A cycloidal drive or cycloidal swiftness reducer is a system for reducing the acceleration of an input shaft by a particular ratio. Cycloidal velocity reducers can handle fairly high ratios in small sizes. 
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The input shaft drives an eccentric bearing that in turn drives the cycloidal disc within an eccentric, cycloidal movement. The perimeter of the disc is targeted at a stationary ring equipment and has a group of output shaft pins or rollers placed through the planetary gearbox facial skin of the disc. These result shaft pins directly drive the result shaft as the cycloidal disc rotates. The radial motion of the disc isn’t translated to the output shaft.