Hydraulic Excavator Control System

The use of a low-pressure, low-volume pneumatic pilot system and amplifiers provides superior control of the dipper and dipper arm of a hydraulic hoe when used in conjunction with pressure-compensated four-way hydraulic valves. The use of a split-control regulator and pilot valve provides automatic proportioning of flow for simultaneous operation of a tilt with extend or dig functions. Since the position of the control lever represents a given flow, regardless of the hydraulic load, an operator can positively proportion the speed of the dipper and dipper arm cylinders.