with jibs the effective length of which is variable in operation, e.g. longitudinally displaceable, extensible

Cranes comprising essentially a beam, boom or triangular structure acting as a cantilever and mounted for translatory or swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib cranes, derricks or tower cranes > with jibs the effective length of which is variable in operation, e.g. longitudinally displaceable, extensible

Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes (base supporting structures with legs B65C5/00) > with jibs the effective length of which is variable in operation, e.g. longitudinally displaceable, extensible