Eta A.g. Ebauches-fabrik

Pierre-Alain Vuille

Friedrich Perrot

Eric Favre

In a timepiece movement, more particularly a quartz wrist watch movement, having a low-torque stepping motor, there is provided a differential mechanism which drives the hands and makes it possible to move the hour-hand alone in jumps. A cannon-pinion having a toothing acts as a sun gear. A planet gear is mounted on an hour-wheel which acts as a planet carrier. A ring gear takes the form of an annulus having internal teeth which is normally stationary but is controlled by a stem and can be rotated by jumps to cause the planet gear to roll along the cannon-pinion toothing, thus causing the planet carrier and consequently the hour hand to jump.

Timepiece movement with differential gear mechanism

A hairspring and collet assembly for timepieces in which the collet has a base having an opening and a stud integral from the base in a direction parallel to the axis of the opening. The hairspring comprises an inner turn ending in a bend. The stud occupies a portion of the base extending between the opening and the periphery of the base. The non-deformed portion of the inner turn of the hairspring is secured to the stud and the bend extends freely away from the stud about the opening.

Growing community of inventors

Tramelan, Switzerland

Pierre-Alain Vuille