Sun and planet wheels

(Mach.)

an ingenious contrivance for converting reciprocating motion, as that of the working beam of a steam engine, into rotatory motion. It consists of a toothed wheel (called the sun wheel), firmly secured to the shaft it is desired to drive, and another wheel (called the planet wheel) secured to the end of a connecting rod. By the motion of the connecting rod, the planet wheel is made to circulate round the central wheel on the shaft, communicating to this latter a velocity of revolution the double of its own.

See also: Sun