DOOSAN is continuing to extend and enhance its range of large wheel loaders with the launch of the new DL420, which replaces the DL400.

With a bucket capacity of 4 cu m, the DL420 is designed to offer exceptional performance in terms of ease of handling, power, serviceability and durability, says a spokesman for Doosan, adding that other key features include more productivity at lower cost, reliability, comfort and ease of maintenance.

It is intended to meet a wide range of material-handling needs, from loading and transporting granular material (such as sand and gravel) to industrial, mining and quarrying applications. With the addition of the DL420, the Doosan range of articulated wheel loaders includes eight models with bucket capacities from 1.5 to 5 cu m.

Power and performance
The 22.3-tonne DL420 loader is powered by the 10.8-litre, six-cylinder turbocharged Cummins QSM11 electronically-controlled engine with high-pressure unit injector system and a state-of-the-art combustion system. Emissions are well below Phase Three regulatory limits and fuel consumption is about seven per cent less when compared to the DL400.

The engine develops 209 kW (284 HP) at 2,000 rpm and offers a maximum torque of 148 kg.m at 1,400 rpm for optimal traction and breakout force in loading-transport-handling applications.

“Breakout force is among the highest in its category at 210 kN, an important feature for a machine of this Z kinematic class, providing a higher stripping force when working in the hardest materials,” the spokesman says.

Two working modes (standard and economical) are available to optimise the consumption/productivity ratio and adapt the loader to the work at hand.

There are four forward travel speed ranges – up to a maximum of 6.5, 12.4, 18.4, and 38 km per hour – and three travel speed ranges backwards (maximum speeds of 6.5, 12.4 and 18.4 km per hour).

“Thanks to the powerful Cummins engine, the DL420 offers fast acceleration and is able to reach 90 per cent of the maximum speed in 2.3 seconds,” the spokesman continues. “The larger engine also is designed to provide increased durability and a longer service life.”

The DL420 offers a static tipping load with bucket of 18.9 tonnes (at maximum reach with a straight frame) and a height at bucket pivot point of 4.35 m.  Equipped with a pin-on bucket with teeth and tipped forward at 45 degrees, the loader’s dump height is 2.96 m and the dump reach is 1.4 m. The turning radius at bucket edge is 6.995 m at the maximum steering angle of 40 degrees.

Reliability
Like all Doosan wheeled loaders, the DL420 uses a Powershift ZF transmission with limited slip differentials (ZF).
The primary brakes are hydraulically controlled, multi-disc wet brakes.

Special attention has been given to the design and construction of the DL420. “To ensure a long service life to the main structural components, including the chassis, lift arms and articulations, Doosan uses finite element methodology and state-of-the-art computer-aided design techniques. Using computerised modelling, they are subjected to intensive laboratory and field tests in which extreme conditions are simulated and tested,” he says.

Operator comfort
“Operator comfort and convenience were given high priority when the DL420 was designed. Improved visibility, air-conditioning, more room, a very comfortable seat, and ample storage space are all features which enable operators to work for more hours with less fatigue. The noise level in the cab is a comfortable 71.2 dB (A) while the external sound level is 104.7 LwA,” he adds.

New features contributing to operator convenience include an integrated monitoring system, vehicle control unit (VCU) and an optional electric steering system. The integrated LCD panel displays information about the loader, engine and transmission, including the service intervals for each filter and the engine oil. 

The transmission can be tuned by the operator without the assistance of a mechanic. For its part, the VCU optimises performance by controlling engine, transmission and hydraulic system variables.

Other features contributing to operator comfort are a third hydraulic control valve to use the most complex attachments and anti-pitch control, the spokesman says.

Available as an option is a system using a single lever for the control of travel functions and front-mounted attachments.

Ease of maintenance
According to the spokesman, the Doosan DL420 wheel loader is designed to be economical both from the standpoints of use and maintenance.

To reduce fuel consumption and noise, the variable fan speed is controlled by a thermostat. The fan is reversible and tilts in order to facilitate maintenance in dusty environments. There are also large covers for service access from the ground.
Intervals between oil changes and filter replacement have been lengthened, as for the other Doosan loaders. Transmission status is easily verified and various adjustments such as compensation for disc wear are done automatically with no disassembly required.