גלגלות

Pulleys, also called sheaves, transmit mechanical power across greater distances than systems that use gears and are part of a drive system connected by a belt. The load requirements of an application may determine the configuration of this drive system, in which flat belt, v-belt, and timing belt pulleys are respectively capable of handling progressively greater driven loads. A sheaf is generally made of steel or cast iron but may also be made of aluminum, polycarbonate resin, thermoplastic, or nylon where load requirements permit them and their lighter weight provides an advantage. An industrial or heavy duty pulley generally has a keyway that aligns with the keyway on a splined shaft, which locks the pulley in place and provides a greater torque-handling capability. Where torque requirements are high, pulley systems may have multiple pulley wheels and use multiple belts. When choosing a pulley, consider the environment in which it is used and the load requirements of the driven sheaf.