A system for recovering energy from a hydraulic actuator and to a method of operating the system are described. The system may have a hydraulic actuator and a source of hydraulic pressure, comprising a hydraulic pump, in fluid communication with the hydraulic actuator for pressurizing the hydraulic actuator. The system may also have a hydraulic accumulator assembly for selectively absorbing energy from the hydraulic actuator or via the hydraulic actuator. The system may also have a first one-way valve configured to provide fluid communication between the hydraulic actuator and the hydraulic accumulator assembly. The first one-way valve may be configured to permit a flow of fluid through the first one-way valve from the hydraulic actuator to the hydraulic accumulator assembly. The first one-way valve may also be configured to block a flow of fluid through the first one-way valve from the hydraulic accumulator assembly to the hydraulic actuator.

A hoisting system for the installation of a wind turbine wherein said hoisting system comprises measures to achieve a load bearing connection to the tower of the wind turbine and comprises measures to move the hoisting system up and down along the tower wherein the hoisting system, when it is fixed to an already installed part of the wind turbine tower with said load bearing connection, is arranged to install or remove any of a tower segment, a nacelle, a generator, a hub, and a blade in one or more combined hoists or in a single hoist.

A hydraulic crane comprising: a rotatable column (7); a crane boom system comprising a first crane boom (11) connected to the column; and an electronic control device for controlling the movement of the column and the crane boom system on the basis of control signals from a manoeuvring unit and a calculation model for boom tip control. The control device is configured to switch from a first control mode into a second control mode when the first crane boom is about to interfere with an obstacle. In the first control mode, the control device controls the crane boom movements in accordance with an ordinary control strategy. In the second control mode, the control device makes the load suspension point (P) of the crane boom system move along the trajectory defined by said control signals while controlling the crane boom movements in accordance with an auxiliary control strategy in which the first crane boom is prevented from interfering with the obstacle.

The present invention is provided with: a manipulation unit; a winch device that operates with an actuation mode of either a high speed mode or a low speed mode, and winds in or reels out a wire rope; a selection unit for an operator to select either the high speed mode or the low speed mode; a load calculation unit calculating a suspended load; a tension calculation unit calculating the tension of the wire rope; and a control unit controlling the actuation of the winch device. If the mode selected by the selection unit is the high speed mode, the manipulation unit is manipulated from a neutral state to a non-neutral state, and the suspended load is smaller than a load threshold and the tension is smaller than a tension threshold, the control unit controls the winch device so as to operate in the high speed mode.

The present disclosure relates to the technical field of cranes, and in particular to a crane hydraulic control system and a crane. The crane hydraulic control system of the present disclosure includes a prime mover, an execution control mechanism, a hydraulic baking device, a running energy recycling device and an operation energy recycling device. By means of cooperation among the operation energy recycling device, the energy recovery device and the hydraulic energy conversion device, kinetic energy in a driving braking process of the crane and the potential energy in a load lowering process are respectively converted into hydraulic energy for recovery, storage and reuse, therefore, the present disclosure can achieve the recovery of the superstructure energy and the lower vehicle energy of the crane so as to effectively reduce the energy waste.

A crane, a method for assembly of a crane and a method for disassembly of a crane are disclosed. In accordance with the method, a first mast is fixed in a vertical position. A top mast section of a second mast is positioned adjacent to and outside of the first mast. The top mast section is moved vertically upwards, and this movement is guided by a guide system. Then, the top mast section is fixed relative to the first mast at a position which is at a larger vertical distance from the crane base. Then, a first intermediate mast section of the second mast is fixed to a lower end of the top mast section to build up the second mast. Then, the first intermediate mast section is connected to a pivot, and the second mast is pivoted away from the first mast.

A jib assembly includes a support; a jib attached pivotally to the support for pivotal movement of the jib in relation to the support about a horizontal axis; a first linear hydraulic actuator attached to the support for regulating pivotal movement of the jib and for maintaining the jib in a specific position relative to the support; a lever arm attached unrotatably to the jib; and a draw member attached to the lever arm and to the jib; wherein the first linear hydraulic actuator is attached to the lever arm, and the lever arm is arranged to extend in the direction above the jib.

A system and method for retaining a linear actuator on a crane component such as a mast is disclosed. In the system a retaining mechanism is mounted on either a body of the linear actuator or the crane component and a catch is mounted to the other of the body or the crane component. Retraction of a rod of the linear actuator causes a cap on the rod to contact the retaining mechanism, which causes the retaining mechanism to move into a latched configuration securing the linear actuator.

A lifting unit includes a jib foot forming a proximal part of a jib in a service configuration, a counter jib supporting a balancing ballast, a securing part between the jib foot and the counter jib to secure the lifting unit to a mast, and a cylinder connected to the jib foot such that the jib foot is movable between a lowered position and a lifted position. A second cylinder is connected to the securing part.

A handling apparatus for conducting in-field operations such as removing and/or installing wear parts on earth working equipment along a controlled path. The apparatus can include a crane, a joint having three axes of articulation and a tool.