Gustav Becker chime struggle

[skinnb1]

I am an amateur with experience on a number of clocks including other examples of Gustav Becker clocks with Westminster chimes but I am struggling with this one. It as has been dismantled and cleaned and runs perfectly for days on end and has run perfectly for a couple of weeks in test. However, at random it seems, the clock stops because the levers causing the chime to operate jam and the minute wheel cannot lift the levers. If the jam is released the clock then carries on to work correctly for days.

On examination it seems that the jam happens at warning. The pin on the chime warning wheel seems to come to rest above the chime lever stopping it rising further and jamming.

The front plate is shown in the first picture (jammed). The second picture shows the pin resting on the top of the lever rather than in front of it. The third picture (from another occasion) shows the same situation from the front. The fourth picture is like the second, but perhaps slightly clearer.

I am struggling to know what is causing this to happen and because it is really intermittent I am struggling to figure out how to approach solving the problem. I can't create the problem and I only see the result after the problem has occurred.

Any ideas about possible causes and how to go about problem solving?

Thanks in advance for any help you can provide.

 

[Dick Feldman]

Without the movement in my hands, I cannot tell the absolute cause.
However, your symptoms are of a worn movement. All of the cleaning/lube/adjusting on this earth probably will not solve the wear. With the wear/friction cycle, the movement will run till extra energy is required. After that hurdle (warn) has passed, the clock will again run.
The normal solution for wear in clock movements is to install bushings at each wear point. Adding one or a few bushings may make the clock run but is normally only a stop gap measure till another wear point gets to a critical situation. Like a chain, the weakest link will stop the action.
A good article on bushing is here: Bushing Using Hand Tools

Once the escapement has plenty of power, the clock will likely run fine.

Dick

 

[dickstorer]

Maybe the warning run is to short. Try re-positioning the warning wheel. The stop pin on the warning wheel should be at least 90 degrees from the lifting lever when the chime train is at rest. This is what is happening, according to your description: The lifting lever is butting up directly under the stop pin. There is usually enough gear backlash that it will not happen every time.

 

[skinnb1]

Now resolved. I eventually discovered that the chime autocorrect wheel was not secure on its arbor and moved slightly over time. There is one arbor with one wheel with slots stopping the 1st 2nd and 4th quarter chimes, a further wheel with a single slot stopping the 3/4 chime, as well as a gear wheel and a pinion. The wheel providing the autocorrect on the 3/4 chime would move its position on the arbor slightly over time. A consequence was that after a while the wheel moved and the 3/4 chime did not stop correctly leading to further problems.It was cured with Loctite rather than a more horologially correct solution. I have secured that wheel and done no rebushing and it now appears to be stable and running correctly.I eventually realised that the slots had to be placed on the circumference in fractions of 10. i.e. to chime once at 15 past the wheel moves 1/10 of it's circumference, then 2/10 for the next quarter, then 3/10, then 4/10 and starts again.