A rotary tower crane with a tower, which carries a jib and a counterjib, with a jib stay being guided from a tower top to the jib and to the counterjib. The jib stay tensions only an inner jib portion, the length of which is less than 40% of the total length of the jib, and an outer portion, the length of which is more than 60% of the total length of the jib, forms an untensioned bending beam jib which includes at least one jib piece which tapers in height and which is adjoined on the inner side by at least one jib part of greater height and on the outer side by a jib piece of smaller height.

A method of erecting a wind power installation which has an aerodynamic rotor having rotor blade connections. A lifting beam having a ballast unit is fixed to a crane hook of a crane. A rotor blade is fixed to a second crane hook at an underside of the ballast unit by means of lifting cables. The lifting beam and the rotor blade are lifted by the crane for mounting the rotor blade at one of the rotor blade connections.

A method of erecting a wind power installation which has an aerodynamic rotor having rotor blade connections. A lifting beam having a ballast unit is fixed to a crane hook of a crane. A rotor blade is fixed to a second crane hook at an underside of the ballast unit by means of lifting cables. The lifting beam and the rotor blade are lifted by the crane for mounting the rotor blade at one of the rotor blade connections.

A rotating tower crane for erecting a wind turbine, having a tower and a tower substructure, which is connected to the tower and is intended for supporting the tower, wherein the tower substructure has a supporting cross frame, which has three or more, preferably four, legs, extending from the tower. It is proposed that each leg has fastened on it, on the ground side, a load-distributor plate, which is not connected to the foundation, wherein the load-distributor plates together form the ballast of the tower.

A rotating tower crane for erecting a wind turbine, having a tower and a tower substructure, which is connected to the tower and is intended for supporting the tower, wherein the tower substructure has a supporting cross frame, which has three or more, preferably four, legs, extending from the tower. It is proposed that each leg has fastened on it, on the ground side, a load-distributor plate, which is not connected to the foundation, wherein the load-distributor plates together form the ballast of the tower.

Disclosed is a mobile articulated crane having a boom for carrying a load when the crane is stationary and while the crane is mobile. The boom has an end for engaging with a load and an opposed end. The crane further comprises a counterweight attached to the boom at or close to the opposed end of the boom. A rear body of the crane can comprise first and second rear axles, each for supporting the rear body on the ground. The first rear axle can be arranged to be displaced relative to the second rear axle such that wheels of the first rear axle selectively engage or disengage with the ground.

Disclosed is a mobile articulated crane having a boom for carrying a load when the crane is stationary and while the crane is mobile. The boom has an end for engaging with a load and an opposed end. The crane further comprises a counterweight attached to the boom at or close to the opposed end of the boom. A rear body of the crane can comprise first and second rear axles, each for supporting the rear body on the ground. The first rear axle can be arranged to be displaced relative to the second rear axle such that wheels of the first rear axle selectively engage or disengage with the ground.

Ballast for operating machines, having a portion removably couplable to a hooking seat of the operating machine, characterized by having a fixed part is provided. The couplable portion, a movable part and means for constraining the movable part to the fixed part at a plurality of distinct (D, D, D) distances from the fixed part are provided, so as to change the center of gravity position of the operating machine.

Disclosed is a mobile articulated crane having a boom for carrying a load when the crane is stationary and while the crane is mobile. The boom has an end for engaging with a load and an opposed end. The crane further comprises a counterweight attached to the boom at or close to the opposed end of the boom. A rear body of the crane can comprise first and second rear axles, each for supporting the rear body on the ground. The first rear axle can be arranged to be displaced relative to the second rear axle such that wheels of the first rear axle selectively engage or disengage with the ground.

Disclosed is a mobile articulated crane having a boom for carrying a load when the crane is stationary and while the crane is mobile. The boom has an end for engaging with a load and an opposed end. The crane further comprises a counterweight attached to the boom at or close to the opposed end of the boom. A rear body of the crane can comprise first and second rear axles, each for supporting the rear body on the ground. The first rear axle can be arranged to be displaced relative to the second rear axle such that wheels of the first rear axle selectively engage or disengage with the ground.