Grading and Excavation Contractor | Excavators Reach to New Heights

Comment On This

Create A Link
To This Article
On Your Website

Improved hydraulics and operator comfort characterize new models.

By Daniel C. Brown

Somebody should yell “Fire in the hole!” Indeed, the past few years have seen a veritable explosion of new technology in hydraulic excavators. As manufacturers have introduced new engines to meet Tier 3 exhaust emission requirements, these companies have upgraded excavators’ hydraulic systems, added remote communications systems, introduced reduced tail swing models, and improved operator comfort.

Manufacturers are approaching excavator hydraulics with greater sophistication than ever before. John Deere, for example, has moved away from its former swing-and-boom priority work modes, and now offers just one work mode.

“Technology has progressed far enough that we can let the machine do that thinking for the operator,” says Mark Wall, excavator marketing manager at Deere’s Construction and Forestry Division.

The business end of a New Holland E160 swings into action at an excavation project.

“Hydraulic responses are calculated automatically by the machine. If I move the lever slowly, I get a slower response, and if I move it quickly, I get a quick response. We get a very predictable response.”

Caterpillar, for its new D-Series models, has made a heavy lift circuit standard. At the touch of a switch, heavy lift boosts hydraulic pressure for increased lift performance.

What’s more, Caterpillar’s D-Series excavators feature a wide range of factory-installed auxiliary hydraulic systems, including a one-way, high-pressure, high-flow circuit for hammers and vibratory plate compactors. Also, a two-way circuit is available for thumbs and other hydra-mechanical work tools.

An optional Tool Control System for Cat’s D Series allows operators and technicians to set auxiliary hydraulics flows and pressures using the monitor inside the cab instead of using expensive
service tools.

The end-user can pre-set and store up to 10 flow and pressure settings for 10 different hydra-mechanical work tools.

At Komatsu, the new PC160LC-7 model is equipped with four working modes designed to match engine speed, pump speed, and system pressure with the current application. Power Mode provides maximum power and production for applications requiring fast cycle times. Economy mode reduces fuel consumption by 13%, compared to a previous model in Active Mode. Lifting Mode increases hydraulic pressure by 7%, and Breaker Mode provides optimum engine speed and hydraulic flow to match attachment requirements.

That’s not all. Komatsu’s PC400LC-8, with an operating weight of about 100,000 pounds, features two boom mode settings, five working modes, and Power Max control. The modes are designed to match engine speed, pump flow, and system pressure to specific job requirements. The PC400LC-8 is equipped with both a single-action circuit and a double-acting circuit for attachments that require two-way flow. In hard digging applications, a one-touch Power Max Function increases digging force by 7% for eight seconds, creating a noticeable difference in digging performance.

Both New Holland and Kobelco offer a power boost switch that increases hydraulic power by 10% for as long as needed. On New Holland’s E160 and E215 models, the Independent Travel System makes lifting and carrying objects easier by reducing the need to “feather” the controls. A separate pump is exclusively dedicated to the travel system so the excavators maintain speed when raising the load while traveling.

Volvo Construction Equipment says its new Tier 3–compliant machines offer “intelligent hydraulics.” The hydraulic systems feature boom, arm, and swing priority. Volvo says that in-cab selectable hydraulic flow and pressure increases performance, especially when regularly changing attachments. The hydraulically driven fan is operational only when needed, which saves fuel.

Fuel Efficiency
Case Construction Equipment says its CX B line of full-sized excavators delivers a 20% increase in fuel economy over preceding models. “Think about what 20% better fuel efficiency means,” says Dave Wolf, marketing manager, Case Construction Equipment. “That’s huge. During testing, we were seeing almost a gallon an hour difference in fuel use. If you multiply that times 2,000 hours per year, times $2.50 per gallon for diesel fuel, that’s a savings of $5,000 per year that goes straight to the bottom line.”

Case’s new lineup includes the CX160B, the CX210B, the CX240B, and the CX190B, which deliver 120, 157, 177, and 207 net horsepower, respectively.

Wolf also says that at the same time Case excavators deliver increased fuel efficiency and horsepower, they provide a substantial increase in productivity. “In our testing, they easily moved 25% more cubic yards of material per gallon of fuel,” he said.

Case excavators’ increase in productivity is the result of increased hydraulic flow. Hydraulic horsepower has been increased by 4% to 10% across the line. “Our Case CX excavators have always used regenerative hydraulics on the boom and arm,” said Wolf. “Now we’ve added it to the bucket curl, which speeds the time required to get a bucket of dirt.”

Reduced Tail Swing
In recent years, most manufacturers have begun offering reduced tail swing models, or even zero tail swing units, for which the body swings within the tracks.

Now Caterpillar has introduced three new mid-sized excavators, each with a different swing radius for different applications. The 320D L has a standard swing radius; the 320D LRR has a reduced swing radius; and the 321D LCR has a compact radius.

