13AP

Start Year
1934
Jewels
17
simpletreasures
Posted November 2, 2011 - 11:17pm

ENTERED INTO DATABASE ON 11/02/2011 Found in new model identified as "Champ" or "Astor". Possible "Shield" datecode. Datecode not verified.

Reverend Rob
Posted January 17, 2018 - 10:18am

Ok, a bit more info on this movement. Designed by Louis Müller and marketed in watches by Louis Müller & Cie, Bulova used this movt briefly in the 'Champ' model. Further digging reveals that another name for this company is Fabrique d'Horlogerie La Champagne.

They were also well known for the 'Wig Wag' automatic watch movt. 

Dates for the patent appear to be early 30's and Bulova examples date to 1936. (Square stamp) This movement had a movable stud carrier (rare for the time) and Breguet overcoil. 

Other names used by Müller are Dido, Mars, Aster, and Champ. I have said elsewhere that this was based on the FHF 29, but the keyless works are very different, so  this is incorrect. 

You can clearly see the calibre number stamped above, 28-20, which is the Champagne calibre. Despite this, it is my experience now that not all parts are interchangeable with the Bulova 13AP, particularly the balance. It was very common for Bulova to mod the balances on their ebauche based movts, and they obviously started doing this very early on. 

From the Watch-Wiki:

"La Champagne SA

Louis (Karl Ludwig) Müller took over his father's watch factory "La Champagne" in 1890 , founded in 1854 , and converted it into the corporation Louis Müller & Cie (later Louis Müller SA).
The company La Champagne SA Louis Müller & Cie. In 1931, in Biel, the so-called Wig-Wag automatic , an early automatic elevator system , was patented. In this construction, the entire movement moves as a flywheel on two side levers in a housing frame back and forth. For the elevator only one swing direction was used. The watches with this automatic vibrator were launched under the brand names Mars and Aster . In 1916 , Louis Affolter took over the position as head of the drive manufacturing and the journal turning workshop for escapement wheel works. His salary was 300.- Swiss Franks per month, with one week of paid holidays per year. He left this post at the end of April 1919 and became self-employed in Renan on May 1 of the same year.
The company was later continued (around 1960 ) by Nicolet Watch Co. of Charles Nicolet in Tramelan."
 
 
The Wig Wag watch mentioned was an entirely different animal, with a hidden crown. 
Geoff Baker
Posted January 7, 2018 - 7:44am

Photo supplied by member esk51

mybulova_admin
Posted January 12, 2018 - 9:23pm

All I could find was this: Patent No. 166843  (31-01-1934)

Inventor/s: FABRIQUE D HORLOGERIE LA CHAMP [CH] (FABRIQUE D'HORLOGERIE "LA CHAMPAGNE" LOUIS MUELLER & CIE. S. A)

Applicants:  HORLOGERIE LA CHAMPAGNE LOUI [CH] (FABRIQUE D'HORLOGERIE "LA CHAMPAGNE" LOUIS MUELLER & CIE. S. A)

Watch case serial number of belonging t the movement is 5258933, so we should date this to at least 1934 I guess.

So I assume that the part at the back acts as a pendulum and swings side to side ever so slightly, winding the main barrel spring.