New tracked loader from Cat
By Becca Durrant29 January 2010
Caterpillar has introduced the 973D tracked loader featuring load-sensing hydraulics, joystick steering, a new operator's station (with tilting cab) and + 10 % more power than its 973C predecessor.
The company said like the 973C, the new 28 tonne model is an "all-purpose performer" and retains similar design features, including a Cat C9 engine, hydrostatic drive, single-fabrication mainframe, Z-bar loader linkage and oscillating undercarriage.
The 973D's new closed-centre, load-sensing hydraulic system uses a variable-displacement pump which tailors oil production for different applications. By contrast, the 973C's hydraulic pump produced a constant oil volume, whether it was required or not.
Pumping less oil, the new machine therefore saves fuel, generates less heat and frees up horsepower to drive the tracks more efficiently.The new system also allows seamless, simultaneous use of lift, tilt and travel functions, Caterpillar stated.
The 973D features either joystick or two-lever control systems and although the 973C offered this too, the loader controls for the new 973D are seat-mounted and electro-hydraulically actuated. Previously, they were console-mounted and pilot-actuated (hydraulically assisted). The new seat-mounted, low-effort controls move with the operator as the seat is adjusted, transmit less vibration and provide extremely fast, precise hydraulic response, Caterpillar stated.
Meanwhile, the new cab is sound-suppressed, sealed, pressurised, air-conditioned, resiliently mounted and tilts 30° in the field for access to major components. An increased glass area improves visibility and the new fender design offers sharper sightlines out the rear window.
A new compact dashboard includes both a gauge cluster that monitors vital systems and the Messenger display screen, which provides real-time performance and diagnostic information.
The new machine is equipped with an 8.8-litre, 196 kW Cat C9 diesel engine, which meets Tier 3 (Stage IIIA) engine emissions regulations. The engine also uses Caterpillar ACERT technology for improved emissions control and fuel economy. A new on-demand, viscous clutch cooling fan helps further lower fuel consumption and sound, the company added.
Cat said the electronically controlled Cat Hystat hydrostatic drive system powers and controls each track independently via a variable displacement pump and motor. The Hystat system allows both tracks to be powered through gradual turns, simplifies straight-line travel when working across slopes and provides "exceptional" manoeuvrability with its counter-rotation capability.