One rope or two?

摘要

Most manufacturers include "motor" grabs in their portfolio, with the majority of these relying on a cable power feed from the crane to supply an electrical motor, which in turn powers a hydraulic power pack to feed the hydraulic cylinders mat open and close the clam shells or cactus grab segments. While such additional machinery means added complication, cost and tare weight, this type of grab can be hooked onto a single rope crane, plugged in to an appropriate power source and set to work. The design of these hydrauli-cally closing grabs also makes them suitable for modification for the range of hydraulic arm grab cranes, based on mobile excavator technology, produced by companies such as Mantsinen, MultiDocker, Sen-nebogen, Liebherr and Terex Fuchs, which are marketed as a more productive option to rope type jib cranes. As these designs are hydraulically powered, it is a relatively simple matter to dispense with the power pack and couple the grab directly to the cranes main hydraulic circuit.