Electrohydraulic Control of Aerial Lifts with Nonconductive Push-Pull Cables 730070
Because of the unique control characteristics of electrohydraulic proportional valves-smooth acceleration and deceleration, and the ability to inch or feather the work platform into position-several methods have been devised to use electrohydraulic valves to control electrically insulated aerial lifts.
Since all components bridging the insulated portions of the boom structure must have an insulating value equivalent to the boom itself, it is not permissible to run electrical control cables from the work platform down the insulated boom to the control valves mounted on the chassis below.
Systems using radio signals and light signals (via fiber optic bundles) are being developed to control the more complex, multifunctional aerial lift boom structures.
This paper describes a relatively simple mechanical control system which bridges the insulated portion of the boom with nonconductive, flexible push-pull cables, and which was developed primarily for use on smaller, less complex aerial lifts.