B66C 23/545

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 {with pneumatic or hydraulic motors, e.g. for actuating jib-cranes on tractors with arrangements for avoiding dead centre problems during cylinder motion}