for the blade circle to reduce
maintenance costs.
Attachments
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| A volvo
grader with all-wheel drive |
There are attachments
for graders too. Defying the criticism that they are merely self-propelled
moldboards that push sand and gravel to the side, graders can have
scarifiers and rippers that enable them to deal with that extra-hard
ground, rip up old highways and streets, and even act like dozers
for pushing construction debris. One of the most frequently mentioned
jobs for graders in the public sector is making and maintaining
ditches. You will see graders keeping our rural roads in shape.
There are more than 1.5 million mi. of gravel roads in the United
States. Will they ever be paved or oiled? In growing communities,
the roads will be paved. In most of the counties involved, there
is no population growth and little likelihood of better roads. It's
on those rural roads that the public seems to notice graders - there
and when they clear the interstates and highways of that cold, white
stuff that impedes travel in the more northerly states for several
months of the year. The tasks of the gravel-road grader are to maintain
the specified crown and to avoid high shoulders or unwanted ditches
at the edges.
Interestingly, more and more of that roadwork seems to
be going to contractors rather than public works departments. Could
it be that the contractors have the most skilled operators? "We
do driveways, ditches, and shoulders with our graders, but contractors
tend to do the highways," notes Mike Hartwig of the Kansas
Department of Transportation (DOT). "Our graders do our dirt
roads and ditches," confirms Hari Karikaran, senior engineer
at Charleston County Public Works in South Carolina. The Alabama
DOT has three interstates and half a dozen national highways in
its territory. "The state has a motor patrol, and we maintain
shoulders," says Lee Reach at the Alabama DOT. "The
counties use their graders for similar work and ditches."
It seems that the more rural areas of our country are
the breeding grounds for ways to improve the basic performance of
any agricultural or construction machine. People make jokes about
farm boys fixing tractors with baling wire, but their history of
practical attachments is much more impressive and technical than
that. In Pennington County, SD, there are some 500 mi. of gravel
road to be maintained. It used to take two workers, one with the
grader and another with a roller. The county then saved money, manpower,
and time by attaching a specially designed roller to the graders.
When such jobs as spot graveling are needed, the motor grader is
also a roller. Volvo motor graders are designed with a full rear
perimeter frame, excellent for mounting attachments, as any shock
load from the attachment is directed to the frame and not to power-train
components as with other designs.
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| Graders
can do more than maintain rural roads and ditches. |
The Roadrunner grader
from Roadrunner Construction Equipment is the grading equivalent
of a tow-along scraper. It attaches to a 30- to 125-hp three-point-hitch
tractor and offers grading widths from 6 to 10 ft. Put it
behind a skid-steer loader and it will handle grading widths of
6-7 ft. The Roadrunner, too, has an optional roller attachment.
The manufacturer says its dual-blade configuration eliminates potholes,
ruts, and washboarding without leaving windrows or pushing aggregate
out of the roadway. This pull-along grader has been successful for
embankments, slopes, leveling, earth dams, and golf courses; it
spreads and levels all types of roadway construction.
Along with attachments, grade control systems should
be mentioned. There are (sometimes confusing) options with these
helpful systems. They can be LPS (local positioning system) or GPS.
The suppliers will toss such phrases as "plug-and-play"
and "sensor independence" in your direction. Will your
application be better with a sonic tracer or a rotating laser? Don't
be put off by the jargon of the technologies. The systems can improve
productivity and save money with actions that are quite simple and
easy to learn. Manufacturers Trimble, Apache, GeoLogic, Leica Geosystems,
Laser Leveling, and Topcon have shown good customer education and
support.
Compact, Medium, or Large?
LeeBoy
manufactures compact graders. There's nothing inferior about
the 635. Its Lombardini engine gives 47 hp, its cab is fully enclosed,
its scarifier is center-mounted, and it offers two-speed hydrostatic
drive and tandem drive. The compact LeeBoy 635 motor grader weighs
6,750 lb. Its length is 17 ft., 8 in.; its width is 6 ft.; and its
height is 7.5 ft. You can understand why contractors use graders
like this for smaller jobs or where maneuverability is critical.