The Cat 320D L, with an operating weight of 47,554 pounds, replaces the 320C L and has a standard tail swing of 9 feet. It is designed for heavy construction and offers the largest digging envelope of the three.

The Caterpillar 320D LRR replaces the 320C LU. The 320D LRR has a reduced tail swing radius of 6 feet, 7 inches. The machine has a full-sized cab, and is well suited for areas with restricted space, such as city alleys and industrial demolition uses.

The third machine in the group, the Cat 321D LCR, replaces the 321C LCR and has a tail swing radius of 5 feet, 6 inches. This excavator is designed to rotate with little to none of the counterweight extending beyond its tracks. The boom is positioned further back in the upper frame as compared to a standard excavator. That design reduces the front swing radius when the boom is pulled up for easier operation in restricted spaces.

Communication Systems
John Deere, Komatsu, and Caterpillar all offer GPSs that allow end users to communicate remotely to their excavators. Typically, the systems use cellular telephone technology. Deere’s system is called JDLink, which Wall says will be an option on some excavator models–and standard in the fall of 2007 on the 450D, 650D, and 850D excavators.

JDLink automatically collects, transmits, and manages information about where and how construction equipment is being used. The system also enables users to monitor critical machine health data.

At least three levels of service are offered with JDLink. The Standard level will provide owners—at a Web site—with machine location status, machine service hours, and location monitoring capabilities.

The Advanced Level will have Standard level information, plus dash indicators, and fuel and equipment utilization information.

The Ultimate level expands on those offerings by adding current and stored monitoring of component pressures and temperatures, fuel consumption, as well as transmission gear selection, and full-featured diagnostic information retrieval.

Komatsu offers a similar system, called Komtrax, as standard on all its excavators. Komtrax sends machine-operating information to a secure Web site using wireless technology. Komatsu says its system increases machine availability, reduces the risk of machine theft, allows for remote diagnosis by the equipment dealer, and “provides a wealth of other information to drive business efficiently and productively.”

Cab Improvements
Most manufacturers have paid a great deal of attention to operator comfort in recent years. Volvo says its new C-Series has better controls, more space, more glass, less noise, and less vibration. Visibility is improved, especially in the upper and lower portions of the cab.

At Komatsu, the new PC160LC-7 model is equipped with four working modes designed to match engine speed, pump speed, and system pressure with the current application.

Multi-adjustable seat, pedals, and joystick offer an optimum-operating position for all operators. The enhanced suspension system surpasses emerging cab vibration requirements, which reduces operator fatigue and whole body vibration. In-cab noise levels are reduced, thanks to the low-revving engine, redesign of the cooling system, and to the pressurized insulated cab itself, which blocks sound. A new color LCD display is easy to read and works well even in bright conditions.

Wheeled Excavators
Earlier last year, Volvo introduced its new C-series of E-wheeled excavators. The EW160C and EW180C have all of the benefits of Volvo’s new C-Series crawler excavators, the company says. The C-Series offers more powerful Tier 3–compliant engines with V-ACT, which stands for Volvo Advanced Combustion Technology. Not only does the engine deliver exemplary fuel efficiency, it produces high torque at low engine speeds. The engine management’s anti-stall system balances maximum available power to hydraulic output, which prevents the engine from becoming overloaded, regardless of engine speed or pump demand.

Liebherr, a German manufacturer, offers a complete line of hydraulic excavators, ranging from the 20,200-pound R904C Litronic model to the R995 and R996, both mining-sized machines. The R996 has a 33 cubic-meter bucket size and a 3,000 horsepower powerplant. The R996 weighs a whopping 659,000 pounds. Mid-sized machines include the R924C Litronic, with 177 horsepower, and the 203-horsepower R934C Litronic.

Terex also offers a full line of 21 crawler and wheeled excavators, with operating weights ranging from 3,638 pounds to 104,900 pounds. The company says advanced hydraulic circuitry separates the oil flow for the travel and boom functions to assure precise operations when handling loads during travel. An anti-rebound swing valve is installed as standard equipment to assure precise and smooth stops during dumping or cradling a bucket of material.

Terex mounts its excavator cabs with a viscous-sealed mounting system coupled with a frame, cabin, and seat designed to absorb major and minor vibrations.

Excellent cabin sealing characteristics reduce noise to a low 74 decibels (A).

By connecting a laptop computer to a Terex excavator’s e-POS controller, data such as pump pressure and engine speed can be displayed graphically. Other machine status readings can be stored in memory and printed out. A pull-out style drawer for electrical controls allow for easy service and maintenance, Terex says.

From the economy models to high-end performance machines, today’s range of excavators offers something for every buyer. Operator comfort has been improved universally, but there are differences in hydraulic systems and power trains. Want to know more? Check out these models at your
local dealership.

Daniel C. Brown is the owner of TechniComm, a communications business with headquarters located in Des Plaines Illinois.

GEC - March/April 2008

Back To Table
Of Contents