Moving counterweight for large crane - achieves equilibrium by rolling heavy cylinder on rails on rear boom to position calculated by computer for perfect balance

摘要

The counterweight adjusts the crane equilibrium automatically by moving to and fro at the rear extension of the boom. The counterweight position may be determined by automatically calculating the load weight and its position on the front boom (d). This calculation may be instantaneous, by use of a computer. The counterweight may be a heavy cylinder, rolling on rails on boom rear, (B-C), controlled by cable and remote controlled motor. Equilibrium is perfect when moments balance either side of the centre support (f). USE/ADVANTAGE - Crane booms of tens of metres long. This device has better equilibrium, wind resistance and less wear, than fixed balance weights.