Pin rack 1 with pins a slides along fixed guides b-b. Wheel 2 rotates about fixed axis A and has one spiral tooth d located on disk c. Axis A is inclined at a small angle to a normal to the plane of rack 1. When spiral wheel 2 rotates at uniform velocity, rack 1 travels with nonuniform velocity with a displacement of one pin to each revolution of wheel 2.
$2585$PG,3L$