The manual wind, medium sized pin lever movement EB 8461 was released in the 1970ies. Due to its rational construction, which left out all unneccessiary details, it was rather cheap and so used in fashion watches, among them the direct read watches, which were “in” that time. The version with direct read indication is presented here.Video on YouTube
The EB 8461 is a Roskopf like construction, which means, that the hands are only driven by the mainspring on the dial side, and not, like on non-Roskopf movements, on the movement side. The only exception is the directly driven center second.
The gear train is driven by the mainspring and consists of second wheel, third wheel, fourth wheel (which carries the center second hand) and escapement wheel.
The flat three-leg ring balance is beared in two different shock protections with metal bearings. On the dial side, it’s of unknown type, on the movement side it’s the pretty unusual Novochoc system. The only ruby on this movement is the finger of the balance. The balance still ticks with slow 18000 A/h.
The inner side of the gear train bridge hosts the odd winding click mechanism, which consists only of two parts, a U-shaped spring and a gear. Both are riveted and cannot be replaced.
On the EB 8461, we have a yoke winding system. It’s made in a rather simple construction, but it works well. The hand setting gear on the dial side is also riveted.
You can spot the hand setting wheel, which is drives the upper mainspring barrel wheel. This wheel is attached with a slip clutch onto the mainspring barrel and drives the minute cannon pinion. Unlike on true Roskopf movement, the hour wheel is not driven by a reverser on top of the mainspring barrel, but with own reverser wheel, located at “7”.
On the version with direct read indication, there’s no classic hour wheel, but a hour disc, which is driven by a three-teeth reverser wheel.
The direct read indication consists of a constantly driven minute disc, on the minute cannon pinion and a hour wheel with 12 teeth on its inner side which is advanced once per hour by the reverser wheel.
To esure proper switching and engagement, a punched spring is used:
When both discs are mounted, you hardly see anything else of the dial side:
In the lab
|Number of jewels:||1/17|
Nickel anular balance|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Hairspring key|
|Construction type:||pillar construction|
|Winding mechanism:||yoke winding system|
|Functions:||hour, minute, (second), (day)|
|Size:||8 1/2''' (measured: 19,3mm)|