DIFFERENTIAL LIMITER DEVICE

摘要

This invention consists of a semi-automatic controlled device designed to be used on traditional cranes and bridge cranes that are equipped with twin mechanisms and clamshell. Alternately, it can be used on cranes with main or auxiliary lifting block for which it is not allowed to lift the main hook block above the auxiliary block when monitoring synchronisation.The device comprises two planetary reductors mounted in a housing; the two disks fixed at the reductors' ends rotate synchronically when the load block is moved up and down; when the clamshell is closed and opened again, the disk engaged from the lifting drum stays still, while the disk engaged from the closing/opening drum rotates by an angle corresponding to the closing travel of the clamshell. The electrical signal generated by this relative movement is picked by sensors sliding inside the sensor-holder arm mounted on the housing circumference.