The axes of all the kinematic turning pairs should intersect at the common point 0. When crank 1 is rotated 360° about axis OA, rocker arm 3 is turned through a certain angle α about axis OD. The magnitude of angle α is determined by the relations between the constant angles ∠ AOB, ∠ BOC, ∠ COD and ∠ AOD.
$553$LW,4L$