Prefabricated building mobile crane - has chassis and telescopic derricking jib allowing passage through doorways and hydraulic derricking rams

摘要

The crane has an engine-driven hoist drum at one end and a derricking jib at the other. The chassis is narrow enough to allow the crane to drive through a conventional doorway, and the jib (5) is telescopic. The latter derricks between a forward position only slightly inclined to the chassis (1) and a rear one above the hoist drum (2) and drive, so that it can pass under a door lintel. It is actuated by a gantry (8), extending upwards in the working position of the crane and pivoting on the jib at one end. Rams (9) act between gantry and jib to derrick the latter, and there is a further ram (10) between gantry and chassis to bring the gantry back to the rearmost position. The hoist rope is reeved over pulleys (11) at the outer ends of gantry and jib.