Loaders Reach New Heights

Sept. 1, 2010
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Like Thanksgiving apples and oranges spilling from a horn of plenty, new loaders and loader technologies recently have been emerging from their manufacturers.

Here’s a sampling:

  • Caterpillar just introduced the 973D, a new track loader that features load-sensing hydraulics, joystick steering, and 10% more power than its 973C predecessor;
  • John Deere recently introduced its K-Series of wheel loaders, which offer joystick steering as an option on the 544K through the 824K and as standard on the 844K;
  • Volvo Construction Equipment recently brought out its OptiShift technology on the L150F, L180F, and L220F wheel loaders. Volvo OptiShift includes two new features: a new torque converter with lock-up and a free wheel stator, and the patented Reverse by Braking feature. The benefits: improved fuel economy and productivity. More on that follows below.
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Joystick Steering
Most of the major manufacturers offer joystick steering, especially on larger models. That’s because production loading-a repetitive task involving a series of 90-degree turns-is usually the task of large loaders. The operator must dig into the face, back away, turn, line up with the truck, move to the truck and dump, back away from the truck and turn back into the face. With a steering wheel, that all involves a great deal of arm and shoulder motions.

But with joystick steering, production loading is reduced to a series of wrist motions and the task is much less tiring. That’s why Caterpillar only offers its one-lever STIC steer system on the 988, 990, 992, 993, and 994 loaders-the larger models.

The Cat STIC steer system combines the steering, gear selection and direction control into one control lever. One finger selects direction and the thumb selects the gear. The joystick and integrated transmission control reduce the amount of motion required of the operator.

“A more comfortable operator is a more productive operator,” says Jahmy Hindman, product-marketing manager for wheel loaders at John Deere. “We introduced joystick steering with the 844J and made a big splash with it then, and now it’s an option on the 544K through the 824K. We get routine feedback from customers that they’re skeptical at first, but once they try it you can’t get it away from them.”

At Volvo, joystick steering can be optioned on any model. “In the last couple of hours of the work day, the productivity level will stay high with Comfort Drive Control [joystick steering], when you otherwise might see a sharp decrease in productivity without the option,” says Doug Phillips, Volvo’s product manager for wheel loaders.

In April 2009, Case Construction Equipment introduced joystick steering on Case E Series wheel loaders-models 521E through 921E. Case says joystick steering can be used in all gears and all work modes on the machines.

What’s more, Caterpillar offers a reduced-effort steering system on mid-sized loaders. Called Command Control, the system enables the operator to achieve full machine articulation by turning the steering wheel only 70 degrees versus two or more full revolutions with standard steering. Command Control is especially popular with aggregates producers who mainly do truck loading with their wheel loaders, says Caterpillar.

New Track Loader
Caterpillar’s 263-horsepower 973D track loader has a new closed-center, load-sensing implement hydraulic system with a variable-displacement pump that produces only the precise volume of oil actually required for the job at hand.

By contrast, the 973C’s hydraulic pump produced a constant oil volume, whether it was needed or not. The net result is that the 973D pumps less oil, conserves fuel, generates less heat, and frees up horsepower to drive the tracks more efficiently.

In the new operator’s station aboard the 973D, buyers can now choose joystick steering or pedal steering. The steering joystick also provides transmission control, which allows the operator to effortlessly select travel direction and ground speed. The pedal-steer system works in conjunction with the Cat V-pattern transmission controller.

On Deere’s five largest K Series loaders-the 644K through the 844K, the company offers a lock-up, five-speed torque converter. The system provides two benefits, says Hindman. “One is productivity; it will climb grades faster than a standard torque converter machine,” he says. “And the other big benefit is fuel economy. When it locks up, you get a direct drive from the engine to the axles. We see a benefit of 10% to 12% in fuel economy compared to a standard converter in stockpiling and load-and-carry applications.

