Controls, engines, and transmissions make strides forward.
If you’re
looking to compare the latest motor graders among the various manufacturers, we
don’t know of a better place than CONEXPO-CON/AGG 2008. So last March we
attended the big show in Las Vegas and made the rounds among several grader
manufacturers, who greeted us with a cornucopia of new machines and
features.
Caterpillar
says its new M-Series takes a “revolutionary approach” with its pair of
joysticks that replace an eight-lever control system and a steering wheel. And
indeed, the joysticks have generated a great deal of buzz in the industry. The M
models have been in the field since early 2007, and we were curious about how
customers are receiving the new machine. The answer: “Customer acceptance has
been fantastic,” says Patrick Kearns of Cat’s North American Commercial
Division.
With the two
joysticks, one for each hand, Cat says it has greatly reduced the hand and body
movement required to control the grader. “The controls are intuitive,” says
Kearns. “To turn the circle you twist your right hand. To steer the grader to
the left, you move the joystick left, and to steer to the right, move it
right.”
Kearns says the
two electro-hydraulic joysticks control the basic eight functions of the grader
and an articulation return-to-center button. Logical grouping of hydraulic
functions in the joystick allows for maximum operator efficiency and comfort.
The result is more productivity for the customer and more comfort for the
operator by reducing hand and arm movement significantly when compared to
conventional controls.
With the M
Series, Caterpillar solved a problem, expressed by some customers, with
servicing the drawbar-circle-moldboard assembly on previous models. “We were
able to greatly reduce the service time considerably over the H Series by going
to a top-adjust system,” says Kearns. By removing the access plates located on
the top of the drawbar, a mechanic can add shims for wear-strip adjustment or
replace the wear strips at the end of useful life. Changes to the moldboard
retention system and the slide-rail wear inserts make the moldboard much easier
to service. The new bidirectional slide-rail shoes allow adjustment up and down
as well as fore and aft.
 |
| Photo: Case |
| The engines on the 800 Series from Case are electronically
controlled and fuelled through high-pressure, common-rail, fuel-injection systems providing responsive control
and fuel efficiency. |
Caterpillar
says the M Series all-wheel-drive option delivers 42% more torque than the H
Series system. The M Series uses dedicated left and right pumps, which allow
independent control of hydraulic flow to each front-wheel hydrostatic motor. To
compensate for hydraulic power demand, the engine automatically delivers
additional horsepower to provide constant net power to the ground. The new
all-wheel-drive system also offers a front-wheel-only hydrostatic mode and
exclusive steering compensation. Caterpillar offers the all-wheel drive with the
120M AWD, 140M AWD, and 160M AWD motor graders.
All-Wheel Drive
Over at Volvo
Construction Equipment’s stand at CONEXPO, we caught up with Gary Atkinson,
regional product manager with Volvo Road Machinery. He explained that the
company’s G900 family of graders is a “clean-sheet-design,” resulting from a
special program of customer input. Previous Volvo models had Champion grader
heritage.
The G-900
family consists of seven models—two all-wheel-drive units and five tandem-drive
machines. Engines range from 155 to 265 horsepower.
Notable
features on the G900 family include:
- A new front axle with tighter turning radius and reduced maintenance;
- A stiffer, stronger frame;
- A new cab with a high-output air-conditioning and heating system; and
- A Tier 3–certified engine and redesigned cooling system.
“We moved to a
much more technically advanced transmission,” says Atkinson. “Now we have two
transmissions, the HTE 840, with eight forward and four reverse gears; and the
HTE 1160, with 11 forward and six reverse gears.” Those transmissions use
pulse-width modulation. “The goal is to provide smooth shifting from one gear to
the other and better control over the shift points.”
 |
| Photo: Volvo |
| Volvo’s new 900 family consists of seven models with engines
ranging from 155 to 265 horsepower. |
Clutch packs
typically use disks that lock up with hydraulic pressure, says Atkinson. But
with modulation, the clutch packs engage gradually, so that you get a smoother
shift. Shifting is electronically controlled. A vehicle electronic control unit
(ECU) communicates with the engine ECU to provide control over throttle
functions and transmission-related functions. There is also a third computer, an
instrument ECU. The combination of those three ECUs enables the operator to
control grader functions and to provide for electronic diagnostics.
The three ECUs
are tied into a system called Care Track. It’s a telematics system that
interfaces with the Internet through GPS satellites and provides access to a
wide variety of information, such as machine hours, transmission usage in each
gear, time spent in different rpm ranges, and more. The system can flag improper
clutch usage, express fuel consumption, flag low engine oil pressures, and
diagnose a wide variety of problems.
