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.
Hydraulic Excavator Control System
Sae Technical Papers
National Farm, Construction, Industrial Machinery, Powerplant Meeting ; 1972
1972-02-01
Conference paper
English