The invention relates to a method of manufacturing a tower (2) for an offshore wind turbine as well as such a tower. The method comprises providing the tower, mounting a crane (5) to an outer surface of the tower, and transporting the tower to the installation site of the wind turbine after the mounting of the crane. The crane comprises a base part (6) fixedly mounted to the tower, and a crane arm (7) pivotally connected to the base part at a first end (8). The method may further comprise a step of testing and certifying the crane according to a predetermined standard before the step of transporting the tower to the installation site. By application of the invention, the amount of installation work to be performed at the installation site can be minimized. In some embodiments of the invention, the crane arm has a shape matching the outer surface of the tower.

Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

Various embodiments of the teachings herein include methods for controlling a crane. The method may include: acquiring a first speed of a first motor pulling a first end of a hoist; acquiring a second speed of a second motor pulling a second end of the hoist opposite the first end; acquiring a first speed difference between the first speed and the second speed; acquiring a first speed difference threshold; and if the first speed difference is smaller than the first speed difference threshold, sending a control instruction to the first motor to increase a torque output value of the first motor in the trolley traveling direction.

Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

The invention relates to a method and a construction and/or a materials-handling machine for guiding and moving a working head, in particular a 3D print head, wherein at least three revolving tower cranes are attached to each other with their booms, wherein according to one aspect of the invention a guide beam carrying the working head is attached to at least two trolleys of two revolving tower cranes, and the working head is adjusted and moved in its working position by moving the trolleys along two booms of two revolving tower cranes.

Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

Tower crane (1) comprising a tower (2) on which a rotating portion (3) is pivotally mounted and configurable between a service configuration in which the rotating portion can be rotatably driven by means of a motorized orientation system (40), and an out of service configuration in which the rotating portion is rotatably released to be able to be oriented in the direction of the wind, where a control/command unit (5) activates a monitoring mode in the out of service configuration to detect, depending on variations in the angle of orientation or the angular speed of the rotating portion, if the rotating portion is in one of the following instability states: an autorotation state corresponding to a rotary movement of the rotating portion in a given direction over at least one complete turn; or an oscillation state corresponding to a back and forth movement of the rotating portion about the orientation axis.

A marine knuckle boom crane includes a pedestal and a crane housing rotational relative to the pedestal. A knuckle boom assembly is attached to the crane housing and includes a main boom and a spreader type jib. A hoisting system includes a first departure sheave and a second departure sheave on the jib, and a third departure sheave mounted to the main boom or to the crane housing. One or more winches drive a first, second, and third cable which are each connected to an object suspension device and each pass via the first, second, and third departure sheave, respectively, to the respective winch. The first, the second, and the third cable together define an inverted pyramid which diverges upwards from the object suspension device when handling the object.

A tower crane includes a tower on which a rotating portion is pivotally mounted and configurable between a service configuration in which the rotating portion can be rotatably driven by a motorized orientation system, and an out of service configuration in which the rotating portion is rotatably released to be able to be oriented in the direction of the wind. A control/command unit activates a monitoring mode in the out of service configuration to detect, depending on variations in the angle of orientation or the angular speed of the rotating portion, if the rotating portion is in one of the following movement states: an autorotation state corresponding to a rotary movement of the rotating portion in a given direction over at least one complete turn; or an oscillation state corresponding to a back and forth movement of the rotating portion about the orientation axis.