There is provided a crane including a main body, a tower derrickably supported by the main body, a jib derrickably supported by the tower, an assist member that assist the jib to move along a ground, and a determination unit that determines whether or not the jib is stopped when the tower is lowered in a lowering work state where the jib is assisted by the assist member.

An articulated boom having two limbs, wherein at least one of the limbs includes a first section, a second section and an electrically insulating connecting piece which connects the first section to the second section and which is rigidly connected to the first section and to the second section. The connecting piece includes glass fibers which are cast with a plastic matrix.

A lifting device includes a drive, a speed change gear device arranged above the drive and configured to be rotatable by means of the drive, a transmission device connected to the speed change gear device and a lifting mechanism fixed in the transmission device, and the speed change gear device is fixed to a side wall of the transmission device. Under an action of the drive and a speed change of speed change gear device, a gravity of a weight suspended on the lifting device is converted, so that the weight is lifted under a small force. The lifting device can also be driven via an electric hand tool. In addition, a first transmission device and a second transmission device are provided with a safety device to lock the lifting device when reaching a top, so as to prevent the lifting device from slipping to cause injuries.

A lifting device includes a drive, a speed change gear device arranged above the drive and configured to be rotatable by means of the drive, a transmission device connected to the speed change gear device and a lifting mechanism fixed in the transmission device, and the speed change gear device is fixed to a side wall of the transmission device. Under an action of the drive and a speed change of speed change gear device, a gravity of a weight suspended on the lifting device is converted, so that the weight is lifted under a small force. The lifting device can also be driven via an electric hand tool. In addition, a first transmission device and a second transmission device are provided with a safety device to lock the lifting device when reaching a top, so as to prevent the lifting device from slipping to cause injuries.

Segment of an articulated arm made of composite material, with an elongated shape defining a longitudinal axis, and having a box-like cross section. The segment includes a first end portion, configured for the pivoting of a further segment, a second intermediate portion configured for the pivoting of an actuation member, and a third end portion. The first, second and third portions are made in a single body. The second intermediate portion includes a protruding zone defined by a first side and by a second side converging with respect to each other to define a top. Pivoting elements are provided in the protruding zone for the pivoting of the actuation member between the protruding zone and the first end portion. The first and the second side defining the protruding zone are filleted to substantially rectilinear adjacent tracts of the first and third end portions.

Segment of an articulated arm made of composite material, with an elongated shape defining a longitudinal axis, and having a box-like cross section. The segment includes a first end portion, configured for the pivoting of a further segment, a second intermediate portion configured for the pivoting of an actuation member, and a third end portion. The first, second and third portions are made in a single body. The second intermediate portion includes a protruding zone defined by a first side and by a second side converging with respect to each other to define a top. Pivoting elements are provided in the protruding zone for the pivoting of the actuation member between the protruding zone and the first end portion. The first and the second side defining the protruding zone are filleted to substantially rectilinear adjacent tracts of the first and third end portions.

A double jib slewing pedestal crane includes a main jib and a secondary jib, and a secondary jib positioning device to support and position the secondary jib with respect to the main jib and actuate the pivotal movement of the secondary jib. The secondary jib positioning device includes a secondary jib positioning cable; a spoke structure fixed to the secondary jib and extending radially outward; a tension chain connected at one end to the secondary jib positioning cable and at the other end to the secondary jib and/or to the spoke structure, wherein the spoke structure is adapted to support the tension chain.

A double jib slewing pedestal crane includes a main jib and a secondary jib, and a secondary jib positioning device to support and position the secondary jib with respect to the main jib and actuate the pivotal movement of the secondary jib. The secondary jib positioning device includes a secondary jib positioning cable; a spoke structure fixed to the secondary jib and extending radially outward; a tension chain connected at one end to the secondary jib positioning cable and at the other end to the secondary jib and/or to the spoke structure, wherein the spoke structure is adapted to support the tension chain.

A multi-component lattice mast section comprises a longitudinal axis, a plurality of chord elements extending along the longitudinal axis, a plurality of connection bars interconnecting in each case two adjacent chord elements, a lattice mast cross-sectional surface area with a lattice mast width and a lattice mast height, the lattice mast cross-sectional surface area being oriented perpendicular to the longitudinal axis, and at least two detachably interconnectable lattice mast assemblies, with each of the lattice mast assemblies having a lattice mast assembly width smaller than the lattice mast width and/or a lattice mast assembly height smaller than the lattice mast height, and with the connection bars being firmly connection to a chord element in a working arrangement.

The present invention relates to a lattice piece for a crane boom consisting of a first and a second lattice section element, each comprising a first chord member which extends substantially parallel to the longitudinal direction of the lattice section element, a second chord member which extends substantially parallel to the longitudinal direction of the lattice section element, a first web member which is firmly connected with the first chord member and the second chord member, and preferably extends in the plane defined by the first chord member and the second chord member, wherein a first web member is firmly connected with the first chord member and rises from a plane defined by the first chord member and the second chord member, wherein at its end facing away from the first chord member the second web member includes a fastening means for a releasable connection.