Movement No. 114 converts uniform circular motion into reciprocating rectilinear motion using a mutilated pinion and a double rack. The pinion has teeth on only part of its circumference — the remaining portion is smooth and toothless. As the pinion rotates continuously, its toothed section first engages the top rack and drives it in one direction. When the toothed section passes and the smooth portion faces the top rack, it disengages, and the toothed section simultaneously engages the bottom rack, driving the connected slide in the opposite direction. By alternating between the top and bottom racks with each revolution, the mutilated pinion produces a back-and-forth reciprocating motion of the rack assembly. This elegant mechanism achieves direction reversal automatically through the geometry of the pinion itself, without requiring additional linkages or cams, and is well suited for applications requiring periodic reversal of a sliding element.
114. Uniform circular motion into reciprocating rectilinear motion, by means of mutilated pinion, which drives alternately the top and bottom rack.