The sliding moldboard is 8 ft. wide and 14 in. high, and it has
a sideshift of 24 in. and a tilt of 30°. The lift above ground
is 9.5 in., the penetration is 6.5 in., and the rotation is 85°.
Other features that LeeBoy emphasizes are the articulated design
(with 18° in either direction) and the enclosed turntable (to
prevent wear from dirt or moisture). This manufacturer also offers
the 685 model. Many design features are the same, but the 685 has
a 110-hp Cummins Turbo Diesel engine, a 10-ft. moldboard, and a
weight of 15,200 lb. Sideshift reach is 36 in.
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Most paving companies
own at least one grader (and it might not be the latest model, so
durable are these machines). Century Construction, headquartered
in Lewistown, MT, and serving several states, owns a fleet of graders
of different sizes. "We have some small graders you could use on
parking lots or projects like the renovation of the forecourt for
a gas station or trail stop along the interstate," observes Chad
Sciuchetti, purchasing manager at Century. "Their maneuverability
and accuracy are something to see! Mostly our graders are helping
on bigger highway and street projects, so we use the whole range
from small to large, according to the local conditions."
Contractors whose grading projects are mostly in the
residential market do not all own motor graders and use grading
attachments to compact loaders and the like. "Most of our
work is relatively small, so we do not need a full-size grader very
often," says a representative of Troy Scott Custom Grading
in Lincoln, CA. "If we have a project where a larger grader
is the practical answer, we will rent one."
Volvo (with a history of grader manufacture that goes
back to 1875) has three graders with horsepowers less than 100:
the G60, the G66, and the G80. The G60 and the G66 have a turning
radius of 16.5 ft. They offer single-axle drive or all-wheel drive
and a sliding moldboard of 10 ft. The G60 weighs 12,800 lb., and
the G66 weighs 600 lb. more. Attachments available for these compact
graders include automatic blade control, a rear-mounted ripper,
a front-mounted V scarifier, a side dozer, a rotary broom, a windrow
eliminator, and two front-mounted blade scarifiers (one 7 ft., the
other 8 ft.). At the top end of Volvo's lineup of graders
are the G700B Series. The B Series line of motor graders comprises
five tandem-drive and two all-wheel-drive models, all suited to
public- and private-sector tasks. The tandem-drive machines range
in operating weight from 33,400 to 43,250 lb. and have engine outputs
of 179-243 hp; the all-wheel-drive operating weights range
from 35,400 to 38,250 lb. and run on 221- to 243-hp (175- to 181-kW)
engines. The flat torque curve delivered by Volvo engines reduces
the need for downshifting, which makes the job easier for the operator.
What Really Matters?
"On most grading equipment, power, digging ability,
and tractive effort - however you wish to describe it - are
the most important considerations," proposes Bob Post of Komatsu.
"The operator is also looking for other things. Visibility
is critical on a grader for just about any job it does. Hydraulics
have to be responsive in order for the operator to fine-grade or
for a laser system to work up to its potential. The transmission
must be smooth and easy to operate for the control of round speed
and tractive effort while the operator is concentrating on holding
his grade. And machine balance is important is almost every application."
In response to customer input for improved hydraulic
response and reliability, Volvo introduced a hydraulic system with
the B Series motor graders. The foundation of the new system is
a 0- to 75-gpm axial-piston hydraulic pump offering increased efficiency
and optimum pump life. "Combining the advantages of the high-torque
capability of the Volvo engines with the large variable displacement
hydraulic pump allows an operator to reduce first-gear ground speed
by operating at a lower rpm and retain full hydraulic control. This
permits precise moldboard positioning to match the grade requirement,"
concludes Lowe.
Paul Hull writes on construction and environmental
topics for several international magazines.
GEC
- May/June 2004
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