A clock designed to recover as much energy as possible delivered by the fall of one ball per hour.
The winding order is given whenever the minute hand is vertical: a rod lifts the ball from the bottom, pushes aside five others arranged in a circle and then pushes a small column of balls inside a glass tube. The five balls close behind it and prevent the balls in the column from falling back down. The marble at the top of the glass tube rolls through a maze of four grids and four nails every hour. It pushes the balance wheel in the direction of oscillation and finally lands at the bottom of the mechanism where it waits for the next hour.
Another sensor counts the passages of the balance and sends its impulses to the seconds hand. The frame is triangular to avoid any torsion that would cancel the inertia of the balance. The precision obtained is of the order of less than ten seconds of shift per month.
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