Toothed gear 1 rotates about axis A and meshes with pin rack 2 having pins d. Trunnion A of gear 1 slides along slot a-a of rack 2. The slot has two straight and two semicircular portions. Gear 1 is connected by turning pair A to lever 3 which turns about fixed axis B. When driving gear 1 rotates continuously in one direction at uniform velocity, driven rack 2 reciprocates at uniform velocity in fixed guides b-b. Rack 2 is reversed by the semicircular portions of slot a-a. While gear 1 is passing from its upper to its lower position and vice versa, rack 2 travels with nonuniform velocity. The profiles of teeth e of gear 1 are along curves which are equidistant to an involute of a circle. Weight D counterbalances the weight of gear 1.
$2580$PG,3L$