Equipment Type

Computers Deliver Just the Blade You Need

Controllers adjust traction to fit the action. Satellites put the blade on grade. Motor graders work smarter, not harder

August 01, 2004

 

Case
Case and New Holland are the most recent big earthmover names to enter the grader market. Case markets three rear wheel drive machines, one with a variable-horsepower option; and New Holland offers a very similar line that adds an all-wheel-drive option on the two largest units.
Caterpillar
Cat's alliance with Trimble makes satellite control of blade position a dealer installed option. The global positioning system can fix the blade's latitude, longitude and elevation and the grade-control computer automatically adjusts blade position until it matches a digital map of the desired grades. Komatsu recently forged an alliance with Topcon to offer similar technology.

Universal Upgrades

 

Some important feature improvements are becoming so common that they don't distinguish one manufacturer's new graders from another.

Emissions-compliant engines — With electronic fuel-injection controls, turbochargers and after-coolers

Electronic transmission — Computer-controlled clutches shift smoothly, and the bump-shift feature changes gears easily

Blade flexibility — Bank cuts up to 90 degrees, and blade reach beyond the tires

Improved cabs — More glass for clear sight lines to the moldboard and tires, and better heating and air conditioning

Easier maintenance — Service intervals are extended, and grease fittings, fluid drains, and filters are grouped and can be serviced from ground level



Motor graders may be the sports car of the earthmoving world. If there's a technology that can improve their performance, there are plenty of buyers who will pay for it. Better final grades translate directly into lower materials costs on projects. So high-tech gadgetry like variable horsepower, hydrostatic front-wheel drive, and automatic grade control are common, if not always standard features on today's motor graders.

 

 

The number of manufacturers building graders hasn't changed much, but the competition at this vanguard of earthmover refinement has nonetheless intensified. Several pillars of equipment manufacturing recently asserted their expertise with motor graders—like when Dodge introduced the Viper and Ford resurrected the Cobra. Komatsu finally replaced the Galion brand with its own name, and CNH launched graders for its Case and New Holland brands. Volvo bought Champion in 1997 to add graders to the industry's newest full line of earthmovers.

Movement by the big nameplates into motor-grader manufacturing is keeping grader technology advancing briskly. An early example of this technology race is variable horsepower. Electronic fuel injection became necessary to satisfy the exhaust-emissions limits for off-road diesels, and variable horsepower (VHP) takes advantage of the computer that controls fuel injection. This electronic brain can be programmed to produce lower horsepower with a unique torque curve to control wheel slip at lower speeds. Performance parameters change in the higher gear ranges, and the engine generates greater maximum horsepower with a different torque curve for better efficiency and hill-climbing power.

A machine with VHP can deliver lots of controlled power when using the inching pedal to finish fine grades, and it can also push a huge head of snow down the road with a V plow and wing plow. This selective power generation is a standard feature on machines in Volvo's B Series and Komatsu Laterra graders. And while VHP is an option on competitive Caterpillar, John Deere, Case and New Holland models, it's typically priced to be easily accessible—about $2,200, for example on a machine with a manufacturer's suggested retail price of more than $230,000.

On-board computers are managing six-wheel power, too. Variable-horsepower machines are often programmed to increase engine power when front-wheel drive is switched on so there's no reduction in torque. Deere and Cat's systems coordinate front-wheel power with the tandems when inching. Volvo automatically disconnects power to the rear wheels when the operator is using the inching pedal, so the tandems freewheel over the finished grade.

Front-wheel drive is hydrostatic, and some systems are designed with dual circuits. The right front and left front wheels are powered and controlled independently, each by its own pump and motor, and each monitored by a speed sensor. They don't rob power from one another, and the computer can synchronize their output with the rear tandems. Cat, Deere and Volvo include switches in the cab of six-wheel-drive graders that allow an operator to dial in the aggressiveness of front-wheel drive to match the job conditions.

Deere reports that its 672CH II with standard six-wheel drive generates more than 39,000 pounds of blade pull—nearly 15,000 pounds more than the 670CH II with the same VHP engine. The all-wheel-drive model weighs 1,600 pounds more and the 60 percent increase in pull comes at a $33,000 price premium (about 17 percent).

