Crane for transferring cargo from ship to shore - has computer controlled auxiliary drum to maintain cable tension despite rough sea (NO 20.11.78)

摘要

The transfer of cargo from ship to shore by a crane is difficult during a heavy swell which causes the ship to rise and fall. This is solved by fitting the crane (1) with an auxiliary winding drum (4) which receives one end of the main lifting cable (9). The other end of this cable is wound on the main drum (3). A computer measures the tension in the cable (9) and controls the auxiliary drum so that this tension equals the weight of the lifting hook and pulley block (12). As soon as this tension is exceeded the auxiliary drum is braked and the main winding drum is set in motion to lift the load (10).