assembly for loading and unloading products , comprising a balanced loading and unloading arm installed at a first location and having a compass - style duct system mounted by one of its ends on a base and provided at the other of its ends with a connection system suitable for connecting the compass - style duct system to a coupling means installed at the second location , this assembly comprising , in addition , a cable joined on the one hand to means integral with the base and suitable for subjecting this cable to a constant tension and suitable for being joined , on the other hand , to the second location , the assembly also comprising guiding means capable of co - operating with the cable so as to guide the connection system along a trajectory materialized by the said cable until the connection system is brought into a position of connection to the coupling means .