Model: E02 Eccentric Slider Crank Mechanism
The slider-crank is a basic mechanism to convert circular motion into oscillating linear motion. The eccentric-slider is a topological cousin to the slider-crank in that it has four links, one sliding joint and three cylindrical joints. In the E series of models, Reuleaux created seven variations of this kinematic circuit by changing the ratio of the diameter of the cylindrical joints to the lengths of the links. Reuleaux called this variation “pin expansion.” In model E-2, the cylindrical joint joining the crank and the connecting link is expanded to a length greater than the crank dimension. Thus the crank pin is contained within the connecting link-crank pin. The iron circular disc seen in the model rotates about the fixed eccentric cylindrical joint. This eccentric rotation forces the connecting link to rotate and move the slider link left and right in the two prismatic joints at both ends. Eccentric-slider mechanisms were routinely used as linkages for control valves in steam engines in the 19th century. The famous American engineer George H. Corliss (1817-1888) used the eccentric in his designs for large steam engines. One of his largest steam engines was featured at the Centennial Exposition of 1876 in Philadelphia at which Franz Reuleaux was the German Ambassador.
Francis Moon 2004-07-00
- Reuleaux, Kennedy : Kinematics of Machinery (§71, Fig. 232, 233, 235, 1876)