Reciprocating motion - Wikipedia Reciprocating motion This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( December 2009 ) Double - acting stationary steam engine demonstrating conversion of reciprocating motion to rotary motion. The piston is on the left, the crank is mounted on the flywheel axle on the right Machine demonstrating conversion of rotary motion to reciprocating motion using gears. The bottom pair of gears drives the mechanism Reciprocating motion, also called reciprocation, is a repetitive up - and - down or back - and - forth linear motion. It is found in a wide range of mechanisms, including reciprocating engines and pumps. The two opposite motions that comprise a single reciprocation cycle are called strokes. A crank can be used to convert circular motion into reciprocating motion, or conversely turn reciprocating motion into circular motion. For example, inside an internal combustion engine ( a type of reciprocating engine ), the expansion of burning fuel in the cylinders periodically pushes the piston down, which, through the connecting rod, turns the crankshaft. The continuing rotation of the crankshaft drives the piston back up, ready for the next cycle. The piston moves in a reciprocating motion, which is converted into circular motion of the crankshaft, which ultimately propels the vehicle or does other useful work. Reciprocating motion is close to, but different from, sinusoidal simple harmonic motion. The point on the crankshaft which connects to the connecting rod, rotates smoothly at a constant velocity in a circle. Thus, the horizontal displacement, of that point, is indeed exactly sinusoidal by definition. However, during the cycle, the angle of the connecting rod changes continuously. So, the horizontal displacement of the `` far '' end of the connecting rod ( i.e., connected to the piston ) differs from sinusoidal. See also Oscillation Stroboscope Reciprocating saw Reciprocating engine Rotary reciprocating saw Agitation Scotch yoke Crank Crankshaft Swashplate Trip hammer Slider and crank mechanism Straight line mechanism Reciprocating compressor Sun and planet gear This engineering - related article is a stub. You can help Wikipedia by expanding it. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Reciprocating_motion&oldid=842184203 '' Categories : Engineering stubs Mechanical engineering Hidden categories : Articles lacking sources from December 2009 All articles lacking sources All articles with unsourced statements Articles with unsourced statements from September 2010 All stub articles Talk About Wikipedia Català Español فارسی हिन्दी Polski Română Edit links This page was last edited on 20 May 2018, at 20 : 17 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: converts linear motion of the pistons into rotary motion
Answer: crank