Patent ID: 7684285
Filing Date: 2010-03-23
Classification: G04B

Abstract:
1. A power reserve indicator mechanism for a timepiece of the type comprised of a frame, an energy source formed of a barrel and a mainspring housed in the barrel, a going train driven by said barrel, and means for winding said mainspring, said power reserve indicator mechanism comprising: a power reserve indicator with an indicator wheel set and a display device carried by the indicator wheel set; a differential gear kinematically coupled by a first input to the barrel, by a second input to the winding means, and by an output to said power reserve indicator; and an intermediate wheel set including first and second parts respectively kinematically coupled to said output and to the indicator wheel set, and a coupling member coupling said first and second parts, arranged such that said power reserve indicator occupies a position comprised between first and a second end positions, the first end position reached when a winding of the mainspring is greater than an upper threshold value, and the second end position when the winding of the mainspring is less than a lower threshold value, said first and second parts rotating conjointly while the winding of the mainspring is comprised between the threshold values, wherein said coupling member includes i) a friction mechanism arranged such that the first part is movable with friction in relation to the second part when the power reserve indicator has reached the first end position, and ii) an elastic element configured to be cockable when the power reserve indicator has reached the second end position by a movement of the first part with reference to the second part, wherein said friction mechanism includes a stop secured to one of the first part and the second part, and said friction mechanism also includes a lever friction mounted on an other of the first part and the second part, and wherein said stop and said lever are disposed and sized such that i) when the power reserve indicator occupies the first end position and the mainspring continues to be wound, said lever is held against said stop and rotates with friction on the other of the first part and the second part to which said lever is secured such that the power reserve indicator remains immobile, and ii) as soon as the mainspring is let down, the power reserve indicator leaves the first end position with the first and second parts of the intermediate wheel set rotating together.