Collapsible portal crane for ship - has pulleys and anchor points on folding columns accommodating hoist ropes for erection

摘要

The collapsible portal crane is mounted on a ship and allows easy passage under bridges etc. Motor-driven rope hoists are mounted on the gantry, which is supported on a pair of columns, each of which has a base bolster with a lower section hinging on it. An upper section hinges on the gantry (10) and on the lower section, in the latter case by means of a knee-joint (26). Each column has pulleys (31, 32) and anchor points for the hoist ropes (16), which can be reeved so as to lift and lower the gantry. The anchor points can be on the base bolsters, and the pulleys can be coaxial to the knee joints and mounted near the column hinges on the gantry. The hoists can be vertical rams, also travelling along the gantry to positions above the columns for the erecting and folding operations.