An electronic clock making use of an electromagnetically actuated tuning fork whose vibrations are converted into rotary motion for driving the gear train of the clock by means of a motion transformer including a V-shaped indexing element. The ends of the indexing element are attached to the tines of the fork at corresponding points thereon, and the vertex thereof is flattened to define a rectangular tongue whose edge engages the ratchet teeth of an index wheel whereby as the tines vibrate, the tongue reciprocates in a rectilinear path at right angles to the direction of vibration. The index wheel is joined to a worm gear coupled to the first wheel in the gear train, the worm gear being supported for rotation between a fixed pivot and a spring-biased pivot, whereby sufficient friction is introduced to prevent retrograde motion of the index wheel.
