...and now a question about Paul Vallette

Thanks for reading my post about the Rose watch. I also have another Heuer-related timepiece, a pre-WWII Paul Vallette split-timer. I'd be grateful for any info the members here can provide. I'll share what details I can.

I bought this 15-20 years ago when I was in a phase of collecting split-seconds timers. I had a fairly large assortment of them (Omega, Lemania, Guinand, Minerva, Hanhart, etc.) but the most striking of them, visually, is this Vallette. The dial is spectacular--blue hands, crisp printing and pristine enamel:



I'll have to check to see if I have old notes that indicate what movement this may be--perhaps it rings a bell from the Heuer stables?



I like it so much, I used a version of this image for a personal avatar at one point:



It is one of the few I have retained from this collection I had back in 2002:

Paul Vallette seem to be part of the Heuer / Rose connection in the sources I posted in the Rose thread. I have found a few more showing that the three were connected but do not think they add much to dating your watch.

Thanks. I'll review the sources you provided. Upon a quick look through Ranfft for 19-ligne chronograph and timer movement, the Vallette movement seems very similar to Minerva Cal. 9, but I doubt that's the base caliber. There are similarities also, in part, with Venus, Valjoux and Lemania components. I wonder whether anyone sees a Heuer connection other than what is known about Heuer/Freund's use of the Vallette name.

Surprisingly, it is a variant of this movement from a Semikrograph!:

More evidence that my Vallette is related to the Heuer Semikrographe:

http://www.goldschmiede-zwehn.de/mikrographen.htm

Version with split-seconds. It appears to have Swiss patent numbers 73392 and 73393:

Another update--thanks for the help here.
This Vallette was also produced as Heuer Ref. 540, as found in catalogues from the 1930s into the 1960s. Based upon the 1930s catalogue details, I assume mine is from that period or perhaps 1920s.