Gear 1 rotates about fixed axis A and meshes with gear 3 which rotates about axis B of slide 2. Through intermediate gears 7 and 8, gear 1 drives gear 4 which rotates about fixed axis C. Eccentrics 5 and 6 are rigidly attached to gears 3 and 4 and rotate with these gears when they are driven from gear 1. Due to the difference in the numbers of teeth of gears 3 and 4, the relative positions of the two eccentrics gradually change, thereby varying the stroke of slide 2 which is reciprocated by link 9. The stroke of slide 2 gradually increases from zero to the maximum value and then gradually decreases to zero again. The change in the centre-to-centre distance between gears 3 and 4 does not interfere with tooth action because involute gearing is used.
$2444$LrG,ML$