Lorry-mounted crane with telescopic jib - has parallelogram linkage between slewing superstructure and intermediate frame supporting jib

摘要

The crane has a slewing superstructure on which a telescopic jib derricks about a horizontal axis, being raised into the working position and lowered for travelling. The superstructure (3) has a parallelogram linkage (11,12) coupling it to an intermediate frame (13) incorporating the derricking bearing (14) for the jib. The frame is lowered from the working position above the superstructure into the travelling position, typically behind the latter. The crane driving position (22) can be on the frame.