Abstract: A quick return mechanism incorporating noncircular gears is presented. During the course of designing, the noncircular gears’ pitch curves are divided into two parts to discuss, I.e. uniform-velocity range and accelerating range. Two kinds of superior speed-ratio functions are accquired by comparing three kinds of speed-ratio functions which are attained here. The designed mechanism can make the output part get uniform velocity in the working area and better quick return character. It is more suitable for different needs than traditional six-bar quick return mechanism in practical applications.

Key words: Noncircular gears, Pitch curves, Quick return mechanism