A lift’s operating machine – the motor on the right connects to a spring-loaded brake that fails shut so the lift can only be moved if that is released and then the gearbox (hidden behind the sheave). The gearbox is then connected to the yellow pulley, known as a sheave. This drum has the metal lift ropes around it, and they grip the sheave by gravity so there is good traction between the sheave and the ropes. 24 Sep 2011.