The AS 740 shown here is a cylinder movement, probably one of the last cylinder movements by AS, for which existed spare parts until the 1940ies.
1926, AS, AM and FHF created the Ebauches SA for coordinating the ebauches production. From that time on, AS contentrated mainly on pallet lever movements, AM onto cylinder movements, FHF on lever movements and so on. So, the AS 740 might origin from the mid or late 1920ies.
The gilt base plate still reminds a lot of old (cylinder-) pocket watch movements and is covered with lots of small holes.
The gear train is absolutely typical for a cylinder movement with decentral second at 6 o’clock: Mainspring barrel - minute wheel - third wheel- large seconds wheel - cylinder wheel. Except for the cylinder wheel, all gears are beared under one single bridge, of which the bearings are just simple holes, no rubies. It’s pretty hard to insert all the gears simultaneously.
The cylinder wheel and the flat three-leg anular balance are ruby-beared, but a shock protection is of course not yet used. Both have got their own cocks.
On the dial side, there’s also nothing unusual, you can see here a rocking bar winding system with a very simple ratchet.
The speciality of the specimen shows here are its both hallmarks:
On the one hand a completely unknown ”AS” hallmark is used; on the other hand, on the movement side next to one of the dial screws another entirely unknown “EB” hallmark is stamped in. The latter would mean that the Ebauches Bettlach would have been involved in the production, which in 1932 joined the Ebauches SA. This in turn would mean that by 1932, according to the specialization of all, the two producers, the least expected cylinder movement manufacturers have produced this specimen, and not as AM or Felsa who were also part of the Ebauches SA since 1928 and well know for their cylinder movement production.
In the lab
|Number of jewels:||6|
Nickel anular balance|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||rocking bar winding system|
|Setting lever spring:||4 hole(s)|
|Functions:||hour, minute, decentral second|
|Size:||10 1/2''' (measured: 23,3mm)|
Flume: 1947 102|