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 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 crane having a luffing jib and a lifting cylinder includes a cylinder body and a movable rod hinged on the jib to raise and lower the jib, and a locking device adapted to cooperate with the lifting cylinder to mechanically lock the rod in a deployed holding position and block the jib in a raised holding configuration, and further including a spacer hinged on the jib and supporting an abutment, the spacer configured for pivoting between a release position wherein the spacer is offset, authorizing the movable rod to be displaced freely, and a locking position wherein the spacer is folded so that the abutment is able to bear on the cylinder body to fixedly maintain the movable rod in the deployed holding position.

A crane having a luffing jib and a lifting cylinder includes a cylinder body and a movable rod hinged on the jib to raise and lower the jib, and a locking device adapted to cooperate with the lifting cylinder to mechanically lock the rod in a deployed holding position and block the jib in a raised holding configuration, and further including a spacer hinged on the jib and supporting an abutment, the spacer configured for pivoting between a release position wherein the spacer is offset, authorizing the movable rod to be displaced freely, and a locking position wherein the spacer is folded so that the abutment is able to bear on the cylinder body to fixedly maintain the movable rod in the deployed holding position.

A crane includes a luffing jib and a lifting cylinder having a cylinder body and a movable rod hinged on the jib to displace the jib in lifting motion and in lowering motion, and a locking device adapted to cooperate with the lifting cylinder to mechanically lock the rod in a deployed holding position and block the jib in a raised holding configuration. The crane further includes a spacer hinged on the jib and supporting a stop, the spacer pivotable between a release position in which the spacer is shifted, allowing the movable rod to be freely displaced, and a locking position in which the spacer is folded so that the stop is capable of abutting on a bearing surface in a ball jointed connection with the cylinder body, to fixedly hold the movable rod in the deployed holding position.

A crane includes a luffing jib and a lifting cylinder having a cylinder body and a movable rod hinged on the jib to displace the jib in lifting motion and in lowering motion, and a locking device adapted to cooperate with the lifting cylinder to mechanically lock the rod in a deployed holding position and block the jib in a raised holding configuration. The crane further includes a spacer hinged on the jib and supporting a stop, the spacer pivotable between a release position in which the spacer is shifted, allowing the movable rod to be freely displaced, and a locking position in which the spacer is folded so that the stop is capable of abutting on a bearing surface in a ball jointed connection with the cylinder body, to fixedly hold the movable rod in the deployed holding position.

An installation jib for a girder beam installation and removal system includes a main body having a first end and a second, opposite end, the main body extending along a longitudinal axis between the first end and the second end. The installation jib further includes a first sub-frame element coupled to the main body, a first roller coupled to the first sub-frame element, a second sub-frame element coupled to the main body, and a second roller coupled to the second sub-frame element. The first sub-frame element and the second sub-frame element are spaced longitudinally apart from one another, and the first roller and the second roller each are configured to rotate about an axis that is parallel to the longitudinal axis.

An installation jib for a girder beam installation and removal system includes a main body having a first end and a second, opposite end, the main body extending along a longitudinal axis between the first end and the second end. The installation jib further includes a first sub-frame element coupled to the main body, a first roller coupled to the first sub-frame element, a second sub-frame element coupled to the main body, and a second roller coupled to the second sub-frame element. The first sub-frame element and the second sub-frame element are spaced longitudinally apart from one another, and the first roller and the second roller each are configured to rotate about an axis that is parallel to the longitudinal axis.

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.