Chains fall off

[schuh]

I'm helping a friend restore a grandfather clock with a Hermle movement. The movement is not in it's original case but has been installed in another case. The main problen is that the chains have literally fallen off the movement. I don't mean came off the sprockets, but rather the weights fell so far that the keepers on the chains went through the sprockets and and the chain fell to the bottom of the case. (I didn't know that was possible !).
So the question is ... what keeps the chains from unwinding too far and falling off the sprocket? Is it the weights landing on the bottom of the case or are the keepers supposed to stop when they encounter a hole in the woodpiece that supports the movement (sinilar to a cuckoo clock ) ?
The fact that the movement is not in the original case makes it non obvious.
Thanks for any help you can offer.

 

[wow]

Most modern grandfather clocks have stops on each winding arbor to keep that from happening but that is with cable movements. On many Hermle chain driven movements the seatboard has small holes that keep the chain ends from going into the movement. Some have retainers about four inches from the end that keep that from happening. Photos of what you have would help.

 

[Willie X]

On a well worn movement. If you remove the weight, with the weight near the top, the weight of the tail end of the chain will make the chain scoot over the chain-wheel and possibly to the floor.

The cure is: don't remove the weight unless the chains are about even, hook to tail.

Willie X

 

[Steve Neul]

I'm helping a friend restore a grandfather clock with a Hermle movement. The movement is not in it's original case but has been installed in another case. The main problen is that the chains have literally fallen off the movement. I don't mean came off the sprockets, but rather the weights fell so far that the keepers on the chains went through the sprockets and and the chain fell to the bottom of the case. (I didn't know that was possible !).
So the question is ... what keeps the chains from unwinding too far and falling off the sprocket? Is it the weights landing on the bottom of the case or are the keepers supposed to stop when they encounter a hole in the woodpiece that supports the movement (sinilar to a cuckoo clock ) ?
The fact that the movement is not in the original case makes it non obvious.
Thanks for any help you can offer.

On mine the weight will stop when it reaches the bottom of the case long before the other end reaches the movement. I wouldn't want to have to reach up into the movement to reach the keeper to wind it. Maybe longer chains is what you need.

 

[Willie X]

You say: "the chains have literally fallen off the movement". So ... does the weight fall to the floor (with the chain attached) or does the chain fall to the floor when the weight is removed??

Willie X

On mine the weight will stop when it reaches the bottom of the case long before the other end reaches the movement. I wouldn't want to have to reach up into the movement to reach the keeper to wind it. Maybe longer chains is what you need.

 

[NEW65]

I'm not understanding what is going here. One of my biggest call out problems after sales is when the owner removes the weight and the chain rapidly travels off the chain wheel! And you can take a safe bet that it will always be the middle chain! It depends on where the weight is - if near the top and the weight is removed, that chain must be held to ensure it stays on the chain wheel.
Not all of them do it.
The HM Kieninger chainwheels are the worst for this!
When you wind the clock is there an audible 'click'
Good luck

 

[Steve Neul]

I guess I'm just showing my ignorance, I only have experience with two modern movements. The movement I have you could remove the weight right up against the movement and the chain wouldn't move at all. It was probably made around 1980. Good to know about old movements.

 

[schuh]

Thank you all for the very helpful suggestions. I really appreciate the quick responses!
Unfortunately I wasn't there when the chains came off, so the scenario where someone took off a weight when near the top and the unbalanced chain was enough to unwind the rachet is possible. Also because the movement is not in its original case, there might have been holes in the base plate originally., which restricted the keepers. I will contact my friend today and see if he can better describe just how the chains came off. Thanks again and I will try to report back when I have more information.

 

[schuh]

Mystery Solved: I was able to contact my friend and he said his wife was preparing to move the clock and was removing the weights when the chains just slipped off. So apparently Willie was right when he guessed that it was the weight of the chain itself that unwound the ratchet.