“This is an
exceptional tool that allows for trouble-shooting of machine or operator
problems from a remote location,” says Atkinson. “In many cases, mechanics can
pinpoint the problem and have the required tools and replacement parts with them
thus reducing the need for multiple trips to repair a failure.
“The objective
is to help the equipment manager to coach his operators,” says Atkinson. “For
example, if an operator can run in a higher gear at lower engine speed, we can
improve fuel efficiency. Volvo’s HTE1160 transmission allows for precise control
of engine rpm’s at the operator’s desired ground speed to exactly match the
application at hand.”
Deere’s G-Series
John Deere
introduced its new G-Series of six motor graders at CONEXPO. The
Tier-3-compliant G models, which replace the D-Series, will be available in the
early to mid-2009, says Jeff Rowan, product-marketing manager for motor
graders.
 |
| Photo: Caterpillar |
| Caterpillar’s new M Series of graders features a pair of joysticks
in the place of the eight-lever control systems found on its older
models. |
With the new
G-Series, Deere offers electric controls on the seat to replace the old
mechanical controls that required hydraulic valves on each side at the floor
level in front of the cab. The absence of those valves improves visibility to
the ground, Rowan says. Deere will, however, continue to offer mechanical
controls to those who want them—especially governmental customers.
Deere kept the
steering wheel on the G-Series—or you can steer with a left-hand joystick. The
joystick controls the side shift of the blade and can control steering, too.
“Customers told
us they don’t want more functions on the joystick,” says Rowan. “They told us if
you try to do too many things with your hand, you’ll get cross-talk of the
functions.
The new
electric controls allow Deere to integrate aftermarket GPSs from either Topcon
or Trimble, Rowan says. “This eliminates the need to put a Deere valve on, then
a Topcon valve or a Trimble valve,” says Rowan. “Our system allows you to work
with Trimble or Topcon equally well.”
And now Deere
has begun to offer a mid-mount scarifier. “Our old frame sloped down in front
and didn’t allow us space for the mid-mount scarifier,” says Rowan. “The new
frame rises higher toward the front.”
With the
G-Series, Deere is using event-based shifting (EBS), not time-based shifting.
Event-based shifting controls the shift based on the load being carried by the
blade, not on the time it takes to fill the clutch packs. If you’re carrying a
heavy load, you want a fast downshift—but you want a slower shift with a light
load, which EBS gives you. “The operator doesn’t have to step on the clutch,”
says Rowan. “They can shift the transmission ahead of time, and the operator
can’t even tell when the machine shifts, it’s that smooth.”
New
From Case
In January
2007, Case Construction Equipment announced a Tier 3 upgrade to its 800 Series
motor grader line. The new engines on the 800 Series are electronically
controlled and fueled through a high-pressure, common-rail, fuel-injection
system. That provides responsive engine control, greater fuel efficiency, and a
cleaner burn.
Increased
horsepower across the entire Case motor grader line supplies additional power.
The 845 DHP (dual horsepower) model maintains the horsepower range required to
meet the demands of fine-grading applications, while also providing an increase
of 14% for tough conditions.
The 865 VHP
(variable horsepower), the most popular machine in the Case motor grader lineup,
still incorporates all of the most recent enhancements to productivity while
delivering an increased 205 net horsepower. Variable horsepower allows a range
in power to match the needs of the application at hand by delivering better
traction control and maximizing fuel economy.
“Plug
and Play”
Komatsu has
announced plans to introduce “Plug and Play” capability for Global Positioning
Systems in the latter half of 2008. The company says either Topcon or Trimble
systems will be compatible with Komatsu motor graders.
Komatsu’s
Construction Equipment Division motor grader line consists of three variable
horsepower models, the GD555-3 (140 net horsepower to 160 horsepower); the
GD655-3 (180 horsepower to 200 horsepower); and the GD675-3 (180 net
horsepower–200 horsepower). All three models are powered by Komatsu-branded
engines, and all three are tandem drive. Komatsu does not currently offer
all-wheel drive models.
Key features
and benefits include the following:
Dual mode transmission—either direct or torque
converter drive. The operator can select either mode with the flip of a switch.
Torque converter drive allows the operator total control in fine grading
operations.
- Excellent operator visibility to the blade—you
can see the heel and toe of the blade.
- Quick response—Komatsu-designed hydraulics
result in low effort and quick response to operator inputs.
- Excellent turning radius—The machine can
operate in tight-radius cul-de-sacs and requires less room to maneuver, the
company says.