Abstract: An overtravel stop for a rotating shaft has a pair of gears associated with the shaft to rotate therewith. Each gear engages an associated limiting gear and the two engaged gear pairs have different gear ratios. One of the limiting gears is threaded over a shaft which is secured for rotation with the other limiting gear, such that the different gear ratios causes the one limiting gear to translate over the shaft. At selected travel limits, the one limiting gear is caused to lock relative to the other, thereby causing one of the gears associated with the shaft to shift therearound. A cam structure is provided which axially shifts a stop member associated with the shaft into engagement with a fixed stop when the one gear shifts about the shaft. Two different cam structures are shown including a pin and slot connection between the stop member and the shaft, and an ear and cam recess connection between the stop member and one of the shaft gears.