Telescopic jib for stationary or mobile cranes

摘要

The jib has a hydraulic cylinder unit with a cylinder (26), the movement of which is linked to that of a rope drive connected to the main jib section (1) and to the hydraulic cylinder unit. The end points (24',25') of the extending and contracting ropes (28,27) of the rope drive are connected to a fixing device (18), which is displaceable along the cylinder. The fixed point (25) of the extending rope is arranged at the inner end of the main jib section. The fixed point (24) of the contracting rope is arranged at a distance from the main jib section, which corresponds to the centre of the individual length of the telescoping jib sections (2-5). Rope drive pulley wheels (23,29) are located at least at the head and foot of the cylinder. The extending pulley wheel is multi-grooved.