Links 1 and 2 are connected by turning pairs A and B to the base, and their turning axes are perpendicular but do not intersect. Links 1 and 2 contact each other through round cylinders a and helical surface d cut into cylinder b. The axes of cylinders a are perpendicular to and intersect the turning axis of link 2. The axis of cylinder b, on which helical surface d is cut, coincides with the turning axis of link 1.
$509$SL,CL$