Assembly of simple eccentric

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An eccentric in mechanical engineering refers to a circular disk fixed on a rotating axle with its center displaced from the axle's center (hence, the term "eccentric"). These disks are commonly used in steam engines to transform rotary movements into linear reciprocating motions, such as for driving sliding valves or pump rams. Eccentrics have a groove at their circumference that fits a circular collar (eccentric strap), with an attached eccentric rod that can impart required motion via suspension of its other end. Unlike return cranks, which are limited to functioning at axle ends or wheel outsides, eccentrics can also be fitted within the axle between wheels. However, they can only provide simple harmonic motion unlike cams, which convert rotary into linear motion at various rates of acceleration and deceleration.