A notched wheel is a type of wheel with a series of notches cut into its circumference. It is often used in conjunction with a RATCHET, which is a device that allows movement in one direction only, and a GEAR or COG, which is a toothed wheel that meshes with another toothed wheel to transmit rotational force. Together, these components form a mechanism that can be used for a variety of purposes, such as winding a clock or powering a machine.