The new 156,043-pound (70,780 kg) Cat 374D hydraulic excavator showcased at Bauma 2010, a direct replacement for the model 365C, combines added horsepower, stronger hydraulics, new buckets and greater operating weight to boost trenching, loading and lifting capabilities.
Complementing these design basics are undercarriage improvements, operator-convenience features, safety enhancements and serviceability improvements. The new fuel-efficient 374D is designed to deliver reliable, low-cost operation and long-life durability for optimum customer value, according to Cat.
More power, capable hydraulics
Rated at 476 horsepower (355 kW), the 374D’s Cat C15 ACERT engine produces 18 percent more power than does its 365C predecessor. The C15 engine features advanced electronic control, precise fuel delivery and refined air management for optimum performance, fuel-efficiency and emissions-compliance, the manufacturer says.
The C15’s torque characteristics allow the engine to deliver full power at maximum rpm, resulting in efficient hydraulic-pump operation and enhanced hydraulic response.
A titanium-alloy compressor wheel in the C15’s turbocharger increases reliability and performance at higher altitudes, and the hydraulically driven, variable-speed cooling fan reduces engine load and saves fuel, according to Cat.
The 374D’s implement hydraulic system provides a 10-percent percent increase in hydraulic flow, with a similar resulting gain in hydraulic horsepower. The added hydraulic power combines with larger digging-arm and bucket cylinders to yield 17 percent higher digging forces with the standard (reach) boom-and-arm configuration. For 374D units equipped with the mass-excavation configuration, a larger digging-arm cylinder increases force by 17 percent.
Also new in the 374D’s implement hydraulic circuits are electrically controlled regeneration valves, which assure positive response from the boom and digging-arm cylinders. The resulting benefits include shorter cycle times and estimated fuel savings of more than 2 percent.
Buckets, undercarriage, serviceability
A new line of buckets for the 374D are designed for added strength and durability to accommodate the higher digging forces of the new machine. Bucket types include models for general duty, heavy duty, severe duty and extreme duty. Work tools for the 374D extend the machine’s application into such operations as demolition, scrap processing and quarry work.
Undercarriage improvements include redesigned track links that operate with less stress, forged idlers for improved durability, improved carrier-rollers and a 6-inch (160-mm) track- gauge increase to promote added stability. In addition, the carbody (the structure mounting the machine upper to the track assemblies) has been reinforced at the track-frame interface. For added protection, heavy-duty guards enclose the bottom of the machine.
To facilitate routine maintenance, the 374D provides protected fluid-drain ports and self-contained hoses, spin-on filters, integral pre-cleaner in the air cleaner (with electronic restriction sensing), testing ports in all pressure circuits and pressurized fluid-sampling ports to assure reliable samples. Cooler cores provide ample clearance for cleaning,
Also, the Electronic Power Control is now located in the air-cleaner compartment, allowing the cab floor to be washed without risk of damage to the EPC, although the EPC and electrical terminals are weather-proof. For the operator’s convenience, fluid levels can be checked electronically at start-up.
Operator comfort and safety
For the operator’s convenience and comfort, the height of the joystick consoles is now adjustable, and the response of the joystick control levers can be adjusted to the operator’s preference through the monitor. The control-pattern changer allows operators to select preferred lever functions.
The monitor provides a full-color graphic display with comprehensive machine information (including fuel-consumption) presented in either an English or ISO format. The monitor also displays images from the optional rear-view camera.
To diminish heat and noise in the cab, the hydraulic control valve, pumps and reservoir are positioned away from the operator’s station. Metal-grating catwalks, 20 inches (500 mm) wide, are located on each side of the upper structure to provide safe access to maintenance points. The rear window, made of tempered glass, can be removed as a secondary exit.
Standard halogen lights provide exceptional jobsite illumination, but can be replaced with optional High Intensity Gas lights on the boom, and upper cab if more illumination is required. Lights are time-delayed to allow safe exit from the machine at night. As an added safety measure, travel, swing and implement functions are locked out when the counterweight-removal system is activated.
Operating weight 156,043 lb (70,780 kg) 145,000 lb (66 000 kg)
Engine power 476 hp (355 kW) 404 hp (302 kW)
Maximum dig depth 31.7 ft (9.65 m) 31.0 ft (9.64 m)
Drawbar pull 110,700 lb (493 kN) 111,280 lb (495 kN)
For the official press release from Cat and for photos, go to http://www.cat.com/cda/files/2110201/7/87PR10%20374D%20HEX.doc?mode.