Also in the K-Series, John Deere embedded a payload weighing scale powered by industry leader Loadrite. “The payload scale was an important item for us,” says David Morrison, a John Deere customer from Aulick Leasing Inc., Rapid City, SD. “The loader we worked with was equipped with one, and it was handy not only in loading trucks correctly, but also because we used the scale with a counter to keep track of our daily production. It’s a big plus.”

All of Deere’s K-Series 4WD loaders include keyless starting systems, seat-mounted controls, expanded sealed switch module and a new color LCD monitor with a multifunction interface. The keyless start feature enables operators to start the loader with the push of a button. It also has a security mode, which prevents unauthorized engine starting until a code is entered on the sealed switch module keypad. Special codes can be set for the owner, operator, and transport.

The LCD monitor provides screen displays of machine parameters, an operator check sheet, real-time fuel usage and extensive diagnostics. “John Deere has designed a new color monitoring system for the operator to have fingertip control over everything that goes on within the cab of the loader, and it’s very easy to use and very operator-friendly,” says Craig Raske, a John Deere customer from Knife River Corp. in Sauk Rapids, MN.

Deere offers load-sensing hydraulics across the entire K Series of loaders. The benefit is fuel efficiency, says Hindman. “You only supply as much oil as the function requires.”

Komatsu offers a complete line of wheel loaders ranging up to the 527-horsepower WA600-6, its largest construction-sized wheel loader. But only the larger models, from the WA380-6 (191 horsepower) and larger, have load-sensing hydraulics.

Deere offers both parallel lift and Z-bar linkages on the 444K model through the 644K loader. And a tool-carrier linkage is offered on the 624K model. “The benefit of parallel lift is that it keeps the load level to the ground through the range of lifting heights,” says Hindman.

The tool carrier linkage is usually supplied with a quick coupler on the front. “You can pick up buckets, forks, jib booms, and more,” says Hindman.

Case Construction Equipment recently released a Case-branded hydraulic quick coupler for its wheel loaders. The new coupler maintains compatibility with current buckets and attachments. The coupler is available as a factory-installed option or as a dealer installation to retrofit machines in the field.

The hydraulic coupler is available for use on Case 521E, 621E, 721E, and 821E wheel loaders and on all configurations of those models. All attachment changes can be done from the seat of the cab. “The hydraulic coupler is manufactured to Case specifications and is fully supported by Case dealers across North America,” says Mitchell Blake, Case brand marketing manager. “Being supported by 375 Case dealers provides our customers with the uptime assurance they expect.”

Volvo’s OptiShift
Volvo’s new OptiShift feature eliminates torque converter losses by means of a lock-up and free-wheel stator. Power in a torque converter is hydraulically transferred from the pump rotor to the turbine rotor and on to the transmission. The engine powers the pump rotor that moves oil to the turbine rotor, thereby turning the turbine rotor. The stator acts as a stationary point for the oil, creating leverage.

That effect reaches its maximum when the engine rotates the pump rotator without being able to initiate turbine rotor rotation. The downside to a torque converter is that the utilization factor drops from the point where the turbine rotor reaches the same rotation speed as the pump rotor.

But with OptiShift, Volvo added a drive clutch that mechanically locks the pump rotator and the turbine rotator. Thus losses are eliminated. An OptiShift transmission offers smooth shifting with automatic lock-up in second, third, and fourth gears. The operator can switch the lock-up function on or off from within the cab.

Volvo says OptiShift reduces fuel consumption, boosts productivity, provides increased operator comfort and better drive response, and improves hill-climbing performance. Decelerations are more comfortable and there is less loading stress on the drive line with OptiShift.

OptiShift also includes Reverse by Braking (RBB) for smooth deceleration. In short-cycle loading it’s common to use the gear shifter to change between forward and reverse without applying the brakes. Deceleration is handled by the torque converter in such cases. However, that method is less efficient than braking, results in energy loss, and places a lot of strain on the converter due to heat transfer.

