Patent attributes
A load hoisting system for raising and lowering a load. A first line supports a rigid beam with unequal mechanical advantages on either side of the load. A second line supports the same rigid beam with mechanical advantages on either side of the load that are, in total, equal to those on the first line but with a ratio of mechanical advantages unequal to the ratio of mechanical advantages of the first line. One end of each line is fastened to a fixed support and the other ends of the two lines are drawn at the same rate by a power source, which system eliminates all axial rotation of the beam. The system may be applied to both ends of a long load by drawing of all lines in synchronism, advantageously being applied to lift both ends of a boat.
