Hydraulic excavator with grab suspended from boom - has a rigid longitudinally variable coupling between boom and grab

摘要

The grab is operated by at least one hydraulic cylinder which is linked to the rigid coupling. each such cylinder is connected to a pressure medium source by a longitudinally variable line. The rigid coupling comprises two telescopic tubes moving one inside the other whereby the outer tube is linked to the boom and the inner tube has the grab suspended from its free end. In a design variation the outer telescopic tube is swivelable via an intermediary section about two axes at right angles to one another and is linked to the boom. A hydraulic working cylinder is used to adjust the angle of inclination of the telescopic tubes.