Indexing mechanism for horological instrument

Claim 1

An indexing mechanism for timepieces comprising: a frame, an oscillatory timing wheel rotatably mounted to the frame, means to impulse the timing wheel to provide oscillatory movement thereof, an index lever rotatably mounted to the frame and oscillated by the timing wheel, an index wheel having a plurality of teeth positioned about its periphery to be engaged by the index lever and advanced in predetermined steps, magnet means positioned adjacent the index wheel teeth to hold the index wheel at the end of each step by exerting a directed torque on the index wheel teeth, the magnet means comprising a pair of spaced-apart magnets which are skewed in a predetermined manner said magnets being designed to interact with the teeth of the index wheel locking the pins of the index lever against the forward draw faces by exerting a forward torque on the teeth, at least two banking pins mounted to the frame at spaced intervals on opposite sides of the index lever to limit the movement thereof, and, the index lever includes bifurcated end portions, one of said end portions having a pair of arms and an index pin mounted to each arm to alternately engage the index wheel teeth advancing the index wheel an amount equal to one-half the tooth pitch during each engagement, and, the index wheel teeth include shaped draw faces to be engaged by the index pins.