The Manitowoc Story

Manitowoc 6400

Having achieved great success with its 7-yard 4600 excavator, and listening to demands from its American coal stripping customers, Manitowoc introduced the 6400 dragline in 1977. Carrying a 16 cubic yard bucket on a 160-foot boom, its capacity was more than double that of the smaller machine. Like the 4600, the 6400 boasted two engines, but this time one engine was mounted in the lower works to power the propel. The upper engine, a V16 Cummins diesel rated at 1,600 horsepower, drove the hoist and drag through VICON control, and also the swing motion. The lower engine, a Cummins six-cylinder diesel rated at 450 horsepower, provided independent hydraulic drive via gear reductions to each crawler. This engine drove two variable-displacement reversible hydraulic pumps which ran two hydrostatic motors in each crawler assembly, an arrangement that eliminated conventional drive chains and allowed counter-rotation of the crawlers.

The upper machinery included VICON control for hoist and drag as mentioned, but also included hydraulic swing and boom hoist systems. Swing motion was via two hydrostatic motors positioned on opposite sides of the swing gear, each powered by a variable-displacement reversible hydraulic pump. A similar hydrostatic motor and reversible hydraulic pump