The lengths of the links comply with the conditions: A͞B=D͞C=D͞E=A͞F and A͞D=F͞E=B͞C. Two-arm collar 1 encircles a round fixed eccentric with its centre at point A. Point G of member a, secured rigidly to link 3, has translational motion, describing a circle on flange 2. Parallel-crank linkage AFED, arranged at 90° to parallel-crank linkage ABCD, eliminates uncertainty of motion of the mechanism at its extreme positions (dead points).
$638$LW,PC$