Caterpillar's D7E track-type tractor, with its diesel-electric powertrain, has "proved its ability to deliver reliable, low-cost production in a range of applications" since its introduction, says Cat. The D7E uses 10 to 30% less fuel and, on average, moves 10% more material per hour than its predecessor, the Cat D7R. The new D7E waste-handler version is said to blend the efficiency of the D7E with features that allow it to take on harsh landfill applications with best-in-class performance, durability, and economy.
The electric-drive powertrain is said to be particularly well suited to waste-handling operations, "applying engine power to the tracks in a smooth, steady manner that yields exceptional traction and lugging ability in poor underfoot conditions." The waste-handler D7E also delivers improved maneuverability characteristics by employing a Cat-designed differential steering system driven by a D8-size steering pump. The new drivetrain allows gradual full-power turns, locked-track pivot turns, and counter-rotation.
Overall, the waste-handler D7E has a fuel economy and productivity that allows it to achieve a fuel-efficiency rating (material moved per gallon/liter of fuel) that typically is 25% higher than machines in the same size class with conventional drivetrains. Its improved fuel economy, reduced fluids, and fewer mechanical components enables the machine to consume fewer resources, while doing more work than a conventionally designed machine.
Extreme-service guarding helps protect the waste handler from hostile environments. Heavy-duty bottom guards protect the crankcase and drivetrain components, while also preventing trash buildup. Easy access to the powertrain is achieved via a hinged design.
A heavy-duty radiator guard shields the D7E's three-section cooling system. A new dual-hinge design allows the guard to fold away completely for easy cleaning access—without removing the lift cylinder. The new system (engine, propulsion module, and charge-air cooling) is designed as a single plane, eliminating a stacked arrangement of individual coolers that could trap debris. Wider radiator-fin spacing (six per inch) lets small debris pass through, and an automatically reversing hydraulic fan purges debris from the coolers and perforated engine enclosures.
Specially designed guards prevent damage to pivot-shaft seals. Chassis guards protect the engine-compartment side panels from damage by deflecting debris.
A newly designed final-drive-seal guard prevents potentially damaging flexible trash, such as wire and nylon strapping, from wrapping around the duo-cone seal area. The new guard includes a rugged cast outer shell to resist abrasion, plus multiple labyrinth seals and an inner Kevlar seal.
Guards for the front-idler seals are similar, incorporating a labyrinth design that keeps debris out. Optional front and rear striker bars prevent trash from riding up the tracks and damaging the fenders, fuel tank, or hydraulic tank—all of which are also equipped with special guards.
Laminated thermal shields cover the exhaust manifold, hot side of the turbocharger, and the exhaust stack within the engine compartment. These shields reduce surface temperatures well below the flash point of most combustibles in waste-handling operations. A two-stage, intake-air precleaner has a spinning impeller that ejects most debris, and remaining contaminants are removed by a secondary exhaust scavenger before intake air reaches the main filter, providing exceptional air-filter life.
Lights are positioned on the D7E waste handler for the most efficient lighting pattern, says Cat, and the ROPS-mounted air-conditioner condenser is positioned above swirling dust and debris. Added sealing is used for engine enclosures, operator-station platform, battery box, and rear-case opening to keep out even fine debris.
Options for the waste handler include front and rear striker bars and center-hole track shoes, which allow the sprocket to punch out debris that might otherwise collect in the track chains and accelerate wear. An enhanced cab, with higher pressurization, a powered precleaner, and high-efficiency filter, keeps air in the operator's station cleaner. Available rear-mounted work tools include a multishank ripper, winch, or drawbar.
Blade types for the standard-gauge undercarriage include the universal, semi-universal, and straight—all available with a trash rack for increased capacity and added machine protection. Machines with the optional low-ground-pressure undercarriage use a larger-capacity straight blade with a trash rack. All waste-handler blades are faced with a 3/8-in (10-mm) thick steel wear plate for added durability.
The optional D7E waste-handler's SystemOne undercarriage features sealed and lubricated cartridges, eliminating pin-and-bushing turns, and sprockets designed to last the life of the track chain. Both undercarriage types currently are available in either standard or LGP gauge; all appropriate blade options also are currently available.