The last of Caterpillar’s crawler loaders to join the D Series is the largest, the 973D, which hasn’t seen a major update other than engine-emissions upgrades since 2000. Its Cat C9 engine delivers a 10 percent increase in engine horsepower, and the operating weight is 4 percent more than the C Series machine. The hydrostatic loader gets a new closed-center, load-sensing implement hydraulic system with variable-displacement pump to push only the volume of oil actually required for the job at hand, reducing unnecessary flow volume to conserve fuel, reduce heat and smooth simultaneous use of lift, tilt and travel functions. Position-sensing electronics allow operators to set bucket-lift and tilt kick-outs, which can quickly be reset for each job – or even each truck – to speed cycle times. End-of-travel snubbing stops cylinders gently. Buyers can choose pedal steering or joystick steering, with transmission control in the steering joystick. The choice of joystick or two-lever loader controls now mounts the electro-hydraulically actuated controls on the seat so they move with the operator as the seat is adjusted.
September 28, 2010