MOVABLE PULLEY HEADS FOR A LATERAL SPREADER MOVEMENT

When the crane is positioned over the pile, the spreader must longitudinally coincide with the container. This can be obtained in two ways: moving the gantry or laterally moving the spreader. Movement of the gantry is not advisable in small approach maneuvers, obtaining gentler and more precise maneuvers using a spreader which allows being laterally moved in relation to the crane, preventing intermitting starts and stops which are detrimental to translation transmission. Some of the features of the described system are: Four operating points coordinated by means of hydraulic valves. A large and heavy frame, which is necessary when a single operating point is used, is eliminated. Power drive screws actuated by small and lightweight motors are used, assuring smooth and self-blocking running.