A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulleysupported by a frame or shell which does not transfer power to a A pulley is a simple machine that is used to lift heavy objects when they require. a large force. It is sometimes called a block and tackle. Pulleys are usually used in sets designed to make the amount of force needed to lift something smaller.shaft, but is used to guide the cable or exert a force,A pulley is a device consisting of a wheel over which a rope or chain is pulled in order to lift heavy objects. The weights are moved via a cable and pulley system.