Ballistics Drive

A differential mechanical device which receives angular motion from a parallelogram linkage attached to a gun trunnion. It receives superelevation data from a computer, ballistics and transmits the angular value received from the gun, plus superelevation data to a gunner's periscope, thereby compensating for the ballistics of the projectile. It also provides synchronization to the range finder, fire control. It may include a temperature compensating linkage.