A cargo crane including an arm turning mechanism that turns a crane arm; an arm luffing mechanism that adjusts the luffing angle; an arm extension and contraction mechanism that adjusts the arm length; and a control device that calculates a trajectory in which a suspended cargo is conveyed, and that controls the mechanisms. The control device calculates the trajectory so as to be a straight line trajectory as viewed from at least the vertical direction; calculates a turning angle θ, a luffing angle φ, and an arm length L so as to cause the trajectory to be the straight line trajectory by using the cargo start position, the cargo target position, a maximum speed v.sub.max, a suspended cargo swing cycle T, and a start-up time T.sub.1; and controls the mechanisms so as to achieve the calculated turning angle θ, luffing angle φ, and arm length L.

When performing the conveyance from an arbitrary cargo start position to an arbitrary cargo target position, it is possible to control swing prevention without constraint condition and with a simple control system. There is provided a cargo crane including an arm turning mechanism (4) that turns a crane arm (2); an arm luffing mechanism (3) that adjusts the luffing angle; an arm extension and contraction mechanism (5) that adjusts the arm length; and a control device that calculates a trajectory in which a suspended cargo (7) is conveyed, and that controls the arm turning mechanism (4), the arm luffing mechanism (3), and the arm extension and contraction mechanism (5). The control device calculates the trajectory so as to be a straight line trajectory as viewed from at least the vertical direction, according to the cargo start position and the cargo target position; calculates a turning angle θ, a luffing angle φ, and an arm length L so as to cause the trajectory to be the straight line trajectory by using the cargo start position, the cargo target position, a maximum speed v.sub.max, a suspended cargo swing cycle T, and a start-up time T.sub.1; and controls the arm turning mechanism (4), the arm luffing mechanism (3), and the arm extension and contraction mechanism (5) so as to achieve the calculated turning angle θ, luffing angle φ, and arm length L.

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 crane for lifting and transporting loads includes a base frame to transfer loads onto a support surface by a plurality of contacts in contact with the surface. An arm for lifting loads is rotatable relative to the base frame around a vertical axis. The angular range of the arm around the vertical axis includes angular fields, and load sensors. Each load sensor is associated with a respective contact to detect the force on the support surface. A control system obtains, from the load sensors, the value of the force, and detects the angular field where the arm is located. The control system determines a danger condition based on the values detected by the load sensors, according to different criteria in at least two different angular fields. The control system carries out predetermined functions of the crane, if the danger condition is reached.

A crane for lifting and transporting loads includes a base frame to transfer loads onto a support surface by a plurality of contacts in contact with the surface. An arm for lifting loads is rotatable relative to the base frame around a vertical axis. The angular range of the arm around the vertical axis includes angular fields, and load sensors. Each load sensor is associated with a respective contact to detect the force on the support surface. A control system obtains, from the load sensors, the value of the force, and detects the angular field where the arm is located. The control system determines a danger condition based on the values detected by the load sensors, according to different criteria in at least two different angular fields. The control system carries out predetermined functions of the crane, if the danger condition is reached.

A device includes a bevel pinion meshed to a bevel ring in rigid fixation with a pinion gear engaged with a slew ring to control rotation of the slew ring. A rotation sensor provides an electrical output corresponding to a rotational position of an input gear of the rotation sensor. A reduction gearing system interposes the bevel ring and the input gear of the rotation sensor. The gearing reduction system provides a reduction ratio enabling the rotation sensor to determine rotational position of the slew ring.

A device includes a bevel pinion meshed to a bevel ring in rigid fixation with a pinion gear engaged with a slew ring to control rotation of the slew ring. A rotation sensor provides an electrical output corresponding to a rotational position of an input gear of the rotation sensor. A reduction gearing system interposes the bevel ring and the input gear of the rotation sensor. The gearing reduction system provides a reduction ratio enabling the rotation sensor to determine rotational position of the slew ring.

A system control device (36): acquires the three-dimensional information of the work site, the weight of a load W, and the operating condition of the crane (1) via an input device (34) or a system-side communication device (33); upon acquiring the arrangement position and arrangement direction of the vehicle (2) at the work site via the input device (34), calculates the movable range of the crane (1) in the arrangement position and arrangement direction of the vehicle (2) taking the three-dimensional information of the work site into consideration; and overlays the image (M1) of the crane (1) and the movable range (A) on the two-dimensional image or the three-dimensional image of the work site displayed on a display device (35).

A system control device (36): acquires the three-dimensional information of the work site, the weight of a load W, and the operating condition of the crane (1) via an input device (34) or a system-side communication device (33); upon acquiring the arrangement position and arrangement direction of the vehicle (2) at the work site via the input device (34), calculates the movable range of the crane (1) in the arrangement position and arrangement direction of the vehicle (2) taking the three-dimensional information of the work site into consideration; and overlays the image (M1) of the crane (1) and the movable range (A) on the two-dimensional image or the three-dimensional image of the work site displayed on a display device (35).

When a slewing motor is at a stop, a first slewing control unit of a controller that controls an operation of the slewing motor sets a first monitoring area that is set with respect to a slewing body as a designated area, and then controls, depending on whether an obstacle is detected in the first monitoring area, whether to prohibit or allow start of the slewing motor in response to a drive manipulation. Furthermore, a second slewing control unit of the controller sets one or more second monitoring areas that are set at places remoter from the slewing body than the first monitoring area as the designated area, and then controls, depending on whether the obstacle is detected in the second monitoring area(s), whether to limit the operation of the slewing motor in response to the drive manipulation after the start of the slewing motor is allowed.

When a slewing motor is at a stop, a first slewing control unit of a controller that controls an operation of the slewing motor sets a first monitoring area that is set with respect to a slewing body as a designated area, and then controls, depending on whether an obstacle is detected in the first monitoring area, whether to prohibit or allow start of the slewing motor in response to a drive manipulation. Furthermore, a second slewing control unit of the controller sets one or more second monitoring areas that are set at places remoter from the slewing body than the first monitoring area as the designated area, and then controls, depending on whether the obstacle is detected in the second monitoring area(s), whether to limit the operation of the slewing motor in response to the drive manipulation after the start of the slewing motor is allowed.