Angle of the pink twin arm is A = 80 deg..

Angle between sliding directions of the runways is B = A = 80 deg.. The crank pivot center must be on the bisector of sliding directions of two sliders.

For the pink crank, the distance between planes, that contact with the violet rollers, and the crank’s pivot centerline must be equal to roller’s radius.

Transmission ratio of linear displacement between the blue slider and the yellow one is 1. When the yellow bar move regularly, so does the blue.

Red arrow represents resisting force.