Ebauches Tavannes Sa

Charles Guyot

Jacques Muller

A calendar watch movement with a double cam arrangement that drives the date-indicating wheel one step every 24 hours and locks the wheel between driving periods. The first cam has a hook that engages the toothed inner portion of the date-indicating wheel and advances the wheel by one tooth each 24 hours. The cam also has an arcuate peripheral portion that fits in between two successive teeth and locks the wheel when it is not being advanced. The first cam is integral with a co-axial star wheel which is driven by a second cam having both a hook and an adjacent shoulder that advance the star extensions. The second cam is driven by the hour wheel.

Calendar watch movement with date-indicating member

An instantaneous or step by step display mechanism for a time-keeper, including a constantly rotating driving wheel, a toothed wheel fixed to a first indication disc, a ratchet wheel also fixed to the indication disc, and a lever pivoted at one end, and carrying a dog engaging with the ratchet wheel, and an intermediate toothed wheel, at the other end. The intermediate wheel meshes with both the driving and indication disc wheels and when in use constantly runs up the indication disc wheel, carrying its end of the lever with it until the dog frees one tooth of the ratchet wheel, whereupon the lever falls back, advancing the display by one figure. The stem of the watch, when pulled, disengages the dog from the ratchet wheel and allows correction of the display, forwards or backwards. Minute, hour or date wheels may be provided.

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Tavannes, Switzerland

Charles Guyot