Abstract: It is known to construct various types of cranes such as swing-boom cranes employing extendable boom sections and hammerhead cranes with rotating, counter-balanced, cantilevered booms so that conduits extend between and are connected to parts of such cranes which are movable. Such structures may be improved by using as the conduit a plurality of rigid conduit sections connected together by rotary joints permitting said conduit sections to be rotated about parallel axes. Certain of these joints are located where the conduit is connected to parts of the crane. A rotary joint is also located between each adjacent connection of the conduit to the crane. The sections are dimensioned so that during operation of the crane the rigid sections cannot be moved so as to be aligned with one another. As a consequence of this the various portions of the conduit will fold in a desirable manner as the crane is operated.