Scotch Yoke

By Spencer Connor

Often considered the original pure sine function generator, the scotch yoke is most directly derived from a sine function. It does, however, have a few considerations for implementing. The first is that there is a zero clearance between the pin and the slot, in practice this should be make as small as possible as it will produce a dead-band at top dead center and bottom dead center with no load on the sliding shaft. This is not an issue if the sliding shaft is always loaded in one direction, in fact it becomes irrelevant as the slot can be made into a simpler pusher plate. Additionally, the yoke needs to be well supported to resist lateral forces and twisting. It can be made to ride on the surface of the input disk to resist the later and a second sliding shaft can also be added below, but these are only example solutions.