Classic Escapement - Swiss Lever

Last crawled date: 1 year, 10 months ago

Based on the book CLOCK AND WATCH ESCAPEMENT MECHANICS by Mark V. Headrick (Copyright 1997) as a fine source, I try to present rigorously the essence of escapement design. The book is public (http://www.nawcc-index.net/Articles/Headrick-EscMechanics.pdf), so you can read and compare (with the book) everything I present here. My intention was to create a series of projects dedicated to this subject - as you will see - but only concerning the geometrical aspects. Actually, you can use my projects as accurate simulations for understanding the book. I recommend you to download the book in order to use it when your computer is offline. As you can learn from the book, there are three classical kinds of escapement mechanisms: Graham (dead-beat), Recoil and the Swiss Lever. Here is presented the last one.

There are two different words in English as names for the mechanical device used for counting the time: clock and watch. In Romanian, for instance, there is only one word for both: the Romanian word is „ceas” (read as „charts” without „rt”). A watch is not a clock, like a pendulum clock hanged on the wall; a wrist watch is a good example from the family of watches. The Swiss Lever is used as an escapement for watches.

The construction of the Swiss Lever Escapement is presented in the book from the page 44. It commences with the Wheel, then the Swiss Lever. If you follow the book till the end you will obtain what I already modeled. All parts, assemblies and simulation/animation are made with Inventor 2014. The main parts are the Wheel, the swiss Lever which incorporate the so called „Stones” presented in red. Next is the Balance Wheel Disc incorporating the red Impulse Pin. All of them are placed on a Plate. There you can find also the Banking Pins which limit the movement of the Swiss Lever.

Watching the Video, you can see the start of movement: note that the Wheel is the engine which make the Swiss Lever to move. Then, you will see how the Swiss Lever collides the Impulse Pin and feeds the Balance Wheel with energy at every single oscillation. The role of the Balance Wheel is obvious: to conserve energy for coming back and making the Swiss Lever to allow the rotation of the Wheel with another one step.

Because the classic spiral spring attached to the Balanced Wheel can not be simulated with Dynamic Simulation in Inventor, I simulated the spiral spring action by using a helicoidal spring and a subtle construction. You can see it on the back of Plate or in the movie here: https://youtu.be/1_o7qbnzcAA

If you want to see more, look here:
Infinite Kinetic simulation: http://uhrentechnik.vyskocil.de/fileadmin/ani/anker%28ch%29_0701.swf
Model under glass: https://youtu.be/heAS0L1jANs
Watch kinematic chain: https://youtu.be/dao0mbAbNLE
Ultimate Swiss creation: https://youtu.be/MQJFRt-2hDk

Enjoy!