Model: S04 Oblique Double Slider Ellipse and Straight-line Mechanism
This model is related to the mechanism S-1, S-2, S-3 and in particular the double slider mechanism with perpendicular guides. Here the two guides are at an oblique angle. The model shows that one can find a point on the connecting link between the two slides which traces out a circle and therefore can serve as a cylindrical joint for a crank. The model demonstrates that both the oblique double slider and the related special slider crank, also demonstrated in model S-3, can generate an exact straight line motion.

The use of linkages to draw mathematical curves has a long history. The double slider crank or 'Trammel' mechanism for example (Model S-2), has long been used to draw exact ellipses. The invention has been attributed to Benjamin Bramer (1588-1652) c. 1600, as well as to Frans von Schooten (1615-1660), Dutch, around the same period.

Francis Moon 2003-07-01

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