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Double-Eccentric Ratcheted Winding System


Double-Eccentric Ratcheted Winding System
Today, a self-winding automatic is one of the standard characteristics of most mechanical watches. Nevertheless, many of the watches have a winding system which only winds on one side. This means that half of the potential distance remains unused. With the construction of the Damasko winding systems, a great level of importance is placed on ensuring that no idle speed is generated, keeping the backlash as small as possible and increasing the working life. The solution was found with the ratcheted winding system which winds on both sides due to its double-eccentric mounted ratchets.

If the rotor moves the two eccentric wheels and thus the ratchets from the lowest point in the direction of the highest point, the first ratchet moves the ratchet wheel and thus winds the mainspring. With the subsequent movement from the highest to the deepest point, the second ratchet moves the ratchet wheel and thus also winds the mainspring. Should the rotary motion not be enough to reach one of the two points, the distance covered by the respectively opposite ratchet is transformed into a winding movement.

In order to keep the backlash, or the unused distance with a rotation direction, as low as possible, a ratchet wheel was needed with an exceptionally fine tooth system. The fine tooth system ensures that the ratchet wheel continues to move, even in the case of the smallest rotary movements of the eccentric wheels. In order to keep 140 teeth at the highest level of precision to a diameter of only 5.30 mm, it was necessary to galvanically allow this to increase by using the newest technologies, the so-called LIGA procedure. Only by doing this was it possible to obtain a toothed wheel with the highest amount of precision and basic hardness. There was also the desire to set new standards in the area of the durability and the maintainability of the system. Therefore, it was decided with the mounting of all winding components, to furnish all of the wheels from the rotor to the mainspring with our newly developed, lubrication free four-point micro ball bearing. This minimises friction, distributes the occurring forces, checks for ceramic balls and their hardened track.

In so doing this, a winding system was able to be created which winds faster than a normal winding system and which can supply a stronger mainspring with power for many years without the need for repair.