CIRCUITRY FOR OPERATING AN EXTENDABLE BOOM AND SERVICE LINE

摘要

A hydraulic circuit for selectively extending and retracting a mobile telescoping boom assembly and for independently extending and retracting an articulated pipe service line mounted on the boom assembly. The circuit can be used with a hydraulic ram to extend and retract the boom assembly or a winch and cable arrangement can be used. A pair of winches are used to extend and retract the articulated service line.