WATCH TALK FORUMS banner
1 - 3 of 3 Posts

·
Banned
Joined
·
149 Posts
Discussion Starter · #1 ·
Hi all--
I noticed that Adam (GLADIATOR) posted this in another watch forum, and I thought you might be interested in reading it. I've seen the watch, and it's really beautiful. Enjoy!

Best,
Ike

"As some of you know, I collect mainly vintage watches prior to 1950, however within my collection I fell in love and also collected (modern) Dubey and Schaldenbrand watches.

Dubey and Schaldenbrand was founded in 1946 as G.Dubey.
Georges Dubey, was professor of complicated horology at the Technicum in La Chax de Fonds. In 1946 he had been joined by Rene Schaldenbrand who had been head of production of complicated watches and had designed/developed an economical fly-back seconds watch.
So both men were, outstanding Horologists.
They decided to start limited production of a split-seconds fly-back chronograph (Rattrapante) at an economical price.
They chose the name 'Index-Mobile'
In 1946, they were granted Swiss patent No. 253051, and in 1951 they received US patent No. 2548101.
To quote from the USA patent (I can not read French).
"This invention relates to..... chronographs with two co-axial long seconds hands, one of which has a 'fly back function'"


Split-Second Chronographs of the 1940s and 1950s

Before one examines the Index Mobile chronographs produced by Dubey & Schaldenbrand, it is worthwhile to describe -- briefly -- the operation of split-second chronographs and the state of the art, as it stood in the 1940's, before the development of the Index Mobile.

A split-second chronograph employs two chronograph second hands, which run together for a while, with the upper hand appearing to be superimposed on the lower hand. When the user wants to check an interval time, he presses a button, and that's when the magic happens -- one of the second hands stops (to mark the interval time) and the other hand continues to run. After a reading or interval measurement has been made, the user presses the button again, and the hand that had been stopped catches up with the hand that has been running continuously, and once again, they appear to be running together, as a single hand. [This "catching up" is where we get the term, "Rattrapante", from the French word, "rattrape", meaning "to catch up.] Such split-second chronographs are also called "double chronographs", or "Fly-Back Hand"

Split-second chronographs are very complicated, with a separate castle wheel and numerous other parts being required for the amazing task of stopping one second hand (while another continues) and then having the stopped second hand catch up and continue on, with the primary second hand. In addition to the additional castle wheel and additional second hand, the movement of a traditional split-second chronograph will include a split-second brake (which looks like pincers), a split-second wheel, a heart-shaped reset piece, and various additional springs and cams.

The (MY) Index Mobile -- 'The' Rattrapante

Seeing the usefulness of split second chronographs, but the issues associated with existing designs, George Dubey set out to develop a split-second chronograph that would be simpler in design and less expensive in production. Beginning with a standard Landeron or Venus movement, George Dubey created a split-second chronograph by adding an additional chronograph second hand, and connecting the two second hands with a hairspring, with the hairspring fully visible between the dial and the crystal. When the chronograph is started, both the second hands move together. The user stops the split-second (or index) hand by pushing the button in the center of the crown, which applies a brake to the wheel turning the hand. When this button is released, this second hand (which had been stopped) "catches up" with the other second hand, which has continued running throughout the period being timed.

The Index Mobile was thought of as a simple, elegant solution, to a complex horological problem -- it allowed an inexpensive Landeron or Venus movement to be modified for split-second timing. The "Index Mobile" system was a clever approach for the production of a split second chronograph. By adding a few parts, common movements were able to deliver exonomical, reliable split-second timing.


Well, I had been trying for a long time to acquire one of these, very outstanding pieces of engineering and Horology, but without success, finally I managed to purchase my 'NOS' Index Mobile.
It is from around 1950 (maybe earlier, impossible to know exactly), has a Champagne face, and of course 'Rattrapante' function. I LOVE it!

The movement is caliber Landeron 48, with screw balance wheel. Note these pictures are J Stein's. Mine is earlier with NO shock protection on Landeron movement!







The US patent. This is very cool too:


A young George Dubey. (magazine advert)



MINE, On the wrist - Note the center crown pusher:



Acknowledgements: Jeff Stein for his outstanding information and knowledge and Kathleen H. Pritchard."
 
1 - 3 of 3 Posts
Top