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The double axis tourbillon was 1st patented by the brilliant English watchmaker, Anthony G. Randall in 1978 and 1st made by another Englishman, the gifted watchmaker, Richard Good, also in 1978. The double axis tourbillons made by Randall, Good and, much later by, Richard Habring were in the form of carriage clocks.
A vision heís had since his time as an apprentice, Master Watchmaker Thomas Prescher has wanted to make a double axis tourbillon. More than 10 years later, after being inspired by the work of the Masters above, he has realized it in brilliant fashion.
The torkel tourbillon (the term coined by Reinhard Meis in his classic book Das Tourbillon to describe the tumbling action of the tourbillon, as it rotates through two axis) made by Mr. Prescher reduces the size of the tourbillon considerably. So much so, that his version may be fitted in a pocket watch! No small feat of engineering.
A tourbillon is designed to average out the vertical errors of poise caused by gravity on the balance and balance spring. This it does quite well, but it does not address the change of rate between horizontal and vertical positions, which, in large part, is caused by the change of friction on the balance pivots, which adversely affects the timekeeping. The theoretical solution to this is the torkel tourbillon. This is accomplished by rotating the tourbillonís carriage in two planes, that is, at right angles to each other.
Besides the engineering challenges of creating a tourbillon, which rotates through two axis once per minute, it was soon realized that a constant force escapement would be necessary to obtain a state of poise between the two axis. A constant force escapement is a type of remontoire that employs a subsidiary spring on the escape wheel and provides the motive force to the balance. Not only was this a solution for equilibrium, but it also addressed isochronal errors.
With the arduous research and design tasks completed, Mr. Prescher begins the fabrication process in 2002. Using a Unitas pocket watch as his working base the following components were made to bring his dream to life:
Carriage was electro-eroded by specialist. Remaining carriage components made by Prescher. All constant force components made by Prescher. 1st and 2nd wheels of second axis modified from existing stock. Crown wheel made for second axis by Prescher. Case: Working example in brass, but final product will be encased in gold. Made by Prescher Size: 60 mm in diameter & 20-22 mm in height. Dial: Mother of Pearl with two chapter rings for hour and minutes and the other for seconds. Opening at 12 to view double axis tourbillon. Made by Prescher.
Now, with a working example (it is a marvel to behold), the plans are two fold. 1. To design and make a twin barreled movement for his Torkel pocket watch and, 2. Reduce the size of the Torkel to that of a wristwatch. 2003 will be a busy year indeed!
Please stay tuned, as we will be revisiting the Torkel Tourbillon in a detailed article and investigating other horological delights from the workshop of Thomas Prescher.
For more information on the Torkel Tourbillon, and to see it in action, you may visit Mr. Prescher at Basel 2003 where heíll be exhibiting with the AHCI.