Volvo’s patented RBB feature automatically assists machine deceleration by using the standard service brake instead of the torque converter. The operator handles the machine the same as before, yet upon deceleration using the forward/reverse lever, RBB recognizes the speed, direction, and throttle position and applies the service brake to slow the machine. This provides smoother deceleration and direction change, and since the converter is no longer used, the machine saves fuel and reduces converter wear.

With a Volvo Automatic Power Shift technology, the operator can change shifting patterns from the seat. There are four forward and four reverse gears in every Volvo wheel-loader model. And Volvo offers a 100% lockable gear-to-gear differential as standard on models from L60F (154 horsepower) to L220F (352 horsepower). The L350F, at 528 horsepower, has a limited slip differential. The machines can be optioned with limited slips front and rear if the customer desires.

Komatsu’s Lineup
Komatsu’s range of wheel loaders includes seven Dash 6 models, from the WA150-6 at 98 horsepower to the WA320PZ-6 at 167 horsepower. That range includes two PZ models, for parallel Z-bar linkage. “It stays parallel to the ground at most bucket angles,” says Mike Gidaspow, product manager for wheel loaders at Komatsu America Corp. “And all PZ models come standard with auxiliary hydraulics and a quick-coupler.”

The PZ linkage has a cast boom cross-tube that improves the operator’s vision so that he can see fork tips, for example. The casting is rounded inward and is optimized for operator visibility. Gidaspow says the PZ linkage provides large tilt forces at all heights and more consistent boom power through the whole operating range, compared to a standard Z-bar.

“We use limited slip differentials as an option on both axles,” says Gidaspow. “We feel that limited slip makes it easy on the operator; he doesn’t have to worry about when to lock the axles. It’s automatic; it activates when it needs to.

“On the 100- to 150- horsepower models we have hydrostatic transmissions,” says Gidaspow. “It’s a one-pump, two-motor system. We really like it because it has excellent travel response, aggressive drive into the pile, and excellent fuel economy.”

With the hydrostatic transmission, Komatsu offers an inching pedal that lets the operator separate power for propulsion from power for the attachment. “You reduce hydraulic flow to the propel motors, and keep your equipment working at full power,” says Gidaspow. “You use the left pedal to slow down your ground speed so that relatively more flow goes to your implement. It’s handy for attachments such as a broom, or in any tight V-shaped loading pattern.”

Plus, the hydrostatic transmission allows Komatsu to use variable traction control to reduce tire slippage on soft ground. Simply stated, the system allows for adjustable tractive effort. It is controlled by a three-stage switch that has an “A” setting for slight traction reduction, a “B” or mid-range setting, and “C,” a minimum setting.

“When you get down to the “˜C’ level, you have reduced tractive effort by about 35%,” says Gidaspow. In addition, Komatsu now offers the low-effort S-mode to provide optimum driving force for operations such as slippery stockpile loading, which extends tire life and improves work efficiency.

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New From Doosan
Just this past April, Doosan Infracore launched the new DL420, an articulated wheel loader with a larger engine than the DL400 it replaces. With the addition of the DL420, the Doosan range of wheel loaders includes eight models with bucket capacities ranging from 1.9 to 6.5 cubic yards.

The DL420 is powered by a 280-horsepower, six-cylinder Cummins diesel with a high-pressure unit injector system and a state-of-the-art combustion system. Emissions are well below the EPA’s Tier 3 limits.
A robust Z-bar boom linkage provides a standard bucket breakout force of 47,210 pounds. The DL420 has four forward speed ranges and three reverse ranges.

A new integrated monitoring system displays information about the loader’s engine and transmission, including service intervals for each filter and the engine oil. The monitoring system also provides service fault codes to the operator without the need to hook up a PC. Codes can then be reported to the dealer’s service technician, saving diagnostic time and reducing expense. In addition, the integrated monitoring system allows the transmission to be tuned by the operator without the assistance of a mechanic.