Sheave/Pulley

A sheave (also called a pulley) is a mechanical component featuring a grooved rim designed to accommodate wire ropes, cables, or belts. In hook block assemblies, it functions as a critical element in the reeving system, providing a smooth surface for rope guidance, reducing friction, and distributing load forces. Sheaves are precision-engineered to maintain rope alignment, prevent wear, and ensure safe, efficient operation in lifting applications. They are mounted on axles or bearings within the hook block frame to facilitate controlled vertical and horizontal movement of loads.

The sheave operates on the principle of mechanical advantage through rope redirection. As the wire rope passes over the grooved wheel, friction between the rope and sheave surface allows force transmission while minimizing energy loss. The groove geometry ensures proper rope seating, preventing slippage and lateral displacement. In a hook block system, multiple sheaves create a compound reeving arrangement that multiplies lifting capacity while reducing the force required from the hoist mechanism, following basic pulley system physics.