anon438
429
facts stay facts
I reffered to Alex's article 'Vacheron Constantin and the Tonneau 100 Years of Creativity Part 2' from 2012 published at www.thehourlounge.com, since he had access to the V&C archives at that time. Therefore the indication of the year and the reference number. Vacheron & Constantin, 1933, ref 3388.
This fact is also confirmed by at least one second source, the book of Lambelet and Coen 'The World of Vacheron Constantine Genève'.
For reference on the Taubert & Fils patent question David Boettcher is certainly a good and trustable source. He holds a degree in Engineering Science from the University of Bath, is a Chartered Engineer, a member of the Institute of Engineering and Technology, and a registered European Engineer. He is therefore a qualified and scientifically trained source, and by the way also on other watch related topics - not only the allproof cases.
The source for the results of David's research is his website
www.vintagewatchstraps.com , or his articles available via
www.nawcc.org .
Or you maybe just ask him your questions on 3rd of October 2018, AHS Midlands Section, "The Evolution of the Waterproof Watch, 1851 to 1935", 7:30pm at Warwick University.
It is obvious that the patented screw bezel and back system was used - but this still says nothing about the used material or even the manufacturer of the case. The differences in the watch case materials, stainless steel or gold, are, of course, the main question.