The way a grader delivers rim pull is important, but the machine's greatest value remains in its ability to deliver accurate finished grades. High-tech grade systems have assumed significance that rivals power-train advances. Komatsu America formed an alliance with Topcon to outfit equipment with grading systems utilizing the global positioning system (GPS).

Caterpillar forged the first of such agreements with Trimble. Of course, grading technologies by Trimble, Topcon, Leica and any others can be retrofit to most machines. But Cat introduced the industry to grade controls integrated by the manufacturer, and Komatsu's subsequent move suggests that many buyers want the technology to be installed and supported by the OEM and its dealers. As a purchase option, the systems can be financed easily as part of the grader.

A number of grade-control options can be applied to motor graders, or the blade on virtually any other machine. The highest of tech starts with a digital map, or model, of the finished grades designed for a project. This immense database of the specific elevation for every point of latitude and longitude on a site is programmed into the grade-control computer. An antenna is mounted on each end of the machine's blade. A transmitter in the grader communicates through these antennae with satellites orbiting the Earth. The satellites' primary function is to fix the exact latitude, longitude, and elevation of the antennae. This global positioning system helps determine the cutting edge's current elevation and angle, and the grade-control computer compares that to the desired elevations on the digital project map.

Grade-control systems can act as an indicator—providing information the operator uses to decide if he should cut or fill. Or the grade-control computer can be networked to the hydraulic-system computer to automatically adjust the blade position as the grader moves over the site. It can bring the cutting edge to within one-tenth of a foot (20 to 30 millimeters) of the finished grade.

The systems nearly eliminate the need for conventional grade stakes and reduce the need to rework grades to meet specifications. Komatsu claims the Topcon system can cut grading time by as much as 60 percent.

Georgia-based grading contractor, Graham BROS, has been using Trimble's SiteVision GPS grade-control system for 2 years and has SiteVision installed on 29 pieces of heavy equipment, including graders, dozers, scrapers, excavators and soil compactors. The company has graded about 8,000 acres over the past 2½ years for what is expected to be the largest golf community in the United States. They will grade about 24,000 acres by the time the project is completed in 2007, setting the stage for 216 golf holes and associated development.

"Without the Trimble GPS system, we would lose 40 percent of our production," says Tommy Graham, chief surveyor and GPS coordinator for Graham BROS. "We need every advantage available to us."

At this end of the motor-grader market—where contractors need refined earthmoving power to quickly produce precise grades—motor-grader sales present dealers and manufacturers with attractive profit potential. Time will tell if the opportunity is great enough to justify three major manufacturers' (Komatsu, Volvo and CNH) investments in developing grader lines.

Perhaps equipment manufacturers see graders like sports cars, too. Just as the beauty and speed of a Corvette is expected to improve the perception of quality for all Chevrolets, so the performance and sophistication of a grader might raise customer expectations of other earthmovers carrying the same brand. Whatever the reason, it's good to see graders are on the cutting edge of earthmoving technology.

Average Motor Grader Costs
Horsepower List price Hourly cost*
* Monthly ownership cost (based on list price) plus operating expenses, divided by 176 hours
Source: EquipmentWatch.com, phone: 800/669-3282
Most grader models fit between 115 and 199 horsepower. Hourly ownership and operating cost within that broad range only varies from $38 to $46 per hour. Very few models are over 250 horsepower, and that category's average costs are distorted by the 500-hp Cat 24H.
Less than 115 hp $ 61,088 $ 36
115 to 199 hp $216,636 $ 41
200 to 249 hp $253,592 $ 61
250 hp and larger $465,178 $101

