wheel and axle
wheel and axle definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a larger wheel or pulley that is fixed to a shaft, a smaller wheel or pulley, or a drum, to increase mechanical advantage or speed: the wheels are often grooved and operated like pulleys
wheel and axle definition by American Heritage Dictionary
A simple machine consisting of an axle to which a wheel is fastened so that torque applied to the wheel winds a rope or chain onto the axle, yielding a mechanical advantage equal to the ratio of the diameter of the wheel to that of the axle.