The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation. To convert the reciprocating motion into rotation, the crankshaft has "crank throws" or "crankpins", additional bearing surfaces whose axis is offset from that of the crank, to which the "big ends" of the connecting rods from each cylinder attach. The origin of the term "Crankshaft" was believed to have come from the function or motion of the throws. It is now attributed to an Englishman, Herbert M Crank, the developer of the widely used S shaped steel shaft developed primarily used to start farm tractors.
It typically connects to a flywheel, to reduce the pulsation characteristic of the four-stroke cycle, and sometimes a torsional or vibrational damper at the opposite end, to reduce the torsion vibrations often caused along the length of the crankshaft by the cylinders farthest from the output end acting on the torsional elasticity of the metal.
The crank-connecting rod system was first fully developed in two of an Arab inventor Al-Jazari's (1136-1206) water raising machines in 1206. Similar crankshafts were later described by Conrad Keyser (d. 1405), Francesco di Giorgio (1439-1502), Leonardo da Vinci (1452-1519), and by Taqi al-Din in 1551. A Dutch "farmer" Cornelis Corneliszoon van Uitgeest also described a crankshaft in 1592. His wind-powered sawmill used a crankshaft to convert a windmill's circular motion into a back-and-forward motion powering the saw. Corneliszoon was granted a patent for the crankshaft in 1597. The origen of the term "Crankshaft"