Schematic animation of Watt's sun and planet gears. The Sun is yellow, the planet red, the reciprocating crank is blue, the flywheel is green and the driveshaft is grey. Notice that the sun and flywheel rotate twice for every rotation of the planet.

The sun and planet gear (also called the planet and sun gear) was a method of converting reciprocal motion to rotary motion and utilised a reciprocating steam engine. A steam engine is a Heat engine that performs Mechanical work using Steam as its Working fluid.

It was likely invented by the Scottish engineer William Murdoch, an employee of Boulton and Watt, but was patented by James Watt in October 1781. Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. William Murdoch (sometimes spelled Murdock) ( August 21, 1754 - November 15, 1839) was a Scottish engineer and inventor The firm of Boulton & Watt was initially a partnership between Matthew Boulton and James Watt. James Watt ( 19 January 1736 &ndash 25 August 1819 Boulton proved to be an excellent businessman and both men eventually made fortunes Year 1781 ( MDCCLXXXI) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common It played an important part in the development of devices for rotative motion in the Industrial Revolution. The Industrial Revolution was a period in the late 18th and early 19th centuries when major changes in agriculture manufacturing and transportation had a profound effect on the

Operation

The sun and planet gear converted the vertical motion of a beam, driven by a steam engine, into circular motion using a 'planet', a cogwheel fixed at the end of the pumping rod (connected to the beam) of the engine. This is the page for mechanical Gears For other uses see Gear (disambiguation For the gear-like device used to drive a roller chain see Sprocket This is the page for mechanical Gears For other uses see Gear (disambiguation For the gear-like device used to drive a roller chain see Sprocket With the motion of the beam, this revolved around, and turned, the 'sun', a larger rotating cog which turned the drive shaft, thus generating rotary motion. An interesting feature of this arrangement, when compared to that of a simple crank, is that when both sun and planet have the same number of teeth,the drive shaft completes two revolutions for each stroke of the beam and not a 1:1 ratio as expected. A crank is an arm at right angles to a shaft (an Axle or spindle by which motion is imparted to or received from the shaft it is also used to change circular into Reciprocating

See also

• Epicyclic gearing
• Beam engine

External links

• Sun and planet gear animation
• Henry Ford Museum Watt Rotative Engine