Illustration of a machine to raise water, 16th century. A lever is a machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum. It is one of the six simple machines identified by Renaissance scientists. Man on swiveling square platform. As he turns the crank by walking around in a circle on the platform the screw on the post raises the hollow tube with the curved rods attached. These curved rods slide along the "see-saw" rods at the top. This sliding action causes the see-saw to raise on one end and lower on the other. The platform can be turned to allow the barrel to be moved to a new location and then lowered.