A cycloidal drive or cycloidal speed reducer is a mechanism for reducing the rate of an input shaft by a certain ratio. Cycloidal swiftness reducers are capable of fairly high ratios in small sizes. 
The input shaft drives an planetary gearbox eccentric bearing that in turn drives the cycloidal disc in an eccentric, cycloidal movement. The perimeter of this disc is geared to a stationary ring equipment and has a group of output shaft pins or rollers positioned through the face of the disc. These result shaft pins straight drive the result shaft as the cycloidal disc rotates. The radial movement of the disc is not translated to the output shaft.