Hiab Ab

Cargotec Patenter Ab

Sten Sirén

Per Gustafsson

Lars Rydahl

A hydraulic crane comprising: &#x2014;a rotatable column (); &#x2014;a crane boom system () comprising two or more liftable and lowerable crane booms (); and &#x2014;an electronic control device (), which is configured to prevent an execution of crane boom movements that would make the lifting moment of the crane exceed the maximum allowed lifting moment of the crane, and to continuously establish position information as to the prevailing position of the load suspension point (P) of the crane boom system. When the lifting moment of the crane has reached a limit value at a given level below the maximum allowed lifting moment, the electronic control device is configured to prevent the execution of any combination of crane boom movements that would increase the horizontal distance between the load suspension point and said vertical axis of rotation and at the same time allow the execution of any combination of crane boom movements that keeps said horizontal distance unchanged or reduces said horizontal distance.

Hydraulic crane

A hydraulic crane comprising: &#x2014;a rotatable column (); &#x2014;a crane boom system comprising a first crane boom () connected to the column; and &#x2014;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.

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Pargas, Finland

Sten Sirén