Lorry mounted crane - has main jib ram acting at point slightly offset from centre line

摘要

The crane has a main jib attached to the frame and raised and lowered by a hydraulic ram, with a derricking fly jib at the free end, while alongside the fly jib are extension jib sections. When the main jib is lowered and the fly jib derricked inwards these fit against the side of the crane frame or in an opening in the latter. The ram of the main jib acts on it at a point, when seen from above, which is offset from the jib centre line for between 5 and 15% of the distance for which the extension jib section is offset from this centre line.