Is this really necessary?

[NEW65]

I’m just rebuilding an hermle 1171 weight driven on cables. I’m going to add a picture to clearly show what I’m questioning:



Above showing clearly the component that is pushing onto the time train cable wheel which I think applies power but I’m just wondering if this is absolutely essential to include because I’ve had other 1171s that haven’t had this??
Can anyone comment on this? If it wasn’t included would time keeping be affected ?
Thanks

 

[Jim Hartog]

Hello NEW65,

Is that "maintaining power"?

Jim

 

[J. A. Olson]

See if the movement keeps ticking when it's being wound. If it does, then it's maintaining power as the time train gets wound.

 

[Dick Feldman]

It sure looks like maintaining power. If so, there is a small "main spring" internally that keeps tension on the time train when the clock is being wound. Not essential but a nice touch. Without maintaining power, the clock train may lag for the few seconds that the clock is being wound.
Dick

 

[J. A. Olson]

The chainwind Hermle 451/461 series movements I wind each week do not have maintaining power.
The time train stalls when being wound, which leaves one having to turn the minute hand forward just enough to make up for any loss that occurred when winding. Otherwise the clock will gradually appear to have slowed over time, even if regulated to the touch.

 

[MARK A. BUTTERWORTH]

Maintaining power is what keeps the escape wheel from going backwards when being round. Why would you remove that during a rebuilt?

 

[NEW65]

Thanks chaps for your replies, I did think it was related to maintaining power.
Mark, I only questioned it because I’ve rebuilt many 1171s and none of them have had this device fitted so I just wonder why this model has and not the others? It was just a query based on previous findings . I will of course refit it but glad I asked you people.
Thanks

 

[shutterbug]

The maintaining power will have its own very weak spring that is capable of keeping things working as you wind.

 

[wow]

The maintaining power will have its own very weak spring that is capable of keeping things working as you wind.

Some are mounted so the lever falls on top of the wheel and gravity controls it. For those who keep up with the “ to the second” accuracy of a clock”, it’s a great feature.