The driving link is carrier 1 which rotates about fixed axis A and is connected by turning pairs B to planet gears 2 and 3. Gears 2 and 3 mesh with and roll around fixed sun gear 4. Levers 5 and 6, rigidly attached to the shafts of gears 2 and 3, carry rollers 7 and 8 whose centres describe epicycloids a-a and b-b. Sliding along slots c-c and d-d of disk 9, rollers 7 and 8 rotate it at a velocity that varies periodically from zero (when the centres of the rollers are at points K₁ and K₂ of their paths) to a certain maximum (when the centres of the rollers are at points L₁ and L₂ of their paths) and back again to zero. Since gears 2, 3 and 4 have the same pitch diameter, the period of velocity variation of driven disk 9 is equal to the time required for one revolution of driving link 1 about axis A.
$2465$LrG,ML$