Four-part gearboxes are to be determined in such a way that the rotating drive member (crank) passes through a given crank angle, while the oscillating drive member describes a given oscillation angle or stroke between its reversal positions. These angles are called dead center angles. With the help of this guideline, gearboxes that fulfill this task can be determined graphically or mathematically and, above all, those that have the largest possible transmission angle or the lowest possible maximum acceleration of the drive member can be found.*www.vdi.de/2130