Music Box Ratchet Wheel

[MuensterMann]

I have an 8-day cuckoo, Regula 34 movement, that has a music box and dancers. All is working perfectly, except every few times (every few hours) when it is playing music there is a violent reaction of the chain/weight. It seems like it is getting hung up and then breaks free causing a jerking action. Upon closer inspection it seems that the chain doesn't quite catch a cog and then with a little more rotation of the wheel it falls back down on the cogs. I tried a new chain (Regula 8-day) and I confirmed it is not the chain. Below is a photo of the ratchet wheel. Looking for a new wheel there is one at Timesavers that seemed like it may work due to its description, but they told me it is not the right one for this application. Does anyone know where I can find a new wheel? Or, does anyone recognize this problem and can offer a tip to repair it??

Thanks!!

 

[JeffG]

Maybe check that the clicks are not slipping?
-Jeff

 

[Willie X]

Most of these chain wheels can be taken apart without to much trouble.
Open er up for a look-see. Willie X

 

[Jeff T]

look for a different chain perhaps its a hurbert herr wheel they use different links per foot. you might have to count the cogs on the wheel

 

[Robert Horneman]

I have an 8-day cuckoo, Regula 34 movement, that has a music box and dancers. All is working perfectly, except every few times (every few hours) when it is playing music there is a violent reaction of the chain/weight. It seems like it is getting hung up and then breaks free causing a jerking action. Upon closer inspection it seems that the chain doesn't quite catch a cog and then with a little more rotation of the wheel it falls back down on the cogs. I tried a new chain (Regula 8-day) and I confirmed it is not the chain. Below is a photo of the ratchet wheel. Looking for a new wheel there is one at Timesavers that seemed like it may work due to its description, but they told me it is not the right one for this application. Does anyone know where I can find a new wheel? Or, does anyone recognize this problem and can offer a tip to repair it?? View attachment 754949 Thanks!!

Could the chain go under the drive shaft? Looks like the chain is too high.

 

[MuensterMann]

The number of cogs on the wheel are 6. The problem also happens when winding in the other direction - and thus how I am now testing different chains - new and/or different about of links per foot. Between 2 cogs there is a link, that is, each cog has a link and there is one link between them. The problem is that at times there are two links of chain between the cogs, and since the next cog only grabs one that extra link just causes slack and when the slack tightens, there is the sudden jerkiness. I am trying a variety of different chains to see if chain links per foot or outstretched links is causing the issue. So far, no luck!

 

[JeffG]

The problem is that at times there are two links of chain between the cogs, and since the next cog only grabs one that extra link just causes slack and when the slack tightens, there is the sudden jerkiness.

Certainly sounds like a links-per-foot issue. Wishing you success!
-Jeff

 

[Willie X]

If the chain is right, force is only applied at the leading cog, on the weight side. The other (trailing) cogs will usually have a little space on both sides, inside the links. This space increases a tad with each cog as you go back to the tail end of the chain. With this in mind, it's usually easy to see if you need more or less links.

I did say "usually". Willie X

 

[MuensterMann]

I tried a few 8-day Regula chains (48 lpf, 120mm) and they all show the same issue on the wheel.

I then tried an 8-day Herr chain (45 lpf, 130mm) and it seems to work well without issues so far. Could it be that the music box was made to be compatible with a Herr 8-day cuckoo, but at the factory they matched it with a Regula 8-day cuckoo??

 

[JeffG]

Could it be that the music box was made to be compatible with a Herr 8-day cuckoo, but at the factory they matched it with a Regula 8-day cuckoo??

My guess is that a previous repairperson used parts that they had on hand to get the clock out the door, rather than ordering and waiting for the correct wheel.
-Jeff

 

[MuensterMann]

No, I think the music box and all its parts are original. I think that they clock was always like this.