Crank 1 rotates about fixed axis A and is connected by turning pair B to connecting rod 2 which, in turn, is connected by turning pair C to lever 3. The cam surface of lever 3 is a circular arc of radius r. Lever 3 rolls along fixed link 4 whose cam surface is a circular arc of radius R=2r. Lever 3 is connected by turning pair D to link 5 which slides in fixed guides p-p. Spring 6 holds lever 3 in contact with the cam surface of link 4. The cam surfaces of lever 3 and link 4 are designed so that point D, lying on the circle of radius r, always moves in a straight line along axis q-q which passes through the centre of the circle. Thus the rolling of a circle of radius r along a circle of radius R is the so-called motion of the Cardan circles. Reciprocating motion is transmitted to link 5 by the rolling motion of lever 3 along the cam surface of fixed link 4.
$1714$LC,RL$