Model: UK006 Eccentric Slider-crank Mechanism (right)
The classic slider-crank is a mechanism that converts 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. There exist several variations of this kinematic circuit by changing the ratio of the diameter of the cylindrical joints to the lengths of the links. This variation is called “pin expansion.” In the usual slider crank, the diameter of the cylindrical joint for the crank is smaller than the length of the crank. However, in the present model, the outer bearing of the cylindrical joint fixed to the fixed link is made larger than the length of what would be the crank. Thus the connecting link-crank is contained within the crank pin. The rotary motion is affected through the motion of the black iron disc in the fixed brass bearing. The distance of the connecting link joint from the center of the rotating plate is the effective length of the crank. Eccentrics were used extensively in steam engine control linkage.

The model is obviously not made at the workshop of the Polytechnic School at Karlsruhe and seems to be the Reuleaux-Voigt model E01 made in Berlin c. 1885.

Francis Moon 2005-00-00

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