Industry News – Sinn Announce DIAPAL Oil-Free Escapement
Sinn have introduced a new section on their website called “Technik Lexikon” (technical dictionary) where they in a very easily understandable way explain the new developments they’re working on. It’s only available in German though. Apart from the announcement of their 1,200 Vickers TEGIMENT case and self-designed chrono-module (see German Brands Forum), the current page also describes a novelty which is, from a horological viewpoint, even more significant than the other two: a modification of the Swiss anchor escapement which requires no oil!
I’ll try to explain the modification using diagrams from Walt Odet’s Horologium and a translation of the text from the Sinn website.
Sinn Innovation On The Swiss Anchor Escapement
The Swiss anchor escapement has been a tried and proven escapement for wristwatches for over a century. Nonetheless it has a known weakness. To work properly, the pallet jewels (10) and the surfaces of the escape wheel (5) have to be oiled to reduce friction. An un-oiled escapement will usually cease to function within a few weeks.
Although the oils used in watchmaking have been incredibly improved since the beginnings of watchmaking, they’re still susceptible to changes due to humidity and abrasion of metal parts. This inevitably leads to a lower amplitude (of the balance wheel) and affects the daily rate.
For this reason most companies advise to have a mechanical watch serviced and freshly oiled every two to four years.
The quality and quantity of the oils isn’t so critical in every part of a mechanical movement. The wheel train is much less sensitive in this regard than the escapement.
So one way to overcome this weakness is to modify the escapement itself so that that the friction between two parts is kept to a minimum in the first place. This method was invented by George Daniels and successfully brought to series by Omega.
Sliding friction in a conventional lever escapement:
Radial friction in the Daniels co-axial escapement:
Here at Sinn, we took an alternative route which takes advantage of the reliability of the Swiss anchor escapement and approaches the root of the problem, the oils.
Proven Tradition Goes Hand In Hand With Modern Aerospace Technology: The DIAPAL
Research on the DIAPAL technology began in 1995 when Sinn had the idea to exchange the palette jewels(10) with Diamond Palettes. As mentioned, in a normal escapement the oil is only necessary to reduce friction between the rubies of the palette jewels and the steel of the escape wheel. We found out that a polished diamond already reduces the friction noticeably compared to the traditionally used ruby. But the results without the use of oil did not yet lead to a satisfactory amplitude. From now on, all improvements towards achieving an oil-free movement will go under the name of DIAPAL technology. In the year 2000, Sinn filed for two patents in this regard.
Instead of modifying the material used in the pallet jewels, a change of the escape wheel is just as conceivable as it’s the “friction partner” of the anchor. Here modern aerospace technology is applied. Because of the atmospheric pressure in space, oils can’t be used as they would immediately vaporize. For this reason, materials were researched which together had a low friction coefficient. With this technology it’s possible to achieve low friction without having to lubricate the parts with oil. Under ideal conditions the amount of friction is lower than between a freshly oiled pallet jewel ruby and the steel escape wheel.
The DIAPAL Technique Goes Into Series
We plan to present the first model with a completely oil-free Swiss anchor escapement this year. The newly developed escape wheel will be used together with a conventional pallet jewel ruby. This way we were able to combine the proven Swiss anchor escapement with modern aerospace technology and eliminate its weakness.
By Dr. Wolfgang Schonefeld, 2003 www.sinn.de
I am very impressed by the path Sinn are taking, to improve the basic elements of a watch. If I imagine a watch using the ultra hard TEGIMENT case, the DIAPAL escapement in conjunction with their very legible new SZ01 chrono-module, the argon gas filling, copper sulphate capsule and their 756 pusher lubrication system, I am seeing useful invention which is absolutely peerless in the industry.