With a bucket capacity of 5.2 yd3 (3.9 m3), Doosan says the DL420 can take on a wide range of material-handling tasks from loading and transporting granular material (such as sand and gravel) to industrial, mining, and quarrying applications. With the addition of the DL420, which replaces the DL400, the Doosan range of articulated wheel loaders includes eight models with bucket capacities from 1.9 to 6.5 yd3 (1.5 to 4.9 m3).
The 49,163-lb (22,300-kg) DL420 is powered by a 10.8-L, six-cylinder turbocharged Cummins QSM11 electronically controlled engine with high-pressure unit injector system and a state-of-the-art combustion system.
The engine develops 280 hp (149 kW) at 2000 rpm and offers maximum torque of 1070 lb·ft (1450 N·m) at 1400 rpm for optimal traction and breakout force in loading-transport-handling applications.
Depending on the application, operators can choose between two working modes (standard or economy) for either maximum productivity or minimum fuel consumption.
A robust Z-bar lifting system provides a standard bucket breakout force of 47,210 lb (21,414 kg), among the highest in its size class, says Doosan, resulting in higher stripping force and greater productivity when working in hard materials.
The DL420 offers four forward speed ranges with maximum speeds of 4, 7.7, 11.4, and 23.6 mph (6.4, 12.4, 18.3, and 37.9 km/h) and three reverse speed ranges with maximum speeds of 4, 7.7, and 11.4 mph (6.4, 12.4, and 18.3 km/h). The Cummins Tier 3 engine enables the DL420 to accelerate to 90% of maximum speed in 2.3 s. The larger engine is also designed to provide increased durability and a longer service life.
With a 5.2-yd3 (3.9-m3) bucket, the DL420 has a static tipping load of 39,432 lb (17,890 kg) at maximum reach with a straight frame and a height-at-bucket pivot point of 14.25 ft (4.3 m). Equipped with a pin-on bucket with bolt-on cutting edge, tipped forward at 45°, the dump height is 10.2 ft (3.1 m) and the dump reach is 4.2 ft (1.3 m).
The turning radius at bucket edge is 22.9 ft (6.9 m) at the maximum steering angle of 40°.
Like all Doosan wheel loaders, the DL420 features a full powershift transmission with manual and automatic modes. Standard limited slip differentials on both the front and rear axles ensure positive traction in wet or soft conditions.
Hydraulically controlled, multiplate wet disc brakes and dual brake circuits provide positive braking power. A spring-applied/hydraulically released parking brake is mounted on the transmission shaft to prevent the loader from rolling after engine shutdown. An optional electric-powered emergency steering system backs up the hydraulic power steering system in case of a malfunction, and a safety device prevents starting the engine when not in neutral.
Doosan says the DL420 offers operators improved visibility and lower cabin sound levels. Its heating and air-conditioning system, roomier cabin, ample storage space, and comfortable seat also help to reduce operator fatigue. Anti-pitch control provides smoother travel with a loaded bucket. Available as an option is a single lever control for travel functions and front-mounted attachments.
An integrated monitoring system displays engine and transmission information, 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. The integrated monitoring system allows the transmission to be tuned by the operator without the assistance of a mechanic.
The DL420 also features a vehicle control unit that optimizes loader performance by controlling engine, transmission, and hydraulic-system variables.
Contributing to the loader's reduced fuel consumption and lower noise levels are a hydraulically driven, variable speed engine fan with an electronic thermostat that constantly monitors engine coolant and transmission oil temperatures. The fan direction can be reversed from the cabin to quickly clean out the radiator in dusty environments. Also, the hydraulic fan swings out to easily clean the cooler group.
All routine maintenance on the DL420 can be performed from ground level. Centralized hydraulic check ports and easily accessible drain valves for engine oil and coolant simplify routine maintenance. Remote greasing lubrication ports allow front pins to be lubed from the outside of the machine. The transmission oil filler pipe is located near the articulation joint for easy access, and sight gauges for hydraulic oil and coolant levels allow easy daily checks while reducing the risk of contaminants entering the systems.