Screw (simple machine) of the last of the simple machines to be invented. It first appeared in ancient Greece and Egypt, and by the first century BC was used in the form of the screw press and the Archimedes' screw, but when it was invented is unknown. Greek philosopher Archytas of Tarrentum (428 – 347 BC) was said by the Greeks to have invented the screw. Although the Greek philosopher Archimedes is credited by the Greeks with inventing the Archimedes screw water pump around 234 BC. records indicate it was first used in ancient Egypt. Archimedes was first to study the screw as
Trammel of Archimedes Trammel of Archimedes A trammel of Archimedes is a mechanism that generates the shape of an ellipse. It consists of two shuttles which are confined ("") to perpendicular channels or rails and a rod which is attached to the shuttles by pivots at fixed positions along the rod. As the shuttles move back and forth, each along its channel, the end of the rod moves in an elliptical path. The semi-axes "a" and "b" of the ellipse have lengths equal to the distances from the end of the rod to each of the two pivots. An ellipsograph is a trammel