A crane for use on an offshore vessel is provided with a boom restrainer, wherein the boom restrainer is a hydro-pneumatic boom restrainer, for reducing upward pivoting of the boom, when the boom is in the top zone, wherein the boom restrainer includes: multiple hydraulic cylinders, each having a hydraulic circuit and a cylinder rod with a cylinder head, wherein the cylinders are mounted on the crane structure with the cylinder heads directed towards the boom of the crane, preferably are mounted on a stay of the crane structure, a catcher for each hydraulic cylinder, wherein each catcher is mounted on the boom and is configured for receiving the cylinder head of the corresponding hydraulic cylinder, and to lock the cylinder head, preferably pivotable locks the cylinder head, relative to the boom, when the boom pivots upwards in the top zone; a gas buffer for each hydraulic cylinder, wherein each gas buffer is mounted to the corresponding hydraulic cylinder, and is connected to the hydraulic circuit of the corresponding hydraulic cylinder via a medium separator, wherein the gas buffer forces the hydraulic cylinder in an extended position, and wherein the volume ratio between the hydraulic cylinder and the gas buffer is such that the hydraulic cylinder acts as a progressive spring, e.g. the gas buffers each have a size in the range of 1000-1400 litre, for example 1200 litre and the hydraulic cylinders each have a size in the range of 800-1000 litre, for example 900 litre, and preferably the ratio between the volume of the gas buffer and the volume of the associated hydraulic cylinder is 4:3.

This dynamic lift-off control device, which is mounted on a crane having a boom and a winch for winding a wire rope and controls dynamic lift-off of a suspended load, comprises: an image-capturing unit that is installed at the tip of the boom and captures an image including a hook; and a control unit that controls a winding action of the winch and a raising action of the boom. The control unit calculates the amount of misalignment between the tip of the boom and the hook on the basis of the image, and feedback controls the raising of the boom to reduce the amount of misalignment, thereby suppressing the swing of the suspended load.

A method for moving a load with a crane in a collision-free manner in a space having at least one obstacle includes providing a position of the obstacle, providing at least one safe state variable of the load, determining from the safe state variable a safety zone surrounding the load, and dynamically monitoring the safety zone in relation to the position of the obstacle.

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.

Provided is a crane (1) including: a boom (7); a wire rope (8); a winch (9); and a hook (10). The crane further includes: a spooling operation instrument (24) for enabling commanding an operation state of the winch (9); and switches (switch (41) or switch (42)) for enabling commanding a switch of a control mode with regard to the operation of the spooling operation instrument (24). When the boom (7) is in a flat travel orientation with the hook (10) loaded on a prescribed site (hook platform (12)), the switches ((41), (42)) being in an on state and the spooling operation instrument (24) being operated toward one side thereof cause the boom (7) to be raised to a work orientation while the wire rope (8) is unwound such that the hook (10) is not lifted.

A control unit of the crane controls drives that move an upper load suspension point and, together therewith, a load suspended via a cable system. As the upper load suspension point is moved, an inner safety zone around the load is repeatedly dynamically determined according to state variables of the crane. The state variables include at least a position and a speed of movement of the upper load suspension point, and an effective pendulum length of the load. The control unit checks, based on further known information whether an object different from the load has entered the inner safety zone, in which case the movement of the upper load suspension point is stopped or a message to stop the movement is outputted to an operator of the crane. Otherwise, the movement is maintained or no message to stop the movement is outputted to the operator.

A control unit of the crane controls drives that move an upper load suspension point and, together therewith, a load suspended via a cable system. As the upper load suspension point is moved, an inner safety zone around the load is repeatedly dynamically determined according to state variables of the crane. The state variables include at least a position and a speed of movement of the upper load suspension point, and an effective pendulum length of the load. The control unit checks, based on further known information whether an object different from the load has entered the inner safety zone, in which case the movement of the upper load suspension point is stopped or a message to stop the movement is outputted to an operator of the crane. Otherwise, the movement is maintained or no message to stop the movement is outputted to the operator,

A lifting device includes a motor designed as a three-phase asynchronous motor via which the lifting device can be driven to lift and lower a load, and includes a brake resistor via which a power output resulting from a motor generator operation that is carried out when lowering the load at a lowering speed can be converted into heat. The brake resistor is designed for a rated power which is less than the power resulting with a nominal load and a nominal speed. A method for operating a lifting device includes lowering a load at a lowering speed while taking into consideration at least one load capacity characteristic value of the brake resistor for the lowering speed, a threshold is set such that while lowering the load at the lowering speed corresponding to the threshold, the resulting power output is limited to the at least one load capacity characteristic value.

A method and system for controlling an actuator, in particular an actuator of a winch, a hoist or a crane, wherein the actuator is controlled using a fail-safe control unit. In order to improve a corresponding method, according to the invention, set point values are calculated in the fail-safe control unit, on the basis of which values the actuator is controlled.

Provided is a crane (1) including: a boom (7); a wire rope (8); a winch (9); and a hook (10). The crane further includes: a spooling operation instrument (24) for enabling commanding an operation state of the winch (9); and switches (switch (41) or switch (42)) for enabling commanding a switch of a control mode with regard to the operation of the spooling operation instrument (24). When the boom (7) is in a flat travel orientation with the hook (10) loaded on a prescribed site (hook platform (12)), the switches ((41), (42)) being in an on state and the spooling operation instrument (24) being operated toward one side thereof cause the boom (7) to be raised to a work orientation while the wire rope (8) is unwound such that the hook (10) is not lifted.