The present disclosure relates to an apparatus and to a method for controlling a crane slewing gear. The apparatus comprises a hydraulic motor for driving the slewing gear and for braking the slewing gear from a rotational movement. The slewing gear is kept stationary via a holding brake. A hydraulic brake circuit for controlling the holding brake, a load sensing device for measuring a load instantaneously taken up by the crane, and an orientation sensing device for measuring an instantaneous orientation of the crane and/or of at least one crane component are furthermore provided. In accordance with the disclosure, a hydraulic limitation circuit is provided by means of which a hydraulic pressure applied to the motor can be limited to a specific limit value. A control unit is furthermore provided that determines a maximum permitted torque and/or a parameter derived therefrom for a current slewing gear movement.

A rope hoist, which comprises a rope drum for a hoisting rope to be winded thereon and a rope drum cover for partially surrounding the rope drum. Visually observable or readable means for detecting winding/unwinding positions of the hoisting rope on the rope drum are arranged on the rope drum cover, and to indicate lifting height of a load attached to the hoisting rope.

Personnel working at elevated positions use safety lines to prevent falls. Equipment being used in proximity to the personnel may interfere with the safety lines presenting a potential hazard. A fall protection monitor provides an automated and wireless sensor system for avoiding interactions between equipment and safety lines. The fall-protection monitor includes a first sensor for monitoring whether a safety line is in operation. A second sensor monitors a location of a moveable device being used in the vicinity of the safety line. A controller determines the location of the moveable device and whether the safety line is in operation. The controller prevents movement of the moveable device within a predetermined distance from an operational safety line.

The disclosure relates to a work machine, in particular a duty-cycle crawler crane, having an undercarriage which comprises a middle part and at least one crawler carrier which is connected to the middle part and comprises at least one electric traction drive, wherein at least one supply line runs from the middle part to the traction drive and is connected to the latter in a disconnectable manner via a first connection. According to the disclosure, the work machine comprises an electrical interlock loop, which is connected to the traction drive via the first connection, and a mating plug connector module, which is arranged on the undercarriage and has a first mating connection for connecting to the first connection of the supply line and is configured to bridge the interlock loop, which is interrupted by a disconnection from the traction drive, in a current-conducting manner.

A method of positioning a movable structure of an overhead crane, the movable structure being either a trolley or a bridge of the overhead crane, the method comprising providing a position reference for the movable structure, controlling with a state-feedback controller the position of the movable structure, the position of the movable structure and a sway angle of the load being state variables of the system used in the state-feedback controller. Further the method comprises determining the position or speed of the movable structure and the sway angle of the load or angular velocity of the load, providing the determined position or speed of the movable structure, the determined sway angle of the load or angular velocity of the load and the output of the state-feedback controller to an observer, producing with the observer at least two estimated state variables, forming a feedback vector from the estimated state variables or from the estimated state variables together with determined state variables, using the formed feedback vector as a feedback for the state-feedback controller, and providing the output of the controller to a frequency converter.

A method is provided for controlling an operation of a mobile crane, the operation comprising a user input, the user input comprising a command to change a configuration of the mobile crane. The method comprises the steps of: determining a current tipping moment of the mobile crane, the tipping moment comprising a moment about a tipping line of the mobile crane; predicting an effect of the user input on the tipping moment of the mobile crane; and if the predicted effect of the user input is to increase the tipping moment of the mobile crane past a predetermined amount, altering a response to the user input. A system for controlling an operation of a mobile crane, and a user display system for a mobile crane are also provided.

Personnel working at elevated positions use safety lines to prevent falls. Equipment being used in proximity to the personnel may interfere with the safety lines presenting a potential hazard. A fall protection monitor provides an automated and wireless sensor system for avoiding interactions between equipment and safety lines. The fall-protection monitor includes a first sensor for monitoring whether a safety line is in operation. A second sensor monitors a location of a moveable device being used in the vicinity of the safety line. A controller determines the location of the moveable device and whether the safety line is in operation. The controller prevents movement of the moveable device within a predetermined distance from an operational safety line.

A system for managing working modes of a mobile crane in a job site, the system comprising: a position sensor for the mobile crane in the job site, a position sensor for the hook of the mobile crane relative to a reference point of said mobile crane, a module for managing the working mode of the mobile crane configured to define the working mode of the mobile crane selected from: the displacement mode corresponding to a displacement of the mobile crane in the job site, the fixed work mode corresponding to a situation in which the mobile crane is fixed in the job site and the position of its hook is variable, a communication device configured to communicate an indication of the working mode of the mobile crane to at least one other crane of the job site.

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.

Various hoisting systems with anti-two-block sensing devices are provided. In one embodiment, an apparatus includes a crane having a hoisting line and an anti-two-block sensing device installed about the hoisting line. The anti-two-block sensing device includes an upper chandelier, a lower trigger assembly suspended from the upper chandelier, and a detector positioned to detect movement of the lower trigger assembly with respect to the upper chandelier. The lower trigger assembly can include two plates each having a hoisting line aperture and a slot that allows transverse installation of the plate about the hoisting line. Further, the two plates can be positioned such that their slots are offset from one another and the plates cooperate to fully surround the hoisting line. Additional systems, devices, and methods are also disclosed.