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. 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 instead of one.
US Patent Issued to SL on Dec. 7 for "Cable-Driving Apparatus and Parking Brake System Using Planet Gear Assembly" (South Korean Inventors)
Dec 14, 2010; ALEXANDRIA, Va., Dec. 14 -- United States Patent no. 7,845,472, issued on Dec. 7, was assigned to SL Corp. (Daegu, South Korea)....