The lengths of the links comply with the conditions: A͞E=B͞F , A͞D=B͞C, D͞E=C͞F and A͞B=D͞C=E͞F. The cranks of the parallel-crank linkage are designed in the form of two eccentrics 1 and 2, equal in diameter and rotating about fixed axes A and B. Connecting rod 4 has two collars a encircling the eccentrics. Link 3 prevents uncertainty of motion at the extreme positions (dead points).
$624$LW,PC$