In mechanics, a wheel that carries a flexible rope , cord, cable, chain, or belt on its rim.
Pulleys are used singly or in combination to transmit energy and motion . In mechanical advantage , especially for lifting weights. The shafts around which the pulleys turn may attach them to frames or blocks, and a combination of pulleys, blocks, and rope is called a block and tackle . The pulley is considered one of the five simple {{link=machine">machines .