Alberto, help, need info on the calibre 97975 QP

Hi Alberto --so I'm digging around and ran across the 1892 QP patent which looks like it has the twelve toothed starwheel/12 step program wheel with maltese cross for the dates of February that Patek used in its wristwatch QPs in the 40s. Here's my big question --was the patent specifically to make a smaller QP caliber by reducing the size of the usual 48 step program wheel? Seems like it's save a good bit of space but then I've seen other QPs like the Kurt Klaus design for IWC that DID use a 48 step program wheel. Help. . .?

Jack

Your deduction makes perfect sense, but let me see what I can dig up for you.

Alberto Schileo
Patek Philippe Forum Moderator
Tempus fugit, horologia manent

. . . much appreciated and I await the results of your research with much interest. Funny how many basic things there are still to learn; good thing I guess as it keeps things interesting .

Jack

will upload that in my brain and sleep over it.

MarkS

So, Jack, I have not been able to find out a whole lot, but here is what I got...

First, I did not find trace of an 1892 perpetual calendar patent. What I did find is that on May 23rd 1889, Patek was awarded patent N. 1018 for a pocket watch perpetual calendar mechanism, so I presume you are referring to this one.

This patent covered a QP mechanism which Jean Adrien Philippe, who died in 1894, had been using for some time in various iterations, which were all subsequent refinements of the previous variants.

My understanding is that the main objective of the patent, however, was not the compactness of the mechanism (those were, after all, pocket-watch days - the first wrist iteration of a QP by Patek only saw the light in 1925, and only entered regular production in the very early '40s), but rather flatness, and - primarily - the instantaneousness and simultaneousness of the jump of the various indicators.

In my opinion, using a 12-step program wheel, with the only variable step addressed by a specific sub-wheel, is a much more elegant and refined solution from a theoretical perspective than a 48-step program wheel, though the latter might be simpler to implement (and perhaps less prone to failure in the long run?). But not being a watchmaker I doubt that my opinion counts for a whole lot...

Alberto Schileo
Patek Philippe Forum Moderator
Tempus fugit, horologia manent

...if flatness alone had been a driving force behind this patent, then the 48-step program wheel would have made more sense, as it would have been thinner overall (no need for stacking two components). However, since it was also meant to be a simultaneous, instantaneous perpetual calendar, space might have been at a premium to accomodate the various levers and cams necessary to achieve this result, and this might actually explain the need for a program wheel as compact as possible.

Alberto Schileo
Patek Philippe Forum Moderator
Tempus fugit, horologia manent