Mainline Grader Specifications (by weight)
Company/Model Operating Weight (lb.) Mold-board (ft.) Net Power, 1st Gear Variable Power, (net) Maximum Drive Maximum Blade Pull (lb.)*
* Maximum blade pull is typically calculated at nearly ideal, no-slip conditions, and gross vehicle weight.
Base blade-pull numbers for New Holland and Case graders are identical, but Case only reports base blade pull. Other manufacturers list maximum blade pull, probably calculated using higher gross vehicle weights and maximum horsepower. This table does not include models lighter than 20,000 pounds or the Cat 24H at more than 135,000 pounds.
PSI MG622 22,840 12′ 133 hp 6 × 4 std. n/a
LeeBoy 785 25,300 12′ 130 hp 6 × 4 std. n/a
Caterpillar 120H 27,880 12′ 125 hp 140 hp 6 × 4 std. 17,816
Caterpillar 135H 28,840 12′ 135 hp 155 hp 6 × 4 std. 18,429
Case 845 29,777 12′ 140 hp 6 × 4 std. 14,597
New Holland RG140.B 29,777 12′ 140 hp 6 × 4 std. 18,999
John Deere 670C-II 30,000 12′ 140 hp 6 × 4 std. 24,248
John Deere 670CH-II 30,200 12′ 145 hp 185 hp 6 × 4 std. 24,428
Komatsu GD555-3 30,950 12′ 140 hp 160 hp 6 × 4 std. n/a
John Deere 770C-II 31,000 12′ 155 hp 6 × 4 std. 27,810
John Deere 770CH-II 31,200 12′ 165 hp 205 hp 6 × 4 std. 27,990
Caterpillar 12H 31,320 12′ 145 hp 185 hp 6 × 4 std. 20,677
John Deere 672CH-II 31,820 12′ 145 hp 185 hp 6 × 6 std. 39,310
Case 865 32,077 13′ 169 hp 6 × 4 std. 16,768
Case 865DHP 32,077 13′ 168 hp 190 hp 6 × 4 std. n/a
New Holland RG170.B 32,077 14′ 170 hp 190 hp 6 × 6 opt. 20,626
Caterpillar 140H 32,357 12′ 165 hp 205 hp 6 × 4 std. 29,121
John Deere 772CH-II 32,820 12′ 180 hp 210 hp 6 × 6 std. 43,860
Komatsu GD655-3 33,069 12′ 165 hp 190 hp 6 × 4 std. n/a
Volvo G710B 33,400 12′ 141 hp 166 hp 6 × 4 std. 21,343
Caterpillar 143H 33,670 12′ 165 hp 205 hp 6 × 6 std. 30,303
Volvo G720B 34,000 12′ 164 hp 210 hp 6 × 4 std. 21,726
Caterpillar 160H 34,560 14′ 180 hp 220 hp 6 × 4 std. 31,104
Komatsu GD675-3 34,854 12′ 180 hp 200 hp 6 × 4 std. n/a
Volvo G726B 35,400 12′ 198 hp 235 hp 6 × 6 std. 31,121
Volvo G730B 35,500 12′ 198 hp 221 hp 6 × 4 std. 22,685
Caterpillar 163H 35,890 14′ 180 hp 220 hp 6 × 6 std. 32,229
Volvo G740B 37,126 12′ 219 hp 243 hp 6 × 4 std. 23,389
Case 885 37,950 14′ 200 hp 6 × 4 std. 20,095
New Holland RG200.B 37,950 14′ 200 hp 6 × 6 opt. 23,955
Volvo G746B 38,250 12′ 219 hp 243 hp 6 × 6 std. 32,589
Caterpillar 14H 41,465 14′ 220 hp 240 hp 6 × 4 std. 37,319
Komatsu GD750A-1 42,000 14′ 225 hp 6 × 4 std. n/a
Volvo G780B 43,250 14′ 219 hp 243 hp 6 × 4 std. 27,248
Caterpillar 16H 54,550 16′ 265 hp 285 hp 6 × 4 std. 38,857
Komatsu GD825A-2E 58,250 16′ 2″ 280 hp 6 × 4 std. n/a


Web Resources
Case
www.casece.com
Caterpillar
www.cat.com
John Deere
www.deere.com
Komatsu
www.komatsuamerica.com
LeeBoy
www.leeboy.com
New Holland
www.newhollandconstruction.com
Volvo
www.volvoce.com
PSI
www.askpsi.com
   

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